1 /*
2 * ebtable_filter
3 *
4 * Authors:
5 * Bart De Schuymer <bdschuym@pandora.be>
6 *
7 * April, 2002
8 *
9 */
10
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
17 static struct ebt_entries initial_chains[] =
18 {
19 {
20 .name = "INPUT",
21 .policy = EBT_ACCEPT,
22 },
23 {
24 .name = "FORWARD",
25 .policy = EBT_ACCEPT,
26 },
27 {
28 .name = "OUTPUT",
29 .policy = EBT_ACCEPT,
30 },
31 };
32
33 static struct ebt_replace_kernel initial_table =
34 {
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 {
55 .name = "filter",
56 .table = &initial_table,
57 .valid_hooks = FILTER_VALID_HOOKS,
58 .check = check,
59 .me = THIS_MODULE,
60 };
61
62 static unsigned int
ebt_in_hook(unsigned int hook,struct sk_buff * skb,const struct net_device * in,const struct net_device * out,int (* okfn)(struct sk_buff *))63 ebt_in_hook(unsigned int hook, struct sk_buff *skb, const struct net_device *in,
64 const struct net_device *out, int (*okfn)(struct sk_buff *))
65 {
66 return ebt_do_table(hook, skb, in, out, dev_net(in)->xt.frame_filter);
67 }
68
69 static unsigned int
ebt_out_hook(unsigned int hook,struct sk_buff * skb,const struct net_device * in,const struct net_device * out,int (* okfn)(struct sk_buff *))70 ebt_out_hook(unsigned int hook, struct sk_buff *skb, const struct net_device *in,
71 const struct net_device *out, int (*okfn)(struct sk_buff *))
72 {
73 return ebt_do_table(hook, skb, in, out, dev_net(out)->xt.frame_filter);
74 }
75
76 static struct nf_hook_ops ebt_ops_filter[] __read_mostly = {
77 {
78 .hook = ebt_in_hook,
79 .owner = THIS_MODULE,
80 .pf = NFPROTO_BRIDGE,
81 .hooknum = NF_BR_LOCAL_IN,
82 .priority = NF_BR_PRI_FILTER_BRIDGED,
83 },
84 {
85 .hook = ebt_in_hook,
86 .owner = THIS_MODULE,
87 .pf = NFPROTO_BRIDGE,
88 .hooknum = NF_BR_FORWARD,
89 .priority = NF_BR_PRI_FILTER_BRIDGED,
90 },
91 {
92 .hook = ebt_out_hook,
93 .owner = THIS_MODULE,
94 .pf = NFPROTO_BRIDGE,
95 .hooknum = NF_BR_LOCAL_OUT,
96 .priority = NF_BR_PRI_FILTER_OTHER,
97 },
98 };
99
frame_filter_net_init(struct net * net)100 static int __net_init frame_filter_net_init(struct net *net)
101 {
102 net->xt.frame_filter = ebt_register_table(net, &frame_filter);
103 if (IS_ERR(net->xt.frame_filter))
104 return PTR_ERR(net->xt.frame_filter);
105 return 0;
106 }
107
frame_filter_net_exit(struct net * net)108 static void __net_exit frame_filter_net_exit(struct net *net)
109 {
110 ebt_unregister_table(net, net->xt.frame_filter);
111 }
112
113 static struct pernet_operations frame_filter_net_ops = {
114 .init = frame_filter_net_init,
115 .exit = frame_filter_net_exit,
116 };
117
ebtable_filter_init(void)118 static int __init ebtable_filter_init(void)
119 {
120 int ret;
121
122 ret = register_pernet_subsys(&frame_filter_net_ops);
123 if (ret < 0)
124 return ret;
125 ret = nf_register_hooks(ebt_ops_filter, ARRAY_SIZE(ebt_ops_filter));
126 if (ret < 0)
127 unregister_pernet_subsys(&frame_filter_net_ops);
128 return ret;
129 }
130
ebtable_filter_fini(void)131 static void __exit ebtable_filter_fini(void)
132 {
133 nf_unregister_hooks(ebt_ops_filter, ARRAY_SIZE(ebt_ops_filter));
134 unregister_pernet_subsys(&frame_filter_net_ops);
135 }
136
137 module_init(ebtable_filter_init);
138 module_exit(ebtable_filter_fini);
139 MODULE_LICENSE("GPL");
140