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git.proxmox.com Git - mirror_ovs.git/blob - lib/ofpbuf.c
2 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 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.
21 #include "dynamic-string.h"
22 #include "netdev-dpdk.h"
26 ofpbuf_init__(struct ofpbuf
*b
, size_t allocated
, enum ofpbuf_source source
)
28 b
->allocated
= allocated
;
32 list_poison(&b
->list_node
);
36 ofpbuf_use__(struct ofpbuf
*b
, void *base
, size_t allocated
,
37 enum ofpbuf_source source
)
43 ofpbuf_init__(b
, allocated
, source
);
46 /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of
47 * memory starting at 'base'. 'base' should be the first byte of a region
48 * obtained from malloc(). It will be freed (with free()) if 'b' is resized or
51 ofpbuf_use(struct ofpbuf
*b
, void *base
, size_t allocated
)
53 ofpbuf_use__(b
, base
, allocated
, OFPBUF_MALLOC
);
56 /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of
57 * memory starting at 'base'. 'base' should point to a buffer on the stack.
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
62 * 'base' should be appropriately aligned. Using an array of uint32_t or
63 * uint64_t for the buffer is a reasonable way to ensure appropriate alignment
64 * for 32- or 64-bit data.
66 * An ofpbuf operation that requires reallocating data will assert-fail if this
67 * function was used to initialize it. Thus, one need not call ofpbuf_uninit()
68 * on an ofpbuf initialized by this function (though doing so is harmless),
69 * because it is guaranteed that 'b' does not own any heap-allocated memory. */
71 ofpbuf_use_stack(struct ofpbuf
*b
, void *base
, size_t allocated
)
73 ofpbuf_use__(b
, base
, allocated
, OFPBUF_STACK
);
76 /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of
77 * memory starting at 'base'. 'base' should point to a buffer on the stack.
78 * (Nothing actually relies on 'base' being allocated on the stack. It could
79 * be static or malloc()'d memory. But stack space is the most common use
82 * 'base' should be appropriately aligned. Using an array of uint32_t or
83 * uint64_t for the buffer is a reasonable way to ensure appropriate alignment
84 * for 32- or 64-bit data.
86 * An ofpbuf operation that requires reallocating data will copy the provided
87 * buffer into a malloc()'d buffer. Thus, it is wise to call ofpbuf_uninit()
88 * on an ofpbuf initialized by this function, so that if it expanded into the
89 * heap, that memory is freed. */
91 ofpbuf_use_stub(struct ofpbuf
*b
, void *base
, size_t allocated
)
93 ofpbuf_use__(b
, base
, allocated
, OFPBUF_STUB
);
96 /* Initializes 'b' as an ofpbuf whose data starts at 'data' and continues for
97 * 'size' bytes. This is appropriate for an ofpbuf that will be used to
98 * inspect existing data, without moving it around or reallocating it, and
99 * generally without modifying it at all.
101 * An ofpbuf operation that requires reallocating data will assert-fail if this
102 * function was used to initialize it. */
104 ofpbuf_use_const(struct ofpbuf
*b
, const void *data
, size_t size
)
106 ofpbuf_use__(b
, CONST_CAST(void *, data
), size
, OFPBUF_STACK
);
110 /* Initializes 'b' as an empty ofpbuf with an initial capacity of 'size'
113 ofpbuf_init(struct ofpbuf
*b
, size_t size
)
115 ofpbuf_use(b
, size
? xmalloc(size
) : NULL
, size
);
118 /* Frees memory that 'b' points to. */
120 ofpbuf_uninit(struct ofpbuf
*b
)
123 if (b
->source
== OFPBUF_MALLOC
) {
129 /* Frees memory that 'b' points to and allocates a new ofpbuf */
131 ofpbuf_reinit(struct ofpbuf
*b
, size_t size
)
134 ofpbuf_init(b
, size
);
137 /* Creates and returns a new ofpbuf with an initial capacity of 'size'
140 ofpbuf_new(size_t size
)
142 struct ofpbuf
*b
= xmalloc(sizeof *b
);
143 ofpbuf_init(b
, size
);
147 /* Creates and returns a new ofpbuf with an initial capacity of 'size +
148 * headroom' bytes, reserving the first 'headroom' bytes as headroom. */
150 ofpbuf_new_with_headroom(size_t size
, size_t headroom
)
152 struct ofpbuf
*b
= ofpbuf_new(size
+ headroom
);
153 ofpbuf_reserve(b
, headroom
);
157 /* Creates and returns a new ofpbuf that initially contains a copy of the
158 * 'buffer->size' bytes of data starting at 'buffer->data' with no headroom or
161 ofpbuf_clone(const struct ofpbuf
*buffer
)
163 return ofpbuf_clone_with_headroom(buffer
, 0);
166 /* Creates and returns a new ofpbuf whose data are copied from 'buffer'. The
167 * returned ofpbuf will additionally have 'headroom' bytes of headroom. */
169 ofpbuf_clone_with_headroom(const struct ofpbuf
*buffer
, size_t headroom
)
171 struct ofpbuf
*new_buffer
;
173 new_buffer
= ofpbuf_clone_data_with_headroom(buffer
->data
,
176 if (buffer
->header
) {
178 = (char *)new_buffer
->data
- (char *)buffer
->data
;
180 new_buffer
->header
= (char *) buffer
->header
+ data_delta
;
182 new_buffer
->msg
= buffer
->msg
;
187 /* Creates and returns a new ofpbuf that initially contains a copy of the
188 * 'size' bytes of data starting at 'data' with no headroom or tailroom. */
190 ofpbuf_clone_data(const void *data
, size_t size
)
192 return ofpbuf_clone_data_with_headroom(data
, size
, 0);
195 /* Creates and returns a new ofpbuf that initially contains 'headroom' bytes of
196 * headroom followed by a copy of the 'size' bytes of data starting at
199 ofpbuf_clone_data_with_headroom(const void *data
, size_t size
, size_t headroom
)
201 struct ofpbuf
*b
= ofpbuf_new_with_headroom(size
, headroom
);
202 ofpbuf_put(b
, data
, size
);
207 ofpbuf_copy__(struct ofpbuf
*b
, uint8_t *new_base
,
208 size_t new_headroom
, size_t new_tailroom
)
210 const uint8_t *old_base
= b
->base
;
211 size_t old_headroom
= ofpbuf_headroom(b
);
212 size_t old_tailroom
= ofpbuf_tailroom(b
);
213 size_t copy_headroom
= MIN(old_headroom
, new_headroom
);
214 size_t copy_tailroom
= MIN(old_tailroom
, new_tailroom
);
216 memcpy(&new_base
[new_headroom
- copy_headroom
],
217 &old_base
[old_headroom
- copy_headroom
],
218 copy_headroom
+ b
->size
+ copy_tailroom
);
221 /* Reallocates 'b' so that it has exactly 'new_headroom' and 'new_tailroom'
222 * bytes of headroom and tailroom, respectively. */
224 ofpbuf_resize__(struct ofpbuf
*b
, size_t new_headroom
, size_t new_tailroom
)
226 void *new_base
, *new_data
;
227 size_t new_allocated
;
229 new_allocated
= new_headroom
+ b
->size
+ new_tailroom
;
233 if (new_headroom
== ofpbuf_headroom(b
)) {
234 new_base
= xrealloc(b
->base
, new_allocated
);
236 new_base
= xmalloc(new_allocated
);
237 ofpbuf_copy__(b
, new_base
, new_headroom
, new_tailroom
);
246 b
->source
= OFPBUF_MALLOC
;
247 new_base
= xmalloc(new_allocated
);
248 ofpbuf_copy__(b
, new_base
, new_headroom
, new_tailroom
);
255 b
->allocated
= new_allocated
;
258 new_data
= (char *) new_base
+ new_headroom
;
259 if (b
->data
!= new_data
) {
261 uintptr_t data_delta
= (char *) new_data
- (char *) b
->data
;
263 b
->header
= (char *) b
->header
+ data_delta
;
269 /* Ensures that 'b' has room for at least 'size' bytes at its tail end,
270 * reallocating and copying its data if necessary. Its headroom, if any, is
273 ofpbuf_prealloc_tailroom(struct ofpbuf
*b
, size_t size
)
275 if (size
> ofpbuf_tailroom(b
)) {
276 ofpbuf_resize__(b
, ofpbuf_headroom(b
), MAX(size
, 64));
280 /* Ensures that 'b' has room for at least 'size' bytes at its head,
281 * reallocating and copying its data if necessary. Its tailroom, if any, is
284 ofpbuf_prealloc_headroom(struct ofpbuf
*b
, size_t size
)
286 if (size
> ofpbuf_headroom(b
)) {
287 ofpbuf_resize__(b
, MAX(size
, 64), ofpbuf_tailroom(b
));
291 /* Trims the size of 'b' to fit its actual content, reducing its headroom and
292 * tailroom to 0, if any.
294 * Buffers not obtained from malloc() are not resized, since that wouldn't save
297 ofpbuf_trim(struct ofpbuf
*b
)
299 if (b
->source
== OFPBUF_MALLOC
300 && (ofpbuf_headroom(b
) || ofpbuf_tailroom(b
))) {
301 ofpbuf_resize__(b
, 0, 0);
305 /* If 'b' is shorter than 'length' bytes, pads its tail out with zeros to that
308 ofpbuf_padto(struct ofpbuf
*b
, size_t length
)
310 if (b
->size
< length
) {
311 ofpbuf_put_zeros(b
, length
- b
->size
);
315 /* Shifts all of the data within the allocated space in 'b' by 'delta' bytes.
316 * For example, a 'delta' of 1 would cause each byte of data to move one byte
317 * forward (from address 'p' to 'p+1'), and a 'delta' of -1 would cause each
318 * byte to move one byte backward (from 'p' to 'p-1'). */
320 ofpbuf_shift(struct ofpbuf
*b
, int delta
)
322 ovs_assert(delta
> 0 ? delta
<= ofpbuf_tailroom(b
)
323 : delta
< 0 ? -delta
<= ofpbuf_headroom(b
)
327 char *dst
= (char *) b
->data
+ delta
;
328 memmove(dst
, b
->data
, b
->size
);
333 /* Appends 'size' bytes of data to the tail end of 'b', reallocating and
334 * copying its data if necessary. Returns a pointer to the first byte of the
335 * new data, which is left uninitialized. */
337 ofpbuf_put_uninit(struct ofpbuf
*b
, size_t size
)
340 ofpbuf_prealloc_tailroom(b
, size
);
346 /* Appends 'size' zeroed bytes to the tail end of 'b'. Data in 'b' is
347 * reallocated and copied if necessary. Returns a pointer to the first byte of
348 * the data's location in the ofpbuf. */
350 ofpbuf_put_zeros(struct ofpbuf
*b
, size_t size
)
352 void *dst
= ofpbuf_put_uninit(b
, size
);
353 memset(dst
, 0, size
);
357 /* Appends the 'size' bytes of data in 'p' to the tail end of 'b'. Data in 'b'
358 * is reallocated and copied if necessary. Returns a pointer to the first
359 * byte of the data's location in the ofpbuf. */
361 ofpbuf_put(struct ofpbuf
*b
, const void *p
, size_t size
)
363 void *dst
= ofpbuf_put_uninit(b
, size
);
364 memcpy(dst
, p
, size
);
368 /* Parses as many pairs of hex digits as possible (possibly separated by
369 * spaces) from the beginning of 's', appending bytes for their values to 'b'.
370 * Returns the first character of 's' that is not the first of a pair of hex
371 * digits. If 'n' is nonnull, stores the number of bytes added to 'b' in
374 ofpbuf_put_hex(struct ofpbuf
*b
, const char *s
, size_t *n
)
376 size_t initial_size
= b
->size
;
381 s
+= strspn(s
, " \t\r\n");
382 byte
= hexits_value(s
, 2, &ok
);
385 *n
= b
->size
- initial_size
;
387 return CONST_CAST(char *, s
);
390 ofpbuf_put(b
, &byte
, 1);
395 /* Reserves 'size' bytes of headroom so that they can be later allocated with
396 * ofpbuf_push_uninit() without reallocating the ofpbuf. */
398 ofpbuf_reserve(struct ofpbuf
*b
, size_t size
)
400 ovs_assert(!b
->size
);
401 ofpbuf_prealloc_tailroom(b
, size
);
402 b
->data
= (char*)b
->data
+ size
;
405 /* Prefixes 'size' bytes to the head end of 'b', reallocating and copying its
406 * data if necessary. Returns a pointer to the first byte of the data's
407 * location in the ofpbuf. The new data is left uninitialized. */
409 ofpbuf_push_uninit(struct ofpbuf
*b
, size_t size
)
411 ofpbuf_prealloc_headroom(b
, size
);
412 b
->data
= (char*)b
->data
- size
;
417 /* Prefixes 'size' zeroed bytes to the head end of 'b', reallocating and
418 * copying its data if necessary. Returns a pointer to the first byte of the
419 * data's location in the ofpbuf. */
421 ofpbuf_push_zeros(struct ofpbuf
*b
, size_t size
)
423 void *dst
= ofpbuf_push_uninit(b
, size
);
424 memset(dst
, 0, size
);
428 /* Copies the 'size' bytes starting at 'p' to the head end of 'b', reallocating
429 * and copying its data if necessary. Returns a pointer to the first byte of
430 * the data's location in the ofpbuf. */
432 ofpbuf_push(struct ofpbuf
*b
, const void *p
, size_t size
)
434 void *dst
= ofpbuf_push_uninit(b
, size
);
435 memcpy(dst
, p
, size
);
439 /* Returns the data in 'b' as a block of malloc()'d memory and frees the buffer
440 * within 'b'. (If 'b' itself was dynamically allocated, e.g. with
441 * ofpbuf_new(), then it should still be freed with, e.g., ofpbuf_delete().) */
443 ofpbuf_steal_data(struct ofpbuf
*b
)
447 if (b
->source
== OFPBUF_MALLOC
&& b
->data
== b
->base
) {
450 p
= xmemdup(b
->data
, b
->size
);
451 if (b
->source
== OFPBUF_MALLOC
) {
460 /* Returns a string that describes some of 'b''s metadata plus a hex dump of up
461 * to 'maxbytes' from the start of the buffer. */
463 ofpbuf_to_string(const struct ofpbuf
*b
, size_t maxbytes
)
468 ds_put_format(&s
, "size=%"PRIu32
", allocated=%"PRIu32
", head=%"PRIuSIZE
", tail=%"PRIuSIZE
"\n",
469 b
->size
, b
->allocated
,
470 ofpbuf_headroom(b
), ofpbuf_tailroom(b
));
471 ds_put_hex_dump(&s
, b
->data
, MIN(b
->size
, maxbytes
), 0, false);
475 /* Removes each of the "struct ofpbuf"s on 'list' from the list and frees
478 ofpbuf_list_delete(struct ovs_list
*list
)
482 LIST_FOR_EACH_POP (b
, list_node
, list
) {