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
  51 connmark_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
  64 static 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
  80 static 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
  90 static 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
  96 struct 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
 103 static 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
 114 static 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
 126 static 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
 154 static int __init connmark_mt_init(void)
 155 {
 156         return xt_register_matches(connmark_mt_reg,
 157                ARRAY_SIZE(connmark_mt_reg));
 158 }
 159
 160 static void __exit connmark_mt_exit(void)
 161 {
 162         xt_unregister_matches(connmark_mt_reg, ARRAY_SIZE(connmark_mt_reg));
 163 }
 164
 165 module_init(connmark_mt_init);
 166 module_exit(connmark_mt_exit);