net/netfilter/xt_realm.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* IP tables module for matching the routing realm
   3  *
   4  * (C) 2003 by Sampsa Ranta <sampsa@netsonic.fi>
   5  */
   6
   7 #include <linux/module.h>
   8 #include <linux/skbuff.h>
   9 #include <linux/netdevice.h>
  10 #include <net/route.h>
  11
  12 #include <linux/netfilter_ipv4.h>
  13 #include <linux/netfilter/xt_realm.h>
  14 #include <linux/netfilter/x_tables.h>
  15
  16 MODULE_AUTHOR("Sampsa Ranta <sampsa@netsonic.fi>");
  17 MODULE_LICENSE("GPL");
  18 MODULE_DESCRIPTION("Xtables: Routing realm match");
  19 MODULE_ALIAS("ipt_realm");
  20
  21 static bool
  22 realm_mt(const struct sk_buff *skb, struct xt_action_param *par)
  23 {
  24         const struct xt_realm_info *info = par->matchinfo;
  25         const struct dst_entry *dst = skb_dst(skb);
  26
  27         return (info->id == (dst->tclassid & info->mask)) ^ info->invert;
  28 }
  29
  30 static struct xt_match realm_mt_reg __read_mostly = {
  31         .name           = "realm",
  32         .match          = realm_mt,
  33         .matchsize      = sizeof(struct xt_realm_info),
  34         .hooks          = (1 << NF_INET_POST_ROUTING) | (1 << NF_INET_FORWARD) |
  35                           (1 << NF_INET_LOCAL_OUT) | (1 << NF_INET_LOCAL_IN),
  36         .family         = NFPROTO_UNSPEC,
  37         .me             = THIS_MODULE
  38 };
  39
  40 static int __init realm_mt_init(void)
  41 {
  42         return xt_register_match(&realm_mt_reg);
  43 }
  44
  45 static void __exit realm_mt_exit(void)
  46 {
  47         xt_unregister_match(&realm_mt_reg);
  48 }
  49
  50 module_init(realm_mt_init);
  51 module_exit(realm_mt_exit);