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11#include <linux/netfilter_bridge/ebtables.h>
12#include <linux/module.h>
13
14#define FILTER_VALID_HOOKS ((1 << NF_BR_LOCAL_IN) | (1 << NF_BR_FORWARD) | \
15 (1 << NF_BR_LOCAL_OUT))
16
17static struct ebt_entries initial_chains[] = {
18 {
19 .name = "INPUT",
20 .policy = EBT_ACCEPT,
21 },
22 {
23 .name = "FORWARD",
24 .policy = EBT_ACCEPT,
25 },
26 {
27 .name = "OUTPUT",
28 .policy = EBT_ACCEPT,
29 },
30};
31
32static struct ebt_replace_kernel initial_table = {
33 .name = "filter",
34 .valid_hooks = FILTER_VALID_HOOKS,
35 .entries_size = 3 * sizeof(struct ebt_entries),
36 .hook_entry = {
37 [NF_BR_LOCAL_IN] = &initial_chains[0],
38 [NF_BR_FORWARD] = &initial_chains[1],
39 [NF_BR_LOCAL_OUT] = &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 & ~FILTER_VALID_HOOKS)
47 return -EINVAL;
48 return 0;
49}
50
51static const struct ebt_table frame_filter = {
52 .name = "filter",
53 .table = &initial_table,
54 .valid_hooks = FILTER_VALID_HOOKS,
55 .check = check,
56 .me = THIS_MODULE,
57};
58
59static unsigned int
60ebt_in_hook(void *priv, struct sk_buff *skb,
61 const struct nf_hook_state *state)
62{
63 return ebt_do_table(skb, state, state->net->xt.frame_filter);
64}
65
66static unsigned int
67ebt_out_hook(void *priv, struct sk_buff *skb,
68 const struct nf_hook_state *state)
69{
70 return ebt_do_table(skb, state, state->net->xt.frame_filter);
71}
72
73static struct nf_hook_ops ebt_ops_filter[] __read_mostly = {
74 {
75 .hook = ebt_in_hook,
76 .pf = NFPROTO_BRIDGE,
77 .hooknum = NF_BR_LOCAL_IN,
78 .priority = NF_BR_PRI_FILTER_BRIDGED,
79 },
80 {
81 .hook = ebt_in_hook,
82 .pf = NFPROTO_BRIDGE,
83 .hooknum = NF_BR_FORWARD,
84 .priority = NF_BR_PRI_FILTER_BRIDGED,
85 },
86 {
87 .hook = ebt_out_hook,
88 .pf = NFPROTO_BRIDGE,
89 .hooknum = NF_BR_LOCAL_OUT,
90 .priority = NF_BR_PRI_FILTER_OTHER,
91 },
92};
93
94static int __net_init frame_filter_net_init(struct net *net)
95{
96 net->xt.frame_filter = ebt_register_table(net, &frame_filter);
97 return PTR_ERR_OR_ZERO(net->xt.frame_filter);
98}
99
100static void __net_exit frame_filter_net_exit(struct net *net)
101{
102 ebt_unregister_table(net, net->xt.frame_filter);
103}
104
105static struct pernet_operations frame_filter_net_ops = {
106 .init = frame_filter_net_init,
107 .exit = frame_filter_net_exit,
108};
109
110static int __init ebtable_filter_init(void)
111{
112 int ret;
113
114 ret = register_pernet_subsys(&frame_filter_net_ops);
115 if (ret < 0)
116 return ret;
117 ret = nf_register_hooks(ebt_ops_filter, ARRAY_SIZE(ebt_ops_filter));
118 if (ret < 0)
119 unregister_pernet_subsys(&frame_filter_net_ops);
120 return ret;
121}
122
123static void __exit ebtable_filter_fini(void)
124{
125 nf_unregister_hooks(ebt_ops_filter, ARRAY_SIZE(ebt_ops_filter));
126 unregister_pernet_subsys(&frame_filter_net_ops);
127}
128
129module_init(ebtable_filter_init);
130module_exit(ebtable_filter_fini);
131MODULE_LICENSE("GPL");
132
