3 * Packet buffer management
\r
5 * Packets are built from the pbuf data structure. It supports dynamic
\r
6 * memory allocation for packet contents or can reference externally
\r
7 * managed packet contents both in RAM and ROM. Quick allocation for
\r
8 * incoming packets is provided through pools with fixed sized pbufs.
\r
10 * A packet may span over multiple pbufs, chained as a singly linked
\r
11 * list. This is called a "pbuf chain".
\r
13 * Multiple packets may be queued, also using this singly linked list.
\r
14 * This is called a "packet queue".
\r
16 * So, a packet queue consists of one or more pbuf chains, each of
\r
17 * which consist of one or more pbufs. Currently, queues are only
\r
18 * supported in a limited section of lwIP, this is the etharp queueing
\r
19 * code. Outside of this section no packet queues are supported yet.
\r
21 * The differences between a pbuf chain and a packet queue are very
\r
22 * precise but subtle.
\r
24 * The last pbuf of a packet has a ->tot_len field that equals the
\r
25 * ->len field. It can be found by traversing the list. If the last
\r
26 * pbuf of a packet has a ->next field other than NULL, more packets
\r
29 * Therefore, looping through a pbuf of a single packet, has an
\r
30 * loop end condition (tot_len == p->len), NOT (next == NULL).
\r
34 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
\r
35 * All rights reserved.
\r
37 * Redistribution and use in source and binary forms, with or without modification,
\r
38 * are permitted provided that the following conditions are met:
\r
40 * 1. Redistributions of source code must retain the above copyright notice,
\r
41 * this list of conditions and the following disclaimer.
\r
42 * 2. Redistributions in binary form must reproduce the above copyright notice,
\r
43 * this list of conditions and the following disclaimer in the documentation
\r
44 * and/or other materials provided with the distribution.
\r
45 * 3. The name of the author may not be used to endorse or promote products
\r
46 * derived from this software without specific prior written permission.
\r
48 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
\r
49 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
\r
50 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
\r
51 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
\r
52 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
\r
53 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
\r
54 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
\r
55 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
\r
56 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
\r
59 * This file is part of the lwIP TCP/IP stack.
\r
61 * Author: Adam Dunkels <adam@sics.se>
\r
65 #include "lwip/opt.h"
\r
67 #include "lwip/stats.h"
\r
69 #include "lwip/def.h"
\r
70 #include "lwip/mem.h"
\r
71 #include "lwip/memp.h"
\r
72 #include "lwip/pbuf.h"
\r
74 #include "lwip/sys.h"
\r
76 #include "arch/perf.h"
\r
80 static u8_t pbuf_pool_memory[(PBUF_POOL_SIZE * MEM_ALIGN_SIZE(PBUF_POOL_BUFSIZE + sizeof(struct pbuf)))];
\r
82 #if !SYS_LIGHTWEIGHT_PROT
\r
83 static volatile u8_t pbuf_pool_free_lock, pbuf_pool_alloc_lock;
\r
84 static sys_sem_t pbuf_pool_free_sem;
\r
87 static struct pbuf *pbuf_pool = NULL;
\r
90 * Initializes the pbuf module.
\r
92 * A large part of memory is allocated for holding the pool of pbufs.
\r
93 * The size of the individual pbufs in the pool is given by the size
\r
94 * parameter, and the number of pbufs in the pool by the num parameter.
\r
96 * After the memory has been allocated, the pbufs are set up. The
\r
97 * ->next pointer in each pbuf is set up to point to the next pbuf in
\r
104 struct pbuf *p, *q = NULL;
\r
107 pbuf_pool = (struct pbuf *)&pbuf_pool_memory[0];
\r
108 LWIP_ASSERT("pbuf_init: pool aligned", (mem_ptr_t)pbuf_pool % MEM_ALIGNMENT == 0);
\r
111 lwip_stats.pbuf.avail = PBUF_POOL_SIZE;
\r
112 #endif /* PBUF_STATS */
\r
114 /* Set up ->next pointers to link the pbufs of the pool together */
\r
117 for(i = 0; i < PBUF_POOL_SIZE; ++i) {
\r
118 p->next = (struct pbuf *)((u8_t *)p + PBUF_POOL_BUFSIZE + sizeof(struct pbuf));
\r
119 p->len = p->tot_len = PBUF_POOL_BUFSIZE;
\r
120 p->payload = MEM_ALIGN((void *)((u8_t *)p + sizeof(struct pbuf)));
\r
121 p->flags = PBUF_FLAG_POOL;
\r
126 /* The ->next pointer of last pbuf is NULL to indicate that there
\r
127 are no more pbufs in the pool */
\r
130 #if !SYS_LIGHTWEIGHT_PROT
\r
131 pbuf_pool_alloc_lock = 0;
\r
132 pbuf_pool_free_lock = 0;
\r
133 pbuf_pool_free_sem = sys_sem_new(1);
\r
138 * @internal only called from pbuf_alloc()
\r
140 static struct pbuf *
\r
141 pbuf_pool_alloc(void)
\r
143 struct pbuf *p = NULL;
\r
145 SYS_ARCH_DECL_PROTECT(old_level);
\r
146 SYS_ARCH_PROTECT(old_level);
\r
148 #if !SYS_LIGHTWEIGHT_PROT
\r
149 /* Next, check the actual pbuf pool, but if the pool is locked, we
\r
150 pretend to be out of buffers and return NULL. */
\r
151 if (pbuf_pool_free_lock) {
\r
153 ++lwip_stats.pbuf.alloc_locked;
\r
154 #endif /* PBUF_STATS */
\r
157 pbuf_pool_alloc_lock = 1;
\r
158 if (!pbuf_pool_free_lock) {
\r
159 #endif /* SYS_LIGHTWEIGHT_PROT */
\r
162 pbuf_pool = p->next;
\r
164 #if !SYS_LIGHTWEIGHT_PROT
\r
167 ++lwip_stats.pbuf.alloc_locked;
\r
168 #endif /* PBUF_STATS */
\r
170 pbuf_pool_alloc_lock = 0;
\r
171 #endif /* SYS_LIGHTWEIGHT_PROT */
\r
175 ++lwip_stats.pbuf.used;
\r
176 if (lwip_stats.pbuf.used > lwip_stats.pbuf.max) {
\r
177 lwip_stats.pbuf.max = lwip_stats.pbuf.used;
\r
180 #endif /* PBUF_STATS */
\r
182 SYS_ARCH_UNPROTECT(old_level);
\r
188 * Allocates a pbuf of the given type (possibly a chain for PBUF_POOL type).
\r
190 * The actual memory allocated for the pbuf is determined by the
\r
191 * layer at which the pbuf is allocated and the requested size
\r
192 * (from the size parameter).
\r
194 * @param flag this parameter decides how and where the pbuf
\r
195 * should be allocated as follows:
\r
197 * - PBUF_RAM: buffer memory for pbuf is allocated as one large
\r
198 * chunk. This includes protocol headers as well.
\r
199 * - PBUF_ROM: no buffer memory is allocated for the pbuf, even for
\r
200 * protocol headers. Additional headers must be prepended
\r
201 * by allocating another pbuf and chain in to the front of
\r
202 * the ROM pbuf. It is assumed that the memory used is really
\r
203 * similar to ROM in that it is immutable and will not be
\r
204 * changed. Memory which is dynamic should generally not
\r
205 * be attached to PBUF_ROM pbufs. Use PBUF_REF instead.
\r
206 * - PBUF_REF: no buffer memory is allocated for the pbuf, even for
\r
207 * protocol headers. It is assumed that the pbuf is only
\r
208 * being used in a single thread. If the pbuf gets queued,
\r
209 * then pbuf_take should be called to copy the buffer.
\r
210 * - PBUF_POOL: the pbuf is allocated as a pbuf chain, with pbufs from
\r
211 * the pbuf pool that is allocated during pbuf_init().
\r
213 * @return the allocated pbuf. If multiple pbufs where allocated, this
\r
214 * is the first pbuf of a pbuf chain.
\r
217 pbuf_alloc(pbuf_layer l, u16_t length, pbuf_flag flag)
\r
219 struct pbuf *p, *q, *r;
\r
221 s32_t rem_len; /* remaining length */
\r
222 LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 3, ("pbuf_alloc(length=%u)\n", length));
\r
224 /* determine header offset */
\r
227 case PBUF_TRANSPORT:
\r
228 /* add room for transport (often TCP) layer header */
\r
229 offset += PBUF_TRANSPORT_HLEN;
\r
232 /* add room for IP layer header */
\r
233 offset += PBUF_IP_HLEN;
\r
236 /* add room for link layer header */
\r
237 offset += PBUF_LINK_HLEN;
\r
242 LWIP_ASSERT("pbuf_alloc: bad pbuf layer", 0);
\r
248 /* allocate head of pbuf chain into p */
\r
249 p = pbuf_pool_alloc();
\r
250 LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 3, ("pbuf_alloc: allocated pbuf %p\n", (void *)p));
\r
253 ++lwip_stats.pbuf.err;
\r
254 #endif /* PBUF_STATS */
\r
259 /* make the payload pointer point 'offset' bytes into pbuf data memory */
\r
260 p->payload = MEM_ALIGN((void *)((u8_t *)p + (sizeof(struct pbuf) + offset)));
\r
261 LWIP_ASSERT("pbuf_alloc: pbuf p->payload properly aligned",
\r
262 ((mem_ptr_t)p->payload % MEM_ALIGNMENT) == 0);
\r
263 /* the total length of the pbuf chain is the requested size */
\r
264 p->tot_len = length;
\r
265 /* set the length of the first pbuf in the chain */
\r
266 p->len = length > PBUF_POOL_BUFSIZE - offset? PBUF_POOL_BUFSIZE - offset: length;
\r
267 /* set reference count (needed here in case we fail) */
\r
270 /* now allocate the tail of the pbuf chain */
\r
272 /* remember first pbuf for linkage in next iteration */
\r
274 /* remaining length to be allocated */
\r
275 rem_len = length - p->len;
\r
276 /* any remaining pbufs to be allocated? */
\r
277 while (rem_len > 0) {
\r
278 q = pbuf_pool_alloc();
\r
280 LWIP_DEBUGF(PBUF_DEBUG | 2, ("pbuf_alloc: Out of pbufs in pool.\n"));
\r
282 ++lwip_stats.pbuf.err;
\r
283 #endif /* PBUF_STATS */
\r
284 /* free chain so far allocated */
\r
286 /* bail out unsuccesfully */
\r
290 /* make previous pbuf point to this pbuf */
\r
292 /* set total length of this pbuf and next in chain */
\r
293 q->tot_len = rem_len;
\r
294 /* this pbuf length is pool size, unless smaller sized tail */
\r
295 q->len = rem_len > PBUF_POOL_BUFSIZE? PBUF_POOL_BUFSIZE: rem_len;
\r
296 q->payload = (void *)((u8_t *)q + sizeof(struct pbuf));
\r
297 LWIP_ASSERT("pbuf_alloc: pbuf q->payload properly aligned",
\r
298 ((mem_ptr_t)q->payload % MEM_ALIGNMENT) == 0);
\r
300 /* calculate remaining length to be allocated */
\r
302 /* remember this pbuf for linkage in next iteration */
\r
306 /*r->next = NULL;*/
\r
310 /* If pbuf is to be allocated in RAM, allocate memory for it. */
\r
311 p = mem_malloc(MEM_ALIGN_SIZE(sizeof(struct pbuf) + offset) + MEM_ALIGN_SIZE(length));
\r
315 /* Set up internal structure of the pbuf. */
\r
316 p->payload = MEM_ALIGN((void *)((u8_t *)p + sizeof(struct pbuf) + offset));
\r
317 p->len = p->tot_len = length;
\r
319 p->flags = PBUF_FLAG_RAM;
\r
321 LWIP_ASSERT("pbuf_alloc: pbuf->payload properly aligned",
\r
322 ((mem_ptr_t)p->payload % MEM_ALIGNMENT) == 0);
\r
324 /* pbuf references existing (non-volatile static constant) ROM payload? */
\r
326 /* pbuf references existing (externally allocated) RAM payload? */
\r
328 /* only allocate memory for the pbuf structure */
\r
329 p = memp_malloc(MEMP_PBUF);
\r
331 LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 2, ("pbuf_alloc: Could not allocate MEMP_PBUF for PBUF_%s.\n", flag == PBUF_ROM?"ROM":"REF"));
\r
334 /* caller must set this field properly, afterwards */
\r
336 p->len = p->tot_len = length;
\r
338 p->flags = (flag == PBUF_ROM? PBUF_FLAG_ROM: PBUF_FLAG_REF);
\r
341 LWIP_ASSERT("pbuf_alloc: erroneous flag", 0);
\r
344 /* set reference count */
\r
346 LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 3, ("pbuf_alloc(length=%u) == %p\n", length, (void *)p));
\r
352 #define DEC_PBUF_STATS do { --lwip_stats.pbuf.used; } while (0)
\r
353 #else /* PBUF_STATS */
\r
354 #define DEC_PBUF_STATS
\r
355 #endif /* PBUF_STATS */
\r
357 #define PBUF_POOL_FAST_FREE(p) do { \
\r
358 p->next = pbuf_pool; \
\r
363 #if SYS_LIGHTWEIGHT_PROT
\r
364 #define PBUF_POOL_FREE(p) do { \
\r
365 SYS_ARCH_DECL_PROTECT(old_level); \
\r
366 SYS_ARCH_PROTECT(old_level); \
\r
367 PBUF_POOL_FAST_FREE(p); \
\r
368 SYS_ARCH_UNPROTECT(old_level); \
\r
370 #else /* SYS_LIGHTWEIGHT_PROT */
\r
371 #define PBUF_POOL_FREE(p) do { \
\r
372 sys_sem_wait(pbuf_pool_free_sem); \
\r
373 PBUF_POOL_FAST_FREE(p); \
\r
374 sys_sem_signal(pbuf_pool_free_sem); \
\r
376 #endif /* SYS_LIGHTWEIGHT_PROT */
\r
379 * Shrink a pbuf chain to a desired length.
\r
381 * @param p pbuf to shrink.
\r
382 * @param new_len desired new length of pbuf chain
\r
384 * Depending on the desired length, the first few pbufs in a chain might
\r
385 * be skipped and left unchanged. The new last pbuf in the chain will be
\r
386 * resized, and any remaining pbufs will be freed.
\r
388 * @note If the pbuf is ROM/REF, only the ->tot_len and ->len fields are adjusted.
\r
389 * @note May not be called on a packet queue.
\r
391 * @bug Cannot grow the size of a pbuf (chain) (yet).
\r
394 pbuf_realloc(struct pbuf *p, u16_t new_len)
\r
397 u16_t rem_len; /* remaining length */
\r
400 LWIP_ASSERT("pbuf_realloc: sane p->flags", p->flags == PBUF_FLAG_POOL ||
\r
401 p->flags == PBUF_FLAG_ROM ||
\r
402 p->flags == PBUF_FLAG_RAM ||
\r
403 p->flags == PBUF_FLAG_REF);
\r
405 /* desired length larger than current length? */
\r
406 if (new_len >= p->tot_len) {
\r
407 /* enlarging not yet supported */
\r
411 /* the pbuf chain grows by (new_len - p->tot_len) bytes
\r
412 * (which may be negative in case of shrinking) */
\r
413 grow = new_len - p->tot_len;
\r
415 /* first, step over any pbufs that should remain in the chain */
\r
418 /* should this pbuf be kept? */
\r
419 while (rem_len > q->len) {
\r
420 /* decrease remaining length by pbuf length */
\r
422 /* decrease total length indicator */
\r
423 q->tot_len += grow;
\r
424 /* proceed to next pbuf in chain */
\r
427 /* we have now reached the new last pbuf (in q) */
\r
428 /* rem_len == desired length for pbuf q */
\r
430 /* shrink allocated memory for PBUF_RAM */
\r
431 /* (other types merely adjust their length fields */
\r
432 if ((q->flags == PBUF_FLAG_RAM) && (rem_len != q->len)) {
\r
433 /* reallocate and adjust the length of the pbuf that will be split */
\r
434 mem_realloc(q, (u8_t *)q->payload - (u8_t *)q + rem_len);
\r
436 /* adjust length fields for new last pbuf */
\r
438 q->tot_len = q->len;
\r
440 /* any remaining pbufs in chain? */
\r
441 if (q->next != NULL) {
\r
442 /* free remaining pbufs in chain */
\r
443 pbuf_free(q->next);
\r
445 /* q is last packet in chain */
\r
451 * Adjusts the payload pointer to hide or reveal headers in the payload.
\r
453 * Adjusts the ->payload pointer so that space for a header
\r
454 * (dis)appears in the pbuf payload.
\r
456 * The ->payload, ->tot_len and ->len fields are adjusted.
\r
458 * @param hdr_size_inc Number of bytes to increment header size which
\r
459 * increases the size of the pbuf. New space is on the front.
\r
460 * (Using a negative value decreases the header size.)
\r
461 * If hdr_size_inc is 0, this function does nothing and returns succesful.
\r
463 * PBUF_ROM and PBUF_REF type buffers cannot have their sizes increased, so
\r
464 * the call will fail. A check is made that the increase in header size does
\r
465 * not move the payload pointer in front of the start of the buffer.
\r
466 * @return non-zero on failure, zero on success.
\r
470 pbuf_header(struct pbuf *p, s16_t header_size_increment)
\r
474 LWIP_ASSERT("p != NULL", p != NULL);
\r
475 if ((header_size_increment == 0) || (p == NULL)) return 0;
\r
477 /* remember current payload pointer */
\r
478 payload = p->payload;
\r
480 /* pbuf types containing payloads? */
\r
481 if (p->flags == PBUF_FLAG_RAM || p->flags == PBUF_FLAG_POOL) {
\r
482 /* set new payload pointer */
\r
483 p->payload = (u8_t *)p->payload - header_size_increment;
\r
484 /* boundary check fails? */
\r
485 if ((u8_t *)p->payload < (u8_t *)p + sizeof(struct pbuf)) {
\r
486 LWIP_DEBUGF( PBUF_DEBUG | 2, ("pbuf_header: failed as %p < %p (not enough space for new header size)\n",
\r
487 (void *)p->payload,
\r
488 (void *)(p + 1)));\
\r
489 /* restore old payload pointer */
\r
490 p->payload = payload;
\r
491 /* bail out unsuccesfully */
\r
494 /* pbuf types refering to external payloads? */
\r
495 } else if (p->flags == PBUF_FLAG_REF || p->flags == PBUF_FLAG_ROM) {
\r
496 /* hide a header in the payload? */
\r
497 if ((header_size_increment < 0) && (header_size_increment - p->len <= 0)) {
\r
498 /* increase payload pointer */
\r
499 p->payload = (u8_t *)p->payload - header_size_increment;
\r
501 /* cannot expand payload to front (yet!)
\r
502 * bail out unsuccesfully */
\r
506 /* modify pbuf length fields */
\r
507 p->len += header_size_increment;
\r
508 p->tot_len += header_size_increment;
\r
510 LWIP_DEBUGF( PBUF_DEBUG, ("pbuf_header: old %p new %p (%d)\n",
\r
511 (void *)payload, (void *)p->payload, header_size_increment));
\r
517 * Dereference a pbuf chain or queue and deallocate any no-longer-used
\r
518 * pbufs at the head of this chain or queue.
\r
520 * Decrements the pbuf reference count. If it reaches zero, the pbuf is
\r
523 * For a pbuf chain, this is repeated for each pbuf in the chain,
\r
524 * up to the first pbuf which has a non-zero reference count after
\r
525 * decrementing. So, when all reference counts are one, the whole
\r
528 * @param pbuf The pbuf (chain) to be dereferenced.
\r
530 * @return the number of pbufs that were de-allocated
\r
531 * from the head of the chain.
\r
533 * @note MUST NOT be called on a packet queue (Not verified to work yet).
\r
534 * @note the reference counter of a pbuf equals the number of pointers
\r
535 * that refer to the pbuf (or into the pbuf).
\r
537 * @internal examples:
\r
539 * Assuming existing chains a->b->c with the following reference
\r
540 * counts, calling pbuf_free(a) results in:
\r
542 * 1->2->3 becomes ...1->3
\r
543 * 3->3->3 becomes 2->3->3
\r
544 * 1->1->2 becomes ......1
\r
545 * 2->1->1 becomes 1->1->1
\r
546 * 1->1->1 becomes .......
\r
550 pbuf_free(struct pbuf *p)
\r
554 SYS_ARCH_DECL_PROTECT(old_level);
\r
556 LWIP_ASSERT("p != NULL", p != NULL);
\r
557 /* if assertions are disabled, proceed with debug output */
\r
559 LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 2, ("pbuf_free(p == NULL) was called.\n"));
\r
562 LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 3, ("pbuf_free(%p)\n", (void *)p));
\r
566 LWIP_ASSERT("pbuf_free: sane flags",
\r
567 p->flags == PBUF_FLAG_RAM || p->flags == PBUF_FLAG_ROM ||
\r
568 p->flags == PBUF_FLAG_REF || p->flags == PBUF_FLAG_POOL);
\r
571 /* Since decrementing ref cannot be guaranteed to be a single machine operation
\r
572 * we must protect it. Also, the later test of ref must be protected.
\r
574 SYS_ARCH_PROTECT(old_level);
\r
575 /* de-allocate all consecutive pbufs from the head of the chain that
\r
576 * obtain a zero reference count after decrementing*/
\r
577 while (p != NULL) {
\r
578 /* all pbufs in a chain are referenced at least once */
\r
579 LWIP_ASSERT("pbuf_free: p->ref > 0", p->ref > 0);
\r
580 /* decrease reference count (number of pointers to pbuf) */
\r
582 /* this pbuf is no longer referenced to? */
\r
584 /* remember next pbuf in chain for next iteration */
\r
586 LWIP_DEBUGF( PBUF_DEBUG | 2, ("pbuf_free: deallocating %p\n", (void *)p));
\r
587 /* is this a pbuf from the pool? */
\r
588 if (p->flags == PBUF_FLAG_POOL) {
\r
589 p->len = p->tot_len = PBUF_POOL_BUFSIZE;
\r
590 p->payload = (void *)((u8_t *)p + sizeof(struct pbuf));
\r
592 /* is this a ROM or RAM referencing pbuf? */
\r
593 } else if (p->flags == PBUF_FLAG_ROM || p->flags == PBUF_FLAG_REF) {
\r
594 memp_free(MEMP_PBUF, p);
\r
595 /* p->flags == PBUF_FLAG_RAM */
\r
600 /* proceed to next pbuf */
\r
602 /* p->ref > 0, this pbuf is still referenced to */
\r
603 /* (and so the remaining pbufs in chain as well) */
\r
605 LWIP_DEBUGF( PBUF_DEBUG | 2, ("pbuf_free: %p has ref %u, ending here.\n", (void *)p, (unsigned int)p->ref));
\r
606 /* stop walking through the chain */
\r
610 SYS_ARCH_UNPROTECT(old_level);
\r
611 PERF_STOP("pbuf_free");
\r
612 /* return number of de-allocated pbufs */
\r
617 * Count number of pbufs in a chain
\r
619 * @param p first pbuf of chain
\r
620 * @return the number of pbufs in a chain
\r
624 pbuf_clen(struct pbuf *p)
\r
629 while (p != NULL) {
\r
637 * Increment the reference count of the pbuf.
\r
639 * @param p pbuf to increase reference counter of
\r
643 pbuf_ref(struct pbuf *p)
\r
645 SYS_ARCH_DECL_PROTECT(old_level);
\r
648 SYS_ARCH_PROTECT(old_level);
\r
650 SYS_ARCH_UNPROTECT(old_level);
\r
655 * Concatenate two pbufs (each may be a pbuf chain) and take over
\r
656 * the caller's reference of the tail pbuf.
\r
658 * @note The caller MAY NOT reference the tail pbuf afterwards.
\r
659 * Use pbuf_chain() for that purpose.
\r
661 * @see pbuf_chain()
\r
665 pbuf_cat(struct pbuf *h, struct pbuf *t)
\r
669 LWIP_ASSERT("h != NULL (programmer violates API)", h != NULL);
\r
670 LWIP_ASSERT("t != NULL (programmer violates API)", t != NULL);
\r
671 if ((h == NULL) || (t == NULL)) return;
\r
673 /* proceed to last pbuf of chain */
\r
674 for (p = h; p->next != NULL; p = p->next) {
\r
675 /* add total length of second chain to all totals of first chain */
\r
676 p->tot_len += t->tot_len;
\r
678 /* { p is last pbuf of first h chain, p->next == NULL } */
\r
679 LWIP_ASSERT("p->tot_len == p->len (of last pbuf in chain)", p->tot_len == p->len);
\r
680 LWIP_ASSERT("p->next == NULL", p->next == NULL);
\r
681 /* add total length of second chain to last pbuf total of first chain */
\r
682 p->tot_len += t->tot_len;
\r
683 /* chain last pbuf of head (p) with first of tail (t) */
\r
685 /* p->next now references t, but the caller will drop its reference to t,
\r
686 * so netto there is no change to the reference count of t.
\r
691 * Chain two pbufs (or pbuf chains) together.
\r
693 * The caller MUST call pbuf_free(t) once it has stopped
\r
694 * using it. Use pbuf_cat() instead if you no longer use t.
\r
696 * @param h head pbuf (chain)
\r
697 * @param t tail pbuf (chain)
\r
698 * @note The pbufs MUST belong to the same packet.
\r
699 * @note MAY NOT be called on a packet queue.
\r
701 * The ->tot_len fields of all pbufs of the head chain are adjusted.
\r
702 * The ->next field of the last pbuf of the head chain is adjusted.
\r
703 * The ->ref field of the first pbuf of the tail chain is adjusted.
\r
707 pbuf_chain(struct pbuf *h, struct pbuf *t)
\r
710 /* t is now referenced by h */
\r
712 LWIP_DEBUGF(PBUF_DEBUG | DBG_FRESH | 2, ("pbuf_chain: %p references %p\n", (void *)h, (void *)t));
\r
715 /* For packet queueing. Note that queued packets MUST be dequeued first
\r
716 * using pbuf_dequeue() before calling other pbuf_() functions. */
\r
719 * Add a packet to the end of a queue.
\r
721 * @param q pointer to first packet on the queue
\r
722 * @param n packet to be queued
\r
724 * Both packets MUST be given, and must be different.
\r
727 pbuf_queue(struct pbuf *p, struct pbuf *n)
\r
729 #if PBUF_DEBUG /* remember head of queue */
\r
730 struct pbuf *q = p;
\r
732 /* programmer stupidity checks */
\r
733 LWIP_ASSERT("p == NULL in pbuf_queue: this indicates a programmer error\n", p != NULL);
\r
734 LWIP_ASSERT("n == NULL in pbuf_queue: this indicates a programmer error\n", n != NULL);
\r
735 LWIP_ASSERT("p == n in pbuf_queue: this indicates a programmer error\n", p != n);
\r
736 if ((p == NULL) || (n == NULL) || (p == n)){
\r
737 LWIP_DEBUGF(PBUF_DEBUG | DBG_HALT | 3, ("pbuf_queue: programmer argument error\n"))
\r
741 /* iterate through all packets on queue */
\r
742 while (p->next != NULL) {
\r
743 /* be very picky about pbuf chain correctness */
\r
745 /* iterate through all pbufs in packet */
\r
746 while (p->tot_len != p->len) {
\r
747 /* make sure invariant condition holds */
\r
748 LWIP_ASSERT("p->len < p->tot_len", p->len < p->tot_len);
\r
749 /* make sure each packet is complete */
\r
750 LWIP_ASSERT("p->next != NULL", p->next != NULL);
\r
752 /* { p->tot_len == p->len => p is last pbuf of a packet } */
\r
754 /* { p is last pbuf of a packet } */
\r
755 /* proceed to next packet on queue */
\r
757 /* proceed to next pbuf */
\r
758 if (p->next != NULL) p = p->next;
\r
760 /* { p->tot_len == p->len and p->next == NULL } ==>
\r
761 * { p is last pbuf of last packet on queue } */
\r
762 /* chain last pbuf of queue with n */
\r
764 /* n is now referenced to by the (packet p in the) queue */
\r
767 LWIP_DEBUGF(PBUF_DEBUG | DBG_FRESH | 2,
\r
768 ("pbuf_queue: newly queued packet %p sits after packet %p in queue %p\n",
\r
769 (void *)n, (void *)p, (void *)q));
\r
774 * Remove a packet from the head of a queue.
\r
776 * The caller MUST reference the remainder of the queue (as returned). The
\r
777 * caller MUST NOT call pbuf_ref() as it implicitly takes over the reference
\r
780 * @param p pointer to first packet on the queue which will be dequeued.
\r
781 * @return first packet on the remaining queue (NULL if no further packets).
\r
785 pbuf_dequeue(struct pbuf *p)
\r
788 LWIP_ASSERT("p != NULL", p != NULL);
\r
790 /* iterate through all pbufs in packet p */
\r
791 while (p->tot_len != p->len) {
\r
792 /* make sure invariant condition holds */
\r
793 LWIP_ASSERT("p->len < p->tot_len", p->len < p->tot_len);
\r
794 /* make sure each packet is complete */
\r
795 LWIP_ASSERT("p->next != NULL", p->next != NULL);
\r
798 /* { p->tot_len == p->len } => p is the last pbuf of the first packet */
\r
799 /* remember next packet on queue in q */
\r
801 /* dequeue packet p from queue */
\r
803 /* any next packet on queue? */
\r
805 /* although q is no longer referenced by p, it MUST be referenced by
\r
806 * the caller, who is maintaining this packet queue. So, we do not call
\r
807 * pbuf_free(q) here, resulting in an implicit pbuf_ref(q) for the caller. */
\r
808 LWIP_DEBUGF(PBUF_DEBUG | DBG_FRESH | 2, ("pbuf_dequeue: first remaining packet on queue is %p\n", (void *)q));
\r
810 LWIP_DEBUGF(PBUF_DEBUG | DBG_FRESH | 2, ("pbuf_dequeue: no further packets on queue\n"));
\r
818 * Create PBUF_POOL (or PBUF_RAM) copies of PBUF_REF pbufs.
\r
820 * Used to queue packets on behalf of the lwIP stack, such as
\r
821 * ARP based queueing.
\r
823 * Go through a pbuf chain and replace any PBUF_REF buffers
\r
824 * with PBUF_POOL (or PBUF_RAM) pbufs, each taking a copy of
\r
825 * the referenced data.
\r
827 * @note You MUST explicitly use p = pbuf_take(p);
\r
828 * The pbuf you give as argument, may have been replaced
\r
829 * by a (differently located) copy through pbuf_take()!
\r
831 * @note Any replaced pbufs will be freed through pbuf_free().
\r
832 * This may deallocate them if they become no longer referenced.
\r
834 * @param p Head of pbuf chain to process
\r
836 * @return Pointer to head of pbuf chain
\r
839 pbuf_take(struct pbuf *p)
\r
841 struct pbuf *q , *prev, *head;
\r
842 LWIP_ASSERT("pbuf_take: p != NULL\n", p != NULL);
\r
843 LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 3, ("pbuf_take(%p)\n", (void*)p));
\r
847 /* iterate through pbuf chain */
\r
850 /* pbuf is of type PBUF_REF? */
\r
851 if (p->flags == PBUF_FLAG_REF) {
\r
852 LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE, ("pbuf_take: encountered PBUF_REF %p\n", (void *)p));
\r
853 /* allocate a pbuf (w/ payload) fully in RAM */
\r
854 /* PBUF_POOL buffers are faster if we can use them */
\r
855 if (p->len <= PBUF_POOL_BUFSIZE) {
\r
856 q = pbuf_alloc(PBUF_RAW, p->len, PBUF_POOL);
\r
858 LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 2, ("pbuf_take: Could not allocate PBUF_POOL\n"));
\r
861 /* no replacement pbuf yet */
\r
863 LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 2, ("pbuf_take: PBUF_POOL too small to replace PBUF_REF\n"));
\r
865 /* no (large enough) PBUF_POOL was available? retry with PBUF_RAM */
\r
867 q = pbuf_alloc(PBUF_RAW, p->len, PBUF_RAM);
\r
869 LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 2, ("pbuf_take: Could not allocate PBUF_RAM\n"));
\r
872 /* replacement pbuf could be allocated? */
\r
876 /* copy successor */
\r
878 /* remove linkage from original pbuf */
\r
880 /* remove linkage to original pbuf */
\r
881 if (prev != NULL) {
\r
882 /* prev->next == p at this point */
\r
883 LWIP_ASSERT("prev->next == p", prev->next == p);
\r
884 /* break chain and insert new pbuf instead */
\r
886 /* prev == NULL, so we replaced the head pbuf of the chain */
\r
890 /* copy pbuf payload */
\r
891 memcpy(q->payload, p->payload, p->len);
\r
892 q->tot_len = p->tot_len;
\r
894 /* in case p was the first pbuf, it is no longer refered to by
\r
895 * our caller, as the caller MUST do p = pbuf_take(p);
\r
896 * in case p was not the first pbuf, it is no longer refered to
\r
897 * by prev. we can safely free the pbuf here.
\r
898 * (note that we have set p->next to NULL already so that
\r
899 * we will not free the rest of the chain by accident.)
\r
902 /* do not copy ref, since someone else might be using the old buffer */
\r
903 LWIP_DEBUGF(PBUF_DEBUG, ("pbuf_take: replaced PBUF_REF %p with %p\n", (void *)p, (void *)q));
\r
906 /* deallocate chain */
\r
908 LWIP_DEBUGF(PBUF_DEBUG | 2, ("pbuf_take: failed to allocate replacement pbuf for %p\n", (void *)p));
\r
911 /* p->flags != PBUF_FLAG_REF */
\r
913 LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 1, ("pbuf_take: skipping pbuf not of type PBUF_REF\n"));
\r
915 /* remember this pbuf */
\r
917 /* proceed to next pbuf in original chain */
\r
920 LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 1, ("pbuf_take: end of chain reached.\n"));
\r
926 * Dechains the first pbuf from its succeeding pbufs in the chain.
\r
928 * Makes p->tot_len field equal to p->len.
\r
929 * @param p pbuf to dechain
\r
930 * @return remainder of the pbuf chain, or NULL if it was de-allocated.
\r
931 * @note May not be called on a packet queue.
\r
934 pbuf_dechain(struct pbuf *p)
\r
937 u8_t tail_gone = 1;
\r
940 /* pbuf has successor in chain? */
\r
942 /* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */
\r
943 LWIP_ASSERT("p->tot_len == p->len + q->tot_len", q->tot_len == p->tot_len - p->len);
\r
944 /* enforce invariant if assertion is disabled */
\r
945 q->tot_len = p->tot_len - p->len;
\r
946 /* decouple pbuf from remainder */
\r
948 /* total length of pbuf p is its own length only */
\r
949 p->tot_len = p->len;
\r
950 /* q is no longer referenced by p, free it */
\r
951 LWIP_DEBUGF(PBUF_DEBUG | DBG_STATE, ("pbuf_dechain: unreferencing %p\n", (void *)q));
\r
952 tail_gone = pbuf_free(q);
\r
953 if (tail_gone > 0) {
\r
954 LWIP_DEBUGF(PBUF_DEBUG | DBG_STATE,
\r
955 ("pbuf_dechain: deallocated %p (as it is no longer referenced)\n", (void *)q));
\r
957 /* return remaining tail or NULL if deallocated */
\r
959 /* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */
\r
960 LWIP_ASSERT("p->tot_len == p->len", p->tot_len == p->len);
\r
961 return (tail_gone > 0? NULL: q);
\r