--- bin/dhcpd.pl	2009/07/27 11:46:44	8
+++ bin/dhcpd.pl	2009/07/29 00:59:55	28
@@ -5,17 +5,31 @@
 use strict;
 use warnings;
 
+use autodie;
+
 use IO::Socket::INET;
-use Net::DHCP::Packet;
-use Net::DHCP::Constants;
+use File::Slurp;
 use Data::Dump qw/dump/;
 
+use lib 'lib';
+use Net::DHCP::Packet;
+use Net::DHCP::Constants 0.67;
 die "need to run $0 as root like this\nsudo $0\n" unless $< == 0;
 
 my $debug = shift @ARGV;
 
-our ( $server_ip, $next_file );
-require "config.pl";
+our ( $file, $gpxe_file );
+our ( $ip_from, $ip_to ) = ( 10, 100 );
+
+our $server_ip = readlink 'conf/server.ip' if -l 'conf/server.ip';
+
+if ( ! $server_ip ) {
+	$server_ip = `/sbin/ifconfig`;
+	$server_ip =~ s/^.+?addr:([\d\.]+).*$/$1/gs;
+	warn "auto-configure server ip to $server_ip\n";
+} else {
+	warn "server ip $server_ip\n";
+}
 
 my $sock = IO::Socket::INET->new(
 	LocalPort	=> 67,
@@ -29,54 +43,70 @@
 	Type		=> SOCK_DGRAM,
 ) or die "Failed to bind to socket: $@";
 
-my $_ip = 10;
-my $_mac2ip;
+
+my $addr = $ip_from;
 
 sub client_ip {
 	my ( $mac ) = @_;
 
-	my $ip = $_mac2ip->{$mac};
-	return $ip if $ip;
+	my $conf = "conf/$server_ip";
+	mkdir $conf unless -e $conf;
 
-	$ip = $server_ip;
-	$ip =~ s{\.\d+$}{.$_ip};
-	$_mac2ip->{$mac} = $ip;
-
-	$_ip++;
-	if ( $_ip == 100 ) {
-		warn "IP roll-over to 10\n";
-		$_ip = 10;
+	if ( -e "$conf/mac/$mac" ) {
+		my $ip = read_file "$conf/mac/$mac";
+		print "$mac old $ip\n";
+		return $ip;
 	}
 
+	mkdir $_ foreach grep { ! -e $_ } map { "$conf/$_" } ( 'ip', 'mac' );
+
+	my $prefix = $server_ip;
+	$prefix =~ s{\.\d+$}{.};
+	my $ip = $prefix . $addr;
+	while ( -e "conf/ip/$ip" ) {
+		$ip = $prefix . $addr++;
+		die "all addresses allocated!" if $addr == $ip_to;
+	}
+
+	write_file "$conf/mac/$mac", $ip;
+	unlink     "$conf/ip/$ip" if -e "$conf/ip/$ip";
+	symlink    "$conf/mac/$mac", "$conf/ip/$ip";
+
+	print "$mac NEW $ip\n";
+
 	return $ip;
 }
 
+my $transaction = 0; # FIXME predictible transaction numbers
+
 while (1) {
 
+	require "config.pl"; # refresh config
+
 	print "waiting for DHCP requests on ",$sock->sockhost,":",$sock->sockport,"\n";
 
 	my $buf;
 	$sock->recv($buf, 1024);
-	print "<< peer:",$sock->peerhost,":",$sock->peerport,"\n";
+	print "<< ",$sock->peerhost,":",$sock->peerport,"\n";
 
 	if (defined $buf) {
 
-		my $dhcp;
+		my $dhcp = Net::DHCP::Packet->new($buf);
+		$dhcp->comment( $transaction++ );
 
-		eval { $dhcp = Net::DHCP::Packet->new($buf); };
-		die "can't use request", dump( $buf ) if $@;
-
-		if ( $debug ) {
-			warn "recv: ", $dhcp->toString, "\n\n";
-		}
+		warn "recv: ", $dhcp->toString, "\n\n";
 
 		my $mac = substr($dhcp->chaddr(),0,$dhcp->hlen()*2);
 		my $ip = client_ip($mac);
+		my $user_class = $dhcp->getOptionValue(DHO_USER_CLASS());
 
-		my $file =  $next_file;
-		$file = 'undionly.kpxe' if ! $file || $dhcp->getOptionValue(DHO_USER_CLASS()) ne 'gPXE';
+		if ( $user_class eq 'gPXE' ) {
+			$file = $gpxe_file;
+		} elsif ( ! $file ) {
+			$file = 'undionly.kpxe';
+		}
 
-		my $packet = new Net::DHCP::Packet(
+		my $packet = {
 			Op		=> BOOTREPLY(),
 			Hops	=> $dhcp->hops(),
 			Xid		=> $dhcp->xid(),
@@ -88,11 +118,35 @@
 			Chaddr	=> $dhcp->chaddr(),
 			File	=> $file,
 #			DHO_DHCP_MESSAGE_TYPE() => DHCPACK(),
-        	DHO_SUBNET_MASK() => '255.0.0.0',
-		);
+#			DHO_SUBNET_MASK() => '255.255.255.0',
+		};
+
+		my $messagetype = $dhcp->getOptionValue(DHO_DHCP_MESSAGE_TYPE());
+
+		if ($messagetype eq DHCPDISCOVER()) {
+			warn "DHCP DISCOVER";
+			$packet->{Comment} = $dhcp->comment();
+			$packet->{DHO_DHCP_MESSAGE_TYPE()} = DHCPOFFER();
+		} elsif ($messagetype eq DHCPREQUEST()) {
+			my $requested_ip = $dhcp->getOptionValue(DHO_DHCP_REQUESTED_ADDRESS());
+			warn "DHCP REQUEST $requested_ip";
+			if ( $ip eq $requested_ip ) {
+				$packet->{DHO_DHCP_MESSAGE_TYPE()} = DHCPACK();
+				$packet->{DHO_DHCP_LEASE_TIME()}   = 100;
+			} else {
+				$packet->{DHO_DHCP_MESSAGE_TYPE()} = DHCPNAK();
+				$packet->{DHO_DHCP_MESSAGE()} = "Bad request, expected $ip";
+			}
+		} elsif ($messagetype eq DHCPINFORM()) {
+			warn "DHCP INFORM ignored";
+		} else {
+			warn "$messagetype igored (bootp?)";
+		}
+
+
+		warn ">> $mac == $ip server: $server_ip", $file ? " file: $file\n" : "\n";
 
-		warn ">> $mac == $ip server $server_ip\n";
-		
+		$packet = new Net::DHCP::Packet( %$packet );
 		warn "## ",$packet->toString(),"\n" if $debug;
 
 		my $reply = IO::Socket::INET->new(