1/*
2 * Filtering ARP tables module.
3 *
4 * Copyright (C) 2002 David S. Miller (davem@redhat.com)
5 *
6 */
7
8#include <linux/module.h>
9#include <linux/netfilter/x_tables.h>
10#include <linux/netfilter_arp/arp_tables.h>
11#include <linux/slab.h>
12
13MODULE_LICENSE("GPL");
14MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
15MODULE_DESCRIPTION("arptables filter table");
16
17#define FILTER_VALID_HOOKS ((1 << NF_ARP_IN) | (1 << NF_ARP_OUT) | \
18			   (1 << NF_ARP_FORWARD))
19
20static const struct xt_table packet_filter = {
21	.name		= "filter",
22	.valid_hooks	= FILTER_VALID_HOOKS,
23	.me		= THIS_MODULE,
24	.af		= NFPROTO_ARP,
25	.priority	= NF_IP_PRI_FILTER,
26};
27
28/* The work comes in here from netfilter.c */
29static unsigned int
30arptable_filter_hook(const struct nf_hook_ops *ops, struct sk_buff *skb,
31		     const struct nf_hook_state *state)
32{
33	const struct net *net = dev_net(state->in ? state->in : state->out);
34
35	return arpt_do_table(skb, ops->hooknum, state,
36			     net->ipv4.arptable_filter);
37}
38
39static struct nf_hook_ops *arpfilter_ops __read_mostly;
40
41static int __net_init arptable_filter_net_init(struct net *net)
42{
43	struct arpt_replace *repl;
44
45	repl = arpt_alloc_initial_table(&packet_filter);
46	if (repl == NULL)
47		return -ENOMEM;
48	net->ipv4.arptable_filter =
49		arpt_register_table(net, &packet_filter, repl);
50	kfree(repl);
51	return PTR_ERR_OR_ZERO(net->ipv4.arptable_filter);
52}
53
54static void __net_exit arptable_filter_net_exit(struct net *net)
55{
56	arpt_unregister_table(net->ipv4.arptable_filter);
57}
58
59static struct pernet_operations arptable_filter_net_ops = {
60	.init = arptable_filter_net_init,
61	.exit = arptable_filter_net_exit,
62};
63
64static int __init arptable_filter_init(void)
65{
66	int ret;
67
68	ret = register_pernet_subsys(&arptable_filter_net_ops);
69	if (ret < 0)
70		return ret;
71
72	arpfilter_ops = xt_hook_link(&packet_filter, arptable_filter_hook);
73	if (IS_ERR(arpfilter_ops)) {
74		ret = PTR_ERR(arpfilter_ops);
75		goto cleanup_table;
76	}
77	return ret;
78
79cleanup_table:
80	unregister_pernet_subsys(&arptable_filter_net_ops);
81	return ret;
82}
83
84static void __exit arptable_filter_fini(void)
85{
86	xt_hook_unlink(&packet_filter, arpfilter_ops);
87	unregister_pernet_subsys(&arptable_filter_net_ops);
88}
89
90module_init(arptable_filter_init);
91module_exit(arptable_filter_fini);
92