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
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 & ~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
ebt_filter_hook(void * priv,struct sk_buff * skb,const struct nf_hook_state * state)62 ebt_filter_hook(void *priv, struct sk_buff *skb,
63 const struct nf_hook_state *state)
64 {
65 return ebt_do_table(skb, state, priv);
66 }
67
68 static const struct nf_hook_ops ebt_ops_filter[] = {
69 {
70 .hook = ebt_filter_hook,
71 .pf = NFPROTO_BRIDGE,
72 .hooknum = NF_BR_LOCAL_IN,
73 .priority = NF_BR_PRI_FILTER_BRIDGED,
74 },
75 {
76 .hook = ebt_filter_hook,
77 .pf = NFPROTO_BRIDGE,
78 .hooknum = NF_BR_FORWARD,
79 .priority = NF_BR_PRI_FILTER_BRIDGED,
80 },
81 {
82 .hook = ebt_filter_hook,
83 .pf = NFPROTO_BRIDGE,
84 .hooknum = NF_BR_LOCAL_OUT,
85 .priority = NF_BR_PRI_FILTER_OTHER,
86 },
87 };
88
frame_filter_table_init(struct net * net)89 static int frame_filter_table_init(struct net *net)
90 {
91 return ebt_register_table(net, &frame_filter, ebt_ops_filter);
92 }
93
frame_filter_net_pre_exit(struct net * net)94 static void __net_exit frame_filter_net_pre_exit(struct net *net)
95 {
96 ebt_unregister_table_pre_exit(net, "filter");
97 }
98
frame_filter_net_exit(struct net * net)99 static void __net_exit frame_filter_net_exit(struct net *net)
100 {
101 ebt_unregister_table(net, "filter");
102 }
103
104 static struct pernet_operations frame_filter_net_ops = {
105 .exit = frame_filter_net_exit,
106 .pre_exit = frame_filter_net_pre_exit,
107 };
108
ebtable_filter_init(void)109 static int __init ebtable_filter_init(void)
110 {
111 int ret = ebt_register_template(&frame_filter, frame_filter_table_init);
112
113 if (ret)
114 return ret;
115
116 ret = register_pernet_subsys(&frame_filter_net_ops);
117 if (ret) {
118 ebt_unregister_template(&frame_filter);
119 return ret;
120 }
121
122 return 0;
123 }
124
ebtable_filter_fini(void)125 static void __exit ebtable_filter_fini(void)
126 {
127 unregister_pernet_subsys(&frame_filter_net_ops);
128 ebt_unregister_template(&frame_filter);
129 }
130
131 module_init(ebtable_filter_init);
132 module_exit(ebtable_filter_fini);
133 MODULE_LICENSE("GPL");
134
