#!/bin/sh
 
# Default GW
GW1=97.229.191.1
GW2=88.34.0.1
 
# IP for check
dst1=8.8.8.8
dst2=8.8.4.4
dst3=4.2.2.1
 
#dst1=1.1.1.1
#dst2=2.2.2.2
#dst3=3.3.3.3
 
# VAR
ping1=0
ping2=0
ping3=0
 
# Script start here
 
ping1=$(ping -c 3 -s 8 -o -t 2 $dst1 | awk 'BEGIN{s=""} $2~/bytes/{s=s "X"} END{print s}')
ping2=$(ping -c 3 -s 8 -o -t 2 $dst2 | awk 'BEGIN{s=""} $2~/bytes/{s=s "X"} END{print s}')
ping3=$(ping -c 3 -s 8 -o -t 2 $dst3 | awk 'BEGIN{s=""} $2~/bytes/{s=s "X"} END{print s}')
 
all=$ping1$ping2$ping3
 
if [ "$all" == "" ]; then
    if [ -f /tmp/second.gw ]; then
        echo "Already switched to secondary"
    else
        /sbin/route delete default
        /sbin/route add default $GW2
        /sbin/route add -host $dst1 $GW1
        /sbin/route add -host $dst2 $GW1
        /sbin/route add -host $dst3 $GW1
        /sbin/pfctl -F all -f /etc/pf.conf-rtk
        touch /tmp/second.gw
        echo "Primary failed. Switching to secondary" | mail -s "Primary inet channel failed" root
    fi
else
    if [ -f /tmp/second.gw ]; then
        /sbin/route delete default
        /sbin/route add default $GW1
        /sbin/route del -host $dst1 $GW1
        /sbin/route del -host $dst2 $GW1
        /sbin/route del -host $dst3 $GW1
        /sbin/pfctl -F all -f /etc/pf.conf
        echo "Primary restored. Switching back" | mail -s "Primary inet channel restored" root
        rm /tmp/second.gw
    fi
fi