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