[deliverable/linux.git] / net / ipv6 / ipcomp6.c

/*
 * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173
 *
 * Copyright (C)2003 USAGI/WIDE Project
 *
 * Author	Mitsuru KANDA  <mk@linux-ipv6.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
/* 
 * [Memo]
 *
 * Outbound:
 *  The compression of IP datagram MUST be done before AH/ESP processing, 
 *  fragmentation, and the addition of Hop-by-Hop/Routing header. 
 *
 * Inbound:
 *  The decompression of IP datagram MUST be done after the reassembly, 
 *  AH/ESP processing.
 */
#include <linux/module.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/ipcomp.h>
#include <asm/scatterlist.h>
#include <asm/semaphore.h>
#include <linux/crypto.h>
#include <linux/pfkeyv2.h>
#include <linux/random.h>
#include <linux/percpu.h>
#include <linux/smp.h>
#include <linux/list.h>
#include <linux/vmalloc.h>
#include <linux/rtnetlink.h>
#include <net/icmp.h>
#include <net/ipv6.h>
#include <net/protocol.h>
#include <linux/ipv6.h>
#include <linux/icmpv6.h>
#include <linux/mutex.h>

struct ipcomp6_tfms {
	struct list_head list;
	struct crypto_tfm **tfms;
	int users;
};

static DEFINE_MUTEX(ipcomp6_resource_mutex);
static void **ipcomp6_scratches;
static int ipcomp6_scratch_users;
static LIST_HEAD(ipcomp6_tfms_list);

static int ipcomp6_input(struct xfrm_state *x, struct sk_buff *skb)
{
	int err = -ENOMEM;
	struct ipv6hdr *iph;
	struct ipv6_comp_hdr *ipch;
	int plen, dlen;
	struct ipcomp_data *ipcd = x->data;
	u8 *start, *scratch;
	struct crypto_tfm *tfm;
	int cpu;

	if (skb_linearize_cow(skb))
		goto out;

	skb->ip_summed = CHECKSUM_NONE;

	/* Remove ipcomp header and decompress original payload */
	iph = skb->nh.ipv6h;
	ipch = (void *)skb->data;
	skb->h.raw = skb->nh.raw + sizeof(*ipch);
	__skb_pull(skb, sizeof(*ipch));

	/* decompression */
	plen = skb->len;
	dlen = IPCOMP_SCRATCH_SIZE;
	start = skb->data;

	cpu = get_cpu();
	scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
	tfm = *per_cpu_ptr(ipcd->tfms, cpu);

	err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
	if (err) {
		err = -EINVAL;
		goto out_put_cpu;
	}

	if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) {
		err = -EINVAL;
		goto out_put_cpu;
	}

	err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
	if (err) {
		goto out_put_cpu;
	}

	skb_put(skb, dlen - plen);
	memcpy(skb->data, scratch, dlen);
	err = ipch->nexthdr;

out_put_cpu:
	put_cpu();
out:
	return err;
}

static int ipcomp6_output(struct xfrm_state *x, struct sk_buff *skb)
{
	int err;
	struct ipv6hdr *top_iph;
	int hdr_len;
	struct ipv6_comp_hdr *ipch;
	struct ipcomp_data *ipcd = x->data;
	int plen, dlen;
	u8 *start, *scratch;
	struct crypto_tfm *tfm;
	int cpu;

	hdr_len = skb->h.raw - skb->data;

	/* check whether datagram len is larger than threshold */
	if ((skb->len - hdr_len) < ipcd->threshold) {
		goto out_ok;
	}

	if (skb_linearize_cow(skb))
		goto out_ok;

	/* compression */
	plen = skb->len - hdr_len;
	dlen = IPCOMP_SCRATCH_SIZE;
	start = skb->h.raw;

	cpu = get_cpu();
	scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
	tfm = *per_cpu_ptr(ipcd->tfms, cpu);

	err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
	if (err || (dlen + sizeof(struct ipv6_comp_hdr)) >= plen) {
		put_cpu();
		goto out_ok;
	}
	memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
	put_cpu();
	pskb_trim(skb, hdr_len + dlen + sizeof(struct ip_comp_hdr));

	/* insert ipcomp header and replace datagram */
	top_iph = (struct ipv6hdr *)skb->data;

	top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));

	ipch = (struct ipv6_comp_hdr *)start;
	ipch->nexthdr = *skb->nh.raw;
	ipch->flags = 0;
	ipch->cpi = htons((u16 )ntohl(x->id.spi));
	*skb->nh.raw = IPPROTO_COMP;

out_ok:
	return 0;
}

static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
		                int type, int code, int offset, __u32 info)
{
	u32 spi;
	struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
	struct ipv6_comp_hdr *ipcomph = (struct ipv6_comp_hdr*)(skb->data+offset);
	struct xfrm_state *x;

	if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG)
		return;

	spi = htonl(ntohs(ipcomph->cpi));
	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);
	if (!x)
		return;

	printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIP6_FMT "\n",
			spi, NIP6(iph->daddr));
	xfrm_state_put(x);
}

static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
{
	struct xfrm_state *t = NULL;

	t = xfrm_state_alloc();
	if (!t)
		goto out;

	t->id.proto = IPPROTO_IPV6;
	t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
	if (!t->id.spi)
		goto error;

	memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
	memcpy(&t->sel, &x->sel, sizeof(t->sel));
	t->props.family = AF_INET6;
	t->props.mode = 1;
	memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));

	if (xfrm_init_state(t))
		goto error;

	atomic_set(&t->tunnel_users, 1);

out:
	return t;

error:
	t->km.state = XFRM_STATE_DEAD;
	xfrm_state_put(t);
	t = NULL;
	goto out;
}

static int ipcomp6_tunnel_attach(struct xfrm_state *x)
{
	int err = 0;
	struct xfrm_state *t = NULL;
	u32 spi;

	spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
	if (spi)
		t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr,
					      spi, IPPROTO_IPV6, AF_INET6);
	if (!t) {
		t = ipcomp6_tunnel_create(x);
		if (!t) {
			err = -EINVAL;
			goto out;
		}
		xfrm_state_insert(t);
		xfrm_state_hold(t);
	}
	x->tunnel = t;
	atomic_inc(&t->tunnel_users);

out:
	return err;
}

static void ipcomp6_free_scratches(void)
{
	int i;
	void **scratches;

	if (--ipcomp6_scratch_users)
		return;

	scratches = ipcomp6_scratches;
	if (!scratches)
		return;

	for_each_possible_cpu(i) {
		void *scratch = *per_cpu_ptr(scratches, i);

		vfree(scratch);
	}

	free_percpu(scratches);
}

static void **ipcomp6_alloc_scratches(void)
{
	int i;
	void **scratches;

	if (ipcomp6_scratch_users++)
		return ipcomp6_scratches;

	scratches = alloc_percpu(void *);
	if (!scratches)
		return NULL;

	ipcomp6_scratches = scratches;

	for_each_possible_cpu(i) {
		void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
		if (!scratch)
			return NULL;
		*per_cpu_ptr(scratches, i) = scratch;
	}

	return scratches;
}

static void ipcomp6_free_tfms(struct crypto_tfm **tfms)
{
	struct ipcomp6_tfms *pos;
	int cpu;

	list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
		if (pos->tfms == tfms)
			break;
	}

	BUG_TRAP(pos);

	if (--pos->users)
		return;

	list_del(&pos->list);
	kfree(pos);

	if (!tfms)
		return;

	for_each_possible_cpu(cpu) {
		struct crypto_tfm *tfm = *per_cpu_ptr(tfms, cpu);
		crypto_free_tfm(tfm);
	}
	free_percpu(tfms);
}

static struct crypto_tfm **ipcomp6_alloc_tfms(const char *alg_name)
{
	struct ipcomp6_tfms *pos;
	struct crypto_tfm **tfms;
	int cpu;

	/* This can be any valid CPU ID so we don't need locking. */
	cpu = raw_smp_processor_id();

	list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
		struct crypto_tfm *tfm;

		tfms = pos->tfms;
		tfm = *per_cpu_ptr(tfms, cpu);

		if (!strcmp(crypto_tfm_alg_name(tfm), alg_name)) {
			pos->users++;
			return tfms;
		}
	}

	pos = kmalloc(sizeof(*pos), GFP_KERNEL);
	if (!pos)
		return NULL;

	pos->users = 1;
	INIT_LIST_HEAD(&pos->list);
	list_add(&pos->list, &ipcomp6_tfms_list);

	pos->tfms = tfms = alloc_percpu(struct crypto_tfm *);
	if (!tfms)
		goto error;

	for_each_possible_cpu(cpu) {
		struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0);
		if (!tfm)
			goto error;
		*per_cpu_ptr(tfms, cpu) = tfm;
	}

	return tfms;

error:
	ipcomp6_free_tfms(tfms);
	return NULL;
}

static void ipcomp6_free_data(struct ipcomp_data *ipcd)
{
	if (ipcd->tfms)
		ipcomp6_free_tfms(ipcd->tfms);
	ipcomp6_free_scratches();
}

static void ipcomp6_destroy(struct xfrm_state *x)
{
	struct ipcomp_data *ipcd = x->data;
	if (!ipcd)
		return;
	xfrm_state_delete_tunnel(x);
	mutex_lock(&ipcomp6_resource_mutex);
	ipcomp6_free_data(ipcd);
	mutex_unlock(&ipcomp6_resource_mutex);
	kfree(ipcd);

	xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
}

static int ipcomp6_init_state(struct xfrm_state *x)
{
	int err;
	struct ipcomp_data *ipcd;
	struct xfrm_algo_desc *calg_desc;

	err = -EINVAL;
	if (!x->calg)
		goto out;

	if (x->encap)
		goto out;

	err = -ENOMEM;
	ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
	if (!ipcd)
		goto out;

	x->props.header_len = 0;
	if (x->props.mode)
		x->props.header_len += sizeof(struct ipv6hdr);
	
	mutex_lock(&ipcomp6_resource_mutex);
	if (!ipcomp6_alloc_scratches())
		goto error;

	ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name);
	if (!ipcd->tfms)
		goto error;
	mutex_unlock(&ipcomp6_resource_mutex);

	if (x->props.mode) {
		err = ipcomp6_tunnel_attach(x);
		if (err)
			goto error_tunnel;
	}

	calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
	BUG_ON(!calg_desc);
	ipcd->threshold = calg_desc->uinfo.comp.threshold;
	x->data = ipcd;
	err = 0;
out:
	return err;
error_tunnel:
	mutex_lock(&ipcomp6_resource_mutex);
error:
	ipcomp6_free_data(ipcd);
	mutex_unlock(&ipcomp6_resource_mutex);
	kfree(ipcd);

	goto out;
}

static struct xfrm_type ipcomp6_type = 
{
	.description	= "IPCOMP6",
	.owner		= THIS_MODULE,
	.proto		= IPPROTO_COMP,
	.init_state	= ipcomp6_init_state,
	.destructor	= ipcomp6_destroy,
	.input		= ipcomp6_input,
	.output		= ipcomp6_output,
};

static struct inet6_protocol ipcomp6_protocol = 
{
	.handler	= xfrm6_rcv,
	.err_handler	= ipcomp6_err,
	.flags		= INET6_PROTO_NOPOLICY,
};

static int __init ipcomp6_init(void)
{
	if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
		printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
		return -EAGAIN;
	}
	if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
		printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
		xfrm_unregister_type(&ipcomp6_type, AF_INET6);
		return -EAGAIN;
	}
	return 0;
}

static void __exit ipcomp6_fini(void)
{
	if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) 
		printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
	if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
		printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
}

module_init(ipcomp6_init);
module_exit(ipcomp6_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173
	3	*
	4	* Copyright (C)2003 USAGI/WIDE Project
	5	*
	6	* Author Mitsuru KANDA <mk@linux-ipv6.org>
	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 as published by
	10	* the Free Software Foundation; either version 2 of the License, or
	11	* (at your option) any later version.
	12	*
	13	* This program is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	* GNU General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU General Public License
	19	* along with this program; if not, write to the Free Software
	20	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	21	*/
	22	/*
	23	* [Memo]
	24	*
	25	* Outbound:
	26	* The compression of IP datagram MUST be done before AH/ESP processing,
	27	* fragmentation, and the addition of Hop-by-Hop/Routing header.
	28	*
	29	* Inbound:
	30	* The decompression of IP datagram MUST be done after the reassembly,
	31	* AH/ESP processing.
	32	*/
1da177e4 LT	33	#include <linux/module.h>
	34	#include <net/ip.h>
	35	#include <net/xfrm.h>
	36	#include <net/ipcomp.h>
	37	#include <asm/scatterlist.h>
	38	#include <asm/semaphore.h>
	39	#include <linux/crypto.h>
	40	#include <linux/pfkeyv2.h>
	41	#include <linux/random.h>
	42	#include <linux/percpu.h>
	43	#include <linux/smp.h>
	44	#include <linux/list.h>
	45	#include <linux/vmalloc.h>
	46	#include <linux/rtnetlink.h>
	47	#include <net/icmp.h>
	48	#include <net/ipv6.h>
14c85021	49	#include <net/protocol.h>
1da177e4 LT	50	#include <linux/ipv6.h>
1da177e4 LT	51	#include <linux/icmpv6.h>
4a3e2f71	52	#include <linux/mutex.h>
1da177e4 LT	53
	54	struct ipcomp6_tfms {
	55	struct list_head list;
	56	struct crypto_tfm **tfms;
	57	int users;
	58	};
	59
4a3e2f71	60	static DEFINE_MUTEX(ipcomp6_resource_mutex);
1da177e4 LT	61	static void **ipcomp6_scratches;
	62	static int ipcomp6_scratch_users;
	63	static LIST_HEAD(ipcomp6_tfms_list);
	64
e695633e	65	static int ipcomp6_input(struct xfrm_state x, struct sk_buff skb)
1da177e4	66	{
364c6bad	67	int err = -ENOMEM;
1da177e4	68	struct ipv6hdr *iph;
31a4ab93	69	struct ipv6_comp_hdr *ipch;
1da177e4 LT	70	int plen, dlen;
	71	struct ipcomp_data *ipcd = x->data;
	72	u8 start, scratch;
	73	struct crypto_tfm *tfm;
	74	int cpu;
	75
364c6bad	76	if (skb_linearize_cow(skb))
1da177e4	77	goto out;
1da177e4 LT	78
	79	skb->ip_summed = CHECKSUM_NONE;
	80
	81	/* Remove ipcomp header and decompress original payload */
	82	iph = skb->nh.ipv6h;
31a4ab93 HX	83	ipch = (void *)skb->data;
	84	skb->h.raw = skb->nh.raw + sizeof(*ipch);
	85	__skb_pull(skb, sizeof(*ipch));
1da177e4 LT	86
	87	/* decompression */
	88	plen = skb->len;
	89	dlen = IPCOMP_SCRATCH_SIZE;
	90	start = skb->data;
	91
	92	cpu = get_cpu();
	93	scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
	94	tfm = *per_cpu_ptr(ipcd->tfms, cpu);
	95
	96	err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
	97	if (err) {
	98	err = -EINVAL;
	99	goto out_put_cpu;
	100	}
	101
	102	if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) {
	103	err = -EINVAL;
	104	goto out_put_cpu;
	105	}
	106
	107	err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
	108	if (err) {
	109	goto out_put_cpu;
	110	}
	111
	112	skb_put(skb, dlen - plen);
	113	memcpy(skb->data, scratch, dlen);
31a4ab93	114	err = ipch->nexthdr;
1da177e4	115
1da177e4 LT	116	out_put_cpu:
	117	put_cpu();
	118	out:
1da177e4 LT	119	return err;
	120	}
	121
	122	static int ipcomp6_output(struct xfrm_state x, struct sk_buff skb)
	123	{
	124	int err;
	125	struct ipv6hdr *top_iph;
	126	int hdr_len;
	127	struct ipv6_comp_hdr *ipch;
	128	struct ipcomp_data *ipcd = x->data;
	129	int plen, dlen;
	130	u8 start, scratch;
	131	struct crypto_tfm *tfm;
	132	int cpu;
	133
	134	hdr_len = skb->h.raw - skb->data;
	135
	136	/* check whether datagram len is larger than threshold */
	137	if ((skb->len - hdr_len) < ipcd->threshold) {
	138	goto out_ok;
	139	}
	140
364c6bad	141	if (skb_linearize_cow(skb))
1da177e4	142	goto out_ok;
1da177e4 LT	143
	144	/* compression */
	145	plen = skb->len - hdr_len;
	146	dlen = IPCOMP_SCRATCH_SIZE;
	147	start = skb->h.raw;
	148
	149	cpu = get_cpu();
	150	scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
	151	tfm = *per_cpu_ptr(ipcd->tfms, cpu);
	152
	153	err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
	154	if (err \|\| (dlen + sizeof(struct ipv6_comp_hdr)) >= plen) {
	155	put_cpu();
	156	goto out_ok;
	157	}
	158	memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
	159	put_cpu();
	160	pskb_trim(skb, hdr_len + dlen + sizeof(struct ip_comp_hdr));
	161
	162	/* insert ipcomp header and replace datagram */
	163	top_iph = (struct ipv6hdr *)skb->data;
	164
	165	top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
	166
	167	ipch = (struct ipv6_comp_hdr *)start;
	168	ipch->nexthdr = *skb->nh.raw;
	169	ipch->flags = 0;
	170	ipch->cpi = htons((u16 )ntohl(x->id.spi));
	171	*skb->nh.raw = IPPROTO_COMP;
	172
	173	out_ok:
	174	return 0;
	175	}
	176
	177	static void ipcomp6_err(struct sk_buff skb, struct inet6_skb_parm opt,
	178	int type, int code, int offset, __u32 info)
	179	{
	180	u32 spi;
	181	struct ipv6hdr iph = (struct ipv6hdr)skb->data;
	182	struct ipv6_comp_hdr ipcomph = (struct ipv6_comp_hdr)(skb->data+offset);
	183	struct xfrm_state *x;
	184
	185	if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG)
	186	return;
	187
4195f814	188	spi = htonl(ntohs(ipcomph->cpi));
1da177e4 LT	189	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);
	190	if (!x)
	191	return;
	192
46b86a2d	193	printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIP6_FMT "\n",
1da177e4 LT	194	spi, NIP6(iph->daddr));
	195	xfrm_state_put(x);
	196	}
	197
	198	static struct xfrm_state ipcomp6_tunnel_create(struct xfrm_state x)
	199	{
	200	struct xfrm_state *t = NULL;
	201
	202	t = xfrm_state_alloc();
	203	if (!t)
	204	goto out;
	205
	206	t->id.proto = IPPROTO_IPV6;
	207	t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
6abaaaae HX	208	if (!t->id.spi)
	209	goto error;
	210
1da177e4 LT	211	memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
	212	memcpy(&t->sel, &x->sel, sizeof(t->sel));
	213	t->props.family = AF_INET6;
	214	t->props.mode = 1;
	215	memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
	216
72cb6962	217	if (xfrm_init_state(t))
1da177e4 LT	218	goto error;
1da177e4 LT	219
1da177e4 LT	220	atomic_set(&t->tunnel_users, 1);
	221
	222	out:
	223	return t;
	224
	225	error:
6abaaaae	226	t->km.state = XFRM_STATE_DEAD;
1da177e4	227	xfrm_state_put(t);
6abaaaae	228	t = NULL;
1da177e4 LT	229	goto out;
	230	}
	231
	232	static int ipcomp6_tunnel_attach(struct xfrm_state *x)
	233	{
	234	int err = 0;
	235	struct xfrm_state *t = NULL;
	236	u32 spi;
	237
	238	spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
	239	if (spi)
	240	t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr,
	241	spi, IPPROTO_IPV6, AF_INET6);
	242	if (!t) {
	243	t = ipcomp6_tunnel_create(x);
	244	if (!t) {
	245	err = -EINVAL;
	246	goto out;
	247	}
	248	xfrm_state_insert(t);
	249	xfrm_state_hold(t);
	250	}
	251	x->tunnel = t;
	252	atomic_inc(&t->tunnel_users);
	253
	254	out:
	255	return err;
	256	}
	257
	258	static void ipcomp6_free_scratches(void)
	259	{
	260	int i;
	261	void **scratches;
	262
	263	if (--ipcomp6_scratch_users)
	264	return;
	265
	266	scratches = ipcomp6_scratches;
	267	if (!scratches)
	268	return;
	269
6f912042	270	for_each_possible_cpu(i) {
1da177e4	271	void scratch = per_cpu_ptr(scratches, i);
2b191bef JJ	272
2b191bef JJ	273	vfree(scratch);
1da177e4 LT	274	}
	275
	276	free_percpu(scratches);
	277	}
	278
	279	static void **ipcomp6_alloc_scratches(void)
	280	{
	281	int i;
	282	void **scratches;
	283
	284	if (ipcomp6_scratch_users++)
	285	return ipcomp6_scratches;
	286
	287	scratches = alloc_percpu(void *);
	288	if (!scratches)
	289	return NULL;
	290
	291	ipcomp6_scratches = scratches;
	292
6f912042	293	for_each_possible_cpu(i) {
1da177e4 LT	294	void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
	295	if (!scratch)
	296	return NULL;
	297	*per_cpu_ptr(scratches, i) = scratch;
	298	}
	299
	300	return scratches;
	301	}
	302
	303	static void ipcomp6_free_tfms(struct crypto_tfm **tfms)
	304	{
	305	struct ipcomp6_tfms *pos;
	306	int cpu;
	307
	308	list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
	309	if (pos->tfms == tfms)
	310	break;
	311	}
	312
	313	BUG_TRAP(pos);
	314
	315	if (--pos->users)
	316	return;
	317
	318	list_del(&pos->list);
	319	kfree(pos);
	320
	321	if (!tfms)
	322	return;
	323
6f912042	324	for_each_possible_cpu(cpu) {
1da177e4	325	struct crypto_tfm tfm = per_cpu_ptr(tfms, cpu);
573dbd95	326	crypto_free_tfm(tfm);
1da177e4 LT	327	}
	328	free_percpu(tfms);
	329	}
	330
	331	static struct crypto_tfm *ipcomp6_alloc_tfms(const char alg_name)
	332	{
	333	struct ipcomp6_tfms *pos;
	334	struct crypto_tfm **tfms;
	335	int cpu;
	336
	337	/* This can be any valid CPU ID so we don't need locking. */
6fc8b9e7	338	cpu = raw_smp_processor_id();
1da177e4 LT	339
	340	list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
	341	struct crypto_tfm *tfm;
	342
	343	tfms = pos->tfms;
	344	tfm = *per_cpu_ptr(tfms, cpu);
	345
	346	if (!strcmp(crypto_tfm_alg_name(tfm), alg_name)) {
	347	pos->users++;
	348	return tfms;
	349	}
	350	}
	351
	352	pos = kmalloc(sizeof(*pos), GFP_KERNEL);
	353	if (!pos)
	354	return NULL;
	355
	356	pos->users = 1;
	357	INIT_LIST_HEAD(&pos->list);
	358	list_add(&pos->list, &ipcomp6_tfms_list);
	359
	360	pos->tfms = tfms = alloc_percpu(struct crypto_tfm *);
	361	if (!tfms)
	362	goto error;
	363
6f912042	364	for_each_possible_cpu(cpu) {
1da177e4 LT	365	struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0);
	366	if (!tfm)
	367	goto error;
	368	*per_cpu_ptr(tfms, cpu) = tfm;
	369	}
	370
	371	return tfms;
	372
	373	error:
	374	ipcomp6_free_tfms(tfms);
	375	return NULL;
	376	}
	377
	378	static void ipcomp6_free_data(struct ipcomp_data *ipcd)
	379	{
	380	if (ipcd->tfms)
	381	ipcomp6_free_tfms(ipcd->tfms);
	382	ipcomp6_free_scratches();
	383	}
	384
	385	static void ipcomp6_destroy(struct xfrm_state *x)
	386	{
	387	struct ipcomp_data *ipcd = x->data;
	388	if (!ipcd)
	389	return;
	390	xfrm_state_delete_tunnel(x);
4a3e2f71	391	mutex_lock(&ipcomp6_resource_mutex);
1da177e4	392	ipcomp6_free_data(ipcd);
4a3e2f71	393	mutex_unlock(&ipcomp6_resource_mutex);
1da177e4 LT	394	kfree(ipcd);
	395
	396	xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
	397	}
	398
72cb6962	399	static int ipcomp6_init_state(struct xfrm_state *x)
1da177e4 LT	400	{
	401	int err;
	402	struct ipcomp_data *ipcd;
	403	struct xfrm_algo_desc *calg_desc;
	404
	405	err = -EINVAL;
	406	if (!x->calg)
	407	goto out;
	408
	409	if (x->encap)
	410	goto out;
	411
	412	err = -ENOMEM;
0c600eda	413	ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
1da177e4 LT	414	if (!ipcd)
	415	goto out;
	416
1da177e4 LT	417	x->props.header_len = 0;
	418	if (x->props.mode)
	419	x->props.header_len += sizeof(struct ipv6hdr);
	420
4a3e2f71	421	mutex_lock(&ipcomp6_resource_mutex);
1da177e4 LT	422	if (!ipcomp6_alloc_scratches())
	423	goto error;
	424
	425	ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name);
	426	if (!ipcd->tfms)
	427	goto error;
4a3e2f71	428	mutex_unlock(&ipcomp6_resource_mutex);
1da177e4 LT	429
	430	if (x->props.mode) {
	431	err = ipcomp6_tunnel_attach(x);
	432	if (err)
	433	goto error_tunnel;
	434	}
	435
	436	calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
	437	BUG_ON(!calg_desc);
	438	ipcd->threshold = calg_desc->uinfo.comp.threshold;
	439	x->data = ipcd;
	440	err = 0;
	441	out:
	442	return err;
	443	error_tunnel:
4a3e2f71	444	mutex_lock(&ipcomp6_resource_mutex);
1da177e4 LT	445	error:
1da177e4 LT	446	ipcomp6_free_data(ipcd);
4a3e2f71	447	mutex_unlock(&ipcomp6_resource_mutex);
1da177e4 LT	448	kfree(ipcd);
	449
	450	goto out;
	451	}
	452
	453	static struct xfrm_type ipcomp6_type =
	454	{
	455	.description = "IPCOMP6",
	456	.owner = THIS_MODULE,
	457	.proto = IPPROTO_COMP,
	458	.init_state = ipcomp6_init_state,
	459	.destructor = ipcomp6_destroy,
	460	.input = ipcomp6_input,
	461	.output = ipcomp6_output,
	462	};
	463
	464	static struct inet6_protocol ipcomp6_protocol =
	465	{
	466	.handler = xfrm6_rcv,
	467	.err_handler = ipcomp6_err,
	468	.flags = INET6_PROTO_NOPOLICY,
	469	};
	470
	471	static int __init ipcomp6_init(void)
	472	{
	473	if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
	474	printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
	475	return -EAGAIN;
	476	}
	477	if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
	478	printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
	479	xfrm_unregister_type(&ipcomp6_type, AF_INET6);
	480	return -EAGAIN;
	481	}
	482	return 0;
	483	}
	484
	485	static void __exit ipcomp6_fini(void)
	486	{
	487	if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
	488	printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
	489	if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
	490	printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
	491	}
	492
	493	module_init(ipcomp6_init);
	494	module_exit(ipcomp6_fini);
	495	MODULE_LICENSE("GPL");
	496	MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
	497	MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
	498
	499