Very aggressive script to handle stuck network interfaces on a raspberry pi

keep_wifi_up.sh

#!/bin/sh

ROUTER_IP=192.168.1.1

COUNTER=/tmp/networkisdown

MAXCALLS_REBOOT=6

WIFI_INTERFACES="wlan0 wlan1"

# Try the router, if it fails (ie. you are on an unknown network) try an external ip.
WIFI_TEST_CMD(){
    (ping -c 2 -w 2 $ROUTER_IP || ping -c 2 1.1.1.1 || ping -c 2 8.8.8.8) > /dev/null 2>&1
}
TINC_TEST_CMD(){
    (ping -c 2 10.9.0.3 || ping -c 2 10.9.0.1 || ping -c 2 10.9.0.2) > /dev/null 2>&1
}


error(){ >&2 echo "$@"; }

if [ ! -e "/run/systemd/system" ]; then
    error "This script assumes systemd is the init system."
    error "You can probably adapt it if it is not."
    exit 99
fi


# Check if wifi is up and try to reset, eventually reboot the machine.

if ! WIFI_TEST_CMD ; then

    if [ -e "$COUNTER" ] && [ "$(stat -c %s $COUNTER)" -ge "$MAXCALLS_REBOOT" ]; then
        echo "Network down, rebooting."
        echo "$(date)"
        systemctl reboot
    else
        printf . >> $COUNTER
        systemctl daemon-reload
        systemctl restart dhcpcd
    fi

else

    # Network is reachable, reset counter.
    if [ -e "$COUNTER" ]; then
        rm $COUNTER
    fi

    # Check wifi interfaces:
    for INTERFACE in $WIFI_INTERFACES; do
        if ! iw dev "$INTERFACE" link | grep -q Connected; then
            ip link set "$INTERFACE" down
            sleep 5
            ip link set "$INTERFACE" up
        fi
    done

    # If wifi works, check if tinc is working, and restart it if not.
    if ! TINC_TEST_CMD ; then
        systemctl restart 'tinc*'
    fi
    
fi