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 #include <net/netfilter/nf_nat_core.h>
19 #include <net/netfilter/nf_nat_l3proto.h>
20
21 static int __net_init iptable_nat_table_init(struct net *net);
22
23 static const struct xt_table nf_nat_ipv4_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_IPV4,
31 .table_init = iptable_nat_table_init,
32 };
33
iptable_nat_do_chain(void * priv,struct sk_buff * skb,const struct nf_hook_state * state)34 static unsigned int iptable_nat_do_chain(void *priv,
35 struct sk_buff *skb,
36 const struct nf_hook_state *state)
37 {
38 return ipt_do_table(skb, state, state->net->ipv4.nat_table);
39 }
40
41 static const struct nf_hook_ops nf_nat_ipv4_ops[] = {
42 {
43 .hook = iptable_nat_do_chain,
44 .pf = NFPROTO_IPV4,
45 .hooknum = NF_INET_PRE_ROUTING,
46 .priority = NF_IP_PRI_NAT_DST,
47 },
48 {
49 .hook = iptable_nat_do_chain,
50 .pf = NFPROTO_IPV4,
51 .hooknum = NF_INET_POST_ROUTING,
52 .priority = NF_IP_PRI_NAT_SRC,
53 },
54 {
55 .hook = iptable_nat_do_chain,
56 .pf = NFPROTO_IPV4,
57 .hooknum = NF_INET_LOCAL_OUT,
58 .priority = NF_IP_PRI_NAT_DST,
59 },
60 {
61 .hook = iptable_nat_do_chain,
62 .pf = NFPROTO_IPV4,
63 .hooknum = NF_INET_LOCAL_IN,
64 .priority = NF_IP_PRI_NAT_SRC,
65 },
66 };
67
ipt_nat_register_lookups(struct net * net)68 static int ipt_nat_register_lookups(struct net *net)
69 {
70 int i, ret;
71
72 for (i = 0; i < ARRAY_SIZE(nf_nat_ipv4_ops); i++) {
73 ret = nf_nat_l3proto_ipv4_register_fn(net, &nf_nat_ipv4_ops[i]);
74 if (ret) {
75 while (i)
76 nf_nat_l3proto_ipv4_unregister_fn(net, &nf_nat_ipv4_ops[--i]);
77
78 return ret;
79 }
80 }
81
82 return 0;
83 }
84
ipt_nat_unregister_lookups(struct net * net)85 static void ipt_nat_unregister_lookups(struct net *net)
86 {
87 int i;
88
89 for (i = 0; i < ARRAY_SIZE(nf_nat_ipv4_ops); i++)
90 nf_nat_l3proto_ipv4_unregister_fn(net, &nf_nat_ipv4_ops[i]);
91 }
92
iptable_nat_table_init(struct net * net)93 static int __net_init iptable_nat_table_init(struct net *net)
94 {
95 struct ipt_replace *repl;
96 int ret;
97
98 if (net->ipv4.nat_table)
99 return 0;
100
101 repl = ipt_alloc_initial_table(&nf_nat_ipv4_table);
102 if (repl == NULL)
103 return -ENOMEM;
104 ret = ipt_register_table(net, &nf_nat_ipv4_table, repl,
105 NULL, &net->ipv4.nat_table);
106 if (ret < 0) {
107 kfree(repl);
108 return ret;
109 }
110
111 ret = ipt_nat_register_lookups(net);
112 if (ret < 0) {
113 ipt_unregister_table(net, net->ipv4.nat_table, NULL);
114 net->ipv4.nat_table = NULL;
115 }
116
117 kfree(repl);
118 return ret;
119 }
120
iptable_nat_net_exit(struct net * net)121 static void __net_exit iptable_nat_net_exit(struct net *net)
122 {
123 if (!net->ipv4.nat_table)
124 return;
125 ipt_nat_unregister_lookups(net);
126 ipt_unregister_table(net, net->ipv4.nat_table, NULL);
127 net->ipv4.nat_table = NULL;
128 }
129
130 static struct pernet_operations iptable_nat_net_ops = {
131 .exit = iptable_nat_net_exit,
132 };
133
iptable_nat_init(void)134 static int __init iptable_nat_init(void)
135 {
136 int ret = register_pernet_subsys(&iptable_nat_net_ops);
137
138 if (ret)
139 return ret;
140
141 ret = iptable_nat_table_init(&init_net);
142 if (ret)
143 unregister_pernet_subsys(&iptable_nat_net_ops);
144 return ret;
145 }
146
iptable_nat_exit(void)147 static void __exit iptable_nat_exit(void)
148 {
149 unregister_pernet_subsys(&iptable_nat_net_ops);
150 }
151
152 module_init(iptable_nat_init);
153 module_exit(iptable_nat_exit);
154
155 MODULE_LICENSE("GPL");
156
