[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/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 = 0;
	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_is_nonlinear(skb) || skb_cloned(skb)) &&
		skb_linearize(skb, GFP_ATOMIC) != 0) {
		err = -ENOMEM;
		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_is_nonlinear(skb) || skb_cloned(skb)) &&
		skb_linearize(skb, GFP_ATOMIC) != 0) {
		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 LT	67	{
1da177e4 LT	68	int err = 0;
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
	77	if ((skb_is_nonlinear(skb) \|\| skb_cloned(skb)) &&
	78	skb_linearize(skb, GFP_ATOMIC) != 0) {
	79	err = -ENOMEM;
	80	goto out;
	81	}
	82
	83	skb->ip_summed = CHECKSUM_NONE;
	84
	85	/* Remove ipcomp header and decompress original payload */
	86	iph = skb->nh.ipv6h;
31a4ab93 HX	87	ipch = (void *)skb->data;
	88	skb->h.raw = skb->nh.raw + sizeof(*ipch);
	89	__skb_pull(skb, sizeof(*ipch));
1da177e4 LT	90
	91	/* decompression */
	92	plen = skb->len;
	93	dlen = IPCOMP_SCRATCH_SIZE;
	94	start = skb->data;
	95
	96	cpu = get_cpu();
	97	scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
	98	tfm = *per_cpu_ptr(ipcd->tfms, cpu);
	99
	100	err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
	101	if (err) {
	102	err = -EINVAL;
	103	goto out_put_cpu;
	104	}
	105
	106	if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) {
	107	err = -EINVAL;
	108	goto out_put_cpu;
	109	}
	110
	111	err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
	112	if (err) {
	113	goto out_put_cpu;
	114	}
	115
	116	skb_put(skb, dlen - plen);
	117	memcpy(skb->data, scratch, dlen);
31a4ab93	118	err = ipch->nexthdr;
1da177e4	119
1da177e4 LT	120	out_put_cpu:
	121	put_cpu();
	122	out:
1da177e4 LT	123	return err;
	124	}
	125
	126	static int ipcomp6_output(struct xfrm_state x, struct sk_buff skb)
	127	{
	128	int err;
	129	struct ipv6hdr *top_iph;
	130	int hdr_len;
	131	struct ipv6_comp_hdr *ipch;
	132	struct ipcomp_data *ipcd = x->data;
	133	int plen, dlen;
	134	u8 start, scratch;
	135	struct crypto_tfm *tfm;
	136	int cpu;
	137
	138	hdr_len = skb->h.raw - skb->data;
	139
	140	/* check whether datagram len is larger than threshold */
	141	if ((skb->len - hdr_len) < ipcd->threshold) {
	142	goto out_ok;
	143	}
	144
	145	if ((skb_is_nonlinear(skb) \|\| skb_cloned(skb)) &&
	146	skb_linearize(skb, GFP_ATOMIC) != 0) {
	147	goto out_ok;
	148	}
	149
	150	/* compression */
	151	plen = skb->len - hdr_len;
	152	dlen = IPCOMP_SCRATCH_SIZE;
	153	start = skb->h.raw;
	154
	155	cpu = get_cpu();
	156	scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
	157	tfm = *per_cpu_ptr(ipcd->tfms, cpu);
	158
	159	err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
	160	if (err \|\| (dlen + sizeof(struct ipv6_comp_hdr)) >= plen) {
	161	put_cpu();
	162	goto out_ok;
	163	}
	164	memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
	165	put_cpu();
	166	pskb_trim(skb, hdr_len + dlen + sizeof(struct ip_comp_hdr));
	167
	168	/* insert ipcomp header and replace datagram */
	169	top_iph = (struct ipv6hdr *)skb->data;
	170
	171	top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
	172
	173	ipch = (struct ipv6_comp_hdr *)start;
	174	ipch->nexthdr = *skb->nh.raw;
	175	ipch->flags = 0;
	176	ipch->cpi = htons((u16 )ntohl(x->id.spi));
	177	*skb->nh.raw = IPPROTO_COMP;
	178
	179	out_ok:
	180	return 0;
	181	}
	182
	183	static void ipcomp6_err(struct sk_buff skb, struct inet6_skb_parm opt,
	184	int type, int code, int offset, __u32 info)
	185	{
	186	u32 spi;
187	struct ipv6hdr iph = (struct ipv6hdr)skb->data;
188	struct ipv6_comp_hdr ipcomph = (struct ipv6_comp_hdr)(skb->data+offset);
189	struct xfrm_state *x;
190
191	if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG)
192	return;
193
4195f814	194	spi = htonl(ntohs(ipcomph->cpi));
1da177e4 LT	195	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);
	196	if (!x)
	197	return;
	198
46b86a2d	199	printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIP6_FMT "\n",
1da177e4 LT	200	spi, NIP6(iph->daddr));
	201	xfrm_state_put(x);
	202	}
	203
	204	static struct xfrm_state ipcomp6_tunnel_create(struct xfrm_state x)
	205	{
	206	struct xfrm_state *t = NULL;
	207
	208	t = xfrm_state_alloc();
	209	if (!t)
	210	goto out;
	211
	212	t->id.proto = IPPROTO_IPV6;
	213	t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
6abaaaae HX	214	if (!t->id.spi)
	215	goto error;
	216
1da177e4 LT	217	memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
	218	memcpy(&t->sel, &x->sel, sizeof(t->sel));
	219	t->props.family = AF_INET6;
	220	t->props.mode = 1;
	221	memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
	222
72cb6962	223	if (xfrm_init_state(t))
1da177e4 LT	224	goto error;
1da177e4 LT	225
1da177e4 LT	226	atomic_set(&t->tunnel_users, 1);
	227
	228	out:
	229	return t;
	230
	231	error:
6abaaaae	232	t->km.state = XFRM_STATE_DEAD;
1da177e4	233	xfrm_state_put(t);
6abaaaae	234	t = NULL;
1da177e4 LT	235	goto out;
	236	}
	237
	238	static int ipcomp6_tunnel_attach(struct xfrm_state *x)
	239	{
	240	int err = 0;
	241	struct xfrm_state *t = NULL;
	242	u32 spi;
	243
	244	spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
	245	if (spi)
	246	t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr,
	247	spi, IPPROTO_IPV6, AF_INET6);
	248	if (!t) {
	249	t = ipcomp6_tunnel_create(x);
	250	if (!t) {
	251	err = -EINVAL;
	252	goto out;
	253	}
	254	xfrm_state_insert(t);
	255	xfrm_state_hold(t);
	256	}
	257	x->tunnel = t;
	258	atomic_inc(&t->tunnel_users);
	259
	260	out:
	261	return err;
	262	}
	263
	264	static void ipcomp6_free_scratches(void)
	265	{
	266	int i;
	267	void **scratches;
	268
	269	if (--ipcomp6_scratch_users)
	270	return;
	271
	272	scratches = ipcomp6_scratches;
	273	if (!scratches)
	274	return;
	275
6f912042	276	for_each_possible_cpu(i) {
1da177e4	277	void scratch = per_cpu_ptr(scratches, i);
2b191bef JJ	278
2b191bef JJ	279	vfree(scratch);
1da177e4 LT	280	}
	281
	282	free_percpu(scratches);
	283	}
	284
	285	static void **ipcomp6_alloc_scratches(void)
	286	{
	287	int i;
	288	void **scratches;
	289
	290	if (ipcomp6_scratch_users++)
	291	return ipcomp6_scratches;
	292
	293	scratches = alloc_percpu(void *);
	294	if (!scratches)
	295	return NULL;
	296
	297	ipcomp6_scratches = scratches;
	298
6f912042	299	for_each_possible_cpu(i) {
1da177e4 LT	300	void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
	301	if (!scratch)
	302	return NULL;
	303	*per_cpu_ptr(scratches, i) = scratch;
	304	}
	305
	306	return scratches;
	307	}
	308
	309	static void ipcomp6_free_tfms(struct crypto_tfm **tfms)
	310	{
	311	struct ipcomp6_tfms *pos;
	312	int cpu;
	313
	314	list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
	315	if (pos->tfms == tfms)
	316	break;
	317	}
	318
	319	BUG_TRAP(pos);
	320
	321	if (--pos->users)
	322	return;
	323
	324	list_del(&pos->list);
	325	kfree(pos);
	326
	327	if (!tfms)
	328	return;
	329
6f912042	330	for_each_possible_cpu(cpu) {
1da177e4	331	struct crypto_tfm tfm = per_cpu_ptr(tfms, cpu);
573dbd95	332	crypto_free_tfm(tfm);
1da177e4 LT	333	}
	334	free_percpu(tfms);
	335	}
	336
	337	static struct crypto_tfm *ipcomp6_alloc_tfms(const char alg_name)
	338	{
	339	struct ipcomp6_tfms *pos;
	340	struct crypto_tfm **tfms;
	341	int cpu;
	342
	343	/* This can be any valid CPU ID so we don't need locking. */
6fc8b9e7	344	cpu = raw_smp_processor_id();
1da177e4 LT	345
	346	list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
	347	struct crypto_tfm *tfm;
	348
	349	tfms = pos->tfms;
	350	tfm = *per_cpu_ptr(tfms, cpu);
	351
	352	if (!strcmp(crypto_tfm_alg_name(tfm), alg_name)) {
	353	pos->users++;
	354	return tfms;
	355	}
	356	}
	357
	358	pos = kmalloc(sizeof(*pos), GFP_KERNEL);
	359	if (!pos)
	360	return NULL;
	361
	362	pos->users = 1;
	363	INIT_LIST_HEAD(&pos->list);
	364	list_add(&pos->list, &ipcomp6_tfms_list);
	365
	366	pos->tfms = tfms = alloc_percpu(struct crypto_tfm *);
	367	if (!tfms)
	368	goto error;
	369
6f912042	370	for_each_possible_cpu(cpu) {
1da177e4 LT	371	struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0);
	372	if (!tfm)
	373	goto error;
	374	*per_cpu_ptr(tfms, cpu) = tfm;
	375	}
	376
	377	return tfms;
	378
	379	error:
	380	ipcomp6_free_tfms(tfms);
	381	return NULL;
	382	}
	383
	384	static void ipcomp6_free_data(struct ipcomp_data *ipcd)
	385	{
	386	if (ipcd->tfms)
	387	ipcomp6_free_tfms(ipcd->tfms);
	388	ipcomp6_free_scratches();
	389	}
	390
	391	static void ipcomp6_destroy(struct xfrm_state *x)
	392	{
	393	struct ipcomp_data *ipcd = x->data;
	394	if (!ipcd)
	395	return;
	396	xfrm_state_delete_tunnel(x);
4a3e2f71	397	mutex_lock(&ipcomp6_resource_mutex);
1da177e4	398	ipcomp6_free_data(ipcd);
4a3e2f71	399	mutex_unlock(&ipcomp6_resource_mutex);
1da177e4 LT	400	kfree(ipcd);
	401
	402	xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
	403	}
	404
72cb6962	405	static int ipcomp6_init_state(struct xfrm_state *x)
1da177e4 LT	406	{
	407	int err;
	408	struct ipcomp_data *ipcd;
	409	struct xfrm_algo_desc *calg_desc;
	410
	411	err = -EINVAL;
	412	if (!x->calg)
	413	goto out;
	414
	415	if (x->encap)
	416	goto out;
	417
	418	err = -ENOMEM;
0c600eda	419	ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
1da177e4 LT	420	if (!ipcd)
	421	goto out;
	422
1da177e4 LT	423	x->props.header_len = 0;
	424	if (x->props.mode)
	425	x->props.header_len += sizeof(struct ipv6hdr);
	426
4a3e2f71	427	mutex_lock(&ipcomp6_resource_mutex);
1da177e4 LT	428	if (!ipcomp6_alloc_scratches())
	429	goto error;
	430
	431	ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name);
	432	if (!ipcd->tfms)
	433	goto error;
4a3e2f71	434	mutex_unlock(&ipcomp6_resource_mutex);
1da177e4 LT	435
	436	if (x->props.mode) {
	437	err = ipcomp6_tunnel_attach(x);
	438	if (err)
	439	goto error_tunnel;
	440	}
	441
	442	calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
	443	BUG_ON(!calg_desc);
	444	ipcd->threshold = calg_desc->uinfo.comp.threshold;
	445	x->data = ipcd;
	446	err = 0;
	447	out:
	448	return err;
	449	error_tunnel:
4a3e2f71	450	mutex_lock(&ipcomp6_resource_mutex);
1da177e4 LT	451	error:
1da177e4 LT	452	ipcomp6_free_data(ipcd);
4a3e2f71	453	mutex_unlock(&ipcomp6_resource_mutex);
1da177e4 LT	454	kfree(ipcd);
	455
	456	goto out;
	457	}
	458
	459	static struct xfrm_type ipcomp6_type =
	460	{
	461	.description = "IPCOMP6",
	462	.owner = THIS_MODULE,
	463	.proto = IPPROTO_COMP,
	464	.init_state = ipcomp6_init_state,
	465	.destructor = ipcomp6_destroy,
	466	.input = ipcomp6_input,
	467	.output = ipcomp6_output,
	468	};
	469
	470	static struct inet6_protocol ipcomp6_protocol =
	471	{
	472	.handler = xfrm6_rcv,
	473	.err_handler = ipcomp6_err,
	474	.flags = INET6_PROTO_NOPOLICY,
	475	};
	476
	477	static int __init ipcomp6_init(void)
	478	{
	479	if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
	480	printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
	481	return -EAGAIN;
	482	}
	483	if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
	484	printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
	485	xfrm_unregister_type(&ipcomp6_type, AF_INET6);
	486	return -EAGAIN;
	487	}
	488	return 0;
	489	}
	490
	491	static void __exit ipcomp6_fini(void)
	492	{
	493	if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
	494	printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
	495	if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
	496	printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
	497	}
	498
	499	module_init(ipcomp6_init);
	500	module_exit(ipcomp6_fini);
	501	MODULE_LICENSE("GPL");
	502	MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
	503	MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
	504
	505