1 /*
2  * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x.
3  *
4  * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
5  * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11 
12 #include <linux/module.h>
13 #include <linux/moduleparam.h>
14 #include <linux/netfilter_ipv6/ip6_tables.h>
15 #include <linux/slab.h>
16 
17 MODULE_LICENSE("GPL");
18 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
19 MODULE_DESCRIPTION("ip6tables filter table");
20 
21 #define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) | \
22 			    (1 << NF_INET_FORWARD) | \
23 			    (1 << NF_INET_LOCAL_OUT))
24 
25 static const struct xt_table packet_filter = {
26 	.name		= "filter",
27 	.valid_hooks	= FILTER_VALID_HOOKS,
28 	.me		= THIS_MODULE,
29 	.af		= NFPROTO_IPV6,
30 	.priority	= NF_IP6_PRI_FILTER,
31 };
32 
33 /* The work comes in here from netfilter.c. */
34 static unsigned int
35 ip6table_filter_hook(void *priv, struct sk_buff *skb,
36 		     const struct nf_hook_state *state)
37 {
38 	return ip6t_do_table(skb, state, state->net->ipv6.ip6table_filter);
39 }
40 
41 static struct nf_hook_ops *filter_ops __read_mostly;
42 
43 /* Default to forward because I got too much mail already. */
44 static bool forward = true;
45 module_param(forward, bool, 0000);
46 
47 static int __net_init ip6table_filter_net_init(struct net *net)
48 {
49 	struct ip6t_replace *repl;
50 
51 	repl = ip6t_alloc_initial_table(&packet_filter);
52 	if (repl == NULL)
53 		return -ENOMEM;
54 	/* Entry 1 is the FORWARD hook */
55 	((struct ip6t_standard *)repl->entries)[1].target.verdict =
56 		forward ? -NF_ACCEPT - 1 : -NF_DROP - 1;
57 
58 	net->ipv6.ip6table_filter =
59 		ip6t_register_table(net, &packet_filter, repl);
60 	kfree(repl);
61 	return PTR_ERR_OR_ZERO(net->ipv6.ip6table_filter);
62 }
63 
64 static void __net_exit ip6table_filter_net_exit(struct net *net)
65 {
66 	ip6t_unregister_table(net, net->ipv6.ip6table_filter);
67 }
68 
69 static struct pernet_operations ip6table_filter_net_ops = {
70 	.init = ip6table_filter_net_init,
71 	.exit = ip6table_filter_net_exit,
72 };
73 
74 static int __init ip6table_filter_init(void)
75 {
76 	int ret;
77 
78 	ret = register_pernet_subsys(&ip6table_filter_net_ops);
79 	if (ret < 0)
80 		return ret;
81 
82 	/* Register hooks */
83 	filter_ops = xt_hook_link(&packet_filter, ip6table_filter_hook);
84 	if (IS_ERR(filter_ops)) {
85 		ret = PTR_ERR(filter_ops);
86 		goto cleanup_table;
87 	}
88 
89 	return ret;
90 
91  cleanup_table:
92 	unregister_pernet_subsys(&ip6table_filter_net_ops);
93 	return ret;
94 }
95 
96 static void __exit ip6table_filter_fini(void)
97 {
98 	xt_hook_unlink(&packet_filter, filter_ops);
99 	unregister_pernet_subsys(&ip6table_filter_net_ops);
100 }
101 
102 module_init(ip6table_filter_init);
103 module_exit(ip6table_filter_fini);
104