[net-next-2.6.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 *))
{
	if (hook == NF_INET_LOCAL_OUT) {
		if (skb->len < sizeof(struct iphdr) ||
		    ip_hdrlen(skb) < sizeof(struct iphdr))
			/* root is playing with raw sockets. */
			return NF_ACCEPT;

		return ipt_do_table(skb, hook, in, out,
				    dev_net(out)->ipv4.iptable_filter);
	}

	/* LOCAL_IN/FORWARD: */
	return ipt_do_table(skb, hook, in, out,
			    dev_net(in)->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	{
737535c5 JE	68	if (hook == NF_INET_LOCAL_OUT) {
	69	if (skb->len < sizeof(struct iphdr) \|\|
	70	ip_hdrlen(skb) < sizeof(struct iphdr))
	71	/* root is playing with raw sockets. */
	72	return NF_ACCEPT;
666953df	73
737535c5 JE	74	return ipt_do_table(skb, hook, in, out,
	75	dev_net(out)->ipv4.iptable_filter);
	76	}
1da177e4	77
737535c5	78	/* LOCAL_IN/FORWARD: */
666953df	79	return ipt_do_table(skb, hook, in, out,
737535c5	80	dev_net(in)->ipv4.iptable_filter);
1da177e4 LT	81	}
1da177e4 LT	82
1999414a	83	static struct nf_hook_ops ipt_ops[] __read_mostly = {
1da177e4	84	{
737535c5	85	.hook = iptable_filter_hook,
1da177e4	86	.owner = THIS_MODULE,
24c232d8	87	.pf = NFPROTO_IPV4,
6e23ae2a	88	.hooknum = NF_INET_LOCAL_IN,
1da177e4 LT	89	.priority = NF_IP_PRI_FILTER,
	90	},
	91	{
737535c5	92	.hook = iptable_filter_hook,
1da177e4	93	.owner = THIS_MODULE,
24c232d8	94	.pf = NFPROTO_IPV4,
6e23ae2a	95	.hooknum = NF_INET_FORWARD,
1da177e4 LT	96	.priority = NF_IP_PRI_FILTER,
	97	},
	98	{
737535c5	99	.hook = iptable_filter_hook,
1da177e4	100	.owner = THIS_MODULE,
24c232d8	101	.pf = NFPROTO_IPV4,
6e23ae2a	102	.hooknum = NF_INET_LOCAL_OUT,
1da177e4 LT	103	.priority = NF_IP_PRI_FILTER,
	104	},
	105	};
	106
	107	/* Default to forward because I got too much mail already. */
	108	static int forward = NF_ACCEPT;
	109	module_param(forward, bool, 0000);
	110
9335f047 AD	111	static int __net_init iptable_filter_net_init(struct net *net)
	112	{
	113	/* Register table */
	114	net->ipv4.iptable_filter =
	115	ipt_register_table(net, &packet_filter, &initial_table.repl);
	116	if (IS_ERR(net->ipv4.iptable_filter))
	117	return PTR_ERR(net->ipv4.iptable_filter);
	118	return 0;
	119	}
	120
	121	static void __net_exit iptable_filter_net_exit(struct net *net)
	122	{
f54e9367	123	ipt_unregister_table(net, net->ipv4.iptable_filter);
9335f047 AD	124	}
	125
	126	static struct pernet_operations iptable_filter_net_ops = {
	127	.init = iptable_filter_net_init,
	128	.exit = iptable_filter_net_exit,
	129	};
	130
65b4b4e8	131	static int __init iptable_filter_init(void)
1da177e4 LT	132	{
	133	int ret;
	134
	135	if (forward < 0 \|\| forward > NF_MAX_VERDICT) {
	136	printk("iptables forward must be 0 or 1\n");
	137	return -EINVAL;
	138	}
	139
	140	/* Entry 1 is the FORWARD hook */
	141	initial_table.entries[1].target.verdict = -forward - 1;
	142
9335f047 AD	143	ret = register_pernet_subsys(&iptable_filter_net_ops);
	144	if (ret < 0)
	145	return ret;
1da177e4 LT	146
1da177e4 LT	147	/* Register hooks */
964ddaa1	148	ret = nf_register_hooks(ipt_ops, ARRAY_SIZE(ipt_ops));
1da177e4 LT	149	if (ret < 0)
	150	goto cleanup_table;
	151
1da177e4 LT	152	return ret;
1da177e4 LT	153
1da177e4	154	cleanup_table:
9335f047	155	unregister_pernet_subsys(&iptable_filter_net_ops);
1da177e4 LT	156	return ret;
	157	}
	158
65b4b4e8	159	static void __exit iptable_filter_fini(void)
1da177e4	160	{
964ddaa1	161	nf_unregister_hooks(ipt_ops, ARRAY_SIZE(ipt_ops));
9335f047	162	unregister_pernet_subsys(&iptable_filter_net_ops);
1da177e4 LT	163	}
1da177e4 LT	164
65b4b4e8 AM	165	module_init(iptable_filter_init);
65b4b4e8 AM	166	module_exit(iptable_filter_fini);