LXR linux/net/netfilter/xt

   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);
  88