git.rot13.org Git - pxelator/blob - bin/dhcpd.pl

   1 #!/usr/bin/perl
   2
   3 # based on http://www.perlmonks.org/index.pl?node_id=325248
   4
   5 use strict;
   6 use warnings;
   7
   8 use IO::Socket::INET;
   9 use Net::DHCP::Packet;
  10 use Net::DHCP::Constants;
  11 use Data::Dump qw/dump/;
  12
  13 die "need to run $0 as root like this\nsudo $0\n" unless $< == 0;
  14
  15 my $debug = shift @ARGV;
  16
  17 our ( $server_ip, $next_file );
  18 require "config.pl";
  19
  20 my $sock = IO::Socket::INET->new(
  21         LocalPort       => 67,
  22 #       LocalAddr       => 'localhost',
  23 #       LocalAddr       => '10.0.0.100',
  24         LocalAddr       => '0.0.0.0',
  25         Proto           => 'udp',
  26         ReuseAddr       => 1,
  27 #       PeerPort        => getservbyname('bootpc', 'udp'),
  28         Broadcast       => 1,
  29         Type            => SOCK_DGRAM,
  30 ) or die "Failed to bind to socket: $@";
  31
  32 my $_ip = 10;
  33 my $_mac2ip;
  34
  35 sub client_ip {
  36         my ( $mac ) = @_;
  37
  38         my $ip = $_mac2ip->{$mac};
  39         return $ip if $ip;
  40
  41         $ip = $server_ip;
  42         $ip =~ s{\.\d+$}{.$_ip};
  43         $_mac2ip->{$mac} = $ip;
  44
  45         $_ip++;
  46         if ( $_ip == 100 ) {
  47                 warn "IP roll-over to 10\n";
  48                 $_ip = 10;
  49         }
  50
  51         return $ip;
  52 }
  53
  54 while (1) {
  55
  56         print "waiting for DHCP requests on ",$sock->sockhost,":",$sock->sockport,"\n";
  57
  58         my $buf;
  59         $sock->recv($buf, 1024);
  60         print "<< peer:",$sock->peerhost,":",$sock->peerport,"\n";
  61
  62         if (defined $buf) {
  63
  64                 my $dhcp;
  65
  66                 eval { $dhcp = Net::DHCP::Packet->new($buf); };
  67                 die "can't use request", dump( $buf ) if $@;
  68
  69                 if ( $debug ) {
  70                         warn "recv: ", $dhcp->toString, "\n\n";
  71                 }
  72
  73                 my $mac = substr($dhcp->chaddr(),0,$dhcp->hlen()*2);
  74                 my $ip = client_ip($mac);
  75
  76                 my $file =  $next_file;
  77                 $file = 'undionly.kpxe' if ! $file || $dhcp->getOptionValue(DHO_USER_CLASS()) ne 'gPXE';
  78
  79                 my $packet = new Net::DHCP::Packet(
  80                         Op              => BOOTREPLY(),
  81                         Hops    => $dhcp->hops(),
  82                         Xid             => $dhcp->xid(),
  83                         Flags   => $dhcp->flags(),
  84                         Ciaddr  => $dhcp->ciaddr(),
  85                         Yiaddr  => $ip,
  86                         Siaddr  => $server_ip,
  87                         Giaddr  => $dhcp->giaddr(),
  88                         Chaddr  => $dhcp->chaddr(),
  89                         File    => $file,
  90 #                       DHO_DHCP_MESSAGE_TYPE() => DHCPACK(),
  91                 DHO_SUBNET_MASK() => '255.0.0.0',
  92                 );
  93
  94                 warn ">> $mac == $ip server $server_ip\n";
  95
  96                 warn "## ",$packet->toString(),"\n" if $debug;
  97
  98                 my $reply = IO::Socket::INET->new(
  99                         LocalAddr => $server_ip,
 100                         LocalPort => 67,
 101                         Proto => "udp",
 102                         Broadcast => 1,
 103                         PeerAddr => '255.255.255.255',
 104                         PeerPort => 68,
 105                         Reuse => 1,
 106                 ) or die "socket: $@";
 107
 108                 my $buff = $packet->serialize();
 109                 $reply->send( $buff, 0 ) or die "Error sending: $!\n";
 110
 111 #               system("arp -s $ip $mac"),
 112
 113         } else {
 114                 print "No bootp request.\n";
 115         }
 116
 117 }