Some quick code to use UDP-only (no TCP) with mBed. Echos received packets and sends packets when a button is pressed
pbuf.c
00001 /** 00002 * @file 00003 * Packet buffer management 00004 * 00005 * Packets are built from the pbuf data structure. It supports dynamic 00006 * memory allocation for packet contents or can reference externally 00007 * managed packet contents both in RAM and ROM. Quick allocation for 00008 * incoming packets is provided through pools with fixed sized pbufs. 00009 * 00010 * A packet may span over multiple pbufs, chained as a singly linked 00011 * list. This is called a "pbuf chain". 00012 * 00013 * Multiple packets may be queued, also using this singly linked list. 00014 * This is called a "packet queue". 00015 * 00016 * So, a packet queue consists of one or more pbuf chains, each of 00017 * which consist of one or more pbufs. CURRENTLY, PACKET QUEUES ARE 00018 * NOT SUPPORTED!!! Use helper structs to queue multiple packets. 00019 * 00020 * The differences between a pbuf chain and a packet queue are very 00021 * precise but subtle. 00022 * 00023 * The last pbuf of a packet has a ->tot_len field that equals the 00024 * ->len field. It can be found by traversing the list. If the last 00025 * pbuf of a packet has a ->next field other than NULL, more packets 00026 * are on the queue. 00027 * 00028 * Therefore, looping through a pbuf of a single packet, has an 00029 * loop end condition (tot_len == p->len), NOT (next == NULL). 00030 */ 00031 00032 /* 00033 * Copyright (c) 2001-2004 Swedish Institute of Computer Science. 00034 * All rights reserved. 00035 * 00036 * Redistribution and use in source and binary forms, with or without modification, 00037 * are permitted provided that the following conditions are met: 00038 * 00039 * 1. Redistributions of source code must retain the above copyright notice, 00040 * this list of conditions and the following disclaimer. 00041 * 2. Redistributions in binary form must reproduce the above copyright notice, 00042 * this list of conditions and the following disclaimer in the documentation 00043 * and/or other materials provided with the distribution. 00044 * 3. The name of the author may not be used to endorse or promote products 00045 * derived from this software without specific prior written permission. 00046 * 00047 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 00048 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 00049 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 00050 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 00051 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 00052 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 00053 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 00054 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 00055 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 00056 * OF SUCH DAMAGE. 00057 * 00058 * This file is part of the lwIP TCP/IP stack. 00059 * 00060 * Author: Adam Dunkels <adam@sics.se> 00061 * 00062 */ 00063 00064 #include "lwip/opt.h" 00065 00066 #include "lwip/stats.h" 00067 #include "lwip/def.h" 00068 #include "lwip/mem.h" 00069 #include "lwip/memp.h" 00070 #include "lwip/pbuf.h" 00071 #include "lwip/sys.h" 00072 #include "arch/perf.h" 00073 #if TCP_QUEUE_OOSEQ 00074 #include "lwip/tcp.h" 00075 #endif 00076 00077 #include <string.h> 00078 00079 #define SIZEOF_STRUCT_PBUF LWIP_MEM_ALIGN_SIZE(sizeof(struct pbuf)) 00080 /* Since the pool is created in memp, PBUF_POOL_BUFSIZE will be automatically 00081 aligned there. Therefore, PBUF_POOL_BUFSIZE_ALIGNED can be used here. */ 00082 #define PBUF_POOL_BUFSIZE_ALIGNED LWIP_MEM_ALIGN_SIZE(PBUF_POOL_BUFSIZE) 00083 00084 #if TCP_QUEUE_OOSEQ 00085 #define ALLOC_POOL_PBUF(p) do { (p) = alloc_pool_pbuf(); } while (0) 00086 #else 00087 #define ALLOC_POOL_PBUF(p) do { (p) = memp_malloc(MEMP_PBUF_POOL); } while (0) 00088 #endif 00089 00090 00091 #if TCP_QUEUE_OOSEQ 00092 /** 00093 * Attempt to reclaim some memory from queued out-of-sequence TCP segments 00094 * if we run out of pool pbufs. It's better to give priority to new packets 00095 * if we're running out. 00096 * 00097 * @return the allocated pbuf. 00098 */ 00099 static struct pbuf * 00100 alloc_pool_pbuf(void) 00101 { 00102 struct tcp_pcb *pcb; 00103 struct pbuf *p; 00104 00105 retry: 00106 p = (struct pbuf *)memp_malloc(MEMP_PBUF_POOL); 00107 if (NULL == p) { 00108 for (pcb=tcp_active_pcbs; NULL != pcb; pcb = pcb->next) { 00109 if (NULL != pcb->ooseq) { 00110 tcp_segs_free(pcb->ooseq); 00111 pcb->ooseq = NULL; 00112 goto retry; 00113 } 00114 } 00115 } 00116 return p; 00117 } 00118 #endif /* TCP_QUEUE_OOSEQ */ 00119 00120 /** 00121 * Allocates a pbuf of the given type (possibly a chain for PBUF_POOL type). 00122 * 00123 * The actual memory allocated for the pbuf is determined by the 00124 * layer at which the pbuf is allocated and the requested size 00125 * (from the size parameter). 00126 * 00127 * @param layer flag to define header size 00128 * @param length size of the pbuf's payload 00129 * @param type this parameter decides how and where the pbuf 00130 * should be allocated as follows: 00131 * 00132 * - PBUF_RAM: buffer memory for pbuf is allocated as one large 00133 * chunk. This includes protocol headers as well. 00134 * - PBUF_ROM: no buffer memory is allocated for the pbuf, even for 00135 * protocol headers. Additional headers must be prepended 00136 * by allocating another pbuf and chain in to the front of 00137 * the ROM pbuf. It is assumed that the memory used is really 00138 * similar to ROM in that it is immutable and will not be 00139 * changed. Memory which is dynamic should generally not 00140 * be attached to PBUF_ROM pbufs. Use PBUF_REF instead. 00141 * - PBUF_REF: no buffer memory is allocated for the pbuf, even for 00142 * protocol headers. It is assumed that the pbuf is only 00143 * being used in a single thread. If the pbuf gets queued, 00144 * then pbuf_take should be called to copy the buffer. 00145 * - PBUF_POOL: the pbuf is allocated as a pbuf chain, with pbufs from 00146 * the pbuf pool that is allocated during pbuf_init(). 00147 * 00148 * @return the allocated pbuf. If multiple pbufs where allocated, this 00149 * is the first pbuf of a pbuf chain. 00150 */ 00151 struct pbuf * 00152 pbuf_alloc(pbuf_layer layer, u16_t length, pbuf_type type) 00153 { 00154 struct pbuf *p, *q, *r; 00155 u16_t offset; 00156 s32_t rem_len; /* remaining length */ 00157 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE | 3, ("pbuf_alloc(length=%"U16_F")\n", length)); 00158 00159 /* determine header offset */ 00160 offset = 0; 00161 switch (layer) { 00162 case PBUF_TRANSPORT: 00163 /* add room for transport (often TCP) layer header */ 00164 offset += PBUF_TRANSPORT_HLEN; 00165 /* FALLTHROUGH */ 00166 case PBUF_IP: 00167 /* add room for IP layer header */ 00168 offset += PBUF_IP_HLEN; 00169 /* FALLTHROUGH */ 00170 case PBUF_LINK: 00171 /* add room for link layer header */ 00172 offset += PBUF_LINK_HLEN; 00173 break; 00174 case PBUF_RAW: 00175 break; 00176 default: 00177 LWIP_ASSERT("pbuf_alloc: bad pbuf layer", 0); 00178 return NULL; 00179 } 00180 00181 switch (type) { 00182 case PBUF_POOL: 00183 /* allocate head of pbuf chain into p */ 00184 ALLOC_POOL_PBUF(p); 00185 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE | 3, ("pbuf_alloc: allocated pbuf %p\n", (void *)p)); 00186 if (p == NULL) { 00187 return NULL; 00188 } 00189 p->type = type; 00190 p->next = NULL; 00191 00192 /* make the payload pointer point 'offset' bytes into pbuf data memory */ 00193 p->payload = LWIP_MEM_ALIGN((void *)((u8_t *)p + (SIZEOF_STRUCT_PBUF + offset))); 00194 LWIP_ASSERT("pbuf_alloc: pbuf p->payload properly aligned", 00195 ((mem_ptr_t)p->payload % MEM_ALIGNMENT) == 0); 00196 /* the total length of the pbuf chain is the requested size */ 00197 p->tot_len = length; 00198 /* set the length of the first pbuf in the chain */ 00199 p->len = LWIP_MIN(length, PBUF_POOL_BUFSIZE_ALIGNED - LWIP_MEM_ALIGN_SIZE(offset)); 00200 LWIP_ASSERT("check p->payload + p->len does not overflow pbuf", 00201 ((u8_t*)p->payload + p->len <= 00202 (u8_t*)p + SIZEOF_STRUCT_PBUF + PBUF_POOL_BUFSIZE_ALIGNED)); 00203 LWIP_ASSERT("PBUF_POOL_BUFSIZE must be bigger than MEM_ALIGNMENT", 00204 (PBUF_POOL_BUFSIZE_ALIGNED - LWIP_MEM_ALIGN_SIZE(offset)) > 0 ); 00205 /* set reference count (needed here in case we fail) */ 00206 p->ref = 1; 00207 00208 /* now allocate the tail of the pbuf chain */ 00209 00210 /* remember first pbuf for linkage in next iteration */ 00211 r = p; 00212 /* remaining length to be allocated */ 00213 rem_len = length - p->len; 00214 /* any remaining pbufs to be allocated? */ 00215 while (rem_len > 0) { 00216 ALLOC_POOL_PBUF(q); 00217 if (q == NULL) { 00218 /* free chain so far allocated */ 00219 pbuf_free(p); 00220 /* bail out unsuccesfully */ 00221 return NULL; 00222 } 00223 q->type = type; 00224 q->flags = 0; 00225 q->next = NULL; 00226 /* make previous pbuf point to this pbuf */ 00227 r->next = q; 00228 /* set total length of this pbuf and next in chain */ 00229 LWIP_ASSERT("rem_len < max_u16_t", rem_len < 0xffff); 00230 q->tot_len = (u16_t)rem_len; 00231 /* this pbuf length is pool size, unless smaller sized tail */ 00232 q->len = LWIP_MIN((u16_t)rem_len, PBUF_POOL_BUFSIZE_ALIGNED); 00233 q->payload = (void *)((u8_t *)q + SIZEOF_STRUCT_PBUF); 00234 LWIP_ASSERT("pbuf_alloc: pbuf q->payload properly aligned", 00235 ((mem_ptr_t)q->payload % MEM_ALIGNMENT) == 0); 00236 LWIP_ASSERT("check p->payload + p->len does not overflow pbuf", 00237 ((u8_t*)p->payload + p->len <= 00238 (u8_t*)p + SIZEOF_STRUCT_PBUF + PBUF_POOL_BUFSIZE_ALIGNED)); 00239 q->ref = 1; 00240 /* calculate remaining length to be allocated */ 00241 rem_len -= q->len; 00242 /* remember this pbuf for linkage in next iteration */ 00243 r = q; 00244 } 00245 /* end of chain */ 00246 /*r->next = NULL;*/ 00247 00248 break; 00249 case PBUF_RAM: 00250 /* If pbuf is to be allocated in RAM, allocate memory for it. */ 00251 p = (struct pbuf*)mem_malloc(LWIP_MEM_ALIGN_SIZE(SIZEOF_STRUCT_PBUF + offset) + LWIP_MEM_ALIGN_SIZE(length)); 00252 if (p == NULL) { 00253 return NULL; 00254 } 00255 /* Set up internal structure of the pbuf. */ 00256 p->payload = LWIP_MEM_ALIGN((void *)((u8_t *)p + SIZEOF_STRUCT_PBUF + offset)); 00257 p->len = p->tot_len = length; 00258 p->next = NULL; 00259 p->type = type; 00260 00261 LWIP_ASSERT("pbuf_alloc: pbuf->payload properly aligned", 00262 ((mem_ptr_t)p->payload % MEM_ALIGNMENT) == 0); 00263 break; 00264 /* pbuf references existing (non-volatile static constant) ROM payload? */ 00265 case PBUF_ROM: 00266 /* pbuf references existing (externally allocated) RAM payload? */ 00267 case PBUF_REF: 00268 /* only allocate memory for the pbuf structure */ 00269 p = (struct pbuf *)memp_malloc(MEMP_PBUF); 00270 if (p == NULL) { 00271 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE | 2, ("pbuf_alloc: Could not allocate MEMP_PBUF for PBUF_%s.\n", 00272 (type == PBUF_ROM) ? "ROM" : "REF")); 00273 return NULL; 00274 } 00275 /* caller must set this field properly, afterwards */ 00276 p->payload = NULL; 00277 p->len = p->tot_len = length; 00278 p->next = NULL; 00279 p->type = type; 00280 break; 00281 default: 00282 LWIP_ASSERT("pbuf_alloc: erroneous type", 0); 00283 return NULL; 00284 } 00285 /* set reference count */ 00286 p->ref = 1; 00287 /* set flags */ 00288 p->flags = 0; 00289 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE | 3, ("pbuf_alloc(length=%"U16_F") == %p\n", length, (void *)p)); 00290 return p; 00291 } 00292 00293 00294 /** 00295 * Shrink a pbuf chain to a desired length. 00296 * 00297 * @param p pbuf to shrink. 00298 * @param new_len desired new length of pbuf chain 00299 * 00300 * Depending on the desired length, the first few pbufs in a chain might 00301 * be skipped and left unchanged. The new last pbuf in the chain will be 00302 * resized, and any remaining pbufs will be freed. 00303 * 00304 * @note If the pbuf is ROM/REF, only the ->tot_len and ->len fields are adjusted. 00305 * @note May not be called on a packet queue. 00306 * 00307 * @note Despite its name, pbuf_realloc cannot grow the size of a pbuf (chain). 00308 */ 00309 void 00310 pbuf_realloc(struct pbuf *p, u16_t new_len) 00311 { 00312 struct pbuf *q; 00313 u16_t rem_len; /* remaining length */ 00314 s32_t grow; 00315 00316 LWIP_ASSERT("pbuf_realloc: p != NULL", p != NULL); 00317 LWIP_ASSERT("pbuf_realloc: sane p->type", p->type == PBUF_POOL || 00318 p->type == PBUF_ROM || 00319 p->type == PBUF_RAM || 00320 p->type == PBUF_REF); 00321 00322 /* desired length larger than current length? */ 00323 if (new_len >= p->tot_len) { 00324 /* enlarging not yet supported */ 00325 return; 00326 } 00327 00328 /* the pbuf chain grows by (new_len - p->tot_len) bytes 00329 * (which may be negative in case of shrinking) */ 00330 grow = new_len - p->tot_len; 00331 00332 /* first, step over any pbufs that should remain in the chain */ 00333 rem_len = new_len; 00334 q = p; 00335 /* should this pbuf be kept? */ 00336 while (rem_len > q->len) { 00337 /* decrease remaining length by pbuf length */ 00338 rem_len -= q->len; 00339 /* decrease total length indicator */ 00340 LWIP_ASSERT("grow < max_u16_t", grow < 0xffff); 00341 q->tot_len += (u16_t)grow; 00342 /* proceed to next pbuf in chain */ 00343 q = q->next; 00344 LWIP_ASSERT("pbuf_realloc: q != NULL", q != NULL); 00345 } 00346 /* we have now reached the new last pbuf (in q) */ 00347 /* rem_len == desired length for pbuf q */ 00348 00349 /* shrink allocated memory for PBUF_RAM */ 00350 /* (other types merely adjust their length fields */ 00351 if ((q->type == PBUF_RAM) && (rem_len != q->len)) { 00352 /* reallocate and adjust the length of the pbuf that will be split */ 00353 q = (struct pbuf *)mem_realloc(q, (u8_t *)q->payload - (u8_t *)q + rem_len); 00354 LWIP_ASSERT("mem_realloc give q == NULL", q != NULL); 00355 } 00356 /* adjust length fields for new last pbuf */ 00357 q->len = rem_len; 00358 q->tot_len = q->len; 00359 00360 /* any remaining pbufs in chain? */ 00361 if (q->next != NULL) { 00362 /* free remaining pbufs in chain */ 00363 pbuf_free(q->next); 00364 } 00365 /* q is last packet in chain */ 00366 q->next = NULL; 00367 00368 } 00369 00370 /** 00371 * Adjusts the payload pointer to hide or reveal headers in the payload. 00372 * 00373 * Adjusts the ->payload pointer so that space for a header 00374 * (dis)appears in the pbuf payload. 00375 * 00376 * The ->payload, ->tot_len and ->len fields are adjusted. 00377 * 00378 * @param p pbuf to change the header size. 00379 * @param header_size_increment Number of bytes to increment header size which 00380 * increases the size of the pbuf. New space is on the front. 00381 * (Using a negative value decreases the header size.) 00382 * If hdr_size_inc is 0, this function does nothing and returns succesful. 00383 * 00384 * PBUF_ROM and PBUF_REF type buffers cannot have their sizes increased, so 00385 * the call will fail. A check is made that the increase in header size does 00386 * not move the payload pointer in front of the start of the buffer. 00387 * @return non-zero on failure, zero on success. 00388 * 00389 */ 00390 u8_t 00391 pbuf_header(struct pbuf *p, s16_t header_size_increment) 00392 { 00393 u16_t type; 00394 void *payload; 00395 u16_t increment_magnitude; 00396 00397 LWIP_ASSERT("p != NULL", p != NULL); 00398 if ((header_size_increment == 0) || (p == NULL)) 00399 return 0; 00400 00401 if (header_size_increment < 0){ 00402 increment_magnitude = -header_size_increment; 00403 /* Check that we aren't going to move off the end of the pbuf */ 00404 LWIP_ERROR("increment_magnitude <= p->len", (increment_magnitude <= p->len), return 1;); 00405 } else { 00406 increment_magnitude = header_size_increment; 00407 #if 0 00408 /* Can't assert these as some callers speculatively call 00409 pbuf_header() to see if it's OK. Will return 1 below instead. */ 00410 /* Check that we've got the correct type of pbuf to work with */ 00411 LWIP_ASSERT("p->type == PBUF_RAM || p->type == PBUF_POOL", 00412 p->type == PBUF_RAM || p->type == PBUF_POOL); 00413 /* Check that we aren't going to move off the beginning of the pbuf */ 00414 LWIP_ASSERT("p->payload - increment_magnitude >= p + SIZEOF_STRUCT_PBUF", 00415 (u8_t *)p->payload - increment_magnitude >= (u8_t *)p + SIZEOF_STRUCT_PBUF); 00416 #endif 00417 } 00418 00419 type = p->type; 00420 /* remember current payload pointer */ 00421 payload = p->payload; 00422 00423 /* pbuf types containing payloads? */ 00424 if (type == PBUF_RAM || type == PBUF_POOL) { 00425 /* set new payload pointer */ 00426 p->payload = (u8_t *)p->payload - header_size_increment; 00427 /* boundary check fails? */ 00428 if ((u8_t *)p->payload < (u8_t *)p + SIZEOF_STRUCT_PBUF) { 00429 LWIP_DEBUGF( PBUF_DEBUG | 2, ("pbuf_header: failed as %p < %p (not enough space for new header size)\n", 00430 (void *)p->payload, 00431 (void *)(p + 1)));\ 00432 /* restore old payload pointer */ 00433 p->payload = payload; 00434 /* bail out unsuccesfully */ 00435 return 1; 00436 } 00437 /* pbuf types refering to external payloads? */ 00438 } else if (type == PBUF_REF || type == PBUF_ROM) { 00439 /* hide a header in the payload? */ 00440 if ((header_size_increment < 0) && (increment_magnitude <= p->len)) { 00441 /* increase payload pointer */ 00442 p->payload = (u8_t *)p->payload - header_size_increment; 00443 } else { 00444 /* cannot expand payload to front (yet!) 00445 * bail out unsuccesfully */ 00446 return 1; 00447 } 00448 } 00449 else { 00450 /* Unknown type */ 00451 LWIP_ASSERT("bad pbuf type", 0); 00452 return 1; 00453 } 00454 /* modify pbuf length fields */ 00455 p->len += header_size_increment; 00456 p->tot_len += header_size_increment; 00457 00458 LWIP_DEBUGF(PBUF_DEBUG, ("pbuf_header: old %p new %p (%"S16_F")\n", 00459 (void *)payload, (void *)p->payload, header_size_increment)); 00460 00461 return 0; 00462 } 00463 00464 /** 00465 * Dereference a pbuf chain or queue and deallocate any no-longer-used 00466 * pbufs at the head of this chain or queue. 00467 * 00468 * Decrements the pbuf reference count. If it reaches zero, the pbuf is 00469 * deallocated. 00470 * 00471 * For a pbuf chain, this is repeated for each pbuf in the chain, 00472 * up to the first pbuf which has a non-zero reference count after 00473 * decrementing. So, when all reference counts are one, the whole 00474 * chain is free'd. 00475 * 00476 * @param p The pbuf (chain) to be dereferenced. 00477 * 00478 * @return the number of pbufs that were de-allocated 00479 * from the head of the chain. 00480 * 00481 * @note MUST NOT be called on a packet queue (Not verified to work yet). 00482 * @note the reference counter of a pbuf equals the number of pointers 00483 * that refer to the pbuf (or into the pbuf). 00484 * 00485 * @internal examples: 00486 * 00487 * Assuming existing chains a->b->c with the following reference 00488 * counts, calling pbuf_free(a) results in: 00489 * 00490 * 1->2->3 becomes ...1->3 00491 * 3->3->3 becomes 2->3->3 00492 * 1->1->2 becomes ......1 00493 * 2->1->1 becomes 1->1->1 00494 * 1->1->1 becomes ....... 00495 * 00496 */ 00497 u8_t 00498 pbuf_free(struct pbuf *p) 00499 { 00500 u16_t type; 00501 struct pbuf *q; 00502 u8_t count; 00503 00504 if (p == NULL) { 00505 LWIP_ASSERT("p != NULL", p != NULL); 00506 /* if assertions are disabled, proceed with debug output */ 00507 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE | 2, ("pbuf_free(p == NULL) was called.\n")); 00508 return 0; 00509 } 00510 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE | 3, ("pbuf_free(%p)\n", (void *)p)); 00511 00512 PERF_START; 00513 00514 LWIP_ASSERT("pbuf_free: sane type", 00515 p->type == PBUF_RAM || p->type == PBUF_ROM || 00516 p->type == PBUF_REF || p->type == PBUF_POOL); 00517 00518 count = 0; 00519 /* de-allocate all consecutive pbufs from the head of the chain that 00520 * obtain a zero reference count after decrementing*/ 00521 while (p != NULL) { 00522 u16_t ref; 00523 SYS_ARCH_DECL_PROTECT(old_level); 00524 /* Since decrementing ref cannot be guaranteed to be a single machine operation 00525 * we must protect it. We put the new ref into a local variable to prevent 00526 * further protection. */ 00527 SYS_ARCH_PROTECT(old_level); 00528 /* all pbufs in a chain are referenced at least once */ 00529 LWIP_ASSERT("pbuf_free: p->ref > 0", p->ref > 0); 00530 /* decrease reference count (number of pointers to pbuf) */ 00531 ref = --(p->ref); 00532 SYS_ARCH_UNPROTECT(old_level); 00533 /* this pbuf is no longer referenced to? */ 00534 if (ref == 0) { 00535 /* remember next pbuf in chain for next iteration */ 00536 q = p->next; 00537 LWIP_DEBUGF( PBUF_DEBUG | 2, ("pbuf_free: deallocating %p\n", (void *)p)); 00538 type = p->type; 00539 /* is this a pbuf from the pool? */ 00540 if (type == PBUF_POOL) { 00541 memp_free(MEMP_PBUF_POOL, p); 00542 /* is this a ROM or RAM referencing pbuf? */ 00543 } else if (type == PBUF_ROM || type == PBUF_REF) { 00544 memp_free(MEMP_PBUF, p); 00545 /* type == PBUF_RAM */ 00546 } else { 00547 mem_free(p); 00548 } 00549 count++; 00550 /* proceed to next pbuf */ 00551 p = q; 00552 /* p->ref > 0, this pbuf is still referenced to */ 00553 /* (and so the remaining pbufs in chain as well) */ 00554 } else { 00555 LWIP_DEBUGF( PBUF_DEBUG | 2, ("pbuf_free: %p has ref %"U16_F", ending here.\n", (void *)p, ref)); 00556 /* stop walking through the chain */ 00557 p = NULL; 00558 } 00559 } 00560 PERF_STOP("pbuf_free"); 00561 /* return number of de-allocated pbufs */ 00562 return count; 00563 } 00564 00565 /** 00566 * Count number of pbufs in a chain 00567 * 00568 * @param p first pbuf of chain 00569 * @return the number of pbufs in a chain 00570 */ 00571 00572 u8_t 00573 pbuf_clen(struct pbuf *p) 00574 { 00575 u8_t len; 00576 00577 len = 0; 00578 while (p != NULL) { 00579 ++len; 00580 p = p->next; 00581 } 00582 return len; 00583 } 00584 00585 /** 00586 * Increment the reference count of the pbuf. 00587 * 00588 * @param p pbuf to increase reference counter of 00589 * 00590 */ 00591 void 00592 pbuf_ref(struct pbuf *p) 00593 { 00594 SYS_ARCH_DECL_PROTECT(old_level); 00595 /* pbuf given? */ 00596 if (p != NULL) { 00597 SYS_ARCH_PROTECT(old_level); 00598 ++(p->ref); 00599 SYS_ARCH_UNPROTECT(old_level); 00600 } 00601 } 00602 00603 /** 00604 * Concatenate two pbufs (each may be a pbuf chain) and take over 00605 * the caller's reference of the tail pbuf. 00606 * 00607 * @note The caller MAY NOT reference the tail pbuf afterwards. 00608 * Use pbuf_chain() for that purpose. 00609 * 00610 * @see pbuf_chain() 00611 */ 00612 00613 void 00614 pbuf_cat(struct pbuf *h, struct pbuf *t) 00615 { 00616 struct pbuf *p; 00617 00618 LWIP_ERROR("(h != NULL) && (t != NULL) (programmer violates API)", 00619 ((h != NULL) && (t != NULL)), return;); 00620 00621 /* proceed to last pbuf of chain */ 00622 for (p = h; p->next != NULL; p = p->next) { 00623 /* add total length of second chain to all totals of first chain */ 00624 p->tot_len += t->tot_len; 00625 } 00626 /* { p is last pbuf of first h chain, p->next == NULL } */ 00627 LWIP_ASSERT("p->tot_len == p->len (of last pbuf in chain)", p->tot_len == p->len); 00628 LWIP_ASSERT("p->next == NULL", p->next == NULL); 00629 /* add total length of second chain to last pbuf total of first chain */ 00630 p->tot_len += t->tot_len; 00631 /* chain last pbuf of head (p) with first of tail (t) */ 00632 p->next = t; 00633 /* p->next now references t, but the caller will drop its reference to t, 00634 * so netto there is no change to the reference count of t. 00635 */ 00636 } 00637 00638 /** 00639 * Chain two pbufs (or pbuf chains) together. 00640 * 00641 * The caller MUST call pbuf_free(t) once it has stopped 00642 * using it. Use pbuf_cat() instead if you no longer use t. 00643 * 00644 * @param h head pbuf (chain) 00645 * @param t tail pbuf (chain) 00646 * @note The pbufs MUST belong to the same packet. 00647 * @note MAY NOT be called on a packet queue. 00648 * 00649 * The ->tot_len fields of all pbufs of the head chain are adjusted. 00650 * The ->next field of the last pbuf of the head chain is adjusted. 00651 * The ->ref field of the first pbuf of the tail chain is adjusted. 00652 * 00653 */ 00654 void 00655 pbuf_chain(struct pbuf *h, struct pbuf *t) 00656 { 00657 pbuf_cat(h, t); 00658 /* t is now referenced by h */ 00659 pbuf_ref(t); 00660 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_FRESH | 2, ("pbuf_chain: %p references %p\n", (void *)h, (void *)t)); 00661 } 00662 00663 /** 00664 * Dechains the first pbuf from its succeeding pbufs in the chain. 00665 * 00666 * Makes p->tot_len field equal to p->len. 00667 * @param p pbuf to dechain 00668 * @return remainder of the pbuf chain, or NULL if it was de-allocated. 00669 * @note May not be called on a packet queue. 00670 */ 00671 struct pbuf * 00672 pbuf_dechain(struct pbuf *p) 00673 { 00674 struct pbuf *q; 00675 u8_t tail_gone = 1; 00676 /* tail */ 00677 q = p->next; 00678 /* pbuf has successor in chain? */ 00679 if (q != NULL) { 00680 /* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */ 00681 LWIP_ASSERT("p->tot_len == p->len + q->tot_len", q->tot_len == p->tot_len - p->len); 00682 /* enforce invariant if assertion is disabled */ 00683 q->tot_len = p->tot_len - p->len; 00684 /* decouple pbuf from remainder */ 00685 p->next = NULL; 00686 /* total length of pbuf p is its own length only */ 00687 p->tot_len = p->len; 00688 /* q is no longer referenced by p, free it */ 00689 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_STATE, ("pbuf_dechain: unreferencing %p\n", (void *)q)); 00690 tail_gone = pbuf_free(q); 00691 if (tail_gone > 0) { 00692 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_STATE, 00693 ("pbuf_dechain: deallocated %p (as it is no longer referenced)\n", (void *)q)); 00694 } 00695 /* return remaining tail or NULL if deallocated */ 00696 } 00697 /* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */ 00698 LWIP_ASSERT("p->tot_len == p->len", p->tot_len == p->len); 00699 return ((tail_gone > 0) ? NULL : q); 00700 } 00701 00702 /** 00703 * 00704 * Create PBUF_RAM copies of pbufs. 00705 * 00706 * Used to queue packets on behalf of the lwIP stack, such as 00707 * ARP based queueing. 00708 * 00709 * @note You MUST explicitly use p = pbuf_take(p); 00710 * 00711 * @note Only one packet is copied, no packet queue! 00712 * 00713 * @param p_to pbuf destination of the copy 00714 * @param p_from pbuf source of the copy 00715 * 00716 * @return ERR_OK if pbuf was copied 00717 * ERR_ARG if one of the pbufs is NULL or p_to is not big 00718 * enough to hold p_from 00719 */ 00720 err_t 00721 pbuf_copy(struct pbuf *p_to, struct pbuf *p_from) 00722 { 00723 u16_t offset_to=0, offset_from=0, len; 00724 00725 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE | 3, ("pbuf_copy(%p, %p)\n", 00726 (void*)p_to, (void*)p_from)); 00727 00728 /* is the target big enough to hold the source? */ 00729 LWIP_ERROR("pbuf_copy: target not big enough to hold source", ((p_to != NULL) && 00730 (p_from != NULL) && (p_to->tot_len >= p_from->tot_len)), return ERR_ARG;); 00731 00732 /* iterate through pbuf chain */ 00733 do 00734 { 00735 LWIP_ASSERT("p_to != NULL", p_to != NULL); 00736 /* copy one part of the original chain */ 00737 if ((p_to->len - offset_to) >= (p_from->len - offset_from)) { 00738 /* complete current p_from fits into current p_to */ 00739 len = p_from->len - offset_from; 00740 } else { 00741 /* current p_from does not fit into current p_to */ 00742 len = p_to->len - offset_to; 00743 } 00744 MEMCPY((u8_t*)p_to->payload + offset_to, (u8_t*)p_from->payload + offset_from, len); 00745 offset_to += len; 00746 offset_from += len; 00747 LWIP_ASSERT("offset_to <= p_to->len", offset_to <= p_to->len); 00748 if (offset_to == p_to->len) { 00749 /* on to next p_to (if any) */ 00750 offset_to = 0; 00751 p_to = p_to->next; 00752 } 00753 LWIP_ASSERT("offset_from <= p_from->len", offset_from <= p_from->len); 00754 if (offset_from >= p_from->len) { 00755 /* on to next p_from (if any) */ 00756 offset_from = 0; 00757 p_from = p_from->next; 00758 } 00759 00760 if((p_from != NULL) && (p_from->len == p_from->tot_len)) { 00761 /* don't copy more than one packet! */ 00762 LWIP_ERROR("pbuf_copy() does not allow packet queues!\n", 00763 (p_from->next == NULL), return ERR_VAL;); 00764 } 00765 if((p_to != NULL) && (p_to->len == p_to->tot_len)) { 00766 /* don't copy more than one packet! */ 00767 LWIP_ERROR("pbuf_copy() does not allow packet queues!\n", 00768 (p_to->next == NULL), return ERR_VAL;); 00769 } 00770 } while (p_from); 00771 LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE | 1, ("pbuf_copy: end of chain reached.\n")); 00772 return ERR_OK; 00773 } 00774 00775 /** 00776 * Copy (part of) the contents of a packet buffer 00777 * to an application supplied buffer. 00778 * 00779 * @param buf the pbuf from which to copy data 00780 * @param dataptr the application supplied buffer 00781 * @param len length of data to copy (dataptr must be big enough). No more 00782 * than buf->tot_len will be copied, irrespective of len 00783 * @param offset offset into the packet buffer from where to begin copying len bytes 00784 * @return the number of bytes copied, or 0 on failure 00785 */ 00786 u16_t 00787 pbuf_copy_partial(struct pbuf *buf, void *dataptr, u16_t len, u16_t offset) 00788 { 00789 struct pbuf *p; 00790 u16_t left; 00791 u16_t buf_copy_len; 00792 u16_t copied_total = 0; 00793 00794 LWIP_ERROR("pbuf_copy_partial: invalid buf", (buf != NULL), return 0;); 00795 LWIP_ERROR("pbuf_copy_partial: invalid dataptr", (dataptr != NULL), return 0;); 00796 00797 left = 0; 00798 00799 if((buf == NULL) || (dataptr == NULL)) { 00800 return 0; 00801 } 00802 00803 /* Note some systems use byte copy if dataptr or one of the pbuf payload pointers are unaligned. */ 00804 for(p = buf; len != 0 && p != NULL; p = p->next) { 00805 if ((offset != 0) && (offset >= p->len)) { 00806 /* don't copy from this buffer -> on to the next */ 00807 offset -= p->len; 00808 } else { 00809 /* copy from this buffer. maybe only partially. */ 00810 buf_copy_len = p->len - offset; 00811 if (buf_copy_len > len) 00812 buf_copy_len = len; 00813 /* copy the necessary parts of the buffer */ 00814 MEMCPY(&((char*)dataptr)[left], &((char*)p->payload)[offset], buf_copy_len); 00815 copied_total += buf_copy_len; 00816 left += buf_copy_len; 00817 len -= buf_copy_len; 00818 offset = 0; 00819 } 00820 } 00821 return copied_total; 00822 } 00823 00824 /** 00825 * Copy application supplied data into a pbuf. 00826 * This function can only be used to copy the equivalent of buf->tot_len data. 00827 * 00828 * @param buf pbuf to fill with data 00829 * @param dataptr application supplied data buffer 00830 * @param len length of the application supplied data buffer 00831 * 00832 * @return ERR_OK if successful, ERR_MEM if the pbuf is not big enough 00833 */ 00834 err_t 00835 pbuf_take(struct pbuf *buf, const void *dataptr, u16_t len) 00836 { 00837 struct pbuf *p; 00838 u16_t buf_copy_len; 00839 u16_t total_copy_len = len; 00840 u16_t copied_total = 0; 00841 00842 LWIP_ERROR("pbuf_take: invalid buf", (buf != NULL), return 0;); 00843 LWIP_ERROR("pbuf_take: invalid dataptr", (dataptr != NULL), return 0;); 00844 00845 if ((buf == NULL) || (dataptr == NULL) || (buf->tot_len < len)) { 00846 return ERR_ARG; 00847 } 00848 00849 /* Note some systems use byte copy if dataptr or one of the pbuf payload pointers are unaligned. */ 00850 for(p = buf; total_copy_len != 0; p = p->next) { 00851 LWIP_ASSERT("pbuf_take: invalid pbuf", p != NULL); 00852 buf_copy_len = total_copy_len; 00853 if (buf_copy_len > p->len) { 00854 /* this pbuf cannot hold all remaining data */ 00855 buf_copy_len = p->len; 00856 } 00857 /* copy the necessary parts of the buffer */ 00858 MEMCPY(p->payload, &((char*)dataptr)[copied_total], buf_copy_len); 00859 total_copy_len -= buf_copy_len; 00860 copied_total += buf_copy_len; 00861 } 00862 LWIP_ASSERT("did not copy all data", total_copy_len == 0 && copied_total == len); 00863 return ERR_OK; 00864 } 00865 00866 /** 00867 * Creates a single pbuf out of a queue of pbufs. 00868 * 00869 * @remark: The source pbuf 'p' is not freed by this function because that can 00870 * be illegal in some places! 00871 * 00872 * @param p the source pbuf 00873 * @param layer pbuf_layer of the new pbuf 00874 * 00875 * @return a new, single pbuf (p->next is NULL) 00876 * or the old pbuf if allocation fails 00877 */ 00878 struct pbuf* 00879 pbuf_coalesce(struct pbuf *p, pbuf_layer layer) 00880 { 00881 struct pbuf *q; 00882 err_t err; 00883 if (p->next == NULL) { 00884 return p; 00885 } 00886 q = pbuf_alloc(layer, p->tot_len, PBUF_RAM); 00887 if (q == NULL) { 00888 /* @todo: what do we do now? */ 00889 return p; 00890 } 00891 err = pbuf_copy(q, p); 00892 LWIP_ASSERT("pbuf_copy failed", err == ERR_OK); 00893 pbuf_free(p); 00894 return q; 00895 }
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