nes-proj/core/net/rime/polite.h

194 lines
7.0 KiB
C

/**
* \addtogroup rime
* @{
*/
/**
* \defgroup rimepolite Polite anonymous best effort local broadcast
* @{
*
* The polite module sends one local area broadcast packet within one
* time interval. If a packet with the same header is received from a
* neighbor within the interval, the packet is not sent.
*
* The polite primitive is a generalization of the polite gossip
* algorithm from Trickle (Levis et al, NSDI 2004). The polite gossip
* algorithm is designed to reduce the total amount of packet
* transmissions by not repeating a message that other nodes have
* already sent. The purpose of the polite broadcast primitive is to
* avoid that multiple copies of a specific set of packet attributes
* is sent on a specified logical channel in the local neighborhood
* during a time interval.
*
* The polite broadcast primitive is useful for implementing broadcast
* protocols that use, e.g., negative acknowledgements. If many nodes
* need to send the negative acknowledgement to a sender, it is enough
* if only a single message is delivered to the sender.
*
* The upper layer protocol or application that uses the polite
* broadcast primitive provides an interval time, and message along
* with a list of packet attributes for which multiple copies should
* be avoided. The polite broadcast primitive stores the outgoing
* message in a queue buffer, stores the list of packet attributes,
* and sets up a timer. The timer is set to a random time during the
* second half of the interval time.
*
* During the first half of the time interval, the sender listens for
* other transmissions. If it hears a packet that matches the
* attributes provided by the upper layer protocol or application, the
* sender drops the packet. The send timer has been set to a random
* time some time during the second half of the interval. When the
* timer fires, and the sender has not yet heard a transmission of the
* same packet attributes, the sender broadcasts its packet to all its
* neighbors.
*
* The polite broadcast module does not add any packet attributes to
* outgoing packets apart from those added by the upper layer.
*
* \section channels Channels
*
* The polite module uses 1 channel.
*
*/
/*
* Copyright (c) 2007, 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.
*
* $Id: polite.h,v 1.7 2009/03/12 21:58:21 adamdunkels Exp $
*/
/**
* \file
* Header file for Polite Anonymous best effort local Broadcast (polite)
* \author
* Adam Dunkels <adam@sics.se>
*/
#ifndef __POLITE_H__
#define __POLITE_H__
#include "net/rime/abc.h"
#include "net/rime/queuebuf.h"
#include "net/rime/ctimer.h"
struct polite_conn;
#define POLITE_ATTRIBUTES ABC_ATTRIBUTES
/**
* \brief A structure with callback functions for a polite connection.
*
* This structure holds a list of callback functions used
* a a polite connection. The functions are called when
* events occur on the connection.
*
*/
struct polite_callbacks {
/**
* Called when a packet is received on the connection.
*/
void (* recv)(struct polite_conn *c);
/**
* Called when a packet is sent on the connection.
*/
void (* sent)(struct polite_conn *c);
/**
* Called when a packet is dropped because a packet was heard from a
* neighbor.
*/
void (* dropped)(struct polite_conn *c);
};
/**
* An opaque structure with no user-visible elements that holds the
* state of a polite connection,
*/
struct polite_conn {
struct abc_conn c;
const struct polite_callbacks *cb;
struct ctimer t;
struct queuebuf *q;
uint8_t hdrsize;
};
/**
* \brief Open a polite connection
* \param c A pointer to a struct polite_conn.
* \param channel The channel number to be used for this connection
* \param cb A pointer to the callbacks used for this connection
*
* This function opens a polite connection on the
* specified channel. The callbacks are called when a
* packet is received, or when another event occurs on the
* connection (see \ref "struct polite_callbacks").
*/
void polite_open(struct polite_conn *c, uint16_t channel,
const struct polite_callbacks *cb);
/**
* \brief Close a polite connection
* \param c A pointer to a struct polite_conn that has previously been opened with polite_open().
*
* This function closes a polite connection that has
* previously been opened with polite_open().
*/
void polite_close(struct polite_conn *c);
/**
* \brief Send a packet on a polite connection.
* \param c A pointer to a struct polite_conn that has previously been opened with polite_open().
* \param interval The timer interval in which the packet should be sent.
* \param hdrsize The size of the header that should be unique within the time interval.
*
* This function sends a packet from the packetbuf on the
* polite connection. The packet is sent some time during
* the time interval, but only if no other packet is
* received with the same header.
*
*/
int polite_send(struct polite_conn *c, clock_time_t interval, uint8_t hdrsize);
/**
* \brief Cancel a pending packet
* \param c A pointer to a struct polite_conn that has previously been opened with polite_open().
*
* This function cancels a pending transmission that has
* previously been started with polite_send().
*/
void polite_cancel(struct polite_conn *c);
#endif /* __POLITE_H__ */
/** @} */
/** @} */