tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/* Kernel module to match connection tracking information. */
2
3/* (C) 1999-2001 Paul `Rusty' Russell
4 * (C) 2002-2005 Netfilter Core Team <coreteam@netfilter.org>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include <linux/module.h>
12#include <linux/skbuff.h>
13#include <net/netfilter/nf_conntrack.h>
14#include <linux/netfilter/x_tables.h>
15#include <linux/netfilter/xt_state.h>
16
17MODULE_LICENSE("GPL");
18MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
19MODULE_DESCRIPTION("ip[6]_tables connection tracking state match module");
20MODULE_ALIAS("ipt_state");
21MODULE_ALIAS("ip6t_state");
22
23static bool
24state_mt(const struct sk_buff *skb, const struct net_device *in,
25 const struct net_device *out, const struct xt_match *match,
26 const void *matchinfo, int offset, unsigned int protoff,
27 bool *hotdrop)
28{
29 const struct xt_state_info *sinfo = matchinfo;
30 enum ip_conntrack_info ctinfo;
31 unsigned int statebit;
32
33 if (nf_ct_is_untracked(skb))
34 statebit = XT_STATE_UNTRACKED;
35 else if (!nf_ct_get(skb, &ctinfo))
36 statebit = XT_STATE_INVALID;
37 else
38 statebit = XT_STATE_BIT(ctinfo);
39
40 return (sinfo->statemask & statebit);
41}
42
43static bool
44state_mt_check(const char *tablename, const void *inf,
45 const struct xt_match *match, void *matchinfo,
46 unsigned int hook_mask)
47{
48 if (nf_ct_l3proto_try_module_get(match->family) < 0) {
49 printk(KERN_WARNING "can't load conntrack support for "
50 "proto=%u\n", match->family);
51 return false;
52 }
53 return true;
54}
55
56static void state_mt_destroy(const struct xt_match *match, void *matchinfo)
57{
58 nf_ct_l3proto_module_put(match->family);
59}
60
61static struct xt_match state_mt_reg[] __read_mostly = {
62 {
63 .name = "state",
64 .family = AF_INET,
65 .checkentry = state_mt_check,
66 .match = state_mt,
67 .destroy = state_mt_destroy,
68 .matchsize = sizeof(struct xt_state_info),
69 .me = THIS_MODULE,
70 },
71 {
72 .name = "state",
73 .family = AF_INET6,
74 .checkentry = state_mt_check,
75 .match = state_mt,
76 .destroy = state_mt_destroy,
77 .matchsize = sizeof(struct xt_state_info),
78 .me = THIS_MODULE,
79 },
80};
81
82static int __init state_mt_init(void)
83{
84 return xt_register_matches(state_mt_reg, ARRAY_SIZE(state_mt_reg));
85}
86
87static void __exit state_mt_exit(void)
88{
89 xt_unregister_matches(state_mt_reg, ARRAY_SIZE(state_mt_reg));
90}
91
92module_init(state_mt_init);
93module_exit(state_mt_exit);