[NETFILTER]: Add nf_conntrack subsystem.

The existing connection tracking subsystem in netfilter can only
handle ipv4.  There were basically two choices present to add
connection tracking support for ipv6.  We could either duplicate all
of the ipv4 connection tracking code into an ipv6 counterpart, or (the
choice taken by these patches) we could design a generic layer that
could handle both ipv4 and ipv6 and thus requiring only one sub-protocol
(TCP, UDP, etc.) connection tracking helper module to be written.

In fact nf_conntrack is capable of working with any layer 3
protocol.

The existing ipv4 specific conntrack code could also not deal
with the pecularities of doing connection tracking on ipv6,
which is also cured here.  For example, these issues include:

1) ICMPv6 handling, which is used for neighbour discovery in
   ipv6 thus some messages such as these should not participate
   in connection tracking since effectively they are like ARP
   messages

2) fragmentation must be handled differently in ipv6, because
   the simplistic "defrag, connection track and NAT, refrag"
   (which the existing ipv4 connection tracking does) approach simply
   isn't feasible in ipv6

3) ipv6 extension header parsing must occur at the correct spots
   before and after connection tracking decisions, and there were
   no provisions for this in the existing connection tracking
   design

4) ipv6 has no need for stateful NAT

The ipv4 specific conntrack layer is kept around, until all of
the ipv4 specific conntrack helpers are ported over to nf_conntrack
and it is feature complete.  Once that occurs, the old conntrack
stuff will get placed into the feature-removal-schedule and we will
fully kill it off 6 months later.

Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

1 files changed, 670 insertions, 0 deletions

diff --git a/net/netfilter/nf_conntrack_proto_sctp.c b/net/netfilter/nf_conntrack_proto_sctp.c
new file mode 100644
index 00000000000000..3a600f77b4e0c3
--- /dev/null
+++ b/net/netfilter/nf_conntrack_proto_sctp.c
@@ -0,0 +1,670 @@
+/*
+ * Connection tracking protocol helper module for SCTP.
+ * 
+ * SCTP is defined in RFC 2960. References to various sections in this code 
+ * are to this RFC.
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 17 Oct 2004: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
+ *	- enable working with L3 protocol independent connection tracking.
+ *
+ * Derived from net/ipv4/ip_conntrack_sctp.c
+ */
+
+/*
+ * Added support for proc manipulation of timeouts.
+ */
+
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/timer.h>
+#include <linux/netfilter.h>
+#include <linux/module.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/sctp.h>
+#include <linux/string.h>
+#include <linux/seq_file.h>
+
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_protocol.h>
+
+#if 0
+#define DEBUGP(format, ...) printk(format, ## __VA_ARGS__)
+#else
+#define DEBUGP(format, args...)
+#endif
+
+/* Protects conntrack->proto.sctp */
+static DEFINE_RWLOCK(sctp_lock);
+
+/* FIXME: Examine ipfilter's timeouts and conntrack transitions more
+   closely.  They're more complex. --RR 
+
+   And so for me for SCTP :D -Kiran */
+
+static const char *sctp_conntrack_names[] = {
+	"NONE",
+	"CLOSED",
+	"COOKIE_WAIT",
+	"COOKIE_ECHOED",
+	"ESTABLISHED",
+	"SHUTDOWN_SENT",
+	"SHUTDOWN_RECD",
+	"SHUTDOWN_ACK_SENT",
+};
+
+#define SECS  * HZ
+#define MINS  * 60 SECS
+#define HOURS * 60 MINS
+#define DAYS  * 24 HOURS
+
+static unsigned long nf_ct_sctp_timeout_closed            =  10 SECS;
+static unsigned long nf_ct_sctp_timeout_cookie_wait       =   3 SECS;
+static unsigned long nf_ct_sctp_timeout_cookie_echoed     =   3 SECS;
+static unsigned long nf_ct_sctp_timeout_established       =   5 DAYS;
+static unsigned long nf_ct_sctp_timeout_shutdown_sent     = 300 SECS / 1000;
+static unsigned long nf_ct_sctp_timeout_shutdown_recd     = 300 SECS / 1000;
+static unsigned long nf_ct_sctp_timeout_shutdown_ack_sent =   3 SECS;
+
+static unsigned long * sctp_timeouts[]
+= { NULL,                                  /* SCTP_CONNTRACK_NONE  */
+    &nf_ct_sctp_timeout_closed,	           /* SCTP_CONNTRACK_CLOSED */
+    &nf_ct_sctp_timeout_cookie_wait,       /* SCTP_CONNTRACK_COOKIE_WAIT */
+    &nf_ct_sctp_timeout_cookie_echoed,     /* SCTP_CONNTRACK_COOKIE_ECHOED */
+    &nf_ct_sctp_timeout_established,       /* SCTP_CONNTRACK_ESTABLISHED */
+    &nf_ct_sctp_timeout_shutdown_sent,     /* SCTP_CONNTRACK_SHUTDOWN_SENT */
+    &nf_ct_sctp_timeout_shutdown_recd,     /* SCTP_CONNTRACK_SHUTDOWN_RECD */
+    &nf_ct_sctp_timeout_shutdown_ack_sent  /* SCTP_CONNTRACK_SHUTDOWN_ACK_SENT */
+ };
+
+#define sNO SCTP_CONNTRACK_NONE
+#define	sCL SCTP_CONNTRACK_CLOSED
+#define	sCW SCTP_CONNTRACK_COOKIE_WAIT
+#define	sCE SCTP_CONNTRACK_COOKIE_ECHOED
+#define	sES SCTP_CONNTRACK_ESTABLISHED
+#define	sSS SCTP_CONNTRACK_SHUTDOWN_SENT
+#define	sSR SCTP_CONNTRACK_SHUTDOWN_RECD
+#define	sSA SCTP_CONNTRACK_SHUTDOWN_ACK_SENT
+#define	sIV SCTP_CONNTRACK_MAX
+
+/* 
+	These are the descriptions of the states:
+
+NOTE: These state names are tantalizingly similar to the states of an 
+SCTP endpoint. But the interpretation of the states is a little different,
+considering that these are the states of the connection and not of an end 
+point. Please note the subtleties. -Kiran
+
+NONE              - Nothing so far.
+COOKIE WAIT       - We have seen an INIT chunk in the original direction, or also 
+                    an INIT_ACK chunk in the reply direction.
+COOKIE ECHOED     - We have seen a COOKIE_ECHO chunk in the original direction.
+ESTABLISHED       - We have seen a COOKIE_ACK in the reply direction.
+SHUTDOWN_SENT     - We have seen a SHUTDOWN chunk in the original direction.
+SHUTDOWN_RECD     - We have seen a SHUTDOWN chunk in the reply directoin.
+SHUTDOWN_ACK_SENT - We have seen a SHUTDOWN_ACK chunk in the direction opposite
+                    to that of the SHUTDOWN chunk.
+CLOSED            - We have seen a SHUTDOWN_COMPLETE chunk in the direction of 
+                    the SHUTDOWN chunk. Connection is closed.
+*/
+
+/* TODO
+ - I have assumed that the first INIT is in the original direction. 
+ This messes things when an INIT comes in the reply direction in CLOSED
+ state.
+ - Check the error type in the reply dir before transitioning from 
+cookie echoed to closed.
+ - Sec 5.2.4 of RFC 2960
+ - Multi Homing support.
+*/
+
+/* SCTP conntrack state transitions */
+static enum sctp_conntrack sctp_conntracks[2][9][SCTP_CONNTRACK_MAX] = {
+	{
+/*	ORIGINAL	*/
+/*                  sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA */
+/* init         */ {sCW, sCW, sCW, sCE, sES, sSS, sSR, sSA},
+/* init_ack     */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA},
+/* abort        */ {sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
+/* shutdown     */ {sCL, sCL, sCW, sCE, sSS, sSS, sSR, sSA},
+/* shutdown_ack */ {sSA, sCL, sCW, sCE, sES, sSA, sSA, sSA},
+/* error        */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA},/* Cant have Stale cookie*/
+/* cookie_echo  */ {sCL, sCL, sCE, sCE, sES, sSS, sSR, sSA},/* 5.2.4 - Big TODO */
+/* cookie_ack   */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA},/* Cant come in orig dir */
+/* shutdown_comp*/ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sCL}
+	},
+	{
+/*	REPLY	*/
+/*                  sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA */
+/* init         */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA},/* INIT in sCL Big TODO */
+/* init_ack     */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA},
+/* abort        */ {sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
+/* shutdown     */ {sIV, sCL, sCW, sCE, sSR, sSS, sSR, sSA},
+/* shutdown_ack */ {sIV, sCL, sCW, sCE, sES, sSA, sSA, sSA},
+/* error        */ {sIV, sCL, sCW, sCL, sES, sSS, sSR, sSA},
+/* cookie_echo  */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA},/* Cant come in reply dir */
+/* cookie_ack   */ {sIV, sCL, sCW, sES, sES, sSS, sSR, sSA},
+/* shutdown_comp*/ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sCL}
+	}
+};
+
+static int sctp_pkt_to_tuple(const struct sk_buff *skb,
+			     unsigned int dataoff,
+			     struct nf_conntrack_tuple *tuple)
+{
+	sctp_sctphdr_t _hdr, *hp;
+
+	DEBUGP(__FUNCTION__);
+	DEBUGP("\n");
+
+	/* Actually only need first 8 bytes. */
+	hp = skb_header_pointer(skb, dataoff, 8, &_hdr);
+	if (hp == NULL)
+		return 0;
+
+	tuple->src.u.sctp.port = hp->source;
+	tuple->dst.u.sctp.port = hp->dest;
+	return 1;
+}
+
+static int sctp_invert_tuple(struct nf_conntrack_tuple *tuple,
+			     const struct nf_conntrack_tuple *orig)
+{
+	DEBUGP(__FUNCTION__);
+	DEBUGP("\n");
+
+	tuple->src.u.sctp.port = orig->dst.u.sctp.port;
+	tuple->dst.u.sctp.port = orig->src.u.sctp.port;
+	return 1;
+}
+
+/* Print out the per-protocol part of the tuple. */
+static int sctp_print_tuple(struct seq_file *s,
+			    const struct nf_conntrack_tuple *tuple)
+{
+	DEBUGP(__FUNCTION__);
+	DEBUGP("\n");
+
+	return seq_printf(s, "sport=%hu dport=%hu ",
+			  ntohs(tuple->src.u.sctp.port),
+			  ntohs(tuple->dst.u.sctp.port));
+}
+
+/* Print out the private part of the conntrack. */
+static int sctp_print_conntrack(struct seq_file *s,
+				const struct nf_conn *conntrack)
+{
+	enum sctp_conntrack state;
+
+	DEBUGP(__FUNCTION__);
+	DEBUGP("\n");
+
+	read_lock_bh(&sctp_lock);
+	state = conntrack->proto.sctp.state;
+	read_unlock_bh(&sctp_lock);
+
+	return seq_printf(s, "%s ", sctp_conntrack_names[state]);
+}
+
+#define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count)	\
+for (offset = dataoff + sizeof(sctp_sctphdr_t), count = 0;		\
+	offset < skb->len &&						\
+	(sch = skb_header_pointer(skb, offset, sizeof(_sch), &_sch));	\
+	offset += (htons(sch->length) + 3) & ~3, count++)
+
+/* Some validity checks to make sure the chunks are fine */
+static int do_basic_checks(struct nf_conn *conntrack,
+			   const struct sk_buff *skb,
+			   unsigned int dataoff,
+			   char *map)
+{
+	u_int32_t offset, count;
+	sctp_chunkhdr_t _sch, *sch;
+	int flag;
+
+	DEBUGP(__FUNCTION__);
+	DEBUGP("\n");
+
+	flag = 0;
+
+	for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
+		DEBUGP("Chunk Num: %d  Type: %d\n", count, sch->type);
+
+		if (sch->type == SCTP_CID_INIT 
+			|| sch->type == SCTP_CID_INIT_ACK
+			|| sch->type == SCTP_CID_SHUTDOWN_COMPLETE) {
+			flag = 1;
+		}
+
+		/* Cookie Ack/Echo chunks not the first OR 
+		   Init / Init Ack / Shutdown compl chunks not the only chunks */
+		if ((sch->type == SCTP_CID_COOKIE_ACK 
+			|| sch->type == SCTP_CID_COOKIE_ECHO
+			|| flag)
+		     && count !=0 ) {
+			DEBUGP("Basic checks failed\n");
+			return 1;
+		}
+
+		if (map) {
+			set_bit(sch->type, (void *)map);
+		}
+	}
+
+	DEBUGP("Basic checks passed\n");
+	return 0;
+}
+
+static int new_state(enum ip_conntrack_dir dir,
+		     enum sctp_conntrack cur_state,
+		     int chunk_type)
+{
+	int i;
+
+	DEBUGP(__FUNCTION__);
+	DEBUGP("\n");
+
+	DEBUGP("Chunk type: %d\n", chunk_type);
+
+	switch (chunk_type) {
+		case SCTP_CID_INIT: 
+			DEBUGP("SCTP_CID_INIT\n");
+			i = 0; break;
+		case SCTP_CID_INIT_ACK: 
+			DEBUGP("SCTP_CID_INIT_ACK\n");
+			i = 1; break;
+		case SCTP_CID_ABORT: 
+			DEBUGP("SCTP_CID_ABORT\n");
+			i = 2; break;
+		case SCTP_CID_SHUTDOWN: 
+			DEBUGP("SCTP_CID_SHUTDOWN\n");
+			i = 3; break;
+		case SCTP_CID_SHUTDOWN_ACK: 
+			DEBUGP("SCTP_CID_SHUTDOWN_ACK\n");
+			i = 4; break;
+		case SCTP_CID_ERROR: 
+			DEBUGP("SCTP_CID_ERROR\n");
+			i = 5; break;
+		case SCTP_CID_COOKIE_ECHO: 
+			DEBUGP("SCTP_CID_COOKIE_ECHO\n");
+			i = 6; break;
+		case SCTP_CID_COOKIE_ACK: 
+			DEBUGP("SCTP_CID_COOKIE_ACK\n");
+			i = 7; break;
+		case SCTP_CID_SHUTDOWN_COMPLETE: 
+			DEBUGP("SCTP_CID_SHUTDOWN_COMPLETE\n");
+			i = 8; break;
+		default:
+			/* Other chunks like DATA, SACK, HEARTBEAT and
+			its ACK do not cause a change in state */
+			DEBUGP("Unknown chunk type, Will stay in %s\n", 
+						sctp_conntrack_names[cur_state]);
+			return cur_state;
+	}
+
+	DEBUGP("dir: %d   cur_state: %s  chunk_type: %d  new_state: %s\n", 
+			dir, sctp_conntrack_names[cur_state], chunk_type,
+			sctp_conntrack_names[sctp_conntracks[dir][i][cur_state]]);
+
+	return sctp_conntracks[dir][i][cur_state];
+}
+
+/* Returns verdict for packet, or -1 for invalid. */
+static int sctp_packet(struct nf_conn *conntrack,
+		       const struct sk_buff *skb,
+		       unsigned int dataoff,
+		       enum ip_conntrack_info ctinfo,
+		       int pf,
+		       unsigned int hooknum)
+{
+	enum sctp_conntrack newconntrack, oldsctpstate;
+	sctp_sctphdr_t _sctph, *sh;
+	sctp_chunkhdr_t _sch, *sch;
+	u_int32_t offset, count;
+	char map[256 / sizeof (char)] = {0};
+
+	DEBUGP(__FUNCTION__);
+	DEBUGP("\n");
+
+	sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
+	if (sh == NULL)
+		return -1;
+
+	if (do_basic_checks(conntrack, skb, dataoff, map) != 0)
+		return -1;
+
+	/* Check the verification tag (Sec 8.5) */
+	if (!test_bit(SCTP_CID_INIT, (void *)map)
+		&& !test_bit(SCTP_CID_SHUTDOWN_COMPLETE, (void *)map)
+		&& !test_bit(SCTP_CID_COOKIE_ECHO, (void *)map)
+		&& !test_bit(SCTP_CID_ABORT, (void *)map)
+		&& !test_bit(SCTP_CID_SHUTDOWN_ACK, (void *)map)
+		&& (sh->vtag != conntrack->proto.sctp.vtag[CTINFO2DIR(ctinfo)])) {
+		DEBUGP("Verification tag check failed\n");
+		return -1;
+	}
+
+	oldsctpstate = newconntrack = SCTP_CONNTRACK_MAX;
+	for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
+		write_lock_bh(&sctp_lock);
+
+		/* Special cases of Verification tag check (Sec 8.5.1) */
+		if (sch->type == SCTP_CID_INIT) {
+			/* Sec 8.5.1 (A) */
+			if (sh->vtag != 0) {
+				write_unlock_bh(&sctp_lock);
+				return -1;
+			}
+		} else if (sch->type == SCTP_CID_ABORT) {
+			/* Sec 8.5.1 (B) */
+			if (!(sh->vtag == conntrack->proto.sctp.vtag[CTINFO2DIR(ctinfo)])
+				&& !(sh->vtag == conntrack->proto.sctp.vtag
+							[1 - CTINFO2DIR(ctinfo)])) {
+				write_unlock_bh(&sctp_lock);
+				return -1;
+			}
+		} else if (sch->type == SCTP_CID_SHUTDOWN_COMPLETE) {
+			/* Sec 8.5.1 (C) */
+			if (!(sh->vtag == conntrack->proto.sctp.vtag[CTINFO2DIR(ctinfo)])
+				&& !(sh->vtag == conntrack->proto.sctp.vtag
+							[1 - CTINFO2DIR(ctinfo)] 
+					&& (sch->flags & 1))) {
+				write_unlock_bh(&sctp_lock);
+				return -1;
+			}
+		} else if (sch->type == SCTP_CID_COOKIE_ECHO) {
+			/* Sec 8.5.1 (D) */
+			if (!(sh->vtag == conntrack->proto.sctp.vtag[CTINFO2DIR(ctinfo)])) {
+				write_unlock_bh(&sctp_lock);
+				return -1;
+			}
+		}
+
+		oldsctpstate = conntrack->proto.sctp.state;
+		newconntrack = new_state(CTINFO2DIR(ctinfo), oldsctpstate, sch->type);
+
+		/* Invalid */
+		if (newconntrack == SCTP_CONNTRACK_MAX) {
+			DEBUGP("nf_conntrack_sctp: Invalid dir=%i ctype=%u conntrack=%u\n",
+			       CTINFO2DIR(ctinfo), sch->type, oldsctpstate);
+			write_unlock_bh(&sctp_lock);
+			return -1;
+		}
+
+		/* If it is an INIT or an INIT ACK note down the vtag */
+		if (sch->type == SCTP_CID_INIT 
+			|| sch->type == SCTP_CID_INIT_ACK) {
+			sctp_inithdr_t _inithdr, *ih;
+
+			ih = skb_header_pointer(skb, offset + sizeof(sctp_chunkhdr_t),
+			                        sizeof(_inithdr), &_inithdr);
+			if (ih == NULL) {
+					write_unlock_bh(&sctp_lock);
+					return -1;
+			}
+			DEBUGP("Setting vtag %x for dir %d\n", 
+					ih->init_tag, !CTINFO2DIR(ctinfo));
+			conntrack->proto.sctp.vtag[!CTINFO2DIR(ctinfo)] = ih->init_tag;
+		}
+
+		conntrack->proto.sctp.state = newconntrack;
+		if (oldsctpstate != newconntrack)
+			nf_conntrack_event_cache(IPCT_PROTOINFO, skb);
+		write_unlock_bh(&sctp_lock);
+	}
+
+	nf_ct_refresh_acct(conntrack, ctinfo, skb, *sctp_timeouts[newconntrack]);
+
+	if (oldsctpstate == SCTP_CONNTRACK_COOKIE_ECHOED
+		&& CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY
+		&& newconntrack == SCTP_CONNTRACK_ESTABLISHED) {
+		DEBUGP("Setting assured bit\n");
+		set_bit(IPS_ASSURED_BIT, &conntrack->status);
+		nf_conntrack_event_cache(IPCT_STATUS, skb);
+	}
+
+	return NF_ACCEPT;
+}
+
+/* Called when a new connection for this protocol found. */
+static int sctp_new(struct nf_conn *conntrack, const struct sk_buff *skb,
+		    unsigned int dataoff)
+{
+	enum sctp_conntrack newconntrack;
+	sctp_sctphdr_t _sctph, *sh;
+	sctp_chunkhdr_t _sch, *sch;
+	u_int32_t offset, count;
+	char map[256 / sizeof (char)] = {0};
+
+	DEBUGP(__FUNCTION__);
+	DEBUGP("\n");
+
+	sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
+	if (sh == NULL)
+		return 0;
+
+	if (do_basic_checks(conntrack, skb, dataoff, map) != 0)
+		return 0;
+
+	/* If an OOTB packet has any of these chunks discard (Sec 8.4) */
+	if ((test_bit (SCTP_CID_ABORT, (void *)map))
+		|| (test_bit (SCTP_CID_SHUTDOWN_COMPLETE, (void *)map))
+		|| (test_bit (SCTP_CID_COOKIE_ACK, (void *)map))) {
+		return 0;
+	}
+
+	newconntrack = SCTP_CONNTRACK_MAX;
+	for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
+		/* Don't need lock here: this conntrack not in circulation yet */
+		newconntrack = new_state(IP_CT_DIR_ORIGINAL, 
+					 SCTP_CONNTRACK_NONE, sch->type);
+
+		/* Invalid: delete conntrack */
+		if (newconntrack == SCTP_CONNTRACK_MAX) {
+			DEBUGP("nf_conntrack_sctp: invalid new deleting.\n");
+			return 0;
+		}
+
+		/* Copy the vtag into the state info */
+		if (sch->type == SCTP_CID_INIT) {
+			if (sh->vtag == 0) {
+				sctp_inithdr_t _inithdr, *ih;
+
+				ih = skb_header_pointer(skb, offset + sizeof(sctp_chunkhdr_t),
+				                        sizeof(_inithdr), &_inithdr);
+				if (ih == NULL)
+					return 0;
+
+				DEBUGP("Setting vtag %x for new conn\n", 
+					ih->init_tag);
+
+				conntrack->proto.sctp.vtag[IP_CT_DIR_REPLY] = 
+								ih->init_tag;
+			} else {
+				/* Sec 8.5.1 (A) */
+				return 0;
+			}
+		}
+		/* If it is a shutdown ack OOTB packet, we expect a return
+		   shutdown complete, otherwise an ABORT Sec 8.4 (5) and (8) */
+		else {
+			DEBUGP("Setting vtag %x for new conn OOTB\n", 
+				sh->vtag);
+			conntrack->proto.sctp.vtag[IP_CT_DIR_REPLY] = sh->vtag;
+		}
+
+		conntrack->proto.sctp.state = newconntrack;
+	}
+
+	return 1;
+}
+
+struct nf_conntrack_protocol nf_conntrack_protocol_sctp4 = { 
+	.l3proto	 = PF_INET,
+	.proto 		 = IPPROTO_SCTP, 
+	.name 		 = "sctp",
+	.pkt_to_tuple 	 = sctp_pkt_to_tuple, 
+	.invert_tuple 	 = sctp_invert_tuple, 
+	.print_tuple 	 = sctp_print_tuple, 
+	.print_conntrack = sctp_print_conntrack,
+	.packet 	 = sctp_packet, 
+	.new 		 = sctp_new, 
+	.destroy 	 = NULL, 
+	.me 		 = THIS_MODULE 
+};
+
+struct nf_conntrack_protocol nf_conntrack_protocol_sctp6 = { 
+	.l3proto	 = PF_INET6,
+	.proto 		 = IPPROTO_SCTP, 
+	.name 		 = "sctp",
+	.pkt_to_tuple 	 = sctp_pkt_to_tuple, 
+	.invert_tuple 	 = sctp_invert_tuple, 
+	.print_tuple 	 = sctp_print_tuple, 
+	.print_conntrack = sctp_print_conntrack,
+	.packet 	 = sctp_packet, 
+	.new 		 = sctp_new, 
+	.destroy 	 = NULL, 
+	.me 		 = THIS_MODULE 
+};
+
+#ifdef CONFIG_SYSCTL
+static ctl_table nf_ct_sysctl_table[] = {
+	{
+		.ctl_name	= NET_NF_CONNTRACK_SCTP_TIMEOUT_CLOSED,
+		.procname	= "nf_conntrack_sctp_timeout_closed",
+		.data		= &nf_ct_sctp_timeout_closed,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec_jiffies,
+	},
+	{
+		.ctl_name	= NET_NF_CONNTRACK_SCTP_TIMEOUT_COOKIE_WAIT,
+		.procname	= "nf_conntrack_sctp_timeout_cookie_wait",
+		.data		= &nf_ct_sctp_timeout_cookie_wait,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec_jiffies,
+	},
+	{
+		.ctl_name	= NET_NF_CONNTRACK_SCTP_TIMEOUT_COOKIE_ECHOED,
+		.procname	= "nf_conntrack_sctp_timeout_cookie_echoed",
+		.data		= &nf_ct_sctp_timeout_cookie_echoed,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec_jiffies,
+	},
+	{
+		.ctl_name	= NET_NF_CONNTRACK_SCTP_TIMEOUT_ESTABLISHED,
+		.procname	= "nf_conntrack_sctp_timeout_established",
+		.data		= &nf_ct_sctp_timeout_established,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec_jiffies,
+	},
+	{
+		.ctl_name	= NET_NF_CONNTRACK_SCTP_TIMEOUT_SHUTDOWN_SENT,
+		.procname	= "nf_conntrack_sctp_timeout_shutdown_sent",
+		.data		= &nf_ct_sctp_timeout_shutdown_sent,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec_jiffies,
+	},
+	{
+		.ctl_name	= NET_NF_CONNTRACK_SCTP_TIMEOUT_SHUTDOWN_RECD,
+		.procname	= "nf_conntrack_sctp_timeout_shutdown_recd",
+		.data		= &nf_ct_sctp_timeout_shutdown_recd,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec_jiffies,
+	},
+	{
+		.ctl_name	= NET_NF_CONNTRACK_SCTP_TIMEOUT_SHUTDOWN_ACK_SENT,
+		.procname	= "nf_conntrack_sctp_timeout_shutdown_ack_sent",
+		.data		= &nf_ct_sctp_timeout_shutdown_ack_sent,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec_jiffies,
+	},
+	{ .ctl_name = 0 }
+};
+
+static ctl_table nf_ct_netfilter_table[] = {
+	{
+		.ctl_name	= NET_NETFILTER,
+		.procname	= "netfilter",
+		.mode		= 0555,
+		.child		= nf_ct_sysctl_table,
+	},
+	{ .ctl_name = 0 }
+};
+
+static ctl_table nf_ct_net_table[] = {
+	{
+		.ctl_name	= CTL_NET,
+		.procname	= "net",
+		.mode		= 0555, 
+		.child		= nf_ct_netfilter_table,
+	},
+	{ .ctl_name = 0 }
+};
+
+static struct ctl_table_header *nf_ct_sysctl_header;
+#endif
+
+int __init init(void)
+{
+	int ret;
+
+	ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_sctp4);
+	if (ret) {
+		printk("nf_conntrack_proto_sctp4: protocol register failed\n");
+		goto out;
+	}
+	ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_sctp6);
+	if (ret) {
+		printk("nf_conntrack_proto_sctp6: protocol register failed\n");
+		goto cleanup_sctp4;
+	}
+
+#ifdef CONFIG_SYSCTL
+	nf_ct_sysctl_header = register_sysctl_table(nf_ct_net_table, 0);
+	if (nf_ct_sysctl_header == NULL) {
+		printk("nf_conntrack_proto_sctp: can't register to sysctl.\n");
+		goto cleanup;
+	}
+#endif
+
+	return ret;
+
+#ifdef CONFIG_SYSCTL
+ cleanup:
+	nf_conntrack_protocol_unregister(&nf_conntrack_protocol_sctp6);
+#endif
+ cleanup_sctp4:
+	nf_conntrack_protocol_unregister(&nf_conntrack_protocol_sctp4);
+ out:
+	DEBUGP("SCTP conntrack module loading %s\n", 
+					ret ? "failed": "succeeded");
+	return ret;
+}
+
+void __exit fini(void)
+{
+	nf_conntrack_protocol_unregister(&nf_conntrack_protocol_sctp6);
+	nf_conntrack_protocol_unregister(&nf_conntrack_protocol_sctp4);
+#ifdef CONFIG_SYSCTL
+ 	unregister_sysctl_table(nf_ct_sysctl_header);
+#endif
+	DEBUGP("SCTP conntrack module unloaded\n");
+}
+
+module_init(init);
+module_exit(fini);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Kiran Kumar Immidi");
+MODULE_DESCRIPTION("Netfilter connection tracking protocol helper for SCTP");