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136 lines
4.5 KiB
C
136 lines
4.5 KiB
C
/**
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* \addtogroup timesynch
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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: timesynch.c,v 1.8 2009/03/17 09:57:01 nifi Exp $
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*/
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/**
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* \file
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* A simple time synchronization mechanism
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* \author
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* Adam Dunkels <adam@sics.se>
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*/
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#include "net/rime/timesynch.h"
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#include "net/rime/packetbuf.h"
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#include "net/rime.h"
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#include "dev/cc2420.h"
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#if TIMESYNCH_CONF_ENABLED
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static int authority_level;
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static rtimer_clock_t offset;
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/*---------------------------------------------------------------------------*/
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int
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timesynch_authority_level(void)
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{
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return authority_level;
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}
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/*---------------------------------------------------------------------------*/
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void
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timesynch_set_authority_level(int level)
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{
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authority_level = level;
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}
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/*---------------------------------------------------------------------------*/
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rtimer_clock_t
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timesynch_time(void)
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{
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return rtimer_arch_now() + offset;
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}
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/*---------------------------------------------------------------------------*/
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rtimer_clock_t
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timesynch_time_to_rtimer(rtimer_clock_t synched_time)
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{
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return synched_time - offset;
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}
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/*---------------------------------------------------------------------------*/
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rtimer_clock_t
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timesynch_rtimer_to_time(rtimer_clock_t rtimer_time)
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{
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return rtimer_time + offset;
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}
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/*---------------------------------------------------------------------------*/
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rtimer_clock_t
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timesynch_offset(void)
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{
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return offset;
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}
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/*---------------------------------------------------------------------------*/
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static void
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adjust_offset(rtimer_clock_t authoritative_time, rtimer_clock_t local_time)
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{
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offset = offset + authoritative_time - local_time;
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}
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/*---------------------------------------------------------------------------*/
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static void
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incoming_packet(void)
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{
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if(packetbuf_totlen() != 0) {
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/* We check the authority level of the sender of the incoming
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packet. If the sending node has a lower authority level than we
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have, we synchronize to the time of the sending node and set our
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own authority level to be one more than the sending node. */
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if(cc2420_authority_level_of_sender < authority_level) {
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adjust_offset(cc2420_time_of_departure,
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cc2420_time_of_arrival);
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if(cc2420_authority_level_of_sender + 1 != authority_level) {
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authority_level = cc2420_authority_level_of_sender + 1;
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}
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}
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}
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}
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/*---------------------------------------------------------------------------*/
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#if 0
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static void
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periodic_authority_increase(void *ptr)
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{
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/* XXX the authority level should be increased over time except
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for the sink node (which has authority 0). */
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}
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#endif
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/*---------------------------------------------------------------------------*/
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RIME_SNIFFER(sniffer, incoming_packet, NULL);
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/*---------------------------------------------------------------------------*/
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void
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timesynch_init(void)
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{
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rime_sniffer_add(&sniffer);
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}
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/*---------------------------------------------------------------------------*/
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#endif /* TIMESYNCH_CONF_ENABLED */
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/** @} */
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