194 lines
7 KiB
C
194 lines
7 KiB
C
/**
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* \addtogroup rime
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* @{
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*/
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/**
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* \defgroup rimepolite Polite anonymous best effort local broadcast
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* @{
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*
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* The polite module sends one local area broadcast packet within one
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* time interval. If a packet with the same header is received from a
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* neighbor within the interval, the packet is not sent.
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*
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* The polite primitive is a generalization of the polite gossip
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* algorithm from Trickle (Levis et al, NSDI 2004). The polite gossip
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* algorithm is designed to reduce the total amount of packet
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* transmissions by not repeating a message that other nodes have
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* already sent. The purpose of the polite broadcast primitive is to
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* avoid that multiple copies of a specific set of packet attributes
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* is sent on a specified logical channel in the local neighborhood
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* during a time interval.
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*
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* The polite broadcast primitive is useful for implementing broadcast
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* protocols that use, e.g., negative acknowledgements. If many nodes
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* need to send the negative acknowledgement to a sender, it is enough
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* if only a single message is delivered to the sender.
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*
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* The upper layer protocol or application that uses the polite
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* broadcast primitive provides an interval time, and message along
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* with a list of packet attributes for which multiple copies should
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* be avoided. The polite broadcast primitive stores the outgoing
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* message in a queue buffer, stores the list of packet attributes,
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* and sets up a timer. The timer is set to a random time during the
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* second half of the interval time.
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*
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* During the first half of the time interval, the sender listens for
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* other transmissions. If it hears a packet that matches the
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* attributes provided by the upper layer protocol or application, the
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* sender drops the packet. The send timer has been set to a random
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* time some time during the second half of the interval. When the
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* timer fires, and the sender has not yet heard a transmission of the
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* same packet attributes, the sender broadcasts its packet to all its
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* neighbors.
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*
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* The polite broadcast module does not add any packet attributes to
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* outgoing packets apart from those added by the upper layer.
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*
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* \section channels Channels
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*
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* The polite module uses 1 channel.
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*
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*/
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/*
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* Copyright (c) 2007, Swedish Institute of Computer Science.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file is part of the Contiki operating system.
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*
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* $Id: polite.h,v 1.6 2009/03/07 11:15:46 adamdunkels Exp $
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*/
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/**
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* \file
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* Header file for Polite Anonymous best effort local Broadcast (polite)
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* \author
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* Adam Dunkels <adam@sics.se>
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*/
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#ifndef __POLITE_H__
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#define __POLITE_H__
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#include "net/rime/abc.h"
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#include "net/rime/queuebuf.h"
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#include "net/rime/ctimer.h"
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struct polite_conn;
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#define POLITE_ATTRIBUTES ABC_ATTRIBUTES
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/**
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* \brief A structure with callback functions for a polite connection.
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*
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* This structure holds a list of callback functions used
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* a a polite connection. The functions are called when
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* events occur on the connection.
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*
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*/
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struct polite_callbacks {
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/**
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* Called when a packet is received on the connection.
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*/
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void (* recv)(struct polite_conn *c);
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/**
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* Called when a packet is sent on the connection.
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*/
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void (* sent)(struct polite_conn *c);
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/**
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* Called when a packet is dropped because a packet was heard from a
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* neighbor.
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*/
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void (* dropped)(struct polite_conn *c);
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};
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/**
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* An opaque structure with no user-visible elements that holds the
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* state of a polite connection,
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*/
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struct polite_conn {
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struct abc_conn c;
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const struct polite_callbacks *cb;
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struct ctimer t;
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struct queuebuf *q;
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uint8_t hdrsize;
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};
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/**
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* \brief Open a polite connection
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* \param c A pointer to a struct polite_conn.
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* \param channel The channel number to be used for this connection
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* \param cb A pointer to the callbacks used for this connection
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*
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* This function opens a polite connection on the
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* specified channel. The callbacks are called when a
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* packet is received, or when another event occurs on the
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* connection (see \ref "struct polite_callbacks").
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*/
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void polite_open(struct polite_conn *c, uint16_t channel,
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const struct polite_callbacks *cb);
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/**
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* \brief Close a polite connection
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* \param c A pointer to a struct polite_conn that has previously been opened with polite_open().
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*
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* This function closes a polite connection that has
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* previously been opened with polite_open().
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*/
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void polite_close(struct polite_conn *c);
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/**
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* \brief Send a packet on a polite connection.
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* \param c A pointer to a struct polite_conn that has previously been opened with polite_open().
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* \param interval The timer interval in which the packet should be sent.
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* \param hdrsize The size of the header that should be unique within the time interval.
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*
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* This function sends a packet from the rimebuf on the
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* polite connection. The packet is sent some time during
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* the time interval, but only if no other packet is
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* received with the same header.
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*
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*/
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int polite_send(struct polite_conn *c, clock_time_t interval, uint8_t hdrsize);
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/**
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* \brief Cancel a pending packet
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* \param c A pointer to a struct polite_conn that has previously been opened with polite_open().
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*
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* This function cancels a pending transmission that has
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* previously been started with polite_send().
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*/
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void polite_cancel(struct polite_conn *c);
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#endif /* __POLITE_H__ */
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/** @} */
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/** @} */
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