linux/net/netfilter/xt_connmark.c
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   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 \xC2\xA9 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
  51connmark_mt_v0(const struct sk_buff *skb, const struct xt_match_param *par)
  52{
  53        const struct xt_connmark_info *info = par->matchinfo;
  54        const struct nf_conn *ct;
  55        enum ip_conntrack_info ctinfo;
  56
  57        ct = nf_ct_get(skb, &ctinfo);
  58        if (!ct)
  59                return false;
  60
  61        return ((ct->mark & info->mask) == info->mark) ^ info->invert;
  62}
  63
  64static bool connmark_mt_check_v0(const struct xt_mtchk_param *par)
  65{
  66        const struct xt_connmark_info *cm = par->matchinfo;
  67
  68        if (cm->mark > 0xffffffff || cm->mask > 0xffffffff) {
  69                printk(KERN_WARNING "connmark: only support 32bit mark\n");
  70                return false;
  71        }
  72        if (nf_ct_l3proto_try_module_get(par->family) < 0) {
  73                printk(KERN_WARNING "can't load conntrack support for "
  74                                    "proto=%u\n", par->family);
  75                return false;
  76        }
  77        return true;
  78}
  79
  80static bool connmark_mt_check(const struct xt_mtchk_param *par)
  81{
  82        if (nf_ct_l3proto_try_module_get(par->family) < 0) {
  83                printk(KERN_WARNING "cannot load conntrack support for "
  84                       "proto=%u\n", par->family);
  85                return false;
  86        }
  87        return true;
  88}
  89
  90static void connmark_mt_destroy(const struct xt_mtdtor_param *par)
  91{
  92        nf_ct_l3proto_module_put(par->family);
  93}
  94
  95#ifdef CONFIG_COMPAT
  96struct compat_xt_connmark_info {
  97        compat_ulong_t  mark, mask;
  98        u_int8_t        invert;
  99        u_int8_t        __pad1;
 100        u_int16_t       __pad2;
 101};
 102
 103static void connmark_mt_compat_from_user_v0(void *dst, void *src)
 104{
 105        const struct compat_xt_connmark_info *cm = src;
 106        struct xt_connmark_info m = {
 107                .mark   = cm->mark,
 108                .mask   = cm->mask,
 109                .invert = cm->invert,
 110        };
 111        memcpy(dst, &m, sizeof(m));
 112}
 113
 114static int connmark_mt_compat_to_user_v0(void __user *dst, void *src)
 115{
 116        const struct xt_connmark_info *m = src;
 117        struct compat_xt_connmark_info cm = {
 118                .mark   = m->mark,
 119                .mask   = m->mask,
 120                .invert = m->invert,
 121        };
 122        return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0;
 123}
 124#endif /* CONFIG_COMPAT */
 125
 126static struct xt_match connmark_mt_reg[] __read_mostly = {
 127        {
 128                .name           = "connmark",
 129                .revision       = 0,
 130                .family         = NFPROTO_UNSPEC,
 131                .checkentry     = connmark_mt_check_v0,
 132                .match          = connmark_mt_v0,
 133                .destroy        = connmark_mt_destroy,
 134                .matchsize      = sizeof(struct xt_connmark_info),
 135#ifdef CONFIG_COMPAT
 136                .compatsize     = sizeof(struct compat_xt_connmark_info),
 137                .compat_from_user = connmark_mt_compat_from_user_v0,
 138                .compat_to_user = connmark_mt_compat_to_user_v0,
 139#endif
 140                .me             = THIS_MODULE
 141        },
 142        {
 143                .name           = "connmark",
 144                .revision       = 1,
 145                .family         = NFPROTO_UNSPEC,
 146                .checkentry     = connmark_mt_check,
 147                .match          = connmark_mt,
 148                .matchsize      = sizeof(struct xt_connmark_mtinfo1),
 149                .destroy        = connmark_mt_destroy,
 150                .me             = THIS_MODULE,
 151        },
 152};
 153
 154static int __init connmark_mt_init(void)
 155{
 156        return xt_register_matches(connmark_mt_reg,
 157               ARRAY_SIZE(connmark_mt_reg));
 158}
 159
 160static void __exit connmark_mt_exit(void)
 161{
 162        xt_unregister_matches(connmark_mt_reg, ARRAY_SIZE(connmark_mt_reg));
 163}
 164
 165module_init(connmark_mt_init);
 166module_exit(connmark_mt_exit);
 167