1 | // SPDX-License-Identifier: GPL-2.0-or-later |
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 | * |
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> |
20 | #include <linux/slab.h> |
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; |
29 | struct crypto_comp * __percpu *tfms; |
30 | int users; |
31 | }; |
32 | |
33 | static DEFINE_MUTEX(ipcomp_resource_mutex); |
34 | static void * __percpu *ipcomp_scratches; |
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 | u8 *scratch = *this_cpu_ptr(ipcomp_scratches); |
45 | struct crypto_comp *tfm = *this_cpu_ptr(ipcd->tfms); |
46 | int err = crypto_comp_decompress(tfm, src: start, slen: plen, dst: scratch, dlen: &dlen); |
47 | int len; |
48 | |
49 | if (err) |
50 | return err; |
51 | |
52 | if (dlen < (plen + sizeof(struct ip_comp_hdr))) |
53 | return -EINVAL; |
54 | |
55 | len = dlen - plen; |
56 | if (len > skb_tailroom(skb)) |
57 | len = skb_tailroom(skb); |
58 | |
59 | __skb_put(skb, len); |
60 | |
61 | len += plen; |
62 | skb_copy_to_linear_data(skb, from: scratch, len); |
63 | |
64 | while ((scratch += len, dlen -= len) > 0) { |
65 | skb_frag_t *frag; |
66 | struct page *page; |
67 | |
68 | if (WARN_ON(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS)) |
69 | return -EMSGSIZE; |
70 | |
71 | frag = skb_shinfo(skb)->frags + skb_shinfo(skb)->nr_frags; |
72 | page = alloc_page(GFP_ATOMIC); |
73 | |
74 | if (!page) |
75 | return -ENOMEM; |
76 | |
77 | len = PAGE_SIZE; |
78 | if (dlen < len) |
79 | len = dlen; |
80 | |
81 | skb_frag_fill_page_desc(frag, page, off: 0, size: len); |
82 | memcpy(skb_frag_address(frag), scratch, len); |
83 | |
84 | skb->truesize += len; |
85 | skb->data_len += len; |
86 | skb->len += len; |
87 | |
88 | skb_shinfo(skb)->nr_frags++; |
89 | } |
90 | |
91 | return 0; |
92 | } |
93 | |
94 | int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb) |
95 | { |
96 | int nexthdr; |
97 | int err = -ENOMEM; |
98 | struct ip_comp_hdr *ipch; |
99 | |
100 | if (skb_linearize_cow(skb)) |
101 | goto out; |
102 | |
103 | skb->ip_summed = CHECKSUM_NONE; |
104 | |
105 | /* Remove ipcomp header and decompress original payload */ |
106 | ipch = (void *)skb->data; |
107 | nexthdr = ipch->nexthdr; |
108 | |
109 | skb->transport_header = skb->network_header + sizeof(*ipch); |
110 | __skb_pull(skb, len: sizeof(*ipch)); |
111 | err = ipcomp_decompress(x, skb); |
112 | if (err) |
113 | goto out; |
114 | |
115 | err = nexthdr; |
116 | |
117 | out: |
118 | return err; |
119 | } |
120 | EXPORT_SYMBOL_GPL(ipcomp_input); |
121 | |
122 | static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb) |
123 | { |
124 | struct ipcomp_data *ipcd = x->data; |
125 | const int plen = skb->len; |
126 | int dlen = IPCOMP_SCRATCH_SIZE; |
127 | u8 *start = skb->data; |
128 | struct crypto_comp *tfm; |
129 | u8 *scratch; |
130 | int err; |
131 | |
132 | local_bh_disable(); |
133 | scratch = *this_cpu_ptr(ipcomp_scratches); |
134 | tfm = *this_cpu_ptr(ipcd->tfms); |
135 | err = crypto_comp_compress(tfm, src: start, slen: plen, dst: scratch, dlen: &dlen); |
136 | if (err) |
137 | goto out; |
138 | |
139 | if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) { |
140 | err = -EMSGSIZE; |
141 | goto out; |
142 | } |
143 | |
144 | memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen); |
145 | local_bh_enable(); |
146 | |
147 | pskb_trim(skb, len: dlen + sizeof(struct ip_comp_hdr)); |
148 | return 0; |
149 | |
150 | out: |
151 | local_bh_enable(); |
152 | return err; |
153 | } |
154 | |
155 | int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb) |
156 | { |
157 | int err; |
158 | struct ip_comp_hdr *ipch; |
159 | struct ipcomp_data *ipcd = x->data; |
160 | |
161 | if (skb->len < ipcd->threshold) { |
162 | /* Don't bother compressing */ |
163 | goto out_ok; |
164 | } |
165 | |
166 | if (skb_linearize_cow(skb)) |
167 | goto out_ok; |
168 | |
169 | err = ipcomp_compress(x, skb); |
170 | |
171 | if (err) { |
172 | goto out_ok; |
173 | } |
174 | |
175 | /* Install ipcomp header, convert into ipcomp datagram. */ |
176 | ipch = ip_comp_hdr(skb); |
177 | ipch->nexthdr = *skb_mac_header(skb); |
178 | ipch->flags = 0; |
179 | ipch->cpi = htons((u16 )ntohl(x->id.spi)); |
180 | *skb_mac_header(skb) = IPPROTO_COMP; |
181 | out_ok: |
182 | skb_push(skb, len: -skb_network_offset(skb)); |
183 | return 0; |
184 | } |
185 | EXPORT_SYMBOL_GPL(ipcomp_output); |
186 | |
187 | static void ipcomp_free_scratches(void) |
188 | { |
189 | int i; |
190 | void * __percpu *scratches; |
191 | |
192 | if (--ipcomp_scratch_users) |
193 | return; |
194 | |
195 | scratches = ipcomp_scratches; |
196 | if (!scratches) |
197 | return; |
198 | |
199 | for_each_possible_cpu(i) |
200 | vfree(addr: *per_cpu_ptr(scratches, i)); |
201 | |
202 | free_percpu(pdata: scratches); |
203 | ipcomp_scratches = NULL; |
204 | } |
205 | |
206 | static void * __percpu *ipcomp_alloc_scratches(void) |
207 | { |
208 | void * __percpu *scratches; |
209 | int i; |
210 | |
211 | if (ipcomp_scratch_users++) |
212 | return ipcomp_scratches; |
213 | |
214 | scratches = alloc_percpu(void *); |
215 | if (!scratches) |
216 | return NULL; |
217 | |
218 | ipcomp_scratches = scratches; |
219 | |
220 | for_each_possible_cpu(i) { |
221 | void *scratch; |
222 | |
223 | scratch = vmalloc_node(IPCOMP_SCRATCH_SIZE, cpu_to_node(cpu: i)); |
224 | if (!scratch) |
225 | return NULL; |
226 | *per_cpu_ptr(scratches, i) = scratch; |
227 | } |
228 | |
229 | return scratches; |
230 | } |
231 | |
232 | static void ipcomp_free_tfms(struct crypto_comp * __percpu *tfms) |
233 | { |
234 | struct ipcomp_tfms *pos; |
235 | int cpu; |
236 | |
237 | list_for_each_entry(pos, &ipcomp_tfms_list, list) { |
238 | if (pos->tfms == tfms) |
239 | break; |
240 | } |
241 | |
242 | WARN_ON(list_entry_is_head(pos, &ipcomp_tfms_list, list)); |
243 | |
244 | if (--pos->users) |
245 | return; |
246 | |
247 | list_del(entry: &pos->list); |
248 | kfree(objp: pos); |
249 | |
250 | if (!tfms) |
251 | return; |
252 | |
253 | for_each_possible_cpu(cpu) { |
254 | struct crypto_comp *tfm = *per_cpu_ptr(tfms, cpu); |
255 | crypto_free_comp(tfm); |
256 | } |
257 | free_percpu(pdata: tfms); |
258 | } |
259 | |
260 | static struct crypto_comp * __percpu *ipcomp_alloc_tfms(const char *alg_name) |
261 | { |
262 | struct ipcomp_tfms *pos; |
263 | struct crypto_comp * __percpu *tfms; |
264 | int cpu; |
265 | |
266 | |
267 | list_for_each_entry(pos, &ipcomp_tfms_list, list) { |
268 | struct crypto_comp *tfm; |
269 | |
270 | /* This can be any valid CPU ID so we don't need locking. */ |
271 | tfm = this_cpu_read(*pos->tfms); |
272 | |
273 | if (!strcmp(crypto_comp_name(tfm), alg_name)) { |
274 | pos->users++; |
275 | return pos->tfms; |
276 | } |
277 | } |
278 | |
279 | pos = kmalloc(size: sizeof(*pos), GFP_KERNEL); |
280 | if (!pos) |
281 | return NULL; |
282 | |
283 | pos->users = 1; |
284 | INIT_LIST_HEAD(list: &pos->list); |
285 | list_add(new: &pos->list, head: &ipcomp_tfms_list); |
286 | |
287 | pos->tfms = tfms = alloc_percpu(struct crypto_comp *); |
288 | if (!tfms) |
289 | goto error; |
290 | |
291 | for_each_possible_cpu(cpu) { |
292 | struct crypto_comp *tfm = crypto_alloc_comp(alg_name, type: 0, |
293 | CRYPTO_ALG_ASYNC); |
294 | if (IS_ERR(ptr: tfm)) |
295 | goto error; |
296 | *per_cpu_ptr(tfms, cpu) = tfm; |
297 | } |
298 | |
299 | return tfms; |
300 | |
301 | error: |
302 | ipcomp_free_tfms(tfms); |
303 | return NULL; |
304 | } |
305 | |
306 | static void ipcomp_free_data(struct ipcomp_data *ipcd) |
307 | { |
308 | if (ipcd->tfms) |
309 | ipcomp_free_tfms(tfms: ipcd->tfms); |
310 | ipcomp_free_scratches(); |
311 | } |
312 | |
313 | void ipcomp_destroy(struct xfrm_state *x) |
314 | { |
315 | struct ipcomp_data *ipcd = x->data; |
316 | if (!ipcd) |
317 | return; |
318 | xfrm_state_delete_tunnel(x); |
319 | mutex_lock(&ipcomp_resource_mutex); |
320 | ipcomp_free_data(ipcd); |
321 | mutex_unlock(lock: &ipcomp_resource_mutex); |
322 | kfree(objp: ipcd); |
323 | } |
324 | EXPORT_SYMBOL_GPL(ipcomp_destroy); |
325 | |
326 | int ipcomp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack) |
327 | { |
328 | int err; |
329 | struct ipcomp_data *ipcd; |
330 | struct xfrm_algo_desc *calg_desc; |
331 | |
332 | err = -EINVAL; |
333 | if (!x->calg) { |
334 | NL_SET_ERR_MSG(extack, "Missing required compression algorithm" ); |
335 | goto out; |
336 | } |
337 | |
338 | if (x->encap) { |
339 | NL_SET_ERR_MSG(extack, "IPComp is not compatible with encapsulation" ); |
340 | goto out; |
341 | } |
342 | |
343 | err = -ENOMEM; |
344 | ipcd = kzalloc(size: sizeof(*ipcd), GFP_KERNEL); |
345 | if (!ipcd) |
346 | goto out; |
347 | |
348 | mutex_lock(&ipcomp_resource_mutex); |
349 | if (!ipcomp_alloc_scratches()) |
350 | goto error; |
351 | |
352 | ipcd->tfms = ipcomp_alloc_tfms(alg_name: x->calg->alg_name); |
353 | if (!ipcd->tfms) |
354 | goto error; |
355 | mutex_unlock(lock: &ipcomp_resource_mutex); |
356 | |
357 | calg_desc = xfrm_calg_get_byname(name: x->calg->alg_name, probe: 0); |
358 | BUG_ON(!calg_desc); |
359 | ipcd->threshold = calg_desc->uinfo.comp.threshold; |
360 | x->data = ipcd; |
361 | err = 0; |
362 | out: |
363 | return err; |
364 | |
365 | error: |
366 | ipcomp_free_data(ipcd); |
367 | mutex_unlock(lock: &ipcomp_resource_mutex); |
368 | kfree(objp: ipcd); |
369 | goto out; |
370 | } |
371 | EXPORT_SYMBOL_GPL(ipcomp_init_state); |
372 | |
373 | MODULE_LICENSE("GPL" ); |
374 | MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173" ); |
375 | MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>" ); |
376 | |