[deliverable/linux.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/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/percpu.h>
#include <linux/rtnetlink.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);

	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;
}

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;
	}

	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 (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>
	20	#include <linux/list.h>
	21	#include <linux/module.h>
	22	#include <linux/mutex.h>
	23	#include <linux/percpu.h>
	24	#include <linux/rtnetlink.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
	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);
	52
	53	if (err)
	54	goto out;
	55
	56	if (dlen < (plen + sizeof(struct ip_comp_hdr))) {
	57	err = -EINVAL;
	58	goto out;
	59	}
	60
	61	err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
	62	if (err)
	63	goto out;
	64
65	skb->truesize += dlen - plen;
66	__skb_put(skb, dlen - plen);
67	skb_copy_to_linear_data(skb, scratch, dlen);
68	out:
69	put_cpu();
70	return err;
71	}
72
73	int ipcomp_input(struct xfrm_state x, struct sk_buff skb)
74	{
75	int nexthdr;
76	int err = -ENOMEM;
77	struct ip_comp_hdr *ipch;
78
79	if (skb_linearize_cow(skb))
80	goto out;
81
82	skb->ip_summed = CHECKSUM_NONE;
83
84	/* Remove ipcomp header and decompress original payload */
85	ipch = (void *)skb->data;
86	nexthdr = ipch->nexthdr;
87
88	skb->transport_header = skb->network_header + sizeof(*ipch);
89	__skb_pull(skb, sizeof(*ipch));
90	err = ipcomp_decompress(x, skb);
91	if (err)
92	goto out;
93
94	err = nexthdr;
95
96	out:
97	return err;
98	}
99	EXPORT_SYMBOL_GPL(ipcomp_input);
100
101	static int ipcomp_compress(struct xfrm_state x, struct sk_buff skb)
102	{
103	struct ipcomp_data *ipcd = x->data;
104	const int plen = skb->len;
105	int dlen = IPCOMP_SCRATCH_SIZE;
106	u8 *start = skb->data;
107	const int cpu = get_cpu();
108	u8 scratch = per_cpu_ptr(ipcomp_scratches, cpu);
109	struct crypto_comp tfm = per_cpu_ptr(ipcd->tfms, cpu);
110	int err;
111
112	local_bh_disable();
113	err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
114	local_bh_enable();
115	if (err)
116	goto out;
117
118	if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) {
119	err = -EMSGSIZE;
120	goto out;
121	}
122
123	memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
124	put_cpu();
125
126	pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
127	return 0;
128
129	out:
130	put_cpu();
131	return err;
132	}
133
134	int ipcomp_output(struct xfrm_state x, struct sk_buff skb)
135	{
136	int err;
137	struct ip_comp_hdr *ipch;
138	struct ipcomp_data *ipcd = x->data;
139
140	if (skb->len < ipcd->threshold) {
141	/* Don't bother compressing */
142	goto out_ok;
143	}
144
145	if (skb_linearize_cow(skb))
146	goto out_ok;
147
148	err = ipcomp_compress(x, skb);
149
150	if (err) {
151	goto out_ok;
152	}
153
154	/* Install ipcomp header, convert into ipcomp datagram. */
155	ipch = ip_comp_hdr(skb);
156	ipch->nexthdr = *skb_mac_header(skb);
157	ipch->flags = 0;
158	ipch->cpi = htons((u16 )ntohl(x->id.spi));
159	*skb_mac_header(skb) = IPPROTO_COMP;
160	out_ok:
161	skb_push(skb, -skb_network_offset(skb));
162	return 0;
163	}
164	EXPORT_SYMBOL_GPL(ipcomp_output);
165
166	static void ipcomp_free_scratches(void)
167	{
168	int i;
169	void **scratches;
170
171	if (--ipcomp_scratch_users)
172	return;
173
174	scratches = ipcomp_scratches;
175	if (!scratches)
176	return;
177
178	for_each_possible_cpu(i)
179	vfree(*per_cpu_ptr(scratches, i));
180
181	free_percpu(scratches);
182	}
183
184	static void **ipcomp_alloc_scratches(void)
185	{
186	int i;
187	void **scratches;
188
189	if (ipcomp_scratch_users++)
190	return ipcomp_scratches;
191
192	scratches = alloc_percpu(void *);
193	if (!scratches)
194	return NULL;
195
196	ipcomp_scratches = scratches;
197
198	for_each_possible_cpu(i) {
199	void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
200	if (!scratch)
201	return NULL;
202	*per_cpu_ptr(scratches, i) = scratch;
203	}
204
205	return scratches;
206	}
207
208	static void ipcomp_free_tfms(struct crypto_comp **tfms)
209	{
210	struct ipcomp_tfms *pos;
211	int cpu;
212
213	list_for_each_entry(pos, &ipcomp_tfms_list, list) {
214	if (pos->tfms == tfms)
215	break;
216	}
217
218	BUG_TRAP(pos);
219
220	if (--pos->users)
221	return;
222
223	list_del(&pos->list);
224	kfree(pos);
225
226	if (!tfms)
227	return;
228
229	for_each_possible_cpu(cpu) {
230	struct crypto_comp tfm = per_cpu_ptr(tfms, cpu);
231	crypto_free_comp(tfm);
232	}
233	free_percpu(tfms);
234	}
235
236	static struct crypto_comp *ipcomp_alloc_tfms(const char alg_name)
237	{
238	struct ipcomp_tfms *pos;
239	struct crypto_comp **tfms;
240	int cpu;
241
242	/* This can be any valid CPU ID so we don't need locking. */
243	cpu = raw_smp_processor_id();
244
245	list_for_each_entry(pos, &ipcomp_tfms_list, list) {
246	struct crypto_comp *tfm;
247
248	tfms = pos->tfms;
249	tfm = *per_cpu_ptr(tfms, cpu);
250
251	if (!strcmp(crypto_comp_name(tfm), alg_name)) {
252	pos->users++;
253	return tfms;
254	}
255	}
256
257	pos = kmalloc(sizeof(*pos), GFP_KERNEL);
258	if (!pos)
259	return NULL;
260
261	pos->users = 1;
262	INIT_LIST_HEAD(&pos->list);
263	list_add(&pos->list, &ipcomp_tfms_list);
264
265	pos->tfms = tfms = alloc_percpu(struct crypto_comp *);
266	if (!tfms)
267	goto error;
268
269	for_each_possible_cpu(cpu) {
270	struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0,
271	CRYPTO_ALG_ASYNC);
272	if (IS_ERR(tfm))
273	goto error;
274	*per_cpu_ptr(tfms, cpu) = tfm;
275	}
276
277	return tfms;
278
279	error:
280	ipcomp_free_tfms(tfms);
281	return NULL;
282	}
283
284	static void ipcomp_free_data(struct ipcomp_data *ipcd)
285	{
286	if (ipcd->tfms)
287	ipcomp_free_tfms(ipcd->tfms);
288	ipcomp_free_scratches();
289	}
290
291	void ipcomp_destroy(struct xfrm_state *x)
292	{
293	struct ipcomp_data *ipcd = x->data;
294	if (!ipcd)
295	return;
296	xfrm_state_delete_tunnel(x);
297	mutex_lock(&ipcomp_resource_mutex);
298	ipcomp_free_data(ipcd);
299	mutex_unlock(&ipcomp_resource_mutex);
300	kfree(ipcd);
301	}
302	EXPORT_SYMBOL_GPL(ipcomp_destroy);
303
304	int ipcomp_init_state(struct xfrm_state *x)
305	{
306	int err;
307	struct ipcomp_data *ipcd;
308	struct xfrm_algo_desc *calg_desc;
309
310	err = -EINVAL;
311	if (!x->calg)
312	goto out;
313
314	if (x->encap)
315	goto out;
316
317	err = -ENOMEM;
318	ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
319	if (!ipcd)
320	goto out;
321
322	mutex_lock(&ipcomp_resource_mutex);
323	if (!ipcomp_alloc_scratches())
324	goto error;
325
326	ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name);
327	if (!ipcd->tfms)
328	goto error;
329	mutex_unlock(&ipcomp_resource_mutex);
330
331	calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
332	BUG_ON(!calg_desc);
333	ipcd->threshold = calg_desc->uinfo.comp.threshold;
334	x->data = ipcd;
335	err = 0;
336	out:
337	return err;
338
339	error:
340	ipcomp_free_data(ipcd);
341	mutex_unlock(&ipcomp_resource_mutex);
342	kfree(ipcd);
343	goto out;
344	}
345	EXPORT_SYMBOL_GPL(ipcomp_init_state);
346
347	MODULE_LICENSE("GPL");
348	MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173");
349	MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");