[deliverable/linux.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) 2002-2004 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/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>
#include <linux/netfilter_ipv4/ip_nat_rule.h>

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 targinfosize,
	       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,
		void *userinfo)
{
	struct ip_conntrack *ct;
	enum ip_conntrack_info ctinfo;
	u_int32_t 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 init(void)
{
	return ipt_register_target(&redirect_reg);
}

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

module_init(init);
module_exit(fini);
Commit	Line	Data
1da177e4 LT	1	/* Redirect. Simple mapping which alters dst to a local IP address. */
	2	/* (C) 1999-2001 Paul `Rusty' Russell
	3	* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
	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>
	21	#include <linux/netfilter_ipv4/ip_nat_rule.h>
	22
	23	MODULE_LICENSE("GPL");
	24	MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
	25	MODULE_DESCRIPTION("iptables REDIRECT target module");
	26
	27	#if 0
	28	#define DEBUGP printk
	29	#else
	30	#define DEBUGP(format, args...)
	31	#endif
	32
	33	/* FIXME: Take multiple ranges --RR */
	34	static int
	35	redirect_check(const char *tablename,
2e4e6a17	36	const void *e,
c4986734	37	const struct xt_target *target,
1da177e4 LT	38	void *targinfo,
	39	unsigned int targinfosize,
	40	unsigned int hook_mask)
	41	{
	42	const struct ip_nat_multi_range_compat *mr = targinfo;
	43
1da177e4 LT	44	if (mr->range[0].flags & IP_NAT_RANGE_MAP_IPS) {
	45	DEBUGP("redirect_check: bad MAP_IPS.\n");
	46	return 0;
	47	}
	48	if (mr->rangesize != 1) {
	49	DEBUGP("redirect_check: bad rangesize %u.\n", mr->rangesize);
	50	return 0;
	51	}
	52	return 1;
	53	}
	54
	55	static unsigned int
	56	redirect_target(struct sk_buff **pskb,
	57	const struct net_device *in,
	58	const struct net_device *out,
	59	unsigned int hooknum,
c4986734	60	const struct xt_target *target,
1da177e4 LT	61	const void *targinfo,
	62	void *userinfo)
	63	{
	64	struct ip_conntrack *ct;
	65	enum ip_conntrack_info ctinfo;
	66	u_int32_t newdst;
	67	const struct ip_nat_multi_range_compat *mr = targinfo;
	68	struct ip_nat_range newrange;
	69
	70	IP_NF_ASSERT(hooknum == NF_IP_PRE_ROUTING
	71	\|\| hooknum == NF_IP_LOCAL_OUT);
	72
	73	ct = ip_conntrack_get(*pskb, &ctinfo);
	74	IP_NF_ASSERT(ct && (ctinfo == IP_CT_NEW \|\| ctinfo == IP_CT_RELATED));
	75
	76	/* Local packets: make them go to loopback */
	77	if (hooknum == NF_IP_LOCAL_OUT)
	78	newdst = htonl(0x7F000001);
	79	else {
	80	struct in_device *indev;
cd0bf2d7	81	struct in_ifaddr *ifa;
1da177e4	82
cd0bf2d7 PM	83	newdst = 0;
	84
	85	rcu_read_lock();
e5ed6399	86	indev = __in_dev_get_rcu((*pskb)->dev);
cd0bf2d7 PM	87	if (indev && (ifa = indev->ifa_list))
	88	newdst = ifa->ifa_local;
	89	rcu_read_unlock();
1da177e4	90
cd0bf2d7 PM	91	if (!newdst)
cd0bf2d7 PM	92	return NF_DROP;
1da177e4 LT	93	}
	94
	95	/* Transfer from original range. */
	96	newrange = ((struct ip_nat_range)
	97	{ mr->range[0].flags \| IP_NAT_RANGE_MAP_IPS,
	98	newdst, newdst,
	99	mr->range[0].min, mr->range[0].max });
	100
	101	/* Hand modified range to generic setup. */
	102	return ip_nat_setup_info(ct, &newrange, hooknum);
	103	}
	104
	105	static struct ipt_target redirect_reg = {
	106	.name = "REDIRECT",
	107	.target = redirect_target,
1d5cd909 PM	108	.targetsize = sizeof(struct ip_nat_multi_range_compat),
	109	.table = "nat",
	110	.hooks = (1 << NF_IP_PRE_ROUTING) \| (1 << NF_IP_LOCAL_OUT),
1da177e4 LT	111	.checkentry = redirect_check,
	112	.me = THIS_MODULE,
	113	};
	114
	115	static int __init init(void)
	116	{
	117	return ipt_register_target(&redirect_reg);
	118	}
	119
	120	static void __exit fini(void)
	121	{
	122	ipt_unregister_target(&redirect_reg);
	123	}
	124
	125	module_init(init);
	126	module_exit(fini);