contiki/core/net/neighbor-info.c

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/*
* Copyright (c) 2010, 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-info.c,v 1.18 2010/12/15 14:35:07 nvt-se Exp $
*/
/**
* \file
* A generic module for management of neighbor information.
*
* \author Nicolas Tsiftes <nvt@sics.se>
*/
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#include "net/neighbor-info.h"
#include "net/neighbor-attr.h"
#define DEBUG DEBUG_NONE
#include "net/uip-debug.h"
#define ETX_LIMIT 15
#define ETX_SCALE 100
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#define ETX_ALPHA 90
#define ETX_NOACK_PENALTY ETX_LIMIT
/*---------------------------------------------------------------------------*/
NEIGHBOR_ATTRIBUTE(link_metric_t, etx, NULL);
static neighbor_info_subscriber_t subscriber_callback;
/*---------------------------------------------------------------------------*/
static void
update_metric(const rimeaddr_t *dest, int packet_metric)
{
link_metric_t *metricp;
link_metric_t recorded_metric, new_metric;
metricp = (link_metric_t *)neighbor_attr_get_data(&etx, dest);
packet_metric = NEIGHBOR_INFO_ETX2FIX(packet_metric);
if(metricp == NULL || *metricp == 0) {
recorded_metric = NEIGHBOR_INFO_ETX2FIX(ETX_LIMIT);
new_metric = packet_metric;
} else {
recorded_metric = *metricp;
/* Update the EWMA of the ETX for the neighbor. */
new_metric = ((uint16_t)recorded_metric * ETX_ALPHA +
(uint16_t)packet_metric * (ETX_SCALE - ETX_ALPHA)) / ETX_SCALE;
}
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PRINTF("neighbor-info: ETX changed from %d to %d (packet ETX = %d) %d\n",
NEIGHBOR_INFO_FIX2ETX(recorded_metric),
NEIGHBOR_INFO_FIX2ETX(new_metric),
NEIGHBOR_INFO_FIX2ETX(packet_metric),
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dest->u8[7]);
if(neighbor_attr_has_neighbor(dest)) {
neighbor_attr_set_data(&etx, dest, &new_metric);
if(new_metric != recorded_metric && subscriber_callback != NULL) {
subscriber_callback(dest, 1, new_metric);
}
}
}
/*---------------------------------------------------------------------------*/
static void
add_neighbor(const rimeaddr_t *addr)
{
switch(neighbor_attr_add_neighbor(addr)) {
case -1:
PRINTF("neighbor-info: failed to add a node.\n");
break;
case 0:
PRINTF("neighbor-info: The neighbor is already known\n");
break;
default:
break;
}
}
/*---------------------------------------------------------------------------*/
void
neighbor_info_packet_sent(int status, int numtx)
{
const rimeaddr_t *dest;
link_metric_t packet_metric;
dest = packetbuf_addr(PACKETBUF_ADDR_RECEIVER);
if(rimeaddr_cmp(dest, &rimeaddr_null)) {
return;
}
packet_metric = numtx;
PRINTF("neighbor-info: packet sent to %d.%d, status=%d, metric=%u\n",
dest->u8[sizeof(*dest) - 2], dest->u8[sizeof(*dest) - 1],
status, (unsigned)packet_metric);
switch(status) {
case MAC_TX_OK:
add_neighbor(dest);
break;
case MAC_TX_NOACK:
packet_metric = ETX_NOACK_PENALTY;
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break;
default:
/* Do not penalize the ETX when collisions or transmission
errors occur. */
return;
}
update_metric(dest, packet_metric);
}
/*---------------------------------------------------------------------------*/
void
neighbor_info_packet_received(void)
{
const rimeaddr_t *src;
src = packetbuf_addr(PACKETBUF_ADDR_SENDER);
if(rimeaddr_cmp(src, &rimeaddr_null)) {
return;
}
PRINTF("neighbor-info: packet received from %d.%d\n",
src->u8[sizeof(*src) - 2], src->u8[sizeof(*src) - 1]);
add_neighbor(src);
}
/*---------------------------------------------------------------------------*/
int
neighbor_info_subscribe(neighbor_info_subscriber_t s)
{
if(subscriber_callback == NULL) {
neighbor_attr_register(&etx);
subscriber_callback = s;
return 1;
}
return 0;
}
/*---------------------------------------------------------------------------*/
link_metric_t
neighbor_info_get_metric(const rimeaddr_t *addr)
{
link_metric_t *metricp;
metricp = (link_metric_t *)neighbor_attr_get_data(&etx, addr);
return metricp == NULL ? ETX_LIMIT : *metricp;
}
/*---------------------------------------------------------------------------*/