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