openvpn/contrib/pull-resolv-conf/client.down

   1 #!/bin/bash
   2
   3 # Copyright (c) 2005 by OpenVPN Solutions LLC
   4 # Licensed under the GPL version 2
   5
   6 # First version by Jesse Adelman
   7 # someone at boldandbusted dink com
   8 # http://www.boldandbusted.com/
   9
  10 # PURPOSE: This script automatically removes the /etc/resolv.conf entries previously
  11 # set by the companion script "client.up".
  12
  13 # INSTALL NOTES:
  14 # Place this in /etc/openvpn/client.down
  15 # Then, add the following to your /etc/openvpn/<clientconfig>.conf:
  16 #   client
  17 #   pull dhcp-options
  18 #   up /etc/openvpn/client.up
  19 #   down /etc/openvpn/client.down
  20 # Next, "chmod a+x /etc/openvpn/client.down"
  21
  22 # USAGE NOTES:
  23 # Note that this script is best served with the companion "client.up"
  24 # script.
  25
  26 # Only tested on Gentoo Linux 2005.0 with OpenVPN 2.0
  27 # It should work with any GNU/Linux with /etc/resolv.conf
  28
  29 # This runs with the context of the OpenVPN UID/GID
  30 # at the time of execution. This generally means that
  31 # the client "up" script will run fine, but the "down" script
  32 # will require the use of the OpenVPN "down-root" plugin
  33 # which is in the plugins/ directory of the OpenVPN source tree
  34
  35 # A horrid work around, from a security perspective,
  36 # is to run OpenVPN as root. THIS IS NOT RECOMMENDED. You have
  37 # been WARNED.
  38
  39 # init variables
  40
  41 i=1
  42 j=1
  43 unset fopt
  44 unset dns
  45 unset opt
  46
  47 # Convert ENVs to an array
  48
  49 while fopt=foreign_option_$i; [ -n "${!fopt}" ]; do
  50 {
  51         opt[i-1]=${!fopt}
  52         case ${opt[i-1]} in
  53                 *DOMAIN* ) domain=`echo ${opt[i-1]} | \
  54                                 sed -e 's/dhcp-option DOMAIN //g'` ;;
  55                 *DNS*    ) dns[j-1]=`echo ${opt[i-1]} | \
  56                                 sed -e 's/dhcp-option DNS //g'`
  57                                let j++ ;;
  58         esac
  59         let i++
  60 }
  61 done
  62
  63 # Now, do the work
  64
  65 if [ -n "${dns[*]}" ]; then
  66         for i in "${dns[@]}"; do
  67                 sed -i -e "/nameserver ${i}/D" /etc/resolv.conf || die
  68         done
  69 fi
  70
  71 if [ -n "${domain}" ]; then
  72         sed -i -e "/search ${domain}/D" /etc/resolv.conf || die
  73 fi
  74
  75 # all done...
  76 exit 0