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

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * 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>
 *
 * Todo:
 *   - Tunable compression parameters.
 *   - Compression stats.
 *   - Adaptive compression.
 */

#include <linux/crypto.h>
#include <linux/err.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/percpu.h>
#include <linux/slab.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 * __percpu *tfms;
	int users;
};

static DEFINE_MUTEX(ipcomp_resource_mutex);
static void * __percpu *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_put(skb, len);

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

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

		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;
		page = alloc_page(GFP_ATOMIC);

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

		__skb_frag_set_page(frag, page);

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

		skb_frag_off_set(frag, 0);
		skb_frag_size_set(frag, len);
		memcpy(skb_frag_address(frag), scratch, 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;
	struct crypto_comp *tfm;
	u8 *scratch;
	int err;

	local_bh_disable();
	scratch = *this_cpu_ptr(ipcomp_scratches);
	tfm = *this_cpu_ptr(ipcd->tfms);
	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);
	local_bh_enable();

	pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
	return 0;

out:
	local_bh_enable();
	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 * __percpu *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 * __percpu *ipcomp_alloc_scratches(void)
{
	void * __percpu *scratches;
	int i;

	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;

		scratch = vmalloc_node(IPCOMP_SCRATCH_SIZE, cpu_to_node(i));
		if (!scratch)
			return NULL;
		*per_cpu_ptr(scratches, i) = scratch;
	}

	return scratches;
}

static void ipcomp_free_tfms(struct crypto_comp * __percpu *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 * __percpu *ipcomp_alloc_tfms(const char *alg_name)
{
	struct ipcomp_tfms *pos;
	struct crypto_comp * __percpu *tfms;
	int cpu;


	list_for_each_entry(pos, &ipcomp_tfms_list, list) {
		struct crypto_comp *tfm;

		/* This can be any valid CPU ID so we don't need locking. */
		tfm = this_cpu_read(*pos->tfms);

		if (!strcmp(crypto_comp_name(tfm), alg_name)) {
			pos->users++;
			return pos->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
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
6fccab67 HX	2	/*
	3	* IP Payload Compression Protocol (IPComp) - RFC3173.
	4	*
	5	* Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
	6	* Copyright (c) 2003-2008 Herbert Xu <herbert@gondor.apana.org.au>
	7	*
6fccab67 HX	8	* Todo:
	9	* - Tunable compression parameters.
	10	* - Compression stats.
	11	* - Adaptive compression.
	12	*/
	13
	14	#include <linux/crypto.h>
	15	#include <linux/err.h>
	16	#include <linux/list.h>
	17	#include <linux/module.h>
	18	#include <linux/mutex.h>
	19	#include <linux/percpu.h>
5a0e3ad6	20	#include <linux/slab.h>
6fccab67 HX	21	#include <linux/smp.h>
	22	#include <linux/vmalloc.h>
	23	#include <net/ip.h>
	24	#include <net/ipcomp.h>
	25	#include <net/xfrm.h>
	26
	27	struct ipcomp_tfms {
	28	struct list_head list;
7d720c3e	29	struct crypto_comp * __percpu *tfms;
6fccab67 HX	30	int users;
	31	};
	32
	33	static DEFINE_MUTEX(ipcomp_resource_mutex);
7d720c3e	34	static void * __percpu *ipcomp_scratches;
6fccab67 HX	35	static int ipcomp_scratch_users;
	36	static LIST_HEAD(ipcomp_tfms_list);
	37
	38	static int ipcomp_decompress(struct xfrm_state x, struct sk_buff skb)
	39	{
	40	struct ipcomp_data *ipcd = x->data;
	41	const int plen = skb->len;
	42	int dlen = IPCOMP_SCRATCH_SIZE;
	43	const u8 *start = skb->data;
	44	const int cpu = get_cpu();
	45	u8 scratch = per_cpu_ptr(ipcomp_scratches, cpu);
	46	struct crypto_comp tfm = per_cpu_ptr(ipcd->tfms, cpu);
	47	int err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
7d7e5a60	48	int len;
6fccab67 HX	49
	50	if (err)
	51	goto out;
	52
	53	if (dlen < (plen + sizeof(struct ip_comp_hdr))) {
	54	err = -EINVAL;
	55	goto out;
	56	}
	57
7d7e5a60 HX	58	len = dlen - plen;
	59	if (len > skb_tailroom(skb))
	60	len = skb_tailroom(skb);
	61
7d7e5a60 HX	62	__skb_put(skb, len);
	63
	64	len += plen;
	65	skb_copy_to_linear_data(skb, scratch, len);
	66
	67	while ((scratch += len, dlen -= len) > 0) {
	68	skb_frag_t *frag;
804cf14e	69	struct page *page;
7d7e5a60 HX	70
	71	err = -EMSGSIZE;
	72	if (WARN_ON(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS))
	73	goto out;
	74
	75	frag = skb_shinfo(skb)->frags + skb_shinfo(skb)->nr_frags;
804cf14e	76	page = alloc_page(GFP_ATOMIC);
7d7e5a60 HX	77
7d7e5a60 HX	78	err = -ENOMEM;
804cf14e	79	if (!page)
7d7e5a60 HX	80	goto out;
7d7e5a60 HX	81
804cf14e IC	82	__skb_frag_set_page(frag, page);
804cf14e IC	83
7d7e5a60 HX	84	len = PAGE_SIZE;
	85	if (dlen < len)
	86	len = dlen;
	87
b54c9d5b	88	skb_frag_off_set(frag, 0);
9e903e08	89	skb_frag_size_set(frag, len);
804cf14e IC	90	memcpy(skb_frag_address(frag), scratch, len);
804cf14e IC	91
7d7e5a60 HX	92	skb->truesize += len;
	93	skb->data_len += len;
	94	skb->len += len;
	95
	96	skb_shinfo(skb)->nr_frags++;
	97	}
	98
	99	err = 0;
6fccab67	100
6fccab67 HX	101	out:
	102	put_cpu();
	103	return err;
	104	}
	105
	106	int ipcomp_input(struct xfrm_state x, struct sk_buff skb)
	107	{
	108	int nexthdr;
	109	int err = -ENOMEM;
	110	struct ip_comp_hdr *ipch;
	111
	112	if (skb_linearize_cow(skb))
	113	goto out;
	114
	115	skb->ip_summed = CHECKSUM_NONE;
	116
	117	/* Remove ipcomp header and decompress original payload */
	118	ipch = (void *)skb->data;
	119	nexthdr = ipch->nexthdr;
	120
	121	skb->transport_header = skb->network_header + sizeof(*ipch);
	122	__skb_pull(skb, sizeof(*ipch));
	123	err = ipcomp_decompress(x, skb);
	124	if (err)
	125	goto out;
	126
	127	err = nexthdr;
	128
	129	out:
	130	return err;
	131	}
	132	EXPORT_SYMBOL_GPL(ipcomp_input);
	133
	134	static int ipcomp_compress(struct xfrm_state x, struct sk_buff skb)
	135	{
	136	struct ipcomp_data *ipcd = x->data;
	137	const int plen = skb->len;
	138	int dlen = IPCOMP_SCRATCH_SIZE;
	139	u8 *start = skb->data;
12e35946 MK	140	struct crypto_comp *tfm;
12e35946 MK	141	u8 *scratch;
6fccab67 HX	142	int err;
	143
	144	local_bh_disable();
12e35946 MK	145	scratch = *this_cpu_ptr(ipcomp_scratches);
12e35946 MK	146	tfm = *this_cpu_ptr(ipcd->tfms);
6fccab67	147	err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
6fccab67 HX	148	if (err)
	149	goto out;
	150
	151	if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) {
	152	err = -EMSGSIZE;
	153	goto out;
	154	}
	155
	156	memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
12e35946	157	local_bh_enable();
6fccab67 HX	158
	159	pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
	160	return 0;
	161
	162	out:
12e35946	163	local_bh_enable();
6fccab67 HX	164	return err;
	165	}
	166
	167	int ipcomp_output(struct xfrm_state x, struct sk_buff skb)
	168	{
	169	int err;
	170	struct ip_comp_hdr *ipch;
	171	struct ipcomp_data *ipcd = x->data;
	172
	173	if (skb->len < ipcd->threshold) {
	174	/* Don't bother compressing */
	175	goto out_ok;
	176	}
	177
	178	if (skb_linearize_cow(skb))
	179	goto out_ok;
	180
	181	err = ipcomp_compress(x, skb);
	182
	183	if (err) {
	184	goto out_ok;
	185	}
	186
	187	/* Install ipcomp header, convert into ipcomp datagram. */
	188	ipch = ip_comp_hdr(skb);
	189	ipch->nexthdr = *skb_mac_header(skb);
	190	ipch->flags = 0;
	191	ipch->cpi = htons((u16 )ntohl(x->id.spi));
	192	*skb_mac_header(skb) = IPPROTO_COMP;
	193	out_ok:
	194	skb_push(skb, -skb_network_offset(skb));
	195	return 0;
	196	}
	197	EXPORT_SYMBOL_GPL(ipcomp_output);
	198
	199	static void ipcomp_free_scratches(void)
	200	{
	201	int i;
7d720c3e	202	void * __percpu *scratches;
6fccab67 HX	203
	204	if (--ipcomp_scratch_users)
	205	return;
	206
	207	scratches = ipcomp_scratches;
	208	if (!scratches)
	209	return;
	210
	211	for_each_possible_cpu(i)
	212	vfree(*per_cpu_ptr(scratches, i));
	213
	214	free_percpu(scratches);
	215	}
	216
7d720c3e	217	static void * __percpu *ipcomp_alloc_scratches(void)
6fccab67	218	{
7d720c3e	219	void * __percpu *scratches;
5cf4eb54	220	int i;
6fccab67 HX	221
	222	if (ipcomp_scratch_users++)
	223	return ipcomp_scratches;
	224
	225	scratches = alloc_percpu(void *);
	226	if (!scratches)
	227	return NULL;
	228
	229	ipcomp_scratches = scratches;
	230
	231	for_each_possible_cpu(i) {
5cf4eb54 ED	232	void *scratch;
	233
	234	scratch = vmalloc_node(IPCOMP_SCRATCH_SIZE, cpu_to_node(i));
6fccab67 HX	235	if (!scratch)
	236	return NULL;
	237	*per_cpu_ptr(scratches, i) = scratch;
	238	}
	239
	240	return scratches;
	241	}
	242
7d720c3e	243	static void ipcomp_free_tfms(struct crypto_comp * __percpu *tfms)
6fccab67 HX	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
7d720c3e	271	static struct crypto_comp * __percpu ipcomp_alloc_tfms(const char alg_name)
6fccab67 HX	272	{
6fccab67 HX	273	struct ipcomp_tfms *pos;
7d720c3e	274	struct crypto_comp * __percpu *tfms;
6fccab67 HX	275	int cpu;
6fccab67 HX	276
6fccab67 HX	277
	278	list_for_each_entry(pos, &ipcomp_tfms_list, list) {
	279	struct crypto_comp *tfm;
	280
f7c83bcb	281	/* This can be any valid CPU ID so we don't need locking. */
0dcd7876	282	tfm = this_cpu_read(*pos->tfms);
6fccab67 HX	283
	284	if (!strcmp(crypto_comp_name(tfm), alg_name)) {
	285	pos->users++;
f7c83bcb	286	return pos->tfms;
6fccab67 HX	287	}
	288	}
	289
	290	pos = kmalloc(sizeof(*pos), GFP_KERNEL);
	291	if (!pos)
	292	return NULL;
	293
	294	pos->users = 1;
	295	INIT_LIST_HEAD(&pos->list);
	296	list_add(&pos->list, &ipcomp_tfms_list);
	297
	298	pos->tfms = tfms = alloc_percpu(struct crypto_comp *);
	299	if (!tfms)
	300	goto error;
	301
	302	for_each_possible_cpu(cpu) {
	303	struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0,
	304	CRYPTO_ALG_ASYNC);
	305	if (IS_ERR(tfm))
	306	goto error;
	307	*per_cpu_ptr(tfms, cpu) = tfm;
	308	}
	309
	310	return tfms;
	311
	312	error:
	313	ipcomp_free_tfms(tfms);
	314	return NULL;
	315	}
	316
	317	static void ipcomp_free_data(struct ipcomp_data *ipcd)
	318	{
	319	if (ipcd->tfms)
	320	ipcomp_free_tfms(ipcd->tfms);
	321	ipcomp_free_scratches();
	322	}
	323
	324	void ipcomp_destroy(struct xfrm_state *x)
	325	{
	326	struct ipcomp_data *ipcd = x->data;
	327	if (!ipcd)
	328	return;
	329	xfrm_state_delete_tunnel(x);
	330	mutex_lock(&ipcomp_resource_mutex);
	331	ipcomp_free_data(ipcd);
	332	mutex_unlock(&ipcomp_resource_mutex);
	333	kfree(ipcd);
	334	}
	335	EXPORT_SYMBOL_GPL(ipcomp_destroy);
	336
	337	int ipcomp_init_state(struct xfrm_state *x)
	338	{
	339	int err;
	340	struct ipcomp_data *ipcd;
	341	struct xfrm_algo_desc *calg_desc;
	342
	343	err = -EINVAL;
	344	if (!x->calg)
	345	goto out;
	346
	347	if (x->encap)
	348	goto out;
	349
	350	err = -ENOMEM;
351	ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
352	if (!ipcd)
353	goto out;
354
355	mutex_lock(&ipcomp_resource_mutex);
356	if (!ipcomp_alloc_scratches())
357	goto error;
358
359	ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name);
360	if (!ipcd->tfms)
361	goto error;
362	mutex_unlock(&ipcomp_resource_mutex);
363
364	calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
365	BUG_ON(!calg_desc);
366	ipcd->threshold = calg_desc->uinfo.comp.threshold;
367	x->data = ipcd;
368	err = 0;
369	out:
370	return err;
371
372	error:
373	ipcomp_free_data(ipcd);
374	mutex_unlock(&ipcomp_resource_mutex);
375	kfree(ipcd);
376	goto out;
377	}
378	EXPORT_SYMBOL_GPL(ipcomp_init_state);
379
380	MODULE_LICENSE("GPL");
381	MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173");
382	MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");