#! /bin/sh
# Simple Script to start and monitor an  OpenVpn Connection
# Feel free to Fork, Edit, Optimize....
# Usefull command to check the VPN connection
# watch -n 10 'traceroute -m 2 www.yahoo.com'
# watch -n 10 'dig +short myip.opendns.com @resolver2.opendns.com'

#SLEEPTIME is the amount to wait between check
SLEEPTIME=5m
PUBLICIPTOHIDE="176.141."

# Helper to direcly log message to console and log file
function log()
 {
  #TODO : see if we can optimize this function
  LOGDIRECTORY=/var/log/openvpn/client
  LOGFILE="/var/log/openvpn/client-$(date +%Y-%m).log"
  STRLINE="$(date "+%a %b %d %H:%M:%S %Y ") $1"
  echo $STRLINE & echo $STRLINE >> $LOGFILE
  chmod 666 $LOGFILE
 }

# Function that start the OpenVpn Connection
function startconn()
{
 STR="OPENVPN CONNECTION Started at $(date +%Y-%m-%d-%k-%M-%S)"
 log "$STR"
 #openvpn --config /etc/openvpn/client/client.conf --daemon --ca /etc/openvpn/client/ca.crt --tls-auth /etc/openvpn/client/Wdc.key --auth-user-pass /etc/openvpn/client
 openvpn --daemon --config /etc/openvpn/client/client.conf --ca /etc/openvpn/client/ca.crt --tls-auth /etc/openvpn/client/Wdc.key --auth-user-pass /etc/openvpn/client/auth.txt --script-security 2 --route-up "/bin/sh /etc/openvpn/vpn-up.sh" --down "/bin/sh /etc/openvpn/vpn-down.sh" --verb 3  --log-append $LOGFILE --mute 100000
}

#function that stop all the OpenVpn Connection
function stopconn()
{
 killall -w openvpn
 STR="OPENVPN CONNECTION Closed  at $(date +%Y-%m-%d-%k-%M-%S)"
 log "$STR"
}

#Function for trapping the end signal
function trap_finish {
 log "Exit signal received..."
 stopconn
}
trap trap_finish EXIT


#Check if  a string $2 is   a substring of another string $1
#Return 1 if $2 is found in $1, 0 if not found
function is_substring()
{
my_string=$1
substring=$2
STRFOUND=0
if [ "${my_string/$substring}" = "$my_string" ] ; then
  #echo "DEBUG-[${substring}] is not in [${my_string}]"
  STRFOUND=0
else
  #echo "DEBUG-[${substring}] was found in [${my_string}]"
  STRFOUND=1
fi

#echo "DEBUG-STRFOUND=$STRFOUND"
return $STRFOUND
}

#Function that test if the VPN connection is UP and if the Public IP is hidden
#Return values :
# 0  public ip is hidden
# 1  public ip is not hidden
# 2  not enable to get external ip
function checkvpnok()
{
  RETURNVALUE=2
  EXTERNALIP=$(dig +short myip.opendns.com @resolver1.opendns.com)
  #log "IPTOHIDE=[$PUBLICIPTOHIDE] CURRENT PUBLIC=[$EXTERNALIP]"
  if [ -z $EXTERNALIP ]
  then
    RETURNVALUE=2
    log "CHECKVPNOK : ERROR  (not able to get external IP )"
    #return $RETURNVALUE
  fi

  is_substring $EXTERNALIP $PUBLICIPTOHIDE
  IPFOUND=$?

  #echo "DEBUG-IPFOUND=[$IPFOUND]"

  if [ $IPFOUND == "1" ]
  then
   #echo "KO : Public IP is not hidden"
   log "CHECKVPNOK : KO_PUBLIC_IP_NOT_HIDDEN (EXTERNALIP=[$EXTERNALIP] PUBLICIPTOHIDE=[$PUBLICIPTOHIDE])"
   RETURNVALUE=1
  else
   #echo "OK : Public IP is hidden"
   log "CHECKVPNOK : OK_PUBLIC_IP_HIDDEN (EXTERNALIP=[$EXTERNALIP] PUBLICIPTOHIDE=[$PUBLICIPTOHIDE])"
   RETURNVALUE=0
  fi

  #echo "DEBUG-RETURNVALUE=$RETURNVALUE"
  return $RETURNVALUE
}


#MAIN PROGRAM
echo "Simple script that start and monitor an OpenVpn connection endlessly"
echo "Hit [CTRL+C] to stop !"
killall -w openvpn

while true
do
 checkvpnok
 #if public IP is not hidden or if there is a problem on the connection, restarting the OpenVpn Client
 PUBLICIPHIDDEN=$?
 if [ $PUBLICIPHIDDEN == "1" ]
 then
  startconn
 fi
 #Waiting for sometime
 sleep $SLEEPTIME
done

#Stopping connections before exiting
stopconn

exit 0