[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,
	.priority	= NF_IP_PRI_FILTER,
};

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 *filter_ops __read_mostly;

/* 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 */
	filter_ops = xt_hook_link(&packet_filter, iptable_filter_hook);
	if (IS_ERR(filter_ops)) {
		ret = PTR_ERR(filter_ops);
		goto cleanup_table;
	}

	return ret;

 cleanup_table:
	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
	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>
	16	#include <net/ip.h>
	17
	18	MODULE_LICENSE("GPL");
	19	MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
	20	MODULE_DESCRIPTION("iptables filter table");
	21
	22	#define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) \| \
	23	(1 << NF_INET_FORWARD) \| \
	24	(1 << NF_INET_LOCAL_OUT))
	25
	26	static struct
	27	{
	28	struct ipt_replace repl;
	29	struct ipt_standard entries[3];
	30	struct ipt_error term;
	31	} initial_table __net_initdata = {
	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 = {
	38	[NF_INET_LOCAL_IN] = 0,
	39	[NF_INET_FORWARD] = sizeof(struct ipt_standard),
	40	[NF_INET_LOCAL_OUT] = sizeof(struct ipt_standard) * 2,
	41	},
	42	.underflow = {
	43	[NF_INET_LOCAL_IN] = 0,
	44	[NF_INET_FORWARD] = sizeof(struct ipt_standard),
	45	[NF_INET_LOCAL_OUT] = sizeof(struct ipt_standard) * 2,
	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 */
	54	};
	55
	56	static const struct xt_table packet_filter = {
	57	.name = "filter",
	58	.valid_hooks = FILTER_VALID_HOOKS,
	59	.me = THIS_MODULE,
	60	.af = NFPROTO_IPV4,
	61	.priority = NF_IP_PRI_FILTER,
	62	};
	63
	64	static unsigned int
	65	iptable_filter_hook(unsigned int hook, struct sk_buff *skb,
	66	const struct net_device in, const struct net_device out,
	67	int (okfn)(struct sk_buff ))
	68	{
	69	const struct net *net;
	70
	71	if (hook == NF_INET_LOCAL_OUT &&
	72	(skb->len < sizeof(struct iphdr) \|\|
	73	ip_hdrlen(skb) < sizeof(struct iphdr)))
	74	/* root is playing with raw sockets. */
	75	return NF_ACCEPT;
	76
	77	net = dev_net((in != NULL) ? in : out);
	78	return ipt_do_table(skb, hook, in, out, net->ipv4.iptable_filter);
	79	}
	80
	81	static struct nf_hook_ops *filter_ops __read_mostly;
	82
	83	/* Default to forward because I got too much mail already. */
	84	static int forward = NF_ACCEPT;
	85	module_param(forward, bool, 0000);
	86
	87	static int __net_init iptable_filter_net_init(struct net *net)
	88	{
	89	/* Register table */
	90	net->ipv4.iptable_filter =
	91	ipt_register_table(net, &packet_filter, &initial_table.repl);
	92	if (IS_ERR(net->ipv4.iptable_filter))
	93	return PTR_ERR(net->ipv4.iptable_filter);
	94	return 0;
	95	}
	96
	97	static void __net_exit iptable_filter_net_exit(struct net *net)
	98	{
	99	ipt_unregister_table(net, net->ipv4.iptable_filter);
	100	}
	101
	102	static struct pernet_operations iptable_filter_net_ops = {
	103	.init = iptable_filter_net_init,
	104	.exit = iptable_filter_net_exit,
	105	};
	106
	107	static int __init iptable_filter_init(void)
	108	{
	109	int ret;
	110
	111	if (forward < 0 \|\| forward > NF_MAX_VERDICT) {
	112	printk("iptables forward must be 0 or 1\n");
	113	return -EINVAL;
	114	}
	115
	116	/* Entry 1 is the FORWARD hook */
	117	initial_table.entries[1].target.verdict = -forward - 1;
	118
	119	ret = register_pernet_subsys(&iptable_filter_net_ops);
	120	if (ret < 0)
	121	return ret;
	122
	123	/* Register hooks */
	124	filter_ops = xt_hook_link(&packet_filter, iptable_filter_hook);
	125	if (IS_ERR(filter_ops)) {
	126	ret = PTR_ERR(filter_ops);
	127	goto cleanup_table;
	128	}
	129
	130	return ret;
	131
	132	cleanup_table:
	133	unregister_pernet_subsys(&iptable_filter_net_ops);
	134	return ret;
	135	}
	136
	137	static void __exit iptable_filter_fini(void)
	138	{
	139	xt_hook_unlink(&packet_filter, filter_ops);
	140	unregister_pernet_subsys(&iptable_filter_net_ops);
	141	}
	142
	143	module_init(iptable_filter_init);
	144	module_exit(iptable_filter_fini);