contiki/core/net/rime/announcement.h

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/*
* Copyright (c) 2008, 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 announcement primitive
* \author
* Adam Dunkels <adam@sics.se>
*/
/**
* \addtogroup rime
* @{
*/
/**
* \defgroup rimeannouncement Announcements
* @{
*
* The Announcement primitive does local area announcements. An
* announcement is an (ID, value) tuple that is disseminated to local
* area neighbors. An application or protocol can explicitly listen to
* announcements from neighbors. When an announcement is heard, a
* callback is invoked.
*
* Announcements can be used for a variety of network mechanisms such
* as neighbor discovery, node-level service discovery, or routing
* metric dissemination.
*
* Application programs and protocols register announcements with the
* announcement module. An announcement back-end, implemented by the
* system, takes care of sending out announcements over the radio, as
* well as collecting announcements heard from neighbors.
*
*/
#ifndef ANNOUNCEMENT_H_
#define ANNOUNCEMENT_H_
#include "net/linkaddr.h"
struct announcement;
typedef void (*announcement_callback_t)(struct announcement *a,
const linkaddr_t *from,
uint16_t id, uint16_t val);
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/**
* \brief Representation of an announcement.
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*
* This structure holds the state of an announcement. It
* is an opaque structure with no user-visible elements.
*/
struct announcement {
struct announcement *next;
uint16_t id;
uint16_t value;
announcement_callback_t callback;
uint8_t has_value;
};
/**
* \name Application API
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* @{
*/
/**
* \brief Register an announcement
* \param a A pointer to a struct announcement
* \param id The identifying number of the announcement
* \param callback A pointer to a callback function that is called
* when an announcement is heard
*
* This function registers an announcement with the
* announcement module. The state of the announcement is
* held in a struct announcement variable, which is passed
* as an argument to this function. This variable must be
* allocated by the caller. An announcement is identified
* with a 16-bit number, which is passed as a parameter to
* the function. The announcement also has an initial
* value, that can later be changed with
* announcement_set_value().
*
*/
void announcement_register(struct announcement *a,
uint16_t id,
announcement_callback_t callback);
/**
* \brief Remove a previously registered announcement
* \param a A pointer to a struct announcement that has
* previously been registered
*
* This function removes an announcement that has
* previously been registered with
* announcement_register().
*
*/
void announcement_remove(struct announcement *a);
/**
* \brief Set the value of an announcement
* \param a A pointer to a struct announcement that has
* previously been registered
* \param value The new value
*
* This function sets the value of an announcement that
* has previously been registered with
* announcement_register().
*
*/
void announcement_set_value(struct announcement *a, uint16_t value);
/**
* \brief Remove the value of an announcement
* \param a A pointer to a struct announcement that has
* previously been registered
*
* This function removes the value of an announcement that
* has previously been registered with
* announcement_register().
*
*/
void announcement_remove_value(struct announcement *a);
/**
* \brief Bump an announcement
* \param a A pointer to a struct announcement that has
* previously been registered
*
* This function is called to inform the announcement
* module that a particular announcement has changed in a
* way that it should be bumped. When an announcement is
* bumped, the announcement back-end may send out a new
* announcement to neighbors.
*
*/
void announcement_bump(struct announcement *a);
/**
* \brief Listen for announcements for a specific amount of
* announcement periods
* \param periods The number of periods to listen for announcement
*
* This function starts to listen for announcements for
* the specified amount of announcement periods. This
* function is called to ensure that the announcement
* module hears announcements from neighbors. The
* announcement module may hear announcements even if
* listening is not explicitly enabled, but with listening
* enabled, more announcements will be heard.
*
*/
void announcement_listen(int periods);
/**
* @}
*/
/**
* \name System API
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* @{
*/
/**
* \brief Initialize the announcement module
*
* This function initializes the announcement module, and
* is called by the system at boot up.
*/
void announcement_init(void);
/**
* \brief Get the list of registered announcements
* \return The list of registered announcements
*
* This function returns the list of registered
* announcements. This function is used by the back-end to
* compile announcement packets from the registered
* announcements.
*
* The announcement list is an ordinary Contiki list, as
* defined by the \ref list "list module".
*
*/
struct announcement *announcement_list(void);
/**
* \brief Inform the announcement module of an incoming announcement
* \param from The address of the sender of the announcement
* \param id The identifier of the announcement
* \param value The value of the announcement
*
* This function is called by the back-end to inform the
* announcement module that an announcement from a
* neighbor has been heard.
*
*/
void announcement_heard(const linkaddr_t *from, uint16_t id, uint16_t value);
/**
* \brief Register a listen callback with the announcement module
* \param callback A pointer to a callback function
*
* This function is called by the back-end to register a
* listen callback with the announcement module. The
* listen callback function is called by the announcement
* module as part of the announcement_listen() function.
*
*/
void announcement_register_listen_callback(void (*callback)(int time));
enum {
ANNOUNCEMENT_NOBUMP,
ANNOUNCEMENT_BUMP,
};
typedef void (* announcement_observer)(uint16_t id, uint8_t has_value,
uint16_t newvalue, uint16_t oldvalue,
uint8_t bump);
/**
* \brief Register an observer callback with the announcement module
* \param observer A pointer to an observer function
*
* This function is callback by the back-end to register
* an observer callback with the announcement module. The
* observer callback is called by the announcement module
* when an announcement is registered, removed, or have
* its identifier or value updated.
*
* The back-end may chose to send out a new announcement
* message with the updated values.
*
*/
void announcement_register_observer_callback(announcement_observer observer);
/**
* @}
*/
#endif /* ANNOUNCE_H_ */
/** @} */
/** @} */