#!/usr/bin/perl
#  
#  This script uses the named D-BUS support, which must be enabled in
#  the running named with the named '-D' option, to get and print the
#  list of forwarding zones in the running server.
#
#  It accepts an optional <zone> first argument which is the DNS name
#  of the zone whose forwarders (if any) will be retrieved.
#
#  If no zone argument is specified, all forwarding zones will be listed.
#
#  Usage: GetForwarders [-n -r] [ <zone> ]
#    -n : output forward zone statements for named.conf
#    -r : output in resolv.conf format
#       : no -r or -n: just list the forwarders
#
#  Copyright(C) Jason Vas Dias<jvdias@redhat.com> Red Hat Inc. 2005
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation at
#           http://www.fsf.org/licensing/licenses/gpl.txt
#  and included in this software distribution as the "LICENSE" file.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
use Getopt::Std;

%opts=();

getopts("rn",\%opts);

$zone = '';
if ( $#ARGV >= 0 )
{
    $zone = "string:'". join("' string:'",@ARGV)."'";
};

@dn=(); 

open(DNS,
     '/usr/bin/dbus-send --system --type=method_call --print-reply --reply-timeout=20000 '
    .'--dest=com.redhat.named /com/redhat/named com.redhat.named.text.GetForwarders '
    .$zone .'|'
    ) || die("dbus-send failed: $?: $!");

while(<DNS>)
{ 
    $_=~s/[\s\r\n]+$//;
    if ( /(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})/ )
    { # nameserver address
	push @{${$dn[-1]}{'s'}}, { 'a' => "$1.$2.$3.$4" }; 
    }elsif
       ( /\"(\d+)\"$/ )      
    { # port
	if ( $1 != 53 )
	{
	    ${@{${$dn[-1]}{'s'}}[-1]}{'p'} = $1;
	};
    }elsif
       ( /string\s+\"([^\"]+)\"$/ )
    { 
	if ( ($1 eq 'first') || ($1 eq 'only') )
	{ # policy
	    if( $1 eq 'only' )
	    { # not default
		${$dn[-1]}{'o'} = 1;
	    }
	}else
	{ # new DN - "zone"
	    push @dn, {'n'=>$1,'s'=>[]}; 
	};
    }; 
};
close(DNS);

if( exists($opts{'r'}) )
{ # resolv.conf style:
    my %svrs=();
    print 'search ', 
          join( ' ', 
		grep { !( $_ =~ /\.in-addr\.arpa$/) }
		map  { ${$_}{'n'} }
		@dn
	      ),"\n",
          'nameserver ',
	  join( "\nnameserver ",
		grep { exists ( $svrs{ $_ } ) ? undef : { $svrs{$_}=$_ } } 
		map  { ${$_}{'a'} }
		map  { @{${$_}{'s'}} } @dn			     
	      ),"\n";
}elsif( exists($opts{'n'}) )
{ # named.conf style:
    foreach $d (@dn)
    {
	print 'zone "',${$d}{'n'},'." IN { type forward; forwarders { ',
	      join("; ",
		   map { exists( ${$_}{'p'} ) 
			 ? ${$_}{'a'} . ' port ' . ${$_}{'p'}  
			 : ${$_}{'a'}
		       } @{${$d}{'s'}}
		  ),
	      '; }; ',
	      exists(${$d}{'o'}) ? ' forward only; ' : '',
              "};\n";
    };
}else
{ # just list:
    foreach $d (@dn)
    {
	print  ${$d}{'n'}, "\n\t", 
	       (exists(${$d}{'o'}) ? "forward only\n\t" : ''),
	       join( "\n\t",	
		     map { exists( ${$_}{'p'} )
			   ? ${$_}{'a'} . ':' . ${$_}{'p'} 
			   : ${$_}{'a'}
		         } @{${$d}{'s'}}
		   ),"\n";
    };
};