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064af421 | 1 | /* |
30f07f1a | 2 | * Copyright (c) 2008, 2009, 2010 Nicira Networks. |
064af421 | 3 | * |
a14bc59f BP |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
5 | * you may not use this file except in compliance with the License. | |
6 | * You may obtain a copy of the License at: | |
064af421 | 7 | * |
a14bc59f BP |
8 | * http://www.apache.org/licenses/LICENSE-2.0 |
9 | * | |
10 | * Unless required by applicable law or agreed to in writing, software | |
11 | * distributed under the License is distributed on an "AS IS" BASIS, | |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
13 | * See the License for the specific language governing permissions and | |
14 | * limitations under the License. | |
064af421 BP |
15 | */ |
16 | ||
17 | #include <config.h> | |
18 | #include "ofpbuf.h" | |
19 | #include <assert.h> | |
20 | #include <stdlib.h> | |
21 | #include <string.h> | |
0ab8e15f | 22 | #include "dynamic-string.h" |
064af421 BP |
23 | #include "util.h" |
24 | ||
31ac1e59 BP |
25 | static void |
26 | ofpbuf_use__(struct ofpbuf *b, void *base, size_t allocated, | |
27 | enum ofpbuf_source source) | |
064af421 BP |
28 | { |
29 | b->base = b->data = base; | |
30 | b->allocated = allocated; | |
31ac1e59 | 31 | b->source = source; |
064af421 BP |
32 | b->size = 0; |
33 | b->l2 = b->l3 = b->l4 = b->l7 = NULL; | |
b3907fbc | 34 | list_poison(&b->list_node); |
d45e9c65 | 35 | b->private_p = NULL; |
064af421 BP |
36 | } |
37 | ||
31ac1e59 BP |
38 | /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of |
39 | * memory starting at 'base'. 'base' should be the first byte of a region | |
40 | * obtained from malloc(). It will be freed (with free()) if 'b' is resized or | |
41 | * freed. */ | |
42 | void | |
43 | ofpbuf_use(struct ofpbuf *b, void *base, size_t allocated) | |
44 | { | |
45 | ofpbuf_use__(b, base, allocated, OFPBUF_MALLOC); | |
46 | } | |
47 | ||
48 | /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of | |
49 | * memory starting at 'base'. 'base' should point to a buffer on the stack. | |
50 | * If 'b' is resized, new memory will be allocated with malloc() and 'base' | |
51 | * will not be freed. This is useful when a small stack-allocated buffer is | |
52 | * normally appropriate but sometimes it must be expanded. | |
53 | * | |
54 | * 'base' should be appropriately aligned. Using an array of uint32_t or | |
55 | * uint64_t for the buffer is a reasonable way to ensure appropriate alignment | |
56 | * for 32- or 64-bit data. | |
57 | * | |
58 | * (Nothing actually relies on 'base' being allocated on the stack. It could | |
59 | * be static or malloc()'d memory. But stack space is the most common use | |
60 | * case.) */ | |
61 | void | |
62 | ofpbuf_use_stack(struct ofpbuf *b, void *base, size_t allocated) | |
63 | { | |
64 | ofpbuf_use__(b, base, allocated, OFPBUF_STACK); | |
65 | } | |
66 | ||
0bc9407d BP |
67 | /* Initializes 'b' as an ofpbuf whose data starts at 'data' and continues for |
68 | * 'size' bytes. This is appropriate for an ofpbuf that will be used to | |
69 | * inspect existing data, without moving it around or reallocating it, and | |
31ac1e59 BP |
70 | * generally without modifying it at all. |
71 | * | |
72 | * An ofpbuf operation that requires reallocating data will assert-fail if this | |
73 | * function was used to initialize it. */ | |
0bc9407d BP |
74 | void |
75 | ofpbuf_use_const(struct ofpbuf *b, const void *data, size_t size) | |
76 | { | |
31ac1e59 | 77 | ofpbuf_use__(b, (void *) data, size, OFPBUF_CONST); |
0bc9407d BP |
78 | b->size = size; |
79 | } | |
80 | ||
064af421 BP |
81 | /* Initializes 'b' as an empty ofpbuf with an initial capacity of 'size' |
82 | * bytes. */ | |
83 | void | |
84 | ofpbuf_init(struct ofpbuf *b, size_t size) | |
85 | { | |
86 | ofpbuf_use(b, size ? xmalloc(size) : NULL, size); | |
87 | } | |
88 | ||
89 | /* Frees memory that 'b' points to. */ | |
90 | void | |
d295e8e9 | 91 | ofpbuf_uninit(struct ofpbuf *b) |
064af421 | 92 | { |
31ac1e59 | 93 | if (b && b->source == OFPBUF_MALLOC) { |
064af421 BP |
94 | free(b->base); |
95 | } | |
96 | } | |
97 | ||
98 | /* Frees memory that 'b' points to and allocates a new ofpbuf */ | |
99 | void | |
100 | ofpbuf_reinit(struct ofpbuf *b, size_t size) | |
101 | { | |
102 | ofpbuf_uninit(b); | |
103 | ofpbuf_init(b, size); | |
104 | } | |
105 | ||
106 | /* Creates and returns a new ofpbuf with an initial capacity of 'size' | |
107 | * bytes. */ | |
108 | struct ofpbuf * | |
109 | ofpbuf_new(size_t size) | |
110 | { | |
111 | struct ofpbuf *b = xmalloc(sizeof *b); | |
112 | ofpbuf_init(b, size); | |
113 | return b; | |
114 | } | |
115 | ||
68efcbec BP |
116 | /* Creates and returns a new ofpbuf with an initial capacity of 'size + |
117 | * headroom' bytes, reserving the first 'headroom' bytes as headroom. */ | |
118 | struct ofpbuf * | |
119 | ofpbuf_new_with_headroom(size_t size, size_t headroom) | |
120 | { | |
121 | struct ofpbuf *b = ofpbuf_new(size + headroom); | |
122 | ofpbuf_reserve(b, headroom); | |
123 | return b; | |
124 | } | |
125 | ||
a46c577a BP |
126 | /* Creates and returns a new ofpbuf that initially contains a copy of the |
127 | * 'buffer->size' bytes of data starting at 'buffer->data' with no headroom or | |
128 | * tailroom. */ | |
064af421 BP |
129 | struct ofpbuf * |
130 | ofpbuf_clone(const struct ofpbuf *buffer) | |
131 | { | |
132 | return ofpbuf_clone_data(buffer->data, buffer->size); | |
133 | } | |
134 | ||
68efcbec BP |
135 | /* Creates and returns a new ofpbuf whose data are copied from 'buffer'. The |
136 | * returned ofpbuf will additionally have 'headroom' bytes of headroom. */ | |
137 | struct ofpbuf * | |
138 | ofpbuf_clone_with_headroom(const struct ofpbuf *buffer, size_t headroom) | |
139 | { | |
a46c577a BP |
140 | return ofpbuf_clone_data_with_headroom(buffer->data, buffer->size, |
141 | headroom); | |
68efcbec BP |
142 | } |
143 | ||
a46c577a BP |
144 | /* Creates and returns a new ofpbuf that initially contains a copy of the |
145 | * 'size' bytes of data starting at 'data' with no headroom or tailroom. */ | |
064af421 BP |
146 | struct ofpbuf * |
147 | ofpbuf_clone_data(const void *data, size_t size) | |
148 | { | |
a46c577a BP |
149 | return ofpbuf_clone_data_with_headroom(data, size, 0); |
150 | } | |
151 | ||
152 | /* Creates and returns a new ofpbuf that initially contains 'headroom' bytes of | |
153 | * headroom followed by a copy of the 'size' bytes of data starting at | |
154 | * 'data'. */ | |
155 | struct ofpbuf * | |
156 | ofpbuf_clone_data_with_headroom(const void *data, size_t size, size_t headroom) | |
157 | { | |
158 | struct ofpbuf *b = ofpbuf_new_with_headroom(size, headroom); | |
064af421 BP |
159 | ofpbuf_put(b, data, size); |
160 | return b; | |
161 | } | |
162 | ||
163 | /* Frees memory that 'b' points to, as well as 'b' itself. */ | |
164 | void | |
d295e8e9 | 165 | ofpbuf_delete(struct ofpbuf *b) |
064af421 BP |
166 | { |
167 | if (b) { | |
168 | ofpbuf_uninit(b); | |
169 | free(b); | |
170 | } | |
171 | } | |
172 | ||
173 | /* Returns the number of bytes of headroom in 'b', that is, the number of bytes | |
174 | * of unused space in ofpbuf 'b' before the data that is in use. (Most | |
175 | * commonly, the data in a ofpbuf is at its beginning, and thus the ofpbuf's | |
176 | * headroom is 0.) */ | |
177 | size_t | |
5019f688 | 178 | ofpbuf_headroom(const struct ofpbuf *b) |
064af421 BP |
179 | { |
180 | return (char*)b->data - (char*)b->base; | |
181 | } | |
182 | ||
183 | /* Returns the number of bytes that may be appended to the tail end of ofpbuf | |
184 | * 'b' before the ofpbuf must be reallocated. */ | |
185 | size_t | |
5019f688 | 186 | ofpbuf_tailroom(const struct ofpbuf *b) |
064af421 BP |
187 | { |
188 | return (char*)ofpbuf_end(b) - (char*)ofpbuf_tail(b); | |
189 | } | |
190 | ||
1f5cbaa3 | 191 | static void |
0dce369b BP |
192 | ofpbuf_copy__(struct ofpbuf *b, uint8_t *new_base, |
193 | size_t new_headroom, size_t new_tailroom) | |
064af421 | 194 | { |
0dce369b BP |
195 | const uint8_t *old_base = b->base; |
196 | size_t old_headroom = ofpbuf_headroom(b); | |
197 | size_t old_tailroom = ofpbuf_tailroom(b); | |
198 | size_t copy_headroom = MIN(old_headroom, new_headroom); | |
199 | size_t copy_tailroom = MIN(old_tailroom, new_tailroom); | |
200 | ||
201 | memcpy(&new_base[new_headroom - copy_headroom], | |
202 | &old_base[old_headroom - copy_headroom], | |
203 | copy_headroom + b->size + copy_tailroom); | |
064af421 BP |
204 | } |
205 | ||
0dce369b BP |
206 | /* Reallocates 'b' so that it has exactly 'new_headroom' and 'new_tailroom' |
207 | * bytes of headroom and tailroom, respectively. */ | |
1f5cbaa3 | 208 | static void |
0dce369b | 209 | ofpbuf_resize__(struct ofpbuf *b, size_t new_headroom, size_t new_tailroom) |
1f5cbaa3 | 210 | { |
0dce369b | 211 | void *new_base, *new_data; |
31ac1e59 | 212 | size_t new_allocated; |
31ac1e59 | 213 | |
0dce369b | 214 | new_allocated = new_headroom + b->size + new_tailroom; |
31ac1e59 BP |
215 | |
216 | switch (b->source) { | |
217 | case OFPBUF_MALLOC: | |
0dce369b BP |
218 | if (new_headroom == ofpbuf_headroom(b)) { |
219 | new_base = xrealloc(b->base, new_allocated); | |
220 | } else { | |
221 | new_base = xmalloc(new_allocated); | |
222 | ofpbuf_copy__(b, new_base, new_headroom, new_tailroom); | |
223 | free(b->base); | |
224 | } | |
31ac1e59 BP |
225 | break; |
226 | ||
227 | case OFPBUF_STACK: | |
228 | new_base = xmalloc(new_allocated); | |
0dce369b | 229 | ofpbuf_copy__(b, new_base, new_headroom, new_tailroom); |
31ac1e59 BP |
230 | b->source = OFPBUF_MALLOC; |
231 | break; | |
232 | ||
233 | case OFPBUF_CONST: | |
234 | NOT_REACHED(); | |
235 | ||
236 | default: | |
237 | NOT_REACHED(); | |
238 | } | |
239 | ||
240 | b->allocated = new_allocated; | |
0dce369b BP |
241 | b->base = new_base; |
242 | ||
243 | new_data = (char *) new_base + new_headroom; | |
244 | if (b->data != new_data) { | |
245 | uintptr_t data_delta = (char *) new_data - (char *) b->data; | |
246 | b->data = new_data; | |
247 | if (b->l2) { | |
248 | b->l2 = (char *) b->l2 + data_delta; | |
249 | } | |
250 | if (b->l3) { | |
251 | b->l3 = (char *) b->l3 + data_delta; | |
252 | } | |
253 | if (b->l4) { | |
254 | b->l4 = (char *) b->l4 + data_delta; | |
255 | } | |
256 | if (b->l7) { | |
257 | b->l7 = (char *) b->l7 + data_delta; | |
258 | } | |
259 | } | |
1f5cbaa3 BP |
260 | } |
261 | ||
262 | /* Ensures that 'b' has room for at least 'size' bytes at its tail end, | |
263 | * reallocating and copying its data if necessary. Its headroom, if any, is | |
264 | * preserved. */ | |
265 | void | |
d295e8e9 | 266 | ofpbuf_prealloc_tailroom(struct ofpbuf *b, size_t size) |
1f5cbaa3 BP |
267 | { |
268 | if (size > ofpbuf_tailroom(b)) { | |
0dce369b | 269 | ofpbuf_resize__(b, ofpbuf_headroom(b), MAX(size, 64)); |
1f5cbaa3 BP |
270 | } |
271 | } | |
272 | ||
0dce369b BP |
273 | /* Ensures that 'b' has room for at least 'size' bytes at its head, |
274 | * reallocating and copying its data if necessary. Its tailroom, if any, is | |
275 | * preserved. */ | |
064af421 | 276 | void |
d295e8e9 | 277 | ofpbuf_prealloc_headroom(struct ofpbuf *b, size_t size) |
064af421 | 278 | { |
0dce369b BP |
279 | if (size > ofpbuf_headroom(b)) { |
280 | ofpbuf_resize__(b, MAX(size, 64), ofpbuf_tailroom(b)); | |
281 | } | |
064af421 BP |
282 | } |
283 | ||
1f5cbaa3 | 284 | /* Trims the size of 'b' to fit its actual content, reducing its tailroom to |
31ac1e59 BP |
285 | * 0. Its headroom, if any, is preserved. |
286 | * | |
287 | * Buffers not obtained from malloc() are not resized, since that wouldn't save | |
288 | * any memory. */ | |
064af421 BP |
289 | void |
290 | ofpbuf_trim(struct ofpbuf *b) | |
291 | { | |
0dce369b BP |
292 | if (b->source == OFPBUF_MALLOC |
293 | && (ofpbuf_headroom(b) || ofpbuf_tailroom(b))) { | |
294 | ofpbuf_resize__(b, 0, 0); | |
064af421 BP |
295 | } |
296 | } | |
297 | ||
298 | /* Appends 'size' bytes of data to the tail end of 'b', reallocating and | |
299 | * copying its data if necessary. Returns a pointer to the first byte of the | |
300 | * new data, which is left uninitialized. */ | |
301 | void * | |
d295e8e9 | 302 | ofpbuf_put_uninit(struct ofpbuf *b, size_t size) |
064af421 BP |
303 | { |
304 | void *p; | |
305 | ofpbuf_prealloc_tailroom(b, size); | |
306 | p = ofpbuf_tail(b); | |
307 | b->size += size; | |
308 | return p; | |
309 | } | |
310 | ||
311 | /* Appends 'size' zeroed bytes to the tail end of 'b'. Data in 'b' is | |
312 | * reallocated and copied if necessary. Returns a pointer to the first byte of | |
313 | * the data's location in the ofpbuf. */ | |
314 | void * | |
315 | ofpbuf_put_zeros(struct ofpbuf *b, size_t size) | |
316 | { | |
317 | void *dst = ofpbuf_put_uninit(b, size); | |
318 | memset(dst, 0, size); | |
319 | return dst; | |
320 | } | |
321 | ||
322 | /* Appends the 'size' bytes of data in 'p' to the tail end of 'b'. Data in 'b' | |
323 | * is reallocated and copied if necessary. Returns a pointer to the first | |
324 | * byte of the data's location in the ofpbuf. */ | |
325 | void * | |
d295e8e9 | 326 | ofpbuf_put(struct ofpbuf *b, const void *p, size_t size) |
064af421 BP |
327 | { |
328 | void *dst = ofpbuf_put_uninit(b, size); | |
329 | memcpy(dst, p, size); | |
330 | return dst; | |
331 | } | |
332 | ||
78090f63 BP |
333 | /* Parses as many pairs of hex digits as possible (possibly separated by |
334 | * spaces) from the beginning of 's', appending bytes for their values to 'b'. | |
335 | * Returns the first character of 's' that is not the first of a pair of hex | |
336 | * digits. If 'n' is nonnull, stores the number of bytes added to 'b' in | |
337 | * '*n'. */ | |
338 | char * | |
339 | ofpbuf_put_hex(struct ofpbuf *b, const char *s, size_t *n) | |
340 | { | |
341 | size_t initial_size = b->size; | |
342 | for (;;) { | |
343 | uint8_t byte; | |
344 | bool ok; | |
345 | ||
346 | s += strspn(s, " "); | |
347 | byte = hexits_value(s, 2, &ok); | |
348 | if (!ok) { | |
349 | if (n) { | |
350 | *n = b->size - initial_size; | |
351 | } | |
352 | return (char *) s; | |
353 | } | |
354 | ||
355 | ofpbuf_put(b, &byte, 1); | |
356 | s += 2; | |
357 | } | |
358 | } | |
359 | ||
064af421 BP |
360 | /* Reserves 'size' bytes of headroom so that they can be later allocated with |
361 | * ofpbuf_push_uninit() without reallocating the ofpbuf. */ | |
362 | void | |
d295e8e9 | 363 | ofpbuf_reserve(struct ofpbuf *b, size_t size) |
064af421 BP |
364 | { |
365 | assert(!b->size); | |
366 | ofpbuf_prealloc_tailroom(b, size); | |
367 | b->data = (char*)b->data + size; | |
368 | } | |
369 | ||
0dce369b BP |
370 | /* Prefixes 'size' bytes to the head end of 'b', reallocating and copying its |
371 | * data if necessary. Returns a pointer to the first byte of the data's | |
372 | * location in the ofpbuf. The new data is left uninitialized. */ | |
064af421 | 373 | void * |
d295e8e9 | 374 | ofpbuf_push_uninit(struct ofpbuf *b, size_t size) |
064af421 BP |
375 | { |
376 | ofpbuf_prealloc_headroom(b, size); | |
377 | b->data = (char*)b->data - size; | |
378 | b->size += size; | |
379 | return b->data; | |
380 | } | |
381 | ||
0dce369b BP |
382 | /* Prefixes 'size' zeroed bytes to the head end of 'b', reallocating and |
383 | * copying its data if necessary. Returns a pointer to the first byte of the | |
384 | * data's location in the ofpbuf. */ | |
30f07f1a BP |
385 | void * |
386 | ofpbuf_push_zeros(struct ofpbuf *b, size_t size) | |
387 | { | |
388 | void *dst = ofpbuf_push_uninit(b, size); | |
389 | memset(dst, 0, size); | |
390 | return dst; | |
391 | } | |
392 | ||
0dce369b BP |
393 | /* Copies the 'size' bytes starting at 'p' to the head end of 'b', reallocating |
394 | * and copying its data if necessary. Returns a pointer to the first byte of | |
395 | * the data's location in the ofpbuf. */ | |
064af421 | 396 | void * |
d295e8e9 | 397 | ofpbuf_push(struct ofpbuf *b, const void *p, size_t size) |
064af421 BP |
398 | { |
399 | void *dst = ofpbuf_push_uninit(b, size); | |
400 | memcpy(dst, p, size); | |
401 | return dst; | |
402 | } | |
403 | ||
404 | /* If 'b' contains at least 'offset + size' bytes of data, returns a pointer to | |
405 | * byte 'offset'. Otherwise, returns a null pointer. */ | |
406 | void * | |
d295e8e9 | 407 | ofpbuf_at(const struct ofpbuf *b, size_t offset, size_t size) |
064af421 BP |
408 | { |
409 | return offset + size <= b->size ? (char *) b->data + offset : NULL; | |
410 | } | |
411 | ||
412 | /* Returns a pointer to byte 'offset' in 'b', which must contain at least | |
413 | * 'offset + size' bytes of data. */ | |
414 | void * | |
d295e8e9 | 415 | ofpbuf_at_assert(const struct ofpbuf *b, size_t offset, size_t size) |
064af421 BP |
416 | { |
417 | assert(offset + size <= b->size); | |
418 | return ((char *) b->data) + offset; | |
419 | } | |
420 | ||
421 | /* Returns the byte following the last byte of data in use in 'b'. */ | |
422 | void * | |
d295e8e9 | 423 | ofpbuf_tail(const struct ofpbuf *b) |
064af421 BP |
424 | { |
425 | return (char *) b->data + b->size; | |
426 | } | |
427 | ||
428 | /* Returns the byte following the last byte allocated for use (but not | |
429 | * necessarily in use) by 'b'. */ | |
430 | void * | |
d295e8e9 | 431 | ofpbuf_end(const struct ofpbuf *b) |
064af421 BP |
432 | { |
433 | return (char *) b->base + b->allocated; | |
434 | } | |
435 | ||
436 | /* Clears any data from 'b'. */ | |
437 | void | |
d295e8e9 | 438 | ofpbuf_clear(struct ofpbuf *b) |
064af421 BP |
439 | { |
440 | b->data = b->base; | |
441 | b->size = 0; | |
442 | } | |
443 | ||
444 | /* Removes 'size' bytes from the head end of 'b', which must contain at least | |
445 | * 'size' bytes of data. Returns the first byte of data removed. */ | |
446 | void * | |
d295e8e9 | 447 | ofpbuf_pull(struct ofpbuf *b, size_t size) |
064af421 BP |
448 | { |
449 | void *data = b->data; | |
450 | assert(b->size >= size); | |
451 | b->data = (char*)b->data + size; | |
452 | b->size -= size; | |
453 | return data; | |
454 | } | |
455 | ||
456 | /* If 'b' has at least 'size' bytes of data, removes that many bytes from the | |
457 | * head end of 'b' and returns the first byte removed. Otherwise, returns a | |
458 | * null pointer without modifying 'b'. */ | |
459 | void * | |
d295e8e9 | 460 | ofpbuf_try_pull(struct ofpbuf *b, size_t size) |
064af421 BP |
461 | { |
462 | return b->size >= size ? ofpbuf_pull(b, size) : NULL; | |
463 | } | |
0ab8e15f BP |
464 | |
465 | /* Returns a string that describes some of 'b''s metadata plus a hex dump of up | |
466 | * to 'maxbytes' from the start of the buffer. */ | |
467 | char * | |
468 | ofpbuf_to_string(const struct ofpbuf *b, size_t maxbytes) | |
469 | { | |
470 | struct ds s; | |
471 | ||
472 | ds_init(&s); | |
473 | ds_put_format(&s, "size=%zu, allocated=%zu, head=%zu, tail=%zu\n", | |
474 | b->size, b->allocated, | |
475 | ofpbuf_headroom(b), ofpbuf_tailroom(b)); | |
476 | ds_put_hex_dump(&s, b->data, MIN(b->size, maxbytes), 0, false); | |
477 | return ds_cstr(&s); | |
478 | } | |
b3907fbc BP |
479 | |
480 | /* Removes each of the "struct ofpbuf"s on 'list' from the list and frees | |
481 | * them. */ | |
482 | void | |
483 | ofpbuf_list_delete(struct list *list) | |
484 | { | |
485 | struct ofpbuf *b, *next; | |
486 | ||
487 | LIST_FOR_EACH_SAFE (b, next, list_node, list) { | |
488 | list_remove(&b->list_node); | |
489 | ofpbuf_delete(b); | |
490 | } | |
491 | } |