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11#include <linux/netfilter_bridge/ebtables.h>
12#include <linux/module.h>
13
14#define NAT_VALID_HOOKS ((1 << NF_BR_PRE_ROUTING) | (1 << NF_BR_LOCAL_OUT) | \
15 (1 << NF_BR_POST_ROUTING))
16
17static struct ebt_entries initial_chains[] = {
18 {
19 .name = "PREROUTING",
20 .policy = EBT_ACCEPT,
21 },
22 {
23 .name = "OUTPUT",
24 .policy = EBT_ACCEPT,
25 },
26 {
27 .name = "POSTROUTING",
28 .policy = EBT_ACCEPT,
29 }
30};
31
32static struct ebt_replace_kernel initial_table = {
33 .name = "nat",
34 .valid_hooks = NAT_VALID_HOOKS,
35 .entries_size = 3 * sizeof(struct ebt_entries),
36 .hook_entry = {
37 [NF_BR_PRE_ROUTING] = &initial_chains[0],
38 [NF_BR_LOCAL_OUT] = &initial_chains[1],
39 [NF_BR_POST_ROUTING] = &initial_chains[2],
40 },
41 .entries = (char *)initial_chains,
42};
43
44static int check(const struct ebt_table_info *info, unsigned int valid_hooks)
45{
46 if (valid_hooks & ~NAT_VALID_HOOKS)
47 return -EINVAL;
48 return 0;
49}
50
51static struct ebt_table frame_nat = {
52 .name = "nat",
53 .table = &initial_table,
54 .valid_hooks = NAT_VALID_HOOKS,
55 .check = check,
56 .me = THIS_MODULE,
57};
58
59static unsigned int
60ebt_nat_in(const struct nf_hook_ops *ops, struct sk_buff *skb,
61 const struct nf_hook_state *state)
62{
63 return ebt_do_table(ops->hooknum, skb, state->in, state->out,
64 dev_net(state->in)->xt.frame_nat);
65}
66
67static unsigned int
68ebt_nat_out(const struct nf_hook_ops *ops, struct sk_buff *skb,
69 const struct nf_hook_state *state)
70{
71 return ebt_do_table(ops->hooknum, skb, state->in, state->out,
72 dev_net(state->out)->xt.frame_nat);
73}
74
75static struct nf_hook_ops ebt_ops_nat[] __read_mostly = {
76 {
77 .hook = ebt_nat_out,
78 .owner = THIS_MODULE,
79 .pf = NFPROTO_BRIDGE,
80 .hooknum = NF_BR_LOCAL_OUT,
81 .priority = NF_BR_PRI_NAT_DST_OTHER,
82 },
83 {
84 .hook = ebt_nat_out,
85 .owner = THIS_MODULE,
86 .pf = NFPROTO_BRIDGE,
87 .hooknum = NF_BR_POST_ROUTING,
88 .priority = NF_BR_PRI_NAT_SRC,
89 },
90 {
91 .hook = ebt_nat_in,
92 .owner = THIS_MODULE,
93 .pf = NFPROTO_BRIDGE,
94 .hooknum = NF_BR_PRE_ROUTING,
95 .priority = NF_BR_PRI_NAT_DST_BRIDGED,
96 },
97};
98
99static int __net_init frame_nat_net_init(struct net *net)
100{
101 net->xt.frame_nat = ebt_register_table(net, &frame_nat);
102 return PTR_ERR_OR_ZERO(net->xt.frame_nat);
103}
104
105static void __net_exit frame_nat_net_exit(struct net *net)
106{
107 ebt_unregister_table(net, net->xt.frame_nat);
108}
109
110static struct pernet_operations frame_nat_net_ops = {
111 .init = frame_nat_net_init,
112 .exit = frame_nat_net_exit,
113};
114
115static int __init ebtable_nat_init(void)
116{
117 int ret;
118
119 ret = register_pernet_subsys(&frame_nat_net_ops);
120 if (ret < 0)
121 return ret;
122 ret = nf_register_hooks(ebt_ops_nat, ARRAY_SIZE(ebt_ops_nat));
123 if (ret < 0)
124 unregister_pernet_subsys(&frame_nat_net_ops);
125 return ret;
126}
127
128static void __exit ebtable_nat_fini(void)
129{
130 nf_unregister_hooks(ebt_ops_nat, ARRAY_SIZE(ebt_ops_nat));
131 unregister_pernet_subsys(&frame_nat_net_ops);
132}
133
134module_init(ebtable_nat_init);
135module_exit(ebtable_nat_fini);
136MODULE_LICENSE("GPL");
137
