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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> | |
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>"); |