net/netfilter/xt_realm.c

   1 /* IP tables module for matching the routing realm
   2  *
   3  * (C) 2003 by Sampsa Ranta <sampsa@netsonic.fi>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/skbuff.h>
  12 #include <linux/netdevice.h>
  13 #include <net/route.h>
  14
  15 #include <linux/netfilter_ipv4.h>
  16 #include <linux/netfilter/xt_realm.h>
  17 #include <linux/netfilter/x_tables.h>
  18
  19 MODULE_AUTHOR("Sampsa Ranta <sampsa@netsonic.fi>");
  20 MODULE_LICENSE("GPL");
  21 MODULE_DESCRIPTION("Xtables: Routing realm match");
  22 MODULE_ALIAS("ipt_realm");
  23
  24 static bool
  25 realm_mt(const struct sk_buff *skb, const struct net_device *in,
  26          const struct net_device *out, const struct xt_match *match,
  27          const void *matchinfo, int offset, unsigned int protoff,
  28          bool *hotdrop)
  29 {
  30         const struct xt_realm_info *info = matchinfo;
  31         const struct dst_entry *dst = skb->dst;
  32
  33         return (info->id == (dst->tclassid & info->mask)) ^ info->invert;
  34 }
  35
  36 static struct xt_match realm_mt_reg __read_mostly = {
  37         .name           = "realm",
  38         .match          = realm_mt,
  39         .matchsize      = sizeof(struct xt_realm_info),
  40         .hooks          = (1 << NF_INET_POST_ROUTING) | (1 << NF_INET_FORWARD) |
  41                           (1 << NF_INET_LOCAL_OUT) | (1 << NF_INET_LOCAL_IN),
  42         .family         = AF_INET,
  43         .me             = THIS_MODULE
  44 };
  45
  46 static int __init realm_mt_init(void)
  47 {
  48         return xt_register_match(&realm_mt_reg);
  49 }
  50
  51 static void __exit realm_mt_exit(void)
  52 {
  53         xt_unregister_match(&realm_mt_reg);
  54 }
  55
  56 module_init(realm_mt_init);
  57 module_exit(realm_mt_exit);