136 lines
4.5 KiB
C
136 lines
4.5 KiB
C
/**
|
|
* \addtogroup timesynch
|
|
* @{
|
|
*/
|
|
|
|
|
|
/*
|
|
* 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: timesynch.c,v 1.9 2009/12/09 18:08:26 adamdunkels Exp $
|
|
*/
|
|
|
|
/**
|
|
* \file
|
|
* A simple time synchronization mechanism
|
|
* \author
|
|
* Adam Dunkels <adam@sics.se>
|
|
*/
|
|
|
|
#include "net/rime/timesynch.h"
|
|
#include "net/rime/packetbuf.h"
|
|
#include "net/rime.h"
|
|
#include "dev/cc2420.h"
|
|
|
|
#if TIMESYNCH_CONF_ENABLED
|
|
static int authority_level;
|
|
static rtimer_clock_t offset;
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
int
|
|
timesynch_authority_level(void)
|
|
{
|
|
return authority_level;
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
void
|
|
timesynch_set_authority_level(int level)
|
|
{
|
|
authority_level = level;
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
rtimer_clock_t
|
|
timesynch_time(void)
|
|
{
|
|
return RTIMER_NOW() + offset;
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
rtimer_clock_t
|
|
timesynch_time_to_rtimer(rtimer_clock_t synched_time)
|
|
{
|
|
return synched_time - offset;
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
rtimer_clock_t
|
|
timesynch_rtimer_to_time(rtimer_clock_t rtimer_time)
|
|
{
|
|
return rtimer_time + offset;
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
rtimer_clock_t
|
|
timesynch_offset(void)
|
|
{
|
|
return offset;
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
static void
|
|
adjust_offset(rtimer_clock_t authoritative_time, rtimer_clock_t local_time)
|
|
{
|
|
offset = offset + authoritative_time - local_time;
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
static void
|
|
incoming_packet(void)
|
|
{
|
|
if(packetbuf_totlen() != 0) {
|
|
/* We check the authority level of the sender of the incoming
|
|
packet. If the sending node has a lower authority level than we
|
|
have, we synchronize to the time of the sending node and set our
|
|
own authority level to be one more than the sending node. */
|
|
if(cc2420_authority_level_of_sender < authority_level) {
|
|
adjust_offset(cc2420_time_of_departure,
|
|
cc2420_time_of_arrival);
|
|
if(cc2420_authority_level_of_sender + 1 != authority_level) {
|
|
authority_level = cc2420_authority_level_of_sender + 1;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
#if 0
|
|
static void
|
|
periodic_authority_increase(void *ptr)
|
|
{
|
|
/* XXX the authority level should be increased over time except
|
|
for the sink node (which has authority 0). */
|
|
}
|
|
#endif
|
|
/*---------------------------------------------------------------------------*/
|
|
RIME_SNIFFER(sniffer, incoming_packet, NULL);
|
|
/*---------------------------------------------------------------------------*/
|
|
void
|
|
timesynch_init(void)
|
|
{
|
|
rime_sniffer_add(&sniffer);
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
#endif /* TIMESYNCH_CONF_ENABLED */
|
|
/** @} */
|