1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Filtering ARP tables module.
4 *
5 * Copyright (C) 2002 David S. Miller (davem@redhat.com)
6 *
7 */
8
9#include <linux/module.h>
10#include <linux/netfilter/x_tables.h>
11#include <linux/netfilter_arp/arp_tables.h>
12#include <linux/slab.h>
13
14MODULE_LICENSE("GPL");
15MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
16MODULE_DESCRIPTION("arptables filter table");
17
18#define FILTER_VALID_HOOKS ((1 << NF_ARP_IN) | (1 << NF_ARP_OUT) | \
19			   (1 << NF_ARP_FORWARD))
20
21static const struct xt_table packet_filter = {
22	.name		= "filter",
23	.valid_hooks	= FILTER_VALID_HOOKS,
24	.me		= THIS_MODULE,
25	.af		= NFPROTO_ARP,
26	.priority	= NF_IP_PRI_FILTER,
27};
28
29static struct nf_hook_ops *arpfilter_ops __read_mostly;
30
31static int arptable_filter_table_init(struct net *net)
32{
33	struct arpt_replace *repl;
34	int err;
35
36	repl = arpt_alloc_initial_table(&packet_filter);
37	if (repl == NULL)
38		return -ENOMEM;
39	err = arpt_register_table(net, &packet_filter, repl, arpfilter_ops);
40	kfree(repl);
41	return err;
42}
43
44static void __net_exit arptable_filter_net_pre_exit(struct net *net)
45{
46	arpt_unregister_table_pre_exit(net, "filter");
47}
48
49static void __net_exit arptable_filter_net_exit(struct net *net)
50{
51	arpt_unregister_table(net, "filter");
52}
53
54static struct pernet_operations arptable_filter_net_ops = {
55	.exit = arptable_filter_net_exit,
56	.pre_exit = arptable_filter_net_pre_exit,
57};
58
59static int __init arptable_filter_init(void)
60{
61	int ret = xt_register_template(&packet_filter,
62				       arptable_filter_table_init);
63
64	if (ret < 0)
65		return ret;
66
67	arpfilter_ops = xt_hook_ops_alloc(&packet_filter, arpt_do_table);
68	if (IS_ERR(arpfilter_ops)) {
69		xt_unregister_template(&packet_filter);
70		return PTR_ERR(arpfilter_ops);
71	}
72
73	ret = register_pernet_subsys(&arptable_filter_net_ops);
74	if (ret < 0) {
75		xt_unregister_template(&packet_filter);
76		kfree(arpfilter_ops);
77		return ret;
78	}
79
80	return ret;
81}
82
83static void __exit arptable_filter_fini(void)
84{
85	unregister_pernet_subsys(&arptable_filter_net_ops);
86	xt_unregister_template(&packet_filter);
87	kfree(arpfilter_ops);
88}
89
90module_init(arptable_filter_init);
91module_exit(arptable_filter_fini);
92