/net/netfilter/xt_connmark.c

 1/*
 2 *	xt_connmark - Netfilter module to match connection mark values
 3 *
 4 *	Copyright (C) 2002,2004 MARA Systems AB <http://www.marasystems.com>
 5 *	by Henrik Nordstrom <hno@marasystems.com>
 6 *	Copyright © CC Computer Consultants GmbH, 2007 - 2008
 7 *	Jan Engelhardt <jengelh@computergmbh.de>
 8 *
 9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
22 */
23
24#include <linux/module.h>
25#include <linux/skbuff.h>
26#include <net/netfilter/nf_conntrack.h>
27#include <linux/netfilter/x_tables.h>
28#include <linux/netfilter/xt_connmark.h>
29
30MODULE_AUTHOR("Henrik Nordstrom <hno@marasystems.com>");
31MODULE_DESCRIPTION("Xtables: connection mark match");
32MODULE_LICENSE("GPL");
33MODULE_ALIAS("ipt_connmark");
34MODULE_ALIAS("ip6t_connmark");
35
36static bool
37connmark_mt(const struct sk_buff *skb, const struct xt_match_param *par)
38{
39	const struct xt_connmark_mtinfo1 *info = par->matchinfo;
40	enum ip_conntrack_info ctinfo;
41	const struct nf_conn *ct;
42
43	ct = nf_ct_get(skb, &ctinfo);
44	if (ct == NULL)
45		return false;
46
47	return ((ct->mark & info->mask) == info->mark) ^ info->invert;
48}
49
50static bool connmark_mt_check(const struct xt_mtchk_param *par)
51{
52	if (nf_ct_l3proto_try_module_get(par->family) < 0) {
53		printk(KERN_WARNING "cannot load conntrack support for "
54		       "proto=%u\n", par->family);
55		return false;
56	}
57	return true;
58}
59
60static void connmark_mt_destroy(const struct xt_mtdtor_param *par)
61{
62	nf_ct_l3proto_module_put(par->family);
63}
64
65static struct xt_match connmark_mt_reg __read_mostly = {
66	.name           = "connmark",
67	.revision       = 1,
68	.family         = NFPROTO_UNSPEC,
69	.checkentry     = connmark_mt_check,
70	.match          = connmark_mt,
71	.matchsize      = sizeof(struct xt_connmark_mtinfo1),
72	.destroy        = connmark_mt_destroy,
73	.me             = THIS_MODULE,
74};
75
76static int __init connmark_mt_init(void)
77{
78	return xt_register_match(&connmark_mt_reg);
79}
80
81static void __exit connmark_mt_exit(void)
82{
83	xt_unregister_match(&connmark_mt_reg);
84}
85
86module_init(connmark_mt_init);
87module_exit(connmark_mt_exit);