[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) 2002-2006 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>
#include <linux/netfilter/x_tables.h>
#include <net/netfilter/nf_nat_rule.h>

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

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

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

static unsigned int
redirect_tg(struct sk_buff *skb, const struct net_device *in,
            const struct net_device *out, unsigned int hooknum,
            const struct xt_target *target, const void *targinfo)
{
	struct nf_conn *ct;
	enum ip_conntrack_info ctinfo;
	__be32 newdst;
	const struct nf_nat_multi_range_compat *mr = targinfo;
	struct nf_nat_range newrange;

	NF_CT_ASSERT(hooknum == NF_INET_PRE_ROUTING
		     || hooknum == NF_INET_LOCAL_OUT);

	ct = nf_ct_get(skb, &ctinfo);
	NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED));

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

		newdst = 0;

		rcu_read_lock();
		indev = __in_dev_get_rcu(skb->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 nf_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 nf_nat_setup_info(ct, &newrange, hooknum);
}

static struct xt_target redirect_tg_reg __read_mostly = {
	.name		= "REDIRECT",
	.family		= AF_INET,
	.target		= redirect_tg,
	.targetsize	= sizeof(struct nf_nat_multi_range_compat),
	.table		= "nat",
	.hooks		= (1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_OUT),
	.checkentry	= redirect_tg_check,
	.me		= THIS_MODULE,
};

static int __init redirect_tg_init(void)
{
	return xt_register_target(&redirect_tg_reg);
}

static void __exit redirect_tg_exit(void)
{
	xt_unregister_target(&redirect_tg_reg);
}

module_init(redirect_tg_init);
module_exit(redirect_tg_exit);
Commit	Line	Data
	1	/* Redirect. Simple mapping which alters dst to a local IP address. */
	2	/* (C) 1999-2001 Paul `Rusty' Russell
	3	* (C) 2002-2006 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/x_tables.h>
	22	#include <net/netfilter/nf_nat_rule.h>
	23
	24	MODULE_LICENSE("GPL");
	25	MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
	26	MODULE_DESCRIPTION("iptables REDIRECT target module");
	27
	28	/* FIXME: Take multiple ranges --RR */
	29	static bool
	30	redirect_tg_check(const char tablename, const void e,
	31	const struct xt_target target, void targinfo,
	32	unsigned int hook_mask)
	33	{
	34	const struct nf_nat_multi_range_compat *mr = targinfo;
	35
	36	if (mr->range[0].flags & IP_NAT_RANGE_MAP_IPS) {
	37	pr_debug("redirect_check: bad MAP_IPS.\n");
	38	return false;
	39	}
	40	if (mr->rangesize != 1) {
	41	pr_debug("redirect_check: bad rangesize %u.\n", mr->rangesize);
	42	return false;
	43	}
	44	return true;
	45	}
	46
	47	static unsigned int
	48	redirect_tg(struct sk_buff skb, const struct net_device in,
	49	const struct net_device *out, unsigned int hooknum,
	50	const struct xt_target target, const void targinfo)
	51	{
	52	struct nf_conn *ct;
	53	enum ip_conntrack_info ctinfo;
	54	__be32 newdst;
	55	const struct nf_nat_multi_range_compat *mr = targinfo;
	56	struct nf_nat_range newrange;
	57
	58	NF_CT_ASSERT(hooknum == NF_INET_PRE_ROUTING
	59	\|\| hooknum == NF_INET_LOCAL_OUT);
	60
	61	ct = nf_ct_get(skb, &ctinfo);
	62	NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW \|\| ctinfo == IP_CT_RELATED));
	63
	64	/* Local packets: make them go to loopback */
	65	if (hooknum == NF_INET_LOCAL_OUT)
	66	newdst = htonl(0x7F000001);
	67	else {
	68	struct in_device *indev;
	69	struct in_ifaddr *ifa;
	70
	71	newdst = 0;
	72
	73	rcu_read_lock();
	74	indev = __in_dev_get_rcu(skb->dev);
	75	if (indev && (ifa = indev->ifa_list))
	76	newdst = ifa->ifa_local;
	77	rcu_read_unlock();
	78
	79	if (!newdst)
	80	return NF_DROP;
	81	}
	82
	83	/* Transfer from original range. */
	84	newrange = ((struct nf_nat_range)
	85	{ mr->range[0].flags \| IP_NAT_RANGE_MAP_IPS,
	86	newdst, newdst,
	87	mr->range[0].min, mr->range[0].max });
	88
	89	/* Hand modified range to generic setup. */
	90	return nf_nat_setup_info(ct, &newrange, hooknum);
	91	}
	92
	93	static struct xt_target redirect_tg_reg __read_mostly = {
	94	.name = "REDIRECT",
	95	.family = AF_INET,
	96	.target = redirect_tg,
	97	.targetsize = sizeof(struct nf_nat_multi_range_compat),
	98	.table = "nat",
	99	.hooks = (1 << NF_INET_PRE_ROUTING) \| (1 << NF_INET_LOCAL_OUT),
	100	.checkentry = redirect_tg_check,
	101	.me = THIS_MODULE,
	102	};
	103
	104	static int __init redirect_tg_init(void)
	105	{
	106	return xt_register_target(&redirect_tg_reg);
	107	}
	108
	109	static void __exit redirect_tg_exit(void)
	110	{
	111	xt_unregister_target(&redirect_tg_reg);
	112	}
	113
	114	module_init(redirect_tg_init);
	115	module_exit(redirect_tg_exit);