#!/usr/bin/perl


####################################################################
#                   Edit These for Your Domain                     #
####################################################################


$LEASES = "/var/lib/dhcp3/dhcpd.leases";

$DOMAIN = "lan.domain.org";
$REVERSE = "168.192.in-addr.arpa";

$FORWARD_BASE = "ou=forward,ou=dns,dc=lan,dc=domain,dc=org";
$REVERSE_BASE = "ou=reverse,ou=dns,dc=lan,dc=domain,dc=org";

$USER = 'uid=dnsupdate,ou=users,dc=lan,dc=domain,dc=org';
$PASSWORD = "password";

$LDAP_HOST = 'localhost';

$UPDATE_TIME = 30;    # In Seconds

$AUTO_VERIFY = 0;     # Set this to positive if you would like dhcp2ldap
                      # to periodically re-read the entire leases file
		      # even if the time stamp hasn't changed
		      #
		      # It will perform the auto-verify after 
		      # ($AUTO_VERIFY * $UPDATE_TIME) seconds
		      # 
		      # This is probably a good idea unless your parse times
		      # are incredibly high

####################################################################
#                   Do Not Edit Below This Line                    #
####################################################################

use IO::Socket;
use Net::LDAP;

print "Initializing LDAP Connection...";
$ldap = Net::LDAP->new($LDAP_HOST) or die "$@";
$ldap->bind($USER, password => $PASSWORD) or die "$!\n";
print "Done\n";

$params = shift;

if($params eq "-d"){
	daemonize();
}
if($params eq "-h"){
	usage();
	exit;
}

while(1){

	if(changed($LEASES)){
		parse($LEASES);
		do_stuff();
	}

	sleep $UPDATE_TIME;
}


sub changed{
	my $file = shift;
	my $curstat = (stat($file))[9];
	
	if($AUTO_VERIFY){
		$check_count++;
	}
	
	if($oldstat != $curstat || (($check_count == $AUTO_VERIFY) && $AUTO_VERIFY)){
		$oldstat = $curstat;
		$check_count = 0;

		print "Timestamp change or AUTO_VERIFY triggered...\n";
		return 1;
	}
	else{
		return 0;
	}
}


sub daemonize{
        chdir '/';
        umask 0;
        open STDIN, '/dev/null';
        open STDOUT, '/dev/null';
        open STDERR, '/dev/null';

        if(fork()){
                exit;
        }
        else{
                setsid;
                return;
        }
}

sub parse{
	my $ip,$hostname;

	open IN, shift or die "Could not open leases file: $!\n";
	while($_ = <IN>){
		if(/^#/){
			next;
		}
		chomp $_;
		if(/lease/){
			/\d{1,3}.\d{1,3}.\d{1,3}.\d{1,3}/;
			$ip = $&;
			while(!(/\}/)){
				$_ = <IN>;
				if(/client-hostname/){
					/\".*\"/;
					$_ = $&;
					/\w+\S*\w+/;
					$_ = $&;
					$hostname = lc;
					$hosts{$hostname} = $ip;	
				}
			}
		}
		$line = "";

	};
	close IN;
}


sub do_stuff{
	my $readd, $host, $ip, $hostname;
	while(($host,$ip) = each(%hosts)){
		$hostname = $host . "." . $DOMAIN . ".";
		$lookup = "";
		eval{$lookup = inet_ntoa((gethostbyname("$host.$DOMAIN"))[4]); };
		($first,$second,$third,$fourth) = split(/\./,$ip);

		if($lookup eq $ip){
			next;
		}

		elsif($lookup ne $ip){
			print "Removing inaccurate records for $host...\n";
			$result = $ldap->delete("relativeDomainName=$host," . $FORWARD_BASE);
			$result->code && warn "failed to remove entry: ", $result->error ;
			$result = $ldap->delete("relativeDomainName=$fourth.$third," . $REVERSE_BASE);
			$result->code && warn "failed to remove entry: ", $result->error ;
			$readd = 1;
		}

		if(!$lookup || $readd){
			print "Adding entry for $host at $ip...\n";
			$result = $ldap->add( "relativeDomainName=$host," . $FORWARD_BASE,
				attr => [
					'relativeDomainName'=> $host,
					'objectClass'=> ['top','dNSZone'],
					'dNSTTL' => '7200',
					'zoneName' => $DOMAIN,
					'aRecord' => $ip
					]
				);
			$result->code && warn "failed to add entry: ", $result->error ;

			$result = $ldap->delete("relativeDomainName=$fourth.$third," . $REVERSE_BASE);
                        $result->code && warn "failed to remove entry: ", $result->error ;
			
			$result = $ldap->add( "relativeDomainName=$fourth.$third," . $REVERSE_BASE,
				attr => [
					'relativeDomainName'=> "$fourth.$third",
					'objectClass'=> ['top','dNSZone'],
					'dNSTTL' => '7200',
					'zoneName' => $REVERSE,
					'pTRRecord' => $hostname 
					]
				);	
			$result->code && warn "failed to add entry: ", $result->error ;
			$readd = 0;	
		}
		

	}
}

sub usage{
	print <<EOF;

dhcp2ldapd v1.1: Dynamic DNS Updates for the Bind9 LDAP backend
Copyright 2005 Travis Groth <travis\@netfoo.org> under the GNU GPL

Usage:
	dhcp2ldapd [-d | -h]

-d runs dhcp2ldap in daemon mode
-h displays this help message

Please edit the config variables before running!

EOF
}


#############################################################################
#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; either version 2 of the License, or
#(at your option) any later version.
#
#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.
#
#You should have received a copy of the GNU General Public License
#along with this program; if not, write to the Free Software			
#Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA  
#############################################################################