diff options
Diffstat (limited to 'net/netfilter/xt_connbytes.c')
| -rw-r--r-- | net/netfilter/xt_connbytes.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/net/netfilter/xt_connbytes.c b/net/netfilter/xt_connbytes.c new file mode 100644 index 0000000000000..150d2a4b0f710 --- /dev/null +++ b/net/netfilter/xt_connbytes.c @@ -0,0 +1,180 @@ +/* Kernel module to match connection tracking byte counter. + * GPL (C) 2002 Martin Devera (devik@cdi.cz). + * + * 2004-07-20 Harald Welte <laforge@netfilter.org> + * - reimplemented to use per-connection accounting counters + * - add functionality to match number of packets + * - add functionality to match average packet size + * - add support to match directions seperately + * 2005-10-16 Harald Welte <laforge@netfilter.org> + * - Port to x_tables + * + */ +#include <linux/module.h> +#include <linux/skbuff.h> +#include <net/netfilter/nf_conntrack_compat.h> +#include <linux/netfilter/x_tables.h> +#include <linux/netfilter/xt_connbytes.h> + +#include <asm/div64.h> +#include <asm/bitops.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); +MODULE_DESCRIPTION("iptables match for matching number of pkts/bytes per connection"); +MODULE_ALIAS("ipt_connbytes"); + +/* 64bit divisor, dividend and result. dynamic precision */ +static u_int64_t div64_64(u_int64_t dividend, u_int64_t divisor) +{ + u_int32_t d = divisor; + + if (divisor > 0xffffffffULL) { + unsigned int shift = fls(divisor >> 32); + + d = divisor >> shift; + dividend >>= shift; + } + + do_div(dividend, d); + return dividend; +} + +static int +match(const struct sk_buff *skb, + const struct net_device *in, + const struct net_device *out, + const void *matchinfo, + int offset, + unsigned int protoff, + int *hotdrop) +{ + const struct xt_connbytes_info *sinfo = matchinfo; + u_int64_t what = 0; /* initialize to make gcc happy */ + const struct ip_conntrack_counter *counters; + + if (!(counters = nf_ct_get_counters(skb))) + return 0; /* no match */ + + switch (sinfo->what) { + case XT_CONNBYTES_PKTS: + switch (sinfo->direction) { + case XT_CONNBYTES_DIR_ORIGINAL: + what = counters[IP_CT_DIR_ORIGINAL].packets; + break; + case XT_CONNBYTES_DIR_REPLY: + what = counters[IP_CT_DIR_REPLY].packets; + break; + case XT_CONNBYTES_DIR_BOTH: + what = counters[IP_CT_DIR_ORIGINAL].packets; + what += counters[IP_CT_DIR_REPLY].packets; + break; + } + break; + case XT_CONNBYTES_BYTES: + switch (sinfo->direction) { + case XT_CONNBYTES_DIR_ORIGINAL: + what = counters[IP_CT_DIR_ORIGINAL].bytes; + break; + case XT_CONNBYTES_DIR_REPLY: + what = counters[IP_CT_DIR_REPLY].bytes; + break; + case XT_CONNBYTES_DIR_BOTH: + what = counters[IP_CT_DIR_ORIGINAL].bytes; + what += counters[IP_CT_DIR_REPLY].bytes; + break; + } + break; + case XT_CONNBYTES_AVGPKT: + switch (sinfo->direction) { + case XT_CONNBYTES_DIR_ORIGINAL: + what = div64_64(counters[IP_CT_DIR_ORIGINAL].bytes, + counters[IP_CT_DIR_ORIGINAL].packets); + break; + case XT_CONNBYTES_DIR_REPLY: + what = div64_64(counters[IP_CT_DIR_REPLY].bytes, + counters[IP_CT_DIR_REPLY].packets); + break; + case XT_CONNBYTES_DIR_BOTH: + { + u_int64_t bytes; + u_int64_t pkts; + bytes = counters[IP_CT_DIR_ORIGINAL].bytes + + counters[IP_CT_DIR_REPLY].bytes; + pkts = counters[IP_CT_DIR_ORIGINAL].packets+ + counters[IP_CT_DIR_REPLY].packets; + + /* FIXME_THEORETICAL: what to do if sum + * overflows ? */ + + what = div64_64(bytes, pkts); + } + break; + } + break; + } + + if (sinfo->count.to) + return (what <= sinfo->count.to && what >= sinfo->count.from); + else + return (what >= sinfo->count.from); +} + +static int check(const char *tablename, + const void *ip, + void *matchinfo, + unsigned int matchsize, + unsigned int hook_mask) +{ + const struct xt_connbytes_info *sinfo = matchinfo; + + if (matchsize != XT_ALIGN(sizeof(struct xt_connbytes_info))) + return 0; + + if (sinfo->what != XT_CONNBYTES_PKTS && + sinfo->what != XT_CONNBYTES_BYTES && + sinfo->what != XT_CONNBYTES_AVGPKT) + return 0; + + if (sinfo->direction != XT_CONNBYTES_DIR_ORIGINAL && + sinfo->direction != XT_CONNBYTES_DIR_REPLY && + sinfo->direction != XT_CONNBYTES_DIR_BOTH) + return 0; + + return 1; +} + +static struct xt_match connbytes_match = { + .name = "connbytes", + .match = &match, + .checkentry = &check, + .me = THIS_MODULE +}; +static struct xt_match connbytes6_match = { + .name = "connbytes", + .match = &match, + .checkentry = &check, + .me = THIS_MODULE +}; + +static int __init init(void) +{ + int ret; + ret = xt_register_match(AF_INET, &connbytes_match); + if (ret) + return ret; + + ret = xt_register_match(AF_INET6, &connbytes6_match); + if (ret) + xt_unregister_match(AF_INET, &connbytes_match); + return ret; +} + +static void __exit fini(void) +{ + xt_unregister_match(AF_INET, &connbytes_match); + xt_unregister_match(AF_INET6, &connbytes6_match); +} + +module_init(init); +module_exit(fini); |