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
check(const struct ebt_table_info * info,unsigned int valid_hooks)46 static int check(const struct ebt_table_info *info, unsigned int valid_hooks)
47 {
48 if (valid_hooks & ~NAT_VALID_HOOKS)
49 return -EINVAL;
50 return 0;
51 }
52
53 static const struct ebt_table frame_nat = {
54 .name = "nat",
55 .table = &initial_table,
56 .valid_hooks = NAT_VALID_HOOKS,
57 .check = check,
58 .me = THIS_MODULE,
59 };
60
61 static const struct nf_hook_ops ebt_ops_nat[] = {
62 {
63 .hook = ebt_do_table,
64 .pf = NFPROTO_BRIDGE,
65 .hooknum = NF_BR_LOCAL_OUT,
66 .priority = NF_BR_PRI_NAT_DST_OTHER,
67 },
68 {
69 .hook = ebt_do_table,
70 .pf = NFPROTO_BRIDGE,
71 .hooknum = NF_BR_POST_ROUTING,
72 .priority = NF_BR_PRI_NAT_SRC,
73 },
74 {
75 .hook = ebt_do_table,
76 .pf = NFPROTO_BRIDGE,
77 .hooknum = NF_BR_PRE_ROUTING,
78 .priority = NF_BR_PRI_NAT_DST_BRIDGED,
79 },
80 };
81
frame_nat_table_init(struct net * net)82 static int frame_nat_table_init(struct net *net)
83 {
84 return ebt_register_table(net, &frame_nat, ebt_ops_nat);
85 }
86
frame_nat_net_pre_exit(struct net * net)87 static void __net_exit frame_nat_net_pre_exit(struct net *net)
88 {
89 ebt_unregister_table_pre_exit(net, "nat");
90 }
91
frame_nat_net_exit(struct net * net)92 static void __net_exit frame_nat_net_exit(struct net *net)
93 {
94 ebt_unregister_table(net, "nat");
95 }
96
97 static struct pernet_operations frame_nat_net_ops = {
98 .exit = frame_nat_net_exit,
99 .pre_exit = frame_nat_net_pre_exit,
100 };
101
ebtable_nat_init(void)102 static int __init ebtable_nat_init(void)
103 {
104 int ret = ebt_register_template(&frame_nat, frame_nat_table_init);
105
106 if (ret)
107 return ret;
108
109 ret = register_pernet_subsys(&frame_nat_net_ops);
110 if (ret) {
111 ebt_unregister_template(&frame_nat);
112 return ret;
113 }
114
115 return ret;
116 }
117
ebtable_nat_fini(void)118 static void __exit ebtable_nat_fini(void)
119 {
120 unregister_pernet_subsys(&frame_nat_net_ops);
121 ebt_unregister_template(&frame_nat);
122 }
123
124 module_init(ebtable_nat_init);
125 module_exit(ebtable_nat_fini);
126 MODULE_LICENSE("GPL");
127