Modified rfc3442 classes routes script that includes removing old routes

rfc3442-classless-routes

# set classless routes based on the format specified in RFC3442
# e.g.:
#   new_rfc3442_classless_static_routes='24 192 168 10 192 168 1 1 8 10 10 17 66 41'
# specifies the routes:
#   192.168.10.0/24 via 192.168.1.1
#   10.0.0.0/8 via 10.10.17.66.41

RUN="yes"


if [ "$RUN" = "yes" ]; then

  # clean old static routes
  if [ "$reason" = "RENEW" -o "$reason" = "REBIND" -o "$reason" = "EXPIRE" ]
  then
    if [ -n "$old_rfc3442_classless_static_routes" ]
    then
      if [ "$old_rfc3442_classless_static_routes" != "$new_rfc3442_classless_static_routes" ]
      then

        set -- $old_rfc3442_classless_static_routes

        while [ $# -gt 0 ]; do
          net_length=$1
          via_arg=''

          case $net_length in
            32|31|30|29|28|27|26|25)
              net_address="${2}.${3}.${4}.${5}"
              gateway="${6}.${7}.${8}.${9}"
              shift 9
              ;;
            24|23|22|21|20|19|18|17)
              net_address="${2}.${3}.${4}.0"
              gateway="${5}.${6}.${7}.${8}"
              shift 8
              ;;
            16|15|14|13|12|11|10|9)
              net_address="${2}.${3}.0.0"
              gateway="${4}.${5}.${6}.${7}"
              shift 7
              ;;
            8|7|6|5|4|3|2|1)
              net_address="${2}.0.0.0"
              gateway="${3}.${4}.${5}.${6}"
              shift 6
              ;;
            0)  # default route
              net_address="0.0.0.0"
              gateway="${2}.${3}.${4}.${5}"
              shift 5
              ;;
            *)  # error
              return 1
              ;;
          esac

          # take care of link-local routes
          if [ "${gateway}" != '0.0.0.0' ]; then
            via_arg="via ${gateway}"
          fi

          # remove route
          vtysh -c "configure terminal" -c "no ip route ${net_address}/${net_length} ${via_arg} ${interface}" >/dev/null 2>&1
        done
      fi
    fi
  fi

  if [ "$reason" = "BOUND" -o "$reason" = "RENEW" -o "$reason" = "REBOOT" -o "$reason" = "REBIND" ]
  then
    if [ -n "$new_rfc3442_classless_static_routes" ]
    then

      set -- $new_rfc3442_classless_static_routes

      while [ $# -gt 0 ]; do
        net_length=$1
        via_arg=''

        case $net_length in
          32|31|30|29|28|27|26|25)
            net_address="${2}.${3}.${4}.${5}"
            gateway="${6}.${7}.${8}.${9}"
            shift 9
            ;;
          24|23|22|21|20|19|18|17)
            net_address="${2}.${3}.${4}.0"
            gateway="${5}.${6}.${7}.${8}"
            shift 8
            ;;
          16|15|14|13|12|11|10|9)
            net_address="${2}.${3}.0.0"
            gateway="${4}.${5}.${6}.${7}"
            shift 7
            ;;
          8|7|6|5|4|3|2|1)
            net_address="${2}.0.0.0"
            gateway="${3}.${4}.${5}.${6}"
            shift 6
            ;;
          0)  # default route
            net_address="0.0.0.0"
            gateway="${2}.${3}.${4}.${5}"
            shift 5
            ;;
          *)  # error
            return 1
            ;;
        esac

        # take care of link-local routes
        if [ "${gateway}" != '0.0.0.0' ]; then
          via_arg="via ${gateway}"
        fi

        # set route (ip detects host routes automatically)
        vtysh -c "configure terminal" -c "ip route ${net_address}/${net_length} ${via_arg} ${interface}" >/dev/null 2>&1
      done
    fi
  fi
fi