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#!/usr/bin/perl |
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|
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# based on http://www.perlmonks.org/index.pl?node_id=325248 |
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|
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use strict; |
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use warnings; |
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|
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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 Data::Dump qw/dump/; |
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|
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die "need to run $0 as root like this\nsudo $0\n" unless $< == 0; |
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|
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my $debug = shift @ARGV; |
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|
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my $ip_server = '10.0.0.100'; |
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|
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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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|
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my $_ip = 10; |
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my $_mac2ip; |
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|
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sub client_ip { |
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my ( $mac ) = @_; |
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|
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my $ip = $_mac2ip->{$mac}; |
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return $ip if $ip; |
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|
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$ip = "10.0.0.$_ip"; |
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$_mac2ip->{$mac} = $ip; |
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|
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$_ip++; |
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if ( $_ip == 100 ) { |
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warn "IP roll-over to 10\n"; |
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$_ip = 10; |
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} |
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|
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return $ip; |
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} |
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|
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while (1) { |
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|
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print "waiting for DHCP requests on ",$sock->sockhost,":",$sock->sockport,"\n"; |
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|
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my $buf; |
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$sock->recv($buf, 1024); |
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print "<< peer:",$sock->peerhost,":",$sock->peerport,"\n"; |
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|
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if (defined $buf) { |
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|
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my $dhcp; |
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|
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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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|
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if ( $debug ) { |
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warn "recv: ", $dhcp->toString, "\n\n"; |
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} |
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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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|
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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 => $ip_server, |
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Giaddr => $dhcp->giaddr(), |
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Chaddr => $dhcp->chaddr(), |
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File => 'undionly.kpxe', |
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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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|
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warn ">> $mac == $ip server $ip_server\n"; |
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|
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warn "## ",$packet->toString(),"\n" if $debug; |
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|
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my $reply = IO::Socket::INET->new( |
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LocalAddr => $ip_server, |
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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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|
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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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|
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# system("arp -s $ip $mac"), |
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|
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} else { |
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print "No bootp request.\n"; |
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} |
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|
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} |