net/netfilter/xt_realm.c

   1 /* IP tables module for matching the routing realm
   2  *
   3  * $Id: ipt_realm.c,v 1.3 2004/03/05 13:25:40 laforge Exp $
   4  *
   5  * (C) 2003 by Sampsa Ranta <sampsa@netsonic.fi>
   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 version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/netdevice.h>
  15 #include <net/route.h>
  16
  17 #include <linux/netfilter_ipv4.h>
  18 #include <linux/netfilter/xt_realm.h>
  19 #include <linux/netfilter/x_tables.h>
  20
  21 MODULE_AUTHOR("Sampsa Ranta <sampsa@netsonic.fi>");
  22 MODULE_LICENSE("GPL");
  23 MODULE_DESCRIPTION("X_tables realm match");
  24 MODULE_ALIAS("ipt_realm");
  25
  26 static int
  27 match(const struct sk_buff *skb,
  28       const struct net_device *in,
  29       const struct net_device *out,
  30       const struct xt_match *match,
  31       const void *matchinfo,
  32       int offset,
  33       unsigned int protoff,
  34       int *hotdrop)
  35 {
  36         const struct xt_realm_info *info = matchinfo;
  37         struct dst_entry *dst = skb->dst;
  38
  39         return (info->id == (dst->tclassid & info->mask)) ^ info->invert;
  40 }
  41
  42 static struct xt_match realm_match = {
  43         .name           = "realm",
  44         .match          = match,
  45         .matchsize      = sizeof(struct xt_realm_info),
  46         .hooks          = (1 << NF_IP_POST_ROUTING) | (1 << NF_IP_FORWARD) |
  47                           (1 << NF_IP_LOCAL_OUT) | (1 << NF_IP_LOCAL_IN),
  48         .me             = THIS_MODULE
  49 };
  50
  51 static int __init init(void)
  52 {
  53         return xt_register_match(AF_INET, &realm_match);
  54 }
  55
  56 static void __exit fini(void)
  57 {
  58         xt_unregister_match(AF_INET, &realm_match);
  59 }
  60
  61 module_init(init);
  62 module_exit(fini);