1 /*
2  *  ebtable_broute
3  *
4  *	Authors:
5  *	Bart De Schuymer <bdschuym@pandora.be>
6  *
7  *  April, 2002
8  *
9  *  This table lets you choose between routing and bridging for frames
10  *  entering on a bridge enslaved nic. This table is traversed before any
11  *  other ebtables table. See net/bridge/br_input.c.
12  */
13 
14 #include <linux/netfilter_bridge/ebtables.h>
15 #include <linux/module.h>
16 #include <linux/if_bridge.h>
17 
18 /* EBT_ACCEPT means the frame will be bridged
19  * EBT_DROP means the frame will be routed
20  */
21 static struct ebt_entries initial_chain = {
22 	.name		= "BROUTING",
23 	.policy		= EBT_ACCEPT,
24 };
25 
26 static struct ebt_replace_kernel initial_table = {
27 	.name		= "broute",
28 	.valid_hooks	= 1 << NF_BR_BROUTING,
29 	.entries_size	= sizeof(struct ebt_entries),
30 	.hook_entry	= {
31 		[NF_BR_BROUTING]	= &initial_chain,
32 	},
33 	.entries	= (char *)&initial_chain,
34 };
35 
36 static int check(const struct ebt_table_info *info, unsigned int valid_hooks)
37 {
38 	if (valid_hooks & ~(1 << NF_BR_BROUTING))
39 		return -EINVAL;
40 	return 0;
41 }
42 
43 static const struct ebt_table broute_table = {
44 	.name		= "broute",
45 	.table		= &initial_table,
46 	.valid_hooks	= 1 << NF_BR_BROUTING,
47 	.check		= check,
48 	.me		= THIS_MODULE,
49 };
50 
51 static int ebt_broute(struct sk_buff *skb)
52 {
53 	struct nf_hook_state state;
54 	int ret;
55 
56 	nf_hook_state_init(&state, NF_BR_BROUTING,
57 			   NFPROTO_BRIDGE, skb->dev, NULL, NULL,
58 			   dev_net(skb->dev), NULL);
59 
60 	ret = ebt_do_table(skb, &state, state.net->xt.broute_table);
61 	if (ret == NF_DROP)
62 		return 1; /* route it */
63 	return 0; /* bridge it */
64 }
65 
66 static int __net_init broute_net_init(struct net *net)
67 {
68 	net->xt.broute_table = ebt_register_table(net, &broute_table, NULL);
69 	return PTR_ERR_OR_ZERO(net->xt.broute_table);
70 }
71 
72 static void __net_exit broute_net_exit(struct net *net)
73 {
74 	ebt_unregister_table(net, net->xt.broute_table, NULL);
75 }
76 
77 static struct pernet_operations broute_net_ops = {
78 	.init = broute_net_init,
79 	.exit = broute_net_exit,
80 };
81 
82 static int __init ebtable_broute_init(void)
83 {
84 	int ret;
85 
86 	ret = register_pernet_subsys(&broute_net_ops);
87 	if (ret < 0)
88 		return ret;
89 	/* see br_input.c */
90 	RCU_INIT_POINTER(br_should_route_hook,
91 			   (br_should_route_hook_t *)ebt_broute);
92 	return 0;
93 }
94 
95 static void __exit ebtable_broute_fini(void)
96 {
97 	RCU_INIT_POINTER(br_should_route_hook, NULL);
98 	synchronize_net();
99 	unregister_pernet_subsys(&broute_net_ops);
100 }
101 
102 module_init(ebtable_broute_init);
103 module_exit(ebtable_broute_fini);
104 MODULE_LICENSE("GPL");
105