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("X_tables realm match");
  22 MODULE_ALIAS("ipt_realm");
  23
  24 static bool
  25 match(const struct sk_buff *skb,
  26       const struct net_device *in,
  27       const struct net_device *out,
  28       const struct xt_match *match,
  29       const void *matchinfo,
  30       int offset,
  31       unsigned int protoff,
  32       bool *hotdrop)
  33 {
  34         const struct xt_realm_info *info = matchinfo;
  35         const struct dst_entry *dst = skb->dst;
  36
  37         return (info->id == (dst->tclassid & info->mask)) ^ info->invert;
  38 }
  39
  40 static struct xt_match realm_match __read_mostly = {
  41         .name           = "realm",
  42         .match          = match,
  43         .matchsize      = sizeof(struct xt_realm_info),
  44         .hooks          = (1 << NF_IP_POST_ROUTING) | (1 << NF_IP_FORWARD) |
  45                           (1 << NF_IP_LOCAL_OUT) | (1 << NF_IP_LOCAL_IN),
  46         .family         = AF_INET,
  47         .me             = THIS_MODULE
  48 };
  49
  50 static int __init xt_realm_init(void)
  51 {
  52         return xt_register_match(&realm_match);
  53 }
  54
  55 static void __exit xt_realm_fini(void)
  56 {
  57         xt_unregister_match(&realm_match);
  58 }
  59
  60 module_init(xt_realm_init);
  61 module_exit(xt_realm_fini);