1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * ebtable_nat
4 *
5 * Authors:
6 * Bart De Schuymer <bdschuym@pandora.be>
7 *
8 * April, 2002
9 *
10 */
11
12 #include <linux/netfilter_bridge/ebtables.h>
13 #include <uapi/linux/netfilter_bridge.h>
14 #include <linux/module.h>
15
16 #define NAT_VALID_HOOKS ((1 << NF_BR_PRE_ROUTING) | (1 << NF_BR_LOCAL_OUT) | \
17 (1 << NF_BR_POST_ROUTING))
18
19 static struct ebt_entries initial_chains[] = {
20 {
21 .name = "PREROUTING",
22 .policy = EBT_ACCEPT,
23 },
24 {
25 .name = "OUTPUT",
26 .policy = EBT_ACCEPT,
27 },
28 {
29 .name = "POSTROUTING",
30 .policy = EBT_ACCEPT,
31 }
32 };
33
34 static struct ebt_replace_kernel initial_table = {
35 .name = "nat",
36 .valid_hooks = NAT_VALID_HOOKS,
37 .entries_size = 3 * sizeof(struct ebt_entries),
38 .hook_entry = {
39 [NF_BR_PRE_ROUTING] = &initial_chains[0],
40 [NF_BR_LOCAL_OUT] = &initial_chains[1],
41 [NF_BR_POST_ROUTING] = &initial_chains[2],
42 },
43 .entries = (char *)initial_chains,
44 };
45
46 static const struct ebt_table frame_nat = {
47 .name = "nat",
48 .table = &initial_table,
49 .valid_hooks = NAT_VALID_HOOKS,
50 .me = THIS_MODULE,
51 };
52
53 static const struct nf_hook_ops ebt_ops_nat[] = {
54 {
55 .hook = ebt_do_table,
56 .pf = NFPROTO_BRIDGE,
57 .hooknum = NF_BR_LOCAL_OUT,
58 .priority = NF_BR_PRI_NAT_DST_OTHER,
59 },
60 {
61 .hook = ebt_do_table,
62 .pf = NFPROTO_BRIDGE,
63 .hooknum = NF_BR_POST_ROUTING,
64 .priority = NF_BR_PRI_NAT_SRC,
65 },
66 {
67 .hook = ebt_do_table,
68 .pf = NFPROTO_BRIDGE,
69 .hooknum = NF_BR_PRE_ROUTING,
70 .priority = NF_BR_PRI_NAT_DST_BRIDGED,
71 },
72 };
73
frame_nat_table_init(struct net * net)74 static int frame_nat_table_init(struct net *net)
75 {
76 return ebt_register_table(net, &frame_nat, ebt_ops_nat);
77 }
78
frame_nat_net_pre_exit(struct net * net)79 static void __net_exit frame_nat_net_pre_exit(struct net *net)
80 {
81 ebt_unregister_table_pre_exit(net, "nat");
82 }
83
frame_nat_net_exit(struct net * net)84 static void __net_exit frame_nat_net_exit(struct net *net)
85 {
86 ebt_unregister_table(net, "nat");
87 }
88
89 static struct pernet_operations frame_nat_net_ops = {
90 .exit = frame_nat_net_exit,
91 .pre_exit = frame_nat_net_pre_exit,
92 };
93
ebtable_nat_init(void)94 static int __init ebtable_nat_init(void)
95 {
96 int ret = ebt_register_template(&frame_nat, frame_nat_table_init);
97
98 if (ret)
99 return ret;
100
101 ret = register_pernet_subsys(&frame_nat_net_ops);
102 if (ret) {
103 ebt_unregister_template(&frame_nat);
104 return ret;
105 }
106
107 return ret;
108 }
109
ebtable_nat_fini(void)110 static void __exit ebtable_nat_fini(void)
111 {
112 unregister_pernet_subsys(&frame_nat_net_ops);
113 ebt_unregister_template(&frame_nat);
114 }
115
116 module_init(ebtable_nat_init);
117 module_exit(ebtable_nat_fini);
118 MODULE_LICENSE("GPL");
119
