1/*
2 * Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * Based on Rusty Russell's IPv4 NAT code. Development of IPv6 NAT
9 * funded by Astaro.
10 */
11
12#include <linux/module.h>
13#include <linux/netfilter.h>
14#include <linux/netfilter_ipv6.h>
15#include <linux/netfilter_ipv6/ip6_tables.h>
16#include <linux/ipv6.h>
17#include <net/ipv6.h>
18
19#include <net/netfilter/nf_nat.h>
20#include <net/netfilter/nf_nat_core.h>
21#include <net/netfilter/nf_nat_l3proto.h>
22
23static const struct xt_table nf_nat_ipv6_table = {
24	.name		= "nat",
25	.valid_hooks	= (1 << NF_INET_PRE_ROUTING) |
26			  (1 << NF_INET_POST_ROUTING) |
27			  (1 << NF_INET_LOCAL_OUT) |
28			  (1 << NF_INET_LOCAL_IN),
29	.me		= THIS_MODULE,
30	.af		= NFPROTO_IPV6,
31};
32
33static unsigned int ip6table_nat_do_chain(const struct nf_hook_ops *ops,
34					  struct sk_buff *skb,
35					  const struct nf_hook_state *state,
36					  struct nf_conn *ct)
37{
38	struct net *net = nf_ct_net(ct);
39
40	return ip6t_do_table(skb, ops->hooknum, state, net->ipv6.ip6table_nat);
41}
42
43static unsigned int ip6table_nat_fn(const struct nf_hook_ops *ops,
44				    struct sk_buff *skb,
45				    const struct nf_hook_state *state)
46{
47	return nf_nat_ipv6_fn(ops, skb, state, ip6table_nat_do_chain);
48}
49
50static unsigned int ip6table_nat_in(const struct nf_hook_ops *ops,
51				    struct sk_buff *skb,
52				    const struct nf_hook_state *state)
53{
54	return nf_nat_ipv6_in(ops, skb, state, ip6table_nat_do_chain);
55}
56
57static unsigned int ip6table_nat_out(const struct nf_hook_ops *ops,
58				     struct sk_buff *skb,
59				     const struct nf_hook_state *state)
60{
61	return nf_nat_ipv6_out(ops, skb, state, ip6table_nat_do_chain);
62}
63
64static unsigned int ip6table_nat_local_fn(const struct nf_hook_ops *ops,
65					  struct sk_buff *skb,
66					  const struct nf_hook_state *state)
67{
68	return nf_nat_ipv6_local_fn(ops, skb, state, ip6table_nat_do_chain);
69}
70
71static struct nf_hook_ops nf_nat_ipv6_ops[] __read_mostly = {
72	/* Before packet filtering, change destination */
73	{
74		.hook		= ip6table_nat_in,
75		.owner		= THIS_MODULE,
76		.pf		= NFPROTO_IPV6,
77		.hooknum	= NF_INET_PRE_ROUTING,
78		.priority	= NF_IP6_PRI_NAT_DST,
79	},
80	/* After packet filtering, change source */
81	{
82		.hook		= ip6table_nat_out,
83		.owner		= THIS_MODULE,
84		.pf		= NFPROTO_IPV6,
85		.hooknum	= NF_INET_POST_ROUTING,
86		.priority	= NF_IP6_PRI_NAT_SRC,
87	},
88	/* Before packet filtering, change destination */
89	{
90		.hook		= ip6table_nat_local_fn,
91		.owner		= THIS_MODULE,
92		.pf		= NFPROTO_IPV6,
93		.hooknum	= NF_INET_LOCAL_OUT,
94		.priority	= NF_IP6_PRI_NAT_DST,
95	},
96	/* After packet filtering, change source */
97	{
98		.hook		= ip6table_nat_fn,
99		.owner		= THIS_MODULE,
100		.pf		= NFPROTO_IPV6,
101		.hooknum	= NF_INET_LOCAL_IN,
102		.priority	= NF_IP6_PRI_NAT_SRC,
103	},
104};
105
106static int __net_init ip6table_nat_net_init(struct net *net)
107{
108	struct ip6t_replace *repl;
109
110	repl = ip6t_alloc_initial_table(&nf_nat_ipv6_table);
111	if (repl == NULL)
112		return -ENOMEM;
113	net->ipv6.ip6table_nat = ip6t_register_table(net, &nf_nat_ipv6_table, repl);
114	kfree(repl);
115	return PTR_ERR_OR_ZERO(net->ipv6.ip6table_nat);
116}
117
118static void __net_exit ip6table_nat_net_exit(struct net *net)
119{
120	ip6t_unregister_table(net, net->ipv6.ip6table_nat);
121}
122
123static struct pernet_operations ip6table_nat_net_ops = {
124	.init	= ip6table_nat_net_init,
125	.exit	= ip6table_nat_net_exit,
126};
127
128static int __init ip6table_nat_init(void)
129{
130	int err;
131
132	err = register_pernet_subsys(&ip6table_nat_net_ops);
133	if (err < 0)
134		goto err1;
135
136	err = nf_register_hooks(nf_nat_ipv6_ops, ARRAY_SIZE(nf_nat_ipv6_ops));
137	if (err < 0)
138		goto err2;
139	return 0;
140
141err2:
142	unregister_pernet_subsys(&ip6table_nat_net_ops);
143err1:
144	return err;
145}
146
147static void __exit ip6table_nat_exit(void)
148{
149	nf_unregister_hooks(nf_nat_ipv6_ops, ARRAY_SIZE(nf_nat_ipv6_ops));
150	unregister_pernet_subsys(&ip6table_nat_net_ops);
151}
152
153module_init(ip6table_nat_init);
154module_exit(ip6table_nat_exit);
155
156MODULE_LICENSE("GPL");
157