LXR linux/net/netfilter/xt

   1/* This kernel module matches connection mark values set by the
   2 * CONNMARK target
   3 *
   4 * Copyright (C) 2002,2004 MARA Systems AB <http://www.marasystems.com>
   5 * by Henrik Nordstrom <hno@marasystems.com>
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License as published by
   9 * the Free Software Foundation; either version 2 of the License, or
  10 * (at your option) any later version.
  11 *
  12 * This program is distributed in the hope that it will be useful,
  13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 * GNU General Public License for more details.
  16 *
  17 * You should have received a copy of the GNU General Public License
  18 * along with this program; if not, write to the Free Software
  19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20 */
  21
  22#include <linux/module.h>
  23#include <linux/skbuff.h>
  24#include <net/netfilter/nf_conntrack.h>
  25#include <linux/netfilter/x_tables.h>
  26#include <linux/netfilter/xt_connmark.h>
  27
  28MODULE_AUTHOR("Henrik Nordstrom <hno@marasystems.com>");
  29MODULE_DESCRIPTION("IP tables connmark match module");
  30MODULE_LICENSE("GPL");
  31MODULE_ALIAS("ipt_connmark");
  32MODULE_ALIAS("ip6t_connmark");
  33
  34static bool
  35match(const struct sk_buff *skb,
  36      const struct net_device *in,
  37      const struct net_device *out,
  38      const struct xt_match *match,
  39      const void *matchinfo,
  40      int offset,
  41      unsigned int protoff,
  42      bool *hotdrop)
  43{
  44        const struct xt_connmark_info *info = matchinfo;
  45        const struct nf_conn *ct;
  46        enum ip_conntrack_info ctinfo;
  47
  48        ct = nf_ct_get(skb, &ctinfo);
  49        if (!ct)
  50                return false;
  51
  52        return ((ct->mark & info->mask) == info->mark) ^ info->invert;
  53}
  54
  55static bool
  56checkentry(const char *tablename,
  57           const void *ip,
  58           const struct xt_match *match,
  59           void *matchinfo,
  60           unsigned int hook_mask)
  61{
  62        const struct xt_connmark_info *cm = matchinfo;
  63
  64        if (cm->mark > 0xffffffff || cm->mask > 0xffffffff) {
  65                printk(KERN_WARNING "connmark: only support 32bit mark\n");
  66                return false;
  67        }
  68        if (nf_ct_l3proto_try_module_get(match->family) < 0) {
  69                printk(KERN_WARNING "can't load conntrack support for "
  70                                    "proto=%d\n", match->family);
  71                return false;
  72        }
  73        return true;
  74}
  75
  76static void
  77destroy(const struct xt_match *match, void *matchinfo)
  78{
  79        nf_ct_l3proto_module_put(match->family);
  80}
  81
  82#ifdef CONFIG_COMPAT
  83struct compat_xt_connmark_info {
  84        compat_ulong_t  mark, mask;
  85        u_int8_t        invert;
  86        u_int8_t        __pad1;
  87        u_int16_t       __pad2;
  88};
  89
  90static void compat_from_user(void *dst, void *src)
  91{
  92        const struct compat_xt_connmark_info *cm = src;
  93        struct xt_connmark_info m = {
  94                .mark   = cm->mark,
  95                .mask   = cm->mask,
  96                .invert = cm->invert,
  97        };
  98        memcpy(dst, &m, sizeof(m));
  99}
 100
 101static int compat_to_user(void __user *dst, void *src)
 102{
 103        const struct xt_connmark_info *m = src;
 104        struct compat_xt_connmark_info cm = {
 105                .mark   = m->mark,
 106                .mask   = m->mask,
 107                .invert = m->invert,
 108        };
 109        return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0;
 110}
 111#endif /* CONFIG_COMPAT */
 112
 113static struct xt_match xt_connmark_match[] __read_mostly = {
 114        {
 115                .name           = "connmark",
 116                .family         = AF_INET,
 117                .checkentry     = checkentry,
 118                .match          = match,
 119                .destroy        = destroy,
 120                .matchsize      = sizeof(struct xt_connmark_info),
 121#ifdef CONFIG_COMPAT
 122                .compatsize     = sizeof(struct compat_xt_connmark_info),
 123                .compat_from_user = compat_from_user,
 124                .compat_to_user = compat_to_user,
 125#endif
 126                .me             = THIS_MODULE
 127        },
 128        {
 129                .name           = "connmark",
 130                .family         = AF_INET6,
 131                .checkentry     = checkentry,
 132                .match          = match,
 133                .destroy        = destroy,
 134                .matchsize      = sizeof(struct xt_connmark_info),
 135                .me             = THIS_MODULE
 136        },
 137};
 138
 139static int __init xt_connmark_init(void)
 140{
 141        return xt_register_matches(xt_connmark_match,
 142                                   ARRAY_SIZE(xt_connmark_match));
 143}
 144
 145static void __exit xt_connmark_fini(void)
 146{
 147        xt_unregister_matches(xt_connmark_match, ARRAY_SIZE(xt_connmark_match));
 148}
 149
 150module_init(xt_connmark_init);
 151module_exit(xt_connmark_fini);
 152