/** * @file * Packet buffer management */ /** * @defgroup pbuf Packet buffers (PBUF) * @ingroup infrastructure * * 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). * * Example of custom pbuf usage: @ref zerocopyrx */ /* * 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 * */ #include "lwip/opt.h" #include "lwip/pbuf.h" #include "lwip/stats.h" #include "lwip/def.h" #include "lwip/mem.h" #include "lwip/memp.h" #include "lwip/sys.h" #include "lwip/netif.h" #if LWIP_TCP && TCP_QUEUE_OOSEQ #include "lwip/priv/tcp_priv.h" #endif #if LWIP_CHECKSUM_ON_COPY #include "lwip/inet_chksum.h" #endif #include #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) static const struct pbuf * pbuf_skip_const(const struct pbuf *in, u16_t in_offset, u16_t *out_offset); #if !LWIP_TCP || !TCP_QUEUE_OOSEQ || !PBUF_POOL_FREE_OOSEQ #define PBUF_POOL_IS_EMPTY() #else /* !LWIP_TCP || !TCP_QUEUE_OOSEQ || !PBUF_POOL_FREE_OOSEQ */ #if !NO_SYS #ifndef PBUF_POOL_FREE_OOSEQ_QUEUE_CALL #include "lwip/tcpip.h" #define PBUF_POOL_FREE_OOSEQ_QUEUE_CALL() do { \ if (tcpip_try_callback(pbuf_free_ooseq_callback, NULL) != ERR_OK) { \ SYS_ARCH_PROTECT(old_level); \ pbuf_free_ooseq_pending = 0; \ SYS_ARCH_UNPROTECT(old_level); \ } } while(0) #endif /* PBUF_POOL_FREE_OOSEQ_QUEUE_CALL */ #endif /* !NO_SYS */ volatile u8_t pbuf_free_ooseq_pending; #define PBUF_POOL_IS_EMPTY() pbuf_pool_is_empty() /** * 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. */ #if !NO_SYS static #endif /* !NO_SYS */ void pbuf_free_ooseq(void) { struct tcp_pcb *pcb; SYS_ARCH_SET(pbuf_free_ooseq_pending, 0); for (pcb = tcp_active_pcbs; NULL != pcb; pcb = pcb->next) { if (pcb->ooseq != NULL) { /** 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_free_ooseq(pcb); return; } } } #if !NO_SYS /** * Just a callback function for tcpip_callback() that calls pbuf_free_ooseq(). */ static void pbuf_free_ooseq_callback(void *arg) { LWIP_UNUSED_ARG(arg); pbuf_free_ooseq(); } #endif /* !NO_SYS */ /** Queue a call to pbuf_free_ooseq if not already queued. */ static void pbuf_pool_is_empty(void) { #ifndef PBUF_POOL_FREE_OOSEQ_QUEUE_CALL SYS_ARCH_SET(pbuf_free_ooseq_pending, 1); #else /* PBUF_POOL_FREE_OOSEQ_QUEUE_CALL */ u8_t queued; SYS_ARCH_DECL_PROTECT(old_level); SYS_ARCH_PROTECT(old_level); queued = pbuf_free_ooseq_pending; pbuf_free_ooseq_pending = 1; SYS_ARCH_UNPROTECT(old_level); if (!queued) { /* queue a call to pbuf_free_ooseq if not already queued */ PBUF_POOL_FREE_OOSEQ_QUEUE_CALL(); } #endif /* PBUF_POOL_FREE_OOSEQ_QUEUE_CALL */ } #endif /* !LWIP_TCP || !TCP_QUEUE_OOSEQ || !PBUF_POOL_FREE_OOSEQ */ /* Initialize members of struct pbuf after allocation */ static void pbuf_init_alloced_pbuf(struct pbuf *p, void *payload, u16_t tot_len, u16_t len, pbuf_type type, u8_t flags) { p->next = NULL; p->payload = payload; p->tot_len = tot_len; p->len = len; p->type_internal = (u8_t)type; p->flags = flags; p->ref = 1; p->if_idx = NETIF_NO_INDEX; } /** * @ingroup pbuf * 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 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; u16_t offset = (u16_t)layer; LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloc(length=%"U16_F")\n", length)); switch (type) { case PBUF_REF: /* fall through */ case PBUF_ROM: p = pbuf_alloc_reference(NULL, length, type); break; case PBUF_POOL: { struct pbuf *q, *last; u16_t rem_len; /* remaining length */ p = NULL; last = NULL; rem_len = length; do { u16_t qlen; q = (struct pbuf *)memp_malloc(MEMP_PBUF_POOL); if (q == NULL) { PBUF_POOL_IS_EMPTY(); /* free chain so far allocated */ if (p) { pbuf_free(p); } /* bail out unsuccessfully */ return NULL; } qlen = LWIP_MIN(rem_len, (u16_t)(PBUF_POOL_BUFSIZE_ALIGNED - LWIP_MEM_ALIGN_SIZE(offset))); pbuf_init_alloced_pbuf(q, LWIP_MEM_ALIGN((void *)((u8_t *)q + SIZEOF_STRUCT_PBUF + offset)), rem_len, qlen, type, 0); LWIP_ASSERT("pbuf_alloc: pbuf q->payload properly aligned", ((mem_ptr_t)q->payload % MEM_ALIGNMENT) == 0); LWIP_ASSERT("PBUF_POOL_BUFSIZE must be bigger than MEM_ALIGNMENT", (PBUF_POOL_BUFSIZE_ALIGNED - LWIP_MEM_ALIGN_SIZE(offset)) > 0 ); if (p == NULL) { /* allocated head of pbuf chain (into p) */ p = q; } else { /* make previous pbuf point to this pbuf */ last->next = q; } last = q; rem_len = (u16_t)(rem_len - qlen); offset = 0; } while (rem_len > 0); break; } case PBUF_RAM: { mem_size_t payload_len = (mem_size_t)(LWIP_MEM_ALIGN_SIZE(offset) + LWIP_MEM_ALIGN_SIZE(length)); mem_size_t alloc_len = (mem_size_t)(LWIP_MEM_ALIGN_SIZE(SIZEOF_STRUCT_PBUF) + payload_len); /* bug #50040: Check for integer overflow when calculating alloc_len */ if ((payload_len < LWIP_MEM_ALIGN_SIZE(length)) || (alloc_len < LWIP_MEM_ALIGN_SIZE(length))) { return NULL; } /* If pbuf is to be allocated in RAM, allocate memory for it. */ p = (struct pbuf *)mem_malloc(alloc_len); if (p == NULL) { return NULL; } pbuf_init_alloced_pbuf(p, LWIP_MEM_ALIGN((void *)((u8_t *)p + SIZEOF_STRUCT_PBUF + offset)), length, length, type, 0); LWIP_ASSERT("pbuf_alloc: pbuf->payload properly aligned", ((mem_ptr_t)p->payload % MEM_ALIGNMENT) == 0); break; } default: LWIP_ASSERT("pbuf_alloc: erroneous type", 0); return NULL; } LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloc(length=%"U16_F") == %p\n", length, (void *)p)); return p; } /** * @ingroup pbuf * Allocates a pbuf for referenced data. * Referenced data can be volatile (PBUF_REF) or long-lived (PBUF_ROM). * * 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 payload referenced payload * @param length size of the pbuf's payload * @param type this parameter decides how and where the pbuf * should be allocated as follows: * * - PBUF_ROM: 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: 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. * * @return the allocated pbuf. */ struct pbuf * pbuf_alloc_reference(void *payload, u16_t length, pbuf_type type) { struct pbuf *p; LWIP_ASSERT("invalid pbuf_type", (type == PBUF_REF) || (type == PBUF_ROM)); /* 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_reference: Could not allocate MEMP_PBUF for PBUF_%s.\n", (type == PBUF_ROM) ? "ROM" : "REF")); return NULL; } pbuf_init_alloced_pbuf(p, payload, length, length, type, 0); return p; } #if LWIP_SUPPORT_CUSTOM_PBUF /** * @ingroup pbuf * Initialize a custom pbuf (already allocated). * Example of custom pbuf usage: @ref zerocopyrx * * @param l 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. * ATTENTION: The caller is responsible for correct alignment of this buffer!! * @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 = (u16_t)l; void *payload; LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloced_custom(length=%"U16_F")\n", length)); 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; } if (payload_mem != NULL) { payload = (u8_t *)payload_mem + LWIP_MEM_ALIGN_SIZE(offset); } else { payload = NULL; } pbuf_init_alloced_pbuf(&p->pbuf, payload, length, length, type, PBUF_FLAG_IS_CUSTOM); return &p->pbuf; } #endif /* LWIP_SUPPORT_CUSTOM_PBUF */ /** * @ingroup 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 */ u16_t shrink; LWIP_ASSERT("pbuf_realloc: p != NULL", p != NULL); /* 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) */ shrink = (u16_t)(p->tot_len - new_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 = (u16_t)(rem_len - q->len); /* decrease total length indicator */ q->tot_len = (u16_t)(q->tot_len - shrink); /* 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 (pbuf_match_allocsrc(q, PBUF_TYPE_ALLOC_SRC_MASK_STD_HEAP) && (rem_len != q->len) #if LWIP_SUPPORT_CUSTOM_PBUF && ((q->flags & PBUF_FLAG_IS_CUSTOM) == 0) #endif /* LWIP_SUPPORT_CUSTOM_PBUF */ ) { /* reallocate and adjust the length of the pbuf that will be split */ struct pbuf *r = (struct pbuf *)mem_trim(q, (mem_size_t)(((u8_t *)q->payload - (u8_t *)q) + rem_len)); LWIP_ASSERT("mem_trim returned r == NULL", r != NULL); /* help to detect faulty overridden implementation of mem_trim */ LWIP_ASSERT("mem_trim returned r != q", r == q); LWIP_UNUSED_ARG(r); } /* 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 reveal headers in the payload. * @see pbuf_add_header. * * @param p pbuf to change the header size. * @param header_size_increment Number of bytes to increment header size. * @param force Allow 'header_size_increment > 0' for PBUF_REF/PBUF_ROM types * * @return non-zero on failure, zero on success. * */ static u8_t pbuf_add_header_impl(struct pbuf *p, size_t header_size_increment, u8_t force) { u16_t type_internal; void *payload; u16_t increment_magnitude; LWIP_ASSERT("p != NULL", p != NULL); if ((p == NULL) || (header_size_increment > 0xFFFF)) { return 1; } if (header_size_increment == 0) { return 0; } increment_magnitude = (u16_t)header_size_increment; /* Do not allow tot_len to wrap as a result. */ if ((u16_t)(increment_magnitude + p->tot_len) < increment_magnitude) { return 1; } type_internal = p->type_internal; /* pbuf types containing payloads? */ if (type_internal & PBUF_TYPE_FLAG_STRUCT_DATA_CONTIGUOUS) { /* set new payload pointer */ payload = (u8_t *)p->payload - header_size_increment; /* boundary check fails? */ if ((u8_t *)payload < (u8_t *)p + SIZEOF_STRUCT_PBUF) { LWIP_DEBUGF( PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_add_header: failed as %p < %p (not enough space for new header size)\n", (void *)payload, (void *)((u8_t *)p + SIZEOF_STRUCT_PBUF))); /* bail out unsuccessfully */ return 1; } /* pbuf types referring to external payloads? */ } else { /* hide a header in the payload? */ if (force) { payload = (u8_t *)p->payload - header_size_increment; } else { /* cannot expand payload to front (yet!) * bail out unsuccessfully */ return 1; } } LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_add_header: old %p new %p (%"U16_F")\n", (void *)p->payload, (void *)payload, increment_magnitude)); /* modify pbuf fields */ p->payload = payload; p->len = (u16_t)(p->len + increment_magnitude); p->tot_len = (u16_t)(p->tot_len + increment_magnitude); return 0; } /** * Adjusts the payload pointer to reveal headers in the payload. * * Adjusts the ->payload pointer so that space for a header * 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. * If header_size_increment is 0, this function does nothing and returns successful. * * 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_add_header(struct pbuf *p, size_t header_size_increment) { return pbuf_add_header_impl(p, header_size_increment, 0); } /** * Same as @ref pbuf_add_header but does not check if 'header_size > 0' is allowed. * This is used internally only, to allow PBUF_REF for RX. */ u8_t pbuf_add_header_force(struct pbuf *p, size_t header_size_increment) { return pbuf_add_header_impl(p, header_size_increment, 1); } /** * Adjusts the payload pointer to hide headers in the payload. * * Adjusts the ->payload pointer so that space for a header * disappears in the pbuf payload. * * The ->payload, ->tot_len and ->len fields are adjusted. * * @param p pbuf to change the header size. * @param header_size_decrement Number of bytes to decrement header size which * decreases the size of the pbuf. * If header_size_decrement is 0, this function does nothing and returns successful. * @return non-zero on failure, zero on success. * */ u8_t pbuf_remove_header(struct pbuf *p, size_t header_size_decrement) { void *payload; u16_t increment_magnitude; LWIP_ASSERT("p != NULL", p != NULL); if ((p == NULL) || (header_size_decrement > 0xFFFF)) { return 1; } if (header_size_decrement == 0) { return 0; } increment_magnitude = (u16_t)header_size_decrement; /* 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;); /* remember current payload pointer */ payload = p->payload; LWIP_UNUSED_ARG(payload); /* only used in LWIP_DEBUGF below */ /* increase payload pointer (guarded by length check above) */ p->payload = (u8_t *)p->payload + header_size_decrement; /* modify pbuf length fields */ p->len = (u16_t)(p->len - increment_magnitude); p->tot_len = (u16_t)(p->tot_len - increment_magnitude); LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_remove_header: old %p new %p (%"U16_F")\n", (void *)payload, (void *)p->payload, increment_magnitude)); return 0; } static u8_t pbuf_header_impl(struct pbuf *p, s16_t header_size_increment, u8_t force) { if (header_size_increment < 0) { return pbuf_remove_header(p, (size_t) - header_size_increment); } else { return pbuf_add_header_impl(p, (size_t)header_size_increment, force); } } /** * 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 header_size_increment is 0, this function does nothing and returns successful. * * 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) { return pbuf_header_impl(p, header_size_increment, 0); } /** * Same as pbuf_header but does not check if 'header_size > 0' is allowed. * This is used internally only, to allow PBUF_REF for RX. */ u8_t pbuf_header_force(struct pbuf *p, s16_t header_size_increment) { return pbuf_header_impl(p, header_size_increment, 1); } /** Similar to pbuf_header(-size) but de-refs header pbufs for (size >= p->len) * * @param q pbufs to operate on * @param size The number of bytes to remove from the beginning of the pbuf list. * While size >= p->len, pbufs are freed. * ATTENTION: this is the opposite direction as @ref pbuf_header, but * takes an u16_t not s16_t! * @return the new head pbuf */ struct pbuf * pbuf_free_header(struct pbuf *q, u16_t size) { struct pbuf *p = q; u16_t free_left = size; while (free_left && p) { if (free_left >= p->len) { struct pbuf *f = p; free_left = (u16_t)(free_left - p->len); p = p->next; f->next = 0; pbuf_free(f); } else { pbuf_remove_header(p, free_left); free_left = 0; } } return p; } /** * @ingroup pbuf * 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 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) { u8_t alloc_src; 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; count = 0; /* de-allocate all consecutive pbufs from the head of the chain that * obtain a zero reference count after decrementing*/ while (p != NULL) { LWIP_PBUF_REF_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)); alloc_src = pbuf_get_allocsrc(p); #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 (alloc_src == PBUF_TYPE_ALLOC_SRC_MASK_STD_MEMP_PBUF_POOL) { memp_free(MEMP_PBUF_POOL, p); /* is this a ROM or RAM referencing pbuf? */ } else if (alloc_src == PBUF_TYPE_ALLOC_SRC_MASK_STD_MEMP_PBUF) { memp_free(MEMP_PBUF, p); /* type == PBUF_RAM */ } else if (alloc_src == PBUF_TYPE_ALLOC_SRC_MASK_STD_HEAP) { mem_free(p); } else { /* @todo: support freeing other types */ LWIP_ASSERT("invalid pbuf type", 0); } } 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, (u16_t)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 */ u16_t pbuf_clen(const struct pbuf *p) { u16_t len; len = 0; while (p != NULL) { ++len; p = p->next; } return len; } /** * @ingroup pbuf * Increment the reference count of the pbuf. * * @param p pbuf to increase reference counter of * */ void pbuf_ref(struct pbuf *p) { /* pbuf given? */ if (p != NULL) { SYS_ARCH_SET(p->ref, (LWIP_PBUF_REF_T)(p->ref + 1)); LWIP_ASSERT("pbuf ref overflow", p->ref > 0); } } /** * @ingroup pbuf * 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. * * This function explicitly does not check for tot_len overflow to prevent * failing to queue too long pbufs. This can produce invalid pbufs, so * handle with care! * * @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 = (u16_t)(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 = (u16_t)(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. */ } /** * @ingroup pbuf * 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 = (u16_t)(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); } /** * @ingroup pbuf * Copy the contents of one packet buffer into another. * * @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_VAL if any of the pbufs are part of a queue */ err_t pbuf_copy(struct pbuf *p_to, const struct pbuf *p_from) { LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_copy(%p, %p)\n", (const void *)p_to, (const void *)p_from)); LWIP_ERROR("pbuf_copy: invalid source", p_from != NULL, return ERR_ARG;); return pbuf_copy_partial_pbuf(p_to, p_from, p_from->tot_len, 0); } /** * @ingroup pbuf * Copy part or all of one packet buffer into another, to a specified offset. * * @note Only data in one packet is copied, no packet queue! * @note Argument order is shared with pbuf_copy, but different than pbuf_copy_partial. * * @param p_to pbuf destination of the copy * @param p_from pbuf source of the copy * @param copy_len number of bytes to copy * @param offset offset in destination pbuf where to copy to * * @return ERR_OK if copy_len bytes were copied * ERR_ARG if one of the pbufs is NULL or p_from is shorter than copy_len * or p_to is not big enough to hold copy_len at offset * ERR_VAL if any of the pbufs are part of a queue */ err_t pbuf_copy_partial_pbuf(struct pbuf *p_to, const struct pbuf *p_from, u16_t copy_len, u16_t offset) { size_t offset_to = offset, offset_from = 0, len; LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_copy_partial_pbuf(%p, %p, %"U16_F", %"U16_F")\n", (const void *)p_to, (const void *)p_from, copy_len, offset)); /* is the copy_len in range? */ LWIP_ERROR("pbuf_copy_partial_pbuf: copy_len bigger than source", ((p_from != NULL) && (p_from->tot_len >= copy_len)), return ERR_ARG;); /* is the target big enough to hold the source? */ LWIP_ERROR("pbuf_copy_partial_pbuf: target not big enough", ((p_to != NULL) && (p_to->tot_len >= (offset + copy_len))), return ERR_ARG;); /* iterate through pbuf chain */ do { /* 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; } len = LWIP_MIN(copy_len, len); MEMCPY((u8_t *)p_to->payload + offset_to, (u8_t *)p_from->payload + offset_from, len); offset_to += len; offset_from += len; copy_len -= len; LWIP_ASSERT("offset_to <= p_to->len", offset_to <= p_to->len); 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; LWIP_ERROR("p_from != NULL", (p_from != NULL) || (copy_len == 0), return ERR_ARG;); } if (offset_to == p_to->len) { /* on to next p_to (if any) */ offset_to = 0; p_to = p_to->next; LWIP_ERROR("p_to != NULL", (p_to != NULL) || (copy_len == 0), return ERR_ARG;); } if ((p_from != NULL) && (p_from->len == p_from->tot_len)) { /* don't copy more than one packet! */ LWIP_ERROR("pbuf_copy_partial_pbuf() does not allow packet queues!", (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_partial_pbuf() does not allow packet queues!", (p_to->next == NULL), return ERR_VAL;); } } while (copy_len); LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_copy_partial_pbuf: copy complete.\n")); return ERR_OK; } /** * @ingroup pbuf * 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(const struct pbuf *buf, void *dataptr, u16_t len, u16_t offset) { const struct pbuf *p; u16_t left = 0; 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;); /* 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 = (u16_t)(offset - p->len); } else { /* copy from this buffer. maybe only partially. */ buf_copy_len = (u16_t)(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 = (u16_t)(copied_total + buf_copy_len); left = (u16_t)(left + buf_copy_len); len = (u16_t)(len - buf_copy_len); offset = 0; } } return copied_total; } /** * @ingroup pbuf * Get part of a pbuf's payload as contiguous memory. The returned memory is * either a pointer into the pbuf's payload or, if split over multiple pbufs, * a copy into the user-supplied buffer. * * @param p the pbuf from which to copy data * @param buffer the application supplied buffer * @param bufsize size of 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 */ void * pbuf_get_contiguous(const struct pbuf *p, void *buffer, size_t bufsize, u16_t len, u16_t offset) { const struct pbuf *q; u16_t out_offset; LWIP_ERROR("pbuf_get_contiguous: invalid buf", (p != NULL), return NULL;); LWIP_ERROR("pbuf_get_contiguous: invalid dataptr", (buffer != NULL), return NULL;); LWIP_ERROR("pbuf_get_contiguous: invalid dataptr", (bufsize >= len), return NULL;); q = pbuf_skip_const(p, offset, &out_offset); if (q != NULL) { if (q->len >= (out_offset + len)) { /* all data in this pbuf, return zero-copy */ return (u8_t *)q->payload + out_offset; } /* need to copy */ if (pbuf_copy_partial(q, buffer, len, out_offset) != len) { /* copying failed: pbuf is too short */ return NULL; } return buffer; } /* pbuf is too short (offset does not fit in) */ return NULL; } #if LWIP_TCP && TCP_QUEUE_OOSEQ && LWIP_WND_SCALE /** * This method modifies a 'pbuf chain', so that its total length is * smaller than 64K. The remainder of the original pbuf chain is stored * in *rest. * This function never creates new pbufs, but splits an existing chain * in two parts. The tot_len of the modified packet queue will likely be * smaller than 64K. * 'packet queues' are not supported by this function. * * @param p the pbuf queue to be split * @param rest pointer to store the remainder (after the first 64K) */ void pbuf_split_64k(struct pbuf *p, struct pbuf **rest) { *rest = NULL; if ((p != NULL) && (p->next != NULL)) { u16_t tot_len_front = p->len; struct pbuf *i = p; struct pbuf *r = p->next; /* continue until the total length (summed up as u16_t) overflows */ while ((r != NULL) && ((u16_t)(tot_len_front + r->len) >= tot_len_front)) { tot_len_front = (u16_t)(tot_len_front + r->len); i = r; r = r->next; } /* i now points to last packet of the first segment. Set next pointer to NULL */ i->next = NULL; if (r != NULL) { /* Update the tot_len field in the first part */ for (i = p; i != NULL; i = i->next) { i->tot_len = (u16_t)(i->tot_len - r->tot_len); LWIP_ASSERT("tot_len/len mismatch in last pbuf", (i->next != NULL) || (i->tot_len == i->len)); } if (p->flags & PBUF_FLAG_TCP_FIN) { r->flags |= PBUF_FLAG_TCP_FIN; } /* tot_len field in rest does not need modifications */ /* reference counters do not need modifications */ *rest = r; } } } #endif /* LWIP_TCP && TCP_QUEUE_OOSEQ && LWIP_WND_SCALE */ /* Actual implementation of pbuf_skip() but returning const pointer... */ static const struct pbuf * pbuf_skip_const(const struct pbuf *in, u16_t in_offset, u16_t *out_offset) { u16_t offset_left = in_offset; const struct pbuf *q = in; /* get the correct pbuf */ while ((q != NULL) && (q->len <= offset_left)) { offset_left = (u16_t)(offset_left - q->len); q = q->next; } if (out_offset != NULL) { *out_offset = offset_left; } return q; } /** * @ingroup pbuf * Skip a number of bytes at the start of a pbuf * * @param in input pbuf * @param in_offset offset to skip * @param out_offset resulting offset in the returned pbuf * @return the pbuf in the queue where the offset is */ struct pbuf * pbuf_skip(struct pbuf *in, u16_t in_offset, u16_t *out_offset) { const struct pbuf *out = pbuf_skip_const(in, in_offset, out_offset); return LWIP_CONST_CAST(struct pbuf *, out); } /** * @ingroup pbuf * 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; size_t buf_copy_len; size_t total_copy_len = len; size_t copied_total = 0; LWIP_ERROR("pbuf_take: invalid buf", (buf != NULL), return ERR_ARG;); LWIP_ERROR("pbuf_take: invalid dataptr", (dataptr != NULL), return ERR_ARG;); LWIP_ERROR("pbuf_take: buf not large enough", (buf->tot_len >= len), return ERR_MEM;); 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, &((const 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; } /** * @ingroup pbuf * Same as pbuf_take() but puts data at an offset * * @param buf pbuf to fill with data * @param dataptr application supplied data buffer * @param len length of the application supplied data buffer * @param offset offset in pbuf where to copy dataptr to * * @return ERR_OK if successful, ERR_MEM if the pbuf is not big enough */ err_t pbuf_take_at(struct pbuf *buf, const void *dataptr, u16_t len, u16_t offset) { u16_t target_offset; struct pbuf *q = pbuf_skip(buf, offset, &target_offset); /* return requested data if pbuf is OK */ if ((q != NULL) && (q->tot_len >= target_offset + len)) { u16_t remaining_len = len; const u8_t *src_ptr = (const u8_t *)dataptr; /* copy the part that goes into the first pbuf */ u16_t first_copy_len; LWIP_ASSERT("check pbuf_skip result", target_offset < q->len); first_copy_len = (u16_t)LWIP_MIN(q->len - target_offset, len); MEMCPY(((u8_t *)q->payload) + target_offset, dataptr, first_copy_len); remaining_len = (u16_t)(remaining_len - first_copy_len); src_ptr += first_copy_len; if (remaining_len > 0) { return pbuf_take(q->next, src_ptr, remaining_len); } return ERR_OK; } return ERR_MEM; } /** * @ingroup pbuf * 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; if (p->next == NULL) { return p; } q = pbuf_clone(layer, PBUF_RAM, p); if (q == NULL) { /* @todo: what do we do now? */ return p; } pbuf_free(p); return q; } /** * @ingroup pbuf * Allocates a new pbuf of same length (via pbuf_alloc()) and copies the source * pbuf into this new pbuf (using pbuf_copy()). * * @param layer pbuf_layer of the new pbuf * @param type this parameter decides how and where the pbuf should be allocated * (@see pbuf_alloc()) * @param p the source pbuf * * @return a new pbuf or NULL if allocation fails */ struct pbuf * pbuf_clone(pbuf_layer layer, pbuf_type type, struct pbuf *p) { struct pbuf *q; err_t err; q = pbuf_alloc(layer, p->tot_len, type); if (q == NULL) { return NULL; } err = pbuf_copy(q, p); LWIP_UNUSED_ARG(err); /* in case of LWIP_NOASSERT */ LWIP_ASSERT("pbuf_copy failed", err == ERR_OK); 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 */ /** * @ingroup pbuf * 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(const struct pbuf *p, u16_t offset) { int ret = pbuf_try_get_at(p, offset); if (ret >= 0) { return (u8_t)ret; } return 0; } /** * @ingroup pbuf * Get one byte from the specified position in a pbuf * * @param p pbuf to parse * @param offset offset into p of the byte to return * @return byte at an offset into p [0..0xFF] OR negative if 'offset' >= p->tot_len */ int pbuf_try_get_at(const struct pbuf *p, u16_t offset) { u16_t q_idx; const struct pbuf *q = pbuf_skip_const(p, offset, &q_idx); /* return requested data if pbuf is OK */ if ((q != NULL) && (q->len > q_idx)) { return ((u8_t *)q->payload)[q_idx]; } return -1; } /** * @ingroup pbuf * Put one byte to the specified position in a pbuf * WARNING: silently ignores offset >= p->tot_len * * @param p pbuf to fill * @param offset offset into p of the byte to write * @param data byte to write at an offset into p */ void pbuf_put_at(struct pbuf *p, u16_t offset, u8_t data) { u16_t q_idx; struct pbuf *q = pbuf_skip(p, offset, &q_idx); /* write requested data if pbuf is OK */ if ((q != NULL) && (q->len > q_idx)) { ((u8_t *)q->payload)[q_idx] = data; } } /** * @ingroup pbuf * Compare pbuf contents at specified offset with memory s2, both of length n * * @param p pbuf to compare * @param offset offset into p at which 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(const struct pbuf *p, u16_t offset, const void *s2, u16_t n) { u16_t start = offset; const struct pbuf *q = p; u16_t i; /* pbuf long enough to perform check? */ if (p->tot_len < (offset + n)) { return 0xffff; } /* get the correct pbuf from chain. We know it succeeds because of p->tot_len check above. */ while ((q != NULL) && (q->len <= start)) { start = (u16_t)(start - q->len); q = q->next; } /* return requested data if pbuf is OK */ for (i = 0; i < n; i++) { /* We know pbuf_get_at() succeeds because of p->tot_len check above. */ u8_t a = pbuf_get_at(q, (u16_t)(start + i)); u8_t b = ((const u8_t *)s2)[i]; if (a != b) { return (u16_t)LWIP_MIN(i + 1, 0xFFFF); } } return 0; } /** * @ingroup pbuf * 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(const struct pbuf *p, const void *mem, u16_t mem_len, u16_t start_offset) { u16_t i; u16_t max_cmp_start = (u16_t)(p->tot_len - mem_len); if (p->tot_len >= mem_len + start_offset) { for (i = start_offset; i <= max_cmp_start; i++) { u16_t plus = pbuf_memcmp(p, i, mem, mem_len); if (plus == 0) { return i; } } } 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(const 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); }