1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * ebtable_filter
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 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 const struct ebt_table frame_filter = {
47 .name = "filter",
48 .table = &initial_table,
49 .valid_hooks = FILTER_VALID_HOOKS,
50 .me = THIS_MODULE,
51 };
52
53 static unsigned int
ebt_filter_hook(void * priv,struct sk_buff * skb,const struct nf_hook_state * state)54 ebt_filter_hook(void *priv, struct sk_buff *skb,
55 const struct nf_hook_state *state)
56 {
57 return ebt_do_table(skb, state, priv);
58 }
59
60 static const struct nf_hook_ops ebt_ops_filter[] = {
61 {
62 .hook = ebt_filter_hook,
63 .pf = NFPROTO_BRIDGE,
64 .hooknum = NF_BR_LOCAL_IN,
65 .priority = NF_BR_PRI_FILTER_BRIDGED,
66 },
67 {
68 .hook = ebt_filter_hook,
69 .pf = NFPROTO_BRIDGE,
70 .hooknum = NF_BR_FORWARD,
71 .priority = NF_BR_PRI_FILTER_BRIDGED,
72 },
73 {
74 .hook = ebt_filter_hook,
75 .pf = NFPROTO_BRIDGE,
76 .hooknum = NF_BR_LOCAL_OUT,
77 .priority = NF_BR_PRI_FILTER_OTHER,
78 },
79 };
80
frame_filter_table_init(struct net * net)81 static int frame_filter_table_init(struct net *net)
82 {
83 return ebt_register_table(net, &frame_filter, ebt_ops_filter);
84 }
85
frame_filter_net_pre_exit(struct net * net)86 static void __net_exit frame_filter_net_pre_exit(struct net *net)
87 {
88 ebt_unregister_table_pre_exit(net, "filter");
89 }
90
frame_filter_net_exit(struct net * net)91 static void __net_exit frame_filter_net_exit(struct net *net)
92 {
93 ebt_unregister_table(net, "filter");
94 }
95
96 static struct pernet_operations frame_filter_net_ops = {
97 .exit = frame_filter_net_exit,
98 .pre_exit = frame_filter_net_pre_exit,
99 };
100
ebtable_filter_init(void)101 static int __init ebtable_filter_init(void)
102 {
103 int ret = ebt_register_template(&frame_filter, frame_filter_table_init);
104
105 if (ret)
106 return ret;
107
108 ret = register_pernet_subsys(&frame_filter_net_ops);
109 if (ret) {
110 ebt_unregister_template(&frame_filter);
111 return ret;
112 }
113
114 return 0;
115 }
116
ebtable_filter_fini(void)117 static void __exit ebtable_filter_fini(void)
118 {
119 unregister_pernet_subsys(&frame_filter_net_ops);
120 ebt_unregister_template(&frame_filter);
121 }
122
123 module_init(ebtable_filter_init);
124 module_exit(ebtable_filter_fini);
125 MODULE_LICENSE("GPL");
126