1/* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
3 * (C) 2011 Patrick McHardy <kaber@trash.net>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 */
9
10#include <linux/module.h>
11#include <linux/netfilter.h>
12#include <linux/netfilter_ipv4.h>
13#include <linux/netfilter_ipv4/ip_tables.h>
14#include <linux/ip.h>
15#include <net/ip.h>
16
17#include <net/netfilter/nf_nat.h>
18
19static int __net_init iptable_nat_table_init(struct net *net);
20
21static const struct xt_table nf_nat_ipv4_table = {
22 .name = "nat",
23 .valid_hooks = (1 << NF_INET_PRE_ROUTING) |
24 (1 << NF_INET_POST_ROUTING) |
25 (1 << NF_INET_LOCAL_OUT) |
26 (1 << NF_INET_LOCAL_IN),
27 .me = THIS_MODULE,
28 .af = NFPROTO_IPV4,
29 .table_init = iptable_nat_table_init,
30};
31
32static unsigned int iptable_nat_do_chain(void *priv,
33 struct sk_buff *skb,
34 const struct nf_hook_state *state)
35{
36 return ipt_do_table(skb, state, state->net->ipv4.nat_table);
37}
38
39static const struct nf_hook_ops nf_nat_ipv4_ops[] = {
40 {
41 .hook = iptable_nat_do_chain,
42 .pf = NFPROTO_IPV4,
43 .hooknum = NF_INET_PRE_ROUTING,
44 .priority = NF_IP_PRI_NAT_DST,
45 },
46 {
47 .hook = iptable_nat_do_chain,
48 .pf = NFPROTO_IPV4,
49 .hooknum = NF_INET_POST_ROUTING,
50 .priority = NF_IP_PRI_NAT_SRC,
51 },
52 {
53 .hook = iptable_nat_do_chain,
54 .pf = NFPROTO_IPV4,
55 .hooknum = NF_INET_LOCAL_OUT,
56 .priority = NF_IP_PRI_NAT_DST,
57 },
58 {
59 .hook = iptable_nat_do_chain,
60 .pf = NFPROTO_IPV4,
61 .hooknum = NF_INET_LOCAL_IN,
62 .priority = NF_IP_PRI_NAT_SRC,
63 },
64};
65
66static int ipt_nat_register_lookups(struct net *net)
67{
68 int i, ret;
69
70 for (i = 0; i < ARRAY_SIZE(nf_nat_ipv4_ops); i++) {
71 ret = nf_nat_ipv4_register_fn(net, &nf_nat_ipv4_ops[i]);
72 if (ret) {
73 while (i)
74 nf_nat_ipv4_unregister_fn(net, &nf_nat_ipv4_ops[--i]);
75
76 return ret;
77 }
78 }
79
80 return 0;
81}
82
83static void ipt_nat_unregister_lookups(struct net *net)
84{
85 int i;
86
87 for (i = 0; i < ARRAY_SIZE(nf_nat_ipv4_ops); i++)
88 nf_nat_ipv4_unregister_fn(net, &nf_nat_ipv4_ops[i]);
89}
90
91static int __net_init iptable_nat_table_init(struct net *net)
92{
93 struct ipt_replace *repl;
94 int ret;
95
96 if (net->ipv4.nat_table)
97 return 0;
98
99 repl = ipt_alloc_initial_table(&nf_nat_ipv4_table);
100 if (repl == NULL)
101 return -ENOMEM;
102 ret = ipt_register_table(net, &nf_nat_ipv4_table, repl,
103 NULL, &net->ipv4.nat_table);
104 if (ret < 0) {
105 kfree(repl);
106 return ret;
107 }
108
109 ret = ipt_nat_register_lookups(net);
110 if (ret < 0) {
111 ipt_unregister_table(net, net->ipv4.nat_table, NULL);
112 net->ipv4.nat_table = NULL;
113 }
114
115 kfree(repl);
116 return ret;
117}
118
119static void __net_exit iptable_nat_net_exit(struct net *net)
120{
121 if (!net->ipv4.nat_table)
122 return;
123 ipt_nat_unregister_lookups(net);
124 ipt_unregister_table(net, net->ipv4.nat_table, NULL);
125 net->ipv4.nat_table = NULL;
126}
127
128static struct pernet_operations iptable_nat_net_ops = {
129 .exit = iptable_nat_net_exit,
130};
131
132static int __init iptable_nat_init(void)
133{
134 int ret = register_pernet_subsys(&iptable_nat_net_ops);
135
136 if (ret)
137 return ret;
138
139 ret = iptable_nat_table_init(&init_net);
140 if (ret)
141 unregister_pernet_subsys(&iptable_nat_net_ops);
142 return ret;
143}
144
145static void __exit iptable_nat_exit(void)
146{
147 unregister_pernet_subsys(&iptable_nat_net_ops);
148}
149
150module_init(iptable_nat_init);
151module_exit(iptable_nat_exit);
152
153MODULE_LICENSE("GPL");
154