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