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dpavlin |
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#!/usr/bin/perl |
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# based on http://www.perlmonks.org/index.pl?node_id=325248 |
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use strict; |
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use warnings; |
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use IO::Socket::INET; |
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use Net::DHCP::Packet; |
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use Net::DHCP::Constants; |
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use File::Slurp; |
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use Data::Dump qw/dump/; |
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die "need to run $0 as root like this\nsudo $0\n" unless $< == 0; |
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my $debug = shift @ARGV; |
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our ( $file, $next_file ); |
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our ( $ip_from, $ip_to ) = ( 10, 100 ); |
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our $server_ip = readlink 'conf/server.ip'; |
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my $sock = IO::Socket::INET->new( |
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LocalPort => 67, |
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# LocalAddr => 'localhost', |
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# LocalAddr => '10.0.0.100', |
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LocalAddr => '0.0.0.0', |
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Proto => 'udp', |
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ReuseAddr => 1, |
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# PeerPort => getservbyname('bootpc', 'udp'), |
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Broadcast => 1, |
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Type => SOCK_DGRAM, |
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) or die "Failed to bind to socket: $@"; |
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my $addr = $ip_from; |
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sub client_ip { |
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my ( $mac ) = @_; |
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my $conf = "conf/$server_ip"; |
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mkdir $conf unless -e $conf; |
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if ( -e "$conf/$mac" ) { |
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my $ip = read_file "conf/mac/$mac"; |
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print "$mac old $ip\n"; |
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return $ip; |
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} |
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mkdir $_ foreach grep { ! -e $_ } map { "$conf/$_" } ( 'ip', 'mac' ); |
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my $prefix = $server_ip; |
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$prefix =~ s{\.\d+$}{.}; |
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my $ip = $prefix . $addr; |
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while ( -e "conf/ip/$ip" ) { |
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$ip = $prefix . $addr++; |
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die "all addresses allocated!" if $addr == $ip_to; |
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} |
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write_file "$conf/mac/$mac", $ip; |
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symlink "$conf/mac/$mac", "conf/ip/$ip"; |
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print "$mac NEW $ip\n"; |
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return $ip; |
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} |
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while (1) { |
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require "config.pl"; # refresh config |
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print "waiting for DHCP requests on ",$sock->sockhost,":",$sock->sockport,"\n"; |
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my $buf; |
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$sock->recv($buf, 1024); |
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print "<< ",$sock->peerhost,":",$sock->peerport,"\n"; |
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if (defined $buf) { |
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my $dhcp; |
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eval { $dhcp = Net::DHCP::Packet->new($buf); }; |
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die "can't use request", dump( $buf ) if $@; |
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if ( $debug ) { |
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warn "recv: ", $dhcp->toString, "\n\n"; |
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} |
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my $mac = substr($dhcp->chaddr(),0,$dhcp->hlen()*2); |
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my $ip = client_ip($mac); |
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if ( ! $file ) { |
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if ( $dhcp->getOptionValue(DHO_USER_CLASS()) ne 'gPXE' ) { |
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$file = 'undionly.kpxe'; |
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} else { |
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$file = $next_file; |
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} |
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} |
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my $packet = new Net::DHCP::Packet( |
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Op => BOOTREPLY(), |
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Hops => $dhcp->hops(), |
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Xid => $dhcp->xid(), |
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Flags => $dhcp->flags(), |
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Ciaddr => $dhcp->ciaddr(), |
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Yiaddr => $ip, |
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Siaddr => $server_ip, |
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Giaddr => $dhcp->giaddr(), |
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Chaddr => $dhcp->chaddr(), |
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File => $file, |
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# DHO_DHCP_MESSAGE_TYPE() => DHCPACK(), |
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DHO_SUBNET_MASK() => '255.0.0.0', |
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); |
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warn ">> $mac == $ip server $server_ip\n"; |
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warn "## ",$packet->toString(),"\n" if $debug; |
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my $reply = IO::Socket::INET->new( |
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LocalAddr => $server_ip, |
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LocalPort => 67, |
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Proto => "udp", |
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Broadcast => 1, |
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PeerAddr => '255.255.255.255', |
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PeerPort => 68, |
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Reuse => 1, |
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) or die "socket: $@"; |
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my $buff = $packet->serialize(); |
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$reply->send( $buff, 0 ) or die "Error sending: $!\n"; |
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# system("arp -s $ip $mac"), |
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} else { |
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print "No bootp request.\n"; |
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} |
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} |