[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,
	       void *targinfo,
	       unsigned int targinfosize,
	       unsigned int hook_mask)
{
	const struct ip_nat_multi_range_compat *mr = targinfo;

	if (strcmp(tablename, "nat") != 0) {
		DEBUGP("redirect_check: bad table `%s'.\n", table);
		return 0;
	}
	if (targinfosize != IPT_ALIGN(sizeof(*mr))) {
		DEBUGP("redirect_check: size %u.\n", targinfosize);
		return 0;
	}
	if (hook_mask & ~((1 << NF_IP_PRE_ROUTING) | (1 << NF_IP_LOCAL_OUT))) {
		DEBUGP("redirect_check: bad hooks %x.\n", hook_mask);
		return 0;
	}
	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 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,
	.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,
1da177e4 LT	37	void *targinfo,
	38	unsigned int targinfosize,
	39	unsigned int hook_mask)
	40	{
	41	const struct ip_nat_multi_range_compat *mr = targinfo;
	42
	43	if (strcmp(tablename, "nat") != 0) {
	44	DEBUGP("redirect_check: bad table `%s'.\n", table);
	45	return 0;
	46	}
	47	if (targinfosize != IPT_ALIGN(sizeof(*mr))) {
	48	DEBUGP("redirect_check: size %u.\n", targinfosize);
	49	return 0;
	50	}
	51	if (hook_mask & ~((1 << NF_IP_PRE_ROUTING) \| (1 << NF_IP_LOCAL_OUT))) {
	52	DEBUGP("redirect_check: bad hooks %x.\n", hook_mask);
	53	return 0;
	54	}
	55	if (mr->range[0].flags & IP_NAT_RANGE_MAP_IPS) {
	56	DEBUGP("redirect_check: bad MAP_IPS.\n");
	57	return 0;
	58	}
	59	if (mr->rangesize != 1) {
	60	DEBUGP("redirect_check: bad rangesize %u.\n", mr->rangesize);
	61	return 0;
	62	}
	63	return 1;
	64	}
	65
	66	static unsigned int
	67	redirect_target(struct sk_buff **pskb,
	68	const struct net_device *in,
	69	const struct net_device *out,
	70	unsigned int hooknum,
	71	const void *targinfo,
	72	void *userinfo)
	73	{
	74	struct ip_conntrack *ct;
	75	enum ip_conntrack_info ctinfo;
	76	u_int32_t newdst;
	77	const struct ip_nat_multi_range_compat *mr = targinfo;
	78	struct ip_nat_range newrange;
	79
	80	IP_NF_ASSERT(hooknum == NF_IP_PRE_ROUTING
	81	\|\| hooknum == NF_IP_LOCAL_OUT);
	82
	83	ct = ip_conntrack_get(*pskb, &ctinfo);
	84	IP_NF_ASSERT(ct && (ctinfo == IP_CT_NEW \|\| ctinfo == IP_CT_RELATED));
	85
	86	/* Local packets: make them go to loopback */
	87	if (hooknum == NF_IP_LOCAL_OUT)
	88	newdst = htonl(0x7F000001);
	89	else {
	90	struct in_device *indev;
cd0bf2d7	91	struct in_ifaddr *ifa;
1da177e4	92
cd0bf2d7 PM	93	newdst = 0;
	94
	95	rcu_read_lock();
e5ed6399	96	indev = __in_dev_get_rcu((*pskb)->dev);
cd0bf2d7 PM	97	if (indev && (ifa = indev->ifa_list))
	98	newdst = ifa->ifa_local;
	99	rcu_read_unlock();
1da177e4	100
cd0bf2d7 PM	101	if (!newdst)
cd0bf2d7 PM	102	return NF_DROP;
1da177e4 LT	103	}
	104
	105	/* Transfer from original range. */
	106	newrange = ((struct ip_nat_range)
	107	{ mr->range[0].flags \| IP_NAT_RANGE_MAP_IPS,
	108	newdst, newdst,
	109	mr->range[0].min, mr->range[0].max });
	110
	111	/* Hand modified range to generic setup. */
	112	return ip_nat_setup_info(ct, &newrange, hooknum);
	113	}
	114
	115	static struct ipt_target redirect_reg = {
	116	.name = "REDIRECT",
	117	.target = redirect_target,
	118	.checkentry = redirect_check,
	119	.me = THIS_MODULE,
	120	};
	121
	122	static int __init init(void)
	123	{
	124	return ipt_register_target(&redirect_reg);
	125	}
	126
	127	static void __exit fini(void)
	128	{
	129	ipt_unregister_target(&redirect_reg);
	130	}
	131
	132	module_init(init);
	133	module_exit(fini);