1 /**
2 * @file
3 * Packet buffer management
4 */
5
6 /**
7 * @defgroup pbuf Packet buffers (PBUF)
8 * @ingroup infrastructure
9 *
10 * Packets are built from the pbuf data structure. It supports dynamic
11 * memory allocation for packet contents or can reference externally
12 * managed packet contents both in RAM and ROM. Quick allocation for
13 * incoming packets is provided through pools with fixed sized pbufs.
14 *
15 * A packet may span over multiple pbufs, chained as a singly linked
16 * list. This is called a "pbuf chain".
17 *
18 * Multiple packets may be queued, also using this singly linked list.
19 * This is called a "packet queue".
20 *
21 * So, a packet queue consists of one or more pbuf chains, each of
22 * which consist of one or more pbufs. CURRENTLY, PACKET QUEUES ARE
23 * NOT SUPPORTED!!! Use helper structs to queue multiple packets.
24 *
25 * The differences between a pbuf chain and a packet queue are very
26 * precise but subtle.
27 *
28 * The last pbuf of a packet has a ->tot_len field that equals the
29 * ->len field. It can be found by traversing the list. If the last
30 * pbuf of a packet has a ->next field other than NULL, more packets
31 * are on the queue.
32 *
33 * Therefore, looping through a pbuf of a single packet, has an
34 * loop end condition (tot_len == p->len), NOT (next == NULL).
35 *
36 * Example of custom pbuf usage for zero-copy RX:
37 @code{.c}
38 typedef struct my_custom_pbuf
39 {
40 struct pbuf_custom p;
41 void* dma_descriptor;
42 } my_custom_pbuf_t;
43
44 LWIP_MEMPOOL_DECLARE(RX_POOL, 10, sizeof(my_custom_pbuf_t), "Zero-copy RX PBUF pool");
45
46 void my_pbuf_free_custom(void* p)
47 {
48 my_custom_pbuf_t* my_puf = (my_custom_pbuf_t*)p;
49
50 LOCK_INTERRUPTS();
51 free_rx_dma_descriptor(my_pbuf->dma_descriptor);
52 LWIP_MEMPOOL_FREE(RX_POOL, my_pbuf);
53 UNLOCK_INTERRUPTS();
54 }
55
56 void eth_rx_irq()
57 {
58 dma_descriptor* dma_desc = get_RX_DMA_descriptor_from_ethernet();
59 my_custom_pbuf_t* my_pbuf = (my_custom_pbuf_t*)LWIP_MEMPOOL_ALLOC(RX_POOL);
60
61 my_pbuf->p.custom_free_function = my_pbuf_free_custom;
62 my_pbuf->dma_descriptor = dma_desc;
63
64 invalidate_cpu_cache(dma_desc->rx_data, dma_desc->rx_length);
65
66 struct pbuf* p = pbuf_alloced_custom(PBUF_RAW,
67 dma_desc->rx_length,
68 PBUF_REF,
69 &my_pbuf->p,
70 dma_desc->rx_data,
71 dma_desc->max_buffer_size);
72
73 if(netif->input(p, netif) != ERR_OK) {
74 pbuf_free(p);
75 }
76 }
77 @endcode
78 */
79
80 /*
81 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
82 * All rights reserved.
83 *
84 * Redistribution and use in source and binary forms, with or without modification,
85 * are permitted provided that the following conditions are met:
86 *
87 * 1. Redistributions of source code must retain the above copyright notice,
88 * this list of conditions and the following disclaimer.
89 * 2. Redistributions in binary form must reproduce the above copyright notice,
90 * this list of conditions and the following disclaimer in the documentation
91 * and/or other materials provided with the distribution.
92 * 3. The name of the author may not be used to endorse or promote products
93 * derived from this software without specific prior written permission.
94 *
95 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
96 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
97 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
98 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
99 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
100 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
101 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
102 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
103 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
104 * OF SUCH DAMAGE.
105 *
106 * This file is part of the lwIP TCP/IP stack.
107 *
108 * Author: Adam Dunkels <adam@sics.se>
109 *
110 */
111
112 #include "lwip/opt.h"
113
114 #include "lwip/stats.h"
115 #include "lwip/def.h"
116 #include "lwip/mem.h"
117 #include "lwip/memp.h"
118 #include "lwip/pbuf.h"
119 #include "lwip/sys.h"
120 #include "lwip/netif.h"
121 #if LWIP_TCP && TCP_QUEUE_OOSEQ
122 #include "lwip/priv/tcp_priv.h"
123 #endif
124 #if LWIP_CHECKSUM_ON_COPY
125 #include "lwip/inet_chksum.h"
126 #endif
127
128 #include <string.h>
129
130 #define SIZEOF_STRUCT_PBUF LWIP_MEM_ALIGN_SIZE(sizeof(struct pbuf))
131 /* Since the pool is created in memp, PBUF_POOL_BUFSIZE will be automatically
132 aligned there. Therefore, PBUF_POOL_BUFSIZE_ALIGNED can be used here. */
133 #define PBUF_POOL_BUFSIZE_ALIGNED LWIP_MEM_ALIGN_SIZE(PBUF_POOL_BUFSIZE)
134
135 #if !LWIP_TCP || !TCP_QUEUE_OOSEQ || !PBUF_POOL_FREE_OOSEQ
136 #define PBUF_POOL_IS_EMPTY()
137 #else /* !LWIP_TCP || !TCP_QUEUE_OOSEQ || !PBUF_POOL_FREE_OOSEQ */
138
139 #if !NO_SYS
140 #ifndef PBUF_POOL_FREE_OOSEQ_QUEUE_CALL
141 #include "lwip/tcpip.h"
142 #define PBUF_POOL_FREE_OOSEQ_QUEUE_CALL() do { \
143 if (tcpip_callback_with_block(pbuf_free_ooseq_callback, NULL, 0) != ERR_OK) { \
144 SYS_ARCH_PROTECT(old_level); \
145 pbuf_free_ooseq_pending = 0; \
146 SYS_ARCH_UNPROTECT(old_level); \
147 } } while(0)
148 #endif /* PBUF_POOL_FREE_OOSEQ_QUEUE_CALL */
149 #endif /* !NO_SYS */
150
151 volatile u8_t pbuf_free_ooseq_pending;
152 #define PBUF_POOL_IS_EMPTY() pbuf_pool_is_empty()
153
154 /**
155 * Attempt to reclaim some memory from queued out-of-sequence TCP segments
156 * if we run out of pool pbufs. It's better to give priority to new packets
157 * if we're running out.
158 *
159 * This must be done in the correct thread context therefore this function
160 * can only be used with NO_SYS=0 and through tcpip_callback.
161 */
162 #if !NO_SYS
163 static
164 #endif /* !NO_SYS */
165 void
pbuf_free_ooseq(void)166 pbuf_free_ooseq(void)
167 {
168 struct tcp_pcb* pcb;
169 SYS_ARCH_SET(pbuf_free_ooseq_pending, 0);
170
171 for (pcb = tcp_active_pcbs; NULL != pcb; pcb = pcb->next) {
172 if (NULL != pcb->ooseq) {
173 /** Free the ooseq pbufs of one PCB only */
174 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_free_ooseq: freeing out-of-sequence pbufs\n"));
175 tcp_segs_free(pcb->ooseq);
176 pcb->ooseq = NULL;
177 return;
178 }
179 }
180 }
181
182 #if !NO_SYS
183 /**
184 * Just a callback function for tcpip_callback() that calls pbuf_free_ooseq().
185 */
186 static void
pbuf_free_ooseq_callback(void * arg)187 pbuf_free_ooseq_callback(void *arg)
188 {
189 LWIP_UNUSED_ARG(arg);
190 pbuf_free_ooseq();
191 }
192 #endif /* !NO_SYS */
193
194 /** Queue a call to pbuf_free_ooseq if not already queued. */
195 static void
pbuf_pool_is_empty(void)196 pbuf_pool_is_empty(void)
197 {
198 #ifndef PBUF_POOL_FREE_OOSEQ_QUEUE_CALL
199 SYS_ARCH_SET(pbuf_free_ooseq_pending, 1);
200 #else /* PBUF_POOL_FREE_OOSEQ_QUEUE_CALL */
201 u8_t queued;
202 SYS_ARCH_DECL_PROTECT(old_level);
203 SYS_ARCH_PROTECT(old_level);
204 queued = pbuf_free_ooseq_pending;
205 pbuf_free_ooseq_pending = 1;
206 SYS_ARCH_UNPROTECT(old_level);
207
208 if (!queued) {
209 /* queue a call to pbuf_free_ooseq if not already queued */
210 PBUF_POOL_FREE_OOSEQ_QUEUE_CALL();
211 }
212 #endif /* PBUF_POOL_FREE_OOSEQ_QUEUE_CALL */
213 }
214 #endif /* !LWIP_TCP || !TCP_QUEUE_OOSEQ || !PBUF_POOL_FREE_OOSEQ */
215
216 /**
217 * @ingroup pbuf
218 * Allocates a pbuf of the given type (possibly a chain for PBUF_POOL type).
219 *
220 * The actual memory allocated for the pbuf is determined by the
221 * layer at which the pbuf is allocated and the requested size
222 * (from the size parameter).
223 *
224 * @param layer flag to define header size
225 * @param length size of the pbuf's payload
226 * @param type this parameter decides how and where the pbuf
227 * should be allocated as follows:
228 *
229 * - PBUF_RAM: buffer memory for pbuf is allocated as one large
230 * chunk. This includes protocol headers as well.
231 * - PBUF_ROM: no buffer memory is allocated for the pbuf, even for
232 * protocol headers. Additional headers must be prepended
233 * by allocating another pbuf and chain in to the front of
234 * the ROM pbuf. It is assumed that the memory used is really
235 * similar to ROM in that it is immutable and will not be
236 * changed. Memory which is dynamic should generally not
237 * be attached to PBUF_ROM pbufs. Use PBUF_REF instead.
238 * - PBUF_REF: no buffer memory is allocated for the pbuf, even for
239 * protocol headers. It is assumed that the pbuf is only
240 * being used in a single thread. If the pbuf gets queued,
241 * then pbuf_take should be called to copy the buffer.
242 * - PBUF_POOL: the pbuf is allocated as a pbuf chain, with pbufs from
243 * the pbuf pool that is allocated during pbuf_init().
244 *
245 * @return the allocated pbuf. If multiple pbufs where allocated, this
246 * is the first pbuf of a pbuf chain.
247 */
248 struct pbuf *
pbuf_alloc(pbuf_layer layer,u16_t length,pbuf_type type)249 pbuf_alloc(pbuf_layer layer, u16_t length, pbuf_type type)
250 {
251 struct pbuf *p, *q, *r;
252 u16_t offset;
253 s32_t rem_len; /* remaining length */
254 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloc(length=%"U16_F")\n", length));
255
256 /* determine header offset */
257 switch (layer) {
258 case PBUF_TRANSPORT:
259 /* add room for transport (often TCP) layer header */
260 offset = PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN;
261 break;
262 case PBUF_IP:
263 /* add room for IP layer header */
264 offset = PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN + PBUF_IP_HLEN;
265 break;
266 case PBUF_LINK:
267 /* add room for link layer header */
268 offset = PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN;
269 break;
270 case PBUF_RAW_TX:
271 /* add room for encapsulating link layer headers (e.g. 802.11) */
272 offset = PBUF_LINK_ENCAPSULATION_HLEN;
273 break;
274 case PBUF_RAW:
275 /* no offset (e.g. RX buffers or chain successors) */
276 offset = 0;
277 break;
278 default:
279 LWIP_ASSERT("pbuf_alloc: bad pbuf layer", 0);
280 return NULL;
281 }
282
283 switch (type) {
284 case PBUF_POOL:
285 /* allocate head of pbuf chain into p */
286 p = (struct pbuf *)memp_malloc(MEMP_PBUF_POOL);
287 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloc: allocated pbuf %p\n", (void *)p));
288 if (p == NULL) {
289 PBUF_POOL_IS_EMPTY();
290 return NULL;
291 }
292 p->type = type;
293 p->next = NULL;
294 p->if_idx = NETIF_NO_INDEX;
295
296 /* make the payload pointer point 'offset' bytes into pbuf data memory */
297 p->payload = LWIP_MEM_ALIGN((void *)((u8_t *)p + (SIZEOF_STRUCT_PBUF + offset)));
298 LWIP_ASSERT("pbuf_alloc: pbuf p->payload properly aligned",
299 ((mem_ptr_t)p->payload % MEM_ALIGNMENT) == 0);
300 /* the total length of the pbuf chain is the requested size */
301 p->tot_len = length;
302 /* set the length of the first pbuf in the chain */
303 p->len = LWIP_MIN(length, PBUF_POOL_BUFSIZE_ALIGNED - LWIP_MEM_ALIGN_SIZE(offset));
304 LWIP_ASSERT("check p->payload + p->len does not overflow pbuf",
305 ((u8_t*)p->payload + p->len <=
306 (u8_t*)p + SIZEOF_STRUCT_PBUF + PBUF_POOL_BUFSIZE_ALIGNED));
307 LWIP_ASSERT("PBUF_POOL_BUFSIZE must be bigger than MEM_ALIGNMENT",
308 (PBUF_POOL_BUFSIZE_ALIGNED - LWIP_MEM_ALIGN_SIZE(offset)) > 0 );
309 /* set reference count (needed here in case we fail) */
310 p->ref = 1;
311
312 /* now allocate the tail of the pbuf chain */
313
314 /* remember first pbuf for linkage in next iteration */
315 r = p;
316 /* remaining length to be allocated */
317 rem_len = length - p->len;
318 /* any remaining pbufs to be allocated? */
319 while (rem_len > 0) {
320 q = (struct pbuf *)memp_malloc(MEMP_PBUF_POOL);
321 if (q == NULL) {
322 PBUF_POOL_IS_EMPTY();
323 /* free chain so far allocated */
324 pbuf_free(p);
325 /* bail out unsuccessfully */
326 return NULL;
327 }
328 q->type = type;
329 q->flags = 0;
330 q->next = NULL;
331 /* make previous pbuf point to this pbuf */
332 r->next = q;
333 /* set total length of this pbuf and next in chain */
334 LWIP_ASSERT("rem_len < max_u16_t", rem_len < 0xffff);
335 q->tot_len = (u16_t)rem_len;
336 /* this pbuf length is pool size, unless smaller sized tail */
337 q->len = LWIP_MIN((u16_t)rem_len, PBUF_POOL_BUFSIZE_ALIGNED);
338 q->payload = (void *)((u8_t *)q + SIZEOF_STRUCT_PBUF);
339 LWIP_ASSERT("pbuf_alloc: pbuf q->payload properly aligned",
340 ((mem_ptr_t)q->payload % MEM_ALIGNMENT) == 0);
341 LWIP_ASSERT("check p->payload + p->len does not overflow pbuf",
342 ((u8_t*)p->payload + p->len <=
343 (u8_t*)p + SIZEOF_STRUCT_PBUF + PBUF_POOL_BUFSIZE_ALIGNED));
344 q->ref = 1;
345 /* calculate remaining length to be allocated */
346 rem_len -= q->len;
347 /* remember this pbuf for linkage in next iteration */
348 r = q;
349 }
350 /* end of chain */
351 /*r->next = NULL;*/
352
353 break;
354 case PBUF_RAM:
355 {
356 mem_size_t alloc_len = LWIP_MEM_ALIGN_SIZE(SIZEOF_STRUCT_PBUF + offset) + LWIP_MEM_ALIGN_SIZE(length);
357
358 /* bug #50040: Check for integer overflow when calculating alloc_len */
359 if (alloc_len < LWIP_MEM_ALIGN_SIZE(length)) {
360 return NULL;
361 }
362
363 /* If pbuf is to be allocated in RAM, allocate memory for it. */
364 p = (struct pbuf*)mem_malloc(alloc_len);
365 }
366
367 if (p == NULL) {
368 return NULL;
369 }
370 /* Set up internal structure of the pbuf. */
371 p->payload = LWIP_MEM_ALIGN((void *)((u8_t *)p + SIZEOF_STRUCT_PBUF + offset));
372 p->len = p->tot_len = length;
373 p->next = NULL;
374 p->type = type;
375
376 LWIP_ASSERT("pbuf_alloc: pbuf->payload properly aligned",
377 ((mem_ptr_t)p->payload % MEM_ALIGNMENT) == 0);
378 break;
379 /* pbuf references existing (non-volatile static constant) ROM payload? */
380 case PBUF_ROM:
381 /* pbuf references existing (externally allocated) RAM payload? */
382 case PBUF_REF:
383 /* only allocate memory for the pbuf structure */
384 p = (struct pbuf *)memp_malloc(MEMP_PBUF);
385 if (p == NULL) {
386 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
387 ("pbuf_alloc: Could not allocate MEMP_PBUF for PBUF_%s.\n",
388 (type == PBUF_ROM) ? "ROM" : "REF"));
389 return NULL;
390 }
391 /* caller must set this field properly, afterwards */
392 p->payload = NULL;
393 p->len = p->tot_len = length;
394 p->next = NULL;
395 p->type = type;
396 break;
397 default:
398 LWIP_ASSERT("pbuf_alloc: erroneous type", 0);
399 return NULL;
400 }
401 /* set reference count */
402 p->ref = 1;
403 /* set flags */
404 p->flags = 0;
405 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloc(length=%"U16_F") == %p\n", length, (void *)p));
406 return p;
407 }
408
409 #if LWIP_SUPPORT_CUSTOM_PBUF
410 /**
411 * @ingroup pbuf
412 * Initialize a custom pbuf (already allocated).
413 *
414 * @param l flag to define header size
415 * @param length size of the pbuf's payload
416 * @param type type of the pbuf (only used to treat the pbuf accordingly, as
417 * this function allocates no memory)
418 * @param p pointer to the custom pbuf to initialize (already allocated)
419 * @param payload_mem pointer to the buffer that is used for payload and headers,
420 * must be at least big enough to hold 'length' plus the header size,
421 * may be NULL if set later.
422 * ATTENTION: The caller is responsible for correct alignment of this buffer!!
423 * @param payload_mem_len the size of the 'payload_mem' buffer, must be at least
424 * big enough to hold 'length' plus the header size
425 */
426 struct pbuf*
pbuf_alloced_custom(pbuf_layer l,u16_t length,pbuf_type type,struct pbuf_custom * p,void * payload_mem,u16_t payload_mem_len)427 pbuf_alloced_custom(pbuf_layer l, u16_t length, pbuf_type type, struct pbuf_custom *p,
428 void *payload_mem, u16_t payload_mem_len)
429 {
430 u16_t offset;
431 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloced_custom(length=%"U16_F")\n", length));
432
433 /* determine header offset */
434 switch (l) {
435 case PBUF_TRANSPORT:
436 /* add room for transport (often TCP) layer header */
437 offset = PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN;
438 break;
439 case PBUF_IP:
440 /* add room for IP layer header */
441 offset = PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN + PBUF_IP_HLEN;
442 break;
443 case PBUF_LINK:
444 /* add room for link layer header */
445 offset = PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN;
446 break;
447 case PBUF_RAW_TX:
448 /* add room for encapsulating link layer headers (e.g. 802.11) */
449 offset = PBUF_LINK_ENCAPSULATION_HLEN;
450 break;
451 case PBUF_RAW:
452 offset = 0;
453 break;
454 default:
455 LWIP_ASSERT("pbuf_alloced_custom: bad pbuf layer", 0);
456 return NULL;
457 }
458
459 if (LWIP_MEM_ALIGN_SIZE(offset) + length > payload_mem_len) {
460 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_LEVEL_WARNING, ("pbuf_alloced_custom(length=%"U16_F") buffer too short\n", length));
461 return NULL;
462 }
463
464 p->pbuf.next = NULL;
465 if (payload_mem != NULL) {
466 p->pbuf.payload = (u8_t *)payload_mem + LWIP_MEM_ALIGN_SIZE(offset);
467 } else {
468 p->pbuf.payload = NULL;
469 }
470 p->pbuf.flags = PBUF_FLAG_IS_CUSTOM;
471 p->pbuf.len = p->pbuf.tot_len = length;
472 p->pbuf.type = type;
473 p->pbuf.ref = 1;
474 return &p->pbuf;
475 }
476 #endif /* LWIP_SUPPORT_CUSTOM_PBUF */
477
478 /**
479 * @ingroup pbuf
480 * Shrink a pbuf chain to a desired length.
481 *
482 * @param p pbuf to shrink.
483 * @param new_len desired new length of pbuf chain
484 *
485 * Depending on the desired length, the first few pbufs in a chain might
486 * be skipped and left unchanged. The new last pbuf in the chain will be
487 * resized, and any remaining pbufs will be freed.
488 *
489 * @note If the pbuf is ROM/REF, only the ->tot_len and ->len fields are adjusted.
490 * @note May not be called on a packet queue.
491 *
492 * @note Despite its name, pbuf_realloc cannot grow the size of a pbuf (chain).
493 */
494 void
pbuf_realloc(struct pbuf * p,u16_t new_len)495 pbuf_realloc(struct pbuf *p, u16_t new_len)
496 {
497 struct pbuf *q;
498 u16_t rem_len; /* remaining length */
499 s32_t grow;
500
501 LWIP_ASSERT("pbuf_realloc: p != NULL", p != NULL);
502 LWIP_ASSERT("pbuf_realloc: sane p->type", p->type == PBUF_POOL ||
503 p->type == PBUF_ROM ||
504 p->type == PBUF_RAM ||
505 p->type == PBUF_REF);
506
507 /* desired length larger than current length? */
508 if (new_len >= p->tot_len) {
509 /* enlarging not yet supported */
510 return;
511 }
512
513 /* the pbuf chain grows by (new_len - p->tot_len) bytes
514 * (which may be negative in case of shrinking) */
515 grow = new_len - p->tot_len;
516
517 /* first, step over any pbufs that should remain in the chain */
518 rem_len = new_len;
519 q = p;
520 /* should this pbuf be kept? */
521 while (rem_len > q->len) {
522 /* decrease remaining length by pbuf length */
523 rem_len -= q->len;
524 /* decrease total length indicator */
525 LWIP_ASSERT("grow < max_u16_t", grow < 0xffff);
526 q->tot_len += (u16_t)grow;
527 /* proceed to next pbuf in chain */
528 q = q->next;
529 LWIP_ASSERT("pbuf_realloc: q != NULL", q != NULL);
530 }
531 /* we have now reached the new last pbuf (in q) */
532 /* rem_len == desired length for pbuf q */
533
534 /* shrink allocated memory for PBUF_RAM */
535 /* (other types merely adjust their length fields */
536 if ((q->type == PBUF_RAM) && (rem_len != q->len)
537 #if LWIP_SUPPORT_CUSTOM_PBUF
538 && ((q->flags & PBUF_FLAG_IS_CUSTOM) == 0)
539 #endif /* LWIP_SUPPORT_CUSTOM_PBUF */
540 ) {
541 /* reallocate and adjust the length of the pbuf that will be split */
542 q = (struct pbuf *)mem_trim(q, (u16_t)((u8_t *)q->payload - (u8_t *)q) + rem_len);
543 LWIP_ASSERT("mem_trim returned q == NULL", q != NULL);
544 }
545 /* adjust length fields for new last pbuf */
546 q->len = rem_len;
547 q->tot_len = q->len;
548
549 /* any remaining pbufs in chain? */
550 if (q->next != NULL) {
551 /* free remaining pbufs in chain */
552 pbuf_free(q->next);
553 }
554 /* q is last packet in chain */
555 q->next = NULL;
556
557 }
558
559 /**
560 * Adjusts the payload pointer to hide or reveal headers in the payload.
561 * @see pbuf_header.
562 *
563 * @param p pbuf to change the header size.
564 * @param header_size_increment Number of bytes to increment header size.
565 * @param force Allow 'header_size_increment > 0' for PBUF_REF/PBUF_ROM types
566 *
567 * @return non-zero on failure, zero on success.
568 *
569 */
570 static u8_t
pbuf_header_impl(struct pbuf * p,s16_t header_size_increment,u8_t force)571 pbuf_header_impl(struct pbuf *p, s16_t header_size_increment, u8_t force)
572 {
573 u16_t type;
574 void *payload;
575 u16_t increment_magnitude;
576
577 LWIP_ASSERT("p != NULL", p != NULL);
578 if ((header_size_increment == 0) || (p == NULL)) {
579 return 0;
580 }
581
582 if (header_size_increment < 0) {
583 increment_magnitude = (u16_t)-header_size_increment;
584 /* Check that we aren't going to move off the end of the pbuf */
585 LWIP_ERROR("increment_magnitude <= p->len", (increment_magnitude <= p->len), return 1;);
586 } else {
587 increment_magnitude = (u16_t)header_size_increment;
588 /* Do not allow tot_len to wrap as a result. */
589 if ((u16_t)(increment_magnitude + p->tot_len) < increment_magnitude) {
590 return 1;
591 }
592 #if 0
593 /* Can't assert these as some callers speculatively call
594 pbuf_header() to see if it's OK. Will return 1 below instead. */
595 /* Check that we've got the correct type of pbuf to work with */
596 LWIP_ASSERT("p->type == PBUF_RAM || p->type == PBUF_POOL",
597 p->type == PBUF_RAM || p->type == PBUF_POOL);
598 /* Check that we aren't going to move off the beginning of the pbuf */
599 LWIP_ASSERT("p->payload - increment_magnitude >= p + SIZEOF_STRUCT_PBUF",
600 (u8_t *)p->payload - increment_magnitude >= (u8_t *)p + SIZEOF_STRUCT_PBUF);
601 #endif
602 }
603
604 type = p->type;
605 /* remember current payload pointer */
606 payload = p->payload;
607
608 /* pbuf types containing payloads? */
609 if (type == PBUF_RAM || type == PBUF_POOL) {
610 /* set new payload pointer */
611 p->payload = (u8_t *)p->payload - header_size_increment;
612 /* boundary check fails? */
613 if ((u8_t *)p->payload < (u8_t *)p + SIZEOF_STRUCT_PBUF) {
614 LWIP_DEBUGF( PBUF_DEBUG | LWIP_DBG_TRACE,
615 ("pbuf_header: failed as %p < %p (not enough space for new header size)\n",
616 (void *)p->payload, (void *)((u8_t *)p + SIZEOF_STRUCT_PBUF)));
617 /* restore old payload pointer */
618 p->payload = payload;
619 /* bail out unsuccessfully */
620 return 1;
621 }
622 /* pbuf types referring to external payloads? */
623 } else if (type == PBUF_REF || type == PBUF_ROM) {
624 /* hide a header in the payload? */
625 if ((header_size_increment < 0) && (increment_magnitude <= p->len)) {
626 /* increase payload pointer */
627 p->payload = (u8_t *)p->payload - header_size_increment;
628 } else if ((header_size_increment > 0) && force) {
629 p->payload = (u8_t *)p->payload - header_size_increment;
630 } else {
631 /* cannot expand payload to front (yet!)
632 * bail out unsuccessfully */
633 return 1;
634 }
635 } else {
636 /* Unknown type */
637 LWIP_ASSERT("bad pbuf type", 0);
638 return 1;
639 }
640 /* modify pbuf length fields */
641 p->len += header_size_increment;
642 p->tot_len += header_size_increment;
643
644 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_header: old %p new %p (%"S16_F")\n",
645 (void *)payload, (void *)p->payload, header_size_increment));
646
647 return 0;
648 }
649
650 /**
651 * Adjusts the payload pointer to hide or reveal headers in the payload.
652 *
653 * Adjusts the ->payload pointer so that space for a header
654 * (dis)appears in the pbuf payload.
655 *
656 * The ->payload, ->tot_len and ->len fields are adjusted.
657 *
658 * @param p pbuf to change the header size.
659 * @param header_size_increment Number of bytes to increment header size which
660 * increases the size of the pbuf. New space is on the front.
661 * (Using a negative value decreases the header size.)
662 * If hdr_size_inc is 0, this function does nothing and returns successful.
663 *
664 * PBUF_ROM and PBUF_REF type buffers cannot have their sizes increased, so
665 * the call will fail. A check is made that the increase in header size does
666 * not move the payload pointer in front of the start of the buffer.
667 * @return non-zero on failure, zero on success.
668 *
669 */
670 u8_t
pbuf_header(struct pbuf * p,s16_t header_size_increment)671 pbuf_header(struct pbuf *p, s16_t header_size_increment)
672 {
673 return pbuf_header_impl(p, header_size_increment, 0);
674 }
675
676 /**
677 * Same as pbuf_header but does not check if 'header_size > 0' is allowed.
678 * This is used internally only, to allow PBUF_REF for RX.
679 */
680 u8_t
pbuf_header_force(struct pbuf * p,s16_t header_size_increment)681 pbuf_header_force(struct pbuf *p, s16_t header_size_increment)
682 {
683 return pbuf_header_impl(p, header_size_increment, 1);
684 }
685
686 /** Similar to pbuf_header(-size) but de-refs header pbufs for (size >= p->len)
687 *
688 * @param q pbufs to operate on
689 * @param size The number of bytes to remove from the beginning of the pbuf list.
690 * While size >= p->len, pbufs are freed.
691 * ATTENTION: this is the opposite direction as @ref pbuf_header, but
692 * takes an u16_t not s16_t!
693 * @return the new head pbuf
694 */
695 struct pbuf*
pbuf_free_header(struct pbuf * q,u16_t size)696 pbuf_free_header(struct pbuf *q, u16_t size)
697 {
698 struct pbuf *p = q;
699 u16_t free_left = size;
700 while (free_left && p) {
701 s16_t free_len = (free_left > INT16_MAX ? INT16_MAX : (s16_t)free_left);
702 if (free_len >= p->len) {
703 struct pbuf *f = p;
704 free_left -= p->len;
705 p = p->next;
706 f->next = 0;
707 pbuf_free(f);
708 } else {
709 pbuf_header(p, -free_len);
710 free_left -= free_len;
711 }
712 }
713 return p;
714 }
715
716 /**
717 * @ingroup pbuf
718 * Dereference a pbuf chain or queue and deallocate any no-longer-used
719 * pbufs at the head of this chain or queue.
720 *
721 * Decrements the pbuf reference count. If it reaches zero, the pbuf is
722 * deallocated.
723 *
724 * For a pbuf chain, this is repeated for each pbuf in the chain,
725 * up to the first pbuf which has a non-zero reference count after
726 * decrementing. So, when all reference counts are one, the whole
727 * chain is free'd.
728 *
729 * @param p The pbuf (chain) to be dereferenced.
730 *
731 * @return the number of pbufs that were de-allocated
732 * from the head of the chain.
733 *
734 * @note MUST NOT be called on a packet queue (Not verified to work yet).
735 * @note the reference counter of a pbuf equals the number of pointers
736 * that refer to the pbuf (or into the pbuf).
737 *
738 * @internal examples:
739 *
740 * Assuming existing chains a->b->c with the following reference
741 * counts, calling pbuf_free(a) results in:
742 *
743 * 1->2->3 becomes ...1->3
744 * 3->3->3 becomes 2->3->3
745 * 1->1->2 becomes ......1
746 * 2->1->1 becomes 1->1->1
747 * 1->1->1 becomes .......
748 *
749 */
750 u8_t
pbuf_free(struct pbuf * p)751 pbuf_free(struct pbuf *p)
752 {
753 u16_t type;
754 struct pbuf *q;
755 u8_t count;
756
757 if (p == NULL) {
758 LWIP_ASSERT("p != NULL", p != NULL);
759 /* if assertions are disabled, proceed with debug output */
760 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
761 ("pbuf_free(p == NULL) was called.\n"));
762 return 0;
763 }
764 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_free(%p)\n", (void *)p));
765
766 PERF_START;
767
768 LWIP_ASSERT("pbuf_free: sane type",
769 p->type == PBUF_RAM || p->type == PBUF_ROM ||
770 p->type == PBUF_REF || p->type == PBUF_POOL);
771
772 count = 0;
773 /* de-allocate all consecutive pbufs from the head of the chain that
774 * obtain a zero reference count after decrementing*/
775 while (p != NULL) {
776 LWIP_PBUF_REF_T ref;
777 SYS_ARCH_DECL_PROTECT(old_level);
778 /* Since decrementing ref cannot be guaranteed to be a single machine operation
779 * we must protect it. We put the new ref into a local variable to prevent
780 * further protection. */
781 SYS_ARCH_PROTECT(old_level);
782 /* all pbufs in a chain are referenced at least once */
783 LWIP_ASSERT("pbuf_free: p->ref > 0", p->ref > 0);
784 /* decrease reference count (number of pointers to pbuf) */
785 ref = --(p->ref);
786 SYS_ARCH_UNPROTECT(old_level);
787 /* this pbuf is no longer referenced to? */
788 if (ref == 0) {
789 /* remember next pbuf in chain for next iteration */
790 q = p->next;
791 LWIP_DEBUGF( PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_free: deallocating %p\n", (void *)p));
792 type = p->type;
793 #if LWIP_SUPPORT_CUSTOM_PBUF
794 /* is this a custom pbuf? */
795 if ((p->flags & PBUF_FLAG_IS_CUSTOM) != 0) {
796 struct pbuf_custom *pc = (struct pbuf_custom*)p;
797 LWIP_ASSERT("pc->custom_free_function != NULL", pc->custom_free_function != NULL);
798 pc->custom_free_function(p);
799 } else
800 #endif /* LWIP_SUPPORT_CUSTOM_PBUF */
801 {
802 /* is this a pbuf from the pool? */
803 if (type == PBUF_POOL) {
804 memp_free(MEMP_PBUF_POOL, p);
805 /* is this a ROM or RAM referencing pbuf? */
806 } else if (type == PBUF_ROM || type == PBUF_REF) {
807 memp_free(MEMP_PBUF, p);
808 /* type == PBUF_RAM */
809 } else {
810 mem_free(p);
811 }
812 }
813 count++;
814 /* proceed to next pbuf */
815 p = q;
816 /* p->ref > 0, this pbuf is still referenced to */
817 /* (and so the remaining pbufs in chain as well) */
818 } else {
819 LWIP_DEBUGF( PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_free: %p has ref %"U16_F", ending here.\n", (void *)p, ref));
820 /* stop walking through the chain */
821 p = NULL;
822 }
823 }
824 PERF_STOP("pbuf_free");
825 /* return number of de-allocated pbufs */
826 return count;
827 }
828
829 /**
830 * Count number of pbufs in a chain
831 *
832 * @param p first pbuf of chain
833 * @return the number of pbufs in a chain
834 */
835 u16_t
pbuf_clen(const struct pbuf * p)836 pbuf_clen(const struct pbuf *p)
837 {
838 u16_t len;
839
840 len = 0;
841 while (p != NULL) {
842 ++len;
843 p = p->next;
844 }
845 return len;
846 }
847
848 /**
849 * @ingroup pbuf
850 * Increment the reference count of the pbuf.
851 *
852 * @param p pbuf to increase reference counter of
853 *
854 */
855 void
pbuf_ref(struct pbuf * p)856 pbuf_ref(struct pbuf *p)
857 {
858 /* pbuf given? */
859 if (p != NULL) {
860 SYS_ARCH_INC(p->ref, 1);
861 LWIP_ASSERT("pbuf ref overflow", p->ref > 0);
862 }
863 }
864
865 /**
866 * @ingroup pbuf
867 * Concatenate two pbufs (each may be a pbuf chain) and take over
868 * the caller's reference of the tail pbuf.
869 *
870 * @note The caller MAY NOT reference the tail pbuf afterwards.
871 * Use pbuf_chain() for that purpose.
872 *
873 * @see pbuf_chain()
874 */
875 void
pbuf_cat(struct pbuf * h,struct pbuf * t)876 pbuf_cat(struct pbuf *h, struct pbuf *t)
877 {
878 struct pbuf *p;
879
880 LWIP_ERROR("(h != NULL) && (t != NULL) (programmer violates API)",
881 ((h != NULL) && (t != NULL)), return;);
882
883 /* proceed to last pbuf of chain */
884 for (p = h; p->next != NULL; p = p->next) {
885 /* add total length of second chain to all totals of first chain */
886 p->tot_len += t->tot_len;
887 }
888 /* { p is last pbuf of first h chain, p->next == NULL } */
889 LWIP_ASSERT("p->tot_len == p->len (of last pbuf in chain)", p->tot_len == p->len);
890 LWIP_ASSERT("p->next == NULL", p->next == NULL);
891 /* add total length of second chain to last pbuf total of first chain */
892 p->tot_len += t->tot_len;
893 /* chain last pbuf of head (p) with first of tail (t) */
894 p->next = t;
895 /* p->next now references t, but the caller will drop its reference to t,
896 * so netto there is no change to the reference count of t.
897 */
898 }
899
900 /**
901 * @ingroup pbuf
902 * Chain two pbufs (or pbuf chains) together.
903 *
904 * The caller MUST call pbuf_free(t) once it has stopped
905 * using it. Use pbuf_cat() instead if you no longer use t.
906 *
907 * @param h head pbuf (chain)
908 * @param t tail pbuf (chain)
909 * @note The pbufs MUST belong to the same packet.
910 * @note MAY NOT be called on a packet queue.
911 *
912 * The ->tot_len fields of all pbufs of the head chain are adjusted.
913 * The ->next field of the last pbuf of the head chain is adjusted.
914 * The ->ref field of the first pbuf of the tail chain is adjusted.
915 *
916 */
917 void
pbuf_chain(struct pbuf * h,struct pbuf * t)918 pbuf_chain(struct pbuf *h, struct pbuf *t)
919 {
920 pbuf_cat(h, t);
921 /* t is now referenced by h */
922 pbuf_ref(t);
923 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_chain: %p references %p\n", (void *)h, (void *)t));
924 }
925
926 /**
927 * Dechains the first pbuf from its succeeding pbufs in the chain.
928 *
929 * Makes p->tot_len field equal to p->len.
930 * @param p pbuf to dechain
931 * @return remainder of the pbuf chain, or NULL if it was de-allocated.
932 * @note May not be called on a packet queue.
933 */
934 struct pbuf *
pbuf_dechain(struct pbuf * p)935 pbuf_dechain(struct pbuf *p)
936 {
937 struct pbuf *q;
938 u8_t tail_gone = 1;
939 /* tail */
940 q = p->next;
941 /* pbuf has successor in chain? */
942 if (q != NULL) {
943 /* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */
944 LWIP_ASSERT("p->tot_len == p->len + q->tot_len", q->tot_len == p->tot_len - p->len);
945 /* enforce invariant if assertion is disabled */
946 q->tot_len = p->tot_len - p->len;
947 /* decouple pbuf from remainder */
948 p->next = NULL;
949 /* total length of pbuf p is its own length only */
950 p->tot_len = p->len;
951 /* q is no longer referenced by p, free it */
952 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_dechain: unreferencing %p\n", (void *)q));
953 tail_gone = pbuf_free(q);
954 if (tail_gone > 0) {
955 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE,
956 ("pbuf_dechain: deallocated %p (as it is no longer referenced)\n", (void *)q));
957 }
958 /* return remaining tail or NULL if deallocated */
959 }
960 /* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */
961 LWIP_ASSERT("p->tot_len == p->len", p->tot_len == p->len);
962 return ((tail_gone > 0) ? NULL : q);
963 }
964
965 /**
966 * @ingroup pbuf
967 * Create PBUF_RAM copies of pbufs.
968 *
969 * Used to queue packets on behalf of the lwIP stack, such as
970 * ARP based queueing.
971 *
972 * @note You MUST explicitly use p = pbuf_take(p);
973 *
974 * @note Only one packet is copied, no packet queue!
975 *
976 * @param p_to pbuf destination of the copy
977 * @param p_from pbuf source of the copy
978 *
979 * @return ERR_OK if pbuf was copied
980 * ERR_ARG if one of the pbufs is NULL or p_to is not big
981 * enough to hold p_from
982 */
983 err_t
pbuf_copy(struct pbuf * p_to,const struct pbuf * p_from)984 pbuf_copy(struct pbuf *p_to, const struct pbuf *p_from)
985 {
986 u16_t offset_to=0, offset_from=0, len;
987
988 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_copy(%p, %p)\n",
989 (const void*)p_to, (const void*)p_from));
990
991 /* is the target big enough to hold the source? */
992 LWIP_ERROR("pbuf_copy: target not big enough to hold source", ((p_to != NULL) &&
993 (p_from != NULL) && (p_to->tot_len >= p_from->tot_len)), return ERR_ARG;);
994
995 /* iterate through pbuf chain */
996 do
997 {
998 /* copy one part of the original chain */
999 if ((p_to->len - offset_to) >= (p_from->len - offset_from)) {
1000 /* complete current p_from fits into current p_to */
1001 len = p_from->len - offset_from;
1002 } else {
1003 /* current p_from does not fit into current p_to */
1004 len = p_to->len - offset_to;
1005 }
1006 MEMCPY((u8_t*)p_to->payload + offset_to, (u8_t*)p_from->payload + offset_from, len);
1007 offset_to += len;
1008 offset_from += len;
1009 LWIP_ASSERT("offset_to <= p_to->len", offset_to <= p_to->len);
1010 LWIP_ASSERT("offset_from <= p_from->len", offset_from <= p_from->len);
1011 if (offset_from >= p_from->len) {
1012 /* on to next p_from (if any) */
1013 offset_from = 0;
1014 p_from = p_from->next;
1015 }
1016 if (offset_to == p_to->len) {
1017 /* on to next p_to (if any) */
1018 offset_to = 0;
1019 p_to = p_to->next;
1020 LWIP_ERROR("p_to != NULL", (p_to != NULL) || (p_from == NULL) , return ERR_ARG;);
1021 }
1022
1023 if ((p_from != NULL) && (p_from->len == p_from->tot_len)) {
1024 /* don't copy more than one packet! */
1025 LWIP_ERROR("pbuf_copy() does not allow packet queues!",
1026 (p_from->next == NULL), return ERR_VAL;);
1027 }
1028 if ((p_to != NULL) && (p_to->len == p_to->tot_len)) {
1029 /* don't copy more than one packet! */
1030 LWIP_ERROR("pbuf_copy() does not allow packet queues!",
1031 (p_to->next == NULL), return ERR_VAL;);
1032 }
1033 } while (p_from);
1034 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_copy: end of chain reached.\n"));
1035 return ERR_OK;
1036 }
1037
1038 /**
1039 * @ingroup pbuf
1040 * Copy (part of) the contents of a packet buffer
1041 * to an application supplied buffer.
1042 *
1043 * @param buf the pbuf from which to copy data
1044 * @param dataptr the application supplied buffer
1045 * @param len length of data to copy (dataptr must be big enough). No more
1046 * than buf->tot_len will be copied, irrespective of len
1047 * @param offset offset into the packet buffer from where to begin copying len bytes
1048 * @return the number of bytes copied, or 0 on failure
1049 */
1050 u16_t
pbuf_copy_partial(const struct pbuf * buf,void * dataptr,u16_t len,u16_t offset)1051 pbuf_copy_partial(const struct pbuf *buf, void *dataptr, u16_t len, u16_t offset)
1052 {
1053 const struct pbuf *p;
1054 u16_t left;
1055 u16_t buf_copy_len;
1056 u16_t copied_total = 0;
1057
1058 LWIP_ERROR("pbuf_copy_partial: invalid buf", (buf != NULL), return 0;);
1059 LWIP_ERROR("pbuf_copy_partial: invalid dataptr", (dataptr != NULL), return 0;);
1060
1061 left = 0;
1062
1063 if ((buf == NULL) || (dataptr == NULL)) {
1064 return 0;
1065 }
1066
1067 /* Note some systems use byte copy if dataptr or one of the pbuf payload pointers are unaligned. */
1068 for (p = buf; len != 0 && p != NULL; p = p->next) {
1069 if ((offset != 0) && (offset >= p->len)) {
1070 /* don't copy from this buffer -> on to the next */
1071 offset -= p->len;
1072 } else {
1073 /* copy from this buffer. maybe only partially. */
1074 buf_copy_len = p->len - offset;
1075 if (buf_copy_len > len) {
1076 buf_copy_len = len;
1077 }
1078 /* copy the necessary parts of the buffer */
1079 MEMCPY(&((char*)dataptr)[left], &((char*)p->payload)[offset], buf_copy_len);
1080 copied_total += buf_copy_len;
1081 left += buf_copy_len;
1082 len -= buf_copy_len;
1083 offset = 0;
1084 }
1085 }
1086 return copied_total;
1087 }
1088
1089 /**
1090 * @ingroup pbuf
1091 * Get part of a pbuf's payload as contiguous memory. The returned memory is
1092 * either a pointer into the pbuf's payload or, if split over multiple pbufs,
1093 * a copy into the user-supplied buffer.
1094 *
1095 * @param p the pbuf from which to copy data
1096 * @param buffer the application supplied buffer
1097 * @param bufsize size of the application supplied buffer
1098 * @param len length of data to copy (dataptr must be big enough). No more
1099 * than buf->tot_len will be copied, irrespective of len
1100 * @param offset offset into the packet buffer from where to begin copying len bytes
1101 * @return the number of bytes copied, or 0 on failure
1102 */
1103 void *
pbuf_get_contiguous(const struct pbuf * p,void * buffer,size_t bufsize,u16_t len,u16_t offset)1104 pbuf_get_contiguous(const struct pbuf *p, void *buffer, size_t bufsize, u16_t len, u16_t offset)
1105 {
1106 const struct pbuf *q;
1107
1108 LWIP_ERROR("pbuf_get_contiguous: invalid buf", (p != NULL), return NULL;);
1109 LWIP_ERROR("pbuf_get_contiguous: invalid dataptr", (buffer != NULL), return NULL;);
1110 LWIP_ERROR("pbuf_get_contiguous: invalid dataptr", (bufsize >= len), return NULL;);
1111
1112 for (q = p; q != NULL; q = q->next) {
1113 if ((offset != 0) && (offset >= q->len)) {
1114 /* don't copy from this buffer -> on to the next */
1115 offset -= q->len;
1116 } else {
1117 if (q->len >= (offset + len)) {
1118 /* all data in this pbuf, return zero-copy */
1119 return (u8_t*)q->payload + offset;
1120 }
1121 /* need to copy */
1122 if (pbuf_copy_partial(q, buffer, len, offset) != len) {
1123 /* copying failed: pbuf is too short */
1124 return NULL;
1125 }
1126 return buffer;
1127 }
1128 }
1129 /* pbuf is too short (offset does not fit in) */
1130 return NULL;
1131 }
1132
1133 #if LWIP_TCP && TCP_QUEUE_OOSEQ && LWIP_WND_SCALE
1134 /**
1135 * This method modifies a 'pbuf chain', so that its total length is
1136 * smaller than 64K. The remainder of the original pbuf chain is stored
1137 * in *rest.
1138 * This function never creates new pbufs, but splits an existing chain
1139 * in two parts. The tot_len of the modified packet queue will likely be
1140 * smaller than 64K.
1141 * 'packet queues' are not supported by this function.
1142 *
1143 * @param p the pbuf queue to be split
1144 * @param rest pointer to store the remainder (after the first 64K)
1145 */
pbuf_split_64k(struct pbuf * p,struct pbuf ** rest)1146 void pbuf_split_64k(struct pbuf *p, struct pbuf **rest)
1147 {
1148 *rest = NULL;
1149 if ((p != NULL) && (p->next != NULL)) {
1150 u16_t tot_len_front = p->len;
1151 struct pbuf *i = p;
1152 struct pbuf *r = p->next;
1153
1154 /* continue until the total length (summed up as u16_t) overflows */
1155 while ((r != NULL) && ((u16_t)(tot_len_front + r->len) > tot_len_front)) {
1156 tot_len_front += r->len;
1157 i = r;
1158 r = r->next;
1159 }
1160 /* i now points to last packet of the first segment. Set next
1161 pointer to NULL */
1162 i->next = NULL;
1163
1164 if (r != NULL) {
1165 /* Update the tot_len field in the first part */
1166 for (i = p; i != NULL; i = i->next) {
1167 i->tot_len -= r->tot_len;
1168 LWIP_ASSERT("tot_len/len mismatch in last pbuf",
1169 (i->next != NULL) || (i->tot_len == i->len));
1170 }
1171 if (p->flags & PBUF_FLAG_TCP_FIN) {
1172 r->flags |= PBUF_FLAG_TCP_FIN;
1173 }
1174
1175 /* tot_len field in rest does not need modifications */
1176 /* reference counters do not need modifications */
1177 *rest = r;
1178 }
1179 }
1180 }
1181 #endif /* LWIP_TCP && TCP_QUEUE_OOSEQ && LWIP_WND_SCALE */
1182
1183 /* Actual implementation of pbuf_skip() but returning const pointer... */
1184 static const struct pbuf*
pbuf_skip_const(const struct pbuf * in,u16_t in_offset,u16_t * out_offset)1185 pbuf_skip_const(const struct pbuf* in, u16_t in_offset, u16_t* out_offset)
1186 {
1187 u16_t offset_left = in_offset;
1188 const struct pbuf* q = in;
1189
1190 /* get the correct pbuf */
1191 while ((q != NULL) && (q->len <= offset_left)) {
1192 offset_left -= q->len;
1193 q = q->next;
1194 }
1195 if (out_offset != NULL) {
1196 *out_offset = offset_left;
1197 }
1198 return q;
1199 }
1200
1201 /**
1202 * @ingroup pbuf
1203 * Skip a number of bytes at the start of a pbuf
1204 *
1205 * @param in input pbuf
1206 * @param in_offset offset to skip
1207 * @param out_offset resulting offset in the returned pbuf
1208 * @return the pbuf in the queue where the offset is
1209 */
1210 struct pbuf*
pbuf_skip(struct pbuf * in,u16_t in_offset,u16_t * out_offset)1211 pbuf_skip(struct pbuf* in, u16_t in_offset, u16_t* out_offset)
1212 {
1213 const struct pbuf* out = pbuf_skip_const(in, in_offset, out_offset);
1214 return LWIP_CONST_CAST(struct pbuf*, out);
1215 }
1216
1217 /**
1218 * @ingroup pbuf
1219 * Copy application supplied data into a pbuf.
1220 * This function can only be used to copy the equivalent of buf->tot_len data.
1221 *
1222 * @param buf pbuf to fill with data
1223 * @param dataptr application supplied data buffer
1224 * @param len length of the application supplied data buffer
1225 *
1226 * @return ERR_OK if successful, ERR_MEM if the pbuf is not big enough
1227 */
1228 err_t
pbuf_take(struct pbuf * buf,const void * dataptr,u16_t len)1229 pbuf_take(struct pbuf *buf, const void *dataptr, u16_t len)
1230 {
1231 struct pbuf *p;
1232 u16_t buf_copy_len;
1233 u16_t total_copy_len = len;
1234 u16_t copied_total = 0;
1235
1236 LWIP_ERROR("pbuf_take: invalid buf", (buf != NULL), return ERR_ARG;);
1237 LWIP_ERROR("pbuf_take: invalid dataptr", (dataptr != NULL), return ERR_ARG;);
1238 LWIP_ERROR("pbuf_take: buf not large enough", (buf->tot_len >= len), return ERR_MEM;);
1239
1240 if ((buf == NULL) || (dataptr == NULL) || (buf->tot_len < len)) {
1241 return ERR_ARG;
1242 }
1243
1244 /* Note some systems use byte copy if dataptr or one of the pbuf payload pointers are unaligned. */
1245 for (p = buf; total_copy_len != 0; p = p->next) {
1246 LWIP_ASSERT("pbuf_take: invalid pbuf", p != NULL);
1247 buf_copy_len = total_copy_len;
1248 if (buf_copy_len > p->len) {
1249 /* this pbuf cannot hold all remaining data */
1250 buf_copy_len = p->len;
1251 }
1252 /* copy the necessary parts of the buffer */
1253 MEMCPY(p->payload, &((const char*)dataptr)[copied_total], buf_copy_len);
1254 total_copy_len -= buf_copy_len;
1255 copied_total += buf_copy_len;
1256 }
1257 LWIP_ASSERT("did not copy all data", total_copy_len == 0 && copied_total == len);
1258 return ERR_OK;
1259 }
1260
1261 /**
1262 * @ingroup pbuf
1263 * Same as pbuf_take() but puts data at an offset
1264 *
1265 * @param buf pbuf to fill with data
1266 * @param dataptr application supplied data buffer
1267 * @param len length of the application supplied data buffer
1268 * @param offset offset in pbuf where to copy dataptr to
1269 *
1270 * @return ERR_OK if successful, ERR_MEM if the pbuf is not big enough
1271 */
1272 err_t
pbuf_take_at(struct pbuf * buf,const void * dataptr,u16_t len,u16_t offset)1273 pbuf_take_at(struct pbuf *buf, const void *dataptr, u16_t len, u16_t offset)
1274 {
1275 u16_t target_offset;
1276 struct pbuf* q = pbuf_skip(buf, offset, &target_offset);
1277
1278 /* return requested data if pbuf is OK */
1279 if ((q != NULL) && (q->tot_len >= target_offset + len)) {
1280 u16_t remaining_len = len;
1281 const u8_t* src_ptr = (const u8_t*)dataptr;
1282 /* copy the part that goes into the first pbuf */
1283 u16_t first_copy_len = LWIP_MIN(q->len - target_offset, len);
1284 MEMCPY(((u8_t*)q->payload) + target_offset, dataptr, first_copy_len);
1285 remaining_len -= first_copy_len;
1286 src_ptr += first_copy_len;
1287 if (remaining_len > 0) {
1288 return pbuf_take(q->next, src_ptr, remaining_len);
1289 }
1290 return ERR_OK;
1291 }
1292 return ERR_MEM;
1293 }
1294
1295 /**
1296 * @ingroup pbuf
1297 * Creates a single pbuf out of a queue of pbufs.
1298 *
1299 * @remark: Either the source pbuf 'p' is freed by this function or the original
1300 * pbuf 'p' is returned, therefore the caller has to check the result!
1301 *
1302 * @param p the source pbuf
1303 * @param layer pbuf_layer of the new pbuf
1304 *
1305 * @return a new, single pbuf (p->next is NULL)
1306 * or the old pbuf if allocation fails
1307 */
1308 struct pbuf*
pbuf_coalesce(struct pbuf * p,pbuf_layer layer)1309 pbuf_coalesce(struct pbuf *p, pbuf_layer layer)
1310 {
1311 struct pbuf *q;
1312 err_t err;
1313 if (p->next == NULL) {
1314 return p;
1315 }
1316 q = pbuf_alloc(layer, p->tot_len, PBUF_RAM);
1317 if (q == NULL) {
1318 /* @todo: what do we do now? */
1319 return p;
1320 }
1321 err = pbuf_copy(q, p);
1322 LWIP_UNUSED_ARG(err); /* in case of LWIP_NOASSERT */
1323 LWIP_ASSERT("pbuf_copy failed", err == ERR_OK);
1324 pbuf_free(p);
1325 return q;
1326 }
1327
1328 #if LWIP_CHECKSUM_ON_COPY
1329 /**
1330 * Copies data into a single pbuf (*not* into a pbuf queue!) and updates
1331 * the checksum while copying
1332 *
1333 * @param p the pbuf to copy data into
1334 * @param start_offset offset of p->payload where to copy the data to
1335 * @param dataptr data to copy into the pbuf
1336 * @param len length of data to copy into the pbuf
1337 * @param chksum pointer to the checksum which is updated
1338 * @return ERR_OK if successful, another error if the data does not fit
1339 * within the (first) pbuf (no pbuf queues!)
1340 */
1341 err_t
pbuf_fill_chksum(struct pbuf * p,u16_t start_offset,const void * dataptr,u16_t len,u16_t * chksum)1342 pbuf_fill_chksum(struct pbuf *p, u16_t start_offset, const void *dataptr,
1343 u16_t len, u16_t *chksum)
1344 {
1345 u32_t acc;
1346 u16_t copy_chksum;
1347 char *dst_ptr;
1348 LWIP_ASSERT("p != NULL", p != NULL);
1349 LWIP_ASSERT("dataptr != NULL", dataptr != NULL);
1350 LWIP_ASSERT("chksum != NULL", chksum != NULL);
1351 LWIP_ASSERT("len != 0", len != 0);
1352
1353 if ((start_offset >= p->len) || (start_offset + len > p->len)) {
1354 return ERR_ARG;
1355 }
1356
1357 dst_ptr = ((char*)p->payload) + start_offset;
1358 copy_chksum = LWIP_CHKSUM_COPY(dst_ptr, dataptr, len);
1359 if ((start_offset & 1) != 0) {
1360 copy_chksum = SWAP_BYTES_IN_WORD(copy_chksum);
1361 }
1362 acc = *chksum;
1363 acc += copy_chksum;
1364 *chksum = FOLD_U32T(acc);
1365 return ERR_OK;
1366 }
1367 #endif /* LWIP_CHECKSUM_ON_COPY */
1368
1369 /**
1370 * @ingroup pbuf
1371 * Get one byte from the specified position in a pbuf
1372 * WARNING: returns zero for offset >= p->tot_len
1373 *
1374 * @param p pbuf to parse
1375 * @param offset offset into p of the byte to return
1376 * @return byte at an offset into p OR ZERO IF 'offset' >= p->tot_len
1377 */
1378 u8_t
pbuf_get_at(const struct pbuf * p,u16_t offset)1379 pbuf_get_at(const struct pbuf* p, u16_t offset)
1380 {
1381 int ret = pbuf_try_get_at(p, offset);
1382 if (ret >= 0) {
1383 return (u8_t)ret;
1384 }
1385 return 0;
1386 }
1387
1388 /**
1389 * @ingroup pbuf
1390 * Get one byte from the specified position in a pbuf
1391 *
1392 * @param p pbuf to parse
1393 * @param offset offset into p of the byte to return
1394 * @return byte at an offset into p [0..0xFF] OR negative if 'offset' >= p->tot_len
1395 */
1396 int
pbuf_try_get_at(const struct pbuf * p,u16_t offset)1397 pbuf_try_get_at(const struct pbuf* p, u16_t offset)
1398 {
1399 u16_t q_idx;
1400 const struct pbuf* q = pbuf_skip_const(p, offset, &q_idx);
1401
1402 /* return requested data if pbuf is OK */
1403 if ((q != NULL) && (q->len > q_idx)) {
1404 return ((u8_t*)q->payload)[q_idx];
1405 }
1406 return -1;
1407 }
1408
1409 /**
1410 * @ingroup pbuf
1411 * Put one byte to the specified position in a pbuf
1412 * WARNING: silently ignores offset >= p->tot_len
1413 *
1414 * @param p pbuf to fill
1415 * @param offset offset into p of the byte to write
1416 * @param data byte to write at an offset into p
1417 */
1418 void
pbuf_put_at(struct pbuf * p,u16_t offset,u8_t data)1419 pbuf_put_at(struct pbuf* p, u16_t offset, u8_t data)
1420 {
1421 u16_t q_idx;
1422 struct pbuf* q = pbuf_skip(p, offset, &q_idx);
1423
1424 /* write requested data if pbuf is OK */
1425 if ((q != NULL) && (q->len > q_idx)) {
1426 ((u8_t*)q->payload)[q_idx] = data;
1427 }
1428 }
1429
1430 /**
1431 * @ingroup pbuf
1432 * Compare pbuf contents at specified offset with memory s2, both of length n
1433 *
1434 * @param p pbuf to compare
1435 * @param offset offset into p at which to start comparing
1436 * @param s2 buffer to compare
1437 * @param n length of buffer to compare
1438 * @return zero if equal, nonzero otherwise
1439 * (0xffff if p is too short, diffoffset+1 otherwise)
1440 */
1441 u16_t
pbuf_memcmp(const struct pbuf * p,u16_t offset,const void * s2,u16_t n)1442 pbuf_memcmp(const struct pbuf* p, u16_t offset, const void* s2, u16_t n)
1443 {
1444 u16_t start = offset;
1445 const struct pbuf* q = p;
1446 u16_t i;
1447
1448 /* pbuf long enough to perform check? */
1449 if(p->tot_len < (offset + n)) {
1450 return 0xffff;
1451 }
1452
1453 /* get the correct pbuf from chain. We know it succeeds because of p->tot_len check above. */
1454 while ((q != NULL) && (q->len <= start)) {
1455 start -= q->len;
1456 q = q->next;
1457 }
1458
1459 /* return requested data if pbuf is OK */
1460 for (i = 0; i < n; i++) {
1461 /* We know pbuf_get_at() succeeds because of p->tot_len check above. */
1462 u8_t a = pbuf_get_at(q, start + i);
1463 u8_t b = ((const u8_t*)s2)[i];
1464 if (a != b) {
1465 return i+1;
1466 }
1467 }
1468 return 0;
1469 }
1470
1471 /**
1472 * @ingroup pbuf
1473 * Find occurrence of mem (with length mem_len) in pbuf p, starting at offset
1474 * start_offset.
1475 *
1476 * @param p pbuf to search, maximum length is 0xFFFE since 0xFFFF is used as
1477 * return value 'not found'
1478 * @param mem search for the contents of this buffer
1479 * @param mem_len length of 'mem'
1480 * @param start_offset offset into p at which to start searching
1481 * @return 0xFFFF if substr was not found in p or the index where it was found
1482 */
1483 u16_t
pbuf_memfind(const struct pbuf * p,const void * mem,u16_t mem_len,u16_t start_offset)1484 pbuf_memfind(const struct pbuf* p, const void* mem, u16_t mem_len, u16_t start_offset)
1485 {
1486 u16_t i;
1487 u16_t max = p->tot_len - mem_len;
1488 if (p->tot_len >= mem_len + start_offset) {
1489 for (i = start_offset; i <= max; i++) {
1490 u16_t plus = pbuf_memcmp(p, i, mem, mem_len);
1491 if (plus == 0) {
1492 return i;
1493 }
1494 }
1495 }
1496 return 0xFFFF;
1497 }
1498
1499 /**
1500 * Find occurrence of substr with length substr_len in pbuf p, start at offset
1501 * start_offset
1502 * WARNING: in contrast to strstr(), this one does not stop at the first \0 in
1503 * the pbuf/source string!
1504 *
1505 * @param p pbuf to search, maximum length is 0xFFFE since 0xFFFF is used as
1506 * return value 'not found'
1507 * @param substr string to search for in p, maximum length is 0xFFFE
1508 * @return 0xFFFF if substr was not found in p or the index where it was found
1509 */
1510 u16_t
pbuf_strstr(const struct pbuf * p,const char * substr)1511 pbuf_strstr(const struct pbuf* p, const char* substr)
1512 {
1513 size_t substr_len;
1514 if ((substr == NULL) || (substr[0] == 0) || (p->tot_len == 0xFFFF)) {
1515 return 0xFFFF;
1516 }
1517 substr_len = strlen(substr);
1518 if (substr_len >= 0xFFFF) {
1519 return 0xFFFF;
1520 }
1521 return pbuf_memfind(p, substr, (u16_t)substr_len, 0);
1522 }
1523