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1da177e4 LT |
1 | /* Kernel module to match connection tracking information. */ |
2 | ||
3 | /* (C) 1999-2001 Paul `Rusty' Russell | |
2e4e6a17 | 4 | * (C) 2002-2005 Netfilter Core Team <coreteam@netfilter.org> |
1da177e4 LT |
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> | |
9fb9cbb1 | 13 | #include <net/netfilter/nf_conntrack_compat.h> |
2e4e6a17 HW |
14 | #include <linux/netfilter/x_tables.h> |
15 | #include <linux/netfilter/xt_state.h> | |
1da177e4 LT |
16 | |
17 | MODULE_LICENSE("GPL"); | |
18 | MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>"); | |
2e4e6a17 HW |
19 | MODULE_DESCRIPTION("ip[6]_tables connection tracking state match module"); |
20 | MODULE_ALIAS("ipt_state"); | |
21 | MODULE_ALIAS("ip6t_state"); | |
1da177e4 LT |
22 | |
23 | static int | |
24 | match(const struct sk_buff *skb, | |
25 | const struct net_device *in, | |
26 | const struct net_device *out, | |
c4986734 | 27 | const struct xt_match *match, |
1da177e4 LT |
28 | const void *matchinfo, |
29 | int offset, | |
2e4e6a17 | 30 | unsigned int protoff, |
1da177e4 LT |
31 | int *hotdrop) |
32 | { | |
2e4e6a17 | 33 | const struct xt_state_info *sinfo = matchinfo; |
1da177e4 LT |
34 | enum ip_conntrack_info ctinfo; |
35 | unsigned int statebit; | |
36 | ||
9fb9cbb1 | 37 | if (nf_ct_is_untracked(skb)) |
2e4e6a17 | 38 | statebit = XT_STATE_UNTRACKED; |
9fb9cbb1 | 39 | else if (!nf_ct_get_ctinfo(skb, &ctinfo)) |
2e4e6a17 | 40 | statebit = XT_STATE_INVALID; |
1da177e4 | 41 | else |
2e4e6a17 | 42 | statebit = XT_STATE_BIT(ctinfo); |
1da177e4 LT |
43 | |
44 | return (sinfo->statemask & statebit); | |
45 | } | |
46 | ||
b9f78f9f PNA |
47 | static int check(const char *tablename, |
48 | const void *inf, | |
49 | const struct xt_match *match, | |
50 | void *matchinfo, | |
51 | unsigned int matchsize, | |
52 | unsigned int hook_mask) | |
53 | { | |
54 | #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) | |
55 | if (nf_ct_l3proto_try_module_get(match->family) < 0) { | |
56 | printk(KERN_WARNING "can't load nf_conntrack support for " | |
57 | "proto=%d\n", match->family); | |
58 | return 0; | |
59 | } | |
60 | #endif | |
61 | return 1; | |
62 | } | |
63 | ||
64 | static void | |
65 | destroy(const struct xt_match *match, void *matchinfo, unsigned int matchsize) | |
66 | { | |
67 | #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) | |
68 | nf_ct_l3proto_module_put(match->family); | |
69 | #endif | |
70 | } | |
71 | ||
2e4e6a17 HW |
72 | static struct xt_match state_match = { |
73 | .name = "state", | |
5d04bff0 | 74 | .match = match, |
b9f78f9f PNA |
75 | .checkentry = check, |
76 | .destroy = destroy, | |
5d04bff0 | 77 | .matchsize = sizeof(struct xt_state_info), |
a45049c5 | 78 | .family = AF_INET, |
2e4e6a17 HW |
79 | .me = THIS_MODULE, |
80 | }; | |
81 | ||
82 | static struct xt_match state6_match = { | |
1da177e4 | 83 | .name = "state", |
5d04bff0 | 84 | .match = match, |
b9f78f9f PNA |
85 | .checkentry = check, |
86 | .destroy = destroy, | |
5d04bff0 | 87 | .matchsize = sizeof(struct xt_state_info), |
a45049c5 | 88 | .family = AF_INET6, |
1da177e4 LT |
89 | .me = THIS_MODULE, |
90 | }; | |
91 | ||
92 | static int __init init(void) | |
93 | { | |
2e4e6a17 HW |
94 | int ret; |
95 | ||
96 | need_conntrack(); | |
97 | ||
a45049c5 | 98 | ret = xt_register_match(&state_match); |
2e4e6a17 HW |
99 | if (ret < 0) |
100 | return ret; | |
101 | ||
a45049c5 | 102 | ret = xt_register_match(&state6_match); |
2e4e6a17 | 103 | if (ret < 0) |
a45049c5 | 104 | xt_unregister_match(&state_match); |
2e4e6a17 HW |
105 | |
106 | return ret; | |
1da177e4 LT |
107 | } |
108 | ||
109 | static void __exit fini(void) | |
110 | { | |
a45049c5 PNA |
111 | xt_unregister_match(&state_match); |
112 | xt_unregister_match(&state6_match); | |
1da177e4 LT |
113 | } |
114 | ||
115 | module_init(init); | |
116 | module_exit(fini); |