[net-next-2.6.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/config.h>
#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	*/
	33	#include <linux/config.h>
	34	#include <linux/module.h>
	35	#include <net/ip.h>
	36	#include <net/xfrm.h>
	37	#include <net/ipcomp.h>
	38	#include <asm/scatterlist.h>
	39	#include <asm/semaphore.h>
	40	#include <linux/crypto.h>
	41	#include <linux/pfkeyv2.h>
	42	#include <linux/random.h>
	43	#include <linux/percpu.h>
	44	#include <linux/smp.h>
	45	#include <linux/list.h>
	46	#include <linux/vmalloc.h>
	47	#include <linux/rtnetlink.h>
	48	#include <net/icmp.h>
	49	#include <net/ipv6.h>
14c85021	50	#include <net/protocol.h>
1da177e4 LT	51	#include <linux/ipv6.h>
1da177e4 LT	52	#include <linux/icmpv6.h>
4a3e2f71	53	#include <linux/mutex.h>
1da177e4 LT	54
	55	struct ipcomp6_tfms {
	56	struct list_head list;
	57	struct crypto_tfm **tfms;
	58	int users;
	59	};
	60
4a3e2f71	61	static DEFINE_MUTEX(ipcomp6_resource_mutex);
1da177e4 LT	62	static void **ipcomp6_scratches;
	63	static int ipcomp6_scratch_users;
	64	static LIST_HEAD(ipcomp6_tfms_list);
	65
e695633e	66	static int ipcomp6_input(struct xfrm_state x, struct sk_buff skb)
1da177e4	67	{
364c6bad	68	int err = -ENOMEM;
1da177e4	69	struct ipv6hdr *iph;
31a4ab93	70	struct ipv6_comp_hdr *ipch;
1da177e4 LT	71	int plen, dlen;
	72	struct ipcomp_data *ipcd = x->data;
	73	u8 start, scratch;
	74	struct crypto_tfm *tfm;
	75	int cpu;
	76
364c6bad	77	if (skb_linearize_cow(skb))
1da177e4	78	goto out;
1da177e4 LT	79
	80	skb->ip_summed = CHECKSUM_NONE;
	81
	82	/* Remove ipcomp header and decompress original payload */
	83	iph = skb->nh.ipv6h;
31a4ab93 HX	84	ipch = (void *)skb->data;
	85	skb->h.raw = skb->nh.raw + sizeof(*ipch);
	86	__skb_pull(skb, sizeof(*ipch));
1da177e4 LT	87
	88	/* decompression */
	89	plen = skb->len;
	90	dlen = IPCOMP_SCRATCH_SIZE;
	91	start = skb->data;
	92
	93	cpu = get_cpu();
	94	scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
	95	tfm = *per_cpu_ptr(ipcd->tfms, cpu);
	96
	97	err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
	98	if (err) {
	99	err = -EINVAL;
	100	goto out_put_cpu;
	101	}
	102
	103	if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) {
	104	err = -EINVAL;
	105	goto out_put_cpu;
	106	}
	107
	108	err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
	109	if (err) {
	110	goto out_put_cpu;
	111	}
	112
	113	skb_put(skb, dlen - plen);
	114	memcpy(skb->data, scratch, dlen);
31a4ab93	115	err = ipch->nexthdr;
1da177e4	116
1da177e4 LT	117	out_put_cpu:
	118	put_cpu();
	119	out:
1da177e4 LT	120	return err;
	121	}
	122
	123	static int ipcomp6_output(struct xfrm_state x, struct sk_buff skb)
	124	{
	125	int err;
	126	struct ipv6hdr *top_iph;
	127	int hdr_len;
	128	struct ipv6_comp_hdr *ipch;
	129	struct ipcomp_data *ipcd = x->data;
	130	int plen, dlen;
	131	u8 start, scratch;
	132	struct crypto_tfm *tfm;
	133	int cpu;
	134
	135	hdr_len = skb->h.raw - skb->data;
	136
	137	/* check whether datagram len is larger than threshold */
	138	if ((skb->len - hdr_len) < ipcd->threshold) {
	139	goto out_ok;
	140	}
	141
364c6bad	142	if (skb_linearize_cow(skb))
1da177e4	143	goto out_ok;
1da177e4 LT	144
	145	/* compression */
	146	plen = skb->len - hdr_len;
	147	dlen = IPCOMP_SCRATCH_SIZE;
	148	start = skb->h.raw;
	149
	150	cpu = get_cpu();
	151	scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
	152	tfm = *per_cpu_ptr(ipcd->tfms, cpu);
	153
	154	err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
	155	if (err \|\| (dlen + sizeof(struct ipv6_comp_hdr)) >= plen) {
	156	put_cpu();
	157	goto out_ok;
	158	}
	159	memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
	160	put_cpu();
	161	pskb_trim(skb, hdr_len + dlen + sizeof(struct ip_comp_hdr));
	162
	163	/* insert ipcomp header and replace datagram */
	164	top_iph = (struct ipv6hdr *)skb->data;
	165
	166	top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
	167
	168	ipch = (struct ipv6_comp_hdr *)start;
	169	ipch->nexthdr = *skb->nh.raw;
	170	ipch->flags = 0;
	171	ipch->cpi = htons((u16 )ntohl(x->id.spi));
	172	*skb->nh.raw = IPPROTO_COMP;
	173
	174	out_ok:
	175	return 0;
	176	}
	177
	178	static void ipcomp6_err(struct sk_buff skb, struct inet6_skb_parm opt,
	179	int type, int code, int offset, __u32 info)
	180	{
	181	u32 spi;
	182	struct ipv6hdr iph = (struct ipv6hdr)skb->data;
	183	struct ipv6_comp_hdr ipcomph = (struct ipv6_comp_hdr)(skb->data+offset);
	184	struct xfrm_state *x;
	185
	186	if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG)
	187	return;
	188
4195f814	189	spi = htonl(ntohs(ipcomph->cpi));
1da177e4 LT	190	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);
	191	if (!x)
	192	return;
	193
46b86a2d	194	printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIP6_FMT "\n",
1da177e4 LT	195	spi, NIP6(iph->daddr));
	196	xfrm_state_put(x);
	197	}
	198
	199	static struct xfrm_state ipcomp6_tunnel_create(struct xfrm_state x)
	200	{
	201	struct xfrm_state *t = NULL;
	202
	203	t = xfrm_state_alloc();
	204	if (!t)
	205	goto out;
	206
	207	t->id.proto = IPPROTO_IPV6;
	208	t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
6abaaaae HX	209	if (!t->id.spi)
	210	goto error;
	211
1da177e4 LT	212	memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
	213	memcpy(&t->sel, &x->sel, sizeof(t->sel));
	214	t->props.family = AF_INET6;
	215	t->props.mode = 1;
	216	memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
	217
72cb6962	218	if (xfrm_init_state(t))
1da177e4 LT	219	goto error;
1da177e4 LT	220
1da177e4 LT	221	atomic_set(&t->tunnel_users, 1);
	222
	223	out:
	224	return t;
	225
	226	error:
6abaaaae	227	t->km.state = XFRM_STATE_DEAD;
1da177e4	228	xfrm_state_put(t);
6abaaaae	229	t = NULL;
1da177e4 LT	230	goto out;
	231	}
	232
	233	static int ipcomp6_tunnel_attach(struct xfrm_state *x)
	234	{
	235	int err = 0;
	236	struct xfrm_state *t = NULL;
	237	u32 spi;
	238
	239	spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
	240	if (spi)
	241	t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr,
	242	spi, IPPROTO_IPV6, AF_INET6);
	243	if (!t) {
	244	t = ipcomp6_tunnel_create(x);
	245	if (!t) {
	246	err = -EINVAL;
	247	goto out;
	248	}
	249	xfrm_state_insert(t);
	250	xfrm_state_hold(t);
	251	}
	252	x->tunnel = t;
	253	atomic_inc(&t->tunnel_users);
	254
	255	out:
	256	return err;
	257	}
	258
	259	static void ipcomp6_free_scratches(void)
	260	{
	261	int i;
	262	void **scratches;
	263
	264	if (--ipcomp6_scratch_users)
	265	return;
	266
	267	scratches = ipcomp6_scratches;
	268	if (!scratches)
	269	return;
	270
6f912042	271	for_each_possible_cpu(i) {
1da177e4	272	void scratch = per_cpu_ptr(scratches, i);
2b191bef JJ	273
2b191bef JJ	274	vfree(scratch);
1da177e4 LT	275	}
	276
	277	free_percpu(scratches);
	278	}
	279
	280	static void **ipcomp6_alloc_scratches(void)
	281	{
	282	int i;
	283	void **scratches;
	284
	285	if (ipcomp6_scratch_users++)
	286	return ipcomp6_scratches;
	287
	288	scratches = alloc_percpu(void *);
	289	if (!scratches)
	290	return NULL;
	291
	292	ipcomp6_scratches = scratches;
	293
6f912042	294	for_each_possible_cpu(i) {
1da177e4 LT	295	void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
	296	if (!scratch)
	297	return NULL;
	298	*per_cpu_ptr(scratches, i) = scratch;
	299	}
	300
	301	return scratches;
	302	}
	303
	304	static void ipcomp6_free_tfms(struct crypto_tfm **tfms)
	305	{
	306	struct ipcomp6_tfms *pos;
	307	int cpu;
	308
	309	list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
	310	if (pos->tfms == tfms)
	311	break;
	312	}
	313
	314	BUG_TRAP(pos);
	315
	316	if (--pos->users)
	317	return;
	318
	319	list_del(&pos->list);
	320	kfree(pos);
	321
	322	if (!tfms)
	323	return;
	324
6f912042	325	for_each_possible_cpu(cpu) {
1da177e4	326	struct crypto_tfm tfm = per_cpu_ptr(tfms, cpu);
573dbd95	327	crypto_free_tfm(tfm);
1da177e4 LT	328	}
	329	free_percpu(tfms);
	330	}
	331
	332	static struct crypto_tfm *ipcomp6_alloc_tfms(const char alg_name)
	333	{
	334	struct ipcomp6_tfms *pos;
	335	struct crypto_tfm **tfms;
	336	int cpu;
	337
	338	/* This can be any valid CPU ID so we don't need locking. */
6fc8b9e7	339	cpu = raw_smp_processor_id();
1da177e4 LT	340
	341	list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
	342	struct crypto_tfm *tfm;
	343
	344	tfms = pos->tfms;
	345	tfm = *per_cpu_ptr(tfms, cpu);
	346
	347	if (!strcmp(crypto_tfm_alg_name(tfm), alg_name)) {
	348	pos->users++;
	349	return tfms;
	350	}
	351	}
	352
	353	pos = kmalloc(sizeof(*pos), GFP_KERNEL);
	354	if (!pos)
	355	return NULL;
	356
	357	pos->users = 1;
	358	INIT_LIST_HEAD(&pos->list);
	359	list_add(&pos->list, &ipcomp6_tfms_list);
	360
	361	pos->tfms = tfms = alloc_percpu(struct crypto_tfm *);
	362	if (!tfms)
	363	goto error;
	364
6f912042	365	for_each_possible_cpu(cpu) {
1da177e4 LT	366	struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0);
	367	if (!tfm)
	368	goto error;
	369	*per_cpu_ptr(tfms, cpu) = tfm;
	370	}
	371
	372	return tfms;
	373
	374	error:
	375	ipcomp6_free_tfms(tfms);
	376	return NULL;
	377	}
	378
	379	static void ipcomp6_free_data(struct ipcomp_data *ipcd)
	380	{
	381	if (ipcd->tfms)
	382	ipcomp6_free_tfms(ipcd->tfms);
	383	ipcomp6_free_scratches();
	384	}
	385
	386	static void ipcomp6_destroy(struct xfrm_state *x)
	387	{
	388	struct ipcomp_data *ipcd = x->data;
	389	if (!ipcd)
	390	return;
	391	xfrm_state_delete_tunnel(x);
4a3e2f71	392	mutex_lock(&ipcomp6_resource_mutex);
1da177e4	393	ipcomp6_free_data(ipcd);
4a3e2f71	394	mutex_unlock(&ipcomp6_resource_mutex);
1da177e4 LT	395	kfree(ipcd);
	396
	397	xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
	398	}
	399
72cb6962	400	static int ipcomp6_init_state(struct xfrm_state *x)
1da177e4 LT	401	{
	402	int err;
	403	struct ipcomp_data *ipcd;
	404	struct xfrm_algo_desc *calg_desc;
	405
	406	err = -EINVAL;
	407	if (!x->calg)
	408	goto out;
	409
	410	if (x->encap)
	411	goto out;
	412
	413	err = -ENOMEM;
0c600eda	414	ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
1da177e4 LT	415	if (!ipcd)
	416	goto out;
	417
1da177e4 LT	418	x->props.header_len = 0;
	419	if (x->props.mode)
	420	x->props.header_len += sizeof(struct ipv6hdr);
	421
4a3e2f71	422	mutex_lock(&ipcomp6_resource_mutex);
1da177e4 LT	423	if (!ipcomp6_alloc_scratches())
	424	goto error;
	425
	426	ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name);
	427	if (!ipcd->tfms)
	428	goto error;
4a3e2f71	429	mutex_unlock(&ipcomp6_resource_mutex);
1da177e4 LT	430
	431	if (x->props.mode) {
	432	err = ipcomp6_tunnel_attach(x);
	433	if (err)
	434	goto error_tunnel;
	435	}
	436
	437	calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
	438	BUG_ON(!calg_desc);
	439	ipcd->threshold = calg_desc->uinfo.comp.threshold;
	440	x->data = ipcd;
	441	err = 0;
	442	out:
	443	return err;
	444	error_tunnel:
4a3e2f71	445	mutex_lock(&ipcomp6_resource_mutex);
1da177e4 LT	446	error:
1da177e4 LT	447	ipcomp6_free_data(ipcd);
4a3e2f71	448	mutex_unlock(&ipcomp6_resource_mutex);
1da177e4 LT	449	kfree(ipcd);
	450
	451	goto out;
	452	}
	453
	454	static struct xfrm_type ipcomp6_type =
	455	{
	456	.description = "IPCOMP6",
	457	.owner = THIS_MODULE,
	458	.proto = IPPROTO_COMP,
	459	.init_state = ipcomp6_init_state,
	460	.destructor = ipcomp6_destroy,
	461	.input = ipcomp6_input,
	462	.output = ipcomp6_output,
	463	};
	464
	465	static struct inet6_protocol ipcomp6_protocol =
	466	{
	467	.handler = xfrm6_rcv,
	468	.err_handler = ipcomp6_err,
	469	.flags = INET6_PROTO_NOPOLICY,
	470	};
	471
	472	static int __init ipcomp6_init(void)
	473	{
	474	if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
	475	printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
	476	return -EAGAIN;
	477	}
	478	if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
	479	printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
	480	xfrm_unregister_type(&ipcomp6_type, AF_INET6);
	481	return -EAGAIN;
	482	}
	483	return 0;
	484	}
	485
	486	static void __exit ipcomp6_fini(void)
	487	{
	488	if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
	489	printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
	490	if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
	491	printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
	492	}
	493
	494	module_init(ipcomp6_init);
	495	module_exit(ipcomp6_fini);
	496	MODULE_LICENSE("GPL");
	497	MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
	498	MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
	499
	500