neighbor-discovery.c

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/**
 * \addtogroup rimeneighbordiscovery
 * @{
 */

/*
 * Copyright (c) 2006, 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: neighbor-discovery.c,v 1.19 2010/03/19 13:21:48 adamdunkels Exp $
 */

/**
 * \file
 *         Neighbor discovery
 * \author
 *         Adam Dunkels <adam@sics.se>
 */

#include "contiki.h"

#include "net/rime.h"
#include "net/rime/neighbor-discovery.h"

#include "dev/radio-sensor.h"

#include "lib/random.h"

#if CONTIKI_TARGET_NETSIM
#include "ether.h"
#endif

#include <string.h>
#include <stdio.h>
#include <stddef.h>

struct adv_msg {
  uint16_t val;
};

#define DEBUG 0
#if DEBUG
#include <stdio.h>
#define PRINTF(...) printf(__VA_ARGS__)
#else
#define PRINTF(...)
#endif

/*---------------------------------------------------------------------------*/
static void
send_adv(void *ptr)
{
  struct neighbor_discovery_conn *c = ptr;
  struct adv_msg *hdr;

  packetbuf_clear();
  packetbuf_set_datalen(sizeof(struct adv_msg));
  hdr = packetbuf_dataptr();
  hdr->val = c->val;
  broadcast_send(&c->c);
  if(c->u->sent) {
    c->u->sent(c);
  }
  PRINTF("%d.%d: sending neighbor advertisement with val %d\n",
         rimeaddr_node_addr.u8[0], rimeaddr_node_addr.u8[1],
         c->val);
}
/*---------------------------------------------------------------------------*/
static void
adv_packet_received(struct broadcast_conn *ibc, const rimeaddr_t *from)
{
  struct neighbor_discovery_conn *c = (struct neighbor_discovery_conn *)ibc;
  struct adv_msg msg;

  memcpy(&msg, packetbuf_dataptr(), sizeof(struct adv_msg));

  PRINTF("%d.%d: adv_packet_received from %d.%d with val %d\n",
         rimeaddr_node_addr.u8[0], rimeaddr_node_addr.u8[1],
         from->u8[0], from->u8[1], msg.val);
  
  /* If we receive an announcement with a lower value than ours, we
     cancel our own announcement. */
  if(msg.val < c->val) {
    /*    ctimer_stop(&c->send_timer);*/
  }

  if(c->u->recv) {
    c->u->recv(c, from, msg.val);
  }
}
/*---------------------------------------------------------------------------*/
static void
adv_packet_sent(struct broadcast_conn *bc, int status, int num_tx)
{
}
/*---------------------------------------------------------------------------*/
static void send_timer(void *ptr);

static void
set_timers(struct neighbor_discovery_conn *c)
{
  ctimer_set(&c->interval_timer, c->current_interval, send_timer, c);
  ctimer_set(&c->send_timer, c->current_interval / 2 + random_rand() %
             (c->current_interval / 2),
             send_adv, c);
}
/*---------------------------------------------------------------------------*/
static void
send_timer(void *ptr)
{
  struct neighbor_discovery_conn *c = ptr;
  clock_time_t interval;

  interval = c->current_interval * 2;

  if(interval > c->max_interval) {
    interval = c->max_interval;
  }

  c->current_interval = interval;

  /*  printf("current_interval %lu\n", (long unsigned int) interval);*/

  PRINTF("current_interval %lu\n", (long unsigned int) interval);

  set_timers(c);
}
/*---------------------------------------------------------------------------*/
static CC_CONST_FUNCTION struct broadcast_callbacks broadcast_callbacks =
  {adv_packet_received, adv_packet_sent };
/*---------------------------------------------------------------------------*/
void
neighbor_discovery_open(struct neighbor_discovery_conn *c, uint16_t channel,
                        clock_time_t initial,
                        clock_time_t min,
                        clock_time_t max,
                        const struct neighbor_discovery_callbacks *cb)
{
  PRINTF("%d.%d: neighbor discovery open channel %d\n",
         rimeaddr_node_addr.u8[0], rimeaddr_node_addr.u8[1],
         channel);
  broadcast_open(&c->c, channel, &broadcast_callbacks);
  c->u = cb;
  c->initial_interval = initial;
  c->min_interval = min;
  c->max_interval = max;
}
/*---------------------------------------------------------------------------*/
void
neighbor_discovery_close(struct neighbor_discovery_conn *c)
{
  broadcast_close(&c->c);
  ctimer_stop(&c->send_timer);
  ctimer_stop(&c->interval_timer);
}
/*---------------------------------------------------------------------------*/
void
neighbor_discovery_set_val(struct neighbor_discovery_conn *c, uint16_t val)
{
  c->val = val;
}
/*---------------------------------------------------------------------------*/
void
neighbor_discovery_start(struct neighbor_discovery_conn *c, uint16_t val)
{
  c->current_interval = c->initial_interval;
  c->val = val;
  set_timers(c);
}
/*---------------------------------------------------------------------------*/
/** @} */