source: UsbWattMeter/trunk/lwip-1.4.1/src/core/pbuf.c@ 164

Last change on this file since 164 was 164, checked in by coas-nagasima, 6 years ago

TOPPERS/ECNLサンプルアプリ「USB充電器電力計」を追加

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1/**
2 * @file
3 * Packet buffer management
4 *
5 * Packets are built from the pbuf data structure. It supports dynamic
6 * memory allocation for packet contents or can reference externally
7 * managed packet contents both in RAM and ROM. Quick allocation for
8 * incoming packets is provided through pools with fixed sized pbufs.
9 *
10 * A packet may span over multiple pbufs, chained as a singly linked
11 * list. This is called a "pbuf chain".
12 *
13 * Multiple packets may be queued, also using this singly linked list.
14 * This is called a "packet queue".
15 *
16 * So, a packet queue consists of one or more pbuf chains, each of
17 * which consist of one or more pbufs. CURRENTLY, PACKET QUEUES ARE
18 * NOT SUPPORTED!!! Use helper structs to queue multiple packets.
19 *
20 * The differences between a pbuf chain and a packet queue are very
21 * precise but subtle.
22 *
23 * The last pbuf of a packet has a ->tot_len field that equals the
24 * ->len field. It can be found by traversing the list. If the last
25 * pbuf of a packet has a ->next field other than NULL, more packets
26 * are on the queue.
27 *
28 * Therefore, looping through a pbuf of a single packet, has an
29 * loop end condition (tot_len == p->len), NOT (next == NULL).
30 */
31
32/*
33 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
34 * All rights reserved.
35 *
36 * Redistribution and use in source and binary forms, with or without modification,
37 * are permitted provided that the following conditions are met:
38 *
39 * 1. Redistributions of source code must retain the above copyright notice,
40 * this list of conditions and the following disclaimer.
41 * 2. Redistributions in binary form must reproduce the above copyright notice,
42 * this list of conditions and the following disclaimer in the documentation
43 * and/or other materials provided with the distribution.
44 * 3. The name of the author may not be used to endorse or promote products
45 * derived from this software without specific prior written permission.
46 *
47 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
48 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
49 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
50 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
51 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
52 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
53 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
54 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
55 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
56 * OF SUCH DAMAGE.
57 *
58 * This file is part of the lwIP TCP/IP stack.
59 *
60 * Author: Adam Dunkels <adam@sics.se>
61 *
62 */
63
64#include "lwip/opt.h"
65
66#include "lwip/stats.h"
67#include "lwip/def.h"
68#include "lwip/mem.h"
69#include "lwip/memp.h"
70#include "lwip/pbuf.h"
71#include "lwip/sys.h"
72#include "arch/perf.h"
73#if LWIP_TCP && TCP_QUEUE_OOSEQ
74#include "lwip/tcp_impl.h"
75#endif
76#if LWIP_CHECKSUM_ON_COPY
77#include "lwip/inet_chksum.h"
78#endif
79
80#include <string.h>
81
82#define SIZEOF_STRUCT_PBUF LWIP_MEM_ALIGN_SIZE(sizeof(struct pbuf))
83/* Since the pool is created in memp, PBUF_POOL_BUFSIZE will be automatically
84 aligned there. Therefore, PBUF_POOL_BUFSIZE_ALIGNED can be used here. */
85#define PBUF_POOL_BUFSIZE_ALIGNED LWIP_MEM_ALIGN_SIZE(PBUF_POOL_BUFSIZE)
86
87#if !LWIP_TCP || !TCP_QUEUE_OOSEQ || !PBUF_POOL_FREE_OOSEQ
88#define PBUF_POOL_IS_EMPTY()
89#else /* !LWIP_TCP || !TCP_QUEUE_OOSEQ || !PBUF_POOL_FREE_OOSEQ */
90
91#if !NO_SYS
92#ifndef PBUF_POOL_FREE_OOSEQ_QUEUE_CALL
93#include "lwip/tcpip.h"
94#define PBUF_POOL_FREE_OOSEQ_QUEUE_CALL() do { \
95 if(tcpip_callback_with_block(pbuf_free_ooseq_callback, NULL, 0) != ERR_OK) { \
96 SYS_ARCH_PROTECT(old_level); \
97 pbuf_free_ooseq_pending = 0; \
98 SYS_ARCH_UNPROTECT(old_level); \
99 } } while(0)
100#endif /* PBUF_POOL_FREE_OOSEQ_QUEUE_CALL */
101#endif /* !NO_SYS */
102
103volatile u8_t pbuf_free_ooseq_pending;
104#define PBUF_POOL_IS_EMPTY() pbuf_pool_is_empty()
105
106/**
107 * Attempt to reclaim some memory from queued out-of-sequence TCP segments
108 * if we run out of pool pbufs. It's better to give priority to new packets
109 * if we're running out.
110 *
111 * This must be done in the correct thread context therefore this function
112 * can only be used with NO_SYS=0 and through tcpip_callback.
113 */
114#if !NO_SYS
115static
116#endif /* !NO_SYS */
117void
118pbuf_free_ooseq(void)
119{
120 struct tcp_pcb* pcb;
121 SYS_ARCH_DECL_PROTECT(old_level);
122
123 SYS_ARCH_PROTECT(old_level);
124 pbuf_free_ooseq_pending = 0;
125 SYS_ARCH_UNPROTECT(old_level);
126
127 for (pcb = tcp_active_pcbs; NULL != pcb; pcb = pcb->next) {
128 if (NULL != pcb->ooseq) {
129 /** Free the ooseq pbufs of one PCB only */
130 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_free_ooseq: freeing out-of-sequence pbufs\n"));
131 tcp_segs_free(pcb->ooseq);
132 pcb->ooseq = NULL;
133 return;
134 }
135 }
136}
137
138#if !NO_SYS
139/**
140 * Just a callback function for tcpip_timeout() that calls pbuf_free_ooseq().
141 */
142static void
143pbuf_free_ooseq_callback(void *arg)
144{
145 LWIP_UNUSED_ARG(arg);
146 pbuf_free_ooseq();
147}
148#endif /* !NO_SYS */
149
150/** Queue a call to pbuf_free_ooseq if not already queued. */
151static void
152pbuf_pool_is_empty(void)
153{
154#ifndef PBUF_POOL_FREE_OOSEQ_QUEUE_CALL
155 SYS_ARCH_DECL_PROTECT(old_level);
156 SYS_ARCH_PROTECT(old_level);
157 pbuf_free_ooseq_pending = 1;
158 SYS_ARCH_UNPROTECT(old_level);
159#else /* PBUF_POOL_FREE_OOSEQ_QUEUE_CALL */
160 u8_t queued;
161 SYS_ARCH_DECL_PROTECT(old_level);
162 SYS_ARCH_PROTECT(old_level);
163 queued = pbuf_free_ooseq_pending;
164 pbuf_free_ooseq_pending = 1;
165 SYS_ARCH_UNPROTECT(old_level);
166
167 if(!queued) {
168 /* queue a call to pbuf_free_ooseq if not already queued */
169 PBUF_POOL_FREE_OOSEQ_QUEUE_CALL();
170 }
171#endif /* PBUF_POOL_FREE_OOSEQ_QUEUE_CALL */
172}
173#endif /* !LWIP_TCP || !TCP_QUEUE_OOSEQ || !PBUF_POOL_FREE_OOSEQ */
174
175/**
176 * Allocates a pbuf of the given type (possibly a chain for PBUF_POOL type).
177 *
178 * The actual memory allocated for the pbuf is determined by the
179 * layer at which the pbuf is allocated and the requested size
180 * (from the size parameter).
181 *
182 * @param layer flag to define header size
183 * @param length size of the pbuf's payload
184 * @param type this parameter decides how and where the pbuf
185 * should be allocated as follows:
186 *
187 * - PBUF_RAM: buffer memory for pbuf is allocated as one large
188 * chunk. This includes protocol headers as well.
189 * - PBUF_ROM: no buffer memory is allocated for the pbuf, even for
190 * protocol headers. Additional headers must be prepended
191 * by allocating another pbuf and chain in to the front of
192 * the ROM pbuf. It is assumed that the memory used is really
193 * similar to ROM in that it is immutable and will not be
194 * changed. Memory which is dynamic should generally not
195 * be attached to PBUF_ROM pbufs. Use PBUF_REF instead.
196 * - PBUF_REF: no buffer memory is allocated for the pbuf, even for
197 * protocol headers. It is assumed that the pbuf is only
198 * being used in a single thread. If the pbuf gets queued,
199 * then pbuf_take should be called to copy the buffer.
200 * - PBUF_POOL: the pbuf is allocated as a pbuf chain, with pbufs from
201 * the pbuf pool that is allocated during pbuf_init().
202 *
203 * @return the allocated pbuf. If multiple pbufs where allocated, this
204 * is the first pbuf of a pbuf chain.
205 */
206struct pbuf *
207pbuf_alloc(pbuf_layer layer, u16_t length, pbuf_type type)
208{
209 struct pbuf *p, *q, *r;
210 u16_t offset;
211 s32_t rem_len; /* remaining length */
212 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloc(length=%"U16_F")\n", length));
213
214 /* determine header offset */
215 switch (layer) {
216 case PBUF_TRANSPORT:
217 /* add room for transport (often TCP) layer header */
218 offset = PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN;
219 break;
220 case PBUF_IP:
221 /* add room for IP layer header */
222 offset = PBUF_LINK_HLEN + PBUF_IP_HLEN;
223 break;
224 case PBUF_LINK:
225 /* add room for link layer header */
226 offset = PBUF_LINK_HLEN;
227 break;
228 case PBUF_RAW:
229 offset = 0;
230 break;
231 default:
232 LWIP_ASSERT("pbuf_alloc: bad pbuf layer", 0);
233 return NULL;
234 }
235
236 switch (type) {
237 case PBUF_POOL:
238 /* allocate head of pbuf chain into p */
239 p = (struct pbuf *)memp_malloc(MEMP_PBUF_POOL);
240 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloc: allocated pbuf %p\n", (void *)p));
241 if (p == NULL) {
242 PBUF_POOL_IS_EMPTY();
243 return NULL;
244 }
245 p->type = type;
246 p->next = NULL;
247
248 /* make the payload pointer point 'offset' bytes into pbuf data memory */
249 p->payload = LWIP_MEM_ALIGN((void *)((u8_t *)p + (SIZEOF_STRUCT_PBUF + offset)));
250 LWIP_ASSERT("pbuf_alloc: pbuf p->payload properly aligned",
251 ((mem_ptr_t)p->payload % MEM_ALIGNMENT) == 0);
252 /* the total length of the pbuf chain is the requested size */
253 p->tot_len = length;
254 /* set the length of the first pbuf in the chain */
255 p->len = LWIP_MIN(length, PBUF_POOL_BUFSIZE_ALIGNED - LWIP_MEM_ALIGN_SIZE(offset));
256 LWIP_ASSERT("check p->payload + p->len does not overflow pbuf",
257 ((u8_t*)p->payload + p->len <=
258 (u8_t*)p + SIZEOF_STRUCT_PBUF + PBUF_POOL_BUFSIZE_ALIGNED));
259 LWIP_ASSERT("PBUF_POOL_BUFSIZE must be bigger than MEM_ALIGNMENT",
260 (PBUF_POOL_BUFSIZE_ALIGNED - LWIP_MEM_ALIGN_SIZE(offset)) > 0 );
261 /* set reference count (needed here in case we fail) */
262 p->ref = 1;
263
264 /* now allocate the tail of the pbuf chain */
265
266 /* remember first pbuf for linkage in next iteration */
267 r = p;
268 /* remaining length to be allocated */
269 rem_len = length - p->len;
270 /* any remaining pbufs to be allocated? */
271 while (rem_len > 0) {
272 q = (struct pbuf *)memp_malloc(MEMP_PBUF_POOL);
273 if (q == NULL) {
274 PBUF_POOL_IS_EMPTY();
275 /* free chain so far allocated */
276 pbuf_free(p);
277 /* bail out unsuccesfully */
278 return NULL;
279 }
280 q->type = type;
281 q->flags = 0;
282 q->next = NULL;
283 /* make previous pbuf point to this pbuf */
284 r->next = q;
285 /* set total length of this pbuf and next in chain */
286 LWIP_ASSERT("rem_len < max_u16_t", rem_len < 0xffff);
287 q->tot_len = (u16_t)rem_len;
288 /* this pbuf length is pool size, unless smaller sized tail */
289 q->len = LWIP_MIN((u16_t)rem_len, PBUF_POOL_BUFSIZE_ALIGNED);
290 q->payload = (void *)((u8_t *)q + SIZEOF_STRUCT_PBUF);
291 LWIP_ASSERT("pbuf_alloc: pbuf q->payload properly aligned",
292 ((mem_ptr_t)q->payload % MEM_ALIGNMENT) == 0);
293 LWIP_ASSERT("check p->payload + p->len does not overflow pbuf",
294 ((u8_t*)p->payload + p->len <=
295 (u8_t*)p + SIZEOF_STRUCT_PBUF + PBUF_POOL_BUFSIZE_ALIGNED));
296 q->ref = 1;
297 /* calculate remaining length to be allocated */
298 rem_len -= q->len;
299 /* remember this pbuf for linkage in next iteration */
300 r = q;
301 }
302 /* end of chain */
303 /*r->next = NULL;*/
304
305 break;
306 case PBUF_RAM:
307 /* If pbuf is to be allocated in RAM, allocate memory for it. */
308 p = (struct pbuf*)mem_malloc(LWIP_MEM_ALIGN_SIZE(SIZEOF_STRUCT_PBUF + offset) + LWIP_MEM_ALIGN_SIZE(length));
309 if (p == NULL) {
310 return NULL;
311 }
312 /* Set up internal structure of the pbuf. */
313 p->payload = LWIP_MEM_ALIGN((void *)((u8_t *)p + SIZEOF_STRUCT_PBUF + offset));
314 p->len = p->tot_len = length;
315 p->next = NULL;
316 p->type = type;
317
318 LWIP_ASSERT("pbuf_alloc: pbuf->payload properly aligned",
319 ((mem_ptr_t)p->payload % MEM_ALIGNMENT) == 0);
320 break;
321 /* pbuf references existing (non-volatile static constant) ROM payload? */
322 case PBUF_ROM:
323 /* pbuf references existing (externally allocated) RAM payload? */
324 case PBUF_REF:
325 /* only allocate memory for the pbuf structure */
326 p = (struct pbuf *)memp_malloc(MEMP_PBUF);
327 if (p == NULL) {
328 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
329 ("pbuf_alloc: Could not allocate MEMP_PBUF for PBUF_%s.\n",
330 (type == PBUF_ROM) ? "ROM" : "REF"));
331 return NULL;
332 }
333 /* caller must set this field properly, afterwards */
334 p->payload = NULL;
335 p->len = p->tot_len = length;
336 p->next = NULL;
337 p->type = type;
338 break;
339 default:
340 LWIP_ASSERT("pbuf_alloc: erroneous type", 0);
341 return NULL;
342 }
343 /* set reference count */
344 p->ref = 1;
345 /* set flags */
346 p->flags = 0;
347 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloc(length=%"U16_F") == %p\n", length, (void *)p));
348 return p;
349}
350
351#if LWIP_SUPPORT_CUSTOM_PBUF
352/** Initialize a custom pbuf (already allocated).
353 *
354 * @param layer flag to define header size
355 * @param length size of the pbuf's payload
356 * @param type type of the pbuf (only used to treat the pbuf accordingly, as
357 * this function allocates no memory)
358 * @param p pointer to the custom pbuf to initialize (already allocated)
359 * @param payload_mem pointer to the buffer that is used for payload and headers,
360 * must be at least big enough to hold 'length' plus the header size,
361 * may be NULL if set later.
362 * ATTENTION: The caller is responsible for correct alignment of this buffer!!
363 * @param payload_mem_len the size of the 'payload_mem' buffer, must be at least
364 * big enough to hold 'length' plus the header size
365 */
366struct pbuf*
367pbuf_alloced_custom(pbuf_layer l, u16_t length, pbuf_type type, struct pbuf_custom *p,
368 void *payload_mem, u16_t payload_mem_len)
369{
370 u16_t offset;
371 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloced_custom(length=%"U16_F")\n", length));
372
373 /* determine header offset */
374 switch (l) {
375 case PBUF_TRANSPORT:
376 /* add room for transport (often TCP) layer header */
377 offset = PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN;
378 break;
379 case PBUF_IP:
380 /* add room for IP layer header */
381 offset = PBUF_LINK_HLEN + PBUF_IP_HLEN;
382 break;
383 case PBUF_LINK:
384 /* add room for link layer header */
385 offset = PBUF_LINK_HLEN;
386 break;
387 case PBUF_RAW:
388 offset = 0;
389 break;
390 default:
391 LWIP_ASSERT("pbuf_alloced_custom: bad pbuf layer", 0);
392 return NULL;
393 }
394
395 if (LWIP_MEM_ALIGN_SIZE(offset) + length > payload_mem_len) {
396 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_LEVEL_WARNING, ("pbuf_alloced_custom(length=%"U16_F") buffer too short\n", length));
397 return NULL;
398 }
399
400 p->pbuf.next = NULL;
401 if (payload_mem != NULL) {
402 p->pbuf.payload = (u8_t *)payload_mem + LWIP_MEM_ALIGN_SIZE(offset);
403 } else {
404 p->pbuf.payload = NULL;
405 }
406 p->pbuf.flags = PBUF_FLAG_IS_CUSTOM;
407 p->pbuf.len = p->pbuf.tot_len = length;
408 p->pbuf.type = type;
409 p->pbuf.ref = 1;
410 return &p->pbuf;
411}
412#endif /* LWIP_SUPPORT_CUSTOM_PBUF */
413
414/**
415 * Shrink a pbuf chain to a desired length.
416 *
417 * @param p pbuf to shrink.
418 * @param new_len desired new length of pbuf chain
419 *
420 * Depending on the desired length, the first few pbufs in a chain might
421 * be skipped and left unchanged. The new last pbuf in the chain will be
422 * resized, and any remaining pbufs will be freed.
423 *
424 * @note If the pbuf is ROM/REF, only the ->tot_len and ->len fields are adjusted.
425 * @note May not be called on a packet queue.
426 *
427 * @note Despite its name, pbuf_realloc cannot grow the size of a pbuf (chain).
428 */
429void
430pbuf_realloc(struct pbuf *p, u16_t new_len)
431{
432 struct pbuf *q;
433 u16_t rem_len; /* remaining length */
434 s32_t grow;
435
436 LWIP_ASSERT("pbuf_realloc: p != NULL", p != NULL);
437 LWIP_ASSERT("pbuf_realloc: sane p->type", p->type == PBUF_POOL ||
438 p->type == PBUF_ROM ||
439 p->type == PBUF_RAM ||
440 p->type == PBUF_REF);
441
442 /* desired length larger than current length? */
443 if (new_len >= p->tot_len) {
444 /* enlarging not yet supported */
445 return;
446 }
447
448 /* the pbuf chain grows by (new_len - p->tot_len) bytes
449 * (which may be negative in case of shrinking) */
450 grow = new_len - p->tot_len;
451
452 /* first, step over any pbufs that should remain in the chain */
453 rem_len = new_len;
454 q = p;
455 /* should this pbuf be kept? */
456 while (rem_len > q->len) {
457 /* decrease remaining length by pbuf length */
458 rem_len -= q->len;
459 /* decrease total length indicator */
460 LWIP_ASSERT("grow < max_u16_t", grow < 0xffff);
461 q->tot_len += (u16_t)grow;
462 /* proceed to next pbuf in chain */
463 q = q->next;
464 LWIP_ASSERT("pbuf_realloc: q != NULL", q != NULL);
465 }
466 /* we have now reached the new last pbuf (in q) */
467 /* rem_len == desired length for pbuf q */
468
469 /* shrink allocated memory for PBUF_RAM */
470 /* (other types merely adjust their length fields */
471 if ((q->type == PBUF_RAM) && (rem_len != q->len)) {
472 /* reallocate and adjust the length of the pbuf that will be split */
473 q = (struct pbuf *)mem_trim(q, (u16_t)((u8_t *)q->payload - (u8_t *)q) + rem_len);
474 LWIP_ASSERT("mem_trim returned q == NULL", q != NULL);
475 }
476 /* adjust length fields for new last pbuf */
477 q->len = rem_len;
478 q->tot_len = q->len;
479
480 /* any remaining pbufs in chain? */
481 if (q->next != NULL) {
482 /* free remaining pbufs in chain */
483 pbuf_free(q->next);
484 }
485 /* q is last packet in chain */
486 q->next = NULL;
487
488}
489
490/**
491 * Adjusts the payload pointer to hide or reveal headers in the payload.
492 *
493 * Adjusts the ->payload pointer so that space for a header
494 * (dis)appears in the pbuf payload.
495 *
496 * The ->payload, ->tot_len and ->len fields are adjusted.
497 *
498 * @param p pbuf to change the header size.
499 * @param header_size_increment Number of bytes to increment header size which
500 * increases the size of the pbuf. New space is on the front.
501 * (Using a negative value decreases the header size.)
502 * If hdr_size_inc is 0, this function does nothing and returns succesful.
503 *
504 * PBUF_ROM and PBUF_REF type buffers cannot have their sizes increased, so
505 * the call will fail. A check is made that the increase in header size does
506 * not move the payload pointer in front of the start of the buffer.
507 * @return non-zero on failure, zero on success.
508 *
509 */
510u8_t
511pbuf_header(struct pbuf *p, s16_t header_size_increment)
512{
513 u16_t type;
514 void *payload;
515 u16_t increment_magnitude;
516
517 LWIP_ASSERT("p != NULL", p != NULL);
518 if ((header_size_increment == 0) || (p == NULL)) {
519 return 0;
520 }
521
522 if (header_size_increment < 0){
523 increment_magnitude = -header_size_increment;
524 /* Check that we aren't going to move off the end of the pbuf */
525 LWIP_ERROR("increment_magnitude <= p->len", (increment_magnitude <= p->len), return 1;);
526 } else {
527 increment_magnitude = header_size_increment;
528#if 0
529 /* Can't assert these as some callers speculatively call
530 pbuf_header() to see if it's OK. Will return 1 below instead. */
531 /* Check that we've got the correct type of pbuf to work with */
532 LWIP_ASSERT("p->type == PBUF_RAM || p->type == PBUF_POOL",
533 p->type == PBUF_RAM || p->type == PBUF_POOL);
534 /* Check that we aren't going to move off the beginning of the pbuf */
535 LWIP_ASSERT("p->payload - increment_magnitude >= p + SIZEOF_STRUCT_PBUF",
536 (u8_t *)p->payload - increment_magnitude >= (u8_t *)p + SIZEOF_STRUCT_PBUF);
537#endif
538 }
539
540 type = p->type;
541 /* remember current payload pointer */
542 payload = p->payload;
543
544 /* pbuf types containing payloads? */
545 if (type == PBUF_RAM || type == PBUF_POOL) {
546 /* set new payload pointer */
547 p->payload = (u8_t *)p->payload - header_size_increment;
548 /* boundary check fails? */
549 if ((u8_t *)p->payload < (u8_t *)p + SIZEOF_STRUCT_PBUF) {
550 LWIP_DEBUGF( PBUF_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
551 ("pbuf_header: failed as %p < %p (not enough space for new header size)\n",
552 (void *)p->payload, (void *)(p + 1)));
553 /* restore old payload pointer */
554 p->payload = payload;
555 /* bail out unsuccesfully */
556 return 1;
557 }
558 /* pbuf types refering to external payloads? */
559 } else if (type == PBUF_REF || type == PBUF_ROM) {
560 /* hide a header in the payload? */
561 if ((header_size_increment < 0) && (increment_magnitude <= p->len)) {
562 /* increase payload pointer */
563 p->payload = (u8_t *)p->payload - header_size_increment;
564 } else {
565 /* cannot expand payload to front (yet!)
566 * bail out unsuccesfully */
567 return 1;
568 }
569 } else {
570 /* Unknown type */
571 LWIP_ASSERT("bad pbuf type", 0);
572 return 1;
573 }
574 /* modify pbuf length fields */
575 p->len += header_size_increment;
576 p->tot_len += header_size_increment;
577
578 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_header: old %p new %p (%"S16_F")\n",
579 (void *)payload, (void *)p->payload, header_size_increment));
580
581 return 0;
582}
583
584/**
585 * Dereference a pbuf chain or queue and deallocate any no-longer-used
586 * pbufs at the head of this chain or queue.
587 *
588 * Decrements the pbuf reference count. If it reaches zero, the pbuf is
589 * deallocated.
590 *
591 * For a pbuf chain, this is repeated for each pbuf in the chain,
592 * up to the first pbuf which has a non-zero reference count after
593 * decrementing. So, when all reference counts are one, the whole
594 * chain is free'd.
595 *
596 * @param p The pbuf (chain) to be dereferenced.
597 *
598 * @return the number of pbufs that were de-allocated
599 * from the head of the chain.
600 *
601 * @note MUST NOT be called on a packet queue (Not verified to work yet).
602 * @note the reference counter of a pbuf equals the number of pointers
603 * that refer to the pbuf (or into the pbuf).
604 *
605 * @internal examples:
606 *
607 * Assuming existing chains a->b->c with the following reference
608 * counts, calling pbuf_free(a) results in:
609 *
610 * 1->2->3 becomes ...1->3
611 * 3->3->3 becomes 2->3->3
612 * 1->1->2 becomes ......1
613 * 2->1->1 becomes 1->1->1
614 * 1->1->1 becomes .......
615 *
616 */
617u8_t
618pbuf_free(struct pbuf *p)
619{
620 u16_t type;
621 struct pbuf *q;
622 u8_t count;
623
624 if (p == NULL) {
625 LWIP_ASSERT("p != NULL", p != NULL);
626 /* if assertions are disabled, proceed with debug output */
627 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
628 ("pbuf_free(p == NULL) was called.\n"));
629 return 0;
630 }
631 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_free(%p)\n", (void *)p));
632
633 PERF_START;
634
635 LWIP_ASSERT("pbuf_free: sane type",
636 p->type == PBUF_RAM || p->type == PBUF_ROM ||
637 p->type == PBUF_REF || p->type == PBUF_POOL);
638
639 count = 0;
640 /* de-allocate all consecutive pbufs from the head of the chain that
641 * obtain a zero reference count after decrementing*/
642 while (p != NULL) {
643 u16_t ref;
644 SYS_ARCH_DECL_PROTECT(old_level);
645 /* Since decrementing ref cannot be guaranteed to be a single machine operation
646 * we must protect it. We put the new ref into a local variable to prevent
647 * further protection. */
648 SYS_ARCH_PROTECT(old_level);
649 /* all pbufs in a chain are referenced at least once */
650 LWIP_ASSERT("pbuf_free: p->ref > 0", p->ref > 0);
651 /* decrease reference count (number of pointers to pbuf) */
652 ref = --(p->ref);
653 SYS_ARCH_UNPROTECT(old_level);
654 /* this pbuf is no longer referenced to? */
655 if (ref == 0) {
656 /* remember next pbuf in chain for next iteration */
657 q = p->next;
658 LWIP_DEBUGF( PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_free: deallocating %p\n", (void *)p));
659 type = p->type;
660#if LWIP_SUPPORT_CUSTOM_PBUF
661 /* is this a custom pbuf? */
662 if ((p->flags & PBUF_FLAG_IS_CUSTOM) != 0) {
663 struct pbuf_custom *pc = (struct pbuf_custom*)p;
664 LWIP_ASSERT("pc->custom_free_function != NULL", pc->custom_free_function != NULL);
665 pc->custom_free_function(p);
666 } else
667#endif /* LWIP_SUPPORT_CUSTOM_PBUF */
668 {
669 /* is this a pbuf from the pool? */
670 if (type == PBUF_POOL) {
671 memp_free(MEMP_PBUF_POOL, p);
672 /* is this a ROM or RAM referencing pbuf? */
673 } else if (type == PBUF_ROM || type == PBUF_REF) {
674 memp_free(MEMP_PBUF, p);
675 /* type == PBUF_RAM */
676 } else {
677 mem_free(p);
678 }
679 }
680 count++;
681 /* proceed to next pbuf */
682 p = q;
683 /* p->ref > 0, this pbuf is still referenced to */
684 /* (and so the remaining pbufs in chain as well) */
685 } else {
686 LWIP_DEBUGF( PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_free: %p has ref %"U16_F", ending here.\n", (void *)p, ref));
687 /* stop walking through the chain */
688 p = NULL;
689 }
690 }
691 PERF_STOP("pbuf_free");
692 /* return number of de-allocated pbufs */
693 return count;
694}
695
696/**
697 * Count number of pbufs in a chain
698 *
699 * @param p first pbuf of chain
700 * @return the number of pbufs in a chain
701 */
702
703u8_t
704pbuf_clen(struct pbuf *p)
705{
706 u8_t len;
707
708 len = 0;
709 while (p != NULL) {
710 ++len;
711 p = p->next;
712 }
713 return len;
714}
715
716/**
717 * Increment the reference count of the pbuf.
718 *
719 * @param p pbuf to increase reference counter of
720 *
721 */
722void
723pbuf_ref(struct pbuf *p)
724{
725 SYS_ARCH_DECL_PROTECT(old_level);
726 /* pbuf given? */
727 if (p != NULL) {
728 SYS_ARCH_PROTECT(old_level);
729 ++(p->ref);
730 SYS_ARCH_UNPROTECT(old_level);
731 }
732}
733
734/**
735 * Concatenate two pbufs (each may be a pbuf chain) and take over
736 * the caller's reference of the tail pbuf.
737 *
738 * @note The caller MAY NOT reference the tail pbuf afterwards.
739 * Use pbuf_chain() for that purpose.
740 *
741 * @see pbuf_chain()
742 */
743
744void
745pbuf_cat(struct pbuf *h, struct pbuf *t)
746{
747 struct pbuf *p;
748
749 LWIP_ERROR("(h != NULL) && (t != NULL) (programmer violates API)",
750 ((h != NULL) && (t != NULL)), return;);
751
752 /* proceed to last pbuf of chain */
753 for (p = h; p->next != NULL; p = p->next) {
754 /* add total length of second chain to all totals of first chain */
755 p->tot_len += t->tot_len;
756 }
757 /* { p is last pbuf of first h chain, p->next == NULL } */
758 LWIP_ASSERT("p->tot_len == p->len (of last pbuf in chain)", p->tot_len == p->len);
759 LWIP_ASSERT("p->next == NULL", p->next == NULL);
760 /* add total length of second chain to last pbuf total of first chain */
761 p->tot_len += t->tot_len;
762 /* chain last pbuf of head (p) with first of tail (t) */
763 p->next = t;
764 /* p->next now references t, but the caller will drop its reference to t,
765 * so netto there is no change to the reference count of t.
766 */
767}
768
769/**
770 * Chain two pbufs (or pbuf chains) together.
771 *
772 * The caller MUST call pbuf_free(t) once it has stopped
773 * using it. Use pbuf_cat() instead if you no longer use t.
774 *
775 * @param h head pbuf (chain)
776 * @param t tail pbuf (chain)
777 * @note The pbufs MUST belong to the same packet.
778 * @note MAY NOT be called on a packet queue.
779 *
780 * The ->tot_len fields of all pbufs of the head chain are adjusted.
781 * The ->next field of the last pbuf of the head chain is adjusted.
782 * The ->ref field of the first pbuf of the tail chain is adjusted.
783 *
784 */
785void
786pbuf_chain(struct pbuf *h, struct pbuf *t)
787{
788 pbuf_cat(h, t);
789 /* t is now referenced by h */
790 pbuf_ref(t);
791 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_chain: %p references %p\n", (void *)h, (void *)t));
792}
793
794/**
795 * Dechains the first pbuf from its succeeding pbufs in the chain.
796 *
797 * Makes p->tot_len field equal to p->len.
798 * @param p pbuf to dechain
799 * @return remainder of the pbuf chain, or NULL if it was de-allocated.
800 * @note May not be called on a packet queue.
801 */
802struct pbuf *
803pbuf_dechain(struct pbuf *p)
804{
805 struct pbuf *q;
806 u8_t tail_gone = 1;
807 /* tail */
808 q = p->next;
809 /* pbuf has successor in chain? */
810 if (q != NULL) {
811 /* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */
812 LWIP_ASSERT("p->tot_len == p->len + q->tot_len", q->tot_len == p->tot_len - p->len);
813 /* enforce invariant if assertion is disabled */
814 q->tot_len = p->tot_len - p->len;
815 /* decouple pbuf from remainder */
816 p->next = NULL;
817 /* total length of pbuf p is its own length only */
818 p->tot_len = p->len;
819 /* q is no longer referenced by p, free it */
820 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_dechain: unreferencing %p\n", (void *)q));
821 tail_gone = pbuf_free(q);
822 if (tail_gone > 0) {
823 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE,
824 ("pbuf_dechain: deallocated %p (as it is no longer referenced)\n", (void *)q));
825 }
826 /* return remaining tail or NULL if deallocated */
827 }
828 /* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */
829 LWIP_ASSERT("p->tot_len == p->len", p->tot_len == p->len);
830 return ((tail_gone > 0) ? NULL : q);
831}
832
833/**
834 *
835 * Create PBUF_RAM copies of pbufs.
836 *
837 * Used to queue packets on behalf of the lwIP stack, such as
838 * ARP based queueing.
839 *
840 * @note You MUST explicitly use p = pbuf_take(p);
841 *
842 * @note Only one packet is copied, no packet queue!
843 *
844 * @param p_to pbuf destination of the copy
845 * @param p_from pbuf source of the copy
846 *
847 * @return ERR_OK if pbuf was copied
848 * ERR_ARG if one of the pbufs is NULL or p_to is not big
849 * enough to hold p_from
850 */
851err_t
852pbuf_copy(struct pbuf *p_to, struct pbuf *p_from)
853{
854 u16_t offset_to=0, offset_from=0, len;
855
856 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_copy(%p, %p)\n",
857 (void*)p_to, (void*)p_from));
858
859 /* is the target big enough to hold the source? */
860 LWIP_ERROR("pbuf_copy: target not big enough to hold source", ((p_to != NULL) &&
861 (p_from != NULL) && (p_to->tot_len >= p_from->tot_len)), return ERR_ARG;);
862
863 /* iterate through pbuf chain */
864 do
865 {
866 /* copy one part of the original chain */
867 if ((p_to->len - offset_to) >= (p_from->len - offset_from)) {
868 /* complete current p_from fits into current p_to */
869 len = p_from->len - offset_from;
870 } else {
871 /* current p_from does not fit into current p_to */
872 len = p_to->len - offset_to;
873 }
874 MEMCPY((u8_t*)p_to->payload + offset_to, (u8_t*)p_from->payload + offset_from, len);
875 offset_to += len;
876 offset_from += len;
877 LWIP_ASSERT("offset_to <= p_to->len", offset_to <= p_to->len);
878 LWIP_ASSERT("offset_from <= p_from->len", offset_from <= p_from->len);
879 if (offset_from >= p_from->len) {
880 /* on to next p_from (if any) */
881 offset_from = 0;
882 p_from = p_from->next;
883 }
884 if (offset_to == p_to->len) {
885 /* on to next p_to (if any) */
886 offset_to = 0;
887 p_to = p_to->next;
888 LWIP_ERROR("p_to != NULL", (p_to != NULL) || (p_from == NULL) , return ERR_ARG;);
889 }
890
891 if((p_from != NULL) && (p_from->len == p_from->tot_len)) {
892 /* don't copy more than one packet! */
893 LWIP_ERROR("pbuf_copy() does not allow packet queues!\n",
894 (p_from->next == NULL), return ERR_VAL;);
895 }
896 if((p_to != NULL) && (p_to->len == p_to->tot_len)) {
897 /* don't copy more than one packet! */
898 LWIP_ERROR("pbuf_copy() does not allow packet queues!\n",
899 (p_to->next == NULL), return ERR_VAL;);
900 }
901 } while (p_from);
902 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_copy: end of chain reached.\n"));
903 return ERR_OK;
904}
905
906/**
907 * Copy (part of) the contents of a packet buffer
908 * to an application supplied buffer.
909 *
910 * @param buf the pbuf from which to copy data
911 * @param dataptr the application supplied buffer
912 * @param len length of data to copy (dataptr must be big enough). No more
913 * than buf->tot_len will be copied, irrespective of len
914 * @param offset offset into the packet buffer from where to begin copying len bytes
915 * @return the number of bytes copied, or 0 on failure
916 */
917u16_t
918pbuf_copy_partial(struct pbuf *buf, void *dataptr, u16_t len, u16_t offset)
919{
920 struct pbuf *p;
921 u16_t left;
922 u16_t buf_copy_len;
923 u16_t copied_total = 0;
924
925 LWIP_ERROR("pbuf_copy_partial: invalid buf", (buf != NULL), return 0;);
926 LWIP_ERROR("pbuf_copy_partial: invalid dataptr", (dataptr != NULL), return 0;);
927
928 left = 0;
929
930 if((buf == NULL) || (dataptr == NULL)) {
931 return 0;
932 }
933
934 /* Note some systems use byte copy if dataptr or one of the pbuf payload pointers are unaligned. */
935 for(p = buf; len != 0 && p != NULL; p = p->next) {
936 if ((offset != 0) && (offset >= p->len)) {
937 /* don't copy from this buffer -> on to the next */
938 offset -= p->len;
939 } else {
940 /* copy from this buffer. maybe only partially. */
941 buf_copy_len = p->len - offset;
942 if (buf_copy_len > len)
943 buf_copy_len = len;
944 /* copy the necessary parts of the buffer */
945 MEMCPY(&((char*)dataptr)[left], &((char*)p->payload)[offset], buf_copy_len);
946 copied_total += buf_copy_len;
947 left += buf_copy_len;
948 len -= buf_copy_len;
949 offset = 0;
950 }
951 }
952 return copied_total;
953}
954
955/**
956 * Copy application supplied data into a pbuf.
957 * This function can only be used to copy the equivalent of buf->tot_len data.
958 *
959 * @param buf pbuf to fill with data
960 * @param dataptr application supplied data buffer
961 * @param len length of the application supplied data buffer
962 *
963 * @return ERR_OK if successful, ERR_MEM if the pbuf is not big enough
964 */
965err_t
966pbuf_take(struct pbuf *buf, const void *dataptr, u16_t len)
967{
968 struct pbuf *p;
969 u16_t buf_copy_len;
970 u16_t total_copy_len = len;
971 u16_t copied_total = 0;
972
973 LWIP_ERROR("pbuf_take: invalid buf", (buf != NULL), return 0;);
974 LWIP_ERROR("pbuf_take: invalid dataptr", (dataptr != NULL), return 0;);
975
976 if ((buf == NULL) || (dataptr == NULL) || (buf->tot_len < len)) {
977 return ERR_ARG;
978 }
979
980 /* Note some systems use byte copy if dataptr or one of the pbuf payload pointers are unaligned. */
981 for(p = buf; total_copy_len != 0; p = p->next) {
982 LWIP_ASSERT("pbuf_take: invalid pbuf", p != NULL);
983 buf_copy_len = total_copy_len;
984 if (buf_copy_len > p->len) {
985 /* this pbuf cannot hold all remaining data */
986 buf_copy_len = p->len;
987 }
988 /* copy the necessary parts of the buffer */
989 MEMCPY(p->payload, &((char*)dataptr)[copied_total], buf_copy_len);
990 total_copy_len -= buf_copy_len;
991 copied_total += buf_copy_len;
992 }
993 LWIP_ASSERT("did not copy all data", total_copy_len == 0 && copied_total == len);
994 return ERR_OK;
995}
996
997/**
998 * Creates a single pbuf out of a queue of pbufs.
999 *
1000 * @remark: Either the source pbuf 'p' is freed by this function or the original
1001 * pbuf 'p' is returned, therefore the caller has to check the result!
1002 *
1003 * @param p the source pbuf
1004 * @param layer pbuf_layer of the new pbuf
1005 *
1006 * @return a new, single pbuf (p->next is NULL)
1007 * or the old pbuf if allocation fails
1008 */
1009struct pbuf*
1010pbuf_coalesce(struct pbuf *p, pbuf_layer layer)
1011{
1012 struct pbuf *q;
1013 err_t err;
1014 if (p->next == NULL) {
1015 return p;
1016 }
1017 q = pbuf_alloc(layer, p->tot_len, PBUF_RAM);
1018 if (q == NULL) {
1019 /* @todo: what do we do now? */
1020 return p;
1021 }
1022 err = pbuf_copy(q, p);
1023 LWIP_ASSERT("pbuf_copy failed", err == ERR_OK);
1024 pbuf_free(p);
1025 return q;
1026}
1027
1028#if LWIP_CHECKSUM_ON_COPY
1029/**
1030 * Copies data into a single pbuf (*not* into a pbuf queue!) and updates
1031 * the checksum while copying
1032 *
1033 * @param p the pbuf to copy data into
1034 * @param start_offset offset of p->payload where to copy the data to
1035 * @param dataptr data to copy into the pbuf
1036 * @param len length of data to copy into the pbuf
1037 * @param chksum pointer to the checksum which is updated
1038 * @return ERR_OK if successful, another error if the data does not fit
1039 * within the (first) pbuf (no pbuf queues!)
1040 */
1041err_t
1042pbuf_fill_chksum(struct pbuf *p, u16_t start_offset, const void *dataptr,
1043 u16_t len, u16_t *chksum)
1044{
1045 u32_t acc;
1046 u16_t copy_chksum;
1047 char *dst_ptr;
1048 LWIP_ASSERT("p != NULL", p != NULL);
1049 LWIP_ASSERT("dataptr != NULL", dataptr != NULL);
1050 LWIP_ASSERT("chksum != NULL", chksum != NULL);
1051 LWIP_ASSERT("len != 0", len != 0);
1052
1053 if ((start_offset >= p->len) || (start_offset + len > p->len)) {
1054 return ERR_ARG;
1055 }
1056
1057 dst_ptr = ((char*)p->payload) + start_offset;
1058 copy_chksum = LWIP_CHKSUM_COPY(dst_ptr, dataptr, len);
1059 if ((start_offset & 1) != 0) {
1060 copy_chksum = SWAP_BYTES_IN_WORD(copy_chksum);
1061 }
1062 acc = *chksum;
1063 acc += copy_chksum;
1064 *chksum = FOLD_U32T(acc);
1065 return ERR_OK;
1066}
1067#endif /* LWIP_CHECKSUM_ON_COPY */
1068
1069 /** Get one byte from the specified position in a pbuf
1070 * WARNING: returns zero for offset >= p->tot_len
1071 *
1072 * @param p pbuf to parse
1073 * @param offset offset into p of the byte to return
1074 * @return byte at an offset into p OR ZERO IF 'offset' >= p->tot_len
1075 */
1076u8_t
1077pbuf_get_at(struct pbuf* p, u16_t offset)
1078{
1079 u16_t copy_from = offset;
1080 struct pbuf* q = p;
1081
1082 /* get the correct pbuf */
1083 while ((q != NULL) && (q->len <= copy_from)) {
1084 copy_from -= q->len;
1085 q = q->next;
1086 }
1087 /* return requested data if pbuf is OK */
1088 if ((q != NULL) && (q->len > copy_from)) {
1089 return ((u8_t*)q->payload)[copy_from];
1090 }
1091 return 0;
1092}
1093
1094/** Compare pbuf contents at specified offset with memory s2, both of length n
1095 *
1096 * @param p pbuf to compare
1097 * @param offset offset into p at wich to start comparing
1098 * @param s2 buffer to compare
1099 * @param n length of buffer to compare
1100 * @return zero if equal, nonzero otherwise
1101 * (0xffff if p is too short, diffoffset+1 otherwise)
1102 */
1103u16_t
1104pbuf_memcmp(struct pbuf* p, u16_t offset, const void* s2, u16_t n)
1105{
1106 u16_t start = offset;
1107 struct pbuf* q = p;
1108
1109 /* get the correct pbuf */
1110 while ((q != NULL) && (q->len <= start)) {
1111 start -= q->len;
1112 q = q->next;
1113 }
1114 /* return requested data if pbuf is OK */
1115 if ((q != NULL) && (q->len > start)) {
1116 u16_t i;
1117 for(i = 0; i < n; i++) {
1118 u8_t a = pbuf_get_at(q, start + i);
1119 u8_t b = ((u8_t*)s2)[i];
1120 if (a != b) {
1121 return i+1;
1122 }
1123 }
1124 return 0;
1125 }
1126 return 0xffff;
1127}
1128
1129/** Find occurrence of mem (with length mem_len) in pbuf p, starting at offset
1130 * start_offset.
1131 *
1132 * @param p pbuf to search, maximum length is 0xFFFE since 0xFFFF is used as
1133 * return value 'not found'
1134 * @param mem search for the contents of this buffer
1135 * @param mem_len length of 'mem'
1136 * @param start_offset offset into p at which to start searching
1137 * @return 0xFFFF if substr was not found in p or the index where it was found
1138 */
1139u16_t
1140pbuf_memfind(struct pbuf* p, const void* mem, u16_t mem_len, u16_t start_offset)
1141{
1142 u16_t i;
1143 u16_t max = p->tot_len - mem_len;
1144 if (p->tot_len >= mem_len + start_offset) {
1145 for(i = start_offset; i <= max; ) {
1146 u16_t plus = pbuf_memcmp(p, i, mem, mem_len);
1147 if (plus == 0) {
1148 return i;
1149 } else {
1150 i += plus;
1151 }
1152 }
1153 }
1154 return 0xFFFF;
1155}
1156
1157/** Find occurrence of substr with length substr_len in pbuf p, start at offset
1158 * start_offset
1159 * WARNING: in contrast to strstr(), this one does not stop at the first \0 in
1160 * the pbuf/source string!
1161 *
1162 * @param p pbuf to search, maximum length is 0xFFFE since 0xFFFF is used as
1163 * return value 'not found'
1164 * @param substr string to search for in p, maximum length is 0xFFFE
1165 * @return 0xFFFF if substr was not found in p or the index where it was found
1166 */
1167u16_t
1168pbuf_strstr(struct pbuf* p, const char* substr)
1169{
1170 size_t substr_len;
1171 if ((substr == NULL) || (substr[0] == 0) || (p->tot_len == 0xFFFF)) {
1172 return 0xFFFF;
1173 }
1174 substr_len = strlen(substr);
1175 if (substr_len >= 0xFFFF) {
1176 return 0xFFFF;
1177 }
1178 return pbuf_memfind(p, substr, (u16_t)substr_len, 0);
1179}
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