check if IP is available using Net::Ping

[pxelator] / bin / dhcpd.pl

diff --git a/bin/dhcpd.pl b/bin/dhcpd.pl
index c7913f6..059f9f7 100755 (executable)
--- a/bin/dhcpd.pl
+++ b/bin/dhcpd.pl
@@ -8,11 +8,13 @@ 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 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 @@ sub client_ip {
 
        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 @@ while (1) {
 
        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 @@ while (1) {
                        $file = 'undionly.kpxe';
                }
 
-               my $packet = new Net::DHCP::Packet(
+               my $packet = {
                        Op              => BOOTREPLY(),
                        Hops    => $dhcp->hops(),
                        Xid             => $dhcp->xid(),
@@ -119,11 +124,35 @@ while (1) {
                        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(