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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 | |
78 | err = -ENOMEM; | |
804cf14e | 79 | if (!page) |
7d7e5a60 HX |
80 | goto out; |
81 | ||
804cf14e IC |
82 | __skb_frag_set_page(frag, page); |
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); |
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; |
141 | u8 *scratch; | |
6fccab67 HX |
142 | int err; |
143 | ||
144 | local_bh_disable(); | |
12e35946 MK |
145 | scratch = *this_cpu_ptr(ipcomp_scratches); |
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 | { |
273 | struct ipcomp_tfms *pos; | |
7d720c3e | 274 | struct crypto_comp * __percpu *tfms; |
6fccab67 HX |
275 | int cpu; |
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>"); |