/[pxelator]/lib/PXElator/dhcpd.pm
This is repository of my old source code which isn't updated any more. Go to git.rot13.org for current projects!
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Annotation of /lib/PXElator/dhcpd.pm

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Revision 36 - (hide annotations)
Wed Jul 29 13:03:39 2009 UTC (14 years, 8 months ago) by dpavlin
Original Path: bin/dhcpd.pl
File MIME type: text/plain
File size: 4191 byte(s)
check if IP is available using Net::Ping

1 dpavlin 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 dpavlin 22 use autodie;
9    
10 dpavlin 1 use IO::Socket::INET;
11 dpavlin 17 use File::Slurp;
12 dpavlin 1 use Data::Dump qw/dump/;
13 dpavlin 36 use Net::Ping;
14 dpavlin 1
15 dpavlin 27 use lib 'lib';
16     use Net::DHCP::Packet;
17     use Net::DHCP::Constants 0.67;
18 dpavlin 1 die "need to run $0 as root like this\nsudo $0\n" unless $< == 0;
19    
20     my $debug = shift @ARGV;
21    
22 dpavlin 22 our ( $file, $gpxe_file );
23 dpavlin 17 our ( $ip_from, $ip_to ) = ( 10, 100 );
24 dpavlin 1
25 dpavlin 22 our $server_ip = readlink 'conf/server.ip' if -l 'conf/server.ip';
26 dpavlin 17
27 dpavlin 22 if ( ! $server_ip ) {
28     $server_ip = `/sbin/ifconfig`;
29     $server_ip =~ s/^.+?addr:([\d\.]+).*$/$1/gs;
30     warn "auto-configure server ip to $server_ip\n";
31     } else {
32     warn "server ip $server_ip\n";
33     }
34    
35 dpavlin 1 my $sock = IO::Socket::INET->new(
36     LocalPort => 67,
37     # LocalAddr => 'localhost',
38     # LocalAddr => '10.0.0.100',
39     LocalAddr => '0.0.0.0',
40     Proto => 'udp',
41     ReuseAddr => 1,
42     # PeerPort => getservbyname('bootpc', 'udp'),
43     Broadcast => 1,
44     Type => SOCK_DGRAM,
45     ) or die "Failed to bind to socket: $@";
46    
47    
48 dpavlin 17 my $addr = $ip_from;
49    
50 dpavlin 1 sub client_ip {
51     my ( $mac ) = @_;
52    
53 dpavlin 17 my $conf = "conf/$server_ip";
54     mkdir $conf unless -e $conf;
55 dpavlin 1
56 dpavlin 22 if ( -e "$conf/mac/$mac" ) {
57     my $ip = read_file "$conf/mac/$mac";
58 dpavlin 17 print "$mac old $ip\n";
59     return $ip;
60     }
61 dpavlin 1
62 dpavlin 17 mkdir $_ foreach grep { ! -e $_ } map { "$conf/$_" } ( 'ip', 'mac' );
63    
64 dpavlin 36 my $p = Net::Ping->new;
65    
66 dpavlin 17 my $prefix = $server_ip;
67     $prefix =~ s{\.\d+$}{.};
68     my $ip = $prefix . $addr;
69 dpavlin 36 while ( -e "conf/ip/$ip" || $p->ping( $ip ) ) {
70 dpavlin 17 $ip = $prefix . $addr++;
71     die "all addresses allocated!" if $addr == $ip_to;
72 dpavlin 1 }
73    
74 dpavlin 17 write_file "$conf/mac/$mac", $ip;
75 dpavlin 33 if ( -l "$conf/ip/$ip" && readlink "$conf/ip/$ip" ne "$conf/mac/$mac") {
76     unlink "$conf/ip/$ip";
77     symlink "$conf/mac/$mac", "$conf/ip/$ip";
78     warn "$mac IP changed to $ip";
79     }
80 dpavlin 17
81     print "$mac NEW $ip\n";
82    
83 dpavlin 1 return $ip;
84     }
85    
86 dpavlin 27 my $transaction = 0; # FIXME predictible transaction numbers
87    
88 dpavlin 1 while (1) {
89    
90 dpavlin 12 require "config.pl"; # refresh config
91    
92 dpavlin 1 print "waiting for DHCP requests on ",$sock->sockhost,":",$sock->sockport,"\n";
93    
94     my $buf;
95     $sock->recv($buf, 1024);
96 dpavlin 17 print "<< ",$sock->peerhost,":",$sock->peerport,"\n";
97 dpavlin 1
98     if (defined $buf) {
99    
100 dpavlin 27 my $dhcp = Net::DHCP::Packet->new($buf);
101     $dhcp->comment( $transaction++ );
102 dpavlin 1
103 dpavlin 27 warn "recv: ", $dhcp->toString, "\n\n";
104 dpavlin 1
105     my $mac = substr($dhcp->chaddr(),0,$dhcp->hlen()*2);
106     my $ip = client_ip($mac);
107 dpavlin 22 my $user_class = $dhcp->getOptionValue(DHO_USER_CLASS());
108 dpavlin 1
109 dpavlin 22 if ( $user_class eq 'gPXE' ) {
110     $file = $gpxe_file;
111     } elsif ( ! $file ) {
112     $file = 'undionly.kpxe';
113 dpavlin 12 }
114 dpavlin 6
115 dpavlin 27 my $packet = {
116 dpavlin 1 Op => BOOTREPLY(),
117     Hops => $dhcp->hops(),
118     Xid => $dhcp->xid(),
119     Flags => $dhcp->flags(),
120     Ciaddr => $dhcp->ciaddr(),
121     Yiaddr => $ip,
122 dpavlin 3 Siaddr => $server_ip,
123 dpavlin 1 Giaddr => $dhcp->giaddr(),
124     Chaddr => $dhcp->chaddr(),
125 dpavlin 6 File => $file,
126 dpavlin 1 # DHO_DHCP_MESSAGE_TYPE() => DHCPACK(),
127 dpavlin 27 # DHO_SUBNET_MASK() => '255.255.255.0',
128     };
129 dpavlin 1
130 dpavlin 27 my $messagetype = $dhcp->getOptionValue(DHO_DHCP_MESSAGE_TYPE());
131 dpavlin 22
132 dpavlin 27 if ($messagetype eq DHCPDISCOVER()) {
133     warn "DHCP DISCOVER";
134     $packet->{Comment} = $dhcp->comment();
135     $packet->{DHO_DHCP_MESSAGE_TYPE()} = DHCPOFFER();
136     } elsif ($messagetype eq DHCPREQUEST()) {
137     my $requested_ip = $dhcp->getOptionValue(DHO_DHCP_REQUESTED_ADDRESS());
138     warn "DHCP REQUEST $requested_ip";
139     if ( $ip eq $requested_ip ) {
140     $packet->{DHO_DHCP_MESSAGE_TYPE()} = DHCPACK();
141 dpavlin 28 $packet->{DHO_DHCP_LEASE_TIME()} = 100;
142 dpavlin 27 } else {
143     $packet->{DHO_DHCP_MESSAGE_TYPE()} = DHCPNAK();
144     $packet->{DHO_DHCP_MESSAGE()} = "Bad request, expected $ip";
145     }
146     } elsif ($messagetype eq DHCPINFORM()) {
147     warn "DHCP INFORM ignored";
148     } else {
149     warn "$messagetype igored (bootp?)";
150     }
151    
152    
153     warn ">> $mac == $ip server: $server_ip", $file ? " file: $file\n" : "\n";
154    
155     $packet = new Net::DHCP::Packet( %$packet );
156 dpavlin 1 warn "## ",$packet->toString(),"\n" if $debug;
157    
158     my $reply = IO::Socket::INET->new(
159 dpavlin 3 LocalAddr => $server_ip,
160 dpavlin 1 LocalPort => 67,
161     Proto => "udp",
162     Broadcast => 1,
163     PeerAddr => '255.255.255.255',
164     PeerPort => 68,
165     Reuse => 1,
166     ) or die "socket: $@";
167    
168     my $buff = $packet->serialize();
169     $reply->send( $buff, 0 ) or die "Error sending: $!\n";
170    
171     # system("arp -s $ip $mac"),
172    
173     } else {
174     print "No bootp request.\n";
175     }
176    
177     }

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