[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)
{
	struct ipcomp_data *ipcd = x->data;
	const int plen = skb->len;
	int dlen = IPCOMP_SCRATCH_SIZE;
	const u8 *start = skb->data;
	const int cpu = get_cpu();
	u8 *scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
	struct crypto_comp *tfm = *per_cpu_ptr(ipcd->tfms, cpu);
	int 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);
	skb_copy_to_linear_data(skb, 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 = ip_hdr(skb);
	ipch = (void *)skb->data;
	iph->protocol = ipch->nexthdr;
	skb->transport_header = skb->network_header + 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)
{
	struct ipcomp_data *ipcd = x->data;
	const int ihlen = ip_hdrlen(skb);
	const int plen = skb->len - ihlen;
	int dlen = IPCOMP_SCRATCH_SIZE;
	u8 *start = skb->data + ihlen;
	const int cpu = get_cpu();
	u8 *scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
	struct crypto_comp *tfm = *per_cpu_ptr(ipcd->tfms, cpu);
	int 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 ip_comp_hdr *ipch;
	struct ipcomp_data *ipcd = x->data;
	int hdr_len = 0;
	struct iphdr *iph = ip_hdr(skb);

	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 = ip_hdr(skb);

	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)
{
	__be32 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 (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
	    icmp_hdr(skb)->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;
	u8 mode = XFRM_MODE_TUNNEL;

	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;
	if (x->props.mode == XFRM_MODE_BEET)
		mode = x->props.mode;
	t->props.mode = mode;
	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]>");

MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);
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
e905a9ed	8	* Software Foundation; either version 2 of the License, or (at your option)
1da177e4 LT	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	{
1da177e4	46	struct ipcomp_data *ipcd = x->data;
eddc9ec5 ACM	47	const int plen = skb->len;
	48	int dlen = IPCOMP_SCRATCH_SIZE;
	49	const u8 *start = skb->data;
	50	const int cpu = get_cpu();
	51	u8 scratch = per_cpu_ptr(ipcomp_scratches, cpu);
	52	struct crypto_comp tfm = per_cpu_ptr(ipcd->tfms, cpu);
	53	int err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
e905a9ed	54
1da177e4 LT	55	if (err)
	56	goto out;
	57
	58	if (dlen < (plen + sizeof(struct ip_comp_hdr))) {
	59	err = -EINVAL;
	60	goto out;
	61	}
	62
	63	err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
	64	if (err)
	65	goto out;
e905a9ed	66
da952315 HX	67	skb->truesize += dlen - plen;
da952315 HX	68	__skb_put(skb, dlen - plen);
27d7ff46	69	skb_copy_to_linear_data(skb, scratch, dlen);
e905a9ed	70	out:
1da177e4 LT	71	put_cpu();
	72	return err;
	73	}
	74
e695633e	75	static int ipcomp_input(struct xfrm_state x, struct sk_buff skb)
1da177e4	76	{
364c6bad	77	int err = -ENOMEM;
1da177e4	78	struct iphdr *iph;
31a4ab93	79	struct ip_comp_hdr *ipch;
1da177e4	80
364c6bad	81	if (skb_linearize_cow(skb))
e905a9ed	82	goto out;
1da177e4 LT	83
	84	skb->ip_summed = CHECKSUM_NONE;
	85
e905a9ed	86	/* Remove ipcomp header and decompress original payload */
eddc9ec5	87	iph = ip_hdr(skb);
31a4ab93 HX	88	ipch = (void *)skb->data;
31a4ab93 HX	89	iph->protocol = ipch->nexthdr;
b0e380b1	90	skb->transport_header = skb->network_header + sizeof(*ipch);
31a4ab93	91	__skb_pull(skb, sizeof(*ipch));
1da177e4 LT	92	err = ipcomp_decompress(x, skb);
1da177e4 LT	93
e905a9ed	94	out:
1da177e4 LT	95	return err;
	96	}
	97
	98	static int ipcomp_compress(struct xfrm_state x, struct sk_buff skb)
	99	{
1da177e4	100	struct ipcomp_data *ipcd = x->data;
eddc9ec5 ACM	101	const int ihlen = ip_hdrlen(skb);
	102	const int plen = skb->len - ihlen;
	103	int dlen = IPCOMP_SCRATCH_SIZE;
	104	u8 *start = skb->data + ihlen;
	105	const int cpu = get_cpu();
	106	u8 scratch = per_cpu_ptr(ipcomp_scratches, cpu);
	107	struct crypto_comp tfm = per_cpu_ptr(ipcd->tfms, cpu);
	108	int err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
1da177e4	109
1da177e4 LT	110	if (err)
	111	goto out;
	112
	113	if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) {
	114	err = -EMSGSIZE;
	115	goto out;
	116	}
e905a9ed	117
1da177e4 LT	118	memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
	119	put_cpu();
	120
	121	pskb_trim(skb, ihlen + dlen + sizeof(struct ip_comp_hdr));
	122	return 0;
e905a9ed YH	123
e905a9ed YH	124	out:
1da177e4 LT	125	put_cpu();
	126	return err;
	127	}
	128
	129	static int ipcomp_output(struct xfrm_state x, struct sk_buff skb)
	130	{
	131	int err;
1da177e4 LT	132	struct ip_comp_hdr *ipch;
	133	struct ipcomp_data *ipcd = x->data;
	134	int hdr_len = 0;
eddc9ec5	135	struct iphdr *iph = ip_hdr(skb);
1da177e4	136
1da177e4 LT	137	iph->tot_len = htons(skb->len);
	138	hdr_len = iph->ihl * 4;
	139	if ((skb->len - hdr_len) < ipcd->threshold) {
	140	/* Don't bother compressing */
	141	goto out_ok;
	142	}
	143
364c6bad	144	if (skb_linearize_cow(skb))
1da177e4	145	goto out_ok;
e905a9ed	146
1da177e4	147	err = ipcomp_compress(x, skb);
eddc9ec5	148	iph = ip_hdr(skb);
1da177e4 LT	149
	150	if (err) {
	151	goto out_ok;
	152	}
	153
	154	/* Install ipcomp header, convert into ipcomp datagram. */
	155	iph->tot_len = htons(skb->len);
	156	ipch = (struct ip_comp_hdr )((char )iph + iph->ihl * 4);
	157	ipch->nexthdr = iph->protocol;
	158	ipch->flags = 0;
	159	ipch->cpi = htons((u16 )ntohl(x->id.spi));
	160	iph->protocol = IPPROTO_COMP;
	161	ip_send_check(iph);
	162	return 0;
	163
	164	out_ok:
7e49e6de	165	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	166	ip_send_check(iph);
	167	return 0;
	168	}
	169
	170	static void ipcomp4_err(struct sk_buff *skb, u32 info)
	171	{
a94cfd19	172	__be32 spi;
1da177e4 LT	173	struct iphdr iph = (struct iphdr )skb->data;
	174	struct ip_comp_hdr ipch = (struct ip_comp_hdr )(skb->data+(iph->ihl<<2));
	175	struct xfrm_state *x;
	176
88c7664f ACM	177	if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH \|\|
88c7664f ACM	178	icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
1da177e4 LT	179	return;
1da177e4 LT	180
4195f814	181	spi = htonl(ntohs(ipch->cpi));
1da177e4	182	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr,
e905a9ed	183	spi, IPPROTO_COMP, AF_INET);
1da177e4 LT	184	if (!x)
1da177e4 LT	185	return;
64ce2073 PM	186	NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%u.%u.%u.%u\n",
64ce2073 PM	187	spi, NIPQUAD(iph->daddr));
1da177e4 LT	188	xfrm_state_put(x);
	189	}
	190
e905a9ed	191	/* We always hold one tunnel user reference to indicate a tunnel */
1da177e4 LT	192	static struct xfrm_state ipcomp_tunnel_create(struct xfrm_state x)
	193	{
	194	struct xfrm_state *t;
0a69452c	195	u8 mode = XFRM_MODE_TUNNEL;
e905a9ed	196
1da177e4 LT	197	t = xfrm_state_alloc();
	198	if (t == NULL)
	199	goto out;
	200
	201	t->id.proto = IPPROTO_IPIP;
	202	t->id.spi = x->props.saddr.a4;
	203	t->id.daddr.a4 = x->id.daddr.a4;
	204	memcpy(&t->sel, &x->sel, sizeof(t->sel));
	205	t->props.family = AF_INET;
0a69452c DB	206	if (x->props.mode == XFRM_MODE_BEET)
	207	mode = x->props.mode;
	208	t->props.mode = mode;
1da177e4 LT	209	t->props.saddr.a4 = x->props.saddr.a4;
1da177e4 LT	210	t->props.flags = x->props.flags;
72cb6962 HX	211
72cb6962 HX	212	if (xfrm_init_state(t))
1da177e4 LT	213	goto error;
1da177e4 LT	214
1da177e4 LT	215	atomic_set(&t->tunnel_users, 1);
	216	out:
	217	return t;
	218
	219	error:
	220	t->km.state = XFRM_STATE_DEAD;
	221	xfrm_state_put(t);
	222	t = NULL;
	223	goto out;
	224	}
	225
	226	/*
4a3e2f71	227	* Must be protected by xfrm_cfg_mutex. State and tunnel user references are
1da177e4 LT	228	* always incremented on success.
	229	*/
	230	static int ipcomp_tunnel_attach(struct xfrm_state *x)
	231	{
	232	int err = 0;
	233	struct xfrm_state *t;
	234
	235	t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr.a4,
e905a9ed	236	x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
1da177e4 LT	237	if (!t) {
	238	t = ipcomp_tunnel_create(x);
	239	if (!t) {
	240	err = -EINVAL;
	241	goto out;
	242	}
	243	xfrm_state_insert(t);
	244	xfrm_state_hold(t);
	245	}
	246	x->tunnel = t;
	247	atomic_inc(&t->tunnel_users);
	248	out:
	249	return err;
	250	}
	251
	252	static void ipcomp_free_scratches(void)
	253	{
	254	int i;
	255	void **scratches;
	256
	257	if (--ipcomp_scratch_users)
	258	return;
	259
	260	scratches = ipcomp_scratches;
	261	if (!scratches)
	262	return;
	263
63903ca6 JJ	264	for_each_possible_cpu(i)
63903ca6 JJ	265	vfree(*per_cpu_ptr(scratches, i));
1da177e4 LT	266
	267	free_percpu(scratches);
	268	}
	269
	270	static void **ipcomp_alloc_scratches(void)
	271	{
	272	int i;
	273	void **scratches;
	274
	275	if (ipcomp_scratch_users++)
	276	return ipcomp_scratches;
	277
	278	scratches = alloc_percpu(void *);
	279	if (!scratches)
	280	return NULL;
	281
	282	ipcomp_scratches = scratches;
	283
6f912042	284	for_each_possible_cpu(i) {
1da177e4 LT	285	void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
	286	if (!scratch)
	287	return NULL;
	288	*per_cpu_ptr(scratches, i) = scratch;
	289	}
	290
	291	return scratches;
	292	}
	293
e4d5b79c	294	static void ipcomp_free_tfms(struct crypto_comp **tfms)
1da177e4 LT	295	{
	296	struct ipcomp_tfms *pos;
	297	int cpu;
	298
	299	list_for_each_entry(pos, &ipcomp_tfms_list, list) {
	300	if (pos->tfms == tfms)
	301	break;
	302	}
	303
	304	BUG_TRAP(pos);
	305
	306	if (--pos->users)
	307	return;
	308
	309	list_del(&pos->list);
	310	kfree(pos);
	311
	312	if (!tfms)
	313	return;
	314
6f912042	315	for_each_possible_cpu(cpu) {
e4d5b79c HX	316	struct crypto_comp tfm = per_cpu_ptr(tfms, cpu);
e4d5b79c HX	317	crypto_free_comp(tfm);
1da177e4 LT	318	}
	319	free_percpu(tfms);
	320	}
	321
e4d5b79c	322	static struct crypto_comp *ipcomp_alloc_tfms(const char alg_name)
1da177e4 LT	323	{
1da177e4 LT	324	struct ipcomp_tfms *pos;
e4d5b79c	325	struct crypto_comp **tfms;
1da177e4 LT	326	int cpu;
	327
	328	/* This can be any valid CPU ID so we don't need locking. */
6fc8b9e7	329	cpu = raw_smp_processor_id();
1da177e4 LT	330
1da177e4 LT	331	list_for_each_entry(pos, &ipcomp_tfms_list, list) {
e4d5b79c	332	struct crypto_comp *tfm;
1da177e4 LT	333
	334	tfms = pos->tfms;
	335	tfm = *per_cpu_ptr(tfms, cpu);
	336
e4d5b79c	337	if (!strcmp(crypto_comp_name(tfm), alg_name)) {
1da177e4 LT	338	pos->users++;
	339	return tfms;
	340	}
	341	}
	342
	343	pos = kmalloc(sizeof(*pos), GFP_KERNEL);
	344	if (!pos)
	345	return NULL;
	346
	347	pos->users = 1;
	348	INIT_LIST_HEAD(&pos->list);
	349	list_add(&pos->list, &ipcomp_tfms_list);
	350
e4d5b79c	351	pos->tfms = tfms = alloc_percpu(struct crypto_comp *);
1da177e4 LT	352	if (!tfms)
	353	goto error;
	354
6f912042	355	for_each_possible_cpu(cpu) {
e4d5b79c HX	356	struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0,
e4d5b79c HX	357	CRYPTO_ALG_ASYNC);
1da177e4 LT	358	if (!tfm)
	359	goto error;
	360	*per_cpu_ptr(tfms, cpu) = tfm;
	361	}
	362
	363	return tfms;
	364
	365	error:
	366	ipcomp_free_tfms(tfms);
	367	return NULL;
	368	}
	369
	370	static void ipcomp_free_data(struct ipcomp_data *ipcd)
	371	{
	372	if (ipcd->tfms)
	373	ipcomp_free_tfms(ipcd->tfms);
	374	ipcomp_free_scratches();
	375	}
	376
	377	static void ipcomp_destroy(struct xfrm_state *x)
	378	{
	379	struct ipcomp_data *ipcd = x->data;
	380	if (!ipcd)
	381	return;
	382	xfrm_state_delete_tunnel(x);
4a3e2f71	383	mutex_lock(&ipcomp_resource_mutex);
1da177e4	384	ipcomp_free_data(ipcd);
4a3e2f71	385	mutex_unlock(&ipcomp_resource_mutex);
1da177e4 LT	386	kfree(ipcd);
	387	}
	388
72cb6962	389	static int ipcomp_init_state(struct xfrm_state *x)
1da177e4 LT	390	{
	391	int err;
	392	struct ipcomp_data *ipcd;
	393	struct xfrm_algo_desc *calg_desc;
	394
	395	err = -EINVAL;
	396	if (!x->calg)
	397	goto out;
	398
	399	if (x->encap)
	400	goto out;
	401
	402	err = -ENOMEM;
0da974f4	403	ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
1da177e4 LT	404	if (!ipcd)
	405	goto out;
	406
1da177e4	407	x->props.header_len = 0;
7e49e6de	408	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	409	x->props.header_len += sizeof(struct iphdr);
1da177e4 LT	410
4a3e2f71	411	mutex_lock(&ipcomp_resource_mutex);
1da177e4 LT	412	if (!ipcomp_alloc_scratches())
	413	goto error;
	414
	415	ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name);
	416	if (!ipcd->tfms)
	417	goto error;
4a3e2f71	418	mutex_unlock(&ipcomp_resource_mutex);
1da177e4	419
7e49e6de	420	if (x->props.mode == XFRM_MODE_TUNNEL) {
1da177e4 LT	421	err = ipcomp_tunnel_attach(x);
	422	if (err)
	423	goto error_tunnel;
	424	}
	425
	426	calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
	427	BUG_ON(!calg_desc);
	428	ipcd->threshold = calg_desc->uinfo.comp.threshold;
	429	x->data = ipcd;
	430	err = 0;
	431	out:
	432	return err;
	433
	434	error_tunnel:
4a3e2f71	435	mutex_lock(&ipcomp_resource_mutex);
1da177e4 LT	436	error:
1da177e4 LT	437	ipcomp_free_data(ipcd);
4a3e2f71	438	mutex_unlock(&ipcomp_resource_mutex);
1da177e4 LT	439	kfree(ipcd);
	440	goto out;
	441	}
	442
	443	static struct xfrm_type ipcomp_type = {
	444	.description = "IPCOMP4",
	445	.owner = THIS_MODULE,
	446	.proto = IPPROTO_COMP,
	447	.init_state = ipcomp_init_state,
	448	.destructor = ipcomp_destroy,
	449	.input = ipcomp_input,
	450	.output = ipcomp_output
	451	};
	452
	453	static struct net_protocol ipcomp4_protocol = {
	454	.handler = xfrm4_rcv,
	455	.err_handler = ipcomp4_err,
	456	.no_policy = 1,
	457	};
	458
	459	static int __init ipcomp4_init(void)
	460	{
	461	if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
	462	printk(KERN_INFO "ipcomp init: can't add xfrm type\n");
	463	return -EAGAIN;
	464	}
	465	if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
	466	printk(KERN_INFO "ipcomp init: can't add protocol\n");
	467	xfrm_unregister_type(&ipcomp_type, AF_INET);
	468	return -EAGAIN;
	469	}
	470	return 0;
	471	}
	472
	473	static void __exit ipcomp4_fini(void)
	474	{
	475	if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
	476	printk(KERN_INFO "ip ipcomp close: can't remove protocol\n");
	477	if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
	478	printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n");
	479	}
	480
	481	module_init(ipcomp4_init);
	482	module_exit(ipcomp4_fini);
	483
	484	MODULE_LICENSE("GPL");
	485	MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173");
	486	MODULE_AUTHOR("James Morris <[email protected]>");
	487
d3d6dd3a	488	MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);