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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>"); |