1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x.
4  *
5  * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
6  * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
7  */
8 
9 #include <linux/module.h>
10 #include <linux/moduleparam.h>
11 #include <linux/netfilter_ipv6/ip6_tables.h>
12 #include <linux/slab.h>
13 
14 MODULE_LICENSE("GPL");
15 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
16 MODULE_DESCRIPTION("ip6tables filter table");
17 
18 #define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) | \
19 			    (1 << NF_INET_FORWARD) | \
20 			    (1 << NF_INET_LOCAL_OUT))
21 
22 static const struct xt_table packet_filter = {
23 	.name		= "filter",
24 	.valid_hooks	= FILTER_VALID_HOOKS,
25 	.me		= THIS_MODULE,
26 	.af		= NFPROTO_IPV6,
27 	.priority	= NF_IP6_PRI_FILTER,
28 };
29 
30 static struct nf_hook_ops *filter_ops __read_mostly;
31 
32 /* Default to forward because I got too much mail already. */
33 static bool forward = true;
34 module_param(forward, bool, 0000);
35 
ip6table_filter_table_init(struct net * net)36 static int ip6table_filter_table_init(struct net *net)
37 {
38 	struct ip6t_replace *repl;
39 	int err;
40 
41 	repl = ip6t_alloc_initial_table(&packet_filter);
42 	if (repl == NULL)
43 		return -ENOMEM;
44 	/* Entry 1 is the FORWARD hook */
45 	((struct ip6t_standard *)repl->entries)[1].target.verdict =
46 		forward ? -NF_ACCEPT - 1 : -NF_DROP - 1;
47 
48 	err = ip6t_register_table(net, &packet_filter, repl, filter_ops);
49 	kfree(repl);
50 	return err;
51 }
52 
ip6table_filter_net_init(struct net * net)53 static int __net_init ip6table_filter_net_init(struct net *net)
54 {
55 	if (!forward)
56 		return ip6table_filter_table_init(net);
57 
58 	return 0;
59 }
60 
ip6table_filter_net_pre_exit(struct net * net)61 static void __net_exit ip6table_filter_net_pre_exit(struct net *net)
62 {
63 	ip6t_unregister_table_pre_exit(net, "filter");
64 }
65 
ip6table_filter_net_exit(struct net * net)66 static void __net_exit ip6table_filter_net_exit(struct net *net)
67 {
68 	ip6t_unregister_table_exit(net, "filter");
69 }
70 
71 static struct pernet_operations ip6table_filter_net_ops = {
72 	.init = ip6table_filter_net_init,
73 	.pre_exit = ip6table_filter_net_pre_exit,
74 	.exit = ip6table_filter_net_exit,
75 };
76 
ip6table_filter_init(void)77 static int __init ip6table_filter_init(void)
78 {
79 	int ret = xt_register_template(&packet_filter,
80 					ip6table_filter_table_init);
81 
82 	if (ret < 0)
83 		return ret;
84 
85 	filter_ops = xt_hook_ops_alloc(&packet_filter, ip6t_do_table);
86 	if (IS_ERR(filter_ops)) {
87 		xt_unregister_template(&packet_filter);
88 		return PTR_ERR(filter_ops);
89 	}
90 
91 	ret = register_pernet_subsys(&ip6table_filter_net_ops);
92 	if (ret < 0) {
93 		xt_unregister_template(&packet_filter);
94 		kfree(filter_ops);
95 		return ret;
96 	}
97 
98 	return ret;
99 }
100 
ip6table_filter_fini(void)101 static void __exit ip6table_filter_fini(void)
102 {
103 	unregister_pernet_subsys(&ip6table_filter_net_ops);
104 	xt_unregister_template(&packet_filter);
105 	kfree(filter_ops);
106 }
107 
108 module_init(ip6table_filter_init);
109 module_exit(ip6table_filter_fini);
110