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
14 MODULE_LICENSE("GPL");
15 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
16 MODULE_DESCRIPTION("arptables filter table");
17
18 #define FILTER_VALID_HOOKS ((1 << NF_ARP_IN) | (1 << NF_ARP_OUT) | \
19 (1 << NF_ARP_FORWARD))
20
21 static 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
29 static struct nf_hook_ops *arpfilter_ops __read_mostly;
30
31 static 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
44 static void __net_exit arptable_filter_net_pre_exit(struct net *net)
45 {
46 arpt_unregister_table_pre_exit(net, "filter");
47 }
48
49 static void __net_exit arptable_filter_net_exit(struct net *net)
50 {
51 arpt_unregister_table(net, "filter");
52 }
53
54 static struct pernet_operations arptable_filter_net_ops = {
55 .exit = arptable_filter_net_exit,
56 .pre_exit = arptable_filter_net_pre_exit,
57 };
58
59 static 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
83 static 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
90 module_init(arptable_filter_init);
91 module_exit(arptable_filter_fini);
92
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