--- bin/dhcpd.pl	2009/07/28 16:35:49	22
+++ bin/dhcpd.pl	2009/07/29 13:03:39	36
@@ -8,11 +8,13 @@
 use autodie;
 
 use IO::Socket::INET;
-use Net::DHCP::Packet;
-use Net::DHCP::Constants;
 use File::Slurp;
 use Data::Dump qw/dump/;
+use Net::Ping;
 
+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;
@@ -59,23 +61,30 @@
 
 	mkdir $_ foreach grep { ! -e $_ } map { "$conf/$_" } ( 'ip', 'mac' );
 
+	my $p = Net::Ping->new;
+
 	my $prefix = $server_ip;
 	$prefix =~ s{\.\d+$}{.};
 	my $ip = $prefix . $addr;
-	while ( -e "conf/ip/$ip" ) {
+	while ( -e "conf/ip/$ip" || $p->ping( $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/$ip";
+	if ( -l "$conf/ip/$ip" && readlink "$conf/ip/$ip" ne "$conf/mac/$mac") {
+		unlink     "$conf/ip/$ip";
+		symlink    "$conf/mac/$mac", "$conf/ip/$ip";
+		warn "$mac IP changed to $ip";
+	}
 
 	print "$mac NEW $ip\n";
 
 	return $ip;
 }
 
+my $transaction = 0; # FIXME predictible transaction numbers
+
 while (1) {
 
 	require "config.pl"; # refresh config
@@ -88,14 +97,10 @@
 
 	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);
@@ -107,7 +112,7 @@
 			$file = 'undionly.kpxe';
 		}
 
-		my $packet = new Net::DHCP::Packet(
+		my $packet = {
 			Op		=> BOOTREPLY(),
 			Hops	=> $dhcp->hops(),
 			Xid		=> $dhcp->xid(),
@@ -119,11 +124,35 @@
 			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\n";
+		warn ">> $mac == $ip server: $server_ip", $file ? " file: $file\n" : "\n";
 
+		$packet = new Net::DHCP::Packet( %$packet );
 		warn "## ",$packet->toString(),"\n" if $debug;
 
 		my $reply = IO::Socket::INET->new(