[net-next-2.6.git] / net / ipv4 / netfilter / ipt_REDIRECT.c

/* Redirect.  Simple mapping which alters dst to a local IP address. */
/* (C) 1999-2001 Paul `Rusty' Russell
 * (C) 2002-2006 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/types.h>
#include <linux/ip.h>
#include <linux/timer.h>
#include <linux/module.h>
#include <linux/netfilter.h>
#include <linux/netdevice.h>
#include <linux/if.h>
#include <linux/inetdevice.h>
#include <net/protocol.h>
#include <net/checksum.h>
#include <linux/netfilter_ipv4.h>
#ifdef CONFIG_NF_NAT_NEEDED
#include <net/netfilter/nf_nat_rule.h>
#else
#include <linux/netfilter_ipv4/ip_nat_rule.h>
#endif

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
MODULE_DESCRIPTION("iptables REDIRECT target module");

#if 0
#define DEBUGP printk
#else
#define DEBUGP(format, args...)
#endif

/* FIXME: Take multiple ranges --RR */
static int
redirect_check(const char *tablename,
	       const void *e,
	       const struct xt_target *target,
	       void *targinfo,
	       unsigned int hook_mask)
{
	const struct ip_nat_multi_range_compat *mr = targinfo;

	if (mr->range[0].flags & IP_NAT_RANGE_MAP_IPS) {
		DEBUGP("redirect_check: bad MAP_IPS.\n");
		return 0;
	}
	if (mr->rangesize != 1) {
		DEBUGP("redirect_check: bad rangesize %u.\n", mr->rangesize);
		return 0;
	}
	return 1;
}

static unsigned int
redirect_target(struct sk_buff **pskb,
		const struct net_device *in,
		const struct net_device *out,
		unsigned int hooknum,
		const struct xt_target *target,
		const void *targinfo)
{
	struct ip_conntrack *ct;
	enum ip_conntrack_info ctinfo;
	__be32 newdst;
	const struct ip_nat_multi_range_compat *mr = targinfo;
	struct ip_nat_range newrange;

	IP_NF_ASSERT(hooknum == NF_IP_PRE_ROUTING
		     || hooknum == NF_IP_LOCAL_OUT);

	ct = ip_conntrack_get(*pskb, &ctinfo);
	IP_NF_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED));

	/* Local packets: make them go to loopback */
	if (hooknum == NF_IP_LOCAL_OUT)
		newdst = htonl(0x7F000001);
	else {
		struct in_device *indev;
		struct in_ifaddr *ifa;

		newdst = 0;
		
		rcu_read_lock();
		indev = __in_dev_get_rcu((*pskb)->dev);
		if (indev && (ifa = indev->ifa_list))
			newdst = ifa->ifa_local;
		rcu_read_unlock();

		if (!newdst)
			return NF_DROP;
	}

	/* Transfer from original range. */
	newrange = ((struct ip_nat_range)
		{ mr->range[0].flags | IP_NAT_RANGE_MAP_IPS,
		  newdst, newdst,
		  mr->range[0].min, mr->range[0].max });

	/* Hand modified range to generic setup. */
	return ip_nat_setup_info(ct, &newrange, hooknum);
}

static struct ipt_target redirect_reg = {
	.name		= "REDIRECT",
	.target		= redirect_target,
	.targetsize	= sizeof(struct ip_nat_multi_range_compat),
	.table		= "nat",
	.hooks		= (1 << NF_IP_PRE_ROUTING) | (1 << NF_IP_LOCAL_OUT),
	.checkentry	= redirect_check,
	.me		= THIS_MODULE,
};

static int __init ipt_redirect_init(void)
{
	return ipt_register_target(&redirect_reg);
}

static void __exit ipt_redirect_fini(void)
{
	ipt_unregister_target(&redirect_reg);
}

module_init(ipt_redirect_init);
module_exit(ipt_redirect_fini);
Commit	Line	Data
1da177e4 LT	1	/* Redirect. Simple mapping which alters dst to a local IP address. */
1da177e4 LT	2	/* (C) 1999-2001 Paul `Rusty' Russell
5b1158e9	3	* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
1da177e4 LT	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License version 2 as
	7	* published by the Free Software Foundation.
	8	*/
	9
	10	#include <linux/types.h>
	11	#include <linux/ip.h>
	12	#include <linux/timer.h>
	13	#include <linux/module.h>
	14	#include <linux/netfilter.h>
	15	#include <linux/netdevice.h>
	16	#include <linux/if.h>
	17	#include <linux/inetdevice.h>
	18	#include <net/protocol.h>
	19	#include <net/checksum.h>
	20	#include <linux/netfilter_ipv4.h>
5b1158e9 JK	21	#ifdef CONFIG_NF_NAT_NEEDED
	22	#include <net/netfilter/nf_nat_rule.h>
	23	#else
1da177e4	24	#include <linux/netfilter_ipv4/ip_nat_rule.h>
5b1158e9	25	#endif
1da177e4 LT	26
	27	MODULE_LICENSE("GPL");
	28	MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
	29	MODULE_DESCRIPTION("iptables REDIRECT target module");
	30
	31	#if 0
	32	#define DEBUGP printk
	33	#else
	34	#define DEBUGP(format, args...)
	35	#endif
	36
	37	/* FIXME: Take multiple ranges --RR */
	38	static int
	39	redirect_check(const char *tablename,
2e4e6a17	40	const void *e,
c4986734	41	const struct xt_target *target,
1da177e4	42	void *targinfo,
1da177e4 LT	43	unsigned int hook_mask)
	44	{
	45	const struct ip_nat_multi_range_compat *mr = targinfo;
	46
1da177e4 LT	47	if (mr->range[0].flags & IP_NAT_RANGE_MAP_IPS) {
	48	DEBUGP("redirect_check: bad MAP_IPS.\n");
	49	return 0;
	50	}
	51	if (mr->rangesize != 1) {
	52	DEBUGP("redirect_check: bad rangesize %u.\n", mr->rangesize);
	53	return 0;
	54	}
	55	return 1;
	56	}
	57
	58	static unsigned int
	59	redirect_target(struct sk_buff **pskb,
	60	const struct net_device *in,
	61	const struct net_device *out,
	62	unsigned int hooknum,
c4986734	63	const struct xt_target *target,
fe1cb108	64	const void *targinfo)
1da177e4 LT	65	{
	66	struct ip_conntrack *ct;
	67	enum ip_conntrack_info ctinfo;
a144ea4b	68	__be32 newdst;
1da177e4 LT	69	const struct ip_nat_multi_range_compat *mr = targinfo;
	70	struct ip_nat_range newrange;
	71
	72	IP_NF_ASSERT(hooknum == NF_IP_PRE_ROUTING
	73	\|\| hooknum == NF_IP_LOCAL_OUT);
	74
	75	ct = ip_conntrack_get(*pskb, &ctinfo);
	76	IP_NF_ASSERT(ct && (ctinfo == IP_CT_NEW \|\| ctinfo == IP_CT_RELATED));
	77
	78	/* Local packets: make them go to loopback */
	79	if (hooknum == NF_IP_LOCAL_OUT)
	80	newdst = htonl(0x7F000001);
	81	else {
	82	struct in_device *indev;
cd0bf2d7	83	struct in_ifaddr *ifa;
1da177e4	84
cd0bf2d7 PM	85	newdst = 0;
	86
	87	rcu_read_lock();
e5ed6399	88	indev = __in_dev_get_rcu((*pskb)->dev);
cd0bf2d7 PM	89	if (indev && (ifa = indev->ifa_list))
	90	newdst = ifa->ifa_local;
	91	rcu_read_unlock();
1da177e4	92
cd0bf2d7 PM	93	if (!newdst)
cd0bf2d7 PM	94	return NF_DROP;
1da177e4 LT	95	}
	96
	97	/* Transfer from original range. */
	98	newrange = ((struct ip_nat_range)
	99	{ mr->range[0].flags \| IP_NAT_RANGE_MAP_IPS,
	100	newdst, newdst,
	101	mr->range[0].min, mr->range[0].max });
	102
	103	/* Hand modified range to generic setup. */
	104	return ip_nat_setup_info(ct, &newrange, hooknum);
	105	}
	106
	107	static struct ipt_target redirect_reg = {
	108	.name = "REDIRECT",
	109	.target = redirect_target,
1d5cd909 PM	110	.targetsize = sizeof(struct ip_nat_multi_range_compat),
	111	.table = "nat",
	112	.hooks = (1 << NF_IP_PRE_ROUTING) \| (1 << NF_IP_LOCAL_OUT),
1da177e4 LT	113	.checkentry = redirect_check,
	114	.me = THIS_MODULE,
	115	};
	116
65b4b4e8	117	static int __init ipt_redirect_init(void)
1da177e4 LT	118	{
	119	return ipt_register_target(&redirect_reg);
	120	}
	121
65b4b4e8	122	static void __exit ipt_redirect_fini(void)
1da177e4 LT	123	{
	124	ipt_unregister_target(&redirect_reg);
	125	}
	126
65b4b4e8 AM	127	module_init(ipt_redirect_init);
65b4b4e8 AM	128	module_exit(ipt_redirect_fini);