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phunix/lib/liblwip/core/pbuf.c
Ambarisha B 7e55dbac33 LIBLWIP - updated to LwIP trunk 
commit a4a41b9023ef5b3a7c4a1cd82fb167fc63e706df
Author: goldsimon <goldsimon@gmx.de>
Date:   Wed Sep 26 21:50:42 2012 +0200

- This also brings in LwIP's IPv6 codebase

Signed-off-by: Tomas Hruby <tom@minix3.org>
2013-03-25 16:51:24 +01:00

1180 lines
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/**
* @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 LWIP_TCP && 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 || !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_callback_with_block(pbuf_free_ooseq_callback, NULL, 0) != 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_DECL_PROTECT(old_level);
SYS_ARCH_PROTECT(old_level);
pbuf_free_ooseq_pending = 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;
}
}
}
#if !NO_SYS
/**
* Just a callback function for tcpip_timeout() 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_DECL_PROTECT(old_level);
SYS_ARCH_PROTECT(old_level);
pbuf_free_ooseq_pending = 1;
SYS_ARCH_UNPROTECT(old_level);
#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 */
/**
* 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 */
switch (layer) {
case PBUF_TRANSPORT:
/* add room for transport (often TCP) layer header */
offset = PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN;
break;
case PBUF_IP:
/* add room for IP layer header */
offset = PBUF_LINK_HLEN + PBUF_IP_HLEN;
break;
case PBUF_LINK:
/* add room for link layer header */
offset = PBUF_LINK_HLEN;
break;
case PBUF_RAW:
offset = 0;
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.
* 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;
LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_alloced_custom(length=%"U16_F")\n", length));
/* determine header offset */
switch (l) {
case PBUF_TRANSPORT:
/* add room for transport (often TCP) layer header */
offset = PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN;
break;
case PBUF_IP:
/* add room for IP layer header */
offset = PBUF_LINK_HLEN + PBUF_IP_HLEN;
break;
case PBUF_LINK:
/* add room for link layer header */
offset = PBUF_LINK_HLEN;
break;
case PBUF_RAW:
offset = 0;
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 = (u8_t *)payload_mem + LWIP_MEM_ALIGN_SIZE(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
{
/* 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);
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 (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) || (p_from == NULL) , 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() 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);
}
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