xmac.c

Contiki是一个开源

/*
 * 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: xmac.c,v 1.21 2008/09/04 17:44:01 adamdunkels Exp $
 */

/**
 * \file
 *         A simple power saving MAC protocol based on X-MAC [SenSys 2006]
 * \author
 *         Adam Dunkels <[e-mail]>
 */

#include "sys/pt.h"
#include "net/mac/xmac.h"
#include "sys/rtimer.h"
#include "dev/leds.h"
#include "net/rime.h"
#include "net/rime/timesynch.h"
#include "dev/radio.h"
#include "dev/watchdog.h"
#include "lib/random.h"
/*#include "lib/bb.h"*/

#include "sys/timetable.h"

#include "contiki-conf.h"

#if CHAMELEON
#include "net/chameleon/packattr.h"
#endif

#define WITH_TIMETABLE 0
#define WITH_CHANNEL_CHECK 0   /* Seems to work badly when enabled */
#define WITH_TIMESYNCH 0
#define WITH_QUEUE 0

struct xmac_hdr {
  rimeaddr_t sender;
  rimeaddr_t receiver;
};

#ifdef XMAC_CONF_ON_TIME
#define DEFAULT_ON_TIME (XMAC_CONF_ON_TIME)
#else
#define DEFAULT_ON_TIME (RTIMER_ARCH_SECOND / 200)
#endif

#ifdef XMAC_CONF_OFF_TIME
#define DEFAULT_OFF_TIME (XMAC_CONF_OFF_TIME)
#else
#define DEFAULT_OFF_TIME (RTIMER_ARCH_SECOND / 2 - DEFAULT_ON_TIME)
#endif

#define DEFAULT_STROBE_WAIT_TIME (7 * DEFAULT_ON_TIME / 8)

struct xmac_config xmac_config = {
  DEFAULT_ON_TIME,
  DEFAULT_OFF_TIME,
  20 * DEFAULT_ON_TIME + DEFAULT_OFF_TIME,
  DEFAULT_STROBE_WAIT_TIME
};

#include <stdio.h>
static struct rtimer rt;
static struct pt pt;

static int xmac_is_on = 0;

static volatile unsigned char waiting_for_packet = 0;
static volatile unsigned char someone_is_sending = 0;
static volatile unsigned char we_are_sending = 0;
static volatile unsigned char radio_is_on = 0;

static const struct radio_driver *radio;

#undef LEDS_ON
#undef LEDS_OFF
#undef LEDS_TOGGLE


#define CPRINTF(...)

#define BB_SET(x,y)
#define BB_INC(x,y)
/* #define BB_SET(x,y) bb_set(x,y) */
/* #define BB_INC(x,y) bb_inc(x,y) */
#define LEDS_ON(x) leds_on(x)
#define LEDS_OFF(x) leds_off(x)
#define LEDS_TOGGLE(x) leds_toggle(x)
#define DEBUG 0
#if DEBUG
#include <stdio.h>
#define PRINTF(...) printf(__VA_ARGS__)
#else
#undef LEDS_ON
#undef LEDS_OFF
#undef LEDS_TOGGLE
#define LEDS_ON(x)
#define LEDS_OFF(x)
#define LEDS_TOGGLE(x)
#define PRINTF(...)
#endif

static void (* receiver_callback)(const struct mac_driver *);

#if WITH_TIMETABLE
#define xmac_timetable_size 1024
TIMETABLE_NONSTATIC(xmac_timetable);
#endif /* WITH_TIMETABLE */
/*---------------------------------------------------------------------------*/
static void
set_receive_function(void (* recv)(const struct mac_driver *))
{
  receiver_callback = recv;
}
/*---------------------------------------------------------------------------*/
static void
on(void)
{
  if(xmac_is_on && radio_is_on == 0) {
    radio_is_on = 1;
    radio->on();
    LEDS_ON(LEDS_RED);
    CPRINTF("/");
#if WITH_TIMETABLE
    TIMETABLE_TIMESTAMP(xmac_timetable, "on");
#endif
  }
}
/*---------------------------------------------------------------------------*/
static void
off(void)
{
  if(xmac_is_on && radio_is_on != 0) {
    radio_is_on = 0;
    radio->off();
#if WITH_TIMETABLE
    TIMETABLE_TIMESTAMP(xmac_timetable, "off");
#endif
    LEDS_OFF(LEDS_RED);
    CPRINTF("\\");
  }
}
/*---------------------------------------------------------------------------*/
static char
powercycle(struct rtimer *t, void *ptr)
{
  int r;
#if WITH_TIMESYNCH
  rtimer_clock_t should_be, adjust;
#endif /* WITH_TIMESYNCH */

  CPRINTF("*");
  
  PT_BEGIN(&pt);

  while(1) {
    /* Only wait for some cycles to pass for someone to start sending */
    if(someone_is_sending > 0) {
      someone_is_sending--;
    }

    if(xmac_config.off_time > 0) {
      if(waiting_for_packet == 0) {
	if(we_are_sending == 0) {
	  off();
	}
      } else {
	waiting_for_packet++;
	if(waiting_for_packet > 2) {
	  /* We should not be awake for more than two consecutive
	     power cycles without having heard a packet, so we turn off
	     the radio. */
	  waiting_for_packet = 0;
#if WITH_TIMETABLE
	  TIMETABLE_TIMESTAMP(xmac_timetable, "off waiting");
#endif
	  off();
	}
      }

#if WITH_TIMESYNCH
#define NUM_SLOTS 8
      should_be = ((timesynch_rtimer_to_time(RTIMER_TIME(t)) +
		    xmac_config.off_time) &
		   ~(xmac_config.off_time + xmac_config.on_time - 1)) +
	(rimeaddr_node_addr.u8[0] % NUM_SLOTS *
	 ((xmac_config.off_time + xmac_config.on_time) / NUM_SLOTS));

      should_be = timesynch_time_to_rtimer(should_be);

      if(should_be - RTIMER_TIME(t) > xmac_config.off_time) {
	adjust = xmac_config.off_time / 2;
      } else {
	adjust = should_be - RTIMER_TIME(t);
      }
      r = rtimer_set(t, RTIMER_TIME(t) + adjust, 1,
		     (void (*)(struct rtimer *, void *))powercycle, ptr);
#else /* WITH_TIMESYNCH */
      r = rtimer_set(t, RTIMER_TIME(t) + xmac_config.off_time, 1,
		     (void (*)(struct rtimer *, void *))powercycle, ptr);
#endif /* WITH_TIMESYNCH */
      if(r) {
	PRINTF("xmac: 1 could not set rtimer %d\n", r);
      }
      PT_YIELD(&pt);
    }

    if(we_are_sending == 0 &&
       waiting_for_packet == 0) {
      on();
    }
    r = rtimer_set(t, RTIMER_TIME(t) + xmac_config.on_time, 1,
		   (void (*)(struct rtimer *, void *))powercycle, ptr);
    if(r) {
      PRINTF("xmac: 3 could not set rtimer %d\n", r);
    }

    PT_YIELD(&pt);
  }

  PT_END(&pt);
}
/*---------------------------------------------------------------------------*/
static int
send_packet(void)
{
  rtimer_clock_t t0;
  rtimer_clock_t t;
  int strobes;
  struct xmac_hdr *hdr;
  int got_ack = 0;
  struct xmac_hdr msg;
  int len;
  int is_broadcast = 0;

#if WITH_TIMETABLE
  TIMETABLE_TIMESTAMP(xmac_timetable, "send");
#endif
  
#if WITH_CHANNEL_CHECK
  /* Check if there are other strobes in the air. */
  waiting_for_packet = 1;
  on();
  t0 = RTIMER_NOW();
  while(RTIMER_CLOCK_LT(RTIMER_NOW(), t0 + xmac_config.strobe_wait_time * 2)) {
    len = radio->read(&msg, sizeof(msg));
    if(len > 0) {
      someone_is_sending = 1;
    }
  }
  waiting_for_packet = 0;
  
  while(someone_is_sending); /* {printf("z");}*/

#if WITH_TIMETABLE
  TIMETABLE_TIMESTAMP(xmac_timetable, "send 2");
#endif /* WITH_TIMETABLE */
  
#endif /* WITH_CHANNEL_CHECK */
  
  /* By setting we_are_sending to one, we ensure that the rtimer
     powercycle interrupt do not interfere with us sending the packet. */
  we_are_sending = 1;

  off();

  
  rimebuf_hdralloc(sizeof(struct xmac_hdr));
  hdr = rimebuf_hdrptr();