[linux-2.6-block.git] / net / xfrm / xfrm_ipcomp.c

/*
 * IP Payload Compression Protocol (IPComp) - RFC3173.
 *
 * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
 * Copyright (c) 2003-2008 Herbert Xu <herbert@gondor.apana.org.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/crypto.h>
#include <linux/err.h>
#include <linux/gfp.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/percpu.h>
#include <linux/smp.h>
#include <linux/vmalloc.h>
#include <net/ip.h>
#include <net/ipcomp.h>
#include <net/xfrm.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);
	int len;

	if (err)
		goto out;

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

	len = dlen - plen;
	if (len > skb_tailroom(skb))
		len = skb_tailroom(skb);

	skb->truesize += len;
	__skb_put(skb, len);

	len += plen;
	skb_copy_to_linear_data(skb, scratch, len);

	while ((scratch += len, dlen -= len) > 0) {
		skb_frag_t *frag;

		err = -EMSGSIZE;
		if (WARN_ON(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS))
			goto out;

		frag = skb_shinfo(skb)->frags + skb_shinfo(skb)->nr_frags;
		frag->page = alloc_page(GFP_ATOMIC);

		err = -ENOMEM;
		if (!frag->page)
			goto out;

		len = PAGE_SIZE;
		if (dlen < len)
			len = dlen;

		memcpy(page_address(frag->page), scratch, len);

		frag->page_offset = 0;
		frag->size = len;
		skb->truesize += len;
		skb->data_len += len;
		skb->len += len;

		skb_shinfo(skb)->nr_frags++;
	}

	err = 0;

out:
	put_cpu();
	return err;
}

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

	if (skb_linearize_cow(skb))
		goto out;

	skb->ip_summed = CHECKSUM_NONE;

	/* Remove ipcomp header and decompress original payload */
	ipch = (void *)skb->data;
	nexthdr = ipch->nexthdr;

	skb->transport_header = skb->network_header + sizeof(*ipch);
	__skb_pull(skb, sizeof(*ipch));
	err = ipcomp_decompress(x, skb);
	if (err)
		goto out;

	err = nexthdr;

out:
	return err;
}
EXPORT_SYMBOL_GPL(ipcomp_input);

static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb)
{
	struct ipcomp_data *ipcd = x->data;
	const int plen = skb->len;
	int dlen = IPCOMP_SCRATCH_SIZE;
	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;

	local_bh_disable();
	err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
	local_bh_enable();
	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, dlen + sizeof(struct ip_comp_hdr));
	return 0;

out:
	put_cpu();
	return err;
}

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

	if (skb->len < ipcd->threshold) {
		/* Don't bother compressing */
		goto out_ok;
	}

	if (skb_linearize_cow(skb))
		goto out_ok;

	err = ipcomp_compress(x, skb);

	if (err) {
		goto out_ok;
	}

	/* Install ipcomp header, convert into ipcomp datagram. */
	ipch = ip_comp_hdr(skb);
	ipch->nexthdr = *skb_mac_header(skb);
	ipch->flags = 0;
	ipch->cpi = htons((u16 )ntohl(x->id.spi));
	*skb_mac_header(skb) = IPPROTO_COMP;
out_ok:
	skb_push(skb, -skb_network_offset(skb));
	return 0;
}
EXPORT_SYMBOL_GPL(ipcomp_output);

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;
	}

	WARN_ON(!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 (IS_ERR(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();
}

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);
}
EXPORT_SYMBOL_GPL(ipcomp_destroy);

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;

	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);

	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:
	ipcomp_free_data(ipcd);
	mutex_unlock(&ipcomp_resource_mutex);
	kfree(ipcd);
	goto out;
}
EXPORT_SYMBOL_GPL(ipcomp_init_state);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173");
MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
Commit	Line	Data
6fccab67 HX	1	/*
	2	* IP Payload Compression Protocol (IPComp) - RFC3173.
	3	*
	4	* Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
	5	* Copyright (c) 2003-2008 Herbert Xu <herbert@gondor.apana.org.au>
	6	*
	7	* This program is free software; you can redistribute it and/or modify it
	8	* under the terms of the GNU General Public License as published by the Free
	9	* Software Foundation; either version 2 of the License, or (at your option)
	10	* any later version.
	11	*
	12	* Todo:
	13	* - Tunable compression parameters.
	14	* - Compression stats.
	15	* - Adaptive compression.
	16	*/
	17
	18	#include <linux/crypto.h>
	19	#include <linux/err.h>
7d7e5a60	20	#include <linux/gfp.h>
6fccab67 HX	21	#include <linux/list.h>
	22	#include <linux/module.h>
	23	#include <linux/mutex.h>
	24	#include <linux/percpu.h>
6fccab67 HX	25	#include <linux/smp.h>
	26	#include <linux/vmalloc.h>
	27	#include <net/ip.h>
	28	#include <net/ipcomp.h>
	29	#include <net/xfrm.h>
	30
	31	struct ipcomp_tfms {
	32	struct list_head list;
	33	struct crypto_comp **tfms;
	34	int users;
	35	};
	36
	37	static DEFINE_MUTEX(ipcomp_resource_mutex);
	38	static void **ipcomp_scratches;
	39	static int ipcomp_scratch_users;
	40	static LIST_HEAD(ipcomp_tfms_list);
	41
	42	static int ipcomp_decompress(struct xfrm_state x, struct sk_buff skb)
	43	{
	44	struct ipcomp_data *ipcd = x->data;
	45	const int plen = skb->len;
	46	int dlen = IPCOMP_SCRATCH_SIZE;
	47	const u8 *start = skb->data;
	48	const int cpu = get_cpu();
	49	u8 scratch = per_cpu_ptr(ipcomp_scratches, cpu);
	50	struct crypto_comp tfm = per_cpu_ptr(ipcd->tfms, cpu);
	51	int err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
7d7e5a60	52	int len;
6fccab67 HX	53
	54	if (err)
	55	goto out;
	56
	57	if (dlen < (plen + sizeof(struct ip_comp_hdr))) {
	58	err = -EINVAL;
	59	goto out;
	60	}
	61
7d7e5a60 HX	62	len = dlen - plen;
	63	if (len > skb_tailroom(skb))
	64	len = skb_tailroom(skb);
	65
	66	skb->truesize += len;
	67	__skb_put(skb, len);
	68
	69	len += plen;
	70	skb_copy_to_linear_data(skb, scratch, len);
	71
	72	while ((scratch += len, dlen -= len) > 0) {
	73	skb_frag_t *frag;
	74
	75	err = -EMSGSIZE;
	76	if (WARN_ON(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS))
	77	goto out;
	78
	79	frag = skb_shinfo(skb)->frags + skb_shinfo(skb)->nr_frags;
	80	frag->page = alloc_page(GFP_ATOMIC);
	81
	82	err = -ENOMEM;
	83	if (!frag->page)
	84	goto out;
	85
	86	len = PAGE_SIZE;
	87	if (dlen < len)
	88	len = dlen;
	89
	90	memcpy(page_address(frag->page), scratch, len);
	91
	92	frag->page_offset = 0;
	93	frag->size = len;
	94	skb->truesize += len;
	95	skb->data_len += len;
	96	skb->len += len;
	97
	98	skb_shinfo(skb)->nr_frags++;
	99	}
	100
	101	err = 0;
6fccab67	102
6fccab67 HX	103	out:
	104	put_cpu();
	105	return err;
	106	}
	107
	108	int ipcomp_input(struct xfrm_state x, struct sk_buff skb)
	109	{
	110	int nexthdr;
	111	int err = -ENOMEM;
	112	struct ip_comp_hdr *ipch;
	113
	114	if (skb_linearize_cow(skb))
	115	goto out;
	116
	117	skb->ip_summed = CHECKSUM_NONE;
	118
	119	/* Remove ipcomp header and decompress original payload */
	120	ipch = (void *)skb->data;
	121	nexthdr = ipch->nexthdr;
	122
	123	skb->transport_header = skb->network_header + sizeof(*ipch);
	124	__skb_pull(skb, sizeof(*ipch));
	125	err = ipcomp_decompress(x, skb);
	126	if (err)
	127	goto out;
	128
	129	err = nexthdr;
	130
	131	out:
	132	return err;
	133	}
	134	EXPORT_SYMBOL_GPL(ipcomp_input);
	135
	136	static int ipcomp_compress(struct xfrm_state x, struct sk_buff skb)
	137	{
	138	struct ipcomp_data *ipcd = x->data;
	139	const int plen = skb->len;
	140	int dlen = IPCOMP_SCRATCH_SIZE;
	141	u8 *start = skb->data;
	142	const int cpu = get_cpu();
	143	u8 scratch = per_cpu_ptr(ipcomp_scratches, cpu);
	144	struct crypto_comp tfm = per_cpu_ptr(ipcd->tfms, cpu);
	145	int err;
	146
	147	local_bh_disable();
	148	err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
	149	local_bh_enable();
	150	if (err)
	151	goto out;
	152
	153	if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) {
	154	err = -EMSGSIZE;
	155	goto out;
	156	}
	157
	158	memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
	159	put_cpu();
	160
	161	pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
	162	return 0;
	163
	164	out:
	165	put_cpu();
	166	return err;
167	}
168
169	int ipcomp_output(struct xfrm_state x, struct sk_buff skb)
170	{
171	int err;
172	struct ip_comp_hdr *ipch;
173	struct ipcomp_data *ipcd = x->data;
174
175	if (skb->len < ipcd->threshold) {
176	/* Don't bother compressing */
177	goto out_ok;
178	}
179
180	if (skb_linearize_cow(skb))
181	goto out_ok;
182
183	err = ipcomp_compress(x, skb);
184
185	if (err) {
186	goto out_ok;
187	}
188
189	/* Install ipcomp header, convert into ipcomp datagram. */
190	ipch = ip_comp_hdr(skb);
191	ipch->nexthdr = *skb_mac_header(skb);
192	ipch->flags = 0;
193	ipch->cpi = htons((u16 )ntohl(x->id.spi));
194	*skb_mac_header(skb) = IPPROTO_COMP;
195	out_ok:
196	skb_push(skb, -skb_network_offset(skb));
197	return 0;
198	}
199	EXPORT_SYMBOL_GPL(ipcomp_output);
200
201	static void ipcomp_free_scratches(void)
202	{
203	int i;
204	void **scratches;
205
206	if (--ipcomp_scratch_users)
207	return;
208
209	scratches = ipcomp_scratches;
210	if (!scratches)
211	return;
212
213	for_each_possible_cpu(i)
214	vfree(*per_cpu_ptr(scratches, i));
215
216	free_percpu(scratches);
217	}
218
219	static void **ipcomp_alloc_scratches(void)
220	{
221	int i;
222	void **scratches;
223
224	if (ipcomp_scratch_users++)
225	return ipcomp_scratches;
226
227	scratches = alloc_percpu(void *);
228	if (!scratches)
229	return NULL;
230
231	ipcomp_scratches = scratches;
232
233	for_each_possible_cpu(i) {
234	void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
235	if (!scratch)
236	return NULL;
237	*per_cpu_ptr(scratches, i) = scratch;
238	}
239
240	return scratches;
241	}
242
243	static void ipcomp_free_tfms(struct crypto_comp **tfms)
244	{
245	struct ipcomp_tfms *pos;
246	int cpu;
247
248	list_for_each_entry(pos, &ipcomp_tfms_list, list) {
249	if (pos->tfms == tfms)
250	break;
251	}
252
547b792c	253	WARN_ON(!pos);
6fccab67 HX	254
	255	if (--pos->users)
	256	return;
	257
	258	list_del(&pos->list);
	259	kfree(pos);
	260
	261	if (!tfms)
	262	return;
	263
	264	for_each_possible_cpu(cpu) {
	265	struct crypto_comp tfm = per_cpu_ptr(tfms, cpu);
	266	crypto_free_comp(tfm);
	267	}
	268	free_percpu(tfms);
	269	}
	270
	271	static struct crypto_comp *ipcomp_alloc_tfms(const char alg_name)
	272	{
	273	struct ipcomp_tfms *pos;
	274	struct crypto_comp **tfms;
	275	int cpu;
	276
	277	/* This can be any valid CPU ID so we don't need locking. */
	278	cpu = raw_smp_processor_id();
	279
	280	list_for_each_entry(pos, &ipcomp_tfms_list, list) {
	281	struct crypto_comp *tfm;
	282
	283	tfms = pos->tfms;
	284	tfm = *per_cpu_ptr(tfms, cpu);
	285
	286	if (!strcmp(crypto_comp_name(tfm), alg_name)) {
	287	pos->users++;
	288	return tfms;
	289	}
	290	}
	291
	292	pos = kmalloc(sizeof(*pos), GFP_KERNEL);
	293	if (!pos)
	294	return NULL;
	295
	296	pos->users = 1;
	297	INIT_LIST_HEAD(&pos->list);
	298	list_add(&pos->list, &ipcomp_tfms_list);
	299
	300	pos->tfms = tfms = alloc_percpu(struct crypto_comp *);
	301	if (!tfms)
	302	goto error;
	303
	304	for_each_possible_cpu(cpu) {
	305	struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0,
	306	CRYPTO_ALG_ASYNC);
	307	if (IS_ERR(tfm))
	308	goto error;
	309	*per_cpu_ptr(tfms, cpu) = tfm;
	310	}
	311
	312	return tfms;
	313
	314	error:
	315	ipcomp_free_tfms(tfms);
	316	return NULL;
	317	}
318
319	static void ipcomp_free_data(struct ipcomp_data *ipcd)
320	{
321	if (ipcd->tfms)
322	ipcomp_free_tfms(ipcd->tfms);
323	ipcomp_free_scratches();
324	}
325
326	void ipcomp_destroy(struct xfrm_state *x)
327	{
328	struct ipcomp_data *ipcd = x->data;
329	if (!ipcd)
330	return;
331	xfrm_state_delete_tunnel(x);
332	mutex_lock(&ipcomp_resource_mutex);
333	ipcomp_free_data(ipcd);
334	mutex_unlock(&ipcomp_resource_mutex);
335	kfree(ipcd);
336	}
337	EXPORT_SYMBOL_GPL(ipcomp_destroy);
338
339	int ipcomp_init_state(struct xfrm_state *x)
340	{
341	int err;
342	struct ipcomp_data *ipcd;
343	struct xfrm_algo_desc *calg_desc;
344
345	err = -EINVAL;
346	if (!x->calg)
347	goto out;
348
349	if (x->encap)
350	goto out;
351
352	err = -ENOMEM;
353	ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
354	if (!ipcd)
355	goto out;
356
357	mutex_lock(&ipcomp_resource_mutex);
358	if (!ipcomp_alloc_scratches())
359	goto error;
360
361	ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name);
362	if (!ipcd->tfms)
363	goto error;
364	mutex_unlock(&ipcomp_resource_mutex);
365
366	calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
367	BUG_ON(!calg_desc);
368	ipcd->threshold = calg_desc->uinfo.comp.threshold;
369	x->data = ipcd;
370	err = 0;
371	out:
372	return err;
373
374	error:
375	ipcomp_free_data(ipcd);
376	mutex_unlock(&ipcomp_resource_mutex);
377	kfree(ipcd);
378	goto out;
379	}
380	EXPORT_SYMBOL_GPL(ipcomp_init_state);
381
382	MODULE_LICENSE("GPL");
383	MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173");
384	MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");