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Added link-stats module to keep strack of link statistics and their freshness

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Simon Duquennoy 2015-11-29 21:31:59 +01:00 committed by Simon Duquennoy
parent 4e9b027141
commit 2fa239ee8d
4 changed files with 286 additions and 0 deletions
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4
core/net/ipv6/sicslowpan.c
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@ -62,6 +62,7 @@
#include "contiki.h"
#include "dev/watchdog.h"
#include "net/link-stats.h"
#include "net/ip/tcpip.h"
#include "net/ip/uip.h"
#include "net/ipv6/uip-ds6.h"
@ -1516,6 +1517,9 @@ input(void)
uint8_t first_fragment = 0, last_fragment = 0;
#endif /*SICSLOWPAN_CONF_FRAG*/
/* Update link statistics */
link_stats_input_callback(packetbuf_addr(PACKETBUF_ADDR_SENDER));
/* init */
uncomp_hdr_len = 0;
packetbuf_hdr_len = 0;

5
core/net/ipv6/uip-ds6-nbr.c
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@ -47,6 +47,7 @@
#include <stdlib.h>
#include <stddef.h>
#include "lib/list.h"
#include "net/link-stats.h"
#include "net/linkaddr.h"
#include "net/packetbuf.h"
#include "net/ipv6/uip-ds6-nbr.h"
@ -74,6 +75,7 @@ NBR_TABLE_GLOBAL(uip_ds6_nbr_t, ds6_neighbors);
void
uip_ds6_neighbors_init(void)
{
link_stats_init();
nbr_table_register(ds6_neighbors, (nbr_table_callback *)uip_ds6_nbr_rm);
}
/*---------------------------------------------------------------------------*/
@ -204,6 +206,9 @@ uip_ds6_link_neighbor_callback(int status, int numtx)
return;
}
/* Update neighbor link statistics */
link_stats_packet_sent(dest, status, numtx);
/* Call upper-layer callback (e.g. RPL) */
LINK_NEIGHBOR_CALLBACK(dest, status, numtx);
#if UIP_DS6_LL_NUD

212
core/net/link-stats.c Normal file
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@ -0,0 +1,212 @@
/*
* Copyright (c) 2015, SICS Swedish ICT.
* 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.
*
*
* Authors: Simon Duquennoy <simonduq@sics.se>
*/
#include "contiki.h"
#include "sys/clock.h"
#include "net/packetbuf.h"
#include "net/nbr-table.h"
#include "net/link-stats.h"
#include <stdio.h>
#define DEBUG 0
#if DEBUG
#define PRINTF(...) printf(__VA_ARGS__)
#else
#define PRINTF(...)
#endif
/* Half time for the freshness counter, in minutes */
#define FRESHNESS_HALF_LIFE 20
/* Statistics are fresh if the freshness counter is FRESHNESS_TARGET or more */
#define FRESHNESS_TARGET 4
/* Maximum value for the freshness counter */
#define FRESHNESS_MAX 16
/* Statistics with no update in FRESHNESS_EXPIRATION_TIMEOUT is not fresh */
#define FRESHNESS_EXPIRATION_TIME (10 * 60 * CLOCK_SECOND)
/* EWMA (exponential moving average) used to maintain statistics over time */
#define EWMA_SCALE 100
#define EWMA_ALPHA 10
#define EWMA_BOOTSTRAP_ALPHA 30
/* ETX fixed point divisor. 128 is the value used by RPL (RFC 6551 and RFC 6719) */
#define ETX_DIVISOR LINK_STATS_ETX_DIVISOR
/* Number of Tx used to update the ETX EWMA in case of no-ACK */
#define ETX_NOACK_PENALTY 16
/* Initial ETX value */
#define ETX_INIT 2
/* Per-neighbor link statistics table */
NBR_TABLE(struct link_stats, link_stats);
/* Called every FRESHNESS_HALF_LIFE minutes */
struct ctimer periodic_timer;
/* Used to initialize ETX before any transmission occurs. In order to
* infer the initial ETX from the RSSI of previously received packets, use: */
/* #define LINK_STATS_CONF_INIT_ETX(stats) guess_etx_from_rssi(stats) */
#ifdef LINK_STATS_CONF_INIT_ETX
#define LINK_STATS_INIT_ETX(stats) LINK_STATS_CONF_INIT_ETX(stats)
#else /* LINK_STATS_INIT_ETX */
#define LINK_STATS_INIT_ETX(stats) (ETX_INIT * ETX_DIVISOR)
#endif /* LINK_STATS_INIT_ETX */
/*---------------------------------------------------------------------------*/
/* Returns the neighbor's link stats */
const struct link_stats *
link_stats_from_lladdr(const linkaddr_t *lladdr)
{
return nbr_table_get_from_lladdr(link_stats, lladdr);
}
/*---------------------------------------------------------------------------*/
/* Are the statistics fresh? */
int
link_stats_is_fresh(const struct link_stats *stats)
{
return (stats != NULL)
&& clock_time() - stats->last_tx_time < FRESHNESS_EXPIRATION_TIME
&& stats->freshness >= FRESHNESS_TARGET;
}
/*---------------------------------------------------------------------------*/
uint16_t
guess_etx_from_rssi(const struct link_stats *stats)
{
if(stats != NULL) {
if(stats->rssi == 0) {
return ETX_INIT * ETX_DIVISOR;
} else {
/* A rough estimate of PRR from RSSI, as a linear function where:
* RSSI >= -60 results in PRR of 1
* RSSI <= -90 results in PRR of 0
* prr = (bounded_rssi - RSSI_LOW) / (RSSI_DIFF)
* etx = ETX_DIVOSOR / ((bounded_rssi - RSSI_LOW) / RSSI_DIFF)
* etx = (RSSI_DIFF * ETX_DIVOSOR) / (bounded_rssi - RSSI_LOW)
* */
#define ETX_INIT_MAX 3
#define RSSI_HIGH -60
#define RSSI_LOW -90
#define RSSI_DIFF (RSSI_HIGH - RSSI_LOW)
uint16_t etx;
int16_t bounded_rssi = stats->rssi;
bounded_rssi = MIN(bounded_rssi, RSSI_HIGH);
bounded_rssi = MAX(bounded_rssi, RSSI_LOW + 1);
etx = RSSI_DIFF * ETX_DIVISOR / (bounded_rssi - RSSI_LOW);
return MIN(etx, ETX_INIT_MAX * ETX_DIVISOR);
}
}
return 0xffff;
}
/*---------------------------------------------------------------------------*/
/* Packet sent callback. Updates stats for transmissions to lladdr */
void
link_stats_packet_sent(const linkaddr_t *lladdr, int status, int numtx)
{
struct link_stats *stats;
uint16_t packet_etx;
uint8_t ewma_alpha;
if(status != MAC_TX_OK && status != MAC_TX_NOACK) {
/* Do not penalize the ETX when collisions or transmission errors occur. */
return;
}
stats = nbr_table_get_from_lladdr(link_stats, lladdr);
if(stats == NULL) {
/* Add the neighbor */
stats = nbr_table_add_lladdr(link_stats, lladdr);
if(stats != NULL) {
stats->etx = LINK_STATS_INIT_ETX(stats);
} else {
return; /* No space left, return */
}
}
/* Update last timestamp and freshness */
stats->last_tx_time = clock_time();
stats->freshness = MIN(stats->freshness + numtx, FRESHNESS_MAX);
/* ETX used for this update */
packet_etx = ((status == MAC_TX_NOACK) ? ETX_NOACK_PENALTY : numtx) * ETX_DIVISOR;
/* ETX alpha used for this update */
ewma_alpha = link_stats_is_fresh(stats) ? EWMA_ALPHA : EWMA_BOOTSTRAP_ALPHA;
/* Compute EWMA and update ETX */
stats->etx = ((uint32_t)stats->etx * (EWMA_SCALE - ewma_alpha) +
(uint32_t)packet_etx * ewma_alpha) / EWMA_SCALE;
}
/*---------------------------------------------------------------------------*/
/* Packet input callback. Updates statistics for receptions on a given link */
void
link_stats_input_callback(const linkaddr_t *lladdr)
{
struct link_stats *stats;
int16_t packet_rssi = packetbuf_attr(PACKETBUF_ATTR_RSSI);
stats = nbr_table_get_from_lladdr(link_stats, lladdr);
if(stats == NULL) {
/* Add the neighbor */
stats = nbr_table_add_lladdr(link_stats, lladdr);
if(stats != NULL) {
/* Initialize */
stats->rssi = packet_rssi;
stats->etx = LINK_STATS_INIT_ETX(stats);
} else {
return; /* No space left, return */
}
}
/* Update RSSI EWMA */
stats->rssi = ((int32_t)stats->rssi * (EWMA_SCALE - EWMA_ALPHA) +
(int32_t)packet_rssi * EWMA_ALPHA) / EWMA_SCALE;
}
/*---------------------------------------------------------------------------*/
/* Periodic timer called every FRESHNESS_HALF_LIFE minutes */
static void
periodic(void *ptr)
{
/* Age (by halving) freshness counter of all neighbors */
struct link_stats *stats;
ctimer_reset(&periodic_timer);
for(stats = nbr_table_head(link_stats); stats != NULL; stats = nbr_table_next(link_stats, stats)) {
stats->freshness >>= 1;
}
}
/*---------------------------------------------------------------------------*/
/* Initializes link-stats module */
void
link_stats_init(void)
{
nbr_table_register(link_stats, NULL);
ctimer_set(&periodic_timer, 60 * CLOCK_SECOND * FRESHNESS_HALF_LIFE,
periodic, NULL);
}

65
core/net/link-stats.h Normal file
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@ -0,0 +1,65 @@
/*
* Copyright (c) 2015, SICS Swedish ICT.
* 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.
*
*
* Authors: Simon Duquennoy <simonduq@sics.se>
*/
#ifndef LINK_STATS_H_
#define LINK_STATS_H_
#include "core/net/linkaddr.h"
/* ETX fixed point divisor. 128 is the value used by RPL (RFC 6551 and RFC 6719) */
#ifdef LINK_STATS_CONF_ETX_DIVISOR
#define LINK_STATS_ETX_DIVISOR LINK_STATS_CONF_ETX_DIVISOR
#else /* LINK_STATS_CONF_ETX_DIVISOR */
#define LINK_STATS_ETX_DIVISOR 128
#endif /* LINK_STATS_CONF_ETX_DIVISOR */
/* All statistics of a given link */
struct link_stats {
uint16_t etx; /* ETX using ETX_DIVISOR as fixed point divisor */
int16_t rssi; /* RSSI (received signal strength) */
uint8_t freshness; /* Freshness of the statistics */
clock_time_t last_tx_time; /* Last Tx timestamp */
};
/* Returns the neighbor's link statistics */
const struct link_stats *link_stats_from_lladdr(const linkaddr_t *lladdr);
/* Are the statistics fresh? */
int link_stats_is_fresh(const struct link_stats *stats);
/* Initializes link-stats module */
void link_stats_init(void);
/* Packet sent callback. Updates statistics for transmissions on a given link */
void link_stats_packet_sent(const linkaddr_t *lladdr, int status, int numtx);
/* Packet input callback. Updates statistics for receptions on a given link */
void link_stats_input_callback(const linkaddr_t *lladdr);
#endif /* LINK_STATS_H_ */