1*00b67f09SDavid van Moolenbroek#!/usr/bin/perl -w
2*00b67f09SDavid van Moolenbroek#
3*00b67f09SDavid van Moolenbroek# Copyright (C) 2012  Internet Systems Consortium, Inc. ("ISC")
4*00b67f09SDavid van Moolenbroek#
5*00b67f09SDavid van Moolenbroek# Permission to use, copy, modify, and/or distribute this software for any
6*00b67f09SDavid van Moolenbroek# purpose with or without fee is hereby granted, provided that the above
7*00b67f09SDavid van Moolenbroek# copyright notice and this permission notice appear in all copies.
8*00b67f09SDavid van Moolenbroek#
9*00b67f09SDavid van Moolenbroek# THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10*00b67f09SDavid van Moolenbroek# REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11*00b67f09SDavid van Moolenbroek# AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12*00b67f09SDavid van Moolenbroek# INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13*00b67f09SDavid van Moolenbroek# LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14*00b67f09SDavid van Moolenbroek# OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15*00b67f09SDavid van Moolenbroek# PERFORMANCE OF THIS SOFTWARE.
16*00b67f09SDavid van Moolenbroek
17*00b67f09SDavid van Moolenbroek# Id
18*00b67f09SDavid van Moolenbroek
19*00b67f09SDavid van Moolenbroek#
20*00b67f09SDavid van Moolenbroek# Ad hoc name server
21*00b67f09SDavid van Moolenbroek#
22*00b67f09SDavid van Moolenbroek
23*00b67f09SDavid van Moolenbroekuse IO::File;
24*00b67f09SDavid van Moolenbroekuse IO::Socket;
25*00b67f09SDavid van Moolenbroekuse Net::DNS;
26*00b67f09SDavid van Moolenbroekuse Net::DNS::Packet;
27*00b67f09SDavid van Moolenbroek
28*00b67f09SDavid van Moolenbroekmy $sock = IO::Socket::INET->new(LocalAddr => "10.53.0.4",
29*00b67f09SDavid van Moolenbroek   LocalPort => 5300, Proto => "udp") or die "$!";
30*00b67f09SDavid van Moolenbroek
31*00b67f09SDavid van Moolenbroekmy $pidf = new IO::File "ans.pid", "w" or die "cannot open pid file: $!";
32*00b67f09SDavid van Moolenbroekprint $pidf "$$\n" or die "cannot write pid file: $!";
33*00b67f09SDavid van Moolenbroek$pidf->close or die "cannot close pid file: $!";
34*00b67f09SDavid van Moolenbroeksub rmpid { unlink "ans.pid"; exit 1; };
35*00b67f09SDavid van Moolenbroek
36*00b67f09SDavid van Moolenbroek$SIG{INT} = \&rmpid;
37*00b67f09SDavid van Moolenbroek$SIG{TERM} = \&rmpid;
38*00b67f09SDavid van Moolenbroek
39*00b67f09SDavid van Moolenbroekfor (;;) {
40*00b67f09SDavid van Moolenbroek	$sock->recv($buf, 512);
41*00b67f09SDavid van Moolenbroek
42*00b67f09SDavid van Moolenbroek	print "**** request from " , $sock->peerhost, " port ", $sock->peerport, "\n";
43*00b67f09SDavid van Moolenbroek
44*00b67f09SDavid van Moolenbroek	my $packet;
45*00b67f09SDavid van Moolenbroek
46*00b67f09SDavid van Moolenbroek	if ($Net::DNS::VERSION > 0.68) {
47*00b67f09SDavid van Moolenbroek		$packet = new Net::DNS::Packet(\$buf, 0);
48*00b67f09SDavid van Moolenbroek		$@ and die $@;
49*00b67f09SDavid van Moolenbroek	} else {
50*00b67f09SDavid van Moolenbroek		my $err;
51*00b67f09SDavid van Moolenbroek		($packet, $err) = new Net::DNS::Packet(\$buf, 0);
52*00b67f09SDavid van Moolenbroek		$err and die $err;
53*00b67f09SDavid van Moolenbroek	}
54*00b67f09SDavid van Moolenbroek
55*00b67f09SDavid van Moolenbroek	print "REQUEST:\n";
56*00b67f09SDavid van Moolenbroek	$packet->print;
57*00b67f09SDavid van Moolenbroek
58*00b67f09SDavid van Moolenbroek	$packet->header->qr(1);
59*00b67f09SDavid van Moolenbroek
60*00b67f09SDavid van Moolenbroek	my @questions = $packet->question;
61*00b67f09SDavid van Moolenbroek	my $qname = $questions[0]->qname;
62*00b67f09SDavid van Moolenbroek	my $qtype = $questions[0]->qtype;
63*00b67f09SDavid van Moolenbroek
64*00b67f09SDavid van Moolenbroek	my $donotrespond = 0;
65*00b67f09SDavid van Moolenbroek
66*00b67f09SDavid van Moolenbroek	if ($qname eq "foo.info") {
67*00b67f09SDavid van Moolenbroek		$donotrespond = 1;
68*00b67f09SDavid van Moolenbroek	} elsif ($qname eq "cname1.example.com") {
69*00b67f09SDavid van Moolenbroek		# Data for the "cname + other data / 1" test
70*00b67f09SDavid van Moolenbroek		$packet->push("answer", new Net::DNS::RR("cname1.example.com 300 CNAME cname1.example.com"));
71*00b67f09SDavid van Moolenbroek		$packet->push("answer", new Net::DNS::RR("cname1.example.com 300 A 1.2.3.4"));
72*00b67f09SDavid van Moolenbroek	} elsif ($qname eq "cname2.example.com") {
73*00b67f09SDavid van Moolenbroek		# Data for the "cname + other data / 2" test: same RRs in opposite order
74*00b67f09SDavid van Moolenbroek		$packet->push("answer", new Net::DNS::RR("cname2.example.com 300 A 1.2.3.4"));
75*00b67f09SDavid van Moolenbroek		$packet->push("answer", new Net::DNS::RR("cname2.example.com 300 CNAME cname2.example.com"));
76*00b67f09SDavid van Moolenbroek	} elsif ($qname eq "www.example.org" || $qname eq "www.example.net" ||
77*00b67f09SDavid van Moolenbroek		 $qname eq "badcname.example.org" ||
78*00b67f09SDavid van Moolenbroek		 $qname eq "goodcname.example.org" ||
79*00b67f09SDavid van Moolenbroek		 $qname eq "foo.baddname.example.org" ||
80*00b67f09SDavid van Moolenbroek		 $qname eq "foo.gooddname.example.org") {
81*00b67f09SDavid van Moolenbroek		# Data for address/alias filtering.
82*00b67f09SDavid van Moolenbroek		$packet->header->aa(1);
83*00b67f09SDavid van Moolenbroek		if ($qtype eq "A") {
84*00b67f09SDavid van Moolenbroek			$packet->push("answer",
85*00b67f09SDavid van Moolenbroek				      new Net::DNS::RR($qname .
86*00b67f09SDavid van Moolenbroek						       " 300 A 192.0.2.1"));
87*00b67f09SDavid van Moolenbroek		} elsif ($qtype eq "AAAA") {
88*00b67f09SDavid van Moolenbroek			$packet->push("answer",
89*00b67f09SDavid van Moolenbroek				      new Net::DNS::RR($qname .
90*00b67f09SDavid van Moolenbroek						" 300 AAAA 2001:db8:beef::1"));
91*00b67f09SDavid van Moolenbroek		}
92*00b67f09SDavid van Moolenbroek	} elsif ($qname eq "badcname.example.net" ||
93*00b67f09SDavid van Moolenbroek		 $qname eq "goodcname.example.net") {
94*00b67f09SDavid van Moolenbroek		# Data for CNAME/DNAME filtering.  We need to make one-level
95*00b67f09SDavid van Moolenbroek		# delegation to avoid automatic acceptance for subdomain aliases
96*00b67f09SDavid van Moolenbroek		$packet->push("authority", new Net::DNS::RR("example.net 300 NS ns.example.net"));
97*00b67f09SDavid van Moolenbroek		$packet->push("additional", new Net::DNS::RR("ns.example.net 300 A 10.53.0.3"));
98*00b67f09SDavid van Moolenbroek	} elsif ($qname =~ /^nodata\.example\.net$/i) {
99*00b67f09SDavid van Moolenbroek		$packet->header->aa(1);
100*00b67f09SDavid van Moolenbroek	} elsif ($qname =~ /^nxdomain\.example\.net$/i) {
101*00b67f09SDavid van Moolenbroek		$packet->header->aa(1);
102*00b67f09SDavid van Moolenbroek		$packet->header->rcode(NXDOMAIN);
103*00b67f09SDavid van Moolenbroek	} elsif ($qname =~ /sub\.example\.org/) {
104*00b67f09SDavid van Moolenbroek		# Data for CNAME/DNAME filtering.  The final answers are
105*00b67f09SDavid van Moolenbroek		# expected to be accepted regardless of the filter setting.
106*00b67f09SDavid van Moolenbroek		$packet->push("authority", new Net::DNS::RR("sub.example.org 300 NS ns.sub.example.org"));
107*00b67f09SDavid van Moolenbroek		$packet->push("additional", new Net::DNS::RR("ns.sub.example.org 300 A 10.53.0.3"));
108*00b67f09SDavid van Moolenbroek	} else {
109*00b67f09SDavid van Moolenbroek		# Data for the "bogus referrals" test
110*00b67f09SDavid van Moolenbroek		$packet->push("authority", new Net::DNS::RR("below.www.example.com 300 NS ns.below.www.example.com"));
111*00b67f09SDavid van Moolenbroek		$packet->push("additional", new Net::DNS::RR("ns.below.www.example.com 300 A 10.53.0.3"));
112*00b67f09SDavid van Moolenbroek	}
113*00b67f09SDavid van Moolenbroek
114*00b67f09SDavid van Moolenbroek	if ($donotrespond == 0) {
115*00b67f09SDavid van Moolenbroek		$sock->send($packet->data);
116*00b67f09SDavid van Moolenbroek		print "RESPONSE:\n";
117*00b67f09SDavid van Moolenbroek		$packet->print;
118*00b67f09SDavid van Moolenbroek		print "\n";
119*00b67f09SDavid van Moolenbroek	}
120*00b67f09SDavid van Moolenbroek}
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