166 lines
4.1 KiB
C
166 lines
4.1 KiB
C
/* 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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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter/xt_connbytes.h>
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#include <net/netfilter/nf_conntrack.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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MODULE_ALIAS("ipt_connbytes");
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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 struct xt_match *match,
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const void *matchinfo,
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int offset,
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unsigned int protoff,
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int *hotdrop)
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{
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const struct xt_connbytes_info *sinfo = matchinfo;
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struct nf_conn *ct;
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enum ip_conntrack_info ctinfo;
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u_int64_t what = 0; /* initialize to make gcc happy */
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u_int64_t bytes = 0;
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u_int64_t pkts = 0;
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const struct ip_conntrack_counter *counters;
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ct = nf_ct_get(skb, &ctinfo);
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if (!ct)
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return 0;
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counters = ct->counters;
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switch (sinfo->what) {
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case XT_CONNBYTES_PKTS:
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switch (sinfo->direction) {
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case XT_CONNBYTES_DIR_ORIGINAL:
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what = counters[IP_CT_DIR_ORIGINAL].packets;
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break;
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case XT_CONNBYTES_DIR_REPLY:
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what = counters[IP_CT_DIR_REPLY].packets;
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break;
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case XT_CONNBYTES_DIR_BOTH:
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what = counters[IP_CT_DIR_ORIGINAL].packets;
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what += 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 XT_CONNBYTES_BYTES:
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switch (sinfo->direction) {
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case XT_CONNBYTES_DIR_ORIGINAL:
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what = counters[IP_CT_DIR_ORIGINAL].bytes;
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break;
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case XT_CONNBYTES_DIR_REPLY:
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what = counters[IP_CT_DIR_REPLY].bytes;
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break;
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case XT_CONNBYTES_DIR_BOTH:
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what = counters[IP_CT_DIR_ORIGINAL].bytes;
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what += 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 XT_CONNBYTES_AVGPKT:
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switch (sinfo->direction) {
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case XT_CONNBYTES_DIR_ORIGINAL:
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bytes = counters[IP_CT_DIR_ORIGINAL].bytes;
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pkts = counters[IP_CT_DIR_ORIGINAL].packets;
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break;
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case XT_CONNBYTES_DIR_REPLY:
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bytes = counters[IP_CT_DIR_REPLY].bytes;
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pkts = counters[IP_CT_DIR_REPLY].packets;
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break;
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case XT_CONNBYTES_DIR_BOTH:
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bytes = counters[IP_CT_DIR_ORIGINAL].bytes +
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counters[IP_CT_DIR_REPLY].bytes;
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pkts = counters[IP_CT_DIR_ORIGINAL].packets +
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counters[IP_CT_DIR_REPLY].packets;
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break;
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}
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if (pkts != 0)
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what = div64_64(bytes, pkts);
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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 void *ip,
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const struct xt_match *match,
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void *matchinfo,
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unsigned int hook_mask)
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{
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const struct xt_connbytes_info *sinfo = matchinfo;
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if (sinfo->what != XT_CONNBYTES_PKTS &&
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sinfo->what != XT_CONNBYTES_BYTES &&
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sinfo->what != XT_CONNBYTES_AVGPKT)
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return 0;
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if (sinfo->direction != XT_CONNBYTES_DIR_ORIGINAL &&
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sinfo->direction != XT_CONNBYTES_DIR_REPLY &&
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sinfo->direction != XT_CONNBYTES_DIR_BOTH)
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return 0;
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if (nf_ct_l3proto_try_module_get(match->family) < 0) {
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printk(KERN_WARNING "can't load conntrack support for "
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"proto=%d\n", match->family);
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return 0;
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}
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return 1;
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}
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static void
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destroy(const struct xt_match *match, void *matchinfo)
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{
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nf_ct_l3proto_module_put(match->family);
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}
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static struct xt_match xt_connbytes_match[] = {
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{
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.name = "connbytes",
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.family = AF_INET,
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.checkentry = check,
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.match = match,
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.destroy = destroy,
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.matchsize = sizeof(struct xt_connbytes_info),
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.me = THIS_MODULE
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},
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{
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.name = "connbytes",
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.family = AF_INET6,
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.checkentry = check,
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.match = match,
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.destroy = destroy,
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.matchsize = sizeof(struct xt_connbytes_info),
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.me = THIS_MODULE
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},
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};
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static int __init xt_connbytes_init(void)
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{
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return xt_register_matches(xt_connbytes_match,
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ARRAY_SIZE(xt_connbytes_match));
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}
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static void __exit xt_connbytes_fini(void)
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{
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xt_unregister_matches(xt_connbytes_match,
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ARRAY_SIZE(xt_connbytes_match));
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}
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module_init(xt_connbytes_init);
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module_exit(xt_connbytes_fini);
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