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 (at) 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 } 1157
