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 Net::DHCP::Packet; |
12 |
use Net::DHCP::Constants; |
13 |
use File::Slurp; |
14 |
use Data::Dump qw/dump/; |
15 |
|
16 |
die "need to run $0 as root like this\nsudo $0\n" unless $< == 0; |
17 |
|
18 |
my $debug = shift @ARGV; |
19 |
|
20 |
our ( $file, $gpxe_file ); |
21 |
our ( $ip_from, $ip_to ) = ( 10, 100 ); |
22 |
|
23 |
our $server_ip = readlink 'conf/server.ip' if -l 'conf/server.ip'; |
24 |
|
25 |
if ( ! $server_ip ) { |
26 |
$server_ip = `/sbin/ifconfig`; |
27 |
$server_ip =~ s/^.+?addr:([\d\.]+).*$/$1/gs; |
28 |
warn "auto-configure server ip to $server_ip\n"; |
29 |
} else { |
30 |
warn "server ip $server_ip\n"; |
31 |
} |
32 |
|
33 |
my $sock = IO::Socket::INET->new( |
34 |
LocalPort => 67, |
35 |
# LocalAddr => 'localhost', |
36 |
# LocalAddr => '10.0.0.100', |
37 |
LocalAddr => '0.0.0.0', |
38 |
Proto => 'udp', |
39 |
ReuseAddr => 1, |
40 |
# PeerPort => getservbyname('bootpc', 'udp'), |
41 |
Broadcast => 1, |
42 |
Type => SOCK_DGRAM, |
43 |
) or die "Failed to bind to socket: $@"; |
44 |
|
45 |
|
46 |
my $addr = $ip_from; |
47 |
|
48 |
sub client_ip { |
49 |
my ( $mac ) = @_; |
50 |
|
51 |
my $conf = "conf/$server_ip"; |
52 |
mkdir $conf unless -e $conf; |
53 |
|
54 |
if ( -e "$conf/mac/$mac" ) { |
55 |
my $ip = read_file "$conf/mac/$mac"; |
56 |
print "$mac old $ip\n"; |
57 |
return $ip; |
58 |
} |
59 |
|
60 |
mkdir $_ foreach grep { ! -e $_ } map { "$conf/$_" } ( 'ip', 'mac' ); |
61 |
|
62 |
my $prefix = $server_ip; |
63 |
$prefix =~ s{\.\d+$}{.}; |
64 |
my $ip = $prefix . $addr; |
65 |
while ( -e "conf/ip/$ip" ) { |
66 |
$ip = $prefix . $addr++; |
67 |
die "all addresses allocated!" if $addr == $ip_to; |
68 |
} |
69 |
|
70 |
write_file "$conf/mac/$mac", $ip; |
71 |
unlink "$conf/ip/$ip" if -e "$conf/ip/$ip"; |
72 |
symlink "$conf/mac/$mac", "$conf/ip/$ip"; |
73 |
|
74 |
print "$mac NEW $ip\n"; |
75 |
|
76 |
return $ip; |
77 |
} |
78 |
|
79 |
while (1) { |
80 |
|
81 |
require "config.pl"; # refresh config |
82 |
|
83 |
print "waiting for DHCP requests on ",$sock->sockhost,":",$sock->sockport,"\n"; |
84 |
|
85 |
my $buf; |
86 |
$sock->recv($buf, 1024); |
87 |
print "<< ",$sock->peerhost,":",$sock->peerport,"\n"; |
88 |
|
89 |
if (defined $buf) { |
90 |
|
91 |
my $dhcp; |
92 |
|
93 |
eval { $dhcp = Net::DHCP::Packet->new($buf); }; |
94 |
die "can't use request", dump( $buf ) if $@; |
95 |
|
96 |
if ( $debug ) { |
97 |
warn "recv: ", $dhcp->toString, "\n\n"; |
98 |
} |
99 |
|
100 |
my $mac = substr($dhcp->chaddr(),0,$dhcp->hlen()*2); |
101 |
my $ip = client_ip($mac); |
102 |
my $user_class = $dhcp->getOptionValue(DHO_USER_CLASS()); |
103 |
|
104 |
if ( $user_class eq 'gPXE' ) { |
105 |
$file = $gpxe_file; |
106 |
} elsif ( ! $file ) { |
107 |
$file = 'undionly.kpxe'; |
108 |
} |
109 |
|
110 |
my $packet = new Net::DHCP::Packet( |
111 |
Op => BOOTREPLY(), |
112 |
Hops => $dhcp->hops(), |
113 |
Xid => $dhcp->xid(), |
114 |
Flags => $dhcp->flags(), |
115 |
Ciaddr => $dhcp->ciaddr(), |
116 |
Yiaddr => $ip, |
117 |
Siaddr => $server_ip, |
118 |
Giaddr => $dhcp->giaddr(), |
119 |
Chaddr => $dhcp->chaddr(), |
120 |
File => $file, |
121 |
# DHO_DHCP_MESSAGE_TYPE() => DHCPACK(), |
122 |
DHO_SUBNET_MASK() => '255.0.0.0', |
123 |
); |
124 |
|
125 |
warn ">> $mac == $ip server: $server_ip file: $file\n"; |
126 |
|
127 |
warn "## ",$packet->toString(),"\n" if $debug; |
128 |
|
129 |
my $reply = IO::Socket::INET->new( |
130 |
LocalAddr => $server_ip, |
131 |
LocalPort => 67, |
132 |
Proto => "udp", |
133 |
Broadcast => 1, |
134 |
PeerAddr => '255.255.255.255', |
135 |
PeerPort => 68, |
136 |
Reuse => 1, |
137 |
) or die "socket: $@"; |
138 |
|
139 |
my $buff = $packet->serialize(); |
140 |
$reply->send( $buff, 0 ) or die "Error sending: $!\n"; |
141 |
|
142 |
# system("arp -s $ip $mac"), |
143 |
|
144 |
} else { |
145 |
print "No bootp request.\n"; |
146 |
} |
147 |
|
148 |
} |