#!/bin/sh

#set -x
#trap read debug

TIMEOUT=60
TIMEOUT_DHCP=120
INTERFACE=ens32
LOG=/root/netcheck.log
SCRIPT_PATH=/root
WIREGUARD_IP="10.7.1.1"
INTERNET_IP1="8.8.8.8"
INTERNET_IP2="4.2.2.2"
CHECK_INTERVAL=5        #how often to perform checks in seconds
#NET_INT=`ip route | awk '/default/ { print $5 }'`    #default gateway interface
NET_INT=ens32
WG_INT=wg0

# exit if another instance of script is already running
        MY_SCRIPT_NAME=`basename "$0"`
        if pidof -o %PPID  -x $MY_SCRIPT_NAME  > /dev/null; then
        echo "`date +%Y-%m-%d" "%H:%M:%S` `hostname | cut -d'.' -f1` netcheck.sh: Watchdog script already running, PID:`pidof -o %PPID  -x $MY_SCRIPT_NAME`,  exiting." >> $LOG 2>&1
        exit 1
        fi

check_ip () {
        if ping -c 1 -W 1 $1 > /dev/null 2>&1
        then return
        else
        return
        fi

}

# 1 check wireguard connectivity
# 2 if good, exit, if not, check internet connection
# 3 if internet connection good, check wireguard service

while true; do

        if ! check_ip $WIREGUARD_IP
                then
                if check_ip $INTERNET_IP1 || check_ip $INTERNET_IP2 # if internet up then check if wireguard is responsive
                then
                        if ! wg | grep handshake  #restart wg if not active
                        then
                                systemctl restart wg-quick@wg0
                                echo "`date +%Y-%m-%d" "%H:%M:%S` `hostname | cut -d'.' -f1` netcheck.sh: Wireguard not connected, restarting" >> $LOG 2>&1
                        fi
                else
                        systemctl stop wg-quick@wg0
                        dhclient -r -lf /var/lib/dhcp/dhclient.leases.$NET_INT -pf /var/run/dhclient.$NET_INT.pid $NET_INT
                        dhclient -v -lf /var/lib/dhcp/dhclient.leases.$NET_INT -pf /var/run/dhclient.$NET_INT.pid $NET_INT
                        echo $?
                        echo "`date +%Y-%m-%d" "%H:%M:%S` `hostname | cut -d'.' -f1` netcheck.sh: DHCP renewed" >> $LOG 2>&1
                        sleep 5
                        systemctl start wg-quick@$WG_INT
                        echo "`date +%Y-%m-%d" "%H:%M:%S` `hostname | cut -d'.' -f1` netcheck.sh: Wireguard restarted" >> $LOG 2>&1
                fi

        fi
sleep $CHECK_INTERVAL
done