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 unsigned int
ebt_nat_in(void * priv,struct sk_buff * skb,const struct nf_hook_state * state)54 ebt_nat_in(void *priv, struct sk_buff *skb,
55 const struct nf_hook_state *state)
56 {
57 return ebt_do_table(skb, state, state->net->xt.frame_nat);
58 }
59
60 static unsigned int
ebt_nat_out(void * priv,struct sk_buff * skb,const struct nf_hook_state * state)61 ebt_nat_out(void *priv, struct sk_buff *skb,
62 const struct nf_hook_state *state)
63 {
64 return ebt_do_table(skb, state, state->net->xt.frame_nat);
65 }
66
67 static const struct nf_hook_ops ebt_ops_nat[] = {
68 {
69 .hook = ebt_nat_out,
70 .pf = NFPROTO_BRIDGE,
71 .hooknum = NF_BR_LOCAL_OUT,
72 .priority = NF_BR_PRI_NAT_DST_OTHER,
73 },
74 {
75 .hook = ebt_nat_out,
76 .pf = NFPROTO_BRIDGE,
77 .hooknum = NF_BR_POST_ROUTING,
78 .priority = NF_BR_PRI_NAT_SRC,
79 },
80 {
81 .hook = ebt_nat_in,
82 .pf = NFPROTO_BRIDGE,
83 .hooknum = NF_BR_PRE_ROUTING,
84 .priority = NF_BR_PRI_NAT_DST_BRIDGED,
85 },
86 };
87
frame_nat_net_init(struct net * net)88 static int __net_init frame_nat_net_init(struct net *net)
89 {
90 return ebt_register_table(net, &frame_nat, ebt_ops_nat,
91 &net->xt.frame_nat);
92 }
93
frame_nat_net_pre_exit(struct net * net)94 static void __net_exit frame_nat_net_pre_exit(struct net *net)
95 {
96 ebt_unregister_table_pre_exit(net, "nat", ebt_ops_nat);
97 }
98
frame_nat_net_exit(struct net * net)99 static void __net_exit frame_nat_net_exit(struct net *net)
100 {
101 ebt_unregister_table(net, net->xt.frame_nat);
102 }
103
104 static struct pernet_operations frame_nat_net_ops = {
105 .init = frame_nat_net_init,
106 .exit = frame_nat_net_exit,
107 .pre_exit = frame_nat_net_pre_exit,
108 };
109
ebtable_nat_init(void)110 static int __init ebtable_nat_init(void)
111 {
112 return register_pernet_subsys(&frame_nat_net_ops);
113 }
114
ebtable_nat_fini(void)115 static void __exit ebtable_nat_fini(void)
116 {
117 unregister_pernet_subsys(&frame_nat_net_ops);
118 }
119
120 module_init(ebtable_nat_init);
121 module_exit(ebtable_nat_fini);
122 MODULE_LICENSE("GPL");
123