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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(const struct nf_hook_ops *ops, struct sk_buff *skb,
61 const struct net_device *in, const struct net_device *out,
62 int (*okfn)(struct sk_buff *))
63{
64 return ebt_do_table(ops->hooknum, skb, in, out,
65 dev_net(in)->xt.frame_filter);
66}
67
68static unsigned int
69ebt_out_hook(const struct nf_hook_ops *ops, struct sk_buff *skb,
70 const struct net_device *in, const struct net_device *out,
71 int (*okfn)(struct sk_buff *))
72{
73 return ebt_do_table(ops->hooknum, skb, in, out,
74 dev_net(out)->xt.frame_filter);
75}
76
77static struct nf_hook_ops ebt_ops_filter[] __read_mostly = {
78 {
79 .hook = ebt_in_hook,
80 .owner = THIS_MODULE,
81 .pf = NFPROTO_BRIDGE,
82 .hooknum = NF_BR_LOCAL_IN,
83 .priority = NF_BR_PRI_FILTER_BRIDGED,
84 },
85 {
86 .hook = ebt_in_hook,
87 .owner = THIS_MODULE,
88 .pf = NFPROTO_BRIDGE,
89 .hooknum = NF_BR_FORWARD,
90 .priority = NF_BR_PRI_FILTER_BRIDGED,
91 },
92 {
93 .hook = ebt_out_hook,
94 .owner = THIS_MODULE,
95 .pf = NFPROTO_BRIDGE,
96 .hooknum = NF_BR_LOCAL_OUT,
97 .priority = NF_BR_PRI_FILTER_OTHER,
98 },
99};
100
101static int __net_init frame_filter_net_init(struct net *net)
102{
103 net->xt.frame_filter = ebt_register_table(net, &frame_filter);
104 return PTR_ERR_OR_ZERO(net->xt.frame_filter);
105}
106
107static void __net_exit frame_filter_net_exit(struct net *net)
108{
109 ebt_unregister_table(net, net->xt.frame_filter);
110}
111
112static struct pernet_operations frame_filter_net_ops = {
113 .init = frame_filter_net_init,
114 .exit = frame_filter_net_exit,
115};
116
117static int __init ebtable_filter_init(void)
118{
119 int ret;
120
121 ret = register_pernet_subsys(&frame_filter_net_ops);
122 if (ret < 0)
123 return ret;
124 ret = nf_register_hooks(ebt_ops_filter, ARRAY_SIZE(ebt_ops_filter));
125 if (ret < 0)
126 unregister_pernet_subsys(&frame_filter_net_ops);
127 return ret;
128}
129
130static void __exit ebtable_filter_fini(void)
131{
132 nf_unregister_hooks(ebt_ops_filter, ARRAY_SIZE(ebt_ops_filter));
133 unregister_pernet_subsys(&frame_filter_net_ops);
134}
135
136module_init(ebtable_filter_init);
137module_exit(ebtable_filter_fini);
138MODULE_LICENSE("GPL");
139
