Commit | Line | Data |
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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; | |
747b6708 SD |
44 | u8 *scratch = *this_cpu_ptr(ipcomp_scratches); |
45 | struct crypto_comp *tfm = *this_cpu_ptr(ipcd->tfms); | |
6fccab67 | 46 | int err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen); |
7d7e5a60 | 47 | int len; |
6fccab67 HX |
48 | |
49 | if (err) | |
747b6708 | 50 | return err; |
6fccab67 | 51 | |
747b6708 SD |
52 | if (dlen < (plen + sizeof(struct ip_comp_hdr))) |
53 | return -EINVAL; | |
6fccab67 | 54 | |
7d7e5a60 HX |
55 | len = dlen - plen; |
56 | if (len > skb_tailroom(skb)) | |
57 | len = skb_tailroom(skb); | |
58 | ||
7d7e5a60 HX |
59 | __skb_put(skb, len); |
60 | ||
61 | len += plen; | |
62 | skb_copy_to_linear_data(skb, scratch, len); | |
63 | ||
64 | while ((scratch += len, dlen -= len) > 0) { | |
65 | skb_frag_t *frag; | |
804cf14e | 66 | struct page *page; |
7d7e5a60 | 67 | |
7d7e5a60 | 68 | if (WARN_ON(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS)) |
747b6708 | 69 | return -EMSGSIZE; |
7d7e5a60 HX |
70 | |
71 | frag = skb_shinfo(skb)->frags + skb_shinfo(skb)->nr_frags; | |
804cf14e | 72 | page = alloc_page(GFP_ATOMIC); |
7d7e5a60 | 73 | |
804cf14e | 74 | if (!page) |
747b6708 | 75 | return -ENOMEM; |
7d7e5a60 | 76 | |
804cf14e IC |
77 | __skb_frag_set_page(frag, page); |
78 | ||
7d7e5a60 HX |
79 | len = PAGE_SIZE; |
80 | if (dlen < len) | |
81 | len = dlen; | |
82 | ||
b54c9d5b | 83 | skb_frag_off_set(frag, 0); |
9e903e08 | 84 | skb_frag_size_set(frag, len); |
804cf14e IC |
85 | memcpy(skb_frag_address(frag), scratch, len); |
86 | ||
7d7e5a60 HX |
87 | skb->truesize += len; |
88 | skb->data_len += len; | |
89 | skb->len += len; | |
90 | ||
91 | skb_shinfo(skb)->nr_frags++; | |
92 | } | |
93 | ||
747b6708 | 94 | return 0; |
6fccab67 HX |
95 | } |
96 | ||
97 | int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb) | |
98 | { | |
99 | int nexthdr; | |
100 | int err = -ENOMEM; | |
101 | struct ip_comp_hdr *ipch; | |
102 | ||
103 | if (skb_linearize_cow(skb)) | |
104 | goto out; | |
105 | ||
106 | skb->ip_summed = CHECKSUM_NONE; | |
107 | ||
108 | /* Remove ipcomp header and decompress original payload */ | |
109 | ipch = (void *)skb->data; | |
110 | nexthdr = ipch->nexthdr; | |
111 | ||
112 | skb->transport_header = skb->network_header + sizeof(*ipch); | |
113 | __skb_pull(skb, sizeof(*ipch)); | |
114 | err = ipcomp_decompress(x, skb); | |
115 | if (err) | |
116 | goto out; | |
117 | ||
118 | err = nexthdr; | |
119 | ||
120 | out: | |
121 | return err; | |
122 | } | |
123 | EXPORT_SYMBOL_GPL(ipcomp_input); | |
124 | ||
125 | static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb) | |
126 | { | |
127 | struct ipcomp_data *ipcd = x->data; | |
128 | const int plen = skb->len; | |
129 | int dlen = IPCOMP_SCRATCH_SIZE; | |
130 | u8 *start = skb->data; | |
12e35946 MK |
131 | struct crypto_comp *tfm; |
132 | u8 *scratch; | |
6fccab67 HX |
133 | int err; |
134 | ||
135 | local_bh_disable(); | |
12e35946 MK |
136 | scratch = *this_cpu_ptr(ipcomp_scratches); |
137 | tfm = *this_cpu_ptr(ipcd->tfms); | |
6fccab67 | 138 | err = crypto_comp_compress(tfm, start, plen, scratch, &dlen); |
6fccab67 HX |
139 | if (err) |
140 | goto out; | |
141 | ||
142 | if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) { | |
143 | err = -EMSGSIZE; | |
144 | goto out; | |
145 | } | |
146 | ||
147 | memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen); | |
12e35946 | 148 | local_bh_enable(); |
6fccab67 HX |
149 | |
150 | pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr)); | |
151 | return 0; | |
152 | ||
153 | out: | |
12e35946 | 154 | local_bh_enable(); |
6fccab67 HX |
155 | return err; |
156 | } | |
157 | ||
158 | int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb) | |
159 | { | |
160 | int err; | |
161 | struct ip_comp_hdr *ipch; | |
162 | struct ipcomp_data *ipcd = x->data; | |
163 | ||
164 | if (skb->len < ipcd->threshold) { | |
165 | /* Don't bother compressing */ | |
166 | goto out_ok; | |
167 | } | |
168 | ||
169 | if (skb_linearize_cow(skb)) | |
170 | goto out_ok; | |
171 | ||
172 | err = ipcomp_compress(x, skb); | |
173 | ||
174 | if (err) { | |
175 | goto out_ok; | |
176 | } | |
177 | ||
178 | /* Install ipcomp header, convert into ipcomp datagram. */ | |
179 | ipch = ip_comp_hdr(skb); | |
180 | ipch->nexthdr = *skb_mac_header(skb); | |
181 | ipch->flags = 0; | |
182 | ipch->cpi = htons((u16 )ntohl(x->id.spi)); | |
183 | *skb_mac_header(skb) = IPPROTO_COMP; | |
184 | out_ok: | |
185 | skb_push(skb, -skb_network_offset(skb)); | |
186 | return 0; | |
187 | } | |
188 | EXPORT_SYMBOL_GPL(ipcomp_output); | |
189 | ||
190 | static void ipcomp_free_scratches(void) | |
191 | { | |
192 | int i; | |
7d720c3e | 193 | void * __percpu *scratches; |
6fccab67 HX |
194 | |
195 | if (--ipcomp_scratch_users) | |
196 | return; | |
197 | ||
198 | scratches = ipcomp_scratches; | |
199 | if (!scratches) | |
200 | return; | |
201 | ||
202 | for_each_possible_cpu(i) | |
203 | vfree(*per_cpu_ptr(scratches, i)); | |
204 | ||
205 | free_percpu(scratches); | |
8a04d2fc | 206 | ipcomp_scratches = NULL; |
6fccab67 HX |
207 | } |
208 | ||
7d720c3e | 209 | static void * __percpu *ipcomp_alloc_scratches(void) |
6fccab67 | 210 | { |
7d720c3e | 211 | void * __percpu *scratches; |
5cf4eb54 | 212 | int i; |
6fccab67 HX |
213 | |
214 | if (ipcomp_scratch_users++) | |
215 | return ipcomp_scratches; | |
216 | ||
217 | scratches = alloc_percpu(void *); | |
218 | if (!scratches) | |
219 | return NULL; | |
220 | ||
221 | ipcomp_scratches = scratches; | |
222 | ||
223 | for_each_possible_cpu(i) { | |
5cf4eb54 ED |
224 | void *scratch; |
225 | ||
226 | scratch = vmalloc_node(IPCOMP_SCRATCH_SIZE, cpu_to_node(i)); | |
6fccab67 HX |
227 | if (!scratch) |
228 | return NULL; | |
229 | *per_cpu_ptr(scratches, i) = scratch; | |
230 | } | |
231 | ||
232 | return scratches; | |
233 | } | |
234 | ||
7d720c3e | 235 | static void ipcomp_free_tfms(struct crypto_comp * __percpu *tfms) |
6fccab67 HX |
236 | { |
237 | struct ipcomp_tfms *pos; | |
238 | int cpu; | |
239 | ||
240 | list_for_each_entry(pos, &ipcomp_tfms_list, list) { | |
241 | if (pos->tfms == tfms) | |
242 | break; | |
243 | } | |
244 | ||
480e93e1 | 245 | WARN_ON(list_entry_is_head(pos, &ipcomp_tfms_list, list)); |
6fccab67 HX |
246 | |
247 | if (--pos->users) | |
248 | return; | |
249 | ||
250 | list_del(&pos->list); | |
251 | kfree(pos); | |
252 | ||
253 | if (!tfms) | |
254 | return; | |
255 | ||
256 | for_each_possible_cpu(cpu) { | |
257 | struct crypto_comp *tfm = *per_cpu_ptr(tfms, cpu); | |
258 | crypto_free_comp(tfm); | |
259 | } | |
260 | free_percpu(tfms); | |
261 | } | |
262 | ||
7d720c3e | 263 | static struct crypto_comp * __percpu *ipcomp_alloc_tfms(const char *alg_name) |
6fccab67 HX |
264 | { |
265 | struct ipcomp_tfms *pos; | |
7d720c3e | 266 | struct crypto_comp * __percpu *tfms; |
6fccab67 HX |
267 | int cpu; |
268 | ||
6fccab67 HX |
269 | |
270 | list_for_each_entry(pos, &ipcomp_tfms_list, list) { | |
271 | struct crypto_comp *tfm; | |
272 | ||
f7c83bcb | 273 | /* This can be any valid CPU ID so we don't need locking. */ |
0dcd7876 | 274 | tfm = this_cpu_read(*pos->tfms); |
6fccab67 HX |
275 | |
276 | if (!strcmp(crypto_comp_name(tfm), alg_name)) { | |
277 | pos->users++; | |
f7c83bcb | 278 | return pos->tfms; |
6fccab67 HX |
279 | } |
280 | } | |
281 | ||
282 | pos = kmalloc(sizeof(*pos), GFP_KERNEL); | |
283 | if (!pos) | |
284 | return NULL; | |
285 | ||
286 | pos->users = 1; | |
287 | INIT_LIST_HEAD(&pos->list); | |
288 | list_add(&pos->list, &ipcomp_tfms_list); | |
289 | ||
290 | pos->tfms = tfms = alloc_percpu(struct crypto_comp *); | |
291 | if (!tfms) | |
292 | goto error; | |
293 | ||
294 | for_each_possible_cpu(cpu) { | |
295 | struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0, | |
296 | CRYPTO_ALG_ASYNC); | |
297 | if (IS_ERR(tfm)) | |
298 | goto error; | |
299 | *per_cpu_ptr(tfms, cpu) = tfm; | |
300 | } | |
301 | ||
302 | return tfms; | |
303 | ||
304 | error: | |
305 | ipcomp_free_tfms(tfms); | |
306 | return NULL; | |
307 | } | |
308 | ||
309 | static void ipcomp_free_data(struct ipcomp_data *ipcd) | |
310 | { | |
311 | if (ipcd->tfms) | |
312 | ipcomp_free_tfms(ipcd->tfms); | |
313 | ipcomp_free_scratches(); | |
314 | } | |
315 | ||
316 | void ipcomp_destroy(struct xfrm_state *x) | |
317 | { | |
318 | struct ipcomp_data *ipcd = x->data; | |
319 | if (!ipcd) | |
320 | return; | |
321 | xfrm_state_delete_tunnel(x); | |
322 | mutex_lock(&ipcomp_resource_mutex); | |
323 | ipcomp_free_data(ipcd); | |
324 | mutex_unlock(&ipcomp_resource_mutex); | |
325 | kfree(ipcd); | |
326 | } | |
327 | EXPORT_SYMBOL_GPL(ipcomp_destroy); | |
328 | ||
6ee55320 | 329 | int ipcomp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack) |
6fccab67 HX |
330 | { |
331 | int err; | |
332 | struct ipcomp_data *ipcd; | |
333 | struct xfrm_algo_desc *calg_desc; | |
334 | ||
335 | err = -EINVAL; | |
6ee55320 SD |
336 | if (!x->calg) { |
337 | NL_SET_ERR_MSG(extack, "Missing required compression algorithm"); | |
6fccab67 | 338 | goto out; |
6ee55320 | 339 | } |
6fccab67 | 340 | |
6ee55320 SD |
341 | if (x->encap) { |
342 | NL_SET_ERR_MSG(extack, "IPComp is not compatible with encapsulation"); | |
6fccab67 | 343 | goto out; |
6ee55320 | 344 | } |
6fccab67 HX |
345 | |
346 | err = -ENOMEM; | |
347 | ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL); | |
348 | if (!ipcd) | |
349 | goto out; | |
350 | ||
351 | mutex_lock(&ipcomp_resource_mutex); | |
352 | if (!ipcomp_alloc_scratches()) | |
353 | goto error; | |
354 | ||
355 | ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name); | |
356 | if (!ipcd->tfms) | |
357 | goto error; | |
358 | mutex_unlock(&ipcomp_resource_mutex); | |
359 | ||
360 | calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0); | |
361 | BUG_ON(!calg_desc); | |
362 | ipcd->threshold = calg_desc->uinfo.comp.threshold; | |
363 | x->data = ipcd; | |
364 | err = 0; | |
365 | out: | |
366 | return err; | |
367 | ||
368 | error: | |
369 | ipcomp_free_data(ipcd); | |
370 | mutex_unlock(&ipcomp_resource_mutex); | |
371 | kfree(ipcd); | |
372 | goto out; | |
373 | } | |
374 | EXPORT_SYMBOL_GPL(ipcomp_init_state); | |
375 | ||
376 | MODULE_LICENSE("GPL"); | |
377 | MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173"); | |
378 | MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>"); |