Detecting network dropout on orange pi - bash - linux

Question

Im writing a bash script that detects when connection to the internet has dropped and attempts to reconnect as well as displaying status on leds.
Im using the netcat command to connect to google on port 80 to determine if network connection is live
This all works fine when internet is connected, however, when powering off my router (simulating dropout) the netcast command takes aroud 30 seconds to timeout!
Application is for a WiFi radio,
#!/bin/bash
sig_state=0
echo "Network Watchdog ON"
echo "0" > /sys/class/gpio/export
echo "out" > /sys/class/gpio/gpio0/direction
function sig_led_high
{
echo "0" > /sys/class/gpio/gpio0/value
sig_state=1
}
function sig_led_low
{
echo "1" > /sys/class/gpio/gpio0/value
sig_state=0
}
sig_led_low
while true ; do
echo "Testing nwrk..."
if nc -z -w 1 www.google.co.uk 80 > /dev/null 2>&1; then
echo "Network OK. (nwd)"
if ((sig_state)); then
sig_led_low
fi
else
if !((sig_state)); then
sig_led_high
fi
echo "Network connection down! Attempting reconnection."
ifup --force wlan0 > /dev/null 2>&1
if nc -zw1 www.google.co.uk 80 > /dev/null 2>&1; then
mpc play
fi
fi
sleep 1
done