contiki/core/net/rime/packetqueue.h

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/*
* Copyright (c) 2009, 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. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``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 INSTITUTE OR CONTRIBUTORS 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 Contiki operating system.
*
*/
/**
* \file
* Header file for the packetqueue module
* \author
* Adam Dunkels <adam@sics.se>
*/
/**
* \addtogroup rime
* @{
*/
/**
* \defgroup packetqueue Packet queue
* @{
*
* The packetqueue module handles a list of queued packets.
*
*/
#ifndef PACKETQUEUE_H_
#define PACKETQUEUE_H_
#include "lib/list.h"
#include "lib/memb.h"
#include "sys/ctimer.h"
#include "net/packetbuf.h"
#include "net/queuebuf.h"
/**
* \brief Representation of a packet queue.
*
* This structure holds the state of a packet queue. It is
* an opaque structure with no user-visible elements.
*/
struct packetqueue {
list_t *list;
struct memb *memb;
};
/**
* \brief Representation of an item in a packet queue.
*
* This structure holds the state of a packet queue. It is
* an opaque structure with no user-visible elements. The
* function packetqueue_queuebuf() is used to extract a
* "queubuf" from the item. The function
* packetqueue_ptr() is used to extract the opaque pointer
* that was registered with the
* packetqueue_enqueue_packetbuf() function.
*/
struct packetqueue_item {
struct packetqueue_item *next;
struct queuebuf *buf;
struct packetqueue *queue;
struct ctimer lifetimer;
void *ptr;
};
/**
* \brief Define a packet queue.
* \param name The variable name of the packet queue
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* \param size The maximum size of the packet queue
*
* This statement defines a packet queue. A packet queue
* is defined on a per-module basis.
*
*/
#define PACKETQUEUE(name, size) LIST(name##_list); \
MEMB(name##_memb, struct packetqueue_item, size); \
static struct packetqueue name = { &name##_list, \
&name##_memb }
/**
* \name Packet queue functions.
* @{
*/
/**
* \brief Initialize a packet queue.
* \param q A pointer to a struct packetqueue that was defined with PACKETQUEUE().
*
* This function initializes a packetqueue that has
* previously been defined with PACKETQUEUE().
*
*/
void packetqueue_init(struct packetqueue *q);
/**
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* \brief Enqueue a packetbuf on a packet queue.
* \param q A pointer to a struct packetqueue.
* \param lifetime The maximum time that the packet should stay in the packet queue, or zero if the packet should stay on the packet queue indefinitely.
* \param ptr An opaque, user-defined pointer that can be used to identify the packet when it later is dequeued.
* \retval Zero If memory could not be allocated for the packet.
* \retval Non-zero If the packet was successfully enqueued.
*
*
* This function enqueues the \ref packetbuf "packetbuf"
* to the packet queue pointed to by the q parameter. The
* packet queue must previously have been defined with
* PACKETQUEUE() and initialized with packetqueue_init().
*
* Each packet queue item has a maximum lifetime. When the
* lifetime expires, the packet queue item is
* automatically removed from the packet queue. If the
* lifetime parameter is given as zero, the packet never
* times out from the packet queue.
*
* Each packet queue item is tagged with a user-defined
* pointer. This pointer can be used to identify packets
* as they later are dequeued from the queue. This is
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* useful if two modules is using the same packet queue:
* the modules can use the pointer to distinguish to which
* module a dequeued packet belongs.
*
*/
int packetqueue_enqueue_packetbuf(struct packetqueue *q, clock_time_t lifetime,
void *ptr);
/**
* \brief Access the first item on the packet buffer.
* \param q A pointer to a struct packetqueue.
* \return A pointer to the first item on the packet queue.
*
* This function returns the first item on the packet
* queue. The packet queue is unchanged by this
* function. To dequeue the first item on the list, use
* the packetqueue_dequeue() function.
*
*/
struct packetqueue_item *packetqueue_first(struct packetqueue *q);
/**
* \brief Remove the first item on the packet buffer.
* \param q A pointer to a struct packetqueue.
*
* This function removes the first item on the packet
* queue. The function does not return the first item: to
* access the first item, the packetqueue_first() function
* must have been used prior to calling
* packetqueue_dequeue().
*
*/
void packetqueue_dequeue(struct packetqueue *q);
/**
* \brief Get the length of the packet queue
* \param q A pointer to a struct packetqueue.
* \return The number of packets queued on the packet queue
*
* This function returns the number of packets that are
* queued on the packet queue.
*
*/
int packetqueue_len(struct packetqueue *q);
/**
* @}
*/
/**
* \name Packet queue item functions
* @{
*/
/**
* \brief Access the queuebuf in a packet queue item.
* \param i A packet queue item, obtained with packetqueue_first().
* \return A pointer to the queuebuf in the packet queue item.
*/
struct queuebuf *packetqueue_queuebuf(struct packetqueue_item *i);
/**
* \brief Access the user-defined pointer in a packet queue item.
* \param i A packet queue item, obtained with packetqueue_first().
* \return A pointer to the user-defined pointer in the packet queue item.
*/
void *packetqueue_ptr(struct packetqueue_item *i);
/**
* @}
*/
#endif /* PACKETQUEUE_H_ */
/** @} */
/** @} */