#!/usr/bin/perl
#
# updates /etc/resolv.conf for openvpn (www.openvpn.net)
# this hack (c) 2006 torh@bogus.net
#
# add the following to your client.ovpn file(s):
#
# up /path/to/resolvfix.pl
# down /path/to/resolvfix.pl
#
# (place this file as resolvfix.pl in /path/to)

umask(022);
$ENV{'PATH'}="/bin:/usr/bin";

if($ENV{'script_type'} eq "down") {
  ## quit if we can't find a resolv.conf.ovpnbak file OR if that file
  ## is zero size.
  if(-f "/etc/resolv.conf.ovpnbak" && -s "/etc/resolv.conf.ovpnbak") {
    $move=`mv -f /etc/resolv.conf.ovpnbak /etc/resolv.conf`;
  } 
  exit(0);
}

exit(0) unless(defined($ENV{'foreign_option_1'})); # if no options, just quit

if($ENV{'script_type'} eq "up") {
  ## make a backup of the resolver file
  ##
  $copy=`cp -p /etc/resolv.conf /etc/resolv.conf.ovpnbak 2>/dev/stdout`;
  if($copy) {
    die "Cannot create backup of /etc/resolv.conf: $copy";
    exit(1);
  }
  ## overwrite the original with the pushed search and nameserver
  ## parameters
  open(OUT,">/etc/resolv.conf") || die "Can't write to /etc/resolv.conf: $!";
  foreach $env (keys %ENV) {
    if($env =~ /foreign_option/) {
      if($ENV{$env} =~ /DOMAIN\s+(\S+)/) {
  	print OUT "search $1\n";
      }
      if($ENV{$env} =~ /DNS\s+(\d+\.\d+\.\d+\.\d+)/) {
  	print OUT "nameserver $1\n";
      }
    }
  }
  close(OUT);
  exit(0);
} else {
  die "$0 called in unknown context.";
}