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