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, af: NFPROTO_IPV6, name: "nat");
69 if (WARN_ON_ONCE(!table))
70 return -ENOENT;
71
72 xt_nat_net = net_generic(net, id: ip6table_nat_net_id);
73 ops = kmemdup(p: nf_nat_ipv6_ops, size: 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: &ops[i]);
80 if (ret) {
81 while (i)
82 nf_nat_ipv6_unregister_fn(net, ops: &ops[--i]);
83
84 kfree(objp: 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, id: 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: &ops[i]);
104
105 kfree(objp: 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, table: &nf_nat_ipv6_table, repl,
117 NULL);
118 if (ret < 0) {
119 kfree(objp: repl);
120 return ret;
121 }
122
123 ret = ip6t_nat_register_lookups(net);
124 if (ret < 0)
125 ip6t_unregister_table_exit(net, name: "nat");
126
127 kfree(objp: 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, name: "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(t: &nf_nat_ipv6_table,
151 table_init: 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(t: &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(t: &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

source code of linux/net/ipv6/netfilter/ip6table_nat.c