[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 *))
{
	u_int32_t saddr, daddr;
	unsigned int ret;

	saddr = (*pskb)->nh.iph->saddr;
	daddr = (*pskb)->nh.iph->daddr;

	ret = ip_nat_fn(hooknum, pskb, in, out, okfn);
	if (ret != NF_DROP && ret != NF_STOLEN
	    && ((*pskb)->nh.iph->saddr != saddr
	        || (*pskb)->nh.iph->daddr != daddr)) {
		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 *))
{
	/* root is playing with raw sockets. */
	if ((*pskb)->len < sizeof(struct iphdr)
	    || (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr))
		return NF_ACCEPT;

	return ip_nat_fn(hooknum, pskb, in, out, okfn);
}

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 *))
{
	u_int32_t saddr, daddr;
	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;

	saddr = (*pskb)->nh.iph->saddr;
	daddr = (*pskb)->nh.iph->daddr;

	ret = ip_nat_fn(hooknum, pskb, in, out, okfn);
	if (ret != NF_DROP && ret != NF_STOLEN
	    && ((*pskb)->nh.iph->saddr != saddr
		|| (*pskb)->nh.iph->daddr != daddr))
		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	{
	165	u_int32_t saddr, daddr;
	166	unsigned int ret;
	167
	168	saddr = (*pskb)->nh.iph->saddr;
	169	daddr = (*pskb)->nh.iph->daddr;
	170
	171	ret = ip_nat_fn(hooknum, pskb, in, out, okfn);
	172	if (ret != NF_DROP && ret != NF_STOLEN
	173	&& ((*pskb)->nh.iph->saddr != saddr
	174	\|\| (*pskb)->nh.iph->daddr != daddr)) {
	175	dst_release((*pskb)->dst);
	176	(*pskb)->dst = NULL;
	177	}
	178	return ret;
	179	}
	180
	181	static unsigned int
	182	ip_nat_out(unsigned int hooknum,
	183	struct sk_buff **pskb,
	184	const struct net_device *in,
	185	const struct net_device *out,
	186	int (okfn)(struct sk_buff ))
	187	{
	188	/* root is playing with raw sockets. */
	189	if ((*pskb)->len < sizeof(struct iphdr)
	190	\|\| (pskb)->nh.iph->ihl 4 < sizeof(struct iphdr))
	191	return NF_ACCEPT;
	192
1da177e4 LT	193	return ip_nat_fn(hooknum, pskb, in, out, okfn);
	194	}
	195
	196	static unsigned int
	197	ip_nat_local_fn(unsigned int hooknum,
	198	struct sk_buff **pskb,
	199	const struct net_device *in,
	200	const struct net_device *out,
	201	int (okfn)(struct sk_buff ))
	202	{
	203	u_int32_t saddr, daddr;
	204	unsigned int ret;
	205
	206	/* root is playing with raw sockets. */
	207	if ((*pskb)->len < sizeof(struct iphdr)
	208	\|\| (pskb)->nh.iph->ihl 4 < sizeof(struct iphdr))
	209	return NF_ACCEPT;
	210
	211	saddr = (*pskb)->nh.iph->saddr;
	212	daddr = (*pskb)->nh.iph->daddr;
	213
	214	ret = ip_nat_fn(hooknum, pskb, in, out, okfn);
	215	if (ret != NF_DROP && ret != NF_STOLEN
	216	&& ((*pskb)->nh.iph->saddr != saddr
	217	\|\| (*pskb)->nh.iph->daddr != daddr))
	218	return ip_route_me_harder(pskb) == 0 ? ret : NF_DROP;
	219	return ret;
	220	}
	221
e281e3ac PM	222	static unsigned int
	223	ip_nat_adjust(unsigned int hooknum,
	224	struct sk_buff **pskb,
	225	const struct net_device *in,
	226	const struct net_device *out,
	227	int (okfn)(struct sk_buff ))
	228	{
	229	struct ip_conntrack *ct;
	230	enum ip_conntrack_info ctinfo;
	231
	232	ct = ip_conntrack_get(*pskb, &ctinfo);
	233	if (ct && test_bit(IPS_SEQ_ADJUST_BIT, &ct->status)) {
	234	DEBUGP("ip_nat_standalone: adjusting sequence number\n");
	235	if (!ip_nat_seq_adjust(pskb, ct, ctinfo))
	236	return NF_DROP;
	237	}
	238	return NF_ACCEPT;
	239	}
	240
1da177e4 LT	241	/* We must be after connection tracking and before packet filtering. */
	242
	243	/* Before packet filtering, change destination */
	244	static struct nf_hook_ops ip_nat_in_ops = {
	245	.hook = ip_nat_in,
	246	.owner = THIS_MODULE,
	247	.pf = PF_INET,
	248	.hooknum = NF_IP_PRE_ROUTING,
	249	.priority = NF_IP_PRI_NAT_DST,
	250	};
	251
	252	/* After packet filtering, change source */
	253	static struct nf_hook_ops ip_nat_out_ops = {
	254	.hook = ip_nat_out,
	255	.owner = THIS_MODULE,
	256	.pf = PF_INET,
	257	.hooknum = NF_IP_POST_ROUTING,
	258	.priority = NF_IP_PRI_NAT_SRC,
	259	};
	260
e281e3ac PM	261	/* After conntrack, adjust sequence number */
	262	static struct nf_hook_ops ip_nat_adjust_out_ops = {
	263	.hook = ip_nat_adjust,
	264	.owner = THIS_MODULE,
	265	.pf = PF_INET,
	266	.hooknum = NF_IP_POST_ROUTING,
	267	.priority = NF_IP_PRI_NAT_SEQ_ADJUST,
	268	};
	269
1da177e4 LT	270	/* Before packet filtering, change destination */
	271	static struct nf_hook_ops ip_nat_local_out_ops = {
	272	.hook = ip_nat_local_fn,
	273	.owner = THIS_MODULE,
	274	.pf = PF_INET,
	275	.hooknum = NF_IP_LOCAL_OUT,
	276	.priority = NF_IP_PRI_NAT_DST,
	277	};
	278
	279	/* After packet filtering, change source for reply packets of LOCAL_OUT DNAT */
	280	static struct nf_hook_ops ip_nat_local_in_ops = {
	281	.hook = ip_nat_fn,
	282	.owner = THIS_MODULE,
	283	.pf = PF_INET,
	284	.hooknum = NF_IP_LOCAL_IN,
	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_in_ops = {
	290	.hook = ip_nat_adjust,
	291	.owner = THIS_MODULE,
	292	.pf = PF_INET,
	293	.hooknum = NF_IP_LOCAL_IN,
	294	.priority = NF_IP_PRI_NAT_SEQ_ADJUST,
	295	};
	296
	297
1da177e4 LT	298	static int init_or_cleanup(int init)
	299	{
	300	int ret = 0;
	301
	302	need_ip_conntrack();
	303
	304	if (!init) goto cleanup;
	305
	306	ret = ip_nat_rule_init();
	307	if (ret < 0) {
	308	printk("ip_nat_init: can't setup rules.\n");
	309	goto cleanup_nothing;
	310	}
1da177e4 LT	311	ret = nf_register_hook(&ip_nat_in_ops);
	312	if (ret < 0) {
	313	printk("ip_nat_init: can't register in hook.\n");
188bab3a	314	goto cleanup_rule_init;
1da177e4 LT	315	}
	316	ret = nf_register_hook(&ip_nat_out_ops);
	317	if (ret < 0) {
	318	printk("ip_nat_init: can't register out hook.\n");
	319	goto cleanup_inops;
	320	}
e281e3ac PM	321	ret = nf_register_hook(&ip_nat_adjust_in_ops);
	322	if (ret < 0) {
	323	printk("ip_nat_init: can't register adjust in hook.\n");
	324	goto cleanup_outops;
	325	}
	326	ret = nf_register_hook(&ip_nat_adjust_out_ops);
	327	if (ret < 0) {
	328	printk("ip_nat_init: can't register adjust out hook.\n");
	329	goto cleanup_adjustin_ops;
	330	}
1da177e4 LT	331	ret = nf_register_hook(&ip_nat_local_out_ops);
	332	if (ret < 0) {
	333	printk("ip_nat_init: can't register local out hook.\n");
e281e3ac	334	goto cleanup_adjustout_ops;;
1da177e4 LT	335	}
	336	ret = nf_register_hook(&ip_nat_local_in_ops);
	337	if (ret < 0) {
	338	printk("ip_nat_init: can't register local in hook.\n");
	339	goto cleanup_localoutops;
	340	}
	341	return ret;
	342
	343	cleanup:
	344	nf_unregister_hook(&ip_nat_local_in_ops);
	345	cleanup_localoutops:
	346	nf_unregister_hook(&ip_nat_local_out_ops);
e281e3ac PM	347	cleanup_adjustout_ops:
	348	nf_unregister_hook(&ip_nat_adjust_out_ops);
	349	cleanup_adjustin_ops:
	350	nf_unregister_hook(&ip_nat_adjust_in_ops);
1da177e4 LT	351	cleanup_outops:
	352	nf_unregister_hook(&ip_nat_out_ops);
	353	cleanup_inops:
	354	nf_unregister_hook(&ip_nat_in_ops);
1da177e4 LT	355	cleanup_rule_init:
	356	ip_nat_rule_cleanup();
	357	cleanup_nothing:
1da177e4 LT	358	return ret;
	359	}
	360
	361	static int __init init(void)
	362	{
	363	return init_or_cleanup(1);
	364	}
	365
	366	static void __exit fini(void)
	367	{
	368	init_or_cleanup(0);
	369	}
	370
	371	module_init(init);
	372	module_exit(fini);
	373
1da177e4	374	MODULE_LICENSE("GPL");