[OpenWRT] Auto-reboot bad ISP modems on PPP down (Broadcom)

adsl.sh

#!/bin/sh

#Add this file to /root
#For interactive adjustments and keyboard input, install screen "opkg update && opkg install screen"
#and add to rc.local before exit 0: "screen -d -m sh -c "sh /root/adsl.sh" &"
#Enable telnet/port-23 in modem settings, usually open by most bad ISPs
#Replace <> fields with your settings


while :
do
sleep 120 #Increase if your modem takes more than 2 minutes to provide internet connectivity from restart.
if [ "$(ping -q -c5 8.8.8.8 &>/dev/null && echo 0 || echo 1)" = "1" ]; then #Add -I <your wan> after -q for multi-wan setup
        echo "Restarting modem"
        (
        sleep 2
        echo '<username>'
        sleep 1
        echo '<password>'
        sleep 2
        echo 'sh'
        sleep 1
        echo 'reboot'
        sleep 1
        ) | nc <your modem IP> 23 &
        sleep 15
        killall nc
fi
done