vpncheck.sh

#!/bin/ash
export PATH=/usr/bin:/usr/sbin:/bin:/sbin
export LOCKFILE=/tmp/vpncheck.pid
export LOGFILE=/var/log/vpncheck.log

checktun() {
  ifconfig | grep -q tun && return 1
  return 0
}

checkopenvpn() {
  pgrep openvpn && return 1
  return 0
}

if [[ -f /tmp/vpncheck.pid ]]; then
  echo "[$(date +'%Y-%m-%d %H:%M:%S')] $LOCKFILE is present. Exiting." | tee -a $LOGFILE
  exit
fi

echo $$ > $LOCKFILE

while [[ 1 ]]; do
  checktun
  if [[ $? == 0 ]]; then
    echo "[$(date +'%Y-%m-%d %H:%M:%S')] Tunnel is down." | tee -a $LOGFILE
    checkopenvpn
    if [[ $? == 0 ]]; then
      echo "[$(date +'%Y-%m-%d %H:%M:%S')] OpenVPN not running, attempting reconnection." | tee -a $LOGFILE
      openvpn --cd /etc/openvpn --config /etc/openvpn/aws-ida-gds.ovpn &
    else
      echo "[$(date +'%Y-%m-%d %H:%M:%S')] OpenVPN running." | tee -a $LOGFILE
    fi
    sleep 10
  else
    echo "[$(date +'%Y-%m-%d %H:%M:%S')] Tunnel is up." | tee -a $LOGFILE
    break
  fi

  sleep 5
done

rm $LOCKFILE

# truncate log file to last 50 lines
tail -n 50 $LOGFILE > $LOGFILE.tmp && cat $LOGFILE.tmp > $LOGFILE && rm $LOGFILE.tmp