1// SPDX-License-Identifier: GPL-2.0-or-later
  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 *
 
 
 
 
 
  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>
 20#include <linux/slab.h>
 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
 27struct ipcomp_tfms {
 28	struct list_head list;
 29	struct crypto_comp * __percpu *tfms;
 30	int users;
 31};
 32
 33static DEFINE_MUTEX(ipcomp_resource_mutex);
 34static void * __percpu *ipcomp_scratches;
 35static int ipcomp_scratch_users;
 36static LIST_HEAD(ipcomp_tfms_list);
 37
 38static 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);
 48	int len;
 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
 58	len = dlen - plen;
 59	if (len > skb_tailroom(skb))
 60		len = skb_tailroom(skb);
 61
 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;
 69		struct page *page;
 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;
 76		page = alloc_page(GFP_ATOMIC);
 77
 78		err = -ENOMEM;
 79		if (!page)
 80			goto out;
 81
 82		__skb_frag_set_page(frag, page);
 83
 84		len = PAGE_SIZE;
 85		if (dlen < len)
 86			len = dlen;
 87
 88		skb_frag_off_set(frag, 0);
 89		skb_frag_size_set(frag, len);
 90		memcpy(skb_frag_address(frag), scratch, len);
 91
 
 
 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;
100
101out:
102	put_cpu();
103	return err;
104}
105
106int 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
129out:
130	return err;
131}
132EXPORT_SYMBOL_GPL(ipcomp_input);
133
134static 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;
140	struct crypto_comp *tfm;
141	u8 *scratch;
 
142	int err;
143
144	local_bh_disable();
145	scratch = *this_cpu_ptr(ipcomp_scratches);
146	tfm = *this_cpu_ptr(ipcd->tfms);
147	err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
 
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);
157	local_bh_enable();
158
159	pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
160	return 0;
161
162out:
163	local_bh_enable();
164	return err;
165}
166
167int 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;
193out_ok:
194	skb_push(skb, -skb_network_offset(skb));
195	return 0;
196}
197EXPORT_SYMBOL_GPL(ipcomp_output);
198
199static void ipcomp_free_scratches(void)
200{
201	int i;
202	void * __percpu *scratches;
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
217static void * __percpu *ipcomp_alloc_scratches(void)
218{
219	void * __percpu *scratches;
220	int i;
 
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) {
232		void *scratch;
233
234		scratch = vmalloc_node(IPCOMP_SCRATCH_SIZE, cpu_to_node(i));
235		if (!scratch)
236			return NULL;
237		*per_cpu_ptr(scratches, i) = scratch;
238	}
239
240	return scratches;
241}
242
243static void ipcomp_free_tfms(struct crypto_comp * __percpu *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
253	WARN_ON(!pos);
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
271static struct crypto_comp * __percpu *ipcomp_alloc_tfms(const char *alg_name)
272{
273	struct ipcomp_tfms *pos;
274	struct crypto_comp * __percpu *tfms;
275	int cpu;
276
 
 
277
278	list_for_each_entry(pos, &ipcomp_tfms_list, list) {
279		struct crypto_comp *tfm;
280
281		/* This can be any valid CPU ID so we don't need locking. */
282		tfm = this_cpu_read(*pos->tfms);
283
284		if (!strcmp(crypto_comp_name(tfm), alg_name)) {
285			pos->users++;
286			return pos->tfms;
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
312error:
313	ipcomp_free_tfms(tfms);
314	return NULL;
315}
316
317static 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
324void 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}
335EXPORT_SYMBOL_GPL(ipcomp_destroy);
336
337int 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;
369out:
370	return err;
371
372error:
373	ipcomp_free_data(ipcd);
374	mutex_unlock(&ipcomp_resource_mutex);
375	kfree(ipcd);
376	goto out;
377}
378EXPORT_SYMBOL_GPL(ipcomp_init_state);
379
380MODULE_LICENSE("GPL");
381MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173");
382MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");

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