208 lines
6 KiB
C
208 lines
6 KiB
C
/*
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* Copyright (c) 2006, Swedish Institute of Computer Science.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file is part of the Contiki operating system.
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*
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* $Id: neighbor.c,v 1.3 2007/03/15 19:43:07 adamdunkels Exp $
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*/
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/**
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* \file
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* Radio neighborhood management
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* \author
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* Adam Dunkels <adam@sics.se>
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*/
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#include <limits.h>
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#include "contiki.h"
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#include "net/rime/neighbor.h"
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#define MAX_NEIGHBORS 5
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#define HOPCOUNT_MAX 32
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static struct neighbor neighbors[MAX_NEIGHBORS];
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/*---------------------------------------------------------------------------*/
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void
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neighbor_periodic(int max_time)
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{
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int i;
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for(i = 0; i < MAX_NEIGHBORS; ++i) {
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if(!rimeaddr_cmp(&neighbors[i].addr, &rimeaddr_null) &&
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neighbors[i].time < max_time) {
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neighbors[i].time++;
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if(neighbors[i].time == max_time) {
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neighbors[i].hopcount = HOPCOUNT_MAX;
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/* printf("%d: removing old neighbor %d\n", node_id, neighbors[i].nodeid);*/
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rimeaddr_copy(&neighbors[i].addr, &rimeaddr_null);
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}
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}
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}
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}
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/*---------------------------------------------------------------------------*/
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void
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neighbor_init(void)
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{
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int i;
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for(i = 0; i < MAX_NEIGHBORS; ++i) {
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rimeaddr_copy(&neighbors[i].addr, &rimeaddr_null);
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}
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}
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/*---------------------------------------------------------------------------*/
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struct neighbor *
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neighbor_find(rimeaddr_t *addr)
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{
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int i;
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for(i = 0; i < MAX_NEIGHBORS; ++i) {
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if(rimeaddr_cmp(&neighbors[i].addr, addr)) {
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return &neighbors[i];
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}
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}
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return NULL;
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}
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/*---------------------------------------------------------------------------*/
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void
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neighbor_update(struct neighbor *n, u8_t hopcount, u16_t signal)
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{
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if(n != NULL) {
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n->hopcount = hopcount;
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n->signal = signal;
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n->time = 0;
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}
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}
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/*---------------------------------------------------------------------------*/
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void
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neighbor_add(rimeaddr_t *addr, u8_t nhopcount, u16_t nsignal)
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{
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int i, n;
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u8_t hopcount;
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u16_t signal;
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/* Find the first unused entry or the used entry with the highest
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hopcount and lowest signal strength. */
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hopcount = 0;
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signal = USHRT_MAX;
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n = 0;
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for(i = 0; i < MAX_NEIGHBORS; ++i) {
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if(rimeaddr_cmp(&neighbors[i].addr, &rimeaddr_null) ||
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rimeaddr_cmp(&neighbors[i].addr, addr)) {
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n = i;
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break;
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}
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if(!rimeaddr_cmp(&neighbors[i].addr, &rimeaddr_null)) {
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if(neighbors[i].hopcount > hopcount) {
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hopcount = neighbors[i].hopcount;
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signal = neighbors[i].signal;
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n = i;
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} else if(neighbors[i].hopcount == hopcount) {
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if(neighbors[i].signal < signal) {
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hopcount = neighbors[i].hopcount;
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signal = neighbors[i].signal;
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n = i;
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/* printf("%d: found worst neighbor %d with hopcount %d, signal %d\n",
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node_id, neighbors[n].nodeid, hopcount, signal);*/
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}
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}
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}
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}
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/* printf("%d: adding neighbor %d with hopcount %d, signal %d at %d\n",
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node_id, neighbors[n].nodeid, hopcount, signal, n);*/
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neighbors[n].time = 0;
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rimeaddr_copy(&neighbors[i].addr, addr);
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neighbors[n].hopcount = nhopcount;
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neighbors[n].signal = nsignal;
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}
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/*---------------------------------------------------------------------------*/
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void
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neighbor_remove(rimeaddr_t *addr)
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{
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int i;
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for(i = 0; i < MAX_NEIGHBORS; ++i) {
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if(rimeaddr_cmp(&neighbors[i].addr, addr)) {
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printf("%d: removing %d @ %d\n", rimeaddr_node_addr.u16, addr->u16, i);
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rimeaddr_copy(&neighbors[i].addr, &rimeaddr_null);
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neighbors[i].hopcount = HOPCOUNT_MAX;
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return;
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}
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}
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}
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/*---------------------------------------------------------------------------*/
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struct neighbor *
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neighbor_best(void)
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{
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int i, found;
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int lowest, best;
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u8_t hopcount;
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u16_t signal;
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hopcount = HOPCOUNT_MAX;
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lowest = 0;
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found = 0;
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/* printf("%d: ", node_id);*/
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/* Find the lowest hopcount. */
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for(i = 0; i < MAX_NEIGHBORS; ++i) {
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/* printf("%d:%d ", neighbors[i].nodeid, neighbors[i].hopcount);*/
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if(!rimeaddr_cmp(&neighbors[i].addr, &rimeaddr_null) &&
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hopcount > neighbors[i].hopcount) {
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hopcount = neighbors[i].hopcount;
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lowest = i;
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found = 1;
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}
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}
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/* printf("\n");*/
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/* Find the neighbor with highest signal strength of the ones that
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have the lowest hopcount. */
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if(found) {
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signal = 0;
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best = lowest;
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for(i = 0; i < MAX_NEIGHBORS; ++i) {
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if(!rimeaddr_cmp(&neighbors[i].addr, &rimeaddr_null) &&
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hopcount == neighbors[i].hopcount &&
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neighbors[i].signal > signal) {
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signal = neighbors[i].signal;
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best = i;
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}
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}
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return &neighbors[best];
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}
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return NULL;
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}
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/*---------------------------------------------------------------------------*/
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