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
18 struct ip6table_nat_pernet {
19 struct nf_hook_ops *nf_nat_ops;
20 };
21
22 static unsigned int ip6table_nat_net_id __read_mostly;
23
24 static 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
34 static 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
ip6t_nat_register_lookups(struct net * net)61 static 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
ip6t_nat_unregister_lookups(struct net * net)93 static 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
ip6table_nat_table_init(struct net * net)108 static 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
ip6table_nat_net_pre_exit(struct net * net)131 static void __net_exit ip6table_nat_net_pre_exit(struct net *net)
132 {
133 ip6t_nat_unregister_lookups(net);
134 }
135
ip6table_nat_net_exit(struct net * net)136 static void __net_exit ip6table_nat_net_exit(struct net *net)
137 {
138 ip6t_unregister_table_exit(net, "nat");
139 }
140
141 static 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
ip6table_nat_init(void)148 static int __init ip6table_nat_init(void)
149 {
150 int ret;
151
152 /* net->gen->ptr[ip6table_nat_net_id] must be allocated
153 * before calling ip6t_nat_register_lookups().
154 */
155 ret = register_pernet_subsys(&ip6table_nat_net_ops);
156 if (ret < 0)
157 return ret;
158
159 ret = xt_register_template(&nf_nat_ipv6_table,
160 ip6table_nat_table_init);
161 if (ret)
162 unregister_pernet_subsys(&ip6table_nat_net_ops);
163
164 return ret;
165 }
166
ip6table_nat_exit(void)167 static void __exit ip6table_nat_exit(void)
168 {
169 xt_unregister_template(&nf_nat_ipv6_table);
170 unregister_pernet_subsys(&ip6table_nat_net_ops);
171 }
172
173 module_init(ip6table_nat_init);
174 module_exit(ip6table_nat_exit);
175
176 MODULE_LICENSE("GPL");
177 MODULE_DESCRIPTION("Ip6tables legacy nat table");
178