contiki/core/net/mac/ctdma_mac.c

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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.
*
* $Id: ctdma_mac.c,v 1.4 2009/06/22 11:14:11 nifi Exp $
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*/
#include "contiki.h"
#include "net/mac/ctdma_mac.h"
#include "net/rime/packetbuf.h"
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#include "net/uip-fw.h"
#include "net/rime/ctimer.h"
#include "net/rime.h"
#include "lib/memb.h"
#include "lib/list.h"
#include "dev/leds.h"
#include "node-id.h"
#include <string.h>
#include <stdio.h>
#define DEBUG 1
#if DEBUG
#define DLEDS_ON(x) leds_on(x)
#define DLEDS_OFF(x) leds_off(x)
#define DLEDS_TOGGLE(x) leds_toggle(x)
#define PRINTF(...) printf(__VA_ARGS__)
#else
#define DLEDS_ON(x)
#define DLEDS_OFF(x)
#define DLEDS_TOGGLE(x)
#define PRINTF(...)
#endif
/* TDMA */
#define NR_SLOTS 3
#define SLOT_LENGTH (CLOCK_SECOND/3)
#define GUARD_PERIOD (CLOCK_SECOND/12)
#define MY_SLOT (node_id % NR_SLOTS)
#define PERIOD_LENGTH CLOCK_SECOND
/* Buffers */
#define NUM_PACKETS 8
uint8_t lastqueued = 0;
uint8_t nextsend = 0;
uint8_t freeslot = 0;
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struct queuebuf* data[NUM_PACKETS];
int id[NUM_PACKETS];
static struct ctimer ctimer;
uint8_t timer_on = 0;
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static const struct radio_driver *radio;
static void (* receiver_callback)(const struct mac_driver *);
static int id_counter = 0;
static int sent_counter = 0;
/*---------------------------------------------------------------------------*/
static void
transmitter(void *ptr)
{
clock_time_t now, rest, period_start, slot_start;
/* Calculate slot start time */
now = clock_time();
rest = now % PERIOD_LENGTH;
period_start = now - rest;
slot_start = period_start + MY_SLOT*SLOT_LENGTH;
/* Check if we are inside our slot */
if (now < slot_start ||
now > slot_start + SLOT_LENGTH - GUARD_PERIOD)
{
PRINTF("TIMER We are outside our slot: %u != [%u,%u]\n", now, slot_start, slot_start + SLOT_LENGTH);
while (now > slot_start + SLOT_LENGTH - GUARD_PERIOD)
{
slot_start += PERIOD_LENGTH;
}
PRINTF("TIMER Rescheduling until %u\n", slot_start);
ctimer_set(&ctimer, slot_start - clock_time(), transmitter, NULL);
return;
}
/* Transmit queued packets */
while (nextsend != freeslot)
{
PRINTF("RADIO Transmitting packet #%i\n", id[nextsend]);
if(!radio->send(
queuebuf_dataptr(data[nextsend]),
queuebuf_datalen(data[nextsend])))
{
sent_counter++;
PRINTF("RADIO Transmit OK for #%i, total=%i\n", id[nextsend], sent_counter);
DLEDS_TOGGLE(LEDS_GREEN);
}
else
{
PRINTF("RADIO Transmit failed for #%i, total=%i\n", id[nextsend], sent_counter);
DLEDS_TOGGLE(LEDS_RED);
}
nextsend = (nextsend + 1) % NUM_PACKETS;
/* Recalculate new slot */
if (clock_time() > slot_start + SLOT_LENGTH - GUARD_PERIOD)
{
PRINTF("TIMER No more time to transmit\n");
break;
}
}
/* Calculate time of our next slot */
slot_start += PERIOD_LENGTH;
PRINTF("TIMER Rescheduling until %u\n", slot_start);
ctimer_set(&ctimer, slot_start - clock_time(), transmitter, NULL);
}
/*---------------------------------------------------------------------------*/
static int
send(void)
{
id_counter++;
/* Clean up already sent packets */
while (lastqueued != nextsend)
{
PRINTF("BUFFER Cleaning up packet #%i\n", id[lastqueued]);
queuebuf_free(data[lastqueued]);
data[lastqueued] = NULL;
lastqueued = (lastqueued + 1) % NUM_PACKETS;
}
if ((freeslot + 1) % NUM_PACKETS == lastqueued)
{
PRINTF("BUFFER Buffer full, dropping packet #%i\n", (id_counter+1));
return UIP_FW_DROPPED;
}
/* Allocate queue buf for packet */
data[freeslot] = queuebuf_new_from_packetbuf();
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id[freeslot] = id_counter;
if (data[freeslot] == NULL)
{
PRINTF("BUFFER Queuebuffer full, dropping packet #%i\n", id[freeslot]);
return UIP_FW_DROPPED;
}
PRINTF("BUFFER Wrote packet #%i to buffer \n", id[freeslot]);
freeslot = (freeslot + 1) % NUM_PACKETS;
if (!timer_on)
{
PRINTF("TIMER Starting timer\n");
ctimer_set(&ctimer, CLOCK_SECOND, transmitter, NULL);
timer_on = 1;
}
return UIP_FW_OK; /* TODO Return what? */
}
/*---------------------------------------------------------------------------*/
static void
input(const struct radio_driver *d)
{
receiver_callback(&ctdma_mac_driver);
}
/*---------------------------------------------------------------------------*/
static int
read(void)
{
int len;
packetbuf_clear();
len = radio->read(packetbuf_dataptr(), PACKETBUF_SIZE);
packetbuf_set_datalen(len);
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return len;
}
/*---------------------------------------------------------------------------*/
static void
set_receive_function(void (* recv)(const struct mac_driver *))
{
receiver_callback = recv;
}
/*---------------------------------------------------------------------------*/
static int
on(void)
{
return radio->on();
}
/*---------------------------------------------------------------------------*/
static int
off(int keep_radio_on)
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{
if(keep_radio_on) {
return radio->on();
} else {
return radio->off();
}
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}
/*---------------------------------------------------------------------------*/
const struct mac_driver *
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ctdma_mac_init(const struct radio_driver *d)
{
int i;
for (i=0; i < NUM_PACKETS; i++)
{
data[i] = NULL;
}
radio = d;
radio->set_receive_function(input);
radio->on();
return &ctdma_mac_driver;
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}
/*---------------------------------------------------------------------------*/
const struct mac_driver ctdma_mac_driver = {
"CTDMA",
ctdma_mac_init,
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send,
read,
set_receive_function,
on,
off,
};