1/*
2 *	xt_connmark - Netfilter module to operate on connection marks
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@medozas.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, see <http://www.gnu.org/licenses/>.
21 */
22
23#include <linux/module.h>
24#include <linux/skbuff.h>
25#include <net/netfilter/nf_conntrack.h>
26#include <net/netfilter/nf_conntrack_ecache.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 operations");
32MODULE_LICENSE("GPL");
33MODULE_ALIAS("ipt_CONNMARK");
34MODULE_ALIAS("ip6t_CONNMARK");
35MODULE_ALIAS("ipt_connmark");
36MODULE_ALIAS("ip6t_connmark");
37
38static unsigned int
39connmark_tg(struct sk_buff *skb, const struct xt_action_param *par)
40{
41	const struct xt_connmark_tginfo1 *info = par->targinfo;
42	enum ip_conntrack_info ctinfo;
43	struct nf_conn *ct;
44	u_int32_t newmark;
45
46	ct = nf_ct_get(skb, &ctinfo);
47	if (ct == NULL)
48		return XT_CONTINUE;
49
50	switch (info->mode) {
51	case XT_CONNMARK_SET:
52		newmark = (ct->mark & ~info->ctmask) ^ info->ctmark;
53		if (ct->mark != newmark) {
54			ct->mark = newmark;
55			nf_conntrack_event_cache(IPCT_MARK, ct);
56		}
57		break;
58	case XT_CONNMARK_SAVE:
59		newmark = (ct->mark & ~info->ctmask) ^
60		          (skb->mark & info->nfmask);
61		if (ct->mark != newmark) {
62			ct->mark = newmark;
63			nf_conntrack_event_cache(IPCT_MARK, ct);
64		}
65		break;
66	case XT_CONNMARK_RESTORE:
67		newmark = (skb->mark & ~info->nfmask) ^
68		          (ct->mark & info->ctmask);
69		skb->mark = newmark;
70		break;
71	}
72
73	return XT_CONTINUE;
74}
75
76static int connmark_tg_check(const struct xt_tgchk_param *par)
77{
78	int ret;
79
80	ret = nf_ct_l3proto_try_module_get(par->family);
81	if (ret < 0)
82		pr_info("cannot load conntrack support for proto=%u\n",
83			par->family);
84	return ret;
85}
86
87static void connmark_tg_destroy(const struct xt_tgdtor_param *par)
88{
89	nf_ct_l3proto_module_put(par->family);
90}
91
92static bool
93connmark_mt(const struct sk_buff *skb, struct xt_action_param *par)
94{
95	const struct xt_connmark_mtinfo1 *info = par->matchinfo;
96	enum ip_conntrack_info ctinfo;
97	const struct nf_conn *ct;
98
99	ct = nf_ct_get(skb, &ctinfo);
100	if (ct == NULL)
101		return false;
102
103	return ((ct->mark & info->mask) == info->mark) ^ info->invert;
104}
105
106static int connmark_mt_check(const struct xt_mtchk_param *par)
107{
108	int ret;
109
110	ret = nf_ct_l3proto_try_module_get(par->family);
111	if (ret < 0)
112		pr_info("cannot load conntrack support for proto=%u\n",
113			par->family);
114	return ret;
115}
116
117static void connmark_mt_destroy(const struct xt_mtdtor_param *par)
118{
119	nf_ct_l3proto_module_put(par->family);
120}
121
122static struct xt_target connmark_tg_reg __read_mostly = {
123	.name           = "CONNMARK",
124	.revision       = 1,
125	.family         = NFPROTO_UNSPEC,
126	.checkentry     = connmark_tg_check,
127	.target         = connmark_tg,
128	.targetsize     = sizeof(struct xt_connmark_tginfo1),
129	.destroy        = connmark_tg_destroy,
130	.me             = THIS_MODULE,
131};
132
133static struct xt_match connmark_mt_reg __read_mostly = {
134	.name           = "connmark",
135	.revision       = 1,
136	.family         = NFPROTO_UNSPEC,
137	.checkentry     = connmark_mt_check,
138	.match          = connmark_mt,
139	.matchsize      = sizeof(struct xt_connmark_mtinfo1),
140	.destroy        = connmark_mt_destroy,
141	.me             = THIS_MODULE,
142};
143
144static int __init connmark_mt_init(void)
145{
146	int ret;
147
148	ret = xt_register_target(&connmark_tg_reg);
149	if (ret < 0)
150		return ret;
151	ret = xt_register_match(&connmark_mt_reg);
152	if (ret < 0) {
153		xt_unregister_target(&connmark_tg_reg);
154		return ret;
155	}
156	return 0;
157}
158
159static void __exit connmark_mt_exit(void)
160{
161	xt_unregister_match(&connmark_mt_reg);
162	xt_unregister_target(&connmark_tg_reg);
163}
164
165module_init(connmark_mt_init);
166module_exit(connmark_mt_exit);
167