#!/usr/bin/perl
# Simple DHCP client - sending a broadcasted DHCP Discover request

use strict;
use warnings;
use IO::Socket::IP -register;

use Net::DHCP::Packet;
use Net::DHCP::Constants;

use POSIX qw(setsid strftime);

my ($request, $send, $receive, $discover, $response, $buf, $serverip, $myip, $mymac, $hostname);

$mymac = qx/ \/sbin\/ifconfig | grep -P '^eth0.+HWaddr\\s*' | awk '{print \$5}' /;
$mymac =~ tr/://d;
chomp($hostname = `hostname -s`);
# Overrule when testing
#$mymac = '001cc0c33317';
logger("mac: $mymac");

# sample logger
sub logger{
    my $str = shift;
    print STDOUT strftime "[%d/%b/%Y:%H:%M:%S] ", localtime;
    print STDOUT "$str\n";
}

logger("DHCPd tester - dummy client");

logger("Opening socket");
$send = IO::Socket::IP->new(  Proto => 'udp',
                                Broadcast => 1,
                                PeerPort => 'bootps(67)',
                                #PeerAddr => inet_ntoa(INADDR_LOOPBACK),#(INADDR_BROADCAST),
                                PeerAddr => inet_ntoa(INADDR_BROADCAST),
                                )
      || die "Socket (send) creation error: $@\n";     # yes, it uses $@ here

# create DHCP Packet DISCOVER
my $xid = int(rand(0xFFFFFFFF));
$discover = Net::DHCP::Packet->new(
			  Chaddr => $mymac,
			  Giaddr => $send->sockhost(),
              Xid => $xid, # random xid
              DHO_DHCP_MESSAGE_TYPE() => DHCPDISCOVER(),
              Flags => 0x8000,
			  DHO_VENDOR_CLASS_IDENTIFIER() => 'foo',
			  DHO_HOST_NAME() => $hostname,
              );

logger("Sending DISCOVER to " . $send->peerhost . ":" . $send->peerport);
logger($discover->toString());
$send->send($discover->serialize(), 0)
              or die "Error sending:$!\n";

$receive = IO::Socket::IP->new(  Proto => 'udp',
                                Broadcast => 1,
                                LocalPort => 'bootpc(68)',
                                #LocalAddr => inet_ntoa(INADDR_LOOPBACK),#(INADDR_ANY),
                                LocalAddr => inet_ntoa(INADDR_ANY),
                                )
      || die "Socket (receive) creation error: $@\n";     # yes, it uses $@ here

logger("Listen: " . $receive->sockhost . ":" . $receive->sockport);
logger("Waiting for response from server");
$receive->recv($buf, 1024, 0);
logger("Got response from " . $receive->peerhost . ":" . $receive->peerport);
$receive->close;
$response = new Net::DHCP::Packet($buf);
if ($response->getOptionValue(DHO_DHCP_MESSAGE_TYPE()) == DHCPNAK()) {
	logger("Request for ip was denied");
	exit;
}

$serverip = $response->getOptionValue(DHO_DHCP_SERVER_IDENTIFIER());
$myip = $response->yiaddr();

logger($response->toString());

# create DHCP Packet REQUEST
$request = Net::DHCP::Packet->new(
                      Xid => $xid, # random xid
                      Chaddr => $mymac,
                      Giaddr => $send->sockhost(),
                      DHO_DHCP_MESSAGE_TYPE() => DHCPREQUEST(),
					  DHO_VENDOR_CLASS_IDENTIFIER() => 'foo',
					  DHO_HOST_NAME() => $hostname,
                      DHO_DHCP_REQUESTED_ADDRESS() => $myip,
                      );

logger("Sending REQUEST to " . $send->peerhost . ":" . $send->peerport);
logger($request->toString());

$send->send($request->serialize())
              or die "Error sending:$!\n";
$send->close;

$receive = IO::Socket::IP->new(  Proto => 'udp',
                                Broadcast => 1,
                                LocalPort => 'bootpc(68)',
                                #LocalAddr => inet_ntoa(INADDR_LOOPBACK),#inet_ntoa(INADDR_ANY),
                                LocalAddr => inet_ntoa(INADDR_ANY),
                                )
      || die "Socket creation error: $@\n";     # yes, it uses $@ here

logger("Waiting for response from server");
$receive->recv($buf, 1024, 0);
logger("Got response from " . $receive->peerhost . ":" . $receive->peerport);
$receive->close;
$response = new Net::DHCP::Packet($buf);
logger($response->toString());

if ($response->getOptionValue(DHO_DHCP_MESSAGE_TYPE()) == DHCPACK()) {
	$send = IO::Socket::IP->new(  Proto => 'udp',
								  Broadcast => 1,
								  PeerPort => 'bootps(67)',
								  PeerAddr => $serverip,
								)
		  || die "Socket (send) creation error: $@\n";     # yes, it uses $@ here

	# create DHCP Packet REQUEST
	$request = Net::DHCP::Packet->new(
						  op => BOOTREQUEST(),
						  Xid => int(rand(0xFFFFFFFF)), # random xid
						  Chaddr => $mymac,
						  Ciaddr => $myip,
						  Giaddr => $send->sockhost(),
						  DHO_VENDOR_CLASS_IDENTIFIER() => 'foo',
						  DHO_HOST_NAME() => $hostname,
						  DHO_DHCP_MESSAGE_TYPE() => DHCPRELEASE()
						  );

	logger("Sending REQUEST to " . $send->peerhost . ":" . $send->peerport);
	logger($request->toString());

	$send->send($request->serialize())
				  or die "Error sending:$!\n";
	$send->close;
} else {
	logger("Request for ip $myip was denied")
}