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 net_device *in,
  38             const struct net_device *out, const struct xt_match *match,
  39             const void *matchinfo, int offset, unsigned int protoff,
  40             bool *hotdrop)
  41 {
  42         const struct xt_connmark_mtinfo1 *info = matchinfo;
  43         enum ip_conntrack_info ctinfo;
  44         const struct nf_conn *ct;
  45
  46         ct = nf_ct_get(skb, &ctinfo);
  47         if (ct == NULL)
  48                 return false;
  49
  50         return ((ct->mark & info->mask) == info->mark) ^ info->invert;
  51 }
  52
  53 static bool
  54 connmark_mt_v0(const struct sk_buff *skb, const struct net_device *in,
  55                const struct net_device *out, const struct xt_match *match,
  56                const void *matchinfo, int offset, unsigned int protoff,
  57                bool *hotdrop)
  58 {
  59         const struct xt_connmark_info *info = matchinfo;
  60         const struct nf_conn *ct;
  61         enum ip_conntrack_info ctinfo;
  62
  63         ct = nf_ct_get(skb, &ctinfo);
  64         if (!ct)
  65                 return false;
  66
  67         return ((ct->mark & info->mask) == info->mark) ^ info->invert;
  68 }
  69
  70 static bool
  71 connmark_mt_check_v0(const char *tablename, const void *ip,
  72                      const struct xt_match *match, void *matchinfo,
  73                      unsigned int hook_mask)
  74 {
  75         const struct xt_connmark_info *cm = matchinfo;
  76
  77         if (cm->mark > 0xffffffff || cm->mask > 0xffffffff) {
  78                 printk(KERN_WARNING "connmark: only support 32bit mark\n");
  79                 return false;
  80         }
  81         if (nf_ct_l3proto_try_module_get(match->family) < 0) {
  82                 printk(KERN_WARNING "can't load conntrack support for "
  83                                     "proto=%u\n", match->family);
  84                 return false;
  85         }
  86         return true;
  87 }
  88
  89 static bool
  90 connmark_mt_check(const char *tablename, const void *ip,
  91                   const struct xt_match *match, void *matchinfo,
  92                   unsigned int hook_mask)
  93 {
  94         if (nf_ct_l3proto_try_module_get(match->family) < 0) {
  95                 printk(KERN_WARNING "cannot load conntrack support for "
  96                        "proto=%u\n", match->family);
  97                 return false;
  98         }
  99         return true;
 100 }
 101
 102 static void
 103 connmark_mt_destroy(const struct xt_match *match, void *matchinfo)
 104 {
 105         nf_ct_l3proto_module_put(match->family);
 106 }
 107
 108 #ifdef CONFIG_COMPAT
 109 struct compat_xt_connmark_info {
 110         compat_ulong_t  mark, mask;
 111         u_int8_t        invert;
 112         u_int8_t        __pad1;
 113         u_int16_t       __pad2;
 114 };
 115
 116 static void connmark_mt_compat_from_user_v0(void *dst, void *src)
 117 {
 118         const struct compat_xt_connmark_info *cm = src;
 119         struct xt_connmark_info m = {
 120                 .mark   = cm->mark,
 121                 .mask   = cm->mask,
 122                 .invert = cm->invert,
 123         };
 124         memcpy(dst, &m, sizeof(m));
 125 }
 126
 127 static int connmark_mt_compat_to_user_v0(void __user *dst, void *src)
 128 {
 129         const struct xt_connmark_info *m = src;
 130         struct compat_xt_connmark_info cm = {
 131                 .mark   = m->mark,
 132                 .mask   = m->mask,
 133                 .invert = m->invert,
 134         };
 135         return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0;
 136 }
 137 #endif /* CONFIG_COMPAT */
 138
 139 static struct xt_match connmark_mt_reg[] __read_mostly = {
 140         {
 141                 .name           = "connmark",
 142                 .revision       = 0,
 143                 .family         = AF_INET,
 144                 .checkentry     = connmark_mt_check_v0,
 145                 .match          = connmark_mt_v0,
 146                 .destroy        = connmark_mt_destroy,
 147                 .matchsize      = sizeof(struct xt_connmark_info),
 148 #ifdef CONFIG_COMPAT
 149                 .compatsize     = sizeof(struct compat_xt_connmark_info),
 150                 .compat_from_user = connmark_mt_compat_from_user_v0,
 151                 .compat_to_user = connmark_mt_compat_to_user_v0,
 152 #endif
 153                 .me             = THIS_MODULE
 154         },
 155         {
 156                 .name           = "connmark",
 157                 .revision       = 0,
 158                 .family         = AF_INET6,
 159                 .checkentry     = connmark_mt_check_v0,
 160                 .match          = connmark_mt_v0,
 161                 .destroy        = connmark_mt_destroy,
 162                 .matchsize      = sizeof(struct xt_connmark_info),
 163 #ifdef CONFIG_COMPAT
 164                 .compatsize     = sizeof(struct compat_xt_connmark_info),
 165                 .compat_from_user = connmark_mt_compat_from_user_v0,
 166                 .compat_to_user = connmark_mt_compat_to_user_v0,
 167 #endif
 168                 .me             = THIS_MODULE
 169         },
 170         {
 171                 .name           = "connmark",
 172                 .revision       = 1,
 173                 .family         = AF_INET,
 174                 .checkentry     = connmark_mt_check,
 175                 .match          = connmark_mt,
 176                 .matchsize      = sizeof(struct xt_connmark_mtinfo1),
 177                 .destroy        = connmark_mt_destroy,
 178                 .me             = THIS_MODULE,
 179         },
 180         {
 181                 .name           = "connmark",
 182                 .revision       = 1,
 183                 .family         = AF_INET6,
 184                 .checkentry     = connmark_mt_check,
 185                 .match          = connmark_mt,
 186                 .matchsize      = sizeof(struct xt_connmark_mtinfo1),
 187                 .destroy        = connmark_mt_destroy,
 188                 .me             = THIS_MODULE,
 189         },
 190 };
 191
 192 static int __init connmark_mt_init(void)
 193 {
 194         return xt_register_matches(connmark_mt_reg,
 195                ARRAY_SIZE(connmark_mt_reg));
 196 }
 197
 198 static void __exit connmark_mt_exit(void)
 199 {
 200         xt_unregister_matches(connmark_mt_reg, ARRAY_SIZE(connmark_mt_reg));
 201 }
 202
 203 module_init(connmark_mt_init);
 204 module_exit(connmark_mt_exit);