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
  30 MODULE_AUTHOR("Henrik Nordstrom <hno@marasystems.com>");
  31 MODULE_DESCRIPTION("Xtables: connection mark match");
  32 MODULE_LICENSE("GPL");
  33 MODULE_ALIAS("ipt_connmark");
  34 MODULE_ALIAS("ip6t_connmark");
  35
  36 static bool
  37 connmark_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
  50 static 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
  60 static void connmark_mt_destroy(const struct xt_mtdtor_param *par)
  61 {
  62         nf_ct_l3proto_module_put(par->family);
  63 }
  64
  65 static 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
  76 static int __init connmark_mt_init(void)
  77 {
  78         return xt_register_match(&connmark_mt_reg);
  79 }
  80
  81 static void __exit connmark_mt_exit(void)
  82 {
  83         xt_unregister_match(&connmark_mt_reg);
  84 }
  85
  86 module_init(connmark_mt_init);
  87 module_exit(connmark_mt_exit);