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lwip/core/pbuf.c
- Committer:
- segundo
- Date:
- 2010-11-09
- Revision:
- 0:ac1725ba162c
File content as of revision 0:ac1725ba162c:
/** * @file * Packet buffer management * * Packets are built from the pbuf data structure. It supports dynamic * memory allocation for packet contents or can reference externally * managed packet contents both in RAM and ROM. Quick allocation for * incoming packets is provided through pools with fixed sized pbufs. * * A packet may span over multiple pbufs, chained as a singly linked * list. This is called a "pbuf chain". * * Multiple packets may be queued, also using this singly linked list. * This is called a "packet queue". * * So, a packet queue consists of one or more pbuf chains, each of * which consist of one or more pbufs. CURRENTLY, PACKET QUEUES ARE * NOT SUPPORTED!!! Use helper structs to queue multiple packets. * * The differences between a pbuf chain and a packet queue are very * precise but subtle. * * The last pbuf of a packet has a ->tot_len field that equals the * ->len field. It can be found by traversing the list. If the last * pbuf of a packet has a ->next field other than NULL, more packets * are on the queue. * * Therefore, looping through a pbuf of a single packet, has an * loop end condition (tot_len == p->len), NOT (next == NULL). */ /* * Copyright (c) 2001-2004 Swedish Institute of Computer Science. * All rights reserved. * * Redistribution and use in source and binary forms, with or without modification, * are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY * OF SUCH DAMAGE. * * This file is part of the lwIP TCP/IP stack. * * Author: Adam Dunkels <adam@sics.se> * */ #include "lwip/opt.h" #include "lwip/stats.h" #include "lwip/def.h" #include "lwip/mem.h" #include "lwip/memp.h" #include "lwip/pbuf.h" #include "lwip/sys.h" #include "arch/perf.h" #if TCP_QUEUE_OOSEQ #include "lwip/tcp_impl.h" #endif #if LWIP_CHECKSUM_ON_COPY #include "lwip/inet_chksum.h" #endif #include <string.h> #define SIZEOF_STRUCT_PBUF LWIP_MEM_ALIGN_SIZE(sizeof(struct pbuf)) /* Since the pool is created in memp, PBUF_POOL_BUFSIZE will be automatically aligned there. Therefore, PBUF_POOL_BUFSIZE_ALIGNED can be used here. */ #define PBUF_POOL_BUFSIZE_ALIGNED LWIP_MEM_ALIGN_SIZE(PBUF_POOL_BUFSIZE) #if !LWIP_TCP || !TCP_QUEUE_OOSEQ || NO_SYS #define PBUF_POOL_IS_EMPTY() #else /* !LWIP_TCP || !TCP_QUEUE_OOSEQ || NO_SYS */ /** Define this to 0 to prevent freeing ooseq pbufs when the PBUF_POOL is empty */ #ifndef PBUF_POOL_FREE_OOSEQ #define PBUF_POOL_FREE_OOSEQ 1 #endif /* PBUF_POOL_FREE_OOSEQ */ #if PBUF_POOL_FREE_OOSEQ #include "lwip/tcpip.h" #define PBUF_POOL_IS_EMPTY() pbuf_pool_is_empty() static u8_t pbuf_free_ooseq_queued; /** * Attempt to reclaim some memory from queued out-of-sequence TCP segments * if we run out of pool pbufs. It's better to give priority to new packets * if we're running out. * * This must be done in the correct thread context therefore this function * can only be used with NO_SYS=0 and through tcpip_callback. */ static void pbuf_free_ooseq(void* arg) { struct tcp_pcb* pcb; SYS_ARCH_DECL_PROTECT(old_level); LWIP_UNUSED_ARG(arg); SYS_ARCH_PROTECT(old_level); pbuf_free_ooseq_queued = 0; SYS_ARCH_UNPROTECT(old_level); for (pcb = tcp_active_pcbs; NULL != pcb; pcb = pcb->next) { if (NULL != pcb->ooseq) { /** Free the ooseq pbufs of one PCB only */ LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_free_ooseq: freeing out-of-sequence pbufs\n")); tcp_segs_free(pcb->ooseq); pcb->ooseq = NULL; return; } } } /** Queue a call to pbuf_free_ooseq if not already queued. */ static void pbuf_pool_is_empty(void) { u8_t queued; SYS_ARCH_DECL_PROTECT(old_level); SYS_ARCH_PROTECT(old_level); queued = pbuf_free_ooseq_queued; pbuf_free_ooseq_queued = 1; SYS_ARCH_UNPROTECT(old_level); if(!queued) { /* queue a call to pbuf_free_ooseq if not already queued */ if(tcpip_callback_with_block(pbuf_free_ooseq, NULL, 0) != ERR_OK) { SYS_ARCH_PROTECT(old_level); pbuf_free_ooseq_queued = 0; SYS_ARCH_UNPROTECT(old_level); } } } #endif /* PBUF_POOL_FREE_OOSEQ */ #endif /* !LWIP_TCP || !TCP_QUEUE_OOSEQ || NO_SYS */ /** * Allocates a pbuf of the given type (possibly a chain for PBUF_POOL type). * * The actual memory allocated for the pbuf is determined by the * layer at which the pbuf is allocated and the requested size * (from the size parameter). * * @param layer flag to define header size * @param length size of the pbuf's payload * @param type this parameter decides how and where the pbuf * should be allocated as follows: * * - PBUF_RAM: buffer memory for pbuf is allocated as one large * chunk. This includes protocol headers as well. * - PBUF_ROM: no buffer memory is allocated for the pbuf, even for * protocol headers. Additional headers must be prepended * by allocating another pbuf and chain in to the front of * the ROM pbuf. It is assumed that the memory used is really * similar to ROM in that it is immutable and will not be * changed. Memory which is dynamic should generally not * be attached to PBUF_ROM pbufs. Use PBUF_REF instead. * - PBUF_REF: no buffer memory is allocated for the pbuf, even for * protocol headers. It is assumed that the pbuf is only * being used in a single thread. If the pbuf gets queued, * then pbuf_take should be called to copy the buffer. * - PBUF_POOL: the pbuf is allocated as a pbuf chain, with pbufs from * the pbuf pool that is allocated during pbuf_init(). * * @return the allocated pbuf. If multiple pbufs where allocated, this * is the first pbuf of a pbuf chain. */ struct pbuf * pbuf_alloc(pbuf_layer layer, u16_t length, pbuf_type type) { struct pbuf *p, *q, *r; u16_t offset; s32_t rem_len; /* remaining length */ LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloc(length=%"U16_F")\n", length)); /* determine header offset */ offset = 0; switch (layer) { case PBUF_TRANSPORT: /* add room for transport (often TCP) layer header */ offset += PBUF_TRANSPORT_HLEN; /* FALLTHROUGH */ case PBUF_IP: /* add room for IP layer header */ offset += PBUF_IP_HLEN; /* FALLTHROUGH */ case PBUF_LINK: /* add room for link layer header */ offset += PBUF_LINK_HLEN; break; case PBUF_RAW: break; default: LWIP_ASSERT("pbuf_alloc: bad pbuf layer", 0); return NULL; } switch (type) { case PBUF_POOL: /* allocate head of pbuf chain into p */ p = (struct pbuf *)memp_malloc(MEMP_PBUF_POOL); LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloc: allocated pbuf %p\n", (void *)p)); if (p == NULL) { PBUF_POOL_IS_EMPTY(); return NULL; } p->type = type; p->next = NULL; /* make the payload pointer point 'offset' bytes into pbuf data memory */ p->payload = LWIP_MEM_ALIGN((void *)((u8_t *)p + (SIZEOF_STRUCT_PBUF + offset))); LWIP_ASSERT("pbuf_alloc: pbuf p->payload properly aligned", ((mem_ptr_t)p->payload % MEM_ALIGNMENT) == 0); /* the total length of the pbuf chain is the requested size */ p->tot_len = length; /* set the length of the first pbuf in the chain */ p->len = LWIP_MIN(length, PBUF_POOL_BUFSIZE_ALIGNED - LWIP_MEM_ALIGN_SIZE(offset)); LWIP_ASSERT("check p->payload + p->len does not overflow pbuf", ((u8_t*)p->payload + p->len <= (u8_t*)p + SIZEOF_STRUCT_PBUF + PBUF_POOL_BUFSIZE_ALIGNED)); LWIP_ASSERT("PBUF_POOL_BUFSIZE must be bigger than MEM_ALIGNMENT", (PBUF_POOL_BUFSIZE_ALIGNED - LWIP_MEM_ALIGN_SIZE(offset)) > 0 ); /* set reference count (needed here in case we fail) */ p->ref = 1; /* now allocate the tail of the pbuf chain */ /* remember first pbuf for linkage in next iteration */ r = p; /* remaining length to be allocated */ rem_len = length - p->len; /* any remaining pbufs to be allocated? */ while (rem_len > 0) { q = (struct pbuf *)memp_malloc(MEMP_PBUF_POOL); if (q == NULL) { PBUF_POOL_IS_EMPTY(); /* free chain so far allocated */ pbuf_free(p); /* bail out unsuccesfully */ return NULL; } q->type = type; q->flags = 0; q->next = NULL; /* make previous pbuf point to this pbuf */ r->next = q; /* set total length of this pbuf and next in chain */ LWIP_ASSERT("rem_len < max_u16_t", rem_len < 0xffff); q->tot_len = (u16_t)rem_len; /* this pbuf length is pool size, unless smaller sized tail */ q->len = LWIP_MIN((u16_t)rem_len, PBUF_POOL_BUFSIZE_ALIGNED); q->payload = (void *)((u8_t *)q + SIZEOF_STRUCT_PBUF); LWIP_ASSERT("pbuf_alloc: pbuf q->payload properly aligned", ((mem_ptr_t)q->payload % MEM_ALIGNMENT) == 0); LWIP_ASSERT("check p->payload + p->len does not overflow pbuf", ((u8_t*)p->payload + p->len <= (u8_t*)p + SIZEOF_STRUCT_PBUF + PBUF_POOL_BUFSIZE_ALIGNED)); q->ref = 1; /* calculate remaining length to be allocated */ rem_len -= q->len; /* remember this pbuf for linkage in next iteration */ r = q; } /* end of chain */ /*r->next = NULL;*/ break; case PBUF_RAM: /* If pbuf is to be allocated in RAM, allocate memory for it. */ p = (struct pbuf*)mem_malloc(LWIP_MEM_ALIGN_SIZE(SIZEOF_STRUCT_PBUF + offset) + LWIP_MEM_ALIGN_SIZE(length)); if (p == NULL) { return NULL; } /* Set up internal structure of the pbuf. */ p->payload = LWIP_MEM_ALIGN((void *)((u8_t *)p + SIZEOF_STRUCT_PBUF + offset)); p->len = p->tot_len = length; p->next = NULL; p->type = type; LWIP_ASSERT("pbuf_alloc: pbuf->payload properly aligned", ((mem_ptr_t)p->payload % MEM_ALIGNMENT) == 0); break; /* pbuf references existing (non-volatile static constant) ROM payload? */ case PBUF_ROM: /* pbuf references existing (externally allocated) RAM payload? */ case PBUF_REF: /* only allocate memory for the pbuf structure */ p = (struct pbuf *)memp_malloc(MEMP_PBUF); if (p == NULL) { LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("pbuf_alloc: Could not allocate MEMP_PBUF for PBUF_%s.\n", (type == PBUF_ROM) ? "ROM" : "REF")); return NULL; } /* caller must set this field properly, afterwards */ p->payload = NULL; p->len = p->tot_len = length; p->next = NULL; p->type = type; break; default: LWIP_ASSERT("pbuf_alloc: erroneous type", 0); return NULL; } /* set reference count */ p->ref = 1; /* set flags */ p->flags = 0; LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloc(length=%"U16_F") == %p\n", length, (void *)p)); return p; } #if LWIP_SUPPORT_CUSTOM_PBUF /** Initialize a custom pbuf (already allocated). * * @param layer flag to define header size * @param length size of the pbuf's payload * @param type type of the pbuf (only used to treat the pbuf accordingly, as * this function allocates no memory) * @param p pointer to the custom pbuf to initialize (already allocated) * @param payload_mem pointer to the buffer that is used for payload and headers, * must be at least big enough to hold 'length' plus the header size, * may be NULL if set later * @param payload_mem_len the size of the 'payload_mem' buffer, must be at least * big enough to hold 'length' plus the header size */ 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) { u16_t offset; LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloced_custom(length=%"U16_F")\n", length)); /* determine header offset */ offset = 0; switch (l) { case PBUF_TRANSPORT: /* add room for transport (often TCP) layer header */ offset += PBUF_TRANSPORT_HLEN; /* FALLTHROUGH */ case PBUF_IP: /* add room for IP layer header */ offset += PBUF_IP_HLEN; /* FALLTHROUGH */ case PBUF_LINK: /* add room for link layer header */ offset += PBUF_LINK_HLEN; break; case PBUF_RAW: break; default: LWIP_ASSERT("pbuf_alloced_custom: bad pbuf layer", 0); return NULL; } if (LWIP_MEM_ALIGN_SIZE(offset) + length < payload_mem_len) { LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_LEVEL_WARNING, ("pbuf_alloced_custom(length=%"U16_F") buffer too short\n", length)); return NULL; } p->pbuf.next = NULL; if (payload_mem != NULL) { p->pbuf.payload = LWIP_MEM_ALIGN((void *)((u8_t *)payload_mem + offset)); } else { p->pbuf.payload = NULL; } p->pbuf.flags = PBUF_FLAG_IS_CUSTOM; p->pbuf.len = p->pbuf.tot_len = length; p->pbuf.type = type; p->pbuf.ref = 1; return &p->pbuf; } #endif /* LWIP_SUPPORT_CUSTOM_PBUF */ /** * Shrink a pbuf chain to a desired length. * * @param p pbuf to shrink. * @param new_len desired new length of pbuf chain * * Depending on the desired length, the first few pbufs in a chain might * be skipped and left unchanged. The new last pbuf in the chain will be * resized, and any remaining pbufs will be freed. * * @note If the pbuf is ROM/REF, only the ->tot_len and ->len fields are adjusted. * @note May not be called on a packet queue. * * @note Despite its name, pbuf_realloc cannot grow the size of a pbuf (chain). */ void pbuf_realloc(struct pbuf *p, u16_t new_len) { struct pbuf *q; u16_t rem_len; /* remaining length */ s32_t grow; LWIP_ASSERT("pbuf_realloc: p != NULL", p != NULL); LWIP_ASSERT("pbuf_realloc: sane p->type", p->type == PBUF_POOL || p->type == PBUF_ROM || p->type == PBUF_RAM || p->type == PBUF_REF); /* desired length larger than current length? */ if (new_len >= p->tot_len) { /* enlarging not yet supported */ return; } /* the pbuf chain grows by (new_len - p->tot_len) bytes * (which may be negative in case of shrinking) */ grow = new_len - p->tot_len; /* first, step over any pbufs that should remain in the chain */ rem_len = new_len; q = p; /* should this pbuf be kept? */ while (rem_len > q->len) { /* decrease remaining length by pbuf length */ rem_len -= q->len; /* decrease total length indicator */ LWIP_ASSERT("grow < max_u16_t", grow < 0xffff); q->tot_len += (u16_t)grow; /* proceed to next pbuf in chain */ q = q->next; LWIP_ASSERT("pbuf_realloc: q != NULL", q != NULL); } /* we have now reached the new last pbuf (in q) */ /* rem_len == desired length for pbuf q */ /* shrink allocated memory for PBUF_RAM */ /* (other types merely adjust their length fields */ if ((q->type == PBUF_RAM) && (rem_len != q->len)) { /* reallocate and adjust the length of the pbuf that will be split */ q = (struct pbuf *)mem_trim(q, (u16_t)((u8_t *)q->payload - (u8_t *)q) + rem_len); LWIP_ASSERT("mem_trim returned q == NULL", q != NULL); } /* adjust length fields for new last pbuf */ q->len = rem_len; q->tot_len = q->len; /* any remaining pbufs in chain? */ if (q->next != NULL) { /* free remaining pbufs in chain */ pbuf_free(q->next); } /* q is last packet in chain */ q->next = NULL; } /** * Adjusts the payload pointer to hide or reveal headers in the payload. * * Adjusts the ->payload pointer so that space for a header * (dis)appears in the pbuf payload. * * The ->payload, ->tot_len and ->len fields are adjusted. * * @param p pbuf to change the header size. * @param header_size_increment Number of bytes to increment header size which * increases the size of the pbuf. New space is on the front. * (Using a negative value decreases the header size.) * If hdr_size_inc is 0, this function does nothing and returns succesful. * * PBUF_ROM and PBUF_REF type buffers cannot have their sizes increased, so * the call will fail. A check is made that the increase in header size does * not move the payload pointer in front of the start of the buffer. * @return non-zero on failure, zero on success. * */ u8_t pbuf_header(struct pbuf *p, s16_t header_size_increment) { u16_t type; void *payload; u16_t increment_magnitude; LWIP_ASSERT("p != NULL", p != NULL); if ((header_size_increment == 0) || (p == NULL)) { return 0; } if (header_size_increment < 0){ increment_magnitude = -header_size_increment; /* Check that we aren't going to move off the end of the pbuf */ LWIP_ERROR("increment_magnitude <= p->len", (increment_magnitude <= p->len), return 1;); } else { increment_magnitude = header_size_increment; #if 0 /* Can't assert these as some callers speculatively call pbuf_header() to see if it's OK. Will return 1 below instead. */ /* Check that we've got the correct type of pbuf to work with */ LWIP_ASSERT("p->type == PBUF_RAM || p->type == PBUF_POOL", p->type == PBUF_RAM || p->type == PBUF_POOL); /* Check that we aren't going to move off the beginning of the pbuf */ LWIP_ASSERT("p->payload - increment_magnitude >= p + SIZEOF_STRUCT_PBUF", (u8_t *)p->payload - increment_magnitude >= (u8_t *)p + SIZEOF_STRUCT_PBUF); #endif } type = p->type; /* remember current payload pointer */ payload = p->payload; /* pbuf types containing payloads? */ if (type == PBUF_RAM || type == PBUF_POOL) { /* set new payload pointer */ p->payload = (u8_t *)p->payload - header_size_increment; /* boundary check fails? */ if ((u8_t *)p->payload < (u8_t *)p + SIZEOF_STRUCT_PBUF) { LWIP_DEBUGF( PBUF_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("pbuf_header: failed as %p < %p (not enough space for new header size)\n", (void *)p->payload, (void *)(p + 1))); /* restore old payload pointer */ p->payload = payload; /* bail out unsuccesfully */ return 1; } /* pbuf types refering to external payloads? */ } else if (type == PBUF_REF || type == PBUF_ROM) { /* hide a header in the payload? */ if ((header_size_increment < 0) && (increment_magnitude <= p->len)) { /* increase payload pointer */ p->payload = (u8_t *)p->payload - header_size_increment; } else { /* cannot expand payload to front (yet!) * bail out unsuccesfully */ return 1; } } else { /* Unknown type */ LWIP_ASSERT("bad pbuf type", 0); return 1; } /* modify pbuf length fields */ p->len += header_size_increment; p->tot_len += header_size_increment; LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_header: old %p new %p (%"S16_F")\n", (void *)payload, (void *)p->payload, header_size_increment)); return 0; } /** * Dereference a pbuf chain or queue and deallocate any no-longer-used * pbufs at the head of this chain or queue. * * Decrements the pbuf reference count. If it reaches zero, the pbuf is * deallocated. * * For a pbuf chain, this is repeated for each pbuf in the chain, * up to the first pbuf which has a non-zero reference count after * decrementing. So, when all reference counts are one, the whole * chain is free'd. * * @param p The pbuf (chain) to be dereferenced. * * @return the number of pbufs that were de-allocated * from the head of the chain. * * @note MUST NOT be called on a packet queue (Not verified to work yet). * @note the reference counter of a pbuf equals the number of pointers * that refer to the pbuf (or into the pbuf). * * @internal examples: * * Assuming existing chains a->b->c with the following reference * counts, calling pbuf_free(a) results in: * * 1->2->3 becomes ...1->3 * 3->3->3 becomes 2->3->3 * 1->1->2 becomes ......1 * 2->1->1 becomes 1->1->1 * 1->1->1 becomes ....... * */ u8_t pbuf_free(struct pbuf *p) { u16_t type; struct pbuf *q; u8_t count; if (p == NULL) { LWIP_ASSERT("p != NULL", p != NULL); /* if assertions are disabled, proceed with debug output */ LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("pbuf_free(p == NULL) was called.\n")); return 0; } LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_free(%p)\n", (void *)p)); PERF_START; LWIP_ASSERT("pbuf_free: sane type", p->type == PBUF_RAM || p->type == PBUF_ROM || p->type == PBUF_REF || p->type == PBUF_POOL); count = 0; /* de-allocate all consecutive pbufs from the head of the chain that * obtain a zero reference count after decrementing*/ while (p != NULL) { u16_t ref; SYS_ARCH_DECL_PROTECT(old_level); /* Since decrementing ref cannot be guaranteed to be a single machine operation * we must protect it. We put the new ref into a local variable to prevent * further protection. */ SYS_ARCH_PROTECT(old_level); /* all pbufs in a chain are referenced at least once */ LWIP_ASSERT("pbuf_free: p->ref > 0", p->ref > 0); /* decrease reference count (number of pointers to pbuf) */ ref = --(p->ref); SYS_ARCH_UNPROTECT(old_level); /* this pbuf is no longer referenced to? */ if (ref == 0) { /* remember next pbuf in chain for next iteration */ q = p->next; LWIP_DEBUGF( PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_free: deallocating %p\n", (void *)p)); type = p->type; #if LWIP_SUPPORT_CUSTOM_PBUF /* is this a custom pbuf? */ if ((p->flags & PBUF_FLAG_IS_CUSTOM) != 0) { struct pbuf_custom *pc = (struct pbuf_custom*)p; LWIP_ASSERT("pc->custom_free_function != NULL", pc->custom_free_function != NULL); pc->custom_free_function(p); } else #endif /* LWIP_SUPPORT_CUSTOM_PBUF */ { /* is this a pbuf from the pool? */ if (type == PBUF_POOL) { memp_free(MEMP_PBUF_POOL, p); /* is this a ROM or RAM referencing pbuf? */ } else if (type == PBUF_ROM || type == PBUF_REF) { memp_free(MEMP_PBUF, p); /* type == PBUF_RAM */ } else { mem_free(p); } } count++; /* proceed to next pbuf */ p = q; /* p->ref > 0, this pbuf is still referenced to */ /* (and so the remaining pbufs in chain as well) */ } else { LWIP_DEBUGF( PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_free: %p has ref %"U16_F", ending here.\n", (void *)p, ref)); /* stop walking through the chain */ p = NULL; } } PERF_STOP("pbuf_free"); /* return number of de-allocated pbufs */ return count; } /** * Count number of pbufs in a chain * * @param p first pbuf of chain * @return the number of pbufs in a chain */ u8_t pbuf_clen(struct pbuf *p) { u8_t len; len = 0; while (p != NULL) { ++len; p = p->next; } return len; } /** * Increment the reference count of the pbuf. * * @param p pbuf to increase reference counter of * */ void pbuf_ref(struct pbuf *p) { SYS_ARCH_DECL_PROTECT(old_level); /* pbuf given? */ if (p != NULL) { SYS_ARCH_PROTECT(old_level); ++(p->ref); SYS_ARCH_UNPROTECT(old_level); } } /** * Concatenate two pbufs (each may be a pbuf chain) and take over * the caller's reference of the tail pbuf. * * @note The caller MAY NOT reference the tail pbuf afterwards. * Use pbuf_chain() for that purpose. * * @see pbuf_chain() */ void pbuf_cat(struct pbuf *h, struct pbuf *t) { struct pbuf *p; LWIP_ERROR("(h != NULL) && (t != NULL) (programmer violates API)", ((h != NULL) && (t != NULL)), return;); /* proceed to last pbuf of chain */ for (p = h; p->next != NULL; p = p->next) { /* add total length of second chain to all totals of first chain */ p->tot_len += t->tot_len; } /* { p is last pbuf of first h chain, p->next == NULL } */ LWIP_ASSERT("p->tot_len == p->len (of last pbuf in chain)", p->tot_len == p->len); LWIP_ASSERT("p->next == NULL", p->next == NULL); /* add total length of second chain to last pbuf total of first chain */ p->tot_len += t->tot_len; /* chain last pbuf of head (p) with first of tail (t) */ p->next = t; /* p->next now references t, but the caller will drop its reference to t, * so netto there is no change to the reference count of t. */ } /** * Chain two pbufs (or pbuf chains) together. * * The caller MUST call pbuf_free(t) once it has stopped * using it. Use pbuf_cat() instead if you no longer use t. * * @param h head pbuf (chain) * @param t tail pbuf (chain) * @note The pbufs MUST belong to the same packet. * @note MAY NOT be called on a packet queue. * * The ->tot_len fields of all pbufs of the head chain are adjusted. * The ->next field of the last pbuf of the head chain is adjusted. * The ->ref field of the first pbuf of the tail chain is adjusted. * */ void pbuf_chain(struct pbuf *h, struct pbuf *t) { pbuf_cat(h, t); /* t is now referenced by h */ pbuf_ref(t); LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_chain: %p references %p\n", (void *)h, (void *)t)); } /** * Dechains the first pbuf from its succeeding pbufs in the chain. * * Makes p->tot_len field equal to p->len. * @param p pbuf to dechain * @return remainder of the pbuf chain, or NULL if it was de-allocated. * @note May not be called on a packet queue. */ struct pbuf * pbuf_dechain(struct pbuf *p) { struct pbuf *q; u8_t tail_gone = 1; /* tail */ q = p->next; /* pbuf has successor in chain? */ if (q != NULL) { /* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */ LWIP_ASSERT("p->tot_len == p->len + q->tot_len", q->tot_len == p->tot_len - p->len); /* enforce invariant if assertion is disabled */ q->tot_len = p->tot_len - p->len; /* decouple pbuf from remainder */ p->next = NULL; /* total length of pbuf p is its own length only */ p->tot_len = p->len; /* q is no longer referenced by p, free it */ LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_dechain: unreferencing %p\n", (void *)q)); tail_gone = pbuf_free(q); if (tail_gone > 0) { LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_dechain: deallocated %p (as it is no longer referenced)\n", (void *)q)); } /* return remaining tail or NULL if deallocated */ } /* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */ LWIP_ASSERT("p->tot_len == p->len", p->tot_len == p->len); return ((tail_gone > 0) ? NULL : q); } /** * * Create PBUF_RAM copies of pbufs. * * Used to queue packets on behalf of the lwIP stack, such as * ARP based queueing. * * @note You MUST explicitly use p = pbuf_take(p); * * @note Only one packet is copied, no packet queue! * * @param p_to pbuf destination of the copy * @param p_from pbuf source of the copy * * @return ERR_OK if pbuf was copied * ERR_ARG if one of the pbufs is NULL or p_to is not big * enough to hold p_from */ err_t pbuf_copy(struct pbuf *p_to, struct pbuf *p_from) { u16_t offset_to=0, offset_from=0, len; LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_copy(%p, %p)\n", (void*)p_to, (void*)p_from)); /* is the target big enough to hold the source? */ LWIP_ERROR("pbuf_copy: target not big enough to hold source", ((p_to != NULL) && (p_from != NULL) && (p_to->tot_len >= p_from->tot_len)), return ERR_ARG;); /* iterate through pbuf chain */ do { LWIP_ASSERT("p_to != NULL", p_to != NULL); /* copy one part of the original chain */ if ((p_to->len - offset_to) >= (p_from->len - offset_from)) { /* complete current p_from fits into current p_to */ len = p_from->len - offset_from; } else { /* current p_from does not fit into current p_to */ len = p_to->len - offset_to; } MEMCPY((u8_t*)p_to->payload + offset_to, (u8_t*)p_from->payload + offset_from, len); offset_to += len; offset_from += len; LWIP_ASSERT("offset_to <= p_to->len", offset_to <= p_to->len); if (offset_to == p_to->len) { /* on to next p_to (if any) */ offset_to = 0; p_to = p_to->next; } LWIP_ASSERT("offset_from <= p_from->len", offset_from <= p_from->len); if (offset_from >= p_from->len) { /* on to next p_from (if any) */ offset_from = 0; p_from = p_from->next; } if((p_from != NULL) && (p_from->len == p_from->tot_len)) { /* don't copy more than one packet! */ LWIP_ERROR("pbuf_copy() does not allow packet queues!\n", (p_from->next == NULL), return ERR_VAL;); } if((p_to != NULL) && (p_to->len == p_to->tot_len)) { /* don't copy more than one packet! */ LWIP_ERROR("pbuf_copy() does not allow packet queues!\n", (p_to->next == NULL), return ERR_VAL;); } } while (p_from); LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_copy: end of chain reached.\n")); return ERR_OK; } /** * Copy (part of) the contents of a packet buffer * to an application supplied buffer. * * @param buf the pbuf from which to copy data * @param dataptr the application supplied buffer * @param len length of data to copy (dataptr must be big enough). No more * than buf->tot_len will be copied, irrespective of len * @param offset offset into the packet buffer from where to begin copying len bytes * @return the number of bytes copied, or 0 on failure */ u16_t pbuf_copy_partial(struct pbuf *buf, void *dataptr, u16_t len, u16_t offset) { struct pbuf *p; u16_t left; u16_t buf_copy_len; u16_t copied_total = 0; LWIP_ERROR("pbuf_copy_partial: invalid buf", (buf != NULL), return 0;); LWIP_ERROR("pbuf_copy_partial: invalid dataptr", (dataptr != NULL), return 0;); left = 0; if((buf == NULL) || (dataptr == NULL)) { return 0; } /* Note some systems use byte copy if dataptr or one of the pbuf payload pointers are unaligned. */ for(p = buf; len != 0 && p != NULL; p = p->next) { if ((offset != 0) && (offset >= p->len)) { /* don't copy from this buffer -> on to the next */ offset -= p->len; } else { /* copy from this buffer. maybe only partially. */ buf_copy_len = p->len - offset; if (buf_copy_len > len) buf_copy_len = len; /* copy the necessary parts of the buffer */ MEMCPY(&((char*)dataptr)[left], &((char*)p->payload)[offset], buf_copy_len); copied_total += buf_copy_len; left += buf_copy_len; len -= buf_copy_len; offset = 0; } } return copied_total; } /** * Copy application supplied data into a pbuf. * This function can only be used to copy the equivalent of buf->tot_len data. * * @param buf pbuf to fill with data * @param dataptr application supplied data buffer * @param len length of the application supplied data buffer * * @return ERR_OK if successful, ERR_MEM if the pbuf is not big enough */ err_t pbuf_take(struct pbuf *buf, const void *dataptr, u16_t len) { struct pbuf *p; u16_t buf_copy_len; u16_t total_copy_len = len; u16_t copied_total = 0; LWIP_ERROR("pbuf_take: invalid buf", (buf != NULL), return 0;); LWIP_ERROR("pbuf_take: invalid dataptr", (dataptr != NULL), return 0;); if ((buf == NULL) || (dataptr == NULL) || (buf->tot_len < len)) { return ERR_ARG; } /* Note some systems use byte copy if dataptr or one of the pbuf payload pointers are unaligned. */ for(p = buf; total_copy_len != 0; p = p->next) { LWIP_ASSERT("pbuf_take: invalid pbuf", p != NULL); buf_copy_len = total_copy_len; if (buf_copy_len > p->len) { /* this pbuf cannot hold all remaining data */ buf_copy_len = p->len; } /* copy the necessary parts of the buffer */ MEMCPY(p->payload, &((char*)dataptr)[copied_total], buf_copy_len); total_copy_len -= buf_copy_len; copied_total += buf_copy_len; } LWIP_ASSERT("did not copy all data", total_copy_len == 0 && copied_total == len); return ERR_OK; } /** * Creates a single pbuf out of a queue of pbufs. * * @remark: Either the source pbuf 'p' is freed by this function or the original * pbuf 'p' is returned, therefore the caller has to check the result! * * @param p the source pbuf * @param layer pbuf_layer of the new pbuf * * @return a new, single pbuf (p->next is NULL) * or the old pbuf if allocation fails */ struct pbuf* pbuf_coalesce(struct pbuf *p, pbuf_layer layer) { struct pbuf *q; err_t err; if (p->next == NULL) { return p; } q = pbuf_alloc(layer, p->tot_len, PBUF_RAM); if (q == NULL) { /* @todo: what do we do now? */ return p; } err = pbuf_copy(q, p); LWIP_ASSERT("pbuf_copy failed", err == ERR_OK); pbuf_free(p); return q; } #if LWIP_CHECKSUM_ON_COPY /** * Copies data into a single pbuf (*not* into a pbuf queue!) and updates * the checksum while copying * * @param p the pbuf to copy data into * @param start_offset offset of p->payload where to copy the data to * @param dataptr data to copy into the pbuf * @param len length of data to copy into the pbuf * @param chksum pointer to the checksum which is updated * @return ERR_OK if successful, another error if the data does not fit * within the (first) pbuf (no pbuf queues!) */ err_t pbuf_fill_chksum(struct pbuf *p, u16_t start_offset, const void *dataptr, u16_t len, u16_t *chksum) { u32_t acc; u16_t copy_chksum; char *dst_ptr; LWIP_ASSERT("p != NULL", p != NULL); LWIP_ASSERT("dataptr != NULL", dataptr != NULL); LWIP_ASSERT("chksum != NULL", chksum != NULL); LWIP_ASSERT("len != 0", len != 0); if ((start_offset >= p->len) || (start_offset + len > p->len)) { return ERR_ARG; } dst_ptr = ((char*)p->payload) + start_offset; copy_chksum = LWIP_CHKSUM_COPY(dst_ptr, dataptr, len); if ((start_offset & 1) != 0) { copy_chksum = SWAP_BYTES_IN_WORD(copy_chksum); } acc = *chksum; acc += copy_chksum; *chksum = FOLD_U32T(acc); return ERR_OK; } #endif /* LWIP_CHECKSUM_ON_COPY */ /** Get one byte from the specified position in a pbuf * WARNING: returns zero for offset >= p->tot_len * * @param p pbuf to parse * @param offset offset into p of the byte to return * @return byte at an offset into p OR ZERO IF 'offset' >= p->tot_len */ u8_t pbuf_get_at(struct pbuf* p, u16_t offset) { u16_t copy_from = offset; struct pbuf* q = p; /* get the correct pbuf */ while ((q != NULL) && (q->len <= copy_from)) { copy_from -= q->len; q = q->next; } /* return requested data if pbuf is OK */ if ((q != NULL) && (q->len > copy_from)) { return ((u8_t*)q->payload)[copy_from]; } return 0; } /** Compare pbuf contents at specified offset with memory s2, both of length n * * @param p pbuf to compare * @param offset offset into p at wich to start comparing * @param s2 buffer to compare * @param n length of buffer to compare * @return zero if equal, nonzero otherwise * (0xffff if p is too short, diffoffset+1 otherwise) */ u16_t pbuf_memcmp(struct pbuf* p, u16_t offset, const void* s2, u16_t n) { u16_t start = offset; struct pbuf* q = p; /* get the correct pbuf */ while ((q != NULL) && (q->len <= start)) { start -= q->len; q = q->next; } /* return requested data if pbuf is OK */ if ((q != NULL) && (q->len > start)) { u16_t i; for(i = 0; i < n; i++) { u8_t a = pbuf_get_at(q, start + i); u8_t b = ((u8_t*)s2)[i]; if (a != b) { return i+1; } } return 0; } return 0xffff; } /** Find occurrence of mem (with length mem_len) in pbuf p, starting at offset * start_offset. * * @param p pbuf to search, maximum length is 0xFFFE since 0xFFFF is used as * return value 'not found' * @param mem search for the contents of this buffer * @param mem_len length of 'mem' * @param start_offset offset into p at which to start searching * @return 0xFFFF if substr was not found in p or the index where it was found */ u16_t pbuf_memfind(struct pbuf* p, const void* mem, u16_t mem_len, u16_t start_offset) { u16_t i; u16_t max = p->tot_len - mem_len; if (p->tot_len >= mem_len + start_offset) { for(i = start_offset; i <= max; ) { u16_t plus = pbuf_memcmp(p, i, mem, mem_len); if (plus == 0) { return i; } else { i += plus; } } } return 0xFFFF; } /** Find occurrence of substr with length substr_len in pbuf p, start at offset * start_offset * WARNING: in contrast to strstr(), this one does not stop at the first \0 in * the pbuf/source string! * * @param p pbuf to search, maximum length is 0xFFFE since 0xFFFF is used as * return value 'not found' * @param substr string to search for in p, maximum length is 0xFFFE * @return 0xFFFF if substr was not found in p or the index where it was found */ u16_t pbuf_strstr(struct pbuf* p, const char* substr) { size_t substr_len; if ((substr == NULL) || (substr[0] == 0) || (p->tot_len == 0xFFFF)) { return 0xFFFF; } substr_len = strlen(substr); if (substr_len >= 0xFFFF) { return 0xFFFF; } return pbuf_memfind(p, substr, (u16_t)substr_len, 0); }