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/**

 * @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 <adam@sics.se>

 *

 */

#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 <string.h>

/**

 * 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 */