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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, | |
b9f78f9f PNA |
51 | unsigned int hook_mask) |
52 | { | |
b9f78f9f | 53 | if (nf_ct_l3proto_try_module_get(match->family) < 0) { |
fe0b9294 | 54 | printk(KERN_WARNING "can't load conntrack support for " |
b9f78f9f PNA |
55 | "proto=%d\n", match->family); |
56 | return 0; | |
57 | } | |
b9f78f9f PNA |
58 | return 1; |
59 | } | |
60 | ||
61 | static void | |
efa74165 | 62 | destroy(const struct xt_match *match, void *matchinfo) |
b9f78f9f | 63 | { |
b9f78f9f | 64 | nf_ct_l3proto_module_put(match->family); |
b9f78f9f PNA |
65 | } |
66 | ||
4470bbc7 PM |
67 | static struct xt_match xt_state_match[] = { |
68 | { | |
69 | .name = "state", | |
70 | .family = AF_INET, | |
71 | .checkentry = check, | |
72 | .match = match, | |
73 | .destroy = destroy, | |
74 | .matchsize = sizeof(struct xt_state_info), | |
75 | .me = THIS_MODULE, | |
76 | }, | |
77 | { | |
78 | .name = "state", | |
79 | .family = AF_INET6, | |
80 | .checkentry = check, | |
81 | .match = match, | |
82 | .destroy = destroy, | |
83 | .matchsize = sizeof(struct xt_state_info), | |
84 | .me = THIS_MODULE, | |
85 | }, | |
1da177e4 LT |
86 | }; |
87 | ||
65b4b4e8 | 88 | static int __init xt_state_init(void) |
1da177e4 | 89 | { |
4470bbc7 | 90 | return xt_register_matches(xt_state_match, ARRAY_SIZE(xt_state_match)); |
1da177e4 LT |
91 | } |
92 | ||
65b4b4e8 | 93 | static void __exit xt_state_fini(void) |
1da177e4 | 94 | { |
4470bbc7 | 95 | xt_unregister_matches(xt_state_match, ARRAY_SIZE(xt_state_match)); |
1da177e4 LT |
96 | } |
97 | ||
65b4b4e8 AM |
98 | module_init(xt_state_init); |
99 | module_exit(xt_state_fini); |