1/*
2 *  ebtable_nat
3 *
4 *	Authors:
5 *	Bart De Schuymer <bdschuym@pandora.be>
6 *
7 *  April, 2002
8 *
9 */
10
11#include <linux/netfilter_bridge/ebtables.h>
12#include <linux/module.h>
13
14#define NAT_VALID_HOOKS ((1 << NF_BR_PRE_ROUTING) | (1 << NF_BR_LOCAL_OUT) | \
15   (1 << NF_BR_POST_ROUTING))
16
17static struct ebt_entries initial_chains[] = {
18	{
19		.name	= "PREROUTING",
20		.policy	= EBT_ACCEPT,
21	},
22	{
23		.name	= "OUTPUT",
24		.policy	= EBT_ACCEPT,
25	},
26	{
27		.name	= "POSTROUTING",
28		.policy	= EBT_ACCEPT,
29	}
30};
31
32static struct ebt_replace_kernel initial_table = {
33	.name		= "nat",
34	.valid_hooks	= NAT_VALID_HOOKS,
35	.entries_size	= 3 * sizeof(struct ebt_entries),
36	.hook_entry	= {
37		[NF_BR_PRE_ROUTING]	= &initial_chains[0],
38		[NF_BR_LOCAL_OUT]	= &initial_chains[1],
39		[NF_BR_POST_ROUTING]	= &initial_chains[2],
40	},
41	.entries	= (char *)initial_chains,
42};
43
44static int check(const struct ebt_table_info *info, unsigned int valid_hooks)
45{
46	if (valid_hooks & ~NAT_VALID_HOOKS)
47		return -EINVAL;
48	return 0;
49}
50
51static struct ebt_table frame_nat = {
52	.name		= "nat",
53	.table		= &initial_table,
54	.valid_hooks	= NAT_VALID_HOOKS,
55	.check		= check,
56	.me		= THIS_MODULE,
57};
58
59static unsigned int
60ebt_nat_in(void *priv, struct sk_buff *skb,
61	   const struct nf_hook_state *state)
62{
63	return ebt_do_table(skb, state, state->net->xt.frame_nat);
64}
65
66static unsigned int
67ebt_nat_out(void *priv, struct sk_buff *skb,
68	    const struct nf_hook_state *state)
69{
70	return ebt_do_table(skb, state, state->net->xt.frame_nat);
71}
72
73static struct nf_hook_ops ebt_ops_nat[] __read_mostly = {
74	{
75		.hook		= ebt_nat_out,
76		.pf		= NFPROTO_BRIDGE,
77		.hooknum	= NF_BR_LOCAL_OUT,
78		.priority	= NF_BR_PRI_NAT_DST_OTHER,
79	},
80	{
81		.hook		= ebt_nat_out,
82		.pf		= NFPROTO_BRIDGE,
83		.hooknum	= NF_BR_POST_ROUTING,
84		.priority	= NF_BR_PRI_NAT_SRC,
85	},
86	{
87		.hook		= ebt_nat_in,
88		.pf		= NFPROTO_BRIDGE,
89		.hooknum	= NF_BR_PRE_ROUTING,
90		.priority	= NF_BR_PRI_NAT_DST_BRIDGED,
91	},
92};
93
94static int __net_init frame_nat_net_init(struct net *net)
95{
96	net->xt.frame_nat = ebt_register_table(net, &frame_nat);
97	return PTR_ERR_OR_ZERO(net->xt.frame_nat);
98}
99
100static void __net_exit frame_nat_net_exit(struct net *net)
101{
102	ebt_unregister_table(net, net->xt.frame_nat);
103}
104
105static struct pernet_operations frame_nat_net_ops = {
106	.init = frame_nat_net_init,
107	.exit = frame_nat_net_exit,
108};
109
110static int __init ebtable_nat_init(void)
111{
112	int ret;
113
114	ret = register_pernet_subsys(&frame_nat_net_ops);
115	if (ret < 0)
116		return ret;
117	ret = nf_register_hooks(ebt_ops_nat, ARRAY_SIZE(ebt_ops_nat));
118	if (ret < 0)
119		unregister_pernet_subsys(&frame_nat_net_ops);
120	return ret;
121}
122
123static void __exit ebtable_nat_fini(void)
124{
125	nf_unregister_hooks(ebt_ops_nat, ARRAY_SIZE(ebt_ops_nat));
126	unregister_pernet_subsys(&frame_nat_net_ops);
127}
128
129module_init(ebtable_nat_init);
130module_exit(ebtable_nat_fini);
131MODULE_LICENSE("GPL");
132