[deliverable/linux.git] / net / ipv4 / netfilter / iptable_filter.c

/*
 * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x.
 *
 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
 * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <net/ip.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
MODULE_DESCRIPTION("iptables filter table");

#define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) | \
			    (1 << NF_INET_FORWARD) | \
			    (1 << NF_INET_LOCAL_OUT))

static struct
{
	struct ipt_replace repl;
	struct ipt_standard entries[3];
	struct ipt_error term;
} initial_table __net_initdata = {
	.repl = {
		.name = "filter",
		.valid_hooks = FILTER_VALID_HOOKS,
		.num_entries = 4,
		.size = sizeof(struct ipt_standard) * 3 + sizeof(struct ipt_error),
		.hook_entry = {
			[NF_INET_LOCAL_IN] = 0,
			[NF_INET_FORWARD] = sizeof(struct ipt_standard),
			[NF_INET_LOCAL_OUT] = sizeof(struct ipt_standard) * 2,
		},
		.underflow = {
			[NF_INET_LOCAL_IN] = 0,
			[NF_INET_FORWARD] = sizeof(struct ipt_standard),
			[NF_INET_LOCAL_OUT] = sizeof(struct ipt_standard) * 2,
		},
	},
	.entries = {
		IPT_STANDARD_INIT(NF_ACCEPT),	/* LOCAL_IN */
		IPT_STANDARD_INIT(NF_ACCEPT),	/* FORWARD */
		IPT_STANDARD_INIT(NF_ACCEPT),	/* LOCAL_OUT */
	},
	.term = IPT_ERROR_INIT,			/* ERROR */
};

static const struct xt_table packet_filter = {
	.name		= "filter",
	.valid_hooks	= FILTER_VALID_HOOKS,
	.me		= THIS_MODULE,
	.af		= NFPROTO_IPV4,
};

static unsigned int
iptable_filter_hook(unsigned int hook, struct sk_buff *skb,
		    const struct net_device *in, const struct net_device *out,
		    int (*okfn)(struct sk_buff *))
{
	const struct net *net;

	if (hook == NF_INET_LOCAL_OUT &&
	    (skb->len < sizeof(struct iphdr) ||
	     ip_hdrlen(skb) < sizeof(struct iphdr)))
		/* root is playing with raw sockets. */
		return NF_ACCEPT;

	net = dev_net((in != NULL) ? in : out);
	return ipt_do_table(skb, hook, in, out, net->ipv4.iptable_filter);
}

static struct nf_hook_ops ipt_ops[] __read_mostly = {
	{
		.hook		= iptable_filter_hook,
		.owner		= THIS_MODULE,
		.pf		= NFPROTO_IPV4,
		.hooknum	= NF_INET_LOCAL_IN,
		.priority	= NF_IP_PRI_FILTER,
	},
	{
		.hook		= iptable_filter_hook,
		.owner		= THIS_MODULE,
		.pf		= NFPROTO_IPV4,
		.hooknum	= NF_INET_FORWARD,
		.priority	= NF_IP_PRI_FILTER,
	},
	{
		.hook		= iptable_filter_hook,
		.owner		= THIS_MODULE,
		.pf		= NFPROTO_IPV4,
		.hooknum	= NF_INET_LOCAL_OUT,
		.priority	= NF_IP_PRI_FILTER,
	},
};

/* Default to forward because I got too much mail already. */
static int forward = NF_ACCEPT;
module_param(forward, bool, 0000);

static int __net_init iptable_filter_net_init(struct net *net)
{
	/* Register table */
	net->ipv4.iptable_filter =
		ipt_register_table(net, &packet_filter, &initial_table.repl);
	if (IS_ERR(net->ipv4.iptable_filter))
		return PTR_ERR(net->ipv4.iptable_filter);
	return 0;
}

static void __net_exit iptable_filter_net_exit(struct net *net)
{
	ipt_unregister_table(net, net->ipv4.iptable_filter);
}

static struct pernet_operations iptable_filter_net_ops = {
	.init = iptable_filter_net_init,
	.exit = iptable_filter_net_exit,
};

static int __init iptable_filter_init(void)
{
	int ret;

	if (forward < 0 || forward > NF_MAX_VERDICT) {
		printk("iptables forward must be 0 or 1\n");
		return -EINVAL;
	}

	/* Entry 1 is the FORWARD hook */
	initial_table.entries[1].target.verdict = -forward - 1;

	ret = register_pernet_subsys(&iptable_filter_net_ops);
	if (ret < 0)
		return ret;

	/* Register hooks */
	ret = nf_register_hooks(ipt_ops, ARRAY_SIZE(ipt_ops));
	if (ret < 0)
		goto cleanup_table;

	return ret;

 cleanup_table:
	unregister_pernet_subsys(&iptable_filter_net_ops);
	return ret;
}

static void __exit iptable_filter_fini(void)
{
	nf_unregister_hooks(ipt_ops, ARRAY_SIZE(ipt_ops));
	unregister_pernet_subsys(&iptable_filter_net_ops);
}

module_init(iptable_filter_init);
module_exit(iptable_filter_fini);
Commit	Line	Data
1da177e4 LT	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
	13	#include <linux/module.h>
	14	#include <linux/moduleparam.h>
	15	#include <linux/netfilter_ipv4/ip_tables.h>
c9bdd4b5	16	#include <net/ip.h>
1da177e4 LT	17
	18	MODULE_LICENSE("GPL");
	19	MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
	20	MODULE_DESCRIPTION("iptables filter table");
	21
6e23ae2a PM	22	#define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) \| \
	23	(1 << NF_INET_FORWARD) \| \
	24	(1 << NF_INET_LOCAL_OUT))
1da177e4 LT	25
	26	static struct
	27	{
	28	struct ipt_replace repl;
	29	struct ipt_standard entries[3];
	30	struct ipt_error term;
9335f047	31	} initial_table __net_initdata = {
3c2ad469 PM	32	.repl = {
	33	.name = "filter",
	34	.valid_hooks = FILTER_VALID_HOOKS,
	35	.num_entries = 4,
	36	.size = sizeof(struct ipt_standard) * 3 + sizeof(struct ipt_error),
	37	.hook_entry = {
6e23ae2a PM	38	[NF_INET_LOCAL_IN] = 0,
	39	[NF_INET_FORWARD] = sizeof(struct ipt_standard),
	40	[NF_INET_LOCAL_OUT] = sizeof(struct ipt_standard) * 2,
3c2ad469 PM	41	},
3c2ad469 PM	42	.underflow = {
6e23ae2a PM	43	[NF_INET_LOCAL_IN] = 0,
	44	[NF_INET_FORWARD] = sizeof(struct ipt_standard),
	45	[NF_INET_LOCAL_OUT] = sizeof(struct ipt_standard) * 2,
3c2ad469 PM	46	},
	47	},
	48	.entries = {
	49	IPT_STANDARD_INIT(NF_ACCEPT), /* LOCAL_IN */
	50	IPT_STANDARD_INIT(NF_ACCEPT), /* FORWARD */
	51	IPT_STANDARD_INIT(NF_ACCEPT), /* LOCAL_OUT */
	52	},
	53	.term = IPT_ERROR_INIT, /* ERROR */
1da177e4 LT	54	};
1da177e4 LT	55
35aad0ff	56	static const struct xt_table packet_filter = {
1da177e4 LT	57	.name = "filter",
1da177e4 LT	58	.valid_hooks = FILTER_VALID_HOOKS,
2e4e6a17	59	.me = THIS_MODULE,
f88e6a8a	60	.af = NFPROTO_IPV4,
1da177e4 LT	61	};
1da177e4 LT	62
666953df	63	static unsigned int
737535c5 JE	64	iptable_filter_hook(unsigned int hook, struct sk_buff *skb,
	65	const struct net_device in, const struct net_device out,
	66	int (okfn)(struct sk_buff ))
666953df	67	{
2b21e051	68	const struct net *net;
666953df	69
2b21e051 JE	70	if (hook == NF_INET_LOCAL_OUT &&
	71	(skb->len < sizeof(struct iphdr) \|\|
	72	ip_hdrlen(skb) < sizeof(struct iphdr)))
	73	/* root is playing with raw sockets. */
	74	return NF_ACCEPT;
1da177e4	75
2b21e051 JE	76	net = dev_net((in != NULL) ? in : out);
2b21e051 JE	77	return ipt_do_table(skb, hook, in, out, net->ipv4.iptable_filter);
1da177e4 LT	78	}
1da177e4 LT	79
1999414a	80	static struct nf_hook_ops ipt_ops[] __read_mostly = {
1da177e4	81	{
737535c5	82	.hook = iptable_filter_hook,
1da177e4	83	.owner = THIS_MODULE,
24c232d8	84	.pf = NFPROTO_IPV4,
6e23ae2a	85	.hooknum = NF_INET_LOCAL_IN,
1da177e4 LT	86	.priority = NF_IP_PRI_FILTER,
	87	},
	88	{
737535c5	89	.hook = iptable_filter_hook,
1da177e4	90	.owner = THIS_MODULE,
24c232d8	91	.pf = NFPROTO_IPV4,
6e23ae2a	92	.hooknum = NF_INET_FORWARD,
1da177e4 LT	93	.priority = NF_IP_PRI_FILTER,
	94	},
	95	{
737535c5	96	.hook = iptable_filter_hook,
1da177e4	97	.owner = THIS_MODULE,
24c232d8	98	.pf = NFPROTO_IPV4,
6e23ae2a	99	.hooknum = NF_INET_LOCAL_OUT,
1da177e4 LT	100	.priority = NF_IP_PRI_FILTER,
	101	},
	102	};
	103
	104	/* Default to forward because I got too much mail already. */
	105	static int forward = NF_ACCEPT;
	106	module_param(forward, bool, 0000);
	107
9335f047 AD	108	static int __net_init iptable_filter_net_init(struct net *net)
	109	{
	110	/* Register table */
	111	net->ipv4.iptable_filter =
	112	ipt_register_table(net, &packet_filter, &initial_table.repl);
	113	if (IS_ERR(net->ipv4.iptable_filter))
	114	return PTR_ERR(net->ipv4.iptable_filter);
	115	return 0;
	116	}
	117
	118	static void __net_exit iptable_filter_net_exit(struct net *net)
	119	{
f54e9367	120	ipt_unregister_table(net, net->ipv4.iptable_filter);
9335f047 AD	121	}
	122
	123	static struct pernet_operations iptable_filter_net_ops = {
	124	.init = iptable_filter_net_init,
	125	.exit = iptable_filter_net_exit,
	126	};
	127
65b4b4e8	128	static int __init iptable_filter_init(void)
1da177e4 LT	129	{
	130	int ret;
	131
	132	if (forward < 0 \|\| forward > NF_MAX_VERDICT) {
	133	printk("iptables forward must be 0 or 1\n");
	134	return -EINVAL;
	135	}
	136
	137	/* Entry 1 is the FORWARD hook */
	138	initial_table.entries[1].target.verdict = -forward - 1;
	139
9335f047 AD	140	ret = register_pernet_subsys(&iptable_filter_net_ops);
	141	if (ret < 0)
	142	return ret;
1da177e4 LT	143
1da177e4 LT	144	/* Register hooks */
964ddaa1	145	ret = nf_register_hooks(ipt_ops, ARRAY_SIZE(ipt_ops));
1da177e4 LT	146	if (ret < 0)
	147	goto cleanup_table;
	148
1da177e4 LT	149	return ret;
1da177e4 LT	150
1da177e4	151	cleanup_table:
9335f047	152	unregister_pernet_subsys(&iptable_filter_net_ops);
1da177e4 LT	153	return ret;
	154	}
	155
65b4b4e8	156	static void __exit iptable_filter_fini(void)
1da177e4	157	{
964ddaa1	158	nf_unregister_hooks(ipt_ops, ARRAY_SIZE(ipt_ops));
9335f047	159	unregister_pernet_subsys(&iptable_filter_net_ops);
1da177e4 LT	160	}
1da177e4 LT	161
65b4b4e8 AM	162	module_init(iptable_filter_init);
65b4b4e8 AM	163	module_exit(iptable_filter_fini);