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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"
22 #include "netdev-dpdk.h"
26 ofpbuf_init__(struct ofpbuf
*b
, size_t allocated
, enum ofpbuf_source source
)
28 b
->allocated
= allocated
;
32 ovs_list_poison(&b
->list_node
);
36 ofpbuf_use__(struct ofpbuf
*b
, void *base
, size_t allocated
, size_t size
,
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
, 0, OFPBUF_MALLOC
);
56 /* Converts ds into ofpbuf 'b'. 'b' contains the 'ds->allocated' bytes of
57 * memory starting at 'ds->string'. 'ds' should not be modified any more.
58 * The memory allocated for 'ds' will be freed (with free()) if 'b' is
59 * resized or freed. */
61 ofpbuf_use_ds(struct ofpbuf
*b
, const struct ds
*ds
)
63 ofpbuf_use__(b
, ds
->string
, ds
->allocated
+ 1, ds
->length
, OFPBUF_MALLOC
);
66 /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of
67 * memory starting at 'base'. 'base' should point to a buffer on the stack.
68 * (Nothing actually relies on 'base' being allocated on the stack. It could
69 * be static or malloc()'d memory. But stack space is the most common use
72 * 'base' should be appropriately aligned. Using an array of uint32_t or
73 * uint64_t for the buffer is a reasonable way to ensure appropriate alignment
74 * for 32- or 64-bit data.
76 * An ofpbuf operation that requires reallocating data will assert-fail if this
77 * function was used to initialize it. Thus, one need not call ofpbuf_uninit()
78 * on an ofpbuf initialized by this function (though doing so is harmless),
79 * because it is guaranteed that 'b' does not own any heap-allocated memory. */
81 ofpbuf_use_stack(struct ofpbuf
*b
, void *base
, size_t allocated
)
83 ofpbuf_use__(b
, base
, allocated
, 0, OFPBUF_STACK
);
86 /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of
87 * memory starting at 'base'. 'base' should point to a buffer on the stack.
88 * (Nothing actually relies on 'base' being allocated on the stack. It could
89 * be static or malloc()'d memory. But stack space is the most common use
92 * 'base' should be appropriately aligned. Using an array of uint32_t or
93 * uint64_t for the buffer is a reasonable way to ensure appropriate alignment
94 * for 32- or 64-bit data.
96 * An ofpbuf operation that requires reallocating data will copy the provided
97 * buffer into a malloc()'d buffer. Thus, it is wise to call ofpbuf_uninit()
98 * on an ofpbuf initialized by this function, so that if it expanded into the
99 * heap, that memory is freed. */
101 ofpbuf_use_stub(struct ofpbuf
*b
, void *base
, size_t allocated
)
103 ofpbuf_use__(b
, base
, allocated
, 0, OFPBUF_STUB
);
106 /* Initializes 'b' as an ofpbuf whose data starts at 'data' and continues for
107 * 'size' bytes. This is appropriate for an ofpbuf that will be used to
108 * inspect existing data, without moving it around or reallocating it, and
109 * generally without modifying it at all.
111 * An ofpbuf operation that requires reallocating data will assert-fail if this
112 * function was used to initialize it. */
114 ofpbuf_use_const(struct ofpbuf
*b
, const void *data
, size_t size
)
116 ofpbuf_use__(b
, CONST_CAST(void *, data
), size
, size
, OFPBUF_STACK
);
119 /* Initializes 'b' as an empty ofpbuf with an initial capacity of 'size'
122 ofpbuf_init(struct ofpbuf
*b
, size_t size
)
124 ofpbuf_use(b
, size
? xmalloc(size
) : NULL
, size
);
127 /* Frees memory that 'b' points to. */
129 ofpbuf_uninit(struct ofpbuf
*b
)
132 if (b
->source
== OFPBUF_MALLOC
) {
138 /* Frees memory that 'b' points to and allocates a new ofpbuf */
140 ofpbuf_reinit(struct ofpbuf
*b
, size_t size
)
143 ofpbuf_init(b
, size
);
146 /* Creates and returns a new ofpbuf with an initial capacity of 'size'
149 ofpbuf_new(size_t size
)
151 struct ofpbuf
*b
= xmalloc(sizeof *b
);
152 ofpbuf_init(b
, size
);
156 /* Creates and returns a new ofpbuf with an initial capacity of 'size +
157 * headroom' bytes, reserving the first 'headroom' bytes as headroom. */
159 ofpbuf_new_with_headroom(size_t size
, size_t headroom
)
161 struct ofpbuf
*b
= ofpbuf_new(size
+ headroom
);
162 ofpbuf_reserve(b
, headroom
);
166 /* Creates and returns a new ofpbuf that initially contains a copy of the
167 * 'buffer->size' bytes of data starting at 'buffer->data' with no headroom or
170 ofpbuf_clone(const struct ofpbuf
*buffer
)
172 return ofpbuf_clone_with_headroom(buffer
, 0);
175 /* Creates and returns a new ofpbuf whose data are copied from 'buffer'. The
176 * returned ofpbuf will additionally have 'headroom' bytes of headroom. */
178 ofpbuf_clone_with_headroom(const struct ofpbuf
*b
, size_t headroom
)
180 struct ofpbuf
*new_buffer
;
182 new_buffer
= ofpbuf_clone_data_with_headroom(b
->data
, b
->size
, headroom
);
184 ptrdiff_t header_offset
= (char *) b
->header
- (char *) b
->data
;
186 new_buffer
->header
= (char *) new_buffer
->data
+ header_offset
;
189 ptrdiff_t msg_offset
= (char *) b
->msg
- (char *) b
->data
;
191 new_buffer
->msg
= (char *) new_buffer
->data
+ msg_offset
;
197 /* Creates and returns a new ofpbuf that initially contains a copy of the
198 * 'size' bytes of data starting at 'data' with no headroom or tailroom. */
200 ofpbuf_clone_data(const void *data
, size_t size
)
202 return ofpbuf_clone_data_with_headroom(data
, size
, 0);
205 /* Creates and returns a new ofpbuf that initially contains 'headroom' bytes of
206 * headroom followed by a copy of the 'size' bytes of data starting at
209 ofpbuf_clone_data_with_headroom(const void *data
, size_t size
, size_t headroom
)
211 struct ofpbuf
*b
= ofpbuf_new_with_headroom(size
, headroom
);
212 ofpbuf_put(b
, data
, size
);
217 ofpbuf_copy__(struct ofpbuf
*b
, uint8_t *new_base
,
218 size_t new_headroom
, size_t new_tailroom
)
220 const uint8_t *old_base
= b
->base
;
221 size_t old_headroom
= ofpbuf_headroom(b
);
222 size_t old_tailroom
= ofpbuf_tailroom(b
);
223 size_t copy_headroom
= MIN(old_headroom
, new_headroom
);
224 size_t copy_tailroom
= MIN(old_tailroom
, new_tailroom
);
226 memcpy(&new_base
[new_headroom
- copy_headroom
],
227 &old_base
[old_headroom
- copy_headroom
],
228 copy_headroom
+ b
->size
+ copy_tailroom
);
231 /* Reallocates 'b' so that it has exactly 'new_headroom' and 'new_tailroom'
232 * bytes of headroom and tailroom, respectively. */
234 ofpbuf_resize__(struct ofpbuf
*b
, size_t new_headroom
, size_t new_tailroom
)
236 void *new_base
, *new_data
;
237 size_t new_allocated
;
239 new_allocated
= new_headroom
+ b
->size
+ new_tailroom
;
243 if (new_headroom
== ofpbuf_headroom(b
)) {
244 new_base
= xrealloc(b
->base
, new_allocated
);
246 new_base
= xmalloc(new_allocated
);
247 ofpbuf_copy__(b
, new_base
, new_headroom
, new_tailroom
);
256 b
->source
= OFPBUF_MALLOC
;
257 new_base
= xmalloc(new_allocated
);
258 ofpbuf_copy__(b
, new_base
, new_headroom
, new_tailroom
);
265 b
->allocated
= new_allocated
;
268 new_data
= (char *) new_base
+ new_headroom
;
269 if (b
->data
!= new_data
) {
271 ptrdiff_t header_offset
= (char *) b
->header
- (char *) b
->data
;
273 b
->header
= (char *) new_data
+ header_offset
;
276 ptrdiff_t msg_offset
= (char *) b
->msg
- (char *) b
->data
;
278 b
->msg
= (char *) new_data
+ msg_offset
;
284 /* Ensures that 'b' has room for at least 'size' bytes at its tail end,
285 * reallocating and copying its data if necessary. Its headroom, if any, is
288 ofpbuf_prealloc_tailroom(struct ofpbuf
*b
, size_t size
)
290 if (size
> ofpbuf_tailroom(b
)) {
291 ofpbuf_resize__(b
, ofpbuf_headroom(b
), MAX(size
, 64));
295 /* Ensures that 'b' has room for at least 'size' bytes at its head,
296 * reallocating and copying its data if necessary. Its tailroom, if any, is
299 ofpbuf_prealloc_headroom(struct ofpbuf
*b
, size_t size
)
301 if (size
> ofpbuf_headroom(b
)) {
302 ofpbuf_resize__(b
, MAX(size
, 64), ofpbuf_tailroom(b
));
306 /* Trims the size of 'b' to fit its actual content, reducing its headroom and
307 * tailroom to 0, if any.
309 * Buffers not obtained from malloc() are not resized, since that wouldn't save
312 * Caller needs to updates 'b->header' and 'b->msg' so that they point to the
313 * same locations in the data. (If they pointed into the tailroom or headroom
314 * then they become invalid.)
318 ofpbuf_trim(struct ofpbuf
*b
)
320 if (b
->source
== OFPBUF_MALLOC
321 && (ofpbuf_headroom(b
) || ofpbuf_tailroom(b
))) {
322 ofpbuf_resize__(b
, 0, 0);
326 /* If 'b' is shorter than 'length' bytes, pads its tail out with zeros to that
329 ofpbuf_padto(struct ofpbuf
*b
, size_t length
)
331 if (b
->size
< length
) {
332 ofpbuf_put_zeros(b
, length
- b
->size
);
336 /* Shifts all of the data within the allocated space in 'b' by 'delta' bytes.
337 * For example, a 'delta' of 1 would cause each byte of data to move one byte
338 * forward (from address 'p' to 'p+1'), and a 'delta' of -1 would cause each
339 * byte to move one byte backward (from 'p' to 'p-1').
341 * If used, user must make sure the 'header' and 'msg' pointers are updated
345 ofpbuf_shift(struct ofpbuf
*b
, int delta
)
347 ovs_assert(delta
> 0 ? delta
<= ofpbuf_tailroom(b
)
348 : delta
< 0 ? -delta
<= ofpbuf_headroom(b
)
352 char *dst
= (char *) b
->data
+ delta
;
353 memmove(dst
, b
->data
, b
->size
);
358 /* Appends 'size' bytes of data to the tail end of 'b', reallocating and
359 * copying its data if necessary. Returns a pointer to the first byte of the
360 * new data, which is left uninitialized. */
362 ofpbuf_put_uninit(struct ofpbuf
*b
, size_t size
)
365 ofpbuf_prealloc_tailroom(b
, size
);
371 /* Appends 'size' zeroed bytes to the tail end of 'b'. Data in 'b' is
372 * reallocated and copied if necessary. Returns a pointer to the first byte of
373 * the data's location in the ofpbuf. */
375 ofpbuf_put_zeros(struct ofpbuf
*b
, size_t size
)
377 void *dst
= ofpbuf_put_uninit(b
, size
);
378 nullable_memset(dst
, 0, size
);
382 /* Appends the 'size' bytes of data in 'p' to the tail end of 'b'. Data in 'b'
383 * is reallocated and copied if necessary. Returns a pointer to the first
384 * byte of the data's location in the ofpbuf. */
386 ofpbuf_put(struct ofpbuf
*b
, const void *p
, size_t size
)
388 void *dst
= ofpbuf_put_uninit(b
, size
);
389 memcpy(dst
, p
, size
);
393 /* Parses as many pairs of hex digits as possible (possibly separated by spaces
394 * or periods) from the beginning of 's', appending bytes for their values to
395 * 'b'. Returns the first character of 's' that is not the first of a pair of
396 * hex digits. If 'n' is nonnull, stores the number of bytes added to 'b' in
399 ofpbuf_put_hex(struct ofpbuf
*b
, const char *s
, size_t *n
)
401 size_t initial_size
= b
->size
;
406 s
+= strspn(s
, " .\t\r\n");
407 byte
= hexits_value(s
, 2, &ok
);
410 *n
= b
->size
- initial_size
;
412 return CONST_CAST(char *, s
);
415 ofpbuf_put(b
, &byte
, 1);
420 /* Reserves 'size' bytes of headroom so that they can be later allocated with
421 * ofpbuf_push_uninit() without reallocating the ofpbuf. */
423 ofpbuf_reserve(struct ofpbuf
*b
, size_t size
)
425 ovs_assert(!b
->size
);
426 ofpbuf_prealloc_tailroom(b
, size
);
427 b
->data
= (char*)b
->data
+ size
;
430 /* Prefixes 'size' bytes to the head end of 'b', reallocating and copying its
431 * data if necessary. Returns a pointer to the first byte of the data's
432 * location in the ofpbuf. The new data is left uninitialized. */
434 ofpbuf_push_uninit(struct ofpbuf
*b
, size_t size
)
436 ofpbuf_prealloc_headroom(b
, size
);
437 b
->data
= (char*)b
->data
- size
;
442 /* Prefixes 'size' zeroed bytes to the head end of 'b', reallocating and
443 * copying its data if necessary. Returns a pointer to the first byte of the
444 * data's location in the ofpbuf. */
446 ofpbuf_push_zeros(struct ofpbuf
*b
, size_t size
)
448 void *dst
= ofpbuf_push_uninit(b
, size
);
449 memset(dst
, 0, size
);
453 /* Copies the 'size' bytes starting at 'p' to the head end of 'b', reallocating
454 * and copying its data if necessary. Returns a pointer to the first byte of
455 * the data's location in the ofpbuf. */
457 ofpbuf_push(struct ofpbuf
*b
, const void *p
, size_t size
)
459 void *dst
= ofpbuf_push_uninit(b
, size
);
460 memcpy(dst
, p
, size
);
464 /* Returns the data in 'b' as a block of malloc()'d memory and frees the buffer
465 * within 'b'. (If 'b' itself was dynamically allocated, e.g. with
466 * ofpbuf_new(), then it should still be freed with, e.g., ofpbuf_delete().) */
468 ofpbuf_steal_data(struct ofpbuf
*b
)
472 if (b
->source
== OFPBUF_MALLOC
&& b
->data
== b
->base
) {
475 p
= xmemdup(b
->data
, b
->size
);
476 if (b
->source
== OFPBUF_MALLOC
) {
487 /* Returns a string that describes some of 'b''s metadata plus a hex dump of up
488 * to 'maxbytes' from the start of the buffer. */
490 ofpbuf_to_string(const struct ofpbuf
*b
, size_t maxbytes
)
495 ds_put_format(&s
, "size=%"PRIu32
", allocated=%"PRIu32
", head=%"PRIuSIZE
", tail=%"PRIuSIZE
"\n",
496 b
->size
, b
->allocated
,
497 ofpbuf_headroom(b
), ofpbuf_tailroom(b
));
498 ds_put_hex_dump(&s
, b
->data
, MIN(b
->size
, maxbytes
), 0, false);
502 /* Removes each of the "struct ofpbuf"s on 'list' from the list and frees
505 ofpbuf_list_delete(struct ovs_list
*list
)
509 LIST_FOR_EACH_POP (b
, list_node
, list
) {