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Jan Engelhardt0dc8c762008-01-14 23:38:34 -08001/*
2 * xt_CONNMARK - Netfilter module to modify the connection mark values
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
Jan Engelhardt0dc8c762008-01-14 23:38:34 -08004 * 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>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 *
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#include <linux/module.h>
24#include <linux/skbuff.h>
25#include <linux/ip.h>
26#include <net/checksum.h>
27
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +020028MODULE_AUTHOR("Henrik Nordstrom <hno@marasystems.com>");
Jan Engelhardt2ae15b62008-01-14 23:42:28 -080029MODULE_DESCRIPTION("Xtables: connection mark modification");
Linus Torvalds1da177e2005-04-16 15:20:36 -070030MODULE_LICENSE("GPL");
Harald Welte2e4e6a12006-01-12 13:30:04 -080031MODULE_ALIAS("ipt_CONNMARK");
Jan Engelhardt73aaf932007-10-11 14:36:40 -070032MODULE_ALIAS("ip6t_CONNMARK");
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
Harald Welte2e4e6a12006-01-12 13:30:04 -080034#include <linux/netfilter/x_tables.h>
35#include <linux/netfilter/xt_CONNMARK.h>
Martin Josefssonf6180122006-11-29 02:35:01 +010036#include <net/netfilter/nf_conntrack_ecache.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
38static unsigned int
Jan Engelhardt7eb35582008-10-08 11:35:19 +020039connmark_tg(struct sk_buff *skb, const struct xt_target_param *par)
Jan Engelhardt0dc8c762008-01-14 23:38:34 -080040{
Jan Engelhardt7eb35582008-10-08 11:35:19 +020041 const struct xt_connmark_tginfo1 *info = par->targinfo;
Jan Engelhardt0dc8c762008-01-14 23:38:34 -080042 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;
Alexey Dobriyana71996f2008-10-08 11:35:07 +020055 nf_conntrack_event_cache(IPCT_MARK, ct);
Jan Engelhardt0dc8c762008-01-14 23:38:34 -080056 }
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;
Alexey Dobriyana71996f2008-10-08 11:35:07 +020063 nf_conntrack_event_cache(IPCT_MARK, ct);
Jan Engelhardt0dc8c762008-01-14 23:38:34 -080064 }
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
Jan Engelhardtaf5d6dc2008-10-08 11:35:19 +020076static bool connmark_tg_check(const struct xt_tgchk_param *par)
Jan Engelhardt0dc8c762008-01-14 23:38:34 -080077{
Jan Engelhardt92f3b2b2008-10-08 11:35:20 +020078 if (nf_ct_l3proto_try_module_get(par->family) < 0) {
Jan Engelhardt0dc8c762008-01-14 23:38:34 -080079 printk(KERN_WARNING "cannot load conntrack support for "
Jan Engelhardt92f3b2b2008-10-08 11:35:20 +020080 "proto=%u\n", par->family);
Jan Engelhardt0dc8c762008-01-14 23:38:34 -080081 return false;
82 }
83 return true;
84}
85
Jan Engelhardta2df1642008-10-08 11:35:19 +020086static void connmark_tg_destroy(const struct xt_tgdtor_param *par)
Yasuyuki Kozakai11078c32006-12-12 00:29:02 -080087{
Jan Engelhardt92f3b2b2008-10-08 11:35:20 +020088 nf_ct_l3proto_module_put(par->family);
Yasuyuki Kozakai11078c32006-12-12 00:29:02 -080089}
90
Jan Engelhardte973a702009-06-12 18:42:12 +020091static struct xt_target connmark_tg_reg __read_mostly = {
92 .name = "CONNMARK",
93 .revision = 1,
94 .family = NFPROTO_UNSPEC,
95 .checkentry = connmark_tg_check,
96 .target = connmark_tg,
97 .targetsize = sizeof(struct xt_connmark_tginfo1),
98 .destroy = connmark_tg_destroy,
99 .me = THIS_MODULE,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100};
101
Jan Engelhardtd3c5ee62007-12-04 23:24:03 -0800102static int __init connmark_tg_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103{
Jan Engelhardte973a702009-06-12 18:42:12 +0200104 return xt_register_target(&connmark_tg_reg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105}
106
Jan Engelhardtd3c5ee62007-12-04 23:24:03 -0800107static void __exit connmark_tg_exit(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108{
Jan Engelhardte973a702009-06-12 18:42:12 +0200109 xt_unregister_target(&connmark_tg_reg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110}
111
Jan Engelhardtd3c5ee62007-12-04 23:24:03 -0800112module_init(connmark_tg_init);
113module_exit(connmark_tg_exit);