#!/usr/bin/perl

#

# Copyright (C) Internet Systems Consortium, Inc. ("ISC")

#

# This Source Code Form is subject to the terms of the Mozilla Public

# License, v. 2.0. If a copy of the MPL was not distributed with this

# file, You can obtain one at http://mozilla.org/MPL/2.0/.

#

# See the COPYRIGHT file distributed with this work for additional

# information regarding copyright ownership.

#

# Ad hoc name server

#

use IO::File;

use IO::Socket;

use Net::DNS;

use Net::DNS::Packet;

my $localport = int($ENV{'PORT'});

if (!$localport) { $localport = 5300; }

my $sock = IO::Socket::INET->new(LocalAddr => "10.53.0.2",

   LocalPort => $localport, Proto => "udp") or die "$!";

my $pidf = new IO::File "ans.pid", "w" or die "cannot open pid file: $!";

print $pidf "$$\n" or die "cannot write pid file: $!";

$pidf->close or die "cannot close pid file: $!";

sub rmpid { unlink "ans.pid"; exit 1; };

$SIG{INT} = \&rmpid;

$SIG{TERM} = \&rmpid;

for (;;) {

	$sock->recv($buf, 512);

	print "**** request from " , $sock->peerhost, " port ", $sock->peerport, "\n";

	my $packet;

	if ($Net::DNS::VERSION > 0.68) {

		$packet = new Net::DNS::Packet(\$buf, 0);

		$@ and die $@;

	} else {

		my $err;

		($packet, $err) = new Net::DNS::Packet(\$buf, 0);

		$err and die $err;

	}

	print "REQUEST:\n";

	$packet->print;

	$packet->header->qr(1);

	my @questions = $packet->question;

	my $qname = $questions[0]->qname;

	my $qtype = $questions[0]->qtype;

	if ($qname eq "cname1.example.com") {

		# Data for the "cname + other data / 1" test

		$packet->push("answer", new Net::DNS::RR("cname1.example.com 300 CNAME cname1.example.com"));

		$packet->push("answer", new Net::DNS::RR("cname1.example.com 300 A 1.2.3.4"));

	} elsif ($qname eq "cname2.example.com") {

		# Data for the "cname + other data / 2" test: same RRs in opposite order

		$packet->push("answer", new Net::DNS::RR("cname2.example.com 300 A 1.2.3.4"));

		$packet->push("answer", new Net::DNS::RR("cname2.example.com 300 CNAME cname2.example.com"));

	} elsif ($qname eq "www.example.org" || $qname eq "www.example.net" ||

		 $qname eq "badcname.example.org" ||

		 $qname eq "goodcname.example.org" ||

		 $qname eq "foo.baddname.example.org" ||

		 $qname eq "foo.gooddname.example.org") {

		# Data for address/alias filtering.

		$packet->header->aa(1);

		if ($qtype eq "A") {

			$packet->push("answer",

				      new Net::DNS::RR($qname .

						       " 300 A 192.0.2.1"));

		} elsif ($qtype eq "AAAA") {

			$packet->push("answer",

				      new Net::DNS::RR($qname .

						" 300 AAAA 2001:db8:beef::1"));

		}

	} elsif ($qname eq "badcname.example.net" ||

		 $qname eq "goodcname.example.net") {

		# Data for CNAME/DNAME filtering.  We need to make one-level

		# delegation to avoid automatic acceptance for subdomain aliases

		$packet->push("authority", new Net::DNS::RR("example.net 300 NS ns.example.net"));

		$packet->push("additional", new Net::DNS::RR("ns.example.net 300 A 10.53.0.3"));

	} elsif ($qname =~ /^nodata\.example\.net$/i) {

		$packet->header->aa(1);

	} elsif ($qname =~ /^nxdomain\.example\.net$/i) {

		$packet->header->aa(1);

		$packet->header->rcode(NXDOMAIN);

	} elsif ($qname =~ /sub\.example\.org/) {

		# Data for CNAME/DNAME filtering.  The final answers are

		# expected to be accepted regardless of the filter setting.

		$packet->push("authority", new Net::DNS::RR("sub.example.org 300 NS ns.sub.example.org"));

		$packet->push("additional", new Net::DNS::RR("ns.sub.example.org 300 A 10.53.0.3"));

	} elsif ($qname =~ /\.broken/) {

		# Delegation to broken TLD.

		$packet->push("authority", new Net::DNS::RR("broken 300 NS ns.broken"));

		$packet->push("additional", new Net::DNS::RR("ns.broken 300 A 10.53.0.4"));

	} else {

		# Data for the "bogus referrals" test

		$packet->push("authority", new Net::DNS::RR("below.www.example.com 300 NS ns.below.www.example.com"));

		$packet->push("additional", new Net::DNS::RR("ns.below.www.example.com 300 A 10.53.0.3"));

	}

	$sock->send($packet->data);

	print "RESPONSE:\n";

	$packet->print;

	print "\n";

}