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

/*
 * IP Payload Compression Protocol (IPComp) - RFC3173.
 *
 * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
 *
 * 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/config.h>
#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_tfm **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 iphdr *iph;
	struct ipcomp_data *ipcd = x->data;
	u8 *start, *scratch;
	struct crypto_tfm *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_put(skb, dlen - plen);
	memcpy(skb->data, scratch, dlen);
	iph = skb->nh.iph;
	iph->tot_len = htons(dlen + iph->ihl * 4);
out:	
	put_cpu();
	return err;
}

static int ipcomp_input(struct xfrm_state *x,
                        struct xfrm_decap_state *decap, struct sk_buff *skb)
{
	u8 nexthdr;
	int err = 0;
	struct iphdr *iph;
	union {
		struct iphdr	iph;
		char 		buf[60];
	} tmp_iph;


	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.iph;
	memcpy(&tmp_iph, iph, iph->ihl * 4);
	nexthdr = *(u8 *)skb->data;
	skb_pull(skb, sizeof(struct ip_comp_hdr));
	skb->nh.raw += sizeof(struct ip_comp_hdr);
	memcpy(skb->nh.raw, &tmp_iph, tmp_iph.iph.ihl * 4);
	iph = skb->nh.iph;
	iph->tot_len = htons(ntohs(iph->tot_len) - sizeof(struct ip_comp_hdr));
	iph->protocol = nexthdr;
	skb->h.raw = skb->data;
	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_tfm *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_is_nonlinear(skb) || skb_cloned(skb)) &&
	    skb_linearize(skb, GFP_ATOMIC) != 0) {
		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)
		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 = ntohl(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 = 1;
	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_cpu(i) {
		void *scratch = *per_cpu_ptr(scratches, i);
		if (scratch)
			vfree(scratch);
	}

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

static struct crypto_tfm **ipcomp_alloc_tfms(const char *alg_name)
{
	struct ipcomp_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, &ipcomp_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, &ipcomp_tfms_list);

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

	for_each_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:
	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 = kmalloc(sizeof(*ipcd), GFP_KERNEL);
	if (!ipcd)
		goto out;

	memset(ipcd, 0, sizeof(*ipcd));
	x->props.header_len = 0;
	if (x->props.mode)
		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) {
		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 <jmorris@intercode.com.au>");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* IP Payload Compression Protocol (IPComp) - RFC3173.
	3	*
	4	* Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
	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	*/
	16	#include <linux/config.h>
	17	#include <linux/module.h>
	18	#include <asm/scatterlist.h>
	19	#include <asm/semaphore.h>
	20	#include <linux/crypto.h>
	21	#include <linux/pfkeyv2.h>
	22	#include <linux/percpu.h>
	23	#include <linux/smp.h>
	24	#include <linux/list.h>
	25	#include <linux/vmalloc.h>
	26	#include <linux/rtnetlink.h>
4a3e2f71	27	#include <linux/mutex.h>
1da177e4 LT	28	#include <net/ip.h>
	29	#include <net/xfrm.h>
	30	#include <net/icmp.h>
	31	#include <net/ipcomp.h>
14c85021	32	#include <net/protocol.h>
1da177e4 LT	33
	34	struct ipcomp_tfms {
	35	struct list_head list;
	36	struct crypto_tfm **tfms;
	37	int users;
	38	};
	39
4a3e2f71	40	static DEFINE_MUTEX(ipcomp_resource_mutex);
1da177e4 LT	41	static void **ipcomp_scratches;
	42	static int ipcomp_scratch_users;
	43	static LIST_HEAD(ipcomp_tfms_list);
	44
	45	static int ipcomp_decompress(struct xfrm_state x, struct sk_buff skb)
	46	{
	47	int err, plen, dlen;
	48	struct iphdr *iph;
	49	struct ipcomp_data *ipcd = x->data;
	50	u8 start, scratch;
	51	struct crypto_tfm *tfm;
	52	int cpu;
	53
	54	plen = skb->len;
	55	dlen = IPCOMP_SCRATCH_SIZE;
	56	start = skb->data;
	57
	58	cpu = get_cpu();
	59	scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
	60	tfm = *per_cpu_ptr(ipcd->tfms, cpu);
	61
	62	err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
	63	if (err)
	64	goto out;
	65
	66	if (dlen < (plen + sizeof(struct ip_comp_hdr))) {
	67	err = -EINVAL;
	68	goto out;
	69	}
	70
	71	err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
	72	if (err)
	73	goto out;
	74
	75	skb_put(skb, dlen - plen);
	76	memcpy(skb->data, scratch, dlen);
	77	iph = skb->nh.iph;
	78	iph->tot_len = htons(dlen + iph->ihl * 4);
	79	out:
	80	put_cpu();
	81	return err;
	82	}
	83
	84	static int ipcomp_input(struct xfrm_state *x,
	85	struct xfrm_decap_state decap, struct sk_buff skb)
	86	{
	87	u8 nexthdr;
	88	int err = 0;
	89	struct iphdr *iph;
	90	union {
	91	struct iphdr iph;
	92	char buf[60];
	93	} tmp_iph;
	94
	95
	96	if ((skb_is_nonlinear(skb) \|\| skb_cloned(skb)) &&
	97	skb_linearize(skb, GFP_ATOMIC) != 0) {
	98	err = -ENOMEM;
	99	goto out;
	100	}
	101
	102	skb->ip_summed = CHECKSUM_NONE;
	103
	104	/* Remove ipcomp header and decompress original payload */
105	iph = skb->nh.iph;
106	memcpy(&tmp_iph, iph, iph->ihl * 4);
107	nexthdr = (u8 )skb->data;
108	skb_pull(skb, sizeof(struct ip_comp_hdr));
109	skb->nh.raw += sizeof(struct ip_comp_hdr);
110	memcpy(skb->nh.raw, &tmp_iph, tmp_iph.iph.ihl * 4);
111	iph = skb->nh.iph;
112	iph->tot_len = htons(ntohs(iph->tot_len) - sizeof(struct ip_comp_hdr));
113	iph->protocol = nexthdr;
114	skb->h.raw = skb->data;
115	err = ipcomp_decompress(x, skb);
116
117	out:
118	return err;
119	}
120
121	static int ipcomp_compress(struct xfrm_state x, struct sk_buff skb)
122	{
123	int err, plen, dlen, ihlen;
124	struct iphdr *iph = skb->nh.iph;
125	struct ipcomp_data *ipcd = x->data;
126	u8 start, scratch;
127	struct crypto_tfm *tfm;
128	int cpu;
129
130	ihlen = iph->ihl * 4;
131	plen = skb->len - ihlen;
132	dlen = IPCOMP_SCRATCH_SIZE;
133	start = skb->data + ihlen;
134
135	cpu = get_cpu();
136	scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
137	tfm = *per_cpu_ptr(ipcd->tfms, cpu);
138
139	err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
140	if (err)
141	goto out;
142
143	if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) {
144	err = -EMSGSIZE;
145	goto out;
146	}
147
148	memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
149	put_cpu();
150
151	pskb_trim(skb, ihlen + dlen + sizeof(struct ip_comp_hdr));
152	return 0;
153
154	out:
155	put_cpu();
156	return err;
157	}
158
159	static int ipcomp_output(struct xfrm_state x, struct sk_buff skb)
160	{
161	int err;
162	struct iphdr *iph;
163	struct ip_comp_hdr *ipch;
164	struct ipcomp_data *ipcd = x->data;
165	int hdr_len = 0;
166
167	iph = skb->nh.iph;
168	iph->tot_len = htons(skb->len);
169	hdr_len = iph->ihl * 4;
170	if ((skb->len - hdr_len) < ipcd->threshold) {
171	/* Don't bother compressing */
172	goto out_ok;
173	}
174
175	if ((skb_is_nonlinear(skb) \|\| skb_cloned(skb)) &&
176	skb_linearize(skb, GFP_ATOMIC) != 0) {
177	goto out_ok;
178	}
179
180	err = ipcomp_compress(x, skb);
181	iph = skb->nh.iph;
182
183	if (err) {
184	goto out_ok;
185	}
186
187	/* Install ipcomp header, convert into ipcomp datagram. */
188	iph->tot_len = htons(skb->len);
189	ipch = (struct ip_comp_hdr )((char )iph + iph->ihl * 4);
190	ipch->nexthdr = iph->protocol;
191	ipch->flags = 0;
192	ipch->cpi = htons((u16 )ntohl(x->id.spi));
193	iph->protocol = IPPROTO_COMP;
194	ip_send_check(iph);
195	return 0;
196
197	out_ok:
198	if (x->props.mode)
199	ip_send_check(iph);
200	return 0;
201	}
202
203	static void ipcomp4_err(struct sk_buff *skb, u32 info)
204	{
205	u32 spi;
206	struct iphdr iph = (struct iphdr )skb->data;
207	struct ip_comp_hdr ipch = (struct ip_comp_hdr )(skb->data+(iph->ihl<<2));
208	struct xfrm_state *x;
209
210	if (skb->h.icmph->type != ICMP_DEST_UNREACH \|\|
211	skb->h.icmph->code != ICMP_FRAG_NEEDED)
212	return;
213
214	spi = ntohl(ntohs(ipch->cpi));
215	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr,
216	spi, IPPROTO_COMP, AF_INET);
217	if (!x)
218	return;
64ce2073 PM	219	NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%u.%u.%u.%u\n",
64ce2073 PM	220	spi, NIPQUAD(iph->daddr));
1da177e4 LT	221	xfrm_state_put(x);
	222	}
	223
	224	/* We always hold one tunnel user reference to indicate a tunnel */
	225	static struct xfrm_state ipcomp_tunnel_create(struct xfrm_state x)
	226	{
	227	struct xfrm_state *t;
	228
	229	t = xfrm_state_alloc();
	230	if (t == NULL)
	231	goto out;
	232
	233	t->id.proto = IPPROTO_IPIP;
	234	t->id.spi = x->props.saddr.a4;
	235	t->id.daddr.a4 = x->id.daddr.a4;
	236	memcpy(&t->sel, &x->sel, sizeof(t->sel));
	237	t->props.family = AF_INET;
	238	t->props.mode = 1;
	239	t->props.saddr.a4 = x->props.saddr.a4;
	240	t->props.flags = x->props.flags;
72cb6962 HX	241
72cb6962 HX	242	if (xfrm_init_state(t))
1da177e4 LT	243	goto error;
1da177e4 LT	244
1da177e4 LT	245	atomic_set(&t->tunnel_users, 1);
	246	out:
	247	return t;
	248
	249	error:
	250	t->km.state = XFRM_STATE_DEAD;
	251	xfrm_state_put(t);
	252	t = NULL;
	253	goto out;
	254	}
	255
	256	/*
4a3e2f71	257	* Must be protected by xfrm_cfg_mutex. State and tunnel user references are
1da177e4 LT	258	* always incremented on success.
	259	*/
	260	static int ipcomp_tunnel_attach(struct xfrm_state *x)
	261	{
	262	int err = 0;
	263	struct xfrm_state *t;
	264
	265	t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr.a4,
	266	x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
	267	if (!t) {
	268	t = ipcomp_tunnel_create(x);
	269	if (!t) {
	270	err = -EINVAL;
	271	goto out;
	272	}
	273	xfrm_state_insert(t);
	274	xfrm_state_hold(t);
	275	}
	276	x->tunnel = t;
	277	atomic_inc(&t->tunnel_users);
	278	out:
	279	return err;
	280	}
	281
	282	static void ipcomp_free_scratches(void)
	283	{
	284	int i;
	285	void **scratches;
	286
	287	if (--ipcomp_scratch_users)
	288	return;
	289
	290	scratches = ipcomp_scratches;
	291	if (!scratches)
	292	return;
	293
	294	for_each_cpu(i) {
	295	void scratch = per_cpu_ptr(scratches, i);
	296	if (scratch)
	297	vfree(scratch);
	298	}
	299
	300	free_percpu(scratches);
	301	}
	302
	303	static void **ipcomp_alloc_scratches(void)
	304	{
	305	int i;
	306	void **scratches;
	307
	308	if (ipcomp_scratch_users++)
	309	return ipcomp_scratches;
	310
	311	scratches = alloc_percpu(void *);
	312	if (!scratches)
	313	return NULL;
	314
	315	ipcomp_scratches = scratches;
	316
	317	for_each_cpu(i) {
	318	void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
	319	if (!scratch)
	320	return NULL;
	321	*per_cpu_ptr(scratches, i) = scratch;
322	}
323
324	return scratches;
325	}
326
327	static void ipcomp_free_tfms(struct crypto_tfm **tfms)
328	{
329	struct ipcomp_tfms *pos;
330	int cpu;
331
332	list_for_each_entry(pos, &ipcomp_tfms_list, list) {
333	if (pos->tfms == tfms)
334	break;
335	}
336
337	BUG_TRAP(pos);
338
339	if (--pos->users)
340	return;
341
342	list_del(&pos->list);
343	kfree(pos);
344
345	if (!tfms)
346	return;
347
348	for_each_cpu(cpu) {
349	struct crypto_tfm tfm = per_cpu_ptr(tfms, cpu);
573dbd95	350	crypto_free_tfm(tfm);
1da177e4 LT	351	}
	352	free_percpu(tfms);
	353	}
	354
	355	static struct crypto_tfm *ipcomp_alloc_tfms(const char alg_name)
	356	{
	357	struct ipcomp_tfms *pos;
	358	struct crypto_tfm **tfms;
	359	int cpu;
	360
	361	/* This can be any valid CPU ID so we don't need locking. */
6fc8b9e7	362	cpu = raw_smp_processor_id();
1da177e4 LT	363
	364	list_for_each_entry(pos, &ipcomp_tfms_list, list) {
	365	struct crypto_tfm *tfm;
	366
	367	tfms = pos->tfms;
	368	tfm = *per_cpu_ptr(tfms, cpu);
	369
	370	if (!strcmp(crypto_tfm_alg_name(tfm), alg_name)) {
	371	pos->users++;
	372	return tfms;
	373	}
	374	}
	375
	376	pos = kmalloc(sizeof(*pos), GFP_KERNEL);
	377	if (!pos)
	378	return NULL;
	379
	380	pos->users = 1;
	381	INIT_LIST_HEAD(&pos->list);
	382	list_add(&pos->list, &ipcomp_tfms_list);
	383
	384	pos->tfms = tfms = alloc_percpu(struct crypto_tfm *);
	385	if (!tfms)
	386	goto error;
	387
	388	for_each_cpu(cpu) {
	389	struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0);
	390	if (!tfm)
	391	goto error;
	392	*per_cpu_ptr(tfms, cpu) = tfm;
	393	}
	394
	395	return tfms;
	396
	397	error:
	398	ipcomp_free_tfms(tfms);
	399	return NULL;
	400	}
	401
	402	static void ipcomp_free_data(struct ipcomp_data *ipcd)
	403	{
	404	if (ipcd->tfms)
	405	ipcomp_free_tfms(ipcd->tfms);
	406	ipcomp_free_scratches();
	407	}
	408
	409	static void ipcomp_destroy(struct xfrm_state *x)
	410	{
	411	struct ipcomp_data *ipcd = x->data;
	412	if (!ipcd)
	413	return;
	414	xfrm_state_delete_tunnel(x);
4a3e2f71	415	mutex_lock(&ipcomp_resource_mutex);
1da177e4	416	ipcomp_free_data(ipcd);
4a3e2f71	417	mutex_unlock(&ipcomp_resource_mutex);
1da177e4 LT	418	kfree(ipcd);
	419	}
	420
72cb6962	421	static int ipcomp_init_state(struct xfrm_state *x)
1da177e4 LT	422	{
	423	int err;
	424	struct ipcomp_data *ipcd;
	425	struct xfrm_algo_desc *calg_desc;
	426
	427	err = -EINVAL;
	428	if (!x->calg)
	429	goto out;
	430
	431	if (x->encap)
	432	goto out;
	433
	434	err = -ENOMEM;
	435	ipcd = kmalloc(sizeof(*ipcd), GFP_KERNEL);
	436	if (!ipcd)
	437	goto out;
	438
	439	memset(ipcd, 0, sizeof(*ipcd));
	440	x->props.header_len = 0;
	441	if (x->props.mode)
	442	x->props.header_len += sizeof(struct iphdr);
	443
4a3e2f71	444	mutex_lock(&ipcomp_resource_mutex);
1da177e4 LT	445	if (!ipcomp_alloc_scratches())
	446	goto error;
	447
	448	ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name);
	449	if (!ipcd->tfms)
	450	goto error;
4a3e2f71	451	mutex_unlock(&ipcomp_resource_mutex);
1da177e4 LT	452
	453	if (x->props.mode) {
	454	err = ipcomp_tunnel_attach(x);
	455	if (err)
	456	goto error_tunnel;
	457	}
	458
	459	calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
	460	BUG_ON(!calg_desc);
	461	ipcd->threshold = calg_desc->uinfo.comp.threshold;
	462	x->data = ipcd;
	463	err = 0;
	464	out:
	465	return err;
	466
	467	error_tunnel:
4a3e2f71	468	mutex_lock(&ipcomp_resource_mutex);
1da177e4 LT	469	error:
1da177e4 LT	470	ipcomp_free_data(ipcd);
4a3e2f71	471	mutex_unlock(&ipcomp_resource_mutex);
1da177e4 LT	472	kfree(ipcd);
	473	goto out;
	474	}
	475
	476	static struct xfrm_type ipcomp_type = {
	477	.description = "IPCOMP4",
	478	.owner = THIS_MODULE,
	479	.proto = IPPROTO_COMP,
	480	.init_state = ipcomp_init_state,
	481	.destructor = ipcomp_destroy,
	482	.input = ipcomp_input,
	483	.output = ipcomp_output
	484	};
	485
	486	static struct net_protocol ipcomp4_protocol = {
	487	.handler = xfrm4_rcv,
	488	.err_handler = ipcomp4_err,
	489	.no_policy = 1,
	490	};
	491
	492	static int __init ipcomp4_init(void)
	493	{
	494	if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
	495	printk(KERN_INFO "ipcomp init: can't add xfrm type\n");
	496	return -EAGAIN;
	497	}
	498	if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
	499	printk(KERN_INFO "ipcomp init: can't add protocol\n");
	500	xfrm_unregister_type(&ipcomp_type, AF_INET);
	501	return -EAGAIN;
	502	}
	503	return 0;
	504	}
	505
	506	static void __exit ipcomp4_fini(void)
	507	{
	508	if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
	509	printk(KERN_INFO "ip ipcomp close: can't remove protocol\n");
	510	if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
	511	printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n");
	512	}
	513
	514	module_init(ipcomp4_init);
	515	module_exit(ipcomp4_fini);
	516
	517	MODULE_LICENSE("GPL");
	518	MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173");
	519	MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
	520