ip6table_filter.c revision 6e23ae2a48750bda407a4a58f52a4865d7308bf5 
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 __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 struct xt_table packet_filter = {
55	.name		= "filter",
56	.valid_hooks	= FILTER_VALID_HOOKS,
57	.lock		= RW_LOCK_UNLOCKED,
58	.me		= THIS_MODULE,
59	.af		= AF_INET6,
60};
61
62/* The work comes in here from netfilter.c. */
63static unsigned int
64ip6t_hook(unsigned int hook,
65	 struct sk_buff *skb,
66	 const struct net_device *in,
67	 const struct net_device *out,
68	 int (*okfn)(struct sk_buff *))
69{
70	return ip6t_do_table(skb, hook, in, out, &packet_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, &packet_filter);
91}
92
93static struct nf_hook_ops ip6t_ops[] = {
94	{
95		.hook		= ip6t_hook,
96		.owner		= THIS_MODULE,
97		.pf		= PF_INET6,
98		.hooknum	= NF_INET_LOCAL_IN,
99		.priority	= NF_IP6_PRI_FILTER,
100	},
101	{
102		.hook		= ip6t_hook,
103		.owner		= THIS_MODULE,
104		.pf		= PF_INET6,
105		.hooknum	= NF_INET_FORWARD,
106		.priority	= NF_IP6_PRI_FILTER,
107	},
108	{
109		.hook		= ip6t_local_out_hook,
110		.owner		= THIS_MODULE,
111		.pf		= PF_INET6,
112		.hooknum	= NF_INET_LOCAL_OUT,
113		.priority	= NF_IP6_PRI_FILTER,
114	},
115};
116
117/* Default to forward because I got too much mail already. */
118static int forward = NF_ACCEPT;
119module_param(forward, bool, 0000);
120
121static int __init ip6table_filter_init(void)
122{
123	int ret;
124
125	if (forward < 0 || forward > NF_MAX_VERDICT) {
126		printk("iptables forward must be 0 or 1\n");
127		return -EINVAL;
128	}
129
130	/* Entry 1 is the FORWARD hook */
131	initial_table.entries[1].target.verdict = -forward - 1;
132
133	/* Register table */
134	ret = ip6t_register_table(&packet_filter, &initial_table.repl);
135	if (ret < 0)
136		return ret;
137
138	/* Register hooks */
139	ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
140	if (ret < 0)
141		goto cleanup_table;
142
143	return ret;
144
145 cleanup_table:
146	ip6t_unregister_table(&packet_filter);
147	return ret;
148}
149
150static void __exit ip6table_filter_fini(void)
151{
152	nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
153	ip6t_unregister_table(&packet_filter);
154}
155
156module_init(ip6table_filter_init);
157module_exit(ip6table_filter_fini);
158