netfilter: xtables: change xt_match.checkentry return type
[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 bool
24 state_mt(const struct sk_buff *skb, const struct xt_match_param *par)
25 {
26         const struct xt_state_info *sinfo = par->matchinfo;
27         enum ip_conntrack_info ctinfo;
28         unsigned int statebit;
29
30         if (nf_ct_is_untracked(skb))
31                 statebit = XT_STATE_UNTRACKED;
32         else if (!nf_ct_get(skb, &ctinfo))
33                 statebit = XT_STATE_INVALID;
34         else
35                 statebit = XT_STATE_BIT(ctinfo);
36
37         return (sinfo->statemask & statebit);
38 }
39
40 static int state_mt_check(const struct xt_mtchk_param *par)
41 {
42         if (nf_ct_l3proto_try_module_get(par->family) < 0) {
43                 pr_info("cannot load conntrack support for proto=%u\n",
44                         par->family);
45                 return false;
46         }
47         return true;
48 }
49
50 static void state_mt_destroy(const struct xt_mtdtor_param *par)
51 {
52         nf_ct_l3proto_module_put(par->family);
53 }
54
55 static struct xt_match state_mt_reg[] __read_mostly = {
56         {
57                 .name           = "state",
58                 .family         = NFPROTO_IPV4,
59                 .checkentry     = state_mt_check,
60                 .match          = state_mt,
61                 .destroy        = state_mt_destroy,
62                 .matchsize      = sizeof(struct xt_state_info),
63                 .me             = THIS_MODULE,
64         },
65         {
66                 .name           = "state",
67                 .family         = NFPROTO_IPV6,
68                 .checkentry     = state_mt_check,
69                 .match          = state_mt,
70                 .destroy        = state_mt_destroy,
71                 .matchsize      = sizeof(struct xt_state_info),
72                 .me             = THIS_MODULE,
73         },
74 };
75
76 static int __init state_mt_init(void)
77 {
78         return xt_register_matches(state_mt_reg, ARRAY_SIZE(state_mt_reg));
79 }
80
81 static void __exit state_mt_exit(void)
82 {
83         xt_unregister_matches(state_mt_reg, ARRAY_SIZE(state_mt_reg));
84 }
85
86 module_init(state_mt_init);
87 module_exit(state_mt_exit);