ip6table_filter.c revision 35aad0ffdf548617940ca1e78be1f2e0bafc4496 
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
16MODULE_LICENSE("GPL");
17MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
18MODULE_DESCRIPTION("ip6tables filter table");
19
20#define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) | \
21			    (1 << NF_INET_FORWARD) | \
22			    (1 << NF_INET_LOCAL_OUT))
23
24static struct
25{
26	struct ip6t_replace repl;
27	struct ip6t_standard entries[3];
28	struct ip6t_error term;
29} initial_table __net_initdata = {
30	.repl = {
31		.name = "filter",
32		.valid_hooks = FILTER_VALID_HOOKS,
33		.num_entries = 4,
34		.size = sizeof(struct ip6t_standard) * 3 + sizeof(struct ip6t_error),
35		.hook_entry = {
36			[NF_INET_LOCAL_IN] = 0,
37			[NF_INET_FORWARD] = sizeof(struct ip6t_standard),
38			[NF_INET_LOCAL_OUT] = sizeof(struct ip6t_standard) * 2
39		},
40		.underflow = {
41			[NF_INET_LOCAL_IN] = 0,
42			[NF_INET_FORWARD] = sizeof(struct ip6t_standard),
43			[NF_INET_LOCAL_OUT] = sizeof(struct ip6t_standard) * 2
44		},
45	},
46	.entries = {
47		IP6T_STANDARD_INIT(NF_ACCEPT),	/* LOCAL_IN */
48		IP6T_STANDARD_INIT(NF_ACCEPT),	/* FORWARD */
49		IP6T_STANDARD_INIT(NF_ACCEPT),	/* LOCAL_OUT */
50	},
51	.term = IP6T_ERROR_INIT,		/* ERROR */
52};
53
54static const struct xt_table packet_filter = {
55	.name		= "filter",
56	.valid_hooks	= FILTER_VALID_HOOKS,
57	.me		= THIS_MODULE,
58	.af		= NFPROTO_IPV6,
59};
60
61/* The work comes in here from netfilter.c. */
62static unsigned int
63ip6t_in_hook(unsigned int hook,
64		   struct sk_buff *skb,
65		   const struct net_device *in,
66		   const struct net_device *out,
67		   int (*okfn)(struct sk_buff *))
68{
69	return ip6t_do_table(skb, hook, in, out,
70			     dev_net(in)->ipv6.ip6table_filter);
71}
72
73static unsigned int
74ip6t_local_out_hook(unsigned int hook,
75		   struct sk_buff *skb,
76		   const struct net_device *in,
77		   const struct net_device *out,
78		   int (*okfn)(struct sk_buff *))
79{
80#if 0
81	/* root is playing with raw sockets. */
82	if (skb->len < sizeof(struct iphdr)
83	    || ip_hdrlen(skb) < sizeof(struct iphdr)) {
84		if (net_ratelimit())
85			printk("ip6t_hook: happy cracking.\n");
86		return NF_ACCEPT;
87	}
88#endif
89
90	return ip6t_do_table(skb, hook, in, out,
91			     dev_net(out)->ipv6.ip6table_filter);
92}
93
94static struct nf_hook_ops ip6t_ops[] __read_mostly = {
95	{
96		.hook		= ip6t_in_hook,
97		.owner		= THIS_MODULE,
98		.pf		= NFPROTO_IPV6,
99		.hooknum	= NF_INET_LOCAL_IN,
100		.priority	= NF_IP6_PRI_FILTER,
101	},
102	{
103		.hook		= ip6t_in_hook,
104		.owner		= THIS_MODULE,
105		.pf		= NFPROTO_IPV6,
106		.hooknum	= NF_INET_FORWARD,
107		.priority	= NF_IP6_PRI_FILTER,
108	},
109	{
110		.hook		= ip6t_local_out_hook,
111		.owner		= THIS_MODULE,
112		.pf		= NFPROTO_IPV6,
113		.hooknum	= NF_INET_LOCAL_OUT,
114		.priority	= NF_IP6_PRI_FILTER,
115	},
116};
117
118/* Default to forward because I got too much mail already. */
119static int forward = NF_ACCEPT;
120module_param(forward, bool, 0000);
121
122static int __net_init ip6table_filter_net_init(struct net *net)
123{
124	/* Register table */
125	net->ipv6.ip6table_filter =
126		ip6t_register_table(net, &packet_filter, &initial_table.repl);
127	if (IS_ERR(net->ipv6.ip6table_filter))
128		return PTR_ERR(net->ipv6.ip6table_filter);
129	return 0;
130}
131
132static void __net_exit ip6table_filter_net_exit(struct net *net)
133{
134	ip6t_unregister_table(net->ipv6.ip6table_filter);
135}
136
137static struct pernet_operations ip6table_filter_net_ops = {
138	.init = ip6table_filter_net_init,
139	.exit = ip6table_filter_net_exit,
140};
141
142static int __init ip6table_filter_init(void)
143{
144	int ret;
145
146	if (forward < 0 || forward > NF_MAX_VERDICT) {
147		printk("iptables forward must be 0 or 1\n");
148		return -EINVAL;
149	}
150
151	/* Entry 1 is the FORWARD hook */
152	initial_table.entries[1].target.verdict = -forward - 1;
153
154	ret = register_pernet_subsys(&ip6table_filter_net_ops);
155	if (ret < 0)
156		return ret;
157
158	/* Register hooks */
159	ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
160	if (ret < 0)
161		goto cleanup_table;
162
163	return ret;
164
165 cleanup_table:
166	unregister_pernet_subsys(&ip6table_filter_net_ops);
167	return ret;
168}
169
170static void __exit ip6table_filter_fini(void)
171{
172	nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
173	unregister_pernet_subsys(&ip6table_filter_net_ops);
174}
175
176module_init(ip6table_filter_init);
177module_exit(ip6table_filter_fini);
178