[net-next-2.6.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.
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/ip.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter/x_tables.h>
#include <net/netfilter/nf_nat_rule.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Svenning Soerensen <svenning@post5.tele.dk>");
MODULE_DESCRIPTION("Xtables: 1:1 NAT mapping of IPv4 subnets");

static int netmap_tg_check(const struct xt_tgchk_param *par)
{
	const struct nf_nat_multi_range_compat *mr = par->targinfo;

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

static unsigned int
netmap_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
	struct nf_conn *ct;
	enum ip_conntrack_info ctinfo;
	__be32 new_ip, netmask;
	const struct nf_nat_multi_range_compat *mr = par->targinfo;
	struct nf_nat_range newrange;

	NF_CT_ASSERT(par->hooknum == NF_INET_PRE_ROUTING ||
		     par->hooknum == NF_INET_POST_ROUTING ||
		     par->hooknum == NF_INET_LOCAL_OUT);
	ct = nf_ct_get(skb, &ctinfo);

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

	if (par->hooknum == NF_INET_PRE_ROUTING ||
	    par->hooknum == NF_INET_LOCAL_OUT)
		new_ip = ip_hdr(skb)->daddr & ~netmask;
	else
		new_ip = ip_hdr(skb)->saddr & ~netmask;
	new_ip |= mr->range[0].min_ip & netmask;

	newrange = ((struct nf_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 nf_nat_setup_info(ct, &newrange, HOOK2MANIP(par->hooknum));
}

static struct xt_target netmap_tg_reg __read_mostly = {
	.name 		= "NETMAP",
	.family		= NFPROTO_IPV4,
	.target 	= netmap_tg,
	.targetsize	= sizeof(struct nf_nat_multi_range_compat),
	.table		= "nat",
	.hooks		= (1 << NF_INET_PRE_ROUTING) |
			  (1 << NF_INET_POST_ROUTING) |
			  (1 << NF_INET_LOCAL_OUT),
	.checkentry 	= netmap_tg_check,
	.me 		= THIS_MODULE
};

static int __init netmap_tg_init(void)
{
	return xt_register_target(&netmap_tg_reg);
}

static void __exit netmap_tg_exit(void)
{
	xt_unregister_target(&netmap_tg_reg);
}

module_init(netmap_tg_init);
module_exit(netmap_tg_exit);
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	*/
ff67e4e4	12	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
1da177e4 LT	13	#include <linux/ip.h>
	14	#include <linux/module.h>
	15	#include <linux/netdevice.h>
	16	#include <linux/netfilter.h>
	17	#include <linux/netfilter_ipv4.h>
6709dbbb	18	#include <linux/netfilter/x_tables.h>
5b1158e9	19	#include <net/netfilter/nf_nat_rule.h>
1da177e4	20
1da177e4 LT	21	MODULE_LICENSE("GPL");
1da177e4 LT	22	MODULE_AUTHOR("Svenning Soerensen <svenning@post5.tele.dk>");
2ae15b64	23	MODULE_DESCRIPTION("Xtables: 1:1 NAT mapping of IPv4 subnets");
1da177e4	24
135367b8	25	static int netmap_tg_check(const struct xt_tgchk_param *par)
1da177e4	26	{
af5d6dc2	27	const struct nf_nat_multi_range_compat *mr = par->targinfo;
1da177e4	28
1da177e4	29	if (!(mr->range[0].flags & IP_NAT_RANGE_MAP_IPS)) {
ff67e4e4	30	pr_debug("bad MAP_IPS.\n");
d6b00a53	31	return -EINVAL;
1da177e4 LT	32	}
1da177e4 LT	33	if (mr->rangesize != 1) {
ff67e4e4	34	pr_debug("bad rangesize %u.\n", mr->rangesize);
d6b00a53	35	return -EINVAL;
1da177e4	36	}
d6b00a53	37	return 0;
1da177e4 LT	38	}
	39
	40	static unsigned int
4b560b44	41	netmap_tg(struct sk_buff skb, const struct xt_action_param par)
1da177e4	42	{
587aa641	43	struct nf_conn *ct;
1da177e4	44	enum ip_conntrack_info ctinfo;
6a19d614	45	__be32 new_ip, netmask;
7eb35586	46	const struct nf_nat_multi_range_compat *mr = par->targinfo;
587aa641	47	struct nf_nat_range newrange;
1da177e4	48
7eb35586 JE	49	NF_CT_ASSERT(par->hooknum == NF_INET_PRE_ROUTING \|\|
	50	par->hooknum == NF_INET_POST_ROUTING \|\|
	51	par->hooknum == NF_INET_LOCAL_OUT);
3db05fea	52	ct = nf_ct_get(skb, &ctinfo);
1da177e4 LT	53
	54	netmask = ~(mr->range[0].min_ip ^ mr->range[0].max_ip);
	55
7eb35586 JE	56	if (par->hooknum == NF_INET_PRE_ROUTING \|\|
7eb35586 JE	57	par->hooknum == NF_INET_LOCAL_OUT)
3db05fea	58	new_ip = ip_hdr(skb)->daddr & ~netmask;
1da177e4	59	else
3db05fea	60	new_ip = ip_hdr(skb)->saddr & ~netmask;
1da177e4 LT	61	new_ip \|= mr->range[0].min_ip & netmask;
1da177e4 LT	62
587aa641	63	newrange = ((struct nf_nat_range)
1da177e4 LT	64	{ mr->range[0].flags \| IP_NAT_RANGE_MAP_IPS,
	65	new_ip, new_ip,
	66	mr->range[0].min, mr->range[0].max });
	67
	68	/* Hand modified range to generic setup. */
7eb35586	69	return nf_nat_setup_info(ct, &newrange, HOOK2MANIP(par->hooknum));
1da177e4 LT	70	}
1da177e4 LT	71
d3c5ee6d	72	static struct xt_target netmap_tg_reg __read_mostly = {
0d53778e	73	.name = "NETMAP",
ee999d8b	74	.family = NFPROTO_IPV4,
d3c5ee6d	75	.target = netmap_tg,
587aa641	76	.targetsize = sizeof(struct nf_nat_multi_range_compat),
1d5cd909	77	.table = "nat",
6e23ae2a PM	78	.hooks = (1 << NF_INET_PRE_ROUTING) \|
	79	(1 << NF_INET_POST_ROUTING) \|
	80	(1 << NF_INET_LOCAL_OUT),
d3c5ee6d	81	.checkentry = netmap_tg_check,
e905a9ed	82	.me = THIS_MODULE
1da177e4 LT	83	};
1da177e4 LT	84
d3c5ee6d	85	static int __init netmap_tg_init(void)
1da177e4	86	{
d3c5ee6d	87	return xt_register_target(&netmap_tg_reg);
1da177e4 LT	88	}
1da177e4 LT	89
d3c5ee6d	90	static void __exit netmap_tg_exit(void)
1da177e4	91	{
d3c5ee6d	92	xt_unregister_target(&netmap_tg_reg);
1da177e4 LT	93	}
1da177e4 LT	94
d3c5ee6d JE	95	module_init(netmap_tg_init);
d3c5ee6d JE	96	module_exit(netmap_tg_exit);