Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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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, struct xt_action_param *par)
25{
26 const struct xt_state_info *sinfo = par->matchinfo;
27 enum ip_conntrack_info ctinfo;
28 unsigned int statebit;
29 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
30
31 if (ct)
32 statebit = XT_STATE_BIT(ctinfo);
33 else if (ctinfo == IP_CT_UNTRACKED)
34 statebit = XT_STATE_UNTRACKED;
35 else
36 statebit = XT_STATE_INVALID;
37
38 return (sinfo->statemask & statebit);
39}
40
41static int state_mt_check(const struct xt_mtchk_param *par)
42{
43 int ret;
44
45 ret = nf_ct_netns_get(par->net, par->family);
46 if (ret < 0)
47 pr_info_ratelimited("cannot load conntrack support for proto=%u\n",
48 par->family);
49 return ret;
50}
51
52static void state_mt_destroy(const struct xt_mtdtor_param *par)
53{
54 nf_ct_netns_put(par->net, par->family);
55}
56
57static struct xt_match state_mt_reg __read_mostly = {
58 .name = "state",
59 .family = NFPROTO_UNSPEC,
60 .checkentry = state_mt_check,
61 .match = state_mt,
62 .destroy = state_mt_destroy,
63 .matchsize = sizeof(struct xt_state_info),
64 .me = THIS_MODULE,
65};
66
67static int __init state_mt_init(void)
68{
69 return xt_register_match(&state_mt_reg);
70}
71
72static void __exit state_mt_exit(void)
73{
74 xt_unregister_match(&state_mt_reg);
75}
76
77module_init(state_mt_init);
78module_exit(state_mt_exit);