| /** |
| * @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. |
| * The differences between a pbuf chain and a packet queue are very |
| * subtle. Currently, queues are only supported in a limited section |
| * of lwIP, this is the etharp queueing code. Outside of this section |
| * no packet queues are supported as of yet. |
| * |
| * 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) 2001-2003 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" |
| |
| static u8_t pbuf_pool_memory[(PBUF_POOL_SIZE * MEM_ALIGN_SIZE(PBUF_POOL_BUFSIZE + sizeof(struct pbuf)))]; |
| |
| #if !SYS_LIGHTWEIGHT_PROT |
| static volatile u8_t pbuf_pool_free_lock, pbuf_pool_alloc_lock; |
| static sys_sem_t pbuf_pool_free_sem; |
| #endif |
| |
| static struct pbuf *pbuf_pool = NULL; |
| |
| /** |
| * Initializes the pbuf module. |
| * |
| * A large part of memory is allocated for holding the pool of pbufs. |
| * The size of the individual pbufs in the pool is given by the size |
| * parameter, and the number of pbufs in the pool by the num parameter. |
| * |
| * After the memory has been allocated, the pbufs are set up. The |
| * ->next pointer in each pbuf is set up to point to the next pbuf in |
| * the pool. |
| * |
| */ |
| void |
| pbuf_init(void) |
| { |
| struct pbuf *p, *q = NULL; |
| u16_t i; |
| |
| pbuf_pool = (struct pbuf *)&pbuf_pool_memory[0]; |
| LWIP_ASSERT("pbuf_init: pool aligned", (long)pbuf_pool % MEM_ALIGNMENT == 0); |
| |
| #if PBUF_STATS |
| lwip_stats.pbuf.avail = PBUF_POOL_SIZE; |
| #endif /* PBUF_STATS */ |
| |
| /* Set up ->next pointers to link the pbufs of the pool together */ |
| p = pbuf_pool; |
| |
| for(i = 0; i < PBUF_POOL_SIZE; ++i) { |
| p->next = (struct pbuf *)((u8_t *)p + PBUF_POOL_BUFSIZE + sizeof(struct pbuf)); |
| p->len = p->tot_len = PBUF_POOL_BUFSIZE; |
| p->payload = MEM_ALIGN((void *)((u8_t *)p + sizeof(struct pbuf))); |
| p->flags = PBUF_FLAG_POOL; |
| q = p; |
| p = p->next; |
| } |
| |
| /* The ->next pointer of last pbuf is NULL to indicate that there |
| are no more pbufs in the pool */ |
| q->next = NULL; |
| |
| #if !SYS_LIGHTWEIGHT_PROT |
| pbuf_pool_alloc_lock = 0; |
| pbuf_pool_free_lock = 0; |
| pbuf_pool_free_sem = sys_sem_new(1); |
| #endif |
| } |
| |
| /** |
| * @internal only called from pbuf_alloc() |
| */ |
| static struct pbuf * |
| pbuf_pool_alloc(void) |
| { |
| struct pbuf *p = NULL; |
| |
| SYS_ARCH_DECL_PROTECT(old_level); |
| SYS_ARCH_PROTECT(old_level); |
| |
| #if !SYS_LIGHTWEIGHT_PROT |
| /* Next, check the actual pbuf pool, but if the pool is locked, we |
| pretend to be out of buffers and return NULL. */ |
| if (pbuf_pool_free_lock) { |
| #if PBUF_STATS |
| ++lwip_stats.pbuf.alloc_locked; |
| #endif /* PBUF_STATS */ |
| return NULL; |
| } |
| pbuf_pool_alloc_lock = 1; |
| if (!pbuf_pool_free_lock) { |
| #endif /* SYS_LIGHTWEIGHT_PROT */ |
| p = pbuf_pool; |
| if (p) { |
| pbuf_pool = p->next; |
| } |
| #if !SYS_LIGHTWEIGHT_PROT |
| #if PBUF_STATS |
| } else { |
| ++lwip_stats.pbuf.alloc_locked; |
| #endif /* PBUF_STATS */ |
| } |
| pbuf_pool_alloc_lock = 0; |
| #endif /* SYS_LIGHTWEIGHT_PROT */ |
| |
| #if PBUF_STATS |
| if (p != NULL) { |
| ++lwip_stats.pbuf.used; |
| if (lwip_stats.pbuf.used > lwip_stats.pbuf.max) { |
| lwip_stats.pbuf.max = lwip_stats.pbuf.used; |
| } |
| } |
| #endif /* PBUF_STATS */ |
| |
| SYS_ARCH_UNPROTECT(old_level); |
| return p; |
| } |
| |
| |
| /** |
| * Allocates a pbuf. |
| * |
| * 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 flag 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 l, u16_t length, pbuf_flag flag) |
| { |
| struct pbuf *p, *q, *r; |
| u16_t offset; |
| s32_t rem_len; /* remaining length */ |
| LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 3, ("pbuf_alloc(length=%u)\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_alloc: bad pbuf layer", 0); |
| return NULL; |
| } |
| |
| switch (flag) { |
| case PBUF_POOL: |
| /* allocate head of pbuf chain into p */ |
| p = pbuf_pool_alloc(); |
| LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 3, ("pbuf_alloc: allocated pbuf %p\n", (void *)p)); |
| if (p == NULL) { |
| #if PBUF_STATS |
| ++lwip_stats.pbuf.err; |
| #endif /* PBUF_STATS */ |
| return NULL; |
| } |
| p->next = NULL; |
| |
| /* make the payload pointer point 'offset' bytes into pbuf data memory */ |
| p->payload = MEM_ALIGN((void *)((u8_t *)p + (sizeof(struct pbuf) + offset))); |
| LWIP_ASSERT("pbuf_alloc: pbuf p->payload properly aligned", |
| ((u32_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 = length > PBUF_POOL_BUFSIZE - offset? PBUF_POOL_BUFSIZE - offset: length; |
| /* 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 = pbuf_pool_alloc(); |
| if (q == NULL) { |
| LWIP_DEBUGF(PBUF_DEBUG | 2, ("pbuf_alloc: Out of pbufs in pool.\n")); |
| #if PBUF_STATS |
| ++lwip_stats.pbuf.err; |
| #endif /* PBUF_STATS */ |
| /* free chain so far allocated */ |
| pbuf_free(p); |
| /* bail out unsuccesfully */ |
| return NULL; |
| } |
| q->next = NULL; |
| /* make previous pbuf point to this pbuf */ |
| r->next = q; |
| /* set total length of this pbuf and next in chain */ |
| q->tot_len = rem_len; |
| /* this pbuf length is pool size, unless smaller sized tail */ |
| q->len = rem_len > PBUF_POOL_BUFSIZE? PBUF_POOL_BUFSIZE: rem_len; |
| q->payload = (void *)((u8_t *)q + sizeof(struct pbuf)); |
| LWIP_ASSERT("pbuf_alloc: pbuf q->payload properly aligned", |
| ((u32_t)q->payload % MEM_ALIGNMENT) == 0); |
| 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 = mem_malloc(MEM_ALIGN_SIZE(sizeof(struct pbuf) + length + offset)); |
| if (p == NULL) { |
| return NULL; |
| } |
| /* Set up internal structure of the pbuf. */ |
| p->payload = MEM_ALIGN((void *)((u8_t *)p + sizeof(struct pbuf) + offset)); |
| p->len = p->tot_len = length; |
| p->next = NULL; |
| p->flags = PBUF_FLAG_RAM; |
| |
| LWIP_ASSERT("pbuf_alloc: pbuf->payload properly aligned", |
| ((u32_t)p->payload % MEM_ALIGNMENT) == 0); |
| break; |
| /* pbuf references existing (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 = memp_malloc(MEMP_PBUF); |
| if (p == NULL) { |
| LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 2, ("pbuf_alloc: Could not allocate MEMP_PBUF for PBUF_%s.\n", flag == 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->flags = (flag == PBUF_ROM? PBUF_FLAG_ROM: PBUF_FLAG_REF); |
| break; |
| default: |
| LWIP_ASSERT("pbuf_alloc: erroneous flag", 0); |
| return NULL; |
| } |
| /* set reference count */ |
| p->ref = 1; |
| LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 3, ("pbuf_alloc(length=%u) == %p\n", length, (void *)p)); |
| return p; |
| } |
| |
| |
| #if PBUF_STATS |
| #define DEC_PBUF_STATS do { --lwip_stats.pbuf.used; } while (0) |
| #else /* PBUF_STATS */ |
| #define DEC_PBUF_STATS |
| #endif /* PBUF_STATS */ |
| |
| #define PBUF_POOL_FAST_FREE(p) do { \ |
| p->next = pbuf_pool; \ |
| pbuf_pool = p; \ |
| DEC_PBUF_STATS; \ |
| } while (0) |
| |
| #if SYS_LIGHTWEIGHT_PROT |
| #define PBUF_POOL_FREE(p) do { \ |
| SYS_ARCH_DECL_PROTECT(old_level); \ |
| SYS_ARCH_PROTECT(old_level); \ |
| PBUF_POOL_FAST_FREE(p); \ |
| SYS_ARCH_UNPROTECT(old_level); \ |
| } while (0) |
| #else /* SYS_LIGHTWEIGHT_PROT */ |
| #define PBUF_POOL_FREE(p) do { \ |
| sys_sem_wait(pbuf_pool_free_sem); \ |
| PBUF_POOL_FAST_FREE(p); \ |
| sys_sem_signal(pbuf_pool_free_sem); \ |
| } while (0) |
| #endif /* SYS_LIGHTWEIGHT_PROT */ |
| |
| /** |
| * 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. |
| * |
| * @bug Cannot grow the size of a pbuf (chain) (yet). |
| */ |
| void |
| pbuf_realloc(struct pbuf *p, u16_t new_len) |
| { |
| struct pbuf *q; |
| u16_t rem_len; /* remaining length */ |
| s16_t grow; |
| |
| LWIP_ASSERT("pbuf_realloc: sane p->flags", p->flags == PBUF_FLAG_POOL || |
| p->flags == PBUF_FLAG_ROM || |
| p->flags == PBUF_FLAG_RAM || |
| p->flags == PBUF_FLAG_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 */ |
| q->tot_len += grow; |
| /* proceed to next pbuf in chain */ |
| q = q->next; |
| } |
| /* 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->flags == PBUF_FLAG_RAM) && (rem_len != q->len)) { |
| /* reallocate and adjust the length of the pbuf that will be split */ |
| mem_realloc(q, (u8_t *)q->payload - (u8_t *)q + rem_len); |
| } |
| /* 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 hdr_size 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.) |
| * |
| * 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 1 on failure, 0 on success. |
| * |
| * @note May not be called on a packet queue. |
| */ |
| u8_t |
| pbuf_header(struct pbuf *p, s16_t header_size) |
| { |
| void *payload; |
| |
| /* remember current payload pointer */ |
| payload = p->payload; |
| |
| /* pbuf types containing payloads? */ |
| if (p->flags == PBUF_FLAG_RAM || p->flags == PBUF_FLAG_POOL) { |
| /* set new payload pointer */ |
| p->payload = (u8_t *)p->payload - header_size; |
| /* boundary check fails? */ |
| if ((u8_t *)p->payload < (u8_t *)p + sizeof(struct pbuf)) { |
| LWIP_DEBUGF( PBUF_DEBUG | 2, ("pbuf_header: failed as %p < %p\n", |
| (u8_t *)p->payload, |
| (u8_t *)p + sizeof(struct pbuf)) );\ |
| /* restore old payload pointer */ |
| p->payload = payload; |
| /* bail out unsuccesfully */ |
| return 1; |
| } |
| /* pbuf types refering to payloads? */ |
| } else if (p->flags == PBUF_FLAG_REF || p->flags == PBUF_FLAG_ROM) { |
| /* hide a header in the payload? */ |
| if ((header_size < 0) && (header_size - p->len <= 0)) { |
| /* increase payload pointer */ |
| p->payload = (u8_t *)p->payload - header_size; |
| } else { |
| /* cannot expand payload to front (yet!) |
| * bail out unsuccesfully */ |
| return 1; |
| } |
| } |
| LWIP_DEBUGF( PBUF_DEBUG, ("pbuf_header: old %p new %p (%d)\n", (void *)payload, (void *)p->payload, header_size) ); |
| /* modify pbuf length fields */ |
| p->len += header_size; |
| p->tot_len += header_size; |
| |
| return 0; |
| } |
| |
| /** |
| * Dereference a pbuf (chain) and deallocate any no-longer-used |
| * pbufs at the head of this chain. |
| * |
| * 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 a pbuf which has a non-zero reference count after |
| * decrementing. (This might de-allocate the whole chain.) |
| * |
| * @param pbuf 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. |
| * @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) |
| { |
| struct pbuf *q; |
| u8_t count; |
| SYS_ARCH_DECL_PROTECT(old_level); |
| |
| if (p == NULL) { |
| LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 2, ("pbuf_free(p == NULL) was called.\n")); |
| return 0; |
| } |
| LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 3, ("pbuf_free(%p)\n", (void *)p)); |
| |
| PERF_START; |
| |
| LWIP_ASSERT("pbuf_free: sane flags", |
| p->flags == PBUF_FLAG_RAM || p->flags == PBUF_FLAG_ROM || |
| p->flags == PBUF_FLAG_REF || p->flags == PBUF_FLAG_POOL); |
| |
| count = 0; |
| /* Since decrementing ref cannot be guaranteed to be a single machine operation |
| * we must protect it. Also, the later test of ref must be protected. |
| */ |
| SYS_ARCH_PROTECT(old_level); |
| /* de-allocate all consecutive pbufs from the head of the chain that |
| * obtain a zero reference count after decrementing*/ |
| while (p != NULL) { |
| /* 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) */ |
| p->ref--; |
| /* this pbuf is no longer referenced to? */ |
| if (p->ref == 0) { |
| /* remember next pbuf in chain for next iteration */ |
| q = p->next; |
| LWIP_DEBUGF( PBUF_DEBUG | 2, ("pbuf_free: deallocating %p\n", (void *)p)); |
| /* is this a pbuf from the pool? */ |
| if (p->flags == PBUF_FLAG_POOL) { |
| p->len = p->tot_len = PBUF_POOL_BUFSIZE; |
| p->payload = (void *)((u8_t *)p + sizeof(struct pbuf)); |
| PBUF_POOL_FREE(p); |
| /* a ROM or RAM referencing pbuf */ |
| } else if (p->flags == PBUF_FLAG_ROM || p->flags == PBUF_FLAG_REF) { |
| memp_free(MEMP_PBUF, p); |
| /* p->flags == PBUF_FLAG_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 | 2, ("pbuf_free: %p has ref %u, ending here.\n", (void *)p, (unsigned int)p->ref)); |
| /* stop walking through chain */ |
| p = NULL; |
| } |
| } |
| SYS_ARCH_UNPROTECT(old_level); |
| 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_ASSERT("h != NULL", h != NULL); |
| LWIP_ASSERT("t != NULL", t != NULL); |
| if ((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); |
| /* 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; |
| } |
| |
| /** |
| * 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 | DBG_FRESH | 2, ("pbuf_chain: %p references %p\n", (void *)h, (void *)t)); |
| } |
| |
| /* For packet queueing. Note that queued packets must be dequeued first |
| * before calling any pbuf functions. */ |
| #if ARP_QUEUEING |
| /** |
| * Add a packet to the end of a queue. |
| * |
| * @param q pointer to first packet on the queue |
| * @param n packet to be queued |
| * |
| */ |
| void |
| pbuf_queue(struct pbuf *p, struct pbuf *n) |
| { |
| LWIP_ASSERT("p != NULL", p != NULL); |
| LWIP_ASSERT("n != NULL", n != NULL); |
| |
| if ((p == NULL) || (n == NULL)) |
| return; |
| |
| /* iterate through all packets on queue */ |
| while (p->next != NULL) { |
| /* be very picky about pbuf chain correctness */ |
| #if PBUF_DEBUG |
| /* iterate through all pbufs in packet */ |
| while (p->tot_len != p->len) { |
| /* make sure each packet is complete */ |
| LWIP_ASSERT("p->next != NULL", p->next != NULL); |
| p = p->next; |
| } |
| #endif |
| /* now p->tot_len == p->len */ |
| /* proceed to next packet on queue */ |
| p = p->next; |
| } |
| /* chain last pbuf of queue with n */ |
| p->next = n; |
| /* n is now referenced to one more time */ |
| pbuf_ref(n); |
| LWIP_DEBUGF(PBUF_DEBUG | DBG_FRESH | 2, ("pbuf_queue: referencing queued packet %p\n", (void *)n)); |
| } |
| |
| /** |
| * Remove a packet from the head of a queue. |
| * |
| * @param p pointer to first packet on the queue which will be dequeued. |
| * @return first packet on the remaining queue (NULL if no further packets). |
| * |
| */ |
| struct pbuf * |
| pbuf_dequeue(struct pbuf *p) |
| { |
| struct pbuf *q; |
| LWIP_ASSERT("p != NULL", p != NULL); |
| |
| /* iterate through all pbufs in packet */ |
| while (p->tot_len != p->len) { |
| /* make sure each packet is complete */ |
| LWIP_ASSERT("p->next != NULL", p->next != NULL); |
| p = p->next; |
| } |
| /* remember next packet on queue */ |
| q = p->next; |
| /* dequeue p from queue */ |
| p->next = NULL; |
| /* q is now referenced to one less time */ |
| pbuf_free(q); |
| LWIP_DEBUGF(PBUF_DEBUG | DBG_FRESH | 2, ("pbuf_dequeue: dereferencing remaining queue %p\n", (void *)q)); |
| return q; |
| } |
| #endif |
| |
| /** |
| * |
| * Create PBUF_POOL (or PBUF_RAM) copies of PBUF_REF pbufs. |
| * |
| * Used to queue packets on behalf of the lwIP stack, such as |
| * ARP based queueing. |
| * |
| * Go through a pbuf chain and replace any PBUF_REF buffers |
| * with PBUF_POOL (or PBUF_RAM) pbufs, each taking a copy of |
| * the referenced data. |
| * |
| * @note You MUST explicitly use p = pbuf_take(p); |
| * The pbuf you give as argument, may have been replaced |
| * by pbuf_take()! |
| * |
| * @note Any replaced pbufs will be freed through pbuf_free(). |
| * This may deallocate them if they become no longer referenced. |
| * |
| * @param p Head of pbuf chain to process |
| * |
| * @return Pointer to head of pbuf chain |
| */ |
| struct pbuf * |
| pbuf_take(struct pbuf *p) |
| { |
| struct pbuf *q , *prev, *head; |
| LWIP_ASSERT("pbuf_take: p != NULL\n", p != NULL); |
| LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 3, ("pbuf_take(%p)\n", (void*)p)); |
| |
| prev = NULL; |
| head = p; |
| /* iterate through pbuf chain */ |
| do |
| { |
| /* pbuf is of type PBUF_REF? */ |
| if (p->flags == PBUF_FLAG_REF) { |
| LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE, ("pbuf_take: encountered PBUF_REF %p\n", (void *)p)); |
| /* allocate a pbuf (w/ payload) fully in RAM */ |
| /* PBUF_POOL buffers are faster if we can use them */ |
| if (p->len <= PBUF_POOL_BUFSIZE) { |
| q = pbuf_alloc(PBUF_RAW, p->len, PBUF_POOL); |
| if (q == NULL) LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 2, ("pbuf_take: Could not allocate PBUF_POOL\n")); |
| } else { |
| /* no replacement pbuf yet */ |
| q = NULL; |
| LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 2, ("pbuf_take: PBUF_POOL too small to replace PBUF_REF\n")); |
| } |
| /* no (large enough) PBUF_POOL was available? retry with PBUF_RAM */ |
| if (q == NULL) { |
| q = pbuf_alloc(PBUF_RAW, p->len, PBUF_RAM); |
| if (q == NULL) LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 2, ("pbuf_take: Could not allocate PBUF_RAM\n")); |
| } |
| /* replacement pbuf could be allocated? */ |
| if (q != NULL) |
| { |
| /* copy p to q */ |
| /* copy successor */ |
| q->next = p->next; |
| /* remove linkage from original pbuf */ |
| p->next = NULL; |
| /* remove linkage to original pbuf */ |
| if (prev != NULL) { |
| /* prev->next == p at this point */ |
| LWIP_ASSERT("prev->next == p", prev->next == p); |
| /* break chain and insert new pbuf instead */ |
| prev->next = q; |
| /* prev == NULL, so we replaced the head pbuf of the chain */ |
| } else { |
| head = q; |
| } |
| /* copy pbuf payload */ |
| memcpy(q->payload, p->payload, p->len); |
| q->tot_len = p->tot_len; |
| q->len = p->len; |
| /* in case p was the first pbuf, it is no longer refered to by |
| * our caller, as the caller MUST do p = pbuf_take(p); |
| * in case p was not the first pbuf, it is no longer refered to |
| * by prev. we can safely free the pbuf here. |
| * (note that we have set p->next to NULL already so that |
| * we will not free the rest of the chain by accident.) |
| */ |
| pbuf_free(p); |
| /* do not copy ref, since someone else might be using the old buffer */ |
| LWIP_DEBUGF(PBUF_DEBUG, ("pbuf_take: replaced PBUF_REF %p with %p\n", (void *)p, (void *)q)); |
| p = q; |
| } else { |
| /* deallocate chain */ |
| pbuf_free(head); |
| LWIP_DEBUGF(PBUF_DEBUG | 2, ("pbuf_take: failed to allocate replacement pbuf for %p\n", (void *)p)); |
| return NULL; |
| } |
| /* p->flags != PBUF_FLAG_REF */ |
| } else { |
| LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 1, ("pbuf_take: skipping pbuf not of type PBUF_REF\n")); |
| } |
| /* remember this pbuf */ |
| prev = p; |
| /* proceed to next pbuf in original chain */ |
| p = p->next; |
| } while (p); |
| LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 1, ("pbuf_take: end of chain reached.\n")); |
| |
| return head; |
| } |
| |
| /** |
| * 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 | DBG_STATE, ("pbuf_dechain: unreferencing %p\n", (void *)q)); |
| tail_gone = pbuf_free(q); |
| if (tail_gone > 0) LWIP_DEBUGF(PBUF_DEBUG | DBG_STATE, |
| ("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); |
| } |