osd-contiki/core/net/rime/trickle.c

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/**
* \addtogroup trickle
* @{
*/
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/*
* 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.
*
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* $Id: trickle.c,v 1.4 2007/03/31 18:31:29 adamdunkels Exp $
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*/
/**
* \file
* Trickle (reliable single source flooding) for Rime
* \author
* Adam Dunkels <adam@sics.se>
*/
#include "net/rime/trickle.h"
struct trickle_hdr {
u8_t seqno;
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u8_t interval;
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};
#define K 1
#define INTERVAL_MIN 1
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#define INTERVAL_MAX 4
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#define SEQNO_LT(a, b) ((signed char)((a) - (b)) < 0)
static int trickle_pt(struct trickle_conn *c);
/*---------------------------------------------------------------------------*/
static void
send(struct trickle_conn *c)
{
struct trickle_hdr *hdr;
if(c->q != NULL) {
queuebuf_to_rimebuf(c->q);
rimebuf_hdralloc(sizeof(struct trickle_hdr));
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hdr = rimebuf_hdrptr();
hdr->seqno = c->seqno;
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hdr->interval = c->interval;
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abc_send(&c->c);
}
}
/*---------------------------------------------------------------------------*/
static void
set_intervaltimer(struct trickle_conn *c)
{
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ctimer_set(&c->intervaltimer,
CLOCK_SECOND * (c->interval << c->interval_scaling) /
TRICKLE_SECOND,
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(void (*)(void *))trickle_pt, c);
}
/*---------------------------------------------------------------------------*/
static void
set_listentimer(struct trickle_conn *c)
{
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ctimer_set(&c->timer,
CLOCK_SECOND * (c->interval << c->interval_scaling) /
(2 * TRICKLE_SECOND),
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(void (*)(void *))trickle_pt, c);
}
/*---------------------------------------------------------------------------*/
static void
set_transmittimer(struct trickle_conn *c)
{
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clock_time_t tval;
tval = CLOCK_SECOND * (c->interval << c->interval_scaling) /
(2 * TRICKLE_SECOND);
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ctimer_set(&c->timer, random_rand() & tval,
(void (*)(void *))trickle_pt, c);
}
/*---------------------------------------------------------------------------*/
static void
reset_interval(struct trickle_conn *c)
{
PT_INIT(&c->pt);
trickle_pt(c);
}
/*---------------------------------------------------------------------------*/
static void
recv(struct abc_conn *abc)
{
struct trickle_conn *c = (struct trickle_conn *)abc;
struct trickle_hdr *hdr = rimebuf_dataptr();
rimebuf_hdrreduce(sizeof(struct trickle_hdr));
if(hdr->seqno == c->seqno) {
c->count++;
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c->cb->recv(c);
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} else if(SEQNO_LT(hdr->seqno, c->seqno)) {
send(c);
} else { /* hdr->seqno > c->seqno */
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c->interval = hdr->interval;
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c->seqno = hdr->seqno;
/* Store the incoming data in the queuebuf */
if(c->q != NULL) {
queuebuf_free(c->q);
}
c->q = queuebuf_new_from_rimebuf();
reset_interval(c);
c->cb->recv(c);
}
}
/*---------------------------------------------------------------------------*/
static int
trickle_pt(struct trickle_conn *c)
{
PT_BEGIN(&c->pt);
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c->interval_scaling = INTERVAL_MIN;
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while(1) {
c->count = 0;
set_intervaltimer(c);
set_listentimer(c);
PT_YIELD(&c->pt); /* Wait for listen timer to expire. */
set_transmittimer(c);
PT_YIELD(&c->pt); /* Wait for transmit timer to expire. */
if(c->count < K) {
send(c);
}
PT_YIELD(&c->pt); /* Wait for interval timer to expire. */
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c->interval_scaling++;
if(c->interval_scaling > INTERVAL_MAX) {
c->interval_scaling = INTERVAL_MAX;
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}
}
PT_END(&c->pt);
}
/*---------------------------------------------------------------------------*/
static const struct abc_callbacks abc = {recv};
/*---------------------------------------------------------------------------*/
void
trickle_open(struct trickle_conn *c, u16_t channel,
const struct trickle_callbacks *cb)
{
abc_open(&c->c, channel, &abc);
c->cb = cb;
c->q = NULL;
c->count = 0;
}
/*---------------------------------------------------------------------------*/
void
trickle_close(struct trickle_conn *c)
{
abc_close(&c->c);
ctimer_stop(&c->intervaltimer);
ctimer_stop(&c->timer);
}
/*---------------------------------------------------------------------------*/
void
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trickle_send(struct trickle_conn *c, u8_t interval)
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{
if(c->q != NULL) {
queuebuf_free(c->q);
}
c->q = queuebuf_new_from_rimebuf();
c->seqno++;
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c->interval = interval;
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reset_interval(c);
}
/*---------------------------------------------------------------------------*/
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/** @} */