[linux.git] / net / ipv4 / ipcomp.c

/*
 * IP Payload Compression Protocol (IPComp) - RFC3173.
 *
 * Copyright (c) 2003 James Morris <[email protected]>
 *
 * 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.
 *
 * Todo:
 *   - Tunable compression parameters.
 *   - Compression stats.
 *   - Adaptive compression.
 */
#include <linux/module.h>
#include <asm/scatterlist.h>
#include <asm/semaphore.h>
#include <linux/crypto.h>
#include <linux/pfkeyv2.h>
#include <linux/percpu.h>
#include <linux/smp.h>
#include <linux/list.h>
#include <linux/vmalloc.h>
#include <linux/rtnetlink.h>
#include <linux/mutex.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/icmp.h>
#include <net/ipcomp.h>
#include <net/protocol.h>

struct ipcomp_tfms {
	struct list_head list;
	struct crypto_comp **tfms;
	int users;
};

static DEFINE_MUTEX(ipcomp_resource_mutex);
static void **ipcomp_scratches;
static int ipcomp_scratch_users;
static LIST_HEAD(ipcomp_tfms_list);

static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb)
{
	int err, plen, dlen;
	struct ipcomp_data *ipcd = x->data;
	u8 *start, *scratch;
	struct crypto_comp *tfm;
	int cpu;
	
	plen = skb->len;
	dlen = IPCOMP_SCRATCH_SIZE;
	start = skb->data;

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

	err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
	if (err)
		goto out;

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

	err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
	if (err)
		goto out;
		
	skb->truesize += dlen - plen;
	__skb_put(skb, dlen - plen);
	memcpy(skb->data, scratch, dlen);
out:	
	put_cpu();
	return err;
}

static int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb)
{
	int err = -ENOMEM;
	struct iphdr *iph;
	struct ip_comp_hdr *ipch;

	if (skb_linearize_cow(skb))
	    	goto out;

	skb->ip_summed = CHECKSUM_NONE;

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

out:	
	return err;
}

static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb)
{
	int err, plen, dlen, ihlen;
	struct iphdr *iph = skb->nh.iph;
	struct ipcomp_data *ipcd = x->data;
	u8 *start, *scratch;
	struct crypto_comp *tfm;
	int cpu;
	
	ihlen = iph->ihl * 4;
	plen = skb->len - ihlen;
	dlen = IPCOMP_SCRATCH_SIZE;
	start = skb->data + ihlen;

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

	err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
	if (err)
		goto out;

	if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) {
		err = -EMSGSIZE;
		goto out;
	}
	
	memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
	put_cpu();

	pskb_trim(skb, ihlen + dlen + sizeof(struct ip_comp_hdr));
	return 0;
	
out:	
	put_cpu();
	return err;
}

static int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb)
{
	int err;
	struct iphdr *iph;
	struct ip_comp_hdr *ipch;
	struct ipcomp_data *ipcd = x->data;
	int hdr_len = 0;

	iph = skb->nh.iph;
	iph->tot_len = htons(skb->len);
	hdr_len = iph->ihl * 4;
	if ((skb->len - hdr_len) < ipcd->threshold) {
		/* Don't bother compressing */
		goto out_ok;
	}

	if (skb_linearize_cow(skb))
		goto out_ok;
	
	err = ipcomp_compress(x, skb);
	iph = skb->nh.iph;

	if (err) {
		goto out_ok;
	}

	/* Install ipcomp header, convert into ipcomp datagram. */
	iph->tot_len = htons(skb->len);
	ipch = (struct ip_comp_hdr *)((char *)iph + iph->ihl * 4);
	ipch->nexthdr = iph->protocol;
	ipch->flags = 0;
	ipch->cpi = htons((u16 )ntohl(x->id.spi));
	iph->protocol = IPPROTO_COMP;
	ip_send_check(iph);
	return 0;

out_ok:
	if (x->props.mode == XFRM_MODE_TUNNEL)
		ip_send_check(iph);
	return 0;
}

static void ipcomp4_err(struct sk_buff *skb, u32 info)
{
	u32 spi;
	struct iphdr *iph = (struct iphdr *)skb->data;
	struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
	struct xfrm_state *x;

	if (skb->h.icmph->type != ICMP_DEST_UNREACH ||
	    skb->h.icmph->code != ICMP_FRAG_NEEDED)
		return;

	spi = htonl(ntohs(ipch->cpi));
	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr,
	                      spi, IPPROTO_COMP, AF_INET);
	if (!x)
		return;
	NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%u.%u.%u.%u\n",
		 spi, NIPQUAD(iph->daddr));
	xfrm_state_put(x);
}

/* We always hold one tunnel user reference to indicate a tunnel */ 
static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
{
	struct xfrm_state *t;
	
	t = xfrm_state_alloc();
	if (t == NULL)
		goto out;

	t->id.proto = IPPROTO_IPIP;
	t->id.spi = x->props.saddr.a4;
	t->id.daddr.a4 = x->id.daddr.a4;
	memcpy(&t->sel, &x->sel, sizeof(t->sel));
	t->props.family = AF_INET;
	t->props.mode = XFRM_MODE_TUNNEL;
	t->props.saddr.a4 = x->props.saddr.a4;
	t->props.flags = x->props.flags;

	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;
}

/*
 * Must be protected by xfrm_cfg_mutex.  State and tunnel user references are
 * always incremented on success.
 */
static int ipcomp_tunnel_attach(struct xfrm_state *x)
{
	int err = 0;
	struct xfrm_state *t;

	t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr.a4,
	                      x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
	if (!t) {
		t = ipcomp_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 ipcomp_free_scratches(void)
{
	int i;
	void **scratches;

	if (--ipcomp_scratch_users)
		return;

	scratches = ipcomp_scratches;
	if (!scratches)
		return;

	for_each_possible_cpu(i)
		vfree(*per_cpu_ptr(scratches, i));

	free_percpu(scratches);
}

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

	if (ipcomp_scratch_users++)
		return ipcomp_scratches;

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

	ipcomp_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 ipcomp_free_tfms(struct crypto_comp **tfms)
{
	struct ipcomp_tfms *pos;
	int cpu;

	list_for_each_entry(pos, &ipcomp_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_comp *tfm = *per_cpu_ptr(tfms, cpu);
		crypto_free_comp(tfm);
	}
	free_percpu(tfms);
}

static struct crypto_comp **ipcomp_alloc_tfms(const char *alg_name)
{
	struct ipcomp_tfms *pos;
	struct crypto_comp **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, &ipcomp_tfms_list, list) {
		struct crypto_comp *tfm;

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

		if (!strcmp(crypto_comp_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, &ipcomp_tfms_list);

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

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

	return tfms;

error:
	ipcomp_free_tfms(tfms);
	return NULL;
}

static void ipcomp_free_data(struct ipcomp_data *ipcd)
{
	if (ipcd->tfms)
		ipcomp_free_tfms(ipcd->tfms);
	ipcomp_free_scratches();
}

static void ipcomp_destroy(struct xfrm_state *x)
{
	struct ipcomp_data *ipcd = x->data;
	if (!ipcd)
		return;
	xfrm_state_delete_tunnel(x);
	mutex_lock(&ipcomp_resource_mutex);
	ipcomp_free_data(ipcd);
	mutex_unlock(&ipcomp_resource_mutex);
	kfree(ipcd);
}

static int ipcomp_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 == XFRM_MODE_TUNNEL)
		x->props.header_len += sizeof(struct iphdr);

	mutex_lock(&ipcomp_resource_mutex);
	if (!ipcomp_alloc_scratches())
		goto error;

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

	if (x->props.mode == XFRM_MODE_TUNNEL) {
		err = ipcomp_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(&ipcomp_resource_mutex);
error:
	ipcomp_free_data(ipcd);
	mutex_unlock(&ipcomp_resource_mutex);
	kfree(ipcd);
	goto out;
}

static struct xfrm_type ipcomp_type = {
	.description	= "IPCOMP4",
	.owner		= THIS_MODULE,
	.proto	     	= IPPROTO_COMP,
	.init_state	= ipcomp_init_state,
	.destructor	= ipcomp_destroy,
	.input		= ipcomp_input,
	.output		= ipcomp_output
};

static struct net_protocol ipcomp4_protocol = {
	.handler	=	xfrm4_rcv,
	.err_handler	=	ipcomp4_err,
	.no_policy	=	1,
};

static int __init ipcomp4_init(void)
{
	if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
		printk(KERN_INFO "ipcomp init: can't add xfrm type\n");
		return -EAGAIN;
	}
	if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
		printk(KERN_INFO "ipcomp init: can't add protocol\n");
		xfrm_unregister_type(&ipcomp_type, AF_INET);
		return -EAGAIN;
	}
	return 0;
}

static void __exit ipcomp4_fini(void)
{
	if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
		printk(KERN_INFO "ip ipcomp close: can't remove protocol\n");
	if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
		printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n");
}

module_init(ipcomp4_init);
module_exit(ipcomp4_fini);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173");
MODULE_AUTHOR("James Morris <[email protected]>");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* IP Payload Compression Protocol (IPComp) - RFC3173.
	3	*
	4	* Copyright (c) 2003 James Morris <[email protected]>
	5	*
	6	* This program is free software; you can redistribute it and/or modify it
	7	* under the terms of the GNU General Public License as published by the Free
	8	* Software Foundation; either version 2 of the License, or (at your option)
	9	* any later version.
	10	*
	11	* Todo:
	12	* - Tunable compression parameters.
	13	* - Compression stats.
	14	* - Adaptive compression.
	15	*/
1da177e4 LT	16	#include <linux/module.h>
	17	#include <asm/scatterlist.h>
	18	#include <asm/semaphore.h>
	19	#include <linux/crypto.h>
	20	#include <linux/pfkeyv2.h>
	21	#include <linux/percpu.h>
	22	#include <linux/smp.h>
	23	#include <linux/list.h>
	24	#include <linux/vmalloc.h>
	25	#include <linux/rtnetlink.h>
4a3e2f71	26	#include <linux/mutex.h>
1da177e4 LT	27	#include <net/ip.h>
	28	#include <net/xfrm.h>
	29	#include <net/icmp.h>
	30	#include <net/ipcomp.h>
14c85021	31	#include <net/protocol.h>
1da177e4 LT	32
	33	struct ipcomp_tfms {
	34	struct list_head list;
e4d5b79c	35	struct crypto_comp **tfms;
1da177e4 LT	36	int users;
	37	};
	38
4a3e2f71	39	static DEFINE_MUTEX(ipcomp_resource_mutex);
1da177e4 LT	40	static void **ipcomp_scratches;
	41	static int ipcomp_scratch_users;
	42	static LIST_HEAD(ipcomp_tfms_list);
	43
	44	static int ipcomp_decompress(struct xfrm_state x, struct sk_buff skb)
	45	{
	46	int err, plen, dlen;
1da177e4 LT	47	struct ipcomp_data *ipcd = x->data;
1da177e4 LT	48	u8 start, scratch;
e4d5b79c	49	struct crypto_comp *tfm;
1da177e4 LT	50	int cpu;
	51
	52	plen = skb->len;
	53	dlen = IPCOMP_SCRATCH_SIZE;
	54	start = skb->data;
	55
	56	cpu = get_cpu();
	57	scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
	58	tfm = *per_cpu_ptr(ipcd->tfms, cpu);
	59
	60	err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
	61	if (err)
	62	goto out;
	63
	64	if (dlen < (plen + sizeof(struct ip_comp_hdr))) {
	65	err = -EINVAL;
	66	goto out;
	67	}
	68
	69	err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
	70	if (err)
	71	goto out;
	72
da952315 HX	73	skb->truesize += dlen - plen;
da952315 HX	74	__skb_put(skb, dlen - plen);
1da177e4	75	memcpy(skb->data, scratch, dlen);
1da177e4 LT	76	out:
	77	put_cpu();
	78	return err;
	79	}
	80
e695633e	81	static int ipcomp_input(struct xfrm_state x, struct sk_buff skb)
1da177e4	82	{
364c6bad	83	int err = -ENOMEM;
1da177e4	84	struct iphdr *iph;
31a4ab93	85	struct ip_comp_hdr *ipch;
1da177e4	86
364c6bad	87	if (skb_linearize_cow(skb))
1da177e4	88	goto out;
1da177e4 LT	89
	90	skb->ip_summed = CHECKSUM_NONE;
	91
	92	/* Remove ipcomp header and decompress original payload */
	93	iph = skb->nh.iph;
31a4ab93 HX	94	ipch = (void *)skb->data;
	95	iph->protocol = ipch->nexthdr;
	96	skb->h.raw = skb->nh.raw + sizeof(*ipch);
	97	__skb_pull(skb, sizeof(*ipch));
1da177e4 LT	98	err = ipcomp_decompress(x, skb);
	99
	100	out:
	101	return err;
	102	}
	103
	104	static int ipcomp_compress(struct xfrm_state x, struct sk_buff skb)
	105	{
	106	int err, plen, dlen, ihlen;
	107	struct iphdr *iph = skb->nh.iph;
	108	struct ipcomp_data *ipcd = x->data;
	109	u8 start, scratch;
e4d5b79c	110	struct crypto_comp *tfm;
1da177e4 LT	111	int cpu;
	112
	113	ihlen = iph->ihl * 4;
	114	plen = skb->len - ihlen;
	115	dlen = IPCOMP_SCRATCH_SIZE;
	116	start = skb->data + ihlen;
	117
	118	cpu = get_cpu();
	119	scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
	120	tfm = *per_cpu_ptr(ipcd->tfms, cpu);
	121
	122	err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
	123	if (err)
	124	goto out;
	125
	126	if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) {
	127	err = -EMSGSIZE;
	128	goto out;
	129	}
	130
	131	memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
	132	put_cpu();
	133
	134	pskb_trim(skb, ihlen + dlen + sizeof(struct ip_comp_hdr));
	135	return 0;
	136
	137	out:
	138	put_cpu();
	139	return err;
	140	}
	141
	142	static int ipcomp_output(struct xfrm_state x, struct sk_buff skb)
	143	{
	144	int err;
	145	struct iphdr *iph;
	146	struct ip_comp_hdr *ipch;
	147	struct ipcomp_data *ipcd = x->data;
	148	int hdr_len = 0;
	149
	150	iph = skb->nh.iph;
	151	iph->tot_len = htons(skb->len);
	152	hdr_len = iph->ihl * 4;
	153	if ((skb->len - hdr_len) < ipcd->threshold) {
	154	/* Don't bother compressing */
	155	goto out_ok;
	156	}
	157
364c6bad	158	if (skb_linearize_cow(skb))
1da177e4	159	goto out_ok;
1da177e4 LT	160
	161	err = ipcomp_compress(x, skb);
	162	iph = skb->nh.iph;
	163
	164	if (err) {
	165	goto out_ok;
	166	}
	167
	168	/* Install ipcomp header, convert into ipcomp datagram. */
	169	iph->tot_len = htons(skb->len);
	170	ipch = (struct ip_comp_hdr )((char )iph + iph->ihl * 4);
	171	ipch->nexthdr = iph->protocol;
	172	ipch->flags = 0;
	173	ipch->cpi = htons((u16 )ntohl(x->id.spi));
	174	iph->protocol = IPPROTO_COMP;
	175	ip_send_check(iph);
	176	return 0;
	177
	178	out_ok:
7e49e6de	179	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	180	ip_send_check(iph);
	181	return 0;
	182	}
	183
	184	static void ipcomp4_err(struct sk_buff *skb, u32 info)
	185	{
	186	u32 spi;
	187	struct iphdr iph = (struct iphdr )skb->data;
	188	struct ip_comp_hdr ipch = (struct ip_comp_hdr )(skb->data+(iph->ihl<<2));
	189	struct xfrm_state *x;
	190
	191	if (skb->h.icmph->type != ICMP_DEST_UNREACH \|\|
	192	skb->h.icmph->code != ICMP_FRAG_NEEDED)
	193	return;
	194
4195f814	195	spi = htonl(ntohs(ipch->cpi));
1da177e4 LT	196	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr,
	197	spi, IPPROTO_COMP, AF_INET);
	198	if (!x)
	199	return;
64ce2073 PM	200	NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%u.%u.%u.%u\n",
64ce2073 PM	201	spi, NIPQUAD(iph->daddr));
1da177e4 LT	202	xfrm_state_put(x);
	203	}
	204
	205	/* We always hold one tunnel user reference to indicate a tunnel */
	206	static struct xfrm_state ipcomp_tunnel_create(struct xfrm_state x)
	207	{
	208	struct xfrm_state *t;
	209
	210	t = xfrm_state_alloc();
	211	if (t == NULL)
	212	goto out;
	213
	214	t->id.proto = IPPROTO_IPIP;
	215	t->id.spi = x->props.saddr.a4;
	216	t->id.daddr.a4 = x->id.daddr.a4;
	217	memcpy(&t->sel, &x->sel, sizeof(t->sel));
	218	t->props.family = AF_INET;
7e49e6de	219	t->props.mode = XFRM_MODE_TUNNEL;
1da177e4 LT	220	t->props.saddr.a4 = x->props.saddr.a4;
1da177e4 LT	221	t->props.flags = x->props.flags;
72cb6962 HX	222
72cb6962 HX	223	if (xfrm_init_state(t))
1da177e4 LT	224	goto error;
1da177e4 LT	225
1da177e4 LT	226	atomic_set(&t->tunnel_users, 1);
	227	out:
	228	return t;
	229
	230	error:
	231	t->km.state = XFRM_STATE_DEAD;
	232	xfrm_state_put(t);
	233	t = NULL;
	234	goto out;
	235	}
	236
	237	/*
4a3e2f71	238	* Must be protected by xfrm_cfg_mutex. State and tunnel user references are
1da177e4 LT	239	* always incremented on success.
	240	*/
	241	static int ipcomp_tunnel_attach(struct xfrm_state *x)
	242	{
	243	int err = 0;
	244	struct xfrm_state *t;
	245
	246	t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr.a4,
	247	x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
	248	if (!t) {
	249	t = ipcomp_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	out:
	260	return err;
	261	}
	262
	263	static void ipcomp_free_scratches(void)
	264	{
	265	int i;
	266	void **scratches;
	267
	268	if (--ipcomp_scratch_users)
	269	return;
	270
	271	scratches = ipcomp_scratches;
	272	if (!scratches)
	273	return;
	274
63903ca6 JJ	275	for_each_possible_cpu(i)
63903ca6 JJ	276	vfree(*per_cpu_ptr(scratches, i));
1da177e4 LT	277
	278	free_percpu(scratches);
	279	}
	280
	281	static void **ipcomp_alloc_scratches(void)
	282	{
	283	int i;
	284	void **scratches;
	285
	286	if (ipcomp_scratch_users++)
	287	return ipcomp_scratches;
	288
	289	scratches = alloc_percpu(void *);
	290	if (!scratches)
	291	return NULL;
	292
	293	ipcomp_scratches = scratches;
	294
6f912042	295	for_each_possible_cpu(i) {
1da177e4 LT	296	void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
	297	if (!scratch)
	298	return NULL;
	299	*per_cpu_ptr(scratches, i) = scratch;
	300	}
	301
	302	return scratches;
	303	}
	304
e4d5b79c	305	static void ipcomp_free_tfms(struct crypto_comp **tfms)
1da177e4 LT	306	{
	307	struct ipcomp_tfms *pos;
	308	int cpu;
	309
	310	list_for_each_entry(pos, &ipcomp_tfms_list, list) {
	311	if (pos->tfms == tfms)
	312	break;
	313	}
	314
	315	BUG_TRAP(pos);
	316
	317	if (--pos->users)
	318	return;
	319
	320	list_del(&pos->list);
	321	kfree(pos);
	322
	323	if (!tfms)
	324	return;
	325
6f912042	326	for_each_possible_cpu(cpu) {
e4d5b79c HX	327	struct crypto_comp tfm = per_cpu_ptr(tfms, cpu);
e4d5b79c HX	328	crypto_free_comp(tfm);
1da177e4 LT	329	}
	330	free_percpu(tfms);
	331	}
	332
e4d5b79c	333	static struct crypto_comp *ipcomp_alloc_tfms(const char alg_name)
1da177e4 LT	334	{
1da177e4 LT	335	struct ipcomp_tfms *pos;
e4d5b79c	336	struct crypto_comp **tfms;
1da177e4 LT	337	int cpu;
	338
	339	/* This can be any valid CPU ID so we don't need locking. */
6fc8b9e7	340	cpu = raw_smp_processor_id();
1da177e4 LT	341
1da177e4 LT	342	list_for_each_entry(pos, &ipcomp_tfms_list, list) {
e4d5b79c	343	struct crypto_comp *tfm;
1da177e4 LT	344
	345	tfms = pos->tfms;
	346	tfm = *per_cpu_ptr(tfms, cpu);
	347
e4d5b79c	348	if (!strcmp(crypto_comp_name(tfm), alg_name)) {
1da177e4 LT	349	pos->users++;
	350	return tfms;
	351	}
	352	}
	353
	354	pos = kmalloc(sizeof(*pos), GFP_KERNEL);
	355	if (!pos)
	356	return NULL;
	357
	358	pos->users = 1;
	359	INIT_LIST_HEAD(&pos->list);
	360	list_add(&pos->list, &ipcomp_tfms_list);
	361
e4d5b79c	362	pos->tfms = tfms = alloc_percpu(struct crypto_comp *);
1da177e4 LT	363	if (!tfms)
	364	goto error;
	365
6f912042	366	for_each_possible_cpu(cpu) {
e4d5b79c HX	367	struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0,
e4d5b79c HX	368	CRYPTO_ALG_ASYNC);
1da177e4 LT	369	if (!tfm)
	370	goto error;
	371	*per_cpu_ptr(tfms, cpu) = tfm;
	372	}
	373
	374	return tfms;
	375
	376	error:
	377	ipcomp_free_tfms(tfms);
	378	return NULL;
	379	}
	380
	381	static void ipcomp_free_data(struct ipcomp_data *ipcd)
	382	{
	383	if (ipcd->tfms)
	384	ipcomp_free_tfms(ipcd->tfms);
	385	ipcomp_free_scratches();
	386	}
	387
	388	static void ipcomp_destroy(struct xfrm_state *x)
	389	{
	390	struct ipcomp_data *ipcd = x->data;
	391	if (!ipcd)
	392	return;
	393	xfrm_state_delete_tunnel(x);
4a3e2f71	394	mutex_lock(&ipcomp_resource_mutex);
1da177e4	395	ipcomp_free_data(ipcd);
4a3e2f71	396	mutex_unlock(&ipcomp_resource_mutex);
1da177e4 LT	397	kfree(ipcd);
	398	}
	399
72cb6962	400	static int ipcomp_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;
0da974f4	414	ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
1da177e4 LT	415	if (!ipcd)
	416	goto out;
	417
1da177e4	418	x->props.header_len = 0;
7e49e6de	419	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	420	x->props.header_len += sizeof(struct iphdr);
1da177e4 LT	421
4a3e2f71	422	mutex_lock(&ipcomp_resource_mutex);
1da177e4 LT	423	if (!ipcomp_alloc_scratches())
	424	goto error;
	425
	426	ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name);
	427	if (!ipcd->tfms)
	428	goto error;
4a3e2f71	429	mutex_unlock(&ipcomp_resource_mutex);
1da177e4	430
7e49e6de	431	if (x->props.mode == XFRM_MODE_TUNNEL) {
1da177e4 LT	432	err = ipcomp_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
	445	error_tunnel:
4a3e2f71	446	mutex_lock(&ipcomp_resource_mutex);
1da177e4 LT	447	error:
1da177e4 LT	448	ipcomp_free_data(ipcd);
4a3e2f71	449	mutex_unlock(&ipcomp_resource_mutex);
1da177e4 LT	450	kfree(ipcd);
	451	goto out;
	452	}
	453
	454	static struct xfrm_type ipcomp_type = {
	455	.description = "IPCOMP4",
	456	.owner = THIS_MODULE,
	457	.proto = IPPROTO_COMP,
	458	.init_state = ipcomp_init_state,
	459	.destructor = ipcomp_destroy,
	460	.input = ipcomp_input,
	461	.output = ipcomp_output
	462	};
	463
	464	static struct net_protocol ipcomp4_protocol = {
	465	.handler = xfrm4_rcv,
	466	.err_handler = ipcomp4_err,
	467	.no_policy = 1,
	468	};
	469
	470	static int __init ipcomp4_init(void)
	471	{
	472	if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
	473	printk(KERN_INFO "ipcomp init: can't add xfrm type\n");
	474	return -EAGAIN;
	475	}
	476	if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
	477	printk(KERN_INFO "ipcomp init: can't add protocol\n");
	478	xfrm_unregister_type(&ipcomp_type, AF_INET);
	479	return -EAGAIN;
	480	}
	481	return 0;
	482	}
	483
	484	static void __exit ipcomp4_fini(void)
	485	{
	486	if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
	487	printk(KERN_INFO "ip ipcomp close: can't remove protocol\n");
	488	if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
	489	printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n");
	490	}
	491
	492	module_init(ipcomp4_init);
	493	module_exit(ipcomp4_fini);
	494
	495	MODULE_LICENSE("GPL");
	496	MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173");
	497	MODULE_AUTHOR("James Morris <[email protected]>");
	498