www.pudn.com > lwip-1.3.0.rar > netbuf.c
/**
* @file
* Network buffer management
*
*/
/*
* 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"
#if LWIP_NETCONN /* don't build if not configured for use in lwipopts.h */
#include "lwip/netbuf.h"
#include "lwip/memp.h"
#include
/**
* Create (allocate) and initialize a new netbuf.
* The netbuf doesn't yet contain a packet buffer!
*
* @return a pointer to a new netbuf
* NULL on lack of memory
*/
struct
netbuf *netbuf_new(void)
{
struct netbuf *buf;
buf = memp_malloc(MEMP_NETBUF);
if (buf != NULL) {
buf->p = NULL;
buf->ptr = NULL;
buf->addr = NULL;
return buf;
} else {
return NULL;
}
}
/**
* Deallocate a netbuf allocated by netbuf_new().
*
* @param buf pointer to a netbuf allocated by netbuf_new()
*/
void
netbuf_delete(struct netbuf *buf)
{
if (buf != NULL) {
if (buf->p != NULL) {
pbuf_free(buf->p);
buf->p = buf->ptr = NULL;
}
memp_free(MEMP_NETBUF, buf);
}
}
/**
* Allocate memory for a packet buffer for a given netbuf.
*
* @param buf the netbuf for which to allocate a packet buffer
* @param size the size of the packet buffer to allocate
* @return pointer to the allocated memory
* NULL if no memory could be allocated
*/
void *
netbuf_alloc(struct netbuf *buf, u16_t size)
{
LWIP_ERROR("netbuf_alloc: invalid buf", (buf != NULL), return NULL;);
/* Deallocate any previously allocated memory. */
if (buf->p != NULL) {
pbuf_free(buf->p);
}
buf->p = pbuf_alloc(PBUF_TRANSPORT, size, PBUF_RAM);
if (buf->p == NULL) {
return NULL;
}
LWIP_ASSERT("check that first pbuf can hold size",
(buf->p->len >= size));
buf->ptr = buf->p;
return buf->p->payload;
}
/**
* Free the packet buffer included in a netbuf
*
* @param buf pointer to the netbuf which contains the packet buffer to free
*/
void
netbuf_free(struct netbuf *buf)
{
LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return;);
if (buf->p != NULL) {
pbuf_free(buf->p);
}
buf->p = buf->ptr = NULL;
}
/**
* Let a netbuf reference existing (non-volatile) data.
*
* @param buf netbuf which should reference the data
* @param dataptr pointer to the data to reference
* @param size size of the data
* @return ERR_OK if data is referenced
* ERR_MEM if data couldn't be referenced due to lack of memory
*/
err_t
netbuf_ref(struct netbuf *buf, const void *dataptr, u16_t size)
{
LWIP_ERROR("netbuf_ref: invalid buf", (buf != NULL), return ERR_ARG;);
if (buf->p != NULL) {
pbuf_free(buf->p);
}
buf->p = pbuf_alloc(PBUF_TRANSPORT, 0, PBUF_REF);
if (buf->p == NULL) {
buf->ptr = NULL;
return ERR_MEM;
}
buf->p->payload = (void*)dataptr;
buf->p->len = buf->p->tot_len = size;
buf->ptr = buf->p;
return ERR_OK;
}
/**
* Chain one netbuf to another (@see pbuf_chain)
*
* @param head the first netbuf
* @param tail netbuf to chain after head
*/
void
netbuf_chain(struct netbuf *head, struct netbuf *tail)
{
LWIP_ERROR("netbuf_ref: invalid head", (head != NULL), return;);
LWIP_ERROR("netbuf_chain: invalid tail", (tail != NULL), return;);
pbuf_chain(head->p, tail->p);
head->ptr = head->p;
memp_free(MEMP_NETBUF, tail);
}
/**
* Get the data pointer and length of the data inside a netbuf.
*
* @param buf netbuf to get the data from
* @param dataptr pointer to a void pointer where to store the data pointer
* @param len pointer to an u16_t where the length of the data is stored
* @return ERR_OK if the information was retreived,
* ERR_BUF on error.
*/
err_t
netbuf_data(struct netbuf *buf, void **dataptr, u16_t *len)
{
LWIP_ERROR("netbuf_data: invalid buf", (buf != NULL), return ERR_ARG;);
LWIP_ERROR("netbuf_data: invalid dataptr", (dataptr != NULL), return ERR_ARG;);
LWIP_ERROR("netbuf_data: invalid len", (len != NULL), return ERR_ARG;);
if (buf->ptr == NULL) {
return ERR_BUF;
}
*dataptr = buf->ptr->payload;
*len = buf->ptr->len;
return ERR_OK;
}
/**
* Move the current data pointer of a packet buffer contained in a netbuf
* to the next part.
* The packet buffer itself is not modified.
*
* @param buf the netbuf to modify
* @return -1 if there is no next part
* 1 if moved to the next part but now there is no next part
* 0 if moved to the next part and there are still more parts
*/
s8_t
netbuf_next(struct netbuf *buf)
{
LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return -1;);
if (buf->ptr->next == NULL) {
return -1;
}
buf->ptr = buf->ptr->next;
if (buf->ptr->next == NULL) {
return 1;
}
return 0;
}
/**
* Move the current data pointer of a packet buffer contained in a netbuf
* to the beginning of the packet.
* The packet buffer itself is not modified.
*
* @param buf the netbuf to modify
*/
void
netbuf_first(struct netbuf *buf)
{
LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return;);
buf->ptr = buf->p;
}
#endif /* LWIP_NETCONN */