[NETFILTER]: Remove IPv4 only connection tracking/NAT
[linux-2.6.git] / 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 int
24 match(const struct sk_buff *skb,
25       const struct net_device *in,
26       const struct net_device *out,
27       const struct xt_match *match,
28       const void *matchinfo,
29       int offset,
30       unsigned int protoff,
31       int *hotdrop)
32 {
33         const struct xt_state_info *sinfo = matchinfo;
34         enum ip_conntrack_info ctinfo;
35         unsigned int statebit;
36
37         if (nf_ct_is_untracked(skb))
38                 statebit = XT_STATE_UNTRACKED;
39         else if (!nf_ct_get(skb, &ctinfo))
40                 statebit = XT_STATE_INVALID;
41         else
42                 statebit = XT_STATE_BIT(ctinfo);
43
44         return (sinfo->statemask & statebit);
45 }
46
47 static int check(const char *tablename,
48                  const void *inf,
49                  const struct xt_match *match,
50                  void *matchinfo,
51                  unsigned int hook_mask)
52 {
53         if (nf_ct_l3proto_try_module_get(match->family) < 0) {
54                 printk(KERN_WARNING "can't load conntrack support for "
55                                     "proto=%d\n", match->family);
56                 return 0;
57         }
58         return 1;
59 }
60
61 static void
62 destroy(const struct xt_match *match, void *matchinfo)
63 {
64         nf_ct_l3proto_module_put(match->family);
65 }
66
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         },
86 };
87
88 static int __init xt_state_init(void)
89 {
90         return xt_register_matches(xt_state_match, ARRAY_SIZE(xt_state_match));
91 }
92
93 static void __exit xt_state_fini(void)
94 {
95         xt_unregister_matches(xt_state_match, ARRAY_SIZE(xt_state_match));
96 }
97
98 module_init(xt_state_init);
99 module_exit(xt_state_fini);