sonar

#!/bin/sh
#
# sonar - Displays signal levels from connected Wi-Fi stations
#
# Copyright (C) 2012 Philippe Gauthier <philippe.gauthier@deuxpi.ca>
# Copyright (C) 2012 Mathieu Lutfy <mathieu@bidon.ca>
# Copyright (C) 2012 Alexandre Guedon <alex@twd.su>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
###

# dBm values from AirOS 5.5 linked to color values for signal strength
NOISE="-96" # Noise floor
LOW="-80"
MED="-73"
HIGH="-65"
NOISECOL="\033[0;31m"
LOWCOL="\033[0;33m"
MEDCOL="\033[0;32m"
HIGHCOL="\033[1;32m"
RESET="\033[0m"
BOLD="\033[1m"

# Test if UBNT LEDs are present
LED_PATH=/sys/devices/platform/leds-gpio/leds
if [ -d $LED_PATH ]; then LEDS="1"; echo "LEDs supported"; fi

set_led() {
    # Set light value, usually 0=off, 255=on
    LIGHT=$2
    if [ $LEDS -eq 1 ]; then
        case $1 in
        1)  echo $LIGHT > $LED_PATH/ubnt:red:link1/brightness ;;
        2)  echo $LIGHT > $LED_PATH/ubnt:orange:link2/brightness ;;
        3)  echo $LIGHT > $LED_PATH/ubnt:green:link3/brightness ;;
        4)  echo $LIGHT > $LED_PATH/ubnt:green:link4/brightness ;;
        esac
    fi
}

turn_all_leds_off() {
    for i in 1 2 3 4 
    do 
        set_led $i 0
    done
}
# Cleanup after signal
on_exit() { 
    if [ $LEDS -eq 1 ]; then
    	echo -ne "\nResetting LEDs to off: "
    	turn_all_leds_off
    	echo "Done"
    fi
    exit
}
trap 'on_exit' 1 2 3 15

# Loop to scan for and display signals
while (true); do
    turn_all_leds_off
    for iface in $(iw dev | grep Interface | cut -f2 -d" "); do
        iw $iface station dump \
        | while read line ; do
            if echo $line | grep -q "Station"; then
                mac=$(echo $line | cut -f2 -d" ")
                host=$(grep -si $mac /etc/ethers|cut -f2 -d" ")
            fi
            if echo $line | grep -q "signal:"; then
                signal=$( echo "$line" | sed 's/.*signal:[\ \t]*\([-0-9]*\).*/\1/' )
                # Quick fix for no signal
                if [ $signal -eq 0 ] ; then  signal="-100"; fi 
                # We've seen a signal, so turn at least the RED led on
                COL=$NOISECOL
                set_led 1 255
                if [ $signal -ge $LOW ]
                    then COL=$LOWCOL
                    set_led 2 255
                fi
                if [ $signal -ge $MED ]
                    then COL=$MEDCOL
                    set_led 3 255
                fi
                if [ $signal -ge $HIGH ]
                    then COL=$HIGHCOL
                    set_led 4 255
                fi
                # Hash for unique color from names in ethers
                HOSTCOL="\033[3"$(echo $(( $(echo -n "$host"|md5sum|tr a-f 0-5|cut -f1 -d" "| head -c 10) % 8 )) )"m"
                echo -e "${BOLD}${mac}${RESET} (on ${BOLD}${iface}${RESET}) ${COL}${signal} dBm${RESET} ${HOSTCOL}${host}${RESET}"
            fi
        done
    done
    sleep 1
    echo
done