git.rot13.org Git - pxelator/blob - lib/PXElator/dhcpd.pm

   1 package dhcpd;
   2
   3 =head1 dhcpd
   4
   5 start with:
   6
   7  perl -Ilib/PXElator -Ilib -Mdhcpd -e start
   8
   9 based on L<http://www.perlmonks.org/index.pl?node_id=325248>
  10
  11 =cut
  12
  13 use strict;
  14 use warnings;
  15
  16 use autodie;
  17
  18 use IO::Socket::INET;
  19 use File::Slurp;
  20 use Data::Dump qw/dump/;
  21
  22 use lib '..';
  23 use Net::DHCP::Packet;
  24 use Net::DHCP::Constants 0.67;
  25
  26 use server;
  27 my $debug = server::debug;
  28
  29 if ( ! $server::ip ) {
  30         my $server_ip = `/sbin/ifconfig`;
  31         $server_ip =~ s/^.+?addr:([\d\.]+).*$/$1/gs;
  32         $server::ip = $server_ip;
  33 }
  34
  35 warn "server ip $server::ip range: $server::ip_from - $server::ip_to\n";
  36
  37 use client;
  38
  39 sub client_ip {
  40         my ( $mac ) = @_;
  41
  42         my $conf = $server::conf;
  43         mkdir $conf unless -e $conf;
  44
  45         my $ip;
  46
  47         if ( -e "$conf/mac/$mac" ) {
  48                 $ip = read_file "$conf/mac/$mac";
  49                 print "RENEW $mac $ip\n";
  50                 return $ip;
  51         } else {
  52                 $ip = client::next_ip;
  53                 print "NEW $mac $ip\n";
  54                 write_file "$conf/mac/$mac", $ip;
  55         }
  56
  57         my $ip_path = "$conf/ip/$ip";
  58         mkdir $ip_path unless -e $ip_path;
  59
  60         if ( -l "$ip_path/mac" && readlink "$ip_path/mac" ne "$conf/mac/$mac" ) {
  61                 warn "$mac IP changed from ", readlink "$ip_path/mac", " to $ip";
  62                 unlink "$ip_path/mac";
  63         };
  64
  65         symlink "$conf/mac/$mac", "$ip_path/mac";
  66
  67         return $ip;
  68 }
  69
  70 use log;
  71 use config;
  72 use pxelinux;
  73 use client;
  74
  75 our $file;
  76 our $transaction = 0; # FIXME predictible transaction numbers
  77
  78 sub process_packet {
  79         my $sock = shift;
  80
  81         server->refresh;
  82
  83         my $buf;
  84         $sock->recv($buf, 1024);
  85         my $size = 'empty';
  86         $size = length($buf) . ' bytes' if defined $buf;
  87
  88         print "packet from ",$sock->peerhost,":",$sock->peerport," $size\n" if $debug;
  89         return unless $buf;
  90
  91         my $dhcp = Net::DHCP::Packet->new($buf);
  92         $dhcp->comment( $transaction++ );
  93
  94         warn "recv: ", $dhcp->toString if $debug;
  95
  96         my $mac = substr($dhcp->chaddr(),0,$dhcp->hlen()*2);
  97         my $ip = client_ip($mac);
  98
  99 =for later
 100
 101         my $user_class = $dhcp->getOptionValue(DHO_USER_CLASS());
 102
 103         if ( $user_class eq 'gPXE' ) {
 104                 $file = $gpxe_file;
 105         } elsif ( ! $file ) {
 106                 $file = 'undionly.kpxe';
 107         }
 108
 109 =cut
 110
 111         config::for_ip( $ip );
 112
 113         my $packet = {
 114                 Op              => BOOTREPLY(),
 115                 Hops    => $dhcp->hops(),
 116                 Xid             => $dhcp->xid(),
 117                 Flags   => $dhcp->flags(),
 118                 Ciaddr  => $dhcp->ciaddr(),
 119                 Yiaddr  => $ip,
 120                 Siaddr  => $server::ip,
 121                 Giaddr  => $dhcp->giaddr(),
 122                 Chaddr  => $dhcp->chaddr(),
 123                 File    => $file,
 124                 DHO_DHCP_SERVER_IDENTIFIER()    => $server::ip, # busybox/udhcpc needs it but doesn't request
 125         };
 126
 127         my $options = {
 128                 DHO_SUBNET_MASK()       => $server::netmask,
 129                 DHO_ROUTERS()           => $server::ip,
 130                 DHO_DOMAIN_NAME()       => $server::domain_name,
 131                 DHO_NAME_SERVERS()      => $server::ip,
 132                 DHO_DOMAIN_NAME_SERVERS() => $server::ip,
 133                 DHO_HOST_NAME()         => client::conf( $ip, 'hostname' ),
 134                 DHO_BROADCAST_ADDRESS() => $server::bcast,
 135 #               DHO_NTP_SERVERS() => '',
 136         };
 137
 138         my @requested = split(/\s/, $dhcp->getOptionValue(DHO_DHCP_PARAMETER_REQUEST_LIST));
 139         warn "options ",dump( $options ), ' requested: ',dump( @requested ) if $debug;
 140
 141         my @missing;
 142         foreach ( @requested ) {
 143                 if ( defined $options->{$_} ) {
 144                         $packet->{$_} = $options->{$_};
 145                 } else {
 146                         push @missing, $_;
 147                 }
 148         }
 149
 150         warn "W: options requested but missing: ",dump( @missing ),$/;
 151
 152         foreach my $opt ( 'magic', 'config_file', 'path_prefix', 'reboot_time' ) {
 153                 my $DH0 = eval 'DHO_PXELINUX_' . uc $opt;
 154                 warn "DH0: $@" if $@;
 155                 my $v = eval "\$pxelinux::$opt";
 156                 warn "v: $@" if $@;
 157                 next unless defined $v;
 158                 warn "pxelinux dhcp option $opt = $DH0 = $v\n" if $debug;
 159                 $packet->{ $DH0 } = $v;
 160         }
 161
 162         my $messagetype = $dhcp->getOptionValue(DHO_DHCP_MESSAGE_TYPE());
 163
 164         if ($messagetype eq DHCPDISCOVER()) {
 165                 log::mac $mac, "DHCP DISCOVER";
 166                 $packet->{Comment} = $dhcp->comment();
 167                 $packet->{DHO_DHCP_MESSAGE_TYPE()} = DHCPOFFER();
 168         } elsif ($messagetype eq DHCPREQUEST()) {
 169                 my $requested_ip = $dhcp->getOptionValue(DHO_DHCP_REQUESTED_ADDRESS());
 170                 log::mac $mac, "DHCP REQUEST $requested_ip $ip $file";
 171                 if ( $ip eq $requested_ip ) {
 172                         $packet->{DHO_DHCP_MESSAGE_TYPE()}      = DHCPACK();
 173                         $packet->{DHO_DHCP_LEASE_TIME()}        = 5 * 60; # 5 min
 174 #                       $packet->{DHO_ROOT_PATH()}              = '/exports/foobar';
 175                 } else {
 176                         $packet->{DHO_DHCP_MESSAGE_TYPE()} = DHCPNAK();
 177                         $packet->{DHO_DHCP_MESSAGE()} = "Bad request, expected $ip";
 178                 }
 179         } elsif ($messagetype eq DHCPINFORM()) {
 180                 log::mac $mac, "DHCP INFORM ignored";
 181         } else {
 182                 log::mac $mac, "$messagetype igored (bootp?)";
 183         }
 184
 185         warn ">> $mac == $ip server: $server::ip", $file ? " file: $file\n" : "\n" if $debug;
 186
 187         $packet = new Net::DHCP::Packet( %$packet );
 188         warn "send ",$packet->toString() if $debug;
 189
 190         my $reply = IO::Socket::INET->new(
 191                 LocalAddr => $server::ip,
 192                 LocalPort => 67,
 193                 Proto => "udp",
 194                 Broadcast => 1,
 195                 PeerAddr => '255.255.255.255',
 196                 PeerPort => 68,
 197                 Reuse => 1,
 198         ) or die "socket: $@";
 199
 200         my $buff = $packet->serialize();
 201         $reply->send( $buff, 0 ) or die "Error sending: $!\n";
 202
 203 #       system("arp -s $ip $mac"),
 204
 205 }
 206
 207 sub start {
 208
 209         my $sock = IO::Socket::INET->new(
 210                 LocalPort       => 67,
 211 #               LocalAddr       => 'localhost',
 212 #               LocalAddr       => '10.0.0.100',
 213                 LocalAddr       => '0.0.0.0',
 214                 Proto           => 'udp',
 215                 ReuseAddr       => 1,
 216 #               PeerPort        => getservbyname('bootpc', 'udp'),
 217                 Broadcast       => 1,
 218                 Type            => SOCK_DGRAM,
 219         ) or die "Failed to bind to socket: $@";
 220
 221         print "DHCP listen on ",$sock->sockhost,":",$sock->sockport,"\n";
 222
 223         while (1) {
 224                 process_packet $sock;
 225         }
 226 }
 227
 228 warn "loaded";
 229
 230 1;