Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
[linux-2.6] / net / netfilter / xt_state.c
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
17 MODULE_LICENSE("GPL");
18 MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
19 MODULE_DESCRIPTION("ip[6]_tables connection tracking state match module");
20 MODULE_ALIAS("ipt_state");
21 MODULE_ALIAS("ip6t_state");
22
23 static bool
24 state_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
43 static bool
44 state_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
56 static void state_mt_destroy(const struct xt_match *match, void *matchinfo)
57 {
58         nf_ct_l3proto_module_put(match->family);
59 }
60
61 static 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
82 static int __init state_mt_init(void)
83 {
84         return xt_register_matches(state_mt_reg, ARRAY_SIZE(state_mt_reg));
85 }
86
87 static void __exit state_mt_exit(void)
88 {
89         xt_unregister_matches(state_mt_reg, ARRAY_SIZE(state_mt_reg));
90 }
91
92 module_init(state_mt_init);
93 module_exit(state_mt_exit);