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
realm_mt(const struct sk_buff * skb,struct xt_action_param * par)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 
realm_mt_init(void)40 static int __init realm_mt_init(void)
41 {
42 	return xt_register_match(&realm_mt_reg);
43 }
44 
realm_mt_exit(void)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);
52