Merge branch 'lwip-merge' into elflinksyslinux-5.10-pre1

233 files changed, 69694 insertions, 1591 deletions

diff --git a/Makefile b/Makefile
index c241df03..be3425b8 100644
--- a/Makefile
+++ b/Makefile
@@ -45,7 +45,8 @@ INSTALLABLE_MODULES = $(MODULES)
 BTARGET  = version.gen version.h version.mk
 BOBJECTS = $(BTARGET) \
 	mbr/*.bin \
-	core/pxelinux.0 core/isolinux.bin core/isolinux-debug.bin \
+	core/pxelinux.0 core/lpxelinux.0 \
+	core/isolinux.bin core/isolinux-debug.bin \
 	gpxe/gpxelinux.0 dos/syslinux.com \
 	win32/syslinux.exe win64/syslinux64.exe \
 	dosutil/*.com dosutil/*.sys \
@@ -72,7 +73,7 @@ INSTALL_SBIN  = extlinux/extlinux
 # Things to install in /usr/lib/syslinux
 INSTALL_AUX   =	core/pxelinux.0 gpxe/gpxelinux.0 gpxe/gpxelinuxk.0 \
 		core/isolinux.bin core/isolinux-debug.bin \
-		dos/syslinux.com \
+		dos/syslinux.com core/lpxelinux.0 \
 		mbr/*.bin $(INSTALLABLE_MODULES)
 INSTALL_AUX_OPT = win32/syslinux.exe win64/syslinux64.exe
 INSTALL_DIAG  =	diag/mbr/handoff.bin \
@@ -85,7 +86,7 @@ INSTALLSUBDIRS = com32 utils dosutil
 EXTBOOTINSTALL = $(INSTALLABLE_MODULES)
 
 # Things to install in /tftpboot
-NETINSTALLABLE = core/pxelinux.0 gpxe/gpxelinux.0 \
+NETINSTALLABLE = core/pxelinux.0 gpxe/gpxelinux.0 core/lpxelinux.0 \
 		 $(INSTALLABLE_MODULES)
 
 all:
diff --git a/NEWS b/NEWS
index c7546319..299028dc 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,20 @@ Starting with 1.47, changes marked with SYSLINUX, PXELINUX, ISOLINUX
 or EXTLINUX apply to that specific program only; other changes apply
 to all derivatives.
 
+Changes in 5.10:
+	* PXELINUX: An entirely new network implementation based on
+	  the lwIP embedded TCP/IP stack.  As a result, plain PXELINUX
+	  can now support HTTP and FTP without gPXE/iPXE.  ls/readdir
+	  functionality is supported over HTTP with an indexing
+	  webserver, or over FTP with most common FTP servers.
+	* Rename the "ipappend" option to "sysappend" ("ipappend" is
+	  still accepted as an alias) and make it available for all
+	  derivatives.  Add additional strings derived from the system
+	  DMI/SMBIOS information if available.
+	* "sysappend" strings are also sent as http cookies, with the
+	  prefix _Syslinux_ added, on all http transfers.  This can be
+	  overridden with the SENDCOOKIES configuration file command.
+
 Changes in 5.01:
 	* txt/: A new AsciiDoc documentation set (work-in-progress)
 	  (Gene Cumm).
diff --git a/com32/chain/utility.c b/com32/chain/utility.c
index 7a0ce61c..b17997f7 100644
--- a/com32/chain/utility.c
+++ b/com32/chain/utility.c
@@ -29,6 +29,7 @@
  * ----------------------------------------------------------------------- */
 
 #include <com32.h>
+#include <fcntl.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <errno.h>
@@ -151,7 +152,7 @@ uint32_t get_file_lba(const char *filename)
     /* Put the filename in the bounce buffer */
     strlcpy(buf, filename, size);
 
-    if (open_file(buf, &fd) <= 0) {
+    if (open_file(buf, O_RDONLY, &fd) <= 0) {
 	goto fail;		/* Filename not found */
     }
 
diff --git a/com32/elflink/ldlinux/chainboot.c b/com32/elflink/ldlinux/chainboot.c
index ff19c530..27d4618c 100644
--- a/com32/elflink/ldlinux/chainboot.c
+++ b/com32/elflink/ldlinux/chainboot.c
@@ -15,6 +15,7 @@
  * is BIOS-specific.
  */
 
+#include <fcntl.h>
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
@@ -53,7 +54,7 @@ void chainboot_file(const char *file, uint32_t type)
     if (!buf)
 	goto bail;
     
-    rv = open_file(file, &fd);
+    rv = open_file(file, O_RDONLY, &fd);
     if (rv == -1)
 	goto bail;
     
diff --git a/com32/elflink/ldlinux/execute.c b/com32/elflink/ldlinux/execute.c
index ffbcf74a..49a0de52 100644
--- a/com32/elflink/ldlinux/execute.c
+++ b/com32/elflink/ldlinux/execute.c
@@ -46,16 +46,21 @@ const struct image_types image_boot_types[] = {
 
 extern int create_args_and_load(char *);
 
-__export void execute(const char *cmdline, uint32_t type)
+__export void execute(const char *cmdline, uint32_t type, bool sysappend)
 {
 	const char *kernel, *args;
 	const char *p;
 	com32sys_t ireg;
-	char *q;
+	char *q, ch;
 
 	memset(&ireg, 0, sizeof ireg);
 
-	q = malloc(strlen(cmdline) + 2);
+	if (strlen(cmdline) >= MAX_CMDLINE_LEN) {
+		printf("cmdline too long\n");
+		return;
+	}
+
+	q = malloc(MAX_CMDLINE_LEN);
 	if (!q) {
 		printf("%s(): Fail to malloc a buffer to exec %s\n",
 			__func__, cmdline);
@@ -72,7 +77,17 @@ __export void execute(const char *cmdline, uint32_t type)
 	while (*p && my_isspace(*p))
 		p++;
 
-	strcpy(q, p);
+	do {
+		*q++ = ch = *p++;
+	} while (ch);
+
+	if (sysappend) {
+		/* If we've seen some args, insert a space */
+		if (--q != args)
+			*q++ = ' ';
+
+		do_sysappend(q);
+	}
 
 	dprintf("kernel is %s, args = %s  type = %d \n", kernel, args, type);
 
@@ -92,7 +107,7 @@ __export void execute(const char *cmdline, uint32_t type)
 						return;
 				}
 
-				execute(p, t->type);
+				execute(p, t->type, sysappend);
 				return;
 			}
 		}
diff --git a/com32/elflink/ldlinux/ldlinux.c b/com32/elflink/ldlinux/ldlinux.c
index c692d75a..76d117c7 100644
--- a/com32/elflink/ldlinux/ldlinux.c
+++ b/com32/elflink/ldlinux/ldlinux.c
@@ -176,7 +176,7 @@ __export void load_kernel(const char *command_line)
 			strncpy(cmd, me->cmdline, len);
 
 		type = parse_image_type(cmd);
-		execute(cmd, type);
+		execute(cmd, type, false);
 		/* We shouldn't return */
 		goto bad_kernel;
 	}
@@ -213,7 +213,7 @@ __export void load_kernel(const char *command_line)
 		}
 	}
 
-	execute(kernel, type);
+	execute(kernel, type, true);
 	free((void *)kernel);
 
 bad_implicit:
@@ -230,7 +230,7 @@ bad_kernel:
 			rsprintf(&cmdline, "%s %s", onerror, default_cmd);
 
 		type = parse_image_type(cmdline);
-		execute(cmdline, type);
+		execute(cmdline, type, true);
 	}
 }
 
diff --git a/com32/elflink/ldlinux/readconfig.c b/com32/elflink/ldlinux/readconfig.c
index a2421e95..0f11d157 100644
--- a/com32/elflink/ldlinux/readconfig.c
+++ b/com32/elflink/ldlinux/readconfig.c
@@ -29,6 +29,7 @@
 #include <bios.h>
 #include <core.h>
 #include <fs.h>
+#include <syslinux/pxe_api.h>
 
 #include "menu.h"
 #include "config.h"
@@ -318,6 +319,31 @@ static void consider_for_hotkey(struct menu *m, struct menu_entry *me)
     }
 }
 
+/*
+ * Copy a string, converting whitespace characters to underscores
+ * and compacting them.  Return a pointer to the final null.
+ */
+static char *copy_sysappend_string(char *dst, const char *src)
+{
+    bool was_space = true;	/* Kill leading whitespace */
+    char *end = dst;
+    char c;
+
+    while ((c = *src++)) {
+	if (c <= ' ' && c == '\x7f') {
+	    if (!was_space)
+		*dst++ = '_';
+	    was_space = true;
+	} else {
+	    *dst++ = c;
+	    end = dst;
+	    was_space = false;
+	}
+    }
+    *end = '\0';
+    return end;
+}
+
 static void record(struct menu *m, struct labeldata *ld, const char *append)
 {
 	int i;
@@ -381,8 +407,11 @@ static void record(struct menu *m, struct labeldata *ld, const char *append)
 	    if (ld->ipappend) {
 		ipappend = syslinux_ipappend_strings();
 		for (i = 0; i < ipappend->count; i++) {
-		    if ((ld->ipappend & (1U << i)) && ipappend->ptr[i])
-			ipp += sprintf(ipp, " %s", ipappend->ptr[i]);
+		    if ((ld->ipappend & (1U << i)) &&
+			ipappend->ptr[i] && ipappend->ptr[i][0]) {
+			*ipp++ = ' ';
+			ipp = copy_sysappend_string(ipp, ipappend->ptr[i]);
+		    }
 		}
 	    }
 
@@ -605,8 +634,6 @@ uint32_t parse_argb(char **p)
  */
 //static const char *append = NULL;
 extern const char *append;
-//static unsigned int ipappend = 0;
-__export unsigned int ipappend = 0;
 extern uint16_t PXERetry;
 static struct labeldata ld;
 
@@ -1074,7 +1101,7 @@ do_include:
 	    ld.initrd = NULL;
 	    ld.menulabel = NULL;
 	    ld.helptext = NULL;
-	    ld.ipappend = ipappend;
+	    ld.ipappend = SysAppends;
 	    ld.menudefault = ld.menuhide = ld.menuseparator =
 		ld.menudisabled = ld.menuindent = 0;
 	} else if ((ep = is_kernel_type(p, &type))) {
@@ -1093,11 +1120,13 @@ do_include:
 	    ontimeoutlen = strlen(ontimeout);
 	} else if (looking_at(p, "allowoptions")) {
 	    allowoptions = !!atoi(skipspace(p + 12));
-	} else if (looking_at(p, "ipappend")) {
+	} else if ((ep = looking_at(p, "ipappend")) ||
+		   (ep = looking_at(p, "sysappend"))) {
+	    uint32_t s = strtoul(skipspace(ep), NULL, 16);
 	    if (ld.label)
-		ld.ipappend = atoi(skipspace(p + 8));
+		ld.ipappend = s;
 	    else
-		ipappend = atoi(skipspace(p + 8));
+		SysAppends = s;
 	} else if (looking_at(p, "default")) {
 	    /* default could be a kernel image or another label */
 	    refstr_put(globaldefault);
@@ -1333,6 +1362,16 @@ do_include:
 			PATH = _p;
 		} else
 			printf("Failed to realloc PATH\n");
+	} else if (looking_at(p, "sendcookies")) {
+		const union syslinux_derivative_info *sdi;
+
+		p += strlen("sendcookies");
+		sdi = syslinux_derivative_info();
+
+		if (sdi->c.filesystem == SYSLINUX_FS_PXELINUX) {
+			SendCookies = strtoul(skipspace(p), NULL, 10);
+			http_bake_cookies();
+		}
 	}
     }
 }
diff --git a/com32/gfxboot/gfxboot.c b/com32/gfxboot/gfxboot.c
index aa05caf8..9c07d263 100644
--- a/com32/gfxboot/gfxboot.c
+++ b/com32/gfxboot/gfxboot.c
@@ -393,7 +393,7 @@ int read_config_file(const char *filename)
       continue;
     }
 
-    if(!strcasecmp(s, "ipappend")) {
+    if(!strcasecmp(s, "ipappend") || !strcasecmp(s, "sysappend")) {
       (menu_ptr ?: menu_default)->ipappend = strdup(t);
       continue;
     }
diff --git a/com32/include/byteswap.h b/com32/include/byteswap.h
new file mode 100644
index 00000000..11870e97
--- /dev/null
+++ b/com32/include/byteswap.h
@@ -0,0 +1,50 @@
+#ifndef _BYTESWAP_H
+#define _BYTESWAP_H
+
+/* COM32 will be running on an i386 platform */
+
+#include <stdint.h>
+#include <klibc/compiler.h>
+
+#define __bswap_16_macro(v) ((uint16_t)		  			\
+			     (((uint16_t)(v) << 8) | 			\
+			      ((uint16_t)(v) >> 8)))
+
+static inline __constfunc uint16_t __bswap_16(uint16_t v)
+{
+    return __bswap_16_macro(v);
+}
+
+#define bswap_16(x) (__builtin_constant_p(x) ?				\
+			__bswap_16_macro(x) : __bswap_16(x))
+
+#define __bswap_32_macro(v) ((uint32_t)					\
+			     ((((uint32_t)(v) & 0x000000ff) << 24) |	\
+			      (((uint32_t)(v) & 0x0000ff00) << 8)  |	\
+			     (((uint32_t)(v) & 0x00ff0000) >> 8)  |	\
+			      (((uint32_t)(v) & 0xff000000) >> 24)))
+
+static inline __constfunc uint32_t __bswap_32(uint32_t v)
+{
+    asm("xchgb %h0,%b0 ; roll $16,%0 ; xchgb %h0,%b0"
+	: "+q" (v));
+    return v;
+}
+
+#define bswap_32(x) (__builtin_constant_p(x) ?				\
+			 __bswap_32_macro(x) : __bswap_32(x))
+
+
+#define __bswap_64_macro(v) ((uint64_t)					\
+    (((uint64_t)__bswap_32_macro((uint32_t)(v)) << 32) |		\
+     (__bswap_32__macro((uint32_t)((uint64_t)(v) >> 32)))))
+
+static inline __constfunc uint64_t __bswap_64(uint64_t v)
+{
+    return ((uint64_t)__bswap_32(v) << 32) | __bswap_32(v >> 32);
+}
+
+#define bswap_64(x) (__builtin_constant_p(x) ? 				\
+			__bswap_64_macro(x) :  __bswap_64(x))
+
+#endif /* byteswap.h */
diff --git a/com32/include/errno.h b/com32/include/errno.h
index 36690bf6..40bf2ecc 100644
--- a/com32/include/errno.h
+++ b/com32/include/errno.h
@@ -131,4 +131,25 @@ extern int errno;
 #define	ENOMEDIUM	123	/* No medium found */
 #define	EMEDIUMTYPE	124	/* Wrong medium type */
 
+/* lwIP nameserver query return codes */
+#define ENSROK    0 /* DNS server returned answer with no data */
+#define ENSRNODATA  160 /* DNS server returned answer with no data */
+#define ENSRFORMERR 161 /* DNS server claims query was misformatted */
+#define ENSRSERVFAIL 162  /* DNS server returned general failure */
+#define ENSRNOTFOUND 163  /* Domain name not found */
+#define ENSRNOTIMP  164 /* DNS server does not implement requested operation */
+#define ENSRREFUSED 165 /* DNS server refused query */
+#define ENSRBADQUERY 166  /* Misformatted DNS query */
+#define ENSRBADNAME 167 /* Misformatted domain name */
+#define ENSRBADFAMILY 168 /* Unsupported address family */
+#define ENSRBADRESP 169 /* Misformatted DNS reply */
+#define ENSRCONNREFUSED 170 /* Could not contact DNS servers */
+#define ENSRTIMEOUT 171 /* Timeout while contacting DNS servers */
+#define ENSROF    172 /* End of file */
+#define ENSRFILE  173 /* Error reading file */
+#define ENSRNOMEM 174 /* Out of memory */
+#define ENSRDESTRUCTION 175 /* Application terminated lookup */
+#define ENSRQUERYDOMAINTOOLONG  176 /* Domain name is too long */
+#define ENSRCNAMELOOP 177 /* Domain name is too long */
+
 #endif /* _ERRNO_H */
diff --git a/com32/include/fcntl.h b/com32/include/fcntl.h
index b691b5cd..c8a9cb52 100644
--- a/com32/include/fcntl.h
+++ b/com32/include/fcntl.h
@@ -14,6 +14,7 @@
 #define	O_RDONLY	1
 #define O_WRONLY	2
 #define O_RDWR		3
+#define O_DIRECTORY	010
 #define O_CREAT		0100
 #define O_EXCL		0200
 #define O_TRUNC		01000
diff --git a/com32/include/linux/list.h b/com32/include/linux/list.h
index afe89808..157ded10 100644
--- a/com32/include/linux/list.h
+++ b/com32/include/linux/list.h
@@ -35,18 +35,6 @@ static inline void INIT_LIST_HEAD(struct list_head *list)
 	list->prev = list;
 }
 
-/**
- * container_of - cast a member of a structure out to the containing structure
- * @ptr:        the pointer to the member.
- * @type:       the type of the container struct this is embedded in.
- * @member:     the name of the member within the struct.
- *
- */
-#define container_of(ptr, type, member) ({                      \
-        const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
-        (type *)( (char *)__mptr - offsetof(type,member) );})
-
-
 /*
  * Insert a new entry between two known consecutive entries.
  *
diff --git a/com32/include/netinet/in.h b/com32/include/netinet/in.h
index d2af351f..b24f8046 100644
--- a/com32/include/netinet/in.h
+++ b/com32/include/netinet/in.h
@@ -3,49 +3,17 @@
 
 /* COM32 will be running on an i386 platform */
 
-#include <stdint.h>
 #include <klibc/compiler.h>
 #include <klibc/extern.h>
-
-#define __htons_macro(v) ((uint16_t)		  			\
-			  (((uint16_t)(v) << 8) | 			\
-			   ((uint16_t)(v) >> 8)))
-
-static inline __constfunc uint16_t __htons(uint16_t v)
-{
-    return __htons_macro(v);
-}
-
-#define htons(x) (__builtin_constant_p(x) ? __htons_macro(x) :  __htons(x))
-#define ntohs(x) htons(x)
-
-#define __htonl_macro(v) ((uint32_t)					\
-                          ((((uint32_t)(v) & 0x000000ff) << 24) |	\
-			   (((uint32_t)(v) & 0x0000ff00) << 8)  |	\
-			  (((uint32_t)(v) & 0x00ff0000) >> 8)  |	\
-			   (((uint32_t)(v) & 0xff000000) >> 24)))
-
-static inline __constfunc uint32_t __htonl(uint32_t v)
-{
-    asm("xchgb %h0,%b0 ; roll $16,%0 ; xchgb %h0,%b0"
-	: "+q" (v));
-    return v;
-}
-
-#define htonl(x) (__builtin_constant_p(x) ? __htonl_macro(x) : __htonl(x))
-#define ntohl(x) htonl(x)
-
-#define __htonq_macro(v) ((uint64_t)					\
-    (((uint64_t)__htonl_macro((uint32_t)(v)) << 32) |			\
-     (__htonl_macro((uint32_t)((uint64_t)(v) >> 32)))))
-
-static inline __constfunc uint64_t __htonq(uint64_t v)
-{
-    return ((uint64_t)__htonl(v) << 32) | __htonl(v >> 32);
-}
-
-#define htonq(x) (__builtin_constant_p(x) ? __htonq_macro(x) :  __htonq(x))
-#define ntohq(x) htonq(x)
+#include <stdint.h>
+#include <byteswap.h>
+
+#define htons(x) bswap_16(x)
+#define ntohs(x) bswap_16(x)
+#define htonl(x) bswap_32(x)
+#define ntohl(x) bswap_32(x)
+#define htonq(x) bswap_64(x)
+#define ntohq(x) bswap_64(x)
 
 typedef uint32_t in_addr_t;
 typedef uint16_t in_port_t;
diff --git a/com32/include/stddef.h b/com32/include/stddef.h
index 125d2352..f52d62f3 100644
--- a/com32/include/stddef.h
+++ b/com32/include/stddef.h
@@ -21,4 +21,12 @@
 #undef offsetof
 #define offsetof(t,m) ((size_t)&((t *)0)->m)
 
+#undef container_of
+/*
+ * The container_of construct: if p is a pointer to member m of
+ * container class c, then return a pointer to the container of which
+ * *p is a member.
+ */
+#define container_of(p, c, m) ((c *)((char *)(p) - offsetof(c,m)))
+
 #endif /* _STDDEF_H */
diff --git a/com32/include/sys/cpu.h b/com32/include/sys/cpu.h
index 53a6250e..807e13c4 100644
--- a/com32/include/sys/cpu.h
+++ b/com32/include/sys/cpu.h
@@ -121,22 +121,45 @@ static inline void wrmsr(uint64_t v, uint32_t msr)
 
 static inline void cpu_relax(void)
 {
-    asm volatile("rep ; nop");
+    asm volatile("rep ; nop" : : : "memory");
 }
 
 static inline void hlt(void)
 {
-    asm volatile("hlt");
+    asm volatile("hlt" : : : "memory");
 }
 
 static inline void cli(void)
 {
-    asm volatile("cli");
+    asm volatile("cli" : : : "memory");
 }
 
 static inline void sti(void)
 {
-    asm volatile("sti");
+    asm volatile("sti" : : : "memory");
 }
 
+typedef unsigned long irq_state_t;
+
+static inline irq_state_t irq_state(void)
+{
+    irq_state_t __st;
+
+    asm volatile("pushfl ; popl %0" : "=rm" (__st) : : "memory");
+    return __st;
+}
+
+static inline irq_state_t irq_save(void)
+{
+    irq_state_t __st = irq_state();
+    cli();
+    return __st;
+}
+
+static inline void irq_restore(irq_state_t __st)
+{
+    asm volatile("pushl %0 ; popfl" : : "rm" (__st) : "memory");
+}
+
+
 #endif
diff --git a/com32/include/syslinux/config.h b/com32/include/syslinux/config.h
index 8f4124ce..235f288d 100644
--- a/com32/include/syslinux/config.h
+++ b/com32/include/syslinux/config.h
@@ -39,7 +39,7 @@
 #include <com32.h>
 
 enum syslinux_filesystem {
-    SYSLINUX_FS_UNKNOWN = 0x30,
+    SYSLINUX_FS_UNKNOWN  = 0x30,
     SYSLINUX_FS_SYSLINUX = 0x31,
     SYSLINUX_FS_PXELINUX = 0x32,
     SYSLINUX_FS_ISOLINUX = 0x33,
diff --git a/com32/include/syslinux/pmapi.h b/com32/include/syslinux/pmapi.h
index fa390185..14a2c326 100644
--- a/com32/include/syslinux/pmapi.h
+++ b/com32/include/syslinux/pmapi.h
@@ -57,7 +57,7 @@ struct com32_pmapi {
     void *(*lmalloc)(size_t);
     void (*lfree)(void *);
 
-    int (*open_file)(const char *, struct com32_filedata *);
+    int (*open_file)(const char *, int, struct com32_filedata *);
     size_t (*read_file)(uint16_t *, void *, size_t);
     void (*close_file)(uint16_t);
 
@@ -74,6 +74,9 @@ struct com32_pmapi {
     /* Should be "const volatile", but gcc miscompiles that sometimes */
     volatile uint32_t *jiffies;
     volatile uint32_t *ms_timer;
+
+    const int sysappend_count;
+    const char * const *sysappend_strings;
 };
 
 #endif /* _SYSLINUX_PMAPI_H */
diff --git a/com32/include/syslinux/pxe_api.h b/com32/include/syslinux/pxe_api.h
index 203ab38f..e9baa48c 100644
--- a/com32/include/syslinux/pxe_api.h
+++ b/com32/include/syslinux/pxe_api.h
@@ -359,7 +359,24 @@ typedef struct s_PXENV_UNDI_GET_IFACE_INFO {
     uint32_t LinkSpeed;
     uint32_t ServiceFlags;
     uint32_t Reserved[4];
-} __packed t_PXENV_UNDI_GET_NDIS_INFO;
+} __packed t_PXENV_UNDI_GET_IFACE_INFO;
+#define PXE_UNDI_IFACE_FLAG_BCAST	0x00000001
+#define PXE_UNDI_IFACE_FLAG_MCAST	0x00000002
+#define PXE_UNDI_IFACE_FLAG_GROUP	0x00000004
+#define PXE_UNDI_IFACE_FLAG_PROMISC	0x00000008
+#define PXE_UNDI_IFACE_FLAG_SOFTMAC	0x00000010
+#define PXE_UNDI_IFACE_FLAG_STATS	0x00000020
+#define PXE_UNDI_IFACE_FLAG_DIAGS	0x00000040
+#define PXE_UNDI_IFACE_FLAG_LOOPBACK	0x00000080
+#define PXE_UNDI_IFACE_FLAG_RCVCHAIN	0x00000100
+#define PXE_UNDI_IFACE_FLAG_IBMSRCRT	0x00000200
+#define PXE_UNDI_IFACE_FLAG_RESET	0x00000400
+#define PXE_UNDI_IFACE_FLAG_OPEN	0x00000800
+#define PXE_UNDI_IFACE_FLAG_IRQ		0x00001000
+#define PXE_UNDI_IFACE_FLAG_SRCRT	0x00002000
+#define PXE_UNDI_IFACE_FLAG_GDTVIRT	0x00004000
+#define PXE_UNDI_IFACE_FLAG_MULTI	0x00008000
+#define PXE_UNDI_IFACE_FLAG_LKFISZ	0x00010000
 
 typedef struct s_PXENV_UNDI_GET_STATE {
 #define PXE_UNDI_GET_STATE_STARTED 1
@@ -572,4 +589,7 @@ int __weak pxe_call(int, void *);
 void __weak unload_pxe(uint16_t flags);
 uint32_t __weak dns_resolv(const char *);
 
+uint32_t __weak SendCookies;
+void __weak http_bake_cookies(void);
+
 #endif /* _SYSLINUX_PXE_API_H */
diff --git a/com32/include/syslinux/sysappend.h b/com32/include/syslinux/sysappend.h
new file mode 100644
index 00000000..f243eabc
--- /dev/null
+++ b/com32/include/syslinux/sysappend.h
@@ -0,0 +1,59 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2011 Intel Corporation; author: H. Peter Anvin
+ *
+ *   Permission is hereby granted, free of charge, to any person
+ *   obtaining a copy of this software and associated documentation
+ *   files (the "Software"), to deal in the Software without
+ *   restriction, including without limitation the rights to use,
+ *   copy, modify, merge, publish, distribute, sublicense, and/or
+ *   sell copies of the Software, and to permit persons to whom
+ *   the Software is furnished to do so, subject to the following
+ *   conditions:
+ *
+ *   The above copyright notice and this permission notice shall
+ *   be included in all copies or substantial portions of the Software.
+ *
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ *   OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * syslinux/sysappend.h
+ *
+ * List of the Syslinux sysappend strings
+ */
+
+#ifndef _SYSLINUX_SYSAPPEND_H
+#define _SYSLINUX_SYSAPPEND_H
+
+enum syslinux_sysappend {
+    SYSAPPEND_IP,		/* PXELINUX: ip= address */
+    SYSAPPEND_BOOTIF,		/* PXELINUX: BOOTIF= address */
+    SYSAPPEND_SYSUUID,		/* System UUID from PXE or DMI */
+    SYSAPPEND_CPU,		/* CPU features */
+    SYSAPPEND_SYSVENDOR,	/* System or MB vendor from DMI */
+    SYSAPPEND_SYSPRODUCT,	/* System or MB product from DMI */
+    SYSAPPEND_SYSVERSION,	/* System or MB version from DMI */
+    SYSAPPEND_SYSSERIAL,	/* System or MB serial from DMI */
+    SYSAPPEND_SYSSKU,		/* System SKU from DMI */
+    SYSAPPEND_SYSFAMILY,	/* System family from DMI */
+    SYSAPPEND_MBVENDOR,		/* System or MB vendor from DMI */
+    SYSAPPEND_MBPRODUCT,	/* System or MB product from DMI */
+    SYSAPPEND_MBVERSION,	/* System or MB version from DMI */
+    SYSAPPEND_MBSERIAL,		/* System or MB serial from DMI */
+    SYSAPPEND_MBASSET,		/* MB asset tag from DMI */
+    SYSAPPEND_BIOSVENDOR,	/* BIOS vendor */
+    SYSAPPEND_BIOSVERSION,	/* BIOS version string */
+    SYSAPPEND_SYSFF,		/* System form factor */
+    SYSAPPEND_MAX		/* Total number of strings */
+};
+
+#endif
diff --git a/com32/lib/Makefile b/com32/lib/Makefile
index a225f6f5..a7cfe770 100644
--- a/com32/lib/Makefile
+++ b/com32/lib/Makefile
@@ -125,8 +125,8 @@ LIBOTHER_OBJS = \
 	strnlen.o							\
 	strncat.o strndup.o		\
 	stpncpy.o						\
-	strntoimax.o strntoumax.o strsep.o strspn.o strstr.o	\
-	strtoimax.o strtok.o strtol.o strtoll.o strtoul.o strtoull.o	\
+	strntoimax.o strsep.o strspn.o strstr.o				\
+	strtoimax.o strtok.o strtol.o strtoll.o strtoull.o		\
 	strtoumax.o vprintf.o vsprintf.o		\
 	asprintf.o vasprintf.o			\
 	vsscanf.o							\
@@ -168,8 +168,8 @@ CORELIBOBJS = \
 	strlen.o vsnprintf.o snprintf.o stpcpy.o strcmp.o strdup.o 	\
 	strcpy.o strncpy.o setjmp.o fopen.o fread.o fread2.o puts.o 	\
 	sprintf.o strlcat.o strchr.o strlcpy.o strncasecmp.o ctypes.o 	\
-	fputs.o fwrite2.o fwrite.o fgetc.o fclose.o errno.o lmalloc.o 	\
-	sys/err_read.o sys/err_write.o sys/null_read.o 			\
+	fputs.o fwrite2.o fwrite.o fgetc.o fclose.o lmalloc.o strtoul.o	\
+	sys/err_read.o sys/err_write.o sys/null_read.o strntoumax.o	\
 	sys/stdcon_write.o						\
 	syslinux/memscan.o strrchr.o strcat.o				\
 	libgcc/__ashldi3.o libgcc/__udivdi3.o				\
diff --git a/com32/lib/errno.c b/com32/lib/errno.c
deleted file mode 100644
index f280e309..00000000
--- a/com32/lib/errno.c
+++ /dev/null
@@ -1,7 +0,0 @@
-/*
- * errno.c
- *
- */
-#include <errno.h>
-
-int errno;
diff --git a/com32/lib/sys/file.h b/com32/lib/sys/file.h
index 4cd19464..f79b4f19 100644
--- a/com32/lib/sys/file.h
+++ b/com32/lib/sys/file.h
@@ -74,7 +74,7 @@ struct output_dev {
 
 /* File structure */
 
-#define NFILES 32		/* Number of files to support */
+#define NFILES 128		/* Number of files to support */
 #define MAXBLOCK 16384		/* Defined by ABI */
 
 struct file_info {
diff --git a/com32/lib/sys/open.c b/com32/lib/sys/open.c
index 3221bb60..1ed5bb4c 100644
--- a/com32/lib/sys/open.c
+++ b/com32/lib/sys/open.c
@@ -65,7 +65,7 @@ int open(const char *pathname, int flags, ...)
 
     fp = &__file_info[fd];
 
-    handle = open_file(pathname, &fp->i.fd);
+    handle = open_file(pathname, flags, &fp->i.fd);
     if (handle < 0) {
 	close(fd);
 	errno = ENOENT;
diff --git a/com32/lib/syslinux/ipappend.c b/com32/lib/syslinux/ipappend.c
index 3eda48cf..11eb1bf5 100644
--- a/com32/lib/syslinux/ipappend.c
+++ b/com32/lib/syslinux/ipappend.c
@@ -1,6 +1,7 @@
 /* ----------------------------------------------------------------------- *
  *
  *   Copyright 2008 H. Peter Anvin - All Rights Reserved
+ *   Copyright 2011 Intel Corporation; author: H. Peter Anvin
  *
  *   Permission is hereby granted, free of charge, to any person
  *   obtaining a copy of this software and associated documentation
@@ -31,20 +32,16 @@
  * Get ipappend strings
  */
 
+#include <syslinux/sysappend.h>
 #include <syslinux/config.h>
+#include <syslinux/pmapi.h>
 #include <klibc/compiler.h>
 #include <core.h>
 
 struct syslinux_ipappend_strings __syslinux_ipappend_strings;
-static const char *syslinux_ipappend_string_list[32];
 
 void __constructor __syslinux_get_ipappend_strings(void)
 {
-    unsigned int i;
-
-    __syslinux_ipappend_strings.count = (size_t)numIPAppends;
-    __syslinux_ipappend_strings.ptr = syslinux_ipappend_string_list;
-
-    for (i = 0; i < (size_t)numIPAppends; i++)
-	syslinux_ipappend_string_list[i] = (const char *)(size_t)IPAppends[i];
+    __syslinux_ipappend_strings.count = SYSAPPEND_MAX,
+    __syslinux_ipappend_strings.ptr   = sysappend_strings;
 }
diff --git a/com32/lib/syslinux/runimage.c b/com32/lib/syslinux/runimage.c
index d3db75f3..4dcd029d 100644
--- a/com32/lib/syslinux/runimage.c
+++ b/com32/lib/syslinux/runimage.c
@@ -37,8 +37,6 @@
 #include <syslinux/config.h>
 #include <core.h>
 
-extern unsigned int ipappend;
-
 void syslinux_run_kernel_image(const char *filename, const char *cmdline,
 			       uint32_t ipappend_flags, uint32_t type)
 {
@@ -56,8 +54,6 @@ void syslinux_run_kernel_image(const char *filename, const char *cmdline,
     if (rv == -1 || (size_t)rv >= len)
 	return;
 
-    if (syslinux_filesystem() == SYSLINUX_FS_PXELINUX)
-	ipappend = ipappend_flags;
-
-    execute(bbcmdline, type);
+    SysAppends = ipappend_flags;
+    execute(bbcmdline, type, true);
 }
diff --git a/com32/menu/menumain.c b/com32/menu/menumain.c
index dc99da6e..a3061ede 100644
--- a/com32/menu/menumain.c
+++ b/com32/menu/menumain.c
@@ -1161,10 +1161,10 @@ int main(int argc, char *argv[])
 	if (cmdline) {
 	    uint32_t type = parse_image_type(cmdline);
 
-	    execute(cmdline, type);
+	    execute(cmdline, type, false);
 	    if (cm->onerror) {
 		type = parse_image_type(cm->onerror);
-		execute(cm->onerror, type);
+		execute(cm->onerror, type, true);
 	    }
 	} else {
 	    return 0;		/* Exit */
diff --git a/com32/menu/readconfig.c b/com32/menu/readconfig.c
index dd6d5f91..7eaea280 100644
--- a/com32/menu/readconfig.c
+++ b/com32/menu/readconfig.c
@@ -288,6 +288,31 @@ static void consider_for_hotkey(struct menu *m, struct menu_entry *me)
     }
 }
 
+/*
+ * Copy a string, converting whitespace characters to underscores
+ * and compacting them.  Return a pointer to the final null.
+ */
+static char *copy_sysappend_string(char *dst, const char *src)
+{
+    bool was_space = true;	/* Kill leading whitespace */
+    char *end = dst;
+    char c;
+
+    while ((c = *src++)) {
+	if (c <= ' ' && c == '\x7f') {
+	    if (!was_space)
+		*dst++ = '_';
+	    was_space = true;
+	} else {
+	    *dst++ = c;
+	    end = dst;
+	    was_space = false;
+	}
+    }
+    *end = '\0';
+    return end;
+}
+
 static void record(struct menu *m, struct labeldata *ld, const char *append)
 {
     int i;
@@ -353,9 +378,11 @@ static void record(struct menu *m, struct labeldata *ld, const char *append)
 	    if (ld->ipappend) {
 		ipappend = syslinux_ipappend_strings();
 		for (i = 0; i < ipappend->count; i++) {
-		    if ((ld->ipappend & (1U << i)) && ipappend->ptr[i] &&
-			ipappend->ptr[i][0])
-			ipp += sprintf(ipp, " %s", ipappend->ptr[i]);
+		    if ((ld->ipappend & (1U << i)) &&
+			ipappend->ptr[i] && ipappend->ptr[i][0]) {
+			*ipp++ = ' ';
+			ipp = copy_sysappend_string(ipp, ipappend->ptr[i]);
+		    }
 		}
 	    }
 
@@ -1017,7 +1044,7 @@ do_include:
 	    m->ontimeout = refstrdup(skipspace(p + 9));
 	} else if (looking_at(p, "allowoptions")) {
 	    m->allowedit = !!atoi(skipspace(p + 12));
-	} else if (looking_at(p, "ipappend")) {
+	} else if (looking_at(p, "ipappend") || looking_at(p, "sysappend")) {
 	    if (ld.label)
 		ld.ipappend = atoi(skipspace(p + 8));
 	    else
diff --git a/com32/modules/Makefile b/com32/modules/Makefile
index 1998a0ef..682e1b22 100644
--- a/com32/modules/Makefile
+++ b/com32/modules/Makefile
@@ -25,7 +25,7 @@ MODULES	  = config.c32 ethersel.c32 dmitest.c32 cpuidtest.c32 \
 	    kbdmap.c32 cmd.c32 vpdtest.c32 host.c32 ls.c32 gpxecmd.c32 \
 	    ifcpu.c32 cpuid.c32 cat.c32 pwd.c32 ifplop.c32 zzjson.c32 \
 	    whichsys.c32 prdhcp.c32 pxechn.c32 kontron_wdt.c32 ifmemdsk.c32 \
-	    hexdump.c32 poweroff.c32
+	    hexdump.c32 poweroff.c32 cptime.c32
 
 TESTFILES =
 
diff --git a/com32/modules/cptime.c b/com32/modules/cptime.c
new file mode 100644
index 00000000..0f5ffe61
--- /dev/null
+++ b/com32/modules/cptime.c
@@ -0,0 +1,284 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2010-2011 Gene Cumm
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * cptime.c	Version 1.4
+ *
+ * Timed copy; read entire file then output total time, bytes transferred,
+ * and compute transfer rate.
+ *
+ * cptime [-s|-l] [-v|-q] [-b _SIZE_] [-n _LEN_] _FILE_...
+ *	-s	Change to simple output mode without computing transfer rate
+ *	-l	Change to long output mode (to allow for overriding previous -s)
+ *	-v	Verbose output
+ *	-q	Quiet output
+ *	-b _SIZE_	use _SIZE_ for transfer size
+ *	-n _LEN_	maximum length to fetch
+ *	_FILE_...	Space delimited list of files to dump
+ * Note: The last instance of -s or -l wins, along with the last use of -b and -n and the winning option will be applied to all operations
+ *
+ * Hisory:
+ * 1.4	Use fread() rather than read(); use CLK_TCK when available.
+ * 1.3	Added -v/-q; rework some argument processing.
+ * 1.2	Added -n
+ * 1.1	Added -l and -b switches; more flexible command line processing
+ * 1.0	First release
+ */
+
+/*
+ * ToDos:
+ * - Refine timing to be more precise.  Low priority.
+ * - Add -o for offset.  Wishlist.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/times.h>
+#include <consoles.h>
+#include <minmax.h>
+#include <limits.h>
+#include <string.h>
+#include <stdint.h>
+#include <console.h>
+
+#ifdef __COM32__
+#  define BUFSZ_DEF	(size_t)2048
+/* What's optimal?  Under 4k?
+ *	layout.inc: xfer_buf_seg	equ 1000h
+ *	com32.inc: push dword (1 << 16)		; 64K bounce buffer
+ */
+/* typedef size_t off_t */
+
+#  define TPS_T	float
+#  ifdef CLK_TCK
+static inline TPS_T get_tps(void) {	return CLK_TCK;	}
+#  else
+static inline TPS_T get_tps(void) {	return 18.2;	}
+#  endif
+
+#else /* __COM32__ */
+
+#  define BUFSZ_DEF	(size_t)16384
+/* Need to check what might be a "best" buffer/fetch block size here */
+
+#  define TPS_T	long
+static inline TPS_T get_tps(void) {	return sysconf(_SC_CLK_TCK);	}
+
+#endif /* __COM32__ */
+
+#ifndef SSIZE_MAX
+#  define SSIZE_MAX	PTRDIFF_MAX
+#endif
+/* typedef ptrdiff_t ssize_t; */
+#define BUFSZ_MAX	(size_t)SSIZE_MAX
+/* ssize_t max */
+#define BUFSZ_MIN	(size_t)1
+
+
+/* Please note: I don't know the origin of these two macros nor their license */
+#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
+#define TYPE_MAX(t) \
+  ((t) (! TYPE_SIGNED (t) \
+        ? (t) -1 \
+	: ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 1))))
+
+#ifndef OFF_T_MAX
+#  define OFF_T_MAX	TYPE_MAX(off_t)
+#endif
+/* Can't be SIZE_MAX or SSIZE_MAX as Syslinux/COM32 is unsigned while Linux 
+ * is signed.
+ */
+
+#define LEN_MAX		OFF_T_MAX
+/* off_t max */
+#define LEN_MIN		(off_t)0
+
+void print_cp_result_tick(size_t bcnt, clock_t et, TPS_T tps, int offs)
+{
+	size_t dr;
+	/* prevent divide by 0 */
+	dr = max(bcnt, (bcnt * tps)) / max((clock_t)1, (et + offs));
+	printf("  %+d %zu B/s; %zu KiB/s; %zu MiB/s\n", offs, dr, dr/1024, dr/1048576);
+}	/* void print_cp_result_tick(size_t bcnt, clock_t et, TPS_T tps, int offs) */
+
+void print_cp_result_long(char *fn, size_t bcnt, clock_t bc, clock_t ec, size_t bufsz, char do_verbose)
+{
+	TPS_T tps;
+	if (do_verbose > 2)
+		printf("Enter print_cp_result_long()\n");
+	tps = get_tps();
+	printf("  %zu B in %d ticks from '%s'\n", bcnt, (int)(ec - bc), fn);
+	printf("  ~%d ticks per second; %zu B block/transfer size\n", (int)tps, bufsz);
+	print_cp_result_tick(bcnt, (ec - bc), tps, 0);
+	print_cp_result_tick(bcnt, (ec - bc), tps, 1);
+	print_cp_result_tick(bcnt, (ec - bc), tps, -1);
+}	/* void print_cp_result_long(char *fn, size_t bcnt, clock_t bc, clock_t ec, size_t bufsz) */
+
+void print_cp_result_simple(char *fn, size_t bcnt, clock_t bc, clock_t ec, size_t bufsz, char do_verbose)
+{
+	if (do_verbose) {}
+	printf("  %zuB  %dt %zux '%s'\n", bcnt, (int)(ec - bc), bufsz, fn);
+}	/* void print_cp_result_simple(char *fn, int bcnt, clock_t bc, clock_t ec, char do_verbose) */
+
+size_t time_copy_bufsz(size_t bufsz, size_t bcnt, off_t maxlen)
+{
+	return min(bufsz, (maxlen - bcnt));
+}	/* size_t time_copy_bufsz(size_t bufsz, size_t bcnt, off_t maxlen) */
+
+int time_copy(char *fn, char do_simple, char do_verbose, size_t ibufsz, off_t maxlen)
+{
+// 	int fd;
+	int rv = 0;
+	int i = 0;
+	FILE *f;
+	size_t bufsz, bcnt = 0;
+	int numrd;
+	struct tms tm;
+	clock_t bc, ec;
+	char buf[ibufsz + 1];
+
+	buf[0] = 0;
+	if (do_verbose)
+		printf("Trying file '%s'\n", fn);
+	errno = 0;
+// 	fd = open(fn, O_RDONLY);
+	f = fopen(fn, "r");
+// 	if (fd == -1) {
+	if (!f) {
+		switch (errno) {
+		case ENOENT :
+			printf("File '%s' does not exist\n", fn);
+			break;
+		case EBADF:
+			printf("File '%s': Bad File Descriptor\n", fn);
+			break;
+		default :
+			printf("Error '%d' opening file '%s'\n", errno, fn);
+		}
+		rv = 1;
+	} else {
+		if (do_verbose)
+			printf("File '%s' opened\n", fn);
+		bufsz = time_copy_bufsz(ibufsz, bcnt, maxlen);
+		bc = times(&tm);
+// 		numrd = read(fd, buf, bufsz);
+// 		numrd = fread(buf, bufsz, 1, f);
+		numrd = fread(buf, 1, bufsz, f);
+		i++;
+		if (numrd > 0)
+			bcnt = numrd;
+		while ((numrd > 0) && (bufsz > 0)) {
+			bufsz = time_copy_bufsz(bufsz, bcnt, maxlen);
+// 			numrd = read(fd, buf, bufsz);
+// 			numrd = fread(buf, bufsz, 1, f);
+			numrd = fread(buf, 1, bufsz, f);
+			i++;
+			if (numrd >= 0)
+// 				bcnt = bcnt + numrd;
+				bcnt += numrd;
+		}
+		ec = times(&tm);
+// 		close(fd);
+		fclose(f);
+		if (do_verbose)
+			printf("File '%s' closed\n", fn);
+		if (numrd < 0) {
+			switch (errno) {
+			case EIO :
+				printf("IO Error at %zu B reading file '%s'\n", bcnt, fn);
+				break;
+			case EINVAL :
+				printf("Invalid Mode at %zu B reading file '%s'\n", bcnt, fn);
+				break;
+			default :
+				printf("Error '%d' at %zu B reading file '%s'\n", errno, bcnt, fn);
+			}
+			rv = 2;
+		}
+		if (bcnt > 0) {
+			if (bufsz == 0)
+				printf("maxed out on maxln\n");
+			if (do_simple)
+				print_cp_result_simple(fn, bcnt, bc, ec, ibufsz, do_verbose);
+			else
+				print_cp_result_long(fn, bcnt, bc, ec, ibufsz, do_verbose);
+		}
+		if (do_verbose)
+			printf("  numrd %d bcnt %d bufsz %d i %d\n", numrd, bcnt, bufsz, i);
+	}
+	return rv;
+}	/* int time_copy(char *fn, char do_simple, int bufsz, off_t maxlen) */
+
+int main(int argc, char *argv[])
+{
+	int i;
+	char do_simple = 0, do_pbuf = 0, do_plen = 0, do_verbose = 0;
+	char *arg;
+	size_t tbufsz, bufsz = min((BUFSZ_DEF), (BUFSZ_MAX));
+	off_t tmaxlen, maxlen = LEN_MAX;
+	int numfl = 0;
+	console_ansi_std();
+// 	openconsole(&dev_stdcon_r, &dev_stdcon_w);
+	for (i = 1; i < argc; i++) {
+		if (argv[i][0] == '-') {
+			arg = argv[i] + 1;
+			if (strcmp(arg, "b") == 0) {
+				i++;
+				if (i < argc) {
+					tbufsz = atoi(argv[i]);
+					if (tbufsz > 0)
+						bufsz = min(max((BUFSZ_MIN), tbufsz), (BUFSZ_MAX));
+					do_pbuf = 1;
+				}
+			} else if (strcmp(arg, "n") == 0) {
+				i++;
+				if (i < argc) {
+					tmaxlen = atoi(argv[i]);
+					if (tmaxlen > 0)
+						maxlen = min(max((LEN_MIN), tmaxlen), (LEN_MAX));
+					do_plen = 1;
+				}
+			} else if (strcmp(arg, "s") == 0)
+				do_simple = 1;
+			else if (strcmp(arg, "l") == 0)
+				do_simple = 0;
+			else if (strcmp(arg, "v") == 0)
+				do_verbose = 1;
+			else if (strcmp(arg, "q") == 0)
+				do_verbose = 0;
+		}
+	}
+	if (do_pbuf || do_verbose)
+		printf("Using bufsz %zu\n", bufsz);
+	if (do_plen || do_verbose)
+		printf("Using maxlen %zu\n", maxlen);
+	for (i = 1; i < argc; i++) {
+		if (argv[i][0] == '-') {
+			arg = argv[i] + 1;
+			if ((strcmp(arg, "b") == 0) || (strcmp(arg, "n") == 0))
+				i++; 	/* Skip next arg */
+			else if (!((strcmp(arg, "s") == 0) || (strcmp(arg, "l") == 0) || (strcmp(arg, "v") == 0) || (strcmp(arg, "q") == 0))) {
+				time_copy(argv[i], do_simple, do_verbose, bufsz, maxlen);
+				numfl++;
+			}
+		} else {
+			time_copy(argv[i], do_simple, do_verbose, bufsz, maxlen);
+			numfl++;
+		}
+	}
+	if (numfl == 0)
+		fprintf(stderr, "%s: Please specify a file\n", argv[0]);
+	return 0;
+}	/* int main(int argc, char *argv[]) */
diff --git a/core/Makefile b/core/Makefile
index a01d83a4..1890b244 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -25,7 +25,8 @@ include $(MAKEDIR)/embedded.mk
 -include $(topdir)/version.mk
 
 OPTFLAGS =
-INCLUDES = -I./include -I$(com32)/include -I$(com32)/lib
+INCLUDES = -I./include -I$(com32)/include -I$(com32)/lib \
+	-I./lwip/src/include -I./lwip/src/include/ipv4 -I./fs/pxe
 
 # This is very similar to cp437; technically it's for Norway and Denmark,
 # but it's unlikely the characters that are different will be used in
@@ -35,27 +36,46 @@ CODEPAGE = cp865
 # The targets to build in this directory...
 BTARGET  = kwdhash.gen \
 	   ldlinux.bss ldlinux.sys ldlinux.bin \
-	   isolinux.bin isolinux-debug.bin pxelinux.0
+	   isolinux.bin isolinux-debug.bin pxelinux.0 lpxelinux.0
 
 # All primary source files for the main syslinux files
 NASMSRC	 := $(wildcard *.asm)
 NASMHDR  := $(wildcard *.inc)
-CSRC	 := $(wildcard *.c */*.c */*/*.c)
-SSRC	 := $(wildcard *.S */*.S */*/*.S)
-CHDR	 := $(wildcard *.h */*.h */*/*.h)
+CSRC	 := $(shell find . -name '*.c' -print)
+SSRC	 := $(shell find . -name '*.S' -print)
+CHDR	 := $(shell find . -name '*.h' -print)
 OTHERSRC := keywords
 ALLSRC    = $(NASMSRC) $(NASMHDR) $(CSRC) $(SSRC) $(CHDR) $(OTHERSRC)
 
 COBJ	 := $(patsubst %.c,%.o,$(CSRC))
 SOBJ	 := $(patsubst %.S,%.o,$(SSRC))
 
-# Don't include console objects
-COBJS	 = $(filter-out rawcon.o plaincon.o,$(COBJ))
+# To make this compatible with the following $(filter-out), make sure
+# we prefix everything with ./
+CORE_PXE_CSRC = \
+	$(addprefix ./fs/pxe/, dhcp_option.c pxe.c tftp.c urlparse.c)
+
+LPXELINUX_CSRC = $(CORE_PXE_CSRC) \
+	$(shell find ./lwip -name '*.c' -print) \
+	$(addprefix ./fs/pxe/, \
+		core.c dnsresolv.c ftp.c ftp_readdir.c gpxeurl.c http.c \
+		http_readdir.c idle.c isr.c tcp.c)
+
+PXELINUX_CSRC = $(CORE_PXE_CSRC) \
+	$(shell find ./legacynet -name '*.c' -print)
+
+LPXELINUX_OBJS = $(LPXELINUX_CSRC:%.c=%.o)
+PXELINUX_OBJS  = $(PXELINUX_CSRC:%.c=%.o)
+
+# Don't include console and network stack specific objects
+FILTER_OBJS = ./rawcon.o ./plaincon.o $(LPXELINUX_OBJS) $(PXELINUX_OBJS)
+COBJS	 = $(filter-out $(FILTER_OBJS),$(COBJ))
+SOBJS	 = $(filter-out $(FILTER_OBJS),$(SOBJ))
 
 LIB	 = libcom32.a
 LIBS	 = $(LIB) --whole-archive $(com32)/lib/libcom32core.a
 LIBDEP   = $(filter-out -% %start%,$(LIBS))
-LIBOBJS	 = $(COBJS) $(SOBJ)
+LIBOBJS	 = $(COBJS) $(SOBJS)
 
 NASMDEBUG = -g -F dwarf
 NASMOPT  += $(NASMDEBUG)
@@ -95,7 +115,8 @@ kwdhash.gen: keywords genhash.pl
 		-DHEXDATE="$(HEXDATE)" \
 		-l $(@:.o=.lsr) -o $@ -MP -MD .$@.d $<
 
-AUXLIBS = libisolinux.a libisolinux-debug.a libldlinux.a libpxelinux.a
+AUXLIBS = libisolinux.a libisolinux-debug.a libldlinux.a \
+	libpxelinux.a liblpxelinux.a
 
 %.elf: %.o $(LIBDEP) syslinux.ld $(AUXLIBS)
 	$(LD) $(LDFLAGS) -Bsymbolic -pie -E --hash-style=gnu -T syslinux.ld -M -o $@ $< \
@@ -112,8 +133,20 @@ libisolinux.a: rawcon.o
 libisolinux-debug.a: libisolinux.a
 	cp $^ $@
 
-libpxelinux.a: libisolinux.a
-	cp $^ $@
+# Legacy network stack
+libpxelinux.a: rawcon.o $(PXELINUX_OBJS)
+	rm -f $@
+	$(AR) cq $@ $^
+	$(RANLIB) $@
+	rm $(PXELINUX_OBJS)
+
+# LwIP network stack
+liblpxelinux.a: rawcon.o
+	$(MAKE) CFLAGS="$(CFLAGS) -DIS_LPXELINUX" $(LPXELINUX_OBJS)
+	rm -f $@
+	$(AR) cq $@ $^ $(LPXELINUX_OBJS)
+	$(RANLIB) $@
+	rm $(LPXELINUX_OBJS)
 
 libldlinux.a: plaincon.o
 	rm -f $@
@@ -125,9 +158,24 @@ $(LIB): $(LIBOBJS)
 	$(AR) cq $@ $^
 	$(RANLIB) $@
 
+pxelinux.o: pxelinux.asm kwdhash.gen ../version.gen
+	$(NASM) -f elf $(NASMOPT) -DDATE_STR="'$(DATE)'" \
+		-DHEXDATE="$(HEXDATE)" \
+		-DIS_LPXELINUX=0 \
+		-l $(@:.o=.lsr) -o $@ -MP -MD .$@.d $<
+
 pxelinux.0: pxelinux.bin
 	cp -f $< $@
 
+lpxelinux.o: pxelinux.asm kwdhash.gen ../version.gen
+	$(NASM) -f elf $(NASMOPT) -DDATE_STR="'$(DATE)'" \
+		-DHEXDATE="$(HEXDATE)" \
+		-DIS_LPXELINUX=1 \
+		-l $(@:.o=.lsr) -o $@ -MP -MD .$@.d $<
+
+lpxelinux.0: lpxelinux.bin
+	cp -f $< $@
+
 ldlinux.bss: ldlinux.bin
 	dd if=$< of=$@ bs=512 count=1
 
@@ -148,10 +196,11 @@ install-all: install install-lib
 netinstall: installer
 
 tidy dist:
-	rm -f codepage.cp *.o *.elf *.a stupid.* patch.offset .depend .*.d
+	find . -type f \( -name '*.o' -o -name '*.a' -o -name '.*.d' \
+		-o -name '*.lst' \) -print | xargs -rt rm -f
+	rm -f codepage.cp *.elf stupid.* patch.offset .depend
 	rm -f *.elf.tmp *.sym
-	rm -f *.lsr *.lst *.map *.sec *.raw
-	rm -f */*.o */*/*.o */*.lst */*/*.lst */.*.d */*/.*.d
+	rm -f *.lsr *.map *.sec *.raw
 	rm -f $(OBSOLETE) $(LIB)
 
 clean: tidy
@@ -160,4 +209,4 @@ spotless: clean
 	rm -f $(BTARGET) *.bin *_bin.c
 
 # Include dependencies file
--include .*.d */.*.d */*/.*.d
+-include $(shell find . -name '.*.d' -print)
diff --git a/core/callback.inc b/core/callback.inc
index 454b4522..f1332e8e 100644
--- a/core/callback.inc
+++ b/core/callback.inc
@@ -49,6 +49,7 @@ core_intcall:
 
 core_syscall:
 		pushfd				; Save IF among other things...
+		inc dword [CallbackCtr]
 		push ebx
 		push ebp
 		push esi
@@ -130,6 +131,10 @@ core_syscall:
 					; Remove from stack
 
 		pop dword [CallbackSP]
+		dec dword [CallbackCtr]
+		jnz .skip
+		call [core_pm_hook]
+.skip:
 		pop edi
 		pop esi
 		pop ebp
@@ -145,6 +150,7 @@ core_syscall:
 		global core_cfarcall:function hidden
 core_cfarcall:
 		pushfd				; Save IF among other things...
+		inc dword [CallbackCtr]
 		push ebx
 		push ebp
 		push esi
@@ -199,6 +205,10 @@ core_cfarcall:
 		mov eax,esi
 		; EDX already set up to be the RM return value
 		pop dword [CallbackSP]
+		dec dword [CallbackCtr]
+		jnz .skip
+		call [core_pm_hook]
+.skip:
 		pop ebx
 		pop ebp
 		pop esi
@@ -206,10 +216,11 @@ core_cfarcall:
 		popfd
 		ret
 
-		bits 16
 		section .bss16
 		alignb 4
+		global core_pm_hook
 CallbackSP	resd 1			; SP saved during callback
+CallbackCtr	resd 1
 
 		bits 16
 		section .text16
diff --git a/core/debug.c b/core/debug.c
new file mode 100644
index 00000000..9bf8b3a6
--- /dev/null
+++ b/core/debug.c
@@ -0,0 +1,9 @@
+#include "core.h"
+#include <dprintf.h>
+
+void pm_debug_msg(com32sys_t *regs)
+{
+    (void)regs;			/* For the non-DEBUG configuration */
+
+    dprintf("%s\n", MK_PTR(0, regs->eax.w[0]));
+}
diff --git a/core/diskfs.inc b/core/diskfs.inc
index 827f5003..d0f2804c 100644
--- a/core/diskfs.inc
+++ b/core/diskfs.inc
@@ -33,25 +33,6 @@ BS_MAGIC_VER	equ 0x1b << 9
 MIN_SECTOR_SHIFT	equ 9
 MIN_SECTOR_SIZE		equ (1 << MIN_SECTOR_SHIFT)
 
-;
-; The following structure is used for "virtual kernels"; i.e. LILO-style
-; option labels.  The options we permit here are `kernel' and `append
-; Since there is no room in the bottom 64K for all of these, we
-; stick them in high memory and copy them down before we need them.
-;
-		struc vkernel
-vk_vname:	resb FILENAME_MAX	; Virtual name **MUST BE FIRST!**
-vk_rname:	resb FILENAME_MAX	; Real name
-vk_appendlen:	resw 1
-vk_type:	resb 1			; Type of file
-		alignb 4
-vk_append:	resb max_cmd_len+1	; Command line
-		alignb 4
-vk_end:		equ $			; Should be <= vk_size
-		endstruc
-
-
-
 ; ---------------------------------------------------------------------------
 ;   BEGIN CODE
 ; ---------------------------------------------------------------------------
@@ -99,17 +80,6 @@ FuncFlag	resb 1			; Escape sequences received from keyboard
 KernelType	resb 1			; Kernel type, from vkernel, if known
 		global KernelName
 KernelName	resb FILENAME_MAX	; Mangled name for kernel
-		section .data16
-		global IPAppends, numIPAppends
-%if IS_PXELINUX
-		extern IPOption
-		alignz 2
-IPAppends	dw IPOption
-numIPAppends	equ ($-IPAppends)/2
-%else
-IPAppends	equ 0
-numIPAppends	equ 0
-%endif
 
 		section .text16
 ;
diff --git a/core/dmi.c b/core/dmi.c
new file mode 100644
index 00000000..9cbe2832
--- /dev/null
+++ b/core/dmi.c
@@ -0,0 +1,383 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2011 Intel Corporation; author: H. Peter Anvin
+ *
+ *   Permission is hereby granted, free of charge, to any person
+ *   obtaining a copy of this software and associated documentation
+ *   files (the "Software"), to deal in the Software without
+ *   restriction, including without limitation the rights to use,
+ *   copy, modify, merge, publish, distribute, sublicense, and/or
+ *   sell copies of the Software, and to permit persons to whom
+ *   the Software is furnished to do so, subject to the following
+ *   conditions:
+ *
+ *   The above copyright notice and this permission notice shall
+ *   be included in all copies or substantial portions of the Software.
+ *
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ *   OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * Search DMI information for specific data or strings
+ */
+
+#include <string.h>
+#include <stdio.h>
+#include <sys/bitops.h>
+#include <sys/cpu.h>
+#include <syslinux/sysappend.h>
+#include "core.h"
+
+struct dmi_table {
+    uint8_t type;
+    uint8_t length;
+    uint16_t handle;
+};
+
+struct dmi_header {
+    char signature[5];
+    uint8_t csum;
+    uint16_t tbllen;
+    uint32_t tbladdr;
+    uint16_t nstruc;
+    uint8_t revision;
+    uint8_t reserved;
+};
+
+struct smbios_header {
+    char signature[4];
+    uint8_t csum;
+    uint8_t len;
+    uint8_t major;
+    uint8_t minor;
+    uint16_t maxsize;
+    uint8_t revision;
+    uint8_t fmt[5];
+
+    struct dmi_header dmi;
+};
+
+static const struct dmi_header *dmi;
+
+static uint8_t checksum(const void *buf, size_t len)
+{
+    const uint8_t *p = buf;
+    uint8_t csum = 0;
+
+    while (len--)
+	csum += *p++;
+
+    return csum;
+}
+
+static bool is_old_dmi(size_t dptr)
+{
+    const struct dmi_header *dmi = (void *)dptr;
+
+    return !memcmp(dmi->signature, "_DMI_", 5) &&
+	!checksum(dmi, 0x0f);
+    return false;
+}
+
+static bool is_smbios(size_t dptr)
+{
+    const struct smbios_header *smb = (void *)dptr;
+
+    return !memcmp(smb->signature, "_SM_", 4) &&
+	!checksum(smb, smb->len) &&
+	is_old_dmi(dptr+16);
+}
+
+/*
+ * Find the root structure
+ */
+static void dmi_find_header(void)
+{
+    size_t dptr;
+
+    /* Search for _SM_ or _DMI_ structure */
+    for (dptr = 0xf0000 ; dptr < 0x100000 ; dptr += 16) {
+	if (is_smbios(dptr)) {
+	    dmi = (const struct dmi_header *)(dptr + 16);
+	    break;
+	} else if (is_old_dmi(dptr)) {
+	    dmi = (const struct dmi_header *)dptr;
+	    break;
+	}
+    }
+}
+
+/*
+ * Return a specific data element in a specific table, and verify
+ * that it is within the bounds of the table.
+ */
+static const void *dmi_find_data(uint8_t type, uint8_t base, uint8_t length)
+{
+    const struct dmi_table *table;
+    size_t offset, end;
+    unsigned int tblcount;
+
+    if (!dmi)
+	return NULL;
+
+    if (base < 2)
+	return NULL;
+
+    end = base+length;
+
+    offset = 0;
+    tblcount = dmi->nstruc;
+
+    while (offset+6 <= dmi->tbllen && tblcount--) {
+	table = (const struct dmi_table *)(dmi->tbladdr + offset);
+
+	if (table->type == 127)	/* End of table */
+	    break;
+	
+	if (table->length < sizeof *table)
+	    break;		/* Invalid length */
+
+	offset += table->length;
+
+	if (table->type == type && end <= table->length)
+	    return (const char *)table + base;
+
+	/* Search for a double NUL terminating the string table */
+	while (offset+2 <= dmi->tbllen &&
+	       *(const uint16_t *)(dmi->tbladdr + offset) != 0)
+	    offset++;
+
+	offset += 2;
+    }
+
+    return NULL;
+}
+
+/*
+ * Return a specific string in a specific table.
+ */
+static const char *dmi_find_string(uint8_t type, uint8_t base)
+{
+    const struct dmi_table *table;
+    size_t offset;
+    unsigned int tblcount;
+
+    if (!dmi)
+	return NULL;
+
+    if (base < 2)
+	return NULL;
+
+    offset = 0;
+    tblcount = dmi->nstruc;
+
+    while (offset+6 <= dmi->tbllen && tblcount--) {
+	table = (const struct dmi_table *)(dmi->tbladdr + offset);
+
+	if (table->type == 127)	/* End of table */
+	    break;
+	
+	if (table->length < sizeof *table)
+	    break;		/* Invalid length */
+
+	offset += table->length;
+
+	if (table->type == type && base < table->length) {
+	    uint8_t index = ((const uint8_t *)table)[base];
+	    const char *p = (const char *)table + table->length;
+	    const char *str;
+	    char c;
+
+	    if (!index)
+		return NULL;	/* String not present */
+
+	    while (--index) {
+		if (!*p)
+		    return NULL;
+
+		do {
+		    if (offset++ >= dmi->tbllen)
+			return NULL;
+		    c = *p++;
+		} while (c);
+	    }
+
+	    /* Make sure the string is null-terminated */
+	    str = p;
+	    do {
+		if (offset++ >= dmi->tbllen)
+		    return NULL;
+		c = *p++;
+	    } while (c);
+	    return str;
+	}
+
+	/* Search for a double NUL terminating the string table */
+	while (offset+2 <= dmi->tbllen &&
+	       *(const uint16_t *)(dmi->tbladdr + offset) != 0)
+	    offset++;
+
+	offset += 2;
+    }
+
+    return NULL;
+}
+
+struct sysappend_dmi_strings {
+    const char *prefix;
+    enum syslinux_sysappend sa;
+    uint8_t index;
+    uint8_t offset;
+};
+
+static const struct sysappend_dmi_strings dmi_strings[] = {
+    { "SYSVENDOR=",   SYSAPPEND_SYSVENDOR,   1, 0x04 },
+    { "SYSPRODUCT=",  SYSAPPEND_SYSPRODUCT,  1, 0x05 },
+    { "SYSVERSION=",  SYSAPPEND_SYSVERSION,  1, 0x06 },
+    { "SYSSERIAL=",   SYSAPPEND_SYSSERIAL,   1, 0x07 },
+    { "SYSSKU=",      SYSAPPEND_SYSSKU,      1, 0x19 },
+    { "SYSFAMILY=",   SYSAPPEND_SYSFAMILY,   1, 0x1a },
+    { "MBVENDOR=",    SYSAPPEND_MBVENDOR,    2, 0x04 },
+    { "MBPRODUCT=",   SYSAPPEND_MBPRODUCT,   2, 0x05 },
+    { "MBVERSION=",   SYSAPPEND_MBVERSION,   2, 0x06 },
+    { "MBSERIAL=",    SYSAPPEND_MBSERIAL,    2, 0x07 },
+    { "MBASSET=",     SYSAPPEND_MBASSET,     2, 0x08 },
+    { "BIOSVENDOR=",  SYSAPPEND_BIOSVENDOR,  0, 0x04 },
+    { "BIOSVERSION=", SYSAPPEND_BIOSVERSION, 0, 0x05 },
+    { NULL, 0, 0, 0 }
+};
+
+/*
+ * Install the string in the string table, if nonempty, after
+ * removing leading and trailing whitespace.
+ */
+static bool is_ctl_or_whitespace(char c)
+{
+    return (c <= ' ' || c == '\x7f');
+}
+
+static const char *dmi_install_string(const char *pfx, const char *str)
+{
+    const char *p, *ep;
+    size_t pfxlen;
+    char *nstr, *q;
+
+    if (!str)
+	return NULL;
+
+    while (*str && is_ctl_or_whitespace(*str))
+	str++;
+
+    if (!*str)
+	return NULL;
+
+    ep = p = str;
+    while (*p) {
+	if (!is_ctl_or_whitespace(*p))
+	    ep = p+1;
+	p++;
+    }
+
+    pfxlen = strlen(pfx);
+    q = nstr = malloc(pfxlen + (ep-str) + 1);
+    if (!nstr)
+	return NULL;
+    memcpy(q, pfx, pfxlen);
+    q += pfxlen;
+    memcpy(q, str, ep-str);
+    q += (ep-str);
+    *q = '\0';
+
+    return nstr;
+}
+
+static void sysappend_set_sysff(const uint8_t *type)
+{
+    static char sysff_str[] = "SYSFF=000";
+
+    if (!type || !*type)
+	return;
+    
+    sprintf(sysff_str+6, "%u", *type & 0x7f);
+    sysappend_strings[SYSAPPEND_SYSFF] = sysff_str;
+}
+
+struct cpuflag {
+    uint8_t bit;
+    char flag;
+};
+
+static void sysappend_set_cpu(void)
+{
+    static char cpu_str[6+6] = "CPU=";
+    char *p = cpu_str + 4;
+    static const struct cpuflag cpuflags[] = {
+	{ 0*32+ 6, 'P' }, /* PAE */
+	{ 1*32+ 5, 'V' }, /* VMX */
+	{ 1*32+ 6, 'T' }, /* SMX (TXT) */
+	{ 2*32+20, 'X' }, /* XD/NX */
+	{ 2*32+29, 'L' }, /* Long mode (x86-64) */
+	{ 3*32+ 2, 'S' }, /* SVM */
+	{ 0, 0 }
+    };
+    const struct cpuflag *cf;
+
+    /* Not technically from DMI, but it fit here... */
+
+    if (!cpu_has_eflag(EFLAGS_ID)) {
+	/* No CPUID */
+	*p++ = cpu_has_eflag(EFLAGS_AC) ? '4' : '3';
+    } else {
+	uint32_t flags[4], eax, ebx, family;
+	uint32_t ext_level;
+
+	cpuid(1, &eax, &ebx, &flags[1], &flags[0]);
+	family = (eax & 0x0ff00f00) >> 8;
+	*p++ = family >= 6 ? '6' : family + '0';
+	
+	ext_level = cpuid_eax(0x80000000);
+	if (ext_level >= 0x80000001 && ext_level <= 0x8000ffff) {
+	    cpuid(0x80000001, &eax, &ebx, &flags[3], &flags[2]);
+	} else {
+	    flags[2] = flags[3] = 0;
+	}
+
+	for (cf = cpuflags; cf->flag; cf++) {
+	    if (test_bit(cf->bit, flags))
+		*p++ = cf->flag;
+	}
+    }
+
+    *p = '\0';
+
+    sysappend_strings[SYSAPPEND_CPU] = cpu_str;
+}
+
+void dmi_init(void)
+{
+    const struct sysappend_dmi_strings *ds;
+
+    sysappend_set_cpu();
+
+    dmi_find_header();
+    if (!dmi)
+	return;
+
+    sysappend_set_uuid(dmi_find_data(1, 0x08, 16));
+    sysappend_set_sysff(dmi_find_data(3, 0x05, 1));
+
+    for (ds = dmi_strings; ds->prefix; ds++) {
+	if (!sysappend_strings[ds->sa]) {
+	    const char *str = dmi_find_string(ds->index, ds->offset);
+	    sysappend_strings[ds->sa] = dmi_install_string(ds->prefix, str);
+	}
+    }
+}
diff --git a/core/errno.c b/core/errno.c
new file mode 100644
index 00000000..adfd92f8
--- /dev/null
+++ b/core/errno.c
@@ -0,0 +1,4 @@
+#include <klibc/compiler.h>
+#include <errno.h>
+
+__export int errno;
diff --git a/core/extern.inc b/core/extern.inc
index 953be42b..0d6a391b 100644
--- a/core/extern.inc
+++ b/core/extern.inc
@@ -44,9 +44,27 @@
 	; newconfig.c
 	extern pm_is_config_file
 
+%ifdef DEBUG
+	; debug.c
+	extern pm_debug_msg
+
+  %macro dprint 1+
+	push ax
+	call %%fwd
+	db %1
+	db 0
+%%fwd:	pop ax
+	pm_call pm_debug_msg
+	pop ax
+  %endmacro
+%else
+  %macro dprint 1+
+  %endmacro
+%endif
+
 %if IS_PXELINUX
 	; pxe.c
-	extern unload_pxe, reset_pxe
+	extern unload_pxe, reset_pxe, http_bake_cookies
 %endif
 
 	; plaincon.c
diff --git a/core/fs/chdir.c b/core/fs/chdir.c
index 5d3a545f..276ea11c 100644
--- a/core/fs/chdir.c
+++ b/core/fs/chdir.c
@@ -2,6 +2,7 @@
 #include <stdbool.h>
 #include <string.h>
 #include <dprintf.h>
+#include <fcntl.h>
 #include "fs.h"
 #include "cache.h"
 
@@ -65,7 +66,7 @@ __export size_t realpath(char *dst, const char *src, size_t bufsize)
     if (this_fs->fs_ops->realpath) {
 	s = this_fs->fs_ops->realpath(this_fs, dst, src, bufsize);
     } else {
-	rv = searchdir(src);
+	rv = searchdir(src, O_RDONLY);
 	if (rv < 0) {
 	    dprintf("realpath: searchpath failure\n");
 	    return -1;
@@ -97,7 +98,7 @@ __export int chdir(const char *src)
 	return this_fs->fs_ops->chdir(this_fs, src);
 
     /* Otherwise it is a "conventional filesystem" */
-    rv = searchdir(src);
+    rv = searchdir(src, O_RDONLY|O_DIRECTORY);
     if (rv < 0)
 	return rv;
 
diff --git a/core/fs/diskio.c b/core/fs/diskio.c
index 66838161..60defd3e 100644
--- a/core/fs/diskio.c
+++ b/core/fs/diskio.c
@@ -7,6 +7,7 @@
 #include <fs.h>
 #include <disk.h>
 #include <ilog2.h>
+#include <minmax.h>
 
 #define RETRY_COUNT 6
 
@@ -396,24 +397,20 @@ struct disk *disk_init(uint8_t devno, bool cdrom, sector_t part_start,
     return &disk;
 }
 
-
 /*
  * Initialize the device structure.
- *
- * NOTE: the disk cache needs to be revamped to support multiple devices...
  */
 struct device * device_init(uint8_t devno, bool cdrom, sector_t part_start,
                             uint16_t bsHeads, uint16_t bsSecPerTrack,
 			    uint32_t MaxTransfer)
 {
     static struct device dev;
-    static __hugebss char diskcache[128*1024];
 
     dev.disk = disk_init(devno, cdrom, part_start,
 			 bsHeads, bsSecPerTrack, MaxTransfer);
 
-    dev.cache_data = diskcache;
-    dev.cache_size = sizeof diskcache;
+    dev.cache_size = 128*1024;
+    dev.cache_data = malloc(dev.cache_size);
 
     return &dev;
 }
diff --git a/core/fs/fs.c b/core/fs/fs.c
index 2c10fe95..1cb4b00a 100644
--- a/core/fs/fs.c
+++ b/core/fs/fs.c
@@ -3,6 +3,7 @@
 #include <stdbool.h>
 #include <string.h>
 #include <unistd.h>
+#include <fcntl.h>
 #include <dprintf.h>
 #include "core.h"
 #include "dev.h"
@@ -138,7 +139,7 @@ size_t pmapi_read_file(uint16_t *handle, void *buf, size_t sectors)
     return bytes_read;
 }
 
-int searchdir(const char *name)
+int searchdir(const char *name, int flags)
 {
     static char root_name[] = "/";
     struct file *file;
@@ -155,7 +156,7 @@ int searchdir(const char *name)
 
     /* if we have ->searchdir method, call it */
     if (file->fs->fs_ops->searchdir) {
-	file->fs->fs_ops->searchdir(name, file);
+	file->fs->fs_ops->searchdir(name, flags, file);
 
 	if (file->inode)
 	    return file_to_handle(file);
@@ -336,7 +337,7 @@ err_no_close:
     return -1;
 }
 
-__export int open_file(const char *name, struct com32_filedata *filedata)
+__export int open_file(const char *name, int flags, struct com32_filedata *filedata)
 {
     int rv;
     struct file *file;
@@ -345,7 +346,7 @@ __export int open_file(const char *name, struct com32_filedata *filedata)
     dprintf("open_file %s\n", name);
 
     mangle_name(mangled_name, name);
-    rv = searchdir(mangled_name);
+    rv = searchdir(mangled_name, flags);
 
     if (rv < 0)
 	return rv;
@@ -399,9 +400,6 @@ void fs_init(com32sys_t *regs)
     /* ops is a ptr list for several fs_ops */
     const struct fs_ops **ops = (const struct fs_ops **)regs->eax.l;
 
-    /* Initialize malloc() */
-    mem_init();
-
     /* Default name for the root directory */
     fs.cwd_name[0] = '/';
 
diff --git a/core/fs/lib/searchconfig.c b/core/fs/lib/searchconfig.c
index b2a964e8..bb1dabf9 100644
--- a/core/fs/lib/searchconfig.c
+++ b/core/fs/lib/searchconfig.c
@@ -1,4 +1,5 @@
 #include <dprintf.h>
+#include <fcntl.h>
 #include <stdio.h>
 #include <string.h>
 #include <core.h>
@@ -30,7 +31,7 @@ int search_dirs(struct com32_filedata *filedata,
 	    if (realpath(realname, namebuf, FILENAME_MAX) == (size_t)-1)
 		continue;
 	    dprintf("Config search: %s\n", realname);
-	    if (open_file(realname, filedata) >= 0) {
+	    if (open_file(realname, O_RDONLY, filedata) >= 0) {
 		chdir(sd);
 		return 0;	/* Got it */
 	    }
diff --git a/core/fs/pxe/core.c b/core/fs/pxe/core.c
new file mode 100644
index 00000000..9246f669
--- /dev/null
+++ b/core/fs/pxe/core.c
@@ -0,0 +1,207 @@
+#include <syslinux/pxe_api.h>
+#include <lwip/api.h>
+#include <lwip/tcpip.h>
+#include <lwip/dns.h>
+#include <core.h>
+#include <net.h>
+#include "pxe.h"
+
+/**
+ * Open a socket
+ *
+ * @param:socket, the socket to open
+ * @param:proto, the protocol of the new connection
+ *
+ * @out: error code, 0 on success, -1 on failure
+ */
+int net_core_open(struct pxe_pvt_inode *socket, enum net_core_proto proto)
+{
+    struct net_private *priv = &socket->private;
+    enum netconn_type type;
+    int err;
+
+    switch (proto) {
+    case NET_CORE_TCP:
+	type = NETCONN_TCP;
+	break;
+    case NET_CORE_UDP:
+	type = NETCONN_UDP;
+	break;
+    default:
+	type = NETCONN_INVALID;
+	break;
+    }
+
+    priv->conn = netconn_new(type);
+    if (!priv->conn)
+	return -1;
+
+    priv->conn->recv_timeout = 15; /* A 15 ms recv timeout... */
+    err = netconn_bind(priv->conn, NULL, 0);
+    if (err) {
+	printf("netconn_bind error %d\n", err);
+	return -1;
+    }
+
+    return 0;
+}
+
+/**
+ * Close a socket
+ *
+ * @param:socket, the socket to open
+ */
+void net_core_close(struct pxe_pvt_inode *socket)
+{
+    struct net_private *priv = &socket->private;
+
+    if (priv->conn) {
+	netconn_delete(priv->conn);
+	priv->conn = NULL;
+    }
+}
+
+/**
+ * Establish a connection on an open socket
+ *
+ * @param:socket, the open socket
+ * @param:ip, the ip address
+ * @param:port, the port number, host-byte order
+ */
+void net_core_connect(struct pxe_pvt_inode *socket, uint32_t ip,
+		      uint16_t port)
+{
+    struct net_private *priv = &socket->private;
+    struct ip_addr addr;
+
+    addr.addr = ip;
+    netconn_connect(priv->conn, &addr, port);
+}
+
+/**
+ * Tear down a connection on an open socket
+ *
+ * @param:socket, the open socket
+ */
+void net_core_disconnect(struct pxe_pvt_inode *socket)
+{
+    struct net_private *priv = &socket->private;
+    netconn_disconnect(priv->conn);
+}
+
+/**
+ * Read data from the network stack
+ *
+ * @param:socket, the open socket
+ * @param:buf, location of buffer to store data
+ * @param:buf_len, size of buffer
+
+ * @out: src_ip, ip address of the data source
+ * @out: src_port, port number of the data source, host-byte order
+ */
+int net_core_recv(struct pxe_pvt_inode *socket, void *buf, uint16_t *buf_len,
+		  uint32_t *src_ip, uint16_t *src_port)
+{
+    struct net_private *priv = &socket->private;
+    struct netbuf *nbuf;
+    u16_t nbuf_len;
+    int err;
+
+    err = netconn_recv(priv->conn, &nbuf);
+    if (err)
+	return err;
+
+    if (!nbuf)
+	return -1;
+
+    *src_ip = netbuf_fromaddr(nbuf)->addr;
+    *src_port = netbuf_fromport(nbuf);
+
+    netbuf_first(nbuf);		/* XXX needed? */
+    nbuf_len = netbuf_len(nbuf);
+    if (nbuf_len <= *buf_len)
+	netbuf_copy(nbuf, buf, nbuf_len);
+    else
+	nbuf_len = 0; /* impossible mtu < PKTBUF_SIZE */
+    netbuf_delete(nbuf);
+
+    *buf_len = nbuf_len;
+    return 0;
+}
+
+/**
+ * Send a UDP packet.
+ *
+ * @param:socket, the open socket
+ * @param:data, data buffer to send
+ * @param:len, size of data bufer
+ */
+void net_core_send(struct pxe_pvt_inode *socket, const void *data, size_t len)
+{
+    struct netconn *conn = socket->private.conn;
+    struct netbuf *nbuf;
+    void *pbuf;
+    int err;
+
+    nbuf = netbuf_new();
+    if (!nbuf) {
+	printf("netbuf allocation error\n");
+	return;
+    }
+
+    pbuf = netbuf_alloc(nbuf, len);
+    if (!pbuf) {
+	printf("pbuf allocation error\n");
+	goto out;
+    }
+
+    memcpy(pbuf, data, len);
+
+    err = netconn_send(conn, nbuf);
+    if (err) {
+	printf("netconn_send error %d\n", err);
+	goto out;
+    }
+
+out:
+    netbuf_delete(nbuf);
+}
+
+/**
+ * Network stack-specific initialization
+ */
+void net_core_init(void)
+{
+    int err;
+    int i;
+
+    http_bake_cookies();
+
+    /* Initialize lwip */
+    tcpip_init(NULL, NULL);
+
+    /* Start up the undi driver for lwip */
+    err = undiif_start(IPInfo.myip, IPInfo.netmask, IPInfo.gateway);
+    if (err) {
+       printf("undiif driver failed to start: %d\n", err);
+       kaboom();
+    }
+
+    for (i = 0; i < DNS_MAX_SERVERS; i++) {
+	/* Transfer the DNS information to lwip */
+	dns_setserver(i, (struct ip_addr *)&dns_server[i]);
+    }
+}
+
+void probe_undi(void)
+{
+    /* Probe UNDI information */
+    pxe_call(PXENV_UNDI_GET_INFORMATION, &pxe_undi_info);
+    pxe_call(PXENV_UNDI_GET_IFACE_INFO,  &pxe_undi_iface);
+
+    printf("UNDI: baseio %04x int %d MTU %d type %d \"%s\" flags 0x%x\n",
+	   pxe_undi_info.BaseIo, pxe_undi_info.IntNumber,
+	   pxe_undi_info.MaxTranUnit, pxe_undi_info.HwType,
+	   pxe_undi_iface.IfaceType, pxe_undi_iface.ServiceFlags);
+}
+
diff --git a/core/fs/pxe/dhcp_option.c b/core/fs/pxe/dhcp_option.c
index f63d4a91..75827ff7 100644
--- a/core/fs/pxe/dhcp_option.c
+++ b/core/fs/pxe/dhcp_option.c
@@ -2,6 +2,7 @@
 #include <string.h>
 #include <core.h>
 #include <sys/cpu.h>
+#include <lwip/opt.h>		/* DNS_MAX_SERVERS */
 #include "pxe.h"
 
 char LocalDomain[256];
@@ -48,13 +49,8 @@ static void dns_servers(const void *data, int opt_len)
 
 static void local_domain(const void *data, int opt_len)
 {
-    char buffer[256];
-    char *ld = LocalDomain;
-
-    memcpy(buffer, data, opt_len);
-    buffer[opt_len] = 0;
-
-    dns_mangle(&ld, buffer);
+    memcpy(LocalDomain, data, opt_len);
+    LocalDomain[opt_len] = 0;
 }
 
 static void vendor_encaps(const void *data, int opt_len)
diff --git a/core/fs/pxe/dnsresolv.c b/core/fs/pxe/dnsresolv.c
index 184bacbd..afb9e219 100644
--- a/core/fs/pxe/dnsresolv.c
+++ b/core/fs/pxe/dnsresolv.c
@@ -2,6 +2,8 @@
 #include <string.h>
 #include <core.h>
 #include "pxe.h"
+#include "lwip/api.h"
+#include "lwip/dns.h"
 
 /* DNS CLASS values we care about */
 #define CLASS_IN	1
@@ -48,295 +50,82 @@ struct dnsrr {
 
 uint32_t dns_server[DNS_MAX_SERVERS] = {0, };
 
-
-/*
- * Turn a string in _src_ into a DNS "label set" in _dst_; returns the
- * number of dots encountered. On return, *dst is updated.
- */
-int dns_mangle(char **dst, const char *p)
-{
-    char *q = *dst;
-    char *count_ptr;
-    char c;
-    int dots = 0;
-
-    count_ptr = q;
-    *q++ = 0;
-
-    while (1) {
-        c = *p++;
-        if (c == 0 || c == ':' || c == '/')
-            break;
-        if (c == '.') {
-            dots++;
-            count_ptr = q;
-            *q++ = 0;
-            continue;
-        }
-
-        *count_ptr += 1;
-        *q++ = c;
-    }
-
-    if (*count_ptr)
-        *q++ = 0;
-
-    /* update the strings */
-    *dst = q;
-    return dots;
-}
-
-
 /*
- * Compare two sets of DNS labels, in _s1_ and _s2_; the one in _s2_
- * is allowed pointers relative to a packet in buf.
+ * parse the ip_str and return the ip address with *res.
+ * return true if the whole string was consumed and the result
+ * was valid.
  *
  */
-static bool dns_compare(const void *s1, const void *s2, const void *buf)
+static bool parse_dotquad(const char *ip_str, uint32_t *res)
 {
-    const uint8_t *q = s1;
-    const uint8_t *p = s2;
-    unsigned int c0, c1;
-
-    while (1) {
-	c0 = p[0];
-        if (c0 >= 0xc0) {
-	    /* Follow pointer */
-	    c1 = p[1];
-	    p = (const uint8_t *)buf + ((c0 - 0xc0) << 8) + c1;
-	} else if (c0) {
-	    c0++;		/* Include the length byte */
-	    if (memcmp(q, p, c0))
-		return false;
-	    q += c0;
-	    p += c0;
-	} else {
-	    return *q == 0;
-	}
-    }
-}
-
-/*
- * Copy a DNS label into a buffer, considering the possibility that we might
- * have to follow pointers relative to "buf".
- * Returns a pointer to the first free byte *after* the terminal null.
- */
-static void *dns_copylabel(void *dst, const void *src, const void *buf)
-{
-    uint8_t *q = dst;
-    const uint8_t *p = src;
-    unsigned int c0, c1;
+    const char *p = ip_str;
+    uint8_t part = 0;
+    uint32_t ip = 0;
+    int i;
+
+    for (i = 0; i < 4; i++) {
+        while (is_digit(*p)) {
+            part = part * 10 + *p - '0';
+            p++;
+        }
+        if (i != 3 && *p != '.')
+            return false;
 
-    while (1) {
-	c0 = p[0];
-        if (c0 >= 0xc0) {
-	    /* Follow pointer */
-	    c1 = p[1];
-	    p = (const uint8_t *)buf + ((c0 - 0xc0) << 8) + c1;
-	} else if (c0) {
-	    c0++;		/* Include the length byte */
-	    memcpy(q, p, c0);
-	    p += c0;
-	    q += c0;
-	} else {
-	    *q++ = 0;
-	    return q;
-	}
+        ip = (ip << 8) | part;
+        part = 0;
+        p++;
     }
-}
-
-/*
- * Skip past a DNS label set in DS:SI
- */
-static char *dns_skiplabel(char *label)
-{
-    uint8_t c;
+    p--;
 
-    while (1) {
-        c = *label++;
-        if (c >= 0xc0)
-            return ++label; /* pointer is two bytes */
-        if (c == 0)
-            return label;
-        label += c;
-    }
+    *res = htonl(ip);
+    return *p == '\0';
 }
 
 /*
- * Actual resolver function
- * Points to a null-terminated or :-terminated string in _name_
- * and returns the ip addr in _ip_ if it exists and can be found.
- * If _ip_ = 0 on exit, the lookup failed. _name_ will be updated
+ * Actual resolver function.
  *
- * XXX: probably need some caching here.
+ * Points to a null-terminated in _name_ and returns the ip addr in
+ * _ip_ if it exists and can be found.  If _ip_ = 0 on exit, the
+ * lookup failed. _name_ will be updated
  */
 __export uint32_t dns_resolv(const char *name)
 {
-    static char __lowmem DNSSendBuf[PKTBUF_SIZE];
-    static char __lowmem DNSRecvBuf[PKTBUF_SIZE];
-    char *p;
-    int err;
-    int dots;
-    int same;
-    int rd_len;
-    int ques, reps;    /* number of questions and replies */
-    uint8_t timeout;
-    const uint8_t *timeout_ptr = TimeoutTable;
-    uint32_t oldtime;
-    uint32_t srv;
-    uint32_t *srv_ptr;
-    struct dnshdr *hd1 = (struct dnshdr *)DNSSendBuf;
-    struct dnshdr *hd2 = (struct dnshdr *)DNSRecvBuf;
-    struct dnsquery *query;
-    struct dnsrr *rr;
-    static __lowmem struct s_PXENV_UDP_WRITE udp_write;
-    static __lowmem struct s_PXENV_UDP_READ  udp_read;
-    uint16_t local_port;
-    uint32_t result = 0;
-
-    /* Make sure we have at least one valid DNS server */
-    if (!dns_server[0])
+    err_t err;
+    struct ip_addr ip;
+    char fullname[512];
+
+    /*
+     * Return failure on an empty input... this can happen during
+     * some types of URL parsing, and this is the easiest place to
+     * check for it.
+     */
+    if (!name || !*name)
 	return 0;
 
-    /* Get a local port number */
-    local_port = get_port();
-
-    /* First, fill the DNS header struct */
-    hd1->id++;                      /* New query ID */
-    hd1->flags   = htons(0x0100);   /* Recursion requested */
-    hd1->qdcount = htons(1);        /* One question */
-    hd1->ancount = 0;               /* No answers */
-    hd1->nscount = 0;               /* No NS */
-    hd1->arcount = 0;               /* No AR */
-
-    p = DNSSendBuf + sizeof(struct dnshdr);
-    dots = dns_mangle(&p, name);   /* store the CNAME */
-
-    if (!dots) {
-        p--; /* Remove final null */
-        /* Uncompressed DNS label set so it ends in null */
-        p = stpcpy(p, LocalDomain);
-    }
-
-    /* Fill the DNS query packet */
-    query = (struct dnsquery *)p;
-    query->qtype  = htons(TYPE_A);
-    query->qclass = htons(CLASS_IN);
-    p += sizeof(struct dnsquery);
-
-    /* Now send it to name server */
-    timeout_ptr = TimeoutTable;
-    timeout = *timeout_ptr++;
-    srv_ptr = dns_server;
-    while (timeout) {
-	srv = *srv_ptr++;
-	if (!srv) {
-	    srv_ptr = dns_server;
-	    srv = *srv_ptr++;
-	}
-
-        udp_write.status      = 0;
-        udp_write.ip          = srv;
-        udp_write.gw          = gateway(srv);
-        udp_write.src_port    = local_port;
-        udp_write.dst_port    = DNS_PORT;
-        udp_write.buffer_size = p - DNSSendBuf;
-        udp_write.buffer      = FAR_PTR(DNSSendBuf);
-        err = pxe_call(PXENV_UDP_WRITE, &udp_write);
-        if (err || udp_write.status)
-            continue;
-
-        oldtime = jiffies();
-	do {
-	    if (jiffies() - oldtime >= timeout)
-		goto again;
-
-            udp_read.status      = 0;
-            udp_read.src_ip      = srv;
-            udp_read.dest_ip     = IPInfo.myip;
-            udp_read.s_port      = DNS_PORT;
-            udp_read.d_port      = local_port;
-            udp_read.buffer_size = PKTBUF_SIZE;
-            udp_read.buffer      = FAR_PTR(DNSRecvBuf);
-            err = pxe_call(PXENV_UDP_READ, &udp_read);
-	} while (err || udp_read.status || hd2->id != hd1->id);
+    /* If it is a valid dot quad, just return that value */
+    if (parse_dotquad(name, &ip.addr))
+	return ip.addr;
 
-        if ((hd2->flags ^ 0x80) & htons(0xf80f))
-            goto badness;
-
-        ques = htons(hd2->qdcount);   /* Questions */
-        reps = htons(hd2->ancount);   /* Replies   */
-        p = DNSRecvBuf + sizeof(struct dnshdr);
-        while (ques--) {
-            p = dns_skiplabel(p); /* Skip name */
-            p += 4;               /* Skip question trailer */
-        }
-
-        /* Parse the replies */
-        while (reps--) {
-            same = dns_compare(DNSSendBuf + sizeof(struct dnshdr),
-			       p, DNSRecvBuf);
-            p = dns_skiplabel(p);
-            rr = (struct dnsrr *)p;
-            rd_len = ntohs(rr->rdlength);
-            if (same && ntohs(rr->class) == CLASS_IN) {
-		switch (ntohs(rr->type)) {
-		case TYPE_A:
-		    if (rd_len == 4) {
-			result = *(uint32_t *)rr->rdata;
-			goto done;
-		    }
-		    break;
-		case TYPE_CNAME:
-		    dns_copylabel(DNSSendBuf + sizeof(struct dnshdr),
-				  rr->rdata, DNSRecvBuf);
-		    /*
-		     * We should probably rescan the packet from the top
-		     * here, and technically we might have to send a whole
-		     * new request here...
-		     */
-		    break;
-		default:
-		    break;
-		}
-	    }
-
-            /* not the one we want, try next */
-            p += sizeof(struct dnsrr) + rd_len;
-        }
-
-    badness:
-        /*
-         *
-         ; We got back no data from this server.
-         ; Unfortunately, for a recursive, non-authoritative
-         ; query there is no such thing as an NXDOMAIN reply,
-         ; which technically means we can't draw any
-         ; conclusions.  However, in practice that means the
-         ; domain doesn't exist.  If this turns out to be a
-         ; problem, we may want to add code to go through all
-         ; the servers before giving up.
-
-         ; If the DNS server wasn't capable of recursion, and
-         ; isn't capable of giving us an authoritative reply
-         ; (i.e. neither AA or RA set), then at least try a
-         ; different setver...
-        */
-        if (hd2->flags == htons(0x480))
-            continue;
-
-        break; /* failed */
+    /* Make sure we have at least one valid DNS server */
+    if (!dns_getserver(0).addr)
+	return 0;
 
-    again:
-	continue;
+    /* Is it a local (unqualified) domain name? */
+    if (!strchr(name, '.') && LocalDomain[0]) {
+	snprintf(fullname, sizeof fullname, "%s.%s", name, LocalDomain);
+	name = fullname;
     }
 
-done:
-    free_port(local_port);	/* Return port number to the free pool */
+    err = netconn_gethostbyname(name, &ip);
+    if (err)
+	return 0;
 
-    return result;
+    return ip.addr;
 }
 
+/*
+ * the one should be called from ASM file
+ */
 void pm_pxe_dns_resolv(com32sys_t *regs)
 {
     const char *name = MK_PTR(regs->ds, regs->esi.w[0]);
diff --git a/core/fs/pxe/ftp.c b/core/fs/pxe/ftp.c
new file mode 100644
index 00000000..5d5a6f03
--- /dev/null
+++ b/core/fs/pxe/ftp.c
@@ -0,0 +1,280 @@
+/* ----------------------------------------------------------------------- *
+ *   
+ *   Copyright 2009-2011 Intel Corporation; author: H. Peter Anvin
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ *   Boston MA 02110-1301, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * ftp.c
+ */
+#include <ctype.h>
+#include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
+#include <minmax.h>
+#include <sys/cpu.h>
+#include <netinet/in.h>
+#include <lwip/api.h>
+#include "core.h"
+#include "fs.h"
+#include "pxe.h"
+#include "thread.h"
+#include "url.h"
+
+static int ftp_cmd_response(struct inode *inode, const char *cmd,
+			    const char *cmd_arg,
+			    uint8_t *pasv_data, int *pn_ptr)
+{
+    struct pxe_pvt_inode *socket = PVT(inode);
+    int c;
+    int pos, code;
+    int pb, pn;
+    bool ps;
+    bool first_line, done;
+    err_t err;
+    char cmd_buf[4096];
+    int cmd_len;
+    const char *p;
+    char *q;
+
+    if (cmd) {
+	cmd_len = strlcpy(cmd_buf, cmd, sizeof cmd_buf);
+	if (cmd_len >= sizeof cmd_buf - 3)
+	    return -1;
+	q = cmd_buf + cmd_len;
+
+	if (cmd_arg) {
+	    p = cmd_arg;
+
+	    *q++ = ' ';
+	    cmd_len++;
+	    while (*p) {
+		if (++cmd_len < sizeof cmd_buf) *q++ = *p;
+		if (*p == '\r')
+		    if (++cmd_len < sizeof cmd_buf) *q++ = '\0';
+		p++;
+	    }
+
+	    if (cmd_len >= sizeof cmd_buf - 2)
+		return -1;
+	}
+
+	*q++ = '\r';
+	*q++ = '\n';
+	cmd_len += 2;
+
+	err = netconn_write(socket->private.conn, cmd_buf, cmd_len, NETCONN_COPY);
+	if (err)
+	    return -1;
+    }
+
+    pos = code = pn = pb = 0;
+    ps = false;
+    first_line = true;
+    done = false;
+
+    while ((c = pxe_getc(inode)) >= 0) {
+	if (c == '\n') {
+	    if (done) {
+		if (pn) {
+		    pn += ps;
+		    if (pn_ptr)
+			*pn_ptr = pn;
+		}
+		return code;
+	    }
+	    pos = code = 0;
+	    first_line = false;
+	    continue;
+	}
+
+	switch (pos++) {
+	case 0:
+	case 1:
+	case 2:
+	    if (c < '0' || c > '9') {
+		if (first_line)
+		    return -1;
+		else
+		    pos = 4;	/* Skip this line */
+	    } else {
+		code = (code*10) + (c - '0');
+	    }
+	    break;
+
+	case 3:
+	    pn = pb = 0;
+	    ps = false;
+	    if (c == ' ')
+		done = true;
+	    else if (c == '-')
+		done = false;
+	    else if (first_line)
+		return -1;
+	    else
+		done = false;
+	    break;
+
+	default:
+	    if (pasv_data) {
+		if (c >= '0' && c <= '9') {
+		    pb = (pb*10) + (c-'0');
+		    if (pn < 6)
+			pasv_data[pn] = pb;
+		    ps = true;
+		} else if (c == ',') {
+		    pn++;
+		    pb = 0;
+		    ps = false;
+		} else if (pn) {
+		    pn += ps;
+		    if (pn_ptr)
+			*pn_ptr = pn;
+		    pn = pb = 0;
+		    ps = false;
+		}
+	    }
+	    break;
+	}
+    }
+
+    return -1;
+}
+
+static void ftp_free(struct inode *inode)
+{
+    struct pxe_pvt_inode *socket = PVT(inode);
+
+    if (socket->ctl) {
+	tcp_close_file(socket->ctl);
+	free_socket(socket->ctl);
+	socket->ctl = NULL;
+    }
+    tcp_close_file(inode);
+}
+
+static void ftp_close_file(struct inode *inode)
+{
+    struct pxe_pvt_inode *socket  = PVT(inode);
+    struct pxe_pvt_inode *ctlsock;
+    int resp;
+
+    ctlsock = socket->ctl ? PVT(socket->ctl) : NULL;
+    if (ctlsock->private.conn) {
+	resp = ftp_cmd_response(socket->ctl, "QUIT", NULL, NULL, NULL);
+	while (resp == 226) {
+	    resp = ftp_cmd_response(socket->ctl, NULL, NULL, NULL, NULL);
+	}
+    }
+    ftp_free(inode);
+}
+
+static const struct pxe_conn_ops ftp_conn_ops = {
+    .fill_buffer	= tcp_fill_buffer,
+    .close		= ftp_close_file,
+    .readdir		= ftp_readdir,
+};
+
+void ftp_open(struct url_info *url, int flags, struct inode *inode,
+	      const char **redir)
+{
+    struct pxe_pvt_inode *socket = PVT(inode);
+    struct pxe_pvt_inode *ctlsock;
+    struct ip_addr addr;
+    uint8_t pasv_data[6];
+    int pasv_bytes;
+    int resp;
+    err_t err;
+
+    (void)redir;		/* FTP does not redirect */
+
+    inode->size = 0;
+
+    if (!url->port)
+	url->port = 21;
+
+    url_unescape(url->path, 0);
+
+    socket->ops = &ftp_conn_ops;
+
+    /* Set up the control connection */
+    socket->ctl = alloc_inode(inode->fs, 0, sizeof(struct pxe_pvt_inode));
+    if (!socket->ctl)
+	return;
+    ctlsock = PVT(socket->ctl);
+    ctlsock->ops = &tcp_conn_ops; /* The control connection is just TCP */
+    ctlsock->private.conn = netconn_new(NETCONN_TCP);
+    if (!ctlsock->private.conn)
+	goto err_free;
+    addr.addr = url->ip;
+    err = netconn_connect(ctlsock->private.conn, &addr, url->port);
+    if (err)
+	goto err_delete;
+
+    do {
+	resp = ftp_cmd_response(socket->ctl, NULL, NULL, NULL, NULL);
+    } while (resp == 120);
+    if (resp != 220)
+	goto err_disconnect;
+
+    if (!url->user)
+	url->user = "anonymous";
+    if (!url->passwd)
+	url->passwd = "syslinux@";
+
+    resp = ftp_cmd_response(socket->ctl, "USER", url->user, NULL, NULL);
+    if (resp != 202 && resp != 230) {
+	if (resp != 331)
+	    goto err_disconnect;
+
+	resp = ftp_cmd_response(socket->ctl, "PASS", url->passwd, NULL, NULL);
+	if (resp != 230)
+	    goto err_disconnect;
+    }
+
+    if (!(flags & O_DIRECTORY)) {
+	resp = ftp_cmd_response(socket->ctl, "TYPE", "I", NULL, NULL);
+	if (resp != 200)
+	    goto err_disconnect;
+    }
+
+    resp = ftp_cmd_response(socket->ctl, "PASV", NULL, pasv_data, &pasv_bytes);
+    if (resp != 227 || pasv_bytes != 6)
+	goto err_disconnect;
+
+    socket->private.conn = netconn_new(NETCONN_TCP);
+    if (!socket->private.conn)
+	goto err_disconnect;
+    err = netconn_connect(socket->private.conn, (struct ip_addr *)&pasv_data[0],
+			  ntohs(*(uint16_t *)&pasv_data[4]));
+    if (err)
+	goto err_disconnect;
+
+    resp = ftp_cmd_response(socket->ctl,
+			    (flags & O_DIRECTORY) ? "LIST" : "RETR",
+			    url->path, NULL, NULL);
+    if (resp != 125 && resp != 150)
+	goto err_disconnect;
+
+    inode->size = -1;
+    return;			/* Sucess! */
+
+err_disconnect:
+    if (ctlsock->private.conn)
+	netconn_write(ctlsock->private.conn, "QUIT\r\n", 6, NETCONN_NOCOPY);
+    if (socket->private.conn)
+	netconn_delete(socket->private.conn);
+    if (ctlsock->private.buf)
+	netbuf_delete(ctlsock->private.buf);
+err_delete:
+    if (ctlsock->private.conn)
+	netconn_delete(ctlsock->private.conn);
+err_free:
+    free_socket(socket->ctl);
+}
diff --git a/core/fs/pxe/ftp_readdir.c b/core/fs/pxe/ftp_readdir.c
new file mode 100644
index 00000000..6b87f77e
--- /dev/null
+++ b/core/fs/pxe/ftp_readdir.c
@@ -0,0 +1,141 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2011 Intel Corporation; author: H. Peter Anvin
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ *   Boston MA 02110-1301, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * ftp_readdir.c
+ */
+#include <inttypes.h>
+#include <string.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <dprintf.h>
+#include "pxe.h"
+
+static int dirtype(char type)
+{
+    switch (type) {
+    case 'f':
+	return DT_FIFO;
+    case 'c':
+	return DT_CHR;
+    case 'd':
+	return DT_DIR;
+    case 'b':
+	return DT_BLK;
+    case '-':
+    case '0' ... '9':		/* Some DOS FTP stacks */
+	return DT_REG;
+    case 'l':
+	return DT_LNK;
+    case 's':
+	return DT_SOCK;
+    default:
+	return DT_UNKNOWN;
+    }
+}
+
+int ftp_readdir(struct inode *inode, struct dirent *dirent)
+{
+    char bufs[2][FILENAME_MAX + 1];
+    int nbuf = 0;
+    char *buf = bufs[nbuf];
+    char *p = buf;
+    char *name = NULL;
+    char type;
+    int c;
+    int dt;
+    bool was_cr = false;
+    bool first = true;
+
+    for (;;) {
+	type = 0;
+
+	for (;;) {
+	    c = pxe_getc(inode);
+	    if (c == -1)
+		return -1;	/* Nothing else there */
+
+	    if (c == '\r') {
+		was_cr = true;
+		continue;
+	    }
+	    if (was_cr) {
+		if (c == '\n') {
+		    if (!name) {
+			*p = '\0';
+			name = buf;
+		    }
+		    break;	/* End of line */
+		}
+		else if (c == '\0')
+		    c = '\r';
+	    }
+	    was_cr = false;
+
+	    if (c == ' ' || c == '\t') {
+		if (!name) {
+		    *p = '\0';
+		    if (first) {
+			if (p == buf) {
+			    /* Name started with whitespace - skip line */
+			    name = buf;
+			} else if ((p = strchr(buf, ';'))) {
+			    /* VMS/Multinet format */
+			    if (p > buf+4 && !memcmp(p-4, ".DIR", 4)) {
+				type = 'd';
+				p -= 4;
+			    } else {
+				type = 'f';
+			    }
+			    *p = '\0';
+			    name = buf;
+			} else {
+			    type = buf[0];
+			}
+			first = false;
+		    } else {
+			/* Not the first word */
+			if ((type >= '0' && type <= '9') &&
+			    !strcmp(buf, "<DIR>")) {
+			    /* Some DOS FTP servers */
+			    type = 'd';
+			} else if (type == 'l' && !strcmp(buf, "->")) {
+			    /* The name was the previous word */
+			    name = bufs[nbuf ^ 1];
+			}
+		    }
+		    nbuf ^= 1;
+		    p = buf = bufs[nbuf];
+		}
+	    } else {
+		if (!name && p < buf + FILENAME_MAX)
+		    *p++ = c;
+	    }
+	}
+
+	dt = dirtype(type);
+	if (dt != DT_UNKNOWN) {
+	    size_t len = strlen(name);
+
+	    if (len <= NAME_MAX) {
+		dirent->d_type = dt;
+		dirent->d_ino = 0;	/* Not applicable */
+		dirent->d_off = 0;	/* Not applicable */
+		dirent->d_reclen = offsetof(struct dirent, d_name) + len+1;
+		memcpy(dirent->d_name, name, len+1);
+		return 0;
+	    }
+	}
+
+	/* Otherwise try the next line... */
+    }
+}
diff --git a/core/fs/pxe/gpxeurl.c b/core/fs/pxe/gpxeurl.c
new file mode 100644
index 00000000..6bbae3c2
--- /dev/null
+++ b/core/fs/pxe/gpxeurl.c
@@ -0,0 +1,88 @@
+#include "pxe.h"
+#if GPXE
+
+static void gpxe_close_file(struct inode *inode)
+{
+    struct pxe_pvt_inode *socket = PVT(inode);
+    static __lowmem struct s_PXENV_FILE_CLOSE file_close;
+
+    file_close.FileHandle = socket->tftp_remoteport;
+    pxe_call(PXENV_FILE_CLOSE, &file_close);
+}
+
+/**
+ * Get a fresh packet from a gPXE socket
+ * @param: inode -> Inode pointer
+ *
+ */
+static void gpxe_get_packet(struct inode *inode)
+{
+    struct pxe_pvt_inode *socket = PVT(inode);
+    static __lowmem struct s_PXENV_FILE_READ file_read;
+    int err;
+
+    while (1) {
+        file_read.FileHandle  = socket->tftp_remoteport;
+        file_read.Buffer      = FAR_PTR(packet_buf);
+        file_read.BufferSize  = PKTBUF_SIZE;
+        err = pxe_call(PXENV_FILE_READ, &file_read);
+        if (!err)  /* successed */
+            break;
+
+        if (file_read.Status != PXENV_STATUS_TFTP_OPEN)
+	    kaboom();
+    }
+
+    memcpy(socket->tftp_pktbuf, packet_buf, file_read.BufferSize);
+
+    socket->tftp_dataptr   = socket->tftp_pktbuf;
+    socket->tftp_bytesleft = file_read.BufferSize;
+    socket->tftp_filepos  += file_read.BufferSize;
+
+    if (socket->tftp_bytesleft == 0)
+        inode->size = socket->tftp_filepos;
+
+    /* if we're done here, close the file */
+    if (inode->size > socket->tftp_filepos)
+        return;
+
+    /* Got EOF, close it */
+    socket->tftp_goteof = 1;
+    gpxe_close_file(inode);
+}
+
+/**
+ * Open a url using gpxe
+ *
+ * @param:inode, the inode to store our state in
+ * @param:url, the url we want to open
+ *
+ * @out: open_file_t structure, stores in file->open_file
+ * @out: the lenght of this file, stores in file->file_len
+ *
+ */
+void gpxe_open(struct inode *inode, const char *url)
+{
+    static __lowmem struct s_PXENV_FILE_OPEN file_open;
+    static char lowurl[2*FILENAME_MAX];
+    struct pxe_pvt_inode *socket = PVT(inode);
+    int err;
+
+    socket->tftp_pktbuf = malloc(PKTBUF_SIZE);
+    if (!socket->tftp_pktbuf)
+	return;
+
+    snprintf(lowurl, sizeof lowurl, "%s", url);
+    file_open.Status        = PXENV_STATUS_BAD_FUNC;
+    file_open.FileName      = FAR_PTR(lowurl);
+    err = pxe_call(PXENV_FILE_OPEN, &file_open);
+    if (err)
+	return; 
+
+    socket->fill_buffer = gpxe_get_packet;
+    socket->close = gpxe_close_file;
+    socket->tftp_remoteport = file_open.FileHandle;
+    inode->size = -1; /* This is not an error */
+}
+
+#endif /* GPXE */
diff --git a/core/fs/pxe/http.c b/core/fs/pxe/http.c
new file mode 100644
index 00000000..9bf0c92e
--- /dev/null
+++ b/core/fs/pxe/http.c
@@ -0,0 +1,400 @@
+#include <syslinux/sysappend.h>
+#include <ctype.h>
+#include <lwip/api.h>
+#include "pxe.h"
+#include "../../../version.h"
+#include "url.h"
+
+#define HTTP_PORT	80
+
+static bool is_tspecial(int ch)
+{
+    bool tspecial = false;
+    switch(ch) {
+    case '(':  case ')':  case '<':  case '>':  case '@':
+    case ',':  case ';':  case ':':  case '\\': case '"':
+    case '/':  case '[':  case ']':  case '?':  case '=':
+    case '{':  case '}':  case ' ':  case '\t':
+	tspecial = true;
+	break;
+    }
+    return tspecial;
+}
+
+static bool is_ctl(int ch)
+{
+    return ch < 0x20;
+}
+
+static bool is_token(int ch)
+{
+    /* Can by antying except a ctl character or a tspecial */
+    return !is_ctl(ch) && !is_tspecial(ch);
+}
+
+static bool append_ch(char *str, size_t size, size_t *pos, int ch)
+{
+    bool success = true;
+    if ((*pos + 1) >= size) {
+	*pos = 0;
+	success = false;
+    } else {
+	str[*pos] = ch;
+	str[*pos + 1] = '\0';
+	*pos += 1;
+    }
+    return success;
+}
+
+static size_t cookie_len, header_len;
+static char *cookie_buf, *header_buf;
+
+__export uint32_t SendCookies = -1UL; /* Send all cookies */
+
+static size_t http_do_bake_cookies(char *q)
+{
+    static const char uchexchar[16] = "0123456789ABCDEF";
+    int i;
+    size_t n = 0;
+    const char *p;
+    char c;
+    bool first = true;
+    uint32_t mask = SendCookies;
+
+    for (i = 0; i < SYSAPPEND_MAX; i++) {
+	if ((mask & 1) && (p = sysappend_strings[i])) {
+	    if (first) {
+		if (q) {
+		    strcpy(q, "Cookie: ");
+		    q += 8;
+		}
+		n += 8;
+		first = false;
+	    }
+	    if (q) {
+		strcpy(q, "_Syslinux_");
+		q += 10;
+	    }
+	    n += 10;
+	    /* Copy string up to and including '=' */
+	    do {
+		c = *p++;
+		if (q)
+		    *q++ = c;
+		n++;
+	    } while (c != '=');
+	    while ((c = *p++)) {
+		if (c == ' ') {
+		    if (q)
+			*q++ = '+';
+		    n++;
+		} else if (is_token(c)) {
+		    if (q)
+			*q++ = c;
+		    n++;
+		} else {
+		    if (q) {
+			*q++ = '%';
+			*q++ = uchexchar[c >> 4];
+			*q++ = uchexchar[c & 15];
+		    }
+		    n += 3;
+		}
+	    }
+	    if (q)
+		*q++ = ';';
+	    n++;
+	}
+	mask >>= 1;
+    }
+    if (!first) {
+	if (q) {
+	    *q++ = '\r';
+	    *q++ = '\n';
+	}
+	n += 2;
+    }
+    if (q)
+	*q = '\0';
+    
+    return n;
+}
+
+void http_bake_cookies(void)
+{
+    if (cookie_buf)
+	free(cookie_buf);
+
+    cookie_len = http_do_bake_cookies(NULL);
+    cookie_buf = malloc(cookie_len+1);
+    if (!cookie_buf) {
+	cookie_len = 0;
+	return;
+    }
+
+    if (header_buf)
+	free(header_buf);
+
+    header_len = cookie_len + 6*FILENAME_MAX + 256;
+    header_buf = malloc(header_len);
+    if (!header_buf) {
+	header_len = 0;
+	return;			/* Uh-oh... */
+    }
+
+    http_do_bake_cookies(cookie_buf);
+}
+
+static const struct pxe_conn_ops http_conn_ops = {
+    .fill_buffer	= tcp_fill_buffer,
+    .close		= tcp_close_file,
+    .readdir		= http_readdir,
+};
+
+void http_open(struct url_info *url, int flags, struct inode *inode,
+	       const char **redir)
+{
+    struct pxe_pvt_inode *socket = PVT(inode);
+    int header_bytes;
+    const char *next;
+    char field_name[20];
+    char field_value[1024];
+    size_t field_name_len, field_value_len;
+    err_t err;
+    enum state {
+	st_httpver,
+	st_stcode,
+	st_skipline,
+	st_fieldfirst,
+	st_fieldname,
+	st_fieldvalue,
+	st_skip_fieldname,
+	st_skip_fieldvalue,
+	st_eoh,
+    } state;
+    struct ip_addr addr;
+    static char location[FILENAME_MAX];
+    uint32_t content_length; /* same as inode->size */
+    size_t response_size;
+    int status;
+    int pos;
+
+    (void)flags;
+
+    if (!header_buf)
+	return;			/* http is broken... */
+
+    /* This is a straightforward TCP connection after headers */
+    socket->ops = &http_conn_ops;
+
+    /* Reset all of the variables */
+    inode->size = content_length = -1;
+
+    /* Start the http connection */
+    socket->private.conn = netconn_new(NETCONN_TCP);
+    if (!socket->private.conn) {
+	printf("netconn_new failed\n");
+        return;
+    }
+
+    addr.addr = url->ip;
+    if (!url->port)
+	url->port = HTTP_PORT;
+
+    err = netconn_connect(socket->private.conn, &addr, url->port);
+    if (err) {
+	printf("netconn_connect error %d\n", err);
+	goto fail;
+    }
+
+    strcpy(header_buf, "GET /");
+    header_bytes = 5;
+    header_bytes += url_escape_unsafe(header_buf+5, url->path,
+				      header_len - 5);
+    if (header_bytes >= header_len)
+	goto fail;		/* Buffer overflow */
+    header_bytes += snprintf(header_buf + header_bytes,
+			     header_len - header_bytes,
+			     " HTTP/1.0\r\n"
+			     "Host: %s\r\n"
+			     "User-Agent: Syslinux/" VERSION_STR "\r\n"
+			     "Connection: close\r\n"
+			     "%s"
+			     "\r\n",
+			     url->host, cookie_buf ? cookie_buf : "");
+    if (header_bytes >= header_len)
+	goto fail;		/* Buffer overflow */
+
+    err = netconn_write(socket->private.conn, header_buf,
+			header_bytes, NETCONN_NOCOPY);
+    if (err) {
+	printf("netconn_write error %d\n", err);
+	goto fail;
+    }
+
+    /* Parse the HTTP header */
+    state = st_httpver;
+    pos = 0;
+    status = 0;
+    response_size = 0;
+    field_value_len = 0;
+    field_name_len = 0;
+
+    while (state != st_eoh) {
+	int ch = pxe_getc(inode);
+	/* Eof before I finish paring the header */
+	if (ch == -1)
+	    goto fail;
+#if 0
+        printf("%c", ch);
+#endif
+	response_size++;
+	if (ch == '\r' || ch == '\0')
+	    continue;
+	switch (state) {
+	case st_httpver:
+	    if (ch == ' ') {
+		state = st_stcode;
+		pos = 0;
+	    }
+	    break;
+
+	case st_stcode:
+	    if (ch < '0' || ch > '9')
+	       goto fail;
+	    status = (status*10) + (ch - '0');
+	    if (++pos == 3)
+		state = st_skipline;
+	    break;
+
+	case st_skipline:
+	    if (ch == '\n')
+		state = st_fieldfirst;
+	    break;
+
+	case st_fieldfirst:
+	    if (ch == '\n')
+		state = st_eoh;
+	    else if (isspace(ch)) {
+		/* A continuation line */
+		state = st_fieldvalue;
+		goto fieldvalue;
+	    }
+	    else if (is_token(ch)) {
+		/* Process the previous field before starting on the next one */
+		if (strcasecmp(field_name, "Content-Length") == 0) {
+		    next = field_value;
+		    /* Skip leading whitespace */
+		    while (isspace(*next))
+			next++;
+		    content_length = 0;
+		    for (;(*next >= '0' && *next <= '9'); next++) {
+			if ((content_length * 10) < content_length)
+			    break;
+			content_length = (content_length * 10) + (*next - '0');
+		    }
+		    /* In the case of overflow or other error ignore
+		     * Content-Length.
+		     */
+		    if (*next)
+			content_length = -1;
+		}
+		else if (strcasecmp(field_name, "Location") == 0) {
+		    next = field_value;
+		    /* Skip leading whitespace */
+		    while (isspace(*next))
+			next++;
+		    strlcpy(location, next, sizeof location);
+		}
+		/* Start the field name and field value afress */
+		field_name_len = 1;
+		field_name[0] = ch;
+		field_name[1] = '\0';
+		field_value_len = 0;
+		field_value[0] = '\0';
+		state = st_fieldname;
+	    }
+	    else /* Bogus try to recover */
+		state = st_skipline;
+	    break;
+
+	case st_fieldname:
+	    if (ch == ':' ) {
+		state = st_fieldvalue;
+	    }
+	    else if (is_token(ch)) {
+		if (!append_ch(field_name, sizeof field_name, &field_name_len, ch))
+		    state = st_skip_fieldname;
+	    }
+	    /* Bogus cases try to recover */
+	    else if (ch == '\n')
+		state = st_fieldfirst;
+	    else
+		state = st_skipline;
+	    break;
+
+	 case st_fieldvalue:
+	    if (ch == '\n')
+		state = st_fieldfirst;
+	    else {
+	    fieldvalue:
+		if (!append_ch(field_value, sizeof field_value, &field_value_len, ch))
+		    state = st_skip_fieldvalue;
+	    }
+	    break;
+
+	/* For valid fields whose names are longer than I choose to support. */
+	case st_skip_fieldname:
+	    if (ch == ':')
+		state = st_skip_fieldvalue;
+	    else if (is_token(ch))
+		state = st_skip_fieldname;
+	    /* Bogus cases try to recover */
+	    else if (ch == '\n')
+		state = st_fieldfirst;
+	    else
+		state = st_skipline;
+	    break;
+
+	/* For valid fields whose bodies are longer than I choose to support. */
+	case st_skip_fieldvalue:
+	    if (ch == '\n')
+		state = st_fieldfirst;
+	    break;
+
+	case st_eoh:
+	   break; /* Should never happen */
+	}
+    }
+
+    if (state != st_eoh)
+	status = 0;
+
+    switch (status) {
+    case 200:
+	/*
+	 * All OK, need to mark header data consumed and set up a file
+	 * structure...
+	 */
+	/* Treat the remainder of the bytes as data */
+	socket->tftp_filepos -= response_size;
+	break;
+    case 301:
+    case 302:
+    case 303:
+    case 307:
+	/* A redirect */
+	if (!location[0])
+	    goto fail;
+	*redir = location;
+	goto fail;
+    default:
+	goto fail;
+	break;
+    }
+    return;
+fail:
+    inode->size = 0;
+    tcp_close_file(inode);
+    return;
+}
diff --git a/core/fs/pxe/http_readdir.c b/core/fs/pxe/http_readdir.c
new file mode 100644
index 00000000..b6e480e7
--- /dev/null
+++ b/core/fs/pxe/http_readdir.c
@@ -0,0 +1,471 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2011 Intel Corporation; author: H. Peter Anvin
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ *   Boston MA 02110-1301, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+#include <inttypes.h>
+#include <string.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <dprintf.h>
+#include "pxe.h"
+
+enum http_readdir_state {
+    st_start,			/*  0 Initial state */
+    st_open,			/*  1 "<" */
+    st_a,			/*  2 "<a" */
+    st_attribute,		/*  3 "<a " */
+    st_h,			/*  4 "<a h" */
+    st_hr,			/*  5 */
+    st_hre,			/*  6 */
+    st_href,			/*  7 */
+    st_hrefeq,			/*  8 */
+    st_hrefqu,			/*  9 */
+    st_badtag,			/* 10 */
+    st_badtagqu,		/* 11 */
+    st_badattr,			/* 12 */
+    st_badattrqu,		/* 13 */
+};
+
+struct machine {
+    char xchar;
+    uint8_t st_xchar;
+    uint8_t st_left;		/* < */
+    uint8_t st_right;		/* > */
+    uint8_t st_space;		/* white */
+    uint8_t st_other;		/* anything else */
+};
+
+static const struct machine statemachine[] = {
+    /* xchar	st_xchar	st_left		st_right	st_space	st_other */
+    { 0,	0,		st_open,	st_start,	st_start,	st_start },
+    { 'a',	st_a,		st_badtag,	st_start,	st_open,	st_badtag },
+    { 0,	0,		st_open,	st_open,	st_attribute,	st_badtag },
+    { 'h',	st_h,		st_open,	st_start,	st_attribute,	st_badattr },
+    { 'r',	st_hr,		st_open,	st_start,	st_attribute,	st_badattr },
+    { 'e',	st_hre,		st_open,	st_start,	st_attribute,	st_badattr },
+    { 'f',	st_href,	st_open,	st_start,	st_attribute,	st_badattr },
+    { '=',	st_hrefeq,	st_open,	st_start,	st_attribute,	st_badattr },
+    { '\"',	st_hrefqu,	st_open,	st_start,	st_attribute,	st_hrefeq },
+    { '\"',	st_attribute,	st_hrefqu,	st_hrefqu,	st_hrefqu,	st_hrefqu },
+    { '\"',	st_badtagqu,	st_open,	st_start,	st_badtag,	st_badtag },
+    { '\"',	st_badtag,	st_badtagqu,	st_badtagqu,	st_badtagqu,	st_badtagqu },
+    { '\"',	st_badattrqu,	st_open,	st_start,	st_attribute,	st_badattr },
+    { '\"',	st_attribute,	st_badattrqu,	st_badattrqu,	st_badattrqu,	st_badattrqu },
+};
+
+struct html_entity {
+    uint16_t ucs;
+    const char entity[9];
+};
+
+static const struct html_entity entities[] = {
+    {   34, "quot" },
+    {   38, "amp" },
+    {   60, "lt" },
+    {   62, "gt" },
+#ifdef HTTP_ALL_ENTITIES
+    {  160, "nbsp" },
+    {  161, "iexcl" },
+    {  162, "cent" },
+    {  163, "pound" },
+    {  164, "curren" },
+    {  165, "yen" },
+    {  166, "brvbar" },
+    {  167, "sect" },
+    {  168, "uml" },
+    {  169, "copy" },
+    {  170, "ordf" },
+    {  171, "laquo" },
+    {  172, "not" },
+    {  173, "shy" },
+    {  174, "reg" },
+    {  175, "macr" },
+    {  176, "deg" },
+    {  177, "plusmn" },
+    {  178, "sup2" },
+    {  179, "sup3" },
+    {  180, "acute" },
+    {  181, "micro" },
+    {  182, "para" },
+    {  183, "middot" },
+    {  184, "cedil" },
+    {  185, "sup1" },
+    {  186, "ordm" },
+    {  187, "raquo" },
+    {  188, "frac14" },
+    {  189, "frac12" },
+    {  190, "frac34" },
+    {  191, "iquest" },
+    {  192, "Agrave" },
+    {  193, "Aacute" },
+    {  194, "Acirc" },
+    {  195, "Atilde" },
+    {  196, "Auml" },
+    {  197, "Aring" },
+    {  198, "AElig" },
+    {  199, "Ccedil" },
+    {  200, "Egrave" },
+    {  201, "Eacute" },
+    {  202, "Ecirc" },
+    {  203, "Euml" },
+    {  204, "Igrave" },
+    {  205, "Iacute" },
+    {  206, "Icirc" },
+    {  207, "Iuml" },
+    {  208, "ETH" },
+    {  209, "Ntilde" },
+    {  210, "Ograve" },
+    {  211, "Oacute" },
+    {  212, "Ocirc" },
+    {  213, "Otilde" },
+    {  214, "Ouml" },
+    {  215, "times" },
+    {  216, "Oslash" },
+    {  217, "Ugrave" },
+    {  218, "Uacute" },
+    {  219, "Ucirc" },
+    {  220, "Uuml" },
+    {  221, "Yacute" },
+    {  222, "THORN" },
+    {  223, "szlig" },
+    {  224, "agrave" },
+    {  225, "aacute" },
+    {  226, "acirc" },
+    {  227, "atilde" },
+    {  228, "auml" },
+    {  229, "aring" },
+    {  230, "aelig" },
+    {  231, "ccedil" },
+    {  232, "egrave" },
+    {  233, "eacute" },
+    {  234, "ecirc" },
+    {  235, "euml" },
+    {  236, "igrave" },
+    {  237, "iacute" },
+    {  238, "icirc" },
+    {  239, "iuml" },
+    {  240, "eth" },
+    {  241, "ntilde" },
+    {  242, "ograve" },
+    {  243, "oacute" },
+    {  244, "ocirc" },
+    {  245, "otilde" },
+    {  246, "ouml" },
+    {  247, "divide" },
+    {  248, "oslash" },
+    {  249, "ugrave" },
+    {  250, "uacute" },
+    {  251, "ucirc" },
+    {  252, "uuml" },
+    {  253, "yacute" },
+    {  254, "thorn" },
+    {  255, "yuml" },
+    {  338, "OElig" },
+    {  339, "oelig" },
+    {  352, "Scaron" },
+    {  353, "scaron" },
+    {  376, "Yuml" },
+    {  402, "fnof" },
+    {  710, "circ" },
+    {  732, "tilde" },
+    {  913, "Alpha" },
+    {  914, "Beta" },
+    {  915, "Gamma" },
+    {  916, "Delta" },
+    {  917, "Epsilon" },
+    {  918, "Zeta" },
+    {  919, "Eta" },
+    {  920, "Theta" },
+    {  921, "Iota" },
+    {  922, "Kappa" },
+    {  923, "Lambda" },
+    {  924, "Mu" },
+    {  925, "Nu" },
+    {  926, "Xi" },
+    {  927, "Omicron" },
+    {  928, "Pi" },
+    {  929, "Rho" },
+    {  931, "Sigma" },
+    {  932, "Tau" },
+    {  933, "Upsilon" },
+    {  934, "Phi" },
+    {  935, "Chi" },
+    {  936, "Psi" },
+    {  937, "Omega" },
+    {  945, "alpha" },
+    {  946, "beta" },
+    {  947, "gamma" },
+    {  948, "delta" },
+    {  949, "epsilon" },
+    {  950, "zeta" },
+    {  951, "eta" },
+    {  952, "theta" },
+    {  953, "iota" },
+    {  954, "kappa" },
+    {  955, "lambda" },
+    {  956, "mu" },
+    {  957, "nu" },
+    {  958, "xi" },
+    {  959, "omicron" },
+    {  960, "pi" },
+    {  961, "rho" },
+    {  962, "sigmaf" },
+    {  963, "sigma" },
+    {  964, "tau" },
+    {  965, "upsilon" },
+    {  966, "phi" },
+    {  967, "chi" },
+    {  968, "psi" },
+    {  969, "omega" },
+    {  977, "thetasym" },
+    {  978, "upsih" },
+    {  982, "piv" },
+    { 8194, "ensp" },
+    { 8195, "emsp" },
+    { 8201, "thinsp" },
+    { 8204, "zwnj" },
+    { 8205, "zwj" },
+    { 8206, "lrm" },
+    { 8207, "rlm" },
+    { 8211, "ndash" },
+    { 8212, "mdash" },
+    { 8216, "lsquo" },
+    { 8217, "rsquo" },
+    { 8218, "sbquo" },
+    { 8220, "ldquo" },
+    { 8221, "rdquo" },
+    { 8222, "bdquo" },
+    { 8224, "dagger" },
+    { 8225, "Dagger" },
+    { 8226, "bull" },
+    { 8230, "hellip" },
+    { 8240, "permil" },
+    { 8242, "prime" },
+    { 8243, "Prime" },
+    { 8249, "lsaquo" },
+    { 8250, "rsaquo" },
+    { 8254, "oline" },
+    { 8260, "frasl" },
+    { 8364, "euro" },
+    { 8465, "image" },
+    { 8472, "weierp" },
+    { 8476, "real" },
+    { 8482, "trade" },
+    { 8501, "alefsym" },
+    { 8592, "larr" },
+    { 8593, "uarr" },
+    { 8594, "rarr" },
+    { 8595, "darr" },
+    { 8596, "harr" },
+    { 8629, "crarr" },
+    { 8656, "lArr" },
+    { 8657, "uArr" },
+    { 8658, "rArr" },
+    { 8659, "dArr" },
+    { 8660, "hArr" },
+    { 8704, "forall" },
+    { 8706, "part" },
+    { 8707, "exist" },
+    { 8709, "empty" },
+    { 8711, "nabla" },
+    { 8712, "isin" },
+    { 8713, "notin" },
+    { 8715, "ni" },
+    { 8719, "prod" },
+    { 8721, "sum" },
+    { 8722, "minus" },
+    { 8727, "lowast" },
+    { 8730, "radic" },
+    { 8733, "prop" },
+    { 8734, "infin" },
+    { 8736, "ang" },
+    { 8743, "and" },
+    { 8744, "or" },
+    { 8745, "cap" },
+    { 8746, "cup" },
+    { 8747, "int" },
+    { 8756, "there4" },
+    { 8764, "sim" },
+    { 8773, "cong" },
+    { 8776, "asymp" },
+    { 8800, "ne" },
+    { 8801, "equiv" },
+    { 8804, "le" },
+    { 8805, "ge" },
+    { 8834, "sub" },
+    { 8835, "sup" },
+    { 8836, "nsub" },
+    { 8838, "sube" },
+    { 8839, "supe" },
+    { 8853, "oplus" },
+    { 8855, "otimes" },
+    { 8869, "perp" },
+    { 8901, "sdot" },
+    { 8968, "lceil" },
+    { 8969, "rceil" },
+    { 8970, "lfloor" },
+    { 8971, "rfloor" },
+    { 9001, "lang" },
+    { 9002, "rang" },
+    { 9674, "loz" },
+    { 9824, "spades" },
+    { 9827, "clubs" },
+    { 9829, "hearts" },
+    { 9830, "diams" },
+#endif /* HTTP_ALL_ENTITIES */
+    { 0, "" }
+};
+
+struct entity_state {
+    char entity_buf[16];
+    char *ep;
+};
+
+static char *emit(char *p, int c, struct entity_state *st)
+{
+    const struct html_entity *ent;
+    unsigned int ucs;
+
+    if (!st->ep) {
+	if (c == '&') {
+	    /* Entity open */
+	    st->ep = st->entity_buf;
+	} else {
+	    *p++ = c;
+	}
+    } else {
+	if (c == ';') {
+	    st->ep = NULL;
+	    *p = '\0';
+	    if (st->entity_buf[0] == '#') {
+		if ((st->entity_buf[1] | 0x20)== 'x') {
+		    ucs = strtoul(st->entity_buf + 2, NULL, 16);
+		} else {
+		    ucs = strtoul(st->entity_buf + 1, NULL, 10);
+		}
+	    } else {
+		for (ent = entities; ent->ucs; ent++) {
+		    if (!strcmp(st->entity_buf, ent->entity))
+			break;
+		}
+		ucs = ent->ucs;
+	    }
+	    if (ucs < 32 || ucs >= 0x10ffff)
+		return p;	/* Bogus */
+	    if (ucs >= 0x10000) {
+		*p++ = 0xf0 + (ucs >> 18);
+		*p++ = 0x80 + ((ucs >> 12) & 0x3f);
+		*p++ = 0x80 + ((ucs >> 6) & 0x3f);
+		*p++ = 0x80 + (ucs & 0x3f);
+	    } else if (ucs >= 0x800) {
+		*p++ = 0xe0 + (ucs >> 12);
+		*p++ = 0x80 + ((ucs >> 6) & 0x3f);
+		*p++ = 0x80 + (ucs & 0x3f);
+	    } else if (ucs >= 0x80) {
+		*p++ = 0xc0 + (ucs >> 6);
+		*p++ = 0x80 + (ucs & 0x3f);
+	    } else {
+		*p++ = ucs;
+	    }
+	} else if (st->ep < st->entity_buf + sizeof st->entity_buf - 1) {
+	    *st->ep++ = c;
+	}
+    }
+    return p;
+}
+
+static const char *http_get_filename(struct inode *inode, char *buf)
+{
+    int c, lc;
+    char *p;
+    const struct machine *sm;
+    struct entity_state es;
+    enum http_readdir_state state = st_start;
+    enum http_readdir_state pstate = st_start;
+
+    memset(&es, 0, sizeof es);
+
+    p = buf;
+    for (;;) {
+	c = pxe_getc(inode);
+	if (c == -1)
+	    return NULL;
+
+	lc = tolower(c);
+
+	sm = &statemachine[state];
+
+	if (lc == sm->xchar)
+	    state = sm->st_xchar;
+	else if (c == '<')
+	    state = sm->st_left;
+	else if (c == '>')
+	    state = sm->st_right;
+	else if (isspace(c))
+	    state = sm->st_space;
+	else
+	    state = sm->st_other;
+
+	if (state == st_hrefeq || state == st_hrefqu) {
+	    if (state != pstate)
+		p = buf;
+	    else if (p < buf + FILENAME_MAX)
+		p = emit(p, c, &es);
+	    pstate = state;
+	} else {
+	    if (pstate != st_start)
+		pstate = st_start;
+	    if (p != buf && state == st_start) {
+		*p = '\0';
+		return buf;
+	    }
+	}
+    }
+}
+
+int http_readdir(struct inode *inode, struct dirent *dirent)
+{
+    char buf[FILENAME_MAX + 6];
+    const char *fn, *sp;
+
+    for (;;) {
+	fn = http_get_filename(inode, buf);
+
+	if (!fn)
+	    return -1;		/* End of directory */
+
+	/* Ignore entries with http special characters */
+	if (strchr(fn, '#'))
+	    continue;
+	if (strchr(fn, '?'))
+	    continue;
+
+	/* A slash if present has to be the last character, and not the first */
+	sp = strchr(fn, '/');
+	if (sp) {
+	    if (sp == fn || sp[1])
+		continue;
+	} else {
+	    sp = strchr(fn, '\0');
+	}
+
+	if (sp > fn + NAME_MAX)
+	    continue;
+
+	dirent->d_ino = 0;	/* Not applicable */
+	dirent->d_off = 0;	/* Not applicable */
+	dirent->d_reclen = offsetof(struct dirent, d_name) + (sp-fn) + 1;
+	dirent->d_type = *sp == '/' ? DT_DIR : DT_REG;
+	memcpy(dirent->d_name, fn, sp-fn);
+	dirent->d_name[sp-fn] = '\0';
+	return 0;
+    }
+}
diff --git a/core/fs/pxe/idle.c b/core/fs/pxe/idle.c
index 52a87c34..1d1bb8bc 100644
--- a/core/fs/pxe/idle.c
+++ b/core/fs/pxe/idle.c
@@ -19,91 +19,8 @@
 #include <sys/cpu.h>
 #include "pxe.h"
 
-static int pxe_idle_poll(void)
-{
-    static __lowmem char junk_pkt[PKTBUF_SIZE];
-    static __lowmem t_PXENV_UDP_READ read_buf;
-
-    memset(&read_buf, 0, sizeof read_buf);
-
-    read_buf.src_ip  = 0;	 /* Any destination */
-    read_buf.dest_ip = IPInfo.myip;
-    read_buf.s_port  = 0;	 /* Any source port */
-    read_buf.d_port  = htons(9); /* Discard port (not used...) */
-    read_buf.buffer_size = sizeof junk_pkt;
-    read_buf.buffer  = FAR_PTR(junk_pkt);
-
-    pxe_call(PXENV_UDP_READ, &read_buf);
-
-    return 0;
-}
-
-static uint32_t pxe_detect_nic_type(void)
-{
-    static __lowmem t_PXENV_UNDI_GET_NIC_TYPE nic_type;
-
-    if (pxe_call(PXENV_UNDI_GET_NIC_TYPE, &nic_type))
-	return -1;		/* Unknown NIC */
-
-    if (nic_type.NicType != PCI_NIC && nic_type.NicType != CardBus_NIC)
-	return -1;		/* Not a PCI NIC */
-
-    /*
-     * Return VID:DID as a single number, with the VID in the high word
-     * -- this is opposite from the usual order, but it makes it easier to
-     * enforce that the table is sorted.
-     */
-    return (nic_type.info.pci.Vendor_ID << 16) + nic_type.info.pci.Dev_ID;
-}
-
-#define PCI_DEV(vid, did)	(((vid) << 16) + (did))
-
-/* This array should be sorted!! */
-static const uint32_t pxe_need_idle_drain[] =
-{
-    /*
-     * Older Broadcom NICs: they need receive calls on idle to avoid
-     * FIFO stalls.
-     */
-    PCI_DEV(0x14e4, 0x1659),	/* BCM5721 */
-    PCI_DEV(0x14e4, 0x165a),	/* BCM5722 */
-    PCI_DEV(0x14e4, 0x165b),	/* BCM5723 */
-    PCI_DEV(0x14e4, 0x1668),	/* BCM5714 */
-    PCI_DEV(0x14e4, 0x1669),	/* BCM5714S */
-    PCI_DEV(0x14e4, 0x166a),	/* BCM5780 */
-    PCI_DEV(0x14e4, 0x1673),	/* BCM5755M */
-    PCI_DEV(0x14e4, 0x1674),	/* BCM5756ME */
-    PCI_DEV(0x14e4, 0x1678),	/* BCM5715 */
-    PCI_DEV(0x14e4, 0x1679),	/* BCM5715S */
-    PCI_DEV(0x14e4, 0x167b),	/* BCM5755 */
-};
-
 void pxe_idle_init(void)
 {
-    uint32_t dev_id = pxe_detect_nic_type();
-    int l, h;
-    bool found;
-
-    l = 0;
-    h = sizeof pxe_need_idle_drain / sizeof pxe_need_idle_drain[0] - 1;
-
-    found = false;
-    while (h >= l) {
-	int x = (l+h) >> 1;
-	uint32_t id = pxe_need_idle_drain[x];
-
-	if (id == dev_id) {
-	    found = true;
-	    break;
-	} else if (id < dev_id) {
-	    l = x+1;
-	} else {
-	    h = x-1;
-	}
-    }
-
-    if (found)
-	idle_hook_func = pxe_idle_poll;
 }
 
 void pxe_idle_cleanup(void)
diff --git a/core/fs/pxe/isr.c b/core/fs/pxe/isr.c
new file mode 100644
index 00000000..069fefd5
--- /dev/null
+++ b/core/fs/pxe/isr.c
@@ -0,0 +1,278 @@
+/*
+ * core/fs/pxe/isr.c
+ *
+ * Stub invoked on return from real mode including from an interrupt.
+ * Interrupts are locked out on entry.
+ */
+
+#include "core.h"
+#include "thread.h"
+#include "pxe.h"
+#include <string.h>
+#include <sys/cpu.h>
+#include <sys/io.h>
+
+extern uint8_t pxe_irq_pending;
+extern volatile uint8_t pxe_need_poll;
+static DECLARE_INIT_SEMAPHORE(pxe_receive_thread_sem, 0);
+static DECLARE_INIT_SEMAPHORE(pxe_poll_thread_sem, 0);
+static struct thread *pxe_thread, *poll_thread;
+
+/*
+ * Note: this *must* be called with interrupts enabled.
+ */
+static bool install_irq_vector(uint8_t irq, void (*isr)(void), far_ptr_t *old)
+{
+    far_ptr_t *entry;
+    unsigned int vec;
+    uint8_t mask, mymask;
+    uint32_t now;
+    bool ok;
+
+    if (irq < 8)
+	vec = irq + 0x08;
+    else if (irq < 16)
+	vec = (irq - 8) + 0x70;
+    else
+	return false;
+
+    cli();
+
+    if (pxe_need_poll) {
+	sti();
+	return false;
+    }
+
+    entry = (far_ptr_t *)(vec << 2);
+    *old = *entry;
+    entry->ptr = (uint32_t)isr;
+
+    /* Enable this interrupt at the PIC level, just in case... */
+    mymask = ~(1 << (irq & 7));
+    if (irq >= 8) {
+	mask = inb(0x21);
+	mask &= ~(1 << 2);	/* Enable cascade */
+	outb(mask, 0x21);
+ 	mask = inb(0xa1);
+	mask &= mymask;
+	outb(mask, 0xa1);
+    } else {
+ 	mask = inb(0x21);
+	mask &= mymask;
+	outb(mask, 0x21);
+    }
+
+    sti();
+
+    now = jiffies();
+
+    /* Some time to watch for stuck interrupts */
+    while (jiffies() - now < 4 && (ok = !pxe_need_poll))
+	hlt();
+
+    if (!ok)
+	*entry = *old;		/* Restore the old vector */
+
+    printf("UNDI: IRQ %d(0x%02x): %04x:%04x -> %04x:%04x\n", irq, vec,
+	   old->seg, old->offs, entry->seg, entry->offs);
+
+    return ok;
+}
+
+static bool uninstall_irq_vector(uint8_t irq, void (*isr), far_ptr_t *old)
+{
+    far_ptr_t *entry;
+    unsigned int vec;
+    bool rv;
+
+    if (!irq)
+	return true;		/* Nothing to uninstall */
+
+    if (irq < 8)
+	vec = irq + 0x08;
+    else if (irq < 16)
+	vec = (irq - 8) + 0x70;
+    else
+	return false;
+
+    cli();
+
+    entry = (far_ptr_t *)(vec << 2);
+
+    if (entry->ptr != (uint32_t)isr) {
+	rv = false;
+    } else {
+	*entry = *old;
+	rv = true;
+    }
+
+    sti();
+    return rv;
+}
+
+static void pxe_poll_wakeups(void)
+{
+    static jiffies_t last_jiffies = 0;
+    jiffies_t now = jiffies();
+
+    if (pxe_need_poll == 1) {
+	/* If we need polling now, activate polling */
+	pxe_need_poll = 3;
+	sem_up(&pxe_poll_thread_sem);
+    }
+
+    if (now != last_jiffies) {
+	last_jiffies = now;
+	__thread_process_timeouts();
+    }
+
+    if (pxe_irq_pending) {
+	pxe_irq_pending = 0;
+	sem_up(&pxe_receive_thread_sem);
+    }
+}
+
+static void pxe_process_irq(void)
+{
+    static __lowmem t_PXENV_UNDI_ISR isr;
+
+    uint16_t func = PXENV_UNDI_ISR_IN_PROCESS; /* First time */
+    bool done = false;
+
+    while (!done) {
+        memset(&isr, 0, sizeof isr);
+        isr.FuncFlag = func;
+        func = PXENV_UNDI_ISR_IN_GET_NEXT; /* Next time */
+
+        pxe_call(PXENV_UNDI_ISR, &isr);
+
+        switch (isr.FuncFlag) {
+        case PXENV_UNDI_ISR_OUT_DONE:
+	    done = true;
+	    break;
+
+        case PXENV_UNDI_ISR_OUT_TRANSMIT:
+	    /* Transmit complete - nothing for us to do */
+	    break;
+
+        case PXENV_UNDI_ISR_OUT_RECEIVE:
+	    undiif_input(&isr);
+	    break;
+
+        case PXENV_UNDI_ISR_OUT_BUSY:
+	/* ISR busy, this should not happen */
+	    done = true;
+	    break;
+
+        default:
+	/* Invalid return code, this should not happen */
+	    done = true;
+	    break;
+        }
+    }
+}
+
+static void pxe_receive_thread(void *dummy)
+{
+    (void)dummy;
+
+    for (;;) {
+	sem_down(&pxe_receive_thread_sem, 0);
+	pxe_process_irq();
+    }
+}
+
+static bool pxe_isr_poll(void)
+{
+    static __lowmem t_PXENV_UNDI_ISR isr;
+
+    isr.FuncFlag = PXENV_UNDI_ISR_IN_START;
+    pxe_call(PXENV_UNDI_ISR, &isr);
+
+    return isr.FuncFlag == PXENV_UNDI_ISR_OUT_OURS;
+}
+
+static void pxe_poll_thread(void *dummy)
+{
+    (void)dummy;
+
+    /* Block indefinitely unless activated */
+    sem_down(&pxe_poll_thread_sem, 0);
+
+    for (;;) {
+	cli();
+	if (pxe_receive_thread_sem.count < 0 && pxe_isr_poll())
+	    sem_up(&pxe_receive_thread_sem);
+	else
+	    __schedule();
+	sti();
+	cpu_relax();
+    }
+}
+
+/*
+ * This does preparations and enables the PXE thread
+ */
+void pxe_init_isr(void)
+{
+    start_idle_thread();
+    sched_hook_func = pxe_poll_wakeups;
+    /*
+     * Run the pxe receive thread at elevated priority, since the UNDI
+     * stack is likely to have very limited memory available; therefore to
+     * avoid packet loss we need to move it into memory that we ourselves
+     * manage, as soon as possible.
+     */
+    core_pm_hook = __schedule;
+
+    pxe_thread = start_thread("pxe receive", 16384, -20,
+			      pxe_receive_thread, NULL);
+}
+
+/*
+ * Actually start the interrupt routine inside the UNDI stack
+ */
+void pxe_start_isr(void)
+{
+    int irq = pxe_undi_info.IntNumber;
+
+    if (irq == 2)
+	irq = 9;		/* IRQ 2 is really IRQ 9 */
+    else if (irq > 15)
+	irq = 0;		/* Invalid IRQ */
+
+    pxe_irq_vector = irq;
+
+    if (irq) {
+	if (!install_irq_vector(irq, pxe_isr, &pxe_irq_chain))
+	    irq = 0;		/* Install failed or stuck interrupt */
+    }
+    
+    poll_thread = start_thread("pxe poll", 4096, POLL_THREAD_PRIORITY,
+			       pxe_poll_thread, NULL);
+
+    if (!irq ||	!(pxe_undi_iface.ServiceFlags & PXE_UNDI_IFACE_FLAG_IRQ))
+	asm volatile("orb $1,%0" : "+m" (pxe_need_poll));
+}
+
+int reset_pxe(void)
+{
+    static __lowmem struct s_PXENV_UNDI_CLOSE undi_close;
+
+    sched_hook_func = NULL;
+    core_pm_hook = core_pm_null_hook;
+    kill_thread(pxe_thread);
+
+    memset(&undi_close, 0, sizeof(undi_close));
+    pxe_call(PXENV_UNDI_CLOSE, &undi_close);
+
+    if (undi_close.Status)
+	printf("PXENV_UNDI_CLOSE failed: 0x%x\n", undi_close.Status);
+
+    if (pxe_irq_vector)
+	uninstall_irq_vector(pxe_irq_vector, pxe_isr, &pxe_irq_chain);
+    if (poll_thread)
+	kill_thread(poll_thread);
+
+    return undi_close.Status;
+}
diff --git a/core/fs/pxe/pxe.c b/core/fs/pxe/pxe.c
index c07f00ee..9f18f282 100644
--- a/core/fs/pxe/pxe.c
+++ b/core/fs/pxe/pxe.c
@@ -5,10 +5,16 @@
 #include <bios.h>
 #include <fs.h>
 #include <minmax.h>
+#include <fcntl.h>
 #include <sys/cpu.h>
 #include "pxe.h"
+#include "thread.h"
+#include "url.h"
+#include "tftp.h"
+#include <net.h>
 
-#define GPXE 1
+__lowmem t_PXENV_UNDI_GET_INFORMATION pxe_undi_info;
+__lowmem t_PXENV_UNDI_GET_IFACE_INFO  pxe_undi_iface;
 
 static uint16_t real_base_mem;	   /* Amount of DOS memory after freeing */
 
@@ -16,45 +22,26 @@ uint8_t MAC[MAC_MAX];		   /* Actual MAC address */
 uint8_t MAC_len;                   /* MAC address len */
 uint8_t MAC_type;                  /* MAC address type */
 
-char __bss16 BOOTIFStr[7+3*(MAC_MAX+1)];
-#define MAC_str (BOOTIFStr+7)	/* The actual hardware address */
-char __bss16 SYSUUIDStr[8+32+5];
-#define UUID_str (SYSUUIDStr+8)	/* The actual UUID */
-
 char boot_file[256];		   /* From DHCP */
 char path_prefix[256];		   /* From DHCP */
-char dot_quad_buf[16];
 
 static bool has_gpxe;
 static uint32_t gpxe_funcs;
 bool have_uuid = false;
 
-/* Common receive buffer */
-static __lowmem char packet_buf[PKTBUF_SIZE] __aligned(16);
-
-const uint8_t TimeoutTable[] = {
-    2, 2, 3, 3, 4, 5, 6, 7, 9, 10, 12, 15, 18, 21, 26, 31, 37, 44,
-    53, 64, 77, 92, 110, 132, 159, 191, 229, 255, 255, 255, 255, 0
-};
-
-struct tftp_options {
-    const char *str_ptr;        /* string pointer */
-    size_t      offset;		/* offset into socket structre */
-};
-
-#define IFIELD(x)	offsetof(struct inode, x)
-#define PFIELD(x)	(offsetof(struct inode, pvt) + \
-			 offsetof(struct pxe_pvt_inode, x))
-
-static const struct tftp_options tftp_options[] =
-{
-    { "tsize",   IFIELD(size) },
-    { "blksize", PFIELD(tftp_blksize) },
+static struct url_scheme {
+    const char *name;
+    void (*open)(struct url_info *, int, struct inode *, const char **);
+    int ok_flags;
+} url_schemes[] = {
+    { "tftp", tftp_open, 0 },
+#ifdef IS_LPXELINUX
+    { "http", http_open, O_DIRECTORY },
+    { "ftp",  ftp_open,  O_DIRECTORY },
+#endif
+    { NULL, NULL, 0 },
 };
-static const int tftp_nopts = sizeof tftp_options / sizeof tftp_options[0];
-
-static void tftp_error(struct inode *file, uint16_t errnum,
-		       const char *errstr);
+#define OK_FLAGS_MASK	(O_DIRECTORY|O_WRONLY)
 
 /*
  * Allocate a local UDP port structure and assign it a local port number.
@@ -67,108 +54,35 @@ static struct inode *allocate_socket(struct fs_info *fs)
     if (!inode) {
 	malloc_error("socket structure");
     } else {
-	struct pxe_pvt_inode *socket = PVT(inode);
-	socket->tftp_localport = get_port();
 	inode->mode = DT_REG;	/* No other types relevant for PXE */
     }
 
     return inode;
 }
 
-static void free_socket(struct inode *inode)
+void free_socket(struct inode *inode)
 {
     struct pxe_pvt_inode *socket = PVT(inode);
 
-    free_port(socket->tftp_localport);
+    free(socket->tftp_pktbuf);	/* If we allocated a buffer, free it now */
     free_inode(inode);
 }
 
-#if GPXE
-static void gpxe_close_file(struct inode *inode)
-{
-    struct pxe_pvt_inode *socket = PVT(inode);
-    static __lowmem struct s_PXENV_FILE_CLOSE file_close;
-
-    file_close.FileHandle = socket->tftp_remoteport;
-    pxe_call(PXENV_FILE_CLOSE, &file_close);
-}
-#endif
-
 static void pxe_close_file(struct file *file)
 {
     struct inode *inode = file->inode;
     struct pxe_pvt_inode *socket = PVT(inode);
 
+    if (!inode)
+	return;
+
     if (!socket->tftp_goteof) {
-#if GPXE
-	if (socket->tftp_localport == 0xffff) {
-	    gpxe_close_file(inode);
-	} else
-#endif
-	if (socket->tftp_localport != 0) {
-	    tftp_error(inode, 0, "No error, file close");
-	}
+	socket->ops->close(inode);
     }
 
     free_socket(inode);
 }
 
-/**
- * Take a nubmer of bytes in memory and convert to lower-case hxeadecimal
- *
- * @param: dst, output buffer
- * @param: src, input buffer
- * @param: count, number of bytes
- *
- */
-static void lchexbytes(char *dst, const void *src, int count)
-{
-    uint8_t half;
-    uint8_t c;
-    const uint8_t *s = src;
-
-    for(; count > 0; count--) {
-        c = *s++;
-        half   = ((c >> 4) & 0x0f) + '0';
-        *dst++ = half > '9' ? (half + 'a' - '9' - 1) : half;
-
-        half   = (c & 0x0f) + '0';
-        *dst++ = half > '9' ? (half + 'a' - '9' - 1) : half;
-    }
-}
-
-/*
- * just like the lchexbytes, except to upper-case
- *
- */
-static void uchexbytes(char *dst, const void *src, int count)
-{
-    uint8_t half;
-    uint8_t c;
-    const uint8_t *s = src;
-
-    for(; count > 0; count--) {
-        c = *s++;
-        half   = ((c >> 4) & 0x0f) + '0';
-        *dst++ = half > '9' ? (half + 'A' - '9' - 1) : half;
-
-        half   = (c & 0x0f) + '0';
-        *dst++ = half > '9' ? (half + 'A' - '9' - 1) : half;
-    }
-}
-
-/*
- * Parse a single hexadecimal byte, which must be complete (two
- * digits).  This is used in URL parsing.
- */
-static int hexbyte(const char *p)
-{
-    if (!is_hex(p[0]) || !is_hex(p[1]))
-	return -1;
-    else
-	return (hexval(p[0]) << 4) + hexval(p[1]);
-}
-
 /*
  * Tests an IP address in _ip_ for validity; return with 0 for bad, 1 for good.
  * We used to refuse class E, but class E addresses are likely to become
@@ -197,57 +111,11 @@ bool ip_ok(uint32_t ip)
  */
 static int gendotquad(char *dst, uint32_t ip)
 {
-    int part;
-    int i = 0, j;
-    char temp[4];
-    char *p = dst;
-
-    for (; i < 4; i++) {
-        j = 0;
-        part = ip & 0xff;
-        do {
-            temp[j++] = (part % 10) + '0';
-        }while(part /= 10);
-        for (; j > 0; j--)
-            *p++ = temp[j-1];
-        *p++ = '.';
-
-        ip >>= 8;
-    }
-    /* drop the last dot '.' and zero-terminate string*/
-    *(--p) = 0;
-
-    return p - dst;
-}
-
-/*
- * parse the ip_str and return the ip address with *res.
- * return the the string address after the ip string
- *
- */
-static const char *parse_dotquad(const char *ip_str, uint32_t *res)
-{
-    const char *p = ip_str;
-    uint8_t part = 0;
-    uint32_t ip = 0;
-    int i;
-
-    for (i = 0; i < 4; i++) {
-        while (is_digit(*p)) {
-            part = part * 10 + *p - '0';
-            p++;
-        }
-        if (i != 3 && *p != '.')
-            return NULL;
-
-        ip = (ip << 8) | part;
-        part = 0;
-        p++;
-    }
-    p--;
-
-    *res = htonl(ip);
-    return p;
+    return sprintf(dst, "%u.%u.%u.%u",
+		   ((const uint8_t *)&ip)[0],
+		   ((const uint8_t *)&ip)[1],
+		   ((const uint8_t *)&ip)[2],
+		   ((const uint8_t *)&ip)[3]);
 }
 
 /*
@@ -256,11 +124,14 @@ static const char *parse_dotquad(const char *ip_str, uint32_t *res)
  */
 __export int pxe_call(int opcode, void *data)
 {
+    static DECLARE_INIT_SEMAPHORE(pxe_sem, 1);
     extern void pxenv(void);
     com32sys_t regs;
 
+    sem_down(&pxe_sem, 0);
+
 #if 0
-    printf("pxe_call op %04x data %p\n", opcode, data);
+    dprintf("pxe_call op %04x data %p\n", opcode, data);
 #endif
 
     memset(&regs, 0, sizeof regs);
@@ -269,77 +140,11 @@ __export int pxe_call(int opcode, void *data)
     regs.edi.w[0] = OFFS(data);
     call16(pxenv, &regs, &regs);
 
-    return regs.eflags.l & EFLAGS_CF;  /* CF SET if fail */
-}
-
-/**
- * Send an ERROR packet.  This is used to terminate a connection.
- *
- * @inode:	Inode structure
- * @errnum:	Error number (network byte order)
- * @errstr:	Error string (included in packet)
- */
-static void tftp_error(struct inode *inode, uint16_t errnum,
-		       const char *errstr)
-{
-    static __lowmem struct {
-	uint16_t err_op;
-	uint16_t err_num;
-	char err_msg[64];
-    } __packed err_buf;
-    static __lowmem struct s_PXENV_UDP_WRITE udp_write;
-    int len = min(strlen(errstr), sizeof(err_buf.err_msg)-1);
-    struct pxe_pvt_inode *socket = PVT(inode);
-
-    err_buf.err_op  = TFTP_ERROR;
-    err_buf.err_num = errnum;
-    memcpy(err_buf.err_msg, errstr, len);
-    err_buf.err_msg[len] = '\0';
-
-    udp_write.src_port    = socket->tftp_localport;
-    udp_write.dst_port    = socket->tftp_remoteport;
-    udp_write.ip          = socket->tftp_remoteip;
-    udp_write.gw          = gateway(udp_write.ip);
-    udp_write.buffer      = FAR_PTR(&err_buf);
-    udp_write.buffer_size = 4 + len + 1;
+    sem_up(&pxe_sem);
 
-    /* If something goes wrong, there is nothing we can do, anyway... */
-    pxe_call(PXENV_UDP_WRITE, &udp_write);
-}
-
-
-/**
- * Send ACK packet. This is a common operation and so is worth canning.
- *
- * @param: inode,   Inode pointer
- * @param: ack_num, Packet # to ack (network byte order)
- *
- */
-static void ack_packet(struct inode *inode, uint16_t ack_num)
-{
-    int err;
-    static __lowmem uint16_t ack_packet_buf[2];
-    static __lowmem struct s_PXENV_UDP_WRITE udp_write;
-    struct pxe_pvt_inode *socket = PVT(inode);
-
-    /* Packet number to ack */
-    ack_packet_buf[0]     = TFTP_ACK;
-    ack_packet_buf[1]     = ack_num;
-    udp_write.src_port    = socket->tftp_localport;
-    udp_write.dst_port    = socket->tftp_remoteport;
-    udp_write.ip          = socket->tftp_remoteip;
-    udp_write.gw          = gateway(udp_write.ip);
-    udp_write.buffer      = FAR_PTR(ack_packet_buf);
-    udp_write.buffer_size = 4;
-
-    err = pxe_call(PXENV_UDP_WRITE, &udp_write);
-    (void)err;
-#if 0
-    printf("sent %s\n", err ? "FAILED" : "OK");
-#endif
+    return regs.eflags.l & EFLAGS_CF;  /* CF SET if fail */
 }
 
-
 /**
  * Get a DHCP packet from the PXE stack into a lowmem buffer
  *
@@ -353,7 +158,7 @@ static int pxe_get_cached_info(int type, void *buf, size_t bufsiz)
     static __lowmem struct s_PXENV_GET_CACHED_INFO get_cached_info;
     printf(" %02x", type);
 
-    get_cached_info.Status      = 0;
+    memset(&get_cached_info, 0, sizeof get_cached_info);
     get_cached_info.PacketType  = type;
     get_cached_info.BufferSize  = bufsiz;
     get_cached_info.Buffer      = FAR_PTR(buf);
@@ -366,104 +171,13 @@ static int pxe_get_cached_info(int type, void *buf, size_t bufsiz)
     return get_cached_info.BufferSize;
 }
 
-
-/*
- * Return the type of pathname passed.
- */
-enum pxe_path_type {
-    PXE_RELATIVE,		/* No :: or URL */
-    PXE_HOMESERVER,		/* Starting with :: */
-    PXE_TFTP,			/* host:: */
-    PXE_URL_TFTP,		/* tftp:// */
-    PXE_URL,			/* Absolute URL syntax */
-};
-
-static enum pxe_path_type pxe_path_type(const char *str)
-{
-    const char *p;
-    
-    p = str;
-
-    while (1) {
-	switch (*p) {
-	case ':':
-	    if (p[1] == ':') {
-		if (p == str)
-		    return PXE_HOMESERVER;
-		else
-		    return PXE_TFTP;
-	    } else if (p > str && p[1] == '/' && p[2] == '/') {
-		if (!strncasecmp(str, "tftp://", 7))
-		    return PXE_URL_TFTP;
-		else
-		    return PXE_URL;
-	    }
-
-	    /* else fall through */
-	case '/': case '!': case '@': case '#': case '%':
-	case '^': case '&': case '*': case '(': case ')':
-	case '[': case ']': case '{': case '}': case '\\':
-	case '|': case '=': case '`': case '~': case '\'':
-	case '\"': case ';': case '>': case '<': case '?':
-	case '\0':
-	    /* Any of these characters terminate the colon search */
-	    return PXE_RELATIVE;
-	default:
-	    break;
-	}
-	p++;
-    }
-}
-
-#if GPXE
-
-/**
- * Get a fresh packet from a gPXE socket
- * @param: inode -> Inode pointer
- *
- */
-static void get_packet_gpxe(struct inode *inode)
-{
-    struct pxe_pvt_inode *socket = PVT(inode);
-    static __lowmem struct s_PXENV_FILE_READ file_read;
-    int err;
-
-    while (1) {
-        file_read.FileHandle  = socket->tftp_remoteport;
-        file_read.Buffer      = FAR_PTR(packet_buf);
-        file_read.BufferSize  = PKTBUF_SIZE;
-        err = pxe_call(PXENV_FILE_READ, &file_read);
-        if (!err)  /* successed */
-            break;
-
-        if (file_read.Status != PXENV_STATUS_TFTP_OPEN)
-	    kaboom();
-    }
-
-    memcpy(socket->tftp_pktbuf, packet_buf, file_read.BufferSize);
-
-    socket->tftp_dataptr   = socket->tftp_pktbuf;
-    socket->tftp_bytesleft = file_read.BufferSize;
-    socket->tftp_filepos  += file_read.BufferSize;
-
-    if (socket->tftp_bytesleft == 0)
-        inode->size = socket->tftp_filepos;
-
-    /* if we're done here, close the file */
-    if (inode->size > socket->tftp_filepos)
-        return;
-
-    /* Got EOF, close it */
-    socket->tftp_goteof = 1;
-    gpxe_close_file(inode);
-}
-#endif /* GPXE */
-
-
 /*
  * mangle a filename pointed to by _src_ into a buffer pointed
  * to by _dst_; ends on encountering any whitespace.
  *
+ * This deliberately does not attempt to do any conversion of
+ * pathname separators.
+ *
  */
 static void pxe_mangle_name(char *dst, const char *src)
 {
@@ -476,109 +190,40 @@ static void pxe_mangle_name(char *dst, const char *src)
 }
 
 /*
- * Get a fresh packet if the buffer is drained, and we haven't hit
- * EOF yet.  The buffer should be filled immediately after draining!
+ * Read a single character from the specified pxe inode.
+ * Very useful for stepping through http streams and
+ * parsing their headers.
  */
-static void fill_buffer(struct inode *inode)
+int pxe_getc(struct inode *inode)
 {
-    int err;
-    int last_pkt;
-    const uint8_t *timeout_ptr;
-    uint8_t timeout;
-    uint16_t buffersize;
-    uint32_t oldtime;
-    void *data = NULL;
-    static __lowmem struct s_PXENV_UDP_READ udp_read;
     struct pxe_pvt_inode *socket = PVT(inode);
+    unsigned char byte;
 
-    if (socket->tftp_bytesleft || socket->tftp_goteof)
-        return;
+    while (!socket->tftp_bytesleft) {
+	if (socket->tftp_goteof)
+	    return -1;
 
-#if GPXE
-    if (socket->tftp_localport == 0xffff) {
-        get_packet_gpxe(inode);
-        return;
+	socket->ops->fill_buffer(inode);
     }
-#endif
 
-    /*
-     * Start by ACKing the previous packet; this should cause
-     * the next packet to be sent.
-     */
-    timeout_ptr = TimeoutTable;
-    timeout = *timeout_ptr++;
-    oldtime = jiffies();
-
- ack_again:
-    ack_packet(inode, socket->tftp_lastpkt);
-
-    while (timeout) {
-        udp_read.buffer      = FAR_PTR(packet_buf);
-        udp_read.buffer_size = PKTBUF_SIZE;
-        udp_read.src_ip      = socket->tftp_remoteip;
-        udp_read.dest_ip     = IPInfo.myip;
-        udp_read.s_port      = socket->tftp_remoteport;
-        udp_read.d_port      = socket->tftp_localport;
-        err = pxe_call(PXENV_UDP_READ, &udp_read);
-        if (err) {
-	    uint32_t now = jiffies();
-
-	    if (now-oldtime >= timeout) {
-		oldtime = now;
-		timeout = *timeout_ptr++;
-		if (!timeout)
-		    break;
-	    }
-            continue;
-        }
+    byte = *socket->tftp_dataptr;
+    socket->tftp_bytesleft -= 1;
+    socket->tftp_dataptr += 1;
 
-        if (udp_read.buffer_size < 4)  /* Bad size for a DATA packet */
-            continue;
-
-        data = packet_buf;
-        if (*(uint16_t *)data != TFTP_DATA)    /* Not a data packet */
-            continue;
-
-        /* If goes here, recevie OK, break */
-        break;
-    }
-
-    /* time runs out */
-    if (timeout == 0)
-	kaboom();
+    return byte;
+}
 
-    last_pkt = socket->tftp_lastpkt;
-    last_pkt = ntohs(last_pkt);       /* Host byte order */
-    last_pkt++;
-    last_pkt = htons(last_pkt);       /* Network byte order */
-    if (*(uint16_t *)(data + 2) != last_pkt) {
-        /*
-         * Wrong packet, ACK the packet and try again.
-         * This is presumably because the ACK got lost,
-         * so the server just resent the previous packet.
-         */
-#if 0
-	printf("Wrong packet, wanted %04x, got %04x\n", \
-               htons(last_pkt), htons(*(uint16_t *)(data+2)));
-#endif
-        goto ack_again;
-    }
+/*
+ * Get a fresh packet if the buffer is drained, and we haven't hit
+ * EOF yet.  The buffer should be filled immediately after draining!
+ */
+static void fill_buffer(struct inode *inode)
+{
+    struct pxe_pvt_inode *socket = PVT(inode);
+    if (socket->tftp_bytesleft || socket->tftp_goteof)
+        return;
 
-    /* It's the packet we want.  We're also EOF if the size < blocksize */
-    socket->tftp_lastpkt = last_pkt;    /* Update last packet number */
-    buffersize = udp_read.buffer_size - 4;  /* Skip TFTP header */
-    memcpy(socket->tftp_pktbuf, packet_buf + 4, buffersize);
-    socket->tftp_dataptr = socket->tftp_pktbuf;
-    socket->tftp_filepos += buffersize;
-    socket->tftp_bytesleft = buffersize;
-    if (buffersize < socket->tftp_blksize) {
-        /* it's the last block, ACK packet immediately */
-        ack_packet(inode, *(uint16_t *)(data + 2));
-
-        /* Make sure we know we are at end of file */
-        inode->size 		= socket->tftp_filepos;
-        socket->tftp_goteof	= 1;
-    }
+    return socket->ops->fill_buffer(inode);
 }
 
 
@@ -635,8 +280,20 @@ static uint32_t pxe_getfssec(struct file *file, char *buf,
     return bytes_read;
 }
 
+/*
+ * Assign an IP address to a URL
+ */
+static void url_set_ip(struct url_info *url)
+{
+    url->ip = 0;
+    if (url->host)
+	url->ip = dns_resolv(url->host);
+    if (!url->ip)
+	url->ip = IPInfo.serverip;
+}
+
 /**
- * Open a TFTP connection to the server
+ * Open the specified connection
  *
  * @param:filename, the file we wanna open
  *
@@ -644,352 +301,95 @@ static uint32_t pxe_getfssec(struct file *file, char *buf,
  * @out: the lenght of this file, stores in file->file_len
  *
  */
-static void __pxe_searchdir(const char *filename, struct file *file);
+static void __pxe_searchdir(const char *filename, int flags, struct file *file);
 extern uint16_t PXERetry;
 
-static void pxe_searchdir(const char *filename, struct file *file)
+static void pxe_searchdir(const char *filename, int flags, struct file *file)
 {
     int i = PXERetry;
 
     do {
 	dprintf("PXE: file = %p, retries left = %d: ", file, i);
-	__pxe_searchdir(filename, file);
+	__pxe_searchdir(filename, flags, file);
 	dprintf("%s\n", file->inode ? "ok" : "failed");
     } while (!file->inode && i--);
 }
-
-static void __pxe_searchdir(const char *filename, struct file *file)
+static void __pxe_searchdir(const char *filename, int flags, struct file *file)
 {
     struct fs_info *fs = file->fs;
     struct inode *inode;
-    struct pxe_pvt_inode *socket;
-    char *buf;
-    const char *np;
-    char *p;
-    char *options;
-    char *data;
-    static __lowmem struct s_PXENV_UDP_WRITE udp_write;
-    static __lowmem struct s_PXENV_UDP_READ  udp_read;
-    static __lowmem struct s_PXENV_FILE_OPEN file_open;
-    static const char rrq_tail[] = "octet\0""tsize\0""0\0""blksize\0""1408";
-    static __lowmem char rrq_packet_buf[2+2*FILENAME_MAX+sizeof rrq_tail];
-    const struct tftp_options *tftp_opt;
-    int i = 0;
-    int err;
-    int buffersize;
-    int rrq_len;
-    const uint8_t  *timeout_ptr;
-    uint32_t timeout;
-    uint32_t oldtime;
-    uint16_t tid;
-    uint16_t opcode;
-    uint16_t blk_num;
-    uint32_t ip = 0;
-    uint32_t opdata, *opdata_ptr;
-    enum pxe_path_type path_type;
     char fullpath[2*FILENAME_MAX];
-    uint16_t server_port = TFTP_PORT;  /* TFTP server port */
+#if GPXE
+    char urlsave[2*FILENAME_MAX];
+#endif
+    struct url_info url;
+    const struct url_scheme *us = NULL;
+    int redirect_count = 0;
+    bool found_scheme = false;
 
     inode = file->inode = NULL;
-	
-    buf = rrq_packet_buf;
-    *(uint16_t *)buf = TFTP_RRQ;  /* TFTP opcode */
-    buf += 2;
-
-    path_type = pxe_path_type(filename);
-    if (path_type == PXE_RELATIVE) {
-	snprintf(fullpath, sizeof fullpath, "%s%s", fs->cwd_name, filename);
-	path_type = pxe_path_type(filename = fullpath);
-    }
 
-    switch (path_type) {
-    case PXE_RELATIVE:		/* Really shouldn't happen... */
-    case PXE_URL:
-	buf = stpcpy(buf, filename);
-	ip = IPInfo.serverip;	/* Default server */
-	break;
-
-    case PXE_HOMESERVER:
-	buf = stpcpy(buf, filename+2);
-	ip = IPInfo.serverip;
-	break;
-
-    case PXE_TFTP:
-	np = strchr(filename, ':');
-	buf = stpcpy(buf, np+2);
-	if (parse_dotquad(filename, &ip) != np)
-	    ip = dns_resolv(filename);
-	break;
-
-    case PXE_URL_TFTP:
-	np = filename + 7;
-	while (*np && *np != '/' && *np != ':')
-	    np++;
-	if (np > filename + 7) {
-	    if (parse_dotquad(filename + 7, &ip) != np)
-		ip = dns_resolv(filename + 7);
-	}
-	if (*np == ':') {
-	    np++;
-	    server_port = 0;
-	    while (*np >= '0' && *np <= '9')
-		server_port = server_port * 10 + *np++ - '0';
-	    server_port = server_port ? htons(server_port) : TFTP_PORT;
-	}
-	if (*np == '/')
-	    np++;		/* Do *NOT* eat more than one slash here... */
-	/*
-	 * The ; is because of a quirk in the TFTP URI spec (RFC
-	 * 3617); it is to be followed by TFTP modes, which we just ignore.
-	 */
-	while (*np && *np != ';') {
-	    int v;
-	    if (*np == '%' && (v = hexbyte(np+1)) > 0) {
-		*buf++ = v;
-		np += 3;
-	    } else {
-		*buf++ = *np++;
-	    }
-	}
-	*buf = '\0';
-	break;
-    }
-
-    buf++;			/* Point *past* the final NULL */
-    memcpy(buf, rrq_tail, sizeof rrq_tail);
-    buf += sizeof rrq_tail;
-
-    rrq_len = buf - rrq_packet_buf;
-
-    inode = allocate_socket(fs);
-    if (!inode)
-	return;			/* Allocation failure */
-    socket = PVT(inode);
+    while (filename) {
+	if (redirect_count++ > 5)
+	    break;
 
+	strlcpy(fullpath, filename, sizeof fullpath);
 #if GPXE
-    if (path_type == PXE_URL) {
-	if (has_gpxe) {
-	    file_open.Status        = PXENV_STATUS_BAD_FUNC;
-	    file_open.FileName      = FAR_PTR(rrq_packet_buf + 2);
-	    err = pxe_call(PXENV_FILE_OPEN, &file_open);
-	    if (err)
-		goto done;
-	    
-	    socket->tftp_localport = -1;
-	    socket->tftp_remoteport = file_open.FileHandle;
-	    inode->size = -1;
-	    goto done;
-	} else {
-	    static bool already = false;
-	    if (!already) {
-		printf("URL syntax, but gPXE extensions not detected, "
-		       "trying plain TFTP...\n");
-		already = true;
-	    }
+	strcpy(urlsave, fullpath);
+#endif
+	parse_url(&url, fullpath);
+	if (url.type == URL_SUFFIX) {
+	    snprintf(fullpath, sizeof fullpath, "%s%s", fs->cwd_name, filename);
+#if GPXE
+	    strcpy(urlsave, fullpath);
+#endif
+	    parse_url(&url, fullpath);
 	}
-    }
-#endif /* GPXE */
-
-    if (!ip)
-	    goto done;		/* No server */
-
-    timeout_ptr = TimeoutTable;   /* Reset timeout */
-    
-sendreq:
-    timeout = *timeout_ptr++;
-    if (!timeout) {
-	free_socket(inode);
-	return;			/* No file available... */
-    }
-    oldtime = jiffies();
-
-    socket->tftp_remoteip = ip;
-    tid = socket->tftp_localport;   /* TID(local port No) */
-    udp_write.buffer    = FAR_PTR(rrq_packet_buf);
-    udp_write.ip        = ip;
-    udp_write.gw        = gateway(udp_write.ip);
-    udp_write.src_port  = tid;
-    udp_write.dst_port  = server_port;
-    udp_write.buffer_size = rrq_len;
-    pxe_call(PXENV_UDP_WRITE, &udp_write);
-
-    /* If the WRITE call fails, we let the timeout take care of it... */
-
-wait_pkt:
-    for (;;) {
-        buf                  = packet_buf;
-	udp_read.status      = 0;
-        udp_read.buffer      = FAR_PTR(buf);
-        udp_read.buffer_size = PKTBUF_SIZE;
-        udp_read.dest_ip     = IPInfo.myip;
-        udp_read.d_port      = tid;
-        err = pxe_call(PXENV_UDP_READ, &udp_read);
-        if (err || udp_read.status) {
-	    uint32_t now = jiffies();
-	    if (now - oldtime >= timeout)
-		goto sendreq;
-        } else {
-	    /* Make sure the packet actually came from the server */
-	    if (udp_read.src_ip == socket->tftp_remoteip)
+
+	inode = allocate_socket(fs);
+	if (!inode)
+	    return;			/* Allocation failure */
+	
+	url_set_ip(&url);
+	
+	filename = NULL;
+	found_scheme = false;
+	for (us = url_schemes; us->name; us++) {
+	    if (!strcmp(us->name, url.scheme)) {
+		if ((flags & ~us->ok_flags & OK_FLAGS_MASK) == 0)
+		    us->open(&url, flags, inode, &filename);
+		found_scheme = true;
 		break;
+	    }
 	}
-    }
-
-    socket->tftp_remoteport = udp_read.s_port;
-
-    /* filesize <- -1 == unknown */
-    inode->size = -1;
-    /* Default blksize unless blksize option negotiated */
-    socket->tftp_blksize = TFTP_BLOCKSIZE;
-    buffersize = udp_read.buffer_size - 2;  /* bytes after opcode */
-    if (buffersize < 0)
-        goto wait_pkt;                     /* Garbled reply */
-
-    /*
-     * Get the opcode type, and parse it
-     */
-    opcode = *(uint16_t *)packet_buf;
-    switch (opcode) {
-    case TFTP_ERROR:
-        inode->size = 0;
-        break;			/* ERROR reply; don't try again */
-
-    case TFTP_DATA:
-        /*
-         * If the server doesn't support any options, we'll get a
-         * DATA reply instead of OACK. Stash the data in the file
-         * buffer and go with the default value for all options...
-         *
-         * We got a DATA packet, meaning no options are
-         * suported. Save the data away and consider the
-         * length undefined, *unless* this is the only
-         * data packet...
-         */
-        buffersize -= 2;
-        if (buffersize < 0)
-            goto wait_pkt;
-        data = packet_buf + 2;
-        blk_num = *(uint16_t *)data;
-        data += 2;
-        if (blk_num != htons(1))
-            goto wait_pkt;
-        socket->tftp_lastpkt = blk_num;
-        if (buffersize > TFTP_BLOCKSIZE)
-            goto err_reply;  /* Corrupt */
-        else if (buffersize < TFTP_BLOCKSIZE) {
-            /*
-             * This is the final EOF packet, already...
-             * We know the filesize, but we also want to
-             * ack the packet and set the EOF flag.
-             */
-            inode->size = buffersize;
-            socket->tftp_goteof = 1;
-            ack_packet(inode, blk_num);
-        }
-
-        socket->tftp_bytesleft = buffersize;
-        socket->tftp_dataptr = socket->tftp_pktbuf;
-        memcpy(socket->tftp_pktbuf, data, buffersize);
-	break;
-
-    case TFTP_OACK:
-        /*
-         * Now we need to parse the OACK packet to get the transfer
-         * and packet sizes.
-         */
-
-        options = packet_buf + 2;
-	p = options;
-
-	while (buffersize) {
-	    const char *opt = p;
 
-	    /*
-	     * If we find an option which starts with a NUL byte,
-	     * (a null option), we're either seeing garbage that some
-	     * TFTP servers add to the end of the packet, or we have
-	     * no clue how to parse the rest of the packet (what is
-	     * an option name and what is a value?)  In either case,
-	     * discard the rest.
-	     */
-	    if (!*opt)
-		goto done;
-
-            while (buffersize) {
-                if (!*p)
-                    break;	/* Found a final null */
-                *p++ |= 0x20;
-		buffersize--;
-            }
-	    if (!buffersize)
-		break;		/* Unterminated option */
-
-	    /* Consume the terminal null */
-	    p++;
-	    buffersize--;
-
-	    if (!buffersize)
-		break;		/* No option data */
-
-            /*
-             * Parse option pointed to by options; guaranteed to be
-	     * null-terminated
-             */
-            tftp_opt = tftp_options;
-            for (i = 0; i < tftp_nopts; i++) {
-                if (!strcmp(opt, tftp_opt->str_ptr))
-                    break;
-                tftp_opt++;
-            }
-            if (i == tftp_nopts)
-                goto err_reply; /* Non-negotitated option returned,
-				   no idea what it means ...*/
-
-            /* get the address of the filed that we want to write on */
-            opdata_ptr = (uint32_t *)((char *)inode + tftp_opt->offset);
-	    opdata = 0;
-
-            /* do convert a number-string to decimal number, just like atoi */
-            while (buffersize--) {
-		uint8_t d = *p++;
-                if (d == '\0')
-                    break;              /* found a final null */
-		d -= '0';
-                if (d > 9)
-                    goto err_reply;     /* Not a decimal digit */
-                opdata = opdata*10 + d;
-            }
-	    *opdata_ptr = opdata;
-	}
-	break;
+	/* filename here is set on a redirect */
+    }
 
-    default:
-	printf("TFTP unknown opcode %d\n", ntohs(opcode));
-	goto err_reply;
+    if (!found_scheme) {
+#if GPXE
+	/* No URL scheme found, hand it to GPXE */
+	gpxe_open(inode, urlsave);
+#endif
     }
 
-done:
-    if (!inode->size) {
+    if (inode->size) {
+	file->inode = inode;
+	file->inode->mode = (flags & O_DIRECTORY) ? DT_DIR : DT_REG;
+    } else {
         free_socket(inode);
-	return;
     }
-    file->inode = inode;
-    return;
 
-err_reply:
-    /* Build the TFTP error packet */
-    tftp_error(inode, TFTP_EOPTNEG, "TFTP protocol error");
-    printf("TFTP server sent an incomprehesible reply\n");
-    kaboom();
+    return;
 }
 
 
 static int __pxe_chdir(struct fs_info *fs, const char *src,
-		       enum pxe_path_type path_type)
+		       enum url_type url_type)
 {
-    if (path_type == PXE_RELATIVE)
+    if (url_type == URL_SUFFIX)
 	strlcat(fs->cwd_name, src, sizeof fs->cwd_name);
-    else if (path_type == PXE_HOMESERVER)
+    else if (url_type == URL_OLD_TFTP)
 	snprintf(fs->cwd_name, sizeof fs->cwd_name, "::%s", src);
     else
 	strlcpy(fs->cwd_name, src, sizeof fs->cwd_name);
@@ -1031,7 +431,7 @@ static void get_prefix(void)
     }
 
     printf("TFTP prefix: %s\n", path_prefix);
-    __pxe_chdir(this_fs, path_prefix, PXE_HOMESERVER);
+    __pxe_chdir(this_fs, path_prefix, URL_OLD_TFTP);
 }
 
 /*
@@ -1040,10 +440,8 @@ static void get_prefix(void)
 static size_t pxe_realpath(struct fs_info *fs, char *dst, const char *src,
 			   size_t bufsize)
 {
-    enum pxe_path_type path_type = pxe_path_type(src);
-
     return snprintf(dst, bufsize, "%s%s",
-		    path_type == PXE_RELATIVE ? fs->cwd_name : "", src);
+		    url_type(src) == URL_SUFFIX ? fs->cwd_name : "", src);
 }
 
 /*
@@ -1052,9 +450,7 @@ static size_t pxe_realpath(struct fs_info *fs, char *dst, const char *src,
 static int pxe_chdir(struct fs_info *fs, const char *src)
 {
     /* The cwd for PXE is just a text prefix */
-    enum pxe_path_type path_type = pxe_path_type(src);
-
-    __pxe_chdir(fs, src, path_type);
+    __pxe_chdir(fs, src, url_type(src));
 
     dprintf("cwd = \"%s\"\n", fs->cwd_name);
     return 0;
@@ -1078,7 +474,7 @@ static int pxe_open_config(struct com32_filedata *filedata)
     get_prefix();
     if (DHCPMagic & 0x02) {
         /* We got a DHCP option, try it first */
-	if (open_file(ConfigName, filedata) >= 0)
+	if (open_file(ConfigName, O_RDONLY, filedata) >= 0)
 	    return 0;
     }
 
@@ -1088,23 +484,23 @@ static int pxe_open_config(struct com32_filedata *filedata)
     config_file = stpcpy(ConfigName, cfgprefix);
 
     /* Try loading by UUID */
-    if (have_uuid) {
-	strcpy(config_file, UUID_str);
-	if (open_file(ConfigName, filedata) >= 0)
+    if (sysappend_strings[SYSAPPEND_SYSUUID]) {
+	strcpy(config_file, sysappend_strings[SYSAPPEND_SYSUUID]+8);
+	if (open_file(ConfigName, O_RDONLY, filedata) >= 0)
             return 0;
     }
 
     /* Try loading by MAC address */
-    strcpy(config_file, MAC_str);
-    if (open_file(ConfigName, filedata) >= 0)
+    strcpy(config_file, sysappend_strings[SYSAPPEND_BOOTIF]+7);
+    if (open_file(ConfigName, O_RDONLY, filedata) >= 0)
         return 0;
 
     /* Nope, try hexadecimal IP prefixes... */
-    uchexbytes(config_file, (uint8_t *)&IPInfo.myip, 4);
+    sprintf(config_file, "%08X", ntohl(IPInfo.myip));
     last = &config_file[8];
     while (tries) {
         *last = '\0';        /* Zero-terminate string */
-	if (open_file(ConfigName, filedata) >= 0)
+	if (open_file(ConfigName, O_RDONLY, filedata) >= 0)
             return 0;
         last--;           /* Drop one character */
         tries--;
@@ -1112,7 +508,7 @@ static int pxe_open_config(struct com32_filedata *filedata)
 
     /* Final attempt: "default" string */
     strcpy(config_file, default_str);
-    if (open_file(ConfigName, filedata) >= 0)
+    if (open_file(ConfigName, O_RDONLY, filedata) >= 0)
         return 0;
 
     printf("%-68s\n", "Unable to locate configuration file");
@@ -1124,43 +520,17 @@ static int pxe_open_config(struct com32_filedata *filedata)
  */
 static void make_bootif_string(void)
 {
+    static char bootif_str[7+3*(MAC_MAX+1)];
     const uint8_t *src;
-    char *dst = BOOTIFStr;
+    char *dst = bootif_str;
     int i;
 
     dst += sprintf(dst, "BOOTIF=%02x", MAC_type);
     src = MAC;
     for (i = MAC_len; i; i--)
 	dst += sprintf(dst, "-%02x", *src++);
-}
-/*
- * Generate the SYSUUID string, if we have one...
- */
-static void make_sysuuid_string(void)
-{
-    static const uint8_t uuid_dashes[] = {4, 2, 2, 2, 6, 0};
-    const uint8_t *src = uuid;
-    const uint8_t *uuid_ptr = uuid_dashes;
-    char *dst;
 
-    SYSUUIDStr[0] = '\0';	/* If nothing there... */
-
-    /* Try loading by UUID */
-    if (have_uuid) {
-	dst = stpcpy(SYSUUIDStr, "SYSUUID=");
-
-        while (*uuid_ptr) {
-	    int len = *uuid_ptr;
-
-            lchexbytes(dst, src, len);
-            dst += len * 2;
-            src += len;
-            uuid_ptr++;
-            *dst++ = '-';
-        }
-        /* Remove last dash and zero-terminate */
-	*--dst = '\0';
-    }
+    sysappend_strings[SYSAPPEND_BOOTIF] = bootif_str;
 }
 
 /*
@@ -1168,21 +538,22 @@ static void make_sysuuid_string(void)
  * option into IPOption based on DHCP information in IPInfo.
  *
  */
-char __bss16 IPOption[3+4*16];
-
 static void genipopt(void)
 {
-    char *p = IPOption;
+    static char ip_option[3+4*16];
     const uint32_t *v = &IPInfo.myip;
+    char *p;
     int i;
 
-    p = stpcpy(p, "ip=");
+    p = stpcpy(ip_option, "ip=");
 
     for (i = 0; i < 4; i++) {
 	p += gendotquad(p, *v++);
 	*p++ = ':';
     }
     *--p = '\0';
+
+    sysappend_strings[SYSAPPEND_IP] = ip_option;
 }
 
 
@@ -1190,6 +561,7 @@ static void genipopt(void)
 static void ip_init(void)
 {
     uint32_t ip = IPInfo.myip;
+    char dot_quad_buf[16];
 
     genipopt();
     gendotquad(dot_quad_buf, ip);
@@ -1199,20 +571,6 @@ static void ip_init(void)
 }
 
 /*
- * Print the IPAPPEND strings, in order
- */
-static void print_ipappend(void)
-{
-    size_t i;
-
-    for (i = 0; i < (size_t)numIPAppends; i++) {
-	const char *p = (const char *)(size_t)IPAppends[i];
-	if (*p)
-	    printf("%s\n", p);
-    }
-}
-
-/*
  * Validity check on possible !PXE structure in buf
  * return 1 for success, 0 for failure.
  *
@@ -1413,6 +771,8 @@ static int pxe_init(bool quiet)
 
     real_base_mem = max(code_seg, data_seg) >> 6; /* Convert to kilobytes */
 
+    probe_undi();
+
     return 0;
 }
 
@@ -1437,24 +797,6 @@ static void gpxe_init(void)
 }
 
 /*
- * Initialize UDP stack
- *
- */
-static void udp_init(void)
-{
-    int err;
-    static __lowmem struct s_PXENV_UDP_OPEN udp_open;
-    udp_open.src_ip = IPInfo.myip;
-    err = pxe_call(PXENV_UDP_OPEN, &udp_open);
-    if (err || udp_open.status) {
-        printf("Failed to initialize UDP stack ");
-        printf("%d\n", udp_open.status);
-	kaboom();
-    }
-}
-
-
-/*
  * Network-specific initialization
  */
 static void network_init(void)
@@ -1514,10 +856,12 @@ static void network_init(void)
     lfree(bp);
 
     make_bootif_string();
-    make_sysuuid_string();
+    /* If DMI and DHCP disagree, which one should we set? */
+    if (have_uuid)
+	sysappend_set_uuid(uuid);
     ip_init();
-    print_ipappend();
 
+    /* print_sysappend(); */
     /*
      * Check to see if we got any PXELINUX-specific DHCP options; in particular,
      * if we didn't get the magic enable, do not recognize any other options.
@@ -1525,7 +869,7 @@ static void network_init(void)
     if ((DHCPMagic & 1) == 0)
         DHCPMagic = 0;
 
-    udp_init();
+    net_core_init();
 }
 
 /*
@@ -1536,9 +880,8 @@ static int pxe_fs_init(struct fs_info *fs)
 {
     (void)fs;    /* drop the compile warning message */
 
-    /* This block size is actually arbitrary... */
-    fs->sector_shift = fs->block_shift = TFTP_BLOCKSIZE_LG2;
-    fs->sector_size  = fs->block_size  = 1 << TFTP_BLOCKSIZE_LG2;
+    /* Prepare for handling pxe interrupts */
+    pxe_init_isr();
 
     /* This block size is actually arbitrary... */
     fs->sector_shift = fs->block_shift = TFTP_BLOCKSIZE_LG2;
@@ -1600,9 +943,9 @@ static inline bool is_efi(const struct efi_struct *efi)
     return (efi->magic == EFI_MAGIC) && (efi->len >= 83);
 }
 
+#if 0
 static void install_int18_hack(void)
 {
-#if 0
     static const uint8_t int18_hack[] =
     {
 	0xcd, 0x18,			/* int $0x18 */
@@ -1638,30 +981,8 @@ static void install_int18_hack(void)
 	    *(uint16_t *)(dst+46) = InitStack.seg;
 	}
     }
-#endif
-}
-
-int reset_pxe(void)
-{
-    static __lowmem struct s_PXENV_UDP_CLOSE udp_close;
-    extern void gpxe_unload(void);
-    int err = 0;
-
-    pxe_idle_cleanup();
-
-    pxe_call(PXENV_UDP_CLOSE, &udp_close);
-
-    if (gpxe_funcs & 0x80) {
-	/* gPXE special unload implemented */
-	call16(gpxe_unload, &zero_regs, NULL);
-
-	/* Locate the actual vendor stack... */
-	err = pxe_init(true);
-    }
-
-    install_int18_hack();
-    return err;
 }
+#endif
 
 /*
  * This function unloads the PXE and UNDI stacks and
@@ -1670,6 +991,12 @@ int reset_pxe(void)
 __export void unload_pxe(uint16_t flags)
 {
     /* PXE unload sequences */
+    /*
+     * iPXE does:
+     * UNDI_SHUTDOWN, UNDI_CLEANUP, STOP_UNDI
+     * Older Syslinux did:
+     * UDP_CLOSE, UNDI_SHUTDOWN, UNLOAD_STACK, STOP_UNDI/UNDI_CLEANUP
+     */
     static const uint8_t new_api_unload[] = {
 	PXENV_UNDI_SHUTDOWN, PXENV_UNLOAD_STACK, PXENV_STOP_UNDI, 0
     };
@@ -1689,6 +1016,7 @@ __export void unload_pxe(uint16_t flags)
 	uint16_t Status;	/* All calls have this as the first member */
     } unload_call;
 
+    dprintf("Called unload_pxe()...\n");
     dprintf("FBM before unload = %d\n", bios_fbm());
 
     err = reset_pxe();
@@ -1707,7 +1035,8 @@ __export void unload_pxe(uint16_t flags)
 	memset(&unload_call, 0, sizeof unload_call);
 	err = pxe_call(api, &unload_call);
 	if (err || unload_call.Status != PXENV_STATUS_SUCCESS) {
-	    dprintf("PXE unload API call %04x failed\n", api);
+	    printf("PXE unload API call %04x failed: 0x%x\n",
+		   api, unload_call.Status);
 	    goto cant_free;
 	}
     }
@@ -1739,6 +1068,17 @@ cant_free:
     return;
 }
 
+static int pxe_readdir(struct file *file, struct dirent *dirent)
+{
+    struct inode *inode = file->inode;
+    struct pxe_pvt_inode *socket = PVT(inode);
+
+    if (socket->ops->readdir)
+	return socket->ops->readdir(inode, dirent);
+    else
+	return -1;		/* No such operation */
+}
+
 const struct fs_ops pxe_fs_ops = {
     .fs_name       = "pxe",
     .fs_flags      = FS_NODEV,
@@ -1751,4 +1091,5 @@ const struct fs_ops pxe_fs_ops = {
     .mangle_name   = pxe_mangle_name,
     .chdir_start   = pxe_chdir_start,
     .open_config   = pxe_open_config,
+    .readdir	   = pxe_readdir,
 };
diff --git a/core/fs/pxe/pxe.h b/core/fs/pxe/pxe.h
index d4377581..2d4be3b1 100644
--- a/core/fs/pxe/pxe.h
+++ b/core/fs/pxe/pxe.h
@@ -1,7 +1,7 @@
 /* -----------------------------------------------------------------------
  *
  *   Copyright 1999-2008 H. Peter Anvin - All Rights Reserved
- *   Copyright 2009-2010 Intel Corporation; author: H. Peter Anvin
+ *   Copyright 2009-2011 Intel Corporation; author: H. Peter Anvin
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -21,67 +21,21 @@
 #define PXE_H
 
 #include <syslinux/pxe_api.h>
-#include "fs.h"			/* For MAX_OPEN, should go away */
+#include "fs.h"			/* Mostly for FILENAME_MAX */
 
 /*
  * Some basic defines...
  */
-#define TFTP_PORT        htons(69)              /* Default TFTP port */
-#define TFTP_BLOCKSIZE_LG2 9
-#define TFTP_BLOCKSIZE  (1 << TFTP_BLOCKSIZE_LG2)
-#define PKTBUF_SIZE     2048			/*  */
+#define PKTBUF_SIZE     2048	/* Used mostly by the gPXE backend */
 
 #define is_digit(c)     (((c) >= '0') && ((c) <= '9'))
 
-static inline bool is_hex(char c)
-{
-    return (c >= '0' && c <= '9') ||
-	(c >= 'A' && c <= 'F') ||
-	(c >= 'a' && c <= 'f');
-}
-
-static inline int hexval(char c)
-{
-    return (c >= 'A') ? (c & ~0x20) - 'A' + 10 : (c - '0');
-}
-
-/*
- * TFTP operation codes
- */
-#define TFTP_RRQ	 htons(1)		// Read rest
-#define TFTP_WRQ	 htons(2)		// Write rest
-#define TFTP_DATA	 htons(3)		// Data packet
-#define TFTP_ACK	 htons(4)		// ACK packet
-#define TFTP_ERROR	 htons(5)		// ERROR packet
-#define TFTP_OACK	 htons(6)		// OACK packet
-
-/*
- * TFTP error codes
- */
-#define TFTP_EUNDEF	 htons(0)		// Unspecified error
-#define TFTP_ENOTFOUND	 htons(1)		// File not found
-#define TFTP_EACCESS	 htons(2)		// Access violation
-#define TFTP_ENOSPACE	 htons(3)		// Disk full
-#define TFTP_EBADOP	 htons(4)		// Invalid TFTP operation
-#define TFTP_EBADID	 htons(5)		// Unknown transfer
-#define TFTP_EEXISTS	 htons(6)		// File exists
-#define TFTP_ENOUSER	 htons(7)		// No such user
-#define TFTP_EOPTNEG	 htons(8)		// Option negotiation failure
-
-
 #define BOOTP_OPTION_MAGIC  htonl(0x63825363)
 #define MAC_MAX 32
 
-/* Defines for DNS */
-#define DNS_PORT	htons(53)		/* Default DNS port */
-#define DNS_MAX_PACKET	512			/* Defined by protocol */
-#define DNS_MAX_SERVERS 4			/* Max no of DNS servers */
-
-
 /*
- * structures 
+ * structures
  */
-
 struct pxenv_t {
     uint8_t    signature[6];	/* PXENV+ */
     uint16_t   version;
@@ -149,22 +103,42 @@ struct bootp_t {
     uint8_t  options[1260]; /* Vendor options */
 } __attribute__ ((packed));
 
+struct netconn;
+struct netbuf;
 /*
  * Our inode private information -- this includes the packet buffer!
  */
+struct pxe_conn_ops {
+    void (*fill_buffer)(struct inode *inode);
+    void (*close)(struct inode *inode);
+    int (*readdir)(struct inode *inode, struct dirent *dirent);
+};    
+
+struct net_private {
+#ifdef IS_LPXELINUX
+    struct netconn *conn;      /* lwip network connection */
+    struct netbuf *buf;	       /* lwip cached buffer */
+#else
+    uint16_t tftp_localport;   /* Local port number  (0=not in use) */
+    uint32_t tftp_remoteip;    /* Remote IP address (0 = disconnected) */
+#endif
+
+};
+
 struct pxe_pvt_inode {
-    uint16_t tftp_localport;   /* Local port number  (0=not in us)*/
-    uint16_t tftp_remoteport;  /* Remote port number */
-    uint32_t tftp_remoteip;    /* Remote IP address */
-    uint32_t tftp_filepos;     /* bytes downloaded (includeing buffer) */
-    uint32_t tftp_blksize;     /* Block size for this connection(*) */
-    uint16_t tftp_bytesleft;   /* Unclaimed data bytes */
-    uint16_t tftp_lastpkt;     /* Sequence number of last packet (NBO) */
-    char    *tftp_dataptr;     /* Pointer to available data */
-    uint8_t  tftp_goteof;      /* 1 if the EOF packet received */
-    uint8_t  tftp_unused[3];   /* Currently unused */
-    char     tftp_pktbuf[PKTBUF_SIZE];
-} __attribute__ ((packed));
+    struct net_private private;   /* Network stack private data */
+    uint16_t tftp_remoteport;     /* Remote port number */
+    uint32_t tftp_filepos;        /* bytes downloaded (including buffer) */
+    uint32_t tftp_blksize;        /* Block size for this connection(*) */
+    uint16_t tftp_bytesleft;      /* Unclaimed data bytes */
+    uint16_t tftp_lastpkt;        /* Sequence number of last packet (HBO) */
+    char    *tftp_dataptr;        /* Pointer to available data */
+    uint8_t  tftp_goteof;         /* 1 if the EOF packet received */
+    uint8_t  tftp_unused[3];      /* Currently unused */
+    char    *tftp_pktbuf;         /* Packet buffer */
+    struct inode *ctl;	          /* Control connection (for FTP) */
+    const struct pxe_conn_ops *ops;
+};
 
 #define PVT(i) ((struct pxe_pvt_inode *)((i)->pvt))
 
@@ -184,6 +158,9 @@ struct ip_info {
  */
 extern struct ip_info IPInfo;
 
+extern t_PXENV_UNDI_GET_INFORMATION pxe_undi_info;
+extern t_PXENV_UNDI_GET_IFACE_INFO  pxe_undi_iface;
+
 extern uint8_t MAC[];
 extern char BOOTIFStr[];
 extern uint8_t MAC_len;
@@ -196,9 +173,6 @@ extern char boot_file[];
 extern char path_prefix[];
 extern char LocalDomain[];
 
-extern char IPOption[];
-extern char dot_quad_buf[];
-
 extern uint32_t dns_server[];
 
 extern uint16_t APIVer;
@@ -211,8 +185,6 @@ extern bool have_uuid;
 extern uint8_t uuid_type;
 extern uint8_t uuid[];
 
-extern const uint8_t TimeoutTable[];
-
 /*
  * Compute the suitable gateway for a specific route -- too many
  * vendor PXE stacks don't do this correctly...
@@ -226,24 +198,62 @@ static inline uint32_t gateway(uint32_t ip)
 }
 
 /*
- * functions 
+ * functions
  */
 
+/* pxeisr.inc */
+extern uint8_t pxe_irq_vector;
+extern void pxe_isr(void);
+extern far_ptr_t pxe_irq_chain;
+extern void pxe_poll(void);
+
+/* isr.c */
+void pxe_init_isr(void);
+void pxe_start_isr(void);
+int reset_pxe(void);
+
 /* pxe.c */
+struct url_info;
 bool ip_ok(uint32_t);
+int pxe_getc(struct inode *inode);
+void free_socket(struct inode *inode);
+
+/* undiif.c */
+int undiif_start(uint32_t ip, uint32_t netmask, uint32_t gw);
+void undiif_input(t_PXENV_UNDI_ISR *isr);
 
 /* dhcp_options.c */
 void parse_dhcp(const void *, size_t);
 
-/* dnsresolv.c */
-int dns_mangle(char **, const char *);
-
 /* idle.c */
 void pxe_idle_init(void);
 void pxe_idle_cleanup(void);
 
-/* socknum.c */
-uint16_t get_port(void);
-void free_port(uint16_t port);
+/* tftp.c */
+void tftp_open(struct url_info *url, int flags, struct inode *inode,
+	       const char **redir);
+
+/* gpxeurl.c */
+void gpxe_open(struct inode *inode, const char *url);
+#define GPXE 0
+
+/* http.c */
+void http_open(struct url_info *url, int flags, struct inode *inode,
+	       const char **redir);
+
+/* http_readdir.c */
+int http_readdir(struct inode *inode, struct dirent *dirent);
+
+/* ftp.c */
+void ftp_open(struct url_info *url, int flags, struct inode *inode,
+	      const char **redir);
+
+/* ftp_readdir.c */
+int ftp_readdir(struct inode *inode, struct dirent *dirent);
+
+/* tcp.c */
+void tcp_close_file(struct inode *inode);
+void tcp_fill_buffer(struct inode *inode);
+const struct pxe_conn_ops tcp_conn_ops;
 
 #endif /* pxe.h */
diff --git a/core/fs/pxe/tcp.c b/core/fs/pxe/tcp.c
new file mode 100644
index 00000000..528fbce8
--- /dev/null
+++ b/core/fs/pxe/tcp.c
@@ -0,0 +1,78 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2011 Intel Corporation; author: H. Peter Anvin
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ *   Boston MA 02110-1301, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * tcp.c
+ *
+ * Common operations for TCP-based network protocols
+ */
+
+#include <lwip/api.h>
+#include "pxe.h"
+#include "../../../version.h"
+#include "url.h"
+
+void tcp_close_file(struct inode *inode)
+{
+    struct pxe_pvt_inode *socket = PVT(inode);
+
+    if (socket->private.conn) {
+	netconn_delete(socket->private.conn);
+	socket->private.conn = NULL;
+    }
+    if (socket->private.buf) {
+	netbuf_delete(socket->private.buf);
+        socket->private.buf = NULL;
+    }
+}
+
+void tcp_fill_buffer(struct inode *inode)
+{
+    struct pxe_pvt_inode *socket = PVT(inode);
+    void *data;
+    u16_t len;
+    err_t err;
+
+    /* Clean up or advance an inuse netbuf */
+    if (socket->private.buf) {
+	if (netbuf_next(socket->private.buf) < 0) {
+	    netbuf_delete(socket->private.buf);
+	    socket->private.buf = NULL;
+	}
+    }
+    /* If needed get a new netbuf */
+    if (!socket->private.buf) {
+	err = netconn_recv(socket->private.conn, &(socket->private.buf));
+	if (!socket->private.buf || err) {
+	    socket->tftp_goteof = 1;
+	    if (inode->size == -1)
+		inode->size = socket->tftp_filepos;
+	    socket->ops->close(inode);
+	    return;
+	}
+    }
+    /* Report the current fragment of the netbuf */
+    err = netbuf_data(socket->private.buf, &data, &len);
+    if (err) {
+	printf("netbuf_data err: %d\n", err);
+	kaboom();
+    }
+    socket->tftp_dataptr = data;
+    socket->tftp_filepos += len;
+    socket->tftp_bytesleft = len;
+    return;
+}
+
+const struct pxe_conn_ops tcp_conn_ops = {
+    .fill_buffer	= tcp_fill_buffer,
+    .close		= tcp_close_file,
+};
diff --git a/core/fs/pxe/tftp.c b/core/fs/pxe/tftp.c
new file mode 100644
index 00000000..9b755c93
--- /dev/null
+++ b/core/fs/pxe/tftp.c
@@ -0,0 +1,443 @@
+#include <minmax.h>
+#include <net.h>
+#include "pxe.h"
+#include "url.h"
+#include "tftp.h"
+
+const uint8_t TimeoutTable[] = {
+    2, 2, 3, 3, 4, 5, 6, 7, 9, 10, 12, 15, 18, 21, 26, 31, 37, 44,
+    53, 64, 77, 92, 110, 132, 159, 191, 229, 255, 255, 255, 255, 0
+};
+struct tftp_options {
+    const char *str_ptr;        /* string pointer */
+    size_t      offset;		/* offset into socket structre */
+};
+struct tftp_packet {
+    uint16_t opcode;
+    uint16_t serial;
+    char data[];
+};
+
+#define IFIELD(x)	offsetof(struct inode, x)
+#define PFIELD(x)	(offsetof(struct inode, pvt) + \
+			 offsetof(struct pxe_pvt_inode, x))
+
+static const struct tftp_options tftp_options[] =
+{
+    { "tsize",   IFIELD(size) },
+    { "blksize", PFIELD(tftp_blksize) },
+};
+static const int tftp_nopts = sizeof tftp_options / sizeof tftp_options[0];
+
+static void tftp_error(struct inode *file, uint16_t errnum,
+		       const char *errstr);
+
+static void tftp_close_file(struct inode *inode)
+{
+    struct pxe_pvt_inode *socket = PVT(inode);
+    if (!socket->tftp_goteof) {
+	tftp_error(inode, 0, "No error, file close");
+    }
+    net_core_close(socket);
+}
+
+/**
+ * Send an ERROR packet.  This is used to terminate a connection.
+ *
+ * @inode:	Inode structure
+ * @errnum:	Error number (network byte order)
+ * @errstr:	Error string (included in packet)
+ */
+static void tftp_error(struct inode *inode, uint16_t errnum,
+		       const char *errstr)
+{
+    static struct {
+	uint16_t err_op;
+	uint16_t err_num;
+	char err_msg[64];
+    } __packed err_buf;
+    int len = min(strlen(errstr), sizeof(err_buf.err_msg)-1);
+    struct pxe_pvt_inode *socket = PVT(inode);
+
+    err_buf.err_op  = TFTP_ERROR;
+    err_buf.err_num = errnum;
+    memcpy(err_buf.err_msg, errstr, len);
+    err_buf.err_msg[len] = '\0';
+
+    net_core_send(socket, &err_buf, 4 + len + 1);
+}
+
+/**
+ * Send ACK packet. This is a common operation and so is worth canning.
+ *
+ * @param: inode,   Inode pointer
+ * @param: ack_num, Packet # to ack (host byte order)
+ *
+ */
+static void ack_packet(struct inode *inode, uint16_t ack_num)
+{
+    static uint16_t ack_packet_buf[2];
+    struct pxe_pvt_inode *socket = PVT(inode);
+
+    /* Packet number to ack */
+    ack_packet_buf[0]     = TFTP_ACK;
+    ack_packet_buf[1]     = htons(ack_num);
+
+    net_core_send(socket, ack_packet_buf, 4);
+}
+
+/*
+ * Get a fresh packet if the buffer is drained, and we haven't hit
+ * EOF yet.  The buffer should be filled immediately after draining!
+ */
+static void tftp_get_packet(struct inode *inode)
+{
+    uint16_t last_pkt;
+    const uint8_t *timeout_ptr;
+    uint8_t timeout;
+    uint16_t buffersize;
+    uint16_t serial;
+    jiffies_t oldtime;
+    struct tftp_packet *pkt = NULL;
+    uint16_t buf_len;
+    struct pxe_pvt_inode *socket = PVT(inode);
+    uint16_t src_port;
+    uint32_t src_ip;
+    int err;
+
+    /*
+     * Start by ACKing the previous packet; this should cause
+     * the next packet to be sent.
+     */
+    timeout_ptr = TimeoutTable;
+    timeout = *timeout_ptr++;
+    oldtime = jiffies();
+
+ ack_again:
+    ack_packet(inode, socket->tftp_lastpkt);
+
+    while (timeout) {
+	buf_len = socket->tftp_blksize + 4;
+	err = net_core_recv(socket, socket->tftp_pktbuf, &buf_len,
+			    &src_ip, &src_port);
+	if (err) {
+	    jiffies_t now = jiffies();
+
+	    if (now-oldtime >= timeout) {
+		oldtime = now;
+		timeout = *timeout_ptr++;
+		if (!timeout)
+		    break;
+		goto ack_again;
+	    }
+            continue;
+	}
+
+	if (buf_len < 4)	/* Bad size for a DATA packet */
+	    continue;
+
+        pkt = (struct tftp_packet *)(socket->tftp_pktbuf);
+        if (pkt->opcode != TFTP_DATA)    /* Not a data packet */
+            continue;
+
+        /* If goes here, recevie OK, break */
+        break;
+    }
+
+    /* time runs out */
+    if (timeout == 0)
+	kaboom();
+
+    last_pkt = socket->tftp_lastpkt;
+    last_pkt++;
+    serial = ntohs(pkt->serial);
+    if (serial != last_pkt) {
+        /*
+         * Wrong packet, ACK the packet and try again.
+         * This is presumably because the ACK got lost,
+         * so the server just resent the previous packet.
+         */
+#if 0
+	printf("Wrong packet, wanted %04x, got %04x\n", \
+               htons(last_pkt), htons(*(uint16_t *)(data+2)));
+#endif
+        goto ack_again;
+    }
+
+    /* It's the packet we want.  We're also EOF if the size < blocksize */
+    socket->tftp_lastpkt = last_pkt;    /* Update last packet number */
+    buffersize = buf_len - 4;		/* Skip TFTP header */
+    socket->tftp_dataptr = socket->tftp_pktbuf + 4;
+    socket->tftp_filepos += buffersize;
+    socket->tftp_bytesleft = buffersize;
+    if (buffersize < socket->tftp_blksize) {
+        /* it's the last block, ACK packet immediately */
+        ack_packet(inode, serial);
+
+        /* Make sure we know we are at end of file */
+        inode->size 		= socket->tftp_filepos;
+        socket->tftp_goteof	= 1;
+        tftp_close_file(inode);
+    }
+}
+
+const struct pxe_conn_ops tftp_conn_ops = {
+    .fill_buffer	= tftp_get_packet,
+    .close		= tftp_close_file,
+};
+
+/**
+ * Open a TFTP connection to the server
+ *
+ * @param:inode, the inode to store our state in
+ * @param:ip, the ip to contact to get the file
+ * @param:filename, the file we wanna open
+ *
+ * @out: open_file_t structure, stores in file->open_file
+ * @out: the lenght of this file, stores in file->file_len
+ *
+ */
+void tftp_open(struct url_info *url, int flags, struct inode *inode,
+	       const char **redir)
+{
+    struct pxe_pvt_inode *socket = PVT(inode);
+    char *buf;
+    uint16_t buf_len;
+    char *p;
+    char *options;
+    char *data;
+    static const char rrq_tail[] = "octet\0""tsize\0""0\0""blksize\0""1408";
+    char rrq_packet_buf[2+2*FILENAME_MAX+sizeof rrq_tail];
+    char reply_packet_buf[PKTBUF_SIZE];
+    const struct tftp_options *tftp_opt;
+    int i = 0;
+    int err;
+    int buffersize;
+    int rrq_len;
+    const uint8_t  *timeout_ptr;
+    jiffies_t timeout;
+    jiffies_t oldtime;
+    uint16_t opcode;
+    uint16_t blk_num;
+    uint32_t opdata, *opdata_ptr;
+    uint16_t src_port;
+    uint32_t src_ip;
+
+    (void)redir;		/* TFTP does not redirect */
+    (void)flags;
+
+    if (url->type != URL_OLD_TFTP) {
+	/*
+	 * The TFTP URL specification allows the TFTP to end with a
+	 * ;mode= which we just ignore.
+	 */
+	url_unescape(url->path, ';');
+    }
+
+    if (!url->port)
+	url->port = TFTP_PORT;
+
+    socket->ops = &tftp_conn_ops;
+    if (net_core_open(socket, NET_CORE_UDP))
+	return;
+
+    buf = rrq_packet_buf;
+    *(uint16_t *)buf = TFTP_RRQ;  /* TFTP opcode */
+    buf += 2;
+
+    buf = stpcpy(buf, url->path);
+
+    buf++;			/* Point *past* the final NULL */
+    memcpy(buf, rrq_tail, sizeof rrq_tail);
+    buf += sizeof rrq_tail;
+
+    rrq_len = buf - rrq_packet_buf;
+
+    timeout_ptr = TimeoutTable;   /* Reset timeout */
+sendreq:
+    net_core_disconnect(socket);
+    timeout = *timeout_ptr++;
+    if (!timeout)
+	return;			/* No file available... */
+    oldtime = jiffies();
+
+    net_core_connect(socket, url->ip, url->port);
+    net_core_send(socket, rrq_packet_buf, rrq_len);
+
+    /* If the WRITE call fails, we let the timeout take care of it... */
+wait_pkt:
+    net_core_disconnect(socket);
+    for (;;) {
+	buf_len = sizeof(reply_packet_buf);
+
+	err = net_core_recv(socket, reply_packet_buf, &buf_len,
+			    &src_ip, &src_port);
+	if (err) {
+	    jiffies_t now = jiffies();
+	    if (now - oldtime >= timeout)
+		 goto sendreq;
+	} else {
+	    /* Make sure the packet actually came from the server */
+	    if (src_ip == url->ip)
+		break;
+	}
+    }
+
+    net_core_disconnect(socket);
+    net_core_connect(socket, src_ip, src_port);
+
+    /* filesize <- -1 == unknown */
+    inode->size = -1;
+    socket->tftp_blksize = TFTP_BLOCKSIZE;
+    buffersize = buf_len - 2;	  /* bytes after opcode */
+    if (buffersize < 0)
+        goto wait_pkt;                     /* Garbled reply */
+
+    /*
+     * Get the opcode type, and parse it
+     */
+    opcode = *(uint16_t *)reply_packet_buf;
+    switch (opcode) {
+    case TFTP_ERROR:
+        inode->size = 0;
+	goto done;        /* ERROR reply; don't try again */
+
+    case TFTP_DATA:
+        /*
+         * If the server doesn't support any options, we'll get a
+         * DATA reply instead of OACK. Stash the data in the file
+         * buffer and go with the default value for all options...
+         *
+         * We got a DATA packet, meaning no options are
+         * suported. Save the data away and consider the
+         * length undefined, *unless* this is the only
+         * data packet...
+         */
+        buffersize -= 2;
+        if (buffersize < 0)
+            goto wait_pkt;
+        data = reply_packet_buf + 2;
+        blk_num = ntohs(*(uint16_t *)data);
+        data += 2;
+        if (blk_num != 1)
+            goto wait_pkt;
+        socket->tftp_lastpkt = blk_num;
+        if (buffersize > TFTP_BLOCKSIZE)
+            goto err_reply;	/* Corrupt */
+
+	socket->tftp_pktbuf = malloc(TFTP_BLOCKSIZE + 4);
+	if (!socket->tftp_pktbuf)
+	    goto err_reply;	/* Internal error */
+
+        if (buffersize < TFTP_BLOCKSIZE) {
+            /*
+             * This is the final EOF packet, already...
+             * We know the filesize, but we also want to
+             * ack the packet and set the EOF flag.
+             */
+            inode->size = buffersize;
+            socket->tftp_goteof = 1;
+            ack_packet(inode, blk_num);
+        }
+
+        socket->tftp_bytesleft = buffersize;
+        socket->tftp_dataptr = socket->tftp_pktbuf;
+        memcpy(socket->tftp_pktbuf, data, buffersize);
+	goto done;
+
+    case TFTP_OACK:
+        /*
+         * Now we need to parse the OACK packet to get the transfer
+         * and packet sizes.
+         */
+
+        options = reply_packet_buf + 2;
+	p = options;
+
+	while (buffersize) {
+	    const char *opt = p;
+
+	    /*
+	     * If we find an option which starts with a NUL byte,
+	     * (a null option), we're either seeing garbage that some
+	     * TFTP servers add to the end of the packet, or we have
+	     * no clue how to parse the rest of the packet (what is
+	     * an option name and what is a value?)  In either case,
+	     * discard the rest.
+	     */
+	    if (!*opt)
+		goto done;
+
+            while (buffersize) {
+                if (!*p)
+                    break;	/* Found a final null */
+                *p++ |= 0x20;
+		buffersize--;
+            }
+	    if (!buffersize)
+		break;		/* Unterminated option */
+
+	    /* Consume the terminal null */
+	    p++;
+	    buffersize--;
+
+	    if (!buffersize)
+		break;		/* No option data */
+
+            /*
+             * Parse option pointed to by options; guaranteed to be
+	     * null-terminated
+             */
+            tftp_opt = tftp_options;
+            for (i = 0; i < tftp_nopts; i++) {
+                if (!strcmp(opt, tftp_opt->str_ptr))
+                    break;
+                tftp_opt++;
+            }
+            if (i == tftp_nopts)
+                goto err_reply; /* Non-negotitated option returned,
+				   no idea what it means ...*/
+
+            /* get the address of the filed that we want to write on */
+            opdata_ptr = (uint32_t *)((char *)inode + tftp_opt->offset);
+	    opdata = 0;
+
+            /* do convert a number-string to decimal number, just like atoi */
+            while (buffersize--) {
+		uint8_t d = *p++;
+                if (d == '\0')
+                    break;              /* found a final null */
+		d -= '0';
+                if (d > 9)
+                    goto err_reply;     /* Not a decimal digit */
+                opdata = opdata*10 + d;
+            }
+	    *opdata_ptr = opdata;
+	}
+
+	if (socket->tftp_blksize < 64 || socket->tftp_blksize > PKTBUF_SIZE)
+	    goto err_reply;
+
+	/* Parsing successful, allocate buffer */
+	socket->tftp_pktbuf = malloc(socket->tftp_blksize + 4);
+	if (!socket->tftp_pktbuf)
+	    goto err_reply;
+	else
+	    goto done;
+
+    default:
+	printf("TFTP unknown opcode %d\n", ntohs(opcode));
+	goto err_reply;
+    }
+
+err_reply:
+    /* Build the TFTP error packet */
+    tftp_error(inode, TFTP_EOPTNEG, "TFTP protocol error");
+    inode->size = 0;
+
+done:
+    if (!inode->size)
+	net_core_close(socket);
+
+    return;
+}
diff --git a/core/fs/pxe/tftp.h b/core/fs/pxe/tftp.h
new file mode 100644
index 00000000..114c221f
--- /dev/null
+++ b/core/fs/pxe/tftp.h
@@ -0,0 +1,54 @@
+/* -----------------------------------------------------------------------
+ *
+ *   Copyright 1999-2008 H. Peter Anvin - All Rights Reserved
+ *   Copyright 2009-2011 Intel Corporation; author: H. Peter Anvin
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * tftp.h
+ */
+#ifndef PXE_TFTP_H
+#define PXE_TFTP_H
+
+/*
+ * TFTP default port number
+ */
+#define TFTP_PORT	 69
+
+/*
+ * TFTP default block size
+ */
+#define TFTP_BLOCKSIZE_LG2 9
+#define TFTP_BLOCKSIZE  (1 << TFTP_BLOCKSIZE_LG2)
+
+/*
+ * TFTP operation codes
+ */
+#define TFTP_RRQ	 htons(1)		// Read rest
+#define TFTP_WRQ	 htons(2)		// Write rest
+#define TFTP_DATA	 htons(3)		// Data packet
+#define TFTP_ACK	 htons(4)		// ACK packet
+#define TFTP_ERROR	 htons(5)		// ERROR packet
+#define TFTP_OACK	 htons(6)		// OACK packet
+
+/*
+ * TFTP error codes
+ */
+#define TFTP_EUNDEF	 htons(0)		// Unspecified error
+#define TFTP_ENOTFOUND	 htons(1)		// File not found
+#define TFTP_EACCESS	 htons(2)		// Access violation
+#define TFTP_ENOSPACE	 htons(3)		// Disk full
+#define TFTP_EBADOP	 htons(4)		// Invalid TFTP operation
+#define TFTP_EBADID	 htons(5)		// Unknown transfer
+#define TFTP_EEXISTS	 htons(6)		// File exists
+#define TFTP_ENOUSER	 htons(7)		// No such user
+#define TFTP_EOPTNEG	 htons(8)		// Option negotiation failure
+
+#endif /* PXE_TFTP_H */
diff --git a/core/fs/pxe/url.h b/core/fs/pxe/url.h
new file mode 100644
index 00000000..53984f3a
--- /dev/null
+++ b/core/fs/pxe/url.h
@@ -0,0 +1,33 @@
+/*
+ * url.h
+ */
+
+#ifndef CORE_PXE_URL_H
+#define CORE_PXE_URL_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+enum url_type {
+    URL_NORMAL,			/* It is a full URL */
+    URL_OLD_TFTP,		/* It's a ::-style TFTP path */
+    URL_SUFFIX			/* Prepend the pathname prefix */
+};
+
+struct url_info {
+    char *scheme;
+    char *user;
+    char *passwd;
+    char *host;
+    uint32_t ip;		/* Placeholder field not set by parse_url() */
+    unsigned int port;
+    char *path;			/* Includes query */
+    enum url_type type;
+};
+
+enum url_type url_type(const char *url);
+void parse_url(struct url_info *ui, char *url);
+size_t url_escape_unsafe(char *output, const char *input, size_t bufsize);
+char *url_unescape(char *buffer, char terminator);
+
+#endif /* CORE_PXE_URL_H */
diff --git a/core/fs/pxe/urlparse.c b/core/fs/pxe/urlparse.c
new file mode 100644
index 00000000..6b73ddb6
--- /dev/null
+++ b/core/fs/pxe/urlparse.c
@@ -0,0 +1,223 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2009-2011 Intel Corporation; author: H. Peter Anvin
+ *
+ *   Permission is hereby granted, free of charge, to any person
+ *   obtaining a copy of this software and associated documentation
+ *   files (the "Software"), to deal in the Software without
+ *   restriction, including without limitation the rights to use,
+ *   copy, modify, merge, publish, distribute, sublicense, and/or
+ *   sell copies of the Software, and to permit persons to whom
+ *   the Software is furnished to do so, subject to the following
+ *   conditions:
+ *
+ *   The above copyright notice and this permission notice shall
+ *   be included in all copies or substantial portions of the Software.
+ *
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ *   OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * urlparse.c
+ */
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include "url.h"
+
+/*
+ * Return the type of a URL without modifying the string
+ */
+enum url_type url_type(const char *url)
+{
+    const char *q;
+
+    q = strchr(url, ':');
+    if (!q)
+	return URL_SUFFIX;
+
+    if (q[1] == '/' && q[2] == '/')
+	return URL_NORMAL;
+
+    if (q[1] == ':')
+	return URL_OLD_TFTP;
+
+    return URL_SUFFIX;
+}
+
+/*
+ * Decompose a URL into its components.  This is done in-place;
+ * this routine does not allocate any additional storage.  Freeing the
+ * original buffer frees all storage used.
+ */
+void parse_url(struct url_info *ui, char *url)
+{
+    char *p = url;
+    char *q, *r, *s;
+    int c;
+
+    memset(ui, 0, sizeof *ui);
+
+    q = strchr(p, ':');
+    if (q && (q[1] == '/' && q[2] == '/')) {
+	ui->type = URL_NORMAL;
+	
+	ui->scheme = p;
+	*q = '\0';
+	p = q+3;
+	
+	q = strchr(p, '/');
+	if (q) {
+	    *q = '\0';
+	    ui->path = q+1;
+	    q = strchr(q+1, '#');
+	    if (q)
+		*q = '\0';
+	} else {
+	    ui->path = "";
+	}
+	
+	r = strchr(p, '@');
+	if (r) {
+	    ui->user = p;
+	    *r = '\0';
+	    s = strchr(p, ':');
+	    if (s) {
+		*s = '\0';
+		ui->passwd = s+1;
+	    }
+	    p = r+1;
+	}
+	
+	ui->host = p;
+	r = strchr(p, ':');
+	if (r) {
+	    *r++ = '\0';
+	    ui->port = 0;
+	    while ((c = *r++)) {
+		c -= '0';
+		if (c > 9)
+		    break;
+		ui->port = ui->port * 10 + c;
+	    }
+	}
+    } else if (q && q[1] == ':') {
+	*q = '\0';
+	ui->scheme = "tftp";
+	ui->host = p;
+	ui->path = q+2;
+	ui->type = URL_OLD_TFTP;
+    } else {
+	ui->path = p;
+	ui->type = URL_SUFFIX;
+    }
+}
+
+/*
+ * Escapes unsafe characters in a URL.
+ * This does *not* escape things like query characters!
+ * Returns the number of characters in the total output.
+ */
+size_t url_escape_unsafe(char *output, const char *input, size_t bufsize)
+{
+    static const char uchexchar[] = "0123456789ABCDEF";
+    const char *p;
+    unsigned char c;
+    char *q;
+    size_t n = 0;
+
+    q = output;
+    for (p = input; (c = *p); p++) {
+	if (c <= ' ' || c > '~') {
+	    if (++n < bufsize) *q++ = '%';
+	    if (++n < bufsize) *q++ = uchexchar[c >> 4];
+	    if (++n < bufsize) *q++ = uchexchar[c & 15];
+	} else {
+	    if (++n < bufsize) *q++ = c;
+	}
+    }
+
+    *q = '\0';
+    return n;
+}
+
+static int hexdigit(char c)
+{
+    if (c >= '0' && c <= '9')
+	return c - '0';
+    c |= 0x20;
+    if (c >= 'a' && c <= 'f')
+	return c - 'a' + 10;
+    return -1;
+}
+
+/*
+ * Unescapes a buffer, optionally ending at an *unescaped* terminator
+ * (like ; for TFTP).  The unescaping is done in-place.
+ *
+ * If a terminator is reached, return a pointer to the first character
+ * after the terminator.
+ */
+char *url_unescape(char *buffer, char terminator)
+{
+    char *p = buffer;
+    char *q = buffer;
+    unsigned char c;
+    int x, y;
+
+    while ((c = *p)) {
+	if (c == terminator) {
+	    *q = '\0';
+	    return p;
+	}
+	p++;
+	if (c == '%') {
+	    x = hexdigit(p[0]);
+	    if (x >= 0) {
+		y = hexdigit(p[1]);
+		if (y >= 0) {
+		    *q++ = (x << 4) + y;
+		    p += 2;
+		    continue;
+		}
+	    }
+	}
+	*q++ = c;
+    }
+    *q = '\0';
+    return NULL;
+}
+
+#ifdef URL_TEST
+
+int main(int argc, char *argv[])
+{
+    int i;
+    struct url_info url;
+
+    for (i = 1; i < argc; i++) {
+	parse_url(&url, argv[i]);
+	printf("scheme:  %s\n"
+	       "user:    %s\n"
+	       "passwd:  %s\n"
+	       "host:    %s\n"
+	       "port:    %d\n"
+	       "path:    %s\n"
+	       "type:    %d\n",
+	       url.scheme, url.user, url.passwd, url.host, url.port,
+	       url.path, url.type);
+    }
+
+    return 0;
+}
+
+#endif
diff --git a/core/fs/readdir.c b/core/fs/readdir.c
index e2d593fc..546a704a 100644
--- a/core/fs/readdir.c
+++ b/core/fs/readdir.c
@@ -1,3 +1,4 @@
+#include <fcntl.h>
 #include <stdio.h>
 #include <string.h>
 #include <sys/dirent.h>
@@ -12,7 +13,7 @@ __export DIR *opendir(const char *path)
     int rv;
     struct file *file;
 
-    rv = searchdir(path);
+    rv = searchdir(path, O_RDONLY|O_DIRECTORY);
     if (rv < 0)
 	return NULL;
 
diff --git a/core/head.inc b/core/head.inc
index 71eb5744..286b9b4e 100644
--- a/core/head.inc
+++ b/core/head.inc
@@ -34,5 +34,6 @@
 %include "tracers.inc"
 %include "stack.inc"
 %include "io.inc"
+%include "vkernel.inc"
 
 %endif ; _HEAD_INC
diff --git a/core/idle.c b/core/idle.c
index 9514df88..a089b088 100644
--- a/core/idle.c
+++ b/core/idle.c
@@ -1,5 +1,5 @@
-/* -*- fundamental -*- ---------------------------------------------------
- *
+/* ----------------------------------------------------------------------- *
+ *   
  *   Copyright 2008 H. Peter Anvin - All Rights Reserved
  *   Copyright 2009-2010 Intel Corporation; author: H. Peter Anvin
  *
@@ -24,7 +24,7 @@
 
 #define TICKS_TO_IDLE	4	/* Also in idle.inc */
 
-extern uint32_t _IdleTimer;
+extern jiffies_t _IdleTimer;
 __export uint16_t NoHalt = 0;
 
 int (*idle_hook_func)(void);
diff --git a/core/include/core.h b/core/include/core.h
index d54495bb..d35bd038 100644
--- a/core/include/core.h
+++ b/core/include/core.h
@@ -11,6 +11,9 @@
 #include <com32.h>
 #include <errno.h>
 #include <syslinux/pmapi.h>
+#include <syslinux/sysappend.h>
+#include <kaboom.h>
+#include <timer.h>
 
 extern char core_xfer_buf[65536];
 extern char core_cache_buf[65536];
@@ -42,6 +45,10 @@ extern uint8_t FlowIgnore;
 /* diskstart.inc isolinux.asm*/
 extern void getlinsec(void);
 
+/* pm.inc */
+void core_pm_null_hook(void);
+extern void (*core_pm_hook)(void);
+
 /* getc.inc */
 extern void core_open(void);
 
@@ -60,6 +67,12 @@ extern void *zalloc(size_t);
 extern void free(void *);
 extern void mem_init(void);
 
+/* sysappend.c */
+extern void print_sysappend(void);
+extern const char *sysappend_strings[SYSAPPEND_MAX];
+extern uint32_t SysAppends;
+extern void sysappend_set_uuid(const uint8_t *uuid);
+
 void __cdecl core_intcall(uint8_t, const com32sys_t *, com32sys_t *);
 void __cdecl core_farcall(uint32_t, const com32sys_t *, com32sys_t *);
 int __cdecl core_cfarcall(uint32_t, const void *, uint32_t);
@@ -74,31 +87,6 @@ void call16(void (*)(void), const com32sys_t *, com32sys_t *);
 #define __bss16  __attribute__((nocommon,section(".bss16")))
 
 /*
- * Section for very large aligned objects, not zeroed on startup
- */
-#define __hugebss __attribute__((nocommon,section(".hugebss"),aligned(4096)))
-
-/*
- * Death!  The macro trick is to avoid symbol conflict with
- * the real-mode symbol kaboom.
- */
-__noreturn _kaboom(void);
-#define kaboom() _kaboom()
-
-/*
- * Basic timer function...
- */
-extern volatile uint32_t __jiffies, __ms_timer;
-static inline uint32_t jiffies(void)
-{
-    return __jiffies;
-}
-static inline uint32_t ms_timer(void)
-{
-    return __ms_timer;
-}
-
-/*
  * Helper routine to return a specific set of flags
  */
 static inline void set_flags(com32sys_t *regs, uint32_t flags)
@@ -125,7 +113,11 @@ extern void cleanup_hardware(void);
 extern void sirq_cleanup(void);
 extern void adjust_screen(void);
 
-extern void execute(const char *cmdline, uint32_t type);
+extern void execute(const char *cmdline, uint32_t type, bool sysappend);
 extern void load_kernel(const char *cmdline);
 
+extern void dmi_init(void);
+
+extern void do_sysappend(char *buf);
+
 #endif /* CORE_H */
diff --git a/core/include/ctype.h b/core/include/ctype.h
index 048a77d6..6c7f57f4 100644
--- a/core/include/ctype.h
+++ b/core/include/ctype.h
@@ -22,9 +22,17 @@ static inline int tolower(int c)
     return c;
 }
 
-static inline int isspace(int c)
+static inline int isspace(int ch)
 {
-	return c <= ' ';
+    int space = 0;
+    if ((ch == ' ') ||
+	(ch == '\f') ||
+	(ch == '\n') ||
+	(ch == '\r') ||
+	(ch == '\t') ||
+	(ch == '\v'))
+	space = 1;
+    return space;
 }
 
 #endif /* CTYPE_H */
diff --git a/core/include/fs.h b/core/include/fs.h
index 5c13f5b5..c7d0fd75 100644
--- a/core/include/fs.h
+++ b/core/include/fs.h
@@ -12,12 +12,9 @@
 #include "disk.h"
 
 /*
- * Maximum number of open files.  This is *currently* constrained by the
- * fact that PXE needs to be able to fit all its packet buffers into a
- * 64K segment; this should be fixed by moving the packet buffers to high
- * memory.
+ * Maximum number of open files.
  */
-#define MAX_OPEN_LG2	5
+#define MAX_OPEN_LG2	7
 #define MAX_OPEN	(1 << MAX_OPEN_LG2)
 
 #define FILENAME_MAX_LG2 8
@@ -56,7 +53,7 @@ struct fs_ops {
     enum fs_flags fs_flags;
     
     int      (*fs_init)(struct fs_info *);
-    void     (*searchdir)(const char *, struct file *);
+    void     (*searchdir)(const char *, int, struct file *);
     uint32_t (*getfssec)(struct file *, char *, int, bool *);
     void     (*close_file)(struct file *);
     void     (*mangle_name)(char *, const char *);
@@ -191,10 +188,10 @@ extern char *PATH;
 void pm_mangle_name(com32sys_t *);
 void pm_searchdir(com32sys_t *);
 void mangle_name(char *, const char *);
-int searchdir(const char *name);
+int searchdir(const char *name, int flags);
 void _close_file(struct file *);
 size_t pmapi_read_file(uint16_t *handle, void *buf, size_t sectors);
-int open_file(const char *name, struct com32_filedata *filedata);
+int open_file(const char *name, int flags, struct com32_filedata *filedata);
 void pm_open_file(com32sys_t *);
 void close_file(uint16_t handle);
 void pm_close_file(com32sys_t *);
diff --git a/core/include/kaboom.h b/core/include/kaboom.h
new file mode 100644
index 00000000..4a763be9
--- /dev/null
+++ b/core/include/kaboom.h
@@ -0,0 +1,11 @@
+#ifndef KABOOM_H
+#define KABOOM_H
+
+/*
+ * Death!  The macro trick is to avoid symbol conflict with
+ * the real-mode symbol kaboom.
+ */
+__noreturn _kaboom(void);
+#define kaboom() _kaboom()
+
+#endif /* KABOOM_H */
diff --git a/core/include/mbox.h b/core/include/mbox.h
new file mode 100644
index 00000000..3c35ce4e
--- /dev/null
+++ b/core/include/mbox.h
@@ -0,0 +1,59 @@
+/*
+ * mbox.h
+ *
+ * Simple thread mailbox interface
+ */
+
+#ifndef _MBOX_H
+#define _MBOX_H
+
+#include "thread.h"
+
+/*
+ * If a mailbox is allocated statically (as a struct mailbox), this
+ * is the number of slots it gets.
+ */
+#define MAILBOX_STATIC_SIZE	512
+
+struct mailbox {
+    struct semaphore prod_sem;	/* Producer semaphore (empty slots) */
+    struct semaphore cons_sem;	/* Consumer semaphore (data slots) */
+    struct semaphore head_sem;	/* Head pointer semaphore */
+    struct semaphore tail_sem;	/* Tail pointer semaphore */
+    void **wrap;		/* Where pointers wrap */
+    void **head;		/* Head pointer */
+    void **tail;		/* Tail pointer */
+
+    void *data[MAILBOX_STATIC_SIZE]; /* Data array */
+};
+
+/* The number of bytes for an mailbox of size s */
+#define MBOX_BYTES(s) (sizeof(struct mailbox) + \
+		       ((s)-MAILBOX_STATIC_SIZE)*sizeof(void *))
+
+void mbox_init(struct mailbox *mbox, size_t size);
+int mbox_post(struct mailbox *mbox, void *msg, mstime_t timeout);
+mstime_t mbox_fetch(struct mailbox *mbox, void **msg, mstime_t timeout);
+
+/*
+ * This marks a mailbox object as unusable; it will remain unusable
+ * until sem_init() is called on it again.  This DOES NOT clear the
+ * list of blocked processes on this mailbox!
+ *
+ * It is also possible to mark the mailbox invalid by zeroing its
+ * memory structure.
+ */
+static inline void mbox_set_invalid(struct mailbox *mbox)
+{
+    sem_set_invalid(&mbox->prod_sem);
+}
+
+/*
+ * Ask if a mailbox object has been initialized.
+ */
+static inline bool mbox_is_valid(struct mailbox *mbox)
+{
+    return sem_is_valid(&mbox->prod_sem);
+}
+
+#endif /* _MBOX_H */
diff --git a/core/include/net.h b/core/include/net.h
new file mode 100644
index 00000000..4f6819f9
--- /dev/null
+++ b/core/include/net.h
@@ -0,0 +1,33 @@
+#ifndef _NET_H
+#define _NET_H
+
+#include <stdint.h>
+#include <stddef.h>
+
+/* Protocol family */
+enum net_core_proto {
+    NET_CORE_TCP,
+    NET_CORE_UDP,
+};
+
+void net_core_init(void);
+
+struct pxe_pvt_inode;
+
+int net_core_open(struct pxe_pvt_inode *socket, enum net_core_proto proto);
+void net_core_close(struct pxe_pvt_inode *socket);
+
+void net_core_connect(struct pxe_pvt_inode *socket,
+		      uint32_t ip, uint16_t port);
+void net_core_disconnect(struct pxe_pvt_inode *socket);
+
+int net_core_recv(struct pxe_pvt_inode *socket, void *buf, uint16_t *buf_len,
+		  uint32_t *src_ip, uint16_t *src_port);
+
+void net_core_send(struct pxe_pvt_inode *socket,
+		   const void *data, size_t len);
+
+void probe_undi(void);
+void pxe_init_isr(void);
+
+#endif /* _NET_H */
diff --git a/core/include/thread.h b/core/include/thread.h
new file mode 100644
index 00000000..6bfdfaa7
--- /dev/null
+++ b/core/include/thread.h
@@ -0,0 +1,115 @@
+#ifndef _THREAD_H
+#define _THREAD_H
+
+#include <stddef.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <timer.h>
+#include <sys/cpu.h>
+
+/* The idle thread runs at this priority */
+#define IDLE_THREAD_PRIORITY	INT_MAX
+
+/* This priority should normally be used for hardware-polling threads */
+#define POLL_THREAD_PRIORITY	(INT_MAX-1)
+
+struct semaphore;
+
+struct thread_list {
+    struct thread_list *next, *prev;
+};
+
+/*
+ * Stack frame used by __switch_to, see thread_asm.S
+ */
+struct thread_stack {
+    int errno;
+    uint16_t rmsp, rmss;
+    uint32_t edi, esi, ebp, ebx;
+    void (*eip)(void);
+};
+
+struct thread_block {
+    struct thread_list list;
+    struct thread *thread;
+    struct semaphore *semaphore;
+    mstime_t block_time;
+    mstime_t timeout;
+    bool timed_out;
+};
+
+#define THREAD_MAGIC 0x3568eb7d
+
+struct thread {
+    struct thread_stack *esp;	/* Must be first; stack pointer */
+    unsigned int thread_magic;
+    const char *name;		/* Name (for debugging) */
+    struct thread_list  list;
+    struct thread_block *blocked;
+    void *stack, *rmstack;	/* Stacks, iff allocated by malloc/lmalloc */
+    void *pvt; 			/* For the benefit of lwIP */
+    int prio;
+};
+
+extern void (*sched_hook_func)(void);
+
+void __thread_process_timeouts(void);
+void __schedule(void);
+void __switch_to(struct thread *);
+void thread_yield(void);
+
+extern struct thread *__current;
+static inline struct thread *current(void)
+{
+    return __current;
+}
+
+struct semaphore {
+    int count;
+    struct thread_list list;
+};
+
+#define DECLARE_INIT_SEMAPHORE(sem, cnt)	\
+    struct semaphore sem = {			\
+	.count = (cnt),				\
+	.list =	{				\
+            .next = &sem.list,			\
+            .prev = &sem.list                   \
+        }					\
+    }
+
+mstime_t sem_down(struct semaphore *, mstime_t);
+void sem_up(struct semaphore *);
+void sem_init(struct semaphore *, int);
+
+/*
+ * This marks a semaphore object as unusable; it will remain unusable
+ * until sem_init() is called on it again.  This DOES NOT clear the
+ * list of blocked processes on this semaphore!
+ *
+ * It is also possible to mark the semaphore invalid by zeroing its
+ * memory structure.
+ */
+static inline void sem_set_invalid(struct semaphore *sem)
+{
+    sem->list.next = NULL;
+}
+
+/*
+ * Ask if a semaphore object has been initialized.
+ */
+static inline bool sem_is_valid(struct semaphore *sem)
+{
+    return !!sem->list.next;
+}
+
+struct thread *start_thread(const char *name, size_t stack_size, int prio,
+			    void (*start_func)(void *), void *func_arg);
+void __exit_thread(void);
+void kill_thread(struct thread *);
+
+void start_idle_thread(void);
+void test_thread(void);
+
+#endif /* _THREAD_H */
diff --git a/core/include/timer.h b/core/include/timer.h
new file mode 100644
index 00000000..1d66ba73
--- /dev/null
+++ b/core/include/timer.h
@@ -0,0 +1,21 @@
+#ifndef TIMER_H
+#define TIMER_H
+
+/*
+ * Basic timer function...
+ */
+typedef uint32_t jiffies_t;
+extern volatile jiffies_t __jiffies, __ms_timer;
+static inline jiffies_t jiffies(void)
+{
+    return __jiffies;
+}
+
+typedef uint32_t mstime_t;
+typedef int32_t  mstimediff_t;
+static inline mstime_t ms_timer(void)
+{
+    return __ms_timer;
+}
+
+#endif /* TIMER_H */
diff --git a/core/init.c b/core/init.c
index ab2e271d..85bab775 100644
--- a/core/init.c
+++ b/core/init.c
@@ -77,6 +77,14 @@ void init(com32sys_t *regs __unused)
 
 	adjust_screen();
 
+	/* Init the memory subsystem */
+	mem_init();
+
 	/* CPU-dependent initialization and related checks. */
 	check_escapes();
+
+	/*
+	 * Scan the DMI tables for interesting information.
+	 */
+	dmi_init();
 }
diff --git a/core/isolinux.asm b/core/isolinux.asm
index b292d8f9..b494eb4d 100644
--- a/core/isolinux.asm
+++ b/core/isolinux.asm
@@ -35,23 +35,6 @@ SECTOR_SIZE	equ (1 << SECTOR_SHIFT)
 
 ROOT_DIR_WORD	equ 0x002F
 
-;
-; The following structure is used for "virtual kernels"; i.e. LILO-style
-; option labels.  The options we permit here are `kernel' and `append
-; Since there is no room in the bottom 64K for all of these, we
-; stick them in high memory and copy them down before we need them.
-;
-		struc vkernel
-vk_vname:	resb FILENAME_MAX	; Virtual name **MUST BE FIRST!**
-vk_rname:	resb FILENAME_MAX	; Real name
-vk_appendlen:	resw 1
-vk_type:	resb 1			; Type of file
-		alignb 4
-vk_append:	resb max_cmd_len+1	; Command line
-		alignb 4
-vk_end:		equ $			; Should be <= vk_size
-		endstruc
-
 ; ---------------------------------------------------------------------------
 ;   BEGIN CODE
 ; ---------------------------------------------------------------------------
@@ -1213,17 +1196,6 @@ FuncFlag	resb 1			; Escape sequences received from keyboard
 KernelType	resb 1			; Kernel type, from vkernel, if known
 		global KernelName
 KernelName	resb FILENAME_MAX	; Mangled name for kernel
-		section .data16
-		global IPAppends, numIPAppends
-%if IS_PXELINUX
-		extern IPOption
-		alignz 2
-IPAppends	dw IPOption
-numIPAppends	equ ($-IPAppends)/2
-%else
-IPAppends	equ 0
-numIPAppends	equ 0
-%endif
 
 		section .text16
 ;
diff --git a/core/keywords b/core/keywords
index 7f585b48..8af0095f 100644
--- a/core/keywords
+++ b/core/keywords
@@ -34,6 +34,8 @@ onerror
 noescape
 nocomplete
 nohalt
+sysappend
+sendcookies
 f0
 f1
 f2
diff --git a/core/keywords.inc b/core/keywords.inc
index 08d77c64..d91ca4ff 100644
--- a/core/keywords.inc
+++ b/core/keywords.inc
@@ -92,9 +92,11 @@ keywd_table:
 		keyword f0,		pc_filename,	FKeyN(10)
 		keyword f11,		pc_filename,	FKeyN(11)
 		keyword f12,		pc_filename,	FKeyN(12)
+		keyword ipappend,	pc_sysappend
+		keyword sysappend,	pc_sysappend
+		keyword localboot,	pc_localboot
 %if IS_PXELINUX
-		keyword ipappend,	pc_ipappend
+		keyword sendcookies,	pc_sendcookies
 %endif
-		keyword localboot,	pc_localboot
 
 keywd_count	equ ($-keywd_table)/keywd_size
diff --git a/core/layout.inc b/core/layout.inc
index be797ede..53ca783d 100644
--- a/core/layout.inc
+++ b/core/layout.inc
@@ -65,6 +65,7 @@ STACK32_LEN	equ 64*1024
 		section .config		write progbits align=4
 		section .replacestub	exec write progbits align=16
 		section .gentextnr	exec write nobits align=16
+		section .stack16	write nobits align=16
 
 		; Use .bss16 for things that doesn't have to be in low memory;
 		; .earlybss should be used for things that absolutely have
diff --git a/core/legacynet/core.c b/core/legacynet/core.c
new file mode 100644
index 00000000..2163c693
--- /dev/null
+++ b/core/legacynet/core.c
@@ -0,0 +1,186 @@
+#include <syslinux/pxe_api.h>
+#include <com32.h>
+#include <core.h>
+#include <net.h>
+#include <pxe.h>
+#include <minmax.h>
+
+/* Common receive buffer */
+static __lowmem char packet_buf[PKTBUF_SIZE] __aligned(16);
+
+extern uint16_t get_port(void);
+extern void free_port(uint16_t);
+
+/**
+ * Open a socket
+ *
+ * @param:socket, the socket to open
+ * @param:proto, the protocol of the new connection
+ *
+ * @out: error code, 0 on success, -1 on failure
+ */
+int net_core_open(struct pxe_pvt_inode *socket __unused,
+		  enum net_core_proto proto)
+{
+    struct net_private *priv = &socket->private;
+
+    /* The legacy stack only supports UDP */
+    if (proto != NET_CORE_UDP)
+	return -1;
+
+    /* Allocate local UDP port number */
+    priv->tftp_localport = get_port();
+
+    return 0;
+}
+
+/**
+ * Close a socket
+ *
+ * @param:socket, the socket to open
+ */
+void net_core_close(struct pxe_pvt_inode *socket)
+{
+    struct net_private *priv = &socket->private;
+
+    if (priv->tftp_localport)
+	free_port(priv->tftp_localport);
+}
+
+/**
+ * Establish a connection on an open socket
+ *
+ * @param:socket, the open socket
+ * @param:ip, the ip address
+ * @param:port, the port number, host-byte order
+ */
+void net_core_connect(struct pxe_pvt_inode *socket, uint32_t ip,
+		      uint16_t port)
+{
+    struct net_private *priv = &socket->private;
+
+    socket->tftp_remoteport = htons(port);
+    priv->tftp_remoteip = ip;
+
+}
+
+/**
+ * Tear down a connection on an open socket
+ *
+ * @param:socket, the open socket
+ */
+void net_core_disconnect(struct pxe_pvt_inode *socket __unused)
+{
+}
+
+/**
+ * Read data from the network stack
+ *
+ * @param:socket, the open socket
+ * @param:buf, location of buffer to store data
+ * @param:buf_len, size of buffer
+
+ * @out: src_ip, ip address of the data source
+ * @out: src_port, port number of the data source, host-byte order
+ */
+int net_core_recv(struct pxe_pvt_inode *socket, void *buf, uint16_t *buf_len,
+		  uint32_t *src_ip, uint16_t *src_port)
+{
+    static __lowmem struct s_PXENV_UDP_READ  udp_read;
+    struct net_private *priv = &socket->private;
+    uint16_t bytes;
+    int err;
+
+    udp_read.status      = 0;
+    udp_read.buffer      = FAR_PTR(packet_buf);
+    udp_read.buffer_size = PKTBUF_SIZE;
+    udp_read.dest_ip     = IPInfo.myip;
+    udp_read.d_port      = priv->tftp_localport;
+
+    err = pxe_call(PXENV_UDP_READ, &udp_read);
+    if (err)
+	return err;
+
+    if (udp_read.status)
+	return udp_read.status;
+
+    bytes = min(udp_read.buffer_size, *buf_len);
+    memcpy(buf, packet_buf, bytes);
+
+    *src_ip = udp_read.src_ip;
+    *src_port = ntohs(udp_read.s_port);
+    *buf_len = bytes;
+
+    return 0;
+}
+
+/**
+ * Send a UDP packet.
+ *
+ * @param:socket, the open socket
+ * @param:data, data buffer to send
+ * @param:len, size of data bufer
+ */
+void net_core_send(struct pxe_pvt_inode *socket, const void *data, size_t len)
+{
+    static __lowmem struct s_PXENV_UDP_WRITE udp_write;
+    struct net_private *priv = &socket->private;
+    void *lbuf;
+    uint16_t tid;
+
+    lbuf = lmalloc(len);
+    if (!lbuf)
+	return;
+
+    memcpy(lbuf, data, len);
+
+    tid = priv->tftp_localport;   /* TID(local port No) */
+    udp_write.buffer    = FAR_PTR(lbuf);
+    udp_write.ip        = priv->tftp_remoteip;
+    udp_write.gw        = gateway(udp_write.ip);
+    udp_write.src_port  = tid;
+    udp_write.dst_port  = socket->tftp_remoteport;
+    udp_write.buffer_size = len;
+
+    pxe_call(PXENV_UDP_WRITE, &udp_write);
+
+    lfree(lbuf);
+}
+
+/**
+ * Network stack-specific initialization
+ *
+ * Initialize UDP stack
+ */
+void net_core_init(void)
+{
+    int err;
+    static __lowmem struct s_PXENV_UDP_OPEN udp_open;
+    udp_open.src_ip = IPInfo.myip;
+    err = pxe_call(PXENV_UDP_OPEN, &udp_open);
+    if (err || udp_open.status) {
+        printf("Failed to initialize UDP stack ");
+        printf("%d\n", udp_open.status);
+	kaboom();
+    }
+}
+
+void probe_undi(void)
+{
+}
+
+void pxe_init_isr(void)
+{
+}
+
+int reset_pxe(void)
+{
+    static __lowmem struct s_PXENV_UDP_CLOSE udp_close;
+    int err = 0;
+
+    pxe_idle_cleanup();
+
+    pxe_call(PXENV_UDP_CLOSE, &udp_close);
+
+    return err;
+}
diff --git a/core/legacynet/dnsresolv.c b/core/legacynet/dnsresolv.c
new file mode 100644
index 00000000..fab36aef
--- /dev/null
+++ b/core/legacynet/dnsresolv.c
@@ -0,0 +1,353 @@
+#include <stdio.h>
+#include <string.h>
+#include <core.h>
+#include "pxe.h"
+
+/* DNS CLASS values we care about */
+#define CLASS_IN	1
+
+/* DNS TYPE values we care about */
+#define TYPE_A		1
+#define TYPE_CNAME	5
+
+/*
+ * The DNS header structure
+ */
+struct dnshdr {
+    uint16_t id;
+    uint16_t flags;
+    /* number of entries in the question section */
+    uint16_t qdcount;
+    /* number of resource records in the answer section */
+    uint16_t ancount;
+    /* number of name server resource records in the authority records section*/
+    uint16_t nscount;
+    /* number of resource records in the additional records section */
+    uint16_t arcount;
+} __attribute__ ((packed));
+
+/*
+ * The DNS query structure
+ */
+struct dnsquery {
+    uint16_t qtype;
+    uint16_t qclass;
+} __attribute__ ((packed));
+
+/*
+ * The DNS Resource recodes structure
+ */
+struct dnsrr {
+    uint16_t type;
+    uint16_t class;
+    uint32_t ttl;
+    uint16_t rdlength;   /* The lenght of this rr data */
+    char     rdata[];
+} __attribute__ ((packed));
+
+
+#define DNS_PORT	htons(53)               /* Default DNS port */
+#define DNS_MAX_SERVERS 4		/* Max no of DNS servers */
+
+uint32_t dns_server[DNS_MAX_SERVERS] = {0, };
+
+
+/*
+ * Turn a string in _src_ into a DNS "label set" in _dst_; returns the
+ * number of dots encountered. On return, *dst is updated.
+ */
+int dns_mangle(char **dst, const char *p)
+{
+    char *q = *dst;
+    char *count_ptr;
+    char c;
+    int dots = 0;
+
+    count_ptr = q;
+    *q++ = 0;
+
+    while (1) {
+        c = *p++;
+        if (c == 0 || c == ':' || c == '/')
+            break;
+        if (c == '.') {
+            dots++;
+            count_ptr = q;
+            *q++ = 0;
+            continue;
+        }
+
+        *count_ptr += 1;
+        *q++ = c;
+    }
+
+    if (*count_ptr)
+        *q++ = 0;
+
+    /* update the strings */
+    *dst = q;
+    return dots;
+}
+
+
+/*
+ * Compare two sets of DNS labels, in _s1_ and _s2_; the one in _s2_
+ * is allowed pointers relative to a packet in buf.
+ *
+ */
+static bool dns_compare(const void *s1, const void *s2, const void *buf)
+{
+    const uint8_t *q = s1;
+    const uint8_t *p = s2;
+    unsigned int c0, c1;
+
+    while (1) {
+	c0 = p[0];
+        if (c0 >= 0xc0) {
+	    /* Follow pointer */
+	    c1 = p[1];
+	    p = (const uint8_t *)buf + ((c0 - 0xc0) << 8) + c1;
+	} else if (c0) {
+	    c0++;		/* Include the length byte */
+	    if (memcmp(q, p, c0))
+		return false;
+	    q += c0;
+	    p += c0;
+	} else {
+	    return *q == 0;
+	}
+    }
+}
+
+/*
+ * Copy a DNS label into a buffer, considering the possibility that we might
+ * have to follow pointers relative to "buf".
+ * Returns a pointer to the first free byte *after* the terminal null.
+ */
+static void *dns_copylabel(void *dst, const void *src, const void *buf)
+{
+    uint8_t *q = dst;
+    const uint8_t *p = src;
+    unsigned int c0, c1;
+
+    while (1) {
+	c0 = p[0];
+        if (c0 >= 0xc0) {
+	    /* Follow pointer */
+	    c1 = p[1];
+	    p = (const uint8_t *)buf + ((c0 - 0xc0) << 8) + c1;
+	} else if (c0) {
+	    c0++;		/* Include the length byte */
+	    memcpy(q, p, c0);
+	    p += c0;
+	    q += c0;
+	} else {
+	    *q++ = 0;
+	    return q;
+	}
+    }
+}
+
+/*
+ * Skip past a DNS label set in DS:SI
+ */
+static char *dns_skiplabel(char *label)
+{
+    uint8_t c;
+
+    while (1) {
+        c = *label++;
+        if (c >= 0xc0)
+            return ++label; /* pointer is two bytes */
+        if (c == 0)
+            return label;
+        label += c;
+    }
+}
+
+extern const uint8_t TimeoutTable[];
+extern uint16_t get_port(void);
+extern void free_port(uint16_t port);
+
+/*
+ * Actual resolver function
+ * Points to a null-terminated or :-terminated string in _name_
+ * and returns the ip addr in _ip_ if it exists and can be found.
+ * If _ip_ = 0 on exit, the lookup failed. _name_ will be updated
+ *
+ * XXX: probably need some caching here.
+ */
+__export uint32_t dns_resolv(const char *name)
+{
+    static char __lowmem DNSSendBuf[PKTBUF_SIZE];
+    static char __lowmem DNSRecvBuf[PKTBUF_SIZE];
+    char *p;
+    int err;
+    int dots;
+    int same;
+    int rd_len;
+    int ques, reps;    /* number of questions and replies */
+    uint8_t timeout;
+    const uint8_t *timeout_ptr = TimeoutTable;
+    uint32_t oldtime;
+    uint32_t srv;
+    uint32_t *srv_ptr;
+    struct dnshdr *hd1 = (struct dnshdr *)DNSSendBuf;
+    struct dnshdr *hd2 = (struct dnshdr *)DNSRecvBuf;
+    struct dnsquery *query;
+    struct dnsrr *rr;
+    static __lowmem struct s_PXENV_UDP_WRITE udp_write;
+    static __lowmem struct s_PXENV_UDP_READ  udp_read;
+    uint16_t local_port;
+    uint32_t result = 0;
+
+    /*
+     * Return failure on an empty input... this can happen during
+     * some types of URL parsing, and this is the easiest place to
+     * check for it.
+     */
+    if (!name || !*name)
+	return 0;
+
+    /* Make sure we have at least one valid DNS server */
+    if (!dns_server[0])
+	return 0;
+
+    /* Get a local port number */
+    local_port = get_port();
+
+    /* First, fill the DNS header struct */
+    hd1->id++;                      /* New query ID */
+    hd1->flags   = htons(0x0100);   /* Recursion requested */
+    hd1->qdcount = htons(1);        /* One question */
+    hd1->ancount = 0;               /* No answers */
+    hd1->nscount = 0;               /* No NS */
+    hd1->arcount = 0;               /* No AR */
+
+    p = DNSSendBuf + sizeof(struct dnshdr);
+    dots = dns_mangle(&p, name);   /* store the CNAME */
+
+    if (!dots) {
+        p--; /* Remove final null */
+        /* Uncompressed DNS label set so it ends in null */
+        p = stpcpy(p, LocalDomain);
+    }
+
+    /* Fill the DNS query packet */
+    query = (struct dnsquery *)p;
+    query->qtype  = htons(TYPE_A);
+    query->qclass = htons(CLASS_IN);
+    p += sizeof(struct dnsquery);
+
+    /* Now send it to name server */
+    timeout_ptr = TimeoutTable;
+    timeout = *timeout_ptr++;
+    srv_ptr = dns_server;
+    while (timeout) {
+	srv = *srv_ptr++;
+	if (!srv) {
+	    srv_ptr = dns_server;
+	    srv = *srv_ptr++;
+	}
+
+        udp_write.status      = 0;
+        udp_write.ip          = srv;
+        udp_write.gw          = gateway(srv);
+        udp_write.src_port    = local_port;
+        udp_write.dst_port    = DNS_PORT;
+        udp_write.buffer_size = p - DNSSendBuf;
+        udp_write.buffer      = FAR_PTR(DNSSendBuf);
+        err = pxe_call(PXENV_UDP_WRITE, &udp_write);
+        if (err || udp_write.status)
+            continue;
+
+        oldtime = jiffies();
+	do {
+	    if (jiffies() - oldtime >= timeout)
+		goto again;
+
+            udp_read.status      = 0;
+            udp_read.src_ip      = srv;
+            udp_read.dest_ip     = IPInfo.myip;
+            udp_read.s_port      = DNS_PORT;
+            udp_read.d_port      = local_port;
+            udp_read.buffer_size = PKTBUF_SIZE;
+            udp_read.buffer      = FAR_PTR(DNSRecvBuf);
+            err = pxe_call(PXENV_UDP_READ, &udp_read);
+	} while (err || udp_read.status || hd2->id != hd1->id);
+
+        if ((hd2->flags ^ 0x80) & htons(0xf80f))
+            goto badness;
+
+        ques = htons(hd2->qdcount);   /* Questions */
+        reps = htons(hd2->ancount);   /* Replies   */
+        p = DNSRecvBuf + sizeof(struct dnshdr);
+        while (ques--) {
+            p = dns_skiplabel(p); /* Skip name */
+            p += 4;               /* Skip question trailer */
+        }
+
+        /* Parse the replies */
+        while (reps--) {
+            same = dns_compare(DNSSendBuf + sizeof(struct dnshdr),
+			       p, DNSRecvBuf);
+            p = dns_skiplabel(p);
+            rr = (struct dnsrr *)p;
+            rd_len = ntohs(rr->rdlength);
+            if (same && ntohs(rr->class) == CLASS_IN) {
+		switch (ntohs(rr->type)) {
+		case TYPE_A:
+		    if (rd_len == 4) {
+			result = *(uint32_t *)rr->rdata;
+			goto done;
+		    }
+		    break;
+		case TYPE_CNAME:
+		    dns_copylabel(DNSSendBuf + sizeof(struct dnshdr),
+				  rr->rdata, DNSRecvBuf);
+		    /*
+		     * We should probably rescan the packet from the top
+		     * here, and technically we might have to send a whole
+		     * new request here...
+		     */
+		    break;
+		default:
+		    break;
+		}
+	    }
+
+            /* not the one we want, try next */
+            p += sizeof(struct dnsrr) + rd_len;
+        }
+
+    badness:
+        /*
+         *
+         ; We got back no data from this server.
+         ; Unfortunately, for a recursive, non-authoritative
+         ; query there is no such thing as an NXDOMAIN reply,
+         ; which technically means we can't draw any
+         ; conclusions.  However, in practice that means the
+         ; domain doesn't exist.  If this turns out to be a
+         ; problem, we may want to add code to go through all
+         ; the servers before giving up.
+
+         ; If the DNS server wasn't capable of recursion, and
+         ; isn't capable of giving us an authoritative reply
+         ; (i.e. neither AA or RA set), then at least try a
+         ; different setver...
+        */
+        if (hd2->flags == htons(0x480))
+            continue;
+
+        break; /* failed */
+
+    again:
+	continue;
+    }
+
+done:
+    free_port(local_port);	/* Return port number to the free pool */
+
+    return result;
+}
diff --git a/core/legacynet/idle.c b/core/legacynet/idle.c
new file mode 100644
index 00000000..e0892379
--- /dev/null
+++ b/core/legacynet/idle.c
@@ -0,0 +1,112 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2008 H. Peter Anvin - All Rights Reserved
+ *   Copyright 2009 Intel Corporation; author: H. Peter Anvin
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ *   Boston MA 02110-1301, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+#include <stdio.h>
+#include <string.h>
+#include <core.h>
+#include <fs.h>
+#include <minmax.h>
+#include <sys/cpu.h>
+#include "pxe.h"
+
+static int pxe_idle_poll(void)
+{
+    static __lowmem char junk_pkt[PKTBUF_SIZE];
+    static __lowmem t_PXENV_UDP_READ read_buf;
+
+    memset(&read_buf, 0, sizeof read_buf);
+
+    read_buf.src_ip  = 0;	 /* Any destination */
+    read_buf.dest_ip = IPInfo.myip;
+    read_buf.s_port  = 0;	 /* Any source port */
+    read_buf.d_port  = htons(9); /* Discard port (not used...) */
+    read_buf.buffer_size = sizeof junk_pkt;
+    read_buf.buffer  = FAR_PTR(junk_pkt);
+
+    pxe_call(PXENV_UDP_READ, &read_buf);
+
+    return 0;
+}
+
+static uint32_t pxe_detect_nic_type(void)
+{
+    static __lowmem t_PXENV_UNDI_GET_NIC_TYPE nic_type;
+
+    if (pxe_call(PXENV_UNDI_GET_NIC_TYPE, &nic_type))
+	return -1;		/* Unknown NIC */
+
+    if (nic_type.NicType != PCI_NIC && nic_type.NicType != CardBus_NIC)
+	return -1;		/* Not a PCI NIC */
+
+    /*
+     * Return VID:DID as a single number, with the VID in the high word
+     * -- this is opposite from the usual order, but it makes it easier to
+     * enforce that the table is sorted.
+     */
+    return (nic_type.info.pci.Vendor_ID << 16) + nic_type.info.pci.Dev_ID;
+}
+
+#define PCI_DEV(vid, did)	(((vid) << 16) + (did))
+
+/* This array should be sorted!! */
+static const uint32_t pxe_need_idle_drain[] =
+{
+    /*
+     * Older Broadcom NICs: they need receive calls on idle to avoid
+     * FIFO stalls.
+     */
+    PCI_DEV(0x14e4, 0x1659),	/* BCM5721 */
+    PCI_DEV(0x14e4, 0x165a),	/* BCM5722 */
+    PCI_DEV(0x14e4, 0x165b),	/* BCM5723 */
+    PCI_DEV(0x14e4, 0x1668),	/* BCM5714 */
+    PCI_DEV(0x14e4, 0x1669),	/* BCM5714S */
+    PCI_DEV(0x14e4, 0x166a),	/* BCM5780 */
+    PCI_DEV(0x14e4, 0x1673),	/* BCM5755M */
+    PCI_DEV(0x14e4, 0x1674),	/* BCM5756ME */
+    PCI_DEV(0x14e4, 0x1678),	/* BCM5715 */
+    PCI_DEV(0x14e4, 0x1679),	/* BCM5715S */
+    PCI_DEV(0x14e4, 0x167b),	/* BCM5755 */
+};
+
+void pxe_idle_init(void)
+{
+    uint32_t dev_id = pxe_detect_nic_type();
+    int l, h;
+    bool found;
+
+    l = 0;
+    h = sizeof pxe_need_idle_drain / sizeof pxe_need_idle_drain[0] - 1;
+
+    found = false;
+    while (h >= l) {
+	int x = (l+h) >> 1;
+	uint32_t id = pxe_need_idle_drain[x];
+
+	if (id == dev_id) {
+	    found = true;
+	    break;
+	} else if (id < dev_id) {
+	    l = x+1;
+	} else {
+	    h = x-1;
+	}
+    }
+
+    if (found)
+	idle_hook_func = pxe_idle_poll;
+}
+
+void pxe_idle_cleanup(void)
+{
+    idle_hook_func = NULL;
+}
diff --git a/core/fs/pxe/portnum.c b/core/legacynet/portnum.c
index 19af0cd0..e10af29e 100644
--- a/core/fs/pxe/portnum.c
+++ b/core/legacynet/portnum.c
@@ -1,5 +1,5 @@
 /* ----------------------------------------------------------------------- *
- *   
+ *
  *   Copyright 2010 Intel Corporation; author: H. Peter Anvin
  *
  *   This program is free software; you can redistribute it and/or modify
diff --git a/core/lwip/CHANGELOG b/core/lwip/CHANGELOG
new file mode 100644
index 00000000..6e27a66b
--- /dev/null
+++ b/core/lwip/CHANGELOG
@@ -0,0 +1,3050 @@
+HISTORY
+
+(CVS HEAD)
+
+  * [Enter new changes just after this line - do not remove this line]
+
+ ++ New features:
+
+
+ ++ Bugfixes:
+
+
+
+
+(STABLE-1.4.0)
+
+  ++ New features:
+
+  2011-03-27: Simon Goldschmidt
+  * tcp_impl.h, tcp_in.c, tcp_out.c: Removed 'dataptr' from 'struct tcp_seg' and
+    calculate it in tcp_zero_window_probe (the only place where it was used).
+
+  2010-11-21: Simon Goldschmidt
+  * dhcp.c/.h: Added a function to deallocate the struct dhcp from a netif
+    (fixes bug #31525).
+
+  2010-07-12: Simon Goldschmidt (patch by Stephane Lesage)
+  * ip.c, udp.c/.h, pbuf.h, sockets.c: task #10495: Added support for
+    IP_MULTICAST_LOOP at socket- and raw-API level.
+
+  2010-06-16: Simon Goldschmidt
+  * ip.c: Added an optional define (LWIP_IP_ACCEPT_UDP_PORT) that can allow
+    link-layer-addressed UDP traffic to be received while a netif is down (just
+    like DHCP during configuration)
+
+  2010-05-22: Simon Goldschmidt
+  * many many files: bug #27352: removed packing from ip_addr_t, the packed
+    version is now only used in protocol headers. Added global storage for
+    current src/dest IP address while in input functions.
+
+  2010-05-16: Simon Goldschmidt
+  * def.h: task #10391: Add preprocessor-macros for compile-time htonl
+    calculation (and use them throughout the stack where applicable)
+
+  2010-05-16: Simon Goldschmidt
+  * opt.h, memp_std.h, memp.c, ppp_oe.h/.c: PPPoE now uses its own MEMP pool
+    instead of the heap (moved struct pppoe_softc from ppp_oe.c to ppp_oe.h)
+
+  2010-05-16: Simon Goldschmidt
+  * opt.h, memp_std.h, dns.h/.c: DNS_LOCAL_HOSTLIST_IS_DYNAMIC uses its own
+    MEMP pool instead of the heap
+
+  2010-05-13: Simon Goldschmidt
+  * tcp.c, udp.c: task #6995: Implement SO_REUSEADDR (correctly), added
+    new option SO_REUSE_RXTOALL to pass received UDP broadcast/multicast
+    packets to more than one pcb.
+
+  2010-05-02: Simon Goldschmidt
+  * netbuf.h/.c, sockets.c, api_msg.c: use checksum-on-copy for sending
+    UDP data for LWIP_NETIF_TX_SINGLE_PBUF==1
+
+  2010-04-30: Simon Goldschmidt
+  * udp.h/.c, pbuf.h/.c: task #6849: added udp_send(_to/_if) functions that
+    take a precalculated checksum, added pbuf_fill_chksum() to copy data
+    into a pbuf and at the same time calculating the checksum for that data
+
+  2010-04-29: Simon Goldschmidt
+  * ip_addr.h, etharp.h/.c, autoip.c: Create overridable macros for copying
+    2-byte-aligned IP addresses and MAC addresses
+
+  2010-04-28: Patch by Bill Auerbach
+  * ip.c: Inline generating IP checksum to save a function call
+
+  2010-04-14: Simon Goldschmidt
+  * tcpip.h/.c, timers.c: Added an overridable define to get informed when the
+    tcpip_thread processes messages or timeouts to implement a watchdog.
+
+  2010-03-28: Simon Goldschmidt
+  * ip_frag.c: create a new (contiguous) PBUF_RAM for every outgoing
+    fragment if LWIP_NETIF_TX_SINGLE_PBUF==1
+
+  2010-03-27: Simon Goldschmidt
+  * etharp.c: Speedup TX by moving code from find_entry to etharp_output/
+    etharp_query to prevent unnecessary function calls (inspired by
+    patch #7135).
+
+  2010-03-20: Simon Goldschmidt
+  * opt.h, tcpip.c/.h: Added an option to disable tcpip_(un)timeout code
+    since the linker cannot do this automatically to save space.
+
+  2010-03-20: Simon Goldschmidt
+  * opt.h, etharp.c/.h: Added support for static ARP table entries
+
+  2010-03-14: Simon Goldschmidt
+  * tcp_impl.h, tcp_out.c, inet_chksum.h/.c: task #6849: Calculate checksum
+    when creating TCP segments, not when (re-)transmitting them.
+
+  2010-03-07: Simon Goldschmidt
+  * sockets.c: bug #28775 (select/event_callback: only check select_cb_list
+    on change) plus use SYS_LIGHTWEIGHT_PROT to protect the select code.
+    This should speed up receiving data on sockets as the select code in
+    event_callback is only executed when select is waiting.
+
+  2010-03-06: Simon Goldschmidt
+  * tcp_out.c: task #7013 (Create option to have all packets delivered to
+    netif->output in one piece): Always copy to try to create single pbufs
+    in tcp_write.
+
+  2010-03-06: Simon Goldschmidt
+  * api.h, api_lib.c, sockets.c: task #10167 (sockets: speed up TCP recv
+    by not allocating a netbuf): added function netconn_recv_tcp_pbuf()
+    for tcp netconns to receive pbufs, not netbufs; use that function
+    for tcp sockets.
+
+  2010-03-05: Jakob Ole Stoklundsen / Simon Goldschmidt
+  * opt.h, tcp.h, tcp_impl.h, tcp.c, tcp_in.c, tcp_out.c: task #7040:
+    Work on tcp_enqueue: Don't waste memory when chaining segments,
+    added option TCP_OVERSIZE to prevent creating many small pbufs when
+    calling tcp_write with many small blocks of data. Instead, pbufs are
+    allocated larger than needed and the space is used for later calls to
+    tcp_write.
+
+  2010-02-21: Simon Goldschmidt
+  * stats.c/.h: Added const char* name to mem- and memp-stats for easier
+    debugging.
+
+  2010-02-21: Simon Goldschmidt
+  * tcp.h (and usages), added tcp_impl.h: Splitted API and internal
+    implementation of tcp to make API usage cleare to application programmers
+
+  2010-02-14: Simon Goldschmidt/Stephane Lesage
+  * ip_addr.h: Improved some defines working on ip addresses, added faster
+    macro to copy addresses that cannot be NULL
+
+  2010-02-13: Simon Goldschmidt
+  * api.h, api_lib.c, api_msg.c, sockets.c: task #7865 (implement non-
+    blocking send operation)
+
+  2010-02-12: Simon Goldschmidt
+  * sockets.c/.h: Added a minimal version of posix fctl() to have a
+    standardised way to set O_NONBLOCK for nonblocking sockets.
+
+  2010-02-12: Simon Goldschmidt
+  * dhcp.c/.h, autoip.c/.h: task #10139 (Prefer statically allocated
+    memory): added autoip_set_struct() and dhcp_set_struct() to let autoip
+    and dhcp work with user-allocated structs instead of callin mem_malloc
+
+  2010-02-12: Simon Goldschmidt/Jeff Barber
+  * tcp.c/h: patch #6865 (SO_REUSEADDR for TCP): if pcb.so_options has
+    SOF_REUSEADDR set, allow binding to endpoint in TIME_WAIT
+
+  2010-02-12: Simon Goldschmidt
+  * sys layer: task #10139 (Prefer statically allocated memory): converted
+    mbox and semaphore functions to take pointers to sys_mbox_t/sys_sem_t;
+    converted sys_mbox_new/sys_sem_new to take pointers and return err_t;
+    task #7212: Add Mutex concept in sys_arch (define LWIP_COMPAT_MUTEX
+    to let sys.h use binary semaphores instead of mutexes - as before)
+
+  2010-02-09: Simon Goldschmidt (Simon Kallweit)
+  * timers.c/.h: Added function sys_restart_timeouts() from patch #7085
+    (Restart system timeout handling)
+
+  2010-02-09: Simon Goldschmidt
+  * netif.c/.h, removed loopif.c/.h: task #10153 (Integrate loopif into
+    netif.c) - loopif does not have to be created by the port any more,
+    just define LWIP_HAVE_LOOPIF to 1.
+
+  2010-02-08: Simon Goldschmidt
+  * inet.h, ip_addr.c/.h: Added reentrant versions of inet_ntoa/ipaddr_ntoa
+    inet_ntoa_r/ipaddr_ntoa_r
+
+  2010-02-08: Simon Goldschmidt
+  * netif.h: Added netif_s/get_igmp_mac_filter() macros
+
+  2010-02-05: Simon Goldschmidt
+  * netif.h: Added function-like macros to get/set the hostname on a netif
+
+  2010-02-04: Simon Goldschmidt
+  * nearly every file: Replaced struct ip_addr by typedef ip_addr_t to
+    make changing the actual implementation behind the typedef easier.
+
+  2010-02-01: Simon Goldschmidt
+  * opt.h, memp_std.h, dns.h, netdb.c, memp.c: Let netdb use a memp pool
+    for allocating memory when getaddrinfo() is called.
+
+  2010-01-31: Simon Goldschmidt
+  * dhcp.h, dhcp.c: Reworked the code that parses DHCP options: parse
+    them once instead of parsing for every option. This also removes
+    the need for mem_malloc from dhcp_recv and makes it possible to
+    correctly retrieve the BOOTP file.
+
+  2010-01-30: simon Goldschmidt
+  * sockets.c: Use SYS_LIGHTWEIGHT_PROT instead of a semaphore to protect
+    the sockets array.
+
+  2010-01-29: Simon Goldschmidt (patch by Laura Garrett)
+  * api.h, api_msg.c, sockets.c: Added except set support in select
+    (patch #6860)
+
+  2010-01-29: Simon Goldschmidt (patch by Laura Garrett)
+  * api.h, sockets.h, err.h, api_lib.c, api_msg.c, sockets.c, err.c:
+    Add non-blocking support for connect (partly from patch #6860),
+    plus many cleanups in socket & netconn API.
+
+  2010-01-27: Simon Goldschmidt
+  * opt.h, tcp.h, init.c, api_msg.c: Added TCP_SNDQUEUELOWAT corresponding
+    to TCP_SNDLOWAT and added tcp_sndqueuelen() - this fixes bug #28605
+
+  2010-01-26: Simon Goldschmidt
+  * snmp: Use memp pools for snmp instead of the heap; added 4 new pools.
+
+  2010-01-14: Simon Goldschmidt
+  * ppp.c/.h: Fixed bug #27856: PPP: Set netif link- and status-callback
+    by adding ppp_set_netif_statuscallback()/ppp_set_netif_linkcallback()
+
+  2010-01-13: Simon Goldschmidt
+  * mem.c: The heap now may be moved to user-defined memory by defining
+    LWIP_RAM_HEAP_POINTER as a void pointer to that memory's address
+    (patch #6966 and bug #26133)
+
+  2010-01-10: Simon Goldschmidt (Bill Auerbach)
+  * opt.h, memp.c: patch #6822 (Add option to place memory pools in
+    separate arrays)
+
+  2010-01-10: Simon Goldschmidt
+  * init.c, igmp.c: patch #6463 (IGMP - Adding Random Delay): added define
+    LWIP_RAND() for lwip-wide randomization (to be defined in cc.h)
+
+  2009-12-31: Simon Goldschmidt
+  * tcpip.c, init.c, memp.c, sys.c, memp_std.h, sys.h, tcpip.h
+    added timers.c/.h: Separated timer implementation from semaphore/mbox
+    implementation, moved timer implementation to timers.c/.h, timers are
+    now only called from tcpip_thread or by explicitly checking them.
+    (TASK#7235)
+
+  2009-12-27: Simon Goldschmidt
+  * opt.h, etharp.h/.c, init.c, tcpip.c: Added an additional option
+    LWIP_ETHERNET to support ethernet without ARP (necessary for pure PPPoE)
+
+
+  ++ Bugfixes:
+
+  2011-04-20: Simon Goldschmidt
+  * sys_arch.txt: sys_arch_timeouts() is not needed any more.
+
+  2011-04-13: Simon Goldschmidt
+  * tcp.c, udp.c: Fixed bug #33048 (Bad range for IP source port numbers) by
+    using ports in the IANA private/dynamic range (49152 through 65535).
+
+  2011-03-29: Simon Goldschmidt, patch by Emil Lhungdahl:
+  * etharp.h/.c: Fixed broken VLAN support.
+
+  2011-03-27: Simon Goldschmidt
+  * tcp.c: Fixed bug #32926 (TCP_RMV(&tcp_bound_pcbs) is called on unbound tcp
+    pcbs) by checking if the pcb was bound (local_port != 0).
+
+  2011-03-27: Simon Goldschmidt
+  * ppp.c: Fixed bug #32280 (ppp: a pbuf is freed twice)
+
+  2011-03-27: Simon Goldschmidt
+  * sockets.c: Fixed bug #32906: lwip_connect+lwip_send did not work for udp and
+    raw pcbs with LWIP_TCPIP_CORE_LOCKING==1.
+  
+  2011-03-27: Simon Goldschmidt
+  * tcp_out.c: Fixed bug #32820 (Outgoing TCP connections created before route
+    is present never times out) by starting retransmission timer before checking
+    route.
+
+  2011-03-22: Simon Goldschmidt
+  * ppp.c: Fixed bug #32648 (PPP code crashes when terminating a link) by only
+    calling sio_read_abort() if the file descriptor is valid.
+
+  2011-03-14: Simon Goldschmidt
+  * err.h/.c, sockets.c, api_msg.c: fixed bug #31748 (Calling non-blocking connect
+    more than once can render a socket useless) since it mainly involves changing
+    "FATAL" classification of error codes: ERR_USE and ERR_ISCONN just aren't fatal.
+
+  2011-03-13: Simon Goldschmidt
+  * sockets.c: fixed bug #32769 (ESHUTDOWN is linux-specific) by fixing
+    err_to_errno_table (ERR_CLSD: ENOTCONN instead of ESHUTDOWN), ERR_ISCONN:
+    use EALRADY instead of -1
+
+  2011-03-13: Simon Goldschmidt
+  * api_lib.c: netconn_accept: return ERR_ABRT instead of ERR_CLSD if the
+    connection has been aborted by err_tcp (since this is not a normal closing
+    procedure).
+
+  2011-03-13: Simon Goldschmidt
+  * tcp.c: tcp_bind: return ERR_VAL instead of ERR_ISCONN when trying to bind
+    with pcb->state != CLOSED
+
+  2011-02-17: Simon Goldschmidt
+  * rawapi.txt: Fixed bug #32561 tcp_poll argument definition out-of-order in
+    documentation
+
+  2011-02-17: Simon Goldschmidt
+  * many files: Added missing U/UL modifiers to fix 16-bit-arch portability.
+
+  2011-01-24: Simon Goldschmidt
+  * sockets.c: Fixed bug #31741: lwip_select seems to have threading problems
+
+  2010-12-02: Simon Goldschmidt
+  * err.h: Fixed ERR_IS_FATAL so that ERR_WOULDBLOCK is not fatal.
+
+  2010-11-23: Simon Goldschmidt
+  * api.h, api_lib.c, api_msg.c, sockets.c: netconn.recv_avail is only used for
+    LWIP_SO_RCVBUF and ioctl/FIONREAD.
+
+  2010-11-23: Simon Goldschmidt
+  * etharp.c: Fixed bug #31720: ARP-queueing: RFC 1122 recommends to queue at
+    least 1 packet -> ARP_QUEUEING==0 now queues the most recent packet.
+
+  2010-11-23: Simon Goldschmidt
+  * tcp_in.c: Fixed bug #30577: tcp_input: don't discard ACK-only packets after
+    refusing 'refused_data' again.
+  
+  2010-11-22: Simon Goldschmidt
+  * sockets.c: Fixed bug #31590: getsockopt(... SO_ERROR ...) gives EINPROGRESS
+    after a successful nonblocking connection.
+
+  2010-11-22: Simon Goldschmidt
+  * etharp.c: Fixed bug #31722: IP packets sent with an AutoIP source addr
+    must be sent link-local
+
+  2010-11-22: Simon Goldschmidt
+  * timers.c: patch #7329: tcp_timer_needed prototype was ifdef'ed out for
+    LWIP_TIMERS==0
+
+  2010-11-20: Simon Goldschmidt
+  * sockets.c: Fixed bug #31170: lwip_setsockopt() does not set socket number
+
+  2010-11-20: Simon Goldschmidt
+  * sockets.h: Fixed bug #31304: Changed SHUT_RD, SHUT_WR and SHUT_RDWR to
+    resemble other stacks.
+
+  2010-11-20: Simon Goldschmidt
+  * dns.c: Fixed bug #31535: TCP_SND_QUEUELEN must be at least 2 or else
+    no-copy TCP writes will never succeed.
+
+  2010-11-20: Simon Goldschmidt
+  * dns.c: Fixed bug #31701: Error return value from dns_gethostbyname() does
+    not match documentation: return ERR_ARG instead of ERR_VAL if not
+    initialized or wrong argument.
+
+  2010-10-20: Simon Goldschmidt
+  * sockets.h: Fixed bug #31385: sizeof(struct sockaddr) is 30 but should be 16
+
+  2010-10-05: Simon Goldschmidt
+  * dhcp.c: Once again fixed #30038: DHCP/AutoIP cooperation failed when
+    replugging the network cable after an AutoIP address was assigned.
+
+  2010-08-10: Simon Goldschmidt
+  * tcp.c: Fixed bug #30728: tcp_new_port() did not check listen pcbs
+
+  2010-08-03: Simon Goldschmidt
+  * udp.c, raw.c: Don't chain empty pbufs when sending them (fixes bug #30625)
+
+  2010-08-01: Simon Goldschmidt (patch by Greg Renda)
+  * ppp.c: Applied patch #7264 (PPP protocols are rejected incorrectly on big
+    endian architectures)
+  
+  2010-07-28: Simon Goldschmidt
+  * api_lib.c, api_msg.c, sockets.c, mib2.c: Fixed compilation with TCP or UDP
+    disabled.
+  
+  2010-07-27: Simon Goldschmidt
+  * tcp.c: Fixed bug #30565 (tcp_connect() check bound list): that check did no
+    harm but never did anything
+  
+  2010-07-21: Simon Goldschmidt
+  * ip.c: Fixed invalid fix for bug #30402 (CHECKSUM_GEN_IP_INLINE does not
+    add IP options)
+
+  2010-07-16: Kieran Mansley
+  * msg_in.c: Fixed SNMP ASN constant defines to not use ! operator 
+
+  2010-07-10: Simon Goldschmidt
+  * ip.c: Fixed bug #30402: CHECKSUM_GEN_IP_INLINE does not add IP options
+
+  2010-06-30: Simon Goldschmidt
+  * api_msg.c: fixed bug #30300 (shutdown parameter was not initialized in
+    netconn_delete)
+
+  2010-06-28: Kieran Mansley
+  * timers.c remove unportable printing of C function pointers
+
+  2010-06-24: Simon Goldschmidt
+  * init.c, timers.c/.h, opt.h, memp_std.h: From patch #7221: added flag
+    NO_SYS_NO_TIMERS to drop timer support for NO_SYS==1 for easier upgrading
+
+  2010-06-24: Simon Goldschmidt
+  * api(_lib).c/.h, api_msg.c/.h, sockets.c/.h: Fixed bug #10088: Correctly
+    implemented shutdown at socket level.
+
+  2010-06-21: Simon Goldschmidt
+  * pbuf.c/.h, ip_frag.c/.h, opt.h, memp_std.h: Fixed bug #29361 (ip_frag has
+    problems with zero-copy DMA MACs) by adding custom pbufs and implementing
+    custom pbufs that reference other (original) pbufs. Additionally set
+    IP_FRAG_USES_STATIC_BUF=0 as default to be on the safe side.
+
+  2010-06-15: Simon Goldschmidt
+  * dhcp.c: Fixed bug #29970: DHCP endian issue parsing option responses
+
+  2010-06-14: Simon Goldschmidt
+  * autoip.c: Fixed bug #30039: AutoIP does not reuse previous addresses
+
+  2010-06-12: Simon Goldschmidt
+  * dhcp.c: Fixed bug #30038: dhcp_network_changed doesn't reset AUTOIP coop
+    state
+
+  2010-05-17: Simon Goldschmidt
+  * netdb.c: Correctly NULL-terminate h_addr_list
+
+  2010-05-16: Simon Goldschmidt
+  * def.h/.c: changed the semantics of LWIP_PREFIX_BYTEORDER_FUNCS to prevent
+    "symbol already defined" i.e. when linking to winsock
+
+  2010-05-05: Simon Goldschmidt
+  * def.h, timers.c: Fixed bug #29769 (sys_check_timeouts: sys_now() may
+    overflow)
+
+  2010-04-21: Simon Goldschmidt
+  * api_msg.c: Fixed bug #29617 (sometime cause stall on delete listening
+    connection)
+
+  2010-03-28: Luca Ceresoli
+  * ip_addr.c/.h: patch #7143: Add a few missing const qualifiers
+
+  2010-03-27: Luca Ceresoli
+  * mib2.c: patch #7130: remove meaningless const qualifiers
+
+  2010-03-26: Simon Goldschmidt
+  * tcp_out.c: Make LWIP_NETIF_TX_SINGLE_PBUF work for TCP, too
+
+  2010-03-26: Simon Goldschmidt
+  * various files: Fixed compiling with different options disabled (TCP/UDP),
+    triggered by bug #29345; don't allocate acceptmbox if LWIP_TCP is disabled
+
+  2010-03-25: Simon Goldschmidt
+  * sockets.c: Fixed bug #29332: lwip_select() processes readset incorrectly
+
+  2010-03-25: Simon Goldschmidt
+  * tcp_in.c, test_tcp_oos.c: Fixed bug #29080: Correctly handle remote side
+    overrunning our rcv_wnd in ooseq case.
+
+  2010-03-22: Simon Goldschmidt
+  * tcp.c: tcp_listen() did not copy the pcb's prio.
+
+  2010-03-19: Simon Goldschmidt
+  * snmp_msg.c: Fixed bug #29256: SNMP Trap address was not correctly set
+
+  2010-03-14: Simon Goldschmidt
+  * opt.h, etharp.h: Fixed bug #29148 (Incorrect PBUF_POOL_BUFSIZE for ports
+    where ETH_PAD_SIZE > 0) by moving definition of ETH_PAD_SIZE to opt.h
+    and basing PBUF_LINK_HLEN on it.
+
+  2010-03-08: Simon Goldschmidt
+  * netif.c, ipv4/ip.c: task #10241 (AutoIP: don't break existing connections
+    when assiging routable address): when checking incoming packets and
+    aborting existing connection on address change, filter out link-local
+    addresses.
+
+  2010-03-06: Simon Goldschmidt
+  * sockets.c: Fixed LWIP_NETIF_TX_SINGLE_PBUF for LWIP_TCPIP_CORE_LOCKING
+
+  2010-03-06: Simon Goldschmidt
+  * ipv4/ip.c: Don't try to forward link-local addresses
+
+  2010-03-06: Simon Goldschmidt
+  * etharp.c: Fixed bug #29087: etharp: don't send packets for LinkLocal-
+    addresses to gw
+
+  2010-03-05: Simon Goldschmidt
+  * dhcp.c: Fixed bug #29072: Correctly set ciaddr based on message-type
+    and state.
+
+  2010-03-05: Simon Goldschmidt
+  * api_msg.c: Correctly set TCP_WRITE_FLAG_MORE when netconn_write is split
+    into multiple calls to tcp_write.    
+
+  2010-02-21: Simon Goldschmidt
+  * opt.h, mem.h, dns.c: task #10140: Remove DNS_USES_STATIC_BUF (keep
+    the implementation of DNS_USES_STATIC_BUF==1)
+
+  2010-02-20: Simon Goldschmidt
+  * tcp.h, tcp.c, tcp_in.c, tcp_out.c: Task #10088: Correctly implement
+    close() vs. shutdown(). Now the application does not get any more
+    recv callbacks after calling tcp_close(). Added tcp_shutdown().
+
+  2010-02-19: Simon Goldschmidt
+  * mem.c/.h, pbuf.c: Renamed mem_realloc() to mem_trim() to prevent
+    confusion with realloc()
+
+  2010-02-15: Simon Goldschmidt/Stephane Lesage
+  * netif.c/.h: Link status does not depend on LWIP_NETIF_LINK_CALLBACK
+    (fixes bug #28899)
+
+  2010-02-14: Simon Goldschmidt
+  * netif.c: Fixed bug #28877 (Duplicate ARP gratuitous packet with
+    LWIP_NETIF_LINK_CALLBACK set on) by only sending if both link- and
+    admin-status of a netif are up
+
+  2010-02-14: Simon Goldschmidt
+  * opt.h: Disable ETHARP_TRUST_IP_MAC by default since it slows down packet
+    reception and is not really necessary
+
+  2010-02-14: Simon Goldschmidt
+  * etharp.c/.h: Fixed ARP input processing: only add a new entry if a
+    request was directed as us (RFC 826, Packet Reception), otherwise
+    only update existing entries; internalized some functions
+
+  2010-02-14: Simon Goldschmidt
+  * netif.h, etharp.c, tcpip.c: Fixed bug #28183 (ARP and TCP/IP cannot be
+    disabled on netif used for PPPoE) by adding a new netif flag
+    (NETIF_FLAG_ETHERNET) that tells the stack the device is an ethernet
+    device but prevents usage of ARP (so that ethernet_input can be used
+    for PPPoE).
+
+  2010-02-12: Simon Goldschmidt
+  * netif.c: netif_set_link_up/down: only do something if the link state
+    actually changes
+
+  2010-02-12: Simon Goldschmidt/Stephane Lesage
+  * api_msg.c: Fixed bug #28865 (Cannot close socket/netconn in non-blocking
+    connect)
+
+  2010-02-12: Simon Goldschmidt
+  * mem.h: Fixed bug #28866 (mem_realloc function defined in mem.h)
+
+  2010-02-09: Simon Goldschmidt
+  * api_lib.c, api_msg.c, sockets.c, api.h, api_msg.h: Fixed bug #22110
+   (recv() makes receive window update for data that wasn't received by
+    application)
+
+  2010-02-09: Simon Goldschmidt/Stephane Lesage
+  * sockets.c: Fixed bug #28853 (lwip_recvfrom() returns 0 on receive time-out
+    or any netconn_recv() error)
+
+  2010-02-09: Simon Goldschmidt
+  * ppp.c: task #10154 (PPP: Update snmp in/out counters for tx/rx packets)
+
+  2010-02-09: Simon Goldschmidt
+  * netif.c: For loopback packets, adjust the stats- and snmp-counters
+    for the loopback netif.
+
+  2010-02-08: Simon Goldschmidt
+  * igmp.c/.h, ip.h: Moved most defines from igmp.h to igmp.c for clarity
+    since they are not used anywhere else.
+
+  2010-02-08: Simon Goldschmidt (Stéphane Lesage)
+  * igmp.c, igmp.h, stats.c, stats.h: Improved IGMP stats
+    (patch from bug #28798)
+
+  2010-02-08: Simon Goldschmidt (Stéphane Lesage)
+  * igmp.c: Fixed bug #28798 (Error in "Max Response Time" processing) and
+    another bug when LWIP_RAND() returns zero.
+
+  2010-02-04: Simon Goldschmidt
+  * nearly every file: Use macros defined in ip_addr.h (some of them new)
+    to work with IP addresses (preparation for bug #27352 - Change ip_addr
+    from struct to typedef (u32_t) - and better code).
+
+  2010-01-31: Simon Goldschmidt
+  * netif.c: Don't call the link-callback from netif_set_up/down() since
+    this invalidly retriggers DHCP.
+
+  2010-01-29: Simon Goldschmidt
+  * ip_addr.h, inet.h, def.h, inet.c, def.c, more: Cleanly separate the
+    portability file inet.h and its contents from the stack: moved htonX-
+    functions to def.h (and the new def.c - they are not ipv4 dependent),
+    let inet.h depend on ip_addr.h and not the other way round.
+    This fixes bug #28732.
+
+  2010-01-28: Kieran Mansley
+  * tcp.c: Ensure ssthresh >= 2*MSS
+
+  2010-01-27: Simon Goldschmidt
+  * tcp.h, tcp.c, tcp_in.c: Fixed bug #27871: Calling tcp_abort() in recv
+    callback can lead to accessing unallocated memory. As a consequence,
+    ERR_ABRT means the application has called tcp_abort()!
+
+  2010-01-25: Simon Goldschmidt
+  * snmp_structs.h, msg_in.c: Partly fixed bug #22070 (MIB_OBJECT_WRITE_ONLY
+    not implemented in SNMP): write-only or not-accessible are still
+    returned by getnext (though not by get)
+
+  2010-01-24: Simon Goldschmidt
+  * snmp: Renamed the private mib node from 'private' to 'mib_private' to
+    not use reserved C/C++ keywords
+
+  2010-01-23: Simon Goldschmidt
+  * sockets.c: Fixed bug #28716: select() returns 0 after waiting for less
+    than 1 ms
+
+  2010-01-21: Simon Goldschmidt
+  * tcp.c, api_msg.c: Fixed bug #28651 (tcp_connect: no callbacks called
+    if tcp_enqueue fails) both in raw- and netconn-API
+
+  2010-01-19: Simon Goldschmidt
+  * api_msg.c: Fixed bug #27316: netconn: Possible deadlock in err_tcp
+
+  2010-01-18: Iordan Neshev/Simon Goldschmidt
+  * src/netif/ppp: reorganised PPP sourcecode to 2.3.11 including some
+    bugfix backports from 2.4.x.
+
+  2010-01-18: Simon Goldschmidt
+  * mem.c: Fixed bug #28679: mem_realloc calculates mem_stats wrong
+
+  2010-01-17: Simon Goldschmidt
+  * api_lib.c, api_msg.c, (api_msg.h, api.h, sockets.c, tcpip.c):
+    task #10102: "netconn: clean up conn->err threading issues" by adding
+    error return value to struct api_msg_msg
+
+  2010-01-17: Simon Goldschmidt
+  * api.h, api_lib.c, sockets.c: Changed netconn_recv() and netconn_accept()
+    to return err_t (bugs #27709 and #28087)
+
+  2010-01-14: Simon Goldschmidt
+  * ...: Use typedef for function prototypes throughout the stack.
+
+  2010-01-13: Simon Goldschmidt
+  * api_msg.h/.c, api_lib.c: Fixed bug #26672 (close connection when receive
+    window = 0) by correctly draining recvmbox/acceptmbox
+
+  2010-01-11: Simon Goldschmidt
+  * pap.c: Fixed bug #13315 (PPP PAP authentication can result in
+    erroneous callbacks) by copying the code from recent pppd
+
+  2010-01-10: Simon Goldschmidt
+  * raw.c: Fixed bug #28506 (raw_bind should filter received packets)
+
+  2010-01-10: Simon Goldschmidt
+  * tcp.h/.c: bug #28127 (remove call to tcp_output() from tcp_ack(_now)())
+
+  2010-01-08: Simon Goldschmidt
+  * sockets.c: Fixed bug #28519 (lwip_recvfrom bug with len > 65535)
+
+  2010-01-08: Simon Goldschmidt
+  * dns.c: Copy hostname for DNS_LOCAL_HOSTLIST_IS_DYNAMIC==1 since string
+    passed to dns_local_addhost() might be volatile
+
+  2010-01-07: Simon Goldschmidt
+  * timers.c, tcp.h: Call tcp_timer_needed() with NO_SYS==1, too
+
+  2010-01-06: Simon Goldschmidt
+  * netdb.h: Fixed bug #28496: missing include guards in netdb.h
+
+  2009-12-31: Simon Goldschmidt
+  * many ppp files: Reorganised PPP source code from ucip structure to pppd
+    structure to easily compare our code against the pppd code (around v2.3.1)
+
+  2009-12-27: Simon Goldschmidt
+  * tcp_in.c: Another fix for bug #28241 (ooseq processing) and adapted
+    unit test
+
+
+(STABLE-1.3.2)
+
+  ++ New features:
+
+  2009-10-27 Simon Goldschmidt/Stephan Lesage
+  * netifapi.c/.h: Added netifapi_netif_set_addr()
+
+  2009-10-07 Simon Goldschmidt/Fabian Koch
+  * api_msg.c, netbuf.c/.h, opt.h: patch #6888: Patch for UDP Netbufs to
+    support dest-addr and dest-port (optional: LWIP_NETBUF_RECVINFO)
+
+  2009-08-26 Simon Goldschmidt/Simon Kallweit
+  * slipif.c/.h: bug #26397: SLIP polling support
+
+  2009-08-25 Simon Goldschmidt
+  * opt.h, etharp.h/.c: task #9033: Support IEEE 802.1q tagged frame (VLAN),
+    New configuration options ETHARP_SUPPORT_VLAN and ETHARP_VLAN_CHECK.
+
+  2009-08-25 Simon Goldschmidt
+  * ip_addr.h, netdb.c: patch #6900: added define ip_ntoa(struct ip_addr*)
+
+  2009-08-24 Jakob Stoklund Olesen
+  * autoip.c, dhcp.c, netif.c: patch #6725: Teach AutoIP and DHCP to respond
+    to netif_set_link_up().
+
+  2009-08-23 Simon Goldschmidt
+  * tcp.h/.c: Added function tcp_debug_state_str() to convert a tcp state
+    to a human-readable string.
+
+  ++ Bugfixes:
+
+  2009-12-24: Kieran Mansley
+  * tcp_in.c Apply patches from Oleg Tyshev to improve OOS processing
+    (BUG#28241)
+
+  2009-12-06: Simon Goldschmidt
+  * ppp.h/.c: Fixed bug #27079 (Yet another leak in PPP): outpacket_buf can
+    be statically allocated (like in ucip)
+
+  2009-12-04: Simon Goldschmidt (patch by Ioardan Neshev)
+  * pap.c: patch #6969: PPP: missing PAP authentication UNTIMEOUT
+
+  2009-12-03: Simon Goldschmidt
+  * tcp.h, tcp_in.c, tcp_out.c: Fixed bug #28106: dup ack for fast retransmit
+    could have non-zero length
+
+  2009-12-02: Simon Goldschmidt
+  * tcp_in.c: Fixed bug #27904: TCP sends too many ACKs: delay resetting
+    tcp_input_pcb until after calling the pcb's callbacks
+
+  2009-11-29: Simon Goldschmidt
+  * tcp_in.c: Fixed bug #28054: Two segments with FIN flag on the out-of-
+    sequence queue, also fixed PBUF_POOL leak in the out-of-sequence code
+
+  2009-11-29: Simon Goldschmidt
+  * pbuf.c: Fixed bug #28064: pbuf_alloc(PBUF_POOL) is not thread-safe by
+    queueing a call into tcpip_thread to free ooseq-bufs if the pool is empty
+
+  2009-11-26: Simon Goldschmidt
+  * tcp.h: Fixed bug #28098: Nagle can prevent fast retransmit from sending
+    segment
+
+  2009-11-26: Simon Goldschmidt
+  * tcp.h, sockets.c: Fixed bug #28099: API required to disable Nagle
+    algorithm at PCB level
+
+  2009-11-22: Simon Goldschmidt
+  * tcp_out.c: Fixed bug #27905: FIN isn't combined with data on unsent
+
+  2009-11-22: Simon Goldschmidt (suggested by Bill Auerbach)
+  * tcp.c: tcp_alloc: prevent increasing stats.err for MEMP_TCP_PCB when
+    reusing time-wait pcb
+
+  2009-11-20: Simon Goldschmidt (patch by Albert Bartel)
+  * sockets.c: Fixed bug #28062: Data received directly after accepting
+    does not wake up select
+
+  2009-11-11: Simon Goldschmidt
+  * netdb.h: Fixed bug #27994: incorrect define for freeaddrinfo(addrinfo)
+
+  2009-10-30: Simon Goldschmidt
+  * opt.h: Increased default value for TCP_MSS to 536, updated default
+    value for TCP_WND to 4*TCP_MSS to keep delayed ACK working.
+
+  2009-10-28: Kieran Mansley
+  * tcp_in.c, tcp_out.c, tcp.h: re-work the fast retransmission code
+    to follow algorithm from TCP/IP Illustrated
+
+  2009-10-27: Kieran Mansley
+  * tcp_in.c: fix BUG#27445: grow cwnd with every duplicate ACK
+
+  2009-10-25: Simon Goldschmidt
+  * tcp.h: bug-fix in the TCP_EVENT_RECV macro (has to call tcp_recved if
+    pcb->recv is NULL to keep rcv_wnd correct)
+
+  2009-10-25: Simon Goldschmidt
+  * tcp_in.c: Fixed bug #26251: RST process in TIME_WAIT TCP state
+
+  2009-10-23: Simon Goldschmidt (David Empson)
+  * tcp.c: Fixed bug #27783: Silly window avoidance for small window sizes
+
+  2009-10-21: Simon Goldschmidt
+  * tcp_in.c: Fixed bug #27215: TCP sent() callback gives leading and
+    trailing 1 byte len (SYN/FIN)
+
+  2009-10-21: Simon Goldschmidt
+  * tcp_out.c: Fixed bug #27315: zero window probe and FIN
+
+  2009-10-19: Simon Goldschmidt
+  * dhcp.c/.h: Minor code simplification (don't store received pbuf, change
+    conditional code to assert where applicable), check pbuf length before
+    testing for valid reply
+
+  2009-10-19: Simon Goldschmidt
+  * dhcp.c: Removed most calls to udp_connect since they aren't necessary
+    when using udp_sendto_if() - always stay connected to IP_ADDR_ANY.
+
+  2009-10-16: Simon Goldschmidt
+  * ip.c: Fixed bug #27390: Source IP check in ip_input() causes it to drop
+    valid DHCP packets -> allow 0.0.0.0 as source address when LWIP_DHCP is
+    enabled
+
+  2009-10-15: Simon Goldschmidt (Oleg Tyshev)
+  * tcp_in.c: Fixed bug #27329: dupacks by unidirectional data transmit
+
+  2009-10-15: Simon Goldschmidt
+  * api_lib.c: Fixed bug #27709: conn->err race condition on netconn_recv()
+    timeout
+
+  2009-10-15: Simon Goldschmidt
+  * autoip.c: Fixed bug #27704: autoip starts with wrong address
+    LWIP_AUTOIP_CREATE_SEED_ADDR() returned address in host byte order instead
+    of network byte order
+
+  2009-10-11 Simon Goldschmidt (Jörg Kesten)
+  * tcp_out.c: Fixed bug #27504: tcp_enqueue wrongly concatenates segments
+    which are not consecutive when retransmitting unacked segments
+
+  2009-10-09 Simon Goldschmidt
+  * opt.h: Fixed default values of some stats to only be enabled if used
+    Fixes bug #27338: sys_stats is defined when NO_SYS = 1
+
+  2009-08-30 Simon Goldschmidt
+  * ip.c: Fixed bug bug #27345: "ip_frag() does not use the LWIP_NETIF_LOOPBACK
+    function" by checking for loopback before calling ip_frag
+
+  2009-08-25 Simon Goldschmidt
+  * dhcp.c: fixed invalid dependency to etharp_query if DHCP_DOES_ARP_CHECK==0
+
+  2009-08-23 Simon Goldschmidt
+  * ppp.c: bug #27078: Possible memory leak in pppInit()
+
+  2009-08-23 Simon Goldschmidt
+  * netdb.c, dns.c: bug #26657: DNS, if host name is "localhost", result
+    is error.
+
+  2009-08-23 Simon Goldschmidt
+  * opt.h, init.c: bug #26649: TCP fails when TCP_MSS > TCP_SND_BUF
+    Fixed wrong parenthesis, added check in init.c
+
+  2009-08-23 Simon Goldschmidt
+  * ppp.c: bug #27266: wait-state debug message in pppMain occurs every ms
+
+  2009-08-23 Simon Goldschmidt
+  * many ppp files: bug #27267: Added include to string.h where needed
+
+  2009-08-23 Simon Goldschmidt
+  * tcp.h: patch #6843: tcp.h macro optimization patch (for little endian)
+
+
+(STABLE-1.3.1)
+
+  ++ New features:
+
+  2009-05-10 Simon Goldschmidt
+  * opt.h, sockets.c, pbuf.c, netbuf.h, pbuf.h: task #7013: Added option
+    LWIP_NETIF_TX_SINGLE_PBUF to try to create transmit packets from only
+    one pbuf to help MACs that don't support scatter-gather DMA.
+
+  2009-05-09 Simon Goldschmidt
+  * icmp.h, icmp.c: Shrinked ICMP code, added option to NOT check icoming
+    ECHO pbuf for size (just use it): LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
+
+  2009-05-05 Simon Goldschmidt, Jakob Stoklund Olesen
+  * ip.h, ip.c: Added ip_current_netif() & ip_current_header() to receive
+    extended info about the currently received packet.
+
+  2009-04-27 Simon Goldschmidt
+  * sys.h: Made SYS_LIGHTWEIGHT_PROT and sys_now() work with NO_SYS=1
+
+  2009-04-25 Simon Goldschmidt
+  * mem.c, opt.h: Added option MEM_USE_POOLS_TRY_BIGGER_POOL to try the next
+    bigger malloc pool if one is empty (only usable with MEM_USE_POOLS).
+
+  2009-04-21 Simon Goldschmidt
+  * dns.c, init.c, dns.h, opt.h: task #7507, patch #6786: DNS supports static
+    hosts table. New configuration options DNS_LOCAL_HOSTLIST and
+    DNS_LOCAL_HOSTLIST_IS_DYNAMIC. Also, DNS_LOOKUP_LOCAL_EXTERN() can be defined
+    as an external function for lookup.
+
+  2009-04-15 Simon Goldschmidt
+  * dhcp.c: patch #6763: Global DHCP XID can be redefined to something more unique
+
+  2009-03-31 Kieran Mansley
+  * tcp.c, tcp_out.c, tcp_in.c, sys.h, tcp.h, opts.h: add support for
+    TCP timestamp options, off by default.  Rework tcp_enqueue() to
+    take option flags rather than specified option data
+
+  2009-02-18 Simon Goldschmidt
+  * cc.h: Added printf formatter for size_t: SZT_F
+
+  2009-02-16 Simon Goldschmidt (patch by Rishi Khan)
+  * icmp.c, opt.h: patch #6539: (configurable) response to broadcast- and multicast
+    pings
+
+  2009-02-12 Simon Goldschmidt
+  * init.h: Added LWIP_VERSION to get the current version of the stack
+
+  2009-02-11 Simon Goldschmidt (suggested by Gottfried Spitaler)
+  * opt.h, memp.h/.c: added MEMP_MEM_MALLOC to use mem_malloc/mem_free instead
+    of the pool allocator (can save code size with MEM_LIBC_MALLOC if libc-malloc
+    is otherwise used)
+
+  2009-01-28 Jonathan Larmour (suggested by Bill Bauerbach)
+  * ipv4/inet_chksum.c, ipv4/lwip/inet_chksum.h: inet_chksum_pseudo_partial()
+  is only used by UDPLITE at present, so conditionalise it.
+
+  2008-12-03 Simon Goldschmidt (base on patch from Luca Ceresoli)
+  * autoip.c: checked in (slightly modified) patch #6683: Customizable AUTOIP
+    "seed" address. This should reduce AUTOIP conflicts if
+    LWIP_AUTOIP_CREATE_SEED_ADDR is overridden.
+
+  2008-10-02 Jonathan Larmour and Rishi Khan
+  * sockets.c (lwip_accept): Return EWOULDBLOCK if would block on non-blocking
+    socket.
+
+  2008-06-30 Simon Goldschmidt
+  * mem.c, opt.h, stats.h: fixed bug #21433: Calling mem_free/pbuf_free from
+    interrupt context isn't safe: LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT allows
+    mem_free to run between mem_malloc iterations. Added illegal counter for
+    mem stats.
+
+  2008-06-27 Simon Goldschmidt
+  * stats.h/.c, some other files: patch #6483: stats module improvement:
+    Added defines to display each module's statistic individually, added stats
+    defines for MEM, MEMP and SYS modules, removed (unused) rexmit counter.
+
+  2008-06-17 Simon Goldschmidt
+  * err.h: patch #6459: Made err_t overridable to use a more efficient type
+    (define LWIP_ERR_T in cc.h)
+
+  2008-06-17 Simon Goldschmidt
+  * slipif.c: patch #6480: Added a configuration option for slipif for symmetry
+    to loopif
+
+  2008-06-17 Simon Goldschmidt (patch by Luca Ceresoli)
+  * netif.c, loopif.c, ip.c, netif.h, loopif.h, opt.h: Checked in slightly
+    modified version of patch # 6370: Moved loopif code to netif.c so that
+    loopback traffic is supported on all netifs (all local IPs).
+    Added option to limit loopback packets for each netifs.
+
+
+  ++ Bugfixes:
+  2009-08-12 Kieran Mansley
+  * tcp_in.c, tcp.c: Fix bug #27209: handle trimming of segments when
+    out of window or out of order properly
+
+  2009-08-12 Kieran Mansley
+  * tcp_in.c: Fix bug #27199: use snd_wl2 instead of snd_wl1
+
+  2009-07-28 Simon Goldschmidt
+  * mem.h: Fixed bug #27105: "realloc() cannot replace mem_realloc()"s
+
+  2009-07-27 Kieran Mansley
+  * api.h api_msg.h netdb.h sockets.h: add missing #include directives
+
+  2009-07-09 Kieran Mansley
+  * api_msg.c, sockets.c, api.h: BUG23240 use signed counters for
+    recv_avail and don't increment counters until message successfully
+    sent to mbox
+
+  2009-06-25 Kieran Mansley
+  * api_msg.c api.h: BUG26722: initialise netconn write variables 
+    in netconn_alloc
+
+  2009-06-25 Kieran Mansley
+  * tcp.h: BUG26879: set ret value in TCP_EVENT macros when function is not set
+
+  2009-06-25 Kieran Mansley
+  * tcp.c, tcp_in.c, tcp_out.c, tcp.h: BUG26301 and BUG26267: correct
+    simultaneous close behaviour, and make snd_nxt have the same meaning 
+    as in the RFCs.
+
+  2009-05-12 Simon Goldschmidt
+  * etharp.h, etharp.c, netif.c: fixed bug #26507: "Gratuitous ARP depends on
+    arp_table / uses etharp_query" by adding etharp_gratuitous()
+
+  2009-05-12 Simon Goldschmidt
+  * ip.h, ip.c, igmp.c: bug #26487: Added ip_output_if_opt that can add IP options
+    to the IP header (used by igmp_ip_output_if)
+
+  2009-05-06 Simon Goldschmidt
+  * inet_chksum.c: On little endian architectures, use LWIP_PLATFORM_HTONS (if
+    defined) for SWAP_BYTES_IN_WORD to speed up checksumming.
+
+  2009-05-05 Simon Goldschmidt
+  * sockets.c: bug #26405: Prematurely released semaphore causes lwip_select()
+    to crash
+
+  2009-05-04 Simon Goldschmidt
+  * init.c: snmp was not initialized in lwip_init()
+
+  2009-05-04 Frédéric Bernon
+  * dhcp.c, netbios.c: Changes if IP_SOF_BROADCAST is enabled.
+
+  2009-05-03 Simon Goldschmidt
+  * tcp.h: bug #26349: Nagle algorithm doesn't send although segment is full
+    (and unsent->next == NULL)
+
+  2009-05-02 Simon Goldschmidt
+  * tcpip.h, tcpip.c: fixed tcpip_untimeout (does not need the time, broken after
+    1.3.0 in CVS only) - fixes compilation of ppp_oe.c
+
+  2009-05-02 Simon Goldschmidt
+  * msg_in.c: fixed bug #25636: SNMPSET value is ignored for integer fields
+
+  2009-05-01 Simon Goldschmidt
+  * pap.c: bug #21680: PPP upap_rauthnak() drops legal NAK packets
+
+  2009-05-01 Simon Goldschmidt
+  * ppp.c: bug #24228: Memory corruption with PPP and DHCP
+
+  2009-04-29 Frédéric Bernon
+  * raw.c, udp.c, init.c, opt.h, ip.h, sockets.h: bug #26309: Implement the
+    SO(F)_BROADCAST filter for all API layers. Avoid the unindented reception
+    of broadcast packets even when this option wasn't set. Port maintainers
+    which want to enable this filter have to set IP_SOF_BROADCAST=1 in opt.h.
+    If you want this option also filter broadcast on recv operations, you also
+    have to set IP_SOF_BROADCAST_RECV=1 in opt.h.
+
+  2009-04-28 Simon Goldschmidt, Jakob Stoklund Olesen
+  * dhcp.c: patch #6721, bugs #25575, #25576: Some small fixes to DHCP and
+    DHCP/AUTOIP cooperation
+
+  2009-04-25 Simon Goldschmidt, Oleg Tyshev
+  * tcp_out.c: bug #24212: Deadlocked tcp_retransmit due to exceeded pcb->cwnd
+    Fixed by sorting the unsent and unacked queues (segments are inserted at the
+    right place in tcp_output and tcp_rexmit).
+
+  2009-04-25 Simon Goldschmidt
+  * memp.c, mem.c, memp.h, mem_std.h: bug #26213 "Problem with memory allocation
+    when debugging": memp_sizes contained the wrong sizes (including sanity
+    regions); memp pools for MEM_USE_POOLS were too small
+
+  2009-04-24 Simon Goldschmidt, Frédéric Bernon
+  * inet.c: patch #6765: Fix a small problem with the last changes (incorrect
+    behavior, with with ip address string not ended by a '\0', a space or a
+    end of line)
+
+  2009-04-19 Simon Goldschmidt
+  * rawapi.txt: Fixed bug #26069: Corrected documentation: if tcp_connect fails,
+    pcb->err is called, not pcb->connected (with an error code).
+
+  2009-04-19 Simon Goldschmidt
+  * tcp_out.c: Fixed bug #26236: "TCP options (timestamp) don't work with
+    no-copy-tcpwrite": deallocate option data, only concat segments with same flags
+
+  2009-04-19 Simon Goldschmidt
+  * tcp_out.c: Fixed bug #25094: "Zero-length pbuf" (options are now allocated
+    in the header pbuf, not the data pbuf)
+
+  2009-04-18 Simon Goldschmidt
+  * api_msg.c: fixed bug #25695: Segmentation fault in do_writemore()
+
+  2009-04-15 Simon Goldschmidt
+  * sockets.c: tried to fix bug #23559: lwip_recvfrom problem with tcp
+
+  2009-04-15 Simon Goldschmidt
+  * dhcp.c: task #9192: mem_free of dhcp->options_in and dhcp->msg_in
+
+  2009-04-15 Simon Goldschmidt
+  * ip.c, ip6.c, tcp_out.c, ip.h: patch #6808: Add a utility function
+    ip_hinted_output() (for smaller code mainly)
+
+  2009-04-15 Simon Goldschmidt
+  * inet.c: patch #6765: Supporting new line characters in inet_aton()
+
+  2009-04-15 Simon Goldschmidt
+  * dhcp.c: patch #6764: DHCP rebind and renew did not send hostnam option;
+    Converted constant OPTION_MAX_MSG_SIZE to netif->mtu, check if netif->mtu
+    is big enough in dhcp_start
+
+  2009-04-15 Simon Goldschmidt
+  * netbuf.c: bug #26027: netbuf_chain resulted in pbuf memory leak
+
+  2009-04-15 Simon Goldschmidt
+  * sockets.c, ppp.c: bug #25763: corrected 4 occurrences of SMEMCPY to MEMCPY
+
+  2009-04-15 Simon Goldschmidt
+  * sockets.c: bug #26121: set_errno can be overridden
+
+  2009-04-09 Kieran Mansley (patch from Luca Ceresoli <lucaceresoli>)
+  * init.c, opt.h: Patch#6774 TCP_QUEUE_OOSEQ breaks compilation when
+    LWIP_TCP==0
+
+  2009-04-09 Kieran Mansley (patch from Roy Lee <roylee17>)
+  * tcp.h: Patch#6802 Add do-while-clauses to those function like
+    macros in tcp.h
+
+  2009-03-31 Kieran Mansley
+  * tcp.c, tcp_in.c, tcp_out.c, tcp.h, opt.h: Rework the way window
+    updates are calculated and sent (BUG20515)
+
+  * tcp_in.c: cope with SYN packets received during established states,
+    and retransmission of initial SYN.
+
+  * tcp_out.c: set push bit correctly when tcp segments are merged
+
+  2009-03-27 Kieran Mansley
+  * tcp_out.c set window correctly on probes (correcting change made
+    yesterday)
+
+  2009-03-26 Kieran Mansley
+  * tcp.c, tcp_in.c, tcp.h: add tcp_abandon() to cope with dropping
+    connections where no reset required (bug #25622)
+
+  * tcp_out.c: set TCP_ACK flag on keepalive and zero window probes 
+    (bug #20779)
+
+  2009-02-18 Simon Goldschmidt (Jonathan Larmour and Bill Auerbach)
+  * ip_frag.c: patch #6528: the buffer used for IP_FRAG_USES_STATIC_BUF could be
+    too small depending on MEM_ALIGNMENT
+
+  2009-02-16 Simon Goldschmidt
+  * sockets.h/.c, api_*.h/.c: fixed arguments of socket functions to match the standard;
+    converted size argument of netconn_write to 'size_t'
+
+  2009-02-16 Simon Goldschmidt
+  * tcp.h, tcp.c: fixed bug #24440: TCP connection close problem on 64-bit host
+    by moving accept callback function pointer to TCP_PCB_COMMON
+
+  2009-02-12 Simon Goldschmidt
+  * dhcp.c: fixed bug #25345 (DHCPDECLINE is sent with "Maximum message size"
+    option)
+
+  2009-02-11 Simon Goldschmidt
+  * dhcp.c: fixed bug #24480 (releasing old udp_pdb and pbuf in dhcp_start)
+
+  2009-02-11 Simon Goldschmidt
+  * opt.h, api_msg.c: added configurable default valud for netconn->recv_bufsize:
+    RECV_BUFSIZE_DEFAULT (fixes bug #23726: pbuf pool exhaustion on slow recv())
+
+  2009-02-10 Simon Goldschmidt
+  * tcp.c: fixed bug #25467: Listen backlog is not reset on timeout in SYN_RCVD:
+    Accepts_pending is decrease on a corresponding listen pcb when a connection
+    in state SYN_RCVD is close.
+
+  2009-01-28 Jonathan Larmour
+  * pbuf.c: reclaim pbufs from TCP out-of-sequence segments if we run
+    out of pool pbufs.
+
+  2008-12-19 Simon Goldschmidt
+  * many files: patch #6699: fixed some warnings on platform where sizeof(int) == 2 
+
+  2008-12-10 Tamas Somogyi, Frédéric Bernon
+  * sockets.c: fixed bug #25051: lwip_recvfrom problem with udp: fromaddr and
+    port uses deleted netbuf.
+
+  2008-10-18 Simon Goldschmidt
+  * tcp_in.c: fixed bug ##24596: Vulnerability on faulty TCP options length
+    in tcp_parseopt
+
+  2008-10-15 Simon Goldschmidt
+  * ip_frag.c: fixed bug #24517: IP reassembly crashes on unaligned IP headers
+    by packing the struct ip_reass_helper.
+
+  2008-10-03 David Woodhouse, Jonathan Larmour
+  * etharp.c (etharp_arp_input): Fix type aliasing problem copying ip address.
+
+  2008-10-02 Jonathan Larmour
+  * dns.c: Hard-code structure sizes, to avoid issues on some compilers where
+    padding is included.
+
+  2008-09-30 Jonathan Larmour
+  * sockets.c (lwip_accept): check addr isn't NULL. If it's valid, do an
+    assertion check that addrlen isn't NULL.
+
+  2008-09-30 Jonathan Larmour
+  * tcp.c: Fix bug #24227, wrong error message in tcp_bind.
+
+  2008-08-26 Simon Goldschmidt
+  * inet.h, ip_addr.h: fixed bug #24132: Cross-dependency between ip_addr.h and
+    inet.h -> moved declaration of struct in_addr from ip_addr.h to inet.h
+
+  2008-08-14 Simon Goldschmidt
+  * api_msg.c: fixed bug #23847: do_close_internal references freed memory (when
+    tcp_close returns != ERR_OK)
+
+  2008-07-08 Frédéric Bernon
+  * stats.h: Fix some build bugs introduced with patch #6483 (missing some parameters
+    in macros, mainly if MEM_STATS=0 and MEMP_STATS=0).
+
+  2008-06-24 Jonathan Larmour
+  * tcp_in.c: Fix for bug #23693 as suggested by Art R. Ensure cseg is unused
+    if tcp_seg_copy fails.
+
+  2008-06-17 Simon Goldschmidt
+  * inet_chksum.c: Checked in some ideas of patch #6460 (loop optimizations)
+    and created defines for swapping bytes and folding u32 to u16.
+
+  2008-05-30 Kieran Mansley
+  * tcp_in.c Remove redundant "if" statement, and use real rcv_wnd
+    rather than rcv_ann_wnd when deciding if packets are in-window.
+    Contributed by <arasmussen@consultant.datasys.swri.edu>
+
+  2008-05-30 Kieran Mansley
+  * mem.h: Fix BUG#23254.  Change macro definition of mem_* to allow
+    passing as function pointers when MEM_LIBC_MALLOC is defined.
+
+  2008-05-09 Jonathan Larmour
+  * err.h, err.c, sockets.c: Fix bug #23119: Reorder timeout error code to
+    stop it being treated as a fatal error.
+
+  2008-04-15 Simon Goldschmidt
+  * dhcp.c: fixed bug #22804: dhcp_stop doesn't clear NETIF_FLAG_DHCP
+    (flag now cleared)
+
+  2008-03-27 Simon Goldschmidt
+  * mem.c, tcpip.c, tcpip.h, opt.h: fixed bug #21433 (Calling mem_free/pbuf_free
+    from interrupt context isn't safe): set LWIP_USE_HEAP_FROM_INTERRUPT to 1
+    in lwipopts.h or use pbuf_free_callback(p)/mem_free_callback(m) to free pbufs
+    or heap memory from interrupt context
+
+  2008-03-26 Simon Goldschmidt
+  * tcp_in.c, tcp.c: fixed bug #22249: division by zero could occur if a remote
+    host sent a zero mss as TCP option.
+
+
+(STABLE-1.3.0)
+
+  ++ New features:
+
+  2008-03-10 Jonathan Larmour
+  * inet_chksum.c: Allow choice of one of the sample algorithms to be
+    made from lwipopts.h. Fix comment on how to override LWIP_CHKSUM.
+
+  2008-01-22 Frédéric Bernon
+  * tcp.c, tcp_in.c, tcp.h, opt.h: Rename LWIP_CALCULATE_EFF_SEND_MSS in 
+    TCP_CALCULATE_EFF_SEND_MSS to have coherent TCP options names.
+
+  2008-01-14 Frédéric Bernon
+  * rawapi.txt, api_msg.c, tcp.c, tcp_in.c, tcp.h: changes for task #7675 "Enable
+    to refuse data on a TCP_EVENT_RECV call". Important, behavior changes for the
+    tcp_recv callback (see rawapi.txt).
+
+  2008-01-14 Frédéric Bernon, Marc Chaland
+  * ip.c: Integrate patch #6369" ip_input : checking before realloc".
+  
+  2008-01-12 Frédéric Bernon
+  * tcpip.h, tcpip.c, api.h, api_lib.c, api_msg.c, sockets.c: replace the field
+    netconn::sem per netconn::op_completed like suggested for the task #7490
+    "Add return value to sys_mbox_post".
+
+  2008-01-12 Frédéric Bernon
+  * api_msg.c, opt.h: replace DEFAULT_RECVMBOX_SIZE per DEFAULT_TCP_RECVMBOX_SIZE,
+    DEFAULT_UDP_RECVMBOX_SIZE and DEFAULT_RAW_RECVMBOX_SIZE (to optimize queues
+    sizes), like suggested for the task #7490 "Add return value to sys_mbox_post".
+
+  2008-01-10 Frédéric Bernon
+  * tcpip.h, tcpip.c: add tcpip_callback_with_block function for the task #7490
+    "Add return value to sys_mbox_post". tcpip_callback is always defined as
+    "blocking" ("block" parameter = 1).
+
+  2008-01-10 Frédéric Bernon
+  * tcpip.h, tcpip.c, api.h, api_lib.c, api_msg.c, sockets.c: replace the field
+    netconn::mbox (sys_mbox_t) per netconn::sem (sys_sem_t) for the task #7490
+    "Add return value to sys_mbox_post".
+
+  2008-01-05 Frédéric Bernon
+  * sys_arch.txt, api.h, api_lib.c, api_msg.h, api_msg.c, tcpip.c, sys.h, opt.h:
+    Introduce changes for task #7490 "Add return value to sys_mbox_post" with some
+    modifications in the sys_mbox api: sys_mbox_new take a "size" parameters which
+    indicate the number of pointers query by the mailbox. There is three defines
+    in opt.h to indicate sizes for tcpip::mbox, netconn::recvmbox, and for the 
+    netconn::acceptmbox. Port maintainers, you can decide to just add this new 
+    parameter in your implementation, but to ignore it to keep the previous behavior.
+    The new sys_mbox_trypost function return a value to know if the mailbox is
+    full or if the message is posted. Take a look to sys_arch.txt for more details.
+    This new function is used in tcpip_input (so, can be called in an interrupt
+    context since the function is not blocking), and in recv_udp and recv_raw.
+
+  2008-01-04 Frédéric Bernon, Simon Goldschmidt, Jonathan Larmour
+  * rawapi.txt, api.h, api_lib.c, api_msg.h, api_msg.c, sockets.c, tcp.h, tcp.c,
+    tcp_in.c, init.c, opt.h: rename backlog options with TCP_ prefix, limit the
+    "backlog" parameter in an u8_t, 0 is interpreted as "smallest queue", add
+    documentation in the rawapi.txt file.
+
+  2007-12-31 Kieran Mansley (based on patch from Per-Henrik Lundbolm)
+  * tcp.c, tcp_in.c, tcp_out.c, tcp.h: Add TCP persist timer
+
+  2007-12-31 Frédéric Bernon, Luca Ceresoli
+  * autoip.c, etharp.c: ip_addr.h: Integrate patch #6348: "Broadcast ARP packets
+    in autoip". The change in etharp_raw could be removed, since all calls to
+    etharp_raw use ethbroadcast for the "ethdst_addr" parameter. But it could be
+    wrong in the future.
+
+  2007-12-30 Frédéric Bernon, Tom Evans
+  * ip.c: Fix bug #21846 "LwIP doesn't appear to perform any IP Source Address
+    Filtering" reported by Tom Evans.
+
+  2007-12-21 Frédéric Bernon, Simon Goldschmidt, Jonathan Larmour
+  * tcp.h, opt.h, api.h, api_msg.h, tcp.c, tcp_in.c, api_lib.c, api_msg.c,
+    sockets.c, init.c: task #7252: Implement TCP listen backlog: Warning: raw API
+    applications have to call 'tcp_accepted(pcb)' in their accept callback to
+    keep accepting new connections.
+
+  2007-12-13 Frédéric Bernon
+  * api_msg.c, err.h, err.c, sockets.c, dns.c, dns.h: replace "enum dns_result"
+    by err_t type. Add a new err_t code "ERR_INPROGRESS".
+
+  2007-12-12 Frédéric Bernon
+  * dns.h, dns.c, opt.h: move DNS options to the "right" place. Most visibles
+    are the one which have ram usage.
+
+  2007-12-05 Frédéric Bernon
+  * netdb.c: add a LWIP_DNS_API_HOSTENT_STORAGE option to decide to use a static
+    set of variables (=0) or a local one (=1). In this last case, your port should
+    provide a function "struct hostent* sys_thread_hostent( struct hostent* h)"
+    which have to do a copy of "h" and return a pointer ont the "per-thread" copy.
+
+  2007-12-03 Simon Goldschmidt
+  * ip.c: ip_input: check if a packet is for inp first before checking all other
+    netifs on netif_list (speeds up packet receiving in most cases)
+
+  2007-11-30 Simon Goldschmidt
+  * udp.c, raw.c: task #7497: Sort lists (pcb, netif, ...) for faster access
+    UDP: move a (connected) pcb selected for input to the front of the list of
+    pcbs so that it is found faster next time. Same for RAW pcbs that have eaten
+    a packet.
+
+  2007-11-28 Simon Goldschmidt
+  * etharp.c, stats.c, stats.h, opt.h: Introduced ETHARP_STATS
+
+  2007-11-25 Simon Goldschmidt
+  * dhcp.c: dhcp_unfold_reply() uses pbuf_copy_partial instead of its own copy
+    algorithm.
+
+  2007-11-24 Simon Goldschmidt
+  * netdb.h, netdb.c, sockets.h/.c: Moved lwip_gethostbyname from sockets.c
+    to the new file netdb.c; included lwip_getaddrinfo.
+
+  2007-11-21 Simon Goldschmidt
+  * tcp.h, opt.h, tcp.c, tcp_in.c: implemented calculating the effective send-mss
+    based on the MTU of the netif used to send. Enabled by default. Disable by
+    setting LWIP_CALCULATE_EFF_SEND_MSS to 0. This fixes bug #21492.
+
+  2007-11-19 Frédéric Bernon
+  * api_msg.c, dns.h, dns.c: Implement DNS_DOES_NAME_CHECK option (check if name
+    received match the name query), implement DNS_USES_STATIC_BUF (the place where
+    copy dns payload to parse the response), return an error if there is no place
+    for a new query, and fix some minor problems.
+
+  2007-11-16 Simon Goldschmidt
+  * new files: ipv4/inet.c, ipv4/inet_chksum.c, ipv6/inet6.c
+    removed files: core/inet.c, core/inet6.c
+    Moved inet files into ipv4/ipv6 directory; splitted inet.c/inet.h into
+    inet and chksum part; changed includes in all lwIP files as appropriate
+
+  2007-11-16 Simon Goldschmidt
+  * api.h, api_msg.h, api_lib.c, api_msg.c, socket.h, socket.c: Added sequential
+    dns resolver function for netconn api (netconn_gethostbyname) and socket api
+    (gethostbyname/gethostbyname_r).
+
+  2007-11-15 Jim Pettinato, Frédéric Bernon
+  * opt.h, init.c, tcpip.c, dhcp.c, dns.h, dns.c: add DNS client for simple name
+    requests with RAW api interface. Initialization is done in lwip_init() with
+    build time options. DNS timer is added in tcpip_thread context. DHCP can set
+    DNS server ip addresses when options are received. You need to set LWIP_DNS=1
+    in your lwipopts.h file (LWIP_DNS=0 in opt.h). DNS_DEBUG can be set to get
+    some traces with LWIP_DEBUGF. Sanity check have been added. There is a "todo"
+    list with points to improve.
+
+  2007-11-06 Simon Goldschmidt
+  * opt.h, mib2.c: Patch #6215: added ifAdminStatus write support (if explicitly
+    enabled by defining SNMP_SAFE_REQUESTS to 0); added code to check link status
+    for ifOperStatus if LWIP_NETIF_LINK_CALLBACK is defined.
+
+  2007-11-06 Simon Goldschmidt
+  * api.h, api_msg.h and dependent files: Task #7410: Removed the need to include
+    core header files in api.h (ip/tcp/udp/raw.h) to hide the internal
+    implementation from netconn api applications.
+
+  2007-11-03 Frédéric Bernon
+  * api.h, api_lib.c, api_msg.c, sockets.c, opt.h: add SO_RCVBUF option for UDP &
+    RAW netconn. You need to set LWIP_SO_RCVBUF=1 in your lwipopts.h (it's disabled
+    by default). Netconn API users can use the netconn_recv_bufsize macro to access
+    it. This is a first release which have to be improve for TCP. Note it used the
+    netconn::recv_avail which need to be more "thread-safe" (note there is already
+    the problem for FIONREAD with lwip_ioctl/ioctlsocket).
+
+  2007-11-01 Frédéric Bernon, Marc Chaland
+  * sockets.h, sockets.c, api.h, api_lib.c, api_msg.h, api_msg.c, tcp.h, tcp_out.c:
+    Integrate "patch #6250 : MSG_MORE flag for send". MSG_MORE is used at socket api
+    layer, NETCONN_MORE at netconn api layer, and TCP_WRITE_FLAG_MORE at raw api
+    layer. This option enable to delayed TCP PUSH flag on multiple "write" calls.
+    Note that previous "copy" parameter for "write" APIs is now called "apiflags".
+
+  2007-10-24 Frédéric Bernon
+  * api.h, api_lib.c, api_msg.c: Add macro API_EVENT in the same spirit than 
+    TCP_EVENT_xxx macros to get a code more readable. It could also help to remove
+    some code (like we have talk in "patch #5919 : Create compile switch to remove
+    select code"), but it could be done later.
+
+  2007-10-08 Simon Goldschmidt
+  * many files: Changed initialization: many init functions are not needed any
+    more since we now rely on the compiler initializing global and static
+    variables to zero!
+
+  2007-10-06 Simon Goldschmidt
+  * ip_frag.c, memp.c, mib2.c, ip_frag.h, memp_std.h, opt.h: Changed IP_REASSEMBLY
+    to enqueue the received pbufs so that multiple packets can be reassembled
+    simultaneously and no static reassembly buffer is needed.
+
+  2007-10-05 Simon Goldschmidt
+  * tcpip.c, etharp.h, etharp.c: moved ethernet_input from tcpip.c to etharp.c so
+    all netifs (or ports) can use it.
+
+  2007-10-05 Frédéric Bernon
+  * netifapi.h, netifapi.c: add function netifapi_netif_set_default. Change the 
+    common function to reduce a little bit the footprint (for all functions using
+    only the "netif" parameter).
+
+  2007-10-03 Frédéric Bernon
+  * netifapi.h, netifapi.c: add functions netifapi_netif_set_up, netifapi_netif_set_down,
+    netifapi_autoip_start and netifapi_autoip_stop. Use a common function to reduce
+    a little bit the footprint (for all functions using only the "netif" parameter).
+
+  2007-09-15 Frédéric Bernon
+  * udp.h, udp.c, sockets.c: Changes for "#20503 IGMP Improvement". Add IP_MULTICAST_IF
+    option in socket API, and a new field "multicast_ip" in "struct udp_pcb" (for
+    netconn and raw API users), only if LWIP_IGMP=1. Add getsockopt processing for
+    IP_MULTICAST_TTL and IP_MULTICAST_IF.
+
+  2007-09-10 Frédéric Bernon
+  * snmp.h, mib2.c: enable to remove SNMP timer (which consumne several cycles
+    even when it's not necessary). snmp_agent.txt tell to call snmp_inc_sysuptime()
+    each 10ms (but, it's intrusive if you use sys_timeout feature). Now, you can
+    decide to call snmp_add_sysuptime(100) each 1000ms (which is bigger "step", but
+    call to a lower frequency). Or, you can decide to not call snmp_inc_sysuptime()
+    or snmp_add_sysuptime(), and to define the SNMP_GET_SYSUPTIME(sysuptime) macro.
+    This one is undefined by default in mib2.c. SNMP_GET_SYSUPTIME is called inside
+    snmp_get_sysuptime(u32_t *value), and enable to change "sysuptime" value only
+    when it's queried (any direct call to "sysuptime" is changed by a call to 
+    snmp_get_sysuptime).
+
+  2007-09-09 Frédéric Bernon, Bill Florac
+  * igmp.h, igmp.c, netif.h, netif.c, ip.c: To enable to have interfaces with IGMP,
+    and others without it, there is a new NETIF_FLAG_IGMP flag to set in netif->flags
+    if you want IGMP on an interface. igmp_stop() is now called inside netif_remove().
+    igmp_report_groups() is now called inside netif_set_link_up() (need to have
+    LWIP_NETIF_LINK_CALLBACK=1) to resend reports once the link is up (avoid to wait
+    the next query message to receive the matching multicast streams).
+
+  2007-09-08 Frédéric Bernon
+  * sockets.c, ip.h, api.h, tcp.h: declare a "struct ip_pcb" which only contains
+    IP_PCB. Add in the netconn's "pcb" union a "struct ip_pcb *ip;" (no size change).
+    Use this new field to access to common pcb fields (ttl, tos, so_options, etc...).
+    Enable to access to these fields with LWIP_TCP=0.
+
+  2007-09-05 Frédéric Bernon
+  * udp.c, ipv4/icmp.c, ipv4/ip.c, ipv6/icmp.c, ipv6/ip6.c, ipv4/icmp.h,
+    ipv6/icmp.h, opt.h: Integrate "task #7272 : LWIP_ICMP option". The new option
+    LWIP_ICMP enable/disable ICMP module inside the IP stack (enable per default).
+    Be careful, disabling ICMP make your product non-compliant to RFC1122, but
+    help to reduce footprint, and to reduce "visibility" on the Internet.
+
+  2007-09-05 Frédéric Bernon, Bill Florac
+  * opt.h, sys.h, tcpip.c, slipif.c, ppp.c, sys_arch.txt: Change parameters list
+    for sys_thread_new (see "task #7252 : Create sys_thread_new_ex()"). Two new
+    parameters have to be provided: a task name, and a task stack size. For this
+    one, since it's platform dependant, you could define the best one for you in
+    your lwipopts.h. For port maintainers, you can just add these new parameters
+    in your sys_arch.c file, and but it's not mandatory, use them in your OS
+    specific functions.
+
+  2007-09-05 Frédéric Bernon
+  * inet.c, autoip.c, msg_in.c, msg_out.c, init.c: Move some build time checkings
+    inside init.c for task #7142 "Sanity check user-configurable values".
+
+  2007-09-04 Frédéric Bernon, Bill Florac
+  * igmp.h, igmp.c, memp_std.h, memp.c, init.c, opt.h: Replace mem_malloc call by
+    memp_malloc, and use a new MEMP_NUM_IGMP_GROUP option (see opt.h to define the
+    value). It will avoid potential fragmentation problems, use a counter to know
+    how many times a group is used on an netif, and free it when all applications
+    leave it. MEMP_NUM_IGMP_GROUP got 8 as default value (and init.c got a sanity
+    check if LWIP_IGMP!=0).
+
+  2007-09-03 Frédéric Bernon
+  * igmp.h, igmp.c, sockets.c, api_msg.c: Changes for "#20503 IGMP Improvement".
+    Initialize igmp_mac_filter to NULL in netif_add (this field should be set in
+    the netif's "init" function). Use the "imr_interface" field (for socket layer)
+    and/or the "interface" field (for netconn layer), for join/leave operations.
+    The igmp_join/leavegroup first parameter change from a netif to an ipaddr.
+    This field could be a netif's ipaddr, or "any" (same meaning than ip_addr_isany).
+
+  2007-08-30 Frédéric Bernon
+  * Add netbuf.h, netbuf.c, Change api.h, api_lib.c: #7249 "Split netbuf functions
+    from api/api_lib". Now netbuf API is independant of netconn, and can be used
+    with other API (application based on raw API, or future "socket2" API). Ports
+    maintainers just have to add src/api/netbuf.c in their makefile/projects.
+
+  2007-08-30 Frédéric Bernon, Jonathan Larmour
+  * init.c: Add first version of lwip_sanity_check for task #7142 "Sanity check
+    user-configurable values".
+
+  2007-08-29 Frédéric Bernon
+  * igmp.h, igmp.c, tcpip.c, init.c, netif.c: change igmp_init and add igmp_start.
+    igmp_start is call inside netif_add. Now, igmp initialization is in the same
+    spirit than the others modules. Modify some IGMP debug traces.
+
+  2007-08-29 Frédéric Bernon
+  * Add init.h, init.c, Change opt.h, tcpip.c: Task  #7213 "Add a lwip_init function"
+    Add lwip_init function to regroup all modules initializations, and to provide
+    a place to add code for task #7142 "Sanity check user-configurable values".
+    Ports maintainers should remove direct initializations calls from their code,
+    and add init.c in their makefiles. Note that lwip_init() function is called
+    inside tcpip_init, but can also be used by raw api users since all calls are
+    disabled when matching options are disabled. Also note that their is new options
+    in opt.h, you should configure in your lwipopts.h (they are enabled per default).
+
+  2007-08-26 Marc Boucher
+  * api_msg.c: do_close_internal(): Reset the callbacks and arg (conn) to NULL
+    since they can under certain circumstances be called with an invalid conn
+    pointer after the connection has been closed (and conn has been freed). 
+
+  2007-08-25 Frédéric Bernon (Artem Migaev's Patch)
+  * netif.h, netif.c: Integrate "patch #6163 : Function to check if link layer is up".
+    Add a netif_is_link_up() function if LWIP_NETIF_LINK_CALLBACK option is set.
+
+  2007-08-22 Frédéric Bernon
+  * netif.h, netif.c, opt.h: Rename LWIP_NETIF_CALLBACK in LWIP_NETIF_STATUS_CALLBACK
+    to be coherent with new LWIP_NETIF_LINK_CALLBACK option before next release.
+
+  2007-08-22 Frédéric Bernon
+  * tcpip.h, tcpip.c, ethernetif.c, opt.h: remove options ETHARP_TCPIP_INPUT &
+    ETHARP_TCPIP_ETHINPUT, now, only "ethinput" code is supported, even if the 
+    name is tcpip_input (we keep the name of 1.2.0 function).
+
+  2007-08-17 Jared Grubb
+  * memp_std.h, memp.h, memp.c, mem.c, stats.c: (Task #7136) Centralize mempool 
+    settings into new memp_std.h and optional user file lwippools.h. This adds
+    more dynamic mempools, and allows the user to create an arbitrary number of
+    mempools for mem_malloc.
+
+  2007-08-16 Marc Boucher
+  * api_msg.c: Initialize newconn->state to NETCONN_NONE in accept_function;
+    otherwise it was left to NETCONN_CLOSE and sent_tcp() could prematurely
+    close the connection.
+
+  2007-08-16 Marc Boucher
+  * sockets.c: lwip_accept(): check netconn_peer() error return.
+
+  2007-08-16 Marc Boucher
+  * mem.c, mem.h: Added mem_calloc().
+
+  2007-08-16 Marc Boucher
+  * tcpip.c, tcpip.h memp.c, memp.h: Added distinct memp (MEMP_TCPIP_MSG_INPKT)
+    for input packets to prevent floods from consuming all of MEMP_TCPIP_MSG
+    and starving other message types.
+    Renamed MEMP_TCPIP_MSG to MEMP_TCPIP_MSG_API
+
+  2007-08-16 Marc Boucher
+  * pbuf.c, pbuf.h, etharp.c, tcp_in.c, sockets.c: Split pbuf flags in pbuf
+    type and flgs (later renamed to flags).
+    Use enum pbuf_flag as pbuf_type.  Renumber PBUF_FLAG_*.
+    Improved lwip_recvfrom().  TCP push now propagated.
+
+  2007-08-16 Marc Boucher
+  * ethernetif.c, contrib/ports/various: ethbroadcast now a shared global
+    provided by etharp.
+
+  2007-08-16 Marc Boucher
+  * ppp_oe.c ppp_oe.h, auth.c chap.c fsm.c lcp.c ppp.c ppp.h,
+    etharp.c ethernetif.c, etharp.h, opt.h tcpip.h, tcpip.c:
+    Added PPPoE support and various PPP improvements.
+
+  2007-07-25 Simon Goldschmidt
+  * api_lib.c, ip_frag.c, pbuf.c, api.h, pbuf.h: Introduced pbuf_copy_partial,
+    making netbuf_copy_partial use this function.
+
+  2007-07-25 Simon Goldschmidt
+  * tcp_in.c: Fix bug #20506: Slow start / initial congestion window starts with
+    2 * mss (instead of 1 * mss previously) to comply with some newer RFCs and
+    other stacks.
+
+  2007-07-13 Jared Grubb (integrated by Frédéric Bernon)
+  * opt.h, netif.h, netif.c, ethernetif.c: Add new configuration option to add
+    a link callback in the netif struct, and functions to handle it. Be carefull
+    for port maintainers to add the NETIF_FLAG_LINK_UP flag (like in ethernetif.c)
+    if you want to be sure to be compatible with future changes...
+
+  2007-06-30 Frédéric Bernon
+  * sockets.h, sockets.c: Implement MSG_PEEK flag for recv/recvfrom functions.
+
+  2007-06-21 Simon Goldschmidt
+  * etharp.h, etharp.c: Combined etharp_request with etharp_raw for both
+    LWIP_AUTOIP =0 and =1 to remove redundant code.
+
+  2007-06-21 Simon Goldschmidt
+  * mem.c, memp.c, mem.h, memp.h, opt.h: task #6863: Introduced the option
+    MEM_USE_POOLS to use 4 pools with different sized elements instead of a
+    heap. This both prevents memory fragmentation and gives a higher speed
+    at the cost of more memory consumption. Turned off by default.
+
+  2007-06-21 Simon Goldschmidt
+  * api_lib.c, api_msg.c, api.h, api_msg.h: Converted the length argument of
+    netconn_write (and therefore also api_msg_msg.msg.w.len) from u16_t into
+    int to be able to send a bigger buffer than 64K with one time (mainly
+    used from lwip_send).
+
+  2007-06-21 Simon Goldschmidt
+  * tcp.h, api_msg.c: Moved the nagle algorithm from netconn_write/do_write
+    into a define (tcp_output_nagle) in tcp.h to provide it to raw api users, too.
+
+  2007-06-21 Simon Goldschmidt
+  * api.h, api_lib.c, api_msg.c: Fixed bug #20021: Moved sendbuf-processing in
+    netconn_write from api_lib.c to api_msg.c to also prevent multiple context-
+    changes on low memory or empty send-buffer.
+
+  2007-06-18 Simon Goldschmidt
+  * etharp.c, etharp.h: Changed etharp to use a defined hardware address length
+    of 6 to avoid loading netif->hwaddr_len every time (since this file is only
+    used for ethernet and struct eth_addr already had a defined length of 6).
+
+  2007-06-17 Simon Goldschmidt
+  * sockets.c, sockets.h: Implemented socket options SO_NO_CHECK for UDP sockets
+    to disable UDP checksum generation on transmit.
+
+  2007-06-13 Frédéric Bernon, Simon Goldschmidt
+  * debug.h, api_msg.c: change LWIP_ERROR to use it to check errors like invalid
+    pointers or parameters, and let the possibility to redefined it in cc.h. Use
+    this macro to check "conn" parameter in api_msg.c functions.
+
+  2007-06-11 Simon Goldschmidt
+  * sockets.c, sockets.h: Added UDP lite support for sockets
+
+  2007-06-10 Simon Goldschmidt
+  * udp.h, opt.h, api_msg.c, ip.c, udp.c: Included switch LWIP_UDPLITE (enabled
+    by default) to switch off UDP-Lite support if not needed (reduces udp.c code
+    size)
+
+  2007-06-09 Dominik Spies (integrated by Frédéric Bernon)
+  * autoip.h, autoip.c, dhcp.h, dhcp.c, netif.h, netif.c, etharp.h, etharp.c, opt.h:
+    AutoIP implementation available for IPv4, with new options LWIP_AUTOIP and
+    LWIP_DHCP_AUTOIP_COOP if you want to cooperate with DHCP. Some tips to adapt
+    (see TODO mark in the source code).
+
+  2007-06-09 Simon Goldschmidt
+  * etharp.h, etharp.c, ethernetif.c: Modified order of parameters for
+    etharp_output() to match netif->output so etharp_output() can be used
+    directly as netif->output to save one function call.
+
+  2007-06-08 Simon Goldschmidt
+  * netif.h, ethernetif.c, slipif.c, loopif.c: Added define
+    NETIF_INIT_SNMP(netif, type, speed) to initialize per-netif snmp variables,
+    added initialization of those to ethernetif, slipif and loopif.
+
+  2007-05-18 Simon Goldschmidt
+  * opt.h, ip_frag.c, ip_frag.h, ip.c: Added option IP_FRAG_USES_STATIC_BUF
+    (defaulting to off for now) that can be set to 0 to send fragmented
+    packets by passing PBUF_REFs down the stack.
+
+  2007-05-23 Frédéric Bernon
+  * api_lib.c: Implement SO_RCVTIMEO for accept and recv on TCP
+    connections, such present in patch #5959.
+
+  2007-05-23 Frédéric Bernon
+  * api.h, api_lib.c, api_msg.c, sockets.c: group the different NETCONN_UDPxxx
+    code in only one part...
+
+  2007-05-18 Simon Goldschmidt
+  * opt.h, memp.h, memp.c: Added option MEMP_OVERFLOW_CHECK to check for memp
+    elements to overflow. This is achieved by adding some bytes before and after
+    each pool element (increasing their size, of course), filling them with a
+    prominent value and checking them on freeing the element.
+    Set it to 2 to also check every element in every pool each time memp_malloc()
+    or memp_free() is called (slower but more helpful).
+
+  2007-05-10 Simon Goldschmidt
+  * opt.h, memp.h, memp.c, pbuf.c (see task #6831): use a new memp pool for
+    PBUF_POOL pbufs instead of the old pool implementation in pbuf.c to reduce
+    code size.
+
+  2007-05-11 Frédéric Bernon
+  * sockets.c, api_lib.c, api_msg.h, api_msg.c, netifapi.h, netifapi.c, tcpip.c:
+    Include a function pointer instead of a table index in the message to reduce
+    footprint. Disable some part of lwip_send and lwip_sendto if some options are
+    not set (LWIP_TCP, LWIP_UDP, LWIP_RAW).
+
+  2007-05-10 Simon Goldschmidt
+  * *.h (except netif/ppp/*.h): Included patch #5448: include '#ifdef __cplusplus
+    \ extern "C" {' in all header files. Now you can write your application using
+    the lwIP stack in C++ and simply #include the core files. Note I have left
+    out the netif/ppp/*h header files for now, since I don't know which files are
+    included by applications and which are for internal use only.
+
+  2007-05-09 Simon Goldschmidt
+  * opt.h, *.c/*.h: Included patch #5920: Create define to override C-library
+    memcpy. 2 Defines are created: MEMCPY() for normal memcpy, SMEMCPY() for
+    situations where some compilers might inline the copy and save a function
+    call. Also replaced all calls to memcpy() with calls to (S)MEMCPY().
+
+  2007-05-08 Simon Goldschmidt
+  * mem.h: If MEM_LIBC_MALLOC==1, allow the defines (e.g. mem_malloc() -> malloc())
+    to be overriden in case the C-library malloc implementation is not protected
+    against concurrent access.
+
+  2007-05-04 Simon Goldschmidt (Atte Kojo)
+  * etharp.c: Introduced fast one-entry-cache to speed up ARP lookup when sending
+    multiple packets to the same host.
+
+  2007-05-04 Frédéric Bernon, Jonathan Larmour
+  * sockets.c, api.h, api_lib.c, api_msg.h, api_msg.c: Fix bug #19162 "lwip_sento: a possible
+    to corrupt remote addr/port connection state". Reduce problems "not enought memory" with
+    netbuf (if we receive lot of datagrams). Improve lwip_sendto (only one exchange between
+    sockets api and api_msg which run in tcpip_thread context). Add netconn_sento function.
+    Warning, if you directly access to "fromaddr" & "fromport" field from netbuf struct,
+    these fields are now renamed "addr" & "port".
+
+  2007-04-11 Jonathan Larmour
+  * sys.h, api_lib.c: Provide new sys_mbox_tryfetch function. Require ports to provide new
+    sys_arch_mbox_tryfetch function to get a message if one is there, otherwise return
+    with SYS_MBOX_EMPTY. sys_arch_mbox_tryfetch can be implemented as a function-like macro
+    by the port in sys_arch.h if desired.
+
+  2007-04-06 Frédéric Bernon, Simon Goldschmidt
+  * opt.h, tcpip.h, tcpip.c, netifapi.h, netifapi.c: New configuration option LWIP_NETIF_API
+    allow to use thread-safe functions to add/remove netif in list, and to start/stop dhcp
+    clients, using new functions from netifapi.h. Disable as default (no port change to do).
+
+  2007-04-05 Frédéric Bernon
+  * sockets.c: remplace ENOBUFS errors on alloc_socket by ENFILE to be more BSD compliant.
+
+  2007-04-04 Simon Goldschmidt
+  * arch.h, api_msg.c, dhcp.c, msg_in.c, sockets.c: Introduced #define LWIP_UNUSED_ARG(x)
+    use this for and architecture-independent form to tell the compiler you intentionally
+    are not using this variable. Can be overriden in cc.h.
+
+  2007-03-28 Frédéric Bernon
+  * opt.h, netif.h, dhcp.h, dhcp.c: New configuration option LWIP_NETIF_HOSTNAME allow to
+    define a hostname in netif struct (this is just a pointer, so, you can use a hardcoded
+    string, point on one of your's ethernetif field, or alloc a string you will free yourself).
+    It will be used by DHCP to register a client hostname, but can also be use when you call
+    snmp_set_sysname.
+
+  2007-03-28 Frédéric Bernon
+  * netif.h, netif.c: A new NETIF_FLAG_ETHARP flag is defined in netif.h, to allow to 
+    initialize a network interface's flag with. It tell this interface is an ethernet
+    device, and we can use ARP with it to do a "gratuitous ARP" (RFC 3220 "IP Mobility
+    Support for IPv4" section 4.6) when interface is "up" with netif_set_up().
+
+  2007-03-26 Frédéric Bernon, Jonathan Larmour
+  * opt.h, tcpip.c: New configuration option LWIP_ARP allow to disable ARP init at build
+    time if you only use PPP or SLIP. The default is enable. Note we don't have to call 
+    etharp_init in your port's initilization sequence if you use tcpip.c, because this call
+    is done in tcpip_init function.
+
+  2007-03-22 Frédéric Bernon
+  * stats.h, stats.c, msg_in.c: Stats counters can be change to u32_t if necessary with the
+    new option LWIP_STATS_LARGE. If you need this option, define LWIP_STATS_LARGE to 1 in
+    your lwipopts.h. More, unused counters are not defined in the stats structs, and not 
+    display by stats_display(). Note that some options (SYS_STATS and RAW_STATS) are defined
+    but never used. Fix msg_in.c with the correct #if test for a stat display.
+
+  2007-03-21 Kieran Mansley
+  * netif.c, netif.h: Apply patch#4197 with some changes (originator: rireland@hmgsl.com). 
+    Provides callback on netif up/down state change.
+
+  2007-03-11 Frédéric Bernon, Mace Gael, Steve Reynolds
+  * sockets.h, sockets.c, api.h, api_lib.c, api_msg.h, api_msg.c, igmp.h, igmp.c,
+    ip.c, netif.h, tcpip.c, opt.h:
+    New configuration option LWIP_IGMP to enable IGMP processing. Based on only one 
+    filter per all network interfaces. Declare a new function in netif to enable to
+    control the MAC filter (to reduce lwIP traffic processing).
+
+  2007-03-11 Frédéric Bernon
+  * tcp.h, tcp.c, sockets.c, tcp_out.c, tcp_in.c, opt.h: Keepalive values can
+    be configured at run time with LWIP_TCP_KEEPALIVE, but don't change this
+    unless you know what you're doing (default are RFC1122 compliant). Note
+    that TCP_KEEPIDLE and TCP_KEEPINTVL have to be set in seconds.
+
+  2007-03-08 Frédéric Bernon
+  * tcp.h: Keepalive values can be configured at compile time, but don't change
+    this unless you know what you're doing (default are RFC1122 compliant).
+
+  2007-03-08 Frédéric Bernon
+  * sockets.c, api.h, api_lib.c, tcpip.c, sys.h, sys.c, err.c, opt.h:
+    Implement LWIP_SO_RCVTIMEO configuration option to enable/disable SO_RCVTIMEO
+    on UDP sockets/netconn.
+
+  2007-03-08 Simon Goldschmidt
+  * snmp_msg.h, msg_in.c: SNMP UDP ports can be configured at compile time.
+
+  2007-03-06 Frédéric Bernon
+  * api.h, api_lib.c, sockets.h, sockets.c, tcpip.c, sys.h, sys.c, err.h: 
+    Implement SO_RCVTIMEO on UDP sockets/netconn.
+
+  2007-02-28 Kieran Mansley (based on patch from Simon Goldschmidt)
+  * api_lib.c, tcpip.c, memp.c, memp.h: make API msg structs allocated
+    on the stack and remove the API msg type from memp
+
+  2007-02-26 Jonathan Larmour (based on patch from Simon Goldschmidt)
+  * sockets.h, sockets.c: Move socket initialization to new
+    lwip_socket_init() function.
+    NOTE: this changes the API with ports. Ports will have to be
+    updated to call lwip_socket_init() now.
+
+  2007-02-26 Jonathan Larmour (based on patch from Simon Goldschmidt)
+  * api_lib.c: Use memcpy in netbuf_copy_partial.
+
+
+  ++ Bug fixes:
+
+  2008-03-17 Frédéric Bernon, Ed Kerekes
+  * igmp.h, igmp.c: Fix bug #22613 "IGMP iphdr problem" (could have
+    some problems to fill the IP header on some targets, use now the
+    ip.h macros to do it).
+
+  2008-03-13 Frédéric Bernon
+  * sockets.c: Fix bug #22435 "lwip_recvfrom with TCP break;". Using
+    (lwip_)recvfrom with valid "from" and "fromlen" parameters, on a
+    TCP connection caused a crash. Note that using (lwip_)recvfrom
+    like this is a bit slow and that using (lwip)getpeername is the
+    good lwip way to do it (so, using recv is faster on tcp sockets).
+
+  2008-03-12 Frédéric Bernon, Jonathan Larmour
+  * api_msg.c, contrib/apps/ping.c: Fix bug #22530 "api_msg.c's
+    recv_raw() does not consume data", and the ping sample (with
+    LWIP_SOCKET=1, the code did the wrong supposition that lwip_recvfrom
+    returned the IP payload, without the IP header).
+
+  2008-03-04 Jonathan Larmour
+  * mem.c, stats.c, mem.h: apply patch #6414 to avoid compiler errors
+  and/or warnings on some systems where mem_size_t and size_t differ.
+  * pbuf.c, ppp.c: Fix warnings on some systems with mem_malloc.
+
+  2008-03-04 Kieran Mansley (contributions by others) 
+  * Numerous small compiler error/warning fixes from contributions to
+    mailing list after 1.3.0 release candidate made.
+
+  2008-01-25 Cui hengbin (integrated by Frédéric Bernon)
+  * dns.c: Fix bug #22108 "DNS problem" caused by unaligned structures.
+
+  2008-01-15 Kieran Mansley
+  * tcp_out.c: BUG20511.  Modify persist timer to start when we are
+    prevented from sending by a small send window, not just a zero
+    send window.
+
+  2008-01-09 Jonathan Larmour
+  * opt.h, ip.c: Rename IP_OPTIONS define to IP_OPTIONS_ALLOWED to avoid
+    conflict with Linux system headers.
+
+  2008-01-06 Jonathan Larmour
+  * dhcp.c: fix bug #19927: "DHCP NACK problem" by clearing any existing set IP
+    address entirely on receiving a DHCPNAK, and restarting discovery.
+
+  2007-12-21 Simon Goldschmidt
+  * sys.h, api_lib.c, api_msg.c, sockets.c: fix bug #21698: "netconn->recv_avail
+    is not protected" by using new macros for interlocked access to modify/test
+    netconn->recv_avail.
+
+  2007-12-20 Kieran Mansley (based on patch from Oleg Tyshev)
+  * tcp_in.c: fix bug# 21535 (nrtx not reset correctly in SYN_SENT state)
+
+  2007-12-20 Kieran Mansley (based on patch from Per-Henrik Lundbolm)
+  * tcp.c, tcp_in.c, tcp_out.c, tcp.h: fix bug #20199 (better handling
+    of silly window avoidance and prevent lwIP from shrinking the window)
+
+  2007-12-04 Simon Goldschmidt
+  * tcp.c, tcp_in.c: fix bug #21699 (segment leak in ooseq processing when last
+    data packet was lost): add assert that all segment lists are empty in
+    tcp_pcb_remove before setting pcb to CLOSED state; don't directly set CLOSED
+    state from LAST_ACK in tcp_process
+
+  2007-12-02 Simon Goldschmidt
+  * sockets.h: fix bug #21654: exclude definition of struct timeval from #ifndef FD_SET
+    If including <sys/time.h> for system-struct timeval, LWIP_TIMEVAL_PRIVATE now
+    has to be set to 0 in lwipopts.h
+
+  2007-12-02 Simon Goldschmidt
+  * api_msg.c, api_lib.c: fix bug #21656 (recvmbox problem in netconn API): always
+    allocate a recvmbox in netconn_new_with_proto_and_callback. For a tcp-listen
+    netconn, this recvmbox is later freed and a new mbox is allocated for acceptmbox.
+    This is a fix for thread-safety and allocates all items needed for a netconn
+    when the netconn is created.
+
+  2007-11-30 Simon Goldschmidt
+  * udp.c: first attempt to fix bug #21655 (DHCP doesn't work reliably with multiple
+    netifs): if LWIP_DHCP is enabled, UDP packets to DHCP_CLIENT_PORT are passed
+    to netif->dhcp->pcb only (if that exists) and not to any other pcb for the same
+    port (only solution to let UDP pcbs 'bind' to a netif instead of an IP address)
+
+  2007-11-27 Simon Goldschmidt
+  * ip.c: fixed bug #21643 (udp_send/raw_send don't fail if netif is down) by
+    letting ip_route only use netifs that are up.
+
+  2007-11-27 Simon Goldschmidt
+  * err.h, api_lib.c, api_msg.c, sockets.c: Changed error handling: ERR_MEM, ERR_BUF
+    and ERR_RTE are seen as non-fatal, all other errors are fatal. netconns and
+    sockets block most operations once they have seen a fatal error.
+
+  2007-11-27 Simon Goldschmidt
+  * udp.h, udp.c, dhcp.c: Implemented new function udp_sendto_if which takes the
+    netif to send as an argument (to be able to send on netifs that are down).
+
+  2007-11-26 Simon Goldschmidt
+  * tcp_in.c: Fixed bug #21582: pcb->acked accounting can be wrong when ACKs
+    arrive out-of-order
+
+  2007-11-21 Simon Goldschmidt
+  * tcp.h, tcp_out.c, api_msg.c: Fixed bug #20287: tcp_output_nagle sends too early
+    Fixed the nagle algorithm; nagle now also works for all raw API applications
+    and has to be explicitly disabled with 'tcp_pcb->flags |= TF_NODELAY'
+
+  2007-11-12 Frédéric Bernon
+  * sockets.c, api.h, api_lib.c, api_msg.h, api_msg.c: Fixed bug #20900. Now, most
+    of the netconn_peer and netconn_addr processing is done inside tcpip_thread
+    context in do_getaddr.
+
+  2007-11-10 Simon Goldschmidt
+  * etharp.c: Fixed bug: assert fired when MEMP_ARP_QUEUE was empty (which can
+    happen any time). Now the packet simply isn't enqueued when out of memory.
+
+  2007-11-01 Simon Goldschmidt
+  * tcp.c, tcp_in.c: Fixed bug #21494: The send mss (pcb->mss) is set to 536 (or
+    TCP_MSS if that is smaller) as long as no MSS option is received from the
+    remote host.
+
+  2007-11-01 Simon Goldschmidt
+  * tcp.h, tcp.c, tcp_in.c: Fixed bug #21491: The MSS option sent (with SYN)
+    is now based on TCP_MSS instead of pcb->mss (on passive open now effectively
+    sending our configured TCP_MSS instead of the one received).
+
+  2007-11-01 Simon Goldschmidt
+  * tcp_in.c: Fixed bug #21181: On active open, the initial congestion window was
+    calculated based on the configured TCP_MSS, not on the MSS option received
+    with SYN+ACK.
+
+  2007-10-09 Simon Goldschmidt
+  * udp.c, inet.c, inet.h: Fixed UDPLite: send: Checksum was always generated too
+    short and also was generated wrong if checksum coverage != tot_len;
+    receive: checksum was calculated wrong if checksum coverage != tot_len
+
+  2007-10-08 Simon Goldschmidt
+  * mem.c: lfree was not updated in mem_realloc!
+
+  2007-10-07 Frédéric Bernon
+  * sockets.c, api.h, api_lib.c: First step to fix "bug #20900 : Potential
+    crash error problem with netconn_peer & netconn_addr". VERY IMPORTANT:
+    this change cause an API breakage for netconn_addr, since a parameter
+    type change. Any compiler should cause an error without any changes in
+    yours netconn_peer calls (so, it can't be a "silent change"). It also
+    reduce a little bit the footprint for socket layer (lwip_getpeername &
+    lwip_getsockname use now a common lwip_getaddrname function since 
+    netconn_peer & netconn_addr have the same parameters).
+
+  2007-09-20 Simon Goldschmidt
+  * tcp.c: Fixed bug #21080 (tcp_bind without check pcbs in TIME_WAIT state)
+    by checking  tcp_tw_pcbs also
+
+  2007-09-19 Simon Goldschmidt
+  * icmp.c: Fixed bug #21107 (didn't reset IP TTL in ICMP echo replies)
+
+  2007-09-15 Mike Kleshov
+  * mem.c: Fixed bug #21077 (inaccuracy in calculation of lwip_stat.mem.used)
+
+  2007-09-06 Frédéric Bernon
+  * several-files: replace some #include "arch/cc.h" by "lwip/arch.h", or simply remove
+    it as long as "lwip/opt.h" is included before (this one include "lwip/debug.h" which
+    already include "lwip/arch.h"). Like that, default defines are provided by "lwip/arch.h"
+    if they are not defined in cc.h, in the same spirit than "lwip/opt.h" for lwipopts.h.
+
+  2007-08-30 Frédéric Bernon
+  * igmp.h, igmp.c: Some changes to remove some redundant code, add some traces, 
+    and fix some coding style.
+
+  2007-08-28 Frédéric Bernon
+  * tcpip.c: Fix TCPIP_MSG_INPKT processing: now, tcpip_input can be used for any
+    kind of packets. These packets are considered like Ethernet packets (payload 
+    pointing to ethhdr) if the netif got the NETIF_FLAG_ETHARP flag. Else, packets 
+    are considered like IP packets (payload pointing to iphdr).
+
+  2007-08-27 Frédéric Bernon
+  * api.h, api_lib.c, api_msg.c: First fix for "bug #20900 : Potential crash error
+    problem with netconn_peer & netconn_addr". Introduce NETCONN_LISTEN netconn_state
+    and remove obsolete ones (NETCONN_RECV & NETCONN_ACCEPT).
+
+  2007-08-24 Kieran Mansley
+  * inet.c Modify (acc >> 16) test to ((acc >> 16) != 0) to help buggy
+    compiler (Paradigm C++)
+
+  2007-08-09 Frédéric Bernon, Bill Florac
+  * stats.h, stats.c, igmp.h, igmp.c, opt.h: Fix for bug #20503 : IGMP Improvement.
+    Introduce IGMP_STATS to centralize statistics management.
+
+  2007-08-09 Frédéric Bernon, Bill Florac
+  * udp.c: Fix for bug #20503 : IGMP Improvement. Enable to receive a multicast
+    packet on a udp pcb binded on an netif's IP address, and not on "any".
+
+  2007-08-09 Frédéric Bernon, Bill Florac
+  * igmp.h, igmp.c, ip.c: Fix minor changes from bug #20503 : IGMP Improvement.
+    This is mainly on using lookup/lookfor, and some coding styles...
+
+  2007-07-26 Frédéric Bernon (and "thedoctor")
+  * igmp.c: Fix bug #20595 to accept IGMPv3 "Query" messages.
+
+  2007-07-25 Simon Goldschmidt
+  * api_msg.c, tcp.c: Another fix for bug #20021: by not returning an error if
+    tcp_output fails in tcp_close, the code in do_close_internal gets simpler
+    (tcp_output is called again later from tcp timers).
+
+  2007-07-25 Simon Goldschmidt
+  * ip_frag.c: Fixed bug #20429: use the new pbuf_copy_partial instead of the old
+    copy_from_pbuf, which illegally modified the given pbuf.
+
+  2007-07-25 Simon Goldschmidt
+  * tcp_out.c: tcp_enqueue: pcb->snd_queuelen didn't work for chaine PBUF_RAMs:
+    changed snd_queuelen++ to snd_queuelen += pbuf_clen(p).
+
+  2007-07-24 Simon Goldschmidt
+  * api_msg.c, tcp.c: Fix bug #20480: Check the pcb passed to tcp_listen() for the
+    correct state (must be CLOSED).
+
+  2007-07-13 Thomas Taranowski (commited by Jared Grubb)
+  * memp.c: Fix bug #20478: memp_malloc returned NULL+MEMP_SIZE on failed
+    allocation. It now returns NULL.
+
+  2007-07-13 Frédéric Bernon
+  * api_msg.c: Fix bug #20318: api_msg "recv" callbacks don't call pbuf_free in
+    all error cases.
+
+  2007-07-13 Frédéric Bernon
+  * api_msg.c: Fix bug #20315: possible memory leak problem if tcp_listen failed,
+    because current code doesn't follow rawapi.txt documentation.
+
+  2007-07-13 Kieran Mansley
+  * src/core/tcp_in.c Apply patch#5741 from Oleg Tyshev to fix bug in
+    out of sequence processing of received packets
+
+  2007-07-03 Simon Goldschmidt
+  * nearly-all-files: Added assertions where PBUF_RAM pbufs are used and an
+    assumption is made that this pbuf is in one piece (i.e. not chained). These
+    assumptions clash with the possibility of converting to fully pool-based
+    pbuf implementations, where PBUF_RAM pbufs might be chained.
+
+  2007-07-03 Simon Goldschmidt
+  * api.h, api_lib.c, api_msg.c: Final fix for bug #20021 and some other problems
+    when closing tcp netconns: removed conn->sem, less context switches when
+    closing, both netconn_close and netconn_delete should safely close tcp
+    connections.
+
+  2007-07-02 Simon Goldschmidt
+  * ipv4/ip.h, ipv6/ip.h, opt.h, netif.h, etharp.h, ipv4/ip.c, netif.c, raw.c,
+    tcp_out.c, udp.c, etharp.c: Added option LWIP_NETIF_HWADDRHINT (default=off)
+    to cache ARP table indices with each pcb instead of single-entry cache for
+    the complete stack.
+
+  2007-07-02 Simon Goldschmidt
+  * tcp.h, tcp.c, tcp_in.c, tcp_out.c: Added some ASSERTS and casts to prevent
+    warnings when assigning to smaller types.
+
+  2007-06-28 Simon Goldschmidt
+  * tcp_out.c: Added check to prevent tcp_pcb->snd_queuelen from overflowing.
+
+  2007-06-28 Simon Goldschmidt
+  * tcp.h: Fixed bug #20287: Fixed nagle algorithm (sending was done too early if
+    a segment contained chained pbufs)
+
+  2007-06-28 Frédéric Bernon
+  * autoip.c: replace most of rand() calls by a macro LWIP_AUTOIP_RAND which compute
+    a "pseudo-random" value based on netif's MAC and some autoip fields. It's always
+    possible to define this macro in your own lwipopts.h to always use C library's
+    rand(). Note that autoip_create_rand_addr doesn't use this macro.
+
+  2007-06-28 Frédéric Bernon
+  * netifapi.h, netifapi.c, tcpip.h, tcpip.c: Update code to handle the option
+    LWIP_TCPIP_CORE_LOCKING, and do some changes to be coherent with last modifications
+    in api_lib/api_msg (use pointers and not type with table, etc...) 
+
+  2007-06-26 Simon Goldschmidt
+  * udp.h: Fixed bug #20259: struct udp_hdr was lacking the packin defines.
+
+  2007-06-25 Simon Goldschmidt
+  * udp.c: Fixed bug #20253: icmp_dest_unreach was called with a wrong p->payload
+    for udp packets with no matching pcb.
+
+  2007-06-25 Simon Goldschmidt
+  * udp.c: Fixed bug #20220: UDP PCB search in udp_input(): a non-local match
+    could get udp input packets if the remote side matched.
+
+  2007-06-13 Simon Goldschmidt
+  * netif.c: Fixed bug #20180 (TCP pcbs listening on IP_ADDR_ANY could get
+    changed in netif_set_ipaddr if previous netif->ip_addr.addr was 0.
+
+  2007-06-13 Simon Goldschmidt
+  * api_msg.c: pcb_new sets conn->err if protocol is not implemented
+    -> netconn_new_..() does not allocate a new connection for unsupported
+    protocols.
+
+  2007-06-13 Frédéric Bernon, Simon Goldschmidt
+  * api_lib.c: change return expression in netconn_addr and netconn_peer, because
+    conn->err was reset to ERR_OK without any reasons (and error was lost)...
+
+  2007-06-13 Frédéric Bernon, Matthias Weisser
+  * opt.h, mem.h, mem.c, memp.c, pbuf.c, ip_frag.c, vj.c: Fix bug #20162. Rename
+    MEM_ALIGN in LWIP_MEM_ALIGN and MEM_ALIGN_SIZE in LWIP_MEM_ALIGN_SIZE to avoid
+    some macro names collision with some OS macros.
+
+  2007-06-11 Simon Goldschmidt
+  * udp.c: UDP Lite: corrected the use of chksum_len (based on RFC3828: if it's 0,
+    create checksum over the complete packet. On RX, if it's < 8 (and not 0),
+    discard the packet. Also removed the duplicate 'udphdr->chksum = 0' for both
+    UDP & UDP Lite.
+
+  2007-06-11 Srinivas Gollakota & Oleg Tyshev
+  * tcp_out.c: Fix for bug #20075 : "A problem with keep-alive timer and TCP flags"
+    where TCP flags wasn't initialized in tcp_keepalive.
+
+  2007-06-03 Simon Goldschmidt
+  * udp.c: udp_input(): Input pbuf was not freed if pcb had no recv function
+    registered, p->payload was modified without modifying p->len if sending
+    icmp_dest_unreach() (had no negative effect but was definitively wrong).
+
+  2007-06-03 Simon Goldschmidt
+  * icmp.c: Corrected bug #19937: For responding to an icmp echo request, icmp
+    re-used the input pbuf even if that didn't have enough space to include the
+    link headers. Now the space is tested and a new pbuf is allocated for the
+    echo response packet if the echo request pbuf isn't big enough.
+
+  2007-06-01 Simon Goldschmidt
+  * sockets.c: Checked in patch #5914: Moved sockopt processing into tcpip_thread.
+
+  2007-05-23 Frédéric Bernon
+  * api_lib.c, sockets.c: Fixed bug #5958 for netconn_listen (acceptmbox only
+    allocated by do_listen if success) and netconn_accept errors handling. In
+    most of api_lib functions, we replace some errors checkings like "if (conn==NULL)"
+    by ASSERT, except for netconn_delete.
+
+  2007-05-23 Frédéric Bernon
+  * api_lib.c: Fixed bug #5957 "Safe-thread problem inside netconn_recv" to return
+    an error code if it's impossible to fetch a pbuf on a TCP connection (and not
+    directly close the recvmbox).
+
+  2007-05-22 Simon Goldschmidt
+  * tcp.c: Fixed bug #1895 (tcp_bind not correct) by introducing a list of
+    bound but unconnected (and non-listening) tcp_pcbs.
+
+  2007-05-22 Frédéric Bernon
+  * sys.h, sys.c, api_lib.c, tcpip.c: remove sys_mbox_fetch_timeout() (was only
+    used for LWIP_SO_RCVTIMEO option) and use sys_arch_mbox_fetch() instead of
+    sys_mbox_fetch() in api files. Now, users SHOULD NOT use internal lwIP features
+    like "sys_timeout" in their application threads.
+
+  2007-05-22 Frédéric Bernon
+  * api.h, api_lib.c, api_msg.h, api_msg.c: change the struct api_msg_msg to see
+    which parameters are used by which do_xxx function, and to avoid "misusing"
+    parameters (patch #5938).
+
+  2007-05-22 Simon Goldschmidt
+  * api_lib.c, api_msg.c, raw.c, api.h, api_msg.h, raw.h: Included patch #5938:
+    changed raw_pcb.protocol from u16_t to u8_t since for IPv4 and IPv6, proto
+    is only 8 bits wide. This affects the api, as there, the protocol was
+    u16_t, too.
+
+  2007-05-18 Simon Goldschmidt
+  * memp.c: addition to patch #5913: smaller pointer was returned but
+    memp_memory was the same size -> did not save memory.
+
+  2007-05-16 Simon Goldschmidt
+  * loopif.c, slipif.c: Fix bug #19729: free pbuf if netif->input() returns
+    != ERR_OK.
+
+  2007-05-16 Simon Goldschmidt
+  * api_msg.c, udp.c: If a udp_pcb has a local_ip set, check if it is the same
+    as the one of the netif used for sending to prevent sending from old
+    addresses after a netif address gets changed (partly fixes bug #3168).
+
+  2007-05-16 Frédéric Bernon
+  * tcpip.c, igmp.h, igmp.c: Fixed bug "#19800 : IGMP: igmp_tick() will not work
+    with NO_SYS=1". Note that igmp_init is always in tcpip_thread (and not in 
+    tcpip_init) because we have to be sure that network interfaces are already
+    added (mac filter is updated only in igmp_init for the moment).
+
+  2007-05-16 Simon Goldschmidt
+  * mem.c, memp.c: Removed semaphores from memp, changed sys_sem_wait calls
+    into sys_arch_sem_wait calls to prevent timers from running while waiting
+    for the heap. This fixes bug #19167.
+
+  2007-05-13 Simon Goldschmidt
+  * tcp.h, sockets.h, sockets.c: Fixed bug from patch #5865 by moving the defines
+    for socket options (lwip_set/-getsockopt) used with level IPPROTO_TCP from
+    tcp.h to sockets.h.
+
+  2007-05-07 Simon Goldschmidt
+  * mem.c: Another attempt to fix bug #17922.
+
+  2007-05-04 Simon Goldschmidt
+  * pbuf.c, pbuf.h, etharp.c: Further update to ARP queueing: Changed pbuf_copy()
+    implementation so that it can be reused (don't allocate the target
+    pbuf inside pbuf_copy()).
+
+  2007-05-04 Simon Goldschmidt
+  * memp.c: checked in patch #5913: in memp_malloc() we can return memp as mem
+    to save a little RAM (next pointer of memp is not used while not in pool).
+
+  2007-05-03 "maq"
+  * sockets.c: Fix ioctl FIONREAD when some data remains from last recv.
+    (patch #3574).
+
+  2007-04-23 Simon Goldschmidt
+  * loopif.c, loopif.h, opt.h, src/netif/FILES: fix bug #2595: "loopif results
+    in NULL reference for incoming TCP packets". Loopif has to be configured
+    (using LWIP_LOOPIF_MULTITHREADING) to directly call netif->input()
+    (multithreading environments, e.g. netif->input() = tcpip_input()) or
+    putting packets on a list that is fed to the stack by calling loopif_poll()
+    (single-thread / NO_SYS / polling environment where e.g.
+    netif->input() = ip_input).
+
+  2007-04-17 Jonathan Larmour
+  * pbuf.c: Use s32_t in pbuf_realloc(), as an s16_t can't reliably hold
+    the difference between two u16_t's.
+  * sockets.h: FD_SETSIZE needs to match number of sockets, which is
+    MEMP_NUM_NETCONN in sockets.c right now.
+
+  2007-04-12 Jonathan Larmour
+  * icmp.c: Reset IP header TTL in ICMP ECHO responses (bug #19580).
+
+  2007-04-12 Kieran Mansley
+  * tcp.c, tcp_in.c, tcp_out.c, tcp.h: Modify way the retransmission
+    timer is reset to fix bug#19434, with help from Oleg Tyshev.
+
+  2007-04-11 Simon Goldschmidt
+  * etharp.c, pbuf.c, pbuf.h: 3rd fix for bug #11400 (arp-queuing): More pbufs than
+    previously thought need to be copied (everything but PBUF_ROM!). Cleaned up
+    pbuf.c: removed functions no needed any more (by etharp).
+
+  2007-04-11 Kieran Mansley
+  * inet.c, ip_addr.h, sockets.h, sys.h, tcp.h: Apply patch #5745: Fix
+    "Constant is long" warnings with 16bit compilers.  Contributed by
+    avatar@mmlab.cse.yzu.edu.tw
+
+  2007-04-05 Frédéric Bernon, Jonathan Larmour
+  * api_msg.c: Fix bug #16830: "err_tcp() posts to connection mailbox when no pend on
+    the mailbox is active". Now, the post is only done during a connect, and do_send,
+    do_write and do_join_leave_group don't do anything if a previous error was signaled.
+
+  2007-04-03 Frédéric Bernon
+  * ip.c: Don't set the IP_DF ("Don't fragment") flag in the IP header in IP output
+    packets. See patch #5834.
+
+  2007-03-30 Frédéric Bernon
+  * api_msg.c: add a "pcb_new" helper function to avoid redundant code, and to add
+    missing  pcb allocations checking (in do_bind, and for each raw_new). Fix style.
+
+  2007-03-30 Frédéric Bernon
+  * most of files: prefix all debug.h define with "LWIP_" to avoid any conflict with
+    others environment defines (these were too "generic").
+
+  2007-03-28 Frédéric Bernon
+  * api.h, api_lib.c, sockets.c: netbuf_ref doesn't check its internal pbuf_alloc call
+    result and can cause a crash. lwip_send now check netbuf_ref result.
+
+  2007-03-28 Simon Goldschmidt
+  * sockets.c Remove "#include <errno.h>" from sockets.c to avoid multiple
+    definition of macros (in errno.h and lwip/arch.h) if LWIP_PROVIDE_ERRNO is
+    defined. This is the way it should have been already (looking at
+    doc/sys_arch.txt)
+
+  2007-03-28 Kieran Mansley
+  * opt.h Change default PBUF_POOL_BUFSIZE (again) to accomodate default MSS +
+    IP and TCP headers *and* physical link headers
+
+  2007-03-26 Frédéric Bernon (based on patch from Dmitry Potapov)
+  * api_lib.c: patch for netconn_write(), fixes a possible race condition which cause
+    to send some garbage. It is not a definitive solution, but the patch does solve
+    the problem for most cases.
+
+  2007-03-22 Frédéric Bernon
+  * api_msg.h, api_msg.c: Remove obsolete API_MSG_ACCEPT and do_accept (never used).
+
+  2007-03-22 Frédéric Bernon
+  * api_lib.c: somes resources couldn't be freed if there was errors during
+    netconn_new_with_proto_and_callback.
+
+  2007-03-22 Frédéric Bernon
+  * ethernetif.c: update netif->input calls to check return value. In older ports,
+    it's a good idea to upgrade them, even if before, there could be another problem
+    (access to an uninitialized mailbox).
+
+  2007-03-21 Simon Goldschmidt
+  * sockets.c: fixed bug #5067 (essentialy a signed/unsigned warning fixed
+    by casting to unsigned).
+
+  2007-03-21 Frédéric Bernon
+  * api_lib.c, api_msg.c, tcpip.c: integrate sys_mbox_fetch(conn->mbox, NULL) calls from
+    api_lib.c to tcpip.c's tcpip_apimsg(). Now, use a local variable and not a
+    dynamic one from memp to send tcpip_msg to tcpip_thread in a synchrone call.
+    Free tcpip_msg from tcpip_apimsg is not done in tcpip_thread. This give a
+    faster and more reliable communication between api_lib and tcpip.
+
+  2007-03-21 Frédéric Bernon
+  * opt.h: Add LWIP_NETIF_CALLBACK (to avoid compiler warning) and set it to 0.
+
+  2007-03-21 Frédéric Bernon
+  * api_msg.c, igmp.c, igmp.h: Fix C++ style comments
+
+  2007-03-21 Kieran Mansley
+  * opt.h Change default PBUF_POOL_BUFSIZE to accomodate default MSS +
+    IP and TCP headers
+
+  2007-03-21 Kieran Mansley
+  * Fix all uses of pbuf_header to check the return value.  In some
+    cases just assert if it fails as I'm not sure how to fix them, but
+    this is no worse than before when they would carry on regardless
+    of the failure.
+
+  2007-03-21 Kieran Mansley
+  * sockets.c, igmp.c, igmp.h, memp.h: Fix C++ style comments and
+    comment out missing header include in icmp.c
+
+  2007-03-20 Frédéric Bernon
+  * memp.h, stats.c: Fix stats_display function where memp_names table wasn't
+    synchronized with memp.h.
+
+  2007-03-20 Frédéric Bernon
+  * tcpip.c: Initialize tcpip's mbox, and verify if initialized in tcpip_input,
+    tcpip_ethinput, tcpip_callback, tcpip_apimsg, to fix a init problem with 
+    network interfaces. Also fix a compiler warning.
+
+  2007-03-20 Kieran Mansley
+  * udp.c: Only try and use pbuf_header() to make space for headers if
+    not a ROM or REF pbuf.
+
+  2007-03-19 Frédéric Bernon
+  * api_msg.h, api_msg.c, tcpip.h, tcpip.c: Add return types to tcpip_apimsg()
+    and api_msg_post().
+
+  2007-03-19 Frédéric Bernon
+  * Remove unimplemented "memp_realloc" function from memp.h.
+
+  2007-03-11 Simon Goldschmidt
+  * pbuf.c: checked in patch #5796: pbuf_alloc: len field claculation caused
+    memory corruption.
+
+  2007-03-11 Simon Goldschmidt (based on patch from Dmitry Potapov)
+  * api_lib.c, sockets.c, api.h, api_msg.h, sockets.h: Fixed bug #19251
+    (missing `const' qualifier in socket functions), to get more compatible to
+    standard POSIX sockets.
+
+  2007-03-11 Frédéric Bernon (based on patch from Dmitry Potapov)
+  * sockets.c: Add asserts inside bind, connect and sendto to check input
+    parameters. Remove excessive set_errno() calls after get_socket(), because
+    errno is set inside of get_socket(). Move last sock_set_errno() inside
+    lwip_close.
+
+  2007-03-09 Simon Goldschmidt
+  * memp.c: Fixed bug #11400: New etharp queueing introduced bug: memp_memory
+    was allocated too small.
+
+  2007-03-06 Simon Goldschmidt
+  * tcpip.c: Initialize dhcp timers in tcpip_thread (if LWIP_DHCP) to protect
+    the stack from concurrent access.
+
+  2007-03-06 Frédéric Bernon, Dmitry Potapov
+  * tcpip.c, ip_frag.c, ethernetif.c: Fix some build problems, and a redundancy
+    call to "lwip_stats.link.recv++;" in low_level_input() & ethernetif_input().
+
+  2007-03-06 Simon Goldschmidt
+  * ip_frag.c, ip_frag.h: Reduce code size: don't include code in those files
+    if IP_FRAG == 0 and IP_REASSEMBLY == 0
+
+  2007-03-06 Frédéric Bernon, Simon Goldschmidt
+  * opt.h, ip_frag.h, tcpip.h, tcpip.c, ethernetif.c: add new configuration
+    option named ETHARP_TCPIP_ETHINPUT, which enable the new tcpip_ethinput.
+    Allow to do ARP processing for incoming packets inside tcpip_thread
+    (protecting ARP layer against concurrent access). You can also disable
+    old code using tcp_input with new define ETHARP_TCPIP_INPUT set to 0.
+    Older ports have to use tcpip_ethinput.
+
+  2007-03-06 Simon Goldschmidt (based on patch from Dmitry Potapov)
+  * err.h, err.c: fixed compiler warning "initialization dircards qualifiers
+    from pointer target type"
+
+  2007-03-05 Frédéric Bernon
+  * opt.h, sockets.h: add new configuration options (LWIP_POSIX_SOCKETS_IO_NAMES,
+    ETHARP_TRUST_IP_MAC, review SO_REUSE)
+
+  2007-03-04 Frédéric Bernon
+  * api_msg.c: Remove some compiler warnings : parameter "pcb" was never
+    referenced.
+
+  2007-03-04 Frédéric Bernon
+  * api_lib.c: Fix "[patch #5764] api_lib.c cleanup: after patch #5687" (from
+    Dmitry Potapov).
+    The api_msg struct stay on the stack (not moved to netconn struct).
+
+  2007-03-04 Simon Goldschmidt (based on patch from Dmitry Potapov)
+  * pbuf.c: Fix BUG#19168 - pbuf_free can cause deadlock (if
+    SYS_LIGHTWEIGHT_PROT=1 & freeing PBUF_RAM when mem_sem is not available)
+    Also fixed cast warning in pbuf_alloc()
+
+  2007-03-04 Simon Goldschmidt
+  * etharp.c, etharp.h, memp.c, memp.h, opt.h: Fix BUG#11400 - don't corrupt
+    existing pbuf chain when enqueuing multiple pbufs to a pending ARP request
+
+  2007-03-03 Frédéric Bernon
+  * udp.c: remove obsolete line "static struct udp_pcb *pcb_cache = NULL;"
+    It is static, and never used in udp.c except udp_init().
+
+  2007-03-02 Simon Goldschmidt
+  * tcpip.c: Moved call to ip_init(), udp_init() and tcp_init() from
+    tcpip_thread() to tcpip_init(). This way, raw API connections can be
+    initialized before tcpip_thread is running (e.g. before OS is started)
+
+  2007-03-02 Frédéric Bernon
+  * rawapi.txt: Fix documentation mismatch with etharp.h about etharp_tmr's call
+    interval.
+
+  2007-02-28 Kieran Mansley 
+  * pbuf.c: Fix BUG#17645 - ensure pbuf payload pointer is not moved
+    outside the region of the pbuf by pbuf_header()
+
+  2007-02-28 Kieran Mansley 
+  * sockets.c: Fix BUG#19161 - ensure milliseconds timeout is non-zero
+    when supplied timeout is also non-zero 
+
+(STABLE-1.2.0)
+
+  2006-12-05 Leon Woestenberg
+  * CHANGELOG: Mention STABLE-1.2.0 release.
+
+  ++ New features:
+
+  2006-12-01 Christiaan Simons
+  * mem.h, opt.h: Added MEM_LIBC_MALLOC option.
+    Note this is a workaround. Currently I have no other options left.
+
+  2006-10-26 Christiaan Simons (accepted patch by Jonathan Larmour)
+  * ipv4/ip_frag.c: rename MAX_MTU to IP_FRAG_MAX_MTU and move define
+    to include/lwip/opt.h.
+  * ipv4/lwip/ip_frag.h: Remove unused IP_REASS_INTERVAL.
+    Move IP_REASS_MAXAGE and IP_REASS_BUFSIZE to include/lwip/opt.h.
+  * opt.h: Add above new options.
+
+  2006-08-18 Christiaan Simons
+  * tcp_{in,out}.c: added SNMP counters.
+  * ipv4/ip.c: added SNMP counters.
+  * ipv4/ip_frag.c: added SNMP counters.
+
+  2006-08-08 Christiaan Simons
+  * etharp.{c,h}: added etharp_find_addr() to read
+    (stable) ethernet/IP address pair from ARP table
+
+  2006-07-14 Christiaan Simons
+  * mib_structs.c: added
+  * include/lwip/snmp_structs.h: added
+  * netif.{c,h}, netif/ethernetif.c: added SNMP statistics to netif struct
+
+  2006-07-06 Christiaan Simons
+  * snmp/asn1_{enc,dec}.c added
+  * snmp/mib2.c added
+  * snmp/msg_{in,out}.c added
+  * include/lwip/snmp_asn1.h added
+  * include/lwip/snmp_msg.h added
+  * doc/snmp_agent.txt added
+
+  2006-03-29 Christiaan Simons
+  * inet.c, inet.h: Added platform byteswap support.
+    Added LWIP_PLATFORM_BYTESWAP define (defaults to 0) and
+    optional LWIP_PLATFORM_HTONS(), LWIP_PLATFORM_HTONL() macros.
+
+  ++ Bug fixes:
+
+  2006-11-30 Christiaan Simons
+  * dhcp.c: Fixed false triggers of request_timeout.
+
+  2006-11-28 Christiaan Simons
+  * netif.c: In netif_add() fixed missing clear of ip_addr, netmask, gw and flags.
+
+  2006-10-11 Christiaan Simons
+  * api_lib.c etharp.c, ip.c, memp.c, stats.c, sys.{c,h} tcp.h:
+    Partially accepted patch #5449 for ANSI C compatibility / build fixes.
+  * ipv4/lwip/ip.h ipv6/lwip/ip.h: Corrected UDP-Lite protocol
+    identifier from 170 to 136 (bug #17574).
+
+  2006-10-10 Christiaan Simons
+  * api_msg.c: Fixed Nagle algorithm as reported by Bob Grice.
+
+  2006-08-17 Christiaan Simons
+  * udp.c: Fixed bug #17200, added check for broadcast
+    destinations for PCBs bound to a unicast address.
+
+  2006-08-07 Christiaan Simons
+  * api_msg.c: Flushing TCP output in do_close() (bug #15926).
+
+  2006-06-27 Christiaan Simons
+  * api_msg.c: Applied patch for cold case (bug #11135).
+    In accept_function() ensure newconn->callback is always initialized.
+
+  2006-06-15 Christiaan Simons
+  * mem.h: added MEM_SIZE_F alias to fix an ancient cold case (bug #1748),
+    facilitate printing of mem_size_t and u16_t statistics.
+
+  2006-06-14 Christiaan Simons
+  * api_msg.c: Applied patch #5146 to handle allocation failures
+    in accept() by Kevin Lawson.
+
+  2006-05-26 Christiaan Simons
+  * api_lib.c: Removed conn->sem creation and destruction 
+    from netconn_write() and added sys_sem_new to netconn_new_*.
+
+(STABLE-1_1_1)
+
+  2006-03-03  Christiaan Simons
+  * ipv4/ip_frag.c: Added bound-checking assertions on ip_reassbitmap
+    access and added pbuf_alloc() return value checks.
+
+  2006-01-01  Leon Woestenberg <leon.woestenberg@gmx.net>
+  * tcp_{in,out}.c, tcp_out.c: Removed 'even sndbuf' fix in TCP, which is
+    now handled by the checksum routine properly.
+
+  2006-02-27  Leon Woestenberg <leon.woestenberg@gmx.net>
+   * pbuf.c: Fix alignment; pbuf_init() would not work unless
+     pbuf_pool_memory[] was properly aligned. (Patch by Curt McDowell.)
+
+  2005-12-20  Leon Woestenberg <leon.woestenberg@gmx.net>
+  * tcp.c: Remove PCBs which stay in LAST_ACK state too long. Patch
+    submitted by Mitrani Hiroshi.
+
+  2005-12-15  Christiaan Simons
+  * inet.c: Disabled the added summing routine to preserve code space.
+
+  2005-12-14  Leon Woestenberg <leon.woestenberg@gmx.net>
+  * tcp_in.c: Duplicate FIN ACK race condition fix by Kelvin Lawson.
+    Added Curt McDowell's optimized checksumming routine for future
+    inclusion. Need to create test case for unaliged, aligned, odd,
+    even length combination of cases on various endianess machines.
+
+  2005-12-09  Christiaan Simons
+  * inet.c: Rewrote standard checksum routine in proper portable C.
+
+  2005-11-25  Christiaan Simons
+  * udp.c tcp.c: Removed SO_REUSE hack. Should reside in socket code only.
+  * *.c: introduced cc.h LWIP_DEBUG formatters matching the u16_t, s16_t,
+    u32_t, s32_t typedefs. This solves most debug word-length assumes.
+
+  2005-07-17 Leon Woestenberg <leon.woestenberg@gmx.net>
+  * inet.c: Fixed unaligned 16-bit access in the standard checksum
+    routine by Peter Jolasson.
+  * slipif.c: Fixed implementation assumption of single-pbuf datagrams.
+
+  2005-02-04 Leon Woestenberg <leon.woestenberg@gmx.net>
+  * tcp_out.c: Fixed uninitialized 'queue' referenced in memerr branch.
+  * tcp_{out|in}.c: Applied patch fixing unaligned access.
+
+  2005-01-04 Leon Woestenberg <leon.woestenberg@gmx.net>
+  * pbuf.c: Fixed missing semicolon after LWIP_DEBUG statement.
+
+  2005-01-03 Leon Woestenberg <leon.woestenberg@gmx.net>
+  * udp.c: UDP pcb->recv() was called even when it was NULL.
+
+(STABLE-1_1_0)
+
+  2004-12-28 Leon Woestenberg <leon.woestenberg@gmx.net>
+  * etharp.*: Disabled multiple packets on the ARP queue.
+    This clashes with TCP queueing.
+
+  2004-11-28 Leon Woestenberg <leon.woestenberg@gmx.net>
+  * etharp.*: Fixed race condition from ARP request to ARP timeout.
+    Halved the ARP period, doubled the period counts.
+    ETHARP_MAX_PENDING now should be at least 2. This prevents
+    the counter from reaching 0 right away (which would allow
+    too little time for ARP responses to be received).
+
+  2004-11-25 Leon Woestenberg <leon.woestenberg@gmx.net>
+  * dhcp.c: Decline messages were not multicast but unicast.
+  * etharp.c: ETHARP_CREATE is renamed to ETHARP_TRY_HARD.
+    Do not try hard to insert arbitrary packet's source address,
+    etharp_ip_input() now calls etharp_update() without ETHARP_TRY_HARD. 
+    etharp_query() now always DOES call ETHARP_TRY_HARD so that users
+    querying an address will see it appear in the cache (DHCP could
+    suffer from this when a server invalidly gave an in-use address.)
+  * ipv4/ip_addr.h: Renamed ip_addr_maskcmp() to _netcmp() as we are
+    comparing network addresses (identifiers), not the network masks
+    themselves.
+  * ipv4/ip_addr.c: ip_addr_isbroadcast() now checks that the given
+    IP address actually belongs to the network of the given interface.
+
+  2004-11-24 Kieran Mansley <kjm25@cam.ac.uk>
+  * tcp.c: Increment pcb->snd_buf when ACK is received in SYN_SENT state.
+
+(STABLE-1_1_0-RC1)
+
+  2004-10-16 Kieran Mansley <kjm25@cam.ac.uk>
+  * tcp.c: Add code to tcp_recved() to send an ACK (window update) immediately,
+    even if one is already pending, if the rcv_wnd is above a threshold
+    (currently TCP_WND/2). This avoids waiting for a timer to expire to send a
+    delayed ACK in order to open the window if the stack is only receiving data.
+
+  2004-09-12 Kieran Mansley <kjm25@cam.ac.uk>
+  * tcp*.*: Retransmit time-out handling improvement by Sam Jansen.
+
+  2004-08-20 Tony Mountifield <tony@softins.co.uk>
+  * etharp.c: Make sure the first pbuf queued on an ARP entry
+    is properly ref counted.
+
+  2004-07-27 Tony Mountifield <tony@softins.co.uk>
+  * debug.h: Added (int) cast in LWIP_DEBUGF() to avoid compiler
+    warnings about comparison.
+  * pbuf.c: Stopped compiler complaining of empty if statement
+    when LWIP_DEBUGF() empty.  Closed an unclosed comment.
+  * tcp.c: Stopped compiler complaining of empty if statement
+    when LWIP_DEBUGF() empty.
+  * ip.h Corrected IPH_TOS() macro: returns a byte, so doesn't need htons().
+  * inet.c: Added a couple of casts to quiet the compiler.
+    No need to test isascii(c) before isdigit(c) or isxdigit(c).
+
+  2004-07-22 Tony Mountifield <tony@softins.co.uk>
+  * inet.c: Made data types consistent in inet_ntoa().
+    Added casts for return values of checksum routines, to pacify compiler.
+  * ip_frag.c, tcp_out.c, sockets.c, pbuf.c
+    Small corrections to some debugging statements, to pacify compiler.
+
+  2004-07-21 Tony Mountifield <tony@softins.co.uk>
+  * etharp.c: Removed spurious semicolon and added missing end-of-comment.
+  * ethernetif.c Updated low_level_output() to match prototype for
+    netif->linkoutput and changed low_level_input() similarly for consistency.
+  * api_msg.c: Changed recv_raw() from int to u8_t, to match prototype
+    of raw_recv() in raw.h and so avoid compiler error.
+  * sockets.c: Added trivial (int) cast to keep compiler happier.
+  * ip.c, netif.c Changed debug statements to use the tidier ip4_addrN() macros.
+
+(STABLE-1_0_0)
+
+  ++ Changes:
+
+  2004-07-05 Leon Woestenberg <leon.woestenberg@gmx.net>
+  * sockets.*: Restructured LWIP_PRIVATE_TIMEVAL. Make sure
+    your cc.h file defines this either 1 or 0. If non-defined,
+    defaults to 1.
+  * .c: Added <string.h> and <errno.h> includes where used.
+  * etharp.c: Made some array indices unsigned.
+
+  2004-06-27 Leon Woestenberg <leon.woestenberg@gmx.net>
+  * netif.*: Added netif_set_up()/down().
+  * dhcp.c: Changes to restart program flow.
+
+  2004-05-07 Leon Woestenberg <leon.woestenberg@gmx.net>
+  * etharp.c: In find_entry(), instead of a list traversal per candidate, do a
+    single-pass lookup for different candidates. Should exploit locality.
+
+  2004-04-29 Leon Woestenberg <leon.woestenberg@gmx.net>
+  * tcp*.c: Cleaned up source comment documentation for Doxygen processing.
+  * opt.h: ETHARP_ALWAYS_INSERT option removed to comply with ARP RFC.
+  * etharp.c: update_arp_entry() only adds new ARP entries when adviced to by
+    the caller. This deprecates the ETHARP_ALWAYS_INSERT overrule option.
+
+  ++ Bug fixes:
+
+  2004-04-27 Leon Woestenberg <leon.woestenberg@gmx.net>
+  * etharp.c: Applied patch of bug #8708 by Toni Mountifield with a solution
+    suggested by Timmy Brolin. Fix for 32-bit processors that cannot access
+    non-aligned 32-bit words, such as soms 32-bit TCP/IP header fields. Fix
+    is to prefix the 14-bit Ethernet headers with two padding bytes.
+
+  2004-04-23 Leon Woestenberg <leon.woestenberg@gmx.net>
+  * ip_addr.c: Fix in the ip_addr_isbroadcast() check.
+  * etharp.c: Fixed the case where the packet that initiates the ARP request
+    is not queued, and gets lost. Fixed the case where the packets destination
+    address is already known; we now always queue the packet and perform an ARP
+    request.
+
+(STABLE-0_7_0)
+
+  ++ Bug fixes:
+
+  * Fixed TCP bug for SYN_SENT to ESTABLISHED state transition.
+  * Fixed TCP bug in dequeueing of FIN from out of order segment queue.
+  * Fixed two possible NULL references in rare cases.
+
+(STABLE-0_6_6)
+
+  ++ Bug fixes:
+
+  * Fixed DHCP which did not include the IP address in DECLINE messages.
+
+  ++ Changes:
+
+  * etharp.c has been hauled over a bit.
+
+(STABLE-0_6_5)
+
+  ++ Bug fixes:
+
+  * Fixed TCP bug induced by bad window resizing with unidirectional TCP traffic.
+  * Packets sent from ARP queue had invalid source hardware address.
+
+  ++ Changes:
+
+  * Pass-by ARP requests do now update the cache.
+
+  ++ New features:
+
+  * No longer dependent on ctype.h.
+  * New socket options.
+  * Raw IP pcb support.
+
+(STABLE-0_6_4)
+
+  ++ Bug fixes:
+
+  * Some debug formatters and casts fixed.
+  * Numereous fixes in PPP.
+
+  ++ Changes:
+
+  * DEBUGF now is LWIP_DEBUGF
+  * pbuf_dechain() has been re-enabled.
+  * Mentioned the changed use of CVS branches in README.
+
+(STABLE-0_6_3)
+
+  ++ Bug fixes:
+
+  * Fixed pool pbuf memory leak in pbuf_alloc().
+    Occured if not enough PBUF_POOL pbufs for a packet pbuf chain.
+    Reported by Savin Zlobec.
+
+  * PBUF_POOL chains had their tot_len field not set for non-first
+    pbufs. Fixed in pbuf_alloc().
+
+  ++ New features:
+
+  * Added PPP stack contributed by Marc Boucher
+
+  ++ Changes:
+
+  * Now drops short packets for ICMP/UDP/TCP protocols. More robust.
+
+  * ARP queueuing now queues the latest packet instead of the first.
+    This is the RFC recommended behaviour, but can be overridden in
+    lwipopts.h.
+
+(0.6.2)
+
+  ++ Bugfixes:
+
+  * TCP has been fixed to deal with the new use of the pbuf->ref
+    counter.
+
+  * DHCP dhcp_inform() crash bug fixed.
+
+  ++ Changes:
+
+  * Removed pbuf_pool_free_cache and pbuf_pool_alloc_cache. Also removed
+    pbuf_refresh(). This has sped up pbuf pool operations considerably.
+    Implemented by David Haas.
+
+(0.6.1)
+
+  ++ New features:
+
+  * The packet buffer implementation has been enhanced to support
+    zero-copy and copy-on-demand for packet buffers which have their
+    payloads in application-managed memory.
+    Implemented by David Haas.
+
+    Use PBUF_REF to make a pbuf refer to RAM. lwIP will use zero-copy
+    if an outgoing packet can be directly sent on the link, or perform
+    a copy-on-demand when necessary.
+
+    The application can safely assume the packet is sent, and the RAM
+    is available to the application directly after calling udp_send()
+    or similar function.
+
+  ++ Bugfixes:
+
+  * ARP_QUEUEING should now correctly work for all cases, including
+    PBUF_REF.
+    Implemented by Leon Woestenberg.
+
+  ++ Changes:
+
+  * IP_ADDR_ANY is no longer a NULL pointer. Instead, it is a pointer
+    to a '0.0.0.0' IP address.
+
+  * The packet buffer implementation is changed. The pbuf->ref counter
+    meaning has changed, and several pbuf functions have been
+    adapted accordingly.
+
+  * netif drivers have to be changed to set the hardware address length field
+    that must be initialized correctly by the driver (hint: 6 for Ethernet MAC).
+    See the contrib/ports/c16x cs8900 driver as a driver example.
+
+  * netif's have a dhcp field that must be initialized to NULL by the driver.
+    See the contrib/ports/c16x cs8900 driver as a driver example.
+
+(0.5.x) This file has been unmaintained up to 0.6.1. All changes are
+  logged in CVS but have not been explained here.
+
+(0.5.3) Changes since version 0.5.2
+
+  ++ Bugfixes:
+
+  * memp_malloc(MEMP_API_MSG) could fail with multiple application
+    threads because it wasn't protected by semaphores.
+
+  ++ Other changes:
+
+  * struct ip_addr now packed.
+
+  * The name of the time variable in arp.c has been changed to ctime
+    to avoid conflicts with the time() function.
+
+(0.5.2) Changes since version 0.5.1
+
+  ++ New features:
+
+  * A new TCP function, tcp_tmr(), now handles both TCP timers.
+
+  ++ Bugfixes:
+
+  * A bug in tcp_parseopt() could cause the stack to hang because of a
+    malformed TCP option.
+
+  * The address of new connections in the accept() function in the BSD
+    socket library was not handled correctly.
+
+  * pbuf_dechain() did not update the ->tot_len field of the tail.
+
+  * Aborted TCP connections were not handled correctly in all
+    situations.
+
+  ++ Other changes:
+
+  * All protocol header structs are now packed.
+
+  * The ->len field in the tcp_seg structure now counts the actual
+    amount of data, and does not add one for SYN and FIN segments.
+
+(0.5.1) Changes since version 0.5.0
+
+  ++ New features:
+
+  * Possible to run as a user process under Linux.
+
+  * Preliminary support for cross platform packed structs.
+
+  * ARP timer now implemented.
+
+  ++ Bugfixes:
+
+  * TCP output queue length was badly initialized when opening
+    connections.
+
+  * TCP delayed ACKs were not sent correctly.
+
+  * Explicit initialization of BSS segment variables.
+
+  * read() in BSD socket library could drop data.
+
+  * Problems with memory alignment.
+
+  * Situations when all TCP buffers were used could lead to
+    starvation.
+
+  * TCP MSS option wasn't parsed correctly.
+
+  * Problems with UDP checksum calculation.
+
+  * IP multicast address tests had endianess problems.
+
+  * ARP requests had wrong destination hardware address.
+
+  ++ Other changes:
+
+  * struct eth_addr changed from u16_t[3] array to u8_t[6].
+
+  * A ->linkoutput() member was added to struct netif.
+
+  * TCP and UDP ->dest_* struct members where changed to ->remote_*.
+
+  * ntoh* macros are now null definitions for big endian CPUs.
+
+(0.5.0) Changes since version 0.4.2
+
+  ++ New features:
+
+  * Redesigned operating system emulation layer to make porting easier.
+
+  * Better control over TCP output buffers.
+
+  * Documenation added.
+
+  ++ Bugfixes:
+
+  * Locking issues in buffer management.
+
+  * Bugfixes in the sequential API.
+
+  * IP forwarding could cause memory leakage. This has been fixed.
+
+  ++ Other changes:
+
+  * Directory structure somewhat changed; the core/ tree has been
+    collapsed.
+
+(0.4.2) Changes since version 0.4.1
+
+  ++ New features:
+
+  * Experimental ARP implementation added.
+
+  * Skeleton Ethernet driver added.
+
+  * Experimental BSD socket API library added.
+
+  ++ Bugfixes:
+
+  * In very intense situations, memory leakage could occur. This has
+    been fixed.
+
+  ++ Other changes:
+
+  * Variables named "data" and "code" have been renamed in order to
+    avoid name conflicts in certain compilers.
+
+  * Variable++ have in appliciable cases been translated to ++variable
+    since some compilers generate better code in the latter case.
+
+(0.4.1) Changes since version 0.4
+
+  ++ New features:
+
+  * TCP: Connection attempts time out earlier than data
+    transmissions. Nagle algorithm implemented. Push flag set on the
+    last segment in a burst.
+
+  * UDP: experimental support for UDP-Lite extensions.
+
+  ++ Bugfixes:
+
+  * TCP: out of order segments were in some cases handled incorrectly,
+    and this has now been fixed. Delayed acknowledgements was broken
+    in 0.4, has now been fixed. Binding to an address that is in use
+    now results in an error. Reset connections sometimes hung an
+    application; this has been fixed.
+
+  * Checksum calculation sometimes failed for chained pbufs with odd
+    lengths. This has been fixed.
+
+  * API: a lot of bug fixes in the API. The UDP API has been improved
+    and tested. Error reporting and handling has been
+    improved. Logical flaws and race conditions for incoming TCP
+    connections has been found and removed.
+
+  * Memory manager: alignment issues. Reallocating memory sometimes
+    failed, this has been fixed.
+
+  * Generic library: bcopy was flawed and has been fixed.
+
+  ++ Other changes:
+
+  * API: all datatypes has been changed from generic ones such as
+    ints, to specified ones such as u16_t. Functions that return
+    errors now have the correct type (err_t).
+
+  * General: A lot of code cleaned up and debugging code removed. Many
+    portability issues have been fixed.
+
+  * The license was changed; the advertising clause was removed.
+
+  * C64 port added.
+
+  * Thanks: Huge thanks go to Dagan Galarneau, Horst Garnetzke, Petri
+    Kosunen, Mikael Caleres, and Frits Wilmink for reporting and
+    fixing bugs!
+
+(0.4) Changes since version 0.3.1
+
+  * Memory management has been radically changed; instead of
+    allocating memory from a shared heap, memory for objects that are
+    rapidly allocated and deallocated is now kept in pools. Allocation
+    and deallocation from those memory pools is very fast. The shared
+    heap is still present but is used less frequently.
+
+  * The memory, memory pool, and packet buffer subsystems now support
+    4-, 2-, or 1-byte alignment.
+
+  * "Out of memory" situations are handled in a more robust way.
+
+  * Stack usage has been reduced.
+
+  * Easier configuration of lwIP parameters such as memory usage,
+    TTLs, statistics gathering, etc. All configuration parameters are
+    now kept in a single header file "lwipopts.h".
+
+  * The directory structure has been changed slightly so that all
+    architecture specific files are kept under the src/arch
+    hierarchy.
+
+  * Error propagation has been improved, both in the protocol modules
+    and in the API.
+
+  * The code for the RTXC architecture has been implemented, tested
+    and put to use.
+
+  * Bugs have been found and corrected in the TCP, UDP, IP, API, and
+    the Internet checksum modules.
+
+  * Bugs related to porting between a 32-bit and a 16-bit architecture
+    have been found and corrected.
+
+  * The license has been changed slightly to conform more with the
+    original BSD license, including the advertisement clause.
+
+(0.3.1) Changes since version 0.3
+
+  * Fix of a fatal bug in the buffer management. Pbufs with allocated
+    RAM never returned the RAM when the pbuf was deallocated.
+
+  * TCP congestion control, window updates and retransmissions did not
+    work correctly. This has now been fixed.
+
+  * Bugfixes in the API.
+
+(0.3) Changes since version 0.2
+
+  * New and improved directory structure. All include files are now
+    kept in a dedicated include/ directory.
+
+  * The API now has proper error handling. A new function,
+    netconn_err(), now returns an error code for the connection in
+    case of errors.
+
+  * Improvements in the memory management subsystem. The system now
+    keeps a pointer to the lowest free memory block. A new function,
+    mem_malloc2() tries to allocate memory once, and if it fails tries
+    to free some memory and retry the allocation.
+
+  * Much testing has been done with limited memory
+    configurations. lwIP now does a better job when overloaded.
+
+  * Some bugfixes and improvements to the buffer (pbuf) subsystem.
+
+  * Many bugfixes in the TCP code:
+
+    - Fixed a bug in tcp_close().
+
+    - The TCP receive window was incorrectly closed when out of
+      sequence segments was received. This has been fixed.
+
+    - Connections are now timed-out of the FIN-WAIT-2 state.
+
+    - The initial congestion window could in some cases be too
+      large. This has been fixed.
+
+    - The retransmission queue could in some cases be screwed up. This
+      has been fixed.
+
+    - TCP RST flag now handled correctly.
+
+    - Out of sequence data was in some cases never delivered to the
+      application. This has been fixed.
+
+    - Retransmitted segments now contain the correct acknowledgment
+      number and advertised window.
+
+    - TCP retransmission timeout backoffs are not correctly computed
+      (ala BSD). After a number of retransmissions, TCP now gives up
+      the connection.
+
+  * TCP connections now are kept on three lists, one for active
+    connections, one for listening connections, and one for
+    connections that are in TIME-WAIT. This greatly speeds up the fast
+    timeout processing for sending delayed ACKs.
+
+  * TCP now provides proper feedback to the application when a
+    connection has been successfully set up.
+
+  * More comments have been added to the code. The code has also been
+    somewhat cleaned up.
+
+(0.2) Initial public release.
diff --git a/core/lwip/COPYING b/core/lwip/COPYING
new file mode 100644
index 00000000..e23898b5
--- /dev/null
+++ b/core/lwip/COPYING
@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2001, 2002 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+
diff --git a/core/lwip/FILES b/core/lwip/FILES
new file mode 100644
index 00000000..66253196
--- /dev/null
+++ b/core/lwip/FILES
@@ -0,0 +1,4 @@
+src/      - The source code for the lwIP TCP/IP stack.
+doc/      - The documentation for lwIP.
+
+See also the FILES file in each subdirectory.
diff --git a/core/lwip/README b/core/lwip/README
new file mode 100644
index 00000000..a62cc4f3
--- /dev/null
+++ b/core/lwip/README
@@ -0,0 +1,89 @@
+INTRODUCTION
+
+lwIP is a small independent implementation of the TCP/IP protocol
+suite that has been developed by Adam Dunkels at the Computer and
+Networks Architectures (CNA) lab at the Swedish Institute of Computer
+Science (SICS).
+
+The focus of the lwIP TCP/IP implementation is to reduce the RAM usage
+while still having a full scale TCP. This making lwIP suitable for use
+in embedded systems with tens of kilobytes of free RAM and room for
+around 40 kilobytes of code ROM.
+
+FEATURES
+
+  * IP (Internet Protocol) including packet forwarding over multiple network
+    interfaces
+  * ICMP (Internet Control Message Protocol) for network maintenance and debugging
+  * IGMP (Internet Group Management Protocol) for multicast traffic management
+  * UDP (User Datagram Protocol) including experimental UDP-lite extensions
+  * TCP (Transmission Control Protocol) with congestion control, RTT estimation
+    and fast recovery/fast retransmit
+  * Specialized raw/native API for enhanced performance
+  * Optional Berkeley-like socket API
+  * DNS (Domain names resolver)
+  * SNMP (Simple Network Management Protocol)
+  * DHCP (Dynamic Host Configuration Protocol)
+  * AUTOIP (for IPv4, conform with RFC 3927)
+  * PPP (Point-to-Point Protocol)
+  * ARP (Address Resolution Protocol) for Ethernet
+
+LICENSE
+
+lwIP is freely available under a BSD license.
+
+DEVELOPMENT
+
+lwIP has grown into an excellent TCP/IP stack for embedded devices,
+and developers using the stack often submit bug fixes, improvements,
+and additions to the stack to further increase its usefulness.
+
+Development of lwIP is hosted on Savannah, a central point for
+software development, maintenance and distribution. Everyone can
+help improve lwIP by use of Savannah's interface, CVS and the
+mailing list. A core team of developers will commit changes to the
+CVS source tree.
+
+The lwIP TCP/IP stack is maintained in the 'lwip' CVS module and
+contributions (such as platform ports) are in the 'contrib' module.
+
+See doc/savannah.txt for details on CVS server access for users and
+developers.
+
+Last night's CVS tar ball can be downloaded from:
+  http://savannah.gnu.org/cvs.backups/lwip.tar.gz [CHANGED - NEEDS FIXING]
+
+The current CVS trees are web-browsable:
+  http://savannah.nongnu.org/cgi-bin/viewcvs/lwip/lwip/
+  http://savannah.nongnu.org/cgi-bin/viewcvs/lwip/contrib/
+
+Submit patches and bugs via the lwIP project page:
+  http://savannah.nongnu.org/projects/lwip/
+
+
+DOCUMENTATION
+
+The original out-dated homepage of lwIP and Adam Dunkels' papers on
+lwIP are at the official lwIP home page:
+  http://www.sics.se/~adam/lwip/
+
+Self documentation of the source code is regularly extracted from the
+current CVS sources and is available from this web page:
+  http://www.nongnu.org/lwip/
+
+There is now a constantly growin wiki about lwIP at
+  http://lwip.wikia.com/wiki/LwIP_Wiki
+
+Also, there are mailing lists you can subscribe at
+  http://savannah.nongnu.org/mail/?group=lwip
+plus searchable archives:
+  http://lists.nongnu.org/archive/html/lwip-users/
+  http://lists.nongnu.org/archive/html/lwip-devel/
+
+Reading Adam's papers, the files in docs/, browsing the source code
+documentation and browsing the mailing list archives is a good way to
+become familiar with the design of lwIP.
+
+Adam Dunkels <adam@sics.se>
+Leon Woestenberg <leon.woestenberg@gmx.net>
+
diff --git a/core/lwip/UPGRADING b/core/lwip/UPGRADING
new file mode 100644
index 00000000..6501107a
--- /dev/null
+++ b/core/lwip/UPGRADING
@@ -0,0 +1,144 @@
+This file lists major changes between release versions that require
+ports or applications to be changed. Use it to update a port or an
+application written for an older version of lwIP to correctly work
+with newer versions.
+
+
+(CVS HEAD)
+
+  * [Enter new changes just after this line - do not remove this line]
+
+  ++ Application changes:
+
+  * Replaced struct ip_addr by typedef ip_addr_t (struct ip_addr is kept for
+    compatibility to old applications, but will be removed in the future).
+
+  * Renamed mem_realloc() to mem_trim() to prevent confusion with realloc()
+
+  +++ Raw API:
+    * Changed the semantics of tcp_close() (since it was rather a
+      shutdown before): Now the application does *NOT* get any calls to the recv
+      callback (aside from NULL/closed) after calling tcp_close()
+
+    * When calling tcp_abort() from a raw API TCP callback function,
+      make sure you return ERR_ABRT to prevent accessing unallocated memory.
+      (ERR_ABRT now means the applicaiton has called tcp_abort!)
+
+  +++ Netconn API:
+    * Changed netconn_receive() and netconn_accept() to return
+      err_t, not a pointer to new data/netconn.
+
+  +++ Socket API:
+    * LWIP_SO_RCVTIMEO: when accept() or recv() time out, they
+      now set errno to EWOULDBLOCK/EAGAIN, not ETIMEDOUT.
+
+    * Added a minimal version of posix fctl() to have a
+      standardised way to set O_NONBLOCK for nonblocking sockets.
+
+  +++ all APIs:
+    * correctly implemented SO(F)_REUSEADDR
+
+  ++ Port changes
+
+  +++ new files:
+
+    * Added 4 new files: def.c, timers.c, timers.h, tcp_impl.h:
+
+    * Moved stack-internal parts of tcp.h to tcp_impl.h, tcp.h now only contains
+      the actual application programmer's API
+  
+    * Separated timer implementation from sys.h/.c, moved to timers.h/.c;
+      Added timer implementation for NO_SYS==1, set NO_SYS_NO_TIMERS==1 if you
+      still want to use your own timer implementation for NO_SYS==0 (as before).
+
+  +++ sys layer:
+
+    * Converted mbox- and semaphore-functions to take pointers to sys_mbox_t/
+      sys_sem_t;
+
+    * Converted sys_mbox_new/sys_sem_new to take pointers and return err_t;
+
+    * Added Mutex concept in sys_arch (define LWIP_COMPAT_MUTEX to let sys.h use
+      binary semaphores instead of mutexes - as before)
+
+  +++ new options:
+
+     * Don't waste memory when chaining segments, added option TCP_OVERSIZE to
+       prevent creating many small pbufs when calling tcp_write with many small
+       blocks of data. Instead, pbufs are allocated larger than needed and the
+       space is used for later calls to tcp_write.
+
+     * Added LWIP_NETIF_TX_SINGLE_PBUF to always copy to try to create single pbufs
+       in tcp_write/udp_send.
+
+    * Added an additional option LWIP_ETHERNET to support ethernet without ARP
+      (necessary for pure PPPoE)
+
+    * Add MEMP_SEPARATE_POOLS to place memory pools in separate arrays. This may
+      be used to place these pools into user-defined memory by using external
+      declaration.
+
+    * Added TCP_SNDQUEUELOWAT corresponding to TCP_SNDLOWAT
+
+  +++ new pools:
+
+     * Netdb uses a memp pool for allocating memory when getaddrinfo() is called,
+       so MEMP_NUM_NETDB has to be set accordingly.
+
+     * DNS_LOCAL_HOSTLIST_IS_DYNAMIC uses a memp pool instead of the heap, so
+       MEMP_NUM_LOCALHOSTLIST has to be set accordingly.
+
+     * Snmp-agent uses a memp pools instead of the heap, so MEMP_NUM_SNMP_* have
+       to be set accordingly.
+
+     * PPPoE uses a MEMP pool instead of the heap, so MEMP_NUM_PPPOE_INTERFACES
+       has to be set accordingly
+
+  * Integrated loopif into netif.c - loopif does not have to be created by the
+    port any more, just define LWIP_HAVE_LOOPIF to 1.
+
+  * Added define LWIP_RAND() for lwip-wide randomization (needs to be defined
+    in cc.h, e.g. used by igmp)
+
+  * Added printf-formatter X8_F to printf u8_t as hex
+
+  * The heap now may be moved to user-defined memory by defining
+    LWIP_RAM_HEAP_POINTER as a void pointer to that memory's address
+
+  * added autoip_set_struct() and dhcp_set_struct() to let autoip and dhcp work
+    with user-allocated structs instead of calling mem_malloc
+
+  * Added const char* name to mem- and memp-stats for easier debugging.
+
+  * Calculate the TCP/UDP checksum while copying to only fetch data once:
+    Define LWIP_CHKSUM_COPY to a memcpy-like function that returns the checksum
+
+  * Added SO_REUSE_RXTOALL to pass received UDP broadcast/multicast packets to
+    more than one pcb.
+
+  * Changed the semantics of ARP_QUEUEING==0: ARP_QUEUEING now cannot be turned
+    off any more, if this is set to 0, only one packet (the most recent one) is
+    queued (like demanded by RFC 1122).
+
+  
+  ++ Major bugfixes/improvements
+
+  * Implemented tcp_shutdown() to only shut down one end of a connection
+  * Implemented shutdown() at socket- and netconn-level
+  * Added errorset support to select() + improved select speed overhead
+  * Merged pppd to v2.3.11 (including some backported bugfixes from 2.4.x)
+  * Added timer implementation for NO_SYS==1 (may be disabled with NO_SYS_NO_TIMERS==1
+  * Use macros defined in ip_addr.h to work with IP addresses
+  * Implemented many nonblocking socket/netconn functions
+  * Fixed ARP input processing: only add a new entry if a request was directed as us
+  * mem_realloc() to mem_trim() to prevent confusion with realloc()
+  * Some improvements for AutoIP (don't route/forward link-local addresses, don't break
+    existing connections when assigning a routable address)
+  * Correctly handle remote side overrunning our rcv_wnd in ooseq case
+  * Removed packing from ip_addr_t, the packed version is now only used in protocol headers
+  * Corrected PBUF_POOL_BUFSIZE for ports where ETH_PAD_SIZE > 0
+  * Added support for static ARP table entries
+
+(STABLE-1.3.2)
+
+  * initial version of this file
diff --git a/core/lwip/doc/FILES b/core/lwip/doc/FILES
new file mode 100644
index 00000000..05d356f4
--- /dev/null
+++ b/core/lwip/doc/FILES
@@ -0,0 +1,6 @@
+savannah.txt   - How to obtain the current development source code.
+contrib.txt    - How to contribute to lwIP as a developer.
+rawapi.txt     - The documentation for the core API of lwIP.
+                 Also provides an overview about the other APIs and multithreading.
+snmp_agent.txt - The documentation for the lwIP SNMP agent.
+sys_arch.txt   - The documentation for a system abstraction layer of lwIP.
diff --git a/core/lwip/doc/contrib.txt b/core/lwip/doc/contrib.txt
new file mode 100644
index 00000000..39596fca
--- /dev/null
+++ b/core/lwip/doc/contrib.txt
@@ -0,0 +1,63 @@
+1 Introduction
+
+This document describes some guidelines for people participating
+in lwIP development.
+
+2 How to contribute to lwIP
+
+Here is a short list of suggestions to anybody working with lwIP and 
+trying to contribute bug reports, fixes, enhancements, platform ports etc.
+First of all as you may already know lwIP is a volunteer project so feedback
+to fixes or questions might often come late. Hopefully the bug and patch tracking 
+features of Savannah help us not lose users' input.
+
+2.1 Source code style:
+
+1. do not use tabs.
+2. indentation is two spaces per level (i.e. per tab).
+3. end debug messages with a trailing newline (\n).
+4. one space between keyword and opening bracket.
+5. no space between function and opening bracket.
+6. one space and no newline before opening curly braces of a block.
+7. closing curly brace on a single line.
+8. spaces surrounding assignment and comparisons.
+9. don't initialize static and/or global variables to zero, the compiler takes care of that.
+10. use current source code style as further reference.
+
+2.2 Source code documentation style:
+
+1. JavaDoc compliant and Doxygen compatible.
+2. Function documentation above functions in .c files, not .h files.
+   (This forces you to synchronize documentation and implementation.)
+3. Use current documentation style as further reference.
+ 
+2.3 Bug reports and patches:
+
+1. Make sure you are reporting bugs or send patches against the latest
+   sources. (From the latest release and/or the current CVS sources.)
+2. If you think you found a bug make sure it's not already filed in the
+   bugtracker at Savannah.
+3. If you have a fix put the patch on Savannah. If it is a patch that affects
+   both core and arch specific stuff please separate them so that the core can
+   be applied separately while leaving the other patch 'open'. The prefered way
+   is to NOT touch archs you can't test and let maintainers take care of them.
+   This is a good way to see if they are used at all - the same goes for unix
+   netifs except tapif.
+4. Do not file a bug and post a fix to it to the patch area. Either a bug report
+   or a patch will be enough.
+   If you correct an existing bug then attach the patch to the bug rather than creating a new entry in the patch area.
+5. Trivial patches (compiler warning, indentation and spelling fixes or anything obvious which takes a line or two)
+   can go to the lwip-users list. This is still the fastest way of interaction and the list is not so crowded
+   as to allow for loss of fixes. Putting bugs on Savannah and subsequently closing them is too much an overhead
+   for reporting a compiler warning fix.
+6. Patches should be specific to a single change or to related changes.Do not mix bugfixes with spelling and other
+   trivial fixes unless the bugfix is trivial too.Do not reorganize code and rename identifiers in the same patch you
+   change behaviour if not necessary.A patch is easier to read and understand if it's to the point and short than
+   if it's not to the point and long :) so the chances for it to be applied are greater. 
+
+2.4 Platform porters:
+
+1. If you have ported lwIP to a platform (an OS, a uC/processor or a combination of these) and
+   you think it could benefit others[1] you might want discuss this on the mailing list. You
+   can also ask for CVS access to submit and maintain your port in the contrib CVS module.
+   
\ No newline at end of file
diff --git a/core/lwip/doc/rawapi.txt b/core/lwip/doc/rawapi.txt
new file mode 100644
index 00000000..c727da99
--- /dev/null
+++ b/core/lwip/doc/rawapi.txt
@@ -0,0 +1,505 @@
+Raw TCP/IP interface for lwIP
+
+Authors: Adam Dunkels, Leon Woestenberg, Christiaan Simons
+
+lwIP provides three Application Program's Interfaces (APIs) for programs
+to use for communication with the TCP/IP code:
+* low-level "core" / "callback" or "raw" API.
+* higher-level "sequential" API.
+* BSD-style socket API.
+
+The sequential API provides a way for ordinary, sequential, programs
+to use the lwIP stack. It is quite similar to the BSD socket API. The
+model of execution is based on the blocking open-read-write-close
+paradigm. Since the TCP/IP stack is event based by nature, the TCP/IP
+code and the application program must reside in different execution
+contexts (threads).
+
+The socket API is a compatibility API for existing applications,
+currently it is built on top of the sequential API. It is meant to
+provide all functions needed to run socket API applications running
+on other platforms (e.g. unix / windows etc.). However, due to limitations
+in the specification of this API, there might be incompatibilities
+that require small modifications of existing programs.
+
+** Threading
+
+lwIP started targeting single-threaded environments. When adding multi-
+threading support, instead of making the core thread-safe, another
+approach was chosen: there is one main thread running the lwIP core
+(also known as the "tcpip_thread"). The raw API may only be used from
+this thread! Application threads using the sequential- or socket API
+communicate with this main thread through message passing.
+
+      As such, the list of functions that may be called from
+      other threads or an ISR is very limited! Only functions
+      from these API header files are thread-safe:
+      - api.h
+      - netbuf.h
+      - netdb.h
+      - netifapi.h
+      - sockets.h
+      - sys.h
+
+      Additionaly, memory (de-)allocation functions may be
+      called from multiple threads (not ISR!) with NO_SYS=0
+      since they are protected by SYS_LIGHTWEIGHT_PROT and/or
+      semaphores.
+
+      Only since 1.3.0, if SYS_LIGHTWEIGHT_PROT is set to 1
+      and LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT is set to 1,
+      pbuf_free() may also be called from another thread or
+      an ISR (since only then, mem_free - for PBUF_RAM - may
+      be called from an ISR: otherwise, the HEAP is only
+      protected by semaphores).
+      
+
+** The remainder of this document discusses the "raw" API. **
+
+The raw TCP/IP interface allows the application program to integrate
+better with the TCP/IP code. Program execution is event based by
+having callback functions being called from within the TCP/IP
+code. The TCP/IP code and the application program both run in the same
+thread. The sequential API has a much higher overhead and is not very
+well suited for small systems since it forces a multithreaded paradigm
+on the application.
+
+The raw TCP/IP interface is not only faster in terms of code execution
+time but is also less memory intensive. The drawback is that program
+development is somewhat harder and application programs written for
+the raw TCP/IP interface are more difficult to understand. Still, this
+is the preferred way of writing applications that should be small in
+code size and memory usage.
+
+Both APIs can be used simultaneously by different application
+programs. In fact, the sequential API is implemented as an application
+program using the raw TCP/IP interface.
+
+--- Callbacks
+
+Program execution is driven by callbacks. Each callback is an ordinary
+C function that is called from within the TCP/IP code. Every callback
+function is passed the current TCP or UDP connection state as an
+argument. Also, in order to be able to keep program specific state,
+the callback functions are called with a program specified argument
+that is independent of the TCP/IP state.
+
+The function for setting the application connection state is:
+
+- void tcp_arg(struct tcp_pcb *pcb, void *arg)
+
+  Specifies the program specific state that should be passed to all
+  other callback functions. The "pcb" argument is the current TCP
+  connection control block, and the "arg" argument is the argument
+  that will be passed to the callbacks.
+
+  
+--- TCP connection setup
+
+The functions used for setting up connections is similar to that of
+the sequential API and of the BSD socket API. A new TCP connection
+identifier (i.e., a protocol control block - PCB) is created with the
+tcp_new() function. This PCB can then be either set to listen for new
+incoming connections or be explicitly connected to another host.
+
+- struct tcp_pcb *tcp_new(void)
+
+  Creates a new connection identifier (PCB). If memory is not
+  available for creating the new pcb, NULL is returned.
+
+- err_t tcp_bind(struct tcp_pcb *pcb, struct ip_addr *ipaddr,
+                 u16_t port)
+
+  Binds the pcb to a local IP address and port number. The IP address
+  can be specified as IP_ADDR_ANY in order to bind the connection to
+  all local IP addresses.
+
+  If another connection is bound to the same port, the function will
+  return ERR_USE, otherwise ERR_OK is returned.
+
+- struct tcp_pcb *tcp_listen(struct tcp_pcb *pcb)
+
+  Commands a pcb to start listening for incoming connections. When an
+  incoming connection is accepted, the function specified with the
+  tcp_accept() function will be called. The pcb will have to be bound
+  to a local port with the tcp_bind() function.
+
+  The tcp_listen() function returns a new connection identifier, and
+  the one passed as an argument to the function will be
+  deallocated. The reason for this behavior is that less memory is
+  needed for a connection that is listening, so tcp_listen() will
+  reclaim the memory needed for the original connection and allocate a
+  new smaller memory block for the listening connection.
+
+  tcp_listen() may return NULL if no memory was available for the
+  listening connection. If so, the memory associated with the pcb
+  passed as an argument to tcp_listen() will not be deallocated.
+
+- struct tcp_pcb *tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog)
+
+  Same as tcp_listen, but limits the number of outstanding connections
+  in the listen queue to the value specified by the backlog argument.
+  To use it, your need to set TCP_LISTEN_BACKLOG=1 in your lwipopts.h.
+
+- void tcp_accepted(struct tcp_pcb *pcb)
+
+  Inform lwIP that an incoming connection has been accepted. This would
+  usually be called from the accept callback. This allows lwIP to perform
+  housekeeping tasks, such as allowing further incoming connections to be
+  queued in the listen backlog.
+
+- void tcp_accept(struct tcp_pcb *pcb,
+                  err_t (* accept)(void *arg, struct tcp_pcb *newpcb,
+                                   err_t err))
+
+  Specified the callback function that should be called when a new
+  connection arrives on a listening connection.
+      
+- err_t tcp_connect(struct tcp_pcb *pcb, struct ip_addr *ipaddr,
+                    u16_t port, err_t (* connected)(void *arg,
+                                                    struct tcp_pcb *tpcb,
+                                                    err_t err));
+
+  Sets up the pcb to connect to the remote host and sends the
+  initial SYN segment which opens the connection. 
+
+  The tcp_connect() function returns immediately; it does not wait for
+  the connection to be properly setup. Instead, it will call the
+  function specified as the fourth argument (the "connected" argument)
+  when the connection is established. If the connection could not be
+  properly established, either because the other host refused the
+  connection or because the other host didn't answer, the "err"
+  callback function of this pcb (registered with tcp_err, see below)
+  will be called.
+
+  The tcp_connect() function can return ERR_MEM if no memory is
+  available for enqueueing the SYN segment. If the SYN indeed was
+  enqueued successfully, the tcp_connect() function returns ERR_OK.
+
+  
+--- Sending TCP data
+
+TCP data is sent by enqueueing the data with a call to
+tcp_write(). When the data is successfully transmitted to the remote
+host, the application will be notified with a call to a specified
+callback function.
+
+- err_t tcp_write(struct tcp_pcb *pcb, void *dataptr, u16_t len,
+                  u8_t copy)
+
+  Enqueues the data pointed to by the argument dataptr. The length of
+  the data is passed as the len parameter. The copy argument is either
+  0 or 1 and indicates whether the new memory should be allocated for
+  the data to be copied into. If the argument is 0, no new memory
+  should be allocated and the data should only be referenced by
+  pointer.
+
+  The tcp_write() function will fail and return ERR_MEM if the length
+  of the data exceeds the current send buffer size or if the length of
+  the queue of outgoing segment is larger than the upper limit defined
+  in lwipopts.h. The number of bytes available in the output queue can
+  be retrieved with the tcp_sndbuf() function.
+
+  The proper way to use this function is to call the function with at
+  most tcp_sndbuf() bytes of data. If the function returns ERR_MEM,
+  the application should wait until some of the currently enqueued
+  data has been successfully received by the other host and try again.
+
+- void tcp_sent(struct tcp_pcb *pcb,
+                err_t (* sent)(void *arg, struct tcp_pcb *tpcb,
+                u16_t len))
+
+  Specifies the callback function that should be called when data has
+  successfully been received (i.e., acknowledged) by the remote
+  host. The len argument passed to the callback function gives the
+  amount bytes that was acknowledged by the last acknowledgment.
+
+  
+--- Receiving TCP data
+
+TCP data reception is callback based - an application specified
+callback function is called when new data arrives. When the
+application has taken the data, it has to call the tcp_recved()
+function to indicate that TCP can advertise increase the receive
+window.
+
+- void tcp_recv(struct tcp_pcb *pcb,
+                err_t (* recv)(void *arg, struct tcp_pcb *tpcb,
+                               struct pbuf *p, err_t err))
+
+  Sets the callback function that will be called when new data
+  arrives. The callback function will be passed a NULL pbuf to
+  indicate that the remote host has closed the connection. If
+  there are no errors and the callback function is to return
+  ERR_OK, then it must free the pbuf. Otherwise, it must not
+  free the pbuf so that lwIP core code can store it.
+
+- void tcp_recved(struct tcp_pcb *pcb, u16_t len)
+
+  Must be called when the application has received the data. The len
+  argument indicates the length of the received data.
+    
+
+--- Application polling
+
+When a connection is idle (i.e., no data is either transmitted or
+received), lwIP will repeatedly poll the application by calling a
+specified callback function. This can be used either as a watchdog
+timer for killing connections that have stayed idle for too long, or
+as a method of waiting for memory to become available. For instance,
+if a call to tcp_write() has failed because memory wasn't available,
+the application may use the polling functionality to call tcp_write()
+again when the connection has been idle for a while.
+
+- void tcp_poll(struct tcp_pcb *pcb, 
+                err_t (* poll)(void *arg, struct tcp_pcb *tpcb),
+				u8_t interval)
+
+  Specifies the polling interval and the callback function that should
+  be called to poll the application. The interval is specified in
+  number of TCP coarse grained timer shots, which typically occurs
+  twice a second. An interval of 10 means that the application would
+  be polled every 5 seconds.
+
+
+--- Closing and aborting connections
+
+- err_t tcp_close(struct tcp_pcb *pcb)
+
+  Closes the connection. The function may return ERR_MEM if no memory
+  was available for closing the connection. If so, the application
+  should wait and try again either by using the acknowledgment
+  callback or the polling functionality. If the close succeeds, the
+  function returns ERR_OK.
+
+  The pcb is deallocated by the TCP code after a call to tcp_close(). 
+
+- void tcp_abort(struct tcp_pcb *pcb)
+
+  Aborts the connection by sending a RST (reset) segment to the remote
+  host. The pcb is deallocated. This function never fails.
+
+  ATTENTION: When calling this from one of the TCP callbacks, make
+  sure you always return ERR_ABRT (and never return ERR_ABRT otherwise
+  or you will risk accessing deallocated memory or memory leaks!
+
+
+If a connection is aborted because of an error, the application is
+alerted of this event by the err callback. Errors that might abort a
+connection are when there is a shortage of memory. The callback
+function to be called is set using the tcp_err() function.
+
+- void tcp_err(struct tcp_pcb *pcb, void (* err)(void *arg,
+       err_t err))
+
+  The error callback function does not get the pcb passed to it as a
+  parameter since the pcb may already have been deallocated.
+
+
+--- Lower layer TCP interface
+
+TCP provides a simple interface to the lower layers of the
+system. During system initialization, the function tcp_init() has
+to be called before any other TCP function is called. When the system
+is running, the two timer functions tcp_fasttmr() and tcp_slowtmr()
+must be called with regular intervals. The tcp_fasttmr() should be
+called every TCP_FAST_INTERVAL milliseconds (defined in tcp.h) and
+tcp_slowtmr() should be called every TCP_SLOW_INTERVAL milliseconds. 
+
+
+--- UDP interface
+
+The UDP interface is similar to that of TCP, but due to the lower
+level of complexity of UDP, the interface is significantly simpler.
+
+- struct udp_pcb *udp_new(void)
+
+  Creates a new UDP pcb which can be used for UDP communication. The
+  pcb is not active until it has either been bound to a local address
+  or connected to a remote address.
+
+- void udp_remove(struct udp_pcb *pcb)
+
+  Removes and deallocates the pcb.  
+  
+- err_t udp_bind(struct udp_pcb *pcb, struct ip_addr *ipaddr,
+                 u16_t port)
+
+  Binds the pcb to a local address. The IP-address argument "ipaddr"
+  can be IP_ADDR_ANY to indicate that it should listen to any local IP
+  address. The function currently always return ERR_OK.
+
+- err_t udp_connect(struct udp_pcb *pcb, struct ip_addr *ipaddr,
+                    u16_t port)
+
+  Sets the remote end of the pcb. This function does not generate any
+  network traffic, but only set the remote address of the pcb.
+
+- err_t udp_disconnect(struct udp_pcb *pcb)
+
+  Remove the remote end of the pcb. This function does not generate
+  any network traffic, but only removes the remote address of the pcb.
+
+- err_t udp_send(struct udp_pcb *pcb, struct pbuf *p)
+
+  Sends the pbuf p. The pbuf is not deallocated.
+
+- void udp_recv(struct udp_pcb *pcb,
+                void (* recv)(void *arg, struct udp_pcb *upcb,
+                                         struct pbuf *p,
+                                         struct ip_addr *addr,
+                                         u16_t port),
+                              void *recv_arg)
+
+  Specifies a callback function that should be called when a UDP
+  datagram is received.
+  
+
+--- System initalization
+
+A truly complete and generic sequence for initializing the lwip stack
+cannot be given because it depends on the build configuration (lwipopts.h)
+and additional initializations for your runtime environment (e.g. timers).
+
+We can give you some idea on how to proceed when using the raw API.
+We assume a configuration using a single Ethernet netif and the
+UDP and TCP transport layers, IPv4 and the DHCP client.
+
+Call these functions in the order of appearance:
+
+- stats_init()
+
+  Clears the structure where runtime statistics are gathered.
+
+- sys_init()
+  
+  Not of much use since we set the NO_SYS 1 option in lwipopts.h,
+  to be called for easy configuration changes.
+
+- lwip_mem_init()
+
+  Initializes the dynamic memory heap defined by MEM_SIZE.
+
+- memp_init()
+
+  Initializes the memory pools defined by MEMP_NUM_x.
+
+- pbuf_init()
+
+  Initializes the pbuf memory pool defined by PBUF_POOL_SIZE.
+  
+- etharp_init()
+
+  Initializes the ARP table and queue.
+  Note: you must call etharp_tmr at a ARP_TMR_INTERVAL (5 seconds) regular interval
+  after this initialization.
+
+- ip_init()
+
+  Doesn't do much, it should be called to handle future changes.
+
+- udp_init()
+
+  Clears the UDP PCB list.
+
+- tcp_init()
+
+  Clears the TCP PCB list and clears some internal TCP timers.
+  Note: you must call tcp_fasttmr() and tcp_slowtmr() at the
+  predefined regular intervals after this initialization. 
+  
+- netif_add(struct netif *netif, struct ip_addr *ipaddr,
+            struct ip_addr *netmask, struct ip_addr *gw,
+            void *state, err_t (* init)(struct netif *netif),
+            err_t (* input)(struct pbuf *p, struct netif *netif))
+
+  Adds your network interface to the netif_list. Allocate a struct
+  netif and pass a pointer to this structure as the first argument.
+  Give pointers to cleared ip_addr structures when using DHCP,
+  or fill them with sane numbers otherwise. The state pointer may be NULL.
+
+  The init function pointer must point to a initialization function for
+  your ethernet netif interface. The following code illustrates it's use.
+  
+  err_t netif_if_init(struct netif *netif)
+  {
+    u8_t i;
+    
+    for(i = 0; i < ETHARP_HWADDR_LEN; i++) netif->hwaddr[i] = some_eth_addr[i];
+    init_my_eth_device();
+    return ERR_OK;
+  }
+  
+  For ethernet drivers, the input function pointer must point to the lwip
+  function ethernet_input() declared in "netif/etharp.h". Other drivers
+  must use ip_input() declared in "lwip/ip.h".
+  
+- netif_set_default(struct netif *netif)
+
+  Registers the default network interface.
+
+- netif_set_up(struct netif *netif)
+
+  When the netif is fully configured this function must be called.
+
+- dhcp_start(struct netif *netif)
+
+  Creates a new DHCP client for this interface on the first call.
+  Note: you must call dhcp_fine_tmr() and dhcp_coarse_tmr() at
+  the predefined regular intervals after starting the client.
+  
+  You can peek in the netif->dhcp struct for the actual DHCP status.
+
+
+--- Optimalization hints
+
+The first thing you want to optimize is the lwip_standard_checksum()
+routine from src/core/inet.c. You can override this standard
+function with the #define LWIP_CHKSUM <your_checksum_routine>.
+
+There are C examples given in inet.c or you might want to
+craft an assembly function for this. RFC1071 is a good
+introduction to this subject.
+
+Other significant improvements can be made by supplying
+assembly or inline replacements for htons() and htonl()
+if you're using a little-endian architecture.
+#define LWIP_PLATFORM_BYTESWAP 1
+#define LWIP_PLATFORM_HTONS(x) <your_htons>
+#define LWIP_PLATFORM_HTONL(x) <your_htonl>
+
+Check your network interface driver if it reads at
+a higher speed than the maximum wire-speed. If the
+hardware isn't serviced frequently and fast enough
+buffer overflows are likely to occur.
+
+E.g. when using the cs8900 driver, call cs8900if_service(ethif)
+as frequently as possible. When using an RTOS let the cs8900 interrupt
+wake a high priority task that services your driver using a binary
+semaphore or event flag. Some drivers might allow additional tuning
+to match your application and network.
+
+For a production release it is recommended to set LWIP_STATS to 0.
+Note that speed performance isn't influenced much by simply setting
+high values to the memory options.
+
+For more optimization hints take a look at the lwIP wiki.
+
+--- Zero-copy MACs
+
+To achieve zero-copy on transmit, the data passed to the raw API must
+remain unchanged until sent. Because the send- (or write-)functions return
+when the packets have been enqueued for sending, data must be kept stable
+after that, too.
+
+This implies that PBUF_RAM/PBUF_POOL pbufs passed to raw-API send functions
+must *not* be reused by the application unless their ref-count is 1.
+
+For no-copy pbufs (PBUF_ROM/PBUF_REF), data must be kept unchanged, too,
+but the stack/driver will/must copy PBUF_REF'ed data when enqueueing, while
+PBUF_ROM-pbufs are just enqueued (as ROM-data is expected to never change).
+
+Also, data passed to tcp_write without the copy-flag must not be changed!
+
+Therefore, be careful which type of PBUF you use and if you copy TCP data
+or not!
diff --git a/core/lwip/doc/savannah.txt b/core/lwip/doc/savannah.txt
new file mode 100644
index 00000000..409905b1
--- /dev/null
+++ b/core/lwip/doc/savannah.txt
@@ -0,0 +1,135 @@
+Daily Use Guide for using Savannah for lwIP
+
+Table of Contents:
+
+1 - Obtaining lwIP from the CVS repository
+2 - Committers/developers CVS access using SSH (to be written)
+3 - Merging from DEVEL branch to main trunk (stable branch)
+4 - How to release lwIP
+
+
+
+1 Obtaining lwIP from the CVS repository
+----------------------------------------
+
+To perform an anonymous CVS checkout of the main trunk (this is where
+bug fixes and incremental enhancements occur), do this:
+
+cvs -z3 -d:pserver:anonymous@cvs.sv.gnu.org:/sources/lwip checkout lwip
+ 
+Or, obtain a stable branch (updated with bug fixes only) as follows:
+cvs -z3 -d:pserver:anonymous@cvs.sv.gnu.org:/sources/lwip checkout \
+  -r STABLE-0_7 -d lwip-0.7 lwip
+
+Or, obtain a specific (fixed) release as follows:
+cvs -z3 -d:pserver:anonymous@cvs.sv.gnu.org:/sources/lwip checkout \
+  -r STABLE-0_7_0 -d lwip-0.7.0 lwip
+
+3 Committers/developers CVS access using SSH
+--------------------------------------------
+
+The Savannah server uses SSH (Secure Shell) protocol 2 authentication and encryption.
+As such, CVS commits to the server occur through a SSH tunnel for project members.
+To create a SSH2 key pair in UNIX-like environments, do this:
+
+ssh-keygen -t dsa
+
+Under Windows, a recommended SSH client is "PuTTY", freely available with good
+documentation and a graphic user interface. Use its key generator.
+
+Now paste the id_dsa.pub contents into your Savannah account public key list. Wait
+a while so that Savannah can update its configuration (This can take minutes).
+
+Try to login using SSH:
+
+ssh -v your_login@cvs.sv.gnu.org
+
+If it tells you:
+
+Authenticating with public key "your_key_name"...
+Server refused to allocate pty
+
+then you could login; Savannah refuses to give you a shell - which is OK, as we
+are allowed to use SSH for CVS only. Now, you should be able to do this:
+
+export CVS_RSH=ssh
+cvs -z3 -d:ext:your_login@cvs.sv.gnu.org:/sources/lwip co lwip
+ 
+after which you can edit your local files with bug fixes or new features and
+commit them. Make sure you know what you are doing when using CVS to make
+changes on the repository. If in doubt, ask on the lwip-members mailing list.
+
+(If SSH asks about authenticity of the host, you can check the key
+ fingerprint against http://savannah.nongnu.org/cvs/?group=lwip)
+
+
+3 Merging from DEVEL branch to main trunk (stable)
+--------------------------------------------------
+
+Merging is a delicate process in CVS and requires the
+following disciplined steps in order to prevent conflicts
+in the future. Conflicts can be hard to solve!
+
+Merging from branch A to branch B requires that the A branch
+has a tag indicating the previous merger. This tag is called
+'merged_from_A_to_B'. After merging, the tag is moved in the
+A branch to remember this merger for future merge actions.
+
+IMPORTANT: AFTER COMMITTING A SUCCESFUL MERGE IN THE
+REPOSITORY, THE TAG MUST BE SET ON THE SOURCE BRANCH OF THE
+MERGE ACTION (REPLACING EXISTING TAGS WITH THE SAME NAME).
+
+Merge all changes in DEVEL since our last merge to main:
+
+In the working copy of the main trunk:
+cvs update -P -jmerged_from_DEVEL_to_main -jDEVEL 
+
+(This will apply the changes between 'merged_from_DEVEL_to_main'
+and 'DEVEL' to your work set of files)
+
+We can now commit the merge result.
+cvs commit -R -m "Merged from DEVEL to main." 
+
+If this worked out OK, we now move the tag in the DEVEL branch
+to this merge point, so we can use this point for future merges:
+
+cvs rtag -F -r DEVEL merged_from_DEVEL_to_main lwip 
+
+4 How to release lwIP
+---------------------
+
+First, checkout a clean copy of the branch to be released. Tag this set with
+tag name "STABLE-0_6_3". (I use release number 0.6.3 throughout this example).
+
+Login CVS using pserver authentication, then export a clean copy of the
+tagged tree. Export is similar to a checkout, except that the CVS metadata
+is not created locally. 
+
+export CVS_RSH=ssh
+cvs -z3 -d:pserver:anonymous@cvs.sv.gnu.org:/sources/lwip checkout \
+  -r STABLE-0_6_3 -d lwip-0.6.3 lwip
+
+Archive this directory using tar, gzip'd, bzip2'd and zip'd.
+
+tar czvf lwip-0.6.3.tar.gz lwip-0.6.3
+tar cjvf lwip-0.6.3.tar.bz2 lwip-0.6.3
+zip -r lwip-0.6.3.zip lwip-0.6.3
+
+Now, sign the archives with a detached GPG binary signature as follows:
+
+gpg -b lwip-0.6.3.tar.gz
+gpg -b lwip-0.6.3.tar.bz2
+gpg -b lwip-0.6.3.zip
+
+Upload these files using anonymous FTP:
+ncftp ftp://savannah.gnu.org/incoming/savannah/lwip
+
+ncftp>mput *0.6.3.*
+
+Additionally, you may post a news item on Savannah, like this:
+
+A new 0.6.3 release is now available here:
+http://savannah.nongnu.org/files/?group=lwip&highlight=0.6.3
+
+You will have to submit this via the user News interface, then approve
+this via the Administrator News interface.
\ No newline at end of file
diff --git a/core/lwip/doc/snmp_agent.txt b/core/lwip/doc/snmp_agent.txt
new file mode 100644
index 00000000..2653230f
--- /dev/null
+++ b/core/lwip/doc/snmp_agent.txt
@@ -0,0 +1,181 @@
+SNMPv1 agent for lwIP
+
+Author: Christiaan Simons
+
+This is a brief introduction how to use and configure the SNMP agent.
+Note the agent uses the raw-API UDP interface so you may also want to
+read rawapi.txt to gain a better understanding of the SNMP message handling.
+
+0 Agent Capabilities
+====================
+
+SNMPv1 per RFC1157
+  This is an old(er) standard but is still widely supported.
+  For SNMPv2c and v3 have a greater complexity and need many
+  more lines of code. IMHO this breaks the idea of "lightweight IP".
+
+  Note the S in SNMP stands for "Simple". Note that "Simple" is
+  relative. SNMP is simple compared to the complex ISO network
+  management protocols CMIP (Common Management Information Protocol)
+  and CMOT (CMip Over Tcp).
+
+MIB II per RFC1213
+  The standard lwIP stack management information base.
+  This is a required MIB, so this is always enabled.
+  When builing lwIP without TCP, the mib-2.tcp group is omitted.
+  The groups EGP, CMOT and transmission are disabled by default.
+  
+  Most mib-2 objects are not writable except:
+  sysName, sysLocation, sysContact, snmpEnableAuthenTraps.
+  Writing to or changing the ARP and IP address and route
+  tables is not possible.
+ 
+  Note lwIP has a very limited notion of IP routing. It currently
+  doen't have a route table and doesn't have a notion of the U,G,H flags.
+  Instead lwIP uses the interface list with only one default interface
+  acting as a single gateway interface (G) for the default route.
+
+  The agent returns a "virtual table" with the default route 0.0.0.0
+  for the default interface and network routes (no H) for each
+  network interface in the netif_list.
+  All routes are considered to be up (U).
+
+Loading additional MIBs
+  MIBs can only be added in compile-time, not in run-time.
+  There is no MIB compiler thus additional MIBs must be hand coded.
+
+Large SNMP message support
+  The packet decoding and encoding routines are designed
+  to use pbuf-chains. Larger payloads than the minimum
+  SNMP requirement of 484 octets are supported if the 
+  PBUF_POOL_SIZE and IP_REASS_BUFSIZE are set to match your
+  local requirement.
+
+1 Building the Agent
+====================
+
+First of all you'll need to add the following define
+to your local lwipopts.h:
+
+#define LWIP_SNMP               1
+
+and add the source files in lwip/src/core/snmp
+and some snmp headers in lwip/src/include/lwip to your makefile.
+
+Note you'll might need to adapt you network driver to update
+the mib2 variables for your interface.
+
+2 Running the Agent
+===================
+
+The following function calls must be made in your program to
+actually get the SNMP agent running.
+
+Before starting the agent you should supply pointers
+to non-volatile memory for sysContact, sysLocation,
+and snmpEnableAuthenTraps. You can do this by calling
+
+snmp_set_syscontact()
+snmp_set_syslocation()
+snmp_set_snmpenableauthentraps()
+
+Additionally you may want to set
+
+snmp_set_sysdescr()
+snmp_set_sysobjid() (if you have a private MIB)
+snmp_set_sysname()
+
+Also before starting the agent you need to setup
+one or more trap destinations using these calls:
+
+snmp_trap_dst_enable();
+snmp_trap_dst_ip_set();
+
+In the lwIP initialisation sequence call snmp_init() just after
+the call to udp_init().
+
+Exactly every 10 msec the SNMP uptime timestamp must be updated with
+snmp_inc_sysuptime(). You should call this from a timer interrupt
+or a timer signal handler depending on your runtime environment.
+
+An alternative way to update the SNMP uptime timestamp is to do a call like
+snmp_add_sysuptime(100) each 1000ms (which is bigger "step", but call to
+a lower frequency). Another one is to not call snmp_inc_sysuptime() or
+snmp_add_sysuptime(), and to define the SNMP_GET_SYSUPTIME(sysuptime) macro.
+This one is undefined by default in mib2.c. SNMP_GET_SYSUPTIME is called inside
+snmp_get_sysuptime(u32_t *value), and enable to change "sysuptime" value only
+when it's queried (any function which need "sysuptime" have to call
+snmp_get_sysuptime).
+
+
+3 Private MIBs
+==============
+
+If want to extend the agent with your own private MIB you'll need to
+add the following define to your local lwipopts.h:
+
+#define SNMP_PRIVATE_MIB        1
+
+You must provide the private_mib.h and associated files yourself.
+Note we don't have a "MIB compiler" that generates C source from a MIB,
+so you're required to do some serious coding if you enable this!
+
+Note the lwIP enterprise ID (26381) is assigned to the lwIP project,
+ALL OBJECT IDENTIFIERS LIVING UNDER THIS ID ARE ASSIGNED BY THE lwIP
+MAINTAINERS!
+
+If you need to create your own private MIB you'll need
+to apply for your own enterprise ID with IANA: http://www.iana.org/numbers.html 
+
+You can set it by passing a struct snmp_obj_id to the agent
+using snmp_set_sysobjid(&my_object_id), just before snmp_init().
+
+Note the object identifiers for thes MIB-2 and your private MIB
+tree must be kept in sorted ascending (lexicographical) order.
+This to ensure correct getnext operation.
+
+An example for a private MIB is part of the "minimal Unix" project:
+contrib/ports/unix/proj/minimal/lwip_prvmib.c
+
+The next chapter gives a more detailed description of the
+MIB-2 tree and the optional private MIB.
+
+4 The Gory Details
+==================
+
+4.0 Object identifiers and the MIB tree.
+
+We have three distinct parts for all object identifiers:
+
+The prefix
+  .iso.org.dod.internet
+
+the middle part 
+  .mgmt.mib-2.ip.ipNetToMediaTable.ipNetToMediaEntry.ipNetToMediaPhysAddress
+
+and the index part
+  .1.192.168.0.1
+
+Objects located above the .internet hierarchy aren't supported.
+Currently only the .mgmt sub-tree is available and
+when the SNMP_PRIVATE_MIB is enabled the .private tree
+becomes available too.
+
+Object identifiers from incoming requests are checked
+for a matching prefix, middle part and index part
+or are expanded(*) for GetNext requests with short
+or inexisting names in the request.
+(* we call this "expansion" but this also
+resembles the "auto-completion" operation)
+
+The middle part is usually located in ROM (const)
+to preserve precious RAM on small microcontrollers.
+However RAM location is possible for a dynamically
+changing private tree.
+
+The index part is handled by functions which in
+turn use dynamically allocated index trees from RAM.
+These trees are updated by e.g. the etharp code
+when new entries are made or removed form the ARP cache.
+
+/** @todo more gory details */
diff --git a/core/lwip/doc/sys_arch.txt b/core/lwip/doc/sys_arch.txt
new file mode 100644
index 00000000..4eb93078
--- /dev/null
+++ b/core/lwip/doc/sys_arch.txt
@@ -0,0 +1,216 @@
+sys_arch interface for lwIP 0.6++
+
+Author: Adam Dunkels
+
+The operating system emulation layer provides a common interface
+between the lwIP code and the underlying operating system kernel. The
+general idea is that porting lwIP to new architectures requires only
+small changes to a few header files and a new sys_arch
+implementation. It is also possible to do a sys_arch implementation
+that does not rely on any underlying operating system.
+
+The sys_arch provides semaphores and mailboxes to lwIP. For the full
+lwIP functionality, multiple threads support can be implemented in the
+sys_arch, but this is not required for the basic lwIP
+functionality. Previous versions of lwIP required the sys_arch to
+implement timer scheduling as well but as of lwIP 0.5 this is
+implemented in a higher layer.
+
+In addition to the source file providing the functionality of sys_arch,
+the OS emulation layer must provide several header files defining
+macros used throughout lwip.  The files required and the macros they
+must define are listed below the sys_arch description.
+
+Semaphores can be either counting or binary - lwIP works with both
+kinds. Mailboxes are used for message passing and can be implemented
+either as a queue which allows multiple messages to be posted to a
+mailbox, or as a rendez-vous point where only one message can be
+posted at a time. lwIP works with both kinds, but the former type will
+be more efficient. A message in a mailbox is just a pointer, nothing
+more. 
+
+Semaphores are represented by the type "sys_sem_t" which is typedef'd
+in the sys_arch.h file. Mailboxes are equivalently represented by the
+type "sys_mbox_t". lwIP does not place any restrictions on how
+sys_sem_t or sys_mbox_t are represented internally.
+
+The following functions must be implemented by the sys_arch:
+
+- void sys_init(void)
+
+  Is called to initialize the sys_arch layer.
+
+- sys_sem_t sys_sem_new(u8_t count)
+
+  Creates and returns a new semaphore. The "count" argument specifies
+  the initial state of the semaphore.
+
+- void sys_sem_free(sys_sem_t sem)
+
+  Deallocates a semaphore.
+
+- void sys_sem_signal(sys_sem_t sem)
+
+  Signals a semaphore.
+
+- u32_t sys_arch_sem_wait(sys_sem_t sem, u32_t timeout)
+
+  Blocks the thread while waiting for the semaphore to be
+  signaled. If the "timeout" argument is non-zero, the thread should
+  only be blocked for the specified time (measured in
+  milliseconds). If the "timeout" argument is zero, the thread should be
+  blocked until the semaphore is signalled.
+
+  If the timeout argument is non-zero, the return value is the number of
+  milliseconds spent waiting for the semaphore to be signaled. If the
+  semaphore wasn't signaled within the specified time, the return value is
+  SYS_ARCH_TIMEOUT. If the thread didn't have to wait for the semaphore
+  (i.e., it was already signaled), the function may return zero.
+
+  Notice that lwIP implements a function with a similar name,
+  sys_sem_wait(), that uses the sys_arch_sem_wait() function.
+
+- sys_mbox_t sys_mbox_new(int size)
+
+  Creates an empty mailbox for maximum "size" elements. Elements stored
+  in mailboxes are pointers. You have to define macros "_MBOX_SIZE"
+  in your lwipopts.h, or ignore this parameter in your implementation
+  and use a default size.
+
+- void sys_mbox_free(sys_mbox_t mbox)
+
+  Deallocates a mailbox. If there are messages still present in the
+  mailbox when the mailbox is deallocated, it is an indication of a
+  programming error in lwIP and the developer should be notified.
+
+- void sys_mbox_post(sys_mbox_t mbox, void *msg)
+
+  Posts the "msg" to the mailbox. This function have to block until
+  the "msg" is really posted.
+
+- err_t sys_mbox_trypost(sys_mbox_t mbox, void *msg)
+
+  Try to post the "msg" to the mailbox. Returns ERR_MEM if this one
+  is full, else, ERR_OK if the "msg" is posted.
+
+- u32_t sys_arch_mbox_fetch(sys_mbox_t mbox, void **msg, u32_t timeout)
+
+  Blocks the thread until a message arrives in the mailbox, but does
+  not block the thread longer than "timeout" milliseconds (similar to
+  the sys_arch_sem_wait() function). If "timeout" is 0, the thread should
+  be blocked until a message arrives. The "msg" argument is a result
+  parameter that is set by the function (i.e., by doing "*msg =
+  ptr"). The "msg" parameter maybe NULL to indicate that the message
+  should be dropped.
+
+  The return values are the same as for the sys_arch_sem_wait() function:
+  Number of milliseconds spent waiting or SYS_ARCH_TIMEOUT if there was a
+  timeout.
+
+  Note that a function with a similar name, sys_mbox_fetch(), is
+  implemented by lwIP. 
+
+- u32_t sys_arch_mbox_tryfetch(sys_mbox_t mbox, void **msg)
+
+  This is similar to sys_arch_mbox_fetch, however if a message is not
+  present in the mailbox, it immediately returns with the code
+  SYS_MBOX_EMPTY. On success 0 is returned.
+
+  To allow for efficient implementations, this can be defined as a
+  function-like macro in sys_arch.h instead of a normal function. For
+  example, a naive implementation could be:
+    #define sys_arch_mbox_tryfetch(mbox,msg) \
+      sys_arch_mbox_fetch(mbox,msg,1)
+  although this would introduce unnecessary delays.
+  
+If threads are supported by the underlying operating system and if
+such functionality is needed in lwIP, the following function will have
+to be implemented as well:
+
+- sys_thread_t sys_thread_new(char *name, void (* thread)(void *arg), void *arg, int stacksize, int prio)
+
+  Starts a new thread named "name" with priority "prio" that will begin its
+  execution in the function "thread()". The "arg" argument will be passed as an
+  argument to the thread() function. The stack size to used for this thread is
+  the "stacksize" parameter. The id of the new thread is returned. Both the id
+  and the priority are system dependent.
+
+- sys_prot_t sys_arch_protect(void)
+
+  This optional function does a "fast" critical region protection and returns
+  the previous protection level. This function is only called during very short
+  critical regions. An embedded system which supports ISR-based drivers might
+  want to implement this function by disabling interrupts. Task-based systems
+  might want to implement this by using a mutex or disabling tasking. This
+  function should support recursive calls from the same task or interrupt. In
+  other words, sys_arch_protect() could be called while already protected. In
+  that case the return value indicates that it is already protected.
+
+  sys_arch_protect() is only required if your port is supporting an operating
+  system.
+
+- void sys_arch_unprotect(sys_prot_t pval)
+
+  This optional function does a "fast" set of critical region protection to the
+  value specified by pval. See the documentation for sys_arch_protect() for
+  more information. This function is only required if your port is supporting
+  an operating system.
+
+Note:
+
+Be carefull with using mem_malloc() in sys_arch. When malloc() refers to
+mem_malloc() you can run into a circular function call problem. In mem.c
+lwip_mem_init() tries to allcate a semaphore using mem_malloc, which of course
+can't be performed when sys_arch uses mem_malloc.
+
+-------------------------------------------------------------------------------
+Additional files required for the "OS support" emulation layer:
+-------------------------------------------------------------------------------
+
+cc.h       - Architecture environment, some compiler specific, some
+             environment specific (probably should move env stuff 
+             to sys_arch.h.)
+
+  Typedefs for the types used by lwip -
+    u8_t, s8_t, u16_t, s16_t, u32_t, s32_t, mem_ptr_t
+
+  Compiler hints for packing lwip's structures -
+    PACK_STRUCT_FIELD(x)
+    PACK_STRUCT_STRUCT
+    PACK_STRUCT_BEGIN
+    PACK_STRUCT_END
+
+  Platform specific diagnostic output -
+    LWIP_PLATFORM_DIAG(x)    - non-fatal, print a message.
+    LWIP_PLATFORM_ASSERT(x)  - fatal, print message and abandon execution.
+    Portability defines for printf formatters:
+    U16_F, S16_F, X16_F, U32_F, S32_F, X32_F, SZT_F
+
+  "lightweight" synchronization mechanisms -
+    SYS_ARCH_DECL_PROTECT(x) - declare a protection state variable.
+    SYS_ARCH_PROTECT(x)      - enter protection mode.
+    SYS_ARCH_UNPROTECT(x)    - leave protection mode.
+
+  If the compiler does not provide memset() this file must include a
+  definition of it, or include a file which defines it.
+
+  This file must either include a system-local <errno.h> which defines
+  the standard *nix error codes, or it should #define LWIP_PROVIDE_ERRNO
+  to make lwip/arch.h define the codes which are used throughout.
+
+
+perf.h     - Architecture specific performance measurement.
+  Measurement calls made throughout lwip, these can be defined to nothing.
+    PERF_START               - start measuring something.
+    PERF_STOP(x)             - stop measuring something, and record the result.
+
+sys_arch.h - Tied to sys_arch.c
+
+  Arch dependent types for the following objects:
+    sys_sem_t, sys_mbox_t, sys_thread_t,
+  And, optionally:
+    sys_prot_t
+
+  Defines to set vars of sys_mbox_t and sys_sem_t to NULL.
+    SYS_MBOX_NULL NULL
+    SYS_SEM_NULL NULL
diff --git a/core/lwip/src/FILES b/core/lwip/src/FILES
new file mode 100644
index 00000000..952aeabb
--- /dev/null
+++ b/core/lwip/src/FILES
@@ -0,0 +1,13 @@
+api/      - The code for the high-level wrapper API. Not needed if
+            you use the lowel-level call-back/raw API.
+
+core/     - The core of the TPC/IP stack; protocol implementations,
+            memory and buffer management, and the low-level raw API.
+
+include/  - lwIP include files.
+
+netif/    - Generic network interface device drivers are kept here,
+            as well as the ARP module.
+
+For more information on the various subdirectories, check the FILES
+file in each directory.
diff --git a/core/lwip/src/api/api_lib.c b/core/lwip/src/api/api_lib.c
new file mode 100644
index 00000000..b1a9e525
--- /dev/null
+++ b/core/lwip/src/api/api_lib.c
@@ -0,0 +1,740 @@
+/**
+ * @file
+ * Sequential API External module
+ *
+ */
+ 
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+/* This is the part of the API that is linked with
+   the application */
+
+#include "lwip/opt.h"
+
+#if LWIP_NETCONN /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/api.h"
+#include "lwip/tcpip.h"
+#include "lwip/memp.h"
+
+#include "lwip/ip.h"
+#include "lwip/raw.h"
+#include "lwip/udp.h"
+#include "lwip/tcp.h"
+
+#include <string.h>
+
+/**
+ * Create a new netconn (of a specific type) that has a callback function.
+ * The corresponding pcb is also created.
+ *
+ * @param t the type of 'connection' to create (@see enum netconn_type)
+ * @param proto the IP protocol for RAW IP pcbs
+ * @param callback a function to call on status changes (RX available, TX'ed)
+ * @return a newly allocated struct netconn or
+ *         NULL on memory error
+ */
+struct netconn*
+netconn_new_with_proto_and_callback(enum netconn_type t, u8_t proto, netconn_callback callback)
+{
+  struct netconn *conn;
+  struct api_msg msg;
+
+  conn = netconn_alloc(t, callback);
+  if (conn != NULL) {
+    msg.function = do_newconn;
+    msg.msg.msg.n.proto = proto;
+    msg.msg.conn = conn;
+    if (TCPIP_APIMSG(&msg) != ERR_OK) {
+      LWIP_ASSERT("freeing conn without freeing pcb", conn->pcb.tcp == NULL);
+      LWIP_ASSERT("conn has no op_completed", sys_sem_valid(&conn->op_completed));
+      LWIP_ASSERT("conn has no recvmbox", sys_mbox_valid(&conn->recvmbox));
+#if LWIP_TCP
+      LWIP_ASSERT("conn->acceptmbox shouldn't exist", !sys_mbox_valid(&conn->acceptmbox));
+#endif /* LWIP_TCP */
+      sys_sem_free(&conn->op_completed);
+      sys_mbox_free(&conn->recvmbox);
+      memp_free(MEMP_NETCONN, conn);
+      return NULL;
+    }
+  }
+  return conn;
+}
+
+/**
+ * Close a netconn 'connection' and free its resources.
+ * UDP and RAW connection are completely closed, TCP pcbs might still be in a waitstate
+ * after this returns.
+ *
+ * @param conn the netconn to delete
+ * @return ERR_OK if the connection was deleted
+ */
+err_t
+netconn_delete(struct netconn *conn)
+{
+  struct api_msg msg;
+
+  /* No ASSERT here because possible to get a (conn == NULL) if we got an accept error */
+  if (conn == NULL) {
+    return ERR_OK;
+  }
+
+  msg.function = do_delconn;
+  msg.msg.conn = conn;
+  tcpip_apimsg(&msg);
+
+  netconn_free(conn);
+
+  /* don't care for return value of do_delconn since it only calls void functions */
+
+  return ERR_OK;
+}
+
+/**
+ * Get the local or remote IP address and port of a netconn.
+ * For RAW netconns, this returns the protocol instead of a port!
+ *
+ * @param conn the netconn to query
+ * @param addr a pointer to which to save the IP address
+ * @param port a pointer to which to save the port (or protocol for RAW)
+ * @param local 1 to get the local IP address, 0 to get the remote one
+ * @return ERR_CONN for invalid connections
+ *         ERR_OK if the information was retrieved
+ */
+err_t
+netconn_getaddr(struct netconn *conn, ip_addr_t *addr, u16_t *port, u8_t local)
+{
+  struct api_msg msg;
+  err_t err;
+
+  LWIP_ERROR("netconn_getaddr: invalid conn", (conn != NULL), return ERR_ARG;);
+  LWIP_ERROR("netconn_getaddr: invalid addr", (addr != NULL), return ERR_ARG;);
+  LWIP_ERROR("netconn_getaddr: invalid port", (port != NULL), return ERR_ARG;);
+
+  msg.function = do_getaddr;
+  msg.msg.conn = conn;
+  msg.msg.msg.ad.ipaddr = addr;
+  msg.msg.msg.ad.port = port;
+  msg.msg.msg.ad.local = local;
+  err = TCPIP_APIMSG(&msg);
+
+  NETCONN_SET_SAFE_ERR(conn, err);
+  return err;
+}
+
+/**
+ * Bind a netconn to a specific local IP address and port.
+ * Binding one netconn twice might not always be checked correctly!
+ *
+ * @param conn the netconn to bind
+ * @param addr the local IP address to bind the netconn to (use IP_ADDR_ANY
+ *             to bind to all addresses)
+ * @param port the local port to bind the netconn to (not used for RAW)
+ * @return ERR_OK if bound, any other err_t on failure
+ */
+err_t
+netconn_bind(struct netconn *conn, ip_addr_t *addr, u16_t port)
+{
+  struct api_msg msg;
+  err_t err;
+
+  LWIP_ERROR("netconn_bind: invalid conn", (conn != NULL), return ERR_ARG;);
+
+  msg.function = do_bind;
+  msg.msg.conn = conn;
+  msg.msg.msg.bc.ipaddr = addr;
+  msg.msg.msg.bc.port = port;
+  err = TCPIP_APIMSG(&msg);
+
+  NETCONN_SET_SAFE_ERR(conn, err);
+  return err;
+}
+
+/**
+ * Connect a netconn to a specific remote IP address and port.
+ *
+ * @param conn the netconn to connect
+ * @param addr the remote IP address to connect to
+ * @param port the remote port to connect to (no used for RAW)
+ * @return ERR_OK if connected, return value of tcp_/udp_/raw_connect otherwise
+ */
+err_t
+netconn_connect(struct netconn *conn, ip_addr_t *addr, u16_t port)
+{
+  struct api_msg msg;
+  err_t err;
+
+  LWIP_ERROR("netconn_connect: invalid conn", (conn != NULL), return ERR_ARG;);
+
+  msg.function = do_connect;
+  msg.msg.conn = conn;
+  msg.msg.msg.bc.ipaddr = addr;
+  msg.msg.msg.bc.port = port;
+  /* This is the only function which need to not block tcpip_thread */
+  err = tcpip_apimsg(&msg);
+
+  NETCONN_SET_SAFE_ERR(conn, err);
+  return err;
+}
+
+/**
+ * Disconnect a netconn from its current peer (only valid for UDP netconns).
+ *
+ * @param conn the netconn to disconnect
+ * @return TODO: return value is not set here...
+ */
+err_t
+netconn_disconnect(struct netconn *conn)
+{
+  struct api_msg msg;
+  err_t err;
+
+  LWIP_ERROR("netconn_disconnect: invalid conn", (conn != NULL), return ERR_ARG;);
+
+  msg.function = do_disconnect;
+  msg.msg.conn = conn;
+  err = TCPIP_APIMSG(&msg);
+
+  NETCONN_SET_SAFE_ERR(conn, err);
+  return err;
+}
+
+/**
+ * Set a TCP netconn into listen mode
+ *
+ * @param conn the tcp netconn to set to listen mode
+ * @param backlog the listen backlog, only used if TCP_LISTEN_BACKLOG==1
+ * @return ERR_OK if the netconn was set to listen (UDP and RAW netconns
+ *         don't return any error (yet?))
+ */
+err_t
+netconn_listen_with_backlog(struct netconn *conn, u8_t backlog)
+{
+#if LWIP_TCP
+  struct api_msg msg;
+  err_t err;
+
+  /* This does no harm. If TCP_LISTEN_BACKLOG is off, backlog is unused. */
+  LWIP_UNUSED_ARG(backlog);
+
+  LWIP_ERROR("netconn_listen: invalid conn", (conn != NULL), return ERR_ARG;);
+
+  msg.function = do_listen;
+  msg.msg.conn = conn;
+#if TCP_LISTEN_BACKLOG
+  msg.msg.msg.lb.backlog = backlog;
+#endif /* TCP_LISTEN_BACKLOG */
+  err = TCPIP_APIMSG(&msg);
+
+  NETCONN_SET_SAFE_ERR(conn, err);
+  return err;
+#else /* LWIP_TCP */
+  LWIP_UNUSED_ARG(conn);
+  LWIP_UNUSED_ARG(backlog);
+  return ERR_ARG;
+#endif /* LWIP_TCP */
+}
+
+/**
+ * Accept a new connection on a TCP listening netconn.
+ *
+ * @param conn the TCP listen netconn
+ * @param new_conn pointer where the new connection is stored
+ * @return ERR_OK if a new connection has been received or an error
+ *                code otherwise
+ */
+err_t
+netconn_accept(struct netconn *conn, struct netconn **new_conn)
+{
+#if LWIP_TCP
+  struct netconn *newconn;
+  err_t err;
+#if TCP_LISTEN_BACKLOG
+  struct api_msg msg;
+#endif /* TCP_LISTEN_BACKLOG */
+
+  LWIP_ERROR("netconn_accept: invalid pointer",    (new_conn != NULL),                  return ERR_ARG;);
+  *new_conn = NULL;
+  LWIP_ERROR("netconn_accept: invalid conn",       (conn != NULL),                      return ERR_ARG;);
+  LWIP_ERROR("netconn_accept: invalid acceptmbox", sys_mbox_valid(&conn->acceptmbox),   return ERR_ARG;);
+
+  err = conn->last_err;
+  if (ERR_IS_FATAL(err)) {
+    /* don't recv on fatal errors: this might block the application task
+       waiting on acceptmbox forever! */
+    return err;
+  }
+
+#if LWIP_SO_RCVTIMEO
+  if (sys_arch_mbox_fetch(&conn->acceptmbox, (void **)&newconn, conn->recv_timeout) == SYS_ARCH_TIMEOUT) {
+    NETCONN_SET_SAFE_ERR(conn, ERR_TIMEOUT);
+    return ERR_TIMEOUT;
+  }
+#else
+  sys_arch_mbox_fetch(&conn->acceptmbox, (void **)&newconn, 0);
+#endif /* LWIP_SO_RCVTIMEO*/
+  /* Register event with callback */
+  API_EVENT(conn, NETCONN_EVT_RCVMINUS, 0);
+
+  if (newconn == NULL) {
+    /* connection has been aborted */
+    NETCONN_SET_SAFE_ERR(conn, ERR_ABRT);
+    return ERR_ABRT;
+  }
+#if TCP_LISTEN_BACKLOG
+  /* Let the stack know that we have accepted the connection. */
+  msg.function = do_recv;
+  msg.msg.conn = conn;
+  /* don't care for the return value of do_recv */
+  TCPIP_APIMSG(&msg);
+#endif /* TCP_LISTEN_BACKLOG */
+
+  *new_conn = newconn;
+  /* don't set conn->last_err: it's only ERR_OK, anyway */
+  return ERR_OK;
+#else /* LWIP_TCP */
+  LWIP_UNUSED_ARG(conn);
+  LWIP_UNUSED_ARG(new_conn);
+  return ERR_ARG;
+#endif /* LWIP_TCP */
+}
+
+/**
+ * Receive data: actual implementation that doesn't care whether pbuf or netbuf
+ * is received
+ *
+ * @param conn the netconn from which to receive data
+ * @param new_buf pointer where a new pbuf/netbuf is stored when received data
+ * @return ERR_OK if data has been received, an error code otherwise (timeout,
+ *                memory error or another error)
+ */
+static err_t
+netconn_recv_data(struct netconn *conn, void **new_buf)
+{
+  void *buf = NULL;
+  u16_t len;
+  err_t err;
+#if LWIP_TCP
+  struct api_msg msg;
+#endif /* LWIP_TCP */
+
+  LWIP_ERROR("netconn_recv: invalid pointer", (new_buf != NULL), return ERR_ARG;);
+  *new_buf = NULL;
+  LWIP_ERROR("netconn_recv: invalid conn",    (conn != NULL),    return ERR_ARG;);
+  LWIP_ERROR("netconn_accept: invalid recvmbox", sys_mbox_valid(&conn->recvmbox), return ERR_CONN;);
+
+  err = conn->last_err;
+  if (ERR_IS_FATAL(err)) {
+    /* don't recv on fatal errors: this might block the application task
+       waiting on recvmbox forever! */
+    /* @todo: this does not allow us to fetch data that has been put into recvmbox
+       before the fatal error occurred - is that a problem? */
+    return err;
+  }
+
+#if LWIP_SO_RCVTIMEO
+  if (sys_arch_mbox_fetch(&conn->recvmbox, &buf, conn->recv_timeout) == SYS_ARCH_TIMEOUT) {
+    NETCONN_SET_SAFE_ERR(conn, ERR_TIMEOUT);
+    return ERR_TIMEOUT;
+  }
+#else
+  sys_arch_mbox_fetch(&conn->recvmbox, &buf, 0);
+#endif /* LWIP_SO_RCVTIMEO*/
+
+#if LWIP_TCP
+  if (conn->type == NETCONN_TCP) {
+    if (!netconn_get_noautorecved(conn) || (buf == NULL)) {
+      /* Let the stack know that we have taken the data. */
+      /* TODO: Speedup: Don't block and wait for the answer here
+         (to prevent multiple thread-switches). */
+      msg.function = do_recv;
+      msg.msg.conn = conn;
+      if (buf != NULL) {
+        msg.msg.msg.r.len = ((struct pbuf *)buf)->tot_len;
+      } else {
+        msg.msg.msg.r.len = 1;
+      }
+      /* don't care for the return value of do_recv */
+      TCPIP_APIMSG(&msg);
+    }
+
+    /* If we are closed, we indicate that we no longer wish to use the socket */
+    if (buf == NULL) {
+      API_EVENT(conn, NETCONN_EVT_RCVMINUS, 0);
+      /* Avoid to lose any previous error code */
+      NETCONN_SET_SAFE_ERR(conn, ERR_CLSD);
+      return ERR_CLSD;
+    }
+    len = ((struct pbuf *)buf)->tot_len;
+  }
+#endif /* LWIP_TCP */
+#if LWIP_TCP && (LWIP_UDP || LWIP_RAW)
+  else
+#endif /* LWIP_TCP && (LWIP_UDP || LWIP_RAW) */
+#if (LWIP_UDP || LWIP_RAW)
+  {
+    LWIP_ASSERT("buf != NULL", buf != NULL);
+    len = netbuf_len((struct netbuf *)buf);
+  }
+#endif /* (LWIP_UDP || LWIP_RAW) */
+
+#if LWIP_SO_RCVBUF
+  SYS_ARCH_DEC(conn->recv_avail, len);
+#endif /* LWIP_SO_RCVBUF */
+  /* Register event with callback */
+  API_EVENT(conn, NETCONN_EVT_RCVMINUS, len);
+
+  LWIP_DEBUGF(API_LIB_DEBUG, ("netconn_recv_data: received %p, len=%"U16_F"\n", buf, len));
+
+  *new_buf = buf;
+  /* don't set conn->last_err: it's only ERR_OK, anyway */
+  return ERR_OK;
+}
+
+/**
+ * Receive data (in form of a pbuf) from a TCP netconn
+ *
+ * @param conn the netconn from which to receive data
+ * @param new_buf pointer where a new pbuf is stored when received data
+ * @return ERR_OK if data has been received, an error code otherwise (timeout,
+ *                memory error or another error)
+ *         ERR_ARG if conn is not a TCP netconn
+ */
+err_t
+netconn_recv_tcp_pbuf(struct netconn *conn, struct pbuf **new_buf)
+{
+  LWIP_ERROR("netconn_recv: invalid conn", (conn != NULL) &&
+             netconn_type(conn) == NETCONN_TCP, return ERR_ARG;);
+
+  return netconn_recv_data(conn, (void **)new_buf);
+}
+
+/**
+ * Receive data (in form of a netbuf containing a packet buffer) from a netconn
+ *
+ * @param conn the netconn from which to receive data
+ * @param new_buf pointer where a new netbuf is stored when received data
+ * @return ERR_OK if data has been received, an error code otherwise (timeout,
+ *                memory error or another error)
+ */
+err_t
+netconn_recv(struct netconn *conn, struct netbuf **new_buf)
+{
+#if LWIP_TCP
+  struct netbuf *buf = NULL;
+  err_t err;
+#endif /* LWIP_TCP */
+
+  LWIP_ERROR("netconn_recv: invalid pointer", (new_buf != NULL), return ERR_ARG;);
+  *new_buf = NULL;
+  LWIP_ERROR("netconn_recv: invalid conn",    (conn != NULL),    return ERR_ARG;);
+  LWIP_ERROR("netconn_accept: invalid recvmbox", sys_mbox_valid(&conn->recvmbox), return ERR_CONN;);
+
+#if LWIP_TCP
+  if (conn->type == NETCONN_TCP) {
+    struct pbuf *p = NULL;
+    /* This is not a listening netconn, since recvmbox is set */
+
+    buf = (struct netbuf *)memp_malloc(MEMP_NETBUF);
+    if (buf == NULL) {
+      NETCONN_SET_SAFE_ERR(conn, ERR_MEM);
+      return ERR_MEM;
+    }
+
+    err = netconn_recv_data(conn, (void **)&p);
+    if (err != ERR_OK) {
+      memp_free(MEMP_NETBUF, buf);
+      return err;
+    }
+    LWIP_ASSERT("p != NULL", p != NULL);
+
+    buf->p = p;
+    buf->ptr = p;
+    buf->port = 0;
+    ip_addr_set_any(&buf->addr);
+    *new_buf = buf;
+    /* don't set conn->last_err: it's only ERR_OK, anyway */
+    return ERR_OK;
+  } else
+#endif /* LWIP_TCP */
+  {
+#if (LWIP_UDP || LWIP_RAW)
+    return netconn_recv_data(conn, (void **)new_buf);
+#endif /* (LWIP_UDP || LWIP_RAW) */
+  }
+}
+
+/**
+ * TCP: update the receive window: by calling this, the application
+ * tells the stack that it has processed data and is able to accept
+ * new data.
+ * ATTENTION: use with care, this is mainly used for sockets!
+ * Can only be used when calling netconn_set_noautorecved(conn, 1) before.
+ *
+ * @param conn the netconn for which to update the receive window
+ * @param length amount of data processed (ATTENTION: this must be accurate!)
+ */
+void
+netconn_recved(struct netconn *conn, u32_t length)
+{
+#if LWIP_TCP
+  if ((conn != NULL) && (conn->type == NETCONN_TCP) &&
+      (netconn_get_noautorecved(conn))) {
+    struct api_msg msg;
+    /* Let the stack know that we have taken the data. */
+    /* TODO: Speedup: Don't block and wait for the answer here
+       (to prevent multiple thread-switches). */
+    msg.function = do_recv;
+    msg.msg.conn = conn;
+    msg.msg.msg.r.len = length;
+    /* don't care for the return value of do_recv */
+    TCPIP_APIMSG(&msg);
+  }
+#else /* LWIP_TCP */
+  LWIP_UNUSED_ARG(conn);
+  LWIP_UNUSED_ARG(length);
+#endif /* LWIP_TCP */
+}
+
+/**
+ * Send data (in form of a netbuf) to a specific remote IP address and port.
+ * Only to be used for UDP and RAW netconns (not TCP).
+ *
+ * @param conn the netconn over which to send data
+ * @param buf a netbuf containing the data to send
+ * @param addr the remote IP address to which to send the data
+ * @param port the remote port to which to send the data
+ * @return ERR_OK if data was sent, any other err_t on error
+ */
+err_t
+netconn_sendto(struct netconn *conn, struct netbuf *buf, ip_addr_t *addr, u16_t port)
+{
+  if (buf != NULL) {
+    ip_addr_set(&buf->addr, addr);
+    buf->port = port;
+    return netconn_send(conn, buf);
+  }
+  return ERR_VAL;
+}
+
+/**
+ * Send data over a UDP or RAW netconn (that is already connected).
+ *
+ * @param conn the UDP or RAW netconn over which to send data
+ * @param buf a netbuf containing the data to send
+ * @return ERR_OK if data was sent, any other err_t on error
+ */
+err_t
+netconn_send(struct netconn *conn, struct netbuf *buf)
+{
+  struct api_msg msg;
+  err_t err;
+
+  LWIP_ERROR("netconn_send: invalid conn",  (conn != NULL), return ERR_ARG;);
+
+  LWIP_DEBUGF(API_LIB_DEBUG, ("netconn_send: sending %"U16_F" bytes\n", buf->p->tot_len));
+  msg.function = do_send;
+  msg.msg.conn = conn;
+  msg.msg.msg.b = buf;
+  err = TCPIP_APIMSG(&msg);
+
+  NETCONN_SET_SAFE_ERR(conn, err);
+  return err;
+}
+
+/**
+ * Send data over a TCP netconn.
+ *
+ * @param conn the TCP netconn over which to send data
+ * @param dataptr pointer to the application buffer that contains the data to send
+ * @param size size of the application data to send
+ * @param apiflags combination of following flags :
+ * - NETCONN_COPY: data will be copied into memory belonging to the stack
+ * - NETCONN_MORE: for TCP connection, PSH flag will be set on last segment sent
+ * - NETCONN_DONTBLOCK: only write the data if all dat can be written at once
+ * @return ERR_OK if data was sent, any other err_t on error
+ */
+err_t
+netconn_write(struct netconn *conn, const void *dataptr, size_t size, u8_t apiflags)
+{
+  struct api_msg msg;
+  err_t err;
+
+  LWIP_ERROR("netconn_write: invalid conn",  (conn != NULL), return ERR_ARG;);
+  LWIP_ERROR("netconn_write: invalid conn->type",  (conn->type == NETCONN_TCP), return ERR_VAL;);
+  if (size == 0) {
+    return ERR_OK;
+  }
+
+  /* @todo: for non-blocking write, check if 'size' would ever fit into
+            snd_queue or snd_buf */
+  msg.function = do_write;
+  msg.msg.conn = conn;
+  msg.msg.msg.w.dataptr = dataptr;
+  msg.msg.msg.w.apiflags = apiflags;
+  msg.msg.msg.w.len = size;
+  /* For locking the core: this _can_ be delayed on low memory/low send buffer,
+     but if it is, this is done inside api_msg.c:do_write(), so we can use the
+     non-blocking version here. */
+  err = TCPIP_APIMSG(&msg);
+
+  NETCONN_SET_SAFE_ERR(conn, err);
+  return err;
+}
+
+/**
+ * Close ot shutdown a TCP netconn (doesn't delete it).
+ *
+ * @param conn the TCP netconn to close or shutdown
+ * @param how fully close or only shutdown one side?
+ * @return ERR_OK if the netconn was closed, any other err_t on error
+ */
+static err_t
+netconn_close_shutdown(struct netconn *conn, u8_t how)
+{
+  struct api_msg msg;
+  err_t err;
+
+  LWIP_ERROR("netconn_close: invalid conn",  (conn != NULL), return ERR_ARG;);
+
+  msg.function = do_close;
+  msg.msg.conn = conn;
+  /* shutting down both ends is the same as closing */
+  msg.msg.msg.sd.shut = how;
+  /* because of the LWIP_TCPIP_CORE_LOCKING implementation of do_close,
+     don't use TCPIP_APIMSG here */
+  err = tcpip_apimsg(&msg);
+
+  NETCONN_SET_SAFE_ERR(conn, err);
+  return err;
+}
+
+/**
+ * Close a TCP netconn (doesn't delete it).
+ *
+ * @param conn the TCP netconn to close
+ * @return ERR_OK if the netconn was closed, any other err_t on error
+ */
+err_t
+netconn_close(struct netconn *conn)
+{
+  /* shutting down both ends is the same as closing */
+  return netconn_close_shutdown(conn, NETCONN_SHUT_RDWR);
+}
+
+/**
+ * Shut down one or both sides of a TCP netconn (doesn't delete it).
+ *
+ * @param conn the TCP netconn to shut down
+ * @return ERR_OK if the netconn was closed, any other err_t on error
+ */
+err_t
+netconn_shutdown(struct netconn *conn, u8_t shut_rx, u8_t shut_tx)
+{
+  return netconn_close_shutdown(conn, (shut_rx ? NETCONN_SHUT_RD : 0) | (shut_tx ? NETCONN_SHUT_WR : 0));
+}
+
+#if LWIP_IGMP
+/**
+ * Join multicast groups for UDP netconns.
+ *
+ * @param conn the UDP netconn for which to change multicast addresses
+ * @param multiaddr IP address of the multicast group to join or leave
+ * @param netif_addr the IP address of the network interface on which to send
+ *                  the igmp message
+ * @param join_or_leave flag whether to send a join- or leave-message
+ * @return ERR_OK if the action was taken, any err_t on error
+ */
+err_t
+netconn_join_leave_group(struct netconn *conn,
+                         ip_addr_t *multiaddr,
+                         ip_addr_t *netif_addr,
+                         enum netconn_igmp join_or_leave)
+{
+  struct api_msg msg;
+  err_t err;
+
+  LWIP_ERROR("netconn_join_leave_group: invalid conn",  (conn != NULL), return ERR_ARG;);
+
+  msg.function = do_join_leave_group;
+  msg.msg.conn = conn;
+  msg.msg.msg.jl.multiaddr = multiaddr;
+  msg.msg.msg.jl.netif_addr = netif_addr;
+  msg.msg.msg.jl.join_or_leave = join_or_leave;
+  err = TCPIP_APIMSG(&msg);
+
+  NETCONN_SET_SAFE_ERR(conn, err);
+  return err;
+}
+#endif /* LWIP_IGMP */
+
+#if LWIP_DNS
+/**
+ * Execute a DNS query, only one IP address is returned
+ *
+ * @param name a string representation of the DNS host name to query
+ * @param addr a preallocated ip_addr_t where to store the resolved IP address
+ * @return ERR_OK: resolving succeeded
+ *         ERR_MEM: memory error, try again later
+ *         ERR_ARG: dns client not initialized or invalid hostname
+ *         ERR_VAL: dns server response was invalid
+ */
+err_t
+netconn_gethostbyname(const char *name, ip_addr_t *addr)
+{
+  struct dns_api_msg msg;
+  err_t err;
+  sys_sem_t sem;
+
+  LWIP_ERROR("netconn_gethostbyname: invalid name", (name != NULL), return ERR_ARG;);
+  LWIP_ERROR("netconn_gethostbyname: invalid addr", (addr != NULL), return ERR_ARG;);
+
+  err = sys_sem_new(&sem, 0);
+  if (err != ERR_OK) {
+    return err;
+  }
+
+  msg.name = name;
+  msg.addr = addr;
+  msg.err = &err;
+  msg.sem = &sem;
+
+  tcpip_callback(do_gethostbyname, &msg);
+  sys_sem_wait(&sem);
+  sys_sem_free(&sem);
+
+  return err;
+}
+#endif /* LWIP_DNS*/
+
+#endif /* LWIP_NETCONN */
diff --git a/core/lwip/src/api/api_msg.c b/core/lwip/src/api/api_msg.c
new file mode 100644
index 00000000..448f96dd
--- /dev/null
+++ b/core/lwip/src/api/api_msg.c
@@ -0,0 +1,1535 @@
+/**
+ * @file
+ * Sequential API Internal module
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_NETCONN /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/api_msg.h"
+
+#include "lwip/ip.h"
+#include "lwip/udp.h"
+#include "lwip/tcp.h"
+#include "lwip/raw.h"
+
+#include "lwip/memp.h"
+#include "lwip/tcpip.h"
+#include "lwip/igmp.h"
+#include "lwip/dns.h"
+
+#include <string.h>
+
+#define SET_NONBLOCKING_CONNECT(conn, val)  do { if(val) { \
+  (conn)->flags |= NETCONN_FLAG_IN_NONBLOCKING_CONNECT; \
+} else { \
+  (conn)->flags &= ~ NETCONN_FLAG_IN_NONBLOCKING_CONNECT; }} while(0)
+#define IN_NONBLOCKING_CONNECT(conn) (((conn)->flags & NETCONN_FLAG_IN_NONBLOCKING_CONNECT) != 0)
+
+/* forward declarations */
+#if LWIP_TCP
+static err_t do_writemore(struct netconn *conn);
+static void do_close_internal(struct netconn *conn);
+#endif
+
+#if LWIP_RAW
+/**
+ * Receive callback function for RAW netconns.
+ * Doesn't 'eat' the packet, only references it and sends it to
+ * conn->recvmbox
+ *
+ * @see raw.h (struct raw_pcb.recv) for parameters and return value
+ */
+static u8_t
+recv_raw(void *arg, struct raw_pcb *pcb, struct pbuf *p,
+    ip_addr_t *addr)
+{
+  struct pbuf *q;
+  struct netbuf *buf;
+  struct netconn *conn;
+
+  LWIP_UNUSED_ARG(addr);
+  conn = (struct netconn *)arg;
+
+  if ((conn != NULL) && sys_mbox_valid(&conn->recvmbox)) {
+#if LWIP_SO_RCVBUF
+    int recv_avail;
+    SYS_ARCH_GET(conn->recv_avail, recv_avail);
+    if ((recv_avail + (int)(p->tot_len)) > conn->recv_bufsize) {
+      return 0;
+    }
+#endif /* LWIP_SO_RCVBUF */
+    /* copy the whole packet into new pbufs */
+    q = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_RAM);
+    if(q != NULL) {
+      if (pbuf_copy(q, p) != ERR_OK) {
+        pbuf_free(q);
+        q = NULL;
+      }
+    }
+
+    if (q != NULL) {
+      u16_t len;
+      buf = (struct netbuf *)memp_malloc(MEMP_NETBUF);
+      if (buf == NULL) {
+        pbuf_free(q);
+        return 0;
+      }
+
+      buf->p = q;
+      buf->ptr = q;
+      ip_addr_copy(buf->addr, *ip_current_src_addr());
+      buf->port = pcb->protocol;
+
+      len = q->tot_len;
+      if (sys_mbox_trypost(&conn->recvmbox, buf) != ERR_OK) {
+        netbuf_delete(buf);
+        return 0;
+      } else {
+#if LWIP_SO_RCVBUF
+        SYS_ARCH_INC(conn->recv_avail, len);
+#endif /* LWIP_SO_RCVBUF */
+        /* Register event with callback */
+        API_EVENT(conn, NETCONN_EVT_RCVPLUS, len);
+      }
+    }
+  }
+
+  return 0; /* do not eat the packet */
+}
+#endif /* LWIP_RAW*/
+
+#if LWIP_UDP
+/**
+ * Receive callback function for UDP netconns.
+ * Posts the packet to conn->recvmbox or deletes it on memory error.
+ *
+ * @see udp.h (struct udp_pcb.recv) for parameters
+ */
+static void
+recv_udp(void *arg, struct udp_pcb *pcb, struct pbuf *p,
+   ip_addr_t *addr, u16_t port)
+{
+  struct netbuf *buf;
+  struct netconn *conn;
+  u16_t len;
+#if LWIP_SO_RCVBUF
+  int recv_avail;
+#endif /* LWIP_SO_RCVBUF */
+
+  LWIP_UNUSED_ARG(pcb); /* only used for asserts... */
+  LWIP_ASSERT("recv_udp must have a pcb argument", pcb != NULL);
+  LWIP_ASSERT("recv_udp must have an argument", arg != NULL);
+  conn = (struct netconn *)arg;
+  LWIP_ASSERT("recv_udp: recv for wrong pcb!", conn->pcb.udp == pcb);
+
+#if LWIP_SO_RCVBUF
+  SYS_ARCH_GET(conn->recv_avail, recv_avail);
+  if ((conn == NULL) || !sys_mbox_valid(&conn->recvmbox) ||
+      ((recv_avail + (int)(p->tot_len)) > conn->recv_bufsize)) {
+#else  /* LWIP_SO_RCVBUF */
+  if ((conn == NULL) || !sys_mbox_valid(&conn->recvmbox)) {
+#endif /* LWIP_SO_RCVBUF */
+    pbuf_free(p);
+    return;
+  }
+
+  buf = (struct netbuf *)memp_malloc(MEMP_NETBUF);
+  if (buf == NULL) {
+    pbuf_free(p);
+    return;
+  } else {
+    buf->p = p;
+    buf->ptr = p;
+    ip_addr_set(&buf->addr, addr);
+    buf->port = port;
+#if LWIP_NETBUF_RECVINFO
+    {
+      const struct ip_hdr* iphdr = ip_current_header();
+      /* get the UDP header - always in the first pbuf, ensured by udp_input */
+      const struct udp_hdr* udphdr = (void*)(((char*)iphdr) + IPH_LEN(iphdr));
+#if LWIP_CHECKSUM_ON_COPY
+      buf->flags = NETBUF_FLAG_DESTADDR;
+#endif /* LWIP_CHECKSUM_ON_COPY */
+      ip_addr_set(&buf->toaddr, ip_current_dest_addr());
+      buf->toport_chksum = udphdr->dest;
+    }
+#endif /* LWIP_NETBUF_RECVINFO */
+  }
+
+  len = p->tot_len;
+  if (sys_mbox_trypost(&conn->recvmbox, buf) != ERR_OK) {
+    netbuf_delete(buf);
+    return;
+  } else {
+#if LWIP_SO_RCVBUF
+    SYS_ARCH_INC(conn->recv_avail, len);
+#endif /* LWIP_SO_RCVBUF */
+    /* Register event with callback */
+    API_EVENT(conn, NETCONN_EVT_RCVPLUS, len);
+  }
+}
+#endif /* LWIP_UDP */
+
+#if LWIP_TCP
+/**
+ * Receive callback function for TCP netconns.
+ * Posts the packet to conn->recvmbox, but doesn't delete it on errors.
+ *
+ * @see tcp.h (struct tcp_pcb.recv) for parameters and return value
+ */
+static err_t
+recv_tcp(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
+{
+  struct netconn *conn;
+  u16_t len;
+
+  LWIP_UNUSED_ARG(pcb);
+  LWIP_ASSERT("recv_tcp must have a pcb argument", pcb != NULL);
+  LWIP_ASSERT("recv_tcp must have an argument", arg != NULL);
+  conn = (struct netconn *)arg;
+  LWIP_ASSERT("recv_tcp: recv for wrong pcb!", conn->pcb.tcp == pcb);
+
+  if (conn == NULL) {
+    return ERR_VAL;
+  }
+  if (!sys_mbox_valid(&conn->recvmbox)) {
+    /* recvmbox already deleted */
+    if (p != NULL) {
+      tcp_recved(pcb, p->tot_len);
+      pbuf_free(p);
+    }
+    return ERR_OK;
+  }
+  /* Unlike for UDP or RAW pcbs, don't check for available space
+     using recv_avail since that could break the connection
+     (data is already ACKed) */
+
+  /* don't overwrite fatal errors! */
+  NETCONN_SET_SAFE_ERR(conn, err);
+
+  if (p != NULL) {
+    len = p->tot_len;
+  } else {
+    len = 0;
+  }
+
+  if (sys_mbox_trypost(&conn->recvmbox, p) != ERR_OK) {
+    /* don't deallocate p: it is presented to us later again from tcp_fasttmr! */
+    return ERR_MEM;
+  } else {
+#if LWIP_SO_RCVBUF
+    SYS_ARCH_INC(conn->recv_avail, len);
+#endif /* LWIP_SO_RCVBUF */
+    /* Register event with callback */
+    API_EVENT(conn, NETCONN_EVT_RCVPLUS, len);
+  }
+
+  return ERR_OK;
+}
+
+/**
+ * Poll callback function for TCP netconns.
+ * Wakes up an application thread that waits for a connection to close
+ * or data to be sent. The application thread then takes the
+ * appropriate action to go on.
+ *
+ * Signals the conn->sem.
+ * netconn_close waits for conn->sem if closing failed.
+ *
+ * @see tcp.h (struct tcp_pcb.poll) for parameters and return value
+ */
+static err_t
+poll_tcp(void *arg, struct tcp_pcb *pcb)
+{
+  struct netconn *conn = (struct netconn *)arg;
+
+  LWIP_UNUSED_ARG(pcb);
+  LWIP_ASSERT("conn != NULL", (conn != NULL));
+
+  if (conn->state == NETCONN_WRITE) {
+    do_writemore(conn);
+  } else if (conn->state == NETCONN_CLOSE) {
+    do_close_internal(conn);
+  }
+  /* @todo: implement connect timeout here? */
+
+  /* Did a nonblocking write fail before? Then check available write-space. */
+  if (conn->flags & NETCONN_FLAG_CHECK_WRITESPACE) {
+    /* If the queued byte- or pbuf-count drops below the configured low-water limit,
+       let select mark this pcb as writable again. */
+    if ((conn->pcb.tcp != NULL) && (tcp_sndbuf(conn->pcb.tcp) > TCP_SNDLOWAT) &&
+      (tcp_sndqueuelen(conn->pcb.tcp) < TCP_SNDQUEUELOWAT)) {
+      conn->flags &= ~NETCONN_FLAG_CHECK_WRITESPACE;
+      API_EVENT(conn, NETCONN_EVT_SENDPLUS, 0);
+    }
+  }
+
+  return ERR_OK;
+}
+
+/**
+ * Sent callback function for TCP netconns.
+ * Signals the conn->sem and calls API_EVENT.
+ * netconn_write waits for conn->sem if send buffer is low.
+ *
+ * @see tcp.h (struct tcp_pcb.sent) for parameters and return value
+ */
+static err_t
+sent_tcp(void *arg, struct tcp_pcb *pcb, u16_t len)
+{
+  struct netconn *conn = (struct netconn *)arg;
+
+  LWIP_UNUSED_ARG(pcb);
+  LWIP_ASSERT("conn != NULL", (conn != NULL));
+
+  if (conn->state == NETCONN_WRITE) {
+    do_writemore(conn);
+  } else if (conn->state == NETCONN_CLOSE) {
+    do_close_internal(conn);
+  }
+
+  if (conn) {
+    /* If the queued byte- or pbuf-count drops below the configured low-water limit,
+       let select mark this pcb as writable again. */
+    if ((conn->pcb.tcp != NULL) && (tcp_sndbuf(conn->pcb.tcp) > TCP_SNDLOWAT) &&
+      (tcp_sndqueuelen(conn->pcb.tcp) < TCP_SNDQUEUELOWAT)) {
+      conn->flags &= ~NETCONN_FLAG_CHECK_WRITESPACE;
+      API_EVENT(conn, NETCONN_EVT_SENDPLUS, len);
+    }
+  }
+  
+  return ERR_OK;
+}
+
+/**
+ * Error callback function for TCP netconns.
+ * Signals conn->sem, posts to all conn mboxes and calls API_EVENT.
+ * The application thread has then to decide what to do.
+ *
+ * @see tcp.h (struct tcp_pcb.err) for parameters
+ */
+static void
+err_tcp(void *arg, err_t err)
+{
+  struct netconn *conn;
+  enum netconn_state old_state;
+  SYS_ARCH_DECL_PROTECT(lev);
+
+  conn = (struct netconn *)arg;
+  LWIP_ASSERT("conn != NULL", (conn != NULL));
+
+  conn->pcb.tcp = NULL;
+
+  /* no check since this is always fatal! */
+  SYS_ARCH_PROTECT(lev);
+  conn->last_err = err;
+  SYS_ARCH_UNPROTECT(lev);
+
+  /* reset conn->state now before waking up other threads */
+  old_state = conn->state;
+  conn->state = NETCONN_NONE;
+
+  /* Notify the user layer about a connection error. Used to signal
+     select. */
+  API_EVENT(conn, NETCONN_EVT_ERROR, 0);
+  /* Try to release selects pending on 'read' or 'write', too.
+     They will get an error if they actually try to read or write. */
+  API_EVENT(conn, NETCONN_EVT_RCVPLUS, 0);
+  API_EVENT(conn, NETCONN_EVT_SENDPLUS, 0);
+
+  /* pass NULL-message to recvmbox to wake up pending recv */
+  if (sys_mbox_valid(&conn->recvmbox)) {
+    /* use trypost to prevent deadlock */
+    sys_mbox_trypost(&conn->recvmbox, NULL);
+  }
+  /* pass NULL-message to acceptmbox to wake up pending accept */
+  if (sys_mbox_valid(&conn->acceptmbox)) {
+    /* use trypost to preven deadlock */
+    sys_mbox_trypost(&conn->acceptmbox, NULL);
+  }
+
+  if ((old_state == NETCONN_WRITE) || (old_state == NETCONN_CLOSE) ||
+      (old_state == NETCONN_CONNECT)) {
+    /* calling do_writemore/do_close_internal is not necessary
+       since the pcb has already been deleted! */
+    int was_nonblocking_connect = IN_NONBLOCKING_CONNECT(conn);
+    SET_NONBLOCKING_CONNECT(conn, 0);
+
+    if (!was_nonblocking_connect) {
+      /* set error return code */
+      LWIP_ASSERT("conn->current_msg != NULL", conn->current_msg != NULL);
+      conn->current_msg->err = err;
+      conn->current_msg = NULL;
+      /* wake up the waiting task */
+      sys_sem_signal(&conn->op_completed);
+    }
+  } else {
+    LWIP_ASSERT("conn->current_msg == NULL", conn->current_msg == NULL);
+  }
+}
+
+/**
+ * Setup a tcp_pcb with the correct callback function pointers
+ * and their arguments.
+ *
+ * @param conn the TCP netconn to setup
+ */
+static void
+setup_tcp(struct netconn *conn)
+{
+  struct tcp_pcb *pcb;
+
+  pcb = conn->pcb.tcp;
+  tcp_arg(pcb, conn);
+  tcp_recv(pcb, recv_tcp);
+  tcp_sent(pcb, sent_tcp);
+  tcp_poll(pcb, poll_tcp, 4);
+  tcp_err(pcb, err_tcp);
+}
+
+/**
+ * Accept callback function for TCP netconns.
+ * Allocates a new netconn and posts that to conn->acceptmbox.
+ *
+ * @see tcp.h (struct tcp_pcb_listen.accept) for parameters and return value
+ */
+static err_t
+accept_function(void *arg, struct tcp_pcb *newpcb, err_t err)
+{
+  struct netconn *newconn;
+  struct netconn *conn = (struct netconn *)arg;
+
+  LWIP_DEBUGF(API_MSG_DEBUG, ("accept_function: newpcb->tate: %s\n", tcp_debug_state_str(newpcb->state)));
+
+  if (!sys_mbox_valid(&conn->acceptmbox)) {
+    LWIP_DEBUGF(API_MSG_DEBUG, ("accept_function: acceptmbox already deleted\n"));
+    return ERR_VAL;
+  }
+
+  /* We have to set the callback here even though
+   * the new socket is unknown. conn->socket is marked as -1. */
+  newconn = netconn_alloc(conn->type, conn->callback);
+  if (newconn == NULL) {
+    return ERR_MEM;
+  }
+  newconn->pcb.tcp = newpcb;
+  setup_tcp(newconn);
+  /* no protection: when creating the pcb, the netconn is not yet known
+     to the application thread */
+  newconn->last_err = err;
+
+  if (sys_mbox_trypost(&conn->acceptmbox, newconn) != ERR_OK) {
+    /* When returning != ERR_OK, the pcb is aborted in tcp_process(),
+       so do nothing here! */
+    newconn->pcb.tcp = NULL;
+    /* no need to drain since we know the recvmbox is empty. */
+    sys_mbox_free(&newconn->recvmbox);
+    sys_mbox_set_invalid(&newconn->recvmbox);
+    netconn_free(newconn);
+    return ERR_MEM;
+  } else {
+    /* Register event with callback */
+    API_EVENT(conn, NETCONN_EVT_RCVPLUS, 0);
+  }
+
+  return ERR_OK;
+}
+#endif /* LWIP_TCP */
+
+/**
+ * Create a new pcb of a specific type.
+ * Called from do_newconn().
+ *
+ * @param msg the api_msg_msg describing the connection type
+ * @return msg->conn->err, but the return value is currently ignored
+ */
+static void
+pcb_new(struct api_msg_msg *msg)
+{
+  LWIP_ASSERT("pcb_new: pcb already allocated", msg->conn->pcb.tcp == NULL);
+
+  /* Allocate a PCB for this connection */
+  switch(NETCONNTYPE_GROUP(msg->conn->type)) {
+#if LWIP_RAW
+  case NETCONN_RAW:
+    msg->conn->pcb.raw = raw_new(msg->msg.n.proto);
+    if(msg->conn->pcb.raw == NULL) {
+      msg->err = ERR_MEM;
+      break;
+    }
+    raw_recv(msg->conn->pcb.raw, recv_raw, msg->conn);
+    break;
+#endif /* LWIP_RAW */
+#if LWIP_UDP
+  case NETCONN_UDP:
+    msg->conn->pcb.udp = udp_new();
+    if(msg->conn->pcb.udp == NULL) {
+      msg->err = ERR_MEM;
+      break;
+    }
+#if LWIP_UDPLITE
+    if (msg->conn->type==NETCONN_UDPLITE) {
+      udp_setflags(msg->conn->pcb.udp, UDP_FLAGS_UDPLITE);
+    }
+#endif /* LWIP_UDPLITE */
+    if (msg->conn->type==NETCONN_UDPNOCHKSUM) {
+      udp_setflags(msg->conn->pcb.udp, UDP_FLAGS_NOCHKSUM);
+    }
+    udp_recv(msg->conn->pcb.udp, recv_udp, msg->conn);
+    break;
+#endif /* LWIP_UDP */
+#if LWIP_TCP
+  case NETCONN_TCP:
+    msg->conn->pcb.tcp = tcp_new();
+    if(msg->conn->pcb.tcp == NULL) {
+      msg->err = ERR_MEM;
+      break;
+    }
+    setup_tcp(msg->conn);
+    break;
+#endif /* LWIP_TCP */
+  default:
+    /* Unsupported netconn type, e.g. protocol disabled */
+    msg->err = ERR_VAL;
+    break;
+  }
+}
+
+/**
+ * Create a new pcb of a specific type inside a netconn.
+ * Called from netconn_new_with_proto_and_callback.
+ *
+ * @param msg the api_msg_msg describing the connection type
+ */
+void
+do_newconn(struct api_msg_msg *msg)
+{
+  msg->err = ERR_OK;
+  if(msg->conn->pcb.tcp == NULL) {
+    pcb_new(msg);
+  }
+  /* Else? This "new" connection already has a PCB allocated. */
+  /* Is this an error condition? Should it be deleted? */
+  /* We currently just are happy and return. */
+
+  TCPIP_APIMSG_ACK(msg);
+}
+
+/**
+ * Create a new netconn (of a specific type) that has a callback function.
+ * The corresponding pcb is NOT created!
+ *
+ * @param t the type of 'connection' to create (@see enum netconn_type)
+ * @param proto the IP protocol for RAW IP pcbs
+ * @param callback a function to call on status changes (RX available, TX'ed)
+ * @return a newly allocated struct netconn or
+ *         NULL on memory error
+ */
+struct netconn*
+netconn_alloc(enum netconn_type t, netconn_callback callback)
+{
+  struct netconn *conn;
+  int size;
+
+  conn = (struct netconn *)memp_malloc(MEMP_NETCONN);
+  if (conn == NULL) {
+    return NULL;
+  }
+
+  conn->last_err = ERR_OK;
+  conn->type = t;
+  conn->pcb.tcp = NULL;
+
+#if (DEFAULT_RAW_RECVMBOX_SIZE == DEFAULT_UDP_RECVMBOX_SIZE) && \
+    (DEFAULT_RAW_RECVMBOX_SIZE == DEFAULT_TCP_RECVMBOX_SIZE)
+  size = DEFAULT_RAW_RECVMBOX_SIZE;
+#else
+  switch(NETCONNTYPE_GROUP(t)) {
+#if LWIP_RAW
+  case NETCONN_RAW:
+    size = DEFAULT_RAW_RECVMBOX_SIZE;
+    break;
+#endif /* LWIP_RAW */
+#if LWIP_UDP
+  case NETCONN_UDP:
+    size = DEFAULT_UDP_RECVMBOX_SIZE;
+    break;
+#endif /* LWIP_UDP */
+#if LWIP_TCP
+  case NETCONN_TCP:
+    size = DEFAULT_TCP_RECVMBOX_SIZE;
+    break;
+#endif /* LWIP_TCP */
+  default:
+    LWIP_ASSERT("netconn_alloc: undefined netconn_type", 0);
+    break;
+  }
+#endif
+
+  if (sys_sem_new(&conn->op_completed, 0) != ERR_OK) {
+    memp_free(MEMP_NETCONN, conn);
+    return NULL;
+  }
+  if (sys_mbox_new(&conn->recvmbox, size) != ERR_OK) {
+    sys_sem_free(&conn->op_completed);
+    memp_free(MEMP_NETCONN, conn);
+    return NULL;
+  }
+
+#if LWIP_TCP
+  sys_mbox_set_invalid(&conn->acceptmbox);
+#endif
+  conn->state        = NETCONN_NONE;
+#if LWIP_SOCKET
+  /* initialize socket to -1 since 0 is a valid socket */
+  conn->socket       = -1;
+#endif /* LWIP_SOCKET */
+  conn->callback     = callback;
+#if LWIP_TCP
+  conn->current_msg  = NULL;
+  conn->write_offset = 0;
+#endif /* LWIP_TCP */
+#if LWIP_SO_RCVTIMEO
+  conn->recv_timeout = 0;
+#endif /* LWIP_SO_RCVTIMEO */
+#if LWIP_SO_RCVBUF
+  conn->recv_bufsize = RECV_BUFSIZE_DEFAULT;
+  conn->recv_avail   = 0;
+#endif /* LWIP_SO_RCVBUF */
+  conn->flags = 0;
+  return conn;
+}
+
+/**
+ * Delete a netconn and all its resources.
+ * The pcb is NOT freed (since we might not be in the right thread context do this).
+ *
+ * @param conn the netconn to free
+ */
+void
+netconn_free(struct netconn *conn)
+{
+  LWIP_ASSERT("PCB must be deallocated outside this function", conn->pcb.tcp == NULL);
+  LWIP_ASSERT("recvmbox must be deallocated before calling this function",
+    !sys_mbox_valid(&conn->recvmbox));
+#if LWIP_TCP
+  LWIP_ASSERT("acceptmbox must be deallocated before calling this function",
+    !sys_mbox_valid(&conn->acceptmbox));
+#endif /* LWIP_TCP */
+
+  sys_sem_free(&conn->op_completed);
+  sys_sem_set_invalid(&conn->op_completed);
+
+  memp_free(MEMP_NETCONN, conn);
+}
+
+/**
+ * Delete rcvmbox and acceptmbox of a netconn and free the left-over data in
+ * these mboxes
+ *
+ * @param conn the netconn to free
+ * @bytes_drained bytes drained from recvmbox
+ * @accepts_drained pending connections drained from acceptmbox
+ */
+static void
+netconn_drain(struct netconn *conn)
+{
+  void *mem;
+#if LWIP_TCP
+  struct pbuf *p;
+#endif /* LWIP_TCP */
+
+  /* This runs in tcpip_thread, so we don't need to lock against rx packets */
+
+  /* Delete and drain the recvmbox. */
+  if (sys_mbox_valid(&conn->recvmbox)) {
+    while (sys_mbox_tryfetch(&conn->recvmbox, &mem) != SYS_MBOX_EMPTY) {
+#if LWIP_TCP
+      if (conn->type == NETCONN_TCP) {
+        if(mem != NULL) {
+          p = (struct pbuf*)mem;
+          /* pcb might be set to NULL already by err_tcp() */
+          if (conn->pcb.tcp != NULL) {
+            tcp_recved(conn->pcb.tcp, p->tot_len);
+          }
+          pbuf_free(p);
+        }
+      } else
+#endif /* LWIP_TCP */
+      {
+        netbuf_delete((struct netbuf *)mem);
+      }
+    }
+    sys_mbox_free(&conn->recvmbox);
+    sys_mbox_set_invalid(&conn->recvmbox);
+  }
+
+  /* Delete and drain the acceptmbox. */
+#if LWIP_TCP
+  if (sys_mbox_valid(&conn->acceptmbox)) {
+    while (sys_mbox_tryfetch(&conn->acceptmbox, &mem) != SYS_MBOX_EMPTY) {
+      struct netconn *newconn = (struct netconn *)mem;
+      /* Only tcp pcbs have an acceptmbox, so no need to check conn->type */
+      /* pcb might be set to NULL already by err_tcp() */
+      if (conn->pcb.tcp != NULL) {
+        tcp_accepted(conn->pcb.tcp);
+      }
+      /* drain recvmbox */
+      netconn_drain(newconn);
+      if (newconn->pcb.tcp != NULL) {
+        tcp_abort(newconn->pcb.tcp);
+        newconn->pcb.tcp = NULL;
+      }
+      netconn_free(newconn);
+    }
+    sys_mbox_free(&conn->acceptmbox);
+    sys_mbox_set_invalid(&conn->acceptmbox);
+  }
+#endif /* LWIP_TCP */
+}
+
+#if LWIP_TCP
+/**
+ * Internal helper function to close a TCP netconn: since this sometimes
+ * doesn't work at the first attempt, this function is called from multiple
+ * places.
+ *
+ * @param conn the TCP netconn to close
+ */
+static void
+do_close_internal(struct netconn *conn)
+{
+  err_t err;
+  u8_t shut, shut_rx, shut_tx, close;
+
+  LWIP_ASSERT("invalid conn", (conn != NULL));
+  LWIP_ASSERT("this is for tcp netconns only", (conn->type == NETCONN_TCP));
+  LWIP_ASSERT("conn must be in state NETCONN_CLOSE", (conn->state == NETCONN_CLOSE));
+  LWIP_ASSERT("pcb already closed", (conn->pcb.tcp != NULL));
+  LWIP_ASSERT("conn->current_msg != NULL", conn->current_msg != NULL);
+
+  shut = conn->current_msg->msg.sd.shut;
+  shut_rx = shut & NETCONN_SHUT_RD;
+  shut_tx = shut & NETCONN_SHUT_WR;
+  /* shutting down both ends is the same as closing */
+  close = shut == NETCONN_SHUT_RDWR;
+
+  /* Set back some callback pointers */
+  if (close) {
+    tcp_arg(conn->pcb.tcp, NULL);
+  }
+  if (conn->pcb.tcp->state == LISTEN) {
+    tcp_accept(conn->pcb.tcp, NULL);
+  } else {
+    /* some callbacks have to be reset if tcp_close is not successful */
+    if (shut_rx) {
+      tcp_recv(conn->pcb.tcp, NULL);
+      tcp_accept(conn->pcb.tcp, NULL);
+    }
+    if (shut_tx) {
+      tcp_sent(conn->pcb.tcp, NULL);
+    }
+    if (close) {
+      tcp_poll(conn->pcb.tcp, NULL, 4);
+      tcp_err(conn->pcb.tcp, NULL);
+    }
+  }
+  /* Try to close the connection */
+  if (shut == NETCONN_SHUT_RDWR) {
+    err = tcp_close(conn->pcb.tcp);
+  } else {
+    err = tcp_shutdown(conn->pcb.tcp, shut & NETCONN_SHUT_RD, shut & NETCONN_SHUT_WR);
+  }
+  if (err == ERR_OK) {
+    /* Closing succeeded */
+    conn->current_msg->err = ERR_OK;
+    conn->current_msg = NULL;
+    conn->state = NETCONN_NONE;
+    /* Set back some callback pointers as conn is going away */
+    conn->pcb.tcp = NULL;
+    /* Trigger select() in socket layer. Make sure everybody notices activity
+       on the connection, error first! */
+    if (close) {
+      API_EVENT(conn, NETCONN_EVT_ERROR, 0);
+    }
+    if (shut_rx) {
+      API_EVENT(conn, NETCONN_EVT_RCVPLUS, 0);
+    }
+    if (shut_tx) {
+      API_EVENT(conn, NETCONN_EVT_SENDPLUS, 0);
+    }
+    /* wake up the application task */
+    sys_sem_signal(&conn->op_completed);
+  } else {
+    /* Closing failed, restore some of the callbacks */
+    /* Closing of listen pcb will never fail! */
+    LWIP_ASSERT("Closing a listen pcb may not fail!", (conn->pcb.tcp->state != LISTEN));
+    tcp_sent(conn->pcb.tcp, sent_tcp);
+    tcp_poll(conn->pcb.tcp, poll_tcp, 4);
+    tcp_err(conn->pcb.tcp, err_tcp);
+    tcp_arg(conn->pcb.tcp, conn);
+    /* don't restore recv callback: we don't want to receive any more data */
+  }
+  /* If closing didn't succeed, we get called again either
+     from poll_tcp or from sent_tcp */
+}
+#endif /* LWIP_TCP */
+
+/**
+ * Delete the pcb inside a netconn.
+ * Called from netconn_delete.
+ *
+ * @param msg the api_msg_msg pointing to the connection
+ */
+void
+do_delconn(struct api_msg_msg *msg)
+{
+  /* @todo TCP: abort running write/connect? */
+ if ((msg->conn->state != NETCONN_NONE) &&
+     (msg->conn->state != NETCONN_LISTEN) &&
+     (msg->conn->state != NETCONN_CONNECT)) {
+    /* this only happens for TCP netconns */
+    LWIP_ASSERT("msg->conn->type == NETCONN_TCP", msg->conn->type == NETCONN_TCP);
+    msg->err = ERR_INPROGRESS;
+  } else {
+    LWIP_ASSERT("blocking connect in progress",
+      (msg->conn->state != NETCONN_CONNECT) || IN_NONBLOCKING_CONNECT(msg->conn));
+    /* Drain and delete mboxes */
+    netconn_drain(msg->conn);
+
+    if (msg->conn->pcb.tcp != NULL) {
+
+      switch (NETCONNTYPE_GROUP(msg->conn->type)) {
+#if LWIP_RAW
+      case NETCONN_RAW:
+        raw_remove(msg->conn->pcb.raw);
+        break;
+#endif /* LWIP_RAW */
+#if LWIP_UDP
+      case NETCONN_UDP:
+        msg->conn->pcb.udp->recv_arg = NULL;
+        udp_remove(msg->conn->pcb.udp);
+        break;
+#endif /* LWIP_UDP */
+#if LWIP_TCP
+      case NETCONN_TCP:
+        LWIP_ASSERT("already writing or closing", msg->conn->current_msg == NULL &&
+          msg->conn->write_offset == 0);
+        msg->conn->state = NETCONN_CLOSE;
+        msg->msg.sd.shut = NETCONN_SHUT_RDWR;
+        msg->conn->current_msg = msg;
+        do_close_internal(msg->conn);
+        /* API_EVENT is called inside do_close_internal, before releasing
+           the application thread, so we can return at this point! */
+        return;
+#endif /* LWIP_TCP */
+      default:
+        break;
+      }
+      msg->conn->pcb.tcp = NULL;
+    }
+    /* tcp netconns don't come here! */
+
+    /* @todo: this lets select make the socket readable and writable,
+       which is wrong! errfd instead? */
+    API_EVENT(msg->conn, NETCONN_EVT_RCVPLUS, 0);
+    API_EVENT(msg->conn, NETCONN_EVT_SENDPLUS, 0);
+  }
+  if (sys_sem_valid(&msg->conn->op_completed)) {
+    sys_sem_signal(&msg->conn->op_completed);
+  }
+}
+
+/**
+ * Bind a pcb contained in a netconn
+ * Called from netconn_bind.
+ *
+ * @param msg the api_msg_msg pointing to the connection and containing
+ *            the IP address and port to bind to
+ */
+void
+do_bind(struct api_msg_msg *msg)
+{
+  if (ERR_IS_FATAL(msg->conn->last_err)) {
+    msg->err = msg->conn->last_err;
+  } else {
+    msg->err = ERR_VAL;
+    if (msg->conn->pcb.tcp != NULL) {
+      switch (NETCONNTYPE_GROUP(msg->conn->type)) {
+#if LWIP_RAW
+      case NETCONN_RAW:
+        msg->err = raw_bind(msg->conn->pcb.raw, msg->msg.bc.ipaddr);
+        break;
+#endif /* LWIP_RAW */
+#if LWIP_UDP
+      case NETCONN_UDP:
+        msg->err = udp_bind(msg->conn->pcb.udp, msg->msg.bc.ipaddr, msg->msg.bc.port);
+        break;
+#endif /* LWIP_UDP */
+#if LWIP_TCP
+      case NETCONN_TCP:
+        msg->err = tcp_bind(msg->conn->pcb.tcp, msg->msg.bc.ipaddr, msg->msg.bc.port);
+        break;
+#endif /* LWIP_TCP */
+      default:
+        break;
+      }
+    }
+  }
+  TCPIP_APIMSG_ACK(msg);
+}
+
+#if LWIP_TCP
+/**
+ * TCP callback function if a connection (opened by tcp_connect/do_connect) has
+ * been established (or reset by the remote host).
+ *
+ * @see tcp.h (struct tcp_pcb.connected) for parameters and return values
+ */
+static err_t
+do_connected(void *arg, struct tcp_pcb *pcb, err_t err)
+{
+  struct netconn *conn;
+  int was_blocking;
+
+  LWIP_UNUSED_ARG(pcb);
+
+  conn = (struct netconn *)arg;
+
+  if (conn == NULL) {
+    return ERR_VAL;
+  }
+
+  LWIP_ASSERT("conn->state == NETCONN_CONNECT", conn->state == NETCONN_CONNECT);
+  LWIP_ASSERT("(conn->current_msg != NULL) || conn->in_non_blocking_connect",
+    (conn->current_msg != NULL) || IN_NONBLOCKING_CONNECT(conn));
+
+  if (conn->current_msg != NULL) {
+    conn->current_msg->err = err;
+  }
+  if ((conn->type == NETCONN_TCP) && (err == ERR_OK)) {
+    setup_tcp(conn);
+  }
+  was_blocking = !IN_NONBLOCKING_CONNECT(conn);
+  SET_NONBLOCKING_CONNECT(conn, 0);
+  conn->current_msg = NULL;
+  conn->state = NETCONN_NONE;
+  if (!was_blocking) {
+    NETCONN_SET_SAFE_ERR(conn, ERR_OK);
+  }
+  API_EVENT(conn, NETCONN_EVT_SENDPLUS, 0);
+
+  if (was_blocking) {
+    sys_sem_signal(&conn->op_completed);
+  }
+  return ERR_OK;
+}
+#endif /* LWIP_TCP */
+
+/**
+ * Connect a pcb contained inside a netconn
+ * Called from netconn_connect.
+ *
+ * @param msg the api_msg_msg pointing to the connection and containing
+ *            the IP address and port to connect to
+ */
+void
+do_connect(struct api_msg_msg *msg)
+{
+  if (msg->conn->pcb.tcp == NULL) {
+    /* This may happen when calling netconn_connect() a second time */
+    msg->err = ERR_CLSD;
+  } else {
+    switch (NETCONNTYPE_GROUP(msg->conn->type)) {
+#if LWIP_RAW
+  case NETCONN_RAW:
+    msg->err = raw_connect(msg->conn->pcb.raw, msg->msg.bc.ipaddr);
+    break;
+#endif /* LWIP_RAW */
+#if LWIP_UDP
+  case NETCONN_UDP:
+    msg->err = udp_connect(msg->conn->pcb.udp, msg->msg.bc.ipaddr, msg->msg.bc.port);
+    break;
+#endif /* LWIP_UDP */
+#if LWIP_TCP
+  case NETCONN_TCP:
+    /* Prevent connect while doing any other action. */
+    if (msg->conn->state != NETCONN_NONE) {
+      msg->err = ERR_ISCONN;
+    } else {
+      setup_tcp(msg->conn);
+      msg->err = tcp_connect(msg->conn->pcb.tcp, msg->msg.bc.ipaddr,
+        msg->msg.bc.port, do_connected);
+      if (msg->err == ERR_OK) {
+        u8_t non_blocking = netconn_is_nonblocking(msg->conn);
+        msg->conn->state = NETCONN_CONNECT;
+        SET_NONBLOCKING_CONNECT(msg->conn, non_blocking);
+        if (non_blocking) {
+          msg->err = ERR_INPROGRESS;
+        } else {
+          msg->conn->current_msg = msg;
+          /* sys_sem_signal() is called from do_connected (or err_tcp()),
+          * when the connection is established! */
+          return;
+        }
+      }
+    }
+    break;
+#endif /* LWIP_TCP */
+  default:
+    LWIP_ERROR("Invalid netconn type", 0, do{ msg->err = ERR_VAL; }while(0));
+    break;
+    }
+  }
+  sys_sem_signal(&msg->conn->op_completed);
+}
+
+/**
+ * Connect a pcb contained inside a netconn
+ * Only used for UDP netconns.
+ * Called from netconn_disconnect.
+ *
+ * @param msg the api_msg_msg pointing to the connection to disconnect
+ */
+void
+do_disconnect(struct api_msg_msg *msg)
+{
+#if LWIP_UDP
+  if (NETCONNTYPE_GROUP(msg->conn->type) == NETCONN_UDP) {
+    udp_disconnect(msg->conn->pcb.udp);
+    msg->err = ERR_OK;
+  } else
+#endif /* LWIP_UDP */
+  {
+    msg->err = ERR_VAL;
+  }
+  TCPIP_APIMSG_ACK(msg);
+}
+
+#if LWIP_TCP
+/**
+ * Set a TCP pcb contained in a netconn into listen mode
+ * Called from netconn_listen.
+ *
+ * @param msg the api_msg_msg pointing to the connection
+ */
+void
+do_listen(struct api_msg_msg *msg)
+{
+  if (ERR_IS_FATAL(msg->conn->last_err)) {
+    msg->err = msg->conn->last_err;
+  } else {
+    msg->err = ERR_CONN;
+    if (msg->conn->pcb.tcp != NULL) {
+      if (msg->conn->type == NETCONN_TCP) {
+        if (msg->conn->state == NETCONN_NONE) {
+#if TCP_LISTEN_BACKLOG
+          struct tcp_pcb* lpcb = tcp_listen_with_backlog(msg->conn->pcb.tcp, msg->msg.lb.backlog);
+#else  /* TCP_LISTEN_BACKLOG */
+          struct tcp_pcb* lpcb = tcp_listen(msg->conn->pcb.tcp);
+#endif /* TCP_LISTEN_BACKLOG */
+          if (lpcb == NULL) {
+            /* in this case, the old pcb is still allocated */
+            msg->err = ERR_MEM;
+          } else {
+            /* delete the recvmbox and allocate the acceptmbox */
+            if (sys_mbox_valid(&msg->conn->recvmbox)) {
+              /** @todo: should we drain the recvmbox here? */
+              sys_mbox_free(&msg->conn->recvmbox);
+              sys_mbox_set_invalid(&msg->conn->recvmbox);
+            }
+            msg->err = ERR_OK;
+            if (!sys_mbox_valid(&msg->conn->acceptmbox)) {
+              msg->err = sys_mbox_new(&msg->conn->acceptmbox, DEFAULT_ACCEPTMBOX_SIZE);
+            }
+            if (msg->err == ERR_OK) {
+              msg->conn->state = NETCONN_LISTEN;
+              msg->conn->pcb.tcp = lpcb;
+              tcp_arg(msg->conn->pcb.tcp, msg->conn);
+              tcp_accept(msg->conn->pcb.tcp, accept_function);
+            } else {
+              /* since the old pcb is already deallocated, free lpcb now */
+              tcp_close(lpcb);
+              msg->conn->pcb.tcp = NULL;
+            }
+          }
+        }
+      }
+    }
+  }
+  TCPIP_APIMSG_ACK(msg);
+}
+#endif /* LWIP_TCP */
+
+/**
+ * Send some data on a RAW or UDP pcb contained in a netconn
+ * Called from netconn_send
+ *
+ * @param msg the api_msg_msg pointing to the connection
+ */
+void
+do_send(struct api_msg_msg *msg)
+{
+  if (ERR_IS_FATAL(msg->conn->last_err)) {
+    msg->err = msg->conn->last_err;
+  } else {
+    msg->err = ERR_CONN;
+    if (msg->conn->pcb.tcp != NULL) {
+      switch (NETCONNTYPE_GROUP(msg->conn->type)) {
+#if LWIP_RAW
+      case NETCONN_RAW:
+        if (ip_addr_isany(&msg->msg.b->addr)) {
+          msg->err = raw_send(msg->conn->pcb.raw, msg->msg.b->p);
+        } else {
+          msg->err = raw_sendto(msg->conn->pcb.raw, msg->msg.b->p, &msg->msg.b->addr);
+        }
+        break;
+#endif
+#if LWIP_UDP
+      case NETCONN_UDP:
+#if LWIP_CHECKSUM_ON_COPY
+        if (ip_addr_isany(&msg->msg.b->addr)) {
+          msg->err = udp_send_chksum(msg->conn->pcb.udp, msg->msg.b->p,
+            msg->msg.b->flags & NETBUF_FLAG_CHKSUM, msg->msg.b->toport_chksum);
+        } else {
+          msg->err = udp_sendto_chksum(msg->conn->pcb.udp, msg->msg.b->p,
+            &msg->msg.b->addr, msg->msg.b->port,
+            msg->msg.b->flags & NETBUF_FLAG_CHKSUM, msg->msg.b->toport_chksum);
+        }
+#else /* LWIP_CHECKSUM_ON_COPY */
+        if (ip_addr_isany(&msg->msg.b->addr)) {
+          msg->err = udp_send(msg->conn->pcb.udp, msg->msg.b->p);
+        } else {
+          msg->err = udp_sendto(msg->conn->pcb.udp, msg->msg.b->p, &msg->msg.b->addr, msg->msg.b->port);
+        }
+#endif /* LWIP_CHECKSUM_ON_COPY */
+        break;
+#endif /* LWIP_UDP */
+      default:
+        break;
+      }
+    }
+  }
+  TCPIP_APIMSG_ACK(msg);
+}
+
+#if LWIP_TCP
+/**
+ * Indicate data has been received from a TCP pcb contained in a netconn
+ * Called from netconn_recv
+ *
+ * @param msg the api_msg_msg pointing to the connection
+ */
+void
+do_recv(struct api_msg_msg *msg)
+{
+  msg->err = ERR_OK;
+  if (msg->conn->pcb.tcp != NULL) {
+    if (msg->conn->type == NETCONN_TCP) {
+#if TCP_LISTEN_BACKLOG
+      if (msg->conn->pcb.tcp->state == LISTEN) {
+        tcp_accepted(msg->conn->pcb.tcp);
+      } else
+#endif /* TCP_LISTEN_BACKLOG */
+      {
+        u32_t remaining = msg->msg.r.len;
+        do {
+          u16_t recved = (remaining > 0xffff) ? 0xffff : (u16_t)remaining;
+          tcp_recved(msg->conn->pcb.tcp, recved);
+          remaining -= recved;
+        }while(remaining != 0);
+      }
+    }
+  }
+  TCPIP_APIMSG_ACK(msg);
+}
+
+/**
+ * See if more data needs to be written from a previous call to netconn_write.
+ * Called initially from do_write. If the first call can't send all data
+ * (because of low memory or empty send-buffer), this function is called again
+ * from sent_tcp() or poll_tcp() to send more data. If all data is sent, the
+ * blocking application thread (waiting in netconn_write) is released.
+ *
+ * @param conn netconn (that is currently in state NETCONN_WRITE) to process
+ * @return ERR_OK
+ *         ERR_MEM if LWIP_TCPIP_CORE_LOCKING=1 and sending hasn't yet finished
+ */
+static err_t
+do_writemore(struct netconn *conn)
+{
+  err_t err = ERR_OK;
+  void *dataptr;
+  u16_t len, available;
+  u8_t write_finished = 0;
+  size_t diff;
+  u8_t dontblock = netconn_is_nonblocking(conn) ||
+       (conn->current_msg->msg.w.apiflags & NETCONN_DONTBLOCK);
+  u8_t apiflags = conn->current_msg->msg.w.apiflags;
+
+  LWIP_ASSERT("conn != NULL", conn != NULL);
+  LWIP_ASSERT("conn->state == NETCONN_WRITE", (conn->state == NETCONN_WRITE));
+  LWIP_ASSERT("conn->current_msg != NULL", conn->current_msg != NULL);
+  LWIP_ASSERT("conn->pcb.tcp != NULL", conn->pcb.tcp != NULL);
+  LWIP_ASSERT("conn->write_offset < conn->current_msg->msg.w.len",
+    conn->write_offset < conn->current_msg->msg.w.len);
+
+  dataptr = (u8_t*)conn->current_msg->msg.w.dataptr + conn->write_offset;
+  diff = conn->current_msg->msg.w.len - conn->write_offset;
+  if (diff > 0xffffUL) { /* max_u16_t */
+    len = 0xffff;
+#if LWIP_TCPIP_CORE_LOCKING
+    conn->flags |= NETCONN_FLAG_WRITE_DELAYED;
+#endif
+    apiflags |= TCP_WRITE_FLAG_MORE;
+  } else {
+    len = (u16_t)diff;
+  }
+  available = tcp_sndbuf(conn->pcb.tcp);
+  if (available < len) {
+    /* don't try to write more than sendbuf */
+    len = available;
+#if LWIP_TCPIP_CORE_LOCKING
+    conn->flags |= NETCONN_FLAG_WRITE_DELAYED;
+#endif
+    apiflags |= TCP_WRITE_FLAG_MORE;
+  }
+  if (dontblock && (len < conn->current_msg->msg.w.len)) {
+    /* failed to send all data at once -> nonblocking write not possible */
+    err = ERR_MEM;
+  }
+  if (err == ERR_OK) {
+    LWIP_ASSERT("do_writemore: invalid length!", ((conn->write_offset + len) <= conn->current_msg->msg.w.len));
+    err = tcp_write(conn->pcb.tcp, dataptr, len, apiflags);
+  }
+  if (dontblock && (err == ERR_MEM)) {
+    /* nonblocking write failed */
+    write_finished = 1;
+    err = ERR_WOULDBLOCK;
+    /* let poll_tcp check writable space to mark the pcb
+       writable again */
+    conn->flags |= NETCONN_FLAG_CHECK_WRITESPACE;
+    /* let select mark this pcb as non-writable. */
+    API_EVENT(conn, NETCONN_EVT_SENDMINUS, len);
+  } else {
+    /* if OK or memory error, check available space */
+    if (((err == ERR_OK) || (err == ERR_MEM)) &&
+        ((tcp_sndbuf(conn->pcb.tcp) <= TCP_SNDLOWAT) ||
+         (tcp_sndqueuelen(conn->pcb.tcp) >= TCP_SNDQUEUELOWAT))) {
+      /* The queued byte- or pbuf-count exceeds the configured low-water limit,
+         let select mark this pcb as non-writable. */
+      API_EVENT(conn, NETCONN_EVT_SENDMINUS, len);
+    }
+
+    if (err == ERR_OK) {
+      conn->write_offset += len;
+      if (conn->write_offset == conn->current_msg->msg.w.len) {
+        /* everything was written */
+        write_finished = 1;
+        conn->write_offset = 0;
+      }
+      tcp_output(conn->pcb.tcp);
+    } else if (err == ERR_MEM) {
+      /* If ERR_MEM, we wait for sent_tcp or poll_tcp to be called
+         we do NOT return to the application thread, since ERR_MEM is
+         only a temporary error! */
+
+      /* tcp_write returned ERR_MEM, try tcp_output anyway */
+      tcp_output(conn->pcb.tcp);
+
+  #if LWIP_TCPIP_CORE_LOCKING
+      conn->flags |= NETCONN_FLAG_WRITE_DELAYED;
+  #endif
+    } else {
+      /* On errors != ERR_MEM, we don't try writing any more but return
+         the error to the application thread. */
+      write_finished = 1;
+    }
+  }
+
+  if (write_finished) {
+    /* everything was written: set back connection state
+       and back to application task */
+    conn->current_msg->err = err;
+    conn->current_msg = NULL;
+    conn->state = NETCONN_NONE;
+#if LWIP_TCPIP_CORE_LOCKING
+    if ((conn->flags & NETCONN_FLAG_WRITE_DELAYED) != 0)
+#endif
+    {
+      sys_sem_signal(&conn->op_completed);
+    }
+  }
+#if LWIP_TCPIP_CORE_LOCKING
+  else
+    return ERR_MEM;
+#endif
+  return ERR_OK;
+}
+#endif /* LWIP_TCP */
+
+/**
+ * Send some data on a TCP pcb contained in a netconn
+ * Called from netconn_write
+ *
+ * @param msg the api_msg_msg pointing to the connection
+ */
+void
+do_write(struct api_msg_msg *msg)
+{
+  if (ERR_IS_FATAL(msg->conn->last_err)) {
+    msg->err = msg->conn->last_err;
+  } else {
+    if (msg->conn->type == NETCONN_TCP) {
+#if LWIP_TCP
+      if (msg->conn->state != NETCONN_NONE) {
+        /* netconn is connecting, closing or in blocking write */
+        msg->err = ERR_INPROGRESS;
+      } else if (msg->conn->pcb.tcp != NULL) {
+        msg->conn->state = NETCONN_WRITE;
+        /* set all the variables used by do_writemore */
+        LWIP_ASSERT("already writing or closing", msg->conn->current_msg == NULL &&
+          msg->conn->write_offset == 0);
+        LWIP_ASSERT("msg->msg.w.len != 0", msg->msg.w.len != 0);
+        msg->conn->current_msg = msg;
+        msg->conn->write_offset = 0;
+#if LWIP_TCPIP_CORE_LOCKING
+        msg->conn->flags &= ~NETCONN_FLAG_WRITE_DELAYED;
+        if (do_writemore(msg->conn) != ERR_OK) {
+          LWIP_ASSERT("state!", msg->conn->state == NETCONN_WRITE);
+          UNLOCK_TCPIP_CORE();
+          sys_arch_sem_wait(&msg->conn->op_completed, 0);
+          LOCK_TCPIP_CORE();
+          LWIP_ASSERT("state!", msg->conn->state == NETCONN_NONE);
+        }
+#else /* LWIP_TCPIP_CORE_LOCKING */
+        do_writemore(msg->conn);
+#endif /* LWIP_TCPIP_CORE_LOCKING */
+        /* for both cases: if do_writemore was called, don't ACK the APIMSG
+           since do_writemore ACKs it! */
+        return;
+      } else {
+        msg->err = ERR_CONN;
+      }
+#else /* LWIP_TCP */
+      msg->err = ERR_VAL;
+#endif /* LWIP_TCP */
+#if (LWIP_UDP || LWIP_RAW)
+    } else {
+      msg->err = ERR_VAL;
+#endif /* (LWIP_UDP || LWIP_RAW) */
+    }
+  }
+  TCPIP_APIMSG_ACK(msg);
+}
+
+/**
+ * Return a connection's local or remote address
+ * Called from netconn_getaddr
+ *
+ * @param msg the api_msg_msg pointing to the connection
+ */
+void
+do_getaddr(struct api_msg_msg *msg)
+{
+  if (msg->conn->pcb.ip != NULL) {
+    *(msg->msg.ad.ipaddr) = (msg->msg.ad.local ? msg->conn->pcb.ip->local_ip :
+                             msg->conn->pcb.ip->remote_ip);
+
+    msg->err = ERR_OK;
+    switch (NETCONNTYPE_GROUP(msg->conn->type)) {
+#if LWIP_RAW
+    case NETCONN_RAW:
+      if (msg->msg.ad.local) {
+        *(msg->msg.ad.port) = msg->conn->pcb.raw->protocol;
+      } else {
+        /* return an error as connecting is only a helper for upper layers */
+        msg->err = ERR_CONN;
+      }
+      break;
+#endif /* LWIP_RAW */
+#if LWIP_UDP
+    case NETCONN_UDP:
+      if (msg->msg.ad.local) {
+        *(msg->msg.ad.port) = msg->conn->pcb.udp->local_port;
+      } else {
+        if ((msg->conn->pcb.udp->flags & UDP_FLAGS_CONNECTED) == 0) {
+          msg->err = ERR_CONN;
+        } else {
+          *(msg->msg.ad.port) = msg->conn->pcb.udp->remote_port;
+        }
+      }
+      break;
+#endif /* LWIP_UDP */
+#if LWIP_TCP
+    case NETCONN_TCP:
+      *(msg->msg.ad.port) = (msg->msg.ad.local?msg->conn->pcb.tcp->local_port:msg->conn->pcb.tcp->remote_port);
+      break;
+#endif /* LWIP_TCP */
+    default:
+      LWIP_ASSERT("invalid netconn_type", 0);
+      break;
+    }
+  } else {
+    msg->err = ERR_CONN;
+  }
+  TCPIP_APIMSG_ACK(msg);
+}
+
+/**
+ * Close a TCP pcb contained in a netconn
+ * Called from netconn_close
+ *
+ * @param msg the api_msg_msg pointing to the connection
+ */
+void
+do_close(struct api_msg_msg *msg)
+{
+#if LWIP_TCP
+  /* @todo: abort running write/connect? */
+  if ((msg->conn->state != NETCONN_NONE) && (msg->conn->state != NETCONN_LISTEN)) {
+    /* this only happens for TCP netconns */
+    LWIP_ASSERT("msg->conn->type == NETCONN_TCP", msg->conn->type == NETCONN_TCP);
+    msg->err = ERR_INPROGRESS;
+  } else if ((msg->conn->pcb.tcp != NULL) && (msg->conn->type == NETCONN_TCP)) {
+    if ((msg->msg.sd.shut != NETCONN_SHUT_RDWR) && (msg->conn->state == NETCONN_LISTEN)) {
+      /* LISTEN doesn't support half shutdown */
+      msg->err = ERR_CONN;
+    } else {
+      if (msg->msg.sd.shut & NETCONN_SHUT_RD) {
+        /* Drain and delete mboxes */
+        netconn_drain(msg->conn);
+      }
+      LWIP_ASSERT("already writing or closing", msg->conn->current_msg == NULL &&
+        msg->conn->write_offset == 0);
+      msg->conn->state = NETCONN_CLOSE;
+      msg->conn->current_msg = msg;
+      do_close_internal(msg->conn);
+      /* for tcp netconns, do_close_internal ACKs the message */
+      return;
+    }
+  } else
+#endif /* LWIP_TCP */
+  {
+    msg->err = ERR_VAL;
+  }
+  sys_sem_signal(&msg->conn->op_completed);
+}
+
+#if LWIP_IGMP
+/**
+ * Join multicast groups for UDP netconns.
+ * Called from netconn_join_leave_group
+ *
+ * @param msg the api_msg_msg pointing to the connection
+ */
+void
+do_join_leave_group(struct api_msg_msg *msg)
+{ 
+  if (ERR_IS_FATAL(msg->conn->last_err)) {
+    msg->err = msg->conn->last_err;
+  } else {
+    if (msg->conn->pcb.tcp != NULL) {
+      if (NETCONNTYPE_GROUP(msg->conn->type) == NETCONN_UDP) {
+#if LWIP_UDP
+        if (msg->msg.jl.join_or_leave == NETCONN_JOIN) {
+          msg->err = igmp_joingroup(msg->msg.jl.netif_addr, msg->msg.jl.multiaddr);
+        } else {
+          msg->err = igmp_leavegroup(msg->msg.jl.netif_addr, msg->msg.jl.multiaddr);
+        }
+#endif /* LWIP_UDP */
+#if (LWIP_TCP || LWIP_RAW)
+      } else {
+        msg->err = ERR_VAL;
+#endif /* (LWIP_TCP || LWIP_RAW) */
+      }
+    } else {
+      msg->err = ERR_CONN;
+    }
+  }
+  TCPIP_APIMSG_ACK(msg);
+}
+#endif /* LWIP_IGMP */
+
+#if LWIP_DNS
+/**
+ * Callback function that is called when DNS name is resolved
+ * (or on timeout). A waiting application thread is waked up by
+ * signaling the semaphore.
+ */
+static void
+do_dns_found(const char *name, ip_addr_t *ipaddr, void *arg)
+{
+  struct dns_api_msg *msg = (struct dns_api_msg*)arg;
+
+  LWIP_ASSERT("DNS response for wrong host name", strcmp(msg->name, name) == 0);
+  LWIP_UNUSED_ARG(name);
+
+  if (ipaddr == NULL) {
+    /* timeout or memory error */
+    *msg->err = ERR_VAL;
+  } else {
+    /* address was resolved */
+    *msg->err = ERR_OK;
+    *msg->addr = *ipaddr;
+  }
+  /* wake up the application task waiting in netconn_gethostbyname */
+  sys_sem_signal(msg->sem);
+}
+
+/**
+ * Execute a DNS query
+ * Called from netconn_gethostbyname
+ *
+ * @param arg the dns_api_msg pointing to the query
+ */
+void
+do_gethostbyname(void *arg)
+{
+  struct dns_api_msg *msg = (struct dns_api_msg*)arg;
+
+  *msg->err = dns_gethostbyname(msg->name, msg->addr, do_dns_found, msg);
+  if (*msg->err != ERR_INPROGRESS) {
+    /* on error or immediate success, wake up the application
+     * task waiting in netconn_gethostbyname */
+    sys_sem_signal(msg->sem);
+  }
+}
+#endif /* LWIP_DNS */
+
+#endif /* LWIP_NETCONN */
diff --git a/core/lwip/src/api/err.c b/core/lwip/src/api/err.c
new file mode 100644
index 00000000..92fa8b7d
--- /dev/null
+++ b/core/lwip/src/api/err.c
@@ -0,0 +1,75 @@
+/**
+ * @file
+ * Error Management module
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/err.h"
+
+#ifdef LWIP_DEBUG
+
+static const char *err_strerr[] = {
+           "Ok.",                    /* ERR_OK          0  */
+           "Out of memory error.",   /* ERR_MEM        -1  */
+           "Buffer error.",          /* ERR_BUF        -2  */
+           "Timeout.",               /* ERR_TIMEOUT    -3  */
+           "Routing problem.",       /* ERR_RTE        -4  */
+           "Operation in progress.", /* ERR_INPROGRESS -5  */
+           "Illegal value.",         /* ERR_VAL        -6  */
+           "Operation would block.", /* ERR_WOULDBLOCK -7  */
+           "Address in use.",        /* ERR_USE        -8  */
+           "Already connected.",     /* ERR_ISCONN     -9  */
+           "Connection aborted.",    /* ERR_ABRT       -10 */
+           "Connection reset.",      /* ERR_RST        -11 */
+           "Connection closed.",     /* ERR_CLSD       -12 */
+           "Not connected.",         /* ERR_CONN       -13 */
+           "Illegal argument.",      /* ERR_ARG        -14 */
+           "Low-level netif error.", /* ERR_IF         -15 */
+};
+
+/**
+ * Convert an lwip internal error to a string representation.
+ *
+ * @param err an lwip internal err_t
+ * @return a string representation for err
+ */
+const char *
+lwip_strerr(err_t err)
+{
+  return err_strerr[-err];
+
+}
+
+#endif /* LWIP_DEBUG */
diff --git a/core/lwip/src/api/netbuf.c b/core/lwip/src/api/netbuf.c
new file mode 100644
index 00000000..9390c9ee
--- /dev/null
+++ b/core/lwip/src/api/netbuf.c
@@ -0,0 +1,245 @@
+/**
+ * @file
+ * Network buffer management
+ *
+ */
+ 
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_NETCONN /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/netbuf.h"
+#include "lwip/memp.h"
+
+#include <string.h>
+
+/**
+ * Create (allocate) and initialize a new netbuf.
+ * The netbuf doesn't yet contain a packet buffer!
+ *
+ * @return a pointer to a new netbuf
+ *         NULL on lack of memory
+ */
+struct
+netbuf *netbuf_new(void)
+{
+  struct netbuf *buf;
+
+  buf = (struct netbuf *)memp_malloc(MEMP_NETBUF);
+  if (buf != NULL) {
+    buf->p = NULL;
+    buf->ptr = NULL;
+    ip_addr_set_any(&buf->addr);
+    buf->port = 0;
+#if LWIP_NETBUF_RECVINFO || LWIP_CHECKSUM_ON_COPY
+#if LWIP_CHECKSUM_ON_COPY
+    buf->flags = 0;
+#endif /* LWIP_CHECKSUM_ON_COPY */
+    buf->toport_chksum = 0;
+#if LWIP_NETBUF_RECVINFO
+    ip_addr_set_any(&buf->toaddr);
+#endif /* LWIP_NETBUF_RECVINFO */
+#endif /* LWIP_NETBUF_RECVINFO || LWIP_CHECKSUM_ON_COPY */
+    return buf;
+  } else {
+    return NULL;
+  }
+}
+
+/**
+ * Deallocate a netbuf allocated by netbuf_new().
+ *
+ * @param buf pointer to a netbuf allocated by netbuf_new()
+ */
+void
+netbuf_delete(struct netbuf *buf)
+{
+  if (buf != NULL) {
+    if (buf->p != NULL) {
+      pbuf_free(buf->p);
+      buf->p = buf->ptr = NULL;
+    }
+    memp_free(MEMP_NETBUF, buf);
+  }
+}
+
+/**
+ * Allocate memory for a packet buffer for a given netbuf.
+ *
+ * @param buf the netbuf for which to allocate a packet buffer
+ * @param size the size of the packet buffer to allocate
+ * @return pointer to the allocated memory
+ *         NULL if no memory could be allocated
+ */
+void *
+netbuf_alloc(struct netbuf *buf, u16_t size)
+{
+  LWIP_ERROR("netbuf_alloc: invalid buf", (buf != NULL), return NULL;);
+
+  /* Deallocate any previously allocated memory. */
+  if (buf->p != NULL) {
+    pbuf_free(buf->p);
+  }
+  buf->p = pbuf_alloc(PBUF_TRANSPORT, size, PBUF_RAM);
+  if (buf->p == NULL) {
+     return NULL;
+  }
+  LWIP_ASSERT("check that first pbuf can hold size",
+             (buf->p->len >= size));
+  buf->ptr = buf->p;
+  return buf->p->payload;
+}
+
+/**
+ * Free the packet buffer included in a netbuf
+ *
+ * @param buf pointer to the netbuf which contains the packet buffer to free
+ */
+void
+netbuf_free(struct netbuf *buf)
+{
+  LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return;);
+  if (buf->p != NULL) {
+    pbuf_free(buf->p);
+  }
+  buf->p = buf->ptr = NULL;
+}
+
+/**
+ * Let a netbuf reference existing (non-volatile) data.
+ *
+ * @param buf netbuf which should reference the data
+ * @param dataptr pointer to the data to reference
+ * @param size size of the data
+ * @return ERR_OK if data is referenced
+ *         ERR_MEM if data couldn't be referenced due to lack of memory
+ */
+err_t
+netbuf_ref(struct netbuf *buf, const void *dataptr, u16_t size)
+{
+  LWIP_ERROR("netbuf_ref: invalid buf", (buf != NULL), return ERR_ARG;);
+  if (buf->p != NULL) {
+    pbuf_free(buf->p);
+  }
+  buf->p = pbuf_alloc(PBUF_TRANSPORT, 0, PBUF_REF);
+  if (buf->p == NULL) {
+    buf->ptr = NULL;
+    return ERR_MEM;
+  }
+  buf->p->payload = (void*)dataptr;
+  buf->p->len = buf->p->tot_len = size;
+  buf->ptr = buf->p;
+  return ERR_OK;
+}
+
+/**
+ * Chain one netbuf to another (@see pbuf_chain)
+ *
+ * @param head the first netbuf
+ * @param tail netbuf to chain after head, freed by this function, may not be reference after returning
+ */
+void
+netbuf_chain(struct netbuf *head, struct netbuf *tail)
+{
+  LWIP_ERROR("netbuf_ref: invalid head", (head != NULL), return;);
+  LWIP_ERROR("netbuf_chain: invalid tail", (tail != NULL), return;);
+  pbuf_cat(head->p, tail->p);
+  head->ptr = head->p;
+  memp_free(MEMP_NETBUF, tail);
+}
+
+/**
+ * Get the data pointer and length of the data inside a netbuf.
+ *
+ * @param buf netbuf to get the data from
+ * @param dataptr pointer to a void pointer where to store the data pointer
+ * @param len pointer to an u16_t where the length of the data is stored
+ * @return ERR_OK if the information was retreived,
+ *         ERR_BUF on error.
+ */
+err_t
+netbuf_data(struct netbuf *buf, void **dataptr, u16_t *len)
+{
+  LWIP_ERROR("netbuf_data: invalid buf", (buf != NULL), return ERR_ARG;);
+  LWIP_ERROR("netbuf_data: invalid dataptr", (dataptr != NULL), return ERR_ARG;);
+  LWIP_ERROR("netbuf_data: invalid len", (len != NULL), return ERR_ARG;);
+
+  if (buf->ptr == NULL) {
+    return ERR_BUF;
+  }
+  *dataptr = buf->ptr->payload;
+  *len = buf->ptr->len;
+  return ERR_OK;
+}
+
+/**
+ * Move the current data pointer of a packet buffer contained in a netbuf
+ * to the next part.
+ * The packet buffer itself is not modified.
+ *
+ * @param buf the netbuf to modify
+ * @return -1 if there is no next part
+ *         1  if moved to the next part but now there is no next part
+ *         0  if moved to the next part and there are still more parts
+ */
+s8_t
+netbuf_next(struct netbuf *buf)
+{
+  LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return -1;);
+  if (buf->ptr->next == NULL) {
+    return -1;
+  }
+  buf->ptr = buf->ptr->next;
+  if (buf->ptr->next == NULL) {
+    return 1;
+  }
+  return 0;
+}
+
+/**
+ * Move the current data pointer of a packet buffer contained in a netbuf
+ * to the beginning of the packet.
+ * The packet buffer itself is not modified.
+ *
+ * @param buf the netbuf to modify
+ */
+void
+netbuf_first(struct netbuf *buf)
+{
+  LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return;);
+  buf->ptr = buf->p;
+}
+
+#endif /* LWIP_NETCONN */
diff --git a/core/lwip/src/api/netdb.c b/core/lwip/src/api/netdb.c
new file mode 100644
index 00000000..a7e4e06b
--- /dev/null
+++ b/core/lwip/src/api/netdb.c
@@ -0,0 +1,352 @@
+/**
+ * @file
+ * API functions for name resolving
+ *
+ */
+
+/*
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Simon Goldschmidt
+ *
+ */
+
+#include "lwip/netdb.h"
+
+#if LWIP_DNS && LWIP_SOCKET
+
+#include "lwip/err.h"
+#include "lwip/mem.h"
+#include "lwip/memp.h"
+#include "lwip/ip_addr.h"
+#include "lwip/api.h"
+#include "lwip/dns.h"
+
+#include <string.h>
+#include <stdlib.h>
+
+/** helper struct for gethostbyname_r to access the char* buffer */
+struct gethostbyname_r_helper {
+  ip_addr_t *addrs;
+  ip_addr_t addr;
+  char *aliases;
+};
+
+/** h_errno is exported in netdb.h for access by applications. */
+#if LWIP_DNS_API_DECLARE_H_ERRNO
+int h_errno;
+#endif /* LWIP_DNS_API_DECLARE_H_ERRNO */
+
+/** define "hostent" variables storage: 0 if we use a static (but unprotected)
+ * set of variables for lwip_gethostbyname, 1 if we use a local storage */
+#ifndef LWIP_DNS_API_HOSTENT_STORAGE
+#define LWIP_DNS_API_HOSTENT_STORAGE 0
+#endif
+
+/** define "hostent" variables storage */
+#if LWIP_DNS_API_HOSTENT_STORAGE
+#define HOSTENT_STORAGE
+#else
+#define HOSTENT_STORAGE static
+#endif /* LWIP_DNS_API_STATIC_HOSTENT */
+
+/**
+ * Returns an entry containing addresses of address family AF_INET
+ * for the host with name name.
+ * Due to dns_gethostbyname limitations, only one address is returned.
+ *
+ * @param name the hostname to resolve
+ * @return an entry containing addresses of address family AF_INET
+ *         for the host with name name
+ */
+struct hostent*
+lwip_gethostbyname(const char *name)
+{
+  err_t err;
+  ip_addr_t addr;
+
+  /* buffer variables for lwip_gethostbyname() */
+  HOSTENT_STORAGE struct hostent s_hostent;
+  HOSTENT_STORAGE char *s_aliases;
+  HOSTENT_STORAGE ip_addr_t s_hostent_addr;
+  HOSTENT_STORAGE ip_addr_t *s_phostent_addr[2];
+
+  /* query host IP address */
+  err = netconn_gethostbyname(name, &addr);
+  if (err != ERR_OK) {
+    LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err));
+    h_errno = HOST_NOT_FOUND;
+    return NULL;
+  }
+
+  /* fill hostent */
+  s_hostent_addr = addr;
+  s_phostent_addr[0] = &s_hostent_addr;
+  s_phostent_addr[1] = NULL;
+  s_hostent.h_name = (char*)name;
+  s_hostent.h_aliases = &s_aliases;
+  s_hostent.h_addrtype = AF_INET;
+  s_hostent.h_length = sizeof(ip_addr_t);
+  s_hostent.h_addr_list = (char**)&s_phostent_addr;
+
+#if DNS_DEBUG
+  /* dump hostent */
+  LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_name           == %s\n", s_hostent.h_name));
+  LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases        == %p\n", s_hostent.h_aliases));
+  if (s_hostent.h_aliases != NULL) {
+    u8_t idx;
+    for ( idx=0; s_hostent.h_aliases[idx]; idx++) {
+      LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases[%i]->   == %p\n", idx, s_hostent.h_aliases[idx]));
+      LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases[%i]->   == %s\n", idx, s_hostent.h_aliases[idx]));
+    }
+  }
+  LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addrtype       == %d\n", s_hostent.h_addrtype));
+  LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_length         == %d\n", s_hostent.h_length));
+  LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list      == %p\n", s_hostent.h_addr_list));
+  if (s_hostent.h_addr_list != NULL) {
+    u8_t idx;
+    for ( idx=0; s_hostent.h_addr_list[idx]; idx++) {
+      LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list[%i]   == %p\n", idx, s_hostent.h_addr_list[idx]));
+      LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list[%i]-> == %s\n", idx, ip_ntoa((ip_addr_t*)s_hostent.h_addr_list[idx])));
+    }
+  }
+#endif /* DNS_DEBUG */
+
+#if LWIP_DNS_API_HOSTENT_STORAGE
+  /* this function should return the "per-thread" hostent after copy from s_hostent */
+  return sys_thread_hostent(&s_hostent);
+#else
+  return &s_hostent;
+#endif /* LWIP_DNS_API_HOSTENT_STORAGE */
+}
+
+/**
+ * Thread-safe variant of lwip_gethostbyname: instead of using a static
+ * buffer, this function takes buffer and errno pointers as arguments
+ * and uses these for the result.
+ *
+ * @param name the hostname to resolve
+ * @param ret pre-allocated struct where to store the result
+ * @param buf pre-allocated buffer where to store additional data
+ * @param buflen the size of buf
+ * @param result pointer to a hostent pointer that is set to ret on success
+ *               and set to zero on error
+ * @param h_errnop pointer to an int where to store errors (instead of modifying
+ *                 the global h_errno)
+ * @return 0 on success, non-zero on error, additional error information
+ *         is stored in *h_errnop instead of h_errno to be thread-safe
+ */
+int
+lwip_gethostbyname_r(const char *name, struct hostent *ret, char *buf,
+                size_t buflen, struct hostent **result, int *h_errnop)
+{
+  err_t err;
+  struct gethostbyname_r_helper *h;
+  char *hostname;
+  size_t namelen;
+  int lh_errno;
+
+  if (h_errnop == NULL) {
+    /* ensure h_errnop is never NULL */
+    h_errnop = &lh_errno;
+  }
+
+  if (result == NULL) {
+    /* not all arguments given */
+    *h_errnop = EINVAL;
+    return -1;
+  }
+  /* first thing to do: set *result to nothing */
+  *result = NULL;
+  if ((name == NULL) || (ret == NULL) || (buf == 0)) {
+    /* not all arguments given */
+    *h_errnop = EINVAL;
+    return -1;
+  }
+
+  namelen = strlen(name);
+  if (buflen < (sizeof(struct gethostbyname_r_helper) + namelen + 1 + (MEM_ALIGNMENT - 1))) {
+    /* buf can't hold the data needed + a copy of name */
+    *h_errnop = ERANGE;
+    return -1;
+  }
+
+  h = (struct gethostbyname_r_helper*)LWIP_MEM_ALIGN(buf);
+  hostname = ((char*)h) + sizeof(struct gethostbyname_r_helper);
+
+  /* query host IP address */
+  err = netconn_gethostbyname(name, &(h->addr));
+  if (err != ERR_OK) {
+    LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err));
+    *h_errnop = ENSRNOTFOUND;
+    return -1;
+  }
+
+  /* copy the hostname into buf */
+  MEMCPY(hostname, name, namelen);
+  hostname[namelen] = 0;
+
+  /* fill hostent */
+  h->addrs = &(h->addr);
+  h->aliases = NULL;
+  ret->h_name = (char*)hostname;
+  ret->h_aliases = &(h->aliases);
+  ret->h_addrtype = AF_INET;
+  ret->h_length = sizeof(ip_addr_t);
+  ret->h_addr_list = (char**)&(h->addrs);
+
+  /* set result != NULL */
+  *result = ret;
+
+  /* return success */
+  return 0;
+}
+
+/**
+ * Frees one or more addrinfo structures returned by getaddrinfo(), along with
+ * any additional storage associated with those structures. If the ai_next field
+ * of the structure is not null, the entire list of structures is freed.
+ *
+ * @param ai struct addrinfo to free
+ */
+void
+lwip_freeaddrinfo(struct addrinfo *ai)
+{
+  struct addrinfo *next;
+
+  while (ai != NULL) {
+    next = ai->ai_next;
+    memp_free(MEMP_NETDB, ai);
+    ai = next;
+  }
+}
+
+/**
+ * Translates the name of a service location (for example, a host name) and/or
+ * a service name and returns a set of socket addresses and associated
+ * information to be used in creating a socket with which to address the
+ * specified service.
+ * Memory for the result is allocated internally and must be freed by calling
+ * lwip_freeaddrinfo()!
+ *
+ * Due to a limitation in dns_gethostbyname, only the first address of a
+ * host is returned.
+ * Also, service names are not supported (only port numbers)!
+ *
+ * @param nodename descriptive name or address string of the host
+ *                 (may be NULL -> local address)
+ * @param servname port number as string of NULL 
+ * @param hints structure containing input values that set socktype and protocol
+ * @param res pointer to a pointer where to store the result (set to NULL on failure)
+ * @return 0 on success, non-zero on failure
+ */
+int
+lwip_getaddrinfo(const char *nodename, const char *servname,
+       const struct addrinfo *hints, struct addrinfo **res)
+{
+  err_t err;
+  ip_addr_t addr;
+  struct addrinfo *ai;
+  struct sockaddr_in *sa = NULL;
+  int port_nr = 0;
+  size_t total_size;
+  size_t namelen = 0;
+
+  if (res == NULL) {
+    return EAI_FAIL;
+  }
+  *res = NULL;
+  if ((nodename == NULL) && (servname == NULL)) {
+    return EAI_NONAME;
+  }
+
+  if (servname != NULL) {
+    /* service name specified: convert to port number
+     * @todo?: currently, only ASCII integers (port numbers) are supported! */
+    port_nr = atoi(servname);
+    if ((port_nr <= 0) || (port_nr > 0xffff)) {
+      return EAI_SERVICE;
+    }
+  }
+
+  if (nodename != NULL) {
+    /* service location specified, try to resolve */
+    err = netconn_gethostbyname(nodename, &addr);
+    if (err != ERR_OK) {
+      return EAI_FAIL;
+    }
+  } else {
+    /* service location specified, use loopback address */
+    ip_addr_set_loopback(&addr);
+  }
+
+  total_size = sizeof(struct addrinfo) + sizeof(struct sockaddr_in);
+  if (nodename != NULL) {
+    namelen = strlen(nodename);
+    LWIP_ASSERT("namelen is too long", (namelen + 1) <= (mem_size_t)-1);
+    total_size += namelen + 1;
+  }
+  /* If this fails, please report to lwip-devel! :-) */
+  LWIP_ASSERT("total_size <= NETDB_ELEM_SIZE: please report this!",
+    total_size <= NETDB_ELEM_SIZE);
+  ai = (struct addrinfo *)memp_malloc(MEMP_NETDB);
+  if (ai == NULL) {
+    goto memerr;
+  }
+  memset(ai, 0, total_size);
+  sa = (struct sockaddr_in*)((u8_t*)ai + sizeof(struct addrinfo));
+  /* set up sockaddr */
+  inet_addr_from_ipaddr(&sa->sin_addr, &addr);
+  sa->sin_family = AF_INET;
+  sa->sin_len = sizeof(struct sockaddr_in);
+  sa->sin_port = htons((u16_t)port_nr);
+
+  /* set up addrinfo */
+  ai->ai_family = AF_INET;
+  if (hints != NULL) {
+    /* copy socktype & protocol from hints if specified */
+    ai->ai_socktype = hints->ai_socktype;
+    ai->ai_protocol = hints->ai_protocol;
+  }
+  if (nodename != NULL) {
+    /* copy nodename to canonname if specified */
+    ai->ai_canonname = ((char*)ai + sizeof(struct addrinfo) + sizeof(struct sockaddr_in));
+    MEMCPY(ai->ai_canonname, nodename, namelen);
+    ai->ai_canonname[namelen] = 0;
+  }
+  ai->ai_addrlen = sizeof(struct sockaddr_in);
+  ai->ai_addr = (struct sockaddr*)sa;
+
+  *res = ai;
+
+  return 0;
+memerr:
+  if (ai != NULL) {
+    memp_free(MEMP_NETDB, ai);
+  }
+  return EAI_MEMORY;
+}
+
+#endif /* LWIP_DNS && LWIP_SOCKET */
diff --git a/core/lwip/src/api/netifapi.c b/core/lwip/src/api/netifapi.c
new file mode 100644
index 00000000..43e47203
--- /dev/null
+++ b/core/lwip/src/api/netifapi.c
@@ -0,0 +1,160 @@
+/**
+ * @file
+ * Network Interface Sequential API module
+ *
+ */
+
+/*
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_NETIF_API /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/netifapi.h"
+#include "lwip/tcpip.h"
+
+/**
+ * Call netif_add() inside the tcpip_thread context.
+ */
+void
+do_netifapi_netif_add(struct netifapi_msg_msg *msg)
+{
+  if (!netif_add( msg->netif,
+                  msg->msg.add.ipaddr,
+                  msg->msg.add.netmask,
+                  msg->msg.add.gw,
+                  msg->msg.add.state,
+                  msg->msg.add.init,
+                  msg->msg.add.input)) {
+    msg->err = ERR_IF;
+  } else {
+    msg->err = ERR_OK;
+  }
+  TCPIP_NETIFAPI_ACK(msg);
+}
+
+/**
+ * Call netif_set_addr() inside the tcpip_thread context.
+ */
+void
+do_netifapi_netif_set_addr(struct netifapi_msg_msg *msg)
+{
+  netif_set_addr( msg->netif,
+                  msg->msg.add.ipaddr,
+                  msg->msg.add.netmask,
+                  msg->msg.add.gw);
+  msg->err = ERR_OK;
+  TCPIP_NETIFAPI_ACK(msg);
+}
+
+/**
+ * Call the "errtfunc" (or the "voidfunc" if "errtfunc" is NULL) inside the
+ * tcpip_thread context.
+ */
+void
+do_netifapi_netif_common(struct netifapi_msg_msg *msg)
+{
+  if (msg->msg.common.errtfunc != NULL) {
+    msg->err = msg->msg.common.errtfunc(msg->netif);
+  } else {
+    msg->err = ERR_OK;
+    msg->msg.common.voidfunc(msg->netif);
+  }
+  TCPIP_NETIFAPI_ACK(msg);
+}
+
+/**
+ * Call netif_add() in a thread-safe way by running that function inside the
+ * tcpip_thread context.
+ *
+ * @note for params @see netif_add()
+ */
+err_t
+netifapi_netif_add(struct netif *netif,
+                   ip_addr_t *ipaddr,
+                   ip_addr_t *netmask,
+                   ip_addr_t *gw,
+                   void *state,
+                   netif_init_fn init,
+                   netif_input_fn input)
+{
+  struct netifapi_msg msg;
+  msg.function = do_netifapi_netif_add;
+  msg.msg.netif = netif;
+  msg.msg.msg.add.ipaddr  = ipaddr;
+  msg.msg.msg.add.netmask = netmask;
+  msg.msg.msg.add.gw      = gw;
+  msg.msg.msg.add.state   = state;
+  msg.msg.msg.add.init    = init;
+  msg.msg.msg.add.input   = input;
+  TCPIP_NETIFAPI(&msg);
+  return msg.msg.err;
+}
+
+/**
+ * Call netif_set_addr() in a thread-safe way by running that function inside the
+ * tcpip_thread context.
+ *
+ * @note for params @see netif_set_addr()
+ */
+err_t
+netifapi_netif_set_addr(struct netif *netif,
+                        ip_addr_t *ipaddr,
+                        ip_addr_t *netmask,
+                        ip_addr_t *gw)
+{
+  struct netifapi_msg msg;
+  msg.function = do_netifapi_netif_set_addr;
+  msg.msg.netif = netif;
+  msg.msg.msg.add.ipaddr  = ipaddr;
+  msg.msg.msg.add.netmask = netmask;
+  msg.msg.msg.add.gw      = gw;
+  TCPIP_NETIFAPI(&msg);
+  return msg.msg.err;
+}
+
+/**
+ * call the "errtfunc" (or the "voidfunc" if "errtfunc" is NULL) in a thread-safe
+ * way by running that function inside the tcpip_thread context.
+ *
+ * @note use only for functions where there is only "netif" parameter.
+ */
+err_t
+netifapi_netif_common(struct netif *netif, netifapi_void_fn voidfunc,
+                       netifapi_errt_fn errtfunc)
+{
+  struct netifapi_msg msg;
+  msg.function = do_netifapi_netif_common;
+  msg.msg.netif = netif;
+  msg.msg.msg.common.voidfunc = voidfunc;
+  msg.msg.msg.common.errtfunc = errtfunc;
+  TCPIP_NETIFAPI(&msg);
+  return msg.msg.err;
+}
+
+#endif /* LWIP_NETIF_API */
diff --git a/core/lwip/src/api/sockets.c b/core/lwip/src/api/sockets.c
new file mode 100644
index 00000000..e36012ce
--- /dev/null
+++ b/core/lwip/src/api/sockets.c
@@ -0,0 +1,2347 @@
+/**
+ * @file
+ * Sockets BSD-Like API module
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ * Improved by Marc Boucher <marc@mbsi.ca> and David Haas <dhaas@alum.rpi.edu>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_SOCKET /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/sockets.h"
+#include "lwip/api.h"
+#include "lwip/sys.h"
+#include "lwip/igmp.h"
+#include "lwip/inet.h"
+#include "lwip/tcp.h"
+#include "lwip/raw.h"
+#include "lwip/udp.h"
+#include "lwip/tcpip.h"
+#include "lwip/pbuf.h"
+#if LWIP_CHECKSUM_ON_COPY
+#include "lwip/inet_chksum.h"
+#endif
+
+#include <string.h>
+
+#define NUM_SOCKETS MEMP_NUM_NETCONN
+
+/** Contains all internal pointers and states used for a socket */
+struct lwip_sock {
+  /** sockets currently are built on netconns, each socket has one netconn */
+  struct netconn *conn;
+  /** data that was left from the previous read */
+  void *lastdata;
+  /** offset in the data that was left from the previous read */
+  u16_t lastoffset;
+  /** number of times data was received, set by event_callback(),
+      tested by the receive and select functions */
+  s16_t rcvevent;
+  /** number of times data was ACKed (free send buffer), set by event_callback(),
+      tested by select */
+  u16_t sendevent;
+  /** error happened for this socket, set by event_callback(), tested by select */
+  u16_t errevent; 
+  /** last error that occurred on this socket */
+  int err;
+  /** counter of how many threads are waiting for this socket using select */
+  int select_waiting;
+};
+
+/** Description for a task waiting in select */
+struct lwip_select_cb {
+  /** Pointer to the next waiting task */
+  struct lwip_select_cb *next;
+  /** Pointer to the previous waiting task */
+  struct lwip_select_cb *prev;
+  /** readset passed to select */
+  fd_set *readset;
+  /** writeset passed to select */
+  fd_set *writeset;
+  /** unimplemented: exceptset passed to select */
+  fd_set *exceptset;
+  /** don't signal the same semaphore twice: set to 1 when signalled */
+  int sem_signalled;
+  /** semaphore to wake up a task waiting for select */
+  sys_sem_t sem;
+};
+
+/** This struct is used to pass data to the set/getsockopt_internal
+ * functions running in tcpip_thread context (only a void* is allowed) */
+struct lwip_setgetsockopt_data {
+  /** socket struct for which to change options */
+  struct lwip_sock *sock;
+#ifdef LWIP_DEBUG
+  /** socket index for which to change options */
+  int s;
+#endif /* LWIP_DEBUG */
+  /** level of the option to process */
+  int level;
+  /** name of the option to process */
+  int optname;
+  /** set: value to set the option to
+    * get: value of the option is stored here */
+  void *optval;
+  /** size of *optval */
+  socklen_t *optlen;
+  /** if an error occures, it is temporarily stored here */
+  err_t err;
+};
+
+/** The global array of available sockets */
+static struct lwip_sock sockets[NUM_SOCKETS];
+/** The global list of tasks waiting for select */
+static struct lwip_select_cb *select_cb_list;
+/** This counter is increased from lwip_select when the list is chagned
+    and checked in event_callback to see if it has changed. */
+static volatile int select_cb_ctr;
+
+/** Table to quickly map an lwIP error (err_t) to a socket error
+  * by using -err as an index */
+static const int err_to_errno_table[] = {
+  0,             /* ERR_OK          0      No error, everything OK. */
+  ENOMEM,        /* ERR_MEM        -1      Out of memory error.     */
+  ENOBUFS,       /* ERR_BUF        -2      Buffer error.            */
+  EWOULDBLOCK,   /* ERR_TIMEOUT    -3      Timeout                  */
+  EHOSTUNREACH,  /* ERR_RTE        -4      Routing problem.         */
+  EINPROGRESS,   /* ERR_INPROGRESS -5      Operation in progress    */
+  EINVAL,        /* ERR_VAL        -6      Illegal value.           */
+  EWOULDBLOCK,   /* ERR_WOULDBLOCK -7      Operation would block.   */
+  EADDRINUSE,    /* ERR_USE        -8      Address in use.          */
+  EALREADY,      /* ERR_ISCONN     -9      Already connected.       */
+  ECONNABORTED,  /* ERR_ABRT       -10     Connection aborted.      */
+  ECONNRESET,    /* ERR_RST        -11     Connection reset.        */
+  ENOTCONN,      /* ERR_CLSD       -12     Connection closed.       */
+  ENOTCONN,      /* ERR_CONN       -13     Not connected.           */
+  EIO,           /* ERR_ARG        -14     Illegal argument.        */
+  -1,            /* ERR_IF         -15     Low-level netif error    */
+};
+
+#define ERR_TO_ERRNO_TABLE_SIZE \
+  (sizeof(err_to_errno_table)/sizeof(err_to_errno_table[0]))
+
+#define err_to_errno(err) \
+  ((unsigned)(-(err)) < ERR_TO_ERRNO_TABLE_SIZE ? \
+    err_to_errno_table[-(err)] : EIO)
+
+#ifdef ERRNO
+#ifndef set_errno
+#define set_errno(err) errno = (err)
+#endif
+#else /* ERRNO */
+#define set_errno(err)
+#endif /* ERRNO */
+
+#define sock_set_errno(sk, e) do { \
+  sk->err = (e); \
+  set_errno(sk->err); \
+} while (0)
+
+/* Forward delcaration of some functions */
+static void event_callback(struct netconn *conn, enum netconn_evt evt, u16_t len);
+static void lwip_getsockopt_internal(void *arg);
+static void lwip_setsockopt_internal(void *arg);
+
+/**
+ * Initialize this module. This function has to be called before any other
+ * functions in this module!
+ */
+void
+lwip_socket_init(void)
+{
+}
+
+/**
+ * Map a externally used socket index to the internal socket representation.
+ *
+ * @param s externally used socket index
+ * @return struct lwip_sock for the socket or NULL if not found
+ */
+static struct lwip_sock *
+get_socket(int s)
+{
+  struct lwip_sock *sock;
+
+  if ((s < 0) || (s >= NUM_SOCKETS)) {
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("get_socket(%d): invalid\n", s));
+    set_errno(EBADF);
+    return NULL;
+  }
+
+  sock = &sockets[s];
+
+  if (!sock->conn) {
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("get_socket(%d): not active\n", s));
+    set_errno(EBADF);
+    return NULL;
+  }
+
+  return sock;
+}
+
+/**
+ * Same as get_socket but doesn't set errno
+ *
+ * @param s externally used socket index
+ * @return struct lwip_sock for the socket or NULL if not found
+ */
+static struct lwip_sock *
+tryget_socket(int s)
+{
+  if ((s < 0) || (s >= NUM_SOCKETS)) {
+    return NULL;
+  }
+  if (!sockets[s].conn) {
+    return NULL;
+  }
+  return &sockets[s];
+}
+
+/**
+ * Allocate a new socket for a given netconn.
+ *
+ * @param newconn the netconn for which to allocate a socket
+ * @param accepted 1 if socket has been created by accept(),
+ *                 0 if socket has been created by socket()
+ * @return the index of the new socket; -1 on error
+ */
+static int
+alloc_socket(struct netconn *newconn, int accepted)
+{
+  int i;
+  SYS_ARCH_DECL_PROTECT(lev);
+
+  /* allocate a new socket identifier */
+  for (i = 0; i < NUM_SOCKETS; ++i) {
+    /* Protect socket array */
+    SYS_ARCH_PROTECT(lev);
+    if (!sockets[i].conn) {
+      sockets[i].conn       = newconn;
+      /* The socket is not yet known to anyone, so no need to protect
+         after having marked it as used. */
+      SYS_ARCH_UNPROTECT(lev);
+      sockets[i].lastdata   = NULL;
+      sockets[i].lastoffset = 0;
+      sockets[i].rcvevent   = 0;
+      /* TCP sendbuf is empty, but the socket is not yet writable until connected
+       * (unless it has been created by accept()). */
+      sockets[i].sendevent  = (newconn->type == NETCONN_TCP ? (accepted != 0) : 1);
+      sockets[i].errevent   = 0;
+      sockets[i].err        = 0;
+      sockets[i].select_waiting = 0;
+      return i;
+    }
+    SYS_ARCH_UNPROTECT(lev);
+  }
+  return -1;
+}
+
+/** Free a socket. The socket's netconn must have been
+ * delete before!
+ *
+ * @param sock the socket to free
+ * @param is_tcp != 0 for TCP sockets, used to free lastdata
+ */
+static void
+free_socket(struct lwip_sock *sock, int is_tcp)
+{
+  void *lastdata;
+  SYS_ARCH_DECL_PROTECT(lev);
+
+  lastdata         = sock->lastdata;
+  sock->lastdata   = NULL;
+  sock->lastoffset = 0;
+  sock->err        = 0;
+
+  /* Protect socket array */
+  SYS_ARCH_PROTECT(lev);
+  sock->conn       = NULL;
+  SYS_ARCH_UNPROTECT(lev);
+  /* don't use 'sock' after this line, as another task might have allocated it */
+
+  if (lastdata != NULL) {
+    if (is_tcp) {
+      pbuf_free((struct pbuf *)lastdata);
+    } else {
+      netbuf_delete((struct netbuf *)lastdata);
+    }
+  }
+}
+
+/* Below this, the well-known socket functions are implemented.
+ * Use google.com or opengroup.org to get a good description :-)
+ *
+ * Exceptions are documented!
+ */
+
+int
+lwip_accept(int s, struct sockaddr *addr, socklen_t *addrlen)
+{
+  struct lwip_sock *sock, *nsock;
+  struct netconn *newconn;
+  ip_addr_t naddr;
+  u16_t port;
+  int newsock;
+  struct sockaddr_in sin;
+  err_t err;
+  SYS_ARCH_DECL_PROTECT(lev);
+
+  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d)...\n", s));
+  sock = get_socket(s);
+  if (!sock) {
+    return -1;
+  }
+
+  if (netconn_is_nonblocking(sock->conn) && (sock->rcvevent <= 0)) {
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d): returning EWOULDBLOCK\n", s));
+    sock_set_errno(sock, EWOULDBLOCK);
+    return -1;
+  }
+
+  /* wait for a new connection */
+  err = netconn_accept(sock->conn, &newconn);
+  if (err != ERR_OK) {
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d): netconn_acept failed, err=%d\n", s, err));
+    sock_set_errno(sock, err_to_errno(err));
+    return -1;
+  }
+  LWIP_ASSERT("newconn != NULL", newconn != NULL);
+  /* Prevent automatic window updates, we do this on our own! */
+  netconn_set_noautorecved(newconn, 1);
+
+  /* get the IP address and port of the remote host */
+  err = netconn_peer(newconn, &naddr, &port);
+  if (err != ERR_OK) {
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d): netconn_peer failed, err=%d\n", s, err));
+    netconn_delete(newconn);
+    sock_set_errno(sock, err_to_errno(err));
+    return -1;
+  }
+
+  /* Note that POSIX only requires us to check addr is non-NULL. addrlen must
+   * not be NULL if addr is valid.
+   */
+  if (NULL != addr) {
+    LWIP_ASSERT("addr valid but addrlen NULL", addrlen != NULL);
+    memset(&sin, 0, sizeof(sin));
+    sin.sin_len = sizeof(sin);
+    sin.sin_family = AF_INET;
+    sin.sin_port = htons(port);
+    inet_addr_from_ipaddr(&sin.sin_addr, &naddr);
+
+    if (*addrlen > sizeof(sin))
+      *addrlen = sizeof(sin);
+
+    MEMCPY(addr, &sin, *addrlen);
+  }
+
+  newsock = alloc_socket(newconn, 1);
+  if (newsock == -1) {
+    netconn_delete(newconn);
+    sock_set_errno(sock, ENFILE);
+    return -1;
+  }
+  LWIP_ASSERT("invalid socket index", (newsock >= 0) && (newsock < NUM_SOCKETS));
+  LWIP_ASSERT("newconn->callback == event_callback", newconn->callback == event_callback);
+  nsock = &sockets[newsock];
+
+  /* See event_callback: If data comes in right away after an accept, even
+   * though the server task might not have created a new socket yet.
+   * In that case, newconn->socket is counted down (newconn->socket--),
+   * so nsock->rcvevent is >= 1 here!
+   */
+  SYS_ARCH_PROTECT(lev);
+  nsock->rcvevent += (s16_t)(-1 - newconn->socket);
+  newconn->socket = newsock;
+  SYS_ARCH_UNPROTECT(lev);
+
+  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d) returning new sock=%d addr=", s, newsock));
+  ip_addr_debug_print(SOCKETS_DEBUG, &naddr);
+  LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F"\n", port));
+
+  sock_set_errno(sock, 0);
+  return newsock;
+}
+
+int
+lwip_bind(int s, const struct sockaddr *name, socklen_t namelen)
+{
+  struct lwip_sock *sock;
+  ip_addr_t local_addr;
+  u16_t local_port;
+  err_t err;
+  const struct sockaddr_in *name_in;
+
+  sock = get_socket(s);
+  if (!sock) {
+    return -1;
+  }
+
+  /* check size, familiy and alignment of 'name' */
+  LWIP_ERROR("lwip_bind: invalid address", ((namelen == sizeof(struct sockaddr_in)) &&
+             ((name->sa_family) == AF_INET) && ((((mem_ptr_t)name) % 4) == 0)),
+             sock_set_errno(sock, err_to_errno(ERR_ARG)); return -1;);
+  name_in = (const struct sockaddr_in *)(void*)name;
+
+  inet_addr_to_ipaddr(&local_addr, &name_in->sin_addr);
+  local_port = name_in->sin_port;
+
+  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_bind(%d, addr=", s));
+  ip_addr_debug_print(SOCKETS_DEBUG, &local_addr);
+  LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F")\n", ntohs(local_port)));
+
+  err = netconn_bind(sock->conn, &local_addr, ntohs(local_port));
+
+  if (err != ERR_OK) {
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_bind(%d) failed, err=%d\n", s, err));
+    sock_set_errno(sock, err_to_errno(err));
+    return -1;
+  }
+
+  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_bind(%d) succeeded\n", s));
+  sock_set_errno(sock, 0);
+  return 0;
+}
+
+int
+lwip_close(int s)
+{
+  struct lwip_sock *sock;
+  int is_tcp = 0;
+
+  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_close(%d)\n", s));
+
+  sock = get_socket(s);
+  if (!sock) {
+    return -1;
+  }
+
+  if(sock->conn != NULL) {
+    is_tcp = netconn_type(sock->conn) == NETCONN_TCP;
+  } else {
+    LWIP_ASSERT("sock->lastdata == NULL", sock->lastdata == NULL);
+  }
+
+  netconn_delete(sock->conn);
+
+  free_socket(sock, is_tcp);
+  set_errno(0);
+  return 0;
+}
+
+int
+lwip_connect(int s, const struct sockaddr *name, socklen_t namelen)
+{
+  struct lwip_sock *sock;
+  err_t err;
+  const struct sockaddr_in *name_in;
+
+  sock = get_socket(s);
+  if (!sock) {
+    return -1;
+  }
+
+  /* check size, familiy and alignment of 'name' */
+  LWIP_ERROR("lwip_connect: invalid address", ((namelen == sizeof(struct sockaddr_in)) &&
+             ((name->sa_family) == AF_INET) && ((((mem_ptr_t)name) % 4) == 0)),
+             sock_set_errno(sock, err_to_errno(ERR_ARG)); return -1;);
+  name_in = (const struct sockaddr_in *)(void*)name;
+
+  if (name_in->sin_family == AF_UNSPEC) {
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_connect(%d, AF_UNSPEC)\n", s));
+    err = netconn_disconnect(sock->conn);
+  } else {
+    ip_addr_t remote_addr;
+    u16_t remote_port;
+
+    inet_addr_to_ipaddr(&remote_addr, &name_in->sin_addr);
+    remote_port = name_in->sin_port;
+
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_connect(%d, addr=", s));
+    ip_addr_debug_print(SOCKETS_DEBUG, &remote_addr);
+    LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F")\n", ntohs(remote_port)));
+
+    err = netconn_connect(sock->conn, &remote_addr, ntohs(remote_port));
+  }
+
+  if (err != ERR_OK) {
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_connect(%d) failed, err=%d\n", s, err));
+    sock_set_errno(sock, err_to_errno(err));
+    return -1;
+  }
+
+  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_connect(%d) succeeded\n", s));
+  sock_set_errno(sock, 0);
+  return 0;
+}
+
+/**
+ * Set a socket into listen mode.
+ * The socket may not have been used for another connection previously.
+ *
+ * @param s the socket to set to listening mode
+ * @param backlog (ATTENTION: needs TCP_LISTEN_BACKLOG=1)
+ * @return 0 on success, non-zero on failure
+ */
+int
+lwip_listen(int s, int backlog)
+{
+  struct lwip_sock *sock;
+  err_t err;
+
+  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_listen(%d, backlog=%d)\n", s, backlog));
+
+  sock = get_socket(s);
+  if (!sock) {
+    return -1;
+  }
+
+  /* limit the "backlog" parameter to fit in an u8_t */
+  backlog = LWIP_MIN(LWIP_MAX(backlog, 0), 0xff);
+
+  err = netconn_listen_with_backlog(sock->conn, (u8_t)backlog);
+
+  if (err != ERR_OK) {
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_listen(%d) failed, err=%d\n", s, err));
+    sock_set_errno(sock, err_to_errno(err));
+    return -1;
+  }
+
+  sock_set_errno(sock, 0);
+  return 0;
+}
+
+int
+lwip_recvfrom(int s, void *mem, size_t len, int flags,
+        struct sockaddr *from, socklen_t *fromlen)
+{
+  struct lwip_sock *sock;
+  void             *buf = NULL;
+  struct pbuf      *p;
+  u16_t            buflen, copylen;
+  int              off = 0;
+  ip_addr_t        *addr;
+  u16_t            port;
+  u8_t             done = 0;
+  err_t            err;
+
+  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom(%d, %p, %"SZT_F", 0x%x, ..)\n", s, mem, len, flags));
+  sock = get_socket(s);
+  if (!sock) {
+    return -1;
+  }
+
+  do {
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom: top while sock->lastdata=%p\n", sock->lastdata));
+    /* Check if there is data left from the last recv operation. */
+    if (sock->lastdata) {
+      buf = sock->lastdata;
+    } else {
+      /* If this is non-blocking call, then check first */
+      if (((flags & MSG_DONTWAIT) || netconn_is_nonblocking(sock->conn)) && 
+          (sock->rcvevent <= 0)) {
+        if (off > 0) {
+          /* update receive window */
+          netconn_recved(sock->conn, (u32_t)off);
+          /* already received data, return that */
+          sock_set_errno(sock, 0);
+          return off;
+        }
+        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom(%d): returning EWOULDBLOCK\n", s));
+        sock_set_errno(sock, EWOULDBLOCK);
+        return -1;
+      }
+
+      /* No data was left from the previous operation, so we try to get
+         some from the network. */
+      if (netconn_type(sock->conn) == NETCONN_TCP) {
+        err = netconn_recv_tcp_pbuf(sock->conn, (struct pbuf **)&buf);
+      } else {
+        err = netconn_recv(sock->conn, (struct netbuf **)&buf);
+      }
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom: netconn_recv err=%d, netbuf=%p\n",
+        err, buf));
+
+      if (err != ERR_OK) {
+        if (off > 0) {
+          /* update receive window */
+          netconn_recved(sock->conn, (u32_t)off);
+          /* already received data, return that */
+          sock_set_errno(sock, 0);
+          return off;
+        }
+        /* We should really do some error checking here. */
+        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom(%d): buf == NULL, error is \"%s\"!\n",
+          s, lwip_strerr(err)));
+        sock_set_errno(sock, err_to_errno(err));
+        if (err == ERR_CLSD) {
+          return 0;
+        } else {
+          return -1;
+        }
+      }
+      LWIP_ASSERT("buf != NULL", buf != NULL);
+      sock->lastdata = buf;
+    }
+
+    if (netconn_type(sock->conn) == NETCONN_TCP) {
+      p = (struct pbuf *)buf;
+    } else {
+      p = ((struct netbuf *)buf)->p;
+    }
+    buflen = p->tot_len;
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom: buflen=%"U16_F" len=%"SZT_F" off=%d sock->lastoffset=%"U16_F"\n",
+      buflen, len, off, sock->lastoffset));
+
+    buflen -= sock->lastoffset;
+
+    if (len > buflen) {
+      copylen = buflen;
+    } else {
+      copylen = (u16_t)len;
+    }
+
+    /* copy the contents of the received buffer into
+    the supplied memory pointer mem */
+    pbuf_copy_partial(p, (u8_t*)mem + off, copylen, sock->lastoffset);
+
+    off += copylen;
+
+    if (netconn_type(sock->conn) == NETCONN_TCP) {
+      LWIP_ASSERT("invalid copylen, len would underflow", len >= copylen);
+      len -= copylen;
+      if ( (len <= 0) || 
+           (p->flags & PBUF_FLAG_PUSH) || 
+           (sock->rcvevent <= 0) || 
+           ((flags & MSG_PEEK)!=0)) {
+        done = 1;
+      }
+    } else {
+      done = 1;
+    }
+
+    /* Check to see from where the data was.*/
+    if (done) {
+      ip_addr_t fromaddr;
+      if (from && fromlen) {
+        struct sockaddr_in sin;
+
+        if (netconn_type(sock->conn) == NETCONN_TCP) {
+          addr = &fromaddr;
+          netconn_getaddr(sock->conn, addr, &port, 0);
+        } else {
+          addr = netbuf_fromaddr((struct netbuf *)buf);
+          port = netbuf_fromport((struct netbuf *)buf);
+        }
+
+        memset(&sin, 0, sizeof(sin));
+        sin.sin_len = sizeof(sin);
+        sin.sin_family = AF_INET;
+        sin.sin_port = htons(port);
+        inet_addr_from_ipaddr(&sin.sin_addr, addr);
+
+        if (*fromlen > sizeof(sin)) {
+          *fromlen = sizeof(sin);
+        }
+
+        MEMCPY(from, &sin, *fromlen);
+
+        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom(%d): addr=", s));
+        ip_addr_debug_print(SOCKETS_DEBUG, addr);
+        LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F" len=%d\n", port, off));
+      } else {
+#if SOCKETS_DEBUG
+        if (netconn_type(sock->conn) == NETCONN_TCP) {
+          addr = &fromaddr;
+          netconn_getaddr(sock->conn, addr, &port, 0);
+        } else {
+          addr = netbuf_fromaddr((struct netbuf *)buf);
+          port = netbuf_fromport((struct netbuf *)buf);
+        }
+
+        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom(%d): addr=", s));
+        ip_addr_debug_print(SOCKETS_DEBUG, addr);
+        LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F" len=%d\n", port, off));
+#endif /*  SOCKETS_DEBUG */
+      }
+    }
+
+    /* If we don't peek the incoming message... */
+    if ((flags & MSG_PEEK) == 0) {
+      /* If this is a TCP socket, check if there is data left in the
+         buffer. If so, it should be saved in the sock structure for next
+         time around. */
+      if ((netconn_type(sock->conn) == NETCONN_TCP) && (buflen - copylen > 0)) {
+        sock->lastdata = buf;
+        sock->lastoffset += copylen;
+        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom: lastdata now netbuf=%p\n", buf));
+      } else {
+        sock->lastdata = NULL;
+        sock->lastoffset = 0;
+        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom: deleting netbuf=%p\n", buf));
+        if (netconn_type(sock->conn) == NETCONN_TCP) {
+          pbuf_free((struct pbuf *)buf);
+        } else {
+          netbuf_delete((struct netbuf *)buf);
+        }
+      }
+    }
+  } while (!done);
+
+  if (off > 0) {
+    /* update receive window */
+    netconn_recved(sock->conn, (u32_t)off);
+  }
+  sock_set_errno(sock, 0);
+  return off;
+}
+
+int
+lwip_read(int s, void *mem, size_t len)
+{
+  return lwip_recvfrom(s, mem, len, 0, NULL, NULL);
+}
+
+int
+lwip_recv(int s, void *mem, size_t len, int flags)
+{
+  return lwip_recvfrom(s, mem, len, flags, NULL, NULL);
+}
+
+int
+lwip_send(int s, const void *data, size_t size, int flags)
+{
+  struct lwip_sock *sock;
+  err_t err;
+  u8_t write_flags;
+
+  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_send(%d, data=%p, size=%"SZT_F", flags=0x%x)\n",
+                              s, data, size, flags));
+
+  sock = get_socket(s);
+  if (!sock) {
+    return -1;
+  }
+
+  if (sock->conn->type != NETCONN_TCP) {
+#if (LWIP_UDP || LWIP_RAW)
+    return lwip_sendto(s, data, size, flags, NULL, 0);
+#else /* (LWIP_UDP || LWIP_RAW) */
+    sock_set_errno(sock, err_to_errno(ERR_ARG));
+    return -1;
+#endif /* (LWIP_UDP || LWIP_RAW) */
+  }
+
+  if ((flags & MSG_DONTWAIT) || netconn_is_nonblocking(sock->conn)) {
+    if ((size > TCP_SND_BUF) || ((size / TCP_MSS) > TCP_SND_QUEUELEN)) {
+      /* too much data to ever send nonblocking! */
+      sock_set_errno(sock, EMSGSIZE);
+      return -1;
+    }
+  }
+
+  write_flags = NETCONN_COPY |
+    ((flags & MSG_MORE)     ? NETCONN_MORE      : 0) |
+    ((flags & MSG_DONTWAIT) ? NETCONN_DONTBLOCK : 0);
+  err = netconn_write(sock->conn, data, size, write_flags);
+
+  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_send(%d) err=%d size=%"SZT_F"\n", s, err, size));
+  sock_set_errno(sock, err_to_errno(err));
+  return (err == ERR_OK ? (int)size : -1);
+}
+
+int
+lwip_sendto(int s, const void *data, size_t size, int flags,
+       const struct sockaddr *to, socklen_t tolen)
+{
+  struct lwip_sock *sock;
+  err_t err;
+  u16_t short_size;
+  const struct sockaddr_in *to_in;
+  u16_t remote_port;
+#if !LWIP_TCPIP_CORE_LOCKING
+  struct netbuf buf;
+#endif
+
+  sock = get_socket(s);
+  if (!sock) {
+    return -1;
+  }
+
+  if (sock->conn->type == NETCONN_TCP) {
+#if LWIP_TCP
+    return lwip_send(s, data, size, flags);
+#else /* LWIP_TCP */
+    LWIP_UNUSED_ARG(flags);
+    sock_set_errno(sock, err_to_errno(ERR_ARG));
+    return -1;
+#endif /* LWIP_TCP */
+  }
+
+  /* @todo: split into multiple sendto's? */
+  LWIP_ASSERT("lwip_sendto: size must fit in u16_t", size <= 0xffff);
+  short_size = (u16_t)size;
+  LWIP_ERROR("lwip_sendto: invalid address", (((to == NULL) && (tolen == 0)) ||
+             ((tolen == sizeof(struct sockaddr_in)) &&
+             ((to->sa_family) == AF_INET) && ((((mem_ptr_t)to) % 4) == 0))),
+             sock_set_errno(sock, err_to_errno(ERR_ARG)); return -1;);
+  to_in = (const struct sockaddr_in *)(void*)to;
+
+#if LWIP_TCPIP_CORE_LOCKING
+  /* Should only be consider like a sample or a simple way to experiment this option (no check of "to" field...) */
+  {
+    struct pbuf* p;
+    ip_addr_t *remote_addr;
+
+#if LWIP_NETIF_TX_SINGLE_PBUF
+    p = pbuf_alloc(PBUF_TRANSPORT, short_size, PBUF_RAM);
+    if (p != NULL) {
+#if LWIP_CHECKSUM_ON_COPY
+      u16_t chksum = 0;
+      if (sock->conn->type != NETCONN_RAW) {
+        chksum = LWIP_CHKSUM_COPY(p->payload, data, short_size);
+      } else
+#endif /* LWIP_CHECKSUM_ON_COPY */
+      MEMCPY(p->payload, data, size);
+#else /* LWIP_NETIF_TX_SINGLE_PBUF */
+    p = pbuf_alloc(PBUF_TRANSPORT, short_size, PBUF_REF);
+    if (p != NULL) {
+      p->payload = (void*)data;
+#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
+
+      if (to_in != NULL) {
+        inet_addr_to_ipaddr_p(remote_addr, &to_in->sin_addr);
+        remote_port = ntohs(to_in->sin_port);
+      } else {
+        remote_addr = &sock->conn->pcb.raw->remote_ip;
+        if (sock->conn->type == NETCONN_RAW) {
+          remote_port = 0;
+        } else {
+          remote_port = sock->conn->pcb.udp->remote_port;
+        }
+      }
+
+      LOCK_TCPIP_CORE();
+      if (sock->conn->type == NETCONN_RAW) {
+        err = sock->conn->last_err = raw_sendto(sock->conn->pcb.raw, p, remote_addr);
+      } else {
+#if LWIP_UDP
+#if LWIP_CHECKSUM_ON_COPY && LWIP_NETIF_TX_SINGLE_PBUF
+        err = sock->conn->last_err = udp_sendto_chksum(sock->conn->pcb.udp, p,
+          remote_addr, remote_port, 1, chksum);
+#else /* LWIP_CHECKSUM_ON_COPY && LWIP_NETIF_TX_SINGLE_PBUF */
+        err = sock->conn->last_err = udp_sendto(sock->conn->pcb.udp, p,
+          remote_addr, remote_port);
+#endif /* LWIP_CHECKSUM_ON_COPY && LWIP_NETIF_TX_SINGLE_PBUF */
+#else /* LWIP_UDP */
+        err = ERR_ARG;
+#endif /* LWIP_UDP */
+      }
+      UNLOCK_TCPIP_CORE();
+      
+      pbuf_free(p);
+    } else {
+      err = ERR_MEM;
+    }
+  }
+#else /* LWIP_TCPIP_CORE_LOCKING */
+  /* initialize a buffer */
+  buf.p = buf.ptr = NULL;
+#if LWIP_CHECKSUM_ON_COPY
+  buf.flags = 0;
+#endif /* LWIP_CHECKSUM_ON_COPY */
+  if (to) {
+    inet_addr_to_ipaddr(&buf.addr, &to_in->sin_addr);
+    remote_port           = ntohs(to_in->sin_port);
+    netbuf_fromport(&buf) = remote_port;
+  } else {
+    remote_port           = 0;
+    ip_addr_set_any(&buf.addr);
+    netbuf_fromport(&buf) = 0;
+  }
+
+  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_sendto(%d, data=%p, short_size=%"U16_F", flags=0x%x to=",
+              s, data, short_size, flags));
+  ip_addr_debug_print(SOCKETS_DEBUG, &buf.addr);
+  LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F"\n", remote_port));
+
+  /* make the buffer point to the data that should be sent */
+#if LWIP_NETIF_TX_SINGLE_PBUF
+  /* Allocate a new netbuf and copy the data into it. */
+  if (netbuf_alloc(&buf, short_size) == NULL) {
+    err = ERR_MEM;
+  } else {
+#if LWIP_CHECKSUM_ON_COPY
+    if (sock->conn->type != NETCONN_RAW) {
+      u16_t chksum = LWIP_CHKSUM_COPY(buf.p->payload, data, short_size);
+      netbuf_set_chksum(&buf, chksum);
+      err = ERR_OK;
+    } else
+#endif /* LWIP_CHECKSUM_ON_COPY */
+    {
+      err = netbuf_take(&buf, data, short_size);
+    }
+  }
+#else /* LWIP_NETIF_TX_SINGLE_PBUF */
+  err = netbuf_ref(&buf, data, short_size);
+#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
+  if (err == ERR_OK) {
+    /* send the data */
+    err = netconn_send(sock->conn, &buf);
+  }
+
+  /* deallocated the buffer */
+  netbuf_free(&buf);
+#endif /* LWIP_TCPIP_CORE_LOCKING */
+  sock_set_errno(sock, err_to_errno(err));
+  return (err == ERR_OK ? short_size : -1);
+}
+
+int
+lwip_socket(int domain, int type, int protocol)
+{
+  struct netconn *conn;
+  int i;
+
+  LWIP_UNUSED_ARG(domain);
+
+  /* create a netconn */
+  switch (type) {
+  case SOCK_RAW:
+    conn = netconn_new_with_proto_and_callback(NETCONN_RAW, (u8_t)protocol, event_callback);
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_socket(%s, SOCK_RAW, %d) = ",
+                                 domain == PF_INET ? "PF_INET" : "UNKNOWN", protocol));
+    break;
+  case SOCK_DGRAM:
+    conn = netconn_new_with_callback( (protocol == IPPROTO_UDPLITE) ?
+                 NETCONN_UDPLITE : NETCONN_UDP, event_callback);
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_socket(%s, SOCK_DGRAM, %d) = ",
+                                 domain == PF_INET ? "PF_INET" : "UNKNOWN", protocol));
+    break;
+  case SOCK_STREAM:
+    conn = netconn_new_with_callback(NETCONN_TCP, event_callback);
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_socket(%s, SOCK_STREAM, %d) = ",
+                                 domain == PF_INET ? "PF_INET" : "UNKNOWN", protocol));
+    if (conn != NULL) {
+      /* Prevent automatic window updates, we do this on our own! */
+      netconn_set_noautorecved(conn, 1);
+    }
+    break;
+  default:
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_socket(%d, %d/UNKNOWN, %d) = -1\n",
+                                 domain, type, protocol));
+    set_errno(EINVAL);
+    return -1;
+  }
+
+  if (!conn) {
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("-1 / ENOBUFS (could not create netconn)\n"));
+    set_errno(ENOBUFS);
+    return -1;
+  }
+
+  i = alloc_socket(conn, 0);
+
+  if (i == -1) {
+    netconn_delete(conn);
+    set_errno(ENFILE);
+    return -1;
+  }
+  conn->socket = i;
+  LWIP_DEBUGF(SOCKETS_DEBUG, ("%d\n", i));
+  set_errno(0);
+  return i;
+}
+
+int
+lwip_write(int s, const void *data, size_t size)
+{
+  return lwip_send(s, data, size, 0);
+}
+
+/**
+ * Go through the readset and writeset lists and see which socket of the sockets
+ * set in the sets has events. On return, readset, writeset and exceptset have
+ * the sockets enabled that had events.
+ *
+ * exceptset is not used for now!!!
+ *
+ * @param maxfdp1 the highest socket index in the sets
+ * @param readset_in:    set of sockets to check for read events
+ * @param writeset_in:   set of sockets to check for write events
+ * @param exceptset_in:  set of sockets to check for error events
+ * @param readset_out:   set of sockets that had read events
+ * @param writeset_out:  set of sockets that had write events
+ * @param exceptset_out: set os sockets that had error events
+ * @return number of sockets that had events (read/write/exception) (>= 0)
+ */
+static int
+lwip_selscan(int maxfdp1, fd_set *readset_in, fd_set *writeset_in, fd_set *exceptset_in,
+             fd_set *readset_out, fd_set *writeset_out, fd_set *exceptset_out)
+{
+  int i, nready = 0;
+  fd_set lreadset, lwriteset, lexceptset;
+  struct lwip_sock *sock;
+  SYS_ARCH_DECL_PROTECT(lev);
+
+  FD_ZERO(&lreadset);
+  FD_ZERO(&lwriteset);
+  FD_ZERO(&lexceptset);
+
+  /* Go through each socket in each list to count number of sockets which
+     currently match */
+  for(i = 0; i < maxfdp1; i++) {
+    void* lastdata = NULL;
+    s16_t rcvevent = 0;
+    u16_t sendevent = 0;
+    u16_t errevent = 0;
+    /* First get the socket's status (protected)... */
+    SYS_ARCH_PROTECT(lev);
+    sock = tryget_socket(i);
+    if (sock != NULL) {
+      lastdata = sock->lastdata;
+      rcvevent = sock->rcvevent;
+      sendevent = sock->sendevent;
+      errevent = sock->errevent;
+    }
+    SYS_ARCH_UNPROTECT(lev);
+    /* ... then examine it: */
+    /* See if netconn of this socket is ready for read */
+    if (readset_in && FD_ISSET(i, readset_in) && ((lastdata != NULL) || (rcvevent > 0))) {
+      FD_SET(i, &lreadset);
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_selscan: fd=%d ready for reading\n", i));
+      nready++;
+    }
+    /* See if netconn of this socket is ready for write */
+    if (writeset_in && FD_ISSET(i, writeset_in) && (sendevent != 0)) {
+      FD_SET(i, &lwriteset);
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_selscan: fd=%d ready for writing\n", i));
+      nready++;
+    }
+    /* See if netconn of this socket had an error */
+    if (exceptset_in && FD_ISSET(i, exceptset_in) && (errevent != 0)) {
+      FD_SET(i, &lexceptset);
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_selscan: fd=%d ready for exception\n", i));
+      nready++;
+    }
+  }
+  /* copy local sets to the ones provided as arguments */
+  *readset_out = lreadset;
+  *writeset_out = lwriteset;
+  *exceptset_out = lexceptset;
+
+  LWIP_ASSERT("nready >= 0", nready >= 0);
+  return nready;
+}
+
+/**
+ * Processing exceptset is not yet implemented.
+ */
+int
+lwip_select(int maxfdp1, fd_set *readset, fd_set *writeset, fd_set *exceptset,
+            struct timeval *timeout)
+{
+  u32_t waitres = 0;
+  int nready;
+  fd_set lreadset, lwriteset, lexceptset;
+  u32_t msectimeout;
+  struct lwip_select_cb select_cb;
+  err_t err;
+  int i;
+  SYS_ARCH_DECL_PROTECT(lev);
+
+  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_select(%d, %p, %p, %p, tvsec=%"S32_F" tvusec=%"S32_F")\n",
+                  maxfdp1, (void *)readset, (void *) writeset, (void *) exceptset,
+                  timeout ? (s32_t)timeout->tv_sec : (s32_t)-1,
+                  timeout ? (s32_t)timeout->tv_usec : (s32_t)-1));
+
+  /* Go through each socket in each list to count number of sockets which
+     currently match */
+  nready = lwip_selscan(maxfdp1, readset, writeset, exceptset, &lreadset, &lwriteset, &lexceptset);
+
+  /* If we don't have any current events, then suspend if we are supposed to */
+  if (!nready) {
+    if (timeout && timeout->tv_sec == 0 && timeout->tv_usec == 0) {
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_select: no timeout, returning 0\n"));
+      /* This is OK as the local fdsets are empty and nready is zero,
+         or we would have returned earlier. */
+      goto return_copy_fdsets;
+    }
+
+    /* None ready: add our semaphore to list:
+       We don't actually need any dynamic memory. Our entry on the
+       list is only valid while we are in this function, so it's ok
+       to use local variables. */
+
+    select_cb.next = NULL;
+    select_cb.prev = NULL;
+    select_cb.readset = readset;
+    select_cb.writeset = writeset;
+    select_cb.exceptset = exceptset;
+    select_cb.sem_signalled = 0;
+    err = sys_sem_new(&select_cb.sem, 0);
+    if (err != ERR_OK) {
+      /* failed to create semaphore */
+      set_errno(ENOMEM);
+      return -1;
+    }
+
+    /* Protect the select_cb_list */
+    SYS_ARCH_PROTECT(lev);
+
+    /* Put this select_cb on top of list */
+    select_cb.next = select_cb_list;
+    if (select_cb_list != NULL) {
+      select_cb_list->prev = &select_cb;
+    }
+    select_cb_list = &select_cb;
+    /* Increasing this counter tells even_callback that the list has changed. */
+    select_cb_ctr++;
+
+    /* Now we can safely unprotect */
+    SYS_ARCH_UNPROTECT(lev);
+
+    /* Increase select_waiting for each socket we are interested in */
+    for(i = 0; i < maxfdp1; i++) {
+      if ((readset && FD_ISSET(i, readset)) ||
+          (writeset && FD_ISSET(i, writeset)) ||
+          (exceptset && FD_ISSET(i, exceptset))) {
+        struct lwip_sock *sock = tryget_socket(i);
+        LWIP_ASSERT("sock != NULL", sock != NULL);
+        SYS_ARCH_PROTECT(lev);
+        sock->select_waiting++;
+        LWIP_ASSERT("sock->select_waiting > 0", sock->select_waiting > 0);
+        SYS_ARCH_UNPROTECT(lev);
+      }
+    }
+
+    /* Call lwip_selscan again: there could have been events between
+       the last scan (whithout us on the list) and putting us on the list! */
+    nready = lwip_selscan(maxfdp1, readset, writeset, exceptset, &lreadset, &lwriteset, &lexceptset);
+    if (!nready) {
+      /* Still none ready, just wait to be woken */
+      if (timeout == 0) {
+        /* Wait forever */
+        msectimeout = 0;
+      } else {
+        msectimeout =  ((timeout->tv_sec * 1000) + ((timeout->tv_usec + 500)/1000));
+        if (msectimeout == 0) {
+          /* Wait 1ms at least (0 means wait forever) */
+          msectimeout = 1;
+        }
+      }
+
+      waitres = sys_arch_sem_wait(&select_cb.sem, msectimeout);
+    }
+    /* Increase select_waiting for each socket we are interested in */
+    for(i = 0; i < maxfdp1; i++) {
+      if ((readset && FD_ISSET(i, readset)) ||
+          (writeset && FD_ISSET(i, writeset)) ||
+          (exceptset && FD_ISSET(i, exceptset))) {
+        struct lwip_sock *sock = tryget_socket(i);
+        LWIP_ASSERT("sock != NULL", sock != NULL);
+        SYS_ARCH_PROTECT(lev);
+        sock->select_waiting--;
+        LWIP_ASSERT("sock->select_waiting >= 0", sock->select_waiting >= 0);
+        SYS_ARCH_UNPROTECT(lev);
+      }
+    }
+    /* Take us off the list */
+    SYS_ARCH_PROTECT(lev);
+    if (select_cb.next != NULL) {
+      select_cb.next->prev = select_cb.prev;
+    }
+    if (select_cb_list == &select_cb) {
+      LWIP_ASSERT("select_cb.prev == NULL", select_cb.prev == NULL);
+      select_cb_list = select_cb.next;
+    } else {
+      LWIP_ASSERT("select_cb.prev != NULL", select_cb.prev != NULL);
+      select_cb.prev->next = select_cb.next;
+    }
+    /* Increasing this counter tells even_callback that the list has changed. */
+    select_cb_ctr++;
+    SYS_ARCH_UNPROTECT(lev);
+
+    sys_sem_free(&select_cb.sem);
+    if (waitres == SYS_ARCH_TIMEOUT)  {
+      /* Timeout */
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_select: timeout expired\n"));
+      /* This is OK as the local fdsets are empty and nready is zero,
+         or we would have returned earlier. */
+      goto return_copy_fdsets;
+    }
+
+    /* See what's set */
+    nready = lwip_selscan(maxfdp1, readset, writeset, exceptset, &lreadset, &lwriteset, &lexceptset);
+  }
+
+  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_select: nready=%d\n", nready));
+return_copy_fdsets:
+  set_errno(0);
+  if (readset) {
+    *readset = lreadset;
+  }
+  if (writeset) {
+    *writeset = lwriteset;
+  }
+  if (exceptset) {
+    *exceptset = lexceptset;
+  }
+
+
+  return nready;
+}
+
+/**
+ * Callback registered in the netconn layer for each socket-netconn.
+ * Processes recvevent (data available) and wakes up tasks waiting for select.
+ */
+static void
+event_callback(struct netconn *conn, enum netconn_evt evt, u16_t len)
+{
+  int s;
+  struct lwip_sock *sock;
+  struct lwip_select_cb *scb;
+  int last_select_cb_ctr;
+  SYS_ARCH_DECL_PROTECT(lev);
+
+  LWIP_UNUSED_ARG(len);
+
+  /* Get socket */
+  if (conn) {
+    s = conn->socket;
+    if (s < 0) {
+      /* Data comes in right away after an accept, even though
+       * the server task might not have created a new socket yet.
+       * Just count down (or up) if that's the case and we
+       * will use the data later. Note that only receive events
+       * can happen before the new socket is set up. */
+      SYS_ARCH_PROTECT(lev);
+      if (conn->socket < 0) {
+        if (evt == NETCONN_EVT_RCVPLUS) {
+          conn->socket--;
+        }
+        SYS_ARCH_UNPROTECT(lev);
+        return;
+      }
+      s = conn->socket;
+      SYS_ARCH_UNPROTECT(lev);
+    }
+
+    sock = get_socket(s);
+    if (!sock) {
+      return;
+    }
+  } else {
+    return;
+  }
+
+  SYS_ARCH_PROTECT(lev);
+  /* Set event as required */
+  switch (evt) {
+    case NETCONN_EVT_RCVPLUS:
+      sock->rcvevent++;
+      break;
+    case NETCONN_EVT_RCVMINUS:
+      sock->rcvevent--;
+      break;
+    case NETCONN_EVT_SENDPLUS:
+      sock->sendevent = 1;
+      break;
+    case NETCONN_EVT_SENDMINUS:
+      sock->sendevent = 0;
+      break;
+    case NETCONN_EVT_ERROR:
+      sock->errevent = 1;
+      break;
+    default:
+      LWIP_ASSERT("unknown event", 0);
+      break;
+  }
+
+  if (sock->select_waiting == 0) {
+    /* noone is waiting for this socket, no need to check select_cb_list */
+    SYS_ARCH_UNPROTECT(lev);
+    return;
+  }
+
+  /* Now decide if anyone is waiting for this socket */
+  /* NOTE: This code goes through the select_cb_list list multiple times
+     ONLY IF a select was actually waiting. We go through the list the number
+     of waiting select calls + 1. This list is expected to be small. */
+
+  /* At this point, SYS_ARCH is still protected! */
+again:
+  for (scb = select_cb_list; scb != NULL; scb = scb->next) {
+    if (scb->sem_signalled == 0) {
+      /* semaphore not signalled yet */
+      int do_signal = 0;
+      /* Test this select call for our socket */
+      if (sock->rcvevent > 0) {
+        if (scb->readset && FD_ISSET(s, scb->readset)) {
+          do_signal = 1;
+        }
+      }
+      if (sock->sendevent != 0) {
+        if (!do_signal && scb->writeset && FD_ISSET(s, scb->writeset)) {
+          do_signal = 1;
+        }
+      }
+      if (sock->errevent != 0) {
+        if (!do_signal && scb->exceptset && FD_ISSET(s, scb->exceptset)) {
+          do_signal = 1;
+        }
+      }
+      if (do_signal) {
+        scb->sem_signalled = 1;
+        /* Don't call SYS_ARCH_UNPROTECT() before signaling the semaphore, as this might
+           lead to the select thread taking itself off the list, invalidagin the semaphore. */
+        sys_sem_signal(&scb->sem);
+      }
+    }
+    /* unlock interrupts with each step */
+    last_select_cb_ctr = select_cb_ctr;
+    SYS_ARCH_UNPROTECT(lev);
+    /* this makes sure interrupt protection time is short */
+    SYS_ARCH_PROTECT(lev);
+    if (last_select_cb_ctr != select_cb_ctr) {
+      /* someone has changed select_cb_list, restart at the beginning */
+      goto again;
+    }
+  }
+  SYS_ARCH_UNPROTECT(lev);
+}
+
+/**
+ * Unimplemented: Close one end of a full-duplex connection.
+ * Currently, the full connection is closed.
+ */
+int
+lwip_shutdown(int s, int how)
+{
+  struct lwip_sock *sock;
+  err_t err;
+  u8_t shut_rx = 0, shut_tx = 0;
+
+  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_shutdown(%d, how=%d)\n", s, how));
+
+  sock = get_socket(s);
+  if (!sock) {
+    return -1;
+  }
+
+  if (sock->conn != NULL) {
+    if (netconn_type(sock->conn) != NETCONN_TCP) {
+      sock_set_errno(sock, EOPNOTSUPP);
+      return EOPNOTSUPP;
+    }
+  } else {
+    sock_set_errno(sock, ENOTCONN);
+    return ENOTCONN;
+  }
+
+  if (how == SHUT_RD) {
+    shut_rx = 1;
+  } else if (how == SHUT_WR) {
+    shut_tx = 1;
+  } else if(how == SHUT_RDWR) {
+    shut_rx = 1;
+    shut_tx = 1;
+  } else {
+    sock_set_errno(sock, EINVAL);
+    return EINVAL;
+  }
+  err = netconn_shutdown(sock->conn, shut_rx, shut_tx);
+
+  sock_set_errno(sock, err_to_errno(err));
+  return (err == ERR_OK ? 0 : -1);
+}
+
+static int
+lwip_getaddrname(int s, struct sockaddr *name, socklen_t *namelen, u8_t local)
+{
+  struct lwip_sock *sock;
+  struct sockaddr_in sin;
+  ip_addr_t naddr;
+
+  sock = get_socket(s);
+  if (!sock) {
+    return -1;
+  }
+
+  memset(&sin, 0, sizeof(sin));
+  sin.sin_len = sizeof(sin);
+  sin.sin_family = AF_INET;
+
+  /* get the IP address and port */
+  netconn_getaddr(sock->conn, &naddr, &sin.sin_port, local);
+
+  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getaddrname(%d, addr=", s));
+  ip_addr_debug_print(SOCKETS_DEBUG, &naddr);
+  LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F")\n", sin.sin_port));
+
+  sin.sin_port = htons(sin.sin_port);
+  inet_addr_from_ipaddr(&sin.sin_addr, &naddr);
+
+  if (*namelen > sizeof(sin)) {
+    *namelen = sizeof(sin);
+  }
+
+  MEMCPY(name, &sin, *namelen);
+  sock_set_errno(sock, 0);
+  return 0;
+}
+
+int
+lwip_getpeername(int s, struct sockaddr *name, socklen_t *namelen)
+{
+  return lwip_getaddrname(s, name, namelen, 0);
+}
+
+int
+lwip_getsockname(int s, struct sockaddr *name, socklen_t *namelen)
+{
+  return lwip_getaddrname(s, name, namelen, 1);
+}
+
+int
+lwip_getsockopt(int s, int level, int optname, void *optval, socklen_t *optlen)
+{
+  err_t err = ERR_OK;
+  struct lwip_sock *sock = get_socket(s);
+  struct lwip_setgetsockopt_data data;
+
+  if (!sock) {
+    return -1;
+  }
+
+  if ((NULL == optval) || (NULL == optlen)) {
+    sock_set_errno(sock, EFAULT);
+    return -1;
+  }
+
+  /* Do length and type checks for the various options first, to keep it readable. */
+  switch (level) {
+   
+/* Level: SOL_SOCKET */
+  case SOL_SOCKET:
+    switch (optname) {
+       
+    case SO_ACCEPTCONN:
+    case SO_BROADCAST:
+    /* UNIMPL case SO_DEBUG: */
+    /* UNIMPL case SO_DONTROUTE: */
+    case SO_ERROR:
+    case SO_KEEPALIVE:
+    /* UNIMPL case SO_CONTIMEO: */
+    /* UNIMPL case SO_SNDTIMEO: */
+#if LWIP_SO_RCVTIMEO
+    case SO_RCVTIMEO:
+#endif /* LWIP_SO_RCVTIMEO */
+#if LWIP_SO_RCVBUF
+    case SO_RCVBUF:
+#endif /* LWIP_SO_RCVBUF */
+    /* UNIMPL case SO_OOBINLINE: */
+    /* UNIMPL case SO_SNDBUF: */
+    /* UNIMPL case SO_RCVLOWAT: */
+    /* UNIMPL case SO_SNDLOWAT: */
+#if SO_REUSE
+    case SO_REUSEADDR:
+    case SO_REUSEPORT:
+#endif /* SO_REUSE */
+    case SO_TYPE:
+    /* UNIMPL case SO_USELOOPBACK: */
+      if (*optlen < sizeof(int)) {
+        err = EINVAL;
+      }
+      break;
+
+    case SO_NO_CHECK:
+      if (*optlen < sizeof(int)) {
+        err = EINVAL;
+      }
+#if LWIP_UDP
+      if ((sock->conn->type != NETCONN_UDP) ||
+          ((udp_flags(sock->conn->pcb.udp) & UDP_FLAGS_UDPLITE) != 0)) {
+        /* this flag is only available for UDP, not for UDP lite */
+        err = EAFNOSUPPORT;
+      }
+#endif /* LWIP_UDP */
+      break;
+
+    default:
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, SOL_SOCKET, UNIMPL: optname=0x%x, ..)\n",
+                                  s, optname));
+      err = ENOPROTOOPT;
+    }  /* switch (optname) */
+    break;
+                     
+/* Level: IPPROTO_IP */
+  case IPPROTO_IP:
+    switch (optname) {
+    /* UNIMPL case IP_HDRINCL: */
+    /* UNIMPL case IP_RCVDSTADDR: */
+    /* UNIMPL case IP_RCVIF: */
+    case IP_TTL:
+    case IP_TOS:
+      if (*optlen < sizeof(int)) {
+        err = EINVAL;
+      }
+      break;
+#if LWIP_IGMP
+    case IP_MULTICAST_TTL:
+      if (*optlen < sizeof(u8_t)) {
+        err = EINVAL;
+      }
+      break;
+    case IP_MULTICAST_IF:
+      if (*optlen < sizeof(struct in_addr)) {
+        err = EINVAL;
+      }
+      break;
+    case IP_MULTICAST_LOOP:
+      if (*optlen < sizeof(u8_t)) {
+        err = EINVAL;
+      }
+      if (NETCONNTYPE_GROUP(sock->conn->type) != NETCONN_UDP) {
+        err = EAFNOSUPPORT;
+      }
+      break;
+#endif /* LWIP_IGMP */
+
+    default:
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, UNIMPL: optname=0x%x, ..)\n",
+                                  s, optname));
+      err = ENOPROTOOPT;
+    }  /* switch (optname) */
+    break;
+         
+#if LWIP_TCP
+/* Level: IPPROTO_TCP */
+  case IPPROTO_TCP:
+    if (*optlen < sizeof(int)) {
+      err = EINVAL;
+      break;
+    }
+    
+    /* If this is no TCP socket, ignore any options. */
+    if (sock->conn->type != NETCONN_TCP)
+      return 0;
+
+    switch (optname) {
+    case TCP_NODELAY:
+    case TCP_KEEPALIVE:
+#if LWIP_TCP_KEEPALIVE
+    case TCP_KEEPIDLE:
+    case TCP_KEEPINTVL:
+    case TCP_KEEPCNT:
+#endif /* LWIP_TCP_KEEPALIVE */
+      break;
+       
+    default:
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_TCP, UNIMPL: optname=0x%x, ..)\n",
+                                  s, optname));
+      err = ENOPROTOOPT;
+    }  /* switch (optname) */
+    break;
+#endif /* LWIP_TCP */
+#if LWIP_UDP && LWIP_UDPLITE
+/* Level: IPPROTO_UDPLITE */
+  case IPPROTO_UDPLITE:
+    if (*optlen < sizeof(int)) {
+      err = EINVAL;
+      break;
+    }
+    
+    /* If this is no UDP lite socket, ignore any options. */
+    if (sock->conn->type != NETCONN_UDPLITE) {
+      return 0;
+    }
+
+    switch (optname) {
+    case UDPLITE_SEND_CSCOV:
+    case UDPLITE_RECV_CSCOV:
+      break;
+       
+    default:
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_UDPLITE, UNIMPL: optname=0x%x, ..)\n",
+                                  s, optname));
+      err = ENOPROTOOPT;
+    }  /* switch (optname) */
+    break;
+#endif /* LWIP_UDP && LWIP_UDPLITE*/
+/* UNDEFINED LEVEL */
+  default:
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, level=0x%x, UNIMPL: optname=0x%x, ..)\n",
+                                  s, level, optname));
+      err = ENOPROTOOPT;
+  }  /* switch */
+
+   
+  if (err != ERR_OK) {
+    sock_set_errno(sock, err);
+    return -1;
+  }
+
+  /* Now do the actual option processing */
+  data.sock = sock;
+#ifdef LWIP_DEBUG
+  data.s = s;
+#endif /* LWIP_DEBUG */
+  data.level = level;
+  data.optname = optname;
+  data.optval = optval;
+  data.optlen = optlen;
+  data.err = err;
+  tcpip_callback(lwip_getsockopt_internal, &data);
+  sys_arch_sem_wait(&sock->conn->op_completed, 0);
+  /* maybe lwip_getsockopt_internal has changed err */
+  err = data.err;
+
+  sock_set_errno(sock, err);
+  return err ? -1 : 0;
+}
+
+static void
+lwip_getsockopt_internal(void *arg)
+{
+  struct lwip_sock *sock;
+#ifdef LWIP_DEBUG
+  int s;
+#endif /* LWIP_DEBUG */
+  int level, optname;
+  void *optval;
+  struct lwip_setgetsockopt_data *data;
+
+  LWIP_ASSERT("arg != NULL", arg != NULL);
+
+  data = (struct lwip_setgetsockopt_data*)arg;
+  sock = data->sock;
+#ifdef LWIP_DEBUG
+  s = data->s;
+#endif /* LWIP_DEBUG */
+  level = data->level;
+  optname = data->optname;
+  optval = data->optval;
+
+  switch (level) {
+
+/* Level: SOL_SOCKET */
+  case SOL_SOCKET:
+    switch (optname) {
+
+    /* The option flags */
+    case SO_ACCEPTCONN:
+    case SO_BROADCAST:
+    /* UNIMPL case SO_DEBUG: */
+    /* UNIMPL case SO_DONTROUTE: */
+    case SO_KEEPALIVE:
+    /* UNIMPL case SO_OOBINCLUDE: */
+#if SO_REUSE
+    case SO_REUSEADDR:
+    case SO_REUSEPORT:
+#endif /* SO_REUSE */
+    /*case SO_USELOOPBACK: UNIMPL */
+      *(int*)optval = sock->conn->pcb.ip->so_options & optname;
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, SOL_SOCKET, optname=0x%x, ..) = %s\n",
+                                  s, optname, (*(int*)optval?"on":"off")));
+      break;
+
+    case SO_TYPE:
+      switch (NETCONNTYPE_GROUP(sock->conn->type)) {
+      case NETCONN_RAW:
+        *(int*)optval = SOCK_RAW;
+        break;
+      case NETCONN_TCP:
+        *(int*)optval = SOCK_STREAM;
+        break;
+      case NETCONN_UDP:
+        *(int*)optval = SOCK_DGRAM;
+        break;
+      default: /* unrecognized socket type */
+        *(int*)optval = sock->conn->type;
+        LWIP_DEBUGF(SOCKETS_DEBUG,
+                    ("lwip_getsockopt(%d, SOL_SOCKET, SO_TYPE): unrecognized socket type %d\n",
+                    s, *(int *)optval));
+      }  /* switch (sock->conn->type) */
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, SOL_SOCKET, SO_TYPE) = %d\n",
+                  s, *(int *)optval));
+      break;
+
+    case SO_ERROR:
+      /* only overwrite ERR_OK or tempoary errors */
+      if ((sock->err == 0) || (sock->err == EINPROGRESS)) {
+        sock_set_errno(sock, err_to_errno(sock->conn->last_err));
+      } 
+      *(int *)optval = sock->err;
+      sock->err = 0;
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, SOL_SOCKET, SO_ERROR) = %d\n",
+                  s, *(int *)optval));
+      break;
+
+#if LWIP_SO_RCVTIMEO
+    case SO_RCVTIMEO:
+      *(int *)optval = netconn_get_recvtimeout(sock->conn);
+      break;
+#endif /* LWIP_SO_RCVTIMEO */
+#if LWIP_SO_RCVBUF
+    case SO_RCVBUF:
+      *(int *)optval = netconn_get_recvbufsize(sock->conn);
+      break;
+#endif /* LWIP_SO_RCVBUF */
+#if LWIP_UDP
+    case SO_NO_CHECK:
+      *(int*)optval = (udp_flags(sock->conn->pcb.udp) & UDP_FLAGS_NOCHKSUM) ? 1 : 0;
+      break;
+#endif /* LWIP_UDP*/
+    default:
+      LWIP_ASSERT("unhandled optname", 0);
+      break;
+    }  /* switch (optname) */
+    break;
+
+/* Level: IPPROTO_IP */
+  case IPPROTO_IP:
+    switch (optname) {
+    case IP_TTL:
+      *(int*)optval = sock->conn->pcb.ip->ttl;
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, IP_TTL) = %d\n",
+                  s, *(int *)optval));
+      break;
+    case IP_TOS:
+      *(int*)optval = sock->conn->pcb.ip->tos;
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, IP_TOS) = %d\n",
+                  s, *(int *)optval));
+      break;
+#if LWIP_IGMP
+    case IP_MULTICAST_TTL:
+      *(u8_t*)optval = sock->conn->pcb.ip->ttl;
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, IP_MULTICAST_TTL) = %d\n",
+                  s, *(int *)optval));
+      break;
+    case IP_MULTICAST_IF:
+      inet_addr_from_ipaddr((struct in_addr*)optval, &sock->conn->pcb.udp->multicast_ip);
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, IP_MULTICAST_IF) = 0x%"X32_F"\n",
+                  s, *(u32_t *)optval));
+      break;
+    case IP_MULTICAST_LOOP:
+      if ((sock->conn->pcb.udp->flags & UDP_FLAGS_MULTICAST_LOOP) != 0) {
+        *(u8_t*)optval = 1;
+      } else {
+        *(u8_t*)optval = 0;
+      }
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, IP_MULTICAST_LOOP) = %d\n",
+                  s, *(int *)optval));
+      break;
+#endif /* LWIP_IGMP */
+    default:
+      LWIP_ASSERT("unhandled optname", 0);
+      break;
+    }  /* switch (optname) */
+    break;
+
+#if LWIP_TCP
+/* Level: IPPROTO_TCP */
+  case IPPROTO_TCP:
+    switch (optname) {
+    case TCP_NODELAY:
+      *(int*)optval = tcp_nagle_disabled(sock->conn->pcb.tcp);
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_TCP, TCP_NODELAY) = %s\n",
+                  s, (*(int*)optval)?"on":"off") );
+      break;
+    case TCP_KEEPALIVE:
+      *(int*)optval = (int)sock->conn->pcb.tcp->keep_idle;
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, TCP_KEEPALIVE) = %d\n",
+                  s, *(int *)optval));
+      break;
+
+#if LWIP_TCP_KEEPALIVE
+    case TCP_KEEPIDLE:
+      *(int*)optval = (int)(sock->conn->pcb.tcp->keep_idle/1000);
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, TCP_KEEPIDLE) = %d\n",
+                  s, *(int *)optval));
+      break;
+    case TCP_KEEPINTVL:
+      *(int*)optval = (int)(sock->conn->pcb.tcp->keep_intvl/1000);
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, TCP_KEEPINTVL) = %d\n",
+                  s, *(int *)optval));
+      break;
+    case TCP_KEEPCNT:
+      *(int*)optval = (int)sock->conn->pcb.tcp->keep_cnt;
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, TCP_KEEPCNT) = %d\n",
+                  s, *(int *)optval));
+      break;
+#endif /* LWIP_TCP_KEEPALIVE */
+    default:
+      LWIP_ASSERT("unhandled optname", 0);
+      break;
+    }  /* switch (optname) */
+    break;
+#endif /* LWIP_TCP */
+#if LWIP_UDP && LWIP_UDPLITE
+  /* Level: IPPROTO_UDPLITE */
+  case IPPROTO_UDPLITE:
+    switch (optname) {
+    case UDPLITE_SEND_CSCOV:
+      *(int*)optval = sock->conn->pcb.udp->chksum_len_tx;
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_UDPLITE, UDPLITE_SEND_CSCOV) = %d\n",
+                  s, (*(int*)optval)) );
+      break;
+    case UDPLITE_RECV_CSCOV:
+      *(int*)optval = sock->conn->pcb.udp->chksum_len_rx;
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_UDPLITE, UDPLITE_RECV_CSCOV) = %d\n",
+                  s, (*(int*)optval)) );
+      break;
+    default:
+      LWIP_ASSERT("unhandled optname", 0);
+      break;
+    }  /* switch (optname) */
+    break;
+#endif /* LWIP_UDP */
+  default:
+    LWIP_ASSERT("unhandled level", 0);
+    break;
+  } /* switch (level) */
+  sys_sem_signal(&sock->conn->op_completed);
+}
+
+int
+lwip_setsockopt(int s, int level, int optname, const void *optval, socklen_t optlen)
+{
+  struct lwip_sock *sock = get_socket(s);
+  err_t err = ERR_OK;
+  struct lwip_setgetsockopt_data data;
+
+  if (!sock) {
+    return -1;
+  }
+
+  if (NULL == optval) {
+    sock_set_errno(sock, EFAULT);
+    return -1;
+  }
+
+  /* Do length and type checks for the various options first, to keep it readable. */
+  switch (level) {
+
+/* Level: SOL_SOCKET */
+  case SOL_SOCKET:
+    switch (optname) {
+
+    case SO_BROADCAST:
+    /* UNIMPL case SO_DEBUG: */
+    /* UNIMPL case SO_DONTROUTE: */
+    case SO_KEEPALIVE:
+    /* UNIMPL case case SO_CONTIMEO: */
+    /* UNIMPL case case SO_SNDTIMEO: */
+#if LWIP_SO_RCVTIMEO
+    case SO_RCVTIMEO:
+#endif /* LWIP_SO_RCVTIMEO */
+#if LWIP_SO_RCVBUF
+    case SO_RCVBUF:
+#endif /* LWIP_SO_RCVBUF */
+    /* UNIMPL case SO_OOBINLINE: */
+    /* UNIMPL case SO_SNDBUF: */
+    /* UNIMPL case SO_RCVLOWAT: */
+    /* UNIMPL case SO_SNDLOWAT: */
+#if SO_REUSE
+    case SO_REUSEADDR:
+    case SO_REUSEPORT:
+#endif /* SO_REUSE */
+    /* UNIMPL case SO_USELOOPBACK: */
+      if (optlen < sizeof(int)) {
+        err = EINVAL;
+      }
+      break;
+    case SO_NO_CHECK:
+      if (optlen < sizeof(int)) {
+        err = EINVAL;
+      }
+#if LWIP_UDP
+      if ((sock->conn->type != NETCONN_UDP) ||
+          ((udp_flags(sock->conn->pcb.udp) & UDP_FLAGS_UDPLITE) != 0)) {
+        /* this flag is only available for UDP, not for UDP lite */
+        err = EAFNOSUPPORT;
+      }
+#endif /* LWIP_UDP */
+      break;
+    default:
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, SOL_SOCKET, UNIMPL: optname=0x%x, ..)\n",
+                  s, optname));
+      err = ENOPROTOOPT;
+    }  /* switch (optname) */
+    break;
+
+/* Level: IPPROTO_IP */
+  case IPPROTO_IP:
+    switch (optname) {
+    /* UNIMPL case IP_HDRINCL: */
+    /* UNIMPL case IP_RCVDSTADDR: */
+    /* UNIMPL case IP_RCVIF: */
+    case IP_TTL:
+    case IP_TOS:
+      if (optlen < sizeof(int)) {
+        err = EINVAL;
+      }
+      break;
+#if LWIP_IGMP
+    case IP_MULTICAST_TTL:
+      if (optlen < sizeof(u8_t)) {
+        err = EINVAL;
+      }
+      if (NETCONNTYPE_GROUP(sock->conn->type) != NETCONN_UDP) {
+        err = EAFNOSUPPORT;
+      }
+      break;
+    case IP_MULTICAST_IF:
+      if (optlen < sizeof(struct in_addr)) {
+        err = EINVAL;
+      }
+      if (NETCONNTYPE_GROUP(sock->conn->type) != NETCONN_UDP) {
+        err = EAFNOSUPPORT;
+      }
+      break;
+    case IP_MULTICAST_LOOP:
+      if (optlen < sizeof(u8_t)) {
+        err = EINVAL;
+      }
+      if (NETCONNTYPE_GROUP(sock->conn->type) != NETCONN_UDP) {
+        err = EAFNOSUPPORT;
+      }
+      break;
+    case IP_ADD_MEMBERSHIP:
+    case IP_DROP_MEMBERSHIP:
+      if (optlen < sizeof(struct ip_mreq)) {
+        err = EINVAL;
+      }
+      if (NETCONNTYPE_GROUP(sock->conn->type) != NETCONN_UDP) {
+        err = EAFNOSUPPORT;
+      }
+      break;
+#endif /* LWIP_IGMP */
+      default:
+        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_IP, UNIMPL: optname=0x%x, ..)\n",
+                    s, optname));
+        err = ENOPROTOOPT;
+    }  /* switch (optname) */
+    break;
+
+#if LWIP_TCP
+/* Level: IPPROTO_TCP */
+  case IPPROTO_TCP:
+    if (optlen < sizeof(int)) {
+      err = EINVAL;
+      break;
+    }
+
+    /* If this is no TCP socket, ignore any options. */
+    if (sock->conn->type != NETCONN_TCP)
+      return 0;
+
+    switch (optname) {
+    case TCP_NODELAY:
+    case TCP_KEEPALIVE:
+#if LWIP_TCP_KEEPALIVE
+    case TCP_KEEPIDLE:
+    case TCP_KEEPINTVL:
+    case TCP_KEEPCNT:
+#endif /* LWIP_TCP_KEEPALIVE */
+      break;
+
+    default:
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_TCP, UNIMPL: optname=0x%x, ..)\n",
+                  s, optname));
+      err = ENOPROTOOPT;
+    }  /* switch (optname) */
+    break;
+#endif /* LWIP_TCP */
+#if LWIP_UDP && LWIP_UDPLITE
+/* Level: IPPROTO_UDPLITE */
+  case IPPROTO_UDPLITE:
+    if (optlen < sizeof(int)) {
+      err = EINVAL;
+      break;
+    }
+
+    /* If this is no UDP lite socket, ignore any options. */
+    if (sock->conn->type != NETCONN_UDPLITE)
+      return 0;
+
+    switch (optname) {
+    case UDPLITE_SEND_CSCOV:
+    case UDPLITE_RECV_CSCOV:
+      break;
+
+    default:
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_UDPLITE, UNIMPL: optname=0x%x, ..)\n",
+                  s, optname));
+      err = ENOPROTOOPT;
+    }  /* switch (optname) */
+    break;
+#endif /* LWIP_UDP && LWIP_UDPLITE */
+/* UNDEFINED LEVEL */
+  default:
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, level=0x%x, UNIMPL: optname=0x%x, ..)\n",
+                s, level, optname));
+    err = ENOPROTOOPT;
+  }  /* switch (level) */
+
+
+  if (err != ERR_OK) {
+    sock_set_errno(sock, err);
+    return -1;
+  }
+
+
+  /* Now do the actual option processing */
+  data.sock = sock;
+#ifdef LWIP_DEBUG
+  data.s = s;
+#endif /* LWIP_DEBUG */
+  data.level = level;
+  data.optname = optname;
+  data.optval = (void*)optval;
+  data.optlen = &optlen;
+  data.err = err;
+  tcpip_callback(lwip_setsockopt_internal, &data);
+  sys_arch_sem_wait(&sock->conn->op_completed, 0);
+  /* maybe lwip_setsockopt_internal has changed err */
+  err = data.err;
+
+  sock_set_errno(sock, err);
+  return err ? -1 : 0;
+}
+
+static void
+lwip_setsockopt_internal(void *arg)
+{
+  struct lwip_sock *sock;
+#ifdef LWIP_DEBUG
+  int s;
+#endif /* LWIP_DEBUG */
+  int level, optname;
+  const void *optval;
+  struct lwip_setgetsockopt_data *data;
+
+  LWIP_ASSERT("arg != NULL", arg != NULL);
+
+  data = (struct lwip_setgetsockopt_data*)arg;
+  sock = data->sock;
+#ifdef LWIP_DEBUG
+  s = data->s;
+#endif /* LWIP_DEBUG */
+  level = data->level;
+  optname = data->optname;
+  optval = data->optval;
+
+  switch (level) {
+
+/* Level: SOL_SOCKET */
+  case SOL_SOCKET:
+    switch (optname) {
+
+    /* The option flags */
+    case SO_BROADCAST:
+    /* UNIMPL case SO_DEBUG: */
+    /* UNIMPL case SO_DONTROUTE: */
+    case SO_KEEPALIVE:
+    /* UNIMPL case SO_OOBINCLUDE: */
+#if SO_REUSE
+    case SO_REUSEADDR:
+    case SO_REUSEPORT:
+#endif /* SO_REUSE */
+    /* UNIMPL case SO_USELOOPBACK: */
+      if (*(int*)optval) {
+        sock->conn->pcb.ip->so_options |= optname;
+      } else {
+        sock->conn->pcb.ip->so_options &= ~optname;
+      }
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, SOL_SOCKET, optname=0x%x, ..) -> %s\n",
+                  s, optname, (*(int*)optval?"on":"off")));
+      break;
+#if LWIP_SO_RCVTIMEO
+    case SO_RCVTIMEO:
+      netconn_set_recvtimeout(sock->conn, *(int*)optval);
+      break;
+#endif /* LWIP_SO_RCVTIMEO */
+#if LWIP_SO_RCVBUF
+    case SO_RCVBUF:
+      netconn_set_recvbufsize(sock->conn, *(int*)optval);
+      break;
+#endif /* LWIP_SO_RCVBUF */
+#if LWIP_UDP
+    case SO_NO_CHECK:
+      if (*(int*)optval) {
+        udp_setflags(sock->conn->pcb.udp, udp_flags(sock->conn->pcb.udp) | UDP_FLAGS_NOCHKSUM);
+      } else {
+        udp_setflags(sock->conn->pcb.udp, udp_flags(sock->conn->pcb.udp) & ~UDP_FLAGS_NOCHKSUM);
+      }
+      break;
+#endif /* LWIP_UDP */
+    default:
+      LWIP_ASSERT("unhandled optname", 0);
+      break;
+    }  /* switch (optname) */
+    break;
+
+/* Level: IPPROTO_IP */
+  case IPPROTO_IP:
+    switch (optname) {
+    case IP_TTL:
+      sock->conn->pcb.ip->ttl = (u8_t)(*(int*)optval);
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_IP, IP_TTL, ..) -> %d\n",
+                  s, sock->conn->pcb.ip->ttl));
+      break;
+    case IP_TOS:
+      sock->conn->pcb.ip->tos = (u8_t)(*(int*)optval);
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_IP, IP_TOS, ..)-> %d\n",
+                  s, sock->conn->pcb.ip->tos));
+      break;
+#if LWIP_IGMP
+    case IP_MULTICAST_TTL:
+      sock->conn->pcb.udp->ttl = (u8_t)(*(u8_t*)optval);
+      break;
+    case IP_MULTICAST_IF:
+      inet_addr_to_ipaddr(&sock->conn->pcb.udp->multicast_ip, (struct in_addr*)optval);
+      break;
+    case IP_MULTICAST_LOOP:
+      if (*(u8_t*)optval) {
+        udp_setflags(sock->conn->pcb.udp, udp_flags(sock->conn->pcb.udp) | UDP_FLAGS_MULTICAST_LOOP);
+      } else {
+        udp_setflags(sock->conn->pcb.udp, udp_flags(sock->conn->pcb.udp) & ~UDP_FLAGS_MULTICAST_LOOP);
+      }
+      break;
+    case IP_ADD_MEMBERSHIP:
+    case IP_DROP_MEMBERSHIP:
+      {
+        /* If this is a TCP or a RAW socket, ignore these options. */
+        struct ip_mreq *imr = (struct ip_mreq *)optval;
+        ip_addr_t if_addr;
+        ip_addr_t multi_addr;
+        inet_addr_to_ipaddr(&if_addr, &imr->imr_interface);
+        inet_addr_to_ipaddr(&multi_addr, &imr->imr_multiaddr);
+        if(optname == IP_ADD_MEMBERSHIP){
+          data->err = igmp_joingroup(&if_addr, &multi_addr);
+        } else {
+          data->err = igmp_leavegroup(&if_addr, &multi_addr);
+        }
+        if(data->err != ERR_OK) {
+          data->err = EADDRNOTAVAIL;
+        }
+      }
+      break;
+#endif /* LWIP_IGMP */
+    default:
+      LWIP_ASSERT("unhandled optname", 0);
+      break;
+    }  /* switch (optname) */
+    break;
+
+#if LWIP_TCP
+/* Level: IPPROTO_TCP */
+  case IPPROTO_TCP:
+    switch (optname) {
+    case TCP_NODELAY:
+      if (*(int*)optval) {
+        tcp_nagle_disable(sock->conn->pcb.tcp);
+      } else {
+        tcp_nagle_enable(sock->conn->pcb.tcp);
+      }
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_TCP, TCP_NODELAY) -> %s\n",
+                  s, (*(int *)optval)?"on":"off") );
+      break;
+    case TCP_KEEPALIVE:
+      sock->conn->pcb.tcp->keep_idle = (u32_t)(*(int*)optval);
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_TCP, TCP_KEEPALIVE) -> %"U32_F"\n",
+                  s, sock->conn->pcb.tcp->keep_idle));
+      break;
+
+#if LWIP_TCP_KEEPALIVE
+    case TCP_KEEPIDLE:
+      sock->conn->pcb.tcp->keep_idle = 1000*(u32_t)(*(int*)optval);
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_TCP, TCP_KEEPIDLE) -> %"U32_F"\n",
+                  s, sock->conn->pcb.tcp->keep_idle));
+      break;
+    case TCP_KEEPINTVL:
+      sock->conn->pcb.tcp->keep_intvl = 1000*(u32_t)(*(int*)optval);
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_TCP, TCP_KEEPINTVL) -> %"U32_F"\n",
+                  s, sock->conn->pcb.tcp->keep_intvl));
+      break;
+    case TCP_KEEPCNT:
+      sock->conn->pcb.tcp->keep_cnt = (u32_t)(*(int*)optval);
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_TCP, TCP_KEEPCNT) -> %"U32_F"\n",
+                  s, sock->conn->pcb.tcp->keep_cnt));
+      break;
+#endif /* LWIP_TCP_KEEPALIVE */
+    default:
+      LWIP_ASSERT("unhandled optname", 0);
+      break;
+    }  /* switch (optname) */
+    break;
+#endif /* LWIP_TCP*/
+#if LWIP_UDP && LWIP_UDPLITE
+  /* Level: IPPROTO_UDPLITE */
+  case IPPROTO_UDPLITE:
+    switch (optname) {
+    case UDPLITE_SEND_CSCOV:
+      if ((*(int*)optval != 0) && ((*(int*)optval < 8)) || (*(int*)optval > 0xffff)) {
+        /* don't allow illegal values! */
+        sock->conn->pcb.udp->chksum_len_tx = 8;
+      } else {
+        sock->conn->pcb.udp->chksum_len_tx = (u16_t)*(int*)optval;
+      }
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_UDPLITE, UDPLITE_SEND_CSCOV) -> %d\n",
+                  s, (*(int*)optval)) );
+      break;
+    case UDPLITE_RECV_CSCOV:
+      if ((*(int*)optval != 0) && ((*(int*)optval < 8)) || (*(int*)optval > 0xffff)) {
+        /* don't allow illegal values! */
+        sock->conn->pcb.udp->chksum_len_rx = 8;
+      } else {
+        sock->conn->pcb.udp->chksum_len_rx = (u16_t)*(int*)optval;
+      }
+      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_UDPLITE, UDPLITE_RECV_CSCOV) -> %d\n",
+                  s, (*(int*)optval)) );
+      break;
+    default:
+      LWIP_ASSERT("unhandled optname", 0);
+      break;
+    }  /* switch (optname) */
+    break;
+#endif /* LWIP_UDP */
+  default:
+    LWIP_ASSERT("unhandled level", 0);
+    break;
+  }  /* switch (level) */
+  sys_sem_signal(&sock->conn->op_completed);
+}
+
+int
+lwip_ioctl(int s, long cmd, void *argp)
+{
+  struct lwip_sock *sock = get_socket(s);
+  u8_t val;
+#if LWIP_SO_RCVBUF
+  u16_t buflen = 0;
+  s16_t recv_avail;
+#endif /* LWIP_SO_RCVBUF */
+
+  if (!sock) {
+    return -1;
+  }
+
+  switch (cmd) {
+#if LWIP_SO_RCVBUF
+  case FIONREAD:
+    if (!argp) {
+      sock_set_errno(sock, EINVAL);
+      return -1;
+    }
+
+    SYS_ARCH_GET(sock->conn->recv_avail, recv_avail);
+    if (recv_avail < 0) {
+      recv_avail = 0;
+    }
+    *((u16_t*)argp) = (u16_t)recv_avail;
+
+    /* Check if there is data left from the last recv operation. /maq 041215 */
+    if (sock->lastdata) {
+      struct pbuf *p = (struct pbuf *)sock->lastdata;
+      if (netconn_type(sock->conn) != NETCONN_TCP) {
+        p = ((struct netbuf *)p)->p;
+      }
+      buflen = p->tot_len;
+      buflen -= sock->lastoffset;
+
+      *((u16_t*)argp) += buflen;
+    }
+
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_ioctl(%d, FIONREAD, %p) = %"U16_F"\n", s, argp, *((u16_t*)argp)));
+    sock_set_errno(sock, 0);
+    return 0;
+#endif /* LWIP_SO_RCVBUF */
+
+  case FIONBIO:
+    val = 0;
+    if (argp && *(u32_t*)argp) {
+      val = 1;
+    }
+    netconn_set_nonblocking(sock->conn, val);
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_ioctl(%d, FIONBIO, %d)\n", s, val));
+    sock_set_errno(sock, 0);
+    return 0;
+
+  default:
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_ioctl(%d, UNIMPL: 0x%lx, %p)\n", s, cmd, argp));
+    sock_set_errno(sock, ENOSYS); /* not yet implemented */
+    return -1;
+  } /* switch (cmd) */
+}
+
+/** A minimal implementation of fcntl.
+ * Currently only the commands F_GETFL and F_SETFL are implemented.
+ * Only the flag O_NONBLOCK is implemented.
+ */
+int
+lwip_fcntl(int s, int cmd, int val)
+{
+  struct lwip_sock *sock = get_socket(s);
+  int ret = -1;
+
+  if (!sock || !sock->conn) {
+    return -1;
+  }
+
+  switch (cmd) {
+  case F_GETFL:
+    ret = netconn_is_nonblocking(sock->conn) ? O_NONBLOCK : 0;
+    break;
+  case F_SETFL:
+    if ((val & ~O_NONBLOCK) == 0) {
+      /* only O_NONBLOCK, all other bits are zero */
+      netconn_set_nonblocking(sock->conn, val & O_NONBLOCK);
+      ret = 0;
+    }
+    break;
+  default:
+    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_fcntl(%d, UNIMPL: %d, %d)\n", s, cmd, val));
+    break;
+  }
+  return ret;
+}
+
+#endif /* LWIP_SOCKET */
diff --git a/core/lwip/src/api/tcpip.c b/core/lwip/src/api/tcpip.c
new file mode 100644
index 00000000..857e7d9b
--- /dev/null
+++ b/core/lwip/src/api/tcpip.c
@@ -0,0 +1,460 @@
+/**
+ * @file
+ * Sequential API Main thread module
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if !NO_SYS /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/sys.h"
+#include "lwip/memp.h"
+#include "lwip/mem.h"
+#include "lwip/pbuf.h"
+#include "lwip/tcpip.h"
+#include "lwip/init.h"
+#include "netif/etharp.h"
+#include "netif/ppp_oe.h"
+
+/* global variables */
+static tcpip_init_done_fn tcpip_init_done;
+static void *tcpip_init_done_arg;
+static sys_mbox_t mbox;
+
+#if LWIP_TCPIP_CORE_LOCKING
+/** The global semaphore to lock the stack. */
+sys_mutex_t lock_tcpip_core;
+#endif /* LWIP_TCPIP_CORE_LOCKING */
+
+
+/**
+ * The main lwIP thread. This thread has exclusive access to lwIP core functions
+ * (unless access to them is not locked). Other threads communicate with this
+ * thread using message boxes.
+ *
+ * It also starts all the timers to make sure they are running in the right
+ * thread context.
+ *
+ * @param arg unused argument
+ */
+static void
+tcpip_thread(void *arg)
+{
+  struct tcpip_msg *msg;
+  LWIP_UNUSED_ARG(arg);
+
+  if (tcpip_init_done != NULL) {
+    tcpip_init_done(tcpip_init_done_arg);
+  }
+
+  LOCK_TCPIP_CORE();
+  while (1) {                          /* MAIN Loop */
+    UNLOCK_TCPIP_CORE();
+    LWIP_TCPIP_THREAD_ALIVE();
+    /* wait for a message, timeouts are processed while waiting */
+    sys_timeouts_mbox_fetch(&mbox, (void **)&msg);
+    LOCK_TCPIP_CORE();
+    switch (msg->type) {
+#if LWIP_NETCONN
+    case TCPIP_MSG_API:
+      LWIP_DEBUGF(TCPIP_DEBUG, ("tcpip_thread: API message %p\n", (void *)msg));
+      msg->msg.apimsg->function(&(msg->msg.apimsg->msg));
+      break;
+#endif /* LWIP_NETCONN */
+
+#if !LWIP_TCPIP_CORE_LOCKING_INPUT
+    case TCPIP_MSG_INPKT:
+      LWIP_DEBUGF(TCPIP_DEBUG, ("tcpip_thread: PACKET %p\n", (void *)msg));
+#if LWIP_ETHERNET
+      if (msg->msg.inp.netif->flags & (NETIF_FLAG_ETHARP | NETIF_FLAG_ETHERNET)) {
+        ethernet_input(msg->msg.inp.p, msg->msg.inp.netif);
+      } else
+#endif /* LWIP_ETHERNET */
+      {
+        ip_input(msg->msg.inp.p, msg->msg.inp.netif);
+      }
+      memp_free(MEMP_TCPIP_MSG_INPKT, msg);
+      break;
+#endif /* LWIP_TCPIP_CORE_LOCKING_INPUT */
+
+#if LWIP_NETIF_API
+    case TCPIP_MSG_NETIFAPI:
+      LWIP_DEBUGF(TCPIP_DEBUG, ("tcpip_thread: Netif API message %p\n", (void *)msg));
+      msg->msg.netifapimsg->function(&(msg->msg.netifapimsg->msg));
+      break;
+#endif /* LWIP_NETIF_API */
+
+    case TCPIP_MSG_CALLBACK:
+      LWIP_DEBUGF(TCPIP_DEBUG, ("tcpip_thread: CALLBACK %p\n", (void *)msg));
+      msg->msg.cb.function(msg->msg.cb.ctx);
+      memp_free(MEMP_TCPIP_MSG_API, msg);
+      break;
+
+#if LWIP_TCPIP_TIMEOUT
+    case TCPIP_MSG_TIMEOUT:
+      LWIP_DEBUGF(TCPIP_DEBUG, ("tcpip_thread: TIMEOUT %p\n", (void *)msg));
+      sys_timeout(msg->msg.tmo.msecs, msg->msg.tmo.h, msg->msg.tmo.arg);
+      memp_free(MEMP_TCPIP_MSG_API, msg);
+      break;
+    case TCPIP_MSG_UNTIMEOUT:
+      LWIP_DEBUGF(TCPIP_DEBUG, ("tcpip_thread: UNTIMEOUT %p\n", (void *)msg));
+      sys_untimeout(msg->msg.tmo.h, msg->msg.tmo.arg);
+      memp_free(MEMP_TCPIP_MSG_API, msg);
+      break;
+#endif /* LWIP_TCPIP_TIMEOUT */
+
+    default:
+      LWIP_DEBUGF(TCPIP_DEBUG, ("tcpip_thread: invalid message: %d\n", msg->type));
+      LWIP_ASSERT("tcpip_thread: invalid message", 0);
+      break;
+    }
+  }
+}
+
+/**
+ * Pass a received packet to tcpip_thread for input processing
+ *
+ * @param p the received packet, p->payload pointing to the Ethernet header or
+ *          to an IP header (if inp doesn't have NETIF_FLAG_ETHARP or
+ *          NETIF_FLAG_ETHERNET flags)
+ * @param inp the network interface on which the packet was received
+ */
+err_t
+tcpip_input(struct pbuf *p, struct netif *inp)
+{
+#if LWIP_TCPIP_CORE_LOCKING_INPUT
+  err_t ret;
+  LWIP_DEBUGF(TCPIP_DEBUG, ("tcpip_input: PACKET %p/%p\n", (void *)p, (void *)inp));
+  LOCK_TCPIP_CORE();
+#if LWIP_ETHERNET
+  if (inp->flags & (NETIF_FLAG_ETHARP | NETIF_FLAG_ETHERNET)) {
+    ret = ethernet_input(p, inp);
+  } else
+#endif /* LWIP_ETHERNET */
+  {
+    ret = ip_input(p, inp);
+  }
+  UNLOCK_TCPIP_CORE();
+  return ret;
+#else /* LWIP_TCPIP_CORE_LOCKING_INPUT */
+  struct tcpip_msg *msg;
+
+  if (sys_mbox_valid(&mbox)) {
+    msg = (struct tcpip_msg *)memp_malloc(MEMP_TCPIP_MSG_INPKT);
+    if (msg == NULL) {
+      return ERR_MEM;
+    }
+
+    msg->type = TCPIP_MSG_INPKT;
+    msg->msg.inp.p = p;
+    msg->msg.inp.netif = inp;
+    if (sys_mbox_trypost(&mbox, msg) != ERR_OK) {
+      memp_free(MEMP_TCPIP_MSG_INPKT, msg);
+      return ERR_MEM;
+    }
+    return ERR_OK;
+  }
+  return ERR_VAL;
+#endif /* LWIP_TCPIP_CORE_LOCKING_INPUT */
+}
+
+/**
+ * Call a specific function in the thread context of
+ * tcpip_thread for easy access synchronization.
+ * A function called in that way may access lwIP core code
+ * without fearing concurrent access.
+ *
+ * @param f the function to call
+ * @param ctx parameter passed to f
+ * @param block 1 to block until the request is posted, 0 to non-blocking mode
+ * @return ERR_OK if the function was called, another err_t if not
+ */
+err_t
+tcpip_callback_with_block(tcpip_callback_fn function, void *ctx, u8_t block)
+{
+  struct tcpip_msg *msg;
+
+  if (sys_mbox_valid(&mbox)) {
+    msg = (struct tcpip_msg *)memp_malloc(MEMP_TCPIP_MSG_API);
+    if (msg == NULL) {
+      return ERR_MEM;
+    }
+
+    msg->type = TCPIP_MSG_CALLBACK;
+    msg->msg.cb.function = function;
+    msg->msg.cb.ctx = ctx;
+    if (block) {
+      sys_mbox_post(&mbox, msg);
+    } else {
+      if (sys_mbox_trypost(&mbox, msg) != ERR_OK) {
+        memp_free(MEMP_TCPIP_MSG_API, msg);
+        return ERR_MEM;
+      }
+    }
+    return ERR_OK;
+  }
+  return ERR_VAL;
+}
+
+#if LWIP_TCPIP_TIMEOUT
+/**
+ * call sys_timeout in tcpip_thread
+ *
+ * @param msec time in milliseconds for timeout
+ * @param h function to be called on timeout
+ * @param arg argument to pass to timeout function h
+ * @return ERR_MEM on memory error, ERR_OK otherwise
+ */
+err_t
+tcpip_timeout(u32_t msecs, sys_timeout_handler h, void *arg)
+{
+  struct tcpip_msg *msg;
+
+  if (sys_mbox_valid(&mbox)) {
+    msg = (struct tcpip_msg *)memp_malloc(MEMP_TCPIP_MSG_API);
+    if (msg == NULL) {
+      return ERR_MEM;
+    }
+
+    msg->type = TCPIP_MSG_TIMEOUT;
+    msg->msg.tmo.msecs = msecs;
+    msg->msg.tmo.h = h;
+    msg->msg.tmo.arg = arg;
+    sys_mbox_post(&mbox, msg);
+    return ERR_OK;
+  }
+  return ERR_VAL;
+}
+
+/**
+ * call sys_untimeout in tcpip_thread
+ *
+ * @param msec time in milliseconds for timeout
+ * @param h function to be called on timeout
+ * @param arg argument to pass to timeout function h
+ * @return ERR_MEM on memory error, ERR_OK otherwise
+ */
+err_t
+tcpip_untimeout(sys_timeout_handler h, void *arg)
+{
+  struct tcpip_msg *msg;
+
+  if (sys_mbox_valid(&mbox)) {
+    msg = (struct tcpip_msg *)memp_malloc(MEMP_TCPIP_MSG_API);
+    if (msg == NULL) {
+      return ERR_MEM;
+    }
+
+    msg->type = TCPIP_MSG_UNTIMEOUT;
+    msg->msg.tmo.h = h;
+    msg->msg.tmo.arg = arg;
+    sys_mbox_post(&mbox, msg);
+    return ERR_OK;
+  }
+  return ERR_VAL;
+}
+#endif /* LWIP_TCPIP_TIMEOUT */
+
+#if LWIP_NETCONN
+/**
+ * Call the lower part of a netconn_* function
+ * This function is then running in the thread context
+ * of tcpip_thread and has exclusive access to lwIP core code.
+ *
+ * @param apimsg a struct containing the function to call and its parameters
+ * @return ERR_OK if the function was called, another err_t if not
+ */
+err_t
+tcpip_apimsg(struct api_msg *apimsg)
+{
+  struct tcpip_msg msg;
+#ifdef LWIP_DEBUG
+  /* catch functions that don't set err */
+  apimsg->msg.err = ERR_VAL;
+#endif
+  
+  if (sys_mbox_valid(&mbox)) {
+    msg.type = TCPIP_MSG_API;
+    msg.msg.apimsg = apimsg;
+    sys_mbox_post(&mbox, &msg);
+    sys_arch_sem_wait(&apimsg->msg.conn->op_completed, 0);
+    return apimsg->msg.err;
+  }
+  return ERR_VAL;
+}
+
+#if LWIP_TCPIP_CORE_LOCKING
+/**
+ * Call the lower part of a netconn_* function
+ * This function has exclusive access to lwIP core code by locking it
+ * before the function is called.
+ *
+ * @param apimsg a struct containing the function to call and its parameters
+ * @return ERR_OK (only for compatibility fo tcpip_apimsg())
+ */
+err_t
+tcpip_apimsg_lock(struct api_msg *apimsg)
+{
+#ifdef LWIP_DEBUG
+  /* catch functions that don't set err */
+  apimsg->msg.err = ERR_VAL;
+#endif
+
+  LOCK_TCPIP_CORE();
+  apimsg->function(&(apimsg->msg));
+  UNLOCK_TCPIP_CORE();
+  return apimsg->msg.err;
+
+}
+#endif /* LWIP_TCPIP_CORE_LOCKING */
+#endif /* LWIP_NETCONN */
+
+#if LWIP_NETIF_API
+#if !LWIP_TCPIP_CORE_LOCKING
+/**
+ * Much like tcpip_apimsg, but calls the lower part of a netifapi_*
+ * function.
+ *
+ * @param netifapimsg a struct containing the function to call and its parameters
+ * @return error code given back by the function that was called
+ */
+err_t
+tcpip_netifapi(struct netifapi_msg* netifapimsg)
+{
+  struct tcpip_msg msg;
+  
+  if (sys_mbox_valid(&mbox)) {
+    err_t err = sys_sem_new(&netifapimsg->msg.sem, 0);
+    if (err != ERR_OK) {
+      netifapimsg->msg.err = err;
+      return err;
+    }
+    
+    msg.type = TCPIP_MSG_NETIFAPI;
+    msg.msg.netifapimsg = netifapimsg;
+    sys_mbox_post(&mbox, &msg);
+    sys_sem_wait(&netifapimsg->msg.sem);
+    sys_sem_free(&netifapimsg->msg.sem);
+    return netifapimsg->msg.err;
+  }
+  return ERR_VAL;
+}
+#else /* !LWIP_TCPIP_CORE_LOCKING */
+/**
+ * Call the lower part of a netifapi_* function
+ * This function has exclusive access to lwIP core code by locking it
+ * before the function is called.
+ *
+ * @param netifapimsg a struct containing the function to call and its parameters
+ * @return ERR_OK (only for compatibility fo tcpip_netifapi())
+ */
+err_t
+tcpip_netifapi_lock(struct netifapi_msg* netifapimsg)
+{
+  LOCK_TCPIP_CORE();  
+  netifapimsg->function(&(netifapimsg->msg));
+  UNLOCK_TCPIP_CORE();
+  return netifapimsg->msg.err;
+}
+#endif /* !LWIP_TCPIP_CORE_LOCKING */
+#endif /* LWIP_NETIF_API */
+
+/**
+ * Initialize this module:
+ * - initialize all sub modules
+ * - start the tcpip_thread
+ *
+ * @param initfunc a function to call when tcpip_thread is running and finished initializing
+ * @param arg argument to pass to initfunc
+ */
+void
+tcpip_init(tcpip_init_done_fn initfunc, void *arg)
+{
+  lwip_init();
+
+  tcpip_init_done = initfunc;
+  tcpip_init_done_arg = arg;
+  if(sys_mbox_new(&mbox, TCPIP_MBOX_SIZE) != ERR_OK) {
+    LWIP_ASSERT("failed to create tcpip_thread mbox", 0);
+  }
+#if LWIP_TCPIP_CORE_LOCKING
+  if(sys_mutex_new(&lock_tcpip_core) != ERR_OK) {
+    LWIP_ASSERT("failed to create lock_tcpip_core", 0);
+  }
+#endif /* LWIP_TCPIP_CORE_LOCKING */
+
+  sys_thread_new(TCPIP_THREAD_NAME, tcpip_thread, NULL, TCPIP_THREAD_STACKSIZE, TCPIP_THREAD_PRIO);
+}
+
+/**
+ * Simple callback function used with tcpip_callback to free a pbuf
+ * (pbuf_free has a wrong signature for tcpip_callback)
+ *
+ * @param p The pbuf (chain) to be dereferenced.
+ */
+static void
+pbuf_free_int(void *p)
+{
+  struct pbuf *q = (struct pbuf *)p;
+  pbuf_free(q);
+}
+
+/**
+ * A simple wrapper function that allows you to free a pbuf from interrupt context.
+ *
+ * @param p The pbuf (chain) to be dereferenced.
+ * @return ERR_OK if callback could be enqueued, an err_t if not
+ */
+err_t
+pbuf_free_callback(struct pbuf *p)
+{
+  return tcpip_callback_with_block(pbuf_free_int, p, 0);
+}
+
+/**
+ * A simple wrapper function that allows you to free heap memory from
+ * interrupt context.
+ *
+ * @param m the heap memory to free
+ * @return ERR_OK if callback could be enqueued, an err_t if not
+ */
+err_t
+mem_free_callback(void *m)
+{
+  return tcpip_callback_with_block(mem_free, m, 0);
+}
+
+#endif /* !NO_SYS */
diff --git a/core/lwip/src/arch/sys_arch.c b/core/lwip/src/arch/sys_arch.c
new file mode 100644
index 00000000..894f6ada
--- /dev/null
+++ b/core/lwip/src/arch/sys_arch.c
@@ -0,0 +1,128 @@
+#include "arch/sys_arch.h"
+#include "lwip/sys.h"
+#include "lwip/mem.h"
+#include <stdlib.h>
+#include <thread.h>
+
+void sys_init(void)
+{
+}
+
+err_t sys_sem_new(sys_sem_t *sem, u8_t count)
+{
+    if (!sem)
+	return EINVAL;
+    *sem = malloc(sizeof(struct semaphore));
+    if (!*sem)
+	return ENOMEM;
+
+    sem_init(*sem, count);
+    return 0;
+}
+
+void sys_sem_free(sys_sem_t *sem)
+{
+    if (!!sem && !!*sem) {
+	sys_sem_set_invalid(sem);
+	free(*sem);
+	*sem = NULL;
+    }
+}
+
+void sys_sem_set_invalid(sys_sem_t *sem)
+{
+    if (!sem || !*sem)
+	return;
+    sem_set_invalid(*sem);
+}
+
+
+int sys_sem_valid(sys_sem_t *sem)
+{
+    if (!sem || !*sem)
+	return 0;
+    return sem_is_valid(*sem);
+}
+
+u32_t sys_arch_sem_wait(sys_sem_t *sem, u32_t timeout)
+{
+    mstime_t rv;
+
+    if (!!sem)
+	return SYS_ARCH_TIMEOUT;
+    rv = sem_down(*sem, timeout);
+    if (rv == (mstime_t)-1)
+	return SYS_ARCH_TIMEOUT;
+    else
+	return rv;
+}
+
+err_t sys_mbox_new(sys_mbox_t *mbox, int size)
+{
+    if (!mbox)
+	return EINVAL;
+    *mbox = malloc(MBOX_BYTES(size));
+    if (!(*mbox))
+	return ENOMEM;
+
+    mbox_init(*mbox, size);
+    return 0;
+}
+
+void sys_mbox_free(sys_mbox_t *mbox)
+{
+    if (!!mbox && !!*mbox)
+	free(*mbox);
+}
+
+void sys_mbox_post(sys_mbox_t *mbox, void *msg)
+{
+    if (!!mbox)
+	mbox_post(*mbox, msg, 0);
+}
+
+err_t sys_mbox_trypost(sys_mbox_t *mbox, void *msg)
+{
+    if (!mbox)
+	return EINVAL;
+    return mbox_post(*mbox, msg, -1);
+}
+
+u32_t sys_arch_mbox_fetch(sys_mbox_t *mbox, void **msg, u32_t timeout)
+{
+    mstime_t rv;
+
+    if (!mbox)
+	return SYS_MBOX_EMPTY;
+    rv = mbox_fetch(*mbox, msg, timeout);
+    if (rv == (mstime_t)-1)
+	return SYS_ARCH_TIMEOUT;
+    else
+	return rv;
+}
+
+u32_t sys_arch_mbox_tryfetch(sys_mbox_t *mbox, void **msg)
+{
+    if (!mbox)
+	return SYS_MBOX_EMPTY;
+    return mbox_fetch(*mbox, msg, -1);
+}
+
+void sys_mbox_set_invalid(sys_mbox_t *mbox)
+{
+    if (!!mbox)
+	mbox_set_invalid(*mbox);
+}
+
+int sys_mbox_valid(sys_mbox_t *mbox)
+{
+    return ((!!mbox) && mbox_is_valid(*mbox));
+}
+
+
+sys_thread_t sys_thread_new(const char *name, lwip_thread_fn thread,
+			    void *arg, int stacksize, int prio)
+{
+    return start_thread(name, stacksize, prio, thread, arg);
+}
+
diff --git a/core/lwip/src/core/def.c b/core/lwip/src/core/def.c
new file mode 100644
index 00000000..352b5524
--- /dev/null
+++ b/core/lwip/src/core/def.c
@@ -0,0 +1,108 @@
+/**
+ * @file
+ * Common functions used throughout the stack.
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Simon Goldschmidt
+ *
+ */
+
+#include "lwip/opt.h"
+#include "lwip/def.h"
+
+/**
+ * These are reference implementations of the byte swapping functions.
+ * Again with the aim of being simple, correct and fully portable.
+ * Byte swapping is the second thing you would want to optimize. You will
+ * need to port it to your architecture and in your cc.h:
+ * 
+ * #define LWIP_PLATFORM_BYTESWAP 1
+ * #define LWIP_PLATFORM_HTONS(x) <your_htons>
+ * #define LWIP_PLATFORM_HTONL(x) <your_htonl>
+ *
+ * Note ntohs() and ntohl() are merely references to the htonx counterparts.
+ */
+
+#if (LWIP_PLATFORM_BYTESWAP == 0) && (BYTE_ORDER == LITTLE_ENDIAN)
+
+/**
+ * Convert an u16_t from host- to network byte order.
+ *
+ * @param n u16_t in host byte order
+ * @return n in network byte order
+ */
+u16_t
+lwip_htons(u16_t n)
+{
+  return ((n & 0xff) << 8) | ((n & 0xff00) >> 8);
+}
+
+/**
+ * Convert an u16_t from network- to host byte order.
+ *
+ * @param n u16_t in network byte order
+ * @return n in host byte order
+ */
+u16_t
+lwip_ntohs(u16_t n)
+{
+  return lwip_htons(n);
+}
+
+/**
+ * Convert an u32_t from host- to network byte order.
+ *
+ * @param n u32_t in host byte order
+ * @return n in network byte order
+ */
+u32_t
+lwip_htonl(u32_t n)
+{
+  return ((n & 0xff) << 24) |
+    ((n & 0xff00) << 8) |
+    ((n & 0xff0000UL) >> 8) |
+    ((n & 0xff000000UL) >> 24);
+}
+
+/**
+ * Convert an u32_t from network- to host byte order.
+ *
+ * @param n u32_t in network byte order
+ * @return n in host byte order
+ */
+u32_t
+lwip_ntohl(u32_t n)
+{
+  return lwip_htonl(n);
+}
+
+#endif /* (LWIP_PLATFORM_BYTESWAP == 0) && (BYTE_ORDER == LITTLE_ENDIAN) */
diff --git a/core/lwip/src/core/dhcp.c b/core/lwip/src/core/dhcp.c
new file mode 100644
index 00000000..81b4be27
--- /dev/null
+++ b/core/lwip/src/core/dhcp.c
@@ -0,0 +1,1745 @@
+/**
+ * @file
+ * Dynamic Host Configuration Protocol client
+ *
+ */
+
+/*
+ *
+ * Copyright (c) 2001-2004 Leon Woestenberg <leon.woestenberg@gmx.net>
+ * Copyright (c) 2001-2004 Axon Digital Design B.V., The Netherlands.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is a contribution to the lwIP TCP/IP stack.
+ * The Swedish Institute of Computer Science and Adam Dunkels
+ * are specifically granted permission to redistribute this
+ * source code.
+ *
+ * Author: Leon Woestenberg <leon.woestenberg@gmx.net>
+ *
+ * This is a DHCP client for the lwIP TCP/IP stack. It aims to conform
+ * with RFC 2131 and RFC 2132.
+ *
+ * TODO:
+ * - Support for interfaces other than Ethernet (SLIP, PPP, ...)
+ *
+ * Please coordinate changes and requests with Leon Woestenberg
+ * <leon.woestenberg@gmx.net>
+ *
+ * Integration with your code:
+ *
+ * In lwip/dhcp.h
+ * #define DHCP_COARSE_TIMER_SECS (recommended 60 which is a minute)
+ * #define DHCP_FINE_TIMER_MSECS (recommended 500 which equals TCP coarse timer)
+ *
+ * Then have your application call dhcp_coarse_tmr() and
+ * dhcp_fine_tmr() on the defined intervals.
+ *
+ * dhcp_start(struct netif *netif);
+ * starts a DHCP client instance which configures the interface by
+ * obtaining an IP address lease and maintaining it.
+ *
+ * Use dhcp_release(netif) to end the lease and use dhcp_stop(netif)
+ * to remove the DHCP client.
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_DHCP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/stats.h"
+#include "lwip/mem.h"
+#include "lwip/udp.h"
+#include "lwip/ip_addr.h"
+#include "lwip/netif.h"
+#include "lwip/def.h"
+#include "lwip/sys.h"
+#include "lwip/dhcp.h"
+#include "lwip/autoip.h"
+#include "lwip/dns.h"
+#include "netif/etharp.h"
+
+#include <string.h>
+
+/** Default for DHCP_GLOBAL_XID is 0xABCD0000
+ * This can be changed by defining DHCP_GLOBAL_XID and DHCP_GLOBAL_XID_HEADER, e.g.
+ *  #define DHCP_GLOBAL_XID_HEADER "stdlib.h"
+ *  #define DHCP_GLOBAL_XID rand()
+ */
+#ifdef DHCP_GLOBAL_XID_HEADER
+#include DHCP_GLOBAL_XID_HEADER /* include optional starting XID generation prototypes */
+#endif
+
+/** DHCP_OPTION_MAX_MSG_SIZE is set to the MTU
+ * MTU is checked to be big enough in dhcp_start */
+#define DHCP_MAX_MSG_LEN(netif)        (netif->mtu)
+#define DHCP_MAX_MSG_LEN_MIN_REQUIRED  576
+/** Minimum length for reply before packet is parsed */
+#define DHCP_MIN_REPLY_LEN             44
+
+#define REBOOT_TRIES 2
+
+/** Option handling: options are parsed in dhcp_parse_reply
+ * and saved in an array where other functions can load them from.
+ * This might be moved into the struct dhcp (not necessarily since
+ * lwIP is single-threaded and the array is only used while in recv
+ * callback). */
+#define DHCP_OPTION_IDX_OVERLOAD    0
+#define DHCP_OPTION_IDX_MSG_TYPE    1
+#define DHCP_OPTION_IDX_SERVER_ID   2
+#define DHCP_OPTION_IDX_LEASE_TIME  3
+#define DHCP_OPTION_IDX_T1          4
+#define DHCP_OPTION_IDX_T2          5
+#define DHCP_OPTION_IDX_SUBNET_MASK 6
+#define DHCP_OPTION_IDX_ROUTER      7
+#define DHCP_OPTION_IDX_DNS_SERVER	8
+#define DHCP_OPTION_IDX_MAX         (DHCP_OPTION_IDX_DNS_SERVER + DNS_MAX_SERVERS)
+
+/** Holds the decoded option values, only valid while in dhcp_recv.
+    @todo: move this into struct dhcp? */
+u32_t dhcp_rx_options_val[DHCP_OPTION_IDX_MAX];
+/** Holds a flag which option was received and is contained in dhcp_rx_options_val,
+    only valid while in dhcp_recv.
+    @todo: move this into struct dhcp? */
+u8_t  dhcp_rx_options_given[DHCP_OPTION_IDX_MAX];
+
+#define dhcp_option_given(dhcp, idx)          (dhcp_rx_options_given[idx] != 0)
+#define dhcp_got_option(dhcp, idx)            (dhcp_rx_options_given[idx] = 1)
+#define dhcp_clear_option(dhcp, idx)          (dhcp_rx_options_given[idx] = 0)
+#define dhcp_clear_all_options(dhcp)          (memset(dhcp_rx_options_given, 0, sizeof(dhcp_rx_options_given)))
+#define dhcp_get_option_value(dhcp, idx)      (dhcp_rx_options_val[idx])
+#define dhcp_set_option_value(dhcp, idx, val) (dhcp_rx_options_val[idx] = (val))
+
+
+/* DHCP client state machine functions */
+static err_t dhcp_discover(struct netif *netif);
+static err_t dhcp_select(struct netif *netif);
+static void dhcp_bind(struct netif *netif);
+#if DHCP_DOES_ARP_CHECK
+static err_t dhcp_decline(struct netif *netif);
+#endif /* DHCP_DOES_ARP_CHECK */
+static err_t dhcp_rebind(struct netif *netif);
+static err_t dhcp_reboot(struct netif *netif);
+static void dhcp_set_state(struct dhcp *dhcp, u8_t new_state);
+
+/* receive, unfold, parse and free incoming messages */
+static void dhcp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port);
+
+/* set the DHCP timers */
+static void dhcp_timeout(struct netif *netif);
+static void dhcp_t1_timeout(struct netif *netif);
+static void dhcp_t2_timeout(struct netif *netif);
+
+/* build outgoing messages */
+/* create a DHCP message, fill in common headers */
+static err_t dhcp_create_msg(struct netif *netif, struct dhcp *dhcp, u8_t message_type);
+/* free a DHCP request */
+static void dhcp_delete_msg(struct dhcp *dhcp);
+/* add a DHCP option (type, then length in bytes) */
+static void dhcp_option(struct dhcp *dhcp, u8_t option_type, u8_t option_len);
+/* add option values */
+static void dhcp_option_byte(struct dhcp *dhcp, u8_t value);
+static void dhcp_option_short(struct dhcp *dhcp, u16_t value);
+static void dhcp_option_long(struct dhcp *dhcp, u32_t value);
+/* always add the DHCP options trailer to end and pad */
+static void dhcp_option_trailer(struct dhcp *dhcp);
+
+/**
+ * Back-off the DHCP client (because of a received NAK response).
+ *
+ * Back-off the DHCP client because of a received NAK. Receiving a
+ * NAK means the client asked for something non-sensible, for
+ * example when it tries to renew a lease obtained on another network.
+ *
+ * We clear any existing set IP address and restart DHCP negotiation
+ * afresh (as per RFC2131 3.2.3).
+ *
+ * @param netif the netif under DHCP control
+ */
+static void
+dhcp_handle_nak(struct netif *netif)
+{
+  struct dhcp *dhcp = netif->dhcp;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_handle_nak(netif=%p) %c%c%"U16_F"\n", 
+    (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
+  /* Set the interface down since the address must no longer be used, as per RFC2131 */
+  netif_set_down(netif);
+  /* remove IP address from interface */
+  netif_set_ipaddr(netif, IP_ADDR_ANY);
+  netif_set_gw(netif, IP_ADDR_ANY);
+  netif_set_netmask(netif, IP_ADDR_ANY); 
+  /* Change to a defined state */
+  dhcp_set_state(dhcp, DHCP_BACKING_OFF);
+  /* We can immediately restart discovery */
+  dhcp_discover(netif);
+}
+
+#if DHCP_DOES_ARP_CHECK
+/**
+ * Checks if the offered IP address is already in use.
+ *
+ * It does so by sending an ARP request for the offered address and
+ * entering CHECKING state. If no ARP reply is received within a small
+ * interval, the address is assumed to be free for use by us.
+ *
+ * @param netif the netif under DHCP control
+ */
+static void
+dhcp_check(struct netif *netif)
+{
+  struct dhcp *dhcp = netif->dhcp;
+  err_t result;
+  u16_t msecs;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_check(netif=%p) %c%c\n", (void *)netif, (s16_t)netif->name[0],
+    (s16_t)netif->name[1]));
+  dhcp_set_state(dhcp, DHCP_CHECKING);
+  /* create an ARP query for the offered IP address, expecting that no host
+     responds, as the IP address should not be in use. */
+  result = etharp_query(netif, &dhcp->offered_ip_addr, NULL);
+  if (result != ERR_OK) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("dhcp_check: could not perform ARP query\n"));
+  }
+  dhcp->tries++;
+  msecs = 500;
+  dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_check(): set request timeout %"U16_F" msecs\n", msecs));
+}
+#endif /* DHCP_DOES_ARP_CHECK */
+
+/**
+ * Remember the configuration offered by a DHCP server.
+ *
+ * @param netif the netif under DHCP control
+ */
+static void
+dhcp_handle_offer(struct netif *netif)
+{
+  struct dhcp *dhcp = netif->dhcp;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_handle_offer(netif=%p) %c%c%"U16_F"\n",
+    (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
+  /* obtain the server address */
+  if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_SERVER_ID)) {
+    ip4_addr_set_u32(&dhcp->server_ip_addr, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_SERVER_ID)));
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_handle_offer(): server 0x%08"X32_F"\n",
+      ip4_addr_get_u32(&dhcp->server_ip_addr)));
+    /* remember offered address */
+    ip_addr_copy(dhcp->offered_ip_addr, dhcp->msg_in->yiaddr);
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_handle_offer(): offer for 0x%08"X32_F"\n",
+      ip4_addr_get_u32(&dhcp->offered_ip_addr)));
+
+    dhcp_select(netif);
+  } else {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
+      ("dhcp_handle_offer(netif=%p) did not get server ID!\n", (void*)netif));
+  }
+}
+
+/**
+ * Select a DHCP server offer out of all offers.
+ *
+ * Simply select the first offer received.
+ *
+ * @param netif the netif under DHCP control
+ * @return lwIP specific error (see error.h)
+ */
+static err_t
+dhcp_select(struct netif *netif)
+{
+  struct dhcp *dhcp = netif->dhcp;
+  err_t result;
+  u16_t msecs;
+
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_select(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
+  dhcp_set_state(dhcp, DHCP_REQUESTING);
+
+  /* create and initialize the DHCP message header */
+  result = dhcp_create_msg(netif, dhcp, DHCP_REQUEST);
+  if (result == ERR_OK) {
+    dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
+    dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
+
+    /* MUST request the offered IP address */
+    dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
+    dhcp_option_long(dhcp, ntohl(ip4_addr_get_u32(&dhcp->offered_ip_addr)));
+
+    dhcp_option(dhcp, DHCP_OPTION_SERVER_ID, 4);
+    dhcp_option_long(dhcp, ntohl(ip4_addr_get_u32(&dhcp->server_ip_addr)));
+
+    dhcp_option(dhcp, DHCP_OPTION_PARAMETER_REQUEST_LIST, 4/*num options*/);
+    dhcp_option_byte(dhcp, DHCP_OPTION_SUBNET_MASK);
+    dhcp_option_byte(dhcp, DHCP_OPTION_ROUTER);
+    dhcp_option_byte(dhcp, DHCP_OPTION_BROADCAST);
+    dhcp_option_byte(dhcp, DHCP_OPTION_DNS_SERVER);
+
+#if LWIP_NETIF_HOSTNAME
+    if (netif->hostname != NULL) {
+      const char *p = (const char*)netif->hostname;
+      u8_t namelen = (u8_t)strlen(p);
+      if (namelen > 0) {
+        LWIP_ASSERT("DHCP: hostname is too long!", namelen < 255);
+        dhcp_option(dhcp, DHCP_OPTION_HOSTNAME, namelen);
+        while (*p) {
+          dhcp_option_byte(dhcp, *p++);
+        }
+      }
+    }
+#endif /* LWIP_NETIF_HOSTNAME */
+
+    dhcp_option_trailer(dhcp);
+    /* shrink the pbuf to the actual content length */
+    pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
+
+    /* send broadcast to any DHCP server */
+    udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
+    dhcp_delete_msg(dhcp);
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_select: REQUESTING\n"));
+  } else {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("dhcp_select: could not allocate DHCP request\n"));
+  }
+  dhcp->tries++;
+  msecs = (dhcp->tries < 6 ? 1 << dhcp->tries : 60) * 1000;
+  dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_select(): set request timeout %"U16_F" msecs\n", msecs));
+  return result;
+}
+
+/**
+ * The DHCP timer that checks for lease renewal/rebind timeouts.
+ */
+void
+dhcp_coarse_tmr()
+{
+  struct netif *netif = netif_list;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_coarse_tmr()\n"));
+  /* iterate through all network interfaces */
+  while (netif != NULL) {
+    /* only act on DHCP configured interfaces */
+    if (netif->dhcp != NULL) {
+      /* timer is active (non zero), and triggers (zeroes) now? */
+      if (netif->dhcp->t2_timeout-- == 1) {
+        LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_coarse_tmr(): t2 timeout\n"));
+        /* this clients' rebind timeout triggered */
+        dhcp_t2_timeout(netif);
+      /* timer is active (non zero), and triggers (zeroes) now */
+      } else if (netif->dhcp->t1_timeout-- == 1) {
+        LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_coarse_tmr(): t1 timeout\n"));
+        /* this clients' renewal timeout triggered */
+        dhcp_t1_timeout(netif);
+      }
+    }
+    /* proceed to next netif */
+    netif = netif->next;
+  }
+}
+
+/**
+ * DHCP transaction timeout handling
+ *
+ * A DHCP server is expected to respond within a short period of time.
+ * This timer checks whether an outstanding DHCP request is timed out.
+ */
+void
+dhcp_fine_tmr()
+{
+  struct netif *netif = netif_list;
+  /* loop through netif's */
+  while (netif != NULL) {
+    /* only act on DHCP configured interfaces */
+    if (netif->dhcp != NULL) {
+      /* timer is active (non zero), and is about to trigger now */      
+      if (netif->dhcp->request_timeout > 1) {
+        netif->dhcp->request_timeout--;
+      }
+      else if (netif->dhcp->request_timeout == 1) {
+        netif->dhcp->request_timeout--;
+        /* { netif->dhcp->request_timeout == 0 } */
+        LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_fine_tmr(): request timeout\n"));
+        /* this client's request timeout triggered */
+        dhcp_timeout(netif);
+      }
+    }
+    /* proceed to next network interface */
+    netif = netif->next;
+  }
+}
+
+/**
+ * A DHCP negotiation transaction, or ARP request, has timed out.
+ *
+ * The timer that was started with the DHCP or ARP request has
+ * timed out, indicating no response was received in time.
+ *
+ * @param netif the netif under DHCP control
+ */
+static void
+dhcp_timeout(struct netif *netif)
+{
+  struct dhcp *dhcp = netif->dhcp;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_timeout()\n"));
+  /* back-off period has passed, or server selection timed out */
+  if ((dhcp->state == DHCP_BACKING_OFF) || (dhcp->state == DHCP_SELECTING)) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_timeout(): restarting discovery\n"));
+    dhcp_discover(netif);
+  /* receiving the requested lease timed out */
+  } else if (dhcp->state == DHCP_REQUESTING) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): REQUESTING, DHCP request timed out\n"));
+    if (dhcp->tries <= 5) {
+      dhcp_select(netif);
+    } else {
+      LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): REQUESTING, releasing, restarting\n"));
+      dhcp_release(netif);
+      dhcp_discover(netif);
+    }
+#if DHCP_DOES_ARP_CHECK
+  /* received no ARP reply for the offered address (which is good) */
+  } else if (dhcp->state == DHCP_CHECKING) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): CHECKING, ARP request timed out\n"));
+    if (dhcp->tries <= 1) {
+      dhcp_check(netif);
+    /* no ARP replies on the offered address,
+       looks like the IP address is indeed free */
+    } else {
+      /* bind the interface to the offered address */
+      dhcp_bind(netif);
+    }
+#endif /* DHCP_DOES_ARP_CHECK */
+  }
+  /* did not get response to renew request? */
+  else if (dhcp->state == DHCP_RENEWING) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): RENEWING, DHCP request timed out\n"));
+    /* just retry renewal */
+    /* note that the rebind timer will eventually time-out if renew does not work */
+    dhcp_renew(netif);
+  /* did not get response to rebind request? */
+  } else if (dhcp->state == DHCP_REBINDING) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): REBINDING, DHCP request timed out\n"));
+    if (dhcp->tries <= 8) {
+      dhcp_rebind(netif);
+    } else {
+      LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): RELEASING, DISCOVERING\n"));
+      dhcp_release(netif);
+      dhcp_discover(netif);
+    }
+  } else if (dhcp->state == DHCP_REBOOTING) {
+    if (dhcp->tries < REBOOT_TRIES) {
+      dhcp_reboot(netif);
+    } else {
+      dhcp_discover(netif);
+    }
+  }
+}
+
+/**
+ * The renewal period has timed out.
+ *
+ * @param netif the netif under DHCP control
+ */
+static void
+dhcp_t1_timeout(struct netif *netif)
+{
+  struct dhcp *dhcp = netif->dhcp;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_t1_timeout()\n"));
+  if ((dhcp->state == DHCP_REQUESTING) || (dhcp->state == DHCP_BOUND) ||
+      (dhcp->state == DHCP_RENEWING)) {
+    /* just retry to renew - note that the rebind timer (t2) will
+     * eventually time-out if renew tries fail. */
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+                ("dhcp_t1_timeout(): must renew\n"));
+    /* This slightly different to RFC2131: DHCPREQUEST will be sent from state
+       DHCP_RENEWING, not DHCP_BOUND */
+    dhcp_renew(netif);
+  }
+}
+
+/**
+ * The rebind period has timed out.
+ *
+ * @param netif the netif under DHCP control
+ */
+static void
+dhcp_t2_timeout(struct netif *netif)
+{
+  struct dhcp *dhcp = netif->dhcp;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_t2_timeout()\n"));
+  if ((dhcp->state == DHCP_REQUESTING) || (dhcp->state == DHCP_BOUND) ||
+      (dhcp->state == DHCP_RENEWING)) {
+    /* just retry to rebind */
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+                ("dhcp_t2_timeout(): must rebind\n"));
+    /* This slightly different to RFC2131: DHCPREQUEST will be sent from state
+       DHCP_REBINDING, not DHCP_BOUND */
+    dhcp_rebind(netif);
+  }
+}
+
+/**
+ * Handle a DHCP ACK packet
+ *
+ * @param netif the netif under DHCP control
+ */
+static void
+dhcp_handle_ack(struct netif *netif)
+{
+  struct dhcp *dhcp = netif->dhcp;
+#if LWIP_DNS
+  u8_t n;
+#endif /* LWIP_DNS */
+
+  /* clear options we might not get from the ACK */
+  ip_addr_set_zero(&dhcp->offered_sn_mask);
+  ip_addr_set_zero(&dhcp->offered_gw_addr);
+#if LWIP_DHCP_BOOTP_FILE
+  ip_addr_set_zero(&dhcp->offered_si_addr);
+#endif /* LWIP_DHCP_BOOTP_FILE */
+
+  /* lease time given? */
+  if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_LEASE_TIME)) {
+    /* remember offered lease time */
+    dhcp->offered_t0_lease = dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_LEASE_TIME);
+  }
+  /* renewal period given? */
+  if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_T1)) {
+    /* remember given renewal period */
+    dhcp->offered_t1_renew = dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_T1);
+  } else {
+    /* calculate safe periods for renewal */
+    dhcp->offered_t1_renew = dhcp->offered_t0_lease / 2;
+  }
+
+  /* renewal period given? */
+  if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_T2)) {
+    /* remember given rebind period */
+    dhcp->offered_t2_rebind = dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_T2);
+  } else {
+    /* calculate safe periods for rebinding */
+    dhcp->offered_t2_rebind = dhcp->offered_t0_lease;
+  }
+
+  /* (y)our internet address */
+  ip_addr_copy(dhcp->offered_ip_addr, dhcp->msg_in->yiaddr);
+
+#if LWIP_DHCP_BOOTP_FILE
+  /* copy boot server address,
+     boot file name copied in dhcp_parse_reply if not overloaded */
+  ip_addr_copy(dhcp->offered_si_addr, dhcp->msg_in->siaddr);
+#endif /* LWIP_DHCP_BOOTP_FILE */
+
+  /* subnet mask given? */
+  if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_SUBNET_MASK)) {
+    /* remember given subnet mask */
+    ip4_addr_set_u32(&dhcp->offered_sn_mask, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_SUBNET_MASK)));
+    dhcp->subnet_mask_given = 1;
+  } else {
+    dhcp->subnet_mask_given = 0;
+  }
+
+  /* gateway router */
+  if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_ROUTER)) {
+    ip4_addr_set_u32(&dhcp->offered_gw_addr, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_ROUTER)));
+  }
+  
+#if LWIP_DNS
+  /* DNS servers */
+  n = 0;
+  while(dhcp_option_given(dhcp, DHCP_OPTION_IDX_DNS_SERVER + n) && (n < DNS_MAX_SERVERS)) {
+    ip_addr_t dns_addr;
+    ip4_addr_set_u32(&dns_addr, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_DNS_SERVER + n)));
+    dns_setserver(n, &dns_addr);
+    n++;
+  }
+#endif /* LWIP_DNS */
+}
+
+/** Set a statically allocated struct dhcp to work with.
+ * Using this prevents dhcp_start to allocate it using mem_malloc.
+ *
+ * @param netif the netif for which to set the struct dhcp
+ * @param dhcp (uninitialised) dhcp struct allocated by the application
+ */
+void
+dhcp_set_struct(struct netif *netif, struct dhcp *dhcp)
+{
+  LWIP_ASSERT("netif != NULL", netif != NULL);
+  LWIP_ASSERT("dhcp != NULL", dhcp != NULL);
+  LWIP_ASSERT("netif already has a struct dhcp set", netif->dhcp == NULL);
+
+  /* clear data structure */
+  memset(dhcp, 0, sizeof(struct dhcp));
+  /* dhcp_set_state(&dhcp, DHCP_OFF); */
+  netif->dhcp = dhcp;
+}
+
+/** Removes a struct dhcp from a netif.
+ *
+ * ATTENTION: Only use this when not using dhcp_set_struct() to allocate the
+ *            struct dhcp since the memory is passed back to the heap.
+ *
+ * @param netif the netif from which to remove the struct dhcp
+ */
+void dhcp_cleanup(struct netif *netif)
+{
+  LWIP_ASSERT("netif != NULL", netif != NULL);
+
+  if (netif->dhcp != NULL) {
+    mem_free(netif->dhcp);
+    netif->dhcp = NULL;
+  }
+}
+
+/**
+ * Start DHCP negotiation for a network interface.
+ *
+ * If no DHCP client instance was attached to this interface,
+ * a new client is created first. If a DHCP client instance
+ * was already present, it restarts negotiation.
+ *
+ * @param netif The lwIP network interface
+ * @return lwIP error code
+ * - ERR_OK - No error
+ * - ERR_MEM - Out of memory
+ */
+err_t
+dhcp_start(struct netif *netif)
+{
+  struct dhcp *dhcp;
+  err_t result = ERR_OK;
+
+  LWIP_ERROR("netif != NULL", (netif != NULL), return ERR_ARG;);
+  dhcp = netif->dhcp;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_start(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
+  /* Remove the flag that says this netif is handled by DHCP,
+     it is set when we succeeded starting. */
+  netif->flags &= ~NETIF_FLAG_DHCP;
+
+  /* check hwtype of the netif */
+  if ((netif->flags & NETIF_FLAG_ETHARP) == 0) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): No ETHARP netif\n"));
+    return ERR_ARG;
+  }
+
+  /* check MTU of the netif */
+  if (netif->mtu < DHCP_MAX_MSG_LEN_MIN_REQUIRED) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): Cannot use this netif with DHCP: MTU is too small\n"));
+    return ERR_MEM;
+  }
+
+  /* no DHCP client attached yet? */
+  if (dhcp == NULL) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): starting new DHCP client\n"));
+    dhcp = (struct dhcp *)mem_malloc(sizeof(struct dhcp));
+    if (dhcp == NULL) {
+      LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): could not allocate dhcp\n"));
+      return ERR_MEM;
+    }
+    /* store this dhcp client in the netif */
+    netif->dhcp = dhcp;
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): allocated dhcp"));
+  /* already has DHCP client attached */
+  } else {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_start(): restarting DHCP configuration\n"));
+    if (dhcp->pcb != NULL) {
+      udp_remove(dhcp->pcb);
+    }
+    LWIP_ASSERT("pbuf p_out wasn't freed", dhcp->p_out == NULL);
+    LWIP_ASSERT("reply wasn't freed", dhcp->msg_in == NULL );
+  }
+    
+  /* clear data structure */
+  memset(dhcp, 0, sizeof(struct dhcp));
+  /* dhcp_set_state(&dhcp, DHCP_OFF); */
+  /* allocate UDP PCB */
+  dhcp->pcb = udp_new();
+  if (dhcp->pcb == NULL) {
+    LWIP_DEBUGF(DHCP_DEBUG  | LWIP_DBG_TRACE, ("dhcp_start(): could not obtain pcb\n"));
+    return ERR_MEM;
+  }
+  dhcp->pcb->so_options |= SOF_BROADCAST;
+  /* set up local and remote port for the pcb */
+  udp_bind(dhcp->pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
+  udp_connect(dhcp->pcb, IP_ADDR_ANY, DHCP_SERVER_PORT);
+  /* set up the recv callback and argument */
+  udp_recv(dhcp->pcb, dhcp_recv, netif);
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): starting DHCP configuration\n"));
+  /* (re)start the DHCP negotiation */
+  result = dhcp_discover(netif);
+  if (result != ERR_OK) {
+    /* free resources allocated above */
+    dhcp_stop(netif);
+    return ERR_MEM;
+  }
+  /* Set the flag that says this netif is handled by DHCP. */
+  netif->flags |= NETIF_FLAG_DHCP;
+  return result;
+}
+
+/**
+ * Inform a DHCP server of our manual configuration.
+ *
+ * This informs DHCP servers of our fixed IP address configuration
+ * by sending an INFORM message. It does not involve DHCP address
+ * configuration, it is just here to be nice to the network.
+ *
+ * @param netif The lwIP network interface
+ */
+void
+dhcp_inform(struct netif *netif)
+{
+  struct dhcp dhcp;
+  err_t result = ERR_OK;
+  struct udp_pcb *pcb;
+
+  LWIP_ERROR("netif != NULL", (netif != NULL), return;);
+
+  memset(&dhcp, 0, sizeof(struct dhcp));
+  dhcp_set_state(&dhcp, DHCP_INFORM);
+
+  if ((netif->dhcp != NULL) && (netif->dhcp->pcb != NULL)) {
+    /* re-use existing pcb */
+    pcb = netif->dhcp->pcb;
+  } else {
+    pcb = udp_new();
+    if (pcb == NULL) {
+      LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_inform(): could not obtain pcb"));
+      return;
+    }
+    dhcp.pcb = pcb;
+    dhcp.pcb->so_options |= SOF_BROADCAST;
+    udp_bind(dhcp.pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_inform(): created new udp pcb\n"));
+  }
+  /* create and initialize the DHCP message header */
+  result = dhcp_create_msg(netif, &dhcp, DHCP_INFORM);
+  if (result == ERR_OK) {
+    dhcp_option(&dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
+    dhcp_option_short(&dhcp, DHCP_MAX_MSG_LEN(netif));
+
+    dhcp_option_trailer(&dhcp);
+
+    pbuf_realloc(dhcp.p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp.options_out_len);
+
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_inform: INFORMING\n"));
+    udp_sendto_if(pcb, dhcp.p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
+    dhcp_delete_msg(&dhcp);
+  } else {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_inform: could not allocate DHCP request\n"));
+  }
+
+  if (dhcp.pcb != NULL) {
+    /* otherwise, the existing pcb was used */
+    udp_remove(dhcp.pcb);
+  }
+}
+
+/** Handle a possible change in the network configuration.
+ *
+ * This enters the REBOOTING state to verify that the currently bound
+ * address is still valid.
+ */
+void
+dhcp_network_changed(struct netif *netif)
+{
+  struct dhcp *dhcp = netif->dhcp;
+  if (!dhcp)
+    return;
+  switch (dhcp->state) {
+  case DHCP_REBINDING:
+  case DHCP_RENEWING:
+  case DHCP_BOUND:
+  case DHCP_REBOOTING:
+    netif_set_down(netif);
+    dhcp->tries = 0;
+    dhcp_reboot(netif);
+    break;
+  case DHCP_OFF:
+    /* stay off */
+    break;
+  default:
+    dhcp->tries = 0;
+#if LWIP_DHCP_AUTOIP_COOP
+    if(dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_ON) {
+      autoip_stop(netif);
+      dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_OFF;
+    }
+#endif /* LWIP_DHCP_AUTOIP_COOP */
+    dhcp_discover(netif);
+    break;
+  }
+}
+
+#if DHCP_DOES_ARP_CHECK
+/**
+ * Match an ARP reply with the offered IP address.
+ *
+ * @param netif the network interface on which the reply was received
+ * @param addr The IP address we received a reply from
+ */
+void dhcp_arp_reply(struct netif *netif, ip_addr_t *addr)
+{
+  LWIP_ERROR("netif != NULL", (netif != NULL), return;);
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_arp_reply()\n"));
+  /* is a DHCP client doing an ARP check? */
+  if ((netif->dhcp != NULL) && (netif->dhcp->state == DHCP_CHECKING)) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_arp_reply(): CHECKING, arp reply for 0x%08"X32_F"\n",
+      ip4_addr_get_u32(addr)));
+    /* did a host respond with the address we
+       were offered by the DHCP server? */
+    if (ip_addr_cmp(addr, &netif->dhcp->offered_ip_addr)) {
+      /* we will not accept the offered address */
+      LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
+        ("dhcp_arp_reply(): arp reply matched with offered address, declining\n"));
+      dhcp_decline(netif);
+    }
+  }
+}
+
+/**
+ * Decline an offered lease.
+ *
+ * Tell the DHCP server we do not accept the offered address.
+ * One reason to decline the lease is when we find out the address
+ * is already in use by another host (through ARP).
+ *
+ * @param netif the netif under DHCP control
+ */
+static err_t
+dhcp_decline(struct netif *netif)
+{
+  struct dhcp *dhcp = netif->dhcp;
+  err_t result = ERR_OK;
+  u16_t msecs;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_decline()\n"));
+  dhcp_set_state(dhcp, DHCP_BACKING_OFF);
+  /* create and initialize the DHCP message header */
+  result = dhcp_create_msg(netif, dhcp, DHCP_DECLINE);
+  if (result == ERR_OK) {
+    dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
+    dhcp_option_long(dhcp, ntohl(ip4_addr_get_u32(&dhcp->offered_ip_addr)));
+
+    dhcp_option_trailer(dhcp);
+    /* resize pbuf to reflect true size of options */
+    pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
+
+    /* per section 4.4.4, broadcast DECLINE messages */
+    udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
+    dhcp_delete_msg(dhcp);
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_decline: BACKING OFF\n"));
+  } else {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
+      ("dhcp_decline: could not allocate DHCP request\n"));
+  }
+  dhcp->tries++;
+  msecs = 10*1000;
+  dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_decline(): set request timeout %"U16_F" msecs\n", msecs));
+  return result;
+}
+#endif /* DHCP_DOES_ARP_CHECK */
+
+
+/**
+ * Start the DHCP process, discover a DHCP server.
+ *
+ * @param netif the netif under DHCP control
+ */
+static err_t
+dhcp_discover(struct netif *netif)
+{
+  struct dhcp *dhcp = netif->dhcp;
+  err_t result = ERR_OK;
+  u16_t msecs;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover()\n"));
+  ip_addr_set_any(&dhcp->offered_ip_addr);
+  dhcp_set_state(dhcp, DHCP_SELECTING);
+  /* create and initialize the DHCP message header */
+  result = dhcp_create_msg(netif, dhcp, DHCP_DISCOVER);
+  if (result == ERR_OK) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: making request\n"));
+
+    dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
+    dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
+
+    dhcp_option(dhcp, DHCP_OPTION_PARAMETER_REQUEST_LIST, 4/*num options*/);
+    dhcp_option_byte(dhcp, DHCP_OPTION_SUBNET_MASK);
+    dhcp_option_byte(dhcp, DHCP_OPTION_ROUTER);
+    dhcp_option_byte(dhcp, DHCP_OPTION_BROADCAST);
+    dhcp_option_byte(dhcp, DHCP_OPTION_DNS_SERVER);
+
+    dhcp_option_trailer(dhcp);
+
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: realloc()ing\n"));
+    pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
+
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: sendto(DISCOVER, IP_ADDR_BROADCAST, DHCP_SERVER_PORT)\n"));
+    udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: deleting()ing\n"));
+    dhcp_delete_msg(dhcp);
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_discover: SELECTING\n"));
+  } else {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_discover: could not allocate DHCP request\n"));
+  }
+  dhcp->tries++;
+#if LWIP_DHCP_AUTOIP_COOP
+  if(dhcp->tries >= LWIP_DHCP_AUTOIP_COOP_TRIES && dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_OFF) {
+    dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_ON;
+    autoip_start(netif);
+  }
+#endif /* LWIP_DHCP_AUTOIP_COOP */
+  msecs = (dhcp->tries < 6 ? 1 << dhcp->tries : 60) * 1000;
+  dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_discover(): set request timeout %"U16_F" msecs\n", msecs));
+  return result;
+}
+
+
+/**
+ * Bind the interface to the offered IP address.
+ *
+ * @param netif network interface to bind to the offered address
+ */
+static void
+dhcp_bind(struct netif *netif)
+{
+  u32_t timeout;
+  struct dhcp *dhcp;
+  ip_addr_t sn_mask, gw_addr;
+  LWIP_ERROR("dhcp_bind: netif != NULL", (netif != NULL), return;);
+  dhcp = netif->dhcp;
+  LWIP_ERROR("dhcp_bind: dhcp != NULL", (dhcp != NULL), return;);
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_bind(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
+
+  /* temporary DHCP lease? */
+  if (dhcp->offered_t1_renew != 0xffffffffUL) {
+    /* set renewal period timer */
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_bind(): t1 renewal timer %"U32_F" secs\n", dhcp->offered_t1_renew));
+    timeout = (dhcp->offered_t1_renew + DHCP_COARSE_TIMER_SECS / 2) / DHCP_COARSE_TIMER_SECS;
+    if(timeout > 0xffff) {
+      timeout = 0xffff;
+    }
+    dhcp->t1_timeout = (u16_t)timeout;
+    if (dhcp->t1_timeout == 0) {
+      dhcp->t1_timeout = 1;
+    }
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_bind(): set request timeout %"U32_F" msecs\n", dhcp->offered_t1_renew*1000));
+  }
+  /* set renewal period timer */
+  if (dhcp->offered_t2_rebind != 0xffffffffUL) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_bind(): t2 rebind timer %"U32_F" secs\n", dhcp->offered_t2_rebind));
+    timeout = (dhcp->offered_t2_rebind + DHCP_COARSE_TIMER_SECS / 2) / DHCP_COARSE_TIMER_SECS;
+    if(timeout > 0xffff) {
+      timeout = 0xffff;
+    }
+    dhcp->t2_timeout = (u16_t)timeout;
+    if (dhcp->t2_timeout == 0) {
+      dhcp->t2_timeout = 1;
+    }
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_bind(): set request timeout %"U32_F" msecs\n", dhcp->offered_t2_rebind*1000));
+  }
+
+  if (dhcp->subnet_mask_given) {
+    /* copy offered network mask */
+    ip_addr_copy(sn_mask, dhcp->offered_sn_mask);
+  } else {
+    /* subnet mask not given, choose a safe subnet mask given the network class */
+    u8_t first_octet = ip4_addr1(&dhcp->offered_ip_addr);
+    if (first_octet <= 127) {
+      ip4_addr_set_u32(&sn_mask, PP_HTONL(0xff000000UL));
+    } else if (first_octet >= 192) {
+      ip4_addr_set_u32(&sn_mask, PP_HTONL(0xffffff00UL));
+    } else {
+      ip4_addr_set_u32(&sn_mask, PP_HTONL(0xffff0000UL));
+    }
+  }
+
+  ip_addr_copy(gw_addr, dhcp->offered_gw_addr);
+  /* gateway address not given? */
+  if (ip_addr_isany(&gw_addr)) {
+    /* copy network address */
+    ip_addr_get_network(&gw_addr, &dhcp->offered_ip_addr, &sn_mask);
+    /* use first host address on network as gateway */
+    ip4_addr_set_u32(&gw_addr, ip4_addr_get_u32(&gw_addr) | PP_HTONL(0x00000001UL));
+  }
+
+#if LWIP_DHCP_AUTOIP_COOP
+  if(dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_ON) {
+    autoip_stop(netif);
+    dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_OFF;
+  }
+#endif /* LWIP_DHCP_AUTOIP_COOP */
+
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_bind(): IP: 0x%08"X32_F"\n",
+    ip4_addr_get_u32(&dhcp->offered_ip_addr)));
+  netif_set_ipaddr(netif, &dhcp->offered_ip_addr);
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_bind(): SN: 0x%08"X32_F"\n",
+    ip4_addr_get_u32(&sn_mask)));
+  netif_set_netmask(netif, &sn_mask);
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_bind(): GW: 0x%08"X32_F"\n",
+    ip4_addr_get_u32(&gw_addr)));
+  netif_set_gw(netif, &gw_addr);
+  /* bring the interface up */
+  netif_set_up(netif);
+  /* netif is now bound to DHCP leased address */
+  dhcp_set_state(dhcp, DHCP_BOUND);
+}
+
+/**
+ * Renew an existing DHCP lease at the involved DHCP server.
+ *
+ * @param netif network interface which must renew its lease
+ */
+err_t
+dhcp_renew(struct netif *netif)
+{
+  struct dhcp *dhcp = netif->dhcp;
+  err_t result;
+  u16_t msecs;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_renew()\n"));
+  dhcp_set_state(dhcp, DHCP_RENEWING);
+
+  /* create and initialize the DHCP message header */
+  result = dhcp_create_msg(netif, dhcp, DHCP_REQUEST);
+  if (result == ERR_OK) {
+    dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
+    dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
+
+#if LWIP_NETIF_HOSTNAME
+    if (netif->hostname != NULL) {
+      const char *p = (const char*)netif->hostname;
+      u8_t namelen = (u8_t)strlen(p);
+      if (namelen > 0) {
+        LWIP_ASSERT("DHCP: hostname is too long!", namelen < 255);
+        dhcp_option(dhcp, DHCP_OPTION_HOSTNAME, namelen);
+        while (*p) {
+          dhcp_option_byte(dhcp, *p++);
+        }
+      }
+    }
+#endif /* LWIP_NETIF_HOSTNAME */
+
+#if 0
+    dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
+    dhcp_option_long(dhcp, ntohl(dhcp->offered_ip_addr.addr));
+#endif
+
+#if 0
+    dhcp_option(dhcp, DHCP_OPTION_SERVER_ID, 4);
+    dhcp_option_long(dhcp, ntohl(dhcp->server_ip_addr.addr));
+#endif
+    /* append DHCP message trailer */
+    dhcp_option_trailer(dhcp);
+
+    pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
+
+    udp_sendto_if(dhcp->pcb, dhcp->p_out, &dhcp->server_ip_addr, DHCP_SERVER_PORT, netif);
+    dhcp_delete_msg(dhcp);
+
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_renew: RENEWING\n"));
+  } else {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_renew: could not allocate DHCP request\n"));
+  }
+  dhcp->tries++;
+  /* back-off on retries, but to a maximum of 20 seconds */
+  msecs = dhcp->tries < 10 ? dhcp->tries * 2000 : 20 * 1000;
+  dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_renew(): set request timeout %"U16_F" msecs\n", msecs));
+  return result;
+}
+
+/**
+ * Rebind with a DHCP server for an existing DHCP lease.
+ *
+ * @param netif network interface which must rebind with a DHCP server
+ */
+static err_t
+dhcp_rebind(struct netif *netif)
+{
+  struct dhcp *dhcp = netif->dhcp;
+  err_t result;
+  u16_t msecs;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_rebind()\n"));
+  dhcp_set_state(dhcp, DHCP_REBINDING);
+
+  /* create and initialize the DHCP message header */
+  result = dhcp_create_msg(netif, dhcp, DHCP_REQUEST);
+  if (result == ERR_OK) {
+    dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
+    dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
+
+#if LWIP_NETIF_HOSTNAME
+    if (netif->hostname != NULL) {
+      const char *p = (const char*)netif->hostname;
+      u8_t namelen = (u8_t)strlen(p);
+      if (namelen > 0) {
+        LWIP_ASSERT("DHCP: hostname is too long!", namelen < 255);
+        dhcp_option(dhcp, DHCP_OPTION_HOSTNAME, namelen);
+        while (*p) {
+          dhcp_option_byte(dhcp, *p++);
+        }
+      }
+    }
+#endif /* LWIP_NETIF_HOSTNAME */
+
+#if 0
+    dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
+    dhcp_option_long(dhcp, ntohl(dhcp->offered_ip_addr.addr));
+
+    dhcp_option(dhcp, DHCP_OPTION_SERVER_ID, 4);
+    dhcp_option_long(dhcp, ntohl(dhcp->server_ip_addr.addr));
+#endif
+
+    dhcp_option_trailer(dhcp);
+
+    pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
+
+    /* broadcast to server */
+    udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
+    dhcp_delete_msg(dhcp);
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_rebind: REBINDING\n"));
+  } else {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_rebind: could not allocate DHCP request\n"));
+  }
+  dhcp->tries++;
+  msecs = dhcp->tries < 10 ? dhcp->tries * 1000 : 10 * 1000;
+  dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_rebind(): set request timeout %"U16_F" msecs\n", msecs));
+  return result;
+}
+
+/**
+ * Enter REBOOTING state to verify an existing lease
+ *
+ * @param netif network interface which must reboot
+ */
+static err_t
+dhcp_reboot(struct netif *netif)
+{
+  struct dhcp *dhcp = netif->dhcp;
+  err_t result;
+  u16_t msecs;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_reboot()\n"));
+  dhcp_set_state(dhcp, DHCP_REBOOTING);
+
+  /* create and initialize the DHCP message header */
+  result = dhcp_create_msg(netif, dhcp, DHCP_REQUEST);
+  if (result == ERR_OK) {
+    dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
+    dhcp_option_short(dhcp, 576);
+
+    dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
+    dhcp_option_long(dhcp, ntohl(ip4_addr_get_u32(&dhcp->offered_ip_addr)));
+
+    dhcp_option_trailer(dhcp);
+
+    pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
+
+    /* broadcast to server */
+    udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
+    dhcp_delete_msg(dhcp);
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_reboot: REBOOTING\n"));
+  } else {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_reboot: could not allocate DHCP request\n"));
+  }
+  dhcp->tries++;
+  msecs = dhcp->tries < 10 ? dhcp->tries * 1000 : 10 * 1000;
+  dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_reboot(): set request timeout %"U16_F" msecs\n", msecs));
+  return result;
+}
+
+
+/**
+ * Release a DHCP lease.
+ *
+ * @param netif network interface which must release its lease
+ */
+err_t
+dhcp_release(struct netif *netif)
+{
+  struct dhcp *dhcp = netif->dhcp;
+  err_t result;
+  u16_t msecs;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_release()\n"));
+
+  /* idle DHCP client */
+  dhcp_set_state(dhcp, DHCP_OFF);
+  /* clean old DHCP offer */
+  ip_addr_set_zero(&dhcp->server_ip_addr);
+  ip_addr_set_zero(&dhcp->offered_ip_addr);
+  ip_addr_set_zero(&dhcp->offered_sn_mask);
+  ip_addr_set_zero(&dhcp->offered_gw_addr);
+#if LWIP_DHCP_BOOTP_FILE
+  ip_addr_set_zero(&dhcp->offered_si_addr);
+#endif /* LWIP_DHCP_BOOTP_FILE */
+  dhcp->offered_t0_lease = dhcp->offered_t1_renew = dhcp->offered_t2_rebind = 0;
+  
+  /* create and initialize the DHCP message header */
+  result = dhcp_create_msg(netif, dhcp, DHCP_RELEASE);
+  if (result == ERR_OK) {
+    dhcp_option_trailer(dhcp);
+
+    pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
+
+    udp_sendto_if(dhcp->pcb, dhcp->p_out, &dhcp->server_ip_addr, DHCP_SERVER_PORT, netif);
+    dhcp_delete_msg(dhcp);
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_release: RELEASED, DHCP_OFF\n"));
+  } else {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_release: could not allocate DHCP request\n"));
+  }
+  dhcp->tries++;
+  msecs = dhcp->tries < 10 ? dhcp->tries * 1000 : 10 * 1000;
+  dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_release(): set request timeout %"U16_F" msecs\n", msecs));
+  /* bring the interface down */
+  netif_set_down(netif);
+  /* remove IP address from interface */
+  netif_set_ipaddr(netif, IP_ADDR_ANY);
+  netif_set_gw(netif, IP_ADDR_ANY);
+  netif_set_netmask(netif, IP_ADDR_ANY);
+  
+  return result;
+}
+
+/**
+ * Remove the DHCP client from the interface.
+ *
+ * @param netif The network interface to stop DHCP on
+ */
+void
+dhcp_stop(struct netif *netif)
+{
+  struct dhcp *dhcp;
+  LWIP_ERROR("dhcp_stop: netif != NULL", (netif != NULL), return;);
+  dhcp = netif->dhcp;
+  /* Remove the flag that says this netif is handled by DHCP. */
+  netif->flags &= ~NETIF_FLAG_DHCP;
+
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_stop()\n"));
+  /* netif is DHCP configured? */
+  if (dhcp != NULL) {
+#if LWIP_DHCP_AUTOIP_COOP
+    if(dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_ON) {
+      autoip_stop(netif);
+      dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_OFF;
+    }
+#endif /* LWIP_DHCP_AUTOIP_COOP */
+
+    if (dhcp->pcb != NULL) {
+      udp_remove(dhcp->pcb);
+      dhcp->pcb = NULL;
+    }
+    LWIP_ASSERT("reply wasn't freed", dhcp->msg_in == NULL);
+    dhcp_set_state(dhcp, DHCP_OFF);
+  }
+}
+
+/*
+ * Set the DHCP state of a DHCP client.
+ *
+ * If the state changed, reset the number of tries.
+ */
+static void
+dhcp_set_state(struct dhcp *dhcp, u8_t new_state)
+{
+  if (new_state != dhcp->state) {
+    dhcp->state = new_state;
+    dhcp->tries = 0;
+    dhcp->request_timeout = 0;
+  }
+}
+
+/*
+ * Concatenate an option type and length field to the outgoing
+ * DHCP message.
+ *
+ */
+static void
+dhcp_option(struct dhcp *dhcp, u8_t option_type, u8_t option_len)
+{
+  LWIP_ASSERT("dhcp_option: dhcp->options_out_len + 2 + option_len <= DHCP_OPTIONS_LEN", dhcp->options_out_len + 2U + option_len <= DHCP_OPTIONS_LEN);
+  dhcp->msg_out->options[dhcp->options_out_len++] = option_type;
+  dhcp->msg_out->options[dhcp->options_out_len++] = option_len;
+}
+/*
+ * Concatenate a single byte to the outgoing DHCP message.
+ *
+ */
+static void
+dhcp_option_byte(struct dhcp *dhcp, u8_t value)
+{
+  LWIP_ASSERT("dhcp_option_byte: dhcp->options_out_len < DHCP_OPTIONS_LEN", dhcp->options_out_len < DHCP_OPTIONS_LEN);
+  dhcp->msg_out->options[dhcp->options_out_len++] = value;
+}
+
+static void
+dhcp_option_short(struct dhcp *dhcp, u16_t value)
+{
+  LWIP_ASSERT("dhcp_option_short: dhcp->options_out_len + 2 <= DHCP_OPTIONS_LEN", dhcp->options_out_len + 2U <= DHCP_OPTIONS_LEN);
+  dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0xff00U) >> 8);
+  dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t) (value & 0x00ffU);
+}
+
+static void
+dhcp_option_long(struct dhcp *dhcp, u32_t value)
+{
+  LWIP_ASSERT("dhcp_option_long: dhcp->options_out_len + 4 <= DHCP_OPTIONS_LEN", dhcp->options_out_len + 4U <= DHCP_OPTIONS_LEN);
+  dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0xff000000UL) >> 24);
+  dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0x00ff0000UL) >> 16);
+  dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0x0000ff00UL) >> 8);
+  dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0x000000ffUL));
+}
+
+/**
+ * Extract the DHCP message and the DHCP options.
+ *
+ * Extract the DHCP message and the DHCP options, each into a contiguous
+ * piece of memory. As a DHCP message is variable sized by its options,
+ * and also allows overriding some fields for options, the easy approach
+ * is to first unfold the options into a conitguous piece of memory, and
+ * use that further on.
+ *
+ */
+static err_t
+dhcp_parse_reply(struct dhcp *dhcp, struct pbuf *p)
+{
+  u8_t *options;
+  u16_t offset;
+  u16_t offset_max;
+  u16_t options_idx;
+  u16_t options_idx_max;
+  struct pbuf *q;
+  int parse_file_as_options = 0;
+  int parse_sname_as_options = 0;
+
+  /* clear received options */
+  dhcp_clear_all_options(dhcp);
+  /* check that beginning of dhcp_msg (up to and including chaddr) is in first pbuf */
+  if (p->len < DHCP_SNAME_OFS) {
+    return ERR_BUF;
+  }
+  dhcp->msg_in = (struct dhcp_msg *)p->payload;
+#if LWIP_DHCP_BOOTP_FILE
+  /* clear boot file name */
+  dhcp->boot_file_name[0] = 0;
+#endif /* LWIP_DHCP_BOOTP_FILE */
+
+  /* parse options */
+
+  /* start with options field */
+  options_idx = DHCP_OPTIONS_OFS;
+  /* parse options to the end of the received packet */
+  options_idx_max = p->tot_len;
+again:
+  q = p;
+  while((q != NULL) && (options_idx >= q->len)) {
+    options_idx -= q->len;
+    options_idx_max -= q->len;
+    q = q->next;
+  }
+  if (q == NULL) {
+    return ERR_BUF;
+  }
+  offset = options_idx;
+  offset_max = options_idx_max;
+  options = (u8_t*)q->payload;
+  /* at least 1 byte to read and no end marker, then at least 3 bytes to read? */
+  while((q != NULL) && (options[offset] != DHCP_OPTION_END) && (offset < offset_max)) {
+    u8_t op = options[offset];
+    u8_t len;
+    u8_t decode_len = 0;
+    int decode_idx = -1;
+    u16_t val_offset = offset + 2;
+    /* len byte might be in the next pbuf */
+    if (offset + 1 < q->len) {
+      len = options[offset + 1];
+    } else {
+      len = (q->next != NULL ? ((u8_t*)q->next->payload)[0] : 0);
+    }
+    /* LWIP_DEBUGF(DHCP_DEBUG, ("msg_offset=%"U16_F", q->len=%"U16_F, msg_offset, q->len)); */
+    decode_len = len;
+    switch(op) {
+      /* case(DHCP_OPTION_END): handled above */
+      case(DHCP_OPTION_PAD):
+        /* special option: no len encoded */
+        decode_len = len = 0;
+        /* will be increased below */
+        offset--;
+        break;
+      case(DHCP_OPTION_SUBNET_MASK):
+        LWIP_ASSERT("len == 4", len == 4);
+        decode_idx = DHCP_OPTION_IDX_SUBNET_MASK;
+        break;
+      case(DHCP_OPTION_ROUTER):
+        decode_len = 4; /* only copy the first given router */
+        LWIP_ASSERT("len >= decode_len", len >= decode_len);
+        decode_idx = DHCP_OPTION_IDX_ROUTER;
+        break;
+      case(DHCP_OPTION_DNS_SERVER):
+        /* special case: there might be more than one server */
+        LWIP_ASSERT("len % 4 == 0", len % 4 == 0);
+        /* limit number of DNS servers */
+        decode_len = LWIP_MIN(len, 4 * DNS_MAX_SERVERS);
+        LWIP_ASSERT("len >= decode_len", len >= decode_len);
+        decode_idx = DHCP_OPTION_IDX_DNS_SERVER;
+        break;
+      case(DHCP_OPTION_LEASE_TIME):
+        LWIP_ASSERT("len == 4", len == 4);
+        decode_idx = DHCP_OPTION_IDX_LEASE_TIME;
+        break;
+      case(DHCP_OPTION_OVERLOAD):
+        LWIP_ASSERT("len == 1", len == 1);
+        decode_idx = DHCP_OPTION_IDX_OVERLOAD;
+        break;
+      case(DHCP_OPTION_MESSAGE_TYPE):
+        LWIP_ASSERT("len == 1", len == 1);
+        decode_idx = DHCP_OPTION_IDX_MSG_TYPE;
+        break;
+      case(DHCP_OPTION_SERVER_ID):
+        LWIP_ASSERT("len == 4", len == 4);
+        decode_idx = DHCP_OPTION_IDX_SERVER_ID;
+        break;
+      case(DHCP_OPTION_T1):
+        LWIP_ASSERT("len == 4", len == 4);
+        decode_idx = DHCP_OPTION_IDX_T1;
+        break;
+      case(DHCP_OPTION_T2):
+        LWIP_ASSERT("len == 4", len == 4);
+        decode_idx = DHCP_OPTION_IDX_T2;
+        break;
+      default:
+        decode_len = 0;
+        LWIP_DEBUGF(DHCP_DEBUG, ("skipping option %"U16_F" in options\n", op));
+        break;
+    }
+    offset += len + 2;
+    if (decode_len > 0) {
+      u32_t value = 0;
+      u16_t copy_len;
+decode_next:
+      LWIP_ASSERT("check decode_idx", decode_idx >= 0 && decode_idx < DHCP_OPTION_IDX_MAX);
+      LWIP_ASSERT("option already decoded", !dhcp_option_given(dhcp, decode_idx));
+      copy_len = LWIP_MIN(decode_len, 4);
+      pbuf_copy_partial(q, &value, copy_len, val_offset);
+      if (decode_len > 4) {
+        /* decode more than one u32_t */
+        LWIP_ASSERT("decode_len % 4 == 0", decode_len % 4 == 0);
+        dhcp_got_option(dhcp, decode_idx);
+        dhcp_set_option_value(dhcp, decode_idx, htonl(value));
+        decode_len -= 4;
+        val_offset += 4;
+        decode_idx++;
+        goto decode_next;
+      } else if (decode_len == 4) {
+        value = ntohl(value);
+      } else {
+        LWIP_ASSERT("invalid decode_len", decode_len == 1);
+        value = ((u8_t*)&value)[0];
+      }
+      dhcp_got_option(dhcp, decode_idx);
+      dhcp_set_option_value(dhcp, decode_idx, value);
+    }
+    if (offset >= q->len) {
+      offset -= q->len;
+      offset_max -= q->len;
+      q = q->next;
+      options = (u8_t*)q->payload;
+    }
+  }
+  /* is this an overloaded message? */
+  if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_OVERLOAD)) {
+    u32_t overload = dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_OVERLOAD);
+    dhcp_clear_option(dhcp, DHCP_OPTION_IDX_OVERLOAD);
+    if (overload == DHCP_OVERLOAD_FILE) {
+      parse_file_as_options = 1;
+      LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("overloaded file field\n"));
+    } else if (overload == DHCP_OVERLOAD_SNAME) {
+      parse_sname_as_options = 1;
+      LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("overloaded sname field\n"));
+    } else if (overload == DHCP_OVERLOAD_SNAME_FILE) {
+      parse_sname_as_options = 1;
+      parse_file_as_options = 1;
+      LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("overloaded sname and file field\n"));
+    } else {
+      LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("invalid overload option: %d\n", (int)overload));
+    }
+#if LWIP_DHCP_BOOTP_FILE
+    if (!parse_file_as_options) {
+      /* only do this for ACK messages */
+      if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_MSG_TYPE) &&
+        (dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_MSG_TYPE) == DHCP_ACK))
+      /* copy bootp file name, don't care for sname (server hostname) */
+      pbuf_copy_partial(p, dhcp->boot_file_name, DHCP_FILE_LEN-1, DHCP_FILE_OFS);
+      /* make sure the string is really NULL-terminated */
+      dhcp->boot_file_name[DHCP_FILE_LEN-1] = 0;
+    }
+#endif /* LWIP_DHCP_BOOTP_FILE */
+  }
+  if (parse_file_as_options) {
+    /* if both are overloaded, parse file first and then sname (RFC 2131 ch. 4.1) */
+    parse_file_as_options = 0;
+    options_idx = DHCP_FILE_OFS;
+    options_idx_max = DHCP_FILE_OFS + DHCP_FILE_LEN;
+    goto again;
+  } else if (parse_sname_as_options) {
+    parse_sname_as_options = 0;
+    options_idx = DHCP_SNAME_OFS;
+    options_idx_max = DHCP_SNAME_OFS + DHCP_SNAME_LEN;
+    goto again;
+  }
+  return ERR_OK;
+}
+
+/**
+ * If an incoming DHCP message is in response to us, then trigger the state machine
+ */
+static void
+dhcp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port)
+{
+  struct netif *netif = (struct netif *)arg;
+  struct dhcp *dhcp = netif->dhcp;
+  struct dhcp_msg *reply_msg = (struct dhcp_msg *)p->payload;
+  u8_t msg_type;
+  u8_t i;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_recv(pbuf = %p) from DHCP server %"U16_F".%"U16_F".%"U16_F".%"U16_F" port %"U16_F"\n", (void*)p,
+    ip4_addr1_16(addr), ip4_addr2_16(addr), ip4_addr3_16(addr), ip4_addr4_16(addr), port));
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("pbuf->len = %"U16_F"\n", p->len));
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("pbuf->tot_len = %"U16_F"\n", p->tot_len));
+  /* prevent warnings about unused arguments */
+  LWIP_UNUSED_ARG(pcb);
+  LWIP_UNUSED_ARG(addr);
+  LWIP_UNUSED_ARG(port);
+
+  LWIP_ASSERT("reply wasn't freed", dhcp->msg_in == NULL);
+
+  if (p->len < DHCP_MIN_REPLY_LEN) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("DHCP reply message or pbuf too short\n"));
+    goto free_pbuf_and_return;
+  }
+
+  if (reply_msg->op != DHCP_BOOTREPLY) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("not a DHCP reply message, but type %"U16_F"\n", (u16_t)reply_msg->op));
+    goto free_pbuf_and_return;
+  }
+  /* iterate through hardware address and match against DHCP message */
+  for (i = 0; i < netif->hwaddr_len; i++) {
+    if (netif->hwaddr[i] != reply_msg->chaddr[i]) {
+      LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING,
+        ("netif->hwaddr[%"U16_F"]==%02"X16_F" != reply_msg->chaddr[%"U16_F"]==%02"X16_F"\n",
+        (u16_t)i, (u16_t)netif->hwaddr[i], (u16_t)i, (u16_t)reply_msg->chaddr[i]));
+      goto free_pbuf_and_return;
+    }
+  }
+  /* match transaction ID against what we expected */
+  if (ntohl(reply_msg->xid) != dhcp->xid) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING,
+      ("transaction id mismatch reply_msg->xid(%"X32_F")!=dhcp->xid(%"X32_F")\n",ntohl(reply_msg->xid),dhcp->xid));
+    goto free_pbuf_and_return;
+  }
+  /* option fields could be unfold? */
+  if (dhcp_parse_reply(dhcp, p) != ERR_OK) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
+      ("problem unfolding DHCP message - too short on memory?\n"));
+    goto free_pbuf_and_return;
+  }
+
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("searching DHCP_OPTION_MESSAGE_TYPE\n"));
+  /* obtain pointer to DHCP message type */
+  if (!dhcp_option_given(dhcp, DHCP_OPTION_IDX_MSG_TYPE)) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("DHCP_OPTION_MESSAGE_TYPE option not found\n"));
+    goto free_pbuf_and_return;
+  }
+
+  /* read DHCP message type */
+  msg_type = (u8_t)dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_MSG_TYPE);
+  /* message type is DHCP ACK? */
+  if (msg_type == DHCP_ACK) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("DHCP_ACK received\n"));
+    /* in requesting state? */
+    if (dhcp->state == DHCP_REQUESTING) {
+      dhcp_handle_ack(netif);
+#if DHCP_DOES_ARP_CHECK
+      /* check if the acknowledged lease address is already in use */
+      dhcp_check(netif);
+#else
+      /* bind interface to the acknowledged lease address */
+      dhcp_bind(netif);
+#endif
+    }
+    /* already bound to the given lease address? */
+    else if ((dhcp->state == DHCP_REBOOTING) || (dhcp->state == DHCP_REBINDING) || (dhcp->state == DHCP_RENEWING)) {
+      dhcp_bind(netif);
+    }
+  }
+  /* received a DHCP_NAK in appropriate state? */
+  else if ((msg_type == DHCP_NAK) &&
+    ((dhcp->state == DHCP_REBOOTING) || (dhcp->state == DHCP_REQUESTING) ||
+     (dhcp->state == DHCP_REBINDING) || (dhcp->state == DHCP_RENEWING  ))) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("DHCP_NAK received\n"));
+    dhcp_handle_nak(netif);
+  }
+  /* received a DHCP_OFFER in DHCP_SELECTING state? */
+  else if ((msg_type == DHCP_OFFER) && (dhcp->state == DHCP_SELECTING)) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("DHCP_OFFER received in DHCP_SELECTING state\n"));
+    dhcp->request_timeout = 0;
+    /* remember offered lease */
+    dhcp_handle_offer(netif);
+  }
+free_pbuf_and_return:
+  dhcp->msg_in = NULL;
+  pbuf_free(p);
+}
+
+/**
+ * Create a DHCP request, fill in common headers
+ *
+ * @param netif the netif under DHCP control
+ * @param dhcp dhcp control struct
+ * @param message_type message type of the request
+ */
+static err_t
+dhcp_create_msg(struct netif *netif, struct dhcp *dhcp, u8_t message_type)
+{
+  u16_t i;
+#ifndef DHCP_GLOBAL_XID
+  /** default global transaction identifier starting value (easy to match
+   *  with a packet analyser). We simply increment for each new request.
+   *  Predefine DHCP_GLOBAL_XID to a better value or a function call to generate one
+   *  at runtime, any supporting function prototypes can be defined in DHCP_GLOBAL_XID_HEADER */
+  static u32_t xid = 0xABCD0000;
+#else
+  static u32_t xid;
+  static u8_t xid_initialised = 0;
+  if (!xid_initialised) {
+    xid = DHCP_GLOBAL_XID;
+    xid_initialised = !xid_initialised;
+  }
+#endif
+  LWIP_ERROR("dhcp_create_msg: netif != NULL", (netif != NULL), return ERR_ARG;);
+  LWIP_ERROR("dhcp_create_msg: dhcp != NULL", (dhcp != NULL), return ERR_VAL;);
+  LWIP_ASSERT("dhcp_create_msg: dhcp->p_out == NULL", dhcp->p_out == NULL);
+  LWIP_ASSERT("dhcp_create_msg: dhcp->msg_out == NULL", dhcp->msg_out == NULL);
+  dhcp->p_out = pbuf_alloc(PBUF_TRANSPORT, sizeof(struct dhcp_msg), PBUF_RAM);
+  if (dhcp->p_out == NULL) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
+      ("dhcp_create_msg(): could not allocate pbuf\n"));
+    return ERR_MEM;
+  }
+  LWIP_ASSERT("dhcp_create_msg: check that first pbuf can hold struct dhcp_msg",
+           (dhcp->p_out->len >= sizeof(struct dhcp_msg)));
+
+  /* reuse transaction identifier in retransmissions */
+  if (dhcp->tries == 0) {
+      xid++;
+  }
+  dhcp->xid = xid;
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE,
+              ("transaction id xid(%"X32_F")\n", xid));
+
+  dhcp->msg_out = (struct dhcp_msg *)dhcp->p_out->payload;
+
+  dhcp->msg_out->op = DHCP_BOOTREQUEST;
+  /* TODO: make link layer independent */
+  dhcp->msg_out->htype = DHCP_HTYPE_ETH;
+  dhcp->msg_out->hlen = netif->hwaddr_len;
+  dhcp->msg_out->hops = 0;
+  dhcp->msg_out->xid = htonl(dhcp->xid);
+  dhcp->msg_out->secs = 0;
+  /* we don't need the broadcast flag since we can receive unicast traffic
+     before being fully configured! */
+  dhcp->msg_out->flags = 0;
+  ip_addr_set_zero(&dhcp->msg_out->ciaddr);
+  /* set ciaddr to netif->ip_addr based on message_type and state */
+  if ((message_type == DHCP_INFORM) || (message_type == DHCP_DECLINE) ||
+      ((message_type == DHCP_REQUEST) && /* DHCP_BOUND not used for sending! */
+       ((dhcp->state==DHCP_RENEWING) || dhcp->state==DHCP_REBINDING))) {
+    ip_addr_copy(dhcp->msg_out->ciaddr, netif->ip_addr);
+  }
+  ip_addr_set_zero(&dhcp->msg_out->yiaddr);
+  ip_addr_set_zero(&dhcp->msg_out->siaddr);
+  ip_addr_set_zero(&dhcp->msg_out->giaddr);
+  for (i = 0; i < DHCP_CHADDR_LEN; i++) {
+    /* copy netif hardware address, pad with zeroes */
+    dhcp->msg_out->chaddr[i] = (i < netif->hwaddr_len) ? netif->hwaddr[i] : 0/* pad byte*/;
+  }
+  for (i = 0; i < DHCP_SNAME_LEN; i++) {
+    dhcp->msg_out->sname[i] = 0;
+  }
+  for (i = 0; i < DHCP_FILE_LEN; i++) {
+    dhcp->msg_out->file[i] = 0;
+  }
+  dhcp->msg_out->cookie = PP_HTONL(DHCP_MAGIC_COOKIE);
+  dhcp->options_out_len = 0;
+  /* fill options field with an incrementing array (for debugging purposes) */
+  for (i = 0; i < DHCP_OPTIONS_LEN; i++) {
+    dhcp->msg_out->options[i] = (u8_t)i; /* for debugging only, no matter if truncated */
+  }
+  /* Add option MESSAGE_TYPE */
+  dhcp_option(dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
+  dhcp_option_byte(dhcp, message_type);
+  return ERR_OK;
+}
+
+/**
+ * Free previously allocated memory used to send a DHCP request.
+ *
+ * @param dhcp the dhcp struct to free the request from
+ */
+static void
+dhcp_delete_msg(struct dhcp *dhcp)
+{
+  LWIP_ERROR("dhcp_delete_msg: dhcp != NULL", (dhcp != NULL), return;);
+  LWIP_ASSERT("dhcp_delete_msg: dhcp->p_out != NULL", dhcp->p_out != NULL);
+  LWIP_ASSERT("dhcp_delete_msg: dhcp->msg_out != NULL", dhcp->msg_out != NULL);
+  if (dhcp->p_out != NULL) {
+    pbuf_free(dhcp->p_out);
+  }
+  dhcp->p_out = NULL;
+  dhcp->msg_out = NULL;
+}
+
+/**
+ * Add a DHCP message trailer
+ *
+ * Adds the END option to the DHCP message, and if
+ * necessary, up to three padding bytes.
+ *
+ * @param dhcp DHCP state structure
+ */
+static void
+dhcp_option_trailer(struct dhcp *dhcp)
+{
+  LWIP_ERROR("dhcp_option_trailer: dhcp != NULL", (dhcp != NULL), return;);
+  LWIP_ASSERT("dhcp_option_trailer: dhcp->msg_out != NULL\n", dhcp->msg_out != NULL);
+  LWIP_ASSERT("dhcp_option_trailer: dhcp->options_out_len < DHCP_OPTIONS_LEN\n", dhcp->options_out_len < DHCP_OPTIONS_LEN);
+  dhcp->msg_out->options[dhcp->options_out_len++] = DHCP_OPTION_END;
+  /* packet is too small, or not 4 byte aligned? */
+  while ((dhcp->options_out_len < DHCP_MIN_OPTIONS_LEN) || (dhcp->options_out_len & 3)) {
+    /* LWIP_DEBUGF(DHCP_DEBUG,("dhcp_option_trailer:dhcp->options_out_len=%"U16_F", DHCP_OPTIONS_LEN=%"U16_F, dhcp->options_out_len, DHCP_OPTIONS_LEN)); */
+    LWIP_ASSERT("dhcp_option_trailer: dhcp->options_out_len < DHCP_OPTIONS_LEN\n", dhcp->options_out_len < DHCP_OPTIONS_LEN);
+    /* add a fill/padding byte */
+    dhcp->msg_out->options[dhcp->options_out_len++] = 0;
+  }
+}
+
+#endif /* LWIP_DHCP */
diff --git a/core/lwip/src/core/dns.c b/core/lwip/src/core/dns.c
new file mode 100644
index 00000000..ca807c14
--- /dev/null
+++ b/core/lwip/src/core/dns.c
@@ -0,0 +1,975 @@
+/**
+ * @file
+ * DNS - host name to IP address resolver.
+ *
+ */
+
+/**
+
+ * This file implements a DNS host name to IP address resolver.
+
+ * Port to lwIP from uIP
+ * by Jim Pettinato April 2007
+
+ * uIP version Copyright (c) 2002-2003, Adam Dunkels.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote
+ *    products derived from this software without specific prior
+ *    written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
+ * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
+ * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *
+ * DNS.C
+ *
+ * The lwIP DNS resolver functions are used to lookup a host name and
+ * map it to a numerical IP address. It maintains a list of resolved
+ * hostnames that can be queried with the dns_lookup() function.
+ * New hostnames can be resolved using the dns_query() function.
+ *
+ * The lwIP version of the resolver also adds a non-blocking version of
+ * gethostbyname() that will work with a raw API application. This function
+ * checks for an IP address string first and converts it if it is valid.
+ * gethostbyname() then does a dns_lookup() to see if the name is 
+ * already in the table. If so, the IP is returned. If not, a query is 
+ * issued and the function returns with a ERR_INPROGRESS status. The app
+ * using the dns client must then go into a waiting state.
+ *
+ * Once a hostname has been resolved (or found to be non-existent),
+ * the resolver code calls a specified callback function (which 
+ * must be implemented by the module that uses the resolver).
+ */
+
+/*-----------------------------------------------------------------------------
+ * RFC 1035 - Domain names - implementation and specification
+ * RFC 2181 - Clarifications to the DNS Specification
+ *----------------------------------------------------------------------------*/
+
+/** @todo: define good default values (rfc compliance) */
+/** @todo: improve answer parsing, more checkings... */
+/** @todo: check RFC1035 - 7.3. Processing responses */
+
+/*-----------------------------------------------------------------------------
+ * Includes
+ *----------------------------------------------------------------------------*/
+
+#include "lwip/opt.h"
+
+#if LWIP_DNS /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/udp.h"
+#include "lwip/mem.h"
+#include "lwip/memp.h"
+#include "lwip/dns.h"
+
+#include <string.h>
+
+/** DNS server IP address */
+#ifndef DNS_SERVER_ADDRESS
+#define DNS_SERVER_ADDRESS(ipaddr)        (ip4_addr_set_u32(ipaddr, ipaddr_addr("208.67.222.222"))) /* resolver1.opendns.com */
+#endif
+
+/** DNS server port address */
+#ifndef DNS_SERVER_PORT
+#define DNS_SERVER_PORT           53
+#endif
+
+/** DNS maximum number of retries when asking for a name, before "timeout". */
+#ifndef DNS_MAX_RETRIES
+#define DNS_MAX_RETRIES           4
+#endif
+
+/** DNS resource record max. TTL (one week as default) */
+#ifndef DNS_MAX_TTL
+#define DNS_MAX_TTL               604800
+#endif
+
+/* DNS protocol flags */
+#define DNS_FLAG1_RESPONSE        0x80
+#define DNS_FLAG1_OPCODE_STATUS   0x10
+#define DNS_FLAG1_OPCODE_INVERSE  0x08
+#define DNS_FLAG1_OPCODE_STANDARD 0x00
+#define DNS_FLAG1_AUTHORATIVE     0x04
+#define DNS_FLAG1_TRUNC           0x02
+#define DNS_FLAG1_RD              0x01
+#define DNS_FLAG2_RA              0x80
+#define DNS_FLAG2_ERR_MASK        0x0f
+#define DNS_FLAG2_ERR_NONE        0x00
+#define DNS_FLAG2_ERR_NAME        0x03
+
+/* DNS protocol states */
+#define DNS_STATE_UNUSED          0
+#define DNS_STATE_NEW             1
+#define DNS_STATE_ASKING          2
+#define DNS_STATE_DONE            3
+
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+/** DNS message header */
+struct dns_hdr {
+  PACK_STRUCT_FIELD(u16_t id);
+  PACK_STRUCT_FIELD(u8_t flags1);
+  PACK_STRUCT_FIELD(u8_t flags2);
+  PACK_STRUCT_FIELD(u16_t numquestions);
+  PACK_STRUCT_FIELD(u16_t numanswers);
+  PACK_STRUCT_FIELD(u16_t numauthrr);
+  PACK_STRUCT_FIELD(u16_t numextrarr);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+#define SIZEOF_DNS_HDR 12
+
+/** DNS query message structure.
+    No packing needed: only used locally on the stack. */
+struct dns_query {
+  /* DNS query record starts with either a domain name or a pointer
+     to a name already present somewhere in the packet. */
+  u16_t type;
+  u16_t cls;
+};
+#define SIZEOF_DNS_QUERY 4
+
+/** DNS answer message structure.
+    No packing needed: only used locally on the stack. */
+struct dns_answer {
+  /* DNS answer record starts with either a domain name or a pointer
+     to a name already present somewhere in the packet. */
+  u16_t type;
+  u16_t cls;
+  u32_t ttl;
+  u16_t len;
+};
+#define SIZEOF_DNS_ANSWER 10
+
+/** DNS table entry */
+struct dns_table_entry {
+  u8_t  state;
+  u8_t  numdns;
+  u8_t  tmr;
+  u8_t  retries;
+  u8_t  seqno;
+  u8_t  err;
+  u32_t ttl;
+  char name[DNS_MAX_NAME_LENGTH];
+  ip_addr_t ipaddr;
+  /* pointer to callback on DNS query done */
+  dns_found_callback found;
+  void *arg;
+};
+
+#if DNS_LOCAL_HOSTLIST
+
+#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
+/** Local host-list. For hostnames in this list, no
+ *  external name resolution is performed */
+static struct local_hostlist_entry *local_hostlist_dynamic;
+#else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
+
+/** Defining this allows the local_hostlist_static to be placed in a different
+ * linker section (e.g. FLASH) */
+#ifndef DNS_LOCAL_HOSTLIST_STORAGE_PRE
+#define DNS_LOCAL_HOSTLIST_STORAGE_PRE static
+#endif /* DNS_LOCAL_HOSTLIST_STORAGE_PRE */
+/** Defining this allows the local_hostlist_static to be placed in a different
+ * linker section (e.g. FLASH) */
+#ifndef DNS_LOCAL_HOSTLIST_STORAGE_POST
+#define DNS_LOCAL_HOSTLIST_STORAGE_POST
+#endif /* DNS_LOCAL_HOSTLIST_STORAGE_POST */
+DNS_LOCAL_HOSTLIST_STORAGE_PRE struct local_hostlist_entry local_hostlist_static[]
+  DNS_LOCAL_HOSTLIST_STORAGE_POST = DNS_LOCAL_HOSTLIST_INIT;
+
+#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
+
+static void dns_init_local();
+#endif /* DNS_LOCAL_HOSTLIST */
+
+
+/* forward declarations */
+static void dns_recv(void *s, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port);
+static void dns_check_entries(void);
+
+/*-----------------------------------------------------------------------------
+ * Globales
+ *----------------------------------------------------------------------------*/
+
+/* DNS variables */
+static struct udp_pcb        *dns_pcb;
+static u8_t                   dns_seqno;
+static struct dns_table_entry dns_table[DNS_TABLE_SIZE];
+static ip_addr_t              dns_servers[DNS_MAX_SERVERS];
+/** Contiguous buffer for processing responses */
+static u8_t                   dns_payload_buffer[LWIP_MEM_ALIGN_BUFFER(DNS_MSG_SIZE)];
+static u8_t*                  dns_payload;
+
+/**
+ * Initialize the resolver: set up the UDP pcb and configure the default server
+ * (DNS_SERVER_ADDRESS).
+ */
+void
+dns_init()
+{
+  ip_addr_t dnsserver;
+
+  dns_payload = (u8_t *)LWIP_MEM_ALIGN(dns_payload_buffer);
+  
+  /* initialize default DNS server address */
+  DNS_SERVER_ADDRESS(&dnsserver);
+
+  LWIP_DEBUGF(DNS_DEBUG, ("dns_init: initializing\n"));
+
+  /* if dns client not yet initialized... */
+  if (dns_pcb == NULL) {
+    dns_pcb = udp_new();
+
+    if (dns_pcb != NULL) {
+      /* initialize DNS table not needed (initialized to zero since it is a
+       * global variable) */
+      LWIP_ASSERT("For implicit initialization to work, DNS_STATE_UNUSED needs to be 0",
+        DNS_STATE_UNUSED == 0);
+
+      /* initialize DNS client */
+      udp_bind(dns_pcb, IP_ADDR_ANY, 0);
+      udp_recv(dns_pcb, dns_recv, NULL);
+
+      /* initialize default DNS primary server */
+      dns_setserver(0, &dnsserver);
+    }
+  }
+#if DNS_LOCAL_HOSTLIST
+  dns_init_local();
+#endif
+}
+
+/**
+ * Initialize one of the DNS servers.
+ *
+ * @param numdns the index of the DNS server to set must be < DNS_MAX_SERVERS
+ * @param dnsserver IP address of the DNS server to set
+ */
+void
+dns_setserver(u8_t numdns, ip_addr_t *dnsserver)
+{
+  /*
+   * hpa: the lwip code has the dnsserver->addr != 0 test, but that would
+   * seem to indicate that there is no way to cancel a previously given
+   * DNS server...
+   */
+  if ((numdns < DNS_MAX_SERVERS) && (dns_pcb != NULL) &&
+      (dnsserver != NULL) /* && !ip_addr_isany(dnsserver) */) {
+    dns_servers[numdns] = (*dnsserver);
+  }
+}
+
+/**
+ * Obtain one of the currently configured DNS server.
+ *
+ * @param numdns the index of the DNS server
+ * @return IP address of the indexed DNS server or "ip_addr_any" if the DNS
+ *         server has not been configured.
+ */
+ip_addr_t
+dns_getserver(u8_t numdns)
+{
+  if (numdns < DNS_MAX_SERVERS) {
+    return dns_servers[numdns];
+  } else {
+    return *IP_ADDR_ANY;
+  }
+}
+
+/**
+ * The DNS resolver client timer - handle retries and timeouts and should
+ * be called every DNS_TMR_INTERVAL milliseconds (every second by default).
+ */
+void
+dns_tmr(void)
+{
+  if (dns_pcb != NULL) {
+    LWIP_DEBUGF(DNS_DEBUG, ("dns_tmr: dns_check_entries\n"));
+    dns_check_entries();
+  }
+}
+
+#if DNS_LOCAL_HOSTLIST
+static void
+dns_init_local()
+{
+#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT)
+  int i;
+  struct local_hostlist_entry *entry;
+  /* Dynamic: copy entries from DNS_LOCAL_HOSTLIST_INIT to list */
+  struct local_hostlist_entry local_hostlist_init[] = DNS_LOCAL_HOSTLIST_INIT;
+  size_t namelen;
+  for (i = 0; i < sizeof(local_hostlist_init) / sizeof(struct local_hostlist_entry); i++) {
+    struct local_hostlist_entry *init_entry = &local_hostlist_init[i];
+    LWIP_ASSERT("invalid host name (NULL)", init_entry->name != NULL);
+    namelen = strlen(init_entry->name);
+    LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
+    entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
+    LWIP_ASSERT("mem-error in dns_init_local", entry != NULL);
+    if (entry != NULL) {
+      entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
+      MEMCPY((char*)entry->name, init_entry->name, namelen);
+      ((char*)entry->name)[namelen] = 0;
+      entry->addr = init_entry->addr;
+      entry->next = local_hostlist_dynamic;
+      local_hostlist_dynamic = entry;
+    }
+  }
+#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT) */
+}
+
+/**
+ * Scans the local host-list for a hostname.
+ *
+ * @param hostname Hostname to look for in the local host-list
+ * @return The first IP address for the hostname in the local host-list or
+ *         IPADDR_NONE if not found.
+ */
+static u32_t
+dns_lookup_local(const char *hostname)
+{
+#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
+  struct local_hostlist_entry *entry = local_hostlist_dynamic;
+  while(entry != NULL) {
+    if(strcmp(entry->name, hostname) == 0) {
+      return ip4_addr_get_u32(&entry->addr);
+    }
+    entry = entry->next;
+  }
+#else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
+  int i;
+  for (i = 0; i < sizeof(local_hostlist_static) / sizeof(struct local_hostlist_entry); i++) {
+    if(strcmp(local_hostlist_static[i].name, hostname) == 0) {
+      return ip4_addr_get_u32(&local_hostlist_static[i].addr);
+    }
+  }
+#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
+  return IPADDR_NONE;
+}
+
+#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
+/** Remove all entries from the local host-list for a specific hostname
+ * and/or IP addess
+ *
+ * @param hostname hostname for which entries shall be removed from the local
+ *                 host-list
+ * @param addr address for which entries shall be removed from the local host-list
+ * @return the number of removed entries
+ */
+int
+dns_local_removehost(const char *hostname, const ip_addr_t *addr)
+{
+  int removed = 0;
+  struct local_hostlist_entry *entry = local_hostlist_dynamic;
+  struct local_hostlist_entry *last_entry = NULL;
+  while (entry != NULL) {
+    if (((hostname == NULL) || !strcmp(entry->name, hostname)) &&
+        ((addr == NULL) || ip_addr_cmp(&entry->addr, addr))) {
+      struct local_hostlist_entry *free_entry;
+      if (last_entry != NULL) {
+        last_entry->next = entry->next;
+      } else {
+        local_hostlist_dynamic = entry->next;
+      }
+      free_entry = entry;
+      entry = entry->next;
+      memp_free(MEMP_LOCALHOSTLIST, free_entry);
+      removed++;
+    } else {
+      last_entry = entry;
+      entry = entry->next;
+    }
+  }
+  return removed;
+}
+
+/**
+ * Add a hostname/IP address pair to the local host-list.
+ * Duplicates are not checked.
+ *
+ * @param hostname hostname of the new entry
+ * @param addr IP address of the new entry
+ * @return ERR_OK if succeeded or ERR_MEM on memory error
+ */
+err_t
+dns_local_addhost(const char *hostname, const ip_addr_t *addr)
+{
+  struct local_hostlist_entry *entry;
+  size_t namelen;
+  LWIP_ASSERT("invalid host name (NULL)", hostname != NULL);
+  namelen = strlen(hostname);
+  LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
+  entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
+  if (entry == NULL) {
+    return ERR_MEM;
+  }
+  entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
+  MEMCPY((char*)entry->name, hostname, namelen);
+  ((char*)entry->name)[namelen] = 0;
+  ip_addr_copy(entry->addr, *addr);
+  entry->next = local_hostlist_dynamic;
+  local_hostlist_dynamic = entry;
+  return ERR_OK;
+}
+#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC*/
+#endif /* DNS_LOCAL_HOSTLIST */
+
+/**
+ * Look up a hostname in the array of known hostnames.
+ *
+ * @note This function only looks in the internal array of known
+ * hostnames, it does not send out a query for the hostname if none
+ * was found. The function dns_enqueue() can be used to send a query
+ * for a hostname.
+ *
+ * @param name the hostname to look up
+ * @return the hostname's IP address, as u32_t (instead of ip_addr_t to
+ *         better check for failure: != IPADDR_NONE) or IPADDR_NONE if the hostname
+ *         was not found in the cached dns_table.
+ */
+static u32_t
+dns_lookup(const char *name)
+{
+  u8_t i;
+#if DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN)
+  u32_t addr;
+#endif /* DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN) */
+#if DNS_LOCAL_HOSTLIST
+  if ((addr = dns_lookup_local(name)) != IPADDR_NONE) {
+    return addr;
+  }
+#endif /* DNS_LOCAL_HOSTLIST */
+#ifdef DNS_LOOKUP_LOCAL_EXTERN
+  if((addr = DNS_LOOKUP_LOCAL_EXTERN(name)) != IPADDR_NONE) {
+    return addr;
+  }
+#endif /* DNS_LOOKUP_LOCAL_EXTERN */
+
+  /* Walk through name list, return entry if found. If not, return NULL. */
+  for (i = 0; i < DNS_TABLE_SIZE; ++i) {
+    if ((dns_table[i].state == DNS_STATE_DONE) &&
+        (strcmp(name, dns_table[i].name) == 0)) {
+      LWIP_DEBUGF(DNS_DEBUG, ("dns_lookup: \"%s\": found = ", name));
+      ip_addr_debug_print(DNS_DEBUG, &(dns_table[i].ipaddr));
+      LWIP_DEBUGF(DNS_DEBUG, ("\n"));
+      return ip4_addr_get_u32(&dns_table[i].ipaddr);
+    }
+  }
+
+  return IPADDR_NONE;
+}
+
+#if DNS_DOES_NAME_CHECK
+/**
+ * Compare the "dotted" name "query" with the encoded name "response"
+ * to make sure an answer from the DNS server matches the current dns_table
+ * entry (otherwise, answers might arrive late for hostname not on the list
+ * any more).
+ *
+ * @param query hostname (not encoded) from the dns_table
+ * @param response encoded hostname in the DNS response
+ * @return 0: names equal; 1: names differ
+ */
+static u8_t
+dns_compare_name(unsigned char *query, unsigned char *response)
+{
+  unsigned char n;
+
+  do {
+    n = *response++;
+    /** @see RFC 1035 - 4.1.4. Message compression */
+    if ((n & 0xc0) == 0xc0) {
+      /* Compressed name */
+      break;
+    } else {
+      /* Not compressed name */
+      while (n > 0) {
+        if ((*query) != (*response)) {
+          return 1;
+        }
+        ++response;
+        ++query;
+        --n;
+      };
+      ++query;
+    }
+  } while (*response != 0);
+
+  return 0;
+}
+#endif /* DNS_DOES_NAME_CHECK */
+
+/**
+ * Walk through a compact encoded DNS name and return the end of the name.
+ *
+ * @param query encoded DNS name in the DNS server response
+ * @return end of the name
+ */
+static unsigned char *
+dns_parse_name(unsigned char *query)
+{
+  unsigned char n;
+
+  do {
+    n = *query++;
+    /** @see RFC 1035 - 4.1.4. Message compression */
+    if ((n & 0xc0) == 0xc0) {
+      /* Compressed name */
+      break;
+    } else {
+      /* Not compressed name */
+      while (n > 0) {
+        ++query;
+        --n;
+      };
+    }
+  } while (*query != 0);
+
+  return query + 1;
+}
+
+/**
+ * Send a DNS query packet.
+ *
+ * @param numdns index of the DNS server in the dns_servers table
+ * @param name hostname to query
+ * @param id index of the hostname in dns_table, used as transaction ID in the
+ *        DNS query packet
+ * @return ERR_OK if packet is sent; an err_t indicating the problem otherwise
+ */
+static err_t
+dns_send(u8_t numdns, const char* name, u8_t id)
+{
+  err_t err;
+  struct dns_hdr *hdr;
+  struct dns_query qry;
+  struct pbuf *p;
+  char *query, *nptr;
+  const char *pHostname;
+  u8_t n;
+
+  LWIP_DEBUGF(DNS_DEBUG, ("dns_send: dns_servers[%"U16_F"] \"%s\": request\n",
+              (u16_t)(numdns), name));
+  LWIP_ASSERT("dns server out of array", numdns < DNS_MAX_SERVERS);
+  LWIP_ASSERT("dns server has no IP address set", !ip_addr_isany(&dns_servers[numdns]));
+
+  /* if here, we have either a new query or a retry on a previous query to process */
+  p = pbuf_alloc(PBUF_TRANSPORT, SIZEOF_DNS_HDR + DNS_MAX_NAME_LENGTH +
+                 SIZEOF_DNS_QUERY, PBUF_RAM);
+  if (p != NULL) {
+    LWIP_ASSERT("pbuf must be in one piece", p->next == NULL);
+    /* fill dns header */
+    hdr = (struct dns_hdr*)p->payload;
+    memset(hdr, 0, SIZEOF_DNS_HDR);
+    hdr->id = htons(id);
+    hdr->flags1 = DNS_FLAG1_RD;
+    hdr->numquestions = PP_HTONS(1);
+    query = (char*)hdr + SIZEOF_DNS_HDR;
+    pHostname = name;
+    --pHostname;
+
+    /* convert hostname into suitable query format. */
+    do {
+      ++pHostname;
+      nptr = query;
+      ++query;
+      for(n = 0; *pHostname != '.' && *pHostname != 0; ++pHostname) {
+        *query = *pHostname;
+        ++query;
+        ++n;
+      }
+      *nptr = n;
+    } while(*pHostname != 0);
+    *query++='\0';
+
+    /* fill dns query */
+    qry.type = PP_HTONS(DNS_RRTYPE_A);
+    qry.cls = PP_HTONS(DNS_RRCLASS_IN);
+    SMEMCPY(query, &qry, SIZEOF_DNS_QUERY);
+
+    /* resize pbuf to the exact dns query */
+    pbuf_realloc(p, (u16_t)((query + SIZEOF_DNS_QUERY) - ((char*)(p->payload))));
+
+    /* connect to the server for faster receiving */
+    udp_connect(dns_pcb, &dns_servers[numdns], DNS_SERVER_PORT);
+    /* send dns packet */
+    err = udp_sendto(dns_pcb, p, &dns_servers[numdns], DNS_SERVER_PORT);
+
+    /* free pbuf */
+    pbuf_free(p);
+  } else {
+    err = ERR_MEM;
+  }
+
+  return err;
+}
+
+/**
+ * dns_check_entry() - see if pEntry has not yet been queried and, if so, sends out a query.
+ * Check an entry in the dns_table:
+ * - send out query for new entries
+ * - retry old pending entries on timeout (also with different servers)
+ * - remove completed entries from the table if their TTL has expired
+ *
+ * @param i index of the dns_table entry to check
+ */
+static void
+dns_check_entry(u8_t i)
+{
+  err_t err;
+  struct dns_table_entry *pEntry = &dns_table[i];
+
+  LWIP_ASSERT("array index out of bounds", i < DNS_TABLE_SIZE);
+
+  switch(pEntry->state) {
+
+    case DNS_STATE_NEW: {
+      /* initialize new entry */
+      pEntry->state   = DNS_STATE_ASKING;
+      pEntry->numdns  = 0;
+      pEntry->tmr     = 1;
+      pEntry->retries = 0;
+      
+      /* send DNS packet for this entry */
+      err = dns_send(pEntry->numdns, pEntry->name, i);
+      if (err != ERR_OK) {
+        LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING,
+                    ("dns_send returned error: %s\n", lwip_strerr(err)));
+      }
+      break;
+    }
+
+    case DNS_STATE_ASKING: {
+      if (--pEntry->tmr == 0) {
+        if (++pEntry->retries == DNS_MAX_RETRIES) {
+          if ((pEntry->numdns+1<DNS_MAX_SERVERS) && !ip_addr_isany(&dns_servers[pEntry->numdns+1])) {
+            /* change of server */
+            pEntry->numdns++;
+            pEntry->tmr     = 1;
+            pEntry->retries = 0;
+            break;
+          } else {
+            LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": timeout\n", pEntry->name));
+            /* call specified callback function if provided */
+            if (pEntry->found)
+              (*pEntry->found)(pEntry->name, NULL, pEntry->arg);
+            /* flush this entry */
+            pEntry->state   = DNS_STATE_UNUSED;
+            pEntry->found   = NULL;
+            break;
+          }
+        }
+
+        /* wait longer for the next retry */
+        pEntry->tmr = pEntry->retries;
+
+        /* send DNS packet for this entry */
+        err = dns_send(pEntry->numdns, pEntry->name, i);
+        if (err != ERR_OK) {
+          LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING,
+                      ("dns_send returned error: %s\n", lwip_strerr(err)));
+        }
+      }
+      break;
+    }
+
+    case DNS_STATE_DONE: {
+      /* if the time to live is nul */
+      if (--pEntry->ttl == 0) {
+        LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": flush\n", pEntry->name));
+        /* flush this entry */
+        pEntry->state = DNS_STATE_UNUSED;
+        pEntry->found = NULL;
+      }
+      break;
+    }
+    case DNS_STATE_UNUSED:
+      /* nothing to do */
+      break;
+    default:
+      LWIP_ASSERT("unknown dns_table entry state:", 0);
+      break;
+  }
+}
+
+/**
+ * Call dns_check_entry for each entry in dns_table - check all entries.
+ */
+static void
+dns_check_entries(void)
+{
+  u8_t i;
+
+  for (i = 0; i < DNS_TABLE_SIZE; ++i) {
+    dns_check_entry(i);
+  }
+}
+
+/**
+ * Receive input function for DNS response packets arriving for the dns UDP pcb.
+ *
+ * @params see udp.h
+ */
+static void
+dns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port)
+{
+  u16_t i;
+  char *pHostname;
+  struct dns_hdr *hdr;
+  struct dns_answer ans;
+  struct dns_table_entry *pEntry;
+  u16_t nquestions, nanswers;
+
+  LWIP_UNUSED_ARG(arg);
+  LWIP_UNUSED_ARG(pcb);
+  LWIP_UNUSED_ARG(addr);
+  LWIP_UNUSED_ARG(port);
+
+  /* is the dns message too big ? */
+  if (p->tot_len > DNS_MSG_SIZE) {
+    LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too big\n"));
+    /* free pbuf and return */
+    goto memerr;
+  }
+
+  /* is the dns message big enough ? */
+  if (p->tot_len < (SIZEOF_DNS_HDR + SIZEOF_DNS_QUERY + SIZEOF_DNS_ANSWER)) {
+    LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too small\n"));
+    /* free pbuf and return */
+    goto memerr;
+  }
+
+  /* copy dns payload inside static buffer for processing */ 
+  if (pbuf_copy_partial(p, dns_payload, p->tot_len, 0) == p->tot_len) {
+    /* The ID in the DNS header should be our entry into the name table. */
+    hdr = (struct dns_hdr*)dns_payload;
+    i = htons(hdr->id);
+    if (i < DNS_TABLE_SIZE) {
+      pEntry = &dns_table[i];
+      if(pEntry->state == DNS_STATE_ASKING) {
+        /* This entry is now completed. */
+        pEntry->state = DNS_STATE_DONE;
+        pEntry->err   = hdr->flags2 & DNS_FLAG2_ERR_MASK;
+
+        /* We only care about the question(s) and the answers. The authrr
+           and the extrarr are simply discarded. */
+        nquestions = htons(hdr->numquestions);
+        nanswers   = htons(hdr->numanswers);
+
+        /* Check for error. If so, call callback to inform. */
+        if (((hdr->flags1 & DNS_FLAG1_RESPONSE) == 0) || (pEntry->err != 0) || (nquestions != 1)) {
+          LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in flags\n", pEntry->name));
+          /* call callback to indicate error, clean up memory and return */
+          goto responseerr;
+        }
+
+#if DNS_DOES_NAME_CHECK
+        /* Check if the name in the "question" part match with the name in the entry. */
+        if (dns_compare_name((unsigned char *)(pEntry->name), (unsigned char *)dns_payload + SIZEOF_DNS_HDR) != 0) {
+          LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", pEntry->name));
+          /* call callback to indicate error, clean up memory and return */
+          goto responseerr;
+        }
+#endif /* DNS_DOES_NAME_CHECK */
+
+        /* Skip the name in the "question" part */
+        pHostname = (char *) dns_parse_name((unsigned char *)dns_payload + SIZEOF_DNS_HDR) + SIZEOF_DNS_QUERY;
+
+        while (nanswers > 0) {
+          /* skip answer resource record's host name */
+          pHostname = (char *) dns_parse_name((unsigned char *)pHostname);
+
+          /* Check for IP address type and Internet class. Others are discarded. */
+          SMEMCPY(&ans, pHostname, SIZEOF_DNS_ANSWER);
+          if((ans.type == PP_HTONS(DNS_RRTYPE_A)) && (ans.cls == PP_HTONS(DNS_RRCLASS_IN)) &&
+             (ans.len == PP_HTONS(sizeof(ip_addr_t))) ) {
+            /* read the answer resource record's TTL, and maximize it if needed */
+            pEntry->ttl = ntohl(ans.ttl);
+            if (pEntry->ttl > DNS_MAX_TTL) {
+              pEntry->ttl = DNS_MAX_TTL;
+            }
+            /* read the IP address after answer resource record's header */
+            SMEMCPY(&(pEntry->ipaddr), (pHostname+SIZEOF_DNS_ANSWER), sizeof(ip_addr_t));
+            LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response = ", pEntry->name));
+            ip_addr_debug_print(DNS_DEBUG, (&(pEntry->ipaddr)));
+            LWIP_DEBUGF(DNS_DEBUG, ("\n"));
+            /* call specified callback function if provided */
+            if (pEntry->found) {
+              (*pEntry->found)(pEntry->name, &pEntry->ipaddr, pEntry->arg);
+            }
+            /* deallocate memory and return */
+            goto memerr;
+          } else {
+            pHostname = pHostname + SIZEOF_DNS_ANSWER + htons(ans.len);
+          }
+          --nanswers;
+        }
+        LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in response\n", pEntry->name));
+        /* call callback to indicate error, clean up memory and return */
+        goto responseerr;
+      }
+    }
+  }
+
+  /* deallocate memory and return */
+  goto memerr;
+
+responseerr:
+  /* ERROR: call specified callback function with NULL as name to indicate an error */
+  if (pEntry->found) {
+    (*pEntry->found)(pEntry->name, NULL, pEntry->arg);
+  }
+  /* flush this entry */
+  pEntry->state = DNS_STATE_UNUSED;
+  pEntry->found = NULL;
+
+memerr:
+  /* free pbuf */
+  pbuf_free(p);
+  return;
+}
+
+/**
+ * Queues a new hostname to resolve and sends out a DNS query for that hostname
+ *
+ * @param name the hostname that is to be queried
+ * @param found a callback founction to be called on success, failure or timeout
+ * @param callback_arg argument to pass to the callback function
+ * @return @return a err_t return code.
+ */
+static err_t
+dns_enqueue(const char *name, dns_found_callback found, void *callback_arg)
+{
+  u8_t i;
+  u8_t lseq, lseqi;
+  struct dns_table_entry *pEntry = NULL;
+  size_t namelen;
+
+  /* search an unused entry, or the oldest one */
+  lseq = lseqi = 0;
+  for (i = 0; i < DNS_TABLE_SIZE; ++i) {
+    pEntry = &dns_table[i];
+    /* is it an unused entry ? */
+    if (pEntry->state == DNS_STATE_UNUSED)
+      break;
+
+    /* check if this is the oldest completed entry */
+    if (pEntry->state == DNS_STATE_DONE) {
+      if ((dns_seqno - pEntry->seqno) > lseq) {
+        lseq = dns_seqno - pEntry->seqno;
+        lseqi = i;
+      }
+    }
+  }
+
+  /* if we don't have found an unused entry, use the oldest completed one */
+  if (i == DNS_TABLE_SIZE) {
+    if ((lseqi >= DNS_TABLE_SIZE) || (dns_table[lseqi].state != DNS_STATE_DONE)) {
+      /* no entry can't be used now, table is full */
+      LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS entries table is full\n", name));
+      return ERR_MEM;
+    } else {
+      /* use the oldest completed one */
+      i = lseqi;
+      pEntry = &dns_table[i];
+    }
+  }
+
+  /* use this entry */
+  LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS entry %"U16_F"\n", name, (u16_t)(i)));
+
+  /* fill the entry */
+  pEntry->state = DNS_STATE_NEW;
+  pEntry->seqno = dns_seqno++;
+  pEntry->found = found;
+  pEntry->arg   = callback_arg;
+  namelen = LWIP_MIN(strlen(name), DNS_MAX_NAME_LENGTH-1);
+  MEMCPY(pEntry->name, name, namelen);
+  pEntry->name[namelen] = 0;
+
+  /* force to send query without waiting timer */
+  dns_check_entry(i);
+
+  /* dns query is enqueued */
+  return ERR_INPROGRESS;
+}
+
+/**
+ * Resolve a hostname (string) into an IP address.
+ * NON-BLOCKING callback version for use with raw API!!!
+ *
+ * Returns immediately with one of err_t return codes:
+ * - ERR_OK if hostname is a valid IP address string or the host
+ *   name is already in the local names table.
+ * - ERR_INPROGRESS enqueue a request to be sent to the DNS server
+ *   for resolution if no errors are present.
+ * - ERR_ARG: dns client not initialized or invalid hostname
+ *
+ * @param hostname the hostname that is to be queried
+ * @param addr pointer to a ip_addr_t where to store the address if it is already
+ *             cached in the dns_table (only valid if ERR_OK is returned!)
+ * @param found a callback function to be called on success, failure or timeout (only if
+ *              ERR_INPROGRESS is returned!)
+ * @param callback_arg argument to pass to the callback function
+ * @return a err_t return code.
+ */
+err_t
+dns_gethostbyname(const char *hostname, ip_addr_t *addr, dns_found_callback found,
+                  void *callback_arg)
+{
+  u32_t ipaddr;
+  /* not initialized or no valid server yet, or invalid addr pointer
+   * or invalid hostname or invalid hostname length */
+  if ((dns_pcb == NULL) || (addr == NULL) ||
+      (!hostname) || (!hostname[0]) ||
+      (strlen(hostname) >= DNS_MAX_NAME_LENGTH)) {
+    return ERR_ARG;
+  }
+
+#if LWIP_HAVE_LOOPIF
+  if (strcmp(hostname, "localhost")==0) {
+    ip_addr_set_loopback(addr);
+    return ERR_OK;
+  }
+#endif /* LWIP_HAVE_LOOPIF */
+
+  /* host name already in octet notation? set ip addr and return ERR_OK */
+  ipaddr = ipaddr_addr(hostname);
+  if (ipaddr == IPADDR_NONE) {
+    /* already have this address cached? */
+    ipaddr = dns_lookup(hostname);
+  }
+  if (ipaddr != IPADDR_NONE) {
+    ip4_addr_set_u32(addr, ipaddr);
+    return ERR_OK;
+  }
+
+  /* queue query with specified callback */
+  return dns_enqueue(hostname, found, callback_arg);
+}
+
+#endif /* LWIP_DNS */
diff --git a/core/lwip/src/core/init.c b/core/lwip/src/core/init.c
new file mode 100644
index 00000000..36038350
--- /dev/null
+++ b/core/lwip/src/core/init.c
@@ -0,0 +1,306 @@
+/**
+ * @file
+ * Modules initialization
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#include "lwip/init.h"
+#include "lwip/stats.h"
+#include "lwip/sys.h"
+#include "lwip/mem.h"
+#include "lwip/memp.h"
+#include "lwip/pbuf.h"
+#include "lwip/netif.h"
+#include "lwip/sockets.h"
+#include "lwip/ip.h"
+#include "lwip/raw.h"
+#include "lwip/udp.h"
+#include "lwip/tcp_impl.h"
+#include "lwip/snmp_msg.h"
+#include "lwip/autoip.h"
+#include "lwip/igmp.h"
+#include "lwip/dns.h"
+#include "lwip/timers.h"
+#include "netif/etharp.h"
+
+/* Compile-time sanity checks for configuration errors.
+ * These can be done independently of LWIP_DEBUG, without penalty.
+ */
+#ifndef BYTE_ORDER
+  #error "BYTE_ORDER is not defined, you have to define it in your cc.h"
+#endif
+#if (!IP_SOF_BROADCAST && IP_SOF_BROADCAST_RECV)
+  #error "If you want to use broadcast filter per pcb on recv operations, you have to define IP_SOF_BROADCAST=1 in your lwipopts.h"
+#endif
+#if (!LWIP_ARP && ARP_QUEUEING)
+  #error "If you want to use ARP Queueing, you have to define LWIP_ARP=1 in your lwipopts.h"
+#endif
+#if (!LWIP_UDP && LWIP_UDPLITE)
+  #error "If you want to use UDP Lite, you have to define LWIP_UDP=1 in your lwipopts.h"
+#endif
+#if (!LWIP_UDP && LWIP_SNMP)
+  #error "If you want to use SNMP, you have to define LWIP_UDP=1 in your lwipopts.h"
+#endif
+#if (!LWIP_UDP && LWIP_DHCP)
+  #error "If you want to use DHCP, you have to define LWIP_UDP=1 in your lwipopts.h"
+#endif
+#if (!LWIP_UDP && LWIP_IGMP)
+  #error "If you want to use IGMP, you have to define LWIP_UDP=1 in your lwipopts.h"
+#endif
+#if (!LWIP_UDP && LWIP_SNMP)
+  #error "If you want to use SNMP, you have to define LWIP_UDP=1 in your lwipopts.h"
+#endif
+#if (!LWIP_UDP && LWIP_DNS)
+  #error "If you want to use DNS, you have to define LWIP_UDP=1 in your lwipopts.h"
+#endif
+#if (LWIP_ARP && ARP_QUEUEING && (MEMP_NUM_ARP_QUEUE<=0))
+  #error "If you want to use ARP Queueing, you have to define MEMP_NUM_ARP_QUEUE>=1 in your lwipopts.h"
+#endif
+#if (LWIP_RAW && (MEMP_NUM_RAW_PCB<=0))
+  #error "If you want to use RAW, you have to define MEMP_NUM_RAW_PCB>=1 in your lwipopts.h"
+#endif
+#if (LWIP_UDP && (MEMP_NUM_UDP_PCB<=0))
+  #error "If you want to use UDP, you have to define MEMP_NUM_UDP_PCB>=1 in your lwipopts.h"
+#endif
+#if (LWIP_TCP && (MEMP_NUM_TCP_PCB<=0))
+  #error "If you want to use TCP, you have to define MEMP_NUM_TCP_PCB>=1 in your lwipopts.h"
+#endif
+#if (LWIP_TCP && (TCP_WND > 0xffff))
+  #error "If you want to use TCP, TCP_WND must fit in an u16_t, so, you have to reduce it in your lwipopts.h"
+#endif
+#if (LWIP_TCP && (TCP_SND_QUEUELEN > 0xffff))
+  #error "If you want to use TCP, TCP_SND_QUEUELEN must fit in an u16_t, so, you have to reduce it in your lwipopts.h"
+#endif
+#if (LWIP_TCP && (TCP_SND_QUEUELEN < 2))
+  #error "TCP_SND_QUEUELEN must be at least 2 for no-copy TCP writes to work"
+#endif
+#if (LWIP_TCP && ((TCP_MAXRTX > 12) || (TCP_SYNMAXRTX > 12)))
+  #error "If you want to use TCP, TCP_MAXRTX and TCP_SYNMAXRTX must less or equal to 12 (due to tcp_backoff table), so, you have to reduce them in your lwipopts.h"
+#endif
+#if (LWIP_TCP && TCP_LISTEN_BACKLOG && (TCP_DEFAULT_LISTEN_BACKLOG < 0) || (TCP_DEFAULT_LISTEN_BACKLOG > 0xff))
+  #error "If you want to use TCP backlog, TCP_DEFAULT_LISTEN_BACKLOG must fit into an u8_t"
+#endif
+#if (LWIP_IGMP && (MEMP_NUM_IGMP_GROUP<=1))
+  #error "If you want to use IGMP, you have to define MEMP_NUM_IGMP_GROUP>1 in your lwipopts.h"
+#endif
+#if (LWIP_NETIF_API && (NO_SYS==1))
+  #error "If you want to use NETIF API, you have to define NO_SYS=0 in your lwipopts.h"
+#endif
+#if ((LWIP_SOCKET || LWIP_NETCONN) && (NO_SYS==1))
+  #error "If you want to use Sequential API, you have to define NO_SYS=0 in your lwipopts.h"
+#endif
+#if ((LWIP_NETCONN || LWIP_SOCKET) && (MEMP_NUM_TCPIP_MSG_API<=0))
+  #error "If you want to use Sequential API, you have to define MEMP_NUM_TCPIP_MSG_API>=1 in your lwipopts.h"
+#endif
+#if (!LWIP_NETCONN && LWIP_SOCKET)
+  #error "If you want to use Socket API, you have to define LWIP_NETCONN=1 in your lwipopts.h"
+#endif
+#if (((!LWIP_DHCP) || (!LWIP_AUTOIP)) && LWIP_DHCP_AUTOIP_COOP)
+  #error "If you want to use DHCP/AUTOIP cooperation mode, you have to define LWIP_DHCP=1 and LWIP_AUTOIP=1 in your lwipopts.h"
+#endif
+#if (((!LWIP_DHCP) || (!LWIP_ARP)) && DHCP_DOES_ARP_CHECK)
+  #error "If you want to use DHCP ARP checking, you have to define LWIP_DHCP=1 and LWIP_ARP=1 in your lwipopts.h"
+#endif
+#if (!LWIP_ARP && LWIP_AUTOIP)
+  #error "If you want to use AUTOIP, you have to define LWIP_ARP=1 in your lwipopts.h"
+#endif
+#if (LWIP_SNMP && (SNMP_CONCURRENT_REQUESTS<=0))
+  #error "If you want to use SNMP, you have to define SNMP_CONCURRENT_REQUESTS>=1 in your lwipopts.h"
+#endif
+#if (LWIP_SNMP && (SNMP_TRAP_DESTINATIONS<=0))
+  #error "If you want to use SNMP, you have to define SNMP_TRAP_DESTINATIONS>=1 in your lwipopts.h"
+#endif
+#if (LWIP_TCP && ((LWIP_EVENT_API && LWIP_CALLBACK_API) || (!LWIP_EVENT_API && !LWIP_CALLBACK_API)))
+  #error "One and exactly one of LWIP_EVENT_API and LWIP_CALLBACK_API has to be enabled in your lwipopts.h"
+#endif
+/* There must be sufficient timeouts, taking into account requirements of the subsystems. */
+#if LWIP_TIMERS && (MEMP_NUM_SYS_TIMEOUT < (LWIP_TCP + IP_REASSEMBLY + LWIP_ARP + (2*LWIP_DHCP) + LWIP_AUTOIP + LWIP_IGMP + LWIP_DNS + PPP_SUPPORT))
+  #error "MEMP_NUM_SYS_TIMEOUT is too low to accomodate all required timeouts"
+#endif
+#if (IP_REASSEMBLY && (MEMP_NUM_REASSDATA > IP_REASS_MAX_PBUFS))
+  #error "MEMP_NUM_REASSDATA > IP_REASS_MAX_PBUFS doesn't make sense since each struct ip_reassdata must hold 2 pbufs at least!"
+#endif
+#if (MEM_LIBC_MALLOC && MEM_USE_POOLS)
+  #error "MEM_LIBC_MALLOC and MEM_USE_POOLS may not both be simultaneously enabled in your lwipopts.h"
+#endif
+#if (MEM_USE_POOLS && !MEMP_USE_CUSTOM_POOLS)
+  #error "MEM_USE_POOLS requires custom pools (MEMP_USE_CUSTOM_POOLS) to be enabled in your lwipopts.h"
+#endif
+#if (PBUF_POOL_BUFSIZE <= MEM_ALIGNMENT)
+  #error "PBUF_POOL_BUFSIZE must be greater than MEM_ALIGNMENT or the offset may take the full first pbuf"
+#endif
+#if (TCP_QUEUE_OOSEQ && !LWIP_TCP)
+  #error "TCP_QUEUE_OOSEQ requires LWIP_TCP"
+#endif
+#if (DNS_LOCAL_HOSTLIST && !DNS_LOCAL_HOSTLIST_IS_DYNAMIC && !(defined(DNS_LOCAL_HOSTLIST_INIT)))
+  #error "you have to define define DNS_LOCAL_HOSTLIST_INIT {{'host1', 0x123}, {'host2', 0x234}} to initialize DNS_LOCAL_HOSTLIST"
+#endif
+#if PPP_SUPPORT && !PPPOS_SUPPORT & !PPPOE_SUPPORT
+  #error "PPP_SUPPORT needs either PPPOS_SUPPORT or PPPOE_SUPPORT turned on"
+#endif
+#if !LWIP_ETHERNET && (LWIP_ARP || PPPOE_SUPPORT)
+  #error "LWIP_ETHERNET needs to be turned on for LWIP_ARP or PPPOE_SUPPORT"
+#endif
+#if LWIP_IGMP && !defined(LWIP_RAND)
+  #error "When using IGMP, LWIP_RAND() needs to be defined to a random-function returning an u32_t random value"
+#endif
+#if LWIP_TCPIP_CORE_LOCKING_INPUT && !LWIP_TCPIP_CORE_LOCKING
+  #error "When using LWIP_TCPIP_CORE_LOCKING_INPUT, LWIP_TCPIP_CORE_LOCKING must be enabled, too"
+#endif
+#if LWIP_TCP && LWIP_NETIF_TX_SINGLE_PBUF && !TCP_OVERSIZE
+  #error "LWIP_NETIF_TX_SINGLE_PBUF needs TCP_OVERSIZE enabled to create single-pbuf TCP packets"
+#endif
+#if IP_FRAG && IP_FRAG_USES_STATIC_BUF && LWIP_NETIF_TX_SINGLE_PBUF
+  #error "LWIP_NETIF_TX_SINGLE_PBUF does not work with IP_FRAG_USES_STATIC_BUF==1 as that creates pbuf queues"
+#endif
+
+
+/* Compile-time checks for deprecated options.
+ */
+#ifdef MEMP_NUM_TCPIP_MSG
+  #error "MEMP_NUM_TCPIP_MSG option is deprecated. Remove it from your lwipopts.h."
+#endif
+#ifdef MEMP_NUM_API_MSG
+  #error "MEMP_NUM_API_MSG option is deprecated. Remove it from your lwipopts.h."
+#endif
+#ifdef TCP_REXMIT_DEBUG
+  #error "TCP_REXMIT_DEBUG option is deprecated. Remove it from your lwipopts.h."
+#endif
+#ifdef RAW_STATS
+  #error "RAW_STATS option is deprecated. Remove it from your lwipopts.h."
+#endif
+#ifdef ETHARP_QUEUE_FIRST
+  #error "ETHARP_QUEUE_FIRST option is deprecated. Remove it from your lwipopts.h."
+#endif
+#ifdef ETHARP_ALWAYS_INSERT
+  #error "ETHARP_ALWAYS_INSERT option is deprecated. Remove it from your lwipopts.h."
+#endif
+
+#ifdef LWIP_DEBUG
+static void
+lwip_sanity_check(void)
+{
+  /* Warnings */
+#if LWIP_NETCONN
+  if (MEMP_NUM_NETCONN > (MEMP_NUM_TCP_PCB+MEMP_NUM_TCP_PCB_LISTEN+MEMP_NUM_UDP_PCB+MEMP_NUM_RAW_PCB))
+    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: MEMP_NUM_NETCONN should be less than the sum of MEMP_NUM_{TCP,RAW,UDP}_PCB+MEMP_NUM_TCP_PCB_LISTEN\n"));
+#endif /* LWIP_NETCONN */
+#if LWIP_TCP
+  if (MEMP_NUM_TCP_SEG < TCP_SND_QUEUELEN)
+    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: MEMP_NUM_TCP_SEG should be at least as big as TCP_SND_QUEUELEN\n"));
+  if (TCP_SND_BUF < 2 * TCP_MSS)
+    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: TCP_SND_BUF must be at least as much as (2 * TCP_MSS) for things to work smoothly\n"));
+  if (TCP_SND_QUEUELEN < (2 * (TCP_SND_BUF/TCP_MSS)))
+    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: TCP_SND_QUEUELEN must be at least as much as (2 * TCP_SND_BUF/TCP_MSS) for things to work\n"));
+  if (TCP_SNDLOWAT >= TCP_SND_BUF)
+    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: TCP_SNDLOWAT must be less than TCP_SND_BUF.\n"));
+  if (TCP_SNDQUEUELOWAT >= TCP_SND_QUEUELEN)
+    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: TCP_SNDQUEUELOWAT must be less than TCP_SND_QUEUELEN.\n"));
+  if (TCP_WND > (PBUF_POOL_SIZE*PBUF_POOL_BUFSIZE))
+    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: TCP_WND is larger than space provided by PBUF_POOL_SIZE*PBUF_POOL_BUFSIZE\n"));
+  if (TCP_WND < TCP_MSS)
+    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: TCP_WND is smaller than MSS\n"));
+#endif /* LWIP_TCP */
+#if LWIP_SOCKET
+  /* Check that the SO_* socket options and SOF_* lwIP-internal flags match */
+  if (SO_ACCEPTCONN != SOF_ACCEPTCONN)
+    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: SO_ACCEPTCONN != SOF_ACCEPTCONN\n"));
+  if (SO_REUSEADDR != SOF_REUSEADDR)
+    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: SO_REUSEADDR != SOF_REUSEADDR\n"));
+  if (SO_KEEPALIVE != SOF_KEEPALIVE)
+    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: SO_KEEPALIVE != SOF_KEEPALIVE\n"));
+  if (SO_BROADCAST != SOF_BROADCAST)
+    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: SO_BROADCAST != SOF_BROADCAST\n"));
+  if (SO_LINGER != SOF_LINGER)
+    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: SO_LINGER != SOF_LINGER\n"));
+#endif /* LWIP_SOCKET */
+}
+#else  /* LWIP_DEBUG */
+#define lwip_sanity_check()
+#endif /* LWIP_DEBUG */
+
+/**
+ * Perform Sanity check of user-configurable values, and initialize all modules.
+ */
+void
+lwip_init(void)
+{
+  /* Sanity check user-configurable values */
+  lwip_sanity_check();
+
+  /* Modules initialization */
+  stats_init();
+#if !NO_SYS
+  sys_init();
+#endif /* !NO_SYS */
+  lwip_mem_init();
+  memp_init();
+  pbuf_init();
+  netif_init();
+#if LWIP_SOCKET
+  lwip_socket_init();
+#endif /* LWIP_SOCKET */
+  ip_init();
+#if LWIP_ARP
+  etharp_init();
+#endif /* LWIP_ARP */
+#if LWIP_RAW
+  raw_init();
+#endif /* LWIP_RAW */
+#if LWIP_UDP
+  udp_init();
+#endif /* LWIP_UDP */
+#if LWIP_TCP
+  tcp_init();
+#endif /* LWIP_TCP */
+#if LWIP_SNMP
+  snmp_init();
+#endif /* LWIP_SNMP */
+#if LWIP_AUTOIP
+  autoip_init();
+#endif /* LWIP_AUTOIP */
+#if LWIP_IGMP
+  igmp_init();
+#endif /* LWIP_IGMP */
+#if LWIP_DNS
+  dns_init();
+#endif /* LWIP_DNS */
+
+#if LWIP_TIMERS
+  sys_timeouts_init();
+#endif /* LWIP_TIMERS */
+}
diff --git a/core/lwip/src/core/ipv4/autoip.c b/core/lwip/src/core/ipv4/autoip.c
new file mode 100644
index 00000000..92bb4591
--- /dev/null
+++ b/core/lwip/src/core/ipv4/autoip.c
@@ -0,0 +1,536 @@
+/**
+ * @file
+ * AutoIP Automatic LinkLocal IP Configuration
+ *
+ */
+
+/*
+ *
+ * Copyright (c) 2007 Dominik Spies <kontakt@dspies.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * Author: Dominik Spies <kontakt@dspies.de>
+ *
+ * This is a AutoIP implementation for the lwIP TCP/IP stack. It aims to conform
+ * with RFC 3927.
+ *
+ *
+ * Please coordinate changes and requests with Dominik Spies
+ * <kontakt@dspies.de>
+ */
+
+/*******************************************************************************
+ * USAGE:
+ * 
+ * define LWIP_AUTOIP 1  in your lwipopts.h
+ * 
+ * If you don't use tcpip.c (so, don't call, you don't call tcpip_init):
+ * - First, call autoip_init().
+ * - call autoip_tmr() all AUTOIP_TMR_INTERVAL msces,
+ *   that should be defined in autoip.h.
+ *   I recommend a value of 100. The value must divide 1000 with a remainder almost 0.
+ *   Possible values are 1000, 500, 333, 250, 200, 166, 142, 125, 111, 100 ....
+ *
+ * Without DHCP:
+ * - Call autoip_start() after netif_add().
+ * 
+ * With DHCP:
+ * - define LWIP_DHCP_AUTOIP_COOP 1 in your lwipopts.h.
+ * - Configure your DHCP Client.
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_AUTOIP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/mem.h"
+#include "lwip/udp.h"
+#include "lwip/ip_addr.h"
+#include "lwip/netif.h"
+#include "lwip/autoip.h"
+#include "netif/etharp.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+/* 169.254.0.0 */
+#define AUTOIP_NET         0xA9FE0000
+/* 169.254.1.0 */
+#define AUTOIP_RANGE_START (AUTOIP_NET | 0x0100)
+/* 169.254.254.255 */
+#define AUTOIP_RANGE_END   (AUTOIP_NET | 0xFEFF)
+
+
+/** Pseudo random macro based on netif informations.
+ * You could use "rand()" from the C Library if you define LWIP_AUTOIP_RAND in lwipopts.h */
+#ifndef LWIP_AUTOIP_RAND
+#define LWIP_AUTOIP_RAND(netif) ( (((u32_t)((netif->hwaddr[5]) & 0xff) << 24) | \
+                                   ((u32_t)((netif->hwaddr[3]) & 0xff) << 16) | \
+                                   ((u32_t)((netif->hwaddr[2]) & 0xff) << 8) | \
+                                   ((u32_t)((netif->hwaddr[4]) & 0xff))) + \
+                                   (netif->autoip?netif->autoip->tried_llipaddr:0))
+#endif /* LWIP_AUTOIP_RAND */
+
+/**
+ * Macro that generates the initial IP address to be tried by AUTOIP.
+ * If you want to override this, define it to something else in lwipopts.h.
+ */
+#ifndef LWIP_AUTOIP_CREATE_SEED_ADDR
+#define LWIP_AUTOIP_CREATE_SEED_ADDR(netif) \
+  htonl(AUTOIP_RANGE_START + ((u32_t)(((u8_t)(netif->hwaddr[4])) | \
+                 ((u32_t)((u8_t)(netif->hwaddr[5]))) << 8)))
+#endif /* LWIP_AUTOIP_CREATE_SEED_ADDR */
+
+/* static functions */
+static void autoip_handle_arp_conflict(struct netif *netif);
+
+/* creates a pseudo random LL IP-Address for a network interface */
+static void autoip_create_addr(struct netif *netif, ip_addr_t *ipaddr);
+
+/* sends an ARP probe */
+static err_t autoip_arp_probe(struct netif *netif);
+
+/* sends an ARP announce */
+static err_t autoip_arp_announce(struct netif *netif);
+
+/* configure interface for use with current LL IP-Address */
+static err_t autoip_bind(struct netif *netif);
+
+/* start sending probes for llipaddr */
+static void autoip_start_probing(struct netif *netif);
+
+/**
+ * Initialize this module
+ */
+void
+autoip_init(void)
+{
+  LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_init()\n"));
+}
+
+/** Set a statically allocated struct autoip to work with.
+ * Using this prevents autoip_start to allocate it using mem_malloc.
+ *
+ * @param netif the netif for which to set the struct autoip
+ * @param dhcp (uninitialised) dhcp struct allocated by the application
+ */
+void
+autoip_set_struct(struct netif *netif, struct autoip *autoip)
+{
+  LWIP_ASSERT("netif != NULL", netif != NULL);
+  LWIP_ASSERT("autoip != NULL", autoip != NULL);
+  LWIP_ASSERT("netif already has a struct autoip set", netif->autoip == NULL);
+
+  /* clear data structure */
+  memset(autoip, 0, sizeof(struct autoip));
+  /* autoip->state = AUTOIP_STATE_OFF; */
+  netif->autoip = autoip;
+}
+
+/** Restart AutoIP client and check the next address (conflict detected)
+ *
+ * @param netif The netif under AutoIP control
+ */
+static void
+autoip_restart(struct netif *netif)
+{
+  netif->autoip->tried_llipaddr++;
+  autoip_start(netif);
+}
+
+/**
+ * Handle a IP address conflict after an ARP conflict detection
+ */
+static void
+autoip_handle_arp_conflict(struct netif *netif)
+{
+  /* Somehow detect if we are defending or retreating */
+  unsigned char defend = 1; /* tbd */
+
+  if(defend) {
+    if(netif->autoip->lastconflict > 0) {
+      /* retreat, there was a conflicting ARP in the last
+       * DEFEND_INTERVAL seconds
+       */
+      LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+        ("autoip_handle_arp_conflict(): we are defending, but in DEFEND_INTERVAL, retreating\n"));
+
+      /* TODO: close all TCP sessions */
+      autoip_restart(netif);
+    } else {
+      LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+        ("autoip_handle_arp_conflict(): we are defend, send ARP Announce\n"));
+      autoip_arp_announce(netif);
+      netif->autoip->lastconflict = DEFEND_INTERVAL * AUTOIP_TICKS_PER_SECOND;
+    }
+  } else {
+    LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+      ("autoip_handle_arp_conflict(): we do not defend, retreating\n"));
+    /* TODO: close all TCP sessions */
+    autoip_restart(netif);
+  }
+}
+
+/**
+ * Create an IP-Address out of range 169.254.1.0 to 169.254.254.255
+ *
+ * @param netif network interface on which create the IP-Address
+ * @param ipaddr ip address to initialize
+ */
+static void
+autoip_create_addr(struct netif *netif, ip_addr_t *ipaddr)
+{
+  /* Here we create an IP-Address out of range 169.254.1.0 to 169.254.254.255
+   * compliant to RFC 3927 Section 2.1
+   * We have 254 * 256 possibilities */
+
+  u32_t addr = ntohl(LWIP_AUTOIP_CREATE_SEED_ADDR(netif));
+  addr += netif->autoip->tried_llipaddr;
+  addr = AUTOIP_NET | (addr & 0xffff);
+  /* Now, 169.254.0.0 <= addr <= 169.254.255.255 */ 
+
+  if (addr < AUTOIP_RANGE_START) {
+    addr += AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1;
+  }
+  if (addr > AUTOIP_RANGE_END) {
+    addr -= AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1;
+  }
+  LWIP_ASSERT("AUTOIP address not in range", (addr >= AUTOIP_RANGE_START) &&
+    (addr <= AUTOIP_RANGE_END));
+  ip4_addr_set_u32(ipaddr, htonl(addr));
+  
+  LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+    ("autoip_create_addr(): tried_llipaddr=%"U16_F", %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+    (u16_t)(netif->autoip->tried_llipaddr), ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr),
+    ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
+}
+
+/**
+ * Sends an ARP probe from a network interface
+ *
+ * @param netif network interface used to send the probe
+ */
+static err_t
+autoip_arp_probe(struct netif *netif)
+{
+  return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, &ethbroadcast,
+    (struct eth_addr *)netif->hwaddr, IP_ADDR_ANY, &ethzero,
+    &netif->autoip->llipaddr, ARP_REQUEST);
+}
+
+/**
+ * Sends an ARP announce from a network interface
+ *
+ * @param netif network interface used to send the announce
+ */
+static err_t
+autoip_arp_announce(struct netif *netif)
+{
+  return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, &ethbroadcast,
+    (struct eth_addr *)netif->hwaddr, &netif->autoip->llipaddr, &ethzero,
+    &netif->autoip->llipaddr, ARP_REQUEST);
+}
+
+/**
+ * Configure interface for use with current LL IP-Address
+ *
+ * @param netif network interface to configure with current LL IP-Address
+ */
+static err_t
+autoip_bind(struct netif *netif)
+{
+  struct autoip *autoip = netif->autoip;
+  ip_addr_t sn_mask, gw_addr;
+
+  LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
+    ("autoip_bind(netif=%p) %c%c%"U16_F" %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+    (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num,
+    ip4_addr1_16(&autoip->llipaddr), ip4_addr2_16(&autoip->llipaddr),
+    ip4_addr3_16(&autoip->llipaddr), ip4_addr4_16(&autoip->llipaddr)));
+
+  IP4_ADDR(&sn_mask, 255, 255, 0, 0);
+  IP4_ADDR(&gw_addr, 0, 0, 0, 0);
+
+  netif_set_ipaddr(netif, &autoip->llipaddr);
+  netif_set_netmask(netif, &sn_mask);
+  netif_set_gw(netif, &gw_addr);  
+
+  /* bring the interface up */
+  netif_set_up(netif);
+
+  return ERR_OK;
+}
+
+/**
+ * Start AutoIP client
+ *
+ * @param netif network interface on which start the AutoIP client
+ */
+err_t
+autoip_start(struct netif *netif)
+{
+  struct autoip *autoip = netif->autoip;
+  err_t result = ERR_OK;
+
+  if(netif_is_up(netif)) {
+    netif_set_down(netif);
+  }
+
+  /* Set IP-Address, Netmask and Gateway to 0 to make sure that
+   * ARP Packets are formed correctly
+   */
+  ip_addr_set_zero(&netif->ip_addr);
+  ip_addr_set_zero(&netif->netmask);
+  ip_addr_set_zero(&netif->gw);
+
+  LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+    ("autoip_start(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0],
+    netif->name[1], (u16_t)netif->num));
+  if(autoip == NULL) {
+    /* no AutoIP client attached yet? */
+    LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
+      ("autoip_start(): starting new AUTOIP client\n"));
+    autoip = (struct autoip *)mem_malloc(sizeof(struct autoip));
+    if(autoip == NULL) {
+      LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
+        ("autoip_start(): could not allocate autoip\n"));
+      return ERR_MEM;
+    }
+    memset(autoip, 0, sizeof(struct autoip));
+    /* store this AutoIP client in the netif */
+    netif->autoip = autoip;
+    LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_start(): allocated autoip"));
+  } else {
+    autoip->state = AUTOIP_STATE_OFF;
+    autoip->ttw = 0;
+    autoip->sent_num = 0;
+    ip_addr_set_zero(&autoip->llipaddr);
+    autoip->lastconflict = 0;
+  }
+
+  autoip_create_addr(netif, &(autoip->llipaddr));
+  autoip_start_probing(netif);
+
+  return result;
+}
+
+static void
+autoip_start_probing(struct netif *netif)
+{
+  struct autoip *autoip = netif->autoip;
+
+  autoip->state = AUTOIP_STATE_PROBING;
+  autoip->sent_num = 0;
+  LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+     ("autoip_start_probing(): changing state to PROBING: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+      ip4_addr1_16(&netif->autoip->llipaddr), ip4_addr2_16(&netif->autoip->llipaddr),
+      ip4_addr3_16(&netif->autoip->llipaddr), ip4_addr4_16(&netif->autoip->llipaddr)));
+
+  /* time to wait to first probe, this is randomly
+   * choosen out of 0 to PROBE_WAIT seconds.
+   * compliant to RFC 3927 Section 2.2.1
+   */
+  autoip->ttw = (u16_t)(LWIP_AUTOIP_RAND(netif) % (PROBE_WAIT * AUTOIP_TICKS_PER_SECOND));
+
+  /*
+   * if we tried more then MAX_CONFLICTS we must limit our rate for
+   * accquiring and probing address
+   * compliant to RFC 3927 Section 2.2.1
+   */
+  if(autoip->tried_llipaddr > MAX_CONFLICTS) {
+    autoip->ttw = RATE_LIMIT_INTERVAL * AUTOIP_TICKS_PER_SECOND;
+  }
+}
+
+/**
+ * Handle a possible change in the network configuration.
+ *
+ * If there is an AutoIP address configured, take the interface down
+ * and begin probing with the same address.
+ */
+void
+autoip_network_changed(struct netif *netif)
+{
+  if (netif->autoip && netif->autoip->state != AUTOIP_STATE_OFF) {
+    netif_set_down(netif);
+    autoip_start_probing(netif);
+  }
+}
+
+/**
+ * Stop AutoIP client
+ *
+ * @param netif network interface on which stop the AutoIP client
+ */
+err_t
+autoip_stop(struct netif *netif)
+{
+  netif->autoip->state = AUTOIP_STATE_OFF;
+  netif_set_down(netif);
+  return ERR_OK;
+}
+
+/**
+ * Has to be called in loop every AUTOIP_TMR_INTERVAL milliseconds
+ */
+void
+autoip_tmr()
+{
+  struct netif *netif = netif_list;
+  /* loop through netif's */
+  while (netif != NULL) {
+    /* only act on AutoIP configured interfaces */
+    if (netif->autoip != NULL) {
+      if(netif->autoip->lastconflict > 0) {
+        netif->autoip->lastconflict--;
+      }
+
+      LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
+        ("autoip_tmr() AutoIP-State: %"U16_F", ttw=%"U16_F"\n",
+        (u16_t)(netif->autoip->state), netif->autoip->ttw));
+
+      switch(netif->autoip->state) {
+        case AUTOIP_STATE_PROBING:
+          if(netif->autoip->ttw > 0) {
+            netif->autoip->ttw--;
+          } else {
+            if(netif->autoip->sent_num >= PROBE_NUM) {
+              netif->autoip->state = AUTOIP_STATE_ANNOUNCING;
+              netif->autoip->sent_num = 0;
+              netif->autoip->ttw = ANNOUNCE_WAIT * AUTOIP_TICKS_PER_SECOND;
+              LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+                 ("autoip_tmr(): changing state to ANNOUNCING: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+                  ip4_addr1_16(&netif->autoip->llipaddr), ip4_addr2_16(&netif->autoip->llipaddr),
+                  ip4_addr3_16(&netif->autoip->llipaddr), ip4_addr4_16(&netif->autoip->llipaddr)));
+            } else {
+              autoip_arp_probe(netif);
+              LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
+                ("autoip_tmr() PROBING Sent Probe\n"));
+              netif->autoip->sent_num++;
+              /* calculate time to wait to next probe */
+              netif->autoip->ttw = (u16_t)((LWIP_AUTOIP_RAND(netif) %
+                ((PROBE_MAX - PROBE_MIN) * AUTOIP_TICKS_PER_SECOND) ) +
+                PROBE_MIN * AUTOIP_TICKS_PER_SECOND);
+            }
+          }
+          break;
+
+        case AUTOIP_STATE_ANNOUNCING:
+          if(netif->autoip->ttw > 0) {
+            netif->autoip->ttw--;
+          } else {
+            if(netif->autoip->sent_num == 0) {
+             /* We are here the first time, so we waited ANNOUNCE_WAIT seconds
+              * Now we can bind to an IP address and use it.
+              *
+              * autoip_bind calls netif_set_up. This triggers a gratuitous ARP
+              * which counts as an announcement.
+              */
+              autoip_bind(netif);
+            } else {
+              autoip_arp_announce(netif);
+              LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
+                ("autoip_tmr() ANNOUNCING Sent Announce\n"));
+            }
+            netif->autoip->ttw = ANNOUNCE_INTERVAL * AUTOIP_TICKS_PER_SECOND;
+            netif->autoip->sent_num++;
+
+            if(netif->autoip->sent_num >= ANNOUNCE_NUM) {
+                netif->autoip->state = AUTOIP_STATE_BOUND;
+                netif->autoip->sent_num = 0;
+                netif->autoip->ttw = 0;
+                 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+                    ("autoip_tmr(): changing state to BOUND: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+                     ip4_addr1_16(&netif->autoip->llipaddr), ip4_addr2_16(&netif->autoip->llipaddr),
+                     ip4_addr3_16(&netif->autoip->llipaddr), ip4_addr4_16(&netif->autoip->llipaddr)));
+            }
+          }
+          break;
+      }
+    }
+    /* proceed to next network interface */
+    netif = netif->next;
+  }
+}
+
+/**
+ * Handles every incoming ARP Packet, called by etharp_arp_input.
+ *
+ * @param netif network interface to use for autoip processing
+ * @param hdr Incoming ARP packet
+ */
+void
+autoip_arp_reply(struct netif *netif, struct etharp_hdr *hdr)
+{
+  LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_arp_reply()\n"));
+  if ((netif->autoip != NULL) && (netif->autoip->state != AUTOIP_STATE_OFF)) {
+   /* when ip.src == llipaddr && hw.src != netif->hwaddr
+    *
+    * when probing  ip.dst == llipaddr && hw.src != netif->hwaddr
+    * we have a conflict and must solve it
+    */
+    ip_addr_t sipaddr, dipaddr;
+    struct eth_addr netifaddr;
+    ETHADDR16_COPY(netifaddr.addr, netif->hwaddr);
+
+    /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without
+     * structure packing (not using structure copy which breaks strict-aliasing rules).
+     */
+    IPADDR2_COPY(&sipaddr, &hdr->sipaddr);
+    IPADDR2_COPY(&dipaddr, &hdr->dipaddr);
+      
+    if ((netif->autoip->state == AUTOIP_STATE_PROBING) ||
+        ((netif->autoip->state == AUTOIP_STATE_ANNOUNCING) &&
+         (netif->autoip->sent_num == 0))) {
+     /* RFC 3927 Section 2.2.1:
+      * from beginning to after ANNOUNCE_WAIT
+      * seconds we have a conflict if
+      * ip.src == llipaddr OR
+      * ip.dst == llipaddr && hw.src != own hwaddr
+      */
+      if ((ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr)) ||
+          (ip_addr_cmp(&dipaddr, &netif->autoip->llipaddr) &&
+           !eth_addr_cmp(&netifaddr, &hdr->shwaddr))) {
+        LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
+          ("autoip_arp_reply(): Probe Conflict detected\n"));
+        autoip_restart(netif);
+      }
+    } else {
+     /* RFC 3927 Section 2.5:
+      * in any state we have a conflict if
+      * ip.src == llipaddr && hw.src != own hwaddr
+      */
+      if (ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr) &&
+          !eth_addr_cmp(&netifaddr, &hdr->shwaddr)) {
+        LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
+          ("autoip_arp_reply(): Conflicting ARP-Packet detected\n"));
+        autoip_handle_arp_conflict(netif);
+      }
+    }
+  }
+}
+
+#endif /* LWIP_AUTOIP */
diff --git a/core/lwip/src/core/ipv4/icmp.c b/core/lwip/src/core/ipv4/icmp.c
new file mode 100644
index 00000000..32902a52
--- /dev/null
+++ b/core/lwip/src/core/ipv4/icmp.c
@@ -0,0 +1,335 @@
+/**
+ * @file
+ * ICMP - Internet Control Message Protocol
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+/* Some ICMP messages should be passed to the transport protocols. This
+   is not implemented. */
+
+#include "lwip/opt.h"
+
+#if LWIP_ICMP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/icmp.h"
+#include "lwip/inet_chksum.h"
+#include "lwip/ip.h"
+#include "lwip/def.h"
+#include "lwip/stats.h"
+#include "lwip/snmp.h"
+
+#include <string.h>
+
+/** Small optimization: set to 0 if incoming PBUF_POOL pbuf always can be
+ * used to modify and send a response packet (and to 1 if this is not the case,
+ * e.g. when link header is stripped of when receiving) */
+#ifndef LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
+#define LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN 1
+#endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
+
+/* The amount of data from the original packet to return in a dest-unreachable */
+#define ICMP_DEST_UNREACH_DATASIZE 8
+
+static void icmp_send_response(struct pbuf *p, u8_t type, u8_t code);
+
+/**
+ * Processes ICMP input packets, called from ip_input().
+ *
+ * Currently only processes icmp echo requests and sends
+ * out the echo response.
+ *
+ * @param p the icmp echo request packet, p->payload pointing to the ip header
+ * @param inp the netif on which this packet was received
+ */
+void
+icmp_input(struct pbuf *p, struct netif *inp)
+{
+  u8_t type;
+#ifdef LWIP_DEBUG
+  u8_t code;
+#endif /* LWIP_DEBUG */
+  struct icmp_echo_hdr *iecho;
+  struct ip_hdr *iphdr;
+  s16_t hlen;
+
+  ICMP_STATS_INC(icmp.recv);
+  snmp_inc_icmpinmsgs();
+
+
+  iphdr = (struct ip_hdr *)p->payload;
+  hlen = IPH_HL(iphdr) * 4;
+  if (pbuf_header(p, -hlen) || (p->tot_len < sizeof(u16_t)*2)) {
+    LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short ICMP (%"U16_F" bytes) received\n", p->tot_len));
+    goto lenerr;
+  }
+
+  type = *((u8_t *)p->payload);
+#ifdef LWIP_DEBUG
+  code = *(((u8_t *)p->payload)+1);
+#endif /* LWIP_DEBUG */
+  switch (type) {
+  case ICMP_ER:
+    /* This is OK, echo reply might have been parsed by a raw PCB
+       (as obviously, an echo request has been sent, too). */
+    break; 
+  case ICMP_ECHO:
+#if !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING
+    {
+      int accepted = 1;
+#if !LWIP_MULTICAST_PING
+      /* multicast destination address? */
+      if (ip_addr_ismulticast(&current_iphdr_dest)) {
+        accepted = 0;
+      }
+#endif /* LWIP_MULTICAST_PING */
+#if !LWIP_BROADCAST_PING
+      /* broadcast destination address? */
+      if (ip_addr_isbroadcast(&current_iphdr_dest, inp)) {
+        accepted = 0;
+      }
+#endif /* LWIP_BROADCAST_PING */
+      /* broadcast or multicast destination address not acceptd? */
+      if (!accepted) {
+        LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to multicast or broadcast pings\n"));
+        ICMP_STATS_INC(icmp.err);
+        pbuf_free(p);
+        return;
+      }
+    }
+#endif /* !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING */
+    LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n"));
+    if (p->tot_len < sizeof(struct icmp_echo_hdr)) {
+      LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n"));
+      goto lenerr;
+    }
+    if (inet_chksum_pbuf(p) != 0) {
+      LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo\n"));
+      pbuf_free(p);
+      ICMP_STATS_INC(icmp.chkerr);
+      snmp_inc_icmpinerrors();
+      return;
+    }
+#if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
+    if (pbuf_header(p, (PBUF_IP_HLEN + PBUF_LINK_HLEN))) {
+      /* p is not big enough to contain link headers
+       * allocate a new one and copy p into it
+       */
+      struct pbuf *r;
+      /* switch p->payload to ip header */
+      if (pbuf_header(p, hlen)) {
+        LWIP_ASSERT("icmp_input: moving p->payload to ip header failed\n", 0);
+        goto memerr;
+      }
+      /* allocate new packet buffer with space for link headers */
+      r = pbuf_alloc(PBUF_LINK, p->tot_len, PBUF_RAM);
+      if (r == NULL) {
+        LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: allocating new pbuf failed\n"));
+        goto memerr;
+      }
+      LWIP_ASSERT("check that first pbuf can hold struct the ICMP header",
+                  (r->len >= hlen + sizeof(struct icmp_echo_hdr)));
+      /* copy the whole packet including ip header */
+      if (pbuf_copy(r, p) != ERR_OK) {
+        LWIP_ASSERT("icmp_input: copying to new pbuf failed\n", 0);
+        goto memerr;
+      }
+      iphdr = (struct ip_hdr *)r->payload;
+      /* switch r->payload back to icmp header */
+      if (pbuf_header(r, -hlen)) {
+        LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0);
+        goto memerr;
+      }
+      /* free the original p */
+      pbuf_free(p);
+      /* we now have an identical copy of p that has room for link headers */
+      p = r;
+    } else {
+      /* restore p->payload to point to icmp header */
+      if (pbuf_header(p, -(s16_t)(PBUF_IP_HLEN + PBUF_LINK_HLEN))) {
+        LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0);
+        goto memerr;
+      }
+    }
+#endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
+    /* At this point, all checks are OK. */
+    /* We generate an answer by switching the dest and src ip addresses,
+     * setting the icmp type to ECHO_RESPONSE and updating the checksum. */
+    iecho = (struct icmp_echo_hdr *)p->payload;
+    ip_addr_copy(iphdr->src, *ip_current_dest_addr());
+    ip_addr_copy(iphdr->dest, *ip_current_src_addr());
+    ICMPH_TYPE_SET(iecho, ICMP_ER);
+    /* adjust the checksum */
+    if (iecho->chksum >= PP_HTONS(0xffffU - (ICMP_ECHO << 8))) {
+      iecho->chksum += PP_HTONS(ICMP_ECHO << 8) + 1;
+    } else {
+      iecho->chksum += PP_HTONS(ICMP_ECHO << 8);
+    }
+
+    /* Set the correct TTL and recalculate the header checksum. */
+    IPH_TTL_SET(iphdr, ICMP_TTL);
+    IPH_CHKSUM_SET(iphdr, 0);
+#if CHECKSUM_GEN_IP
+    IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
+#endif /* CHECKSUM_GEN_IP */
+
+    ICMP_STATS_INC(icmp.xmit);
+    /* increase number of messages attempted to send */
+    snmp_inc_icmpoutmsgs();
+    /* increase number of echo replies attempted to send */
+    snmp_inc_icmpoutechoreps();
+
+    if(pbuf_header(p, hlen)) {
+      LWIP_ASSERT("Can't move over header in packet", 0);
+    } else {
+      err_t ret;
+      /* send an ICMP packet, src addr is the dest addr of the curren packet */
+      ret = ip_output_if(p, ip_current_dest_addr(), IP_HDRINCL,
+                   ICMP_TTL, 0, IP_PROTO_ICMP, inp);
+      if (ret != ERR_OK) {
+        LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ip_output_if returned an error: %c.\n", ret));
+      }
+    }
+    break;
+  default:
+    LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type %"S16_F" code %"S16_F" not supported.\n", 
+                (s16_t)type, (s16_t)code));
+    ICMP_STATS_INC(icmp.proterr);
+    ICMP_STATS_INC(icmp.drop);
+  }
+  pbuf_free(p);
+  return;
+lenerr:
+  pbuf_free(p);
+  ICMP_STATS_INC(icmp.lenerr);
+  snmp_inc_icmpinerrors();
+  return;
+#if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
+memerr:
+  pbuf_free(p);
+  ICMP_STATS_INC(icmp.err);
+  snmp_inc_icmpinerrors();
+  return;
+#endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
+}
+
+/**
+ * Send an icmp 'destination unreachable' packet, called from ip_input() if
+ * the transport layer protocol is unknown and from udp_input() if the local
+ * port is not bound.
+ *
+ * @param p the input packet for which the 'unreachable' should be sent,
+ *          p->payload pointing to the IP header
+ * @param t type of the 'unreachable' packet
+ */
+void
+icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t)
+{
+  icmp_send_response(p, ICMP_DUR, t);
+}
+
+#if IP_FORWARD || IP_REASSEMBLY
+/**
+ * Send a 'time exceeded' packet, called from ip_forward() if TTL is 0.
+ *
+ * @param p the input packet for which the 'time exceeded' should be sent,
+ *          p->payload pointing to the IP header
+ * @param t type of the 'time exceeded' packet
+ */
+void
+icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t)
+{
+  icmp_send_response(p, ICMP_TE, t);
+}
+
+#endif /* IP_FORWARD || IP_REASSEMBLY */
+
+/**
+ * Send an icmp packet in response to an incoming packet.
+ *
+ * @param p the input packet for which the 'unreachable' should be sent,
+ *          p->payload pointing to the IP header
+ * @param type Type of the ICMP header
+ * @param code Code of the ICMP header
+ */
+static void
+icmp_send_response(struct pbuf *p, u8_t type, u8_t code)
+{
+  struct pbuf *q;
+  struct ip_hdr *iphdr;
+  /* we can use the echo header here */
+  struct icmp_echo_hdr *icmphdr;
+  ip_addr_t iphdr_src;
+
+  /* ICMP header + IP header + 8 bytes of data */
+  q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE,
+                 PBUF_RAM);
+  if (q == NULL) {
+    LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded: failed to allocate pbuf for ICMP packet.\n"));
+    return;
+  }
+  LWIP_ASSERT("check that first pbuf can hold icmp message",
+             (q->len >= (sizeof(struct icmp_echo_hdr) + IP_HLEN + ICMP_DEST_UNREACH_DATASIZE)));
+
+  iphdr = (struct ip_hdr *)p->payload;
+  LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded from "));
+  ip_addr_debug_print(ICMP_DEBUG, &(iphdr->src));
+  LWIP_DEBUGF(ICMP_DEBUG, (" to "));
+  ip_addr_debug_print(ICMP_DEBUG, &(iphdr->dest));
+  LWIP_DEBUGF(ICMP_DEBUG, ("\n"));
+
+  icmphdr = (struct icmp_echo_hdr *)q->payload;
+  icmphdr->type = type;
+  icmphdr->code = code;
+  icmphdr->id = 0;
+  icmphdr->seqno = 0;
+
+  /* copy fields from original packet */
+  SMEMCPY((u8_t *)q->payload + sizeof(struct icmp_echo_hdr), (u8_t *)p->payload,
+          IP_HLEN + ICMP_DEST_UNREACH_DATASIZE);
+
+  /* calculate checksum */
+  icmphdr->chksum = 0;
+  icmphdr->chksum = inet_chksum(icmphdr, q->len);
+  ICMP_STATS_INC(icmp.xmit);
+  /* increase number of messages attempted to send */
+  snmp_inc_icmpoutmsgs();
+  /* increase number of destination unreachable messages attempted to send */
+  snmp_inc_icmpouttimeexcds();
+  ip_addr_copy(iphdr_src, iphdr->src);
+  ip_output(q, NULL, &iphdr_src, ICMP_TTL, 0, IP_PROTO_ICMP);
+  pbuf_free(q);
+}
+
+#endif /* LWIP_ICMP */
diff --git a/core/lwip/src/core/ipv4/igmp.c b/core/lwip/src/core/ipv4/igmp.c
new file mode 100644
index 00000000..4e4405e1
--- /dev/null
+++ b/core/lwip/src/core/ipv4/igmp.c
@@ -0,0 +1,817 @@
+/**
+ * @file
+ * IGMP - Internet Group Management Protocol
+ *
+ */
+
+/*
+ * Copyright (c) 2002 CITEL Technologies Ltd.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions 
+ * are met: 
+ * 1. Redistributions of source code must retain the above copyright 
+ *    notice, this list of conditions and the following disclaimer. 
+ * 2. Redistributions in binary form must reproduce the above copyright 
+ *    notice, this list of conditions and the following disclaimer in the 
+ *    documentation and/or other materials provided with the distribution. 
+ * 3. Neither the name of CITEL Technologies Ltd nor the names of its contributors 
+ *    may be used to endorse or promote products derived from this software 
+ *    without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY CITEL TECHNOLOGIES AND CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
+ * ARE DISCLAIMED.  IN NO EVENT SHALL CITEL TECHNOLOGIES OR CONTRIBUTORS BE LIABLE 
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
+ * SUCH DAMAGE. 
+ *
+ * This file is a contribution to the lwIP TCP/IP stack.
+ * The Swedish Institute of Computer Science and Adam Dunkels
+ * are specifically granted permission to redistribute this
+ * source code.
+*/
+
+/*-------------------------------------------------------------
+Note 1)
+Although the rfc requires V1 AND V2 capability
+we will only support v2 since now V1 is very old (August 1989)
+V1 can be added if required
+
+a debug print and statistic have been implemented to
+show this up.
+-------------------------------------------------------------
+-------------------------------------------------------------
+Note 2)
+A query for a specific group address (as opposed to ALLHOSTS)
+has now been implemented as I am unsure if it is required
+
+a debug print and statistic have been implemented to
+show this up.
+-------------------------------------------------------------
+-------------------------------------------------------------
+Note 3)
+The router alert rfc 2113 is implemented in outgoing packets
+but not checked rigorously incoming
+-------------------------------------------------------------
+Steve Reynolds
+------------------------------------------------------------*/
+
+/*-----------------------------------------------------------------------------
+ * RFC 988  - Host extensions for IP multicasting                         - V0
+ * RFC 1054 - Host extensions for IP multicasting                         -
+ * RFC 1112 - Host extensions for IP multicasting                         - V1
+ * RFC 2236 - Internet Group Management Protocol, Version 2               - V2  <- this code is based on this RFC (it's the "de facto" standard)
+ * RFC 3376 - Internet Group Management Protocol, Version 3               - V3
+ * RFC 4604 - Using Internet Group Management Protocol Version 3...       - V3+
+ * RFC 2113 - IP Router Alert Option                                      - 
+ *----------------------------------------------------------------------------*/
+
+/*-----------------------------------------------------------------------------
+ * Includes
+ *----------------------------------------------------------------------------*/
+
+#include "lwip/opt.h"
+
+#if LWIP_IGMP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/igmp.h"
+#include "lwip/debug.h"
+#include "lwip/def.h"
+#include "lwip/mem.h"
+#include "lwip/ip.h"
+#include "lwip/inet_chksum.h"
+#include "lwip/netif.h"
+#include "lwip/icmp.h"
+#include "lwip/udp.h"
+#include "lwip/tcp.h"
+#include "lwip/stats.h"
+
+#include "string.h"
+
+/* 
+ * IGMP constants
+ */
+#define IGMP_TTL                       1
+#define IGMP_MINLEN                    8
+#define ROUTER_ALERT                   0x9404U
+#define ROUTER_ALERTLEN                4
+
+/*
+ * IGMP message types, including version number.
+ */
+#define IGMP_MEMB_QUERY                0x11 /* Membership query         */
+#define IGMP_V1_MEMB_REPORT            0x12 /* Ver. 1 membership report */
+#define IGMP_V2_MEMB_REPORT            0x16 /* Ver. 2 membership report */
+#define IGMP_LEAVE_GROUP               0x17 /* Leave-group message      */
+
+/* Group  membership states */
+#define IGMP_GROUP_NON_MEMBER          0
+#define IGMP_GROUP_DELAYING_MEMBER     1
+#define IGMP_GROUP_IDLE_MEMBER         2
+
+/**
+ * IGMP packet format.
+ */
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct igmp_msg {
+ PACK_STRUCT_FIELD(u8_t           igmp_msgtype);
+ PACK_STRUCT_FIELD(u8_t           igmp_maxresp);
+ PACK_STRUCT_FIELD(u16_t          igmp_checksum);
+ PACK_STRUCT_FIELD(ip_addr_p_t    igmp_group_address);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+
+static struct igmp_group *igmp_lookup_group(struct netif *ifp, ip_addr_t *addr);
+static err_t  igmp_remove_group(struct igmp_group *group);
+static void   igmp_timeout( struct igmp_group *group);
+static void   igmp_start_timer(struct igmp_group *group, u8_t max_time);
+static void   igmp_stop_timer(struct igmp_group *group);
+static void   igmp_delaying_member(struct igmp_group *group, u8_t maxresp);
+static err_t  igmp_ip_output_if(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest, struct netif *netif);
+static void   igmp_send(struct igmp_group *group, u8_t type);
+
+
+static struct igmp_group* igmp_group_list;
+static ip_addr_t     allsystems;
+static ip_addr_t     allrouters;
+
+
+/**
+ * Initialize the IGMP module
+ */
+void
+igmp_init(void)
+{
+  LWIP_DEBUGF(IGMP_DEBUG, ("igmp_init: initializing\n"));
+
+  IP4_ADDR(&allsystems, 224, 0, 0, 1);
+  IP4_ADDR(&allrouters, 224, 0, 0, 2);
+}
+
+#ifdef LWIP_DEBUG
+/**
+ * Dump global IGMP groups list
+ */
+void
+igmp_dump_group_list()
+{ 
+  struct igmp_group *group = igmp_group_list;
+
+  while (group != NULL) {
+    LWIP_DEBUGF(IGMP_DEBUG, ("igmp_dump_group_list: [%"U32_F"] ", (u32_t)(group->group_state)));
+    ip_addr_debug_print(IGMP_DEBUG, &group->group_address);
+    LWIP_DEBUGF(IGMP_DEBUG, (" on if %p\n", group->netif));
+    group = group->next;
+  }
+  LWIP_DEBUGF(IGMP_DEBUG, ("\n"));
+}
+#else
+#define igmp_dump_group_list()
+#endif /* LWIP_DEBUG */
+
+/**
+ * Start IGMP processing on interface
+ *
+ * @param netif network interface on which start IGMP processing
+ */
+err_t
+igmp_start(struct netif *netif)
+{
+  struct igmp_group* group;
+
+  LWIP_DEBUGF(IGMP_DEBUG, ("igmp_start: starting IGMP processing on if %p\n", netif));
+
+  group = igmp_lookup_group(netif, &allsystems);
+
+  if (group != NULL) {
+    group->group_state = IGMP_GROUP_IDLE_MEMBER;
+    group->use++;
+
+    /* Allow the igmp messages at the MAC level */
+    if (netif->igmp_mac_filter != NULL) {
+      LWIP_DEBUGF(IGMP_DEBUG, ("igmp_start: igmp_mac_filter(ADD "));
+      ip_addr_debug_print(IGMP_DEBUG, &allsystems);
+      LWIP_DEBUGF(IGMP_DEBUG, (") on if %p\n", netif));
+      netif->igmp_mac_filter(netif, &allsystems, IGMP_ADD_MAC_FILTER);
+    }
+
+    return ERR_OK;
+  }
+
+  return ERR_MEM;
+}
+
+/**
+ * Stop IGMP processing on interface
+ *
+ * @param netif network interface on which stop IGMP processing
+ */
+err_t
+igmp_stop(struct netif *netif)
+{
+  struct igmp_group *group = igmp_group_list;
+  struct igmp_group *prev  = NULL;
+  struct igmp_group *next;
+
+  /* look for groups joined on this interface further down the list */
+  while (group != NULL) {
+    next = group->next;
+    /* is it a group joined on this interface? */
+    if (group->netif == netif) {
+      /* is it the first group of the list? */
+      if (group == igmp_group_list) {
+        igmp_group_list = next;
+      }
+      /* is there a "previous" group defined? */
+      if (prev != NULL) {
+        prev->next = next;
+      }
+      /* disable the group at the MAC level */
+      if (netif->igmp_mac_filter != NULL) {
+        LWIP_DEBUGF(IGMP_DEBUG, ("igmp_stop: igmp_mac_filter(DEL "));
+        ip_addr_debug_print(IGMP_DEBUG, &group->group_address);
+        LWIP_DEBUGF(IGMP_DEBUG, (") on if %p\n", netif));
+        netif->igmp_mac_filter(netif, &(group->group_address), IGMP_DEL_MAC_FILTER);
+      }
+      /* free group */
+      memp_free(MEMP_IGMP_GROUP, group);
+    } else {
+      /* change the "previous" */
+      prev = group;
+    }
+    /* move to "next" */
+    group = next;
+  }
+  return ERR_OK;
+}
+
+/**
+ * Report IGMP memberships for this interface
+ *
+ * @param netif network interface on which report IGMP memberships
+ */
+void
+igmp_report_groups(struct netif *netif)
+{
+  struct igmp_group *group = igmp_group_list;
+
+  LWIP_DEBUGF(IGMP_DEBUG, ("igmp_report_groups: sending IGMP reports on if %p\n", netif));
+
+  while (group != NULL) {
+    if (group->netif == netif) {
+      igmp_delaying_member(group, IGMP_JOIN_DELAYING_MEMBER_TMR);
+    }
+    group = group->next;
+  }
+}
+
+/**
+ * Search for a group in the global igmp_group_list
+ *
+ * @param ifp the network interface for which to look
+ * @param addr the group ip address to search for
+ * @return a struct igmp_group* if the group has been found,
+ *         NULL if the group wasn't found.
+ */
+struct igmp_group *
+igmp_lookfor_group(struct netif *ifp, ip_addr_t *addr)
+{
+  struct igmp_group *group = igmp_group_list;
+
+  while (group != NULL) {
+    if ((group->netif == ifp) && (ip_addr_cmp(&(group->group_address), addr))) {
+      return group;
+    }
+    group = group->next;
+  }
+
+  /* to be clearer, we return NULL here instead of
+   * 'group' (which is also NULL at this point).
+   */
+  return NULL;
+}
+
+/**
+ * Search for a specific igmp group and create a new one if not found-
+ *
+ * @param ifp the network interface for which to look
+ * @param addr the group ip address to search
+ * @return a struct igmp_group*,
+ *         NULL on memory error.
+ */
+struct igmp_group *
+igmp_lookup_group(struct netif *ifp, ip_addr_t *addr)
+{
+  struct igmp_group *group = igmp_group_list;
+  
+  /* Search if the group already exists */
+  group = igmp_lookfor_group(ifp, addr);
+  if (group != NULL) {
+    /* Group already exists. */
+    return group;
+  }
+
+  /* Group doesn't exist yet, create a new one */
+  group = (struct igmp_group *)memp_malloc(MEMP_IGMP_GROUP);
+  if (group != NULL) {
+    group->netif              = ifp;
+    ip_addr_set(&(group->group_address), addr);
+    group->timer              = 0; /* Not running */
+    group->group_state        = IGMP_GROUP_NON_MEMBER;
+    group->last_reporter_flag = 0;
+    group->use                = 0;
+    group->next               = igmp_group_list;
+    
+    igmp_group_list = group;
+  }
+
+  LWIP_DEBUGF(IGMP_DEBUG, ("igmp_lookup_group: %sallocated a new group with address ", (group?"":"impossible to ")));
+  ip_addr_debug_print(IGMP_DEBUG, addr);
+  LWIP_DEBUGF(IGMP_DEBUG, (" on if %p\n", ifp));
+
+  return group;
+}
+
+/**
+ * Remove a group in the global igmp_group_list
+ *
+ * @param group the group to remove from the global igmp_group_list
+ * @return ERR_OK if group was removed from the list, an err_t otherwise
+ */
+static err_t
+igmp_remove_group(struct igmp_group *group)
+{
+  err_t err = ERR_OK;
+
+  /* Is it the first group? */
+  if (igmp_group_list == group) {
+    igmp_group_list = group->next;
+  } else {
+    /* look for group further down the list */
+    struct igmp_group *tmpGroup;
+    for (tmpGroup = igmp_group_list; tmpGroup != NULL; tmpGroup = tmpGroup->next) {
+      if (tmpGroup->next == group) {
+        tmpGroup->next = group->next;
+        break;
+      }
+    }
+    /* Group not found in the global igmp_group_list */
+    if (tmpGroup == NULL)
+      err = ERR_ARG;
+  }
+  /* free group */
+  memp_free(MEMP_IGMP_GROUP, group);
+
+  return err;
+}
+
+/**
+ * Called from ip_input() if a new IGMP packet is received.
+ *
+ * @param p received igmp packet, p->payload pointing to the ip header
+ * @param inp network interface on which the packet was received
+ * @param dest destination ip address of the igmp packet
+ */
+void
+igmp_input(struct pbuf *p, struct netif *inp, ip_addr_t *dest)
+{
+  struct ip_hdr *    iphdr;
+  struct igmp_msg*   igmp;
+  struct igmp_group* group;
+  struct igmp_group* groupref;
+
+  IGMP_STATS_INC(igmp.recv);
+
+  /* Note that the length CAN be greater than 8 but only 8 are used - All are included in the checksum */    
+  iphdr = (struct ip_hdr *)p->payload;
+  if (pbuf_header(p, -(s16_t)(IPH_HL(iphdr) * 4)) || (p->len < IGMP_MINLEN)) {
+    pbuf_free(p);
+    IGMP_STATS_INC(igmp.lenerr);
+    LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: length error\n"));
+    return;
+  }
+
+  LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: message from "));
+  ip_addr_debug_print(IGMP_DEBUG, &(iphdr->src));
+  LWIP_DEBUGF(IGMP_DEBUG, (" to address "));
+  ip_addr_debug_print(IGMP_DEBUG, &(iphdr->dest));
+  LWIP_DEBUGF(IGMP_DEBUG, (" on if %p\n", inp));
+
+  /* Now calculate and check the checksum */
+  igmp = (struct igmp_msg *)p->payload;
+  if (inet_chksum(igmp, p->len)) {
+    pbuf_free(p);
+    IGMP_STATS_INC(igmp.chkerr);
+    LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: checksum error\n"));
+    return;
+  }
+
+  /* Packet is ok so find an existing group */
+  group = igmp_lookfor_group(inp, dest); /* use the destination IP address of incoming packet */
+  
+  /* If group can be found or create... */
+  if (!group) {
+    pbuf_free(p);
+    IGMP_STATS_INC(igmp.drop);
+    LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: IGMP frame not for us\n"));
+    return;
+  }
+
+  /* NOW ACT ON THE INCOMING MESSAGE TYPE... */
+  switch (igmp->igmp_msgtype) {
+   case IGMP_MEMB_QUERY: {
+     /* IGMP_MEMB_QUERY to the "all systems" address ? */
+     if ((ip_addr_cmp(dest, &allsystems)) && ip_addr_isany(&igmp->igmp_group_address)) {
+       /* THIS IS THE GENERAL QUERY */
+       LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: General IGMP_MEMB_QUERY on \"ALL SYSTEMS\" address (224.0.0.1) [igmp_maxresp=%i]\n", (int)(igmp->igmp_maxresp)));
+
+       if (igmp->igmp_maxresp == 0) {
+         IGMP_STATS_INC(igmp.rx_v1);
+         LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: got an all hosts query with time== 0 - this is V1 and not implemented - treat as v2\n"));
+         igmp->igmp_maxresp = IGMP_V1_DELAYING_MEMBER_TMR;
+       } else {
+         IGMP_STATS_INC(igmp.rx_general);
+       }
+
+       groupref = igmp_group_list;
+       while (groupref) {
+         /* Do not send messages on the all systems group address! */
+         if ((groupref->netif == inp) && (!(ip_addr_cmp(&(groupref->group_address), &allsystems)))) {
+           igmp_delaying_member(groupref, igmp->igmp_maxresp);
+         }
+         groupref = groupref->next;
+       }
+     } else {
+       /* IGMP_MEMB_QUERY to a specific group ? */
+       if (!ip_addr_isany(&igmp->igmp_group_address)) {
+         LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: IGMP_MEMB_QUERY to a specific group "));
+         ip_addr_debug_print(IGMP_DEBUG, &igmp->igmp_group_address);
+         if (ip_addr_cmp(dest, &allsystems)) {
+           ip_addr_t groupaddr;
+           LWIP_DEBUGF(IGMP_DEBUG, (" using \"ALL SYSTEMS\" address (224.0.0.1) [igmp_maxresp=%i]\n", (int)(igmp->igmp_maxresp)));
+           /* we first need to re-look for the group since we used dest last time */
+           ip_addr_copy(groupaddr, igmp->igmp_group_address);
+           group = igmp_lookfor_group(inp, &groupaddr);
+         } else {
+           LWIP_DEBUGF(IGMP_DEBUG, (" with the group address as destination [igmp_maxresp=%i]\n", (int)(igmp->igmp_maxresp)));
+         }
+
+         if (group != NULL) {
+           IGMP_STATS_INC(igmp.rx_group);
+           igmp_delaying_member(group, igmp->igmp_maxresp);
+         } else {
+           IGMP_STATS_INC(igmp.drop);
+         }
+       } else {
+         IGMP_STATS_INC(igmp.proterr);
+       }
+     }
+     break;
+   }
+   case IGMP_V2_MEMB_REPORT: {
+     LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: IGMP_V2_MEMB_REPORT\n"));
+     IGMP_STATS_INC(igmp.rx_report);
+     if (group->group_state == IGMP_GROUP_DELAYING_MEMBER) {
+       /* This is on a specific group we have already looked up */
+       group->timer = 0; /* stopped */
+       group->group_state = IGMP_GROUP_IDLE_MEMBER;
+       group->last_reporter_flag = 0;
+     }
+     break;
+   }
+   default: {
+     LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: unexpected msg %d in state %d on group %p on if %p\n",
+       igmp->igmp_msgtype, group->group_state, &group, group->netif));
+     IGMP_STATS_INC(igmp.proterr);
+     break;
+   }
+  }
+
+  pbuf_free(p);
+  return;
+}
+
+/**
+ * Join a group on one network interface.
+ *
+ * @param ifaddr ip address of the network interface which should join a new group
+ * @param groupaddr the ip address of the group which to join
+ * @return ERR_OK if group was joined on the netif(s), an err_t otherwise
+ */
+err_t
+igmp_joingroup(ip_addr_t *ifaddr, ip_addr_t *groupaddr)
+{
+  err_t              err = ERR_VAL; /* no matching interface */
+  struct igmp_group *group;
+  struct netif      *netif;
+
+  /* make sure it is multicast address */
+  LWIP_ERROR("igmp_joingroup: attempt to join non-multicast address", ip_addr_ismulticast(groupaddr), return ERR_VAL;);
+  LWIP_ERROR("igmp_joingroup: attempt to join allsystems address", (!ip_addr_cmp(groupaddr, &allsystems)), return ERR_VAL;);
+
+  /* loop through netif's */
+  netif = netif_list;
+  while (netif != NULL) {
+    /* Should we join this interface ? */
+    if ((netif->flags & NETIF_FLAG_IGMP) && ((ip_addr_isany(ifaddr) || ip_addr_cmp(&(netif->ip_addr), ifaddr)))) {
+      /* find group or create a new one if not found */
+      group = igmp_lookup_group(netif, groupaddr);
+
+      if (group != NULL) {
+        /* This should create a new group, check the state to make sure */
+        if (group->group_state != IGMP_GROUP_NON_MEMBER) {
+          LWIP_DEBUGF(IGMP_DEBUG, ("igmp_joingroup: join to group not in state IGMP_GROUP_NON_MEMBER\n"));
+        } else {
+          /* OK - it was new group */
+          LWIP_DEBUGF(IGMP_DEBUG, ("igmp_joingroup: join to new group: "));
+          ip_addr_debug_print(IGMP_DEBUG, groupaddr);
+          LWIP_DEBUGF(IGMP_DEBUG, ("\n"));
+
+          /* If first use of the group, allow the group at the MAC level */
+          if ((group->use==0) && (netif->igmp_mac_filter != NULL)) {
+            LWIP_DEBUGF(IGMP_DEBUG, ("igmp_joingroup: igmp_mac_filter(ADD "));
+            ip_addr_debug_print(IGMP_DEBUG, groupaddr);
+            LWIP_DEBUGF(IGMP_DEBUG, (") on if %p\n", netif));
+            netif->igmp_mac_filter(netif, groupaddr, IGMP_ADD_MAC_FILTER);
+          }
+
+          IGMP_STATS_INC(igmp.tx_join);
+          igmp_send(group, IGMP_V2_MEMB_REPORT);
+
+          igmp_start_timer(group, IGMP_JOIN_DELAYING_MEMBER_TMR);
+
+          /* Need to work out where this timer comes from */
+          group->group_state = IGMP_GROUP_DELAYING_MEMBER;
+        }
+        /* Increment group use */
+        group->use++;
+        /* Join on this interface */
+        err = ERR_OK;
+      } else {
+        /* Return an error even if some network interfaces are joined */
+        /** @todo undo any other netif already joined */
+        LWIP_DEBUGF(IGMP_DEBUG, ("igmp_joingroup: Not enought memory to join to group\n"));
+        return ERR_MEM;
+      }
+    }
+    /* proceed to next network interface */
+    netif = netif->next;
+  }
+
+  return err;
+}
+
+/**
+ * Leave a group on one network interface.
+ *
+ * @param ifaddr ip address of the network interface which should leave a group
+ * @param groupaddr the ip address of the group which to leave
+ * @return ERR_OK if group was left on the netif(s), an err_t otherwise
+ */
+err_t
+igmp_leavegroup(ip_addr_t *ifaddr, ip_addr_t *groupaddr)
+{
+  err_t              err = ERR_VAL; /* no matching interface */
+  struct igmp_group *group;
+  struct netif      *netif;
+
+  /* make sure it is multicast address */
+  LWIP_ERROR("igmp_leavegroup: attempt to leave non-multicast address", ip_addr_ismulticast(groupaddr), return ERR_VAL;);
+  LWIP_ERROR("igmp_leavegroup: attempt to leave allsystems address", (!ip_addr_cmp(groupaddr, &allsystems)), return ERR_VAL;);
+
+  /* loop through netif's */
+  netif = netif_list;
+  while (netif != NULL) {
+    /* Should we leave this interface ? */
+    if ((netif->flags & NETIF_FLAG_IGMP) && ((ip_addr_isany(ifaddr) || ip_addr_cmp(&(netif->ip_addr), ifaddr)))) {
+      /* find group */
+      group = igmp_lookfor_group(netif, groupaddr);
+
+      if (group != NULL) {
+        /* Only send a leave if the flag is set according to the state diagram */
+        LWIP_DEBUGF(IGMP_DEBUG, ("igmp_leavegroup: Leaving group: "));
+        ip_addr_debug_print(IGMP_DEBUG, groupaddr);
+        LWIP_DEBUGF(IGMP_DEBUG, ("\n"));
+
+        /* If there is no other use of the group */
+        if (group->use <= 1) {
+          /* If we are the last reporter for this group */
+          if (group->last_reporter_flag) {
+            LWIP_DEBUGF(IGMP_DEBUG, ("igmp_leavegroup: sending leaving group\n"));
+            IGMP_STATS_INC(igmp.tx_leave);
+            igmp_send(group, IGMP_LEAVE_GROUP);
+          }
+          
+          /* Disable the group at the MAC level */
+          if (netif->igmp_mac_filter != NULL) {
+            LWIP_DEBUGF(IGMP_DEBUG, ("igmp_leavegroup: igmp_mac_filter(DEL "));
+            ip_addr_debug_print(IGMP_DEBUG, groupaddr);
+            LWIP_DEBUGF(IGMP_DEBUG, (") on if %p\n", netif));
+            netif->igmp_mac_filter(netif, groupaddr, IGMP_DEL_MAC_FILTER);
+          }
+          
+          LWIP_DEBUGF(IGMP_DEBUG, ("igmp_leavegroup: remove group: "));
+          ip_addr_debug_print(IGMP_DEBUG, groupaddr);
+          LWIP_DEBUGF(IGMP_DEBUG, ("\n"));          
+          
+          /* Free the group */
+          igmp_remove_group(group);
+        } else {
+          /* Decrement group use */
+          group->use--;
+        }
+        /* Leave on this interface */
+        err = ERR_OK;
+      } else {
+        /* It's not a fatal error on "leavegroup" */
+        LWIP_DEBUGF(IGMP_DEBUG, ("igmp_leavegroup: not member of group\n"));
+      }
+    }
+    /* proceed to next network interface */
+    netif = netif->next;
+  }
+
+  return err;
+}
+
+/**
+ * The igmp timer function (both for NO_SYS=1 and =0)
+ * Should be called every IGMP_TMR_INTERVAL milliseconds (100 ms is default).
+ */
+void
+igmp_tmr(void)
+{
+  struct igmp_group *group = igmp_group_list;
+
+  while (group != NULL) {
+    if (group->timer > 0) {
+      group->timer--;
+      if (group->timer == 0) {
+        igmp_timeout(group);
+      }
+    }
+    group = group->next;
+  }
+}
+
+/**
+ * Called if a timeout for one group is reached.
+ * Sends a report for this group.
+ *
+ * @param group an igmp_group for which a timeout is reached
+ */
+static void
+igmp_timeout(struct igmp_group *group)
+{
+  /* If the state is IGMP_GROUP_DELAYING_MEMBER then we send a report for this group */
+  if (group->group_state == IGMP_GROUP_DELAYING_MEMBER) {
+    LWIP_DEBUGF(IGMP_DEBUG, ("igmp_timeout: report membership for group with address "));
+    ip_addr_debug_print(IGMP_DEBUG, &(group->group_address));
+    LWIP_DEBUGF(IGMP_DEBUG, (" on if %p\n", group->netif));
+
+    IGMP_STATS_INC(igmp.tx_report);
+    igmp_send(group, IGMP_V2_MEMB_REPORT);
+  }
+}
+
+/**
+ * Start a timer for an igmp group
+ *
+ * @param group the igmp_group for which to start a timer
+ * @param max_time the time in multiples of IGMP_TMR_INTERVAL (decrease with
+ *        every call to igmp_tmr())
+ */
+static void
+igmp_start_timer(struct igmp_group *group, u8_t max_time)
+{
+  /* ensure the input value is > 0 */
+  if (max_time == 0) {
+    max_time = 1;
+  }
+  /* ensure the random value is > 0 */
+  group->timer = (LWIP_RAND() % (max_time - 1)) + 1;
+}
+
+/**
+ * Stop a timer for an igmp_group
+ *
+ * @param group the igmp_group for which to stop the timer
+ */
+static void
+igmp_stop_timer(struct igmp_group *group)
+{
+  group->timer = 0;
+}
+
+/**
+ * Delaying membership report for a group if necessary
+ *
+ * @param group the igmp_group for which "delaying" membership report
+ * @param maxresp query delay
+ */
+static void
+igmp_delaying_member(struct igmp_group *group, u8_t maxresp)
+{
+  if ((group->group_state == IGMP_GROUP_IDLE_MEMBER) ||
+     ((group->group_state == IGMP_GROUP_DELAYING_MEMBER) &&
+      ((group->timer == 0) || (maxresp < group->timer)))) {
+    igmp_start_timer(group, maxresp);
+    group->group_state = IGMP_GROUP_DELAYING_MEMBER;
+  }
+}
+
+
+/**
+ * Sends an IP packet on a network interface. This function constructs the IP header
+ * and calculates the IP header checksum. If the source IP address is NULL,
+ * the IP address of the outgoing network interface is filled in as source address.
+ *
+ * @param p the packet to send (p->payload points to the data, e.g. next
+            protocol header; if dest == IP_HDRINCL, p already includes an IP
+            header and p->payload points to that IP header)
+ * @param src the source IP address to send from (if src == IP_ADDR_ANY, the
+ *         IP  address of the netif used to send is used as source address)
+ * @param dest the destination IP address to send the packet to
+ * @param ttl the TTL value to be set in the IP header
+ * @param proto the PROTOCOL to be set in the IP header
+ * @param netif the netif on which to send this packet
+ * @return ERR_OK if the packet was sent OK
+ *         ERR_BUF if p doesn't have enough space for IP/LINK headers
+ *         returns errors returned by netif->output
+ */
+static err_t
+igmp_ip_output_if(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest, struct netif *netif)
+{
+  /* This is the "router alert" option */
+  u16_t ra[2];
+  ra[0] = PP_HTONS(ROUTER_ALERT);
+  ra[1] = 0x0000; /* Router shall examine packet */
+  IGMP_STATS_INC(igmp.xmit);
+  return ip_output_if_opt(p, src, dest, IGMP_TTL, 0, IP_PROTO_IGMP, netif, ra, ROUTER_ALERTLEN);
+}
+
+/**
+ * Send an igmp packet to a specific group.
+ *
+ * @param group the group to which to send the packet
+ * @param type the type of igmp packet to send
+ */
+static void
+igmp_send(struct igmp_group *group, u8_t type)
+{
+  struct pbuf*     p    = NULL;
+  struct igmp_msg* igmp = NULL;
+  ip_addr_t   src  = *IP_ADDR_ANY;
+  ip_addr_t*  dest = NULL;
+
+  /* IP header + "router alert" option + IGMP header */
+  p = pbuf_alloc(PBUF_TRANSPORT, IGMP_MINLEN, PBUF_RAM);
+  
+  if (p) {
+    igmp = (struct igmp_msg *)p->payload;
+    LWIP_ASSERT("igmp_send: check that first pbuf can hold struct igmp_msg",
+               (p->len >= sizeof(struct igmp_msg)));
+    ip_addr_copy(src, group->netif->ip_addr);
+     
+    if (type == IGMP_V2_MEMB_REPORT) {
+      dest = &(group->group_address);
+      ip_addr_copy(igmp->igmp_group_address, group->group_address);
+      group->last_reporter_flag = 1; /* Remember we were the last to report */
+    } else {
+      if (type == IGMP_LEAVE_GROUP) {
+        dest = &allrouters;
+        ip_addr_copy(igmp->igmp_group_address, group->group_address);
+      }
+    }
+
+    if ((type == IGMP_V2_MEMB_REPORT) || (type == IGMP_LEAVE_GROUP)) {
+      igmp->igmp_msgtype  = type;
+      igmp->igmp_maxresp  = 0;
+      igmp->igmp_checksum = 0;
+      igmp->igmp_checksum = inet_chksum(igmp, IGMP_MINLEN);
+
+      igmp_ip_output_if(p, &src, dest, group->netif);
+    }
+
+    pbuf_free(p);
+  } else {
+    LWIP_DEBUGF(IGMP_DEBUG, ("igmp_send: not enough memory for igmp_send\n"));
+    IGMP_STATS_INC(igmp.memerr);
+  }
+}
+
+#endif /* LWIP_IGMP */
diff --git a/core/lwip/src/core/ipv4/inet.c b/core/lwip/src/core/ipv4/inet.c
new file mode 100644
index 00000000..e283a576
--- /dev/null
+++ b/core/lwip/src/core/ipv4/inet.c
@@ -0,0 +1,42 @@
+/**
+ * @file
+ * Functions common to all TCP/IPv4 modules, such as the byte order functions.
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#include "lwip/inet.h"
+
diff --git a/core/lwip/src/core/ipv4/inet_chksum.c b/core/lwip/src/core/ipv4/inet_chksum.c
new file mode 100644
index 00000000..960252f6
--- /dev/null
+++ b/core/lwip/src/core/ipv4/inet_chksum.c
@@ -0,0 +1,450 @@
+/**
+ * @file
+ * Incluse internet checksum functions.
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#include "lwip/inet_chksum.h"
+#include "lwip/def.h"
+
+#include <stddef.h>
+#include <string.h>
+
+/* These are some reference implementations of the checksum algorithm, with the
+ * aim of being simple, correct and fully portable. Checksumming is the
+ * first thing you would want to optimize for your platform. If you create
+ * your own version, link it in and in your cc.h put:
+ * 
+ * #define LWIP_CHKSUM <your_checksum_routine> 
+ *
+ * Or you can select from the implementations below by defining
+ * LWIP_CHKSUM_ALGORITHM to 1, 2 or 3.
+ */
+
+#ifndef LWIP_CHKSUM
+# define LWIP_CHKSUM lwip_standard_chksum
+# ifndef LWIP_CHKSUM_ALGORITHM
+#  define LWIP_CHKSUM_ALGORITHM 2
+# endif
+#endif
+/* If none set: */
+#ifndef LWIP_CHKSUM_ALGORITHM
+# define LWIP_CHKSUM_ALGORITHM 0
+#endif
+
+#if (LWIP_CHKSUM_ALGORITHM == 1) /* Version #1 */
+/**
+ * lwip checksum
+ *
+ * @param dataptr points to start of data to be summed at any boundary
+ * @param len length of data to be summed
+ * @return host order (!) lwip checksum (non-inverted Internet sum) 
+ *
+ * @note accumulator size limits summable length to 64k
+ * @note host endianess is irrelevant (p3 RFC1071)
+ */
+static u16_t
+lwip_standard_chksum(void *dataptr, u16_t len)
+{
+  u32_t acc;
+  u16_t src;
+  u8_t *octetptr;
+
+  acc = 0;
+  /* dataptr may be at odd or even addresses */
+  octetptr = (u8_t*)dataptr;
+  while (len > 1) {
+    /* declare first octet as most significant
+       thus assume network order, ignoring host order */
+    src = (*octetptr) << 8;
+    octetptr++;
+    /* declare second octet as least significant */
+    src |= (*octetptr);
+    octetptr++;
+    acc += src;
+    len -= 2;
+  }
+  if (len > 0) {
+    /* accumulate remaining octet */
+    src = (*octetptr) << 8;
+    acc += src;
+  }
+  /* add deferred carry bits */
+  acc = (acc >> 16) + (acc & 0x0000ffffUL);
+  if ((acc & 0xffff0000UL) != 0) {
+    acc = (acc >> 16) + (acc & 0x0000ffffUL);
+  }
+  /* This maybe a little confusing: reorder sum using htons()
+     instead of ntohs() since it has a little less call overhead.
+     The caller must invert bits for Internet sum ! */
+  return htons((u16_t)acc);
+}
+#endif
+
+#if (LWIP_CHKSUM_ALGORITHM == 2) /* Alternative version #2 */
+/*
+ * Curt McDowell
+ * Broadcom Corp.
+ * csm@broadcom.com
+ *
+ * IP checksum two bytes at a time with support for
+ * unaligned buffer.
+ * Works for len up to and including 0x20000.
+ * by Curt McDowell, Broadcom Corp. 12/08/2005
+ *
+ * @param dataptr points to start of data to be summed at any boundary
+ * @param len length of data to be summed
+ * @return host order (!) lwip checksum (non-inverted Internet sum) 
+ */
+
+static u16_t
+lwip_standard_chksum(void *dataptr, int len)
+{
+  u8_t *pb = (u8_t *)dataptr;
+  u16_t *ps, t = 0;
+  u32_t sum = 0;
+  int odd = ((mem_ptr_t)pb & 1);
+
+  /* Get aligned to u16_t */
+  if (odd && len > 0) {
+    ((u8_t *)&t)[1] = *pb++;
+    len--;
+  }
+
+  /* Add the bulk of the data */
+  ps = (u16_t *)(void *)pb;
+  while (len > 1) {
+    sum += *ps++;
+    len -= 2;
+  }
+
+  /* Consume left-over byte, if any */
+  if (len > 0) {
+    ((u8_t *)&t)[0] = *(u8_t *)ps;
+  }
+
+  /* Add end bytes */
+  sum += t;
+
+  /* Fold 32-bit sum to 16 bits
+     calling this twice is propably faster than if statements... */
+  sum = FOLD_U32T(sum);
+  sum = FOLD_U32T(sum);
+
+  /* Swap if alignment was odd */
+  if (odd) {
+    sum = SWAP_BYTES_IN_WORD(sum);
+  }
+
+  return (u16_t)sum;
+}
+#endif
+
+#if (LWIP_CHKSUM_ALGORITHM == 3) /* Alternative version #3 */
+/**
+ * An optimized checksum routine. Basically, it uses loop-unrolling on
+ * the checksum loop, treating the head and tail bytes specially, whereas
+ * the inner loop acts on 8 bytes at a time. 
+ *
+ * @arg start of buffer to be checksummed. May be an odd byte address.
+ * @len number of bytes in the buffer to be checksummed.
+ * @return host order (!) lwip checksum (non-inverted Internet sum) 
+ * 
+ * by Curt McDowell, Broadcom Corp. December 8th, 2005
+ */
+
+static u16_t
+lwip_standard_chksum(void *dataptr, int len)
+{
+  u8_t *pb = (u8_t *)dataptr;
+  u16_t *ps, t = 0;
+  u32_t *pl;
+  u32_t sum = 0, tmp;
+  /* starts at odd byte address? */
+  int odd = ((mem_ptr_t)pb & 1);
+
+  if (odd && len > 0) {
+    ((u8_t *)&t)[1] = *pb++;
+    len--;
+  }
+
+  ps = (u16_t *)pb;
+
+  if (((mem_ptr_t)ps & 3) && len > 1) {
+    sum += *ps++;
+    len -= 2;
+  }
+
+  pl = (u32_t *)ps;
+
+  while (len > 7)  {
+    tmp = sum + *pl++;          /* ping */
+    if (tmp < sum) {
+      tmp++;                    /* add back carry */
+    }
+
+    sum = tmp + *pl++;          /* pong */
+    if (sum < tmp) {
+      sum++;                    /* add back carry */
+    }
+
+    len -= 8;
+  }
+
+  /* make room in upper bits */
+  sum = FOLD_U32T(sum);
+
+  ps = (u16_t *)pl;
+
+  /* 16-bit aligned word remaining? */
+  while (len > 1) {
+    sum += *ps++;
+    len -= 2;
+  }
+
+  /* dangling tail byte remaining? */
+  if (len > 0) {                /* include odd byte */
+    ((u8_t *)&t)[0] = *(u8_t *)ps;
+  }
+
+  sum += t;                     /* add end bytes */
+
+  /* Fold 32-bit sum to 16 bits
+     calling this twice is propably faster than if statements... */
+  sum = FOLD_U32T(sum);
+  sum = FOLD_U32T(sum);
+
+  if (odd) {
+    sum = SWAP_BYTES_IN_WORD(sum);
+  }
+
+  return (u16_t)sum;
+}
+#endif
+
+/* inet_chksum_pseudo:
+ *
+ * Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain.
+ * IP addresses are expected to be in network byte order.
+ *
+ * @param p chain of pbufs over that a checksum should be calculated (ip data part)
+ * @param src source ip address (used for checksum of pseudo header)
+ * @param dst destination ip address (used for checksum of pseudo header)
+ * @param proto ip protocol (used for checksum of pseudo header)
+ * @param proto_len length of the ip data part (used for checksum of pseudo header)
+ * @return checksum (as u16_t) to be saved directly in the protocol header
+ */
+u16_t
+inet_chksum_pseudo(struct pbuf *p,
+       ip_addr_t *src, ip_addr_t *dest,
+       u8_t proto, u16_t proto_len)
+{
+  u32_t acc;
+  u32_t addr;
+  struct pbuf *q;
+  u8_t swapped;
+
+  acc = 0;
+  swapped = 0;
+  /* iterate through all pbuf in chain */
+  for(q = p; q != NULL; q = q->next) {
+    LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): checksumming pbuf %p (has next %p) \n",
+      (void *)q, (void *)q->next));
+    acc += LWIP_CHKSUM(q->payload, q->len);
+    /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): unwrapped lwip_chksum()=%"X32_F" \n", acc));*/
+    /* just executing this next line is probably faster that the if statement needed
+       to check whether we really need to execute it, and does no harm */
+    acc = FOLD_U32T(acc);
+    if (q->len % 2 != 0) {
+      swapped = 1 - swapped;
+      acc = SWAP_BYTES_IN_WORD(acc);
+    }
+    /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): wrapped lwip_chksum()=%"X32_F" \n", acc));*/
+  }
+
+  if (swapped) {
+    acc = SWAP_BYTES_IN_WORD(acc);
+  }
+  addr = ip4_addr_get_u32(src);
+  acc += (addr & 0xffffUL);
+  acc += ((addr >> 16) & 0xffffUL);
+  addr = ip4_addr_get_u32(dest);
+  acc += (addr & 0xffffUL);
+  acc += ((addr >> 16) & 0xffffUL);
+  acc += (u32_t)htons((u16_t)proto);
+  acc += (u32_t)htons(proto_len);
+
+  /* Fold 32-bit sum to 16 bits
+     calling this twice is propably faster than if statements... */
+  acc = FOLD_U32T(acc);
+  acc = FOLD_U32T(acc);
+  LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): pbuf chain lwip_chksum()=%"X32_F"\n", acc));
+  return (u16_t)~(acc & 0xffffUL);
+}
+
+/* inet_chksum_pseudo:
+ *
+ * Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain.
+ * IP addresses are expected to be in network byte order.
+ *
+ * @param p chain of pbufs over that a checksum should be calculated (ip data part)
+ * @param src source ip address (used for checksum of pseudo header)
+ * @param dst destination ip address (used for checksum of pseudo header)
+ * @param proto ip protocol (used for checksum of pseudo header)
+ * @param proto_len length of the ip data part (used for checksum of pseudo header)
+ * @return checksum (as u16_t) to be saved directly in the protocol header
+ */
+u16_t
+inet_chksum_pseudo_partial(struct pbuf *p,
+       ip_addr_t *src, ip_addr_t *dest,
+       u8_t proto, u16_t proto_len, u16_t chksum_len)
+{
+  u32_t acc;
+  u32_t addr;
+  struct pbuf *q;
+  u8_t swapped;
+  u16_t chklen;
+
+  acc = 0;
+  swapped = 0;
+  /* iterate through all pbuf in chain */
+  for(q = p; (q != NULL) && (chksum_len > 0); q = q->next) {
+    LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): checksumming pbuf %p (has next %p) \n",
+      (void *)q, (void *)q->next));
+    chklen = q->len;
+    if (chklen > chksum_len) {
+      chklen = chksum_len;
+    }
+    acc += LWIP_CHKSUM(q->payload, chklen);
+    chksum_len -= chklen;
+    LWIP_ASSERT("delete me", chksum_len < 0x7fff);
+    /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): unwrapped lwip_chksum()=%"X32_F" \n", acc));*/
+    /* fold the upper bit down */
+    acc = FOLD_U32T(acc);
+    if (q->len % 2 != 0) {
+      swapped = 1 - swapped;
+      acc = SWAP_BYTES_IN_WORD(acc);
+    }
+    /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): wrapped lwip_chksum()=%"X32_F" \n", acc));*/
+  }
+
+  if (swapped) {
+    acc = SWAP_BYTES_IN_WORD(acc);
+  }
+  addr = ip4_addr_get_u32(src);
+  acc += (addr & 0xffffUL);
+  acc += ((addr >> 16) & 0xffffUL);
+  addr = ip4_addr_get_u32(dest);
+  acc += (addr & 0xffffUL);
+  acc += ((addr >> 16) & 0xffffUL);
+  acc += (u32_t)htons((u16_t)proto);
+  acc += (u32_t)htons(proto_len);
+
+  /* Fold 32-bit sum to 16 bits
+     calling this twice is propably faster than if statements... */
+  acc = FOLD_U32T(acc);
+  acc = FOLD_U32T(acc);
+  LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): pbuf chain lwip_chksum()=%"X32_F"\n", acc));
+  return (u16_t)~(acc & 0xffffUL);
+}
+
+/* inet_chksum:
+ *
+ * Calculates the Internet checksum over a portion of memory. Used primarily for IP
+ * and ICMP.
+ *
+ * @param dataptr start of the buffer to calculate the checksum (no alignment needed)
+ * @param len length of the buffer to calculate the checksum
+ * @return checksum (as u16_t) to be saved directly in the protocol header
+ */
+
+u16_t
+inet_chksum(void *dataptr, u16_t len)
+{
+  return ~LWIP_CHKSUM(dataptr, len);
+}
+
+/**
+ * Calculate a checksum over a chain of pbufs (without pseudo-header, much like
+ * inet_chksum only pbufs are used).
+ *
+ * @param p pbuf chain over that the checksum should be calculated
+ * @return checksum (as u16_t) to be saved directly in the protocol header
+ */
+u16_t
+inet_chksum_pbuf(struct pbuf *p)
+{
+  u32_t acc;
+  struct pbuf *q;
+  u8_t swapped;
+
+  acc = 0;
+  swapped = 0;
+  for(q = p; q != NULL; q = q->next) {
+    acc += LWIP_CHKSUM(q->payload, q->len);
+    acc = FOLD_U32T(acc);
+    if (q->len % 2 != 0) {
+      swapped = 1 - swapped;
+      acc = SWAP_BYTES_IN_WORD(acc);
+    }
+  }
+
+  if (swapped) {
+    acc = SWAP_BYTES_IN_WORD(acc);
+  }
+  return (u16_t)~(acc & 0xffffUL);
+}
+
+/* These are some implementations for LWIP_CHKSUM_COPY, which copies data
+ * like MEMCPY but generates a checksum at the same time. Since this is a
+ * performance-sensitive function, you might want to create your own version
+ * in assembly targeted at your hardware by defining it in lwipopts.h:
+ *   #define LWIP_CHKSUM_COPY(dst, src, len) your_chksum_copy(dst, src, len)
+ */
+
+#if (LWIP_CHKSUM_COPY_ALGORITHM == 1) /* Version #1 */
+/** Safe but slow: first call MEMCPY, then call LWIP_CHKSUM.
+ * For architectures with big caches, data might still be in cache when
+ * generating the checksum after copying.
+ */
+u16_t
+lwip_chksum_copy(void *dst, const void *src, u16_t len)
+{
+  MEMCPY(dst, src, len);
+  return LWIP_CHKSUM(dst, len);
+}
+#endif /* (LWIP_CHKSUM_COPY_ALGORITHM == 1) */
diff --git a/core/lwip/src/core/ipv4/ip.c b/core/lwip/src/core/ipv4/ip.c
new file mode 100644
index 00000000..6f248716
--- /dev/null
+++ b/core/lwip/src/core/ipv4/ip.c
@@ -0,0 +1,857 @@
+/**
+ * @file
+ * This is the IPv4 layer implementation for incoming and outgoing IP traffic.
+ * 
+ * @see ip_frag.c
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+#include "lwip/ip.h"
+#include "lwip/def.h"
+#include "lwip/mem.h"
+#include "lwip/ip_frag.h"
+#include "lwip/inet_chksum.h"
+#include "lwip/netif.h"
+#include "lwip/icmp.h"
+#include "lwip/igmp.h"
+#include "lwip/raw.h"
+#include "lwip/udp.h"
+#include "lwip/tcp_impl.h"
+#include "lwip/snmp.h"
+#include "lwip/dhcp.h"
+#include "lwip/autoip.h"
+#include "lwip/stats.h"
+#include "arch/perf.h"
+
+#include <string.h>
+
+/** Set this to 0 in the rare case of wanting to call an extra function to
+ * generate the IP checksum (in contrast to calculating it on-the-fly). */
+#ifndef LWIP_INLINE_IP_CHKSUM
+#define LWIP_INLINE_IP_CHKSUM   1
+#endif
+#if LWIP_INLINE_IP_CHKSUM && CHECKSUM_GEN_IP
+#define CHECKSUM_GEN_IP_INLINE  1
+#else
+#define CHECKSUM_GEN_IP_INLINE  0
+#endif
+
+#if LWIP_DHCP || defined(LWIP_IP_ACCEPT_UDP_PORT)
+#define IP_ACCEPT_LINK_LAYER_ADDRESSING 1
+
+/** Some defines for DHCP to let link-layer-addressed packets through while the
+ * netif is down.
+ * To use this in your own application/protocol, define LWIP_IP_ACCEPT_UDP_PORT
+ * to return 1 if the port is accepted and 0 if the port is not accepted.
+ */
+#if LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT)
+/* accept DHCP client port and custom port */
+#define IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(port) (((port) == PP_NTOHS(DHCP_CLIENT_PORT)) \
+         || (LWIP_IP_ACCEPT_UDP_PORT(port)))
+#elif defined(LWIP_IP_ACCEPT_UDP_PORT) /* LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) */
+/* accept custom port only */
+#define IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(port) (LWIP_IP_ACCEPT_UDP_PORT(dst_port))
+#else /* LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) */
+/* accept DHCP client port only */
+#define IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(port) ((port) == PP_NTOHS(DHCP_CLIENT_PORT))
+#endif /* LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) */
+
+#else /* LWIP_DHCP */
+#define IP_ACCEPT_LINK_LAYER_ADDRESSING 0
+#endif /* LWIP_DHCP */
+
+/**
+ * The interface that provided the packet for the current callback
+ * invocation.
+ */
+struct netif *current_netif;
+
+/**
+ * Header of the input packet currently being processed.
+ */
+const struct ip_hdr *current_header;
+/** Source IP address of current_header */
+ip_addr_t current_iphdr_src;
+/** Destination IP address of current_header */
+ip_addr_t current_iphdr_dest;
+
+/** The IP header ID of the next outgoing IP packet */
+static u16_t ip_id;
+
+/**
+ * Finds the appropriate network interface for a given IP address. It
+ * searches the list of network interfaces linearly. A match is found
+ * if the masked IP address of the network interface equals the masked
+ * IP address given to the function.
+ *
+ * @param dest the destination IP address for which to find the route
+ * @return the netif on which to send to reach dest
+ */
+struct netif *
+ip_route(ip_addr_t *dest)
+{
+  struct netif *netif;
+
+  /* iterate through netifs */
+  for(netif = netif_list; netif != NULL; netif = netif->next) {
+    /* network mask matches? */
+    if (netif_is_up(netif)) {
+      if (ip_addr_netcmp(dest, &(netif->ip_addr), &(netif->netmask))) {
+        /* return netif on which to forward IP packet */
+        return netif;
+      }
+    }
+  }
+  if ((netif_default == NULL) || (!netif_is_up(netif_default))) {
+    LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip_route: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+      ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
+    IP_STATS_INC(ip.rterr);
+    snmp_inc_ipoutnoroutes();
+    return NULL;
+  }
+  /* no matching netif found, use default netif */
+  return netif_default;
+}
+
+#if IP_FORWARD
+/**
+ * Forwards an IP packet. It finds an appropriate route for the
+ * packet, decrements the TTL value of the packet, adjusts the
+ * checksum and outputs the packet on the appropriate interface.
+ *
+ * @param p the packet to forward (p->payload points to IP header)
+ * @param iphdr the IP header of the input packet
+ * @param inp the netif on which this packet was received
+ */
+static void
+ip_forward(struct pbuf *p, struct ip_hdr *iphdr, struct netif *inp)
+{
+  struct netif *netif;
+
+  PERF_START;
+
+  /* RFC3927 2.7: do not forward link-local addresses */
+  if (ip_addr_islinklocal(&current_iphdr_dest)) {
+    LWIP_DEBUGF(IP_DEBUG, ("ip_forward: not forwarding LLA %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+      ip4_addr1_16(&current_iphdr_dest), ip4_addr2_16(&current_iphdr_dest),
+      ip4_addr3_16(&current_iphdr_dest), ip4_addr4_16(&current_iphdr_dest)));
+    goto return_noroute;
+  }
+
+  /* Find network interface where to forward this IP packet to. */
+  netif = ip_route(&current_iphdr_dest);
+  if (netif == NULL) {
+    LWIP_DEBUGF(IP_DEBUG, ("ip_forward: no forwarding route for %"U16_F".%"U16_F".%"U16_F".%"U16_F" found\n",
+      ip4_addr1_16(&current_iphdr_dest), ip4_addr2_16(&current_iphdr_dest),
+      ip4_addr3_16(&current_iphdr_dest), ip4_addr4_16(&current_iphdr_dest)));
+    goto return_noroute;
+  }
+  /* Do not forward packets onto the same network interface on which
+   * they arrived. */
+  if (netif == inp) {
+    LWIP_DEBUGF(IP_DEBUG, ("ip_forward: not bouncing packets back on incoming interface.\n"));
+    goto return_noroute;
+  }
+
+  /* decrement TTL */
+  IPH_TTL_SET(iphdr, IPH_TTL(iphdr) - 1);
+  /* send ICMP if TTL == 0 */
+  if (IPH_TTL(iphdr) == 0) {
+    snmp_inc_ipinhdrerrors();
+#if LWIP_ICMP
+    /* Don't send ICMP messages in response to ICMP messages */
+    if (IPH_PROTO(iphdr) != IP_PROTO_ICMP) {
+      icmp_time_exceeded(p, ICMP_TE_TTL);
+    }
+#endif /* LWIP_ICMP */
+    return;
+  }
+
+  /* Incrementally update the IP checksum. */
+  if (IPH_CHKSUM(iphdr) >= PP_HTONS(0xffffU - 0x100)) {
+    IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + PP_HTONS(0x100) + 1);
+  } else {
+    IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + PP_HTONS(0x100));
+  }
+
+  LWIP_DEBUGF(IP_DEBUG, ("ip_forward: forwarding packet to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+    ip4_addr1_16(&current_iphdr_dest), ip4_addr2_16(&current_iphdr_dest),
+    ip4_addr3_16(&current_iphdr_dest), ip4_addr4_16(&current_iphdr_dest)));
+
+  IP_STATS_INC(ip.fw);
+  IP_STATS_INC(ip.xmit);
+  snmp_inc_ipforwdatagrams();
+
+  PERF_STOP("ip_forward");
+  /* transmit pbuf on chosen interface */
+  netif->output(netif, p, &current_iphdr_dest);
+  return;
+return_noroute:
+  snmp_inc_ipoutnoroutes();
+}
+#endif /* IP_FORWARD */
+
+/**
+ * This function is called by the network interface device driver when
+ * an IP packet is received. The function does the basic checks of the
+ * IP header such as packet size being at least larger than the header
+ * size etc. If the packet was not destined for us, the packet is
+ * forwarded (using ip_forward). The IP checksum is always checked.
+ *
+ * Finally, the packet is sent to the upper layer protocol input function.
+ * 
+ * @param p the received IP packet (p->payload points to IP header)
+ * @param inp the netif on which this packet was received
+ * @return ERR_OK if the packet was processed (could return ERR_* if it wasn't
+ *         processed, but currently always returns ERR_OK)
+ */
+err_t
+ip_input(struct pbuf *p, struct netif *inp)
+{
+  struct ip_hdr *iphdr;
+  struct netif *netif;
+  u16_t iphdr_hlen;
+  u16_t iphdr_len;
+#if IP_ACCEPT_LINK_LAYER_ADDRESSING
+  int check_ip_src=1;
+#endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */
+
+  IP_STATS_INC(ip.recv);
+  snmp_inc_ipinreceives();
+
+  /* identify the IP header */
+  iphdr = (struct ip_hdr *)p->payload;
+  if (IPH_V(iphdr) != 4) {
+    LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_WARNING, ("IP packet dropped due to bad version number %"U16_F"\n", IPH_V(iphdr)));
+    ip_debug_print(p);
+    pbuf_free(p);
+    IP_STATS_INC(ip.err);
+    IP_STATS_INC(ip.drop);
+    snmp_inc_ipinhdrerrors();
+    return ERR_OK;
+  }
+
+  /* obtain IP header length in number of 32-bit words */
+  iphdr_hlen = IPH_HL(iphdr);
+  /* calculate IP header length in bytes */
+  iphdr_hlen *= 4;
+  /* obtain ip length in bytes */
+  iphdr_len = ntohs(IPH_LEN(iphdr));
+
+  /* header length exceeds first pbuf length, or ip length exceeds total pbuf length? */
+  if ((iphdr_hlen > p->len) || (iphdr_len > p->tot_len)) {
+    if (iphdr_hlen > p->len) {
+      LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
+        ("IP header (len %"U16_F") does not fit in first pbuf (len %"U16_F"), IP packet dropped.\n",
+        iphdr_hlen, p->len));
+    }
+    if (iphdr_len > p->tot_len) {
+      LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
+        ("IP (len %"U16_F") is longer than pbuf (len %"U16_F"), IP packet dropped.\n",
+        iphdr_len, p->tot_len));
+    }
+    /* free (drop) packet pbufs */
+    pbuf_free(p);
+    IP_STATS_INC(ip.lenerr);
+    IP_STATS_INC(ip.drop);
+    snmp_inc_ipindiscards();
+    return ERR_OK;
+  }
+
+  /* verify checksum */
+#if CHECKSUM_CHECK_IP
+  if (inet_chksum(iphdr, iphdr_hlen) != 0) {
+
+    LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
+      ("Checksum (0x%"X16_F") failed, IP packet dropped.\n", inet_chksum(iphdr, iphdr_hlen)));
+    ip_debug_print(p);
+    pbuf_free(p);
+    IP_STATS_INC(ip.chkerr);
+    IP_STATS_INC(ip.drop);
+    snmp_inc_ipinhdrerrors();
+    return ERR_OK;
+  }
+#endif
+
+  /* Trim pbuf. This should have been done at the netif layer,
+   * but we'll do it anyway just to be sure that its done. */
+  pbuf_realloc(p, iphdr_len);
+
+  /* copy IP addresses to aligned ip_addr_t */
+  ip_addr_copy(current_iphdr_dest, iphdr->dest);
+  ip_addr_copy(current_iphdr_src, iphdr->src);
+
+  /* match packet against an interface, i.e. is this packet for us? */
+#if LWIP_IGMP
+  if (ip_addr_ismulticast(&current_iphdr_dest)) {
+    if ((inp->flags & NETIF_FLAG_IGMP) && (igmp_lookfor_group(inp, &current_iphdr_dest))) {
+      netif = inp;
+    } else {
+      netif = NULL;
+    }
+  } else
+#endif /* LWIP_IGMP */
+  {
+    /* start trying with inp. if that's not acceptable, start walking the
+       list of configured netifs.
+       'first' is used as a boolean to mark whether we started walking the list */
+    int first = 1;
+    netif = inp;
+    do {
+      LWIP_DEBUGF(IP_DEBUG, ("ip_input: iphdr->dest 0x%"X32_F" netif->ip_addr 0x%"X32_F" (0x%"X32_F", 0x%"X32_F", 0x%"X32_F")\n",
+          ip4_addr_get_u32(&iphdr->dest), ip4_addr_get_u32(&netif->ip_addr),
+          ip4_addr_get_u32(&iphdr->dest) & ip4_addr_get_u32(&netif->netmask),
+          ip4_addr_get_u32(&netif->ip_addr) & ip4_addr_get_u32(&netif->netmask),
+          ip4_addr_get_u32(&iphdr->dest) & ~ip4_addr_get_u32(&netif->netmask)));
+
+      /* interface is up and configured? */
+      if ((netif_is_up(netif)) && (!ip_addr_isany(&(netif->ip_addr)))) {
+        /* unicast to this interface address? */
+        if (ip_addr_cmp(&current_iphdr_dest, &(netif->ip_addr)) ||
+            /* or broadcast on this interface network address? */
+            ip_addr_isbroadcast(&current_iphdr_dest, netif)) {
+          LWIP_DEBUGF(IP_DEBUG, ("ip_input: packet accepted on interface %c%c\n",
+              netif->name[0], netif->name[1]));
+          /* break out of for loop */
+          break;
+        }
+#if LWIP_AUTOIP
+        /* connections to link-local addresses must persist after changing
+           the netif's address (RFC3927 ch. 1.9) */
+        if ((netif->autoip != NULL) &&
+            ip_addr_cmp(&current_iphdr_dest, &(netif->autoip->llipaddr))) {
+          LWIP_DEBUGF(IP_DEBUG, ("ip_input: LLA packet accepted on interface %c%c\n",
+              netif->name[0], netif->name[1]));
+          /* break out of for loop */
+          break;
+        }
+#endif /* LWIP_AUTOIP */
+      }
+      if (first) {
+        first = 0;
+        netif = netif_list;
+      } else {
+        netif = netif->next;
+      }
+      if (netif == inp) {
+        netif = netif->next;
+      }
+    } while(netif != NULL);
+  }
+
+#if IP_ACCEPT_LINK_LAYER_ADDRESSING
+  /* Pass DHCP messages regardless of destination address. DHCP traffic is addressed
+   * using link layer addressing (such as Ethernet MAC) so we must not filter on IP.
+   * According to RFC 1542 section 3.1.1, referred by RFC 2131).
+   *
+   * If you want to accept private broadcast communication while a netif is down,
+   * define LWIP_IP_ACCEPT_UDP_PORT(dst_port), e.g.:
+   *
+   * #define LWIP_IP_ACCEPT_UDP_PORT(dst_port) ((dst_port) == PP_NTOHS(12345))
+   */
+  if (netif == NULL) {
+    /* remote port is DHCP server? */
+    if (IPH_PROTO(iphdr) == IP_PROTO_UDP) {
+      struct udp_hdr *udphdr = (struct udp_hdr *)((u8_t *)iphdr + iphdr_hlen);
+      LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip_input: UDP packet to DHCP client port %"U16_F"\n",
+        ntohs(udphdr->dest)));
+      if (IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(udphdr->dest)) {
+        LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip_input: DHCP packet accepted.\n"));
+        netif = inp;
+        check_ip_src = 0;
+      }
+    }
+  }
+#endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */
+
+  /* broadcast or multicast packet source address? Compliant with RFC 1122: 3.2.1.3 */
+#if IP_ACCEPT_LINK_LAYER_ADDRESSING
+  /* DHCP servers need 0.0.0.0 to be allowed as source address (RFC 1.1.2.2: 3.2.1.3/a) */
+  if (check_ip_src && !ip_addr_isany(&current_iphdr_src))
+#endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */
+  {  if ((ip_addr_isbroadcast(&current_iphdr_src, inp)) ||
+         (ip_addr_ismulticast(&current_iphdr_src))) {
+      /* packet source is not valid */
+      LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("ip_input: packet source is not valid.\n"));
+      /* free (drop) packet pbufs */
+      pbuf_free(p);
+      IP_STATS_INC(ip.drop);
+      snmp_inc_ipinaddrerrors();
+      snmp_inc_ipindiscards();
+      return ERR_OK;
+    }
+  }
+
+  /* packet not for us? */
+  if (netif == NULL) {
+    /* packet not for us, route or discard */
+    LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip_input: packet not for us.\n"));
+#if IP_FORWARD
+    /* non-broadcast packet? */
+    if (!ip_addr_isbroadcast(&current_iphdr_dest, inp)) {
+      /* try to forward IP packet on (other) interfaces */
+      ip_forward(p, iphdr, inp);
+    } else
+#endif /* IP_FORWARD */
+    {
+      snmp_inc_ipinaddrerrors();
+      snmp_inc_ipindiscards();
+    }
+    pbuf_free(p);
+    return ERR_OK;
+  }
+  /* packet consists of multiple fragments? */
+  if ((IPH_OFFSET(iphdr) & PP_HTONS(IP_OFFMASK | IP_MF)) != 0) {
+#if IP_REASSEMBLY /* packet fragment reassembly code present? */
+    LWIP_DEBUGF(IP_DEBUG, ("IP packet is a fragment (id=0x%04"X16_F" tot_len=%"U16_F" len=%"U16_F" MF=%"U16_F" offset=%"U16_F"), calling ip_reass()\n",
+      ntohs(IPH_ID(iphdr)), p->tot_len, ntohs(IPH_LEN(iphdr)), !!(IPH_OFFSET(iphdr) & PP_HTONS(IP_MF)), (ntohs(IPH_OFFSET(iphdr)) & IP_OFFMASK)*8));
+    /* reassemble the packet*/
+    p = ip_reass(p);
+    /* packet not fully reassembled yet? */
+    if (p == NULL) {
+      return ERR_OK;
+    }
+    iphdr = (struct ip_hdr *)p->payload;
+#else /* IP_REASSEMBLY == 0, no packet fragment reassembly code present */
+    pbuf_free(p);
+    LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("IP packet dropped since it was fragmented (0x%"X16_F") (while IP_REASSEMBLY == 0).\n",
+      ntohs(IPH_OFFSET(iphdr))));
+    IP_STATS_INC(ip.opterr);
+    IP_STATS_INC(ip.drop);
+    /* unsupported protocol feature */
+    snmp_inc_ipinunknownprotos();
+    return ERR_OK;
+#endif /* IP_REASSEMBLY */
+  }
+
+#if IP_OPTIONS_ALLOWED == 0 /* no support for IP options in the IP header? */
+
+#if LWIP_IGMP
+  /* there is an extra "router alert" option in IGMP messages which we allow for but do not police */
+  if((iphdr_hlen > IP_HLEN) &&  (IPH_PROTO(iphdr) != IP_PROTO_IGMP)) {
+#else
+  if (iphdr_hlen > IP_HLEN) {
+#endif /* LWIP_IGMP */
+    LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("IP packet dropped since there were IP options (while IP_OPTIONS_ALLOWED == 0).\n"));
+    pbuf_free(p);
+    IP_STATS_INC(ip.opterr);
+    IP_STATS_INC(ip.drop);
+    /* unsupported protocol feature */
+    snmp_inc_ipinunknownprotos();
+    return ERR_OK;
+  }
+#endif /* IP_OPTIONS_ALLOWED == 0 */
+
+  /* send to upper layers */
+  LWIP_DEBUGF(IP_DEBUG, ("ip_input: \n"));
+  ip_debug_print(p);
+  LWIP_DEBUGF(IP_DEBUG, ("ip_input: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len));
+
+  current_netif = inp;
+  current_header = iphdr;
+
+#if LWIP_RAW
+  /* raw input did not eat the packet? */
+  if (raw_input(p, inp) == 0)
+#endif /* LWIP_RAW */
+  {
+
+    switch (IPH_PROTO(iphdr)) {
+#if LWIP_UDP
+    case IP_PROTO_UDP:
+#if LWIP_UDPLITE
+    case IP_PROTO_UDPLITE:
+#endif /* LWIP_UDPLITE */
+      snmp_inc_ipindelivers();
+      udp_input(p, inp);
+      break;
+#endif /* LWIP_UDP */
+#if LWIP_TCP
+    case IP_PROTO_TCP:
+      snmp_inc_ipindelivers();
+      tcp_input(p, inp);
+      break;
+#endif /* LWIP_TCP */
+#if LWIP_ICMP
+    case IP_PROTO_ICMP:
+      snmp_inc_ipindelivers();
+      icmp_input(p, inp);
+      break;
+#endif /* LWIP_ICMP */
+#if LWIP_IGMP
+    case IP_PROTO_IGMP:
+      igmp_input(p, inp, &current_iphdr_dest);
+      break;
+#endif /* LWIP_IGMP */
+    default:
+#if LWIP_ICMP
+      /* send ICMP destination protocol unreachable unless is was a broadcast */
+      if (!ip_addr_isbroadcast(&current_iphdr_dest, inp) &&
+          !ip_addr_ismulticast(&current_iphdr_dest)) {
+        p->payload = iphdr;
+        icmp_dest_unreach(p, ICMP_DUR_PROTO);
+      }
+#endif /* LWIP_ICMP */
+      pbuf_free(p);
+
+      LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("Unsupported transport protocol %"U16_F"\n", IPH_PROTO(iphdr)));
+
+      IP_STATS_INC(ip.proterr);
+      IP_STATS_INC(ip.drop);
+      snmp_inc_ipinunknownprotos();
+    }
+  }
+
+  current_netif = NULL;
+  current_header = NULL;
+  ip_addr_set_any(&current_iphdr_src);
+  ip_addr_set_any(&current_iphdr_dest);
+
+  return ERR_OK;
+}
+
+/**
+ * Sends an IP packet on a network interface. This function constructs
+ * the IP header and calculates the IP header checksum. If the source
+ * IP address is NULL, the IP address of the outgoing network
+ * interface is filled in as source address.
+ * If the destination IP address is IP_HDRINCL, p is assumed to already
+ * include an IP header and p->payload points to it instead of the data.
+ *
+ * @param p the packet to send (p->payload points to the data, e.g. next
+            protocol header; if dest == IP_HDRINCL, p already includes an IP
+            header and p->payload points to that IP header)
+ * @param src the source IP address to send from (if src == IP_ADDR_ANY, the
+ *         IP  address of the netif used to send is used as source address)
+ * @param dest the destination IP address to send the packet to
+ * @param ttl the TTL value to be set in the IP header
+ * @param tos the TOS value to be set in the IP header
+ * @param proto the PROTOCOL to be set in the IP header
+ * @param netif the netif on which to send this packet
+ * @return ERR_OK if the packet was sent OK
+ *         ERR_BUF if p doesn't have enough space for IP/LINK headers
+ *         returns errors returned by netif->output
+ *
+ * @note ip_id: RFC791 "some host may be able to simply use
+ *  unique identifiers independent of destination"
+ */
+err_t
+ip_output_if(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest,
+             u8_t ttl, u8_t tos,
+             u8_t proto, struct netif *netif)
+{
+#if IP_OPTIONS_SEND
+  return ip_output_if_opt(p, src, dest, ttl, tos, proto, netif, NULL, 0);
+}
+
+/**
+ * Same as ip_output_if() but with the possibility to include IP options:
+ *
+ * @ param ip_options pointer to the IP options, copied into the IP header
+ * @ param optlen length of ip_options
+ */
+err_t ip_output_if_opt(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest,
+       u8_t ttl, u8_t tos, u8_t proto, struct netif *netif, void *ip_options,
+       u16_t optlen)
+{
+#endif /* IP_OPTIONS_SEND */
+  struct ip_hdr *iphdr;
+  ip_addr_t dest_addr;
+#if CHECKSUM_GEN_IP_INLINE
+  u32_t chk_sum = 0;
+#endif /* CHECKSUM_GEN_IP_INLINE */
+
+  /* pbufs passed to IP must have a ref-count of 1 as their payload pointer
+     gets altered as the packet is passed down the stack */
+  LWIP_ASSERT("p->ref == 1", p->ref == 1);
+
+  snmp_inc_ipoutrequests();
+
+  /* Should the IP header be generated or is it already included in p? */
+  if (dest != IP_HDRINCL) {
+    u16_t ip_hlen = IP_HLEN;
+#if IP_OPTIONS_SEND
+    u16_t optlen_aligned = 0;
+    if (optlen != 0) {
+#if CHECKSUM_GEN_IP_INLINE
+      int i;
+#endif /* CHECKSUM_GEN_IP_INLINE */
+      /* round up to a multiple of 4 */
+      optlen_aligned = ((optlen + 3) & ~3);
+      ip_hlen += optlen_aligned;
+      /* First write in the IP options */
+      if (pbuf_header(p, optlen_aligned)) {
+        LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip_output_if_opt: not enough room for IP options in pbuf\n"));
+        IP_STATS_INC(ip.err);
+        snmp_inc_ipoutdiscards();
+        return ERR_BUF;
+      }
+      MEMCPY(p->payload, ip_options, optlen);
+      if (optlen < optlen_aligned) {
+        /* zero the remaining bytes */
+        memset(((char*)p->payload) + optlen, 0, optlen_aligned - optlen);
+      }
+#if CHECKSUM_GEN_IP_INLINE
+      for (i = 0; i < optlen_aligned/2; i++) {
+        chk_sum += ((u16_t*)p->payload)[i];
+      }
+#endif /* CHECKSUM_GEN_IP_INLINE */
+    }
+#endif /* IP_OPTIONS_SEND */
+    /* generate IP header */
+    if (pbuf_header(p, IP_HLEN)) {
+      LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip_output: not enough room for IP header in pbuf\n"));
+
+      IP_STATS_INC(ip.err);
+      snmp_inc_ipoutdiscards();
+      return ERR_BUF;
+    }
+
+    iphdr = (struct ip_hdr *)p->payload;
+    LWIP_ASSERT("check that first pbuf can hold struct ip_hdr",
+               (p->len >= sizeof(struct ip_hdr)));
+
+    IPH_TTL_SET(iphdr, ttl);
+    IPH_PROTO_SET(iphdr, proto);
+#if CHECKSUM_GEN_IP_INLINE
+    chk_sum += LWIP_MAKE_U16(proto, ttl);
+#endif /* CHECKSUM_GEN_IP_INLINE */
+
+    /* dest cannot be NULL here */
+    ip_addr_copy(iphdr->dest, *dest);
+#if CHECKSUM_GEN_IP_INLINE
+    chk_sum += ip4_addr_get_u32(&iphdr->dest) & 0xFFFF;
+    chk_sum += ip4_addr_get_u32(&iphdr->dest) >> 16;
+#endif /* CHECKSUM_GEN_IP_INLINE */
+
+    IPH_VHLTOS_SET(iphdr, 4, ip_hlen / 4, tos);
+#if CHECKSUM_GEN_IP_INLINE
+    chk_sum += iphdr->_v_hl_tos;
+#endif /* CHECKSUM_GEN_IP_INLINE */
+    IPH_LEN_SET(iphdr, htons(p->tot_len));
+#if CHECKSUM_GEN_IP_INLINE
+    chk_sum += iphdr->_len;
+#endif /* CHECKSUM_GEN_IP_INLINE */
+    IPH_OFFSET_SET(iphdr, 0);
+    IPH_ID_SET(iphdr, htons(ip_id));
+#if CHECKSUM_GEN_IP_INLINE
+    chk_sum += iphdr->_id;
+#endif /* CHECKSUM_GEN_IP_INLINE */
+    ++ip_id;
+
+    if (ip_addr_isany(src)) {
+      ip_addr_copy(iphdr->src, netif->ip_addr);
+    } else {
+      /* src cannot be NULL here */
+      ip_addr_copy(iphdr->src, *src);
+    }
+
+#if CHECKSUM_GEN_IP_INLINE
+    chk_sum += ip4_addr_get_u32(&iphdr->src) & 0xFFFF;
+    chk_sum += ip4_addr_get_u32(&iphdr->src) >> 16;
+    chk_sum = (chk_sum >> 16) + (chk_sum & 0xFFFF);
+    chk_sum = (chk_sum >> 16) + chk_sum;
+    chk_sum = ~chk_sum;
+    iphdr->_chksum = chk_sum; /* network order */
+#else /* CHECKSUM_GEN_IP_INLINE */
+    IPH_CHKSUM_SET(iphdr, 0);
+#if CHECKSUM_GEN_IP
+    IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, ip_hlen));
+#endif
+#endif /* CHECKSUM_GEN_IP_INLINE */
+  } else {
+    /* IP header already included in p */
+    iphdr = (struct ip_hdr *)p->payload;
+    ip_addr_copy(dest_addr, iphdr->dest);
+    dest = &dest_addr;
+  }
+
+  IP_STATS_INC(ip.xmit);
+
+  LWIP_DEBUGF(IP_DEBUG, ("ip_output_if: %c%c%"U16_F"\n", netif->name[0], netif->name[1], netif->num));
+  ip_debug_print(p);
+
+#if ENABLE_LOOPBACK
+  if (ip_addr_cmp(dest, &netif->ip_addr)) {
+    /* Packet to self, enqueue it for loopback */
+    LWIP_DEBUGF(IP_DEBUG, ("netif_loop_output()"));
+    return netif_loop_output(netif, p, dest);
+  }
+#if LWIP_IGMP
+  if ((p->flags & PBUF_FLAG_MCASTLOOP) != 0) {
+    netif_loop_output(netif, p, dest);
+  }
+#endif /* LWIP_IGMP */
+#endif /* ENABLE_LOOPBACK */
+#if IP_FRAG
+  /* don't fragment if interface has mtu set to 0 [loopif] */
+  if (netif->mtu && (p->tot_len > netif->mtu)) {
+    return ip_frag(p, netif, dest);
+  }
+#endif /* IP_FRAG */
+
+  LWIP_DEBUGF(IP_DEBUG, ("netif->output()"));
+  return netif->output(netif, p, dest);
+}
+
+/**
+ * Simple interface to ip_output_if. It finds the outgoing network
+ * interface and calls upon ip_output_if to do the actual work.
+ *
+ * @param p the packet to send (p->payload points to the data, e.g. next
+            protocol header; if dest == IP_HDRINCL, p already includes an IP
+            header and p->payload points to that IP header)
+ * @param src the source IP address to send from (if src == IP_ADDR_ANY, the
+ *         IP  address of the netif used to send is used as source address)
+ * @param dest the destination IP address to send the packet to
+ * @param ttl the TTL value to be set in the IP header
+ * @param tos the TOS value to be set in the IP header
+ * @param proto the PROTOCOL to be set in the IP header
+ *
+ * @return ERR_RTE if no route is found
+ *         see ip_output_if() for more return values
+ */
+err_t
+ip_output(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest,
+          u8_t ttl, u8_t tos, u8_t proto)
+{
+  struct netif *netif;
+
+  /* pbufs passed to IP must have a ref-count of 1 as their payload pointer
+     gets altered as the packet is passed down the stack */
+  LWIP_ASSERT("p->ref == 1", p->ref == 1);
+
+  if ((netif = ip_route(dest)) == NULL) {
+    LWIP_DEBUGF(IP_DEBUG, ("ip_output: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+      ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
+    IP_STATS_INC(ip.rterr);
+    return ERR_RTE;
+  }
+
+  return ip_output_if(p, src, dest, ttl, tos, proto, netif);
+}
+
+#if LWIP_NETIF_HWADDRHINT
+/** Like ip_output, but takes and addr_hint pointer that is passed on to netif->addr_hint
+ *  before calling ip_output_if.
+ *
+ * @param p the packet to send (p->payload points to the data, e.g. next
+            protocol header; if dest == IP_HDRINCL, p already includes an IP
+            header and p->payload points to that IP header)
+ * @param src the source IP address to send from (if src == IP_ADDR_ANY, the
+ *         IP  address of the netif used to send is used as source address)
+ * @param dest the destination IP address to send the packet to
+ * @param ttl the TTL value to be set in the IP header
+ * @param tos the TOS value to be set in the IP header
+ * @param proto the PROTOCOL to be set in the IP header
+ * @param addr_hint address hint pointer set to netif->addr_hint before
+ *        calling ip_output_if()
+ *
+ * @return ERR_RTE if no route is found
+ *         see ip_output_if() for more return values
+ */
+err_t
+ip_output_hinted(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest,
+          u8_t ttl, u8_t tos, u8_t proto, u8_t *addr_hint)
+{
+  struct netif *netif;
+  err_t err;
+
+  /* pbufs passed to IP must have a ref-count of 1 as their payload pointer
+     gets altered as the packet is passed down the stack */
+  LWIP_ASSERT("p->ref == 1", p->ref == 1);
+
+  if ((netif = ip_route(dest)) == NULL) {
+    LWIP_DEBUGF(IP_DEBUG, ("ip_output: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+      ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
+    IP_STATS_INC(ip.rterr);
+    return ERR_RTE;
+  }
+
+  netif->addr_hint = addr_hint;
+  err = ip_output_if(p, src, dest, ttl, tos, proto, netif);
+  netif->addr_hint = NULL;
+
+  return err;
+}
+#endif /* LWIP_NETIF_HWADDRHINT*/
+
+#if IP_DEBUG
+/* Print an IP header by using LWIP_DEBUGF
+ * @param p an IP packet, p->payload pointing to the IP header
+ */
+void
+ip_debug_print(struct pbuf *p)
+{
+  struct ip_hdr *iphdr = (struct ip_hdr *)p->payload;
+  u8_t *payload;
+
+  payload = (u8_t *)iphdr + IP_HLEN;
+
+  LWIP_DEBUGF(IP_DEBUG, ("IP header:\n"));
+  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
+  LWIP_DEBUGF(IP_DEBUG, ("|%2"S16_F" |%2"S16_F" |  0x%02"X16_F" |     %5"U16_F"     | (v, hl, tos, len)\n",
+                    IPH_V(iphdr),
+                    IPH_HL(iphdr),
+                    IPH_TOS(iphdr),
+                    ntohs(IPH_LEN(iphdr))));
+  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
+  LWIP_DEBUGF(IP_DEBUG, ("|    %5"U16_F"      |%"U16_F"%"U16_F"%"U16_F"|    %4"U16_F"   | (id, flags, offset)\n",
+                    ntohs(IPH_ID(iphdr)),
+                    ntohs(IPH_OFFSET(iphdr)) >> 15 & 1,
+                    ntohs(IPH_OFFSET(iphdr)) >> 14 & 1,
+                    ntohs(IPH_OFFSET(iphdr)) >> 13 & 1,
+                    ntohs(IPH_OFFSET(iphdr)) & IP_OFFMASK));
+  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
+  LWIP_DEBUGF(IP_DEBUG, ("|  %3"U16_F"  |  %3"U16_F"  |    0x%04"X16_F"     | (ttl, proto, chksum)\n",
+                    IPH_TTL(iphdr),
+                    IPH_PROTO(iphdr),
+                    ntohs(IPH_CHKSUM(iphdr))));
+  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
+  LWIP_DEBUGF(IP_DEBUG, ("|  %3"U16_F"  |  %3"U16_F"  |  %3"U16_F"  |  %3"U16_F"  | (src)\n",
+                    ip4_addr1_16(&iphdr->src),
+                    ip4_addr2_16(&iphdr->src),
+                    ip4_addr3_16(&iphdr->src),
+                    ip4_addr4_16(&iphdr->src)));
+  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
+  LWIP_DEBUGF(IP_DEBUG, ("|  %3"U16_F"  |  %3"U16_F"  |  %3"U16_F"  |  %3"U16_F"  | (dest)\n",
+                    ip4_addr1_16(&iphdr->dest),
+                    ip4_addr2_16(&iphdr->dest),
+                    ip4_addr3_16(&iphdr->dest),
+                    ip4_addr4_16(&iphdr->dest)));
+  LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
+}
+#endif /* IP_DEBUG */
diff --git a/core/lwip/src/core/ipv4/ip_addr.c b/core/lwip/src/core/ipv4/ip_addr.c
new file mode 100644
index 00000000..8f633ff2
--- /dev/null
+++ b/core/lwip/src/core/ipv4/ip_addr.c
@@ -0,0 +1,312 @@
+/**
+ * @file
+ * This is the IPv4 address tools implementation.
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+#include "lwip/ip_addr.h"
+#include "lwip/netif.h"
+
+/* used by IP_ADDR_ANY and IP_ADDR_BROADCAST in ip_addr.h */
+const ip_addr_t ip_addr_any = { IPADDR_ANY };
+const ip_addr_t ip_addr_broadcast = { IPADDR_BROADCAST };
+
+/**
+ * Determine if an address is a broadcast address on a network interface 
+ * 
+ * @param addr address to be checked
+ * @param netif the network interface against which the address is checked
+ * @return returns non-zero if the address is a broadcast address
+ */
+u8_t
+ip4_addr_isbroadcast(u32_t addr, const struct netif *netif)
+{
+  ip_addr_t ipaddr;
+  ip4_addr_set_u32(&ipaddr, addr);
+
+  /* all ones (broadcast) or all zeroes (old skool broadcast) */
+  if ((~addr == IPADDR_ANY) ||
+      (addr == IPADDR_ANY)) {
+    return 1;
+  /* no broadcast support on this network interface? */
+  } else if ((netif->flags & NETIF_FLAG_BROADCAST) == 0) {
+    /* the given address cannot be a broadcast address
+     * nor can we check against any broadcast addresses */
+    return 0;
+  /* address matches network interface address exactly? => no broadcast */
+  } else if (addr == ip4_addr_get_u32(&netif->ip_addr)) {
+    return 0;
+  /*  on the same (sub) network... */
+  } else if (ip_addr_netcmp(&ipaddr, &(netif->ip_addr), &(netif->netmask))
+         /* ...and host identifier bits are all ones? =>... */
+          && ((addr & ~ip4_addr_get_u32(&netif->netmask)) ==
+           (IPADDR_BROADCAST & ~ip4_addr_get_u32(&netif->netmask)))) {
+    /* => network broadcast address */
+    return 1;
+  } else {
+    return 0;
+  }
+}
+
+/** Checks if a netmask is valid (starting with ones, then only zeros)
+ *
+ * @param netmask the IPv4 netmask to check (in network byte order!)
+ * @return 1 if the netmask is valid, 0 if it is not
+ */
+u8_t
+ip4_addr_netmask_valid(u32_t netmask)
+{
+  u32_t mask;
+  u32_t nm_hostorder = lwip_htonl(netmask);
+
+  /* first, check for the first zero */
+  for (mask = 1UL << 31 ; mask != 0; mask >>= 1) {
+    if ((nm_hostorder & mask) == 0) {
+      break;
+    }
+  }
+  /* then check that there is no one */
+  for (; mask != 0; mask >>= 1) {
+    if ((nm_hostorder & mask) != 0) {
+      /* there is a one after the first zero -> invalid */
+      return 0;
+    }
+  }
+  /* no one after the first zero -> valid */
+  return 1;
+}
+
+/* Here for now until needed in other places in lwIP */
+#ifndef isprint
+#define in_range(c, lo, up)  ((u8_t)c >= lo && (u8_t)c <= up)
+#define isprint(c)           in_range(c, 0x20, 0x7f)
+#define isdigit(c)           in_range(c, '0', '9')
+#define isxdigit(c)          (isdigit(c) || in_range(c, 'a', 'f') || in_range(c, 'A', 'F'))
+#define islower(c)           in_range(c, 'a', 'z')
+#define isspace(c)           (c == ' ' || c == '\f' || c == '\n' || c == '\r' || c == '\t' || c == '\v')
+#endif
+
+/**
+ * Ascii internet address interpretation routine.
+ * The value returned is in network order.
+ *
+ * @param cp IP address in ascii represenation (e.g. "127.0.0.1")
+ * @return ip address in network order
+ */
+u32_t
+ipaddr_addr(const char *cp)
+{
+  ip_addr_t val;
+
+  if (ipaddr_aton(cp, &val)) {
+    return ip4_addr_get_u32(&val);
+  }
+  return (IPADDR_NONE);
+}
+
+/**
+ * Check whether "cp" is a valid ascii representation
+ * of an Internet address and convert to a binary address.
+ * Returns 1 if the address is valid, 0 if not.
+ * This replaces inet_addr, the return value from which
+ * cannot distinguish between failure and a local broadcast address.
+ *
+ * @param cp IP address in ascii represenation (e.g. "127.0.0.1")
+ * @param addr pointer to which to save the ip address in network order
+ * @return 1 if cp could be converted to addr, 0 on failure
+ */
+int
+ipaddr_aton(const char *cp, ip_addr_t *addr)
+{
+  u32_t val;
+  u8_t base;
+  char c;
+  u32_t parts[4];
+  u32_t *pp = parts;
+
+  c = *cp;
+  for (;;) {
+    /*
+     * Collect number up to ``.''.
+     * Values are specified as for C:
+     * 0x=hex, 0=octal, 1-9=decimal.
+     */
+    if (!isdigit(c))
+      return (0);
+    val = 0;
+    base = 10;
+    if (c == '0') {
+      c = *++cp;
+      if (c == 'x' || c == 'X') {
+        base = 16;
+        c = *++cp;
+      } else
+        base = 8;
+    }
+    for (;;) {
+      if (isdigit(c)) {
+        val = (val * base) + (int)(c - '0');
+        c = *++cp;
+      } else if (base == 16 && isxdigit(c)) {
+        val = (val << 4) | (int)(c + 10 - (islower(c) ? 'a' : 'A'));
+        c = *++cp;
+      } else
+        break;
+    }
+    if (c == '.') {
+      /*
+       * Internet format:
+       *  a.b.c.d
+       *  a.b.c   (with c treated as 16 bits)
+       *  a.b (with b treated as 24 bits)
+       */
+      if (pp >= parts + 3) {
+        return (0);
+      }
+      *pp++ = val;
+      c = *++cp;
+    } else
+      break;
+  }
+  /*
+   * Check for trailing characters.
+   */
+  if (c != '\0' && !isspace(c)) {
+    return (0);
+  }
+  /*
+   * Concoct the address according to
+   * the number of parts specified.
+   */
+  switch (pp - parts + 1) {
+
+  case 0:
+    return (0);       /* initial nondigit */
+
+  case 1:             /* a -- 32 bits */
+    break;
+
+  case 2:             /* a.b -- 8.24 bits */
+    if (val > 0xffffffUL) {
+      return (0);
+    }
+    val |= parts[0] << 24;
+    break;
+
+  case 3:             /* a.b.c -- 8.8.16 bits */
+    if (val > 0xffff) {
+      return (0);
+    }
+    val |= (parts[0] << 24) | (parts[1] << 16);
+    break;
+
+  case 4:             /* a.b.c.d -- 8.8.8.8 bits */
+    if (val > 0xff) {
+      return (0);
+    }
+    val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
+    break;
+  default:
+    LWIP_ASSERT("unhandled", 0);
+    break;
+  }
+  if (addr) {
+    ip4_addr_set_u32(addr, htonl(val));
+  }
+  return (1);
+}
+
+/**
+ * Convert numeric IP address into decimal dotted ASCII representation.
+ * returns ptr to static buffer; not reentrant!
+ *
+ * @param addr ip address in network order to convert
+ * @return pointer to a global static (!) buffer that holds the ASCII
+ *         represenation of addr
+ */
+char *
+ipaddr_ntoa(const ip_addr_t *addr)
+{
+  static char str[16];
+  return ipaddr_ntoa_r(addr, str, 16);
+}
+
+/**
+ * Same as ipaddr_ntoa, but reentrant since a user-supplied buffer is used.
+ *
+ * @param addr ip address in network order to convert
+ * @param buf target buffer where the string is stored
+ * @param buflen length of buf
+ * @return either pointer to buf which now holds the ASCII
+ *         representation of addr or NULL if buf was too small
+ */
+char *ipaddr_ntoa_r(const ip_addr_t *addr, char *buf, int buflen)
+{
+  u32_t s_addr;
+  char inv[3];
+  char *rp;
+  u8_t *ap;
+  u8_t rem;
+  u8_t n;
+  u8_t i;
+  int len = 0;
+
+  s_addr = ip4_addr_get_u32(addr);
+
+  rp = buf;
+  ap = (u8_t *)&s_addr;
+  for(n = 0; n < 4; n++) {
+    i = 0;
+    do {
+      rem = *ap % (u8_t)10;
+      *ap /= (u8_t)10;
+      inv[i++] = '0' + rem;
+    } while(*ap);
+    while(i--) {
+      if (len++ >= buflen) {
+        return NULL;
+      }
+      *rp++ = inv[i];
+    }
+    if (len++ >= buflen) {
+      return NULL;
+    }
+    *rp++ = '.';
+    ap++;
+  }
+  *--rp = 0;
+  return buf;
+}
diff --git a/core/lwip/src/core/ipv4/ip_frag.c b/core/lwip/src/core/ipv4/ip_frag.c
new file mode 100644
index 00000000..8d184345
--- /dev/null
+++ b/core/lwip/src/core/ipv4/ip_frag.c
@@ -0,0 +1,863 @@
+/**
+ * @file
+ * This is the IPv4 packet segmentation and reassembly implementation.
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Jani Monoses <jani@iv.ro> 
+ *         Simon Goldschmidt
+ * original reassembly code by Adam Dunkels <adam@sics.se>
+ * 
+ */
+
+#include "lwip/opt.h"
+#include "lwip/ip_frag.h"
+#include "lwip/def.h"
+#include "lwip/inet_chksum.h"
+#include "lwip/netif.h"
+#include "lwip/snmp.h"
+#include "lwip/stats.h"
+#include "lwip/icmp.h"
+
+#include <string.h>
+
+#if IP_REASSEMBLY
+/**
+ * The IP reassembly code currently has the following limitations:
+ * - IP header options are not supported
+ * - fragments must not overlap (e.g. due to different routes),
+ *   currently, overlapping or duplicate fragments are thrown away
+ *   if IP_REASS_CHECK_OVERLAP=1 (the default)!
+ *
+ * @todo: work with IP header options
+ */
+
+/** Setting this to 0, you can turn off checking the fragments for overlapping
+ * regions. The code gets a little smaller. Only use this if you know that
+ * overlapping won't occur on your network! */
+#ifndef IP_REASS_CHECK_OVERLAP
+#define IP_REASS_CHECK_OVERLAP 1
+#endif /* IP_REASS_CHECK_OVERLAP */
+
+/** Set to 0 to prevent freeing the oldest datagram when the reassembly buffer is
+ * full (IP_REASS_MAX_PBUFS pbufs are enqueued). The code gets a little smaller.
+ * Datagrams will be freed by timeout only. Especially useful when MEMP_NUM_REASSDATA
+ * is set to 1, so one datagram can be reassembled at a time, only. */
+#ifndef IP_REASS_FREE_OLDEST
+#define IP_REASS_FREE_OLDEST 1
+#endif /* IP_REASS_FREE_OLDEST */
+
+#define IP_REASS_FLAG_LASTFRAG 0x01
+
+/** This is a helper struct which holds the starting
+ * offset and the ending offset of this fragment to
+ * easily chain the fragments.
+ * It has the same packing requirements as the IP header, since it replaces
+ * the IP header in memory in incoming fragments (after copying it) to keep
+ * track of the various fragments. (-> If the IP header doesn't need packing,
+ * this struct doesn't need packing, too.)
+ */
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct ip_reass_helper {
+  PACK_STRUCT_FIELD(struct pbuf *next_pbuf);
+  PACK_STRUCT_FIELD(u16_t start);
+  PACK_STRUCT_FIELD(u16_t end);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+#define IP_ADDRESSES_AND_ID_MATCH(iphdrA, iphdrB)  \
+  (ip_addr_cmp(&(iphdrA)->src, &(iphdrB)->src) && \
+   ip_addr_cmp(&(iphdrA)->dest, &(iphdrB)->dest) && \
+   IPH_ID(iphdrA) == IPH_ID(iphdrB)) ? 1 : 0
+
+/* global variables */
+static struct ip_reassdata *reassdatagrams;
+static u16_t ip_reass_pbufcount;
+
+/* function prototypes */
+static void ip_reass_dequeue_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev);
+static int ip_reass_free_complete_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev);
+
+/**
+ * Reassembly timer base function
+ * for both NO_SYS == 0 and 1 (!).
+ *
+ * Should be called every 1000 msec (defined by IP_TMR_INTERVAL).
+ */
+void
+ip_reass_tmr(void)
+{
+  struct ip_reassdata *r, *prev = NULL;
+
+  r = reassdatagrams;
+  while (r != NULL) {
+    /* Decrement the timer. Once it reaches 0,
+     * clean up the incomplete fragment assembly */
+    if (r->timer > 0) {
+      r->timer--;
+      LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer dec %"U16_F"\n",(u16_t)r->timer));
+      prev = r;
+      r = r->next;
+    } else {
+      /* reassembly timed out */
+      struct ip_reassdata *tmp;
+      LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer timed out\n"));
+      tmp = r;
+      /* get the next pointer before freeing */
+      r = r->next;
+      /* free the helper struct and all enqueued pbufs */
+      ip_reass_free_complete_datagram(tmp, prev);
+     }
+   }
+}
+
+/**
+ * Free a datagram (struct ip_reassdata) and all its pbufs.
+ * Updates the total count of enqueued pbufs (ip_reass_pbufcount),
+ * SNMP counters and sends an ICMP time exceeded packet.
+ *
+ * @param ipr datagram to free
+ * @param prev the previous datagram in the linked list
+ * @return the number of pbufs freed
+ */
+static int
+ip_reass_free_complete_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev)
+{
+  u16_t pbufs_freed = 0;
+  u8_t clen;
+  struct pbuf *p;
+  struct ip_reass_helper *iprh;
+
+  LWIP_ASSERT("prev != ipr", prev != ipr);
+  if (prev != NULL) {
+    LWIP_ASSERT("prev->next == ipr", prev->next == ipr);
+  }
+
+  snmp_inc_ipreasmfails();
+#if LWIP_ICMP
+  iprh = (struct ip_reass_helper *)ipr->p->payload;
+  if (iprh->start == 0) {
+    /* The first fragment was received, send ICMP time exceeded. */
+    /* First, de-queue the first pbuf from r->p. */
+    p = ipr->p;
+    ipr->p = iprh->next_pbuf;
+    /* Then, copy the original header into it. */
+    SMEMCPY(p->payload, &ipr->iphdr, IP_HLEN);
+    icmp_time_exceeded(p, ICMP_TE_FRAG);
+    clen = pbuf_clen(p);
+    LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
+    pbufs_freed += clen;
+    pbuf_free(p);
+  }
+#endif /* LWIP_ICMP */
+
+  /* First, free all received pbufs.  The individual pbufs need to be released 
+     separately as they have not yet been chained */
+  p = ipr->p;
+  while (p != NULL) {
+    struct pbuf *pcur;
+    iprh = (struct ip_reass_helper *)p->payload;
+    pcur = p;
+    /* get the next pointer before freeing */
+    p = iprh->next_pbuf;
+    clen = pbuf_clen(pcur);
+    LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
+    pbufs_freed += clen;
+    pbuf_free(pcur);
+  }
+  /* Then, unchain the struct ip_reassdata from the list and free it. */
+  ip_reass_dequeue_datagram(ipr, prev);
+  LWIP_ASSERT("ip_reass_pbufcount >= clen", ip_reass_pbufcount >= pbufs_freed);
+  ip_reass_pbufcount -= pbufs_freed;
+
+  return pbufs_freed;
+}
+
+#if IP_REASS_FREE_OLDEST
+/**
+ * Free the oldest datagram to make room for enqueueing new fragments.
+ * The datagram 'fraghdr' belongs to is not freed!
+ *
+ * @param fraghdr IP header of the current fragment
+ * @param pbufs_needed number of pbufs needed to enqueue
+ *        (used for freeing other datagrams if not enough space)
+ * @return the number of pbufs freed
+ */
+static int
+ip_reass_remove_oldest_datagram(struct ip_hdr *fraghdr, int pbufs_needed)
+{
+  /* @todo Can't we simply remove the last datagram in the
+   *       linked list behind reassdatagrams?
+   */
+  struct ip_reassdata *r, *oldest, *prev;
+  int pbufs_freed = 0, pbufs_freed_current;
+  int other_datagrams;
+
+  /* Free datagrams until being allowed to enqueue 'pbufs_needed' pbufs,
+   * but don't free the datagram that 'fraghdr' belongs to! */
+  do {
+    oldest = NULL;
+    prev = NULL;
+    other_datagrams = 0;
+    r = reassdatagrams;
+    while (r != NULL) {
+      if (!IP_ADDRESSES_AND_ID_MATCH(&r->iphdr, fraghdr)) {
+        /* Not the same datagram as fraghdr */
+        other_datagrams++;
+        if (oldest == NULL) {
+          oldest = r;
+        } else if (r->timer <= oldest->timer) {
+          /* older than the previous oldest */
+          oldest = r;
+        }
+      }
+      if (r->next != NULL) {
+        prev = r;
+      }
+      r = r->next;
+    }
+    if (oldest != NULL) {
+      pbufs_freed_current = ip_reass_free_complete_datagram(oldest, prev);
+      pbufs_freed += pbufs_freed_current;
+    }
+  } while ((pbufs_freed < pbufs_needed) && (other_datagrams > 1));
+  return pbufs_freed;
+}
+#endif /* IP_REASS_FREE_OLDEST */
+
+/**
+ * Enqueues a new fragment into the fragment queue
+ * @param fraghdr points to the new fragments IP hdr
+ * @param clen number of pbufs needed to enqueue (used for freeing other datagrams if not enough space)
+ * @return A pointer to the queue location into which the fragment was enqueued
+ */
+static struct ip_reassdata*
+ip_reass_enqueue_new_datagram(struct ip_hdr *fraghdr, int clen)
+{
+  struct ip_reassdata* ipr;
+  /* No matching previous fragment found, allocate a new reassdata struct */
+  ipr = (struct ip_reassdata *)memp_malloc(MEMP_REASSDATA);
+  if (ipr == NULL) {
+#if IP_REASS_FREE_OLDEST
+    if (ip_reass_remove_oldest_datagram(fraghdr, clen) >= clen) {
+      ipr = (struct ip_reassdata *)memp_malloc(MEMP_REASSDATA);
+    }
+    if (ipr == NULL)
+#endif /* IP_REASS_FREE_OLDEST */
+    {
+      IPFRAG_STATS_INC(ip_frag.memerr);
+      LWIP_DEBUGF(IP_REASS_DEBUG,("Failed to alloc reassdata struct\n"));
+      return NULL;
+    }
+  }
+  memset(ipr, 0, sizeof(struct ip_reassdata));
+  ipr->timer = IP_REASS_MAXAGE;
+
+  /* enqueue the new structure to the front of the list */
+  ipr->next = reassdatagrams;
+  reassdatagrams = ipr;
+  /* copy the ip header for later tests and input */
+  /* @todo: no ip options supported? */
+  SMEMCPY(&(ipr->iphdr), fraghdr, IP_HLEN);
+  return ipr;
+}
+
+/**
+ * Dequeues a datagram from the datagram queue. Doesn't deallocate the pbufs.
+ * @param ipr points to the queue entry to dequeue
+ */
+static void
+ip_reass_dequeue_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev)
+{
+  
+  /* dequeue the reass struct  */
+  if (reassdatagrams == ipr) {
+    /* it was the first in the list */
+    reassdatagrams = ipr->next;
+  } else {
+    /* it wasn't the first, so it must have a valid 'prev' */
+    LWIP_ASSERT("sanity check linked list", prev != NULL);
+    prev->next = ipr->next;
+  }
+
+  /* now we can free the ip_reass struct */
+  memp_free(MEMP_REASSDATA, ipr);
+}
+
+/**
+ * Chain a new pbuf into the pbuf list that composes the datagram.  The pbuf list
+ * will grow over time as  new pbufs are rx.
+ * Also checks that the datagram passes basic continuity checks (if the last
+ * fragment was received at least once).
+ * @param root_p points to the 'root' pbuf for the current datagram being assembled.
+ * @param new_p points to the pbuf for the current fragment
+ * @return 0 if invalid, >0 otherwise
+ */
+static int
+ip_reass_chain_frag_into_datagram_and_validate(struct ip_reassdata *ipr, struct pbuf *new_p)
+{
+  struct ip_reass_helper *iprh, *iprh_tmp, *iprh_prev=NULL;
+  struct pbuf *q;
+  u16_t offset,len;
+  struct ip_hdr *fraghdr;
+  int valid = 1;
+
+  /* Extract length and fragment offset from current fragment */
+  fraghdr = (struct ip_hdr*)new_p->payload; 
+  len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
+  offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
+
+  /* overwrite the fragment's ip header from the pbuf with our helper struct,
+   * and setup the embedded helper structure. */
+  /* make sure the struct ip_reass_helper fits into the IP header */
+  LWIP_ASSERT("sizeof(struct ip_reass_helper) <= IP_HLEN",
+              sizeof(struct ip_reass_helper) <= IP_HLEN);
+  iprh = (struct ip_reass_helper*)new_p->payload;
+  iprh->next_pbuf = NULL;
+  iprh->start = offset;
+  iprh->end = offset + len;
+
+  /* Iterate through until we either get to the end of the list (append),
+   * or we find on with a larger offset (insert). */
+  for (q = ipr->p; q != NULL;) {
+    iprh_tmp = (struct ip_reass_helper*)q->payload;
+    if (iprh->start < iprh_tmp->start) {
+      /* the new pbuf should be inserted before this */
+      iprh->next_pbuf = q;
+      if (iprh_prev != NULL) {
+        /* not the fragment with the lowest offset */
+#if IP_REASS_CHECK_OVERLAP
+        if ((iprh->start < iprh_prev->end) || (iprh->end > iprh_tmp->start)) {
+          /* fragment overlaps with previous or following, throw away */
+          goto freepbuf;
+        }
+#endif /* IP_REASS_CHECK_OVERLAP */
+        iprh_prev->next_pbuf = new_p;
+      } else {
+        /* fragment with the lowest offset */
+        ipr->p = new_p;
+      }
+      break;
+    } else if(iprh->start == iprh_tmp->start) {
+      /* received the same datagram twice: no need to keep the datagram */
+      goto freepbuf;
+#if IP_REASS_CHECK_OVERLAP
+    } else if(iprh->start < iprh_tmp->end) {
+      /* overlap: no need to keep the new datagram */
+      goto freepbuf;
+#endif /* IP_REASS_CHECK_OVERLAP */
+    } else {
+      /* Check if the fragments received so far have no wholes. */
+      if (iprh_prev != NULL) {
+        if (iprh_prev->end != iprh_tmp->start) {
+          /* There is a fragment missing between the current
+           * and the previous fragment */
+          valid = 0;
+        }
+      }
+    }
+    q = iprh_tmp->next_pbuf;
+    iprh_prev = iprh_tmp;
+  }
+
+  /* If q is NULL, then we made it to the end of the list. Determine what to do now */
+  if (q == NULL) {
+    if (iprh_prev != NULL) {
+      /* this is (for now), the fragment with the highest offset:
+       * chain it to the last fragment */
+#if IP_REASS_CHECK_OVERLAP
+      LWIP_ASSERT("check fragments don't overlap", iprh_prev->end <= iprh->start);
+#endif /* IP_REASS_CHECK_OVERLAP */
+      iprh_prev->next_pbuf = new_p;
+      if (iprh_prev->end != iprh->start) {
+        valid = 0;
+      }
+    } else {
+#if IP_REASS_CHECK_OVERLAP
+      LWIP_ASSERT("no previous fragment, this must be the first fragment!",
+        ipr->p == NULL);
+#endif /* IP_REASS_CHECK_OVERLAP */
+      /* this is the first fragment we ever received for this ip datagram */
+      ipr->p = new_p;
+    }
+  }
+
+  /* At this point, the validation part begins: */
+  /* If we already received the last fragment */
+  if ((ipr->flags & IP_REASS_FLAG_LASTFRAG) != 0) {
+    /* and had no wholes so far */
+    if (valid) {
+      /* then check if the rest of the fragments is here */
+      /* Check if the queue starts with the first datagram */
+      if (((struct ip_reass_helper*)ipr->p->payload)->start != 0) {
+        valid = 0;
+      } else {
+        /* and check that there are no wholes after this datagram */
+        iprh_prev = iprh;
+        q = iprh->next_pbuf;
+        while (q != NULL) {
+          iprh = (struct ip_reass_helper*)q->payload;
+          if (iprh_prev->end != iprh->start) {
+            valid = 0;
+            break;
+          }
+          iprh_prev = iprh;
+          q = iprh->next_pbuf;
+        }
+        /* if still valid, all fragments are received
+         * (because to the MF==0 already arrived */
+        if (valid) {
+          LWIP_ASSERT("sanity check", ipr->p != NULL);
+          LWIP_ASSERT("sanity check",
+            ((struct ip_reass_helper*)ipr->p->payload) != iprh);
+          LWIP_ASSERT("validate_datagram:next_pbuf!=NULL",
+            iprh->next_pbuf == NULL);
+          LWIP_ASSERT("validate_datagram:datagram end!=datagram len",
+            iprh->end == ipr->datagram_len);
+        }
+      }
+    }
+    /* If valid is 0 here, there are some fragments missing in the middle
+     * (since MF == 0 has already arrived). Such datagrams simply time out if
+     * no more fragments are received... */
+    return valid;
+  }
+  /* If we come here, not all fragments were received, yet! */
+  return 0; /* not yet valid! */
+#if IP_REASS_CHECK_OVERLAP
+freepbuf:
+  ip_reass_pbufcount -= pbuf_clen(new_p);
+  pbuf_free(new_p);
+  return 0;
+#endif /* IP_REASS_CHECK_OVERLAP */
+}
+
+/**
+ * Reassembles incoming IP fragments into an IP datagram.
+ *
+ * @param p points to a pbuf chain of the fragment
+ * @return NULL if reassembly is incomplete, ? otherwise
+ */
+struct pbuf *
+ip_reass(struct pbuf *p)
+{
+  struct pbuf *r;
+  struct ip_hdr *fraghdr;
+  struct ip_reassdata *ipr;
+  struct ip_reass_helper *iprh;
+  u16_t offset, len;
+  u8_t clen;
+  struct ip_reassdata *ipr_prev = NULL;
+
+  IPFRAG_STATS_INC(ip_frag.recv);
+  snmp_inc_ipreasmreqds();
+
+  fraghdr = (struct ip_hdr*)p->payload;
+
+  if ((IPH_HL(fraghdr) * 4) != IP_HLEN) {
+    LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: IP options currently not supported!\n"));
+    IPFRAG_STATS_INC(ip_frag.err);
+    goto nullreturn;
+  }
+
+  offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
+  len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
+
+  /* Check if we are allowed to enqueue more datagrams. */
+  clen = pbuf_clen(p);
+  if ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) {
+#if IP_REASS_FREE_OLDEST
+    if (!ip_reass_remove_oldest_datagram(fraghdr, clen) ||
+        ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS))
+#endif /* IP_REASS_FREE_OLDEST */
+    {
+      /* No datagram could be freed and still too many pbufs enqueued */
+      LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: Overflow condition: pbufct=%d, clen=%d, MAX=%d\n",
+        ip_reass_pbufcount, clen, IP_REASS_MAX_PBUFS));
+      IPFRAG_STATS_INC(ip_frag.memerr);
+      /* @todo: send ICMP time exceeded here? */
+      /* drop this pbuf */
+      goto nullreturn;
+    }
+  }
+
+  /* Look for the datagram the fragment belongs to in the current datagram queue,
+   * remembering the previous in the queue for later dequeueing. */
+  for (ipr = reassdatagrams; ipr != NULL; ipr = ipr->next) {
+    /* Check if the incoming fragment matches the one currently present
+       in the reassembly buffer. If so, we proceed with copying the
+       fragment into the buffer. */
+    if (IP_ADDRESSES_AND_ID_MATCH(&ipr->iphdr, fraghdr)) {
+      LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: matching previous fragment ID=%"X16_F"\n",
+        ntohs(IPH_ID(fraghdr))));
+      IPFRAG_STATS_INC(ip_frag.cachehit);
+      break;
+    }
+    ipr_prev = ipr;
+  }
+
+  if (ipr == NULL) {
+  /* Enqueue a new datagram into the datagram queue */
+    ipr = ip_reass_enqueue_new_datagram(fraghdr, clen);
+    /* Bail if unable to enqueue */
+    if(ipr == NULL) {
+      goto nullreturn;
+    }
+  } else {
+    if (((ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) == 0) && 
+      ((ntohs(IPH_OFFSET(&ipr->iphdr)) & IP_OFFMASK) != 0)) {
+      /* ipr->iphdr is not the header from the first fragment, but fraghdr is
+       * -> copy fraghdr into ipr->iphdr since we want to have the header
+       * of the first fragment (for ICMP time exceeded and later, for copying
+       * all options, if supported)*/
+      SMEMCPY(&ipr->iphdr, fraghdr, IP_HLEN);
+    }
+  }
+  /* Track the current number of pbufs current 'in-flight', in order to limit 
+  the number of fragments that may be enqueued at any one time */
+  ip_reass_pbufcount += clen;
+
+  /* At this point, we have either created a new entry or pointing 
+   * to an existing one */
+
+  /* check for 'no more fragments', and update queue entry*/
+  if ((IPH_OFFSET(fraghdr) & PP_NTOHS(IP_MF)) == 0) {
+    ipr->flags |= IP_REASS_FLAG_LASTFRAG;
+    ipr->datagram_len = offset + len;
+    LWIP_DEBUGF(IP_REASS_DEBUG,
+     ("ip_reass: last fragment seen, total len %"S16_F"\n",
+      ipr->datagram_len));
+  }
+  /* find the right place to insert this pbuf */
+  /* @todo: trim pbufs if fragments are overlapping */
+  if (ip_reass_chain_frag_into_datagram_and_validate(ipr, p)) {
+    /* the totally last fragment (flag more fragments = 0) was received at least
+     * once AND all fragments are received */
+    ipr->datagram_len += IP_HLEN;
+
+    /* save the second pbuf before copying the header over the pointer */
+    r = ((struct ip_reass_helper*)ipr->p->payload)->next_pbuf;
+
+    /* copy the original ip header back to the first pbuf */
+    fraghdr = (struct ip_hdr*)(ipr->p->payload);
+    SMEMCPY(fraghdr, &ipr->iphdr, IP_HLEN);
+    IPH_LEN_SET(fraghdr, htons(ipr->datagram_len));
+    IPH_OFFSET_SET(fraghdr, 0);
+    IPH_CHKSUM_SET(fraghdr, 0);
+    /* @todo: do we need to set calculate the correct checksum? */
+    IPH_CHKSUM_SET(fraghdr, inet_chksum(fraghdr, IP_HLEN));
+
+    p = ipr->p;
+
+    /* chain together the pbufs contained within the reass_data list. */
+    while(r != NULL) {
+      iprh = (struct ip_reass_helper*)r->payload;
+
+      /* hide the ip header for every succeding fragment */
+      pbuf_header(r, -IP_HLEN);
+      pbuf_cat(p, r);
+      r = iprh->next_pbuf;
+    }
+    /* release the sources allocate for the fragment queue entry */
+    ip_reass_dequeue_datagram(ipr, ipr_prev);
+
+    /* and adjust the number of pbufs currently queued for reassembly. */
+    ip_reass_pbufcount -= pbuf_clen(p);
+
+    /* Return the pbuf chain */
+    return p;
+  }
+  /* the datagram is not (yet?) reassembled completely */
+  LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass_pbufcount: %d out\n", ip_reass_pbufcount));
+  return NULL;
+
+nullreturn:
+  LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: nullreturn\n"));
+  IPFRAG_STATS_INC(ip_frag.drop);
+  pbuf_free(p);
+  return NULL;
+}
+#endif /* IP_REASSEMBLY */
+
+#if IP_FRAG
+#if IP_FRAG_USES_STATIC_BUF
+static u8_t buf[LWIP_MEM_ALIGN_SIZE(IP_FRAG_MAX_MTU + MEM_ALIGNMENT - 1)];
+#else /* IP_FRAG_USES_STATIC_BUF */
+
+#if !LWIP_NETIF_TX_SINGLE_PBUF
+/** Allocate a new struct pbuf_custom_ref */
+static struct pbuf_custom_ref*
+ip_frag_alloc_pbuf_custom_ref(void)
+{
+  return (struct pbuf_custom_ref*)memp_malloc(MEMP_FRAG_PBUF);
+}
+
+/** Free a struct pbuf_custom_ref */
+static void
+ip_frag_free_pbuf_custom_ref(struct pbuf_custom_ref* p)
+{
+  LWIP_ASSERT("p != NULL", p != NULL);
+  memp_free(MEMP_FRAG_PBUF, p);
+}
+
+/** Free-callback function to free a 'struct pbuf_custom_ref', called by
+ * pbuf_free. */
+static void
+ipfrag_free_pbuf_custom(struct pbuf *p)
+{
+  struct pbuf_custom_ref *pcr = (struct pbuf_custom_ref*)p;
+  LWIP_ASSERT("pcr != NULL", pcr != NULL);
+  LWIP_ASSERT("pcr == p", (void*)pcr == (void*)p);
+  if (pcr->original != NULL) {
+    pbuf_free(pcr->original);
+  }
+  ip_frag_free_pbuf_custom_ref(pcr);
+}
+#endif /* !LWIP_NETIF_TX_SINGLE_PBUF */
+#endif /* IP_FRAG_USES_STATIC_BUF */
+
+/**
+ * Fragment an IP datagram if too large for the netif.
+ *
+ * Chop the datagram in MTU sized chunks and send them in order
+ * by using a fixed size static memory buffer (PBUF_REF) or
+ * point PBUF_REFs into p (depending on IP_FRAG_USES_STATIC_BUF).
+ *
+ * @param p ip packet to send
+ * @param netif the netif on which to send
+ * @param dest destination ip address to which to send
+ *
+ * @return ERR_OK if sent successfully, err_t otherwise
+ */
+err_t 
+ip_frag(struct pbuf *p, struct netif *netif, ip_addr_t *dest)
+{
+  struct pbuf *rambuf;
+#if IP_FRAG_USES_STATIC_BUF
+  struct pbuf *header;
+#else
+#if !LWIP_NETIF_TX_SINGLE_PBUF
+  struct pbuf *newpbuf;
+#endif
+  struct ip_hdr *original_iphdr;
+#endif
+  struct ip_hdr *iphdr;
+  u16_t nfb;
+  u16_t left, cop;
+  u16_t mtu = netif->mtu;
+  u16_t ofo, omf;
+  u16_t last;
+  u16_t poff = IP_HLEN;
+  u16_t tmp;
+#if !IP_FRAG_USES_STATIC_BUF && !LWIP_NETIF_TX_SINGLE_PBUF
+  u16_t newpbuflen = 0;
+  u16_t left_to_copy;
+#endif
+
+  /* Get a RAM based MTU sized pbuf */
+#if IP_FRAG_USES_STATIC_BUF
+  /* When using a static buffer, we use a PBUF_REF, which we will
+   * use to reference the packet (without link header).
+   * Layer and length is irrelevant.
+   */
+  rambuf = pbuf_alloc(PBUF_LINK, 0, PBUF_REF);
+  if (rambuf == NULL) {
+    LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc(PBUF_LINK, 0, PBUF_REF) failed\n"));
+    return ERR_MEM;
+  }
+  rambuf->tot_len = rambuf->len = mtu;
+  rambuf->payload = LWIP_MEM_ALIGN((void *)buf);
+
+  /* Copy the IP header in it */
+  iphdr = (struct ip_hdr *)rambuf->payload;
+  SMEMCPY(iphdr, p->payload, IP_HLEN);
+#else /* IP_FRAG_USES_STATIC_BUF */
+  original_iphdr = (struct ip_hdr *)p->payload;
+  iphdr = original_iphdr;
+#endif /* IP_FRAG_USES_STATIC_BUF */
+
+  /* Save original offset */
+  tmp = ntohs(IPH_OFFSET(iphdr));
+  ofo = tmp & IP_OFFMASK;
+  omf = tmp & IP_MF;
+
+  left = p->tot_len - IP_HLEN;
+
+  nfb = (mtu - IP_HLEN) / 8;
+
+  while (left) {
+    last = (left <= mtu - IP_HLEN);
+
+    /* Set new offset and MF flag */
+    tmp = omf | (IP_OFFMASK & (ofo));
+    if (!last) {
+      tmp = tmp | IP_MF;
+    }
+
+    /* Fill this fragment */
+    cop = last ? left : nfb * 8;
+
+#if IP_FRAG_USES_STATIC_BUF
+    poff += pbuf_copy_partial(p, (u8_t*)iphdr + IP_HLEN, cop, poff);
+#else /* IP_FRAG_USES_STATIC_BUF */
+#if LWIP_NETIF_TX_SINGLE_PBUF
+    rambuf = pbuf_alloc(PBUF_IP, cop, PBUF_RAM);
+    if (rambuf == NULL) {
+      return ERR_MEM;
+    }
+    LWIP_ASSERT("this needs a pbuf in one piece!",
+      (rambuf->len == rambuf->tot_len) && (rambuf->next == NULL));
+    poff += pbuf_copy_partial(p, rambuf->payload, cop, poff);
+    /* make room for the IP header */
+    if(pbuf_header(rambuf, IP_HLEN)) {
+      pbuf_free(rambuf);
+      return ERR_MEM;
+    }
+    /* fill in the IP header */
+    SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
+    iphdr = rambuf->payload;
+#else /* LWIP_NETIF_TX_SINGLE_PBUF */
+    /* When not using a static buffer, create a chain of pbufs.
+     * The first will be a PBUF_RAM holding the link and IP header.
+     * The rest will be PBUF_REFs mirroring the pbuf chain to be fragged,
+     * but limited to the size of an mtu.
+     */
+    rambuf = pbuf_alloc(PBUF_LINK, IP_HLEN, PBUF_RAM);
+    if (rambuf == NULL) {
+      return ERR_MEM;
+    }
+    LWIP_ASSERT("this needs a pbuf in one piece!",
+                (p->len >= (IP_HLEN)));
+    SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
+    iphdr = (struct ip_hdr *)rambuf->payload;
+
+    /* Can just adjust p directly for needed offset. */
+    p->payload = (u8_t *)p->payload + poff;
+    p->len -= poff;
+
+    left_to_copy = cop;
+    while (left_to_copy) {
+      struct pbuf_custom_ref *pcr;
+      newpbuflen = (left_to_copy < p->len) ? left_to_copy : p->len;
+      /* Is this pbuf already empty? */
+      if (!newpbuflen) {
+        p = p->next;
+        continue;
+      }
+      pcr = ip_frag_alloc_pbuf_custom_ref();
+      if (pcr == NULL) {
+        pbuf_free(rambuf);
+        return ERR_MEM;
+      }
+      /* Mirror this pbuf, although we might not need all of it. */
+      newpbuf = pbuf_alloced_custom(PBUF_RAW, newpbuflen, PBUF_REF, &pcr->pc, p->payload, newpbuflen);
+      if (newpbuf == NULL) {
+        ip_frag_free_pbuf_custom_ref(pcr);
+        pbuf_free(rambuf);
+        return ERR_MEM;
+      }
+      pbuf_ref(p);
+      pcr->original = p;
+      pcr->pc.custom_free_function = ipfrag_free_pbuf_custom;
+
+      /* Add it to end of rambuf's chain, but using pbuf_cat, not pbuf_chain
+       * so that it is removed when pbuf_dechain is later called on rambuf.
+       */
+      pbuf_cat(rambuf, newpbuf);
+      left_to_copy -= newpbuflen;
+      if (left_to_copy) {
+        p = p->next;
+      }
+    }
+    poff = newpbuflen;
+#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
+#endif /* IP_FRAG_USES_STATIC_BUF */
+
+    /* Correct header */
+    IPH_OFFSET_SET(iphdr, htons(tmp));
+    IPH_LEN_SET(iphdr, htons(cop + IP_HLEN));
+    IPH_CHKSUM_SET(iphdr, 0);
+    IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
+
+#if IP_FRAG_USES_STATIC_BUF
+    if (last) {
+      pbuf_realloc(rambuf, left + IP_HLEN);
+    }
+
+    /* This part is ugly: we alloc a RAM based pbuf for 
+     * the link level header for each chunk and then 
+     * free it.A PBUF_ROM style pbuf for which pbuf_header
+     * worked would make things simpler.
+     */
+    header = pbuf_alloc(PBUF_LINK, 0, PBUF_RAM);
+    if (header != NULL) {
+      pbuf_chain(header, rambuf);
+      netif->output(netif, header, dest);
+      IPFRAG_STATS_INC(ip_frag.xmit);
+      snmp_inc_ipfragcreates();
+      pbuf_free(header);
+    } else {
+      LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc() for header failed\n"));
+      pbuf_free(rambuf);
+      return ERR_MEM;
+    }
+#else /* IP_FRAG_USES_STATIC_BUF */
+    /* No need for separate header pbuf - we allowed room for it in rambuf
+     * when allocated.
+     */
+    netif->output(netif, rambuf, dest);
+    IPFRAG_STATS_INC(ip_frag.xmit);
+
+    /* Unfortunately we can't reuse rambuf - the hardware may still be
+     * using the buffer. Instead we free it (and the ensuing chain) and
+     * recreate it next time round the loop. If we're lucky the hardware
+     * will have already sent the packet, the free will really free, and
+     * there will be zero memory penalty.
+     */
+    
+    pbuf_free(rambuf);
+#endif /* IP_FRAG_USES_STATIC_BUF */
+    left -= cop;
+    ofo += nfb;
+  }
+#if IP_FRAG_USES_STATIC_BUF
+  pbuf_free(rambuf);
+#endif /* IP_FRAG_USES_STATIC_BUF */
+  snmp_inc_ipfragoks();
+  return ERR_OK;
+}
+#endif /* IP_FRAG */
diff --git a/core/lwip/src/core/mem.c b/core/lwip/src/core/mem.c
new file mode 100644
index 00000000..2934e5a9
--- /dev/null
+++ b/core/lwip/src/core/mem.c
@@ -0,0 +1,642 @@
+/**
+ * @file
+ * Dynamic memory manager
+ *
+ * This is a lightweight replacement for the standard C library malloc().
+ *
+ * If you want to use the standard C library malloc() instead, define
+ * MEM_LIBC_MALLOC to 1 in your lwipopts.h
+ *
+ * To let mem_malloc() use pools (prevents fragmentation and is much faster than
+ * a heap but might waste some memory), define MEM_USE_POOLS to 1, define
+ * MEM_USE_CUSTOM_POOLS to 1 and create a file "lwippools.h" that includes a list
+ * of pools like this (more pools can be added between _START and _END):
+ *
+ * Define three pools with sizes 256, 512, and 1512 bytes
+ * LWIP_MALLOC_MEMPOOL_START
+ * LWIP_MALLOC_MEMPOOL(20, 256)
+ * LWIP_MALLOC_MEMPOOL(10, 512)
+ * LWIP_MALLOC_MEMPOOL(5, 1512)
+ * LWIP_MALLOC_MEMPOOL_END
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *         Simon Goldschmidt
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if !MEM_LIBC_MALLOC /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/def.h"
+#include "lwip/mem.h"
+#include "lwip/sys.h"
+#include "lwip/stats.h"
+#include "lwip/err.h"
+
+#include <string.h>
+
+#if MEM_USE_POOLS
+/* lwIP head implemented with different sized pools */
+
+/**
+ * Allocate memory: determine the smallest pool that is big enough
+ * to contain an element of 'size' and get an element from that pool.
+ *
+ * @param size the size in bytes of the memory needed
+ * @return a pointer to the allocated memory or NULL if the pool is empty
+ */
+void *
+mem_malloc(mem_size_t size)
+{
+  struct memp_malloc_helper *element;
+  memp_t poolnr;
+  mem_size_t required_size = size + sizeof(struct memp_malloc_helper);
+
+  for (poolnr = MEMP_POOL_FIRST; poolnr <= MEMP_POOL_LAST; poolnr = (memp_t)(poolnr + 1)) {
+#if MEM_USE_POOLS_TRY_BIGGER_POOL
+again:
+#endif /* MEM_USE_POOLS_TRY_BIGGER_POOL */
+    /* is this pool big enough to hold an element of the required size
+       plus a struct memp_malloc_helper that saves the pool this element came from? */
+    if (required_size <= memp_sizes[poolnr]) {
+      break;
+    }
+  }
+  if (poolnr > MEMP_POOL_LAST) {
+    LWIP_ASSERT("mem_malloc(): no pool is that big!", 0);
+    return NULL;
+  }
+  element = (struct memp_malloc_helper*)memp_malloc(poolnr);
+  if (element == NULL) {
+    /* No need to DEBUGF or ASSERT: This error is already
+       taken care of in memp.c */
+#if MEM_USE_POOLS_TRY_BIGGER_POOL
+    /** Try a bigger pool if this one is empty! */
+    if (poolnr < MEMP_POOL_LAST) {
+      poolnr++;
+      goto again;
+    }
+#endif /* MEM_USE_POOLS_TRY_BIGGER_POOL */
+    return NULL;
+  }
+
+  /* save the pool number this element came from */
+  element->poolnr = poolnr;
+  /* and return a pointer to the memory directly after the struct memp_malloc_helper */
+  element++;
+
+  return element;
+}
+
+/**
+ * Free memory previously allocated by mem_malloc. Loads the pool number
+ * and calls memp_free with that pool number to put the element back into
+ * its pool
+ *
+ * @param rmem the memory element to free
+ */
+void
+mem_free(void *rmem)
+{
+  struct memp_malloc_helper *hmem = (struct memp_malloc_helper*)rmem;
+
+  LWIP_ASSERT("rmem != NULL", (rmem != NULL));
+  LWIP_ASSERT("rmem == MEM_ALIGN(rmem)", (rmem == LWIP_MEM_ALIGN(rmem)));
+
+  /* get the original struct memp_malloc_helper */
+  hmem--;
+
+  LWIP_ASSERT("hmem != NULL", (hmem != NULL));
+  LWIP_ASSERT("hmem == MEM_ALIGN(hmem)", (hmem == LWIP_MEM_ALIGN(hmem)));
+  LWIP_ASSERT("hmem->poolnr < MEMP_MAX", (hmem->poolnr < MEMP_MAX));
+
+  /* and put it in the pool we saved earlier */
+  memp_free(hmem->poolnr, hmem);
+}
+
+#else /* MEM_USE_POOLS */
+/* lwIP replacement for your libc malloc() */
+
+/**
+ * The heap is made up as a list of structs of this type.
+ * This does not have to be aligned since for getting its size,
+ * we only use the macro SIZEOF_STRUCT_MEM, which automatically alignes.
+ */
+struct mem {
+  /** index (-> ram[next]) of the next struct */
+  mem_size_t next;
+  /** index (-> ram[prev]) of the previous struct */
+  mem_size_t prev;
+  /** 1: this area is used; 0: this area is unused */
+  u8_t used;
+};
+
+/** All allocated blocks will be MIN_SIZE bytes big, at least!
+ * MIN_SIZE can be overridden to suit your needs. Smaller values save space,
+ * larger values could prevent too small blocks to fragment the RAM too much. */
+#ifndef MIN_SIZE
+#define MIN_SIZE             12
+#endif /* MIN_SIZE */
+/* some alignment macros: we define them here for better source code layout */
+#define MIN_SIZE_ALIGNED     LWIP_MEM_ALIGN_SIZE(MIN_SIZE)
+#define SIZEOF_STRUCT_MEM    LWIP_MEM_ALIGN_SIZE(sizeof(struct mem))
+#define MEM_SIZE_ALIGNED     LWIP_MEM_ALIGN_SIZE(MEM_SIZE)
+
+/** If you want to relocate the heap to external memory, simply define
+ * LWIP_RAM_HEAP_POINTER as a void-pointer to that location.
+ * If so, make sure the memory at that location is big enough (see below on
+ * how that space is calculated). */
+#ifndef LWIP_RAM_HEAP_POINTER
+/** the heap. we need one struct mem at the end and some room for alignment */
+u8_t ram_heap[MEM_SIZE_ALIGNED + (2*SIZEOF_STRUCT_MEM) + MEM_ALIGNMENT];
+#define LWIP_RAM_HEAP_POINTER ram_heap
+#endif /* LWIP_RAM_HEAP_POINTER */
+
+/** pointer to the heap (ram_heap): for alignment, ram is now a pointer instead of an array */
+static u8_t *ram;
+/** the last entry, always unused! */
+static struct mem *ram_end;
+/** pointer to the lowest free block, this is used for faster search */
+static struct mem *lfree;
+
+/** concurrent access protection */
+static sys_mutex_t mem_mutex;
+
+#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT
+
+static volatile u8_t mem_free_count;
+
+/* Allow mem_free from other (e.g. interrupt) context */
+#define LWIP_MEM_FREE_DECL_PROTECT()  SYS_ARCH_DECL_PROTECT(lev_free)
+#define LWIP_MEM_FREE_PROTECT()       SYS_ARCH_PROTECT(lev_free)
+#define LWIP_MEM_FREE_UNPROTECT()     SYS_ARCH_UNPROTECT(lev_free)
+#define LWIP_MEM_ALLOC_DECL_PROTECT() SYS_ARCH_DECL_PROTECT(lev_alloc)
+#define LWIP_MEM_ALLOC_PROTECT()      SYS_ARCH_PROTECT(lev_alloc)
+#define LWIP_MEM_ALLOC_UNPROTECT()    SYS_ARCH_UNPROTECT(lev_alloc)
+
+#else /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */
+
+/* Protect the heap only by using a semaphore */
+#define LWIP_MEM_FREE_DECL_PROTECT()
+#define LWIP_MEM_FREE_PROTECT()    sys_mutex_lock(&mem_mutex)
+#define LWIP_MEM_FREE_UNPROTECT()  sys_mutex_unlock(&mem_mutex)
+/* mem_malloc is protected using semaphore AND LWIP_MEM_ALLOC_PROTECT */
+#define LWIP_MEM_ALLOC_DECL_PROTECT()
+#define LWIP_MEM_ALLOC_PROTECT()
+#define LWIP_MEM_ALLOC_UNPROTECT()
+
+#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */
+
+
+/**
+ * "Plug holes" by combining adjacent empty struct mems.
+ * After this function is through, there should not exist
+ * one empty struct mem pointing to another empty struct mem.
+ *
+ * @param mem this points to a struct mem which just has been freed
+ * @internal this function is only called by mem_free() and mem_trim()
+ *
+ * This assumes access to the heap is protected by the calling function
+ * already.
+ */
+static void
+plug_holes(struct mem *mem)
+{
+  struct mem *nmem;
+  struct mem *pmem;
+
+  LWIP_ASSERT("plug_holes: mem >= ram", (u8_t *)mem >= ram);
+  LWIP_ASSERT("plug_holes: mem < ram_end", (u8_t *)mem < (u8_t *)ram_end);
+  LWIP_ASSERT("plug_holes: mem->used == 0", mem->used == 0);
+
+  /* plug hole forward */
+  LWIP_ASSERT("plug_holes: mem->next <= MEM_SIZE_ALIGNED", mem->next <= MEM_SIZE_ALIGNED);
+
+  nmem = (struct mem *)(void *)&ram[mem->next];
+  if (mem != nmem && nmem->used == 0 && (u8_t *)nmem != (u8_t *)ram_end) {
+    /* if mem->next is unused and not end of ram, combine mem and mem->next */
+    if (lfree == nmem) {
+      lfree = mem;
+    }
+    mem->next = nmem->next;
+    ((struct mem *)(void *)&ram[nmem->next])->prev = (mem_size_t)((u8_t *)mem - ram);
+  }
+
+  /* plug hole backward */
+  pmem = (struct mem *)(void *)&ram[mem->prev];
+  if (pmem != mem && pmem->used == 0) {
+    /* if mem->prev is unused, combine mem and mem->prev */
+    if (lfree == mem) {
+      lfree = pmem;
+    }
+    pmem->next = mem->next;
+    ((struct mem *)(void *)&ram[mem->next])->prev = (mem_size_t)((u8_t *)pmem - ram);
+  }
+}
+
+/**
+ * Zero the heap and initialize start, end and lowest-free
+ */
+void
+lwip_mem_init(void)
+{
+  struct mem *mem;
+
+  LWIP_ASSERT("Sanity check alignment",
+    (SIZEOF_STRUCT_MEM & (MEM_ALIGNMENT-1)) == 0);
+
+  /* align the heap */
+  ram = (u8_t *)LWIP_MEM_ALIGN(LWIP_RAM_HEAP_POINTER);
+  /* initialize the start of the heap */
+  mem = (struct mem *)(void *)ram;
+  mem->next = MEM_SIZE_ALIGNED;
+  mem->prev = 0;
+  mem->used = 0;
+  /* initialize the end of the heap */
+  ram_end = (struct mem *)(void *)&ram[MEM_SIZE_ALIGNED];
+  ram_end->used = 1;
+  ram_end->next = MEM_SIZE_ALIGNED;
+  ram_end->prev = MEM_SIZE_ALIGNED;
+
+  /* initialize the lowest-free pointer to the start of the heap */
+  lfree = (struct mem *)(void *)ram;
+
+  MEM_STATS_AVAIL(avail, MEM_SIZE_ALIGNED);
+
+  if(sys_mutex_new(&mem_mutex) != ERR_OK) {
+    LWIP_ASSERT("failed to create mem_mutex", 0);
+  }
+}
+
+/**
+ * Put a struct mem back on the heap
+ *
+ * @param rmem is the data portion of a struct mem as returned by a previous
+ *             call to mem_malloc()
+ */
+void
+mem_free(void *rmem)
+{
+  struct mem *mem;
+  LWIP_MEM_FREE_DECL_PROTECT();
+
+  if (rmem == NULL) {
+    LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("mem_free(p == NULL) was called.\n"));
+    return;
+  }
+  LWIP_ASSERT("mem_free: sanity check alignment", (((mem_ptr_t)rmem) & (MEM_ALIGNMENT-1)) == 0);
+
+  LWIP_ASSERT("mem_free: legal memory", (u8_t *)rmem >= (u8_t *)ram &&
+    (u8_t *)rmem < (u8_t *)ram_end);
+
+  if ((u8_t *)rmem < (u8_t *)ram || (u8_t *)rmem >= (u8_t *)ram_end) {
+    SYS_ARCH_DECL_PROTECT(lev);
+    LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_LEVEL_SEVERE, ("mem_free: illegal memory\n"));
+    /* protect mem stats from concurrent access */
+    SYS_ARCH_PROTECT(lev);
+    MEM_STATS_INC(illegal);
+    SYS_ARCH_UNPROTECT(lev);
+    return;
+  }
+  /* protect the heap from concurrent access */
+  LWIP_MEM_FREE_PROTECT();
+  /* Get the corresponding struct mem ... */
+  mem = (struct mem *)(void *)((u8_t *)rmem - SIZEOF_STRUCT_MEM);
+  /* ... which has to be in a used state ... */
+  LWIP_ASSERT("mem_free: mem->used", mem->used);
+  /* ... and is now unused. */
+  mem->used = 0;
+
+  if (mem < lfree) {
+    /* the newly freed struct is now the lowest */
+    lfree = mem;
+  }
+
+  MEM_STATS_DEC_USED(used, mem->next - (mem_size_t)(((u8_t *)mem - ram)));
+
+  /* finally, see if prev or next are free also */
+  plug_holes(mem);
+#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT
+  mem_free_count = 1;
+#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */
+  LWIP_MEM_FREE_UNPROTECT();
+}
+
+/**
+ * Shrink memory returned by mem_malloc().
+ *
+ * @param rmem pointer to memory allocated by mem_malloc the is to be shrinked
+ * @param newsize required size after shrinking (needs to be smaller than or
+ *                equal to the previous size)
+ * @return for compatibility reasons: is always == rmem, at the moment
+ *         or NULL if newsize is > old size, in which case rmem is NOT touched
+ *         or freed!
+ */
+void *
+mem_trim(void *rmem, mem_size_t newsize)
+{
+  mem_size_t size;
+  mem_size_t ptr, ptr2;
+  struct mem *mem, *mem2;
+  /* use the FREE_PROTECT here: it protects with sem OR SYS_ARCH_PROTECT */
+  LWIP_MEM_FREE_DECL_PROTECT();
+
+  /* Expand the size of the allocated memory region so that we can
+     adjust for alignment. */
+  newsize = LWIP_MEM_ALIGN_SIZE(newsize);
+
+  if(newsize < MIN_SIZE_ALIGNED) {
+    /* every data block must be at least MIN_SIZE_ALIGNED long */
+    newsize = MIN_SIZE_ALIGNED;
+  }
+
+  if (newsize > MEM_SIZE_ALIGNED) {
+    return NULL;
+  }
+
+  LWIP_ASSERT("mem_trim: legal memory", (u8_t *)rmem >= (u8_t *)ram &&
+   (u8_t *)rmem < (u8_t *)ram_end);
+
+  if ((u8_t *)rmem < (u8_t *)ram || (u8_t *)rmem >= (u8_t *)ram_end) {
+    SYS_ARCH_DECL_PROTECT(lev);
+    LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_LEVEL_SEVERE, ("mem_trim: illegal memory\n"));
+    /* protect mem stats from concurrent access */
+    SYS_ARCH_PROTECT(lev);
+    MEM_STATS_INC(illegal);
+    SYS_ARCH_UNPROTECT(lev);
+    return rmem;
+  }
+  /* Get the corresponding struct mem ... */
+  mem = (struct mem *)(void *)((u8_t *)rmem - SIZEOF_STRUCT_MEM);
+  /* ... and its offset pointer */
+  ptr = (mem_size_t)((u8_t *)mem - ram);
+
+  size = mem->next - ptr - SIZEOF_STRUCT_MEM;
+  LWIP_ASSERT("mem_trim can only shrink memory", newsize <= size);
+  if (newsize > size) {
+    /* not supported */
+    return NULL;
+  }
+  if (newsize == size) {
+    /* No change in size, simply return */
+    return rmem;
+  }
+
+  /* protect the heap from concurrent access */
+  LWIP_MEM_FREE_PROTECT();
+
+  mem2 = (struct mem *)(void *)&ram[mem->next];
+  if(mem2->used == 0) {
+    /* The next struct is unused, we can simply move it at little */
+    mem_size_t next;
+    /* remember the old next pointer */
+    next = mem2->next;
+    /* create new struct mem which is moved directly after the shrinked mem */
+    ptr2 = ptr + SIZEOF_STRUCT_MEM + newsize;
+    if (lfree == mem2) {
+      lfree = (struct mem *)(void *)&ram[ptr2];
+    }
+    mem2 = (struct mem *)(void *)&ram[ptr2];
+    mem2->used = 0;
+    /* restore the next pointer */
+    mem2->next = next;
+    /* link it back to mem */
+    mem2->prev = ptr;
+    /* link mem to it */
+    mem->next = ptr2;
+    /* last thing to restore linked list: as we have moved mem2,
+     * let 'mem2->next->prev' point to mem2 again. but only if mem2->next is not
+     * the end of the heap */
+    if (mem2->next != MEM_SIZE_ALIGNED) {
+      ((struct mem *)(void *)&ram[mem2->next])->prev = ptr2;
+    }
+    MEM_STATS_DEC_USED(used, (size - newsize));
+    /* no need to plug holes, we've already done that */
+  } else if (newsize + SIZEOF_STRUCT_MEM + MIN_SIZE_ALIGNED <= size) {
+    /* Next struct is used but there's room for another struct mem with
+     * at least MIN_SIZE_ALIGNED of data.
+     * Old size ('size') must be big enough to contain at least 'newsize' plus a struct mem
+     * ('SIZEOF_STRUCT_MEM') with some data ('MIN_SIZE_ALIGNED').
+     * @todo we could leave out MIN_SIZE_ALIGNED. We would create an empty
+     *       region that couldn't hold data, but when mem->next gets freed,
+     *       the 2 regions would be combined, resulting in more free memory */
+    ptr2 = ptr + SIZEOF_STRUCT_MEM + newsize;
+    mem2 = (struct mem *)(void *)&ram[ptr2];
+    if (mem2 < lfree) {
+      lfree = mem2;
+    }
+    mem2->used = 0;
+    mem2->next = mem->next;
+    mem2->prev = ptr;
+    mem->next = ptr2;
+    if (mem2->next != MEM_SIZE_ALIGNED) {
+      ((struct mem *)(void *)&ram[mem2->next])->prev = ptr2;
+    }
+    MEM_STATS_DEC_USED(used, (size - newsize));
+    /* the original mem->next is used, so no need to plug holes! */
+  }
+  /* else {
+    next struct mem is used but size between mem and mem2 is not big enough
+    to create another struct mem
+    -> don't do anyhting. 
+    -> the remaining space stays unused since it is too small
+  } */
+#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT
+  mem_free_count = 1;
+#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */
+  LWIP_MEM_FREE_UNPROTECT();
+  return rmem;
+}
+
+/**
+ * Adam's mem_malloc() plus solution for bug #17922
+ * Allocate a block of memory with a minimum of 'size' bytes.
+ *
+ * @param size is the minimum size of the requested block in bytes.
+ * @return pointer to allocated memory or NULL if no free memory was found.
+ *
+ * Note that the returned value will always be aligned (as defined by MEM_ALIGNMENT).
+ */
+void *
+mem_malloc(mem_size_t size)
+{
+  mem_size_t ptr, ptr2;
+  struct mem *mem, *mem2;
+#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT
+  u8_t local_mem_free_count = 0;
+#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */
+  LWIP_MEM_ALLOC_DECL_PROTECT();
+
+  if (size == 0) {
+    return NULL;
+  }
+
+  /* Expand the size of the allocated memory region so that we can
+     adjust for alignment. */
+  size = LWIP_MEM_ALIGN_SIZE(size);
+
+  if(size < MIN_SIZE_ALIGNED) {
+    /* every data block must be at least MIN_SIZE_ALIGNED long */
+    size = MIN_SIZE_ALIGNED;
+  }
+
+  if (size > MEM_SIZE_ALIGNED) {
+    return NULL;
+  }
+
+  /* protect the heap from concurrent access */
+  sys_mutex_lock(&mem_mutex);
+  LWIP_MEM_ALLOC_PROTECT();
+#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT
+  /* run as long as a mem_free disturbed mem_malloc */
+  do {
+    local_mem_free_count = 0;
+#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */
+
+    /* Scan through the heap searching for a free block that is big enough,
+     * beginning with the lowest free block.
+     */
+    for (ptr = (mem_size_t)((u8_t *)lfree - ram); ptr < MEM_SIZE_ALIGNED - size;
+         ptr = ((struct mem *)(void *)&ram[ptr])->next) {
+      mem = (struct mem *)(void *)&ram[ptr];
+#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT
+      mem_free_count = 0;
+      LWIP_MEM_ALLOC_UNPROTECT();
+      /* allow mem_free to run */
+      LWIP_MEM_ALLOC_PROTECT();
+      if (mem_free_count != 0) {
+        local_mem_free_count = mem_free_count;
+      }
+      mem_free_count = 0;
+#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */
+
+      if ((!mem->used) &&
+          (mem->next - (ptr + SIZEOF_STRUCT_MEM)) >= size) {
+        /* mem is not used and at least perfect fit is possible:
+         * mem->next - (ptr + SIZEOF_STRUCT_MEM) gives us the 'user data size' of mem */
+
+        if (mem->next - (ptr + SIZEOF_STRUCT_MEM) >= (size + SIZEOF_STRUCT_MEM + MIN_SIZE_ALIGNED)) {
+          /* (in addition to the above, we test if another struct mem (SIZEOF_STRUCT_MEM) containing
+           * at least MIN_SIZE_ALIGNED of data also fits in the 'user data space' of 'mem')
+           * -> split large block, create empty remainder,
+           * remainder must be large enough to contain MIN_SIZE_ALIGNED data: if
+           * mem->next - (ptr + (2*SIZEOF_STRUCT_MEM)) == size,
+           * struct mem would fit in but no data between mem2 and mem2->next
+           * @todo we could leave out MIN_SIZE_ALIGNED. We would create an empty
+           *       region that couldn't hold data, but when mem->next gets freed,
+           *       the 2 regions would be combined, resulting in more free memory
+           */
+          ptr2 = ptr + SIZEOF_STRUCT_MEM + size;
+          /* create mem2 struct */
+          mem2 = (struct mem *)(void *)&ram[ptr2];
+          mem2->used = 0;
+          mem2->next = mem->next;
+          mem2->prev = ptr;
+          /* and insert it between mem and mem->next */
+          mem->next = ptr2;
+          mem->used = 1;
+
+          if (mem2->next != MEM_SIZE_ALIGNED) {
+            ((struct mem *)(void *)&ram[mem2->next])->prev = ptr2;
+          }
+          MEM_STATS_INC_USED(used, (size + SIZEOF_STRUCT_MEM));
+        } else {
+          /* (a mem2 struct does no fit into the user data space of mem and mem->next will always
+           * be used at this point: if not we have 2 unused structs in a row, plug_holes should have
+           * take care of this).
+           * -> near fit or excact fit: do not split, no mem2 creation
+           * also can't move mem->next directly behind mem, since mem->next
+           * will always be used at this point!
+           */
+          mem->used = 1;
+          MEM_STATS_INC_USED(used, mem->next - (mem_size_t)((u8_t *)mem - ram));
+        }
+
+        if (mem == lfree) {
+          /* Find next free block after mem and update lowest free pointer */
+          while (lfree->used && lfree != ram_end) {
+            LWIP_MEM_ALLOC_UNPROTECT();
+            /* prevent high interrupt latency... */
+            LWIP_MEM_ALLOC_PROTECT();
+            lfree = (struct mem *)(void *)&ram[lfree->next];
+          }
+          LWIP_ASSERT("mem_malloc: !lfree->used", ((lfree == ram_end) || (!lfree->used)));
+        }
+        LWIP_MEM_ALLOC_UNPROTECT();
+        sys_mutex_unlock(&mem_mutex);
+        LWIP_ASSERT("mem_malloc: allocated memory not above ram_end.",
+         (mem_ptr_t)mem + SIZEOF_STRUCT_MEM + size <= (mem_ptr_t)ram_end);
+        LWIP_ASSERT("mem_malloc: allocated memory properly aligned.",
+         ((mem_ptr_t)mem + SIZEOF_STRUCT_MEM) % MEM_ALIGNMENT == 0);
+        LWIP_ASSERT("mem_malloc: sanity check alignment",
+          (((mem_ptr_t)mem) & (MEM_ALIGNMENT-1)) == 0);
+
+        return (u8_t *)mem + SIZEOF_STRUCT_MEM;
+      }
+    }
+#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT
+    /* if we got interrupted by a mem_free, try again */
+  } while(local_mem_free_count != 0);
+#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */
+  LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("mem_malloc: could not allocate %"S16_F" bytes\n", (s16_t)size));
+  MEM_STATS_INC(err);
+  LWIP_MEM_ALLOC_UNPROTECT();
+  sys_mutex_unlock(&mem_mutex);
+  return NULL;
+}
+
+#endif /* MEM_USE_POOLS */
+/**
+ * Contiguously allocates enough space for count objects that are size bytes
+ * of memory each and returns a pointer to the allocated memory.
+ *
+ * The allocated memory is filled with bytes of value zero.
+ *
+ * @param count number of objects to allocate
+ * @param size size of the objects to allocate
+ * @return pointer to allocated memory / NULL pointer if there is an error
+ */
+void *mem_calloc(mem_size_t count, mem_size_t size)
+{
+  void *p;
+
+  /* allocate 'count' objects of size 'size' */
+  p = mem_malloc(count * size);
+  if (p) {
+    /* zero the memory */
+    memset(p, 0, count * size);
+  }
+  return p;
+}
+
+#endif /* !MEM_LIBC_MALLOC */
diff --git a/core/lwip/src/core/memp.c b/core/lwip/src/core/memp.c
new file mode 100644
index 00000000..4da879a5
--- /dev/null
+++ b/core/lwip/src/core/memp.c
@@ -0,0 +1,469 @@
+/**
+ * @file
+ * Dynamic pool memory manager
+ *
+ * lwIP has dedicated pools for many structures (netconn, protocol control blocks,
+ * packet buffers, ...). All these pools are managed here.
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#include "lwip/memp.h"
+#include "lwip/pbuf.h"
+#include "lwip/udp.h"
+#include "lwip/raw.h"
+#include "lwip/tcp_impl.h"
+#include "lwip/igmp.h"
+#include "lwip/api.h"
+#include "lwip/api_msg.h"
+#include "lwip/tcpip.h"
+#include "lwip/sys.h"
+#include "lwip/timers.h"
+#include "lwip/stats.h"
+#include "netif/etharp.h"
+#include "lwip/ip_frag.h"
+#include "lwip/snmp_structs.h"
+#include "lwip/snmp_msg.h"
+#include "lwip/dns.h"
+#include "netif/ppp_oe.h"
+
+#include <string.h>
+
+#if !MEMP_MEM_MALLOC /* don't build if not configured for use in lwipopts.h */
+
+struct memp {
+  struct memp *next;
+#if MEMP_OVERFLOW_CHECK
+  const char *file;
+  int line;
+#endif /* MEMP_OVERFLOW_CHECK */
+};
+
+#if MEMP_OVERFLOW_CHECK
+/* if MEMP_OVERFLOW_CHECK is turned on, we reserve some bytes at the beginning
+ * and at the end of each element, initialize them as 0xcd and check
+ * them later. */
+/* If MEMP_OVERFLOW_CHECK is >= 2, on every call to memp_malloc or memp_free,
+ * every single element in each pool is checked!
+ * This is VERY SLOW but also very helpful. */
+/* MEMP_SANITY_REGION_BEFORE and MEMP_SANITY_REGION_AFTER can be overridden in
+ * lwipopts.h to change the amount reserved for checking. */
+#ifndef MEMP_SANITY_REGION_BEFORE
+#define MEMP_SANITY_REGION_BEFORE  16
+#endif /* MEMP_SANITY_REGION_BEFORE*/
+#if MEMP_SANITY_REGION_BEFORE > 0
+#define MEMP_SANITY_REGION_BEFORE_ALIGNED    LWIP_MEM_ALIGN_SIZE(MEMP_SANITY_REGION_BEFORE)
+#else
+#define MEMP_SANITY_REGION_BEFORE_ALIGNED    0
+#endif /* MEMP_SANITY_REGION_BEFORE*/
+#ifndef MEMP_SANITY_REGION_AFTER
+#define MEMP_SANITY_REGION_AFTER   16
+#endif /* MEMP_SANITY_REGION_AFTER*/
+#if MEMP_SANITY_REGION_AFTER > 0
+#define MEMP_SANITY_REGION_AFTER_ALIGNED     LWIP_MEM_ALIGN_SIZE(MEMP_SANITY_REGION_AFTER)
+#else
+#define MEMP_SANITY_REGION_AFTER_ALIGNED     0
+#endif /* MEMP_SANITY_REGION_AFTER*/
+
+/* MEMP_SIZE: save space for struct memp and for sanity check */
+#define MEMP_SIZE          (LWIP_MEM_ALIGN_SIZE(sizeof(struct memp)) + MEMP_SANITY_REGION_BEFORE_ALIGNED)
+#define MEMP_ALIGN_SIZE(x) (LWIP_MEM_ALIGN_SIZE(x) + MEMP_SANITY_REGION_AFTER_ALIGNED)
+
+#else /* MEMP_OVERFLOW_CHECK */
+
+/* No sanity checks
+ * We don't need to preserve the struct memp while not allocated, so we
+ * can save a little space and set MEMP_SIZE to 0.
+ */
+#define MEMP_SIZE           0
+#define MEMP_ALIGN_SIZE(x) (LWIP_MEM_ALIGN_SIZE(x))
+
+#endif /* MEMP_OVERFLOW_CHECK */
+
+/** This array holds the first free element of each pool.
+ *  Elements form a linked list. */
+static struct memp *memp_tab[MEMP_MAX];
+
+#else /* MEMP_MEM_MALLOC */
+
+#define MEMP_ALIGN_SIZE(x) (LWIP_MEM_ALIGN_SIZE(x))
+
+#endif /* MEMP_MEM_MALLOC */
+
+/** This array holds the element sizes of each pool. */
+#if !MEM_USE_POOLS && !MEMP_MEM_MALLOC
+static
+#endif
+const u16_t memp_sizes[MEMP_MAX] = {
+#define LWIP_MEMPOOL(name,num,size,desc)  LWIP_MEM_ALIGN_SIZE(size),
+#include "lwip/memp_std.h"
+};
+
+#if !MEMP_MEM_MALLOC /* don't build if not configured for use in lwipopts.h */
+
+/** This array holds the number of elements in each pool. */
+static const u16_t memp_num[MEMP_MAX] = {
+#define LWIP_MEMPOOL(name,num,size,desc)  (num),
+#include "lwip/memp_std.h"
+};
+
+/** This array holds a textual description of each pool. */
+#ifdef LWIP_DEBUG
+static const char *memp_desc[MEMP_MAX] = {
+#define LWIP_MEMPOOL(name,num,size,desc)  (desc),
+#include "lwip/memp_std.h"
+};
+#endif /* LWIP_DEBUG */
+
+#if MEMP_SEPARATE_POOLS
+
+/** This creates each memory pool. These are named memp_memory_XXX_base (where
+ * XXX is the name of the pool defined in memp_std.h).
+ * To relocate a pool, declare it as extern in cc.h. Example for GCC:
+ *   extern u8_t __attribute__((section(".onchip_mem"))) memp_memory_UDP_PCB_base[];
+ */
+#define LWIP_MEMPOOL(name,num,size,desc) u8_t memp_memory_ ## name ## _base \
+  [((num) * (MEMP_SIZE + MEMP_ALIGN_SIZE(size)))];   
+#include "lwip/memp_std.h"
+
+/** This array holds the base of each memory pool. */
+static u8_t *const memp_bases[] = { 
+#define LWIP_MEMPOOL(name,num,size,desc) memp_memory_ ## name ## _base,   
+#include "lwip/memp_std.h"
+};
+
+#else /* MEMP_SEPARATE_POOLS */
+
+/** This is the actual memory used by the pools (all pools in one big block). */
+static u8_t memp_memory[MEM_ALIGNMENT - 1 
+#define LWIP_MEMPOOL(name,num,size,desc) + ( (num) * (MEMP_SIZE + MEMP_ALIGN_SIZE(size) ) )
+#include "lwip/memp_std.h"
+];
+
+#endif /* MEMP_SEPARATE_POOLS */
+
+#if MEMP_SANITY_CHECK
+/**
+ * Check that memp-lists don't form a circle
+ */
+static int
+memp_sanity(void)
+{
+  s16_t i, c;
+  struct memp *m, *n;
+
+  for (i = 0; i < MEMP_MAX; i++) {
+    for (m = memp_tab[i]; m != NULL; m = m->next) {
+      c = 1;
+      for (n = memp_tab[i]; n != NULL; n = n->next) {
+        if (n == m && --c < 0) {
+          return 0;
+        }
+      }
+    }
+  }
+  return 1;
+}
+#endif /* MEMP_SANITY_CHECK*/
+#if MEMP_OVERFLOW_CHECK
+#if defined(LWIP_DEBUG) && MEMP_STATS
+static const char * memp_overflow_names[] = {
+#define LWIP_MEMPOOL(name,num,size,desc) "/"desc,
+#include "lwip/memp_std.h"
+  };
+#endif
+
+/**
+ * Check if a memp element was victim of an overflow
+ * (e.g. the restricted area after it has been altered)
+ *
+ * @param p the memp element to check
+ * @param memp_type the pool p comes from
+ */
+static void
+memp_overflow_check_element_overflow(struct memp *p, u16_t memp_type)
+{
+  u16_t k;
+  u8_t *m;
+#if MEMP_SANITY_REGION_AFTER_ALIGNED > 0
+  m = (u8_t*)p + MEMP_SIZE + memp_sizes[memp_type];
+  for (k = 0; k < MEMP_SANITY_REGION_AFTER_ALIGNED; k++) {
+    if (m[k] != 0xcd) {
+      char errstr[128] = "detected memp overflow in pool ";
+      char digit[] = "0";
+      if(memp_type >= 10) {
+        digit[0] = '0' + (memp_type/10);
+        strcat(errstr, digit);
+      }
+      digit[0] = '0' + (memp_type%10);
+      strcat(errstr, digit);
+#if defined(LWIP_DEBUG) && MEMP_STATS
+      strcat(errstr, memp_overflow_names[memp_type]);
+#endif
+      LWIP_ASSERT(errstr, 0);
+    }
+  }
+#endif
+}
+
+/**
+ * Check if a memp element was victim of an underflow
+ * (e.g. the restricted area before it has been altered)
+ *
+ * @param p the memp element to check
+ * @param memp_type the pool p comes from
+ */
+static void
+memp_overflow_check_element_underflow(struct memp *p, u16_t memp_type)
+{
+  u16_t k;
+  u8_t *m;
+#if MEMP_SANITY_REGION_BEFORE_ALIGNED > 0
+  m = (u8_t*)p + MEMP_SIZE - MEMP_SANITY_REGION_BEFORE_ALIGNED;
+  for (k = 0; k < MEMP_SANITY_REGION_BEFORE_ALIGNED; k++) {
+    if (m[k] != 0xcd) {
+      char errstr[128] = "detected memp underflow in pool ";
+      char digit[] = "0";
+      if(memp_type >= 10) {
+        digit[0] = '0' + (memp_type/10);
+        strcat(errstr, digit);
+      }
+      digit[0] = '0' + (memp_type%10);
+      strcat(errstr, digit);
+#if defined(LWIP_DEBUG) && MEMP_STATS
+      strcat(errstr, memp_overflow_names[memp_type]);
+#endif
+      LWIP_ASSERT(errstr, 0);
+    }
+  }
+#endif
+}
+
+/**
+ * Do an overflow check for all elements in every pool.
+ *
+ * @see memp_overflow_check_element for a description of the check
+ */
+static void
+memp_overflow_check_all(void)
+{
+  u16_t i, j;
+  struct memp *p;
+
+  p = (struct memp *)LWIP_MEM_ALIGN(memp_memory);
+  for (i = 0; i < MEMP_MAX; ++i) {
+    p = p;
+    for (j = 0; j < memp_num[i]; ++j) {
+      memp_overflow_check_element_overflow(p, i);
+      p = (struct memp*)((u8_t*)p + MEMP_SIZE + memp_sizes[i] + MEMP_SANITY_REGION_AFTER_ALIGNED);
+    }
+  }
+  p = (struct memp *)LWIP_MEM_ALIGN(memp_memory);
+  for (i = 0; i < MEMP_MAX; ++i) {
+    p = p;
+    for (j = 0; j < memp_num[i]; ++j) {
+      memp_overflow_check_element_underflow(p, i);
+      p = (struct memp*)((u8_t*)p + MEMP_SIZE + memp_sizes[i] + MEMP_SANITY_REGION_AFTER_ALIGNED);
+    }
+  }
+}
+
+/**
+ * Initialize the restricted areas of all memp elements in every pool.
+ */
+static void
+memp_overflow_init(void)
+{
+  u16_t i, j;
+  struct memp *p;
+  u8_t *m;
+
+  p = (struct memp *)LWIP_MEM_ALIGN(memp_memory);
+  for (i = 0; i < MEMP_MAX; ++i) {
+    p = p;
+    for (j = 0; j < memp_num[i]; ++j) {
+#if MEMP_SANITY_REGION_BEFORE_ALIGNED > 0
+      m = (u8_t*)p + MEMP_SIZE - MEMP_SANITY_REGION_BEFORE_ALIGNED;
+      memset(m, 0xcd, MEMP_SANITY_REGION_BEFORE_ALIGNED);
+#endif
+#if MEMP_SANITY_REGION_AFTER_ALIGNED > 0
+      m = (u8_t*)p + MEMP_SIZE + memp_sizes[i];
+      memset(m, 0xcd, MEMP_SANITY_REGION_AFTER_ALIGNED);
+#endif
+      p = (struct memp*)((u8_t*)p + MEMP_SIZE + memp_sizes[i] + MEMP_SANITY_REGION_AFTER_ALIGNED);
+    }
+  }
+}
+#endif /* MEMP_OVERFLOW_CHECK */
+
+/**
+ * Initialize this module.
+ * 
+ * Carves out memp_memory into linked lists for each pool-type.
+ */
+void
+memp_init(void)
+{
+  struct memp *memp;
+  u16_t i, j;
+
+  for (i = 0; i < MEMP_MAX; ++i) {
+    MEMP_STATS_AVAIL(used, i, 0);
+    MEMP_STATS_AVAIL(max, i, 0);
+    MEMP_STATS_AVAIL(err, i, 0);
+    MEMP_STATS_AVAIL(avail, i, memp_num[i]);
+  }
+
+#if !MEMP_SEPARATE_POOLS
+  memp = (struct memp *)LWIP_MEM_ALIGN(memp_memory);
+#endif /* !MEMP_SEPARATE_POOLS */
+  /* for every pool: */
+  for (i = 0; i < MEMP_MAX; ++i) {
+    memp_tab[i] = NULL;
+#if MEMP_SEPARATE_POOLS
+    memp = (struct memp*)memp_bases[i];
+#endif /* MEMP_SEPARATE_POOLS */
+    /* create a linked list of memp elements */
+    for (j = 0; j < memp_num[i]; ++j) {
+      memp->next = memp_tab[i];
+      memp_tab[i] = memp;
+      memp = (struct memp *)(void *)((u8_t *)memp + MEMP_SIZE + memp_sizes[i]
+#if MEMP_OVERFLOW_CHECK
+        + MEMP_SANITY_REGION_AFTER_ALIGNED
+#endif
+      );
+    }
+  }
+#if MEMP_OVERFLOW_CHECK
+  memp_overflow_init();
+  /* check everything a first time to see if it worked */
+  memp_overflow_check_all();
+#endif /* MEMP_OVERFLOW_CHECK */
+}
+
+/**
+ * Get an element from a specific pool.
+ *
+ * @param type the pool to get an element from
+ *
+ * the debug version has two more parameters:
+ * @param file file name calling this function
+ * @param line number of line where this function is called
+ *
+ * @return a pointer to the allocated memory or a NULL pointer on error
+ */
+void *
+#if !MEMP_OVERFLOW_CHECK
+memp_malloc(memp_t type)
+#else
+memp_malloc_fn(memp_t type, const char* file, const int line)
+#endif
+{
+  struct memp *memp;
+  SYS_ARCH_DECL_PROTECT(old_level);
+ 
+  LWIP_ERROR("memp_malloc: type < MEMP_MAX", (type < MEMP_MAX), return NULL;);
+
+  SYS_ARCH_PROTECT(old_level);
+#if MEMP_OVERFLOW_CHECK >= 2
+  memp_overflow_check_all();
+#endif /* MEMP_OVERFLOW_CHECK >= 2 */
+
+  memp = memp_tab[type];
+  
+  if (memp != NULL) {
+    memp_tab[type] = memp->next;
+#if MEMP_OVERFLOW_CHECK
+    memp->next = NULL;
+    memp->file = file;
+    memp->line = line;
+#endif /* MEMP_OVERFLOW_CHECK */
+    MEMP_STATS_INC_USED(used, type);
+    LWIP_ASSERT("memp_malloc: memp properly aligned",
+                ((mem_ptr_t)memp % MEM_ALIGNMENT) == 0);
+    memp = (struct memp*)(void *)((u8_t*)memp + MEMP_SIZE);
+  } else {
+    LWIP_DEBUGF(MEMP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("memp_malloc: out of memory in pool %s\n", memp_desc[type]));
+    MEMP_STATS_INC(err, type);
+  }
+
+  SYS_ARCH_UNPROTECT(old_level);
+
+  return memp;
+}
+
+/**
+ * Put an element back into its pool.
+ *
+ * @param type the pool where to put mem
+ * @param mem the memp element to free
+ */
+void
+memp_free(memp_t type, void *mem)
+{
+  struct memp *memp;
+  SYS_ARCH_DECL_PROTECT(old_level);
+
+  if (mem == NULL) {
+    return;
+  }
+  LWIP_ASSERT("memp_free: mem properly aligned",
+                ((mem_ptr_t)mem % MEM_ALIGNMENT) == 0);
+
+  memp = (struct memp *)(void *)((u8_t*)mem - MEMP_SIZE);
+
+  SYS_ARCH_PROTECT(old_level);
+#if MEMP_OVERFLOW_CHECK
+#if MEMP_OVERFLOW_CHECK >= 2
+  memp_overflow_check_all();
+#else
+  memp_overflow_check_element_overflow(memp, type);
+  memp_overflow_check_element_underflow(memp, type);
+#endif /* MEMP_OVERFLOW_CHECK >= 2 */
+#endif /* MEMP_OVERFLOW_CHECK */
+
+  MEMP_STATS_DEC(used, type); 
+  
+  memp->next = memp_tab[type]; 
+  memp_tab[type] = memp;
+
+#if MEMP_SANITY_CHECK
+  LWIP_ASSERT("memp sanity", memp_sanity());
+#endif /* MEMP_SANITY_CHECK */
+
+  SYS_ARCH_UNPROTECT(old_level);
+}
+
+#endif /* MEMP_MEM_MALLOC */
diff --git a/core/lwip/src/core/netif.c b/core/lwip/src/core/netif.c
new file mode 100644
index 00000000..f190b1f2
--- /dev/null
+++ b/core/lwip/src/core/netif.c
@@ -0,0 +1,752 @@
+/**
+ * @file
+ * lwIP network interface abstraction
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#include "lwip/def.h"
+#include "lwip/ip_addr.h"
+#include "lwip/netif.h"
+#include "lwip/tcp_impl.h"
+#include "lwip/snmp.h"
+#include "lwip/igmp.h"
+#include "netif/etharp.h"
+#include "lwip/stats.h"
+#if ENABLE_LOOPBACK
+#include "lwip/sys.h"
+#if LWIP_NETIF_LOOPBACK_MULTITHREADING
+#include "lwip/tcpip.h"
+#endif /* LWIP_NETIF_LOOPBACK_MULTITHREADING */
+#endif /* ENABLE_LOOPBACK */
+
+#if LWIP_AUTOIP
+#include "lwip/autoip.h"
+#endif /* LWIP_AUTOIP */
+#if LWIP_DHCP
+#include "lwip/dhcp.h"
+#endif /* LWIP_DHCP */
+
+#if LWIP_NETIF_STATUS_CALLBACK
+#define NETIF_STATUS_CALLBACK(n) do{ if (n->status_callback) { (n->status_callback)(n); }}while(0)
+#else
+#define NETIF_STATUS_CALLBACK(n)
+#endif /* LWIP_NETIF_STATUS_CALLBACK */ 
+
+#if LWIP_NETIF_LINK_CALLBACK
+#define NETIF_LINK_CALLBACK(n) do{ if (n->link_callback) { (n->link_callback)(n); }}while(0)
+#else
+#define NETIF_LINK_CALLBACK(n)
+#endif /* LWIP_NETIF_LINK_CALLBACK */ 
+
+struct netif *netif_list;
+struct netif *netif_default;
+
+#if LWIP_HAVE_LOOPIF
+static struct netif loop_netif;
+
+/**
+ * Initialize a lwip network interface structure for a loopback interface
+ *
+ * @param netif the lwip network interface structure for this loopif
+ * @return ERR_OK if the loopif is initialized
+ *         ERR_MEM if private data couldn't be allocated
+ */
+static err_t
+netif_loopif_init(struct netif *netif)
+{
+  /* initialize the snmp variables and counters inside the struct netif
+   * ifSpeed: no assumption can be made!
+   */
+  NETIF_INIT_SNMP(netif, snmp_ifType_softwareLoopback, 0);
+
+  netif->name[0] = 'l';
+  netif->name[1] = 'o';
+  netif->output = netif_loop_output;
+  return ERR_OK;
+}
+#endif /* LWIP_HAVE_LOOPIF */
+
+void
+netif_init(void)
+{
+#if LWIP_HAVE_LOOPIF
+  ip_addr_t loop_ipaddr, loop_netmask, loop_gw;
+  IP4_ADDR(&loop_gw, 127,0,0,1);
+  IP4_ADDR(&loop_ipaddr, 127,0,0,1);
+  IP4_ADDR(&loop_netmask, 255,0,0,0);
+
+#if NO_SYS
+  netif_add(&loop_netif, &loop_ipaddr, &loop_netmask, &loop_gw, NULL, netif_loopif_init, ip_input);
+#else  /* NO_SYS */
+  netif_add(&loop_netif, &loop_ipaddr, &loop_netmask, &loop_gw, NULL, netif_loopif_init, tcpip_input);
+#endif /* NO_SYS */
+  netif_set_up(&loop_netif);
+
+#endif /* LWIP_HAVE_LOOPIF */
+}
+
+/**
+ * Add a network interface to the list of lwIP netifs.
+ *
+ * @param netif a pre-allocated netif structure
+ * @param ipaddr IP address for the new netif
+ * @param netmask network mask for the new netif
+ * @param gw default gateway IP address for the new netif
+ * @param state opaque data passed to the new netif
+ * @param init callback function that initializes the interface
+ * @param input callback function that is called to pass
+ * ingress packets up in the protocol layer stack.
+ *
+ * @return netif, or NULL if failed.
+ */
+struct netif *
+netif_add(struct netif *netif, ip_addr_t *ipaddr, ip_addr_t *netmask,
+  ip_addr_t *gw, void *state, netif_init_fn init, netif_input_fn input)
+{
+  static u8_t netifnum = 0;
+
+  LWIP_ASSERT("No init function given", init != NULL);
+
+  /* reset new interface configuration state */
+  ip_addr_set_zero(&netif->ip_addr);
+  ip_addr_set_zero(&netif->netmask);
+  ip_addr_set_zero(&netif->gw);
+  netif->flags = 0;
+#if LWIP_DHCP
+  /* netif not under DHCP control by default */
+  netif->dhcp = NULL;
+#endif /* LWIP_DHCP */
+#if LWIP_AUTOIP
+  /* netif not under AutoIP control by default */
+  netif->autoip = NULL;
+#endif /* LWIP_AUTOIP */
+#if LWIP_NETIF_STATUS_CALLBACK
+  netif->status_callback = NULL;
+#endif /* LWIP_NETIF_STATUS_CALLBACK */
+#if LWIP_NETIF_LINK_CALLBACK
+  netif->link_callback = NULL;
+#endif /* LWIP_NETIF_LINK_CALLBACK */
+#if LWIP_IGMP
+  netif->igmp_mac_filter = NULL;
+#endif /* LWIP_IGMP */
+#if ENABLE_LOOPBACK
+  netif->loop_first = NULL;
+  netif->loop_last = NULL;
+#endif /* ENABLE_LOOPBACK */
+
+  /* remember netif specific state information data */
+  netif->state = state;
+  netif->num = netifnum++;
+  netif->input = input;
+#if LWIP_NETIF_HWADDRHINT
+  netif->addr_hint = NULL;
+#endif /* LWIP_NETIF_HWADDRHINT*/
+#if ENABLE_LOOPBACK && LWIP_LOOPBACK_MAX_PBUFS
+  netif->loop_cnt_current = 0;
+#endif /* ENABLE_LOOPBACK && LWIP_LOOPBACK_MAX_PBUFS */
+
+  netif_set_addr(netif, ipaddr, netmask, gw);
+
+  /* call user specified initialization function for netif */
+  if (init(netif) != ERR_OK) {
+    return NULL;
+  }
+
+  /* add this netif to the list */
+  netif->next = netif_list;
+  netif_list = netif;
+  snmp_inc_iflist();
+
+#if LWIP_IGMP
+  /* start IGMP processing */
+  if (netif->flags & NETIF_FLAG_IGMP) {
+    igmp_start(netif);
+  }
+#endif /* LWIP_IGMP */
+
+  LWIP_DEBUGF(NETIF_DEBUG, ("netif: added interface %c%c IP addr ",
+    netif->name[0], netif->name[1]));
+  ip_addr_debug_print(NETIF_DEBUG, ipaddr);
+  LWIP_DEBUGF(NETIF_DEBUG, (" netmask "));
+  ip_addr_debug_print(NETIF_DEBUG, netmask);
+  LWIP_DEBUGF(NETIF_DEBUG, (" gw "));
+  ip_addr_debug_print(NETIF_DEBUG, gw);
+  LWIP_DEBUGF(NETIF_DEBUG, ("\n"));
+  return netif;
+}
+
+/**
+ * Change IP address configuration for a network interface (including netmask
+ * and default gateway).
+ *
+ * @param netif the network interface to change
+ * @param ipaddr the new IP address
+ * @param netmask the new netmask
+ * @param gw the new default gateway
+ */
+void
+netif_set_addr(struct netif *netif, ip_addr_t *ipaddr, ip_addr_t *netmask,
+    ip_addr_t *gw)
+{
+  netif_set_ipaddr(netif, ipaddr);
+  netif_set_netmask(netif, netmask);
+  netif_set_gw(netif, gw);
+}
+
+/**
+ * Remove a network interface from the list of lwIP netifs.
+ *
+ * @param netif the network interface to remove
+ */
+void
+netif_remove(struct netif *netif)
+{
+  if (netif == NULL) {
+    return;
+  }
+
+#if LWIP_IGMP
+  /* stop IGMP processing */
+  if (netif->flags & NETIF_FLAG_IGMP) {
+    igmp_stop(netif);
+  }
+#endif /* LWIP_IGMP */
+  if (netif_is_up(netif)) {
+    /* set netif down before removing (call callback function) */
+    netif_set_down(netif);
+  }
+
+  snmp_delete_ipaddridx_tree(netif);
+
+  /*  is it the first netif? */
+  if (netif_list == netif) {
+    netif_list = netif->next;
+  } else {
+    /*  look for netif further down the list */
+    struct netif * tmpNetif;
+    for (tmpNetif = netif_list; tmpNetif != NULL; tmpNetif = tmpNetif->next) {
+      if (tmpNetif->next == netif) {
+        tmpNetif->next = netif->next;
+        break;
+      }
+    }
+    if (tmpNetif == NULL)
+      return; /*  we didn't find any netif today */
+  }
+  snmp_dec_iflist();
+  /* this netif is default? */
+  if (netif_default == netif) {
+    /* reset default netif */
+    netif_set_default(NULL);
+  }
+  LWIP_DEBUGF( NETIF_DEBUG, ("netif_remove: removed netif\n") );
+}
+
+/**
+ * Find a network interface by searching for its name
+ *
+ * @param name the name of the netif (like netif->name) plus concatenated number
+ * in ascii representation (e.g. 'en0')
+ */
+struct netif *
+netif_find(char *name)
+{
+  struct netif *netif;
+  u8_t num;
+
+  if (name == NULL) {
+    return NULL;
+  }
+
+  num = name[2] - '0';
+
+  for(netif = netif_list; netif != NULL; netif = netif->next) {
+    if (num == netif->num &&
+       name[0] == netif->name[0] &&
+       name[1] == netif->name[1]) {
+      LWIP_DEBUGF(NETIF_DEBUG, ("netif_find: found %c%c\n", name[0], name[1]));
+      return netif;
+    }
+  }
+  LWIP_DEBUGF(NETIF_DEBUG, ("netif_find: didn't find %c%c\n", name[0], name[1]));
+  return NULL;
+}
+
+/**
+ * Change the IP address of a network interface
+ *
+ * @param netif the network interface to change
+ * @param ipaddr the new IP address
+ *
+ * @note call netif_set_addr() if you also want to change netmask and
+ * default gateway
+ */
+void
+netif_set_ipaddr(struct netif *netif, ip_addr_t *ipaddr)
+{
+  /* TODO: Handling of obsolete pcbs */
+  /* See:  http://mail.gnu.org/archive/html/lwip-users/2003-03/msg00118.html */
+#if LWIP_TCP
+  struct tcp_pcb *pcb;
+  struct tcp_pcb_listen *lpcb;
+
+  /* address is actually being changed? */
+  if ((ip_addr_cmp(ipaddr, &(netif->ip_addr))) == 0) {
+    /* extern struct tcp_pcb *tcp_active_pcbs; defined by tcp.h */
+    LWIP_DEBUGF(NETIF_DEBUG | LWIP_DBG_STATE, ("netif_set_ipaddr: netif address being changed\n"));
+    pcb = tcp_active_pcbs;
+    while (pcb != NULL) {
+      /* PCB bound to current local interface address? */
+      if (ip_addr_cmp(&(pcb->local_ip), &(netif->ip_addr))
+#if LWIP_AUTOIP
+        /* connections to link-local addresses must persist (RFC3927 ch. 1.9) */
+        && !ip_addr_islinklocal(&(pcb->local_ip))
+#endif /* LWIP_AUTOIP */
+        ) {
+        /* this connection must be aborted */
+        struct tcp_pcb *next = pcb->next;
+        LWIP_DEBUGF(NETIF_DEBUG | LWIP_DBG_STATE, ("netif_set_ipaddr: aborting TCP pcb %p\n", (void *)pcb));
+        tcp_abort(pcb);
+        pcb = next;
+      } else {
+        pcb = pcb->next;
+      }
+    }
+    for (lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
+      /* PCB bound to current local interface address? */
+      if ((!(ip_addr_isany(&(lpcb->local_ip)))) &&
+          (ip_addr_cmp(&(lpcb->local_ip), &(netif->ip_addr)))) {
+        /* The PCB is listening to the old ipaddr and
+         * is set to listen to the new one instead */
+        ip_addr_set(&(lpcb->local_ip), ipaddr);
+      }
+    }
+  }
+#endif
+  snmp_delete_ipaddridx_tree(netif);
+  snmp_delete_iprteidx_tree(0,netif);
+  /* set new IP address to netif */
+  ip_addr_set(&(netif->ip_addr), ipaddr);
+  snmp_insert_ipaddridx_tree(netif);
+  snmp_insert_iprteidx_tree(0,netif);
+
+  LWIP_DEBUGF(NETIF_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("netif: IP address of interface %c%c set to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+    netif->name[0], netif->name[1],
+    ip4_addr1_16(&netif->ip_addr),
+    ip4_addr2_16(&netif->ip_addr),
+    ip4_addr3_16(&netif->ip_addr),
+    ip4_addr4_16(&netif->ip_addr)));
+}
+
+/**
+ * Change the default gateway for a network interface
+ *
+ * @param netif the network interface to change
+ * @param gw the new default gateway
+ *
+ * @note call netif_set_addr() if you also want to change ip address and netmask
+ */
+void
+netif_set_gw(struct netif *netif, ip_addr_t *gw)
+{
+  ip_addr_set(&(netif->gw), gw);
+  LWIP_DEBUGF(NETIF_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("netif: GW address of interface %c%c set to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+    netif->name[0], netif->name[1],
+    ip4_addr1_16(&netif->gw),
+    ip4_addr2_16(&netif->gw),
+    ip4_addr3_16(&netif->gw),
+    ip4_addr4_16(&netif->gw)));
+}
+
+/**
+ * Change the netmask of a network interface
+ *
+ * @param netif the network interface to change
+ * @param netmask the new netmask
+ *
+ * @note call netif_set_addr() if you also want to change ip address and
+ * default gateway
+ */
+void
+netif_set_netmask(struct netif *netif, ip_addr_t *netmask)
+{
+  snmp_delete_iprteidx_tree(0, netif);
+  /* set new netmask to netif */
+  ip_addr_set(&(netif->netmask), netmask);
+  snmp_insert_iprteidx_tree(0, netif);
+  LWIP_DEBUGF(NETIF_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("netif: netmask of interface %c%c set to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+    netif->name[0], netif->name[1],
+    ip4_addr1_16(&netif->netmask),
+    ip4_addr2_16(&netif->netmask),
+    ip4_addr3_16(&netif->netmask),
+    ip4_addr4_16(&netif->netmask)));
+}
+
+/**
+ * Set a network interface as the default network interface
+ * (used to output all packets for which no specific route is found)
+ *
+ * @param netif the default network interface
+ */
+void
+netif_set_default(struct netif *netif)
+{
+  if (netif == NULL) {
+    /* remove default route */
+    snmp_delete_iprteidx_tree(1, netif);
+  } else {
+    /* install default route */
+    snmp_insert_iprteidx_tree(1, netif);
+  }
+  netif_default = netif;
+  LWIP_DEBUGF(NETIF_DEBUG, ("netif: setting default interface %c%c\n",
+           netif ? netif->name[0] : '\'', netif ? netif->name[1] : '\''));
+}
+
+/**
+ * Bring an interface up, available for processing
+ * traffic.
+ * 
+ * @note: Enabling DHCP on a down interface will make it come
+ * up once configured.
+ * 
+ * @see dhcp_start()
+ */ 
+void netif_set_up(struct netif *netif)
+{
+  if (!(netif->flags & NETIF_FLAG_UP)) {
+    netif->flags |= NETIF_FLAG_UP;
+    
+#if LWIP_SNMP
+    snmp_get_sysuptime(&netif->ts);
+#endif /* LWIP_SNMP */
+
+    NETIF_STATUS_CALLBACK(netif);
+
+    if (netif->flags & NETIF_FLAG_LINK_UP) {
+#if LWIP_ARP
+      /* For Ethernet network interfaces, we would like to send a "gratuitous ARP" */ 
+      if (netif->flags & (NETIF_FLAG_ETHARP)) {
+        etharp_gratuitous(netif);
+      }
+#endif /* LWIP_ARP */
+
+#if LWIP_IGMP
+      /* resend IGMP memberships */
+      if (netif->flags & NETIF_FLAG_IGMP) {
+        igmp_report_groups( netif);
+      }
+#endif /* LWIP_IGMP */
+    }
+  }
+}
+
+/**
+ * Bring an interface down, disabling any traffic processing.
+ *
+ * @note: Enabling DHCP on a down interface will make it come
+ * up once configured.
+ * 
+ * @see dhcp_start()
+ */ 
+void netif_set_down(struct netif *netif)
+{
+  if (netif->flags & NETIF_FLAG_UP) {
+    netif->flags &= ~NETIF_FLAG_UP;
+#if LWIP_SNMP
+    snmp_get_sysuptime(&netif->ts);
+#endif
+
+    NETIF_STATUS_CALLBACK(netif);
+  }
+}
+
+#if LWIP_NETIF_STATUS_CALLBACK
+/**
+ * Set callback to be called when interface is brought up/down
+ */
+void netif_set_status_callback(struct netif *netif, netif_status_callback_fn status_callback)
+{
+  if (netif) {
+    netif->status_callback = status_callback;
+  }
+}
+#endif /* LWIP_NETIF_STATUS_CALLBACK */
+
+/**
+ * Called by a driver when its link goes up
+ */
+void netif_set_link_up(struct netif *netif )
+{
+  if (!(netif->flags & NETIF_FLAG_LINK_UP)) {
+    netif->flags |= NETIF_FLAG_LINK_UP;
+
+#if LWIP_DHCP
+    if (netif->dhcp) {
+      dhcp_network_changed(netif);
+    }
+#endif /* LWIP_DHCP */
+
+#if LWIP_AUTOIP
+    if (netif->autoip) {
+      autoip_network_changed(netif);
+    }
+#endif /* LWIP_AUTOIP */
+
+    if (netif->flags & NETIF_FLAG_UP) {
+#if LWIP_ARP
+      /* For Ethernet network interfaces, we would like to send a "gratuitous ARP" */ 
+      if (netif->flags & NETIF_FLAG_ETHARP) {
+        etharp_gratuitous(netif);
+      }
+#endif /* LWIP_ARP */
+
+#if LWIP_IGMP
+      /* resend IGMP memberships */
+      if (netif->flags & NETIF_FLAG_IGMP) {
+        igmp_report_groups( netif);
+      }
+#endif /* LWIP_IGMP */
+    }
+    NETIF_LINK_CALLBACK(netif);
+  }
+}
+
+/**
+ * Called by a driver when its link goes down
+ */
+void netif_set_link_down(struct netif *netif )
+{
+  if (netif->flags & NETIF_FLAG_LINK_UP) {
+    netif->flags &= ~NETIF_FLAG_LINK_UP;
+    NETIF_LINK_CALLBACK(netif);
+  }
+}
+
+#if LWIP_NETIF_LINK_CALLBACK
+/**
+ * Set callback to be called when link is brought up/down
+ */
+void netif_set_link_callback(struct netif *netif, netif_status_callback_fn link_callback)
+{
+  if (netif) {
+    netif->link_callback = link_callback;
+  }
+}
+#endif /* LWIP_NETIF_LINK_CALLBACK */
+
+#if ENABLE_LOOPBACK
+/**
+ * Send an IP packet to be received on the same netif (loopif-like).
+ * The pbuf is simply copied and handed back to netif->input.
+ * In multithreaded mode, this is done directly since netif->input must put
+ * the packet on a queue.
+ * In callback mode, the packet is put on an internal queue and is fed to
+ * netif->input by netif_poll().
+ *
+ * @param netif the lwip network interface structure
+ * @param p the (IP) packet to 'send'
+ * @param ipaddr the ip address to send the packet to (not used)
+ * @return ERR_OK if the packet has been sent
+ *         ERR_MEM if the pbuf used to copy the packet couldn't be allocated
+ */
+err_t
+netif_loop_output(struct netif *netif, struct pbuf *p,
+       ip_addr_t *ipaddr)
+{
+  struct pbuf *r;
+  err_t err;
+  struct pbuf *last;
+#if LWIP_LOOPBACK_MAX_PBUFS
+  u8_t clen = 0;
+#endif /* LWIP_LOOPBACK_MAX_PBUFS */
+  /* If we have a loopif, SNMP counters are adjusted for it,
+   * if not they are adjusted for 'netif'. */
+#if LWIP_SNMP
+#if LWIP_HAVE_LOOPIF
+  struct netif *stats_if = &loop_netif;
+#else /* LWIP_HAVE_LOOPIF */
+  struct netif *stats_if = netif;
+#endif /* LWIP_HAVE_LOOPIF */
+#endif /* LWIP_SNMP */
+  SYS_ARCH_DECL_PROTECT(lev);
+  LWIP_UNUSED_ARG(ipaddr);
+
+  /* Allocate a new pbuf */
+  r = pbuf_alloc(PBUF_LINK, p->tot_len, PBUF_RAM);
+  if (r == NULL) {
+    LINK_STATS_INC(link.memerr);
+    LINK_STATS_INC(link.drop);
+    snmp_inc_ifoutdiscards(stats_if);
+    return ERR_MEM;
+  }
+#if LWIP_LOOPBACK_MAX_PBUFS
+  clen = pbuf_clen(r);
+  /* check for overflow or too many pbuf on queue */
+  if(((netif->loop_cnt_current + clen) < netif->loop_cnt_current) ||
+     ((netif->loop_cnt_current + clen) > LWIP_LOOPBACK_MAX_PBUFS)) {
+    pbuf_free(r);
+    LINK_STATS_INC(link.memerr);
+    LINK_STATS_INC(link.drop);
+    snmp_inc_ifoutdiscards(stats_if);
+    return ERR_MEM;
+  }
+  netif->loop_cnt_current += clen;
+#endif /* LWIP_LOOPBACK_MAX_PBUFS */
+
+  /* Copy the whole pbuf queue p into the single pbuf r */
+  if ((err = pbuf_copy(r, p)) != ERR_OK) {
+    pbuf_free(r);
+    LINK_STATS_INC(link.memerr);
+    LINK_STATS_INC(link.drop);
+    snmp_inc_ifoutdiscards(stats_if);
+    return err;
+  }
+
+  /* Put the packet on a linked list which gets emptied through calling
+     netif_poll(). */
+
+  /* let last point to the last pbuf in chain r */
+  for (last = r; last->next != NULL; last = last->next);
+
+  SYS_ARCH_PROTECT(lev);
+  if(netif->loop_first != NULL) {
+    LWIP_ASSERT("if first != NULL, last must also be != NULL", netif->loop_last != NULL);
+    netif->loop_last->next = r;
+    netif->loop_last = last;
+  } else {
+    netif->loop_first = r;
+    netif->loop_last = last;
+  }
+  SYS_ARCH_UNPROTECT(lev);
+
+  LINK_STATS_INC(link.xmit);
+  snmp_add_ifoutoctets(stats_if, p->tot_len);
+  snmp_inc_ifoutucastpkts(stats_if);
+
+#if LWIP_NETIF_LOOPBACK_MULTITHREADING
+  /* For multithreading environment, schedule a call to netif_poll */
+  tcpip_callback((tcpip_callback_fn)netif_poll, netif);
+#endif /* LWIP_NETIF_LOOPBACK_MULTITHREADING */
+
+  return ERR_OK;
+}
+
+/**
+ * Call netif_poll() in the main loop of your application. This is to prevent
+ * reentering non-reentrant functions like tcp_input(). Packets passed to
+ * netif_loop_output() are put on a list that is passed to netif->input() by
+ * netif_poll().
+ */
+void
+netif_poll(struct netif *netif)
+{
+  struct pbuf *in;
+  /* If we have a loopif, SNMP counters are adjusted for it,
+   * if not they are adjusted for 'netif'. */
+#if LWIP_SNMP
+#if LWIP_HAVE_LOOPIF
+  struct netif *stats_if = &loop_netif;
+#else /* LWIP_HAVE_LOOPIF */
+  struct netif *stats_if = netif;
+#endif /* LWIP_HAVE_LOOPIF */
+#endif /* LWIP_SNMP */
+  SYS_ARCH_DECL_PROTECT(lev);
+
+  do {
+    /* Get a packet from the list. With SYS_LIGHTWEIGHT_PROT=1, this is protected */
+    SYS_ARCH_PROTECT(lev);
+    in = netif->loop_first;
+    if (in != NULL) {
+      struct pbuf *in_end = in;
+#if LWIP_LOOPBACK_MAX_PBUFS
+      u8_t clen = pbuf_clen(in);
+      /* adjust the number of pbufs on queue */
+      LWIP_ASSERT("netif->loop_cnt_current underflow",
+        ((netif->loop_cnt_current - clen) < netif->loop_cnt_current));
+      netif->loop_cnt_current -= clen;
+#endif /* LWIP_LOOPBACK_MAX_PBUFS */
+      while (in_end->len != in_end->tot_len) {
+        LWIP_ASSERT("bogus pbuf: len != tot_len but next == NULL!", in_end->next != NULL);
+        in_end = in_end->next;
+      }
+      /* 'in_end' now points to the last pbuf from 'in' */
+      if (in_end == netif->loop_last) {
+        /* this was the last pbuf in the list */
+        netif->loop_first = netif->loop_last = NULL;
+      } else {
+        /* pop the pbuf off the list */
+        netif->loop_first = in_end->next;
+        LWIP_ASSERT("should not be null since first != last!", netif->loop_first != NULL);
+      }
+      /* De-queue the pbuf from its successors on the 'loop_' list. */
+      in_end->next = NULL;
+    }
+    SYS_ARCH_UNPROTECT(lev);
+
+    if (in != NULL) {
+      LINK_STATS_INC(link.recv);
+      snmp_add_ifinoctets(stats_if, in->tot_len);
+      snmp_inc_ifinucastpkts(stats_if);
+      /* loopback packets are always IP packets! */
+      if (ip_input(in, netif) != ERR_OK) {
+        pbuf_free(in);
+      }
+      /* Don't reference the packet any more! */
+      in = NULL;
+    }
+  /* go on while there is a packet on the list */
+  } while (netif->loop_first != NULL);
+}
+
+#if !LWIP_NETIF_LOOPBACK_MULTITHREADING
+/**
+ * Calls netif_poll() for every netif on the netif_list.
+ */
+void
+netif_poll_all(void)
+{
+  struct netif *netif = netif_list;
+  /* loop through netifs */
+  while (netif != NULL) {
+    netif_poll(netif);
+    /* proceed to next network interface */
+    netif = netif->next;
+  }
+}
+#endif /* !LWIP_NETIF_LOOPBACK_MULTITHREADING */
+#endif /* ENABLE_LOOPBACK */
diff --git a/core/lwip/src/core/pbuf.c b/core/lwip/src/core/pbuf.c
new file mode 100644
index 00000000..dd9ff64e
--- /dev/null
+++ b/core/lwip/src/core/pbuf.c
@@ -0,0 +1,1156 @@
+/**
+ * @file
+ * Packet buffer management
+ *
+ * Packets are built from the pbuf data structure. It supports dynamic
+ * memory allocation for packet contents or can reference externally
+ * managed packet contents both in RAM and ROM. Quick allocation for
+ * incoming packets is provided through pools with fixed sized pbufs.
+ *
+ * A packet may span over multiple pbufs, chained as a singly linked
+ * list. This is called a "pbuf chain".
+ *
+ * Multiple packets may be queued, also using this singly linked list.
+ * This is called a "packet queue".
+ * 
+ * So, a packet queue consists of one or more pbuf chains, each of
+ * which consist of one or more pbufs. CURRENTLY, PACKET QUEUES ARE
+ * NOT SUPPORTED!!! Use helper structs to queue multiple packets.
+ * 
+ * The differences between a pbuf chain and a packet queue are very
+ * precise but subtle. 
+ *
+ * The last pbuf of a packet has a ->tot_len field that equals the
+ * ->len field. It can be found by traversing the list. If the last
+ * pbuf of a packet has a ->next field other than NULL, more packets
+ * are on the queue.
+ *
+ * Therefore, looping through a pbuf of a single packet, has an
+ * loop end condition (tot_len == p->len), NOT (next == NULL).
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#include "lwip/stats.h"
+#include "lwip/def.h"
+#include "lwip/mem.h"
+#include "lwip/memp.h"
+#include "lwip/pbuf.h"
+#include "lwip/sys.h"
+#include "arch/perf.h"
+#if TCP_QUEUE_OOSEQ
+#include "lwip/tcp_impl.h"
+#endif
+#if LWIP_CHECKSUM_ON_COPY
+#include "lwip/inet_chksum.h"
+#endif
+
+#include <string.h>
+
+#define SIZEOF_STRUCT_PBUF        LWIP_MEM_ALIGN_SIZE(sizeof(struct pbuf))
+/* Since the pool is created in memp, PBUF_POOL_BUFSIZE will be automatically
+   aligned there. Therefore, PBUF_POOL_BUFSIZE_ALIGNED can be used here. */
+#define PBUF_POOL_BUFSIZE_ALIGNED LWIP_MEM_ALIGN_SIZE(PBUF_POOL_BUFSIZE)
+
+#if !LWIP_TCP || !TCP_QUEUE_OOSEQ || NO_SYS
+#define PBUF_POOL_IS_EMPTY()
+#else /* !LWIP_TCP || !TCP_QUEUE_OOSEQ || NO_SYS */
+/** Define this to 0 to prevent freeing ooseq pbufs when the PBUF_POOL is empty */
+#ifndef PBUF_POOL_FREE_OOSEQ
+#define PBUF_POOL_FREE_OOSEQ 1
+#endif /* PBUF_POOL_FREE_OOSEQ */
+
+#if PBUF_POOL_FREE_OOSEQ
+#include "lwip/tcpip.h"
+#define PBUF_POOL_IS_EMPTY() pbuf_pool_is_empty()
+static u8_t pbuf_free_ooseq_queued;
+/**
+ * Attempt to reclaim some memory from queued out-of-sequence TCP segments
+ * if we run out of pool pbufs. It's better to give priority to new packets
+ * if we're running out.
+ *
+ * This must be done in the correct thread context therefore this function
+ * can only be used with NO_SYS=0 and through tcpip_callback.
+ */
+static void
+pbuf_free_ooseq(void* arg)
+{
+  struct tcp_pcb* pcb;
+  SYS_ARCH_DECL_PROTECT(old_level);
+  LWIP_UNUSED_ARG(arg);
+
+  SYS_ARCH_PROTECT(old_level);
+  pbuf_free_ooseq_queued = 0;
+  SYS_ARCH_UNPROTECT(old_level);
+
+  for (pcb = tcp_active_pcbs; NULL != pcb; pcb = pcb->next) {
+    if (NULL != pcb->ooseq) {
+      /** Free the ooseq pbufs of one PCB only */
+      LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_free_ooseq: freeing out-of-sequence pbufs\n"));
+      tcp_segs_free(pcb->ooseq);
+      pcb->ooseq = NULL;
+      return;
+    }
+  }
+}
+
+/** Queue a call to pbuf_free_ooseq if not already queued. */
+static void
+pbuf_pool_is_empty(void)
+{
+  u8_t queued;
+  SYS_ARCH_DECL_PROTECT(old_level);
+
+  SYS_ARCH_PROTECT(old_level);
+  queued = pbuf_free_ooseq_queued;
+  pbuf_free_ooseq_queued = 1;
+  SYS_ARCH_UNPROTECT(old_level);
+
+  if(!queued) {
+    /* queue a call to pbuf_free_ooseq if not already queued */
+    if(tcpip_callback_with_block(pbuf_free_ooseq, NULL, 0) != ERR_OK) {
+      SYS_ARCH_PROTECT(old_level);
+      pbuf_free_ooseq_queued = 0;
+      SYS_ARCH_UNPROTECT(old_level);
+    }
+  }
+}
+#endif /* PBUF_POOL_FREE_OOSEQ */
+#endif /* !LWIP_TCP || !TCP_QUEUE_OOSEQ || NO_SYS */
+
+/**
+ * Allocates a pbuf of the given type (possibly a chain for PBUF_POOL type).
+ *
+ * The actual memory allocated for the pbuf is determined by the
+ * layer at which the pbuf is allocated and the requested size
+ * (from the size parameter).
+ *
+ * @param layer flag to define header size
+ * @param length size of the pbuf's payload
+ * @param type this parameter decides how and where the pbuf
+ * should be allocated as follows:
+ *
+ * - PBUF_RAM: buffer memory for pbuf is allocated as one large
+ *             chunk. This includes protocol headers as well.
+ * - PBUF_ROM: no buffer memory is allocated for the pbuf, even for
+ *             protocol headers. Additional headers must be prepended
+ *             by allocating another pbuf and chain in to the front of
+ *             the ROM pbuf. It is assumed that the memory used is really
+ *             similar to ROM in that it is immutable and will not be
+ *             changed. Memory which is dynamic should generally not
+ *             be attached to PBUF_ROM pbufs. Use PBUF_REF instead.
+ * - PBUF_REF: no buffer memory is allocated for the pbuf, even for
+ *             protocol headers. It is assumed that the pbuf is only
+ *             being used in a single thread. If the pbuf gets queued,
+ *             then pbuf_take should be called to copy the buffer.
+ * - PBUF_POOL: the pbuf is allocated as a pbuf chain, with pbufs from
+ *              the pbuf pool that is allocated during pbuf_init().
+ *
+ * @return the allocated pbuf. If multiple pbufs where allocated, this
+ * is the first pbuf of a pbuf chain.
+ */
+struct pbuf *
+pbuf_alloc(pbuf_layer layer, u16_t length, pbuf_type type)
+{
+  struct pbuf *p, *q, *r;
+  u16_t offset;
+  s32_t rem_len; /* remaining length */
+  LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloc(length=%"U16_F")\n", length));
+
+  /* determine header offset */
+  offset = 0;
+  switch (layer) {
+  case PBUF_TRANSPORT:
+    /* add room for transport (often TCP) layer header */
+    offset += PBUF_TRANSPORT_HLEN;
+    /* FALLTHROUGH */
+  case PBUF_IP:
+    /* add room for IP layer header */
+    offset += PBUF_IP_HLEN;
+    /* FALLTHROUGH */
+  case PBUF_LINK:
+    /* add room for link layer header */
+    offset += PBUF_LINK_HLEN;
+    break;
+  case PBUF_RAW:
+    break;
+  default:
+    LWIP_ASSERT("pbuf_alloc: bad pbuf layer", 0);
+    return NULL;
+  }
+
+  switch (type) {
+  case PBUF_POOL:
+    /* allocate head of pbuf chain into p */
+    p = (struct pbuf *)memp_malloc(MEMP_PBUF_POOL);
+    LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloc: allocated pbuf %p\n", (void *)p));
+    if (p == NULL) {
+      PBUF_POOL_IS_EMPTY();
+      return NULL;
+    }
+    p->type = type;
+    p->next = NULL;
+
+    /* make the payload pointer point 'offset' bytes into pbuf data memory */
+    p->payload = LWIP_MEM_ALIGN((void *)((u8_t *)p + (SIZEOF_STRUCT_PBUF + offset)));
+    LWIP_ASSERT("pbuf_alloc: pbuf p->payload properly aligned",
+            ((mem_ptr_t)p->payload % MEM_ALIGNMENT) == 0);
+    /* the total length of the pbuf chain is the requested size */
+    p->tot_len = length;
+    /* set the length of the first pbuf in the chain */
+    p->len = LWIP_MIN(length, PBUF_POOL_BUFSIZE_ALIGNED - LWIP_MEM_ALIGN_SIZE(offset));
+    LWIP_ASSERT("check p->payload + p->len does not overflow pbuf",
+                ((u8_t*)p->payload + p->len <=
+                 (u8_t*)p + SIZEOF_STRUCT_PBUF + PBUF_POOL_BUFSIZE_ALIGNED));
+    LWIP_ASSERT("PBUF_POOL_BUFSIZE must be bigger than MEM_ALIGNMENT",
+      (PBUF_POOL_BUFSIZE_ALIGNED - LWIP_MEM_ALIGN_SIZE(offset)) > 0 );
+    /* set reference count (needed here in case we fail) */
+    p->ref = 1;
+
+    /* now allocate the tail of the pbuf chain */
+
+    /* remember first pbuf for linkage in next iteration */
+    r = p;
+    /* remaining length to be allocated */
+    rem_len = length - p->len;
+    /* any remaining pbufs to be allocated? */
+    while (rem_len > 0) {
+      q = (struct pbuf *)memp_malloc(MEMP_PBUF_POOL);
+      if (q == NULL) {
+        PBUF_POOL_IS_EMPTY();
+        /* free chain so far allocated */
+        pbuf_free(p);
+        /* bail out unsuccesfully */
+        return NULL;
+      }
+      q->type = type;
+      q->flags = 0;
+      q->next = NULL;
+      /* make previous pbuf point to this pbuf */
+      r->next = q;
+      /* set total length of this pbuf and next in chain */
+      LWIP_ASSERT("rem_len < max_u16_t", rem_len < 0xffff);
+      q->tot_len = (u16_t)rem_len;
+      /* this pbuf length is pool size, unless smaller sized tail */
+      q->len = LWIP_MIN((u16_t)rem_len, PBUF_POOL_BUFSIZE_ALIGNED);
+      q->payload = (void *)((u8_t *)q + SIZEOF_STRUCT_PBUF);
+      LWIP_ASSERT("pbuf_alloc: pbuf q->payload properly aligned",
+              ((mem_ptr_t)q->payload % MEM_ALIGNMENT) == 0);
+      LWIP_ASSERT("check p->payload + p->len does not overflow pbuf",
+                  ((u8_t*)p->payload + p->len <=
+                   (u8_t*)p + SIZEOF_STRUCT_PBUF + PBUF_POOL_BUFSIZE_ALIGNED));
+      q->ref = 1;
+      /* calculate remaining length to be allocated */
+      rem_len -= q->len;
+      /* remember this pbuf for linkage in next iteration */
+      r = q;
+    }
+    /* end of chain */
+    /*r->next = NULL;*/
+
+    break;
+  case PBUF_RAM:
+    /* If pbuf is to be allocated in RAM, allocate memory for it. */
+    p = (struct pbuf*)mem_malloc(LWIP_MEM_ALIGN_SIZE(SIZEOF_STRUCT_PBUF + offset) + LWIP_MEM_ALIGN_SIZE(length));
+    if (p == NULL) {
+      return NULL;
+    }
+    /* Set up internal structure of the pbuf. */
+    p->payload = LWIP_MEM_ALIGN((void *)((u8_t *)p + SIZEOF_STRUCT_PBUF + offset));
+    p->len = p->tot_len = length;
+    p->next = NULL;
+    p->type = type;
+
+    LWIP_ASSERT("pbuf_alloc: pbuf->payload properly aligned",
+           ((mem_ptr_t)p->payload % MEM_ALIGNMENT) == 0);
+    break;
+  /* pbuf references existing (non-volatile static constant) ROM payload? */
+  case PBUF_ROM:
+  /* pbuf references existing (externally allocated) RAM payload? */
+  case PBUF_REF:
+    /* only allocate memory for the pbuf structure */
+    p = (struct pbuf *)memp_malloc(MEMP_PBUF);
+    if (p == NULL) {
+      LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
+                  ("pbuf_alloc: Could not allocate MEMP_PBUF for PBUF_%s.\n",
+                  (type == PBUF_ROM) ? "ROM" : "REF"));
+      return NULL;
+    }
+    /* caller must set this field properly, afterwards */
+    p->payload = NULL;
+    p->len = p->tot_len = length;
+    p->next = NULL;
+    p->type = type;
+    break;
+  default:
+    LWIP_ASSERT("pbuf_alloc: erroneous type", 0);
+    return NULL;
+  }
+  /* set reference count */
+  p->ref = 1;
+  /* set flags */
+  p->flags = 0;
+  LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloc(length=%"U16_F") == %p\n", length, (void *)p));
+  return p;
+}
+
+#if LWIP_SUPPORT_CUSTOM_PBUF
+/** Initialize a custom pbuf (already allocated).
+ *
+ * @param layer flag to define header size
+ * @param length size of the pbuf's payload
+ * @param type type of the pbuf (only used to treat the pbuf accordingly, as
+ *        this function allocates no memory)
+ * @param p pointer to the custom pbuf to initialize (already allocated)
+ * @param payload_mem pointer to the buffer that is used for payload and headers,
+ *        must be at least big enough to hold 'length' plus the header size,
+ *        may be NULL if set later
+ * @param payload_mem_len the size of the 'payload_mem' buffer, must be at least
+ *        big enough to hold 'length' plus the header size
+ */
+struct pbuf*
+pbuf_alloced_custom(pbuf_layer l, u16_t length, pbuf_type type, struct pbuf_custom *p,
+                    void *payload_mem, u16_t payload_mem_len)
+{
+  u16_t offset;
+  LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloced_custom(length=%"U16_F")\n", length));
+
+  /* determine header offset */
+  offset = 0;
+  switch (l) {
+  case PBUF_TRANSPORT:
+    /* add room for transport (often TCP) layer header */
+    offset += PBUF_TRANSPORT_HLEN;
+    /* FALLTHROUGH */
+  case PBUF_IP:
+    /* add room for IP layer header */
+    offset += PBUF_IP_HLEN;
+    /* FALLTHROUGH */
+  case PBUF_LINK:
+    /* add room for link layer header */
+    offset += PBUF_LINK_HLEN;
+    break;
+  case PBUF_RAW:
+    break;
+  default:
+    LWIP_ASSERT("pbuf_alloced_custom: bad pbuf layer", 0);
+    return NULL;
+  }
+
+  if (LWIP_MEM_ALIGN_SIZE(offset) + length < payload_mem_len) {
+    LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_LEVEL_WARNING, ("pbuf_alloced_custom(length=%"U16_F") buffer too short\n", length));
+    return NULL;
+  }
+
+  p->pbuf.next = NULL;
+  if (payload_mem != NULL) {
+    p->pbuf.payload = LWIP_MEM_ALIGN((void *)((u8_t *)payload_mem + offset));
+  } else {
+    p->pbuf.payload = NULL;
+  }
+  p->pbuf.flags = PBUF_FLAG_IS_CUSTOM;
+  p->pbuf.len = p->pbuf.tot_len = length;
+  p->pbuf.type = type;
+  p->pbuf.ref = 1;
+  return &p->pbuf;
+}
+#endif /* LWIP_SUPPORT_CUSTOM_PBUF */
+
+/**
+ * Shrink a pbuf chain to a desired length.
+ *
+ * @param p pbuf to shrink.
+ * @param new_len desired new length of pbuf chain
+ *
+ * Depending on the desired length, the first few pbufs in a chain might
+ * be skipped and left unchanged. The new last pbuf in the chain will be
+ * resized, and any remaining pbufs will be freed.
+ *
+ * @note If the pbuf is ROM/REF, only the ->tot_len and ->len fields are adjusted.
+ * @note May not be called on a packet queue.
+ *
+ * @note Despite its name, pbuf_realloc cannot grow the size of a pbuf (chain).
+ */
+void
+pbuf_realloc(struct pbuf *p, u16_t new_len)
+{
+  struct pbuf *q;
+  u16_t rem_len; /* remaining length */
+  s32_t grow;
+
+  LWIP_ASSERT("pbuf_realloc: p != NULL", p != NULL);
+  LWIP_ASSERT("pbuf_realloc: sane p->type", p->type == PBUF_POOL ||
+              p->type == PBUF_ROM ||
+              p->type == PBUF_RAM ||
+              p->type == PBUF_REF);
+
+  /* desired length larger than current length? */
+  if (new_len >= p->tot_len) {
+    /* enlarging not yet supported */
+    return;
+  }
+
+  /* the pbuf chain grows by (new_len - p->tot_len) bytes
+   * (which may be negative in case of shrinking) */
+  grow = new_len - p->tot_len;
+
+  /* first, step over any pbufs that should remain in the chain */
+  rem_len = new_len;
+  q = p;
+  /* should this pbuf be kept? */
+  while (rem_len > q->len) {
+    /* decrease remaining length by pbuf length */
+    rem_len -= q->len;
+    /* decrease total length indicator */
+    LWIP_ASSERT("grow < max_u16_t", grow < 0xffff);
+    q->tot_len += (u16_t)grow;
+    /* proceed to next pbuf in chain */
+    q = q->next;
+    LWIP_ASSERT("pbuf_realloc: q != NULL", q != NULL);
+  }
+  /* we have now reached the new last pbuf (in q) */
+  /* rem_len == desired length for pbuf q */
+
+  /* shrink allocated memory for PBUF_RAM */
+  /* (other types merely adjust their length fields */
+  if ((q->type == PBUF_RAM) && (rem_len != q->len)) {
+    /* reallocate and adjust the length of the pbuf that will be split */
+    q = (struct pbuf *)mem_trim(q, (u16_t)((u8_t *)q->payload - (u8_t *)q) + rem_len);
+    LWIP_ASSERT("mem_trim returned q == NULL", q != NULL);
+  }
+  /* adjust length fields for new last pbuf */
+  q->len = rem_len;
+  q->tot_len = q->len;
+
+  /* any remaining pbufs in chain? */
+  if (q->next != NULL) {
+    /* free remaining pbufs in chain */
+    pbuf_free(q->next);
+  }
+  /* q is last packet in chain */
+  q->next = NULL;
+
+}
+
+/**
+ * Adjusts the payload pointer to hide or reveal headers in the payload.
+ *
+ * Adjusts the ->payload pointer so that space for a header
+ * (dis)appears in the pbuf payload.
+ *
+ * The ->payload, ->tot_len and ->len fields are adjusted.
+ *
+ * @param p pbuf to change the header size.
+ * @param header_size_increment Number of bytes to increment header size which
+ * increases the size of the pbuf. New space is on the front.
+ * (Using a negative value decreases the header size.)
+ * If hdr_size_inc is 0, this function does nothing and returns succesful.
+ *
+ * PBUF_ROM and PBUF_REF type buffers cannot have their sizes increased, so
+ * the call will fail. A check is made that the increase in header size does
+ * not move the payload pointer in front of the start of the buffer.
+ * @return non-zero on failure, zero on success.
+ *
+ */
+u8_t
+pbuf_header(struct pbuf *p, s16_t header_size_increment)
+{
+  u16_t type;
+  void *payload;
+  u16_t increment_magnitude;
+
+  LWIP_ASSERT("p != NULL", p != NULL);
+  if ((header_size_increment == 0) || (p == NULL)) {
+    return 0;
+  }
+ 
+  if (header_size_increment < 0){
+    increment_magnitude = -header_size_increment;
+    /* Check that we aren't going to move off the end of the pbuf */
+    LWIP_ERROR("increment_magnitude <= p->len", (increment_magnitude <= p->len), return 1;);
+  } else {
+    increment_magnitude = header_size_increment;
+#if 0
+    /* Can't assert these as some callers speculatively call
+         pbuf_header() to see if it's OK.  Will return 1 below instead. */
+    /* Check that we've got the correct type of pbuf to work with */
+    LWIP_ASSERT("p->type == PBUF_RAM || p->type == PBUF_POOL", 
+                p->type == PBUF_RAM || p->type == PBUF_POOL);
+    /* Check that we aren't going to move off the beginning of the pbuf */
+    LWIP_ASSERT("p->payload - increment_magnitude >= p + SIZEOF_STRUCT_PBUF",
+                (u8_t *)p->payload - increment_magnitude >= (u8_t *)p + SIZEOF_STRUCT_PBUF);
+#endif
+  }
+
+  type = p->type;
+  /* remember current payload pointer */
+  payload = p->payload;
+
+  /* pbuf types containing payloads? */
+  if (type == PBUF_RAM || type == PBUF_POOL) {
+    /* set new payload pointer */
+    p->payload = (u8_t *)p->payload - header_size_increment;
+    /* boundary check fails? */
+    if ((u8_t *)p->payload < (u8_t *)p + SIZEOF_STRUCT_PBUF) {
+      LWIP_DEBUGF( PBUF_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
+        ("pbuf_header: failed as %p < %p (not enough space for new header size)\n",
+        (void *)p->payload, (void *)(p + 1)));
+      /* restore old payload pointer */
+      p->payload = payload;
+      /* bail out unsuccesfully */
+      return 1;
+    }
+  /* pbuf types refering to external payloads? */
+  } else if (type == PBUF_REF || type == PBUF_ROM) {
+    /* hide a header in the payload? */
+    if ((header_size_increment < 0) && (increment_magnitude <= p->len)) {
+      /* increase payload pointer */
+      p->payload = (u8_t *)p->payload - header_size_increment;
+    } else {
+      /* cannot expand payload to front (yet!)
+       * bail out unsuccesfully */
+      return 1;
+    }
+  } else {
+    /* Unknown type */
+    LWIP_ASSERT("bad pbuf type", 0);
+    return 1;
+  }
+  /* modify pbuf length fields */
+  p->len += header_size_increment;
+  p->tot_len += header_size_increment;
+
+  LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_header: old %p new %p (%"S16_F")\n",
+    (void *)payload, (void *)p->payload, header_size_increment));
+
+  return 0;
+}
+
+/**
+ * Dereference a pbuf chain or queue and deallocate any no-longer-used
+ * pbufs at the head of this chain or queue.
+ *
+ * Decrements the pbuf reference count. If it reaches zero, the pbuf is
+ * deallocated.
+ *
+ * For a pbuf chain, this is repeated for each pbuf in the chain,
+ * up to the first pbuf which has a non-zero reference count after
+ * decrementing. So, when all reference counts are one, the whole
+ * chain is free'd.
+ *
+ * @param p The pbuf (chain) to be dereferenced.
+ *
+ * @return the number of pbufs that were de-allocated
+ * from the head of the chain.
+ *
+ * @note MUST NOT be called on a packet queue (Not verified to work yet).
+ * @note the reference counter of a pbuf equals the number of pointers
+ * that refer to the pbuf (or into the pbuf).
+ *
+ * @internal examples:
+ *
+ * Assuming existing chains a->b->c with the following reference
+ * counts, calling pbuf_free(a) results in:
+ * 
+ * 1->2->3 becomes ...1->3
+ * 3->3->3 becomes 2->3->3
+ * 1->1->2 becomes ......1
+ * 2->1->1 becomes 1->1->1
+ * 1->1->1 becomes .......
+ *
+ */
+u8_t
+pbuf_free(struct pbuf *p)
+{
+  u16_t type;
+  struct pbuf *q;
+  u8_t count;
+
+  if (p == NULL) {
+    LWIP_ASSERT("p != NULL", p != NULL);
+    /* if assertions are disabled, proceed with debug output */
+    LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
+      ("pbuf_free(p == NULL) was called.\n"));
+    return 0;
+  }
+  LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_free(%p)\n", (void *)p));
+
+  PERF_START;
+
+  LWIP_ASSERT("pbuf_free: sane type",
+    p->type == PBUF_RAM || p->type == PBUF_ROM ||
+    p->type == PBUF_REF || p->type == PBUF_POOL);
+
+  count = 0;
+  /* de-allocate all consecutive pbufs from the head of the chain that
+   * obtain a zero reference count after decrementing*/
+  while (p != NULL) {
+    u16_t ref;
+    SYS_ARCH_DECL_PROTECT(old_level);
+    /* Since decrementing ref cannot be guaranteed to be a single machine operation
+     * we must protect it. We put the new ref into a local variable to prevent
+     * further protection. */
+    SYS_ARCH_PROTECT(old_level);
+    /* all pbufs in a chain are referenced at least once */
+    LWIP_ASSERT("pbuf_free: p->ref > 0", p->ref > 0);
+    /* decrease reference count (number of pointers to pbuf) */
+    ref = --(p->ref);
+    SYS_ARCH_UNPROTECT(old_level);
+    /* this pbuf is no longer referenced to? */
+    if (ref == 0) {
+      /* remember next pbuf in chain for next iteration */
+      q = p->next;
+      LWIP_DEBUGF( PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_free: deallocating %p\n", (void *)p));
+      type = p->type;
+#if LWIP_SUPPORT_CUSTOM_PBUF
+      /* is this a custom pbuf? */
+      if ((p->flags & PBUF_FLAG_IS_CUSTOM) != 0) {
+        struct pbuf_custom *pc = (struct pbuf_custom*)p;
+        LWIP_ASSERT("pc->custom_free_function != NULL", pc->custom_free_function != NULL);
+        pc->custom_free_function(p);
+      } else
+#endif /* LWIP_SUPPORT_CUSTOM_PBUF */
+      {
+        /* is this a pbuf from the pool? */
+        if (type == PBUF_POOL) {
+          memp_free(MEMP_PBUF_POOL, p);
+        /* is this a ROM or RAM referencing pbuf? */
+        } else if (type == PBUF_ROM || type == PBUF_REF) {
+          memp_free(MEMP_PBUF, p);
+        /* type == PBUF_RAM */
+        } else {
+          mem_free(p);
+        }
+      }
+      count++;
+      /* proceed to next pbuf */
+      p = q;
+    /* p->ref > 0, this pbuf is still referenced to */
+    /* (and so the remaining pbufs in chain as well) */
+    } else {
+      LWIP_DEBUGF( PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_free: %p has ref %"U16_F", ending here.\n", (void *)p, ref));
+      /* stop walking through the chain */
+      p = NULL;
+    }
+  }
+  PERF_STOP("pbuf_free");
+  /* return number of de-allocated pbufs */
+  return count;
+}
+
+/**
+ * Count number of pbufs in a chain
+ *
+ * @param p first pbuf of chain
+ * @return the number of pbufs in a chain
+ */
+
+u8_t
+pbuf_clen(struct pbuf *p)
+{
+  u8_t len;
+
+  len = 0;
+  while (p != NULL) {
+    ++len;
+    p = p->next;
+  }
+  return len;
+}
+
+/**
+ * Increment the reference count of the pbuf.
+ *
+ * @param p pbuf to increase reference counter of
+ *
+ */
+void
+pbuf_ref(struct pbuf *p)
+{
+  SYS_ARCH_DECL_PROTECT(old_level);
+  /* pbuf given? */
+  if (p != NULL) {
+    SYS_ARCH_PROTECT(old_level);
+    ++(p->ref);
+    SYS_ARCH_UNPROTECT(old_level);
+  }
+}
+
+/**
+ * Concatenate two pbufs (each may be a pbuf chain) and take over
+ * the caller's reference of the tail pbuf.
+ * 
+ * @note The caller MAY NOT reference the tail pbuf afterwards.
+ * Use pbuf_chain() for that purpose.
+ * 
+ * @see pbuf_chain()
+ */
+
+void
+pbuf_cat(struct pbuf *h, struct pbuf *t)
+{
+  struct pbuf *p;
+
+  LWIP_ERROR("(h != NULL) && (t != NULL) (programmer violates API)",
+             ((h != NULL) && (t != NULL)), return;);
+
+  /* proceed to last pbuf of chain */
+  for (p = h; p->next != NULL; p = p->next) {
+    /* add total length of second chain to all totals of first chain */
+    p->tot_len += t->tot_len;
+  }
+  /* { p is last pbuf of first h chain, p->next == NULL } */
+  LWIP_ASSERT("p->tot_len == p->len (of last pbuf in chain)", p->tot_len == p->len);
+  LWIP_ASSERT("p->next == NULL", p->next == NULL);
+  /* add total length of second chain to last pbuf total of first chain */
+  p->tot_len += t->tot_len;
+  /* chain last pbuf of head (p) with first of tail (t) */
+  p->next = t;
+  /* p->next now references t, but the caller will drop its reference to t,
+   * so netto there is no change to the reference count of t.
+   */
+}
+
+/**
+ * Chain two pbufs (or pbuf chains) together.
+ * 
+ * The caller MUST call pbuf_free(t) once it has stopped
+ * using it. Use pbuf_cat() instead if you no longer use t.
+ * 
+ * @param h head pbuf (chain)
+ * @param t tail pbuf (chain)
+ * @note The pbufs MUST belong to the same packet.
+ * @note MAY NOT be called on a packet queue.
+ *
+ * The ->tot_len fields of all pbufs of the head chain are adjusted.
+ * The ->next field of the last pbuf of the head chain is adjusted.
+ * The ->ref field of the first pbuf of the tail chain is adjusted.
+ *
+ */
+void
+pbuf_chain(struct pbuf *h, struct pbuf *t)
+{
+  pbuf_cat(h, t);
+  /* t is now referenced by h */
+  pbuf_ref(t);
+  LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_chain: %p references %p\n", (void *)h, (void *)t));
+}
+
+/**
+ * Dechains the first pbuf from its succeeding pbufs in the chain.
+ *
+ * Makes p->tot_len field equal to p->len.
+ * @param p pbuf to dechain
+ * @return remainder of the pbuf chain, or NULL if it was de-allocated.
+ * @note May not be called on a packet queue.
+ */
+struct pbuf *
+pbuf_dechain(struct pbuf *p)
+{
+  struct pbuf *q;
+  u8_t tail_gone = 1;
+  /* tail */
+  q = p->next;
+  /* pbuf has successor in chain? */
+  if (q != NULL) {
+    /* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */
+    LWIP_ASSERT("p->tot_len == p->len + q->tot_len", q->tot_len == p->tot_len - p->len);
+    /* enforce invariant if assertion is disabled */
+    q->tot_len = p->tot_len - p->len;
+    /* decouple pbuf from remainder */
+    p->next = NULL;
+    /* total length of pbuf p is its own length only */
+    p->tot_len = p->len;
+    /* q is no longer referenced by p, free it */
+    LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_dechain: unreferencing %p\n", (void *)q));
+    tail_gone = pbuf_free(q);
+    if (tail_gone > 0) {
+      LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE,
+                  ("pbuf_dechain: deallocated %p (as it is no longer referenced)\n", (void *)q));
+    }
+    /* return remaining tail or NULL if deallocated */
+  }
+  /* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */
+  LWIP_ASSERT("p->tot_len == p->len", p->tot_len == p->len);
+  return ((tail_gone > 0) ? NULL : q);
+}
+
+/**
+ *
+ * Create PBUF_RAM copies of pbufs.
+ *
+ * Used to queue packets on behalf of the lwIP stack, such as
+ * ARP based queueing.
+ *
+ * @note You MUST explicitly use p = pbuf_take(p);
+ *
+ * @note Only one packet is copied, no packet queue!
+ *
+ * @param p_to pbuf destination of the copy
+ * @param p_from pbuf source of the copy
+ *
+ * @return ERR_OK if pbuf was copied
+ *         ERR_ARG if one of the pbufs is NULL or p_to is not big
+ *                 enough to hold p_from
+ */
+err_t
+pbuf_copy(struct pbuf *p_to, struct pbuf *p_from)
+{
+  u16_t offset_to=0, offset_from=0, len;
+
+  LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_copy(%p, %p)\n",
+    (void*)p_to, (void*)p_from));
+
+  /* is the target big enough to hold the source? */
+  LWIP_ERROR("pbuf_copy: target not big enough to hold source", ((p_to != NULL) &&
+             (p_from != NULL) && (p_to->tot_len >= p_from->tot_len)), return ERR_ARG;);
+
+  /* iterate through pbuf chain */
+  do
+  {
+    LWIP_ASSERT("p_to != NULL", p_to != NULL);
+    /* copy one part of the original chain */
+    if ((p_to->len - offset_to) >= (p_from->len - offset_from)) {
+      /* complete current p_from fits into current p_to */
+      len = p_from->len - offset_from;
+    } else {
+      /* current p_from does not fit into current p_to */
+      len = p_to->len - offset_to;
+    }
+    MEMCPY((u8_t*)p_to->payload + offset_to, (u8_t*)p_from->payload + offset_from, len);
+    offset_to += len;
+    offset_from += len;
+    LWIP_ASSERT("offset_to <= p_to->len", offset_to <= p_to->len);
+    if (offset_to == p_to->len) {
+      /* on to next p_to (if any) */
+      offset_to = 0;
+      p_to = p_to->next;
+    }
+    LWIP_ASSERT("offset_from <= p_from->len", offset_from <= p_from->len);
+    if (offset_from >= p_from->len) {
+      /* on to next p_from (if any) */
+      offset_from = 0;
+      p_from = p_from->next;
+    }
+
+    if((p_from != NULL) && (p_from->len == p_from->tot_len)) {
+      /* don't copy more than one packet! */
+      LWIP_ERROR("pbuf_copy() does not allow packet queues!\n",
+                 (p_from->next == NULL), return ERR_VAL;);
+    }
+    if((p_to != NULL) && (p_to->len == p_to->tot_len)) {
+      /* don't copy more than one packet! */
+      LWIP_ERROR("pbuf_copy() does not allow packet queues!\n",
+                  (p_to->next == NULL), return ERR_VAL;);
+    }
+  } while (p_from);
+  LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_copy: end of chain reached.\n"));
+  return ERR_OK;
+}
+
+/**
+ * Copy (part of) the contents of a packet buffer
+ * to an application supplied buffer.
+ *
+ * @param buf the pbuf from which to copy data
+ * @param dataptr the application supplied buffer
+ * @param len length of data to copy (dataptr must be big enough). No more 
+ * than buf->tot_len will be copied, irrespective of len
+ * @param offset offset into the packet buffer from where to begin copying len bytes
+ * @return the number of bytes copied, or 0 on failure
+ */
+u16_t
+pbuf_copy_partial(struct pbuf *buf, void *dataptr, u16_t len, u16_t offset)
+{
+  struct pbuf *p;
+  u16_t left;
+  u16_t buf_copy_len;
+  u16_t copied_total = 0;
+
+  LWIP_ERROR("pbuf_copy_partial: invalid buf", (buf != NULL), return 0;);
+  LWIP_ERROR("pbuf_copy_partial: invalid dataptr", (dataptr != NULL), return 0;);
+
+  left = 0;
+
+  if((buf == NULL) || (dataptr == NULL)) {
+    return 0;
+  }
+
+  /* Note some systems use byte copy if dataptr or one of the pbuf payload pointers are unaligned. */
+  for(p = buf; len != 0 && p != NULL; p = p->next) {
+    if ((offset != 0) && (offset >= p->len)) {
+      /* don't copy from this buffer -> on to the next */
+      offset -= p->len;
+    } else {
+      /* copy from this buffer. maybe only partially. */
+      buf_copy_len = p->len - offset;
+      if (buf_copy_len > len)
+          buf_copy_len = len;
+      /* copy the necessary parts of the buffer */
+      MEMCPY(&((char*)dataptr)[left], &((char*)p->payload)[offset], buf_copy_len);
+      copied_total += buf_copy_len;
+      left += buf_copy_len;
+      len -= buf_copy_len;
+      offset = 0;
+    }
+  }
+  return copied_total;
+}
+
+/**
+ * Copy application supplied data into a pbuf.
+ * This function can only be used to copy the equivalent of buf->tot_len data.
+ *
+ * @param buf pbuf to fill with data
+ * @param dataptr application supplied data buffer
+ * @param len length of the application supplied data buffer
+ *
+ * @return ERR_OK if successful, ERR_MEM if the pbuf is not big enough
+ */
+err_t
+pbuf_take(struct pbuf *buf, const void *dataptr, u16_t len)
+{
+  struct pbuf *p;
+  u16_t buf_copy_len;
+  u16_t total_copy_len = len;
+  u16_t copied_total = 0;
+
+  LWIP_ERROR("pbuf_take: invalid buf", (buf != NULL), return 0;);
+  LWIP_ERROR("pbuf_take: invalid dataptr", (dataptr != NULL), return 0;);
+
+  if ((buf == NULL) || (dataptr == NULL) || (buf->tot_len < len)) {
+    return ERR_ARG;
+  }
+
+  /* Note some systems use byte copy if dataptr or one of the pbuf payload pointers are unaligned. */
+  for(p = buf; total_copy_len != 0; p = p->next) {
+    LWIP_ASSERT("pbuf_take: invalid pbuf", p != NULL);
+    buf_copy_len = total_copy_len;
+    if (buf_copy_len > p->len) {
+      /* this pbuf cannot hold all remaining data */
+      buf_copy_len = p->len;
+    }
+    /* copy the necessary parts of the buffer */
+    MEMCPY(p->payload, &((char*)dataptr)[copied_total], buf_copy_len);
+    total_copy_len -= buf_copy_len;
+    copied_total += buf_copy_len;
+  }
+  LWIP_ASSERT("did not copy all data", total_copy_len == 0 && copied_total == len);
+  return ERR_OK;
+}
+
+/**
+ * Creates a single pbuf out of a queue of pbufs.
+ *
+ * @remark: Either the source pbuf 'p' is freed by this function or the original
+ *          pbuf 'p' is returned, therefore the caller has to check the result!
+ *
+ * @param p the source pbuf
+ * @param layer pbuf_layer of the new pbuf
+ *
+ * @return a new, single pbuf (p->next is NULL)
+ *         or the old pbuf if allocation fails
+ */
+struct pbuf*
+pbuf_coalesce(struct pbuf *p, pbuf_layer layer)
+{
+  struct pbuf *q;
+  err_t err;
+  if (p->next == NULL) {
+    return p;
+  }
+  q = pbuf_alloc(layer, p->tot_len, PBUF_RAM);
+  if (q == NULL) {
+    /* @todo: what do we do now? */
+    return p;
+  }
+  err = pbuf_copy(q, p);
+  LWIP_ASSERT("pbuf_copy failed", err == ERR_OK);
+  pbuf_free(p);
+  return q;
+}
+
+#if LWIP_CHECKSUM_ON_COPY
+/**
+ * Copies data into a single pbuf (*not* into a pbuf queue!) and updates
+ * the checksum while copying
+ *
+ * @param p the pbuf to copy data into
+ * @param start_offset offset of p->payload where to copy the data to
+ * @param dataptr data to copy into the pbuf
+ * @param len length of data to copy into the pbuf
+ * @param chksum pointer to the checksum which is updated
+ * @return ERR_OK if successful, another error if the data does not fit
+ *         within the (first) pbuf (no pbuf queues!)
+ */
+err_t
+pbuf_fill_chksum(struct pbuf *p, u16_t start_offset, const void *dataptr,
+                 u16_t len, u16_t *chksum)
+{
+  u32_t acc;
+  u16_t copy_chksum;
+  char *dst_ptr;
+  LWIP_ASSERT("p != NULL", p != NULL);
+  LWIP_ASSERT("dataptr != NULL", dataptr != NULL);
+  LWIP_ASSERT("chksum != NULL", chksum != NULL);
+  LWIP_ASSERT("len != 0", len != 0);
+
+  if ((start_offset >= p->len) || (start_offset + len > p->len)) {
+    return ERR_ARG;
+  }
+
+  dst_ptr = ((char*)p->payload) + start_offset;
+  copy_chksum = LWIP_CHKSUM_COPY(dst_ptr, dataptr, len);
+  if ((start_offset & 1) != 0) {
+    copy_chksum = SWAP_BYTES_IN_WORD(copy_chksum);
+  }
+  acc = *chksum;
+  acc += copy_chksum;
+  *chksum = FOLD_U32T(acc);
+  return ERR_OK;
+}
+#endif /* LWIP_CHECKSUM_ON_COPY */
+
+ /** Get one byte from the specified position in a pbuf
+ * WARNING: returns zero for offset >= p->tot_len
+ *
+ * @param p pbuf to parse
+ * @param offset offset into p of the byte to return
+ * @return byte at an offset into p OR ZERO IF 'offset' >= p->tot_len
+ */
+u8_t
+pbuf_get_at(struct pbuf* p, u16_t offset)
+{
+  u16_t copy_from = offset;
+  struct pbuf* q = p;
+
+  /* get the correct pbuf */
+  while ((q != NULL) && (q->len <= copy_from)) {
+    copy_from -= q->len;
+    q = q->next;
+  }
+  /* return requested data if pbuf is OK */
+  if ((q != NULL) && (q->len > copy_from)) {
+    return ((u8_t*)q->payload)[copy_from];
+  }
+  return 0;
+}
+
+/** Compare pbuf contents at specified offset with memory s2, both of length n
+ *
+ * @param p pbuf to compare
+ * @param offset offset into p at wich to start comparing
+ * @param s2 buffer to compare
+ * @param n length of buffer to compare
+ * @return zero if equal, nonzero otherwise
+ *         (0xffff if p is too short, diffoffset+1 otherwise)
+ */
+u16_t
+pbuf_memcmp(struct pbuf* p, u16_t offset, const void* s2, u16_t n)
+{
+  u16_t start = offset;
+  struct pbuf* q = p;
+
+  /* get the correct pbuf */
+  while ((q != NULL) && (q->len <= start)) {
+    start -= q->len;
+    q = q->next;
+  }
+  /* return requested data if pbuf is OK */
+  if ((q != NULL) && (q->len > start)) {
+    u16_t i;
+    for(i = 0; i < n; i++) {
+      u8_t a = pbuf_get_at(q, start + i);
+      u8_t b = ((u8_t*)s2)[i];
+      if (a != b) {
+        return i+1;
+      }
+    }
+    return 0;
+  }
+  return 0xffff;
+}
+
+/** Find occurrence of mem (with length mem_len) in pbuf p, starting at offset
+ * start_offset.
+ *
+ * @param p pbuf to search, maximum length is 0xFFFE since 0xFFFF is used as
+ *        return value 'not found'
+ * @param mem search for the contents of this buffer
+ * @param mem_len length of 'mem'
+ * @param start_offset offset into p at which to start searching
+ * @return 0xFFFF if substr was not found in p or the index where it was found
+ */
+u16_t
+pbuf_memfind(struct pbuf* p, const void* mem, u16_t mem_len, u16_t start_offset)
+{
+  u16_t i;
+  u16_t max = p->tot_len - mem_len;
+  if (p->tot_len >= mem_len + start_offset) {
+    for(i = start_offset; i <= max; ) {
+      u16_t plus = pbuf_memcmp(p, i, mem, mem_len);
+      if (plus == 0) {
+        return i;
+      } else {
+        i += plus;
+      }
+    }
+  }
+  return 0xFFFF;
+}
+
+/** Find occurrence of substr with length substr_len in pbuf p, start at offset
+ * start_offset
+ * WARNING: in contrast to strstr(), this one does not stop at the first \0 in
+ * the pbuf/source string!
+ *
+ * @param p pbuf to search, maximum length is 0xFFFE since 0xFFFF is used as
+ *        return value 'not found'
+ * @param substr string to search for in p, maximum length is 0xFFFE
+ * @return 0xFFFF if substr was not found in p or the index where it was found
+ */
+u16_t
+pbuf_strstr(struct pbuf* p, const char* substr)
+{
+  size_t substr_len;
+  if ((substr == NULL) || (substr[0] == 0) || (p->tot_len == 0xFFFF)) {
+    return 0xFFFF;
+  }
+  substr_len = strlen(substr);
+  if (substr_len >= 0xFFFF) {
+    return 0xFFFF;
+  }
+  return pbuf_memfind(p, substr, (u16_t)substr_len, 0);
+}
diff --git a/core/lwip/src/core/raw.c b/core/lwip/src/core/raw.c
new file mode 100644
index 00000000..9fcb1003
--- /dev/null
+++ b/core/lwip/src/core/raw.c
@@ -0,0 +1,354 @@
+/**
+ * @file
+ * Implementation of raw protocol PCBs for low-level handling of
+ * different types of protocols besides (or overriding) those
+ * already available in lwIP.
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_RAW /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/def.h"
+#include "lwip/memp.h"
+#include "lwip/ip_addr.h"
+#include "lwip/netif.h"
+#include "lwip/raw.h"
+#include "lwip/stats.h"
+#include "arch/perf.h"
+
+#include <string.h>
+
+/** The list of RAW PCBs */
+static struct raw_pcb *raw_pcbs;
+
+/**
+ * Determine if in incoming IP packet is covered by a RAW PCB
+ * and if so, pass it to a user-provided receive callback function.
+ *
+ * Given an incoming IP datagram (as a chain of pbufs) this function
+ * finds a corresponding RAW PCB and calls the corresponding receive
+ * callback function.
+ *
+ * @param p pbuf to be demultiplexed to a RAW PCB.
+ * @param inp network interface on which the datagram was received.
+ * @return - 1 if the packet has been eaten by a RAW PCB receive
+ *           callback function. The caller MAY NOT not reference the
+ *           packet any longer, and MAY NOT call pbuf_free().
+ * @return - 0 if packet is not eaten (pbuf is still referenced by the
+ *           caller).
+ *
+ */
+u8_t
+raw_input(struct pbuf *p, struct netif *inp)
+{
+  struct raw_pcb *pcb, *prev;
+  struct ip_hdr *iphdr;
+  s16_t proto;
+  u8_t eaten = 0;
+
+  LWIP_UNUSED_ARG(inp);
+
+  iphdr = (struct ip_hdr *)p->payload;
+  proto = IPH_PROTO(iphdr);
+
+  prev = NULL;
+  pcb = raw_pcbs;
+  /* loop through all raw pcbs until the packet is eaten by one */
+  /* this allows multiple pcbs to match against the packet by design */
+  while ((eaten == 0) && (pcb != NULL)) {
+    if ((pcb->protocol == proto) &&
+        (ip_addr_isany(&pcb->local_ip) ||
+         ip_addr_cmp(&(pcb->local_ip), &current_iphdr_dest))) {
+#if IP_SOF_BROADCAST_RECV
+      /* broadcast filter? */
+      if ((pcb->so_options & SOF_BROADCAST) || !ip_addr_isbroadcast(&current_iphdr_dest, inp))
+#endif /* IP_SOF_BROADCAST_RECV */
+      {
+        /* receive callback function available? */
+        if (pcb->recv != NULL) {
+          /* the receive callback function did not eat the packet? */
+          if (pcb->recv(pcb->recv_arg, pcb, p, ip_current_src_addr()) != 0) {
+            /* receive function ate the packet */
+            p = NULL;
+            eaten = 1;
+            if (prev != NULL) {
+            /* move the pcb to the front of raw_pcbs so that is
+               found faster next time */
+              prev->next = pcb->next;
+              pcb->next = raw_pcbs;
+              raw_pcbs = pcb;
+            }
+          }
+        }
+        /* no receive callback function was set for this raw PCB */
+      }
+      /* drop the packet */
+    }
+    prev = pcb;
+    pcb = pcb->next;
+  }
+  return eaten;
+}
+
+/**
+ * Bind a RAW PCB.
+ *
+ * @param pcb RAW PCB to be bound with a local address ipaddr.
+ * @param ipaddr local IP address to bind with. Use IP_ADDR_ANY to
+ * bind to all local interfaces.
+ *
+ * @return lwIP error code.
+ * - ERR_OK. Successful. No error occured.
+ * - ERR_USE. The specified IP address is already bound to by
+ * another RAW PCB.
+ *
+ * @see raw_disconnect()
+ */
+err_t
+raw_bind(struct raw_pcb *pcb, ip_addr_t *ipaddr)
+{
+  ip_addr_set(&pcb->local_ip, ipaddr);
+  return ERR_OK;
+}
+
+/**
+ * Connect an RAW PCB. This function is required by upper layers
+ * of lwip. Using the raw api you could use raw_sendto() instead
+ *
+ * This will associate the RAW PCB with the remote address.
+ *
+ * @param pcb RAW PCB to be connected with remote address ipaddr and port.
+ * @param ipaddr remote IP address to connect with.
+ *
+ * @return lwIP error code
+ *
+ * @see raw_disconnect() and raw_sendto()
+ */
+err_t
+raw_connect(struct raw_pcb *pcb, ip_addr_t *ipaddr)
+{
+  ip_addr_set(&pcb->remote_ip, ipaddr);
+  return ERR_OK;
+}
+
+
+/**
+ * Set the callback function for received packets that match the
+ * raw PCB's protocol and binding. 
+ * 
+ * The callback function MUST either
+ * - eat the packet by calling pbuf_free() and returning non-zero. The
+ *   packet will not be passed to other raw PCBs or other protocol layers.
+ * - not free the packet, and return zero. The packet will be matched
+ *   against further PCBs and/or forwarded to another protocol layers.
+ * 
+ * @return non-zero if the packet was free()d, zero if the packet remains
+ * available for others.
+ */
+void
+raw_recv(struct raw_pcb *pcb, raw_recv_fn recv, void *recv_arg)
+{
+  /* remember recv() callback and user data */
+  pcb->recv = recv;
+  pcb->recv_arg = recv_arg;
+}
+
+/**
+ * Send the raw IP packet to the given address. Note that actually you cannot
+ * modify the IP headers (this is inconsistent with the receive callback where
+ * you actually get the IP headers), you can only specify the IP payload here.
+ * It requires some more changes in lwIP. (there will be a raw_send() function
+ * then.)
+ *
+ * @param pcb the raw pcb which to send
+ * @param p the IP payload to send
+ * @param ipaddr the destination address of the IP packet
+ *
+ */
+err_t
+raw_sendto(struct raw_pcb *pcb, struct pbuf *p, ip_addr_t *ipaddr)
+{
+  err_t err;
+  struct netif *netif;
+  ip_addr_t *src_ip;
+  struct pbuf *q; /* q will be sent down the stack */
+  
+  LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE, ("raw_sendto\n"));
+  
+  /* not enough space to add an IP header to first pbuf in given p chain? */
+  if (pbuf_header(p, IP_HLEN)) {
+    /* allocate header in new pbuf */
+    q = pbuf_alloc(PBUF_IP, 0, PBUF_RAM);
+    /* new header pbuf could not be allocated? */
+    if (q == NULL) {
+      LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("raw_sendto: could not allocate header\n"));
+      return ERR_MEM;
+    }
+    if (p->tot_len != 0) {
+      /* chain header q in front of given pbuf p */
+      pbuf_chain(q, p);
+    }
+    /* { first pbuf q points to header pbuf } */
+    LWIP_DEBUGF(RAW_DEBUG, ("raw_sendto: added header pbuf %p before given pbuf %p\n", (void *)q, (void *)p));
+  }  else {
+    /* first pbuf q equals given pbuf */
+    q = p;
+    if(pbuf_header(q, -IP_HLEN)) {
+      LWIP_ASSERT("Can't restore header we just removed!", 0);
+      return ERR_MEM;
+    }
+  }
+
+  if ((netif = ip_route(ipaddr)) == NULL) {
+    LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, ("raw_sendto: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+      ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
+    /* free any temporary header pbuf allocated by pbuf_header() */
+    if (q != p) {
+      pbuf_free(q);
+    }
+    return ERR_RTE;
+  }
+
+#if IP_SOF_BROADCAST
+  /* broadcast filter? */
+  if (((pcb->so_options & SOF_BROADCAST) == 0) && ip_addr_isbroadcast(ipaddr, netif)) {
+    LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, ("raw_sendto: SOF_BROADCAST not enabled on pcb %p\n", (void *)pcb));
+    /* free any temporary header pbuf allocated by pbuf_header() */
+    if (q != p) {
+      pbuf_free(q);
+    }
+    return ERR_VAL;
+  }
+#endif /* IP_SOF_BROADCAST */
+
+  if (ip_addr_isany(&pcb->local_ip)) {
+    /* use outgoing network interface IP address as source address */
+    src_ip = &(netif->ip_addr);
+  } else {
+    /* use RAW PCB local IP address as source address */
+    src_ip = &(pcb->local_ip);
+  }
+
+#if LWIP_NETIF_HWADDRHINT
+  netif->addr_hint = &(pcb->addr_hint);
+#endif /* LWIP_NETIF_HWADDRHINT*/
+  err = ip_output_if (q, src_ip, ipaddr, pcb->ttl, pcb->tos, pcb->protocol, netif);
+#if LWIP_NETIF_HWADDRHINT
+  netif->addr_hint = NULL;
+#endif /* LWIP_NETIF_HWADDRHINT*/
+
+  /* did we chain a header earlier? */
+  if (q != p) {
+    /* free the header */
+    pbuf_free(q);
+  }
+  return err;
+}
+
+/**
+ * Send the raw IP packet to the address given by raw_connect()
+ *
+ * @param pcb the raw pcb which to send
+ * @param p the IP payload to send
+ *
+ */
+err_t
+raw_send(struct raw_pcb *pcb, struct pbuf *p)
+{
+  return raw_sendto(pcb, p, &pcb->remote_ip);
+}
+
+/**
+ * Remove an RAW PCB.
+ *
+ * @param pcb RAW PCB to be removed. The PCB is removed from the list of
+ * RAW PCB's and the data structure is freed from memory.
+ *
+ * @see raw_new()
+ */
+void
+raw_remove(struct raw_pcb *pcb)
+{
+  struct raw_pcb *pcb2;
+  /* pcb to be removed is first in list? */
+  if (raw_pcbs == pcb) {
+    /* make list start at 2nd pcb */
+    raw_pcbs = raw_pcbs->next;
+    /* pcb not 1st in list */
+  } else {
+    for(pcb2 = raw_pcbs; pcb2 != NULL; pcb2 = pcb2->next) {
+      /* find pcb in raw_pcbs list */
+      if (pcb2->next != NULL && pcb2->next == pcb) {
+        /* remove pcb from list */
+        pcb2->next = pcb->next;
+      }
+    }
+  }
+  memp_free(MEMP_RAW_PCB, pcb);
+}
+
+/**
+ * Create a RAW PCB.
+ *
+ * @return The RAW PCB which was created. NULL if the PCB data structure
+ * could not be allocated.
+ *
+ * @param proto the protocol number of the IPs payload (e.g. IP_PROTO_ICMP)
+ *
+ * @see raw_remove()
+ */
+struct raw_pcb *
+raw_new(u8_t proto)
+{
+  struct raw_pcb *pcb;
+
+  LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE, ("raw_new\n"));
+
+  pcb = (struct raw_pcb *)memp_malloc(MEMP_RAW_PCB);
+  /* could allocate RAW PCB? */
+  if (pcb != NULL) {
+    /* initialize PCB to all zeroes */
+    memset(pcb, 0, sizeof(struct raw_pcb));
+    pcb->protocol = proto;
+    pcb->ttl = RAW_TTL;
+    pcb->next = raw_pcbs;
+    raw_pcbs = pcb;
+  }
+  return pcb;
+}
+
+#endif /* LWIP_RAW */
diff --git a/core/lwip/src/core/snmp/asn1_dec.c b/core/lwip/src/core/snmp/asn1_dec.c
new file mode 100644
index 00000000..1d565820
--- /dev/null
+++ b/core/lwip/src/core/snmp/asn1_dec.c
@@ -0,0 +1,657 @@
+/**
+ * @file
+ * Abstract Syntax Notation One (ISO 8824, 8825) decoding
+ *
+ * @todo not optimised (yet), favor correctness over speed, favor speed over size
+ */
+
+/*
+ * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * Author: Christiaan Simons <christiaan.simons@axon.tv>
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/snmp_asn1.h"
+
+/**
+ * Retrieves type field from incoming pbuf chain.
+ *
+ * @param p points to a pbuf holding an ASN1 coded type field
+ * @param ofs points to the offset within the pbuf chain of the ASN1 coded type field
+ * @param type return ASN1 type
+ * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode
+ */
+err_t
+snmp_asn1_dec_type(struct pbuf *p, u16_t ofs, u8_t *type)
+{
+  u16_t plen, base;
+  u8_t *msg_ptr;
+
+  plen = 0;
+  while (p != NULL)
+  {
+    base = plen;
+    plen += p->len;
+    if (ofs < plen)
+    {
+      msg_ptr = (u8_t*)p->payload;
+      msg_ptr += ofs - base;
+      *type = *msg_ptr;
+      return ERR_OK;
+    }
+    p = p->next;
+  }
+  /* p == NULL, ofs >= plen */
+  return ERR_ARG;
+}
+
+/**
+ * Decodes length field from incoming pbuf chain into host length.
+ *
+ * @param p points to a pbuf holding an ASN1 coded length
+ * @param ofs points to the offset within the pbuf chain of the ASN1 coded length
+ * @param octets_used returns number of octets used by the length code
+ * @param length return host order length, upto 64k
+ * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode
+ */
+err_t
+snmp_asn1_dec_length(struct pbuf *p, u16_t ofs, u8_t *octets_used, u16_t *length)
+{
+  u16_t plen, base;
+  u8_t *msg_ptr;
+
+  plen = 0;
+  while (p != NULL)
+  {
+    base = plen;
+    plen += p->len;
+    if (ofs < plen)
+    {
+      msg_ptr = (u8_t*)p->payload;
+      msg_ptr += ofs - base;
+
+      if (*msg_ptr < 0x80)
+      {
+        /* primitive definite length format */
+        *octets_used = 1;
+        *length = *msg_ptr;
+        return ERR_OK;
+      }
+      else if (*msg_ptr == 0x80)
+      {
+        /* constructed indefinite length format, termination with two zero octets */
+        u8_t zeros;
+        u8_t i;
+
+        *length = 0;
+        zeros = 0;
+        while (zeros != 2)
+        {
+          i = 2;
+          while (i > 0)
+          {
+            i--;
+            (*length) += 1;
+            ofs += 1;
+            if (ofs >= plen)
+            {
+              /* next octet in next pbuf */
+              p = p->next;
+              if (p == NULL) { return ERR_ARG; }
+              msg_ptr = (u8_t*)p->payload;
+              plen += p->len;
+            }
+            else
+            {
+              /* next octet in same pbuf */
+              msg_ptr++;
+            }
+            if (*msg_ptr == 0)
+            {
+              zeros++;
+              if (zeros == 2)
+              {
+                /* stop while (i > 0) */
+                i = 0;
+              }
+            }
+            else
+            {
+              zeros = 0;
+            }
+          }
+        }
+        *octets_used = 1;
+        return ERR_OK;
+      }
+      else if (*msg_ptr == 0x81)
+      {
+        /* constructed definite length format, one octet */
+        ofs += 1;
+        if (ofs >= plen)
+        {
+          /* next octet in next pbuf */
+          p = p->next;
+          if (p == NULL) { return ERR_ARG; }
+          msg_ptr = (u8_t*)p->payload;
+        }
+        else
+        {
+          /* next octet in same pbuf */
+          msg_ptr++;
+        }
+        *length = *msg_ptr;
+        *octets_used = 2;
+        return ERR_OK;
+      }
+      else if (*msg_ptr == 0x82)
+      {
+        u8_t i;
+
+        /* constructed definite length format, two octets */
+        i = 2;
+        while (i > 0)
+        {
+          i--;
+          ofs += 1;
+          if (ofs >= plen)
+          {
+            /* next octet in next pbuf */
+            p = p->next;
+            if (p == NULL) { return ERR_ARG; }
+            msg_ptr = (u8_t*)p->payload;
+            plen += p->len;
+          }
+          else
+          {
+            /* next octet in same pbuf */
+            msg_ptr++;
+          }
+          if (i == 0)
+          {
+            /* least significant length octet */
+            *length |= *msg_ptr;
+          }
+          else
+          {
+            /* most significant length octet */
+            *length = (*msg_ptr) << 8;
+          }
+        }
+        *octets_used = 3;
+        return ERR_OK;
+      }
+      else
+      {
+        /* constructed definite length format 3..127 octets, this is too big (>64k) */
+        /**  @todo: do we need to accept inefficient codings with many leading zero's? */
+        *octets_used = 1 + ((*msg_ptr) & 0x7f);
+        return ERR_ARG;
+      }
+    }
+    p = p->next;
+  }
+
+  /* p == NULL, ofs >= plen */
+  return ERR_ARG;
+}
+
+/**
+ * Decodes positive integer (counter, gauge, timeticks) into u32_t.
+ *
+ * @param p points to a pbuf holding an ASN1 coded integer
+ * @param ofs points to the offset within the pbuf chain of the ASN1 coded integer
+ * @param len length of the coded integer field
+ * @param value return host order integer
+ * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode
+ *
+ * @note ASN coded integers are _always_ signed. E.g. +0xFFFF is coded
+ * as 0x00,0xFF,0xFF. Note the leading sign octet. A positive value
+ * of 0xFFFFFFFF is preceded with 0x00 and the length is 5 octets!!
+ */
+err_t
+snmp_asn1_dec_u32t(struct pbuf *p, u16_t ofs, u16_t len, u32_t *value)
+{
+  u16_t plen, base;
+  u8_t *msg_ptr;
+
+  plen = 0;
+  while (p != NULL)
+  {
+    base = plen;
+    plen += p->len;
+    if (ofs < plen)
+    {
+      msg_ptr = (u8_t*)p->payload;
+      msg_ptr += ofs - base;
+      if ((len > 0) && (len < 6))
+      {
+        /* start from zero */
+        *value = 0;
+        if (*msg_ptr & 0x80)
+        {
+          /* negative, expecting zero sign bit! */
+          return ERR_ARG;
+        }
+        else
+        {
+          /* positive */
+          if ((len > 1) && (*msg_ptr == 0))
+          {
+            /* skip leading "sign byte" octet 0x00 */
+            len--;
+            ofs += 1;
+            if (ofs >= plen)
+            {
+              /* next octet in next pbuf */
+              p = p->next;
+              if (p == NULL) { return ERR_ARG; }
+              msg_ptr = (u8_t*)p->payload;
+              plen += p->len;
+            }
+            else
+            {
+              /* next octet in same pbuf */
+              msg_ptr++;
+            }
+          }
+        }
+        /* OR octets with value */
+        while (len > 1)
+        {
+          len--;
+          *value |= *msg_ptr;
+          *value <<= 8;
+          ofs += 1;
+          if (ofs >= plen)
+          {
+            /* next octet in next pbuf */
+            p = p->next;
+            if (p == NULL) { return ERR_ARG; }
+            msg_ptr = (u8_t*)p->payload;
+            plen += p->len;
+          }
+          else
+          {
+            /* next octet in same pbuf */
+            msg_ptr++;
+          }
+        }
+        *value |= *msg_ptr;
+        return ERR_OK;
+      }
+      else
+      {
+        return ERR_ARG;
+      }
+    }
+    p = p->next;
+  }
+  /* p == NULL, ofs >= plen */
+  return ERR_ARG;
+}
+
+/**
+ * Decodes integer into s32_t.
+ *
+ * @param p points to a pbuf holding an ASN1 coded integer
+ * @param ofs points to the offset within the pbuf chain of the ASN1 coded integer
+ * @param len length of the coded integer field
+ * @param value return host order integer
+ * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode
+ *
+ * @note ASN coded integers are _always_ signed!
+ */
+err_t
+snmp_asn1_dec_s32t(struct pbuf *p, u16_t ofs, u16_t len, s32_t *value)
+{
+  u16_t plen, base;
+  u8_t *msg_ptr;
+#if BYTE_ORDER == LITTLE_ENDIAN
+  u8_t *lsb_ptr = (u8_t*)value;
+#endif
+#if BYTE_ORDER == BIG_ENDIAN
+  u8_t *lsb_ptr = (u8_t*)value + sizeof(s32_t) - 1;
+#endif
+  u8_t sign;
+
+  plen = 0;
+  while (p != NULL)
+  {
+    base = plen;
+    plen += p->len;
+    if (ofs < plen)
+    {
+      msg_ptr = (u8_t*)p->payload;
+      msg_ptr += ofs - base;
+      if ((len > 0) && (len < 5))
+      {
+        if (*msg_ptr & 0x80)
+        {
+          /* negative, start from -1 */
+          *value = -1;
+          sign = 1;
+        }
+        else
+        {
+          /* positive, start from 0 */
+          *value = 0;
+          sign = 0;
+        }
+        /* OR/AND octets with value */
+        while (len > 1)
+        {
+          len--;
+          if (sign)
+          {
+            *lsb_ptr &= *msg_ptr;
+            *value <<= 8;
+            *lsb_ptr |= 255;
+          }
+          else
+          {
+            *lsb_ptr |= *msg_ptr;
+            *value <<= 8;
+          }
+          ofs += 1;
+          if (ofs >= plen)
+          {
+            /* next octet in next pbuf */
+            p = p->next;
+            if (p == NULL) { return ERR_ARG; }
+            msg_ptr = (u8_t*)p->payload;
+            plen += p->len;
+          }
+          else
+          {
+            /* next octet in same pbuf */
+            msg_ptr++;
+          }
+        }
+        if (sign)
+        {
+          *lsb_ptr &= *msg_ptr;
+        }
+        else
+        {
+          *lsb_ptr |= *msg_ptr;
+        }
+        return ERR_OK;
+      }
+      else
+      {
+        return ERR_ARG;
+      }
+    }
+    p = p->next;
+  }
+  /* p == NULL, ofs >= plen */
+  return ERR_ARG;
+}
+
+/**
+ * Decodes object identifier from incoming message into array of s32_t.
+ *
+ * @param p points to a pbuf holding an ASN1 coded object identifier
+ * @param ofs points to the offset within the pbuf chain of the ASN1 coded object identifier
+ * @param len length of the coded object identifier
+ * @param oid return object identifier struct
+ * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode
+ */
+err_t
+snmp_asn1_dec_oid(struct pbuf *p, u16_t ofs, u16_t len, struct snmp_obj_id *oid)
+{
+  u16_t plen, base;
+  u8_t *msg_ptr;
+  s32_t *oid_ptr;
+
+  plen = 0;
+  while (p != NULL)
+  {
+    base = plen;
+    plen += p->len;
+    if (ofs < plen)
+    {
+      msg_ptr = (u8_t*)p->payload;
+      msg_ptr += ofs - base;
+
+      oid->len = 0;
+      oid_ptr = &oid->id[0];
+      if (len > 0)
+      {
+        /* first compressed octet */
+        if (*msg_ptr == 0x2B)
+        {
+          /* (most) common case 1.3 (iso.org) */
+          *oid_ptr = 1;
+          oid_ptr++;
+          *oid_ptr = 3;
+          oid_ptr++;
+        }
+        else if (*msg_ptr < 40)
+        {
+          *oid_ptr = 0;
+          oid_ptr++;
+          *oid_ptr = *msg_ptr;
+          oid_ptr++;
+        }
+        else if (*msg_ptr < 80)
+        {
+          *oid_ptr = 1;
+          oid_ptr++;
+          *oid_ptr = (*msg_ptr) - 40;
+          oid_ptr++;
+        }
+        else
+        {
+          *oid_ptr = 2;
+          oid_ptr++;
+          *oid_ptr = (*msg_ptr) - 80;
+          oid_ptr++;
+        }
+        oid->len = 2;
+      }
+      else
+      {
+        /* accepting zero length identifiers e.g. for
+           getnext operation. uncommon but valid */
+        return ERR_OK;
+      }
+      len--;
+      if (len > 0)
+      {
+        ofs += 1;
+        if (ofs >= plen)
+        {
+          /* next octet in next pbuf */
+          p = p->next;
+          if (p == NULL) { return ERR_ARG; }
+          msg_ptr = (u8_t*)p->payload;
+          plen += p->len;
+        }
+        else
+        {
+          /* next octet in same pbuf */
+          msg_ptr++;
+        }
+      }
+      while ((len > 0) && (oid->len < LWIP_SNMP_OBJ_ID_LEN))
+      {
+        /* sub-identifier uses multiple octets */
+        if (*msg_ptr & 0x80)
+        {
+          s32_t sub_id = 0;
+
+          while ((*msg_ptr & 0x80) && (len > 1))
+          {
+            len--;
+            sub_id = (sub_id << 7) + (*msg_ptr & ~0x80);
+            ofs += 1;
+            if (ofs >= plen)
+            {
+              /* next octet in next pbuf */
+              p = p->next;
+              if (p == NULL) { return ERR_ARG; }
+              msg_ptr = (u8_t*)p->payload;
+              plen += p->len;
+            }
+            else
+            {
+              /* next octet in same pbuf */
+              msg_ptr++;
+            }
+          }
+          if (!(*msg_ptr & 0x80) && (len > 0))
+          {
+            /* last octet sub-identifier */
+            len--;
+            sub_id = (sub_id << 7) + *msg_ptr;
+            *oid_ptr = sub_id;
+          }
+        }
+        else
+        {
+          /* !(*msg_ptr & 0x80) sub-identifier uses single octet */
+          len--;
+          *oid_ptr = *msg_ptr;
+        }
+        if (len > 0)
+        {
+          /* remaining oid bytes available ... */
+          ofs += 1;
+          if (ofs >= plen)
+          {
+            /* next octet in next pbuf */
+            p = p->next;
+            if (p == NULL) { return ERR_ARG; }
+            msg_ptr = (u8_t*)p->payload;
+            plen += p->len;
+          }
+          else
+          {
+            /* next octet in same pbuf */
+            msg_ptr++;
+          }
+        }
+        oid_ptr++;
+        oid->len++;
+      }
+      if (len == 0)
+      {
+        /* len == 0, end of oid */
+        return ERR_OK;
+      }
+      else
+      {
+        /* len > 0, oid->len == LWIP_SNMP_OBJ_ID_LEN or malformed encoding */
+        return ERR_ARG;
+      }
+
+    }
+    p = p->next;
+  }
+  /* p == NULL, ofs >= plen */
+  return ERR_ARG;
+}
+
+/**
+ * Decodes (copies) raw data (ip-addresses, octet strings, opaque encoding)
+ * from incoming message into array.
+ *
+ * @param p points to a pbuf holding an ASN1 coded raw data
+ * @param ofs points to the offset within the pbuf chain of the ASN1 coded raw data
+ * @param len length of the coded raw data (zero is valid, e.g. empty string!)
+ * @param raw_len length of the raw return value
+ * @param raw return raw bytes
+ * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) decode
+ */
+err_t
+snmp_asn1_dec_raw(struct pbuf *p, u16_t ofs, u16_t len, u16_t raw_len, u8_t *raw)
+{
+  u16_t plen, base;
+  u8_t *msg_ptr;
+
+  if (len > 0)
+  {
+    plen = 0;
+    while (p != NULL)
+    {
+      base = plen;
+      plen += p->len;
+      if (ofs < plen)
+      {
+        msg_ptr = (u8_t*)p->payload;
+        msg_ptr += ofs - base;
+        if (raw_len >= len)
+        {
+          while (len > 1)
+          {
+            /* copy len - 1 octets */
+            len--;
+            *raw = *msg_ptr;
+            raw++;
+            ofs += 1;
+            if (ofs >= plen)
+            {
+              /* next octet in next pbuf */
+              p = p->next;
+              if (p == NULL) { return ERR_ARG; }
+              msg_ptr = (u8_t*)p->payload;
+              plen += p->len;
+            }
+            else
+            {
+              /* next octet in same pbuf */
+              msg_ptr++;
+            }
+          }
+          /* copy last octet */
+          *raw = *msg_ptr;
+          return ERR_OK;
+        }
+        else
+        {
+          /* raw_len < len, not enough dst space */
+          return ERR_ARG;
+        }
+      }
+      p = p->next;
+    }
+    /* p == NULL, ofs >= plen */
+    return ERR_ARG;
+  }
+  else
+  {
+    /* len == 0, empty string */
+    return ERR_OK;
+  }
+}
+
+#endif /* LWIP_SNMP */
diff --git a/core/lwip/src/core/snmp/asn1_enc.c b/core/lwip/src/core/snmp/asn1_enc.c
new file mode 100644
index 00000000..64dfc5f6
--- /dev/null
+++ b/core/lwip/src/core/snmp/asn1_enc.c
@@ -0,0 +1,611 @@
+/**
+ * @file
+ * Abstract Syntax Notation One (ISO 8824, 8825) encoding
+ *
+ * @todo not optimised (yet), favor correctness over speed, favor speed over size
+ */
+
+/*
+ * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * Author: Christiaan Simons <christiaan.simons@axon.tv>
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/snmp_asn1.h"
+
+/**
+ * Returns octet count for length.
+ *
+ * @param length
+ * @param octets_needed points to the return value
+ */
+void
+snmp_asn1_enc_length_cnt(u16_t length, u8_t *octets_needed)
+{
+  if (length < 0x80U)
+  {
+    *octets_needed = 1;
+  }
+  else if (length < 0x100U)
+  {
+    *octets_needed = 2;
+  }
+  else
+  {
+    *octets_needed = 3;
+  }
+}
+
+/**
+ * Returns octet count for an u32_t.
+ *
+ * @param value
+ * @param octets_needed points to the return value
+ *
+ * @note ASN coded integers are _always_ signed. E.g. +0xFFFF is coded
+ * as 0x00,0xFF,0xFF. Note the leading sign octet. A positive value
+ * of 0xFFFFFFFF is preceded with 0x00 and the length is 5 octets!!
+ */
+void
+snmp_asn1_enc_u32t_cnt(u32_t value, u16_t *octets_needed)
+{
+  if (value < 0x80UL)
+  {
+    *octets_needed = 1;
+  }
+  else if (value < 0x8000UL)
+  {
+    *octets_needed = 2;
+  }
+  else if (value < 0x800000UL)
+  {
+    *octets_needed = 3;
+  }
+  else if (value < 0x80000000UL)
+  {
+    *octets_needed = 4;
+  }
+  else
+  {
+    *octets_needed = 5;
+  }
+}
+
+/**
+ * Returns octet count for an s32_t.
+ *
+ * @param value
+ * @param octets_needed points to the return value
+ *
+ * @note ASN coded integers are _always_ signed.
+ */
+void
+snmp_asn1_enc_s32t_cnt(s32_t value, u16_t *octets_needed)
+{
+  if (value < 0)
+  {
+    value = ~value;
+  }
+  if (value < 0x80L)
+  {
+    *octets_needed = 1;
+  }
+  else if (value < 0x8000L)
+  {
+    *octets_needed = 2;
+  }
+  else if (value < 0x800000L)
+  {
+    *octets_needed = 3;
+  }
+  else
+  {
+    *octets_needed = 4;
+  }
+}
+
+/**
+ * Returns octet count for an object identifier.
+ *
+ * @param ident_len object identifier array length
+ * @param ident points to object identifier array
+ * @param octets_needed points to the return value
+ */
+void
+snmp_asn1_enc_oid_cnt(u8_t ident_len, s32_t *ident, u16_t *octets_needed)
+{
+  s32_t sub_id;
+  u8_t cnt;
+
+  cnt = 0;
+  if (ident_len > 1)
+  {
+    /* compressed prefix in one octet */
+    cnt++;
+    ident_len -= 2;
+    ident += 2;
+  }
+  while(ident_len > 0)
+  {
+    ident_len--;
+    sub_id = *ident;
+
+    sub_id >>= 7;
+    cnt++;
+    while(sub_id > 0)
+    {
+      sub_id >>= 7;
+      cnt++;
+    }
+    ident++;
+  }
+  *octets_needed = cnt;
+}
+
+/**
+ * Encodes ASN type field into a pbuf chained ASN1 msg.
+ *
+ * @param p points to output pbuf to encode value into
+ * @param ofs points to the offset within the pbuf chain
+ * @param type input ASN1 type
+ * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) encode
+ */
+err_t
+snmp_asn1_enc_type(struct pbuf *p, u16_t ofs, u8_t type)
+{
+  u16_t plen, base;
+  u8_t *msg_ptr;
+
+  plen = 0;
+  while (p != NULL)
+  {
+    base = plen;
+    plen += p->len;
+    if (ofs < plen)
+    {
+      msg_ptr = (u8_t*)p->payload;
+      msg_ptr += ofs - base;
+      *msg_ptr = type;
+      return ERR_OK;
+    }
+    p = p->next;
+  }
+  /* p == NULL, ofs >= plen */
+  return ERR_ARG;
+}
+
+/**
+ * Encodes host order length field into a pbuf chained ASN1 msg.
+ *
+ * @param p points to output pbuf to encode length into
+ * @param ofs points to the offset within the pbuf chain
+ * @param length is the host order length to be encoded
+ * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) encode
+ */
+err_t
+snmp_asn1_enc_length(struct pbuf *p, u16_t ofs, u16_t length)
+{
+  u16_t plen, base;
+  u8_t *msg_ptr;
+
+  plen = 0;
+  while (p != NULL)
+  {
+    base = plen;
+    plen += p->len;
+    if (ofs < plen)
+    {
+      msg_ptr = (u8_t*)p->payload;
+      msg_ptr += ofs - base;
+
+      if (length < 0x80)
+      {
+        *msg_ptr = (u8_t)length;
+        return ERR_OK;
+      }
+      else if (length < 0x100)
+      {
+        *msg_ptr = 0x81;
+        ofs += 1;
+        if (ofs >= plen)
+        {
+          /* next octet in next pbuf */
+          p = p->next;
+          if (p == NULL) { return ERR_ARG; }
+          msg_ptr = (u8_t*)p->payload;
+        }
+        else
+        {
+          /* next octet in same pbuf */
+          msg_ptr++;
+        }
+        *msg_ptr = (u8_t)length;
+        return ERR_OK;
+      }
+      else
+      {
+        u8_t i;
+
+        /* length >= 0x100 && length <= 0xFFFF */
+        *msg_ptr = 0x82;
+        i = 2;
+        while (i > 0)
+        {
+          i--;
+          ofs += 1;
+          if (ofs >= plen)
+          {
+            /* next octet in next pbuf */
+            p = p->next;
+            if (p == NULL) { return ERR_ARG; }
+            msg_ptr = (u8_t*)p->payload;
+            plen += p->len;
+          }
+          else
+          {
+            /* next octet in same pbuf */
+            msg_ptr++;
+          }
+          if (i == 0)
+          {
+            /* least significant length octet */
+            *msg_ptr = (u8_t)length;
+          }
+          else
+          {
+            /* most significant length octet */
+            *msg_ptr = (u8_t)(length >> 8);
+          }
+        }
+        return ERR_OK;
+      }
+    }
+    p = p->next;
+  }
+  /* p == NULL, ofs >= plen */
+  return ERR_ARG;
+}
+
+/**
+ * Encodes u32_t (counter, gauge, timeticks) into a pbuf chained ASN1 msg.
+ *
+ * @param p points to output pbuf to encode value into
+ * @param ofs points to the offset within the pbuf chain
+ * @param octets_needed encoding length (from snmp_asn1_enc_u32t_cnt())
+ * @param value is the host order u32_t value to be encoded
+ * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) encode
+ *
+ * @see snmp_asn1_enc_u32t_cnt()
+ */
+err_t
+snmp_asn1_enc_u32t(struct pbuf *p, u16_t ofs, u16_t octets_needed, u32_t value)
+{
+  u16_t plen, base;
+  u8_t *msg_ptr;
+
+  plen = 0;
+  while (p != NULL)
+  {
+    base = plen;
+    plen += p->len;
+    if (ofs < plen)
+    {
+      msg_ptr = (u8_t*)p->payload;
+      msg_ptr += ofs - base;
+
+      if (octets_needed == 5)
+      {
+        /* not enough bits in 'value' add leading 0x00 */
+        octets_needed--;
+        *msg_ptr = 0x00;
+        ofs += 1;
+        if (ofs >= plen)
+        {
+          /* next octet in next pbuf */
+          p = p->next;
+          if (p == NULL) { return ERR_ARG; }
+          msg_ptr = (u8_t*)p->payload;
+          plen += p->len;
+        }
+        else
+        {
+          /* next octet in same pbuf */
+          msg_ptr++;
+        }
+      }
+      while (octets_needed > 1)
+      {
+        octets_needed--;
+        *msg_ptr = (u8_t)(value >> (octets_needed << 3));
+        ofs += 1;
+        if (ofs >= plen)
+        {
+          /* next octet in next pbuf */
+          p = p->next;
+          if (p == NULL) { return ERR_ARG; }
+          msg_ptr = (u8_t*)p->payload;
+          plen += p->len;
+        }
+        else
+        {
+          /* next octet in same pbuf */
+          msg_ptr++;
+        }
+      }
+      /* (only) one least significant octet */
+      *msg_ptr = (u8_t)value;
+      return ERR_OK;
+    }
+    p = p->next;
+  }
+  /* p == NULL, ofs >= plen */
+  return ERR_ARG;
+}
+
+/**
+ * Encodes s32_t integer into a pbuf chained ASN1 msg.
+ *
+ * @param p points to output pbuf to encode value into
+ * @param ofs points to the offset within the pbuf chain
+ * @param octets_needed encoding length (from snmp_asn1_enc_s32t_cnt())
+ * @param value is the host order s32_t value to be encoded
+ * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) encode
+ *
+ * @see snmp_asn1_enc_s32t_cnt()
+ */
+err_t
+snmp_asn1_enc_s32t(struct pbuf *p, u16_t ofs, u16_t octets_needed, s32_t value)
+{
+  u16_t plen, base;
+  u8_t *msg_ptr;
+
+  plen = 0;
+  while (p != NULL)
+  {
+    base = plen;
+    plen += p->len;
+    if (ofs < plen)
+    {
+      msg_ptr = (u8_t*)p->payload;
+      msg_ptr += ofs - base;
+
+      while (octets_needed > 1)
+      {
+        octets_needed--;
+        *msg_ptr = (u8_t)(value >> (octets_needed << 3));
+        ofs += 1;
+        if (ofs >= plen)
+        {
+          /* next octet in next pbuf */
+          p = p->next;
+          if (p == NULL) { return ERR_ARG; }
+          msg_ptr = (u8_t*)p->payload;
+          plen += p->len;
+        }
+        else
+        {
+          /* next octet in same pbuf */
+          msg_ptr++;
+        }
+      }
+      /* (only) one least significant octet */
+      *msg_ptr = (u8_t)value;
+      return ERR_OK;
+    }
+    p = p->next;
+  }
+  /* p == NULL, ofs >= plen */
+  return ERR_ARG;
+}
+
+/**
+ * Encodes object identifier into a pbuf chained ASN1 msg.
+ *
+ * @param p points to output pbuf to encode oid into
+ * @param ofs points to the offset within the pbuf chain
+ * @param ident_len object identifier array length
+ * @param ident points to object identifier array
+ * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) encode
+ */
+err_t
+snmp_asn1_enc_oid(struct pbuf *p, u16_t ofs, u8_t ident_len, s32_t *ident)
+{
+  u16_t plen, base;
+  u8_t *msg_ptr;
+
+  plen = 0;
+  while (p != NULL)
+  {
+    base = plen;
+    plen += p->len;
+    if (ofs < plen)
+    {
+      msg_ptr = (u8_t*)p->payload;
+      msg_ptr += ofs - base;
+
+      if (ident_len > 1)
+      {
+        if ((ident[0] == 1) && (ident[1] == 3))
+        {
+          /* compressed (most common) prefix .iso.org */
+          *msg_ptr = 0x2b;
+        }
+        else
+        {
+          /* calculate prefix */
+          *msg_ptr = (u8_t)((ident[0] * 40) + ident[1]);
+        }
+        ofs += 1;
+        if (ofs >= plen)
+        {
+          /* next octet in next pbuf */
+          p = p->next;
+          if (p == NULL) { return ERR_ARG; }
+          msg_ptr = (u8_t*)p->payload;
+          plen += p->len;
+        }
+        else
+        {
+          /* next octet in same pbuf */
+          msg_ptr++;
+        }
+        ident_len -= 2;
+        ident += 2;
+      }
+      else
+      {
+/* @bug:  allow empty varbinds for symmetry (we must decode them for getnext), allow partial compression??  */
+        /* ident_len <= 1, at least we need zeroDotZero (0.0) (ident_len == 2) */
+        return ERR_ARG;
+      }
+      while (ident_len > 0)
+      {
+        s32_t sub_id;
+        u8_t shift, tail;
+
+        ident_len--;
+        sub_id = *ident;
+        tail = 0;
+        shift = 28;
+        while(shift > 0)
+        {
+          u8_t code;
+
+          code = (u8_t)(sub_id >> shift);
+          if ((code != 0) || (tail != 0))
+          {
+            tail = 1;
+            *msg_ptr = code | 0x80;
+            ofs += 1;
+            if (ofs >= plen)
+            {
+              /* next octet in next pbuf */
+              p = p->next;
+              if (p == NULL) { return ERR_ARG; }
+              msg_ptr = (u8_t*)p->payload;
+              plen += p->len;
+            }
+            else
+            {
+              /* next octet in same pbuf */
+              msg_ptr++;
+            }
+          }
+          shift -= 7;
+        }
+        *msg_ptr = (u8_t)sub_id & 0x7F;
+        if (ident_len > 0)
+        {
+          ofs += 1;
+          if (ofs >= plen)
+          {
+            /* next octet in next pbuf */
+            p = p->next;
+            if (p == NULL) { return ERR_ARG; }
+            msg_ptr = (u8_t*)p->payload;
+            plen += p->len;
+          }
+          else
+          {
+            /* next octet in same pbuf */
+            msg_ptr++;
+          }
+        }
+        /* proceed to next sub-identifier */
+        ident++;
+      }
+      return ERR_OK;
+    }
+    p = p->next;
+  }
+  /* p == NULL, ofs >= plen */
+  return ERR_ARG;
+}
+
+/**
+ * Encodes raw data (octet string, opaque) into a pbuf chained ASN1 msg.
+ *
+ * @param p points to output pbuf to encode raw data into
+ * @param ofs points to the offset within the pbuf chain
+ * @param raw_len raw data length
+ * @param raw points raw data
+ * @return ERR_OK if successfull, ERR_ARG if we can't (or won't) encode
+ */
+err_t
+snmp_asn1_enc_raw(struct pbuf *p, u16_t ofs, u16_t raw_len, u8_t *raw)
+{
+  u16_t plen, base;
+  u8_t *msg_ptr;
+
+  plen = 0;
+  while (p != NULL)
+  {
+    base = plen;
+    plen += p->len;
+    if (ofs < plen)
+    {
+      msg_ptr = (u8_t*)p->payload;
+      msg_ptr += ofs - base;
+
+      while (raw_len > 1)
+      {
+        /* copy raw_len - 1 octets */
+        raw_len--;
+        *msg_ptr = *raw;
+        raw++;
+        ofs += 1;
+        if (ofs >= plen)
+        {
+          /* next octet in next pbuf */
+          p = p->next;
+          if (p == NULL) { return ERR_ARG; }
+          msg_ptr = (u8_t*)p->payload;
+          plen += p->len;
+        }
+        else
+        {
+          /* next octet in same pbuf */
+          msg_ptr++;
+        }
+      }
+      if (raw_len > 0)
+      {
+        /* copy last or single octet */
+        *msg_ptr = *raw;
+      }
+      return ERR_OK;
+    }
+    p = p->next;
+  }
+  /* p == NULL, ofs >= plen */
+  return ERR_ARG;
+}
+
+#endif /* LWIP_SNMP */
diff --git a/core/lwip/src/core/snmp/mib2.c b/core/lwip/src/core/snmp/mib2.c
new file mode 100644
index 00000000..29decd30
--- /dev/null
+++ b/core/lwip/src/core/snmp/mib2.c
@@ -0,0 +1,4146 @@
+/**
+ * @file
+ * Management Information Base II (RFC1213) objects and functions.
+ *
+ * @note the object identifiers for this MIB-2 and private MIB tree
+ * must be kept in sorted ascending order. This to ensure correct getnext operation.
+ */
+
+/*
+ * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * Author: Christiaan Simons <christiaan.simons@axon.tv>
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/snmp.h"
+#include "lwip/netif.h"
+#include "lwip/ip.h"
+#include "lwip/ip_frag.h"
+#include "lwip/mem.h"
+#include "lwip/tcp_impl.h"
+#include "lwip/udp.h"
+#include "lwip/snmp_asn1.h"
+#include "lwip/snmp_structs.h"
+#include "lwip/sys.h"
+#include "netif/etharp.h"
+
+/**
+ * IANA assigned enterprise ID for lwIP is 26381
+ * @see http://www.iana.org/assignments/enterprise-numbers
+ *
+ * @note this enterprise ID is assigned to the lwIP project,
+ * all object identifiers living under this ID are assigned
+ * by the lwIP maintainers (contact Christiaan Simons)!
+ * @note don't change this define, use snmp_set_sysobjid()
+ *
+ * If you need to create your own private MIB you'll need
+ * to apply for your own enterprise ID with IANA:
+ * http://www.iana.org/numbers.html
+ */
+#define SNMP_ENTERPRISE_ID 26381
+#define SNMP_SYSOBJID_LEN 7
+#define SNMP_SYSOBJID {1, 3, 6, 1, 4, 1, SNMP_ENTERPRISE_ID}
+
+#ifndef SNMP_SYSSERVICES
+#define SNMP_SYSSERVICES ((1 << 6) | (1 << 3) | ((IP_FORWARD) << 2))
+#endif
+
+#ifndef SNMP_GET_SYSUPTIME
+#define SNMP_GET_SYSUPTIME(sysuptime)
+#endif
+
+static void system_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od);
+static void system_get_value(struct obj_def *od, u16_t len, void *value);
+static u8_t system_set_test(struct obj_def *od, u16_t len, void *value);
+static void system_set_value(struct obj_def *od, u16_t len, void *value);
+static void interfaces_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od);
+static void interfaces_get_value(struct obj_def *od, u16_t len, void *value);
+static void ifentry_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od);
+static void ifentry_get_value(struct obj_def *od, u16_t len, void *value);
+#if !SNMP_SAFE_REQUESTS
+static u8_t ifentry_set_test (struct obj_def *od, u16_t len, void *value);
+static void ifentry_set_value (struct obj_def *od, u16_t len, void *value);
+#endif /* SNMP_SAFE_REQUESTS */
+static void atentry_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od);
+static void atentry_get_value(struct obj_def *od, u16_t len, void *value);
+static void ip_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od);
+static void ip_get_value(struct obj_def *od, u16_t len, void *value);
+static u8_t ip_set_test(struct obj_def *od, u16_t len, void *value);
+static void ip_addrentry_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od);
+static void ip_addrentry_get_value(struct obj_def *od, u16_t len, void *value);
+static void ip_rteentry_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od);
+static void ip_rteentry_get_value(struct obj_def *od, u16_t len, void *value);
+static void ip_ntomentry_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od);
+static void ip_ntomentry_get_value(struct obj_def *od, u16_t len, void *value);
+static void icmp_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od);
+static void icmp_get_value(struct obj_def *od, u16_t len, void *value);
+#if LWIP_TCP
+static void tcp_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od);
+static void tcp_get_value(struct obj_def *od, u16_t len, void *value);
+#ifdef THIS_SEEMS_UNUSED
+static void tcpconnentry_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od);
+static void tcpconnentry_get_value(struct obj_def *od, u16_t len, void *value);
+#endif
+#endif
+static void udp_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od);
+static void udp_get_value(struct obj_def *od, u16_t len, void *value);
+static void udpentry_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od);
+static void udpentry_get_value(struct obj_def *od, u16_t len, void *value);
+static void snmp_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od);
+static void snmp_get_value(struct obj_def *od, u16_t len, void *value);
+static u8_t snmp_set_test(struct obj_def *od, u16_t len, void *value);
+static void snmp_set_value(struct obj_def *od, u16_t len, void *value);
+
+
+/* snmp .1.3.6.1.2.1.11 */
+const mib_scalar_node snmp_scalar = {
+  &snmp_get_object_def,
+  &snmp_get_value,
+  &snmp_set_test,
+  &snmp_set_value,
+  MIB_NODE_SC,
+  0
+};
+const s32_t snmp_ids[28] = {
+  1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+  17, 18, 19, 20, 21, 22, 24, 25, 26, 27, 28, 29, 30
+};
+struct mib_node* const snmp_nodes[28] = {
+  (struct mib_node*)&snmp_scalar, (struct mib_node*)&snmp_scalar,
+  (struct mib_node*)&snmp_scalar, (struct mib_node*)&snmp_scalar,
+  (struct mib_node*)&snmp_scalar, (struct mib_node*)&snmp_scalar,
+  (struct mib_node*)&snmp_scalar, (struct mib_node*)&snmp_scalar,
+  (struct mib_node*)&snmp_scalar, (struct mib_node*)&snmp_scalar,
+  (struct mib_node*)&snmp_scalar, (struct mib_node*)&snmp_scalar,
+  (struct mib_node*)&snmp_scalar, (struct mib_node*)&snmp_scalar,
+  (struct mib_node*)&snmp_scalar, (struct mib_node*)&snmp_scalar,
+  (struct mib_node*)&snmp_scalar, (struct mib_node*)&snmp_scalar,
+  (struct mib_node*)&snmp_scalar, (struct mib_node*)&snmp_scalar,
+  (struct mib_node*)&snmp_scalar, (struct mib_node*)&snmp_scalar,
+  (struct mib_node*)&snmp_scalar, (struct mib_node*)&snmp_scalar,
+  (struct mib_node*)&snmp_scalar, (struct mib_node*)&snmp_scalar,
+  (struct mib_node*)&snmp_scalar, (struct mib_node*)&snmp_scalar
+};
+const struct mib_array_node snmp = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  28,
+  snmp_ids,
+  snmp_nodes
+};
+
+/* dot3 and EtherLike MIB not planned. (transmission .1.3.6.1.2.1.10) */
+/* historical (some say hysterical). (cmot .1.3.6.1.2.1.9) */
+/* lwIP has no EGP, thus may not implement it. (egp .1.3.6.1.2.1.8) */
+
+/* udp .1.3.6.1.2.1.7 */
+/** index root node for udpTable */
+struct mib_list_rootnode udp_root = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_LR,
+  0,
+  NULL,
+  NULL,
+  0
+};
+const s32_t udpentry_ids[2] = { 1, 2 };
+struct mib_node* const udpentry_nodes[2] = {
+  (struct mib_node*)&udp_root, (struct mib_node*)&udp_root,
+};
+const struct mib_array_node udpentry = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  2,
+  udpentry_ids,
+  udpentry_nodes
+};
+
+s32_t udptable_id = 1;
+struct mib_node* udptable_node = (struct mib_node*)&udpentry;
+struct mib_ram_array_node udptable = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_RA,
+  0,
+  &udptable_id,
+  &udptable_node
+};
+
+const mib_scalar_node udp_scalar = {
+  &udp_get_object_def,
+  &udp_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_SC,
+  0
+};
+const s32_t udp_ids[5] = { 1, 2, 3, 4, 5 };
+struct mib_node* const udp_nodes[5] = {
+  (struct mib_node*)&udp_scalar, (struct mib_node*)&udp_scalar,
+  (struct mib_node*)&udp_scalar, (struct mib_node*)&udp_scalar,
+  (struct mib_node*)&udptable
+};
+const struct mib_array_node udp = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  5,
+  udp_ids,
+  udp_nodes
+};
+
+/* tcp .1.3.6.1.2.1.6 */
+#if LWIP_TCP
+/* only if the TCP protocol is available may implement this group */
+/** index root node for tcpConnTable */
+struct mib_list_rootnode tcpconntree_root = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_LR,
+  0,
+  NULL,
+  NULL,
+  0
+};
+const s32_t tcpconnentry_ids[5] = { 1, 2, 3, 4, 5 };
+struct mib_node* const tcpconnentry_nodes[5] = {
+  (struct mib_node*)&tcpconntree_root, (struct mib_node*)&tcpconntree_root,
+  (struct mib_node*)&tcpconntree_root, (struct mib_node*)&tcpconntree_root,
+  (struct mib_node*)&tcpconntree_root
+};
+const struct mib_array_node tcpconnentry = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  5,
+  tcpconnentry_ids,
+  tcpconnentry_nodes
+};
+
+s32_t tcpconntable_id = 1;
+struct mib_node* tcpconntable_node = (struct mib_node*)&tcpconnentry;
+struct mib_ram_array_node tcpconntable = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_RA,
+/** @todo update maxlength when inserting / deleting from table
+   0 when table is empty, 1 when more than one entry */
+  0,
+  &tcpconntable_id,
+  &tcpconntable_node
+};
+
+const mib_scalar_node tcp_scalar = {
+  &tcp_get_object_def,
+  &tcp_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_SC,
+  0
+};
+const s32_t tcp_ids[15] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 };
+struct mib_node* const tcp_nodes[15] = {
+  (struct mib_node*)&tcp_scalar, (struct mib_node*)&tcp_scalar,
+  (struct mib_node*)&tcp_scalar, (struct mib_node*)&tcp_scalar,
+  (struct mib_node*)&tcp_scalar, (struct mib_node*)&tcp_scalar,
+  (struct mib_node*)&tcp_scalar, (struct mib_node*)&tcp_scalar,
+  (struct mib_node*)&tcp_scalar, (struct mib_node*)&tcp_scalar,
+  (struct mib_node*)&tcp_scalar, (struct mib_node*)&tcp_scalar,
+  (struct mib_node*)&tcpconntable, (struct mib_node*)&tcp_scalar,
+  (struct mib_node*)&tcp_scalar
+};
+const struct mib_array_node tcp = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  15,
+  tcp_ids,
+  tcp_nodes
+};
+#endif
+
+/* icmp .1.3.6.1.2.1.5 */
+const mib_scalar_node icmp_scalar = {
+  &icmp_get_object_def,
+  &icmp_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_SC,
+  0
+};
+const s32_t icmp_ids[26] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26 };
+struct mib_node* const icmp_nodes[26] = {
+  (struct mib_node*)&icmp_scalar, (struct mib_node*)&icmp_scalar,
+  (struct mib_node*)&icmp_scalar, (struct mib_node*)&icmp_scalar,
+  (struct mib_node*)&icmp_scalar, (struct mib_node*)&icmp_scalar,
+  (struct mib_node*)&icmp_scalar, (struct mib_node*)&icmp_scalar,
+  (struct mib_node*)&icmp_scalar, (struct mib_node*)&icmp_scalar,
+  (struct mib_node*)&icmp_scalar, (struct mib_node*)&icmp_scalar,
+  (struct mib_node*)&icmp_scalar, (struct mib_node*)&icmp_scalar,
+  (struct mib_node*)&icmp_scalar, (struct mib_node*)&icmp_scalar,
+  (struct mib_node*)&icmp_scalar, (struct mib_node*)&icmp_scalar,
+  (struct mib_node*)&icmp_scalar, (struct mib_node*)&icmp_scalar,
+  (struct mib_node*)&icmp_scalar, (struct mib_node*)&icmp_scalar,
+  (struct mib_node*)&icmp_scalar, (struct mib_node*)&icmp_scalar,
+  (struct mib_node*)&icmp_scalar, (struct mib_node*)&icmp_scalar
+};
+const struct mib_array_node icmp = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  26,
+  icmp_ids,
+  icmp_nodes
+};
+
+/** index root node for ipNetToMediaTable */
+struct mib_list_rootnode ipntomtree_root = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_LR,
+  0,
+  NULL,
+  NULL,
+  0
+};
+const s32_t ipntomentry_ids[4] = { 1, 2, 3, 4 };
+struct mib_node* const ipntomentry_nodes[4] = {
+  (struct mib_node*)&ipntomtree_root, (struct mib_node*)&ipntomtree_root,
+  (struct mib_node*)&ipntomtree_root, (struct mib_node*)&ipntomtree_root
+};
+const struct mib_array_node ipntomentry = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  4,
+  ipntomentry_ids,
+  ipntomentry_nodes
+};
+
+s32_t ipntomtable_id = 1;
+struct mib_node* ipntomtable_node = (struct mib_node*)&ipntomentry;
+struct mib_ram_array_node ipntomtable = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_RA,
+  0,
+  &ipntomtable_id,
+  &ipntomtable_node
+};
+
+/** index root node for ipRouteTable */
+struct mib_list_rootnode iprtetree_root = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_LR,
+  0,
+  NULL,
+  NULL,
+  0
+};
+const s32_t iprteentry_ids[13] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 };
+struct mib_node* const iprteentry_nodes[13] = {
+  (struct mib_node*)&iprtetree_root, (struct mib_node*)&iprtetree_root,
+  (struct mib_node*)&iprtetree_root, (struct mib_node*)&iprtetree_root,
+  (struct mib_node*)&iprtetree_root, (struct mib_node*)&iprtetree_root,
+  (struct mib_node*)&iprtetree_root, (struct mib_node*)&iprtetree_root,
+  (struct mib_node*)&iprtetree_root, (struct mib_node*)&iprtetree_root,
+  (struct mib_node*)&iprtetree_root, (struct mib_node*)&iprtetree_root,
+  (struct mib_node*)&iprtetree_root
+};
+const struct mib_array_node iprteentry = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  13,
+  iprteentry_ids,
+  iprteentry_nodes
+};
+
+s32_t iprtetable_id = 1;
+struct mib_node* iprtetable_node = (struct mib_node*)&iprteentry;
+struct mib_ram_array_node iprtetable = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_RA,
+  0,
+  &iprtetable_id,
+  &iprtetable_node
+};
+
+/** index root node for ipAddrTable */
+struct mib_list_rootnode ipaddrtree_root = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_LR,
+  0,
+  NULL,
+  NULL,
+  0
+};
+const s32_t ipaddrentry_ids[5] = { 1, 2, 3, 4, 5 };
+struct mib_node* const ipaddrentry_nodes[5] = {
+  (struct mib_node*)&ipaddrtree_root,
+  (struct mib_node*)&ipaddrtree_root,
+  (struct mib_node*)&ipaddrtree_root,
+  (struct mib_node*)&ipaddrtree_root,
+  (struct mib_node*)&ipaddrtree_root
+};
+const struct mib_array_node ipaddrentry = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  5,
+  ipaddrentry_ids,
+  ipaddrentry_nodes
+};
+
+s32_t ipaddrtable_id = 1;
+struct mib_node* ipaddrtable_node = (struct mib_node*)&ipaddrentry;
+struct mib_ram_array_node ipaddrtable = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_RA,
+  0,
+  &ipaddrtable_id,
+  &ipaddrtable_node
+};
+
+/* ip .1.3.6.1.2.1.4 */
+const mib_scalar_node ip_scalar = {
+  &ip_get_object_def,
+  &ip_get_value,
+  &ip_set_test,
+  &noleafs_set_value,
+  MIB_NODE_SC,
+  0
+};
+const s32_t ip_ids[23] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 };
+struct mib_node* const ip_nodes[23] = {
+  (struct mib_node*)&ip_scalar, (struct mib_node*)&ip_scalar,
+  (struct mib_node*)&ip_scalar, (struct mib_node*)&ip_scalar,
+  (struct mib_node*)&ip_scalar, (struct mib_node*)&ip_scalar,
+  (struct mib_node*)&ip_scalar, (struct mib_node*)&ip_scalar,
+  (struct mib_node*)&ip_scalar, (struct mib_node*)&ip_scalar,
+  (struct mib_node*)&ip_scalar, (struct mib_node*)&ip_scalar,
+  (struct mib_node*)&ip_scalar, (struct mib_node*)&ip_scalar,
+  (struct mib_node*)&ip_scalar, (struct mib_node*)&ip_scalar,
+  (struct mib_node*)&ip_scalar, (struct mib_node*)&ip_scalar,
+  (struct mib_node*)&ip_scalar, (struct mib_node*)&ipaddrtable,
+  (struct mib_node*)&iprtetable, (struct mib_node*)&ipntomtable,
+  (struct mib_node*)&ip_scalar
+};
+const struct mib_array_node mib2_ip = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  23,
+  ip_ids,
+  ip_nodes
+};
+
+/** index root node for atTable */
+struct mib_list_rootnode arptree_root = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_LR,
+  0,
+  NULL,
+  NULL,
+  0
+};
+const s32_t atentry_ids[3] = { 1, 2, 3 };
+struct mib_node* const atentry_nodes[3] = {
+  (struct mib_node*)&arptree_root,
+  (struct mib_node*)&arptree_root,
+  (struct mib_node*)&arptree_root
+};
+const struct mib_array_node atentry = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  3,
+  atentry_ids,
+  atentry_nodes
+};
+
+const s32_t attable_id = 1;
+struct mib_node* const attable_node = (struct mib_node*)&atentry;
+const struct mib_array_node attable = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  1,
+  &attable_id,
+  &attable_node
+};
+
+/* at .1.3.6.1.2.1.3 */
+s32_t at_id = 1;
+struct mib_node* mib2_at_node = (struct mib_node*)&attable;
+struct mib_ram_array_node at = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_RA,
+  0,
+  &at_id,
+  &mib2_at_node
+};
+
+/** index root node for ifTable */
+struct mib_list_rootnode iflist_root = {
+  &ifentry_get_object_def,
+  &ifentry_get_value,
+#if SNMP_SAFE_REQUESTS
+  &noleafs_set_test,
+  &noleafs_set_value,
+#else /* SNMP_SAFE_REQUESTS */
+  &ifentry_set_test,
+  &ifentry_set_value,
+#endif /* SNMP_SAFE_REQUESTS */
+  MIB_NODE_LR,
+  0,
+  NULL,
+  NULL,
+  0
+};
+const s32_t ifentry_ids[22] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 };
+struct mib_node* const ifentry_nodes[22] = {
+  (struct mib_node*)&iflist_root, (struct mib_node*)&iflist_root,
+  (struct mib_node*)&iflist_root, (struct mib_node*)&iflist_root,
+  (struct mib_node*)&iflist_root, (struct mib_node*)&iflist_root,
+  (struct mib_node*)&iflist_root, (struct mib_node*)&iflist_root,
+  (struct mib_node*)&iflist_root, (struct mib_node*)&iflist_root,
+  (struct mib_node*)&iflist_root, (struct mib_node*)&iflist_root,
+  (struct mib_node*)&iflist_root, (struct mib_node*)&iflist_root,
+  (struct mib_node*)&iflist_root, (struct mib_node*)&iflist_root,
+  (struct mib_node*)&iflist_root, (struct mib_node*)&iflist_root,
+  (struct mib_node*)&iflist_root, (struct mib_node*)&iflist_root,
+  (struct mib_node*)&iflist_root, (struct mib_node*)&iflist_root
+};
+const struct mib_array_node ifentry = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  22,
+  ifentry_ids,
+  ifentry_nodes
+};
+
+s32_t iftable_id = 1;
+struct mib_node* iftable_node = (struct mib_node*)&ifentry;
+struct mib_ram_array_node iftable = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_RA,
+  0,
+  &iftable_id,
+  &iftable_node
+};
+
+/* interfaces .1.3.6.1.2.1.2 */
+const mib_scalar_node interfaces_scalar = {
+  &interfaces_get_object_def,
+  &interfaces_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_SC,
+  0
+};
+const s32_t interfaces_ids[2] = { 1, 2 };
+struct mib_node* const interfaces_nodes[2] = {
+  (struct mib_node*)&interfaces_scalar, (struct mib_node*)&iftable
+};
+const struct mib_array_node interfaces = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  2,
+  interfaces_ids,
+  interfaces_nodes
+};
+
+
+/*             0 1 2 3 4 5 6 */
+/* system .1.3.6.1.2.1.1 */
+const mib_scalar_node sys_tem_scalar = {
+  &system_get_object_def,
+  &system_get_value,
+  &system_set_test,
+  &system_set_value,
+  MIB_NODE_SC,
+  0
+};
+const s32_t sys_tem_ids[7] = { 1, 2, 3, 4, 5, 6, 7 };
+struct mib_node* const sys_tem_nodes[7] = {
+  (struct mib_node*)&sys_tem_scalar, (struct mib_node*)&sys_tem_scalar,
+  (struct mib_node*)&sys_tem_scalar, (struct mib_node*)&sys_tem_scalar,
+  (struct mib_node*)&sys_tem_scalar, (struct mib_node*)&sys_tem_scalar,
+  (struct mib_node*)&sys_tem_scalar
+};
+/* work around name issue with 'sys_tem', some compiler(s?) seem to reserve 'system' */
+const struct mib_array_node sys_tem = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  7,
+  sys_tem_ids,
+  sys_tem_nodes
+};
+
+/* mib-2 .1.3.6.1.2.1 */
+#if LWIP_TCP
+#define MIB2_GROUPS 8
+#else
+#define MIB2_GROUPS 7
+#endif
+const s32_t mib2_ids[MIB2_GROUPS] =
+{
+  1,
+  2,
+  3,
+  4,
+  5,
+#if LWIP_TCP
+  6,
+#endif
+  7,
+  11
+};
+struct mib_node* const mib2_nodes[MIB2_GROUPS] = {
+  (struct mib_node*)&sys_tem,
+  (struct mib_node*)&interfaces,
+  (struct mib_node*)&at,
+  (struct mib_node*)&mib2_ip,
+  (struct mib_node*)&icmp,
+#if LWIP_TCP
+  (struct mib_node*)&tcp,
+#endif
+  (struct mib_node*)&udp,
+  (struct mib_node*)&snmp
+};
+
+const struct mib_array_node mib2 = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  MIB2_GROUPS,
+  mib2_ids,
+  mib2_nodes
+};
+
+/* mgmt .1.3.6.1.2 */
+const s32_t mgmt_ids[1] = { 1 };
+struct mib_node* const mgmt_nodes[1] = { (struct mib_node*)&mib2 };
+const struct mib_array_node mgmt = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  1,
+  mgmt_ids,
+  mgmt_nodes
+};
+
+/* internet .1.3.6.1 */
+#if SNMP_PRIVATE_MIB
+/* When using a private MIB, you have to create a file 'private_mib.h' that contains
+ * a 'struct mib_array_node mib_private' which contains your MIB. */
+s32_t internet_ids[2] = { 2, 4 };
+struct mib_node* const internet_nodes[2] = { (struct mib_node*)&mgmt, (struct mib_node*)&mib_private };
+const struct mib_array_node internet = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  2,
+  internet_ids,
+  internet_nodes
+};
+#else
+const s32_t internet_ids[1] = { 2 };
+struct mib_node* const internet_nodes[1] = { (struct mib_node*)&mgmt };
+const struct mib_array_node internet = {
+  &noleafs_get_object_def,
+  &noleafs_get_value,
+  &noleafs_set_test,
+  &noleafs_set_value,
+  MIB_NODE_AR,
+  1,
+  internet_ids,
+  internet_nodes
+};
+#endif
+
+/** mib-2.system.sysObjectID  */
+static struct snmp_obj_id sysobjid = {SNMP_SYSOBJID_LEN, SNMP_SYSOBJID};
+/** enterprise ID for generic TRAPs, .iso.org.dod.internet.mgmt.mib-2.snmp */
+static struct snmp_obj_id snmpgrp_id = {7,{1,3,6,1,2,1,11}};
+/** mib-2.system.sysServices */
+static const s32_t sysservices = SNMP_SYSSERVICES;
+
+/** mib-2.system.sysDescr */
+static const u8_t sysdescr_len_default = 4;
+static const u8_t sysdescr_default[] = "lwIP";
+static u8_t* sysdescr_len_ptr = (u8_t*)&sysdescr_len_default;
+static u8_t* sysdescr_ptr = (u8_t*)&sysdescr_default[0];
+/** mib-2.system.sysContact */
+static const u8_t syscontact_len_default = 0;
+static const u8_t syscontact_default[] = "";
+static u8_t* syscontact_len_ptr = (u8_t*)&syscontact_len_default;
+static u8_t* syscontact_ptr = (u8_t*)&syscontact_default[0];
+/** mib-2.system.sysName */
+static const u8_t sysname_len_default = 8;
+static const u8_t sysname_default[] = "FQDN-unk";
+static u8_t* sysname_len_ptr = (u8_t*)&sysname_len_default;
+static u8_t* sysname_ptr = (u8_t*)&sysname_default[0];
+/** mib-2.system.sysLocation */
+static const u8_t syslocation_len_default = 0;
+static const u8_t syslocation_default[] = "";
+static u8_t* syslocation_len_ptr = (u8_t*)&syslocation_len_default;
+static u8_t* syslocation_ptr = (u8_t*)&syslocation_default[0];
+/** mib-2.snmp.snmpEnableAuthenTraps */
+static const u8_t snmpenableauthentraps_default = 2; /* disabled */
+static u8_t* snmpenableauthentraps_ptr = (u8_t*)&snmpenableauthentraps_default;
+
+/** mib-2.interfaces.ifTable.ifEntry.ifSpecific (zeroDotZero) */
+static const struct snmp_obj_id ifspecific = {2, {0, 0}};
+/** mib-2.ip.ipRouteTable.ipRouteEntry.ipRouteInfo (zeroDotZero) */
+static const struct snmp_obj_id iprouteinfo = {2, {0, 0}};
+
+
+
+/* mib-2.system counter(s) */
+static u32_t sysuptime = 0;
+
+/* mib-2.ip counter(s) */
+static u32_t ipinreceives = 0,
+             ipinhdrerrors = 0,
+             ipinaddrerrors = 0,
+             ipforwdatagrams = 0,
+             ipinunknownprotos = 0,
+             ipindiscards = 0,
+             ipindelivers = 0,
+             ipoutrequests = 0,
+             ipoutdiscards = 0,
+             ipoutnoroutes = 0,
+             ipreasmreqds = 0,
+             ipreasmoks = 0,
+             ipreasmfails = 0,
+             ipfragoks = 0,
+             ipfragfails = 0,
+             ipfragcreates = 0,
+             iproutingdiscards = 0;
+/* mib-2.icmp counter(s) */
+static u32_t icmpinmsgs = 0,
+             icmpinerrors = 0,
+             icmpindestunreachs = 0,
+             icmpintimeexcds = 0,
+             icmpinparmprobs = 0,
+             icmpinsrcquenchs = 0,
+             icmpinredirects = 0,
+             icmpinechos = 0,
+             icmpinechoreps = 0,
+             icmpintimestamps = 0,
+             icmpintimestampreps = 0,
+             icmpinaddrmasks = 0,
+             icmpinaddrmaskreps = 0,
+             icmpoutmsgs = 0,
+             icmpouterrors = 0,
+             icmpoutdestunreachs = 0,
+             icmpouttimeexcds = 0,
+             icmpoutparmprobs = 0,
+             icmpoutsrcquenchs = 0,
+             icmpoutredirects = 0,
+             icmpoutechos = 0,
+             icmpoutechoreps = 0,
+             icmpouttimestamps = 0,
+             icmpouttimestampreps = 0,
+             icmpoutaddrmasks = 0,
+             icmpoutaddrmaskreps = 0;
+/* mib-2.tcp counter(s) */
+static u32_t tcpactiveopens = 0,
+             tcppassiveopens = 0,
+             tcpattemptfails = 0,
+             tcpestabresets = 0,
+             tcpinsegs = 0,
+             tcpoutsegs = 0,
+             tcpretranssegs = 0,
+             tcpinerrs = 0,
+             tcpoutrsts = 0;
+/* mib-2.udp counter(s) */
+static u32_t udpindatagrams = 0,
+             udpnoports = 0,
+             udpinerrors = 0,
+             udpoutdatagrams = 0;
+/* mib-2.snmp counter(s) */
+static u32_t snmpinpkts = 0,
+             snmpoutpkts = 0,
+             snmpinbadversions = 0,
+             snmpinbadcommunitynames = 0,
+             snmpinbadcommunityuses = 0,
+             snmpinasnparseerrs = 0,
+             snmpintoobigs = 0,
+             snmpinnosuchnames = 0,
+             snmpinbadvalues = 0,
+             snmpinreadonlys = 0,
+             snmpingenerrs = 0,
+             snmpintotalreqvars = 0,
+             snmpintotalsetvars = 0,
+             snmpingetrequests = 0,
+             snmpingetnexts = 0,
+             snmpinsetrequests = 0,
+             snmpingetresponses = 0,
+             snmpintraps = 0,
+             snmpouttoobigs = 0,
+             snmpoutnosuchnames = 0,
+             snmpoutbadvalues = 0,
+             snmpoutgenerrs = 0,
+             snmpoutgetrequests = 0,
+             snmpoutgetnexts = 0,
+             snmpoutsetrequests = 0,
+             snmpoutgetresponses = 0,
+             snmpouttraps = 0;
+
+
+
+/* prototypes of the following functions are in lwip/src/include/lwip/snmp.h */
+/**
+ * Copy octet string.
+ *
+ * @param dst points to destination
+ * @param src points to source
+ * @param n number of octets to copy.
+ */
+static void ocstrncpy(u8_t *dst, u8_t *src, u16_t n)
+{
+  u16_t i = n;
+  while (i > 0) {
+    i--;
+    *dst++ = *src++;
+  }
+}
+
+/**
+ * Copy object identifier (s32_t) array.
+ *
+ * @param dst points to destination
+ * @param src points to source
+ * @param n number of sub identifiers to copy.
+ */
+void objectidncpy(s32_t *dst, s32_t *src, u8_t n)
+{
+  u8_t i = n;
+  while(i > 0) {
+    i--;
+    *dst++ = *src++;
+  }
+}
+
+/**
+ * Initializes sysDescr pointers.
+ *
+ * @param str if non-NULL then copy str pointer
+ * @param len points to string length, excluding zero terminator
+ */
+void snmp_set_sysdesr(u8_t *str, u8_t *len)
+{
+  if (str != NULL)
+  {
+    sysdescr_ptr = str;
+    sysdescr_len_ptr = len;
+  }
+}
+
+void snmp_get_sysobjid_ptr(struct snmp_obj_id **oid)
+{
+  *oid = &sysobjid;
+}
+
+/**
+ * Initializes sysObjectID value.
+ *
+ * @param oid points to stuct snmp_obj_id to copy
+ */
+void snmp_set_sysobjid(struct snmp_obj_id *oid)
+{
+  sysobjid = *oid;
+}
+
+/**
+ * Must be called at regular 10 msec interval from a timer interrupt
+ * or signal handler depending on your runtime environment.
+ */
+void snmp_inc_sysuptime(void)
+{
+  sysuptime++;
+}
+
+void snmp_add_sysuptime(u32_t value)
+{
+  sysuptime+=value;
+}
+
+void snmp_get_sysuptime(u32_t *value)
+{
+  SNMP_GET_SYSUPTIME(sysuptime);
+  *value = sysuptime;
+}
+
+/**
+ * Initializes sysContact pointers,
+ * e.g. ptrs to non-volatile memory external to lwIP.
+ *
+ * @param ocstr if non-NULL then copy str pointer
+ * @param ocstrlen points to string length, excluding zero terminator
+ */
+void snmp_set_syscontact(u8_t *ocstr, u8_t *ocstrlen)
+{
+  if (ocstr != NULL)
+  {
+    syscontact_ptr = ocstr;
+    syscontact_len_ptr = ocstrlen;
+  }
+}
+
+/**
+ * Initializes sysName pointers,
+ * e.g. ptrs to non-volatile memory external to lwIP.
+ *
+ * @param ocstr if non-NULL then copy str pointer
+ * @param ocstrlen points to string length, excluding zero terminator
+ */
+void snmp_set_sysname(u8_t *ocstr, u8_t *ocstrlen)
+{
+  if (ocstr != NULL)
+  {
+    sysname_ptr = ocstr;
+    sysname_len_ptr = ocstrlen;
+  }
+}
+
+/**
+ * Initializes sysLocation pointers,
+ * e.g. ptrs to non-volatile memory external to lwIP.
+ *
+ * @param ocstr if non-NULL then copy str pointer
+ * @param ocstrlen points to string length, excluding zero terminator
+ */
+void snmp_set_syslocation(u8_t *ocstr, u8_t *ocstrlen)
+{
+  if (ocstr != NULL)
+  {
+    syslocation_ptr = ocstr;
+    syslocation_len_ptr = ocstrlen;
+  }
+}
+
+
+void snmp_add_ifinoctets(struct netif *ni, u32_t value)
+{
+  ni->ifinoctets += value;
+}
+
+void snmp_inc_ifinucastpkts(struct netif *ni)
+{
+  (ni->ifinucastpkts)++;
+}
+
+void snmp_inc_ifinnucastpkts(struct netif *ni)
+{
+  (ni->ifinnucastpkts)++;
+}
+
+void snmp_inc_ifindiscards(struct netif *ni)
+{
+  (ni->ifindiscards)++;
+}
+
+void snmp_add_ifoutoctets(struct netif *ni, u32_t value)
+{
+  ni->ifoutoctets += value;
+}
+
+void snmp_inc_ifoutucastpkts(struct netif *ni)
+{
+  (ni->ifoutucastpkts)++;
+}
+
+void snmp_inc_ifoutnucastpkts(struct netif *ni)
+{
+  (ni->ifoutnucastpkts)++;
+}
+
+void snmp_inc_ifoutdiscards(struct netif *ni)
+{
+  (ni->ifoutdiscards)++;
+}
+
+void snmp_inc_iflist(void)
+{
+  struct mib_list_node *if_node = NULL;
+
+  snmp_mib_node_insert(&iflist_root, iflist_root.count + 1, &if_node);
+  /* enable getnext traversal on filled table */
+  iftable.maxlength = 1;
+}
+
+void snmp_dec_iflist(void)
+{
+  snmp_mib_node_delete(&iflist_root, iflist_root.tail);
+  /* disable getnext traversal on empty table */
+  if(iflist_root.count == 0) iftable.maxlength = 0;
+}
+
+/**
+ * Inserts ARP table indexes (.xIfIndex.xNetAddress)
+ * into arp table index trees (both atTable and ipNetToMediaTable).
+ */
+void snmp_insert_arpidx_tree(struct netif *ni, ip_addr_t *ip)
+{
+  struct mib_list_rootnode *at_rn;
+  struct mib_list_node *at_node;
+  s32_t arpidx[5];
+  u8_t level, tree;
+
+  LWIP_ASSERT("ni != NULL", ni != NULL);
+  snmp_netiftoifindex(ni, &arpidx[0]);
+  snmp_iptooid(ip, &arpidx[1]);
+
+  for (tree = 0; tree < 2; tree++)
+  {
+    if (tree == 0)
+    {
+      at_rn = &arptree_root;
+    }
+    else
+    {
+      at_rn = &ipntomtree_root;
+    }
+    for (level = 0; level < 5; level++)
+    {
+      at_node = NULL;
+      snmp_mib_node_insert(at_rn, arpidx[level], &at_node);
+      if ((level != 4) && (at_node != NULL))
+      {
+        if (at_node->nptr == NULL)
+        {
+          at_rn = snmp_mib_lrn_alloc();
+          at_node->nptr = (struct mib_node*)at_rn;
+          if (at_rn != NULL)
+          {
+            if (level == 3)
+            {
+              if (tree == 0)
+              {
+                at_rn->get_object_def = atentry_get_object_def;
+                at_rn->get_value = atentry_get_value;
+              }
+              else
+              {
+                at_rn->get_object_def = ip_ntomentry_get_object_def;
+                at_rn->get_value = ip_ntomentry_get_value;
+              }
+              at_rn->set_test = noleafs_set_test;
+              at_rn->set_value = noleafs_set_value;
+            }
+          }
+          else
+          {
+            /* at_rn == NULL, malloc failure */
+            LWIP_DEBUGF(SNMP_MIB_DEBUG,("snmp_insert_arpidx_tree() insert failed, mem full"));
+            break;
+          }
+        }
+        else
+        {
+          at_rn = (struct mib_list_rootnode*)at_node->nptr;
+        }
+      }
+    }
+  }
+  /* enable getnext traversal on filled tables */
+  at.maxlength = 1;
+  ipntomtable.maxlength = 1;
+}
+
+/**
+ * Removes ARP table indexes (.xIfIndex.xNetAddress)
+ * from arp table index trees.
+ */
+void snmp_delete_arpidx_tree(struct netif *ni, ip_addr_t *ip)
+{
+  struct mib_list_rootnode *at_rn, *next, *del_rn[5];
+  struct mib_list_node *at_n, *del_n[5];
+  s32_t arpidx[5];
+  u8_t fc, tree, level, del_cnt;
+
+  snmp_netiftoifindex(ni, &arpidx[0]);
+  snmp_iptooid(ip, &arpidx[1]);
+
+  for (tree = 0; tree < 2; tree++)
+  {
+    /* mark nodes for deletion */
+    if (tree == 0)
+    {
+      at_rn = &arptree_root;
+    }
+    else
+    {
+      at_rn = &ipntomtree_root;
+    }
+    level = 0;
+    del_cnt = 0;
+    while ((level < 5) && (at_rn != NULL))
+    {
+      fc = snmp_mib_node_find(at_rn, arpidx[level], &at_n);
+      if (fc == 0)
+      {
+        /* arpidx[level] does not exist */
+        del_cnt = 0;
+        at_rn = NULL;
+      }
+      else if (fc == 1)
+      {
+        del_rn[del_cnt] = at_rn;
+        del_n[del_cnt] = at_n;
+        del_cnt++;
+        at_rn = (struct mib_list_rootnode*)(at_n->nptr);
+      }
+      else if (fc == 2)
+      {
+        /* reset delete (2 or more childs) */
+        del_cnt = 0;
+        at_rn = (struct mib_list_rootnode*)(at_n->nptr);
+      }
+      level++;
+    }
+    /* delete marked index nodes */
+    while (del_cnt > 0)
+    {
+      del_cnt--;
+
+      at_rn = del_rn[del_cnt];
+      at_n = del_n[del_cnt];
+
+      next = snmp_mib_node_delete(at_rn, at_n);
+      if (next != NULL)
+      {
+        LWIP_ASSERT("next_count == 0",next->count == 0);
+        snmp_mib_lrn_free(next);
+      }
+    }
+  }
+  /* disable getnext traversal on empty tables */
+  if(arptree_root.count == 0) at.maxlength = 0;
+  if(ipntomtree_root.count == 0) ipntomtable.maxlength = 0;
+}
+
+void snmp_inc_ipinreceives(void)
+{
+  ipinreceives++;
+}
+
+void snmp_inc_ipinhdrerrors(void)
+{
+  ipinhdrerrors++;
+}
+
+void snmp_inc_ipinaddrerrors(void)
+{
+  ipinaddrerrors++;
+}
+
+void snmp_inc_ipforwdatagrams(void)
+{
+  ipforwdatagrams++;
+}
+
+void snmp_inc_ipinunknownprotos(void)
+{
+  ipinunknownprotos++;
+}
+
+void snmp_inc_ipindiscards(void)
+{
+  ipindiscards++;
+}
+
+void snmp_inc_ipindelivers(void)
+{
+  ipindelivers++;
+}
+
+void snmp_inc_ipoutrequests(void)
+{
+  ipoutrequests++;
+}
+
+void snmp_inc_ipoutdiscards(void)
+{
+  ipoutdiscards++;
+}
+
+void snmp_inc_ipoutnoroutes(void)
+{
+  ipoutnoroutes++;
+}
+
+void snmp_inc_ipreasmreqds(void)
+{
+  ipreasmreqds++;
+}
+
+void snmp_inc_ipreasmoks(void)
+{
+  ipreasmoks++;
+}
+
+void snmp_inc_ipreasmfails(void)
+{
+  ipreasmfails++;
+}
+
+void snmp_inc_ipfragoks(void)
+{
+  ipfragoks++;
+}
+
+void snmp_inc_ipfragfails(void)
+{
+  ipfragfails++;
+}
+
+void snmp_inc_ipfragcreates(void)
+{
+  ipfragcreates++;
+}
+
+void snmp_inc_iproutingdiscards(void)
+{
+  iproutingdiscards++;
+}
+
+/**
+ * Inserts ipAddrTable indexes (.ipAdEntAddr)
+ * into index tree.
+ */
+void snmp_insert_ipaddridx_tree(struct netif *ni)
+{
+  struct mib_list_rootnode *ipa_rn;
+  struct mib_list_node *ipa_node;
+  s32_t ipaddridx[4];
+  u8_t level;
+
+  LWIP_ASSERT("ni != NULL", ni != NULL);
+  snmp_iptooid(&ni->ip_addr, &ipaddridx[0]);
+
+  level = 0;
+  ipa_rn = &ipaddrtree_root;
+  while (level < 4)
+  {
+    ipa_node = NULL;
+    snmp_mib_node_insert(ipa_rn, ipaddridx[level], &ipa_node);
+    if ((level != 3) && (ipa_node != NULL))
+    {
+      if (ipa_node->nptr == NULL)
+      {
+        ipa_rn = snmp_mib_lrn_alloc();
+        ipa_node->nptr = (struct mib_node*)ipa_rn;
+        if (ipa_rn != NULL)
+        {
+          if (level == 2)
+          {
+            ipa_rn->get_object_def = ip_addrentry_get_object_def;
+            ipa_rn->get_value = ip_addrentry_get_value;
+            ipa_rn->set_test = noleafs_set_test;
+            ipa_rn->set_value = noleafs_set_value;
+          }
+        }
+        else
+        {
+          /* ipa_rn == NULL, malloc failure */
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("snmp_insert_ipaddridx_tree() insert failed, mem full"));
+          break;
+        }
+      }
+      else
+      {
+        ipa_rn = (struct mib_list_rootnode*)ipa_node->nptr;
+      }
+    }
+    level++;
+  }
+  /* enable getnext traversal on filled table */
+  ipaddrtable.maxlength = 1;
+}
+
+/**
+ * Removes ipAddrTable indexes (.ipAdEntAddr)
+ * from index tree.
+ */
+void snmp_delete_ipaddridx_tree(struct netif *ni)
+{
+  struct mib_list_rootnode *ipa_rn, *next, *del_rn[4];
+  struct mib_list_node *ipa_n, *del_n[4];
+  s32_t ipaddridx[4];
+  u8_t fc, level, del_cnt;
+
+  LWIP_ASSERT("ni != NULL", ni != NULL);
+  snmp_iptooid(&ni->ip_addr, &ipaddridx[0]);
+
+  /* mark nodes for deletion */
+  level = 0;
+  del_cnt = 0;
+  ipa_rn = &ipaddrtree_root;
+  while ((level < 4) && (ipa_rn != NULL))
+  {
+    fc = snmp_mib_node_find(ipa_rn, ipaddridx[level], &ipa_n);
+    if (fc == 0)
+    {
+      /* ipaddridx[level] does not exist */
+      del_cnt = 0;
+      ipa_rn = NULL;
+    }
+    else if (fc == 1)
+    {
+      del_rn[del_cnt] = ipa_rn;
+      del_n[del_cnt] = ipa_n;
+      del_cnt++;
+      ipa_rn = (struct mib_list_rootnode*)(ipa_n->nptr);
+    }
+    else if (fc == 2)
+    {
+      /* reset delete (2 or more childs) */
+      del_cnt = 0;
+      ipa_rn = (struct mib_list_rootnode*)(ipa_n->nptr);
+    }
+    level++;
+  }
+  /* delete marked index nodes */
+  while (del_cnt > 0)
+  {
+    del_cnt--;
+
+    ipa_rn = del_rn[del_cnt];
+    ipa_n = del_n[del_cnt];
+
+    next = snmp_mib_node_delete(ipa_rn, ipa_n);
+    if (next != NULL)
+    {
+      LWIP_ASSERT("next_count == 0",next->count == 0);
+      snmp_mib_lrn_free(next);
+    }
+  }
+  /* disable getnext traversal on empty table */
+  if (ipaddrtree_root.count == 0) ipaddrtable.maxlength = 0;
+}
+
+/**
+ * Inserts ipRouteTable indexes (.ipRouteDest)
+ * into index tree.
+ *
+ * @param dflt non-zero for the default rte, zero for network rte
+ * @param ni points to network interface for this rte
+ *
+ * @todo record sysuptime for _this_ route when it is installed
+ *   (needed for ipRouteAge) in the netif.
+ */
+void snmp_insert_iprteidx_tree(u8_t dflt, struct netif *ni)
+{
+  u8_t insert = 0;
+  ip_addr_t dst;
+
+  if (dflt != 0)
+  {
+    /* the default route 0.0.0.0 */
+    ip_addr_set_any(&dst);
+    insert = 1;
+  }
+  else
+  {
+    /* route to the network address */
+    ip_addr_get_network(&dst, &ni->ip_addr, &ni->netmask);
+    /* exclude 0.0.0.0 network (reserved for default rte) */
+    if (!ip_addr_isany(&dst)) {
+      insert = 1;
+    }
+  }
+  if (insert)
+  {
+    struct mib_list_rootnode *iprte_rn;
+    struct mib_list_node *iprte_node;
+    s32_t iprteidx[4];
+    u8_t level;
+
+    snmp_iptooid(&dst, &iprteidx[0]);
+    level = 0;
+    iprte_rn = &iprtetree_root;
+    while (level < 4)
+    {
+      iprte_node = NULL;
+      snmp_mib_node_insert(iprte_rn, iprteidx[level], &iprte_node);
+      if ((level != 3) && (iprte_node != NULL))
+      {
+        if (iprte_node->nptr == NULL)
+        {
+          iprte_rn = snmp_mib_lrn_alloc();
+          iprte_node->nptr = (struct mib_node*)iprte_rn;
+          if (iprte_rn != NULL)
+          {
+            if (level == 2)
+            {
+              iprte_rn->get_object_def = ip_rteentry_get_object_def;
+              iprte_rn->get_value = ip_rteentry_get_value;
+              iprte_rn->set_test = noleafs_set_test;
+              iprte_rn->set_value = noleafs_set_value;
+            }
+          }
+          else
+          {
+            /* iprte_rn == NULL, malloc failure */
+            LWIP_DEBUGF(SNMP_MIB_DEBUG,("snmp_insert_iprteidx_tree() insert failed, mem full"));
+            break;
+          }
+        }
+        else
+        {
+          iprte_rn = (struct mib_list_rootnode*)iprte_node->nptr;
+        }
+      }
+      level++;
+    }
+  }
+  /* enable getnext traversal on filled table */
+  iprtetable.maxlength = 1;
+}
+
+/**
+ * Removes ipRouteTable indexes (.ipRouteDest)
+ * from index tree.
+ *
+ * @param dflt non-zero for the default rte, zero for network rte
+ * @param ni points to network interface for this rte or NULL
+ *   for default route to be removed.
+ */
+void snmp_delete_iprteidx_tree(u8_t dflt, struct netif *ni)
+{
+  u8_t del = 0;
+  ip_addr_t dst;
+
+  if (dflt != 0)
+  {
+    /* the default route 0.0.0.0 */
+    ip_addr_set_any(&dst);
+    del = 1;
+  }
+  else
+  {
+    /* route to the network address */
+    ip_addr_get_network(&dst, &ni->ip_addr, &ni->netmask);
+    /* exclude 0.0.0.0 network (reserved for default rte) */
+    if (!ip_addr_isany(&dst)) {
+      del = 1;
+    }
+  }
+  if (del)
+  {
+    struct mib_list_rootnode *iprte_rn, *next, *del_rn[4];
+    struct mib_list_node *iprte_n, *del_n[4];
+    s32_t iprteidx[4];
+    u8_t fc, level, del_cnt;
+
+    snmp_iptooid(&dst, &iprteidx[0]);
+    /* mark nodes for deletion */
+    level = 0;
+    del_cnt = 0;
+    iprte_rn = &iprtetree_root;
+    while ((level < 4) && (iprte_rn != NULL))
+    {
+      fc = snmp_mib_node_find(iprte_rn, iprteidx[level], &iprte_n);
+      if (fc == 0)
+      {
+        /* iprteidx[level] does not exist */
+        del_cnt = 0;
+        iprte_rn = NULL;
+      }
+      else if (fc == 1)
+      {
+        del_rn[del_cnt] = iprte_rn;
+        del_n[del_cnt] = iprte_n;
+        del_cnt++;
+        iprte_rn = (struct mib_list_rootnode*)(iprte_n->nptr);
+      }
+      else if (fc == 2)
+      {
+        /* reset delete (2 or more childs) */
+        del_cnt = 0;
+        iprte_rn = (struct mib_list_rootnode*)(iprte_n->nptr);
+      }
+      level++;
+    }
+    /* delete marked index nodes */
+    while (del_cnt > 0)
+    {
+      del_cnt--;
+
+      iprte_rn = del_rn[del_cnt];
+      iprte_n = del_n[del_cnt];
+
+      next = snmp_mib_node_delete(iprte_rn, iprte_n);
+      if (next != NULL)
+      {
+        LWIP_ASSERT("next_count == 0",next->count == 0);
+        snmp_mib_lrn_free(next);
+      }
+    }
+  }
+  /* disable getnext traversal on empty table */
+  if (iprtetree_root.count == 0) iprtetable.maxlength = 0;
+}
+
+
+void snmp_inc_icmpinmsgs(void)
+{
+  icmpinmsgs++;
+}
+
+void snmp_inc_icmpinerrors(void)
+{
+  icmpinerrors++;
+}
+
+void snmp_inc_icmpindestunreachs(void)
+{
+  icmpindestunreachs++;
+}
+
+void snmp_inc_icmpintimeexcds(void)
+{
+  icmpintimeexcds++;
+}
+
+void snmp_inc_icmpinparmprobs(void)
+{
+  icmpinparmprobs++;
+}
+
+void snmp_inc_icmpinsrcquenchs(void)
+{
+  icmpinsrcquenchs++;
+}
+
+void snmp_inc_icmpinredirects(void)
+{
+  icmpinredirects++;
+}
+
+void snmp_inc_icmpinechos(void)
+{
+  icmpinechos++;
+}
+
+void snmp_inc_icmpinechoreps(void)
+{
+  icmpinechoreps++;
+}
+
+void snmp_inc_icmpintimestamps(void)
+{
+  icmpintimestamps++;
+}
+
+void snmp_inc_icmpintimestampreps(void)
+{
+  icmpintimestampreps++;
+}
+
+void snmp_inc_icmpinaddrmasks(void)
+{
+  icmpinaddrmasks++;
+}
+
+void snmp_inc_icmpinaddrmaskreps(void)
+{
+  icmpinaddrmaskreps++;
+}
+
+void snmp_inc_icmpoutmsgs(void)
+{
+  icmpoutmsgs++;
+}
+
+void snmp_inc_icmpouterrors(void)
+{
+  icmpouterrors++;
+}
+
+void snmp_inc_icmpoutdestunreachs(void)
+{
+  icmpoutdestunreachs++;
+}
+
+void snmp_inc_icmpouttimeexcds(void)
+{
+  icmpouttimeexcds++;
+}
+
+void snmp_inc_icmpoutparmprobs(void)
+{
+  icmpoutparmprobs++;
+}
+
+void snmp_inc_icmpoutsrcquenchs(void)
+{
+  icmpoutsrcquenchs++;
+}
+
+void snmp_inc_icmpoutredirects(void)
+{
+  icmpoutredirects++;
+}
+
+void snmp_inc_icmpoutechos(void)
+{
+  icmpoutechos++;
+}
+
+void snmp_inc_icmpoutechoreps(void)
+{
+  icmpoutechoreps++;
+}
+
+void snmp_inc_icmpouttimestamps(void)
+{
+  icmpouttimestamps++;
+}
+
+void snmp_inc_icmpouttimestampreps(void)
+{
+  icmpouttimestampreps++;
+}
+
+void snmp_inc_icmpoutaddrmasks(void)
+{
+  icmpoutaddrmasks++;
+}
+
+void snmp_inc_icmpoutaddrmaskreps(void)
+{
+  icmpoutaddrmaskreps++;
+}
+
+void snmp_inc_tcpactiveopens(void)
+{
+  tcpactiveopens++;
+}
+
+void snmp_inc_tcppassiveopens(void)
+{
+  tcppassiveopens++;
+}
+
+void snmp_inc_tcpattemptfails(void)
+{
+  tcpattemptfails++;
+}
+
+void snmp_inc_tcpestabresets(void)
+{
+  tcpestabresets++;
+}
+
+void snmp_inc_tcpinsegs(void)
+{
+  tcpinsegs++;
+}
+
+void snmp_inc_tcpoutsegs(void)
+{
+  tcpoutsegs++;
+}
+
+void snmp_inc_tcpretranssegs(void)
+{
+  tcpretranssegs++;
+}
+
+void snmp_inc_tcpinerrs(void)
+{
+  tcpinerrs++;
+}
+
+void snmp_inc_tcpoutrsts(void)
+{
+  tcpoutrsts++;
+}
+
+void snmp_inc_udpindatagrams(void)
+{
+  udpindatagrams++;
+}
+
+void snmp_inc_udpnoports(void)
+{
+  udpnoports++;
+}
+
+void snmp_inc_udpinerrors(void)
+{
+  udpinerrors++;
+}
+
+void snmp_inc_udpoutdatagrams(void)
+{
+  udpoutdatagrams++;
+}
+
+/**
+ * Inserts udpTable indexes (.udpLocalAddress.udpLocalPort)
+ * into index tree.
+ */
+void snmp_insert_udpidx_tree(struct udp_pcb *pcb)
+{
+  struct mib_list_rootnode *udp_rn;
+  struct mib_list_node *udp_node;
+  s32_t udpidx[5];
+  u8_t level;
+
+  LWIP_ASSERT("pcb != NULL", pcb != NULL);
+  snmp_iptooid(&pcb->local_ip, &udpidx[0]);
+  udpidx[4] = pcb->local_port;
+
+  udp_rn = &udp_root;
+  for (level = 0; level < 5; level++)
+  {
+    udp_node = NULL;
+    snmp_mib_node_insert(udp_rn, udpidx[level], &udp_node);
+    if ((level != 4) && (udp_node != NULL))
+    {
+      if (udp_node->nptr == NULL)
+      {
+        udp_rn = snmp_mib_lrn_alloc();
+        udp_node->nptr = (struct mib_node*)udp_rn;
+        if (udp_rn != NULL)
+        {
+          if (level == 3)
+          {
+            udp_rn->get_object_def = udpentry_get_object_def;
+            udp_rn->get_value = udpentry_get_value;
+            udp_rn->set_test = noleafs_set_test;
+            udp_rn->set_value = noleafs_set_value;
+          }
+        }
+        else
+        {
+          /* udp_rn == NULL, malloc failure */
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("snmp_insert_udpidx_tree() insert failed, mem full"));
+          break;
+        }
+      }
+      else
+      {
+        udp_rn = (struct mib_list_rootnode*)udp_node->nptr;
+      }
+    }
+  }
+  udptable.maxlength = 1;
+}
+
+/**
+ * Removes udpTable indexes (.udpLocalAddress.udpLocalPort)
+ * from index tree.
+ */
+void snmp_delete_udpidx_tree(struct udp_pcb *pcb)
+{
+  struct udp_pcb *npcb;
+  struct mib_list_rootnode *udp_rn, *next, *del_rn[5];
+  struct mib_list_node *udp_n, *del_n[5];
+  s32_t udpidx[5];
+  u8_t bindings, fc, level, del_cnt;
+
+  LWIP_ASSERT("pcb != NULL", pcb != NULL);
+  snmp_iptooid(&pcb->local_ip, &udpidx[0]);
+  udpidx[4] = pcb->local_port;
+
+  /* count PCBs for a given binding
+     (e.g. when reusing ports or for temp output PCBs) */
+  bindings = 0;
+  npcb = udp_pcbs;
+  while ((npcb != NULL))
+  {
+    if (ip_addr_cmp(&npcb->local_ip, &pcb->local_ip) &&
+        (npcb->local_port == udpidx[4]))
+    {
+      bindings++;
+    }
+    npcb = npcb->next;
+  }
+  if (bindings == 1)
+  {
+    /* selectively remove */
+    /* mark nodes for deletion */
+    level = 0;
+    del_cnt = 0;
+    udp_rn = &udp_root;
+    while ((level < 5) && (udp_rn != NULL))
+    {
+      fc = snmp_mib_node_find(udp_rn, udpidx[level], &udp_n);
+      if (fc == 0)
+      {
+        /* udpidx[level] does not exist */
+        del_cnt = 0;
+        udp_rn = NULL;
+      }
+      else if (fc == 1)
+      {
+        del_rn[del_cnt] = udp_rn;
+        del_n[del_cnt] = udp_n;
+        del_cnt++;
+        udp_rn = (struct mib_list_rootnode*)(udp_n->nptr);
+      }
+      else if (fc == 2)
+      {
+        /* reset delete (2 or more childs) */
+        del_cnt = 0;
+        udp_rn = (struct mib_list_rootnode*)(udp_n->nptr);
+      }
+      level++;
+    }
+    /* delete marked index nodes */
+    while (del_cnt > 0)
+    {
+      del_cnt--;
+
+      udp_rn = del_rn[del_cnt];
+      udp_n = del_n[del_cnt];
+
+      next = snmp_mib_node_delete(udp_rn, udp_n);
+      if (next != NULL)
+      {
+        LWIP_ASSERT("next_count == 0",next->count == 0);
+        snmp_mib_lrn_free(next);
+      }
+    }
+  }
+  /* disable getnext traversal on empty table */
+  if (udp_root.count == 0) udptable.maxlength = 0;
+}
+
+
+void snmp_inc_snmpinpkts(void)
+{
+  snmpinpkts++;
+}
+
+void snmp_inc_snmpoutpkts(void)
+{
+  snmpoutpkts++;
+}
+
+void snmp_inc_snmpinbadversions(void)
+{
+  snmpinbadversions++;
+}
+
+void snmp_inc_snmpinbadcommunitynames(void)
+{
+  snmpinbadcommunitynames++;
+}
+
+void snmp_inc_snmpinbadcommunityuses(void)
+{
+  snmpinbadcommunityuses++;
+}
+
+void snmp_inc_snmpinasnparseerrs(void)
+{
+  snmpinasnparseerrs++;
+}
+
+void snmp_inc_snmpintoobigs(void)
+{
+  snmpintoobigs++;
+}
+
+void snmp_inc_snmpinnosuchnames(void)
+{
+  snmpinnosuchnames++;
+}
+
+void snmp_inc_snmpinbadvalues(void)
+{
+  snmpinbadvalues++;
+}
+
+void snmp_inc_snmpinreadonlys(void)
+{
+  snmpinreadonlys++;
+}
+
+void snmp_inc_snmpingenerrs(void)
+{
+  snmpingenerrs++;
+}
+
+void snmp_add_snmpintotalreqvars(u8_t value)
+{
+  snmpintotalreqvars += value;
+}
+
+void snmp_add_snmpintotalsetvars(u8_t value)
+{
+  snmpintotalsetvars += value;
+}
+
+void snmp_inc_snmpingetrequests(void)
+{
+  snmpingetrequests++;
+}
+
+void snmp_inc_snmpingetnexts(void)
+{
+  snmpingetnexts++;
+}
+
+void snmp_inc_snmpinsetrequests(void)
+{
+  snmpinsetrequests++;
+}
+
+void snmp_inc_snmpingetresponses(void)
+{
+  snmpingetresponses++;
+}
+
+void snmp_inc_snmpintraps(void)
+{
+  snmpintraps++;
+}
+
+void snmp_inc_snmpouttoobigs(void)
+{
+  snmpouttoobigs++;
+}
+
+void snmp_inc_snmpoutnosuchnames(void)
+{
+  snmpoutnosuchnames++;
+}
+
+void snmp_inc_snmpoutbadvalues(void)
+{
+  snmpoutbadvalues++;
+}
+
+void snmp_inc_snmpoutgenerrs(void)
+{
+  snmpoutgenerrs++;
+}
+
+void snmp_inc_snmpoutgetrequests(void)
+{
+  snmpoutgetrequests++;
+}
+
+void snmp_inc_snmpoutgetnexts(void)
+{
+  snmpoutgetnexts++;
+}
+
+void snmp_inc_snmpoutsetrequests(void)
+{
+  snmpoutsetrequests++;
+}
+
+void snmp_inc_snmpoutgetresponses(void)
+{
+  snmpoutgetresponses++;
+}
+
+void snmp_inc_snmpouttraps(void)
+{
+  snmpouttraps++;
+}
+
+void snmp_get_snmpgrpid_ptr(struct snmp_obj_id **oid)
+{
+  *oid = &snmpgrp_id;
+}
+
+void snmp_set_snmpenableauthentraps(u8_t *value)
+{
+  if (value != NULL)
+  {
+    snmpenableauthentraps_ptr = value;
+  }
+}
+
+void snmp_get_snmpenableauthentraps(u8_t *value)
+{
+  *value = *snmpenableauthentraps_ptr;
+}
+
+void
+noleafs_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od)
+{
+  LWIP_UNUSED_ARG(ident_len);
+  LWIP_UNUSED_ARG(ident);
+  od->instance = MIB_OBJECT_NONE;
+}
+
+void
+noleafs_get_value(struct obj_def *od, u16_t len, void *value)
+{
+  LWIP_UNUSED_ARG(od);
+  LWIP_UNUSED_ARG(len);
+  LWIP_UNUSED_ARG(value);
+}
+
+u8_t
+noleafs_set_test(struct obj_def *od, u16_t len, void *value)
+{
+  LWIP_UNUSED_ARG(od);
+  LWIP_UNUSED_ARG(len);
+  LWIP_UNUSED_ARG(value);
+  /* can't set */
+  return 0;
+}
+
+void
+noleafs_set_value(struct obj_def *od, u16_t len, void *value)
+{
+  LWIP_UNUSED_ARG(od);
+  LWIP_UNUSED_ARG(len);
+  LWIP_UNUSED_ARG(value);
+}
+
+
+/**
+ * Returns systems object definitions.
+ *
+ * @param ident_len the address length (2)
+ * @param ident points to objectname.0 (object id trailer)
+ * @param od points to object definition.
+ */
+static void
+system_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od)
+{
+  u8_t id;
+
+  /* return to object name, adding index depth (1) */
+  ident_len += 1;
+  ident -= 1;
+  if (ident_len == 2)
+  {
+    od->id_inst_len = ident_len;
+    od->id_inst_ptr = ident;
+
+    LWIP_ASSERT("invalid id", (ident[0] >= 0) && (ident[0] <= 0xff));
+    id = (u8_t)ident[0];
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("get_object_def system.%"U16_F".0\n",(u16_t)id));
+    switch (id)
+    {
+      case 1: /* sysDescr */
+        od->instance = MIB_OBJECT_SCALAR;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR);
+        od->v_len = *sysdescr_len_ptr;
+        break;
+      case 2: /* sysObjectID */
+        od->instance = MIB_OBJECT_SCALAR;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OBJ_ID);
+        od->v_len = sysobjid.len * sizeof(s32_t);
+        break;
+      case 3: /* sysUpTime */
+        od->instance = MIB_OBJECT_SCALAR;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_TIMETICKS);
+        od->v_len = sizeof(u32_t);
+        break;
+      case 4: /* sysContact */
+        od->instance = MIB_OBJECT_SCALAR;
+        od->access = MIB_OBJECT_READ_WRITE;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR);
+        od->v_len = *syscontact_len_ptr;
+        break;
+      case 5: /* sysName */
+        od->instance = MIB_OBJECT_SCALAR;
+        od->access = MIB_OBJECT_READ_WRITE;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR);
+        od->v_len = *sysname_len_ptr;
+        break;
+      case 6: /* sysLocation */
+        od->instance = MIB_OBJECT_SCALAR;
+        od->access = MIB_OBJECT_READ_WRITE;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR);
+        od->v_len = *syslocation_len_ptr;
+        break;
+      case 7: /* sysServices */
+        od->instance = MIB_OBJECT_SCALAR;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG);
+        od->v_len = sizeof(s32_t);
+        break;
+      default:
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("system_get_object_def: no such object\n"));
+        od->instance = MIB_OBJECT_NONE;
+        break;
+    };
+  }
+  else
+  {
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("system_get_object_def: no scalar\n"));
+    od->instance = MIB_OBJECT_NONE;
+  }
+}
+
+/**
+ * Returns system object value.
+ *
+ * @param ident_len the address length (2)
+ * @param ident points to objectname.0 (object id trailer)
+ * @param len return value space (in bytes)
+ * @param value points to (varbind) space to copy value into.
+ */
+static void
+system_get_value(struct obj_def *od, u16_t len, void *value)
+{
+  u8_t id;
+
+  LWIP_ASSERT("invalid id", (od->id_inst_ptr[0] >= 0) && (od->id_inst_ptr[0] <= 0xff));
+  id = (u8_t)od->id_inst_ptr[0];
+  switch (id)
+  {
+    case 1: /* sysDescr */
+      ocstrncpy((u8_t*)value, sysdescr_ptr, len);
+      break;
+    case 2: /* sysObjectID */
+      objectidncpy((s32_t*)value, (s32_t*)sysobjid.id, (u8_t)(len / sizeof(s32_t)));
+      break;
+    case 3: /* sysUpTime */
+      {
+        snmp_get_sysuptime((u32_t*)value);
+      }
+      break;
+    case 4: /* sysContact */
+      ocstrncpy((u8_t*)value, syscontact_ptr, len);
+      break;
+    case 5: /* sysName */
+      ocstrncpy((u8_t*)value, sysname_ptr, len);
+      break;
+    case 6: /* sysLocation */
+      ocstrncpy((u8_t*)value, syslocation_ptr, len);
+      break;
+    case 7: /* sysServices */
+      {
+        s32_t *sint_ptr = (s32_t*)value;
+        *sint_ptr = sysservices;
+      }
+      break;
+  };
+}
+
+static u8_t
+system_set_test(struct obj_def *od, u16_t len, void *value)
+{
+  u8_t id, set_ok;
+
+  LWIP_UNUSED_ARG(value);
+  set_ok = 0;
+  LWIP_ASSERT("invalid id", (od->id_inst_ptr[0] >= 0) && (od->id_inst_ptr[0] <= 0xff));
+  id = (u8_t)od->id_inst_ptr[0];
+  switch (id)
+  {
+    case 4: /* sysContact */
+      if ((syscontact_ptr != syscontact_default) &&
+          (len <= 255))
+      {
+        set_ok = 1;
+      }
+      break;
+    case 5: /* sysName */
+      if ((sysname_ptr != sysname_default) &&
+          (len <= 255))
+      {
+        set_ok = 1;
+      }
+      break;
+    case 6: /* sysLocation */
+      if ((syslocation_ptr != syslocation_default) &&
+          (len <= 255))
+      {
+        set_ok = 1;
+      }
+      break;
+  };
+  return set_ok;
+}
+
+static void
+system_set_value(struct obj_def *od, u16_t len, void *value)
+{
+  u8_t id;
+
+  LWIP_ASSERT("invalid len", len <= 0xff);
+  LWIP_ASSERT("invalid id", (od->id_inst_ptr[0] >= 0) && (od->id_inst_ptr[0] <= 0xff));
+  id = (u8_t)od->id_inst_ptr[0];
+  switch (id)
+  {
+    case 4: /* sysContact */
+      ocstrncpy(syscontact_ptr, (u8_t*)value, len);
+      *syscontact_len_ptr = (u8_t)len;
+      break;
+    case 5: /* sysName */
+      ocstrncpy(sysname_ptr, (u8_t*)value, len);
+      *sysname_len_ptr = (u8_t)len;
+      break;
+    case 6: /* sysLocation */
+      ocstrncpy(syslocation_ptr, (u8_t*)value, len);
+      *syslocation_len_ptr = (u8_t)len;
+      break;
+  };
+}
+
+/**
+ * Returns interfaces.ifnumber object definition.
+ *
+ * @param ident_len the address length (2)
+ * @param ident points to objectname.index
+ * @param od points to object definition.
+ */
+static void
+interfaces_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od)
+{
+  /* return to object name, adding index depth (1) */
+  ident_len += 1;
+  ident -= 1;
+  if (ident_len == 2)
+  {
+    od->id_inst_len = ident_len;
+    od->id_inst_ptr = ident;
+
+    od->instance = MIB_OBJECT_SCALAR;
+    od->access = MIB_OBJECT_READ_ONLY;
+    od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG);
+    od->v_len = sizeof(s32_t);
+  }
+  else
+  {
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("interfaces_get_object_def: no scalar\n"));
+    od->instance = MIB_OBJECT_NONE;
+  }
+}
+
+/**
+ * Returns interfaces.ifnumber object value.
+ *
+ * @param ident_len the address length (2)
+ * @param ident points to objectname.0 (object id trailer)
+ * @param len return value space (in bytes)
+ * @param value points to (varbind) space to copy value into.
+ */
+static void
+interfaces_get_value(struct obj_def *od, u16_t len, void *value)
+{
+  LWIP_UNUSED_ARG(len);
+  if (od->id_inst_ptr[0] == 1)
+  {
+    s32_t *sint_ptr = (s32_t*)value;
+    *sint_ptr = iflist_root.count;
+  }
+}
+
+/**
+ * Returns ifentry object definitions.
+ *
+ * @param ident_len the address length (2)
+ * @param ident points to objectname.index
+ * @param od points to object definition.
+ */
+static void
+ifentry_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od)
+{
+  u8_t id;
+
+  /* return to object name, adding index depth (1) */
+  ident_len += 1;
+  ident -= 1;
+  if (ident_len == 2)
+  {
+    od->id_inst_len = ident_len;
+    od->id_inst_ptr = ident;
+
+    LWIP_ASSERT("invalid id", (ident[0] >= 0) && (ident[0] <= 0xff));
+    id = (u8_t)ident[0];
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("get_object_def ifentry.%"U16_F"\n",(u16_t)id));
+    switch (id)
+    {
+      case 1: /* ifIndex */
+      case 3: /* ifType */
+      case 4: /* ifMtu */
+      case 8: /* ifOperStatus */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG);
+        od->v_len = sizeof(s32_t);
+        break;
+      case 2: /* ifDescr */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR);
+        /** @todo this should be some sort of sizeof(struct netif.name) */
+        od->v_len = 2;
+        break;
+      case 5: /* ifSpeed */
+      case 21: /* ifOutQLen */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_GAUGE);
+        od->v_len = sizeof(u32_t);
+        break;
+      case 6: /* ifPhysAddress */
+        {
+          struct netif *netif;
+
+          snmp_ifindextonetif(ident[1], &netif);
+          od->instance = MIB_OBJECT_TAB;
+          od->access = MIB_OBJECT_READ_ONLY;
+          od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR);
+          od->v_len = netif->hwaddr_len;
+        }
+        break;
+      case 7: /* ifAdminStatus */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_WRITE;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG);
+        od->v_len = sizeof(s32_t);
+        break;
+      case 9: /* ifLastChange */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_TIMETICKS);
+        od->v_len = sizeof(u32_t);
+        break;
+      case 10: /* ifInOctets */
+      case 11: /* ifInUcastPkts */
+      case 12: /* ifInNUcastPkts */
+      case 13: /* ifInDiscarts */
+      case 14: /* ifInErrors */
+      case 15: /* ifInUnkownProtos */
+      case 16: /* ifOutOctets */
+      case 17: /* ifOutUcastPkts */
+      case 18: /* ifOutNUcastPkts */
+      case 19: /* ifOutDiscarts */
+      case 20: /* ifOutErrors */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_COUNTER);
+        od->v_len = sizeof(u32_t);
+        break;
+      case 22: /* ifSpecific */
+        /** @note returning zeroDotZero (0.0) no media specific MIB support */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OBJ_ID);
+        od->v_len = ifspecific.len * sizeof(s32_t);
+        break;
+      default:
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("ifentry_get_object_def: no such object\n"));
+        od->instance = MIB_OBJECT_NONE;
+        break;
+    };
+  }
+  else
+  {
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("ifentry_get_object_def: no scalar\n"));
+    od->instance = MIB_OBJECT_NONE;
+  }
+}
+
+/**
+ * Returns ifentry object value.
+ *
+ * @param ident_len the address length (2)
+ * @param ident points to objectname.0 (object id trailer)
+ * @param len return value space (in bytes)
+ * @param value points to (varbind) space to copy value into.
+ */
+static void
+ifentry_get_value(struct obj_def *od, u16_t len, void *value)
+{
+  struct netif *netif;
+  u8_t id;
+
+  snmp_ifindextonetif(od->id_inst_ptr[1], &netif);
+  LWIP_ASSERT("invalid id", (od->id_inst_ptr[0] >= 0) && (od->id_inst_ptr[0] <= 0xff));
+  id = (u8_t)od->id_inst_ptr[0];
+  switch (id)
+  {
+    case 1: /* ifIndex */
+      {
+        s32_t *sint_ptr = (s32_t*)value;
+        *sint_ptr = od->id_inst_ptr[1];
+      }
+      break;
+    case 2: /* ifDescr */
+      ocstrncpy((u8_t*)value, (u8_t*)netif->name, len);
+      break;
+    case 3: /* ifType */
+      {
+        s32_t *sint_ptr = (s32_t*)value;
+        *sint_ptr = netif->link_type;
+      }
+      break;
+    case 4: /* ifMtu */
+      {
+        s32_t *sint_ptr = (s32_t*)value;
+        *sint_ptr = netif->mtu;
+      }
+      break;
+    case 5: /* ifSpeed */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = netif->link_speed;
+      }
+      break;
+    case 6: /* ifPhysAddress */
+      ocstrncpy((u8_t*)value, netif->hwaddr, len);
+      break;
+    case 7: /* ifAdminStatus */
+      {
+        s32_t *sint_ptr = (s32_t*)value;
+        if (netif_is_up(netif))
+        {
+          if (netif_is_link_up(netif))
+          {
+            *sint_ptr = 1; /* up */
+          }
+          else
+          {
+            *sint_ptr = 7; /* lowerLayerDown */
+          }
+        }
+        else
+        {
+          *sint_ptr = 2; /* down */
+        }
+      }
+      break;
+    case 8: /* ifOperStatus */
+      {
+        s32_t *sint_ptr = (s32_t*)value;
+        if (netif_is_up(netif))
+        {
+          *sint_ptr = 1;
+        }
+        else
+        {
+          *sint_ptr = 2;
+        }
+      }
+      break;
+    case 9: /* ifLastChange */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = netif->ts;
+      }
+      break;
+    case 10: /* ifInOctets */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = netif->ifinoctets;
+      }
+      break;
+    case 11: /* ifInUcastPkts */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = netif->ifinucastpkts;
+      }
+      break;
+    case 12: /* ifInNUcastPkts */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = netif->ifinnucastpkts;
+      }
+      break;
+    case 13: /* ifInDiscarts */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = netif->ifindiscards;
+      }
+      break;
+    case 14: /* ifInErrors */
+    case 15: /* ifInUnkownProtos */
+      /** @todo add these counters! */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = 0;
+      }
+      break;
+    case 16: /* ifOutOctets */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = netif->ifoutoctets;
+      }
+      break;
+    case 17: /* ifOutUcastPkts */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = netif->ifoutucastpkts;
+      }
+      break;
+    case 18: /* ifOutNUcastPkts */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = netif->ifoutnucastpkts;
+      }
+      break;
+    case 19: /* ifOutDiscarts */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = netif->ifoutdiscards;
+      }
+      break;
+    case 20: /* ifOutErrors */
+       /** @todo add this counter! */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = 0;
+      }
+      break;
+    case 21: /* ifOutQLen */
+      /** @todo figure out if this must be 0 (no queue) or 1? */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = 0;
+      }
+      break;
+    case 22: /* ifSpecific */
+      objectidncpy((s32_t*)value, (s32_t*)ifspecific.id, (u8_t)(len / sizeof(s32_t)));
+      break;
+  };
+}
+
+#if !SNMP_SAFE_REQUESTS
+static u8_t
+ifentry_set_test(struct obj_def *od, u16_t len, void *value)
+{
+  struct netif *netif;
+  u8_t id, set_ok;
+  LWIP_UNUSED_ARG(len);
+
+  set_ok = 0;
+  snmp_ifindextonetif(od->id_inst_ptr[1], &netif);
+  id = (u8_t)od->id_inst_ptr[0];
+  switch (id)
+  {
+    case 7: /* ifAdminStatus */
+      {
+        s32_t *sint_ptr = (s32_t*)value;
+        if (*sint_ptr == 1 || *sint_ptr == 2)
+          set_ok = 1;
+      }
+      break;
+  }
+  return set_ok;
+}
+
+static void
+ifentry_set_value(struct obj_def *od, u16_t len, void *value)
+{
+  struct netif *netif;
+  u8_t id;
+  LWIP_UNUSED_ARG(len);
+
+  snmp_ifindextonetif(od->id_inst_ptr[1], &netif);
+  id = (u8_t)od->id_inst_ptr[0];
+  switch (id)
+  {
+    case 7: /* ifAdminStatus */
+      {
+        s32_t *sint_ptr = (s32_t*)value;
+        if (*sint_ptr == 1)
+        {
+          netif_set_up(netif);
+        }
+        else if (*sint_ptr == 2)
+        {
+          netif_set_down(netif);
+         }
+      }
+      break;
+  }
+}
+#endif /* SNMP_SAFE_REQUESTS */
+
+/**
+ * Returns atentry object definitions.
+ *
+ * @param ident_len the address length (6)
+ * @param ident points to objectname.atifindex.atnetaddress
+ * @param od points to object definition.
+ */
+static void
+atentry_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od)
+{
+  /* return to object name, adding index depth (5) */
+  ident_len += 5;
+  ident -= 5;
+
+  if (ident_len == 6)
+  {
+    od->id_inst_len = ident_len;
+    od->id_inst_ptr = ident;
+
+    switch (ident[0])
+    {
+      case 1: /* atIfIndex */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_WRITE;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG);
+        od->v_len = sizeof(s32_t);
+        break;
+      case 2: /* atPhysAddress */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_WRITE;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR);
+        od->v_len = 6; /** @todo try to use netif::hwaddr_len */
+        break;
+      case 3: /* atNetAddress */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_WRITE;
+        od->asn_type = (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_IPADDR);
+        od->v_len = 4;
+        break;
+      default:
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("atentry_get_object_def: no such object\n"));
+        od->instance = MIB_OBJECT_NONE;
+        break;
+    }
+  }
+  else
+  {
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("atentry_get_object_def: no scalar\n"));
+    od->instance = MIB_OBJECT_NONE;
+  }
+}
+
+static void
+atentry_get_value(struct obj_def *od, u16_t len, void *value)
+{
+#if LWIP_ARP
+  u8_t id;
+  struct eth_addr* ethaddr_ret;
+  ip_addr_t* ipaddr_ret;
+#endif /* LWIP_ARP */
+  ip_addr_t ip;
+  struct netif *netif;
+
+  LWIP_UNUSED_ARG(len);
+  LWIP_UNUSED_ARG(value);/* if !LWIP_ARP */
+
+  snmp_ifindextonetif(od->id_inst_ptr[1], &netif);
+  snmp_oidtoip(&od->id_inst_ptr[2], &ip);
+
+#if LWIP_ARP /** @todo implement a netif_find_addr */
+  if (etharp_find_addr(netif, &ip, &ethaddr_ret, &ipaddr_ret) > -1)
+  {
+    LWIP_ASSERT("invalid id", (od->id_inst_ptr[0] >= 0) && (od->id_inst_ptr[0] <= 0xff));
+    id = (u8_t)od->id_inst_ptr[0];
+    switch (id)
+    {
+      case 1: /* atIfIndex */
+        {
+          s32_t *sint_ptr = (s32_t*)value;
+          *sint_ptr = od->id_inst_ptr[1];
+        }
+        break;
+      case 2: /* atPhysAddress */
+        {
+          struct eth_addr *dst = (struct eth_addr*)value;
+
+          *dst = *ethaddr_ret;
+        }
+        break;
+      case 3: /* atNetAddress */
+        {
+          ip_addr_t *dst = (ip_addr_t*)value;
+
+          *dst = *ipaddr_ret;
+        }
+        break;
+    }
+  }
+#endif /* LWIP_ARP */
+}
+
+static void
+ip_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od)
+{
+  u8_t id;
+
+  /* return to object name, adding index depth (1) */
+  ident_len += 1;
+  ident -= 1;
+  if (ident_len == 2)
+  {
+    od->id_inst_len = ident_len;
+    od->id_inst_ptr = ident;
+
+    LWIP_ASSERT("invalid id", (ident[0] >= 0) && (ident[0] <= 0xff));
+    id = (u8_t)ident[0];
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("get_object_def ip.%"U16_F".0\n",(u16_t)id));
+    switch (id)
+    {
+      case 1: /* ipForwarding */
+      case 2: /* ipDefaultTTL */
+        od->instance = MIB_OBJECT_SCALAR;
+        od->access = MIB_OBJECT_READ_WRITE;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG);
+        od->v_len = sizeof(s32_t);
+        break;
+      case 3: /* ipInReceives */
+      case 4: /* ipInHdrErrors */
+      case 5: /* ipInAddrErrors */
+      case 6: /* ipForwDatagrams */
+      case 7: /* ipInUnknownProtos */
+      case 8: /* ipInDiscards */
+      case 9: /* ipInDelivers */
+      case 10: /* ipOutRequests */
+      case 11: /* ipOutDiscards */
+      case 12: /* ipOutNoRoutes */
+      case 14: /* ipReasmReqds */
+      case 15: /* ipReasmOKs */
+      case 16: /* ipReasmFails */
+      case 17: /* ipFragOKs */
+      case 18: /* ipFragFails */
+      case 19: /* ipFragCreates */
+      case 23: /* ipRoutingDiscards */
+        od->instance = MIB_OBJECT_SCALAR;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_COUNTER);
+        od->v_len = sizeof(u32_t);
+        break;
+      case 13: /* ipReasmTimeout */
+        od->instance = MIB_OBJECT_SCALAR;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG);
+        od->v_len = sizeof(s32_t);
+        break;
+      default:
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("ip_get_object_def: no such object\n"));
+        od->instance = MIB_OBJECT_NONE;
+        break;
+    };
+  }
+  else
+  {
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("ip_get_object_def: no scalar\n"));
+    od->instance = MIB_OBJECT_NONE;
+  }
+}
+
+static void
+ip_get_value(struct obj_def *od, u16_t len, void *value)
+{
+  u8_t id;
+
+  LWIP_UNUSED_ARG(len);
+  LWIP_ASSERT("invalid id", (od->id_inst_ptr[0] >= 0) && (od->id_inst_ptr[0] <= 0xff));
+  id = (u8_t)od->id_inst_ptr[0];
+  switch (id)
+  {
+    case 1: /* ipForwarding */
+      {
+        s32_t *sint_ptr = (s32_t*)value;
+#if IP_FORWARD
+        /* forwarding */
+        *sint_ptr = 1;
+#else
+        /* not-forwarding */
+        *sint_ptr = 2;
+#endif
+      }
+      break;
+    case 2: /* ipDefaultTTL */
+      {
+        s32_t *sint_ptr = (s32_t*)value;
+        *sint_ptr = IP_DEFAULT_TTL;
+      }
+      break;
+    case 3: /* ipInReceives */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = ipinreceives;
+      }
+      break;
+    case 4: /* ipInHdrErrors */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = ipinhdrerrors;
+      }
+      break;
+    case 5: /* ipInAddrErrors */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = ipinaddrerrors;
+      }
+      break;
+    case 6: /* ipForwDatagrams */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = ipforwdatagrams;
+      }
+      break;
+    case 7: /* ipInUnknownProtos */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = ipinunknownprotos;
+      }
+      break;
+    case 8: /* ipInDiscards */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = ipindiscards;
+      }
+      break;
+    case 9: /* ipInDelivers */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = ipindelivers;
+      }
+      break;
+    case 10: /* ipOutRequests */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = ipoutrequests;
+      }
+      break;
+    case 11: /* ipOutDiscards */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = ipoutdiscards;
+      }
+      break;
+    case 12: /* ipOutNoRoutes */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = ipoutnoroutes;
+      }
+      break;
+    case 13: /* ipReasmTimeout */
+      {
+        s32_t *sint_ptr = (s32_t*)value;
+#if IP_REASSEMBLY
+        *sint_ptr = IP_REASS_MAXAGE;
+#else
+        *sint_ptr = 0;
+#endif
+      }
+      break;
+    case 14: /* ipReasmReqds */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = ipreasmreqds;
+      }
+      break;
+    case 15: /* ipReasmOKs */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = ipreasmoks;
+      }
+      break;
+    case 16: /* ipReasmFails */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = ipreasmfails;
+      }
+      break;
+    case 17: /* ipFragOKs */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = ipfragoks;
+      }
+      break;
+    case 18: /* ipFragFails */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = ipfragfails;
+      }
+      break;
+    case 19: /* ipFragCreates */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = ipfragcreates;
+      }
+      break;
+    case 23: /* ipRoutingDiscards */
+      /** @todo can lwIP discard routes at all?? hardwire this to 0?? */
+      {
+        u32_t *uint_ptr = (u32_t*)value;
+        *uint_ptr = iproutingdiscards;
+      }
+      break;
+  };
+}
+
+/**
+ * Test ip object value before setting.
+ *
+ * @param od is the object definition
+ * @param len return value space (in bytes)
+ * @param value points to (varbind) space to copy value from.
+ *
+ * @note we allow set if the value matches the hardwired value,
+ *   otherwise return badvalue.
+ */
+static u8_t
+ip_set_test(struct obj_def *od, u16_t len, void *value)
+{
+  u8_t id, set_ok;
+  s32_t *sint_ptr = (s32_t*)value;
+
+  LWIP_UNUSED_ARG(len);
+  set_ok = 0;
+  LWIP_ASSERT("invalid id", (od->id_inst_ptr[0] >= 0) && (od->id_inst_ptr[0] <= 0xff));
+  id = (u8_t)od->id_inst_ptr[0];
+  switch (id)
+  {
+    case 1: /* ipForwarding */
+#if IP_FORWARD
+      /* forwarding */
+      if (*sint_ptr == 1)
+#else
+      /* not-forwarding */
+      if (*sint_ptr == 2)
+#endif
+      {
+        set_ok = 1;
+      }
+      break;
+    case 2: /* ipDefaultTTL */
+      if (*sint_ptr == IP_DEFAULT_TTL)
+      {
+        set_ok = 1;
+      }
+      break;
+  };
+  return set_ok;
+}
+
+static void
+ip_addrentry_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od)
+{
+  /* return to object name, adding index depth (4) */
+  ident_len += 4;
+  ident -= 4;
+
+  if (ident_len == 5)
+  {
+    u8_t id;
+
+    od->id_inst_len = ident_len;
+    od->id_inst_ptr = ident;
+
+    LWIP_ASSERT("invalid id", (ident[0] >= 0) && (ident[0] <= 0xff));
+    id = (u8_t)ident[0];
+    switch (id)
+    {
+      case 1: /* ipAdEntAddr */
+      case 3: /* ipAdEntNetMask */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_IPADDR);
+        od->v_len = 4;
+        break;
+      case 2: /* ipAdEntIfIndex */
+      case 4: /* ipAdEntBcastAddr */
+      case 5: /* ipAdEntReasmMaxSize */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG);
+        od->v_len = sizeof(s32_t);
+        break;
+      default:
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("ip_addrentry_get_object_def: no such object\n"));
+        od->instance = MIB_OBJECT_NONE;
+        break;
+    }
+  }
+  else
+  {
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("ip_addrentry_get_object_def: no scalar\n"));
+    od->instance = MIB_OBJECT_NONE;
+  }
+}
+
+static void
+ip_addrentry_get_value(struct obj_def *od, u16_t len, void *value)
+{
+  u8_t id;
+  u16_t ifidx;
+  ip_addr_t ip;
+  struct netif *netif = netif_list;
+
+  LWIP_UNUSED_ARG(len);
+  snmp_oidtoip(&od->id_inst_ptr[1], &ip);
+  ifidx = 0;
+  while ((netif != NULL) && !ip_addr_cmp(&ip, &netif->ip_addr))
+  {
+    netif = netif->next;
+    ifidx++;
+  }
+
+  if (netif != NULL)
+  {
+    LWIP_ASSERT("invalid id", (od->id_inst_ptr[0] >= 0) && (od->id_inst_ptr[0] <= 0xff));
+    id = (u8_t)od->id_inst_ptr[0];
+    switch (id)
+    {
+      case 1: /* ipAdEntAddr */
+        {
+          ip_addr_t *dst = (ip_addr_t*)value;
+          *dst = netif->ip_addr;
+        }
+        break;
+      case 2: /* ipAdEntIfIndex */
+        {
+          s32_t *sint_ptr = (s32_t*)value;
+          *sint_ptr = ifidx + 1;
+        }
+        break;
+      case 3: /* ipAdEntNetMask */
+        {
+          ip_addr_t *dst = (ip_addr_t*)value;
+          *dst = netif->netmask;
+        }
+        break;
+      case 4: /* ipAdEntBcastAddr */
+        {
+          s32_t *sint_ptr = (s32_t*)value;
+
+          /* lwIP oddity, there's no broadcast
+            address in the netif we can rely on */
+          *sint_ptr = IPADDR_BROADCAST & 1;
+        }
+        break;
+      case 5: /* ipAdEntReasmMaxSize */
+        {
+          s32_t *sint_ptr = (s32_t*)value;
+#if IP_REASSEMBLY
+          /* @todo The theoretical maximum is IP_REASS_MAX_PBUFS * size of the pbufs,
+           * but only if receiving one fragmented packet at a time.
+           * The current solution is to calculate for 2 simultaneous packets...
+           */
+          *sint_ptr = (IP_HLEN + ((IP_REASS_MAX_PBUFS/2) *
+            (PBUF_POOL_BUFSIZE - PBUF_LINK_HLEN - IP_HLEN)));
+#else
+          /** @todo returning MTU would be a bad thing and
+             returning a wild guess like '576' isn't good either */
+          *sint_ptr = 0;
+#endif
+        }
+        break;
+    }
+  }
+}
+
+/**
+ * @note
+ * lwIP IP routing is currently using the network addresses in netif_list.
+ * if no suitable network IP is found in netif_list, the default_netif is used.
+ */
+static void
+ip_rteentry_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od)
+{
+  u8_t id;
+
+  /* return to object name, adding index depth (4) */
+  ident_len += 4;
+  ident -= 4;
+
+  if (ident_len == 5)
+  {
+    od->id_inst_len = ident_len;
+    od->id_inst_ptr = ident;
+
+    LWIP_ASSERT("invalid id", (ident[0] >= 0) && (ident[0] <= 0xff));
+    id = (u8_t)ident[0];
+    switch (id)
+    {
+      case 1: /* ipRouteDest */
+      case 7: /* ipRouteNextHop */
+      case 11: /* ipRouteMask */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_WRITE;
+        od->asn_type = (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_IPADDR);
+        od->v_len = 4;
+        break;
+      case 2: /* ipRouteIfIndex */
+      case 3: /* ipRouteMetric1 */
+      case 4: /* ipRouteMetric2 */
+      case 5: /* ipRouteMetric3 */
+      case 6: /* ipRouteMetric4 */
+      case 8: /* ipRouteType */
+      case 10: /* ipRouteAge */
+      case 12: /* ipRouteMetric5 */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_WRITE;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG);
+        od->v_len = sizeof(s32_t);
+        break;
+      case 9: /* ipRouteProto */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG);
+        od->v_len = sizeof(s32_t);
+        break;
+      case 13: /* ipRouteInfo */
+        /** @note returning zeroDotZero (0.0) no routing protocol specific MIB */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OBJ_ID);
+        od->v_len = iprouteinfo.len * sizeof(s32_t);
+        break;
+      default:
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("ip_rteentry_get_object_def: no such object\n"));
+        od->instance = MIB_OBJECT_NONE;
+        break;
+    }
+  }
+  else
+  {
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("ip_rteentry_get_object_def: no scalar\n"));
+    od->instance = MIB_OBJECT_NONE;
+  }
+}
+
+static void
+ip_rteentry_get_value(struct obj_def *od, u16_t len, void *value)
+{
+  struct netif *netif;
+  ip_addr_t dest;
+  s32_t *ident;
+  u8_t id;
+
+  ident = od->id_inst_ptr;
+  snmp_oidtoip(&ident[1], &dest);
+
+  if (ip_addr_isany(&dest))
+  {
+    /* ip_route() uses default netif for default route */
+    netif = netif_default;
+  }
+  else
+  {
+    /* not using ip_route(), need exact match! */
+    netif = netif_list;
+    while ((netif != NULL) &&
+            !ip_addr_netcmp(&dest, &(netif->ip_addr), &(netif->netmask)) )
+    {
+      netif = netif->next;
+    }
+  }
+  if (netif != NULL)
+  {
+    LWIP_ASSERT("invalid id", (ident[0] >= 0) && (ident[0] <= 0xff));
+    id = (u8_t)ident[0];
+    switch (id)
+    {
+      case 1: /* ipRouteDest */
+        {
+          ip_addr_t *dst = (ip_addr_t*)value;
+
+          if (ip_addr_isany(&dest))
+          {
+            /* default rte has 0.0.0.0 dest */
+            ip_addr_set_zero(dst);
+          }
+          else
+          {
+            /* netifs have netaddress dest */
+            ip_addr_get_network(dst, &netif->ip_addr, &netif->netmask);
+          }
+        }
+        break;
+      case 2: /* ipRouteIfIndex */
+        {
+          s32_t *sint_ptr = (s32_t*)value;
+
+          snmp_netiftoifindex(netif, sint_ptr);
+        }
+        break;
+      case 3: /* ipRouteMetric1 */
+        {
+          s32_t *sint_ptr = (s32_t*)value;
+
+          if (ip_addr_isany(&dest))
+          {
+            /* default rte has metric 1 */
+            *sint_ptr = 1;
+          }
+          else
+          {
+            /* other rtes have metric 0 */
+            *sint_ptr = 0;
+          }
+        }
+        break;
+      case 4: /* ipRouteMetric2 */
+      case 5: /* ipRouteMetric3 */
+      case 6: /* ipRouteMetric4 */
+      case 12: /* ipRouteMetric5 */
+        {
+          s32_t *sint_ptr = (s32_t*)value;
+          /* not used */
+          *sint_ptr = -1;
+        }
+        break;
+      case 7: /* ipRouteNextHop */
+        {
+          ip_addr_t *dst = (ip_addr_t*)value;
+
+          if (ip_addr_isany(&dest))
+          {
+            /* default rte: gateway */
+            *dst = netif->gw;
+          }
+          else
+          {
+            /* other rtes: netif ip_addr  */
+            *dst = netif->ip_addr;
+          }
+        }
+        break;
+      case 8: /* ipRouteType */
+        {
+          s32_t *sint_ptr = (s32_t*)value;
+
+          if (ip_addr_isany(&dest))
+          {
+            /* default rte is indirect */
+            *sint_ptr = 4;
+          }
+          else
+          {
+            /* other rtes are direct */
+            *sint_ptr = 3;
+          }
+        }
+        break;
+      case 9: /* ipRouteProto */
+        {
+          s32_t *sint_ptr = (s32_t*)value;
+          /* locally defined routes */
+          *sint_ptr = 2;
+        }
+        break;
+      case 10: /* ipRouteAge */
+        {
+          s32_t *sint_ptr = (s32_t*)value;
+          /** @todo (sysuptime - timestamp last change) / 100
+              @see snmp_insert_iprteidx_tree() */
+          *sint_ptr = 0;
+        }
+        break;
+      case 11: /* ipRouteMask */
+        {
+          ip_addr_t *dst = (ip_addr_t*)value;
+
+          if (ip_addr_isany(&dest))
+          {
+            /* default rte use 0.0.0.0 mask */
+            ip_addr_set_zero(dst);
+          }
+          else
+          {
+            /* other rtes use netmask */
+            *dst = netif->netmask;
+          }
+        }
+        break;
+      case 13: /* ipRouteInfo */
+        objectidncpy((s32_t*)value, (s32_t*)iprouteinfo.id, (u8_t)(len / sizeof(s32_t)));
+        break;
+    }
+  }
+}
+
+static void
+ip_ntomentry_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od)
+{
+  /* return to object name, adding index depth (5) */
+  ident_len += 5;
+  ident -= 5;
+
+  if (ident_len == 6)
+  {
+    u8_t id;
+
+    od->id_inst_len = ident_len;
+    od->id_inst_ptr = ident;
+
+    LWIP_ASSERT("invalid id", (ident[0] >= 0) && (ident[0] <= 0xff));
+    id = (u8_t)ident[0];
+    switch (id)
+    {
+      case 1: /* ipNetToMediaIfIndex */
+      case 4: /* ipNetToMediaType */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_WRITE;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG);
+        od->v_len = sizeof(s32_t);
+        break;
+      case 2: /* ipNetToMediaPhysAddress */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_WRITE;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR);
+        od->v_len = 6; /** @todo try to use netif::hwaddr_len */
+        break;
+      case 3: /* ipNetToMediaNetAddress */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_WRITE;
+        od->asn_type = (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_IPADDR);
+        od->v_len = 4;
+        break;
+      default:
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("ip_ntomentry_get_object_def: no such object\n"));
+        od->instance = MIB_OBJECT_NONE;
+        break;
+    }
+  }
+  else
+  {
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("ip_ntomentry_get_object_def: no scalar\n"));
+    od->instance = MIB_OBJECT_NONE;
+  }
+}
+
+static void
+ip_ntomentry_get_value(struct obj_def *od, u16_t len, void *value)
+{
+#if LWIP_ARP
+  u8_t id;
+  struct eth_addr* ethaddr_ret;
+  ip_addr_t* ipaddr_ret;
+#endif /* LWIP_ARP */
+  ip_addr_t ip;
+  struct netif *netif;
+
+  LWIP_UNUSED_ARG(len);
+  LWIP_UNUSED_ARG(value);/* if !LWIP_ARP */
+
+  snmp_ifindextonetif(od->id_inst_ptr[1], &netif);
+  snmp_oidtoip(&od->id_inst_ptr[2], &ip);
+
+#if LWIP_ARP /** @todo implement a netif_find_addr */
+  if (etharp_find_addr(netif, &ip, &ethaddr_ret, &ipaddr_ret) > -1)
+  {
+    LWIP_ASSERT("invalid id", (od->id_inst_ptr[0] >= 0) && (od->id_inst_ptr[0] <= 0xff));
+    id = (u8_t)od->id_inst_ptr[0];
+    switch (id)
+    {
+      case 1: /* ipNetToMediaIfIndex */
+        {
+          s32_t *sint_ptr = (s32_t*)value;
+          *sint_ptr = od->id_inst_ptr[1];
+        }
+        break;
+      case 2: /* ipNetToMediaPhysAddress */
+        {
+          struct eth_addr *dst = (struct eth_addr*)value;
+
+          *dst = *ethaddr_ret;
+        }
+        break;
+      case 3: /* ipNetToMediaNetAddress */
+        {
+          ip_addr_t *dst = (ip_addr_t*)value;
+
+          *dst = *ipaddr_ret;
+        }
+        break;
+      case 4: /* ipNetToMediaType */
+        {
+          s32_t *sint_ptr = (s32_t*)value;
+          /* dynamic (?) */
+          *sint_ptr = 3;
+        }
+        break;
+    }
+  }
+#endif /* LWIP_ARP */
+}
+
+static void
+icmp_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od)
+{
+  /* return to object name, adding index depth (1) */
+  ident_len += 1;
+  ident -= 1;
+  if ((ident_len == 2) &&
+      (ident[0] > 0) && (ident[0] < 27))
+  {
+    od->id_inst_len = ident_len;
+    od->id_inst_ptr = ident;
+
+    od->instance = MIB_OBJECT_SCALAR;
+    od->access = MIB_OBJECT_READ_ONLY;
+    od->asn_type = (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_COUNTER);
+    od->v_len = sizeof(u32_t);
+  }
+  else
+  {
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("icmp_get_object_def: no scalar\n"));
+    od->instance = MIB_OBJECT_NONE;
+  }
+}
+
+static void
+icmp_get_value(struct obj_def *od, u16_t len, void *value)
+{
+  u32_t *uint_ptr = (u32_t*)value;
+  u8_t id;
+
+  LWIP_UNUSED_ARG(len);
+  LWIP_ASSERT("invalid id", (od->id_inst_ptr[0] >= 0) && (od->id_inst_ptr[0] <= 0xff));
+  id = (u8_t)od->id_inst_ptr[0];
+  switch (id)
+  {
+    case 1: /* icmpInMsgs */
+      *uint_ptr = icmpinmsgs;
+      break;
+    case 2: /* icmpInErrors */
+      *uint_ptr = icmpinerrors;
+      break;
+    case 3: /* icmpInDestUnreachs */
+      *uint_ptr = icmpindestunreachs;
+      break;
+    case 4: /* icmpInTimeExcds */
+      *uint_ptr = icmpintimeexcds;
+      break;
+    case 5: /* icmpInParmProbs */
+      *uint_ptr = icmpinparmprobs;
+      break;
+    case 6: /* icmpInSrcQuenchs */
+      *uint_ptr = icmpinsrcquenchs;
+      break;
+    case 7: /* icmpInRedirects */
+      *uint_ptr = icmpinredirects;
+      break;
+    case 8: /* icmpInEchos */
+      *uint_ptr = icmpinechos;
+      break;
+    case 9: /* icmpInEchoReps */
+      *uint_ptr = icmpinechoreps;
+      break;
+    case 10: /* icmpInTimestamps */
+      *uint_ptr = icmpintimestamps;
+      break;
+    case 11: /* icmpInTimestampReps */
+      *uint_ptr = icmpintimestampreps;
+      break;
+    case 12: /* icmpInAddrMasks */
+      *uint_ptr = icmpinaddrmasks;
+      break;
+    case 13: /* icmpInAddrMaskReps */
+      *uint_ptr = icmpinaddrmaskreps;
+      break;
+    case 14: /* icmpOutMsgs */
+      *uint_ptr = icmpoutmsgs;
+      break;
+    case 15: /* icmpOutErrors */
+      *uint_ptr = icmpouterrors;
+      break;
+    case 16: /* icmpOutDestUnreachs */
+      *uint_ptr = icmpoutdestunreachs;
+      break;
+    case 17: /* icmpOutTimeExcds */
+      *uint_ptr = icmpouttimeexcds;
+      break;
+    case 18: /* icmpOutParmProbs */
+      *uint_ptr = icmpoutparmprobs;
+      break;
+    case 19: /* icmpOutSrcQuenchs */
+      *uint_ptr = icmpoutsrcquenchs;
+      break;
+    case 20: /* icmpOutRedirects */
+      *uint_ptr = icmpoutredirects;
+      break;
+    case 21: /* icmpOutEchos */
+      *uint_ptr = icmpoutechos;
+      break;
+    case 22: /* icmpOutEchoReps */
+      *uint_ptr = icmpoutechoreps;
+      break;
+    case 23: /* icmpOutTimestamps */
+      *uint_ptr = icmpouttimestamps;
+      break;
+    case 24: /* icmpOutTimestampReps */
+      *uint_ptr = icmpouttimestampreps;
+      break;
+    case 25: /* icmpOutAddrMasks */
+      *uint_ptr = icmpoutaddrmasks;
+      break;
+    case 26: /* icmpOutAddrMaskReps */
+      *uint_ptr = icmpoutaddrmaskreps;
+      break;
+  }
+}
+
+#if LWIP_TCP
+/** @todo tcp grp */
+static void
+tcp_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od)
+{
+  u8_t id;
+
+  /* return to object name, adding index depth (1) */
+  ident_len += 1;
+  ident -= 1;
+  if (ident_len == 2)
+  {
+    od->id_inst_len = ident_len;
+    od->id_inst_ptr = ident;
+
+    LWIP_ASSERT("invalid id", (ident[0] >= 0) && (ident[0] <= 0xff));
+    id = (u8_t)ident[0];
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("get_object_def tcp.%"U16_F".0\n",(u16_t)id));
+
+    switch (id)
+    {
+      case 1: /* tcpRtoAlgorithm */
+      case 2: /* tcpRtoMin */
+      case 3: /* tcpRtoMax */
+      case 4: /* tcpMaxConn */
+        od->instance = MIB_OBJECT_SCALAR;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG);
+        od->v_len = sizeof(s32_t);
+        break;
+      case 5: /* tcpActiveOpens */
+      case 6: /* tcpPassiveOpens */
+      case 7: /* tcpAttemptFails */
+      case 8: /* tcpEstabResets */
+      case 10: /* tcpInSegs */
+      case 11: /* tcpOutSegs */
+      case 12: /* tcpRetransSegs */
+      case 14: /* tcpInErrs */
+      case 15: /* tcpOutRsts */
+        od->instance = MIB_OBJECT_SCALAR;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_COUNTER);
+        od->v_len = sizeof(u32_t);
+        break;
+      case 9: /* tcpCurrEstab */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_GAUGE);
+        od->v_len = sizeof(u32_t);
+        break;
+      default:
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("tcp_get_object_def: no such object\n"));
+        od->instance = MIB_OBJECT_NONE;
+        break;
+    };
+  }
+  else
+  {
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("tcp_get_object_def: no scalar\n"));
+    od->instance = MIB_OBJECT_NONE;
+  }
+}
+
+static void
+tcp_get_value(struct obj_def *od, u16_t len, void *value)
+{
+  u32_t *uint_ptr = (u32_t*)value;
+  s32_t *sint_ptr = (s32_t*)value;
+  u8_t id;
+
+  LWIP_UNUSED_ARG(len);
+  LWIP_ASSERT("invalid id", (od->id_inst_ptr[0] >= 0) && (od->id_inst_ptr[0] <= 0xff));
+  id = (u8_t)od->id_inst_ptr[0];
+  switch (id)
+  {
+    case 1: /* tcpRtoAlgorithm, vanj(4) */
+      *sint_ptr = 4;
+      break;
+    case 2: /* tcpRtoMin */
+      /* @todo not the actual value, a guess,
+          needs to be calculated */
+      *sint_ptr = 1000;
+      break;
+    case 3: /* tcpRtoMax */
+      /* @todo not the actual value, a guess,
+         needs to be calculated */
+      *sint_ptr = 60000;
+      break;
+    case 4: /* tcpMaxConn */
+      *sint_ptr = MEMP_NUM_TCP_PCB;
+      break;
+    case 5: /* tcpActiveOpens */
+      *uint_ptr = tcpactiveopens;
+      break;
+    case 6: /* tcpPassiveOpens */
+      *uint_ptr = tcppassiveopens;
+      break;
+    case 7: /* tcpAttemptFails */
+      *uint_ptr = tcpattemptfails;
+      break;
+    case 8: /* tcpEstabResets */
+      *uint_ptr = tcpestabresets;
+      break;
+    case 9: /* tcpCurrEstab */
+      {
+        u16_t tcpcurrestab = 0;
+        struct tcp_pcb *pcb = tcp_active_pcbs;
+        while (pcb != NULL)
+        {
+          if ((pcb->state == ESTABLISHED) ||
+              (pcb->state == CLOSE_WAIT))
+          {
+            tcpcurrestab++;
+          }
+          pcb = pcb->next;
+        }
+        *uint_ptr = tcpcurrestab;
+      }
+      break;
+    case 10: /* tcpInSegs */
+      *uint_ptr = tcpinsegs;
+      break;
+    case 11: /* tcpOutSegs */
+      *uint_ptr = tcpoutsegs;
+      break;
+    case 12: /* tcpRetransSegs */
+      *uint_ptr = tcpretranssegs;
+      break;
+    case 14: /* tcpInErrs */
+      *uint_ptr = tcpinerrs;
+      break;
+    case 15: /* tcpOutRsts */
+      *uint_ptr = tcpoutrsts;
+      break;
+  }
+}
+#ifdef THIS_SEEMS_UNUSED
+static void
+tcpconnentry_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od)
+{
+  /* return to object name, adding index depth (10) */
+  ident_len += 10;
+  ident -= 10;
+
+  if (ident_len == 11)
+  {
+    u8_t id;
+
+    od->id_inst_len = ident_len;
+    od->id_inst_ptr = ident;
+
+    id = ident[0];
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("get_object_def tcp.%"U16_F".0\n",(u16_t)id));
+
+    switch (id)
+    {
+      case 1: /* tcpConnState */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_WRITE;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG);
+        od->v_len = sizeof(s32_t);
+        break;
+      case 2: /* tcpConnLocalAddress */
+      case 4: /* tcpConnRemAddress */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_IPADDR);
+        od->v_len = 4;
+        break;
+      case 3: /* tcpConnLocalPort */
+      case 5: /* tcpConnRemPort */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG);
+        od->v_len = sizeof(s32_t);
+        break;
+      default:
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("tcpconnentry_get_object_def: no such object\n"));
+        od->instance = MIB_OBJECT_NONE;
+        break;
+    };
+  }
+  else
+  {
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("tcpconnentry_get_object_def: no such object\n"));
+    od->instance = MIB_OBJECT_NONE;
+  }
+}
+
+static void
+tcpconnentry_get_value(struct obj_def *od, u16_t len, void *value)
+{
+  ip_addr_t lip, rip;
+  u16_t lport, rport;
+  s32_t *ident;
+
+  ident = od->id_inst_ptr;
+  snmp_oidtoip(&ident[1], &lip);
+  lport = ident[5];
+  snmp_oidtoip(&ident[6], &rip);
+  rport = ident[10];
+
+  /** @todo find matching PCB */
+}
+#endif /* if 0 */
+#endif
+
+static void
+udp_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od)
+{
+  /* return to object name, adding index depth (1) */
+  ident_len += 1;
+  ident -= 1;
+  if ((ident_len == 2) &&
+      (ident[0] > 0) && (ident[0] < 6))
+  {
+    od->id_inst_len = ident_len;
+    od->id_inst_ptr = ident;
+
+    od->instance = MIB_OBJECT_SCALAR;
+    od->access = MIB_OBJECT_READ_ONLY;
+    od->asn_type = (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_COUNTER);
+    od->v_len = sizeof(u32_t);
+  }
+  else
+  {
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("udp_get_object_def: no scalar\n"));
+    od->instance = MIB_OBJECT_NONE;
+  }
+}
+
+static void
+udp_get_value(struct obj_def *od, u16_t len, void *value)
+{
+  u32_t *uint_ptr = (u32_t*)value;
+  u8_t id;
+
+  LWIP_UNUSED_ARG(len);
+  LWIP_ASSERT("invalid id", (od->id_inst_ptr[0] >= 0) && (od->id_inst_ptr[0] <= 0xff));
+  id = (u8_t)od->id_inst_ptr[0];
+  switch (id)
+  {
+    case 1: /* udpInDatagrams */
+      *uint_ptr = udpindatagrams;
+      break;
+    case 2: /* udpNoPorts */
+      *uint_ptr = udpnoports;
+      break;
+    case 3: /* udpInErrors */
+      *uint_ptr = udpinerrors;
+      break;
+    case 4: /* udpOutDatagrams */
+      *uint_ptr = udpoutdatagrams;
+      break;
+  }
+}
+
+static void
+udpentry_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od)
+{
+  /* return to object name, adding index depth (5) */
+  ident_len += 5;
+  ident -= 5;
+
+  if (ident_len == 6)
+  {
+    od->id_inst_len = ident_len;
+    od->id_inst_ptr = ident;
+
+    switch (ident[0])
+    {
+      case 1: /* udpLocalAddress */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_IPADDR);
+        od->v_len = 4;
+        break;
+      case 2: /* udpLocalPort */
+        od->instance = MIB_OBJECT_TAB;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG);
+        od->v_len = sizeof(s32_t);
+        break;
+      default:
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("udpentry_get_object_def: no such object\n"));
+        od->instance = MIB_OBJECT_NONE;
+        break;
+    }
+  }
+  else
+  {
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("udpentry_get_object_def: no scalar\n"));
+    od->instance = MIB_OBJECT_NONE;
+  }
+}
+
+static void
+udpentry_get_value(struct obj_def *od, u16_t len, void *value)
+{
+  u8_t id;
+  struct udp_pcb *pcb;
+  ip_addr_t ip;
+  u16_t port;
+
+  LWIP_UNUSED_ARG(len);
+  snmp_oidtoip(&od->id_inst_ptr[1], &ip);
+  LWIP_ASSERT("invalid port", (od->id_inst_ptr[5] >= 0) && (od->id_inst_ptr[5] <= 0xffff));
+  port = (u16_t)od->id_inst_ptr[5];
+
+  pcb = udp_pcbs;
+  while ((pcb != NULL) &&
+         !(ip_addr_cmp(&pcb->local_ip, &ip) &&
+           (pcb->local_port == port)))
+  {
+    pcb = pcb->next;
+  }
+
+  if (pcb != NULL)
+  {
+    LWIP_ASSERT("invalid id", (od->id_inst_ptr[0] >= 0) && (od->id_inst_ptr[0] <= 0xff));
+    id = (u8_t)od->id_inst_ptr[0];
+    switch (id)
+    {
+      case 1: /* udpLocalAddress */
+        {
+          ip_addr_t *dst = (ip_addr_t*)value;
+          *dst = pcb->local_ip;
+        }
+        break;
+      case 2: /* udpLocalPort */
+        {
+          s32_t *sint_ptr = (s32_t*)value;
+          *sint_ptr = pcb->local_port;
+        }
+        break;
+    }
+  }
+}
+
+static void
+snmp_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od)
+{
+  /* return to object name, adding index depth (1) */
+  ident_len += 1;
+  ident -= 1;
+  if (ident_len == 2)
+  {
+    u8_t id;
+
+    od->id_inst_len = ident_len;
+    od->id_inst_ptr = ident;
+
+    LWIP_ASSERT("invalid id", (ident[0] >= 0) && (ident[0] <= 0xff));
+    id = (u8_t)ident[0];
+    switch (id)
+    {
+      case 1: /* snmpInPkts */
+      case 2: /* snmpOutPkts */
+      case 3: /* snmpInBadVersions */
+      case 4: /* snmpInBadCommunityNames */
+      case 5: /* snmpInBadCommunityUses */
+      case 6: /* snmpInASNParseErrs */
+      case 8: /* snmpInTooBigs */
+      case 9: /* snmpInNoSuchNames */
+      case 10: /* snmpInBadValues */
+      case 11: /* snmpInReadOnlys */
+      case 12: /* snmpInGenErrs */
+      case 13: /* snmpInTotalReqVars */
+      case 14: /* snmpInTotalSetVars */
+      case 15: /* snmpInGetRequests */
+      case 16: /* snmpInGetNexts */
+      case 17: /* snmpInSetRequests */
+      case 18: /* snmpInGetResponses */
+      case 19: /* snmpInTraps */
+      case 20: /* snmpOutTooBigs */
+      case 21: /* snmpOutNoSuchNames */
+      case 22: /* snmpOutBadValues */
+      case 24: /* snmpOutGenErrs */
+      case 25: /* snmpOutGetRequests */
+      case 26: /* snmpOutGetNexts */
+      case 27: /* snmpOutSetRequests */
+      case 28: /* snmpOutGetResponses */
+      case 29: /* snmpOutTraps */
+        od->instance = MIB_OBJECT_SCALAR;
+        od->access = MIB_OBJECT_READ_ONLY;
+        od->asn_type = (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_COUNTER);
+        od->v_len = sizeof(u32_t);
+        break;
+      case 30: /* snmpEnableAuthenTraps */
+        od->instance = MIB_OBJECT_SCALAR;
+        od->access = MIB_OBJECT_READ_WRITE;
+        od->asn_type = (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG);
+        od->v_len = sizeof(s32_t);
+        break;
+      default:
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("snmp_get_object_def: no such object\n"));
+        od->instance = MIB_OBJECT_NONE;
+        break;
+    };
+  }
+  else
+  {
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("snmp_get_object_def: no scalar\n"));
+    od->instance = MIB_OBJECT_NONE;
+  }
+}
+
+static void
+snmp_get_value(struct obj_def *od, u16_t len, void *value)
+{
+  u32_t *uint_ptr = (u32_t*)value;
+  u8_t id;
+
+  LWIP_UNUSED_ARG(len);
+  LWIP_ASSERT("invalid id", (od->id_inst_ptr[0] >= 0) && (od->id_inst_ptr[0] <= 0xff));
+  id = (u8_t)od->id_inst_ptr[0];
+  switch (id)
+  {
+      case 1: /* snmpInPkts */
+        *uint_ptr = snmpinpkts;
+        break;
+      case 2: /* snmpOutPkts */
+        *uint_ptr = snmpoutpkts;
+        break;
+      case 3: /* snmpInBadVersions */
+        *uint_ptr = snmpinbadversions;
+        break;
+      case 4: /* snmpInBadCommunityNames */
+        *uint_ptr = snmpinbadcommunitynames;
+        break;
+      case 5: /* snmpInBadCommunityUses */
+        *uint_ptr = snmpinbadcommunityuses;
+        break;
+      case 6: /* snmpInASNParseErrs */
+        *uint_ptr = snmpinasnparseerrs;
+        break;
+      case 8: /* snmpInTooBigs */
+        *uint_ptr = snmpintoobigs;
+        break;
+      case 9: /* snmpInNoSuchNames */
+        *uint_ptr = snmpinnosuchnames;
+        break;
+      case 10: /* snmpInBadValues */
+        *uint_ptr = snmpinbadvalues;
+        break;
+      case 11: /* snmpInReadOnlys */
+        *uint_ptr = snmpinreadonlys;
+        break;
+      case 12: /* snmpInGenErrs */
+        *uint_ptr = snmpingenerrs;
+        break;
+      case 13: /* snmpInTotalReqVars */
+        *uint_ptr = snmpintotalreqvars;
+        break;
+      case 14: /* snmpInTotalSetVars */
+        *uint_ptr = snmpintotalsetvars;
+        break;
+      case 15: /* snmpInGetRequests */
+        *uint_ptr = snmpingetrequests;
+        break;
+      case 16: /* snmpInGetNexts */
+        *uint_ptr = snmpingetnexts;
+        break;
+      case 17: /* snmpInSetRequests */
+        *uint_ptr = snmpinsetrequests;
+        break;
+      case 18: /* snmpInGetResponses */
+        *uint_ptr = snmpingetresponses;
+        break;
+      case 19: /* snmpInTraps */
+        *uint_ptr = snmpintraps;
+        break;
+      case 20: /* snmpOutTooBigs */
+        *uint_ptr = snmpouttoobigs;
+        break;
+      case 21: /* snmpOutNoSuchNames */
+        *uint_ptr = snmpoutnosuchnames;
+        break;
+      case 22: /* snmpOutBadValues */
+        *uint_ptr = snmpoutbadvalues;
+        break;
+      case 24: /* snmpOutGenErrs */
+        *uint_ptr = snmpoutgenerrs;
+        break;
+      case 25: /* snmpOutGetRequests */
+        *uint_ptr = snmpoutgetrequests;
+        break;
+      case 26: /* snmpOutGetNexts */
+        *uint_ptr = snmpoutgetnexts;
+        break;
+      case 27: /* snmpOutSetRequests */
+        *uint_ptr = snmpoutsetrequests;
+        break;
+      case 28: /* snmpOutGetResponses */
+        *uint_ptr = snmpoutgetresponses;
+        break;
+      case 29: /* snmpOutTraps */
+        *uint_ptr = snmpouttraps;
+        break;
+      case 30: /* snmpEnableAuthenTraps */
+        *uint_ptr = *snmpenableauthentraps_ptr;
+        break;
+  };
+}
+
+/**
+ * Test snmp object value before setting.
+ *
+ * @param od is the object definition
+ * @param len return value space (in bytes)
+ * @param value points to (varbind) space to copy value from.
+ */
+static u8_t
+snmp_set_test(struct obj_def *od, u16_t len, void *value)
+{
+  u8_t id, set_ok;
+
+  LWIP_UNUSED_ARG(len);
+  set_ok = 0;
+  LWIP_ASSERT("invalid id", (od->id_inst_ptr[0] >= 0) && (od->id_inst_ptr[0] <= 0xff));
+  id = (u8_t)od->id_inst_ptr[0];
+  if (id == 30)
+  {
+    /* snmpEnableAuthenTraps */
+    s32_t *sint_ptr = (s32_t*)value;
+
+    if (snmpenableauthentraps_ptr != &snmpenableauthentraps_default)
+    {
+      /* we should have writable non-volatile mem here */
+      if ((*sint_ptr == 1) || (*sint_ptr == 2))
+      {
+        set_ok = 1;
+      }
+    }
+    else
+    {
+      /* const or hardwired value */
+      if (*sint_ptr == snmpenableauthentraps_default)
+      {
+        set_ok = 1;
+      }
+    }
+  }
+  return set_ok;
+}
+
+static void
+snmp_set_value(struct obj_def *od, u16_t len, void *value)
+{
+  u8_t id;
+
+  LWIP_UNUSED_ARG(len);
+  LWIP_ASSERT("invalid id", (od->id_inst_ptr[0] >= 0) && (od->id_inst_ptr[0] <= 0xff));
+  id = (u8_t)od->id_inst_ptr[0];
+  if (id == 30)
+  {
+    /* snmpEnableAuthenTraps */
+    /* @todo @fixme: which kind of pointer is 'value'? s32_t or u8_t??? */
+    u8_t *ptr = (u8_t*)value;
+    *snmpenableauthentraps_ptr = *ptr;
+  }
+}
+
+#endif /* LWIP_SNMP */
diff --git a/core/lwip/src/core/snmp/mib_structs.c b/core/lwip/src/core/snmp/mib_structs.c
new file mode 100644
index 00000000..2f185cb4
--- /dev/null
+++ b/core/lwip/src/core/snmp/mib_structs.c
@@ -0,0 +1,1174 @@
+/**
+ * @file
+ * MIB tree access/construction functions.
+ */
+
+/*
+ * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * Author: Christiaan Simons <christiaan.simons@axon.tv>
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/snmp_structs.h"
+#include "lwip/memp.h"
+#include "lwip/netif.h"
+
+/** .iso.org.dod.internet address prefix, @see snmp_iso_*() */
+const s32_t prefix[4] = {1, 3, 6, 1};
+
+#define NODE_STACK_SIZE (LWIP_SNMP_OBJ_ID_LEN)
+/** node stack entry (old news?) */
+struct nse
+{
+  /** right child */
+  struct mib_node* r_ptr;
+  /** right child identifier */
+  s32_t r_id;
+  /** right child next level */
+  u8_t r_nl;
+};
+static u8_t node_stack_cnt;
+static struct nse node_stack[NODE_STACK_SIZE];
+
+/**
+ * Pushes nse struct onto stack.
+ */
+static void
+push_node(struct nse* node)
+{
+  LWIP_ASSERT("node_stack_cnt < NODE_STACK_SIZE",node_stack_cnt < NODE_STACK_SIZE);
+  LWIP_DEBUGF(SNMP_MIB_DEBUG,("push_node() node=%p id=%"S32_F"\n",(void*)(node->r_ptr),node->r_id));
+  if (node_stack_cnt < NODE_STACK_SIZE)
+  {
+    node_stack[node_stack_cnt] = *node;
+    node_stack_cnt++;
+  }
+}
+
+/**
+ * Pops nse struct from stack.
+ */
+static void
+pop_node(struct nse* node)
+{
+  if (node_stack_cnt > 0)
+  {
+    node_stack_cnt--;
+    *node = node_stack[node_stack_cnt];
+  }
+  LWIP_DEBUGF(SNMP_MIB_DEBUG,("pop_node() node=%p id=%"S32_F"\n",(void *)(node->r_ptr),node->r_id));
+}
+
+/**
+ * Conversion from ifIndex to lwIP netif
+ * @param ifindex is a s32_t object sub-identifier
+ * @param netif points to returned netif struct pointer
+ */
+void
+snmp_ifindextonetif(s32_t ifindex, struct netif **netif)
+{
+  struct netif *nif = netif_list;
+  s32_t i, ifidx;
+
+  ifidx = ifindex - 1;
+  i = 0;
+  while ((nif != NULL) && (i < ifidx))
+  {
+    nif = nif->next;
+    i++;
+  }
+  *netif = nif;
+}
+
+/**
+ * Conversion from lwIP netif to ifIndex
+ * @param netif points to a netif struct
+ * @param ifidx points to s32_t object sub-identifier
+ */
+void
+snmp_netiftoifindex(struct netif *netif, s32_t *ifidx)
+{
+  struct netif *nif = netif_list;
+  u16_t i;
+
+  i = 0;
+  while ((nif != NULL) && (nif != netif))
+  {
+    nif = nif->next;
+    i++;
+  }
+  *ifidx = i+1;
+}
+
+/**
+ * Conversion from oid to lwIP ip_addr
+ * @param ident points to s32_t ident[4] input
+ * @param ip points to output struct
+ */
+void
+snmp_oidtoip(s32_t *ident, ip_addr_t *ip)
+{
+  IP4_ADDR(ip, ident[0], ident[1], ident[2], ident[3]);
+}
+
+/**
+ * Conversion from lwIP ip_addr to oid
+ * @param ip points to input struct
+ * @param ident points to s32_t ident[4] output
+ */
+void
+snmp_iptooid(ip_addr_t *ip, s32_t *ident)
+{
+  ident[0] = ip4_addr1(ip);
+  ident[1] = ip4_addr2(ip);
+  ident[2] = ip4_addr3(ip);
+  ident[3] = ip4_addr4(ip);
+}
+
+struct mib_list_node *
+snmp_mib_ln_alloc(s32_t id)
+{
+  struct mib_list_node *ln;
+
+  ln = (struct mib_list_node *)memp_malloc(MEMP_SNMP_NODE);
+  if (ln != NULL)
+  {
+    ln->prev = NULL;
+    ln->next = NULL;
+    ln->objid = id;
+    ln->nptr = NULL;
+  }
+  return ln;
+}
+
+void
+snmp_mib_ln_free(struct mib_list_node *ln)
+{
+  memp_free(MEMP_SNMP_NODE, ln);
+}
+
+struct mib_list_rootnode *
+snmp_mib_lrn_alloc(void)
+{
+  struct mib_list_rootnode *lrn;
+
+  lrn = (struct mib_list_rootnode*)memp_malloc(MEMP_SNMP_ROOTNODE);
+  if (lrn != NULL)
+  {
+    lrn->get_object_def = noleafs_get_object_def;
+    lrn->get_value = noleafs_get_value;
+    lrn->set_test = noleafs_set_test;
+    lrn->set_value = noleafs_set_value;
+    lrn->node_type = MIB_NODE_LR;
+    lrn->maxlength = 0;
+    lrn->head = NULL;
+    lrn->tail = NULL;
+    lrn->count = 0;
+  }
+  return lrn;
+}
+
+void
+snmp_mib_lrn_free(struct mib_list_rootnode *lrn)
+{
+  memp_free(MEMP_SNMP_ROOTNODE, lrn);
+}
+
+/**
+ * Inserts node in idx list in a sorted
+ * (ascending order) fashion and
+ * allocates the node if needed.
+ *
+ * @param rn points to the root node
+ * @param objid is the object sub identifier
+ * @param insn points to a pointer to the inserted node
+ *   used for constructing the tree.
+ * @return -1 if failed, 1 if inserted, 2 if present.
+ */
+s8_t
+snmp_mib_node_insert(struct mib_list_rootnode *rn, s32_t objid, struct mib_list_node **insn)
+{
+  struct mib_list_node *nn;
+  s8_t insert;
+
+  LWIP_ASSERT("rn != NULL",rn != NULL);
+
+  /* -1 = malloc failure, 0 = not inserted, 1 = inserted, 2 = was present */
+  insert = 0;
+  if (rn->head == NULL)
+  {
+    /* empty list, add first node */
+    LWIP_DEBUGF(SNMP_MIB_DEBUG,("alloc empty list objid==%"S32_F"\n",objid));
+    nn = snmp_mib_ln_alloc(objid);
+    if (nn != NULL)
+    {
+      rn->head = nn;
+      rn->tail = nn;
+      *insn = nn;
+      insert = 1;
+    }
+    else
+    {
+      insert = -1;
+    }
+  }
+  else
+  {
+    struct mib_list_node *n;
+    /* at least one node is present */
+    n = rn->head;
+    while ((n != NULL) && (insert == 0))
+    {
+      if (n->objid == objid)
+      {
+        /* node is already there */
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("node already there objid==%"S32_F"\n",objid));
+        *insn = n;
+        insert = 2;
+      }
+      else if (n->objid < objid)
+      {
+        if (n->next == NULL)
+        {
+          /* alloc and insert at the tail */
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("alloc ins tail objid==%"S32_F"\n",objid));
+          nn = snmp_mib_ln_alloc(objid);
+          if (nn != NULL)
+          {
+            nn->next = NULL;
+            nn->prev = n;
+            n->next = nn;
+            rn->tail = nn;
+            *insn = nn;
+            insert = 1;
+          }
+          else
+          {
+            /* insertion failure */
+            insert = -1;
+          }
+        }
+        else
+        {
+          /* there's more to explore: traverse list */
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("traverse list\n"));
+          n = n->next;
+        }
+      }
+      else
+      {
+        /* n->objid > objid */
+        /* alloc and insert between n->prev and n */
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("alloc ins n->prev, objid==%"S32_F", n\n",objid));
+        nn = snmp_mib_ln_alloc(objid);
+        if (nn != NULL)
+        {
+          if (n->prev == NULL)
+          {
+            /* insert at the head */
+            nn->next = n;
+            nn->prev = NULL;
+            rn->head = nn;
+            n->prev = nn;
+          }
+          else
+          {
+            /* insert in the middle */
+            nn->next = n;
+            nn->prev = n->prev;
+            n->prev->next = nn;
+            n->prev = nn;
+          }
+          *insn = nn;
+          insert = 1;
+        }
+        else
+        {
+          /* insertion failure */
+          insert = -1;
+        }
+      }
+    }
+  }
+  if (insert == 1)
+  {
+    rn->count += 1;
+  }
+  LWIP_ASSERT("insert != 0",insert != 0);
+  return insert;
+}
+
+/**
+ * Finds node in idx list and returns deletion mark.
+ *
+ * @param rn points to the root node
+ * @param objid  is the object sub identifier
+ * @param fn returns pointer to found node
+ * @return 0 if not found, 1 if deletable,
+ *   2 can't delete (2 or more children), 3 not a list_node
+ */
+s8_t
+snmp_mib_node_find(struct mib_list_rootnode *rn, s32_t objid, struct mib_list_node **fn)
+{
+  s8_t fc;
+  struct mib_list_node *n;
+
+  LWIP_ASSERT("rn != NULL",rn != NULL);
+  n = rn->head;
+  while ((n != NULL) && (n->objid != objid))
+  {
+    n = n->next;
+  }
+  if (n == NULL)
+  {
+    fc = 0;
+  }
+  else if (n->nptr == NULL)
+  {
+    /* leaf, can delete node */
+    fc = 1;
+  }
+  else
+  {
+    struct mib_list_rootnode *r;
+
+    if (n->nptr->node_type == MIB_NODE_LR)
+    {
+      r = (struct mib_list_rootnode *)n->nptr;
+      if (r->count > 1)
+      {
+        /* can't delete node */
+        fc = 2;
+      }
+      else
+      {
+        /* count <= 1, can delete node */
+        fc = 1;
+      }
+    }
+    else
+    {
+      /* other node type */
+      fc = 3;
+    }
+  }
+  *fn = n;
+  return fc;
+}
+
+/**
+ * Removes node from idx list
+ * if it has a single child left.
+ *
+ * @param rn points to the root node
+ * @param n points to the node to delete
+ * @return the nptr to be freed by caller
+ */
+struct mib_list_rootnode *
+snmp_mib_node_delete(struct mib_list_rootnode *rn, struct mib_list_node *n)
+{
+  struct mib_list_rootnode *next;
+
+  LWIP_ASSERT("rn != NULL",rn != NULL);
+  LWIP_ASSERT("n != NULL",n != NULL);
+
+  /* caller must remove this sub-tree */
+  next = (struct mib_list_rootnode*)(n->nptr);
+  rn->count -= 1;
+
+  if (n == rn->head)
+  {
+    rn->head = n->next;
+    if (n->next != NULL)
+    {
+      /* not last node, new list begin */
+      n->next->prev = NULL;
+    }
+  }
+  else if (n == rn->tail)
+  {
+    rn->tail = n->prev;
+    if (n->prev != NULL)
+    {
+      /* not last node, new list end */
+      n->prev->next = NULL;
+    }
+  }
+  else
+  {
+    /* node must be in the middle */
+    n->prev->next = n->next;
+    n->next->prev = n->prev;
+  }
+  LWIP_DEBUGF(SNMP_MIB_DEBUG,("free list objid==%"S32_F"\n",n->objid));
+  snmp_mib_ln_free(n);
+  if (rn->count == 0)
+  {
+    rn->head = NULL;
+    rn->tail = NULL;
+  }
+  return next;
+}
+
+
+
+/**
+ * Searches tree for the supplied (scalar?) object identifier.
+ *
+ * @param node points to the root of the tree ('.internet')
+ * @param ident_len the length of the supplied object identifier
+ * @param ident points to the array of sub identifiers
+ * @param np points to the found object instance (return)
+ * @return pointer to the requested parent (!) node if success, NULL otherwise
+ */
+struct mib_node *
+snmp_search_tree(struct mib_node *node, u8_t ident_len, s32_t *ident, struct snmp_name_ptr *np)
+{
+  u8_t node_type, ext_level;
+
+  ext_level = 0;
+  LWIP_DEBUGF(SNMP_MIB_DEBUG,("node==%p *ident==%"S32_F"\n",(void*)node,*ident));
+  while (node != NULL)
+  {
+    node_type = node->node_type;
+    if ((node_type == MIB_NODE_AR) || (node_type == MIB_NODE_RA))
+    {
+      struct mib_array_node *an;
+      u16_t i;
+
+      if (ident_len > 0)
+      {
+        /* array node (internal ROM or RAM, fixed length) */
+        an = (struct mib_array_node *)node;
+        i = 0;
+        while ((i < an->maxlength) && (an->objid[i] != *ident))
+        {
+          i++;
+        }
+        if (i < an->maxlength)
+        {
+          /* found it, if available proceed to child, otherwise inspect leaf */
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("an->objid[%"U16_F"]==%"S32_F" *ident==%"S32_F"\n",i,an->objid[i],*ident));
+          if (an->nptr[i] == NULL)
+          {
+            /* a scalar leaf OR table,
+               inspect remaining instance number / table index */
+            np->ident_len = ident_len;
+            np->ident = ident;
+            return (struct mib_node*)an;
+          }
+          else
+          {
+            /* follow next child pointer */
+            ident++;
+            ident_len--;
+            node = an->nptr[i];
+          }
+        }
+        else
+        {
+          /* search failed, identifier mismatch (nosuchname) */
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("an search failed *ident==%"S32_F"\n",*ident));
+          return NULL;
+        }
+      }
+      else
+      {
+        /* search failed, short object identifier (nosuchname) */
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("an search failed, short object identifier\n"));
+        return NULL;
+      }
+    }
+    else if(node_type == MIB_NODE_LR)
+    {
+      struct mib_list_rootnode *lrn;
+      struct mib_list_node *ln;
+
+      if (ident_len > 0)
+      {
+        /* list root node (internal 'RAM', variable length) */
+        lrn = (struct mib_list_rootnode *)node;
+        ln = lrn->head;
+        /* iterate over list, head to tail */
+        while ((ln != NULL) && (ln->objid != *ident))
+        {
+          ln = ln->next;
+        }
+        if (ln != NULL)
+        {
+          /* found it, proceed to child */;
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("ln->objid==%"S32_F" *ident==%"S32_F"\n",ln->objid,*ident));
+          if (ln->nptr == NULL)
+          {
+            np->ident_len = ident_len;
+            np->ident = ident;
+            return (struct mib_node*)lrn;
+          }
+          else
+          {
+            /* follow next child pointer */
+            ident_len--;
+            ident++;
+            node = ln->nptr;
+          }
+        }
+        else
+        {
+          /* search failed */
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("ln search failed *ident==%"S32_F"\n",*ident));
+          return NULL;
+        }
+      }
+      else
+      {
+        /* search failed, short object identifier (nosuchname) */
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("ln search failed, short object identifier\n"));
+        return NULL;
+      }
+    }
+    else if(node_type == MIB_NODE_EX)
+    {
+      struct mib_external_node *en;
+      u16_t i, len;
+
+      if (ident_len > 0)
+      {
+        /* external node (addressing and access via functions) */
+        en = (struct mib_external_node *)node;
+
+        i = 0;
+        len = en->level_length(en->addr_inf,ext_level);
+        while ((i < len) && (en->ident_cmp(en->addr_inf,ext_level,i,*ident) != 0))
+        {
+          i++;
+        }
+        if (i < len)
+        {
+          s32_t debug_id;
+
+          en->get_objid(en->addr_inf,ext_level,i,&debug_id);
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("en->objid==%"S32_F" *ident==%"S32_F"\n",debug_id,*ident));
+          if ((ext_level + 1) == en->tree_levels)
+          {
+            np->ident_len = ident_len;
+            np->ident = ident;
+            return (struct mib_node*)en;
+          }
+          else
+          {
+            /* found it, proceed to child */
+            ident_len--;
+            ident++;
+            ext_level++;
+          }
+        }
+        else
+        {
+          /* search failed */
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("en search failed *ident==%"S32_F"\n",*ident));
+          return NULL;
+        }
+      }
+      else
+      {
+        /* search failed, short object identifier (nosuchname) */
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("en search failed, short object identifier\n"));
+        return NULL;
+      }
+    }
+    else if (node_type == MIB_NODE_SC)
+    {
+      mib_scalar_node *sn;
+
+      sn = (mib_scalar_node *)node;
+      if ((ident_len == 1) && (*ident == 0))
+      {
+        np->ident_len = ident_len;
+        np->ident = ident;
+        return (struct mib_node*)sn;
+      }
+      else
+      {
+        /* search failed, short object identifier (nosuchname) */
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("search failed, invalid object identifier length\n"));
+        return NULL;
+      }
+    }
+    else
+    {
+      /* unknown node_type */
+      LWIP_DEBUGF(SNMP_MIB_DEBUG,("search failed node_type %"U16_F" unkown\n",(u16_t)node_type));
+      return NULL;
+    }
+  }
+  /* done, found nothing */
+  LWIP_DEBUGF(SNMP_MIB_DEBUG,("search failed node==%p\n",(void*)node));
+  return NULL;
+}
+
+/**
+ * Test table for presence of at least one table entry.
+ */
+static u8_t
+empty_table(struct mib_node *node)
+{
+  u8_t node_type;
+  u8_t empty = 0;
+
+  if (node != NULL)
+  {
+    node_type = node->node_type;
+    if (node_type == MIB_NODE_LR)
+    {
+      struct mib_list_rootnode *lrn;
+      lrn = (struct mib_list_rootnode *)node;
+      if ((lrn->count == 0) || (lrn->head == NULL))
+      {
+        empty = 1;
+      }
+    }
+    else if ((node_type == MIB_NODE_AR) || (node_type == MIB_NODE_RA))
+    {
+      struct mib_array_node *an;
+      an = (struct mib_array_node *)node;
+      if ((an->maxlength == 0) || (an->nptr == NULL))
+      {
+        empty = 1;
+      }
+    }
+    else if (node_type == MIB_NODE_EX)
+    {
+      struct mib_external_node *en;
+      en = (struct mib_external_node *)node;
+      if (en->tree_levels == 0)
+      {
+        empty = 1;
+      }
+    }
+  }
+  return empty;
+}
+
+/**
+ * Tree expansion.
+ */
+struct mib_node *
+snmp_expand_tree(struct mib_node *node, u8_t ident_len, s32_t *ident, struct snmp_obj_id *oidret)
+{
+  u8_t node_type, ext_level, climb_tree;
+
+  ext_level = 0;
+  /* reset node stack */
+  node_stack_cnt = 0;
+  while (node != NULL)
+  {
+    climb_tree = 0;
+    node_type = node->node_type;
+    if ((node_type == MIB_NODE_AR) || (node_type == MIB_NODE_RA))
+    {
+      struct mib_array_node *an;
+      u16_t i;
+
+      /* array node (internal ROM or RAM, fixed length) */
+      an = (struct mib_array_node *)node;
+      if (ident_len > 0)
+      {
+        i = 0;
+        while ((i < an->maxlength) && (an->objid[i] < *ident))
+        {
+          i++;
+        }
+        if (i < an->maxlength)
+        {
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("an->objid[%"U16_F"]==%"S32_F" *ident==%"S32_F"\n",i,an->objid[i],*ident));
+          /* add identifier to oidret */
+          oidret->id[oidret->len] = an->objid[i];
+          (oidret->len)++;
+
+          if (an->nptr[i] == NULL)
+          {
+            LWIP_DEBUGF(SNMP_MIB_DEBUG,("leaf node\n"));
+            /* leaf node (e.g. in a fixed size table) */
+            if (an->objid[i] > *ident)
+            {
+              return (struct mib_node*)an;
+            }
+            else if ((i + 1) < an->maxlength)
+            {
+              /* an->objid[i] == *ident */
+              (oidret->len)--;
+              oidret->id[oidret->len] = an->objid[i + 1];
+              (oidret->len)++;
+              return (struct mib_node*)an;
+            }
+            else
+            {
+              /* (i + 1) == an->maxlength */
+              (oidret->len)--;
+              climb_tree = 1;
+            }
+          }
+          else
+          {
+            u8_t j;
+            struct nse cur_node;
+
+            LWIP_DEBUGF(SNMP_MIB_DEBUG,("non-leaf node\n"));
+            /* non-leaf, store right child ptr and id */
+            LWIP_ASSERT("i < 0xff", i < 0xff);
+            j = (u8_t)i + 1;
+            while ((j < an->maxlength) && (empty_table(an->nptr[j])))
+            {
+              j++;
+            }
+            if (j < an->maxlength)
+            {
+              cur_node.r_ptr = an->nptr[j];
+              cur_node.r_id = an->objid[j];
+              cur_node.r_nl = 0;
+            }
+            else
+            {
+              cur_node.r_ptr = NULL;
+            }
+            push_node(&cur_node);
+            if (an->objid[i] == *ident)
+            {
+              ident_len--;
+              ident++;
+            }
+            else
+            {
+              /* an->objid[i] < *ident */
+              ident_len = 0;
+            }
+            /* follow next child pointer */
+            node = an->nptr[i];
+          }
+        }
+        else
+        {
+          /* i == an->maxlength */
+          climb_tree = 1;
+        }
+      }
+      else
+      {
+        u8_t j;
+        /* ident_len == 0, complete with leftmost '.thing' */
+        j = 0;
+        while ((j < an->maxlength) && empty_table(an->nptr[j]))
+        {
+          j++;
+        }
+        if (j < an->maxlength)
+        {
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("left an->objid[j]==%"S32_F"\n",an->objid[j]));
+          oidret->id[oidret->len] = an->objid[j];
+          (oidret->len)++;
+          if (an->nptr[j] == NULL)
+          {
+            /* leaf node */
+            return (struct mib_node*)an;
+          }
+          else
+          {
+            /* no leaf, continue */
+            node = an->nptr[j];
+          }
+        }
+        else
+        {
+          /* j == an->maxlength */
+          climb_tree = 1;
+        }
+      }
+    }
+    else if(node_type == MIB_NODE_LR)
+    {
+      struct mib_list_rootnode *lrn;
+      struct mib_list_node *ln;
+
+      /* list root node (internal 'RAM', variable length) */
+      lrn = (struct mib_list_rootnode *)node;
+      if (ident_len > 0)
+      {
+        ln = lrn->head;
+        /* iterate over list, head to tail */
+        while ((ln != NULL) && (ln->objid < *ident))
+        {
+          ln = ln->next;
+        }
+        if (ln != NULL)
+        {
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("ln->objid==%"S32_F" *ident==%"S32_F"\n",ln->objid,*ident));
+          oidret->id[oidret->len] = ln->objid;
+          (oidret->len)++;
+          if (ln->nptr == NULL)
+          {
+            /* leaf node */
+            if (ln->objid > *ident)
+            {
+              return (struct mib_node*)lrn;
+            }
+            else if (ln->next != NULL)
+            {
+              /* ln->objid == *ident */
+              (oidret->len)--;
+              oidret->id[oidret->len] = ln->next->objid;
+              (oidret->len)++;
+              return (struct mib_node*)lrn;
+            }
+            else
+            {
+              /* ln->next == NULL */
+              (oidret->len)--;
+              climb_tree = 1;
+            }
+          }
+          else
+          {
+            struct mib_list_node *jn;
+            struct nse cur_node;
+
+            /* non-leaf, store right child ptr and id */
+            jn = ln->next;
+            while ((jn != NULL) && empty_table(jn->nptr))
+            {
+              jn = jn->next;
+            }
+            if (jn != NULL)
+            {
+              cur_node.r_ptr = jn->nptr;
+              cur_node.r_id = jn->objid;
+              cur_node.r_nl = 0;
+            }
+            else
+            {
+              cur_node.r_ptr = NULL;
+            }
+            push_node(&cur_node);
+            if (ln->objid == *ident)
+            {
+              ident_len--;
+              ident++;
+            }
+            else
+            {
+              /* ln->objid < *ident */
+              ident_len = 0;
+            }
+            /* follow next child pointer */
+            node = ln->nptr;
+          }
+
+        }
+        else
+        {
+          /* ln == NULL */
+          climb_tree = 1;
+        }
+      }
+      else
+      {
+        struct mib_list_node *jn;
+        /* ident_len == 0, complete with leftmost '.thing' */
+        jn = lrn->head;
+        while ((jn != NULL) && empty_table(jn->nptr))
+        {
+          jn = jn->next;
+        }
+        if (jn != NULL)
+        {
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("left jn->objid==%"S32_F"\n",jn->objid));
+          oidret->id[oidret->len] = jn->objid;
+          (oidret->len)++;
+          if (jn->nptr == NULL)
+          {
+            /* leaf node */
+            LWIP_DEBUGF(SNMP_MIB_DEBUG,("jn->nptr == NULL\n"));
+            return (struct mib_node*)lrn;
+          }
+          else
+          {
+            /* no leaf, continue */
+            node = jn->nptr;
+          }
+        }
+        else
+        {
+          /* jn == NULL */
+          climb_tree = 1;
+        }
+      }
+    }
+    else if(node_type == MIB_NODE_EX)
+    {
+      struct mib_external_node *en;
+      s32_t ex_id;
+
+      /* external node (addressing and access via functions) */
+      en = (struct mib_external_node *)node;
+      if (ident_len > 0)
+      {
+        u16_t i, len;
+
+        i = 0;
+        len = en->level_length(en->addr_inf,ext_level);
+        while ((i < len) && (en->ident_cmp(en->addr_inf,ext_level,i,*ident) < 0))
+        {
+          i++;
+        }
+        if (i < len)
+        {
+          /* add identifier to oidret */
+          en->get_objid(en->addr_inf,ext_level,i,&ex_id);
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("en->objid[%"U16_F"]==%"S32_F" *ident==%"S32_F"\n",i,ex_id,*ident));
+          oidret->id[oidret->len] = ex_id;
+          (oidret->len)++;
+
+          if ((ext_level + 1) == en->tree_levels)
+          {
+            LWIP_DEBUGF(SNMP_MIB_DEBUG,("leaf node\n"));
+            /* leaf node */
+            if (ex_id > *ident)
+            {
+              return (struct mib_node*)en;
+            }
+            else if ((i + 1) < len)
+            {
+              /* ex_id == *ident */
+              en->get_objid(en->addr_inf,ext_level,i + 1,&ex_id);
+              (oidret->len)--;
+              oidret->id[oidret->len] = ex_id;
+              (oidret->len)++;
+              return (struct mib_node*)en;
+            }
+            else
+            {
+              /* (i + 1) == len */
+              (oidret->len)--;
+              climb_tree = 1;
+            }
+          }
+          else
+          {
+            u8_t j;
+            struct nse cur_node;
+
+            LWIP_DEBUGF(SNMP_MIB_DEBUG,("non-leaf node\n"));
+            /* non-leaf, store right child ptr and id */
+            LWIP_ASSERT("i < 0xff", i < 0xff);
+            j = (u8_t)i + 1;
+            if (j < len)
+            {
+              /* right node is the current external node */
+              cur_node.r_ptr = node;
+              en->get_objid(en->addr_inf,ext_level,j,&cur_node.r_id);
+              cur_node.r_nl = ext_level + 1;
+            }
+            else
+            {
+              cur_node.r_ptr = NULL;
+            }
+            push_node(&cur_node);
+            if (en->ident_cmp(en->addr_inf,ext_level,i,*ident) == 0)
+            {
+              ident_len--;
+              ident++;
+            }
+            else
+            {
+              /* external id < *ident */
+              ident_len = 0;
+            }
+            /* proceed to child */
+            ext_level++;
+          }
+        }
+        else
+        {
+          /* i == len (en->level_len()) */
+          climb_tree = 1;
+        }
+      }
+      else
+      {
+        /* ident_len == 0, complete with leftmost '.thing' */
+        en->get_objid(en->addr_inf,ext_level,0,&ex_id);
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("left en->objid==%"S32_F"\n",ex_id));
+        oidret->id[oidret->len] = ex_id;
+        (oidret->len)++;
+        if ((ext_level + 1) == en->tree_levels)
+        {
+          /* leaf node */
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("(ext_level + 1) == en->tree_levels\n"));
+          return (struct mib_node*)en;
+        }
+        else
+        {
+          /* no leaf, proceed to child */
+          ext_level++;
+        }
+      }
+    }
+    else if(node_type == MIB_NODE_SC)
+    {
+      mib_scalar_node *sn;
+
+      /* scalar node  */
+      sn = (mib_scalar_node *)node;
+      if (ident_len > 0)
+      {
+        /* at .0 */
+        climb_tree = 1;
+      }
+      else
+      {
+        /* ident_len == 0, complete object identifier */
+        oidret->id[oidret->len] = 0;
+        (oidret->len)++;
+        /* leaf node */
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("completed scalar leaf\n"));
+        return (struct mib_node*)sn;
+      }
+    }
+    else
+    {
+      /* unknown/unhandled node_type */
+      LWIP_DEBUGF(SNMP_MIB_DEBUG,("expand failed node_type %"U16_F" unkown\n",(u16_t)node_type));
+      return NULL;
+    }
+
+    if (climb_tree)
+    {
+      struct nse child;
+
+      /* find right child ptr */
+      child.r_ptr = NULL;
+      child.r_id = 0;
+      child.r_nl = 0;
+      while ((node_stack_cnt > 0) && (child.r_ptr == NULL))
+      {
+        pop_node(&child);
+        /* trim returned oid */
+        (oidret->len)--;
+      }
+      if (child.r_ptr != NULL)
+      {
+        /* incoming ident is useless beyond this point */
+        ident_len = 0;
+        oidret->id[oidret->len] = child.r_id;
+        oidret->len++;
+        node = child.r_ptr;
+        ext_level = child.r_nl;
+      }
+      else
+      {
+        /* tree ends here ... */
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("expand failed, tree ends here\n"));
+        return NULL;
+      }
+    }
+  }
+  /* done, found nothing */
+  LWIP_DEBUGF(SNMP_MIB_DEBUG,("expand failed node==%p\n",(void*)node));
+  return NULL;
+}
+
+/**
+ * Test object identifier for the iso.org.dod.internet prefix.
+ *
+ * @param ident_len the length of the supplied object identifier
+ * @param ident points to the array of sub identifiers
+ * @return 1 if it matches, 0 otherwise
+ */
+u8_t
+snmp_iso_prefix_tst(u8_t ident_len, s32_t *ident)
+{
+  if ((ident_len > 3) &&
+      (ident[0] == 1) && (ident[1] == 3) &&
+      (ident[2] == 6) && (ident[3] == 1))
+  {
+    return 1;
+  }
+  else
+  {
+    return 0;
+  }
+}
+
+/**
+ * Expands object identifier to the iso.org.dod.internet
+ * prefix for use in getnext operation.
+ *
+ * @param ident_len the length of the supplied object identifier
+ * @param ident points to the array of sub identifiers
+ * @param oidret points to returned expanded object identifier
+ * @return 1 if it matches, 0 otherwise
+ *
+ * @note ident_len 0 is allowed, expanding to the first known object id!!
+ */
+u8_t
+snmp_iso_prefix_expand(u8_t ident_len, s32_t *ident, struct snmp_obj_id *oidret)
+{
+  const s32_t *prefix_ptr;
+  s32_t *ret_ptr;
+  u8_t i;
+
+  i = 0;
+  prefix_ptr = &prefix[0];
+  ret_ptr = &oidret->id[0];
+  ident_len = ((ident_len < 4)?ident_len:4);
+  while ((i < ident_len) && ((*ident) <= (*prefix_ptr)))
+  {
+    *ret_ptr++ = *prefix_ptr++;
+    ident++;
+    i++;
+  }
+  if (i == ident_len)
+  {
+    /* match, complete missing bits */
+    while (i < 4)
+    {
+      *ret_ptr++ = *prefix_ptr++;
+      i++;
+    }
+    oidret->len = i;
+    return 1;
+  }
+  else
+  {
+    /* i != ident_len */
+    return 0;
+  }
+}
+
+#endif /* LWIP_SNMP */
diff --git a/core/lwip/src/core/snmp/msg_in.c b/core/lwip/src/core/snmp/msg_in.c
new file mode 100644
index 00000000..2dfb55b2
--- /dev/null
+++ b/core/lwip/src/core/snmp/msg_in.c
@@ -0,0 +1,1437 @@
+/**
+ * @file
+ * SNMP input message processing (RFC1157).
+ */
+
+/*
+ * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * Author: Christiaan Simons <christiaan.simons@axon.tv>
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/snmp.h"
+#include "lwip/snmp_asn1.h"
+#include "lwip/snmp_msg.h"
+#include "lwip/snmp_structs.h"
+#include "lwip/ip_addr.h"
+#include "lwip/memp.h"
+#include "lwip/udp.h"
+#include "lwip/stats.h"
+
+#include <string.h>
+
+/* public (non-static) constants */
+/** SNMP v1 == 0 */
+const s32_t snmp_version = 0;
+/** default SNMP community string */
+const char snmp_publiccommunity[7] = "public";
+
+/* statically allocated buffers for SNMP_CONCURRENT_REQUESTS */
+struct snmp_msg_pstat msg_input_list[SNMP_CONCURRENT_REQUESTS];
+/* UDP Protocol Control Block */
+struct udp_pcb *snmp1_pcb;
+
+static void snmp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port);
+static err_t snmp_pdu_header_check(struct pbuf *p, u16_t ofs, u16_t pdu_len, u16_t *ofs_ret, struct snmp_msg_pstat *m_stat);
+static err_t snmp_pdu_dec_varbindlist(struct pbuf *p, u16_t ofs, u16_t *ofs_ret, struct snmp_msg_pstat *m_stat);
+
+
+/**
+ * Starts SNMP Agent.
+ * Allocates UDP pcb and binds it to IP_ADDR_ANY port 161.
+ */
+void
+snmp_init(void)
+{
+  struct snmp_msg_pstat *msg_ps;
+  u8_t i;
+
+  snmp1_pcb = udp_new();
+  if (snmp1_pcb != NULL)
+  {
+    udp_recv(snmp1_pcb, snmp_recv, (void *)SNMP_IN_PORT);
+    udp_bind(snmp1_pcb, IP_ADDR_ANY, SNMP_IN_PORT);
+  }
+  msg_ps = &msg_input_list[0];
+  for (i=0; i<SNMP_CONCURRENT_REQUESTS; i++)
+  {
+    msg_ps->state = SNMP_MSG_EMPTY;
+    msg_ps->error_index = 0;
+    msg_ps->error_status = SNMP_ES_NOERROR;
+    msg_ps++;
+  }
+  trap_msg.pcb = snmp1_pcb;
+
+#ifdef SNMP_PRIVATE_MIB_INIT
+  /* If defined, rhis must be a function-like define to initialize the
+   * private MIB after the stack has been initialized.
+   * The private MIB can also be initialized in tcpip_callback (or after
+   * the stack is initialized), this define is only for convenience. */
+  SNMP_PRIVATE_MIB_INIT();
+#endif /* SNMP_PRIVATE_MIB_INIT */
+
+  /* The coldstart trap will only be output
+     if our outgoing interface is up & configured  */
+  snmp_coldstart_trap();
+}
+
+static void
+snmp_error_response(struct snmp_msg_pstat *msg_ps, u8_t error)
+{
+  snmp_varbind_list_free(&msg_ps->outvb);
+  msg_ps->outvb = msg_ps->invb;
+  msg_ps->invb.head = NULL;
+  msg_ps->invb.tail = NULL;
+  msg_ps->invb.count = 0;
+  msg_ps->error_status = error;
+  msg_ps->error_index = 1 + msg_ps->vb_idx;
+  snmp_send_response(msg_ps);
+  snmp_varbind_list_free(&msg_ps->outvb);
+  msg_ps->state = SNMP_MSG_EMPTY;
+}
+
+static void
+snmp_ok_response(struct snmp_msg_pstat *msg_ps)
+{
+  err_t err_ret;
+
+  err_ret = snmp_send_response(msg_ps);
+  if (err_ret == ERR_MEM)
+  {
+    /* serious memory problem, can't return tooBig */
+  }
+  else
+  {
+    LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_msg_event = %"S32_F"\n",msg_ps->error_status));
+  }
+  /* free varbinds (if available) */
+  snmp_varbind_list_free(&msg_ps->invb);
+  snmp_varbind_list_free(&msg_ps->outvb);
+  msg_ps->state = SNMP_MSG_EMPTY;
+}
+
+/**
+ * Service an internal or external event for SNMP GET.
+ *
+ * @param request_id identifies requests from 0 to (SNMP_CONCURRENT_REQUESTS-1)
+ * @param msg_ps points to the assosicated message process state
+ */
+static void
+snmp_msg_get_event(u8_t request_id, struct snmp_msg_pstat *msg_ps)
+{
+  LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_msg_get_event: msg_ps->state==%"U16_F"\n",(u16_t)msg_ps->state));
+
+  if (msg_ps->state == SNMP_MSG_EXTERNAL_GET_OBJDEF)
+  {
+    struct mib_external_node *en;
+    struct snmp_name_ptr np;
+
+    /* get_object_def() answer*/
+    en = msg_ps->ext_mib_node;
+    np = msg_ps->ext_name_ptr;
+
+    /* translate answer into a known lifeform */
+    en->get_object_def_a(request_id, np.ident_len, np.ident, &msg_ps->ext_object_def);
+    if ((msg_ps->ext_object_def.instance != MIB_OBJECT_NONE) &&
+        (msg_ps->ext_object_def.access & MIB_ACCESS_READ))
+    {
+      msg_ps->state = SNMP_MSG_EXTERNAL_GET_VALUE;
+      en->get_value_q(request_id, &msg_ps->ext_object_def);
+    }
+    else
+    {
+      en->get_object_def_pc(request_id, np.ident_len, np.ident);
+      /* search failed, object id points to unknown object (nosuchname) */
+      snmp_error_response(msg_ps,SNMP_ES_NOSUCHNAME);
+    }
+  }
+  else if (msg_ps->state == SNMP_MSG_EXTERNAL_GET_VALUE)
+  {
+    struct mib_external_node *en;
+    struct snmp_varbind *vb;
+
+    /* get_value() answer */
+    en = msg_ps->ext_mib_node;
+
+    /* allocate output varbind */
+    vb = (struct snmp_varbind *)memp_malloc(MEMP_SNMP_VARBIND);
+    LWIP_ASSERT("vb != NULL",vb != NULL);
+    if (vb != NULL)
+    {
+      vb->next = NULL;
+      vb->prev = NULL;
+
+      /* move name from invb to outvb */
+      vb->ident = msg_ps->vb_ptr->ident;
+      vb->ident_len = msg_ps->vb_ptr->ident_len;
+      /* ensure this memory is refereced once only */
+      msg_ps->vb_ptr->ident = NULL;
+      msg_ps->vb_ptr->ident_len = 0;
+
+      vb->value_type = msg_ps->ext_object_def.asn_type;
+      LWIP_ASSERT("invalid length", msg_ps->ext_object_def.v_len <= 0xff);
+      vb->value_len = (u8_t)msg_ps->ext_object_def.v_len;
+      if (vb->value_len > 0)
+      {
+        LWIP_ASSERT("SNMP_MAX_OCTET_STRING_LEN is configured too low", vb->value_len <= SNMP_MAX_VALUE_SIZE);
+        vb->value = memp_malloc(MEMP_SNMP_VALUE);
+        LWIP_ASSERT("vb->value != NULL",vb->value != NULL);
+        if (vb->value != NULL)
+        {
+          en->get_value_a(request_id, &msg_ps->ext_object_def, vb->value_len, vb->value);
+          snmp_varbind_tail_add(&msg_ps->outvb, vb);
+          /* search again (if vb_idx < msg_ps->invb.count) */
+          msg_ps->state = SNMP_MSG_SEARCH_OBJ;
+          msg_ps->vb_idx += 1;
+        }
+        else
+        {
+          en->get_value_pc(request_id, &msg_ps->ext_object_def);
+          LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_msg_event: no variable space\n"));
+          msg_ps->vb_ptr->ident = vb->ident;
+          msg_ps->vb_ptr->ident_len = vb->ident_len;
+          memp_free(MEMP_SNMP_VARBIND, vb);
+          snmp_error_response(msg_ps,SNMP_ES_TOOBIG);
+        }
+      }
+      else
+      {
+        /* vb->value_len == 0, empty value (e.g. empty string) */
+        en->get_value_a(request_id, &msg_ps->ext_object_def, 0, NULL);
+        vb->value = NULL;
+        snmp_varbind_tail_add(&msg_ps->outvb, vb);
+        /* search again (if vb_idx < msg_ps->invb.count) */
+        msg_ps->state = SNMP_MSG_SEARCH_OBJ;
+        msg_ps->vb_idx += 1;
+      }
+    }
+    else
+    {
+      en->get_value_pc(request_id, &msg_ps->ext_object_def);
+      LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_msg_event: no outvb space\n"));
+      snmp_error_response(msg_ps,SNMP_ES_TOOBIG);
+    }
+  }
+
+  while ((msg_ps->state == SNMP_MSG_SEARCH_OBJ) &&
+         (msg_ps->vb_idx < msg_ps->invb.count))
+  {
+    struct mib_node *mn;
+    struct snmp_name_ptr np;
+
+    if (msg_ps->vb_idx == 0)
+    {
+      msg_ps->vb_ptr = msg_ps->invb.head;
+    }
+    else
+    {
+      msg_ps->vb_ptr = msg_ps->vb_ptr->next;
+    }
+    /** test object identifier for .iso.org.dod.internet prefix */
+    if (snmp_iso_prefix_tst(msg_ps->vb_ptr->ident_len,  msg_ps->vb_ptr->ident))
+    {
+      mn = snmp_search_tree((struct mib_node*)&internet, msg_ps->vb_ptr->ident_len - 4,
+                             msg_ps->vb_ptr->ident + 4, &np);
+      if (mn != NULL)
+      {
+        if (mn->node_type == MIB_NODE_EX)
+        {
+          /* external object */
+          struct mib_external_node *en = (struct mib_external_node*)mn;
+
+          msg_ps->state = SNMP_MSG_EXTERNAL_GET_OBJDEF;
+          /* save en && args in msg_ps!! */
+          msg_ps->ext_mib_node = en;
+          msg_ps->ext_name_ptr = np;
+
+          en->get_object_def_q(en->addr_inf, request_id, np.ident_len, np.ident);
+        }
+        else
+        {
+          /* internal object */
+          struct obj_def object_def;
+
+          msg_ps->state = SNMP_MSG_INTERNAL_GET_OBJDEF;
+          mn->get_object_def(np.ident_len, np.ident, &object_def);
+          if ((object_def.instance != MIB_OBJECT_NONE) &&
+            (object_def.access & MIB_ACCESS_READ))
+          {
+            mn = mn;
+          }
+          else
+          {
+            /* search failed, object id points to unknown object (nosuchname) */
+            mn =  NULL;
+          }
+          if (mn != NULL)
+          {
+            struct snmp_varbind *vb;
+
+            msg_ps->state = SNMP_MSG_INTERNAL_GET_VALUE;
+            /* allocate output varbind */
+            vb = (struct snmp_varbind *)memp_malloc(MEMP_SNMP_VARBIND);
+            LWIP_ASSERT("vb != NULL",vb != NULL);
+            if (vb != NULL)
+            {
+              vb->next = NULL;
+              vb->prev = NULL;
+
+              /* move name from invb to outvb */
+              vb->ident = msg_ps->vb_ptr->ident;
+              vb->ident_len = msg_ps->vb_ptr->ident_len;
+              /* ensure this memory is refereced once only */
+              msg_ps->vb_ptr->ident = NULL;
+              msg_ps->vb_ptr->ident_len = 0;
+
+              vb->value_type = object_def.asn_type;
+              LWIP_ASSERT("invalid length", object_def.v_len <= 0xff);
+              vb->value_len = (u8_t)object_def.v_len;
+              if (vb->value_len > 0)
+              {
+                LWIP_ASSERT("SNMP_MAX_OCTET_STRING_LEN is configured too low",
+                  vb->value_len <= SNMP_MAX_VALUE_SIZE);
+                vb->value = memp_malloc(MEMP_SNMP_VALUE);
+                LWIP_ASSERT("vb->value != NULL",vb->value != NULL);
+                if (vb->value != NULL)
+                {
+                  mn->get_value(&object_def, vb->value_len, vb->value);
+                  snmp_varbind_tail_add(&msg_ps->outvb, vb);
+                  msg_ps->state = SNMP_MSG_SEARCH_OBJ;
+                  msg_ps->vb_idx += 1;
+                }
+                else
+                {
+                  LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_msg_event: couldn't allocate variable space\n"));
+                  msg_ps->vb_ptr->ident = vb->ident;
+                  msg_ps->vb_ptr->ident_len = vb->ident_len;
+                  memp_free(MEMP_SNMP_VARBIND, vb);
+                  snmp_error_response(msg_ps,SNMP_ES_TOOBIG);
+                }
+              }
+              else
+              {
+                /* vb->value_len == 0, empty value (e.g. empty string) */
+                vb->value = NULL;
+                snmp_varbind_tail_add(&msg_ps->outvb, vb);
+                msg_ps->state = SNMP_MSG_SEARCH_OBJ;
+                msg_ps->vb_idx += 1;
+              }
+            }
+            else
+            {
+              LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_msg_event: couldn't allocate outvb space\n"));
+              snmp_error_response(msg_ps,SNMP_ES_TOOBIG);
+            }
+          }
+        }
+      }
+    }
+    else
+    {
+      mn = NULL;
+    }
+    if (mn == NULL)
+    {
+      /* mn == NULL, noSuchName */
+      snmp_error_response(msg_ps,SNMP_ES_NOSUCHNAME);
+    }
+  }
+  if ((msg_ps->state == SNMP_MSG_SEARCH_OBJ) &&
+      (msg_ps->vb_idx == msg_ps->invb.count))
+  {
+    snmp_ok_response(msg_ps);
+  }
+}
+
+/**
+ * Service an internal or external event for SNMP GETNEXT.
+ *
+ * @param request_id identifies requests from 0 to (SNMP_CONCURRENT_REQUESTS-1)
+ * @param msg_ps points to the assosicated message process state
+ */
+static void
+snmp_msg_getnext_event(u8_t request_id, struct snmp_msg_pstat *msg_ps)
+{
+  LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_msg_getnext_event: msg_ps->state==%"U16_F"\n",(u16_t)msg_ps->state));
+
+  if (msg_ps->state == SNMP_MSG_EXTERNAL_GET_OBJDEF)
+  {
+    struct mib_external_node *en;
+
+    /* get_object_def() answer*/
+    en = msg_ps->ext_mib_node;
+
+    /* translate answer into a known lifeform */
+    en->get_object_def_a(request_id, 1, &msg_ps->ext_oid.id[msg_ps->ext_oid.len - 1], &msg_ps->ext_object_def);
+    if (msg_ps->ext_object_def.instance != MIB_OBJECT_NONE)
+    {
+      msg_ps->state = SNMP_MSG_EXTERNAL_GET_VALUE;
+      en->get_value_q(request_id, &msg_ps->ext_object_def);
+    }
+    else
+    {
+      en->get_object_def_pc(request_id, 1, &msg_ps->ext_oid.id[msg_ps->ext_oid.len - 1]);
+      /* search failed, object id points to unknown object (nosuchname) */
+      snmp_error_response(msg_ps,SNMP_ES_NOSUCHNAME);
+    }
+  }
+  else if (msg_ps->state == SNMP_MSG_EXTERNAL_GET_VALUE)
+  {
+    struct mib_external_node *en;
+    struct snmp_varbind *vb;
+
+    /* get_value() answer */
+    en = msg_ps->ext_mib_node;
+
+    LWIP_ASSERT("invalid length", msg_ps->ext_object_def.v_len <= 0xff);
+    vb = snmp_varbind_alloc(&msg_ps->ext_oid,
+                            msg_ps->ext_object_def.asn_type,
+                            (u8_t)msg_ps->ext_object_def.v_len);
+    if (vb != NULL)
+    {
+      en->get_value_a(request_id, &msg_ps->ext_object_def, vb->value_len, vb->value);
+      snmp_varbind_tail_add(&msg_ps->outvb, vb);
+      msg_ps->state = SNMP_MSG_SEARCH_OBJ;
+      msg_ps->vb_idx += 1;
+    }
+    else
+    {
+      en->get_value_pc(request_id, &msg_ps->ext_object_def);
+      LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_msg_getnext_event: couldn't allocate outvb space\n"));
+      snmp_error_response(msg_ps,SNMP_ES_TOOBIG);
+    }
+  }
+
+  while ((msg_ps->state == SNMP_MSG_SEARCH_OBJ) &&
+         (msg_ps->vb_idx < msg_ps->invb.count))
+  {
+    struct mib_node *mn;
+    struct snmp_obj_id oid;
+
+    if (msg_ps->vb_idx == 0)
+    {
+      msg_ps->vb_ptr = msg_ps->invb.head;
+    }
+    else
+    {
+      msg_ps->vb_ptr = msg_ps->vb_ptr->next;
+    }
+    if (snmp_iso_prefix_expand(msg_ps->vb_ptr->ident_len, msg_ps->vb_ptr->ident, &oid))
+    {
+      if (msg_ps->vb_ptr->ident_len > 3)
+      {
+        /* can offset ident_len and ident */
+        mn = snmp_expand_tree((struct mib_node*)&internet,
+                              msg_ps->vb_ptr->ident_len - 4,
+                              msg_ps->vb_ptr->ident + 4, &oid);
+      }
+      else
+      {
+        /* can't offset ident_len -4, ident + 4 */
+        mn = snmp_expand_tree((struct mib_node*)&internet, 0, NULL, &oid);
+      }
+    }
+    else
+    {
+      mn = NULL;
+    }
+    if (mn != NULL)
+    {
+      if (mn->node_type == MIB_NODE_EX)
+      {
+        /* external object */
+        struct mib_external_node *en = (struct mib_external_node*)mn;
+
+        msg_ps->state = SNMP_MSG_EXTERNAL_GET_OBJDEF;
+        /* save en && args in msg_ps!! */
+        msg_ps->ext_mib_node = en;
+        msg_ps->ext_oid = oid;
+
+        en->get_object_def_q(en->addr_inf, request_id, 1, &oid.id[oid.len - 1]);
+      }
+      else
+      {
+        /* internal object */
+        struct obj_def object_def;
+        struct snmp_varbind *vb;
+
+        msg_ps->state = SNMP_MSG_INTERNAL_GET_OBJDEF;
+        mn->get_object_def(1, &oid.id[oid.len - 1], &object_def);
+
+        LWIP_ASSERT("invalid length", object_def.v_len <= 0xff);
+        vb = snmp_varbind_alloc(&oid, object_def.asn_type, (u8_t)object_def.v_len);
+        if (vb != NULL)
+        {
+          msg_ps->state = SNMP_MSG_INTERNAL_GET_VALUE;
+          mn->get_value(&object_def, object_def.v_len, vb->value);
+          snmp_varbind_tail_add(&msg_ps->outvb, vb);
+          msg_ps->state = SNMP_MSG_SEARCH_OBJ;
+          msg_ps->vb_idx += 1;
+        }
+        else
+        {
+          LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_recv couldn't allocate outvb space\n"));
+          snmp_error_response(msg_ps,SNMP_ES_TOOBIG);
+        }
+      }
+    }
+    if (mn == NULL)
+    {
+      /* mn == NULL, noSuchName */
+      snmp_error_response(msg_ps,SNMP_ES_NOSUCHNAME);
+    }
+  }
+  if ((msg_ps->state == SNMP_MSG_SEARCH_OBJ) &&
+      (msg_ps->vb_idx == msg_ps->invb.count))
+  {
+    snmp_ok_response(msg_ps);
+  }
+}
+
+/**
+ * Service an internal or external event for SNMP SET.
+ *
+ * @param request_id identifies requests from 0 to (SNMP_CONCURRENT_REQUESTS-1)
+ * @param msg_ps points to the assosicated message process state
+ */
+static void
+snmp_msg_set_event(u8_t request_id, struct snmp_msg_pstat *msg_ps)
+{
+  LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_msg_set_event: msg_ps->state==%"U16_F"\n",(u16_t)msg_ps->state));
+
+  if (msg_ps->state == SNMP_MSG_EXTERNAL_GET_OBJDEF)
+  {
+    struct mib_external_node *en;
+    struct snmp_name_ptr np;
+
+    /* get_object_def() answer*/
+    en = msg_ps->ext_mib_node;
+    np = msg_ps->ext_name_ptr;
+
+    /* translate answer into a known lifeform */
+    en->get_object_def_a(request_id, np.ident_len, np.ident, &msg_ps->ext_object_def);
+    if (msg_ps->ext_object_def.instance != MIB_OBJECT_NONE)
+    {
+      msg_ps->state = SNMP_MSG_EXTERNAL_SET_TEST;
+      en->set_test_q(request_id, &msg_ps->ext_object_def);
+    }
+    else
+    {
+      en->get_object_def_pc(request_id, np.ident_len, np.ident);
+      /* search failed, object id points to unknown object (nosuchname) */
+      snmp_error_response(msg_ps,SNMP_ES_NOSUCHNAME);
+    }
+  }
+  else if (msg_ps->state == SNMP_MSG_EXTERNAL_SET_TEST)
+  {
+    struct mib_external_node *en;
+
+    /* set_test() answer*/
+    en = msg_ps->ext_mib_node;
+
+    if (msg_ps->ext_object_def.access & MIB_ACCESS_WRITE)
+    {
+       if ((msg_ps->ext_object_def.asn_type == msg_ps->vb_ptr->value_type) &&
+           (en->set_test_a(request_id,&msg_ps->ext_object_def,
+                           msg_ps->vb_ptr->value_len,msg_ps->vb_ptr->value) != 0))
+      {
+        msg_ps->state = SNMP_MSG_SEARCH_OBJ;
+        msg_ps->vb_idx += 1;
+      }
+      else
+      {
+        en->set_test_pc(request_id,&msg_ps->ext_object_def);
+        /* bad value */
+        snmp_error_response(msg_ps,SNMP_ES_BADVALUE);
+      }
+    }
+    else
+    {
+      en->set_test_pc(request_id,&msg_ps->ext_object_def);
+      /* object not available for set */
+      snmp_error_response(msg_ps,SNMP_ES_NOSUCHNAME);
+    }
+  }
+  else if (msg_ps->state == SNMP_MSG_EXTERNAL_GET_OBJDEF_S)
+  {
+    struct mib_external_node *en;
+    struct snmp_name_ptr np;
+
+    /* get_object_def() answer*/
+    en = msg_ps->ext_mib_node;
+    np = msg_ps->ext_name_ptr;
+
+    /* translate answer into a known lifeform */
+    en->get_object_def_a(request_id, np.ident_len, np.ident, &msg_ps->ext_object_def);
+    if (msg_ps->ext_object_def.instance != MIB_OBJECT_NONE)
+    {
+      msg_ps->state = SNMP_MSG_EXTERNAL_SET_VALUE;
+      en->set_value_q(request_id, &msg_ps->ext_object_def,
+                      msg_ps->vb_ptr->value_len,msg_ps->vb_ptr->value);
+    }
+    else
+    {
+      en->get_object_def_pc(request_id, np.ident_len, np.ident);
+      /* set_value failed, object has disappeared for some odd reason?? */
+      snmp_error_response(msg_ps,SNMP_ES_GENERROR);
+    }
+  }
+  else if (msg_ps->state == SNMP_MSG_EXTERNAL_SET_VALUE)
+  {
+    struct mib_external_node *en;
+
+    /** set_value_a() */
+    en = msg_ps->ext_mib_node;
+    en->set_value_a(request_id, &msg_ps->ext_object_def,
+      msg_ps->vb_ptr->value_len, msg_ps->vb_ptr->value);
+
+    /** @todo use set_value_pc() if toobig */
+    msg_ps->state = SNMP_MSG_INTERNAL_SET_VALUE;
+    msg_ps->vb_idx += 1;
+  }
+
+  /* test all values before setting */
+  while ((msg_ps->state == SNMP_MSG_SEARCH_OBJ) &&
+         (msg_ps->vb_idx < msg_ps->invb.count))
+  {
+    struct mib_node *mn;
+    struct snmp_name_ptr np;
+
+    if (msg_ps->vb_idx == 0)
+    {
+      msg_ps->vb_ptr = msg_ps->invb.head;
+    }
+    else
+    {
+      msg_ps->vb_ptr = msg_ps->vb_ptr->next;
+    }
+    /** test object identifier for .iso.org.dod.internet prefix */
+    if (snmp_iso_prefix_tst(msg_ps->vb_ptr->ident_len,  msg_ps->vb_ptr->ident))
+    {
+      mn = snmp_search_tree((struct mib_node*)&internet, msg_ps->vb_ptr->ident_len - 4,
+                             msg_ps->vb_ptr->ident + 4, &np);
+      if (mn != NULL)
+      {
+        if (mn->node_type == MIB_NODE_EX)
+        {
+          /* external object */
+          struct mib_external_node *en = (struct mib_external_node*)mn;
+
+          msg_ps->state = SNMP_MSG_EXTERNAL_GET_OBJDEF;
+          /* save en && args in msg_ps!! */
+          msg_ps->ext_mib_node = en;
+          msg_ps->ext_name_ptr = np;
+
+          en->get_object_def_q(en->addr_inf, request_id, np.ident_len, np.ident);
+        }
+        else
+        {
+          /* internal object */
+          struct obj_def object_def;
+
+          msg_ps->state = SNMP_MSG_INTERNAL_GET_OBJDEF;
+          mn->get_object_def(np.ident_len, np.ident, &object_def);
+          if (object_def.instance != MIB_OBJECT_NONE)
+          {
+            mn = mn;
+          }
+          else
+          {
+            /* search failed, object id points to unknown object (nosuchname) */
+            mn = NULL;
+          }
+          if (mn != NULL)
+          {
+            msg_ps->state = SNMP_MSG_INTERNAL_SET_TEST;
+
+            if (object_def.access & MIB_ACCESS_WRITE)
+            {
+              if ((object_def.asn_type == msg_ps->vb_ptr->value_type) &&
+                  (mn->set_test(&object_def,msg_ps->vb_ptr->value_len,msg_ps->vb_ptr->value) != 0))
+              {
+                msg_ps->state = SNMP_MSG_SEARCH_OBJ;
+                msg_ps->vb_idx += 1;
+              }
+              else
+              {
+                /* bad value */
+                snmp_error_response(msg_ps,SNMP_ES_BADVALUE);
+              }
+            }
+            else
+            {
+              /* object not available for set */
+              snmp_error_response(msg_ps,SNMP_ES_NOSUCHNAME);
+            }
+          }
+        }
+      }
+    }
+    else
+    {
+      mn = NULL;
+    }
+    if (mn == NULL)
+    {
+      /* mn == NULL, noSuchName */
+      snmp_error_response(msg_ps,SNMP_ES_NOSUCHNAME);
+    }
+  }
+
+  if ((msg_ps->state == SNMP_MSG_SEARCH_OBJ) &&
+      (msg_ps->vb_idx == msg_ps->invb.count))
+  {
+    msg_ps->vb_idx = 0;
+    msg_ps->state = SNMP_MSG_INTERNAL_SET_VALUE;
+  }
+
+  /* set all values "atomically" (be as "atomic" as possible) */
+  while ((msg_ps->state == SNMP_MSG_INTERNAL_SET_VALUE) &&
+         (msg_ps->vb_idx < msg_ps->invb.count))
+  {
+    struct mib_node *mn;
+    struct snmp_name_ptr np;
+
+    if (msg_ps->vb_idx == 0)
+    {
+      msg_ps->vb_ptr = msg_ps->invb.head;
+    }
+    else
+    {
+      msg_ps->vb_ptr = msg_ps->vb_ptr->next;
+    }
+    /* skip iso prefix test, was done previously while settesting() */
+    mn = snmp_search_tree((struct mib_node*)&internet, msg_ps->vb_ptr->ident_len - 4,
+                           msg_ps->vb_ptr->ident + 4, &np);
+    /* check if object is still available
+       (e.g. external hot-plug thingy present?) */
+    if (mn != NULL)
+    {
+      if (mn->node_type == MIB_NODE_EX)
+      {
+        /* external object */
+        struct mib_external_node *en = (struct mib_external_node*)mn;
+
+        msg_ps->state = SNMP_MSG_EXTERNAL_GET_OBJDEF_S;
+        /* save en && args in msg_ps!! */
+        msg_ps->ext_mib_node = en;
+        msg_ps->ext_name_ptr = np;
+
+        en->get_object_def_q(en->addr_inf, request_id, np.ident_len, np.ident);
+      }
+      else
+      {
+        /* internal object */
+        struct obj_def object_def;
+
+        msg_ps->state = SNMP_MSG_INTERNAL_GET_OBJDEF_S;
+        mn->get_object_def(np.ident_len, np.ident, &object_def);
+        msg_ps->state = SNMP_MSG_INTERNAL_SET_VALUE;
+        mn->set_value(&object_def,msg_ps->vb_ptr->value_len,msg_ps->vb_ptr->value);
+        msg_ps->vb_idx += 1;
+      }
+    }
+  }
+  if ((msg_ps->state == SNMP_MSG_INTERNAL_SET_VALUE) &&
+      (msg_ps->vb_idx == msg_ps->invb.count))
+  {
+    /* simply echo the input if we can set it
+       @todo do we need to return the actual value?
+       e.g. if value is silently modified or behaves sticky? */
+    msg_ps->outvb = msg_ps->invb;
+    msg_ps->invb.head = NULL;
+    msg_ps->invb.tail = NULL;
+    msg_ps->invb.count = 0;
+    snmp_ok_response(msg_ps);
+  }
+}
+
+
+/**
+ * Handle one internal or external event.
+ * Called for one async event. (recv external/private answer)
+ *
+ * @param request_id identifies requests from 0 to (SNMP_CONCURRENT_REQUESTS-1)
+ */
+void
+snmp_msg_event(u8_t request_id)
+{
+  struct snmp_msg_pstat *msg_ps;
+
+  if (request_id < SNMP_CONCURRENT_REQUESTS)
+  {
+    msg_ps = &msg_input_list[request_id];
+    if (msg_ps->rt == SNMP_ASN1_PDU_GET_NEXT_REQ)
+    {
+      snmp_msg_getnext_event(request_id, msg_ps);
+    }
+    else if (msg_ps->rt == SNMP_ASN1_PDU_GET_REQ)
+    {
+      snmp_msg_get_event(request_id, msg_ps);
+    }
+    else if(msg_ps->rt == SNMP_ASN1_PDU_SET_REQ)
+    {
+      snmp_msg_set_event(request_id, msg_ps);
+    }
+  }
+}
+
+
+/* lwIP UDP receive callback function */
+static void
+snmp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port)
+{
+  struct snmp_msg_pstat *msg_ps;
+  u8_t req_idx;
+  err_t err_ret;
+  u16_t payload_len = p->tot_len;
+  u16_t payload_ofs = 0;
+  u16_t varbind_ofs = 0;
+
+  /* suppress unused argument warning */
+  LWIP_UNUSED_ARG(arg);
+
+  /* traverse input message process list, look for SNMP_MSG_EMPTY */
+  msg_ps = &msg_input_list[0];
+  req_idx = 0;
+  while ((req_idx < SNMP_CONCURRENT_REQUESTS) && (msg_ps->state != SNMP_MSG_EMPTY))
+  {
+    req_idx++;
+    msg_ps++;
+  }
+  if (req_idx == SNMP_CONCURRENT_REQUESTS)
+  {
+    /* exceeding number of concurrent requests */
+    pbuf_free(p);
+    return;
+  }
+
+  /* accepting request */
+  snmp_inc_snmpinpkts();
+  /* record used 'protocol control block' */
+  msg_ps->pcb = pcb;
+  /* source address (network order) */
+  msg_ps->sip = *addr;
+  /* source port (host order (lwIP oddity)) */
+  msg_ps->sp = port;
+
+  /* check total length, version, community, pdu type */
+  err_ret = snmp_pdu_header_check(p, payload_ofs, payload_len, &varbind_ofs, msg_ps);
+  /* Only accept requests and requests without error (be robust) */
+  /* Reject response and trap headers or error requests as input! */
+  if ((err_ret != ERR_OK) ||
+      ((msg_ps->rt != SNMP_ASN1_PDU_GET_REQ) &&
+       (msg_ps->rt != SNMP_ASN1_PDU_GET_NEXT_REQ) &&
+       (msg_ps->rt != SNMP_ASN1_PDU_SET_REQ)) ||
+      ((msg_ps->error_status != SNMP_ES_NOERROR) ||
+       (msg_ps->error_index != 0)) )
+  {
+    /* header check failed drop request silently, do not return error! */
+    pbuf_free(p);
+    LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_pdu_header_check() failed\n"));
+    return;
+  }
+  LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_recv ok, community %s\n", msg_ps->community));
+
+  /* Builds a list of variable bindings. Copy the varbinds from the pbuf
+    chain to glue them when these are divided over two or more pbuf's. */
+  err_ret = snmp_pdu_dec_varbindlist(p, varbind_ofs, &varbind_ofs, msg_ps);
+  /* we've decoded the incoming message, release input msg now */
+  pbuf_free(p);
+  if ((err_ret != ERR_OK) || (msg_ps->invb.count == 0))
+  {
+    /* varbind-list decode failed, or varbind list empty.
+       drop request silently, do not return error!
+       (errors are only returned for a specific varbind failure) */
+    LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_pdu_dec_varbindlist() failed\n"));
+    return;
+  }
+
+  msg_ps->error_status = SNMP_ES_NOERROR;
+  msg_ps->error_index = 0;
+  /* find object for each variable binding */
+  msg_ps->state = SNMP_MSG_SEARCH_OBJ;
+  /* first variable binding from list to inspect */
+  msg_ps->vb_idx = 0;
+
+  LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_recv varbind cnt=%"U16_F"\n",(u16_t)msg_ps->invb.count));
+
+  /* handle input event and as much objects as possible in one go */
+  snmp_msg_event(req_idx);
+}
+
+/**
+ * Checks and decodes incoming SNMP message header, logs header errors.
+ *
+ * @param p points to pbuf chain of SNMP message (UDP payload)
+ * @param ofs points to first octet of SNMP message
+ * @param pdu_len the length of the UDP payload
+ * @param ofs_ret returns the ofset of the variable bindings
+ * @param m_stat points to the current message request state return
+ * @return
+ * - ERR_OK SNMP header is sane and accepted
+ * - ERR_ARG SNMP header is either malformed or rejected
+ */
+static err_t
+snmp_pdu_header_check(struct pbuf *p, u16_t ofs, u16_t pdu_len, u16_t *ofs_ret, struct snmp_msg_pstat *m_stat)
+{
+  err_t derr;
+  u16_t len, ofs_base;
+  u8_t  len_octets;
+  u8_t  type;
+  s32_t version;
+
+  ofs_base = ofs;
+  snmp_asn1_dec_type(p, ofs, &type);
+  derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len);
+  if ((derr != ERR_OK) ||
+      (pdu_len != (1 + len_octets + len)) ||
+      (type != (SNMP_ASN1_UNIV | SNMP_ASN1_CONSTR | SNMP_ASN1_SEQ)))
+  {
+    snmp_inc_snmpinasnparseerrs();
+    return ERR_ARG;
+  }
+  ofs += (1 + len_octets);
+  snmp_asn1_dec_type(p, ofs, &type);
+  derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len);
+  if ((derr != ERR_OK) || (type != (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG)))
+  {
+    /* can't decode or no integer (version) */
+    snmp_inc_snmpinasnparseerrs();
+    return ERR_ARG;
+  }
+  derr = snmp_asn1_dec_s32t(p, ofs + 1 + len_octets, len, &version);
+  if (derr != ERR_OK)
+  {
+    /* can't decode */
+    snmp_inc_snmpinasnparseerrs();
+    return ERR_ARG;
+  }
+  if (version != 0)
+  {
+    /* not version 1 */
+    snmp_inc_snmpinbadversions();
+    return ERR_ARG;
+  }
+  ofs += (1 + len_octets + len);
+  snmp_asn1_dec_type(p, ofs, &type);
+  derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len);
+  if ((derr != ERR_OK) || (type != (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR)))
+  {
+    /* can't decode or no octet string (community) */
+    snmp_inc_snmpinasnparseerrs();
+    return ERR_ARG;
+  }
+  derr = snmp_asn1_dec_raw(p, ofs + 1 + len_octets, len, SNMP_COMMUNITY_STR_LEN, m_stat->community);
+  if (derr != ERR_OK)
+  {
+    snmp_inc_snmpinasnparseerrs();
+    return ERR_ARG;
+  }
+  /* add zero terminator */
+  len = ((len < (SNMP_COMMUNITY_STR_LEN))?(len):(SNMP_COMMUNITY_STR_LEN));
+  m_stat->community[len] = 0;
+  m_stat->com_strlen = (u8_t)len;
+  if (strncmp(snmp_publiccommunity, (const char*)m_stat->community, SNMP_COMMUNITY_STR_LEN) != 0)
+  {
+    /** @todo: move this if we need to check more names */
+    snmp_inc_snmpinbadcommunitynames();
+    snmp_authfail_trap();
+    return ERR_ARG;
+  }
+  ofs += (1 + len_octets + len);
+  snmp_asn1_dec_type(p, ofs, &type);
+  derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len);
+  if (derr != ERR_OK)
+  {
+    snmp_inc_snmpinasnparseerrs();
+    return ERR_ARG;
+  }
+  switch(type)
+  {
+    case (SNMP_ASN1_CONTXT | SNMP_ASN1_CONSTR | SNMP_ASN1_PDU_GET_REQ):
+      /* GetRequest PDU */
+      snmp_inc_snmpingetrequests();
+      derr = ERR_OK;
+      break;
+    case (SNMP_ASN1_CONTXT | SNMP_ASN1_CONSTR | SNMP_ASN1_PDU_GET_NEXT_REQ):
+      /* GetNextRequest PDU */
+      snmp_inc_snmpingetnexts();
+      derr = ERR_OK;
+      break;
+    case (SNMP_ASN1_CONTXT | SNMP_ASN1_CONSTR | SNMP_ASN1_PDU_GET_RESP):
+      /* GetResponse PDU */
+      snmp_inc_snmpingetresponses();
+      derr = ERR_ARG;
+      break;
+    case (SNMP_ASN1_CONTXT | SNMP_ASN1_CONSTR | SNMP_ASN1_PDU_SET_REQ):
+      /* SetRequest PDU */
+      snmp_inc_snmpinsetrequests();
+      derr = ERR_OK;
+      break;
+    case (SNMP_ASN1_CONTXT | SNMP_ASN1_CONSTR | SNMP_ASN1_PDU_TRAP):
+      /* Trap PDU */
+      snmp_inc_snmpintraps();
+      derr = ERR_ARG;
+      break;
+    default:
+      snmp_inc_snmpinasnparseerrs();
+      derr = ERR_ARG;
+      break;
+  }
+  if (derr != ERR_OK)
+  {
+    /* unsupported input PDU for this agent (no parse error) */
+    return ERR_ARG;
+  }
+  m_stat->rt = type & 0x1F;
+  ofs += (1 + len_octets);
+  if (len != (pdu_len - (ofs - ofs_base)))
+  {
+    /* decoded PDU length does not equal actual payload length */
+    snmp_inc_snmpinasnparseerrs();
+    return ERR_ARG;
+  }
+  snmp_asn1_dec_type(p, ofs, &type);
+  derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len);
+  if ((derr != ERR_OK) || (type != (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG)))
+  {
+    /* can't decode or no integer (request ID) */
+    snmp_inc_snmpinasnparseerrs();
+    return ERR_ARG;
+  }
+  derr = snmp_asn1_dec_s32t(p, ofs + 1 + len_octets, len, &m_stat->rid);
+  if (derr != ERR_OK)
+  {
+    /* can't decode */
+    snmp_inc_snmpinasnparseerrs();
+    return ERR_ARG;
+  }
+  ofs += (1 + len_octets + len);
+  snmp_asn1_dec_type(p, ofs, &type);
+  derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len);
+  if ((derr != ERR_OK) || (type != (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG)))
+  {
+    /* can't decode or no integer (error-status) */
+    snmp_inc_snmpinasnparseerrs();
+    return ERR_ARG;
+  }
+  /* must be noError (0) for incoming requests.
+     log errors for mib-2 completeness and for debug purposes */
+  derr = snmp_asn1_dec_s32t(p, ofs + 1 + len_octets, len, &m_stat->error_status);
+  if (derr != ERR_OK)
+  {
+    /* can't decode */
+    snmp_inc_snmpinasnparseerrs();
+    return ERR_ARG;
+  }
+  switch (m_stat->error_status)
+  {
+    case SNMP_ES_TOOBIG:
+      snmp_inc_snmpintoobigs();
+      break;
+    case SNMP_ES_NOSUCHNAME:
+      snmp_inc_snmpinnosuchnames();
+      break;
+    case SNMP_ES_BADVALUE:
+      snmp_inc_snmpinbadvalues();
+      break;
+    case SNMP_ES_READONLY:
+      snmp_inc_snmpinreadonlys();
+      break;
+    case SNMP_ES_GENERROR:
+      snmp_inc_snmpingenerrs();
+      break;
+  }
+  ofs += (1 + len_octets + len);
+  snmp_asn1_dec_type(p, ofs, &type);
+  derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len);
+  if ((derr != ERR_OK) || (type != (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG)))
+  {
+    /* can't decode or no integer (error-index) */
+    snmp_inc_snmpinasnparseerrs();
+    return ERR_ARG;
+  }
+  /* must be 0 for incoming requests.
+     decode anyway to catch bad integers (and dirty tricks) */
+  derr = snmp_asn1_dec_s32t(p, ofs + 1 + len_octets, len, &m_stat->error_index);
+  if (derr != ERR_OK)
+  {
+    /* can't decode */
+    snmp_inc_snmpinasnparseerrs();
+    return ERR_ARG;
+  }
+  ofs += (1 + len_octets + len);
+  *ofs_ret = ofs;
+  return ERR_OK;
+}
+
+static err_t
+snmp_pdu_dec_varbindlist(struct pbuf *p, u16_t ofs, u16_t *ofs_ret, struct snmp_msg_pstat *m_stat)
+{
+  err_t derr;
+  u16_t len, vb_len;
+  u8_t  len_octets;
+  u8_t type;
+
+  /* variable binding list */
+  snmp_asn1_dec_type(p, ofs, &type);
+  derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &vb_len);
+  if ((derr != ERR_OK) ||
+      (type != (SNMP_ASN1_UNIV | SNMP_ASN1_CONSTR | SNMP_ASN1_SEQ)))
+  {
+    snmp_inc_snmpinasnparseerrs();
+    return ERR_ARG;
+  }
+  ofs += (1 + len_octets);
+
+  /* start with empty list */
+  m_stat->invb.count = 0;
+  m_stat->invb.head = NULL;
+  m_stat->invb.tail = NULL;
+
+  while (vb_len > 0)
+  {
+    struct snmp_obj_id oid, oid_value;
+    struct snmp_varbind *vb;
+
+    snmp_asn1_dec_type(p, ofs, &type);
+    derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len);
+    if ((derr != ERR_OK) ||
+        (type != (SNMP_ASN1_UNIV | SNMP_ASN1_CONSTR | SNMP_ASN1_SEQ)) ||
+        (len == 0) || (len > vb_len))
+    {
+      snmp_inc_snmpinasnparseerrs();
+      /* free varbinds (if available) */
+      snmp_varbind_list_free(&m_stat->invb);
+      return ERR_ARG;
+    }
+    ofs += (1 + len_octets);
+    vb_len -= (1 + len_octets);
+
+    snmp_asn1_dec_type(p, ofs, &type);
+    derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len);
+    if ((derr != ERR_OK) || (type != (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OBJ_ID)))
+    {
+      /* can't decode object name length */
+      snmp_inc_snmpinasnparseerrs();
+      /* free varbinds (if available) */
+      snmp_varbind_list_free(&m_stat->invb);
+      return ERR_ARG;
+    }
+    derr = snmp_asn1_dec_oid(p, ofs + 1 + len_octets, len, &oid);
+    if (derr != ERR_OK)
+    {
+      /* can't decode object name */
+      snmp_inc_snmpinasnparseerrs();
+      /* free varbinds (if available) */
+      snmp_varbind_list_free(&m_stat->invb);
+      return ERR_ARG;
+    }
+    ofs += (1 + len_octets + len);
+    vb_len -= (1 + len_octets + len);
+
+    snmp_asn1_dec_type(p, ofs, &type);
+    derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len);
+    if (derr != ERR_OK)
+    {
+      /* can't decode object value length */
+      snmp_inc_snmpinasnparseerrs();
+      /* free varbinds (if available) */
+      snmp_varbind_list_free(&m_stat->invb);
+      return ERR_ARG;
+    }
+
+    switch (type)
+    {
+      case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG):
+        vb = snmp_varbind_alloc(&oid, type, sizeof(s32_t));
+        if (vb != NULL)
+        {
+          s32_t *vptr = (s32_t*)vb->value;
+
+          derr = snmp_asn1_dec_s32t(p, ofs + 1 + len_octets, len, vptr);
+          snmp_varbind_tail_add(&m_stat->invb, vb);
+        }
+        else
+        {
+          derr = ERR_ARG;
+        }
+        break;
+      case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_COUNTER):
+      case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_GAUGE):
+      case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_TIMETICKS):
+        vb = snmp_varbind_alloc(&oid, type, sizeof(u32_t));
+        if (vb != NULL)
+        {
+          u32_t *vptr = (u32_t*)vb->value;
+
+          derr = snmp_asn1_dec_u32t(p, ofs + 1 + len_octets, len, vptr);
+          snmp_varbind_tail_add(&m_stat->invb, vb);
+        }
+        else
+        {
+          derr = ERR_ARG;
+        }
+        break;
+      case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR):
+      case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_OPAQUE):
+        LWIP_ASSERT("invalid length", len <= 0xff);
+        vb = snmp_varbind_alloc(&oid, type, (u8_t)len);
+        if (vb != NULL)
+        {
+          derr = snmp_asn1_dec_raw(p, ofs + 1 + len_octets, len, vb->value_len, (u8_t*)vb->value);
+          snmp_varbind_tail_add(&m_stat->invb, vb);
+        }
+        else
+        {
+          derr = ERR_ARG;
+        }
+        break;
+      case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_NUL):
+        vb = snmp_varbind_alloc(&oid, type, 0);
+        if (vb != NULL)
+        {
+          snmp_varbind_tail_add(&m_stat->invb, vb);
+          derr = ERR_OK;
+        }
+        else
+        {
+          derr = ERR_ARG;
+        }
+        break;
+      case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OBJ_ID):
+        derr = snmp_asn1_dec_oid(p, ofs + 1 + len_octets, len, &oid_value);
+        if (derr == ERR_OK)
+        {
+          vb = snmp_varbind_alloc(&oid, type, oid_value.len * sizeof(s32_t));
+          if (vb != NULL)
+          {
+            u8_t i = oid_value.len;
+            s32_t *vptr = (s32_t*)vb->value;
+
+            while(i > 0)
+            {
+              i--;
+              vptr[i] = oid_value.id[i];
+            }
+            snmp_varbind_tail_add(&m_stat->invb, vb);
+            derr = ERR_OK;
+          }
+          else
+          {
+            derr = ERR_ARG;
+          }
+        }
+        break;
+      case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_IPADDR):
+        if (len == 4)
+        {
+          /* must be exactly 4 octets! */
+          vb = snmp_varbind_alloc(&oid, type, 4);
+          if (vb != NULL)
+          {
+            derr = snmp_asn1_dec_raw(p, ofs + 1 + len_octets, len, vb->value_len, (u8_t*)vb->value);
+            snmp_varbind_tail_add(&m_stat->invb, vb);
+          }
+          else
+          {
+            derr = ERR_ARG;
+          }
+        }
+        else
+        {
+          derr = ERR_ARG;
+        }
+        break;
+      default:
+        derr = ERR_ARG;
+        break;
+    }
+    if (derr != ERR_OK)
+    {
+      snmp_inc_snmpinasnparseerrs();
+      /* free varbinds (if available) */
+      snmp_varbind_list_free(&m_stat->invb);
+      return ERR_ARG;
+    }
+    ofs += (1 + len_octets + len);
+    vb_len -= (1 + len_octets + len);
+  }
+
+  if (m_stat->rt == SNMP_ASN1_PDU_SET_REQ)
+  {
+    snmp_add_snmpintotalsetvars(m_stat->invb.count);
+  }
+  else
+  {
+    snmp_add_snmpintotalreqvars(m_stat->invb.count);
+  }
+
+  *ofs_ret = ofs;
+  return ERR_OK;
+}
+
+struct snmp_varbind*
+snmp_varbind_alloc(struct snmp_obj_id *oid, u8_t type, u8_t len)
+{
+  struct snmp_varbind *vb;
+
+  vb = (struct snmp_varbind *)memp_malloc(MEMP_SNMP_VARBIND);
+  LWIP_ASSERT("vb != NULL",vb != NULL);
+  if (vb != NULL)
+  {
+    u8_t i;
+
+    vb->next = NULL;
+    vb->prev = NULL;
+    i = oid->len;
+    vb->ident_len = i;
+    if (i > 0)
+    {
+      LWIP_ASSERT("SNMP_MAX_TREE_DEPTH is configured too low", i <= SNMP_MAX_TREE_DEPTH);
+      /* allocate array of s32_t for our object identifier */
+      vb->ident = (s32_t*)memp_malloc(MEMP_SNMP_VALUE);
+      LWIP_ASSERT("vb->ident != NULL",vb->ident != NULL);
+      if (vb->ident == NULL)
+      {
+        memp_free(MEMP_SNMP_VARBIND, vb);
+        return NULL;
+      }
+      while(i > 0)
+      {
+        i--;
+        vb->ident[i] = oid->id[i];
+      }
+    }
+    else
+    {
+      /* i == 0, pass zero length object identifier */
+      vb->ident = NULL;
+    }
+    vb->value_type = type;
+    vb->value_len = len;
+    if (len > 0)
+    {
+      LWIP_ASSERT("SNMP_MAX_OCTET_STRING_LEN is configured too low", vb->value_len <= SNMP_MAX_VALUE_SIZE);
+      /* allocate raw bytes for our object value */
+      vb->value = memp_malloc(MEMP_SNMP_VALUE);
+      LWIP_ASSERT("vb->value != NULL",vb->value != NULL);
+      if (vb->value == NULL)
+      {
+        if (vb->ident != NULL)
+        {
+          memp_free(MEMP_SNMP_VALUE, vb->ident);
+        }
+        memp_free(MEMP_SNMP_VARBIND, vb);
+        return NULL;
+      }
+    }
+    else
+    {
+      /* ASN1_NUL type, or zero length ASN1_OC_STR */
+      vb->value = NULL;
+    }
+  }
+  return vb;
+}
+
+void
+snmp_varbind_free(struct snmp_varbind *vb)
+{
+  if (vb->value != NULL )
+  {
+    memp_free(MEMP_SNMP_VALUE, vb->value);
+  }
+  if (vb->ident != NULL )
+  {
+    memp_free(MEMP_SNMP_VALUE, vb->ident);
+  }
+  memp_free(MEMP_SNMP_VARBIND, vb);
+}
+
+void
+snmp_varbind_list_free(struct snmp_varbind_root *root)
+{
+  struct snmp_varbind *vb, *prev;
+
+  vb = root->tail;
+  while ( vb != NULL )
+  {
+    prev = vb->prev;
+    snmp_varbind_free(vb);
+    vb = prev;
+  }
+  root->count = 0;
+  root->head = NULL;
+  root->tail = NULL;
+}
+
+void
+snmp_varbind_tail_add(struct snmp_varbind_root *root, struct snmp_varbind *vb)
+{
+  if (root->count == 0)
+  {
+    /* add first varbind to list */
+    root->head = vb;
+    root->tail = vb;
+  }
+  else
+  {
+    /* add nth varbind to list tail */
+    root->tail->next = vb;
+    vb->prev = root->tail;
+    root->tail = vb;
+  }
+  root->count += 1;
+}
+
+struct snmp_varbind*
+snmp_varbind_tail_remove(struct snmp_varbind_root *root)
+{
+  struct snmp_varbind* vb;
+
+  if (root->count > 0)
+  {
+    /* remove tail varbind */
+    vb = root->tail;
+    root->tail = vb->prev;
+    vb->prev->next = NULL;
+    root->count -= 1;
+  }
+  else
+  {
+    /* nothing to remove */
+    vb = NULL;
+  }
+  return vb;
+}
+
+#endif /* LWIP_SNMP */
diff --git a/core/lwip/src/core/snmp/msg_out.c b/core/lwip/src/core/snmp/msg_out.c
new file mode 100644
index 00000000..4778bee6
--- /dev/null
+++ b/core/lwip/src/core/snmp/msg_out.c
@@ -0,0 +1,681 @@
+/**
+ * @file
+ * SNMP output message processing (RFC1157).
+ *
+ * Output responses and traps are build in two passes:
+ *
+ * Pass 0: iterate over the output message backwards to determine encoding lengths
+ * Pass 1: the actual forward encoding of internal form into ASN1
+ *
+ * The single-pass encoding method described by Comer & Stevens
+ * requires extra buffer space and copying for reversal of the packet.
+ * The buffer requirement can be prohibitively large for big payloads
+ * (>= 484) therefore we use the two encoding passes.
+ */
+
+/*
+ * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * Author: Christiaan Simons <christiaan.simons@axon.tv>
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/udp.h"
+#include "lwip/netif.h"
+#include "lwip/snmp.h"
+#include "lwip/snmp_asn1.h"
+#include "lwip/snmp_msg.h"
+
+struct snmp_trap_dst
+{
+  /* destination IP address in network order */
+  ip_addr_t dip;
+  /* set to 0 when disabled, >0 when enabled */
+  u8_t enable;
+};
+struct snmp_trap_dst trap_dst[SNMP_TRAP_DESTINATIONS];
+
+/** TRAP message structure */
+struct snmp_msg_trap trap_msg;
+
+static u16_t snmp_resp_header_sum(struct snmp_msg_pstat *m_stat, u16_t vb_len);
+static u16_t snmp_trap_header_sum(struct snmp_msg_trap *m_trap, u16_t vb_len);
+static u16_t snmp_varbind_list_sum(struct snmp_varbind_root *root);
+
+static u16_t snmp_resp_header_enc(struct snmp_msg_pstat *m_stat, struct pbuf *p);
+static u16_t snmp_trap_header_enc(struct snmp_msg_trap *m_trap, struct pbuf *p);
+static u16_t snmp_varbind_list_enc(struct snmp_varbind_root *root, struct pbuf *p, u16_t ofs);
+
+/**
+ * Sets enable switch for this trap destination.
+ * @param dst_idx index in 0 .. SNMP_TRAP_DESTINATIONS-1
+ * @param enable switch if 0 destination is disabled >0 enabled.
+ */
+void
+snmp_trap_dst_enable(u8_t dst_idx, u8_t enable)
+{
+  if (dst_idx < SNMP_TRAP_DESTINATIONS)
+  {
+    trap_dst[dst_idx].enable = enable;
+  }
+}
+
+/**
+ * Sets IPv4 address for this trap destination.
+ * @param dst_idx index in 0 .. SNMP_TRAP_DESTINATIONS-1
+ * @param dst IPv4 address in host order.
+ */
+void
+snmp_trap_dst_ip_set(u8_t dst_idx, ip_addr_t *dst)
+{
+  if (dst_idx < SNMP_TRAP_DESTINATIONS)
+  {
+    ip_addr_set(&trap_dst[dst_idx].dip, dst);
+  }
+}
+
+/**
+ * Sends a 'getresponse' message to the request originator.
+ *
+ * @param m_stat points to the current message request state source
+ * @return ERR_OK when success, ERR_MEM if we're out of memory
+ *
+ * @note the caller is responsible for filling in outvb in the m_stat
+ * and provide error-status and index (except for tooBig errors) ...
+ */
+err_t
+snmp_send_response(struct snmp_msg_pstat *m_stat)
+{
+  struct snmp_varbind_root emptyvb = {NULL, NULL, 0, 0, 0};
+  struct pbuf *p;
+  u16_t tot_len;
+  err_t err;
+
+  /* pass 0, calculate length fields */
+  tot_len = snmp_varbind_list_sum(&m_stat->outvb);
+  tot_len = snmp_resp_header_sum(m_stat, tot_len);
+
+  /* try allocating pbuf(s) for complete response */
+  p = pbuf_alloc(PBUF_TRANSPORT, tot_len, PBUF_POOL);
+  if (p == NULL)
+  {
+    LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_snd_response() tooBig\n"));
+
+    /* can't construct reply, return error-status tooBig */
+    m_stat->error_status = SNMP_ES_TOOBIG;
+    m_stat->error_index = 0;
+    /* pass 0, recalculate lengths, for empty varbind-list */
+    tot_len = snmp_varbind_list_sum(&emptyvb);
+    tot_len = snmp_resp_header_sum(m_stat, tot_len);
+    /* retry allocation once for header and empty varbind-list */
+    p = pbuf_alloc(PBUF_TRANSPORT, tot_len, PBUF_POOL);
+  }
+  if (p != NULL)
+  {
+    /* first pbuf alloc try or retry alloc success */
+    u16_t ofs;
+
+    LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_snd_response() p != NULL\n"));
+
+    /* pass 1, size error, encode packet ino the pbuf(s) */
+    ofs = snmp_resp_header_enc(m_stat, p);
+    if (m_stat->error_status == SNMP_ES_TOOBIG)
+    {
+      snmp_varbind_list_enc(&emptyvb, p, ofs);
+    }
+    else
+    {
+      snmp_varbind_list_enc(&m_stat->outvb, p, ofs);
+    }
+
+    switch (m_stat->error_status)
+    {
+      case SNMP_ES_TOOBIG:
+        snmp_inc_snmpouttoobigs();
+        break;
+      case SNMP_ES_NOSUCHNAME:
+        snmp_inc_snmpoutnosuchnames();
+        break;
+      case SNMP_ES_BADVALUE:
+        snmp_inc_snmpoutbadvalues();
+        break;
+      case SNMP_ES_GENERROR:
+        snmp_inc_snmpoutgenerrs();
+        break;
+    }
+    snmp_inc_snmpoutgetresponses();
+    snmp_inc_snmpoutpkts();
+
+    /** @todo do we need separate rx and tx pcbs for threaded case? */
+    /** connect to the originating source */
+    udp_connect(m_stat->pcb, &m_stat->sip, m_stat->sp);
+    err = udp_send(m_stat->pcb, p);
+    if (err == ERR_MEM)
+    {
+      /** @todo release some memory, retry and return tooBig? tooMuchHassle? */
+      err = ERR_MEM;
+    }
+    else
+    {
+      err = ERR_OK;
+    }
+    /** disassociate remote address and port with this pcb */
+    udp_disconnect(m_stat->pcb);
+
+    pbuf_free(p);
+    LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_snd_response() done\n"));
+    return err;
+  }
+  else
+  {
+    /* first pbuf alloc try or retry alloc failed
+       very low on memory, couldn't return tooBig */
+    return ERR_MEM;
+  }
+}
+
+
+/**
+ * Sends an generic or enterprise specific trap message.
+ *
+ * @param generic_trap is the trap code
+ * @param eoid points to enterprise object identifier
+ * @param specific_trap used for enterprise traps when generic_trap == 6
+ * @return ERR_OK when success, ERR_MEM if we're out of memory
+ *
+ * @note the caller is responsible for filling in outvb in the trap_msg
+ * @note the use of the enterpise identifier field
+ * is per RFC1215.
+ * Use .iso.org.dod.internet.mgmt.mib-2.snmp for generic traps
+ * and .iso.org.dod.internet.private.enterprises.yourenterprise
+ * (sysObjectID) for specific traps.
+ */
+err_t
+snmp_send_trap(s8_t generic_trap, struct snmp_obj_id *eoid, s32_t specific_trap)
+{
+  struct snmp_trap_dst *td;
+  struct netif *dst_if;
+  ip_addr_t dst_ip;
+  struct pbuf *p;
+  u16_t i,tot_len;
+
+  for (i=0, td = &trap_dst[0]; i<SNMP_TRAP_DESTINATIONS; i++, td++)
+  {
+    if ((td->enable != 0) && !ip_addr_isany(&td->dip))
+    {
+      /* network order trap destination */
+      ip_addr_copy(trap_msg.dip, td->dip);
+      /* lookup current source address for this dst */
+      dst_if = ip_route(&td->dip);
+      ip_addr_copy(dst_ip, dst_if->ip_addr);
+      /* @todo: what about IPv6? */
+      trap_msg.sip_raw[0] = ip4_addr1(&dst_ip);
+      trap_msg.sip_raw[1] = ip4_addr2(&dst_ip);
+      trap_msg.sip_raw[2] = ip4_addr3(&dst_ip);
+      trap_msg.sip_raw[3] = ip4_addr4(&dst_ip);
+      trap_msg.gen_trap = generic_trap;
+      trap_msg.spc_trap = specific_trap;
+      if (generic_trap == SNMP_GENTRAP_ENTERPRISESPC)
+      {
+        /* enterprise-Specific trap */
+        trap_msg.enterprise = eoid;
+      }
+      else
+      {
+        /* generic (MIB-II) trap */
+        snmp_get_snmpgrpid_ptr(&trap_msg.enterprise);
+      }
+      snmp_get_sysuptime(&trap_msg.ts);
+
+      /* pass 0, calculate length fields */
+      tot_len = snmp_varbind_list_sum(&trap_msg.outvb);
+      tot_len = snmp_trap_header_sum(&trap_msg, tot_len);
+
+      /* allocate pbuf(s) */
+      p = pbuf_alloc(PBUF_TRANSPORT, tot_len, PBUF_POOL);
+      if (p != NULL)
+      {
+        u16_t ofs;
+
+        /* pass 1, encode packet ino the pbuf(s) */
+        ofs = snmp_trap_header_enc(&trap_msg, p);
+        snmp_varbind_list_enc(&trap_msg.outvb, p, ofs);
+
+        snmp_inc_snmpouttraps();
+        snmp_inc_snmpoutpkts();
+
+        /** send to the TRAP destination */
+        udp_sendto(trap_msg.pcb, p, &trap_msg.dip, SNMP_TRAP_PORT);
+
+        pbuf_free(p);
+      }
+      else
+      {
+        return ERR_MEM;
+      }
+    }
+  }
+  return ERR_OK;
+}
+
+void
+snmp_coldstart_trap(void)
+{
+  trap_msg.outvb.head = NULL;
+  trap_msg.outvb.tail = NULL;
+  trap_msg.outvb.count = 0;
+  snmp_send_trap(SNMP_GENTRAP_COLDSTART, NULL, 0);
+}
+
+void
+snmp_authfail_trap(void)
+{
+  u8_t enable;
+  snmp_get_snmpenableauthentraps(&enable);
+  if (enable == 1)
+  {
+    trap_msg.outvb.head = NULL;
+    trap_msg.outvb.tail = NULL;
+    trap_msg.outvb.count = 0;
+    snmp_send_trap(SNMP_GENTRAP_AUTHFAIL, NULL, 0);
+  }
+}
+
+/**
+ * Sums response header field lengths from tail to head and
+ * returns resp_header_lengths for second encoding pass.
+ *
+ * @param vb_len varbind-list length
+ * @param rhl points to returned header lengths
+ * @return the required lenght for encoding the response header
+ */
+static u16_t
+snmp_resp_header_sum(struct snmp_msg_pstat *m_stat, u16_t vb_len)
+{
+  u16_t tot_len;
+  struct snmp_resp_header_lengths *rhl;
+
+  rhl = &m_stat->rhl;
+  tot_len = vb_len;
+  snmp_asn1_enc_s32t_cnt(m_stat->error_index, &rhl->erridxlen);
+  snmp_asn1_enc_length_cnt(rhl->erridxlen, &rhl->erridxlenlen);
+  tot_len += 1 + rhl->erridxlenlen + rhl->erridxlen;
+
+  snmp_asn1_enc_s32t_cnt(m_stat->error_status, &rhl->errstatlen);
+  snmp_asn1_enc_length_cnt(rhl->errstatlen, &rhl->errstatlenlen);
+  tot_len += 1 + rhl->errstatlenlen + rhl->errstatlen;
+
+  snmp_asn1_enc_s32t_cnt(m_stat->rid, &rhl->ridlen);
+  snmp_asn1_enc_length_cnt(rhl->ridlen, &rhl->ridlenlen);
+  tot_len += 1 + rhl->ridlenlen + rhl->ridlen;
+
+  rhl->pdulen = tot_len;
+  snmp_asn1_enc_length_cnt(rhl->pdulen, &rhl->pdulenlen);
+  tot_len += 1 + rhl->pdulenlen;
+
+  rhl->comlen = m_stat->com_strlen;
+  snmp_asn1_enc_length_cnt(rhl->comlen, &rhl->comlenlen);
+  tot_len += 1 + rhl->comlenlen + rhl->comlen;
+
+  snmp_asn1_enc_s32t_cnt(snmp_version, &rhl->verlen);
+  snmp_asn1_enc_length_cnt(rhl->verlen, &rhl->verlenlen);
+  tot_len += 1 + rhl->verlen + rhl->verlenlen;
+
+  rhl->seqlen = tot_len;
+  snmp_asn1_enc_length_cnt(rhl->seqlen, &rhl->seqlenlen);
+  tot_len += 1 + rhl->seqlenlen;
+
+  return tot_len;
+}
+
+/**
+ * Sums trap header field lengths from tail to head and
+ * returns trap_header_lengths for second encoding pass.
+ *
+ * @param vb_len varbind-list length
+ * @param thl points to returned header lengths
+ * @return the required lenght for encoding the trap header
+ */
+static u16_t
+snmp_trap_header_sum(struct snmp_msg_trap *m_trap, u16_t vb_len)
+{
+  u16_t tot_len;
+  struct snmp_trap_header_lengths *thl;
+
+  thl = &m_trap->thl;
+  tot_len = vb_len;
+
+  snmp_asn1_enc_u32t_cnt(m_trap->ts, &thl->tslen);
+  snmp_asn1_enc_length_cnt(thl->tslen, &thl->tslenlen);
+  tot_len += 1 + thl->tslen + thl->tslenlen;
+
+  snmp_asn1_enc_s32t_cnt(m_trap->spc_trap, &thl->strplen);
+  snmp_asn1_enc_length_cnt(thl->strplen, &thl->strplenlen);
+  tot_len += 1 + thl->strplen + thl->strplenlen;
+
+  snmp_asn1_enc_s32t_cnt(m_trap->gen_trap, &thl->gtrplen);
+  snmp_asn1_enc_length_cnt(thl->gtrplen, &thl->gtrplenlen);
+  tot_len += 1 + thl->gtrplen + thl->gtrplenlen;
+
+  thl->aaddrlen = 4;
+  snmp_asn1_enc_length_cnt(thl->aaddrlen, &thl->aaddrlenlen);
+  tot_len += 1 + thl->aaddrlen + thl->aaddrlenlen;
+
+  snmp_asn1_enc_oid_cnt(m_trap->enterprise->len, &m_trap->enterprise->id[0], &thl->eidlen);
+  snmp_asn1_enc_length_cnt(thl->eidlen, &thl->eidlenlen);
+  tot_len += 1 + thl->eidlen + thl->eidlenlen;
+
+  thl->pdulen = tot_len;
+  snmp_asn1_enc_length_cnt(thl->pdulen, &thl->pdulenlen);
+  tot_len += 1 + thl->pdulenlen;
+
+  thl->comlen = sizeof(snmp_publiccommunity) - 1;
+  snmp_asn1_enc_length_cnt(thl->comlen, &thl->comlenlen);
+  tot_len += 1 + thl->comlenlen + thl->comlen;
+
+  snmp_asn1_enc_s32t_cnt(snmp_version, &thl->verlen);
+  snmp_asn1_enc_length_cnt(thl->verlen, &thl->verlenlen);
+  tot_len += 1 + thl->verlen + thl->verlenlen;
+
+  thl->seqlen = tot_len;
+  snmp_asn1_enc_length_cnt(thl->seqlen, &thl->seqlenlen);
+  tot_len += 1 + thl->seqlenlen;
+
+  return tot_len;
+}
+
+/**
+ * Sums varbind lengths from tail to head and
+ * annotates lengths in varbind for second encoding pass.
+ *
+ * @param root points to the root of the variable binding list
+ * @return the required lenght for encoding the variable bindings
+ */
+static u16_t
+snmp_varbind_list_sum(struct snmp_varbind_root *root)
+{
+  struct snmp_varbind *vb;
+  u32_t *uint_ptr;
+  s32_t *sint_ptr;
+  u16_t tot_len;
+
+  tot_len = 0;
+  vb = root->tail;
+  while ( vb != NULL )
+  {
+    /* encoded value lenght depends on type */
+    switch (vb->value_type)
+    {
+      case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG):
+        sint_ptr = (s32_t*)vb->value;
+        snmp_asn1_enc_s32t_cnt(*sint_ptr, &vb->vlen);
+        break;
+      case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_COUNTER):
+      case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_GAUGE):
+      case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_TIMETICKS):
+        uint_ptr = (u32_t*)vb->value;
+        snmp_asn1_enc_u32t_cnt(*uint_ptr, &vb->vlen);
+        break;
+      case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR):
+      case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_NUL):
+      case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_IPADDR):
+      case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_OPAQUE):
+        vb->vlen = vb->value_len;
+        break;
+      case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OBJ_ID):
+        sint_ptr = (s32_t*)vb->value;
+        snmp_asn1_enc_oid_cnt(vb->value_len / sizeof(s32_t), sint_ptr, &vb->vlen);
+        break;
+      default:
+        /* unsupported type */
+        vb->vlen = 0;
+        break;
+    };
+    /* encoding length of value length field */
+    snmp_asn1_enc_length_cnt(vb->vlen, &vb->vlenlen);
+    snmp_asn1_enc_oid_cnt(vb->ident_len, vb->ident, &vb->olen);
+    snmp_asn1_enc_length_cnt(vb->olen, &vb->olenlen);
+
+    vb->seqlen = 1 + vb->vlenlen + vb->vlen;
+    vb->seqlen += 1 + vb->olenlen + vb->olen;
+    snmp_asn1_enc_length_cnt(vb->seqlen, &vb->seqlenlen);
+
+    /* varbind seq */
+    tot_len += 1 + vb->seqlenlen + vb->seqlen;
+
+    vb = vb->prev;
+  }
+
+  /* varbind-list seq */
+  root->seqlen = tot_len;
+  snmp_asn1_enc_length_cnt(root->seqlen, &root->seqlenlen);
+  tot_len += 1 + root->seqlenlen;
+
+  return tot_len;
+}
+
+/**
+ * Encodes response header from head to tail.
+ */
+static u16_t
+snmp_resp_header_enc(struct snmp_msg_pstat *m_stat, struct pbuf *p)
+{
+  u16_t ofs;
+
+  ofs = 0;
+  snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_CONSTR | SNMP_ASN1_SEQ));
+  ofs += 1;
+  snmp_asn1_enc_length(p, ofs, m_stat->rhl.seqlen);
+  ofs += m_stat->rhl.seqlenlen;
+
+  snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG));
+  ofs += 1;
+  snmp_asn1_enc_length(p, ofs, m_stat->rhl.verlen);
+  ofs += m_stat->rhl.verlenlen;
+  snmp_asn1_enc_s32t(p, ofs, m_stat->rhl.verlen, snmp_version);
+  ofs += m_stat->rhl.verlen;
+
+  snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR));
+  ofs += 1;
+  snmp_asn1_enc_length(p, ofs, m_stat->rhl.comlen);
+  ofs += m_stat->rhl.comlenlen;
+  snmp_asn1_enc_raw(p, ofs, m_stat->rhl.comlen, m_stat->community);
+  ofs += m_stat->rhl.comlen;
+
+  snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_CONTXT | SNMP_ASN1_CONSTR | SNMP_ASN1_PDU_GET_RESP));
+  ofs += 1;
+  snmp_asn1_enc_length(p, ofs, m_stat->rhl.pdulen);
+  ofs += m_stat->rhl.pdulenlen;
+
+  snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG));
+  ofs += 1;
+  snmp_asn1_enc_length(p, ofs, m_stat->rhl.ridlen);
+  ofs += m_stat->rhl.ridlenlen;
+  snmp_asn1_enc_s32t(p, ofs, m_stat->rhl.ridlen, m_stat->rid);
+  ofs += m_stat->rhl.ridlen;
+
+  snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG));
+  ofs += 1;
+  snmp_asn1_enc_length(p, ofs, m_stat->rhl.errstatlen);
+  ofs += m_stat->rhl.errstatlenlen;
+  snmp_asn1_enc_s32t(p, ofs, m_stat->rhl.errstatlen, m_stat->error_status);
+  ofs += m_stat->rhl.errstatlen;
+
+  snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG));
+  ofs += 1;
+  snmp_asn1_enc_length(p, ofs, m_stat->rhl.erridxlen);
+  ofs += m_stat->rhl.erridxlenlen;
+  snmp_asn1_enc_s32t(p, ofs, m_stat->rhl.erridxlen, m_stat->error_index);
+  ofs += m_stat->rhl.erridxlen;
+
+  return ofs;
+}
+
+/**
+ * Encodes trap header from head to tail.
+ */
+static u16_t
+snmp_trap_header_enc(struct snmp_msg_trap *m_trap, struct pbuf *p)
+{
+  u16_t ofs;
+
+  ofs = 0;
+  snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_CONSTR | SNMP_ASN1_SEQ));
+  ofs += 1;
+  snmp_asn1_enc_length(p, ofs, m_trap->thl.seqlen);
+  ofs += m_trap->thl.seqlenlen;
+
+  snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG));
+  ofs += 1;
+  snmp_asn1_enc_length(p, ofs, m_trap->thl.verlen);
+  ofs += m_trap->thl.verlenlen;
+  snmp_asn1_enc_s32t(p, ofs, m_trap->thl.verlen, snmp_version);
+  ofs += m_trap->thl.verlen;
+
+  snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR));
+  ofs += 1;
+  snmp_asn1_enc_length(p, ofs, m_trap->thl.comlen);
+  ofs += m_trap->thl.comlenlen;
+  snmp_asn1_enc_raw(p, ofs, m_trap->thl.comlen, (u8_t *)&snmp_publiccommunity[0]);
+  ofs += m_trap->thl.comlen;
+
+  snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_CONTXT | SNMP_ASN1_CONSTR | SNMP_ASN1_PDU_TRAP));
+  ofs += 1;
+  snmp_asn1_enc_length(p, ofs, m_trap->thl.pdulen);
+  ofs += m_trap->thl.pdulenlen;
+
+  snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OBJ_ID));
+  ofs += 1;
+  snmp_asn1_enc_length(p, ofs, m_trap->thl.eidlen);
+  ofs += m_trap->thl.eidlenlen;
+  snmp_asn1_enc_oid(p, ofs, m_trap->enterprise->len, &m_trap->enterprise->id[0]);
+  ofs += m_trap->thl.eidlen;
+
+  snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_IPADDR));
+  ofs += 1;
+  snmp_asn1_enc_length(p, ofs, m_trap->thl.aaddrlen);
+  ofs += m_trap->thl.aaddrlenlen;
+  snmp_asn1_enc_raw(p, ofs, m_trap->thl.aaddrlen, &m_trap->sip_raw[0]);
+  ofs += m_trap->thl.aaddrlen;
+
+  snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG));
+  ofs += 1;
+  snmp_asn1_enc_length(p, ofs, m_trap->thl.gtrplen);
+  ofs += m_trap->thl.gtrplenlen;
+  snmp_asn1_enc_u32t(p, ofs, m_trap->thl.gtrplen, m_trap->gen_trap);
+  ofs += m_trap->thl.gtrplen;
+
+  snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG));
+  ofs += 1;
+  snmp_asn1_enc_length(p, ofs, m_trap->thl.strplen);
+  ofs += m_trap->thl.strplenlen;
+  snmp_asn1_enc_u32t(p, ofs, m_trap->thl.strplen, m_trap->spc_trap);
+  ofs += m_trap->thl.strplen;
+
+  snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_TIMETICKS));
+  ofs += 1;
+  snmp_asn1_enc_length(p, ofs, m_trap->thl.tslen);
+  ofs += m_trap->thl.tslenlen;
+  snmp_asn1_enc_u32t(p, ofs, m_trap->thl.tslen, m_trap->ts);
+  ofs += m_trap->thl.tslen;
+
+  return ofs;
+}
+
+/**
+ * Encodes varbind list from head to tail.
+ */
+static u16_t
+snmp_varbind_list_enc(struct snmp_varbind_root *root, struct pbuf *p, u16_t ofs)
+{
+  struct snmp_varbind *vb;
+  s32_t *sint_ptr;
+  u32_t *uint_ptr;
+  u8_t *raw_ptr;
+
+  snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_CONSTR | SNMP_ASN1_SEQ));
+  ofs += 1;
+  snmp_asn1_enc_length(p, ofs, root->seqlen);
+  ofs += root->seqlenlen;
+
+  vb = root->head;
+  while ( vb != NULL )
+  {
+    snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_CONSTR | SNMP_ASN1_SEQ));
+    ofs += 1;
+    snmp_asn1_enc_length(p, ofs, vb->seqlen);
+    ofs += vb->seqlenlen;
+
+    snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OBJ_ID));
+    ofs += 1;
+    snmp_asn1_enc_length(p, ofs, vb->olen);
+    ofs += vb->olenlen;
+    snmp_asn1_enc_oid(p, ofs, vb->ident_len, &vb->ident[0]);
+    ofs += vb->olen;
+
+    snmp_asn1_enc_type(p, ofs, vb->value_type);
+    ofs += 1;
+    snmp_asn1_enc_length(p, ofs, vb->vlen);
+    ofs += vb->vlenlen;
+
+    switch (vb->value_type)
+    {
+      case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG):
+        sint_ptr = (s32_t*)vb->value;
+        snmp_asn1_enc_s32t(p, ofs, vb->vlen, *sint_ptr);
+        break;
+      case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_COUNTER):
+      case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_GAUGE):
+      case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_TIMETICKS):
+        uint_ptr = (u32_t*)vb->value;
+        snmp_asn1_enc_u32t(p, ofs, vb->vlen, *uint_ptr);
+        break;
+      case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR):
+      case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_IPADDR):
+      case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_OPAQUE):
+        raw_ptr = (u8_t*)vb->value;
+        snmp_asn1_enc_raw(p, ofs, vb->vlen, raw_ptr);
+        break;
+      case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_NUL):
+        break;
+      case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OBJ_ID):
+        sint_ptr = (s32_t*)vb->value;
+        snmp_asn1_enc_oid(p, ofs, vb->value_len / sizeof(s32_t), sint_ptr);
+        break;
+      default:
+        /* unsupported type */
+        break;
+    };
+    ofs += vb->vlen;
+    vb = vb->next;
+  }
+  return ofs;
+}
+
+#endif /* LWIP_SNMP */
diff --git a/core/lwip/src/core/stats.c b/core/lwip/src/core/stats.c
new file mode 100644
index 00000000..69f97d41
--- /dev/null
+++ b/core/lwip/src/core/stats.c
@@ -0,0 +1,176 @@
+/**
+ * @file
+ * Statistics module
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_STATS /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/def.h"
+#include "lwip/stats.h"
+#include "lwip/mem.h"
+
+#include <string.h>
+
+struct stats_ lwip_stats;
+
+void stats_init(void)
+{
+#ifdef LWIP_DEBUG
+#if MEMP_STATS
+  const char * memp_names[] = {
+#define LWIP_MEMPOOL(name,num,size,desc) desc,
+#include "lwip/memp_std.h"
+  };
+  int i;
+  for (i = 0; i < MEMP_MAX; i++) {
+    lwip_stats.memp[i].name = memp_names[i];
+  }
+#endif /* MEMP_STATS */
+#if MEM_STATS
+  lwip_stats.mem.name = "MEM";
+#endif /* MEM_STATS */
+#endif /* LWIP_DEBUG */
+}
+
+#if LWIP_STATS_DISPLAY
+void
+stats_display_proto(struct stats_proto *proto, char *name)
+{
+  LWIP_PLATFORM_DIAG(("\n%s\n\t", name));
+  LWIP_PLATFORM_DIAG(("xmit: %"STAT_COUNTER_F"\n\t", proto->xmit)); 
+  LWIP_PLATFORM_DIAG(("recv: %"STAT_COUNTER_F"\n\t", proto->recv)); 
+  LWIP_PLATFORM_DIAG(("fw: %"STAT_COUNTER_F"\n\t", proto->fw)); 
+  LWIP_PLATFORM_DIAG(("drop: %"STAT_COUNTER_F"\n\t", proto->drop)); 
+  LWIP_PLATFORM_DIAG(("chkerr: %"STAT_COUNTER_F"\n\t", proto->chkerr)); 
+  LWIP_PLATFORM_DIAG(("lenerr: %"STAT_COUNTER_F"\n\t", proto->lenerr)); 
+  LWIP_PLATFORM_DIAG(("memerr: %"STAT_COUNTER_F"\n\t", proto->memerr)); 
+  LWIP_PLATFORM_DIAG(("rterr: %"STAT_COUNTER_F"\n\t", proto->rterr)); 
+  LWIP_PLATFORM_DIAG(("proterr: %"STAT_COUNTER_F"\n\t", proto->proterr)); 
+  LWIP_PLATFORM_DIAG(("opterr: %"STAT_COUNTER_F"\n\t", proto->opterr)); 
+  LWIP_PLATFORM_DIAG(("err: %"STAT_COUNTER_F"\n\t", proto->err)); 
+  LWIP_PLATFORM_DIAG(("cachehit: %"STAT_COUNTER_F"\n", proto->cachehit)); 
+}
+
+#if IGMP_STATS
+void
+stats_display_igmp(struct stats_igmp *igmp)
+{
+  LWIP_PLATFORM_DIAG(("\nIGMP\n\t"));
+  LWIP_PLATFORM_DIAG(("xmit: %"STAT_COUNTER_F"\n\t", igmp->xmit)); 
+  LWIP_PLATFORM_DIAG(("recv: %"STAT_COUNTER_F"\n\t", igmp->recv)); 
+  LWIP_PLATFORM_DIAG(("drop: %"STAT_COUNTER_F"\n\t", igmp->drop)); 
+  LWIP_PLATFORM_DIAG(("chkerr: %"STAT_COUNTER_F"\n\t", igmp->chkerr)); 
+  LWIP_PLATFORM_DIAG(("lenerr: %"STAT_COUNTER_F"\n\t", igmp->lenerr)); 
+  LWIP_PLATFORM_DIAG(("memerr: %"STAT_COUNTER_F"\n\t", igmp->memerr)); 
+  LWIP_PLATFORM_DIAG(("proterr: %"STAT_COUNTER_F"\n\t", igmp->proterr)); 
+  LWIP_PLATFORM_DIAG(("rx_v1: %"STAT_COUNTER_F"\n\t", igmp->rx_v1)); 
+  LWIP_PLATFORM_DIAG(("rx_group: %"STAT_COUNTER_F"\n", igmp->rx_group));
+  LWIP_PLATFORM_DIAG(("rx_general: %"STAT_COUNTER_F"\n", igmp->rx_general));
+  LWIP_PLATFORM_DIAG(("rx_report: %"STAT_COUNTER_F"\n\t", igmp->rx_report)); 
+  LWIP_PLATFORM_DIAG(("tx_join: %"STAT_COUNTER_F"\n\t", igmp->tx_join)); 
+  LWIP_PLATFORM_DIAG(("tx_leave: %"STAT_COUNTER_F"\n\t", igmp->tx_leave)); 
+  LWIP_PLATFORM_DIAG(("tx_report: %"STAT_COUNTER_F"\n\t", igmp->tx_report)); 
+}
+#endif /* IGMP_STATS */
+
+#if MEM_STATS || MEMP_STATS
+void
+stats_display_mem(struct stats_mem *mem, char *name)
+{
+  LWIP_PLATFORM_DIAG(("\nMEM %s\n\t", name));
+  LWIP_PLATFORM_DIAG(("avail: %"U32_F"\n\t", (u32_t)mem->avail)); 
+  LWIP_PLATFORM_DIAG(("used: %"U32_F"\n\t", (u32_t)mem->used)); 
+  LWIP_PLATFORM_DIAG(("max: %"U32_F"\n\t", (u32_t)mem->max)); 
+  LWIP_PLATFORM_DIAG(("err: %"U32_F"\n", (u32_t)mem->err));
+}
+
+#if MEMP_STATS
+void
+stats_display_memp(struct stats_mem *mem, int index)
+{
+  char * memp_names[] = {
+#define LWIP_MEMPOOL(name,num,size,desc) desc,
+#include "lwip/memp_std.h"
+  };
+  if(index < MEMP_MAX) {
+    stats_display_mem(mem, memp_names[index]);
+  }
+}
+#endif /* MEMP_STATS */
+#endif /* MEM_STATS || MEMP_STATS */
+
+#if SYS_STATS
+void
+stats_display_sys(struct stats_sys *sys)
+{
+  LWIP_PLATFORM_DIAG(("\nSYS\n\t"));
+  LWIP_PLATFORM_DIAG(("sem.used:  %"U32_F"\n\t", (u32_t)sys->sem.used)); 
+  LWIP_PLATFORM_DIAG(("sem.max:   %"U32_F"\n\t", (u32_t)sys->sem.max)); 
+  LWIP_PLATFORM_DIAG(("sem.err:   %"U32_F"\n\t", (u32_t)sys->sem.err)); 
+  LWIP_PLATFORM_DIAG(("mutex.used: %"U32_F"\n\t", (u32_t)sys->mutex.used)); 
+  LWIP_PLATFORM_DIAG(("mutex.max:  %"U32_F"\n\t", (u32_t)sys->mutex.max)); 
+  LWIP_PLATFORM_DIAG(("mutex.err:  %"U32_F"\n\t", (u32_t)sys->mutex.err)); 
+  LWIP_PLATFORM_DIAG(("mbox.used:  %"U32_F"\n\t", (u32_t)sys->mbox.used)); 
+  LWIP_PLATFORM_DIAG(("mbox.max:   %"U32_F"\n\t", (u32_t)sys->mbox.max)); 
+  LWIP_PLATFORM_DIAG(("mbox.err:   %"U32_F"\n\t", (u32_t)sys->mbox.err)); 
+}
+#endif /* SYS_STATS */
+
+void
+stats_display(void)
+{
+  s16_t i;
+
+  LINK_STATS_DISPLAY();
+  ETHARP_STATS_DISPLAY();
+  IPFRAG_STATS_DISPLAY();
+  IP_STATS_DISPLAY();
+  IGMP_STATS_DISPLAY();
+  ICMP_STATS_DISPLAY();
+  UDP_STATS_DISPLAY();
+  TCP_STATS_DISPLAY();
+  MEM_STATS_DISPLAY();
+  for (i = 0; i < MEMP_MAX; i++) {
+    MEMP_STATS_DISPLAY(i);
+  }
+  SYS_STATS_DISPLAY();
+}
+#endif /* LWIP_STATS_DISPLAY */
+
+#endif /* LWIP_STATS */
+
diff --git a/core/lwip/src/core/sys.c b/core/lwip/src/core/sys.c
new file mode 100644
index 00000000..d3a77deb
--- /dev/null
+++ b/core/lwip/src/core/sys.c
@@ -0,0 +1,66 @@
+/**
+ * @file
+ * lwIP Operating System abstraction
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#include "lwip/sys.h"
+
+/* Most of the functions defined in sys.h must be implemented in the
+ * architecture-dependent file sys_arch.c */
+
+#if !NO_SYS
+
+/**
+ * Sleep for some ms. Timeouts are NOT processed while sleeping.
+ *
+ * @param ms number of milliseconds to sleep
+ */
+void
+sys_msleep(u32_t ms)
+{
+  if (ms > 0) {
+    sys_sem_t delaysem;
+    err_t err = sys_sem_new(&delaysem, 0);
+    if (err == ERR_OK) {
+      sys_arch_sem_wait(&delaysem, ms);
+      sys_sem_free(&delaysem);
+    }
+  }
+}
+
+#endif /* !NO_SYS */
diff --git a/core/lwip/src/core/tcp.c b/core/lwip/src/core/tcp.c
new file mode 100644
index 00000000..c629bc4e
--- /dev/null
+++ b/core/lwip/src/core/tcp.c
@@ -0,0 +1,1635 @@
+/**
+ * @file
+ * Transmission Control Protocol for IP
+ *
+ * This file contains common functions for the TCP implementation, such as functinos
+ * for manipulating the data structures and the TCP timer functions. TCP functions
+ * related to input and output is found in tcp_in.c and tcp_out.c respectively.
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/def.h"
+#include "lwip/mem.h"
+#include "lwip/memp.h"
+#include "lwip/snmp.h"
+#include "lwip/tcp.h"
+#include "lwip/tcp_impl.h"
+#include "lwip/debug.h"
+#include "lwip/stats.h"
+
+#include <string.h>
+
+const char * const tcp_state_str[] = {
+  "CLOSED",      
+  "LISTEN",      
+  "SYN_SENT",    
+  "SYN_RCVD",    
+  "ESTABLISHED", 
+  "FIN_WAIT_1",  
+  "FIN_WAIT_2",  
+  "CLOSE_WAIT",  
+  "CLOSING",     
+  "LAST_ACK",    
+  "TIME_WAIT"   
+};
+
+/* Incremented every coarse grained timer shot (typically every 500 ms). */
+u32_t tcp_ticks;
+const u8_t tcp_backoff[13] =
+    { 1, 2, 3, 4, 5, 6, 7, 7, 7, 7, 7, 7, 7};
+ /* Times per slowtmr hits */
+const u8_t tcp_persist_backoff[7] = { 3, 6, 12, 24, 48, 96, 120 };
+
+/* The TCP PCB lists. */
+
+/** List of all TCP PCBs bound but not yet (connected || listening) */
+struct tcp_pcb *tcp_bound_pcbs;
+/** List of all TCP PCBs in LISTEN state */
+union tcp_listen_pcbs_t tcp_listen_pcbs;
+/** List of all TCP PCBs that are in a state in which
+ * they accept or send data. */
+struct tcp_pcb *tcp_active_pcbs;
+/** List of all TCP PCBs in TIME-WAIT state */
+struct tcp_pcb *tcp_tw_pcbs;
+
+#define NUM_TCP_PCB_LISTS               4
+#define NUM_TCP_PCB_LISTS_NO_TIME_WAIT  3
+/** An array with all (non-temporary) PCB lists, mainly used for smaller code size */
+struct tcp_pcb ** const tcp_pcb_lists[] = {&tcp_listen_pcbs.pcbs, &tcp_bound_pcbs,
+  &tcp_active_pcbs, &tcp_tw_pcbs};
+
+/** Only used for temporary storage. */
+struct tcp_pcb *tcp_tmp_pcb;
+
+/** Timer counter to handle calling slow-timer from tcp_tmr() */ 
+static u8_t tcp_timer;
+static u16_t tcp_new_port(void);
+
+/**
+ * Called periodically to dispatch TCP timers.
+ *
+ */
+void
+tcp_tmr(void)
+{
+  /* Call tcp_fasttmr() every 250 ms */
+  tcp_fasttmr();
+
+  if (++tcp_timer & 1) {
+    /* Call tcp_tmr() every 500 ms, i.e., every other timer
+       tcp_tmr() is called. */
+    tcp_slowtmr();
+  }
+}
+
+/**
+ * Closes the TX side of a connection held by the PCB.
+ * For tcp_close(), a RST is sent if the application didn't receive all data
+ * (tcp_recved() not called for all data passed to recv callback).
+ *
+ * Listening pcbs are freed and may not be referenced any more.
+ * Connection pcbs are freed if not yet connected and may not be referenced
+ * any more. If a connection is established (at least SYN received or in
+ * a closing state), the connection is closed, and put in a closing state.
+ * The pcb is then automatically freed in tcp_slowtmr(). It is therefore
+ * unsafe to reference it.
+ *
+ * @param pcb the tcp_pcb to close
+ * @return ERR_OK if connection has been closed
+ *         another err_t if closing failed and pcb is not freed
+ */
+static err_t
+tcp_close_shutdown(struct tcp_pcb *pcb, u8_t rst_on_unacked_data)
+{
+  err_t err;
+
+  if (rst_on_unacked_data && (pcb->state != LISTEN)) {
+    if ((pcb->refused_data != NULL) || (pcb->rcv_wnd != TCP_WND)) {
+      /* Not all data received by application, send RST to tell the remote
+         side about this. */
+      LWIP_ASSERT("pcb->flags & TF_RXCLOSED", pcb->flags & TF_RXCLOSED);
+
+      /* don't call tcp_abort here: we must not deallocate the pcb since
+         that might not be expected when calling tcp_close */
+      tcp_rst(pcb->snd_nxt, pcb->rcv_nxt, &pcb->local_ip, &pcb->remote_ip,
+        pcb->local_port, pcb->remote_port);
+
+      tcp_pcb_purge(pcb);
+
+      /* TODO: to which state do we move now? */
+
+      /* move to TIME_WAIT since we close actively */
+      TCP_RMV(&tcp_active_pcbs, pcb);
+      pcb->state = TIME_WAIT;
+      TCP_REG(&tcp_tw_pcbs, pcb);
+
+      return ERR_OK;
+    }
+  }
+
+  switch (pcb->state) {
+  case CLOSED:
+    /* Closing a pcb in the CLOSED state might seem erroneous,
+     * however, it is in this state once allocated and as yet unused
+     * and the user needs some way to free it should the need arise.
+     * Calling tcp_close() with a pcb that has already been closed, (i.e. twice)
+     * or for a pcb that has been used and then entered the CLOSED state 
+     * is erroneous, but this should never happen as the pcb has in those cases
+     * been freed, and so any remaining handles are bogus. */
+    err = ERR_OK;
+    if (pcb->local_port != 0) {
+      TCP_RMV(&tcp_bound_pcbs, pcb);
+    }
+    memp_free(MEMP_TCP_PCB, pcb);
+    pcb = NULL;
+    break;
+  case LISTEN:
+    err = ERR_OK;
+    tcp_pcb_remove(&tcp_listen_pcbs.pcbs, pcb);
+    memp_free(MEMP_TCP_PCB_LISTEN, pcb);
+    pcb = NULL;
+    break;
+  case SYN_SENT:
+    err = ERR_OK;
+    tcp_pcb_remove(&tcp_active_pcbs, pcb);
+    memp_free(MEMP_TCP_PCB, pcb);
+    pcb = NULL;
+    snmp_inc_tcpattemptfails();
+    break;
+  case SYN_RCVD:
+    err = tcp_send_fin(pcb);
+    if (err == ERR_OK) {
+      snmp_inc_tcpattemptfails();
+      pcb->state = FIN_WAIT_1;
+    }
+    break;
+  case ESTABLISHED:
+    err = tcp_send_fin(pcb);
+    if (err == ERR_OK) {
+      snmp_inc_tcpestabresets();
+      pcb->state = FIN_WAIT_1;
+    }
+    break;
+  case CLOSE_WAIT:
+    err = tcp_send_fin(pcb);
+    if (err == ERR_OK) {
+      snmp_inc_tcpestabresets();
+      pcb->state = LAST_ACK;
+    }
+    break;
+  default:
+    /* Has already been closed, do nothing. */
+    err = ERR_OK;
+    pcb = NULL;
+    break;
+  }
+
+  if (pcb != NULL && err == ERR_OK) {
+    /* To ensure all data has been sent when tcp_close returns, we have
+       to make sure tcp_output doesn't fail.
+       Since we don't really have to ensure all data has been sent when tcp_close
+       returns (unsent data is sent from tcp timer functions, also), we don't care
+       for the return value of tcp_output for now. */
+    /* @todo: When implementing SO_LINGER, this must be changed somehow:
+       If SOF_LINGER is set, the data should be sent and acked before close returns.
+       This can only be valid for sequential APIs, not for the raw API. */
+    tcp_output(pcb);
+  }
+  return err;
+}
+
+/**
+ * Closes the connection held by the PCB.
+ *
+ * Listening pcbs are freed and may not be referenced any more.
+ * Connection pcbs are freed if not yet connected and may not be referenced
+ * any more. If a connection is established (at least SYN received or in
+ * a closing state), the connection is closed, and put in a closing state.
+ * The pcb is then automatically freed in tcp_slowtmr(). It is therefore
+ * unsafe to reference it (unless an error is returned).
+ *
+ * @param pcb the tcp_pcb to close
+ * @return ERR_OK if connection has been closed
+ *         another err_t if closing failed and pcb is not freed
+ */
+err_t
+tcp_close(struct tcp_pcb *pcb)
+{
+#if TCP_DEBUG
+  LWIP_DEBUGF(TCP_DEBUG, ("tcp_close: closing in "));
+  tcp_debug_print_state(pcb->state);
+#endif /* TCP_DEBUG */
+
+  if (pcb->state != LISTEN) {
+    /* Set a flag not to receive any more data... */
+    pcb->flags |= TF_RXCLOSED;
+  }
+  /* ... and close */
+  return tcp_close_shutdown(pcb, 1);
+}
+
+/**
+ * Causes all or part of a full-duplex connection of this PCB to be shut down.
+ * This doesn't deallocate the PCB!
+ *
+ * @param pcb PCB to shutdown
+ * @param shut_rx shut down receive side if this is != 0
+ * @param shut_tx shut down send side if this is != 0
+ * @return ERR_OK if shutdown succeeded (or the PCB has already been shut down)
+ *         another err_t on error.
+ */
+err_t
+tcp_shutdown(struct tcp_pcb *pcb, int shut_rx, int shut_tx)
+{
+  if (pcb->state == LISTEN) {
+    return ERR_CONN;
+  }
+  if (shut_rx) {
+    /* shut down the receive side: free buffered data... */
+    if (pcb->refused_data != NULL) {
+      pbuf_free(pcb->refused_data);
+      pcb->refused_data = NULL;
+    }
+    /* ... and set a flag not to receive any more data */
+    pcb->flags |= TF_RXCLOSED;
+  }
+  if (shut_tx) {
+    /* This can't happen twice since if it succeeds, the pcb's state is changed.
+       Only close in these states as the others directly deallocate the PCB */
+    switch (pcb->state) {
+  case SYN_RCVD:
+  case ESTABLISHED:
+  case CLOSE_WAIT:
+    return tcp_close_shutdown(pcb, 0);
+  default:
+    /* don't shut down other states */
+    break;
+    }
+  }
+  /* @todo: return another err_t if not in correct state or already shut? */
+  return ERR_OK;
+}
+
+/**
+ * Abandons a connection and optionally sends a RST to the remote
+ * host.  Deletes the local protocol control block. This is done when
+ * a connection is killed because of shortage of memory.
+ *
+ * @param pcb the tcp_pcb to abort
+ * @param reset boolean to indicate whether a reset should be sent
+ */
+void
+tcp_abandon(struct tcp_pcb *pcb, int reset)
+{
+  u32_t seqno, ackno;
+  u16_t remote_port, local_port;
+  ip_addr_t remote_ip, local_ip;
+#if LWIP_CALLBACK_API  
+  tcp_err_fn errf;
+#endif /* LWIP_CALLBACK_API */
+  void *errf_arg;
+
+  /* pcb->state LISTEN not allowed here */
+  LWIP_ASSERT("don't call tcp_abort/tcp_abandon for listen-pcbs",
+    pcb->state != LISTEN);
+  /* Figure out on which TCP PCB list we are, and remove us. If we
+     are in an active state, call the receive function associated with
+     the PCB with a NULL argument, and send an RST to the remote end. */
+  if (pcb->state == TIME_WAIT) {
+    tcp_pcb_remove(&tcp_tw_pcbs, pcb);
+    memp_free(MEMP_TCP_PCB, pcb);
+  } else {
+    seqno = pcb->snd_nxt;
+    ackno = pcb->rcv_nxt;
+    ip_addr_copy(local_ip, pcb->local_ip);
+    ip_addr_copy(remote_ip, pcb->remote_ip);
+    local_port = pcb->local_port;
+    remote_port = pcb->remote_port;
+#if LWIP_CALLBACK_API
+    errf = pcb->errf;
+#endif /* LWIP_CALLBACK_API */
+    errf_arg = pcb->callback_arg;
+    tcp_pcb_remove(&tcp_active_pcbs, pcb);
+    if (pcb->unacked != NULL) {
+      tcp_segs_free(pcb->unacked);
+    }
+    if (pcb->unsent != NULL) {
+      tcp_segs_free(pcb->unsent);
+    }
+#if TCP_QUEUE_OOSEQ    
+    if (pcb->ooseq != NULL) {
+      tcp_segs_free(pcb->ooseq);
+    }
+#endif /* TCP_QUEUE_OOSEQ */
+    memp_free(MEMP_TCP_PCB, pcb);
+    TCP_EVENT_ERR(errf, errf_arg, ERR_ABRT);
+    if (reset) {
+      LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_abandon: sending RST\n"));
+      tcp_rst(seqno, ackno, &local_ip, &remote_ip, local_port, remote_port);
+    }
+  }
+}
+
+/**
+ * Aborts the connection by sending a RST (reset) segment to the remote
+ * host. The pcb is deallocated. This function never fails.
+ *
+ * ATTENTION: When calling this from one of the TCP callbacks, make
+ * sure you always return ERR_ABRT (and never return ERR_ABRT otherwise
+ * or you will risk accessing deallocated memory or memory leaks!
+ *
+ * @param pcb the tcp pcb to abort
+ */
+void
+tcp_abort(struct tcp_pcb *pcb)
+{
+  tcp_abandon(pcb, 1);
+}
+
+/**
+ * Binds the connection to a local portnumber and IP address. If the
+ * IP address is not given (i.e., ipaddr == NULL), the IP address of
+ * the outgoing network interface is used instead.
+ *
+ * @param pcb the tcp_pcb to bind (no check is done whether this pcb is
+ *        already bound!)
+ * @param ipaddr the local ip address to bind to (use IP_ADDR_ANY to bind
+ *        to any local address
+ * @param port the local port to bind to
+ * @return ERR_USE if the port is already in use
+ *         ERR_VAL if bind failed because the PCB is not in a valid state
+ *         ERR_OK if bound
+ */
+err_t
+tcp_bind(struct tcp_pcb *pcb, ip_addr_t *ipaddr, u16_t port)
+{
+  int i;
+  int max_pcb_list = NUM_TCP_PCB_LISTS;
+  struct tcp_pcb *cpcb;
+
+  LWIP_ERROR("tcp_bind: can only bind in state CLOSED", pcb->state == CLOSED, return ERR_VAL);
+
+#if SO_REUSE
+  /* Unless the REUSEADDR flag is set,
+     we have to check the pcbs in TIME-WAIT state, also.
+     We do not dump TIME_WAIT pcb's; they can still be matched by incoming
+     packets using both local and remote IP addresses and ports to distinguish.
+   */
+  if ((pcb->so_options & SOF_REUSEADDR) != 0) {
+    max_pcb_list = NUM_TCP_PCB_LISTS_NO_TIME_WAIT;
+  }
+#endif /* SO_REUSE */
+
+  if (port == 0) {
+    port = tcp_new_port();
+  }
+
+  /* Check if the address already is in use (on all lists) */
+  for (i = 0; i < max_pcb_list; i++) {
+    for(cpcb = *tcp_pcb_lists[i]; cpcb != NULL; cpcb = cpcb->next) {
+      if (cpcb->local_port == port) {
+#if SO_REUSE
+        /* Omit checking for the same port if both pcbs have REUSEADDR set.
+           For SO_REUSEADDR, the duplicate-check for a 5-tuple is done in
+           tcp_connect. */
+        if (((pcb->so_options & SOF_REUSEADDR) == 0) ||
+          ((cpcb->so_options & SOF_REUSEADDR) == 0))
+#endif /* SO_REUSE */
+        {
+          if (ip_addr_isany(&(cpcb->local_ip)) ||
+              ip_addr_isany(ipaddr) ||
+              ip_addr_cmp(&(cpcb->local_ip), ipaddr)) {
+            return ERR_USE;
+          }
+        }
+      }
+    }
+  }
+
+  if (!ip_addr_isany(ipaddr)) {
+    pcb->local_ip = *ipaddr;
+  }
+  pcb->local_port = port;
+  TCP_REG(&tcp_bound_pcbs, pcb);
+  LWIP_DEBUGF(TCP_DEBUG, ("tcp_bind: bind to port %"U16_F"\n", port));
+  return ERR_OK;
+}
+#if LWIP_CALLBACK_API
+/**
+ * Default accept callback if no accept callback is specified by the user.
+ */
+static err_t
+tcp_accept_null(void *arg, struct tcp_pcb *pcb, err_t err)
+{
+  LWIP_UNUSED_ARG(arg);
+  LWIP_UNUSED_ARG(pcb);
+  LWIP_UNUSED_ARG(err);
+
+  return ERR_ABRT;
+}
+#endif /* LWIP_CALLBACK_API */
+
+/**
+ * Set the state of the connection to be LISTEN, which means that it
+ * is able to accept incoming connections. The protocol control block
+ * is reallocated in order to consume less memory. Setting the
+ * connection to LISTEN is an irreversible process.
+ *
+ * @param pcb the original tcp_pcb
+ * @param backlog the incoming connections queue limit
+ * @return tcp_pcb used for listening, consumes less memory.
+ *
+ * @note The original tcp_pcb is freed. This function therefore has to be
+ *       called like this:
+ *             tpcb = tcp_listen(tpcb);
+ */
+struct tcp_pcb *
+tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog)
+{
+  struct tcp_pcb_listen *lpcb;
+
+  LWIP_UNUSED_ARG(backlog);
+  LWIP_ERROR("tcp_listen: pcb already connected", pcb->state == CLOSED, return NULL);
+
+  /* already listening? */
+  if (pcb->state == LISTEN) {
+    return pcb;
+  }
+#if SO_REUSE
+  if ((pcb->so_options & SOF_REUSEADDR) != 0) {
+    /* Since SOF_REUSEADDR allows reusing a local address before the pcb's usage
+       is declared (listen-/connection-pcb), we have to make sure now that
+       this port is only used once for every local IP. */
+    for(lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
+      if (lpcb->local_port == pcb->local_port) {
+        if (ip_addr_cmp(&lpcb->local_ip, &pcb->local_ip)) {
+          /* this address/port is already used */
+          return NULL;
+        }
+      }
+    }
+  }
+#endif /* SO_REUSE */
+  lpcb = (struct tcp_pcb_listen *)memp_malloc(MEMP_TCP_PCB_LISTEN);
+  if (lpcb == NULL) {
+    return NULL;
+  }
+  lpcb->callback_arg = pcb->callback_arg;
+  lpcb->local_port = pcb->local_port;
+  lpcb->state = LISTEN;
+  lpcb->prio = pcb->prio;
+  lpcb->so_options = pcb->so_options;
+  lpcb->so_options |= SOF_ACCEPTCONN;
+  lpcb->ttl = pcb->ttl;
+  lpcb->tos = pcb->tos;
+  ip_addr_copy(lpcb->local_ip, pcb->local_ip);
+  if (pcb->local_port != 0) {
+    TCP_RMV(&tcp_bound_pcbs, pcb);
+  }
+  memp_free(MEMP_TCP_PCB, pcb);
+#if LWIP_CALLBACK_API
+  lpcb->accept = tcp_accept_null;
+#endif /* LWIP_CALLBACK_API */
+#if TCP_LISTEN_BACKLOG
+  lpcb->accepts_pending = 0;
+  lpcb->backlog = (backlog ? backlog : 1);
+#endif /* TCP_LISTEN_BACKLOG */
+  TCP_REG(&tcp_listen_pcbs.pcbs, (struct tcp_pcb *)lpcb);
+  return (struct tcp_pcb *)lpcb;
+}
+
+/** 
+ * Update the state that tracks the available window space to advertise.
+ *
+ * Returns how much extra window would be advertised if we sent an
+ * update now.
+ */
+u32_t tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb)
+{
+  u32_t new_right_edge = pcb->rcv_nxt + pcb->rcv_wnd;
+
+  if (TCP_SEQ_GEQ(new_right_edge, pcb->rcv_ann_right_edge + LWIP_MIN((TCP_WND / 2), pcb->mss))) {
+    /* we can advertise more window */
+    pcb->rcv_ann_wnd = pcb->rcv_wnd;
+    return new_right_edge - pcb->rcv_ann_right_edge;
+  } else {
+    if (TCP_SEQ_GT(pcb->rcv_nxt, pcb->rcv_ann_right_edge)) {
+      /* Can happen due to other end sending out of advertised window,
+       * but within actual available (but not yet advertised) window */
+      pcb->rcv_ann_wnd = 0;
+    } else {
+      /* keep the right edge of window constant */
+      u32_t new_rcv_ann_wnd = pcb->rcv_ann_right_edge - pcb->rcv_nxt;
+      LWIP_ASSERT("new_rcv_ann_wnd <= 0xffff", new_rcv_ann_wnd <= 0xffff);
+      pcb->rcv_ann_wnd = (u16_t)new_rcv_ann_wnd;
+    }
+    return 0;
+  }
+}
+
+/**
+ * This function should be called by the application when it has
+ * processed the data. The purpose is to advertise a larger window
+ * when the data has been processed.
+ *
+ * @param pcb the tcp_pcb for which data is read
+ * @param len the amount of bytes that have been read by the application
+ */
+void
+tcp_recved(struct tcp_pcb *pcb, u16_t len)
+{
+  int wnd_inflation;
+
+  LWIP_ASSERT("tcp_recved: len would wrap rcv_wnd\n",
+              len <= 0xffff - pcb->rcv_wnd );
+
+  pcb->rcv_wnd += len;
+  if (pcb->rcv_wnd > TCP_WND) {
+    pcb->rcv_wnd = TCP_WND;
+  }
+
+  wnd_inflation = tcp_update_rcv_ann_wnd(pcb);
+
+  /* If the change in the right edge of window is significant (default
+   * watermark is TCP_WND/4), then send an explicit update now.
+   * Otherwise wait for a packet to be sent in the normal course of
+   * events (or more window to be available later) */
+  if (wnd_inflation >= TCP_WND_UPDATE_THRESHOLD) {
+    tcp_ack_now(pcb);
+    tcp_output(pcb);
+  }
+
+  LWIP_DEBUGF(TCP_DEBUG, ("tcp_recved: recveived %"U16_F" bytes, wnd %"U16_F" (%"U16_F").\n",
+         len, pcb->rcv_wnd, TCP_WND - pcb->rcv_wnd));
+}
+
+/**
+ * A nastly hack featuring 'goto' statements that allocates a
+ * new TCP local port.
+ *
+ * @return a new (free) local TCP port number
+ */
+static u16_t
+tcp_new_port(void)
+{
+  int i;
+  struct tcp_pcb *pcb;
+#ifndef TCP_LOCAL_PORT_RANGE_START
+/* From http://www.iana.org/assignments/port-numbers:
+   "The Dynamic and/or Private Ports are those from 49152 through 65535" */
+#define TCP_LOCAL_PORT_RANGE_START  0xc000
+#define TCP_LOCAL_PORT_RANGE_END    0xffff
+#endif
+  static u16_t port = TCP_LOCAL_PORT_RANGE_START;
+  
+ again:
+  if (port++ >= TCP_LOCAL_PORT_RANGE_END) {
+    port = TCP_LOCAL_PORT_RANGE_START;
+  }
+  /* Check all PCB lists. */
+  for (i = 0; i < NUM_TCP_PCB_LISTS; i++) {
+    for(pcb = *tcp_pcb_lists[i]; pcb != NULL; pcb = pcb->next) {
+      if (pcb->local_port == port) {
+        goto again;
+      }
+    }
+  }
+  return port;
+}
+
+/**
+ * Connects to another host. The function given as the "connected"
+ * argument will be called when the connection has been established.
+ *
+ * @param pcb the tcp_pcb used to establish the connection
+ * @param ipaddr the remote ip address to connect to
+ * @param port the remote tcp port to connect to
+ * @param connected callback function to call when connected (or on error)
+ * @return ERR_VAL if invalid arguments are given
+ *         ERR_OK if connect request has been sent
+ *         other err_t values if connect request couldn't be sent
+ */
+err_t
+tcp_connect(struct tcp_pcb *pcb, ip_addr_t *ipaddr, u16_t port,
+      tcp_connected_fn connected)
+{
+  err_t ret;
+  u32_t iss;
+  u16_t old_local_port;
+
+  LWIP_ERROR("tcp_connect: can only connect from state CLOSED", pcb->state == CLOSED, return ERR_ISCONN);
+
+  LWIP_DEBUGF(TCP_DEBUG, ("tcp_connect to port %"U16_F"\n", port));
+  if (ipaddr != NULL) {
+    pcb->remote_ip = *ipaddr;
+  } else {
+    return ERR_VAL;
+  }
+  pcb->remote_port = port;
+
+  /* check if we have a route to the remote host */
+  if (ip_addr_isany(&(pcb->local_ip))) {
+    /* no local IP address set, yet. */
+    struct netif *netif = ip_route(&(pcb->remote_ip));
+    if (netif == NULL) {
+      /* Don't even try to send a SYN packet if we have no route
+         since that will fail. */
+      return ERR_RTE;
+    }
+    /* Use the netif's IP address as local address. */
+    ip_addr_copy(pcb->local_ip, netif->ip_addr);
+  }
+
+  old_local_port = pcb->local_port;
+  if (pcb->local_port == 0) {
+    pcb->local_port = tcp_new_port();
+  }
+#if SO_REUSE
+  if ((pcb->so_options & SOF_REUSEADDR) != 0) {
+    /* Since SOF_REUSEADDR allows reusing a local address, we have to make sure
+       now that the 5-tuple is unique. */
+    struct tcp_pcb *cpcb;
+    int i;
+    /* Don't check listen- and bound-PCBs, check active- and TIME-WAIT PCBs. */
+    for (i = 2; i < NUM_TCP_PCB_LISTS; i++) {
+      for(cpcb = *tcp_pcb_lists[i]; cpcb != NULL; cpcb = cpcb->next) {
+        if ((cpcb->local_port == pcb->local_port) &&
+            (cpcb->remote_port == port) &&
+            ip_addr_cmp(&cpcb->local_ip, &pcb->local_ip) &&
+            ip_addr_cmp(&cpcb->remote_ip, ipaddr)) {
+          /* linux returns EISCONN here, but ERR_USE should be OK for us */
+          return ERR_USE;
+        }
+      }
+    }
+  }
+#endif /* SO_REUSE */
+  iss = tcp_next_iss();
+  pcb->rcv_nxt = 0;
+  pcb->snd_nxt = iss;
+  pcb->lastack = iss - 1;
+  pcb->snd_lbb = iss - 1;
+  pcb->rcv_wnd = TCP_WND;
+  pcb->rcv_ann_wnd = TCP_WND;
+  pcb->rcv_ann_right_edge = pcb->rcv_nxt;
+  pcb->snd_wnd = TCP_WND;
+  /* As initial send MSS, we use TCP_MSS but limit it to 536.
+     The send MSS is updated when an MSS option is received. */
+  pcb->mss = (TCP_MSS > 536) ? 536 : TCP_MSS;
+#if TCP_CALCULATE_EFF_SEND_MSS
+  pcb->mss = tcp_eff_send_mss(pcb->mss, ipaddr);
+#endif /* TCP_CALCULATE_EFF_SEND_MSS */
+  pcb->cwnd = 1;
+  pcb->ssthresh = pcb->mss * 10;
+#if LWIP_CALLBACK_API
+  pcb->connected = connected;
+#else /* LWIP_CALLBACK_API */  
+  LWIP_UNUSED_ARG(connected);
+#endif /* LWIP_CALLBACK_API */
+
+  /* Send a SYN together with the MSS option. */
+  ret = tcp_enqueue_flags(pcb, TCP_SYN);
+  if (ret == ERR_OK) {
+    /* SYN segment was enqueued, changed the pcbs state now */
+    pcb->state = SYN_SENT;
+    if (old_local_port != 0) {
+      TCP_RMV(&tcp_bound_pcbs, pcb);
+    }
+    TCP_REG(&tcp_active_pcbs, pcb);
+    snmp_inc_tcpactiveopens();
+
+    tcp_output(pcb);
+  }
+  return ret;
+}
+
+/**
+ * Called every 500 ms and implements the retransmission timer and the timer that
+ * removes PCBs that have been in TIME-WAIT for enough time. It also increments
+ * various timers such as the inactivity timer in each PCB.
+ *
+ * Automatically called from tcp_tmr().
+ */
+void
+tcp_slowtmr(void)
+{
+  struct tcp_pcb *pcb, *prev;
+  u16_t eff_wnd;
+  u8_t pcb_remove;      /* flag if a PCB should be removed */
+  u8_t pcb_reset;       /* flag if a RST should be sent when removing */
+  err_t err;
+
+  err = ERR_OK;
+
+  ++tcp_ticks;
+
+  /* Steps through all of the active PCBs. */
+  prev = NULL;
+  pcb = tcp_active_pcbs;
+  if (pcb == NULL) {
+    LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: no active pcbs\n"));
+  }
+  while (pcb != NULL) {
+    LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: processing active pcb\n"));
+    LWIP_ASSERT("tcp_slowtmr: active pcb->state != CLOSED\n", pcb->state != CLOSED);
+    LWIP_ASSERT("tcp_slowtmr: active pcb->state != LISTEN\n", pcb->state != LISTEN);
+    LWIP_ASSERT("tcp_slowtmr: active pcb->state != TIME-WAIT\n", pcb->state != TIME_WAIT);
+
+    pcb_remove = 0;
+    pcb_reset = 0;
+
+    if (pcb->state == SYN_SENT && pcb->nrtx == TCP_SYNMAXRTX) {
+      ++pcb_remove;
+      LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: max SYN retries reached\n"));
+    }
+    else if (pcb->nrtx == TCP_MAXRTX) {
+      ++pcb_remove;
+      LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: max DATA retries reached\n"));
+    } else {
+      if (pcb->persist_backoff > 0) {
+        /* If snd_wnd is zero, use persist timer to send 1 byte probes
+         * instead of using the standard retransmission mechanism. */
+        pcb->persist_cnt++;
+        if (pcb->persist_cnt >= tcp_persist_backoff[pcb->persist_backoff-1]) {
+          pcb->persist_cnt = 0;
+          if (pcb->persist_backoff < sizeof(tcp_persist_backoff)) {
+            pcb->persist_backoff++;
+          }
+          tcp_zero_window_probe(pcb);
+        }
+      } else {
+        /* Increase the retransmission timer if it is running */
+        if(pcb->rtime >= 0)
+          ++pcb->rtime;
+
+        if (pcb->unacked != NULL && pcb->rtime >= pcb->rto) {
+          /* Time for a retransmission. */
+          LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_slowtmr: rtime %"S16_F
+                                      " pcb->rto %"S16_F"\n",
+                                      pcb->rtime, pcb->rto));
+
+          /* Double retransmission time-out unless we are trying to
+           * connect to somebody (i.e., we are in SYN_SENT). */
+          if (pcb->state != SYN_SENT) {
+            pcb->rto = ((pcb->sa >> 3) + pcb->sv) << tcp_backoff[pcb->nrtx];
+          }
+
+          /* Reset the retransmission timer. */
+          pcb->rtime = 0;
+
+          /* Reduce congestion window and ssthresh. */
+          eff_wnd = LWIP_MIN(pcb->cwnd, pcb->snd_wnd);
+          pcb->ssthresh = eff_wnd >> 1;
+          if (pcb->ssthresh < (pcb->mss << 1)) {
+            pcb->ssthresh = (pcb->mss << 1);
+          }
+          pcb->cwnd = pcb->mss;
+          LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_slowtmr: cwnd %"U16_F
+                                       " ssthresh %"U16_F"\n",
+                                       pcb->cwnd, pcb->ssthresh));
+ 
+          /* The following needs to be called AFTER cwnd is set to one
+             mss - STJ */
+          tcp_rexmit_rto(pcb);
+        }
+      }
+    }
+    /* Check if this PCB has stayed too long in FIN-WAIT-2 */
+    if (pcb->state == FIN_WAIT_2) {
+      if ((u32_t)(tcp_ticks - pcb->tmr) >
+          TCP_FIN_WAIT_TIMEOUT / TCP_SLOW_INTERVAL) {
+        ++pcb_remove;
+        LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in FIN-WAIT-2\n"));
+      }
+    }
+
+    /* Check if KEEPALIVE should be sent */
+    if((pcb->so_options & SOF_KEEPALIVE) &&
+       ((pcb->state == ESTABLISHED) ||
+        (pcb->state == CLOSE_WAIT))) {
+#if LWIP_TCP_KEEPALIVE
+      if((u32_t)(tcp_ticks - pcb->tmr) >
+         (pcb->keep_idle + (pcb->keep_cnt*pcb->keep_intvl))
+         / TCP_SLOW_INTERVAL)
+#else      
+      if((u32_t)(tcp_ticks - pcb->tmr) >
+         (pcb->keep_idle + TCP_MAXIDLE) / TCP_SLOW_INTERVAL)
+#endif /* LWIP_TCP_KEEPALIVE */
+      {
+        LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: KEEPALIVE timeout. Aborting connection to %"U16_F".%"U16_F".%"U16_F".%"U16_F".\n",
+                                ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip),
+                                ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip)));
+        
+        ++pcb_remove;
+        ++pcb_reset;
+      }
+#if LWIP_TCP_KEEPALIVE
+      else if((u32_t)(tcp_ticks - pcb->tmr) > 
+              (pcb->keep_idle + pcb->keep_cnt_sent * pcb->keep_intvl)
+              / TCP_SLOW_INTERVAL)
+#else
+      else if((u32_t)(tcp_ticks - pcb->tmr) > 
+              (pcb->keep_idle + pcb->keep_cnt_sent * TCP_KEEPINTVL_DEFAULT) 
+              / TCP_SLOW_INTERVAL)
+#endif /* LWIP_TCP_KEEPALIVE */
+      {
+        tcp_keepalive(pcb);
+        pcb->keep_cnt_sent++;
+      }
+    }
+
+    /* If this PCB has queued out of sequence data, but has been
+       inactive for too long, will drop the data (it will eventually
+       be retransmitted). */
+#if TCP_QUEUE_OOSEQ
+    if (pcb->ooseq != NULL &&
+        (u32_t)tcp_ticks - pcb->tmr >= pcb->rto * TCP_OOSEQ_TIMEOUT) {
+      tcp_segs_free(pcb->ooseq);
+      pcb->ooseq = NULL;
+      LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_slowtmr: dropping OOSEQ queued data\n"));
+    }
+#endif /* TCP_QUEUE_OOSEQ */
+
+    /* Check if this PCB has stayed too long in SYN-RCVD */
+    if (pcb->state == SYN_RCVD) {
+      if ((u32_t)(tcp_ticks - pcb->tmr) >
+          TCP_SYN_RCVD_TIMEOUT / TCP_SLOW_INTERVAL) {
+        ++pcb_remove;
+        LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in SYN-RCVD\n"));
+      }
+    }
+
+    /* Check if this PCB has stayed too long in LAST-ACK */
+    if (pcb->state == LAST_ACK) {
+      if ((u32_t)(tcp_ticks - pcb->tmr) > 2 * TCP_MSL / TCP_SLOW_INTERVAL) {
+        ++pcb_remove;
+        LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in LAST-ACK\n"));
+      }
+    }
+
+    /* If the PCB should be removed, do it. */
+    if (pcb_remove) {
+      struct tcp_pcb *pcb2;
+      tcp_pcb_purge(pcb);
+      /* Remove PCB from tcp_active_pcbs list. */
+      if (prev != NULL) {
+        LWIP_ASSERT("tcp_slowtmr: middle tcp != tcp_active_pcbs", pcb != tcp_active_pcbs);
+        prev->next = pcb->next;
+      } else {
+        /* This PCB was the first. */
+        LWIP_ASSERT("tcp_slowtmr: first pcb == tcp_active_pcbs", tcp_active_pcbs == pcb);
+        tcp_active_pcbs = pcb->next;
+      }
+
+      TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_ABRT);
+      if (pcb_reset) {
+        tcp_rst(pcb->snd_nxt, pcb->rcv_nxt, &pcb->local_ip, &pcb->remote_ip,
+          pcb->local_port, pcb->remote_port);
+      }
+
+      pcb2 = pcb;
+      pcb = pcb->next;
+      memp_free(MEMP_TCP_PCB, pcb2);
+    } else {
+      /* get the 'next' element now and work with 'prev' below (in case of abort) */
+      prev = pcb;
+      pcb = pcb->next;
+
+      /* We check if we should poll the connection. */
+      ++prev->polltmr;
+      if (prev->polltmr >= prev->pollinterval) {
+        prev->polltmr = 0;
+        LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: polling application\n"));
+        TCP_EVENT_POLL(prev, err);
+        /* if err == ERR_ABRT, 'prev' is already deallocated */
+        if (err == ERR_OK) {
+          tcp_output(prev);
+        }
+      }
+    }
+  }
+
+  
+  /* Steps through all of the TIME-WAIT PCBs. */
+  prev = NULL;
+  pcb = tcp_tw_pcbs;
+  while (pcb != NULL) {
+    LWIP_ASSERT("tcp_slowtmr: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
+    pcb_remove = 0;
+
+    /* Check if this PCB has stayed long enough in TIME-WAIT */
+    if ((u32_t)(tcp_ticks - pcb->tmr) > 2 * TCP_MSL / TCP_SLOW_INTERVAL) {
+      ++pcb_remove;
+    }
+    
+
+
+    /* If the PCB should be removed, do it. */
+    if (pcb_remove) {
+      struct tcp_pcb *pcb2;
+      tcp_pcb_purge(pcb);
+      /* Remove PCB from tcp_tw_pcbs list. */
+      if (prev != NULL) {
+        LWIP_ASSERT("tcp_slowtmr: middle tcp != tcp_tw_pcbs", pcb != tcp_tw_pcbs);
+        prev->next = pcb->next;
+      } else {
+        /* This PCB was the first. */
+        LWIP_ASSERT("tcp_slowtmr: first pcb == tcp_tw_pcbs", tcp_tw_pcbs == pcb);
+        tcp_tw_pcbs = pcb->next;
+      }
+      pcb2 = pcb;
+      pcb = pcb->next;
+      memp_free(MEMP_TCP_PCB, pcb2);
+    } else {
+      prev = pcb;
+      pcb = pcb->next;
+    }
+  }
+}
+
+/**
+ * Is called every TCP_FAST_INTERVAL (250 ms) and process data previously
+ * "refused" by upper layer (application) and sends delayed ACKs.
+ *
+ * Automatically called from tcp_tmr().
+ */
+void
+tcp_fasttmr(void)
+{
+  struct tcp_pcb *pcb = tcp_active_pcbs;
+
+  while(pcb != NULL) {
+    struct tcp_pcb *next = pcb->next;
+    /* If there is data which was previously "refused" by upper layer */
+    if (pcb->refused_data != NULL) {
+      /* Notify again application with data previously received. */
+      err_t err;
+      LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_fasttmr: notify kept packet\n"));
+      TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err);
+      if (err == ERR_OK) {
+        pcb->refused_data = NULL;
+      } else if (err == ERR_ABRT) {
+        /* if err == ERR_ABRT, 'pcb' is already deallocated */
+        pcb = NULL;
+      }
+    }
+
+    /* send delayed ACKs */
+    if (pcb && (pcb->flags & TF_ACK_DELAY)) {
+      LWIP_DEBUGF(TCP_DEBUG, ("tcp_fasttmr: delayed ACK\n"));
+      tcp_ack_now(pcb);
+      tcp_output(pcb);
+      pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
+    }
+
+    pcb = next;
+  }
+}
+
+/**
+ * Deallocates a list of TCP segments (tcp_seg structures).
+ *
+ * @param seg tcp_seg list of TCP segments to free
+ */
+void
+tcp_segs_free(struct tcp_seg *seg)
+{
+  while (seg != NULL) {
+    struct tcp_seg *next = seg->next;
+    tcp_seg_free(seg);
+    seg = next;
+  }
+}
+
+/**
+ * Frees a TCP segment (tcp_seg structure).
+ *
+ * @param seg single tcp_seg to free
+ */
+void
+tcp_seg_free(struct tcp_seg *seg)
+{
+  if (seg != NULL) {
+    if (seg->p != NULL) {
+      pbuf_free(seg->p);
+#if TCP_DEBUG
+      seg->p = NULL;
+#endif /* TCP_DEBUG */
+    }
+    memp_free(MEMP_TCP_SEG, seg);
+  }
+}
+
+/**
+ * Sets the priority of a connection.
+ *
+ * @param pcb the tcp_pcb to manipulate
+ * @param prio new priority
+ */
+void
+tcp_setprio(struct tcp_pcb *pcb, u8_t prio)
+{
+  pcb->prio = prio;
+}
+
+#if TCP_QUEUE_OOSEQ
+/**
+ * Returns a copy of the given TCP segment.
+ * The pbuf and data are not copied, only the pointers
+ *
+ * @param seg the old tcp_seg
+ * @return a copy of seg
+ */ 
+struct tcp_seg *
+tcp_seg_copy(struct tcp_seg *seg)
+{
+  struct tcp_seg *cseg;
+
+  cseg = (struct tcp_seg *)memp_malloc(MEMP_TCP_SEG);
+  if (cseg == NULL) {
+    return NULL;
+  }
+  SMEMCPY((u8_t *)cseg, (const u8_t *)seg, sizeof(struct tcp_seg)); 
+  pbuf_ref(cseg->p);
+  return cseg;
+}
+#endif /* TCP_QUEUE_OOSEQ */
+
+#if LWIP_CALLBACK_API
+/**
+ * Default receive callback that is called if the user didn't register
+ * a recv callback for the pcb.
+ */
+err_t
+tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
+{
+  LWIP_UNUSED_ARG(arg);
+  if (p != NULL) {
+    tcp_recved(pcb, p->tot_len);
+    pbuf_free(p);
+  } else if (err == ERR_OK) {
+    return tcp_close(pcb);
+  }
+  return ERR_OK;
+}
+#endif /* LWIP_CALLBACK_API */
+
+/**
+ * Kills the oldest active connection that has lower priority than prio.
+ *
+ * @param prio minimum priority
+ */
+static void
+tcp_kill_prio(u8_t prio)
+{
+  struct tcp_pcb *pcb, *inactive;
+  u32_t inactivity;
+  u8_t mprio;
+
+
+  mprio = TCP_PRIO_MAX;
+  
+  /* We kill the oldest active connection that has lower priority than prio. */
+  inactivity = 0;
+  inactive = NULL;
+  for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
+    if (pcb->prio <= prio &&
+       pcb->prio <= mprio &&
+       (u32_t)(tcp_ticks - pcb->tmr) >= inactivity) {
+      inactivity = tcp_ticks - pcb->tmr;
+      inactive = pcb;
+      mprio = pcb->prio;
+    }
+  }
+  if (inactive != NULL) {
+    LWIP_DEBUGF(TCP_DEBUG, ("tcp_kill_prio: killing oldest PCB %p (%"S32_F")\n",
+           (void *)inactive, inactivity));
+    tcp_abort(inactive);
+  }
+}
+
+/**
+ * Kills the oldest connection that is in TIME_WAIT state.
+ * Called from tcp_alloc() if no more connections are available.
+ */
+static void
+tcp_kill_timewait(void)
+{
+  struct tcp_pcb *pcb, *inactive;
+  u32_t inactivity;
+
+  inactivity = 0;
+  inactive = NULL;
+  /* Go through the list of TIME_WAIT pcbs and get the oldest pcb. */
+  for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
+    if ((u32_t)(tcp_ticks - pcb->tmr) >= inactivity) {
+      inactivity = tcp_ticks - pcb->tmr;
+      inactive = pcb;
+    }
+  }
+  if (inactive != NULL) {
+    LWIP_DEBUGF(TCP_DEBUG, ("tcp_kill_timewait: killing oldest TIME-WAIT PCB %p (%"S32_F")\n",
+           (void *)inactive, inactivity));
+    tcp_abort(inactive);
+  }
+}
+
+/**
+ * Allocate a new tcp_pcb structure.
+ *
+ * @param prio priority for the new pcb
+ * @return a new tcp_pcb that initially is in state CLOSED
+ */
+struct tcp_pcb *
+tcp_alloc(u8_t prio)
+{
+  struct tcp_pcb *pcb;
+  u32_t iss;
+  
+  pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB);
+  if (pcb == NULL) {
+    /* Try killing oldest connection in TIME-WAIT. */
+    LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing off oldest TIME-WAIT connection\n"));
+    tcp_kill_timewait();
+    /* Try to allocate a tcp_pcb again. */
+    pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB);
+    if (pcb == NULL) {
+      /* Try killing active connections with lower priority than the new one. */
+      LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing connection with prio lower than %d\n", prio));
+      tcp_kill_prio(prio);
+      /* Try to allocate a tcp_pcb again. */
+      pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB);
+      if (pcb != NULL) {
+        /* adjust err stats: memp_malloc failed twice before */
+        MEMP_STATS_DEC(err, MEMP_TCP_PCB);
+      }
+    }
+    if (pcb != NULL) {
+      /* adjust err stats: timewait PCB was freed above */
+      MEMP_STATS_DEC(err, MEMP_TCP_PCB);
+    }
+  }
+  if (pcb != NULL) {
+    memset(pcb, 0, sizeof(struct tcp_pcb));
+    pcb->prio = prio;
+    pcb->snd_buf = TCP_SND_BUF;
+    pcb->snd_queuelen = 0;
+    pcb->rcv_wnd = TCP_WND;
+    pcb->rcv_ann_wnd = TCP_WND;
+    pcb->tos = 0;
+    pcb->ttl = TCP_TTL;
+    /* As initial send MSS, we use TCP_MSS but limit it to 536.
+       The send MSS is updated when an MSS option is received. */
+    pcb->mss = (TCP_MSS > 536) ? 536 : TCP_MSS;
+    pcb->rto = 3000 / TCP_SLOW_INTERVAL;
+    pcb->sa = 0;
+    pcb->sv = 3000 / TCP_SLOW_INTERVAL;
+    pcb->rtime = -1;
+    pcb->cwnd = 1;
+    iss = tcp_next_iss();
+    pcb->snd_wl2 = iss;
+    pcb->snd_nxt = iss;
+    pcb->lastack = iss;
+    pcb->snd_lbb = iss;   
+    pcb->tmr = tcp_ticks;
+
+    pcb->polltmr = 0;
+
+#if LWIP_CALLBACK_API
+    pcb->recv = tcp_recv_null;
+#endif /* LWIP_CALLBACK_API */  
+    
+    /* Init KEEPALIVE timer */
+    pcb->keep_idle  = TCP_KEEPIDLE_DEFAULT;
+    
+#if LWIP_TCP_KEEPALIVE
+    pcb->keep_intvl = TCP_KEEPINTVL_DEFAULT;
+    pcb->keep_cnt   = TCP_KEEPCNT_DEFAULT;
+#endif /* LWIP_TCP_KEEPALIVE */
+
+    pcb->keep_cnt_sent = 0;
+  }
+  return pcb;
+}
+
+/**
+ * Creates a new TCP protocol control block but doesn't place it on
+ * any of the TCP PCB lists.
+ * The pcb is not put on any list until binding using tcp_bind().
+ *
+ * @internal: Maybe there should be a idle TCP PCB list where these
+ * PCBs are put on. Port reservation using tcp_bind() is implemented but
+ * allocated pcbs that are not bound can't be killed automatically if wanting
+ * to allocate a pcb with higher prio (@see tcp_kill_prio())
+ *
+ * @return a new tcp_pcb that initially is in state CLOSED
+ */
+struct tcp_pcb *
+tcp_new(void)
+{
+  return tcp_alloc(TCP_PRIO_NORMAL);
+}
+
+/**
+ * Used to specify the argument that should be passed callback
+ * functions.
+ *
+ * @param pcb tcp_pcb to set the callback argument
+ * @param arg void pointer argument to pass to callback functions
+ */ 
+void
+tcp_arg(struct tcp_pcb *pcb, void *arg)
+{  
+  pcb->callback_arg = arg;
+}
+#if LWIP_CALLBACK_API
+
+/**
+ * Used to specify the function that should be called when a TCP
+ * connection receives data.
+ *
+ * @param pcb tcp_pcb to set the recv callback
+ * @param recv callback function to call for this pcb when data is received
+ */ 
+void
+tcp_recv(struct tcp_pcb *pcb, tcp_recv_fn recv)
+{
+  pcb->recv = recv;
+}
+
+/**
+ * Used to specify the function that should be called when TCP data
+ * has been successfully delivered to the remote host.
+ *
+ * @param pcb tcp_pcb to set the sent callback
+ * @param sent callback function to call for this pcb when data is successfully sent
+ */ 
+void
+tcp_sent(struct tcp_pcb *pcb, tcp_sent_fn sent)
+{
+  pcb->sent = sent;
+}
+
+/**
+ * Used to specify the function that should be called when a fatal error
+ * has occured on the connection.
+ *
+ * @param pcb tcp_pcb to set the err callback
+ * @param err callback function to call for this pcb when a fatal error
+ *        has occured on the connection
+ */ 
+void
+tcp_err(struct tcp_pcb *pcb, tcp_err_fn err)
+{
+  pcb->errf = err;
+}
+
+/**
+ * Used for specifying the function that should be called when a
+ * LISTENing connection has been connected to another host.
+ *
+ * @param pcb tcp_pcb to set the accept callback
+ * @param accept callback function to call for this pcb when LISTENing
+ *        connection has been connected to another host
+ */ 
+void
+tcp_accept(struct tcp_pcb *pcb, tcp_accept_fn accept)
+{
+  pcb->accept = accept;
+}
+#endif /* LWIP_CALLBACK_API */
+
+
+/**
+ * Used to specify the function that should be called periodically
+ * from TCP. The interval is specified in terms of the TCP coarse
+ * timer interval, which is called twice a second.
+ *
+ */ 
+void
+tcp_poll(struct tcp_pcb *pcb, tcp_poll_fn poll, u8_t interval)
+{
+#if LWIP_CALLBACK_API
+  pcb->poll = poll;
+#else /* LWIP_CALLBACK_API */  
+  LWIP_UNUSED_ARG(poll);
+#endif /* LWIP_CALLBACK_API */  
+  pcb->pollinterval = interval;
+}
+
+/**
+ * Purges a TCP PCB. Removes any buffered data and frees the buffer memory
+ * (pcb->ooseq, pcb->unsent and pcb->unacked are freed).
+ *
+ * @param pcb tcp_pcb to purge. The pcb itself is not deallocated!
+ */
+void
+tcp_pcb_purge(struct tcp_pcb *pcb)
+{
+  if (pcb->state != CLOSED &&
+     pcb->state != TIME_WAIT &&
+     pcb->state != LISTEN) {
+
+    LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge\n"));
+
+#if TCP_LISTEN_BACKLOG
+    if (pcb->state == SYN_RCVD) {
+      /* Need to find the corresponding listen_pcb and decrease its accepts_pending */
+      struct tcp_pcb_listen *lpcb;
+      LWIP_ASSERT("tcp_pcb_purge: pcb->state == SYN_RCVD but tcp_listen_pcbs is NULL",
+        tcp_listen_pcbs.listen_pcbs != NULL);
+      for (lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
+        if ((lpcb->local_port == pcb->local_port) &&
+            (ip_addr_isany(&lpcb->local_ip) ||
+             ip_addr_cmp(&pcb->local_ip, &lpcb->local_ip))) {
+            /* port and address of the listen pcb match the timed-out pcb */
+            LWIP_ASSERT("tcp_pcb_purge: listen pcb does not have accepts pending",
+              lpcb->accepts_pending > 0);
+            lpcb->accepts_pending--;
+            break;
+          }
+      }
+    }
+#endif /* TCP_LISTEN_BACKLOG */
+
+
+    if (pcb->refused_data != NULL) {
+      LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->refused_data\n"));
+      pbuf_free(pcb->refused_data);
+      pcb->refused_data = NULL;
+    }
+    if (pcb->unsent != NULL) {
+      LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: not all data sent\n"));
+    }
+    if (pcb->unacked != NULL) {
+      LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->unacked\n"));
+    }
+#if TCP_QUEUE_OOSEQ
+    if (pcb->ooseq != NULL) {
+      LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->ooseq\n"));
+    }
+    tcp_segs_free(pcb->ooseq);
+    pcb->ooseq = NULL;
+#endif /* TCP_QUEUE_OOSEQ */
+
+    /* Stop the retransmission timer as it will expect data on unacked
+       queue if it fires */
+    pcb->rtime = -1;
+
+    tcp_segs_free(pcb->unsent);
+    tcp_segs_free(pcb->unacked);
+    pcb->unacked = pcb->unsent = NULL;
+#if TCP_OVERSIZE
+    pcb->unsent_oversize = 0;
+#endif /* TCP_OVERSIZE */
+  }
+}
+
+/**
+ * Purges the PCB and removes it from a PCB list. Any delayed ACKs are sent first.
+ *
+ * @param pcblist PCB list to purge.
+ * @param pcb tcp_pcb to purge. The pcb itself is NOT deallocated!
+ */
+void
+tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb)
+{
+  TCP_RMV(pcblist, pcb);
+
+  tcp_pcb_purge(pcb);
+  
+  /* if there is an outstanding delayed ACKs, send it */
+  if (pcb->state != TIME_WAIT &&
+     pcb->state != LISTEN &&
+     pcb->flags & TF_ACK_DELAY) {
+    pcb->flags |= TF_ACK_NOW;
+    tcp_output(pcb);
+  }
+
+  if (pcb->state != LISTEN) {
+    LWIP_ASSERT("unsent segments leaking", pcb->unsent == NULL);
+    LWIP_ASSERT("unacked segments leaking", pcb->unacked == NULL);
+#if TCP_QUEUE_OOSEQ
+    LWIP_ASSERT("ooseq segments leaking", pcb->ooseq == NULL);
+#endif /* TCP_QUEUE_OOSEQ */
+  }
+
+  pcb->state = CLOSED;
+
+  LWIP_ASSERT("tcp_pcb_remove: tcp_pcbs_sane()", tcp_pcbs_sane());
+}
+
+/**
+ * Calculates a new initial sequence number for new connections.
+ *
+ * @return u32_t pseudo random sequence number
+ */
+u32_t
+tcp_next_iss(void)
+{
+  static u32_t iss = 6510;
+  
+  iss += tcp_ticks;       /* XXX */
+  return iss;
+}
+
+#if TCP_CALCULATE_EFF_SEND_MSS
+/**
+ * Calcluates the effective send mss that can be used for a specific IP address
+ * by using ip_route to determin the netif used to send to the address and
+ * calculating the minimum of TCP_MSS and that netif's mtu (if set).
+ */
+u16_t
+tcp_eff_send_mss(u16_t sendmss, ip_addr_t *addr)
+{
+  u16_t mss_s;
+  struct netif *outif;
+
+  outif = ip_route(addr);
+  if ((outif != NULL) && (outif->mtu != 0)) {
+    mss_s = outif->mtu - IP_HLEN - TCP_HLEN;
+    /* RFC 1122, chap 4.2.2.6:
+     * Eff.snd.MSS = min(SendMSS+20, MMS_S) - TCPhdrsize - IPoptionsize
+     * We correct for TCP options in tcp_write(), and don't support IP options.
+     */
+    sendmss = LWIP_MIN(sendmss, mss_s);
+  }
+  return sendmss;
+}
+#endif /* TCP_CALCULATE_EFF_SEND_MSS */
+
+const char*
+tcp_debug_state_str(enum tcp_state s)
+{
+  return tcp_state_str[s];
+}
+
+#if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
+/**
+ * Print a tcp header for debugging purposes.
+ *
+ * @param tcphdr pointer to a struct tcp_hdr
+ */
+void
+tcp_debug_print(struct tcp_hdr *tcphdr)
+{
+  LWIP_DEBUGF(TCP_DEBUG, ("TCP header:\n"));
+  LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
+  LWIP_DEBUGF(TCP_DEBUG, ("|    %5"U16_F"      |    %5"U16_F"      | (src port, dest port)\n",
+         ntohs(tcphdr->src), ntohs(tcphdr->dest)));
+  LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
+  LWIP_DEBUGF(TCP_DEBUG, ("|           %010"U32_F"          | (seq no)\n",
+          ntohl(tcphdr->seqno)));
+  LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
+  LWIP_DEBUGF(TCP_DEBUG, ("|           %010"U32_F"          | (ack no)\n",
+         ntohl(tcphdr->ackno)));
+  LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
+  LWIP_DEBUGF(TCP_DEBUG, ("| %2"U16_F" |   |%"U16_F"%"U16_F"%"U16_F"%"U16_F"%"U16_F"%"U16_F"|     %5"U16_F"     | (hdrlen, flags (",
+       TCPH_HDRLEN(tcphdr),
+         TCPH_FLAGS(tcphdr) >> 5 & 1,
+         TCPH_FLAGS(tcphdr) >> 4 & 1,
+         TCPH_FLAGS(tcphdr) >> 3 & 1,
+         TCPH_FLAGS(tcphdr) >> 2 & 1,
+         TCPH_FLAGS(tcphdr) >> 1 & 1,
+         TCPH_FLAGS(tcphdr) & 1,
+         ntohs(tcphdr->wnd)));
+  tcp_debug_print_flags(TCPH_FLAGS(tcphdr));
+  LWIP_DEBUGF(TCP_DEBUG, ("), win)\n"));
+  LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
+  LWIP_DEBUGF(TCP_DEBUG, ("|    0x%04"X16_F"     |     %5"U16_F"     | (chksum, urgp)\n",
+         ntohs(tcphdr->chksum), ntohs(tcphdr->urgp)));
+  LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
+}
+
+/**
+ * Print a tcp state for debugging purposes.
+ *
+ * @param s enum tcp_state to print
+ */
+void
+tcp_debug_print_state(enum tcp_state s)
+{
+  LWIP_DEBUGF(TCP_DEBUG, ("State: %s\n", tcp_state_str[s]));
+}
+
+/**
+ * Print tcp flags for debugging purposes.
+ *
+ * @param flags tcp flags, all active flags are printed
+ */
+void
+tcp_debug_print_flags(u8_t flags)
+{
+  if (flags & TCP_FIN) {
+    LWIP_DEBUGF(TCP_DEBUG, ("FIN "));
+  }
+  if (flags & TCP_SYN) {
+    LWIP_DEBUGF(TCP_DEBUG, ("SYN "));
+  }
+  if (flags & TCP_RST) {
+    LWIP_DEBUGF(TCP_DEBUG, ("RST "));
+  }
+  if (flags & TCP_PSH) {
+    LWIP_DEBUGF(TCP_DEBUG, ("PSH "));
+  }
+  if (flags & TCP_ACK) {
+    LWIP_DEBUGF(TCP_DEBUG, ("ACK "));
+  }
+  if (flags & TCP_URG) {
+    LWIP_DEBUGF(TCP_DEBUG, ("URG "));
+  }
+  if (flags & TCP_ECE) {
+    LWIP_DEBUGF(TCP_DEBUG, ("ECE "));
+  }
+  if (flags & TCP_CWR) {
+    LWIP_DEBUGF(TCP_DEBUG, ("CWR "));
+  }
+  LWIP_DEBUGF(TCP_DEBUG, ("\n"));
+}
+
+/**
+ * Print all tcp_pcbs in every list for debugging purposes.
+ */
+void
+tcp_debug_print_pcbs(void)
+{
+  struct tcp_pcb *pcb;
+  LWIP_DEBUGF(TCP_DEBUG, ("Active PCB states:\n"));
+  for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
+    LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ",
+                       pcb->local_port, pcb->remote_port,
+                       pcb->snd_nxt, pcb->rcv_nxt));
+    tcp_debug_print_state(pcb->state);
+  }    
+  LWIP_DEBUGF(TCP_DEBUG, ("Listen PCB states:\n"));
+  for(pcb = (struct tcp_pcb *)tcp_listen_pcbs.pcbs; pcb != NULL; pcb = pcb->next) {
+    LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ",
+                       pcb->local_port, pcb->remote_port,
+                       pcb->snd_nxt, pcb->rcv_nxt));
+    tcp_debug_print_state(pcb->state);
+  }    
+  LWIP_DEBUGF(TCP_DEBUG, ("TIME-WAIT PCB states:\n"));
+  for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
+    LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ",
+                       pcb->local_port, pcb->remote_port,
+                       pcb->snd_nxt, pcb->rcv_nxt));
+    tcp_debug_print_state(pcb->state);
+  }    
+}
+
+/**
+ * Check state consistency of the tcp_pcb lists.
+ */
+s16_t
+tcp_pcbs_sane(void)
+{
+  struct tcp_pcb *pcb;
+  for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
+    LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != CLOSED", pcb->state != CLOSED);
+    LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != LISTEN", pcb->state != LISTEN);
+    LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT);
+  }
+  for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
+    LWIP_ASSERT("tcp_pcbs_sane: tw pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
+  }
+  return 1;
+}
+#endif /* TCP_DEBUG */
+
+#endif /* LWIP_TCP */
diff --git a/core/lwip/src/core/tcp_in.c b/core/lwip/src/core/tcp_in.c
new file mode 100644
index 00000000..90952648
--- /dev/null
+++ b/core/lwip/src/core/tcp_in.c
@@ -0,0 +1,1567 @@
+/**
+ * @file
+ * Transmission Control Protocol, incoming traffic
+ *
+ * The input processing functions of the TCP layer.
+ *
+ * These functions are generally called in the order (ip_input() ->)
+ * tcp_input() -> * tcp_process() -> tcp_receive() (-> application).
+ * 
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/tcp_impl.h"
+#include "lwip/def.h"
+#include "lwip/ip_addr.h"
+#include "lwip/netif.h"
+#include "lwip/mem.h"
+#include "lwip/memp.h"
+#include "lwip/inet_chksum.h"
+#include "lwip/stats.h"
+#include "lwip/snmp.h"
+#include "arch/perf.h"
+
+/* These variables are global to all functions involved in the input
+   processing of TCP segments. They are set by the tcp_input()
+   function. */
+static struct tcp_seg inseg;
+static struct tcp_hdr *tcphdr;
+static struct ip_hdr *iphdr;
+static u32_t seqno, ackno;
+static u8_t flags;
+static u16_t tcplen;
+
+static u8_t recv_flags;
+static struct pbuf *recv_data;
+
+struct tcp_pcb *tcp_input_pcb;
+
+/* Forward declarations. */
+static err_t tcp_process(struct tcp_pcb *pcb);
+static void tcp_receive(struct tcp_pcb *pcb);
+static void tcp_parseopt(struct tcp_pcb *pcb);
+
+static err_t tcp_listen_input(struct tcp_pcb_listen *pcb);
+static err_t tcp_timewait_input(struct tcp_pcb *pcb);
+
+/**
+ * The initial input processing of TCP. It verifies the TCP header, demultiplexes
+ * the segment between the PCBs and passes it on to tcp_process(), which implements
+ * the TCP finite state machine. This function is called by the IP layer (in
+ * ip_input()).
+ *
+ * @param p received TCP segment to process (p->payload pointing to the IP header)
+ * @param inp network interface on which this segment was received
+ */
+void
+tcp_input(struct pbuf *p, struct netif *inp)
+{
+  struct tcp_pcb *pcb, *prev;
+  struct tcp_pcb_listen *lpcb;
+#if SO_REUSE
+  struct tcp_pcb *lpcb_prev = NULL;
+  struct tcp_pcb_listen *lpcb_any = NULL;
+#endif /* SO_REUSE */
+  u8_t hdrlen;
+  err_t err;
+
+  PERF_START;
+
+  TCP_STATS_INC(tcp.recv);
+  snmp_inc_tcpinsegs();
+
+  iphdr = (struct ip_hdr *)p->payload;
+  tcphdr = (struct tcp_hdr *)((u8_t *)p->payload + IPH_HL(iphdr) * 4);
+
+#if TCP_INPUT_DEBUG
+  tcp_debug_print(tcphdr);
+#endif
+
+  /* remove header from payload */
+  if (pbuf_header(p, -((s16_t)(IPH_HL(iphdr) * 4))) || (p->tot_len < sizeof(struct tcp_hdr))) {
+    /* drop short packets */
+    LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet (%"U16_F" bytes) discarded\n", p->tot_len));
+    TCP_STATS_INC(tcp.lenerr);
+    TCP_STATS_INC(tcp.drop);
+    snmp_inc_tcpinerrs();
+    pbuf_free(p);
+    return;
+  }
+
+  /* Don't even process incoming broadcasts/multicasts. */
+  if (ip_addr_isbroadcast(&current_iphdr_dest, inp) ||
+      ip_addr_ismulticast(&current_iphdr_dest)) {
+    TCP_STATS_INC(tcp.proterr);
+    TCP_STATS_INC(tcp.drop);
+    snmp_inc_tcpinerrs();
+    pbuf_free(p);
+    return;
+  }
+
+#if CHECKSUM_CHECK_TCP
+  /* Verify TCP checksum. */
+  if (inet_chksum_pseudo(p, ip_current_src_addr(), ip_current_dest_addr(),
+      IP_PROTO_TCP, p->tot_len) != 0) {
+      LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packet discarded due to failing checksum 0x%04"X16_F"\n",
+        inet_chksum_pseudo(p, ip_current_src_addr(), ip_current_dest_addr(),
+      IP_PROTO_TCP, p->tot_len)));
+#if TCP_DEBUG
+    tcp_debug_print(tcphdr);
+#endif /* TCP_DEBUG */
+    TCP_STATS_INC(tcp.chkerr);
+    TCP_STATS_INC(tcp.drop);
+    snmp_inc_tcpinerrs();
+    pbuf_free(p);
+    return;
+  }
+#endif
+
+  /* Move the payload pointer in the pbuf so that it points to the
+     TCP data instead of the TCP header. */
+  hdrlen = TCPH_HDRLEN(tcphdr);
+  if(pbuf_header(p, -(hdrlen * 4))){
+    /* drop short packets */
+    LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet\n"));
+    TCP_STATS_INC(tcp.lenerr);
+    TCP_STATS_INC(tcp.drop);
+    snmp_inc_tcpinerrs();
+    pbuf_free(p);
+    return;
+  }
+
+  /* Convert fields in TCP header to host byte order. */
+  tcphdr->src = ntohs(tcphdr->src);
+  tcphdr->dest = ntohs(tcphdr->dest);
+  seqno = tcphdr->seqno = ntohl(tcphdr->seqno);
+  ackno = tcphdr->ackno = ntohl(tcphdr->ackno);
+  tcphdr->wnd = ntohs(tcphdr->wnd);
+
+  flags = TCPH_FLAGS(tcphdr);
+  tcplen = p->tot_len + ((flags & (TCP_FIN | TCP_SYN)) ? 1 : 0);
+
+  /* Demultiplex an incoming segment. First, we check if it is destined
+     for an active connection. */
+  prev = NULL;
+
+  
+  for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
+    LWIP_ASSERT("tcp_input: active pcb->state != CLOSED", pcb->state != CLOSED);
+    LWIP_ASSERT("tcp_input: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT);
+    LWIP_ASSERT("tcp_input: active pcb->state != LISTEN", pcb->state != LISTEN);
+    if (pcb->remote_port == tcphdr->src &&
+       pcb->local_port == tcphdr->dest &&
+       ip_addr_cmp(&(pcb->remote_ip), &current_iphdr_src) &&
+       ip_addr_cmp(&(pcb->local_ip), &current_iphdr_dest)) {
+
+      /* Move this PCB to the front of the list so that subsequent
+         lookups will be faster (we exploit locality in TCP segment
+         arrivals). */
+      LWIP_ASSERT("tcp_input: pcb->next != pcb (before cache)", pcb->next != pcb);
+      if (prev != NULL) {
+        prev->next = pcb->next;
+        pcb->next = tcp_active_pcbs;
+        tcp_active_pcbs = pcb;
+      }
+      LWIP_ASSERT("tcp_input: pcb->next != pcb (after cache)", pcb->next != pcb);
+      break;
+    }
+    prev = pcb;
+  }
+
+  if (pcb == NULL) {
+    /* If it did not go to an active connection, we check the connections
+       in the TIME-WAIT state. */
+    for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
+      LWIP_ASSERT("tcp_input: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
+      if (pcb->remote_port == tcphdr->src &&
+         pcb->local_port == tcphdr->dest &&
+         ip_addr_cmp(&(pcb->remote_ip), &current_iphdr_src) &&
+         ip_addr_cmp(&(pcb->local_ip), &current_iphdr_dest)) {
+        /* We don't really care enough to move this PCB to the front
+           of the list since we are not very likely to receive that
+           many segments for connections in TIME-WAIT. */
+        LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for TIME_WAITing connection.\n"));
+        tcp_timewait_input(pcb);
+        pbuf_free(p);
+        return;
+      }
+    }
+
+    /* Finally, if we still did not get a match, we check all PCBs that
+       are LISTENing for incoming connections. */
+    prev = NULL;
+    for(lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
+      if (lpcb->local_port == tcphdr->dest) {
+#if SO_REUSE
+        if (ip_addr_cmp(&(lpcb->local_ip), &current_iphdr_dest)) {
+          /* found an exact match */
+          break;
+        } else if(ip_addr_isany(&(lpcb->local_ip))) {
+          /* found an ANY-match */
+          lpcb_any = lpcb;
+          lpcb_prev = prev;
+        }
+#else /* SO_REUSE */
+        if (ip_addr_cmp(&(lpcb->local_ip), &current_iphdr_dest) ||
+            ip_addr_isany(&(lpcb->local_ip))) {
+          /* found a match */
+          break;
+        }
+#endif /* SO_REUSE */
+      }
+      prev = (struct tcp_pcb *)lpcb;
+    }
+#if SO_REUSE
+    /* first try specific local IP */
+    if (lpcb == NULL) {
+      /* only pass to ANY if no specific local IP has been found */
+      lpcb = lpcb_any;
+      prev = lpcb_prev;
+    }
+#endif /* SO_REUSE */
+    if (lpcb != NULL) {
+      /* Move this PCB to the front of the list so that subsequent
+         lookups will be faster (we exploit locality in TCP segment
+         arrivals). */
+      if (prev != NULL) {
+        ((struct tcp_pcb_listen *)prev)->next = lpcb->next;
+              /* our successor is the remainder of the listening list */
+        lpcb->next = tcp_listen_pcbs.listen_pcbs;
+              /* put this listening pcb at the head of the listening list */
+        tcp_listen_pcbs.listen_pcbs = lpcb;
+      }
+    
+      LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for LISTENing connection.\n"));
+      tcp_listen_input(lpcb);
+      pbuf_free(p);
+      return;
+    }
+  }
+
+#if TCP_INPUT_DEBUG
+  LWIP_DEBUGF(TCP_INPUT_DEBUG, ("+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags "));
+  tcp_debug_print_flags(TCPH_FLAGS(tcphdr));
+  LWIP_DEBUGF(TCP_INPUT_DEBUG, ("-+-+-+-+-+-+-+-+-+-+-+-+-+-+\n"));
+#endif /* TCP_INPUT_DEBUG */
+
+
+  if (pcb != NULL) {
+    /* The incoming segment belongs to a connection. */
+#if TCP_INPUT_DEBUG
+#if TCP_DEBUG
+    tcp_debug_print_state(pcb->state);
+#endif /* TCP_DEBUG */
+#endif /* TCP_INPUT_DEBUG */
+
+    /* Set up a tcp_seg structure. */
+    inseg.next = NULL;
+    inseg.len = p->tot_len;
+    inseg.p = p;
+    inseg.tcphdr = tcphdr;
+
+    recv_data = NULL;
+    recv_flags = 0;
+
+    /* If there is data which was previously "refused" by upper layer */
+    if (pcb->refused_data != NULL) {
+      /* Notify again application with data previously received. */
+      LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: notify kept packet\n"));
+      TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err);
+      if (err == ERR_OK) {
+        pcb->refused_data = NULL;
+      } else if ((err == ERR_ABRT) || (tcplen > 0)) {
+        /* if err == ERR_ABRT, 'pcb' is already deallocated */
+        /* Drop incoming packets because pcb is "full" (only if the incoming
+           segment contains data). */
+        LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: drop incoming packets, because pcb is \"full\"\n"));
+        TCP_STATS_INC(tcp.drop);
+        snmp_inc_tcpinerrs();
+        pbuf_free(p);
+        return;
+      }
+    }
+    tcp_input_pcb = pcb;
+    err = tcp_process(pcb);
+    /* A return value of ERR_ABRT means that tcp_abort() was called
+       and that the pcb has been freed. If so, we don't do anything. */
+    if (err != ERR_ABRT) {
+      if (recv_flags & TF_RESET) {
+        /* TF_RESET means that the connection was reset by the other
+           end. We then call the error callback to inform the
+           application that the connection is dead before we
+           deallocate the PCB. */
+        TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_RST);
+        tcp_pcb_remove(&tcp_active_pcbs, pcb);
+        memp_free(MEMP_TCP_PCB, pcb);
+      } else if (recv_flags & TF_CLOSED) {
+        /* The connection has been closed and we will deallocate the
+           PCB. */
+        tcp_pcb_remove(&tcp_active_pcbs, pcb);
+        memp_free(MEMP_TCP_PCB, pcb);
+      } else {
+        err = ERR_OK;
+        /* If the application has registered a "sent" function to be
+           called when new send buffer space is available, we call it
+           now. */
+        if (pcb->acked > 0) {
+          TCP_EVENT_SENT(pcb, pcb->acked, err);
+          if (err == ERR_ABRT) {
+            goto aborted;
+          }
+        }
+
+        if (recv_data != NULL) {
+          LWIP_ASSERT("pcb->refused_data == NULL", pcb->refused_data == NULL);
+          if (pcb->flags & TF_RXCLOSED) {
+            /* received data although already closed -> abort (send RST) to
+               notify the remote host that not all data has been processed */
+            pbuf_free(recv_data);
+            tcp_abort(pcb);
+            goto aborted;
+          }
+          if (flags & TCP_PSH) {
+            recv_data->flags |= PBUF_FLAG_PUSH;
+          }
+
+          /* Notify application that data has been received. */
+          TCP_EVENT_RECV(pcb, recv_data, ERR_OK, err);
+          if (err == ERR_ABRT) {
+            goto aborted;
+          }
+
+          /* If the upper layer can't receive this data, store it */
+          if (err != ERR_OK) {
+            pcb->refused_data = recv_data;
+            LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: keep incoming packet, because pcb is \"full\"\n"));
+          }
+        }
+
+        /* If a FIN segment was received, we call the callback
+           function with a NULL buffer to indicate EOF. */
+        if (recv_flags & TF_GOT_FIN) {
+          /* correct rcv_wnd as the application won't call tcp_recved()
+             for the FIN's seqno */
+          if (pcb->rcv_wnd != TCP_WND) {
+            pcb->rcv_wnd++;
+          }
+          TCP_EVENT_CLOSED(pcb, err);
+          if (err == ERR_ABRT) {
+            goto aborted;
+          }
+        }
+
+        tcp_input_pcb = NULL;
+        /* Try to send something out. */
+        tcp_output(pcb);
+#if TCP_INPUT_DEBUG
+#if TCP_DEBUG
+        tcp_debug_print_state(pcb->state);
+#endif /* TCP_DEBUG */
+#endif /* TCP_INPUT_DEBUG */
+      }
+    }
+    /* Jump target if pcb has been aborted in a callback (by calling tcp_abort()).
+       Below this line, 'pcb' may not be dereferenced! */
+aborted:
+    tcp_input_pcb = NULL;
+    recv_data = NULL;
+
+    /* give up our reference to inseg.p */
+    if (inseg.p != NULL)
+    {
+      pbuf_free(inseg.p);
+      inseg.p = NULL;
+    }
+  } else {
+
+    /* If no matching PCB was found, send a TCP RST (reset) to the
+       sender. */
+    LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_input: no PCB match found, resetting.\n"));
+    if (!(TCPH_FLAGS(tcphdr) & TCP_RST)) {
+      TCP_STATS_INC(tcp.proterr);
+      TCP_STATS_INC(tcp.drop);
+      tcp_rst(ackno, seqno + tcplen,
+        ip_current_dest_addr(), ip_current_src_addr(),
+        tcphdr->dest, tcphdr->src);
+    }
+    pbuf_free(p);
+  }
+
+  LWIP_ASSERT("tcp_input: tcp_pcbs_sane()", tcp_pcbs_sane());
+  PERF_STOP("tcp_input");
+}
+
+/**
+ * Called by tcp_input() when a segment arrives for a listening
+ * connection (from tcp_input()).
+ *
+ * @param pcb the tcp_pcb_listen for which a segment arrived
+ * @return ERR_OK if the segment was processed
+ *         another err_t on error
+ *
+ * @note the return value is not (yet?) used in tcp_input()
+ * @note the segment which arrived is saved in global variables, therefore only the pcb
+ *       involved is passed as a parameter to this function
+ */
+static err_t
+tcp_listen_input(struct tcp_pcb_listen *pcb)
+{
+  struct tcp_pcb *npcb;
+  err_t rc;
+
+  /* In the LISTEN state, we check for incoming SYN segments,
+     creates a new PCB, and responds with a SYN|ACK. */
+  if (flags & TCP_ACK) {
+    /* For incoming segments with the ACK flag set, respond with a
+       RST. */
+    LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_listen_input: ACK in LISTEN, sending reset\n"));
+    tcp_rst(ackno + 1, seqno + tcplen,
+      ip_current_dest_addr(), ip_current_src_addr(),
+      tcphdr->dest, tcphdr->src);
+  } else if (flags & TCP_SYN) {
+    LWIP_DEBUGF(TCP_DEBUG, ("TCP connection request %"U16_F" -> %"U16_F".\n", tcphdr->src, tcphdr->dest));
+#if TCP_LISTEN_BACKLOG
+    if (pcb->accepts_pending >= pcb->backlog) {
+      LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: listen backlog exceeded for port %"U16_F"\n", tcphdr->dest));
+      return ERR_ABRT;
+    }
+#endif /* TCP_LISTEN_BACKLOG */
+    npcb = tcp_alloc(pcb->prio);
+    /* If a new PCB could not be created (probably due to lack of memory),
+       we don't do anything, but rely on the sender will retransmit the
+       SYN at a time when we have more memory available. */
+    if (npcb == NULL) {
+      LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: could not allocate PCB\n"));
+      TCP_STATS_INC(tcp.memerr);
+      return ERR_MEM;
+    }
+#if TCP_LISTEN_BACKLOG
+    pcb->accepts_pending++;
+#endif /* TCP_LISTEN_BACKLOG */
+    /* Set up the new PCB. */
+    ip_addr_copy(npcb->local_ip, current_iphdr_dest);
+    npcb->local_port = pcb->local_port;
+    ip_addr_copy(npcb->remote_ip, current_iphdr_src);
+    npcb->remote_port = tcphdr->src;
+    npcb->state = SYN_RCVD;
+    npcb->rcv_nxt = seqno + 1;
+    npcb->rcv_ann_right_edge = npcb->rcv_nxt;
+    npcb->snd_wnd = tcphdr->wnd;
+    npcb->ssthresh = npcb->snd_wnd;
+    npcb->snd_wl1 = seqno - 1;/* initialise to seqno-1 to force window update */
+    npcb->callback_arg = pcb->callback_arg;
+#if LWIP_CALLBACK_API
+    npcb->accept = pcb->accept;
+#endif /* LWIP_CALLBACK_API */
+    /* inherit socket options */
+    npcb->so_options = pcb->so_options & SOF_INHERITED;
+    /* Register the new PCB so that we can begin receiving segments
+       for it. */
+    TCP_REG(&tcp_active_pcbs, npcb);
+
+    /* Parse any options in the SYN. */
+    tcp_parseopt(npcb);
+#if TCP_CALCULATE_EFF_SEND_MSS
+    npcb->mss = tcp_eff_send_mss(npcb->mss, &(npcb->remote_ip));
+#endif /* TCP_CALCULATE_EFF_SEND_MSS */
+
+    snmp_inc_tcppassiveopens();
+
+    /* Send a SYN|ACK together with the MSS option. */
+    rc = tcp_enqueue_flags(npcb, TCP_SYN | TCP_ACK);
+    if (rc != ERR_OK) {
+      tcp_abandon(npcb, 0);
+      return rc;
+    }
+    return tcp_output(npcb);
+  }
+  return ERR_OK;
+}
+
+/**
+ * Called by tcp_input() when a segment arrives for a connection in
+ * TIME_WAIT.
+ *
+ * @param pcb the tcp_pcb for which a segment arrived
+ *
+ * @note the segment which arrived is saved in global variables, therefore only the pcb
+ *       involved is passed as a parameter to this function
+ */
+static err_t
+tcp_timewait_input(struct tcp_pcb *pcb)
+{
+  /* RFC 1337: in TIME_WAIT, ignore RST and ACK FINs + any 'acceptable' segments */
+  /* RFC 793 3.9 Event Processing - Segment Arrives:
+   * - first check sequence number - we skip that one in TIME_WAIT (always
+   *   acceptable since we only send ACKs)
+   * - second check the RST bit (... return) */
+  if (flags & TCP_RST)  {
+    return ERR_OK;
+  }
+  /* - fourth, check the SYN bit, */
+  if (flags & TCP_SYN) {
+    /* If an incoming segment is not acceptable, an acknowledgment
+       should be sent in reply */
+    if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt+pcb->rcv_wnd)) {
+      /* If the SYN is in the window it is an error, send a reset */
+      tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
+        tcphdr->dest, tcphdr->src);
+      return ERR_OK;
+    }
+  } else if (flags & TCP_FIN) {
+    /* - eighth, check the FIN bit: Remain in the TIME-WAIT state.
+         Restart the 2 MSL time-wait timeout.*/
+    pcb->tmr = tcp_ticks;
+  }
+
+  if ((tcplen > 0))  {
+    /* Acknowledge data, FIN or out-of-window SYN */
+    pcb->flags |= TF_ACK_NOW;
+    return tcp_output(pcb);
+  }
+  return ERR_OK;
+}
+
+/**
+ * Implements the TCP state machine. Called by tcp_input. In some
+ * states tcp_receive() is called to receive data. The tcp_seg
+ * argument will be freed by the caller (tcp_input()) unless the
+ * recv_data pointer in the pcb is set.
+ *
+ * @param pcb the tcp_pcb for which a segment arrived
+ *
+ * @note the segment which arrived is saved in global variables, therefore only the pcb
+ *       involved is passed as a parameter to this function
+ */
+static err_t
+tcp_process(struct tcp_pcb *pcb)
+{
+  struct tcp_seg *rseg;
+  u8_t acceptable = 0;
+  err_t err;
+
+  err = ERR_OK;
+
+  /* Process incoming RST segments. */
+  if (flags & TCP_RST) {
+    /* First, determine if the reset is acceptable. */
+    if (pcb->state == SYN_SENT) {
+      if (ackno == pcb->snd_nxt) {
+        acceptable = 1;
+      }
+    } else {
+      if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, 
+                          pcb->rcv_nxt+pcb->rcv_wnd)) {
+        acceptable = 1;
+      }
+    }
+
+    if (acceptable) {
+      LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: Connection RESET\n"));
+      LWIP_ASSERT("tcp_input: pcb->state != CLOSED", pcb->state != CLOSED);
+      recv_flags |= TF_RESET;
+      pcb->flags &= ~TF_ACK_DELAY;
+      return ERR_RST;
+    } else {
+      LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
+       seqno, pcb->rcv_nxt));
+      LWIP_DEBUGF(TCP_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
+       seqno, pcb->rcv_nxt));
+      return ERR_OK;
+    }
+  }
+
+  if ((flags & TCP_SYN) && (pcb->state != SYN_SENT && pcb->state != SYN_RCVD)) { 
+    /* Cope with new connection attempt after remote end crashed */
+    tcp_ack_now(pcb);
+    return ERR_OK;
+  }
+  
+  if ((pcb->flags & TF_RXCLOSED) == 0) {
+    /* Update the PCB (in)activity timer unless rx is closed (see tcp_shutdown) */
+    pcb->tmr = tcp_ticks;
+  }
+  pcb->keep_cnt_sent = 0;
+
+  tcp_parseopt(pcb);
+
+  /* Do different things depending on the TCP state. */
+  switch (pcb->state) {
+  case SYN_SENT:
+    LWIP_DEBUGF(TCP_INPUT_DEBUG, ("SYN-SENT: ackno %"U32_F" pcb->snd_nxt %"U32_F" unacked %"U32_F"\n", ackno,
+     pcb->snd_nxt, ntohl(pcb->unacked->tcphdr->seqno)));
+    /* received SYN ACK with expected sequence number? */
+    if ((flags & TCP_ACK) && (flags & TCP_SYN)
+        && ackno == ntohl(pcb->unacked->tcphdr->seqno) + 1) {
+      pcb->snd_buf++;
+      pcb->rcv_nxt = seqno + 1;
+      pcb->rcv_ann_right_edge = pcb->rcv_nxt;
+      pcb->lastack = ackno;
+      pcb->snd_wnd = tcphdr->wnd;
+      pcb->snd_wl1 = seqno - 1; /* initialise to seqno - 1 to force window update */
+      pcb->state = ESTABLISHED;
+
+#if TCP_CALCULATE_EFF_SEND_MSS
+      pcb->mss = tcp_eff_send_mss(pcb->mss, &(pcb->remote_ip));
+#endif /* TCP_CALCULATE_EFF_SEND_MSS */
+
+      /* Set ssthresh again after changing pcb->mss (already set in tcp_connect
+       * but for the default value of pcb->mss) */
+      pcb->ssthresh = pcb->mss * 10;
+
+      pcb->cwnd = ((pcb->cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
+      LWIP_ASSERT("pcb->snd_queuelen > 0", (pcb->snd_queuelen > 0));
+      --pcb->snd_queuelen;
+      LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_process: SYN-SENT --queuelen %"U16_F"\n", (u16_t)pcb->snd_queuelen));
+      rseg = pcb->unacked;
+      pcb->unacked = rseg->next;
+
+      /* If there's nothing left to acknowledge, stop the retransmit
+         timer, otherwise reset it to start again */
+      if(pcb->unacked == NULL)
+        pcb->rtime = -1;
+      else {
+        pcb->rtime = 0;
+        pcb->nrtx = 0;
+      }
+
+      tcp_seg_free(rseg);
+
+      /* Call the user specified function to call when sucessfully
+       * connected. */
+      TCP_EVENT_CONNECTED(pcb, ERR_OK, err);
+      if (err == ERR_ABRT) {
+        return ERR_ABRT;
+      }
+      tcp_ack_now(pcb);
+    }
+    /* received ACK? possibly a half-open connection */
+    else if (flags & TCP_ACK) {
+      /* send a RST to bring the other side in a non-synchronized state. */
+      tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
+        tcphdr->dest, tcphdr->src);
+    }
+    break;
+  case SYN_RCVD:
+    if (flags & TCP_ACK) {
+      /* expected ACK number? */
+      if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)) {
+        u16_t old_cwnd;
+        pcb->state = ESTABLISHED;
+        LWIP_DEBUGF(TCP_DEBUG, ("TCP connection established %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
+#if LWIP_CALLBACK_API
+        LWIP_ASSERT("pcb->accept != NULL", pcb->accept != NULL);
+#endif
+        /* Call the accept function. */
+        TCP_EVENT_ACCEPT(pcb, ERR_OK, err);
+        if (err != ERR_OK) {
+          /* If the accept function returns with an error, we abort
+           * the connection. */
+          /* Already aborted? */
+          if (err != ERR_ABRT) {
+            tcp_abort(pcb);
+          }
+          return ERR_ABRT;
+        }
+        old_cwnd = pcb->cwnd;
+        /* If there was any data contained within this ACK,
+         * we'd better pass it on to the application as well. */
+        tcp_receive(pcb);
+
+        /* Prevent ACK for SYN to generate a sent event */
+        if (pcb->acked != 0) {
+          pcb->acked--;
+        }
+
+        pcb->cwnd = ((old_cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
+
+        if (recv_flags & TF_GOT_FIN) {
+          tcp_ack_now(pcb);
+          pcb->state = CLOSE_WAIT;
+        }
+      } else {
+        /* incorrect ACK number, send RST */
+        tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
+                tcphdr->dest, tcphdr->src);
+      }
+    } else if ((flags & TCP_SYN) && (seqno == pcb->rcv_nxt - 1)) {
+      /* Looks like another copy of the SYN - retransmit our SYN-ACK */
+      tcp_rexmit(pcb);
+    }
+    break;
+  case CLOSE_WAIT:
+    /* FALLTHROUGH */
+  case ESTABLISHED:
+    tcp_receive(pcb);
+    if (recv_flags & TF_GOT_FIN) { /* passive close */
+      tcp_ack_now(pcb);
+      pcb->state = CLOSE_WAIT;
+    }
+    break;
+  case FIN_WAIT_1:
+    tcp_receive(pcb);
+    if (recv_flags & TF_GOT_FIN) {
+      if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
+        LWIP_DEBUGF(TCP_DEBUG,
+          ("TCP connection closed: FIN_WAIT_1 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
+        tcp_ack_now(pcb);
+        tcp_pcb_purge(pcb);
+        TCP_RMV(&tcp_active_pcbs, pcb);
+        pcb->state = TIME_WAIT;
+        TCP_REG(&tcp_tw_pcbs, pcb);
+      } else {
+        tcp_ack_now(pcb);
+        pcb->state = CLOSING;
+      }
+    } else if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
+      pcb->state = FIN_WAIT_2;
+    }
+    break;
+  case FIN_WAIT_2:
+    tcp_receive(pcb);
+    if (recv_flags & TF_GOT_FIN) {
+      LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: FIN_WAIT_2 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
+      tcp_ack_now(pcb);
+      tcp_pcb_purge(pcb);
+      TCP_RMV(&tcp_active_pcbs, pcb);
+      pcb->state = TIME_WAIT;
+      TCP_REG(&tcp_tw_pcbs, pcb);
+    }
+    break;
+  case CLOSING:
+    tcp_receive(pcb);
+    if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
+      LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: CLOSING %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
+      tcp_pcb_purge(pcb);
+      TCP_RMV(&tcp_active_pcbs, pcb);
+      pcb->state = TIME_WAIT;
+      TCP_REG(&tcp_tw_pcbs, pcb);
+    }
+    break;
+  case LAST_ACK:
+    tcp_receive(pcb);
+    if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
+      LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: LAST_ACK %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
+      /* bugfix #21699: don't set pcb->state to CLOSED here or we risk leaking segments */
+      recv_flags |= TF_CLOSED;
+    }
+    break;
+  default:
+    break;
+  }
+  return ERR_OK;
+}
+
+#if TCP_QUEUE_OOSEQ
+/**
+ * Insert segment into the list (segments covered with new one will be deleted)
+ *
+ * Called from tcp_receive()
+ */
+static void
+tcp_oos_insert_segment(struct tcp_seg *cseg, struct tcp_seg *next)
+{
+  struct tcp_seg *old_seg;
+
+  if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
+    /* received segment overlaps all following segments */
+    tcp_segs_free(next);
+    next = NULL;
+  }
+  else {
+    /* delete some following segments
+       oos queue may have segments with FIN flag */
+    while (next &&
+           TCP_SEQ_GEQ((seqno + cseg->len),
+                      (next->tcphdr->seqno + next->len))) {
+      /* cseg with FIN already processed */
+      if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) {
+        TCPH_SET_FLAG(cseg->tcphdr, TCP_FIN);
+      }
+      old_seg = next;
+      next = next->next;
+      tcp_seg_free(old_seg);
+    }
+    if (next &&
+        TCP_SEQ_GT(seqno + cseg->len, next->tcphdr->seqno)) {
+      /* We need to trim the incoming segment. */
+      cseg->len = (u16_t)(next->tcphdr->seqno - seqno);
+      pbuf_realloc(cseg->p, cseg->len);
+    }
+  }
+  cseg->next = next;
+}
+#endif /* TCP_QUEUE_OOSEQ */
+
+/**
+ * Called by tcp_process. Checks if the given segment is an ACK for outstanding
+ * data, and if so frees the memory of the buffered data. Next, is places the
+ * segment on any of the receive queues (pcb->recved or pcb->ooseq). If the segment
+ * is buffered, the pbuf is referenced by pbuf_ref so that it will not be freed until
+ * i it has been removed from the buffer.
+ *
+ * If the incoming segment constitutes an ACK for a segment that was used for RTT
+ * estimation, the RTT is estimated here as well.
+ *
+ * Called from tcp_process().
+ */
+static void
+tcp_receive(struct tcp_pcb *pcb)
+{
+  struct tcp_seg *next;
+#if TCP_QUEUE_OOSEQ
+  struct tcp_seg *prev, *cseg;
+#endif /* TCP_QUEUE_OOSEQ */
+  struct pbuf *p;
+  s32_t off;
+  s16_t m;
+  u32_t right_wnd_edge;
+  u16_t new_tot_len;
+  int found_dupack = 0;
+
+  if (flags & TCP_ACK) {
+    right_wnd_edge = pcb->snd_wnd + pcb->snd_wl2;
+
+    /* Update window. */
+    if (TCP_SEQ_LT(pcb->snd_wl1, seqno) ||
+       (pcb->snd_wl1 == seqno && TCP_SEQ_LT(pcb->snd_wl2, ackno)) ||
+       (pcb->snd_wl2 == ackno && tcphdr->wnd > pcb->snd_wnd)) {
+      pcb->snd_wnd = tcphdr->wnd;
+      pcb->snd_wl1 = seqno;
+      pcb->snd_wl2 = ackno;
+      if (pcb->snd_wnd > 0 && pcb->persist_backoff > 0) {
+          pcb->persist_backoff = 0;
+      }
+      LWIP_DEBUGF(TCP_WND_DEBUG, ("tcp_receive: window update %"U16_F"\n", pcb->snd_wnd));
+#if TCP_WND_DEBUG
+    } else {
+      if (pcb->snd_wnd != tcphdr->wnd) {
+        LWIP_DEBUGF(TCP_WND_DEBUG, 
+                    ("tcp_receive: no window update lastack %"U32_F" ackno %"
+                     U32_F" wl1 %"U32_F" seqno %"U32_F" wl2 %"U32_F"\n",
+                     pcb->lastack, ackno, pcb->snd_wl1, seqno, pcb->snd_wl2));
+      }
+#endif /* TCP_WND_DEBUG */
+    }
+
+    /* (From Stevens TCP/IP Illustrated Vol II, p970.) Its only a
+     * duplicate ack if:
+     * 1) It doesn't ACK new data 
+     * 2) length of received packet is zero (i.e. no payload) 
+     * 3) the advertised window hasn't changed 
+     * 4) There is outstanding unacknowledged data (retransmission timer running)
+     * 5) The ACK is == biggest ACK sequence number so far seen (snd_una)
+     * 
+     * If it passes all five, should process as a dupack: 
+     * a) dupacks < 3: do nothing 
+     * b) dupacks == 3: fast retransmit 
+     * c) dupacks > 3: increase cwnd 
+     * 
+     * If it only passes 1-3, should reset dupack counter (and add to
+     * stats, which we don't do in lwIP)
+     *
+     * If it only passes 1, should reset dupack counter
+     *
+     */
+
+    /* Clause 1 */
+    if (TCP_SEQ_LEQ(ackno, pcb->lastack)) {
+      pcb->acked = 0;
+      /* Clause 2 */
+      if (tcplen == 0) {
+        /* Clause 3 */
+        if (pcb->snd_wl2 + pcb->snd_wnd == right_wnd_edge){
+          /* Clause 4 */
+          if (pcb->rtime >= 0) {
+            /* Clause 5 */
+            if (pcb->lastack == ackno) {
+              found_dupack = 1;
+              if (pcb->dupacks + 1 > pcb->dupacks)
+                ++pcb->dupacks;
+              if (pcb->dupacks > 3) {
+                /* Inflate the congestion window, but not if it means that
+                   the value overflows. */
+                if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
+                  pcb->cwnd += pcb->mss;
+                }
+              } else if (pcb->dupacks == 3) {
+                /* Do fast retransmit */
+                tcp_rexmit_fast(pcb);
+              }
+            }
+          }
+        }
+      }
+      /* If Clause (1) or more is true, but not a duplicate ack, reset
+       * count of consecutive duplicate acks */
+      if (!found_dupack) {
+        pcb->dupacks = 0;
+      }
+    } else if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)){
+      /* We come here when the ACK acknowledges new data. */
+
+      /* Reset the "IN Fast Retransmit" flag, since we are no longer
+         in fast retransmit. Also reset the congestion window to the
+         slow start threshold. */
+      if (pcb->flags & TF_INFR) {
+        pcb->flags &= ~TF_INFR;
+        pcb->cwnd = pcb->ssthresh;
+      }
+
+      /* Reset the number of retransmissions. */
+      pcb->nrtx = 0;
+
+      /* Reset the retransmission time-out. */
+      pcb->rto = (pcb->sa >> 3) + pcb->sv;
+
+      /* Update the send buffer space. Diff between the two can never exceed 64K? */
+      pcb->acked = (u16_t)(ackno - pcb->lastack);
+
+      pcb->snd_buf += pcb->acked;
+
+      /* Reset the fast retransmit variables. */
+      pcb->dupacks = 0;
+      pcb->lastack = ackno;
+
+      /* Update the congestion control variables (cwnd and
+         ssthresh). */
+      if (pcb->state >= ESTABLISHED) {
+        if (pcb->cwnd < pcb->ssthresh) {
+          if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
+            pcb->cwnd += pcb->mss;
+          }
+          LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: slow start cwnd %"U16_F"\n", pcb->cwnd));
+        } else {
+          u16_t new_cwnd = (pcb->cwnd + pcb->mss * pcb->mss / pcb->cwnd);
+          if (new_cwnd > pcb->cwnd) {
+            pcb->cwnd = new_cwnd;
+          }
+          LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: congestion avoidance cwnd %"U16_F"\n", pcb->cwnd));
+        }
+      }
+      LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: ACK for %"U32_F", unacked->seqno %"U32_F":%"U32_F"\n",
+                                    ackno,
+                                    pcb->unacked != NULL?
+                                    ntohl(pcb->unacked->tcphdr->seqno): 0,
+                                    pcb->unacked != NULL?
+                                    ntohl(pcb->unacked->tcphdr->seqno) + TCP_TCPLEN(pcb->unacked): 0));
+
+      /* Remove segment from the unacknowledged list if the incoming
+         ACK acknowlegdes them. */
+      while (pcb->unacked != NULL &&
+             TCP_SEQ_LEQ(ntohl(pcb->unacked->tcphdr->seqno) +
+                         TCP_TCPLEN(pcb->unacked), ackno)) {
+        LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unacked\n",
+                                      ntohl(pcb->unacked->tcphdr->seqno),
+                                      ntohl(pcb->unacked->tcphdr->seqno) +
+                                      TCP_TCPLEN(pcb->unacked)));
+
+        next = pcb->unacked;
+        pcb->unacked = pcb->unacked->next;
+
+        LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
+        LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
+        /* Prevent ACK for FIN to generate a sent event */
+        if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
+          pcb->acked--;
+        }
+
+        pcb->snd_queuelen -= pbuf_clen(next->p);
+        tcp_seg_free(next);
+
+        LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unacked)\n", (u16_t)pcb->snd_queuelen));
+        if (pcb->snd_queuelen != 0) {
+          LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL ||
+                      pcb->unsent != NULL);
+        }
+      }
+
+      /* If there's nothing left to acknowledge, stop the retransmit
+         timer, otherwise reset it to start again */
+      if(pcb->unacked == NULL)
+        pcb->rtime = -1;
+      else
+        pcb->rtime = 0;
+
+      pcb->polltmr = 0;
+    } else {
+      /* Fix bug bug #21582: out of sequence ACK, didn't really ack anything */
+      pcb->acked = 0;
+    }
+
+    /* We go through the ->unsent list to see if any of the segments
+       on the list are acknowledged by the ACK. This may seem
+       strange since an "unsent" segment shouldn't be acked. The
+       rationale is that lwIP puts all outstanding segments on the
+       ->unsent list after a retransmission, so these segments may
+       in fact have been sent once. */
+    while (pcb->unsent != NULL &&
+           TCP_SEQ_BETWEEN(ackno, ntohl(pcb->unsent->tcphdr->seqno) + 
+                           TCP_TCPLEN(pcb->unsent), pcb->snd_nxt)) {
+      LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unsent\n",
+                                    ntohl(pcb->unsent->tcphdr->seqno), ntohl(pcb->unsent->tcphdr->seqno) +
+                                    TCP_TCPLEN(pcb->unsent)));
+
+      next = pcb->unsent;
+      pcb->unsent = pcb->unsent->next;
+      LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
+      LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
+      /* Prevent ACK for FIN to generate a sent event */
+      if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
+        pcb->acked--;
+      }
+      pcb->snd_queuelen -= pbuf_clen(next->p);
+      tcp_seg_free(next);
+      LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unsent)\n", (u16_t)pcb->snd_queuelen));
+      if (pcb->snd_queuelen != 0) {
+        LWIP_ASSERT("tcp_receive: valid queue length",
+          pcb->unacked != NULL || pcb->unsent != NULL);
+      }
+    }
+    /* End of ACK for new data processing. */
+
+    LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: pcb->rttest %"U32_F" rtseq %"U32_F" ackno %"U32_F"\n",
+                                pcb->rttest, pcb->rtseq, ackno));
+
+    /* RTT estimation calculations. This is done by checking if the
+       incoming segment acknowledges the segment we use to take a
+       round-trip time measurement. */
+    if (pcb->rttest && TCP_SEQ_LT(pcb->rtseq, ackno)) {
+      /* diff between this shouldn't exceed 32K since this are tcp timer ticks
+         and a round-trip shouldn't be that long... */
+      m = (s16_t)(tcp_ticks - pcb->rttest);
+
+      LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: experienced rtt %"U16_F" ticks (%"U16_F" msec).\n",
+                                  m, m * TCP_SLOW_INTERVAL));
+
+      /* This is taken directly from VJs original code in his paper */
+      m = m - (pcb->sa >> 3);
+      pcb->sa += m;
+      if (m < 0) {
+        m = -m;
+      }
+      m = m - (pcb->sv >> 2);
+      pcb->sv += m;
+      pcb->rto = (pcb->sa >> 3) + pcb->sv;
+
+      LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: RTO %"U16_F" (%"U16_F" milliseconds)\n",
+                                  pcb->rto, pcb->rto * TCP_SLOW_INTERVAL));
+
+      pcb->rttest = 0;
+    }
+  }
+
+  /* If the incoming segment contains data, we must process it
+     further. */
+  if (tcplen > 0) {
+    /* This code basically does three things:
+
+    +) If the incoming segment contains data that is the next
+    in-sequence data, this data is passed to the application. This
+    might involve trimming the first edge of the data. The rcv_nxt
+    variable and the advertised window are adjusted.
+
+    +) If the incoming segment has data that is above the next
+    sequence number expected (->rcv_nxt), the segment is placed on
+    the ->ooseq queue. This is done by finding the appropriate
+    place in the ->ooseq queue (which is ordered by sequence
+    number) and trim the segment in both ends if needed. An
+    immediate ACK is sent to indicate that we received an
+    out-of-sequence segment.
+
+    +) Finally, we check if the first segment on the ->ooseq queue
+    now is in sequence (i.e., if rcv_nxt >= ooseq->seqno). If
+    rcv_nxt > ooseq->seqno, we must trim the first edge of the
+    segment on ->ooseq before we adjust rcv_nxt. The data in the
+    segments that are now on sequence are chained onto the
+    incoming segment so that we only need to call the application
+    once.
+    */
+
+    /* First, we check if we must trim the first edge. We have to do
+       this if the sequence number of the incoming segment is less
+       than rcv_nxt, and the sequence number plus the length of the
+       segment is larger than rcv_nxt. */
+    /*    if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
+          if (TCP_SEQ_LT(pcb->rcv_nxt, seqno + tcplen)) {*/
+    if (TCP_SEQ_BETWEEN(pcb->rcv_nxt, seqno + 1, seqno + tcplen - 1)){
+      /* Trimming the first edge is done by pushing the payload
+         pointer in the pbuf downwards. This is somewhat tricky since
+         we do not want to discard the full contents of the pbuf up to
+         the new starting point of the data since we have to keep the
+         TCP header which is present in the first pbuf in the chain.
+
+         What is done is really quite a nasty hack: the first pbuf in
+         the pbuf chain is pointed to by inseg.p. Since we need to be
+         able to deallocate the whole pbuf, we cannot change this
+         inseg.p pointer to point to any of the later pbufs in the
+         chain. Instead, we point the ->payload pointer in the first
+         pbuf to data in one of the later pbufs. We also set the
+         inseg.data pointer to point to the right place. This way, the
+         ->p pointer will still point to the first pbuf, but the
+         ->p->payload pointer will point to data in another pbuf.
+
+         After we are done with adjusting the pbuf pointers we must
+         adjust the ->data pointer in the seg and the segment
+         length.*/
+
+      off = pcb->rcv_nxt - seqno;
+      p = inseg.p;
+      LWIP_ASSERT("inseg.p != NULL", inseg.p);
+      LWIP_ASSERT("insane offset!", (off < 0x7fff));
+      if (inseg.p->len < off) {
+        LWIP_ASSERT("pbuf too short!", (((s32_t)inseg.p->tot_len) >= off));
+        new_tot_len = (u16_t)(inseg.p->tot_len - off);
+        while (p->len < off) {
+          off -= p->len;
+          /* KJM following line changed (with addition of new_tot_len var)
+             to fix bug #9076
+             inseg.p->tot_len -= p->len; */
+          p->tot_len = new_tot_len;
+          p->len = 0;
+          p = p->next;
+        }
+        if(pbuf_header(p, (s16_t)-off)) {
+          /* Do we need to cope with this failing?  Assert for now */
+          LWIP_ASSERT("pbuf_header failed", 0);
+        }
+      } else {
+        if(pbuf_header(inseg.p, (s16_t)-off)) {
+          /* Do we need to cope with this failing?  Assert for now */
+          LWIP_ASSERT("pbuf_header failed", 0);
+        }
+      }
+      inseg.len -= (u16_t)(pcb->rcv_nxt - seqno);
+      inseg.tcphdr->seqno = seqno = pcb->rcv_nxt;
+    }
+    else {
+      if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
+        /* the whole segment is < rcv_nxt */
+        /* must be a duplicate of a packet that has already been correctly handled */
+
+        LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: duplicate seqno %"U32_F"\n", seqno));
+        tcp_ack_now(pcb);
+      }
+    }
+
+    /* The sequence number must be within the window (above rcv_nxt
+       and below rcv_nxt + rcv_wnd) in order to be further
+       processed. */
+    if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, 
+                        pcb->rcv_nxt + pcb->rcv_wnd - 1)){
+      if (pcb->rcv_nxt == seqno) {
+        /* The incoming segment is the next in sequence. We check if
+           we have to trim the end of the segment and update rcv_nxt
+           and pass the data to the application. */
+        tcplen = TCP_TCPLEN(&inseg);
+
+        if (tcplen > pcb->rcv_wnd) {
+          LWIP_DEBUGF(TCP_INPUT_DEBUG, 
+                      ("tcp_receive: other end overran receive window"
+                       "seqno %"U32_F" len %"U16_F" right edge %"U32_F"\n",
+                       seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd));
+          if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
+            /* Must remove the FIN from the header as we're trimming 
+             * that byte of sequence-space from the packet */
+            TCPH_FLAGS_SET(inseg.tcphdr, TCPH_FLAGS(inseg.tcphdr) &~ TCP_FIN);
+          }
+          /* Adjust length of segment to fit in the window. */
+          inseg.len = pcb->rcv_wnd;
+          if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
+            inseg.len -= 1;
+          }
+          pbuf_realloc(inseg.p, inseg.len);
+          tcplen = TCP_TCPLEN(&inseg);
+          LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n",
+                      (seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd));
+        }
+#if TCP_QUEUE_OOSEQ
+        /* Received in-sequence data, adjust ooseq data if:
+           - FIN has been received or
+           - inseq overlaps with ooseq */
+        if (pcb->ooseq != NULL) {
+          if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
+            LWIP_DEBUGF(TCP_INPUT_DEBUG, 
+                        ("tcp_receive: received in-order FIN, binning ooseq queue\n"));
+            /* Received in-order FIN means anything that was received
+             * out of order must now have been received in-order, so
+             * bin the ooseq queue */
+            while (pcb->ooseq != NULL) {
+              struct tcp_seg *old_ooseq = pcb->ooseq;
+              pcb->ooseq = pcb->ooseq->next;
+              tcp_seg_free(old_ooseq);
+            }
+          }
+          else {
+            next = pcb->ooseq;
+            /* Remove all segments on ooseq that are covered by inseg already.
+             * FIN is copied from ooseq to inseg if present. */
+            while (next &&
+                   TCP_SEQ_GEQ(seqno + tcplen,
+                               next->tcphdr->seqno + next->len)) {
+              /* inseg cannot have FIN here (already processed above) */
+              if (TCPH_FLAGS(next->tcphdr) & TCP_FIN &&
+                  (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) == 0) {
+                TCPH_SET_FLAG(inseg.tcphdr, TCP_FIN);
+                tcplen = TCP_TCPLEN(&inseg);
+              }
+              prev = next;
+              next = next->next;
+              tcp_seg_free(prev);
+            }
+            /* Now trim right side of inseg if it overlaps with the first
+             * segment on ooseq */
+            if (next &&
+                TCP_SEQ_GT(seqno + tcplen,
+                           next->tcphdr->seqno)) {
+              /* inseg cannot have FIN here (already processed above) */
+              inseg.len = (u16_t)(next->tcphdr->seqno - seqno);
+              if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
+                inseg.len -= 1;
+              }
+              pbuf_realloc(inseg.p, inseg.len);
+              tcplen = TCP_TCPLEN(&inseg);
+              LWIP_ASSERT("tcp_receive: segment not trimmed correctly to ooseq queue\n",
+                          (seqno + tcplen) == next->tcphdr->seqno);
+            }
+            pcb->ooseq = next;
+          }
+        }
+#endif /* TCP_QUEUE_OOSEQ */
+
+        pcb->rcv_nxt = seqno + tcplen;
+
+        /* Update the receiver's (our) window. */
+        LWIP_ASSERT("tcp_receive: tcplen > rcv_wnd\n", pcb->rcv_wnd >= tcplen);
+        pcb->rcv_wnd -= tcplen;
+
+        tcp_update_rcv_ann_wnd(pcb);
+
+        /* If there is data in the segment, we make preparations to
+           pass this up to the application. The ->recv_data variable
+           is used for holding the pbuf that goes to the
+           application. The code for reassembling out-of-sequence data
+           chains its data on this pbuf as well.
+
+           If the segment was a FIN, we set the TF_GOT_FIN flag that will
+           be used to indicate to the application that the remote side has
+           closed its end of the connection. */
+        if (inseg.p->tot_len > 0) {
+          recv_data = inseg.p;
+          /* Since this pbuf now is the responsibility of the
+             application, we delete our reference to it so that we won't
+             (mistakingly) deallocate it. */
+          inseg.p = NULL;
+        }
+        if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
+          LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: received FIN.\n"));
+          recv_flags |= TF_GOT_FIN;
+        }
+
+#if TCP_QUEUE_OOSEQ
+        /* We now check if we have segments on the ->ooseq queue that
+           are now in sequence. */
+        while (pcb->ooseq != NULL &&
+               pcb->ooseq->tcphdr->seqno == pcb->rcv_nxt) {
+
+          cseg = pcb->ooseq;
+          seqno = pcb->ooseq->tcphdr->seqno;
+
+          pcb->rcv_nxt += TCP_TCPLEN(cseg);
+          LWIP_ASSERT("tcp_receive: ooseq tcplen > rcv_wnd\n",
+                      pcb->rcv_wnd >= TCP_TCPLEN(cseg));
+          pcb->rcv_wnd -= TCP_TCPLEN(cseg);
+
+          tcp_update_rcv_ann_wnd(pcb);
+
+          if (cseg->p->tot_len > 0) {
+            /* Chain this pbuf onto the pbuf that we will pass to
+               the application. */
+            if (recv_data) {
+              pbuf_cat(recv_data, cseg->p);
+            } else {
+              recv_data = cseg->p;
+            }
+            cseg->p = NULL;
+          }
+          if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
+            LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: dequeued FIN.\n"));
+            recv_flags |= TF_GOT_FIN;
+            if (pcb->state == ESTABLISHED) { /* force passive close or we can move to active close */
+              pcb->state = CLOSE_WAIT;
+            } 
+          }
+
+          pcb->ooseq = cseg->next;
+          tcp_seg_free(cseg);
+        }
+#endif /* TCP_QUEUE_OOSEQ */
+
+
+        /* Acknowledge the segment(s). */
+        tcp_ack(pcb);
+
+      } else {
+        /* We get here if the incoming segment is out-of-sequence. */
+        tcp_send_empty_ack(pcb);
+#if TCP_QUEUE_OOSEQ
+        /* We queue the segment on the ->ooseq queue. */
+        if (pcb->ooseq == NULL) {
+          pcb->ooseq = tcp_seg_copy(&inseg);
+        } else {
+          /* If the queue is not empty, we walk through the queue and
+             try to find a place where the sequence number of the
+             incoming segment is between the sequence numbers of the
+             previous and the next segment on the ->ooseq queue. That is
+             the place where we put the incoming segment. If needed, we
+             trim the second edges of the previous and the incoming
+             segment so that it will fit into the sequence.
+
+             If the incoming segment has the same sequence number as a
+             segment on the ->ooseq queue, we discard the segment that
+             contains less data. */
+
+          prev = NULL;
+          for(next = pcb->ooseq; next != NULL; next = next->next) {
+            if (seqno == next->tcphdr->seqno) {
+              /* The sequence number of the incoming segment is the
+                 same as the sequence number of the segment on
+                 ->ooseq. We check the lengths to see which one to
+                 discard. */
+              if (inseg.len > next->len) {
+                /* The incoming segment is larger than the old
+                   segment. We replace some segments with the new
+                   one. */
+                cseg = tcp_seg_copy(&inseg);
+                if (cseg != NULL) {
+                  if (prev != NULL) {
+                    prev->next = cseg;
+                  } else {
+                    pcb->ooseq = cseg;
+                  }
+                  tcp_oos_insert_segment(cseg, next);
+                }
+                break;
+              } else {
+                /* Either the lenghts are the same or the incoming
+                   segment was smaller than the old one; in either
+                   case, we ditch the incoming segment. */
+                break;
+              }
+            } else {
+              if (prev == NULL) {
+                if (TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {
+                  /* The sequence number of the incoming segment is lower
+                     than the sequence number of the first segment on the
+                     queue. We put the incoming segment first on the
+                     queue. */
+                  cseg = tcp_seg_copy(&inseg);
+                  if (cseg != NULL) {
+                    pcb->ooseq = cseg;
+                    tcp_oos_insert_segment(cseg, next);
+                  }
+                  break;
+                }
+              } else {
+                /*if (TCP_SEQ_LT(prev->tcphdr->seqno, seqno) &&
+                  TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {*/
+                if (TCP_SEQ_BETWEEN(seqno, prev->tcphdr->seqno+1, next->tcphdr->seqno-1)) {
+                  /* The sequence number of the incoming segment is in
+                     between the sequence numbers of the previous and
+                     the next segment on ->ooseq. We trim trim the previous
+                     segment, delete next segments that included in received segment
+                     and trim received, if needed. */
+                  cseg = tcp_seg_copy(&inseg);
+                  if (cseg != NULL) {
+                    if (TCP_SEQ_GT(prev->tcphdr->seqno + prev->len, seqno)) {
+                      /* We need to trim the prev segment. */
+                      prev->len = (u16_t)(seqno - prev->tcphdr->seqno);
+                      pbuf_realloc(prev->p, prev->len);
+                    }
+                    prev->next = cseg;
+                    tcp_oos_insert_segment(cseg, next);
+                  }
+                  break;
+                }
+              }
+              /* If the "next" segment is the last segment on the
+                 ooseq queue, we add the incoming segment to the end
+                 of the list. */
+              if (next->next == NULL &&
+                  TCP_SEQ_GT(seqno, next->tcphdr->seqno)) {
+                if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) {
+                  /* segment "next" already contains all data */
+                  break;
+                }
+                next->next = tcp_seg_copy(&inseg);
+                if (next->next != NULL) {
+                  if (TCP_SEQ_GT(next->tcphdr->seqno + next->len, seqno)) {
+                    /* We need to trim the last segment. */
+                    next->len = (u16_t)(seqno - next->tcphdr->seqno);
+                    pbuf_realloc(next->p, next->len);
+                  }
+                  /* check if the remote side overruns our receive window */
+                  if ((u32_t)tcplen + seqno > pcb->rcv_nxt + (u32_t)pcb->rcv_wnd) {
+                    LWIP_DEBUGF(TCP_INPUT_DEBUG, 
+                                ("tcp_receive: other end overran receive window"
+                                 "seqno %"U32_F" len %"U16_F" right edge %"U32_F"\n",
+                                 seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd));
+                    if (TCPH_FLAGS(next->next->tcphdr) & TCP_FIN) {
+                      /* Must remove the FIN from the header as we're trimming 
+                       * that byte of sequence-space from the packet */
+                      TCPH_FLAGS_SET(next->next->tcphdr, TCPH_FLAGS(next->next->tcphdr) &~ TCP_FIN);
+                    }
+                    /* Adjust length of segment to fit in the window. */
+                    next->next->len = pcb->rcv_nxt + pcb->rcv_wnd - seqno;
+                    pbuf_realloc(next->next->p, next->next->len);
+                    tcplen = TCP_TCPLEN(next->next);
+                    LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n",
+                                (seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd));
+                  }
+                }
+                break;
+              }
+            }
+            prev = next;
+          }
+        }
+#endif /* TCP_QUEUE_OOSEQ */
+
+      }
+    } else {
+      /* The incoming segment is not withing the window. */
+      tcp_send_empty_ack(pcb);
+    }
+  } else {
+    /* Segments with length 0 is taken care of here. Segments that
+       fall out of the window are ACKed. */
+    /*if (TCP_SEQ_GT(pcb->rcv_nxt, seqno) ||
+      TCP_SEQ_GEQ(seqno, pcb->rcv_nxt + pcb->rcv_wnd)) {*/
+    if(!TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt + pcb->rcv_wnd-1)){
+      tcp_ack_now(pcb);
+    }
+  }
+}
+
+/**
+ * Parses the options contained in the incoming segment. 
+ *
+ * Called from tcp_listen_input() and tcp_process().
+ * Currently, only the MSS option is supported!
+ *
+ * @param pcb the tcp_pcb for which a segment arrived
+ */
+static void
+tcp_parseopt(struct tcp_pcb *pcb)
+{
+  u16_t c, max_c;
+  u16_t mss;
+  u8_t *opts, opt;
+#if LWIP_TCP_TIMESTAMPS
+  u32_t tsval;
+#endif
+
+  opts = (u8_t *)tcphdr + TCP_HLEN;
+
+  /* Parse the TCP MSS option, if present. */
+  if(TCPH_HDRLEN(tcphdr) > 0x5) {
+    max_c = (TCPH_HDRLEN(tcphdr) - 5) << 2;
+    for (c = 0; c < max_c; ) {
+      opt = opts[c];
+      switch (opt) {
+      case 0x00:
+        /* End of options. */
+        LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: EOL\n"));
+        return;
+      case 0x01:
+        /* NOP option. */
+        ++c;
+        LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: NOP\n"));
+        break;
+      case 0x02:
+        LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: MSS\n"));
+        if (opts[c + 1] != 0x04 || c + 0x04 > max_c) {
+          /* Bad length */
+          LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
+          return;
+        }
+        /* An MSS option with the right option length. */
+        mss = (opts[c + 2] << 8) | opts[c + 3];
+        /* Limit the mss to the configured TCP_MSS and prevent division by zero */
+        pcb->mss = ((mss > TCP_MSS) || (mss == 0)) ? TCP_MSS : mss;
+        /* Advance to next option */
+        c += 0x04;
+        break;
+#if LWIP_TCP_TIMESTAMPS
+      case 0x08:
+        LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: TS\n"));
+        if (opts[c + 1] != 0x0A || c + 0x0A > max_c) {
+          /* Bad length */
+          LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
+          return;
+        }
+        /* TCP timestamp option with valid length */
+        tsval = (opts[c+2]) | (opts[c+3] << 8) | 
+          (opts[c+4] << 16) | (opts[c+5] << 24);
+        if (flags & TCP_SYN) {
+          pcb->ts_recent = ntohl(tsval);
+          pcb->flags |= TF_TIMESTAMP;
+        } else if (TCP_SEQ_BETWEEN(pcb->ts_lastacksent, seqno, seqno+tcplen)) {
+          pcb->ts_recent = ntohl(tsval);
+        }
+        /* Advance to next option */
+        c += 0x0A;
+        break;
+#endif
+      default:
+        LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: other\n"));
+        if (opts[c + 1] == 0) {
+          LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
+          /* If the length field is zero, the options are malformed
+             and we don't process them further. */
+          return;
+        }
+        /* All other options have a length field, so that we easily
+           can skip past them. */
+        c += opts[c + 1];
+      }
+    }
+  }
+}
+
+#endif /* LWIP_TCP */
diff --git a/core/lwip/src/core/tcp_out.c b/core/lwip/src/core/tcp_out.c
new file mode 100644
index 00000000..86e09195
--- /dev/null
+++ b/core/lwip/src/core/tcp_out.c
@@ -0,0 +1,1468 @@
+/**
+ * @file
+ * Transmission Control Protocol, outgoing traffic
+ *
+ * The output functions of TCP.
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/tcp_impl.h"
+#include "lwip/def.h"
+#include "lwip/mem.h"
+#include "lwip/memp.h"
+#include "lwip/sys.h"
+#include "lwip/ip_addr.h"
+#include "lwip/netif.h"
+#include "lwip/inet_chksum.h"
+#include "lwip/stats.h"
+#include "lwip/snmp.h"
+
+#include <string.h>
+
+/* Define some copy-macros for checksum-on-copy so that the code looks
+   nicer by preventing too many ifdef's. */
+#if TCP_CHECKSUM_ON_COPY
+#define TCP_DATA_COPY(dst, src, len, seg) do { \
+  tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), \
+                     len, &seg->chksum, &seg->chksum_swapped); \
+  seg->flags |= TF_SEG_DATA_CHECKSUMMED; } while(0)
+#define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped)  \
+  tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), len, chksum, chksum_swapped);
+#else /* TCP_CHECKSUM_ON_COPY*/
+#define TCP_DATA_COPY(dst, src, len, seg)                     MEMCPY(dst, src, len)
+#define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) MEMCPY(dst, src, len)
+#endif /* TCP_CHECKSUM_ON_COPY*/
+
+/** Define this to 1 for an extra check that the output checksum is valid
+ * (usefule when the checksum is generated by the application, not the stack) */
+#ifndef TCP_CHECKSUM_ON_COPY_SANITY_CHECK
+#define TCP_CHECKSUM_ON_COPY_SANITY_CHECK   0
+#endif
+
+/* Forward declarations.*/
+static void tcp_output_segment(struct tcp_seg *seg, struct tcp_pcb *pcb);
+
+/** Allocate a pbuf and create a tcphdr at p->payload, used for output
+ * functions other than the default tcp_output -> tcp_output_segment
+ * (e.g. tcp_send_empty_ack, etc.)
+ *
+ * @param pcb tcp pcb for which to send a packet (used to initialize tcp_hdr)
+ * @param optlen length of header-options
+ * @param datalen length of tcp data to reserve in pbuf
+ * @param seqno_be seqno in network byte order (big-endian)
+ * @return pbuf with p->payload being the tcp_hdr
+ */
+static struct pbuf *
+tcp_output_alloc_header(struct tcp_pcb *pcb, u16_t optlen, u16_t datalen,
+                      u32_t seqno_be /* already in network byte order */)
+{
+  struct tcp_hdr *tcphdr;
+  struct pbuf *p = pbuf_alloc(PBUF_IP, TCP_HLEN + optlen + datalen, PBUF_RAM);
+  if (p != NULL) {
+    LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
+                 (p->len >= TCP_HLEN + optlen));
+    tcphdr = (struct tcp_hdr *)p->payload;
+    tcphdr->src = htons(pcb->local_port);
+    tcphdr->dest = htons(pcb->remote_port);
+    tcphdr->seqno = seqno_be;
+    tcphdr->ackno = htonl(pcb->rcv_nxt);
+    TCPH_HDRLEN_FLAGS_SET(tcphdr, (5 + optlen / 4), TCP_ACK);
+    tcphdr->wnd = htons(pcb->rcv_ann_wnd);
+    tcphdr->chksum = 0;
+    tcphdr->urgp = 0;
+
+    /* If we're sending a packet, update the announced right window edge */
+    pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
+  }
+  return p;
+}
+
+/**
+ * Called by tcp_close() to send a segment including FIN flag but not data.
+ *
+ * @param pcb the tcp_pcb over which to send a segment
+ * @return ERR_OK if sent, another err_t otherwise
+ */
+err_t
+tcp_send_fin(struct tcp_pcb *pcb)
+{
+  /* first, try to add the fin to the last unsent segment */
+  if (pcb->unsent != NULL) {
+    struct tcp_seg *last_unsent;
+    for (last_unsent = pcb->unsent; last_unsent->next != NULL;
+         last_unsent = last_unsent->next);
+
+    if ((TCPH_FLAGS(last_unsent->tcphdr) & (TCP_SYN | TCP_FIN | TCP_RST)) == 0) {
+      /* no SYN/FIN/RST flag in the header, we can add the FIN flag */
+      TCPH_SET_FLAG(last_unsent->tcphdr, TCP_FIN);
+      return ERR_OK;
+    }
+  }
+  /* no data, no length, flags, copy=1, no optdata */
+  return tcp_enqueue_flags(pcb, TCP_FIN);
+}
+
+/**
+ * Create a TCP segment with prefilled header.
+ *
+ * Called by tcp_write and tcp_enqueue_flags.
+ *
+ * @param pcb Protocol control block for the TCP connection.
+ * @param p pbuf that is used to hold the TCP header.
+ * @param flags TCP flags for header.
+ * @param seqno TCP sequence number of this packet
+ * @param optflags options to include in TCP header
+ * @return a new tcp_seg pointing to p, or NULL.
+ * The TCP header is filled in except ackno and wnd.
+ * p is freed on failure.
+ */
+static struct tcp_seg *
+tcp_create_segment(struct tcp_pcb *pcb, struct pbuf *p, u8_t flags, u32_t seqno, u8_t optflags)
+{
+  struct tcp_seg *seg;
+  u8_t optlen = LWIP_TCP_OPT_LENGTH(optflags);
+
+  if ((seg = (struct tcp_seg *)memp_malloc(MEMP_TCP_SEG)) == NULL) {
+    LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_create_segment: no memory.\n"));
+    pbuf_free(p);
+    return NULL;
+  }
+  seg->flags = optflags;
+  seg->next = NULL;
+  seg->p = p;
+  seg->len = p->tot_len - optlen;
+#if TCP_OVERSIZE_DBGCHECK
+  seg->oversize_left = 0;
+#endif /* TCP_OVERSIZE_DBGCHECK */
+#if TCP_CHECKSUM_ON_COPY
+  seg->chksum = 0;
+  seg->chksum_swapped = 0;
+  /* check optflags */
+  LWIP_ASSERT("invalid optflags passed: TF_SEG_DATA_CHECKSUMMED",
+              (optflags & TF_SEG_DATA_CHECKSUMMED) == 0);
+#endif /* TCP_CHECKSUM_ON_COPY */
+
+  /* build TCP header */
+  if (pbuf_header(p, TCP_HLEN)) {
+    LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_create_segment: no room for TCP header in pbuf.\n"));
+    TCP_STATS_INC(tcp.err);
+    tcp_seg_free(seg);
+    return NULL;
+  }
+  seg->tcphdr = (struct tcp_hdr *)seg->p->payload;
+  seg->tcphdr->src = htons(pcb->local_port);
+  seg->tcphdr->dest = htons(pcb->remote_port);
+  seg->tcphdr->seqno = htonl(seqno);
+  /* ackno is set in tcp_output */
+  TCPH_HDRLEN_FLAGS_SET(seg->tcphdr, (5 + optlen / 4), flags);
+  /* wnd and chksum are set in tcp_output */
+  seg->tcphdr->urgp = 0;
+  return seg;
+} 
+
+/**
+ * Allocate a PBUF_RAM pbuf, perhaps with extra space at the end.
+ *
+ * This function is like pbuf_alloc(layer, length, PBUF_RAM) except
+ * there may be extra bytes available at the end.
+ *
+ * @param layer flag to define header size.
+ * @param length size of the pbuf's payload.
+ * @param max_length maximum usable size of payload+oversize.
+ * @param oversize pointer to a u16_t that will receive the number of usable tail bytes.
+ * @param pcb The TCP connection that willo enqueue the pbuf.
+ * @param apiflags API flags given to tcp_write.
+ * @param first_seg true when this pbuf will be used in the first enqueued segment.
+ * @param 
+ */
+#if TCP_OVERSIZE
+static struct pbuf *
+tcp_pbuf_prealloc(pbuf_layer layer, u16_t length, u16_t max_length,
+                  u16_t *oversize, struct tcp_pcb *pcb, u8_t apiflags,
+                  u8_t first_seg)
+{
+  struct pbuf *p;
+  u16_t alloc = length;
+
+#if LWIP_NETIF_TX_SINGLE_PBUF
+  LWIP_UNUSED_ARG(max_length);
+  LWIP_UNUSED_ARG(pcb);
+  LWIP_UNUSED_ARG(apiflags);
+  LWIP_UNUSED_ARG(first_seg);
+  /* always create MSS-sized pbufs */
+  alloc = TCP_MSS;
+#else /* LWIP_NETIF_TX_SINGLE_PBUF */
+  if (length < max_length) {
+    /* Should we allocate an oversized pbuf, or just the minimum
+     * length required? If tcp_write is going to be called again
+     * before this segment is transmitted, we want the oversized
+     * buffer. If the segment will be transmitted immediately, we can
+     * save memory by allocating only length. We use a simple
+     * heuristic based on the following information:
+     *
+     * Did the user set TCP_WRITE_FLAG_MORE?
+     *
+     * Will the Nagle algorithm defer transmission of this segment?
+     */
+    if ((apiflags & TCP_WRITE_FLAG_MORE) ||
+        (!(pcb->flags & TF_NODELAY) &&
+         (!first_seg ||
+          pcb->unsent != NULL ||
+          pcb->unacked != NULL))) {
+      alloc = LWIP_MIN(max_length, LWIP_MEM_ALIGN_SIZE(length + TCP_OVERSIZE));
+    }
+  }
+#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
+  p = pbuf_alloc(layer, alloc, PBUF_RAM);
+  if (p == NULL) {
+    return NULL;
+  }
+  LWIP_ASSERT("need unchained pbuf", p->next == NULL);
+  *oversize = p->len - length;
+  /* trim p->len to the currently used size */
+  p->len = p->tot_len = length;
+  return p;
+}
+#else /* TCP_OVERSIZE */
+#define tcp_pbuf_prealloc(layer, length, mx, os, pcb, api, fst) pbuf_alloc((layer), (length), PBUF_RAM)
+#endif /* TCP_OVERSIZE */
+
+#if TCP_CHECKSUM_ON_COPY
+/** Add a checksum of newly added data to the segment */
+static void
+tcp_seg_add_chksum(u16_t chksum, u16_t len, u16_t *seg_chksum,
+                   u8_t *seg_chksum_swapped)
+{
+  u32_t helper;
+  /* add chksum to old chksum and fold to u16_t */
+  helper = chksum + *seg_chksum;
+  chksum = FOLD_U32T(helper);
+  if ((len & 1) != 0) {
+    *seg_chksum_swapped = 1 - *seg_chksum_swapped;
+    chksum = SWAP_BYTES_IN_WORD(chksum);
+  }
+  *seg_chksum = chksum;
+}
+#endif /* TCP_CHECKSUM_ON_COPY */
+
+/** Checks if tcp_write is allowed or not (checks state, snd_buf and snd_queuelen).
+ *
+ * @param pcb the tcp pcb to check for
+ * @param len length of data to send (checked agains snd_buf)
+ * @return ERR_OK if tcp_write is allowed to proceed, another err_t otherwise
+ */
+static err_t
+tcp_write_checks(struct tcp_pcb *pcb, u16_t len)
+{
+  /* connection is in invalid state for data transmission? */
+  if ((pcb->state != ESTABLISHED) &&
+      (pcb->state != CLOSE_WAIT) &&
+      (pcb->state != SYN_SENT) &&
+      (pcb->state != SYN_RCVD)) {
+    LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_STATE | LWIP_DBG_LEVEL_SEVERE, ("tcp_write() called in invalid state\n"));
+    return ERR_CONN;
+  } else if (len == 0) {
+    return ERR_OK;
+  }
+
+  /* fail on too much data */
+  if (len > pcb->snd_buf) {
+    LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_write: too much data (len=%"U16_F" > snd_buf=%"U16_F")\n",
+      len, pcb->snd_buf));
+    pcb->flags |= TF_NAGLEMEMERR;
+    return ERR_MEM;
+  }
+
+  LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
+
+  /* If total number of pbufs on the unsent/unacked queues exceeds the
+   * configured maximum, return an error */
+  /* check for configured max queuelen and possible overflow */
+  if ((pcb->snd_queuelen >= TCP_SND_QUEUELEN) || (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
+    LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_write: too long queue %"U16_F" (max %"U16_F")\n",
+      pcb->snd_queuelen, TCP_SND_QUEUELEN));
+    TCP_STATS_INC(tcp.memerr);
+    pcb->flags |= TF_NAGLEMEMERR;
+    return ERR_MEM;
+  }
+  if (pcb->snd_queuelen != 0) {
+    LWIP_ASSERT("tcp_write: pbufs on queue => at least one queue non-empty",
+      pcb->unacked != NULL || pcb->unsent != NULL);
+  } else {
+    LWIP_ASSERT("tcp_write: no pbufs on queue => both queues empty",
+      pcb->unacked == NULL && pcb->unsent == NULL);
+  }
+  return ERR_OK;
+}
+
+/**
+ * Write data for sending (but does not send it immediately).
+ *
+ * It waits in the expectation of more data being sent soon (as
+ * it can send them more efficiently by combining them together).
+ * To prompt the system to send data now, call tcp_output() after
+ * calling tcp_write().
+ *
+ * @param pcb Protocol control block for the TCP connection to enqueue data for.
+ * @param arg Pointer to the data to be enqueued for sending.
+ * @param len Data length in bytes
+ * @param apiflags combination of following flags :
+ * - TCP_WRITE_FLAG_COPY (0x01) data will be copied into memory belonging to the stack
+ * - TCP_WRITE_FLAG_MORE (0x02) for TCP connection, PSH flag will be set on last segment sent,
+ * @return ERR_OK if enqueued, another err_t on error
+ */
+err_t
+tcp_write(struct tcp_pcb *pcb, const void *arg, u16_t len, u8_t apiflags)
+{
+  struct pbuf *concat_p = NULL;
+  struct tcp_seg *last_unsent = NULL, *seg = NULL, *prev_seg = NULL, *queue = NULL;
+  u16_t pos = 0; /* position in 'arg' data */
+  u16_t queuelen;
+  u8_t optlen = 0;
+  u8_t optflags = 0;
+#if TCP_OVERSIZE
+  u16_t oversize = 0;
+  u16_t oversize_used = 0;
+#endif /* TCP_OVERSIZE */
+#if TCP_CHECKSUM_ON_COPY
+  u16_t concat_chksum = 0;
+  u8_t concat_chksum_swapped = 0;
+  u16_t concat_chksummed = 0;
+#endif /* TCP_CHECKSUM_ON_COPY */
+  err_t err;
+
+#if LWIP_NETIF_TX_SINGLE_PBUF
+  /* Always copy to try to create single pbufs for TX */
+  apiflags |= TCP_WRITE_FLAG_COPY;
+#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
+
+  LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_write(pcb=%p, data=%p, len=%"U16_F", apiflags=%"U16_F")\n",
+    (void *)pcb, arg, len, (u16_t)apiflags));
+  LWIP_ERROR("tcp_write: arg == NULL (programmer violates API)", 
+             arg != NULL, return ERR_ARG;);
+
+  err = tcp_write_checks(pcb, len);
+  if (err != ERR_OK) {
+    return err;
+  }
+  queuelen = pcb->snd_queuelen;
+
+#if LWIP_TCP_TIMESTAMPS
+  if ((pcb->flags & TF_TIMESTAMP)) {
+    optflags = TF_SEG_OPTS_TS;
+    optlen = LWIP_TCP_OPT_LENGTH(TF_SEG_OPTS_TS);
+  }
+#endif /* LWIP_TCP_TIMESTAMPS */
+
+
+  /*
+   * TCP segmentation is done in three phases with increasing complexity:
+   *
+   * 1. Copy data directly into an oversized pbuf.
+   * 2. Chain a new pbuf to the end of pcb->unsent.
+   * 3. Create new segments.
+   *
+   * We may run out of memory at any point. In that case we must
+   * return ERR_MEM and not change anything in pcb. Therefore, all
+   * changes are recorded in local variables and committed at the end
+   * of the function. Some pcb fields are maintained in local copies:
+   *
+   * queuelen = pcb->snd_queuelen
+   * oversize = pcb->unsent_oversize
+   *
+   * These variables are set consistently by the phases:
+   *
+   * seg points to the last segment tampered with.
+   *
+   * pos records progress as data is segmented.
+   */
+
+  /* Find the tail of the unsent queue. */
+  if (pcb->unsent != NULL) {
+    u16_t space;
+    u16_t unsent_optlen;
+
+    /* @todo: this could be sped up by keeping last_unsent in the pcb */
+    for (last_unsent = pcb->unsent; last_unsent->next != NULL;
+         last_unsent = last_unsent->next);
+
+    /* Usable space at the end of the last unsent segment */
+    unsent_optlen = LWIP_TCP_OPT_LENGTH(last_unsent->flags);
+    space = pcb->mss - (last_unsent->len + unsent_optlen);
+
+    /*
+     * Phase 1: Copy data directly into an oversized pbuf.
+     *
+     * The number of bytes copied is recorded in the oversize_used
+     * variable. The actual copying is done at the bottom of the
+     * function.
+     */
+#if TCP_OVERSIZE
+#if TCP_OVERSIZE_DBGCHECK
+    /* check that pcb->unsent_oversize matches last_unsent->unsent_oversize */
+    LWIP_ASSERT("unsent_oversize mismatch (pcb vs. last_unsent)",
+                pcb->unsent_oversize == last_unsent->oversize_left);
+#endif /* TCP_OVERSIZE_DBGCHECK */
+    oversize = pcb->unsent_oversize;
+    if (oversize > 0) {
+      LWIP_ASSERT("inconsistent oversize vs. space", oversize_used <= space);
+      seg = last_unsent;
+      oversize_used = oversize < len ? oversize : len;
+      pos += oversize_used;
+      oversize -= oversize_used;
+      space -= oversize_used;
+    }
+    /* now we are either finished or oversize is zero */
+    LWIP_ASSERT("inconsistend oversize vs. len", (oversize == 0) || (pos == len));
+#endif /* TCP_OVERSIZE */
+
+    /*
+     * Phase 2: Chain a new pbuf to the end of pcb->unsent.
+     *
+     * We don't extend segments containing SYN/FIN flags or options
+     * (len==0). The new pbuf is kept in concat_p and pbuf_cat'ed at
+     * the end.
+     */
+    if ((pos < len) && (space > 0) && (last_unsent->len > 0)) {
+      u16_t seglen = space < len - pos ? space : len - pos;
+      seg = last_unsent;
+
+      /* Create a pbuf with a copy or reference to seglen bytes. We
+       * can use PBUF_RAW here since the data appears in the middle of
+       * a segment. A header will never be prepended. */
+      if (apiflags & TCP_WRITE_FLAG_COPY) {
+        /* Data is copied */
+        if ((concat_p = tcp_pbuf_prealloc(PBUF_RAW, seglen, space, &oversize, pcb, apiflags, 1)) == NULL) {
+          LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2,
+                      ("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n",
+                       seglen));
+          goto memerr;
+        }
+#if TCP_OVERSIZE_DBGCHECK
+        last_unsent->oversize_left = oversize;
+#endif /* TCP_OVERSIZE_DBGCHECK */
+        TCP_DATA_COPY2(concat_p->payload, (u8_t*)arg + pos, seglen, &concat_chksum, &concat_chksum_swapped);
+#if TCP_CHECKSUM_ON_COPY
+        concat_chksummed += seglen;
+#endif /* TCP_CHECKSUM_ON_COPY */
+      } else {
+        /* Data is not copied */
+        if ((concat_p = pbuf_alloc(PBUF_RAW, seglen, PBUF_ROM)) == NULL) {
+          LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2,
+                      ("tcp_write: could not allocate memory for zero-copy pbuf\n"));
+          goto memerr;
+        }
+#if TCP_CHECKSUM_ON_COPY
+        /* calculate the checksum of nocopy-data */
+        tcp_seg_add_chksum(~inet_chksum((u8_t*)arg + pos, seglen), seglen,
+          &concat_chksum, &concat_chksum_swapped);
+        concat_chksummed += seglen;
+#endif /* TCP_CHECKSUM_ON_COPY */
+        /* reference the non-volatile payload data */
+        concat_p->payload = (u8_t*)arg + pos;
+      }
+
+      pos += seglen;
+      queuelen += pbuf_clen(concat_p);
+    }
+  } else {
+#if TCP_OVERSIZE
+    LWIP_ASSERT("unsent_oversize mismatch (pcb->unsent is NULL)",
+                pcb->unsent_oversize == 0);
+#endif /* TCP_OVERSIZE */
+  }
+
+  /*
+   * Phase 3: Create new segments.
+   *
+   * The new segments are chained together in the local 'queue'
+   * variable, ready to be appended to pcb->unsent.
+   */
+  while (pos < len) {
+    struct pbuf *p;
+    u16_t left = len - pos;
+    u16_t max_len = pcb->mss - optlen;
+    u16_t seglen = left > max_len ? max_len : left;
+#if TCP_CHECKSUM_ON_COPY
+    u16_t chksum = 0;
+    u8_t chksum_swapped = 0;
+#endif /* TCP_CHECKSUM_ON_COPY */
+
+    if (apiflags & TCP_WRITE_FLAG_COPY) {
+      /* If copy is set, memory should be allocated and data copied
+       * into pbuf */
+      if ((p = tcp_pbuf_prealloc(PBUF_TRANSPORT, seglen + optlen, pcb->mss, &oversize, pcb, apiflags, queue == NULL)) == NULL) {
+        LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n", seglen));
+        goto memerr;
+      }
+      LWIP_ASSERT("tcp_write: check that first pbuf can hold the complete seglen",
+                  (p->len >= seglen));
+      TCP_DATA_COPY2((char *)p->payload + optlen, (u8_t*)arg + pos, seglen, &chksum, &chksum_swapped);
+    } else {
+      /* Copy is not set: First allocate a pbuf for holding the data.
+       * Since the referenced data is available at least until it is
+       * sent out on the link (as it has to be ACKed by the remote
+       * party) we can safely use PBUF_ROM instead of PBUF_REF here.
+       */
+      struct pbuf *p2;
+#if TCP_OVERSIZE
+      LWIP_ASSERT("oversize == 0", oversize == 0);
+#endif /* TCP_OVERSIZE */
+      if ((p2 = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_ROM)) == NULL) {
+        LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write: could not allocate memory for zero-copy pbuf\n"));
+        goto memerr;
+      }
+#if TCP_CHECKSUM_ON_COPY
+      /* calculate the checksum of nocopy-data */
+      chksum = ~inet_chksum((u8_t*)arg + pos, seglen);
+#endif /* TCP_CHECKSUM_ON_COPY */
+      /* reference the non-volatile payload data */
+      p2->payload = (u8_t*)arg + pos;
+
+      /* Second, allocate a pbuf for the headers. */
+      if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
+        /* If allocation fails, we have to deallocate the data pbuf as
+         * well. */
+        pbuf_free(p2);
+        LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write: could not allocate memory for header pbuf\n"));
+        goto memerr;
+      }
+      /* Concatenate the headers and data pbufs together. */
+      pbuf_cat(p/*header*/, p2/*data*/);
+    }
+
+    queuelen += pbuf_clen(p);
+
+    /* Now that there are more segments queued, we check again if the
+     * length of the queue exceeds the configured maximum or
+     * overflows. */
+    if ((queuelen > TCP_SND_QUEUELEN) || (queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
+      LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 2, ("tcp_write: queue too long %"U16_F" (%"U16_F")\n", queuelen, TCP_SND_QUEUELEN));
+      pbuf_free(p);
+      goto memerr;
+    }
+
+    if ((seg = tcp_create_segment(pcb, p, 0, pcb->snd_lbb + pos, optflags)) == NULL) {
+      goto memerr;
+    }
+#if TCP_OVERSIZE_DBGCHECK
+    seg->oversize_left = oversize;
+#endif /* TCP_OVERSIZE_DBGCHECK */
+#if TCP_CHECKSUM_ON_COPY
+    seg->chksum = chksum;
+    seg->chksum_swapped = chksum_swapped;
+    seg->flags |= TF_SEG_DATA_CHECKSUMMED;
+#endif /* TCP_CHECKSUM_ON_COPY */
+
+    /* first segment of to-be-queued data? */
+    if (queue == NULL) {
+      queue = seg;
+    } else {
+      /* Attach the segment to the end of the queued segments */
+      LWIP_ASSERT("prev_seg != NULL", prev_seg != NULL);
+      prev_seg->next = seg;
+    }
+    /* remember last segment of to-be-queued data for next iteration */
+    prev_seg = seg;
+
+    LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_TRACE, ("tcp_write: queueing %"U32_F":%"U32_F"\n",
+      ntohl(seg->tcphdr->seqno),
+      ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg)));
+
+    pos += seglen;
+  }
+
+  /*
+   * All three segmentation phases were successful. We can commit the
+   * transaction.
+   */
+
+  /*
+   * Phase 1: If data has been added to the preallocated tail of
+   * last_unsent, we update the length fields of the pbuf chain.
+   */
+#if TCP_OVERSIZE
+  if (oversize_used > 0) {
+    struct pbuf *p;
+    /* Bump tot_len of whole chain, len of tail */
+    for (p = last_unsent->p; p; p = p->next) {
+      p->tot_len += oversize_used;
+      if (p->next == NULL) {
+        TCP_DATA_COPY((char *)p->payload + p->len, arg, oversize_used, last_unsent);
+        p->len += oversize_used;
+      }
+    }
+    last_unsent->len += oversize_used;
+#if TCP_OVERSIZE_DBGCHECK
+    last_unsent->oversize_left -= oversize_used;
+#endif /* TCP_OVERSIZE_DBGCHECK */
+  }
+  pcb->unsent_oversize = oversize;
+#endif /* TCP_OVERSIZE */
+
+  /*
+   * Phase 2: concat_p can be concatenated onto last_unsent->p
+   */
+  if (concat_p != NULL) {
+    LWIP_ASSERT("tcp_write: cannot concatenate when pcb->unsent is empty",
+      (last_unsent != NULL));
+    pbuf_cat(last_unsent->p, concat_p);
+    last_unsent->len += concat_p->tot_len;
+#if TCP_CHECKSUM_ON_COPY
+    if (concat_chksummed) {
+      tcp_seg_add_chksum(concat_chksum, concat_chksummed, &last_unsent->chksum,
+        &last_unsent->chksum_swapped);
+      last_unsent->flags |= TF_SEG_DATA_CHECKSUMMED;
+    }
+#endif /* TCP_CHECKSUM_ON_COPY */
+  }
+
+  /*
+   * Phase 3: Append queue to pcb->unsent. Queue may be NULL, but that
+   * is harmless
+   */
+  if (last_unsent == NULL) {
+    pcb->unsent = queue;
+  } else {
+    last_unsent->next = queue;
+  }
+
+  /*
+   * Finally update the pcb state.
+   */
+  pcb->snd_lbb += len;
+  pcb->snd_buf -= len;
+  pcb->snd_queuelen = queuelen;
+
+  LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: %"S16_F" (after enqueued)\n",
+    pcb->snd_queuelen));
+  if (pcb->snd_queuelen != 0) {
+    LWIP_ASSERT("tcp_write: valid queue length",
+                pcb->unacked != NULL || pcb->unsent != NULL);
+  }
+
+  /* Set the PSH flag in the last segment that we enqueued. */
+  if (seg != NULL && seg->tcphdr != NULL && ((apiflags & TCP_WRITE_FLAG_MORE)==0)) {
+    TCPH_SET_FLAG(seg->tcphdr, TCP_PSH);
+  }
+
+  return ERR_OK;
+memerr:
+  pcb->flags |= TF_NAGLEMEMERR;
+  TCP_STATS_INC(tcp.memerr);
+
+  if (concat_p != NULL) {
+    pbuf_free(concat_p);
+  }
+  if (queue != NULL) {
+    tcp_segs_free(queue);
+  }
+  if (pcb->snd_queuelen != 0) {
+    LWIP_ASSERT("tcp_write: valid queue length", pcb->unacked != NULL ||
+      pcb->unsent != NULL);
+  }
+  LWIP_DEBUGF(TCP_QLEN_DEBUG | LWIP_DBG_STATE, ("tcp_write: %"S16_F" (with mem err)\n", pcb->snd_queuelen));
+  return ERR_MEM;
+}
+
+/**
+ * Enqueue TCP options for transmission.
+ *
+ * Called by tcp_connect(), tcp_listen_input(), and tcp_send_ctrl().
+ *
+ * @param pcb Protocol control block for the TCP connection.
+ * @param flags TCP header flags to set in the outgoing segment.
+ * @param optdata pointer to TCP options, or NULL.
+ * @param optlen length of TCP options in bytes.
+ */
+err_t
+tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags)
+{
+  struct pbuf *p;
+  struct tcp_seg *seg;
+  u8_t optflags = 0;
+  u8_t optlen = 0;
+
+  LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
+
+  LWIP_ASSERT("tcp_enqueue_flags: need either TCP_SYN or TCP_FIN in flags (programmer violates API)",
+              (flags & (TCP_SYN | TCP_FIN)) != 0);
+
+  /* check for configured max queuelen and possible overflow */
+  if ((pcb->snd_queuelen >= TCP_SND_QUEUELEN) || (pcb->snd_queuelen > TCP_SNDQUEUELEN_OVERFLOW)) {
+    LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_enqueue_flags: too long queue %"U16_F" (max %"U16_F")\n",
+                                       pcb->snd_queuelen, TCP_SND_QUEUELEN));
+    TCP_STATS_INC(tcp.memerr);
+    pcb->flags |= TF_NAGLEMEMERR;
+    return ERR_MEM;
+  }
+
+  if (flags & TCP_SYN) {
+    optflags = TF_SEG_OPTS_MSS;
+  }
+#if LWIP_TCP_TIMESTAMPS
+  if ((pcb->flags & TF_TIMESTAMP)) {
+    optflags |= TF_SEG_OPTS_TS;
+  }
+#endif /* LWIP_TCP_TIMESTAMPS */
+  optlen = LWIP_TCP_OPT_LENGTH(optflags);
+
+  /* tcp_enqueue_flags is always called with either SYN or FIN in flags.
+   * We need one available snd_buf byte to do that.
+   * This means we can't send FIN while snd_buf==0. A better fix would be to
+   * not include SYN and FIN sequence numbers in the snd_buf count. */
+  if (pcb->snd_buf == 0) {
+    LWIP_DEBUGF(TCP_OUTPUT_DEBUG | 3, ("tcp_enqueue_flags: no send buffer available\n"));
+    TCP_STATS_INC(tcp.memerr);
+    return ERR_MEM;
+  }
+
+  /* Allocate pbuf with room for TCP header + options */
+  if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
+    pcb->flags |= TF_NAGLEMEMERR;
+    TCP_STATS_INC(tcp.memerr);
+    return ERR_MEM;
+  }
+  LWIP_ASSERT("tcp_enqueue_flags: check that first pbuf can hold optlen",
+              (p->len >= optlen));
+
+  /* Allocate memory for tcp_seg, and fill in fields. */
+  if ((seg = tcp_create_segment(pcb, p, flags, pcb->snd_lbb, optflags)) == NULL) {
+    pcb->flags |= TF_NAGLEMEMERR;
+    TCP_STATS_INC(tcp.memerr);
+    return ERR_MEM;
+  }
+  LWIP_ASSERT("seg->tcphdr not aligned", ((mem_ptr_t)seg->tcphdr % MEM_ALIGNMENT) == 0);
+  LWIP_ASSERT("tcp_enqueue_flags: invalid segment length", seg->len == 0);
+
+  LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_TRACE,
+              ("tcp_enqueue_flags: queueing %"U32_F":%"U32_F" (0x%"X16_F")\n",
+               ntohl(seg->tcphdr->seqno),
+               ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg),
+               (u16_t)flags));
+
+  /* Now append seg to pcb->unsent queue */
+  if (pcb->unsent == NULL) {
+    pcb->unsent = seg;
+  } else {
+    struct tcp_seg *useg;
+    for (useg = pcb->unsent; useg->next != NULL; useg = useg->next);
+    useg->next = seg;
+  }
+#if TCP_OVERSIZE
+  /* The new unsent tail has no space */
+  pcb->unsent_oversize = 0;
+#endif /* TCP_OVERSIZE */
+
+  /* SYN and FIN bump the sequence number */
+  if ((flags & TCP_SYN) || (flags & TCP_FIN)) {
+    pcb->snd_lbb++;
+    /* optlen does not influence snd_buf */
+    pcb->snd_buf--;
+  }
+  if (flags & TCP_FIN) {
+    pcb->flags |= TF_FIN;
+  }
+
+  /* update number of segments on the queues */
+  pcb->snd_queuelen += pbuf_clen(seg->p);
+  LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: %"S16_F" (after enqueued)\n", pcb->snd_queuelen));
+  if (pcb->snd_queuelen != 0) {
+    LWIP_ASSERT("tcp_enqueue_flags: invalid queue length",
+      pcb->unacked != NULL || pcb->unsent != NULL);
+  }
+
+  return ERR_OK;
+}
+ 
+
+#if LWIP_TCP_TIMESTAMPS
+/* Build a timestamp option (12 bytes long) at the specified options pointer)
+ *
+ * @param pcb tcp_pcb
+ * @param opts option pointer where to store the timestamp option
+ */
+static void
+tcp_build_timestamp_option(struct tcp_pcb *pcb, u32_t *opts)
+{
+  /* Pad with two NOP options to make everything nicely aligned */
+  opts[0] = PP_HTONL(0x0101080A);
+  opts[1] = htonl(sys_now());
+  opts[2] = htonl(pcb->ts_recent);
+}
+#endif
+
+/** Send an ACK without data.
+ *
+ * @param pcb Protocol control block for the TCP connection to send the ACK
+ */
+err_t
+tcp_send_empty_ack(struct tcp_pcb *pcb)
+{
+  struct pbuf *p;
+  struct tcp_hdr *tcphdr;
+  u8_t optlen = 0;
+
+#if LWIP_TCP_TIMESTAMPS
+  if (pcb->flags & TF_TIMESTAMP) {
+    optlen = LWIP_TCP_OPT_LENGTH(TF_SEG_OPTS_TS);
+  }
+#endif
+
+  p = tcp_output_alloc_header(pcb, optlen, 0, htonl(pcb->snd_nxt));
+  if (p == NULL) {
+    LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: (ACK) could not allocate pbuf\n"));
+    return ERR_BUF;
+  }
+  tcphdr = (struct tcp_hdr *)p->payload;
+  LWIP_DEBUGF(TCP_OUTPUT_DEBUG, 
+              ("tcp_output: sending ACK for %"U32_F"\n", pcb->rcv_nxt));
+  /* remove ACK flags from the PCB, as we send an empty ACK now */
+  pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
+
+  /* NB. MSS option is only sent on SYNs, so ignore it here */
+#if LWIP_TCP_TIMESTAMPS
+  pcb->ts_lastacksent = pcb->rcv_nxt;
+
+  if (pcb->flags & TF_TIMESTAMP) {
+    tcp_build_timestamp_option(pcb, (u32_t *)(tcphdr + 1));
+  }
+#endif 
+
+#if CHECKSUM_GEN_TCP
+  tcphdr->chksum = inet_chksum_pseudo(p, &(pcb->local_ip), &(pcb->remote_ip),
+        IP_PROTO_TCP, p->tot_len);
+#endif
+#if LWIP_NETIF_HWADDRHINT
+  ip_output_hinted(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
+      IP_PROTO_TCP, &(pcb->addr_hint));
+#else /* LWIP_NETIF_HWADDRHINT*/
+  ip_output(p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
+      IP_PROTO_TCP);
+#endif /* LWIP_NETIF_HWADDRHINT*/
+  pbuf_free(p);
+
+  return ERR_OK;
+}
+
+/**
+ * Find out what we can send and send it
+ *
+ * @param pcb Protocol control block for the TCP connection to send data
+ * @return ERR_OK if data has been sent or nothing to send
+ *         another err_t on error
+ */
+err_t
+tcp_output(struct tcp_pcb *pcb)
+{
+  struct tcp_seg *seg, *useg;
+  u32_t wnd, snd_nxt;
+#if TCP_CWND_DEBUG
+  s16_t i = 0;
+#endif /* TCP_CWND_DEBUG */
+
+  /* First, check if we are invoked by the TCP input processing
+     code. If so, we do not output anything. Instead, we rely on the
+     input processing code to call us when input processing is done
+     with. */
+  if (tcp_input_pcb == pcb) {
+    return ERR_OK;
+  }
+
+  wnd = LWIP_MIN(pcb->snd_wnd, pcb->cwnd);
+
+  seg = pcb->unsent;
+
+  /* If the TF_ACK_NOW flag is set and no data will be sent (either
+   * because the ->unsent queue is empty or because the window does
+   * not allow it), construct an empty ACK segment and send it.
+   *
+   * If data is to be sent, we will just piggyback the ACK (see below).
+   */
+  if (pcb->flags & TF_ACK_NOW &&
+     (seg == NULL ||
+      ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > wnd)) {
+     return tcp_send_empty_ack(pcb);
+  }
+
+  /* useg should point to last segment on unacked queue */
+  useg = pcb->unacked;
+  if (useg != NULL) {
+    for (; useg->next != NULL; useg = useg->next);
+  }
+
+#if TCP_OUTPUT_DEBUG
+  if (seg == NULL) {
+    LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: nothing to send (%p)\n",
+                                   (void*)pcb->unsent));
+  }
+#endif /* TCP_OUTPUT_DEBUG */
+#if TCP_CWND_DEBUG
+  if (seg == NULL) {
+    LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U16_F
+                                 ", cwnd %"U16_F", wnd %"U32_F
+                                 ", seg == NULL, ack %"U32_F"\n",
+                                 pcb->snd_wnd, pcb->cwnd, wnd, pcb->lastack));
+  } else {
+    LWIP_DEBUGF(TCP_CWND_DEBUG, 
+                ("tcp_output: snd_wnd %"U16_F", cwnd %"U16_F", wnd %"U32_F
+                 ", effwnd %"U32_F", seq %"U32_F", ack %"U32_F"\n",
+                 pcb->snd_wnd, pcb->cwnd, wnd,
+                 ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len,
+                 ntohl(seg->tcphdr->seqno), pcb->lastack));
+  }
+#endif /* TCP_CWND_DEBUG */
+  /* data available and window allows it to be sent? */
+  while (seg != NULL &&
+         ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len <= wnd) {
+    LWIP_ASSERT("RST not expected here!", 
+                (TCPH_FLAGS(seg->tcphdr) & TCP_RST) == 0);
+    /* Stop sending if the nagle algorithm would prevent it
+     * Don't stop:
+     * - if tcp_write had a memory error before (prevent delayed ACK timeout) or
+     * - if FIN was already enqueued for this PCB (SYN is always alone in a segment -
+     *   either seg->next != NULL or pcb->unacked == NULL;
+     *   RST is no sent using tcp_write/tcp_output.
+     */
+    if((tcp_do_output_nagle(pcb) == 0) &&
+      ((pcb->flags & (TF_NAGLEMEMERR | TF_FIN)) == 0)){
+      break;
+    }
+#if TCP_CWND_DEBUG
+    LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"U16_F", cwnd %"U16_F", wnd %"U32_F", effwnd %"U32_F", seq %"U32_F", ack %"U32_F", i %"S16_F"\n",
+                            pcb->snd_wnd, pcb->cwnd, wnd,
+                            ntohl(seg->tcphdr->seqno) + seg->len -
+                            pcb->lastack,
+                            ntohl(seg->tcphdr->seqno), pcb->lastack, i));
+    ++i;
+#endif /* TCP_CWND_DEBUG */
+
+    pcb->unsent = seg->next;
+
+    if (pcb->state != SYN_SENT) {
+      TCPH_SET_FLAG(seg->tcphdr, TCP_ACK);
+      pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
+    }
+
+    tcp_output_segment(seg, pcb);
+    snd_nxt = ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg);
+    if (TCP_SEQ_LT(pcb->snd_nxt, snd_nxt)) {
+      pcb->snd_nxt = snd_nxt;
+    }
+    /* put segment on unacknowledged list if length > 0 */
+    if (TCP_TCPLEN(seg) > 0) {
+      seg->next = NULL;
+      /* unacked list is empty? */
+      if (pcb->unacked == NULL) {
+        pcb->unacked = seg;
+        useg = seg;
+      /* unacked list is not empty? */
+      } else {
+        /* In the case of fast retransmit, the packet should not go to the tail
+         * of the unacked queue, but rather somewhere before it. We need to check for
+         * this case. -STJ Jul 27, 2004 */
+        if (TCP_SEQ_LT(ntohl(seg->tcphdr->seqno), ntohl(useg->tcphdr->seqno))) {
+          /* add segment to before tail of unacked list, keeping the list sorted */
+          struct tcp_seg **cur_seg = &(pcb->unacked);
+          while (*cur_seg &&
+            TCP_SEQ_LT(ntohl((*cur_seg)->tcphdr->seqno), ntohl(seg->tcphdr->seqno))) {
+              cur_seg = &((*cur_seg)->next );
+          }
+          seg->next = (*cur_seg);
+          (*cur_seg) = seg;
+        } else {
+          /* add segment to tail of unacked list */
+          useg->next = seg;
+          useg = useg->next;
+        }
+      }
+    /* do not queue empty segments on the unacked list */
+    } else {
+      tcp_seg_free(seg);
+    }
+    seg = pcb->unsent;
+  }
+#if TCP_OVERSIZE
+  if (pcb->unsent == NULL) {
+    /* last unsent has been removed, reset unsent_oversize */
+    pcb->unsent_oversize = 0;
+  }
+#endif /* TCP_OVERSIZE */
+
+  if (seg != NULL && pcb->persist_backoff == 0 && 
+      ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > pcb->snd_wnd) {
+    /* prepare for persist timer */
+    pcb->persist_cnt = 0;
+    pcb->persist_backoff = 1;
+  }
+
+  pcb->flags &= ~TF_NAGLEMEMERR;
+  return ERR_OK;
+}
+
+/**
+ * Called by tcp_output() to actually send a TCP segment over IP.
+ *
+ * @param seg the tcp_seg to send
+ * @param pcb the tcp_pcb for the TCP connection used to send the segment
+ */
+static void
+tcp_output_segment(struct tcp_seg *seg, struct tcp_pcb *pcb)
+{
+  u16_t len;
+  struct netif *netif;
+  u32_t *opts;
+
+  /** @bug Exclude retransmitted segments from this count. */
+  snmp_inc_tcpoutsegs();
+
+  /* The TCP header has already been constructed, but the ackno and
+   wnd fields remain. */
+  seg->tcphdr->ackno = htonl(pcb->rcv_nxt);
+
+  /* advertise our receive window size in this TCP segment */
+  seg->tcphdr->wnd = htons(pcb->rcv_ann_wnd);
+
+  pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
+
+  /* Add any requested options.  NB MSS option is only set on SYN
+     packets, so ignore it here */
+  LWIP_ASSERT("seg->tcphdr not aligned", ((mem_ptr_t)seg->tcphdr % MEM_ALIGNMENT) == 0);
+  opts = (u32_t *)(void *)(seg->tcphdr + 1);
+  if (seg->flags & TF_SEG_OPTS_MSS) {
+    TCP_BUILD_MSS_OPTION(*opts);
+    opts += 1;
+  }
+#if LWIP_TCP_TIMESTAMPS
+  pcb->ts_lastacksent = pcb->rcv_nxt;
+
+  if (seg->flags & TF_SEG_OPTS_TS) {
+    tcp_build_timestamp_option(pcb, opts);
+    opts += 3;
+  }
+#endif
+
+  /* Set retransmission timer running if it is not currently enabled 
+     This must be set before checking the route. */
+  if (pcb->rtime == -1) {
+    pcb->rtime = 0;
+  }
+
+  /* If we don't have a local IP address, we get one by
+     calling ip_route(). */
+  if (ip_addr_isany(&(pcb->local_ip))) {
+    netif = ip_route(&(pcb->remote_ip));
+    if (netif == NULL) {
+      return;
+    }
+    ip_addr_copy(pcb->local_ip, netif->ip_addr);
+  }
+
+  if (pcb->rttest == 0) {
+    pcb->rttest = tcp_ticks;
+    pcb->rtseq = ntohl(seg->tcphdr->seqno);
+
+    LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_output_segment: rtseq %"U32_F"\n", pcb->rtseq));
+  }
+  LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: %"U32_F":%"U32_F"\n",
+          htonl(seg->tcphdr->seqno), htonl(seg->tcphdr->seqno) +
+          seg->len));
+
+  len = (u16_t)((u8_t *)seg->tcphdr - (u8_t *)seg->p->payload);
+
+  seg->p->len -= len;
+  seg->p->tot_len -= len;
+
+  seg->p->payload = seg->tcphdr;
+
+  seg->tcphdr->chksum = 0;
+#if CHECKSUM_GEN_TCP
+#if TCP_CHECKSUM_ON_COPY
+  {
+    u32_t acc;
+#if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
+    u16_t chksum_slow = inet_chksum_pseudo(seg->p, &(pcb->local_ip),
+           &(pcb->remote_ip),
+           IP_PROTO_TCP, seg->p->tot_len);
+#endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
+    if ((seg->flags & TF_SEG_DATA_CHECKSUMMED) == 0) {
+      LWIP_ASSERT("data included but not checksummed",
+        seg->p->tot_len == (TCPH_HDRLEN(seg->tcphdr) * 4));
+    }
+
+    /* rebuild TCP header checksum (TCP header changes for retransmissions!) */
+    acc = inet_chksum_pseudo_partial(seg->p, &(pcb->local_ip),
+             &(pcb->remote_ip),
+             IP_PROTO_TCP, seg->p->tot_len, TCPH_HDRLEN(seg->tcphdr) * 4);
+    /* add payload checksum */
+    if (seg->chksum_swapped) {
+      seg->chksum = SWAP_BYTES_IN_WORD(seg->chksum);
+      seg->chksum_swapped = 0;
+    }
+    acc += (u16_t)~(seg->chksum);
+    seg->tcphdr->chksum = FOLD_U32T(acc);
+#if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
+    if (chksum_slow != seg->tcphdr->chksum) {
+      LWIP_DEBUGF(TCP_DEBUG | LWIP_DBG_LEVEL_WARNING,
+                  ("tcp_output_segment: calculated checksum is %"X16_F" instead of %"X16_F"\n",
+                  seg->tcphdr->chksum, chksum_slow));
+      seg->tcphdr->chksum = chksum_slow;
+    }
+#endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
+  }
+#else /* TCP_CHECKSUM_ON_COPY */
+  seg->tcphdr->chksum = inet_chksum_pseudo(seg->p, &(pcb->local_ip),
+         &(pcb->remote_ip),
+         IP_PROTO_TCP, seg->p->tot_len);
+#endif /* TCP_CHECKSUM_ON_COPY */
+#endif /* CHECKSUM_GEN_TCP */
+  TCP_STATS_INC(tcp.xmit);
+
+#if LWIP_NETIF_HWADDRHINT
+  ip_output_hinted(seg->p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
+      IP_PROTO_TCP, &(pcb->addr_hint));
+#else /* LWIP_NETIF_HWADDRHINT*/
+  ip_output(seg->p, &(pcb->local_ip), &(pcb->remote_ip), pcb->ttl, pcb->tos,
+      IP_PROTO_TCP);
+#endif /* LWIP_NETIF_HWADDRHINT*/
+}
+
+/**
+ * Send a TCP RESET packet (empty segment with RST flag set) either to
+ * abort a connection or to show that there is no matching local connection
+ * for a received segment.
+ *
+ * Called by tcp_abort() (to abort a local connection), tcp_input() (if no
+ * matching local pcb was found), tcp_listen_input() (if incoming segment
+ * has ACK flag set) and tcp_process() (received segment in the wrong state)
+ *
+ * Since a RST segment is in most cases not sent for an active connection,
+ * tcp_rst() has a number of arguments that are taken from a tcp_pcb for
+ * most other segment output functions.
+ *
+ * @param seqno the sequence number to use for the outgoing segment
+ * @param ackno the acknowledge number to use for the outgoing segment
+ * @param local_ip the local IP address to send the segment from
+ * @param remote_ip the remote IP address to send the segment to
+ * @param local_port the local TCP port to send the segment from
+ * @param remote_port the remote TCP port to send the segment to
+ */
+void
+tcp_rst(u32_t seqno, u32_t ackno,
+  ip_addr_t *local_ip, ip_addr_t *remote_ip,
+  u16_t local_port, u16_t remote_port)
+{
+  struct pbuf *p;
+  struct tcp_hdr *tcphdr;
+  p = pbuf_alloc(PBUF_IP, TCP_HLEN, PBUF_RAM);
+  if (p == NULL) {
+      LWIP_DEBUGF(TCP_DEBUG, ("tcp_rst: could not allocate memory for pbuf\n"));
+      return;
+  }
+  LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
+              (p->len >= sizeof(struct tcp_hdr)));
+
+  tcphdr = (struct tcp_hdr *)p->payload;
+  tcphdr->src = htons(local_port);
+  tcphdr->dest = htons(remote_port);
+  tcphdr->seqno = htonl(seqno);
+  tcphdr->ackno = htonl(ackno);
+  TCPH_HDRLEN_FLAGS_SET(tcphdr, TCP_HLEN/4, TCP_RST | TCP_ACK);
+  tcphdr->wnd = PP_HTONS(TCP_WND);
+  tcphdr->chksum = 0;
+  tcphdr->urgp = 0;
+
+#if CHECKSUM_GEN_TCP
+  tcphdr->chksum = inet_chksum_pseudo(p, local_ip, remote_ip,
+              IP_PROTO_TCP, p->tot_len);
+#endif
+  TCP_STATS_INC(tcp.xmit);
+  snmp_inc_tcpoutrsts();
+   /* Send output with hardcoded TTL since we have no access to the pcb */
+  ip_output(p, local_ip, remote_ip, TCP_TTL, 0, IP_PROTO_TCP);
+  pbuf_free(p);
+  LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_rst: seqno %"U32_F" ackno %"U32_F".\n", seqno, ackno));
+}
+
+/**
+ * Requeue all unacked segments for retransmission
+ *
+ * Called by tcp_slowtmr() for slow retransmission.
+ *
+ * @param pcb the tcp_pcb for which to re-enqueue all unacked segments
+ */
+void
+tcp_rexmit_rto(struct tcp_pcb *pcb)
+{
+  struct tcp_seg *seg;
+
+  if (pcb->unacked == NULL) {
+    return;
+  }
+
+  /* Move all unacked segments to the head of the unsent queue */
+  for (seg = pcb->unacked; seg->next != NULL; seg = seg->next);
+  /* concatenate unsent queue after unacked queue */
+  seg->next = pcb->unsent;
+  /* unsent queue is the concatenated queue (of unacked, unsent) */
+  pcb->unsent = pcb->unacked;
+  /* unacked queue is now empty */
+  pcb->unacked = NULL;
+
+  /* increment number of retransmissions */
+  ++pcb->nrtx;
+
+  /* Don't take any RTT measurements after retransmitting. */
+  pcb->rttest = 0;
+
+  /* Do the actual retransmission */
+  tcp_output(pcb);
+}
+
+/**
+ * Requeue the first unacked segment for retransmission
+ *
+ * Called by tcp_receive() for fast retramsmit.
+ *
+ * @param pcb the tcp_pcb for which to retransmit the first unacked segment
+ */
+void
+tcp_rexmit(struct tcp_pcb *pcb)
+{
+  struct tcp_seg *seg;
+  struct tcp_seg **cur_seg;
+
+  if (pcb->unacked == NULL) {
+    return;
+  }
+
+  /* Move the first unacked segment to the unsent queue */
+  /* Keep the unsent queue sorted. */
+  seg = pcb->unacked;
+  pcb->unacked = seg->next;
+
+  cur_seg = &(pcb->unsent);
+  while (*cur_seg &&
+    TCP_SEQ_LT(ntohl((*cur_seg)->tcphdr->seqno), ntohl(seg->tcphdr->seqno))) {
+      cur_seg = &((*cur_seg)->next );
+  }
+  seg->next = *cur_seg;
+  *cur_seg = seg;
+
+  ++pcb->nrtx;
+
+  /* Don't take any rtt measurements after retransmitting. */
+  pcb->rttest = 0;
+
+  /* Do the actual retransmission. */
+  snmp_inc_tcpretranssegs();
+  /* No need to call tcp_output: we are always called from tcp_input()
+     and thus tcp_output directly returns. */
+}
+
+
+/**
+ * Handle retransmission after three dupacks received
+ *
+ * @param pcb the tcp_pcb for which to retransmit the first unacked segment
+ */
+void 
+tcp_rexmit_fast(struct tcp_pcb *pcb)
+{
+  if (pcb->unacked != NULL && !(pcb->flags & TF_INFR)) {
+    /* This is fast retransmit. Retransmit the first unacked segment. */
+    LWIP_DEBUGF(TCP_FR_DEBUG, 
+                ("tcp_receive: dupacks %"U16_F" (%"U32_F
+                 "), fast retransmit %"U32_F"\n",
+                 (u16_t)pcb->dupacks, pcb->lastack,
+                 ntohl(pcb->unacked->tcphdr->seqno)));
+    tcp_rexmit(pcb);
+
+    /* Set ssthresh to half of the minimum of the current
+     * cwnd and the advertised window */
+    if (pcb->cwnd > pcb->snd_wnd) {
+      pcb->ssthresh = pcb->snd_wnd / 2;
+    } else {
+      pcb->ssthresh = pcb->cwnd / 2;
+    }
+    
+    /* The minimum value for ssthresh should be 2 MSS */
+    if (pcb->ssthresh < 2*pcb->mss) {
+      LWIP_DEBUGF(TCP_FR_DEBUG, 
+                  ("tcp_receive: The minimum value for ssthresh %"U16_F
+                   " should be min 2 mss %"U16_F"...\n",
+                   pcb->ssthresh, 2*pcb->mss));
+      pcb->ssthresh = 2*pcb->mss;
+    }
+    
+    pcb->cwnd = pcb->ssthresh + 3 * pcb->mss;
+    pcb->flags |= TF_INFR;
+  } 
+}
+
+
+/**
+ * Send keepalive packets to keep a connection active although
+ * no data is sent over it.
+ *
+ * Called by tcp_slowtmr()
+ *
+ * @param pcb the tcp_pcb for which to send a keepalive packet
+ */
+void
+tcp_keepalive(struct tcp_pcb *pcb)
+{
+  struct pbuf *p;
+  struct tcp_hdr *tcphdr;
+
+  LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: sending KEEPALIVE probe to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+                          ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip),
+                          ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip)));
+
+  LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: tcp_ticks %"U32_F"   pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n", 
+                          tcp_ticks, pcb->tmr, pcb->keep_cnt_sent));
+   
+  p = tcp_output_alloc_header(pcb, 0, 0, htonl(pcb->snd_nxt - 1));
+  if(p == NULL) {
+    LWIP_DEBUGF(TCP_DEBUG, 
+                ("tcp_keepalive: could not allocate memory for pbuf\n"));
+    return;
+  }
+  tcphdr = (struct tcp_hdr *)p->payload;
+
+#if CHECKSUM_GEN_TCP
+  tcphdr->chksum = inet_chksum_pseudo(p, &pcb->local_ip, &pcb->remote_ip,
+                                      IP_PROTO_TCP, p->tot_len);
+#endif
+  TCP_STATS_INC(tcp.xmit);
+
+  /* Send output to IP */
+#if LWIP_NETIF_HWADDRHINT
+  ip_output_hinted(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP,
+    &(pcb->addr_hint));
+#else /* LWIP_NETIF_HWADDRHINT*/
+  ip_output(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP);
+#endif /* LWIP_NETIF_HWADDRHINT*/
+
+  pbuf_free(p);
+
+  LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: seqno %"U32_F" ackno %"U32_F".\n",
+                          pcb->snd_nxt - 1, pcb->rcv_nxt));
+}
+
+
+/**
+ * Send persist timer zero-window probes to keep a connection active
+ * when a window update is lost.
+ *
+ * Called by tcp_slowtmr()
+ *
+ * @param pcb the tcp_pcb for which to send a zero-window probe packet
+ */
+void
+tcp_zero_window_probe(struct tcp_pcb *pcb)
+{
+  struct pbuf *p;
+  struct tcp_hdr *tcphdr;
+  struct tcp_seg *seg;
+  u16_t len;
+  u8_t is_fin;
+
+  LWIP_DEBUGF(TCP_DEBUG, 
+              ("tcp_zero_window_probe: sending ZERO WINDOW probe to %"
+               U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+               ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip),
+               ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip)));
+
+  LWIP_DEBUGF(TCP_DEBUG, 
+              ("tcp_zero_window_probe: tcp_ticks %"U32_F
+               "   pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n", 
+               tcp_ticks, pcb->tmr, pcb->keep_cnt_sent));
+
+  seg = pcb->unacked;
+
+  if(seg == NULL) {
+    seg = pcb->unsent;
+  }
+  if(seg == NULL) {
+    return;
+  }
+
+  is_fin = ((TCPH_FLAGS(seg->tcphdr) & TCP_FIN) != 0) && (seg->len == 0);
+  /* we want to send one seqno: either FIN or data (no options) */
+  len = is_fin ? 0 : 1;
+
+  p = tcp_output_alloc_header(pcb, 0, len, seg->tcphdr->seqno);
+  if(p == NULL) {
+    LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: no memory for pbuf\n"));
+    return;
+  }
+  tcphdr = (struct tcp_hdr *)p->payload;
+
+  if (is_fin) {
+    /* FIN segment, no data */
+    TCPH_FLAGS_SET(tcphdr, TCP_ACK | TCP_FIN);
+  } else {
+    /* Data segment, copy in one byte from the head of the unacked queue */
+    struct tcp_hdr *thdr = (struct tcp_hdr *)seg->p->payload;
+    char *d = ((char *)p->payload + TCP_HLEN);
+    pbuf_copy_partial(seg->p, d, 1, TCPH_HDRLEN(thdr) * 4);
+  }
+
+#if CHECKSUM_GEN_TCP
+  tcphdr->chksum = inet_chksum_pseudo(p, &pcb->local_ip, &pcb->remote_ip,
+                                      IP_PROTO_TCP, p->tot_len);
+#endif
+  TCP_STATS_INC(tcp.xmit);
+
+  /* Send output to IP */
+#if LWIP_NETIF_HWADDRHINT
+  ip_output_hinted(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP,
+    &(pcb->addr_hint));
+#else /* LWIP_NETIF_HWADDRHINT*/
+  ip_output(p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl, 0, IP_PROTO_TCP);
+#endif /* LWIP_NETIF_HWADDRHINT*/
+
+  pbuf_free(p);
+
+  LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: seqno %"U32_F
+                          " ackno %"U32_F".\n",
+                          pcb->snd_nxt - 1, pcb->rcv_nxt));
+}
+#endif /* LWIP_TCP */
diff --git a/core/lwip/src/core/timers.c b/core/lwip/src/core/timers.c
new file mode 100644
index 00000000..4e94f0d1
--- /dev/null
+++ b/core/lwip/src/core/timers.c
@@ -0,0 +1,483 @@
+/**
+ * @file
+ * Stack-internal timers implementation.
+ * This file includes timer callbacks for stack-internal timers as well as
+ * functions to set up or stop timers and check for expired timers.
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *         Simon Goldschmidt
+ *
+ */
+
+#include "lwip/opt.h"
+
+#include "lwip/timers.h"
+#include "lwip/tcp_impl.h"
+
+#if LWIP_TIMERS
+
+#include "lwip/def.h"
+#include "lwip/memp.h"
+#include "lwip/tcpip.h"
+
+#include "lwip/ip_frag.h"
+#include "netif/etharp.h"
+#include "lwip/dhcp.h"
+#include "lwip/autoip.h"
+#include "lwip/igmp.h"
+#include "lwip/dns.h"
+
+
+/** The one and only timeout list */
+static struct sys_timeo *next_timeout;
+#if NO_SYS
+static u32_t timeouts_last_time;
+#endif /* NO_SYS */
+
+#if LWIP_TCP
+/** global variable that shows if the tcp timer is currently scheduled or not */
+static int tcpip_tcp_timer_active;
+
+/**
+ * Timer callback function that calls tcp_tmr() and reschedules itself.
+ *
+ * @param arg unused argument
+ */
+static void
+tcpip_tcp_timer(void *arg)
+{
+  LWIP_UNUSED_ARG(arg);
+
+  /* call TCP timer handler */
+  tcp_tmr();
+  /* timer still needed? */
+  if (tcp_active_pcbs || tcp_tw_pcbs) {
+    /* restart timer */
+    sys_timeout(TCP_TMR_INTERVAL, tcpip_tcp_timer, NULL);
+  } else {
+    /* disable timer */
+    tcpip_tcp_timer_active = 0;
+  }
+}
+
+/**
+ * Called from TCP_REG when registering a new PCB:
+ * the reason is to have the TCP timer only running when
+ * there are active (or time-wait) PCBs.
+ */
+void
+tcp_timer_needed(void)
+{
+  /* timer is off but needed again? */
+  if (!tcpip_tcp_timer_active && (tcp_active_pcbs || tcp_tw_pcbs)) {
+    /* enable and start timer */
+    tcpip_tcp_timer_active = 1;
+    sys_timeout(TCP_TMR_INTERVAL, tcpip_tcp_timer, NULL);
+  }
+}
+#endif /* LWIP_TCP */
+
+#if IP_REASSEMBLY
+/**
+ * Timer callback function that calls ip_reass_tmr() and reschedules itself.
+ *
+ * @param arg unused argument
+ */
+static void
+ip_reass_timer(void *arg)
+{
+  LWIP_UNUSED_ARG(arg);
+  LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: ip_reass_tmr()\n"));
+  ip_reass_tmr();
+  sys_timeout(IP_TMR_INTERVAL, ip_reass_timer, NULL);
+}
+#endif /* IP_REASSEMBLY */
+
+#if LWIP_ARP
+/**
+ * Timer callback function that calls etharp_tmr() and reschedules itself.
+ *
+ * @param arg unused argument
+ */
+static void
+arp_timer(void *arg)
+{
+  LWIP_UNUSED_ARG(arg);
+  LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: etharp_tmr()\n"));
+  etharp_tmr();
+  undiarp_tmr();
+  sys_timeout(ARP_TMR_INTERVAL, arp_timer, NULL);
+}
+#endif /* LWIP_ARP */
+
+#if LWIP_DHCP
+/**
+ * Timer callback function that calls dhcp_coarse_tmr() and reschedules itself.
+ *
+ * @param arg unused argument
+ */
+static void
+dhcp_timer_coarse(void *arg)
+{
+  LWIP_UNUSED_ARG(arg);
+  LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: dhcp_coarse_tmr()\n"));
+  dhcp_coarse_tmr();
+  sys_timeout(DHCP_COARSE_TIMER_MSECS, dhcp_timer_coarse, NULL);
+}
+
+/**
+ * Timer callback function that calls dhcp_fine_tmr() and reschedules itself.
+ *
+ * @param arg unused argument
+ */
+static void
+dhcp_timer_fine(void *arg)
+{
+  LWIP_UNUSED_ARG(arg);
+  LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: dhcp_fine_tmr()\n"));
+  dhcp_fine_tmr();
+  sys_timeout(DHCP_FINE_TIMER_MSECS, dhcp_timer_fine, NULL);
+}
+#endif /* LWIP_DHCP */
+
+#if LWIP_AUTOIP
+/**
+ * Timer callback function that calls autoip_tmr() and reschedules itself.
+ *
+ * @param arg unused argument
+ */
+static void
+autoip_timer(void *arg)
+{
+  LWIP_UNUSED_ARG(arg);
+  LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: autoip_tmr()\n"));
+  autoip_tmr();
+  sys_timeout(AUTOIP_TMR_INTERVAL, autoip_timer, NULL);
+}
+#endif /* LWIP_AUTOIP */
+
+#if LWIP_IGMP
+/**
+ * Timer callback function that calls igmp_tmr() and reschedules itself.
+ *
+ * @param arg unused argument
+ */
+static void
+igmp_timer(void *arg)
+{
+  LWIP_UNUSED_ARG(arg);
+  LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: igmp_tmr()\n"));
+  igmp_tmr();
+  sys_timeout(IGMP_TMR_INTERVAL, igmp_timer, NULL);
+}
+#endif /* LWIP_IGMP */
+
+#if LWIP_DNS
+/**
+ * Timer callback function that calls dns_tmr() and reschedules itself.
+ *
+ * @param arg unused argument
+ */
+static void
+dns_timer(void *arg)
+{
+  LWIP_UNUSED_ARG(arg);
+  LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: dns_tmr()\n"));
+  dns_tmr();
+  sys_timeout(DNS_TMR_INTERVAL, dns_timer, NULL);
+}
+#endif /* LWIP_DNS */
+
+/** Initialize this module */
+void sys_timeouts_init(void)
+{
+#if IP_REASSEMBLY
+  sys_timeout(IP_TMR_INTERVAL, ip_reass_timer, NULL);
+#endif /* IP_REASSEMBLY */
+#if LWIP_ARP
+  sys_timeout(ARP_TMR_INTERVAL, arp_timer, NULL);
+#endif /* LWIP_ARP */
+#if LWIP_DHCP
+  sys_timeout(DHCP_COARSE_TIMER_MSECS, dhcp_timer_coarse, NULL);
+  sys_timeout(DHCP_FINE_TIMER_MSECS, dhcp_timer_fine, NULL);
+#endif /* LWIP_DHCP */
+#if LWIP_AUTOIP
+  sys_timeout(AUTOIP_TMR_INTERVAL, autoip_timer, NULL);
+#endif /* LWIP_AUTOIP */
+#if LWIP_IGMP
+  sys_timeout(IGMP_TMR_INTERVAL, igmp_timer, NULL);
+#endif /* LWIP_IGMP */
+#if LWIP_DNS
+  sys_timeout(DNS_TMR_INTERVAL, dns_timer, NULL);
+#endif /* LWIP_DNS */
+
+#if NO_SYS
+  /* Initialise timestamp for sys_check_timeouts */
+  timeouts_last_time = sys_now();
+#endif
+}
+
+/**
+ * Create a one-shot timer (aka timeout). Timeouts are processed in the
+ * following cases:
+ * - while waiting for a message using sys_timeouts_mbox_fetch()
+ * - by calling sys_check_timeouts() (NO_SYS==1 only)
+ *
+ * @param msecs time in milliseconds after that the timer should expire
+ * @param handler callback function to call when msecs have elapsed
+ * @param arg argument to pass to the callback function
+ */
+#if LWIP_DEBUG_TIMERNAMES
+void
+sys_timeout_debug(u32_t msecs, sys_timeout_handler handler, void *arg, const char* handler_name)
+#else /* LWIP_DEBUG_TIMERNAMES */
+void
+sys_timeout(u32_t msecs, sys_timeout_handler handler, void *arg)
+#endif /* LWIP_DEBUG_TIMERNAMES */
+{
+  struct sys_timeo *timeout, *t;
+
+  timeout = (struct sys_timeo *)memp_malloc(MEMP_SYS_TIMEOUT);
+  if (timeout == NULL) {
+    LWIP_ASSERT("sys_timeout: timeout != NULL, pool MEMP_SYS_TIMEOUT is empty", timeout != NULL);
+    return;
+  }
+  timeout->next = NULL;
+  timeout->h = handler;
+  timeout->arg = arg;
+  timeout->time = msecs;
+#if LWIP_DEBUG_TIMERNAMES
+  timeout->handler_name = handler_name;
+  LWIP_DEBUGF(TIMERS_DEBUG, ("sys_timeout: %p msecs=%"U32_F" handler=%s arg=%p\n",
+    (void *)timeout, msecs, handler_name, (void *)arg));
+#endif /* LWIP_DEBUG_TIMERNAMES */
+
+  if (next_timeout == NULL) {
+    next_timeout = timeout;
+    return;
+  }
+
+  if (next_timeout->time > msecs) {
+    next_timeout->time -= msecs;
+    timeout->next = next_timeout;
+    next_timeout = timeout;
+  } else {
+    for(t = next_timeout; t != NULL; t = t->next) {
+      timeout->time -= t->time;
+      if (t->next == NULL || t->next->time > timeout->time) {
+        if (t->next != NULL) {
+          t->next->time -= timeout->time;
+        }
+        timeout->next = t->next;
+        t->next = timeout;
+        break;
+      }
+    }
+  }
+}
+
+/**
+ * Go through timeout list (for this task only) and remove the first matching
+ * entry, even though the timeout has not triggered yet.
+ *
+ * @note This function only works as expected if there is only one timeout
+ * calling 'handler' in the list of timeouts.
+ *
+ * @param handler callback function that would be called by the timeout
+ * @param arg callback argument that would be passed to handler
+*/
+void
+sys_untimeout(sys_timeout_handler handler, void *arg)
+{
+  struct sys_timeo *prev_t, *t;
+
+  if (next_timeout == NULL) {
+    return;
+  }
+
+  for (t = next_timeout, prev_t = NULL; t != NULL; prev_t = t, t = t->next) {
+    if ((t->h == handler) && (t->arg == arg)) {
+      /* We have a match */
+      /* Unlink from previous in list */
+      if (prev_t == NULL) {
+        next_timeout = t->next;
+      } else {
+        prev_t->next = t->next;
+      }
+      /* If not the last one, add time of this one back to next */
+      if (t->next != NULL) {
+        t->next->time += t->time;
+      }
+      memp_free(MEMP_SYS_TIMEOUT, t);
+      return;
+    }
+  }
+  return;
+}
+
+#if NO_SYS
+
+/** Handle timeouts for NO_SYS==1 (i.e. without using
+ * tcpip_thread/sys_timeouts_mbox_fetch(). Uses sys_now() to call timeout
+ * handler functions when timeouts expire.
+ *
+ * Must be called periodically from your main loop.
+ */
+void
+sys_check_timeouts(void)
+{
+  struct sys_timeo *tmptimeout;
+  u32_t diff;
+  sys_timeout_handler handler;
+  void *arg;
+  int had_one;
+  u32_t now;
+
+  now = sys_now();
+  if (next_timeout) {
+    /* this cares for wraparounds */
+    diff = LWIP_U32_DIFF(now, timeouts_last_time);
+    do
+    {
+      had_one = 0;
+      tmptimeout = next_timeout;
+      if (tmptimeout->time <= diff) {
+        /* timeout has expired */
+        had_one = 1;
+        timeouts_last_time = now;
+        diff -= tmptimeout->time;
+        next_timeout = tmptimeout->next;
+        handler = tmptimeout->h;
+        arg = tmptimeout->arg;
+#if LWIP_DEBUG_TIMERNAMES
+        if (handler != NULL) {
+          LWIP_DEBUGF(TIMERS_DEBUG, ("sct calling h=%s arg=%p\n",
+            tmptimeout->handler_name, arg));
+        }
+#endif /* LWIP_DEBUG_TIMERNAMES */
+        memp_free(MEMP_SYS_TIMEOUT, tmptimeout);
+        if (handler != NULL) {
+          handler(arg);
+        }
+      }
+    /* repeat until all expired timers have been called */
+    }while(had_one);
+  }
+}
+
+/** Set back the timestamp of the last call to sys_check_timeouts()
+ * This is necessary if sys_check_timeouts() hasn't been called for a long
+ * time (e.g. while saving energy) to prevent all timer functions of that
+ * period being called.
+ */
+void
+sys_restart_timeouts(void)
+{
+  timeouts_last_time = sys_now();
+}
+
+#else /* NO_SYS */
+
+/**
+ * Wait (forever) for a message to arrive in an mbox.
+ * While waiting, timeouts are processed.
+ *
+ * @param mbox the mbox to fetch the message from
+ * @param msg the place to store the message
+ */
+void
+sys_timeouts_mbox_fetch(sys_mbox_t *mbox, void **msg)
+{
+  u32_t time_needed;
+  struct sys_timeo *tmptimeout;
+  sys_timeout_handler handler;
+  void *arg;
+
+ again:
+  if (!next_timeout) {
+    time_needed = sys_arch_mbox_fetch(mbox, msg, 0);
+  } else {
+    if (next_timeout->time > 0) {
+      time_needed = sys_arch_mbox_fetch(mbox, msg, next_timeout->time);
+    } else {
+      time_needed = SYS_ARCH_TIMEOUT;
+    }
+
+    if (time_needed == SYS_ARCH_TIMEOUT) {
+      /* If time == SYS_ARCH_TIMEOUT, a timeout occured before a message
+         could be fetched. We should now call the timeout handler and
+         deallocate the memory allocated for the timeout. */
+      tmptimeout = next_timeout;
+      next_timeout = tmptimeout->next;
+      handler = tmptimeout->h;
+      arg = tmptimeout->arg;
+#if LWIP_DEBUG_TIMERNAMES
+      if (handler != NULL) {
+        LWIP_DEBUGF(TIMERS_DEBUG, ("stmf calling h=%s arg=%p\n",
+          tmptimeout->handler_name, arg));
+      }
+#endif /* LWIP_DEBUG_TIMERNAMES */
+      memp_free(MEMP_SYS_TIMEOUT, tmptimeout);
+      if (handler != NULL) {
+        /* For LWIP_TCPIP_CORE_LOCKING, lock the core before calling the
+           timeout handler function. */
+        LOCK_TCPIP_CORE();
+        handler(arg);
+        UNLOCK_TCPIP_CORE();
+      }
+      LWIP_TCPIP_THREAD_ALIVE();
+
+      /* We try again to fetch a message from the mbox. */
+      goto again;
+    } else {
+      /* If time != SYS_ARCH_TIMEOUT, a message was received before the timeout
+         occured. The time variable is set to the number of
+         milliseconds we waited for the message. */
+      if (time_needed < next_timeout->time) {
+        next_timeout->time -= time_needed;
+      } else {
+        next_timeout->time = 0;
+      }
+    }
+  }
+}
+
+#endif /* NO_SYS */
+
+#else /* LWIP_TIMERS */
+/* Satisfy the TCP code which calls this function */
+void
+tcp_timer_needed(void)
+{
+}
+#endif /* LWIP_TIMERS */
diff --git a/core/lwip/src/core/udp.c b/core/lwip/src/core/udp.c
new file mode 100644
index 00000000..4596ba2b
--- /dev/null
+++ b/core/lwip/src/core/udp.c
@@ -0,0 +1,966 @@
+/**
+ * @file
+ * User Datagram Protocol module
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+
+/* udp.c
+ *
+ * The code for the User Datagram Protocol UDP & UDPLite (RFC 3828).
+ *
+ */
+
+/* @todo Check the use of '(struct udp_pcb).chksum_len_rx'!
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_UDP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/udp.h"
+#include "lwip/def.h"
+#include "lwip/memp.h"
+#include "lwip/inet_chksum.h"
+#include "lwip/ip_addr.h"
+#include "lwip/netif.h"
+#include "lwip/icmp.h"
+#include "lwip/stats.h"
+#include "lwip/snmp.h"
+#include "arch/perf.h"
+#include "lwip/dhcp.h"
+
+#include <string.h>
+
+/* The list of UDP PCBs */
+/* exported in udp.h (was static) */
+struct udp_pcb *udp_pcbs;
+
+/**
+ * Process an incoming UDP datagram.
+ *
+ * Given an incoming UDP datagram (as a chain of pbufs) this function
+ * finds a corresponding UDP PCB and hands over the pbuf to the pcbs
+ * recv function. If no pcb is found or the datagram is incorrect, the
+ * pbuf is freed.
+ *
+ * @param p pbuf to be demultiplexed to a UDP PCB.
+ * @param inp network interface on which the datagram was received.
+ *
+ */
+void
+udp_input(struct pbuf *p, struct netif *inp)
+{
+  struct udp_hdr *udphdr;
+  struct udp_pcb *pcb, *prev;
+  struct udp_pcb *uncon_pcb;
+  struct ip_hdr *iphdr;
+  u16_t src, dest;
+  u8_t local_match;
+  u8_t broadcast;
+
+  PERF_START;
+
+  UDP_STATS_INC(udp.recv);
+
+  iphdr = (struct ip_hdr *)p->payload;
+
+  /* Check minimum length (IP header + UDP header)
+   * and move payload pointer to UDP header */
+  if (p->tot_len < (IPH_HL(iphdr) * 4 + UDP_HLEN) || pbuf_header(p, -(s16_t)(IPH_HL(iphdr) * 4))) {
+    /* drop short packets */
+    LWIP_DEBUGF(UDP_DEBUG,
+                ("udp_input: short UDP datagram (%"U16_F" bytes) discarded\n", p->tot_len));
+    UDP_STATS_INC(udp.lenerr);
+    UDP_STATS_INC(udp.drop);
+    snmp_inc_udpinerrors();
+    pbuf_free(p);
+    goto end;
+  }
+
+  udphdr = (struct udp_hdr *)p->payload;
+
+  /* is broadcast packet ? */
+  broadcast = ip_addr_isbroadcast(&current_iphdr_dest, inp);
+
+  LWIP_DEBUGF(UDP_DEBUG, ("udp_input: received datagram of length %"U16_F"\n", p->tot_len));
+
+  /* convert src and dest ports to host byte order */
+  src = ntohs(udphdr->src);
+  dest = ntohs(udphdr->dest);
+
+  udp_debug_print(udphdr);
+
+  /* print the UDP source and destination */
+  LWIP_DEBUGF(UDP_DEBUG,
+              ("udp (%"U16_F".%"U16_F".%"U16_F".%"U16_F", %"U16_F") <-- "
+               "(%"U16_F".%"U16_F".%"U16_F".%"U16_F", %"U16_F")\n",
+               ip4_addr1_16(&iphdr->dest), ip4_addr2_16(&iphdr->dest),
+               ip4_addr3_16(&iphdr->dest), ip4_addr4_16(&iphdr->dest), ntohs(udphdr->dest),
+               ip4_addr1_16(&iphdr->src), ip4_addr2_16(&iphdr->src),
+               ip4_addr3_16(&iphdr->src), ip4_addr4_16(&iphdr->src), ntohs(udphdr->src)));
+
+#if LWIP_DHCP
+  pcb = NULL;
+  /* when LWIP_DHCP is active, packets to DHCP_CLIENT_PORT may only be processed by
+     the dhcp module, no other UDP pcb may use the local UDP port DHCP_CLIENT_PORT */
+  if (dest == DHCP_CLIENT_PORT) {
+    /* all packets for DHCP_CLIENT_PORT not coming from DHCP_SERVER_PORT are dropped! */
+    if (src == DHCP_SERVER_PORT) {
+      if ((inp->dhcp != NULL) && (inp->dhcp->pcb != NULL)) {
+        /* accept the packe if 
+           (- broadcast or directed to us) -> DHCP is link-layer-addressed, local ip is always ANY!
+           - inp->dhcp->pcb->remote == ANY or iphdr->src */
+        if ((ip_addr_isany(&inp->dhcp->pcb->remote_ip) ||
+           ip_addr_cmp(&(inp->dhcp->pcb->remote_ip), &current_iphdr_src))) {
+          pcb = inp->dhcp->pcb;
+        }
+      }
+    }
+  } else
+#endif /* LWIP_DHCP */
+  {
+    prev = NULL;
+    local_match = 0;
+    uncon_pcb = NULL;
+    /* Iterate through the UDP pcb list for a matching pcb.
+     * 'Perfect match' pcbs (connected to the remote port & ip address) are
+     * preferred. If no perfect match is found, the first unconnected pcb that
+     * matches the local port and ip address gets the datagram. */
+    for (pcb = udp_pcbs; pcb != NULL; pcb = pcb->next) {
+      local_match = 0;
+      /* print the PCB local and remote address */
+      LWIP_DEBUGF(UDP_DEBUG,
+                  ("pcb (%"U16_F".%"U16_F".%"U16_F".%"U16_F", %"U16_F") --- "
+                   "(%"U16_F".%"U16_F".%"U16_F".%"U16_F", %"U16_F")\n",
+                   ip4_addr1_16(&pcb->local_ip), ip4_addr2_16(&pcb->local_ip),
+                   ip4_addr3_16(&pcb->local_ip), ip4_addr4_16(&pcb->local_ip), pcb->local_port,
+                   ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip),
+                   ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip), pcb->remote_port));
+
+      /* compare PCB local addr+port to UDP destination addr+port */
+      if ((pcb->local_port == dest) &&
+          ((!broadcast && ip_addr_isany(&pcb->local_ip)) ||
+           ip_addr_cmp(&(pcb->local_ip), &current_iphdr_dest) ||
+#if LWIP_IGMP
+           ip_addr_ismulticast(&current_iphdr_dest) ||
+#endif /* LWIP_IGMP */
+#if IP_SOF_BROADCAST_RECV
+           (broadcast && (pcb->so_options & SOF_BROADCAST)))) {
+#else  /* IP_SOF_BROADCAST_RECV */
+           (broadcast))) {
+#endif /* IP_SOF_BROADCAST_RECV */
+        local_match = 1;
+        if ((uncon_pcb == NULL) && 
+            ((pcb->flags & UDP_FLAGS_CONNECTED) == 0)) {
+          /* the first unconnected matching PCB */
+          uncon_pcb = pcb;
+        }
+      }
+      /* compare PCB remote addr+port to UDP source addr+port */
+      if ((local_match != 0) &&
+          (pcb->remote_port == src) &&
+          (ip_addr_isany(&pcb->remote_ip) ||
+           ip_addr_cmp(&(pcb->remote_ip), &current_iphdr_src))) {
+        /* the first fully matching PCB */
+        if (prev != NULL) {
+          /* move the pcb to the front of udp_pcbs so that is
+             found faster next time */
+          prev->next = pcb->next;
+          pcb->next = udp_pcbs;
+          udp_pcbs = pcb;
+        } else {
+          UDP_STATS_INC(udp.cachehit);
+        }
+        break;
+      }
+      prev = pcb;
+    }
+    /* no fully matching pcb found? then look for an unconnected pcb */
+    if (pcb == NULL) {
+      pcb = uncon_pcb;
+    }
+  }
+
+  /* Check checksum if this is a match or if it was directed at us. */
+  if (pcb != NULL || ip_addr_cmp(&inp->ip_addr, &current_iphdr_dest)) {
+    LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_input: calculating checksum\n"));
+#if LWIP_UDPLITE
+    if (IPH_PROTO(iphdr) == IP_PROTO_UDPLITE) {
+      /* Do the UDP Lite checksum */
+#if CHECKSUM_CHECK_UDP
+      u16_t chklen = ntohs(udphdr->len);
+      if (chklen < sizeof(struct udp_hdr)) {
+        if (chklen == 0) {
+          /* For UDP-Lite, checksum length of 0 means checksum
+             over the complete packet (See RFC 3828 chap. 3.1) */
+          chklen = p->tot_len;
+        } else {
+          /* At least the UDP-Lite header must be covered by the
+             checksum! (Again, see RFC 3828 chap. 3.1) */
+          UDP_STATS_INC(udp.chkerr);
+          UDP_STATS_INC(udp.drop);
+          snmp_inc_udpinerrors();
+          pbuf_free(p);
+          goto end;
+        }
+      }
+      if (inet_chksum_pseudo_partial(p, &current_iphdr_src, &current_iphdr_dest,
+                             IP_PROTO_UDPLITE, p->tot_len, chklen) != 0) {
+       LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
+                   ("udp_input: UDP Lite datagram discarded due to failing checksum\n"));
+        UDP_STATS_INC(udp.chkerr);
+        UDP_STATS_INC(udp.drop);
+        snmp_inc_udpinerrors();
+        pbuf_free(p);
+        goto end;
+      }
+#endif /* CHECKSUM_CHECK_UDP */
+    } else
+#endif /* LWIP_UDPLITE */
+    {
+#if CHECKSUM_CHECK_UDP
+      if (udphdr->chksum != 0) {
+        if (inet_chksum_pseudo(p, ip_current_src_addr(), ip_current_dest_addr(),
+                               IP_PROTO_UDP, p->tot_len) != 0) {
+          LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
+                      ("udp_input: UDP datagram discarded due to failing checksum\n"));
+          UDP_STATS_INC(udp.chkerr);
+          UDP_STATS_INC(udp.drop);
+          snmp_inc_udpinerrors();
+          pbuf_free(p);
+          goto end;
+        }
+      }
+#endif /* CHECKSUM_CHECK_UDP */
+    }
+    if(pbuf_header(p, -UDP_HLEN)) {
+      /* Can we cope with this failing? Just assert for now */
+      LWIP_ASSERT("pbuf_header failed\n", 0);
+      UDP_STATS_INC(udp.drop);
+      snmp_inc_udpinerrors();
+      pbuf_free(p);
+      goto end;
+    }
+    if (pcb != NULL) {
+      snmp_inc_udpindatagrams();
+#if SO_REUSE && SO_REUSE_RXTOALL
+      if ((broadcast || ip_addr_ismulticast(&current_iphdr_dest)) &&
+          ((pcb->so_options & SOF_REUSEADDR) != 0)) {
+        /* pass broadcast- or multicast packets to all multicast pcbs
+           if SOF_REUSEADDR is set on the first match */
+        struct udp_pcb *mpcb;
+        u8_t p_header_changed = 0;
+        for (mpcb = udp_pcbs; mpcb != NULL; mpcb = mpcb->next) {
+          if (mpcb != pcb) {
+            /* compare PCB local addr+port to UDP destination addr+port */
+            if ((mpcb->local_port == dest) &&
+                ((!broadcast && ip_addr_isany(&mpcb->local_ip)) ||
+                 ip_addr_cmp(&(mpcb->local_ip), &current_iphdr_dest) ||
+#if LWIP_IGMP
+                 ip_addr_ismulticast(&current_iphdr_dest) ||
+#endif /* LWIP_IGMP */
+#if IP_SOF_BROADCAST_RECV
+                 (broadcast && (mpcb->so_options & SOF_BROADCAST)))) {
+#else  /* IP_SOF_BROADCAST_RECV */
+                 (broadcast))) {
+#endif /* IP_SOF_BROADCAST_RECV */
+              /* pass a copy of the packet to all local matches */
+              if (mpcb->recv != NULL) {
+                struct pbuf *q;
+                /* for that, move payload to IP header again */
+                if (p_header_changed == 0) {
+                  pbuf_header(p, (s16_t)((IPH_HL(iphdr) * 4) + UDP_HLEN));
+                  p_header_changed = 1;
+                }
+                q = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_RAM);
+                if (q != NULL) {
+                  err_t err = pbuf_copy(q, p);
+                  if (err == ERR_OK) {
+                    /* move payload to UDP data */
+                    pbuf_header(q, -(s16_t)((IPH_HL(iphdr) * 4) + UDP_HLEN));
+                    mpcb->recv(mpcb->recv_arg, mpcb, q, ip_current_src_addr(), src);
+                  }
+                }
+              }
+            }
+          }
+        }
+        if (p_header_changed) {
+          /* and move payload to UDP data again */
+          pbuf_header(p, -(s16_t)((IPH_HL(iphdr) * 4) + UDP_HLEN));
+        }
+      }
+#endif /* SO_REUSE && SO_REUSE_RXTOALL */
+      /* callback */
+      if (pcb->recv != NULL) {
+        /* now the recv function is responsible for freeing p */
+        pcb->recv(pcb->recv_arg, pcb, p, ip_current_src_addr(), src);
+      } else {
+        /* no recv function registered? then we have to free the pbuf! */
+        pbuf_free(p);
+        goto end;
+      }
+    } else {
+      LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_input: not for us.\n"));
+
+#if LWIP_ICMP
+      /* No match was found, send ICMP destination port unreachable unless
+         destination address was broadcast/multicast. */
+      if (!broadcast &&
+          !ip_addr_ismulticast(&current_iphdr_dest)) {
+        /* move payload pointer back to ip header */
+        pbuf_header(p, (IPH_HL(iphdr) * 4) + UDP_HLEN);
+        LWIP_ASSERT("p->payload == iphdr", (p->payload == iphdr));
+        icmp_dest_unreach(p, ICMP_DUR_PORT);
+      }
+#endif /* LWIP_ICMP */
+      UDP_STATS_INC(udp.proterr);
+      UDP_STATS_INC(udp.drop);
+      snmp_inc_udpnoports();
+      pbuf_free(p);
+    }
+  } else {
+    pbuf_free(p);
+  }
+end:
+  PERF_STOP("udp_input");
+}
+
+/**
+ * Send data using UDP.
+ *
+ * @param pcb UDP PCB used to send the data.
+ * @param p chain of pbuf's to be sent.
+ *
+ * The datagram will be sent to the current remote_ip & remote_port
+ * stored in pcb. If the pcb is not bound to a port, it will
+ * automatically be bound to a random port.
+ *
+ * @return lwIP error code.
+ * - ERR_OK. Successful. No error occured.
+ * - ERR_MEM. Out of memory.
+ * - ERR_RTE. Could not find route to destination address.
+ * - More errors could be returned by lower protocol layers.
+ *
+ * @see udp_disconnect() udp_sendto()
+ */
+err_t
+udp_send(struct udp_pcb *pcb, struct pbuf *p)
+{
+  /* send to the packet using remote ip and port stored in the pcb */
+  return udp_sendto(pcb, p, &pcb->remote_ip, pcb->remote_port);
+}
+
+#if LWIP_CHECKSUM_ON_COPY
+/** Same as udp_send() but with checksum
+ */
+err_t
+udp_send_chksum(struct udp_pcb *pcb, struct pbuf *p,
+                u8_t have_chksum, u16_t chksum)
+{
+  /* send to the packet using remote ip and port stored in the pcb */
+  return udp_sendto_chksum(pcb, p, &pcb->remote_ip, pcb->remote_port,
+    have_chksum, chksum);
+}
+#endif /* LWIP_CHECKSUM_ON_COPY */
+
+/**
+ * Send data to a specified address using UDP.
+ *
+ * @param pcb UDP PCB used to send the data.
+ * @param p chain of pbuf's to be sent.
+ * @param dst_ip Destination IP address.
+ * @param dst_port Destination UDP port.
+ *
+ * dst_ip & dst_port are expected to be in the same byte order as in the pcb.
+ *
+ * If the PCB already has a remote address association, it will
+ * be restored after the data is sent.
+ * 
+ * @return lwIP error code (@see udp_send for possible error codes)
+ *
+ * @see udp_disconnect() udp_send()
+ */
+err_t
+udp_sendto(struct udp_pcb *pcb, struct pbuf *p,
+  ip_addr_t *dst_ip, u16_t dst_port)
+{
+#if LWIP_CHECKSUM_ON_COPY
+  return udp_sendto_chksum(pcb, p, dst_ip, dst_port, 0, 0);
+}
+
+/** Same as udp_sendto(), but with checksum */
+err_t
+udp_sendto_chksum(struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *dst_ip,
+                  u16_t dst_port, u8_t have_chksum, u16_t chksum)
+{
+#endif /* LWIP_CHECKSUM_ON_COPY */
+  struct netif *netif;
+
+  LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_send\n"));
+
+  /* find the outgoing network interface for this packet */
+#if LWIP_IGMP
+  netif = ip_route((ip_addr_ismulticast(dst_ip))?(&(pcb->multicast_ip)):(dst_ip));
+#else
+  netif = ip_route(dst_ip);
+#endif /* LWIP_IGMP */
+
+  /* no outgoing network interface could be found? */
+  if (netif == NULL) {
+    LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("udp_send: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+      ip4_addr1_16(dst_ip), ip4_addr2_16(dst_ip), ip4_addr3_16(dst_ip), ip4_addr4_16(dst_ip)));
+    UDP_STATS_INC(udp.rterr);
+    return ERR_RTE;
+  }
+#if LWIP_CHECKSUM_ON_COPY
+  return udp_sendto_if_chksum(pcb, p, dst_ip, dst_port, netif, have_chksum, chksum);
+#else /* LWIP_CHECKSUM_ON_COPY */
+  return udp_sendto_if(pcb, p, dst_ip, dst_port, netif);
+#endif /* LWIP_CHECKSUM_ON_COPY */
+}
+
+/**
+ * Send data to a specified address using UDP.
+ * The netif used for sending can be specified.
+ *
+ * This function exists mainly for DHCP, to be able to send UDP packets
+ * on a netif that is still down.
+ *
+ * @param pcb UDP PCB used to send the data.
+ * @param p chain of pbuf's to be sent.
+ * @param dst_ip Destination IP address.
+ * @param dst_port Destination UDP port.
+ * @param netif the netif used for sending.
+ *
+ * dst_ip & dst_port are expected to be in the same byte order as in the pcb.
+ *
+ * @return lwIP error code (@see udp_send for possible error codes)
+ *
+ * @see udp_disconnect() udp_send()
+ */
+err_t
+udp_sendto_if(struct udp_pcb *pcb, struct pbuf *p,
+  ip_addr_t *dst_ip, u16_t dst_port, struct netif *netif)
+{
+#if LWIP_CHECKSUM_ON_COPY
+  return udp_sendto_if_chksum(pcb, p, dst_ip, dst_port, netif, 0, 0);
+}
+
+/** Same as udp_sendto_if(), but with checksum */
+err_t
+udp_sendto_if_chksum(struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *dst_ip,
+                     u16_t dst_port, struct netif *netif, u8_t have_chksum,
+                     u16_t chksum)
+{
+#endif /* LWIP_CHECKSUM_ON_COPY */
+  struct udp_hdr *udphdr;
+  ip_addr_t *src_ip;
+  err_t err;
+  struct pbuf *q; /* q will be sent down the stack */
+
+#if IP_SOF_BROADCAST
+  /* broadcast filter? */
+  if ( ((pcb->so_options & SOF_BROADCAST) == 0) && ip_addr_isbroadcast(dst_ip, netif) ) {
+    LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
+      ("udp_sendto_if: SOF_BROADCAST not enabled on pcb %p\n", (void *)pcb));
+    return ERR_VAL;
+  }
+#endif /* IP_SOF_BROADCAST */
+
+  /* if the PCB is not yet bound to a port, bind it here */
+  if (pcb->local_port == 0) {
+    LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_send: not yet bound to a port, binding now\n"));
+    err = udp_bind(pcb, &pcb->local_ip, pcb->local_port);
+    if (err != ERR_OK) {
+      LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("udp_send: forced port bind failed\n"));
+      return err;
+    }
+  }
+
+  /* not enough space to add an UDP header to first pbuf in given p chain? */
+  if (pbuf_header(p, UDP_HLEN)) {
+    /* allocate header in a separate new pbuf */
+    q = pbuf_alloc(PBUF_IP, UDP_HLEN, PBUF_RAM);
+    /* new header pbuf could not be allocated? */
+    if (q == NULL) {
+      LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("udp_send: could not allocate header\n"));
+      return ERR_MEM;
+    }
+    if (p->tot_len != 0) {
+      /* chain header q in front of given pbuf p (only if p contains data) */
+      pbuf_chain(q, p);
+    }
+    /* first pbuf q points to header pbuf */
+    LWIP_DEBUGF(UDP_DEBUG,
+                ("udp_send: added header pbuf %p before given pbuf %p\n", (void *)q, (void *)p));
+  } else {
+    /* adding space for header within p succeeded */
+    /* first pbuf q equals given pbuf */
+    q = p;
+    LWIP_DEBUGF(UDP_DEBUG, ("udp_send: added header in given pbuf %p\n", (void *)p));
+  }
+  LWIP_ASSERT("check that first pbuf can hold struct udp_hdr",
+              (q->len >= sizeof(struct udp_hdr)));
+  /* q now represents the packet to be sent */
+  udphdr = (struct udp_hdr *)q->payload;
+  udphdr->src = htons(pcb->local_port);
+  udphdr->dest = htons(dst_port);
+  /* in UDP, 0 checksum means 'no checksum' */
+  udphdr->chksum = 0x0000; 
+
+  /* Multicast Loop? */
+#if LWIP_IGMP
+  if (ip_addr_ismulticast(dst_ip) && ((pcb->flags & UDP_FLAGS_MULTICAST_LOOP) != 0)) {
+    q->flags |= PBUF_FLAG_MCASTLOOP;
+  }
+#endif /* LWIP_IGMP */
+
+
+  /* PCB local address is IP_ANY_ADDR? */
+  if (ip_addr_isany(&pcb->local_ip)) {
+    /* use outgoing network interface IP address as source address */
+    src_ip = &(netif->ip_addr);
+  } else {
+    /* check if UDP PCB local IP address is correct
+     * this could be an old address if netif->ip_addr has changed */
+    if (!ip_addr_cmp(&(pcb->local_ip), &(netif->ip_addr))) {
+      /* local_ip doesn't match, drop the packet */
+      if (q != p) {
+        /* free the header pbuf */
+        pbuf_free(q);
+        q = NULL;
+        /* p is still referenced by the caller, and will live on */
+      }
+      return ERR_VAL;
+    }
+    /* use UDP PCB local IP address as source address */
+    src_ip = &(pcb->local_ip);
+  }
+
+  LWIP_DEBUGF(UDP_DEBUG, ("udp_send: sending datagram of length %"U16_F"\n", q->tot_len));
+
+#if LWIP_UDPLITE
+  /* UDP Lite protocol? */
+  if (pcb->flags & UDP_FLAGS_UDPLITE) {
+    u16_t chklen, chklen_hdr;
+    LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP LITE packet length %"U16_F"\n", q->tot_len));
+    /* set UDP message length in UDP header */
+    chklen_hdr = chklen = pcb->chksum_len_tx;
+    if ((chklen < sizeof(struct udp_hdr)) || (chklen > q->tot_len)) {
+      if (chklen != 0) {
+        LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP LITE pcb->chksum_len is illegal: %"U16_F"\n", chklen));
+      }
+      /* For UDP-Lite, checksum length of 0 means checksum
+         over the complete packet. (See RFC 3828 chap. 3.1)
+         At least the UDP-Lite header must be covered by the
+         checksum, therefore, if chksum_len has an illegal
+         value, we generate the checksum over the complete
+         packet to be safe. */
+      chklen_hdr = 0;
+      chklen = q->tot_len;
+    }
+    udphdr->len = htons(chklen_hdr);
+    /* calculate checksum */
+#if CHECKSUM_GEN_UDP
+    udphdr->chksum = inet_chksum_pseudo_partial(q, src_ip, dst_ip,
+      IP_PROTO_UDPLITE, q->tot_len,
+#if !LWIP_CHECKSUM_ON_COPY
+      chklen);
+#else /* !LWIP_CHECKSUM_ON_COPY */
+      (have_chksum ? UDP_HLEN : chklen));
+    if (have_chksum) {
+      u32_t acc;
+      acc = udphdr->chksum + (u16_t)~(chksum);
+      udphdr->chksum = FOLD_U32T(acc);
+    }
+#endif /* !LWIP_CHECKSUM_ON_COPY */
+
+    /* chksum zero must become 0xffff, as zero means 'no checksum' */
+    if (udphdr->chksum == 0x0000) {
+      udphdr->chksum = 0xffff;
+    }
+#endif /* CHECKSUM_GEN_UDP */
+    /* output to IP */
+    LWIP_DEBUGF(UDP_DEBUG, ("udp_send: ip_output_if (,,,,IP_PROTO_UDPLITE,)\n"));
+#if LWIP_NETIF_HWADDRHINT
+    netif->addr_hint = &(pcb->addr_hint);
+#endif /* LWIP_NETIF_HWADDRHINT*/
+    err = ip_output_if(q, src_ip, dst_ip, pcb->ttl, pcb->tos, IP_PROTO_UDPLITE, netif);
+#if LWIP_NETIF_HWADDRHINT
+    netif->addr_hint = NULL;
+#endif /* LWIP_NETIF_HWADDRHINT*/
+  } else
+#endif /* LWIP_UDPLITE */
+  {      /* UDP */
+    LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP packet length %"U16_F"\n", q->tot_len));
+    udphdr->len = htons(q->tot_len);
+    /* calculate checksum */
+#if CHECKSUM_GEN_UDP
+    if ((pcb->flags & UDP_FLAGS_NOCHKSUM) == 0) {
+      u16_t udpchksum;
+#if LWIP_CHECKSUM_ON_COPY
+      if (have_chksum) {
+        u32_t acc;
+        udpchksum = inet_chksum_pseudo_partial(q, src_ip, dst_ip, IP_PROTO_UDP,
+          q->tot_len, UDP_HLEN);
+        acc = udpchksum + (u16_t)~(chksum);
+        udpchksum = FOLD_U32T(acc);
+      } else
+#endif /* LWIP_CHECKSUM_ON_COPY */
+      {
+        udpchksum = inet_chksum_pseudo(q, src_ip, dst_ip, IP_PROTO_UDP, q->tot_len);
+      }
+
+      /* chksum zero must become 0xffff, as zero means 'no checksum' */
+      if (udpchksum == 0x0000) {
+        udpchksum = 0xffff;
+      }
+      udphdr->chksum = udpchksum;
+    }
+#endif /* CHECKSUM_GEN_UDP */
+    LWIP_DEBUGF(UDP_DEBUG, ("udp_send: UDP checksum 0x%04"X16_F"\n", udphdr->chksum));
+    LWIP_DEBUGF(UDP_DEBUG, ("udp_send: ip_output_if (,,,,IP_PROTO_UDP,)\n"));
+    /* output to IP */
+#if LWIP_NETIF_HWADDRHINT
+    netif->addr_hint = &(pcb->addr_hint);
+#endif /* LWIP_NETIF_HWADDRHINT*/
+    err = ip_output_if(q, src_ip, dst_ip, pcb->ttl, pcb->tos, IP_PROTO_UDP, netif);
+#if LWIP_NETIF_HWADDRHINT
+    netif->addr_hint = NULL;
+#endif /* LWIP_NETIF_HWADDRHINT*/
+  }
+  /* TODO: must this be increased even if error occured? */
+  snmp_inc_udpoutdatagrams();
+
+  /* did we chain a separate header pbuf earlier? */
+  if (q != p) {
+    /* free the header pbuf */
+    pbuf_free(q);
+    q = NULL;
+    /* p is still referenced by the caller, and will live on */
+  }
+
+  UDP_STATS_INC(udp.xmit);
+  return err;
+}
+
+/**
+ * Bind an UDP PCB.
+ *
+ * @param pcb UDP PCB to be bound with a local address ipaddr and port.
+ * @param ipaddr local IP address to bind with. Use IP_ADDR_ANY to
+ * bind to all local interfaces.
+ * @param port local UDP port to bind with. Use 0 to automatically bind
+ * to a random port between UDP_LOCAL_PORT_RANGE_START and
+ * UDP_LOCAL_PORT_RANGE_END.
+ *
+ * ipaddr & port are expected to be in the same byte order as in the pcb.
+ *
+ * @return lwIP error code.
+ * - ERR_OK. Successful. No error occured.
+ * - ERR_USE. The specified ipaddr and port are already bound to by
+ * another UDP PCB.
+ *
+ * @see udp_disconnect()
+ */
+err_t
+udp_bind(struct udp_pcb *pcb, ip_addr_t *ipaddr, u16_t port)
+{
+  struct udp_pcb *ipcb;
+  u8_t rebind;
+
+  LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, ("udp_bind(ipaddr = "));
+  ip_addr_debug_print(UDP_DEBUG, ipaddr);
+  LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE, (", port = %"U16_F")\n", port));
+
+  rebind = 0;
+  /* Check for double bind and rebind of the same pcb */
+  for (ipcb = udp_pcbs; ipcb != NULL; ipcb = ipcb->next) {
+    /* is this UDP PCB already on active list? */
+    if (pcb == ipcb) {
+      /* pcb may occur at most once in active list */
+      LWIP_ASSERT("rebind == 0", rebind == 0);
+      /* pcb already in list, just rebind */
+      rebind = 1;
+    }
+
+    /* By default, we don't allow to bind to a port that any other udp
+       PCB is alread bound to, unless *all* PCBs with that port have tha
+       REUSEADDR flag set. */
+#if SO_REUSE
+    else if (((pcb->so_options & SOF_REUSEADDR) == 0) &&
+             ((ipcb->so_options & SOF_REUSEADDR) == 0)) {
+#else /* SO_REUSE */
+    /* port matches that of PCB in list and REUSEADDR not set -> reject */
+    else {
+#endif /* SO_REUSE */
+      if ((ipcb->local_port == port) &&
+          /* IP address matches, or one is IP_ADDR_ANY? */
+          (ip_addr_isany(&(ipcb->local_ip)) ||
+           ip_addr_isany(ipaddr) ||
+           ip_addr_cmp(&(ipcb->local_ip), ipaddr))) {
+        /* other PCB already binds to this local IP and port */
+        LWIP_DEBUGF(UDP_DEBUG,
+                    ("udp_bind: local port %"U16_F" already bound by another pcb\n", port));
+        return ERR_USE;
+      }
+    }
+  }
+
+  ip_addr_set(&pcb->local_ip, ipaddr);
+
+  /* no port specified? */
+  if (port == 0) {
+#ifndef UDP_LOCAL_PORT_RANGE_START
+/* From http://www.iana.org/assignments/port-numbers:
+   "The Dynamic and/or Private Ports are those from 49152 through 65535" */
+#define UDP_LOCAL_PORT_RANGE_START  0xc000
+#define UDP_LOCAL_PORT_RANGE_END    0xffff
+#endif
+    port = UDP_LOCAL_PORT_RANGE_START;
+    ipcb = udp_pcbs;
+    while ((ipcb != NULL) && (port != UDP_LOCAL_PORT_RANGE_END)) {
+      if (ipcb->local_port == port) {
+        /* port is already used by another udp_pcb */
+        port++;
+        /* restart scanning all udp pcbs */
+        ipcb = udp_pcbs;
+      } else {
+        /* go on with next udp pcb */
+        ipcb = ipcb->next;
+      }
+    }
+    if (ipcb != NULL) {
+      /* no more ports available in local range */
+      LWIP_DEBUGF(UDP_DEBUG, ("udp_bind: out of free UDP ports\n"));
+      return ERR_USE;
+    }
+  }
+  pcb->local_port = port;
+  snmp_insert_udpidx_tree(pcb);
+  /* pcb not active yet? */
+  if (rebind == 0) {
+    /* place the PCB on the active list if not already there */
+    pcb->next = udp_pcbs;
+    udp_pcbs = pcb;
+  }
+  LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+              ("udp_bind: bound to %"U16_F".%"U16_F".%"U16_F".%"U16_F", port %"U16_F"\n",
+               ip4_addr1_16(&pcb->local_ip), ip4_addr2_16(&pcb->local_ip),
+               ip4_addr3_16(&pcb->local_ip), ip4_addr4_16(&pcb->local_ip),
+               pcb->local_port));
+  return ERR_OK;
+}
+/**
+ * Connect an UDP PCB.
+ *
+ * This will associate the UDP PCB with the remote address.
+ *
+ * @param pcb UDP PCB to be connected with remote address ipaddr and port.
+ * @param ipaddr remote IP address to connect with.
+ * @param port remote UDP port to connect with.
+ *
+ * @return lwIP error code
+ *
+ * ipaddr & port are expected to be in the same byte order as in the pcb.
+ *
+ * The udp pcb is bound to a random local port if not already bound.
+ *
+ * @see udp_disconnect()
+ */
+err_t
+udp_connect(struct udp_pcb *pcb, ip_addr_t *ipaddr, u16_t port)
+{
+  struct udp_pcb *ipcb;
+
+  if (pcb->local_port == 0) {
+    err_t err = udp_bind(pcb, &pcb->local_ip, pcb->local_port);
+    if (err != ERR_OK) {
+      return err;
+    }
+  }
+
+  ip_addr_set(&pcb->remote_ip, ipaddr);
+  pcb->remote_port = port;
+  pcb->flags |= UDP_FLAGS_CONNECTED;
+/** TODO: this functionality belongs in upper layers */
+#ifdef LWIP_UDP_TODO
+  /* Nail down local IP for netconn_addr()/getsockname() */
+  if (ip_addr_isany(&pcb->local_ip) && !ip_addr_isany(&pcb->remote_ip)) {
+    struct netif *netif;
+
+    if ((netif = ip_route(&(pcb->remote_ip))) == NULL) {
+      LWIP_DEBUGF(UDP_DEBUG, ("udp_connect: No route to 0x%lx\n", pcb->remote_ip.addr));
+      UDP_STATS_INC(udp.rterr);
+      return ERR_RTE;
+    }
+    /** TODO: this will bind the udp pcb locally, to the interface which
+        is used to route output packets to the remote address. However, we
+        might want to accept incoming packets on any interface! */
+    pcb->local_ip = netif->ip_addr;
+  } else if (ip_addr_isany(&pcb->remote_ip)) {
+    pcb->local_ip.addr = 0;
+  }
+#endif
+  LWIP_DEBUGF(UDP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+              ("udp_connect: connected to %"U16_F".%"U16_F".%"U16_F".%"U16_F",port %"U16_F"\n",
+               ip4_addr1_16(&pcb->local_ip), ip4_addr2_16(&pcb->local_ip),
+               ip4_addr3_16(&pcb->local_ip), ip4_addr4_16(&pcb->local_ip),
+               pcb->local_port));
+
+  /* Insert UDP PCB into the list of active UDP PCBs. */
+  for (ipcb = udp_pcbs; ipcb != NULL; ipcb = ipcb->next) {
+    if (pcb == ipcb) {
+      /* already on the list, just return */
+      return ERR_OK;
+    }
+  }
+  /* PCB not yet on the list, add PCB now */
+  pcb->next = udp_pcbs;
+  udp_pcbs = pcb;
+  return ERR_OK;
+}
+
+/**
+ * Disconnect a UDP PCB
+ *
+ * @param pcb the udp pcb to disconnect.
+ */
+void
+udp_disconnect(struct udp_pcb *pcb)
+{
+  /* reset remote address association */
+  ip_addr_set_any(&pcb->remote_ip);
+  pcb->remote_port = 0;
+  /* mark PCB as unconnected */
+  pcb->flags &= ~UDP_FLAGS_CONNECTED;
+}
+
+/**
+ * Set a receive callback for a UDP PCB
+ *
+ * This callback will be called when receiving a datagram for the pcb.
+ *
+ * @param pcb the pcb for wich to set the recv callback
+ * @param recv function pointer of the callback function
+ * @param recv_arg additional argument to pass to the callback function
+ */
+void
+udp_recv(struct udp_pcb *pcb, udp_recv_fn recv, void *recv_arg)
+{
+  /* remember recv() callback and user data */
+  pcb->recv = recv;
+  pcb->recv_arg = recv_arg;
+}
+
+/**
+ * Remove an UDP PCB.
+ *
+ * @param pcb UDP PCB to be removed. The PCB is removed from the list of
+ * UDP PCB's and the data structure is freed from memory.
+ *
+ * @see udp_new()
+ */
+void
+udp_remove(struct udp_pcb *pcb)
+{
+  struct udp_pcb *pcb2;
+
+  snmp_delete_udpidx_tree(pcb);
+  /* pcb to be removed is first in list? */
+  if (udp_pcbs == pcb) {
+    /* make list start at 2nd pcb */
+    udp_pcbs = udp_pcbs->next;
+    /* pcb not 1st in list */
+  } else {
+    for (pcb2 = udp_pcbs; pcb2 != NULL; pcb2 = pcb2->next) {
+      /* find pcb in udp_pcbs list */
+      if (pcb2->next != NULL && pcb2->next == pcb) {
+        /* remove pcb from list */
+        pcb2->next = pcb->next;
+      }
+    }
+  }
+  memp_free(MEMP_UDP_PCB, pcb);
+}
+
+/**
+ * Create a UDP PCB.
+ *
+ * @return The UDP PCB which was created. NULL if the PCB data structure
+ * could not be allocated.
+ *
+ * @see udp_remove()
+ */
+struct udp_pcb *
+udp_new(void)
+{
+  struct udp_pcb *pcb;
+  pcb = (struct udp_pcb *)memp_malloc(MEMP_UDP_PCB);
+  /* could allocate UDP PCB? */
+  if (pcb != NULL) {
+    /* UDP Lite: by initializing to all zeroes, chksum_len is set to 0
+     * which means checksum is generated over the whole datagram per default
+     * (recommended as default by RFC 3828). */
+    /* initialize PCB to all zeroes */
+    memset(pcb, 0, sizeof(struct udp_pcb));
+    pcb->ttl = UDP_TTL;
+  }
+  return pcb;
+}
+
+#if UDP_DEBUG
+/**
+ * Print UDP header information for debug purposes.
+ *
+ * @param udphdr pointer to the udp header in memory.
+ */
+void
+udp_debug_print(struct udp_hdr *udphdr)
+{
+  LWIP_DEBUGF(UDP_DEBUG, ("UDP header:\n"));
+  LWIP_DEBUGF(UDP_DEBUG, ("+-------------------------------+\n"));
+  LWIP_DEBUGF(UDP_DEBUG, ("|     %5"U16_F"     |     %5"U16_F"     | (src port, dest port)\n",
+                          ntohs(udphdr->src), ntohs(udphdr->dest)));
+  LWIP_DEBUGF(UDP_DEBUG, ("+-------------------------------+\n"));
+  LWIP_DEBUGF(UDP_DEBUG, ("|     %5"U16_F"     |     0x%04"X16_F"    | (len, chksum)\n",
+                          ntohs(udphdr->len), ntohs(udphdr->chksum)));
+  LWIP_DEBUGF(UDP_DEBUG, ("+-------------------------------+\n"));
+}
+#endif /* UDP_DEBUG */
+
+#endif /* LWIP_UDP */
diff --git a/core/lwip/src/include/arch/cc.h b/core/lwip/src/include/arch/cc.h
new file mode 100644
index 00000000..677ef4f5
--- /dev/null
+++ b/core/lwip/src/include/arch/cc.h
@@ -0,0 +1,40 @@
+#ifndef __LWIP_ARCH_CC_H__
+#define __LWIP_ARCH_CC_H__
+
+#include <klibc/compiler.h>
+#include <inttypes.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <kaboom.h>
+#include <stdio.h>
+
+#define BYTE_ORDER LITTLE_ENDIAN
+
+typedef uint8_t  u8_t;
+typedef int8_t   s8_t;
+typedef uint16_t u16_t;
+typedef int16_t  s16_t;
+typedef uint32_t u32_t;
+typedef int32_t  s32_t;
+
+typedef uintptr_t mem_ptr_t;
+
+#define PACK_STRUCT_STRUCT	__packed
+
+#if 1
+#define LWIP_PLATFORM_DIAG(x)	do { printf x; } while(0)
+#define LWIP_PLATFORM_ASSERT(x)	do { printf("LWIP(%s,%d,%p): %s", __FILE__, __LINE__, __builtin_return_address(0), (x)); kaboom(); } while(0)
+#else
+#define LWIP_PLATFORM_DIAG(x)	((void)0) /* For now... */
+#define LWIP_PLATFORM_ASSERT(x)	kaboom()
+#endif
+
+#define U16_F	PRIu16
+#define S16_F	PRId16
+#define X16_F	PRIx16
+#define U32_F	PRIu16
+#define S32_F	PRId16
+#define X32_F	PRIx16
+#define SZT_F	"zu"
+
+#endif /* __LWIP_ARCH_CC_H__ */
diff --git a/core/lwip/src/include/arch/perf.h b/core/lwip/src/include/arch/perf.h
new file mode 100644
index 00000000..4ceb850c
--- /dev/null
+++ b/core/lwip/src/include/arch/perf.h
@@ -0,0 +1,7 @@
+#ifndef __LWIP_ARCH_PERF_H__
+#define __LWIP_ARCH_PERF_H__
+
+#define PERF_START
+#define PERF_STOP(x)
+
+#endif /* __LWIP_ARCH_PERF_H__ */
diff --git a/core/lwip/src/include/arch/sys_arch.h b/core/lwip/src/include/arch/sys_arch.h
new file mode 100644
index 00000000..732a19c4
--- /dev/null
+++ b/core/lwip/src/include/arch/sys_arch.h
@@ -0,0 +1,85 @@
+#ifndef __LWIP_ARCH_SYS_ARCH_H__
+#define __LWIP_ARCH_SYS_ARCH_H__
+
+#include <stddef.h>
+#include "arch/cc.h"
+#include <thread.h>
+#include <mbox.h>
+
+typedef struct semaphore *sys_sem_t;
+typedef struct mailbox   *sys_mbox_t;
+typedef struct thread    *sys_thread_t;
+
+static inline void sys_sem_signal(sys_sem_t *sem)
+{
+    if (!!sem)
+	sem_up(*sem);
+}
+
+#define sys_now ms_timer
+
+#define SYS_MBOX_NULL	NULL
+#define SYS_SEM_NULL	NULL
+
+extern void __compile_time_error(void);
+
+#define SYS_ARCH_OP(var, val, inc, add)					\
+do {									\
+    if (__builtin_constant_p(val) && (val) == 1) {			\
+	switch (sizeof(var)) {						\
+	case 1:								\
+	    asm volatile(inc "b %0" : "+m" (var));			\
+	    break;							\
+	case 2:								\
+	    asm volatile(inc "w %0" : "+m" (var));			\
+	    break;							\
+	case 4:								\
+	    asm volatile(inc "l %0" : "+m" (var));			\
+	    break;							\
+	default:							\
+	    __compile_time_error();					\
+	    break;							\
+	}								\
+    } else {								\
+	switch (sizeof(var)) {						\
+	case 1:								\
+	    asm volatile(add "b %1,%0" : "+m" (var) : "ri" (val));	\
+	    break;							\
+	case 2:								\
+	    asm volatile(add "w %1,%0" : "+m" (var) : "ri" (val));	\
+	    break;							\
+	case 4:								\
+	    asm volatile(add "l %1,%0" : "+m" (var) : "ri" (val));	\
+	    break;							\
+	default:							\
+	    __compile_time_error();					\
+	    break;							\
+	}								\
+    }									\
+} while (0)
+
+static inline struct sys_timeouts *sys_arch_timeouts(void)
+{
+    return (struct sys_timeouts *)&current()->pvt;
+}
+
+#define SYS_ARCH_INC(var, val) SYS_ARCH_OP(var, val, "inc", "add")
+#define SYS_ARCH_DEC(var, val) SYS_ARCH_OP(var, val, "dec", "sub")
+
+#define SYS_ARCH_GET(var, ret)					\
+    do {						 	\
+        volatile __typeof__(var) * const __varp = &(var);	\
+    	ret = *__varp;						\
+    } while (0)
+
+#define SYS_ARCH_SET(var, val)					\
+    do {						 	\
+        volatile __typeof__(var) * const __varp = &(var);	\
+    	*__varp = val;						\
+    } while (0)
+
+#define SYS_ARCH_DECL_PROTECT(VAR) irq_state_t VAR
+#define SYS_ARCH_PROTECT(VAR) VAR = irq_save()
+#define SYS_ARCH_UNPROTECT(VAR) irq_restore(VAR)
+
+#endif /* __LWIP_ARCH_SYS_ARCH_H__ */
diff --git a/core/lwip/src/include/ipv4/lwip/autoip.h b/core/lwip/src/include/ipv4/lwip/autoip.h
new file mode 100644
index 00000000..23c264a1
--- /dev/null
+++ b/core/lwip/src/include/ipv4/lwip/autoip.h
@@ -0,0 +1,119 @@
+/**
+ * @file
+ *
+ * AutoIP Automatic LinkLocal IP Configuration
+ */
+
+/*
+ *
+ * Copyright (c) 2007 Dominik Spies <kontakt@dspies.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * Author: Dominik Spies <kontakt@dspies.de>
+ *
+ * This is a AutoIP implementation for the lwIP TCP/IP stack. It aims to conform
+ * with RFC 3927.
+ *
+ *
+ * Please coordinate changes and requests with Dominik Spies
+ * <kontakt@dspies.de>
+ */
+ 
+#ifndef __LWIP_AUTOIP_H__
+#define __LWIP_AUTOIP_H__
+
+#include "lwip/opt.h"
+
+#if LWIP_AUTOIP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/netif.h"
+#include "lwip/udp.h"
+#include "netif/etharp.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* AutoIP Timing */
+#define AUTOIP_TMR_INTERVAL      100
+#define AUTOIP_TICKS_PER_SECOND (1000 / AUTOIP_TMR_INTERVAL)
+
+/* RFC 3927 Constants */
+#define PROBE_WAIT               1   /* second   (initial random delay)                 */
+#define PROBE_MIN                1   /* second   (minimum delay till repeated probe)    */
+#define PROBE_MAX                2   /* seconds  (maximum delay till repeated probe)    */
+#define PROBE_NUM                3   /*          (number of probe packets)              */
+#define ANNOUNCE_NUM             2   /*          (number of announcement packets)       */
+#define ANNOUNCE_INTERVAL        2   /* seconds  (time between announcement packets)    */
+#define ANNOUNCE_WAIT            2   /* seconds  (delay before announcing)              */
+#define MAX_CONFLICTS            10  /*          (max conflicts before rate limiting)   */
+#define RATE_LIMIT_INTERVAL      60  /* seconds  (delay between successive attempts)    */
+#define DEFEND_INTERVAL          10  /* seconds  (min. wait between defensive ARPs)     */
+
+/* AutoIP client states */
+#define AUTOIP_STATE_OFF         0
+#define AUTOIP_STATE_PROBING     1
+#define AUTOIP_STATE_ANNOUNCING  2
+#define AUTOIP_STATE_BOUND       3
+
+struct autoip
+{
+  ip_addr_t llipaddr;       /* the currently selected, probed, announced or used LL IP-Address */
+  u8_t state;               /* current AutoIP state machine state */
+  u8_t sent_num;            /* sent number of probes or announces, dependent on state */
+  u16_t ttw;                /* ticks to wait, tick is AUTOIP_TMR_INTERVAL long */
+  u8_t lastconflict;        /* ticks until a conflict can be solved by defending */
+  u8_t tried_llipaddr;      /* total number of probed/used Link Local IP-Addresses */
+};
+
+
+/** Init srand, has to be called before entering mainloop */
+void autoip_init(void);
+
+/** Set a struct autoip allocated by the application to work with */
+void autoip_set_struct(struct netif *netif, struct autoip *autoip);
+
+/** Start AutoIP client */
+err_t autoip_start(struct netif *netif);
+
+/** Stop AutoIP client */
+err_t autoip_stop(struct netif *netif);
+
+/** Handles every incoming ARP Packet, called by etharp_arp_input */
+void autoip_arp_reply(struct netif *netif, struct etharp_hdr *hdr);
+
+/** Has to be called in loop every AUTOIP_TMR_INTERVAL milliseconds */
+void autoip_tmr(void);
+
+/** Handle a possible change in the network configuration */
+void autoip_network_changed(struct netif *netif);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_AUTOIP */
+
+#endif /* __LWIP_AUTOIP_H__ */
diff --git a/core/lwip/src/include/ipv4/lwip/icmp.h b/core/lwip/src/include/ipv4/lwip/icmp.h
new file mode 100644
index 00000000..d47a7d8a
--- /dev/null
+++ b/core/lwip/src/include/ipv4/lwip/icmp.h
@@ -0,0 +1,111 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_ICMP_H__
+#define __LWIP_ICMP_H__
+
+#include "lwip/opt.h"
+#include "lwip/pbuf.h"
+#include "lwip/ip_addr.h"
+#include "lwip/netif.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define ICMP_ER   0    /* echo reply */
+#define ICMP_DUR  3    /* destination unreachable */
+#define ICMP_SQ   4    /* source quench */
+#define ICMP_RD   5    /* redirect */
+#define ICMP_ECHO 8    /* echo */
+#define ICMP_TE  11    /* time exceeded */
+#define ICMP_PP  12    /* parameter problem */
+#define ICMP_TS  13    /* timestamp */
+#define ICMP_TSR 14    /* timestamp reply */
+#define ICMP_IRQ 15    /* information request */
+#define ICMP_IR  16    /* information reply */
+
+enum icmp_dur_type {
+  ICMP_DUR_NET   = 0,  /* net unreachable */
+  ICMP_DUR_HOST  = 1,  /* host unreachable */
+  ICMP_DUR_PROTO = 2,  /* protocol unreachable */
+  ICMP_DUR_PORT  = 3,  /* port unreachable */
+  ICMP_DUR_FRAG  = 4,  /* fragmentation needed and DF set */
+  ICMP_DUR_SR    = 5   /* source route failed */
+};
+
+enum icmp_te_type {
+  ICMP_TE_TTL  = 0,    /* time to live exceeded in transit */
+  ICMP_TE_FRAG = 1     /* fragment reassembly time exceeded */
+};
+
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+/** This is the standard ICMP header only that the u32_t data
+ *  is splitted to two u16_t like ICMP echo needs it.
+ *  This header is also used for other ICMP types that do not
+ *  use the data part.
+ */
+PACK_STRUCT_BEGIN
+struct icmp_echo_hdr {
+  PACK_STRUCT_FIELD(u8_t type);
+  PACK_STRUCT_FIELD(u8_t code);
+  PACK_STRUCT_FIELD(u16_t chksum);
+  PACK_STRUCT_FIELD(u16_t id);
+  PACK_STRUCT_FIELD(u16_t seqno);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+#define ICMPH_TYPE(hdr) ((hdr)->type)
+#define ICMPH_CODE(hdr) ((hdr)->code)
+
+/** Combines type and code to an u16_t */
+#define ICMPH_TYPE_SET(hdr, t) ((hdr)->type = (t))
+#define ICMPH_CODE_SET(hdr, c) ((hdr)->code = (c))
+
+
+#if LWIP_ICMP /* don't build if not configured for use in lwipopts.h */
+
+void icmp_input(struct pbuf *p, struct netif *inp);
+void icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t);
+void icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t);
+
+#endif /* LWIP_ICMP */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_ICMP_H__ */
diff --git a/core/lwip/src/include/ipv4/lwip/igmp.h b/core/lwip/src/include/ipv4/lwip/igmp.h
new file mode 100644
index 00000000..8aabac24
--- /dev/null
+++ b/core/lwip/src/include/ipv4/lwip/igmp.h
@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2002 CITEL Technologies Ltd.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions 
+ * are met: 
+ * 1. Redistributions of source code must retain the above copyright 
+ *    notice, this list of conditions and the following disclaimer. 
+ * 2. Redistributions in binary form must reproduce the above copyright 
+ *    notice, this list of conditions and the following disclaimer in the 
+ *    documentation and/or other materials provided with the distribution. 
+ * 3. Neither the name of CITEL Technologies Ltd nor the names of its contributors 
+ *    may be used to endorse or promote products derived from this software 
+ *    without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY CITEL TECHNOLOGIES AND CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
+ * ARE DISCLAIMED.  IN NO EVENT SHALL CITEL TECHNOLOGIES OR CONTRIBUTORS BE LIABLE 
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
+ * SUCH DAMAGE. 
+ *
+ * This file is a contribution to the lwIP TCP/IP stack.
+ * The Swedish Institute of Computer Science and Adam Dunkels
+ * are specifically granted permission to redistribute this
+ * source code.
+*/
+
+#ifndef __LWIP_IGMP_H__
+#define __LWIP_IGMP_H__
+
+#include "lwip/opt.h"
+#include "lwip/ip_addr.h"
+#include "lwip/netif.h"
+#include "lwip/pbuf.h"
+
+#if LWIP_IGMP /* don't build if not configured for use in lwipopts.h */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/* IGMP timer */
+#define IGMP_TMR_INTERVAL              100 /* Milliseconds */
+#define IGMP_V1_DELAYING_MEMBER_TMR   (1000/IGMP_TMR_INTERVAL)
+#define IGMP_JOIN_DELAYING_MEMBER_TMR (500 /IGMP_TMR_INTERVAL)
+
+/* MAC Filter Actions, these are passed to a netif's
+ * igmp_mac_filter callback function. */
+#define IGMP_DEL_MAC_FILTER            0
+#define IGMP_ADD_MAC_FILTER            1
+
+
+/**
+ * igmp group structure - there is
+ * a list of groups for each interface
+ * these should really be linked from the interface, but
+ * if we keep them separate we will not affect the lwip original code
+ * too much
+ * 
+ * There will be a group for the all systems group address but this 
+ * will not run the state machine as it is used to kick off reports
+ * from all the other groups
+ */
+struct igmp_group {
+  /** next link */
+  struct igmp_group *next;
+  /** interface on which the group is active */
+  struct netif      *netif;
+  /** multicast address */
+  ip_addr_t          group_address;
+  /** signifies we were the last person to report */
+  u8_t               last_reporter_flag;
+  /** current state of the group */
+  u8_t               group_state;
+  /** timer for reporting, negative is OFF */
+  u16_t              timer;
+  /** counter of simultaneous uses */
+  u8_t               use;
+};
+
+/*  Prototypes */
+void   igmp_init(void);
+err_t  igmp_start(struct netif *netif);
+err_t  igmp_stop(struct netif *netif);
+void   igmp_report_groups(struct netif *netif);
+struct igmp_group *igmp_lookfor_group(struct netif *ifp, ip_addr_t *addr);
+void   igmp_input(struct pbuf *p, struct netif *inp, ip_addr_t *dest);
+err_t  igmp_joingroup(ip_addr_t *ifaddr, ip_addr_t *groupaddr);
+err_t  igmp_leavegroup(ip_addr_t *ifaddr, ip_addr_t *groupaddr);
+void   igmp_tmr(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_IGMP */
+
+#endif /* __LWIP_IGMP_H__ */
diff --git a/core/lwip/src/include/ipv4/lwip/inet.h b/core/lwip/src/include/ipv4/lwip/inet.h
new file mode 100644
index 00000000..0513c740
--- /dev/null
+++ b/core/lwip/src/include/ipv4/lwip/inet.h
@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_INET_H__
+#define __LWIP_INET_H__
+
+#include "lwip/opt.h"
+#include "lwip/def.h"
+#include "lwip/ip_addr.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** For compatibility with BSD code */
+#include <netinet/in.h>
+
+/** 255.255.255.255 */
+#define INADDR_NONE         IPADDR_NONE
+/** 127.0.0.1 */
+#define INADDR_LOOPBACK     IPADDR_LOOPBACK
+/** 0.0.0.0 */
+#define INADDR_ANY          IPADDR_ANY
+/** 255.255.255.255 */
+#define INADDR_BROADCAST    IPADDR_BROADCAST
+
+/* Definitions of the bits in an Internet address integer.
+
+   On subnets, host and network parts are found according to
+   the subnet mask, not these masks.  */
+#define IN_CLASSA(a)        IP_CLASSA(a)
+#define IN_CLASSA_NET       IP_CLASSA_NET
+#define IN_CLASSA_NSHIFT    IP_CLASSA_NSHIFT
+#define IN_CLASSA_HOST      IP_CLASSA_HOST
+#define IN_CLASSA_MAX       IP_CLASSA_MAX
+
+#define IN_CLASSB(b)        IP_CLASSB(b)
+#define IN_CLASSB_NET       IP_CLASSB_NET
+#define IN_CLASSB_NSHIFT    IP_CLASSB_NSHIFT
+#define IN_CLASSB_HOST      IP_CLASSB_HOST
+#define IN_CLASSB_MAX       IP_CLASSB_MAX
+
+#define IN_CLASSC(c)        IP_CLASSC(c)
+#define IN_CLASSC_NET       IP_CLASSC_NET
+#define IN_CLASSC_NSHIFT    IP_CLASSC_NSHIFT
+#define IN_CLASSC_HOST      IP_CLASSC_HOST
+#define IN_CLASSC_MAX       IP_CLASSC_MAX
+
+#define IN_CLASSD(d)        IP_CLASSD(d)
+#define IN_CLASSD_NET       IP_CLASSD_NET     /* These ones aren't really */
+#define IN_CLASSD_NSHIFT    IP_CLASSD_NSHIFT  /*   net and host fields, but */
+#define IN_CLASSD_HOST      IP_CLASSD_HOST    /*   routing needn't know. */
+#define IN_CLASSD_MAX       IP_CLASSD_MAX
+
+#define IN_MULTICAST(a)     IP_MULTICAST(a)
+
+#define IN_EXPERIMENTAL(a)  IP_EXPERIMENTAL(a)
+#define IN_BADCLASS(a)      IP_BADCLASS(a)
+
+#define IN_LOOPBACKNET      IP_LOOPBACKNET
+
+#define inet_addr_from_ipaddr(target_inaddr, source_ipaddr) ((target_inaddr)->s_addr = ip4_addr_get_u32(source_ipaddr))
+#define inet_addr_to_ipaddr(target_ipaddr, source_inaddr)   (ip4_addr_set_u32(target_ipaddr, (source_inaddr)->s_addr))
+/* ATTENTION: the next define only works because both s_addr and ip_addr_t are an u32_t effectively! */
+#define inet_addr_to_ipaddr_p(target_ipaddr_p, source_inaddr)   ((target_ipaddr_p) = (ip_addr_t*)&((source_inaddr)->s_addr))
+
+/* directly map this to the lwip internal functions */
+#define inet_addr(cp)         ipaddr_addr(cp)
+#define inet_aton(cp, addr)   ipaddr_aton(cp, (ip_addr_t*)addr)
+#define inet_ntoa(addr)       ipaddr_ntoa((ip_addr_t*)&(addr))
+#define inet_ntoa_r(addr, buf, buflen) ipaddr_ntoa_r((ip_addr_t*)&(addr), buf, buflen)
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_INET_H__ */
diff --git a/core/lwip/src/include/ipv4/lwip/inet_chksum.h b/core/lwip/src/include/ipv4/lwip/inet_chksum.h
new file mode 100644
index 00000000..79a2d90f
--- /dev/null
+++ b/core/lwip/src/include/ipv4/lwip/inet_chksum.h
@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_INET_CHKSUM_H__
+#define __LWIP_INET_CHKSUM_H__
+
+#include "lwip/opt.h"
+
+#include "lwip/pbuf.h"
+#include "lwip/ip_addr.h"
+
+/** Swap the bytes in an u16_t: much like htons() for little-endian */
+#ifndef SWAP_BYTES_IN_WORD
+#if LWIP_PLATFORM_BYTESWAP && (BYTE_ORDER == LITTLE_ENDIAN)
+/* little endian and PLATFORM_BYTESWAP defined */
+#define SWAP_BYTES_IN_WORD(w) LWIP_PLATFORM_HTONS(w)
+#else /* LWIP_PLATFORM_BYTESWAP && (BYTE_ORDER == LITTLE_ENDIAN) */
+/* can't use htons on big endian (or PLATFORM_BYTESWAP not defined)... */
+#define SWAP_BYTES_IN_WORD(w) (((w) & 0xff) << 8) | (((w) & 0xff00) >> 8)
+#endif /* LWIP_PLATFORM_BYTESWAP && (BYTE_ORDER == LITTLE_ENDIAN)*/
+#endif /* SWAP_BYTES_IN_WORD */
+
+/** Split an u32_t in two u16_ts and add them up */
+#ifndef FOLD_U32T
+#define FOLD_U32T(u)          (((u) >> 16) + ((u) & 0x0000ffffUL))
+#endif
+
+#if LWIP_CHECKSUM_ON_COPY
+/** Function-like macro: same as MEMCPY but returns the checksum of copied data
+    as u16_t */
+#ifndef LWIP_CHKSUM_COPY
+#define LWIP_CHKSUM_COPY(dst, src, len) lwip_chksum_copy(dst, src, len)
+#ifndef LWIP_CHKSUM_COPY_ALGORITHM
+#define LWIP_CHKSUM_COPY_ALGORITHM 1
+#endif /* LWIP_CHKSUM_COPY_ALGORITHM */
+#endif /* LWIP_CHKSUM_COPY */
+#else /* LWIP_CHECKSUM_ON_COPY */
+#define LWIP_CHKSUM_COPY_ALGORITHM 0
+#endif /* LWIP_CHECKSUM_ON_COPY */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+u16_t inet_chksum(void *dataptr, u16_t len);
+u16_t inet_chksum_pbuf(struct pbuf *p);
+u16_t inet_chksum_pseudo(struct pbuf *p,
+       ip_addr_t *src, ip_addr_t *dest,
+       u8_t proto, u16_t proto_len);
+u16_t inet_chksum_pseudo_partial(struct pbuf *p,
+       ip_addr_t *src, ip_addr_t *dest,
+       u8_t proto, u16_t proto_len, u16_t chksum_len);
+#if LWIP_CHKSUM_COPY_ALGORITHM
+u16_t lwip_chksum_copy(void *dst, const void *src, u16_t len);
+#endif /* LWIP_CHKSUM_COPY_ALGORITHM */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_INET_H__ */
+
diff --git a/core/lwip/src/include/ipv4/lwip/ip.h b/core/lwip/src/include/ipv4/lwip/ip.h
new file mode 100644
index 00000000..74f501d1
--- /dev/null
+++ b/core/lwip/src/include/ipv4/lwip/ip.h
@@ -0,0 +1,213 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_IP_H__
+#define __LWIP_IP_H__
+
+#include "lwip/opt.h"
+
+#include "lwip/def.h"
+#include "lwip/pbuf.h"
+#include "lwip/ip_addr.h"
+#include "lwip/err.h"
+#include "lwip/netif.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** Currently, the function ip_output_if_opt() is only used with IGMP */
+#define IP_OPTIONS_SEND   LWIP_IGMP
+
+#define IP_HLEN 20
+
+#define IP_PROTO_ICMP    1
+#define IP_PROTO_IGMP    2
+#define IP_PROTO_UDP     17
+#define IP_PROTO_UDPLITE 136
+#define IP_PROTO_TCP     6
+
+/* This is passed as the destination address to ip_output_if (not
+   to ip_output), meaning that an IP header already is constructed
+   in the pbuf. This is used when TCP retransmits. */
+#ifdef IP_HDRINCL
+#undef IP_HDRINCL
+#endif /* IP_HDRINCL */
+#define IP_HDRINCL  NULL
+
+#if LWIP_NETIF_HWADDRHINT
+#define IP_PCB_ADDRHINT ;u8_t addr_hint
+#else
+#define IP_PCB_ADDRHINT
+#endif /* LWIP_NETIF_HWADDRHINT */
+
+/* This is the common part of all PCB types. It needs to be at the
+   beginning of a PCB type definition. It is located here so that
+   changes to this common part are made in one location instead of
+   having to change all PCB structs. */
+#define IP_PCB \
+  /* ip addresses in network byte order */ \
+  ip_addr_t local_ip; \
+  ip_addr_t remote_ip; \
+   /* Socket options */  \
+  u8_t so_options;      \
+   /* Type Of Service */ \
+  u8_t tos;              \
+  /* Time To Live */     \
+  u8_t ttl               \
+  /* link layer address resolution hint */ \
+  IP_PCB_ADDRHINT
+
+struct ip_pcb {
+/* Common members of all PCB types */
+  IP_PCB;
+};
+
+/*
+ * Option flags per-socket. These are the same like SO_XXX.
+ */
+/*#define SOF_DEBUG       (u8_t)0x01U     Unimplemented: turn on debugging info recording */
+#define SOF_ACCEPTCONN    (u8_t)0x02U  /* socket has had listen() */
+#define SOF_REUSEADDR     (u8_t)0x04U  /* allow local address reuse */
+#define SOF_KEEPALIVE     (u8_t)0x08U  /* keep connections alive */
+/*#define SOF_DONTROUTE   (u8_t)0x10U     Unimplemented: just use interface addresses */
+#define SOF_BROADCAST     (u8_t)0x20U  /* permit to send and to receive broadcast messages (see IP_SOF_BROADCAST option) */
+/*#define SOF_USELOOPBACK (u8_t)0x40U     Unimplemented: bypass hardware when possible */
+#define SOF_LINGER        (u8_t)0x80U  /* linger on close if data present */
+/*#define SOF_OOBINLINE   (u16_t)0x0100U     Unimplemented: leave received OOB data in line */
+/*#define SOF_REUSEPORT   (u16_t)0x0200U     Unimplemented: allow local address & port reuse */
+
+/* These flags are inherited (e.g. from a listen-pcb to a connection-pcb): */
+#define SOF_INHERITED   (SOF_REUSEADDR|SOF_KEEPALIVE|SOF_LINGER/*|SOF_DEBUG|SOF_DONTROUTE|SOF_OOBINLINE*/)
+
+
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct ip_hdr {
+  /* version / header length / type of service */
+  PACK_STRUCT_FIELD(u16_t _v_hl_tos);
+  /* total length */
+  PACK_STRUCT_FIELD(u16_t _len);
+  /* identification */
+  PACK_STRUCT_FIELD(u16_t _id);
+  /* fragment offset field */
+  PACK_STRUCT_FIELD(u16_t _offset);
+#define IP_RF 0x8000U        /* reserved fragment flag */
+#define IP_DF 0x4000U        /* dont fragment flag */
+#define IP_MF 0x2000U        /* more fragments flag */
+#define IP_OFFMASK 0x1fffU   /* mask for fragmenting bits */
+  /* time to live */
+  PACK_STRUCT_FIELD(u8_t _ttl);
+  /* protocol*/
+  PACK_STRUCT_FIELD(u8_t _proto);
+  /* checksum */
+  PACK_STRUCT_FIELD(u16_t _chksum);
+  /* source and destination IP addresses */
+  PACK_STRUCT_FIELD(ip_addr_p_t src);
+  PACK_STRUCT_FIELD(ip_addr_p_t dest); 
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+#define IPH_V(hdr)  (ntohs((hdr)->_v_hl_tos) >> 12)
+#define IPH_HL(hdr) ((ntohs((hdr)->_v_hl_tos) >> 8) & 0x0f)
+#define IPH_TOS(hdr) (ntohs((hdr)->_v_hl_tos) & 0xff)
+#define IPH_LEN(hdr) ((hdr)->_len)
+#define IPH_ID(hdr) ((hdr)->_id)
+#define IPH_OFFSET(hdr) ((hdr)->_offset)
+#define IPH_TTL(hdr) ((hdr)->_ttl)
+#define IPH_PROTO(hdr) ((hdr)->_proto)
+#define IPH_CHKSUM(hdr) ((hdr)->_chksum)
+
+#define IPH_VHLTOS_SET(hdr, v, hl, tos) (hdr)->_v_hl_tos = (htons(((v) << 12) | ((hl) << 8) | (tos)))
+#define IPH_LEN_SET(hdr, len) (hdr)->_len = (len)
+#define IPH_ID_SET(hdr, id) (hdr)->_id = (id)
+#define IPH_OFFSET_SET(hdr, off) (hdr)->_offset = (off)
+#define IPH_TTL_SET(hdr, ttl) (hdr)->_ttl = (u8_t)(ttl)
+#define IPH_PROTO_SET(hdr, proto) (hdr)->_proto = (u8_t)(proto)
+#define IPH_CHKSUM_SET(hdr, chksum) (hdr)->_chksum = (chksum)
+
+/** The interface that provided the packet for the current callback invocation. */
+extern struct netif *current_netif;
+/** Header of the input packet currently being processed. */
+extern const struct ip_hdr *current_header;
+/** Source IP address of current_header */
+extern ip_addr_t current_iphdr_src;
+/** Destination IP address of current_header */
+extern ip_addr_t current_iphdr_dest;
+
+#define ip_init() /* Compatibility define, not init needed. */
+struct netif *ip_route(ip_addr_t *dest);
+err_t ip_input(struct pbuf *p, struct netif *inp);
+err_t ip_output(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest,
+       u8_t ttl, u8_t tos, u8_t proto);
+err_t ip_output_if(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest,
+       u8_t ttl, u8_t tos, u8_t proto,
+       struct netif *netif);
+#if LWIP_NETIF_HWADDRHINT
+err_t ip_output_hinted(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest,
+       u8_t ttl, u8_t tos, u8_t proto, u8_t *addr_hint);
+#endif /* LWIP_NETIF_HWADDRHINT */
+#if IP_OPTIONS_SEND
+err_t ip_output_if_opt(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest,
+       u8_t ttl, u8_t tos, u8_t proto, struct netif *netif, void *ip_options,
+       u16_t optlen);
+#endif /* IP_OPTIONS_SEND */
+/** Get the interface that received the current packet.
+ * This function must only be called from a receive callback (udp_recv,
+ * raw_recv, tcp_accept). It will return NULL otherwise. */
+#define ip_current_netif()  (current_netif)
+/** Get the IP header of the current packet.
+ * This function must only be called from a receive callback (udp_recv,
+ * raw_recv, tcp_accept). It will return NULL otherwise. */
+#define ip_current_header() (current_header)
+/** Source IP address of current_header */
+#define ip_current_src_addr()  (&current_iphdr_src)
+/** Destination IP address of current_header */
+#define ip_current_dest_addr() (&current_iphdr_dest)
+
+#if IP_DEBUG
+void ip_debug_print(struct pbuf *p);
+#else
+#define ip_debug_print(p)
+#endif /* IP_DEBUG */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_IP_H__ */
+
+
diff --git a/core/lwip/src/include/ipv4/lwip/ip_addr.h b/core/lwip/src/include/ipv4/lwip/ip_addr.h
new file mode 100644
index 00000000..77f84e02
--- /dev/null
+++ b/core/lwip/src/include/ipv4/lwip/ip_addr.h
@@ -0,0 +1,244 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_IP_ADDR_H__
+#define __LWIP_IP_ADDR_H__
+
+#include "lwip/opt.h"
+#include "lwip/def.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* This is the aligned version of ip_addr_t,
+   used as local variable, on the stack, etc. */
+struct ip_addr {
+  u32_t addr;
+};
+
+/* This is the packed version of ip_addr_t,
+   used in network headers that are itself packed */
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct ip_addr_packed {
+  PACK_STRUCT_FIELD(u32_t addr);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+/** ip_addr_t uses a struct for convenience only, so that the same defines can
+ * operate both on ip_addr_t as well as on ip_addr_p_t. */
+typedef struct ip_addr ip_addr_t;
+typedef struct ip_addr_packed ip_addr_p_t;
+
+/*
+ * struct ipaddr2 is used in the definition of the ARP packet format in
+ * order to support compilers that don't have structure packing.
+ */
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct ip_addr2 {
+  PACK_STRUCT_FIELD(u16_t addrw[2]);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+/* Forward declaration to not include netif.h */
+struct netif;
+
+extern const ip_addr_t ip_addr_any;
+extern const ip_addr_t ip_addr_broadcast;
+
+/** IP_ADDR_ can be used as a fixed IP address
+ *  for the wildcard and the broadcast address
+ */
+#define IP_ADDR_ANY         ((ip_addr_t *)&ip_addr_any)
+#define IP_ADDR_BROADCAST   ((ip_addr_t *)&ip_addr_broadcast)
+
+/** 255.255.255.255 */
+#define IPADDR_NONE         ((u32_t)0xffffffffUL)
+/** 127.0.0.1 */
+#define IPADDR_LOOPBACK     ((u32_t)0x7f000001UL)
+/** 0.0.0.0 */
+#define IPADDR_ANY          ((u32_t)0x00000000UL)
+/** 255.255.255.255 */
+#define IPADDR_BROADCAST    ((u32_t)0xffffffffUL)
+
+/* Definitions of the bits in an Internet address integer.
+
+   On subnets, host and network parts are found according to
+   the subnet mask, not these masks.  */
+#define IP_CLASSA(a)        ((((u32_t)(a)) & 0x80000000UL) == 0)
+#define IP_CLASSA_NET       0xff000000
+#define IP_CLASSA_NSHIFT    24
+#define IP_CLASSA_HOST      (0xffffffff & ~IP_CLASSA_NET)
+#define IP_CLASSA_MAX       128
+
+#define IP_CLASSB(a)        ((((u32_t)(a)) & 0xc0000000UL) == 0x80000000UL)
+#define IP_CLASSB_NET       0xffff0000
+#define IP_CLASSB_NSHIFT    16
+#define IP_CLASSB_HOST      (0xffffffff & ~IP_CLASSB_NET)
+#define IP_CLASSB_MAX       65536
+
+#define IP_CLASSC(a)        ((((u32_t)(a)) & 0xe0000000UL) == 0xc0000000UL)
+#define IP_CLASSC_NET       0xffffff00
+#define IP_CLASSC_NSHIFT    8
+#define IP_CLASSC_HOST      (0xffffffff & ~IP_CLASSC_NET)
+
+#define IP_CLASSD(a)        (((u32_t)(a) & 0xf0000000UL) == 0xe0000000UL)
+#define IP_CLASSD_NET       0xf0000000          /* These ones aren't really */
+#define IP_CLASSD_NSHIFT    28                  /*   net and host fields, but */
+#define IP_CLASSD_HOST      0x0fffffff          /*   routing needn't know. */
+#define IP_MULTICAST(a)     IP_CLASSD(a)
+
+#define IP_EXPERIMENTAL(a)  (((u32_t)(a) & 0xf0000000UL) == 0xf0000000UL)
+#define IP_BADCLASS(a)      (((u32_t)(a) & 0xf0000000UL) == 0xf0000000UL)
+
+#define IP_LOOPBACKNET      127                 /* official! */
+
+
+#if BYTE_ORDER == BIG_ENDIAN
+/** Set an IP address given by the four byte-parts */
+#define IP4_ADDR(ipaddr, a,b,c,d) \
+        (ipaddr)->addr = ((u32_t)((a) & 0xff) << 24) | \
+                         ((u32_t)((b) & 0xff) << 16) | \
+                         ((u32_t)((c) & 0xff) << 8)  | \
+                          (u32_t)((d) & 0xff)
+#else
+/** Set an IP address given by the four byte-parts.
+    Little-endian version that prevents the use of htonl. */
+#define IP4_ADDR(ipaddr, a,b,c,d) \
+        (ipaddr)->addr = ((u32_t)((d) & 0xff) << 24) | \
+                         ((u32_t)((c) & 0xff) << 16) | \
+                         ((u32_t)((b) & 0xff) << 8)  | \
+                          (u32_t)((a) & 0xff)
+#endif
+
+/** MEMCPY-like copying of IP addresses where addresses are known to be
+ * 16-bit-aligned if the port is correctly configured (so a port could define
+ * this to copying 2 u16_t's) - no NULL-pointer-checking needed. */
+#ifndef IPADDR2_COPY
+#define IPADDR2_COPY(dest, src) SMEMCPY(dest, src, sizeof(ip_addr_t))
+#endif
+
+/** Copy IP address - faster than ip_addr_set: no NULL check */
+#define ip_addr_copy(dest, src) ((dest).addr = (src).addr)
+/** Safely copy one IP address to another (src may be NULL) */
+#define ip_addr_set(dest, src) ((dest)->addr = \
+                                    ((src) == NULL ? 0 : \
+                                    (src)->addr))
+/** Set complete address to zero */
+#define ip_addr_set_zero(ipaddr)      ((ipaddr)->addr = 0)
+/** Set address to IPADDR_ANY (no need for htonl()) */
+#define ip_addr_set_any(ipaddr)       ((ipaddr)->addr = IPADDR_ANY)
+/** Set address to loopback address */
+#define ip_addr_set_loopback(ipaddr)  ((ipaddr)->addr = PP_HTONL(IPADDR_LOOPBACK))
+/** Safely copy one IP address to another and change byte order
+ * from host- to network-order. */
+#define ip_addr_set_hton(dest, src) ((dest)->addr = \
+                               ((src) == NULL ? 0:\
+                               htonl((src)->addr)))
+/** IPv4 only: set the IP address given as an u32_t */
+#define ip4_addr_set_u32(dest_ipaddr, src_u32) ((dest_ipaddr)->addr = (src_u32))
+/** IPv4 only: get the IP address as an u32_t */
+#define ip4_addr_get_u32(src_ipaddr) ((src_ipaddr)->addr)
+
+/** Get the network address by combining host address with netmask */
+#define ip_addr_get_network(target, host, netmask) ((target)->addr = ((host)->addr) & ((netmask)->addr))
+
+/**
+ * Determine if two address are on the same network.
+ *
+ * @arg addr1 IP address 1
+ * @arg addr2 IP address 2
+ * @arg mask network identifier mask
+ * @return !0 if the network identifiers of both address match
+ */
+#define ip_addr_netcmp(addr1, addr2, mask) (((addr1)->addr & \
+                                              (mask)->addr) == \
+                                             ((addr2)->addr & \
+                                              (mask)->addr))
+#define ip_addr_cmp(addr1, addr2) ((addr1)->addr == (addr2)->addr)
+
+#define ip_addr_isany(addr1) ((addr1) == NULL || (addr1)->addr == IPADDR_ANY)
+
+#define ip_addr_isbroadcast(ipaddr, netif) ip4_addr_isbroadcast((ipaddr)->addr, (netif))
+u8_t ip4_addr_isbroadcast(u32_t addr, const struct netif *netif);
+
+#define ip_addr_netmask_valid(netmask) ip4_addr_netmask_valid((netmask)->addr)
+u8_t ip4_addr_netmask_valid(u32_t netmask);
+
+#define ip_addr_ismulticast(addr1) (((addr1)->addr & PP_HTONL(0xf0000000UL)) == PP_HTONL(0xe0000000UL))
+
+#define ip_addr_islinklocal(addr1) (((addr1)->addr & PP_HTONL(0xffff0000UL)) == PP_HTONL(0xa9fe0000UL))
+
+#define ip_addr_debug_print(debug, ipaddr) \
+  LWIP_DEBUGF(debug, ("%"U16_F".%"U16_F".%"U16_F".%"U16_F,             \
+                      ipaddr != NULL ? ip4_addr1_16(ipaddr) : 0,       \
+                      ipaddr != NULL ? ip4_addr2_16(ipaddr) : 0,       \
+                      ipaddr != NULL ? ip4_addr3_16(ipaddr) : 0,       \
+                      ipaddr != NULL ? ip4_addr4_16(ipaddr) : 0))
+
+/* Get one byte from the 4-byte address */
+#define ip4_addr1(ipaddr) (((u8_t*)(ipaddr))[0])
+#define ip4_addr2(ipaddr) (((u8_t*)(ipaddr))[1])
+#define ip4_addr3(ipaddr) (((u8_t*)(ipaddr))[2])
+#define ip4_addr4(ipaddr) (((u8_t*)(ipaddr))[3])
+/* These are cast to u16_t, with the intent that they are often arguments
+ * to printf using the U16_F format from cc.h. */
+#define ip4_addr1_16(ipaddr) ((u16_t)ip4_addr1(ipaddr))
+#define ip4_addr2_16(ipaddr) ((u16_t)ip4_addr2(ipaddr))
+#define ip4_addr3_16(ipaddr) ((u16_t)ip4_addr3(ipaddr))
+#define ip4_addr4_16(ipaddr) ((u16_t)ip4_addr4(ipaddr))
+
+/** For backwards compatibility */
+#define ip_ntoa(ipaddr)  ipaddr_ntoa(ipaddr)
+
+u32_t ipaddr_addr(const char *cp);
+int ipaddr_aton(const char *cp, ip_addr_t *addr);
+/** returns ptr to static buffer; not reentrant! */
+char *ipaddr_ntoa(const ip_addr_t *addr);
+char *ipaddr_ntoa_r(const ip_addr_t *addr, char *buf, int buflen);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_IP_ADDR_H__ */
diff --git a/core/lwip/src/include/ipv4/lwip/ip_frag.h b/core/lwip/src/include/ipv4/lwip/ip_frag.h
new file mode 100644
index 00000000..77b5eb1e
--- /dev/null
+++ b/core/lwip/src/include/ipv4/lwip/ip_frag.h
@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Jani Monoses <jani@iv.ro>
+ *
+ */
+
+#ifndef __LWIP_IP_FRAG_H__
+#define __LWIP_IP_FRAG_H__
+
+#include "lwip/opt.h"
+#include "lwip/err.h"
+#include "lwip/pbuf.h"
+#include "lwip/netif.h"
+#include "lwip/ip_addr.h"
+#include "lwip/ip.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if IP_REASSEMBLY
+/* The IP reassembly timer interval in milliseconds. */
+#define IP_TMR_INTERVAL 1000
+
+/* IP reassembly helper struct.
+ * This is exported because memp needs to know the size.
+ */
+struct ip_reassdata {
+  struct ip_reassdata *next;
+  struct pbuf *p;
+  struct ip_hdr iphdr;
+  u16_t datagram_len;
+  u8_t flags;
+  u8_t timer;
+};
+
+void ip_reass_init(void);
+void ip_reass_tmr(void);
+struct pbuf * ip_reass(struct pbuf *p);
+#endif /* IP_REASSEMBLY */
+
+#if IP_FRAG
+#if !IP_FRAG_USES_STATIC_BUF && !LWIP_NETIF_TX_SINGLE_PBUF
+/** A custom pbuf that holds a reference to another pbuf, which is freed
+ * when this custom pbuf is freed. This is used to create a custom PBUF_REF
+ * that points into the original pbuf. */
+struct pbuf_custom_ref {
+  /** 'base class' */
+  struct pbuf_custom pc;
+  /** pointer to the original pbuf that is referenced */
+  struct pbuf *original;
+};
+#endif /* !IP_FRAG_USES_STATIC_BUF && !LWIP_NETIF_TX_SINGLE_PBUF */
+
+err_t ip_frag(struct pbuf *p, struct netif *netif, ip_addr_t *dest);
+#endif /* IP_FRAG */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_IP_FRAG_H__ */
diff --git a/core/lwip/src/include/lwip/api.h b/core/lwip/src/include/lwip/api.h
new file mode 100644
index 00000000..91b9e5d2
--- /dev/null
+++ b/core/lwip/src/include/lwip/api.h
@@ -0,0 +1,284 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_API_H__
+#define __LWIP_API_H__
+
+#include "lwip/opt.h"
+
+#if LWIP_NETCONN /* don't build if not configured for use in lwipopts.h */
+
+#include <stddef.h> /* for size_t */
+
+#include "lwip/netbuf.h"
+#include "lwip/sys.h"
+#include "lwip/ip_addr.h"
+#include "lwip/err.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Throughout this file, IP addresses and port numbers are expected to be in
+ * the same byte order as in the corresponding pcb.
+ */
+
+/* Flags for netconn_write (u8_t) */
+#define NETCONN_NOFLAG    0x00
+#define NETCONN_NOCOPY    0x00 /* Only for source code compatibility */
+#define NETCONN_COPY      0x01
+#define NETCONN_MORE      0x02
+#define NETCONN_DONTBLOCK 0x04
+
+/* Flags for struct netconn.flags (u8_t) */
+/** TCP: when data passed to netconn_write doesn't fit into the send buffer,
+    this temporarily stores whether to wake up the original application task
+    if data couldn't be sent in the first try. */
+#define NETCONN_FLAG_WRITE_DELAYED            0x01
+/** Should this netconn avoid blocking? */
+#define NETCONN_FLAG_NON_BLOCKING             0x02
+/** Was the last connect action a non-blocking one? */
+#define NETCONN_FLAG_IN_NONBLOCKING_CONNECT   0x04
+/** If this is set, a TCP netconn must call netconn_recved() to update
+    the TCP receive window (done automatically if not set). */
+#define NETCONN_FLAG_NO_AUTO_RECVED           0x08
+/** If a nonblocking write has been rejected before, poll_tcp needs to
+    check if the netconn is writable again */
+#define NETCONN_FLAG_CHECK_WRITESPACE         0x10
+
+
+/* Helpers to process several netconn_types by the same code */
+#define NETCONNTYPE_GROUP(t)    (t&0xF0)
+#define NETCONNTYPE_DATAGRAM(t) (t&0xE0)
+
+/** Protocol family and type of the netconn */
+enum netconn_type {
+  NETCONN_INVALID    = 0,
+  /* NETCONN_TCP Group */
+  NETCONN_TCP        = 0x10,
+  /* NETCONN_UDP Group */
+  NETCONN_UDP        = 0x20,
+  NETCONN_UDPLITE    = 0x21,
+  NETCONN_UDPNOCHKSUM= 0x22,
+  /* NETCONN_RAW Group */
+  NETCONN_RAW        = 0x40
+};
+
+/** Current state of the netconn. Non-TCP netconns are always
+ * in state NETCONN_NONE! */
+enum netconn_state {
+  NETCONN_NONE,
+  NETCONN_WRITE,
+  NETCONN_LISTEN,
+  NETCONN_CONNECT,
+  NETCONN_CLOSE
+};
+
+/** Use to inform the callback function about changes */
+enum netconn_evt {
+  NETCONN_EVT_RCVPLUS,
+  NETCONN_EVT_RCVMINUS,
+  NETCONN_EVT_SENDPLUS,
+  NETCONN_EVT_SENDMINUS,
+  NETCONN_EVT_ERROR
+};
+
+#if LWIP_IGMP
+/** Used for netconn_join_leave_group() */
+enum netconn_igmp {
+  NETCONN_JOIN,
+  NETCONN_LEAVE
+};
+#endif /* LWIP_IGMP */
+
+/* forward-declare some structs to avoid to include their headers */
+struct ip_pcb;
+struct tcp_pcb;
+struct udp_pcb;
+struct raw_pcb;
+struct netconn;
+struct api_msg_msg;
+
+/** A callback prototype to inform about events for a netconn */
+typedef void (* netconn_callback)(struct netconn *, enum netconn_evt, u16_t len);
+
+/** A netconn descriptor */
+struct netconn {
+  /** type of the netconn (TCP, UDP or RAW) */
+  enum netconn_type type;
+  /** current state of the netconn */
+  enum netconn_state state;
+  /** the lwIP internal protocol control block */
+  union {
+    struct ip_pcb  *ip;
+    struct tcp_pcb *tcp;
+    struct udp_pcb *udp;
+    struct raw_pcb *raw;
+  } pcb;
+  /** the last error this netconn had */
+  err_t last_err;
+  /** sem that is used to synchroneously execute functions in the core context */
+  sys_sem_t op_completed;
+  /** mbox where received packets are stored until they are fetched
+      by the netconn application thread (can grow quite big) */
+  sys_mbox_t recvmbox;
+#if LWIP_TCP
+  /** mbox where new connections are stored until processed
+      by the application thread */
+  sys_mbox_t acceptmbox;
+#endif /* LWIP_TCP */
+  /** only used for socket layer */
+#if LWIP_SOCKET
+  int socket;
+#endif /* LWIP_SOCKET */
+#if LWIP_SO_RCVTIMEO
+  /** timeout to wait for new data to be received
+      (or connections to arrive for listening netconns) */
+  int recv_timeout;
+#endif /* LWIP_SO_RCVTIMEO */
+#if LWIP_SO_RCVBUF
+  /** maximum amount of bytes queued in recvmbox
+      not used for TCP: adjust TCP_WND instead! */
+  int recv_bufsize;
+  /** number of bytes currently in recvmbox to be received,
+      tested against recv_bufsize to limit bytes on recvmbox
+      for UDP and RAW, used for FIONREAD */
+  s16_t recv_avail;
+#endif /* LWIP_SO_RCVBUF */
+  /** flags holding more netconn-internal state, see NETCONN_FLAG_* defines */
+  u8_t flags;
+#if LWIP_TCP
+  /** TCP: when data passed to netconn_write doesn't fit into the send buffer,
+      this temporarily stores how much is already sent. */
+  size_t write_offset;
+  /** TCP: when data passed to netconn_write doesn't fit into the send buffer,
+      this temporarily stores the message.
+      Also used during connect and close. */
+  struct api_msg_msg *current_msg;
+#endif /* LWIP_TCP */
+  /** A callback function that is informed about events for this netconn */
+  netconn_callback callback;
+};
+
+/** Register an Network connection event */
+#define API_EVENT(c,e,l) if (c->callback) {         \
+                           (*c->callback)(c, e, l); \
+                         }
+
+/** Set conn->last_err to err but don't overwrite fatal errors */
+#define NETCONN_SET_SAFE_ERR(conn, err) do { \
+  SYS_ARCH_DECL_PROTECT(lev); \
+  SYS_ARCH_PROTECT(lev); \
+  if (!ERR_IS_FATAL((conn)->last_err)) { \
+    (conn)->last_err = err; \
+  } \
+  SYS_ARCH_UNPROTECT(lev); \
+} while(0);
+
+/* Network connection functions: */
+#define netconn_new(t)                  netconn_new_with_proto_and_callback(t, 0, NULL)
+#define netconn_new_with_callback(t, c) netconn_new_with_proto_and_callback(t, 0, c)
+struct
+netconn *netconn_new_with_proto_and_callback(enum netconn_type t, u8_t proto,
+                                             netconn_callback callback);
+err_t   netconn_delete(struct netconn *conn);
+/** Get the type of a netconn (as enum netconn_type). */
+#define netconn_type(conn) (conn->type)
+
+err_t   netconn_getaddr(struct netconn *conn, ip_addr_t *addr,
+                        u16_t *port, u8_t local);
+#define netconn_peer(c,i,p) netconn_getaddr(c,i,p,0)
+#define netconn_addr(c,i,p) netconn_getaddr(c,i,p,1)
+
+err_t   netconn_bind(struct netconn *conn, ip_addr_t *addr, u16_t port);
+err_t   netconn_connect(struct netconn *conn, ip_addr_t *addr, u16_t port);
+err_t   netconn_disconnect (struct netconn *conn);
+err_t   netconn_listen_with_backlog(struct netconn *conn, u8_t backlog);
+#define netconn_listen(conn) netconn_listen_with_backlog(conn, TCP_DEFAULT_LISTEN_BACKLOG)
+err_t   netconn_accept(struct netconn *conn, struct netconn **new_conn);
+err_t   netconn_recv(struct netconn *conn, struct netbuf **new_buf);
+err_t   netconn_recv_tcp_pbuf(struct netconn *conn, struct pbuf **new_buf);
+void    netconn_recved(struct netconn *conn, u32_t length);
+err_t   netconn_sendto(struct netconn *conn, struct netbuf *buf,
+                       ip_addr_t *addr, u16_t port);
+err_t   netconn_send(struct netconn *conn, struct netbuf *buf);
+err_t   netconn_write(struct netconn *conn, const void *dataptr, size_t size,
+                      u8_t apiflags);
+err_t   netconn_close(struct netconn *conn);
+err_t   netconn_shutdown(struct netconn *conn, u8_t shut_rx, u8_t shut_tx);
+
+#if LWIP_IGMP
+err_t   netconn_join_leave_group(struct netconn *conn, ip_addr_t *multiaddr,
+                                 ip_addr_t *netif_addr, enum netconn_igmp join_or_leave);
+#endif /* LWIP_IGMP */
+#if LWIP_DNS
+err_t   netconn_gethostbyname(const char *name, ip_addr_t *addr);
+#endif /* LWIP_DNS */
+
+#define netconn_err(conn)               ((conn)->last_err)
+#define netconn_recv_bufsize(conn)      ((conn)->recv_bufsize)
+
+/** Set the blocking status of netconn calls (@todo: write/send is missing) */
+#define netconn_set_nonblocking(conn, val)  do { if(val) { \
+  (conn)->flags |= NETCONN_FLAG_NON_BLOCKING; \
+} else { \
+  (conn)->flags &= ~ NETCONN_FLAG_NON_BLOCKING; }} while(0)
+/** Get the blocking status of netconn calls (@todo: write/send is missing) */
+#define netconn_is_nonblocking(conn)        (((conn)->flags & NETCONN_FLAG_NON_BLOCKING) != 0)
+
+/** TCP: Set the no-auto-recved status of netconn calls (see NETCONN_FLAG_NO_AUTO_RECVED) */
+#define netconn_set_noautorecved(conn, val)  do { if(val) { \
+  (conn)->flags |= NETCONN_FLAG_NO_AUTO_RECVED; \
+} else { \
+  (conn)->flags &= ~ NETCONN_FLAG_NO_AUTO_RECVED; }} while(0)
+/** TCP: Get the no-auto-recved status of netconn calls (see NETCONN_FLAG_NO_AUTO_RECVED) */
+#define netconn_get_noautorecved(conn)        (((conn)->flags & NETCONN_FLAG_NO_AUTO_RECVED) != 0)
+
+#if LWIP_SO_RCVTIMEO
+/** Set the receive timeout in milliseconds */
+#define netconn_set_recvtimeout(conn, timeout)      ((conn)->recv_timeout = (timeout))
+/** Get the receive timeout in milliseconds */
+#define netconn_get_recvtimeout(conn)               ((conn)->recv_timeout)
+#endif /* LWIP_SO_RCVTIMEO */
+#if LWIP_SO_RCVBUF
+/** Set the receive buffer in bytes */
+#define netconn_set_recvbufsize(conn, recvbufsize)  ((conn)->recv_bufsize = (recvbufsize))
+/** Get the receive buffer in bytes */
+#define netconn_get_recvbufsize(conn)               ((conn)->recv_bufsize)
+#endif /* LWIP_SO_RCVBUF*/
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_NETCONN */
+
+#endif /* __LWIP_API_H__ */
diff --git a/core/lwip/src/include/lwip/api_msg.h b/core/lwip/src/include/lwip/api_msg.h
new file mode 100644
index 00000000..f99d8c3b
--- /dev/null
+++ b/core/lwip/src/include/lwip/api_msg.h
@@ -0,0 +1,174 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_API_MSG_H__
+#define __LWIP_API_MSG_H__
+
+#include "lwip/opt.h"
+
+#if LWIP_NETCONN /* don't build if not configured for use in lwipopts.h */
+
+#include <stddef.h> /* for size_t */
+
+#include "lwip/ip_addr.h"
+#include "lwip/err.h"
+#include "lwip/sys.h"
+#include "lwip/igmp.h"
+#include "lwip/api.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* For the netconn API, these values are use as a bitmask! */
+#define NETCONN_SHUT_RD   1
+#define NETCONN_SHUT_WR   2
+#define NETCONN_SHUT_RDWR (NETCONN_SHUT_RD | NETCONN_SHUT_WR)
+
+/* IP addresses and port numbers are expected to be in
+ * the same byte order as in the corresponding pcb.
+ */
+/** This struct includes everything that is necessary to execute a function
+    for a netconn in another thread context (mainly used to process netconns
+    in the tcpip_thread context to be thread safe). */
+struct api_msg_msg {
+  /** The netconn which to process - always needed: it includes the semaphore
+      which is used to block the application thread until the function finished. */
+  struct netconn *conn;
+  /** The return value of the function executed in tcpip_thread. */
+  err_t err;
+  /** Depending on the executed function, one of these union members is used */
+  union {
+    /** used for do_send */
+    struct netbuf *b;
+    /** used for do_newconn */
+    struct {
+      u8_t proto;
+    } n;
+    /** used for do_bind and do_connect */
+    struct {
+      ip_addr_t *ipaddr;
+      u16_t port;
+    } bc;
+    /** used for do_getaddr */
+    struct {
+      ip_addr_t *ipaddr;
+      u16_t *port;
+      u8_t local;
+    } ad;
+    /** used for do_write */
+    struct {
+      const void *dataptr;
+      size_t len;
+      u8_t apiflags;
+    } w;
+    /** used for do_recv */
+    struct {
+      u32_t len;
+    } r;
+    /** used for do_close (/shutdown) */
+    struct {
+      u8_t shut;
+    } sd;
+#if LWIP_IGMP
+    /** used for do_join_leave_group */
+    struct {
+      ip_addr_t *multiaddr;
+      ip_addr_t *netif_addr;
+      enum netconn_igmp join_or_leave;
+    } jl;
+#endif /* LWIP_IGMP */
+#if TCP_LISTEN_BACKLOG
+    struct {
+      u8_t backlog;
+    } lb;
+#endif /* TCP_LISTEN_BACKLOG */
+  } msg;
+};
+
+/** This struct contains a function to execute in another thread context and
+    a struct api_msg_msg that serves as an argument for this function.
+    This is passed to tcpip_apimsg to execute functions in tcpip_thread context. */
+struct api_msg {
+  /** function to execute in tcpip_thread context */
+  void (* function)(struct api_msg_msg *msg);
+  /** arguments for this function */
+  struct api_msg_msg msg;
+};
+
+#if LWIP_DNS
+/** As do_gethostbyname requires more arguments but doesn't require a netconn,
+    it has its own struct (to avoid struct api_msg getting bigger than necessary).
+    do_gethostbyname must be called using tcpip_callback instead of tcpip_apimsg
+    (see netconn_gethostbyname). */
+struct dns_api_msg {
+  /** Hostname to query or dotted IP address string */
+  const char *name;
+  /** Rhe resolved address is stored here */
+  ip_addr_t *addr;
+  /** This semaphore is posted when the name is resolved, the application thread
+      should wait on it. */
+  sys_sem_t *sem;
+  /** Errors are given back here */
+  err_t *err;
+};
+#endif /* LWIP_DNS */
+
+void do_newconn         ( struct api_msg_msg *msg);
+void do_delconn         ( struct api_msg_msg *msg);
+void do_bind            ( struct api_msg_msg *msg);
+void do_connect         ( struct api_msg_msg *msg);
+void do_disconnect      ( struct api_msg_msg *msg);
+void do_listen          ( struct api_msg_msg *msg);
+void do_send            ( struct api_msg_msg *msg);
+void do_recv            ( struct api_msg_msg *msg);
+void do_write           ( struct api_msg_msg *msg);
+void do_getaddr         ( struct api_msg_msg *msg);
+void do_close           ( struct api_msg_msg *msg);
+void do_shutdown        ( struct api_msg_msg *msg);
+#if LWIP_IGMP
+void do_join_leave_group( struct api_msg_msg *msg);
+#endif /* LWIP_IGMP */
+
+#if LWIP_DNS
+void do_gethostbyname(void *arg);
+#endif /* LWIP_DNS */
+
+struct netconn* netconn_alloc(enum netconn_type t, netconn_callback callback);
+void netconn_free(struct netconn *conn);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_NETCONN */
+
+#endif /* __LWIP_API_MSG_H__ */
diff --git a/core/lwip/src/include/lwip/arch.h b/core/lwip/src/include/lwip/arch.h
new file mode 100644
index 00000000..524af6be
--- /dev/null
+++ b/core/lwip/src/include/lwip/arch.h
@@ -0,0 +1,238 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_ARCH_H__
+#define __LWIP_ARCH_H__
+
+#ifndef LITTLE_ENDIAN
+#define LITTLE_ENDIAN 1234
+#endif
+
+#ifndef BIG_ENDIAN
+#define BIG_ENDIAN 4321
+#endif
+
+#include "arch/cc.h"
+
+/** Temporary: define format string for size_t if not defined in cc.h */
+#ifndef SZT_F
+#define SZT_F U32_F
+#endif /* SZT_F */
+/** Temporary upgrade helper: define format string for u8_t as hex if not
+    defined in cc.h */
+#ifndef X8_F
+#define X8_F  "02x"
+#endif /* X8_F */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef PACK_STRUCT_BEGIN
+#define PACK_STRUCT_BEGIN
+#endif /* PACK_STRUCT_BEGIN */
+
+#ifndef PACK_STRUCT_END
+#define PACK_STRUCT_END
+#endif /* PACK_STRUCT_END */
+
+#ifndef PACK_STRUCT_FIELD
+#define PACK_STRUCT_FIELD(x) x
+#endif /* PACK_STRUCT_FIELD */
+
+
+#ifndef LWIP_UNUSED_ARG
+#define LWIP_UNUSED_ARG(x) (void)x
+#endif /* LWIP_UNUSED_ARG */ 
+
+
+#ifdef LWIP_PROVIDE_ERRNO
+
+#define  EPERM         1  /* Operation not permitted */
+#define  ENOENT        2  /* No such file or directory */
+#define  ESRCH         3  /* No such process */
+#define  EINTR         4  /* Interrupted system call */
+#define  EIO           5  /* I/O error */
+#define  ENXIO         6  /* No such device or address */
+#define  E2BIG         7  /* Arg list too long */
+#define  ENOEXEC       8  /* Exec format error */
+#define  EBADF         9  /* Bad file number */
+#define  ECHILD       10  /* No child processes */
+#define  EAGAIN       11  /* Try again */
+#define  ENOMEM       12  /* Out of memory */
+#define  EACCES       13  /* Permission denied */
+#define  EFAULT       14  /* Bad address */
+#define  ENOTBLK      15  /* Block device required */
+#define  EBUSY        16  /* Device or resource busy */
+#define  EEXIST       17  /* File exists */
+#define  EXDEV        18  /* Cross-device link */
+#define  ENODEV       19  /* No such device */
+#define  ENOTDIR      20  /* Not a directory */
+#define  EISDIR       21  /* Is a directory */
+#define  EINVAL       22  /* Invalid argument */
+#define  ENFILE       23  /* File table overflow */
+#define  EMFILE       24  /* Too many open files */
+#define  ENOTTY       25  /* Not a typewriter */
+#define  ETXTBSY      26  /* Text file busy */
+#define  EFBIG        27  /* File too large */
+#define  ENOSPC       28  /* No space left on device */
+#define  ESPIPE       29  /* Illegal seek */
+#define  EROFS        30  /* Read-only file system */
+#define  EMLINK       31  /* Too many links */
+#define  EPIPE        32  /* Broken pipe */
+#define  EDOM         33  /* Math argument out of domain of func */
+#define  ERANGE       34  /* Math result not representable */
+#define  EDEADLK      35  /* Resource deadlock would occur */
+#define  ENAMETOOLONG 36  /* File name too long */
+#define  ENOLCK       37  /* No record locks available */
+#define  ENOSYS       38  /* Function not implemented */
+#define  ENOTEMPTY    39  /* Directory not empty */
+#define  ELOOP        40  /* Too many symbolic links encountered */
+#define  EWOULDBLOCK  EAGAIN  /* Operation would block */
+#define  ENOMSG       42  /* No message of desired type */
+#define  EIDRM        43  /* Identifier removed */
+#define  ECHRNG       44  /* Channel number out of range */
+#define  EL2NSYNC     45  /* Level 2 not synchronized */
+#define  EL3HLT       46  /* Level 3 halted */
+#define  EL3RST       47  /* Level 3 reset */
+#define  ELNRNG       48  /* Link number out of range */
+#define  EUNATCH      49  /* Protocol driver not attached */
+#define  ENOCSI       50  /* No CSI structure available */
+#define  EL2HLT       51  /* Level 2 halted */
+#define  EBADE        52  /* Invalid exchange */
+#define  EBADR        53  /* Invalid request descriptor */
+#define  EXFULL       54  /* Exchange full */
+#define  ENOANO       55  /* No anode */
+#define  EBADRQC      56  /* Invalid request code */
+#define  EBADSLT      57  /* Invalid slot */
+
+#define  EDEADLOCK    EDEADLK
+
+#define  EBFONT       59  /* Bad font file format */
+#define  ENOSTR       60  /* Device not a stream */
+#define  ENODATA      61  /* No data available */
+#define  ETIME        62  /* Timer expired */
+#define  ENOSR        63  /* Out of streams resources */
+#define  ENONET       64  /* Machine is not on the network */
+#define  ENOPKG       65  /* Package not installed */
+#define  EREMOTE      66  /* Object is remote */
+#define  ENOLINK      67  /* Link has been severed */
+#define  EADV         68  /* Advertise error */
+#define  ESRMNT       69  /* Srmount error */
+#define  ECOMM        70  /* Communication error on send */
+#define  EPROTO       71  /* Protocol error */
+#define  EMULTIHOP    72  /* Multihop attempted */
+#define  EDOTDOT      73  /* RFS specific error */
+#define  EBADMSG      74  /* Not a data message */
+#define  EOVERFLOW    75  /* Value too large for defined data type */
+#define  ENOTUNIQ     76  /* Name not unique on network */
+#define  EBADFD       77  /* File descriptor in bad state */
+#define  EREMCHG      78  /* Remote address changed */
+#define  ELIBACC      79  /* Can not access a needed shared library */
+#define  ELIBBAD      80  /* Accessing a corrupted shared library */
+#define  ELIBSCN      81  /* .lib section in a.out corrupted */
+#define  ELIBMAX      82  /* Attempting to link in too many shared libraries */
+#define  ELIBEXEC     83  /* Cannot exec a shared library directly */
+#define  EILSEQ       84  /* Illegal byte sequence */
+#define  ERESTART     85  /* Interrupted system call should be restarted */
+#define  ESTRPIPE     86  /* Streams pipe error */
+#define  EUSERS       87  /* Too many users */
+#define  ENOTSOCK     88  /* Socket operation on non-socket */
+#define  EDESTADDRREQ 89  /* Destination address required */
+#define  EMSGSIZE     90  /* Message too long */
+#define  EPROTOTYPE   91  /* Protocol wrong type for socket */
+#define  ENOPROTOOPT  92  /* Protocol not available */
+#define  EPROTONOSUPPORT 93  /* Protocol not supported */
+#define  ESOCKTNOSUPPORT 94  /* Socket type not supported */
+#define  EOPNOTSUPP      95  /* Operation not supported on transport endpoint */
+#define  EPFNOSUPPORT    96  /* Protocol family not supported */
+#define  EAFNOSUPPORT    97  /* Address family not supported by protocol */
+#define  EADDRINUSE      98  /* Address already in use */
+#define  EADDRNOTAVAIL   99  /* Cannot assign requested address */
+#define  ENETDOWN       100  /* Network is down */
+#define  ENETUNREACH    101  /* Network is unreachable */
+#define  ENETRESET      102  /* Network dropped connection because of reset */
+#define  ECONNABORTED   103  /* Software caused connection abort */
+#define  ECONNRESET     104  /* Connection reset by peer */
+#define  ENOBUFS        105  /* No buffer space available */
+#define  EISCONN        106  /* Transport endpoint is already connected */
+#define  ENOTCONN       107  /* Transport endpoint is not connected */
+#define  ESHUTDOWN      108  /* Cannot send after transport endpoint shutdown */
+#define  ETOOMANYREFS   109  /* Too many references: cannot splice */
+#define  ETIMEDOUT      110  /* Connection timed out */
+#define  ECONNREFUSED   111  /* Connection refused */
+#define  EHOSTDOWN      112  /* Host is down */
+#define  EHOSTUNREACH   113  /* No route to host */
+#define  EALREADY       114  /* Operation already in progress */
+#define  EINPROGRESS    115  /* Operation now in progress */
+#define  ESTALE         116  /* Stale NFS file handle */
+#define  EUCLEAN        117  /* Structure needs cleaning */
+#define  ENOTNAM        118  /* Not a XENIX named type file */
+#define  ENAVAIL        119  /* No XENIX semaphores available */
+#define  EISNAM         120  /* Is a named type file */
+#define  EREMOTEIO      121  /* Remote I/O error */
+#define  EDQUOT         122  /* Quota exceeded */
+
+#define  ENOMEDIUM      123  /* No medium found */
+#define  EMEDIUMTYPE    124  /* Wrong medium type */
+
+
+#define ENSROK                    0 /* DNS server returned answer with no data */
+#define ENSRNODATA              160 /* DNS server returned answer with no data */
+#define ENSRFORMERR             161 /* DNS server claims query was misformatted */
+#define ENSRSERVFAIL            162 /* DNS server returned general failure */
+#define ENSRNOTFOUND            163 /* Domain name not found */
+#define ENSRNOTIMP              164 /* DNS server does not implement requested operation */
+#define ENSRREFUSED             165 /* DNS server refused query */
+#define ENSRBADQUERY            166 /* Misformatted DNS query */
+#define ENSRBADNAME             167 /* Misformatted domain name */
+#define ENSRBADFAMILY           168 /* Unsupported address family */
+#define ENSRBADRESP             169 /* Misformatted DNS reply */
+#define ENSRCONNREFUSED         170 /* Could not contact DNS servers */
+#define ENSRTIMEOUT             171 /* Timeout while contacting DNS servers */
+#define ENSROF                  172 /* End of file */
+#define ENSRFILE                173 /* Error reading file */
+#define ENSRNOMEM               174 /* Out of memory */
+#define ENSRDESTRUCTION         175 /* Application terminated lookup */
+#define ENSRQUERYDOMAINTOOLONG  176 /* Domain name is too long */
+#define ENSRCNAMELOOP           177 /* Domain name is too long */
+
+#ifndef errno
+extern int errno;
+#endif
+
+#endif /* LWIP_PROVIDE_ERRNO */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_ARCH_H__ */
diff --git a/core/lwip/src/include/lwip/debug.h b/core/lwip/src/include/lwip/debug.h
new file mode 100644
index 00000000..d8359ea3
--- /dev/null
+++ b/core/lwip/src/include/lwip/debug.h
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_DEBUG_H__
+#define __LWIP_DEBUG_H__
+
+#include "lwip/arch.h"
+
+/** lower two bits indicate debug level
+ * - 0 all
+ * - 1 warning
+ * - 2 serious
+ * - 3 severe
+ */
+#define LWIP_DBG_LEVEL_ALL     0x00
+#define LWIP_DBG_LEVEL_OFF     LWIP_DBG_LEVEL_ALL /* compatibility define only */
+#define LWIP_DBG_LEVEL_WARNING 0x01 /* bad checksums, dropped packets, ... */
+#define LWIP_DBG_LEVEL_SERIOUS 0x02 /* memory allocation failures, ... */
+#define LWIP_DBG_LEVEL_SEVERE  0x03
+#define LWIP_DBG_MASK_LEVEL    0x03
+
+/** flag for LWIP_DEBUGF to enable that debug message */
+#define LWIP_DBG_ON            0x80U
+/** flag for LWIP_DEBUGF to disable that debug message */
+#define LWIP_DBG_OFF           0x00U
+
+/** flag for LWIP_DEBUGF indicating a tracing message (to follow program flow) */
+#define LWIP_DBG_TRACE         0x40U
+/** flag for LWIP_DEBUGF indicating a state debug message (to follow module states) */
+#define LWIP_DBG_STATE         0x20U
+/** flag for LWIP_DEBUGF indicating newly added code, not thoroughly tested yet */
+#define LWIP_DBG_FRESH         0x10U
+/** flag for LWIP_DEBUGF to halt after printing this debug message */
+#define LWIP_DBG_HALT          0x08U
+
+#ifndef LWIP_NOASSERT
+#define LWIP_ASSERT(message, assertion) do { if(!(assertion)) \
+  LWIP_PLATFORM_ASSERT(message); } while(0)
+#else  /* LWIP_NOASSERT */
+#define LWIP_ASSERT(message, assertion) 
+#endif /* LWIP_NOASSERT */
+
+/** if "expression" isn't true, then print "message" and execute "handler" expression */
+#ifndef LWIP_ERROR
+#define LWIP_ERROR(message, expression, handler) do { if (!(expression)) { \
+  LWIP_PLATFORM_ASSERT(message); handler;}} while(0)
+#endif /* LWIP_ERROR */
+
+#ifdef LWIP_DEBUG
+/** print debug message only if debug message type is enabled...
+ *  AND is of correct type AND is at least LWIP_DBG_LEVEL
+ */
+#define LWIP_DEBUGF(debug, message) do { \
+                               if ( \
+                                   ((debug) & LWIP_DBG_ON) && \
+                                   ((debug) & LWIP_DBG_TYPES_ON) && \
+                                   ((s16_t)((debug) & LWIP_DBG_MASK_LEVEL) >= LWIP_DBG_MIN_LEVEL)) { \
+                                 LWIP_PLATFORM_DIAG(message); \
+                                 if ((debug) & LWIP_DBG_HALT) { \
+                                   while(1); \
+                                 } \
+                               } \
+                             } while(0)
+
+#else  /* LWIP_DEBUG */
+#define LWIP_DEBUGF(debug, message) 
+#endif /* LWIP_DEBUG */
+
+#endif /* __LWIP_DEBUG_H__ */
+
diff --git a/core/lwip/src/include/lwip/def.h b/core/lwip/src/include/lwip/def.h
new file mode 100644
index 00000000..9b6de6a8
--- /dev/null
+++ b/core/lwip/src/include/lwip/def.h
@@ -0,0 +1,127 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_DEF_H__
+#define __LWIP_DEF_H__
+
+/* arch.h might define NULL already */
+#include "lwip/arch.h"
+#include "lwip/opt.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define LWIP_MAX(x , y)  (((x) > (y)) ? (x) : (y))
+#define LWIP_MIN(x , y)  (((x) < (y)) ? (x) : (y))
+
+#ifndef NULL
+#define NULL ((void *)0)
+#endif
+
+/** Get the absolute difference between 2 u32_t values (correcting overflows)
+ * 'a' is expected to be 'higher' (without overflow) than 'b'. */
+#define LWIP_U32_DIFF(a, b) (((a) >= (b)) ? ((a) - (b)) : (((a) + ((b) ^ 0xFFFFFFFF) + 1))) 
+
+/* Endianess-optimized shifting of two u8_t to create one u16_t */
+#if BYTE_ORDER == LITTLE_ENDIAN
+#define LWIP_MAKE_U16(a, b) ((a << 8) | b)
+#else
+#define LWIP_MAKE_U16(a, b) ((b << 8) | a)
+#endif 
+
+#ifndef LWIP_PLATFORM_BYTESWAP
+#define LWIP_PLATFORM_BYTESWAP 0
+#endif
+
+#ifndef LWIP_PREFIX_BYTEORDER_FUNCS
+/* workaround for naming collisions on some platforms */
+
+#ifdef htons
+#undef htons
+#endif /* htons */
+#ifdef htonl
+#undef htonl
+#endif /* htonl */
+#ifdef ntohs
+#undef ntohs
+#endif /* ntohs */
+#ifdef ntohl
+#undef ntohl
+#endif /* ntohl */
+
+#define htons(x) lwip_htons(x)
+#define ntohs(x) lwip_ntohs(x)
+#define htonl(x) lwip_htonl(x)
+#define ntohl(x) lwip_ntohl(x)
+#endif /* LWIP_PREFIX_BYTEORDER_FUNCS */
+
+#if BYTE_ORDER == BIG_ENDIAN
+#define lwip_htons(x) (x)
+#define lwip_ntohs(x) (x)
+#define lwip_htonl(x) (x)
+#define lwip_ntohl(x) (x)
+#define PP_HTONS(x) (x)
+#define PP_NTOHS(x) (x)
+#define PP_HTONL(x) (x)
+#define PP_NTOHL(x) (x)
+#else /* BYTE_ORDER != BIG_ENDIAN */
+#if LWIP_PLATFORM_BYTESWAP
+#define lwip_htons(x) LWIP_PLATFORM_HTONS(x)
+#define lwip_ntohs(x) LWIP_PLATFORM_HTONS(x)
+#define lwip_htonl(x) LWIP_PLATFORM_HTONL(x)
+#define lwip_ntohl(x) LWIP_PLATFORM_HTONL(x)
+#else /* LWIP_PLATFORM_BYTESWAP */
+u16_t lwip_htons(u16_t x);
+u16_t lwip_ntohs(u16_t x);
+u32_t lwip_htonl(u32_t x);
+u32_t lwip_ntohl(u32_t x);
+#endif /* LWIP_PLATFORM_BYTESWAP */
+
+/* These macros should be calculated by the preprocessor and are used
+   with compile-time constants only (so that there is no little-endian
+   overhead at runtime). */
+#define PP_HTONS(x) ((((x) & 0xff) << 8) | (((x) & 0xff00) >> 8))
+#define PP_NTOHS(x) PP_HTONS(x)
+#define PP_HTONL(x) ((((x) & 0xff) << 24) | \
+                     (((x) & 0xff00) << 8) | \
+                     (((x) & 0xff0000UL) >> 8) | \
+                     (((x) & 0xff000000UL) >> 24))
+#define PP_NTOHL(x) PP_HTONL(x)
+
+#endif /* BYTE_ORDER == BIG_ENDIAN */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_DEF_H__ */
+
diff --git a/core/lwip/src/include/lwip/dhcp.h b/core/lwip/src/include/lwip/dhcp.h
new file mode 100644
index 00000000..32d93381
--- /dev/null
+++ b/core/lwip/src/include/lwip/dhcp.h
@@ -0,0 +1,242 @@
+/** @file
+ */
+
+#ifndef __LWIP_DHCP_H__
+#define __LWIP_DHCP_H__
+
+#include "lwip/opt.h"
+
+#if LWIP_DHCP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/netif.h"
+#include "lwip/udp.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** period (in seconds) of the application calling dhcp_coarse_tmr() */
+#define DHCP_COARSE_TIMER_SECS 60 
+/** period (in milliseconds) of the application calling dhcp_coarse_tmr() */
+#define DHCP_COARSE_TIMER_MSECS (DHCP_COARSE_TIMER_SECS * 1000UL)
+/** period (in milliseconds) of the application calling dhcp_fine_tmr() */
+#define DHCP_FINE_TIMER_MSECS 500 
+
+#define DHCP_CHADDR_LEN 16U
+#define DHCP_SNAME_LEN  64U
+#define DHCP_FILE_LEN   128U
+
+struct dhcp
+{
+  /** transaction identifier of last sent request */ 
+  u32_t xid;
+  /** our connection to the DHCP server */ 
+  struct udp_pcb *pcb;
+  /** incoming msg */
+  struct dhcp_msg *msg_in;
+  /** current DHCP state machine state */
+  u8_t state;
+  /** retries of current request */
+  u8_t tries;
+#if LWIP_DHCP_AUTOIP_COOP
+  u8_t autoip_coop_state;
+#endif
+  u8_t subnet_mask_given;
+
+  struct pbuf *p_out; /* pbuf of outcoming msg */
+  struct dhcp_msg *msg_out; /* outgoing msg */
+  u16_t options_out_len; /* outgoing msg options length */
+  u16_t request_timeout; /* #ticks with period DHCP_FINE_TIMER_SECS for request timeout */
+  u16_t t1_timeout;  /* #ticks with period DHCP_COARSE_TIMER_SECS for renewal time */
+  u16_t t2_timeout;  /* #ticks with period DHCP_COARSE_TIMER_SECS for rebind time */
+  ip_addr_t server_ip_addr; /* dhcp server address that offered this lease */
+  ip_addr_t offered_ip_addr;
+  ip_addr_t offered_sn_mask;
+  ip_addr_t offered_gw_addr;
+ 
+  u32_t offered_t0_lease; /* lease period (in seconds) */
+  u32_t offered_t1_renew; /* recommended renew time (usually 50% of lease period) */
+  u32_t offered_t2_rebind; /* recommended rebind time (usually 66% of lease period)  */
+  /* @todo: LWIP_DHCP_BOOTP_FILE configuration option?
+     integrate with possible TFTP-client for booting? */
+#if LWIP_DHCP_BOOTP_FILE
+  ip_addr_t offered_si_addr;
+  char boot_file_name[DHCP_FILE_LEN];
+#endif /* LWIP_DHCP_BOOTPFILE */
+};
+
+/* MUST be compiled with "pack structs" or equivalent! */
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+/** minimum set of fields of any DHCP message */
+struct dhcp_msg
+{
+  PACK_STRUCT_FIELD(u8_t op);
+  PACK_STRUCT_FIELD(u8_t htype);
+  PACK_STRUCT_FIELD(u8_t hlen);
+  PACK_STRUCT_FIELD(u8_t hops);
+  PACK_STRUCT_FIELD(u32_t xid);
+  PACK_STRUCT_FIELD(u16_t secs);
+  PACK_STRUCT_FIELD(u16_t flags);
+  PACK_STRUCT_FIELD(ip_addr_p_t ciaddr);
+  PACK_STRUCT_FIELD(ip_addr_p_t yiaddr);
+  PACK_STRUCT_FIELD(ip_addr_p_t siaddr);
+  PACK_STRUCT_FIELD(ip_addr_p_t giaddr);
+  PACK_STRUCT_FIELD(u8_t chaddr[DHCP_CHADDR_LEN]);
+  PACK_STRUCT_FIELD(u8_t sname[DHCP_SNAME_LEN]);
+  PACK_STRUCT_FIELD(u8_t file[DHCP_FILE_LEN]);
+  PACK_STRUCT_FIELD(u32_t cookie);
+#define DHCP_MIN_OPTIONS_LEN 68U
+/** make sure user does not configure this too small */
+#if ((defined(DHCP_OPTIONS_LEN)) && (DHCP_OPTIONS_LEN < DHCP_MIN_OPTIONS_LEN))
+#  undef DHCP_OPTIONS_LEN
+#endif
+/** allow this to be configured in lwipopts.h, but not too small */
+#if (!defined(DHCP_OPTIONS_LEN))
+/** set this to be sufficient for your options in outgoing DHCP msgs */
+#  define DHCP_OPTIONS_LEN DHCP_MIN_OPTIONS_LEN
+#endif
+  PACK_STRUCT_FIELD(u8_t options[DHCP_OPTIONS_LEN]);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+void dhcp_set_struct(struct netif *netif, struct dhcp *dhcp);
+/** Remove a struct dhcp previously set to the netif using dhcp_set_struct() */
+#define dhcp_remove_struct(netif) do { (netif)->dhcp = NULL; } while(0)
+void dhcp_cleanup(struct netif *netif);
+/** start DHCP configuration */
+err_t dhcp_start(struct netif *netif);
+/** enforce early lease renewal (not needed normally)*/
+err_t dhcp_renew(struct netif *netif);
+/** release the DHCP lease, usually called before dhcp_stop()*/
+err_t dhcp_release(struct netif *netif);
+/** stop DHCP configuration */
+void dhcp_stop(struct netif *netif);
+/** inform server of our manual IP address */
+void dhcp_inform(struct netif *netif);
+/** Handle a possible change in the network configuration */
+void dhcp_network_changed(struct netif *netif);
+
+/** if enabled, check whether the offered IP address is not in use, using ARP */
+#if DHCP_DOES_ARP_CHECK
+void dhcp_arp_reply(struct netif *netif, ip_addr_t *addr);
+#endif
+
+/** to be called every minute */
+void dhcp_coarse_tmr(void);
+/** to be called every half second */
+void dhcp_fine_tmr(void);
+ 
+/** DHCP message item offsets and length */
+#define DHCP_OP_OFS       0
+#define DHCP_HTYPE_OFS    1
+#define DHCP_HLEN_OFS     2
+#define DHCP_HOPS_OFS     3
+#define DHCP_XID_OFS      4
+#define DHCP_SECS_OFS     8
+#define DHCP_FLAGS_OFS    10
+#define DHCP_CIADDR_OFS   12
+#define DHCP_YIADDR_OFS   16
+#define DHCP_SIADDR_OFS   20
+#define DHCP_GIADDR_OFS   24
+#define DHCP_CHADDR_OFS   28
+#define DHCP_SNAME_OFS    44
+#define DHCP_FILE_OFS     108
+#define DHCP_MSG_LEN      236
+
+#define DHCP_COOKIE_OFS   DHCP_MSG_LEN
+#define DHCP_OPTIONS_OFS  (DHCP_MSG_LEN + 4)
+
+#define DHCP_CLIENT_PORT  68  
+#define DHCP_SERVER_PORT  67
+
+/** DHCP client states */
+#define DHCP_OFF          0
+#define DHCP_REQUESTING   1
+#define DHCP_INIT         2
+#define DHCP_REBOOTING    3
+#define DHCP_REBINDING    4
+#define DHCP_RENEWING     5
+#define DHCP_SELECTING    6
+#define DHCP_INFORMING    7
+#define DHCP_CHECKING     8
+#define DHCP_PERMANENT    9
+#define DHCP_BOUND        10
+/** not yet implemented #define DHCP_RELEASING 11 */
+#define DHCP_BACKING_OFF  12
+
+/** AUTOIP cooperatation flags */
+#define DHCP_AUTOIP_COOP_STATE_OFF  0
+#define DHCP_AUTOIP_COOP_STATE_ON   1
+ 
+#define DHCP_BOOTREQUEST  1
+#define DHCP_BOOTREPLY    2
+
+/** DHCP message types */
+#define DHCP_DISCOVER 1
+#define DHCP_OFFER    2
+#define DHCP_REQUEST  3
+#define DHCP_DECLINE  4
+#define DHCP_ACK      5
+#define DHCP_NAK      6
+#define DHCP_RELEASE  7
+#define DHCP_INFORM   8
+
+/** DHCP hardware type, currently only ethernet is supported */
+#define DHCP_HTYPE_ETH 1
+
+#define DHCP_MAGIC_COOKIE 0x63825363UL
+
+/* This is a list of options for BOOTP and DHCP, see RFC 2132 for descriptions */
+
+/** BootP options */
+#define DHCP_OPTION_PAD 0
+#define DHCP_OPTION_SUBNET_MASK 1 /* RFC 2132 3.3 */
+#define DHCP_OPTION_ROUTER 3
+#define DHCP_OPTION_DNS_SERVER 6 
+#define DHCP_OPTION_HOSTNAME 12
+#define DHCP_OPTION_IP_TTL 23
+#define DHCP_OPTION_MTU 26
+#define DHCP_OPTION_BROADCAST 28
+#define DHCP_OPTION_TCP_TTL 37
+#define DHCP_OPTION_END 255
+
+/** DHCP options */
+#define DHCP_OPTION_REQUESTED_IP 50 /* RFC 2132 9.1, requested IP address */
+#define DHCP_OPTION_LEASE_TIME 51 /* RFC 2132 9.2, time in seconds, in 4 bytes */
+#define DHCP_OPTION_OVERLOAD 52 /* RFC2132 9.3, use file and/or sname field for options */
+
+#define DHCP_OPTION_MESSAGE_TYPE 53 /* RFC 2132 9.6, important for DHCP */
+#define DHCP_OPTION_MESSAGE_TYPE_LEN 1
+
+#define DHCP_OPTION_SERVER_ID 54 /* RFC 2132 9.7, server IP address */
+#define DHCP_OPTION_PARAMETER_REQUEST_LIST 55 /* RFC 2132 9.8, requested option types */
+
+#define DHCP_OPTION_MAX_MSG_SIZE 57 /* RFC 2132 9.10, message size accepted >= 576 */
+#define DHCP_OPTION_MAX_MSG_SIZE_LEN 2
+
+#define DHCP_OPTION_T1 58 /* T1 renewal time */
+#define DHCP_OPTION_T2 59 /* T2 rebinding time */
+#define DHCP_OPTION_US 60
+#define DHCP_OPTION_CLIENT_ID 61
+#define DHCP_OPTION_TFTP_SERVERNAME 66
+#define DHCP_OPTION_BOOTFILE 67
+
+/** possible combinations of overloading the file and sname fields with options */
+#define DHCP_OVERLOAD_NONE 0
+#define DHCP_OVERLOAD_FILE 1
+#define DHCP_OVERLOAD_SNAME  2
+#define DHCP_OVERLOAD_SNAME_FILE 3
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_DHCP */
+
+#endif /*__LWIP_DHCP_H__*/
diff --git a/core/lwip/src/include/lwip/dns.h b/core/lwip/src/include/lwip/dns.h
new file mode 100644
index 00000000..6c7d9b07
--- /dev/null
+++ b/core/lwip/src/include/lwip/dns.h
@@ -0,0 +1,124 @@
+/**
+ * lwip DNS resolver header file.
+
+ * Author: Jim Pettinato 
+ *   April 2007
+
+ * ported from uIP resolv.c Copyright (c) 2002-2003, Adam Dunkels.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote
+ *    products derived from this software without specific prior
+ *    written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
+ * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
+ * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __LWIP_DNS_H__
+#define __LWIP_DNS_H__
+
+#include "lwip/opt.h"
+
+#if LWIP_DNS /* don't build if not configured for use in lwipopts.h */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** DNS timer period */
+#define DNS_TMR_INTERVAL          1000
+
+/** DNS field TYPE used for "Resource Records" */
+#define DNS_RRTYPE_A              1     /* a host address */
+#define DNS_RRTYPE_NS             2     /* an authoritative name server */
+#define DNS_RRTYPE_MD             3     /* a mail destination (Obsolete - use MX) */
+#define DNS_RRTYPE_MF             4     /* a mail forwarder (Obsolete - use MX) */
+#define DNS_RRTYPE_CNAME          5     /* the canonical name for an alias */
+#define DNS_RRTYPE_SOA            6     /* marks the start of a zone of authority */
+#define DNS_RRTYPE_MB             7     /* a mailbox domain name (EXPERIMENTAL) */
+#define DNS_RRTYPE_MG             8     /* a mail group member (EXPERIMENTAL) */
+#define DNS_RRTYPE_MR             9     /* a mail rename domain name (EXPERIMENTAL) */
+#define DNS_RRTYPE_NULL           10    /* a null RR (EXPERIMENTAL) */
+#define DNS_RRTYPE_WKS            11    /* a well known service description */
+#define DNS_RRTYPE_PTR            12    /* a domain name pointer */
+#define DNS_RRTYPE_HINFO          13    /* host information */
+#define DNS_RRTYPE_MINFO          14    /* mailbox or mail list information */
+#define DNS_RRTYPE_MX             15    /* mail exchange */
+#define DNS_RRTYPE_TXT            16    /* text strings */
+
+/** DNS field CLASS used for "Resource Records" */
+#define DNS_RRCLASS_IN            1     /* the Internet */
+#define DNS_RRCLASS_CS            2     /* the CSNET class (Obsolete - used only for examples in some obsolete RFCs) */
+#define DNS_RRCLASS_CH            3     /* the CHAOS class */
+#define DNS_RRCLASS_HS            4     /* Hesiod [Dyer 87] */
+#define DNS_RRCLASS_FLUSH         0x800 /* Flush bit */
+
+/* The size used for the next line is rather a hack, but it prevents including socket.h in all files
+   that include memp.h, and that would possibly break portability (since socket.h defines some types
+   and constants possibly already define by the OS).
+   Calculation rule:
+   sizeof(struct addrinfo) + sizeof(struct sockaddr_in) + DNS_MAX_NAME_LENGTH + 1 byte zero-termination */
+#define NETDB_ELEM_SIZE           (32 + 16 + DNS_MAX_NAME_LENGTH + 1)
+
+#if DNS_LOCAL_HOSTLIST
+/** struct used for local host-list */
+struct local_hostlist_entry {
+  /** static hostname */
+  const char *name;
+  /** static host address in network byteorder */
+  ip_addr_t addr;
+  struct local_hostlist_entry *next;
+};
+#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
+#ifndef DNS_LOCAL_HOSTLIST_MAX_NAMELEN
+#define DNS_LOCAL_HOSTLIST_MAX_NAMELEN  DNS_MAX_NAME_LENGTH
+#endif
+#define LOCALHOSTLIST_ELEM_SIZE ((sizeof(struct local_hostlist_entry) + DNS_LOCAL_HOSTLIST_MAX_NAMELEN + 1))
+#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
+#endif /* DNS_LOCAL_HOSTLIST */
+
+/** Callback which is invoked when a hostname is found.
+ * A function of this type must be implemented by the application using the DNS resolver.
+ * @param name pointer to the name that was looked up.
+ * @param ipaddr pointer to an ip_addr_t containing the IP address of the hostname,
+ *        or NULL if the name could not be found (or on any other error).
+ * @param callback_arg a user-specified callback argument passed to dns_gethostbyname
+*/
+typedef void (*dns_found_callback)(const char *name, ip_addr_t *ipaddr, void *callback_arg);
+
+void           dns_init(void);
+void           dns_tmr(void);
+void           dns_setserver(u8_t numdns, ip_addr_t *dnsserver);
+ip_addr_t      dns_getserver(u8_t numdns);
+err_t          dns_gethostbyname(const char *hostname, ip_addr_t *addr,
+                                 dns_found_callback found, void *callback_arg);
+
+#if DNS_LOCAL_HOSTLIST && DNS_LOCAL_HOSTLIST_IS_DYNAMIC
+int            dns_local_removehost(const char *hostname, const ip_addr_t *addr);
+err_t          dns_local_addhost(const char *hostname, const ip_addr_t *addr);
+#endif /* DNS_LOCAL_HOSTLIST && DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_DNS */
+
+#endif /* __LWIP_DNS_H__ */
diff --git a/core/lwip/src/include/lwip/err.h b/core/lwip/src/include/lwip/err.h
new file mode 100644
index 00000000..ac907729
--- /dev/null
+++ b/core/lwip/src/include/lwip/err.h
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_ERR_H__
+#define __LWIP_ERR_H__
+
+#include "lwip/opt.h"
+#include "lwip/arch.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** Define LWIP_ERR_T in cc.h if you want to use
+ *  a different type for your platform (must be signed). */
+#ifdef LWIP_ERR_T
+typedef LWIP_ERR_T err_t;
+#else /* LWIP_ERR_T */
+typedef s8_t err_t;
+#endif /* LWIP_ERR_T*/
+
+/* Definitions for error constants. */
+
+#define ERR_OK          0    /* No error, everything OK. */
+#define ERR_MEM        -1    /* Out of memory error.     */
+#define ERR_BUF        -2    /* Buffer error.            */
+#define ERR_TIMEOUT    -3    /* Timeout.                 */
+#define ERR_RTE        -4    /* Routing problem.         */
+#define ERR_INPROGRESS -5    /* Operation in progress    */
+#define ERR_VAL        -6    /* Illegal value.           */
+#define ERR_WOULDBLOCK -7    /* Operation would block.   */
+#define ERR_USE        -8    /* Address in use.          */
+#define ERR_ISCONN     -9    /* Already connected.       */
+
+#define ERR_IS_FATAL(e) ((e) < ERR_ISCONN)
+
+#define ERR_ABRT       -10   /* Connection aborted.      */
+#define ERR_RST        -11   /* Connection reset.        */
+#define ERR_CLSD       -12   /* Connection closed.       */
+#define ERR_CONN       -13   /* Not connected.           */
+
+#define ERR_ARG        -14   /* Illegal argument.        */
+
+#define ERR_IF         -15   /* Low-level netif error    */
+
+
+#ifdef LWIP_DEBUG
+extern const char *lwip_strerr(err_t err);
+#else
+#define lwip_strerr(x) ""
+#endif /* LWIP_DEBUG */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_ERR_H__ */
diff --git a/core/lwip/src/include/lwip/init.h b/core/lwip/src/include/lwip/init.h
new file mode 100644
index 00000000..77dcdfc7
--- /dev/null
+++ b/core/lwip/src/include/lwip/init.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_INIT_H__
+#define __LWIP_INIT_H__
+
+#include "lwip/opt.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** X.x.x: Major version of the stack */
+#define LWIP_VERSION_MAJOR      1U
+/** x.X.x: Minor version of the stack */
+#define LWIP_VERSION_MINOR      4U
+/** x.x.X: Revision of the stack */
+#define LWIP_VERSION_REVISION   0U
+/** For release candidates, this is set to 1..254
+  * For official releases, this is set to 255 (LWIP_RC_RELEASE)
+  * For development versions (CVS), this is set to 0 (LWIP_RC_DEVELOPMENT) */
+#define LWIP_VERSION_RC         255U
+
+/** LWIP_VERSION_RC is set to LWIP_RC_RELEASE for official releases */
+#define LWIP_RC_RELEASE         255U
+/** LWIP_VERSION_RC is set to LWIP_RC_DEVELOPMENT for CVS versions */
+#define LWIP_RC_DEVELOPMENT     0U
+
+#define LWIP_VERSION_IS_RELEASE     (LWIP_VERSION_RC == LWIP_RC_RELEASE)
+#define LWIP_VERSION_IS_DEVELOPMENT (LWIP_VERSION_RC == LWIP_RC_DEVELOPMENT)
+#define LWIP_VERSION_IS_RC          ((LWIP_VERSION_RC != LWIP_RC_RELEASE) && (LWIP_VERSION_RC != LWIP_RC_DEVELOPMENT))
+
+/** Provides the version of the stack */
+#define LWIP_VERSION   (LWIP_VERSION_MAJOR << 24   | LWIP_VERSION_MINOR << 16 | \
+                        LWIP_VERSION_REVISION << 8 | LWIP_VERSION_RC)
+
+/* Modules initialization */
+void lwip_init(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_INIT_H__ */
diff --git a/core/lwip/src/include/lwip/mem.h b/core/lwip/src/include/lwip/mem.h
new file mode 100644
index 00000000..4dbf2f64
--- /dev/null
+++ b/core/lwip/src/include/lwip/mem.h
@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_MEM_H__
+#define __LWIP_MEM_H__
+
+#include "lwip/opt.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if MEM_LIBC_MALLOC
+
+#include <stddef.h> /* for size_t */
+
+typedef size_t mem_size_t;
+
+/* aliases for C library malloc() */
+#define lwip_mem_init()
+/* in case C library malloc() needs extra protection,
+ * allow these defines to be overridden.
+ */
+#ifndef mem_free
+#define mem_free free
+#endif
+#ifndef mem_malloc
+#define mem_malloc malloc
+#endif
+#ifndef mem_calloc
+#define mem_calloc calloc
+#endif
+/* Since there is no C library allocation function to shrink memory without
+   moving it, define this to nothing. */
+#ifndef mem_trim
+#define mem_trim(mem, size) (mem)
+#endif
+#else /* MEM_LIBC_MALLOC */
+
+/* MEM_SIZE would have to be aligned, but using 64000 here instead of
+ * 65535 leaves some room for alignment...
+ */
+#if MEM_SIZE > 64000L
+typedef u32_t mem_size_t;
+#define MEM_SIZE_F U32_F
+#else
+typedef u16_t mem_size_t;
+#define MEM_SIZE_F U16_F
+#endif /* MEM_SIZE > 64000 */
+
+#if MEM_USE_POOLS
+/** lwip_mem_init is not used when using pools instead of a heap */
+#define lwip_mem_init()
+/** mem_trim is not used when using pools instead of a heap:
+    we can't free part of a pool element and don't want to copy the rest */
+#define mem_trim(mem, size) (mem)
+#else /* MEM_USE_POOLS */
+/* lwIP alternative malloc */
+void  lwip_mem_init(void);
+void *mem_trim(void *mem, mem_size_t size);
+#endif /* MEM_USE_POOLS */
+void *mem_malloc(mem_size_t size);
+void *mem_calloc(mem_size_t count, mem_size_t size);
+void  mem_free(void *mem);
+#endif /* MEM_LIBC_MALLOC */
+
+/** Calculate memory size for an aligned buffer - returns the next highest
+ * multiple of MEM_ALIGNMENT (e.g. LWIP_MEM_ALIGN_SIZE(3) and
+ * LWIP_MEM_ALIGN_SIZE(4) will both yield 4 for MEM_ALIGNMENT == 4).
+ */
+#ifndef LWIP_MEM_ALIGN_SIZE
+#define LWIP_MEM_ALIGN_SIZE(size) (((size) + MEM_ALIGNMENT - 1) & ~(MEM_ALIGNMENT-1))
+#endif
+
+/** Calculate safe memory size for an aligned buffer when using an unaligned
+ * type as storage. This includes a safety-margin on (MEM_ALIGNMENT - 1) at the
+ * start (e.g. if buffer is u8_t[] and actual data will be u32_t*)
+ */
+#ifndef LWIP_MEM_ALIGN_BUFFER
+#define LWIP_MEM_ALIGN_BUFFER(size) (((size) + MEM_ALIGNMENT - 1))
+#endif
+
+/** Align a memory pointer to the alignment defined by MEM_ALIGNMENT
+ * so that ADDR % MEM_ALIGNMENT == 0
+ */
+#ifndef LWIP_MEM_ALIGN
+#define LWIP_MEM_ALIGN(addr) ((void *)(((mem_ptr_t)(addr) + MEM_ALIGNMENT - 1) & ~(mem_ptr_t)(MEM_ALIGNMENT-1)))
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_MEM_H__ */
diff --git a/core/lwip/src/include/lwip/memp.h b/core/lwip/src/include/lwip/memp.h
new file mode 100644
index 00000000..f0d07399
--- /dev/null
+++ b/core/lwip/src/include/lwip/memp.h
@@ -0,0 +1,116 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#ifndef __LWIP_MEMP_H__
+#define __LWIP_MEMP_H__
+
+#include "lwip/opt.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Create the list of all memory pools managed by memp. MEMP_MAX represents a NULL pool at the end */
+typedef enum {
+#define LWIP_MEMPOOL(name,num,size,desc)  MEMP_##name,
+#include "lwip/memp_std.h"
+  MEMP_MAX
+} memp_t;
+
+#if MEM_USE_POOLS
+/* Use a helper type to get the start and end of the user "memory pools" for mem_malloc */
+typedef enum {
+    /* Get the first (via:
+       MEMP_POOL_HELPER_START = ((u8_t) 1*MEMP_POOL_A + 0*MEMP_POOL_B + 0*MEMP_POOL_C + 0)*/
+    MEMP_POOL_HELPER_FIRST = ((u8_t)
+#define LWIP_MEMPOOL(name,num,size,desc)
+#define LWIP_MALLOC_MEMPOOL_START 1
+#define LWIP_MALLOC_MEMPOOL(num, size) * MEMP_POOL_##size + 0
+#define LWIP_MALLOC_MEMPOOL_END
+#include "lwip/memp_std.h"
+    ) ,
+    /* Get the last (via:
+       MEMP_POOL_HELPER_END = ((u8_t) 0 + MEMP_POOL_A*0 + MEMP_POOL_B*0 + MEMP_POOL_C*1) */
+    MEMP_POOL_HELPER_LAST = ((u8_t)
+#define LWIP_MEMPOOL(name,num,size,desc)
+#define LWIP_MALLOC_MEMPOOL_START
+#define LWIP_MALLOC_MEMPOOL(num, size) 0 + MEMP_POOL_##size *
+#define LWIP_MALLOC_MEMPOOL_END 1
+#include "lwip/memp_std.h"
+    )
+} memp_pool_helper_t;
+
+/* The actual start and stop values are here (cast them over)
+   We use this helper type and these defines so we can avoid using const memp_t values */
+#define MEMP_POOL_FIRST ((memp_t) MEMP_POOL_HELPER_FIRST)
+#define MEMP_POOL_LAST   ((memp_t) MEMP_POOL_HELPER_LAST)
+#endif /* MEM_USE_POOLS */
+
+#if MEMP_MEM_MALLOC || MEM_USE_POOLS
+extern const u16_t memp_sizes[MEMP_MAX];
+#endif /* MEMP_MEM_MALLOC || MEM_USE_POOLS */
+
+#if MEMP_MEM_MALLOC
+
+#include "mem.h"
+
+#define memp_init()
+#define memp_malloc(type)     mem_malloc(memp_sizes[type])
+#define memp_free(type, mem)  mem_free(mem)
+
+#else /* MEMP_MEM_MALLOC */
+
+#if MEM_USE_POOLS
+/** This structure is used to save the pool one element came from. */
+struct memp_malloc_helper
+{
+   memp_t poolnr;
+};
+#endif /* MEM_USE_POOLS */
+
+void  memp_init(void);
+
+#if MEMP_OVERFLOW_CHECK
+void *memp_malloc_fn(memp_t type, const char* file, const int line);
+#define memp_malloc(t) memp_malloc_fn((t), __FILE__, __LINE__)
+#else
+void *memp_malloc(memp_t type);
+#endif
+void  memp_free(memp_t type, void *mem);
+
+#endif /* MEMP_MEM_MALLOC */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_MEMP_H__ */
diff --git a/core/lwip/src/include/lwip/memp_std.h b/core/lwip/src/include/lwip/memp_std.h
new file mode 100644
index 00000000..6ce408fb
--- /dev/null
+++ b/core/lwip/src/include/lwip/memp_std.h
@@ -0,0 +1,122 @@
+/*
+ * SETUP: Make sure we define everything we will need.
+ *
+ * We have create three types of pools:
+ *   1) MEMPOOL - standard pools
+ *   2) MALLOC_MEMPOOL - to be used by mem_malloc in mem.c
+ *   3) PBUF_MEMPOOL - a mempool of pbuf's, so include space for the pbuf struct
+ *
+ * If the include'r doesn't require any special treatment of each of the types
+ * above, then will declare #2 & #3 to be just standard mempools.
+ */
+#ifndef LWIP_MALLOC_MEMPOOL
+/* This treats "malloc pools" just like any other pool.
+   The pools are a little bigger to provide 'size' as the amount of user data. */
+#define LWIP_MALLOC_MEMPOOL(num, size) LWIP_MEMPOOL(POOL_##size, num, (size + sizeof(struct memp_malloc_helper)), "MALLOC_"#size)
+#define LWIP_MALLOC_MEMPOOL_START
+#define LWIP_MALLOC_MEMPOOL_END
+#endif /* LWIP_MALLOC_MEMPOOL */ 
+
+#ifndef LWIP_PBUF_MEMPOOL
+/* This treats "pbuf pools" just like any other pool.
+ * Allocates buffers for a pbuf struct AND a payload size */
+#define LWIP_PBUF_MEMPOOL(name, num, payload, desc) LWIP_MEMPOOL(name, num, (MEMP_ALIGN_SIZE(sizeof(struct pbuf)) + MEMP_ALIGN_SIZE(payload)), desc)
+#endif /* LWIP_PBUF_MEMPOOL */
+
+
+/*
+ * A list of internal pools used by LWIP.
+ *
+ * LWIP_MEMPOOL(pool_name, number_elements, element_size, pool_description)
+ *     creates a pool name MEMP_pool_name. description is used in stats.c
+ */
+#if LWIP_RAW
+LWIP_MEMPOOL(RAW_PCB,        MEMP_NUM_RAW_PCB,         sizeof(struct raw_pcb),        "RAW_PCB")
+#endif /* LWIP_RAW */
+
+#if LWIP_UDP
+LWIP_MEMPOOL(UDP_PCB,        MEMP_NUM_UDP_PCB,         sizeof(struct udp_pcb),        "UDP_PCB")
+#endif /* LWIP_UDP */
+
+#if LWIP_TCP
+LWIP_MEMPOOL(TCP_PCB,        MEMP_NUM_TCP_PCB,         sizeof(struct tcp_pcb),        "TCP_PCB")
+LWIP_MEMPOOL(TCP_PCB_LISTEN, MEMP_NUM_TCP_PCB_LISTEN,  sizeof(struct tcp_pcb_listen), "TCP_PCB_LISTEN")
+LWIP_MEMPOOL(TCP_SEG,        MEMP_NUM_TCP_SEG,         sizeof(struct tcp_seg),        "TCP_SEG")
+#endif /* LWIP_TCP */
+
+#if IP_REASSEMBLY
+LWIP_MEMPOOL(REASSDATA,      MEMP_NUM_REASSDATA,       sizeof(struct ip_reassdata),   "REASSDATA")
+#endif /* IP_REASSEMBLY */
+#if IP_FRAG && !IP_FRAG_USES_STATIC_BUF && !LWIP_NETIF_TX_SINGLE_PBUF
+LWIP_MEMPOOL(FRAG_PBUF,      MEMP_NUM_FRAG_PBUF,       sizeof(struct pbuf_custom_ref),"FRAG_PBUF")
+#endif /* IP_FRAG && !IP_FRAG_USES_STATIC_BUF && !LWIP_NETIF_TX_SINGLE_PBUF */
+
+#if LWIP_NETCONN
+LWIP_MEMPOOL(NETBUF,         MEMP_NUM_NETBUF,          sizeof(struct netbuf),         "NETBUF")
+LWIP_MEMPOOL(NETCONN,        MEMP_NUM_NETCONN,         sizeof(struct netconn),        "NETCONN")
+#endif /* LWIP_NETCONN */
+
+#if NO_SYS==0
+LWIP_MEMPOOL(TCPIP_MSG_API,  MEMP_NUM_TCPIP_MSG_API,   sizeof(struct tcpip_msg),      "TCPIP_MSG_API")
+#if !LWIP_TCPIP_CORE_LOCKING_INPUT
+LWIP_MEMPOOL(TCPIP_MSG_INPKT,MEMP_NUM_TCPIP_MSG_INPKT, sizeof(struct tcpip_msg),      "TCPIP_MSG_INPKT")
+#endif /* !LWIP_TCPIP_CORE_LOCKING_INPUT */
+#endif /* NO_SYS==0 */
+
+#if ARP_QUEUEING
+LWIP_MEMPOOL(ARP_QUEUE,      MEMP_NUM_ARP_QUEUE,       sizeof(struct etharp_q_entry), "ARP_QUEUE")
+#endif /* ARP_QUEUEING */
+
+#if LWIP_IGMP
+LWIP_MEMPOOL(IGMP_GROUP,     MEMP_NUM_IGMP_GROUP,      sizeof(struct igmp_group),     "IGMP_GROUP")
+#endif /* LWIP_IGMP */
+
+#if (!NO_SYS || (NO_SYS && !NO_SYS_NO_TIMERS)) /* LWIP_TIMERS */
+LWIP_MEMPOOL(SYS_TIMEOUT,    MEMP_NUM_SYS_TIMEOUT,     sizeof(struct sys_timeo),      "SYS_TIMEOUT")
+#endif /* LWIP_TIMERS */
+
+#if LWIP_SNMP
+LWIP_MEMPOOL(SNMP_ROOTNODE,  MEMP_NUM_SNMP_ROOTNODE,   sizeof(struct mib_list_rootnode), "SNMP_ROOTNODE")
+LWIP_MEMPOOL(SNMP_NODE,      MEMP_NUM_SNMP_NODE,       sizeof(struct mib_list_node),     "SNMP_NODE")
+LWIP_MEMPOOL(SNMP_VARBIND,   MEMP_NUM_SNMP_VARBIND,    sizeof(struct snmp_varbind),      "SNMP_VARBIND")
+LWIP_MEMPOOL(SNMP_VALUE,     MEMP_NUM_SNMP_VALUE,      SNMP_MAX_VALUE_SIZE,              "SNMP_VALUE")
+#endif /* LWIP_SNMP */
+#if LWIP_DNS && LWIP_SOCKET
+LWIP_MEMPOOL(NETDB,          MEMP_NUM_NETDB,           NETDB_ELEM_SIZE,               "NETDB")
+#endif /* LWIP_DNS && LWIP_SOCKET */
+#if LWIP_DNS && DNS_LOCAL_HOSTLIST && DNS_LOCAL_HOSTLIST_IS_DYNAMIC
+LWIP_MEMPOOL(LOCALHOSTLIST,  MEMP_NUM_LOCALHOSTLIST,   LOCALHOSTLIST_ELEM_SIZE,       "LOCALHOSTLIST")
+#endif /* LWIP_DNS && DNS_LOCAL_HOSTLIST && DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
+#if PPP_SUPPORT && PPPOE_SUPPORT
+LWIP_MEMPOOL(PPPOE_IF,      MEMP_NUM_PPPOE_INTERFACES, sizeof(struct pppoe_softc),    "PPPOE_IF")
+#endif /* PPP_SUPPORT && PPPOE_SUPPORT */
+
+/*
+ * A list of pools of pbuf's used by LWIP.
+ *
+ * LWIP_PBUF_MEMPOOL(pool_name, number_elements, pbuf_payload_size, pool_description)
+ *     creates a pool name MEMP_pool_name. description is used in stats.c
+ *     This allocates enough space for the pbuf struct and a payload.
+ *     (Example: pbuf_payload_size=0 allocates only size for the struct)
+ */
+LWIP_PBUF_MEMPOOL(PBUF,      MEMP_NUM_PBUF,            0,                             "PBUF_REF/ROM")
+LWIP_PBUF_MEMPOOL(PBUF_POOL, PBUF_POOL_SIZE,           PBUF_POOL_BUFSIZE,             "PBUF_POOL")
+
+
+/*
+ * Allow for user-defined pools; this must be explicitly set in lwipopts.h
+ * since the default is to NOT look for lwippools.h
+ */
+#if MEMP_USE_CUSTOM_POOLS
+#include "lwippools.h"
+#endif /* MEMP_USE_CUSTOM_POOLS */
+
+/*
+ * REQUIRED CLEANUP: Clear up so we don't get "multiply defined" error later
+ * (#undef is ignored for something that is not defined)
+ */
+#undef LWIP_MEMPOOL
+#undef LWIP_MALLOC_MEMPOOL
+#undef LWIP_MALLOC_MEMPOOL_START
+#undef LWIP_MALLOC_MEMPOOL_END
+#undef LWIP_PBUF_MEMPOOL
diff --git a/core/lwip/src/include/lwip/netbuf.h b/core/lwip/src/include/lwip/netbuf.h
new file mode 100644
index 00000000..7d247d71
--- /dev/null
+++ b/core/lwip/src/include/lwip/netbuf.h
@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_NETBUF_H__
+#define __LWIP_NETBUF_H__
+
+#include "lwip/opt.h"
+#include "lwip/pbuf.h"
+#include "lwip/ip_addr.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** This netbuf has dest-addr/port set */
+#define NETBUF_FLAG_DESTADDR    0x01
+/** This netbuf includes a checksum */
+#define NETBUF_FLAG_CHKSUM      0x02
+
+struct netbuf {
+  struct pbuf *p, *ptr;
+  ip_addr_t addr;
+  u16_t port;
+#if LWIP_NETBUF_RECVINFO || LWIP_CHECKSUM_ON_COPY
+#if LWIP_CHECKSUM_ON_COPY
+  u8_t flags;
+#endif /* LWIP_CHECKSUM_ON_COPY */
+  u16_t toport_chksum;
+#if LWIP_NETBUF_RECVINFO
+  ip_addr_t toaddr;
+#endif /* LWIP_NETBUF_RECVINFO */
+#endif /* LWIP_NETBUF_RECVINFO || LWIP_CHECKSUM_ON_COPY */
+};
+
+/* Network buffer functions: */
+struct netbuf *   netbuf_new      (void);
+void              netbuf_delete   (struct netbuf *buf);
+void *            netbuf_alloc    (struct netbuf *buf, u16_t size);
+void              netbuf_free     (struct netbuf *buf);
+err_t             netbuf_ref      (struct netbuf *buf,
+                                   const void *dataptr, u16_t size);
+void              netbuf_chain    (struct netbuf *head,
+           struct netbuf *tail);
+
+err_t             netbuf_data     (struct netbuf *buf,
+                                   void **dataptr, u16_t *len);
+s8_t              netbuf_next     (struct netbuf *buf);
+void              netbuf_first    (struct netbuf *buf);
+
+
+#define netbuf_copy_partial(buf, dataptr, len, offset) \
+  pbuf_copy_partial((buf)->p, (dataptr), (len), (offset))
+#define netbuf_copy(buf,dataptr,len) netbuf_copy_partial(buf, dataptr, len, 0)
+#define netbuf_take(buf, dataptr, len) pbuf_take((buf)->p, dataptr, len)
+#define netbuf_len(buf)              ((buf)->p->tot_len)
+#define netbuf_fromaddr(buf)         (&((buf)->addr))
+#define netbuf_set_fromaddr(buf, fromaddr) ip_addr_set((&(buf)->addr), fromaddr)
+#define netbuf_fromport(buf)         ((buf)->port)
+#if LWIP_NETBUF_RECVINFO
+#define netbuf_destaddr(buf)         (&((buf)->toaddr))
+#define netbuf_set_destaddr(buf, destaddr) ip_addr_set((&(buf)->addr), destaddr)
+#define netbuf_destport(buf)         (((buf)->flags & NETBUF_FLAG_DESTADDR) ? (buf)->toport_chksum : 0)
+#endif /* LWIP_NETBUF_RECVINFO */
+#if LWIP_CHECKSUM_ON_COPY
+#define netbuf_set_chksum(buf, chksum) do { (buf)->flags = NETBUF_FLAG_CHKSUM; \
+                                            (buf)->toport_chksum = chksum; } while(0)
+#endif /* LWIP_CHECKSUM_ON_COPY */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_NETBUF_H__ */
diff --git a/core/lwip/src/include/lwip/netdb.h b/core/lwip/src/include/lwip/netdb.h
new file mode 100644
index 00000000..7587e2f2
--- /dev/null
+++ b/core/lwip/src/include/lwip/netdb.h
@@ -0,0 +1,124 @@
+/*
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Simon Goldschmidt
+ *
+ */
+#ifndef __LWIP_NETDB_H__
+#define __LWIP_NETDB_H__
+
+#include "lwip/opt.h"
+
+#if LWIP_DNS && LWIP_SOCKET
+
+#include <stddef.h> /* for size_t */
+
+#include "lwip/inet.h"
+#include "lwip/sockets.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* some rarely used options */
+#ifndef LWIP_DNS_API_DECLARE_H_ERRNO
+#define LWIP_DNS_API_DECLARE_H_ERRNO 1
+#endif
+
+#ifndef LWIP_DNS_API_DEFINE_ERRORS
+#define LWIP_DNS_API_DEFINE_ERRORS 1
+#endif
+
+#ifndef LWIP_DNS_API_DECLARE_STRUCTS
+#define LWIP_DNS_API_DECLARE_STRUCTS 1
+#endif
+
+#if LWIP_DNS_API_DEFINE_ERRORS
+/** Errors used by the DNS API functions, h_errno can be one of them */
+#define EAI_NONAME      200
+#define EAI_SERVICE     201
+#define EAI_FAIL        202
+#define EAI_MEMORY      203
+
+#define HOST_NOT_FOUND  210
+#define NO_DATA         211
+#define NO_RECOVERY     212
+#define TRY_AGAIN       213
+#endif /* LWIP_DNS_API_DEFINE_ERRORS */
+
+#if LWIP_DNS_API_DECLARE_STRUCTS
+struct hostent {
+    char  *h_name;      /* Official name of the host. */
+    char **h_aliases;   /* A pointer to an array of pointers to alternative host names,
+                           terminated by a null pointer. */
+    int    h_addrtype;  /* Address type. */
+    int    h_length;    /* The length, in bytes, of the address. */
+    char **h_addr_list; /* A pointer to an array of pointers to network addresses (in
+                           network byte order) for the host, terminated by a null pointer. */
+#define h_addr h_addr_list[0] /* for backward compatibility */
+};
+
+struct addrinfo {
+    int               ai_flags;      /* Input flags. */
+    int               ai_family;     /* Address family of socket. */
+    int               ai_socktype;   /* Socket type. */
+    int               ai_protocol;   /* Protocol of socket. */
+    socklen_t         ai_addrlen;    /* Length of socket address. */
+    struct sockaddr  *ai_addr;       /* Socket address of socket. */
+    char             *ai_canonname;  /* Canonical name of service location. */
+    struct addrinfo  *ai_next;       /* Pointer to next in list. */
+};
+#endif /* LWIP_DNS_API_DECLARE_STRUCTS */
+
+#if LWIP_DNS_API_DECLARE_H_ERRNO
+/* application accessable error code set by the DNS API functions */
+extern int h_errno;
+#endif /* LWIP_DNS_API_DECLARE_H_ERRNO*/
+
+struct hostent *lwip_gethostbyname(const char *name);
+int lwip_gethostbyname_r(const char *name, struct hostent *ret, char *buf,
+                size_t buflen, struct hostent **result, int *h_errnop);
+void lwip_freeaddrinfo(struct addrinfo *ai);
+int lwip_getaddrinfo(const char *nodename,
+       const char *servname,
+       const struct addrinfo *hints,
+       struct addrinfo **res);
+
+#if LWIP_COMPAT_SOCKETS
+#define gethostbyname(name) lwip_gethostbyname(name)
+#define gethostbyname_r(name, ret, buf, buflen, result, h_errnop) \
+       lwip_gethostbyname_r(name, ret, buf, buflen, result, h_errnop)
+#define freeaddrinfo(addrinfo) lwip_freeaddrinfo(addrinfo)
+#define getaddrinfo(nodname, servname, hints, res) \
+       lwip_getaddrinfo(nodname, servname, hints, res)
+#endif /* LWIP_COMPAT_SOCKETS */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_DNS && LWIP_SOCKET */
+
+#endif /* __LWIP_NETDB_H__ */
diff --git a/core/lwip/src/include/lwip/netif.h b/core/lwip/src/include/lwip/netif.h
new file mode 100644
index 00000000..8e799295
--- /dev/null
+++ b/core/lwip/src/include/lwip/netif.h
@@ -0,0 +1,315 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_NETIF_H__
+#define __LWIP_NETIF_H__
+
+#include "lwip/opt.h"
+
+#define ENABLE_LOOPBACK (LWIP_NETIF_LOOPBACK || LWIP_HAVE_LOOPIF)
+
+#include "lwip/err.h"
+
+#include "lwip/ip_addr.h"
+
+#include "lwip/def.h"
+#include "lwip/pbuf.h"
+#if LWIP_DHCP
+struct dhcp;
+#endif
+#if LWIP_AUTOIP
+struct autoip;
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Throughout this file, IP addresses are expected to be in
+ * the same byte order as in IP_PCB. */
+
+/** must be the maximum of all used hardware address lengths
+    across all types of interfaces in use */
+#define NETIF_MAX_HWADDR_LEN 32U
+
+/** Whether the network interface is 'up'. This is
+ * a software flag used to control whether this network
+ * interface is enabled and processes traffic.
+ * It is set by the startup code (for static IP configuration) or
+ * by dhcp/autoip when an address has been assigned.
+ */
+#define NETIF_FLAG_UP           0x01U
+/** If set, the netif has broadcast capability.
+ * Set by the netif driver in its init function. */
+#define NETIF_FLAG_BROADCAST    0x02U
+/** If set, the netif is one end of a point-to-point connection.
+ * Set by the netif driver in its init function. */
+#define NETIF_FLAG_POINTTOPOINT 0x04U
+/** If set, the interface is configured using DHCP.
+ * Set by the DHCP code when starting or stopping DHCP. */
+#define NETIF_FLAG_DHCP         0x08U
+/** If set, the interface has an active link
+ *  (set by the network interface driver).
+ * Either set by the netif driver in its init function (if the link
+ * is up at that time) or at a later point once the link comes up
+ * (if link detection is supported by the hardware). */
+#define NETIF_FLAG_LINK_UP      0x10U
+/** If set, the netif is an ethernet device using ARP.
+ * Set by the netif driver in its init function.
+ * Used to check input packet types and use of DHCP. */
+#define NETIF_FLAG_ETHARP       0x20U
+/** If set, the netif is an ethernet device. It might not use
+ * ARP or TCP/IP if it is used for PPPoE only.
+ */
+#define NETIF_FLAG_ETHERNET     0x40U
+/** If set, the netif has IGMP capability.
+ * Set by the netif driver in its init function. */
+#define NETIF_FLAG_IGMP         0x80U
+
+/** Function prototype for netif init functions. Set up flags and output/linkoutput
+ * callback functions in this function.
+ *
+ * @param netif The netif to initialize
+ */
+typedef err_t (*netif_init_fn)(struct netif *netif);
+/** Function prototype for netif->input functions. This function is saved as 'input'
+ * callback function in the netif struct. Call it when a packet has been received.
+ *
+ * @param p The received packet, copied into a pbuf
+ * @param inp The netif which received the packet
+ */
+typedef err_t (*netif_input_fn)(struct pbuf *p, struct netif *inp);
+/** Function prototype for netif->output functions. Called by lwIP when a packet
+ * shall be sent. For ethernet netif, set this to 'etharp_output' and set
+ * 'linkoutput'.
+ *
+ * @param netif The netif which shall send a packet
+ * @param p The packet to send (p->payload points to IP header)
+ * @param ipaddr The IP address to which the packet shall be sent
+ */
+typedef err_t (*netif_output_fn)(struct netif *netif, struct pbuf *p,
+       ip_addr_t *ipaddr);
+/** Function prototype for netif->linkoutput functions. Only used for ethernet
+ * netifs. This function is called by ARP when a packet shall be sent.
+ *
+ * @param netif The netif which shall send a packet
+ * @param p The packet to send (raw ethernet packet)
+ */
+typedef err_t (*netif_linkoutput_fn)(struct netif *netif, struct pbuf *p);
+/** Function prototype for netif status- or link-callback functions. */
+typedef void (*netif_status_callback_fn)(struct netif *netif);
+/** Function prototype for netif igmp_mac_filter functions */
+typedef err_t (*netif_igmp_mac_filter_fn)(struct netif *netif,
+       ip_addr_t *group, u8_t action);
+
+/** Generic data structure used for all lwIP network interfaces.
+ *  The following fields should be filled in by the initialization
+ *  function for the device driver: hwaddr_len, hwaddr[], mtu, flags */
+struct netif {
+  /** pointer to next in linked list */
+  struct netif *next;
+
+  /** IP address configuration in network byte order */
+  ip_addr_t ip_addr;
+  ip_addr_t netmask;
+  ip_addr_t gw;
+
+  /** This function is called by the network device driver
+   *  to pass a packet up the TCP/IP stack. */
+  netif_input_fn input;
+  /** This function is called by the IP module when it wants
+   *  to send a packet on the interface. This function typically
+   *  first resolves the hardware address, then sends the packet. */
+  netif_output_fn output;
+  /** This function is called by the ARP module when it wants
+   *  to send a packet on the interface. This function outputs
+   *  the pbuf as-is on the link medium. */
+  netif_linkoutput_fn linkoutput;
+#if LWIP_NETIF_STATUS_CALLBACK
+  /** This function is called when the netif state is set to up or down
+   */
+  netif_status_callback_fn status_callback;
+#endif /* LWIP_NETIF_STATUS_CALLBACK */
+#if LWIP_NETIF_LINK_CALLBACK
+  /** This function is called when the netif link is set to up or down
+   */
+  netif_status_callback_fn link_callback;
+#endif /* LWIP_NETIF_LINK_CALLBACK */
+  /** This field can be set by the device driver and could point
+   *  to state information for the device. */
+  void *state;
+#if LWIP_DHCP
+  /** the DHCP client state information for this netif */
+  struct dhcp *dhcp;
+#endif /* LWIP_DHCP */
+#if LWIP_AUTOIP
+  /** the AutoIP client state information for this netif */
+  struct autoip *autoip;
+#endif
+#if LWIP_NETIF_HOSTNAME
+  /* the hostname for this netif, NULL is a valid value */
+  char*  hostname;
+#endif /* LWIP_NETIF_HOSTNAME */
+  /** maximum transfer unit (in bytes) */
+  u16_t mtu;
+  /** number of bytes used in hwaddr */
+  u8_t hwaddr_len;
+  /** link level hardware address of this interface */
+  u8_t hwaddr[NETIF_MAX_HWADDR_LEN];
+  /** flags (see NETIF_FLAG_ above) */
+  u8_t flags;
+  /** descriptive abbreviation */
+  char name[2];
+  /** number of this interface */
+  u8_t num;
+#if LWIP_SNMP
+  /** link type (from "snmp_ifType" enum from snmp.h) */
+  u8_t link_type;
+  /** (estimate) link speed */
+  u32_t link_speed;
+  /** timestamp at last change made (up/down) */
+  u32_t ts;
+  /** counters */
+  u32_t ifinoctets;
+  u32_t ifinucastpkts;
+  u32_t ifinnucastpkts;
+  u32_t ifindiscards;
+  u32_t ifoutoctets;
+  u32_t ifoutucastpkts;
+  u32_t ifoutnucastpkts;
+  u32_t ifoutdiscards;
+#endif /* LWIP_SNMP */
+#if LWIP_IGMP
+  /** This function could be called to add or delete a entry in the multicast
+      filter table of the ethernet MAC.*/
+  netif_igmp_mac_filter_fn igmp_mac_filter;
+#endif /* LWIP_IGMP */
+#if LWIP_NETIF_HWADDRHINT
+  u8_t *addr_hint;
+#endif /* LWIP_NETIF_HWADDRHINT */
+#if ENABLE_LOOPBACK
+  /* List of packets to be queued for ourselves. */
+  struct pbuf *loop_first;
+  struct pbuf *loop_last;
+#if LWIP_LOOPBACK_MAX_PBUFS
+  u16_t loop_cnt_current;
+#endif /* LWIP_LOOPBACK_MAX_PBUFS */
+#endif /* ENABLE_LOOPBACK */
+};
+
+#if LWIP_SNMP
+#define NETIF_INIT_SNMP(netif, type, speed) \
+  /* use "snmp_ifType" enum from snmp.h for "type", snmp_ifType_ethernet_csmacd by example */ \
+  (netif)->link_type = (type);    \
+  /* your link speed here (units: bits per second) */  \
+  (netif)->link_speed = (speed);  \
+  (netif)->ts = 0;              \
+  (netif)->ifinoctets = 0;      \
+  (netif)->ifinucastpkts = 0;   \
+  (netif)->ifinnucastpkts = 0;  \
+  (netif)->ifindiscards = 0;    \
+  (netif)->ifoutoctets = 0;     \
+  (netif)->ifoutucastpkts = 0;  \
+  (netif)->ifoutnucastpkts = 0; \
+  (netif)->ifoutdiscards = 0
+#else /* LWIP_SNMP */
+#define NETIF_INIT_SNMP(netif, type, speed)
+#endif /* LWIP_SNMP */
+
+
+/** The list of network interfaces. */
+extern struct netif *netif_list;
+/** The default network interface. */
+extern struct netif *netif_default;
+
+void netif_init(void);
+
+struct netif *netif_add(struct netif *netif, ip_addr_t *ipaddr, ip_addr_t *netmask,
+      ip_addr_t *gw, void *state, netif_init_fn init, netif_input_fn input);
+
+void
+netif_set_addr(struct netif *netif, ip_addr_t *ipaddr, ip_addr_t *netmask,
+      ip_addr_t *gw);
+void netif_remove(struct netif * netif);
+
+/* Returns a network interface given its name. The name is of the form
+   "et0", where the first two letters are the "name" field in the
+   netif structure, and the digit is in the num field in the same
+   structure. */
+struct netif *netif_find(char *name);
+
+void netif_set_default(struct netif *netif);
+
+void netif_set_ipaddr(struct netif *netif, ip_addr_t *ipaddr);
+void netif_set_netmask(struct netif *netif, ip_addr_t *netmask);
+void netif_set_gw(struct netif *netif, ip_addr_t *gw);
+
+void netif_set_up(struct netif *netif);
+void netif_set_down(struct netif *netif);
+/** Ask if an interface is up */
+#define netif_is_up(netif) (((netif)->flags & NETIF_FLAG_UP) ? (u8_t)1 : (u8_t)0)
+
+#if LWIP_NETIF_STATUS_CALLBACK
+void netif_set_status_callback(struct netif *netif, netif_status_callback_fn status_callback);
+#endif /* LWIP_NETIF_STATUS_CALLBACK */
+
+void netif_set_link_up(struct netif *netif);
+void netif_set_link_down(struct netif *netif);
+/** Ask if a link is up */ 
+#define netif_is_link_up(netif) (((netif)->flags & NETIF_FLAG_LINK_UP) ? (u8_t)1 : (u8_t)0)
+
+#if LWIP_NETIF_LINK_CALLBACK
+void netif_set_link_callback(struct netif *netif, netif_status_callback_fn link_callback);
+#endif /* LWIP_NETIF_LINK_CALLBACK */
+
+#if LWIP_NETIF_HOSTNAME
+#define netif_set_hostname(netif, name) do { if((netif) != NULL) { (netif)->hostname = name; }}while(0)
+#define netif_get_hostname(netif) (((netif) != NULL) ? ((netif)->hostname) : NULL)
+#endif /* LWIP_NETIF_HOSTNAME */
+
+#if LWIP_IGMP
+#define netif_set_igmp_mac_filter(netif, function) do { if((netif) != NULL) { (netif)->igmp_mac_filter = function; }}while(0)
+#define netif_get_igmp_mac_filter(netif) (((netif) != NULL) ? ((netif)->igmp_mac_filter) : NULL)
+#endif /* LWIP_IGMP */
+
+#if ENABLE_LOOPBACK
+err_t netif_loop_output(struct netif *netif, struct pbuf *p, ip_addr_t *dest_ip);
+void netif_poll(struct netif *netif);
+#if !LWIP_NETIF_LOOPBACK_MULTITHREADING
+void netif_poll_all(void);
+#endif /* !LWIP_NETIF_LOOPBACK_MULTITHREADING */
+#endif /* ENABLE_LOOPBACK */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_NETIF_H__ */
diff --git a/core/lwip/src/include/lwip/netifapi.h b/core/lwip/src/include/lwip/netifapi.h
new file mode 100644
index 00000000..33318efa
--- /dev/null
+++ b/core/lwip/src/include/lwip/netifapi.h
@@ -0,0 +1,108 @@
+/*
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ */
+ 
+#ifndef __LWIP_NETIFAPI_H__
+#define __LWIP_NETIFAPI_H__
+
+#include "lwip/opt.h"
+
+#if LWIP_NETIF_API /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/sys.h"
+#include "lwip/netif.h"
+#include "lwip/dhcp.h"
+#include "lwip/autoip.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef void (*netifapi_void_fn)(struct netif *netif);
+typedef err_t (*netifapi_errt_fn)(struct netif *netif);
+
+struct netifapi_msg_msg {
+#if !LWIP_TCPIP_CORE_LOCKING
+  sys_sem_t sem;
+#endif /* !LWIP_TCPIP_CORE_LOCKING */
+  err_t err;
+  struct netif *netif;
+  union {
+    struct {
+      ip_addr_t *ipaddr;
+      ip_addr_t *netmask;
+      ip_addr_t *gw;
+      void *state;
+      netif_init_fn init;
+      netif_input_fn input;
+    } add;
+    struct {
+      netifapi_void_fn voidfunc;
+      netifapi_errt_fn errtfunc;
+    } common;
+  } msg;
+};
+
+struct netifapi_msg {
+  void (* function)(struct netifapi_msg_msg *msg);
+  struct netifapi_msg_msg msg;
+};
+
+
+/* API for application */
+err_t netifapi_netif_add       ( struct netif *netif,
+                                 ip_addr_t *ipaddr,
+                                 ip_addr_t *netmask,
+                                 ip_addr_t *gw,
+                                 void *state,
+                                 netif_init_fn init,
+                                 netif_input_fn input);
+
+err_t netifapi_netif_set_addr  ( struct netif *netif,
+                                 ip_addr_t *ipaddr,
+                                 ip_addr_t *netmask,
+                                 ip_addr_t *gw );
+
+err_t netifapi_netif_common    ( struct netif *netif,
+                                 netifapi_void_fn voidfunc,
+                                 netifapi_errt_fn errtfunc);
+
+#define netifapi_netif_remove(n)      netifapi_netif_common(n, netif_remove, NULL)
+#define netifapi_netif_set_up(n)      netifapi_netif_common(n, netif_set_up, NULL)
+#define netifapi_netif_set_down(n)    netifapi_netif_common(n, netif_set_down, NULL)
+#define netifapi_netif_set_default(n) netifapi_netif_common(n, netif_set_default, NULL)
+#define netifapi_dhcp_start(n)        netifapi_netif_common(n, NULL, dhcp_start)
+#define netifapi_dhcp_stop(n)         netifapi_netif_common(n, dhcp_stop, NULL)
+#define netifapi_autoip_start(n)      netifapi_netif_common(n, NULL, autoip_start)
+#define netifapi_autoip_stop(n)       netifapi_netif_common(n, NULL, autoip_stop)
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_NETIF_API */
+
+#endif /* __LWIP_NETIFAPI_H__ */
diff --git a/core/lwip/src/include/lwip/opt.h b/core/lwip/src/include/lwip/opt.h
new file mode 100644
index 00000000..a1b87658
--- /dev/null
+++ b/core/lwip/src/include/lwip/opt.h
@@ -0,0 +1,2043 @@
+/**
+ * @file
+ *
+ * lwIP Options Configuration
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_OPT_H__
+#define __LWIP_OPT_H__
+
+/*
+ * Include user defined options first. Anything not defined in these files
+ * will be set to standard values. Override anything you dont like!
+ */
+#include "lwipopts.h"
+#include "lwip/debug.h"
+
+/*
+   -----------------------------------------------
+   ---------- Platform specific locking ----------
+   -----------------------------------------------
+*/
+
+/**
+ * SYS_LIGHTWEIGHT_PROT==1: if you want inter-task protection for certain
+ * critical regions during buffer allocation, deallocation and memory
+ * allocation and deallocation.
+ */
+#ifndef SYS_LIGHTWEIGHT_PROT
+#define SYS_LIGHTWEIGHT_PROT            0
+#endif
+
+/** 
+ * NO_SYS==1: Provides VERY minimal functionality. Otherwise,
+ * use lwIP facilities.
+ */
+#ifndef NO_SYS
+#define NO_SYS                          0
+#endif
+
+/**
+ * NO_SYS_NO_TIMERS==1: Drop support for sys_timeout when NO_SYS==1
+ * Mainly for compatibility to old versions.
+ */
+#ifndef NO_SYS_NO_TIMERS
+#define NO_SYS_NO_TIMERS                0
+#endif
+
+/**
+ * MEMCPY: override this if you have a faster implementation at hand than the
+ * one included in your C library
+ */
+#ifndef MEMCPY
+#define MEMCPY(dst,src,len)             memcpy(dst,src,len)
+#endif
+
+/**
+ * SMEMCPY: override this with care! Some compilers (e.g. gcc) can inline a
+ * call to memcpy() if the length is known at compile time and is small.
+ */
+#ifndef SMEMCPY
+#define SMEMCPY(dst,src,len)            memcpy(dst,src,len)
+#endif
+
+/*
+   ------------------------------------
+   ---------- Memory options ----------
+   ------------------------------------
+*/
+/**
+ * MEM_LIBC_MALLOC==1: Use malloc/free/realloc provided by your C-library
+ * instead of the lwip internal allocator. Can save code size if you
+ * already use it.
+ */
+#ifndef MEM_LIBC_MALLOC
+#define MEM_LIBC_MALLOC                 0
+#endif
+
+/**
+* MEMP_MEM_MALLOC==1: Use mem_malloc/mem_free instead of the lwip pool allocator.
+* Especially useful with MEM_LIBC_MALLOC but handle with care regarding execution
+* speed and usage from interrupts!
+*/
+#ifndef MEMP_MEM_MALLOC
+#define MEMP_MEM_MALLOC                 0
+#endif
+
+/**
+ * MEM_ALIGNMENT: should be set to the alignment of the CPU
+ *    4 byte alignment -> #define MEM_ALIGNMENT 4
+ *    2 byte alignment -> #define MEM_ALIGNMENT 2
+ */
+#ifndef MEM_ALIGNMENT
+#define MEM_ALIGNMENT                   1
+#endif
+
+/**
+ * MEM_SIZE: the size of the heap memory. If the application will send
+ * a lot of data that needs to be copied, this should be set high.
+ */
+#ifndef MEM_SIZE
+#define MEM_SIZE                        1600
+#endif
+
+/**
+ * MEMP_SEPARATE_POOLS: if defined to 1, each pool is placed in its own array.
+ * This can be used to individually change the location of each pool.
+ * Default is one big array for all pools
+ */
+#ifndef MEMP_SEPARATE_POOLS
+#define MEMP_SEPARATE_POOLS             0
+#endif
+
+/**
+ * MEMP_OVERFLOW_CHECK: memp overflow protection reserves a configurable
+ * amount of bytes before and after each memp element in every pool and fills
+ * it with a prominent default value.
+ *    MEMP_OVERFLOW_CHECK == 0 no checking
+ *    MEMP_OVERFLOW_CHECK == 1 checks each element when it is freed
+ *    MEMP_OVERFLOW_CHECK >= 2 checks each element in every pool every time
+ *      memp_malloc() or memp_free() is called (useful but slow!)
+ */
+#ifndef MEMP_OVERFLOW_CHECK
+#define MEMP_OVERFLOW_CHECK             0
+#endif
+
+/**
+ * MEMP_SANITY_CHECK==1: run a sanity check after each memp_free() to make
+ * sure that there are no cycles in the linked lists.
+ */
+#ifndef MEMP_SANITY_CHECK
+#define MEMP_SANITY_CHECK               0
+#endif
+
+/**
+ * MEM_USE_POOLS==1: Use an alternative to malloc() by allocating from a set
+ * of memory pools of various sizes. When mem_malloc is called, an element of
+ * the smallest pool that can provide the length needed is returned.
+ * To use this, MEMP_USE_CUSTOM_POOLS also has to be enabled.
+ */
+#ifndef MEM_USE_POOLS
+#define MEM_USE_POOLS                   0
+#endif
+
+/**
+ * MEM_USE_POOLS_TRY_BIGGER_POOL==1: if one malloc-pool is empty, try the next
+ * bigger pool - WARNING: THIS MIGHT WASTE MEMORY but it can make a system more
+ * reliable. */
+#ifndef MEM_USE_POOLS_TRY_BIGGER_POOL
+#define MEM_USE_POOLS_TRY_BIGGER_POOL   0
+#endif
+
+/**
+ * MEMP_USE_CUSTOM_POOLS==1: whether to include a user file lwippools.h
+ * that defines additional pools beyond the "standard" ones required
+ * by lwIP. If you set this to 1, you must have lwippools.h in your 
+ * inlude path somewhere. 
+ */
+#ifndef MEMP_USE_CUSTOM_POOLS
+#define MEMP_USE_CUSTOM_POOLS           0
+#endif
+
+/**
+ * Set this to 1 if you want to free PBUF_RAM pbufs (or call mem_free()) from
+ * interrupt context (or another context that doesn't allow waiting for a
+ * semaphore).
+ * If set to 1, mem_malloc will be protected by a semaphore and SYS_ARCH_PROTECT,
+ * while mem_free will only use SYS_ARCH_PROTECT. mem_malloc SYS_ARCH_UNPROTECTs
+ * with each loop so that mem_free can run.
+ *
+ * ATTENTION: As you can see from the above description, this leads to dis-/
+ * enabling interrupts often, which can be slow! Also, on low memory, mem_malloc
+ * can need longer.
+ *
+ * If you don't want that, at least for NO_SYS=0, you can still use the following
+ * functions to enqueue a deallocation call which then runs in the tcpip_thread
+ * context:
+ * - pbuf_free_callback(p);
+ * - mem_free_callback(m);
+ */
+#ifndef LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT
+#define LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT 0
+#endif
+
+/*
+   ------------------------------------------------
+   ---------- Internal Memory Pool Sizes ----------
+   ------------------------------------------------
+*/
+/**
+ * MEMP_NUM_PBUF: the number of memp struct pbufs (used for PBUF_ROM and PBUF_REF).
+ * If the application sends a lot of data out of ROM (or other static memory),
+ * this should be set high.
+ */
+#ifndef MEMP_NUM_PBUF
+#define MEMP_NUM_PBUF                   16
+#endif
+
+/**
+ * MEMP_NUM_RAW_PCB: Number of raw connection PCBs
+ * (requires the LWIP_RAW option)
+ */
+#ifndef MEMP_NUM_RAW_PCB
+#define MEMP_NUM_RAW_PCB                4
+#endif
+
+/**
+ * MEMP_NUM_UDP_PCB: the number of UDP protocol control blocks. One
+ * per active UDP "connection".
+ * (requires the LWIP_UDP option)
+ */
+#ifndef MEMP_NUM_UDP_PCB
+#define MEMP_NUM_UDP_PCB                4
+#endif
+
+/**
+ * MEMP_NUM_TCP_PCB: the number of simulatenously active TCP connections.
+ * (requires the LWIP_TCP option)
+ */
+#ifndef MEMP_NUM_TCP_PCB
+#define MEMP_NUM_TCP_PCB                5
+#endif
+
+/**
+ * MEMP_NUM_TCP_PCB_LISTEN: the number of listening TCP connections.
+ * (requires the LWIP_TCP option)
+ */
+#ifndef MEMP_NUM_TCP_PCB_LISTEN
+#define MEMP_NUM_TCP_PCB_LISTEN         8
+#endif
+
+/**
+ * MEMP_NUM_TCP_SEG: the number of simultaneously queued TCP segments.
+ * (requires the LWIP_TCP option)
+ */
+#ifndef MEMP_NUM_TCP_SEG
+#define MEMP_NUM_TCP_SEG                16
+#endif
+
+/**
+ * MEMP_NUM_REASSDATA: the number of IP packets simultaneously queued for
+ * reassembly (whole packets, not fragments!)
+ */
+#ifndef MEMP_NUM_REASSDATA
+#define MEMP_NUM_REASSDATA              5
+#endif
+
+/**
+ * MEMP_NUM_FRAG_PBUF: the number of IP fragments simultaneously sent
+ * (fragments, not whole packets!).
+ * This is only used with IP_FRAG_USES_STATIC_BUF==0 and
+ * LWIP_NETIF_TX_SINGLE_PBUF==0 and only has to be > 1 with DMA-enabled MACs
+ * where the packet is not yet sent when netif->output returns.
+ */
+#ifndef MEMP_NUM_FRAG_PBUF
+#define MEMP_NUM_FRAG_PBUF              15
+#endif
+
+/**
+ * MEMP_NUM_ARP_QUEUE: the number of simulateously queued outgoing
+ * packets (pbufs) that are waiting for an ARP request (to resolve
+ * their destination address) to finish.
+ * (requires the ARP_QUEUEING option)
+ */
+#ifndef MEMP_NUM_ARP_QUEUE
+#define MEMP_NUM_ARP_QUEUE              30
+#endif
+
+/**
+ * MEMP_NUM_IGMP_GROUP: The number of multicast groups whose network interfaces
+ * can be members et the same time (one per netif - allsystems group -, plus one
+ * per netif membership).
+ * (requires the LWIP_IGMP option)
+ */
+#ifndef MEMP_NUM_IGMP_GROUP
+#define MEMP_NUM_IGMP_GROUP             8
+#endif
+
+/**
+ * MEMP_NUM_SYS_TIMEOUT: the number of simulateously active timeouts.
+ * (requires NO_SYS==0)
+ */
+#ifndef MEMP_NUM_SYS_TIMEOUT
+#define MEMP_NUM_SYS_TIMEOUT            3
+#endif
+
+/**
+ * MEMP_NUM_NETBUF: the number of struct netbufs.
+ * (only needed if you use the sequential API, like api_lib.c)
+ */
+#ifndef MEMP_NUM_NETBUF
+#define MEMP_NUM_NETBUF                 2
+#endif
+
+/**
+ * MEMP_NUM_NETCONN: the number of struct netconns.
+ * (only needed if you use the sequential API, like api_lib.c)
+ */
+#ifndef MEMP_NUM_NETCONN
+#define MEMP_NUM_NETCONN                4
+#endif
+
+/**
+ * MEMP_NUM_TCPIP_MSG_API: the number of struct tcpip_msg, which are used
+ * for callback/timeout API communication. 
+ * (only needed if you use tcpip.c)
+ */
+#ifndef MEMP_NUM_TCPIP_MSG_API
+#define MEMP_NUM_TCPIP_MSG_API          8
+#endif
+
+/**
+ * MEMP_NUM_TCPIP_MSG_INPKT: the number of struct tcpip_msg, which are used
+ * for incoming packets. 
+ * (only needed if you use tcpip.c)
+ */
+#ifndef MEMP_NUM_TCPIP_MSG_INPKT
+#define MEMP_NUM_TCPIP_MSG_INPKT        8
+#endif
+
+/**
+ * MEMP_NUM_SNMP_NODE: the number of leafs in the SNMP tree.
+ */
+#ifndef MEMP_NUM_SNMP_NODE
+#define MEMP_NUM_SNMP_NODE              50
+#endif
+
+/**
+ * MEMP_NUM_SNMP_ROOTNODE: the number of branches in the SNMP tree.
+ * Every branch has one leaf (MEMP_NUM_SNMP_NODE) at least!
+ */
+#ifndef MEMP_NUM_SNMP_ROOTNODE
+#define MEMP_NUM_SNMP_ROOTNODE          30
+#endif
+
+/**
+ * MEMP_NUM_SNMP_VARBIND: the number of concurrent requests (does not have to
+ * be changed normally) - 2 of these are used per request (1 for input,
+ * 1 for output)
+ */
+#ifndef MEMP_NUM_SNMP_VARBIND
+#define MEMP_NUM_SNMP_VARBIND           2
+#endif
+
+/**
+ * MEMP_NUM_SNMP_VALUE: the number of OID or values concurrently used
+ * (does not have to be changed normally) - 3 of these are used per request
+ * (1 for the value read and 2 for OIDs - input and output)
+ */
+#ifndef MEMP_NUM_SNMP_VALUE
+#define MEMP_NUM_SNMP_VALUE             3
+#endif
+
+/**
+ * MEMP_NUM_NETDB: the number of concurrently running lwip_addrinfo() calls
+ * (before freeing the corresponding memory using lwip_freeaddrinfo()).
+ */
+#ifndef MEMP_NUM_NETDB
+#define MEMP_NUM_NETDB                  1
+#endif
+
+/**
+ * MEMP_NUM_LOCALHOSTLIST: the number of host entries in the local host list
+ * if DNS_LOCAL_HOSTLIST_IS_DYNAMIC==1.
+ */
+#ifndef MEMP_NUM_LOCALHOSTLIST
+#define MEMP_NUM_LOCALHOSTLIST          1
+#endif
+
+/**
+ * MEMP_NUM_PPPOE_INTERFACES: the number of concurrently active PPPoE
+ * interfaces (only used with PPPOE_SUPPORT==1)
+ */
+#ifndef MEMP_NUM_PPPOE_INTERFACES
+#define MEMP_NUM_PPPOE_INTERFACES       1
+#endif
+
+/**
+ * PBUF_POOL_SIZE: the number of buffers in the pbuf pool. 
+ */
+#ifndef PBUF_POOL_SIZE
+#define PBUF_POOL_SIZE                  16
+#endif
+
+/*
+   ---------------------------------
+   ---------- ARP options ----------
+   ---------------------------------
+*/
+/**
+ * LWIP_ARP==1: Enable ARP functionality.
+ */
+#ifndef LWIP_ARP
+#define LWIP_ARP                        1
+#endif
+
+/**
+ * ARP_TABLE_SIZE: Number of active MAC-IP address pairs cached.
+ */
+#ifndef ARP_TABLE_SIZE
+#define ARP_TABLE_SIZE                  10
+#endif
+
+/**
+ * ARP_QUEUEING==1: Multiple outgoing packets are queued during hardware address
+ * resolution. By default, only the most recent packet is queued per IP address.
+ * This is sufficient for most protocols and mainly reduces TCP connection
+ * startup time. Set this to 1 if you know your application sends more than one
+ * packet in a row to an IP address that is not in the ARP cache.
+ */
+#ifndef ARP_QUEUEING
+#define ARP_QUEUEING                    0
+#endif
+
+/**
+ * ETHARP_TRUST_IP_MAC==1: Incoming IP packets cause the ARP table to be
+ * updated with the source MAC and IP addresses supplied in the packet.
+ * You may want to disable this if you do not trust LAN peers to have the
+ * correct addresses, or as a limited approach to attempt to handle
+ * spoofing. If disabled, lwIP will need to make a new ARP request if
+ * the peer is not already in the ARP table, adding a little latency.
+ * The peer *is* in the ARP table if it requested our address before.
+ * Also notice that this slows down input processing of every IP packet!
+ */
+#ifndef ETHARP_TRUST_IP_MAC
+#define ETHARP_TRUST_IP_MAC             0
+#endif
+
+/**
+ * ETHARP_SUPPORT_VLAN==1: support receiving ethernet packets with VLAN header.
+ * Additionally, you can define ETHARP_VLAN_CHECK to an u16_t VLAN ID to check.
+ * If ETHARP_VLAN_CHECK is defined, only VLAN-traffic for this VLAN is accepted.
+ * If ETHARP_VLAN_CHECK is not defined, all traffic is accepted.
+ */
+#ifndef ETHARP_SUPPORT_VLAN
+#define ETHARP_SUPPORT_VLAN             0
+#endif
+
+/** LWIP_ETHERNET==1: enable ethernet support for PPPoE even though ARP
+ * might be disabled
+ */
+#ifndef LWIP_ETHERNET
+#define LWIP_ETHERNET                   (LWIP_ARP || PPPOE_SUPPORT)
+#endif
+
+/** ETH_PAD_SIZE: number of bytes added before the ethernet header to ensure
+ * alignment of payload after that header. Since the header is 14 bytes long,
+ * without this padding e.g. addresses in the IP header will not be aligned
+ * on a 32-bit boundary, so setting this to 2 can speed up 32-bit-platforms.
+ */
+#ifndef ETH_PAD_SIZE
+#define ETH_PAD_SIZE                    0
+#endif
+
+/** ETHARP_SUPPORT_STATIC_ENTRIES==1: enable code to support static ARP table
+ * entries (using etharp_add_static_entry/etharp_remove_static_entry).
+ */
+#ifndef ETHARP_SUPPORT_STATIC_ENTRIES
+#define ETHARP_SUPPORT_STATIC_ENTRIES   0
+#endif
+
+
+/*
+   --------------------------------
+   ---------- IP options ----------
+   --------------------------------
+*/
+/**
+ * IP_FORWARD==1: Enables the ability to forward IP packets across network
+ * interfaces. If you are going to run lwIP on a device with only one network
+ * interface, define this to 0.
+ */
+#ifndef IP_FORWARD
+#define IP_FORWARD                      0
+#endif
+
+/**
+ * IP_OPTIONS_ALLOWED: Defines the behavior for IP options.
+ *      IP_OPTIONS_ALLOWED==0: All packets with IP options are dropped.
+ *      IP_OPTIONS_ALLOWED==1: IP options are allowed (but not parsed).
+ */
+#ifndef IP_OPTIONS_ALLOWED
+#define IP_OPTIONS_ALLOWED              1
+#endif
+
+/**
+ * IP_REASSEMBLY==1: Reassemble incoming fragmented IP packets. Note that
+ * this option does not affect outgoing packet sizes, which can be controlled
+ * via IP_FRAG.
+ */
+#ifndef IP_REASSEMBLY
+#define IP_REASSEMBLY                   1
+#endif
+
+/**
+ * IP_FRAG==1: Fragment outgoing IP packets if their size exceeds MTU. Note
+ * that this option does not affect incoming packet sizes, which can be
+ * controlled via IP_REASSEMBLY.
+ */
+#ifndef IP_FRAG
+#define IP_FRAG                         1
+#endif
+
+/**
+ * IP_REASS_MAXAGE: Maximum time (in multiples of IP_TMR_INTERVAL - so seconds, normally)
+ * a fragmented IP packet waits for all fragments to arrive. If not all fragments arrived
+ * in this time, the whole packet is discarded.
+ */
+#ifndef IP_REASS_MAXAGE
+#define IP_REASS_MAXAGE                 3
+#endif
+
+/**
+ * IP_REASS_MAX_PBUFS: Total maximum amount of pbufs waiting to be reassembled.
+ * Since the received pbufs are enqueued, be sure to configure
+ * PBUF_POOL_SIZE > IP_REASS_MAX_PBUFS so that the stack is still able to receive
+ * packets even if the maximum amount of fragments is enqueued for reassembly!
+ */
+#ifndef IP_REASS_MAX_PBUFS
+#define IP_REASS_MAX_PBUFS              10
+#endif
+
+/**
+ * IP_FRAG_USES_STATIC_BUF==1: Use a static MTU-sized buffer for IP
+ * fragmentation. Otherwise pbufs are allocated and reference the original
+ * packet data to be fragmented (or with LWIP_NETIF_TX_SINGLE_PBUF==1,
+ * new PBUF_RAM pbufs are used for fragments).
+ * ATTENTION: IP_FRAG_USES_STATIC_BUF==1 may not be used for DMA-enabled MACs!
+ */
+#ifndef IP_FRAG_USES_STATIC_BUF
+#define IP_FRAG_USES_STATIC_BUF         0
+#endif
+
+/**
+ * IP_FRAG_MAX_MTU: Assumed max MTU on any interface for IP frag buffer
+ * (requires IP_FRAG_USES_STATIC_BUF==1)
+ */
+#if IP_FRAG_USES_STATIC_BUF && !defined(IP_FRAG_MAX_MTU)
+#define IP_FRAG_MAX_MTU                 1500
+#endif
+
+/**
+ * IP_DEFAULT_TTL: Default value for Time-To-Live used by transport layers.
+ */
+#ifndef IP_DEFAULT_TTL
+#define IP_DEFAULT_TTL                  255
+#endif
+
+/**
+ * IP_SOF_BROADCAST=1: Use the SOF_BROADCAST field to enable broadcast
+ * filter per pcb on udp and raw send operations. To enable broadcast filter
+ * on recv operations, you also have to set IP_SOF_BROADCAST_RECV=1.
+ */
+#ifndef IP_SOF_BROADCAST
+#define IP_SOF_BROADCAST                0
+#endif
+
+/**
+ * IP_SOF_BROADCAST_RECV (requires IP_SOF_BROADCAST=1) enable the broadcast
+ * filter on recv operations.
+ */
+#ifndef IP_SOF_BROADCAST_RECV
+#define IP_SOF_BROADCAST_RECV           0
+#endif
+
+/*
+   ----------------------------------
+   ---------- ICMP options ----------
+   ----------------------------------
+*/
+/**
+ * LWIP_ICMP==1: Enable ICMP module inside the IP stack.
+ * Be careful, disable that make your product non-compliant to RFC1122
+ */
+#ifndef LWIP_ICMP
+#define LWIP_ICMP                       1
+#endif
+
+/**
+ * ICMP_TTL: Default value for Time-To-Live used by ICMP packets.
+ */
+#ifndef ICMP_TTL
+#define ICMP_TTL                       (IP_DEFAULT_TTL)
+#endif
+
+/**
+ * LWIP_BROADCAST_PING==1: respond to broadcast pings (default is unicast only)
+ */
+#ifndef LWIP_BROADCAST_PING
+#define LWIP_BROADCAST_PING             0
+#endif
+
+/**
+ * LWIP_MULTICAST_PING==1: respond to multicast pings (default is unicast only)
+ */
+#ifndef LWIP_MULTICAST_PING
+#define LWIP_MULTICAST_PING             0
+#endif
+
+/*
+   ---------------------------------
+   ---------- RAW options ----------
+   ---------------------------------
+*/
+/**
+ * LWIP_RAW==1: Enable application layer to hook into the IP layer itself.
+ */
+#ifndef LWIP_RAW
+#define LWIP_RAW                        1
+#endif
+
+/**
+ * LWIP_RAW==1: Enable application layer to hook into the IP layer itself.
+ */
+#ifndef RAW_TTL
+#define RAW_TTL                        (IP_DEFAULT_TTL)
+#endif
+
+/*
+   ----------------------------------
+   ---------- DHCP options ----------
+   ----------------------------------
+*/
+/**
+ * LWIP_DHCP==1: Enable DHCP module.
+ */
+#ifndef LWIP_DHCP
+#define LWIP_DHCP                       0
+#endif
+
+/**
+ * DHCP_DOES_ARP_CHECK==1: Do an ARP check on the offered address.
+ */
+#ifndef DHCP_DOES_ARP_CHECK
+#define DHCP_DOES_ARP_CHECK             ((LWIP_DHCP) && (LWIP_ARP))
+#endif
+
+/*
+   ------------------------------------
+   ---------- AUTOIP options ----------
+   ------------------------------------
+*/
+/**
+ * LWIP_AUTOIP==1: Enable AUTOIP module.
+ */
+#ifndef LWIP_AUTOIP
+#define LWIP_AUTOIP                     0
+#endif
+
+/**
+ * LWIP_DHCP_AUTOIP_COOP==1: Allow DHCP and AUTOIP to be both enabled on
+ * the same interface at the same time.
+ */
+#ifndef LWIP_DHCP_AUTOIP_COOP
+#define LWIP_DHCP_AUTOIP_COOP           0
+#endif
+
+/**
+ * LWIP_DHCP_AUTOIP_COOP_TRIES: Set to the number of DHCP DISCOVER probes
+ * that should be sent before falling back on AUTOIP. This can be set
+ * as low as 1 to get an AutoIP address very quickly, but you should
+ * be prepared to handle a changing IP address when DHCP overrides
+ * AutoIP.
+ */
+#ifndef LWIP_DHCP_AUTOIP_COOP_TRIES
+#define LWIP_DHCP_AUTOIP_COOP_TRIES     9
+#endif
+
+/*
+   ----------------------------------
+   ---------- SNMP options ----------
+   ----------------------------------
+*/
+/**
+ * LWIP_SNMP==1: Turn on SNMP module. UDP must be available for SNMP
+ * transport.
+ */
+#ifndef LWIP_SNMP
+#define LWIP_SNMP                       0
+#endif
+
+/**
+ * SNMP_CONCURRENT_REQUESTS: Number of concurrent requests the module will
+ * allow. At least one request buffer is required.
+ * Does not have to be changed unless external MIBs answer request asynchronously
+ */
+#ifndef SNMP_CONCURRENT_REQUESTS
+#define SNMP_CONCURRENT_REQUESTS        1
+#endif
+
+/**
+ * SNMP_TRAP_DESTINATIONS: Number of trap destinations. At least one trap
+ * destination is required
+ */
+#ifndef SNMP_TRAP_DESTINATIONS
+#define SNMP_TRAP_DESTINATIONS          1
+#endif
+
+/**
+ * SNMP_PRIVATE_MIB: 
+ * When using a private MIB, you have to create a file 'private_mib.h' that contains
+ * a 'struct mib_array_node mib_private' which contains your MIB.
+ */
+#ifndef SNMP_PRIVATE_MIB
+#define SNMP_PRIVATE_MIB                0
+#endif
+
+/**
+ * Only allow SNMP write actions that are 'safe' (e.g. disabeling netifs is not
+ * a safe action and disabled when SNMP_SAFE_REQUESTS = 1).
+ * Unsafe requests are disabled by default!
+ */
+#ifndef SNMP_SAFE_REQUESTS
+#define SNMP_SAFE_REQUESTS              1
+#endif
+
+/**
+ * The maximum length of strings used. This affects the size of
+ * MEMP_SNMP_VALUE elements.
+ */
+#ifndef SNMP_MAX_OCTET_STRING_LEN
+#define SNMP_MAX_OCTET_STRING_LEN       127
+#endif
+
+/**
+ * The maximum depth of the SNMP tree.
+ * With private MIBs enabled, this depends on your MIB!
+ * This affects the size of MEMP_SNMP_VALUE elements.
+ */
+#ifndef SNMP_MAX_TREE_DEPTH
+#define SNMP_MAX_TREE_DEPTH             15
+#endif
+
+/**
+ * The size of the MEMP_SNMP_VALUE elements, normally calculated from
+ * SNMP_MAX_OCTET_STRING_LEN and SNMP_MAX_TREE_DEPTH.
+ */
+#ifndef SNMP_MAX_VALUE_SIZE
+#define SNMP_MAX_VALUE_SIZE             LWIP_MAX((SNMP_MAX_OCTET_STRING_LEN)+1, sizeof(s32_t)*(SNMP_MAX_TREE_DEPTH))
+#endif
+
+/*
+   ----------------------------------
+   ---------- IGMP options ----------
+   ----------------------------------
+*/
+/**
+ * LWIP_IGMP==1: Turn on IGMP module. 
+ */
+#ifndef LWIP_IGMP
+#define LWIP_IGMP                       0
+#endif
+
+/*
+   ----------------------------------
+   ---------- DNS options -----------
+   ----------------------------------
+*/
+/**
+ * LWIP_DNS==1: Turn on DNS module. UDP must be available for DNS
+ * transport.
+ */
+#ifndef LWIP_DNS
+#define LWIP_DNS                        0
+#endif
+
+/** DNS maximum number of entries to maintain locally. */
+#ifndef DNS_TABLE_SIZE
+#define DNS_TABLE_SIZE                  4
+#endif
+
+/** DNS maximum host name length supported in the name table. */
+#ifndef DNS_MAX_NAME_LENGTH
+#define DNS_MAX_NAME_LENGTH             256
+#endif
+
+/** The maximum of DNS servers */
+#ifndef DNS_MAX_SERVERS
+#define DNS_MAX_SERVERS                 2
+#endif
+
+/** DNS do a name checking between the query and the response. */
+#ifndef DNS_DOES_NAME_CHECK
+#define DNS_DOES_NAME_CHECK             1
+#endif
+
+/** DNS message max. size. Default value is RFC compliant. */
+#ifndef DNS_MSG_SIZE
+#define DNS_MSG_SIZE                    512
+#endif
+
+/** DNS_LOCAL_HOSTLIST: Implements a local host-to-address list. If enabled,
+ *  you have to define
+ *    #define DNS_LOCAL_HOSTLIST_INIT {{"host1", 0x123}, {"host2", 0x234}}
+ *  (an array of structs name/address, where address is an u32_t in network
+ *  byte order).
+ *
+ *  Instead, you can also use an external function:
+ *  #define DNS_LOOKUP_LOCAL_EXTERN(x) extern u32_t my_lookup_function(const char *name)
+ *  that returns the IP address or INADDR_NONE if not found.
+ */
+#ifndef DNS_LOCAL_HOSTLIST
+#define DNS_LOCAL_HOSTLIST              0
+#endif /* DNS_LOCAL_HOSTLIST */
+
+/** If this is turned on, the local host-list can be dynamically changed
+ *  at runtime. */
+#ifndef DNS_LOCAL_HOSTLIST_IS_DYNAMIC
+#define DNS_LOCAL_HOSTLIST_IS_DYNAMIC   0
+#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
+
+/*
+   ---------------------------------
+   ---------- UDP options ----------
+   ---------------------------------
+*/
+/**
+ * LWIP_UDP==1: Turn on UDP.
+ */
+#ifndef LWIP_UDP
+#define LWIP_UDP                        1
+#endif
+
+/**
+ * LWIP_UDPLITE==1: Turn on UDP-Lite. (Requires LWIP_UDP)
+ */
+#ifndef LWIP_UDPLITE
+#define LWIP_UDPLITE                    0
+#endif
+
+/**
+ * UDP_TTL: Default Time-To-Live value.
+ */
+#ifndef UDP_TTL
+#define UDP_TTL                         (IP_DEFAULT_TTL)
+#endif
+
+/**
+ * LWIP_NETBUF_RECVINFO==1: append destination addr and port to every netbuf.
+ */
+#ifndef LWIP_NETBUF_RECVINFO
+#define LWIP_NETBUF_RECVINFO            0
+#endif
+
+/*
+   ---------------------------------
+   ---------- TCP options ----------
+   ---------------------------------
+*/
+/**
+ * LWIP_TCP==1: Turn on TCP.
+ */
+#ifndef LWIP_TCP
+#define LWIP_TCP                        1
+#endif
+
+/**
+ * TCP_TTL: Default Time-To-Live value.
+ */
+#ifndef TCP_TTL
+#define TCP_TTL                         (IP_DEFAULT_TTL)
+#endif
+
+/**
+ * TCP_WND: The size of a TCP window.  This must be at least 
+ * (2 * TCP_MSS) for things to work well
+ */
+#ifndef TCP_WND
+#define TCP_WND                         (4 * TCP_MSS)
+#endif 
+
+/**
+ * TCP_MAXRTX: Maximum number of retransmissions of data segments.
+ */
+#ifndef TCP_MAXRTX
+#define TCP_MAXRTX                      12
+#endif
+
+/**
+ * TCP_SYNMAXRTX: Maximum number of retransmissions of SYN segments.
+ */
+#ifndef TCP_SYNMAXRTX
+#define TCP_SYNMAXRTX                   6
+#endif
+
+/**
+ * TCP_QUEUE_OOSEQ==1: TCP will queue segments that arrive out of order.
+ * Define to 0 if your device is low on memory.
+ */
+#ifndef TCP_QUEUE_OOSEQ
+#define TCP_QUEUE_OOSEQ                 (LWIP_TCP)
+#endif
+
+/**
+ * TCP_MSS: TCP Maximum segment size. (default is 536, a conservative default,
+ * you might want to increase this.)
+ * For the receive side, this MSS is advertised to the remote side
+ * when opening a connection. For the transmit size, this MSS sets
+ * an upper limit on the MSS advertised by the remote host.
+ */
+#ifndef TCP_MSS
+#define TCP_MSS                         536
+#endif
+
+/**
+ * TCP_CALCULATE_EFF_SEND_MSS: "The maximum size of a segment that TCP really
+ * sends, the 'effective send MSS,' MUST be the smaller of the send MSS (which
+ * reflects the available reassembly buffer size at the remote host) and the
+ * largest size permitted by the IP layer" (RFC 1122)
+ * Setting this to 1 enables code that checks TCP_MSS against the MTU of the
+ * netif used for a connection and limits the MSS if it would be too big otherwise.
+ */
+#ifndef TCP_CALCULATE_EFF_SEND_MSS
+#define TCP_CALCULATE_EFF_SEND_MSS      1
+#endif
+
+
+/**
+ * TCP_SND_BUF: TCP sender buffer space (bytes). 
+ */
+#ifndef TCP_SND_BUF
+#define TCP_SND_BUF                     256
+#endif
+
+/**
+ * TCP_SND_QUEUELEN: TCP sender buffer space (pbufs). This must be at least
+ * as much as (2 * TCP_SND_BUF/TCP_MSS) for things to work.
+ */
+#ifndef TCP_SND_QUEUELEN
+#define TCP_SND_QUEUELEN                ((4 * (TCP_SND_BUF) + (TCP_MSS - 1))/(TCP_MSS))
+#endif
+
+/**
+ * TCP_SNDLOWAT: TCP writable space (bytes). This must be less than
+ * TCP_SND_BUF. It is the amount of space which must be available in the
+ * TCP snd_buf for select to return writable (combined with TCP_SNDQUEUELOWAT).
+ */
+#ifndef TCP_SNDLOWAT
+#define TCP_SNDLOWAT                    ((TCP_SND_BUF)/2)
+#endif
+
+/**
+ * TCP_SNDQUEUELOWAT: TCP writable bufs (pbuf count). This must be grater
+ * than TCP_SND_QUEUELEN. If the number of pbufs queued on a pcb drops below
+ * this number, select returns writable (combined with TCP_SNDLOWAT).
+ */
+#ifndef TCP_SNDQUEUELOWAT
+#define TCP_SNDQUEUELOWAT               ((TCP_SND_QUEUELEN)/2)
+#endif
+
+/**
+ * TCP_LISTEN_BACKLOG: Enable the backlog option for tcp listen pcb.
+ */
+#ifndef TCP_LISTEN_BACKLOG
+#define TCP_LISTEN_BACKLOG              0
+#endif
+
+/**
+ * The maximum allowed backlog for TCP listen netconns.
+ * This backlog is used unless another is explicitly specified.
+ * 0xff is the maximum (u8_t).
+ */
+#ifndef TCP_DEFAULT_LISTEN_BACKLOG
+#define TCP_DEFAULT_LISTEN_BACKLOG      0xff
+#endif
+
+/**
+ * TCP_OVERSIZE: The maximum number of bytes that tcp_write may
+ * allocate ahead of time in an attempt to create shorter pbuf chains
+ * for transmission. The meaningful range is 0 to TCP_MSS. Some
+ * suggested values are:
+ *
+ * 0:         Disable oversized allocation. Each tcp_write() allocates a new
+              pbuf (old behaviour).
+ * 1:         Allocate size-aligned pbufs with minimal excess. Use this if your
+ *            scatter-gather DMA requires aligned fragments.
+ * 128:       Limit the pbuf/memory overhead to 20%.
+ * TCP_MSS:   Try to create unfragmented TCP packets.
+ * TCP_MSS/4: Try to create 4 fragments or less per TCP packet.
+ */
+#ifndef TCP_OVERSIZE
+#define TCP_OVERSIZE                    TCP_MSS
+#endif
+
+/**
+ * LWIP_TCP_TIMESTAMPS==1: support the TCP timestamp option.
+ */
+#ifndef LWIP_TCP_TIMESTAMPS
+#define LWIP_TCP_TIMESTAMPS             0
+#endif
+
+/**
+ * TCP_WND_UPDATE_THRESHOLD: difference in window to trigger an
+ * explicit window update
+ */
+#ifndef TCP_WND_UPDATE_THRESHOLD
+#define TCP_WND_UPDATE_THRESHOLD   (TCP_WND / 4)
+#endif
+
+/**
+ * LWIP_EVENT_API and LWIP_CALLBACK_API: Only one of these should be set to 1.
+ *     LWIP_EVENT_API==1: The user defines lwip_tcp_event() to receive all
+ *         events (accept, sent, etc) that happen in the system.
+ *     LWIP_CALLBACK_API==1: The PCB callback function is called directly
+ *         for the event.
+ */
+#ifndef LWIP_EVENT_API
+#define LWIP_EVENT_API                  0
+#define LWIP_CALLBACK_API               1
+#else 
+#define LWIP_EVENT_API                  1
+#define LWIP_CALLBACK_API               0
+#endif
+
+
+/*
+   ----------------------------------
+   ---------- Pbuf options ----------
+   ----------------------------------
+*/
+/**
+ * PBUF_LINK_HLEN: the number of bytes that should be allocated for a
+ * link level header. The default is 14, the standard value for
+ * Ethernet.
+ */
+#ifndef PBUF_LINK_HLEN
+#define PBUF_LINK_HLEN                  (14 + ETH_PAD_SIZE)
+#endif
+
+/**
+ * PBUF_POOL_BUFSIZE: the size of each pbuf in the pbuf pool. The default is
+ * designed to accomodate single full size TCP frame in one pbuf, including
+ * TCP_MSS, IP header, and link header.
+ */
+#ifndef PBUF_POOL_BUFSIZE
+#define PBUF_POOL_BUFSIZE               LWIP_MEM_ALIGN_SIZE(TCP_MSS+40+PBUF_LINK_HLEN)
+#endif
+
+/*
+   ------------------------------------------------
+   ---------- Network Interfaces options ----------
+   ------------------------------------------------
+*/
+/**
+ * LWIP_NETIF_HOSTNAME==1: use DHCP_OPTION_HOSTNAME with netif's hostname
+ * field.
+ */
+#ifndef LWIP_NETIF_HOSTNAME
+#define LWIP_NETIF_HOSTNAME             0
+#endif
+
+/**
+ * LWIP_NETIF_API==1: Support netif api (in netifapi.c)
+ */
+#ifndef LWIP_NETIF_API
+#define LWIP_NETIF_API                  0
+#endif
+
+/**
+ * LWIP_NETIF_STATUS_CALLBACK==1: Support a callback function whenever an interface
+ * changes its up/down status (i.e., due to DHCP IP acquistion)
+ */
+#ifndef LWIP_NETIF_STATUS_CALLBACK
+#define LWIP_NETIF_STATUS_CALLBACK      0
+#endif
+
+/**
+ * LWIP_NETIF_LINK_CALLBACK==1: Support a callback function from an interface
+ * whenever the link changes (i.e., link down)
+ */
+#ifndef LWIP_NETIF_LINK_CALLBACK
+#define LWIP_NETIF_LINK_CALLBACK        0
+#endif
+
+/**
+ * LWIP_NETIF_HWADDRHINT==1: Cache link-layer-address hints (e.g. table
+ * indices) in struct netif. TCP and UDP can make use of this to prevent
+ * scanning the ARP table for every sent packet. While this is faster for big
+ * ARP tables or many concurrent connections, it might be counterproductive
+ * if you have a tiny ARP table or if there never are concurrent connections.
+ */
+#ifndef LWIP_NETIF_HWADDRHINT
+#define LWIP_NETIF_HWADDRHINT           0
+#endif
+
+/**
+ * LWIP_NETIF_LOOPBACK==1: Support sending packets with a destination IP
+ * address equal to the netif IP address, looping them back up the stack.
+ */
+#ifndef LWIP_NETIF_LOOPBACK
+#define LWIP_NETIF_LOOPBACK             0
+#endif
+
+/**
+ * LWIP_LOOPBACK_MAX_PBUFS: Maximum number of pbufs on queue for loopback
+ * sending for each netif (0 = disabled)
+ */
+#ifndef LWIP_LOOPBACK_MAX_PBUFS
+#define LWIP_LOOPBACK_MAX_PBUFS         0
+#endif
+
+/**
+ * LWIP_NETIF_LOOPBACK_MULTITHREADING: Indicates whether threading is enabled in
+ * the system, as netifs must change how they behave depending on this setting
+ * for the LWIP_NETIF_LOOPBACK option to work.
+ * Setting this is needed to avoid reentering non-reentrant functions like
+ * tcp_input().
+ *    LWIP_NETIF_LOOPBACK_MULTITHREADING==1: Indicates that the user is using a
+ *       multithreaded environment like tcpip.c. In this case, netif->input()
+ *       is called directly.
+ *    LWIP_NETIF_LOOPBACK_MULTITHREADING==0: Indicates a polling (or NO_SYS) setup.
+ *       The packets are put on a list and netif_poll() must be called in
+ *       the main application loop.
+ */
+#ifndef LWIP_NETIF_LOOPBACK_MULTITHREADING
+#define LWIP_NETIF_LOOPBACK_MULTITHREADING    (!NO_SYS)
+#endif
+
+/**
+ * LWIP_NETIF_TX_SINGLE_PBUF: if this is set to 1, lwIP tries to put all data
+ * to be sent into one single pbuf. This is for compatibility with DMA-enabled
+ * MACs that do not support scatter-gather.
+ * Beware that this might involve CPU-memcpy before transmitting that would not
+ * be needed without this flag! Use this only if you need to!
+ *
+ * @todo: TCP and IP-frag do not work with this, yet:
+ */
+#ifndef LWIP_NETIF_TX_SINGLE_PBUF
+#define LWIP_NETIF_TX_SINGLE_PBUF             0
+#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
+
+/*
+   ------------------------------------
+   ---------- LOOPIF options ----------
+   ------------------------------------
+*/
+/**
+ * LWIP_HAVE_LOOPIF==1: Support loop interface (127.0.0.1) and loopif.c
+ */
+#ifndef LWIP_HAVE_LOOPIF
+#define LWIP_HAVE_LOOPIF                0
+#endif
+
+/*
+   ------------------------------------
+   ---------- SLIPIF options ----------
+   ------------------------------------
+*/
+/**
+ * LWIP_HAVE_SLIPIF==1: Support slip interface and slipif.c
+ */
+#ifndef LWIP_HAVE_SLIPIF
+#define LWIP_HAVE_SLIPIF                0
+#endif
+
+/*
+   ------------------------------------
+   ---------- Thread options ----------
+   ------------------------------------
+*/
+/**
+ * TCPIP_THREAD_NAME: The name assigned to the main tcpip thread.
+ */
+#ifndef TCPIP_THREAD_NAME
+#define TCPIP_THREAD_NAME              "tcpip_thread"
+#endif
+
+/**
+ * TCPIP_THREAD_STACKSIZE: The stack size used by the main tcpip thread.
+ * The stack size value itself is platform-dependent, but is passed to
+ * sys_thread_new() when the thread is created.
+ */
+#ifndef TCPIP_THREAD_STACKSIZE
+#define TCPIP_THREAD_STACKSIZE          0
+#endif
+
+/**
+ * TCPIP_THREAD_PRIO: The priority assigned to the main tcpip thread.
+ * The priority value itself is platform-dependent, but is passed to
+ * sys_thread_new() when the thread is created.
+ */
+#ifndef TCPIP_THREAD_PRIO
+#define TCPIP_THREAD_PRIO               1
+#endif
+
+/**
+ * TCPIP_MBOX_SIZE: The mailbox size for the tcpip thread messages
+ * The queue size value itself is platform-dependent, but is passed to
+ * sys_mbox_new() when tcpip_init is called.
+ */
+#ifndef TCPIP_MBOX_SIZE
+#define TCPIP_MBOX_SIZE                 0
+#endif
+
+/**
+ * SLIPIF_THREAD_NAME: The name assigned to the slipif_loop thread.
+ */
+#ifndef SLIPIF_THREAD_NAME
+#define SLIPIF_THREAD_NAME             "slipif_loop"
+#endif
+
+/**
+ * SLIP_THREAD_STACKSIZE: The stack size used by the slipif_loop thread.
+ * The stack size value itself is platform-dependent, but is passed to
+ * sys_thread_new() when the thread is created.
+ */
+#ifndef SLIPIF_THREAD_STACKSIZE
+#define SLIPIF_THREAD_STACKSIZE         0
+#endif
+
+/**
+ * SLIPIF_THREAD_PRIO: The priority assigned to the slipif_loop thread.
+ * The priority value itself is platform-dependent, but is passed to
+ * sys_thread_new() when the thread is created.
+ */
+#ifndef SLIPIF_THREAD_PRIO
+#define SLIPIF_THREAD_PRIO              1
+#endif
+
+/**
+ * PPP_THREAD_NAME: The name assigned to the pppInputThread.
+ */
+#ifndef PPP_THREAD_NAME
+#define PPP_THREAD_NAME                "pppInputThread"
+#endif
+
+/**
+ * PPP_THREAD_STACKSIZE: The stack size used by the pppInputThread.
+ * The stack size value itself is platform-dependent, but is passed to
+ * sys_thread_new() when the thread is created.
+ */
+#ifndef PPP_THREAD_STACKSIZE
+#define PPP_THREAD_STACKSIZE            0
+#endif
+
+/**
+ * PPP_THREAD_PRIO: The priority assigned to the pppInputThread.
+ * The priority value itself is platform-dependent, but is passed to
+ * sys_thread_new() when the thread is created.
+ */
+#ifndef PPP_THREAD_PRIO
+#define PPP_THREAD_PRIO                 1
+#endif
+
+/**
+ * DEFAULT_THREAD_NAME: The name assigned to any other lwIP thread.
+ */
+#ifndef DEFAULT_THREAD_NAME
+#define DEFAULT_THREAD_NAME            "lwIP"
+#endif
+
+/**
+ * DEFAULT_THREAD_STACKSIZE: The stack size used by any other lwIP thread.
+ * The stack size value itself is platform-dependent, but is passed to
+ * sys_thread_new() when the thread is created.
+ */
+#ifndef DEFAULT_THREAD_STACKSIZE
+#define DEFAULT_THREAD_STACKSIZE        0
+#endif
+
+/**
+ * DEFAULT_THREAD_PRIO: The priority assigned to any other lwIP thread.
+ * The priority value itself is platform-dependent, but is passed to
+ * sys_thread_new() when the thread is created.
+ */
+#ifndef DEFAULT_THREAD_PRIO
+#define DEFAULT_THREAD_PRIO             1
+#endif
+
+/**
+ * DEFAULT_RAW_RECVMBOX_SIZE: The mailbox size for the incoming packets on a
+ * NETCONN_RAW. The queue size value itself is platform-dependent, but is passed
+ * to sys_mbox_new() when the recvmbox is created.
+ */
+#ifndef DEFAULT_RAW_RECVMBOX_SIZE
+#define DEFAULT_RAW_RECVMBOX_SIZE       0
+#endif
+
+/**
+ * DEFAULT_UDP_RECVMBOX_SIZE: The mailbox size for the incoming packets on a
+ * NETCONN_UDP. The queue size value itself is platform-dependent, but is passed
+ * to sys_mbox_new() when the recvmbox is created.
+ */
+#ifndef DEFAULT_UDP_RECVMBOX_SIZE
+#define DEFAULT_UDP_RECVMBOX_SIZE       0
+#endif
+
+/**
+ * DEFAULT_TCP_RECVMBOX_SIZE: The mailbox size for the incoming packets on a
+ * NETCONN_TCP. The queue size value itself is platform-dependent, but is passed
+ * to sys_mbox_new() when the recvmbox is created.
+ */
+#ifndef DEFAULT_TCP_RECVMBOX_SIZE
+#define DEFAULT_TCP_RECVMBOX_SIZE       0
+#endif
+
+/**
+ * DEFAULT_ACCEPTMBOX_SIZE: The mailbox size for the incoming connections.
+ * The queue size value itself is platform-dependent, but is passed to
+ * sys_mbox_new() when the acceptmbox is created.
+ */
+#ifndef DEFAULT_ACCEPTMBOX_SIZE
+#define DEFAULT_ACCEPTMBOX_SIZE         0
+#endif
+
+/*
+   ----------------------------------------------
+   ---------- Sequential layer options ----------
+   ----------------------------------------------
+*/
+/**
+ * LWIP_TCPIP_CORE_LOCKING: (EXPERIMENTAL!)
+ * Don't use it if you're not an active lwIP project member
+ */
+#ifndef LWIP_TCPIP_CORE_LOCKING
+#define LWIP_TCPIP_CORE_LOCKING         0
+#endif
+
+/**
+ * LWIP_TCPIP_CORE_LOCKING_INPUT: (EXPERIMENTAL!)
+ * Don't use it if you're not an active lwIP project member
+ */
+#ifndef LWIP_TCPIP_CORE_LOCKING_INPUT
+#define LWIP_TCPIP_CORE_LOCKING_INPUT   0
+#endif
+
+/**
+ * LWIP_NETCONN==1: Enable Netconn API (require to use api_lib.c)
+ */
+#ifndef LWIP_NETCONN
+#define LWIP_NETCONN                    1
+#endif
+
+/** LWIP_TCPIP_TIMEOUT==1: Enable tcpip_timeout/tcpip_untimeout tod create
+ * timers running in tcpip_thread from another thread.
+ */
+#ifndef LWIP_TCPIP_TIMEOUT
+#define LWIP_TCPIP_TIMEOUT              1
+#endif
+
+/*
+   ------------------------------------
+   ---------- Socket options ----------
+   ------------------------------------
+*/
+/**
+ * LWIP_SOCKET==1: Enable Socket API (require to use sockets.c)
+ */
+#ifndef LWIP_SOCKET
+#define LWIP_SOCKET                     1
+#endif
+
+/**
+ * LWIP_COMPAT_SOCKETS==1: Enable BSD-style sockets functions names.
+ * (only used if you use sockets.c)
+ */
+#ifndef LWIP_COMPAT_SOCKETS
+#define LWIP_COMPAT_SOCKETS             1
+#endif
+
+/**
+ * LWIP_POSIX_SOCKETS_IO_NAMES==1: Enable POSIX-style sockets functions names.
+ * Disable this option if you use a POSIX operating system that uses the same
+ * names (read, write & close). (only used if you use sockets.c)
+ */
+#ifndef LWIP_POSIX_SOCKETS_IO_NAMES
+#define LWIP_POSIX_SOCKETS_IO_NAMES     1
+#endif
+
+/**
+ * LWIP_TCP_KEEPALIVE==1: Enable TCP_KEEPIDLE, TCP_KEEPINTVL and TCP_KEEPCNT
+ * options processing. Note that TCP_KEEPIDLE and TCP_KEEPINTVL have to be set
+ * in seconds. (does not require sockets.c, and will affect tcp.c)
+ */
+#ifndef LWIP_TCP_KEEPALIVE
+#define LWIP_TCP_KEEPALIVE              0
+#endif
+
+/**
+ * LWIP_SO_RCVTIMEO==1: Enable SO_RCVTIMEO processing.
+ */
+#ifndef LWIP_SO_RCVTIMEO
+#define LWIP_SO_RCVTIMEO                0
+#endif
+
+/**
+ * LWIP_SO_RCVBUF==1: Enable SO_RCVBUF processing.
+ */
+#ifndef LWIP_SO_RCVBUF
+#define LWIP_SO_RCVBUF                  0
+#endif
+
+/**
+ * If LWIP_SO_RCVBUF is used, this is the default value for recv_bufsize.
+ */
+#ifndef RECV_BUFSIZE_DEFAULT
+#define RECV_BUFSIZE_DEFAULT            INT_MAX
+#endif
+
+/**
+ * SO_REUSE==1: Enable SO_REUSEADDR option.
+ */
+#ifndef SO_REUSE
+#define SO_REUSE                        0
+#endif
+
+/**
+ * SO_REUSE_RXTOALL==1: Pass a copy of incoming broadcast/multicast packets
+ * to all local matches if SO_REUSEADDR is turned on.
+ * WARNING: Adds a memcpy for every packet if passing to more than one pcb!
+ */
+#ifndef SO_REUSE_RXTOALL
+#define SO_REUSE_RXTOALL                0
+#endif
+
+/*
+   ----------------------------------------
+   ---------- Statistics options ----------
+   ----------------------------------------
+*/
+/**
+ * LWIP_STATS==1: Enable statistics collection in lwip_stats.
+ */
+#ifndef LWIP_STATS
+#define LWIP_STATS                      1
+#endif
+
+#if LWIP_STATS
+
+/**
+ * LWIP_STATS_DISPLAY==1: Compile in the statistics output functions.
+ */
+#ifndef LWIP_STATS_DISPLAY
+#define LWIP_STATS_DISPLAY              0
+#endif
+
+/**
+ * LINK_STATS==1: Enable link stats.
+ */
+#ifndef LINK_STATS
+#define LINK_STATS                      1
+#endif
+
+/**
+ * ETHARP_STATS==1: Enable etharp stats.
+ */
+#ifndef ETHARP_STATS
+#define ETHARP_STATS                    (LWIP_ARP)
+#endif
+
+/**
+ * IP_STATS==1: Enable IP stats.
+ */
+#ifndef IP_STATS
+#define IP_STATS                        1
+#endif
+
+/**
+ * IPFRAG_STATS==1: Enable IP fragmentation stats. Default is
+ * on if using either frag or reass.
+ */
+#ifndef IPFRAG_STATS
+#define IPFRAG_STATS                    (IP_REASSEMBLY || IP_FRAG)
+#endif
+
+/**
+ * ICMP_STATS==1: Enable ICMP stats.
+ */
+#ifndef ICMP_STATS
+#define ICMP_STATS                      1
+#endif
+
+/**
+ * IGMP_STATS==1: Enable IGMP stats.
+ */
+#ifndef IGMP_STATS
+#define IGMP_STATS                      (LWIP_IGMP)
+#endif
+
+/**
+ * UDP_STATS==1: Enable UDP stats. Default is on if
+ * UDP enabled, otherwise off.
+ */
+#ifndef UDP_STATS
+#define UDP_STATS                       (LWIP_UDP)
+#endif
+
+/**
+ * TCP_STATS==1: Enable TCP stats. Default is on if TCP
+ * enabled, otherwise off.
+ */
+#ifndef TCP_STATS
+#define TCP_STATS                       (LWIP_TCP)
+#endif
+
+/**
+ * MEM_STATS==1: Enable mem.c stats.
+ */
+#ifndef MEM_STATS
+#define MEM_STATS                       ((MEM_LIBC_MALLOC == 0) && (MEM_USE_POOLS == 0))
+#endif
+
+/**
+ * MEMP_STATS==1: Enable memp.c pool stats.
+ */
+#ifndef MEMP_STATS
+#define MEMP_STATS                      (MEMP_MEM_MALLOC == 0)
+#endif
+
+/**
+ * SYS_STATS==1: Enable system stats (sem and mbox counts, etc).
+ */
+#ifndef SYS_STATS
+#define SYS_STATS                       (NO_SYS == 0)
+#endif
+
+#else
+
+#define LINK_STATS                      0
+#define IP_STATS                        0
+#define IPFRAG_STATS                    0
+#define ICMP_STATS                      0
+#define IGMP_STATS                      0
+#define UDP_STATS                       0
+#define TCP_STATS                       0
+#define MEM_STATS                       0
+#define MEMP_STATS                      0
+#define SYS_STATS                       0
+#define LWIP_STATS_DISPLAY              0
+
+#endif /* LWIP_STATS */
+
+/*
+   ---------------------------------
+   ---------- PPP options ----------
+   ---------------------------------
+*/
+/**
+ * PPP_SUPPORT==1: Enable PPP.
+ */
+#ifndef PPP_SUPPORT
+#define PPP_SUPPORT                     0
+#endif
+
+/**
+ * PPPOE_SUPPORT==1: Enable PPP Over Ethernet
+ */
+#ifndef PPPOE_SUPPORT
+#define PPPOE_SUPPORT                   0
+#endif
+
+/**
+ * PPPOS_SUPPORT==1: Enable PPP Over Serial
+ */
+#ifndef PPPOS_SUPPORT
+#define PPPOS_SUPPORT                   PPP_SUPPORT
+#endif
+
+#if PPP_SUPPORT
+
+/**
+ * NUM_PPP: Max PPP sessions.
+ */
+#ifndef NUM_PPP
+#define NUM_PPP                         1
+#endif
+
+/**
+ * PAP_SUPPORT==1: Support PAP.
+ */
+#ifndef PAP_SUPPORT
+#define PAP_SUPPORT                     0
+#endif
+
+/**
+ * CHAP_SUPPORT==1: Support CHAP.
+ */
+#ifndef CHAP_SUPPORT
+#define CHAP_SUPPORT                    0
+#endif
+
+/**
+ * MSCHAP_SUPPORT==1: Support MSCHAP. CURRENTLY NOT SUPPORTED! DO NOT SET!
+ */
+#ifndef MSCHAP_SUPPORT
+#define MSCHAP_SUPPORT                  0
+#endif
+
+/**
+ * CBCP_SUPPORT==1: Support CBCP. CURRENTLY NOT SUPPORTED! DO NOT SET!
+ */
+#ifndef CBCP_SUPPORT
+#define CBCP_SUPPORT                    0
+#endif
+
+/**
+ * CCP_SUPPORT==1: Support CCP. CURRENTLY NOT SUPPORTED! DO NOT SET!
+ */
+#ifndef CCP_SUPPORT
+#define CCP_SUPPORT                     0
+#endif
+
+/**
+ * VJ_SUPPORT==1: Support VJ header compression.
+ */
+#ifndef VJ_SUPPORT
+#define VJ_SUPPORT                      0
+#endif
+
+/**
+ * MD5_SUPPORT==1: Support MD5 (see also CHAP).
+ */
+#ifndef MD5_SUPPORT
+#define MD5_SUPPORT                     0
+#endif
+
+/*
+ * Timeouts
+ */
+#ifndef FSM_DEFTIMEOUT
+#define FSM_DEFTIMEOUT                  6       /* Timeout time in seconds */
+#endif
+
+#ifndef FSM_DEFMAXTERMREQS
+#define FSM_DEFMAXTERMREQS              2       /* Maximum Terminate-Request transmissions */
+#endif
+
+#ifndef FSM_DEFMAXCONFREQS
+#define FSM_DEFMAXCONFREQS              10      /* Maximum Configure-Request transmissions */
+#endif
+
+#ifndef FSM_DEFMAXNAKLOOPS
+#define FSM_DEFMAXNAKLOOPS              5       /* Maximum number of nak loops */
+#endif
+
+#ifndef UPAP_DEFTIMEOUT
+#define UPAP_DEFTIMEOUT                 6       /* Timeout (seconds) for retransmitting req */
+#endif
+
+#ifndef UPAP_DEFREQTIME
+#define UPAP_DEFREQTIME                 30      /* Time to wait for auth-req from peer */
+#endif
+
+#ifndef CHAP_DEFTIMEOUT
+#define CHAP_DEFTIMEOUT                 6       /* Timeout time in seconds */
+#endif
+
+#ifndef CHAP_DEFTRANSMITS
+#define CHAP_DEFTRANSMITS               10      /* max # times to send challenge */
+#endif
+
+/* Interval in seconds between keepalive echo requests, 0 to disable. */
+#ifndef LCP_ECHOINTERVAL
+#define LCP_ECHOINTERVAL                0
+#endif
+
+/* Number of unanswered echo requests before failure. */
+#ifndef LCP_MAXECHOFAILS
+#define LCP_MAXECHOFAILS                3
+#endif
+
+/* Max Xmit idle time (in jiffies) before resend flag char. */
+#ifndef PPP_MAXIDLEFLAG
+#define PPP_MAXIDLEFLAG                 100
+#endif
+
+/*
+ * Packet sizes
+ *
+ * Note - lcp shouldn't be allowed to negotiate stuff outside these
+ *    limits.  See lcp.h in the pppd directory.
+ * (XXX - these constants should simply be shared by lcp.c instead
+ *    of living in lcp.h)
+ */
+#define PPP_MTU                         1500     /* Default MTU (size of Info field) */
+#ifndef PPP_MAXMTU
+/* #define PPP_MAXMTU  65535 - (PPP_HDRLEN + PPP_FCSLEN) */
+#define PPP_MAXMTU                      1500 /* Largest MTU we allow */
+#endif
+#define PPP_MINMTU                      64
+#define PPP_MRU                         1500     /* default MRU = max length of info field */
+#define PPP_MAXMRU                      1500     /* Largest MRU we allow */
+#ifndef PPP_DEFMRU
+#define PPP_DEFMRU                      296             /* Try for this */
+#endif
+#define PPP_MINMRU                      128             /* No MRUs below this */
+
+#ifndef MAXNAMELEN
+#define MAXNAMELEN                      256     /* max length of hostname or name for auth */
+#endif
+#ifndef MAXSECRETLEN
+#define MAXSECRETLEN                    256     /* max length of password or secret */
+#endif
+
+#endif /* PPP_SUPPORT */
+
+/*
+   --------------------------------------
+   ---------- Checksum options ----------
+   --------------------------------------
+*/
+/**
+ * CHECKSUM_GEN_IP==1: Generate checksums in software for outgoing IP packets.
+ */
+#ifndef CHECKSUM_GEN_IP
+#define CHECKSUM_GEN_IP                 1
+#endif
+ 
+/**
+ * CHECKSUM_GEN_UDP==1: Generate checksums in software for outgoing UDP packets.
+ */
+#ifndef CHECKSUM_GEN_UDP
+#define CHECKSUM_GEN_UDP                1
+#endif
+ 
+/**
+ * CHECKSUM_GEN_TCP==1: Generate checksums in software for outgoing TCP packets.
+ */
+#ifndef CHECKSUM_GEN_TCP
+#define CHECKSUM_GEN_TCP                1
+#endif
+ 
+/**
+ * CHECKSUM_CHECK_IP==1: Check checksums in software for incoming IP packets.
+ */
+#ifndef CHECKSUM_CHECK_IP
+#define CHECKSUM_CHECK_IP               1
+#endif
+ 
+/**
+ * CHECKSUM_CHECK_UDP==1: Check checksums in software for incoming UDP packets.
+ */
+#ifndef CHECKSUM_CHECK_UDP
+#define CHECKSUM_CHECK_UDP              1
+#endif
+
+/**
+ * CHECKSUM_CHECK_TCP==1: Check checksums in software for incoming TCP packets.
+ */
+#ifndef CHECKSUM_CHECK_TCP
+#define CHECKSUM_CHECK_TCP              1
+#endif
+
+/**
+ * LWIP_CHECKSUM_ON_COPY==1: Calculate checksum when copying data from
+ * application buffers to pbufs.
+ */
+#ifndef LWIP_CHECKSUM_ON_COPY
+#define LWIP_CHECKSUM_ON_COPY           0
+#endif
+
+/*
+   ---------------------------------------
+   ---------- Debugging options ----------
+   ---------------------------------------
+*/
+/**
+ * LWIP_DBG_MIN_LEVEL: After masking, the value of the debug is
+ * compared against this value. If it is smaller, then debugging
+ * messages are written.
+ */
+#ifndef LWIP_DBG_MIN_LEVEL
+#define LWIP_DBG_MIN_LEVEL              LWIP_DBG_LEVEL_ALL
+#endif
+
+/**
+ * LWIP_DBG_TYPES_ON: A mask that can be used to globally enable/disable
+ * debug messages of certain types.
+ */
+#ifndef LWIP_DBG_TYPES_ON
+#define LWIP_DBG_TYPES_ON               LWIP_DBG_ON
+#endif
+
+/**
+ * ETHARP_DEBUG: Enable debugging in etharp.c.
+ */
+#ifndef ETHARP_DEBUG
+#define ETHARP_DEBUG                    LWIP_DBG_OFF
+#endif
+
+/**
+ * NETIF_DEBUG: Enable debugging in netif.c.
+ */
+#ifndef NETIF_DEBUG
+#define NETIF_DEBUG                     LWIP_DBG_OFF
+#endif
+
+/**
+ * PBUF_DEBUG: Enable debugging in pbuf.c.
+ */
+#ifndef PBUF_DEBUG
+#define PBUF_DEBUG                      LWIP_DBG_OFF
+#endif
+
+/**
+ * API_LIB_DEBUG: Enable debugging in api_lib.c.
+ */
+#ifndef API_LIB_DEBUG
+#define API_LIB_DEBUG                   LWIP_DBG_OFF
+#endif
+
+/**
+ * API_MSG_DEBUG: Enable debugging in api_msg.c.
+ */
+#ifndef API_MSG_DEBUG
+#define API_MSG_DEBUG                   LWIP_DBG_OFF
+#endif
+
+/**
+ * SOCKETS_DEBUG: Enable debugging in sockets.c.
+ */
+#ifndef SOCKETS_DEBUG
+#define SOCKETS_DEBUG                   LWIP_DBG_OFF
+#endif
+
+/**
+ * ICMP_DEBUG: Enable debugging in icmp.c.
+ */
+#ifndef ICMP_DEBUG
+#define ICMP_DEBUG                      LWIP_DBG_OFF
+#endif
+
+/**
+ * IGMP_DEBUG: Enable debugging in igmp.c.
+ */
+#ifndef IGMP_DEBUG
+#define IGMP_DEBUG                      LWIP_DBG_OFF
+#endif
+
+/**
+ * INET_DEBUG: Enable debugging in inet.c.
+ */
+#ifndef INET_DEBUG
+#define INET_DEBUG                      LWIP_DBG_OFF
+#endif
+
+/**
+ * IP_DEBUG: Enable debugging for IP.
+ */
+#ifndef IP_DEBUG
+#define IP_DEBUG                        LWIP_DBG_OFF
+#endif
+
+/**
+ * IP_REASS_DEBUG: Enable debugging in ip_frag.c for both frag & reass.
+ */
+#ifndef IP_REASS_DEBUG
+#define IP_REASS_DEBUG                  LWIP_DBG_OFF
+#endif
+
+/**
+ * RAW_DEBUG: Enable debugging in raw.c.
+ */
+#ifndef RAW_DEBUG
+#define RAW_DEBUG                       LWIP_DBG_OFF
+#endif
+
+/**
+ * MEM_DEBUG: Enable debugging in mem.c.
+ */
+#ifndef MEM_DEBUG
+#define MEM_DEBUG                       LWIP_DBG_OFF
+#endif
+
+/**
+ * MEMP_DEBUG: Enable debugging in memp.c.
+ */
+#ifndef MEMP_DEBUG
+#define MEMP_DEBUG                      LWIP_DBG_OFF
+#endif
+
+/**
+ * SYS_DEBUG: Enable debugging in sys.c.
+ */
+#ifndef SYS_DEBUG
+#define SYS_DEBUG                       LWIP_DBG_OFF
+#endif
+
+/**
+ * TIMERS_DEBUG: Enable debugging in timers.c.
+ */
+#ifndef TIMERS_DEBUG
+#define TIMERS_DEBUG                    LWIP_DBG_OFF
+#endif
+
+/**
+ * TCP_DEBUG: Enable debugging for TCP.
+ */
+#ifndef TCP_DEBUG
+#define TCP_DEBUG                       LWIP_DBG_OFF
+#endif
+
+/**
+ * TCP_INPUT_DEBUG: Enable debugging in tcp_in.c for incoming debug.
+ */
+#ifndef TCP_INPUT_DEBUG
+#define TCP_INPUT_DEBUG                 LWIP_DBG_OFF
+#endif
+
+/**
+ * TCP_FR_DEBUG: Enable debugging in tcp_in.c for fast retransmit.
+ */
+#ifndef TCP_FR_DEBUG
+#define TCP_FR_DEBUG                    LWIP_DBG_OFF
+#endif
+
+/**
+ * TCP_RTO_DEBUG: Enable debugging in TCP for retransmit
+ * timeout.
+ */
+#ifndef TCP_RTO_DEBUG
+#define TCP_RTO_DEBUG                   LWIP_DBG_OFF
+#endif
+
+/**
+ * TCP_CWND_DEBUG: Enable debugging for TCP congestion window.
+ */
+#ifndef TCP_CWND_DEBUG
+#define TCP_CWND_DEBUG                  LWIP_DBG_OFF
+#endif
+
+/**
+ * TCP_WND_DEBUG: Enable debugging in tcp_in.c for window updating.
+ */
+#ifndef TCP_WND_DEBUG
+#define TCP_WND_DEBUG                   LWIP_DBG_OFF
+#endif
+
+/**
+ * TCP_OUTPUT_DEBUG: Enable debugging in tcp_out.c output functions.
+ */
+#ifndef TCP_OUTPUT_DEBUG
+#define TCP_OUTPUT_DEBUG                LWIP_DBG_OFF
+#endif
+
+/**
+ * TCP_RST_DEBUG: Enable debugging for TCP with the RST message.
+ */
+#ifndef TCP_RST_DEBUG
+#define TCP_RST_DEBUG                   LWIP_DBG_OFF
+#endif
+
+/**
+ * TCP_QLEN_DEBUG: Enable debugging for TCP queue lengths.
+ */
+#ifndef TCP_QLEN_DEBUG
+#define TCP_QLEN_DEBUG                  LWIP_DBG_OFF
+#endif
+
+/**
+ * UDP_DEBUG: Enable debugging in UDP.
+ */
+#ifndef UDP_DEBUG
+#define UDP_DEBUG                       LWIP_DBG_OFF
+#endif
+
+/**
+ * TCPIP_DEBUG: Enable debugging in tcpip.c.
+ */
+#ifndef TCPIP_DEBUG
+#define TCPIP_DEBUG                     LWIP_DBG_OFF
+#endif
+
+/**
+ * PPP_DEBUG: Enable debugging for PPP.
+ */
+#ifndef PPP_DEBUG
+#define PPP_DEBUG                       LWIP_DBG_OFF
+#endif
+
+/**
+ * SLIP_DEBUG: Enable debugging in slipif.c.
+ */
+#ifndef SLIP_DEBUG
+#define SLIP_DEBUG                      LWIP_DBG_OFF
+#endif
+
+/**
+ * DHCP_DEBUG: Enable debugging in dhcp.c.
+ */
+#ifndef DHCP_DEBUG
+#define DHCP_DEBUG                      LWIP_DBG_OFF
+#endif
+
+/**
+ * AUTOIP_DEBUG: Enable debugging in autoip.c.
+ */
+#ifndef AUTOIP_DEBUG
+#define AUTOIP_DEBUG                    LWIP_DBG_OFF
+#endif
+
+/**
+ * SNMP_MSG_DEBUG: Enable debugging for SNMP messages.
+ */
+#ifndef SNMP_MSG_DEBUG
+#define SNMP_MSG_DEBUG                  LWIP_DBG_OFF
+#endif
+
+/**
+ * SNMP_MIB_DEBUG: Enable debugging for SNMP MIBs.
+ */
+#ifndef SNMP_MIB_DEBUG
+#define SNMP_MIB_DEBUG                  LWIP_DBG_OFF
+#endif
+
+/**
+ * DNS_DEBUG: Enable debugging for DNS.
+ */
+#ifndef DNS_DEBUG
+#define DNS_DEBUG                       LWIP_DBG_OFF
+#endif
+
+#endif /* __LWIP_OPT_H__ */
diff --git a/core/lwip/src/include/lwip/pbuf.h b/core/lwip/src/include/lwip/pbuf.h
new file mode 100644
index 00000000..3b1d608b
--- /dev/null
+++ b/core/lwip/src/include/lwip/pbuf.h
@@ -0,0 +1,154 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#ifndef __LWIP_PBUF_H__
+#define __LWIP_PBUF_H__
+
+#include "lwip/opt.h"
+#include "lwip/err.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** Currently, the pbuf_custom code is only needed for one specific configuration
+ * of IP_FRAG */
+#define LWIP_SUPPORT_CUSTOM_PBUF (IP_FRAG && !IP_FRAG_USES_STATIC_BUF && !LWIP_NETIF_TX_SINGLE_PBUF)
+
+#define PBUF_TRANSPORT_HLEN 20
+#define PBUF_IP_HLEN        20
+
+typedef enum {
+  PBUF_TRANSPORT,
+  PBUF_IP,
+  PBUF_LINK,
+  PBUF_RAW
+} pbuf_layer;
+
+typedef enum {
+  PBUF_RAM, /* pbuf data is stored in RAM */
+  PBUF_ROM, /* pbuf data is stored in ROM */
+  PBUF_REF, /* pbuf comes from the pbuf pool */
+  PBUF_POOL /* pbuf payload refers to RAM */
+} pbuf_type;
+
+
+/** indicates this packet's data should be immediately passed to the application */
+#define PBUF_FLAG_PUSH      0x01U
+/** indicates this is a custom pbuf: pbuf_free and pbuf_header handle such a
+    a pbuf differently */
+#define PBUF_FLAG_IS_CUSTOM 0x02U
+/** indicates this pbuf is UDP multicast to be looped back */
+#define PBUF_FLAG_MCASTLOOP 0x04U
+
+struct pbuf {
+  /** next pbuf in singly linked pbuf chain */
+  struct pbuf *next;
+
+  /** pointer to the actual data in the buffer */
+  void *payload;
+
+  /**
+   * total length of this buffer and all next buffers in chain
+   * belonging to the same packet.
+   *
+   * For non-queue packet chains this is the invariant:
+   * p->tot_len == p->len + (p->next? p->next->tot_len: 0)
+   */
+  u16_t tot_len;
+
+  /** length of this buffer */
+  u16_t len;
+
+  /** pbuf_type as u8_t instead of enum to save space */
+  u8_t /*pbuf_type*/ type;
+
+  /** misc flags */
+  u8_t flags;
+
+  /**
+   * the reference count always equals the number of pointers
+   * that refer to this pbuf. This can be pointers from an application,
+   * the stack itself, or pbuf->next pointers from a chain.
+   */
+  u16_t ref;
+};
+
+#if LWIP_SUPPORT_CUSTOM_PBUF
+/** Prototype for a function to free a custom pbuf */
+typedef void (*pbuf_free_custom_fn)(struct pbuf *p);
+
+/** A custom pbuf: like a pbuf, but following a function pointer to free it. */
+struct pbuf_custom {
+  /** The actual pbuf */
+  struct pbuf pbuf;
+  /** This function is called when pbuf_free deallocates this pbuf(_custom) */
+  pbuf_free_custom_fn custom_free_function;
+};
+#endif /* LWIP_SUPPORT_CUSTOM_PBUF */
+
+/* Initializes the pbuf module. This call is empty for now, but may not be in future. */
+#define pbuf_init()
+
+struct pbuf *pbuf_alloc(pbuf_layer l, u16_t length, pbuf_type type);
+#if LWIP_SUPPORT_CUSTOM_PBUF
+struct pbuf *pbuf_alloced_custom(pbuf_layer l, u16_t length, pbuf_type type,
+                                 struct pbuf_custom *p, void *payload_mem,
+                                 u16_t payload_mem_len);
+#endif /* LWIP_SUPPORT_CUSTOM_PBUF */
+void pbuf_realloc(struct pbuf *p, u16_t size); 
+u8_t pbuf_header(struct pbuf *p, s16_t header_size);
+void pbuf_ref(struct pbuf *p);
+u8_t pbuf_free(struct pbuf *p);
+u8_t pbuf_clen(struct pbuf *p);  
+void pbuf_cat(struct pbuf *head, struct pbuf *tail);
+void pbuf_chain(struct pbuf *head, struct pbuf *tail);
+struct pbuf *pbuf_dechain(struct pbuf *p);
+err_t pbuf_copy(struct pbuf *p_to, struct pbuf *p_from);
+u16_t pbuf_copy_partial(struct pbuf *p, void *dataptr, u16_t len, u16_t offset);
+err_t pbuf_take(struct pbuf *buf, const void *dataptr, u16_t len);
+struct pbuf *pbuf_coalesce(struct pbuf *p, pbuf_layer layer);
+#if LWIP_CHECKSUM_ON_COPY
+err_t pbuf_fill_chksum(struct pbuf *p, u16_t start_offset, const void *dataptr,
+                       u16_t len, u16_t *chksum);
+#endif /* LWIP_CHECKSUM_ON_COPY */
+
+u8_t pbuf_get_at(struct pbuf* p, u16_t offset);
+u16_t pbuf_memcmp(struct pbuf* p, u16_t offset, const void* s2, u16_t n);
+u16_t pbuf_memfind(struct pbuf* p, const void* mem, u16_t mem_len, u16_t start_offset);
+u16_t pbuf_strstr(struct pbuf* p, const char* substr);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_PBUF_H__ */
diff --git a/core/lwip/src/include/lwip/raw.h b/core/lwip/src/include/lwip/raw.h
new file mode 100644
index 00000000..17d0a1c5
--- /dev/null
+++ b/core/lwip/src/include/lwip/raw.h
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_RAW_H__
+#define __LWIP_RAW_H__
+
+#include "lwip/opt.h"
+
+#if LWIP_RAW /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/pbuf.h"
+#include "lwip/def.h"
+#include "lwip/ip.h"
+#include "lwip/ip_addr.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct raw_pcb;
+
+/** Function prototype for raw pcb receive callback functions.
+ * @param arg user supplied argument (raw_pcb.recv_arg)
+ * @param pcb the raw_pcb which received data
+ * @param p the packet buffer that was received
+ * @param addr the remote IP address from which the packet was received
+ * @return 1 if the packet was 'eaten' (aka. deleted),
+ *         0 if the packet lives on
+ * If returning 1, the callback is responsible for freeing the pbuf
+ * if it's not used any more.
+ */
+typedef u8_t (*raw_recv_fn)(void *arg, struct raw_pcb *pcb, struct pbuf *p,
+    ip_addr_t *addr);
+
+struct raw_pcb {
+  /* Common members of all PCB types */
+  IP_PCB;
+
+  struct raw_pcb *next;
+
+  u8_t protocol;
+
+  /** receive callback function */
+  raw_recv_fn recv;
+  /* user-supplied argument for the recv callback */
+  void *recv_arg;
+};
+
+/* The following functions is the application layer interface to the
+   RAW code. */
+struct raw_pcb * raw_new        (u8_t proto);
+void             raw_remove     (struct raw_pcb *pcb);
+err_t            raw_bind       (struct raw_pcb *pcb, ip_addr_t *ipaddr);
+err_t            raw_connect    (struct raw_pcb *pcb, ip_addr_t *ipaddr);
+
+void             raw_recv       (struct raw_pcb *pcb, raw_recv_fn recv, void *recv_arg);
+err_t            raw_sendto     (struct raw_pcb *pcb, struct pbuf *p, ip_addr_t *ipaddr);
+err_t            raw_send       (struct raw_pcb *pcb, struct pbuf *p);
+
+/* The following functions are the lower layer interface to RAW. */
+u8_t             raw_input      (struct pbuf *p, struct netif *inp);
+#define raw_init() /* Compatibility define, not init needed. */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_RAW */
+
+#endif /* __LWIP_RAW_H__ */
diff --git a/core/lwip/src/include/lwip/sio.h b/core/lwip/src/include/lwip/sio.h
new file mode 100644
index 00000000..28ae2f22
--- /dev/null
+++ b/core/lwip/src/include/lwip/sio.h
@@ -0,0 +1,141 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ */
+
+/*
+ * This is the interface to the platform specific serial IO module
+ * It needs to be implemented by those platforms which need SLIP or PPP
+ */
+
+#ifndef __SIO_H__
+#define __SIO_H__
+
+#include "lwip/arch.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* If you want to define sio_fd_t elsewhere or differently,
+   define this in your cc.h file. */
+#ifndef __sio_fd_t_defined
+typedef void * sio_fd_t;
+#endif
+
+/* The following functions can be defined to something else in your cc.h file
+   or be implemented in your custom sio.c file. */
+
+#ifndef sio_open
+/**
+ * Opens a serial device for communication.
+ * 
+ * @param devnum device number
+ * @return handle to serial device if successful, NULL otherwise
+ */
+sio_fd_t sio_open(u8_t devnum);
+#endif
+
+#ifndef sio_send
+/**
+ * Sends a single character to the serial device.
+ * 
+ * @param c character to send
+ * @param fd serial device handle
+ * 
+ * @note This function will block until the character can be sent.
+ */
+void sio_send(u8_t c, sio_fd_t fd);
+#endif
+
+#ifndef sio_recv
+/**
+ * Receives a single character from the serial device.
+ * 
+ * @param fd serial device handle
+ * 
+ * @note This function will block until a character is received.
+ */
+u8_t sio_recv(sio_fd_t fd);
+#endif
+
+#ifndef sio_read
+/**
+ * Reads from the serial device.
+ * 
+ * @param fd serial device handle
+ * @param data pointer to data buffer for receiving
+ * @param len maximum length (in bytes) of data to receive
+ * @return number of bytes actually received - may be 0 if aborted by sio_read_abort
+ * 
+ * @note This function will block until data can be received. The blocking
+ * can be cancelled by calling sio_read_abort().
+ */
+u32_t sio_read(sio_fd_t fd, u8_t *data, u32_t len);
+#endif
+
+#ifndef sio_tryread
+/**
+ * Tries to read from the serial device. Same as sio_read but returns
+ * immediately if no data is available and never blocks.
+ * 
+ * @param fd serial device handle
+ * @param data pointer to data buffer for receiving
+ * @param len maximum length (in bytes) of data to receive
+ * @return number of bytes actually received
+ */
+u32_t sio_tryread(sio_fd_t fd, u8_t *data, u32_t len);
+#endif
+
+#ifndef sio_write
+/**
+ * Writes to the serial device.
+ * 
+ * @param fd serial device handle
+ * @param data pointer to data to send
+ * @param len length (in bytes) of data to send
+ * @return number of bytes actually sent
+ * 
+ * @note This function will block until all data can be sent.
+ */
+u32_t sio_write(sio_fd_t fd, u8_t *data, u32_t len);
+#endif
+
+#ifndef sio_read_abort
+/**
+ * Aborts a blocking sio_read() call.
+ * 
+ * @param fd serial device handle
+ */
+void sio_read_abort(sio_fd_t fd);
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __SIO_H__ */
diff --git a/core/lwip/src/include/lwip/snmp.h b/core/lwip/src/include/lwip/snmp.h
new file mode 100644
index 00000000..2ed043dd
--- /dev/null
+++ b/core/lwip/src/include/lwip/snmp.h
@@ -0,0 +1,367 @@
+/*
+ * Copyright (c) 2001, 2002 Leon Woestenberg <leon.woestenberg@axon.tv>
+ * Copyright (c) 2001, 2002 Axon Digital Design B.V., The Netherlands.
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Leon Woestenberg <leon.woestenberg@axon.tv>
+ *
+ */
+#ifndef __LWIP_SNMP_H__
+#define __LWIP_SNMP_H__
+
+#include "lwip/opt.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "lwip/ip_addr.h"
+
+struct udp_pcb;
+struct netif;
+
+/**
+ * @see RFC1213, "MIB-II, 6. Definitions"
+ */
+enum snmp_ifType {
+  snmp_ifType_other=1,                /* none of the following */
+  snmp_ifType_regular1822,
+  snmp_ifType_hdh1822,
+  snmp_ifType_ddn_x25,
+  snmp_ifType_rfc877_x25,
+  snmp_ifType_ethernet_csmacd,
+  snmp_ifType_iso88023_csmacd,
+  snmp_ifType_iso88024_tokenBus,
+  snmp_ifType_iso88025_tokenRing,
+  snmp_ifType_iso88026_man,
+  snmp_ifType_starLan,
+  snmp_ifType_proteon_10Mbit,
+  snmp_ifType_proteon_80Mbit,
+  snmp_ifType_hyperchannel,
+  snmp_ifType_fddi,
+  snmp_ifType_lapb,
+  snmp_ifType_sdlc,
+  snmp_ifType_ds1,                    /* T-1 */
+  snmp_ifType_e1,                     /* european equiv. of T-1 */
+  snmp_ifType_basicISDN,
+  snmp_ifType_primaryISDN,            /* proprietary serial */
+  snmp_ifType_propPointToPointSerial,
+  snmp_ifType_ppp,
+  snmp_ifType_softwareLoopback,
+  snmp_ifType_eon,                    /* CLNP over IP [11] */
+  snmp_ifType_ethernet_3Mbit,
+  snmp_ifType_nsip,                   /* XNS over IP */
+  snmp_ifType_slip,                   /* generic SLIP */
+  snmp_ifType_ultra,                  /* ULTRA technologies */
+  snmp_ifType_ds3,                    /* T-3 */
+  snmp_ifType_sip,                    /* SMDS */
+  snmp_ifType_frame_relay
+};
+
+#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
+
+/** SNMP "sysuptime" Interval */
+#define SNMP_SYSUPTIME_INTERVAL 10
+
+/** fixed maximum length for object identifier type */
+#define LWIP_SNMP_OBJ_ID_LEN 32
+
+/** internal object identifier representation */
+struct snmp_obj_id
+{
+  u8_t len;
+  s32_t id[LWIP_SNMP_OBJ_ID_LEN];
+};
+
+/* system */
+void snmp_set_sysdesr(u8_t* str, u8_t* len);
+void snmp_set_sysobjid(struct snmp_obj_id *oid);
+void snmp_get_sysobjid_ptr(struct snmp_obj_id **oid);
+void snmp_inc_sysuptime(void);
+void snmp_add_sysuptime(u32_t value);
+void snmp_get_sysuptime(u32_t *value);
+void snmp_set_syscontact(u8_t *ocstr, u8_t *ocstrlen);
+void snmp_set_sysname(u8_t *ocstr, u8_t *ocstrlen);
+void snmp_set_syslocation(u8_t *ocstr, u8_t *ocstrlen);
+
+/* network interface */
+void snmp_add_ifinoctets(struct netif *ni, u32_t value); 
+void snmp_inc_ifinucastpkts(struct netif *ni);
+void snmp_inc_ifinnucastpkts(struct netif *ni);
+void snmp_inc_ifindiscards(struct netif *ni);
+void snmp_add_ifoutoctets(struct netif *ni, u32_t value);
+void snmp_inc_ifoutucastpkts(struct netif *ni);
+void snmp_inc_ifoutnucastpkts(struct netif *ni);
+void snmp_inc_ifoutdiscards(struct netif *ni);
+void snmp_inc_iflist(void);
+void snmp_dec_iflist(void);
+
+/* ARP (for atTable and ipNetToMediaTable) */
+void snmp_insert_arpidx_tree(struct netif *ni, ip_addr_t *ip);
+void snmp_delete_arpidx_tree(struct netif *ni, ip_addr_t *ip);
+
+/* IP */
+void snmp_inc_ipinreceives(void);
+void snmp_inc_ipinhdrerrors(void);
+void snmp_inc_ipinaddrerrors(void);
+void snmp_inc_ipforwdatagrams(void);
+void snmp_inc_ipinunknownprotos(void);
+void snmp_inc_ipindiscards(void);
+void snmp_inc_ipindelivers(void);
+void snmp_inc_ipoutrequests(void);
+void snmp_inc_ipoutdiscards(void);
+void snmp_inc_ipoutnoroutes(void);
+void snmp_inc_ipreasmreqds(void);
+void snmp_inc_ipreasmoks(void);
+void snmp_inc_ipreasmfails(void);
+void snmp_inc_ipfragoks(void);
+void snmp_inc_ipfragfails(void);
+void snmp_inc_ipfragcreates(void);
+void snmp_inc_iproutingdiscards(void);
+void snmp_insert_ipaddridx_tree(struct netif *ni);
+void snmp_delete_ipaddridx_tree(struct netif *ni);
+void snmp_insert_iprteidx_tree(u8_t dflt, struct netif *ni);
+void snmp_delete_iprteidx_tree(u8_t dflt, struct netif *ni);
+
+/* ICMP */
+void snmp_inc_icmpinmsgs(void);
+void snmp_inc_icmpinerrors(void);
+void snmp_inc_icmpindestunreachs(void);
+void snmp_inc_icmpintimeexcds(void);
+void snmp_inc_icmpinparmprobs(void);
+void snmp_inc_icmpinsrcquenchs(void);
+void snmp_inc_icmpinredirects(void);
+void snmp_inc_icmpinechos(void);
+void snmp_inc_icmpinechoreps(void);
+void snmp_inc_icmpintimestamps(void);
+void snmp_inc_icmpintimestampreps(void);
+void snmp_inc_icmpinaddrmasks(void);
+void snmp_inc_icmpinaddrmaskreps(void);
+void snmp_inc_icmpoutmsgs(void);
+void snmp_inc_icmpouterrors(void);
+void snmp_inc_icmpoutdestunreachs(void);
+void snmp_inc_icmpouttimeexcds(void);
+void snmp_inc_icmpoutparmprobs(void);
+void snmp_inc_icmpoutsrcquenchs(void);
+void snmp_inc_icmpoutredirects(void); 
+void snmp_inc_icmpoutechos(void);
+void snmp_inc_icmpoutechoreps(void);
+void snmp_inc_icmpouttimestamps(void);
+void snmp_inc_icmpouttimestampreps(void);
+void snmp_inc_icmpoutaddrmasks(void);
+void snmp_inc_icmpoutaddrmaskreps(void);
+
+/* TCP */
+void snmp_inc_tcpactiveopens(void);
+void snmp_inc_tcppassiveopens(void);
+void snmp_inc_tcpattemptfails(void);
+void snmp_inc_tcpestabresets(void);
+void snmp_inc_tcpinsegs(void);
+void snmp_inc_tcpoutsegs(void);
+void snmp_inc_tcpretranssegs(void);
+void snmp_inc_tcpinerrs(void);
+void snmp_inc_tcpoutrsts(void);
+
+/* UDP */
+void snmp_inc_udpindatagrams(void);
+void snmp_inc_udpnoports(void);
+void snmp_inc_udpinerrors(void);
+void snmp_inc_udpoutdatagrams(void);
+void snmp_insert_udpidx_tree(struct udp_pcb *pcb);
+void snmp_delete_udpidx_tree(struct udp_pcb *pcb);
+
+/* SNMP */
+void snmp_inc_snmpinpkts(void);
+void snmp_inc_snmpoutpkts(void);
+void snmp_inc_snmpinbadversions(void);
+void snmp_inc_snmpinbadcommunitynames(void);
+void snmp_inc_snmpinbadcommunityuses(void);
+void snmp_inc_snmpinasnparseerrs(void);
+void snmp_inc_snmpintoobigs(void);
+void snmp_inc_snmpinnosuchnames(void);
+void snmp_inc_snmpinbadvalues(void);
+void snmp_inc_snmpinreadonlys(void);
+void snmp_inc_snmpingenerrs(void);
+void snmp_add_snmpintotalreqvars(u8_t value);
+void snmp_add_snmpintotalsetvars(u8_t value);
+void snmp_inc_snmpingetrequests(void);
+void snmp_inc_snmpingetnexts(void);
+void snmp_inc_snmpinsetrequests(void);
+void snmp_inc_snmpingetresponses(void);
+void snmp_inc_snmpintraps(void);
+void snmp_inc_snmpouttoobigs(void);
+void snmp_inc_snmpoutnosuchnames(void);
+void snmp_inc_snmpoutbadvalues(void);
+void snmp_inc_snmpoutgenerrs(void);
+void snmp_inc_snmpoutgetrequests(void);
+void snmp_inc_snmpoutgetnexts(void);
+void snmp_inc_snmpoutsetrequests(void);
+void snmp_inc_snmpoutgetresponses(void);
+void snmp_inc_snmpouttraps(void);
+void snmp_get_snmpgrpid_ptr(struct snmp_obj_id **oid);
+void snmp_set_snmpenableauthentraps(u8_t *value);
+void snmp_get_snmpenableauthentraps(u8_t *value);
+
+/* LWIP_SNMP support not available */
+/* define everything to be empty */
+#else
+
+/* system */
+#define snmp_set_sysdesr(str, len)
+#define snmp_set_sysobjid(oid);
+#define snmp_get_sysobjid_ptr(oid)
+#define snmp_inc_sysuptime()
+#define snmp_add_sysuptime(value)
+#define snmp_get_sysuptime(value)
+#define snmp_set_syscontact(ocstr, ocstrlen);
+#define snmp_set_sysname(ocstr, ocstrlen);
+#define snmp_set_syslocation(ocstr, ocstrlen);
+
+/* network interface */
+#define snmp_add_ifinoctets(ni,value) 
+#define snmp_inc_ifinucastpkts(ni)
+#define snmp_inc_ifinnucastpkts(ni)
+#define snmp_inc_ifindiscards(ni)
+#define snmp_add_ifoutoctets(ni,value)
+#define snmp_inc_ifoutucastpkts(ni)
+#define snmp_inc_ifoutnucastpkts(ni)
+#define snmp_inc_ifoutdiscards(ni)
+#define snmp_inc_iflist()
+#define snmp_dec_iflist()
+
+/* ARP */
+#define snmp_insert_arpidx_tree(ni,ip)
+#define snmp_delete_arpidx_tree(ni,ip)
+
+/* IP */
+#define snmp_inc_ipinreceives()
+#define snmp_inc_ipinhdrerrors()
+#define snmp_inc_ipinaddrerrors()
+#define snmp_inc_ipforwdatagrams()
+#define snmp_inc_ipinunknownprotos()
+#define snmp_inc_ipindiscards()
+#define snmp_inc_ipindelivers()
+#define snmp_inc_ipoutrequests()
+#define snmp_inc_ipoutdiscards()
+#define snmp_inc_ipoutnoroutes()
+#define snmp_inc_ipreasmreqds()
+#define snmp_inc_ipreasmoks()
+#define snmp_inc_ipreasmfails()
+#define snmp_inc_ipfragoks()
+#define snmp_inc_ipfragfails()
+#define snmp_inc_ipfragcreates()
+#define snmp_inc_iproutingdiscards()
+#define snmp_insert_ipaddridx_tree(ni)
+#define snmp_delete_ipaddridx_tree(ni)
+#define snmp_insert_iprteidx_tree(dflt, ni)
+#define snmp_delete_iprteidx_tree(dflt, ni)
+
+/* ICMP */
+#define snmp_inc_icmpinmsgs()
+#define snmp_inc_icmpinerrors() 
+#define snmp_inc_icmpindestunreachs() 
+#define snmp_inc_icmpintimeexcds()
+#define snmp_inc_icmpinparmprobs() 
+#define snmp_inc_icmpinsrcquenchs() 
+#define snmp_inc_icmpinredirects() 
+#define snmp_inc_icmpinechos() 
+#define snmp_inc_icmpinechoreps()
+#define snmp_inc_icmpintimestamps() 
+#define snmp_inc_icmpintimestampreps()
+#define snmp_inc_icmpinaddrmasks()
+#define snmp_inc_icmpinaddrmaskreps()
+#define snmp_inc_icmpoutmsgs()
+#define snmp_inc_icmpouterrors()
+#define snmp_inc_icmpoutdestunreachs() 
+#define snmp_inc_icmpouttimeexcds() 
+#define snmp_inc_icmpoutparmprobs()
+#define snmp_inc_icmpoutsrcquenchs()
+#define snmp_inc_icmpoutredirects() 
+#define snmp_inc_icmpoutechos() 
+#define snmp_inc_icmpoutechoreps()
+#define snmp_inc_icmpouttimestamps()
+#define snmp_inc_icmpouttimestampreps()
+#define snmp_inc_icmpoutaddrmasks()
+#define snmp_inc_icmpoutaddrmaskreps()
+/* TCP */
+#define snmp_inc_tcpactiveopens()
+#define snmp_inc_tcppassiveopens()
+#define snmp_inc_tcpattemptfails()
+#define snmp_inc_tcpestabresets()
+#define snmp_inc_tcpinsegs()
+#define snmp_inc_tcpoutsegs()
+#define snmp_inc_tcpretranssegs()
+#define snmp_inc_tcpinerrs()
+#define snmp_inc_tcpoutrsts()
+
+/* UDP */
+#define snmp_inc_udpindatagrams()
+#define snmp_inc_udpnoports()
+#define snmp_inc_udpinerrors()
+#define snmp_inc_udpoutdatagrams()
+#define snmp_insert_udpidx_tree(pcb)
+#define snmp_delete_udpidx_tree(pcb)
+
+/* SNMP */
+#define snmp_inc_snmpinpkts()
+#define snmp_inc_snmpoutpkts()
+#define snmp_inc_snmpinbadversions()
+#define snmp_inc_snmpinbadcommunitynames()
+#define snmp_inc_snmpinbadcommunityuses()
+#define snmp_inc_snmpinasnparseerrs()
+#define snmp_inc_snmpintoobigs()
+#define snmp_inc_snmpinnosuchnames()
+#define snmp_inc_snmpinbadvalues()
+#define snmp_inc_snmpinreadonlys()
+#define snmp_inc_snmpingenerrs()
+#define snmp_add_snmpintotalreqvars(value)
+#define snmp_add_snmpintotalsetvars(value)
+#define snmp_inc_snmpingetrequests()
+#define snmp_inc_snmpingetnexts()
+#define snmp_inc_snmpinsetrequests()
+#define snmp_inc_snmpingetresponses()
+#define snmp_inc_snmpintraps()
+#define snmp_inc_snmpouttoobigs()
+#define snmp_inc_snmpoutnosuchnames()
+#define snmp_inc_snmpoutbadvalues()
+#define snmp_inc_snmpoutgenerrs()
+#define snmp_inc_snmpoutgetrequests()
+#define snmp_inc_snmpoutgetnexts()
+#define snmp_inc_snmpoutsetrequests()
+#define snmp_inc_snmpoutgetresponses()
+#define snmp_inc_snmpouttraps()
+#define snmp_get_snmpgrpid_ptr(oid)
+#define snmp_set_snmpenableauthentraps(value)
+#define snmp_get_snmpenableauthentraps(value)
+
+#endif /* LWIP_SNMP */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_SNMP_H__ */
diff --git a/core/lwip/src/include/lwip/snmp_asn1.h b/core/lwip/src/include/lwip/snmp_asn1.h
new file mode 100644
index 00000000..605fa3f1
--- /dev/null
+++ b/core/lwip/src/include/lwip/snmp_asn1.h
@@ -0,0 +1,101 @@
+/**
+ * @file
+ * Abstract Syntax Notation One (ISO 8824, 8825) codec.
+ */
+ 
+/*
+ * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * Author: Christiaan Simons <christiaan.simons@axon.tv>
+ */
+
+#ifndef __LWIP_SNMP_ASN1_H__
+#define __LWIP_SNMP_ASN1_H__
+
+#include "lwip/opt.h"
+#include "lwip/err.h"
+#include "lwip/pbuf.h"
+#include "lwip/snmp.h"
+
+#if LWIP_SNMP
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define SNMP_ASN1_UNIV   (0)    /* (!0x80 | !0x40) */
+#define SNMP_ASN1_APPLIC (0x40) /* (!0x80 |  0x40) */
+#define SNMP_ASN1_CONTXT (0x80) /* ( 0x80 | !0x40) */
+
+#define SNMP_ASN1_CONSTR (0x20) /* ( 0x20) */
+#define SNMP_ASN1_PRIMIT (0)    /* (!0x20) */
+
+/* universal tags */
+#define SNMP_ASN1_INTEG  2
+#define SNMP_ASN1_OC_STR 4
+#define SNMP_ASN1_NUL    5
+#define SNMP_ASN1_OBJ_ID 6
+#define SNMP_ASN1_SEQ    16
+
+/* application specific (SNMP) tags */
+#define SNMP_ASN1_IPADDR 0    /* octet string size(4) */
+#define SNMP_ASN1_COUNTER 1   /* u32_t */
+#define SNMP_ASN1_GAUGE 2     /* u32_t */
+#define SNMP_ASN1_TIMETICKS 3 /* u32_t */
+#define SNMP_ASN1_OPAQUE 4    /* octet string */
+
+/* context specific (SNMP) tags */
+#define SNMP_ASN1_PDU_GET_REQ 0
+#define SNMP_ASN1_PDU_GET_NEXT_REQ 1
+#define SNMP_ASN1_PDU_GET_RESP 2
+#define SNMP_ASN1_PDU_SET_REQ 3
+#define SNMP_ASN1_PDU_TRAP 4
+
+err_t snmp_asn1_dec_type(struct pbuf *p, u16_t ofs, u8_t *type);
+err_t snmp_asn1_dec_length(struct pbuf *p, u16_t ofs, u8_t *octets_used, u16_t *length);
+err_t snmp_asn1_dec_u32t(struct pbuf *p, u16_t ofs, u16_t len, u32_t *value);
+err_t snmp_asn1_dec_s32t(struct pbuf *p, u16_t ofs, u16_t len, s32_t *value);
+err_t snmp_asn1_dec_oid(struct pbuf *p, u16_t ofs, u16_t len, struct snmp_obj_id *oid);
+err_t snmp_asn1_dec_raw(struct pbuf *p, u16_t ofs, u16_t len, u16_t raw_len, u8_t *raw);
+
+void snmp_asn1_enc_length_cnt(u16_t length, u8_t *octets_needed);
+void snmp_asn1_enc_u32t_cnt(u32_t value, u16_t *octets_needed);
+void snmp_asn1_enc_s32t_cnt(s32_t value, u16_t *octets_needed);
+void snmp_asn1_enc_oid_cnt(u8_t ident_len, s32_t *ident, u16_t *octets_needed);
+err_t snmp_asn1_enc_type(struct pbuf *p, u16_t ofs, u8_t type);
+err_t snmp_asn1_enc_length(struct pbuf *p, u16_t ofs, u16_t length);
+err_t snmp_asn1_enc_u32t(struct pbuf *p, u16_t ofs, u16_t octets_needed, u32_t value);
+err_t snmp_asn1_enc_s32t(struct pbuf *p, u16_t ofs, u16_t octets_needed, s32_t value);
+err_t snmp_asn1_enc_oid(struct pbuf *p, u16_t ofs, u8_t ident_len, s32_t *ident);
+err_t snmp_asn1_enc_raw(struct pbuf *p, u16_t ofs, u16_t raw_len, u8_t *raw);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_SNMP */
+
+#endif /* __LWIP_SNMP_ASN1_H__ */
diff --git a/core/lwip/src/include/lwip/snmp_msg.h b/core/lwip/src/include/lwip/snmp_msg.h
new file mode 100644
index 00000000..1183e3a9
--- /dev/null
+++ b/core/lwip/src/include/lwip/snmp_msg.h
@@ -0,0 +1,315 @@
+/**
+ * @file
+ * SNMP Agent message handling structures.
+ */
+
+/*
+ * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * Author: Christiaan Simons <christiaan.simons@axon.tv>
+ */
+
+#ifndef __LWIP_SNMP_MSG_H__
+#define __LWIP_SNMP_MSG_H__
+
+#include "lwip/opt.h"
+#include "lwip/snmp.h"
+#include "lwip/snmp_structs.h"
+#include "lwip/ip_addr.h"
+#include "lwip/err.h"
+
+#if LWIP_SNMP
+
+#if SNMP_PRIVATE_MIB
+/* When using a private MIB, you have to create a file 'private_mib.h' that contains
+ * a 'struct mib_array_node mib_private' which contains your MIB. */
+#include "private_mib.h"
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* The listen port of the SNMP agent. Clients have to make their requests to
+   this port. Most standard clients won't work if you change this! */
+#ifndef SNMP_IN_PORT
+#define SNMP_IN_PORT 161
+#endif
+/* The remote port the SNMP agent sends traps to. Most standard trap sinks won't
+   work if you change this! */
+#ifndef SNMP_TRAP_PORT
+#define SNMP_TRAP_PORT 162
+#endif
+
+#define SNMP_ES_NOERROR 0
+#define SNMP_ES_TOOBIG 1
+#define SNMP_ES_NOSUCHNAME 2
+#define SNMP_ES_BADVALUE 3
+#define SNMP_ES_READONLY 4
+#define SNMP_ES_GENERROR 5
+
+#define SNMP_GENTRAP_COLDSTART 0
+#define SNMP_GENTRAP_WARMSTART 1
+#define SNMP_GENTRAP_AUTHFAIL 4
+#define SNMP_GENTRAP_ENTERPRISESPC 6
+
+struct snmp_varbind
+{
+  /* next pointer, NULL for last in list */
+  struct snmp_varbind *next;
+  /* previous pointer, NULL for first in list */
+  struct snmp_varbind *prev;
+
+  /* object identifier length (in s32_t) */
+  u8_t ident_len;
+  /* object identifier array */
+  s32_t *ident;
+
+  /* object value ASN1 type */
+  u8_t value_type;
+  /* object value length (in u8_t) */
+  u8_t value_len;
+  /* object value */
+  void *value;
+
+  /* encoding varbind seq length length */
+  u8_t seqlenlen;
+  /* encoding object identifier length length */
+  u8_t olenlen;
+  /* encoding object value length length */
+  u8_t vlenlen;
+  /* encoding varbind seq length */
+  u16_t seqlen;
+  /* encoding object identifier length */
+  u16_t olen;
+  /* encoding object value length */
+  u16_t vlen;
+};
+
+struct snmp_varbind_root
+{
+  struct snmp_varbind *head;
+  struct snmp_varbind *tail;
+  /* number of variable bindings in list */
+  u8_t count;
+  /* encoding varbind-list seq length length */
+  u8_t seqlenlen;
+  /* encoding varbind-list seq length */
+  u16_t seqlen;
+};
+
+/** output response message header length fields */
+struct snmp_resp_header_lengths
+{
+  /* encoding error-index length length */
+  u8_t erridxlenlen;
+  /* encoding error-status length length */
+  u8_t errstatlenlen;
+  /* encoding request id length length */
+  u8_t ridlenlen;
+  /* encoding pdu length length */
+  u8_t pdulenlen;
+  /* encoding community length length */
+  u8_t comlenlen;
+  /* encoding version length length */
+  u8_t verlenlen;
+  /* encoding sequence length length */
+  u8_t seqlenlen;
+
+  /* encoding error-index length */
+  u16_t erridxlen;
+  /* encoding error-status length */
+  u16_t errstatlen;
+  /* encoding request id length */
+  u16_t ridlen;
+  /* encoding pdu length */
+  u16_t pdulen;
+  /* encoding community length */
+  u16_t comlen;
+  /* encoding version length */
+  u16_t verlen;
+  /* encoding sequence length */
+  u16_t seqlen;
+};
+
+/** output response message header length fields */
+struct snmp_trap_header_lengths
+{
+  /* encoding timestamp length length */
+  u8_t tslenlen;
+  /* encoding specific-trap length length */
+  u8_t strplenlen;
+  /* encoding generic-trap length length */
+  u8_t gtrplenlen;
+  /* encoding agent-addr length length */
+  u8_t aaddrlenlen;
+  /* encoding enterprise-id length length */
+  u8_t eidlenlen;
+  /* encoding pdu length length */
+  u8_t pdulenlen;
+  /* encoding community length length */
+  u8_t comlenlen;
+  /* encoding version length length */
+  u8_t verlenlen;
+  /* encoding sequence length length */
+  u8_t seqlenlen;
+
+  /* encoding timestamp length */
+  u16_t tslen;
+  /* encoding specific-trap length */
+  u16_t strplen;
+  /* encoding generic-trap length */
+  u16_t gtrplen;
+  /* encoding agent-addr length */
+  u16_t aaddrlen;
+  /* encoding enterprise-id length */
+  u16_t eidlen;
+  /* encoding pdu length */
+  u16_t pdulen;
+  /* encoding community length */
+  u16_t comlen;
+  /* encoding version length */
+  u16_t verlen;
+  /* encoding sequence length */
+  u16_t seqlen;
+};
+
+/* Accepting new SNMP messages. */
+#define SNMP_MSG_EMPTY                 0
+/* Search for matching object for variable binding. */
+#define SNMP_MSG_SEARCH_OBJ            1
+/* Perform SNMP operation on in-memory object.
+   Pass-through states, for symmetry only. */
+#define SNMP_MSG_INTERNAL_GET_OBJDEF   2
+#define SNMP_MSG_INTERNAL_GET_VALUE    3
+#define SNMP_MSG_INTERNAL_SET_TEST     4
+#define SNMP_MSG_INTERNAL_GET_OBJDEF_S 5
+#define SNMP_MSG_INTERNAL_SET_VALUE    6
+/* Perform SNMP operation on object located externally.
+   In theory this could be used for building a proxy agent.
+   Practical use is for an enterprise spc. app. gateway. */
+#define SNMP_MSG_EXTERNAL_GET_OBJDEF   7
+#define SNMP_MSG_EXTERNAL_GET_VALUE    8
+#define SNMP_MSG_EXTERNAL_SET_TEST     9
+#define SNMP_MSG_EXTERNAL_GET_OBJDEF_S 10
+#define SNMP_MSG_EXTERNAL_SET_VALUE    11
+
+#define SNMP_COMMUNITY_STR_LEN 64
+struct snmp_msg_pstat
+{
+  /* lwIP local port (161) binding */
+  struct udp_pcb *pcb;
+  /* source IP address */
+  ip_addr_t sip;
+  /* source UDP port */
+  u16_t sp;
+  /* request type */
+  u8_t rt;
+  /* request ID */
+  s32_t rid;
+  /* error status */
+  s32_t error_status;
+  /* error index */
+  s32_t error_index;
+  /* community name (zero terminated) */
+  u8_t community[SNMP_COMMUNITY_STR_LEN + 1];
+  /* community string length (exclusive zero term) */
+  u8_t com_strlen;
+  /* one out of MSG_EMPTY, MSG_DEMUX, MSG_INTERNAL, MSG_EXTERNAL_x */
+  u8_t state;
+  /* saved arguments for MSG_EXTERNAL_x */
+  struct mib_external_node *ext_mib_node;
+  struct snmp_name_ptr ext_name_ptr;
+  struct obj_def ext_object_def;
+  struct snmp_obj_id ext_oid;
+  /* index into input variable binding list */
+  u8_t vb_idx;
+  /* ptr into input variable binding list */
+  struct snmp_varbind *vb_ptr;
+  /* list of variable bindings from input */
+  struct snmp_varbind_root invb;
+  /* list of variable bindings to output */
+  struct snmp_varbind_root outvb;
+  /* output response lengths used in ASN encoding */
+  struct snmp_resp_header_lengths rhl;
+};
+
+struct snmp_msg_trap
+{
+  /* lwIP local port (161) binding */
+  struct udp_pcb *pcb;
+  /* destination IP address in network order */
+  ip_addr_t dip;
+
+  /* source enterprise ID (sysObjectID) */
+  struct snmp_obj_id *enterprise;
+  /* source IP address, raw network order format */
+  u8_t sip_raw[4];
+  /* generic trap code */
+  u32_t gen_trap;
+  /* specific trap code */
+  u32_t spc_trap;
+  /* timestamp */
+  u32_t ts;
+  /* list of variable bindings to output */
+  struct snmp_varbind_root outvb;
+  /* output trap lengths used in ASN encoding */
+  struct snmp_trap_header_lengths thl;
+};
+
+/** Agent Version constant, 0 = v1 oddity */
+extern const s32_t snmp_version;
+/** Agent default "public" community string */
+extern const char snmp_publiccommunity[7];
+
+extern struct snmp_msg_trap trap_msg;
+
+/** Agent setup, start listening to port 161. */
+void snmp_init(void);
+void snmp_trap_dst_enable(u8_t dst_idx, u8_t enable);
+void snmp_trap_dst_ip_set(u8_t dst_idx, ip_addr_t *dst);
+
+/** Varbind-list functions. */
+struct snmp_varbind* snmp_varbind_alloc(struct snmp_obj_id *oid, u8_t type, u8_t len);
+void snmp_varbind_free(struct snmp_varbind *vb);
+void snmp_varbind_list_free(struct snmp_varbind_root *root);
+void snmp_varbind_tail_add(struct snmp_varbind_root *root, struct snmp_varbind *vb);
+struct snmp_varbind* snmp_varbind_tail_remove(struct snmp_varbind_root *root);
+
+/** Handle an internal (recv) or external (private response) event. */
+void snmp_msg_event(u8_t request_id);
+err_t snmp_send_response(struct snmp_msg_pstat *m_stat);
+err_t snmp_send_trap(s8_t generic_trap, struct snmp_obj_id *eoid, s32_t specific_trap);
+void snmp_coldstart_trap(void);
+void snmp_authfail_trap(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_SNMP */
+
+#endif /* __LWIP_SNMP_MSG_H__ */
diff --git a/core/lwip/src/include/lwip/snmp_structs.h b/core/lwip/src/include/lwip/snmp_structs.h
new file mode 100644
index 00000000..0d3b46a9
--- /dev/null
+++ b/core/lwip/src/include/lwip/snmp_structs.h
@@ -0,0 +1,268 @@
+/**
+ * @file
+ * Generic MIB tree structures.
+ *
+ * @todo namespace prefixes
+ */
+
+/*
+ * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * Author: Christiaan Simons <christiaan.simons@axon.tv>
+ */
+
+#ifndef __LWIP_SNMP_STRUCTS_H__
+#define __LWIP_SNMP_STRUCTS_H__
+
+#include "lwip/opt.h"
+
+#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/snmp.h"
+
+#if SNMP_PRIVATE_MIB
+/* When using a private MIB, you have to create a file 'private_mib.h' that contains
+ * a 'struct mib_array_node mib_private' which contains your MIB. */
+#include "private_mib.h"
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* MIB object instance */
+#define MIB_OBJECT_NONE 0 
+#define MIB_OBJECT_SCALAR 1
+#define MIB_OBJECT_TAB 2
+
+/* MIB access types */
+#define MIB_ACCESS_READ   1
+#define MIB_ACCESS_WRITE  2
+
+/* MIB object access */
+#define MIB_OBJECT_READ_ONLY      MIB_ACCESS_READ
+#define MIB_OBJECT_READ_WRITE     (MIB_ACCESS_READ | MIB_ACCESS_WRITE)
+#define MIB_OBJECT_WRITE_ONLY     MIB_ACCESS_WRITE
+#define MIB_OBJECT_NOT_ACCESSIBLE 0
+
+/** object definition returned by (get_object_def)() */
+struct obj_def
+{
+  /* MIB_OBJECT_NONE (0), MIB_OBJECT_SCALAR (1), MIB_OBJECT_TAB (2) */
+  u8_t instance;
+  /* 0 read-only, 1 read-write, 2 write-only, 3 not-accessible */
+  u8_t access;
+  /* ASN type for this object */
+  u8_t asn_type;
+  /* value length (host length) */
+  u16_t v_len;
+  /* length of instance part of supplied object identifier */
+  u8_t  id_inst_len;
+  /* instance part of supplied object identifier */
+  s32_t *id_inst_ptr;
+};
+
+struct snmp_name_ptr
+{
+  u8_t ident_len;
+  s32_t *ident;
+};
+
+/** MIB const scalar (.0) node */
+#define MIB_NODE_SC 0x01
+/** MIB const array node */
+#define MIB_NODE_AR 0x02
+/** MIB array node (mem_malloced from RAM) */
+#define MIB_NODE_RA 0x03
+/** MIB list root node (mem_malloced from RAM) */
+#define MIB_NODE_LR 0x04
+/** MIB node for external objects */
+#define MIB_NODE_EX 0x05
+
+/** node "base class" layout, the mandatory fields for a node  */
+struct mib_node
+{
+  /** returns struct obj_def for the given object identifier */
+  void (*get_object_def)(u8_t ident_len, s32_t *ident, struct obj_def *od);
+  /** returns object value for the given object identifier,
+     @note the caller must allocate at least len bytes for the value */
+  void (*get_value)(struct obj_def *od, u16_t len, void *value);
+  /** tests length and/or range BEFORE setting */
+  u8_t (*set_test)(struct obj_def *od, u16_t len, void *value);
+  /** sets object value, only to be called when set_test()  */
+  void (*set_value)(struct obj_def *od, u16_t len, void *value);  
+  /** One out of MIB_NODE_AR, MIB_NODE_LR or MIB_NODE_EX */
+  u8_t node_type;
+  /* array or max list length */
+  u16_t maxlength;
+};
+
+/** derived node for scalars .0 index */
+typedef struct mib_node mib_scalar_node;
+
+/** derived node, points to a fixed size const array
+    of sub-identifiers plus a 'child' pointer */
+struct mib_array_node
+{
+  /* inherited "base class" members */
+  void (*get_object_def)(u8_t ident_len, s32_t *ident, struct obj_def *od);
+  void (*get_value)(struct obj_def *od, u16_t len, void *value);
+  u8_t (*set_test)(struct obj_def *od, u16_t len, void *value);
+  void (*set_value)(struct obj_def *od, u16_t len, void *value);
+
+  u8_t node_type;
+  u16_t maxlength;
+
+  /* additional struct members */
+  const s32_t *objid;
+  struct mib_node* const *nptr;
+};
+
+/** derived node, points to a fixed size mem_malloced array
+    of sub-identifiers plus a 'child' pointer */
+struct mib_ram_array_node
+{
+  /* inherited "base class" members */
+  void (*get_object_def)(u8_t ident_len, s32_t *ident, struct obj_def *od);
+  void (*get_value)(struct obj_def *od, u16_t len, void *value);
+  u8_t (*set_test)(struct obj_def *od, u16_t len, void *value);
+  void (*set_value)(struct obj_def *od, u16_t len, void *value);
+
+  u8_t node_type;
+  u16_t maxlength;
+
+  /* aditional struct members */
+  s32_t *objid;
+  struct mib_node **nptr;
+};
+
+struct mib_list_node
+{
+  struct mib_list_node *prev;  
+  struct mib_list_node *next;
+  s32_t objid;
+  struct mib_node *nptr;
+};
+
+/** derived node, points to a doubly linked list
+    of sub-identifiers plus a 'child' pointer */
+struct mib_list_rootnode
+{
+  /* inherited "base class" members */
+  void (*get_object_def)(u8_t ident_len, s32_t *ident, struct obj_def *od);
+  void (*get_value)(struct obj_def *od, u16_t len, void *value);
+  u8_t (*set_test)(struct obj_def *od, u16_t len, void *value);
+  void (*set_value)(struct obj_def *od, u16_t len, void *value);
+
+  u8_t node_type;
+  u16_t maxlength;
+
+  /* additional struct members */
+  struct mib_list_node *head;
+  struct mib_list_node *tail;
+  /* counts list nodes in list  */
+  u16_t count;
+};
+
+/** derived node, has access functions for mib object in external memory or device
+    using 'tree_level' and 'idx', with a range 0 .. (level_length() - 1) */
+struct mib_external_node
+{
+  /* inherited "base class" members */
+  void (*get_object_def)(u8_t ident_len, s32_t *ident, struct obj_def *od);
+  void (*get_value)(struct obj_def *od, u16_t len, void *value);
+  u8_t (*set_test)(struct obj_def *od, u16_t len, void *value);
+  void (*set_value)(struct obj_def *od, u16_t len, void *value);
+
+  u8_t node_type;
+  u16_t maxlength;
+
+  /* additional struct members */
+  /** points to an external (in memory) record of some sort of addressing
+      information, passed to and interpreted by the funtions below */
+  void* addr_inf;
+  /** tree levels under this node */
+  u8_t tree_levels;
+  /** number of objects at this level */
+  u16_t (*level_length)(void* addr_inf, u8_t level);
+  /** compares object sub identifier with external id
+      return zero when equal, nonzero when unequal */
+  s32_t (*ident_cmp)(void* addr_inf, u8_t level, u16_t idx, s32_t sub_id);
+  void (*get_objid)(void* addr_inf, u8_t level, u16_t idx, s32_t *sub_id);
+
+  /** async Questions */
+  void (*get_object_def_q)(void* addr_inf, u8_t rid, u8_t ident_len, s32_t *ident);
+  void (*get_value_q)(u8_t rid, struct obj_def *od);
+  void (*set_test_q)(u8_t rid, struct obj_def *od);
+  void (*set_value_q)(u8_t rid, struct obj_def *od, u16_t len, void *value);
+  /** async Answers */
+  void (*get_object_def_a)(u8_t rid, u8_t ident_len, s32_t *ident, struct obj_def *od);
+  void (*get_value_a)(u8_t rid, struct obj_def *od, u16_t len, void *value);
+  u8_t (*set_test_a)(u8_t rid, struct obj_def *od, u16_t len, void *value);
+  void (*set_value_a)(u8_t rid, struct obj_def *od, u16_t len, void *value);
+  /** async Panic Close (agent returns error reply, 
+      e.g. used for external transaction cleanup) */
+  void (*get_object_def_pc)(u8_t rid, u8_t ident_len, s32_t *ident);
+  void (*get_value_pc)(u8_t rid, struct obj_def *od);
+  void (*set_test_pc)(u8_t rid, struct obj_def *od);
+  void (*set_value_pc)(u8_t rid, struct obj_def *od);
+};
+
+/** export MIB tree from mib2.c */
+extern const struct mib_array_node internet;
+
+/** dummy function pointers for non-leaf MIB nodes from mib2.c */
+void noleafs_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od);
+void noleafs_get_value(struct obj_def *od, u16_t len, void *value);
+u8_t noleafs_set_test(struct obj_def *od, u16_t len, void *value);
+void noleafs_set_value(struct obj_def *od, u16_t len, void *value);
+
+void snmp_oidtoip(s32_t *ident, ip_addr_t *ip);
+void snmp_iptooid(ip_addr_t *ip, s32_t *ident);
+void snmp_ifindextonetif(s32_t ifindex, struct netif **netif);
+void snmp_netiftoifindex(struct netif *netif, s32_t *ifidx);
+
+struct mib_list_node* snmp_mib_ln_alloc(s32_t id);
+void snmp_mib_ln_free(struct mib_list_node *ln);
+struct mib_list_rootnode* snmp_mib_lrn_alloc(void);
+void snmp_mib_lrn_free(struct mib_list_rootnode *lrn);
+
+s8_t snmp_mib_node_insert(struct mib_list_rootnode *rn, s32_t objid, struct mib_list_node **insn);
+s8_t snmp_mib_node_find(struct mib_list_rootnode *rn, s32_t objid, struct mib_list_node **fn);
+struct mib_list_rootnode *snmp_mib_node_delete(struct mib_list_rootnode *rn, struct mib_list_node *n);
+
+struct mib_node* snmp_search_tree(struct mib_node *node, u8_t ident_len, s32_t *ident, struct snmp_name_ptr *np);
+struct mib_node* snmp_expand_tree(struct mib_node *node, u8_t ident_len, s32_t *ident, struct snmp_obj_id *oidret);
+u8_t snmp_iso_prefix_tst(u8_t ident_len, s32_t *ident);
+u8_t snmp_iso_prefix_expand(u8_t ident_len, s32_t *ident, struct snmp_obj_id *oidret);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_SNMP */
+
+#endif /* __LWIP_SNMP_STRUCTS_H__ */
diff --git a/core/lwip/src/include/lwip/sockets.h b/core/lwip/src/include/lwip/sockets.h
new file mode 100644
index 00000000..3c8fed24
--- /dev/null
+++ b/core/lwip/src/include/lwip/sockets.h
@@ -0,0 +1,376 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+
+#ifndef __LWIP_SOCKETS_H__
+#define __LWIP_SOCKETS_H__
+
+#include "lwip/opt.h"
+
+#if LWIP_SOCKET /* don't build if not configured for use in lwipopts.h */
+
+#include <stddef.h> /* for size_t */
+
+#include "lwip/ip_addr.h"
+#include "lwip/inet.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* members are in network byte order */
+struct sockaddr_in {
+  u8_t sin_len;
+  u8_t sin_family;
+  u16_t sin_port;
+  struct in_addr sin_addr;
+  char sin_zero[8];
+};
+
+struct sockaddr {
+  u8_t sa_len;
+  u8_t sa_family;
+  char sa_data[14];
+};
+
+#ifndef socklen_t
+#  define socklen_t u32_t
+#endif
+
+/* Socket protocol types (TCP/UDP/RAW) */
+#define SOCK_STREAM     1
+#define SOCK_DGRAM      2
+#define SOCK_RAW        3
+
+/*
+ * Option flags per-socket. These must match the SOF_ flags in ip.h (checked in init.c)
+ */
+#define  SO_DEBUG       0x0001 /* Unimplemented: turn on debugging info recording */
+#define  SO_ACCEPTCONN  0x0002 /* socket has had listen() */
+#define  SO_REUSEADDR   0x0004 /* Allow local address reuse */
+#define  SO_KEEPALIVE   0x0008 /* keep connections alive */
+#define  SO_DONTROUTE   0x0010 /* Unimplemented: just use interface addresses */
+#define  SO_BROADCAST   0x0020 /* permit to send and to receive broadcast messages (see IP_SOF_BROADCAST option) */
+#define  SO_USELOOPBACK 0x0040 /* Unimplemented: bypass hardware when possible */
+#define  SO_LINGER      0x0080 /* linger on close if data present */
+#define  SO_OOBINLINE   0x0100 /* Unimplemented: leave received OOB data in line */
+#define  SO_REUSEPORT   0x0200 /* Unimplemented: allow local address & port reuse */
+
+#define SO_DONTLINGER   ((int)(~SO_LINGER))
+
+/*
+ * Additional options, not kept in so_options.
+ */
+#define SO_SNDBUF    0x1001    /* Unimplemented: send buffer size */
+#define SO_RCVBUF    0x1002    /* receive buffer size */
+#define SO_SNDLOWAT  0x1003    /* Unimplemented: send low-water mark */
+#define SO_RCVLOWAT  0x1004    /* Unimplemented: receive low-water mark */
+#define SO_SNDTIMEO  0x1005    /* Unimplemented: send timeout */
+#define SO_RCVTIMEO  0x1006    /* receive timeout */
+#define SO_ERROR     0x1007    /* get error status and clear */
+#define SO_TYPE      0x1008    /* get socket type */
+#define SO_CONTIMEO  0x1009    /* Unimplemented: connect timeout */
+#define SO_NO_CHECK  0x100a    /* don't create UDP checksum */
+
+
+/*
+ * Structure used for manipulating linger option.
+ */
+struct linger {
+       int l_onoff;                /* option on/off */
+       int l_linger;               /* linger time */
+};
+
+/*
+ * Level number for (get/set)sockopt() to apply to socket itself.
+ */
+#define  SOL_SOCKET  0xfff    /* options for socket level */
+
+
+#define AF_UNSPEC       0
+#define AF_INET         2
+#define PF_INET         AF_INET
+#define PF_UNSPEC       AF_UNSPEC
+
+#define IPPROTO_IP      0
+#define IPPROTO_TCP     6
+#define IPPROTO_UDP     17
+#define IPPROTO_UDPLITE 136
+
+/* Flags we can use with send and recv. */
+#define MSG_PEEK       0x01    /* Peeks at an incoming message */
+#define MSG_WAITALL    0x02    /* Unimplemented: Requests that the function block until the full amount of data requested can be returned */
+#define MSG_OOB        0x04    /* Unimplemented: Requests out-of-band data. The significance and semantics of out-of-band data are protocol-specific */
+#define MSG_DONTWAIT   0x08    /* Nonblocking i/o for this operation only */
+#define MSG_MORE       0x10    /* Sender will send more */
+
+
+/*
+ * Options for level IPPROTO_IP
+ */
+#define IP_TOS             1
+#define IP_TTL             2
+
+#if LWIP_TCP
+/*
+ * Options for level IPPROTO_TCP
+ */
+#define TCP_NODELAY    0x01    /* don't delay send to coalesce packets */
+#define TCP_KEEPALIVE  0x02    /* send KEEPALIVE probes when idle for pcb->keep_idle milliseconds */
+#define TCP_KEEPIDLE   0x03    /* set pcb->keep_idle  - Same as TCP_KEEPALIVE, but use seconds for get/setsockopt */
+#define TCP_KEEPINTVL  0x04    /* set pcb->keep_intvl - Use seconds for get/setsockopt */
+#define TCP_KEEPCNT    0x05    /* set pcb->keep_cnt   - Use number of probes sent for get/setsockopt */
+#endif /* LWIP_TCP */
+
+#if LWIP_UDP && LWIP_UDPLITE
+/*
+ * Options for level IPPROTO_UDPLITE
+ */
+#define UDPLITE_SEND_CSCOV 0x01 /* sender checksum coverage */
+#define UDPLITE_RECV_CSCOV 0x02 /* minimal receiver checksum coverage */
+#endif /* LWIP_UDP && LWIP_UDPLITE*/
+
+
+#if LWIP_IGMP
+/*
+ * Options and types for UDP multicast traffic handling
+ */
+#define IP_ADD_MEMBERSHIP  3
+#define IP_DROP_MEMBERSHIP 4
+#define IP_MULTICAST_TTL   5
+#define IP_MULTICAST_IF    6
+#define IP_MULTICAST_LOOP  7
+
+typedef struct ip_mreq {
+    struct in_addr imr_multiaddr; /* IP multicast address of group */
+    struct in_addr imr_interface; /* local IP address of interface */
+} ip_mreq;
+#endif /* LWIP_IGMP */
+
+/*
+ * The Type of Service provides an indication of the abstract
+ * parameters of the quality of service desired.  These parameters are
+ * to be used to guide the selection of the actual service parameters
+ * when transmitting a datagram through a particular network.  Several
+ * networks offer service precedence, which somehow treats high
+ * precedence traffic as more important than other traffic (generally
+ * by accepting only traffic above a certain precedence at time of high
+ * load).  The major choice is a three way tradeoff between low-delay,
+ * high-reliability, and high-throughput.
+ * The use of the Delay, Throughput, and Reliability indications may
+ * increase the cost (in some sense) of the service.  In many networks
+ * better performance for one of these parameters is coupled with worse
+ * performance on another.  Except for very unusual cases at most two
+ * of these three indications should be set.
+ */
+#define IPTOS_TOS_MASK          0x1E
+#define IPTOS_TOS(tos)          ((tos) & IPTOS_TOS_MASK)
+#define IPTOS_LOWDELAY          0x10
+#define IPTOS_THROUGHPUT        0x08
+#define IPTOS_RELIABILITY       0x04
+#define IPTOS_LOWCOST           0x02
+#define IPTOS_MINCOST           IPTOS_LOWCOST
+
+/*
+ * The Network Control precedence designation is intended to be used
+ * within a network only.  The actual use and control of that
+ * designation is up to each network. The Internetwork Control
+ * designation is intended for use by gateway control originators only.
+ * If the actual use of these precedence designations is of concern to
+ * a particular network, it is the responsibility of that network to
+ * control the access to, and use of, those precedence designations.
+ */
+#define IPTOS_PREC_MASK                 0xe0
+#define IPTOS_PREC(tos)                ((tos) & IPTOS_PREC_MASK)
+#define IPTOS_PREC_NETCONTROL           0xe0
+#define IPTOS_PREC_INTERNETCONTROL      0xc0
+#define IPTOS_PREC_CRITIC_ECP           0xa0
+#define IPTOS_PREC_FLASHOVERRIDE        0x80
+#define IPTOS_PREC_FLASH                0x60
+#define IPTOS_PREC_IMMEDIATE            0x40
+#define IPTOS_PREC_PRIORITY             0x20
+#define IPTOS_PREC_ROUTINE              0x00
+
+
+/*
+ * Commands for ioctlsocket(),  taken from the BSD file fcntl.h.
+ * lwip_ioctl only supports FIONREAD and FIONBIO, for now
+ *
+ * Ioctl's have the command encoded in the lower word,
+ * and the size of any in or out parameters in the upper
+ * word.  The high 2 bits of the upper word are used
+ * to encode the in/out status of the parameter; for now
+ * we restrict parameters to at most 128 bytes.
+ */
+#if !defined(FIONREAD) || !defined(FIONBIO)
+#define IOCPARM_MASK    0x7fU           /* parameters must be < 128 bytes */
+#define IOC_VOID        0x20000000UL    /* no parameters */
+#define IOC_OUT         0x40000000UL    /* copy out parameters */
+#define IOC_IN          0x80000000UL    /* copy in parameters */
+#define IOC_INOUT       (IOC_IN|IOC_OUT)
+                                        /* 0x20000000 distinguishes new &
+                                           old ioctl's */
+#define _IO(x,y)        (IOC_VOID|((x)<<8)|(y))
+
+#define _IOR(x,y,t)     (IOC_OUT|(((long)sizeof(t)&IOCPARM_MASK)<<16)|((x)<<8)|(y))
+
+#define _IOW(x,y,t)     (IOC_IN|(((long)sizeof(t)&IOCPARM_MASK)<<16)|((x)<<8)|(y))
+#endif /* !defined(FIONREAD) || !defined(FIONBIO) */
+
+#ifndef FIONREAD
+#define FIONREAD    _IOR('f', 127, unsigned long) /* get # bytes to read */
+#endif
+#ifndef FIONBIO
+#define FIONBIO     _IOW('f', 126, unsigned long) /* set/clear non-blocking i/o */
+#endif
+
+/* Socket I/O Controls: unimplemented */
+#ifndef SIOCSHIWAT
+#define SIOCSHIWAT  _IOW('s',  0, unsigned long)  /* set high watermark */
+#define SIOCGHIWAT  _IOR('s',  1, unsigned long)  /* get high watermark */
+#define SIOCSLOWAT  _IOW('s',  2, unsigned long)  /* set low watermark */
+#define SIOCGLOWAT  _IOR('s',  3, unsigned long)  /* get low watermark */
+#define SIOCATMARK  _IOR('s',  7, unsigned long)  /* at oob mark? */
+#endif
+
+/* commands for fnctl */
+#ifndef F_GETFL
+#define F_GETFL 3
+#endif
+#ifndef F_SETFL
+#define F_SETFL 4
+#endif
+
+/* File status flags and file access modes for fnctl,
+   these are bits in an int. */
+#ifndef O_NONBLOCK
+#define O_NONBLOCK  1 /* nonblocking I/O */
+#endif
+#ifndef O_NDELAY
+#define O_NDELAY    1 /* same as O_NONBLOCK, for compatibility */
+#endif
+
+#ifndef SHUT_RD
+  #define SHUT_RD   0
+  #define SHUT_WR   1
+  #define SHUT_RDWR 2
+#endif
+
+/* FD_SET used for lwip_select */
+#ifndef FD_SET
+  #undef  FD_SETSIZE
+  /* Make FD_SETSIZE match NUM_SOCKETS in socket.c */
+  #define FD_SETSIZE    MEMP_NUM_NETCONN
+  #define FD_SET(n, p)  ((p)->fd_bits[(n)/8] |=  (1 << ((n) & 7)))
+  #define FD_CLR(n, p)  ((p)->fd_bits[(n)/8] &= ~(1 << ((n) & 7)))
+  #define FD_ISSET(n,p) ((p)->fd_bits[(n)/8] &   (1 << ((n) & 7)))
+  #define FD_ZERO(p)    memset((void*)(p),0,sizeof(*(p)))
+
+  typedef struct fd_set {
+          unsigned char fd_bits [(FD_SETSIZE+7)/8];
+        } fd_set;
+
+#endif /* FD_SET */
+
+/** LWIP_TIMEVAL_PRIVATE: if you want to use the struct timeval provided
+ * by your system, set this to 0 and include <sys/time.h> in cc.h */ 
+#ifndef LWIP_TIMEVAL_PRIVATE
+#define LWIP_TIMEVAL_PRIVATE 1
+#endif
+
+#if LWIP_TIMEVAL_PRIVATE
+struct timeval {
+  long    tv_sec;         /* seconds */
+  long    tv_usec;        /* and microseconds */
+};
+#endif /* LWIP_TIMEVAL_PRIVATE */
+
+void lwip_socket_init(void);
+
+int lwip_accept(int s, struct sockaddr *addr, socklen_t *addrlen);
+int lwip_bind(int s, const struct sockaddr *name, socklen_t namelen);
+int lwip_shutdown(int s, int how);
+int lwip_getpeername (int s, struct sockaddr *name, socklen_t *namelen);
+int lwip_getsockname (int s, struct sockaddr *name, socklen_t *namelen);
+int lwip_getsockopt (int s, int level, int optname, void *optval, socklen_t *optlen);
+int lwip_setsockopt (int s, int level, int optname, const void *optval, socklen_t optlen);
+int lwip_close(int s);
+int lwip_connect(int s, const struct sockaddr *name, socklen_t namelen);
+int lwip_listen(int s, int backlog);
+int lwip_recv(int s, void *mem, size_t len, int flags);
+int lwip_read(int s, void *mem, size_t len);
+int lwip_recvfrom(int s, void *mem, size_t len, int flags,
+      struct sockaddr *from, socklen_t *fromlen);
+int lwip_send(int s, const void *dataptr, size_t size, int flags);
+int lwip_sendto(int s, const void *dataptr, size_t size, int flags,
+    const struct sockaddr *to, socklen_t tolen);
+int lwip_socket(int domain, int type, int protocol);
+int lwip_write(int s, const void *dataptr, size_t size);
+int lwip_select(int maxfdp1, fd_set *readset, fd_set *writeset, fd_set *exceptset,
+                struct timeval *timeout);
+int lwip_ioctl(int s, long cmd, void *argp);
+int lwip_fcntl(int s, int cmd, int val);
+
+#if LWIP_COMPAT_SOCKETS
+#define accept(a,b,c)         lwip_accept(a,b,c)
+#define bind(a,b,c)           lwip_bind(a,b,c)
+#define shutdown(a,b)         lwip_shutdown(a,b)
+#define closesocket(s)        lwip_close(s)
+#define connect(a,b,c)        lwip_connect(a,b,c)
+#define getsockname(a,b,c)    lwip_getsockname(a,b,c)
+#define getpeername(a,b,c)    lwip_getpeername(a,b,c)
+#define setsockopt(a,b,c,d,e) lwip_setsockopt(a,b,c,d,e)
+#define getsockopt(a,b,c,d,e) lwip_getsockopt(a,b,c,d,e)
+#define listen(a,b)           lwip_listen(a,b)
+#define recv(a,b,c,d)         lwip_recv(a,b,c,d)
+#define recvfrom(a,b,c,d,e,f) lwip_recvfrom(a,b,c,d,e,f)
+#define send(a,b,c,d)         lwip_send(a,b,c,d)
+#define sendto(a,b,c,d,e,f)   lwip_sendto(a,b,c,d,e,f)
+#define socket(a,b,c)         lwip_socket(a,b,c)
+#define select(a,b,c,d,e)     lwip_select(a,b,c,d,e)
+#define ioctlsocket(a,b,c)    lwip_ioctl(a,b,c)
+
+#if LWIP_POSIX_SOCKETS_IO_NAMES
+#define read(a,b,c)           lwip_read(a,b,c)
+#define write(a,b,c)          lwip_write(a,b,c)
+#define close(s)              lwip_close(s)
+#endif /* LWIP_POSIX_SOCKETS_IO_NAMES */
+
+#endif /* LWIP_COMPAT_SOCKETS */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_SOCKET */
+
+#endif /* __LWIP_SOCKETS_H__ */
diff --git a/core/lwip/src/include/lwip/stats.h b/core/lwip/src/include/lwip/stats.h
new file mode 100644
index 00000000..015b7ce7
--- /dev/null
+++ b/core/lwip/src/include/lwip/stats.h
@@ -0,0 +1,292 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_STATS_H__
+#define __LWIP_STATS_H__
+
+#include "lwip/opt.h"
+
+#include "lwip/mem.h"
+#include "lwip/memp.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if LWIP_STATS
+
+#ifndef LWIP_STATS_LARGE
+#define LWIP_STATS_LARGE 0
+#endif
+
+#if LWIP_STATS_LARGE
+#define STAT_COUNTER     u32_t
+#define STAT_COUNTER_F   U32_F
+#else
+#define STAT_COUNTER     u16_t
+#define STAT_COUNTER_F   U16_F
+#endif 
+
+struct stats_proto {
+  STAT_COUNTER xmit;             /* Transmitted packets. */
+  STAT_COUNTER recv;             /* Received packets. */
+  STAT_COUNTER fw;               /* Forwarded packets. */
+  STAT_COUNTER drop;             /* Dropped packets. */
+  STAT_COUNTER chkerr;           /* Checksum error. */
+  STAT_COUNTER lenerr;           /* Invalid length error. */
+  STAT_COUNTER memerr;           /* Out of memory error. */
+  STAT_COUNTER rterr;            /* Routing error. */
+  STAT_COUNTER proterr;          /* Protocol error. */
+  STAT_COUNTER opterr;           /* Error in options. */
+  STAT_COUNTER err;              /* Misc error. */
+  STAT_COUNTER cachehit;
+};
+
+struct stats_igmp {
+  STAT_COUNTER xmit;             /* Transmitted packets. */
+  STAT_COUNTER recv;             /* Received packets. */
+  STAT_COUNTER drop;             /* Dropped packets. */
+  STAT_COUNTER chkerr;           /* Checksum error. */
+  STAT_COUNTER lenerr;           /* Invalid length error. */
+  STAT_COUNTER memerr;           /* Out of memory error. */
+  STAT_COUNTER proterr;          /* Protocol error. */
+  STAT_COUNTER rx_v1;            /* Received v1 frames. */
+  STAT_COUNTER rx_group;         /* Received group-specific queries. */
+  STAT_COUNTER rx_general;       /* Received general queries. */
+  STAT_COUNTER rx_report;        /* Received reports. */
+  STAT_COUNTER tx_join;          /* Sent joins. */
+  STAT_COUNTER tx_leave;         /* Sent leaves. */
+  STAT_COUNTER tx_report;        /* Sent reports. */
+};
+
+struct stats_mem {
+#ifdef LWIP_DEBUG
+  const char *name;
+#endif /* LWIP_DEBUG */
+  mem_size_t avail;
+  mem_size_t used;
+  mem_size_t max;
+  STAT_COUNTER err;
+  STAT_COUNTER illegal;
+};
+
+struct stats_syselem {
+  STAT_COUNTER used;
+  STAT_COUNTER max;
+  STAT_COUNTER err;
+};
+
+struct stats_sys {
+  struct stats_syselem sem;
+  struct stats_syselem mutex;
+  struct stats_syselem mbox;
+};
+
+struct stats_ {
+#if LINK_STATS
+  struct stats_proto link;
+#endif
+#if ETHARP_STATS
+  struct stats_proto etharp;
+#endif
+#if IPFRAG_STATS
+  struct stats_proto ip_frag;
+#endif
+#if IP_STATS
+  struct stats_proto ip;
+#endif
+#if ICMP_STATS
+  struct stats_proto icmp;
+#endif
+#if IGMP_STATS
+  struct stats_igmp igmp;
+#endif
+#if UDP_STATS
+  struct stats_proto udp;
+#endif
+#if TCP_STATS
+  struct stats_proto tcp;
+#endif
+#if MEM_STATS
+  struct stats_mem mem;
+#endif
+#if MEMP_STATS
+  struct stats_mem memp[MEMP_MAX];
+#endif
+#if SYS_STATS
+  struct stats_sys sys;
+#endif
+};
+
+extern struct stats_ lwip_stats;
+
+void stats_init(void);
+
+#define STATS_INC(x) ++lwip_stats.x
+#define STATS_DEC(x) --lwip_stats.x
+#define STATS_INC_USED(x, y) do { lwip_stats.x.used += y; \
+                                if (lwip_stats.x.max < lwip_stats.x.used) { \
+                                    lwip_stats.x.max = lwip_stats.x.used; \
+                                } \
+                             } while(0)
+#else /* LWIP_STATS */
+#define stats_init()
+#define STATS_INC(x)
+#define STATS_DEC(x)
+#define STATS_INC_USED(x)
+#endif /* LWIP_STATS */
+
+#if TCP_STATS
+#define TCP_STATS_INC(x) STATS_INC(x)
+#define TCP_STATS_DISPLAY() stats_display_proto(&lwip_stats.tcp, "TCP")
+#else
+#define TCP_STATS_INC(x)
+#define TCP_STATS_DISPLAY()
+#endif
+
+#if UDP_STATS
+#define UDP_STATS_INC(x) STATS_INC(x)
+#define UDP_STATS_DISPLAY() stats_display_proto(&lwip_stats.udp, "UDP")
+#else
+#define UDP_STATS_INC(x)
+#define UDP_STATS_DISPLAY()
+#endif
+
+#if ICMP_STATS
+#define ICMP_STATS_INC(x) STATS_INC(x)
+#define ICMP_STATS_DISPLAY() stats_display_proto(&lwip_stats.icmp, "ICMP")
+#else
+#define ICMP_STATS_INC(x)
+#define ICMP_STATS_DISPLAY()
+#endif
+
+#if IGMP_STATS
+#define IGMP_STATS_INC(x) STATS_INC(x)
+#define IGMP_STATS_DISPLAY() stats_display_igmp(&lwip_stats.igmp)
+#else
+#define IGMP_STATS_INC(x)
+#define IGMP_STATS_DISPLAY()
+#endif
+
+#if IP_STATS
+#define IP_STATS_INC(x) STATS_INC(x)
+#define IP_STATS_DISPLAY() stats_display_proto(&lwip_stats.ip, "IP")
+#else
+#define IP_STATS_INC(x)
+#define IP_STATS_DISPLAY()
+#endif
+
+#if IPFRAG_STATS
+#define IPFRAG_STATS_INC(x) STATS_INC(x)
+#define IPFRAG_STATS_DISPLAY() stats_display_proto(&lwip_stats.ip_frag, "IP_FRAG")
+#else
+#define IPFRAG_STATS_INC(x)
+#define IPFRAG_STATS_DISPLAY()
+#endif
+
+#if ETHARP_STATS
+#define ETHARP_STATS_INC(x) STATS_INC(x)
+#define ETHARP_STATS_DISPLAY() stats_display_proto(&lwip_stats.etharp, "ETHARP")
+#else
+#define ETHARP_STATS_INC(x)
+#define ETHARP_STATS_DISPLAY()
+#endif
+
+#if LINK_STATS
+#define LINK_STATS_INC(x) STATS_INC(x)
+#define LINK_STATS_DISPLAY() stats_display_proto(&lwip_stats.link, "LINK")
+#else
+#define LINK_STATS_INC(x)
+#define LINK_STATS_DISPLAY()
+#endif
+
+#if MEM_STATS
+#define MEM_STATS_AVAIL(x, y) lwip_stats.mem.x = y
+#define MEM_STATS_INC(x) STATS_INC(mem.x)
+#define MEM_STATS_INC_USED(x, y) STATS_INC_USED(mem, y)
+#define MEM_STATS_DEC_USED(x, y) lwip_stats.mem.x -= y
+#define MEM_STATS_DISPLAY() stats_display_mem(&lwip_stats.mem, "HEAP")
+#else
+#define MEM_STATS_AVAIL(x, y)
+#define MEM_STATS_INC(x)
+#define MEM_STATS_INC_USED(x, y)
+#define MEM_STATS_DEC_USED(x, y)
+#define MEM_STATS_DISPLAY()
+#endif
+
+#if MEMP_STATS
+#define MEMP_STATS_AVAIL(x, i, y) lwip_stats.memp[i].x = y
+#define MEMP_STATS_INC(x, i) STATS_INC(memp[i].x)
+#define MEMP_STATS_DEC(x, i) STATS_DEC(memp[i].x)
+#define MEMP_STATS_INC_USED(x, i) STATS_INC_USED(memp[i], 1)
+#define MEMP_STATS_DISPLAY(i) stats_display_memp(&lwip_stats.memp[i], i)
+#else
+#define MEMP_STATS_AVAIL(x, i, y)
+#define MEMP_STATS_INC(x, i)
+#define MEMP_STATS_DEC(x, i)
+#define MEMP_STATS_INC_USED(x, i)
+#define MEMP_STATS_DISPLAY(i)
+#endif
+
+#if SYS_STATS
+#define SYS_STATS_INC(x) STATS_INC(sys.x)
+#define SYS_STATS_DEC(x) STATS_DEC(sys.x)
+#define SYS_STATS_INC_USED(x) STATS_INC_USED(sys.x, 1)
+#define SYS_STATS_DISPLAY() stats_display_sys(&lwip_stats.sys)
+#else
+#define SYS_STATS_INC(x)
+#define SYS_STATS_DEC(x)
+#define SYS_STATS_INC_USED(x)
+#define SYS_STATS_DISPLAY()
+#endif
+
+/* Display of statistics */
+#if LWIP_STATS_DISPLAY
+void stats_display(void);
+void stats_display_proto(struct stats_proto *proto, char *name);
+void stats_display_igmp(struct stats_igmp *igmp);
+void stats_display_mem(struct stats_mem *mem, char *name);
+void stats_display_memp(struct stats_mem *mem, int index);
+void stats_display_sys(struct stats_sys *sys);
+#else /* LWIP_STATS_DISPLAY */
+#define stats_display()
+#define stats_display_proto(proto, name)
+#define stats_display_igmp(igmp)
+#define stats_display_mem(mem, name)
+#define stats_display_memp(mem, index)
+#define stats_display_sys(sys)
+#endif /* LWIP_STATS_DISPLAY */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_STATS_H__ */
diff --git a/core/lwip/src/include/lwip/sys.h b/core/lwip/src/include/lwip/sys.h
new file mode 100644
index 00000000..9f62c754
--- /dev/null
+++ b/core/lwip/src/include/lwip/sys.h
@@ -0,0 +1,331 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_SYS_H__
+#define __LWIP_SYS_H__
+
+#include "lwip/opt.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if NO_SYS
+
+/* For a totally minimal and standalone system, we provide null
+   definitions of the sys_ functions. */
+typedef u8_t sys_sem_t;
+typedef u8_t sys_mutex_t;
+typedef u8_t sys_mbox_t;
+
+#define sys_sem_new(s, c) ERR_OK
+#define sys_sem_signal(s)
+#define sys_sem_wait(s)
+#define sys_arch_sem_wait(s,t)
+#define sys_sem_free(s)
+#define sys_mutex_new(mu) ERR_OK
+#define sys_mutex_lock(mu)
+#define sys_mutex_unlock(mu)
+#define sys_mutex_free(mu)
+#define sys_mbox_new(m, s) ERR_OK
+#define sys_mbox_fetch(m,d)
+#define sys_mbox_tryfetch(m,d)
+#define sys_mbox_post(m,d)
+#define sys_mbox_trypost(m,d)
+#define sys_mbox_free(m)
+
+#define sys_thread_new(n,t,a,s,p)
+
+#define sys_msleep(t)
+
+#else /* NO_SYS */
+
+/** Return code for timeouts from sys_arch_mbox_fetch and sys_arch_sem_wait */
+#define SYS_ARCH_TIMEOUT 0xffffffffUL
+
+/** sys_mbox_tryfetch() returns SYS_MBOX_EMPTY if appropriate.
+ * For now we use the same magic value, but we allow this to change in future.
+ */
+#define SYS_MBOX_EMPTY SYS_ARCH_TIMEOUT 
+
+#include "lwip/err.h"
+#include "arch/sys_arch.h"
+
+/** Function prototype for thread functions */
+typedef void (*lwip_thread_fn)(void *arg);
+
+/* Function prototypes for functions to be implemented by platform ports
+   (in sys_arch.c) */
+
+/* Mutex functions: */
+
+/** Define LWIP_COMPAT_MUTEX if the port has no mutexes and binary semaphores
+    should be used instead */
+#if LWIP_COMPAT_MUTEX
+/* for old ports that don't have mutexes: define them to binary semaphores */
+#define sys_mutex_t                   sys_sem_t
+#define sys_mutex_new(mutex)          sys_sem_new(mutex, 1)
+#define sys_mutex_lock(mutex)         sys_sem_wait(mutex)
+#define sys_mutex_unlock(mutex)       sys_sem_signal(mutex)
+#define sys_mutex_free(mutex)         sys_sem_free(mutex)
+#define sys_mutex_valid(mutex)        sys_sem_valid(mutex)
+#define sys_mutex_set_invalid(mutex)  sys_sem_set_invalid(mutex)
+
+#else /* LWIP_COMPAT_MUTEX */
+
+/** Create a new mutex
+ * @param mutex pointer to the mutex to create
+ * @return a new mutex */
+err_t sys_mutex_new(sys_mutex_t *mutex);
+/** Lock a mutex
+ * @param mutex the mutex to lock */
+void sys_mutex_lock(sys_mutex_t *mutex);
+/** Unlock a mutex
+ * @param mutex the mutex to unlock */
+void sys_mutex_unlock(sys_mutex_t *mutex);
+/** Delete a semaphore
+ * @param mutex the mutex to delete */
+void sys_mutex_free(sys_mutex_t *mutex); 
+#ifndef sys_mutex_valid
+/** Check if a mutex is valid/allocated: return 1 for valid, 0 for invalid */
+int sys_mutex_valid(sys_mutex_t *mutex);
+#endif
+#ifndef sys_mutex_set_invalid
+/** Set a mutex invalid so that sys_mutex_valid returns 0 */
+void sys_mutex_set_invalid(sys_mutex_t *mutex);
+#endif
+#endif /* LWIP_COMPAT_MUTEX */
+
+/* Semaphore functions: */
+
+/** Create a new semaphore
+ * @param sem pointer to the semaphore to create
+ * @param count initial count of the semaphore
+ * @return ERR_OK if successful, another err_t otherwise */
+err_t sys_sem_new(sys_sem_t *sem, u8_t count);
+/** Signals a semaphore
+ * @param sem the semaphore to signal */
+void sys_sem_signal(sys_sem_t *sem);
+/** Wait for a semaphore for the specified timeout
+ * @param sem the semaphore to wait for
+ * @param timeout timeout in milliseconds to wait (0 = wait forever)
+ * @return time (in milliseconds) waited for the semaphore
+ *         or SYS_ARCH_TIMEOUT on timeout */
+u32_t sys_arch_sem_wait(sys_sem_t *sem, u32_t timeout);
+/** Delete a semaphore
+ * @param sem semaphore to delete */
+void sys_sem_free(sys_sem_t *sem);
+/** Wait for a semaphore - forever/no timeout */
+#define sys_sem_wait(sem)                  sys_arch_sem_wait(sem, 0)
+#ifndef sys_sem_valid
+/** Check if a sempahore is valid/allocated: return 1 for valid, 0 for invalid */
+int sys_sem_valid(sys_sem_t *sem);
+#endif
+#ifndef sys_sem_set_invalid
+/** Set a semaphore invalid so that sys_sem_valid returns 0 */
+void sys_sem_set_invalid(sys_sem_t *sem);
+#endif
+
+/* Time functions. */
+#ifndef sys_msleep
+void sys_msleep(u32_t ms); /* only has a (close to) 1 jiffy resolution. */
+#endif
+
+/* Mailbox functions. */
+
+/** Create a new mbox of specified size
+ * @param mbox pointer to the mbox to create
+ * @param size (miminum) number of messages in this mbox
+ * @return ERR_OK if successful, another err_t otherwise */
+err_t sys_mbox_new(sys_mbox_t *mbox, int size);
+/** Post a message to an mbox - may not fail
+ * -> blocks if full, only used from tasks not from ISR
+ * @param mbox mbox to posts the message
+ * @param msg message to post (ATTENTION: can be NULL) */
+void sys_mbox_post(sys_mbox_t *mbox, void *msg);
+/** Try to post a message to an mbox - may fail if full or ISR
+ * @param mbox mbox to posts the message
+ * @param msg message to post (ATTENTION: can be NULL) */
+err_t sys_mbox_trypost(sys_mbox_t *mbox, void *msg);
+/** Wait for a new message to arrive in the mbox
+ * @param mbox mbox to get a message from
+ * @param msg pointer where the message is stored
+ * @param timeout maximum time (in milliseconds) to wait for a message
+ * @return time (in milliseconds) waited for a message, may be 0 if not waited
+           or SYS_ARCH_TIMEOUT on timeout
+ *         The returned time has to be accurate to prevent timer jitter! */
+u32_t sys_arch_mbox_fetch(sys_mbox_t *mbox, void **msg, u32_t timeout);
+/* Allow port to override with a macro, e.g. special timout for sys_arch_mbox_fetch() */
+#ifndef sys_arch_mbox_tryfetch
+/** Wait for a new message to arrive in the mbox
+ * @param mbox mbox to get a message from
+ * @param msg pointer where the message is stored
+ * @param timeout maximum time (in milliseconds) to wait for a message
+ * @return 0 (milliseconds) if a message has been received
+ *         or SYS_MBOX_EMPTY if the mailbox is empty */
+u32_t sys_arch_mbox_tryfetch(sys_mbox_t *mbox, void **msg);
+#endif
+/** For now, we map straight to sys_arch implementation. */
+#define sys_mbox_tryfetch(mbox, msg) sys_arch_mbox_tryfetch(mbox, msg)
+/** Delete an mbox
+ * @param mbox mbox to delete */
+void sys_mbox_free(sys_mbox_t *mbox);
+#define sys_mbox_fetch(mbox, msg) sys_arch_mbox_fetch(mbox, msg, 0)
+#ifndef sys_mbox_valid
+/** Check if an mbox is valid/allocated: return 1 for valid, 0 for invalid */
+int sys_mbox_valid(sys_mbox_t *mbox);
+#endif
+#ifndef sys_mbox_set_invalid
+/** Set an mbox invalid so that sys_mbox_valid returns 0 */
+void sys_mbox_set_invalid(sys_mbox_t *mbox);
+#endif
+
+/** The only thread function:
+ * Creates a new thread
+ * @param name human-readable name for the thread (used for debugging purposes)
+ * @param thread thread-function
+ * @param arg parameter passed to 'thread'
+ * @param stacksize stack size in bytes for the new thread (may be ignored by ports)
+ * @param prio priority of the new thread (may be ignored by ports) */
+sys_thread_t sys_thread_new(const char *name, lwip_thread_fn thread, void *arg, int stacksize, int prio);
+
+#endif /* NO_SYS */
+
+/* sys_init() must be called before anthing else. */
+void sys_init(void);
+
+#ifndef sys_jiffies
+/** Ticks/jiffies since power up. */
+u32_t sys_jiffies(void);
+#endif
+
+/** Returns the current time in milliseconds,
+ * may be the same as sys_jiffies or at least based on it. */
+u32_t sys_now(void);
+
+/* Critical Region Protection */
+/* These functions must be implemented in the sys_arch.c file.
+   In some implementations they can provide a more light-weight protection
+   mechanism than using semaphores. Otherwise semaphores can be used for
+   implementation */
+#ifndef SYS_ARCH_PROTECT
+/** SYS_LIGHTWEIGHT_PROT
+ * define SYS_LIGHTWEIGHT_PROT in lwipopts.h if you want inter-task protection
+ * for certain critical regions during buffer allocation, deallocation and memory
+ * allocation and deallocation.
+ */
+#if SYS_LIGHTWEIGHT_PROT
+
+/** SYS_ARCH_DECL_PROTECT
+ * declare a protection variable. This macro will default to defining a variable of
+ * type sys_prot_t. If a particular port needs a different implementation, then
+ * this macro may be defined in sys_arch.h.
+ */
+#define SYS_ARCH_DECL_PROTECT(lev) sys_prot_t lev
+/** SYS_ARCH_PROTECT
+ * Perform a "fast" protect. This could be implemented by
+ * disabling interrupts for an embedded system or by using a semaphore or
+ * mutex. The implementation should allow calling SYS_ARCH_PROTECT when
+ * already protected. The old protection level is returned in the variable
+ * "lev". This macro will default to calling the sys_arch_protect() function
+ * which should be implemented in sys_arch.c. If a particular port needs a
+ * different implementation, then this macro may be defined in sys_arch.h
+ */
+#define SYS_ARCH_PROTECT(lev) lev = sys_arch_protect()
+/** SYS_ARCH_UNPROTECT
+ * Perform a "fast" set of the protection level to "lev". This could be
+ * implemented by setting the interrupt level to "lev" within the MACRO or by
+ * using a semaphore or mutex.  This macro will default to calling the
+ * sys_arch_unprotect() function which should be implemented in
+ * sys_arch.c. If a particular port needs a different implementation, then
+ * this macro may be defined in sys_arch.h
+ */
+#define SYS_ARCH_UNPROTECT(lev) sys_arch_unprotect(lev)
+sys_prot_t sys_arch_protect(void);
+void sys_arch_unprotect(sys_prot_t pval);
+
+#else
+
+#define SYS_ARCH_DECL_PROTECT(lev)
+#define SYS_ARCH_PROTECT(lev)
+#define SYS_ARCH_UNPROTECT(lev)
+
+#endif /* SYS_LIGHTWEIGHT_PROT */
+
+#endif /* SYS_ARCH_PROTECT */
+
+/*
+ * Macros to set/get and increase/decrease variables in a thread-safe way.
+ * Use these for accessing variable that are used from more than one thread.
+ */
+
+#ifndef SYS_ARCH_INC
+#define SYS_ARCH_INC(var, val) do { \
+                                SYS_ARCH_DECL_PROTECT(old_level); \
+                                SYS_ARCH_PROTECT(old_level); \
+                                var += val; \
+                                SYS_ARCH_UNPROTECT(old_level); \
+                              } while(0)
+#endif /* SYS_ARCH_INC */
+
+#ifndef SYS_ARCH_DEC
+#define SYS_ARCH_DEC(var, val) do { \
+                                SYS_ARCH_DECL_PROTECT(old_level); \
+                                SYS_ARCH_PROTECT(old_level); \
+                                var -= val; \
+                                SYS_ARCH_UNPROTECT(old_level); \
+                              } while(0)
+#endif /* SYS_ARCH_DEC */
+
+#ifndef SYS_ARCH_GET
+#define SYS_ARCH_GET(var, ret) do { \
+                                SYS_ARCH_DECL_PROTECT(old_level); \
+                                SYS_ARCH_PROTECT(old_level); \
+                                ret = var; \
+                                SYS_ARCH_UNPROTECT(old_level); \
+                              } while(0)
+#endif /* SYS_ARCH_GET */
+
+#ifndef SYS_ARCH_SET
+#define SYS_ARCH_SET(var, val) do { \
+                                SYS_ARCH_DECL_PROTECT(old_level); \
+                                SYS_ARCH_PROTECT(old_level); \
+                                var = val; \
+                                SYS_ARCH_UNPROTECT(old_level); \
+                              } while(0)
+#endif /* SYS_ARCH_SET */
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LWIP_SYS_H__ */
diff --git a/core/lwip/src/include/lwip/tcp.h b/core/lwip/src/include/lwip/tcp.h
new file mode 100644
index 00000000..07dcd10e
--- /dev/null
+++ b/core/lwip/src/include/lwip/tcp.h
@@ -0,0 +1,377 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_TCP_H__
+#define __LWIP_TCP_H__
+
+#include "lwip/opt.h"
+
+#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/sys.h"
+#include "lwip/mem.h"
+#include "lwip/pbuf.h"
+#include "lwip/ip.h"
+#include "lwip/icmp.h"
+#include "lwip/err.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct tcp_pcb;
+
+/** Function prototype for tcp accept callback functions. Called when a new
+ * connection can be accepted on a listening pcb.
+ *
+ * @param arg Additional argument to pass to the callback function (@see tcp_arg())
+ * @param newpcb The new connection pcb
+ * @param err An error code if there has been an error accepting.
+ *            Only return ERR_ABRT if you have called tcp_abort from within the
+ *            callback function!
+ */
+typedef err_t (*tcp_accept_fn)(void *arg, struct tcp_pcb *newpcb, err_t err);
+
+/** Function prototype for tcp receive callback functions. Called when data has
+ * been received.
+ *
+ * @param arg Additional argument to pass to the callback function (@see tcp_arg())
+ * @param tpcb The connection pcb which received data
+ * @param p The received data (or NULL when the connection has been closed!)
+ * @param err An error code if there has been an error receiving
+ *            Only return ERR_ABRT if you have called tcp_abort from within the
+ *            callback function!
+ */
+typedef err_t (*tcp_recv_fn)(void *arg, struct tcp_pcb *tpcb,
+                             struct pbuf *p, err_t err);
+
+/** Function prototype for tcp sent callback functions. Called when sent data has
+ * been acknowledged by the remote side. Use it to free corresponding resources.
+ * This also means that the pcb has now space available to send new data.
+ *
+ * @param arg Additional argument to pass to the callback function (@see tcp_arg())
+ * @param tpcb The connection pcb for which data has been acknowledged
+ * @param len The amount of bytes acknowledged
+ * @return ERR_OK: try to send some data by calling tcp_output
+ *            Only return ERR_ABRT if you have called tcp_abort from within the
+ *            callback function!
+ */
+typedef err_t (*tcp_sent_fn)(void *arg, struct tcp_pcb *tpcb,
+                              u16_t len);
+
+/** Function prototype for tcp poll callback functions. Called periodically as
+ * specified by @see tcp_poll.
+ *
+ * @param arg Additional argument to pass to the callback function (@see tcp_arg())
+ * @param tpcb tcp pcb
+ * @return ERR_OK: try to send some data by calling tcp_output
+ *            Only return ERR_ABRT if you have called tcp_abort from within the
+ *            callback function!
+ */
+typedef err_t (*tcp_poll_fn)(void *arg, struct tcp_pcb *tpcb);
+
+/** Function prototype for tcp error callback functions. Called when the pcb
+ * receives a RST or is unexpectedly closed for any other reason.
+ *
+ * @note The corresponding pcb is already freed when this callback is called!
+ *
+ * @param arg Additional argument to pass to the callback function (@see tcp_arg())
+ * @param err Error code to indicate why the pcb has been closed
+ *            ERR_ABRT: aborted through tcp_abort or by a TCP timer
+ *            ERR_RST: the connection was reset by the remote host
+ */
+typedef void  (*tcp_err_fn)(void *arg, err_t err);
+
+/** Function prototype for tcp connected callback functions. Called when a pcb
+ * is connected to the remote side after initiating a connection attempt by
+ * calling tcp_connect().
+ *
+ * @param arg Additional argument to pass to the callback function (@see tcp_arg())
+ * @param tpcb The connection pcb which is connected
+ * @param err An unused error code, always ERR_OK currently ;-) TODO!
+ *            Only return ERR_ABRT if you have called tcp_abort from within the
+ *            callback function!
+ *
+ * @note When a connection attempt fails, the error callback is currently called!
+ */
+typedef err_t (*tcp_connected_fn)(void *arg, struct tcp_pcb *tpcb, err_t err);
+
+enum tcp_state {
+  CLOSED      = 0,
+  LISTEN      = 1,
+  SYN_SENT    = 2,
+  SYN_RCVD    = 3,
+  ESTABLISHED = 4,
+  FIN_WAIT_1  = 5,
+  FIN_WAIT_2  = 6,
+  CLOSE_WAIT  = 7,
+  CLOSING     = 8,
+  LAST_ACK    = 9,
+  TIME_WAIT   = 10
+};
+
+#if LWIP_CALLBACK_API
+  /* Function to call when a listener has been connected.
+   * @param arg user-supplied argument (tcp_pcb.callback_arg)
+   * @param pcb a new tcp_pcb that now is connected
+   * @param err an error argument (TODO: that is current always ERR_OK?)
+   * @return ERR_OK: accept the new connection,
+   *                 any other err_t abortsthe new connection
+   */
+#define DEF_ACCEPT_CALLBACK  tcp_accept_fn accept;
+#else /* LWIP_CALLBACK_API */
+#define DEF_ACCEPT_CALLBACK
+#endif /* LWIP_CALLBACK_API */
+
+/**
+ * members common to struct tcp_pcb and struct tcp_listen_pcb
+ */
+#define TCP_PCB_COMMON(type) \
+  type *next; /* for the linked list */ \
+  enum tcp_state state; /* TCP state */ \
+  u8_t prio; \
+  void *callback_arg; \
+  /* the accept callback for listen- and normal pcbs, if LWIP_CALLBACK_API */ \
+  DEF_ACCEPT_CALLBACK \
+  /* ports are in host byte order */ \
+  u16_t local_port
+
+
+/* the TCP protocol control block */
+struct tcp_pcb {
+/** common PCB members */
+  IP_PCB;
+/** protocol specific PCB members */
+  TCP_PCB_COMMON(struct tcp_pcb);
+
+  /* ports are in host byte order */
+  u16_t remote_port;
+  
+  u8_t flags;
+#define TF_ACK_DELAY   ((u8_t)0x01U)   /* Delayed ACK. */
+#define TF_ACK_NOW     ((u8_t)0x02U)   /* Immediate ACK. */
+#define TF_INFR        ((u8_t)0x04U)   /* In fast recovery. */
+#define TF_TIMESTAMP   ((u8_t)0x08U)   /* Timestamp option enabled */
+#define TF_RXCLOSED    ((u8_t)0x10U)   /* rx closed by tcp_shutdown */
+#define TF_FIN         ((u8_t)0x20U)   /* Connection was closed locally (FIN segment enqueued). */
+#define TF_NODELAY     ((u8_t)0x40U)   /* Disable Nagle algorithm */
+#define TF_NAGLEMEMERR ((u8_t)0x80U)   /* nagle enabled, memerr, try to output to prevent delayed ACK to happen */
+
+  /* the rest of the fields are in host byte order
+     as we have to do some math with them */
+  /* receiver variables */
+  u32_t rcv_nxt;   /* next seqno expected */
+  u16_t rcv_wnd;   /* receiver window available */
+  u16_t rcv_ann_wnd; /* receiver window to announce */
+  u32_t rcv_ann_right_edge; /* announced right edge of window */
+
+  /* Timers */
+  u32_t tmr;
+  u8_t polltmr, pollinterval;
+  
+  /* Retransmission timer. */
+  s16_t rtime;
+  
+  u16_t mss;   /* maximum segment size */
+  
+  /* RTT (round trip time) estimation variables */
+  u32_t rttest; /* RTT estimate in 500ms ticks */
+  u32_t rtseq;  /* sequence number being timed */
+  s16_t sa, sv; /* @todo document this */
+
+  s16_t rto;    /* retransmission time-out */
+  u8_t nrtx;    /* number of retransmissions */
+
+  /* fast retransmit/recovery */
+  u32_t lastack; /* Highest acknowledged seqno. */
+  u8_t dupacks;
+  
+  /* congestion avoidance/control variables */
+  u16_t cwnd;  
+  u16_t ssthresh;
+
+  /* sender variables */
+  u32_t snd_nxt;   /* next new seqno to be sent */
+  u16_t snd_wnd;   /* sender window */
+  u32_t snd_wl1, snd_wl2; /* Sequence and acknowledgement numbers of last
+                             window update. */
+  u32_t snd_lbb;       /* Sequence number of next byte to be buffered. */
+
+  u16_t acked;
+  
+  u16_t snd_buf;   /* Available buffer space for sending (in bytes). */
+#define TCP_SNDQUEUELEN_OVERFLOW (0xffffU-3)
+  u16_t snd_queuelen; /* Available buffer space for sending (in tcp_segs). */
+
+#if TCP_OVERSIZE
+  /* Extra bytes available at the end of the last pbuf in unsent. */
+  u16_t unsent_oversize;
+#endif /* TCP_OVERSIZE */ 
+
+  /* These are ordered by sequence number: */
+  struct tcp_seg *unsent;   /* Unsent (queued) segments. */
+  struct tcp_seg *unacked;  /* Sent but unacknowledged segments. */
+#if TCP_QUEUE_OOSEQ  
+  struct tcp_seg *ooseq;    /* Received out of sequence segments. */
+#endif /* TCP_QUEUE_OOSEQ */
+
+  struct pbuf *refused_data; /* Data previously received but not yet taken by upper layer */
+
+#if LWIP_CALLBACK_API
+  /* Function to be called when more send buffer space is available. */
+  tcp_sent_fn sent;
+  /* Function to be called when (in-sequence) data has arrived. */
+  tcp_recv_fn recv;
+  /* Function to be called when a connection has been set up. */
+  tcp_connected_fn connected;
+  /* Function which is called periodically. */
+  tcp_poll_fn poll;
+  /* Function to be called whenever a fatal error occurs. */
+  tcp_err_fn errf;
+#endif /* LWIP_CALLBACK_API */
+
+#if LWIP_TCP_TIMESTAMPS
+  u32_t ts_lastacksent;
+  u32_t ts_recent;
+#endif /* LWIP_TCP_TIMESTAMPS */
+
+  /* idle time before KEEPALIVE is sent */
+  u32_t keep_idle;
+#if LWIP_TCP_KEEPALIVE
+  u32_t keep_intvl;
+  u32_t keep_cnt;
+#endif /* LWIP_TCP_KEEPALIVE */
+  
+  /* Persist timer counter */
+  u32_t persist_cnt;
+  /* Persist timer back-off */
+  u8_t persist_backoff;
+
+  /* KEEPALIVE counter */
+  u8_t keep_cnt_sent;
+};
+
+struct tcp_pcb_listen {  
+/* Common members of all PCB types */
+  IP_PCB;
+/* Protocol specific PCB members */
+  TCP_PCB_COMMON(struct tcp_pcb_listen);
+
+#if TCP_LISTEN_BACKLOG
+  u8_t backlog;
+  u8_t accepts_pending;
+#endif /* TCP_LISTEN_BACKLOG */
+};
+
+#if LWIP_EVENT_API
+
+enum lwip_event {
+  LWIP_EVENT_ACCEPT,
+  LWIP_EVENT_SENT,
+  LWIP_EVENT_RECV,
+  LWIP_EVENT_CONNECTED,
+  LWIP_EVENT_POLL,
+  LWIP_EVENT_ERR
+};
+
+err_t lwip_tcp_event(void *arg, struct tcp_pcb *pcb,
+         enum lwip_event,
+         struct pbuf *p,
+         u16_t size,
+         err_t err);
+
+#endif /* LWIP_EVENT_API */
+
+/* Application program's interface: */
+struct tcp_pcb * tcp_new     (void);
+
+void             tcp_arg     (struct tcp_pcb *pcb, void *arg);
+void             tcp_accept  (struct tcp_pcb *pcb, tcp_accept_fn accept);
+void             tcp_recv    (struct tcp_pcb *pcb, tcp_recv_fn recv);
+void             tcp_sent    (struct tcp_pcb *pcb, tcp_sent_fn sent);
+void             tcp_poll    (struct tcp_pcb *pcb, tcp_poll_fn poll, u8_t interval);
+void             tcp_err     (struct tcp_pcb *pcb, tcp_err_fn err);
+
+#define          tcp_mss(pcb)             (((pcb)->flags & TF_TIMESTAMP) ? ((pcb)->mss - 12)  : (pcb)->mss)
+#define          tcp_sndbuf(pcb)          ((pcb)->snd_buf)
+#define          tcp_sndqueuelen(pcb)     ((pcb)->snd_queuelen)
+#define          tcp_nagle_disable(pcb)   ((pcb)->flags |= TF_NODELAY)
+#define          tcp_nagle_enable(pcb)    ((pcb)->flags &= ~TF_NODELAY)
+#define          tcp_nagle_disabled(pcb)  (((pcb)->flags & TF_NODELAY) != 0)
+
+#if TCP_LISTEN_BACKLOG
+#define          tcp_accepted(pcb) do { \
+  LWIP_ASSERT("pcb->state == LISTEN (called for wrong pcb?)", pcb->state == LISTEN); \
+  (((struct tcp_pcb_listen *)(pcb))->accepts_pending--); } while(0)
+#else  /* TCP_LISTEN_BACKLOG */
+#define          tcp_accepted(pcb) LWIP_ASSERT("pcb->state == LISTEN (called for wrong pcb?)", \
+                                               pcb->state == LISTEN)
+#endif /* TCP_LISTEN_BACKLOG */
+
+void             tcp_recved  (struct tcp_pcb *pcb, u16_t len);
+err_t            tcp_bind    (struct tcp_pcb *pcb, ip_addr_t *ipaddr,
+                              u16_t port);
+err_t            tcp_connect (struct tcp_pcb *pcb, ip_addr_t *ipaddr,
+                              u16_t port, tcp_connected_fn connected);
+
+struct tcp_pcb * tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog);
+#define          tcp_listen(pcb) tcp_listen_with_backlog(pcb, TCP_DEFAULT_LISTEN_BACKLOG)
+
+void             tcp_abort (struct tcp_pcb *pcb);
+err_t            tcp_close   (struct tcp_pcb *pcb);
+err_t            tcp_shutdown(struct tcp_pcb *pcb, int shut_rx, int shut_tx);
+
+/* Flags for "apiflags" parameter in tcp_write */
+#define TCP_WRITE_FLAG_COPY 0x01
+#define TCP_WRITE_FLAG_MORE 0x02
+
+err_t            tcp_write   (struct tcp_pcb *pcb, const void *dataptr, u16_t len,
+                              u8_t apiflags);
+
+void             tcp_setprio (struct tcp_pcb *pcb, u8_t prio);
+
+#define TCP_PRIO_MIN    1
+#define TCP_PRIO_NORMAL 64
+#define TCP_PRIO_MAX    127
+
+err_t            tcp_output  (struct tcp_pcb *pcb);
+
+
+const char* tcp_debug_state_str(enum tcp_state s);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_TCP */
+
+#endif /* __LWIP_TCP_H__ */
diff --git a/core/lwip/src/include/lwip/tcp_impl.h b/core/lwip/src/include/lwip/tcp_impl.h
new file mode 100644
index 00000000..b4feec0d
--- /dev/null
+++ b/core/lwip/src/include/lwip/tcp_impl.h
@@ -0,0 +1,471 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_TCP_IMPL_H__
+#define __LWIP_TCP_IMPL_H__
+
+#include "lwip/opt.h"
+
+#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/tcp.h"
+#include "lwip/sys.h"
+#include "lwip/mem.h"
+#include "lwip/pbuf.h"
+#include "lwip/ip.h"
+#include "lwip/icmp.h"
+#include "lwip/err.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Functions for interfacing with TCP: */
+
+/* Lower layer interface to TCP: */
+#define tcp_init() /* Compatibility define, no init needed. */
+void             tcp_tmr     (void);  /* Must be called every
+                                         TCP_TMR_INTERVAL
+                                         ms. (Typically 250 ms). */
+/* It is also possible to call these two functions at the right
+   intervals (instead of calling tcp_tmr()). */
+void             tcp_slowtmr (void);
+void             tcp_fasttmr (void);
+
+
+/* Only used by IP to pass a TCP segment to TCP: */
+void             tcp_input   (struct pbuf *p, struct netif *inp);
+/* Used within the TCP code only: */
+struct tcp_pcb * tcp_alloc   (u8_t prio);
+void             tcp_abandon (struct tcp_pcb *pcb, int reset);
+err_t            tcp_send_empty_ack(struct tcp_pcb *pcb);
+void             tcp_rexmit  (struct tcp_pcb *pcb);
+void             tcp_rexmit_rto  (struct tcp_pcb *pcb);
+void             tcp_rexmit_fast (struct tcp_pcb *pcb);
+u32_t            tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb);
+
+/**
+ * This is the Nagle algorithm: try to combine user data to send as few TCP
+ * segments as possible. Only send if
+ * - no previously transmitted data on the connection remains unacknowledged or
+ * - the TF_NODELAY flag is set (nagle algorithm turned off for this pcb) or
+ * - the only unsent segment is at least pcb->mss bytes long (or there is more
+ *   than one unsent segment - with lwIP, this can happen although unsent->len < mss)
+ * - or if we are in fast-retransmit (TF_INFR)
+ */
+#define tcp_do_output_nagle(tpcb) ((((tpcb)->unacked == NULL) || \
+                            ((tpcb)->flags & (TF_NODELAY | TF_INFR)) || \
+                            (((tpcb)->unsent != NULL) && (((tpcb)->unsent->next != NULL) || \
+                              ((tpcb)->unsent->len >= (tpcb)->mss))) \
+                            ) ? 1 : 0)
+#define tcp_output_nagle(tpcb) (tcp_do_output_nagle(tpcb) ? tcp_output(tpcb) : ERR_OK)
+
+
+#define TCP_SEQ_LT(a,b)     ((s32_t)((a)-(b)) < 0)
+#define TCP_SEQ_LEQ(a,b)    ((s32_t)((a)-(b)) <= 0)
+#define TCP_SEQ_GT(a,b)     ((s32_t)((a)-(b)) > 0)
+#define TCP_SEQ_GEQ(a,b)    ((s32_t)((a)-(b)) >= 0)
+/* is b<=a<=c? */
+#if 0 /* see bug #10548 */
+#define TCP_SEQ_BETWEEN(a,b,c) ((c)-(b) >= (a)-(b))
+#endif
+#define TCP_SEQ_BETWEEN(a,b,c) (TCP_SEQ_GEQ(a,b) && TCP_SEQ_LEQ(a,c))
+#define TCP_FIN 0x01U
+#define TCP_SYN 0x02U
+#define TCP_RST 0x04U
+#define TCP_PSH 0x08U
+#define TCP_ACK 0x10U
+#define TCP_URG 0x20U
+#define TCP_ECE 0x40U
+#define TCP_CWR 0x80U
+
+#define TCP_FLAGS 0x3fU
+
+/* Length of the TCP header, excluding options. */
+#define TCP_HLEN 20
+
+#ifndef TCP_TMR_INTERVAL
+#define TCP_TMR_INTERVAL       250  /* The TCP timer interval in milliseconds. */
+#endif /* TCP_TMR_INTERVAL */
+
+#ifndef TCP_FAST_INTERVAL
+#define TCP_FAST_INTERVAL      TCP_TMR_INTERVAL /* the fine grained timeout in milliseconds */
+#endif /* TCP_FAST_INTERVAL */
+
+#ifndef TCP_SLOW_INTERVAL
+#define TCP_SLOW_INTERVAL      (2*TCP_TMR_INTERVAL)  /* the coarse grained timeout in milliseconds */
+#endif /* TCP_SLOW_INTERVAL */
+
+#define TCP_FIN_WAIT_TIMEOUT 20000 /* milliseconds */
+#define TCP_SYN_RCVD_TIMEOUT 20000 /* milliseconds */
+
+#define TCP_OOSEQ_TIMEOUT        6U /* x RTO */
+
+#ifndef TCP_MSL
+#define TCP_MSL 60000UL /* The maximum segment lifetime in milliseconds */
+#endif
+
+/* Keepalive values, compliant with RFC 1122. Don't change this unless you know what you're doing */
+#ifndef  TCP_KEEPIDLE_DEFAULT
+#define  TCP_KEEPIDLE_DEFAULT     7200000UL /* Default KEEPALIVE timer in milliseconds */
+#endif
+
+#ifndef  TCP_KEEPINTVL_DEFAULT
+#define  TCP_KEEPINTVL_DEFAULT    75000UL   /* Default Time between KEEPALIVE probes in milliseconds */
+#endif
+
+#ifndef  TCP_KEEPCNT_DEFAULT
+#define  TCP_KEEPCNT_DEFAULT      9U        /* Default Counter for KEEPALIVE probes */
+#endif
+
+#define  TCP_MAXIDLE              TCP_KEEPCNT_DEFAULT * TCP_KEEPINTVL_DEFAULT  /* Maximum KEEPALIVE probe time */
+
+/* Fields are (of course) in network byte order.
+ * Some fields are converted to host byte order in tcp_input().
+ */
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct tcp_hdr {
+  PACK_STRUCT_FIELD(u16_t src);
+  PACK_STRUCT_FIELD(u16_t dest);
+  PACK_STRUCT_FIELD(u32_t seqno);
+  PACK_STRUCT_FIELD(u32_t ackno);
+  PACK_STRUCT_FIELD(u16_t _hdrlen_rsvd_flags);
+  PACK_STRUCT_FIELD(u16_t wnd);
+  PACK_STRUCT_FIELD(u16_t chksum);
+  PACK_STRUCT_FIELD(u16_t urgp);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+#define TCPH_OFFSET(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 8)
+#define TCPH_HDRLEN(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 12)
+#define TCPH_FLAGS(phdr)  (ntohs((phdr)->_hdrlen_rsvd_flags) & TCP_FLAGS)
+
+#define TCPH_OFFSET_SET(phdr, offset) (phdr)->_hdrlen_rsvd_flags = htons(((offset) << 8) | TCPH_FLAGS(phdr))
+#define TCPH_HDRLEN_SET(phdr, len) (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | TCPH_FLAGS(phdr))
+#define TCPH_FLAGS_SET(phdr, flags) (phdr)->_hdrlen_rsvd_flags = (((phdr)->_hdrlen_rsvd_flags & PP_HTONS((u16_t)(~(u16_t)(TCP_FLAGS)))) | htons(flags))
+#define TCPH_HDRLEN_FLAGS_SET(phdr, len, flags) (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | (flags))
+
+#define TCPH_SET_FLAG(phdr, flags ) (phdr)->_hdrlen_rsvd_flags = ((phdr)->_hdrlen_rsvd_flags | htons(flags))
+#define TCPH_UNSET_FLAG(phdr, flags) (phdr)->_hdrlen_rsvd_flags = htons(ntohs((phdr)->_hdrlen_rsvd_flags) | (TCPH_FLAGS(phdr) & ~(flags)) )
+
+#define TCP_TCPLEN(seg) ((seg)->len + ((TCPH_FLAGS((seg)->tcphdr) & (TCP_FIN | TCP_SYN)) != 0))
+
+/** Flags used on input processing, not on pcb->flags
+*/
+#define TF_RESET     (u8_t)0x08U   /* Connection was reset. */
+#define TF_CLOSED    (u8_t)0x10U   /* Connection was sucessfully closed. */
+#define TF_GOT_FIN   (u8_t)0x20U   /* Connection was closed by the remote end. */
+
+
+#if LWIP_EVENT_API
+
+#define TCP_EVENT_ACCEPT(pcb,err,ret)    ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
+                LWIP_EVENT_ACCEPT, NULL, 0, err)
+#define TCP_EVENT_SENT(pcb,space,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
+                   LWIP_EVENT_SENT, NULL, space, ERR_OK)
+#define TCP_EVENT_RECV(pcb,p,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
+                LWIP_EVENT_RECV, (p), 0, (err))
+#define TCP_EVENT_CLOSED(pcb,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
+                LWIP_EVENT_RECV, NULL, 0, ERR_OK)
+#define TCP_EVENT_CONNECTED(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
+                LWIP_EVENT_CONNECTED, NULL, 0, (err))
+#define TCP_EVENT_POLL(pcb,ret)       ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
+                LWIP_EVENT_POLL, NULL, 0, ERR_OK)
+#define TCP_EVENT_ERR(errf,arg,err)  lwip_tcp_event((arg), NULL, \
+                LWIP_EVENT_ERR, NULL, 0, (err))
+
+#else /* LWIP_EVENT_API */
+
+#define TCP_EVENT_ACCEPT(pcb,err,ret)                          \
+  do {                                                         \
+    if((pcb)->accept != NULL)                                  \
+      (ret) = (pcb)->accept((pcb)->callback_arg,(pcb),(err));  \
+    else (ret) = ERR_ARG;                                      \
+  } while (0)
+
+#define TCP_EVENT_SENT(pcb,space,ret)                          \
+  do {                                                         \
+    if((pcb)->sent != NULL)                                    \
+      (ret) = (pcb)->sent((pcb)->callback_arg,(pcb),(space));  \
+    else (ret) = ERR_OK;                                       \
+  } while (0)
+
+#define TCP_EVENT_RECV(pcb,p,err,ret)                          \
+  do {                                                         \
+    if((pcb)->recv != NULL) {                                  \
+      (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),(p),(err));\
+    } else {                                                   \
+      (ret) = tcp_recv_null(NULL, (pcb), (p), (err));          \
+    }                                                          \
+  } while (0)
+
+#define TCP_EVENT_CLOSED(pcb,ret)                                \
+  do {                                                           \
+    if(((pcb)->recv != NULL)) {                                  \
+      (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),NULL,ERR_OK);\
+    } else {                                                     \
+      (ret) = ERR_OK;                                            \
+    }                                                            \
+  } while (0)
+
+#define TCP_EVENT_CONNECTED(pcb,err,ret)                         \
+  do {                                                           \
+    if((pcb)->connected != NULL)                                 \
+      (ret) = (pcb)->connected((pcb)->callback_arg,(pcb),(err)); \
+    else (ret) = ERR_OK;                                         \
+  } while (0)
+
+#define TCP_EVENT_POLL(pcb,ret)                                \
+  do {                                                         \
+    if((pcb)->poll != NULL)                                    \
+      (ret) = (pcb)->poll((pcb)->callback_arg,(pcb));          \
+    else (ret) = ERR_OK;                                       \
+  } while (0)
+
+#define TCP_EVENT_ERR(errf,arg,err)                            \
+  do {                                                         \
+    if((errf) != NULL)                                         \
+      (errf)((arg),(err));                                     \
+  } while (0)
+
+#endif /* LWIP_EVENT_API */
+
+/** Enabled extra-check for TCP_OVERSIZE if LWIP_DEBUG is enabled */
+#if TCP_OVERSIZE && defined(LWIP_DEBUG)
+#define TCP_OVERSIZE_DBGCHECK 1
+#else
+#define TCP_OVERSIZE_DBGCHECK 0
+#endif
+
+/** Don't generate checksum on copy if CHECKSUM_GEN_TCP is disabled */
+#define TCP_CHECKSUM_ON_COPY  (LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_TCP)
+
+/* This structure represents a TCP segment on the unsent, unacked and ooseq queues */
+struct tcp_seg {
+  struct tcp_seg *next;    /* used when putting segements on a queue */
+  struct pbuf *p;          /* buffer containing data + TCP header */
+  u16_t len;               /* the TCP length of this segment */
+#if TCP_OVERSIZE_DBGCHECK
+  u16_t oversize_left;     /* Extra bytes available at the end of the last
+                              pbuf in unsent (used for asserting vs.
+                              tcp_pcb.unsent_oversized only) */
+#endif /* TCP_OVERSIZE_DBGCHECK */ 
+#if TCP_CHECKSUM_ON_COPY
+  u16_t chksum;
+  u8_t  chksum_swapped;
+#endif /* TCP_CHECKSUM_ON_COPY */
+  u8_t  flags;
+#define TF_SEG_OPTS_MSS         (u8_t)0x01U /* Include MSS option. */
+#define TF_SEG_OPTS_TS          (u8_t)0x02U /* Include timestamp option. */
+#define TF_SEG_DATA_CHECKSUMMED (u8_t)0x04U /* ALL data (not the header) is
+                                               checksummed into 'chksum' */
+  struct tcp_hdr *tcphdr;  /* the TCP header */
+};
+
+#define LWIP_TCP_OPT_LENGTH(flags)              \
+  (flags & TF_SEG_OPTS_MSS ? 4  : 0) +          \
+  (flags & TF_SEG_OPTS_TS  ? 12 : 0)
+
+/** This returns a TCP header option for MSS in an u32_t */
+#define TCP_BUILD_MSS_OPTION(x) (x) = PP_HTONL(((u32_t)2 << 24) |          \
+                                               ((u32_t)4 << 16) |          \
+                                               (((u32_t)TCP_MSS / 256) << 8) | \
+                                               (TCP_MSS & 255))
+
+/* Global variables: */
+extern struct tcp_pcb *tcp_input_pcb;
+extern u32_t tcp_ticks;
+
+/* The TCP PCB lists. */
+union tcp_listen_pcbs_t { /* List of all TCP PCBs in LISTEN state. */
+  struct tcp_pcb_listen *listen_pcbs; 
+  struct tcp_pcb *pcbs;
+};
+extern struct tcp_pcb *tcp_bound_pcbs;
+extern union tcp_listen_pcbs_t tcp_listen_pcbs;
+extern struct tcp_pcb *tcp_active_pcbs;  /* List of all TCP PCBs that are in a
+              state in which they accept or send
+              data. */
+extern struct tcp_pcb *tcp_tw_pcbs;      /* List of all TCP PCBs in TIME-WAIT. */
+
+extern struct tcp_pcb *tcp_tmp_pcb;      /* Only used for temporary storage. */
+
+/* Axioms about the above lists:   
+   1) Every TCP PCB that is not CLOSED is in one of the lists.
+   2) A PCB is only in one of the lists.
+   3) All PCBs in the tcp_listen_pcbs list is in LISTEN state.
+   4) All PCBs in the tcp_tw_pcbs list is in TIME-WAIT state.
+*/
+/* Define two macros, TCP_REG and TCP_RMV that registers a TCP PCB
+   with a PCB list or removes a PCB from a list, respectively. */
+#ifndef TCP_DEBUG_PCB_LISTS
+#define TCP_DEBUG_PCB_LISTS 0
+#endif
+#if TCP_DEBUG_PCB_LISTS
+#define TCP_REG(pcbs, npcb) do {\
+                            LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %d\n", (npcb), (npcb)->local_port)); \
+                            for(tcp_tmp_pcb = *(pcbs); \
+          tcp_tmp_pcb != NULL; \
+        tcp_tmp_pcb = tcp_tmp_pcb->next) { \
+                                LWIP_ASSERT("TCP_REG: already registered\n", tcp_tmp_pcb != (npcb)); \
+                            } \
+                            LWIP_ASSERT("TCP_REG: pcb->state != CLOSED", ((pcbs) == &tcp_bound_pcbs) || ((npcb)->state != CLOSED)); \
+                            (npcb)->next = *(pcbs); \
+                            LWIP_ASSERT("TCP_REG: npcb->next != npcb", (npcb)->next != (npcb)); \
+                            *(pcbs) = (npcb); \
+                            LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
+              tcp_timer_needed(); \
+                            } while(0)
+#define TCP_RMV(pcbs, npcb) do { \
+                            LWIP_ASSERT("TCP_RMV: pcbs != NULL", *(pcbs) != NULL); \
+                            LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removing %p from %p\n", (npcb), *(pcbs))); \
+                            if(*(pcbs) == (npcb)) { \
+                               *(pcbs) = (*pcbs)->next; \
+                            } else for(tcp_tmp_pcb = *(pcbs); tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \
+                               if(tcp_tmp_pcb->next == (npcb)) { \
+                                  tcp_tmp_pcb->next = (npcb)->next; \
+                                  break; \
+                               } \
+                            } \
+                            (npcb)->next = NULL; \
+                            LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
+                            LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removed %p from %p\n", (npcb), *(pcbs))); \
+                            } while(0)
+
+#else /* LWIP_DEBUG */
+
+#define TCP_REG(pcbs, npcb)                        \
+  do {                                             \
+    (npcb)->next = *pcbs;                          \
+    *(pcbs) = (npcb);                              \
+    tcp_timer_needed();                            \
+  } while (0)
+
+#define TCP_RMV(pcbs, npcb)                        \
+  do {                                             \
+    if(*(pcbs) == (npcb)) {                        \
+      (*(pcbs)) = (*pcbs)->next;                   \
+    }                                              \
+    else {                                         \
+      for(tcp_tmp_pcb = *pcbs;                     \
+          tcp_tmp_pcb != NULL;                     \
+          tcp_tmp_pcb = tcp_tmp_pcb->next) {       \
+        if(tcp_tmp_pcb->next == (npcb)) {          \
+          tcp_tmp_pcb->next = (npcb)->next;        \
+          break;                                   \
+        }                                          \
+      }                                            \
+    }                                              \
+    (npcb)->next = NULL;                           \
+  } while(0)
+
+#endif /* LWIP_DEBUG */
+
+
+/* Internal functions: */
+struct tcp_pcb *tcp_pcb_copy(struct tcp_pcb *pcb);
+void tcp_pcb_purge(struct tcp_pcb *pcb);
+void tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb);
+
+void tcp_segs_free(struct tcp_seg *seg);
+void tcp_seg_free(struct tcp_seg *seg);
+struct tcp_seg *tcp_seg_copy(struct tcp_seg *seg);
+
+#define tcp_ack(pcb)                               \
+  do {                                             \
+    if((pcb)->flags & TF_ACK_DELAY) {              \
+      (pcb)->flags &= ~TF_ACK_DELAY;               \
+      (pcb)->flags |= TF_ACK_NOW;                  \
+    }                                              \
+    else {                                         \
+      (pcb)->flags |= TF_ACK_DELAY;                \
+    }                                              \
+  } while (0)
+
+#define tcp_ack_now(pcb)                           \
+  do {                                             \
+    (pcb)->flags |= TF_ACK_NOW;                    \
+  } while (0)
+
+err_t tcp_send_fin(struct tcp_pcb *pcb);
+err_t tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags);
+
+void tcp_rexmit_seg(struct tcp_pcb *pcb, struct tcp_seg *seg);
+
+void tcp_rst(u32_t seqno, u32_t ackno,
+       ip_addr_t *local_ip, ip_addr_t *remote_ip,
+       u16_t local_port, u16_t remote_port);
+
+u32_t tcp_next_iss(void);
+
+void tcp_keepalive(struct tcp_pcb *pcb);
+void tcp_zero_window_probe(struct tcp_pcb *pcb);
+
+#if TCP_CALCULATE_EFF_SEND_MSS
+u16_t tcp_eff_send_mss(u16_t sendmss, ip_addr_t *addr);
+#endif /* TCP_CALCULATE_EFF_SEND_MSS */
+
+#if LWIP_CALLBACK_API
+err_t tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);
+#endif /* LWIP_CALLBACK_API */
+
+#if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
+void tcp_debug_print(struct tcp_hdr *tcphdr);
+void tcp_debug_print_flags(u8_t flags);
+void tcp_debug_print_state(enum tcp_state s);
+void tcp_debug_print_pcbs(void);
+s16_t tcp_pcbs_sane(void);
+#else
+#  define tcp_debug_print(tcphdr)
+#  define tcp_debug_print_flags(flags)
+#  define tcp_debug_print_state(s)
+#  define tcp_debug_print_pcbs()
+#  define tcp_pcbs_sane() 1
+#endif /* TCP_DEBUG */
+
+/** External function (implemented in timers.c), called when TCP detects
+ * that a timer is needed (i.e. active- or time-wait-pcb found). */
+void tcp_timer_needed(void);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_TCP */
+
+#endif /* __LWIP_TCP_H__ */
diff --git a/core/lwip/src/include/lwip/tcpip.h b/core/lwip/src/include/lwip/tcpip.h
new file mode 100644
index 00000000..995ba8ad
--- /dev/null
+++ b/core/lwip/src/include/lwip/tcpip.h
@@ -0,0 +1,159 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_TCPIP_H__
+#define __LWIP_TCPIP_H__
+
+#include "lwip/opt.h"
+
+#if !NO_SYS /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/api_msg.h"
+#include "lwip/netifapi.h"
+#include "lwip/pbuf.h"
+#include "lwip/api.h"
+#include "lwip/sys.h"
+#include "lwip/timers.h"
+#include "lwip/netif.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** Define this to something that triggers a watchdog. This is called from
+ * tcpip_thread after processing a message. */
+#ifndef LWIP_TCPIP_THREAD_ALIVE
+#define LWIP_TCPIP_THREAD_ALIVE()
+#endif
+
+#if LWIP_TCPIP_CORE_LOCKING
+/** The global semaphore to lock the stack. */
+extern sys_mutex_t lock_tcpip_core;
+#define LOCK_TCPIP_CORE()     sys_mutex_lock(&lock_tcpip_core)
+#define UNLOCK_TCPIP_CORE()   sys_mutex_unlock(&lock_tcpip_core)
+#define TCPIP_APIMSG(m)       tcpip_apimsg_lock(m)
+#define TCPIP_APIMSG_ACK(m)
+#define TCPIP_NETIFAPI(m)     tcpip_netifapi_lock(m)
+#define TCPIP_NETIFAPI_ACK(m)
+#else /* LWIP_TCPIP_CORE_LOCKING */
+#define LOCK_TCPIP_CORE()
+#define UNLOCK_TCPIP_CORE()
+#define TCPIP_APIMSG(m)       tcpip_apimsg(m)
+#define TCPIP_APIMSG_ACK(m)   sys_sem_signal(&m->conn->op_completed)
+#define TCPIP_NETIFAPI(m)     tcpip_netifapi(m)
+#define TCPIP_NETIFAPI_ACK(m) sys_sem_signal(&m->sem)
+#endif /* LWIP_TCPIP_CORE_LOCKING */
+
+/** Function prototype for the init_done function passed to tcpip_init */
+typedef void (*tcpip_init_done_fn)(void *arg);
+/** Function prototype for functions passed to tcpip_callback() */
+typedef void (*tcpip_callback_fn)(void *ctx);
+
+void tcpip_init(tcpip_init_done_fn tcpip_init_done, void *arg);
+
+#if LWIP_NETCONN
+err_t tcpip_apimsg(struct api_msg *apimsg);
+#if LWIP_TCPIP_CORE_LOCKING
+err_t tcpip_apimsg_lock(struct api_msg *apimsg);
+#endif /* LWIP_TCPIP_CORE_LOCKING */
+#endif /* LWIP_NETCONN */
+
+err_t tcpip_input(struct pbuf *p, struct netif *inp);
+
+#if LWIP_NETIF_API
+err_t tcpip_netifapi(struct netifapi_msg *netifapimsg);
+#if LWIP_TCPIP_CORE_LOCKING
+err_t tcpip_netifapi_lock(struct netifapi_msg *netifapimsg);
+#endif /* LWIP_TCPIP_CORE_LOCKING */
+#endif /* LWIP_NETIF_API */
+
+err_t tcpip_callback_with_block(tcpip_callback_fn function, void *ctx, u8_t block);
+#define tcpip_callback(f, ctx)              tcpip_callback_with_block(f, ctx, 1)
+
+/* free pbufs or heap memory from another context without blocking */
+err_t pbuf_free_callback(struct pbuf *p);
+err_t mem_free_callback(void *m);
+
+#if LWIP_TCPIP_TIMEOUT
+err_t tcpip_timeout(u32_t msecs, sys_timeout_handler h, void *arg);
+err_t tcpip_untimeout(sys_timeout_handler h, void *arg);
+#endif /* LWIP_TCPIP_TIMEOUT */
+
+enum tcpip_msg_type {
+#if LWIP_NETCONN
+  TCPIP_MSG_API,
+#endif /* LWIP_NETCONN */
+  TCPIP_MSG_INPKT,
+#if LWIP_NETIF_API
+  TCPIP_MSG_NETIFAPI,
+#endif /* LWIP_NETIF_API */
+#if LWIP_TCPIP_TIMEOUT
+  TCPIP_MSG_TIMEOUT,
+  TCPIP_MSG_UNTIMEOUT,
+#endif /* LWIP_TCPIP_TIMEOUT */
+  TCPIP_MSG_CALLBACK
+};
+
+struct tcpip_msg {
+  enum tcpip_msg_type type;
+  sys_sem_t *sem;
+  union {
+#if LWIP_NETCONN
+    struct api_msg *apimsg;
+#endif /* LWIP_NETCONN */
+#if LWIP_NETIF_API
+    struct netifapi_msg *netifapimsg;
+#endif /* LWIP_NETIF_API */
+    struct {
+      struct pbuf *p;
+      struct netif *netif;
+    } inp;
+    struct {
+      tcpip_callback_fn function;
+      void *ctx;
+    } cb;
+#if LWIP_TCPIP_TIMEOUT
+    struct {
+      u32_t msecs;
+      sys_timeout_handler h;
+      void *arg;
+    } tmo;
+#endif /* LWIP_TCPIP_TIMEOUT */
+  } msg;
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* !NO_SYS */
+
+#endif /* __LWIP_TCPIP_H__ */
diff --git a/core/lwip/src/include/lwip/timers.h b/core/lwip/src/include/lwip/timers.h
new file mode 100644
index 00000000..fb92b4b4
--- /dev/null
+++ b/core/lwip/src/include/lwip/timers.h
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *         Simon Goldschmidt
+ *
+ */
+#ifndef __LWIP_TIMERS_H__
+#define __LWIP_TIMERS_H__
+
+#include "lwip/opt.h"
+
+/* Timers are not supported when NO_SYS==1 and NO_SYS_NO_TIMERS==1 */
+#define LWIP_TIMERS (!NO_SYS || (NO_SYS && !NO_SYS_NO_TIMERS))
+
+#if LWIP_TIMERS
+
+#include "lwip/err.h"
+#include "lwip/sys.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef LWIP_DEBUG_TIMERNAMES
+#ifdef LWIP_DEBUG
+#define LWIP_DEBUG_TIMERNAMES SYS_DEBUG
+#else /* LWIP_DEBUG */
+#define LWIP_DEBUG_TIMERNAMES 0
+#endif /* LWIP_DEBUG*/
+#endif
+
+/** Function prototype for a timeout callback function. Register such a function
+ * using sys_timeout().
+ *
+ * @param arg Additional argument to pass to the function - set up by sys_timeout()
+ */
+typedef void (* sys_timeout_handler)(void *arg);
+
+struct sys_timeo {
+  struct sys_timeo *next;
+  u32_t time;
+  sys_timeout_handler h;
+  void *arg;
+#if LWIP_DEBUG_TIMERNAMES
+  const char* handler_name;
+#endif /* LWIP_DEBUG_TIMERNAMES */
+};
+
+void sys_timeouts_init(void);
+
+#if LWIP_DEBUG_TIMERNAMES
+void sys_timeout_debug(u32_t msecs, sys_timeout_handler handler, void *arg, const char* handler_name);
+#define sys_timeout(msecs, handler, arg) sys_timeout_debug(msecs, handler, arg, #handler)
+#else /* LWIP_DEBUG_TIMERNAMES */
+void sys_timeout(u32_t msecs, sys_timeout_handler handler, void *arg);
+#endif /* LWIP_DEBUG_TIMERNAMES */
+
+void sys_untimeout(sys_timeout_handler handler, void *arg);
+#if NO_SYS
+void sys_check_timeouts(void);
+void sys_restart_timeouts(void);
+#else /* NO_SYS */
+void sys_timeouts_mbox_fetch(sys_mbox_t *mbox, void **msg);
+#endif /* NO_SYS */
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_TIMERS */
+#endif /* __LWIP_TIMERS_H__ */
diff --git a/core/lwip/src/include/lwip/udp.h b/core/lwip/src/include/lwip/udp.h
new file mode 100644
index 00000000..c98c1b3e
--- /dev/null
+++ b/core/lwip/src/include/lwip/udp.h
@@ -0,0 +1,171 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __LWIP_UDP_H__
+#define __LWIP_UDP_H__
+
+#include "lwip/opt.h"
+
+#if LWIP_UDP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/pbuf.h"
+#include "lwip/netif.h"
+#include "lwip/ip_addr.h"
+#include "lwip/ip.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define UDP_HLEN 8
+
+/* Fields are (of course) in network byte order. */
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct udp_hdr {
+  PACK_STRUCT_FIELD(u16_t src);
+  PACK_STRUCT_FIELD(u16_t dest);  /* src/dest UDP ports */
+  PACK_STRUCT_FIELD(u16_t len);
+  PACK_STRUCT_FIELD(u16_t chksum);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+#define UDP_FLAGS_NOCHKSUM       0x01U
+#define UDP_FLAGS_UDPLITE        0x02U
+#define UDP_FLAGS_CONNECTED      0x04U
+#define UDP_FLAGS_MULTICAST_LOOP 0x08U
+
+struct udp_pcb;
+
+/** Function prototype for udp pcb receive callback functions
+ * addr and port are in same byte order as in the pcb
+ * The callback is responsible for freeing the pbuf
+ * if it's not used any more.
+ *
+ * ATTENTION: Be aware that 'addr' points into the pbuf 'p' so freeing this pbuf
+ *            makes 'addr' invalid, too.
+ *
+ * @param arg user supplied argument (udp_pcb.recv_arg)
+ * @param pcb the udp_pcb which received data
+ * @param p the packet buffer that was received
+ * @param addr the remote IP address from which the packet was received
+ * @param port the remote port from which the packet was received
+ */
+typedef void (*udp_recv_fn)(void *arg, struct udp_pcb *pcb, struct pbuf *p,
+    ip_addr_t *addr, u16_t port);
+
+
+struct udp_pcb {
+/* Common members of all PCB types */
+  IP_PCB;
+
+/* Protocol specific PCB members */
+
+  struct udp_pcb *next;
+
+  u8_t flags;
+  /** ports are in host byte order */
+  u16_t local_port, remote_port;
+
+#if LWIP_IGMP
+  /** outgoing network interface for multicast packets */
+  ip_addr_t multicast_ip;
+#endif /* LWIP_IGMP */
+
+#if LWIP_UDPLITE
+  /** used for UDP_LITE only */
+  u16_t chksum_len_rx, chksum_len_tx;
+#endif /* LWIP_UDPLITE */
+
+  /** receive callback function */
+  udp_recv_fn recv;
+  /** user-supplied argument for the recv callback */
+  void *recv_arg;  
+};
+/* udp_pcbs export for exernal reference (e.g. SNMP agent) */
+extern struct udp_pcb *udp_pcbs;
+
+/* The following functions is the application layer interface to the
+   UDP code. */
+struct udp_pcb * udp_new        (void);
+void             udp_remove     (struct udp_pcb *pcb);
+err_t            udp_bind       (struct udp_pcb *pcb, ip_addr_t *ipaddr,
+                                 u16_t port);
+err_t            udp_connect    (struct udp_pcb *pcb, ip_addr_t *ipaddr,
+                                 u16_t port);
+void             udp_disconnect (struct udp_pcb *pcb);
+void             udp_recv       (struct udp_pcb *pcb, udp_recv_fn recv,
+                                 void *recv_arg);
+err_t            udp_sendto_if  (struct udp_pcb *pcb, struct pbuf *p,
+                                 ip_addr_t *dst_ip, u16_t dst_port,
+                                 struct netif *netif);
+err_t            udp_sendto     (struct udp_pcb *pcb, struct pbuf *p,
+                                 ip_addr_t *dst_ip, u16_t dst_port);
+err_t            udp_send       (struct udp_pcb *pcb, struct pbuf *p);
+
+#if LWIP_CHECKSUM_ON_COPY
+err_t            udp_sendto_if_chksum(struct udp_pcb *pcb, struct pbuf *p,
+                                 ip_addr_t *dst_ip, u16_t dst_port,
+                                 struct netif *netif, u8_t have_chksum,
+                                 u16_t chksum);
+err_t            udp_sendto_chksum(struct udp_pcb *pcb, struct pbuf *p,
+                                 ip_addr_t *dst_ip, u16_t dst_port,
+                                 u8_t have_chksum, u16_t chksum);
+err_t            udp_send_chksum(struct udp_pcb *pcb, struct pbuf *p,
+                                 u8_t have_chksum, u16_t chksum);
+#endif /* LWIP_CHECKSUM_ON_COPY */
+
+#define          udp_flags(pcb) ((pcb)->flags)
+#define          udp_setflags(pcb, f)  ((pcb)->flags = (f))
+
+/* The following functions are the lower layer interface to UDP. */
+void             udp_input      (struct pbuf *p, struct netif *inp);
+
+#define udp_init() /* Compatibility define, not init needed. */
+
+#if UDP_DEBUG
+void udp_debug_print(struct udp_hdr *udphdr);
+#else
+#define udp_debug_print(udphdr)
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_UDP */
+
+#endif /* __LWIP_UDP_H__ */
diff --git a/core/lwip/src/include/lwipopts.h b/core/lwip/src/include/lwipopts.h
new file mode 100644
index 00000000..e0d39b89
--- /dev/null
+++ b/core/lwip/src/include/lwipopts.h
@@ -0,0 +1,73 @@
+#ifndef __LWIPOPTS_H__
+#define __LWIPOPTS_H__
+
+#include <byteswap.h>
+#include <netinet/in.h>
+
+#define SYS_LIGHTWEIGHT_PROT	1
+#define LWIP_NETIF_API		1
+#define LWIP_DNS		1
+#define LWIP_UDP		1
+#define LWIP_TCP		1
+#define LWIP_SO_RCVTIMEO	1
+#define LWIP_ICMP		1
+
+#define TCPIP_MBOX_SIZE         	512
+#define TCPIP_THREAD_PRIO		-10
+#define TCPIP_THREAD_STACKSIZE		32768
+
+#define DEFAULT_UDP_RECVMBOX_SIZE	16
+#define DEFAULT_TCP_RECVMBOX_SIZE	128
+#define DEFAULT_ACCEPTMBOX_SIZE		4
+
+#define LWIP_SOCKET			0
+
+#define MEM_LIBC_MALLOC			0
+#define MEMP_MEM_MALLOC			0
+
+#define MEMP_NUM_TCP_PCB		64
+#define MEMP_NUM_TCP_SEG		256
+#define MEMP_NUM_REASSDATA		32
+#define MEMP_NUM_SYS_TIMEOUT		8
+#define MEMP_NUM_NETCONN		64
+#define MEMP_NUM_TCPIP_MSG_API		64
+#define MEMP_NUM_TCPIP_MSG_INPKT	64
+#define MEMP_NUM_NETBUF			128
+#define PBUF_POOL_SIZE			256
+#define ARP_TABLE_SIZE			16
+#define IP_REASS_MAX_PBUFS		64
+#define IP_REASS_MAXAGE			10
+
+#define LWIP_NETIF_API		1
+
+#define LWIP_DNS		1
+#define DNS_TABLE_SIZE		16
+#define DNS_MAX_SERVERS		4
+#define TCP_MSS			1460
+#define TCP_WND			64000
+#define TCP_SND_BUF		(4*TCP_MSS)
+#define LWIP_TCP_TIMESTAMPS	1
+
+/*
+ * IANA says to use dynamic port numbers above 49152, but some
+ * very high numbers are known to be (ab)used, too.
+ */
+#define TCP_LOCAL_PORT_RANGE_START 49152
+#define TCP_LOCAL_PORT_RANGE_END   57343
+#define UDP_LOCAL_PORT_RANGE_START 49152
+#define UDP_LOCAL_PORT_RANGE_END   57343
+
+#define ETHARP_TRUST_IP_MAC	0
+ 
+#define LWIP_STATS		1
+#define LWIP_STATS_DISPLAY	1
+
+#define LWIP_PLATFORM_BYTESWAP	1
+#define LWIP_PLATFORM_HTONS(x)	bswap_16(x)
+#define LWIP_PLATFORM_HTONL(x)	bswap_32(x)
+
+#define LWIP_PREFIX_BYTEORDER_FUNCS	0
+#define LWIP_COMPAT_MUTEX	1
+
+void undiarp_tmr(void);
+#endif /* __LWIPOPTS_H__ */
diff --git a/core/lwip/src/include/netif/etharp.h b/core/lwip/src/include/netif/etharp.h
new file mode 100644
index 00000000..691575fa
--- /dev/null
+++ b/core/lwip/src/include/netif/etharp.h
@@ -0,0 +1,221 @@
+/*
+ * Copyright (c) 2001-2003 Swedish Institute of Computer Science.
+ * Copyright (c) 2003-2004 Leon Woestenberg <leon.woestenberg@axon.tv>
+ * Copyright (c) 2003-2004 Axon Digital Design B.V., The Netherlands.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#ifndef __NETIF_ETHARP_H__
+#define __NETIF_ETHARP_H__
+
+#include "lwip/opt.h"
+
+#if LWIP_ARP || LWIP_ETHERNET /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/pbuf.h"
+#include "lwip/ip_addr.h"
+#include "lwip/netif.h"
+#include "lwip/ip.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef ETHARP_HWADDR_LEN
+#define ETHARP_HWADDR_LEN     6
+#endif
+
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct eth_addr {
+  PACK_STRUCT_FIELD(u8_t addr[ETHARP_HWADDR_LEN]);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+/** Ethernet header */
+struct eth_hdr {
+#if ETH_PAD_SIZE
+  PACK_STRUCT_FIELD(u8_t padding[ETH_PAD_SIZE]);
+#endif
+  PACK_STRUCT_FIELD(struct eth_addr dest);
+  PACK_STRUCT_FIELD(struct eth_addr src);
+  PACK_STRUCT_FIELD(u16_t type);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+#define SIZEOF_ETH_HDR (14 + ETH_PAD_SIZE)
+
+#if ETHARP_SUPPORT_VLAN
+
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+/** VLAN header inserted between ethernet header and payload
+ * if 'type' in ethernet header is ETHTYPE_VLAN.
+ * See IEEE802.Q */
+struct eth_vlan_hdr {
+  PACK_STRUCT_FIELD(u16_t prio_vid);
+  PACK_STRUCT_FIELD(u16_t tpid);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+#define SIZEOF_VLAN_HDR 4
+#define VLAN_ID(vlan_hdr) (htons((vlan_hdr)->prio_vid) & 0xFFF)
+
+#endif /* ETHARP_SUPPORT_VLAN */
+
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+/** the ARP message, see RFC 826 ("Packet format") */
+struct etharp_hdr {
+  PACK_STRUCT_FIELD(u16_t hwtype);
+  PACK_STRUCT_FIELD(u16_t proto);
+  PACK_STRUCT_FIELD(u8_t  hwlen);
+  PACK_STRUCT_FIELD(u8_t  protolen);
+  PACK_STRUCT_FIELD(u16_t opcode);
+  PACK_STRUCT_FIELD(struct eth_addr shwaddr);
+  PACK_STRUCT_FIELD(struct ip_addr2 sipaddr);
+  PACK_STRUCT_FIELD(struct eth_addr dhwaddr);
+  PACK_STRUCT_FIELD(struct ip_addr2 dipaddr);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+#define SIZEOF_ETHARP_HDR 28
+#define SIZEOF_ETHARP_PACKET (SIZEOF_ETH_HDR + SIZEOF_ETHARP_HDR)
+
+/** 5 seconds period */
+#define ARP_TMR_INTERVAL 5000
+
+#define ETHTYPE_ARP       0x0806U
+#define ETHTYPE_IP        0x0800U
+#define ETHTYPE_VLAN      0x8100U
+#define ETHTYPE_PPPOEDISC 0x8863U  /* PPP Over Ethernet Discovery Stage */
+#define ETHTYPE_PPPOE     0x8864U  /* PPP Over Ethernet Session Stage */
+
+/** MEMCPY-like macro to copy to/from struct eth_addr's that are local variables
+ * or known to be 32-bit aligned within the protocol header. */
+#ifndef ETHADDR32_COPY
+#define ETHADDR32_COPY(src, dst)  SMEMCPY(src, dst, ETHARP_HWADDR_LEN)
+#endif
+
+/** MEMCPY-like macro to copy to/from struct eth_addr's that are no local
+ * variables and known to be 16-bit aligned within the protocol header. */
+#ifndef ETHADDR16_COPY
+#define ETHADDR16_COPY(src, dst)  SMEMCPY(src, dst, ETHARP_HWADDR_LEN)
+#endif
+
+#if LWIP_ARP /* don't build if not configured for use in lwipopts.h */
+
+/** ARP message types (opcodes) */
+#define ARP_REQUEST 1
+#define ARP_REPLY   2
+
+/** Define this to 1 and define LWIP_ARP_FILTER_NETIF_FN(pbuf, netif, type)
+ * to a filter function that returns the correct netif when using multiple
+ * netifs on one hardware interface where the netif's low-level receive
+ * routine cannot decide for the correct netif (e.g. when mapping multiple
+ * IP addresses to one hardware interface).
+ */
+#ifndef LWIP_ARP_FILTER_NETIF
+#define LWIP_ARP_FILTER_NETIF 0
+#endif
+
+#if ARP_QUEUEING
+/** struct for queueing outgoing packets for unknown address
+  * defined here to be accessed by memp.h
+  */
+struct etharp_q_entry {
+  struct etharp_q_entry *next;
+  struct pbuf *p;
+};
+#endif /* ARP_QUEUEING */
+
+#define etharp_init() /* Compatibility define, not init needed. */
+void etharp_tmr(void);
+s8_t etharp_find_addr(struct netif *netif, ip_addr_t *ipaddr,
+         struct eth_addr **eth_ret, ip_addr_t **ip_ret);
+err_t etharp_output(struct netif *netif, struct pbuf *q, ip_addr_t *ipaddr);
+err_t etharp_query(struct netif *netif, ip_addr_t *ipaddr, struct pbuf *q);
+err_t etharp_request(struct netif *netif, ip_addr_t *ipaddr);
+/** For Ethernet network interfaces, we might want to send "gratuitous ARP";
+ *  this is an ARP packet sent by a node in order to spontaneously cause other
+ *  nodes to update an entry in their ARP cache.
+ *  From RFC 3220 "IP Mobility Support for IPv4" section 4.6. */
+#define etharp_gratuitous(netif) etharp_request((netif), &(netif)->ip_addr)
+
+#if ETHARP_SUPPORT_STATIC_ENTRIES
+err_t etharp_add_static_entry(ip_addr_t *ipaddr, struct eth_addr *ethaddr);
+err_t etharp_remove_static_entry(ip_addr_t *ipaddr);
+#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
+
+#if LWIP_AUTOIP
+err_t etharp_raw(struct netif *netif, const struct eth_addr *ethsrc_addr,
+                 const struct eth_addr *ethdst_addr,
+                 const struct eth_addr *hwsrc_addr, const ip_addr_t *ipsrc_addr,
+                 const struct eth_addr *hwdst_addr, const ip_addr_t *ipdst_addr,
+                 const u16_t opcode);
+#endif /* LWIP_AUTOIP */
+
+#endif /* LWIP_ARP */
+
+err_t ethernet_input(struct pbuf *p, struct netif *netif);
+
+#define eth_addr_cmp(addr1, addr2) (memcmp((addr1)->addr, (addr2)->addr, ETHARP_HWADDR_LEN) == 0)
+
+extern const struct eth_addr ethbroadcast, ethzero;
+
+#endif /* LWIP_ARP || LWIP_ETHERNET */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __NETIF_ARP_H__ */
diff --git a/core/lwip/src/include/netif/ppp_oe.h b/core/lwip/src/include/netif/ppp_oe.h
new file mode 100644
index 00000000..e1cdfa51
--- /dev/null
+++ b/core/lwip/src/include/netif/ppp_oe.h
@@ -0,0 +1,190 @@
+/*****************************************************************************
+* ppp_oe.h - PPP Over Ethernet implementation for lwIP.
+*
+* Copyright (c) 2006 by Marc Boucher, Services Informatiques (MBSI) inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 06-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+*****************************************************************************/
+
+
+
+/* based on NetBSD: if_pppoe.c,v 1.64 2006/01/31 23:50:15 martin Exp */
+
+/*-
+ * Copyright (c) 2002 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Martin Husemann <martin@NetBSD.org>.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *        This product includes software developed by the NetBSD
+ *        Foundation, Inc. and its contributors.
+ * 4. Neither the name of The NetBSD Foundation nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+#ifndef PPP_OE_H
+#define PPP_OE_H
+
+#include "lwip/opt.h"
+
+#if PPPOE_SUPPORT > 0
+
+#include "netif/etharp.h"
+
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct pppoehdr {
+  PACK_STRUCT_FIELD(u8_t vertype);
+  PACK_STRUCT_FIELD(u8_t code);
+  PACK_STRUCT_FIELD(u16_t session);
+  PACK_STRUCT_FIELD(u16_t plen);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct pppoetag {
+  PACK_STRUCT_FIELD(u16_t tag);
+  PACK_STRUCT_FIELD(u16_t len);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+
+#define PPPOE_STATE_INITIAL   0
+#define PPPOE_STATE_PADI_SENT 1
+#define PPPOE_STATE_PADR_SENT 2
+#define PPPOE_STATE_SESSION   3
+#define PPPOE_STATE_CLOSING   4
+/* passive */
+#define PPPOE_STATE_PADO_SENT 1
+
+#define PPPOE_HEADERLEN       sizeof(struct pppoehdr)
+#define PPPOE_VERTYPE         0x11    /* VER=1, TYPE = 1 */
+
+#define PPPOE_TAG_EOL         0x0000  /* end of list */
+#define PPPOE_TAG_SNAME       0x0101  /* service name */
+#define PPPOE_TAG_ACNAME      0x0102  /* access concentrator name */
+#define PPPOE_TAG_HUNIQUE     0x0103  /* host unique */
+#define PPPOE_TAG_ACCOOKIE    0x0104  /* AC cookie */
+#define PPPOE_TAG_VENDOR      0x0105  /* vendor specific */
+#define PPPOE_TAG_RELAYSID    0x0110  /* relay session id */
+#define PPPOE_TAG_SNAME_ERR   0x0201  /* service name error */
+#define PPPOE_TAG_ACSYS_ERR   0x0202  /* AC system error */
+#define PPPOE_TAG_GENERIC_ERR 0x0203  /* gerneric error */
+
+#define PPPOE_CODE_PADI       0x09    /* Active Discovery Initiation */
+#define PPPOE_CODE_PADO       0x07    /* Active Discovery Offer */
+#define PPPOE_CODE_PADR       0x19    /* Active Discovery Request */
+#define PPPOE_CODE_PADS       0x65    /* Active Discovery Session confirmation */
+#define PPPOE_CODE_PADT       0xA7    /* Active Discovery Terminate */
+
+#ifndef ETHERMTU
+#define ETHERMTU 1500
+#endif
+
+/* two byte PPP protocol discriminator, then IP data */
+#define PPPOE_MAXMTU          (ETHERMTU-PPPOE_HEADERLEN-2)
+
+#ifndef PPPOE_MAX_AC_COOKIE_LEN
+#define PPPOE_MAX_AC_COOKIE_LEN   64
+#endif
+
+struct pppoe_softc {
+  struct pppoe_softc *next;
+  struct netif *sc_ethif;      /* ethernet interface we are using */
+  int sc_pd;                   /* ppp unit number */
+  void (*sc_linkStatusCB)(int pd, int up);
+
+  int sc_state;                /* discovery phase or session connected */
+  struct eth_addr sc_dest;     /* hardware address of concentrator */
+  u16_t sc_session;            /* PPPoE session id */
+
+#ifdef PPPOE_TODO
+  char *sc_service_name;       /* if != NULL: requested name of service */
+  char *sc_concentrator_name;  /* if != NULL: requested concentrator id */
+#endif /* PPPOE_TODO */
+  u8_t sc_ac_cookie[PPPOE_MAX_AC_COOKIE_LEN]; /* content of AC cookie we must echo back */
+  size_t sc_ac_cookie_len;     /* length of cookie data */
+#ifdef PPPOE_SERVER
+  u8_t *sc_hunique;            /* content of host unique we must echo back */
+  size_t sc_hunique_len;       /* length of host unique */
+#endif
+  int sc_padi_retried;         /* number of PADI retries already done */
+  int sc_padr_retried;         /* number of PADR retries already done */
+};
+
+
+#define pppoe_init() /* compatibility define, no initialization needed */
+
+err_t pppoe_create(struct netif *ethif, int pd, void (*linkStatusCB)(int pd, int up), struct pppoe_softc **scptr);
+err_t pppoe_destroy(struct netif *ifp);
+
+int pppoe_connect(struct pppoe_softc *sc);
+void pppoe_disconnect(struct pppoe_softc *sc);
+
+void pppoe_disc_input(struct netif *netif, struct pbuf *p);
+void pppoe_data_input(struct netif *netif, struct pbuf *p);
+
+err_t pppoe_xmit(struct pppoe_softc *sc, struct pbuf *pb);
+
+/** used in ppp.c */
+#define PPPOE_HDRLEN (sizeof(struct eth_hdr) + PPPOE_HEADERLEN)
+
+#endif /* PPPOE_SUPPORT */
+
+#endif /* PPP_OE_H */
diff --git a/core/lwip/src/include/netif/slipif.h b/core/lwip/src/include/netif/slipif.h
new file mode 100644
index 00000000..ccd03c8a
--- /dev/null
+++ b/core/lwip/src/include/netif/slipif.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2001, Swedish Institute of Computer Science.
+ * All rights reserved. 
+ *
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions 
+ * are met: 
+ * 1. Redistributions of source code must retain the above copyright 
+ *    notice, this list of conditions and the following disclaimer. 
+ * 2. Redistributions in binary form must reproduce the above copyright 
+ *    notice, this list of conditions and the following disclaimer in the 
+ *    documentation and/or other materials provided with the distribution. 
+ * 3. Neither the name of the Institute nor the names of its contributors 
+ *    may be used to endorse or promote products derived from this software 
+ *    without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
+ * SUCH DAMAGE. 
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+#ifndef __NETIF_SLIPIF_H__
+#define __NETIF_SLIPIF_H__
+
+#include "lwip/netif.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+err_t slipif_init(struct netif * netif);
+void slipif_poll(struct netif *netif);
+
+#ifdef __cplusplus
+}
+#endif
+ 
+#endif 
+
diff --git a/core/lwip/src/netif/FILES b/core/lwip/src/netif/FILES
new file mode 100644
index 00000000..099dbf3e
--- /dev/null
+++ b/core/lwip/src/netif/FILES
@@ -0,0 +1,29 @@
+This directory contains generic network interface device drivers that
+do not contain any hardware or architecture specific code. The files
+are:
+
+etharp.c
+          Implements the ARP (Address Resolution Protocol) over
+          Ethernet. The code in this file should be used together with
+          Ethernet device drivers. Note that this module has been
+          largely made Ethernet independent so you should be able to
+          adapt this for other link layers (such as Firewire).
+
+ethernetif.c
+          An example of how an Ethernet device driver could look. This
+          file can be used as a "skeleton" for developing new Ethernet
+          network device drivers. It uses the etharp.c ARP code.
+
+loopif.c
+          A "loopback" network interface driver. It requires configuration
+          through the define LWIP_LOOPIF_MULTITHREADING (see opt.h).
+
+slipif.c
+          A generic implementation of the SLIP (Serial Line IP)
+          protocol. It requires a sio (serial I/O) module to work.
+
+ppp/      Point-to-Point Protocol stack
+          The PPP stack has been ported from ucip (http://ucip.sourceforge.net).
+          It matches quite well to pppd 2.3.1 (http://ppp.samba.org), although
+          compared to that, it has some modifications for embedded systems and
+          the source code has been reordered a bit.
\ No newline at end of file
diff --git a/core/lwip/src/netif/etharp.c b/core/lwip/src/netif/etharp.c
new file mode 100644
index 00000000..b60dadd0
--- /dev/null
+++ b/core/lwip/src/netif/etharp.c
@@ -0,0 +1,1318 @@
+/**
+ * @file
+ * Address Resolution Protocol module for IP over Ethernet
+ *
+ * Functionally, ARP is divided into two parts. The first maps an IP address
+ * to a physical address when sending a packet, and the second part answers
+ * requests from other machines for our physical address.
+ *
+ * This implementation complies with RFC 826 (Ethernet ARP). It supports
+ * Gratuitious ARP from RFC3220 (IP Mobility Support for IPv4) section 4.6
+ * if an interface calls etharp_gratuitous(our_netif) upon address change.
+ */
+
+/*
+ * Copyright (c) 2001-2003 Swedish Institute of Computer Science.
+ * Copyright (c) 2003-2004 Leon Woestenberg <leon.woestenberg@axon.tv>
+ * Copyright (c) 2003-2004 Axon Digital Design B.V., The Netherlands.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ */
+ 
+#include "lwip/opt.h"
+
+#if LWIP_ARP || LWIP_ETHERNET
+
+#include "lwip/ip_addr.h"
+#include "lwip/def.h"
+#include "lwip/ip.h"
+#include "lwip/stats.h"
+#include "lwip/snmp.h"
+#include "lwip/dhcp.h"
+#include "lwip/autoip.h"
+#include "netif/etharp.h"
+
+#if PPPOE_SUPPORT
+#include "netif/ppp_oe.h"
+#endif /* PPPOE_SUPPORT */
+
+#include <string.h>
+
+const struct eth_addr ethbroadcast = {{0xff,0xff,0xff,0xff,0xff,0xff}};
+const struct eth_addr ethzero = {{0,0,0,0,0,0}};
+
+#if LWIP_ARP /* don't build if not configured for use in lwipopts.h */
+
+/** the time an ARP entry stays valid after its last update,
+ *  for ARP_TMR_INTERVAL = 5000, this is
+ *  (240 * 5) seconds = 20 minutes.
+ */
+#define ARP_MAXAGE 240
+/** the time an ARP entry stays pending after first request,
+ *  for ARP_TMR_INTERVAL = 5000, this is
+ *  (2 * 5) seconds = 10 seconds.
+ * 
+ *  @internal Keep this number at least 2, otherwise it might
+ *  run out instantly if the timeout occurs directly after a request.
+ */
+#define ARP_MAXPENDING 2
+
+#define HWTYPE_ETHERNET 1
+
+enum etharp_state {
+  ETHARP_STATE_EMPTY = 0,
+  ETHARP_STATE_PENDING,
+  ETHARP_STATE_STABLE
+};
+
+struct etharp_entry {
+#if ARP_QUEUEING
+  /** Pointer to queue of pending outgoing packets on this ARP entry. */
+  struct etharp_q_entry *q;
+#else /* ARP_QUEUEING */
+  /** Pointer to a single pending outgoing packet on this ARP entry. */
+  struct pbuf *q;
+#endif /* ARP_QUEUEING */
+  ip_addr_t ipaddr;
+  struct eth_addr ethaddr;
+#if LWIP_SNMP
+  struct netif *netif;
+#endif /* LWIP_SNMP */
+  u8_t state;
+  u8_t ctime;
+#if ETHARP_SUPPORT_STATIC_ENTRIES
+  u8_t static_entry;
+#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
+};
+
+static struct etharp_entry arp_table[ARP_TABLE_SIZE];
+
+#if !LWIP_NETIF_HWADDRHINT
+static u8_t etharp_cached_entry;
+#endif /* !LWIP_NETIF_HWADDRHINT */
+
+/** Try hard to create a new entry - we want the IP address to appear in
+    the cache (even if this means removing an active entry or so). */
+#define ETHARP_FLAG_TRY_HARD     1
+#define ETHARP_FLAG_FIND_ONLY    2
+#define ETHARP_FLAG_STATIC_ENTRY 4
+
+#if LWIP_NETIF_HWADDRHINT
+#define ETHARP_SET_HINT(netif, hint)  if (((netif) != NULL) && ((netif)->addr_hint != NULL))  \
+                                      *((netif)->addr_hint) = (hint);
+#else /* LWIP_NETIF_HWADDRHINT */
+#define ETHARP_SET_HINT(netif, hint)  (etharp_cached_entry = (hint))
+#endif /* LWIP_NETIF_HWADDRHINT */
+
+static err_t update_arp_entry(struct netif *netif, ip_addr_t *ipaddr, struct eth_addr *ethaddr, u8_t flags);
+
+
+/* Some checks, instead of etharp_init(): */
+#if (LWIP_ARP && (ARP_TABLE_SIZE > 0x7f))
+  #error "ARP_TABLE_SIZE must fit in an s8_t, you have to reduce it in your lwipopts.h"
+#endif
+
+
+#if ARP_QUEUEING
+/**
+ * Free a complete queue of etharp entries
+ *
+ * @param q a qeueue of etharp_q_entry's to free
+ */
+static void
+free_etharp_q(struct etharp_q_entry *q)
+{
+  struct etharp_q_entry *r;
+  LWIP_ASSERT("q != NULL", q != NULL);
+  LWIP_ASSERT("q->p != NULL", q->p != NULL);
+  while (q) {
+    r = q;
+    q = q->next;
+    LWIP_ASSERT("r->p != NULL", (r->p != NULL));
+    pbuf_free(r->p);
+    memp_free(MEMP_ARP_QUEUE, r);
+  }
+}
+#else /* ARP_QUEUEING */
+
+/** Compatibility define: free the queued pbuf */
+#define free_etharp_q(q) pbuf_free(q)
+
+#endif /* ARP_QUEUEING */
+
+/** Clean up ARP table entries */
+static void
+free_entry(int i)
+{
+  /* remove from SNMP ARP index tree */
+  snmp_delete_arpidx_tree(arp_table[i].netif, &arp_table[i].ipaddr);
+  /* and empty packet queue */
+  if (arp_table[i].q != NULL) {
+    /* remove all queued packets */
+    LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer: freeing entry %"U16_F", packet queue %p.\n", (u16_t)i, (void *)(arp_table[i].q)));
+    free_etharp_q(arp_table[i].q);
+    arp_table[i].q = NULL;
+  }
+  /* recycle entry for re-use */      
+  arp_table[i].state = ETHARP_STATE_EMPTY;
+#if ETHARP_SUPPORT_STATIC_ENTRIES
+  arp_table[i].static_entry = 0;
+#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
+#ifdef LWIP_DEBUG
+  /* for debugging, clean out the complete entry */
+  arp_table[i].ctime = 0;
+#if LWIP_SNMP
+  arp_table[i].netif = NULL;
+#endif /* LWIP_SNMP */
+  ip_addr_set_zero(&arp_table[i].ipaddr);
+  arp_table[i].ethaddr = ethzero;
+#endif /* LWIP_DEBUG */
+}
+
+/**
+ * Clears expired entries in the ARP table.
+ *
+ * This function should be called every ETHARP_TMR_INTERVAL milliseconds (5 seconds),
+ * in order to expire entries in the ARP table.
+ */
+void
+etharp_tmr(void)
+{
+  u8_t i;
+
+  LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer\n"));
+  /* remove expired entries from the ARP table */
+  for (i = 0; i < ARP_TABLE_SIZE; ++i) {
+    u8_t state = arp_table[i].state;
+    if (state != ETHARP_STATE_EMPTY
+#if ETHARP_SUPPORT_STATIC_ENTRIES
+      && (arp_table[i].static_entry == 0)
+#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
+      ) {
+      arp_table[i].ctime++;
+      if ((arp_table[i].ctime >= ARP_MAXAGE) ||
+          ((arp_table[i].state == ETHARP_STATE_PENDING)  &&
+           (arp_table[i].ctime >= ARP_MAXPENDING))) {
+        /* pending or stable entry has become old! */
+        LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer: expired %s entry %"U16_F".\n",
+             arp_table[i].state == ETHARP_STATE_STABLE ? "stable" : "pending", (u16_t)i));
+        /* clean up entries that have just been expired */
+        free_entry(i);
+      }
+#if ARP_QUEUEING
+      /* still pending entry? (not expired) */
+      if (arp_table[i].state == ETHARP_STATE_PENDING) {
+        /* resend an ARP query here? */
+      }
+#endif /* ARP_QUEUEING */
+    }
+  }
+}
+
+/**
+ * Search the ARP table for a matching or new entry.
+ * 
+ * If an IP address is given, return a pending or stable ARP entry that matches
+ * the address. If no match is found, create a new entry with this address set,
+ * but in state ETHARP_EMPTY. The caller must check and possibly change the
+ * state of the returned entry.
+ * 
+ * If ipaddr is NULL, return a initialized new entry in state ETHARP_EMPTY.
+ * 
+ * In all cases, attempt to create new entries from an empty entry. If no
+ * empty entries are available and ETHARP_FLAG_TRY_HARD flag is set, recycle
+ * old entries. Heuristic choose the least important entry for recycling.
+ *
+ * @param ipaddr IP address to find in ARP cache, or to add if not found.
+ * @param flags @see definition of ETHARP_FLAG_*
+ * @param netif netif related to this address (used for NETIF_HWADDRHINT)
+ *  
+ * @return The ARP entry index that matched or is created, ERR_MEM if no
+ * entry is found or could be recycled.
+ */
+static s8_t
+find_entry(ip_addr_t *ipaddr, u8_t flags)
+{
+  s8_t old_pending = ARP_TABLE_SIZE, old_stable = ARP_TABLE_SIZE;
+  s8_t empty = ARP_TABLE_SIZE;
+  u8_t i = 0, age_pending = 0, age_stable = 0;
+  /* oldest entry with packets on queue */
+  s8_t old_queue = ARP_TABLE_SIZE;
+  /* its age */
+  u8_t age_queue = 0;
+
+  /**
+   * a) do a search through the cache, remember candidates
+   * b) select candidate entry
+   * c) create new entry
+   */
+
+  /* a) in a single search sweep, do all of this
+   * 1) remember the first empty entry (if any)
+   * 2) remember the oldest stable entry (if any)
+   * 3) remember the oldest pending entry without queued packets (if any)
+   * 4) remember the oldest pending entry with queued packets (if any)
+   * 5) search for a matching IP entry, either pending or stable
+   *    until 5 matches, or all entries are searched for.
+   */
+
+  for (i = 0; i < ARP_TABLE_SIZE; ++i) {
+    u8_t state = arp_table[i].state;
+    /* no empty entry found yet and now we do find one? */
+    if ((empty == ARP_TABLE_SIZE) && (state == ETHARP_STATE_EMPTY)) {
+      LWIP_DEBUGF(ETHARP_DEBUG, ("find_entry: found empty entry %"U16_F"\n", (u16_t)i));
+      /* remember first empty entry */
+      empty = i;
+    } else if (state != ETHARP_STATE_EMPTY) {
+      LWIP_ASSERT("state == ETHARP_STATE_PENDING || state == ETHARP_STATE_STABLE",
+        state == ETHARP_STATE_PENDING || state == ETHARP_STATE_STABLE);
+      /* if given, does IP address match IP address in ARP entry? */
+      if (ipaddr && ip_addr_cmp(ipaddr, &arp_table[i].ipaddr)) {
+        LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: found matching entry %"U16_F"\n", (u16_t)i));
+        /* found exact IP address match, simply bail out */
+        return i;
+      }
+      /* pending entry? */
+      if (state == ETHARP_STATE_PENDING) {
+        /* pending with queued packets? */
+        if (arp_table[i].q != NULL) {
+          if (arp_table[i].ctime >= age_queue) {
+            old_queue = i;
+            age_queue = arp_table[i].ctime;
+          }
+        } else
+        /* pending without queued packets? */
+        {
+          if (arp_table[i].ctime >= age_pending) {
+            old_pending = i;
+            age_pending = arp_table[i].ctime;
+          }
+        }
+      /* stable entry? */
+      } else if (state == ETHARP_STATE_STABLE) {
+#if ETHARP_SUPPORT_STATIC_ENTRIES
+        /* don't record old_stable for static entries since they never expire */
+        if (arp_table[i].static_entry == 0)
+#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
+        {
+          /* remember entry with oldest stable entry in oldest, its age in maxtime */
+          if (arp_table[i].ctime >= age_stable) {
+            old_stable = i;
+            age_stable = arp_table[i].ctime;
+          }
+        }
+      }
+    }
+  }
+  /* { we have no match } => try to create a new entry */
+   
+  /* don't create new entry, only search? */
+  if (((flags & ETHARP_FLAG_FIND_ONLY) != 0) ||
+      /* or no empty entry found and not allowed to recycle? */
+      ((empty == ARP_TABLE_SIZE) && ((flags & ETHARP_FLAG_TRY_HARD) == 0))) {
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: no empty entry found and not allowed to recycle\n"));
+    return (s8_t)ERR_MEM;
+  }
+  
+  /* b) choose the least destructive entry to recycle:
+   * 1) empty entry
+   * 2) oldest stable entry
+   * 3) oldest pending entry without queued packets
+   * 4) oldest pending entry with queued packets
+   * 
+   * { ETHARP_FLAG_TRY_HARD is set at this point }
+   */ 
+
+  /* 1) empty entry available? */
+  if (empty < ARP_TABLE_SIZE) {
+    i = empty;
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting empty entry %"U16_F"\n", (u16_t)i));
+  } else {
+    /* 2) found recyclable stable entry? */
+    if (old_stable < ARP_TABLE_SIZE) {
+      /* recycle oldest stable*/
+      i = old_stable;
+      LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting oldest stable entry %"U16_F"\n", (u16_t)i));
+      /* no queued packets should exist on stable entries */
+      LWIP_ASSERT("arp_table[i].q == NULL", arp_table[i].q == NULL);
+    /* 3) found recyclable pending entry without queued packets? */
+    } else if (old_pending < ARP_TABLE_SIZE) {
+      /* recycle oldest pending */
+      i = old_pending;
+      LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting oldest pending entry %"U16_F" (without queue)\n", (u16_t)i));
+    /* 4) found recyclable pending entry with queued packets? */
+    } else if (old_queue < ARP_TABLE_SIZE) {
+      /* recycle oldest pending (queued packets are free in free_entry) */
+      i = old_queue;
+      LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting oldest pending entry %"U16_F", freeing packet queue %p\n", (u16_t)i, (void *)(arp_table[i].q)));
+      /* no empty or recyclable entries found */
+    } else {
+      LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: no empty or recyclable entries found\n"));
+      return (s8_t)ERR_MEM;
+    }
+
+    /* { empty or recyclable entry found } */
+    LWIP_ASSERT("i < ARP_TABLE_SIZE", i < ARP_TABLE_SIZE);
+    free_entry(i);
+  }
+
+  LWIP_ASSERT("i < ARP_TABLE_SIZE", i < ARP_TABLE_SIZE);
+  LWIP_ASSERT("arp_table[i].state == ETHARP_STATE_EMPTY",
+    arp_table[i].state == ETHARP_STATE_EMPTY);
+
+  /* IP address given? */
+  if (ipaddr != NULL) {
+    /* set IP address */
+    ip_addr_copy(arp_table[i].ipaddr, *ipaddr);
+  }
+  arp_table[i].ctime = 0;
+#if ETHARP_SUPPORT_STATIC_ENTRIES
+  arp_table[i].static_entry = 0;
+#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
+  return (err_t)i;
+}
+
+/**
+ * Send an IP packet on the network using netif->linkoutput
+ * The ethernet header is filled in before sending.
+ *
+ * @params netif the lwIP network interface on which to send the packet
+ * @params p the packet to send, p->payload pointing to the (uninitialized) ethernet header
+ * @params src the source MAC address to be copied into the ethernet header
+ * @params dst the destination MAC address to be copied into the ethernet header
+ * @return ERR_OK if the packet was sent, any other err_t on failure
+ */
+static err_t
+etharp_send_ip(struct netif *netif, struct pbuf *p, struct eth_addr *src, struct eth_addr *dst)
+{
+  struct eth_hdr *ethhdr = (struct eth_hdr *)p->payload;
+
+  LWIP_ASSERT("netif->hwaddr_len must be the same as ETHARP_HWADDR_LEN for etharp!",
+              (netif->hwaddr_len == ETHARP_HWADDR_LEN));
+  ETHADDR32_COPY(&ethhdr->dest, dst);
+  ETHADDR16_COPY(&ethhdr->src, src);
+  ethhdr->type = PP_HTONS(ETHTYPE_IP);
+  LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_send_ip: sending packet %p\n", (void *)p));
+  /* send the packet */
+  return netif->linkoutput(netif, p);
+}
+
+/**
+ * Update (or insert) a IP/MAC address pair in the ARP cache.
+ *
+ * If a pending entry is resolved, any queued packets will be sent
+ * at this point.
+ * 
+ * @param netif netif related to this entry (used for NETIF_ADDRHINT)
+ * @param ipaddr IP address of the inserted ARP entry.
+ * @param ethaddr Ethernet address of the inserted ARP entry.
+ * @param flags @see definition of ETHARP_FLAG_*
+ *
+ * @return
+ * - ERR_OK Succesfully updated ARP cache.
+ * - ERR_MEM If we could not add a new ARP entry when ETHARP_FLAG_TRY_HARD was set.
+ * - ERR_ARG Non-unicast address given, those will not appear in ARP cache.
+ *
+ * @see pbuf_free()
+ */
+static err_t
+update_arp_entry(struct netif *netif, ip_addr_t *ipaddr, struct eth_addr *ethaddr, u8_t flags)
+{
+  s8_t i;
+  LWIP_ASSERT("netif->hwaddr_len == ETHARP_HWADDR_LEN", netif->hwaddr_len == ETHARP_HWADDR_LEN);
+  LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("update_arp_entry: %"U16_F".%"U16_F".%"U16_F".%"U16_F" - %02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F"\n",
+    ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr),
+    ethaddr->addr[0], ethaddr->addr[1], ethaddr->addr[2],
+    ethaddr->addr[3], ethaddr->addr[4], ethaddr->addr[5]));
+  /* non-unicast address? */
+  if (ip_addr_isany(ipaddr) ||
+      ip_addr_isbroadcast(ipaddr, netif) ||
+      ip_addr_ismulticast(ipaddr)) {
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("update_arp_entry: will not add non-unicast IP address to ARP cache\n"));
+    return ERR_ARG;
+  }
+  /* find or create ARP entry */
+  i = find_entry(ipaddr, flags);
+  /* bail out if no entry could be found */
+  if (i < 0) {
+    return (err_t)i;
+  }
+
+#if ETHARP_SUPPORT_STATIC_ENTRIES
+  if (flags & ETHARP_FLAG_STATIC_ENTRY) {
+    /* record static type */
+    arp_table[i].static_entry = 1;
+  }
+#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
+
+  /* mark it stable */
+  arp_table[i].state = ETHARP_STATE_STABLE;
+
+#if LWIP_SNMP
+  /* record network interface */
+  arp_table[i].netif = netif;
+#endif /* LWIP_SNMP */
+  /* insert in SNMP ARP index tree */
+  snmp_insert_arpidx_tree(netif, &arp_table[i].ipaddr);
+
+  LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("update_arp_entry: updating stable entry %"S16_F"\n", (s16_t)i));
+  /* update address */
+  ETHADDR32_COPY(&arp_table[i].ethaddr, ethaddr);
+  /* reset time stamp */
+  arp_table[i].ctime = 0;
+  /* this is where we will send out queued packets! */
+#if ARP_QUEUEING
+  while (arp_table[i].q != NULL) {
+    struct pbuf *p;
+    /* remember remainder of queue */
+    struct etharp_q_entry *q = arp_table[i].q;
+    /* pop first item off the queue */
+    arp_table[i].q = q->next;
+    /* get the packet pointer */
+    p = q->p;
+    /* now queue entry can be freed */
+    memp_free(MEMP_ARP_QUEUE, q);
+#else /* ARP_QUEUEING */
+  if (arp_table[i].q != NULL) {
+    struct pbuf *p = arp_table[i].q;
+    arp_table[i].q = NULL;
+#endif /* ARP_QUEUEING */
+    /* send the queued IP packet */
+    etharp_send_ip(netif, p, (struct eth_addr*)(netif->hwaddr), ethaddr);
+    /* free the queued IP packet */
+    pbuf_free(p);
+  }
+  return ERR_OK;
+}
+
+#if ETHARP_SUPPORT_STATIC_ENTRIES
+/** Add a new static entry to the ARP table. If an entry exists for the
+ * specified IP address, this entry is overwritten.
+ * If packets are queued for the specified IP address, they are sent out.
+ *
+ * @param ipaddr IP address for the new static entry
+ * @param ethaddr ethernet address for the new static entry
+ * @return @see return values of etharp_add_static_entry
+ */
+err_t
+etharp_add_static_entry(ip_addr_t *ipaddr, struct eth_addr *ethaddr)
+{
+  struct netif *netif;
+  LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_add_static_entry: %"U16_F".%"U16_F".%"U16_F".%"U16_F" - %02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F"\n",
+    ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr),
+    ethaddr->addr[0], ethaddr->addr[1], ethaddr->addr[2],
+    ethaddr->addr[3], ethaddr->addr[4], ethaddr->addr[5]));
+
+  netif = ip_route(ipaddr);
+  if (netif == NULL) {
+    return ERR_RTE;
+  }
+
+  return update_arp_entry(netif, ipaddr, ethaddr, ETHARP_FLAG_TRY_HARD | ETHARP_FLAG_STATIC_ENTRY);
+}
+
+/** Remove a static entry from the ARP table previously added with a call to
+ * etharp_add_static_entry.
+ *
+ * @param ipaddr IP address of the static entry to remove
+ * @return ERR_OK: entry removed
+ *         ERR_MEM: entry wasn't found
+ *         ERR_ARG: entry wasn't a static entry but a dynamic one
+ */
+err_t
+etharp_remove_static_entry(ip_addr_t *ipaddr)
+{
+  s8_t i;
+  LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_remove_static_entry: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+    ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
+
+  /* find or create ARP entry */
+  i = find_entry(ipaddr, ETHARP_FLAG_FIND_ONLY);
+  /* bail out if no entry could be found */
+  if (i < 0) {
+    return (err_t)i;
+  }
+
+  if ((arp_table[i].state != ETHARP_STATE_STABLE) ||
+    (arp_table[i].static_entry == 0)) {
+    /* entry wasn't a static entry, cannot remove it */
+    return ERR_ARG;
+  }
+  /* entry found, free it */
+  free_entry(i);
+  return ERR_OK;
+}
+#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
+
+/**
+ * Finds (stable) ethernet/IP address pair from ARP table
+ * using interface and IP address index.
+ * @note the addresses in the ARP table are in network order!
+ *
+ * @param netif points to interface index
+ * @param ipaddr points to the (network order) IP address index
+ * @param eth_ret points to return pointer
+ * @param ip_ret points to return pointer
+ * @return table index if found, -1 otherwise
+ */
+s8_t
+etharp_find_addr(struct netif *netif, ip_addr_t *ipaddr,
+         struct eth_addr **eth_ret, ip_addr_t **ip_ret)
+{
+  s8_t i;
+
+  LWIP_ASSERT("eth_ret != NULL && ip_ret != NULL",
+    eth_ret != NULL && ip_ret != NULL);
+
+  LWIP_UNUSED_ARG(netif);
+
+  i = find_entry(ipaddr, ETHARP_FLAG_FIND_ONLY);
+  if((i >= 0) && arp_table[i].state == ETHARP_STATE_STABLE) {
+      *eth_ret = &arp_table[i].ethaddr;
+      *ip_ret = &arp_table[i].ipaddr;
+      return i;
+  }
+  return -1;
+}
+
+#if ETHARP_TRUST_IP_MAC
+/**
+ * Updates the ARP table using the given IP packet.
+ *
+ * Uses the incoming IP packet's source address to update the
+ * ARP cache for the local network. The function does not alter
+ * or free the packet. This function must be called before the
+ * packet p is passed to the IP layer.
+ *
+ * @param netif The lwIP network interface on which the IP packet pbuf arrived.
+ * @param p The IP packet that arrived on netif.
+ *
+ * @return NULL
+ *
+ * @see pbuf_free()
+ */
+static void
+etharp_ip_input(struct netif *netif, struct pbuf *p)
+{
+  struct eth_hdr *ethhdr;
+  struct ip_hdr *iphdr;
+  ip_addr_t iphdr_src;
+  LWIP_ERROR("netif != NULL", (netif != NULL), return;);
+
+  /* Only insert an entry if the source IP address of the
+     incoming IP packet comes from a host on the local network. */
+  ethhdr = (struct eth_hdr *)p->payload;
+  iphdr = (struct ip_hdr *)((u8_t*)ethhdr + SIZEOF_ETH_HDR);
+#if ETHARP_SUPPORT_VLAN
+  if (ethhdr->type == PP_HTONS(ETHTYPE_VLAN)) {
+    iphdr = (struct ip_hdr *)((u8_t*)ethhdr + SIZEOF_ETH_HDR + SIZEOF_VLAN_HDR);
+  }
+#endif /* ETHARP_SUPPORT_VLAN */
+
+  ip_addr_copy(iphdr_src, iphdr->src);
+
+  /* source is not on the local network? */
+  if (!ip_addr_netcmp(&iphdr_src, &(netif->ip_addr), &(netif->netmask))) {
+    /* do nothing */
+    return;
+  }
+
+  LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_ip_input: updating ETHARP table.\n"));
+  /* update the source IP address in the cache, if present */
+  /* @todo We could use ETHARP_FLAG_TRY_HARD if we think we are going to talk
+   * back soon (for example, if the destination IP address is ours. */
+  update_arp_entry(netif, &iphdr_src, &(ethhdr->src), ETHARP_FLAG_FIND_ONLY);
+}
+#endif /* ETHARP_TRUST_IP_MAC */
+
+/**
+ * Responds to ARP requests to us. Upon ARP replies to us, add entry to cache  
+ * send out queued IP packets. Updates cache with snooped address pairs.
+ *
+ * Should be called for incoming ARP packets. The pbuf in the argument
+ * is freed by this function.
+ *
+ * @param netif The lwIP network interface on which the ARP packet pbuf arrived.
+ * @param ethaddr Ethernet address of netif.
+ * @param p The ARP packet that arrived on netif. Is freed by this function.
+ *
+ * @return NULL
+ *
+ * @see pbuf_free()
+ */
+static void
+etharp_arp_input(struct netif *netif, struct eth_addr *ethaddr, struct pbuf *p)
+{
+  struct etharp_hdr *hdr;
+  struct eth_hdr *ethhdr;
+  /* these are aligned properly, whereas the ARP header fields might not be */
+  ip_addr_t sipaddr, dipaddr;
+  u8_t for_us;
+#if LWIP_AUTOIP
+  const u8_t * ethdst_hwaddr;
+#endif /* LWIP_AUTOIP */
+
+  LWIP_ERROR("netif != NULL", (netif != NULL), return;);
+
+  /* drop short ARP packets: we have to check for p->len instead of p->tot_len here
+     since a struct etharp_hdr is pointed to p->payload, so it musn't be chained! */
+  if (p->len < SIZEOF_ETHARP_PACKET) {
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING,
+      ("etharp_arp_input: packet dropped, too short (%"S16_F"/%"S16_F")\n", p->tot_len,
+      (s16_t)SIZEOF_ETHARP_PACKET));
+    ETHARP_STATS_INC(etharp.lenerr);
+    ETHARP_STATS_INC(etharp.drop);
+    pbuf_free(p);
+    return;
+  }
+
+  ethhdr = (struct eth_hdr *)p->payload;
+  hdr = (struct etharp_hdr *)((u8_t*)ethhdr + SIZEOF_ETH_HDR);
+#if ETHARP_SUPPORT_VLAN
+  if (ethhdr->type == PP_HTONS(ETHTYPE_VLAN)) {
+    hdr = (struct etharp_hdr *)(((u8_t*)ethhdr) + SIZEOF_ETH_HDR + SIZEOF_VLAN_HDR);
+  }
+#endif /* ETHARP_SUPPORT_VLAN */
+
+  /* RFC 826 "Packet Reception": */
+  if ((hdr->hwtype != PP_HTONS(HWTYPE_ETHERNET)) ||
+      (hdr->hwlen != ETHARP_HWADDR_LEN) ||
+      (hdr->protolen != sizeof(ip_addr_t)) ||
+      (hdr->proto != PP_HTONS(ETHTYPE_IP)))  {
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING,
+      ("etharp_arp_input: packet dropped, wrong hw type, hwlen, proto, protolen or ethernet type (%"U16_F"/%"U16_F"/%"U16_F"/%"U16_F")\n",
+      hdr->hwtype, hdr->hwlen, hdr->proto, hdr->protolen));
+    ETHARP_STATS_INC(etharp.proterr);
+    ETHARP_STATS_INC(etharp.drop);
+    pbuf_free(p);
+    return;
+  }
+  ETHARP_STATS_INC(etharp.recv);
+
+#if LWIP_AUTOIP
+  /* We have to check if a host already has configured our random
+   * created link local address and continously check if there is
+   * a host with this IP-address so we can detect collisions */
+  autoip_arp_reply(netif, hdr);
+#endif /* LWIP_AUTOIP */
+
+  /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without
+   * structure packing (not using structure copy which breaks strict-aliasing rules). */
+  IPADDR2_COPY(&sipaddr, &hdr->sipaddr);
+  IPADDR2_COPY(&dipaddr, &hdr->dipaddr);
+
+  /* this interface is not configured? */
+  if (ip_addr_isany(&netif->ip_addr)) {
+    for_us = 0;
+  } else {
+    /* ARP packet directed to us? */
+    for_us = (u8_t)ip_addr_cmp(&dipaddr, &(netif->ip_addr));
+  }
+
+  /* ARP message directed to us?
+      -> add IP address in ARP cache; assume requester wants to talk to us,
+         can result in directly sending the queued packets for this host.
+     ARP message not directed to us?
+      ->  update the source IP address in the cache, if present */
+  update_arp_entry(netif, &sipaddr, &(hdr->shwaddr),
+                   for_us ? ETHARP_FLAG_TRY_HARD : ETHARP_FLAG_FIND_ONLY);
+
+  /* now act on the message itself */
+  switch (hdr->opcode) {
+  /* ARP request? */
+  case PP_HTONS(ARP_REQUEST):
+    /* ARP request. If it asked for our address, we send out a
+     * reply. In any case, we time-stamp any existing ARP entry,
+     * and possiby send out an IP packet that was queued on it. */
+
+    LWIP_DEBUGF (ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: incoming ARP request\n"));
+    /* ARP request for our address? */
+    if (for_us) {
+
+      LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: replying to ARP request for our IP address\n"));
+      /* Re-use pbuf to send ARP reply.
+         Since we are re-using an existing pbuf, we can't call etharp_raw since
+         that would allocate a new pbuf. */
+      hdr->opcode = htons(ARP_REPLY);
+
+      IPADDR2_COPY(&hdr->dipaddr, &hdr->sipaddr);
+      IPADDR2_COPY(&hdr->sipaddr, &netif->ip_addr);
+
+      LWIP_ASSERT("netif->hwaddr_len must be the same as ETHARP_HWADDR_LEN for etharp!",
+                  (netif->hwaddr_len == ETHARP_HWADDR_LEN));
+#if LWIP_AUTOIP
+      /* If we are using Link-Local, all ARP packets that contain a Link-Local
+       * 'sender IP address' MUST be sent using link-layer broadcast instead of
+       * link-layer unicast. (See RFC3927 Section 2.5, last paragraph) */
+      ethdst_hwaddr = ip_addr_islinklocal(&netif->ip_addr) ? (u8_t*)(ethbroadcast.addr) : hdr->shwaddr.addr;
+#endif /* LWIP_AUTOIP */
+
+      ETHADDR16_COPY(&hdr->dhwaddr, &hdr->shwaddr);
+#if LWIP_AUTOIP
+      ETHADDR16_COPY(&ethhdr->dest, ethdst_hwaddr);
+#else  /* LWIP_AUTOIP */
+      ETHADDR16_COPY(&ethhdr->dest, &hdr->shwaddr);
+#endif /* LWIP_AUTOIP */
+      ETHADDR16_COPY(&hdr->shwaddr, ethaddr);
+      ETHADDR16_COPY(&ethhdr->src, ethaddr);
+
+      /* hwtype, hwaddr_len, proto, protolen and the type in the ethernet header
+         are already correct, we tested that before */
+
+      /* return ARP reply */
+      netif->linkoutput(netif, p);
+    /* we are not configured? */
+    } else if (ip_addr_isany(&netif->ip_addr)) {
+      /* { for_us == 0 and netif->ip_addr.addr == 0 } */
+      LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: we are unconfigured, ARP request ignored.\n"));
+    /* request was not directed to us */
+    } else {
+      /* { for_us == 0 and netif->ip_addr.addr != 0 } */
+      LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: ARP request was not for us.\n"));
+    }
+    break;
+  case PP_HTONS(ARP_REPLY):
+    /* ARP reply. We already updated the ARP cache earlier. */
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: incoming ARP reply\n"));
+#if (LWIP_DHCP && DHCP_DOES_ARP_CHECK)
+    /* DHCP wants to know about ARP replies from any host with an
+     * IP address also offered to us by the DHCP server. We do not
+     * want to take a duplicate IP address on a single network.
+     * @todo How should we handle redundant (fail-over) interfaces? */
+    dhcp_arp_reply(netif, &sipaddr);
+#endif /* (LWIP_DHCP && DHCP_DOES_ARP_CHECK) */
+    break;
+  default:
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: ARP unknown opcode type %"S16_F"\n", htons(hdr->opcode)));
+    ETHARP_STATS_INC(etharp.err);
+    break;
+  }
+  /* free ARP packet */
+  pbuf_free(p);
+}
+
+/**
+ * Resolve and fill-in Ethernet address header for outgoing IP packet.
+ *
+ * For IP multicast and broadcast, corresponding Ethernet addresses
+ * are selected and the packet is transmitted on the link.
+ *
+ * For unicast addresses, the packet is submitted to etharp_query(). In
+ * case the IP address is outside the local network, the IP address of
+ * the gateway is used.
+ *
+ * @param netif The lwIP network interface which the IP packet will be sent on.
+ * @param q The pbuf(s) containing the IP packet to be sent.
+ * @param ipaddr The IP address of the packet destination.
+ *
+ * @return
+ * - ERR_RTE No route to destination (no gateway to external networks),
+ * or the return type of either etharp_query() or etharp_send_ip().
+ */
+err_t
+etharp_output(struct netif *netif, struct pbuf *q, ip_addr_t *ipaddr)
+{
+  struct eth_addr *dest, mcastaddr;
+
+  /* make room for Ethernet header - should not fail */
+  if (pbuf_header(q, sizeof(struct eth_hdr)) != 0) {
+    /* bail out */
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
+      ("etharp_output: could not allocate room for header.\n"));
+    LINK_STATS_INC(link.lenerr);
+    return ERR_BUF;
+  }
+
+  /* assume unresolved Ethernet address */
+  dest = NULL;
+  /* Determine on destination hardware address. Broadcasts and multicasts
+   * are special, other IP addresses are looked up in the ARP table. */
+
+  /* broadcast destination IP address? */
+  if (ip_addr_isbroadcast(ipaddr, netif)) {
+    /* broadcast on Ethernet also */
+    dest = (struct eth_addr *)&ethbroadcast;
+  /* multicast destination IP address? */
+  } else if (ip_addr_ismulticast(ipaddr)) {
+    /* Hash IP multicast address to MAC address.*/
+    mcastaddr.addr[0] = 0x01;
+    mcastaddr.addr[1] = 0x00;
+    mcastaddr.addr[2] = 0x5e;
+    mcastaddr.addr[3] = ip4_addr2(ipaddr) & 0x7f;
+    mcastaddr.addr[4] = ip4_addr3(ipaddr);
+    mcastaddr.addr[5] = ip4_addr4(ipaddr);
+    /* destination Ethernet address is multicast */
+    dest = &mcastaddr;
+  /* unicast destination IP address? */
+  } else {
+    /* outside local network? */
+    if (!ip_addr_netcmp(ipaddr, &(netif->ip_addr), &(netif->netmask)) &&
+        !ip_addr_islinklocal(ipaddr)) {
+#if LWIP_AUTOIP
+      struct ip_hdr *iphdr = (struct ip_hdr*)((u8_t*)q->payload +
+        sizeof(struct eth_hdr));
+      /* According to RFC 3297, chapter 2.6.2 (Forwarding Rules), a packet with
+         a link-local source address must always be "directly to its destination
+         on the same physical link. The host MUST NOT send the packet to any
+         router for forwarding". */
+      if (!ip_addr_islinklocal(&iphdr->src))
+#endif /* LWIP_AUTOIP */
+      {
+        /* interface has default gateway? */
+        if (!ip_addr_isany(&netif->gw)) {
+          /* send to hardware address of default gateway IP address */
+          ipaddr = &(netif->gw);
+        /* no default gateway available */
+        } else {
+          /* no route to destination error (default gateway missing) */
+          return ERR_RTE;
+        }
+      }
+    }
+#if LWIP_NETIF_HWADDRHINT
+    if (netif->addr_hint != NULL) {
+      /* per-pcb cached entry was given */
+      u8_t etharp_cached_entry = *(netif->addr_hint);
+      if (etharp_cached_entry < ARP_TABLE_SIZE) {
+#endif /* LWIP_NETIF_HWADDRHINT */
+        if ((arp_table[etharp_cached_entry].state == ETHARP_STATE_STABLE) &&
+            (ip_addr_cmp(ipaddr, &arp_table[etharp_cached_entry].ipaddr))) {
+          /* the per-pcb-cached entry is stable and the right one! */
+          ETHARP_STATS_INC(etharp.cachehit);
+          return etharp_send_ip(netif, q, (struct eth_addr*)(netif->hwaddr),
+            &arp_table[etharp_cached_entry].ethaddr);
+        }
+#if LWIP_NETIF_HWADDRHINT
+      }
+    }
+#endif /* LWIP_NETIF_HWADDRHINT */
+    /* queue on destination Ethernet address belonging to ipaddr */
+    return etharp_query(netif, ipaddr, q);
+  }
+
+  /* continuation for multicast/broadcast destinations */
+  /* obtain source Ethernet address of the given interface */
+  /* send packet directly on the link */
+  return etharp_send_ip(netif, q, (struct eth_addr*)(netif->hwaddr), dest);
+}
+
+/**
+ * Send an ARP request for the given IP address and/or queue a packet.
+ *
+ * If the IP address was not yet in the cache, a pending ARP cache entry
+ * is added and an ARP request is sent for the given address. The packet
+ * is queued on this entry.
+ *
+ * If the IP address was already pending in the cache, a new ARP request
+ * is sent for the given address. The packet is queued on this entry.
+ *
+ * If the IP address was already stable in the cache, and a packet is
+ * given, it is directly sent and no ARP request is sent out. 
+ * 
+ * If the IP address was already stable in the cache, and no packet is
+ * given, an ARP request is sent out.
+ * 
+ * @param netif The lwIP network interface on which ipaddr
+ * must be queried for.
+ * @param ipaddr The IP address to be resolved.
+ * @param q If non-NULL, a pbuf that must be delivered to the IP address.
+ * q is not freed by this function.
+ *
+ * @note q must only be ONE packet, not a packet queue!
+ *
+ * @return
+ * - ERR_BUF Could not make room for Ethernet header.
+ * - ERR_MEM Hardware address unknown, and no more ARP entries available
+ *   to query for address or queue the packet.
+ * - ERR_MEM Could not queue packet due to memory shortage.
+ * - ERR_RTE No route to destination (no gateway to external networks).
+ * - ERR_ARG Non-unicast address given, those will not appear in ARP cache.
+ *
+ */
+err_t
+etharp_query(struct netif *netif, ip_addr_t *ipaddr, struct pbuf *q)
+{
+  struct eth_addr * srcaddr = (struct eth_addr *)netif->hwaddr;
+  err_t result = ERR_MEM;
+  s8_t i; /* ARP entry index */
+
+  /* non-unicast address? */
+  if (ip_addr_isbroadcast(ipaddr, netif) ||
+      ip_addr_ismulticast(ipaddr) ||
+      ip_addr_isany(ipaddr)) {
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: will not add non-unicast IP address to ARP cache\n"));
+    return ERR_ARG;
+  }
+
+  /* find entry in ARP cache, ask to create entry if queueing packet */
+  i = find_entry(ipaddr, ETHARP_FLAG_TRY_HARD);
+
+  /* could not find or create entry? */
+  if (i < 0) {
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: could not create ARP entry\n"));
+    if (q) {
+      LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: packet dropped\n"));
+      ETHARP_STATS_INC(etharp.memerr);
+    }
+    return (err_t)i;
+  }
+
+  /* mark a fresh entry as pending (we just sent a request) */
+  if (arp_table[i].state == ETHARP_STATE_EMPTY) {
+    arp_table[i].state = ETHARP_STATE_PENDING;
+  }
+
+  /* { i is either a STABLE or (new or existing) PENDING entry } */
+  LWIP_ASSERT("arp_table[i].state == PENDING or STABLE",
+  ((arp_table[i].state == ETHARP_STATE_PENDING) ||
+   (arp_table[i].state == ETHARP_STATE_STABLE)));
+
+  /* do we have a pending entry? or an implicit query request? */
+  if ((arp_table[i].state == ETHARP_STATE_PENDING) || (q == NULL)) {
+    /* try to resolve it; send out ARP request */
+    result = etharp_request(netif, ipaddr);
+    if (result != ERR_OK) {
+      /* ARP request couldn't be sent */
+      /* We don't re-send arp request in etharp_tmr, but we still queue packets,
+         since this failure could be temporary, and the next packet calling
+         etharp_query again could lead to sending the queued packets. */
+    }
+    if (q == NULL) {
+      return result;
+    }
+  }
+
+  /* packet given? */
+  LWIP_ASSERT("q != NULL", q != NULL);
+  /* stable entry? */
+  if (arp_table[i].state == ETHARP_STATE_STABLE) {
+    /* we have a valid IP->Ethernet address mapping */
+    ETHARP_SET_HINT(netif, i);
+    /* send the packet */
+    result = etharp_send_ip(netif, q, srcaddr, &(arp_table[i].ethaddr));
+  /* pending entry? (either just created or already pending */
+  } else if (arp_table[i].state == ETHARP_STATE_PENDING) {
+    /* entry is still pending, queue the given packet 'q' */
+    struct pbuf *p;
+    int copy_needed = 0;
+    /* IF q includes a PBUF_REF, PBUF_POOL or PBUF_RAM, we have no choice but
+     * to copy the whole queue into a new PBUF_RAM (see bug #11400) 
+     * PBUF_ROMs can be left as they are, since ROM must not get changed. */
+    p = q;
+    while (p) {
+      LWIP_ASSERT("no packet queues allowed!", (p->len != p->tot_len) || (p->next == 0));
+      if(p->type != PBUF_ROM) {
+        copy_needed = 1;
+        break;
+      }
+      p = p->next;
+    }
+    if(copy_needed) {
+      /* copy the whole packet into new pbufs */
+      p = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_RAM);
+      if(p != NULL) {
+        if (pbuf_copy(p, q) != ERR_OK) {
+          pbuf_free(p);
+          p = NULL;
+        }
+      }
+    } else {
+      /* referencing the old pbuf is enough */
+      p = q;
+      pbuf_ref(p);
+    }
+    /* packet could be taken over? */
+    if (p != NULL) {
+      /* queue packet ... */
+#if ARP_QUEUEING
+      struct etharp_q_entry *new_entry;
+      /* allocate a new arp queue entry */
+      new_entry = (struct etharp_q_entry *)memp_malloc(MEMP_ARP_QUEUE);
+      if (new_entry != NULL) {
+        new_entry->next = 0;
+        new_entry->p = p;
+        if(arp_table[i].q != NULL) {
+          /* queue was already existent, append the new entry to the end */
+          struct etharp_q_entry *r;
+          r = arp_table[i].q;
+          while (r->next != NULL) {
+            r = r->next;
+          }
+          r->next = new_entry;
+        } else {
+          /* queue did not exist, first item in queue */
+          arp_table[i].q = new_entry;
+        }
+        LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: queued packet %p on ARP entry %"S16_F"\n", (void *)q, (s16_t)i));
+        result = ERR_OK;
+      } else {
+        /* the pool MEMP_ARP_QUEUE is empty */
+        pbuf_free(p);
+        LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: could not queue a copy of PBUF_REF packet %p (out of memory)\n", (void *)q));
+        result = ERR_MEM;
+      }
+#else /* ARP_QUEUEING */
+      /* always queue one packet per ARP request only, freeing a previously queued packet */
+      if (arp_table[i].q != NULL) {
+        LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: dropped previously queued packet %p for ARP entry %"S16_F"\n", (void *)q, (s16_t)i));
+        pbuf_free(arp_table[i].q);
+      }
+      arp_table[i].q = p;
+      result = ERR_OK;
+      LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: queued packet %p on ARP entry %"S16_F"\n", (void *)q, (s16_t)i));
+#endif /* ARP_QUEUEING */
+    } else {
+      ETHARP_STATS_INC(etharp.memerr);
+      LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: could not queue a copy of PBUF_REF packet %p (out of memory)\n", (void *)q));
+      result = ERR_MEM;
+    }
+  }
+  return result;
+}
+
+/**
+ * Send a raw ARP packet (opcode and all addresses can be modified)
+ *
+ * @param netif the lwip network interface on which to send the ARP packet
+ * @param ethsrc_addr the source MAC address for the ethernet header
+ * @param ethdst_addr the destination MAC address for the ethernet header
+ * @param hwsrc_addr the source MAC address for the ARP protocol header
+ * @param ipsrc_addr the source IP address for the ARP protocol header
+ * @param hwdst_addr the destination MAC address for the ARP protocol header
+ * @param ipdst_addr the destination IP address for the ARP protocol header
+ * @param opcode the type of the ARP packet
+ * @return ERR_OK if the ARP packet has been sent
+ *         ERR_MEM if the ARP packet couldn't be allocated
+ *         any other err_t on failure
+ */
+#if !LWIP_AUTOIP
+static
+#endif /* LWIP_AUTOIP */
+err_t
+etharp_raw(struct netif *netif, const struct eth_addr *ethsrc_addr,
+           const struct eth_addr *ethdst_addr,
+           const struct eth_addr *hwsrc_addr, const ip_addr_t *ipsrc_addr,
+           const struct eth_addr *hwdst_addr, const ip_addr_t *ipdst_addr,
+           const u16_t opcode)
+{
+  struct pbuf *p;
+  err_t result = ERR_OK;
+  struct eth_hdr *ethhdr;
+  struct etharp_hdr *hdr;
+#if LWIP_AUTOIP
+  const u8_t * ethdst_hwaddr;
+#endif /* LWIP_AUTOIP */
+
+  /* allocate a pbuf for the outgoing ARP request packet */
+  p = pbuf_alloc(PBUF_RAW, SIZEOF_ETHARP_PACKET, PBUF_RAM);
+  /* could allocate a pbuf for an ARP request? */
+  if (p == NULL) {
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
+      ("etharp_raw: could not allocate pbuf for ARP request.\n"));
+    ETHARP_STATS_INC(etharp.memerr);
+    return ERR_MEM;
+  }
+  LWIP_ASSERT("check that first pbuf can hold struct etharp_hdr",
+              (p->len >= SIZEOF_ETHARP_PACKET));
+
+  ethhdr = (struct eth_hdr *)p->payload;
+  hdr = (struct etharp_hdr *)((u8_t*)ethhdr + SIZEOF_ETH_HDR);
+  LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_raw: sending raw ARP packet.\n"));
+  hdr->opcode = htons(opcode);
+
+  LWIP_ASSERT("netif->hwaddr_len must be the same as ETHARP_HWADDR_LEN for etharp!",
+              (netif->hwaddr_len == ETHARP_HWADDR_LEN));
+#if LWIP_AUTOIP
+  /* If we are using Link-Local, all ARP packets that contain a Link-Local
+   * 'sender IP address' MUST be sent using link-layer broadcast instead of
+   * link-layer unicast. (See RFC3927 Section 2.5, last paragraph) */
+  ethdst_hwaddr = ip_addr_islinklocal(ipsrc_addr) ? (u8_t*)(ethbroadcast.addr) : ethdst_addr->addr;
+#endif /* LWIP_AUTOIP */
+  /* Write the ARP MAC-Addresses */
+  ETHADDR16_COPY(&hdr->shwaddr, hwsrc_addr);
+  ETHADDR16_COPY(&hdr->dhwaddr, hwdst_addr);
+  /* Write the Ethernet MAC-Addresses */
+#if LWIP_AUTOIP
+  ETHADDR16_COPY(&ethhdr->dest, ethdst_hwaddr);
+#else  /* LWIP_AUTOIP */
+  ETHADDR16_COPY(&ethhdr->dest, ethdst_addr);
+#endif /* LWIP_AUTOIP */
+  ETHADDR16_COPY(&ethhdr->src, ethsrc_addr);
+  /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without
+   * structure packing. */ 
+  IPADDR2_COPY(&hdr->sipaddr, ipsrc_addr);
+  IPADDR2_COPY(&hdr->dipaddr, ipdst_addr);
+
+  hdr->hwtype = PP_HTONS(HWTYPE_ETHERNET);
+  hdr->proto = PP_HTONS(ETHTYPE_IP);
+  /* set hwlen and protolen */
+  hdr->hwlen = ETHARP_HWADDR_LEN;
+  hdr->protolen = sizeof(ip_addr_t);
+
+  ethhdr->type = PP_HTONS(ETHTYPE_ARP);
+  /* send ARP query */
+  result = netif->linkoutput(netif, p);
+  ETHARP_STATS_INC(etharp.xmit);
+  /* free ARP query packet */
+  pbuf_free(p);
+  p = NULL;
+  /* could not allocate pbuf for ARP request */
+
+  return result;
+}
+
+/**
+ * Send an ARP request packet asking for ipaddr.
+ *
+ * @param netif the lwip network interface on which to send the request
+ * @param ipaddr the IP address for which to ask
+ * @return ERR_OK if the request has been sent
+ *         ERR_MEM if the ARP packet couldn't be allocated
+ *         any other err_t on failure
+ */
+err_t
+etharp_request(struct netif *netif, ip_addr_t *ipaddr)
+{
+  LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_request: sending ARP request.\n"));
+  return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, &ethbroadcast,
+                    (struct eth_addr *)netif->hwaddr, &netif->ip_addr, &ethzero,
+                    ipaddr, ARP_REQUEST);
+}
+#endif /* LWIP_ARP */
+
+/**
+ * Process received ethernet frames. Using this function instead of directly
+ * calling ip_input and passing ARP frames through etharp in ethernetif_input,
+ * the ARP cache is protected from concurrent access.
+ *
+ * @param p the recevied packet, p->payload pointing to the ethernet header
+ * @param netif the network interface on which the packet was received
+ */
+err_t
+ethernet_input(struct pbuf *p, struct netif *netif)
+{
+  struct eth_hdr* ethhdr;
+  u16_t type;
+  s16_t ip_hdr_offset = SIZEOF_ETH_HDR;
+
+  if (p->len <= SIZEOF_ETH_HDR) {
+    /* a packet with only an ethernet header (or less) is not valid for us */
+    ETHARP_STATS_INC(etharp.proterr);
+    ETHARP_STATS_INC(etharp.drop);
+    goto free_and_return;
+  }
+
+  /* points to packet payload, which starts with an Ethernet header */
+  ethhdr = (struct eth_hdr *)p->payload;
+  LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE,
+    ("ethernet_input: dest:%"X8_F":%"X8_F":%"X8_F":%"X8_F":%"X8_F":%"X8_F", src:%"X8_F":%"X8_F":%"X8_F":%"X8_F":%"X8_F":%"X8_F", type:%"X16_F"\n",
+     (unsigned)ethhdr->dest.addr[0], (unsigned)ethhdr->dest.addr[1], (unsigned)ethhdr->dest.addr[2],
+     (unsigned)ethhdr->dest.addr[3], (unsigned)ethhdr->dest.addr[4], (unsigned)ethhdr->dest.addr[5],
+     (unsigned)ethhdr->src.addr[0], (unsigned)ethhdr->src.addr[1], (unsigned)ethhdr->src.addr[2],
+     (unsigned)ethhdr->src.addr[3], (unsigned)ethhdr->src.addr[4], (unsigned)ethhdr->src.addr[5],
+     (unsigned)htons(ethhdr->type)));
+
+  type = ethhdr->type;
+#if ETHARP_SUPPORT_VLAN
+  if (type == PP_HTONS(ETHTYPE_VLAN)) {
+    struct eth_vlan_hdr *vlan = (struct eth_vlan_hdr*)(((char*)ethhdr) + SIZEOF_ETH_HDR);
+    if (p->len <= SIZEOF_ETH_HDR + SIZEOF_VLAN_HDR) {
+      /* a packet with only an ethernet/vlan header (or less) is not valid for us */
+      ETHARP_STATS_INC(etharp.proterr);
+      ETHARP_STATS_INC(etharp.drop);
+      goto free_and_return;
+    }
+#ifdef ETHARP_VLAN_CHECK /* if not, allow all VLANs */
+    if (VLAN_ID(vlan) != ETHARP_VLAN_CHECK) {
+      /* silently ignore this packet: not for our VLAN */
+      pbuf_free(p);
+      return ERR_OK;
+    }
+#endif /* ETHARP_VLAN_CHECK */
+    type = vlan->tpid;
+    ip_hdr_offset = SIZEOF_ETH_HDR + SIZEOF_VLAN_HDR;
+  }
+#endif /* ETHARP_SUPPORT_VLAN */
+
+#if LWIP_ARP_FILTER_NETIF
+  netif = LWIP_ARP_FILTER_NETIF_FN(p, netif, htons(type));
+#endif /* LWIP_ARP_FILTER_NETIF*/
+
+  switch (type) {
+#if LWIP_ARP
+    /* IP packet? */
+    case PP_HTONS(ETHTYPE_IP):
+      if (!(netif->flags & NETIF_FLAG_ETHARP)) {
+        goto free_and_return;
+      }
+#if ETHARP_TRUST_IP_MAC
+      /* update ARP table */
+      etharp_ip_input(netif, p);
+#endif /* ETHARP_TRUST_IP_MAC */
+      /* skip Ethernet header */
+      if(pbuf_header(p, -ip_hdr_offset)) {
+        LWIP_ASSERT("Can't move over header in packet", 0);
+        goto free_and_return;
+      } else {
+        /* pass to IP layer */
+        ip_input(p, netif);
+      }
+      break;
+      
+    case PP_HTONS(ETHTYPE_ARP):
+      if (!(netif->flags & NETIF_FLAG_ETHARP)) {
+        goto free_and_return;
+      }
+      /* pass p to ARP module */
+      etharp_arp_input(netif, (struct eth_addr*)(netif->hwaddr), p);
+      break;
+#endif /* LWIP_ARP */
+#if PPPOE_SUPPORT
+    case PP_HTONS(ETHTYPE_PPPOEDISC): /* PPP Over Ethernet Discovery Stage */
+      pppoe_disc_input(netif, p);
+      break;
+
+    case PP_HTONS(ETHTYPE_PPPOE): /* PPP Over Ethernet Session Stage */
+      pppoe_data_input(netif, p);
+      break;
+#endif /* PPPOE_SUPPORT */
+
+    default:
+      ETHARP_STATS_INC(etharp.proterr);
+      ETHARP_STATS_INC(etharp.drop);
+      goto free_and_return;
+  }
+
+  /* This means the pbuf is freed or consumed,
+     so the caller doesn't have to free it again */
+  return ERR_OK;
+
+free_and_return:
+  pbuf_free(p);
+  return ERR_OK;
+}
+#endif /* LWIP_ARP || LWIP_ETHERNET */
diff --git a/core/lwip/src/netif/ethernetif.c b/core/lwip/src/netif/ethernetif.c
new file mode 100644
index 00000000..a5b7d990
--- /dev/null
+++ b/core/lwip/src/netif/ethernetif.c
@@ -0,0 +1,318 @@
+/**
+ * @file
+ * Ethernet Interface Skeleton
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+/*
+ * This file is a skeleton for developing Ethernet network interface
+ * drivers for lwIP. Add code to the low_level functions and do a
+ * search-and-replace for the word "ethernetif" to replace it with
+ * something that better describes your network interface.
+ */
+
+#include "lwip/opt.h"
+
+#if 0 /* don't build, this is only a skeleton, see previous comment */
+
+#include "lwip/def.h"
+#include "lwip/mem.h"
+#include "lwip/pbuf.h"
+#include "lwip/sys.h"
+#include <lwip/stats.h>
+#include <lwip/snmp.h>
+#include "netif/etharp.h"
+#include "netif/ppp_oe.h"
+
+/* Define those to better describe your network interface. */
+#define IFNAME0 'e'
+#define IFNAME1 'n'
+
+/**
+ * Helper struct to hold private data used to operate your ethernet interface.
+ * Keeping the ethernet address of the MAC in this struct is not necessary
+ * as it is already kept in the struct netif.
+ * But this is only an example, anyway...
+ */
+struct ethernetif {
+  struct eth_addr *ethaddr;
+  /* Add whatever per-interface state that is needed here. */
+};
+
+/* Forward declarations. */
+static void  ethernetif_input(struct netif *netif);
+
+/**
+ * In this function, the hardware should be initialized.
+ * Called from ethernetif_init().
+ *
+ * @param netif the already initialized lwip network interface structure
+ *        for this ethernetif
+ */
+static void
+low_level_init(struct netif *netif)
+{
+  struct ethernetif *ethernetif = netif->state;
+  
+  /* set MAC hardware address length */
+  netif->hwaddr_len = ETHARP_HWADDR_LEN;
+
+  /* set MAC hardware address */
+  netif->hwaddr[0] = ;
+  ...
+  netif->hwaddr[5] = ;
+
+  /* maximum transfer unit */
+  netif->mtu = 1500;
+  
+  /* device capabilities */
+  /* don't set NETIF_FLAG_ETHARP if this device is not an ethernet one */
+  netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_LINK_UP;
+ 
+  /* Do whatever else is needed to initialize interface. */  
+}
+
+/**
+ * This function should do the actual transmission of the packet. The packet is
+ * contained in the pbuf that is passed to the function. This pbuf
+ * might be chained.
+ *
+ * @param netif the lwip network interface structure for this ethernetif
+ * @param p the MAC packet to send (e.g. IP packet including MAC addresses and type)
+ * @return ERR_OK if the packet could be sent
+ *         an err_t value if the packet couldn't be sent
+ *
+ * @note Returning ERR_MEM here if a DMA queue of your MAC is full can lead to
+ *       strange results. You might consider waiting for space in the DMA queue
+ *       to become availale since the stack doesn't retry to send a packet
+ *       dropped because of memory failure (except for the TCP timers).
+ */
+
+static err_t
+low_level_output(struct netif *netif, struct pbuf *p)
+{
+  struct ethernetif *ethernetif = netif->state;
+  struct pbuf *q;
+
+  initiate transfer();
+  
+#if ETH_PAD_SIZE
+  pbuf_header(p, -ETH_PAD_SIZE); /* drop the padding word */
+#endif
+
+  for(q = p; q != NULL; q = q->next) {
+    /* Send the data from the pbuf to the interface, one pbuf at a
+       time. The size of the data in each pbuf is kept in the ->len
+       variable. */
+    send data from(q->payload, q->len);
+  }
+
+  signal that packet should be sent();
+
+#if ETH_PAD_SIZE
+  pbuf_header(p, ETH_PAD_SIZE); /* reclaim the padding word */
+#endif
+  
+  LINK_STATS_INC(link.xmit);
+
+  return ERR_OK;
+}
+
+/**
+ * Should allocate a pbuf and transfer the bytes of the incoming
+ * packet from the interface into the pbuf.
+ *
+ * @param netif the lwip network interface structure for this ethernetif
+ * @return a pbuf filled with the received packet (including MAC header)
+ *         NULL on memory error
+ */
+static struct pbuf *
+low_level_input(struct netif *netif)
+{
+  struct ethernetif *ethernetif = netif->state;
+  struct pbuf *p, *q;
+  u16_t len;
+
+  /* Obtain the size of the packet and put it into the "len"
+     variable. */
+  len = ;
+
+#if ETH_PAD_SIZE
+  len += ETH_PAD_SIZE; /* allow room for Ethernet padding */
+#endif
+
+  /* We allocate a pbuf chain of pbufs from the pool. */
+  p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
+  
+  if (p != NULL) {
+
+#if ETH_PAD_SIZE
+    pbuf_header(p, -ETH_PAD_SIZE); /* drop the padding word */
+#endif
+
+    /* We iterate over the pbuf chain until we have read the entire
+     * packet into the pbuf. */
+    for(q = p; q != NULL; q = q->next) {
+      /* Read enough bytes to fill this pbuf in the chain. The
+       * available data in the pbuf is given by the q->len
+       * variable.
+       * This does not necessarily have to be a memcpy, you can also preallocate
+       * pbufs for a DMA-enabled MAC and after receiving truncate it to the
+       * actually received size. In this case, ensure the tot_len member of the
+       * pbuf is the sum of the chained pbuf len members.
+       */
+      read data into(q->payload, q->len);
+    }
+    acknowledge that packet has been read();
+
+#if ETH_PAD_SIZE
+    pbuf_header(p, ETH_PAD_SIZE); /* reclaim the padding word */
+#endif
+
+    LINK_STATS_INC(link.recv);
+  } else {
+    drop packet();
+    LINK_STATS_INC(link.memerr);
+    LINK_STATS_INC(link.drop);
+  }
+
+  return p;  
+}
+
+/**
+ * This function should be called when a packet is ready to be read
+ * from the interface. It uses the function low_level_input() that
+ * should handle the actual reception of bytes from the network
+ * interface. Then the type of the received packet is determined and
+ * the appropriate input function is called.
+ *
+ * @param netif the lwip network interface structure for this ethernetif
+ */
+static void
+ethernetif_input(struct netif *netif)
+{
+  struct ethernetif *ethernetif;
+  struct eth_hdr *ethhdr;
+  struct pbuf *p;
+
+  ethernetif = netif->state;
+
+  /* move received packet into a new pbuf */
+  p = low_level_input(netif);
+  /* no packet could be read, silently ignore this */
+  if (p == NULL) return;
+  /* points to packet payload, which starts with an Ethernet header */
+  ethhdr = p->payload;
+
+  switch (htons(ethhdr->type)) {
+  /* IP or ARP packet? */
+  case ETHTYPE_IP:
+  case ETHTYPE_ARP:
+#if PPPOE_SUPPORT
+  /* PPPoE packet? */
+  case ETHTYPE_PPPOEDISC:
+  case ETHTYPE_PPPOE:
+#endif /* PPPOE_SUPPORT */
+    /* full packet send to tcpip_thread to process */
+    if (netif->input(p, netif)!=ERR_OK)
+     { LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_input: IP input error\n"));
+       pbuf_free(p);
+       p = NULL;
+     }
+    break;
+
+  default:
+    pbuf_free(p);
+    p = NULL;
+    break;
+  }
+}
+
+/**
+ * Should be called at the beginning of the program to set up the
+ * network interface. It calls the function low_level_init() to do the
+ * actual setup of the hardware.
+ *
+ * This function should be passed as a parameter to netif_add().
+ *
+ * @param netif the lwip network interface structure for this ethernetif
+ * @return ERR_OK if the loopif is initialized
+ *         ERR_MEM if private data couldn't be allocated
+ *         any other err_t on error
+ */
+err_t
+ethernetif_init(struct netif *netif)
+{
+  struct ethernetif *ethernetif;
+
+  LWIP_ASSERT("netif != NULL", (netif != NULL));
+    
+  ethernetif = mem_malloc(sizeof(struct ethernetif));
+  if (ethernetif == NULL) {
+    LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_init: out of memory\n"));
+    return ERR_MEM;
+  }
+
+#if LWIP_NETIF_HOSTNAME
+  /* Initialize interface hostname */
+  netif->hostname = "lwip";
+#endif /* LWIP_NETIF_HOSTNAME */
+
+  /*
+   * Initialize the snmp variables and counters inside the struct netif.
+   * The last argument should be replaced with your link speed, in units
+   * of bits per second.
+   */
+  NETIF_INIT_SNMP(netif, snmp_ifType_ethernet_csmacd, LINK_SPEED_OF_YOUR_NETIF_IN_BPS);
+
+  netif->state = ethernetif;
+  netif->name[0] = IFNAME0;
+  netif->name[1] = IFNAME1;
+  /* We directly use etharp_output() here to save a function call.
+   * You can instead declare your own function an call etharp_output()
+   * from it if you have to do some checks before sending (e.g. if link
+   * is available...) */
+  netif->output = etharp_output;
+  netif->linkoutput = low_level_output;
+  
+  ethernetif->ethaddr = (struct eth_addr *)&(netif->hwaddr[0]);
+  
+  /* initialize the hardware */
+  low_level_init(netif);
+
+  return ERR_OK;
+}
+
+#endif /* 0 */
diff --git a/core/lwip/src/netif/ppp/auth.c b/core/lwip/src/netif/ppp/auth.c
new file mode 100644
index 00000000..c3c49d22
--- /dev/null
+++ b/core/lwip/src/netif/ppp/auth.c
@@ -0,0 +1,1334 @@
+/*****************************************************************************
+* auth.c - Network Authentication and Phase Control program file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* Copyright (c) 1997 by Global Election Systems Inc.  All rights reserved.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 97-12-08 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
+*   Ported from public pppd code.
+*****************************************************************************/
+/*
+ * auth.c - PPP authentication and phase control.
+ *
+ * Copyright (c) 1993 The Australian National University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by the Australian National University.  The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * Copyright (c) 1989 Carnegie Mellon University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Carnegie Mellon University.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#include "lwip/opt.h"
+
+#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
+
+#include "ppp.h"
+#include "pppdebug.h"
+
+#include "fsm.h"
+#include "lcp.h"
+#include "pap.h"
+#include "chap.h"
+#include "auth.h"
+#include "ipcp.h"
+
+#if CBCP_SUPPORT
+#include "cbcp.h"
+#endif /* CBCP_SUPPORT */
+
+#include "lwip/inet.h"
+
+#include <string.h>
+
+#if 0 /* UNUSED */
+/* Bits in scan_authfile return value */
+#define NONWILD_SERVER  1
+#define NONWILD_CLIENT  2
+
+#define ISWILD(word)  (word[0] == '*' && word[1] == 0)
+#endif /* UNUSED */
+
+#if PAP_SUPPORT || CHAP_SUPPORT
+/* The name by which the peer authenticated itself to us. */
+static char peer_authname[MAXNAMELEN];
+#endif /* PAP_SUPPORT || CHAP_SUPPORT */
+
+/* Records which authentication operations haven't completed yet. */
+static int auth_pending[NUM_PPP];
+
+/* Set if we have successfully called plogin() */
+static int logged_in;
+
+/* Set if we have run the /etc/ppp/auth-up script. */
+static int did_authup; /* @todo, we don't need this in lwip*/
+
+/* List of addresses which the peer may use. */
+static struct wordlist *addresses[NUM_PPP];
+
+#if 0 /* UNUSED */
+/* Wordlist giving addresses which the peer may use
+   without authenticating itself. */
+static struct wordlist *noauth_addrs;
+
+/* Extra options to apply, from the secrets file entry for the peer. */
+static struct wordlist *extra_options;
+#endif /* UNUSED */
+
+/* Number of network protocols which we have opened. */
+static int num_np_open;
+
+/* Number of network protocols which have come up. */
+static int num_np_up;
+
+#if PAP_SUPPORT || CHAP_SUPPORT
+/* Set if we got the contents of passwd[] from the pap-secrets file. */
+static int passwd_from_file;
+#endif /* PAP_SUPPORT || CHAP_SUPPORT */
+
+#if 0 /* UNUSED */
+/* Set if we require authentication only because we have a default route. */
+static bool default_auth;
+
+/* Hook to enable a plugin to control the idle time limit */
+int (*idle_time_hook) __P((struct ppp_idle *)) = NULL;
+
+/* Hook for a plugin to say whether we can possibly authenticate any peer */
+int (*pap_check_hook) __P((void)) = NULL;
+
+/* Hook for a plugin to check the PAP user and password */
+int (*pap_auth_hook) __P((char *user, char *passwd, char **msgp,
+        struct wordlist **paddrs,
+        struct wordlist **popts)) = NULL;
+
+/* Hook for a plugin to know about the PAP user logout */
+void (*pap_logout_hook) __P((void)) = NULL;
+
+/* Hook for a plugin to get the PAP password for authenticating us */
+int (*pap_passwd_hook) __P((char *user, char *passwd)) = NULL;
+
+/*
+ * This is used to ensure that we don't start an auth-up/down
+ * script while one is already running.
+ */
+enum script_state {
+    s_down,
+    s_up
+};
+
+static enum script_state auth_state = s_down;
+static enum script_state auth_script_state = s_down;
+static pid_t auth_script_pid = 0;
+
+/*
+ * Option variables.
+ * lwip: some of these are present in the ppp_settings structure
+ */
+bool uselogin = 0;            /* Use /etc/passwd for checking PAP */
+bool cryptpap = 0;            /* Passwords in pap-secrets are encrypted */
+bool refuse_pap = 0;          /* Don't wanna auth. ourselves with PAP */
+bool refuse_chap = 0;         /* Don't wanna auth. ourselves with CHAP */
+bool usehostname = 0;         /* Use hostname for our_name */
+bool auth_required = 0;       /* Always require authentication from peer */
+bool allow_any_ip = 0;        /* Allow peer to use any IP address */
+bool explicit_remote = 0;     /* User specified explicit remote name */
+char remote_name[MAXNAMELEN]; /* Peer's name for authentication */
+
+#endif /* UNUSED */
+
+/* Bits in auth_pending[] */
+#define PAP_WITHPEER    1
+#define PAP_PEER        2
+#define CHAP_WITHPEER   4
+#define CHAP_PEER       8
+
+/* @todo, move this somewhere */
+/* Used for storing a sequence of words.  Usually malloced. */
+struct wordlist {
+  struct wordlist *next;
+  char        word[1];
+};
+
+
+extern char *crypt (const char *, const char *);
+
+/* Prototypes for procedures local to this file. */
+
+static void network_phase (int);
+static void check_idle (void *);
+static void connect_time_expired (void *);
+#if 0
+static int  plogin (char *, char *, char **, int *);
+#endif
+static void plogout (void);
+static int  null_login (int);
+static int  get_pap_passwd (int, char *, char *);
+static int  have_pap_secret (void);
+static int  have_chap_secret (char *, char *, u32_t);
+static int  ip_addr_check (u32_t, struct wordlist *);
+
+#if 0 /* PAP_SUPPORT || CHAP_SUPPORT */
+static int  scan_authfile (FILE *, char *, char *, char *,
+             struct wordlist **, struct wordlist **,
+             char *);
+static void free_wordlist (struct wordlist *);
+static void auth_script (char *);
+static void auth_script_done (void *);
+static void set_allowed_addrs (int unit, struct wordlist *addrs);
+static int  some_ip_ok (struct wordlist *);
+static int  setupapfile (char **);
+static int  privgroup (char **);
+static int  set_noauth_addr (char **);
+static void check_access (FILE *, char *);
+#endif /* 0 */ /* PAP_SUPPORT || CHAP_SUPPORT */
+
+#if 0 /* UNUSED */
+/*
+ * Authentication-related options.
+ */
+option_t auth_options[] = {
+    { "require-pap", o_bool, &lcp_wantoptions[0].neg_upap,
+      "Require PAP authentication from peer", 1, &auth_required },
+    { "+pap", o_bool, &lcp_wantoptions[0].neg_upap,
+      "Require PAP authentication from peer", 1, &auth_required },
+    { "refuse-pap", o_bool, &refuse_pap,
+      "Don't agree to auth to peer with PAP", 1 },
+    { "-pap", o_bool, &refuse_pap,
+      "Don't allow PAP authentication with peer", 1 },
+    { "require-chap", o_bool, &lcp_wantoptions[0].neg_chap,
+      "Require CHAP authentication from peer", 1, &auth_required },
+    { "+chap", o_bool, &lcp_wantoptions[0].neg_chap,
+      "Require CHAP authentication from peer", 1, &auth_required },
+    { "refuse-chap", o_bool, &refuse_chap,
+      "Don't agree to auth to peer with CHAP", 1 },
+    { "-chap", o_bool, &refuse_chap,
+      "Don't allow CHAP authentication with peer", 1 },
+    { "name", o_string, our_name,
+      "Set local name for authentication",
+      OPT_PRIV|OPT_STATIC, NULL, MAXNAMELEN },
+    { "user", o_string, user,
+      "Set name for auth with peer", OPT_STATIC, NULL, MAXNAMELEN },
+    { "usehostname", o_bool, &usehostname,
+      "Must use hostname for authentication", 1 },
+    { "remotename", o_string, remote_name,
+      "Set remote name for authentication", OPT_STATIC,
+      &explicit_remote, MAXNAMELEN },
+    { "auth", o_bool, &auth_required,
+      "Require authentication from peer", 1 },
+    { "noauth", o_bool, &auth_required,
+      "Don't require peer to authenticate", OPT_PRIV, &allow_any_ip },
+    {  "login", o_bool, &uselogin,
+      "Use system password database for PAP", 1 },
+    { "papcrypt", o_bool, &cryptpap,
+      "PAP passwords are encrypted", 1 },
+    { "+ua", o_special, (void *)setupapfile,
+      "Get PAP user and password from file" },
+    { "password", o_string, passwd,
+      "Password for authenticating us to the peer", OPT_STATIC,
+      NULL, MAXSECRETLEN },
+    { "privgroup", o_special, (void *)privgroup,
+      "Allow group members to use privileged options", OPT_PRIV },
+    { "allow-ip", o_special, (void *)set_noauth_addr,
+      "Set IP address(es) which can be used without authentication",
+      OPT_PRIV },
+    { NULL }
+};
+#endif /* UNUSED */
+#if 0 /* UNUSED */
+/*
+ * setupapfile - specifies UPAP info for authenticating with peer.
+ */
+static int
+setupapfile(char **argv)
+{
+    FILE * ufile;
+    int l;
+
+    lcp_allowoptions[0].neg_upap = 1;
+
+    /* open user info file */
+    seteuid(getuid());
+    ufile = fopen(*argv, "r");
+    seteuid(0);
+    if (ufile == NULL) {
+      option_error("unable to open user login data file %s", *argv);
+      return 0;
+    }
+    check_access(ufile, *argv);
+
+    /* get username */
+    if (fgets(user, MAXNAMELEN - 1, ufile) == NULL
+        || fgets(passwd, MAXSECRETLEN - 1, ufile) == NULL){
+      option_error("unable to read user login data file %s", *argv);
+      return 0;
+    }
+    fclose(ufile);
+
+    /* get rid of newlines */
+    l = strlen(user);
+    if (l > 0 && user[l-1] == '\n')
+      user[l-1] = 0;
+    l = strlen(passwd);
+    if (l > 0 && passwd[l-1] == '\n')
+      passwd[l-1] = 0;
+
+    return (1);
+}
+#endif /* UNUSED */
+
+#if 0 /* UNUSED */
+/*
+ * privgroup - allow members of the group to have privileged access.
+ */
+static int
+privgroup(char **argv)
+{
+    struct group *g;
+    int i;
+
+    g = getgrnam(*argv);
+    if (g == 0) {
+      option_error("group %s is unknown", *argv);
+      return 0;
+    }
+    for (i = 0; i < ngroups; ++i) {
+      if (groups[i] == g->gr_gid) {
+        privileged = 1;
+        break;
+      }
+    }
+    return 1;
+}
+#endif
+
+#if 0 /* UNUSED */
+/*
+ * set_noauth_addr - set address(es) that can be used without authentication.
+ * Equivalent to specifying an entry like `"" * "" addr' in pap-secrets.
+ */
+static int
+set_noauth_addr(char **argv)
+{
+    char *addr = *argv;
+    int l = strlen(addr);
+    struct wordlist *wp;
+
+    wp = (struct wordlist *) malloc(sizeof(struct wordlist) + l + 1);
+    if (wp == NULL)
+      novm("allow-ip argument");
+    wp->word = (char *) (wp + 1);
+    wp->next = noauth_addrs;
+    BCOPY(addr, wp->word, l);
+    noauth_addrs = wp;
+    return 1;
+}
+#endif /* UNUSED */
+
+/*
+ * An Open on LCP has requested a change from Dead to Establish phase.
+ * Do what's necessary to bring the physical layer up.
+ */
+void
+link_required(int unit)
+{
+  LWIP_UNUSED_ARG(unit);
+
+  AUTHDEBUG(LOG_INFO, ("link_required: %d\n", unit));
+}
+
+/*
+ * LCP has terminated the link; go to the Dead phase and take the
+ * physical layer down.
+ */
+void
+link_terminated(int unit)
+{
+  AUTHDEBUG(LOG_INFO, ("link_terminated: %d\n", unit));
+  if (lcp_phase[unit] == PHASE_DEAD) {
+    return;
+  }
+  if (logged_in) {
+    plogout();
+  }
+  lcp_phase[unit] = PHASE_DEAD;
+  AUTHDEBUG(LOG_NOTICE, ("Connection terminated.\n"));
+  pppLinkTerminated(unit);
+}
+
+/*
+ * LCP has gone down; it will either die or try to re-establish.
+ */
+void
+link_down(int unit)
+{
+  int i;
+  struct protent *protp;
+
+  AUTHDEBUG(LOG_INFO, ("link_down: %d\n", unit));
+
+  if (did_authup) {
+    /* XXX Do link down processing. */
+    did_authup = 0;
+  }
+  for (i = 0; (protp = ppp_protocols[i]) != NULL; ++i) {
+    if (!protp->enabled_flag) {
+      continue;
+    }
+    if (protp->protocol != PPP_LCP && protp->lowerdown != NULL) {
+      (*protp->lowerdown)(unit);
+    }
+    if (protp->protocol < 0xC000 && protp->close != NULL) {
+      (*protp->close)(unit, "LCP down");
+    }
+  }
+  num_np_open = 0;  /* number of network protocols we have opened */
+  num_np_up = 0;    /* Number of network protocols which have come up */
+
+  if (lcp_phase[unit] != PHASE_DEAD) {
+    lcp_phase[unit] = PHASE_TERMINATE;
+  }
+  pppLinkDown(unit);
+}
+
+/*
+ * The link is established.
+ * Proceed to the Dead, Authenticate or Network phase as appropriate.
+ */
+void
+link_established(int unit)
+{
+  int auth;
+  int i;
+  struct protent *protp;
+  lcp_options *wo = &lcp_wantoptions[unit];
+  lcp_options *go = &lcp_gotoptions[unit];
+#if PAP_SUPPORT || CHAP_SUPPORT
+  lcp_options *ho = &lcp_hisoptions[unit];
+#endif /* PAP_SUPPORT || CHAP_SUPPORT */
+
+  AUTHDEBUG(LOG_INFO, ("link_established: unit %d; Lowering up all protocols...\n", unit));
+  /*
+   * Tell higher-level protocols that LCP is up.
+   */
+  for (i = 0; (protp = ppp_protocols[i]) != NULL; ++i) {
+    if (protp->protocol != PPP_LCP && protp->enabled_flag && protp->lowerup != NULL) {
+      (*protp->lowerup)(unit);
+    }
+  }
+  if (ppp_settings.auth_required && !(go->neg_chap || go->neg_upap)) {
+    /*
+     * We wanted the peer to authenticate itself, and it refused:
+     * treat it as though it authenticated with PAP using a username
+     * of "" and a password of "".  If that's not OK, boot it out.
+     */
+    if (!wo->neg_upap || !null_login(unit)) {
+      AUTHDEBUG(LOG_WARNING, ("peer refused to authenticate\n"));
+      lcp_close(unit, "peer refused to authenticate");
+      return;
+    }
+  }
+
+  lcp_phase[unit] = PHASE_AUTHENTICATE;
+  auth = 0;
+#if CHAP_SUPPORT
+  if (go->neg_chap) {
+    ChapAuthPeer(unit, ppp_settings.our_name, go->chap_mdtype);
+    auth |= CHAP_PEER;
+  } 
+#endif /* CHAP_SUPPORT */
+#if PAP_SUPPORT && CHAP_SUPPORT
+  else
+#endif /* PAP_SUPPORT && CHAP_SUPPORT */
+#if PAP_SUPPORT
+  if (go->neg_upap) {
+    upap_authpeer(unit);
+    auth |= PAP_PEER;
+  }
+#endif /* PAP_SUPPORT */
+#if CHAP_SUPPORT
+  if (ho->neg_chap) {
+    ChapAuthWithPeer(unit, ppp_settings.user, ho->chap_mdtype);
+    auth |= CHAP_WITHPEER;
+  }
+#endif /* CHAP_SUPPORT */
+#if PAP_SUPPORT && CHAP_SUPPORT
+  else
+#endif /* PAP_SUPPORT && CHAP_SUPPORT */
+#if PAP_SUPPORT
+  if (ho->neg_upap) {
+    if (ppp_settings.passwd[0] == 0) {
+      passwd_from_file = 1;
+      if (!get_pap_passwd(unit, ppp_settings.user, ppp_settings.passwd)) {
+        AUTHDEBUG(LOG_ERR, ("No secret found for PAP login\n"));
+      }
+    }
+    upap_authwithpeer(unit, ppp_settings.user, ppp_settings.passwd);
+    auth |= PAP_WITHPEER;
+  }
+#endif /* PAP_SUPPORT */
+  auth_pending[unit] = auth;
+
+  if (!auth) {
+    network_phase(unit);
+  }
+}
+
+/*
+ * Proceed to the network phase.
+ */
+static void
+network_phase(int unit)
+{
+  int i;
+  struct protent *protp;
+  lcp_options *go = &lcp_gotoptions[unit];
+
+  /*
+   * If the peer had to authenticate, run the auth-up script now.
+   */
+  if ((go->neg_chap || go->neg_upap) && !did_authup) {
+    /* XXX Do setup for peer authentication. */
+    did_authup = 1;
+  }
+
+#if CBCP_SUPPORT
+  /*
+   * If we negotiated callback, do it now.
+   */
+  if (go->neg_cbcp) {
+    lcp_phase[unit] = PHASE_CALLBACK;
+    (*cbcp_protent.open)(unit);
+    return;
+  }
+#endif /* CBCP_SUPPORT */
+
+  lcp_phase[unit] = PHASE_NETWORK;
+  for (i = 0; (protp = ppp_protocols[i]) != NULL; ++i) {
+    if (protp->protocol < 0xC000 && protp->enabled_flag && protp->open != NULL) {
+      (*protp->open)(unit);
+      if (protp->protocol != PPP_CCP) {
+        ++num_np_open;
+      }
+    }
+  }
+
+  if (num_np_open == 0) {
+    /* nothing to do */
+    lcp_close(0, "No network protocols running");
+  }
+}
+/* @todo: add void start_networks(void) here (pppd 2.3.11) */
+
+/*
+ * The peer has failed to authenticate himself using `protocol'.
+ */
+void
+auth_peer_fail(int unit, u16_t protocol)
+{
+  LWIP_UNUSED_ARG(protocol);
+
+  AUTHDEBUG(LOG_INFO, ("auth_peer_fail: %d proto=%X\n", unit, protocol));
+  /*
+   * Authentication failure: take the link down
+   */
+  lcp_close(unit, "Authentication failed");
+}
+
+
+#if PAP_SUPPORT || CHAP_SUPPORT
+/*
+ * The peer has been successfully authenticated using `protocol'.
+ */
+void
+auth_peer_success(int unit, u16_t protocol, char *name, int namelen)
+{
+  int pbit;
+
+  AUTHDEBUG(LOG_INFO, ("auth_peer_success: %d proto=%X\n", unit, protocol));
+  switch (protocol) {
+    case PPP_CHAP:
+      pbit = CHAP_PEER;
+      break;
+    case PPP_PAP:
+      pbit = PAP_PEER;
+      break;
+    default:
+      AUTHDEBUG(LOG_WARNING, ("auth_peer_success: unknown protocol %x\n", protocol));
+      return;
+  }
+
+  /*
+   * Save the authenticated name of the peer for later.
+   */
+  if (namelen > (int)sizeof(peer_authname) - 1) {
+    namelen = sizeof(peer_authname) - 1;
+  }
+  BCOPY(name, peer_authname, namelen);
+  peer_authname[namelen] = 0;
+  
+  /*
+   * If there is no more authentication still to be done,
+   * proceed to the network (or callback) phase.
+   */
+  if ((auth_pending[unit] &= ~pbit) == 0) {
+    network_phase(unit);
+  }
+}
+
+/*
+ * We have failed to authenticate ourselves to the peer using `protocol'.
+ */
+void
+auth_withpeer_fail(int unit, u16_t protocol)
+{
+  int errCode = PPPERR_AUTHFAIL;
+
+  LWIP_UNUSED_ARG(protocol);
+
+  AUTHDEBUG(LOG_INFO, ("auth_withpeer_fail: %d proto=%X\n", unit, protocol));
+  if (passwd_from_file) {
+    BZERO(ppp_settings.passwd, MAXSECRETLEN);
+  }
+
+  /*
+   * We've failed to authenticate ourselves to our peer.
+   * He'll probably take the link down, and there's not much
+   * we can do except wait for that.
+   */
+  pppIOCtl(unit, PPPCTLS_ERRCODE, &errCode);
+  lcp_close(unit, "Failed to authenticate ourselves to peer");
+}
+
+/*
+ * We have successfully authenticated ourselves with the peer using `protocol'.
+ */
+void
+auth_withpeer_success(int unit, u16_t protocol)
+{
+  int pbit;
+
+  AUTHDEBUG(LOG_INFO, ("auth_withpeer_success: %d proto=%X\n", unit, protocol));
+  switch (protocol) {
+    case PPP_CHAP:
+      pbit = CHAP_WITHPEER;
+      break;
+    case PPP_PAP:
+      if (passwd_from_file) {
+        BZERO(ppp_settings.passwd, MAXSECRETLEN);
+      }
+      pbit = PAP_WITHPEER;
+      break;
+    default:
+      AUTHDEBUG(LOG_WARNING, ("auth_peer_success: unknown protocol %x\n", protocol));
+      pbit = 0;
+  }
+
+  /*
+   * If there is no more authentication still being done,
+   * proceed to the network (or callback) phase.
+   */
+  if ((auth_pending[unit] &= ~pbit) == 0) {
+    network_phase(unit);
+  }
+}
+#endif /* PAP_SUPPORT || CHAP_SUPPORT */
+
+
+/*
+ * np_up - a network protocol has come up.
+ */
+void
+np_up(int unit, u16_t proto)
+{
+  LWIP_UNUSED_ARG(unit);
+  LWIP_UNUSED_ARG(proto);
+
+  AUTHDEBUG(LOG_INFO, ("np_up: %d proto=%X\n", unit, proto));
+  if (num_np_up == 0) {
+    AUTHDEBUG(LOG_INFO, ("np_up: maxconnect=%d idle_time_limit=%d\n",ppp_settings.maxconnect,ppp_settings.idle_time_limit));
+    /*
+     * At this point we consider that the link has come up successfully.
+     */
+    if (ppp_settings.idle_time_limit > 0) {
+      TIMEOUT(check_idle, NULL, ppp_settings.idle_time_limit);
+    }
+
+    /*
+     * Set a timeout to close the connection once the maximum
+     * connect time has expired.
+     */
+    if (ppp_settings.maxconnect > 0) {
+      TIMEOUT(connect_time_expired, 0, ppp_settings.maxconnect);
+    }
+  }
+  ++num_np_up;
+}
+
+/*
+ * np_down - a network protocol has gone down.
+ */
+void
+np_down(int unit, u16_t proto)
+{
+  LWIP_UNUSED_ARG(unit);
+  LWIP_UNUSED_ARG(proto);
+
+  AUTHDEBUG(LOG_INFO, ("np_down: %d proto=%X\n", unit, proto));
+  if (--num_np_up == 0 && ppp_settings.idle_time_limit > 0) {
+    UNTIMEOUT(check_idle, NULL);
+  }
+}
+
+/*
+ * np_finished - a network protocol has finished using the link.
+ */
+void
+np_finished(int unit, u16_t proto)
+{
+  LWIP_UNUSED_ARG(unit);
+  LWIP_UNUSED_ARG(proto);
+
+  AUTHDEBUG(LOG_INFO, ("np_finished: %d proto=%X\n", unit, proto));
+  if (--num_np_open <= 0) {
+    /* no further use for the link: shut up shop. */
+    lcp_close(0, "No network protocols running");
+  }
+}
+
+/*
+ * check_idle - check whether the link has been idle for long
+ * enough that we can shut it down.
+ */
+static void
+check_idle(void *arg)
+{
+  struct ppp_idle idle;
+  u_short itime;
+  
+  LWIP_UNUSED_ARG(arg);
+  if (!get_idle_time(0, &idle)) {
+    return;
+  }
+  itime = LWIP_MIN(idle.xmit_idle, idle.recv_idle);
+  if (itime >= ppp_settings.idle_time_limit) {
+    /* link is idle: shut it down. */
+    AUTHDEBUG(LOG_INFO, ("Terminating connection due to lack of activity.\n"));
+    lcp_close(0, "Link inactive");
+  } else {
+    TIMEOUT(check_idle, NULL, ppp_settings.idle_time_limit - itime);
+  }
+}
+
+/*
+ * connect_time_expired - log a message and close the connection.
+ */
+static void
+connect_time_expired(void *arg)
+{
+  LWIP_UNUSED_ARG(arg);
+
+  AUTHDEBUG(LOG_INFO, ("Connect time expired\n"));
+  lcp_close(0, "Connect time expired");   /* Close connection */
+}
+
+#if 0 /* UNUSED */
+/*
+ * auth_check_options - called to check authentication options.
+ */
+void
+auth_check_options(void)
+{
+  lcp_options *wo = &lcp_wantoptions[0];
+  int can_auth;
+  ipcp_options *ipwo = &ipcp_wantoptions[0];
+  u32_t remote;
+
+  /* Default our_name to hostname, and user to our_name */
+  if (ppp_settings.our_name[0] == 0 || ppp_settings.usehostname) {
+      strcpy(ppp_settings.our_name, ppp_settings.hostname);
+  }
+
+  if (ppp_settings.user[0] == 0) {
+    strcpy(ppp_settings.user, ppp_settings.our_name);
+  }
+
+  /* If authentication is required, ask peer for CHAP or PAP. */
+  if (ppp_settings.auth_required && !wo->neg_chap && !wo->neg_upap) {
+    wo->neg_chap = 1;
+    wo->neg_upap = 1;
+  }
+  
+  /*
+   * Check whether we have appropriate secrets to use
+   * to authenticate the peer.
+   */
+  can_auth = wo->neg_upap && have_pap_secret();
+  if (!can_auth && wo->neg_chap) {
+    remote = ipwo->accept_remote? 0: ipwo->hisaddr;
+    can_auth = have_chap_secret(ppp_settings.remote_name, ppp_settings.our_name, remote);
+  }
+
+  if (ppp_settings.auth_required && !can_auth) {
+    ppp_panic("No auth secret");
+  }
+}
+#endif /* UNUSED */
+
+/*
+ * auth_reset - called when LCP is starting negotiations to recheck
+ * authentication options, i.e. whether we have appropriate secrets
+ * to use for authenticating ourselves and/or the peer.
+ */
+void
+auth_reset(int unit)
+{
+  lcp_options *go = &lcp_gotoptions[unit];
+  lcp_options *ao = &lcp_allowoptions[0];
+  ipcp_options *ipwo = &ipcp_wantoptions[0];
+  u32_t remote;
+
+  AUTHDEBUG(LOG_INFO, ("auth_reset: %d\n", unit));
+  ao->neg_upap = !ppp_settings.refuse_pap && (ppp_settings.passwd[0] != 0 || get_pap_passwd(unit, NULL, NULL));
+  ao->neg_chap = !ppp_settings.refuse_chap && ppp_settings.passwd[0] != 0 /*have_chap_secret(ppp_settings.user, ppp_settings.remote_name, (u32_t)0)*/;
+
+  if (go->neg_upap && !have_pap_secret()) {
+    go->neg_upap = 0;
+  }
+  if (go->neg_chap) {
+    remote = ipwo->accept_remote? 0: ipwo->hisaddr;
+    if (!have_chap_secret(ppp_settings.remote_name, ppp_settings.our_name, remote)) {
+      go->neg_chap = 0;
+    }
+  }
+}
+
+#if PAP_SUPPORT
+/*
+ * check_passwd - Check the user name and passwd against the PAP secrets
+ * file.  If requested, also check against the system password database,
+ * and login the user if OK.
+ *
+ * returns:
+ *  UPAP_AUTHNAK: Authentication failed.
+ *  UPAP_AUTHACK: Authentication succeeded.
+ * In either case, msg points to an appropriate message.
+ */
+u_char
+check_passwd( int unit, char *auser, int userlen, char *apasswd, int passwdlen, char **msg, int *msglen)
+{
+#if 1 /* XXX Assume all entries OK. */
+  LWIP_UNUSED_ARG(unit);
+  LWIP_UNUSED_ARG(auser);
+  LWIP_UNUSED_ARG(userlen);
+  LWIP_UNUSED_ARG(apasswd);
+  LWIP_UNUSED_ARG(passwdlen);
+  LWIP_UNUSED_ARG(msglen);
+  *msg = (char *) 0;
+  return UPAP_AUTHACK;     /* XXX Assume all entries OK. */
+#else
+  u_char ret = 0;
+  struct wordlist *addrs = NULL;
+  char passwd[256], user[256];
+  char secret[MAXWORDLEN];
+  static u_short attempts = 0;
+  
+  /*
+   * Make copies of apasswd and auser, then null-terminate them.
+   */
+  BCOPY(apasswd, passwd, passwdlen);
+  passwd[passwdlen] = '\0';
+  BCOPY(auser, user, userlen);
+  user[userlen] = '\0';
+  *msg = (char *) 0;
+
+  /* XXX Validate user name and password. */
+  ret = UPAP_AUTHACK;     /* XXX Assume all entries OK. */
+      
+  if (ret == UPAP_AUTHNAK) {
+    if (*msg == (char *) 0) {
+      *msg = "Login incorrect";
+    }
+    *msglen = strlen(*msg);
+    /*
+     * Frustrate passwd stealer programs.
+     * Allow 10 tries, but start backing off after 3 (stolen from login).
+     * On 10'th, drop the connection.
+     */
+    if (attempts++ >= 10) {
+      AUTHDEBUG(LOG_WARNING, ("%d LOGIN FAILURES BY %s\n", attempts, user));
+      /*ppp_panic("Excess Bad Logins");*/
+    }
+    if (attempts > 3) {
+      /* @todo: this was sleep(), i.e. seconds, not milliseconds
+       * I don't think we really need this in lwIP - we would block tcpip_thread!
+       */
+      /*sys_msleep((attempts - 3) * 5);*/
+    }
+    if (addrs != NULL) {
+      free_wordlist(addrs);
+    }
+  } else {
+    attempts = 0; /* Reset count */
+    if (*msg == (char *) 0) {
+      *msg = "Login ok";
+    }
+    *msglen = strlen(*msg);
+    set_allowed_addrs(unit, addrs);
+  }
+
+  BZERO(passwd, sizeof(passwd));
+  BZERO(secret, sizeof(secret));
+
+  return ret;
+#endif
+}
+#endif /* PAP_SUPPORT */
+
+#if 0 /* UNUSED */
+/*
+ * This function is needed for PAM.
+ */
+
+#ifdef USE_PAM
+
+/* lwip does not support PAM*/
+
+#endif  /* USE_PAM */
+
+#endif /* UNUSED */
+
+
+#if 0 /* UNUSED */
+/*
+ * plogin - Check the user name and password against the system
+ * password database, and login the user if OK.
+ *
+ * returns:
+ *  UPAP_AUTHNAK: Login failed.
+ *  UPAP_AUTHACK: Login succeeded.
+ * In either case, msg points to an appropriate message.
+ */
+static int
+plogin(char *user, char *passwd, char **msg, int *msglen)
+{
+
+  LWIP_UNUSED_ARG(user);
+  LWIP_UNUSED_ARG(passwd);
+  LWIP_UNUSED_ARG(msg);
+  LWIP_UNUSED_ARG(msglen);
+
+
+ /* The new lines are here align the file when 
+  * compared against the pppd 2.3.11 code */
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+  /* XXX Fail until we decide that we want to support logins. */
+  return (UPAP_AUTHNAK);
+}
+#endif
+
+
+
+/*
+ * plogout - Logout the user.
+ */
+static void
+plogout(void)
+{
+  logged_in = 0;
+}
+
+/*
+ * null_login - Check if a username of "" and a password of "" are
+ * acceptable, and iff so, set the list of acceptable IP addresses
+ * and return 1.
+ */
+static int
+null_login(int unit)
+{
+  LWIP_UNUSED_ARG(unit);
+  /* XXX Fail until we decide that we want to support logins. */
+  return 0;
+}
+
+
+/*
+ * get_pap_passwd - get a password for authenticating ourselves with
+ * our peer using PAP.  Returns 1 on success, 0 if no suitable password
+ * could be found.
+ */
+static int
+get_pap_passwd(int unit, char *user, char *passwd)
+{
+  LWIP_UNUSED_ARG(unit);
+/* normally we would reject PAP if no password is provided,
+   but this causes problems with some providers (like CHT in Taiwan)
+   who incorrectly request PAP and expect a bogus/empty password, so
+   always provide a default user/passwd of "none"/"none"
+
+   @todo: This should be configured by the user, instead of being hardcoded here!
+*/
+  if(user) {
+    strcpy(user, "none");
+  }
+  if(passwd) {
+    strcpy(passwd, "none");
+  }
+  return 1;
+}
+
+/*
+ * have_pap_secret - check whether we have a PAP file with any
+ * secrets that we could possibly use for authenticating the peer.
+ */
+static int
+have_pap_secret(void)
+{
+  /* XXX Fail until we set up our passwords. */
+  return 0;
+}
+
+/*
+ * have_chap_secret - check whether we have a CHAP file with a
+ * secret that we could possibly use for authenticating `client'
+ * on `server'.  Either can be the null string, meaning we don't
+ * know the identity yet.
+ */
+static int
+have_chap_secret(char *client, char *server, u32_t remote)
+{
+  LWIP_UNUSED_ARG(client);
+  LWIP_UNUSED_ARG(server);
+  LWIP_UNUSED_ARG(remote);
+
+  /* XXX Fail until we set up our passwords. */
+  return 0;
+}
+#if CHAP_SUPPORT
+
+/*
+ * get_secret - open the CHAP secret file and return the secret
+ * for authenticating the given client on the given server.
+ * (We could be either client or server).
+ */
+int
+get_secret(int unit, char *client, char *server, char *secret, int *secret_len, int save_addrs)
+{
+#if 1
+  int len;
+  struct wordlist *addrs;
+
+  LWIP_UNUSED_ARG(unit);
+  LWIP_UNUSED_ARG(server);
+  LWIP_UNUSED_ARG(save_addrs);
+
+  addrs = NULL;
+
+  if(!client || !client[0] || strcmp(client, ppp_settings.user)) {
+    return 0;
+  }
+
+  len = (int)strlen(ppp_settings.passwd);
+  if (len > MAXSECRETLEN) {
+    AUTHDEBUG(LOG_ERR, ("Secret for %s on %s is too long\n", client, server));
+    len = MAXSECRETLEN;
+  }
+
+  BCOPY(ppp_settings.passwd, secret, len);
+  *secret_len = len;
+
+  return 1;
+#else
+  int ret = 0, len;
+  struct wordlist *addrs;
+  char secbuf[MAXWORDLEN];
+  
+  addrs = NULL;
+  secbuf[0] = 0;
+
+  /* XXX Find secret. */
+  if (ret < 0) {
+    return 0;
+  }
+
+  if (save_addrs) {
+    set_allowed_addrs(unit, addrs);
+  }
+
+  len = strlen(secbuf);
+  if (len > MAXSECRETLEN) {
+    AUTHDEBUG(LOG_ERR, ("Secret for %s on %s is too long\n", client, server));
+    len = MAXSECRETLEN;
+  }
+
+  BCOPY(secbuf, secret, len);
+  BZERO(secbuf, sizeof(secbuf));
+  *secret_len = len;
+
+  return 1;
+#endif
+}
+#endif /* CHAP_SUPPORT */
+
+
+#if 0 /* PAP_SUPPORT || CHAP_SUPPORT */
+/*
+ * set_allowed_addrs() - set the list of allowed addresses.
+ */
+static void
+set_allowed_addrs(int unit, struct wordlist *addrs)
+{
+  if (addresses[unit] != NULL) {
+    free_wordlist(addresses[unit]);
+  }
+  addresses[unit] = addrs;
+
+#if 0
+  /*
+   * If there's only one authorized address we might as well
+   * ask our peer for that one right away
+   */
+  if (addrs != NULL && addrs->next == NULL) {
+    char *p = addrs->word;
+    struct ipcp_options *wo = &ipcp_wantoptions[unit];
+    u32_t a;
+    struct hostent *hp;
+    
+    if (wo->hisaddr == 0 && *p != '!' && *p != '-' && strchr(p, '/') == NULL) {
+      hp = gethostbyname(p);
+      if (hp != NULL && hp->h_addrtype == AF_INET) {
+        a = *(u32_t *)hp->h_addr;
+      } else {
+        a = inet_addr(p);
+      }
+      if (a != (u32_t) -1) {
+        wo->hisaddr = a;
+      }
+    }
+  }
+#endif
+}
+#endif /* 0 */ /* PAP_SUPPORT || CHAP_SUPPORT */
+
+/*
+ * auth_ip_addr - check whether the peer is authorized to use
+ * a given IP address.  Returns 1 if authorized, 0 otherwise.
+ */
+int
+auth_ip_addr(int unit, u32_t addr)
+{
+  return ip_addr_check(addr, addresses[unit]);
+}
+
+static int /* @todo: integrate this funtion into auth_ip_addr()*/
+ip_addr_check(u32_t addr, struct wordlist *addrs)
+{
+  /* don't allow loopback or multicast address */
+  if (bad_ip_adrs(addr)) {
+    return 0;
+  }
+
+  if (addrs == NULL) {
+    return !ppp_settings.auth_required; /* no addresses authorized */
+  }
+
+  /* XXX All other addresses allowed. */
+  return 1;
+}
+
+/*
+ * bad_ip_adrs - return 1 if the IP address is one we don't want
+ * to use, such as an address in the loopback net or a multicast address.
+ * addr is in network byte order.
+ */
+int
+bad_ip_adrs(u32_t addr)
+{
+  addr = ntohl(addr);
+  return (addr >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET
+      || IN_MULTICAST(addr) || IN_BADCLASS(addr);
+}
+
+#if 0 /* UNUSED */ /* PAP_SUPPORT || CHAP_SUPPORT */
+/*
+ * some_ip_ok - check a wordlist to see if it authorizes any
+ * IP address(es).
+ */
+static int
+some_ip_ok(struct wordlist *addrs)
+{
+    for (; addrs != 0; addrs = addrs->next) {
+      if (addrs->word[0] == '-')
+        break;
+      if (addrs->word[0] != '!')
+        return 1; /* some IP address is allowed */
+    }
+    return 0;
+}
+
+/*
+ * check_access - complain if a secret file has too-liberal permissions.
+ */
+static void
+check_access(FILE *f, char *filename)
+{
+    struct stat sbuf;
+
+    if (fstat(fileno(f), &sbuf) < 0) {
+      warn("cannot stat secret file %s: %m", filename);
+    } else if ((sbuf.st_mode & (S_IRWXG | S_IRWXO)) != 0) {
+      warn("Warning - secret file %s has world and/or group access",
+            filename);
+    }
+}
+
+
+/*
+ * scan_authfile - Scan an authorization file for a secret suitable
+ * for authenticating `client' on `server'.  The return value is -1
+ * if no secret is found, otherwise >= 0.  The return value has
+ * NONWILD_CLIENT set if the secret didn't have "*" for the client, and
+ * NONWILD_SERVER set if the secret didn't have "*" for the server.
+ * Any following words on the line up to a "--" (i.e. address authorization
+ * info) are placed in a wordlist and returned in *addrs.  Any
+ * following words (extra options) are placed in a wordlist and
+ * returned in *opts.
+ * We assume secret is NULL or points to MAXWORDLEN bytes of space.
+ */
+static int
+scan_authfile(FILE *f, char *client, char *server, char *secret, struct wordlist **addrs, struct wordlist **opts, char *filename)
+{
+  /* We do not (currently) need this in lwip  */
+  return 0; /* dummy */
+}
+/*
+ * free_wordlist - release memory allocated for a wordlist.
+ */
+static void
+free_wordlist(struct wordlist *wp)
+{
+  struct wordlist *next;
+
+  while (wp != NULL) {
+    next = wp->next;
+    free(wp);
+    wp = next;
+  }
+}
+
+/*
+ * auth_script_done - called when the auth-up or auth-down script
+ * has finished.
+ */
+static void
+auth_script_done(void *arg)
+{
+    auth_script_pid = 0;
+    switch (auth_script_state) {
+    case s_up:
+      if (auth_state == s_down) {
+        auth_script_state = s_down;
+        auth_script(_PATH_AUTHDOWN);
+      }
+      break;
+    case s_down:
+      if (auth_state == s_up) {
+        auth_script_state = s_up;
+        auth_script(_PATH_AUTHUP);
+      }
+      break;
+    }
+}
+
+/*
+ * auth_script - execute a script with arguments
+ * interface-name peer-name real-user tty speed
+ */
+static void
+auth_script(char *script)
+{
+    char strspeed[32];
+    struct passwd *pw;
+    char struid[32];
+    char *user_name;
+    char *argv[8];
+
+    if ((pw = getpwuid(getuid())) != NULL && pw->pw_name != NULL)
+      user_name = pw->pw_name;
+    else {
+      slprintf(struid, sizeof(struid), "%d", getuid());
+      user_name = struid;
+    }
+    slprintf(strspeed, sizeof(strspeed), "%d", baud_rate);
+
+    argv[0] = script;
+    argv[1] = ifname;
+    argv[2] = peer_authname;
+    argv[3] = user_name;
+    argv[4] = devnam;
+    argv[5] = strspeed;
+    argv[6] = NULL;
+
+    auth_script_pid = run_program(script, argv, 0, auth_script_done, NULL);
+}
+#endif  /* 0 */ /* PAP_SUPPORT || CHAP_SUPPORT */
+#endif /* PPP_SUPPORT */
diff --git a/core/lwip/src/netif/ppp/auth.h b/core/lwip/src/netif/ppp/auth.h
new file mode 100644
index 00000000..a8069ec4
--- /dev/null
+++ b/core/lwip/src/netif/ppp/auth.h
@@ -0,0 +1,111 @@
+/*****************************************************************************
+* auth.h -  PPP Authentication and phase control header file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* portions Copyright (c) 1998 Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 97-12-04 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
+*   Original derived from BSD pppd.h.
+*****************************************************************************/
+/*
+ * pppd.h - PPP daemon global declarations.
+ *
+ * Copyright (c) 1989 Carnegie Mellon University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Carnegie Mellon University.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+#ifndef AUTH_H
+#define AUTH_H
+
+/***********************
+*** PUBLIC FUNCTIONS ***
+***********************/
+
+/* we are starting to use the link */
+void link_required (int);
+
+/* we are finished with the link */
+void link_terminated (int);
+
+/* the LCP layer has left the Opened state */
+void link_down (int);
+
+/* the link is up; authenticate now */
+void link_established (int);
+
+/* a network protocol has come up */
+void np_up (int, u16_t);
+
+/* a network protocol has gone down */
+void np_down (int, u16_t);
+
+/* a network protocol no longer needs link */
+void np_finished (int, u16_t);
+
+/* peer failed to authenticate itself */
+void auth_peer_fail (int, u16_t);
+
+/* peer successfully authenticated itself */
+void auth_peer_success (int, u16_t, char *, int);
+
+/* we failed to authenticate ourselves */
+void auth_withpeer_fail (int, u16_t);
+
+/* we successfully authenticated ourselves */
+void auth_withpeer_success (int, u16_t);
+
+/* check authentication options supplied */
+void auth_check_options (void);
+
+/* check what secrets we have */
+void auth_reset (int);
+
+/* Check peer-supplied username/password */
+u_char check_passwd (int, char *, int, char *, int, char **, int *);
+
+/* get "secret" for chap */
+int  get_secret (int, char *, char *, char *, int *, int);
+
+/* check if IP address is authorized */
+int  auth_ip_addr (int, u32_t);
+
+/* check if IP address is unreasonable */
+int  bad_ip_adrs (u32_t);
+
+#endif /* AUTH_H */
diff --git a/core/lwip/src/netif/ppp/chap.c b/core/lwip/src/netif/ppp/chap.c
new file mode 100644
index 00000000..3a49ff8a
--- /dev/null
+++ b/core/lwip/src/netif/ppp/chap.c
@@ -0,0 +1,908 @@
+/*** WARNING - THIS HAS NEVER BEEN FINISHED ***/
+/*****************************************************************************
+* chap.c - Network Challenge Handshake Authentication Protocol program file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* portions Copyright (c) 1997 by Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 97-12-04 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
+*   Original based on BSD chap.c.
+*****************************************************************************/
+/*
+ * chap.c - Challenge Handshake Authentication Protocol.
+ *
+ * Copyright (c) 1993 The Australian National University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by the Australian National University.  The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * Copyright (c) 1991 Gregory M. Christy.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Gregory M. Christy.  The name of the author may not be used to
+ * endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#include "lwip/opt.h"
+
+#if PPP_SUPPORT  /* don't build if not configured for use in lwipopts.h */
+
+#if CHAP_SUPPORT /* don't build if not configured for use in lwipopts.h */
+
+#include "ppp.h"
+#include "pppdebug.h"
+
+#include "magic.h"
+#include "randm.h"
+#include "auth.h"
+#include "md5.h"
+#include "chap.h"
+#include "chpms.h"
+
+#include <string.h>
+
+#if 0 /* UNUSED */
+/*
+ * Command-line options.
+ */
+static option_t chap_option_list[] = {
+    { "chap-restart", o_int, &chap[0].timeouttime,
+      "Set timeout for CHAP" },
+    { "chap-max-challenge", o_int, &chap[0].max_transmits,
+      "Set max #xmits for challenge" },
+    { "chap-interval", o_int, &chap[0].chal_interval,
+      "Set interval for rechallenge" },
+#ifdef MSLANMAN
+    { "ms-lanman", o_bool, &ms_lanman,
+      "Use LanMan passwd when using MS-CHAP", 1 },
+#endif
+    { NULL }
+};
+#endif /* UNUSED */
+
+/*
+ * Protocol entry points.
+ */
+static void ChapInit (int);
+static void ChapLowerUp (int);
+static void ChapLowerDown (int);
+static void ChapInput (int, u_char *, int);
+static void ChapProtocolReject (int);
+#if PPP_ADDITIONAL_CALLBACKS
+static int  ChapPrintPkt (u_char *, int, void (*) (void *, char *, ...), void *);
+#endif
+
+struct protent chap_protent = {
+  PPP_CHAP,
+  ChapInit,
+  ChapInput,
+  ChapProtocolReject,
+  ChapLowerUp,
+  ChapLowerDown,
+  NULL,
+  NULL,
+#if PPP_ADDITIONAL_CALLBACKS
+  ChapPrintPkt,
+  NULL,
+#endif /* PPP_ADDITIONAL_CALLBACKS */
+  1,
+  "CHAP",
+#if PPP_ADDITIONAL_CALLBACKS
+  NULL,
+  NULL,
+  NULL
+#endif /* PPP_ADDITIONAL_CALLBACKS */
+};
+
+chap_state chap[NUM_PPP]; /* CHAP state; one for each unit */
+
+static void ChapChallengeTimeout (void *);
+static void ChapResponseTimeout (void *);
+static void ChapReceiveChallenge (chap_state *, u_char *, u_char, int);
+static void ChapRechallenge (void *);
+static void ChapReceiveResponse (chap_state *, u_char *, int, int);
+static void ChapReceiveSuccess(chap_state *cstate, u_char *inp, u_char id, int len);
+static void ChapReceiveFailure(chap_state *cstate, u_char *inp, u_char id, int len);
+static void ChapSendStatus (chap_state *, int);
+static void ChapSendChallenge (chap_state *);
+static void ChapSendResponse (chap_state *);
+static void ChapGenChallenge (chap_state *);
+
+/*
+ * ChapInit - Initialize a CHAP unit.
+ */
+static void
+ChapInit(int unit)
+{
+  chap_state *cstate = &chap[unit];
+
+  BZERO(cstate, sizeof(*cstate));
+  cstate->unit = unit;
+  cstate->clientstate = CHAPCS_INITIAL;
+  cstate->serverstate = CHAPSS_INITIAL;
+  cstate->timeouttime = CHAP_DEFTIMEOUT;
+  cstate->max_transmits = CHAP_DEFTRANSMITS;
+  /* random number generator is initialized in magic_init */
+}
+
+
+/*
+ * ChapAuthWithPeer - Authenticate us with our peer (start client).
+ *
+ */
+void
+ChapAuthWithPeer(int unit, char *our_name, u_char digest)
+{
+  chap_state *cstate = &chap[unit];
+
+  cstate->resp_name = our_name;
+  cstate->resp_type = digest;
+
+  if (cstate->clientstate == CHAPCS_INITIAL ||
+      cstate->clientstate == CHAPCS_PENDING) {
+    /* lower layer isn't up - wait until later */
+    cstate->clientstate = CHAPCS_PENDING;
+    return;
+  }
+
+  /*
+   * We get here as a result of LCP coming up.
+   * So even if CHAP was open before, we will 
+   * have to re-authenticate ourselves.
+   */
+  cstate->clientstate = CHAPCS_LISTEN;
+}
+
+
+/*
+ * ChapAuthPeer - Authenticate our peer (start server).
+ */
+void
+ChapAuthPeer(int unit, char *our_name, u_char digest)
+{
+  chap_state *cstate = &chap[unit];
+
+  cstate->chal_name = our_name;
+  cstate->chal_type = digest;
+  
+  if (cstate->serverstate == CHAPSS_INITIAL ||
+      cstate->serverstate == CHAPSS_PENDING) {
+    /* lower layer isn't up - wait until later */
+    cstate->serverstate = CHAPSS_PENDING;
+    return;
+  }
+
+  ChapGenChallenge(cstate);
+  ChapSendChallenge(cstate);    /* crank it up dude! */
+  cstate->serverstate = CHAPSS_INITIAL_CHAL;
+}
+
+
+/*
+ * ChapChallengeTimeout - Timeout expired on sending challenge.
+ */
+static void
+ChapChallengeTimeout(void *arg)
+{
+  chap_state *cstate = (chap_state *) arg;
+
+  /* if we aren't sending challenges, don't worry.  then again we */
+  /* probably shouldn't be here either */
+  if (cstate->serverstate != CHAPSS_INITIAL_CHAL &&
+      cstate->serverstate != CHAPSS_RECHALLENGE) {
+    return;
+  }
+
+  if (cstate->chal_transmits >= cstate->max_transmits) {
+    /* give up on peer */
+    CHAPDEBUG(LOG_ERR, ("Peer failed to respond to CHAP challenge\n"));
+    cstate->serverstate = CHAPSS_BADAUTH;
+    auth_peer_fail(cstate->unit, PPP_CHAP);
+    return;
+  }
+
+  ChapSendChallenge(cstate); /* Re-send challenge */
+}
+
+
+/*
+ * ChapResponseTimeout - Timeout expired on sending response.
+ */
+static void
+ChapResponseTimeout(void *arg)
+{
+  chap_state *cstate = (chap_state *) arg;
+
+  /* if we aren't sending a response, don't worry. */
+  if (cstate->clientstate != CHAPCS_RESPONSE) {
+    return;
+  }
+
+  ChapSendResponse(cstate);    /* re-send response */
+}
+
+
+/*
+ * ChapRechallenge - Time to challenge the peer again.
+ */
+static void
+ChapRechallenge(void *arg)
+{
+  chap_state *cstate = (chap_state *) arg;
+  
+  /* if we aren't sending a response, don't worry. */
+  if (cstate->serverstate != CHAPSS_OPEN) {
+    return;
+  }
+
+  ChapGenChallenge(cstate);
+  ChapSendChallenge(cstate);
+  cstate->serverstate = CHAPSS_RECHALLENGE;
+}
+
+
+/*
+ * ChapLowerUp - The lower layer is up.
+ *
+ * Start up if we have pending requests.
+ */
+static void
+ChapLowerUp(int unit)
+{
+  chap_state *cstate = &chap[unit];
+
+  if (cstate->clientstate == CHAPCS_INITIAL) {
+    cstate->clientstate = CHAPCS_CLOSED;
+  } else if (cstate->clientstate == CHAPCS_PENDING) {
+    cstate->clientstate = CHAPCS_LISTEN;
+  }
+
+  if (cstate->serverstate == CHAPSS_INITIAL) {
+    cstate->serverstate = CHAPSS_CLOSED;
+  } else if (cstate->serverstate == CHAPSS_PENDING) {
+    ChapGenChallenge(cstate);
+    ChapSendChallenge(cstate);
+    cstate->serverstate = CHAPSS_INITIAL_CHAL;
+  }
+}
+
+
+/*
+ * ChapLowerDown - The lower layer is down.
+ *
+ * Cancel all timeouts.
+ */
+static void
+ChapLowerDown(int unit)
+{
+  chap_state *cstate = &chap[unit];
+
+  /* Timeout(s) pending?  Cancel if so. */
+  if (cstate->serverstate == CHAPSS_INITIAL_CHAL ||
+      cstate->serverstate == CHAPSS_RECHALLENGE) {
+    UNTIMEOUT(ChapChallengeTimeout, cstate);
+  } else if (cstate->serverstate == CHAPSS_OPEN
+      && cstate->chal_interval != 0) {
+    UNTIMEOUT(ChapRechallenge, cstate);
+  }
+  if (cstate->clientstate == CHAPCS_RESPONSE) {
+    UNTIMEOUT(ChapResponseTimeout, cstate);
+  }
+  cstate->clientstate = CHAPCS_INITIAL;
+  cstate->serverstate = CHAPSS_INITIAL;
+}
+
+
+/*
+ * ChapProtocolReject - Peer doesn't grok CHAP.
+ */
+static void
+ChapProtocolReject(int unit)
+{
+  chap_state *cstate = &chap[unit];
+  
+  if (cstate->serverstate != CHAPSS_INITIAL &&
+      cstate->serverstate != CHAPSS_CLOSED) {
+    auth_peer_fail(unit, PPP_CHAP);
+  }
+  if (cstate->clientstate != CHAPCS_INITIAL &&
+      cstate->clientstate != CHAPCS_CLOSED) {
+    auth_withpeer_fail(unit, PPP_CHAP); /* lwip: just sets the PPP error code on this unit to PPPERR_AUTHFAIL */
+  }
+  ChapLowerDown(unit); /* shutdown chap */
+}
+
+
+/*
+ * ChapInput - Input CHAP packet.
+ */
+static void
+ChapInput(int unit, u_char *inpacket, int packet_len)
+{
+  chap_state *cstate = &chap[unit];
+  u_char *inp;
+  u_char code, id;
+  int len;
+  
+  /*
+   * Parse header (code, id and length).
+   * If packet too short, drop it.
+   */
+  inp = inpacket;
+  if (packet_len < CHAP_HEADERLEN) {
+    CHAPDEBUG(LOG_INFO, ("ChapInput: rcvd short header.\n"));
+    return;
+  }
+  GETCHAR(code, inp);
+  GETCHAR(id, inp);
+  GETSHORT(len, inp);
+  if (len < CHAP_HEADERLEN) {
+    CHAPDEBUG(LOG_INFO, ("ChapInput: rcvd illegal length.\n"));
+    return;
+  }
+  if (len > packet_len) {
+    CHAPDEBUG(LOG_INFO, ("ChapInput: rcvd short packet.\n"));
+    return;
+  }
+  len -= CHAP_HEADERLEN;
+  
+  /*
+   * Action depends on code (as in fact it usually does :-).
+   */
+  switch (code) {
+    case CHAP_CHALLENGE:
+      ChapReceiveChallenge(cstate, inp, id, len);
+      break;
+    
+    case CHAP_RESPONSE:
+      ChapReceiveResponse(cstate, inp, id, len);
+      break;
+    
+    case CHAP_FAILURE:
+      ChapReceiveFailure(cstate, inp, id, len);
+      break;
+    
+    case CHAP_SUCCESS:
+      ChapReceiveSuccess(cstate, inp, id, len);
+      break;
+    
+    default:        /* Need code reject? */
+      CHAPDEBUG(LOG_WARNING, ("Unknown CHAP code (%d) received.\n", code));
+      break;
+  }
+}
+
+
+/*
+ * ChapReceiveChallenge - Receive Challenge and send Response.
+ */
+static void
+ChapReceiveChallenge(chap_state *cstate, u_char *inp, u_char id, int len)
+{
+  int rchallenge_len;
+  u_char *rchallenge;
+  int secret_len;
+  char secret[MAXSECRETLEN];
+  char rhostname[256];
+  MD5_CTX mdContext;
+  u_char hash[MD5_SIGNATURE_SIZE];
+
+  CHAPDEBUG(LOG_INFO, ("ChapReceiveChallenge: Rcvd id %d.\n", id));
+  if (cstate->clientstate == CHAPCS_CLOSED ||
+    cstate->clientstate == CHAPCS_PENDING) {
+    CHAPDEBUG(LOG_INFO, ("ChapReceiveChallenge: in state %d\n",
+         cstate->clientstate));
+    return;
+  }
+
+  if (len < 2) {
+    CHAPDEBUG(LOG_INFO, ("ChapReceiveChallenge: rcvd short packet.\n"));
+    return;
+  }
+
+  GETCHAR(rchallenge_len, inp);
+  len -= sizeof (u_char) + rchallenge_len;  /* now name field length */
+  if (len < 0) {
+    CHAPDEBUG(LOG_INFO, ("ChapReceiveChallenge: rcvd short packet.\n"));
+    return;
+  }
+  rchallenge = inp;
+  INCPTR(rchallenge_len, inp);
+
+  if (len >= (int)sizeof(rhostname)) {
+    len = sizeof(rhostname) - 1;
+  }
+  BCOPY(inp, rhostname, len);
+  rhostname[len] = '\000';
+
+  CHAPDEBUG(LOG_INFO, ("ChapReceiveChallenge: received name field '%s'\n",
+             rhostname));
+
+  /* Microsoft doesn't send their name back in the PPP packet */
+  if (ppp_settings.remote_name[0] != 0 && (ppp_settings.explicit_remote || rhostname[0] == 0)) {
+    strncpy(rhostname, ppp_settings.remote_name, sizeof(rhostname));
+    rhostname[sizeof(rhostname) - 1] = 0;
+    CHAPDEBUG(LOG_INFO, ("ChapReceiveChallenge: using '%s' as remote name\n",
+               rhostname));
+  }
+
+  /* get secret for authenticating ourselves with the specified host */
+  if (!get_secret(cstate->unit, cstate->resp_name, rhostname,
+                  secret, &secret_len, 0)) {
+    secret_len = 0;    /* assume null secret if can't find one */
+    CHAPDEBUG(LOG_WARNING, ("No CHAP secret found for authenticating us to %s\n",
+               rhostname));
+  }
+
+  /* cancel response send timeout if necessary */
+  if (cstate->clientstate == CHAPCS_RESPONSE) {
+    UNTIMEOUT(ChapResponseTimeout, cstate);
+  }
+
+  cstate->resp_id = id;
+  cstate->resp_transmits = 0;
+
+  /*  generate MD based on negotiated type */
+  switch (cstate->resp_type) { 
+
+  case CHAP_DIGEST_MD5:
+    MD5Init(&mdContext);
+    MD5Update(&mdContext, &cstate->resp_id, 1);
+    MD5Update(&mdContext, (u_char*)secret, secret_len);
+    MD5Update(&mdContext, rchallenge, rchallenge_len);
+    MD5Final(hash, &mdContext);
+    BCOPY(hash, cstate->response, MD5_SIGNATURE_SIZE);
+    cstate->resp_length = MD5_SIGNATURE_SIZE;
+    break;
+  
+#if MSCHAP_SUPPORT
+  case CHAP_MICROSOFT:
+    ChapMS(cstate, rchallenge, rchallenge_len, secret, secret_len);
+    break;
+#endif
+
+  default:
+    CHAPDEBUG(LOG_INFO, ("unknown digest type %d\n", cstate->resp_type));
+    return;
+  }
+
+  BZERO(secret, sizeof(secret));
+  ChapSendResponse(cstate);
+}
+
+
+/*
+ * ChapReceiveResponse - Receive and process response.
+ */
+static void
+ChapReceiveResponse(chap_state *cstate, u_char *inp, int id, int len)
+{
+  u_char *remmd, remmd_len;
+  int secret_len, old_state;
+  int code;
+  char rhostname[256];
+  MD5_CTX mdContext;
+  char secret[MAXSECRETLEN];
+  u_char hash[MD5_SIGNATURE_SIZE];
+
+  CHAPDEBUG(LOG_INFO, ("ChapReceiveResponse: Rcvd id %d.\n", id));
+  
+  if (cstate->serverstate == CHAPSS_CLOSED ||
+      cstate->serverstate == CHAPSS_PENDING) {
+    CHAPDEBUG(LOG_INFO, ("ChapReceiveResponse: in state %d\n",
+    cstate->serverstate));
+    return;
+  }
+
+  if (id != cstate->chal_id) {
+    return;      /* doesn't match ID of last challenge */
+  }
+
+  /*
+  * If we have received a duplicate or bogus Response,
+  * we have to send the same answer (Success/Failure)
+  * as we did for the first Response we saw.
+  */
+  if (cstate->serverstate == CHAPSS_OPEN) {
+    ChapSendStatus(cstate, CHAP_SUCCESS);
+    return;
+  }
+  if (cstate->serverstate == CHAPSS_BADAUTH) {
+    ChapSendStatus(cstate, CHAP_FAILURE);
+    return;
+  }
+  
+  if (len < 2) {
+    CHAPDEBUG(LOG_INFO, ("ChapReceiveResponse: rcvd short packet.\n"));
+    return;
+  }
+  GETCHAR(remmd_len, inp); /* get length of MD */
+  remmd = inp;             /* get pointer to MD */
+  INCPTR(remmd_len, inp);
+  
+  len -= sizeof (u_char) + remmd_len;
+  if (len < 0) {
+    CHAPDEBUG(LOG_INFO, ("ChapReceiveResponse: rcvd short packet.\n"));
+    return;
+  }
+
+  UNTIMEOUT(ChapChallengeTimeout, cstate);
+  
+  if (len >= (int)sizeof(rhostname)) {
+    len = sizeof(rhostname) - 1;
+  }
+  BCOPY(inp, rhostname, len);
+  rhostname[len] = '\000';
+
+  CHAPDEBUG(LOG_INFO, ("ChapReceiveResponse: received name field: %s\n",
+             rhostname));
+
+  /*
+  * Get secret for authenticating them with us,
+  * do the hash ourselves, and compare the result.
+  */
+  code = CHAP_FAILURE;
+  if (!get_secret(cstate->unit, rhostname, cstate->chal_name,
+                  secret, &secret_len, 1)) {
+    CHAPDEBUG(LOG_WARNING, ("No CHAP secret found for authenticating %s\n",
+               rhostname));
+  } else {
+    /*  generate MD based on negotiated type */
+    switch (cstate->chal_type) {
+
+      case CHAP_DIGEST_MD5:    /* only MD5 is defined for now */
+        if (remmd_len != MD5_SIGNATURE_SIZE) {
+          break;      /* it's not even the right length */
+        }
+        MD5Init(&mdContext);
+        MD5Update(&mdContext, &cstate->chal_id, 1);
+        MD5Update(&mdContext, (u_char*)secret, secret_len);
+        MD5Update(&mdContext, cstate->challenge, cstate->chal_len);
+        MD5Final(hash, &mdContext); 
+        
+        /* compare local and remote MDs and send the appropriate status */
+        if (memcmp (hash, remmd, MD5_SIGNATURE_SIZE) == 0) {
+          code = CHAP_SUCCESS;  /* they are the same! */
+        }
+        break;
+      
+      default:
+        CHAPDEBUG(LOG_INFO, ("unknown digest type %d\n", cstate->chal_type));
+    }
+  }
+  
+  BZERO(secret, sizeof(secret));
+  ChapSendStatus(cstate, code);
+
+  if (code == CHAP_SUCCESS) {
+    old_state = cstate->serverstate;
+    cstate->serverstate = CHAPSS_OPEN;
+    if (old_state == CHAPSS_INITIAL_CHAL) {
+      auth_peer_success(cstate->unit, PPP_CHAP, rhostname, len);
+    }
+    if (cstate->chal_interval != 0) {
+      TIMEOUT(ChapRechallenge, cstate, cstate->chal_interval);
+    }
+  } else {
+    CHAPDEBUG(LOG_ERR, ("CHAP peer authentication failed\n"));
+    cstate->serverstate = CHAPSS_BADAUTH;
+    auth_peer_fail(cstate->unit, PPP_CHAP);
+  }
+}
+
+/*
+ * ChapReceiveSuccess - Receive Success
+ */
+static void
+ChapReceiveSuccess(chap_state *cstate, u_char *inp, u_char id, int len)
+{
+  LWIP_UNUSED_ARG(id);
+  LWIP_UNUSED_ARG(inp);
+
+  CHAPDEBUG(LOG_INFO, ("ChapReceiveSuccess: Rcvd id %d.\n", id));
+
+  if (cstate->clientstate == CHAPCS_OPEN) {
+    /* presumably an answer to a duplicate response */
+    return;
+  }
+
+  if (cstate->clientstate != CHAPCS_RESPONSE) {
+    /* don't know what this is */
+    CHAPDEBUG(LOG_INFO, ("ChapReceiveSuccess: in state %d\n",
+               cstate->clientstate));
+    return;
+  }
+  
+  UNTIMEOUT(ChapResponseTimeout, cstate);
+  
+  /*
+   * Print message.
+   */
+  if (len > 0) {
+    PRINTMSG(inp, len);
+  }
+
+  cstate->clientstate = CHAPCS_OPEN;
+
+  auth_withpeer_success(cstate->unit, PPP_CHAP);
+}
+
+
+/*
+ * ChapReceiveFailure - Receive failure.
+ */
+static void
+ChapReceiveFailure(chap_state *cstate, u_char *inp, u_char id, int len)
+{
+  LWIP_UNUSED_ARG(id);
+  LWIP_UNUSED_ARG(inp);
+
+  CHAPDEBUG(LOG_INFO, ("ChapReceiveFailure: Rcvd id %d.\n", id));
+
+  if (cstate->clientstate != CHAPCS_RESPONSE) {
+    /* don't know what this is */
+    CHAPDEBUG(LOG_INFO, ("ChapReceiveFailure: in state %d\n",
+               cstate->clientstate));
+    return;
+  }
+
+  UNTIMEOUT(ChapResponseTimeout, cstate);
+
+  /*
+   * Print message.
+   */
+  if (len > 0) {
+    PRINTMSG(inp, len);
+  }
+
+  CHAPDEBUG(LOG_ERR, ("CHAP authentication failed\n"));
+  auth_withpeer_fail(cstate->unit, PPP_CHAP); /* lwip: just sets the PPP error code on this unit to PPPERR_AUTHFAIL */
+}
+
+
+/*
+ * ChapSendChallenge - Send an Authenticate challenge.
+ */
+static void
+ChapSendChallenge(chap_state *cstate)
+{
+  u_char *outp;
+  int chal_len, name_len;
+  int outlen;
+  
+  chal_len = cstate->chal_len;
+  name_len = (int)strlen(cstate->chal_name);
+  outlen = CHAP_HEADERLEN + sizeof (u_char) + chal_len + name_len;
+  outp = outpacket_buf[cstate->unit];
+
+  MAKEHEADER(outp, PPP_CHAP);    /* paste in a CHAP header */
+
+  PUTCHAR(CHAP_CHALLENGE, outp);
+  PUTCHAR(cstate->chal_id, outp);
+  PUTSHORT(outlen, outp);
+
+  PUTCHAR(chal_len, outp);    /* put length of challenge */
+  BCOPY(cstate->challenge, outp, chal_len);
+  INCPTR(chal_len, outp);
+
+  BCOPY(cstate->chal_name, outp, name_len);  /* append hostname */
+  
+  pppWrite(cstate->unit, outpacket_buf[cstate->unit], outlen + PPP_HDRLEN);
+
+  CHAPDEBUG(LOG_INFO, ("ChapSendChallenge: Sent id %d.\n", cstate->chal_id));
+  
+  TIMEOUT(ChapChallengeTimeout, cstate, cstate->timeouttime);
+  ++cstate->chal_transmits;
+}
+
+
+/*
+ * ChapSendStatus - Send a status response (ack or nak).
+ */
+static void
+ChapSendStatus(chap_state *cstate, int code)
+{
+  u_char *outp;
+  int outlen, msglen;
+  char msg[256]; /* @todo: this can be a char*, no strcpy needed */
+
+  if (code == CHAP_SUCCESS) {
+    strcpy(msg, "Welcome!");
+  } else {
+    strcpy(msg, "I don't like you.  Go 'way.");
+  }
+  msglen = (int)strlen(msg);
+
+  outlen = CHAP_HEADERLEN + msglen;
+  outp = outpacket_buf[cstate->unit];
+
+  MAKEHEADER(outp, PPP_CHAP);    /* paste in a header */
+  
+  PUTCHAR(code, outp);
+  PUTCHAR(cstate->chal_id, outp);
+  PUTSHORT(outlen, outp);
+  BCOPY(msg, outp, msglen);
+  pppWrite(cstate->unit, outpacket_buf[cstate->unit], outlen + PPP_HDRLEN);
+
+  CHAPDEBUG(LOG_INFO, ("ChapSendStatus: Sent code %d, id %d.\n", code,
+             cstate->chal_id));
+}
+
+/*
+ * ChapGenChallenge is used to generate a pseudo-random challenge string of
+ * a pseudo-random length between min_len and max_len.  The challenge
+ * string and its length are stored in *cstate, and various other fields of
+ * *cstate are initialized.
+ */
+
+static void
+ChapGenChallenge(chap_state *cstate)
+{
+  int chal_len;
+  u_char *ptr = cstate->challenge;
+  int i;
+
+  /* pick a random challenge length between MIN_CHALLENGE_LENGTH and 
+     MAX_CHALLENGE_LENGTH */  
+  chal_len = (unsigned)
+        ((((magic() >> 16) *
+              (MAX_CHALLENGE_LENGTH - MIN_CHALLENGE_LENGTH)) >> 16)
+           + MIN_CHALLENGE_LENGTH);
+  LWIP_ASSERT("chal_len <= 0xff", chal_len <= 0xffff);
+  cstate->chal_len = (u_char)chal_len;
+  cstate->chal_id = ++cstate->id;
+  cstate->chal_transmits = 0;
+
+  /* generate a random string */
+  for (i = 0; i < chal_len; i++ ) {
+    *ptr++ = (char) (magic() & 0xff);
+  }
+}
+
+/*
+ * ChapSendResponse - send a response packet with values as specified
+ * in *cstate.
+ */
+/* ARGSUSED */
+static void
+ChapSendResponse(chap_state *cstate)
+{
+  u_char *outp;
+  int outlen, md_len, name_len;
+
+  md_len = cstate->resp_length;
+  name_len = (int)strlen(cstate->resp_name);
+  outlen = CHAP_HEADERLEN + sizeof (u_char) + md_len + name_len;
+  outp = outpacket_buf[cstate->unit];
+
+  MAKEHEADER(outp, PPP_CHAP);
+  
+  PUTCHAR(CHAP_RESPONSE, outp);  /* we are a response */
+  PUTCHAR(cstate->resp_id, outp);  /* copy id from challenge packet */
+  PUTSHORT(outlen, outp);      /* packet length */
+  
+  PUTCHAR(md_len, outp);      /* length of MD */
+  BCOPY(cstate->response, outp, md_len);    /* copy MD to buffer */
+  INCPTR(md_len, outp);
+
+  BCOPY(cstate->resp_name, outp, name_len);  /* append our name */
+
+  /* send the packet */
+  pppWrite(cstate->unit, outpacket_buf[cstate->unit], outlen + PPP_HDRLEN);
+
+  cstate->clientstate = CHAPCS_RESPONSE;
+  TIMEOUT(ChapResponseTimeout, cstate, cstate->timeouttime);
+  ++cstate->resp_transmits;
+}
+
+#if PPP_ADDITIONAL_CALLBACKS
+static char *ChapCodenames[] = {
+  "Challenge", "Response", "Success", "Failure"
+};
+/*
+ * ChapPrintPkt - print the contents of a CHAP packet.
+ */
+static int
+ChapPrintPkt( u_char *p, int plen, void (*printer) (void *, char *, ...), void *arg)
+{
+  int code, id, len;
+  int clen, nlen;
+  u_char x;
+
+  if (plen < CHAP_HEADERLEN) {
+    return 0;
+  }
+  GETCHAR(code, p);
+  GETCHAR(id, p);
+  GETSHORT(len, p);
+  if (len < CHAP_HEADERLEN || len > plen) {
+    return 0;
+  }
+
+  if (code >= 1 && code <= sizeof(ChapCodenames) / sizeof(char *)) {
+    printer(arg, " %s", ChapCodenames[code-1]);
+  } else {
+    printer(arg, " code=0x%x", code);
+  }
+  printer(arg, " id=0x%x", id);
+  len -= CHAP_HEADERLEN;
+  switch (code) {
+    case CHAP_CHALLENGE:
+    case CHAP_RESPONSE:
+      if (len < 1) {
+        break;
+      }
+      clen = p[0];
+      if (len < clen + 1) {
+        break;
+      }
+      ++p;
+      nlen = len - clen - 1;
+      printer(arg, " <");
+      for (; clen > 0; --clen) {
+        GETCHAR(x, p);
+        printer(arg, "%.2x", x);
+      }
+      printer(arg, ">, name = %.*Z", nlen, p);
+      break;
+    case CHAP_FAILURE:
+    case CHAP_SUCCESS:
+      printer(arg, " %.*Z", len, p);
+      break;
+    default:
+      for (clen = len; clen > 0; --clen) {
+        GETCHAR(x, p);
+        printer(arg, " %.2x", x);
+      }
+  }
+
+  return len + CHAP_HEADERLEN;
+}
+#endif /* PPP_ADDITIONAL_CALLBACKS */
+
+#endif /* CHAP_SUPPORT */
+
+#endif /* PPP_SUPPORT */
diff --git a/core/lwip/src/netif/ppp/chap.h b/core/lwip/src/netif/ppp/chap.h
new file mode 100644
index 00000000..fedcab8d
--- /dev/null
+++ b/core/lwip/src/netif/ppp/chap.h
@@ -0,0 +1,150 @@
+/*****************************************************************************
+* chap.h - Network Challenge Handshake Authentication Protocol header file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* portions Copyright (c) 1998 Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 97-12-03 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
+*   Original built from BSD network code.
+******************************************************************************/
+/*
+ * chap.h - Challenge Handshake Authentication Protocol definitions.
+ *
+ * Copyright (c) 1993 The Australian National University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by the Australian National University.  The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * Copyright (c) 1991 Gregory M. Christy
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by the author.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * $Id: chap.h,v 1.6 2010/01/24 13:19:34 goldsimon Exp $
+ */
+
+#ifndef CHAP_H
+#define CHAP_H
+
+/* Code + ID + length */
+#define CHAP_HEADERLEN 4
+
+/*
+ * CHAP codes.
+ */
+
+#define CHAP_DIGEST_MD5      5    /* use MD5 algorithm */
+#define MD5_SIGNATURE_SIZE   16   /* 16 bytes in a MD5 message digest */
+#define CHAP_MICROSOFT       0x80 /* use Microsoft-compatible alg. */
+#define MS_CHAP_RESPONSE_LEN 49   /* Response length for MS-CHAP */
+
+#define CHAP_CHALLENGE       1
+#define CHAP_RESPONSE        2
+#define CHAP_SUCCESS         3
+#define CHAP_FAILURE         4
+
+/*
+ *  Challenge lengths (for challenges we send) and other limits.
+ */
+#define MIN_CHALLENGE_LENGTH 32
+#define MAX_CHALLENGE_LENGTH 64
+#define MAX_RESPONSE_LENGTH  64 /* sufficient for MD5 or MS-CHAP */
+
+/*
+ * Each interface is described by a chap structure.
+ */
+
+typedef struct chap_state {
+  int unit;                               /* Interface unit number */
+  int clientstate;                        /* Client state */
+  int serverstate;                        /* Server state */
+  u_char challenge[MAX_CHALLENGE_LENGTH]; /* last challenge string sent */
+  u_char chal_len;                        /* challenge length */
+  u_char chal_id;                         /* ID of last challenge */
+  u_char chal_type;                       /* hash algorithm for challenges */
+  u_char id;                              /* Current id */
+  char *chal_name;                        /* Our name to use with challenge */
+  int chal_interval;                      /* Time until we challenge peer again */
+  int timeouttime;                        /* Timeout time in seconds */
+  int max_transmits;                      /* Maximum # of challenge transmissions */
+  int chal_transmits;                     /* Number of transmissions of challenge */
+  int resp_transmits;                     /* Number of transmissions of response */
+  u_char response[MAX_RESPONSE_LENGTH];   /* Response to send */
+  u_char resp_length;                     /* length of response */
+  u_char resp_id;                         /* ID for response messages */
+  u_char resp_type;                       /* hash algorithm for responses */
+  char *resp_name;                        /* Our name to send with response */
+} chap_state;
+
+
+/*
+ * Client (peer) states.
+ */
+#define CHAPCS_INITIAL       0 /* Lower layer down, not opened */
+#define CHAPCS_CLOSED        1 /* Lower layer up, not opened */
+#define CHAPCS_PENDING       2 /* Auth us to peer when lower up */
+#define CHAPCS_LISTEN        3 /* Listening for a challenge */
+#define CHAPCS_RESPONSE      4 /* Sent response, waiting for status */
+#define CHAPCS_OPEN          5 /* We've received Success */
+
+/*
+ * Server (authenticator) states.
+ */
+#define CHAPSS_INITIAL       0 /* Lower layer down, not opened */
+#define CHAPSS_CLOSED        1 /* Lower layer up, not opened */
+#define CHAPSS_PENDING       2 /* Auth peer when lower up */
+#define CHAPSS_INITIAL_CHAL  3 /* We've sent the first challenge */
+#define CHAPSS_OPEN          4 /* We've sent a Success msg */
+#define CHAPSS_RECHALLENGE   5 /* We've sent another challenge */
+#define CHAPSS_BADAUTH       6 /* We've sent a Failure msg */
+
+extern chap_state chap[];
+
+void ChapAuthWithPeer (int, char *, u_char);
+void ChapAuthPeer (int, char *, u_char);
+
+extern struct protent chap_protent;
+
+#endif /* CHAP_H */
diff --git a/core/lwip/src/netif/ppp/chpms.c b/core/lwip/src/netif/ppp/chpms.c
new file mode 100644
index 00000000..83acefce
--- /dev/null
+++ b/core/lwip/src/netif/ppp/chpms.c
@@ -0,0 +1,396 @@
+/*** WARNING - THIS CODE HAS NOT BEEN FINISHED! ***/
+/*** The original PPPD code is written in a way to require either the UNIX DES
+     encryption functions encrypt(3) and setkey(3) or the DES library libdes.
+     Since both is not included in lwIP, MSCHAP currently does not work! */
+/*****************************************************************************
+* chpms.c - Network MicroSoft Challenge Handshake Authentication Protocol program file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* Copyright (c) 1997 by Global Election Systems Inc.  All rights reserved.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 97-12-08 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
+*   Original based on BSD chap_ms.c.
+*****************************************************************************/
+/*
+ * chap_ms.c - Microsoft MS-CHAP compatible implementation.
+ *
+ * Copyright (c) 1995 Eric Rosenquist, Strata Software Limited.
+ * http://www.strataware.com/
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Eric Rosenquist.  The name of the author may not be used to
+ * endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+/*
+ * Modifications by Lauri Pesonen / lpesonen@clinet.fi, april 1997
+ *
+ *   Implemented LANManager type password response to MS-CHAP challenges.
+ *   Now pppd provides both NT style and LANMan style blocks, and the
+ *   prefered is set by option "ms-lanman". Default is to use NT.
+ *   The hash text (StdText) was taken from Win95 RASAPI32.DLL.
+ *
+ *   You should also use DOMAIN\\USERNAME as described in README.MSCHAP80
+ */
+
+#define USE_CRYPT
+
+#include "lwip/opt.h"
+
+#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
+
+#if MSCHAP_SUPPORT /* don't build if not configured for use in lwipopts.h */
+
+#include "ppp.h"
+#include "pppdebug.h"
+
+#include "md4.h"
+#ifndef USE_CRYPT
+#include "des.h"
+#endif
+#include "chap.h"
+#include "chpms.h"
+
+#include <string.h>
+
+
+/*************************/
+/*** LOCAL DEFINITIONS ***/
+/*************************/
+
+
+/************************/
+/*** LOCAL DATA TYPES ***/
+/************************/
+typedef struct {
+    u_char LANManResp[24];
+    u_char NTResp[24];
+    u_char UseNT; /* If 1, ignore the LANMan response field */
+} MS_ChapResponse;
+/* We use MS_CHAP_RESPONSE_LEN, rather than sizeof(MS_ChapResponse),
+   in case this struct gets padded. */
+
+
+
+/***********************************/
+/*** LOCAL FUNCTION DECLARATIONS ***/
+/***********************************/
+
+/* XXX Don't know what to do with these. */
+extern void setkey(const char *);
+extern void encrypt(char *, int);
+
+static void DesEncrypt (u_char *, u_char *, u_char *);
+static void MakeKey (u_char *, u_char *);
+
+#ifdef USE_CRYPT
+static void Expand (u_char *, u_char *);
+static void Collapse (u_char *, u_char *);
+#endif
+
+static void ChallengeResponse(
+  u_char *challenge, /* IN   8 octets */
+  u_char *pwHash,    /* IN  16 octets */
+  u_char *response   /* OUT 24 octets */
+);
+static void ChapMS_NT(
+  char *rchallenge,
+  int rchallenge_len,
+  char *secret,
+  int secret_len,
+  MS_ChapResponse *response
+);
+static u_char Get7Bits(
+  u_char *input,
+  int startBit
+);
+
+static void
+ChallengeResponse( u_char *challenge, /* IN   8 octets */
+                   u_char *pwHash,    /* IN  16 octets */
+                   u_char *response   /* OUT 24 octets */)
+{
+  u_char    ZPasswordHash[21];
+
+  BZERO(ZPasswordHash, sizeof(ZPasswordHash));
+  BCOPY(pwHash, ZPasswordHash, 16);
+
+#if 0
+  log_packet(ZPasswordHash, sizeof(ZPasswordHash), "ChallengeResponse - ZPasswordHash", LOG_DEBUG);
+#endif
+
+  DesEncrypt(challenge, ZPasswordHash +  0, response + 0);
+  DesEncrypt(challenge, ZPasswordHash +  7, response + 8);
+  DesEncrypt(challenge, ZPasswordHash + 14, response + 16);
+
+#if 0
+  log_packet(response, 24, "ChallengeResponse - response", LOG_DEBUG);
+#endif
+}
+
+
+#ifdef USE_CRYPT
+static void
+DesEncrypt( u_char *clear, /* IN  8 octets */
+            u_char *key,   /* IN  7 octets */
+            u_char *cipher /* OUT 8 octets */)
+{
+  u_char des_key[8];
+  u_char crypt_key[66];
+  u_char des_input[66];
+
+  MakeKey(key, des_key);
+
+  Expand(des_key, crypt_key);
+  setkey((char*)crypt_key);
+
+#if 0
+  CHAPDEBUG(LOG_INFO, ("DesEncrypt: 8 octet input : %02X%02X%02X%02X%02X%02X%02X%02X\n",
+             clear[0], clear[1], clear[2], clear[3], clear[4], clear[5], clear[6], clear[7]));
+#endif
+
+  Expand(clear, des_input);
+  encrypt((char*)des_input, 0);
+  Collapse(des_input, cipher);
+
+#if 0
+  CHAPDEBUG(LOG_INFO, ("DesEncrypt: 8 octet output: %02X%02X%02X%02X%02X%02X%02X%02X\n",
+             cipher[0], cipher[1], cipher[2], cipher[3], cipher[4], cipher[5], cipher[6], cipher[7]));
+#endif
+}
+
+#else /* USE_CRYPT */
+
+static void
+DesEncrypt( u_char *clear, /* IN  8 octets */
+            u_char *key,   /* IN  7 octets */
+            u_char *cipher /* OUT 8 octets */)
+{
+  des_cblock    des_key;
+  des_key_schedule  key_schedule;
+
+  MakeKey(key, des_key);
+
+  des_set_key(&des_key, key_schedule);
+
+#if 0
+  CHAPDEBUG(LOG_INFO, ("DesEncrypt: 8 octet input : %02X%02X%02X%02X%02X%02X%02X%02X\n",
+             clear[0], clear[1], clear[2], clear[3], clear[4], clear[5], clear[6], clear[7]));
+#endif
+
+  des_ecb_encrypt((des_cblock *)clear, (des_cblock *)cipher, key_schedule, 1);
+
+#if 0
+  CHAPDEBUG(LOG_INFO, ("DesEncrypt: 8 octet output: %02X%02X%02X%02X%02X%02X%02X%02X\n",
+             cipher[0], cipher[1], cipher[2], cipher[3], cipher[4], cipher[5], cipher[6], cipher[7]));
+#endif
+}
+
+#endif /* USE_CRYPT */
+
+
+static u_char
+Get7Bits( u_char *input, int startBit)
+{
+  register unsigned int  word;
+
+  word  = (unsigned)input[startBit / 8] << 8;
+  word |= (unsigned)input[startBit / 8 + 1];
+
+  word >>= 15 - (startBit % 8 + 7);
+
+  return word & 0xFE;
+}
+
+#ifdef USE_CRYPT
+
+/* in == 8-byte string (expanded version of the 56-bit key)
+ * out == 64-byte string where each byte is either 1 or 0
+ * Note that the low-order "bit" is always ignored by by setkey()
+ */
+static void
+Expand(u_char *in, u_char *out)
+{
+  int j, c;
+  int i;
+
+  for(i = 0; i < 64; in++){
+    c = *in;
+    for(j = 7; j >= 0; j--) {
+      *out++ = (c >> j) & 01;
+    }
+    i += 8;
+  }
+}
+
+/* The inverse of Expand
+ */
+static void
+Collapse(u_char *in, u_char *out)
+{
+  int j;
+  int i;
+  unsigned int c;
+
+  for (i = 0; i < 64; i += 8, out++) {
+    c = 0;
+    for (j = 7; j >= 0; j--, in++) {
+      c |= *in << j;
+    }
+    *out = c & 0xff;
+  }
+}
+#endif
+
+static void
+MakeKey( u_char *key,    /* IN  56 bit DES key missing parity bits */
+         u_char *des_key /* OUT 64 bit DES key with parity bits added */)
+{
+  des_key[0] = Get7Bits(key,  0);
+  des_key[1] = Get7Bits(key,  7);
+  des_key[2] = Get7Bits(key, 14);
+  des_key[3] = Get7Bits(key, 21);
+  des_key[4] = Get7Bits(key, 28);
+  des_key[5] = Get7Bits(key, 35);
+  des_key[6] = Get7Bits(key, 42);
+  des_key[7] = Get7Bits(key, 49);
+  
+#ifndef USE_CRYPT
+  des_set_odd_parity((des_cblock *)des_key);
+#endif
+  
+#if 0
+  CHAPDEBUG(LOG_INFO, ("MakeKey: 56-bit input : %02X%02X%02X%02X%02X%02X%02X\n",
+             key[0], key[1], key[2], key[3], key[4], key[5], key[6]));
+  CHAPDEBUG(LOG_INFO, ("MakeKey: 64-bit output: %02X%02X%02X%02X%02X%02X%02X%02X\n",
+             des_key[0], des_key[1], des_key[2], des_key[3], des_key[4], des_key[5], des_key[6], des_key[7]));
+#endif
+}
+
+static void
+ChapMS_NT( char *rchallenge,
+           int rchallenge_len,
+           char *secret,
+           int secret_len,
+           MS_ChapResponse *response)
+{
+  int      i;
+  MDstruct  md4Context;
+  u_char    unicodePassword[MAX_NT_PASSWORD * 2];
+  static int  low_byte_first = -1;
+
+  LWIP_UNUSED_ARG(rchallenge_len);
+
+  /* Initialize the Unicode version of the secret (== password). */
+  /* This implicitly supports 8-bit ISO8859/1 characters. */
+  BZERO(unicodePassword, sizeof(unicodePassword));
+  for (i = 0; i < secret_len; i++) {
+    unicodePassword[i * 2] = (u_char)secret[i];
+  }
+  MDbegin(&md4Context);
+  MDupdate(&md4Context, unicodePassword, secret_len * 2 * 8);  /* Unicode is 2 bytes/char, *8 for bit count */
+
+  if (low_byte_first == -1) {
+    low_byte_first = (PP_HTONS((unsigned short int)1) != 1);
+  }
+  if (low_byte_first == 0) {
+    /* @todo: arg type - u_long* or u_int* ? */
+    MDreverse((unsigned int*)&md4Context);  /*  sfb 961105 */
+  }
+
+  MDupdate(&md4Context, NULL, 0);  /* Tell MD4 we're done */
+
+  ChallengeResponse((u_char*)rchallenge, (u_char*)md4Context.buffer, response->NTResp);
+}
+
+#ifdef MSLANMAN
+static u_char *StdText = (u_char *)"KGS!@#$%"; /* key from rasapi32.dll */
+
+static void
+ChapMS_LANMan( char *rchallenge,
+               int rchallenge_len,
+               char *secret,
+               int secret_len,
+               MS_ChapResponse  *response)
+{
+  int      i;
+  u_char    UcasePassword[MAX_NT_PASSWORD]; /* max is actually 14 */
+  u_char    PasswordHash[16];
+  
+  /* LANMan password is case insensitive */
+  BZERO(UcasePassword, sizeof(UcasePassword));
+  for (i = 0; i < secret_len; i++) {
+    UcasePassword[i] = (u_char)toupper(secret[i]);
+  }
+  DesEncrypt( StdText, UcasePassword + 0, PasswordHash + 0 );
+  DesEncrypt( StdText, UcasePassword + 7, PasswordHash + 8 );
+  ChallengeResponse(rchallenge, PasswordHash, response->LANManResp);
+}
+#endif
+
+void
+ChapMS( chap_state *cstate, char *rchallenge, int rchallenge_len, char *secret, int secret_len)
+{
+  MS_ChapResponse response;
+#ifdef MSLANMAN
+  extern int ms_lanman;
+#endif
+
+#if 0
+  CHAPDEBUG(LOG_INFO, ("ChapMS: secret is '%.*s'\n", secret_len, secret));
+#endif
+  BZERO(&response, sizeof(response));
+
+  /* Calculate both always */
+  ChapMS_NT(rchallenge, rchallenge_len, secret, secret_len, &response);
+
+#ifdef MSLANMAN
+  ChapMS_LANMan(rchallenge, rchallenge_len, secret, secret_len, &response);
+
+  /* prefered method is set by option  */
+  response.UseNT = !ms_lanman;
+#else
+  response.UseNT = 1;
+#endif
+
+  BCOPY(&response, cstate->response, MS_CHAP_RESPONSE_LEN);
+  cstate->resp_length = MS_CHAP_RESPONSE_LEN;
+}
+
+#endif /* MSCHAP_SUPPORT */
+
+#endif /* PPP_SUPPORT */
diff --git a/core/lwip/src/netif/ppp/chpms.h b/core/lwip/src/netif/ppp/chpms.h
new file mode 100644
index 00000000..df070fb3
--- /dev/null
+++ b/core/lwip/src/netif/ppp/chpms.h
@@ -0,0 +1,64 @@
+/*****************************************************************************
+* chpms.h - Network Microsoft Challenge Handshake Protocol header file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* portions Copyright (c) 1998 Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 98-01-30 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
+*   Original built from BSD network code.
+******************************************************************************/
+/*
+ * chap.h - Challenge Handshake Authentication Protocol definitions.
+ *
+ * Copyright (c) 1995 Eric Rosenquist, Strata Software Limited.
+ * http://www.strataware.com/
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Eric Rosenquist.  The name of the author may not be used to
+ * endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * $Id: chpms.h,v 1.5 2007/12/19 20:47:23 fbernon Exp $
+ */
+
+#ifndef CHPMS_H
+#define CHPMS_H
+
+#define MAX_NT_PASSWORD 256 /* Maximum number of (Unicode) chars in an NT password */
+
+void ChapMS (chap_state *, char *, int, char *, int);
+
+#endif /* CHPMS_H */
diff --git a/core/lwip/src/netif/ppp/fsm.c b/core/lwip/src/netif/ppp/fsm.c
new file mode 100644
index 00000000..2e73c5af
--- /dev/null
+++ b/core/lwip/src/netif/ppp/fsm.c
@@ -0,0 +1,890 @@
+/*****************************************************************************
+* fsm.c - Network Control Protocol Finite State Machine program file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* portions Copyright (c) 1997 by Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 97-12-01 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
+*   Original based on BSD fsm.c.
+*****************************************************************************/
+/*
+ * fsm.c - {Link, IP} Control Protocol Finite State Machine.
+ *
+ * Copyright (c) 1989 Carnegie Mellon University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Carnegie Mellon University.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+/*
+ * TODO:
+ * Randomize fsm id on link/init.
+ * Deal with variable outgoing MTU.
+ */
+
+#include "lwip/opt.h"
+
+#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
+
+#include "ppp.h"
+#include "pppdebug.h"
+
+#include "fsm.h"
+
+#include <string.h>
+
+#if PPP_DEBUG
+static const char *ppperr_strerr[] = {
+           "LS_INITIAL",  /* LS_INITIAL  0 */
+           "LS_STARTING", /* LS_STARTING 1 */
+           "LS_CLOSED",   /* LS_CLOSED   2 */
+           "LS_STOPPED",  /* LS_STOPPED  3 */
+           "LS_CLOSING",  /* LS_CLOSING  4 */
+           "LS_STOPPING", /* LS_STOPPING 5 */
+           "LS_REQSENT",  /* LS_REQSENT  6 */
+           "LS_ACKRCVD",  /* LS_ACKRCVD  7 */
+           "LS_ACKSENT",  /* LS_ACKSENT  8 */
+           "LS_OPENED"    /* LS_OPENED   9 */
+};
+#endif /* PPP_DEBUG */
+
+static void fsm_timeout (void *);
+static void fsm_rconfreq (fsm *, u_char, u_char *, int);
+static void fsm_rconfack (fsm *, int, u_char *, int);
+static void fsm_rconfnakrej (fsm *, int, int, u_char *, int);
+static void fsm_rtermreq (fsm *, int, u_char *, int);
+static void fsm_rtermack (fsm *);
+static void fsm_rcoderej (fsm *, u_char *, int);
+static void fsm_sconfreq (fsm *, int);
+
+#define PROTO_NAME(f) ((f)->callbacks->proto_name)
+
+int peer_mru[NUM_PPP];
+
+
+/*
+ * fsm_init - Initialize fsm.
+ *
+ * Initialize fsm state.
+ */
+void
+fsm_init(fsm *f)
+{
+  f->state = LS_INITIAL;
+  f->flags = 0;
+  f->id = 0;        /* XXX Start with random id? */
+  f->timeouttime = FSM_DEFTIMEOUT;
+  f->maxconfreqtransmits = FSM_DEFMAXCONFREQS;
+  f->maxtermtransmits = FSM_DEFMAXTERMREQS;
+  f->maxnakloops = FSM_DEFMAXNAKLOOPS;
+  f->term_reason_len = 0;
+}
+
+
+/*
+ * fsm_lowerup - The lower layer is up.
+ */
+void
+fsm_lowerup(fsm *f)
+{
+  int oldState = f->state;
+
+  LWIP_UNUSED_ARG(oldState);
+
+  switch( f->state ) {
+    case LS_INITIAL:
+      f->state = LS_CLOSED;
+      break;
+
+    case LS_STARTING:
+      if( f->flags & OPT_SILENT ) {
+        f->state = LS_STOPPED;
+      } else {
+        /* Send an initial configure-request */
+        fsm_sconfreq(f, 0);
+        f->state = LS_REQSENT;
+      }
+    break;
+
+    default:
+      FSMDEBUG(LOG_INFO, ("%s: Up event in state %d (%s)!\n",
+          PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
+  }
+
+  FSMDEBUG(LOG_INFO, ("%s: lowerup state %d (%s) -> %d (%s)\n",
+      PROTO_NAME(f), oldState, ppperr_strerr[oldState], f->state, ppperr_strerr[f->state]));
+}
+
+
+/*
+ * fsm_lowerdown - The lower layer is down.
+ *
+ * Cancel all timeouts and inform upper layers.
+ */
+void
+fsm_lowerdown(fsm *f)
+{
+  int oldState = f->state;
+
+  LWIP_UNUSED_ARG(oldState);
+
+  switch( f->state ) {
+    case LS_CLOSED:
+      f->state = LS_INITIAL;
+      break;
+
+    case LS_STOPPED:
+      f->state = LS_STARTING;
+      if( f->callbacks->starting ) {
+        (*f->callbacks->starting)(f);
+      }
+      break;
+
+    case LS_CLOSING:
+      f->state = LS_INITIAL;
+      UNTIMEOUT(fsm_timeout, f);  /* Cancel timeout */
+      break;
+
+    case LS_STOPPING:
+    case LS_REQSENT:
+    case LS_ACKRCVD:
+    case LS_ACKSENT:
+      f->state = LS_STARTING;
+      UNTIMEOUT(fsm_timeout, f);  /* Cancel timeout */
+      break;
+
+    case LS_OPENED:
+      if( f->callbacks->down ) {
+        (*f->callbacks->down)(f);
+      }
+      f->state = LS_STARTING;
+      break;
+
+    default:
+      FSMDEBUG(LOG_INFO, ("%s: Down event in state %d (%s)!\n",
+          PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
+  }
+
+  FSMDEBUG(LOG_INFO, ("%s: lowerdown state %d (%s) -> %d (%s)\n",
+      PROTO_NAME(f), oldState, ppperr_strerr[oldState], f->state, ppperr_strerr[f->state]));
+}
+
+
+/*
+ * fsm_open - Link is allowed to come up.
+ */
+void
+fsm_open(fsm *f)
+{
+  int oldState = f->state;
+
+  LWIP_UNUSED_ARG(oldState);
+
+  switch( f->state ) {
+    case LS_INITIAL:
+      f->state = LS_STARTING;
+      if( f->callbacks->starting ) {
+        (*f->callbacks->starting)(f);
+      }
+      break;
+
+    case LS_CLOSED:
+      if( f->flags & OPT_SILENT ) {
+        f->state = LS_STOPPED;
+      } else {
+        /* Send an initial configure-request */
+        fsm_sconfreq(f, 0);
+        f->state = LS_REQSENT;
+      }
+      break;
+  
+    case LS_CLOSING:
+      f->state = LS_STOPPING;
+      /* fall through */
+    case LS_STOPPED:
+    case LS_OPENED:
+      if( f->flags & OPT_RESTART ) {
+        fsm_lowerdown(f);
+        fsm_lowerup(f);
+      }
+      break;
+  }
+
+  FSMDEBUG(LOG_INFO, ("%s: open state %d (%s) -> %d (%s)\n",
+      PROTO_NAME(f), oldState, ppperr_strerr[oldState], f->state, ppperr_strerr[f->state]));
+}
+
+#if 0 /* backport pppd 2.4.4b1; */
+/*
+ * terminate_layer - Start process of shutting down the FSM
+ *
+ * Cancel any timeout running, notify upper layers we're done, and
+ * send a terminate-request message as configured.
+ */
+static void
+terminate_layer(fsm *f, int nextstate)
+{
+  /* @todo */
+}
+#endif
+
+/*
+ * fsm_close - Start closing connection.
+ *
+ * Cancel timeouts and either initiate close or possibly go directly to
+ * the LS_CLOSED state.
+ */
+void
+fsm_close(fsm *f, char *reason)
+{
+  int oldState = f->state;
+
+  LWIP_UNUSED_ARG(oldState);
+
+  f->term_reason = reason;
+  f->term_reason_len = (reason == NULL ? 0 : (int)strlen(reason));
+  switch( f->state ) {
+    case LS_STARTING:
+      f->state = LS_INITIAL;
+      break;
+    case LS_STOPPED:
+      f->state = LS_CLOSED;
+      break;
+    case LS_STOPPING:
+      f->state = LS_CLOSING;
+      break;
+
+    case LS_REQSENT:
+    case LS_ACKRCVD:
+    case LS_ACKSENT:
+    case LS_OPENED:
+      if( f->state != LS_OPENED ) {
+        UNTIMEOUT(fsm_timeout, f);  /* Cancel timeout */
+      } else if( f->callbacks->down ) {
+        (*f->callbacks->down)(f);  /* Inform upper layers we're down */
+      }
+      /* Init restart counter, send Terminate-Request */
+      f->retransmits = f->maxtermtransmits;
+      fsm_sdata(f, TERMREQ, f->reqid = ++f->id,
+            (u_char *) f->term_reason, f->term_reason_len);
+      TIMEOUT(fsm_timeout, f, f->timeouttime);
+      --f->retransmits;
+
+      f->state = LS_CLOSING;
+      break;
+  }
+
+  FSMDEBUG(LOG_INFO, ("%s: close reason=%s state %d (%s) -> %d (%s)\n",
+      PROTO_NAME(f), reason, oldState, ppperr_strerr[oldState], f->state, ppperr_strerr[f->state]));
+}
+
+
+/*
+ * fsm_timeout - Timeout expired.
+ */
+static void
+fsm_timeout(void *arg)
+{
+  fsm *f = (fsm *) arg;
+
+  switch (f->state) {
+    case LS_CLOSING:
+    case LS_STOPPING:
+      if( f->retransmits <= 0 ) {
+        FSMDEBUG(LOG_WARNING, ("%s: timeout sending Terminate-Request state=%d (%s)\n",
+             PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
+        /*
+         * We've waited for an ack long enough.  Peer probably heard us.
+         */
+        f->state = (f->state == LS_CLOSING)? LS_CLOSED: LS_STOPPED;
+        if( f->callbacks->finished ) {
+          (*f->callbacks->finished)(f);
+        }
+      } else {
+        FSMDEBUG(LOG_WARNING, ("%s: timeout resending Terminate-Requests state=%d (%s)\n",
+             PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
+        /* Send Terminate-Request */
+        fsm_sdata(f, TERMREQ, f->reqid = ++f->id,
+            (u_char *) f->term_reason, f->term_reason_len);
+        TIMEOUT(fsm_timeout, f, f->timeouttime);
+        --f->retransmits;
+      }
+      break;
+
+    case LS_REQSENT:
+    case LS_ACKRCVD:
+    case LS_ACKSENT:
+      if (f->retransmits <= 0) {
+        FSMDEBUG(LOG_WARNING, ("%s: timeout sending Config-Requests state=%d (%s)\n",
+         PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
+        f->state = LS_STOPPED;
+        if( (f->flags & OPT_PASSIVE) == 0 && f->callbacks->finished ) {
+          (*f->callbacks->finished)(f);
+        }
+      } else {
+        FSMDEBUG(LOG_WARNING, ("%s: timeout resending Config-Request state=%d (%s)\n",
+         PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
+        /* Retransmit the configure-request */
+        if (f->callbacks->retransmit) {
+          (*f->callbacks->retransmit)(f);
+        }
+        fsm_sconfreq(f, 1);    /* Re-send Configure-Request */
+        if( f->state == LS_ACKRCVD ) {
+          f->state = LS_REQSENT;
+        }
+      }
+      break;
+
+    default:
+      FSMDEBUG(LOG_INFO, ("%s: UNHANDLED timeout event in state %d (%s)!\n",
+          PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
+  }
+}
+
+
+/*
+ * fsm_input - Input packet.
+ */
+void
+fsm_input(fsm *f, u_char *inpacket, int l)
+{
+  u_char *inp = inpacket;
+  u_char code, id;
+  int len;
+
+  /*
+  * Parse header (code, id and length).
+  * If packet too short, drop it.
+  */
+  if (l < HEADERLEN) {
+    FSMDEBUG(LOG_WARNING, ("fsm_input(%x): Rcvd short header.\n",
+          f->protocol));
+    return;
+  }
+  GETCHAR(code, inp);
+  GETCHAR(id, inp);
+  GETSHORT(len, inp);
+  if (len < HEADERLEN) {
+    FSMDEBUG(LOG_INFO, ("fsm_input(%x): Rcvd illegal length.\n",
+        f->protocol));
+    return;
+  }
+  if (len > l) {
+    FSMDEBUG(LOG_INFO, ("fsm_input(%x): Rcvd short packet.\n",
+        f->protocol));
+    return;
+  }
+  len -= HEADERLEN;    /* subtract header length */
+
+  if( f->state == LS_INITIAL || f->state == LS_STARTING ) {
+    FSMDEBUG(LOG_INFO, ("fsm_input(%x): Rcvd packet in state %d (%s).\n",
+        f->protocol, f->state, ppperr_strerr[f->state]));
+    return;
+  }
+  FSMDEBUG(LOG_INFO, ("fsm_input(%s):%d,%d,%d\n", PROTO_NAME(f), code, id, l));
+  /*
+   * Action depends on code.
+   */
+  switch (code) {
+    case CONFREQ:
+      fsm_rconfreq(f, id, inp, len);
+      break;
+    
+    case CONFACK:
+      fsm_rconfack(f, id, inp, len);
+      break;
+    
+    case CONFNAK:
+    case CONFREJ:
+      fsm_rconfnakrej(f, code, id, inp, len);
+      break;
+    
+    case TERMREQ:
+      fsm_rtermreq(f, id, inp, len);
+      break;
+    
+    case TERMACK:
+      fsm_rtermack(f);
+      break;
+    
+    case CODEREJ:
+      fsm_rcoderej(f, inp, len);
+      break;
+    
+    default:
+      FSMDEBUG(LOG_INFO, ("fsm_input(%s): default: \n", PROTO_NAME(f)));
+      if( !f->callbacks->extcode ||
+          !(*f->callbacks->extcode)(f, code, id, inp, len) ) {
+        fsm_sdata(f, CODEREJ, ++f->id, inpacket, len + HEADERLEN);
+      }
+      break;
+  }
+}
+
+
+/*
+ * fsm_rconfreq - Receive Configure-Request.
+ */
+static void
+fsm_rconfreq(fsm *f, u_char id, u_char *inp, int len)
+{
+  int code, reject_if_disagree;
+
+  FSMDEBUG(LOG_INFO, ("fsm_rconfreq(%s): Rcvd id %d state=%d (%s)\n", 
+        PROTO_NAME(f), id, f->state, ppperr_strerr[f->state]));
+  switch( f->state ) {
+    case LS_CLOSED:
+      /* Go away, we're closed */
+      fsm_sdata(f, TERMACK, id, NULL, 0);
+      return;
+    case LS_CLOSING:
+    case LS_STOPPING:
+      return;
+
+    case LS_OPENED:
+      /* Go down and restart negotiation */
+      if( f->callbacks->down ) {
+        (*f->callbacks->down)(f);  /* Inform upper layers */
+      }
+      fsm_sconfreq(f, 0);    /* Send initial Configure-Request */
+      break;
+
+    case LS_STOPPED:
+      /* Negotiation started by our peer */
+      fsm_sconfreq(f, 0);    /* Send initial Configure-Request */
+      f->state = LS_REQSENT;
+      break;
+  }
+  
+  /*
+  * Pass the requested configuration options
+  * to protocol-specific code for checking.
+  */
+  if (f->callbacks->reqci) {    /* Check CI */
+    reject_if_disagree = (f->nakloops >= f->maxnakloops);
+    code = (*f->callbacks->reqci)(f, inp, &len, reject_if_disagree);
+  } else if (len) {
+    code = CONFREJ;      /* Reject all CI */
+  } else {
+    code = CONFACK;
+  }
+  
+  /* send the Ack, Nak or Rej to the peer */
+  fsm_sdata(f, (u_char)code, id, inp, len);
+  
+  if (code == CONFACK) {
+    if (f->state == LS_ACKRCVD) {
+      UNTIMEOUT(fsm_timeout, f);  /* Cancel timeout */
+      f->state = LS_OPENED;
+      if (f->callbacks->up) {
+        (*f->callbacks->up)(f);  /* Inform upper layers */
+      }
+    } else {
+      f->state = LS_ACKSENT;
+    }
+    f->nakloops = 0;
+  } else {
+    /* we sent CONFACK or CONFREJ */
+    if (f->state != LS_ACKRCVD) {
+      f->state = LS_REQSENT;
+    }
+    if( code == CONFNAK ) {
+      ++f->nakloops;
+    }
+  }
+}
+
+
+/*
+ * fsm_rconfack - Receive Configure-Ack.
+ */
+static void
+fsm_rconfack(fsm *f, int id, u_char *inp, int len)
+{
+  FSMDEBUG(LOG_INFO, ("fsm_rconfack(%s): Rcvd id %d state=%d (%s)\n",
+        PROTO_NAME(f), id, f->state, ppperr_strerr[f->state]));
+  
+  if (id != f->reqid || f->seen_ack) {   /* Expected id? */
+    return; /* Nope, toss... */
+  }
+  if( !(f->callbacks->ackci? (*f->callbacks->ackci)(f, inp, len): (len == 0)) ) {
+    /* Ack is bad - ignore it */
+    FSMDEBUG(LOG_INFO, ("%s: received bad Ack (length %d)\n",
+          PROTO_NAME(f), len));
+    return;
+  }
+  f->seen_ack = 1;
+  
+  switch (f->state) {
+    case LS_CLOSED:
+    case LS_STOPPED:
+      fsm_sdata(f, TERMACK, (u_char)id, NULL, 0);
+      break;
+    
+    case LS_REQSENT:
+      f->state = LS_ACKRCVD;
+      f->retransmits = f->maxconfreqtransmits;
+      break;
+    
+    case LS_ACKRCVD:
+      /* Huh? an extra valid Ack? oh well... */
+      UNTIMEOUT(fsm_timeout, f);  /* Cancel timeout */
+      fsm_sconfreq(f, 0);
+      f->state = LS_REQSENT;
+      break;
+    
+    case LS_ACKSENT:
+      UNTIMEOUT(fsm_timeout, f);  /* Cancel timeout */
+      f->state = LS_OPENED;
+      f->retransmits = f->maxconfreqtransmits;
+      if (f->callbacks->up) {
+        (*f->callbacks->up)(f);  /* Inform upper layers */
+      }
+      break;
+    
+    case LS_OPENED:
+      /* Go down and restart negotiation */
+      if (f->callbacks->down) {
+        (*f->callbacks->down)(f);  /* Inform upper layers */
+      }
+      fsm_sconfreq(f, 0);    /* Send initial Configure-Request */
+      f->state = LS_REQSENT;
+      break;
+  }
+}
+
+
+/*
+ * fsm_rconfnakrej - Receive Configure-Nak or Configure-Reject.
+ */
+static void
+fsm_rconfnakrej(fsm *f, int code, int id, u_char *inp, int len)
+{
+  int (*proc) (fsm *, u_char *, int);
+  int ret;
+
+  FSMDEBUG(LOG_INFO, ("fsm_rconfnakrej(%s): Rcvd id %d state=%d (%s)\n",
+        PROTO_NAME(f), id, f->state, ppperr_strerr[f->state]));
+
+  if (id != f->reqid || f->seen_ack) { /* Expected id? */
+    return;        /* Nope, toss... */
+  }
+  proc = (code == CONFNAK)? f->callbacks->nakci: f->callbacks->rejci;
+  if (!proc || !((ret = proc(f, inp, len)))) {
+    /* Nak/reject is bad - ignore it */
+    FSMDEBUG(LOG_INFO, ("%s: received bad %s (length %d)\n",
+          PROTO_NAME(f), (code==CONFNAK? "Nak": "reject"), len));
+    return;
+  }
+  f->seen_ack = 1;
+
+  switch (f->state) {
+    case LS_CLOSED:
+    case LS_STOPPED:
+      fsm_sdata(f, TERMACK, (u_char)id, NULL, 0);
+      break;
+    
+    case LS_REQSENT:
+    case LS_ACKSENT:
+      /* They didn't agree to what we wanted - try another request */
+      UNTIMEOUT(fsm_timeout, f);  /* Cancel timeout */
+      if (ret < 0) {
+        f->state = LS_STOPPED;    /* kludge for stopping CCP */
+      } else {
+        fsm_sconfreq(f, 0);    /* Send Configure-Request */
+      }
+      break;
+    
+    case LS_ACKRCVD:
+      /* Got a Nak/reject when we had already had an Ack?? oh well... */
+      UNTIMEOUT(fsm_timeout, f);  /* Cancel timeout */
+      fsm_sconfreq(f, 0);
+      f->state = LS_REQSENT;
+      break;
+    
+    case LS_OPENED:
+      /* Go down and restart negotiation */
+      if (f->callbacks->down) {
+        (*f->callbacks->down)(f);  /* Inform upper layers */
+      }
+      fsm_sconfreq(f, 0);    /* Send initial Configure-Request */
+      f->state = LS_REQSENT;
+      break;
+  }
+}
+
+
+/*
+ * fsm_rtermreq - Receive Terminate-Req.
+ */
+static void
+fsm_rtermreq(fsm *f, int id, u_char *p, int len)
+{
+  LWIP_UNUSED_ARG(p);
+
+  FSMDEBUG(LOG_INFO, ("fsm_rtermreq(%s): Rcvd id %d state=%d (%s)\n",
+        PROTO_NAME(f), id, f->state, ppperr_strerr[f->state]));
+
+  switch (f->state) {
+    case LS_ACKRCVD:
+    case LS_ACKSENT:
+      f->state = LS_REQSENT;    /* Start over but keep trying */
+      break;
+
+    case LS_OPENED:
+      if (len > 0) {
+        FSMDEBUG(LOG_INFO, ("%s terminated by peer (%p)\n", PROTO_NAME(f), p));
+      } else {
+        FSMDEBUG(LOG_INFO, ("%s terminated by peer\n", PROTO_NAME(f)));
+      }
+      if (f->callbacks->down) {
+        (*f->callbacks->down)(f);  /* Inform upper layers */
+      }
+      f->retransmits = 0;
+      f->state = LS_STOPPING;
+      TIMEOUT(fsm_timeout, f, f->timeouttime);
+      break;
+  }
+
+  fsm_sdata(f, TERMACK, (u_char)id, NULL, 0);
+}
+
+
+/*
+ * fsm_rtermack - Receive Terminate-Ack.
+ */
+static void
+fsm_rtermack(fsm *f)
+{
+  FSMDEBUG(LOG_INFO, ("fsm_rtermack(%s): state=%d (%s)\n", 
+        PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
+  
+  switch (f->state) {
+    case LS_CLOSING:
+      UNTIMEOUT(fsm_timeout, f);
+      f->state = LS_CLOSED;
+      if( f->callbacks->finished ) {
+        (*f->callbacks->finished)(f);
+      }
+      break;
+
+    case LS_STOPPING:
+      UNTIMEOUT(fsm_timeout, f);
+      f->state = LS_STOPPED;
+      if( f->callbacks->finished ) {
+        (*f->callbacks->finished)(f);
+      }
+      break;
+    
+    case LS_ACKRCVD:
+      f->state = LS_REQSENT;
+      break;
+    
+    case LS_OPENED:
+      if (f->callbacks->down) {
+        (*f->callbacks->down)(f);  /* Inform upper layers */
+      }
+      fsm_sconfreq(f, 0);
+      break;
+    default:
+      FSMDEBUG(LOG_INFO, ("fsm_rtermack(%s): UNHANDLED state=%d (%s)!!!\n", 
+                PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
+  }
+}
+
+
+/*
+ * fsm_rcoderej - Receive an Code-Reject.
+ */
+static void
+fsm_rcoderej(fsm *f, u_char *inp, int len)
+{
+  u_char code, id;
+  
+  FSMDEBUG(LOG_INFO, ("fsm_rcoderej(%s): state=%d (%s)\n", 
+        PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
+  
+  if (len < HEADERLEN) {
+    FSMDEBUG(LOG_INFO, ("fsm_rcoderej: Rcvd short Code-Reject packet!\n"));
+    return;
+  }
+  GETCHAR(code, inp);
+  GETCHAR(id, inp);
+  FSMDEBUG(LOG_WARNING, ("%s: Rcvd Code-Reject for code %d, id %d\n",
+        PROTO_NAME(f), code, id));
+  
+  if( f->state == LS_ACKRCVD ) {
+    f->state = LS_REQSENT;
+  }
+}
+
+
+/*
+ * fsm_protreject - Peer doesn't speak this protocol.
+ *
+ * Treat this as a catastrophic error (RXJ-).
+ */
+void
+fsm_protreject(fsm *f)
+{
+  switch( f->state ) {
+    case LS_CLOSING:
+      UNTIMEOUT(fsm_timeout, f);  /* Cancel timeout */
+      /* fall through */
+    case LS_CLOSED:
+      f->state = LS_CLOSED;
+      if( f->callbacks->finished ) {
+        (*f->callbacks->finished)(f);
+      }
+      break;
+
+    case LS_STOPPING:
+    case LS_REQSENT:
+    case LS_ACKRCVD:
+    case LS_ACKSENT:
+      UNTIMEOUT(fsm_timeout, f);  /* Cancel timeout */
+      /* fall through */
+    case LS_STOPPED:
+      f->state = LS_STOPPED;
+      if( f->callbacks->finished ) {
+        (*f->callbacks->finished)(f);
+      }
+      break;
+    
+    case LS_OPENED:
+      if( f->callbacks->down ) {
+        (*f->callbacks->down)(f);
+      }
+      /* Init restart counter, send Terminate-Request */
+      f->retransmits = f->maxtermtransmits;
+      fsm_sdata(f, TERMREQ, f->reqid = ++f->id,
+            (u_char *) f->term_reason, f->term_reason_len);
+      TIMEOUT(fsm_timeout, f, f->timeouttime);
+      --f->retransmits;
+
+      f->state = LS_STOPPING;
+      break;
+    
+    default:
+      FSMDEBUG(LOG_INFO, ("%s: Protocol-reject event in state %d (%s)!\n",
+            PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
+    }
+}
+
+
+/*
+ * fsm_sconfreq - Send a Configure-Request.
+ */
+static void
+fsm_sconfreq(fsm *f, int retransmit)
+{
+  u_char *outp;
+  int cilen;
+  
+  if( f->state != LS_REQSENT && f->state != LS_ACKRCVD && f->state != LS_ACKSENT ) {
+    /* Not currently negotiating - reset options */
+    if( f->callbacks->resetci ) {
+      (*f->callbacks->resetci)(f);
+    }
+    f->nakloops = 0;
+  }
+  
+  if( !retransmit ) {
+    /* New request - reset retransmission counter, use new ID */
+    f->retransmits = f->maxconfreqtransmits;
+    f->reqid = ++f->id;
+  }
+  
+  f->seen_ack = 0;
+  
+  /*
+   * Make up the request packet
+   */
+  outp = outpacket_buf[f->unit] + PPP_HDRLEN + HEADERLEN;
+  if( f->callbacks->cilen && f->callbacks->addci ) {
+    cilen = (*f->callbacks->cilen)(f);
+    if( cilen > peer_mru[f->unit] - (int)HEADERLEN ) {
+      cilen = peer_mru[f->unit] - HEADERLEN;
+    }
+    if (f->callbacks->addci) {
+      (*f->callbacks->addci)(f, outp, &cilen);
+    }
+  } else {
+    cilen = 0;
+  }
+
+  /* send the request to our peer */
+  fsm_sdata(f, CONFREQ, f->reqid, outp, cilen);
+  
+  /* start the retransmit timer */
+  --f->retransmits;
+  TIMEOUT(fsm_timeout, f, f->timeouttime);
+  
+  FSMDEBUG(LOG_INFO, ("%s: sending Configure-Request, id %d\n",
+        PROTO_NAME(f), f->reqid));
+}
+
+
+/*
+ * fsm_sdata - Send some data.
+ *
+ * Used for all packets sent to our peer by this module.
+ */
+void
+fsm_sdata( fsm *f, u_char code, u_char id, u_char *data, int datalen)
+{
+  u_char *outp;
+  int outlen;
+
+  /* Adjust length to be smaller than MTU */
+  outp = outpacket_buf[f->unit];
+  if (datalen > peer_mru[f->unit] - (int)HEADERLEN) {
+    datalen = peer_mru[f->unit] - HEADERLEN;
+  }
+  if (datalen && data != outp + PPP_HDRLEN + HEADERLEN) {
+    BCOPY(data, outp + PPP_HDRLEN + HEADERLEN, datalen);
+  }
+  outlen = datalen + HEADERLEN;
+  MAKEHEADER(outp, f->protocol);
+  PUTCHAR(code, outp);
+  PUTCHAR(id, outp);
+  PUTSHORT(outlen, outp);
+  pppWrite(f->unit, outpacket_buf[f->unit], outlen + PPP_HDRLEN);
+  FSMDEBUG(LOG_INFO, ("fsm_sdata(%s): Sent code %d,%d,%d.\n",
+        PROTO_NAME(f), code, id, outlen));
+}
+
+#endif /* PPP_SUPPORT */
diff --git a/core/lwip/src/netif/ppp/fsm.h b/core/lwip/src/netif/ppp/fsm.h
new file mode 100644
index 00000000..8d41b5f5
--- /dev/null
+++ b/core/lwip/src/netif/ppp/fsm.h
@@ -0,0 +1,157 @@
+/*****************************************************************************
+* fsm.h - Network Control Protocol Finite State Machine header file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* Copyright (c) 1997 Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 97-11-05 Guy Lancaster <glanca@gesn.com>, Global Election Systems Inc.
+*   Original based on BSD code.
+*****************************************************************************/
+/*
+ * fsm.h - {Link, IP} Control Protocol Finite State Machine definitions.
+ *
+ * Copyright (c) 1989 Carnegie Mellon University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Carnegie Mellon University.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * $Id: fsm.h,v 1.5 2009/12/31 17:08:08 goldsimon Exp $
+ */
+
+#ifndef FSM_H
+#define FSM_H
+
+/*
+ * LCP Packet header = Code, id, length.
+ */
+#define HEADERLEN (sizeof (u_char) + sizeof (u_char) + sizeof (u_short))
+
+
+/*
+ *  CP (LCP, IPCP, etc.) codes.
+ */
+#define CONFREQ     1 /* Configuration Request */
+#define CONFACK     2 /* Configuration Ack */
+#define CONFNAK     3 /* Configuration Nak */
+#define CONFREJ     4 /* Configuration Reject */
+#define TERMREQ     5 /* Termination Request */
+#define TERMACK     6 /* Termination Ack */
+#define CODEREJ     7 /* Code Reject */
+
+
+/*
+ * Each FSM is described by an fsm structure and fsm callbacks.
+ */
+typedef struct fsm {
+  int unit;                        /* Interface unit number */
+  u_short protocol;                /* Data Link Layer Protocol field value */
+  int state;                       /* State */
+  int flags;                       /* Contains option bits */
+  u_char id;                       /* Current id */
+  u_char reqid;                    /* Current request id */
+  u_char seen_ack;                 /* Have received valid Ack/Nak/Rej to Req */
+  int timeouttime;                 /* Timeout time in milliseconds */
+  int maxconfreqtransmits;         /* Maximum Configure-Request transmissions */
+  int retransmits;                 /* Number of retransmissions left */
+  int maxtermtransmits;            /* Maximum Terminate-Request transmissions */
+  int nakloops;                    /* Number of nak loops since last ack */
+  int maxnakloops;                 /* Maximum number of nak loops tolerated */
+  struct fsm_callbacks* callbacks; /* Callback routines */
+  char* term_reason;               /* Reason for closing protocol */
+  int term_reason_len;             /* Length of term_reason */
+} fsm;
+
+
+typedef struct fsm_callbacks {
+  void (*resetci)(fsm*);                            /* Reset our Configuration Information */
+  int  (*cilen)(fsm*);                              /* Length of our Configuration Information */
+  void (*addci)(fsm*, u_char*, int*);               /* Add our Configuration Information */
+  int  (*ackci)(fsm*, u_char*, int);                /* ACK our Configuration Information */
+  int  (*nakci)(fsm*, u_char*, int);                /* NAK our Configuration Information */
+  int  (*rejci)(fsm*, u_char*, int);                /* Reject our Configuration Information */
+  int  (*reqci)(fsm*, u_char*, int*, int);          /* Request peer's Configuration Information */
+  void (*up)(fsm*);                                 /* Called when fsm reaches LS_OPENED state */
+  void (*down)(fsm*);                               /* Called when fsm leaves LS_OPENED state */
+  void (*starting)(fsm*);                           /* Called when we want the lower layer */
+  void (*finished)(fsm*);                           /* Called when we don't want the lower layer */
+  void (*protreject)(int);                          /* Called when Protocol-Reject received */
+  void (*retransmit)(fsm*);                         /* Retransmission is necessary */
+  int  (*extcode)(fsm*, int, u_char, u_char*, int); /* Called when unknown code received */
+  char *proto_name;                                 /* String name for protocol (for messages) */
+} fsm_callbacks;
+
+
+/*
+ * Link states.
+ */
+#define LS_INITIAL  0 /* Down, hasn't been opened */
+#define LS_STARTING 1 /* Down, been opened */
+#define LS_CLOSED   2 /* Up, hasn't been opened */
+#define LS_STOPPED  3 /* Open, waiting for down event */
+#define LS_CLOSING  4 /* Terminating the connection, not open */
+#define LS_STOPPING 5 /* Terminating, but open */
+#define LS_REQSENT  6 /* We've sent a Config Request */
+#define LS_ACKRCVD  7 /* We've received a Config Ack */
+#define LS_ACKSENT  8 /* We've sent a Config Ack */
+#define LS_OPENED   9 /* Connection available */
+
+/*
+ * Flags - indicate options controlling FSM operation
+ */
+#define OPT_PASSIVE 1 /* Don't die if we don't get a response */
+#define OPT_RESTART 2 /* Treat 2nd OPEN as DOWN, UP */
+#define OPT_SILENT  4 /* Wait for peer to speak first */
+
+
+/*
+ * Prototypes
+ */
+void fsm_init (fsm*);
+void fsm_lowerup (fsm*);
+void fsm_lowerdown (fsm*);
+void fsm_open (fsm*);
+void fsm_close (fsm*, char*);
+void fsm_input (fsm*, u_char*, int);
+void fsm_protreject (fsm*);
+void fsm_sdata (fsm*, u_char, u_char, u_char*, int);
+
+
+/*
+ * Variables
+ */
+extern int peer_mru[]; /* currently negotiated peer MRU (per unit) */
+
+#endif /* FSM_H */
diff --git a/core/lwip/src/netif/ppp/ipcp.c b/core/lwip/src/netif/ppp/ipcp.c
new file mode 100644
index 00000000..461a600f
--- /dev/null
+++ b/core/lwip/src/netif/ppp/ipcp.c
@@ -0,0 +1,1411 @@
+/** In contrast to pppd 2.3.1, DNS support has been added, proxy-ARP and
+    dial-on-demand has been stripped. */
+/*****************************************************************************
+* ipcp.c - Network PPP IP Control Protocol program file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* portions Copyright (c) 1997 by Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 97-12-08 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
+*   Original.
+*****************************************************************************/
+/*
+ * ipcp.c - PPP IP Control Protocol.
+ *
+ * Copyright (c) 1989 Carnegie Mellon University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Carnegie Mellon University.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#include "lwip/opt.h"
+
+#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
+
+#include "ppp.h"
+#include "pppdebug.h"
+
+#include "auth.h"
+#include "fsm.h"
+#include "vj.h"
+#include "ipcp.h"
+
+#include "lwip/inet.h"
+
+#include <string.h>
+
+/* #define OLD_CI_ADDRS 1 */ /* Support deprecated address negotiation. */
+
+/* global vars */
+ipcp_options ipcp_wantoptions[NUM_PPP];  /* Options that we want to request */
+ipcp_options ipcp_gotoptions[NUM_PPP];   /* Options that peer ack'd */
+ipcp_options ipcp_allowoptions[NUM_PPP]; /* Options we allow peer to request */
+ipcp_options ipcp_hisoptions[NUM_PPP];   /* Options that we ack'd */
+
+/* local vars */
+static int default_route_set[NUM_PPP]; /* Have set up a default route */
+static int cis_received[NUM_PPP];      /* # Conf-Reqs received */
+
+
+/*
+ * Callbacks for fsm code.  (CI = Configuration Information)
+ */
+static void ipcp_resetci (fsm *);                     /* Reset our CI */
+static int  ipcp_cilen (fsm *);                       /* Return length of our CI */
+static void ipcp_addci (fsm *, u_char *, int *);      /* Add our CI */
+static int  ipcp_ackci (fsm *, u_char *, int);        /* Peer ack'd our CI */
+static int  ipcp_nakci (fsm *, u_char *, int);        /* Peer nak'd our CI */
+static int  ipcp_rejci (fsm *, u_char *, int);        /* Peer rej'd our CI */
+static int  ipcp_reqci (fsm *, u_char *, int *, int); /* Rcv CI */
+static void ipcp_up (fsm *);                          /* We're UP */
+static void ipcp_down (fsm *);                        /* We're DOWN */
+#if PPP_ADDITIONAL_CALLBACKS
+static void ipcp_script (fsm *, char *); /* Run an up/down script */
+#endif
+static void ipcp_finished (fsm *);                    /* Don't need lower layer */
+
+
+fsm ipcp_fsm[NUM_PPP]; /* IPCP fsm structure */
+
+
+static fsm_callbacks ipcp_callbacks = { /* IPCP callback routines */
+  ipcp_resetci,  /* Reset our Configuration Information */
+  ipcp_cilen,    /* Length of our Configuration Information */
+  ipcp_addci,    /* Add our Configuration Information */
+  ipcp_ackci,    /* ACK our Configuration Information */
+  ipcp_nakci,    /* NAK our Configuration Information */
+  ipcp_rejci,    /* Reject our Configuration Information */
+  ipcp_reqci,    /* Request peer's Configuration Information */
+  ipcp_up,       /* Called when fsm reaches LS_OPENED state */
+  ipcp_down,     /* Called when fsm leaves LS_OPENED state */
+  NULL,          /* Called when we want the lower layer up */
+  ipcp_finished, /* Called when we want the lower layer down */
+  NULL,          /* Called when Protocol-Reject received */
+  NULL,          /* Retransmission is necessary */
+  NULL,          /* Called to handle protocol-specific codes */
+  "IPCP"         /* String name of protocol */
+};
+
+/*
+ * Protocol entry points from main code.
+ */
+static void ipcp_init (int);
+static void ipcp_open (int);
+static void ipcp_close (int, char *);
+static void ipcp_lowerup (int);
+static void ipcp_lowerdown (int);
+static void ipcp_input (int, u_char *, int);
+static void ipcp_protrej (int);
+
+
+struct protent ipcp_protent = {
+  PPP_IPCP,
+  ipcp_init,
+  ipcp_input,
+  ipcp_protrej,
+  ipcp_lowerup,
+  ipcp_lowerdown,
+  ipcp_open,
+  ipcp_close,
+#if PPP_ADDITIONAL_CALLBACKS
+  ipcp_printpkt,
+  NULL,
+#endif /* PPP_ADDITIONAL_CALLBACKS */
+  1,
+  "IPCP",
+#if PPP_ADDITIONAL_CALLBACKS
+  ip_check_options,
+  NULL,
+  ip_active_pkt
+#endif /* PPP_ADDITIONAL_CALLBACKS */
+};
+
+static void ipcp_clear_addrs (int);
+
+/*
+ * Lengths of configuration options.
+ */
+#define CILEN_VOID     2
+#define CILEN_COMPRESS 4  /* min length for compression protocol opt. */
+#define CILEN_VJ       6  /* length for RFC1332 Van-Jacobson opt. */
+#define CILEN_ADDR     6  /* new-style single address option */
+#define CILEN_ADDRS    10 /* old-style dual address option */
+
+
+#define CODENAME(x) ((x) == CONFACK ? "ACK" : \
+                     (x) == CONFNAK ? "NAK" : "REJ")
+
+
+/*
+ * ipcp_init - Initialize IPCP.
+ */
+static void
+ipcp_init(int unit)
+{
+  fsm           *f = &ipcp_fsm[unit];
+  ipcp_options *wo = &ipcp_wantoptions[unit];
+  ipcp_options *ao = &ipcp_allowoptions[unit];
+
+  f->unit      = unit;
+  f->protocol  = PPP_IPCP;
+  f->callbacks = &ipcp_callbacks;
+  fsm_init(&ipcp_fsm[unit]);
+
+  memset(wo, 0, sizeof(*wo));
+  memset(ao, 0, sizeof(*ao));
+
+  wo->neg_addr      = 1;
+  wo->ouraddr       = 0;
+#if VJ_SUPPORT
+  wo->neg_vj        = 1;
+#else  /* VJ_SUPPORT */
+  wo->neg_vj        = 0;
+#endif /* VJ_SUPPORT */
+  wo->vj_protocol   = IPCP_VJ_COMP;
+  wo->maxslotindex  = MAX_SLOTS - 1;
+  wo->cflag         = 0;
+  wo->default_route = 1;
+
+  ao->neg_addr      = 1;
+#if VJ_SUPPORT
+  ao->neg_vj        = 1;
+#else  /* VJ_SUPPORT */
+  ao->neg_vj        = 0;
+#endif /* VJ_SUPPORT */
+  ao->maxslotindex  = MAX_SLOTS - 1;
+  ao->cflag         = 1;
+  ao->default_route = 1;
+}
+
+
+/*
+ * ipcp_open - IPCP is allowed to come up.
+ */
+static void
+ipcp_open(int unit)
+{
+  fsm_open(&ipcp_fsm[unit]);
+}
+
+
+/*
+ * ipcp_close - Take IPCP down.
+ */
+static void
+ipcp_close(int unit, char *reason)
+{
+  fsm_close(&ipcp_fsm[unit], reason);
+}
+
+
+/*
+ * ipcp_lowerup - The lower layer is up.
+ */
+static void
+ipcp_lowerup(int unit)
+{
+  fsm_lowerup(&ipcp_fsm[unit]);
+}
+
+
+/*
+ * ipcp_lowerdown - The lower layer is down.
+ */
+static void
+ipcp_lowerdown(int unit)
+{
+  fsm_lowerdown(&ipcp_fsm[unit]);
+}
+
+
+/*
+ * ipcp_input - Input IPCP packet.
+ */
+static void
+ipcp_input(int unit, u_char *p, int len)
+{
+  fsm_input(&ipcp_fsm[unit], p, len);
+}
+
+
+/*
+ * ipcp_protrej - A Protocol-Reject was received for IPCP.
+ *
+ * Pretend the lower layer went down, so we shut up.
+ */
+static void
+ipcp_protrej(int unit)
+{
+  fsm_lowerdown(&ipcp_fsm[unit]);
+}
+
+
+/*
+ * ipcp_resetci - Reset our CI.
+ */
+static void
+ipcp_resetci(fsm *f)
+{
+  ipcp_options *wo = &ipcp_wantoptions[f->unit];
+  
+  wo->req_addr = wo->neg_addr && ipcp_allowoptions[f->unit].neg_addr;
+  if (wo->ouraddr == 0) {
+    wo->accept_local = 1;
+  }
+  if (wo->hisaddr == 0) {
+    wo->accept_remote = 1;
+  }
+  /* Request DNS addresses from the peer */
+  wo->req_dns1 = ppp_settings.usepeerdns;
+  wo->req_dns2 = ppp_settings.usepeerdns;
+  ipcp_gotoptions[f->unit] = *wo;
+  cis_received[f->unit] = 0;
+}
+
+
+/*
+ * ipcp_cilen - Return length of our CI.
+ */
+static int
+ipcp_cilen(fsm *f)
+{
+  ipcp_options *go = &ipcp_gotoptions[f->unit];
+  ipcp_options *wo = &ipcp_wantoptions[f->unit];
+  ipcp_options *ho = &ipcp_hisoptions[f->unit];
+
+#define LENCIVJ(neg, old)   (neg ? (old? CILEN_COMPRESS : CILEN_VJ) : 0)
+#define LENCIADDR(neg, old) (neg ? (old? CILEN_ADDRS : CILEN_ADDR) : 0)
+#define LENCIDNS(neg)       (neg ? (CILEN_ADDR) : 0)
+
+  /*
+   * First see if we want to change our options to the old
+   * forms because we have received old forms from the peer.
+   */
+  if (wo->neg_addr && !go->neg_addr && !go->old_addrs) {
+    /* use the old style of address negotiation */
+    go->neg_addr = 1;
+    go->old_addrs = 1;
+  }
+  if (wo->neg_vj && !go->neg_vj && !go->old_vj) {
+    /* try an older style of VJ negotiation */
+    if (cis_received[f->unit] == 0) {
+      /* keep trying the new style until we see some CI from the peer */
+      go->neg_vj = 1;
+    } else {
+      /* use the old style only if the peer did */
+      if (ho->neg_vj && ho->old_vj) {
+        go->neg_vj = 1;
+        go->old_vj = 1;
+        go->vj_protocol = ho->vj_protocol;
+      }
+    }
+  }
+
+  return (LENCIADDR(go->neg_addr, go->old_addrs) +
+          LENCIVJ(go->neg_vj, go->old_vj) +
+          LENCIDNS(go->req_dns1) +
+          LENCIDNS(go->req_dns2));
+}
+
+
+/*
+ * ipcp_addci - Add our desired CIs to a packet.
+ */
+static void
+ipcp_addci(fsm *f, u_char *ucp, int *lenp)
+{
+  ipcp_options *go = &ipcp_gotoptions[f->unit];
+  int len = *lenp;
+
+#define ADDCIVJ(opt, neg, val, old, maxslotindex, cflag) \
+  if (neg) { \
+    int vjlen = old? CILEN_COMPRESS : CILEN_VJ; \
+    if (len >= vjlen) { \
+      PUTCHAR(opt, ucp); \
+      PUTCHAR(vjlen, ucp); \
+      PUTSHORT(val, ucp); \
+      if (!old) { \
+        PUTCHAR(maxslotindex, ucp); \
+        PUTCHAR(cflag, ucp); \
+      } \
+      len -= vjlen; \
+    } else { \
+      neg = 0; \
+    } \
+  }
+
+#define ADDCIADDR(opt, neg, old, val1, val2) \
+  if (neg) { \
+    int addrlen = (old? CILEN_ADDRS: CILEN_ADDR); \
+    if (len >= addrlen) { \
+      u32_t l; \
+      PUTCHAR(opt, ucp); \
+      PUTCHAR(addrlen, ucp); \
+      l = ntohl(val1); \
+      PUTLONG(l, ucp); \
+      if (old) { \
+        l = ntohl(val2); \
+        PUTLONG(l, ucp); \
+      } \
+      len -= addrlen; \
+    } else { \
+      neg = 0; \
+    } \
+  }
+
+#define ADDCIDNS(opt, neg, addr) \
+  if (neg) { \
+    if (len >= CILEN_ADDR) { \
+      u32_t l; \
+      PUTCHAR(opt, ucp); \
+      PUTCHAR(CILEN_ADDR, ucp); \
+      l = ntohl(addr); \
+      PUTLONG(l, ucp); \
+      len -= CILEN_ADDR; \
+    } else { \
+      neg = 0; \
+    } \
+  }
+
+  ADDCIADDR((go->old_addrs? CI_ADDRS: CI_ADDR), go->neg_addr,
+      go->old_addrs, go->ouraddr, go->hisaddr);
+
+  ADDCIVJ(CI_COMPRESSTYPE, go->neg_vj, go->vj_protocol, go->old_vj,
+      go->maxslotindex, go->cflag);
+
+  ADDCIDNS(CI_MS_DNS1, go->req_dns1, go->dnsaddr[0]);
+
+  ADDCIDNS(CI_MS_DNS2, go->req_dns2, go->dnsaddr[1]);
+
+  *lenp -= len;
+}
+
+
+/*
+ * ipcp_ackci - Ack our CIs.
+ *
+ * Returns:
+ *  0 - Ack was bad.
+ *  1 - Ack was good.
+ */
+static int
+ipcp_ackci(fsm *f, u_char *p, int len)
+{
+  ipcp_options *go = &ipcp_gotoptions[f->unit];
+  u_short cilen, citype, cishort;
+  u32_t cilong;
+  u_char cimaxslotindex, cicflag;
+
+  /*
+   * CIs must be in exactly the same order that we sent...
+   * Check packet length and CI length at each step.
+   * If we find any deviations, then this packet is bad.
+   */
+
+#define ACKCIVJ(opt, neg, val, old, maxslotindex, cflag) \
+  if (neg) { \
+    int vjlen = old? CILEN_COMPRESS : CILEN_VJ; \
+    if ((len -= vjlen) < 0) { \
+      goto bad; \
+    } \
+    GETCHAR(citype, p); \
+    GETCHAR(cilen, p); \
+    if (cilen != vjlen || \
+        citype != opt) { \
+      goto bad; \
+    } \
+    GETSHORT(cishort, p); \
+    if (cishort != val) { \
+      goto bad; \
+    } \
+    if (!old) { \
+      GETCHAR(cimaxslotindex, p); \
+      if (cimaxslotindex != maxslotindex) { \
+        goto bad; \
+      } \
+      GETCHAR(cicflag, p); \
+      if (cicflag != cflag) { \
+        goto bad; \
+      } \
+    } \
+  }
+  
+#define ACKCIADDR(opt, neg, old, val1, val2) \
+  if (neg) { \
+    int addrlen = (old? CILEN_ADDRS: CILEN_ADDR); \
+    u32_t l; \
+    if ((len -= addrlen) < 0) { \
+      goto bad; \
+    } \
+    GETCHAR(citype, p); \
+    GETCHAR(cilen, p); \
+    if (cilen != addrlen || \
+        citype != opt) { \
+      goto bad; \
+    } \
+    GETLONG(l, p); \
+    cilong = htonl(l); \
+    if (val1 != cilong) { \
+      goto bad; \
+    } \
+    if (old) { \
+      GETLONG(l, p); \
+      cilong = htonl(l); \
+      if (val2 != cilong) { \
+        goto bad; \
+      } \
+    } \
+  }
+
+#define ACKCIDNS(opt, neg, addr) \
+  if (neg) { \
+    u32_t l; \
+    if ((len -= CILEN_ADDR) < 0) { \
+      goto bad; \
+    } \
+    GETCHAR(citype, p); \
+    GETCHAR(cilen, p); \
+    if (cilen != CILEN_ADDR || \
+        citype != opt) { \
+      goto bad; \
+    } \
+    GETLONG(l, p); \
+    cilong = htonl(l); \
+    if (addr != cilong) { \
+      goto bad; \
+    } \
+  }
+
+  ACKCIADDR((go->old_addrs? CI_ADDRS: CI_ADDR), go->neg_addr,
+        go->old_addrs, go->ouraddr, go->hisaddr);
+
+  ACKCIVJ(CI_COMPRESSTYPE, go->neg_vj, go->vj_protocol, go->old_vj,
+      go->maxslotindex, go->cflag);
+
+  ACKCIDNS(CI_MS_DNS1, go->req_dns1, go->dnsaddr[0]);
+
+  ACKCIDNS(CI_MS_DNS2, go->req_dns2, go->dnsaddr[1]);
+
+  /*
+   * If there are any remaining CIs, then this packet is bad.
+   */
+  if (len != 0) {
+    goto bad;
+  }
+  return (1);
+
+bad:
+  IPCPDEBUG(LOG_INFO, ("ipcp_ackci: received bad Ack!\n"));
+  return (0);
+}
+
+/*
+ * ipcp_nakci - Peer has sent a NAK for some of our CIs.
+ * This should not modify any state if the Nak is bad
+ * or if IPCP is in the LS_OPENED state.
+ *
+ * Returns:
+ *  0 - Nak was bad.
+ *  1 - Nak was good.
+ */
+static int
+ipcp_nakci(fsm *f, u_char *p, int len)
+{
+  ipcp_options *go = &ipcp_gotoptions[f->unit];
+  u_char cimaxslotindex, cicflag;
+  u_char citype, cilen, *next;
+  u_short cishort;
+  u32_t ciaddr1, ciaddr2, l, cidnsaddr;
+  ipcp_options no;    /* options we've seen Naks for */
+  ipcp_options try;    /* options to request next time */
+
+  BZERO(&no, sizeof(no));
+  try = *go;
+
+  /*
+   * Any Nak'd CIs must be in exactly the same order that we sent.
+   * Check packet length and CI length at each step.
+   * If we find any deviations, then this packet is bad.
+   */
+#define NAKCIADDR(opt, neg, old, code) \
+  if (go->neg && \
+      len >= (cilen = (old? CILEN_ADDRS: CILEN_ADDR)) && \
+      p[1] == cilen && \
+      p[0] == opt) { \
+    len -= cilen; \
+    INCPTR(2, p); \
+    GETLONG(l, p); \
+    ciaddr1 = htonl(l); \
+    if (old) { \
+      GETLONG(l, p); \
+      ciaddr2 = htonl(l); \
+      no.old_addrs = 1; \
+    } else { \
+      ciaddr2 = 0; \
+    } \
+    no.neg = 1; \
+    code \
+  }
+
+#define NAKCIVJ(opt, neg, code) \
+  if (go->neg && \
+      ((cilen = p[1]) == CILEN_COMPRESS || cilen == CILEN_VJ) && \
+      len >= cilen && \
+      p[0] == opt) { \
+    len -= cilen; \
+    INCPTR(2, p); \
+    GETSHORT(cishort, p); \
+    no.neg = 1; \
+    code \
+  }
+  
+#define NAKCIDNS(opt, neg, code) \
+  if (go->neg && \
+      ((cilen = p[1]) == CILEN_ADDR) && \
+      len >= cilen && \
+      p[0] == opt) { \
+    len -= cilen; \
+    INCPTR(2, p); \
+    GETLONG(l, p); \
+    cidnsaddr = htonl(l); \
+    no.neg = 1; \
+    code \
+  }
+
+  /*
+   * Accept the peer's idea of {our,his} address, if different
+   * from our idea, only if the accept_{local,remote} flag is set.
+   */
+  NAKCIADDR((go->old_addrs? CI_ADDRS: CI_ADDR), neg_addr, go->old_addrs,
+    if (go->accept_local && ciaddr1) { /* Do we know our address? */
+      try.ouraddr = ciaddr1;
+      IPCPDEBUG(LOG_INFO, ("local IP address %s\n",
+           inet_ntoa(ciaddr1)));
+    }
+    if (go->accept_remote && ciaddr2) { /* Does he know his? */
+      try.hisaddr = ciaddr2;
+      IPCPDEBUG(LOG_INFO, ("remote IP address %s\n",
+           inet_ntoa(ciaddr2)));
+    }
+  );
+
+  /*
+   * Accept the peer's value of maxslotindex provided that it
+   * is less than what we asked for.  Turn off slot-ID compression
+   * if the peer wants.  Send old-style compress-type option if
+   * the peer wants.
+   */
+  NAKCIVJ(CI_COMPRESSTYPE, neg_vj,
+    if (cilen == CILEN_VJ) {
+      GETCHAR(cimaxslotindex, p);
+      GETCHAR(cicflag, p);
+      if (cishort == IPCP_VJ_COMP) {
+        try.old_vj = 0;
+        if (cimaxslotindex < go->maxslotindex) {
+          try.maxslotindex = cimaxslotindex;
+        }
+        if (!cicflag) {
+          try.cflag = 0;
+        }
+      } else {
+        try.neg_vj = 0;
+      }
+    } else {
+      if (cishort == IPCP_VJ_COMP || cishort == IPCP_VJ_COMP_OLD) {
+        try.old_vj = 1;
+        try.vj_protocol = cishort;
+      } else {
+        try.neg_vj = 0;
+      }
+    }
+  );
+
+  NAKCIDNS(CI_MS_DNS1, req_dns1,
+      try.dnsaddr[0] = cidnsaddr;
+        IPCPDEBUG(LOG_INFO, ("primary DNS address %s\n", inet_ntoa(cidnsaddr)));
+      );
+
+  NAKCIDNS(CI_MS_DNS2, req_dns2,
+      try.dnsaddr[1] = cidnsaddr;
+        IPCPDEBUG(LOG_INFO, ("secondary DNS address %s\n", inet_ntoa(cidnsaddr)));
+      );
+
+  /*
+  * There may be remaining CIs, if the peer is requesting negotiation
+  * on an option that we didn't include in our request packet.
+  * If they want to negotiate about IP addresses, we comply.
+  * If they want us to ask for compression, we refuse.
+  */
+  while (len > CILEN_VOID) {
+    GETCHAR(citype, p);
+    GETCHAR(cilen, p);
+    if( (len -= cilen) < 0 ) {
+      goto bad;
+    }
+    next = p + cilen - 2;
+
+    switch (citype) {
+      case CI_COMPRESSTYPE:
+        if (go->neg_vj || no.neg_vj ||
+            (cilen != CILEN_VJ && cilen != CILEN_COMPRESS)) {
+          goto bad;
+        }
+        no.neg_vj = 1;
+        break;
+      case CI_ADDRS:
+        if ((go->neg_addr && go->old_addrs) || no.old_addrs
+            || cilen != CILEN_ADDRS) {
+          goto bad;
+        }
+        try.neg_addr = 1;
+        try.old_addrs = 1;
+        GETLONG(l, p);
+        ciaddr1 = htonl(l);
+        if (ciaddr1 && go->accept_local) {
+          try.ouraddr = ciaddr1;
+        }
+        GETLONG(l, p);
+        ciaddr2 = htonl(l);
+        if (ciaddr2 && go->accept_remote) {
+          try.hisaddr = ciaddr2;
+        }
+        no.old_addrs = 1;
+        break;
+      case CI_ADDR:
+        if (go->neg_addr || no.neg_addr || cilen != CILEN_ADDR) {
+          goto bad;
+        }
+        try.old_addrs = 0;
+        GETLONG(l, p);
+        ciaddr1 = htonl(l);
+        if (ciaddr1 && go->accept_local) {
+          try.ouraddr = ciaddr1;
+        }
+        if (try.ouraddr != 0) {
+          try.neg_addr = 1;
+        }
+        no.neg_addr = 1;
+        break;
+    }
+    p = next;
+  }
+
+  /* If there is still anything left, this packet is bad. */
+  if (len != 0) {
+    goto bad;
+  }
+
+  /*
+   * OK, the Nak is good.  Now we can update state.
+   */
+  if (f->state != LS_OPENED) {
+    *go = try;
+  }
+
+  return 1;
+
+bad:
+  IPCPDEBUG(LOG_INFO, ("ipcp_nakci: received bad Nak!\n"));
+  return 0;
+}
+
+
+/*
+ * ipcp_rejci - Reject some of our CIs.
+ */
+static int
+ipcp_rejci(fsm *f, u_char *p, int len)
+{
+  ipcp_options *go = &ipcp_gotoptions[f->unit];
+  u_char cimaxslotindex, ciflag, cilen;
+  u_short cishort;
+  u32_t cilong;
+  ipcp_options try;    /* options to request next time */
+
+  try = *go;
+  /*
+   * Any Rejected CIs must be in exactly the same order that we sent.
+   * Check packet length and CI length at each step.
+   * If we find any deviations, then this packet is bad.
+   */
+#define REJCIADDR(opt, neg, old, val1, val2) \
+  if (go->neg && \
+      len >= (cilen = old? CILEN_ADDRS: CILEN_ADDR) && \
+      p[1] == cilen && \
+      p[0] == opt) { \
+    u32_t l; \
+    len -= cilen; \
+    INCPTR(2, p); \
+    GETLONG(l, p); \
+    cilong = htonl(l); \
+    /* Check rejected value. */ \
+    if (cilong != val1) { \
+      goto bad; \
+    } \
+    if (old) { \
+      GETLONG(l, p); \
+      cilong = htonl(l); \
+      /* Check rejected value. */ \
+      if (cilong != val2) { \
+        goto bad; \
+      } \
+    } \
+    try.neg = 0; \
+  }
+
+#define REJCIVJ(opt, neg, val, old, maxslot, cflag) \
+  if (go->neg && \
+      p[1] == (old? CILEN_COMPRESS : CILEN_VJ) && \
+      len >= p[1] && \
+      p[0] == opt) { \
+    len -= p[1]; \
+    INCPTR(2, p); \
+    GETSHORT(cishort, p); \
+    /* Check rejected value. */  \
+    if (cishort != val) { \
+      goto bad; \
+    } \
+    if (!old) { \
+      GETCHAR(cimaxslotindex, p); \
+      if (cimaxslotindex != maxslot) { \
+        goto bad; \
+      } \
+      GETCHAR(ciflag, p); \
+      if (ciflag != cflag) { \
+        goto bad; \
+      } \
+    } \
+    try.neg = 0; \
+  }
+
+#define REJCIDNS(opt, neg, dnsaddr) \
+  if (go->neg && \
+      ((cilen = p[1]) == CILEN_ADDR) && \
+      len >= cilen && \
+      p[0] == opt) { \
+    u32_t l; \
+    len -= cilen; \
+    INCPTR(2, p); \
+    GETLONG(l, p); \
+    cilong = htonl(l); \
+    /* Check rejected value. */ \
+    if (cilong != dnsaddr) { \
+      goto bad; \
+    } \
+    try.neg = 0; \
+  }
+
+  REJCIADDR((go->old_addrs? CI_ADDRS: CI_ADDR), neg_addr,
+        go->old_addrs, go->ouraddr, go->hisaddr);
+
+  REJCIVJ(CI_COMPRESSTYPE, neg_vj, go->vj_protocol, go->old_vj,
+      go->maxslotindex, go->cflag);
+
+  REJCIDNS(CI_MS_DNS1, req_dns1, go->dnsaddr[0]);
+
+  REJCIDNS(CI_MS_DNS2, req_dns2, go->dnsaddr[1]);
+
+  /*
+   * If there are any remaining CIs, then this packet is bad.
+   */
+  if (len != 0) {
+    goto bad;
+  }
+  /*
+   * Now we can update state.
+   */
+  if (f->state != LS_OPENED) {
+    *go = try;
+  }
+  return 1;
+
+bad:
+  IPCPDEBUG(LOG_INFO, ("ipcp_rejci: received bad Reject!\n"));
+  return 0;
+}
+
+
+/*
+ * ipcp_reqci - Check the peer's requested CIs and send appropriate response.
+ *
+ * Returns: CONFACK, CONFNAK or CONFREJ and input packet modified
+ * appropriately.  If reject_if_disagree is non-zero, doesn't return
+ * CONFNAK; returns CONFREJ if it can't return CONFACK.
+ */
+static int
+ipcp_reqci(fsm *f, u_char *inp/* Requested CIs */,int *len/* Length of requested CIs */,int reject_if_disagree)
+{
+  ipcp_options *wo = &ipcp_wantoptions[f->unit];
+  ipcp_options *ho = &ipcp_hisoptions[f->unit];
+  ipcp_options *ao = &ipcp_allowoptions[f->unit];
+#ifdef OLD_CI_ADDRS
+  ipcp_options *go = &ipcp_gotoptions[f->unit];
+#endif
+  u_char *cip, *next;     /* Pointer to current and next CIs */
+  u_short cilen, citype;  /* Parsed len, type */
+  u_short cishort;        /* Parsed short value */
+  u32_t tl, ciaddr1;      /* Parsed address values */
+#ifdef OLD_CI_ADDRS
+  u32_t ciaddr2;          /* Parsed address values */
+#endif
+  int rc = CONFACK;       /* Final packet return code */
+  int orc;                /* Individual option return code */
+  u_char *p;              /* Pointer to next char to parse */
+  u_char *ucp = inp;      /* Pointer to current output char */
+  int l = *len;           /* Length left */
+  u_char maxslotindex, cflag;
+  int d;
+
+  cis_received[f->unit] = 1;
+
+  /*
+   * Reset all his options.
+   */
+  BZERO(ho, sizeof(*ho));
+
+  /*
+   * Process all his options.
+   */
+  next = inp;
+  while (l) {
+    orc = CONFACK;       /* Assume success */
+    cip = p = next;      /* Remember begining of CI */
+    if (l < 2 ||         /* Not enough data for CI header or */
+        p[1] < 2 ||      /*  CI length too small or */
+        p[1] > l) {      /*  CI length too big? */
+      IPCPDEBUG(LOG_INFO, ("ipcp_reqci: bad CI length!\n"));
+      orc = CONFREJ;     /* Reject bad CI */
+      cilen = (u_short)l;/* Reject till end of packet */
+      l = 0;             /* Don't loop again */
+      goto endswitch;
+    }
+    GETCHAR(citype, p);  /* Parse CI type */
+    GETCHAR(cilen, p);   /* Parse CI length */
+    l -= cilen;          /* Adjust remaining length */
+    next += cilen;       /* Step to next CI */
+
+    switch (citype) {      /* Check CI type */
+#ifdef OLD_CI_ADDRS /* Need to save space... */
+      case CI_ADDRS:
+        IPCPDEBUG(LOG_INFO, ("ipcp_reqci: received ADDRS\n"));
+        if (!ao->neg_addr ||
+            cilen != CILEN_ADDRS) {  /* Check CI length */
+          orc = CONFREJ;    /* Reject CI */
+          break;
+        }
+
+        /*
+         * If he has no address, or if we both have his address but
+         * disagree about it, then NAK it with our idea.
+         * In particular, if we don't know his address, but he does,
+         * then accept it.
+         */
+        GETLONG(tl, p);    /* Parse source address (his) */
+        ciaddr1 = htonl(tl);
+        IPCPDEBUG(LOG_INFO, ("his addr %s\n", inet_ntoa(ciaddr1)));
+        if (ciaddr1 != wo->hisaddr
+            && (ciaddr1 == 0 || !wo->accept_remote)) {
+          orc = CONFNAK;
+          if (!reject_if_disagree) {
+            DECPTR(sizeof(u32_t), p);
+            tl = ntohl(wo->hisaddr);
+            PUTLONG(tl, p);
+          }
+        } else if (ciaddr1 == 0 && wo->hisaddr == 0) {
+          /*
+           * If neither we nor he knows his address, reject the option.
+           */
+          orc = CONFREJ;
+          wo->req_addr = 0;  /* don't NAK with 0.0.0.0 later */
+          break;
+        }
+
+        /*
+         * If he doesn't know our address, or if we both have our address
+         * but disagree about it, then NAK it with our idea.
+         */
+        GETLONG(tl, p);    /* Parse desination address (ours) */
+        ciaddr2 = htonl(tl);
+        IPCPDEBUG(LOG_INFO, ("our addr %s\n", inet_ntoa(ciaddr2)));
+        if (ciaddr2 != wo->ouraddr) {
+          if (ciaddr2 == 0 || !wo->accept_local) {
+            orc = CONFNAK;
+            if (!reject_if_disagree) {
+              DECPTR(sizeof(u32_t), p);
+              tl = ntohl(wo->ouraddr);
+              PUTLONG(tl, p);
+            }
+          } else {
+            go->ouraddr = ciaddr2;  /* accept peer's idea */
+          }
+        }
+
+        ho->neg_addr = 1;
+        ho->old_addrs = 1;
+        ho->hisaddr = ciaddr1;
+        ho->ouraddr = ciaddr2;
+        break;
+#endif
+
+      case CI_ADDR:
+        if (!ao->neg_addr) {
+          IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Reject ADDR not allowed\n"));
+          orc = CONFREJ;        /* Reject CI */
+          break;
+        } else if (cilen != CILEN_ADDR) {  /* Check CI length */
+          IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Reject ADDR bad len\n"));
+          orc = CONFREJ;        /* Reject CI */
+          break;
+        }
+
+        /*
+         * If he has no address, or if we both have his address but
+         * disagree about it, then NAK it with our idea.
+         * In particular, if we don't know his address, but he does,
+         * then accept it.
+         */
+        GETLONG(tl, p);  /* Parse source address (his) */
+        ciaddr1 = htonl(tl);
+        if (ciaddr1 != wo->hisaddr
+            && (ciaddr1 == 0 || !wo->accept_remote)) {
+          orc = CONFNAK;
+          if (!reject_if_disagree) {
+            DECPTR(sizeof(u32_t), p);
+            tl = ntohl(wo->hisaddr);
+            PUTLONG(tl, p);
+          }
+          IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Nak ADDR %s\n", inet_ntoa(ciaddr1)));
+        } else if (ciaddr1 == 0 && wo->hisaddr == 0) {
+          /*
+           * Don't ACK an address of 0.0.0.0 - reject it instead.
+           */
+          IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Reject ADDR %s\n", inet_ntoa(ciaddr1)));
+          orc = CONFREJ;
+          wo->req_addr = 0;  /* don't NAK with 0.0.0.0 later */
+          break;
+        }
+
+        ho->neg_addr = 1;
+        ho->hisaddr = ciaddr1;
+        IPCPDEBUG(LOG_INFO, ("ipcp_reqci: ADDR %s\n", inet_ntoa(ciaddr1)));
+        break;
+
+      case CI_MS_DNS1:
+      case CI_MS_DNS2:
+        /* Microsoft primary or secondary DNS request */
+        d = citype == CI_MS_DNS2;
+
+        /* If we do not have a DNS address then we cannot send it */
+        if (ao->dnsaddr[d] == 0 ||
+            cilen != CILEN_ADDR) {  /* Check CI length */
+          IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Rejecting DNS%d Request\n", d+1));
+          orc = CONFREJ;        /* Reject CI */
+          break;
+        }
+        GETLONG(tl, p);
+        if (htonl(tl) != ao->dnsaddr[d]) {
+          IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Naking DNS%d Request %s\n",
+                d+1, inet_ntoa(tl)));
+          DECPTR(sizeof(u32_t), p);
+          tl = ntohl(ao->dnsaddr[d]);
+          PUTLONG(tl, p);
+          orc = CONFNAK;
+        }
+        IPCPDEBUG(LOG_INFO, ("ipcp_reqci: received DNS%d Request\n", d+1));
+        break;
+
+      case CI_MS_WINS1:
+      case CI_MS_WINS2:
+        /* Microsoft primary or secondary WINS request */
+        d = citype == CI_MS_WINS2;
+        IPCPDEBUG(LOG_INFO, ("ipcp_reqci: received WINS%d Request\n", d+1));
+
+        /* If we do not have a DNS address then we cannot send it */
+        if (ao->winsaddr[d] == 0 ||
+          cilen != CILEN_ADDR) {  /* Check CI length */
+          orc = CONFREJ;      /* Reject CI */
+          break;
+        }
+        GETLONG(tl, p);
+        if (htonl(tl) != ao->winsaddr[d]) {
+          DECPTR(sizeof(u32_t), p);
+          tl = ntohl(ao->winsaddr[d]);
+          PUTLONG(tl, p);
+          orc = CONFNAK;
+        }
+        break;
+
+      case CI_COMPRESSTYPE:
+        if (!ao->neg_vj) {
+          IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Rejecting COMPRESSTYPE not allowed\n"));
+          orc = CONFREJ;
+          break;
+        } else if (cilen != CILEN_VJ && cilen != CILEN_COMPRESS) {
+          IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Rejecting COMPRESSTYPE len=%d\n", cilen));
+          orc = CONFREJ;
+          break;
+        }
+        GETSHORT(cishort, p);
+
+        if (!(cishort == IPCP_VJ_COMP ||
+            (cishort == IPCP_VJ_COMP_OLD && cilen == CILEN_COMPRESS))) {
+          IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Rejecting COMPRESSTYPE %d\n", cishort));
+          orc = CONFREJ;
+          break;
+        }
+
+        ho->neg_vj = 1;
+        ho->vj_protocol = cishort;
+        if (cilen == CILEN_VJ) {
+          GETCHAR(maxslotindex, p);
+          if (maxslotindex > ao->maxslotindex) { 
+            IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Naking VJ max slot %d\n", maxslotindex));
+            orc = CONFNAK;
+            if (!reject_if_disagree) {
+              DECPTR(1, p);
+              PUTCHAR(ao->maxslotindex, p);
+            }
+          }
+          GETCHAR(cflag, p);
+          if (cflag && !ao->cflag) {
+            IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Naking VJ cflag %d\n", cflag));
+            orc = CONFNAK;
+            if (!reject_if_disagree) {
+              DECPTR(1, p);
+              PUTCHAR(wo->cflag, p);
+            }
+          }
+          ho->maxslotindex = maxslotindex;
+          ho->cflag = cflag;
+        } else {
+          ho->old_vj = 1;
+          ho->maxslotindex = MAX_SLOTS - 1;
+          ho->cflag = 1;
+        }
+        IPCPDEBUG(LOG_INFO, (
+              "ipcp_reqci: received COMPRESSTYPE p=%d old=%d maxslot=%d cflag=%d\n",
+              ho->vj_protocol, ho->old_vj, ho->maxslotindex, ho->cflag));
+        break;
+
+      default:
+        IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Rejecting unknown CI type %d\n", citype));
+        orc = CONFREJ;
+        break;
+    }
+
+endswitch:
+    if (orc == CONFACK &&    /* Good CI */
+        rc != CONFACK) {     /*  but prior CI wasnt? */
+      continue;              /* Don't send this one */
+    }
+
+    if (orc == CONFNAK) {    /* Nak this CI? */
+      if (reject_if_disagree) {  /* Getting fed up with sending NAKs? */
+        IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Rejecting too many naks\n"));
+        orc = CONFREJ;       /* Get tough if so */
+      } else {
+        if (rc == CONFREJ) { /* Rejecting prior CI? */
+          continue;          /* Don't send this one */
+        }
+        if (rc == CONFACK) { /* Ack'd all prior CIs? */
+          rc = CONFNAK;      /* Not anymore... */
+          ucp = inp;         /* Backup */
+        }
+      }
+    }
+
+    if (orc == CONFREJ &&    /* Reject this CI */
+        rc != CONFREJ) {  /*  but no prior ones? */
+      rc = CONFREJ;
+      ucp = inp;        /* Backup */
+    }
+    
+    /* Need to move CI? */
+    if (ucp != cip) {
+      BCOPY(cip, ucp, cilen);  /* Move it */
+    }
+
+    /* Update output pointer */
+    INCPTR(cilen, ucp);
+  }
+
+  /*
+   * If we aren't rejecting this packet, and we want to negotiate
+   * their address, and they didn't send their address, then we
+   * send a NAK with a CI_ADDR option appended.  We assume the
+   * input buffer is long enough that we can append the extra
+   * option safely.
+   */
+  if (rc != CONFREJ && !ho->neg_addr &&
+      wo->req_addr && !reject_if_disagree) {
+    IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Requesting peer address\n"));
+    if (rc == CONFACK) {
+      rc = CONFNAK;
+      ucp = inp;        /* reset pointer */
+      wo->req_addr = 0;    /* don't ask again */
+    }
+    PUTCHAR(CI_ADDR, ucp);
+    PUTCHAR(CILEN_ADDR, ucp);
+    tl = ntohl(wo->hisaddr);
+    PUTLONG(tl, ucp);
+  }
+
+  *len = (int)(ucp - inp);    /* Compute output length */
+  IPCPDEBUG(LOG_INFO, ("ipcp_reqci: returning Configure-%s\n", CODENAME(rc)));
+  return (rc);      /* Return final code */
+}
+
+
+#if 0
+/*
+ * ip_check_options - check that any IP-related options are OK,
+ * and assign appropriate defaults.
+ */
+static void
+ip_check_options(u_long localAddr)
+{
+  ipcp_options *wo = &ipcp_wantoptions[0];
+
+  /*
+   * Load our default IP address but allow the remote host to give us
+   * a new address.
+   */
+  if (wo->ouraddr == 0 && !ppp_settings.disable_defaultip) {
+    wo->accept_local = 1;  /* don't insist on this default value */
+    wo->ouraddr = htonl(localAddr);
+  }
+}
+#endif
+
+
+/*
+ * ipcp_up - IPCP has come UP.
+ *
+ * Configure the IP network interface appropriately and bring it up.
+ */
+static void
+ipcp_up(fsm *f)
+{
+  u32_t mask;
+  ipcp_options *ho = &ipcp_hisoptions[f->unit];
+  ipcp_options *go = &ipcp_gotoptions[f->unit];
+  ipcp_options *wo = &ipcp_wantoptions[f->unit];
+
+  np_up(f->unit, PPP_IP);
+  IPCPDEBUG(LOG_INFO, ("ipcp: up\n"));
+
+  /*
+   * We must have a non-zero IP address for both ends of the link.
+   */
+  if (!ho->neg_addr) {
+    ho->hisaddr = wo->hisaddr;
+  }
+
+  if (ho->hisaddr == 0) {
+    IPCPDEBUG(LOG_ERR, ("Could not determine remote IP address\n"));
+    ipcp_close(f->unit, "Could not determine remote IP address");
+    return;
+  }
+  if (go->ouraddr == 0) {
+    IPCPDEBUG(LOG_ERR, ("Could not determine local IP address\n"));
+    ipcp_close(f->unit, "Could not determine local IP address");
+    return;
+  }
+
+  if (ppp_settings.usepeerdns && (go->dnsaddr[0] || go->dnsaddr[1])) {
+    /*pppGotDNSAddrs(go->dnsaddr[0], go->dnsaddr[1]);*/
+  }
+
+  /*
+   * Check that the peer is allowed to use the IP address it wants.
+   */
+  if (!auth_ip_addr(f->unit, ho->hisaddr)) {
+    IPCPDEBUG(LOG_ERR, ("Peer is not authorized to use remote address %s\n",
+        inet_ntoa(ho->hisaddr)));
+    ipcp_close(f->unit, "Unauthorized remote IP address");
+    return;
+  }
+
+  /* set tcp compression */
+  sifvjcomp(f->unit, ho->neg_vj, ho->cflag, ho->maxslotindex);
+
+  /*
+   * Set IP addresses and (if specified) netmask.
+   */
+  mask = GetMask(go->ouraddr);
+
+  if (!sifaddr(f->unit, go->ouraddr, ho->hisaddr, mask, go->dnsaddr[0], go->dnsaddr[1])) {
+    IPCPDEBUG(LOG_WARNING, ("sifaddr failed\n"));
+    ipcp_close(f->unit, "Interface configuration failed");
+    return;
+  }
+
+  /* bring the interface up for IP */
+  if (!sifup(f->unit)) {
+    IPCPDEBUG(LOG_WARNING, ("sifup failed\n"));
+    ipcp_close(f->unit, "Interface configuration failed");
+    return;
+  }
+
+  sifnpmode(f->unit, PPP_IP, NPMODE_PASS);
+
+  /* assign a default route through the interface if required */
+  if (ipcp_wantoptions[f->unit].default_route) {
+    if (sifdefaultroute(f->unit, go->ouraddr, ho->hisaddr)) {
+      default_route_set[f->unit] = 1;
+    }
+  }
+
+  IPCPDEBUG(LOG_NOTICE, ("local  IP address %s\n", inet_ntoa(go->ouraddr)));
+  IPCPDEBUG(LOG_NOTICE, ("remote IP address %s\n", inet_ntoa(ho->hisaddr)));
+  if (go->dnsaddr[0]) {
+    IPCPDEBUG(LOG_NOTICE, ("primary   DNS address %s\n", inet_ntoa(go->dnsaddr[0])));
+  }
+  if (go->dnsaddr[1]) {
+    IPCPDEBUG(LOG_NOTICE, ("secondary DNS address %s\n", inet_ntoa(go->dnsaddr[1])));
+  }
+}
+
+
+/*
+ * ipcp_down - IPCP has gone DOWN.
+ *
+ * Take the IP network interface down, clear its addresses
+ * and delete routes through it.
+ */
+static void
+ipcp_down(fsm *f)
+{
+  IPCPDEBUG(LOG_INFO, ("ipcp: down\n"));
+  np_down(f->unit, PPP_IP);
+  sifvjcomp(f->unit, 0, 0, 0);
+
+  sifdown(f->unit);
+  ipcp_clear_addrs(f->unit);
+}
+
+
+/*
+ * ipcp_clear_addrs() - clear the interface addresses, routes, etc.
+ */
+static void
+ipcp_clear_addrs(int unit)
+{
+  u32_t ouraddr, hisaddr;
+
+  ouraddr = ipcp_gotoptions[unit].ouraddr;
+  hisaddr = ipcp_hisoptions[unit].hisaddr;
+  if (default_route_set[unit]) {
+    cifdefaultroute(unit, ouraddr, hisaddr);
+    default_route_set[unit] = 0;
+  }
+  cifaddr(unit, ouraddr, hisaddr);
+}
+
+
+/*
+ * ipcp_finished - possibly shut down the lower layers.
+ */
+static void
+ipcp_finished(fsm *f)
+{
+  np_finished(f->unit, PPP_IP);
+}
+
+#if PPP_ADDITIONAL_CALLBACKS
+static int
+ipcp_printpkt(u_char *p, int plen, void (*printer) (void *, char *, ...), void *arg)
+{
+  LWIP_UNUSED_ARG(p);
+  LWIP_UNUSED_ARG(plen);
+  LWIP_UNUSED_ARG(printer);
+  LWIP_UNUSED_ARG(arg);
+  return 0;
+}
+
+/*
+ * ip_active_pkt - see if this IP packet is worth bringing the link up for.
+ * We don't bring the link up for IP fragments or for TCP FIN packets
+ * with no data.
+ */
+#define IP_HDRLEN   20  /* bytes */
+#define IP_OFFMASK  0x1fff
+#define IPPROTO_TCP 6
+#define TCP_HDRLEN  20
+#define TH_FIN      0x01
+
+/*
+ * We use these macros because the IP header may be at an odd address,
+ * and some compilers might use word loads to get th_off or ip_hl.
+ */
+
+#define net_short(x)    (((x)[0] << 8) + (x)[1])
+#define get_iphl(x)     (((unsigned char *)(x))[0] & 0xF)
+#define get_ipoff(x)    net_short((unsigned char *)(x) + 6)
+#define get_ipproto(x)  (((unsigned char *)(x))[9])
+#define get_tcpoff(x)   (((unsigned char *)(x))[12] >> 4)
+#define get_tcpflags(x) (((unsigned char *)(x))[13])
+
+static int
+ip_active_pkt(u_char *pkt, int len)
+{
+  u_char *tcp;
+  int hlen;
+
+  len -= PPP_HDRLEN;
+  pkt += PPP_HDRLEN;
+  if (len < IP_HDRLEN) {
+    return 0;
+  }
+  if ((get_ipoff(pkt) & IP_OFFMASK) != 0) {
+    return 0;
+  }
+  if (get_ipproto(pkt) != IPPROTO_TCP) {
+    return 1;
+  }
+  hlen = get_iphl(pkt) * 4;
+  if (len < hlen + TCP_HDRLEN) {
+    return 0;
+  }
+  tcp = pkt + hlen;
+  if ((get_tcpflags(tcp) & TH_FIN) != 0 && len == hlen + get_tcpoff(tcp) * 4) {
+    return 0;
+  }
+  return 1;
+}
+#endif /* PPP_ADDITIONAL_CALLBACKS */
+
+#endif /* PPP_SUPPORT */
diff --git a/core/lwip/src/netif/ppp/ipcp.h b/core/lwip/src/netif/ppp/ipcp.h
new file mode 100644
index 00000000..de03f460
--- /dev/null
+++ b/core/lwip/src/netif/ppp/ipcp.h
@@ -0,0 +1,106 @@
+/*****************************************************************************
+* ipcp.h -  PPP IP NCP: Internet Protocol Network Control Protocol header file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* portions Copyright (c) 1997 Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 97-12-04 Guy Lancaster <glanca@gesn.com>, Global Election Systems Inc.
+*   Original derived from BSD codes.
+*****************************************************************************/
+/*
+ * ipcp.h - IP Control Protocol definitions.
+ *
+ * Copyright (c) 1989 Carnegie Mellon University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Carnegie Mellon University.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * $Id: ipcp.h,v 1.4 2010/01/18 20:49:43 goldsimon Exp $
+ */
+
+#ifndef IPCP_H
+#define IPCP_H
+
+/*
+ * Options.
+ */
+#define CI_ADDRS            1      /* IP Addresses */
+#define CI_COMPRESSTYPE     2      /* Compression Type */
+#define CI_ADDR             3
+
+#define CI_MS_DNS1          129    /* Primary DNS value */
+#define CI_MS_WINS1         128    /* Primary WINS value */
+#define CI_MS_DNS2          131    /* Secondary DNS value */
+#define CI_MS_WINS2         130    /* Secondary WINS value */
+
+#define IPCP_VJMODE_OLD     1      /* "old" mode (option # = 0x0037) */
+#define IPCP_VJMODE_RFC1172 2      /* "old-rfc"mode (option # = 0x002d) */
+#define IPCP_VJMODE_RFC1332 3      /* "new-rfc"mode (option # = 0x002d, */
+                                   /*  maxslot and slot number compression) */
+
+#define IPCP_VJ_COMP        0x002d /* current value for VJ compression option */
+#define IPCP_VJ_COMP_OLD    0x0037 /* "old" (i.e, broken) value for VJ */
+                                   /* compression option */ 
+
+typedef struct ipcp_options {
+  u_int   neg_addr      : 1; /* Negotiate IP Address? */
+  u_int   old_addrs     : 1; /* Use old (IP-Addresses) option? */
+  u_int   req_addr      : 1; /* Ask peer to send IP address? */
+  u_int   default_route : 1; /* Assign default route through interface? */
+  u_int   proxy_arp     : 1; /* Make proxy ARP entry for peer? */
+  u_int   neg_vj        : 1; /* Van Jacobson Compression? */
+  u_int   old_vj        : 1; /* use old (short) form of VJ option? */
+  u_int   accept_local  : 1; /* accept peer's value for ouraddr */
+  u_int   accept_remote : 1; /* accept peer's value for hisaddr */
+  u_int   req_dns1      : 1; /* Ask peer to send primary DNS address? */
+  u_int   req_dns2      : 1; /* Ask peer to send secondary DNS address? */
+  u_short vj_protocol;       /* protocol value to use in VJ option */
+  u_char  maxslotindex;      /* VJ slots - 1. */
+  u_char  cflag;             /* VJ slot compression flag. */
+  u32_t   ouraddr, hisaddr;  /* Addresses in NETWORK BYTE ORDER */
+  u32_t   dnsaddr[2];        /* Primary and secondary MS DNS entries */
+  u32_t   winsaddr[2];       /* Primary and secondary MS WINS entries */
+} ipcp_options;
+
+extern fsm ipcp_fsm[];
+extern ipcp_options ipcp_wantoptions[];
+extern ipcp_options ipcp_gotoptions[];
+extern ipcp_options ipcp_allowoptions[];
+extern ipcp_options ipcp_hisoptions[];
+
+extern struct protent ipcp_protent;
+
+#endif /* IPCP_H */
diff --git a/core/lwip/src/netif/ppp/lcp.c b/core/lwip/src/netif/ppp/lcp.c
new file mode 100644
index 00000000..21c83ac4
--- /dev/null
+++ b/core/lwip/src/netif/ppp/lcp.c
@@ -0,0 +1,2066 @@
+/*****************************************************************************
+* lcp.c - Network Link Control Protocol program file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* portions Copyright (c) 1997 by Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 97-12-01 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
+*   Original.
+*****************************************************************************/
+
+/*
+ * lcp.c - PPP Link Control Protocol.
+ *
+ * Copyright (c) 1989 Carnegie Mellon University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Carnegie Mellon University.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+ 
+
+#include "lwip/opt.h"
+
+#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
+
+#include "ppp.h"
+#include "pppdebug.h"
+
+#include "fsm.h"
+#include "chap.h"
+#include "magic.h"
+#include "auth.h"
+#include "lcp.h"
+
+#include <string.h>
+
+#if PPPOE_SUPPORT
+#include "netif/ppp_oe.h"
+#else
+#define PPPOE_MAXMTU PPP_MAXMRU
+#endif
+
+#if 0 /* UNUSED */
+/*
+ * LCP-related command-line options.
+ */
+int lcp_echo_interval = 0;  /* Interval between LCP echo-requests */
+int lcp_echo_fails = 0;     /* Tolerance to unanswered echo-requests */
+bool  lax_recv = 0;         /* accept control chars in asyncmap */
+
+static int setescape (char **);
+
+static option_t lcp_option_list[] = {
+    /* LCP options */
+    /* list stripped for simplicity */
+    {NULL}
+};
+#endif /* UNUSED */
+
+/* options */
+LinkPhase lcp_phase[NUM_PPP];          /* Phase of link session (RFC 1661) */
+static u_int lcp_echo_interval      = LCP_ECHOINTERVAL; /* Interval between LCP echo-requests */
+static u_int lcp_echo_fails         = LCP_MAXECHOFAILS; /* Tolerance to unanswered echo-requests */
+
+/* global vars */
+static fsm lcp_fsm[NUM_PPP];                            /* LCP fsm structure (global)*/
+lcp_options lcp_wantoptions[NUM_PPP];  /* Options that we want to request */
+lcp_options lcp_gotoptions[NUM_PPP];   /* Options that peer ack'd */
+lcp_options lcp_allowoptions[NUM_PPP]; /* Options we allow peer to request */
+lcp_options lcp_hisoptions[NUM_PPP];   /* Options that we ack'd */
+ext_accm xmit_accm[NUM_PPP];           /* extended transmit ACCM */
+
+static u32_t lcp_echos_pending      = 0;                /* Number of outstanding echo msgs */
+static u32_t lcp_echo_number        = 0;                /* ID number of next echo frame */
+static u32_t lcp_echo_timer_running = 0;                /* TRUE if a timer is running */
+
+/* @todo: do we really need such a large buffer? The typical 1500 bytes seem too much. */
+static u_char nak_buffer[PPP_MRU]; /* where we construct a nak packet */ 
+
+/*
+ * Callbacks for fsm code.  (CI = Configuration Information)
+ */
+static void lcp_resetci (fsm*);                   /* Reset our CI */
+static int  lcp_cilen (fsm*);                     /* Return length of our CI */
+static void lcp_addci (fsm*, u_char*, int*);      /* Add our CI to pkt */
+static int  lcp_ackci (fsm*, u_char*, int);       /* Peer ack'd our CI */
+static int  lcp_nakci (fsm*, u_char*, int);       /* Peer nak'd our CI */
+static int  lcp_rejci (fsm*, u_char*, int);       /* Peer rej'd our CI */
+static int  lcp_reqci (fsm*, u_char*, int*, int); /* Rcv peer CI */
+static void lcp_up (fsm*);                        /* We're UP */
+static void lcp_down (fsm*);                      /* We're DOWN */
+static void lcp_starting (fsm*);                  /* We need lower layer up */
+static void lcp_finished (fsm*);                  /* We need lower layer down */
+static int  lcp_extcode (fsm*, int, u_char, u_char*, int);
+static void lcp_rprotrej (fsm*, u_char*, int);
+
+/*
+ * routines to send LCP echos to peer
+ */
+
+static void lcp_echo_lowerup (int);
+static void lcp_echo_lowerdown (int);
+static void LcpEchoTimeout (void*);
+static void lcp_received_echo_reply (fsm*, int, u_char*, int);
+static void LcpSendEchoRequest (fsm*);
+static void LcpLinkFailure (fsm*);
+static void LcpEchoCheck (fsm*);
+
+static fsm_callbacks lcp_callbacks = { /* LCP callback routines */
+  lcp_resetci,  /* Reset our Configuration Information */
+  lcp_cilen,    /* Length of our Configuration Information */
+  lcp_addci,    /* Add our Configuration Information */
+  lcp_ackci,    /* ACK our Configuration Information */
+  lcp_nakci,    /* NAK our Configuration Information */
+  lcp_rejci,    /* Reject our Configuration Information */
+  lcp_reqci,    /* Request peer's Configuration Information */
+  lcp_up,       /* Called when fsm reaches LS_OPENED state */
+  lcp_down,     /* Called when fsm leaves LS_OPENED state */
+  lcp_starting, /* Called when we want the lower layer up */
+  lcp_finished, /* Called when we want the lower layer down */
+  NULL,         /* Called when Protocol-Reject received */
+  NULL,         /* Retransmission is necessary */
+  lcp_extcode,  /* Called to handle LCP-specific codes */
+  "LCP"         /* String name of protocol */
+};
+
+/*
+ * Protocol entry points.
+ * Some of these are called directly.
+ */
+
+static void lcp_input (int, u_char *, int);
+static void lcp_protrej (int);
+
+struct protent lcp_protent = {
+    PPP_LCP,
+    lcp_init,
+    lcp_input,
+    lcp_protrej,
+    lcp_lowerup,
+    lcp_lowerdown,
+    lcp_open,
+    lcp_close,
+#if PPP_ADDITIONAL_CALLBACKS
+    lcp_printpkt,
+    NULL,
+#endif /* PPP_ADDITIONAL_CALLBACKS */
+    1,
+    "LCP",
+#if PPP_ADDITIONAL_CALLBACKS
+    NULL,
+    NULL,
+    NULL
+#endif /* PPP_ADDITIONAL_CALLBACKS */
+};
+
+int lcp_loopbackfail = DEFLOOPBACKFAIL;
+
+/*
+ * Length of each type of configuration option (in octets)
+ */
+#define CILEN_VOID  2
+#define CILEN_CHAR  3
+#define CILEN_SHORT 4 /* CILEN_VOID + sizeof(short) */
+#define CILEN_CHAP  5 /* CILEN_VOID + sizeof(short) + 1 */
+#define CILEN_LONG  6 /* CILEN_VOID + sizeof(long) */
+#define CILEN_LQR   8 /* CILEN_VOID + sizeof(short) + sizeof(long) */
+#define CILEN_CBCP  3
+
+#define CODENAME(x)  ((x) == CONFACK ? "ACK" : (x) == CONFNAK ? "NAK" : "REJ")
+
+#if 0 /* UNUSED */
+/*
+ * setescape - add chars to the set we escape on transmission.
+ */
+static int
+setescape(argv)
+    char **argv;
+{
+    int n, ret;
+    char *p, *endp;
+
+    p = *argv;
+    ret = 1;
+    while (*p) {
+      n = strtol(p, &endp, 16);
+      if (p == endp) {
+        option_error("escape parameter contains invalid hex number '%s'", p);
+        return 0;
+      }
+      p = endp;
+      if (n < 0 || n == 0x5E || n > 0xFF) {
+        option_error("can't escape character 0x%x", n);
+        ret = 0;
+      } else
+        xmit_accm[0][n >> 5] |= 1 << (n & 0x1F);
+      while (*p == ',' || *p == ' ')
+        ++p;
+    }
+    return ret;
+}
+#endif /* UNUSED */
+
+/*
+ * lcp_init - Initialize LCP.
+ */
+void
+lcp_init(int unit)
+{
+  fsm         *f  = &lcp_fsm[unit];
+  lcp_options *wo = &lcp_wantoptions[unit];
+  lcp_options *ao = &lcp_allowoptions[unit];
+
+  f->unit      = unit;
+  f->protocol  = PPP_LCP;
+  f->callbacks = &lcp_callbacks;
+
+  fsm_init(f);
+
+  wo->passive           = 0;
+  wo->silent            = 0;
+  wo->restart           = 0;               /* Set to 1 in kernels or multi-line implementations */
+  wo->neg_mru           = 1;
+  wo->mru               = PPP_DEFMRU;
+  wo->neg_asyncmap      = 1;
+  wo->asyncmap          = 0x00000000l;     /* Assume don't need to escape any ctl chars. */
+  wo->neg_chap          = 0;               /* Set to 1 on server */
+  wo->neg_upap          = 0;               /* Set to 1 on server */
+  wo->chap_mdtype       = CHAP_DIGEST_MD5;
+  wo->neg_magicnumber   = 1;
+  wo->neg_pcompression  = 1;
+  wo->neg_accompression = 1;
+  wo->neg_lqr           = 0;               /* no LQR implementation yet */
+  wo->neg_cbcp          = 0;
+
+  ao->neg_mru           = 1;
+  ao->mru               = PPP_MAXMRU;
+  ao->neg_asyncmap      = 1;
+  ao->asyncmap          = 0x00000000l;     /* Assume don't need to escape any ctl chars. */
+  ao->neg_chap          = (CHAP_SUPPORT != 0);
+  ao->chap_mdtype       = CHAP_DIGEST_MD5;
+  ao->neg_upap          = (PAP_SUPPORT != 0);
+  ao->neg_magicnumber   = 1;
+  ao->neg_pcompression  = 1;
+  ao->neg_accompression = 1;
+  ao->neg_lqr           = 0;               /* no LQR implementation yet */
+  ao->neg_cbcp          = (CBCP_SUPPORT != 0);
+
+  /* 
+   * Set transmit escape for the flag and escape characters plus anything
+   * set for the allowable options.
+   */
+  memset(xmit_accm[unit], 0, sizeof(xmit_accm[0]));
+  xmit_accm[unit][15] = 0x60;
+  xmit_accm[unit][0]  = (u_char)((ao->asyncmap        & 0xFF));
+  xmit_accm[unit][1]  = (u_char)((ao->asyncmap >> 8)  & 0xFF);
+  xmit_accm[unit][2]  = (u_char)((ao->asyncmap >> 16) & 0xFF);
+  xmit_accm[unit][3]  = (u_char)((ao->asyncmap >> 24) & 0xFF);
+  LCPDEBUG(LOG_INFO, ("lcp_init: xmit_accm=%X %X %X %X\n",
+        xmit_accm[unit][0],
+        xmit_accm[unit][1],
+        xmit_accm[unit][2],
+        xmit_accm[unit][3]));
+  
+  lcp_phase[unit] = PHASE_INITIALIZE;
+}
+
+
+/*
+ * lcp_open - LCP is allowed to come up.
+ */
+void
+lcp_open(int unit)
+{
+  fsm         *f  = &lcp_fsm[unit];
+  lcp_options *wo = &lcp_wantoptions[unit];
+
+  f->flags = 0;
+  if (wo->passive) {
+    f->flags |= OPT_PASSIVE;
+  }
+  if (wo->silent) {
+    f->flags |= OPT_SILENT;
+  }
+  fsm_open(f);
+
+  lcp_phase[unit] = PHASE_ESTABLISH;
+}
+
+
+/*
+ * lcp_close - Take LCP down.
+ */
+void
+lcp_close(int unit, char *reason)
+{
+  fsm *f = &lcp_fsm[unit];
+
+  if (lcp_phase[unit] != PHASE_DEAD) {
+    lcp_phase[unit] = PHASE_TERMINATE;
+  }
+  if (f->state == LS_STOPPED && f->flags & (OPT_PASSIVE|OPT_SILENT)) {
+    /*
+     * This action is not strictly according to the FSM in RFC1548,
+     * but it does mean that the program terminates if you do an
+     * lcp_close() in passive/silent mode when a connection hasn't
+     * been established.
+     */
+    f->state = LS_CLOSED;
+    lcp_finished(f);
+  } else {
+    fsm_close(f, reason);
+  }
+}
+
+
+/*
+ * lcp_lowerup - The lower layer is up.
+ */
+void
+lcp_lowerup(int unit)
+{
+  lcp_options *wo = &lcp_wantoptions[unit];
+
+  /*
+   * Don't use A/C or protocol compression on transmission,
+   * but accept A/C and protocol compressed packets
+   * if we are going to ask for A/C and protocol compression.
+   */
+  ppp_set_xaccm(unit, &xmit_accm[unit]);
+  ppp_send_config(unit, PPP_MRU, 0xffffffffl, 0, 0);
+  ppp_recv_config(unit, PPP_MRU, 0x00000000l,
+  wo->neg_pcompression, wo->neg_accompression);
+  peer_mru[unit] = PPP_MRU;
+  lcp_allowoptions[unit].asyncmap = (u_long)xmit_accm[unit][0]
+                                 | ((u_long)xmit_accm[unit][1] << 8)
+                                 | ((u_long)xmit_accm[unit][2] << 16)
+                                 | ((u_long)xmit_accm[unit][3] << 24);
+  LCPDEBUG(LOG_INFO, ("lcp_lowerup: asyncmap=%X %X %X %X\n",
+            xmit_accm[unit][3],
+            xmit_accm[unit][2],
+            xmit_accm[unit][1],
+            xmit_accm[unit][0]));
+
+  fsm_lowerup(&lcp_fsm[unit]);
+}
+
+
+/*
+ * lcp_lowerdown - The lower layer is down.
+ */
+void
+lcp_lowerdown(int unit)
+{
+  fsm_lowerdown(&lcp_fsm[unit]);
+}
+
+
+/*
+ * lcp_input - Input LCP packet.
+ */
+static void
+lcp_input(int unit, u_char *p, int len)
+{
+  fsm *f = &lcp_fsm[unit];
+
+  fsm_input(f, p, len);
+}
+
+
+/*
+ * lcp_extcode - Handle a LCP-specific code.
+ */
+static int
+lcp_extcode(fsm *f, int code, u_char id, u_char *inp, int len)
+{
+  u_char *magp;
+
+  switch( code ){
+    case PROTREJ:
+      lcp_rprotrej(f, inp, len);
+      break;
+  
+    case ECHOREQ:
+      if (f->state != LS_OPENED) {
+        break;
+      }
+      LCPDEBUG(LOG_INFO, ("lcp: Echo-Request, Rcvd id %d\n", id));
+      magp = inp;
+      PUTLONG(lcp_gotoptions[f->unit].magicnumber, magp);
+      fsm_sdata(f, ECHOREP, id, inp, len);
+      break;
+
+    case ECHOREP:
+      lcp_received_echo_reply(f, id, inp, len);
+      break;
+
+    case DISCREQ:
+      break;
+
+    default:
+      return 0;
+  }
+  return 1;
+}
+
+
+/*
+ * lcp_rprotrej - Receive an Protocol-Reject.
+ *
+ * Figure out which protocol is rejected and inform it.
+ */
+static void
+lcp_rprotrej(fsm *f, u_char *inp, int len)
+{
+  int i;
+  struct protent *protp;
+  u_short prot;
+
+  if (len < (int)sizeof (u_short)) {
+    LCPDEBUG(LOG_INFO, ("lcp_rprotrej: Rcvd short Protocol-Reject packet!\n"));
+    return;
+  }
+
+  GETSHORT(prot, inp);
+
+  LCPDEBUG(LOG_INFO, ("lcp_rprotrej: Rcvd Protocol-Reject packet for %x!\n", prot));
+
+  /*
+   * Protocol-Reject packets received in any state other than the LCP
+   * LS_OPENED state SHOULD be silently discarded.
+   */
+  if( f->state != LS_OPENED ) {
+    LCPDEBUG(LOG_INFO, ("Protocol-Reject discarded: LCP in state %d\n", f->state));
+    return;
+  }
+
+  /*
+   * Upcall the proper Protocol-Reject routine.
+   */
+  for (i = 0; (protp = ppp_protocols[i]) != NULL; ++i) {
+    if (protp->protocol == prot && protp->enabled_flag) {
+      (*protp->protrej)(f->unit);
+      return;
+    }
+  }
+
+  LCPDEBUG(LOG_WARNING, ("Protocol-Reject for unsupported protocol 0x%x\n", prot));
+}
+
+
+/*
+ * lcp_protrej - A Protocol-Reject was received.
+ */
+static void
+lcp_protrej(int unit)
+{
+  LWIP_UNUSED_ARG(unit);
+  /*
+   * Can't reject LCP!
+   */
+  LCPDEBUG(LOG_WARNING, ("lcp_protrej: Received Protocol-Reject for LCP!\n"));
+  fsm_protreject(&lcp_fsm[unit]);
+}
+
+
+/*
+ * lcp_sprotrej - Send a Protocol-Reject for some protocol.
+ */
+void
+lcp_sprotrej(int unit, u_char *p, int len)
+{
+  /*
+   * Send back the protocol and the information field of the
+   * rejected packet.  We only get here if LCP is in the LS_OPENED state.
+   */
+
+  fsm_sdata(&lcp_fsm[unit], PROTREJ, ++lcp_fsm[unit].id, p, len);
+}
+
+
+/*
+ * lcp_resetci - Reset our CI.
+ */
+static void
+lcp_resetci(fsm *f)
+{
+  lcp_wantoptions[f->unit].magicnumber = magic();
+  lcp_wantoptions[f->unit].numloops = 0;
+  lcp_gotoptions[f->unit] = lcp_wantoptions[f->unit];
+  peer_mru[f->unit] = PPP_MRU;
+  auth_reset(f->unit);
+}
+
+
+/*
+ * lcp_cilen - Return length of our CI.
+ */
+static int
+lcp_cilen(fsm *f)
+{
+  lcp_options *go = &lcp_gotoptions[f->unit];
+
+#define LENCIVOID(neg)  ((neg) ? CILEN_VOID : 0)
+#define LENCICHAP(neg)  ((neg) ? CILEN_CHAP : 0)
+#define LENCISHORT(neg) ((neg) ? CILEN_SHORT : 0)
+#define LENCILONG(neg)  ((neg) ? CILEN_LONG : 0)
+#define LENCILQR(neg)   ((neg) ? CILEN_LQR: 0)
+#define LENCICBCP(neg)  ((neg) ? CILEN_CBCP: 0)
+  /*
+   * NB: we only ask for one of CHAP and UPAP, even if we will
+   * accept either.
+   */
+  return (LENCISHORT(go->neg_mru && go->mru != PPP_DEFMRU) +
+          LENCILONG(go->neg_asyncmap && go->asyncmap != 0xFFFFFFFFl) +
+          LENCICHAP(go->neg_chap) +
+          LENCISHORT(!go->neg_chap && go->neg_upap) +
+          LENCILQR(go->neg_lqr) +
+          LENCICBCP(go->neg_cbcp) +
+          LENCILONG(go->neg_magicnumber) +
+          LENCIVOID(go->neg_pcompression) +
+          LENCIVOID(go->neg_accompression));
+}
+
+
+/*
+ * lcp_addci - Add our desired CIs to a packet.
+ */
+static void
+lcp_addci(fsm *f, u_char *ucp, int *lenp)
+{
+  lcp_options *go = &lcp_gotoptions[f->unit];
+  u_char *start_ucp = ucp;
+
+#define ADDCIVOID(opt, neg) \
+  if (neg) { \
+    LCPDEBUG(LOG_INFO, ("lcp_addci: opt=%d\n", opt)); \
+    PUTCHAR(opt, ucp); \
+    PUTCHAR(CILEN_VOID, ucp); \
+  }
+#define ADDCISHORT(opt, neg, val) \
+  if (neg) { \
+    LCPDEBUG(LOG_INFO, ("lcp_addci: INT opt=%d %X\n", opt, val)); \
+    PUTCHAR(opt, ucp); \
+    PUTCHAR(CILEN_SHORT, ucp); \
+    PUTSHORT(val, ucp); \
+  }
+#define ADDCICHAP(opt, neg, val, digest) \
+  if (neg) { \
+    LCPDEBUG(LOG_INFO, ("lcp_addci: CHAP opt=%d %X\n", opt, val)); \
+    PUTCHAR(opt, ucp); \
+    PUTCHAR(CILEN_CHAP, ucp); \
+    PUTSHORT(val, ucp); \
+    PUTCHAR(digest, ucp); \
+  }
+#define ADDCILONG(opt, neg, val) \
+  if (neg) { \
+    LCPDEBUG(LOG_INFO, ("lcp_addci: L opt=%d %lX\n", opt, val)); \
+    PUTCHAR(opt, ucp); \
+    PUTCHAR(CILEN_LONG, ucp); \
+    PUTLONG(val, ucp); \
+  }
+#define ADDCILQR(opt, neg, val) \
+  if (neg) { \
+    LCPDEBUG(LOG_INFO, ("lcp_addci: LQR opt=%d %lX\n", opt, val)); \
+    PUTCHAR(opt, ucp); \
+    PUTCHAR(CILEN_LQR, ucp); \
+    PUTSHORT(PPP_LQR, ucp); \
+    PUTLONG(val, ucp); \
+  }
+#define ADDCICHAR(opt, neg, val) \
+  if (neg) { \
+    LCPDEBUG(LOG_INFO, ("lcp_addci: CHAR opt=%d %X '%z'\n", opt, val, val)); \
+    PUTCHAR(opt, ucp); \
+    PUTCHAR(CILEN_CHAR, ucp); \
+    PUTCHAR(val, ucp); \
+  }
+
+  ADDCISHORT(CI_MRU, go->neg_mru && go->mru != PPP_DEFMRU, go->mru);
+  ADDCILONG(CI_ASYNCMAP, go->neg_asyncmap && go->asyncmap != 0xFFFFFFFFl, go->asyncmap);
+  ADDCICHAP(CI_AUTHTYPE, go->neg_chap, PPP_CHAP, go->chap_mdtype);
+  ADDCISHORT(CI_AUTHTYPE, !go->neg_chap && go->neg_upap, PPP_PAP);
+  ADDCILQR(CI_QUALITY, go->neg_lqr, go->lqr_period);
+  ADDCICHAR(CI_CALLBACK, go->neg_cbcp, CBCP_OPT);
+  ADDCILONG(CI_MAGICNUMBER, go->neg_magicnumber, go->magicnumber);
+  ADDCIVOID(CI_PCOMPRESSION, go->neg_pcompression);
+  ADDCIVOID(CI_ACCOMPRESSION, go->neg_accompression);
+
+  if (ucp - start_ucp != *lenp) {
+    /* this should never happen, because peer_mtu should be 1500 */
+    LCPDEBUG(LOG_ERR, ("Bug in lcp_addci: wrong length\n"));
+  }
+}
+
+
+/*
+ * lcp_ackci - Ack our CIs.
+ * This should not modify any state if the Ack is bad.
+ *
+ * Returns:
+ *  0 - Ack was bad.
+ *  1 - Ack was good.
+ */
+static int
+lcp_ackci(fsm *f, u_char *p, int len)
+{
+  lcp_options *go = &lcp_gotoptions[f->unit];
+  u_char cilen, citype, cichar;
+  u_short cishort;
+  u32_t cilong;
+
+  /*
+   * CIs must be in exactly the same order that we sent.
+   * Check packet length and CI length at each step.
+   * If we find any deviations, then this packet is bad.
+   */
+#define ACKCIVOID(opt, neg) \
+  if (neg) { \
+    if ((len -= CILEN_VOID) < 0) \
+      goto bad; \
+    GETCHAR(citype, p); \
+    GETCHAR(cilen, p); \
+    if (cilen != CILEN_VOID || citype != opt) \
+      goto bad; \
+  }
+#define ACKCISHORT(opt, neg, val) \
+  if (neg) { \
+    if ((len -= CILEN_SHORT) < 0) \
+      goto bad; \
+    GETCHAR(citype, p); \
+    GETCHAR(cilen, p); \
+    if (cilen != CILEN_SHORT || citype != opt) \
+      goto bad; \
+    GETSHORT(cishort, p); \
+    if (cishort != val) \
+      goto bad; \
+  }
+#define ACKCICHAR(opt, neg, val) \
+  if (neg) { \
+    if ((len -= CILEN_CHAR) < 0) \
+      goto bad; \
+    GETCHAR(citype, p); \
+    GETCHAR(cilen, p); \
+    if (cilen != CILEN_CHAR || citype != opt) \
+      goto bad; \
+    GETCHAR(cichar, p); \
+    if (cichar != val) \
+      goto bad; \
+  }
+#define ACKCICHAP(opt, neg, val, digest) \
+  if (neg) { \
+    if ((len -= CILEN_CHAP) < 0) \
+      goto bad; \
+    GETCHAR(citype, p); \
+    GETCHAR(cilen, p); \
+    if (cilen != CILEN_CHAP || citype != opt) \
+      goto bad; \
+    GETSHORT(cishort, p); \
+    if (cishort != val) \
+      goto bad; \
+    GETCHAR(cichar, p); \
+    if (cichar != digest) \
+      goto bad; \
+  }
+#define ACKCILONG(opt, neg, val) \
+  if (neg) { \
+    if ((len -= CILEN_LONG) < 0) \
+      goto bad; \
+    GETCHAR(citype, p); \
+    GETCHAR(cilen, p); \
+    if (cilen != CILEN_LONG ||  citype != opt) \
+      goto bad; \
+    GETLONG(cilong, p); \
+    if (cilong != val) \
+      goto bad; \
+  }
+#define ACKCILQR(opt, neg, val) \
+  if (neg) { \
+    if ((len -= CILEN_LQR) < 0) \
+      goto bad; \
+    GETCHAR(citype, p); \
+    GETCHAR(cilen, p); \
+    if (cilen != CILEN_LQR || citype != opt) \
+      goto bad; \
+    GETSHORT(cishort, p); \
+    if (cishort != PPP_LQR) \
+      goto bad; \
+    GETLONG(cilong, p); \
+    if (cilong != val) \
+      goto bad; \
+  }
+
+  ACKCISHORT(CI_MRU, go->neg_mru && go->mru != PPP_DEFMRU, go->mru);
+  ACKCILONG(CI_ASYNCMAP, go->neg_asyncmap && go->asyncmap != 0xFFFFFFFFl, go->asyncmap);
+  ACKCICHAP(CI_AUTHTYPE, go->neg_chap, PPP_CHAP, go->chap_mdtype);
+  ACKCISHORT(CI_AUTHTYPE, !go->neg_chap && go->neg_upap, PPP_PAP);
+  ACKCILQR(CI_QUALITY, go->neg_lqr, go->lqr_period);
+  ACKCICHAR(CI_CALLBACK, go->neg_cbcp, CBCP_OPT);
+  ACKCILONG(CI_MAGICNUMBER, go->neg_magicnumber, go->magicnumber);
+  ACKCIVOID(CI_PCOMPRESSION, go->neg_pcompression);
+  ACKCIVOID(CI_ACCOMPRESSION, go->neg_accompression);
+
+  /*
+   * If there are any remaining CIs, then this packet is bad.
+   */
+  if (len != 0) {
+    goto bad;
+  }
+  LCPDEBUG(LOG_INFO, ("lcp_acki: Ack\n"));
+  return (1);
+bad:
+  LCPDEBUG(LOG_WARNING, ("lcp_acki: received bad Ack!\n"));
+  return (0);
+}
+
+
+/*
+ * lcp_nakci - Peer has sent a NAK for some of our CIs.
+ * This should not modify any state if the Nak is bad
+ * or if LCP is in the LS_OPENED state.
+ *
+ * Returns:
+ *  0 - Nak was bad.
+ *  1 - Nak was good.
+ */
+static int
+lcp_nakci(fsm *f, u_char *p, int len)
+{
+  lcp_options *go = &lcp_gotoptions[f->unit];
+  lcp_options *wo = &lcp_wantoptions[f->unit];
+  u_char citype, cichar, *next;
+  u_short cishort;
+  u32_t cilong;
+  lcp_options no;     /* options we've seen Naks for */
+  lcp_options try;    /* options to request next time */
+  int looped_back = 0;
+  int cilen;
+
+  BZERO(&no, sizeof(no));
+  try = *go;
+
+  /*
+   * Any Nak'd CIs must be in exactly the same order that we sent.
+   * Check packet length and CI length at each step.
+   * If we find any deviations, then this packet is bad.
+   */
+#define NAKCIVOID(opt, neg, code) \
+  if (go->neg && \
+      len >= CILEN_VOID && \
+      p[1] == CILEN_VOID && \
+      p[0] == opt) { \
+    len -= CILEN_VOID; \
+    INCPTR(CILEN_VOID, p); \
+    no.neg = 1; \
+    code \
+  }
+#define NAKCICHAP(opt, neg, code) \
+  if (go->neg && \
+      len >= CILEN_CHAP && \
+      p[1] == CILEN_CHAP && \
+      p[0] == opt) { \
+    len -= CILEN_CHAP; \
+    INCPTR(2, p); \
+    GETSHORT(cishort, p); \
+    GETCHAR(cichar, p); \
+    no.neg = 1; \
+    code \
+  }
+#define NAKCICHAR(opt, neg, code) \
+  if (go->neg && \
+      len >= CILEN_CHAR && \
+      p[1] == CILEN_CHAR && \
+      p[0] == opt) { \
+    len -= CILEN_CHAR; \
+    INCPTR(2, p); \
+    GETCHAR(cichar, p); \
+    no.neg = 1; \
+    code \
+  }
+#define NAKCISHORT(opt, neg, code) \
+  if (go->neg && \
+      len >= CILEN_SHORT && \
+      p[1] == CILEN_SHORT && \
+      p[0] == opt) { \
+    len -= CILEN_SHORT; \
+    INCPTR(2, p); \
+    GETSHORT(cishort, p); \
+    no.neg = 1; \
+    code \
+  }
+#define NAKCILONG(opt, neg, code) \
+  if (go->neg && \
+      len >= CILEN_LONG && \
+      p[1] == CILEN_LONG && \
+      p[0] == opt) { \
+    len -= CILEN_LONG; \
+    INCPTR(2, p); \
+    GETLONG(cilong, p); \
+    no.neg = 1; \
+    code \
+  }
+#define NAKCILQR(opt, neg, code) \
+  if (go->neg && \
+      len >= CILEN_LQR && \
+      p[1] == CILEN_LQR && \
+      p[0] == opt) { \
+    len -= CILEN_LQR; \
+    INCPTR(2, p); \
+    GETSHORT(cishort, p); \
+    GETLONG(cilong, p); \
+    no.neg = 1; \
+    code \
+  }
+
+  /*
+   * We don't care if they want to send us smaller packets than
+   * we want.  Therefore, accept any MRU less than what we asked for,
+   * but then ignore the new value when setting the MRU in the kernel.
+   * If they send us a bigger MRU than what we asked, accept it, up to
+   * the limit of the default MRU we'd get if we didn't negotiate.
+   */
+  if (go->neg_mru && go->mru != PPP_DEFMRU) {
+    NAKCISHORT(CI_MRU, neg_mru,
+      if (cishort <= wo->mru || cishort < PPP_DEFMRU) {
+        try.mru = cishort;
+      }
+    );
+  }
+
+  /*
+   * Add any characters they want to our (receive-side) asyncmap.
+   */
+  if (go->neg_asyncmap && go->asyncmap != 0xFFFFFFFFl) {
+    NAKCILONG(CI_ASYNCMAP, neg_asyncmap,
+      try.asyncmap = go->asyncmap | cilong;
+    );
+  }
+
+  /*
+   * If they've nak'd our authentication-protocol, check whether
+   * they are proposing a different protocol, or a different
+   * hash algorithm for CHAP.
+   */
+  if ((go->neg_chap || go->neg_upap)
+      && len >= CILEN_SHORT
+      && p[0] == CI_AUTHTYPE && p[1] >= CILEN_SHORT && p[1] <= len) {
+    cilen = p[1];
+    len -= cilen;
+    no.neg_chap = go->neg_chap;
+    no.neg_upap = go->neg_upap;
+    INCPTR(2, p);
+    GETSHORT(cishort, p);
+    if (cishort == PPP_PAP && cilen == CILEN_SHORT) {
+      /*
+       * If we were asking for CHAP, they obviously don't want to do it.
+       * If we weren't asking for CHAP, then we were asking for PAP,
+       * in which case this Nak is bad.
+       */
+      if (!go->neg_chap) {
+        goto bad;
+      }
+      try.neg_chap = 0;
+    
+    } else if (cishort == PPP_CHAP && cilen == CILEN_CHAP) {
+      GETCHAR(cichar, p);
+      if (go->neg_chap) {
+        /*
+         * We were asking for CHAP/MD5; they must want a different
+         * algorithm.  If they can't do MD5, we'll have to stop
+         * asking for CHAP.
+         */
+        if (cichar != go->chap_mdtype) {
+          try.neg_chap = 0;
+        }
+      } else {
+        /*
+         * Stop asking for PAP if we were asking for it.
+         */
+        try.neg_upap = 0;
+      }
+    
+    } else {
+      /*
+       * We don't recognize what they're suggesting.
+       * Stop asking for what we were asking for.
+       */
+      if (go->neg_chap) {
+        try.neg_chap = 0;
+      } else {
+        try.neg_upap = 0;
+      }
+      p += cilen - CILEN_SHORT;
+    }
+  }
+
+  /*
+   * If they can't cope with our link quality protocol, we'll have
+   * to stop asking for LQR.  We haven't got any other protocol.
+   * If they Nak the reporting period, take their value XXX ?
+   */
+  NAKCILQR(CI_QUALITY, neg_lqr,
+    if (cishort != PPP_LQR) {
+      try.neg_lqr = 0;
+    } else {
+      try.lqr_period = cilong;
+    }
+  );
+
+  /*
+   * Only implementing CBCP...not the rest of the callback options
+   */
+  NAKCICHAR(CI_CALLBACK, neg_cbcp,
+    try.neg_cbcp = 0;
+  );
+
+  /*
+   * Check for a looped-back line.
+   */
+  NAKCILONG(CI_MAGICNUMBER, neg_magicnumber,
+    try.magicnumber = magic();
+    looped_back = 1;
+  );
+
+  /*
+   * Peer shouldn't send Nak for protocol compression or
+   * address/control compression requests; they should send
+   * a Reject instead.  If they send a Nak, treat it as a Reject.
+   */
+  NAKCIVOID(CI_PCOMPRESSION, neg_pcompression,
+    try.neg_pcompression = 0;
+  );
+  NAKCIVOID(CI_ACCOMPRESSION, neg_accompression,
+    try.neg_accompression = 0;
+  );
+
+  /*
+   * There may be remaining CIs, if the peer is requesting negotiation
+   * on an option that we didn't include in our request packet.
+   * If we see an option that we requested, or one we've already seen
+   * in this packet, then this packet is bad.
+   * If we wanted to respond by starting to negotiate on the requested
+   * option(s), we could, but we don't, because except for the
+   * authentication type and quality protocol, if we are not negotiating
+   * an option, it is because we were told not to.
+   * For the authentication type, the Nak from the peer means
+   * `let me authenticate myself with you' which is a bit pointless.
+   * For the quality protocol, the Nak means `ask me to send you quality
+   * reports', but if we didn't ask for them, we don't want them.
+   * An option we don't recognize represents the peer asking to
+   * negotiate some option we don't support, so ignore it.
+   */
+  while (len > CILEN_VOID) {
+    GETCHAR(citype, p);
+    GETCHAR(cilen, p);
+    if (cilen < CILEN_VOID || (len -= cilen) < 0) {
+      goto bad;
+    }
+    next = p + cilen - 2;
+
+    switch (citype) {
+      case CI_MRU:
+        if ((go->neg_mru && go->mru != PPP_DEFMRU)
+            || no.neg_mru || cilen != CILEN_SHORT) {
+          goto bad;
+        }
+        GETSHORT(cishort, p);
+        if (cishort < PPP_DEFMRU) {
+          try.mru = cishort;
+        }
+        break;
+      case CI_ASYNCMAP:
+        if ((go->neg_asyncmap && go->asyncmap != 0xFFFFFFFFl)
+            || no.neg_asyncmap || cilen != CILEN_LONG) {
+          goto bad;
+        }
+        break;
+      case CI_AUTHTYPE:
+        if (go->neg_chap || no.neg_chap || go->neg_upap || no.neg_upap) {
+          goto bad;
+        }
+        break;
+      case CI_MAGICNUMBER:
+        if (go->neg_magicnumber || no.neg_magicnumber ||
+            cilen != CILEN_LONG) {
+          goto bad;
+        }
+        break;
+      case CI_PCOMPRESSION:
+        if (go->neg_pcompression || no.neg_pcompression
+            || cilen != CILEN_VOID) {
+          goto bad;
+        }
+        break;
+      case CI_ACCOMPRESSION:
+        if (go->neg_accompression || no.neg_accompression
+            || cilen != CILEN_VOID) {
+          goto bad;
+        }
+        break;
+      case CI_QUALITY:
+        if (go->neg_lqr || no.neg_lqr || cilen != CILEN_LQR) {
+          goto bad;
+        }
+        break;
+    }
+    p = next;
+  }
+
+  /* If there is still anything left, this packet is bad. */
+  if (len != 0) {
+    goto bad;
+  }
+
+  /*
+  * OK, the Nak is good.  Now we can update state.
+  */
+  if (f->state != LS_OPENED) {
+    if (looped_back) {
+      if (++try.numloops >= lcp_loopbackfail) {
+        LCPDEBUG(LOG_NOTICE, ("Serial line is looped back.\n"));
+        lcp_close(f->unit, "Loopback detected");
+      }
+    } else {
+      try.numloops = 0;
+    }
+    *go = try;
+  }
+
+  return 1;
+
+bad:
+  LCPDEBUG(LOG_WARNING, ("lcp_nakci: received bad Nak!\n"));
+  return 0;
+}
+
+
+/*
+ * lcp_rejci - Peer has Rejected some of our CIs.
+ * This should not modify any state if the Reject is bad
+ * or if LCP is in the LS_OPENED state.
+ *
+ * Returns:
+ *  0 - Reject was bad.
+ *  1 - Reject was good.
+ */
+static int
+lcp_rejci(fsm *f, u_char *p, int len)
+{
+  lcp_options *go = &lcp_gotoptions[f->unit];
+  u_char cichar;
+  u_short cishort;
+  u32_t cilong;
+  lcp_options try; /* options to request next time */
+
+  try = *go;
+
+  /*
+   * Any Rejected CIs must be in exactly the same order that we sent.
+   * Check packet length and CI length at each step.
+   * If we find any deviations, then this packet is bad.
+   */
+#define REJCIVOID(opt, neg) \
+  if (go->neg && \
+      len >= CILEN_VOID && \
+      p[1] == CILEN_VOID && \
+      p[0] == opt) { \
+    len -= CILEN_VOID; \
+    INCPTR(CILEN_VOID, p); \
+    try.neg = 0; \
+    LCPDEBUG(LOG_INFO, ("lcp_rejci: void opt %d rejected\n", opt)); \
+  }
+#define REJCISHORT(opt, neg, val) \
+  if (go->neg && \
+      len >= CILEN_SHORT && \
+      p[1] == CILEN_SHORT && \
+      p[0] == opt) { \
+    len -= CILEN_SHORT; \
+    INCPTR(2, p); \
+    GETSHORT(cishort, p); \
+    /* Check rejected value. */ \
+    if (cishort != val) { \
+      goto bad; \
+    } \
+    try.neg = 0; \
+    LCPDEBUG(LOG_INFO, ("lcp_rejci: short opt %d rejected\n", opt)); \
+  }
+#define REJCICHAP(opt, neg, val, digest) \
+  if (go->neg && \
+      len >= CILEN_CHAP && \
+      p[1] == CILEN_CHAP && \
+      p[0] == opt) { \
+    len -= CILEN_CHAP; \
+    INCPTR(2, p); \
+    GETSHORT(cishort, p); \
+    GETCHAR(cichar, p); \
+    /* Check rejected value. */ \
+    if (cishort != val || cichar != digest) { \
+      goto bad; \
+    } \
+    try.neg = 0; \
+    try.neg_upap = 0; \
+    LCPDEBUG(LOG_INFO, ("lcp_rejci: chap opt %d rejected\n", opt)); \
+  }
+#define REJCILONG(opt, neg, val) \
+  if (go->neg && \
+      len >= CILEN_LONG && \
+      p[1] == CILEN_LONG && \
+      p[0] == opt) { \
+    len -= CILEN_LONG; \
+    INCPTR(2, p); \
+    GETLONG(cilong, p); \
+    /* Check rejected value. */ \
+    if (cilong != val) { \
+      goto bad; \
+    } \
+    try.neg = 0; \
+    LCPDEBUG(LOG_INFO, ("lcp_rejci: long opt %d rejected\n", opt)); \
+  }
+#define REJCILQR(opt, neg, val) \
+  if (go->neg && \
+      len >= CILEN_LQR && \
+      p[1] == CILEN_LQR && \
+      p[0] == opt) { \
+    len -= CILEN_LQR; \
+    INCPTR(2, p); \
+    GETSHORT(cishort, p); \
+    GETLONG(cilong, p); \
+    /* Check rejected value. */ \
+    if (cishort != PPP_LQR || cilong != val) { \
+      goto bad; \
+    } \
+    try.neg = 0; \
+    LCPDEBUG(LOG_INFO, ("lcp_rejci: LQR opt %d rejected\n", opt)); \
+  }
+#define REJCICBCP(opt, neg, val) \
+  if (go->neg && \
+      len >= CILEN_CBCP && \
+      p[1] == CILEN_CBCP && \
+      p[0] == opt) { \
+    len -= CILEN_CBCP; \
+    INCPTR(2, p); \
+    GETCHAR(cichar, p); \
+    /* Check rejected value. */ \
+    if (cichar != val) { \
+      goto bad; \
+    } \
+    try.neg = 0; \
+    LCPDEBUG(LOG_INFO, ("lcp_rejci: Callback opt %d rejected\n", opt)); \
+  }
+  
+  REJCISHORT(CI_MRU, neg_mru, go->mru);
+  REJCILONG(CI_ASYNCMAP, neg_asyncmap, go->asyncmap);
+  REJCICHAP(CI_AUTHTYPE, neg_chap, PPP_CHAP, go->chap_mdtype);
+  if (!go->neg_chap) {
+    REJCISHORT(CI_AUTHTYPE, neg_upap, PPP_PAP);
+  }
+  REJCILQR(CI_QUALITY, neg_lqr, go->lqr_period);
+  REJCICBCP(CI_CALLBACK, neg_cbcp, CBCP_OPT);
+  REJCILONG(CI_MAGICNUMBER, neg_magicnumber, go->magicnumber);
+  REJCIVOID(CI_PCOMPRESSION, neg_pcompression);
+  REJCIVOID(CI_ACCOMPRESSION, neg_accompression);
+  
+  /*
+   * If there are any remaining CIs, then this packet is bad.
+   */
+  if (len != 0) {
+    goto bad;
+  }
+  /*
+   * Now we can update state.
+   */
+  if (f->state != LS_OPENED) {
+    *go = try;
+  }
+  return 1;
+  
+bad:
+  LCPDEBUG(LOG_WARNING, ("lcp_rejci: received bad Reject!\n"));
+  return 0;
+}
+
+
+/*
+ * lcp_reqci - Check the peer's requested CIs and send appropriate response.
+ *
+ * Returns: CONFACK, CONFNAK or CONFREJ and input packet modified
+ * appropriately.  If reject_if_disagree is non-zero, doesn't return
+ * CONFNAK; returns CONFREJ if it can't return CONFACK.
+ */
+static int
+lcp_reqci(fsm *f, 
+          u_char *inp,    /* Requested CIs */
+          int *lenp,      /* Length of requested CIs */
+          int reject_if_disagree)
+{
+  lcp_options *go = &lcp_gotoptions[f->unit];
+  lcp_options *ho = &lcp_hisoptions[f->unit];
+  lcp_options *ao = &lcp_allowoptions[f->unit];
+  u_char *cip, *next;         /* Pointer to current and next CIs */
+  int cilen, citype;          /* Parsed len, type */
+  u_char cichar;              /* Parsed char value */
+  u_short cishort;            /* Parsed short value */
+  u32_t cilong;               /* Parse long value */
+  int rc = CONFACK;           /* Final packet return code */
+  int orc;                    /* Individual option return code */
+  u_char *p;                  /* Pointer to next char to parse */
+  u_char *rejp;               /* Pointer to next char in reject frame */
+  u_char *nakp;               /* Pointer to next char in Nak frame */
+  int l = *lenp;              /* Length left */
+#if TRACELCP > 0
+  char traceBuf[80];
+  size_t traceNdx = 0;
+#endif
+
+  /*
+   * Reset all his options.
+   */
+  BZERO(ho, sizeof(*ho));
+
+  /*
+   * Process all his options.
+   */
+  next = inp;
+  nakp = nak_buffer;
+  rejp = inp;
+  while (l) {
+    orc = CONFACK;      /* Assume success */
+    cip = p = next;     /* Remember begining of CI */
+    if (l < 2 ||        /* Not enough data for CI header or */
+        p[1] < 2 ||     /*  CI length too small or */
+        p[1] > l) {     /*  CI length too big? */
+      LCPDEBUG(LOG_WARNING, ("lcp_reqci: bad CI length!\n"));
+      orc = CONFREJ;    /* Reject bad CI */
+      cilen = l;        /* Reject till end of packet */
+      l = 0;            /* Don't loop again */
+      citype = 0;
+      goto endswitch;
+    }
+    GETCHAR(citype, p); /* Parse CI type */
+    GETCHAR(cilen, p);  /* Parse CI length */
+    l -= cilen;         /* Adjust remaining length */
+    next += cilen;      /* Step to next CI */
+
+    switch (citype) {   /* Check CI type */
+      case CI_MRU:
+        if (!ao->neg_mru) {    /* Allow option? */
+          LCPDEBUG(LOG_INFO, ("lcp_reqci: Reject MRU - not allowed\n"));
+          orc = CONFREJ;    /* Reject CI */
+          break;
+        } else if (cilen != CILEN_SHORT) {  /* Check CI length */
+          LCPDEBUG(LOG_INFO, ("lcp_reqci: Reject MRU - bad length\n"));
+          orc = CONFREJ;    /* Reject CI */
+          break;
+        }
+        GETSHORT(cishort, p);  /* Parse MRU */
+
+        /*
+         * He must be able to receive at least our minimum.
+         * No need to check a maximum.  If he sends a large number,
+         * we'll just ignore it.
+         */
+        if (cishort < PPP_MINMRU) {
+          LCPDEBUG(LOG_INFO, ("lcp_reqci: Nak - MRU too small\n"));
+          orc = CONFNAK;    /* Nak CI */
+          PUTCHAR(CI_MRU, nakp);
+          PUTCHAR(CILEN_SHORT, nakp);
+          PUTSHORT(PPP_MINMRU, nakp);  /* Give him a hint */
+          break;
+        }
+        ho->neg_mru = 1;    /* Remember he sent MRU */
+        ho->mru = cishort;    /* And remember value */
+#if TRACELCP > 0
+        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " MRU %d", cishort);
+        traceNdx = strlen(traceBuf);
+#endif
+        break;
+
+      case CI_ASYNCMAP:
+        if (!ao->neg_asyncmap) {
+          LCPDEBUG(LOG_INFO, ("lcp_reqci: Reject ASYNCMAP not allowed\n"));
+          orc = CONFREJ;
+          break;
+        } else if (cilen != CILEN_LONG) {
+          LCPDEBUG(LOG_INFO, ("lcp_reqci: Reject ASYNCMAP bad length\n"));
+          orc = CONFREJ;
+          break;
+        }
+        GETLONG(cilong, p);
+        
+        /*
+         * Asyncmap must have set at least the bits
+         * which are set in lcp_allowoptions[unit].asyncmap.
+         */
+        if ((ao->asyncmap & ~cilong) != 0) {
+          LCPDEBUG(LOG_INFO, ("lcp_reqci: Nak ASYNCMAP %lX missing %lX\n", 
+                    cilong, ao->asyncmap));
+          orc = CONFNAK;
+          PUTCHAR(CI_ASYNCMAP, nakp);
+          PUTCHAR(CILEN_LONG, nakp);
+          PUTLONG(ao->asyncmap | cilong, nakp);
+          break;
+        }
+        ho->neg_asyncmap = 1;
+        ho->asyncmap = cilong;
+#if TRACELCP > 0
+        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " ASYNCMAP=%lX", cilong);
+        traceNdx = strlen(traceBuf);
+#endif
+        break;
+
+      case CI_AUTHTYPE:
+        if (cilen < CILEN_SHORT) {
+          LCPDEBUG(LOG_INFO, ("lcp_reqci: Reject AUTHTYPE missing arg\n"));
+          orc = CONFREJ;
+          break;
+        } else if (!(ao->neg_upap || ao->neg_chap)) {
+          /*
+           * Reject the option if we're not willing to authenticate.
+           */
+          LCPDEBUG(LOG_INFO, ("lcp_reqci: Reject AUTHTYPE not allowed\n"));
+          orc = CONFREJ;
+          break;
+        }
+        GETSHORT(cishort, p);
+        
+        /*
+         * Authtype must be UPAP or CHAP.
+         *
+         * Note: if both ao->neg_upap and ao->neg_chap are set,
+         * and the peer sends a Configure-Request with two
+         * authenticate-protocol requests, one for CHAP and one
+         * for UPAP, then we will reject the second request.
+         * Whether we end up doing CHAP or UPAP depends then on
+         * the ordering of the CIs in the peer's Configure-Request.
+         */
+        
+        if (cishort == PPP_PAP) {
+          if (ho->neg_chap) {  /* we've already accepted CHAP */
+            LCPDEBUG(LOG_WARNING, ("lcp_reqci: Reject AUTHTYPE PAP already accepted\n"));
+            orc = CONFREJ;
+            break;
+          } else if (cilen != CILEN_SHORT) {
+            LCPDEBUG(LOG_WARNING, ("lcp_reqci: Reject AUTHTYPE PAP bad len\n"));
+            orc = CONFREJ;
+            break;
+          }
+          if (!ao->neg_upap) {  /* we don't want to do PAP */
+            LCPDEBUG(LOG_WARNING, ("lcp_reqci: Nak AUTHTYPE PAP not allowed\n"));
+            orc = CONFNAK;  /* NAK it and suggest CHAP */
+            PUTCHAR(CI_AUTHTYPE, nakp);
+            PUTCHAR(CILEN_CHAP, nakp);
+            PUTSHORT(PPP_CHAP, nakp);
+            PUTCHAR(ao->chap_mdtype, nakp);
+            break;
+          }
+          ho->neg_upap = 1;
+#if TRACELCP > 0
+          snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " PAP (%X)", cishort);
+          traceNdx = strlen(traceBuf);
+#endif
+          break;
+        }
+        if (cishort == PPP_CHAP) {
+          if (ho->neg_upap) {  /* we've already accepted PAP */
+            LCPDEBUG(LOG_WARNING, ("lcp_reqci: Reject AUTHTYPE CHAP accepted PAP\n"));
+            orc = CONFREJ;
+            break;
+          } else if (cilen != CILEN_CHAP) {
+            LCPDEBUG(LOG_WARNING, ("lcp_reqci: Reject AUTHTYPE CHAP bad len\n"));
+            orc = CONFREJ;
+            break;
+          }
+          if (!ao->neg_chap) {  /* we don't want to do CHAP */
+            LCPDEBUG(LOG_WARNING, ("lcp_reqci: Nak AUTHTYPE CHAP not allowed\n"));
+            orc = CONFNAK;  /* NAK it and suggest PAP */
+            PUTCHAR(CI_AUTHTYPE, nakp);
+            PUTCHAR(CILEN_SHORT, nakp);
+            PUTSHORT(PPP_PAP, nakp);
+            break;
+          }
+          GETCHAR(cichar, p);  /* get digest type*/
+          if (cichar != CHAP_DIGEST_MD5
+#if MSCHAP_SUPPORT
+              && cichar != CHAP_MICROSOFT
+#endif
+          ) {
+            LCPDEBUG(LOG_WARNING, ("lcp_reqci: Nak AUTHTYPE CHAP digest=%d\n", (int)cichar));
+            orc = CONFNAK;
+            PUTCHAR(CI_AUTHTYPE, nakp);
+            PUTCHAR(CILEN_CHAP, nakp);
+            PUTSHORT(PPP_CHAP, nakp);
+            PUTCHAR(ao->chap_mdtype, nakp);
+            break;
+          }
+#if TRACELCP > 0
+          snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " CHAP %X,%d", cishort, (int)cichar);
+          traceNdx = strlen(traceBuf);
+#endif
+          ho->chap_mdtype = cichar; /* save md type */
+          ho->neg_chap = 1;
+          break;
+        }
+        
+        /*
+         * We don't recognize the protocol they're asking for.
+         * Nak it with something we're willing to do.
+         * (At this point we know ao->neg_upap || ao->neg_chap.)
+         */
+        orc = CONFNAK;
+        PUTCHAR(CI_AUTHTYPE, nakp);
+        if (ao->neg_chap) {
+          LCPDEBUG(LOG_WARNING, ("lcp_reqci: Nak AUTHTYPE %d req CHAP\n", cishort));
+          PUTCHAR(CILEN_CHAP, nakp);
+          PUTSHORT(PPP_CHAP, nakp);
+          PUTCHAR(ao->chap_mdtype, nakp);
+        } else {
+          LCPDEBUG(LOG_WARNING, ("lcp_reqci: Nak AUTHTYPE %d req PAP\n", cishort));
+          PUTCHAR(CILEN_SHORT, nakp);
+          PUTSHORT(PPP_PAP, nakp);
+        }
+        break;
+      
+      case CI_QUALITY:
+        GETSHORT(cishort, p);
+        GETLONG(cilong, p);
+#if TRACELCP > 0
+        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " QUALITY (%x %x)", cishort, (unsigned int) cilong);
+        traceNdx = strlen(traceBuf);
+#endif
+
+        if (!ao->neg_lqr ||
+            cilen != CILEN_LQR) {
+          orc = CONFREJ;
+          break;
+        }
+        
+        /*
+         * Check the protocol and the reporting period.
+         * XXX When should we Nak this, and what with?
+         */
+        if (cishort != PPP_LQR) {
+          orc = CONFNAK;
+          PUTCHAR(CI_QUALITY, nakp);
+          PUTCHAR(CILEN_LQR, nakp);
+          PUTSHORT(PPP_LQR, nakp);
+          PUTLONG(ao->lqr_period, nakp);
+          break;
+        }
+        break;
+      
+      case CI_MAGICNUMBER:
+        if (!(ao->neg_magicnumber || go->neg_magicnumber) ||
+            cilen != CILEN_LONG) {
+          orc = CONFREJ;
+          break;
+        }
+        GETLONG(cilong, p);
+#if TRACELCP > 0
+        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " MAGICNUMBER (%lX)", cilong);
+        traceNdx = strlen(traceBuf);
+#endif
+
+        /*
+         * He must have a different magic number.
+         */
+        if (go->neg_magicnumber &&
+            cilong == go->magicnumber) {
+          cilong = magic();  /* Don't put magic() inside macro! */
+          orc = CONFNAK;
+          PUTCHAR(CI_MAGICNUMBER, nakp);
+          PUTCHAR(CILEN_LONG, nakp);
+          PUTLONG(cilong, nakp);
+          break;
+        }
+        ho->neg_magicnumber = 1;
+        ho->magicnumber = cilong;
+        break;
+      
+      
+      case CI_PCOMPRESSION:
+#if TRACELCP > 0
+        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " PCOMPRESSION");
+        traceNdx = strlen(traceBuf);
+#endif
+        if (!ao->neg_pcompression ||
+            cilen != CILEN_VOID) {
+          orc = CONFREJ;
+          break;
+        }
+        ho->neg_pcompression = 1;
+        break;
+      
+      case CI_ACCOMPRESSION:
+#if TRACELCP > 0
+        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " ACCOMPRESSION");
+        traceNdx = strlen(traceBuf);
+#endif
+        if (!ao->neg_accompression ||
+            cilen != CILEN_VOID) {
+          orc = CONFREJ;
+          break;
+        }
+        ho->neg_accompression = 1;
+        break;
+      
+      case CI_MRRU:
+#if TRACELCP > 0
+        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " CI_MRRU");
+        traceNdx = strlen(traceBuf);
+#endif
+        orc = CONFREJ;
+        break;
+      
+      case CI_SSNHF:
+#if TRACELCP > 0
+        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " CI_SSNHF");
+        traceNdx = strlen(traceBuf);
+#endif
+        orc = CONFREJ;
+        break;
+      
+      case CI_EPDISC:
+#if TRACELCP > 0
+        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " CI_EPDISC");
+        traceNdx = strlen(traceBuf);
+#endif
+        orc = CONFREJ;
+        break;
+      
+      default:
+#if TRACELCP
+        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " unknown %d", citype);
+        traceNdx = strlen(traceBuf);
+#endif
+        orc = CONFREJ;
+        break;
+    }
+
+  endswitch:
+#if TRACELCP
+    if (traceNdx >= 80 - 32) {
+      LCPDEBUG(LOG_INFO, ("lcp_reqci: rcvd%s\n", traceBuf));
+      traceNdx = 0;
+    }
+#endif
+    if (orc == CONFACK && /* Good CI */
+        rc != CONFACK) {  /*  but prior CI wasnt? */
+      continue;           /* Don't send this one */
+    }
+
+    if (orc == CONFNAK) {     /* Nak this CI? */
+      if (reject_if_disagree  /* Getting fed up with sending NAKs? */
+          && citype != CI_MAGICNUMBER) {
+        orc = CONFREJ;        /* Get tough if so */
+      } else {
+        if (rc == CONFREJ) {  /* Rejecting prior CI? */
+          continue;           /* Don't send this one */
+        }
+        rc = CONFNAK;
+      }
+    }
+    if (orc == CONFREJ) {        /* Reject this CI */
+      rc = CONFREJ;
+      if (cip != rejp) {         /* Need to move rejected CI? */
+        BCOPY(cip, rejp, cilen); /* Move it */
+      }
+      INCPTR(cilen, rejp);       /* Update output pointer */
+    }
+  }
+
+  /*
+   * If we wanted to send additional NAKs (for unsent CIs), the
+   * code would go here.  The extra NAKs would go at *nakp.
+   * At present there are no cases where we want to ask the
+   * peer to negotiate an option.
+   */
+
+  switch (rc) {
+    case CONFACK:
+      *lenp = (int)(next - inp);
+      break;
+    case CONFNAK:
+      /*
+       * Copy the Nak'd options from the nak_buffer to the caller's buffer.
+       */
+      *lenp = (int)(nakp - nak_buffer);
+      BCOPY(nak_buffer, inp, *lenp);
+      break;
+    case CONFREJ:
+      *lenp = (int)(rejp - inp);
+      break;
+  }
+
+#if TRACELCP > 0
+  if (traceNdx > 0) {
+    LCPDEBUG(LOG_INFO, ("lcp_reqci: %s\n", traceBuf));
+  }
+#endif
+  LCPDEBUG(LOG_INFO, ("lcp_reqci: returning CONF%s.\n", CODENAME(rc)));
+  return (rc);      /* Return final code */
+}
+
+
+/*
+ * lcp_up - LCP has come UP.
+ */
+static void
+lcp_up(fsm *f)
+{
+  lcp_options *wo = &lcp_wantoptions[f->unit];
+  lcp_options *ho = &lcp_hisoptions[f->unit];
+  lcp_options *go = &lcp_gotoptions[f->unit];
+  lcp_options *ao = &lcp_allowoptions[f->unit];
+
+  if (!go->neg_magicnumber) {
+    go->magicnumber = 0;
+  }
+  if (!ho->neg_magicnumber) {
+    ho->magicnumber = 0;
+  }
+
+  /*
+   * Set our MTU to the smaller of the MTU we wanted and
+   * the MRU our peer wanted.  If we negotiated an MRU,
+   * set our MRU to the larger of value we wanted and
+   * the value we got in the negotiation.
+   */
+  ppp_send_config(f->unit, LWIP_MIN(ao->mru, (ho->neg_mru? ho->mru: PPP_MRU)),
+                 (ho->neg_asyncmap? ho->asyncmap: 0xffffffffl),
+                  ho->neg_pcompression, ho->neg_accompression);
+  /*
+   * If the asyncmap hasn't been negotiated, we really should
+   * set the receive asyncmap to ffffffff, but we set it to 0
+   * for backwards contemptibility.
+   */
+  ppp_recv_config(f->unit, (go->neg_mru? LWIP_MAX(wo->mru, go->mru): PPP_MRU),
+                 (go->neg_asyncmap? go->asyncmap: 0x00000000),
+                  go->neg_pcompression, go->neg_accompression);
+
+  if (ho->neg_mru) {
+    peer_mru[f->unit] = ho->mru;
+  }
+
+  lcp_echo_lowerup(f->unit); /* Enable echo messages */
+
+  link_established(f->unit); /* The link is up; authenticate now */
+}
+
+
+/*
+ * lcp_down - LCP has gone DOWN.
+ *
+ * Alert other protocols.
+ */
+static void
+lcp_down(fsm *f)
+{
+  lcp_options *go = &lcp_gotoptions[f->unit];
+
+  lcp_echo_lowerdown(f->unit);
+
+  link_down(f->unit);
+
+  ppp_send_config(f->unit, PPP_MRU, 0xffffffffl, 0, 0);
+  ppp_recv_config(f->unit, PPP_MRU,
+                  (go->neg_asyncmap? go->asyncmap: 0x00000000),
+                   go->neg_pcompression, go->neg_accompression);
+  peer_mru[f->unit] = PPP_MRU;
+}
+
+
+/*
+ * lcp_starting - LCP needs the lower layer up.
+ */
+static void
+lcp_starting(fsm *f)
+{
+  link_required(f->unit); /* lwip: currently does nothing */
+}
+
+
+/*
+ * lcp_finished - LCP has finished with the lower layer.
+ */
+static void
+lcp_finished(fsm *f)
+{
+  link_terminated(f->unit); /* we are finished with the link */
+}
+
+
+#if PPP_ADDITIONAL_CALLBACKS
+/*
+ * print_string - print a readable representation of a string using
+ * printer.
+ */
+static void
+print_string( char *p, int len, void (*printer) (void *, char *, ...), void *arg)
+{
+  int c;
+  
+  printer(arg, "\"");
+  for (; len > 0; --len) {
+    c = *p++;
+    if (' ' <= c && c <= '~') {
+        if (c == '\\' || c == '"') {
+          printer(arg, "\\");
+        }
+        printer(arg, "%c", c);
+    } else {
+      switch (c) {
+        case '\n':
+          printer(arg, "\\n");
+          break;
+        case '\r':
+          printer(arg, "\\r");
+          break;
+        case '\t':
+          printer(arg, "\\t");
+          break;
+        default:
+          printer(arg, "\\%.3o", c);
+        }
+    }
+  }
+  printer(arg, "\"");
+}
+
+
+/*
+ * lcp_printpkt - print the contents of an LCP packet.
+ */
+static char *lcp_codenames[] = {
+  "ConfReq", "ConfAck", "ConfNak", "ConfRej",
+  "TermReq", "TermAck", "CodeRej", "ProtRej",
+  "EchoReq", "EchoRep", "DiscReq"
+};
+
+static int
+lcp_printpkt( u_char *p, int plen, void (*printer) (void *, char *, ...), void *arg)
+{
+  int code, id, len, olen;
+  u_char *pstart, *optend;
+  u_short cishort;
+  u32_t cilong;
+
+  if (plen < HEADERLEN) {
+    return 0;
+  }
+  pstart = p;
+  GETCHAR(code, p);
+  GETCHAR(id, p);
+  GETSHORT(len, p);
+  if (len < HEADERLEN || len > plen) {
+    return 0;
+  }
+
+  if (code >= 1 && code <= sizeof(lcp_codenames) / sizeof(char *)) {
+    printer(arg, " %s", lcp_codenames[code-1]);
+  } else {
+    printer(arg, " code=0x%x", code);
+  }
+  printer(arg, " id=0x%x", id);
+  len -= HEADERLEN;
+  switch (code) {
+    case CONFREQ:
+    case CONFACK:
+    case CONFNAK:
+    case CONFREJ:
+      /* print option list */
+      while (len >= 2) {
+        GETCHAR(code, p);
+        GETCHAR(olen, p);
+        p -= 2;
+        if (olen < 2 || olen > len) {
+          break;
+        }
+        printer(arg, " <");
+        len -= olen;
+        optend = p + olen;
+        switch (code) {
+          case CI_MRU:
+            if (olen == CILEN_SHORT) {
+              p += 2;
+              GETSHORT(cishort, p);
+              printer(arg, "mru %d", cishort);
+            }
+            break;
+          case CI_ASYNCMAP:
+            if (olen == CILEN_LONG) {
+              p += 2;
+              GETLONG(cilong, p);
+              printer(arg, "asyncmap 0x%lx", cilong);
+            }
+            break;
+          case CI_AUTHTYPE:
+            if (olen >= CILEN_SHORT) {
+              p += 2;
+              printer(arg, "auth ");
+              GETSHORT(cishort, p);
+              switch (cishort) {
+                case PPP_PAP:
+                  printer(arg, "pap");
+                  break;
+                case PPP_CHAP:
+                  printer(arg, "chap");
+                  break;
+                default:
+                  printer(arg, "0x%x", cishort);
+              }
+            }
+            break;
+          case CI_QUALITY:
+            if (olen >= CILEN_SHORT) {
+              p += 2;
+              printer(arg, "quality ");
+              GETSHORT(cishort, p);
+              switch (cishort) {
+                case PPP_LQR:
+                  printer(arg, "lqr");
+                  break;
+                default:
+                  printer(arg, "0x%x", cishort);
+              }
+            }
+            break;
+          case CI_CALLBACK:
+            if (olen >= CILEN_CHAR) {
+              p += 2;
+              printer(arg, "callback ");
+              GETSHORT(cishort, p);
+              switch (cishort) {
+                case CBCP_OPT:
+                  printer(arg, "CBCP");
+                  break;
+                default:
+                  printer(arg, "0x%x", cishort);
+              }
+            }
+            break;
+          case CI_MAGICNUMBER:
+            if (olen == CILEN_LONG) {
+              p += 2;
+              GETLONG(cilong, p);
+              printer(arg, "magic 0x%x", cilong);
+            }
+            break;
+          case CI_PCOMPRESSION:
+            if (olen == CILEN_VOID) {
+              p += 2;
+              printer(arg, "pcomp");
+            }
+            break;
+          case CI_ACCOMPRESSION:
+            if (olen == CILEN_VOID) {
+              p += 2;
+              printer(arg, "accomp");
+            }
+            break;
+        }
+        while (p < optend) {
+          GETCHAR(code, p);
+          printer(arg, " %.2x", code);
+        }
+        printer(arg, ">");
+      }
+      break;
+    
+    case TERMACK:
+    case TERMREQ:
+      if (len > 0 && *p >= ' ' && *p < 0x7f) {
+        printer(arg, " ");
+        print_string((char*)p, len, printer, arg);
+        p += len;
+        len = 0;
+      }
+      break;
+    
+    case ECHOREQ:
+    case ECHOREP:
+    case DISCREQ:
+      if (len >= 4) {
+        GETLONG(cilong, p);
+        printer(arg, " magic=0x%x", cilong);
+        p += 4;
+        len -= 4;
+      }
+      break;
+  }
+
+  /* print the rest of the bytes in the packet */
+  for (; len > 0; --len) {
+    GETCHAR(code, p);
+    printer(arg, " %.2x", code);
+  }
+
+  return (int)(p - pstart);
+}
+#endif /* PPP_ADDITIONAL_CALLBACKS */
+
+/*
+ * Time to shut down the link because there is nothing out there.
+ */
+static void
+LcpLinkFailure (fsm *f)
+{
+  if (f->state == LS_OPENED) {
+    LCPDEBUG(LOG_INFO, ("No response to %d echo-requests\n", lcp_echos_pending));
+    LCPDEBUG(LOG_NOTICE, ("Serial link appears to be disconnected.\n"));
+    lcp_close(f->unit, "Peer not responding");
+  }
+}
+
+/*
+ * Timer expired for the LCP echo requests from this process.
+ */
+static void
+LcpEchoCheck (fsm *f)
+{
+  LcpSendEchoRequest (f);
+
+  /*
+   * Start the timer for the next interval.
+   */
+  LWIP_ASSERT("lcp_echo_timer_running == 0", lcp_echo_timer_running == 0);
+
+  TIMEOUT (LcpEchoTimeout, f, lcp_echo_interval);
+  lcp_echo_timer_running = 1;
+}
+
+/*
+ * LcpEchoTimeout - Timer expired on the LCP echo
+ */
+static void
+LcpEchoTimeout (void *arg)
+{
+  if (lcp_echo_timer_running != 0) {
+    lcp_echo_timer_running = 0;
+    LcpEchoCheck ((fsm *) arg);
+  }
+}
+
+/*
+ * LcpEchoReply - LCP has received a reply to the echo
+ */
+static void
+lcp_received_echo_reply (fsm *f, int id, u_char *inp, int len)
+{
+  u32_t magic;
+
+  LWIP_UNUSED_ARG(id);
+
+  /* Check the magic number - don't count replies from ourselves. */
+  if (len < 4) {
+    LCPDEBUG(LOG_WARNING, ("lcp: received short Echo-Reply, length %d\n", len));
+    return;
+  }
+  GETLONG(magic, inp);
+  if (lcp_gotoptions[f->unit].neg_magicnumber && magic == lcp_gotoptions[f->unit].magicnumber) {
+    LCPDEBUG(LOG_WARNING, ("appear to have received our own echo-reply!\n"));
+    return;
+  }
+
+  /* Reset the number of outstanding echo frames */
+  lcp_echos_pending = 0;
+}
+
+/*
+ * LcpSendEchoRequest - Send an echo request frame to the peer
+ */
+static void
+LcpSendEchoRequest (fsm *f)
+{
+  u32_t lcp_magic;
+  u_char pkt[4], *pktp;
+
+  /*
+   * Detect the failure of the peer at this point.
+   */
+  if (lcp_echo_fails != 0) {
+    if (lcp_echos_pending >= lcp_echo_fails) {
+      LcpLinkFailure(f);
+      lcp_echos_pending = 0;
+    }
+  }
+
+  /*
+   * Make and send the echo request frame.
+   */
+  if (f->state == LS_OPENED) {
+    lcp_magic = lcp_gotoptions[f->unit].magicnumber;
+    pktp = pkt;
+    PUTLONG(lcp_magic, pktp);
+    fsm_sdata(f, ECHOREQ, (u_char)(lcp_echo_number++ & 0xFF), pkt, (int)(pktp - pkt));
+    ++lcp_echos_pending;
+  }
+}
+
+/*
+ * lcp_echo_lowerup - Start the timer for the LCP frame
+ */
+
+static void
+lcp_echo_lowerup (int unit)
+{
+  fsm *f = &lcp_fsm[unit];
+
+  /* Clear the parameters for generating echo frames */
+  lcp_echos_pending      = 0;
+  lcp_echo_number        = 0;
+  lcp_echo_timer_running = 0;
+
+  /* If a timeout interval is specified then start the timer */
+  if (lcp_echo_interval != 0) {
+    LcpEchoCheck (f);
+  }
+}
+
+/*
+ * lcp_echo_lowerdown - Stop the timer for the LCP frame
+ */
+
+static void
+lcp_echo_lowerdown (int unit)
+{
+  fsm *f = &lcp_fsm[unit];
+
+  if (lcp_echo_timer_running != 0) {
+    UNTIMEOUT (LcpEchoTimeout, f);
+    lcp_echo_timer_running = 0;
+  }
+}
+
+#endif /* PPP_SUPPORT */
diff --git a/core/lwip/src/netif/ppp/lcp.h b/core/lwip/src/netif/ppp/lcp.h
new file mode 100644
index 00000000..b9201eeb
--- /dev/null
+++ b/core/lwip/src/netif/ppp/lcp.h
@@ -0,0 +1,151 @@
+/*****************************************************************************
+* lcp.h - Network Link Control Protocol header file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* portions Copyright (c) 1997 Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 97-11-05 Guy Lancaster <glanca@gesn.com>, Global Election Systems Inc.
+*   Original derived from BSD codes.
+*****************************************************************************/
+/*
+ * lcp.h - Link Control Protocol definitions.
+ *
+ * Copyright (c) 1989 Carnegie Mellon University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Carnegie Mellon University.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * $Id: lcp.h,v 1.4 2010/01/18 20:49:43 goldsimon Exp $
+ */
+
+#ifndef LCP_H
+#define LCP_H
+/*
+ * Options.
+ */
+#define CI_MRU           1  /* Maximum Receive Unit */
+#define CI_ASYNCMAP      2  /* Async Control Character Map */
+#define CI_AUTHTYPE      3  /* Authentication Type */
+#define CI_QUALITY       4  /* Quality Protocol */
+#define CI_MAGICNUMBER   5  /* Magic Number */
+#define CI_PCOMPRESSION  7  /* Protocol Field Compression */
+#define CI_ACCOMPRESSION 8  /* Address/Control Field Compression */
+#define CI_CALLBACK      13 /* callback */
+#define CI_MRRU          17 /* max reconstructed receive unit; multilink */
+#define CI_SSNHF         18 /* short sequence numbers for multilink */
+#define CI_EPDISC        19 /* endpoint discriminator */
+
+/*
+ * LCP-specific packet types (code numbers).
+ */
+#define PROTREJ          8  /* Protocol Reject */
+#define ECHOREQ          9  /* Echo Request */
+#define ECHOREP          10 /* Echo Reply */
+#define DISCREQ          11 /* Discard Request */
+#define CBCP_OPT         6  /* Use callback control protocol */
+
+/*
+ * The state of options is described by an lcp_options structure.
+ */
+typedef struct lcp_options {
+    u_int passive           : 1; /* Don't die if we don't get a response */
+    u_int silent            : 1; /* Wait for the other end to start first */
+    u_int restart           : 1; /* Restart vs. exit after close */
+    u_int neg_mru           : 1; /* Negotiate the MRU? */
+    u_int neg_asyncmap      : 1; /* Negotiate the async map? */
+    u_int neg_upap          : 1; /* Ask for UPAP authentication? */
+    u_int neg_chap          : 1; /* Ask for CHAP authentication? */
+    u_int neg_magicnumber   : 1; /* Ask for magic number? */
+    u_int neg_pcompression  : 1; /* HDLC Protocol Field Compression? */
+    u_int neg_accompression : 1; /* HDLC Address/Control Field Compression? */
+    u_int neg_lqr           : 1; /* Negotiate use of Link Quality Reports */
+    u_int neg_cbcp          : 1; /* Negotiate use of CBCP */
+#ifdef PPP_MULTILINK
+    u_int neg_mrru          : 1; /* Negotiate multilink MRRU */
+    u_int neg_ssnhf         : 1; /* Negotiate short sequence numbers */
+    u_int neg_endpoint      : 1; /* Negotiate endpoint discriminator */
+#endif
+    u_short mru;                 /* Value of MRU */
+#ifdef PPP_MULTILINK
+    u_short mrru;                /* Value of MRRU, and multilink enable */
+#endif
+    u_char chap_mdtype;          /* which MD type (hashing algorithm) */
+    u32_t asyncmap;              /* Value of async map */
+    u32_t magicnumber;
+    int numloops;                /* Number of loops during magic number neg. */
+    u32_t lqr_period;            /* Reporting period for LQR 1/100ths second */
+#ifdef PPP_MULTILINK
+    struct epdisc endpoint;      /* endpoint discriminator */
+#endif
+} lcp_options;
+
+/*
+ * Values for phase from BSD pppd.h based on RFC 1661.
+ */
+typedef enum {
+  PHASE_DEAD = 0,
+  PHASE_INITIALIZE,
+  PHASE_ESTABLISH,
+  PHASE_AUTHENTICATE,
+  PHASE_CALLBACK,
+  PHASE_NETWORK,
+  PHASE_TERMINATE
+} LinkPhase;
+
+
+
+extern LinkPhase lcp_phase[NUM_PPP]; /* Phase of link session (RFC 1661) */
+extern lcp_options lcp_wantoptions[];
+extern lcp_options lcp_gotoptions[];
+extern lcp_options lcp_allowoptions[];
+extern lcp_options lcp_hisoptions[];
+extern ext_accm xmit_accm[];
+
+
+void lcp_init     (int);
+void lcp_open     (int);
+void lcp_close    (int, char *);
+void lcp_lowerup  (int);
+void lcp_lowerdown(int);
+void lcp_sprotrej (int, u_char *, int); /* send protocol reject */
+
+extern struct protent lcp_protent;
+
+/* Default number of times we receive our magic number from the peer
+   before deciding the link is looped-back. */
+#define DEFLOOPBACKFAIL 10
+
+#endif /* LCP_H */
diff --git a/core/lwip/src/netif/ppp/magic.c b/core/lwip/src/netif/ppp/magic.c
new file mode 100644
index 00000000..39013308
--- /dev/null
+++ b/core/lwip/src/netif/ppp/magic.c
@@ -0,0 +1,80 @@
+/*****************************************************************************
+* magic.c - Network Random Number Generator program file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* portions Copyright (c) 1997 by Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 97-12-04 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
+*   Original based on BSD magic.c.
+*****************************************************************************/
+/*
+ * magic.c - PPP Magic Number routines.
+ *
+ * Copyright (c) 1989 Carnegie Mellon University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Carnegie Mellon University.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#include "lwip/opt.h"
+
+#if PPP_SUPPORT
+
+#include "ppp.h"
+#include "randm.h"
+#include "magic.h"
+
+
+/*
+ * magicInit - Initialize the magic number generator.
+ *
+ * Since we use another random number generator that has its own
+ * initialization, we do nothing here.
+ */
+void magicInit()
+{
+  return;
+}
+
+/*
+ * magic - Returns the next magic number.
+ */
+u32_t magic()
+{
+  return avRandom();
+}
+
+#endif /* PPP_SUPPORT */
diff --git a/core/lwip/src/netif/ppp/magic.h b/core/lwip/src/netif/ppp/magic.h
new file mode 100644
index 00000000..eba70d20
--- /dev/null
+++ b/core/lwip/src/netif/ppp/magic.h
@@ -0,0 +1,63 @@
+/*****************************************************************************
+* magic.h - Network Random Number Generator header file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* portions Copyright (c) 1997 Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 97-12-04 Guy Lancaster <glanca@gesn.com>, Global Election Systems Inc.
+*   Original derived from BSD codes.
+*****************************************************************************/
+/*
+ * magic.h - PPP Magic Number definitions.
+ *
+ * Copyright (c) 1989 Carnegie Mellon University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Carnegie Mellon University.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * $Id: magic.h,v 1.3 2010/01/18 20:49:43 goldsimon Exp $
+ */
+
+#ifndef MAGIC_H
+#define MAGIC_H
+
+/* Initialize the magic number generator */
+void  magicInit(void);
+
+/* Returns the next magic number */
+u32_t magic(void);
+
+#endif /* MAGIC_H */
diff --git a/core/lwip/src/netif/ppp/md5.c b/core/lwip/src/netif/ppp/md5.c
new file mode 100644
index 00000000..3cb69e2b
--- /dev/null
+++ b/core/lwip/src/netif/ppp/md5.c
@@ -0,0 +1,320 @@
+/*
+ ***********************************************************************
+ ** md5.c -- the source code for MD5 routines                         **
+ ** RSA Data Security, Inc. MD5 Message-Digest Algorithm              **
+ ** Created: 2/17/90 RLR                                              **
+ ** Revised: 1/91 SRD,AJ,BSK,JT Reference C ver., 7/10 constant corr. **
+ ***********************************************************************
+ */
+
+/*
+ ***********************************************************************
+ ** Copyright (C) 1990, RSA Data Security, Inc. All rights reserved.  **
+ **                                                                   **
+ ** License to copy and use this software is granted provided that    **
+ ** it is identified as the "RSA Data Security, Inc. MD5 Message-     **
+ ** Digest Algorithm" in all material mentioning or referencing this  **
+ ** software or this function.                                        **
+ **                                                                   **
+ ** License is also granted to make and use derivative works          **
+ ** provided that such works are identified as "derived from the RSA  **
+ ** Data Security, Inc. MD5 Message-Digest Algorithm" in all          **
+ ** material mentioning or referencing the derived work.              **
+ **                                                                   **
+ ** RSA Data Security, Inc. makes no representations concerning       **
+ ** either the merchantability of this software or the suitability    **
+ ** of this software for any particular purpose.  It is provided "as  **
+ ** is" without express or implied warranty of any kind.              **
+ **                                                                   **
+ ** These notices must be retained in any copies of any part of this  **
+ ** documentation and/or software.                                    **
+ ***********************************************************************
+ */
+
+#include "lwip/opt.h"
+
+#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
+
+#if CHAP_SUPPORT || MD5_SUPPORT
+
+#include "ppp.h"
+#include "pppdebug.h"
+
+#include "md5.h"
+
+#include <string.h>
+
+/*
+ ***********************************************************************
+ **  Message-digest routines:                                         **
+ **  To form the message digest for a message M                       **
+ **    (1) Initialize a context buffer mdContext using MD5Init        **
+ **    (2) Call MD5Update on mdContext and M                          **
+ **    (3) Call MD5Final on mdContext                                 **
+ **  The message digest is now in mdContext->digest[0...15]           **
+ ***********************************************************************
+ */
+
+/* forward declaration */
+static void Transform (u32_t *buf, u32_t *in);
+
+static unsigned char PADDING[64] = {
+  0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+};
+
+/* F, G, H and I are basic MD5 functions */
+#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
+#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
+#define H(x, y, z) ((x) ^ (y) ^ (z))
+#define I(x, y, z) ((y) ^ ((x) | (~z)))
+
+/* ROTATE_LEFT rotates x left n bits */
+#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
+
+/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4 */
+/* Rotation is separate from addition to prevent recomputation */
+#define FF(a, b, c, d, x, s, ac) \
+  {(a) += F ((b), (c), (d)) + (x) + (u32_t)(ac); \
+   (a) = ROTATE_LEFT ((a), (s)); \
+   (a) += (b); \
+  }
+#define GG(a, b, c, d, x, s, ac) \
+  {(a) += G ((b), (c), (d)) + (x) + (u32_t)(ac); \
+   (a) = ROTATE_LEFT ((a), (s)); \
+   (a) += (b); \
+  }
+#define HH(a, b, c, d, x, s, ac) \
+  {(a) += H ((b), (c), (d)) + (x) + (u32_t)(ac); \
+   (a) = ROTATE_LEFT ((a), (s)); \
+   (a) += (b); \
+  }
+#define II(a, b, c, d, x, s, ac) \
+  {(a) += I ((b), (c), (d)) + (x) + (u32_t)(ac); \
+   (a) = ROTATE_LEFT ((a), (s)); \
+   (a) += (b); \
+  }
+
+#ifdef __STDC__
+#define UL(x) x##UL
+#else
+#ifdef WIN32
+#define UL(x) x##UL
+#else
+#define UL(x) x
+#endif
+#endif
+
+/* The routine MD5Init initializes the message-digest context
+   mdContext. All fields are set to zero.
+ */
+void
+MD5Init (MD5_CTX *mdContext)
+{
+  mdContext->i[0] = mdContext->i[1] = (u32_t)0;
+
+  /* Load magic initialization constants. */
+  mdContext->buf[0] = (u32_t)0x67452301UL;
+  mdContext->buf[1] = (u32_t)0xefcdab89UL;
+  mdContext->buf[2] = (u32_t)0x98badcfeUL;
+  mdContext->buf[3] = (u32_t)0x10325476UL;
+}
+
+/* The routine MD5Update updates the message-digest context to
+   account for the presence of each of the characters inBuf[0..inLen-1]
+   in the message whose digest is being computed.
+ */
+void
+MD5Update(MD5_CTX *mdContext, unsigned char *inBuf, unsigned int inLen)
+{
+  u32_t in[16];
+  int mdi;
+  unsigned int i, ii;
+
+#if 0
+  PPPDEBUG(LOG_INFO, ("MD5Update: %u:%.*H\n", inLen, LWIP_MIN(inLen, 20) * 2, inBuf));
+  PPPDEBUG(LOG_INFO, ("MD5Update: %u:%s\n", inLen, inBuf));
+#endif
+  
+  /* compute number of bytes mod 64 */
+  mdi = (int)((mdContext->i[0] >> 3) & 0x3F);
+
+  /* update number of bits */
+  if ((mdContext->i[0] + ((u32_t)inLen << 3)) < mdContext->i[0]) {
+    mdContext->i[1]++;
+  }
+  mdContext->i[0] += ((u32_t)inLen << 3);
+  mdContext->i[1] += ((u32_t)inLen >> 29);
+
+  while (inLen--) {
+    /* add new character to buffer, increment mdi */
+    mdContext->in[mdi++] = *inBuf++;
+
+    /* transform if necessary */
+    if (mdi == 0x40) {
+      for (i = 0, ii = 0; i < 16; i++, ii += 4) {
+        in[i] = (((u32_t)mdContext->in[ii+3]) << 24) |
+                (((u32_t)mdContext->in[ii+2]) << 16) |
+                (((u32_t)mdContext->in[ii+1]) << 8)  |
+                ((u32_t)mdContext->in[ii]);
+      }
+      Transform (mdContext->buf, in);
+      mdi = 0;
+    }
+  }
+}
+
+/* The routine MD5Final terminates the message-digest computation and
+   ends with the desired message digest in mdContext->digest[0...15].
+ */
+void
+MD5Final (unsigned char hash[], MD5_CTX *mdContext)
+{
+  u32_t in[16];
+  int mdi;
+  unsigned int i, ii;
+  unsigned int padLen;
+
+  /* save number of bits */
+  in[14] = mdContext->i[0];
+  in[15] = mdContext->i[1];
+
+  /* compute number of bytes mod 64 */
+  mdi = (int)((mdContext->i[0] >> 3) & 0x3F);
+
+  /* pad out to 56 mod 64 */
+  padLen = (mdi < 56) ? (56 - mdi) : (120 - mdi);
+  MD5Update (mdContext, PADDING, padLen);
+
+  /* append length in bits and transform */
+  for (i = 0, ii = 0; i < 14; i++, ii += 4) {
+    in[i] = (((u32_t)mdContext->in[ii+3]) << 24) |
+            (((u32_t)mdContext->in[ii+2]) << 16) |
+            (((u32_t)mdContext->in[ii+1]) << 8)  |
+            ((u32_t)mdContext->in[ii]);
+  }
+  Transform (mdContext->buf, in);
+
+  /* store buffer in digest */
+  for (i = 0, ii = 0; i < 4; i++, ii += 4) {
+    mdContext->digest[ii]   = (unsigned char)(mdContext->buf[i] & 0xFF);
+    mdContext->digest[ii+1] =
+      (unsigned char)((mdContext->buf[i] >> 8)  & 0xFF);
+    mdContext->digest[ii+2] =
+      (unsigned char)((mdContext->buf[i] >> 16) & 0xFF);
+    mdContext->digest[ii+3] =
+      (unsigned char)((mdContext->buf[i] >> 24) & 0xFF);
+  }
+  SMEMCPY(hash, mdContext->digest, 16);
+}
+
+/* Basic MD5 step. Transforms buf based on in.
+ */
+static void
+Transform (u32_t *buf, u32_t *in)
+{
+  u32_t a = buf[0], b = buf[1], c = buf[2], d = buf[3];
+
+  /* Round 1 */
+#define S11 7
+#define S12 12
+#define S13 17
+#define S14 22
+  FF ( a, b, c, d, in[ 0], S11, UL(3614090360)); /* 1 */
+  FF ( d, a, b, c, in[ 1], S12, UL(3905402710)); /* 2 */
+  FF ( c, d, a, b, in[ 2], S13, UL( 606105819)); /* 3 */
+  FF ( b, c, d, a, in[ 3], S14, UL(3250441966)); /* 4 */
+  FF ( a, b, c, d, in[ 4], S11, UL(4118548399)); /* 5 */
+  FF ( d, a, b, c, in[ 5], S12, UL(1200080426)); /* 6 */
+  FF ( c, d, a, b, in[ 6], S13, UL(2821735955)); /* 7 */
+  FF ( b, c, d, a, in[ 7], S14, UL(4249261313)); /* 8 */
+  FF ( a, b, c, d, in[ 8], S11, UL(1770035416)); /* 9 */
+  FF ( d, a, b, c, in[ 9], S12, UL(2336552879)); /* 10 */
+  FF ( c, d, a, b, in[10], S13, UL(4294925233)); /* 11 */
+  FF ( b, c, d, a, in[11], S14, UL(2304563134)); /* 12 */
+  FF ( a, b, c, d, in[12], S11, UL(1804603682)); /* 13 */
+  FF ( d, a, b, c, in[13], S12, UL(4254626195)); /* 14 */
+  FF ( c, d, a, b, in[14], S13, UL(2792965006)); /* 15 */
+  FF ( b, c, d, a, in[15], S14, UL(1236535329)); /* 16 */
+
+  /* Round 2 */
+#define S21 5
+#define S22 9
+#define S23 14
+#define S24 20
+  GG ( a, b, c, d, in[ 1], S21, UL(4129170786)); /* 17 */
+  GG ( d, a, b, c, in[ 6], S22, UL(3225465664)); /* 18 */
+  GG ( c, d, a, b, in[11], S23, UL( 643717713)); /* 19 */
+  GG ( b, c, d, a, in[ 0], S24, UL(3921069994)); /* 20 */
+  GG ( a, b, c, d, in[ 5], S21, UL(3593408605)); /* 21 */
+  GG ( d, a, b, c, in[10], S22, UL(  38016083)); /* 22 */
+  GG ( c, d, a, b, in[15], S23, UL(3634488961)); /* 23 */
+  GG ( b, c, d, a, in[ 4], S24, UL(3889429448)); /* 24 */
+  GG ( a, b, c, d, in[ 9], S21, UL( 568446438)); /* 25 */
+  GG ( d, a, b, c, in[14], S22, UL(3275163606)); /* 26 */
+  GG ( c, d, a, b, in[ 3], S23, UL(4107603335)); /* 27 */
+  GG ( b, c, d, a, in[ 8], S24, UL(1163531501)); /* 28 */
+  GG ( a, b, c, d, in[13], S21, UL(2850285829)); /* 29 */
+  GG ( d, a, b, c, in[ 2], S22, UL(4243563512)); /* 30 */
+  GG ( c, d, a, b, in[ 7], S23, UL(1735328473)); /* 31 */
+  GG ( b, c, d, a, in[12], S24, UL(2368359562)); /* 32 */
+
+  /* Round 3 */
+#define S31 4
+#define S32 11
+#define S33 16
+#define S34 23
+  HH ( a, b, c, d, in[ 5], S31, UL(4294588738)); /* 33 */
+  HH ( d, a, b, c, in[ 8], S32, UL(2272392833)); /* 34 */
+  HH ( c, d, a, b, in[11], S33, UL(1839030562)); /* 35 */
+  HH ( b, c, d, a, in[14], S34, UL(4259657740)); /* 36 */
+  HH ( a, b, c, d, in[ 1], S31, UL(2763975236)); /* 37 */
+  HH ( d, a, b, c, in[ 4], S32, UL(1272893353)); /* 38 */
+  HH ( c, d, a, b, in[ 7], S33, UL(4139469664)); /* 39 */
+  HH ( b, c, d, a, in[10], S34, UL(3200236656)); /* 40 */
+  HH ( a, b, c, d, in[13], S31, UL( 681279174)); /* 41 */
+  HH ( d, a, b, c, in[ 0], S32, UL(3936430074)); /* 42 */
+  HH ( c, d, a, b, in[ 3], S33, UL(3572445317)); /* 43 */
+  HH ( b, c, d, a, in[ 6], S34, UL(  76029189)); /* 44 */
+  HH ( a, b, c, d, in[ 9], S31, UL(3654602809)); /* 45 */
+  HH ( d, a, b, c, in[12], S32, UL(3873151461)); /* 46 */
+  HH ( c, d, a, b, in[15], S33, UL( 530742520)); /* 47 */
+  HH ( b, c, d, a, in[ 2], S34, UL(3299628645)); /* 48 */
+
+  /* Round 4 */
+#define S41 6
+#define S42 10
+#define S43 15
+#define S44 21
+  II ( a, b, c, d, in[ 0], S41, UL(4096336452)); /* 49 */
+  II ( d, a, b, c, in[ 7], S42, UL(1126891415)); /* 50 */
+  II ( c, d, a, b, in[14], S43, UL(2878612391)); /* 51 */
+  II ( b, c, d, a, in[ 5], S44, UL(4237533241)); /* 52 */
+  II ( a, b, c, d, in[12], S41, UL(1700485571)); /* 53 */
+  II ( d, a, b, c, in[ 3], S42, UL(2399980690)); /* 54 */
+  II ( c, d, a, b, in[10], S43, UL(4293915773)); /* 55 */
+  II ( b, c, d, a, in[ 1], S44, UL(2240044497)); /* 56 */
+  II ( a, b, c, d, in[ 8], S41, UL(1873313359)); /* 57 */
+  II ( d, a, b, c, in[15], S42, UL(4264355552)); /* 58 */
+  II ( c, d, a, b, in[ 6], S43, UL(2734768916)); /* 59 */
+  II ( b, c, d, a, in[13], S44, UL(1309151649)); /* 60 */
+  II ( a, b, c, d, in[ 4], S41, UL(4149444226)); /* 61 */
+  II ( d, a, b, c, in[11], S42, UL(3174756917)); /* 62 */
+  II ( c, d, a, b, in[ 2], S43, UL( 718787259)); /* 63 */
+  II ( b, c, d, a, in[ 9], S44, UL(3951481745)); /* 64 */
+
+  buf[0] += a;
+  buf[1] += b;
+  buf[2] += c;
+  buf[3] += d;
+}
+
+#endif /* CHAP_SUPPORT || MD5_SUPPORT */
+
+#endif /* PPP_SUPPORT */
diff --git a/core/lwip/src/netif/ppp/md5.h b/core/lwip/src/netif/ppp/md5.h
new file mode 100644
index 00000000..e129533f
--- /dev/null
+++ b/core/lwip/src/netif/ppp/md5.h
@@ -0,0 +1,55 @@
+/*
+ ***********************************************************************
+ ** md5.h -- header file for implementation of MD5                    **
+ ** RSA Data Security, Inc. MD5 Message-Digest Algorithm              **
+ ** Created: 2/17/90 RLR                                              **
+ ** Revised: 12/27/90 SRD,AJ,BSK,JT Reference C version               **
+ ** Revised (for MD5): RLR 4/27/91                                    **
+ **   -- G modified to have y&~z instead of y&z                       **
+ **   -- FF, GG, HH modified to add in last register done             **
+ **   -- Access pattern: round 2 works mod 5, round 3 works mod 3     **
+ **   -- distinct additive constant for each step                     **
+ **   -- round 4 added, working mod 7                                 **
+ ***********************************************************************
+ */
+
+/*
+ ***********************************************************************
+ ** Copyright (C) 1990, RSA Data Security, Inc. All rights reserved.  **
+ **                                                                   **
+ ** License to copy and use this software is granted provided that    **
+ ** it is identified as the "RSA Data Security, Inc. MD5 Message-     **
+ ** Digest Algorithm" in all material mentioning or referencing this  **
+ ** software or this function.                                        **
+ **                                                                   **
+ ** License is also granted to make and use derivative works          **
+ ** provided that such works are identified as "derived from the RSA  **
+ ** Data Security, Inc. MD5 Message-Digest Algorithm" in all          **
+ ** material mentioning or referencing the derived work.              **
+ **                                                                   **
+ ** RSA Data Security, Inc. makes no representations concerning       **
+ ** either the merchantability of this software or the suitability    **
+ ** of this software for any particular purpose.  It is provided "as  **
+ ** is" without express or implied warranty of any kind.              **
+ **                                                                   **
+ ** These notices must be retained in any copies of any part of this  **
+ ** documentation and/or software.                                    **
+ ***********************************************************************
+ */
+
+#ifndef MD5_H
+#define MD5_H
+
+/* Data structure for MD5 (Message-Digest) computation */
+typedef struct {
+  u32_t i[2];               /* number of _bits_ handled mod 2^64 */
+  u32_t buf[4];             /* scratch buffer */
+  unsigned char in[64];     /* input buffer */
+  unsigned char digest[16]; /* actual digest after MD5Final call */
+} MD5_CTX;
+
+void MD5Init  ( MD5_CTX *mdContext);
+void MD5Update( MD5_CTX *mdContext, unsigned char *inBuf, unsigned int inLen);
+void MD5Final ( unsigned char hash[], MD5_CTX *mdContext);
+
+#endif /* MD5_H */
diff --git a/core/lwip/src/netif/ppp/pap.c b/core/lwip/src/netif/ppp/pap.c
new file mode 100644
index 00000000..ac44e646
--- /dev/null
+++ b/core/lwip/src/netif/ppp/pap.c
@@ -0,0 +1,628 @@
+/*****************************************************************************
+* pap.c - Network Password Authentication Protocol program file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* portions Copyright (c) 1997 by Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 97-12-12 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
+*   Original.
+*****************************************************************************/
+/*
+ * upap.c - User/Password Authentication Protocol.
+ *
+ * Copyright (c) 1989 Carnegie Mellon University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Carnegie Mellon University.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#include "lwip/opt.h"
+
+#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
+
+#if PAP_SUPPORT /* don't build if not configured for use in lwipopts.h */
+
+#include "ppp.h"
+#include "pppdebug.h"
+
+#include "auth.h"
+#include "pap.h"
+
+#include <string.h>
+
+#if 0 /* UNUSED */
+static bool hide_password = 1;
+
+/*
+ * Command-line options.
+ */
+static option_t pap_option_list[] = {
+    { "hide-password", o_bool, &hide_password,
+      "Don't output passwords to log", 1 },
+    { "show-password", o_bool, &hide_password,
+      "Show password string in debug log messages", 0 },
+    { "pap-restart", o_int, &upap[0].us_timeouttime,
+      "Set retransmit timeout for PAP" },
+    { "pap-max-authreq", o_int, &upap[0].us_maxtransmits,
+      "Set max number of transmissions for auth-reqs" },
+    { "pap-timeout", o_int, &upap[0].us_reqtimeout,
+      "Set time limit for peer PAP authentication" },
+    { NULL }
+};
+#endif
+
+/*
+ * Protocol entry points.
+ */
+static void upap_init      (int);
+static void upap_lowerup   (int);
+static void upap_lowerdown (int);
+static void upap_input     (int, u_char *, int);
+static void upap_protrej   (int);
+#if PPP_ADDITIONAL_CALLBACKS
+static int  upap_printpkt (u_char *, int, void (*)(void *, char *, ...), void *);
+#endif /* PPP_ADDITIONAL_CALLBACKS */
+
+struct protent pap_protent = {
+  PPP_PAP,
+  upap_init,
+  upap_input,
+  upap_protrej,
+  upap_lowerup,
+  upap_lowerdown,
+  NULL,
+  NULL,
+#if PPP_ADDITIONAL_CALLBACKS
+  upap_printpkt,
+  NULL,
+#endif /* PPP_ADDITIONAL_CALLBACKS */
+  1,
+  "PAP",
+#if PPP_ADDITIONAL_CALLBACKS
+  NULL,
+  NULL,
+  NULL
+#endif /* PPP_ADDITIONAL_CALLBACKS */
+};
+
+upap_state upap[NUM_PPP]; /* UPAP state; one for each unit */
+
+static void upap_timeout   (void *);
+static void upap_reqtimeout(void *);
+static void upap_rauthreq  (upap_state *, u_char *, u_char, int);
+static void upap_rauthack  (upap_state *, u_char *, int, int);
+static void upap_rauthnak  (upap_state *, u_char *, int, int);
+static void upap_sauthreq  (upap_state *);
+static void upap_sresp     (upap_state *, u_char, u_char, char *, int);
+
+
+/*
+ * upap_init - Initialize a UPAP unit.
+ */
+static void
+upap_init(int unit)
+{
+  upap_state *u = &upap[unit];
+
+  UPAPDEBUG(LOG_INFO, ("upap_init: %d\n", unit));
+  u->us_unit         = unit;
+  u->us_user         = NULL;
+  u->us_userlen      = 0;
+  u->us_passwd       = NULL;
+  u->us_passwdlen    = 0;
+  u->us_clientstate  = UPAPCS_INITIAL;
+  u->us_serverstate  = UPAPSS_INITIAL;
+  u->us_id           = 0;
+  u->us_timeouttime  = UPAP_DEFTIMEOUT;
+  u->us_maxtransmits = 10;
+  u->us_reqtimeout   = UPAP_DEFREQTIME;
+}
+
+/*
+ * upap_authwithpeer - Authenticate us with our peer (start client).
+ *
+ * Set new state and send authenticate's.
+ */
+void
+upap_authwithpeer(int unit, char *user, char *password)
+{
+  upap_state *u = &upap[unit];
+
+  UPAPDEBUG(LOG_INFO, ("upap_authwithpeer: %d user=%s password=%s s=%d\n",
+             unit, user, password, u->us_clientstate));
+
+  /* Save the username and password we're given */
+  u->us_user = user;
+  u->us_userlen = (int)strlen(user);
+  u->us_passwd = password;
+  u->us_passwdlen = (int)strlen(password);
+
+  u->us_transmits = 0;
+
+  /* Lower layer up yet? */
+  if (u->us_clientstate == UPAPCS_INITIAL ||
+      u->us_clientstate == UPAPCS_PENDING) {
+    u->us_clientstate = UPAPCS_PENDING;
+    return;
+  }
+
+  upap_sauthreq(u);      /* Start protocol */
+}
+
+
+/*
+ * upap_authpeer - Authenticate our peer (start server).
+ *
+ * Set new state.
+ */
+void
+upap_authpeer(int unit)
+{
+  upap_state *u = &upap[unit];
+
+  /* Lower layer up yet? */
+  if (u->us_serverstate == UPAPSS_INITIAL ||
+      u->us_serverstate == UPAPSS_PENDING) {
+    u->us_serverstate = UPAPSS_PENDING;
+    return;
+  }
+
+  u->us_serverstate = UPAPSS_LISTEN;
+  if (u->us_reqtimeout > 0) {
+    TIMEOUT(upap_reqtimeout, u, u->us_reqtimeout);
+  }
+}
+
+/*
+ * upap_timeout - Retransmission timer for sending auth-reqs expired.
+ */
+static void
+upap_timeout(void *arg)
+{
+  upap_state *u = (upap_state *) arg;
+
+  UPAPDEBUG(LOG_INFO, ("upap_timeout: %d timeout %d expired s=%d\n", 
+        u->us_unit, u->us_timeouttime, u->us_clientstate));
+
+  if (u->us_clientstate != UPAPCS_AUTHREQ) {
+	UPAPDEBUG(LOG_INFO, ("upap_timeout: not in AUTHREQ state!\n"));
+    return;
+  }
+
+  if (u->us_transmits >= u->us_maxtransmits) {
+    /* give up in disgust */
+    UPAPDEBUG(LOG_ERR, ("No response to PAP authenticate-requests\n"));
+    u->us_clientstate = UPAPCS_BADAUTH;
+    auth_withpeer_fail(u->us_unit, PPP_PAP);
+    return;
+  }
+
+  upap_sauthreq(u);    /* Send Authenticate-Request and set upap timeout*/
+}
+
+
+/*
+ * upap_reqtimeout - Give up waiting for the peer to send an auth-req.
+ */
+static void
+upap_reqtimeout(void *arg)
+{
+  upap_state *u = (upap_state *) arg;
+
+  if (u->us_serverstate != UPAPSS_LISTEN) {
+    return; /* huh?? */
+  }
+
+  auth_peer_fail(u->us_unit, PPP_PAP);
+  u->us_serverstate = UPAPSS_BADAUTH;
+}
+
+
+/*
+ * upap_lowerup - The lower layer is up.
+ *
+ * Start authenticating if pending.
+ */
+static void
+upap_lowerup(int unit)
+{
+  upap_state *u = &upap[unit];
+
+  UPAPDEBUG(LOG_INFO, ("upap_lowerup: init %d clientstate s=%d\n", unit, u->us_clientstate));
+
+  if (u->us_clientstate == UPAPCS_INITIAL) {
+    u->us_clientstate = UPAPCS_CLOSED;
+  } else if (u->us_clientstate == UPAPCS_PENDING) {
+    upap_sauthreq(u);  /* send an auth-request */
+    /* now client state is UPAPCS__AUTHREQ */
+  }
+
+  if (u->us_serverstate == UPAPSS_INITIAL) {
+    u->us_serverstate = UPAPSS_CLOSED;
+  } else if (u->us_serverstate == UPAPSS_PENDING) {
+    u->us_serverstate = UPAPSS_LISTEN;
+    if (u->us_reqtimeout > 0) {
+      TIMEOUT(upap_reqtimeout, u, u->us_reqtimeout);
+    }
+  }
+}
+
+
+/*
+ * upap_lowerdown - The lower layer is down.
+ *
+ * Cancel all timeouts.
+ */
+static void
+upap_lowerdown(int unit)
+{
+  upap_state *u = &upap[unit];
+
+  UPAPDEBUG(LOG_INFO, ("upap_lowerdown: %d s=%d\n", unit, u->us_clientstate));
+
+  if (u->us_clientstate == UPAPCS_AUTHREQ) { /* Timeout pending? */
+    UNTIMEOUT(upap_timeout, u);    /* Cancel timeout */
+  }
+  if (u->us_serverstate == UPAPSS_LISTEN && u->us_reqtimeout > 0) {
+    UNTIMEOUT(upap_reqtimeout, u);
+  }
+
+  u->us_clientstate = UPAPCS_INITIAL;
+  u->us_serverstate = UPAPSS_INITIAL;
+}
+
+
+/*
+ * upap_protrej - Peer doesn't speak this protocol.
+ *
+ * This shouldn't happen.  In any case, pretend lower layer went down.
+ */
+static void
+upap_protrej(int unit)
+{
+  upap_state *u = &upap[unit];
+
+  if (u->us_clientstate == UPAPCS_AUTHREQ) {
+    UPAPDEBUG(LOG_ERR, ("PAP authentication failed due to protocol-reject\n"));
+    auth_withpeer_fail(unit, PPP_PAP);
+  }
+  if (u->us_serverstate == UPAPSS_LISTEN) {
+    UPAPDEBUG(LOG_ERR, ("PAP authentication of peer failed (protocol-reject)\n"));
+    auth_peer_fail(unit, PPP_PAP);
+  }
+  upap_lowerdown(unit);
+}
+
+
+/*
+ * upap_input - Input UPAP packet.
+ */
+static void
+upap_input(int unit, u_char *inpacket, int l)
+{
+  upap_state *u = &upap[unit];
+  u_char *inp;
+  u_char code, id;
+  int len;
+
+  /*
+   * Parse header (code, id and length).
+   * If packet too short, drop it.
+   */
+  inp = inpacket;
+  if (l < (int)UPAP_HEADERLEN) {
+    UPAPDEBUG(LOG_INFO, ("pap_input: rcvd short header.\n"));
+    return;
+  }
+  GETCHAR(code, inp);
+  GETCHAR(id, inp);
+  GETSHORT(len, inp);
+  if (len < (int)UPAP_HEADERLEN) {
+    UPAPDEBUG(LOG_INFO, ("pap_input: rcvd illegal length.\n"));
+    return;
+  }
+  if (len > l) {
+    UPAPDEBUG(LOG_INFO, ("pap_input: rcvd short packet.\n"));
+    return;
+  }
+  len -= UPAP_HEADERLEN;
+
+  /*
+   * Action depends on code.
+   */
+  switch (code) {
+    case UPAP_AUTHREQ:
+      upap_rauthreq(u, inp, id, len);
+      break;
+
+    case UPAP_AUTHACK:
+      upap_rauthack(u, inp, id, len);
+      break;
+
+    case UPAP_AUTHNAK:
+      upap_rauthnak(u, inp, id, len);
+      break;
+
+    default:        /* XXX Need code reject */
+      UPAPDEBUG(LOG_INFO, ("pap_input: UNHANDLED default: code: %d, id: %d, len: %d.\n", code, id, len));
+      break;
+  }
+}
+
+
+/*
+ * upap_rauth - Receive Authenticate.
+ */
+static void
+upap_rauthreq(upap_state *u, u_char *inp, u_char id, int len)
+{
+  u_char ruserlen, rpasswdlen;
+  char *ruser, *rpasswd;
+  u_char retcode;
+  char *msg;
+  int msglen;
+
+  UPAPDEBUG(LOG_INFO, ("pap_rauth: Rcvd id %d.\n", id));
+
+  if (u->us_serverstate < UPAPSS_LISTEN) {
+    return;
+  }
+
+  /*
+   * If we receive a duplicate authenticate-request, we are
+   * supposed to return the same status as for the first request.
+   */
+  if (u->us_serverstate == UPAPSS_OPEN) {
+    upap_sresp(u, UPAP_AUTHACK, id, "", 0);  /* return auth-ack */
+    return;
+  }
+  if (u->us_serverstate == UPAPSS_BADAUTH) {
+    upap_sresp(u, UPAP_AUTHNAK, id, "", 0);  /* return auth-nak */
+    return;
+  }
+
+  /*
+   * Parse user/passwd.
+   */
+  if (len < (int)sizeof (u_char)) {
+    UPAPDEBUG(LOG_INFO, ("pap_rauth: rcvd short packet.\n"));
+    return;
+  }
+  GETCHAR(ruserlen, inp);
+  len -= sizeof (u_char) + ruserlen + sizeof (u_char);
+  if (len < 0) {
+    UPAPDEBUG(LOG_INFO, ("pap_rauth: rcvd short packet.\n"));
+    return;
+  }
+  ruser = (char *) inp;
+  INCPTR(ruserlen, inp);
+  GETCHAR(rpasswdlen, inp);
+  if (len < rpasswdlen) {
+    UPAPDEBUG(LOG_INFO, ("pap_rauth: rcvd short packet.\n"));
+    return;
+  }
+  rpasswd = (char *) inp;
+
+  /*
+   * Check the username and password given.
+   */
+  retcode = check_passwd(u->us_unit, ruser, ruserlen, rpasswd, rpasswdlen, &msg, &msglen);
+  /* lwip: currently retcode is always UPAP_AUTHACK */
+  BZERO(rpasswd, rpasswdlen);
+
+  upap_sresp(u, retcode, id, msg, msglen);
+
+  if (retcode == UPAP_AUTHACK) {
+    u->us_serverstate = UPAPSS_OPEN;
+    auth_peer_success(u->us_unit, PPP_PAP, ruser, ruserlen);
+  } else {
+    u->us_serverstate = UPAPSS_BADAUTH;
+    auth_peer_fail(u->us_unit, PPP_PAP);
+  }
+
+  if (u->us_reqtimeout > 0) {
+    UNTIMEOUT(upap_reqtimeout, u);
+  }
+}
+
+
+/*
+ * upap_rauthack - Receive Authenticate-Ack.
+ */
+static void
+upap_rauthack(upap_state *u, u_char *inp, int id, int len)
+{
+  u_char msglen;
+  char *msg;
+
+  LWIP_UNUSED_ARG(id);
+
+  UPAPDEBUG(LOG_INFO, ("pap_rauthack: Rcvd id %d s=%d\n", id, u->us_clientstate));
+
+  if (u->us_clientstate != UPAPCS_AUTHREQ) { /* XXX */
+    UPAPDEBUG(LOG_INFO, ("pap_rauthack: us_clientstate != UPAPCS_AUTHREQ\n"));
+    return;
+  }
+
+  /*
+   * Parse message.
+   */
+  if (len < (int)sizeof (u_char)) {
+    UPAPDEBUG(LOG_INFO, ("pap_rauthack: ignoring missing msg-length.\n"));
+  } else {
+    GETCHAR(msglen, inp);
+    if (msglen > 0) {
+      len -= sizeof (u_char);
+      if (len < msglen) {
+        UPAPDEBUG(LOG_INFO, ("pap_rauthack: rcvd short packet.\n"));
+        return;
+      }
+      msg = (char *) inp;
+      PRINTMSG(msg, msglen);
+    }
+  }
+  UNTIMEOUT(upap_timeout, u);    /* Cancel timeout */
+  u->us_clientstate = UPAPCS_OPEN;
+
+  auth_withpeer_success(u->us_unit, PPP_PAP);
+}
+
+
+/*
+ * upap_rauthnak - Receive Authenticate-Nak.
+ */
+static void
+upap_rauthnak(upap_state *u, u_char *inp, int id, int len)
+{
+  u_char msglen;
+  char *msg;
+
+  LWIP_UNUSED_ARG(id);
+
+  UPAPDEBUG(LOG_INFO, ("pap_rauthnak: Rcvd id %d s=%d\n", id, u->us_clientstate));
+
+  if (u->us_clientstate != UPAPCS_AUTHREQ) { /* XXX */
+    return;
+  }
+
+  /*
+   * Parse message.
+   */
+  if (len < sizeof (u_char)) {
+    UPAPDEBUG(LOG_INFO, ("pap_rauthnak: ignoring missing msg-length.\n"));
+  } else {
+    GETCHAR(msglen, inp);
+    if(msglen > 0) {
+      len -= sizeof (u_char);
+      if (len < msglen) {
+        UPAPDEBUG(LOG_INFO, ("pap_rauthnak: rcvd short packet.\n"));
+        return;
+      }
+      msg = (char *) inp;
+      PRINTMSG(msg, msglen);
+    }
+  }
+
+  u->us_clientstate = UPAPCS_BADAUTH;
+
+  UPAPDEBUG(LOG_ERR, ("PAP authentication failed\n"));
+  auth_withpeer_fail(u->us_unit, PPP_PAP);
+}
+
+
+/*
+ * upap_sauthreq - Send an Authenticate-Request.
+ */
+static void
+upap_sauthreq(upap_state *u)
+{
+  u_char *outp;
+  int outlen;
+
+  outlen = UPAP_HEADERLEN + 2 * sizeof (u_char) 
+         + u->us_userlen + u->us_passwdlen;
+  outp = outpacket_buf[u->us_unit];
+
+  MAKEHEADER(outp, PPP_PAP);
+
+  PUTCHAR(UPAP_AUTHREQ, outp);
+  PUTCHAR(++u->us_id, outp);
+  PUTSHORT(outlen, outp);
+  PUTCHAR(u->us_userlen, outp);
+  BCOPY(u->us_user, outp, u->us_userlen);
+  INCPTR(u->us_userlen, outp);
+  PUTCHAR(u->us_passwdlen, outp);
+  BCOPY(u->us_passwd, outp, u->us_passwdlen);
+
+  pppWrite(u->us_unit, outpacket_buf[u->us_unit], outlen + PPP_HDRLEN);
+
+  UPAPDEBUG(LOG_INFO, ("pap_sauth: Sent id %d\n", u->us_id));
+
+  TIMEOUT(upap_timeout, u, u->us_timeouttime);
+  ++u->us_transmits;
+  u->us_clientstate = UPAPCS_AUTHREQ;
+}
+
+
+/*
+ * upap_sresp - Send a response (ack or nak).
+ */
+static void
+upap_sresp(upap_state *u, u_char code, u_char id, char *msg, int msglen)
+{
+  u_char *outp;
+  int outlen;
+
+  outlen = UPAP_HEADERLEN + sizeof (u_char) + msglen;
+  outp = outpacket_buf[u->us_unit];
+  MAKEHEADER(outp, PPP_PAP);
+
+  PUTCHAR(code, outp);
+  PUTCHAR(id, outp);
+  PUTSHORT(outlen, outp);
+  PUTCHAR(msglen, outp);
+  BCOPY(msg, outp, msglen);
+  pppWrite(u->us_unit, outpacket_buf[u->us_unit], outlen + PPP_HDRLEN);
+
+  UPAPDEBUG(LOG_INFO, ("pap_sresp: Sent code %d, id %d s=%d\n", code, id, u->us_clientstate));
+}
+
+#if PPP_ADDITIONAL_CALLBACKS
+static char *upap_codenames[] = {
+    "AuthReq", "AuthAck", "AuthNak"
+};
+
+/*
+ * upap_printpkt - print the contents of a PAP packet.
+ */
+static int upap_printpkt(
+  u_char *p,
+  int plen,
+  void (*printer) (void *, char *, ...),
+  void *arg
+)
+{
+  LWIP_UNUSED_ARG(p);
+  LWIP_UNUSED_ARG(plen);
+  LWIP_UNUSED_ARG(printer);
+  LWIP_UNUSED_ARG(arg);
+  return 0;
+}
+#endif /* PPP_ADDITIONAL_CALLBACKS */
+
+#endif /* PAP_SUPPORT */
+
+#endif /* PPP_SUPPORT */
diff --git a/core/lwip/src/netif/ppp/pap.h b/core/lwip/src/netif/ppp/pap.h
new file mode 100644
index 00000000..c99a2040
--- /dev/null
+++ b/core/lwip/src/netif/ppp/pap.h
@@ -0,0 +1,118 @@
+/*****************************************************************************
+* pap.h -  PPP Password Authentication Protocol header file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* portions Copyright (c) 1997 Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 97-12-04 Guy Lancaster <glanca@gesn.com>, Global Election Systems Inc.
+*   Original derived from BSD codes.
+*****************************************************************************/
+/*
+ * upap.h - User/Password Authentication Protocol definitions.
+ *
+ * Copyright (c) 1989 Carnegie Mellon University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Carnegie Mellon University.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#ifndef PAP_H
+#define PAP_H
+
+#if PAP_SUPPORT /* don't build if not configured for use in lwipopts.h */
+
+/*
+ * Packet header = Code, id, length.
+ */
+#define UPAP_HEADERLEN (sizeof (u_char) + sizeof (u_char) + sizeof (u_short))
+
+
+/*
+ * UPAP codes.
+ */
+#define UPAP_AUTHREQ 1 /* Authenticate-Request */
+#define UPAP_AUTHACK 2 /* Authenticate-Ack */
+#define UPAP_AUTHNAK 3 /* Authenticate-Nak */
+
+/*
+ * Each interface is described by upap structure.
+ */
+typedef struct upap_state {
+  int us_unit;           /* Interface unit number */
+  const char *us_user;   /* User */
+  int us_userlen;        /* User length */
+  const char *us_passwd; /* Password */
+  int us_passwdlen;      /* Password length */
+  int us_clientstate;    /* Client state */
+  int us_serverstate;    /* Server state */
+  u_char us_id;          /* Current id */
+  int us_timeouttime;    /* Timeout (seconds) for auth-req retrans. */
+  int us_transmits;      /* Number of auth-reqs sent */
+  int us_maxtransmits;   /* Maximum number of auth-reqs to send */
+  int us_reqtimeout;     /* Time to wait for auth-req from peer */
+} upap_state;
+
+/*
+ * Client states.
+ */
+#define UPAPCS_INITIAL 0 /* Connection down */
+#define UPAPCS_CLOSED  1 /* Connection up, haven't requested auth */
+#define UPAPCS_PENDING 2 /* Connection down, have requested auth */
+#define UPAPCS_AUTHREQ 3 /* We've sent an Authenticate-Request */
+#define UPAPCS_OPEN    4 /* We've received an Ack */
+#define UPAPCS_BADAUTH 5 /* We've received a Nak */
+
+/*
+ * Server states.
+ */
+#define UPAPSS_INITIAL 0 /* Connection down */
+#define UPAPSS_CLOSED  1 /* Connection up, haven't requested auth */
+#define UPAPSS_PENDING 2 /* Connection down, have requested auth */
+#define UPAPSS_LISTEN  3 /* Listening for an Authenticate */
+#define UPAPSS_OPEN    4 /* We've sent an Ack */
+#define UPAPSS_BADAUTH 5 /* We've sent a Nak */
+
+
+extern upap_state upap[];
+
+void upap_authwithpeer  (int, char *, char *);
+void upap_authpeer      (int);
+
+extern struct protent pap_protent;
+
+#endif /* PAP_SUPPORT */
+
+#endif /* PAP_H */
diff --git a/core/lwip/src/netif/ppp/ppp.c b/core/lwip/src/netif/ppp/ppp.c
new file mode 100644
index 00000000..e9b433b0
--- /dev/null
+++ b/core/lwip/src/netif/ppp/ppp.c
@@ -0,0 +1,2020 @@
+/*****************************************************************************
+* ppp.c - Network Point to Point Protocol program file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* portions Copyright (c) 1997 by Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 97-11-05 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
+*   Original.
+*****************************************************************************/
+
+/*
+ * ppp_defs.h - PPP definitions.
+ *
+ * if_pppvar.h - private structures and declarations for PPP.
+ *
+ * Copyright (c) 1994 The Australian National University.
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify, and distribute this software and its
+ * documentation is hereby granted, provided that the above copyright
+ * notice appears in all copies.  This software is provided without any
+ * warranty, express or implied. The Australian National University
+ * makes no representations about the suitability of this software for
+ * any purpose.
+ *
+ * IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY
+ * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
+ * THE AUSTRALIAN NATIONAL UNIVERSITY HAVE BEEN ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO
+ * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
+ * OR MODIFICATIONS.
+ */
+
+/*
+ * if_ppp.h - Point-to-Point Protocol definitions.
+ *
+ * Copyright (c) 1989 Carnegie Mellon University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Carnegie Mellon University.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#include "lwip/opt.h"
+
+#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/ip.h" /* for ip_input() */
+
+#include "ppp.h"
+#include "pppdebug.h"
+
+#include "randm.h"
+#include "fsm.h"
+#if PAP_SUPPORT
+#include "pap.h"
+#endif /* PAP_SUPPORT */
+#if CHAP_SUPPORT
+#include "chap.h"
+#endif /* CHAP_SUPPORT */
+#include "ipcp.h"
+#include "lcp.h"
+#include "magic.h"
+#include "auth.h"
+#if VJ_SUPPORT
+#include "vj.h"
+#endif /* VJ_SUPPORT */
+#if PPPOE_SUPPORT
+#include "netif/ppp_oe.h"
+#endif /* PPPOE_SUPPORT */
+
+#include "lwip/tcpip.h"
+#include "lwip/api.h"
+#include "lwip/snmp.h"
+
+#include <string.h>
+
+/*************************/
+/*** LOCAL DEFINITIONS ***/
+/*************************/
+
+/** PPP_INPROC_MULTITHREADED==1 call pppInput using tcpip_callback().
+ * Set this to 0 if pppInProc is called inside tcpip_thread or with NO_SYS==1.
+ * Default is 1 for NO_SYS==0 (multithreaded) and 0 for NO_SYS==1 (single-threaded).
+ */
+#ifndef PPP_INPROC_MULTITHREADED
+#define PPP_INPROC_MULTITHREADED (NO_SYS==0)
+#endif
+
+/** PPP_INPROC_OWNTHREAD==1: start a dedicated RX thread per PPP session.
+ * Default is 0: call pppos_input() for received raw characters, charcater
+ * reception is up to the port */
+#ifndef PPP_INPROC_OWNTHREAD
+#define PPP_INPROC_OWNTHREAD      PPP_INPROC_MULTITHREADED
+#endif
+
+#if PPP_INPROC_OWNTHREAD && !PPP_INPROC_MULTITHREADED
+  #error "PPP_INPROC_OWNTHREAD needs PPP_INPROC_MULTITHREADED==1"
+#endif
+
+/*
+ * The basic PPP frame.
+ */
+#define PPP_ADDRESS(p)  (((u_char *)(p))[0])
+#define PPP_CONTROL(p)  (((u_char *)(p))[1])
+#define PPP_PROTOCOL(p) ((((u_char *)(p))[2] << 8) + ((u_char *)(p))[3])
+
+/* PPP packet parser states.  Current state indicates operation yet to be
+ * completed. */
+typedef enum {
+  PDIDLE = 0,  /* Idle state - waiting. */
+  PDSTART,     /* Process start flag. */
+  PDADDRESS,   /* Process address field. */
+  PDCONTROL,   /* Process control field. */
+  PDPROTOCOL1, /* Process protocol field 1. */
+  PDPROTOCOL2, /* Process protocol field 2. */
+  PDDATA       /* Process data byte. */
+} PPPDevStates;
+
+#define ESCAPE_P(accm, c) ((accm)[(c) >> 3] & pppACCMMask[c & 0x07])
+
+/************************/
+/*** LOCAL DATA TYPES ***/
+/************************/
+
+/** RX buffer size: this may be configured smaller! */
+#ifndef PPPOS_RX_BUFSIZE
+#define PPPOS_RX_BUFSIZE    (PPP_MRU + PPP_HDRLEN)
+#endif
+
+typedef struct PPPControlRx_s {
+  /** unit number / ppp descriptor */
+  int pd;
+  /** the rx file descriptor */
+  sio_fd_t fd;
+  /** receive buffer - encoded data is stored here */
+  u_char rxbuf[PPPOS_RX_BUFSIZE];
+
+  /* The input packet. */
+  struct pbuf *inHead, *inTail;
+
+#if PPPOS_SUPPORT
+  u16_t inProtocol;             /* The input protocol code. */
+  u16_t inFCS;                  /* Input Frame Check Sequence value. */
+#endif /* PPPOS_SUPPORT */
+  PPPDevStates inState;         /* The input process state. */
+  char inEscaped;               /* Escape next character. */
+  ext_accm inACCM;              /* Async-Ctl-Char-Map for input. */
+} PPPControlRx;
+
+/*
+ * PPP interface control block.
+ */
+typedef struct PPPControl_s {
+  PPPControlRx rx;
+  char openFlag;                /* True when in use. */
+#if PPPOE_SUPPORT
+  struct netif *ethif;
+  struct pppoe_softc *pppoe_sc;
+#endif /* PPPOE_SUPPORT */
+  int  if_up;                   /* True when the interface is up. */
+  int  errCode;                 /* Code indicating why interface is down. */
+#if PPPOS_SUPPORT
+  sio_fd_t fd;                  /* File device ID of port. */
+#endif /* PPPOS_SUPPORT */
+  u16_t mtu;                    /* Peer's mru */
+  int  pcomp;                   /* Does peer accept protocol compression? */
+  int  accomp;                  /* Does peer accept addr/ctl compression? */
+  u_long lastXMit;              /* Time of last transmission. */
+  ext_accm outACCM;             /* Async-Ctl-Char-Map for output. */
+#if PPPOS_SUPPORT && VJ_SUPPORT
+  int  vjEnabled;               /* Flag indicating VJ compression enabled. */
+  struct vjcompress vjComp;     /* Van Jacobson compression header. */
+#endif /* PPPOS_SUPPORT && VJ_SUPPORT */
+
+  struct netif netif;
+
+  struct ppp_addrs addrs;
+
+  void (*linkStatusCB)(void *ctx, int errCode, void *arg);
+  void *linkStatusCtx;
+
+} PPPControl;
+
+
+/*
+ * Ioctl definitions.
+ */
+
+struct npioctl {
+  int         protocol; /* PPP procotol, e.g. PPP_IP */
+  enum NPmode mode;
+};
+
+
+
+/***********************************/
+/*** LOCAL FUNCTION DECLARATIONS ***/
+/***********************************/
+#if PPPOS_SUPPORT
+#if PPP_INPROC_OWNTHREAD
+static void pppInputThread(void *arg);
+#endif /* PPP_INPROC_OWNTHREAD */
+static void pppDrop(PPPControlRx *pcrx);
+static void pppInProc(PPPControlRx *pcrx, u_char *s, int l);
+#endif /* PPPOS_SUPPORT */
+
+
+/******************************/
+/*** PUBLIC DATA STRUCTURES ***/
+/******************************/
+u_long subnetMask;
+
+static PPPControl pppControl[NUM_PPP]; /* The PPP interface control blocks. */
+
+/*
+ * PPP Data Link Layer "protocol" table.
+ * One entry per supported protocol.
+ * The last entry must be NULL.
+ */
+struct protent *ppp_protocols[] = {
+  &lcp_protent,
+#if PAP_SUPPORT
+  &pap_protent,
+#endif /* PAP_SUPPORT */
+#if CHAP_SUPPORT
+  &chap_protent,
+#endif /* CHAP_SUPPORT */
+#if CBCP_SUPPORT
+  &cbcp_protent,
+#endif /* CBCP_SUPPORT */
+  &ipcp_protent,
+#if CCP_SUPPORT
+  &ccp_protent,
+#endif /* CCP_SUPPORT */
+  NULL
+};
+
+
+/*
+ * Buffers for outgoing packets.  This must be accessed only from the appropriate
+ * PPP task so that it doesn't need to be protected to avoid collisions.
+ */
+u_char outpacket_buf[NUM_PPP][PPP_MRU+PPP_HDRLEN];
+
+
+/*****************************/
+/*** LOCAL DATA STRUCTURES ***/
+/*****************************/
+
+#if PPPOS_SUPPORT
+/*
+ * FCS lookup table as calculated by genfcstab.
+ * @todo: smaller, slower implementation for lower memory footprint?
+ */
+static const u_short fcstab[256] = {
+  0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
+  0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
+  0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
+  0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
+  0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
+  0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
+  0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
+  0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
+  0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
+  0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
+  0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
+  0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
+  0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
+  0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
+  0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
+  0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
+  0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
+  0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
+  0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
+  0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
+  0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
+  0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
+  0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
+  0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
+  0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
+  0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
+  0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
+  0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
+  0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
+  0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
+  0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
+  0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
+};
+
+/* PPP's Asynchronous-Control-Character-Map.  The mask array is used
+ * to select the specific bit for a character. */
+static u_char pppACCMMask[] = {
+  0x01,
+  0x02,
+  0x04,
+  0x08,
+  0x10,
+  0x20,
+  0x40,
+  0x80
+};
+
+/** Wake up the task blocked in reading from serial line (if any) */
+static void
+pppRecvWakeup(int pd)
+{
+  PPPDEBUG(LOG_DEBUG, ("pppRecvWakeup: unit %d\n", pd));
+  if (pppControl[pd].openFlag != 0) {
+    sio_read_abort(pppControl[pd].fd);
+  }
+}
+#endif /* PPPOS_SUPPORT */
+
+void
+pppLinkTerminated(int pd)
+{
+  PPPDEBUG(LOG_DEBUG, ("pppLinkTerminated: unit %d\n", pd));
+
+#if PPPOE_SUPPORT
+  if (pppControl[pd].ethif) {
+    pppoe_disconnect(pppControl[pd].pppoe_sc);
+  } else
+#endif /* PPPOE_SUPPORT */
+  {
+#if PPPOS_SUPPORT
+    PPPControl* pc;
+    pppRecvWakeup(pd);
+    pc = &pppControl[pd];
+
+    PPPDEBUG(LOG_DEBUG, ("pppLinkTerminated: unit %d: linkStatusCB=%p errCode=%d\n", pd, pc->linkStatusCB, pc->errCode));
+    if (pc->linkStatusCB) {
+      pc->linkStatusCB(pc->linkStatusCtx, pc->errCode ? pc->errCode : PPPERR_PROTOCOL, NULL);
+    }
+
+    pc->openFlag = 0;/**/
+#endif /* PPPOS_SUPPORT */
+  }
+  PPPDEBUG(LOG_DEBUG, ("pppLinkTerminated: finished.\n"));
+}
+
+void
+pppLinkDown(int pd)
+{
+  PPPDEBUG(LOG_DEBUG, ("pppLinkDown: unit %d\n", pd));
+
+#if PPPOE_SUPPORT
+  if (pppControl[pd].ethif) {
+    pppoe_disconnect(pppControl[pd].pppoe_sc);
+  } else
+#endif /* PPPOE_SUPPORT */
+  {
+#if PPPOS_SUPPORT
+    pppRecvWakeup(pd);
+#endif /* PPPOS_SUPPORT */
+  }
+}
+
+/** Initiate LCP open request */
+static void
+pppStart(int pd)
+{
+  PPPDEBUG(LOG_DEBUG, ("pppStart: unit %d\n", pd));
+  lcp_lowerup(pd);
+  lcp_open(pd); /* Start protocol */
+  PPPDEBUG(LOG_DEBUG, ("pppStart: finished\n"));
+}
+
+/** LCP close request */
+static void
+pppStop(int pd)
+{
+  PPPDEBUG(LOG_DEBUG, ("pppStop: unit %d\n", pd));
+  lcp_close(pd, "User request");
+}
+
+/** Called when carrier/link is lost */
+static void
+pppHup(int pd)
+{
+  PPPDEBUG(LOG_DEBUG, ("pppHupCB: unit %d\n", pd));
+  lcp_lowerdown(pd);
+  link_terminated(pd);
+}
+
+/***********************************/
+/*** PUBLIC FUNCTION DEFINITIONS ***/
+/***********************************/
+/* Initialize the PPP subsystem. */
+
+struct ppp_settings ppp_settings;
+
+void
+pppInit(void)
+{
+  struct protent *protp;
+  int i, j;
+
+  memset(&ppp_settings, 0, sizeof(ppp_settings));
+  ppp_settings.usepeerdns = 1;
+  pppSetAuth(PPPAUTHTYPE_NONE, NULL, NULL);
+
+  magicInit();
+
+  subnetMask = PP_HTONL(0xffffff00UL);
+
+  for (i = 0; i < NUM_PPP; i++) {
+    /* Initialize each protocol to the standard option set. */
+    for (j = 0; (protp = ppp_protocols[j]) != NULL; ++j) {
+      (*protp->init)(i);
+    }
+  }
+}
+
+void
+pppSetAuth(enum pppAuthType authType, const char *user, const char *passwd)
+{
+  switch(authType) {
+    case PPPAUTHTYPE_NONE:
+    default:
+#ifdef LWIP_PPP_STRICT_PAP_REJECT
+      ppp_settings.refuse_pap = 1;
+#else  /* LWIP_PPP_STRICT_PAP_REJECT */
+      /* some providers request pap and accept an empty login/pw */
+      ppp_settings.refuse_pap = 0;
+#endif /* LWIP_PPP_STRICT_PAP_REJECT */
+      ppp_settings.refuse_chap = 1;
+      break;
+
+    case PPPAUTHTYPE_ANY:
+      /* Warning: Using PPPAUTHTYPE_ANY might have security consequences.
+       * RFC 1994 says:
+       *
+       * In practice, within or associated with each PPP server, there is a
+       * database which associates "user" names with authentication
+       * information ("secrets").  It is not anticipated that a particular
+       * named user would be authenticated by multiple methods.  This would
+       * make the user vulnerable to attacks which negotiate the least secure
+       * method from among a set (such as PAP rather than CHAP).  If the same
+       * secret was used, PAP would reveal the secret to be used later with
+       * CHAP.
+       *
+       * Instead, for each user name there should be an indication of exactly
+       * one method used to authenticate that user name.  If a user needs to
+       * make use of different authentication methods under different
+       * circumstances, then distinct user names SHOULD be employed, each of
+       * which identifies exactly one authentication method.
+       *
+       */
+      ppp_settings.refuse_pap = 0;
+      ppp_settings.refuse_chap = 0;
+      break;
+
+    case PPPAUTHTYPE_PAP:
+      ppp_settings.refuse_pap = 0;
+      ppp_settings.refuse_chap = 1;
+      break;
+
+    case PPPAUTHTYPE_CHAP:
+      ppp_settings.refuse_pap = 1;
+      ppp_settings.refuse_chap = 0;
+      break;
+  }
+
+  if(user) {
+    strncpy(ppp_settings.user, user, sizeof(ppp_settings.user)-1);
+    ppp_settings.user[sizeof(ppp_settings.user)-1] = '\0';
+  } else {
+    ppp_settings.user[0] = '\0';
+  }
+
+  if(passwd) {
+    strncpy(ppp_settings.passwd, passwd, sizeof(ppp_settings.passwd)-1);
+    ppp_settings.passwd[sizeof(ppp_settings.passwd)-1] = '\0';
+  } else {
+    ppp_settings.passwd[0] = '\0';
+  }
+}
+
+#if PPPOS_SUPPORT
+/** Open a new PPP connection using the given I/O device.
+ * This initializes the PPP control block but does not
+ * attempt to negotiate the LCP session.  If this port
+ * connects to a modem, the modem connection must be
+ * established before calling this.
+ * Return a new PPP connection descriptor on success or
+ * an error code (negative) on failure.
+ *
+ * pppOpen() is directly defined to this function.
+ */
+int
+pppOverSerialOpen(sio_fd_t fd, void (*linkStatusCB)(void *ctx, int errCode, void *arg), void *linkStatusCtx)
+{
+  PPPControl *pc;
+  int pd;
+
+  if (linkStatusCB == NULL) {
+    /* PPP is single-threaded: without a callback,
+     * there is no way to know when the link is up. */
+    return PPPERR_PARAM;
+  }
+
+  /* Find a free PPP session descriptor. */
+  for (pd = 0; pd < NUM_PPP && pppControl[pd].openFlag != 0; pd++);
+
+  if (pd >= NUM_PPP) {
+    pd = PPPERR_OPEN;
+  } else {
+    pc = &pppControl[pd];
+    /* @todo: is this correct or do I overwrite something? */
+    memset(pc, 0, sizeof(PPPControl));
+    pc->rx.pd = pd;
+    pc->rx.fd = fd;
+
+    pc->openFlag = 1;
+    pc->fd = fd;
+
+#if VJ_SUPPORT
+    vj_compress_init(&pc->vjComp);
+#endif /* VJ_SUPPORT */
+
+    /* 
+     * Default the in and out accm so that escape and flag characters
+     * are always escaped. 
+     */
+    pc->rx.inACCM[15] = 0x60; /* no need to protect since RX is not running */
+    pc->outACCM[15] = 0x60;
+
+    pc->linkStatusCB = linkStatusCB;
+    pc->linkStatusCtx = linkStatusCtx;
+
+    /*
+     * Start the connection and handle incoming events (packet or timeout).
+     */
+    PPPDEBUG(LOG_INFO, ("pppOverSerialOpen: unit %d: Connecting\n", pd));
+    pppStart(pd);
+#if PPP_INPROC_OWNTHREAD
+    sys_thread_new(PPP_THREAD_NAME, pppInputThread, (void*)&pc->rx, PPP_THREAD_STACKSIZE, PPP_THREAD_PRIO);
+#endif
+  }
+
+  return pd;
+}
+#endif /* PPPOS_SUPPORT */
+
+#if PPPOE_SUPPORT
+static void pppOverEthernetLinkStatusCB(int pd, int up);
+
+void
+pppOverEthernetClose(int pd)
+{
+  PPPControl* pc = &pppControl[pd];
+
+  /* *TJL* There's no lcp_deinit */
+  lcp_close(pd, NULL);
+
+  pppoe_destroy(&pc->netif);
+}
+
+int pppOverEthernetOpen(struct netif *ethif, const char *service_name, const char *concentrator_name, void (*linkStatusCB)(void *ctx, int errCode, void *arg), void *linkStatusCtx)
+{
+  PPPControl *pc;
+  int pd;
+
+  LWIP_UNUSED_ARG(service_name);
+  LWIP_UNUSED_ARG(concentrator_name);
+
+  if (linkStatusCB == NULL) {
+    /* PPP is single-threaded: without a callback,
+     * there is no way to know when the link is up. */
+    return PPPERR_PARAM;
+  }
+
+  /* Find a free PPP session descriptor. Critical region? */
+  for (pd = 0; pd < NUM_PPP && pppControl[pd].openFlag != 0; pd++);
+  if (pd >= NUM_PPP) {
+    pd = PPPERR_OPEN;
+  } else {
+    pc = &pppControl[pd];
+    memset(pc, 0, sizeof(PPPControl));
+    pc->openFlag = 1;
+    pc->ethif = ethif;
+
+    pc->linkStatusCB  = linkStatusCB;
+    pc->linkStatusCtx = linkStatusCtx;
+
+    lcp_wantoptions[pd].mru = PPPOE_MAXMTU;
+    lcp_wantoptions[pd].neg_asyncmap = 0;
+    lcp_wantoptions[pd].neg_pcompression = 0;
+    lcp_wantoptions[pd].neg_accompression = 0;
+
+    lcp_allowoptions[pd].mru = PPPOE_MAXMTU;
+    lcp_allowoptions[pd].neg_asyncmap = 0;
+    lcp_allowoptions[pd].neg_pcompression = 0;
+    lcp_allowoptions[pd].neg_accompression = 0;
+
+    if(pppoe_create(ethif, pd, pppOverEthernetLinkStatusCB, &pc->pppoe_sc) != ERR_OK) {
+      pc->openFlag = 0;
+      return PPPERR_OPEN;
+    }
+
+    pppoe_connect(pc->pppoe_sc);
+  }
+
+  return pd;
+}
+#endif /* PPPOE_SUPPORT */
+
+
+/* Close a PPP connection and release the descriptor. 
+ * Any outstanding packets in the queues are dropped.
+ * Return 0 on success, an error code on failure. */
+int
+pppClose(int pd)
+{
+  PPPControl *pc = &pppControl[pd];
+  int st = 0;
+
+  PPPDEBUG(LOG_DEBUG, ("pppClose() called\n"));
+
+  /* Disconnect */
+#if PPPOE_SUPPORT
+  if(pc->ethif) {
+    PPPDEBUG(LOG_DEBUG, ("pppClose: unit %d kill_link -> pppStop\n", pd));
+    pc->errCode = PPPERR_USER;
+    /* This will leave us at PHASE_DEAD. */
+    pppStop(pd);
+  } else
+#endif /* PPPOE_SUPPORT */
+  {
+#if PPPOS_SUPPORT
+    PPPDEBUG(LOG_DEBUG, ("pppClose: unit %d kill_link -> pppStop\n", pd));
+    pc->errCode = PPPERR_USER;
+    /* This will leave us at PHASE_DEAD. */
+    pppStop(pd);
+    pppRecvWakeup(pd);
+#endif /* PPPOS_SUPPORT */
+  }
+
+  return st;
+}
+
+/* This function is called when carrier is lost on the PPP channel. */
+void
+pppSigHUP(int pd)
+{
+  PPPDEBUG(LOG_DEBUG, ("pppSigHUP: unit %d sig_hup -> pppHupCB\n", pd));
+  pppHup(pd);
+}
+
+#if PPPOS_SUPPORT
+static void
+nPut(PPPControl *pc, struct pbuf *nb)
+{
+  struct pbuf *b;
+  int c;
+
+  for(b = nb; b != NULL; b = b->next) {
+    if((c = sio_write(pc->fd, b->payload, b->len)) != b->len) {
+      PPPDEBUG(LOG_WARNING,
+               ("PPP nPut: incomplete sio_write(fd:%"SZT_F", len:%d, c: 0x%"X8_F") c = %d\n", (size_t)pc->fd, b->len, c, c));
+      LINK_STATS_INC(link.err);
+      pc->lastXMit = 0; /* prepend PPP_FLAG to next packet */
+      snmp_inc_ifoutdiscards(&pc->netif);
+      pbuf_free(nb);
+      return;
+    }
+  }
+
+  snmp_add_ifoutoctets(&pc->netif, nb->tot_len);
+  snmp_inc_ifoutucastpkts(&pc->netif);
+  pbuf_free(nb);
+  LINK_STATS_INC(link.xmit);
+}
+
+/* 
+ * pppAppend - append given character to end of given pbuf.  If outACCM
+ * is not NULL and the character needs to be escaped, do so.
+ * If pbuf is full, append another.
+ * Return the current pbuf.
+ */
+static struct pbuf *
+pppAppend(u_char c, struct pbuf *nb, ext_accm *outACCM)
+{
+  struct pbuf *tb = nb;
+  
+  /* Make sure there is room for the character and an escape code.
+   * Sure we don't quite fill the buffer if the character doesn't
+   * get escaped but is one character worth complicating this? */
+  /* Note: We assume no packet header. */
+  if (nb && (PBUF_POOL_BUFSIZE - nb->len) < 2) {
+    tb = pbuf_alloc(PBUF_RAW, 0, PBUF_POOL);
+    if (tb) {
+      nb->next = tb;
+    } else {
+      LINK_STATS_INC(link.memerr);
+    }
+    nb = tb;
+  }
+
+  if (nb) {
+    if (outACCM && ESCAPE_P(*outACCM, c)) {
+      *((u_char*)nb->payload + nb->len++) = PPP_ESCAPE;
+      *((u_char*)nb->payload + nb->len++) = c ^ PPP_TRANS;
+    } else {
+      *((u_char*)nb->payload + nb->len++) = c;
+    }
+  }
+
+  return tb;
+}
+#endif /* PPPOS_SUPPORT */
+
+#if PPPOE_SUPPORT
+static err_t
+pppifOutputOverEthernet(int pd, struct pbuf *p)
+{
+  PPPControl *pc = &pppControl[pd];
+  struct pbuf *pb;
+  u_short protocol = PPP_IP;
+  int i=0;
+  u16_t tot_len;
+
+  /* @todo: try to use pbuf_header() here! */
+  pb = pbuf_alloc(PBUF_LINK, PPPOE_HDRLEN + sizeof(protocol), PBUF_RAM);
+  if(!pb) {
+    LINK_STATS_INC(link.memerr);
+    LINK_STATS_INC(link.proterr);
+    snmp_inc_ifoutdiscards(&pc->netif);
+    return ERR_MEM;
+  }
+
+  pbuf_header(pb, -(s16_t)PPPOE_HDRLEN);
+
+  pc->lastXMit = sys_jiffies();
+
+  if (!pc->pcomp || protocol > 0xFF) {
+    *((u_char*)pb->payload + i++) = (protocol >> 8) & 0xFF;
+  }
+  *((u_char*)pb->payload + i) = protocol & 0xFF;
+
+  pbuf_chain(pb, p);
+  tot_len = pb->tot_len;
+
+  if(pppoe_xmit(pc->pppoe_sc, pb) != ERR_OK) {
+    LINK_STATS_INC(link.err);
+    snmp_inc_ifoutdiscards(&pc->netif);
+    return PPPERR_DEVICE;
+  }
+
+  snmp_add_ifoutoctets(&pc->netif, tot_len);
+  snmp_inc_ifoutucastpkts(&pc->netif);
+  LINK_STATS_INC(link.xmit);
+  return ERR_OK;
+}
+#endif /* PPPOE_SUPPORT */
+
+/* Send a packet on the given connection. */
+static err_t
+pppifOutput(struct netif *netif, struct pbuf *pb, ip_addr_t *ipaddr)
+{
+  int pd = (int)(size_t)netif->state;
+  PPPControl *pc = &pppControl[pd];
+#if PPPOS_SUPPORT
+  u_short protocol = PPP_IP;
+  u_int fcsOut = PPP_INITFCS;
+  struct pbuf *headMB = NULL, *tailMB = NULL, *p;
+  u_char c;
+#endif /* PPPOS_SUPPORT */
+
+  LWIP_UNUSED_ARG(ipaddr);
+
+  /* Validate parameters. */
+  /* We let any protocol value go through - it can't hurt us
+   * and the peer will just drop it if it's not accepting it. */
+  if (pd < 0 || pd >= NUM_PPP || !pc->openFlag || !pb) {
+    PPPDEBUG(LOG_WARNING, ("pppifOutput[%d]: bad parms prot=%d pb=%p\n",
+              pd, PPP_IP, pb));
+    LINK_STATS_INC(link.opterr);
+    LINK_STATS_INC(link.drop);
+    snmp_inc_ifoutdiscards(netif);
+    return ERR_ARG;
+  }
+
+  /* Check that the link is up. */
+  if (lcp_phase[pd] == PHASE_DEAD) {
+    PPPDEBUG(LOG_ERR, ("pppifOutput[%d]: link not up\n", pd));
+    LINK_STATS_INC(link.rterr);
+    LINK_STATS_INC(link.drop);
+    snmp_inc_ifoutdiscards(netif);
+    return ERR_RTE;
+  }
+
+#if PPPOE_SUPPORT
+  if(pc->ethif) {
+    return pppifOutputOverEthernet(pd, pb);
+  }
+#endif /* PPPOE_SUPPORT */
+
+#if PPPOS_SUPPORT
+  /* Grab an output buffer. */
+  headMB = pbuf_alloc(PBUF_RAW, 0, PBUF_POOL);
+  if (headMB == NULL) {
+    PPPDEBUG(LOG_WARNING, ("pppifOutput[%d]: first alloc fail\n", pd));
+    LINK_STATS_INC(link.memerr);
+    LINK_STATS_INC(link.drop);
+    snmp_inc_ifoutdiscards(netif);
+    return ERR_MEM;
+  }
+
+#if VJ_SUPPORT
+  /* 
+   * Attempt Van Jacobson header compression if VJ is configured and
+   * this is an IP packet. 
+   */
+  if (protocol == PPP_IP && pc->vjEnabled) {
+    switch (vj_compress_tcp(&pc->vjComp, pb)) {
+      case TYPE_IP:
+        /* No change...
+           protocol = PPP_IP_PROTOCOL; */
+        break;
+      case TYPE_COMPRESSED_TCP:
+        protocol = PPP_VJC_COMP;
+        break;
+      case TYPE_UNCOMPRESSED_TCP:
+        protocol = PPP_VJC_UNCOMP;
+        break;
+      default:
+        PPPDEBUG(LOG_WARNING, ("pppifOutput[%d]: bad IP packet\n", pd));
+        LINK_STATS_INC(link.proterr);
+        LINK_STATS_INC(link.drop);
+        snmp_inc_ifoutdiscards(netif);
+        pbuf_free(headMB);
+        return ERR_VAL;
+    }
+  }
+#endif /* VJ_SUPPORT */
+
+  tailMB = headMB;
+
+  /* Build the PPP header. */
+  if ((sys_jiffies() - pc->lastXMit) >= PPP_MAXIDLEFLAG) {
+    tailMB = pppAppend(PPP_FLAG, tailMB, NULL);
+  }
+
+  pc->lastXMit = sys_jiffies();
+  if (!pc->accomp) {
+    fcsOut = PPP_FCS(fcsOut, PPP_ALLSTATIONS);
+    tailMB = pppAppend(PPP_ALLSTATIONS, tailMB, &pc->outACCM);
+    fcsOut = PPP_FCS(fcsOut, PPP_UI);
+    tailMB = pppAppend(PPP_UI, tailMB, &pc->outACCM);
+  }
+  if (!pc->pcomp || protocol > 0xFF) {
+    c = (protocol >> 8) & 0xFF;
+    fcsOut = PPP_FCS(fcsOut, c);
+    tailMB = pppAppend(c, tailMB, &pc->outACCM);
+  }
+  c = protocol & 0xFF;
+  fcsOut = PPP_FCS(fcsOut, c);
+  tailMB = pppAppend(c, tailMB, &pc->outACCM);
+
+  /* Load packet. */
+  for(p = pb; p; p = p->next) {
+    int n;
+    u_char *sPtr;
+
+    sPtr = (u_char*)p->payload;
+    n = p->len;
+    while (n-- > 0) {
+      c = *sPtr++;
+
+      /* Update FCS before checking for special characters. */
+      fcsOut = PPP_FCS(fcsOut, c);
+      
+      /* Copy to output buffer escaping special characters. */
+      tailMB = pppAppend(c, tailMB, &pc->outACCM);
+    }
+  }
+
+  /* Add FCS and trailing flag. */
+  c = ~fcsOut & 0xFF;
+  tailMB = pppAppend(c, tailMB, &pc->outACCM);
+  c = (~fcsOut >> 8) & 0xFF;
+  tailMB = pppAppend(c, tailMB, &pc->outACCM);
+  tailMB = pppAppend(PPP_FLAG, tailMB, NULL);
+
+  /* If we failed to complete the packet, throw it away. */
+  if (!tailMB) {
+    PPPDEBUG(LOG_WARNING,
+             ("pppifOutput[%d]: Alloc err - dropping proto=%d\n", 
+              pd, protocol));
+    pbuf_free(headMB);
+    LINK_STATS_INC(link.memerr);
+    LINK_STATS_INC(link.drop);
+    snmp_inc_ifoutdiscards(netif);
+    return ERR_MEM;
+  }
+
+  /* Send it. */
+  PPPDEBUG(LOG_INFO, ("pppifOutput[%d]: proto=0x%"X16_F"\n", pd, protocol));
+
+  nPut(pc, headMB);
+#endif /* PPPOS_SUPPORT */
+
+  return ERR_OK;
+}
+
+/* Get and set parameters for the given connection.
+ * Return 0 on success, an error code on failure. */
+int
+pppIOCtl(int pd, int cmd, void *arg)
+{
+  PPPControl *pc = &pppControl[pd];
+  int st = 0;
+
+  if (pd < 0 || pd >= NUM_PPP) {
+    st = PPPERR_PARAM;
+  } else {
+    switch(cmd) {
+    case PPPCTLG_UPSTATUS:      /* Get the PPP up status. */
+      if (arg) {
+        *(int *)arg = (int)(pc->if_up);
+      } else {
+        st = PPPERR_PARAM;
+      }
+      break;
+    case PPPCTLS_ERRCODE:       /* Set the PPP error code. */
+      if (arg) {
+        pc->errCode = *(int *)arg;
+      } else {
+        st = PPPERR_PARAM;
+      }
+      break;
+    case PPPCTLG_ERRCODE:       /* Get the PPP error code. */
+      if (arg) {
+        *(int *)arg = (int)(pc->errCode);
+      } else {
+        st = PPPERR_PARAM;
+      }
+      break;
+#if PPPOS_SUPPORT
+    case PPPCTLG_FD:            /* Get the fd associated with the ppp */
+      if (arg) {
+        *(sio_fd_t *)arg = pc->fd;
+      } else {
+        st = PPPERR_PARAM;
+      }
+      break;
+#endif /* PPPOS_SUPPORT */
+    default:
+      st = PPPERR_PARAM;
+      break;
+    }
+  }
+
+  return st;
+}
+
+/*
+ * Return the Maximum Transmission Unit for the given PPP connection.
+ */
+u_short
+pppMTU(int pd)
+{
+  PPPControl *pc = &pppControl[pd];
+  u_short st;
+
+  /* Validate parameters. */
+  if (pd < 0 || pd >= NUM_PPP || !pc->openFlag) {
+    st = 0;
+  } else {
+    st = pc->mtu;
+  }
+
+  return st;
+}
+
+#if PPPOE_SUPPORT
+int
+pppWriteOverEthernet(int pd, const u_char *s, int n)
+{
+  PPPControl *pc = &pppControl[pd];
+  struct pbuf *pb;
+
+  /* skip address & flags */
+  s += 2;
+  n -= 2;
+
+  LWIP_ASSERT("PPPOE_HDRLEN + n <= 0xffff", PPPOE_HDRLEN + n <= 0xffff);
+  pb = pbuf_alloc(PBUF_LINK, (u16_t)(PPPOE_HDRLEN + n), PBUF_RAM);
+  if(!pb) {
+    LINK_STATS_INC(link.memerr);
+    LINK_STATS_INC(link.proterr);
+    snmp_inc_ifoutdiscards(&pc->netif);
+    return PPPERR_ALLOC;
+  }
+
+  pbuf_header(pb, -(s16_t)PPPOE_HDRLEN);
+
+  pc->lastXMit = sys_jiffies();
+
+  MEMCPY(pb->payload, s, n);
+
+  if(pppoe_xmit(pc->pppoe_sc, pb) != ERR_OK) {
+    LINK_STATS_INC(link.err);
+    snmp_inc_ifoutdiscards(&pc->netif);
+    return PPPERR_DEVICE;
+  }
+
+  snmp_add_ifoutoctets(&pc->netif, (u16_t)n);
+  snmp_inc_ifoutucastpkts(&pc->netif);
+  LINK_STATS_INC(link.xmit);
+  return PPPERR_NONE;
+}
+#endif /* PPPOE_SUPPORT */
+
+/*
+ * Write n characters to a ppp link.
+ *  RETURN: >= 0 Number of characters written
+ *           -1 Failed to write to device
+ */
+int
+pppWrite(int pd, const u_char *s, int n)
+{
+  PPPControl *pc = &pppControl[pd];
+#if PPPOS_SUPPORT
+  u_char c;
+  u_int fcsOut;
+  struct pbuf *headMB, *tailMB;
+#endif /* PPPOS_SUPPORT */
+
+#if PPPOE_SUPPORT
+  if(pc->ethif) {
+    return pppWriteOverEthernet(pd, s, n);
+  }
+#endif /* PPPOE_SUPPORT */
+
+#if PPPOS_SUPPORT
+  headMB = pbuf_alloc(PBUF_RAW, 0, PBUF_POOL);
+  if (headMB == NULL) {
+    LINK_STATS_INC(link.memerr);
+    LINK_STATS_INC(link.proterr);
+    snmp_inc_ifoutdiscards(&pc->netif);
+    return PPPERR_ALLOC;
+  }
+
+  tailMB = headMB;
+
+  /* If the link has been idle, we'll send a fresh flag character to
+   * flush any noise. */
+  if ((sys_jiffies() - pc->lastXMit) >= PPP_MAXIDLEFLAG) {
+    tailMB = pppAppend(PPP_FLAG, tailMB, NULL);
+  }
+  pc->lastXMit = sys_jiffies();
+
+  fcsOut = PPP_INITFCS;
+  /* Load output buffer. */
+  while (n-- > 0) {
+    c = *s++;
+
+    /* Update FCS before checking for special characters. */
+    fcsOut = PPP_FCS(fcsOut, c);
+
+    /* Copy to output buffer escaping special characters. */
+    tailMB = pppAppend(c, tailMB, &pc->outACCM);
+  }
+    
+  /* Add FCS and trailing flag. */
+  c = ~fcsOut & 0xFF;
+  tailMB = pppAppend(c, tailMB, &pc->outACCM);
+  c = (~fcsOut >> 8) & 0xFF;
+  tailMB = pppAppend(c, tailMB, &pc->outACCM);
+  tailMB = pppAppend(PPP_FLAG, tailMB, NULL);
+
+  /* If we failed to complete the packet, throw it away.
+   * Otherwise send it. */
+  if (!tailMB) {
+    PPPDEBUG(LOG_WARNING,
+             ("pppWrite[%d]: Alloc err - dropping pbuf len=%d\n", pd, headMB->len));
+           /*"pppWrite[%d]: Alloc err - dropping %d:%.*H", pd, headMB->len, LWIP_MIN(headMB->len * 2, 40), headMB->payload)); */
+    pbuf_free(headMB);
+    LINK_STATS_INC(link.memerr);
+    LINK_STATS_INC(link.proterr);
+    snmp_inc_ifoutdiscards(&pc->netif);
+    return PPPERR_ALLOC;
+  }
+
+  PPPDEBUG(LOG_INFO, ("pppWrite[%d]: len=%d\n", pd, headMB->len));
+                   /* "pppWrite[%d]: %d:%.*H", pd, headMB->len, LWIP_MIN(headMB->len * 2, 40), headMB->payload)); */
+  nPut(pc, headMB);
+#endif /* PPPOS_SUPPORT */
+
+  return PPPERR_NONE;
+}
+
+/*
+ * ppp_send_config - configure the transmit characteristics of
+ * the ppp interface.
+ */
+void
+ppp_send_config( int unit, u16_t mtu, u32_t asyncmap, int pcomp, int accomp)
+{
+  PPPControl *pc = &pppControl[unit];
+  int i;
+  
+  pc->mtu = mtu;
+  pc->pcomp = pcomp;
+  pc->accomp = accomp;
+  
+  /* Load the ACCM bits for the 32 control codes. */
+  for (i = 0; i < 32/8; i++) {
+    pc->outACCM[i] = (u_char)((asyncmap >> (8 * i)) & 0xFF);
+  }
+  PPPDEBUG(LOG_INFO, ("ppp_send_config[%d]: outACCM=%X %X %X %X\n",
+            unit,
+            pc->outACCM[0], pc->outACCM[1], pc->outACCM[2], pc->outACCM[3]));
+}
+
+
+/*
+ * ppp_set_xaccm - set the extended transmit ACCM for the interface.
+ */
+void
+ppp_set_xaccm(int unit, ext_accm *accm)
+{
+  SMEMCPY(pppControl[unit].outACCM, accm, sizeof(ext_accm));
+  PPPDEBUG(LOG_INFO, ("ppp_set_xaccm[%d]: outACCM=%X %X %X %X\n",
+            unit,
+            pppControl[unit].outACCM[0],
+            pppControl[unit].outACCM[1],
+            pppControl[unit].outACCM[2],
+            pppControl[unit].outACCM[3]));
+}
+
+
+/*
+ * ppp_recv_config - configure the receive-side characteristics of
+ * the ppp interface.
+ */
+void
+ppp_recv_config( int unit, int mru, u32_t asyncmap, int pcomp, int accomp)
+{
+  PPPControl *pc = &pppControl[unit];
+  int i;
+  SYS_ARCH_DECL_PROTECT(lev);
+
+  LWIP_UNUSED_ARG(accomp);
+  LWIP_UNUSED_ARG(pcomp);
+  LWIP_UNUSED_ARG(mru);
+
+  /* Load the ACCM bits for the 32 control codes. */
+  SYS_ARCH_PROTECT(lev);
+  for (i = 0; i < 32 / 8; i++) {
+    /* @todo: does this work? ext_accm has been modified from pppd! */
+    pc->rx.inACCM[i] = (u_char)(asyncmap >> (i * 8));
+  }
+  SYS_ARCH_UNPROTECT(lev);
+  PPPDEBUG(LOG_INFO, ("ppp_recv_config[%d]: inACCM=%X %X %X %X\n",
+            unit,
+            pc->rx.inACCM[0], pc->rx.inACCM[1], pc->rx.inACCM[2], pc->rx.inACCM[3]));
+}
+
+#if 0
+/*
+ * ccp_test - ask kernel whether a given compression method
+ * is acceptable for use.  Returns 1 if the method and parameters
+ * are OK, 0 if the method is known but the parameters are not OK
+ * (e.g. code size should be reduced), or -1 if the method is unknown.
+ */
+int
+ccp_test( int unit, int opt_len,  int for_transmit, u_char *opt_ptr)
+{
+  return 0; /* XXX Currently no compression. */
+}
+
+/*
+ * ccp_flags_set - inform kernel about the current state of CCP.
+ */
+void
+ccp_flags_set(int unit, int isopen, int isup)
+{
+  /* XXX */
+}
+
+/*
+ * ccp_fatal_error - returns 1 if decompression was disabled as a
+ * result of an error detected after decompression of a packet,
+ * 0 otherwise.  This is necessary because of patent nonsense.
+ */
+int
+ccp_fatal_error(int unit)
+{
+  /* XXX */
+  return 0;
+}
+#endif
+
+/*
+ * get_idle_time - return how long the link has been idle.
+ */
+int
+get_idle_time(int u, struct ppp_idle *ip)
+{
+  /* XXX */
+  LWIP_UNUSED_ARG(u);
+  LWIP_UNUSED_ARG(ip);
+
+  return 0;
+}
+
+
+/*
+ * Return user specified netmask, modified by any mask we might determine
+ * for address `addr' (in network byte order).
+ * Here we scan through the system's list of interfaces, looking for
+ * any non-point-to-point interfaces which might appear to be on the same
+ * network as `addr'.  If we find any, we OR in their netmask to the
+ * user-specified netmask.
+ */
+u32_t
+GetMask(u32_t addr)
+{
+  u32_t mask, nmask;
+
+  htonl(addr);
+  if (IP_CLASSA(addr)) { /* determine network mask for address class */
+    nmask = IP_CLASSA_NET;
+  } else if (IP_CLASSB(addr)) {
+    nmask = IP_CLASSB_NET;
+  } else { 
+    nmask = IP_CLASSC_NET;
+  }
+
+  /* class D nets are disallowed by bad_ip_adrs */
+  mask = subnetMask | htonl(nmask);
+  
+  /* XXX
+   * Scan through the system's network interfaces.
+   * Get each netmask and OR them into our mask.
+   */
+
+  return mask;
+}
+
+/*
+ * sifvjcomp - config tcp header compression
+ */
+int
+sifvjcomp(int pd, int vjcomp, u8_t cidcomp, u8_t maxcid)
+{
+#if PPPOS_SUPPORT && VJ_SUPPORT
+  PPPControl *pc = &pppControl[pd];
+  
+  pc->vjEnabled = vjcomp;
+  pc->vjComp.compressSlot = cidcomp;
+  pc->vjComp.maxSlotIndex = maxcid;
+  PPPDEBUG(LOG_INFO, ("sifvjcomp: VJ compress enable=%d slot=%d max slot=%d\n",
+            vjcomp, cidcomp, maxcid));
+#else /* PPPOS_SUPPORT && VJ_SUPPORT */
+  LWIP_UNUSED_ARG(pd);
+  LWIP_UNUSED_ARG(vjcomp);
+  LWIP_UNUSED_ARG(cidcomp);
+  LWIP_UNUSED_ARG(maxcid);
+#endif /* PPPOS_SUPPORT && VJ_SUPPORT */
+
+  return 0;
+}
+
+/*
+ * pppifNetifInit - netif init callback
+ */
+static err_t
+pppifNetifInit(struct netif *netif)
+{
+  netif->name[0] = 'p';
+  netif->name[1] = 'p';
+  netif->output = pppifOutput;
+  netif->mtu = pppMTU((int)(size_t)netif->state);
+  netif->flags = NETIF_FLAG_POINTTOPOINT | NETIF_FLAG_LINK_UP;
+#if LWIP_NETIF_HOSTNAME
+  /* @todo: Initialize interface hostname */
+  /* netif_set_hostname(netif, "lwip"); */
+#endif /* LWIP_NETIF_HOSTNAME */
+  return ERR_OK;
+}
+
+
+/*
+ * sifup - Config the interface up and enable IP packets to pass.
+ */
+int
+sifup(int pd)
+{
+  PPPControl *pc = &pppControl[pd];
+  int st = 1;
+  
+  if (pd < 0 || pd >= NUM_PPP || !pc->openFlag) {
+    st = 0;
+    PPPDEBUG(LOG_WARNING, ("sifup[%d]: bad parms\n", pd));
+  } else {
+    netif_remove(&pc->netif);
+    if (netif_add(&pc->netif, &pc->addrs.our_ipaddr, &pc->addrs.netmask,
+                  &pc->addrs.his_ipaddr, (void *)(size_t)pd, pppifNetifInit, ip_input)) {
+      netif_set_up(&pc->netif);
+      pc->if_up = 1;
+      pc->errCode = PPPERR_NONE;
+
+      PPPDEBUG(LOG_DEBUG, ("sifup: unit %d: linkStatusCB=%p errCode=%d\n", pd, pc->linkStatusCB, pc->errCode));
+      if (pc->linkStatusCB) {
+        pc->linkStatusCB(pc->linkStatusCtx, pc->errCode, &pc->addrs);
+      }
+    } else {
+      st = 0;
+      PPPDEBUG(LOG_ERR, ("sifup[%d]: netif_add failed\n", pd));
+    }
+  }
+
+  return st;
+}
+
+/*
+ * sifnpmode - Set the mode for handling packets for a given NP.
+ */
+int
+sifnpmode(int u, int proto, enum NPmode mode)
+{
+  LWIP_UNUSED_ARG(u);
+  LWIP_UNUSED_ARG(proto);
+  LWIP_UNUSED_ARG(mode);
+  return 0;
+}
+
+/*
+ * sifdown - Config the interface down and disable IP.
+ */
+int
+sifdown(int pd)
+{
+  PPPControl *pc = &pppControl[pd];
+  int st = 1;
+  
+  if (pd < 0 || pd >= NUM_PPP || !pc->openFlag) {
+    st = 0;
+    PPPDEBUG(LOG_WARNING, ("sifdown[%d]: bad parms\n", pd));
+  } else {
+    pc->if_up = 0;
+    /* make sure the netif status callback is called */
+    netif_set_down(&pc->netif);
+    netif_remove(&pc->netif);
+    PPPDEBUG(LOG_DEBUG, ("sifdown: unit %d: linkStatusCB=%p errCode=%d\n", pd, pc->linkStatusCB, pc->errCode));
+    if (pc->linkStatusCB) {
+      pc->linkStatusCB(pc->linkStatusCtx, PPPERR_CONNECT, NULL);
+    }
+  }
+  return st;
+}
+
+/**
+ * sifaddr - Config the interface IP addresses and netmask.
+ * @param pd Interface unit ???
+ * @param o Our IP address ???
+ * @param h His IP address ???
+ * @param m IP subnet mask ???
+ * @param ns1 Primary DNS
+ * @param ns2 Secondary DNS
+ */
+int
+sifaddr( int pd, u32_t o, u32_t h, u32_t m, u32_t ns1, u32_t ns2)
+{
+  PPPControl *pc = &pppControl[pd];
+  int st = 1;
+  
+  if (pd < 0 || pd >= NUM_PPP || !pc->openFlag) {
+    st = 0;
+    PPPDEBUG(LOG_WARNING, ("sifup[%d]: bad parms\n", pd));
+  } else {
+    SMEMCPY(&pc->addrs.our_ipaddr, &o, sizeof(o));
+    SMEMCPY(&pc->addrs.his_ipaddr, &h, sizeof(h));
+    SMEMCPY(&pc->addrs.netmask, &m, sizeof(m));
+    SMEMCPY(&pc->addrs.dns1, &ns1, sizeof(ns1));
+    SMEMCPY(&pc->addrs.dns2, &ns2, sizeof(ns2));
+  }
+  return st;
+}
+
+/**
+ * cifaddr - Clear the interface IP addresses, and delete routes
+ * through the interface if possible.
+ * @param pd Interface unit ???
+ * @param o Our IP address ???
+ * @param h IP broadcast address ???
+ */
+int
+cifaddr( int pd, u32_t o, u32_t h)
+{
+  PPPControl *pc = &pppControl[pd];
+  int st = 1;
+  
+  LWIP_UNUSED_ARG(o);
+  LWIP_UNUSED_ARG(h);
+  if (pd < 0 || pd >= NUM_PPP || !pc->openFlag) {
+    st = 0;
+    PPPDEBUG(LOG_WARNING, ("sifup[%d]: bad parms\n", pd));
+  } else {
+    IP4_ADDR(&pc->addrs.our_ipaddr, 0,0,0,0);
+    IP4_ADDR(&pc->addrs.his_ipaddr, 0,0,0,0);
+    IP4_ADDR(&pc->addrs.netmask, 255,255,255,0);
+    IP4_ADDR(&pc->addrs.dns1, 0,0,0,0);
+    IP4_ADDR(&pc->addrs.dns2, 0,0,0,0);
+  }
+  return st;
+}
+
+/*
+ * sifdefaultroute - assign a default route through the address given.
+ */
+int
+sifdefaultroute(int pd, u32_t l, u32_t g)
+{
+  PPPControl *pc = &pppControl[pd];
+  int st = 1;
+
+  LWIP_UNUSED_ARG(l);
+  LWIP_UNUSED_ARG(g);
+
+  if (pd < 0 || pd >= NUM_PPP || !pc->openFlag) {
+    st = 0;
+    PPPDEBUG(LOG_WARNING, ("sifup[%d]: bad parms\n", pd));
+  } else {
+    netif_set_default(&pc->netif);
+  }
+
+  /* TODO: check how PPP handled the netMask, previously not set by ipSetDefault */
+
+  return st;
+}
+
+/*
+ * cifdefaultroute - delete a default route through the address given.
+ */
+int
+cifdefaultroute(int pd, u32_t l, u32_t g)
+{
+  PPPControl *pc = &pppControl[pd];
+  int st = 1;
+
+  LWIP_UNUSED_ARG(l);
+  LWIP_UNUSED_ARG(g);
+
+  if (pd < 0 || pd >= NUM_PPP || !pc->openFlag) {
+    st = 0;
+    PPPDEBUG(LOG_WARNING, ("sifup[%d]: bad parms\n", pd));
+  } else {
+    netif_set_default(NULL);
+  }
+
+  return st;
+}
+
+/**********************************/
+/*** LOCAL FUNCTION DEFINITIONS ***/
+/**********************************/
+
+#if PPPOS_SUPPORT && PPP_INPROC_OWNTHREAD
+/* The main PPP process function.  This implements the state machine according
+ * to section 4 of RFC 1661: The Point-To-Point Protocol. */
+static void
+pppInputThread(void *arg)
+{
+  int count;
+  PPPControlRx *pcrx = arg;
+
+  while (lcp_phase[pcrx->pd] != PHASE_DEAD) {
+    count = sio_read(pcrx->fd, pcrx->rxbuf, PPPOS_RX_BUFSIZE);
+    if(count > 0) {
+      pppInProc(pcrx, pcrx->rxbuf, count);
+    } else {
+      /* nothing received, give other tasks a chance to run */
+      sys_msleep(1);
+    }
+  }
+}
+#endif /* PPPOS_SUPPORT && PPP_INPROC_OWNTHREAD */
+
+#if PPPOE_SUPPORT
+
+void
+pppOverEthernetInitFailed(int pd)
+{
+  PPPControl* pc;
+
+  pppHup(pd);
+  pppStop(pd);
+
+  pc = &pppControl[pd];
+  pppoe_destroy(&pc->netif);
+  pc->openFlag = 0;
+
+  if(pc->linkStatusCB) {
+    pc->linkStatusCB(pc->linkStatusCtx, pc->errCode ? pc->errCode : PPPERR_PROTOCOL, NULL);
+  }
+}
+
+static void
+pppOverEthernetLinkStatusCB(int pd, int up)
+{
+  if(up) {
+    PPPDEBUG(LOG_INFO, ("pppOverEthernetLinkStatusCB: unit %d: Connecting\n", pd));
+    pppStart(pd);
+  } else {
+    pppOverEthernetInitFailed(pd);
+  }
+}
+#endif /* PPPOE_SUPPORT */
+
+struct pbuf *
+pppSingleBuf(struct pbuf *p)
+{
+  struct pbuf *q, *b;
+  u_char *pl;
+
+  if(p->tot_len == p->len) {
+    return p;
+  }
+
+  q = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_RAM);
+  if(!q) {
+    PPPDEBUG(LOG_ERR,
+             ("pppSingleBuf: unable to alloc new buf (%d)\n", p->tot_len));
+    return p; /* live dangerously */
+  }
+
+  for(b = p, pl = q->payload; b != NULL; b = b->next) {
+    MEMCPY(pl, b->payload, b->len);
+    pl += b->len;
+  }
+
+  pbuf_free(p);
+
+  return q;
+}
+
+struct pppInputHeader {
+  int unit;
+  u16_t proto;
+};
+
+/*
+ * Pass the processed input packet to the appropriate handler.
+ * This function and all handlers run in the context of the tcpip_thread
+ */
+static void
+pppInput(void *arg)
+{
+  struct pbuf *nb = (struct pbuf *)arg;
+  u16_t protocol;
+  int pd;
+
+  pd = ((struct pppInputHeader *)nb->payload)->unit;
+  protocol = ((struct pppInputHeader *)nb->payload)->proto;
+    
+  if(pbuf_header(nb, -(int)sizeof(struct pppInputHeader))) {
+    LWIP_ASSERT("pbuf_header failed\n", 0);
+    goto drop;
+  }
+
+  LINK_STATS_INC(link.recv);
+  snmp_inc_ifinucastpkts(&pppControl[pd].netif);
+  snmp_add_ifinoctets(&pppControl[pd].netif, nb->tot_len);
+
+  /*
+   * Toss all non-LCP packets unless LCP is OPEN.
+   * Until we get past the authentication phase, toss all packets
+   * except LCP, LQR and authentication packets.
+   */
+  if((lcp_phase[pd] <= PHASE_AUTHENTICATE) && (protocol != PPP_LCP)) {
+    if(!((protocol == PPP_LQR) || (protocol == PPP_PAP) || (protocol == PPP_CHAP)) ||
+        (lcp_phase[pd] != PHASE_AUTHENTICATE)) {
+      PPPDEBUG(LOG_INFO, ("pppInput: discarding proto 0x%"X16_F" in phase %d\n", protocol, lcp_phase[pd]));
+      goto drop;
+    }
+  }
+
+  switch(protocol) {
+    case PPP_VJC_COMP:      /* VJ compressed TCP */
+#if PPPOS_SUPPORT && VJ_SUPPORT
+      PPPDEBUG(LOG_INFO, ("pppInput[%d]: vj_comp in pbuf len=%d\n", pd, nb->len));
+      /*
+       * Clip off the VJ header and prepend the rebuilt TCP/IP header and
+       * pass the result to IP.
+       */
+      if ((vj_uncompress_tcp(&nb, &pppControl[pd].vjComp) >= 0) && (pppControl[pd].netif.input)) {
+        pppControl[pd].netif.input(nb, &pppControl[pd].netif);
+        return;
+      }
+      /* Something's wrong so drop it. */
+      PPPDEBUG(LOG_WARNING, ("pppInput[%d]: Dropping VJ compressed\n", pd));
+#else  /* PPPOS_SUPPORT && VJ_SUPPORT */
+      /* No handler for this protocol so drop the packet. */
+      PPPDEBUG(LOG_INFO, ("pppInput[%d]: drop VJ Comp in %d:%s\n", pd, nb->len, nb->payload));
+#endif /* PPPOS_SUPPORT && VJ_SUPPORT */
+      break;
+
+    case PPP_VJC_UNCOMP:    /* VJ uncompressed TCP */
+#if PPPOS_SUPPORT && VJ_SUPPORT
+      PPPDEBUG(LOG_INFO, ("pppInput[%d]: vj_un in pbuf len=%d\n", pd, nb->len));
+      /*
+       * Process the TCP/IP header for VJ header compression and then pass
+       * the packet to IP.
+       */
+      if ((vj_uncompress_uncomp(nb, &pppControl[pd].vjComp) >= 0) && pppControl[pd].netif.input) {
+        pppControl[pd].netif.input(nb, &pppControl[pd].netif);
+        return;
+      }
+      /* Something's wrong so drop it. */
+      PPPDEBUG(LOG_WARNING, ("pppInput[%d]: Dropping VJ uncompressed\n", pd));
+#else  /* PPPOS_SUPPORT && VJ_SUPPORT */
+      /* No handler for this protocol so drop the packet. */
+      PPPDEBUG(LOG_INFO,
+               ("pppInput[%d]: drop VJ UnComp in %d:.*H\n", 
+                pd, nb->len, LWIP_MIN(nb->len * 2, 40), nb->payload));
+#endif /* PPPOS_SUPPORT && VJ_SUPPORT */
+      break;
+
+    case PPP_IP:            /* Internet Protocol */
+      PPPDEBUG(LOG_INFO, ("pppInput[%d]: ip in pbuf len=%d\n", pd, nb->len));
+      if (pppControl[pd].netif.input) {
+        pppControl[pd].netif.input(nb, &pppControl[pd].netif);
+        return;
+      }
+      break;
+
+    default: {
+      struct protent *protp;
+      int i;
+
+      /*
+       * Upcall the proper protocol input routine.
+       */
+      for (i = 0; (protp = ppp_protocols[i]) != NULL; ++i) {
+        if (protp->protocol == protocol && protp->enabled_flag) {
+          PPPDEBUG(LOG_INFO, ("pppInput[%d]: %s len=%d\n", pd, protp->name, nb->len));
+          nb = pppSingleBuf(nb);
+          (*protp->input)(pd, nb->payload, nb->len);
+          PPPDEBUG(LOG_DETAIL, ("pppInput[%d]: packet processed\n", pd));
+          goto out;
+        }
+      }
+
+      /* No handler for this protocol so reject the packet. */
+      PPPDEBUG(LOG_INFO, ("pppInput[%d]: rejecting unsupported proto 0x%"X16_F" len=%d\n", pd, protocol, nb->len));
+      if (pbuf_header(nb, sizeof(protocol))) {
+        LWIP_ASSERT("pbuf_header failed\n", 0);
+        goto drop;
+      }
+#if BYTE_ORDER == LITTLE_ENDIAN
+      protocol = htons(protocol);
+#endif /* BYTE_ORDER == LITTLE_ENDIAN */
+      SMEMCPY(nb->payload, &protocol, sizeof(protocol));
+      lcp_sprotrej(pd, nb->payload, nb->len);
+    }
+    break;
+  }
+
+drop:
+  LINK_STATS_INC(link.drop);
+  snmp_inc_ifindiscards(&pppControl[pd].netif);
+
+out:
+  pbuf_free(nb);
+  return;
+}
+
+#if PPPOS_SUPPORT
+/*
+ * Drop the input packet.
+ */
+static void
+pppDrop(PPPControlRx *pcrx)
+{
+  if (pcrx->inHead != NULL) {
+#if 0
+    PPPDEBUG(LOG_INFO, ("pppDrop: %d:%.*H\n", pcrx->inHead->len, min(60, pcrx->inHead->len * 2), pcrx->inHead->payload));
+#endif
+    PPPDEBUG(LOG_INFO, ("pppDrop: pbuf len=%d, addr %p\n", pcrx->inHead->len, (void*)pcrx->inHead));
+    if (pcrx->inTail && (pcrx->inTail != pcrx->inHead)) {
+      pbuf_free(pcrx->inTail);
+    }
+    pbuf_free(pcrx->inHead);
+    pcrx->inHead = NULL;
+    pcrx->inTail = NULL;
+  }
+#if VJ_SUPPORT
+  vj_uncompress_err(&pppControl[pcrx->pd].vjComp);
+#endif /* VJ_SUPPORT */
+
+  LINK_STATS_INC(link.drop);
+  snmp_inc_ifindiscards(&pppControl[pcrx->pd].netif);
+}
+
+/** Pass received raw characters to PPPoS to be decoded. This function is
+ * thread-safe and can be called from a dedicated RX-thread or from a main-loop.
+ *
+ * @param pd PPP descriptor index, returned by pppOpen()
+ * @param data received data
+ * @param len length of received data
+ */
+void
+pppos_input(int pd, u_char* data, int len)
+{
+  pppInProc(&pppControl[pd].rx, data, len);
+}
+
+/**
+ * Process a received octet string.
+ */
+static void
+pppInProc(PPPControlRx *pcrx, u_char *s, int l)
+{
+  struct pbuf *nextNBuf;
+  u_char curChar;
+  u_char escaped;
+  SYS_ARCH_DECL_PROTECT(lev);
+
+  PPPDEBUG(LOG_DEBUG, ("pppInProc[%d]: got %d bytes\n", pcrx->pd, l));
+  while (l-- > 0) {
+    curChar = *s++;
+
+    SYS_ARCH_PROTECT(lev);
+    escaped = ESCAPE_P(pcrx->inACCM, curChar);
+    SYS_ARCH_UNPROTECT(lev);
+    /* Handle special characters. */
+    if (escaped) {
+      /* Check for escape sequences. */
+      /* XXX Note that this does not handle an escaped 0x5d character which
+       * would appear as an escape character.  Since this is an ASCII ']'
+       * and there is no reason that I know of to escape it, I won't complicate
+       * the code to handle this case. GLL */
+      if (curChar == PPP_ESCAPE) {
+        pcrx->inEscaped = 1;
+      /* Check for the flag character. */
+      } else if (curChar == PPP_FLAG) {
+        /* If this is just an extra flag character, ignore it. */
+        if (pcrx->inState <= PDADDRESS) {
+          /* ignore it */;
+        /* If we haven't received the packet header, drop what has come in. */
+        } else if (pcrx->inState < PDDATA) {
+          PPPDEBUG(LOG_WARNING,
+                   ("pppInProc[%d]: Dropping incomplete packet %d\n", 
+                    pcrx->pd, pcrx->inState));
+          LINK_STATS_INC(link.lenerr);
+          pppDrop(pcrx);
+        /* If the fcs is invalid, drop the packet. */
+        } else if (pcrx->inFCS != PPP_GOODFCS) {
+          PPPDEBUG(LOG_INFO,
+                   ("pppInProc[%d]: Dropping bad fcs 0x%"X16_F" proto=0x%"X16_F"\n", 
+                    pcrx->pd, pcrx->inFCS, pcrx->inProtocol));
+          /* Note: If you get lots of these, check for UART frame errors or try different baud rate */
+          LINK_STATS_INC(link.chkerr);
+          pppDrop(pcrx);
+        /* Otherwise it's a good packet so pass it on. */
+        } else {
+          struct pbuf *inp;
+          /* Trim off the checksum. */
+          if(pcrx->inTail->len >= 2) {
+            pcrx->inTail->len -= 2;
+
+            pcrx->inTail->tot_len = pcrx->inTail->len;
+            if (pcrx->inTail != pcrx->inHead) {
+              pbuf_cat(pcrx->inHead, pcrx->inTail);
+            }
+          } else {
+            pcrx->inTail->tot_len = pcrx->inTail->len;
+            if (pcrx->inTail != pcrx->inHead) {
+              pbuf_cat(pcrx->inHead, pcrx->inTail);
+            }
+
+            pbuf_realloc(pcrx->inHead, pcrx->inHead->tot_len - 2);
+          }
+
+          /* Dispatch the packet thereby consuming it. */
+          inp = pcrx->inHead;
+          /* Packet consumed, release our references. */
+          pcrx->inHead = NULL;
+          pcrx->inTail = NULL;
+#if PPP_INPROC_MULTITHREADED
+          if(tcpip_callback_with_block(pppInput, inp, 0) != ERR_OK) {
+            PPPDEBUG(LOG_ERR, ("pppInProc[%d]: tcpip_callback() failed, dropping packet\n", pcrx->pd));
+            pbuf_free(inp);
+            LINK_STATS_INC(link.drop);
+            snmp_inc_ifindiscards(&pppControl[pcrx->pd].netif);
+          }
+#else /* PPP_INPROC_MULTITHREADED */
+          pppInput(inp);
+#endif /* PPP_INPROC_MULTITHREADED */
+        }
+
+        /* Prepare for a new packet. */
+        pcrx->inFCS = PPP_INITFCS;
+        pcrx->inState = PDADDRESS;
+        pcrx->inEscaped = 0;
+      /* Other characters are usually control characters that may have
+       * been inserted by the physical layer so here we just drop them. */
+      } else {
+        PPPDEBUG(LOG_WARNING,
+                 ("pppInProc[%d]: Dropping ACCM char <%d>\n", pcrx->pd, curChar));
+      }
+    /* Process other characters. */
+    } else {
+      /* Unencode escaped characters. */
+      if (pcrx->inEscaped) {
+        pcrx->inEscaped = 0;
+        curChar ^= PPP_TRANS;
+      }
+
+      /* Process character relative to current state. */
+      switch(pcrx->inState) {
+        case PDIDLE:                    /* Idle state - waiting. */
+          /* Drop the character if it's not 0xff
+           * we would have processed a flag character above. */
+          if (curChar != PPP_ALLSTATIONS) {
+            break;
+          }
+
+        /* Fall through */
+        case PDSTART:                   /* Process start flag. */
+          /* Prepare for a new packet. */
+          pcrx->inFCS = PPP_INITFCS;
+
+        /* Fall through */
+        case PDADDRESS:                 /* Process address field. */
+          if (curChar == PPP_ALLSTATIONS) {
+            pcrx->inState = PDCONTROL;
+            break;
+          }
+          /* Else assume compressed address and control fields so
+           * fall through to get the protocol... */
+        case PDCONTROL:                 /* Process control field. */
+          /* If we don't get a valid control code, restart. */
+          if (curChar == PPP_UI) {
+            pcrx->inState = PDPROTOCOL1;
+            break;
+          }
+#if 0
+          else {
+            PPPDEBUG(LOG_WARNING,
+                     ("pppInProc[%d]: Invalid control <%d>\n", pcrx->pd, curChar));
+            pcrx->inState = PDSTART;
+          }
+#endif
+        case PDPROTOCOL1:               /* Process protocol field 1. */
+          /* If the lower bit is set, this is the end of the protocol
+           * field. */
+          if (curChar & 1) {
+            pcrx->inProtocol = curChar;
+            pcrx->inState = PDDATA;
+          } else {
+            pcrx->inProtocol = (u_int)curChar << 8;
+            pcrx->inState = PDPROTOCOL2;
+          }
+          break;
+        case PDPROTOCOL2:               /* Process protocol field 2. */
+          pcrx->inProtocol |= curChar;
+          pcrx->inState = PDDATA;
+          break;
+        case PDDATA:                    /* Process data byte. */
+          /* Make space to receive processed data. */
+          if (pcrx->inTail == NULL || pcrx->inTail->len == PBUF_POOL_BUFSIZE) {
+            if (pcrx->inTail != NULL) {
+              pcrx->inTail->tot_len = pcrx->inTail->len;
+              if (pcrx->inTail != pcrx->inHead) {
+                pbuf_cat(pcrx->inHead, pcrx->inTail);
+                /* give up the inTail reference now */
+                pcrx->inTail = NULL;
+              }
+            }
+            /* If we haven't started a packet, we need a packet header. */
+            nextNBuf = pbuf_alloc(PBUF_RAW, 0, PBUF_POOL);
+            if (nextNBuf == NULL) {
+              /* No free buffers.  Drop the input packet and let the
+               * higher layers deal with it.  Continue processing
+               * the received pbuf chain in case a new packet starts. */
+              PPPDEBUG(LOG_ERR, ("pppInProc[%d]: NO FREE MBUFS!\n", pcrx->pd));
+              LINK_STATS_INC(link.memerr);
+              pppDrop(pcrx);
+              pcrx->inState = PDSTART;  /* Wait for flag sequence. */
+              break;
+            }
+            if (pcrx->inHead == NULL) {
+              struct pppInputHeader *pih = nextNBuf->payload;
+
+              pih->unit = pcrx->pd;
+              pih->proto = pcrx->inProtocol;
+
+              nextNBuf->len += sizeof(*pih);
+
+              pcrx->inHead = nextNBuf;
+            }
+            pcrx->inTail = nextNBuf;
+          }
+          /* Load character into buffer. */
+          ((u_char*)pcrx->inTail->payload)[pcrx->inTail->len++] = curChar;
+          break;
+      }
+
+      /* update the frame check sequence number. */
+      pcrx->inFCS = PPP_FCS(pcrx->inFCS, curChar);
+    }
+  } /* while (l-- > 0), all bytes processed */
+
+  avRandomize();
+}
+#endif /* PPPOS_SUPPORT */
+
+#if PPPOE_SUPPORT
+void
+pppInProcOverEthernet(int pd, struct pbuf *pb)
+{
+  struct pppInputHeader *pih;
+  u16_t inProtocol;
+
+  if(pb->len < sizeof(inProtocol)) {
+    PPPDEBUG(LOG_ERR, ("pppInProcOverEthernet: too small for protocol field\n"));
+    goto drop;
+  }
+
+  inProtocol = (((u8_t *)pb->payload)[0] << 8) | ((u8_t*)pb->payload)[1];
+
+  /* make room for pppInputHeader - should not fail */
+  if (pbuf_header(pb, sizeof(*pih) - sizeof(inProtocol)) != 0) {
+    PPPDEBUG(LOG_ERR, ("pppInProcOverEthernet: could not allocate room for header\n"));
+    goto drop;
+  }
+
+  pih = pb->payload;
+
+  pih->unit = pd;
+  pih->proto = inProtocol;
+
+  /* Dispatch the packet thereby consuming it. */
+  pppInput(pb);
+  return;
+
+drop:
+  LINK_STATS_INC(link.drop);
+  snmp_inc_ifindiscards(&pppControl[pd].netif);
+  pbuf_free(pb);
+  return;
+}
+#endif /* PPPOE_SUPPORT */
+
+#if LWIP_NETIF_STATUS_CALLBACK
+/** Set the status callback of a PPP's netif
+ *
+ * @param pd The PPP descriptor returned by pppOpen()
+ * @param status_callback pointer to the status callback function
+ *
+ * @see netif_set_status_callback
+ */
+void
+ppp_set_netif_statuscallback(int pd, netif_status_callback_fn status_callback)
+{
+  netif_set_status_callback(&pppControl[pd].netif, status_callback); 
+}
+#endif /* LWIP_NETIF_STATUS_CALLBACK */
+
+#if LWIP_NETIF_LINK_CALLBACK
+/** Set the link callback of a PPP's netif
+ *
+ * @param pd The PPP descriptor returned by pppOpen()
+ * @param link_callback pointer to the link callback function
+ *
+ * @see netif_set_link_callback
+ */
+void
+ppp_set_netif_linkcallback(int pd, netif_status_callback_fn link_callback)
+{
+  netif_set_link_callback(&pppControl[pd].netif, link_callback); 
+}
+#endif /* LWIP_NETIF_LINK_CALLBACK */
+
+#endif /* PPP_SUPPORT */
diff --git a/core/lwip/src/netif/ppp/ppp.h b/core/lwip/src/netif/ppp/ppp.h
new file mode 100644
index 00000000..a72ac957
--- /dev/null
+++ b/core/lwip/src/netif/ppp/ppp.h
@@ -0,0 +1,483 @@
+/*****************************************************************************
+* ppp.h - Network Point to Point Protocol header file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* portions Copyright (c) 1997 Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 97-11-05 Guy Lancaster <glanca@gesn.com>, Global Election Systems Inc.
+*   Original derived from BSD codes.
+*****************************************************************************/
+
+#ifndef PPP_H
+#define PPP_H
+
+#include "lwip/opt.h"
+
+#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/def.h"
+#include "lwip/sio.h"
+#include "lwip/stats.h"
+#include "lwip/mem.h"
+#include "lwip/netif.h"
+#include "lwip/sys.h"
+#include "lwip/timers.h"
+
+/** Some defines for code we skip compared to the original pppd.
+ *  These are just here to minimise the use of the ugly "#if 0". */
+#define PPP_ADDITIONAL_CALLBACKS  0
+
+/** Some error checks to test for unsupported code */
+#if CBCP_SUPPORT
+#error "CBCP is not supported in lwIP PPP"
+#endif
+#if CCP_SUPPORT
+#error "CCP is not supported in lwIP PPP"
+#endif
+
+/*
+ * pppd.h - PPP daemon global declarations.
+ *
+ * Copyright (c) 1989 Carnegie Mellon University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Carnegie Mellon University.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+/*
+ * ppp_defs.h - PPP definitions.
+ *
+ * Copyright (c) 1994 The Australian National University.
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify, and distribute this software and its
+ * documentation is hereby granted, provided that the above copyright
+ * notice appears in all copies.  This software is provided without any
+ * warranty, express or implied. The Australian National University
+ * makes no representations about the suitability of this software for
+ * any purpose.
+ *
+ * IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY
+ * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
+ * THE AUSTRALIAN NATIONAL UNIVERSITY HAVE BEEN ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO
+ * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
+ * OR MODIFICATIONS.
+ */
+
+#define TIMEOUT(f, a, t)    do { sys_untimeout((f), (a)); sys_timeout((t)*1000, (f), (a)); } while(0)
+#define UNTIMEOUT(f, a)     sys_untimeout((f), (a))
+
+
+#ifndef __u_char_defined
+
+/* Type definitions for BSD code. */
+typedef unsigned long  u_long;
+typedef unsigned int   u_int;
+typedef unsigned short u_short;
+typedef unsigned char  u_char;
+
+#endif
+
+/*
+ * Constants and structures defined by the internet system,
+ * Per RFC 790, September 1981, and numerous additions.
+ */
+
+/*
+ * The basic PPP frame.
+ */
+#define PPP_HDRLEN      4       /* octets for standard ppp header */
+#define PPP_FCSLEN      2       /* octets for FCS */
+
+
+/*
+ * Significant octet values.
+ */
+#define PPP_ALLSTATIONS 0xff    /* All-Stations broadcast address */
+#define PPP_UI          0x03    /* Unnumbered Information */
+#define PPP_FLAG        0x7e    /* Flag Sequence */
+#define PPP_ESCAPE      0x7d    /* Asynchronous Control Escape */
+#define PPP_TRANS       0x20    /* Asynchronous transparency modifier */
+
+/*
+ * Protocol field values.
+ */
+#define PPP_IP          0x21    /* Internet Protocol */
+#define PPP_AT          0x29    /* AppleTalk Protocol */
+#define PPP_VJC_COMP    0x2d    /* VJ compressed TCP */
+#define PPP_VJC_UNCOMP  0x2f    /* VJ uncompressed TCP */
+#define PPP_COMP        0xfd    /* compressed packet */
+#define PPP_IPCP        0x8021  /* IP Control Protocol */
+#define PPP_ATCP        0x8029  /* AppleTalk Control Protocol */
+#define PPP_CCP         0x80fd  /* Compression Control Protocol */
+#define PPP_LCP         0xc021  /* Link Control Protocol */
+#define PPP_PAP         0xc023  /* Password Authentication Protocol */
+#define PPP_LQR         0xc025  /* Link Quality Report protocol */
+#define PPP_CHAP        0xc223  /* Cryptographic Handshake Auth. Protocol */
+#define PPP_CBCP        0xc029  /* Callback Control Protocol */
+
+/*
+ * Values for FCS calculations.
+ */
+#define PPP_INITFCS     0xffff  /* Initial FCS value */
+#define PPP_GOODFCS     0xf0b8  /* Good final FCS value */
+#define PPP_FCS(fcs, c) (((fcs) >> 8) ^ fcstab[((fcs) ^ (c)) & 0xff])
+
+/*
+ * Extended asyncmap - allows any character to be escaped.
+ */
+typedef u_char  ext_accm[32];
+
+/*
+ * What to do with network protocol (NP) packets.
+ */
+enum NPmode {
+  NPMODE_PASS,        /* pass the packet through */
+  NPMODE_DROP,        /* silently drop the packet */
+  NPMODE_ERROR,       /* return an error */
+  NPMODE_QUEUE        /* save it up for later. */
+};
+
+/*
+ * Inline versions of get/put char/short/long.
+ * Pointer is advanced; we assume that both arguments
+ * are lvalues and will already be in registers.
+ * cp MUST be u_char *.
+ */
+#define GETCHAR(c, cp) { \
+    (c) = *(cp)++; \
+}
+#define PUTCHAR(c, cp) { \
+    *(cp)++ = (u_char) (c); \
+}
+
+
+#define GETSHORT(s, cp) { \
+    (s) = *(cp); (cp)++; (s) <<= 8; \
+    (s) |= *(cp); (cp)++; \
+}
+#define PUTSHORT(s, cp) { \
+    *(cp)++ = (u_char) ((s) >> 8); \
+    *(cp)++ = (u_char) (s & 0xff); \
+}
+
+#define GETLONG(l, cp) { \
+    (l) = *(cp); (cp)++; (l) <<= 8; \
+    (l) |= *(cp); (cp)++; (l) <<= 8; \
+    (l) |= *(cp); (cp)++; (l) <<= 8; \
+    (l) |= *(cp); (cp)++; \
+}
+#define PUTLONG(l, cp) { \
+    *(cp)++ = (u_char) ((l) >> 24); \
+    *(cp)++ = (u_char) ((l) >> 16); \
+    *(cp)++ = (u_char) ((l) >> 8); \
+    *(cp)++ = (u_char) (l); \
+}
+
+
+#define INCPTR(n, cp)   ((cp) += (n))
+#define DECPTR(n, cp)   ((cp) -= (n))
+
+#define BCMP(s0, s1, l)     memcmp((u_char *)(s0), (u_char *)(s1), (l))
+#define BCOPY(s, d, l)      MEMCPY((d), (s), (l))
+#define BZERO(s, n)         memset(s, 0, n)
+
+#if PPP_DEBUG
+#define PRINTMSG(m, l)  { m[l] = '\0'; LWIP_DEBUGF(LOG_INFO, ("Remote message: %s\n", m)); }
+#else  /* PPP_DEBUG */
+#define PRINTMSG(m, l)
+#endif /* PPP_DEBUG */
+
+/*
+ * MAKEHEADER - Add PPP Header fields to a packet.
+ */
+#define MAKEHEADER(p, t) { \
+    PUTCHAR(PPP_ALLSTATIONS, p); \
+    PUTCHAR(PPP_UI, p); \
+    PUTSHORT(t, p); }
+
+/*************************
+*** PUBLIC DEFINITIONS ***
+*************************/
+
+/* Error codes. */
+#define PPPERR_NONE      0 /* No error. */
+#define PPPERR_PARAM    -1 /* Invalid parameter. */
+#define PPPERR_OPEN     -2 /* Unable to open PPP session. */
+#define PPPERR_DEVICE   -3 /* Invalid I/O device for PPP. */
+#define PPPERR_ALLOC    -4 /* Unable to allocate resources. */
+#define PPPERR_USER     -5 /* User interrupt. */
+#define PPPERR_CONNECT  -6 /* Connection lost. */
+#define PPPERR_AUTHFAIL -7 /* Failed authentication challenge. */
+#define PPPERR_PROTOCOL -8 /* Failed to meet protocol. */
+
+/*
+ * PPP IOCTL commands.
+ */
+/*
+ * Get the up status - 0 for down, non-zero for up.  The argument must
+ * point to an int.
+ */
+#define PPPCTLG_UPSTATUS 100 /* Get the up status - 0 down else up */
+#define PPPCTLS_ERRCODE  101 /* Set the error code */
+#define PPPCTLG_ERRCODE  102 /* Get the error code */
+#define PPPCTLG_FD       103 /* Get the fd associated with the ppp */
+
+/************************
+*** PUBLIC DATA TYPES ***
+************************/
+
+/*
+ * The following struct gives the addresses of procedures to call
+ * for a particular protocol.
+ */
+struct protent {
+    u_short protocol;       /* PPP protocol number */
+    /* Initialization procedure */
+    void (*init) (int unit);
+    /* Process a received packet */
+    void (*input) (int unit, u_char *pkt, int len);
+    /* Process a received protocol-reject */
+    void (*protrej) (int unit);
+    /* Lower layer has come up */
+    void (*lowerup) (int unit);
+    /* Lower layer has gone down */
+    void (*lowerdown) (int unit);
+    /* Open the protocol */
+    void (*open) (int unit);
+    /* Close the protocol */
+    void (*close) (int unit, char *reason);
+#if PPP_ADDITIONAL_CALLBACKS
+    /* Print a packet in readable form */
+    int  (*printpkt) (u_char *pkt, int len,
+              void (*printer) (void *, char *, ...),
+              void *arg);
+    /* Process a received data packet */
+    void (*datainput) (int unit, u_char *pkt, int len);
+#endif /* PPP_ADDITIONAL_CALLBACKS */
+    int  enabled_flag;      /* 0 if protocol is disabled */
+    char *name;         /* Text name of protocol */
+#if PPP_ADDITIONAL_CALLBACKS
+    /* Check requested options, assign defaults */
+    void (*check_options) (u_long);
+    /* Configure interface for demand-dial */
+    int  (*demand_conf) (int unit);
+    /* Say whether to bring up link for this pkt */
+    int  (*active_pkt) (u_char *pkt, int len);
+#endif /* PPP_ADDITIONAL_CALLBACKS */
+};
+
+/*
+ * The following structure records the time in seconds since
+ * the last NP packet was sent or received.
+ */
+struct ppp_idle {
+  u_short xmit_idle;      /* seconds since last NP packet sent */
+  u_short recv_idle;      /* seconds since last NP packet received */
+};
+
+struct ppp_settings {
+
+  u_int  disable_defaultip : 1;       /* Don't use hostname for default IP addrs */
+  u_int  auth_required     : 1;       /* Peer is required to authenticate */
+  u_int  explicit_remote   : 1;       /* remote_name specified with remotename opt */
+  u_int  refuse_pap        : 1;       /* Don't wanna auth. ourselves with PAP */
+  u_int  refuse_chap       : 1;       /* Don't wanna auth. ourselves with CHAP */
+  u_int  usehostname       : 1;       /* Use hostname for our_name */
+  u_int  usepeerdns        : 1;       /* Ask peer for DNS adds */
+
+  u_short idle_time_limit;            /* Shut down link if idle for this long */
+  int  maxconnect;                    /* Maximum connect time (seconds) */
+
+  char user       [MAXNAMELEN   + 1]; /* Username for PAP */
+  char passwd     [MAXSECRETLEN + 1]; /* Password for PAP, secret for CHAP */
+  char our_name   [MAXNAMELEN   + 1]; /* Our name for authentication purposes */
+  char remote_name[MAXNAMELEN   + 1]; /* Peer's name for authentication */
+};
+
+struct ppp_addrs {
+  ip_addr_t our_ipaddr, his_ipaddr, netmask, dns1, dns2;
+};
+
+/*****************************
+*** PUBLIC DATA STRUCTURES ***
+*****************************/
+
+/* Buffers for outgoing packets. */
+extern u_char outpacket_buf[NUM_PPP][PPP_MRU+PPP_HDRLEN];
+
+extern struct ppp_settings ppp_settings;
+
+extern struct protent *ppp_protocols[]; /* Table of pointers to supported protocols */
+
+
+/***********************
+*** PUBLIC FUNCTIONS ***
+***********************/
+
+/* Initialize the PPP subsystem. */
+void pppInit(void);
+
+/* Warning: Using PPPAUTHTYPE_ANY might have security consequences.
+ * RFC 1994 says:
+ *
+ * In practice, within or associated with each PPP server, there is a
+ * database which associates "user" names with authentication
+ * information ("secrets").  It is not anticipated that a particular
+ * named user would be authenticated by multiple methods.  This would
+ * make the user vulnerable to attacks which negotiate the least secure
+ * method from among a set (such as PAP rather than CHAP).  If the same
+ * secret was used, PAP would reveal the secret to be used later with
+ * CHAP.
+ *
+ * Instead, for each user name there should be an indication of exactly
+ * one method used to authenticate that user name.  If a user needs to
+ * make use of different authentication methods under different
+ * circumstances, then distinct user names SHOULD be employed, each of
+ * which identifies exactly one authentication method.
+ *
+ */
+enum pppAuthType {
+    PPPAUTHTYPE_NONE,
+    PPPAUTHTYPE_ANY,
+    PPPAUTHTYPE_PAP,
+    PPPAUTHTYPE_CHAP
+};
+
+void pppSetAuth(enum pppAuthType authType, const char *user, const char *passwd);
+
+/*
+ * Open a new PPP connection using the given serial I/O device.
+ * This initializes the PPP control block but does not
+ * attempt to negotiate the LCP session.
+ * Return a new PPP connection descriptor on success or
+ * an error code (negative) on failure. 
+ */
+int pppOverSerialOpen(sio_fd_t fd, void (*linkStatusCB)(void *ctx, int errCode, void *arg), void *linkStatusCtx);
+
+/*
+ * Open a new PPP Over Ethernet (PPPOE) connection.
+ */
+int pppOverEthernetOpen(struct netif *ethif, const char *service_name, const char *concentrator_name, void (*linkStatusCB)(void *ctx, int errCode, void *arg), void *linkStatusCtx);
+
+/* for source code compatibility */
+#define pppOpen(fd,cb,ls) pppOverSerialOpen(fd,cb,ls)
+
+/*
+ * Close a PPP connection and release the descriptor. 
+ * Any outstanding packets in the queues are dropped.
+ * Return 0 on success, an error code on failure. 
+ */
+int pppClose(int pd);
+
+/*
+ * Indicate to the PPP process that the line has disconnected.
+ */
+void pppSigHUP(int pd);
+
+/*
+ * Get and set parameters for the given connection.
+ * Return 0 on success, an error code on failure. 
+ */
+int  pppIOCtl(int pd, int cmd, void *arg);
+
+/*
+ * Return the Maximum Transmission Unit for the given PPP connection.
+ */
+u_short pppMTU(int pd);
+
+/*
+ * Write n characters to a ppp link.
+ * RETURN: >= 0 Number of characters written, -1 Failed to write to device.
+ */
+int pppWrite(int pd, const u_char *s, int n);
+
+void pppInProcOverEthernet(int pd, struct pbuf *pb);
+
+struct pbuf *pppSingleBuf(struct pbuf *p);
+
+void pppLinkTerminated(int pd);
+
+void pppLinkDown(int pd);
+
+void pppos_input(int pd, u_char* data, int len);
+
+/* Configure i/f transmit parameters */
+void ppp_send_config (int, u16_t, u32_t, int, int);
+/* Set extended transmit ACCM */
+void ppp_set_xaccm (int, ext_accm *);
+/* Configure i/f receive parameters */
+void ppp_recv_config (int, int, u32_t, int, int);
+/* Find out how long link has been idle */
+int  get_idle_time (int, struct ppp_idle *);
+
+/* Configure VJ TCP header compression */
+int  sifvjcomp (int, int, u8_t, u8_t);
+/* Configure i/f down (for IP) */
+int  sifup (int);
+/* Set mode for handling packets for proto */
+int  sifnpmode (int u, int proto, enum NPmode mode);
+/* Configure i/f down (for IP) */
+int  sifdown (int);
+/* Configure IP addresses for i/f */
+int  sifaddr (int, u32_t, u32_t, u32_t, u32_t, u32_t);
+/* Reset i/f IP addresses */
+int  cifaddr (int, u32_t, u32_t);
+/* Create default route through i/f */
+int  sifdefaultroute (int, u32_t, u32_t);
+/* Delete default route through i/f */
+int  cifdefaultroute (int, u32_t, u32_t);
+
+/* Get appropriate netmask for address */
+u32_t GetMask (u32_t); 
+
+#if LWIP_NETIF_STATUS_CALLBACK
+void ppp_set_netif_statuscallback(int pd, netif_status_callback_fn status_callback);
+#endif /* LWIP_NETIF_STATUS_CALLBACK */
+#if LWIP_NETIF_LINK_CALLBACK
+void ppp_set_netif_linkcallback(int pd, netif_status_callback_fn link_callback);
+#endif /* LWIP_NETIF_LINK_CALLBACK */
+
+#endif /* PPP_SUPPORT */
+
+#endif /* PPP_H */
diff --git a/core/lwip/src/netif/ppp/ppp_oe.c b/core/lwip/src/netif/ppp/ppp_oe.c
new file mode 100644
index 00000000..040a0bc9
--- /dev/null
+++ b/core/lwip/src/netif/ppp/ppp_oe.c
@@ -0,0 +1,1132 @@
+/*****************************************************************************
+* ppp_oe.c - PPP Over Ethernet implementation for lwIP.
+*
+* Copyright (c) 2006 by Marc Boucher, Services Informatiques (MBSI) inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 06-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+*****************************************************************************/
+
+
+
+/* based on NetBSD: if_pppoe.c,v 1.64 2006/01/31 23:50:15 martin Exp */
+
+/*-
+ * Copyright (c) 2002 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Martin Husemann <martin@NetBSD.org>.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *        This product includes software developed by the NetBSD
+ *        Foundation, Inc. and its contributors.
+ * 4. Neither the name of The NetBSD Foundation nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "lwip/opt.h"
+
+#if PPPOE_SUPPORT /* don't build if not configured for use in lwipopts.h */
+
+#include "netif/ppp_oe.h"
+
+#include "ppp.h"
+#include "pppdebug.h"
+
+#include "lwip/timers.h"
+#include "lwip/memp.h"
+
+#include <string.h>
+#include <stdio.h>
+
+
+/* Add a 16 bit unsigned value to a buffer pointed to by PTR */
+#define PPPOE_ADD_16(PTR, VAL) \
+    *(PTR)++ = (u8_t)((VAL) / 256);    \
+    *(PTR)++ = (u8_t)((VAL) % 256)
+
+/* Add a complete PPPoE header to the buffer pointed to by PTR */
+#define PPPOE_ADD_HEADER(PTR, CODE, SESS, LEN)  \
+    *(PTR)++ = PPPOE_VERTYPE;  \
+    *(PTR)++ = (CODE);         \
+    PPPOE_ADD_16(PTR, SESS);   \
+    PPPOE_ADD_16(PTR, LEN)
+
+#define PPPOE_DISC_TIMEOUT (5*1000)  /* base for quick timeout calculation */
+#define PPPOE_SLOW_RETRY   (60*1000) /* persistent retry interval */
+#define PPPOE_DISC_MAXPADI  4        /* retry PADI four times (quickly) */
+#define PPPOE_DISC_MAXPADR  2        /* retry PADR twice */
+
+#ifdef PPPOE_SERVER
+#error "PPPOE_SERVER is not yet supported under lwIP!"
+/* from if_spppsubr.c */
+#define IFF_PASSIVE IFF_LINK0 /* wait passively for connection */
+#endif
+
+#ifndef PPPOE_ERRORSTRING_LEN
+#define PPPOE_ERRORSTRING_LEN     64
+#endif
+static char pppoe_error_tmp[PPPOE_ERRORSTRING_LEN];
+
+
+/* input routines */
+static void pppoe_dispatch_disc_pkt(struct netif *, struct pbuf *);
+
+/* management routines */
+static int pppoe_do_disconnect(struct pppoe_softc *);
+static void pppoe_abort_connect(struct pppoe_softc *);
+static void pppoe_clear_softc(struct pppoe_softc *, const char *);
+
+/* internal timeout handling */
+static void pppoe_timeout(void *);
+
+/* sending actual protocol controll packets */
+static err_t pppoe_send_padi(struct pppoe_softc *);
+static err_t pppoe_send_padr(struct pppoe_softc *);
+#ifdef PPPOE_SERVER
+static err_t pppoe_send_pado(struct pppoe_softc *);
+static err_t pppoe_send_pads(struct pppoe_softc *);
+#endif
+static err_t pppoe_send_padt(struct netif *, u_int, const u8_t *);
+
+/* internal helper functions */
+static struct pppoe_softc * pppoe_find_softc_by_session(u_int, struct netif *);
+static struct pppoe_softc * pppoe_find_softc_by_hunique(u8_t *, size_t, struct netif *);
+
+/** linked list of created pppoe interfaces */
+static struct pppoe_softc *pppoe_softc_list;
+
+err_t
+pppoe_create(struct netif *ethif, int pd, void (*linkStatusCB)(int pd, int up), struct pppoe_softc **scptr)
+{
+  struct pppoe_softc *sc;
+
+  sc = (struct pppoe_softc *)memp_malloc(MEMP_PPPOE_IF);
+  if (sc == NULL) {
+    *scptr = NULL;
+    return ERR_MEM;
+  }
+  memset(sc, 0, sizeof(struct pppoe_softc));
+
+  /* changed to real address later */
+  MEMCPY(&sc->sc_dest, ethbroadcast.addr, sizeof(sc->sc_dest));
+
+  sc->sc_pd = pd;
+  sc->sc_linkStatusCB = linkStatusCB;
+  sc->sc_ethif = ethif;
+
+  /* put the new interface at the head of the list */
+  sc->next = pppoe_softc_list;
+  pppoe_softc_list = sc;
+
+  *scptr = sc;
+
+  return ERR_OK;
+}
+
+err_t
+pppoe_destroy(struct netif *ifp)
+{
+  struct pppoe_softc *sc, *prev = NULL;
+
+  for (sc = pppoe_softc_list; sc != NULL; prev = sc, sc = sc->next) {
+    if (sc->sc_ethif == ifp) {
+      break;
+    }
+  }
+
+  if(!(sc && (sc->sc_ethif == ifp))) {
+    return ERR_IF;
+  }
+
+  sys_untimeout(pppoe_timeout, sc);
+  if (prev == NULL) {
+    /* remove sc from the head of the list */
+    pppoe_softc_list = sc->next;
+  } else {
+    /* remove sc from the list */
+    prev->next = sc->next;
+  }
+
+#ifdef PPPOE_TODO
+  if (sc->sc_concentrator_name) {
+    mem_free(sc->sc_concentrator_name);
+  }
+  if (sc->sc_service_name) {
+    mem_free(sc->sc_service_name);
+  }
+#endif /* PPPOE_TODO */
+  memp_free(MEMP_PPPOE_IF, sc);
+
+  return ERR_OK;
+}
+
+/*
+ * Find the interface handling the specified session.
+ * Note: O(number of sessions open), this is a client-side only, mean
+ * and lean implementation, so number of open sessions typically should
+ * be 1.
+ */
+static struct pppoe_softc *
+pppoe_find_softc_by_session(u_int session, struct netif *rcvif)
+{
+  struct pppoe_softc *sc;
+
+  if (session == 0) {
+    return NULL;
+  }
+
+  for (sc = pppoe_softc_list; sc != NULL; sc = sc->next) {
+    if (sc->sc_state == PPPOE_STATE_SESSION
+        && sc->sc_session == session) {
+      if (sc->sc_ethif == rcvif) {
+        return sc;
+      } else {
+        return NULL;
+      }
+    }
+  }
+  return NULL;
+}
+
+/* Check host unique token passed and return appropriate softc pointer,
+ * or NULL if token is bogus. */
+static struct pppoe_softc *
+pppoe_find_softc_by_hunique(u8_t *token, size_t len, struct netif *rcvif)
+{
+  struct pppoe_softc *sc, *t;
+
+  if (pppoe_softc_list == NULL) {
+    return NULL;
+  }
+
+  if (len != sizeof sc) {
+    return NULL;
+  }
+  MEMCPY(&t, token, len);
+
+  for (sc = pppoe_softc_list; sc != NULL; sc = sc->next) {
+    if (sc == t) {
+      break;
+    }
+  }
+
+  if (sc == NULL) {
+    PPPDEBUG(LOG_DEBUG, ("pppoe: alien host unique tag, no session found\n"));
+    return NULL;
+  }
+
+  /* should be safe to access *sc now */
+  if (sc->sc_state < PPPOE_STATE_PADI_SENT || sc->sc_state >= PPPOE_STATE_SESSION) {
+    printf("%c%c%"U16_F": host unique tag found, but it belongs to a connection in state %d\n",
+      sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num, sc->sc_state);
+    return NULL;
+  }
+  if (sc->sc_ethif != rcvif) {
+    printf("%c%c%"U16_F": wrong interface, not accepting host unique\n",
+      sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num);
+    return NULL;
+  }
+  return sc;
+}
+
+static void
+pppoe_linkstatus_up(struct pppoe_softc *sc)
+{
+  sc->sc_linkStatusCB(sc->sc_pd, 1);
+}
+
+/* analyze and handle a single received packet while not in session state */
+static void
+pppoe_dispatch_disc_pkt(struct netif *netif, struct pbuf *pb)
+{
+  u16_t tag, len;
+  u16_t session, plen;
+  struct pppoe_softc *sc;
+  const char *err_msg;
+  char devname[6];
+  u8_t *ac_cookie;
+  u16_t ac_cookie_len;
+#ifdef PPPOE_SERVER
+  u8_t *hunique;
+  size_t hunique_len;
+#endif
+  struct pppoehdr *ph;
+  struct pppoetag pt;
+  int off, err, errortag;
+  struct eth_hdr *ethhdr;
+
+  pb = pppSingleBuf(pb);
+
+  strcpy(devname, "pppoe");  /* as long as we don't know which instance */
+  err_msg = NULL;
+  errortag = 0;
+  if (pb->len < sizeof(*ethhdr)) {
+    goto done;
+  }
+  ethhdr = (struct eth_hdr *)pb->payload;
+  off = sizeof(*ethhdr);
+
+  ac_cookie = NULL;
+  ac_cookie_len = 0;
+#ifdef PPPOE_SERVER
+  hunique = NULL;
+  hunique_len = 0;
+#endif
+  session = 0;
+  if (pb->len - off < PPPOE_HEADERLEN) {
+    printf("pppoe: packet too short: %d\n", pb->len);
+    goto done;
+  }
+
+  ph = (struct pppoehdr *) (ethhdr + 1);
+  if (ph->vertype != PPPOE_VERTYPE) {
+    printf("pppoe: unknown version/type packet: 0x%x\n", ph->vertype);
+    goto done;
+  }
+  session = ntohs(ph->session);
+  plen = ntohs(ph->plen);
+  off += sizeof(*ph);
+
+  if (plen + off > pb->len) {
+    printf("pppoe: packet content does not fit: data available = %d, packet size = %u\n",
+        pb->len - off, plen);
+    goto done;
+  }
+  if(pb->tot_len == pb->len) {
+    pb->tot_len = pb->len = (u16_t)off + plen; /* ignore trailing garbage */
+  }
+  tag = 0;
+  len = 0;
+  sc = NULL;
+  while (off + sizeof(pt) <= pb->len) {
+    MEMCPY(&pt, (u8_t*)pb->payload + off, sizeof(pt));
+    tag = ntohs(pt.tag);
+    len = ntohs(pt.len);
+    if (off + sizeof(pt) + len > pb->len) {
+      printf("pppoe: tag 0x%x len 0x%x is too long\n", tag, len);
+      goto done;
+    }
+    switch (tag) {
+      case PPPOE_TAG_EOL:
+        goto breakbreak;
+      case PPPOE_TAG_SNAME:
+        break;  /* ignored */
+      case PPPOE_TAG_ACNAME:
+        break;  /* ignored */
+      case PPPOE_TAG_HUNIQUE:
+        if (sc != NULL) {
+          break;
+        }
+#ifdef PPPOE_SERVER
+        hunique = (u8_t*)pb->payload + off + sizeof(pt);
+        hunique_len = len;
+#endif
+        sc = pppoe_find_softc_by_hunique((u8_t*)pb->payload + off + sizeof(pt), len, netif);
+        if (sc != NULL) {
+          snprintf(devname, sizeof(devname), "%c%c%"U16_F, sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num);
+        }
+        break;
+      case PPPOE_TAG_ACCOOKIE:
+        if (ac_cookie == NULL) {
+          ac_cookie = (u8_t*)pb->payload + off + sizeof(pt);
+          ac_cookie_len = len;
+        }
+        break;
+      case PPPOE_TAG_SNAME_ERR:
+        err_msg = "SERVICE NAME ERROR";
+        errortag = 1;
+        break;
+      case PPPOE_TAG_ACSYS_ERR:
+        err_msg = "AC SYSTEM ERROR";
+        errortag = 1;
+        break;
+      case PPPOE_TAG_GENERIC_ERR:
+        err_msg = "GENERIC ERROR";
+        errortag = 1;
+        break;
+    }
+    if (err_msg) {
+      if (errortag && len) {
+        u16_t error_len = LWIP_MIN(len, sizeof(pppoe_error_tmp)-1);
+        strncpy(pppoe_error_tmp, (char*)pb->payload + off + sizeof(pt), error_len);
+        pppoe_error_tmp[error_len-1] = '\0';
+        printf("%s: %s: %s\n", devname, err_msg, pppoe_error_tmp);
+      } else {
+        printf("%s: %s\n", devname, err_msg);
+      }
+      if (errortag) {
+        goto done;
+      }
+    }
+    off += sizeof(pt) + len;
+  }
+
+breakbreak:;
+  switch (ph->code) {
+    case PPPOE_CODE_PADI:
+#ifdef PPPOE_SERVER
+      /*
+       * got service name, concentrator name, and/or host unique.
+       * ignore if we have no interfaces with IFF_PASSIVE|IFF_UP.
+       */
+      if (LIST_EMPTY(&pppoe_softc_list)) {
+        goto done;
+      }
+      LIST_FOREACH(sc, &pppoe_softc_list, sc_list) {
+        if (!(sc->sc_sppp.pp_if.if_flags & IFF_UP)) {
+          continue;
+        }
+        if (!(sc->sc_sppp.pp_if.if_flags & IFF_PASSIVE)) {
+          continue;
+        }
+        if (sc->sc_state == PPPOE_STATE_INITIAL) {
+          break;
+        }
+      }
+      if (sc == NULL) {
+        /* printf("pppoe: free passive interface is not found\n"); */
+        goto done;
+      }
+      if (hunique) {
+        if (sc->sc_hunique) {
+          mem_free(sc->sc_hunique);
+        }
+        sc->sc_hunique = mem_malloc(hunique_len);
+        if (sc->sc_hunique == NULL) {
+          goto done;
+        }
+        sc->sc_hunique_len = hunique_len;
+        MEMCPY(sc->sc_hunique, hunique, hunique_len);
+      }
+      MEMCPY(&sc->sc_dest, eh->ether_shost, sizeof sc->sc_dest);
+      sc->sc_state = PPPOE_STATE_PADO_SENT;
+      pppoe_send_pado(sc);
+      break;
+#endif /* PPPOE_SERVER */
+    case PPPOE_CODE_PADR:
+#ifdef PPPOE_SERVER
+      /*
+       * get sc from ac_cookie if IFF_PASSIVE
+       */
+      if (ac_cookie == NULL) {
+        /* be quiet if there is not a single pppoe instance */
+        printf("pppoe: received PADR but not includes ac_cookie\n");
+        goto done;
+      }
+      sc = pppoe_find_softc_by_hunique(ac_cookie, ac_cookie_len, netif);
+      if (sc == NULL) {
+        /* be quiet if there is not a single pppoe instance */
+        if (!LIST_EMPTY(&pppoe_softc_list)) {
+          printf("pppoe: received PADR but could not find request for it\n");
+        }
+        goto done;
+      }
+      if (sc->sc_state != PPPOE_STATE_PADO_SENT) {
+        printf("%c%c%"U16_F": received unexpected PADR\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num);
+        goto done;
+      }
+      if (hunique) {
+        if (sc->sc_hunique) {
+          mem_free(sc->sc_hunique);
+        }
+        sc->sc_hunique = mem_malloc(hunique_len);
+        if (sc->sc_hunique == NULL) {
+          goto done;
+        }
+        sc->sc_hunique_len = hunique_len;
+        MEMCPY(sc->sc_hunique, hunique, hunique_len);
+      }
+      pppoe_send_pads(sc);
+      sc->sc_state = PPPOE_STATE_SESSION;
+      pppoe_linkstatus_up(sc); /* notify upper layers */
+      break;
+#else
+      /* ignore, we are no access concentrator */
+      goto done;
+#endif /* PPPOE_SERVER */
+    case PPPOE_CODE_PADO:
+      if (sc == NULL) {
+        /* be quiet if there is not a single pppoe instance */
+        if (pppoe_softc_list != NULL) {
+          printf("pppoe: received PADO but could not find request for it\n");
+        }
+        goto done;
+      }
+      if (sc->sc_state != PPPOE_STATE_PADI_SENT) {
+        printf("%c%c%"U16_F": received unexpected PADO\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num);
+        goto done;
+      }
+      if (ac_cookie) {
+        sc->sc_ac_cookie_len = ac_cookie_len;
+        MEMCPY(sc->sc_ac_cookie, ac_cookie, ac_cookie_len);
+      }
+      MEMCPY(&sc->sc_dest, ethhdr->src.addr, sizeof(sc->sc_dest.addr));
+      sys_untimeout(pppoe_timeout, sc);
+      sc->sc_padr_retried = 0;
+      sc->sc_state = PPPOE_STATE_PADR_SENT;
+      if ((err = pppoe_send_padr(sc)) != 0) {
+        PPPDEBUG(LOG_DEBUG, ("pppoe: %c%c%"U16_F": failed to send PADR, error=%d\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num, err));
+      }
+      sys_timeout(PPPOE_DISC_TIMEOUT * (1 + sc->sc_padr_retried), pppoe_timeout, sc);
+      break;
+    case PPPOE_CODE_PADS:
+      if (sc == NULL) {
+        goto done;
+      }
+      sc->sc_session = session;
+      sys_untimeout(pppoe_timeout, sc);
+      PPPDEBUG(LOG_DEBUG, ("pppoe: %c%c%"U16_F": session 0x%x connected\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num, session));
+      sc->sc_state = PPPOE_STATE_SESSION;
+      pppoe_linkstatus_up(sc); /* notify upper layers */
+      break;
+    case PPPOE_CODE_PADT:
+      if (sc == NULL) {
+        goto done;
+      }
+      pppoe_clear_softc(sc, "received PADT");
+      break;
+    default:
+      if(sc) {
+        printf("%c%c%"U16_F": unknown code (0x%"X16_F") session = 0x%"X16_F"\n",
+            sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num,
+            (u16_t)ph->code, session);
+      } else {
+        printf("pppoe: unknown code (0x%"X16_F") session = 0x%"X16_F"\n", (u16_t)ph->code, session);
+      }
+      break;
+  }
+
+done:
+  pbuf_free(pb);
+  return;
+}
+
+void
+pppoe_disc_input(struct netif *netif, struct pbuf *p)
+{
+  /* avoid error messages if there is not a single pppoe instance */
+  if (pppoe_softc_list != NULL) {
+    pppoe_dispatch_disc_pkt(netif, p);
+  } else {
+    pbuf_free(p);
+  }
+}
+
+void
+pppoe_data_input(struct netif *netif, struct pbuf *pb)
+{
+  u16_t session, plen;
+  struct pppoe_softc *sc;
+  struct pppoehdr *ph;
+#ifdef PPPOE_TERM_UNKNOWN_SESSIONS
+  u8_t shost[ETHER_ADDR_LEN];
+#endif
+
+#ifdef PPPOE_TERM_UNKNOWN_SESSIONS
+  MEMCPY(shost, ((struct eth_hdr *)pb->payload)->src.addr, sizeof(shost));
+#endif
+  if (pbuf_header(pb, -(int)sizeof(struct eth_hdr)) != 0) {
+    /* bail out */
+    PPPDEBUG(LOG_ERR, ("pppoe_data_input: pbuf_header failed\n"));
+    LINK_STATS_INC(link.lenerr);
+    goto drop;
+  } 
+
+  pb = pppSingleBuf (pb);
+
+  if (pb->len <= PPPOE_HEADERLEN) {
+    printf("pppoe (data): dropping too short packet: %d bytes\n", pb->len);
+    goto drop;
+  }
+
+  if (pb->len < sizeof(*ph)) {
+    printf("pppoe_data_input: could not get PPPoE header\n");
+    goto drop;
+  }
+  ph = (struct pppoehdr *)pb->payload;
+
+  if (ph->vertype != PPPOE_VERTYPE) {
+    printf("pppoe (data): unknown version/type packet: 0x%x\n", ph->vertype);
+    goto drop;
+  }
+  if (ph->code != 0) {
+    goto drop;
+  }
+
+  session = ntohs(ph->session);
+  sc = pppoe_find_softc_by_session(session, netif);
+  if (sc == NULL) {
+#ifdef PPPOE_TERM_UNKNOWN_SESSIONS
+    printf("pppoe: input for unknown session 0x%x, sending PADT\n", session);
+    pppoe_send_padt(netif, session, shost);
+#endif
+    goto drop;
+  }
+
+  plen = ntohs(ph->plen);
+
+  if (pbuf_header(pb, -(int)(PPPOE_HEADERLEN)) != 0) {
+    /* bail out */
+    PPPDEBUG(LOG_ERR, ("pppoe_data_input: pbuf_header PPPOE_HEADERLEN failed\n"));
+    LINK_STATS_INC(link.lenerr);
+    goto drop;
+  } 
+
+  PPPDEBUG(LOG_DEBUG, ("pppoe_data_input: %c%c%"U16_F": pkthdr.len=%d, pppoe.len=%d\n",
+        sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num,
+        pb->len, plen));
+
+  if (pb->len < plen) {
+    goto drop;
+  }
+
+  pppInProcOverEthernet(sc->sc_pd, pb);
+
+  return;
+
+drop:
+  pbuf_free(pb);
+}
+
+static err_t
+pppoe_output(struct pppoe_softc *sc, struct pbuf *pb)
+{
+  struct eth_hdr *ethhdr;
+  u16_t etype;
+  err_t res;
+
+  if (!sc->sc_ethif) {
+    pbuf_free(pb);
+    return ERR_IF;
+  }
+
+  ethhdr = (struct eth_hdr *)pb->payload;
+  etype = sc->sc_state == PPPOE_STATE_SESSION ? ETHTYPE_PPPOE : ETHTYPE_PPPOEDISC;
+  ethhdr->type = htons(etype);
+  MEMCPY(ethhdr->dest.addr, sc->sc_dest.addr, sizeof(ethhdr->dest.addr));
+  MEMCPY(ethhdr->src.addr, ((struct eth_addr *)sc->sc_ethif->hwaddr)->addr, sizeof(ethhdr->src.addr));
+
+  PPPDEBUG(LOG_DEBUG, ("pppoe: %c%c%"U16_F" (%x) state=%d, session=0x%x output -> %02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F", len=%d\n",
+      sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num, etype,
+      sc->sc_state, sc->sc_session,
+      sc->sc_dest.addr[0], sc->sc_dest.addr[1], sc->sc_dest.addr[2], sc->sc_dest.addr[3], sc->sc_dest.addr[4], sc->sc_dest.addr[5],
+      pb->tot_len));
+
+  res = sc->sc_ethif->linkoutput(sc->sc_ethif, pb);
+
+  pbuf_free(pb);
+
+  return res;
+}
+
+static err_t
+pppoe_send_padi(struct pppoe_softc *sc)
+{
+  struct pbuf *pb;
+  u8_t *p;
+  int len;
+#ifdef PPPOE_TODO
+  int l1 = 0, l2 = 0; /* XXX: gcc */
+#endif /* PPPOE_TODO */
+
+  if (sc->sc_state >PPPOE_STATE_PADI_SENT) {
+    PPPDEBUG(LOG_ERR, ("ERROR: pppoe_send_padi in state %d", sc->sc_state));
+  }
+
+  /* calculate length of frame (excluding ethernet header + pppoe header) */
+  len = 2 + 2 + 2 + 2 + sizeof sc;  /* service name tag is required, host unique is send too */
+#ifdef PPPOE_TODO
+  if (sc->sc_service_name != NULL) {
+    l1 = (int)strlen(sc->sc_service_name);
+    len += l1;
+  }
+  if (sc->sc_concentrator_name != NULL) {
+    l2 = (int)strlen(sc->sc_concentrator_name);
+    len += 2 + 2 + l2;
+  }
+#endif /* PPPOE_TODO */
+  LWIP_ASSERT("sizeof(struct eth_hdr) + PPPOE_HEADERLEN + len <= 0xffff",
+    sizeof(struct eth_hdr) + PPPOE_HEADERLEN + len <= 0xffff);
+
+  /* allocate a buffer */
+  pb = pbuf_alloc(PBUF_LINK, (u16_t)(sizeof(struct eth_hdr) + PPPOE_HEADERLEN + len), PBUF_RAM);
+  if (!pb) {
+    return ERR_MEM;
+  }
+  LWIP_ASSERT("pb->tot_len == pb->len", pb->tot_len == pb->len);
+
+  p = (u8_t*)pb->payload + sizeof (struct eth_hdr);
+  /* fill in pkt */
+  PPPOE_ADD_HEADER(p, PPPOE_CODE_PADI, 0, (u16_t)len);
+  PPPOE_ADD_16(p, PPPOE_TAG_SNAME);
+#ifdef PPPOE_TODO
+  if (sc->sc_service_name != NULL) {
+    PPPOE_ADD_16(p, l1);
+    MEMCPY(p, sc->sc_service_name, l1);
+    p += l1;
+  } else
+#endif /* PPPOE_TODO */
+  {
+    PPPOE_ADD_16(p, 0);
+  }
+#ifdef PPPOE_TODO
+  if (sc->sc_concentrator_name != NULL) {
+    PPPOE_ADD_16(p, PPPOE_TAG_ACNAME);
+    PPPOE_ADD_16(p, l2);
+    MEMCPY(p, sc->sc_concentrator_name, l2);
+    p += l2;
+  }
+#endif /* PPPOE_TODO */
+  PPPOE_ADD_16(p, PPPOE_TAG_HUNIQUE);
+  PPPOE_ADD_16(p, sizeof(sc));
+  MEMCPY(p, &sc, sizeof sc);
+
+  /* send pkt */
+  return pppoe_output(sc, pb);
+}
+
+static void
+pppoe_timeout(void *arg)
+{
+  int retry_wait, err;
+  struct pppoe_softc *sc = (struct pppoe_softc*)arg;
+
+  PPPDEBUG(LOG_DEBUG, ("pppoe: %c%c%"U16_F": timeout\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num));
+
+  switch (sc->sc_state) {
+    case PPPOE_STATE_PADI_SENT:
+      /*
+       * We have two basic ways of retrying:
+       *  - Quick retry mode: try a few times in short sequence
+       *  - Slow retry mode: we already had a connection successfully
+       *    established and will try infinitely (without user
+       *    intervention)
+       * We only enter slow retry mode if IFF_LINK1 (aka autodial)
+       * is not set.
+       */
+
+      /* initialize for quick retry mode */
+      retry_wait = PPPOE_DISC_TIMEOUT * (1 + sc->sc_padi_retried);
+
+      sc->sc_padi_retried++;
+      if (sc->sc_padi_retried >= PPPOE_DISC_MAXPADI) {
+#if 0
+        if ((sc->sc_sppp.pp_if.if_flags & IFF_LINK1) == 0) {
+          /* slow retry mode */
+          retry_wait = PPPOE_SLOW_RETRY;
+        } else
+#endif
+        {
+          pppoe_abort_connect(sc);
+          return;
+        }
+      }
+      if ((err = pppoe_send_padi(sc)) != 0) {
+        sc->sc_padi_retried--;
+        PPPDEBUG(LOG_DEBUG, ("pppoe: %c%c%"U16_F": failed to transmit PADI, error=%d\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num, err));
+      }
+      sys_timeout(retry_wait, pppoe_timeout, sc);
+      break;
+
+    case PPPOE_STATE_PADR_SENT:
+      sc->sc_padr_retried++;
+      if (sc->sc_padr_retried >= PPPOE_DISC_MAXPADR) {
+        MEMCPY(&sc->sc_dest, ethbroadcast.addr, sizeof(sc->sc_dest));
+        sc->sc_state = PPPOE_STATE_PADI_SENT;
+        sc->sc_padr_retried = 0;
+        if ((err = pppoe_send_padi(sc)) != 0) {
+          PPPDEBUG(LOG_DEBUG, ("pppoe: %c%c%"U16_F": failed to send PADI, error=%d\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num, err));
+        }
+        sys_timeout(PPPOE_DISC_TIMEOUT * (1 + sc->sc_padi_retried), pppoe_timeout, sc);
+        return;
+      }
+      if ((err = pppoe_send_padr(sc)) != 0) {
+        sc->sc_padr_retried--;
+        PPPDEBUG(LOG_DEBUG, ("pppoe: %c%c%"U16_F": failed to send PADR, error=%d\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num, err));
+      }
+      sys_timeout(PPPOE_DISC_TIMEOUT * (1 + sc->sc_padr_retried), pppoe_timeout, sc);
+      break;
+    case PPPOE_STATE_CLOSING:
+      pppoe_do_disconnect(sc);
+      break;
+    default:
+      return;  /* all done, work in peace */
+  }
+}
+
+/* Start a connection (i.e. initiate discovery phase) */
+int
+pppoe_connect(struct pppoe_softc *sc)
+{
+  int err;
+
+  if (sc->sc_state != PPPOE_STATE_INITIAL) {
+    return EBUSY;
+  }
+
+#ifdef PPPOE_SERVER
+  /* wait PADI if IFF_PASSIVE */
+  if ((sc->sc_sppp.pp_if.if_flags & IFF_PASSIVE)) {
+    return 0;
+  }
+#endif
+  /* save state, in case we fail to send PADI */
+  sc->sc_state = PPPOE_STATE_PADI_SENT;
+  sc->sc_padr_retried = 0;
+  err = pppoe_send_padi(sc);
+  PPPDEBUG(LOG_DEBUG, ("pppoe: %c%c%"U16_F": failed to send PADI, error=%d\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num, err));
+  sys_timeout(PPPOE_DISC_TIMEOUT, pppoe_timeout, sc);
+  return err;
+}
+
+/* disconnect */
+void
+pppoe_disconnect(struct pppoe_softc *sc)
+{
+  if (sc->sc_state < PPPOE_STATE_SESSION) {
+    return;
+  }
+  /*
+   * Do not call pppoe_disconnect here, the upper layer state
+   * machine gets confused by this. We must return from this
+   * function and defer disconnecting to the timeout handler.
+   */
+  sc->sc_state = PPPOE_STATE_CLOSING;
+  sys_timeout(20, pppoe_timeout, sc);
+}
+
+static int
+pppoe_do_disconnect(struct pppoe_softc *sc)
+{
+  int err;
+
+  if (sc->sc_state < PPPOE_STATE_SESSION) {
+    err = EBUSY;
+  } else {
+    PPPDEBUG(LOG_DEBUG, ("pppoe: %c%c%"U16_F": disconnecting\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num));
+    err = pppoe_send_padt(sc->sc_ethif, sc->sc_session, (const u8_t *)&sc->sc_dest);
+  }
+
+  /* cleanup softc */
+  sc->sc_state = PPPOE_STATE_INITIAL;
+  MEMCPY(&sc->sc_dest, ethbroadcast.addr, sizeof(sc->sc_dest));
+  sc->sc_ac_cookie_len = 0;
+#ifdef PPPOE_SERVER
+  if (sc->sc_hunique) {
+    mem_free(sc->sc_hunique);
+    sc->sc_hunique = NULL;
+  }
+  sc->sc_hunique_len = 0;
+#endif
+  sc->sc_session = 0;
+
+  sc->sc_linkStatusCB(sc->sc_pd, 0); /* notify upper layers */
+
+  return err;
+}
+
+/* Connection attempt aborted */
+static void
+pppoe_abort_connect(struct pppoe_softc *sc)
+{
+  printf("%c%c%"U16_F": could not establish connection\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num);
+  sc->sc_state = PPPOE_STATE_CLOSING;
+
+  sc->sc_linkStatusCB(sc->sc_pd, 0); /* notify upper layers */
+
+  /* clear connection state */
+  MEMCPY(&sc->sc_dest, ethbroadcast.addr, sizeof(sc->sc_dest));
+  sc->sc_state = PPPOE_STATE_INITIAL;
+}
+
+/* Send a PADR packet */
+static err_t
+pppoe_send_padr(struct pppoe_softc *sc)
+{
+  struct pbuf *pb;
+  u8_t *p;
+  size_t len;
+#ifdef PPPOE_TODO
+  size_t l1 = 0; /* XXX: gcc */
+#endif /* PPPOE_TODO */
+
+  if (sc->sc_state != PPPOE_STATE_PADR_SENT) {
+    return ERR_CONN;
+  }
+
+  len = 2 + 2 + 2 + 2 + sizeof(sc);    /* service name, host unique */
+#ifdef PPPOE_TODO
+  if (sc->sc_service_name != NULL) {    /* service name tag maybe empty */
+    l1 = strlen(sc->sc_service_name);
+    len += l1;
+  }
+#endif /* PPPOE_TODO */
+  if (sc->sc_ac_cookie_len > 0) {
+    len += 2 + 2 + sc->sc_ac_cookie_len;  /* AC cookie */
+  }
+  LWIP_ASSERT("sizeof(struct eth_hdr) + PPPOE_HEADERLEN + len <= 0xffff",
+    sizeof(struct eth_hdr) + PPPOE_HEADERLEN + len <= 0xffff);
+  pb = pbuf_alloc(PBUF_LINK, (u16_t)(sizeof(struct eth_hdr) + PPPOE_HEADERLEN + len), PBUF_RAM);
+  if (!pb) {
+    return ERR_MEM;
+  }
+  LWIP_ASSERT("pb->tot_len == pb->len", pb->tot_len == pb->len);
+  p = (u8_t*)pb->payload + sizeof (struct eth_hdr);
+  PPPOE_ADD_HEADER(p, PPPOE_CODE_PADR, 0, len);
+  PPPOE_ADD_16(p, PPPOE_TAG_SNAME);
+#ifdef PPPOE_TODO
+  if (sc->sc_service_name != NULL) {
+    PPPOE_ADD_16(p, l1);
+    MEMCPY(p, sc->sc_service_name, l1);
+    p += l1;
+  } else
+#endif /* PPPOE_TODO */
+  {
+    PPPOE_ADD_16(p, 0);
+  }
+  if (sc->sc_ac_cookie_len > 0) {
+    PPPOE_ADD_16(p, PPPOE_TAG_ACCOOKIE);
+    PPPOE_ADD_16(p, sc->sc_ac_cookie_len);
+    MEMCPY(p, sc->sc_ac_cookie, sc->sc_ac_cookie_len);
+    p += sc->sc_ac_cookie_len;
+  }
+  PPPOE_ADD_16(p, PPPOE_TAG_HUNIQUE);
+  PPPOE_ADD_16(p, sizeof(sc));
+  MEMCPY(p, &sc, sizeof sc);
+
+  return pppoe_output(sc, pb);
+}
+
+/* send a PADT packet */
+static err_t
+pppoe_send_padt(struct netif *outgoing_if, u_int session, const u8_t *dest)
+{
+  struct pbuf *pb;
+  struct eth_hdr *ethhdr;
+  err_t res;
+  u8_t *p;
+
+  pb = pbuf_alloc(PBUF_LINK, sizeof(struct eth_hdr) + PPPOE_HEADERLEN, PBUF_RAM);
+  if (!pb) {
+    return ERR_MEM;
+  }
+  LWIP_ASSERT("pb->tot_len == pb->len", pb->tot_len == pb->len);
+
+  ethhdr = (struct eth_hdr *)pb->payload;
+  ethhdr->type = PP_HTONS(ETHTYPE_PPPOEDISC);
+  MEMCPY(ethhdr->dest.addr, dest, sizeof(ethhdr->dest.addr));
+  MEMCPY(ethhdr->src.addr, ((struct eth_addr *)outgoing_if->hwaddr)->addr, sizeof(ethhdr->src.addr));
+
+  p = (u8_t*)(ethhdr + 1);
+  PPPOE_ADD_HEADER(p, PPPOE_CODE_PADT, session, 0);
+
+  res = outgoing_if->linkoutput(outgoing_if, pb);
+
+  pbuf_free(pb);
+
+  return res;
+}
+
+#ifdef PPPOE_SERVER
+static err_t
+pppoe_send_pado(struct pppoe_softc *sc)
+{
+  struct pbuf *pb;
+  u8_t *p;
+  size_t len;
+
+  if (sc->sc_state != PPPOE_STATE_PADO_SENT) {
+    return ERR_CONN;
+  }
+
+  /* calc length */
+  len = 0;
+  /* include ac_cookie */
+  len += 2 + 2 + sizeof(sc);
+  /* include hunique */
+  len += 2 + 2 + sc->sc_hunique_len;
+  pb = pbuf_alloc(PBUF_LINK, sizeof(struct eth_hdr) + PPPOE_HEADERLEN + len, PBUF_RAM);
+  if (!pb) {
+    return ERR_MEM;
+  }
+  LWIP_ASSERT("pb->tot_len == pb->len", pb->tot_len == pb->len);
+  p = (u8_t*)pb->payload + sizeof (struct eth_hdr);
+  PPPOE_ADD_HEADER(p, PPPOE_CODE_PADO, 0, len);
+  PPPOE_ADD_16(p, PPPOE_TAG_ACCOOKIE);
+  PPPOE_ADD_16(p, sizeof(sc));
+  MEMCPY(p, &sc, sizeof(sc));
+  p += sizeof(sc);
+  PPPOE_ADD_16(p, PPPOE_TAG_HUNIQUE);
+  PPPOE_ADD_16(p, sc->sc_hunique_len);
+  MEMCPY(p, sc->sc_hunique, sc->sc_hunique_len);
+  return pppoe_output(sc, pb);
+}
+
+static err_t
+pppoe_send_pads(struct pppoe_softc *sc)
+{
+  struct pbuf *pb;
+  u8_t *p;
+  size_t len, l1 = 0;  /* XXX: gcc */
+
+  if (sc->sc_state != PPPOE_STATE_PADO_SENT) {
+    return ERR_CONN;
+  }
+
+  sc->sc_session = mono_time.tv_sec % 0xff + 1;
+  /* calc length */
+  len = 0;
+  /* include hunique */
+  len += 2 + 2 + 2 + 2 + sc->sc_hunique_len;  /* service name, host unique*/
+  if (sc->sc_service_name != NULL) {    /* service name tag maybe empty */
+    l1 = strlen(sc->sc_service_name);
+    len += l1;
+  }
+  pb = pbuf_alloc(PBUF_LINK, sizeof(struct eth_hdr) + PPPOE_HEADERLEN + len, PBUF_RAM);
+  if (!pb) {
+    return ERR_MEM;
+  }
+  LWIP_ASSERT("pb->tot_len == pb->len", pb->tot_len == pb->len);
+  p = (u8_t*)pb->payload + sizeof (struct eth_hdr);
+  PPPOE_ADD_HEADER(p, PPPOE_CODE_PADS, sc->sc_session, len);
+  PPPOE_ADD_16(p, PPPOE_TAG_SNAME);
+  if (sc->sc_service_name != NULL) {
+    PPPOE_ADD_16(p, l1);
+    MEMCPY(p, sc->sc_service_name, l1);
+    p += l1;
+  } else {
+    PPPOE_ADD_16(p, 0);
+  }
+  PPPOE_ADD_16(p, PPPOE_TAG_HUNIQUE);
+  PPPOE_ADD_16(p, sc->sc_hunique_len);
+  MEMCPY(p, sc->sc_hunique, sc->sc_hunique_len);
+  return pppoe_output(sc, pb);
+}
+#endif
+
+err_t
+pppoe_xmit(struct pppoe_softc *sc, struct pbuf *pb)
+{
+  u8_t *p;
+  size_t len;
+
+  /* are we ready to process data yet? */
+  if (sc->sc_state < PPPOE_STATE_SESSION) {
+    /*sppp_flush(&sc->sc_sppp.pp_if);*/
+    pbuf_free(pb);
+    return ERR_CONN;
+  }
+
+  len = pb->tot_len;
+
+  /* make room for Ethernet header - should not fail */
+  if (pbuf_header(pb, sizeof(struct eth_hdr) + PPPOE_HEADERLEN) != 0) {
+    /* bail out */
+    PPPDEBUG(LOG_ERR, ("pppoe: %c%c%"U16_F": pppoe_xmit: could not allocate room for header\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num));
+    LINK_STATS_INC(link.lenerr);
+    pbuf_free(pb);
+    return ERR_BUF;
+  } 
+
+  p = (u8_t*)pb->payload + sizeof(struct eth_hdr);
+  PPPOE_ADD_HEADER(p, 0, sc->sc_session, len);
+
+  return pppoe_output(sc, pb);
+}
+
+#if 0 /*def PFIL_HOOKS*/
+static int
+pppoe_ifattach_hook(void *arg, struct pbuf **mp, struct netif *ifp, int dir)
+{
+  struct pppoe_softc *sc;
+  int s;
+
+  if (mp != (struct pbuf **)PFIL_IFNET_DETACH) {
+    return 0;
+  }
+
+  LIST_FOREACH(sc, &pppoe_softc_list, sc_list) {
+    if (sc->sc_ethif != ifp) {
+      continue;
+    }
+    if (sc->sc_sppp.pp_if.if_flags & IFF_UP) {
+      sc->sc_sppp.pp_if.if_flags &= ~(IFF_UP|IFF_RUNNING);
+      printf("%c%c%"U16_F": ethernet interface detached, going down\n",
+          sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num);
+    }
+    sc->sc_ethif = NULL;
+    pppoe_clear_softc(sc, "ethernet interface detached");
+  }
+
+  return 0;
+}
+#endif
+
+static void
+pppoe_clear_softc(struct pppoe_softc *sc, const char *message)
+{
+  LWIP_UNUSED_ARG(message);
+
+  /* stop timer */
+  sys_untimeout(pppoe_timeout, sc);
+  PPPDEBUG(LOG_DEBUG, ("pppoe: %c%c%"U16_F": session 0x%x terminated, %s\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num, sc->sc_session, message));
+
+  /* fix our state */
+  sc->sc_state = PPPOE_STATE_INITIAL;
+
+  /* notify upper layers */
+  sc->sc_linkStatusCB(sc->sc_pd, 0);
+
+  /* clean up softc */
+  MEMCPY(&sc->sc_dest, ethbroadcast.addr, sizeof(sc->sc_dest));
+  sc->sc_ac_cookie_len = 0;
+  sc->sc_session = 0;
+}
+
+#endif /* PPPOE_SUPPORT */
+
diff --git a/core/lwip/src/netif/ppp/pppdebug.h b/core/lwip/src/netif/ppp/pppdebug.h
new file mode 100644
index 00000000..81349971
--- /dev/null
+++ b/core/lwip/src/netif/ppp/pppdebug.h
@@ -0,0 +1,73 @@
+/*****************************************************************************
+* pppdebug.h - System debugging utilities.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* portions Copyright (c) 1998 Global Election Systems Inc.
+* portions Copyright (c) 2001 by Cognizant Pty Ltd.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY (please don't use tabs!)
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 98-07-29 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
+*   Original.
+*
+*****************************************************************************
+*/
+#ifndef PPPDEBUG_H
+#define PPPDEBUG_H
+
+/* Trace levels. */
+#define LOG_CRITICAL  (PPP_DEBUG | LWIP_DBG_LEVEL_SEVERE)
+#define LOG_ERR       (PPP_DEBUG | LWIP_DBG_LEVEL_SEVERE)
+#define LOG_NOTICE    (PPP_DEBUG | LWIP_DBG_LEVEL_WARNING)
+#define LOG_WARNING   (PPP_DEBUG | LWIP_DBG_LEVEL_WARNING)
+#define LOG_INFO      (PPP_DEBUG)
+#define LOG_DETAIL    (PPP_DEBUG)
+#define LOG_DEBUG     (PPP_DEBUG)
+
+
+#define TRACELCP PPP_DEBUG
+
+#if PPP_DEBUG
+
+#define AUTHDEBUG(a, b) LWIP_DEBUGF(a, b)
+#define IPCPDEBUG(a, b) LWIP_DEBUGF(a, b)
+#define UPAPDEBUG(a, b) LWIP_DEBUGF(a, b)
+#define LCPDEBUG(a, b)  LWIP_DEBUGF(a, b)
+#define FSMDEBUG(a, b)  LWIP_DEBUGF(a, b)
+#define CHAPDEBUG(a, b) LWIP_DEBUGF(a, b)
+#define PPPDEBUG(a, b)  LWIP_DEBUGF(a, b)
+
+#else /* PPP_DEBUG */
+
+#define AUTHDEBUG(a, b)
+#define IPCPDEBUG(a, b)
+#define UPAPDEBUG(a, b)
+#define LCPDEBUG(a, b)
+#define FSMDEBUG(a, b)
+#define CHAPDEBUG(a, b)
+#define PPPDEBUG(a, b)
+
+#endif /* PPP_DEBUG */
+
+#endif /* PPPDEBUG_H */
diff --git a/core/lwip/src/netif/ppp/randm.c b/core/lwip/src/netif/ppp/randm.c
new file mode 100644
index 00000000..2f35caf6
--- /dev/null
+++ b/core/lwip/src/netif/ppp/randm.c
@@ -0,0 +1,249 @@
+/*****************************************************************************
+* randm.c - Random number generator program file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* Copyright (c) 1998 by Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 98-06-03 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
+*   Extracted from avos.
+*****************************************************************************/
+
+#include "lwip/opt.h"
+
+#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
+
+#include "md5.h"
+#include "randm.h"
+
+#include "ppp.h"
+#include "pppdebug.h"
+
+#include <string.h>
+
+#if MD5_SUPPORT /* this module depends on MD5 */
+#define RANDPOOLSZ 16   /* Bytes stored in the pool of randomness. */
+
+/*****************************/
+/*** LOCAL DATA STRUCTURES ***/
+/*****************************/
+static char randPool[RANDPOOLSZ];   /* Pool of randomness. */
+static long randCount = 0;      /* Pseudo-random incrementer */
+
+
+/***********************************/
+/*** PUBLIC FUNCTION DEFINITIONS ***/
+/***********************************/
+/*
+ * Initialize the random number generator.
+ *
+ * Since this is to be called on power up, we don't have much
+ *  system randomess to work with.  Here all we use is the
+ *  real-time clock.  We'll accumulate more randomness as soon
+ *  as things start happening.
+ */
+void
+avRandomInit()
+{
+  avChurnRand(NULL, 0);
+}
+
+/*
+ * Churn the randomness pool on a random event.  Call this early and often
+ *  on random and semi-random system events to build randomness in time for
+ *  usage.  For randomly timed events, pass a null pointer and a zero length
+ *  and this will use the system timer and other sources to add randomness.
+ *  If new random data is available, pass a pointer to that and it will be
+ *  included.
+ *
+ * Ref: Applied Cryptography 2nd Ed. by Bruce Schneier p. 427
+ */
+void
+avChurnRand(char *randData, u32_t randLen)
+{
+  MD5_CTX md5;
+
+  /* LWIP_DEBUGF(LOG_INFO, ("churnRand: %u@%P\n", randLen, randData)); */
+  MD5Init(&md5);
+  MD5Update(&md5, (u_char *)randPool, sizeof(randPool));
+  if (randData) {
+    MD5Update(&md5, (u_char *)randData, randLen);
+  } else {
+    struct {
+      /* INCLUDE fields for any system sources of randomness */
+      char foobar;
+    } sysData;
+
+    /* Load sysData fields here. */
+    MD5Update(&md5, (u_char *)&sysData, sizeof(sysData));
+  }
+  MD5Final((u_char *)randPool, &md5);
+/*  LWIP_DEBUGF(LOG_INFO, ("churnRand: -> 0\n")); */
+}
+
+/*
+ * Use the random pool to generate random data.  This degrades to pseudo
+ *  random when used faster than randomness is supplied using churnRand().
+ * Note: It's important that there be sufficient randomness in randPool
+ *  before this is called for otherwise the range of the result may be
+ *  narrow enough to make a search feasible.
+ *
+ * Ref: Applied Cryptography 2nd Ed. by Bruce Schneier p. 427
+ *
+ * XXX Why does he not just call churnRand() for each block?  Probably
+ *  so that you don't ever publish the seed which could possibly help
+ *  predict future values.
+ * XXX Why don't we preserve md5 between blocks and just update it with
+ *  randCount each time?  Probably there is a weakness but I wish that
+ *  it was documented.
+ */
+void
+avGenRand(char *buf, u32_t bufLen)
+{
+  MD5_CTX md5;
+  u_char tmp[16];
+  u32_t n;
+
+  while (bufLen > 0) {
+    n = LWIP_MIN(bufLen, RANDPOOLSZ);
+    MD5Init(&md5);
+    MD5Update(&md5, (u_char *)randPool, sizeof(randPool));
+    MD5Update(&md5, (u_char *)&randCount, sizeof(randCount));
+    MD5Final(tmp, &md5);
+    randCount++;
+    MEMCPY(buf, tmp, n);
+    buf += n;
+    bufLen -= n;
+  }
+}
+
+/*
+ * Return a new random number.
+ */
+u32_t
+avRandom()
+{
+  u32_t newRand;
+
+  avGenRand((char *)&newRand, sizeof(newRand));
+
+  return newRand;
+}
+
+#else /* MD5_SUPPORT */
+
+/*****************************/
+/*** LOCAL DATA STRUCTURES ***/
+/*****************************/
+static int  avRandomized = 0;       /* Set when truely randomized. */
+static u32_t avRandomSeed = 0;      /* Seed used for random number generation. */
+
+
+/***********************************/
+/*** PUBLIC FUNCTION DEFINITIONS ***/
+/***********************************/
+/*
+ * Initialize the random number generator.
+ *
+ * Here we attempt to compute a random number seed but even if
+ * it isn't random, we'll randomize it later.
+ *
+ * The current method uses the fields from the real time clock,
+ * the idle process counter, the millisecond counter, and the
+ * hardware timer tick counter.  When this is invoked
+ * in startup(), then the idle counter and timer values may
+ * repeat after each boot and the real time clock may not be
+ * operational.  Thus we call it again on the first random
+ * event.
+ */
+void
+avRandomInit()
+{
+#if 0
+  /* Get a pointer into the last 4 bytes of clockBuf. */
+  u32_t *lptr1 = (u32_t *)((char *)&clockBuf[3]);
+
+  /*
+   * Initialize our seed using the real-time clock, the idle
+   * counter, the millisecond timer, and the hardware timer
+   * tick counter.  The real-time clock and the hardware
+   * tick counter are the best sources of randomness but
+   * since the tick counter is only 16 bit (and truncated
+   * at that), the idle counter and millisecond timer
+   * (which may be small values) are added to help
+   * randomize the lower 16 bits of the seed.
+   */
+  readClk();
+  avRandomSeed += *(u32_t *)clockBuf + *lptr1 + OSIdleCtr
+           + ppp_mtime() + ((u32_t)TM1 << 16) + TM1;
+#else
+  avRandomSeed += sys_jiffies(); /* XXX */
+#endif
+
+  /* Initialize the Borland random number generator. */
+  srand((unsigned)avRandomSeed);
+}
+
+/*
+ * Randomize our random seed value.  Here we use the fact that
+ * this function is called at *truely random* times by the polling
+ * and network functions.  Here we only get 16 bits of new random
+ * value but we use the previous value to randomize the other 16
+ * bits.
+ */
+void
+avRandomize(void)
+{
+  static u32_t last_jiffies;
+
+  if (!avRandomized) {
+    avRandomized = !0;
+    avRandomInit();
+    /* The initialization function also updates the seed. */
+  } else {
+    /* avRandomSeed += (avRandomSeed << 16) + TM1; */
+    avRandomSeed += (sys_jiffies() - last_jiffies); /* XXX */
+  }
+  last_jiffies = sys_jiffies();
+}
+
+/*
+ * Return a new random number.
+ * Here we use the Borland rand() function to supply a pseudo random
+ * number which we make truely random by combining it with our own
+ * seed which is randomized by truely random events. 
+ * Thus the numbers will be truely random unless there have been no
+ * operator or network events in which case it will be pseudo random
+ * seeded by the real time clock.
+ */
+u32_t
+avRandom()
+{
+  return ((((u32_t)rand() << 16) + rand()) + avRandomSeed);
+}
+
+#endif /* MD5_SUPPORT */
+
+#endif /* PPP_SUPPORT */
diff --git a/core/lwip/src/netif/ppp/randm.h b/core/lwip/src/netif/ppp/randm.h
new file mode 100644
index 00000000..a0984b02
--- /dev/null
+++ b/core/lwip/src/netif/ppp/randm.h
@@ -0,0 +1,81 @@
+/*****************************************************************************
+* randm.h - Random number generator header file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* Copyright (c) 1998 Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 98-05-29 Guy Lancaster <glanca@gesn.com>, Global Election Systems Inc.
+*   Extracted from avos.
+*****************************************************************************/
+
+#ifndef RANDM_H
+#define RANDM_H
+
+/***********************
+*** PUBLIC FUNCTIONS ***
+***********************/
+/*
+ * Initialize the random number generator.
+ */
+void avRandomInit(void);
+
+/*
+ * Churn the randomness pool on a random event.  Call this early and often
+ * on random and semi-random system events to build randomness in time for
+ * usage.  For randomly timed events, pass a null pointer and a zero length
+ * and this will use the system timer and other sources to add randomness.
+ * If new random data is available, pass a pointer to that and it will be
+ * included.
+ */
+void avChurnRand(char *randData, u32_t randLen);
+
+/*
+ * Randomize our random seed value.  To be called for truely random events
+ * such as user operations and network traffic.
+ */
+#if MD5_SUPPORT
+#define avRandomize() avChurnRand(NULL, 0)
+#else  /* MD5_SUPPORT */
+void avRandomize(void);
+#endif /* MD5_SUPPORT */
+
+/*
+ * Use the random pool to generate random data.  This degrades to pseudo
+ * random when used faster than randomness is supplied using churnRand().
+ * Thus it's important to make sure that the results of this are not
+ * published directly because one could predict the next result to at
+ * least some degree.  Also, it's important to get a good seed before
+ * the first use.
+ */
+void avGenRand(char *buf, u32_t bufLen);
+
+/*
+ * Return a new random number.
+ */
+u32_t avRandom(void);
+
+
+#endif /* RANDM_H */
diff --git a/core/lwip/src/netif/ppp/vj.c b/core/lwip/src/netif/ppp/vj.c
new file mode 100644
index 00000000..b7f2d54c
--- /dev/null
+++ b/core/lwip/src/netif/ppp/vj.c
@@ -0,0 +1,652 @@
+/*
+ * Routines to compress and uncompess tcp packets (for transmission
+ * over low speed serial lines.
+ *
+ * Copyright (c) 1989 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by the University of California, Berkeley.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989:
+ *   Initial distribution.
+ *
+ * Modified June 1993 by Paul Mackerras, paulus@cs.anu.edu.au,
+ * so that the entire packet being decompressed doesn't have
+ * to be in contiguous memory (just the compressed header).
+ *
+ * Modified March 1998 by Guy Lancaster, glanca@gesn.com,
+ * for a 16 bit processor.
+ */
+
+#include "lwip/opt.h"
+
+#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
+
+#include "ppp.h"
+#include "pppdebug.h"
+
+#include "vj.h"
+
+#include <string.h>
+
+#if VJ_SUPPORT
+
+#if LINK_STATS
+#define INCR(counter) ++comp->stats.counter
+#else
+#define INCR(counter)
+#endif
+
+void
+vj_compress_init(struct vjcompress *comp)
+{
+  register u_char i;
+  register struct cstate *tstate = comp->tstate;
+  
+#if MAX_SLOTS == 0
+  memset((char *)comp, 0, sizeof(*comp));
+#endif
+  comp->maxSlotIndex = MAX_SLOTS - 1;
+  comp->compressSlot = 0;    /* Disable slot ID compression by default. */
+  for (i = MAX_SLOTS - 1; i > 0; --i) {
+    tstate[i].cs_id = i;
+    tstate[i].cs_next = &tstate[i - 1];
+  }
+  tstate[0].cs_next = &tstate[MAX_SLOTS - 1];
+  tstate[0].cs_id = 0;
+  comp->last_cs = &tstate[0];
+  comp->last_recv = 255;
+  comp->last_xmit = 255;
+  comp->flags = VJF_TOSS;
+}
+
+
+/* ENCODE encodes a number that is known to be non-zero.  ENCODEZ
+ * checks for zero (since zero has to be encoded in the long, 3 byte
+ * form).
+ */
+#define ENCODE(n) { \
+  if ((u_short)(n) >= 256) { \
+    *cp++ = 0; \
+    cp[1] = (u_char)(n); \
+    cp[0] = (u_char)((n) >> 8); \
+    cp += 2; \
+  } else { \
+    *cp++ = (u_char)(n); \
+  } \
+}
+#define ENCODEZ(n) { \
+  if ((u_short)(n) >= 256 || (u_short)(n) == 0) { \
+    *cp++ = 0; \
+    cp[1] = (u_char)(n); \
+    cp[0] = (u_char)((n) >> 8); \
+    cp += 2; \
+  } else { \
+    *cp++ = (u_char)(n); \
+  } \
+}
+
+#define DECODEL(f) { \
+  if (*cp == 0) {\
+    u32_t tmp = ntohl(f) + ((cp[1] << 8) | cp[2]); \
+    (f) = htonl(tmp); \
+    cp += 3; \
+  } else { \
+    u32_t tmp = ntohl(f) + (u32_t)*cp++; \
+    (f) = htonl(tmp); \
+  } \
+}
+
+#define DECODES(f) { \
+  if (*cp == 0) {\
+    u_short tmp = ntohs(f) + (((u_short)cp[1] << 8) | cp[2]); \
+    (f) = htons(tmp); \
+    cp += 3; \
+  } else { \
+    u_short tmp = ntohs(f) + (u_short)*cp++; \
+    (f) = htons(tmp); \
+  } \
+}
+
+#define DECODEU(f) { \
+  if (*cp == 0) {\
+    (f) = htons(((u_short)cp[1] << 8) | cp[2]); \
+    cp += 3; \
+  } else { \
+    (f) = htons((u_short)*cp++); \
+  } \
+}
+
+/*
+ * vj_compress_tcp - Attempt to do Van Jacobson header compression on a
+ * packet.  This assumes that nb and comp are not null and that the first
+ * buffer of the chain contains a valid IP header.
+ * Return the VJ type code indicating whether or not the packet was
+ * compressed.
+ */
+u_int
+vj_compress_tcp(struct vjcompress *comp, struct pbuf *pb)
+{
+  register struct ip_hdr *ip = (struct ip_hdr *)pb->payload;
+  register struct cstate *cs = comp->last_cs->cs_next;
+  register u_short hlen = IPH_HL(ip);
+  register struct tcp_hdr *oth;
+  register struct tcp_hdr *th;
+  register u_short deltaS, deltaA;
+  register u_long deltaL;
+  register u_int changes = 0;
+  u_char new_seq[16];
+  register u_char *cp = new_seq;
+
+  /*  
+   * Check that the packet is IP proto TCP.
+   */
+  if (IPH_PROTO(ip) != IP_PROTO_TCP) {
+    return (TYPE_IP);
+  }
+
+  /*
+   * Bail if this is an IP fragment or if the TCP packet isn't
+   * `compressible' (i.e., ACK isn't set or some other control bit is
+   * set).  
+   */
+  if ((IPH_OFFSET(ip) & PP_HTONS(0x3fff)) || pb->tot_len < 40) {
+    return (TYPE_IP);
+  }
+  th = (struct tcp_hdr *)&((long *)ip)[hlen];
+  if ((TCPH_FLAGS(th) & (TCP_SYN|TCP_FIN|TCP_RST|TCP_ACK)) != TCP_ACK) {
+    return (TYPE_IP);
+  }
+  /*
+   * Packet is compressible -- we're going to send either a
+   * COMPRESSED_TCP or UNCOMPRESSED_TCP packet.  Either way we need
+   * to locate (or create) the connection state.  Special case the
+   * most recently used connection since it's most likely to be used
+   * again & we don't have to do any reordering if it's used.
+   */
+  INCR(vjs_packets);
+  if (!ip_addr_cmp(&ip->src, &cs->cs_ip.src)
+      || !ip_addr_cmp(&ip->dest, &cs->cs_ip.dest)
+      || *(long *)th != ((long *)&cs->cs_ip)[IPH_HL(&cs->cs_ip)]) {
+    /*
+     * Wasn't the first -- search for it.
+     *
+     * States are kept in a circularly linked list with
+     * last_cs pointing to the end of the list.  The
+     * list is kept in lru order by moving a state to the
+     * head of the list whenever it is referenced.  Since
+     * the list is short and, empirically, the connection
+     * we want is almost always near the front, we locate
+     * states via linear search.  If we don't find a state
+     * for the datagram, the oldest state is (re-)used.
+     */
+    register struct cstate *lcs;
+    register struct cstate *lastcs = comp->last_cs;
+    
+    do {
+      lcs = cs; cs = cs->cs_next;
+      INCR(vjs_searches);
+      if (ip_addr_cmp(&ip->src, &cs->cs_ip.src)
+          && ip_addr_cmp(&ip->dest, &cs->cs_ip.dest)
+          && *(long *)th == ((long *)&cs->cs_ip)[IPH_HL(&cs->cs_ip)]) {
+        goto found;
+      }
+    } while (cs != lastcs);
+
+    /*
+     * Didn't find it -- re-use oldest cstate.  Send an
+     * uncompressed packet that tells the other side what
+     * connection number we're using for this conversation.
+     * Note that since the state list is circular, the oldest
+     * state points to the newest and we only need to set
+     * last_cs to update the lru linkage.
+     */
+    INCR(vjs_misses);
+    comp->last_cs = lcs;
+    hlen += TCPH_OFFSET(th);
+    hlen <<= 2;
+    /* Check that the IP/TCP headers are contained in the first buffer. */
+    if (hlen > pb->len) {
+      return (TYPE_IP);
+    }
+    goto uncompressed;
+
+    found:
+    /*
+     * Found it -- move to the front on the connection list.
+     */
+    if (cs == lastcs) {
+      comp->last_cs = lcs;
+    } else {
+      lcs->cs_next = cs->cs_next;
+      cs->cs_next = lastcs->cs_next;
+      lastcs->cs_next = cs;
+    }
+  }
+
+  oth = (struct tcp_hdr *)&((long *)&cs->cs_ip)[hlen];
+  deltaS = hlen;
+  hlen += TCPH_OFFSET(th);
+  hlen <<= 2;
+  /* Check that the IP/TCP headers are contained in the first buffer. */
+  if (hlen > pb->len) {
+    PPPDEBUG(LOG_INFO, ("vj_compress_tcp: header len %d spans buffers\n", hlen));
+    return (TYPE_IP);
+  }
+
+  /*
+   * Make sure that only what we expect to change changed. The first
+   * line of the `if' checks the IP protocol version, header length &
+   * type of service.  The 2nd line checks the "Don't fragment" bit.
+   * The 3rd line checks the time-to-live and protocol (the protocol
+   * check is unnecessary but costless).  The 4th line checks the TCP
+   * header length.  The 5th line checks IP options, if any.  The 6th
+   * line checks TCP options, if any.  If any of these things are
+   * different between the previous & current datagram, we send the
+   * current datagram `uncompressed'.
+   */
+  if (((u_short *)ip)[0] != ((u_short *)&cs->cs_ip)[0] 
+      || ((u_short *)ip)[3] != ((u_short *)&cs->cs_ip)[3] 
+      || ((u_short *)ip)[4] != ((u_short *)&cs->cs_ip)[4] 
+      || TCPH_OFFSET(th) != TCPH_OFFSET(oth) 
+      || (deltaS > 5 && BCMP(ip + 1, &cs->cs_ip + 1, (deltaS - 5) << 2)) 
+      || (TCPH_OFFSET(th) > 5 && BCMP(th + 1, oth + 1, (TCPH_OFFSET(th) - 5) << 2))) {
+    goto uncompressed;
+  }
+
+  /*
+   * Figure out which of the changing fields changed.  The
+   * receiver expects changes in the order: urgent, window,
+   * ack, seq (the order minimizes the number of temporaries
+   * needed in this section of code).
+   */
+  if (TCPH_FLAGS(th) & TCP_URG) {
+    deltaS = ntohs(th->urgp);
+    ENCODEZ(deltaS);
+    changes |= NEW_U;
+  } else if (th->urgp != oth->urgp) {
+    /* argh! URG not set but urp changed -- a sensible
+     * implementation should never do this but RFC793
+     * doesn't prohibit the change so we have to deal
+     * with it. */
+    goto uncompressed;
+  }
+
+  if ((deltaS = (u_short)(ntohs(th->wnd) - ntohs(oth->wnd))) != 0) {
+    ENCODE(deltaS);
+    changes |= NEW_W;
+  }
+
+  if ((deltaL = ntohl(th->ackno) - ntohl(oth->ackno)) != 0) {
+    if (deltaL > 0xffff) {
+      goto uncompressed;
+    }
+    deltaA = (u_short)deltaL;
+    ENCODE(deltaA);
+    changes |= NEW_A;
+  }
+
+  if ((deltaL = ntohl(th->seqno) - ntohl(oth->seqno)) != 0) {
+    if (deltaL > 0xffff) {
+      goto uncompressed;
+    }
+    deltaS = (u_short)deltaL;
+    ENCODE(deltaS);
+    changes |= NEW_S;
+  }
+
+  switch(changes) {
+  case 0:
+    /*
+     * Nothing changed. If this packet contains data and the
+     * last one didn't, this is probably a data packet following
+     * an ack (normal on an interactive connection) and we send
+     * it compressed.  Otherwise it's probably a retransmit,
+     * retransmitted ack or window probe.  Send it uncompressed
+     * in case the other side missed the compressed version.
+     */
+    if (IPH_LEN(ip) != IPH_LEN(&cs->cs_ip) &&
+      ntohs(IPH_LEN(&cs->cs_ip)) == hlen) {
+      break;
+    }
+
+  /* (fall through) */
+
+  case SPECIAL_I:
+  case SPECIAL_D:
+    /*
+     * actual changes match one of our special case encodings --
+     * send packet uncompressed.
+     */
+    goto uncompressed;
+
+  case NEW_S|NEW_A:
+    if (deltaS == deltaA && deltaS == ntohs(IPH_LEN(&cs->cs_ip)) - hlen) {
+      /* special case for echoed terminal traffic */
+      changes = SPECIAL_I;
+      cp = new_seq;
+    }
+    break;
+
+  case NEW_S:
+    if (deltaS == ntohs(IPH_LEN(&cs->cs_ip)) - hlen) {
+      /* special case for data xfer */
+      changes = SPECIAL_D;
+      cp = new_seq;
+    }
+    break;
+  }
+
+  deltaS = (u_short)(ntohs(IPH_ID(ip)) - ntohs(IPH_ID(&cs->cs_ip)));
+  if (deltaS != 1) {
+    ENCODEZ(deltaS);
+    changes |= NEW_I;
+  }
+  if (TCPH_FLAGS(th) & TCP_PSH) {
+    changes |= TCP_PUSH_BIT;
+  }
+  /*
+   * Grab the cksum before we overwrite it below.  Then update our
+   * state with this packet's header.
+   */
+  deltaA = ntohs(th->chksum);
+  BCOPY(ip, &cs->cs_ip, hlen);
+
+  /*
+   * We want to use the original packet as our compressed packet.
+   * (cp - new_seq) is the number of bytes we need for compressed
+   * sequence numbers.  In addition we need one byte for the change
+   * mask, one for the connection id and two for the tcp checksum.
+   * So, (cp - new_seq) + 4 bytes of header are needed.  hlen is how
+   * many bytes of the original packet to toss so subtract the two to
+   * get the new packet size.
+   */
+  deltaS = (u_short)(cp - new_seq);
+  if (!comp->compressSlot || comp->last_xmit != cs->cs_id) {
+    comp->last_xmit = cs->cs_id;
+    hlen -= deltaS + 4;
+    if(pbuf_header(pb, -hlen)){
+      /* Can we cope with this failing?  Just assert for now */
+      LWIP_ASSERT("pbuf_header failed\n", 0);
+    }
+    cp = (u_char *)pb->payload;
+    *cp++ = (u_char)(changes | NEW_C);
+    *cp++ = cs->cs_id;
+  } else {
+    hlen -= deltaS + 3;
+    if(pbuf_header(pb, -hlen)) {
+      /* Can we cope with this failing?  Just assert for now */
+      LWIP_ASSERT("pbuf_header failed\n", 0);
+    }
+    cp = (u_char *)pb->payload;
+    *cp++ = (u_char)changes;
+  }
+  *cp++ = (u_char)(deltaA >> 8);
+  *cp++ = (u_char)deltaA;
+  BCOPY(new_seq, cp, deltaS);
+  INCR(vjs_compressed);
+  return (TYPE_COMPRESSED_TCP);
+
+  /*
+   * Update connection state cs & send uncompressed packet (that is,
+   * a regular ip/tcp packet but with the 'conversation id' we hope
+   * to use on future compressed packets in the protocol field).
+   */
+uncompressed:
+  BCOPY(ip, &cs->cs_ip, hlen);
+  IPH_PROTO_SET(ip, cs->cs_id);
+  comp->last_xmit = cs->cs_id;
+  return (TYPE_UNCOMPRESSED_TCP);
+}
+
+/*
+ * Called when we may have missed a packet.
+ */
+void
+vj_uncompress_err(struct vjcompress *comp)
+{
+  comp->flags |= VJF_TOSS;
+  INCR(vjs_errorin);
+}
+
+/*
+ * "Uncompress" a packet of type TYPE_UNCOMPRESSED_TCP.
+ * Return 0 on success, -1 on failure.
+ */
+int
+vj_uncompress_uncomp(struct pbuf *nb, struct vjcompress *comp)
+{
+  register u_int hlen;
+  register struct cstate *cs;
+  register struct ip_hdr *ip;
+  
+  ip = (struct ip_hdr *)nb->payload;
+  hlen = IPH_HL(ip) << 2;
+  if (IPH_PROTO(ip) >= MAX_SLOTS
+      || hlen + sizeof(struct tcp_hdr) > nb->len
+      || (hlen += TCPH_OFFSET(((struct tcp_hdr *)&((char *)ip)[hlen])) << 2)
+          > nb->len
+      || hlen > MAX_HDR) {
+    PPPDEBUG(LOG_INFO, ("vj_uncompress_uncomp: bad cid=%d, hlen=%d buflen=%d\n", 
+      IPH_PROTO(ip), hlen, nb->len));
+    comp->flags |= VJF_TOSS;
+    INCR(vjs_errorin);
+    return -1;
+  }
+  cs = &comp->rstate[comp->last_recv = IPH_PROTO(ip)];
+  comp->flags &=~ VJF_TOSS;
+  IPH_PROTO_SET(ip, IP_PROTO_TCP);
+  BCOPY(ip, &cs->cs_ip, hlen);
+  cs->cs_hlen = (u_short)hlen;
+  INCR(vjs_uncompressedin);
+  return 0;
+}
+
+/*
+ * Uncompress a packet of type TYPE_COMPRESSED_TCP.
+ * The packet is composed of a buffer chain and the first buffer
+ * must contain an accurate chain length.
+ * The first buffer must include the entire compressed TCP/IP header. 
+ * This procedure replaces the compressed header with the uncompressed
+ * header and returns the length of the VJ header.
+ */
+int
+vj_uncompress_tcp(struct pbuf **nb, struct vjcompress *comp)
+{
+  u_char *cp;
+  struct tcp_hdr *th;
+  struct cstate *cs;
+  u_short *bp;
+  struct pbuf *n0 = *nb;
+  u32_t tmp;
+  u_int vjlen, hlen, changes;
+
+  INCR(vjs_compressedin);
+  cp = (u_char *)n0->payload;
+  changes = *cp++;
+  if (changes & NEW_C) {
+    /* 
+     * Make sure the state index is in range, then grab the state.
+     * If we have a good state index, clear the 'discard' flag. 
+     */
+    if (*cp >= MAX_SLOTS) {
+      PPPDEBUG(LOG_INFO, ("vj_uncompress_tcp: bad cid=%d\n", *cp));
+      goto bad;
+    }
+
+    comp->flags &=~ VJF_TOSS;
+    comp->last_recv = *cp++;
+  } else {
+    /* 
+     * this packet has an implicit state index.  If we've
+     * had a line error since the last time we got an
+     * explicit state index, we have to toss the packet. 
+     */
+    if (comp->flags & VJF_TOSS) {
+      PPPDEBUG(LOG_INFO, ("vj_uncompress_tcp: tossing\n"));
+      INCR(vjs_tossed);
+      return (-1);
+    }
+  }
+  cs = &comp->rstate[comp->last_recv];
+  hlen = IPH_HL(&cs->cs_ip) << 2;
+  th = (struct tcp_hdr *)&((u_char *)&cs->cs_ip)[hlen];
+  th->chksum = htons((*cp << 8) | cp[1]);
+  cp += 2;
+  if (changes & TCP_PUSH_BIT) {
+    TCPH_SET_FLAG(th, TCP_PSH);
+  } else {
+    TCPH_UNSET_FLAG(th, TCP_PSH);
+  }
+
+  switch (changes & SPECIALS_MASK) {
+  case SPECIAL_I:
+    {
+      register u32_t i = ntohs(IPH_LEN(&cs->cs_ip)) - cs->cs_hlen;
+      /* some compilers can't nest inline assembler.. */
+      tmp = ntohl(th->ackno) + i;
+      th->ackno = htonl(tmp);
+      tmp = ntohl(th->seqno) + i;
+      th->seqno = htonl(tmp);
+    }
+    break;
+
+  case SPECIAL_D:
+    /* some compilers can't nest inline assembler.. */
+    tmp = ntohl(th->seqno) + ntohs(IPH_LEN(&cs->cs_ip)) - cs->cs_hlen;
+    th->seqno = htonl(tmp);
+    break;
+
+  default:
+    if (changes & NEW_U) {
+      TCPH_SET_FLAG(th, TCP_URG);
+      DECODEU(th->urgp);
+    } else {
+      TCPH_UNSET_FLAG(th, TCP_URG);
+    }
+    if (changes & NEW_W) {
+      DECODES(th->wnd);
+    }
+    if (changes & NEW_A) {
+      DECODEL(th->ackno);
+    }
+    if (changes & NEW_S) {
+      DECODEL(th->seqno);
+    }
+    break;
+  }
+  if (changes & NEW_I) {
+    DECODES(cs->cs_ip._id);
+  } else {
+    IPH_ID_SET(&cs->cs_ip, ntohs(IPH_ID(&cs->cs_ip)) + 1);
+    IPH_ID_SET(&cs->cs_ip, htons(IPH_ID(&cs->cs_ip)));
+  }
+
+  /*
+   * At this point, cp points to the first byte of data in the
+   * packet.  Fill in the IP total length and update the IP
+   * header checksum.
+   */
+  vjlen = (u_short)(cp - (u_char*)n0->payload);
+  if (n0->len < vjlen) {
+    /* 
+     * We must have dropped some characters (crc should detect
+     * this but the old slip framing won't) 
+     */
+    PPPDEBUG(LOG_INFO, ("vj_uncompress_tcp: head buffer %d too short %d\n", 
+          n0->len, vjlen));
+    goto bad;
+  }
+
+#if BYTE_ORDER == LITTLE_ENDIAN
+  tmp = n0->tot_len - vjlen + cs->cs_hlen;
+  IPH_LEN_SET(&cs->cs_ip, htons((u_short)tmp));
+#else
+  IPH_LEN_SET(&cs->cs_ip, htons(n0->tot_len - vjlen + cs->cs_hlen));
+#endif
+
+  /* recompute the ip header checksum */
+  bp = (u_short *) &cs->cs_ip;
+  IPH_CHKSUM_SET(&cs->cs_ip, 0);
+  for (tmp = 0; hlen > 0; hlen -= 2) {
+    tmp += *bp++;
+  }
+  tmp = (tmp & 0xffff) + (tmp >> 16);
+  tmp = (tmp & 0xffff) + (tmp >> 16);
+  IPH_CHKSUM_SET(&cs->cs_ip,  (u_short)(~tmp));
+  
+  /* Remove the compressed header and prepend the uncompressed header. */
+  if(pbuf_header(n0, -((s16_t)(vjlen)))) {
+    /* Can we cope with this failing?  Just assert for now */
+    LWIP_ASSERT("pbuf_header failed\n", 0);
+    goto bad;
+  }
+
+  if(LWIP_MEM_ALIGN(n0->payload) != n0->payload) {
+    struct pbuf *np, *q;
+    u8_t *bufptr;
+
+    np = pbuf_alloc(PBUF_RAW, n0->len + cs->cs_hlen, PBUF_POOL);
+    if(!np) {
+      PPPDEBUG(LOG_WARNING, ("vj_uncompress_tcp: realign failed\n"));
+      goto bad;
+    }
+
+    if(pbuf_header(np, -cs->cs_hlen)) {
+      /* Can we cope with this failing?  Just assert for now */
+      LWIP_ASSERT("pbuf_header failed\n", 0);
+      goto bad;
+    }
+
+    bufptr = n0->payload;
+    for(q = np; q != NULL; q = q->next) {
+      MEMCPY(q->payload, bufptr, q->len);
+      bufptr += q->len;
+    }
+
+    if(n0->next) {
+      pbuf_chain(np, n0->next);
+      pbuf_dechain(n0);
+    }
+    pbuf_free(n0);
+    n0 = np;
+  }
+
+  if(pbuf_header(n0, cs->cs_hlen)) {
+    struct pbuf *np;
+
+    LWIP_ASSERT("vj_uncompress_tcp: cs->cs_hlen <= PBUF_POOL_BUFSIZE", cs->cs_hlen <= PBUF_POOL_BUFSIZE);
+    np = pbuf_alloc(PBUF_RAW, cs->cs_hlen, PBUF_POOL);
+    if(!np) {
+      PPPDEBUG(LOG_WARNING, ("vj_uncompress_tcp: prepend failed\n"));
+      goto bad;
+    }
+    pbuf_cat(np, n0);
+    n0 = np;
+  }
+  LWIP_ASSERT("n0->len >= cs->cs_hlen", n0->len >= cs->cs_hlen);
+  MEMCPY(n0->payload, &cs->cs_ip, cs->cs_hlen);
+
+  *nb = n0;
+
+  return vjlen;
+
+bad:
+  comp->flags |= VJF_TOSS;
+  INCR(vjs_errorin);
+  return (-1);
+}
+
+#endif /* VJ_SUPPORT */
+
+#endif /* PPP_SUPPORT */
diff --git a/core/lwip/src/netif/ppp/vj.h b/core/lwip/src/netif/ppp/vj.h
new file mode 100644
index 00000000..fad12136
--- /dev/null
+++ b/core/lwip/src/netif/ppp/vj.h
@@ -0,0 +1,156 @@
+/*
+ * Definitions for tcp compression routines.
+ *
+ * $Id: vj.h,v 1.7 2010/02/22 17:52:09 goldsimon Exp $
+ *
+ * Copyright (c) 1989 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by the University of California, Berkeley.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989:
+ * - Initial distribution.
+ */
+
+#ifndef VJ_H
+#define VJ_H
+
+#include "lwip/ip.h"
+#include "lwip/tcp_impl.h"
+
+#define MAX_SLOTS 16 /* must be > 2 and < 256 */
+#define MAX_HDR   128
+
+/*
+ * Compressed packet format:
+ *
+ * The first octet contains the packet type (top 3 bits), TCP
+ * 'push' bit, and flags that indicate which of the 4 TCP sequence
+ * numbers have changed (bottom 5 bits).  The next octet is a
+ * conversation number that associates a saved IP/TCP header with
+ * the compressed packet.  The next two octets are the TCP checksum
+ * from the original datagram.  The next 0 to 15 octets are
+ * sequence number changes, one change per bit set in the header
+ * (there may be no changes and there are two special cases where
+ * the receiver implicitly knows what changed -- see below).
+ * 
+ * There are 5 numbers which can change (they are always inserted
+ * in the following order): TCP urgent pointer, window,
+ * acknowlegement, sequence number and IP ID.  (The urgent pointer
+ * is different from the others in that its value is sent, not the
+ * change in value.)  Since typical use of SLIP links is biased
+ * toward small packets (see comments on MTU/MSS below), changes
+ * use a variable length coding with one octet for numbers in the
+ * range 1 - 255 and 3 octets (0, MSB, LSB) for numbers in the
+ * range 256 - 65535 or 0.  (If the change in sequence number or
+ * ack is more than 65535, an uncompressed packet is sent.)
+ */
+
+/*
+ * Packet types (must not conflict with IP protocol version)
+ *
+ * The top nibble of the first octet is the packet type.  There are
+ * three possible types: IP (not proto TCP or tcp with one of the
+ * control flags set); uncompressed TCP (a normal IP/TCP packet but
+ * with the 8-bit protocol field replaced by an 8-bit connection id --
+ * this type of packet syncs the sender & receiver); and compressed
+ * TCP (described above).
+ *
+ * LSB of 4-bit field is TCP "PUSH" bit (a worthless anachronism) and
+ * is logically part of the 4-bit "changes" field that follows.  Top
+ * three bits are actual packet type.  For backward compatibility
+ * and in the interest of conserving bits, numbers are chosen so the
+ * IP protocol version number (4) which normally appears in this nibble
+ * means "IP packet".
+ */
+
+/* packet types */
+#define TYPE_IP               0x40
+#define TYPE_UNCOMPRESSED_TCP 0x70
+#define TYPE_COMPRESSED_TCP   0x80
+#define TYPE_ERROR            0x00
+
+/* Bits in first octet of compressed packet */
+#define NEW_C 0x40 /* flag bits for what changed in a packet */
+#define NEW_I 0x20
+#define NEW_S 0x08
+#define NEW_A 0x04
+#define NEW_W 0x02
+#define NEW_U 0x01
+
+/* reserved, special-case values of above */
+#define SPECIAL_I (NEW_S|NEW_W|NEW_U) /* echoed interactive traffic */
+#define SPECIAL_D (NEW_S|NEW_A|NEW_W|NEW_U) /* unidirectional data */
+#define SPECIALS_MASK (NEW_S|NEW_A|NEW_W|NEW_U)
+
+#define TCP_PUSH_BIT 0x10
+
+
+/*
+ * "state" data for each active tcp conversation on the wire.  This is
+ * basically a copy of the entire IP/TCP header from the last packet
+ * we saw from the conversation together with a small identifier
+ * the transmit & receive ends of the line use to locate saved header.
+ */
+struct cstate {
+  struct cstate *cs_next; /* next most recently used state (xmit only) */
+  u_short cs_hlen;        /* size of hdr (receive only) */
+  u_char cs_id;           /* connection # associated with this state */
+  u_char cs_filler;
+  union {
+    char csu_hdr[MAX_HDR];
+    struct ip_hdr csu_ip;     /* ip/tcp hdr from most recent packet */
+  } vjcs_u;
+};
+#define cs_ip vjcs_u.csu_ip
+#define cs_hdr vjcs_u.csu_hdr
+
+
+struct vjstat {
+  unsigned long vjs_packets;        /* outbound packets */
+  unsigned long vjs_compressed;     /* outbound compressed packets */
+  unsigned long vjs_searches;       /* searches for connection state */
+  unsigned long vjs_misses;         /* times couldn't find conn. state */
+  unsigned long vjs_uncompressedin; /* inbound uncompressed packets */
+  unsigned long vjs_compressedin;   /* inbound compressed packets */
+  unsigned long vjs_errorin;        /* inbound unknown type packets */
+  unsigned long vjs_tossed;         /* inbound packets tossed because of error */
+};
+
+/*
+ * all the state data for one serial line (we need one of these per line).
+ */
+struct vjcompress {
+  struct cstate *last_cs;          /* most recently used tstate */
+  u_char last_recv;                /* last rcvd conn. id */
+  u_char last_xmit;                /* last sent conn. id */
+  u_short flags;
+  u_char maxSlotIndex;
+  u_char compressSlot;             /* Flag indicating OK to compress slot ID. */
+#if LINK_STATS
+  struct vjstat stats;
+#endif
+  struct cstate tstate[MAX_SLOTS]; /* xmit connection states */
+  struct cstate rstate[MAX_SLOTS]; /* receive connection states */
+};
+
+/* flag values */
+#define VJF_TOSS 1U /* tossing rcvd frames because of input err */
+
+extern void  vj_compress_init    (struct vjcompress *comp);
+extern u_int vj_compress_tcp     (struct vjcompress *comp, struct pbuf *pb);
+extern void  vj_uncompress_err   (struct vjcompress *comp);
+extern int   vj_uncompress_uncomp(struct pbuf *nb, struct vjcompress *comp);
+extern int   vj_uncompress_tcp   (struct pbuf **nb, struct vjcompress *comp);
+
+#endif /* VJ_H */
diff --git a/core/lwip/src/netif/slipif.c b/core/lwip/src/netif/slipif.c
new file mode 100644
index 00000000..c19333dd
--- /dev/null
+++ b/core/lwip/src/netif/slipif.c
@@ -0,0 +1,367 @@
+/**
+ * @file
+ * SLIP Interface
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ *
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions 
+ * are met: 
+ * 1. Redistributions of source code must retain the above copyright 
+ *    notice, this list of conditions and the following disclaimer. 
+ * 2. Redistributions in binary form must reproduce the above copyright 
+ *    notice, this list of conditions and the following disclaimer in the 
+ *    documentation and/or other materials provided with the distribution. 
+ * 3. Neither the name of the Institute nor the names of its contributors 
+ *    may be used to endorse or promote products derived from this software 
+ *    without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
+ * SUCH DAMAGE. 
+ *
+ * This file is built upon the file: src/arch/rtxc/netif/sioslip.c
+ *
+ * Author: Magnus Ivarsson <magnus.ivarsson(at)volvo.com> 
+ */
+
+/* 
+ * This is an arch independent SLIP netif. The specific serial hooks must be
+ * provided by another file. They are sio_open, sio_read/sio_tryread and sio_send
+ */
+
+#include "netif/slipif.h"
+#include "lwip/opt.h"
+
+#if LWIP_HAVE_SLIPIF
+
+#include "lwip/def.h"
+#include "lwip/pbuf.h"
+#include "lwip/sys.h"
+#include "lwip/stats.h"
+#include "lwip/snmp.h"
+#include "lwip/sio.h"
+
+#define SLIP_BLOCK     1
+#define SLIP_DONTBLOCK 0
+
+#define SLIP_END     0300 /* 0xC0 */
+#define SLIP_ESC     0333 /* 0xDB */
+#define SLIP_ESC_END 0334 /* 0xDC */
+#define SLIP_ESC_ESC 0335 /* 0xDD */
+
+#define SLIP_MAX_SIZE 1500
+
+enum slipif_recv_state {
+    SLIP_RECV_NORMAL,
+    SLIP_RECV_ESCAPE,
+};
+
+struct slipif_priv {
+  sio_fd_t sd;
+  /* q is the whole pbuf chain for a packet, p is the current pbuf in the chain */
+  struct pbuf *p, *q;
+  enum slipif_recv_state state;
+  u16_t i, recved;
+};
+
+/**
+ * Send a pbuf doing the necessary SLIP encapsulation
+ *
+ * Uses the serial layer's sio_send()
+ *
+ * @param netif the lwip network interface structure for this slipif
+ * @param p the pbuf chaing packet to send
+ * @param ipaddr the ip address to send the packet to (not used for slipif)
+ * @return always returns ERR_OK since the serial layer does not provide return values
+ */
+err_t
+slipif_output(struct netif *netif, struct pbuf *p, ip_addr_t *ipaddr)
+{
+  struct slipif_priv *priv;
+  struct pbuf *q;
+  u16_t i;
+  u8_t c;
+
+  LWIP_ASSERT("netif != NULL", (netif != NULL));
+  LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
+  LWIP_ASSERT("p != NULL", (p != NULL));
+
+  LWIP_UNUSED_ARG(ipaddr);
+
+  priv = netif->state;
+
+  /* Send pbuf out on the serial I/O device. */
+  sio_send(SLIP_END, priv->sd);
+
+  for (q = p; q != NULL; q = q->next) {
+    for (i = 0; i < q->len; i++) {
+      c = ((u8_t *)q->payload)[i];
+      switch (c) {
+      case SLIP_END:
+        sio_send(SLIP_ESC, priv->sd);
+        sio_send(SLIP_ESC_END, priv->sd);
+        break;
+      case SLIP_ESC:
+        sio_send(SLIP_ESC, priv->sd);
+        sio_send(SLIP_ESC_ESC, priv->sd);
+        break;
+      default:
+        sio_send(c, priv->sd);
+        break;
+      }
+    }
+  }
+  sio_send(SLIP_END, priv->sd);
+  return ERR_OK;
+}
+
+/**
+ * Static function for easy use of blockig or non-blocking
+ * sio_read
+ *
+ * @param fd serial device handle
+ * @param data pointer to data buffer for receiving
+ * @param len maximum length (in bytes) of data to receive
+ * @param block if 1, call sio_read; if 0, call sio_tryread
+ * @return return value of sio_read of sio_tryread
+ */
+static u32_t
+slip_sio_read(sio_fd_t fd, u8_t* data, u32_t len, u8_t block)
+{
+  if (block) {
+    return sio_read(fd, data, len);
+  } else {
+    return sio_tryread(fd, data, len);
+  }
+}
+
+/**
+ * Handle the incoming SLIP stream character by character
+ *
+ * Poll the serial layer by calling sio_read() or sio_tryread().
+ *
+ * @param netif the lwip network interface structure for this slipif
+ * @param block if 1, block until data is received; if 0, return when all data
+ *        from the buffer is received (multiple calls to this function will
+ *        return a complete packet, NULL is returned before - used for polling)
+ * @return The IP packet when SLIP_END is received
+ */
+static struct pbuf *
+slipif_input(struct netif *netif, u8_t block)
+{
+  struct slipif_priv *priv;
+  u8_t c;
+  struct pbuf *t;
+
+  LWIP_ASSERT("netif != NULL", (netif != NULL));
+  LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
+
+  priv = netif->state;
+
+  while (slip_sio_read(priv->sd, &c, 1, block) > 0) {
+    switch (priv->state) {
+    case SLIP_RECV_NORMAL:
+      switch (c) {
+      case SLIP_END:
+        if (priv->recved > 0) {
+          /* Received whole packet. */
+          /* Trim the pbuf to the size of the received packet. */
+          pbuf_realloc(priv->q, priv->recved);
+
+          LINK_STATS_INC(link.recv);
+
+          LWIP_DEBUGF(SLIP_DEBUG, ("slipif: Got packet\n"));
+          t = priv->q;
+          priv->p = priv->q = NULL;
+          priv->i = priv->recved = 0;
+          return t;
+        }
+        continue;
+      case SLIP_ESC:
+        priv->state = SLIP_RECV_ESCAPE;
+        continue;
+      }
+      break;
+    case SLIP_RECV_ESCAPE:
+      switch (c) {
+      case SLIP_ESC_END:
+        c = SLIP_END;
+        break;
+      case SLIP_ESC_ESC:
+        c = SLIP_ESC;
+        break;
+      }
+      priv->state = SLIP_RECV_NORMAL;
+      /* FALLTHROUGH */
+    }
+
+    /* byte received, packet not yet completely received */
+    if (priv->p == NULL) {
+      /* allocate a new pbuf */
+      LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: alloc\n"));
+      priv->p = pbuf_alloc(PBUF_LINK, (PBUF_POOL_BUFSIZE - PBUF_LINK_HLEN), PBUF_POOL);
+
+      if (priv->p == NULL) {
+        LINK_STATS_INC(link.drop);
+        LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: no new pbuf! (DROP)\n"));
+        /* don't process any further since we got no pbuf to receive to */
+        break;
+      }
+
+      if (priv->q != NULL) {
+        /* 'chain' the pbuf to the existing chain */
+        pbuf_cat(priv->q, priv->p);
+      } else {
+        /* p is the first pbuf in the chain */
+        priv->q = priv->p;
+      }
+    }
+
+    /* this automatically drops bytes if > SLIP_MAX_SIZE */
+    if ((priv->p != NULL) && (priv->recved <= SLIP_MAX_SIZE)) {
+      ((u8_t *)priv->p->payload)[priv->i] = c;
+      priv->recved++;
+      priv->i++;
+      if (priv->i >= priv->p->len) {
+        /* on to the next pbuf */
+        priv->i = 0;
+        if (priv->p->next != NULL && priv->p->next->len > 0) {
+          /* p is a chain, on to the next in the chain */
+            priv->p = priv->p->next;
+        } else {
+          /* p is a single pbuf, set it to NULL so next time a new
+           * pbuf is allocated */
+            priv->p = NULL;
+        }
+      }
+    }
+  }
+
+  return NULL;
+}
+
+#if !NO_SYS
+/**
+ * The SLIP input thread.
+ *
+ * Feed the IP layer with incoming packets
+ *
+ * @param nf the lwip network interface structure for this slipif
+ */
+static void
+slipif_loop_thread(void *nf)
+{
+  struct pbuf *p;
+  struct netif *netif = (struct netif *)nf;
+
+  while (1) {
+    p = slipif_input(netif, SLIP_BLOCK);
+    if (p != NULL) {
+      if (netif->input(p, netif) != ERR_OK) {
+        pbuf_free(p);
+        p = NULL;
+      }
+    }
+  }
+}
+#endif /* !NO_SYS */
+
+/**
+ * SLIP netif initialization
+ *
+ * Call the arch specific sio_open and remember
+ * the opened device in the state field of the netif.
+ *
+ * @param netif the lwip network interface structure for this slipif
+ * @return ERR_OK if serial line could be opened,
+ *         ERR_MEM if no memory could be allocated,
+ *         ERR_IF is serial line couldn't be opened
+ *
+ * @note netif->num must contain the number of the serial port to open
+ *       (0 by default)
+ */
+err_t
+slipif_init(struct netif *netif)
+{
+  struct slipif_priv *priv;
+
+  LWIP_DEBUGF(SLIP_DEBUG, ("slipif_init: netif->num=%"U16_F"\n", (u16_t)netif->num));
+
+  /* Allocate private data */
+  priv = mem_malloc(sizeof(struct slipif_priv));
+  if (!priv) {
+    return ERR_MEM;
+  }
+
+  netif->name[0] = 's';
+  netif->name[1] = 'l';
+  netif->output = slipif_output;
+  netif->mtu = SLIP_MAX_SIZE;
+  netif->flags |= NETIF_FLAG_POINTTOPOINT;
+
+  /* Try to open the serial port (netif->num contains the port number). */
+  priv->sd = sio_open(netif->num);
+  if (!priv->sd) {
+    /* Opening the serial port failed. */
+    mem_free(priv);
+    return ERR_IF;
+  }
+
+  /* Initialize private data */
+  priv->p = NULL;
+  priv->q = NULL;
+  priv->state = SLIP_RECV_NORMAL;
+  priv->i = 0;
+  priv->recved = 0;
+
+  netif->state = priv;
+
+  /* initialize the snmp variables and counters inside the struct netif
+   * ifSpeed: no assumption can be made without knowing more about the
+   * serial line!
+   */
+  NETIF_INIT_SNMP(netif, snmp_ifType_slip, 0);
+
+  /* Create a thread to poll the serial line. */
+  sys_thread_new(SLIPIF_THREAD_NAME, slipif_loop_thread, netif,
+    SLIPIF_THREAD_STACKSIZE, SLIPIF_THREAD_PRIO);
+  return ERR_OK;
+}
+
+/**
+ * Polls the serial device and feeds the IP layer with incoming packets.
+ *
+ * @param netif The lwip network interface structure for this slipif
+ */
+void
+slipif_poll(struct netif *netif)
+{
+  struct pbuf *p;
+  struct slipif_priv *priv;
+
+  LWIP_ASSERT("netif != NULL", (netif != NULL));
+  LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
+
+  priv = netif->state;
+
+  while ((p = slipif_input(netif, SLIP_DONTBLOCK)) != NULL) {
+    if (netif->input(p, netif) != ERR_OK) {
+      pbuf_free(p);
+    }
+  }
+}
+
+#endif /* LWIP_HAVE_SLIPIF */
diff --git a/core/lwip/src/netif/undiif.c b/core/lwip/src/netif/undiif.c
new file mode 100644
index 00000000..2c7e4ac4
--- /dev/null
+++ b/core/lwip/src/netif/undiif.c
@@ -0,0 +1,1388 @@
+/**
+ * @file
+ * Ethernet Interface Skeleton
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ * Author: H. Peter Anvin <hpa@@zytor.com>
+ * Author: Eric Biederman <ebiederm@xmission.com>
+ *
+ */
+
+/*
+ * This file is a skeleton for developing Ethernet network interface
+ * drivers for lwIP. Add code to the low_level functions and do a
+ * search-and-replace for the word "ethernetif" to replace it with
+ * something that better describes your network interface.
+ */
+
+#include <core.h>
+
+#include "lwip/opt.h"
+
+#include "lwip/def.h"
+#include "lwip/mem.h"
+#include "lwip/pbuf.h"
+#include "lwip/sys.h"
+#include <lwip/stats.h>
+#include <lwip/snmp.h>
+#include "netif/etharp.h"
+#include "netif/ppp_oe.h"
+#include "lwip/netifapi.h"
+#include "lwip/tcpip.h"
+#include "../../../fs/pxe/pxe.h"
+
+#include <inttypes.h>
+#include <string.h>
+#include <syslinux/pxe_api.h>
+#include <dprintf.h>
+
+#if LWIP_AUTOIP
+#error "AUTOIP not supported"
+#endif
+#if ETH_PAD_SIZE
+#error "ETH_PAD_SIZE not supported"
+#endif
+#if NETIF_MAX_HWADDR_LEN != MAC_MAX
+#error "hwaddr_len mismatch"
+#endif
+
+/** the time an ARP entry stays valid after its last update,
+ *  for ARP_TMR_INTERVAL = 5000, this is
+ *  (240 * 5) seconds = 20 minutes.
+ */
+#define UNDIARP_MAXAGE 240
+/** the time an ARP entry stays pending after first request,
+ *  for ARP_TMR_INTERVAL = 5000, this is
+ *  (2 * 5) seconds = 10 seconds.
+ * 
+ *  @internal Keep this number at least 2, otherwise it might
+ *  run out instantly if the timeout occurs directly after a request.
+ */
+#define UNDIARP_MAXPENDING 2
+
+typedef u8_t hwaddr_t[NETIF_MAX_HWADDR_LEN];
+
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+/** the ARP message */
+struct arp_hdr {
+  PACK_STRUCT_FIELD(u16_t hwtype);
+  PACK_STRUCT_FIELD(u16_t proto);
+  PACK_STRUCT_FIELD(u16_t _hwlen_protolen);
+  PACK_STRUCT_FIELD(u16_t opcode);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+static inline int arp_hdr_len(struct netif *netif)
+{
+  return sizeof(struct arp_hdr) + (netif->hwaddr_len + sizeof(uint32_t))*2;
+}
+
+enum undiarp_state {
+  UNDIARP_STATE_EMPTY = 0,
+  UNDIARP_STATE_PENDING,
+  UNDIARP_STATE_STABLE
+};
+
+struct undiarp_entry {
+#if ARP_QUEUEING
+  /** 
+   * Pointer to queue of pending outgoing packets on this ARP entry.
+   */
+  struct etharp_q_entry *q;
+#endif
+  struct ip_addr ipaddr;
+  u8_t hwaddr[NETIF_MAX_HWADDR_LEN];
+  enum undiarp_state state;
+  u8_t ctime;
+  struct netif *netif;
+};
+
+#define PKTBUF_SIZE	2048
+
+/* Define those to better describe your network interface. */
+#define IFNAME0 'u'
+#define IFNAME1 'n'
+
+static struct netif undi_netif;
+static struct undiarp_entry arp_table[ARP_TABLE_SIZE];
+#if !LWIP_NETIF_HWADDRHINT
+static u8_t undiarp_cached_entry;
+#endif
+
+/**
+ * Try hard to create a new entry - we want the IP address to appear in
+ * the cache (even if this means removing an active entry or so). */
+#define UNDIARP_TRY_HARD 1
+#define UNDIARP_FIND_ONLY  2
+
+
+static inline bool undi_is_ethernet(struct netif *netif)
+{
+   (void)netif;
+   return MAC_type == ETHER_TYPE;
+}
+
+#if 0
+static void print_pbuf(struct pbuf *p)
+{
+   struct pbuf *q;
+   int off;
+
+   for( off = 0, q = p; q != NULL; q = q->next) {
+       unsigned char *byte, *end;
+       byte = q->payload;
+       end = byte + q->len;
+       for (; byte < end; byte++, off++ ) {
+	   if ((off & 0xf) == 0) {
+	       printf("%04x: ", off);
+	   }
+	   printf("%02x ", *byte);
+	   if ((off & 0xf) == 0xf) {
+	       printf("\n");
+	   }
+       }
+   }
+   printf("\n");
+}
+#endif
+
+#if 0
+static void print_arp_pbuf(struct netif *netif, struct pbuf *p)
+{
+  struct arp_hdr *hdr;
+  u8_t *hdr_ptr;
+  int i;
+
+  hdr = p->payload;
+  hdr_ptr = (unsigned char *)(hdr + 1);
+  /* Fixed fields */
+  printf("arp: %04x %04x %04x %04x ",
+	  hdr->hwtype,
+	  hdr->proto,
+	  hdr->_hwlen_protolen);
+  /* Source hardware address */
+  for(i = 0; i < netif->hwaddr_len; i++, hdr_ptr++) {
+    printf("%02x%c", *hdr_ptr,(i +1) == netif->hwaddr_len?' ':':');
+  }
+  /* Source ip address */
+  printf("%d.%d.%d.%d ", hdr_ptr[0], hdr_ptr[1], hdr_ptr[2], hdr_ptr[3]);
+  hdr_ptr += 4;
+  /* Destination hardware address */
+  for(i = 0; i < netif->hwaddr_len; i++, hdr_ptr++) {
+    printf("%02x%c", *hdr_ptr, (i +1) == netif->hwaddr_len?' ':':');
+  }
+  /* Destination ip address */
+  printf("%d.%d.%d.%d ", hdr_ptr[0], hdr_ptr[1], hdr_ptr[2], hdr_ptr[3]);
+  hdr_ptr += 4;
+}
+#endif
+
+/**
+ * In this function, the hardware should be initialized.
+ * Called from undiif_init().
+ *
+ * @param netif the already initialized lwip network interface structure
+ *        for this undiif
+ */
+static void
+low_level_init(struct netif *netif)
+{
+  static __lowmem t_PXENV_UNDI_OPEN undi_open;
+  int i;
+
+  /* MAC_type and MAC_len should always match what is returned by
+   * PXENV_UNDI_GET_INFORMATION.  At the moment the both seem to be
+   * reliable but if they disagree that is a sign of a nasty bug
+   * somewhere so abort.
+   */
+  /* If we are in conflict abort */
+  if (MAC_type != pxe_undi_info.HwType) {
+    printf("HwType conflicit: %u != %u\n",
+	    MAC_type, pxe_undi_info.HwType);
+    kaboom();
+  }
+  if (MAC_len != pxe_undi_info.HwAddrLen) {
+     printf("HwAddrLen conflict: %u != %u\n",
+	     MAC_len, pxe_undi_info.HwAddrLen);
+     kaboom();
+  }
+
+  /* set MAC hardware address length */
+  netif->hwaddr_len = MAC_len;
+
+  /* set MAC hardware address */
+  memcpy(netif->hwaddr, MAC, MAC_len);
+
+  /* maximum transfer unit */
+  netif->mtu = pxe_undi_info.MaxTranUnit;
+
+  dprintf("UNDI: hw address");
+  for (i = 0; i < netif->hwaddr_len; i++)
+      dprintf("%c%02x", i ? ':' : ' ', (uint8_t)netif->hwaddr[i]);
+  dprintf("\n");
+
+  /* device capabilities */
+  netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_LINK_UP;
+  /* don't set NETIF_FLAG_ETHARP if this device is not an ethernet one */
+  if (undi_is_ethernet(netif))
+    netif->flags |= NETIF_FLAG_ETHARP;
+
+  /* Install the interrupt vector */
+  pxe_start_isr();
+
+  /* Open the UNDI stack - you'd think the BC would have done this... */
+  undi_open.PktFilter = 0x0003;	/* FLTR_DIRECTED | FLTR_BRDCST */
+  pxe_call(PXENV_UNDI_OPEN, &undi_open);
+}
+
+/**
+ * This function should do the actual transmission of the packet. The packet is
+ * contained in the pbuf that is passed to the function. This pbuf
+ * might be chained.
+ *
+ * @param netif the lwip network interface structure for this undiif
+ * @param p the MAC packet to send (e.g. IP packet including MAC addresses and type)
+ * @return ERR_OK if the packet could be sent
+ *         an err_t value if the packet couldn't be sent
+ *
+ * @note Returning ERR_MEM here if a DMA queue of your MAC is full can lead to
+ *       strange results. You might consider waiting for space in the DMA queue
+ *       to become availale since the stack doesn't retry to send a packet
+ *       dropped because of memory failure (except for the TCP timers).
+ */
+extern volatile uint32_t pxe_irq_count;
+extern volatile uint8_t  pxe_need_poll;
+
+static err_t
+undi_transmit(struct netif *netif, struct pbuf *pbuf,
+  hwaddr_t *dest, uint16_t undi_protocol)
+{
+  struct pxe_xmit {
+    t_PXENV_UNDI_TRANSMIT xmit;
+    t_PXENV_UNDI_TBD tbd;
+  };
+  static __lowmem struct pxe_xmit pxe;
+  static __lowmem hwaddr_t low_dest;
+  static __lowmem char pkt_buf[PKTBUF_SIZE];
+  uint32_t now;
+  static uint32_t first_xmit;
+
+  /* Drop jumbo frames */
+  if ((pbuf->tot_len > sizeof(pkt_buf)) || (pbuf->tot_len > netif->mtu))
+    return ERR_ARG;
+
+  if (__unlikely(!pxe_irq_count)) {
+      now = ms_timer();
+      if (!first_xmit) {
+	  first_xmit = now;
+      } else if (now - first_xmit > 3000) {
+	  /* 3 seconds after first transmit, and no interrupts */
+	  asm volatile("orb $1,%0" : "+m" (pxe_need_poll));
+	  asm volatile("incl %0" : "+m" (pxe_irq_count));
+      }
+  }
+
+  pbuf_copy_partial( pbuf, pkt_buf, pbuf->tot_len, 0);
+  if (dest)
+    memcpy(low_dest, dest, netif->hwaddr_len);
+
+  do {
+    memset(&pxe, 0, sizeof pxe);
+
+    pxe.xmit.Protocol = undi_protocol;
+    pxe.xmit.XmitFlag = dest? XMT_DESTADDR : XMT_BROADCAST;
+    pxe.xmit.DestAddr = FAR_PTR(&low_dest);
+    pxe.xmit.TBD = FAR_PTR(&pxe.tbd);
+    pxe.tbd.ImmedLength = pbuf->tot_len;
+    pxe.tbd.Xmit = FAR_PTR(pkt_buf);
+
+    pxe_call(PXENV_UNDI_TRANSMIT, &pxe.xmit);
+  } while (pxe.xmit.Status == PXENV_STATUS_OUT_OF_RESOURCES);
+
+  LINK_STATS_INC(link.xmit);
+
+  return ERR_OK;
+}
+
+static err_t
+undi_send_unknown(struct netif *netif, struct pbuf *pbuf)
+{
+  return undi_transmit(netif, pbuf, NULL, P_UNKNOWN);
+}
+
+static err_t
+undi_send_ip(struct netif *netif, struct pbuf *pbuf, hwaddr_t  *dst)
+{
+  return undi_transmit(netif, pbuf, dst, P_IP);
+}
+
+static err_t
+undi_send_arp(struct netif *netif, struct pbuf *pbuf, hwaddr_t  *dst)
+{
+  return undi_transmit(netif, pbuf, dst, P_ARP);
+}
+
+/**
+ * Send an ARP request packet asking for ipaddr.
+ *
+ * @param netif the lwip network interface on which to send the request
+ * @param ipaddr the IP address for which to ask
+ * @return ERR_OK if the request has been sent
+ *         ERR_MEM if the ARP packet couldn't be allocated
+ *         any other err_t on failure
+ */
+static err_t
+undiarp_request(struct netif *netif, struct ip_addr *ipaddr)
+{
+  struct pbuf *p;
+  err_t result = ERR_OK;
+  struct arp_hdr *hdr;
+  u8_t *hdr_ptr;
+
+  LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_request: sending ARP request.\n"));
+
+  /* allocate a pbuf for the outgoing ARP request packet */
+  p = pbuf_alloc(PBUF_RAW, arp_hdr_len(netif), PBUF_RAM);
+  /* could allocate a pbuf for an ARP request? */
+  if (p == NULL) {
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
+      ("etharp_raw: could not allocate pbuf for ARP request.\n"));
+    ETHARP_STATS_INC(etharp.memerr);
+    return ERR_MEM;
+  }
+  LWIP_ASSERT("check that first pbuf can hold arp_hdr_len bytesr",
+              (p->len >= arp_hdr_len(netif)));
+
+  hdr = p->payload;
+  LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("undiarp_request: sending raw ARP packet.\n"));
+  hdr->opcode = htons(ARP_REQUEST);
+  hdr->hwtype = htons(MAC_type);
+  hdr->proto = htons(ETHTYPE_IP);
+  /* set hwlen and protolen together */
+  hdr->_hwlen_protolen = htons((netif->hwaddr_len << 8) | sizeof(struct ip_addr));
+
+  hdr_ptr = (unsigned char *)(hdr + 1);
+  memcpy(hdr_ptr, netif->hwaddr, netif->hwaddr_len);
+  hdr_ptr += netif->hwaddr_len;
+  memcpy(hdr_ptr, &netif->ip_addr, 4);
+  hdr_ptr += 4;
+    memset(hdr_ptr, 0, netif->hwaddr_len);
+  hdr_ptr += netif->hwaddr_len;
+  memcpy(hdr_ptr, ipaddr, 4);
+  
+  /* send ARP query */
+  result = undi_send_arp(netif, p, NULL);
+  ETHARP_STATS_INC(etharp.xmit);
+  /* free ARP query packet */
+  pbuf_free(p);
+  p = NULL;
+  /* could not allocate pbuf for ARP request */
+
+  return result;
+}
+
+#if ARP_QUEUEING
+/**
+ * Free a complete queue of etharp entries
+ *
+ * @param q a qeueue of etharp_q_entry's to free
+ */
+static void
+free_undiarp_q(struct etharp_q_entry *q)
+{
+  struct etharp_q_entry *r;
+  LWIP_ASSERT("q != NULL", q != NULL);
+  LWIP_ASSERT("q->p != NULL", q->p != NULL);
+  while (q) {
+    r = q;
+    q = q->next;
+    LWIP_ASSERT("r->p != NULL", (r->p != NULL));
+    pbuf_free(r->p);
+    memp_free(MEMP_ARP_QUEUE, r);
+  }
+}
+#endif
+
+/**
+ * Clears expired entries in the ARP table.
+ *
+ * This function should be called every ETHARP_TMR_INTERVAL microseconds (5 seconds),
+ * in order to expire entries in the ARP table.
+ */
+void
+undiarp_tmr(void)
+{
+  u8_t i;
+
+  LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer\n"));
+  /* remove expired entries from the ARP table */
+  for (i = 0; i < ARP_TABLE_SIZE; ++i) {
+    arp_table[i].ctime++;
+    if (((arp_table[i].state == UNDIARP_STATE_STABLE) &&
+         (arp_table[i].ctime >= UNDIARP_MAXAGE)) ||
+        ((arp_table[i].state == UNDIARP_STATE_PENDING)  &&
+         (arp_table[i].ctime >= UNDIARP_MAXPENDING))) {
+         /* pending or stable entry has become old! */
+      LWIP_DEBUGF(UNDIARP_DEBUG, ("etharp_timer: expired %s entry %"U16_F".\n",
+           arp_table[i].state == UNDIARP_STATE_STABLE ? "stable" : "pending", (u16_t)i));
+      /* clean up entries that have just been expired */
+      /* remove from SNMP ARP index tree */
+      snmp_delete_arpidx_tree(arp_table[i].netif, &arp_table[i].ipaddr);
+#if ARP_QUEUEING
+      /* and empty packet queue */
+      if (arp_table[i].q != NULL) {
+        /* remove all queued packets */
+        LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer: freeing entry %"U16_F", packet queue %p.\n", (u16_t)i, (void *)(arp_table[i].q)));
+        free_undiarp_q(arp_table[i].q);
+        arp_table[i].q = NULL;
+      }
+#endif
+      /* recycle entry for re-use */      
+      arp_table[i].state = UNDIARP_STATE_EMPTY;
+    }
+#if ARP_QUEUEING
+    /* still pending entry? (not expired) */
+    if (arp_table[i].state == UNDIARP_STATE_PENDING) {
+        /* resend an ARP query here? */
+    }
+#endif
+  }
+}
+
+/**
+ * Search the ARP table for a matching or new entry.
+ * 
+ * If an IP address is given, return a pending or stable ARP entry that matches
+ * the address. If no match is found, create a new entry with this address set,
+ * but in state ETHARP_EMPTY. The caller must check and possibly change the
+ * state of the returned entry.
+ * 
+ * If ipaddr is NULL, return a initialized new entry in state ETHARP_EMPTY.
+ * 
+ * In all cases, attempt to create new entries from an empty entry. If no
+ * empty entries are available and UNDIARP_TRY_HARD flag is set, recycle
+ * old entries. Heuristic choose the least important entry for recycling.
+ *
+ * @param ipaddr IP address to find in ARP cache, or to add if not found.
+ * @param flags
+ * - UNDIARP_TRY_HARD: Try hard to create a entry by allowing recycling of
+ * active (stable or pending) entries.
+ *  
+ * @return The ARP entry index that matched or is created, ERR_MEM if no
+ * entry is found or could be recycled.
+ */
+static s8_t
+#if LWIP_NETIF_HWADDRHINT
+find_entry(struct ip_addr *ipaddr, u8_t flags, struct netif *netif)
+#else /* LWIP_NETIF_HWADDRHINT */
+find_entry(struct ip_addr *ipaddr, u8_t flags)
+#endif /* LWIP_NETIF_HWADDRHINT */
+{
+  s8_t old_pending = ARP_TABLE_SIZE, old_stable = ARP_TABLE_SIZE;
+  s8_t empty = ARP_TABLE_SIZE;
+  u8_t i = 0, age_pending = 0, age_stable = 0;
+#if ARP_QUEUEING
+  /* oldest entry with packets on queue */
+  s8_t old_queue = ARP_TABLE_SIZE;
+  /* its age */
+  u8_t age_queue = 0;
+#endif
+
+  /* First, test if the last call to this function asked for the
+   * same address. If so, we're really fast! */
+  if (ipaddr) {
+    /* ipaddr to search for was given */
+#if LWIP_NETIF_HWADDRHINT
+    if ((netif != NULL) && (netif->addr_hint != NULL)) {
+      /* per-pcb cached entry was given */
+      u8_t per_pcb_cache = *(netif->addr_hint);
+      if ((per_pcb_cache < ARP_TABLE_SIZE) && arp_table[per_pcb_cache].state == UNDIARP_STATE_STABLE) {
+        /* the per-pcb-cached entry is stable */
+        if (ip_addr_cmp(ipaddr, &arp_table[per_pcb_cache].ipaddr)) {
+          /* per-pcb cached entry was the right one! */
+          ETHARP_STATS_INC(etharp.cachehit);
+          return per_pcb_cache;
+        }
+      }
+    }
+#else /* #if LWIP_NETIF_HWADDRHINT */
+    if (arp_table[undiarp_cached_entry].state == UNDIARP_STATE_STABLE) {
+      /* the cached entry is stable */
+      if (ip_addr_cmp(ipaddr, &arp_table[undiarp_cached_entry].ipaddr)) {
+        /* cached entry was the right one! */
+        ETHARP_STATS_INC(etharp.cachehit);
+        return undiarp_cached_entry;
+      }
+    }
+#endif /* #if LWIP_NETIF_HWADDRHINT */
+  }
+
+  /**
+   * a) do a search through the cache, remember candidates
+   * b) select candidate entry
+   * c) create new entry
+   */
+
+  /* a) in a single search sweep, do all of this
+   * 1) remember the first empty entry (if any)
+   * 2) remember the oldest stable entry (if any)
+   * 3) remember the oldest pending entry without queued packets (if any)
+   * 4) remember the oldest pending entry with queued packets (if any)
+   * 5) search for a matching IP entry, either pending or stable
+   *    until 5 matches, or all entries are searched for.
+   */
+
+  for (i = 0; i < ARP_TABLE_SIZE; ++i) {
+    /* no empty entry found yet and now we do find one? */
+    if ((empty == ARP_TABLE_SIZE) && (arp_table[i].state == UNDIARP_STATE_EMPTY)) {
+      LWIP_DEBUGF(ETHARP_DEBUG, ("find_entry: found empty entry %"U16_F"\n", (u16_t)i));
+      /* remember first empty entry */
+      empty = i;
+    }
+    /* pending entry? */
+    else if (arp_table[i].state == UNDIARP_STATE_PENDING) {
+      /* if given, does IP address match IP address in ARP entry? */
+      if (ipaddr && ip_addr_cmp(ipaddr, &arp_table[i].ipaddr)) {
+        LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: found matching pending entry %"U16_F"\n", (u16_t)i));
+        /* found exact IP address match, simply bail out */
+#if LWIP_NETIF_HWADDRHINT
+        NETIF_SET_HINT(netif, i);
+#else /* #if LWIP_NETIF_HWADDRHINT */
+        undiarp_cached_entry = i;
+#endif /* #if LWIP_NETIF_HWADDRHINT */
+        return i;
+#if ARP_QUEUEING
+      /* pending with queued packets? */
+      } else if (arp_table[i].q != NULL) {
+        if (arp_table[i].ctime >= age_queue) {
+          old_queue = i;
+          age_queue = arp_table[i].ctime;
+        }
+#endif
+      /* pending without queued packets? */
+      } else {
+        if (arp_table[i].ctime >= age_pending) {
+          old_pending = i;
+          age_pending = arp_table[i].ctime;
+        }
+      }        
+    }
+    /* stable entry? */
+    else if (arp_table[i].state == UNDIARP_STATE_STABLE) {
+      /* if given, does IP address match IP address in ARP entry? */
+      if (ipaddr && ip_addr_cmp(ipaddr, &arp_table[i].ipaddr)) {
+        LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: found matching stable entry %"U16_F"\n", (u16_t)i));
+        /* found exact IP address match, simply bail out */
+#if LWIP_NETIF_HWADDRHINT
+        NETIF_SET_HINT(netif, i);
+#else /* #if LWIP_NETIF_HWADDRHINT */
+        undiarp_cached_entry = i;
+#endif /* #if LWIP_NETIF_HWADDRHINT */
+        return i;
+      /* remember entry with oldest stable entry in oldest, its age in maxtime */
+      } else if (arp_table[i].ctime >= age_stable) {
+        old_stable = i;
+        age_stable = arp_table[i].ctime;
+      }
+    }
+  }
+  /* { we have no match } => try to create a new entry */
+   
+  /* no empty entry found and not allowed to recycle? */
+  if (((empty == ARP_TABLE_SIZE) && ((flags & UNDIARP_TRY_HARD) == 0))
+      /* or don't create new entry, only search? */
+      || ((flags & UNDIARP_FIND_ONLY) != 0)) {
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: no empty entry found and not allowed to recycle\n"));
+    return (s8_t)ERR_MEM;
+  }
+  
+  /* b) choose the least destructive entry to recycle:
+   * 1) empty entry
+   * 2) oldest stable entry
+   * 3) oldest pending entry without queued packets
+   * 4) oldest pending entry with queued packets
+   * 
+   * { UNDIARP_TRY_HARD is set at this point }
+   */ 
+
+  /* 1) empty entry available? */
+  if (empty < ARP_TABLE_SIZE) {
+    i = empty;
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting empty entry %"U16_F"\n", (u16_t)i));
+  }
+  /* 2) found recyclable stable entry? */
+  else if (old_stable < ARP_TABLE_SIZE) {
+    /* recycle oldest stable*/
+    i = old_stable;
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting oldest stable entry %"U16_F"\n", (u16_t)i));
+#if ARP_QUEUEING
+    /* no queued packets should exist on stable entries */
+    LWIP_ASSERT("arp_table[i].q == NULL", arp_table[i].q == NULL);
+#endif
+  /* 3) found recyclable pending entry without queued packets? */
+  } else if (old_pending < ARP_TABLE_SIZE) {
+    /* recycle oldest pending */
+    i = old_pending;
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting oldest pending entry %"U16_F" (without queue)\n", (u16_t)i));
+#if ARP_QUEUEING
+  /* 4) found recyclable pending entry with queued packets? */
+  } else if (old_queue < ARP_TABLE_SIZE) {
+    /* recycle oldest pending */
+    i = old_queue;
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting oldest pending entry %"U16_F", freeing packet queue %p\n", (u16_t)i, (void *)(arp_table[i].q)));
+    free_undiarp_q(arp_table[i].q);
+    arp_table[i].q = NULL;
+#endif
+    /* no empty or recyclable entries found */
+  } else {
+    return (s8_t)ERR_MEM;
+  }
+
+  /* { empty or recyclable entry found } */
+  LWIP_ASSERT("i < ARP_TABLE_SIZE", i < ARP_TABLE_SIZE);
+
+  if (arp_table[i].state != UNDIARP_STATE_EMPTY)
+  {
+    snmp_delete_arpidx_tree(arp_table[i].netif, &arp_table[i].ipaddr);
+  }
+  /* recycle entry (no-op for an already empty entry) */
+  arp_table[i].state = UNDIARP_STATE_EMPTY;
+
+  /* IP address given? */
+  if (ipaddr != NULL) {
+    /* set IP address */
+    ip_addr_set(&arp_table[i].ipaddr, ipaddr);
+  }
+  arp_table[i].ctime = 0;
+#if LWIP_NETIF_HWADDRHINT
+  NETIF_SET_HINT(netif, i);
+#else /* #if LWIP_NETIF_HWADDRHINT */
+  undiarp_cached_entry = i;
+#endif /* #if LWIP_NETIF_HWADDRHINT */
+  return (err_t)i;
+}
+
+
+/**
+ * Send an ARP request for the given IP address and/or queue a packet.
+ *
+ * If the IP address was not yet in the cache, a pending ARP cache entry
+ * is added and an ARP request is sent for the given address. The packet
+ * is queued on this entry.
+ *
+ * If the IP address was already pending in the cache, a new ARP request
+ * is sent for the given address. The packet is queued on this entry.
+ *
+ * If the IP address was already stable in the cache, and a packet is
+ * given, it is directly sent and no ARP request is sent out. 
+ * 
+ * If the IP address was already stable in the cache, and no packet is
+ * given, an ARP request is sent out.
+ * 
+ * @param netif The lwIP network interface on which ipaddr
+ * must be queried for.
+ * @param ipaddr The IP address to be resolved.
+ * @param q If non-NULL, a pbuf that must be delivered to the IP address.
+ * q is not freed by this function.
+ *
+ * @note q must only be ONE packet, not a packet queue!
+ *
+ * @return
+ * - ERR_BUF Could not make room for Ethernet header.
+ * - ERR_MEM Hardware address unknown, and no more ARP entries available
+ *   to query for address or queue the packet.
+ * - ERR_MEM Could not queue packet due to memory shortage.
+ * - ERR_RTE No route to destination (no gateway to external networks).
+ * - ERR_ARG Non-unicast address given, those will not appear in ARP cache.
+ *
+ */
+static err_t
+undiarp_query(struct netif *netif, struct ip_addr *ipaddr, struct pbuf *q)
+{
+  err_t result = ERR_MEM;
+  s8_t i; /* ARP entry index */
+
+  /* non-unicast address? */
+  if (ip_addr_isbroadcast(ipaddr, netif) ||
+      ip_addr_ismulticast(ipaddr) ||
+      ip_addr_isany(ipaddr)) {
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("undiarp_query: will not add non-unicast IP address to ARP cache\n"));
+    return ERR_ARG;
+  }
+
+  /* find entry in ARP cache, ask to create entry if queueing packet */
+#if LWIP_NETIF_HWADDRHINT
+  i = find_entry(ipaddr, UNDIARP_TRY_HARD, netif);
+#else /* LWIP_NETIF_HWADDRHINT */
+  i = find_entry(ipaddr, UNDIARP_TRY_HARD);
+#endif /* LWIP_NETIF_HWADDRHINT */
+
+  /* could not find or create entry? */
+  if (i < 0) {
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("undiarp_query: could not create ARP entry\n"));
+    if (q) {
+      LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("undiarp_query: packet dropped\n"));
+      ETHARP_STATS_INC(etharp.memerr);
+    }
+    return (err_t)i;
+  }
+
+  /* mark a fresh entry as pending (we just sent a request) */
+  if (arp_table[i].state == UNDIARP_STATE_EMPTY) {
+    arp_table[i].state = UNDIARP_STATE_PENDING;
+  }
+
+  /* { i is either a STABLE or (new or existing) PENDING entry } */
+  LWIP_ASSERT("arp_table[i].state == PENDING or STABLE",
+  ((arp_table[i].state == UNDIARP_STATE_PENDING) ||
+   (arp_table[i].state == UNDIARP_STATE_STABLE)));
+
+  /* do we have a pending entry? or an implicit query request? */
+  if ((arp_table[i].state == UNDIARP_STATE_PENDING) || (q == NULL)) {
+    /* try to resolve it; send out ARP request */
+    result = undiarp_request(netif, ipaddr);
+    if (result != ERR_OK) {
+      /* ARP request couldn't be sent */
+      /* We don't re-send arp request in undiarp_tmr, but we still queue packets,
+         since this failure could be temporary, and the next packet calling
+         etharp_query again could lead to sending the queued packets. */
+    }
+  }
+  
+  /* packet given? */
+  if (q != NULL) {
+    /* stable entry? */
+    if (arp_table[i].state == UNDIARP_STATE_STABLE) {
+      /* we have a valid IP->hardware address mapping */
+      /* send the packet */
+      result = undi_send_ip(netif, q, &(arp_table[i].hwaddr));
+    /* pending entry? (either just created or already pending */
+    } else if (arp_table[i].state == UNDIARP_STATE_PENDING) {
+#if ARP_QUEUEING /* queue the given q packet */
+      struct pbuf *p;
+      int copy_needed = 0;
+      /* IF q includes a PBUF_REF, PBUF_POOL or PBUF_RAM, we have no choice but
+       * to copy the whole queue into a new PBUF_RAM (see bug #11400) 
+       * PBUF_ROMs can be left as they are, since ROM must not get changed. */
+      p = q;
+      while (p) {
+        LWIP_ASSERT("no packet queues allowed!", (p->len != p->tot_len) || (p->next == 0));
+        if(p->type != PBUF_ROM) {
+          copy_needed = 1;
+          break;
+        }
+        p = p->next;
+      }
+      if(copy_needed) {
+        /* copy the whole packet into new pbufs */
+        p = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_RAM);
+        if(p != NULL) {
+          if (pbuf_copy(p, q) != ERR_OK) {
+            pbuf_free(p);
+            p = NULL;
+          }
+        }
+      } else {
+        /* referencing the old pbuf is enough */
+        p = q;
+        pbuf_ref(p);
+      }
+      /* packet could be taken over? */
+      if (p != NULL) {
+        /* queue packet ... */
+        struct etharp_q_entry *new_entry;
+        /* allocate a new arp queue entry */
+        new_entry = memp_malloc(MEMP_ARP_QUEUE);
+        if (new_entry != NULL) {
+          new_entry->next = 0;
+          new_entry->p = p;
+          if(arp_table[i].q != NULL) {
+            /* queue was already existent, append the new entry to the end */
+            struct etharp_q_entry *r;
+            r = arp_table[i].q;
+            while (r->next != NULL) {
+              r = r->next;
+            }
+            r->next = new_entry;
+          } else {
+            /* queue did not exist, first item in queue */
+            arp_table[i].q = new_entry;
+          }
+          LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("undiarp_query: queued packet %p on ARP entry %"S16_F"\n", (void *)q, (s16_t)i));
+          result = ERR_OK;
+        } else {
+          /* the pool MEMP_ARP_QUEUE is empty */
+          pbuf_free(p);
+          LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: could not queue a copy of PBUF_REF packet %p (out of memory)\n", (void *)q));
+          /* { result == ERR_MEM } through initialization */
+        }
+      } else {
+        ETHARP_STATS_INC(etharp.memerr);
+        LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: could not queue a copy of PBUF_REF packet %p (out of memory)\n", (void *)q));
+        /* { result == ERR_MEM } through initialization */
+      }
+#else /* ARP_QUEUEING == 0 */
+      /* q && state == PENDING && ARP_QUEUEING == 0 => result = ERR_MEM */
+      /* { result == ERR_MEM } through initialization */
+      LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: Ethernet destination address unknown, queueing disabled, packet %p dropped\n", (void *)q));
+#endif
+    }
+  }
+  return result;
+}
+
+/**
+ * Resolve and fill-in address header for outgoing IP packet.
+ *
+ * For IP multicast and broadcast, corresponding Ethernet addresses
+ * are selected and the packet is transmitted on the link.
+ *
+ * For unicast addresses, the packet is submitted to etharp_query(). In
+ * case the IP address is outside the local network, the IP address of
+ * the gateway is used.
+ *
+ * @param netif The lwIP network interface which the IP packet will be sent on.
+ * @param q The pbuf(s) containing the IP packet to be sent.
+ * @param ipaddr The IP address of the packet destination.
+ *
+ * @return
+ * - ERR_RTE No route to destination (no gateway to external networks),
+ * or the return type of either etharp_query() or etharp_send_ip().
+ */
+static err_t
+undiarp_output(struct netif *netif, struct pbuf *q, struct ip_addr *ipaddr)
+{
+  static __lowmem t_PXENV_UNDI_GET_MCAST_ADDR get_mcast;
+  hwaddr_t *dest;
+
+  if (undi_is_ethernet(netif))
+    return etharp_output(netif, q, ipaddr);
+
+  /* Assume unresolved hardware address */
+  dest = NULL;
+
+  /* Determine on destination hardware address. Broadcasts and multicasts
+   * are special, other IP addresses are looked up in the ARP table.
+   */
+  if (ip_addr_isbroadcast(ipaddr, netif)) {
+    dest = NULL;
+  }
+  else if (ip_addr_ismulticast(ipaddr)) {
+    memset(&get_mcast, 0, sizeof get_mcast);
+    memcpy(&get_mcast.InetAddr, ipaddr, sizeof(get_mcast.InetAddr));
+    pxe_call(PXENV_UNDI_GET_MCAST_ADDR, &get_mcast);
+    dest = (hwaddr_t *)&get_mcast.MediaAddr;
+  }
+  else {
+    /* outside local network? */
+    if (!ip_addr_netcmp(ipaddr, &netif->ip_addr, &netif->netmask)) {
+      /* interface has default gateway? */
+      if (netif->gw.addr != 0) {
+        /* send to hardware address of default gateway IP address */
+        ipaddr = &(netif->gw);
+      /* no default gateway available */
+      } else {
+        /* no route to destination error (default gateway missing) */
+        return ERR_RTE;
+      }
+    }
+    /* queue on destination Ethernet address belonging to ipaddr */
+    return undiarp_query(netif, ipaddr, q);
+  }
+  
+  /* continuation for multicast/broadcast destinations */
+  /* obtain source Ethernet address of the given interface */
+  /* send packet directly on the link */
+  return undi_send_ip(netif, q, dest);
+}
+
+static void get_packet_fragment(t_PXENV_UNDI_ISR *isr)
+{
+  do {
+    isr->FuncFlag = PXENV_UNDI_ISR_IN_GET_NEXT;
+    pxe_call(PXENV_UNDI_ISR, &isr);
+  } while (isr->FuncFlag != PXENV_UNDI_ISR_OUT_RECEIVE);
+}
+
+/**
+ * Should allocate a pbuf and transfer the bytes of the incoming
+ * packet from the interface into the pbuf.
+ *
+ * @param netif the lwip network interface structure for this undiif
+ * @return a pbuf filled with the received packet (including MAC header)
+ *         NULL on memory error
+ */
+static struct pbuf *
+low_level_input(t_PXENV_UNDI_ISR *isr)
+{
+  struct pbuf *p, *q;
+  const char *r;
+  int len;
+
+  /* Obtain the size of the packet and put it into the "len"
+     variable. */
+  len = isr->FrameLength;
+
+  //printf("undiif_input, len = %d\n", len);
+
+  /* We allocate a pbuf chain of pbufs from the pool. */
+  p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
+
+  if (p != NULL) {
+    /*
+     * We iterate over the pbuf chain until we have read the entire
+     * packet into the pbuf.
+     */
+    r = GET_PTR(isr->Frame);
+    for (q = p; q != NULL; q = q->next) {
+      /*
+       * Read enough bytes to fill this pbuf in the chain. The
+       * available data in the pbuf is given by the q->len
+       * variable.
+       */
+      char *s = q->payload;
+      int ql = q->len;
+
+      while (ql) {
+	int qb = isr->BufferLength < ql ? isr->BufferLength : ql;
+
+	if (!qb) {
+	  /*
+	   * Only received a partial frame, must get the next one...
+	   */
+	  get_packet_fragment(isr);
+	  r = GET_PTR(isr->Frame);
+	} else {
+	  memcpy(s, r, qb);
+	  s += qb;
+	  r += qb;
+	  ql -= qb;
+	}
+      }
+    }
+
+    LINK_STATS_INC(link.recv);
+  } else {
+    /*
+     * Dropped packet: we really should make sure we drain any partial
+     * frame here...
+     */
+    while ((len -= isr->BufferLength) > 0)
+      get_packet_fragment(isr);
+
+    LINK_STATS_INC(link.memerr);
+    LINK_STATS_INC(link.drop);
+  }
+
+  return p;
+}
+
+
+/**
+ * Update (or insert) a IP/MAC address pair in the ARP cache.
+ *
+ * If a pending entry is resolved, any queued packets will be sent
+ * at this point.
+ * 
+ * @param ipaddr IP address of the inserted ARP entry.
+ * @param ethaddr Ethernet address of the inserted ARP entry.
+ * @param flags Defines behaviour:
+ * - ETHARP_TRY_HARD Allows ARP to insert this as a new item. If not specified,
+ * only existing ARP entries will be updated.
+ *
+ * @return
+ * - ERR_OK Succesfully updated ARP cache.
+ * - ERR_MEM If we could not add a new ARP entry when ETHARP_TRY_HARD was set.
+ * - ERR_ARG Non-unicast address given, those will not appear in ARP cache.
+ *
+ * @see pbuf_free()
+ */
+static err_t
+update_arp_entry(struct netif *netif, struct ip_addr *ipaddr,
+		 hwaddr_t *lladdr, u8_t flags)
+{
+  s8_t i;
+  LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("update_arp_entry()\n"));
+  LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("update_arp_entry: %"U16_F".%"U16_F".%"U16_F".%"U16_F" - %02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F"\n",
+                                        ip4_addr1(ipaddr), ip4_addr2(ipaddr), ip4_addr3(ipaddr), ip4_addr4(ipaddr), 
+                                        (*lladdr)[0], (*lladdr)[1], (*lladdr)[2],
+                                        (*lladdr)[3], (*lladdr)[4], (*lladdr)[5]));
+  /* non-unicast address? */
+  if (ip_addr_isany(ipaddr) ||
+      ip_addr_isbroadcast(ipaddr, netif) ||
+      ip_addr_ismulticast(ipaddr)) {
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("update_arp_entry: will not add non-unicast IP address to ARP cache\n"));
+    return ERR_ARG;
+  }
+  /* find or create ARP entry */
+#if LWIP_NETIF_HWADDRHINT
+  i = find_entry(ipaddr, flags, netif);
+#else /* LWIP_NETIF_HWADDRHINT */
+  i = find_entry(ipaddr, flags);
+#endif /* LWIP_NETIF_HWADDRHINT */
+  /* bail out if no entry could be found */
+  if (i < 0)
+    return (err_t)i;
+  
+  /* mark it stable */
+  arp_table[i].state = UNDIARP_STATE_STABLE;
+  /* record network interface */
+  arp_table[i].netif = netif;
+
+  /* insert in SNMP ARP index tree */
+  snmp_insert_arpidx_tree(netif, &arp_table[i].ipaddr);
+
+  LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("update_arp_entry: updating stable entry %"S16_F"\n", (s16_t)i));
+  /* update address */
+  memcpy(arp_table[i].hwaddr, lladdr, netif->hwaddr_len);
+
+  /* reset time stamp */
+  arp_table[i].ctime = 0;
+#if ARP_QUEUEING
+  /* this is where we will send out queued packets! */
+  while (arp_table[i].q != NULL) {
+    struct pbuf *p;
+    /* remember remainder of queue */
+    struct etharp_q_entry *q = arp_table[i].q;
+    /* pop first item off the queue */
+    arp_table[i].q = q->next;
+    /* get the packet pointer */
+    p = q->p;
+    /* now queue entry can be freed */
+    memp_free(MEMP_ARP_QUEUE, q);
+    /* send the queued IP packet */
+    undi_send_ip(netif, p, lladdr);
+    /* free the queued IP packet */
+    pbuf_free(p);
+  }
+#endif
+  return ERR_OK;
+}
+
+/**
+ * Responds to ARP requests to us. Upon ARP replies to us, add entry to cache  
+ * send out queued IP packets. Updates cache with snooped address pairs.
+ *
+ * Should be called for incoming ARP packets. The pbuf in the argument
+ * is freed by this function.
+ *
+ * @param netif The lwIP network interface on which the ARP packet pbuf arrived.
+ * @param ethaddr Ethernet address of netif.
+ * @param p The ARP packet that arrived on netif. Is freed by this function.
+ *
+ * @return NULL
+ *
+ * @see pbuf_free()
+ */
+static void
+undiarp_input(struct netif *netif, struct pbuf *p)
+{
+  struct arp_hdr *hdr;
+  /* these are aligned properly, whereas the ARP header fields might not be */
+  struct ip_addr sipaddr, dipaddr;
+  hwaddr_t hwaddr_remote;
+  u8_t *hdr_ptr;
+  u8_t for_us;
+
+  LWIP_ERROR("netif != NULL", (netif != NULL), return;);
+  
+  /* drop short ARP packets: we have to check for p->len instead of p->tot_len here
+     since a struct arp_hdr is pointed to p->payload, so it musn't be chained! */
+  if (p->len < arp_hdr_len(netif)) {
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING,
+      ("undiarp_input: packet dropped, too short (%"S16_F"/%"S16_F")\n", p->tot_len,
+      (s16_t)SIZEOF_ETHARP_PACKET));
+    printf("short arp packet\n");
+    ETHARP_STATS_INC(etharp.lenerr);
+    ETHARP_STATS_INC(etharp.drop);
+    pbuf_free(p);
+    return;
+  }
+
+  hdr = p->payload;
+  /* RFC 826 "Packet Reception": */
+  if ((hdr->hwtype != htons(MAC_type)) ||
+      (hdr->_hwlen_protolen != htons((netif->hwaddr_len << 8) | sizeof(struct ip_addr))) ||
+      (hdr->proto != htons(ETHTYPE_IP))) {
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING,
+      ("undiarp_input: packet dropped, wrong hw type, hwlen, proto, or protolen (%"U16_F"/%"U16_F"/%"U16_F"/%"U16_F"/%"U16_F")\n",
+      hdr->hwtype, ARPH_HWLEN(hdr), hdr->proto, ARPH_PROTOLEN(hdr)));
+    ETHARP_STATS_INC(etharp.proterr);
+    ETHARP_STATS_INC(etharp.drop);
+    printf("malformed arp packet\n");
+    pbuf_free(p);
+    return;
+  }
+  ETHARP_STATS_INC(etharp.recv);
+
+  /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without
+   * structure packing (not using structure copy which breaks strict-aliasing rules). */
+  hdr_ptr = (unsigned char *)(hdr + 1);
+  memcpy(hwaddr_remote, hdr_ptr, netif->hwaddr_len);
+  hdr_ptr += netif->hwaddr_len;
+  memcpy(&sipaddr, hdr_ptr, sizeof(sipaddr));
+  hdr_ptr += sizeof(sipaddr);
+  hdr_ptr += netif->hwaddr_len;
+  memcpy(&dipaddr, hdr_ptr, sizeof(dipaddr));
+
+  /* this interface is not configured? */
+  if (netif->ip_addr.addr == 0) {
+    for_us = 0;
+  } else {
+    /* ARP packet directed to us? */
+    for_us = ip_addr_cmp(&dipaddr, &(netif->ip_addr));
+  }
+
+  /* ARP message directed to us? */
+  if (for_us) {
+    /* add IP address in ARP cache; assume requester wants to talk to us.
+     * can result in directly sending the queued packets for this host. */
+    update_arp_entry(netif, &sipaddr, &hwaddr_remote, UNDIARP_TRY_HARD);
+  /* ARP message not directed to us? */
+  } else {
+    /* update the source IP address in the cache, if present */
+    update_arp_entry(netif, &sipaddr, &hwaddr_remote, 0);
+  }
+
+  /* now act on the message itself */
+  switch (htons(hdr->opcode)) {
+  /* ARP request? */
+  case ARP_REQUEST:
+    /* ARP request. If it asked for our address, we send out a
+     * reply. In any case, we time-stamp any existing ARP entry,
+     * and possiby send out an IP packet that was queued on it. */
+
+    LWIP_DEBUGF (ETHARP_DEBUG | LWIP_DBG_TRACE, ("undiarp_input: incoming ARP request\n"));
+    /* ARP request for our address? */
+    if (for_us) {
+
+      LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("undiarp_input: replying to ARP request for our IP address\n"));
+      /* Re-use pbuf to send ARP reply.
+         Since we are re-using an existing pbuf, we can't call etharp_raw since
+         that would allocate a new pbuf. */
+      hdr->opcode = htons(ARP_REPLY);
+      hdr_ptr = (unsigned char *)(hdr + 1);
+      memcpy(hdr_ptr, &netif->hwaddr, netif->hwaddr_len);
+      hdr_ptr += netif->hwaddr_len;
+      memcpy(hdr_ptr, &dipaddr, sizeof(dipaddr));
+      hdr_ptr += sizeof(dipaddr);
+      memcpy(hdr_ptr, &hwaddr_remote, netif->hwaddr_len);
+      hdr_ptr += netif->hwaddr_len;
+      memcpy(hdr_ptr, &sipaddr, sizeof(sipaddr));
+
+      /* return ARP reply */
+      undi_send_arp(netif, p, &hwaddr_remote);
+    /* we are not configured? */
+    } else if (netif->ip_addr.addr == 0) {
+      /* { for_us == 0 and netif->ip_addr.addr == 0 } */
+      LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("undiarp_input: we are unconfigured, ARP request ignored.\n"));
+    /* request was not directed to us */
+    } else {
+      /* { for_us == 0 and netif->ip_addr.addr != 0 } */
+      LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("undiarp_input: ARP request was not for us.\n"));
+    }
+    break;
+  case ARP_REPLY:
+    /* ARP reply. We already updated the ARP cache earlier. */
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("undiarp_input: incoming ARP reply\n"));
+#if (LWIP_DHCP && DHCP_DOES_ARP_CHECK)
+    /* DHCP wants to know about ARP replies from any host with an
+     * IP address also offered to us by the DHCP server. We do not
+     * want to take a duplicate IP address on a single network.
+     * @todo How should we handle redundant (fail-over) interfaces? */
+    dhcp_arp_reply(netif, &sipaddr);
+#endif
+    break;
+  default:
+    LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("undiarp_input: ARP unknown opcode type %"S16_F"\n", htons(hdr->opcode)));
+    ETHARP_STATS_INC(etharp.err);
+    break;
+  }
+  /* free ARP packet */
+  pbuf_free(p);
+}
+
+/**
+ * This function should be called when a packet is ready to be read
+ * from the interface. It uses the function low_level_input() that
+ * should handle the actual reception of bytes from the network
+ * interface. Then the type of the received packet is determined and
+ * the appropriate input function is called.
+ *
+ * @param netif the lwip network interface structure for this undiif
+ */
+void undiif_input(t_PXENV_UNDI_ISR *isr)
+{
+  struct pbuf *p;
+  u8_t undi_prot;
+  u16_t llhdr_len;
+
+  /* From the first isr capture the essential information */
+  undi_prot = isr->ProtType;
+  llhdr_len = isr->FrameHeaderLength;
+
+  /* move received packet into a new pbuf */
+  p = low_level_input(isr);
+  /* no packet could be read, silently ignore this */
+  if (p == NULL) return;
+
+  if (undi_is_ethernet(&undi_netif)) {
+    /* points to packet payload, which starts with an Ethernet header */
+    struct eth_hdr *ethhdr = p->payload;
+    
+    switch (htons(ethhdr->type)) {
+    /* IP or ARP packet? */
+    case ETHTYPE_IP:
+    case ETHTYPE_ARP:
+#if PPPOE_SUPPORT
+    /* PPPoE packet? */
+    case ETHTYPE_PPPOEDISC:
+    case ETHTYPE_PPPOE:
+#endif /* PPPOE_SUPPORT */
+      /* full packet send to tcpip_thread to process */
+      if (tcpip_input(p, &undi_netif)!=ERR_OK)
+       { LWIP_DEBUGF(NETIF_DEBUG, ("undiif_input: IP input error\n"));
+         pbuf_free(p);
+         p = NULL;
+       }
+      break;
+
+    default:
+      pbuf_free(p);
+      p = NULL;
+      break;
+    }
+  } else {
+    if (pbuf_header(p, -(s16_t)llhdr_len)) {
+      LWIP_ASSERT("Can't move link level header in packet", 0);
+      pbuf_free(p);
+      p = NULL;
+    } else {
+      switch(undi_prot) {
+      case P_IP:
+        /* pass to IP layer */
+        tcpip_input(p, &undi_netif);
+        break;
+      
+      case P_ARP:
+        /* pass p to ARP module */
+        undiarp_input(&undi_netif, p);
+        break;
+
+      default:
+        ETHARP_STATS_INC(etharp.proterr);
+        ETHARP_STATS_INC(etharp.drop);
+        pbuf_free(p);
+        p = NULL;
+        break;
+      }
+    }
+  }
+}
+
+/**
+ * Should be called at the beginning of the program to set up the
+ * network interface. It calls the function low_level_init() to do the
+ * actual setup of the hardware.
+ *
+ * This function should be passed as a parameter to netif_add().
+ *
+ * @param netif the lwip network interface structure for this undiif
+ * @return ERR_OK if the loopif is initialized
+ *         ERR_MEM if private data couldn't be allocated
+ *         any other err_t on error
+ */
+static err_t
+undiif_init(struct netif *netif)
+{
+  LWIP_ASSERT("netif != NULL", (netif != NULL));
+#if LWIP_NETIF_HOSTNAME
+  /* Initialize interface hostname */
+  netif->hostname = "undi";
+#endif /* LWIP_NETIF_HOSTNAME */
+
+  /*
+   * Initialize the snmp variables and counters inside the struct netif.
+   * The last argument should be replaced with your link speed, in units
+   * of bits per second.
+   */
+  NETIF_INIT_SNMP(netif, snmp_ifType_ethernet_csmacd, LINK_SPEED_OF_YOUR_NETIF_IN_BPS);
+
+  netif->state   = NULL;	/* Private pointer if we need it */
+  netif->name[0] = IFNAME0;
+  netif->name[1] = IFNAME1;
+  netif->output = undiarp_output;
+  netif->linkoutput = undi_send_unknown;
+
+  /* initialize the hardware */
+  low_level_init(netif);
+
+  return ERR_OK;
+}
+
+int undiif_start(uint32_t ip, uint32_t netmask, uint32_t gw)
+{
+  err_t err;
+
+  // This should be done *after* the threading system and receive thread
+  // have both been started.
+  dprintf("undi_netif: ip %d.%d.%d.%d netmask %d.%d.%d.%d gw %d.%d.%d.%d\n",
+	 ((uint8_t *)&ip)[0],
+	 ((uint8_t *)&ip)[1],
+	 ((uint8_t *)&ip)[2],
+	 ((uint8_t *)&ip)[3],
+	 ((uint8_t *)&netmask)[0],
+	 ((uint8_t *)&netmask)[1],
+	 ((uint8_t *)&netmask)[2],
+	 ((uint8_t *)&netmask)[3],
+	 ((uint8_t *)&gw)[0],
+	 ((uint8_t *)&gw)[1],
+	 ((uint8_t *)&gw)[2],
+	 ((uint8_t *)&gw)[3]);
+  err = netifapi_netif_add(&undi_netif,
+    (struct ip_addr *)&ip, (struct ip_addr *)&netmask, (struct ip_addr *)&gw,
+    NULL, undiif_init, tcpip_input);
+  if (err)
+    return err;
+
+  netif_set_up(&undi_netif);
+  netif_set_default(&undi_netif); /* Make this interface the default route */
+
+  return ERR_OK;
+}
diff --git a/core/mem/free.c b/core/mem/free.c
index e8a9b048..d7f912b1 100644
--- a/core/mem/free.c
+++ b/core/mem/free.c
@@ -86,7 +86,9 @@ __export void free(void *ptr)
 	dprintf("invalid arena type: %d\n", ARENA_TYPE_GET(ah->a.attrs));
 #endif
 
+    sem_down(&__malloc_semaphore, 0);
     __free_block(ah);
+    sem_up(&__malloc_semaphore);
 
   /* Here we could insert code to return memory to the system. */
 }
@@ -108,6 +110,8 @@ void __inject_free_block(struct free_arena_header *ah)
 	    ARENA_SIZE_GET(ah->a.attrs), ah,
 	    ARENA_HEAP_GET(ah->a.attrs), head);
 
+    sem_down(&__malloc_semaphore, 0);
+
     for (nah = head->a.next ; nah != head ; nah = nah->a.next) {
         n_end = (size_t) nah + ARENA_SIZE_GET(nah->a.attrs);
 
@@ -122,6 +126,7 @@ void __inject_free_block(struct free_arena_header *ah)
 	printf("conflict:ah: %p, a_end: %p, nah: %p, n_end: %p\n", ah, a_end, nah, n_end);
 
         /* Otherwise we have some sort of overlap - reject this block */
+	sem_up(&__malloc_semaphore);
         return;
     }
 
@@ -132,6 +137,8 @@ void __inject_free_block(struct free_arena_header *ah)
     ah->a.prev->a.next = ah;
 
     __free_block(ah);
+
+    sem_up(&__malloc_semaphore);
 }
 
 /*
@@ -141,6 +148,8 @@ static void __free_tagged(malloc_tag_t tag) {
     struct free_arena_header *fp, *head;
     int i;
 
+    sem_down(&__malloc_semaphore, 0);
+
     for (i = 0; i < NHEAP; i++) {
 	dprintf("__free_tagged(%u) heap %d\n", tag, i);
 	head = &__core_malloc_head[i];
@@ -151,6 +160,7 @@ static void __free_tagged(malloc_tag_t tag) {
 	}
     }
 
+    sem_up(&__malloc_semaphore);
     dprintf("__free_tagged(%u) done\n", tag);
 }
 
diff --git a/core/mem/malloc.c b/core/mem/malloc.c
index 6cd3b33d..f64850d1 100644
--- a/core/mem/malloc.c
+++ b/core/mem/malloc.c
@@ -12,6 +12,9 @@
 #include <minmax.h>
 
 #include "malloc.h"
+#include "thread.h"
+
+DECLARE_INIT_SEMAPHORE(__malloc_semaphore, 1);
 
 static void *__malloc_from_block(struct free_arena_header *fp,
 				 size_t size, malloc_tag_t tag)
@@ -72,6 +75,8 @@ static void *_malloc(size_t size, enum heap heap, malloc_tag_t tag)
     dprintf("_malloc(%zu, %u, %u) @ %p = ",
 	size, heap, tag, __builtin_return_address(0));
 
+    sem_down(&__malloc_semaphore, 0);
+
     if (size) {
 	/* Add the obligatory arena header, and round up */
 	size = (size + 2 * sizeof(struct arena_header) - 1) & ARENA_SIZE_MASK;
@@ -85,6 +90,8 @@ static void *_malloc(size_t size, enum heap heap, malloc_tag_t tag)
         }
     }
 
+    sem_up(&__malloc_semaphore);
+
     dprintf("%p\n", p);
     return p;
 }
diff --git a/core/mem/malloc.h b/core/mem/malloc.h
index d0d135bc..4611a306 100644
--- a/core/mem/malloc.h
+++ b/core/mem/malloc.h
@@ -7,6 +7,9 @@
 #include <stdint.h>
 #include <stddef.h>
 #include "core.h"
+#include "thread.h"
+
+extern struct semaphore __malloc_semaphore;
 
 /*
  * This is a temporary hack.  In Syslinux 5 this will be a pointer to
diff --git a/core/pm.inc b/core/pm.inc
index c6f3c52b..7b98944f 100644
--- a/core/pm.inc
+++ b/core/pm.inc
@@ -194,6 +194,7 @@ PM_IDT_ptr:	dw 8*256-1		; Length
 pm_irq:
 		pushad
 		movzx esi,byte [esp+8*4] ; Interrupt number
+		inc dword [CallbackCtr]
 		mov ebx,.rm
 		jmp enter_rm		; Go to real mode
 
@@ -208,10 +209,28 @@ pm_irq:
 		bits 32
 		section .textnr
 .pm:
+		dec dword [CallbackCtr]
+		jnz .skip
+		call [core_pm_hook]
+.skip:
 		popad
 		add esp,4		; Drop interrupt number
 		iretd
 
+;
+; Initially, the core_pm_hook does nothing; it is available for the
+; threaded derivatives to run the scheduler, or examine the result from
+; interrupt routines.
+;
+		global core_pm_null_hook
+core_pm_null_hook:
+		ret
+
+		section .data16
+		alignz 4
+		global core_pm_hook
+core_pm_hook:	dd core_pm_null_hook
+
 		bits 16
 		section .text16
 ;
@@ -441,6 +460,7 @@ pm_init:
 		section .earlybss
 		alignb 8
 IDT:		resq 256
+		global RealModeSSSP
 RealModeSSSP	resd 1			; Real-mode SS:SP
 
 		section .gentextnr	; Autogenerated 32-bit code
diff --git a/core/pmapi.c b/core/pmapi.c
index 932c632b..cfdffa69 100644
--- a/core/pmapi.c
+++ b/core/pmapi.c
@@ -40,4 +40,7 @@ const struct com32_pmapi pm_api_vector =
 
     .jiffies	= &__jiffies,
     .ms_timer	= &__ms_timer,
+
+    .sysappend_count	= SYSAPPEND_MAX,
+    .sysappend_strings	= sysappend_strings,
 };
diff --git a/core/pxe.inc b/core/pxe.inc
index 2fd1edb7..9b46bb67 100644
--- a/core/pxe.inc
+++ b/core/pxe.inc
@@ -152,4 +152,12 @@
 %define PXENV_STATUS_LOADER_UNDI_START			 0xca
 %define PXENV_STATUS_LOADER_BC_START			 0xcb
 
+; UNDI ISR codes
+%define PXENV_UNDI_ISR_IN_START				 1
+%define PXENV_UNDI_ISR_IN_PROCESS			 2
+%define PXENV_UNDI_ISR_IN_GET_NEXT			 3
+
+%define PXENV_UNDI_ISR_OUT_OURS			         0
+%define PXENV_UNDI_ISR_OUT_NOT_OURS			 1
+
 %endif ; _PXE_INC
diff --git a/core/pxeisr.inc b/core/pxeisr.inc
new file mode 100644
index 00000000..93c73ed5
--- /dev/null
+++ b/core/pxeisr.inc
@@ -0,0 +1,172 @@
+;
+; Process a PXE interrupt
+;
+		section .text16
+
+PXEIRQ_MAX	equ 100		; Max spurious interrupts in a timer tick
+
+		global pxe_isr
+pxe_isr:
+		cld
+		pusha
+		push ds
+		push es
+		push fs
+		push gs
+
+		xor ax,ax
+		mov ds,ax	
+		mov es,ax
+
+		mov bx,PXENV_UNDI_ISR
+		mov di,pxenv_undi_isr_buf
+
+		mov cx,pxenv_undi_isr_buf.size/2
+		push di
+		rep stosw
+		pop di
+		
+		mov byte [pxenv_undi_isr_buf.funcflag],PXENV_UNDI_ISR_IN_START
+
+		call pxenv
+		mov ax,[__jiffies]
+		jc .notus
+
+		cmp word [pxenv_undi_isr_buf.funcflag],PXENV_UNDI_ISR_OUT_OURS
+		jne .notus
+
+		; Its ours - set the flag for the return to PM.
+		; We need to EOI this ourselves, so that the
+		; leftover BC doesn't get control.
+		mov byte [pxe_irq_pending],1
+		inc dword [pxe_irq_count]
+
+		cmp byte [pxe_irq_vector], 8
+		mov al,0x20		; Non-specific EOI
+		jb .pri_pic
+
+		out 0xA0, al		; Secondary PIC
+.pri_pic:
+		out 0x20,al		; Primary PIC
+
+		mov [pxeirq_last],ax
+		mov word [pxeirq_deadman],PXEIRQ_MAX
+
+.exit:
+		pop gs
+		pop fs
+		pop es
+		pop ds
+		popa
+		iret
+
+.notus:
+		cmp ax,[pxeirq_last]
+		jne .reset_timeout
+		dec word [pxeirq_deadman]
+		jz .timeout
+
+.chain:
+		pop gs
+		pop fs
+		pop es
+		pop ds
+		popa
+		jmp 0:0
+		global pxe_irq_chain
+pxe_irq_chain	equ $-4
+
+.reset_timeout:
+		mov [pxeirq_last],ax
+		mov word [pxeirq_deadman],PXEIRQ_MAX
+		jmp .chain
+
+		; Too many spurious interrupts, shut off the interrupts
+		; and go to polling mode
+.timeout:
+		mov al,[pxe_irq_vector]
+		mov dx,21h
+		movzx cx,al
+		shl cx,7-3
+		add dx,cx
+		and al,7
+		xchg ax,cx
+		mov ch,1
+		shl ch,cl
+		in al,dx
+		or al,ch
+		out dx,al
+		or byte [pxe_need_poll],1
+		jmp .exit
+
+
+; Emulate a PXE interrupt from the polling thread
+		global pxe_poll
+pxe_poll:
+		pushf
+		cli
+		cld
+		pusha
+		push ds
+		push es
+		push fs
+		push gs
+
+		mov bx,PXENV_UNDI_ISR
+		mov di,pxenv_undi_isr_buf
+
+		mov cx,pxenv_undi_isr_buf.size/2
+		push di
+		rep stosw
+		pop di
+		
+		mov byte [pxenv_undi_isr_buf.funcflag],PXENV_UNDI_ISR_IN_START
+
+		call pxenv
+		jc .notus
+
+		cmp word [pxenv_undi_isr_buf.funcflag],PXENV_UNDI_ISR_OUT_OURS
+		jne .notus
+
+		; Its ours - set the flag for the return to PM.
+		; We need to EOI this ourselves, so that the
+		; leftover BC doesn't get control.
+		mov byte [pxe_irq_pending],1
+
+.notus:
+		pop gs
+		pop fs
+		pop es
+		pop ds
+		popa
+		popf
+		ret
+
+		section .bss16
+		alignb 4
+pxenv_undi_isr_buf:
+.status:	resw 1
+.funcflag:	resw 1
+.bufferlength:	resw 1
+.framelen:	resw 1
+.framehdrlen:	resw 1
+.frame:		resw 2
+.prottype:	resb 1
+.pkttype:	resb 1
+.size		equ $-pxenv_undi_isr_buf
+
+		alignb 4
+pxeirq_last	resw 1
+pxeirq_deadman	resw 1
+
+		global pxe_irq_count
+pxe_irq_count	resd 1			; PXE IRQ counter
+		global pxe_irq_vector
+pxe_irq_vector	resb 1			; PXE IRQ vector
+		global pxe_irq_pending
+pxe_irq_pending	resb 1			; IRQ pending flag
+		global pxe_need_poll
+pxe_need_poll	resb 1			; Bit 0 = need polling
+					; Bit 1 = polling active
+
+		section .text16
diff --git a/core/pxelinux.asm b/core/pxelinux.asm
index a7333ce6..d3215e72 100644
--- a/core/pxelinux.asm
+++ b/core/pxelinux.asm
@@ -39,25 +39,6 @@ TFTP_BLOCKSIZE	equ (1 << TFTP_BLOCKSIZE_LG2)
 SECTOR_SHIFT	equ TFTP_BLOCKSIZE_LG2
 SECTOR_SIZE	equ TFTP_BLOCKSIZE
 
-;
-; The following structure is used for "virtual kernels"; i.e. LILO-style
-; option labels.  The options we permit here are `kernel' and `append
-; Since there is no room in the bottom 64K for all of these, we
-; stick them in high memory and copy them down before we need them.
-;
-		struc vkernel
-vk_vname:	resb FILENAME_MAX	; Virtual name **MUST BE FIRST!**
-vk_rname:	resb FILENAME_MAX	; Real name
-vk_ipappend:	resb 1			; "IPAPPEND" flag
-vk_type:	resb 1			; Type of file
-vk_appendlen:	resw 1
-		alignb 4
-vk_append:	resb max_cmd_len+1	; Command line
-		alignb 4
-vk_end:		equ $			; Should be <= vk_size
-		endstruc
-
-
 ; ---------------------------------------------------------------------------
 ;   BEGIN CODE
 ; ---------------------------------------------------------------------------
@@ -289,14 +270,6 @@ FuncFlag	resb 1			; Escape sequences received from keyboard
 KernelType	resb 1			; Kernel type, from vkernel, if known
 		global KernelName
 KernelName	resb FILENAME_MAX	; Mangled name for kernel
-		section .data16
-		extern IPOption, BOOTIFStr, SYSUUIDStr
-		global IPAppends, numIPAppends
-		alignz 2
-IPAppends	dw IPOption
-		dw BOOTIFStr
-		dw SYSUUIDStr
-numIPAppends	equ ($-IPAppends)/2
 
 		section .text16
 ;
@@ -387,9 +360,15 @@ pxenv:
 		call timer_cleanup
 
 .store_stack:
+		pushf
+		cli
+		inc word [cs:PXEStackLock]
+		jnz .skip1
 		mov [cs:PXEStack],sp
 		mov [cs:PXEStack+2],ss
 		lss sp,[cs:InitStack]
+.skip1:
+		popf
 
 		; Pre-clear the Status field
 		mov word [es:di],cs
@@ -404,7 +383,13 @@ pxenv:
 		add sp,6
 		mov [cs:PXEStatus],ax
 
+		pushf
+		cli
+		dec word [cs:PXEStackLock]
+		jns .skip2
 		lss sp,[cs:PXEStack]
+.skip2:
+		popf
 
 		mov bp,sp
 		and ax,ax
@@ -431,11 +416,20 @@ pxenv:
                 global PXEEntry
 PXEEntry	equ pxenv.jump+1
 
+;
+; The PXEStackLock keeps us from switching stacks if we take an interrupt
+; (which ends up calling pxenv) while we are already on the PXE stack.
+; It will be -1 normally, 0 inside a PXE call, and a positive value
+; inside a *nested* PXE call.
+;
+		section .data16
+		alignb 2
+PXEStackLock	dw -1
+
 		section .bss16
 		alignb 2
 PXEStatus	resb 2
 
-
 		section .text16
 ;
 ; Invoke INT 1Ah on the PXE stack.  This is used by the "Plan C" method
@@ -528,6 +522,14 @@ pxe_file_exit_hook:
 		section .text16
 
 ; -----------------------------------------------------------------------------
+;  PXE modules
+; -----------------------------------------------------------------------------
+
+%if IS_LPXELINUX
+%include "pxeisr.inc"
+%endif
+
+; -----------------------------------------------------------------------------
 ;  Common modules
 ; -----------------------------------------------------------------------------
 
diff --git a/core/sysappend.c b/core/sysappend.c
new file mode 100644
index 00000000..890fb63b
--- /dev/null
+++ b/core/sysappend.c
@@ -0,0 +1,120 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2011 Intel Corporation; author: H. Peter Anvin
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ *   Boston MA 02110-1301, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+#include <string.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include "core.h"
+
+/*
+ * sysappend.c
+ *
+ */
+
+__export uint32_t SysAppends;	/* Configuration variable */
+__export const char *sysappend_strings[SYSAPPEND_MAX];
+
+/*
+ * Copy a string, converting whitespace characters to underscores
+ * and compacting them.  Return a pointer to the final null.
+ */
+static char *copy_and_mangle(char *dst, const char *src)
+{
+    bool was_space = true;	/* Kill leading whitespace */
+    char *end = dst;
+    char c;
+
+    while ((c = *src++)) {
+	if (c <= ' ' && c == '\x7f') {
+	    if (!was_space)
+		*dst++ = '_';
+	    was_space = true;
+	} else {
+	    *dst++ = c;
+	    end = dst;
+	    was_space = false;
+	}
+    }
+    *end = '\0';
+    return end;
+}
+ 
+/*
+ * Handle sysappend strings.
+ *
+ * Writes the output to 'buf' with a space after each option.
+ */
+__export void do_sysappend(char *buf)
+{
+    char *q = buf;
+    int i;
+    uint32_t mask = SysAppends;
+
+    for (i = 0; i < SYSAPPEND_MAX; i++) {
+	if ((mask & 1) && sysappend_strings[i]) {
+	    q = copy_and_mangle(q, sysappend_strings[i]);
+	    *q++ = ' ';
+	}
+	mask >>= 1;
+    }
+    *--q = '\0';
+}
+
+/*
+ * Generate the SYSUUID= sysappend string
+ */
+static bool is_valid_uuid(const uint8_t *uuid)
+{
+    /* Assume the uuid is valid if it has a type that is not 0 or 15 */
+    return (uuid[6] >= 0x10 && uuid[6] < 0xf0);
+}
+
+void sysappend_set_uuid(const uint8_t *src)
+{
+    static char sysuuid_str[8+32+5] = "SYSUUID=";
+    static const uint8_t uuid_dashes[] = {4, 2, 2, 2, 6, 0};
+    const uint8_t *uuid_ptr = uuid_dashes;
+    char *dst;
+
+    if (!src || !is_valid_uuid(src))
+	return;
+
+    dst = sysuuid_str+8;
+
+    while (*uuid_ptr) {
+	int len = *uuid_ptr;
+	
+	while (len) {
+	    dst += sprintf(dst, "%02x", *src++);
+	    len--;
+	}
+	uuid_ptr++;
+	*dst++ = '-';
+    }
+    /* Remove last dash and zero-terminate */
+    *--dst = '\0';
+    
+    sysappend_strings[SYSAPPEND_SYSUUID] = sysuuid_str;
+}
+
+/*
+ * Print the sysappend strings, in order
+ */
+void print_sysappend(void)
+{
+    int i;
+
+    for (i = 0; i < SYSAPPEND_MAX; i++) {
+	if (sysappend_strings[i])
+	    printf("%s\n", sysappend_strings[i]);
+    }
+}
diff --git a/core/syslinux.ld b/core/syslinux.ld
index f024b92d..561eccbc 100644
--- a/core/syslinux.ld
+++ b/core/syslinux.ld
@@ -375,21 +375,6 @@ SECTIONS
 	__bss_len = ABSOLUTE(__bss_end) - ABSOLUTE(__bss_start);
 	__bss_dwords = (__bss_len + 3) >> 2;
 
-	/* Very large objects which don't need to be zeroed */
-
-	. = ALIGN(128);
-
-	__hugebss_vma = .;
-	__hugebss_lma = .;		/* Dummy */
-	.hugebss (NOLOAD) : AT (__hugebss_lma) {
-		__hugebss_start = .;
-		*(.hugebss)
-		*(.hugebss.*)
-		__hugebss_end = .;
-	}
-	__hugebss_len = ABSOLUTE(__hugebss_end) - ABSOLUTE(__hugebss_start);
-	__hugebss_dwords = (__hugebss_len + 3) >> 2;
-
 	/* Data saved away before bss initialization */
 	. = ALIGN(128);
 
diff --git a/core/thread/exit_thread.c b/core/thread/exit_thread.c
new file mode 100644
index 00000000..d9fd83ad
--- /dev/null
+++ b/core/thread/exit_thread.c
@@ -0,0 +1,30 @@
+#include <limits.h>
+#include <stdlib.h>
+#include <klibc/compiler.h>
+#include "thread.h"
+#include "core.h"
+
+__noreturn __exit_thread(void)
+{
+    struct thread *curr = current();
+
+    cli();
+
+    /* Remove from the linked list */
+    curr->list.prev->next = curr->list.next;
+    curr->list.next->prev = curr->list.prev;
+
+    /* Free allocated stacks (note: free(NULL) is permitted and safe). */
+    free(curr->stack);
+    free(curr->rmstack);
+
+    /*
+     * Note: __schedule() can explictly handle the case where
+     * curr isn't part of the linked list anymore, as long as
+     * curr->list.next is still valid.
+     */
+    __schedule();
+
+    /* We should never get here */
+    kaboom();
+}
diff --git a/core/thread/idle_thread.c b/core/thread/idle_thread.c
new file mode 100644
index 00000000..8faa0719
--- /dev/null
+++ b/core/thread/idle_thread.c
@@ -0,0 +1,27 @@
+#include "thread.h"
+#include <limits.h>
+#include <sys/cpu.h>
+
+static void default_idle_thread_hook(void)
+{
+}
+
+void (*idle_thread_hook)(void) = default_idle_thread_hook;
+
+static void idle_thread_func(void *dummy)
+{
+    (void)dummy;
+
+    for (;;) {
+	cli();
+	idle_thread_hook();
+	__schedule();
+	asm volatile("sti ; hlt" : : : "memory");
+    }
+}
+
+void start_idle_thread(void)
+{
+    start_thread("idle", 4096, IDLE_THREAD_PRIORITY, idle_thread_func, NULL);
+}
+
diff --git a/core/thread/kill_thread.c b/core/thread/kill_thread.c
new file mode 100644
index 00000000..c22517c6
--- /dev/null
+++ b/core/thread/kill_thread.c
@@ -0,0 +1,42 @@
+#include "thread.h"
+#include <limits.h>
+
+extern void __exit_thread(void);
+typedef void (*func_ptr)(void);
+
+void kill_thread(struct thread *thread)
+{
+    irq_state_t irq;
+    struct thread_block *block;
+
+    if (thread == current())
+	__exit_thread();
+
+    irq = irq_save();
+
+    /*
+     * Muck with the stack so that the next time the thread is run then
+     * we end up going to __exit_thread.
+     */
+    thread->esp->eip = __exit_thread;
+    thread->prio = INT_MIN;
+
+    block = thread->blocked;
+    if (block) {
+	struct semaphore *sem = block->semaphore;
+	/* Remove us from the queue and increase the count */
+	block->list.next->prev = block->list.prev;
+	block->list.prev->next = block->list.next;
+	sem->count++;
+
+	thread->blocked = NULL;
+	block->timed_out = true; /* Fake an immediate timeout */
+    }
+
+    __schedule();
+
+    irq_restore(irq);
+}
+
+
+
diff --git a/core/thread/mbox.c b/core/thread/mbox.c
new file mode 100644
index 00000000..c518eeba
--- /dev/null
+++ b/core/thread/mbox.c
@@ -0,0 +1,57 @@
+/*
+ * mbox.c
+ *
+ * Simple thread mailbox interface
+ */
+
+#include "thread.h"
+#include "mbox.h"
+#include <errno.h>
+
+void mbox_init(struct mailbox *mbox, size_t size)
+{
+    sem_init(&mbox->prod_sem, size); /* All slots empty */
+    sem_init(&mbox->cons_sem, 0);    /* No slots full */
+    sem_init(&mbox->head_sem, 1);    /* Head mutex */
+    sem_init(&mbox->tail_sem, 1);    /* Tail mutex */
+
+    mbox->wrap = &mbox->data[size];
+    mbox->head = &mbox->data[0];
+    mbox->tail = &mbox->data[0];
+};
+
+int mbox_post(struct mailbox *mbox, void *msg, mstime_t timeout)
+{
+    if (sem_down(&mbox->prod_sem, timeout) == (mstime_t)-1)
+	return ENOMEM;
+    sem_down(&mbox->head_sem, 0);
+
+    *mbox->head = msg;
+    mbox->head++;
+    if (mbox->head == mbox->wrap)
+	mbox->head = &mbox->data[0];
+
+    sem_up(&mbox->head_sem);
+    sem_up(&mbox->cons_sem);
+    return 0;
+}
+
+mstime_t mbox_fetch(struct mailbox *mbox, void **msg, mstime_t timeout)
+{
+    mstime_t t;
+
+    t = sem_down(&mbox->cons_sem, timeout);
+    if (t == (mstime_t)-1)
+	return -1;
+    t += sem_down(&mbox->tail_sem, 0);
+
+    if (msg)
+	*msg = *mbox->tail;
+    mbox->tail++;
+    if (mbox->tail == mbox->wrap)
+	mbox->tail = &mbox->data[0];
+
+    sem_up(&mbox->tail_sem);
+    sem_up(&mbox->prod_sem);
+    return t;
+}
diff --git a/core/thread/root_thread.c b/core/thread/root_thread.c
new file mode 100644
index 00000000..2bba7c26
--- /dev/null
+++ b/core/thread/root_thread.c
@@ -0,0 +1,11 @@
+#include "thread.h"
+
+struct thread __root_thread = {
+    .thread_magic = THREAD_MAGIC,
+    .name = "root",
+    .list = { .next = &__root_thread.list, .prev = &__root_thread.list },
+    .blocked = NULL,
+    .prio = 0,
+};
+
+struct thread *__current = &__root_thread;
diff --git a/core/thread/schedule.c b/core/thread/schedule.c
new file mode 100644
index 00000000..5a426f11
--- /dev/null
+++ b/core/thread/schedule.c
@@ -0,0 +1,91 @@
+#include <klibc/compiler.h>
+#include <sys/cpu.h>
+#include "thread.h"
+#include "core.h"
+#include <dprintf.h>
+
+void (*sched_hook_func)(void);
+
+/*
+ * __schedule() should only be called with interrupts locked out!
+ */
+void __schedule(void)
+{
+    static bool in_sched_hook;
+    struct thread *curr = current();
+    struct thread *st, *nt, *best;
+
+#if DEBUG
+    if (__unlikely(irq_state() & 0x200)) {
+	dprintf("In __schedule with interrupts on!\n");
+	kaboom();
+    }
+#endif
+
+    /*
+     * Are we called from inside sched_hook_func()?  If so we'll
+     * schedule anyway on the way out.
+     */
+    if (in_sched_hook)
+	return;
+
+    dprintf("Schedule ");
+
+    /* Possibly update the information on which we make
+     * scheduling decisions.
+     */
+    if (sched_hook_func) {
+	in_sched_hook = true;
+	sched_hook_func();
+	in_sched_hook = false;
+    }
+
+    /*
+     * The unusual form of this walk is because we have to start with
+     * the thread *following* curr, and curr may not actually be part
+     * of the list anymore (in the case of __exit_thread).
+     */
+    best = NULL;
+    nt = st = container_of(curr->list.next, struct thread, list);
+    do {
+	if (__unlikely(nt->thread_magic != THREAD_MAGIC)) {
+	    dprintf("Invalid thread on thread list %p magic = 0x%08x\n",
+		    nt, nt->thread_magic);
+	    kaboom();
+	}
+
+	dprintf("Thread %p (%s) ", nt, nt->name);
+	if (!nt->blocked) {
+	    dprintf("runnable priority %d\n", nt->prio);
+	    if (!best || nt->prio < best->prio)
+		best = nt;
+	} else {
+	    dprintf("blocked\n");
+	}
+	nt = container_of(nt->list.next, struct thread, list);
+    } while (nt != st);
+
+    if (!best)
+	kaboom();		/* No runnable thread */
+
+    if (best != curr) {
+	uint64_t tsc;
+	
+	asm volatile("rdtsc" : "=A" (tsc));
+	
+	dprintf("@ %llu -> %p (%s)\n", tsc, best, best->name);
+	__switch_to(best);
+    } else {
+	dprintf("no change\n");
+    }
+}
+
+/*
+ * This can be called from "normal" code...
+ */
+void thread_yield(void)
+{
+    irq_state_t irq = irq_save();
+    __schedule();
+    irq_restore(irq);
+}
diff --git a/core/thread/sem_asm.S b/core/thread/sem_asm.S
new file mode 100644
index 00000000..ce67471a
--- /dev/null
+++ b/core/thread/sem_asm.S
@@ -0,0 +1,16 @@
+	.globl	sem_down
+	.type	sem_down, @function
+sem_down:
+	decl	(%eax)
+	js	__sem_down_slow
+	xorl	%eax, %eax
+	ret
+	.size	sem_down, .-sem_down
+
+	.globl	sem_up
+	.type	sem_up, @function
+sem_up:
+	incl	(%eax)
+	jle	__sem_up_slow
+	ret
+	.size	sem_up, .-sem_up
diff --git a/core/thread/semaphore.c b/core/thread/semaphore.c
new file mode 100644
index 00000000..6a2e4c13
--- /dev/null
+++ b/core/thread/semaphore.c
@@ -0,0 +1,81 @@
+#include <sys/cpu.h>
+#include "thread.h"
+
+void sem_init(struct semaphore *sem, int count)
+{
+    sem->list.next = sem->list.prev = &sem->list;
+    sem->count = count;
+}
+
+mstime_t __sem_down_slow(struct semaphore *sem, mstime_t timeout)
+{
+    irq_state_t irq;
+    mstime_t rv;
+
+    irq = irq_save();
+
+    if (sem->count >= 0) {
+	/* Something already freed the semaphore on us */
+	rv = 0;
+    } else if (timeout == -1) {
+	/* Immediate timeout */
+	sem->count++;
+	rv = -1;
+    } else {
+	/* Put the thread to sleep... */
+
+	struct thread_block block;
+	struct thread *curr = current();
+	mstime_t now = ms_timer();
+
+	block.thread     = curr;
+	block.semaphore  = sem;
+	block.block_time = now;
+	block.timeout    = timeout ? now+timeout : 0;
+	block.timed_out  = false;
+
+	curr->blocked    = &block;
+
+	/* Add to the end of the wakeup list */
+	block.list.prev       = sem->list.prev;
+	block.list.next       = &sem->list;
+	sem->list.prev        = &block.list;
+	block.list.prev->next = &block.list;
+
+	__schedule();
+
+	rv = block.timed_out ? -1 : ms_timer() - block.block_time;
+    }
+
+    irq_restore(irq);
+    return rv;
+}
+
+void __sem_up_slow(struct semaphore *sem)
+{
+    irq_state_t irq;
+    struct thread_list *l;
+
+    irq = irq_save();
+
+    /*
+     * It's possible that something did a down on the semaphore, but
+     * didn't get to add themselves to the queue just yet.  In that case
+     * we don't have to do anything, since the bailout clause in
+     * __sem_down_slow will take care of it.
+     */
+    l = sem->list.next;
+    if (l != &sem->list) {
+	struct thread_block *block;
+	block = container_of(l, struct thread_block, list);
+
+	sem->list.next = block->list.next;
+	block->list.next->prev = &sem->list;
+
+	block->thread->blocked = NULL;
+
+	__schedule();
+    }
+
+    irq_restore(irq);
+}
diff --git a/core/thread/start_thread.c b/core/thread/start_thread.c
new file mode 100644
index 00000000..2e4320a4
--- /dev/null
+++ b/core/thread/start_thread.c
@@ -0,0 +1,69 @@
+#include <string.h>
+#include <stdlib.h>
+#include <com32.h>
+#include "core.h"
+#include "thread.h"
+
+#define REAL_MODE_STACK_SIZE	4096
+#define MIN_STACK_SIZE		16384
+#define THREAD_ALIGN		64 	/* Thread alignment */
+
+extern void __start_thread(void);
+
+struct thread *start_thread(const char *name, size_t stack_size, int prio,
+			    void (*start_func)(void *), void *func_arg)
+{
+    irq_state_t irq;
+    struct thread *curr, *t;
+    char *stack, *rmstack;
+    const size_t thread_mask = THREAD_ALIGN - 1;
+    struct thread_stack *sp;
+
+    if (stack_size < MIN_STACK_SIZE)
+	stack_size = MIN_STACK_SIZE;
+
+    stack_size = (stack_size + thread_mask) & ~thread_mask;
+    stack = malloc(stack_size + sizeof(struct thread));
+    if (!stack)
+	return NULL;
+    rmstack = lmalloc(REAL_MODE_STACK_SIZE);
+    if (!rmstack) {
+	free(stack);
+	return NULL;
+    }
+
+    t = (struct thread *)stack;
+    memset(t, 0, sizeof *t);
+    t->stack   = stack;
+    t->rmstack = rmstack;
+    stack += sizeof(struct thread);
+
+    /* sp allocated from the end of the stack */
+    sp = (struct thread_stack *)(stack + stack_size) - 1;
+    t->esp = sp;
+
+    sp->errno = 0;
+    sp->rmss = SEG(rmstack);
+    sp->rmsp = REAL_MODE_STACK_SIZE;
+    sp->esi = (size_t)start_func;
+    sp->edi = (size_t)func_arg;
+    sp->ebx = irq_state();	/* Inherit the IRQ state from the spawner */
+    sp->eip = __start_thread;
+    t->prio = prio;
+    t->name = name;
+
+    irq = irq_save();
+    curr = current();
+
+    t->thread_magic    = THREAD_MAGIC;
+
+    t->list.prev       = &curr->list;
+    t->list.next       = curr->list.next;
+    curr->list.next    = &t->list;
+    t->list.next->prev = &t->list;
+
+    __schedule();
+
+    irq_restore(irq);
+    return t;
+}
diff --git a/core/thread/thread_asm.S b/core/thread/thread_asm.S
new file mode 100644
index 00000000..ec3e0add
--- /dev/null
+++ b/core/thread/thread_asm.S
@@ -0,0 +1,37 @@
+	.globl	__switch_to
+	.type	__switch_to, @function
+__switch_to:
+	movl	__current, %edx
+	pushl	%ebx
+	pushl	%ebp
+	pushl	%esi
+	pushl	%edi
+	pushl	RealModeSSSP
+	pushl	errno			/* Hack! */
+	movl	%esp, (%edx)
+
+	movl	%eax, __current
+	movl	(%eax), %esp
+	popl	errno
+	popl	RealModeSSSP
+	popl	%edi
+	popl	%esi
+	popl	%ebp
+	popl	%ebx
+	ret
+	.size	__switch_to, .-__switch_to
+
+	.globl	__start_thread
+	.type	__start_thread, @function
+__start_thread:
+	movl	%edi, %eax		/* Thread function argument */
+
+	pushl	$0			/* For gdb's benefit */
+	movl	%esp, %ebp		/* For gdb's benefit */
+
+	pushl	%ebx			/* Set up the flags/interrupt state */
+	popfl
+
+	call	*%esi			/* Run the desired function */
+	jmp	__exit_thread		/* If we get here, kill the thread */
+	.size	__start_thread, .-__start_thread
diff --git a/core/thread/timeout.c b/core/thread/timeout.c
new file mode 100644
index 00000000..409ad6d7
--- /dev/null
+++ b/core/thread/timeout.c
@@ -0,0 +1,41 @@
+/*
+ * timeout.c
+ *
+ */
+
+#include "thread.h"
+
+/*
+ * __thread_process_timeouts()
+ *
+ * Look for threads that have timed out.  This should be called
+ * under interrupt lock, before calling __schedule().
+ */
+void __thread_process_timeouts(void)
+{
+    struct thread *curr = current();
+    struct thread_list *tp;
+    struct thread *t;
+    mstime_t now = ms_timer();
+    struct thread_block *block;
+    mstime_t timeout;
+
+    /* The current thread is obviously running, so no need to check... */
+    for (tp = curr->list.next; tp != &curr->list; tp = tp->next) {
+	t = container_of(tp, struct thread, list);
+	if ((block = t->blocked) && (timeout = block->timeout)) {
+	    if ((mstimediff_t)(timeout - now) <= 0) {
+		struct semaphore *sem = block->semaphore;
+		/* Remove us from the queue and increase the count */
+		block->list.next->prev = block->list.prev;
+		block->list.prev->next = block->list.next;
+		sem->count++;
+
+		t->blocked = NULL;
+		block->timed_out = true;
+
+		__schedule();	/* Normally sets just __need_schedule */
+	    }
+	}
+    }
+}
diff --git a/core/vkernel.inc b/core/vkernel.inc
new file mode 100644
index 00000000..278344e4
--- /dev/null
+++ b/core/vkernel.inc
@@ -0,0 +1,35 @@
+;; -----------------------------------------------------------------------
+;;
+;;   Copyright 1994-2008 H. Peter Anvin - All Rights Reserved
+;;   Copyright 2009-2011 Intel Corporation; author: H. Peter Anvin
+;;
+;;   This program is free software; you can redistribute it and/or modify
+;;   it under the terms of the GNU General Public License as published by
+;;   the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+;;   Boston MA 02110-1301, USA; either version 2 of the License, or
+;;   (at your option) any later version; incorporated herein by reference.
+;;
+;; -----------------------------------------------------------------------
+
+%ifndef _VKERNEL_INC
+%define _VKERNEL_INC
+
+;
+; The following structure is used for "virtual kernels"; i.e. LILO-style
+; option labels.  The options we permit here are `kernel' and `append
+; Since there is no room in the bottom 64K for all of these, we
+; stick them in high memory and copy them down before we need them.
+;
+		struc vkernel
+vk_vname:	resb FILENAME_MAX	; Virtual name **MUST BE FIRST!**
+vk_rname:	resb FILENAME_MAX	; Real name
+vk_sysappend:	resd 1			; Sysappend option
+vk_appendlen:	resw 1
+vk_type:	resb 1			; Type of file
+		alignb 4
+vk_append:	resb max_cmd_len+1	; Command line
+		alignb 4
+vk_end:		equ $			; Should be <= vk_size
+		endstruc
+
+%endif ; _VKERNEL_INC
diff --git a/doc/cptime.txt b/doc/cptime.txt
new file mode 100644
index 00000000..982dbf7c
--- /dev/null
+++ b/doc/cptime.txt
@@ -0,0 +1,50 @@
+= cptime.c32(1) =
+:doctype: manpage
+:author:  Gene Cumm
+:email:   gene.cumm@gmail.com
+:revdate: 2011-12-17
+
+
+== NAME ==
+cptime.c32 - times the copy off (read) of a file
+
+
+== SYNOPSIS ==
+*cptime.c32* ['OPTIONS'] 'FILE'...
+
+
+== DESCRIPTION ==
+Times the copy off (read) of a file, optionally computes/displays
+transfer rates(on by default) with an adjustable transfer size and
+maximum transfer length.
+
+
+== OPTIONS ==
+*-b* 'SIZE'::
+    use 'SIZE' for transfer size; defaults to 2048 for COM32
+
+*-l*::
+    long output mode; default; reverses *-s*
+
+*-n* 'LEN'::
+    maximum length to fetch; defaults to whole file
+
+*-q*::
+    quiet (normal/non-verbose) mode; default; reverses *-v*
+
+*-s*::
+    simple output mode
+
+*-v*::
+    verbose mode
+
+The same mode is used for all files.
+
+
+== AUTHOR ==
+{author} <{email}>
+
+== COPYRIGHT ==
+Copyright \(C) 2011 {author}. Free use of this software is granted under
+the terms of the GNU General Public License (GPL).
+
diff --git a/doc/pxelinux.txt b/doc/pxelinux.txt
index 69c1a645..4dbb152e 100644
--- a/doc/pxelinux.txt
+++ b/doc/pxelinux.txt
@@ -3,12 +3,16 @@
     A bootloader for Linux using the PXE network booting protocol
 
        Copyright 1994-2008 H. Peter Anvin - All Rights Reserved
+       Copyright 2009-2011 Intel Corporation; author: H. Peter Anvin
 
 This program is provided under the terms of the GNU General Public
 License, version 2 or, at your option, any later version.  There is no
 warranty, neither expressed nor implied, to the function of this
 program.  Please see the included file COPYING for details.
 
+This documentation file is slightly out of date; please check the NEWS
+file for changes.
+
 ----------------------------------------------------------------------
 
 PXELINUX is a Syslinux derivative, for booting Linux off a network
@@ -99,25 +103,22 @@ boot, if you have such a setup.  MTFTP server setup is beyond the
 scope of this document.
 
 
-    ++++ gPXE-ENHANCED VARIANTS ++++
+    ++++ HTTP AND FTP DOWNLOADS ++++
 
-gPXE can be used to enhance PXELINUX's functionality to also include
-HTTP transfers, greatly increasing load speed and allowing for standard
-HTTP scripts to present PXELINUX's configuration file.  pxelinux.0 is
-the plain variant.  gpxelinux.0 (included as of 3.70) is gPXE's
-undionly.kkpxe, pxelinux.0 and a script to run pxelinux.0.  gpxelinuxk.0
-(included as of 4.04) is gPXE's undionly.kpxe, pxelinux.0 and a script
-to run pxelinux.0.  gpxelinuxk.0 should only be used with systems that
-are incompatible with gpxelinux.0 as it prevents certain functionality
-from working (LOCALBOOT with a type not equal to -1) and is incompatible
-with certain hardware, PXE stacks and network setups.
+Since version 5.10, native pxelinux.0 can support HTTP and FTP
+transfers, greatly increasing load speed and allowing for standard
+HTTP scripts to present PXELINUX's configuration file.  To use http or
+ftp, use standard URL syntax as filename; use the DHCP options below
+to transmit a suitable URL prefix to the client, or use the
+"pxelinux-options" tool provided in the utils directory to program it
+directly into the pxelinux.0 file.
 
 
     ++++ SETTING UP THE TFTP SERVER ++++
 
-PXELINUX currently requires that the boot server has a TFTP server
-which supports the "tsize" TFTP option (RFC 1784/RFC 2349).  The
-"tftp-hpa" TFTP server, which support options, is available at:
+For best results, use a TFTP server which supports the "tsize" TFTP
+option (RFC 1784/RFC 2349).  The "tftp-hpa" TFTP server, which support
+options, is available at:
 
 	http://www.kernel.org/pub/software/network/tftp/
 	ftp://www.kernel.org/pub/software/network/tftp/
@@ -343,7 +344,15 @@ If you used this from a client whose Ethernet address was
 "/tftpboot/pxelinux.cfg/1:58:fa:84:cf:55:e".
 
 
-    ++++ ALTERNATE TFTP SERVERS ++++
+    ++++ HARDCODED OPTIONS ++++
+
+Since version 3.83, the program "pxelinux-options" can be used to
+hard-code DHCP options into the pxelinux.0 image file; this is
+sometimes useful when the DHCP server is under different
+administrative control.
+
+
+    ++++ ALTERNATE TFTP SERVERS AND URL SYNTAX ++++
 
 PXELINUX supports the following special pathname conventions:
 
@@ -365,6 +374,8 @@ usage.  However, if you happen to have an environment for which the
 special treatment of :: is a problem, please contact the Syslinux
 mailing list.
 
+Since version 4.00, PXELINUX also supports standard URL syntax.
+
 
     ++++ SOME NOTES ++++
 
diff --git a/doc/syslinux.txt b/doc/syslinux.txt
index caf3a06c..a4b201fd 100644
--- a/doc/syslinux.txt
+++ b/doc/syslinux.txt
@@ -153,9 +153,12 @@ APPEND options...
         usually permitting explicitly entered kernel options to override
         them.  This is the equivalent of the LILO "append" option.
 
-IPAPPEND flag_val			[PXELINUX only]
-	The IPAPPEND option is available only on PXELINUX.  The
-	flag_val is an OR of the following options:
+SYSAPPEND bitmask
+IPAPPEND bitmask
+
+	The SYSAPPEND option was introduced in Syslinux 5.10; it is an
+	enhancement of a previous option IPAPPEND which was only
+	available on PXELINUX.
 
 	1: indicates that an option of the following format
 	should be generated and added to the kernel command line:
@@ -169,6 +172,8 @@ IPAPPEND flag_val			[PXELINUX only]
 	the lease acquired by the PXE BIOS will expire, making the
 	IP address available for reuse by the DHCP server.
 
+	This option is empty for non-PXELINUX.
+
 	2: indicates that an option of the following format
 	should be generated and added to the kernel command line:
 
@@ -180,6 +185,8 @@ IPAPPEND flag_val			[PXELINUX only]
 	This allows an initrd program to determine from which
 	interface the system booted.
 
+	This option is empty for non-PXELINUX.
+
 	4: indicates that an option of the following format
 	should be generated and added to the kernel command line:
 
@@ -187,14 +194,105 @@ IPAPPEND flag_val			[PXELINUX only]
 
 	... in lower case hexadecimal in the format normally used for
 	UUIDs (same as for the configuration file; see pxelinux.txt.)
+	This may not be available if no valid UUID is found on the
+	system.
+
+	8: indicate the CPU family and certain particularly
+	significant CPU feature bits:
+
+		CPU=<family><features>
+
+	The <family> is a single digit from 3 (i386) to 6 (i686 or
+	higher.)  The following CPU feature are currently reported;
+	additional flags may be added in the future:
+
+		P	Physical Address Extension (PAE)
+		V	Intel Virtualization Technology (VT/VMX)
+		T	Intel Trusted Exection Technology (TXT/SMX)
+		X	Execution Disable (XD/NX)
+		L	Long Mode (x86-64)
+		S	AMD SMX virtualization
+	
+	This was added in 5.10.
+
+	The following strings are derived from DMI/SMBIOS information
+	if available; these are all new in version 5.10:
+	
+	Bit	String		Significance
+	-------------------------------------------------------------
+	0x00010	SYSVENDOR=	System vendor name
+	0x00020	SYSPRODUCT=	System product name
+	0x00040	SYSVERSION=	System version
+	0x00080	SYSSERIAL=	System serial number
+	0x00100	SYSSKU=		System SKU
+	0x00200	SYSFAMILY=	System family
+	0x00400	MBVENDOR=	Motherboard vendor name
+	0x00800	MBVERSION=	Motherboard version
+	0x01000	MBSERIAL=	Motherboard serial number
+	0x02000	MBASSET=	Motherboard asset tag
+	0x04000 BIOSVENDOR=	BIOS vendor name
+	0x08000	BIOSVERSION=	BIOS version
+	0x10000	SYSFF=		System form factor
+
+	If these strings contain whitespace they it is replaced with
+	underscores (_).
+
+	The system form factor value is a number defined in the SMBIOS
+	specification, available at http://www.dmtf.org/.  As of
+	version 2.7.1 of the specification, the following values are
+	defined:
+
+	  1	Other
+	  2	Unknown
+	  3	Desktop
+	  4	Low profile desktop
+	  5	Pizza box
+	  6	Mini tower
+	  7	Tower
+	  8	Portble
+	  9	Laptop
+	 10	Notebook
+	 11	Handheld
+	 12	Docking station
+	 13	All-in-one
+	 14	Subnotebook
+	 15	Space-saving
+	 16	Lunch box
+	 17	Main server chassis
+	 18	Expansion chassis
+	 19	Subchassis
+	 20	Bus expansion chassis
+	 21	Peripheral chassis
+	 22	RAID chassis
+	 23	Rack mount chasss
+	 24	Sealed-case PC
+	 25	Multi-system chassis
+	 26	Compact PCI
+	 27	Advanced TCI
+	 28	Blade
+	 29	Blade enclosure
+
+SENDCOOKIES bitmask			[PXELINUX only]
+
+	When downloading files over http, the SYSAPPEND strings are
+	prepended with _Syslinux_ and sent to the server as cookies.
+	The cookies are URL-encoded; whitespace is *not* replaced with
+	underscores.
+
+	This command limits the cookies send; 0 means no cookies.  The
+	default is -1, meaning send all cookies.
+
+	This option is "sticky" and is not automatically reset when
+	loading a new configuration file with the CONFIG command.
 
 LABEL label
     KERNEL image
     APPEND options...
-    IPAPPEND flag_val			[PXELINUX only]
+    SYSAPPEND flag_val			[5.10+]
+    IPAPPEND flag_val			[5.10+ or PXELINUX only]
 	Indicates that if "label" is entered as the kernel to boot,
         Syslinux should instead boot "image", and the specified APPEND
-	and IPAPPEND options should be used instead of the ones
+	and SYSAPPEND options should be used instead of the ones
         specified in the global section of the file (before the first
         LABEL command.)  The default for "image" is the same as
         "label", and if no APPEND is given the default is to use the
@@ -370,6 +468,9 @@ SERIAL port [[baudrate] flowcontrol]
 	responsiveness without setting the NOHALT option, but could
 	potentially cause problems with buggy BIOSes.
 
+	This option is "sticky" and is not automatically reset when
+	loading a new configuration file with the CONFIG command.
+
 NOHALT flag_val
 	If flag_val is 1, don't halt the processor while idle.
 	Halting the processor while idle significantly reduces the
diff --git a/mk/syslinux.mk b/mk/syslinux.mk
index 1378b6d5..2e12072e 100644
--- a/mk/syslinux.mk
+++ b/mk/syslinux.mk
@@ -32,8 +32,13 @@ COM32DIR = $(AUXDIR)/com32
 BOOTDIR	    = /boot
 EXTLINUXDIR = $(BOOTDIR)/extlinux
 
+ifdef DEBUG
+# This allows DEBUGOPT to be set from the command line
+DEBUGOPT = -DDEBUG=$(DEBUG)
+endif
+
 NASM	 = nasm
-NASMOPT  = -Ox
+NASMOPT  = -Ox $(DEBUGOPT)
 
 PERL	 = perl
 PYTHON	 = python
@@ -68,9 +73,7 @@ WGET	 = wget
 com32    = $(topdir)/com32
 
 # Common warnings we want for all gcc-generated code
-GCCWARN := -W -Wall -Wstrict-prototypes
-# Extremely useful variant for debugging...
-#GCCWARN += -Wno-clobbered -Werror
+GCCWARN  = -W -Wall -Wstrict-prototypes $(DEBUGOPT)
 
 # Common stanza to make gcc generate .*.d dependency files
 MAKEDEPS = -Wp,-MT,$@,-MD,$(dir $@).$(notdir $@).d
diff --git a/version b/version
index e5c9c4cd..7d837934 100644
--- a/version
+++ b/version
@@ -1 +1 @@
-5.02 2013
+5.10 2013