[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 <linux/slab.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 const struct xt_table packet_filter = {
	.name		= "filter",
	.valid_hooks	= FILTER_VALID_HOOKS,
	.me		= THIS_MODULE,
	.af		= NFPROTO_IPV4,
	.priority	= NF_IP_PRI_FILTER,
};

static unsigned int
iptable_filter_hook(const struct nf_hook_ops *ops, struct sk_buff *skb,
		    const struct nf_hook_state *state)
{
	const struct net *net;

	if (ops->hooknum == 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(state->in ? state->in : state->out);
	return ipt_do_table(skb, ops->hooknum, state, net->ipv4.iptable_filter);
}

static struct nf_hook_ops *filter_ops __read_mostly;

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

static int __net_init iptable_filter_net_init(struct net *net)
{
	struct ipt_replace *repl;

	repl = ipt_alloc_initial_table(&packet_filter);
	if (repl == NULL)
		return -ENOMEM;
	/* Entry 1 is the FORWARD hook */
	((struct ipt_standard *)repl->entries)[1].target.verdict =
		forward ? -NF_ACCEPT - 1 : -NF_DROP - 1;

	net->ipv4.iptable_filter =
		ipt_register_table(net, &packet_filter, repl);
	kfree(repl);
	return PTR_ERR_OR_ZERO(net->ipv4.iptable_filter);
}

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;

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

	/* Register hooks */
	filter_ops = xt_hook_link(&packet_filter, iptable_filter_hook);
	if (IS_ERR(filter_ops)) {
		ret = PTR_ERR(filter_ops);
		unregister_pernet_subsys(&iptable_filter_net_ops);
	}

	return ret;
}

static void __exit iptable_filter_fini(void)
{
	xt_hook_unlink(&packet_filter, filter_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>
5a0e3ad6	16	#include <linux/slab.h>
c9bdd4b5	17	#include <net/ip.h>
1da177e4 LT	18
	19	MODULE_LICENSE("GPL");
	20	MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
	21	MODULE_DESCRIPTION("iptables filter table");
	22
6e23ae2a PM	23	#define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) \| \
	24	(1 << NF_INET_FORWARD) \| \
	25	(1 << NF_INET_LOCAL_OUT))
1da177e4	26
35aad0ff	27	static const struct xt_table packet_filter = {
1da177e4 LT	28	.name = "filter",
1da177e4 LT	29	.valid_hooks = FILTER_VALID_HOOKS,
2e4e6a17	30	.me = THIS_MODULE,
f88e6a8a	31	.af = NFPROTO_IPV4,
2b95efe7	32	.priority = NF_IP_PRI_FILTER,
1da177e4 LT	33	};
1da177e4 LT	34
666953df	35	static unsigned int
795aa6ef	36	iptable_filter_hook(const struct nf_hook_ops ops, struct sk_buff skb,
238e54c9	37	const struct nf_hook_state *state)
666953df	38	{
2b21e051	39	const struct net *net;
666953df	40
795aa6ef	41	if (ops->hooknum == NF_INET_LOCAL_OUT &&
2b21e051 JE	42	(skb->len < sizeof(struct iphdr) \|\|
	43	ip_hdrlen(skb) < sizeof(struct iphdr)))
	44	/* root is playing with raw sockets. */
	45	return NF_ACCEPT;
1da177e4	46
238e54c9	47	net = dev_net(state->in ? state->in : state->out);
1c491ba2	48	return ipt_do_table(skb, ops->hooknum, state, net->ipv4.iptable_filter);
1da177e4 LT	49	}
1da177e4 LT	50
2b95efe7	51	static struct nf_hook_ops *filter_ops __read_mostly;
1da177e4 LT	52
1da177e4 LT	53	/* Default to forward because I got too much mail already. */
523f610e	54	static bool forward = true;
1da177e4 LT	55	module_param(forward, bool, 0000);
1da177e4 LT	56
9335f047 AD	57	static int __net_init iptable_filter_net_init(struct net *net)
9335f047 AD	58	{
e3eaa991 JE	59	struct ipt_replace *repl;
	60
	61	repl = ipt_alloc_initial_table(&packet_filter);
	62	if (repl == NULL)
	63	return -ENOMEM;
	64	/* Entry 1 is the FORWARD hook */
	65	((struct ipt_standard *)repl->entries)[1].target.verdict =
523f610e	66	forward ? -NF_ACCEPT - 1 : -NF_DROP - 1;
e3eaa991	67
9335f047	68	net->ipv4.iptable_filter =
e3eaa991 JE	69	ipt_register_table(net, &packet_filter, repl);
e3eaa991 JE	70	kfree(repl);
8c6ffba0	71	return PTR_ERR_OR_ZERO(net->ipv4.iptable_filter);
9335f047 AD	72	}
	73
	74	static void __net_exit iptable_filter_net_exit(struct net *net)
	75	{
f54e9367	76	ipt_unregister_table(net, net->ipv4.iptable_filter);
9335f047 AD	77	}
	78
	79	static struct pernet_operations iptable_filter_net_ops = {
	80	.init = iptable_filter_net_init,
	81	.exit = iptable_filter_net_exit,
	82	};
	83
65b4b4e8	84	static int __init iptable_filter_init(void)
1da177e4 LT	85	{
	86	int ret;
	87
9335f047 AD	88	ret = register_pernet_subsys(&iptable_filter_net_ops);
	89	if (ret < 0)
	90	return ret;
1da177e4 LT	91
1da177e4 LT	92	/* Register hooks */
2b95efe7 JE	93	filter_ops = xt_hook_link(&packet_filter, iptable_filter_hook);
	94	if (IS_ERR(filter_ops)) {
	95	ret = PTR_ERR(filter_ops);
90efbed1	96	unregister_pernet_subsys(&iptable_filter_net_ops);
2b95efe7	97	}
1da177e4	98
1da177e4	99	return ret;
1da177e4 LT	100	}
1da177e4 LT	101
65b4b4e8	102	static void __exit iptable_filter_fini(void)
1da177e4	103	{
2b95efe7	104	xt_hook_unlink(&packet_filter, filter_ops);
9335f047	105	unregister_pernet_subsys(&iptable_filter_net_ops);
1da177e4 LT	106	}
1da177e4 LT	107
65b4b4e8 AM	108	module_init(iptable_filter_init);
65b4b4e8 AM	109	module_exit(iptable_filter_fini);