This source file includes following definitions.
- check
- ebt_in_hook
- ebt_out_hook
- frame_filter_net_init
- frame_filter_net_exit
- ebtable_filter_init
- ebtable_filter_fini
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12 #include <linux/netfilter_bridge/ebtables.h>
13 #include <uapi/linux/netfilter_bridge.h>
14 #include <linux/module.h>
15
16 #define FILTER_VALID_HOOKS ((1 << NF_BR_LOCAL_IN) | (1 << NF_BR_FORWARD) | \
17 (1 << NF_BR_LOCAL_OUT))
18
19 static struct ebt_entries initial_chains[] = {
20 {
21 .name = "INPUT",
22 .policy = EBT_ACCEPT,
23 },
24 {
25 .name = "FORWARD",
26 .policy = EBT_ACCEPT,
27 },
28 {
29 .name = "OUTPUT",
30 .policy = EBT_ACCEPT,
31 },
32 };
33
34 static struct ebt_replace_kernel initial_table = {
35 .name = "filter",
36 .valid_hooks = FILTER_VALID_HOOKS,
37 .entries_size = 3 * sizeof(struct ebt_entries),
38 .hook_entry = {
39 [NF_BR_LOCAL_IN] = &initial_chains[0],
40 [NF_BR_FORWARD] = &initial_chains[1],
41 [NF_BR_LOCAL_OUT] = &initial_chains[2],
42 },
43 .entries = (char *)initial_chains,
44 };
45
46 static int check(const struct ebt_table_info *info, unsigned int valid_hooks)
47 {
48 if (valid_hooks & ~FILTER_VALID_HOOKS)
49 return -EINVAL;
50 return 0;
51 }
52
53 static const struct ebt_table frame_filter = {
54 .name = "filter",
55 .table = &initial_table,
56 .valid_hooks = FILTER_VALID_HOOKS,
57 .check = check,
58 .me = THIS_MODULE,
59 };
60
61 static unsigned int
62 ebt_in_hook(void *priv, struct sk_buff *skb,
63 const struct nf_hook_state *state)
64 {
65 return ebt_do_table(skb, state, state->net->xt.frame_filter);
66 }
67
68 static unsigned int
69 ebt_out_hook(void *priv, struct sk_buff *skb,
70 const struct nf_hook_state *state)
71 {
72 return ebt_do_table(skb, state, state->net->xt.frame_filter);
73 }
74
75 static const struct nf_hook_ops ebt_ops_filter[] = {
76 {
77 .hook = ebt_in_hook,
78 .pf = NFPROTO_BRIDGE,
79 .hooknum = NF_BR_LOCAL_IN,
80 .priority = NF_BR_PRI_FILTER_BRIDGED,
81 },
82 {
83 .hook = ebt_in_hook,
84 .pf = NFPROTO_BRIDGE,
85 .hooknum = NF_BR_FORWARD,
86 .priority = NF_BR_PRI_FILTER_BRIDGED,
87 },
88 {
89 .hook = ebt_out_hook,
90 .pf = NFPROTO_BRIDGE,
91 .hooknum = NF_BR_LOCAL_OUT,
92 .priority = NF_BR_PRI_FILTER_OTHER,
93 },
94 };
95
96 static int __net_init frame_filter_net_init(struct net *net)
97 {
98 return ebt_register_table(net, &frame_filter, ebt_ops_filter,
99 &net->xt.frame_filter);
100 }
101
102 static void __net_exit frame_filter_net_exit(struct net *net)
103 {
104 ebt_unregister_table(net, net->xt.frame_filter, ebt_ops_filter);
105 }
106
107 static struct pernet_operations frame_filter_net_ops = {
108 .init = frame_filter_net_init,
109 .exit = frame_filter_net_exit,
110 };
111
112 static int __init ebtable_filter_init(void)
113 {
114 return register_pernet_subsys(&frame_filter_net_ops);
115 }
116
117 static void __exit ebtable_filter_fini(void)
118 {
119 unregister_pernet_subsys(&frame_filter_net_ops);
120 }
121
122 module_init(ebtable_filter_init);
123 module_exit(ebtable_filter_fini);
124 MODULE_LICENSE("GPL");