2005-08-13 22:56:26 +02:00
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/* Kernel module to match connection tracking byte counter.
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* GPL (C) 2002 Martin Devera (devik@cdi.cz).
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*
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* 2004-07-20 Harald Welte <laforge@netfilter.org>
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* - reimplemented to use per-connection accounting counters
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* - add functionality to match number of packets
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* - add functionality to match average packet size
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* - add support to match directions seperately
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*
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*/
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/netfilter_ipv4/ip_conntrack.h>
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#include <linux/netfilter_ipv4/ip_tables.h>
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#include <linux/netfilter_ipv4/ipt_connbytes.h>
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#include <asm/div64.h>
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#include <asm/bitops.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
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MODULE_DESCRIPTION("iptables match for matching number of pkts/bytes per connection");
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/* 64bit divisor, dividend and result. dynamic precision */
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2005-08-13 22:57:58 +02:00
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static u_int64_t div64_64(u_int64_t dividend, u_int64_t divisor)
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2005-08-13 22:56:26 +02:00
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{
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2005-08-13 22:57:58 +02:00
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u_int32_t d = divisor;
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2005-08-13 22:56:26 +02:00
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2005-08-13 22:57:58 +02:00
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if (divisor > 0xffffffffULL) {
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unsigned int shift = fls(divisor >> 32);
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2005-08-13 22:56:26 +02:00
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2005-08-13 22:57:58 +02:00
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d = divisor >> shift;
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dividend >>= shift;
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}
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2005-08-13 22:56:26 +02:00
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2005-08-13 22:57:58 +02:00
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do_div(dividend, d);
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return dividend;
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2005-08-13 22:56:26 +02:00
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}
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static int
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match(const struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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const void *matchinfo,
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int offset,
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int *hotdrop)
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{
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const struct ipt_connbytes_info *sinfo = matchinfo;
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enum ip_conntrack_info ctinfo;
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struct ip_conntrack *ct;
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u_int64_t what = 0; /* initialize to make gcc happy */
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if (!(ct = ip_conntrack_get((struct sk_buff *)skb, &ctinfo)))
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return 0; /* no match */
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switch (sinfo->what) {
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case IPT_CONNBYTES_WHAT_PKTS:
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switch (sinfo->direction) {
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case IPT_CONNBYTES_DIR_ORIGINAL:
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what = ct->counters[IP_CT_DIR_ORIGINAL].packets;
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break;
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case IPT_CONNBYTES_DIR_REPLY:
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what = ct->counters[IP_CT_DIR_REPLY].packets;
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break;
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case IPT_CONNBYTES_DIR_BOTH:
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what = ct->counters[IP_CT_DIR_ORIGINAL].packets;
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what += ct->counters[IP_CT_DIR_REPLY].packets;
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break;
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}
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break;
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case IPT_CONNBYTES_WHAT_BYTES:
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switch (sinfo->direction) {
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case IPT_CONNBYTES_DIR_ORIGINAL:
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what = ct->counters[IP_CT_DIR_ORIGINAL].bytes;
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break;
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case IPT_CONNBYTES_DIR_REPLY:
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what = ct->counters[IP_CT_DIR_REPLY].bytes;
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break;
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case IPT_CONNBYTES_DIR_BOTH:
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what = ct->counters[IP_CT_DIR_ORIGINAL].bytes;
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what += ct->counters[IP_CT_DIR_REPLY].bytes;
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break;
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}
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break;
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case IPT_CONNBYTES_WHAT_AVGPKT:
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switch (sinfo->direction) {
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case IPT_CONNBYTES_DIR_ORIGINAL:
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what = div64_64(ct->counters[IP_CT_DIR_ORIGINAL].bytes,
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ct->counters[IP_CT_DIR_ORIGINAL].packets);
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break;
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case IPT_CONNBYTES_DIR_REPLY:
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what = div64_64(ct->counters[IP_CT_DIR_REPLY].bytes,
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ct->counters[IP_CT_DIR_REPLY].packets);
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break;
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case IPT_CONNBYTES_DIR_BOTH:
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{
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u_int64_t bytes;
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u_int64_t pkts;
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bytes = ct->counters[IP_CT_DIR_ORIGINAL].bytes +
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ct->counters[IP_CT_DIR_REPLY].bytes;
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pkts = ct->counters[IP_CT_DIR_ORIGINAL].packets+
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ct->counters[IP_CT_DIR_REPLY].packets;
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/* FIXME_THEORETICAL: what to do if sum
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* overflows ? */
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what = div64_64(bytes, pkts);
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}
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break;
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}
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break;
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}
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if (sinfo->count.to)
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return (what <= sinfo->count.to && what >= sinfo->count.from);
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else
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return (what >= sinfo->count.from);
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}
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static int check(const char *tablename,
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const struct ipt_ip *ip,
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void *matchinfo,
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unsigned int matchsize,
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unsigned int hook_mask)
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{
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const struct ipt_connbytes_info *sinfo = matchinfo;
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if (matchsize != IPT_ALIGN(sizeof(struct ipt_connbytes_info)))
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return 0;
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if (sinfo->what != IPT_CONNBYTES_WHAT_PKTS &&
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sinfo->what != IPT_CONNBYTES_WHAT_BYTES &&
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sinfo->what != IPT_CONNBYTES_WHAT_AVGPKT)
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return 0;
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if (sinfo->direction != IPT_CONNBYTES_DIR_ORIGINAL &&
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sinfo->direction != IPT_CONNBYTES_DIR_REPLY &&
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sinfo->direction != IPT_CONNBYTES_DIR_BOTH)
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return 0;
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return 1;
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}
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static struct ipt_match state_match = {
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.name = "connbytes",
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.match = &match,
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.checkentry = &check,
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.me = THIS_MODULE
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};
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static int __init init(void)
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{
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return ipt_register_match(&state_match);
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}
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static void __exit fini(void)
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{
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ipt_unregister_match(&state_match);
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}
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module_init(init);
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module_exit(fini);
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