Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* Kernel module to match connection tracking information. */ |
2 | ||
3 | /* (C) 1999-2001 Paul `Rusty' Russell | |
4 | * (C) 2002-2004 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 <linux/netfilter_ipv4/ip_conntrack.h> | |
14 | #include <linux/netfilter_ipv4/ip_tables.h> | |
15 | #include <linux/netfilter_ipv4/ipt_state.h> | |
16 | ||
17 | MODULE_LICENSE("GPL"); | |
18 | MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>"); | |
19 | MODULE_DESCRIPTION("iptables connection tracking state match module"); | |
20 | ||
21 | static int | |
22 | match(const struct sk_buff *skb, | |
23 | const struct net_device *in, | |
24 | const struct net_device *out, | |
25 | const void *matchinfo, | |
26 | int offset, | |
27 | int *hotdrop) | |
28 | { | |
29 | const struct ipt_state_info *sinfo = matchinfo; | |
30 | enum ip_conntrack_info ctinfo; | |
31 | unsigned int statebit; | |
32 | ||
33 | if (skb->nfct == &ip_conntrack_untracked.ct_general) | |
34 | statebit = IPT_STATE_UNTRACKED; | |
35 | else if (!ip_conntrack_get(skb, &ctinfo)) | |
36 | statebit = IPT_STATE_INVALID; | |
37 | else | |
38 | statebit = IPT_STATE_BIT(ctinfo); | |
39 | ||
40 | return (sinfo->statemask & statebit); | |
41 | } | |
42 | ||
43 | static int check(const char *tablename, | |
44 | const struct ipt_ip *ip, | |
45 | void *matchinfo, | |
46 | unsigned int matchsize, | |
47 | unsigned int hook_mask) | |
48 | { | |
49 | if (matchsize != IPT_ALIGN(sizeof(struct ipt_state_info))) | |
50 | return 0; | |
51 | ||
52 | return 1; | |
53 | } | |
54 | ||
55 | static struct ipt_match state_match = { | |
56 | .name = "state", | |
57 | .match = &match, | |
58 | .checkentry = &check, | |
59 | .me = THIS_MODULE, | |
60 | }; | |
61 | ||
62 | static int __init init(void) | |
63 | { | |
64 | need_ip_conntrack(); | |
65 | return ipt_register_match(&state_match); | |
66 | } | |
67 | ||
68 | static void __exit fini(void) | |
69 | { | |
70 | ipt_unregister_match(&state_match); | |
71 | } | |
72 | ||
73 | module_init(init); | |
74 | module_exit(fini); |