[net-next-2.6.git] / net / ipv4 / netfilter / ip_nat_standalone.c

/* This file contains all the functions required for the standalone
   ip_nat module.

   These are not required by the compatibility layer.
*/

/* (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.
 */

/*
 * 23 Apr 2001: Harald Welte <laforge@gnumonks.org>
 * 	- new API and handling of conntrack/nat helpers
 * 	- now capable of multiple expectations for one master
 * */

#include <linux/config.h>
#include <linux/types.h>
#include <linux/icmp.h>
#include <linux/ip.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <net/ip.h>
#include <net/checksum.h>
#include <linux/spinlock.h>

#define ASSERT_READ_LOCK(x)
#define ASSERT_WRITE_LOCK(x)

#include <linux/netfilter_ipv4/ip_nat.h>
#include <linux/netfilter_ipv4/ip_nat_rule.h>
#include <linux/netfilter_ipv4/ip_nat_protocol.h>
#include <linux/netfilter_ipv4/ip_nat_core.h>
#include <linux/netfilter_ipv4/ip_nat_helper.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ip_conntrack_core.h>
#include <linux/netfilter_ipv4/listhelp.h>

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

#define HOOKNAME(hooknum) ((hooknum) == NF_IP_POST_ROUTING ? "POST_ROUTING"  \
			   : ((hooknum) == NF_IP_PRE_ROUTING ? "PRE_ROUTING" \
			      : ((hooknum) == NF_IP_LOCAL_OUT ? "LOCAL_OUT"  \
			         : ((hooknum) == NF_IP_LOCAL_IN ? "LOCAL_IN"  \
				    : "*ERROR*")))

static unsigned int
ip_nat_fn(unsigned int hooknum,
	  struct sk_buff **pskb,
	  const struct net_device *in,
	  const struct net_device *out,
	  int (*okfn)(struct sk_buff *))
{
	struct ip_conntrack *ct;
	enum ip_conntrack_info ctinfo;
	struct ip_nat_info *info;
	/* maniptype == SRC for postrouting. */
	enum ip_nat_manip_type maniptype = HOOK2MANIP(hooknum);

	/* We never see fragments: conntrack defrags on pre-routing
	   and local-out, and ip_nat_out protects post-routing. */
	IP_NF_ASSERT(!((*pskb)->nh.iph->frag_off
		       & htons(IP_MF|IP_OFFSET)));

	/* If we had a hardware checksum before, it's now invalid */
	if ((*pskb)->ip_summed == CHECKSUM_HW)
		if (skb_checksum_help(*pskb, (out == NULL)))
			return NF_DROP;

	ct = ip_conntrack_get(*pskb, &ctinfo);
	/* Can't track?  It's not due to stress, or conntrack would
	   have dropped it.  Hence it's the user's responsibilty to
	   packet filter it out, or implement conntrack/NAT for that
	   protocol. 8) --RR */
	if (!ct) {
		/* Exception: ICMP redirect to new connection (not in
                   hash table yet).  We must not let this through, in
                   case we're doing NAT to the same network. */
		if ((*pskb)->nh.iph->protocol == IPPROTO_ICMP) {
			struct icmphdr _hdr, *hp;

			hp = skb_header_pointer(*pskb,
						(*pskb)->nh.iph->ihl*4,
						sizeof(_hdr), &_hdr);
			if (hp != NULL &&
			    hp->type == ICMP_REDIRECT)
				return NF_DROP;
		}
		return NF_ACCEPT;
	}

	/* Don't try to NAT if this packet is not conntracked */
	if (ct == &ip_conntrack_untracked)
		return NF_ACCEPT;

	switch (ctinfo) {
	case IP_CT_RELATED:
	case IP_CT_RELATED+IP_CT_IS_REPLY:
		if ((*pskb)->nh.iph->protocol == IPPROTO_ICMP) {
			if (!ip_nat_icmp_reply_translation(pskb, ct, maniptype,
							   CTINFO2DIR(ctinfo)))
				return NF_DROP;
			else
				return NF_ACCEPT;
		}
		/* Fall thru... (Only ICMPs can be IP_CT_IS_REPLY) */
	case IP_CT_NEW:
		info = &ct->nat.info;

		/* Seen it before?  This can happen for loopback, retrans,
		   or local packets.. */
		if (!ip_nat_initialized(ct, maniptype)) {
			unsigned int ret;

			if (unlikely(is_confirmed(ct)))
				/* NAT module was loaded late */
				ret = alloc_null_binding_confirmed(ct, info,
				                                   hooknum);
			else if (hooknum == NF_IP_LOCAL_IN)
				/* LOCAL_IN hook doesn't have a chain!  */
				ret = alloc_null_binding(ct, info, hooknum);
			else
				ret = ip_nat_rule_find(pskb, hooknum,
						       in, out, ct,
						       info);

			if (ret != NF_ACCEPT) {
				return ret;
			}
		} else
			DEBUGP("Already setup manip %s for ct %p\n",
			       maniptype == IP_NAT_MANIP_SRC ? "SRC" : "DST",
			       ct);
		break;

	default:
		/* ESTABLISHED */
		IP_NF_ASSERT(ctinfo == IP_CT_ESTABLISHED
			     || ctinfo == (IP_CT_ESTABLISHED+IP_CT_IS_REPLY));
		info = &ct->nat.info;
	}

	IP_NF_ASSERT(info);
	return ip_nat_packet(ct, ctinfo, hooknum, pskb);
}

static unsigned int
ip_nat_in(unsigned int hooknum,
          struct sk_buff **pskb,
          const struct net_device *in,
          const struct net_device *out,
          int (*okfn)(struct sk_buff *))
{
	struct ip_conntrack *ct;
	enum ip_conntrack_info ctinfo;
	unsigned int ret;

	ret = ip_nat_fn(hooknum, pskb, in, out, okfn);
	if (ret != NF_DROP && ret != NF_STOLEN
	    && (ct = ip_conntrack_get(*pskb, &ctinfo)) != NULL) {
		enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);

		if (ct->tuplehash[dir].tuple.src.ip !=
		    ct->tuplehash[!dir].tuple.dst.ip) {
			dst_release((*pskb)->dst);
			(*pskb)->dst = NULL;
		}
	}
	return ret;
}

static unsigned int
ip_nat_out(unsigned int hooknum,
	   struct sk_buff **pskb,
	   const struct net_device *in,
	   const struct net_device *out,
	   int (*okfn)(struct sk_buff *))
{
	struct ip_conntrack *ct;
	enum ip_conntrack_info ctinfo;
	unsigned int ret;

	/* root is playing with raw sockets. */
	if ((*pskb)->len < sizeof(struct iphdr)
	    || (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr))
		return NF_ACCEPT;

	ret = ip_nat_fn(hooknum, pskb, in, out, okfn);
	if (ret != NF_DROP && ret != NF_STOLEN
	    && (ct = ip_conntrack_get(*pskb, &ctinfo)) != NULL) {
		enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);

		if (ct->tuplehash[dir].tuple.src.ip !=
		    ct->tuplehash[!dir].tuple.dst.ip
#ifdef CONFIG_XFRM
		    || ct->tuplehash[dir].tuple.src.u.all !=
		       ct->tuplehash[!dir].tuple.dst.u.all
#endif
		    )
			return ip_route_me_harder(pskb) == 0 ? ret : NF_DROP;
	}
	return ret;
}

static unsigned int
ip_nat_local_fn(unsigned int hooknum,
		struct sk_buff **pskb,
		const struct net_device *in,
		const struct net_device *out,
		int (*okfn)(struct sk_buff *))
{
	struct ip_conntrack *ct;
	enum ip_conntrack_info ctinfo;
	unsigned int ret;

	/* root is playing with raw sockets. */
	if ((*pskb)->len < sizeof(struct iphdr)
	    || (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr))
		return NF_ACCEPT;

	ret = ip_nat_fn(hooknum, pskb, in, out, okfn);
	if (ret != NF_DROP && ret != NF_STOLEN
	    && (ct = ip_conntrack_get(*pskb, &ctinfo)) != NULL) {
		enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);

		if (ct->tuplehash[dir].tuple.dst.ip !=
		    ct->tuplehash[!dir].tuple.src.ip
#ifdef CONFIG_XFRM
		    || ct->tuplehash[dir].tuple.dst.u.all !=
		       ct->tuplehash[dir].tuple.src.u.all
#endif
		    )
			return ip_route_me_harder(pskb) == 0 ? ret : NF_DROP;
	}
	return ret;
}

static unsigned int
ip_nat_adjust(unsigned int hooknum,
	      struct sk_buff **pskb,
	      const struct net_device *in,
	      const struct net_device *out,
	      int (*okfn)(struct sk_buff *))
{
	struct ip_conntrack *ct;
	enum ip_conntrack_info ctinfo;

	ct = ip_conntrack_get(*pskb, &ctinfo);
	if (ct && test_bit(IPS_SEQ_ADJUST_BIT, &ct->status)) {
	        DEBUGP("ip_nat_standalone: adjusting sequence number\n");
	        if (!ip_nat_seq_adjust(pskb, ct, ctinfo))
	                return NF_DROP;
	}
	return NF_ACCEPT;
}

/* We must be after connection tracking and before packet filtering. */

/* Before packet filtering, change destination */
static struct nf_hook_ops ip_nat_in_ops = {
	.hook		= ip_nat_in,
	.owner		= THIS_MODULE,
	.pf		= PF_INET,
	.hooknum	= NF_IP_PRE_ROUTING,
	.priority	= NF_IP_PRI_NAT_DST,
};

/* After packet filtering, change source */
static struct nf_hook_ops ip_nat_out_ops = {
	.hook		= ip_nat_out,
	.owner		= THIS_MODULE,
	.pf		= PF_INET,
	.hooknum	= NF_IP_POST_ROUTING,
	.priority	= NF_IP_PRI_NAT_SRC,
};

/* After conntrack, adjust sequence number */
static struct nf_hook_ops ip_nat_adjust_out_ops = {
	.hook		= ip_nat_adjust,
	.owner		= THIS_MODULE,
	.pf		= PF_INET,
	.hooknum	= NF_IP_POST_ROUTING,
	.priority	= NF_IP_PRI_NAT_SEQ_ADJUST,
};

/* Before packet filtering, change destination */
static struct nf_hook_ops ip_nat_local_out_ops = {
	.hook		= ip_nat_local_fn,
	.owner		= THIS_MODULE,
	.pf		= PF_INET,
	.hooknum	= NF_IP_LOCAL_OUT,
	.priority	= NF_IP_PRI_NAT_DST,
};

/* After packet filtering, change source for reply packets of LOCAL_OUT DNAT */
static struct nf_hook_ops ip_nat_local_in_ops = {
	.hook		= ip_nat_fn,
	.owner		= THIS_MODULE,
	.pf		= PF_INET,
	.hooknum	= NF_IP_LOCAL_IN,
	.priority	= NF_IP_PRI_NAT_SRC,
};

/* After conntrack, adjust sequence number */
static struct nf_hook_ops ip_nat_adjust_in_ops = {
	.hook		= ip_nat_adjust,
	.owner		= THIS_MODULE,
	.pf		= PF_INET,
	.hooknum	= NF_IP_LOCAL_IN,
	.priority	= NF_IP_PRI_NAT_SEQ_ADJUST,
};


static int init_or_cleanup(int init)
{
	int ret = 0;

	need_ip_conntrack();

	if (!init) goto cleanup;

	ret = ip_nat_rule_init();
	if (ret < 0) {
		printk("ip_nat_init: can't setup rules.\n");
		goto cleanup_nothing;
	}
	ret = nf_register_hook(&ip_nat_in_ops);
	if (ret < 0) {
		printk("ip_nat_init: can't register in hook.\n");
		goto cleanup_rule_init;
	}
	ret = nf_register_hook(&ip_nat_out_ops);
	if (ret < 0) {
		printk("ip_nat_init: can't register out hook.\n");
		goto cleanup_inops;
	}
	ret = nf_register_hook(&ip_nat_adjust_in_ops);
	if (ret < 0) {
		printk("ip_nat_init: can't register adjust in hook.\n");
		goto cleanup_outops;
	}
	ret = nf_register_hook(&ip_nat_adjust_out_ops);
	if (ret < 0) {
		printk("ip_nat_init: can't register adjust out hook.\n");
		goto cleanup_adjustin_ops;
	}
	ret = nf_register_hook(&ip_nat_local_out_ops);
	if (ret < 0) {
		printk("ip_nat_init: can't register local out hook.\n");
		goto cleanup_adjustout_ops;;
	}
	ret = nf_register_hook(&ip_nat_local_in_ops);
	if (ret < 0) {
		printk("ip_nat_init: can't register local in hook.\n");
		goto cleanup_localoutops;
	}
	return ret;

 cleanup:
	nf_unregister_hook(&ip_nat_local_in_ops);
 cleanup_localoutops:
	nf_unregister_hook(&ip_nat_local_out_ops);
 cleanup_adjustout_ops:
	nf_unregister_hook(&ip_nat_adjust_out_ops);
 cleanup_adjustin_ops:
	nf_unregister_hook(&ip_nat_adjust_in_ops);
 cleanup_outops:
	nf_unregister_hook(&ip_nat_out_ops);
 cleanup_inops:
	nf_unregister_hook(&ip_nat_in_ops);
 cleanup_rule_init:
	ip_nat_rule_cleanup();
 cleanup_nothing:
	return ret;
}

static int __init init(void)
{
	return init_or_cleanup(1);
}

static void __exit fini(void)
{
	init_or_cleanup(0);
}

module_init(init);
module_exit(fini);

MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/* This file contains all the functions required for the standalone
	2	ip_nat module.
	3
	4	These are not required by the compatibility layer.
	5	*/
	6
	7	/* (C) 1999-2001 Paul `Rusty' Russell
	8	* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
	9	*
	10	* This program is free software; you can redistribute it and/or modify
	11	* it under the terms of the GNU General Public License version 2 as
	12	* published by the Free Software Foundation.
	13	*/
	14
	15	/*
	16	* 23 Apr 2001: Harald Welte <laforge@gnumonks.org>
	17	* - new API and handling of conntrack/nat helpers
	18	* - now capable of multiple expectations for one master
	19	* */
	20
	21	#include <linux/config.h>
	22	#include <linux/types.h>
	23	#include <linux/icmp.h>
	24	#include <linux/ip.h>
	25	#include <linux/netfilter.h>
	26	#include <linux/netfilter_ipv4.h>
	27	#include <linux/module.h>
	28	#include <linux/skbuff.h>
	29	#include <linux/proc_fs.h>
	30	#include <net/ip.h>
	31	#include <net/checksum.h>
	32	#include <linux/spinlock.h>
	33
e45b1be8 PM	34	#define ASSERT_READ_LOCK(x)
e45b1be8 PM	35	#define ASSERT_WRITE_LOCK(x)
1da177e4 LT	36
	37	#include <linux/netfilter_ipv4/ip_nat.h>
	38	#include <linux/netfilter_ipv4/ip_nat_rule.h>
	39	#include <linux/netfilter_ipv4/ip_nat_protocol.h>
	40	#include <linux/netfilter_ipv4/ip_nat_core.h>
	41	#include <linux/netfilter_ipv4/ip_nat_helper.h>
	42	#include <linux/netfilter_ipv4/ip_tables.h>
	43	#include <linux/netfilter_ipv4/ip_conntrack_core.h>
	44	#include <linux/netfilter_ipv4/listhelp.h>
	45
	46	#if 0
	47	#define DEBUGP printk
	48	#else
	49	#define DEBUGP(format, args...)
	50	#endif
	51
	52	#define HOOKNAME(hooknum) ((hooknum) == NF_IP_POST_ROUTING ? "POST_ROUTING" \
	53	: ((hooknum) == NF_IP_PRE_ROUTING ? "PRE_ROUTING" \
	54	: ((hooknum) == NF_IP_LOCAL_OUT ? "LOCAL_OUT" \
	55	: ((hooknum) == NF_IP_LOCAL_IN ? "LOCAL_IN" \
	56	: "ERROR")))
	57
	58	static unsigned int
	59	ip_nat_fn(unsigned int hooknum,
	60	struct sk_buff **pskb,
	61	const struct net_device *in,
	62	const struct net_device *out,
	63	int (okfn)(struct sk_buff ))
	64	{
	65	struct ip_conntrack *ct;
	66	enum ip_conntrack_info ctinfo;
	67	struct ip_nat_info *info;
	68	/* maniptype == SRC for postrouting. */
	69	enum ip_nat_manip_type maniptype = HOOK2MANIP(hooknum);
	70
	71	/* We never see fragments: conntrack defrags on pre-routing
	72	and local-out, and ip_nat_out protects post-routing. */
	73	IP_NF_ASSERT(!((*pskb)->nh.iph->frag_off
	74	& htons(IP_MF\|IP_OFFSET)));
	75
1da177e4 LT	76	/* If we had a hardware checksum before, it's now invalid */
	77	if ((*pskb)->ip_summed == CHECKSUM_HW)
	78	if (skb_checksum_help(*pskb, (out == NULL)))
	79	return NF_DROP;
	80
	81	ct = ip_conntrack_get(*pskb, &ctinfo);
	82	/* Can't track? It's not due to stress, or conntrack would
	83	have dropped it. Hence it's the user's responsibilty to
	84	packet filter it out, or implement conntrack/NAT for that
	85	protocol. 8) --RR */
	86	if (!ct) {
	87	/* Exception: ICMP redirect to new connection (not in
	88	hash table yet). We must not let this through, in
	89	case we're doing NAT to the same network. */
	90	if ((*pskb)->nh.iph->protocol == IPPROTO_ICMP) {
	91	struct icmphdr _hdr, *hp;
	92
	93	hp = skb_header_pointer(*pskb,
	94	(pskb)->nh.iph->ihl4,
	95	sizeof(_hdr), &_hdr);
	96	if (hp != NULL &&
	97	hp->type == ICMP_REDIRECT)
	98	return NF_DROP;
	99	}
	100	return NF_ACCEPT;
	101	}
	102
8b83bc77 HW	103	/* Don't try to NAT if this packet is not conntracked */
	104	if (ct == &ip_conntrack_untracked)
	105	return NF_ACCEPT;
	106
1da177e4 LT	107	switch (ctinfo) {
	108	case IP_CT_RELATED:
	109	case IP_CT_RELATED+IP_CT_IS_REPLY:
	110	if ((*pskb)->nh.iph->protocol == IPPROTO_ICMP) {
188bab3a HW	111	if (!ip_nat_icmp_reply_translation(pskb, ct, maniptype,
188bab3a HW	112	CTINFO2DIR(ctinfo)))
1da177e4 LT	113	return NF_DROP;
	114	else
	115	return NF_ACCEPT;
	116	}
	117	/* Fall thru... (Only ICMPs can be IP_CT_IS_REPLY) */
	118	case IP_CT_NEW:
	119	info = &ct->nat.info;
	120
	121	/* Seen it before? This can happen for loopback, retrans,
	122	or local packets.. */
	123	if (!ip_nat_initialized(ct, maniptype)) {
	124	unsigned int ret;
	125
03486a4f PM	126	if (unlikely(is_confirmed(ct)))
	127	/* NAT module was loaded late */
	128	ret = alloc_null_binding_confirmed(ct, info,
	129	hooknum);
	130	else if (hooknum == NF_IP_LOCAL_IN)
	131	/* LOCAL_IN hook doesn't have a chain! */
1da177e4 LT	132	ret = alloc_null_binding(ct, info, hooknum);
	133	else
	134	ret = ip_nat_rule_find(pskb, hooknum,
	135	in, out, ct,
	136	info);
	137
	138	if (ret != NF_ACCEPT) {
	139	return ret;
	140	}
	141	} else
	142	DEBUGP("Already setup manip %s for ct %p\n",
	143	maniptype == IP_NAT_MANIP_SRC ? "SRC" : "DST",
	144	ct);
	145	break;
	146
	147	default:
	148	/* ESTABLISHED */
	149	IP_NF_ASSERT(ctinfo == IP_CT_ESTABLISHED
	150	\|\| ctinfo == (IP_CT_ESTABLISHED+IP_CT_IS_REPLY));
	151	info = &ct->nat.info;
	152	}
	153
	154	IP_NF_ASSERT(info);
188bab3a	155	return ip_nat_packet(ct, ctinfo, hooknum, pskb);
1da177e4 LT	156	}
	157
	158	static unsigned int
	159	ip_nat_in(unsigned int hooknum,
	160	struct sk_buff **pskb,
	161	const struct net_device *in,
	162	const struct net_device *out,
	163	int (okfn)(struct sk_buff ))
	164	{
4e8e9de7 PM	165	struct ip_conntrack *ct;
4e8e9de7 PM	166	enum ip_conntrack_info ctinfo;
1da177e4 LT	167	unsigned int ret;
1da177e4 LT	168
1da177e4 LT	169	ret = ip_nat_fn(hooknum, pskb, in, out, okfn);
1da177e4 LT	170	if (ret != NF_DROP && ret != NF_STOLEN
4e8e9de7 PM	171	&& (ct = ip_conntrack_get(*pskb, &ctinfo)) != NULL) {
	172	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
	173
	174	if (ct->tuplehash[dir].tuple.src.ip !=
	175	ct->tuplehash[!dir].tuple.dst.ip) {
	176	dst_release((*pskb)->dst);
	177	(*pskb)->dst = NULL;
	178	}
1da177e4 LT	179	}
	180	return ret;
	181	}
	182
	183	static unsigned int
	184	ip_nat_out(unsigned int hooknum,
	185	struct sk_buff **pskb,
	186	const struct net_device *in,
	187	const struct net_device *out,
	188	int (okfn)(struct sk_buff ))
	189	{
5c901daa PM	190	struct ip_conntrack *ct;
	191	enum ip_conntrack_info ctinfo;
	192	unsigned int ret;
	193
1da177e4 LT	194	/* root is playing with raw sockets. */
	195	if ((*pskb)->len < sizeof(struct iphdr)
	196	\|\| (pskb)->nh.iph->ihl 4 < sizeof(struct iphdr))
	197	return NF_ACCEPT;
	198
5c901daa PM	199	ret = ip_nat_fn(hooknum, pskb, in, out, okfn);
	200	if (ret != NF_DROP && ret != NF_STOLEN
	201	&& (ct = ip_conntrack_get(*pskb, &ctinfo)) != NULL) {
	202	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
	203
	204	if (ct->tuplehash[dir].tuple.src.ip !=
	205	ct->tuplehash[!dir].tuple.dst.ip
	206	#ifdef CONFIG_XFRM
	207	\|\| ct->tuplehash[dir].tuple.src.u.all !=
	208	ct->tuplehash[!dir].tuple.dst.u.all
	209	#endif
	210	)
	211	return ip_route_me_harder(pskb) == 0 ? ret : NF_DROP;
	212	}
	213	return ret;
1da177e4 LT	214	}
	215
	216	static unsigned int
	217	ip_nat_local_fn(unsigned int hooknum,
	218	struct sk_buff **pskb,
	219	const struct net_device *in,
	220	const struct net_device *out,
	221	int (okfn)(struct sk_buff ))
	222	{
4e8e9de7 PM	223	struct ip_conntrack *ct;
4e8e9de7 PM	224	enum ip_conntrack_info ctinfo;
1da177e4 LT	225	unsigned int ret;
	226
	227	/* root is playing with raw sockets. */
	228	if ((*pskb)->len < sizeof(struct iphdr)
	229	\|\| (pskb)->nh.iph->ihl 4 < sizeof(struct iphdr))
	230	return NF_ACCEPT;
	231
1da177e4 LT	232	ret = ip_nat_fn(hooknum, pskb, in, out, okfn);
1da177e4 LT	233	if (ret != NF_DROP && ret != NF_STOLEN
4e8e9de7 PM	234	&& (ct = ip_conntrack_get(*pskb, &ctinfo)) != NULL) {
	235	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
	236
	237	if (ct->tuplehash[dir].tuple.dst.ip !=
5c901daa PM	238	ct->tuplehash[!dir].tuple.src.ip
	239	#ifdef CONFIG_XFRM
	240	\|\| ct->tuplehash[dir].tuple.dst.u.all !=
	241	ct->tuplehash[dir].tuple.src.u.all
	242	#endif
	243	)
4e8e9de7 PM	244	return ip_route_me_harder(pskb) == 0 ? ret : NF_DROP;
4e8e9de7 PM	245	}
1da177e4 LT	246	return ret;
	247	}
	248
e281e3ac PM	249	static unsigned int
	250	ip_nat_adjust(unsigned int hooknum,
	251	struct sk_buff **pskb,
	252	const struct net_device *in,
	253	const struct net_device *out,
	254	int (okfn)(struct sk_buff ))
	255	{
	256	struct ip_conntrack *ct;
	257	enum ip_conntrack_info ctinfo;
	258
	259	ct = ip_conntrack_get(*pskb, &ctinfo);
	260	if (ct && test_bit(IPS_SEQ_ADJUST_BIT, &ct->status)) {
	261	DEBUGP("ip_nat_standalone: adjusting sequence number\n");
	262	if (!ip_nat_seq_adjust(pskb, ct, ctinfo))
	263	return NF_DROP;
	264	}
	265	return NF_ACCEPT;
	266	}
	267
1da177e4 LT	268	/* We must be after connection tracking and before packet filtering. */
	269
	270	/* Before packet filtering, change destination */
	271	static struct nf_hook_ops ip_nat_in_ops = {
	272	.hook = ip_nat_in,
	273	.owner = THIS_MODULE,
	274	.pf = PF_INET,
	275	.hooknum = NF_IP_PRE_ROUTING,
	276	.priority = NF_IP_PRI_NAT_DST,
	277	};
	278
	279	/* After packet filtering, change source */
	280	static struct nf_hook_ops ip_nat_out_ops = {
	281	.hook = ip_nat_out,
	282	.owner = THIS_MODULE,
	283	.pf = PF_INET,
	284	.hooknum = NF_IP_POST_ROUTING,
	285	.priority = NF_IP_PRI_NAT_SRC,
	286	};
	287
e281e3ac PM	288	/* After conntrack, adjust sequence number */
	289	static struct nf_hook_ops ip_nat_adjust_out_ops = {
	290	.hook = ip_nat_adjust,
	291	.owner = THIS_MODULE,
	292	.pf = PF_INET,
	293	.hooknum = NF_IP_POST_ROUTING,
	294	.priority = NF_IP_PRI_NAT_SEQ_ADJUST,
	295	};
	296
1da177e4 LT	297	/* Before packet filtering, change destination */
	298	static struct nf_hook_ops ip_nat_local_out_ops = {
	299	.hook = ip_nat_local_fn,
	300	.owner = THIS_MODULE,
	301	.pf = PF_INET,
	302	.hooknum = NF_IP_LOCAL_OUT,
	303	.priority = NF_IP_PRI_NAT_DST,
	304	};
	305
	306	/* After packet filtering, change source for reply packets of LOCAL_OUT DNAT */
	307	static struct nf_hook_ops ip_nat_local_in_ops = {
	308	.hook = ip_nat_fn,
	309	.owner = THIS_MODULE,
	310	.pf = PF_INET,
	311	.hooknum = NF_IP_LOCAL_IN,
	312	.priority = NF_IP_PRI_NAT_SRC,
	313	};
	314
e281e3ac PM	315	/* After conntrack, adjust sequence number */
	316	static struct nf_hook_ops ip_nat_adjust_in_ops = {
	317	.hook = ip_nat_adjust,
	318	.owner = THIS_MODULE,
	319	.pf = PF_INET,
	320	.hooknum = NF_IP_LOCAL_IN,
	321	.priority = NF_IP_PRI_NAT_SEQ_ADJUST,
	322	};
	323
	324
1da177e4 LT	325	static int init_or_cleanup(int init)
	326	{
	327	int ret = 0;
	328
	329	need_ip_conntrack();
	330
	331	if (!init) goto cleanup;
	332
	333	ret = ip_nat_rule_init();
	334	if (ret < 0) {
	335	printk("ip_nat_init: can't setup rules.\n");
	336	goto cleanup_nothing;
	337	}
1da177e4 LT	338	ret = nf_register_hook(&ip_nat_in_ops);
	339	if (ret < 0) {
	340	printk("ip_nat_init: can't register in hook.\n");
188bab3a	341	goto cleanup_rule_init;
1da177e4 LT	342	}
	343	ret = nf_register_hook(&ip_nat_out_ops);
	344	if (ret < 0) {
	345	printk("ip_nat_init: can't register out hook.\n");
	346	goto cleanup_inops;
	347	}
e281e3ac PM	348	ret = nf_register_hook(&ip_nat_adjust_in_ops);
	349	if (ret < 0) {
	350	printk("ip_nat_init: can't register adjust in hook.\n");
	351	goto cleanup_outops;
	352	}
	353	ret = nf_register_hook(&ip_nat_adjust_out_ops);
	354	if (ret < 0) {
	355	printk("ip_nat_init: can't register adjust out hook.\n");
	356	goto cleanup_adjustin_ops;
	357	}
1da177e4 LT	358	ret = nf_register_hook(&ip_nat_local_out_ops);
	359	if (ret < 0) {
	360	printk("ip_nat_init: can't register local out hook.\n");
e281e3ac	361	goto cleanup_adjustout_ops;;
1da177e4 LT	362	}
	363	ret = nf_register_hook(&ip_nat_local_in_ops);
	364	if (ret < 0) {
	365	printk("ip_nat_init: can't register local in hook.\n");
	366	goto cleanup_localoutops;
	367	}
	368	return ret;
	369
	370	cleanup:
	371	nf_unregister_hook(&ip_nat_local_in_ops);
	372	cleanup_localoutops:
	373	nf_unregister_hook(&ip_nat_local_out_ops);
e281e3ac PM	374	cleanup_adjustout_ops:
	375	nf_unregister_hook(&ip_nat_adjust_out_ops);
	376	cleanup_adjustin_ops:
	377	nf_unregister_hook(&ip_nat_adjust_in_ops);
1da177e4 LT	378	cleanup_outops:
	379	nf_unregister_hook(&ip_nat_out_ops);
	380	cleanup_inops:
	381	nf_unregister_hook(&ip_nat_in_ops);
1da177e4 LT	382	cleanup_rule_init:
	383	ip_nat_rule_cleanup();
	384	cleanup_nothing:
1da177e4 LT	385	return ret;
	386	}
	387
	388	static int __init init(void)
	389	{
	390	return init_or_cleanup(1);
	391	}
	392
	393	static void __exit fini(void)
	394	{
	395	init_or_cleanup(0);
	396	}
	397
	398	module_init(init);
	399	module_exit(fini);
	400
1da177e4	401	MODULE_LICENSE("GPL");