EdgeRouter X VTI IPSec VPN and Dynamic IP Address

This is a used on an EdgeRouter X with three WAN connections. Only one is ever active at a time. They are all DHCP. The BASH script cycles between the three WAN connections until a stable VPN is made.

Script below:

#!/bin/bash
# /config/scripts/VTI-update.sh

source /opt/vyatta/etc/functions/script-template
run=/opt/vyatta/bin/vyatta-op-cmd-wrapper

inf="eth1"
if [[ -e /config/scripts/.VTI-inf ]]
then
  inf="$(cat /config/scripts/.VTI-inf)"
fi

cnt="0"
if [[ -e /config/scripts/.VTI-cnt ]]
then
  cnt="$(cat /config/scripts/.VTI-cnt)"
fi

current_ip="$(run show interfaces ethernet "$inf" | grep "global "$inf"" | sed 's/  inet //g' | cut -d "/" -f1 | tr -d '\n' | sed 's/^ *//')"
configured_ip="$(cat /opt/vyatta/config/active/vpn/ipsec/site-to-site/peer/123.123.123.123/local-address/node.val)"

if [[ -n $current_ip && $configured_ip != $current_ip ]]
then
  echo $(date +"%Y-%m-%d %T") "Old IP: '$configured_ip'."
  echo $(date +"%Y-%m-%d %T") "New IP: '$current_ip'."
  configure
  set vpn ipsec site-to-site peer 123.123.123.123 local-address ${current_ip}
  commit
  save
elif [[ -n $current_ip ]]
then
  # ping the remote vti
  /bin/ping -n -c 1 -W 1 -w1 10.6.101.1 >/dev/null 2>&1
  if [ $? -ne 0 ]
  then
    if [[ $cnt -le 1 ]]
    then
      echo $(date +"%Y-%m-%d %T") "Restarting VPN."
      run restart vpn
      cnt=$[$cnt +1]
      echo "$cnt" > /config/scripts/.VTI-cnt
    else
      case $inf in
        "eth1")
          echo "eth2" > /config/scripts/.VTI-inf
          echo "0" > /config/scripts/.VTI-cnt
          ;;
        "eth2")
          echo "eth0" > /config/scripts/.VTI-inf
          echo "0" > /config/scripts/.VTI-cnt
          ;;
        *)
          echo "eth1" > /config/scripts/.VTI-inf
          echo "0" > /config/scripts/.VTI-cnt
          ;;
      esac
    fi
  else
    echo "0" > /config/scripts/.VTI-cnt
  fi
fi
exit 0