net/ddns-scripts/samples/getlocalip_sample.sh

   1 #!/bin/sh
   2 #
   3 # sample script for detecting local IP
   4 # 2014-2015 Christian Schoenebeck <christian dot schoenebeck at gmail dot com>
   5 #
   6 # activated inside /etc/config/ddns by setting
   7 #
   8 # option ip_source      'script'
   9 # option ip_script      '/usr/lib/ddns/getlocalip_sample.sh -6' !!! parameters ALLOWED
  10 #
  11 # the script is executed (not parsed) inside get_local_ip() function
  12 # of /usr/lib/ddns/dynamic_dns_functions.sh
  13 #
  14 # useful when this box is the only DDNS client in the network
  15 # IP adresses of "internal" boxes could be detected with this script
  16 # so no need to install ddns client on every "internal" box
  17 # On IPv6 every internal box normally has it's own external IP
  18 #
  19 # This script should
  20 #       - return the IP address via stdout      echo -n "...."  !!! without line feed
  21 #       - report errors via stderr              echo "...." >&2
  22 #       - return an error code ('0' for success)        exit 123
  23
  24 case $1 in
  25         -4)     echo -n "8.8.8.8"               # never append linefeed or simular
  26                 exit 0
  27                 ;;                              # IP's of Googles public DNS
  28         -6)     echo -n "2001:4860:4860::8888"
  29                 exit 0
  30                 ;;
  31         *)      echo "$0 - Invalid or missing parameter" >&2
  32                 exit 1
  33 esac
  34 echo "Should never come here" >&2
  35 exit 2