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git.proxmox.com Git - mirror_ovs.git/blob - lib/ofpbuf.c
2 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2016 Nicira, Inc.
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:
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
18 #include "openvswitch/ofpbuf.h"
21 #include "openvswitch/dynamic-string.h"
25 ofpbuf_init__(struct ofpbuf
*b
, size_t allocated
, enum ofpbuf_source source
)
27 b
->allocated
= allocated
;
31 ovs_list_poison(&b
->list_node
);
35 ofpbuf_use__(struct ofpbuf
*b
, void *base
, size_t allocated
, size_t size
,
36 enum ofpbuf_source source
)
42 ofpbuf_init__(b
, allocated
, source
);
45 /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of
46 * memory starting at 'base'. 'base' should be the first byte of a region
47 * obtained from malloc(). It will be freed (with free()) if 'b' is resized or
50 ofpbuf_use(struct ofpbuf
*b
, void *base
, size_t allocated
)
52 ofpbuf_use__(b
, base
, allocated
, 0, OFPBUF_MALLOC
);
55 /* Converts ds into ofpbuf 'b'. 'b' contains the 'ds->allocated' bytes of
56 * memory starting at 'ds->string'. 'ds' should not be modified any more.
57 * The memory allocated for 'ds' will be freed (with free()) if 'b' is
58 * resized or freed. */
60 ofpbuf_use_ds(struct ofpbuf
*b
, const struct ds
*ds
)
62 ofpbuf_use__(b
, ds
->string
, ds
->allocated
+ 1, ds
->length
, OFPBUF_MALLOC
);
65 /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of
66 * memory starting at 'base'. 'base' should point to a buffer on the stack.
67 * (Nothing actually relies on 'base' being allocated on the stack. It could
68 * be static or malloc()'d memory. But stack space is the most common use
71 * 'base' should be appropriately aligned. Using an array of uint32_t or
72 * uint64_t for the buffer is a reasonable way to ensure appropriate alignment
73 * for 32- or 64-bit data.
75 * An ofpbuf operation that requires reallocating data will assert-fail if this
76 * function was used to initialize it. Thus, one need not call ofpbuf_uninit()
77 * on an ofpbuf initialized by this function (though doing so is harmless),
78 * because it is guaranteed that 'b' does not own any heap-allocated memory. */
80 ofpbuf_use_stack(struct ofpbuf
*b
, void *base
, size_t allocated
)
82 ofpbuf_use__(b
, base
, allocated
, 0, OFPBUF_STACK
);
85 /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of
86 * memory starting at 'base'. 'base' should point to a buffer on the stack.
87 * (Nothing actually relies on 'base' being allocated on the stack. It could
88 * be static or malloc()'d memory. But stack space is the most common use
91 * 'base' should be appropriately aligned. Using an array of uint32_t or
92 * uint64_t for the buffer is a reasonable way to ensure appropriate alignment
93 * for 32- or 64-bit data.
95 * An ofpbuf operation that requires reallocating data will copy the provided
96 * buffer into a malloc()'d buffer. Thus, it is wise to call ofpbuf_uninit()
97 * on an ofpbuf initialized by this function, so that if it expanded into the
98 * heap, that memory is freed. */
100 ofpbuf_use_stub(struct ofpbuf
*b
, void *base
, size_t allocated
)
102 ofpbuf_use__(b
, base
, allocated
, 0, OFPBUF_STUB
);
105 /* Initializes 'b' as an ofpbuf whose data starts at 'data' and continues for
106 * 'size' bytes. This is appropriate for an ofpbuf that will be used to
107 * inspect existing data, without moving it around or reallocating it, and
108 * generally without modifying it at all.
110 * An ofpbuf operation that requires reallocating data will assert-fail if this
111 * function was used to initialize it. */
113 ofpbuf_use_const(struct ofpbuf
*b
, const void *data
, size_t size
)
115 ofpbuf_use__(b
, CONST_CAST(void *, data
), size
, size
, OFPBUF_STACK
);
118 /* Initializes 'b' as an empty ofpbuf with an initial capacity of 'size'
121 ofpbuf_init(struct ofpbuf
*b
, size_t size
)
123 ofpbuf_use(b
, size
? xmalloc(size
) : NULL
, size
);
126 /* Frees memory that 'b' points to. */
128 ofpbuf_uninit(struct ofpbuf
*b
)
131 if (b
->source
== OFPBUF_MALLOC
) {
137 /* Frees memory that 'b' points to and allocates a new ofpbuf */
139 ofpbuf_reinit(struct ofpbuf
*b
, size_t size
)
142 ofpbuf_init(b
, size
);
145 /* Creates and returns a new ofpbuf with an initial capacity of 'size'
148 ofpbuf_new(size_t size
)
150 struct ofpbuf
*b
= xmalloc(sizeof *b
);
151 ofpbuf_init(b
, size
);
155 /* Creates and returns a new ofpbuf with an initial capacity of 'size +
156 * headroom' bytes, reserving the first 'headroom' bytes as headroom. */
158 ofpbuf_new_with_headroom(size_t size
, size_t headroom
)
160 struct ofpbuf
*b
= ofpbuf_new(size
+ headroom
);
161 ofpbuf_reserve(b
, headroom
);
165 /* Creates and returns a new ofpbuf that initially contains a copy of the
166 * 'buffer->size' bytes of data starting at 'buffer->data' with no headroom or
169 ofpbuf_clone(const struct ofpbuf
*buffer
)
171 return ofpbuf_clone_with_headroom(buffer
, 0);
174 /* Creates and returns a new ofpbuf whose data are copied from 'buffer'. The
175 * returned ofpbuf will additionally have 'headroom' bytes of headroom. */
177 ofpbuf_clone_with_headroom(const struct ofpbuf
*b
, size_t headroom
)
179 struct ofpbuf
*new_buffer
;
181 new_buffer
= ofpbuf_clone_data_with_headroom(b
->data
, b
->size
, headroom
);
183 ptrdiff_t header_offset
= (char *) b
->header
- (char *) b
->data
;
185 new_buffer
->header
= (char *) new_buffer
->data
+ header_offset
;
188 ptrdiff_t msg_offset
= (char *) b
->msg
- (char *) b
->data
;
190 new_buffer
->msg
= (char *) new_buffer
->data
+ msg_offset
;
196 /* Creates and returns a new ofpbuf that initially contains a copy of the
197 * 'size' bytes of data starting at 'data' with no headroom or tailroom. */
199 ofpbuf_clone_data(const void *data
, size_t size
)
201 return ofpbuf_clone_data_with_headroom(data
, size
, 0);
204 /* Creates and returns a new ofpbuf that initially contains 'headroom' bytes of
205 * headroom followed by a copy of the 'size' bytes of data starting at
208 ofpbuf_clone_data_with_headroom(const void *data
, size_t size
, size_t headroom
)
210 struct ofpbuf
*b
= ofpbuf_new_with_headroom(size
, headroom
);
211 ofpbuf_put(b
, data
, size
);
216 ofpbuf_copy__(struct ofpbuf
*b
, uint8_t *new_base
,
217 size_t new_headroom
, size_t new_tailroom
)
219 const uint8_t *old_base
= b
->base
;
220 size_t old_headroom
= ofpbuf_headroom(b
);
221 size_t old_tailroom
= ofpbuf_tailroom(b
);
222 size_t copy_headroom
= MIN(old_headroom
, new_headroom
);
223 size_t copy_tailroom
= MIN(old_tailroom
, new_tailroom
);
225 memcpy(&new_base
[new_headroom
- copy_headroom
],
226 &old_base
[old_headroom
- copy_headroom
],
227 copy_headroom
+ b
->size
+ copy_tailroom
);
230 /* Reallocates 'b' so that it has exactly 'new_headroom' and 'new_tailroom'
231 * bytes of headroom and tailroom, respectively. */
233 ofpbuf_resize__(struct ofpbuf
*b
, size_t new_headroom
, size_t new_tailroom
)
235 void *new_base
, *new_data
;
236 size_t new_allocated
;
238 new_allocated
= new_headroom
+ b
->size
+ new_tailroom
;
242 if (new_headroom
== ofpbuf_headroom(b
)) {
243 new_base
= xrealloc(b
->base
, new_allocated
);
245 new_base
= xmalloc(new_allocated
);
246 ofpbuf_copy__(b
, new_base
, new_headroom
, new_tailroom
);
255 b
->source
= OFPBUF_MALLOC
;
256 new_base
= xmalloc(new_allocated
);
257 ofpbuf_copy__(b
, new_base
, new_headroom
, new_tailroom
);
264 b
->allocated
= new_allocated
;
267 new_data
= (char *) new_base
+ new_headroom
;
268 if (b
->data
!= new_data
) {
270 ptrdiff_t header_offset
= (char *) b
->header
- (char *) b
->data
;
272 b
->header
= (char *) new_data
+ header_offset
;
275 ptrdiff_t msg_offset
= (char *) b
->msg
- (char *) b
->data
;
277 b
->msg
= (char *) new_data
+ msg_offset
;
283 /* Ensures that 'b' has room for at least 'size' bytes at its tail end,
284 * reallocating and copying its data if necessary. Its headroom, if any, is
287 ofpbuf_prealloc_tailroom(struct ofpbuf
*b
, size_t size
)
289 if (size
> ofpbuf_tailroom(b
)) {
290 ofpbuf_resize__(b
, ofpbuf_headroom(b
), MAX(size
, 64));
294 /* Ensures that 'b' has room for at least 'size' bytes at its head,
295 * reallocating and copying its data if necessary. Its tailroom, if any, is
298 ofpbuf_prealloc_headroom(struct ofpbuf
*b
, size_t size
)
300 if (size
> ofpbuf_headroom(b
)) {
301 ofpbuf_resize__(b
, MAX(size
, 64), ofpbuf_tailroom(b
));
305 /* Trims the size of 'b' to fit its actual content, reducing its headroom and
306 * tailroom to 0, if any.
308 * Buffers not obtained from malloc() are not resized, since that wouldn't save
311 * Caller needs to updates 'b->header' and 'b->msg' so that they point to the
312 * same locations in the data. (If they pointed into the tailroom or headroom
313 * then they become invalid.)
317 ofpbuf_trim(struct ofpbuf
*b
)
319 if (b
->source
== OFPBUF_MALLOC
320 && (ofpbuf_headroom(b
) || ofpbuf_tailroom(b
))) {
321 ofpbuf_resize__(b
, 0, 0);
325 /* If 'b' is shorter than 'length' bytes, pads its tail out with zeros to that
328 ofpbuf_padto(struct ofpbuf
*b
, size_t length
)
330 if (b
->size
< length
) {
331 ofpbuf_put_zeros(b
, length
- b
->size
);
335 /* Shifts all of the data within the allocated space in 'b' by 'delta' bytes.
336 * For example, a 'delta' of 1 would cause each byte of data to move one byte
337 * forward (from address 'p' to 'p+1'), and a 'delta' of -1 would cause each
338 * byte to move one byte backward (from 'p' to 'p-1').
340 * If used, user must make sure the 'header' and 'msg' pointers are updated
344 ofpbuf_shift(struct ofpbuf
*b
, int delta
)
346 ovs_assert(delta
> 0 ? delta
<= ofpbuf_tailroom(b
)
347 : delta
< 0 ? -delta
<= ofpbuf_headroom(b
)
351 char *dst
= (char *) b
->data
+ delta
;
352 memmove(dst
, b
->data
, b
->size
);
357 /* Appends 'size' bytes of data to the tail end of 'b', reallocating and
358 * copying its data if necessary. Returns a pointer to the first byte of the
359 * new data, which is left uninitialized. */
361 ofpbuf_put_uninit(struct ofpbuf
*b
, size_t size
)
364 ofpbuf_prealloc_tailroom(b
, size
);
370 /* Appends 'size' zeroed bytes to the tail end of 'b'. Data in 'b' is
371 * reallocated and copied if necessary. Returns a pointer to the first byte of
372 * the data's location in the ofpbuf. */
374 ofpbuf_put_zeros(struct ofpbuf
*b
, size_t size
)
376 void *dst
= ofpbuf_put_uninit(b
, size
);
377 nullable_memset(dst
, 0, size
);
381 /* Appends the 'size' bytes of data in 'p' to the tail end of 'b'. Data in 'b'
382 * is reallocated and copied if necessary. Returns a pointer to the first
383 * byte of the data's location in the ofpbuf. */
385 ofpbuf_put(struct ofpbuf
*b
, const void *p
, size_t size
)
387 void *dst
= ofpbuf_put_uninit(b
, size
);
388 memcpy(dst
, p
, size
);
392 /* Parses as many pairs of hex digits as possible (possibly separated by spaces
393 * or periods) from the beginning of 's', appending bytes for their values to
394 * 'b'. Returns the first character of 's' that is not the first of a pair of
395 * hex digits. If 'n' is nonnull, stores the number of bytes added to 'b' in
398 ofpbuf_put_hex(struct ofpbuf
*b
, const char *s
, size_t *n
)
400 size_t initial_size
= b
->size
;
405 s
+= strspn(s
, " .\t\r\n");
406 byte
= hexits_value(s
, 2, &ok
);
409 *n
= b
->size
- initial_size
;
411 return CONST_CAST(char *, s
);
414 ofpbuf_put(b
, &byte
, 1);
419 /* Reserves 'size' bytes of headroom so that they can be later allocated with
420 * ofpbuf_push_uninit() without reallocating the ofpbuf. */
422 ofpbuf_reserve(struct ofpbuf
*b
, size_t size
)
424 ovs_assert(!b
->size
);
425 ofpbuf_prealloc_tailroom(b
, size
);
426 b
->data
= (char*)b
->data
+ size
;
429 /* Prefixes 'size' bytes to the head end of 'b', reallocating and copying its
430 * data if necessary. Returns a pointer to the first byte of the data's
431 * location in the ofpbuf. The new data is left uninitialized. */
433 ofpbuf_push_uninit(struct ofpbuf
*b
, size_t size
)
435 ofpbuf_prealloc_headroom(b
, size
);
436 b
->data
= (char*)b
->data
- size
;
441 /* Prefixes 'size' zeroed bytes to the head end of 'b', reallocating and
442 * copying its data if necessary. Returns a pointer to the first byte of the
443 * data's location in the ofpbuf. */
445 ofpbuf_push_zeros(struct ofpbuf
*b
, size_t size
)
447 void *dst
= ofpbuf_push_uninit(b
, size
);
448 memset(dst
, 0, size
);
452 /* Copies the 'size' bytes starting at 'p' to the head end of 'b', reallocating
453 * and copying its data if necessary. Returns a pointer to the first byte of
454 * the data's location in the ofpbuf. */
456 ofpbuf_push(struct ofpbuf
*b
, const void *p
, size_t size
)
458 void *dst
= ofpbuf_push_uninit(b
, size
);
459 memcpy(dst
, p
, size
);
463 /* Inserts the 'n' bytes of 'data' into 'b' starting at the given 'offset',
464 * moving data forward as necessary to make room.
466 * 'data' must not point inside 'b'. */
468 ofpbuf_insert(struct ofpbuf
*b
, size_t offset
, const void *data
, size_t n
)
470 if (offset
< b
->size
) {
471 ofpbuf_put_uninit(b
, n
); /* b->size gets increased. */
472 memmove((char *) b
->data
+ offset
+ n
, (char *) b
->data
+ offset
,
473 b
->size
- offset
- n
);
474 memcpy((char *) b
->data
+ offset
, data
, n
);
476 ovs_assert(offset
== b
->size
);
477 ofpbuf_put(b
, data
, n
);
481 /* Returns the data in 'b' as a block of malloc()'d memory and frees the buffer
482 * within 'b'. (If 'b' itself was dynamically allocated, e.g. with
483 * ofpbuf_new(), then it should still be freed with, e.g., ofpbuf_delete().) */
485 ofpbuf_steal_data(struct ofpbuf
*b
)
489 if (b
->source
== OFPBUF_MALLOC
&& b
->data
== b
->base
) {
492 p
= xmemdup(b
->data
, b
->size
);
493 if (b
->source
== OFPBUF_MALLOC
) {
504 /* Returns a string that describes some of 'b''s metadata plus a hex dump of up
505 * to 'maxbytes' from the start of the buffer. */
507 ofpbuf_to_string(const struct ofpbuf
*b
, size_t maxbytes
)
512 ds_put_format(&s
, "size=%"PRIu32
", allocated=%"PRIu32
", head=%"PRIuSIZE
", tail=%"PRIuSIZE
"\n",
513 b
->size
, b
->allocated
,
514 ofpbuf_headroom(b
), ofpbuf_tailroom(b
));
515 ds_put_hex_dump(&s
, b
->data
, MIN(b
->size
, maxbytes
), 0, false);
519 /* Removes each of the "struct ofpbuf"s on 'list' from the list and frees
522 ofpbuf_list_delete(struct ovs_list
*list
)
526 LIST_FOR_EACH_POP (b
, list_node
, list
) {