1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
4 *
5 * Based on Rusty Russell's IPv4 NAT code. Development of IPv6 NAT
6 * funded by Astaro.
7 */
8
9#include <linux/module.h>
10#include <linux/netfilter.h>
11#include <linux/netfilter_ipv6.h>
12#include <linux/netfilter_ipv6/ip6_tables.h>
13#include <linux/ipv6.h>
14#include <net/ipv6.h>
15
16#include <net/netfilter/nf_nat.h>
17
18struct ip6table_nat_pernet {
19	struct nf_hook_ops *nf_nat_ops;
20};
21
22static unsigned int ip6table_nat_net_id __read_mostly;
23
24static const struct xt_table nf_nat_ipv6_table = {
25	.name		= "nat",
26	.valid_hooks	= (1 << NF_INET_PRE_ROUTING) |
27			  (1 << NF_INET_POST_ROUTING) |
28			  (1 << NF_INET_LOCAL_OUT) |
29			  (1 << NF_INET_LOCAL_IN),
30	.me		= THIS_MODULE,
31	.af		= NFPROTO_IPV6,
32};
33
34static const struct nf_hook_ops nf_nat_ipv6_ops[] = {
35	{
36		.hook		= ip6t_do_table,
37		.pf		= NFPROTO_IPV6,
38		.hooknum	= NF_INET_PRE_ROUTING,
39		.priority	= NF_IP6_PRI_NAT_DST,
40	},
41	{
42		.hook		= ip6t_do_table,
43		.pf		= NFPROTO_IPV6,
44		.hooknum	= NF_INET_POST_ROUTING,
45		.priority	= NF_IP6_PRI_NAT_SRC,
46	},
47	{
48		.hook		= ip6t_do_table,
49		.pf		= NFPROTO_IPV6,
50		.hooknum	= NF_INET_LOCAL_OUT,
51		.priority	= NF_IP6_PRI_NAT_DST,
52	},
53	{
54		.hook		= ip6t_do_table,
55		.pf		= NFPROTO_IPV6,
56		.hooknum	= NF_INET_LOCAL_IN,
57		.priority	= NF_IP6_PRI_NAT_SRC,
58	},
59};
60
61static int ip6t_nat_register_lookups(struct net *net)
62{
63	struct ip6table_nat_pernet *xt_nat_net;
64	struct nf_hook_ops *ops;
65	struct xt_table *table;
66	int i, ret;
67
68	table = xt_find_table(net, NFPROTO_IPV6, "nat");
69	if (WARN_ON_ONCE(!table))
70		return -ENOENT;
71
72	xt_nat_net = net_generic(net, ip6table_nat_net_id);
73	ops = kmemdup(nf_nat_ipv6_ops, sizeof(nf_nat_ipv6_ops), GFP_KERNEL);
74	if (!ops)
75		return -ENOMEM;
76
77	for (i = 0; i < ARRAY_SIZE(nf_nat_ipv6_ops); i++) {
78		ops[i].priv = table;
79		ret = nf_nat_ipv6_register_fn(net, &ops[i]);
80		if (ret) {
81			while (i)
82				nf_nat_ipv6_unregister_fn(net, &ops[--i]);
83
84			kfree(ops);
85			return ret;
86		}
87	}
88
89	xt_nat_net->nf_nat_ops = ops;
90	return 0;
91}
92
93static void ip6t_nat_unregister_lookups(struct net *net)
94{
95	struct ip6table_nat_pernet *xt_nat_net = net_generic(net, ip6table_nat_net_id);
96	struct nf_hook_ops *ops = xt_nat_net->nf_nat_ops;
97	int i;
98
99	if (!ops)
100		return;
101
102	for (i = 0; i < ARRAY_SIZE(nf_nat_ipv6_ops); i++)
103		nf_nat_ipv6_unregister_fn(net, &ops[i]);
104
105	kfree(ops);
106}
107
108static int ip6table_nat_table_init(struct net *net)
109{
110	struct ip6t_replace *repl;
111	int ret;
112
113	repl = ip6t_alloc_initial_table(&nf_nat_ipv6_table);
114	if (repl == NULL)
115		return -ENOMEM;
116	ret = ip6t_register_table(net, &nf_nat_ipv6_table, repl,
117				  NULL);
118	if (ret < 0) {
119		kfree(repl);
120		return ret;
121	}
122
123	ret = ip6t_nat_register_lookups(net);
124	if (ret < 0)
125		ip6t_unregister_table_exit(net, "nat");
126
127	kfree(repl);
128	return ret;
129}
130
131static void __net_exit ip6table_nat_net_pre_exit(struct net *net)
132{
133	ip6t_nat_unregister_lookups(net);
134}
135
136static void __net_exit ip6table_nat_net_exit(struct net *net)
137{
138	ip6t_unregister_table_exit(net, "nat");
139}
140
141static struct pernet_operations ip6table_nat_net_ops = {
142	.pre_exit = ip6table_nat_net_pre_exit,
143	.exit	= ip6table_nat_net_exit,
144	.id	= &ip6table_nat_net_id,
145	.size	= sizeof(struct ip6table_nat_pernet),
146};
147
148static int __init ip6table_nat_init(void)
149{
150	int ret = xt_register_template(&nf_nat_ipv6_table,
151				       ip6table_nat_table_init);
152
153	if (ret < 0)
154		return ret;
155
156	ret = register_pernet_subsys(&ip6table_nat_net_ops);
157	if (ret)
158		xt_unregister_template(&nf_nat_ipv6_table);
159
160	return ret;
161}
162
163static void __exit ip6table_nat_exit(void)
164{
165	unregister_pernet_subsys(&ip6table_nat_net_ops);
166	xt_unregister_template(&nf_nat_ipv6_table);
167}
168
169module_init(ip6table_nat_init);
170module_exit(ip6table_nat_exit);
171
172MODULE_LICENSE("GPL");
173MODULE_DESCRIPTION("Ip6tables legacy nat table");
174