[deliverable/linux.git] / net / ipv4 / netfilter / ipt_NETMAP.c

/* NETMAP - static NAT mapping of IP network addresses (1:1).
 * The mapping can be applied to source (POSTROUTING),
 * destination (PREROUTING), or both (with separate rules).
 */

/* (C) 2000-2001 Svenning Soerensen <svenning@post5.tele.dk>
 *
 * 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/config.h>
#include <linux/ip.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv4/ip_nat_rule.h>

#define MODULENAME "NETMAP"
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Svenning Soerensen <svenning@post5.tele.dk>");
MODULE_DESCRIPTION("iptables 1:1 NAT mapping of IP networks target");

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

static int
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(MODULENAME":check: bad MAP_IPS.\n");
		return 0;
	}
	if (mr->rangesize != 1) {
		DEBUGP(MODULENAME":check: bad rangesize %u.\n", mr->rangesize);
		return 0;
	}
	return 1;
}

static unsigned int
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 new_ip, netmask;
	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_POST_ROUTING
		     || hooknum == NF_IP_LOCAL_OUT);
	ct = ip_conntrack_get(*pskb, &ctinfo);

	netmask = ~(mr->range[0].min_ip ^ mr->range[0].max_ip);

	if (hooknum == NF_IP_PRE_ROUTING || hooknum == NF_IP_LOCAL_OUT)
		new_ip = (*pskb)->nh.iph->daddr & ~netmask;
	else
		new_ip = (*pskb)->nh.iph->saddr & ~netmask;
	new_ip |= mr->range[0].min_ip & netmask;

	newrange = ((struct ip_nat_range)
		{ mr->range[0].flags | IP_NAT_RANGE_MAP_IPS,
		  new_ip, new_ip,
		  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 target_module = { 
	.name 		= MODULENAME,
	.target 	= target, 
	.targetsize	= sizeof(struct ip_nat_multi_range_compat),
	.table		= "nat",
	.hooks		= (1 << NF_IP_PRE_ROUTING) | (1 << NF_IP_POST_ROUTING) |
			  (1 << NF_IP_LOCAL_OUT),
	.checkentry 	= check,
    	.me 		= THIS_MODULE 
};

static int __init init(void)
{
	return ipt_register_target(&target_module);
}

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

module_init(init);
module_exit(fini);
Commit	Line	Data
1da177e4 LT	1	/* NETMAP - static NAT mapping of IP network addresses (1:1).
	2	* The mapping can be applied to source (POSTROUTING),
	3	* destination (PREROUTING), or both (with separate rules).
	4	*/
	5
	6	/* (C) 2000-2001 Svenning Soerensen <svenning@post5.tele.dk>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*/
	12
	13	#include <linux/config.h>
	14	#include <linux/ip.h>
	15	#include <linux/module.h>
	16	#include <linux/netdevice.h>
	17	#include <linux/netfilter.h>
	18	#include <linux/netfilter_ipv4.h>
	19	#include <linux/netfilter_ipv4/ip_nat_rule.h>
	20
	21	#define MODULENAME "NETMAP"
	22	MODULE_LICENSE("GPL");
	23	MODULE_AUTHOR("Svenning Soerensen <svenning@post5.tele.dk>");
	24	MODULE_DESCRIPTION("iptables 1:1 NAT mapping of IP networks target");
	25
	26	#if 0
	27	#define DEBUGP printk
	28	#else
	29	#define DEBUGP(format, args...)
	30	#endif
	31
	32	static int
	33	check(const char *tablename,
2e4e6a17	34	const void *e,
c4986734	35	const struct xt_target *target,
1da177e4 LT	36	void *targinfo,
	37	unsigned int targinfosize,
	38	unsigned int hook_mask)
	39	{
	40	const struct ip_nat_multi_range_compat *mr = targinfo;
	41
1da177e4 LT	42	if (!(mr->range[0].flags & IP_NAT_RANGE_MAP_IPS)) {
	43	DEBUGP(MODULENAME":check: bad MAP_IPS.\n");
	44	return 0;
	45	}
	46	if (mr->rangesize != 1) {
	47	DEBUGP(MODULENAME":check: bad rangesize %u.\n", mr->rangesize);
	48	return 0;
	49	}
	50	return 1;
	51	}
	52
	53	static unsigned int
	54	target(struct sk_buff **pskb,
	55	const struct net_device *in,
	56	const struct net_device *out,
	57	unsigned int hooknum,
c4986734	58	const struct xt_target *target,
1da177e4 LT	59	const void *targinfo,
	60	void *userinfo)
	61	{
	62	struct ip_conntrack *ct;
	63	enum ip_conntrack_info ctinfo;
	64	u_int32_t new_ip, netmask;
	65	const struct ip_nat_multi_range_compat *mr = targinfo;
	66	struct ip_nat_range newrange;
	67
	68	IP_NF_ASSERT(hooknum == NF_IP_PRE_ROUTING
000efe1d GWS	69	\|\| hooknum == NF_IP_POST_ROUTING
000efe1d GWS	70	\|\| hooknum == NF_IP_LOCAL_OUT);
1da177e4 LT	71	ct = ip_conntrack_get(*pskb, &ctinfo);
	72
	73	netmask = ~(mr->range[0].min_ip ^ mr->range[0].max_ip);
	74
000efe1d	75	if (hooknum == NF_IP_PRE_ROUTING \|\| hooknum == NF_IP_LOCAL_OUT)
1da177e4 LT	76	new_ip = (*pskb)->nh.iph->daddr & ~netmask;
	77	else
	78	new_ip = (*pskb)->nh.iph->saddr & ~netmask;
	79	new_ip \|= mr->range[0].min_ip & netmask;
	80
	81	newrange = ((struct ip_nat_range)
	82	{ mr->range[0].flags \| IP_NAT_RANGE_MAP_IPS,
	83	new_ip, new_ip,
	84	mr->range[0].min, mr->range[0].max });
	85
	86	/* Hand modified range to generic setup. */
	87	return ip_nat_setup_info(ct, &newrange, hooknum);
	88	}
	89
	90	static struct ipt_target target_module = {
	91	.name = MODULENAME,
	92	.target = target,
1d5cd909 PM	93	.targetsize = sizeof(struct ip_nat_multi_range_compat),
	94	.table = "nat",
	95	.hooks = (1 << NF_IP_PRE_ROUTING) \| (1 << NF_IP_POST_ROUTING) \|
	96	(1 << NF_IP_LOCAL_OUT),
1da177e4 LT	97	.checkentry = check,
	98	.me = THIS_MODULE
	99	};
	100
	101	static int __init init(void)
	102	{
	103	return ipt_register_target(&target_module);
	104	}
	105
	106	static void __exit fini(void)
	107	{
	108	ipt_unregister_target(&target_module);
	109	}
	110
	111	module_init(init);
	112	module_exit(fini);