/[pxelator]/bin/dhcpd.pl
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Contents of /bin/dhcpd.pl

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Revision 28 - (show annotations)
Wed Jul 29 00:59:55 2009 UTC (10 years, 2 months ago) by dpavlin
File MIME type: text/plain
File size: 4040 byte(s)
added dhcp lease time to make ISC's dhclient happy

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 autodie;
9
10 use IO::Socket::INET;
11 use File::Slurp;
12 use Data::Dump qw/dump/;
13
14 use lib 'lib';
15 use Net::DHCP::Packet;
16 use Net::DHCP::Constants 0.67;
17 die "need to run $0 as root like this\nsudo $0\n" unless $< == 0;
18
19 my $debug = shift @ARGV;
20
21 our ( $file, $gpxe_file );
22 our ( $ip_from, $ip_to ) = ( 10, 100 );
23
24 our $server_ip = readlink 'conf/server.ip' if -l 'conf/server.ip';
25
26 if ( ! $server_ip ) {
27 $server_ip = `/sbin/ifconfig`;
28 $server_ip =~ s/^.+?addr:([\d\.]+).*$/$1/gs;
29 warn "auto-configure server ip to $server_ip\n";
30 } else {
31 warn "server ip $server_ip\n";
32 }
33
34 my $sock = IO::Socket::INET->new(
35 LocalPort => 67,
36 # LocalAddr => 'localhost',
37 # LocalAddr => '10.0.0.100',
38 LocalAddr => '0.0.0.0',
39 Proto => 'udp',
40 ReuseAddr => 1,
41 # PeerPort => getservbyname('bootpc', 'udp'),
42 Broadcast => 1,
43 Type => SOCK_DGRAM,
44 ) or die "Failed to bind to socket: $@";
45
46
47 my $addr = $ip_from;
48
49 sub client_ip {
50 my ( $mac ) = @_;
51
52 my $conf = "conf/$server_ip";
53 mkdir $conf unless -e $conf;
54
55 if ( -e "$conf/mac/$mac" ) {
56 my $ip = read_file "$conf/mac/$mac";
57 print "$mac old $ip\n";
58 return $ip;
59 }
60
61 mkdir $_ foreach grep { ! -e $_ } map { "$conf/$_" } ( 'ip', 'mac' );
62
63 my $prefix = $server_ip;
64 $prefix =~ s{\.\d+$}{.};
65 my $ip = $prefix . $addr;
66 while ( -e "conf/ip/$ip" ) {
67 $ip = $prefix . $addr++;
68 die "all addresses allocated!" if $addr == $ip_to;
69 }
70
71 write_file "$conf/mac/$mac", $ip;
72 unlink "$conf/ip/$ip" if -e "$conf/ip/$ip";
73 symlink "$conf/mac/$mac", "$conf/ip/$ip";
74
75 print "$mac NEW $ip\n";
76
77 return $ip;
78 }
79
80 my $transaction = 0; # FIXME predictible transaction numbers
81
82 while (1) {
83
84 require "config.pl"; # refresh config
85
86 print "waiting for DHCP requests on ",$sock->sockhost,":",$sock->sockport,"\n";
87
88 my $buf;
89 $sock->recv($buf, 1024);
90 print "<< ",$sock->peerhost,":",$sock->peerport,"\n";
91
92 if (defined $buf) {
93
94 my $dhcp = Net::DHCP::Packet->new($buf);
95 $dhcp->comment( $transaction++ );
96
97 warn "recv: ", $dhcp->toString, "\n\n";
98
99 my $mac = substr($dhcp->chaddr(),0,$dhcp->hlen()*2);
100 my $ip = client_ip($mac);
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 my $packet = {
110 Op => BOOTREPLY(),
111 Hops => $dhcp->hops(),
112 Xid => $dhcp->xid(),
113 Flags => $dhcp->flags(),
114 Ciaddr => $dhcp->ciaddr(),
115 Yiaddr => $ip,
116 Siaddr => $server_ip,
117 Giaddr => $dhcp->giaddr(),
118 Chaddr => $dhcp->chaddr(),
119 File => $file,
120 # DHO_DHCP_MESSAGE_TYPE() => DHCPACK(),
121 # DHO_SUBNET_MASK() => '255.255.255.0',
122 };
123
124 my $messagetype = $dhcp->getOptionValue(DHO_DHCP_MESSAGE_TYPE());
125
126 if ($messagetype eq DHCPDISCOVER()) {
127 warn "DHCP DISCOVER";
128 $packet->{Comment} = $dhcp->comment();
129 $packet->{DHO_DHCP_MESSAGE_TYPE()} = DHCPOFFER();
130 } elsif ($messagetype eq DHCPREQUEST()) {
131 my $requested_ip = $dhcp->getOptionValue(DHO_DHCP_REQUESTED_ADDRESS());
132 warn "DHCP REQUEST $requested_ip";
133 if ( $ip eq $requested_ip ) {
134 $packet->{DHO_DHCP_MESSAGE_TYPE()} = DHCPACK();
135 $packet->{DHO_DHCP_LEASE_TIME()} = 100;
136 } else {
137 $packet->{DHO_DHCP_MESSAGE_TYPE()} = DHCPNAK();
138 $packet->{DHO_DHCP_MESSAGE()} = "Bad request, expected $ip";
139 }
140 } elsif ($messagetype eq DHCPINFORM()) {
141 warn "DHCP INFORM ignored";
142 } else {
143 warn "$messagetype igored (bootp?)";
144 }
145
146
147 warn ">> $mac == $ip server: $server_ip", $file ? " file: $file\n" : "\n";
148
149 $packet = new Net::DHCP::Packet( %$packet );
150 warn "## ",$packet->toString(),"\n" if $debug;
151
152 my $reply = IO::Socket::INET->new(
153 LocalAddr => $server_ip,
154 LocalPort => 67,
155 Proto => "udp",
156 Broadcast => 1,
157 PeerAddr => '255.255.255.255',
158 PeerPort => 68,
159 Reuse => 1,
160 ) or die "socket: $@";
161
162 my $buff = $packet->serialize();
163 $reply->send( $buff, 0 ) or die "Error sending: $!\n";
164
165 # system("arp -s $ip $mac"),
166
167 } else {
168 print "No bootp request.\n";
169 }
170
171 }

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