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/*

 * 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>

 *

 */

#ifndef __LWIP_PBUF_H__

#define __LWIP_PBUF_H__

#include "arch/cc.h"

#define PBUF_TRANSPORT_HLEN 20

#define PBUF_IP_HLEN        20

typedef enum {

  PBUF_TRANSPORT,

  PBUF_IP,

  PBUF_LINK,

  PBUF_RAW

} pbuf_layer;

typedef enum {

  PBUF_RAM,

  PBUF_ROM,

  PBUF_REF,

  PBUF_POOL

} pbuf_flag;

/* Definitions for the pbuf flag field. These are NOT the flags that

 * are passed to pbuf_alloc(). */

#define PBUF_FLAG_RAM   0x00U    /* Flags that pbuf data is stored in RAM */

#define PBUF_FLAG_ROM   0x01U    /* Flags that pbuf data is stored in ROM */

#define PBUF_FLAG_POOL  0x02U    /* Flags that the pbuf comes from the pbuf pool */

#define PBUF_FLAG_REF   0x04U    /* Flags thet the pbuf payload refers to RAM */

/** indicates this packet was broadcast on the link */

#define PBUF_FLAG_LINK_BROADCAST 0x80U

struct pbuf {

  /** next pbuf in singly linked pbuf chain */

  struct pbuf *next;

  /** pointer to the actual data in the buffer */

  void *payload;

  /**

   * total length of this buffer and all next buffers in chain

   * belonging to the same packet.

   *

   * For non-queue packet chains this is the invariant:

   * p->tot_len == p->len + (p->next? p->next->tot_len: 0)

   */

  u16_t tot_len;

  /** length of this buffer */

  u16_t len;

  /** flags telling the type of pbuf, see PBUF_FLAG_ */

  u16_t flags;

  /**

   * the reference count always equals the number of pointers

   * that refer to this pbuf. This can be pointers from an application,

   * the stack itself, or pbuf->next pointers from a chain.

   */

  u16_t ref;

};

void pbuf_init(void);

struct pbuf *pbuf_alloc(pbuf_layer l, u16_t size, pbuf_flag flag);

void pbuf_realloc(struct pbuf *p, u16_t size);

u8_t pbuf_header(struct pbuf *p, s16_t header_size);

void pbuf_ref(struct pbuf *p);

void pbuf_ref_chain(struct pbuf *p);

u8_t pbuf_free(struct pbuf *p);

u8_t pbuf_clen(struct pbuf *p);

void pbuf_cat(struct pbuf *h, struct pbuf *t);

void pbuf_chain(struct pbuf *h, struct pbuf *t);

struct pbuf *pbuf_take(struct pbuf *f);

struct pbuf *pbuf_dechain(struct pbuf *p);

void pbuf_queue(struct pbuf *p, struct pbuf *n);

struct pbuf * pbuf_dequeue(struct pbuf *p);

#endif /* __LWIP_PBUF_H__ */