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 use Net::Ping;
  22
  23 use lib '..';
  24 use Net::DHCP::Packet;
  25 use Net::DHCP::Constants 0.67;
  26
  27 use server;
  28 my $debug = server::debug;
  29
  30 if ( ! $server::ip ) {
  31         my $server_ip = `/sbin/ifconfig`;
  32         $server_ip =~ s/^.+?addr:([\d\.]+).*$/$1/gs;
  33         $server::ip = $server_ip;
  34 }
  35
  36 warn "server ip $server::ip range: $server::ip_from - $server::ip_to\n";
  37
  38 my $addr = $server::ip_from;
  39
  40 sub client_ip {
  41         my ( $mac ) = @_;
  42
  43         my $conf = $server::conf;
  44         mkdir $conf unless -e $conf;
  45
  46         if ( -e "$conf/mac/$mac" ) {
  47                 my $ip = read_file "$conf/mac/$mac";
  48                 print "RENEW $mac $ip\n";
  49                 return $ip;
  50         }
  51
  52         my $p = Net::Ping->new;
  53
  54         my $prefix = $server::ip;
  55         $prefix =~ s{\.\d+$}{.};
  56         my $ip = $prefix . $addr;
  57
  58         while ( -e "$conf/ip/$ip" || $p->ping( $ip ) ) {
  59                 $ip = $prefix . $addr++;
  60                 die "all addresses allocated!" if $addr == $server::ip_to;
  61         }
  62
  63         write_file "$conf/mac/$mac", $ip;
  64
  65         my $ip_path = "$conf/ip/$ip";
  66         mkdir $ip_path unless -e $ip_path;
  67
  68         if ( -l "$ip_path/mac" && readlink "$ip_path/mac" ne "$conf/mac/$mac" ) {
  69                 warn "$mac IP changed from ", readlink "$ip_path/mac", " to $ip";
  70                 unlink "$ip_path/mac";
  71         };
  72         symlink "$conf/mac/$mac", "$ip_path/mac";
  73
  74         print "$mac NEW $ip\n";
  75
  76         return $ip;
  77 }
  78
  79 use log;
  80 use config;
  81 use pxelinux;
  82
  83 our $file;
  84 our $transaction = 0; # FIXME predictible transaction numbers
  85
  86 sub process_packet {
  87         my $sock = shift;
  88
  89         server->refresh;
  90
  91         my $buf;
  92         $sock->recv($buf, 1024);
  93         my $size = 'empty';
  94         $size = length($buf) . ' bytes' if defined $buf;
  95
  96         print "packet from ",$sock->peerhost,":",$sock->peerport," $size\n" if $debug;
  97         return unless $buf;
  98
  99         my $dhcp = Net::DHCP::Packet->new($buf);
 100         $dhcp->comment( $transaction++ );
 101
 102         warn "recv: ", $dhcp->toString if $debug;
 103
 104         my $mac = substr($dhcp->chaddr(),0,$dhcp->hlen()*2);
 105         my $ip = client_ip($mac);
 106
 107 =for later
 108
 109         my $user_class = $dhcp->getOptionValue(DHO_USER_CLASS());
 110
 111         if ( $user_class eq 'gPXE' ) {
 112                 $file = $gpxe_file;
 113         } elsif ( ! $file ) {
 114                 $file = 'undionly.kpxe';
 115         }
 116
 117 =cut
 118
 119         config::for_ip( $ip );
 120
 121         my $packet = {
 122                 Op              => BOOTREPLY(),
 123                 Hops    => $dhcp->hops(),
 124                 Xid             => $dhcp->xid(),
 125                 Flags   => $dhcp->flags(),
 126                 Ciaddr  => $dhcp->ciaddr(),
 127                 Yiaddr  => $ip,
 128                 Siaddr  => $server::ip,
 129                 Giaddr  => $dhcp->giaddr(),
 130                 Chaddr  => $dhcp->chaddr(),
 131                 File    => $file,
 132         };
 133
 134         foreach my $opt ( 'magic', 'config_file', 'path_prefix', 'reboot_time' ) {
 135                 my $DH0 = eval 'DHO_PXELINUX_' . uc $opt;
 136                 warn "DH0: $@" if $@;
 137                 my $v = eval "\$pxelinux::$opt";
 138                 warn "v: $@" if $@;
 139                 next unless defined $v;
 140                 warn "pxelinux dhcp option $opt = $DH0 = $v";
 141                 $packet->{ $DH0 } = $v;
 142         }
 143
 144         my $messagetype = $dhcp->getOptionValue(DHO_DHCP_MESSAGE_TYPE());
 145
 146         if ($messagetype eq DHCPDISCOVER()) {
 147                 log::mac $mac, "DHCP DISCOVER";
 148                 $packet->{Comment} = $dhcp->comment();
 149                 $packet->{DHO_DHCP_MESSAGE_TYPE()} = DHCPOFFER();
 150         } elsif ($messagetype eq DHCPREQUEST()) {
 151                 my $requested_ip = $dhcp->getOptionValue(DHO_DHCP_REQUESTED_ADDRESS());
 152                 log::mac $mac, "DHCP REQUEST $requested_ip $ip $file";
 153                 if ( $ip eq $requested_ip ) {
 154                         $packet->{DHO_DHCP_MESSAGE_TYPE()}      = DHCPACK();
 155                         $packet->{DHO_DHCP_LEASE_TIME()}        = 5 * 60; # 5 min
 156 #                       $packet->{DHO_DHCP_SERVER_IDENTIFIER()} = $server::ip;          # FIXME
 157                         $packet->{DHO_SUBNET_MASK()}            = '255.255.255.0';
 158                         $packet->{DHO_ROUTERS()}                = $server::ip;
 159                         $packet->{DHO_DOMAIN_NAME()}            = 'pxelator.lan';
 160                         $packet->{DHO_NAME_SERVERS()}           = $server::ip;
 161 #                       $packet->{DHO_ROOT_PATH()}              = '/exports/foobar';
 162                 } else {
 163                         $packet->{DHO_DHCP_MESSAGE_TYPE()} = DHCPNAK();
 164                         $packet->{DHO_DHCP_MESSAGE()} = "Bad request, expected $ip";
 165                 }
 166         } elsif ($messagetype eq DHCPINFORM()) {
 167                 log::mac $mac, "DHCP INFORM ignored";
 168         } else {
 169                 log::mac $mac, "$messagetype igored (bootp?)";
 170         }
 171
 172         warn ">> $mac == $ip server: $server::ip", $file ? " file: $file\n" : "\n" if $debug;
 173
 174 warn "## created packet ", dump( $packet );
 175
 176         $packet = new Net::DHCP::Packet( %$packet );
 177         warn "send ",$packet->toString() if $debug;
 178
 179         my $reply = IO::Socket::INET->new(
 180                 LocalAddr => $server::ip,
 181                 LocalPort => 67,
 182                 Proto => "udp",
 183                 Broadcast => 1,
 184                 PeerAddr => '255.255.255.255',
 185                 PeerPort => 68,
 186                 Reuse => 1,
 187         ) or die "socket: $@";
 188
 189         my $buff = $packet->serialize();
 190         $reply->send( $buff, 0 ) or die "Error sending: $!\n";
 191
 192 #       system("arp -s $ip $mac"),
 193
 194 }
 195
 196 sub start {
 197
 198         my $sock = IO::Socket::INET->new(
 199                 LocalPort       => 67,
 200 #               LocalAddr       => 'localhost',
 201 #               LocalAddr       => '10.0.0.100',
 202                 LocalAddr       => '0.0.0.0',
 203                 Proto           => 'udp',
 204                 ReuseAddr       => 1,
 205 #               PeerPort        => getservbyname('bootpc', 'udp'),
 206                 Broadcast       => 1,
 207                 Type            => SOCK_DGRAM,
 208         ) or die "Failed to bind to socket: $@";
 209
 210         print "DHCP listen on ",$sock->sockhost,":",$sock->sockport,"\n";
 211
 212         while (1) {
 213                 process_packet $sock;
 214         }
 215 }
 216
 217 warn "loaded";
 218
 219 1;