#!/usr/bin/perl 
#
# QnD xlate ISC dhcpd to dnsmasq
# 2009-11-04 KWY

my $pat_ip = '\d+\.\d+\.\d+\.\d+';
my ($net_name, $subnet, $netmask,
   $net_from, $net_to,
	$router, $dns, $range_bootp, 
	$tftp, $tftp_file,
	$lease, $lease_max);

$net_name = 'default';

sub sanitize_host {
	my $host = shift;
	$host =~ /^([\w-_]*)/;
	$host = $1;
	return $host;
}

sub read_host {
	my $host = shift;
	$host = sanitize_host($host);
	my ($ip, $mac, $dns, $tftp, $filename, $router);
	while(<STDIN>){
		/^\s*#/ and next; # ignore comments
	# the host definition may end on same line.
		/hardware ethernet ([^;]*)/ and
			$mac = $1 or
		/fixed-address ($pat_ip)/ and
			$ip = $1 or
		/option routers ([^;]*)/ and
			$router = $1 and
			print "dhcp-option=host:$host, option:router,$router\n" or
		/option domain-name-servers ([^;]*)/ and
			$dns = $1 and print "server=host:$host, $dns\n" or
		/next-server ($pat_ip)/ and
			$tftp = $1 or
		/filename "([^"]*)"/ and
			$filename = $1 or
		/}/ and last;
	}
	print "dhcp-host=";
	print "$mac," if $mac;
	print "$host";
	print ",$ip" if $ip;
	print "\n";
   print "dhcp-boot=host:$host, $filename,$tftp\n" if $tftp;
	return 1; #gotta give something true
}

sub read_subnet {
	my $subnet = shift;
	while(<STDIN>){
		/range ([\w-]*) ($pat_ip) ($pat_ip)/ and
			$net_from = $2 and $net_to = $3 and
		/option routers ([^;]*)/ and
			$router = $1 and 
			print "dhcp-option=net:$net_name, option:router,$router\n" or
		/option domain-name-servers ([^;]*)/ and
			$dns = $1 and print "server=$dns\n" or
		/next-server ($pat_ip)/ and
			$tftp = $1 or
		/filename "([^"]*)"/ and
			$filename = $1 or
		/default-lease-time (\d*)/ and
			$lease = $1 or
		/max-lease-time (\d*)/ and
			$lease_max = $1 and print "dhcp-lease-max=$lease_max\n" or
		/host ([^ ]*) / and
			$host = $1 and read_host($host) and next or
		/}/ and last;
	}
	print "dhcp-range=$net_name,$net_from,$net_to,$lease\n";
	print "dhcp-boot=net:$net_name , $filename,$tftp\n" if $tftp;
}


sub read_net {
	my $net_name = shift;
	while(<STDIN>){
		/^\s*#/ and next; # ignore comments
		/subnet ($pat_ip) netmask ($pat_ip)/ and
			$subnet = $1 and $netmask = $2 and
			print "# name: $net_name ip: $subnet mask: $netmask\n" and
			read_subnet($subnet) or
		/}/ and last;
	}
	return 1;

}
my %dhcp;
while(<>){
		/^\s*#/ and next; # ignore comments
		/shared-network ([^\s]*)/ and
			$net_name = $1 and read_net($net_name)
}