1#!/usr/bin/perl
2#
3# Copyright (C) 2004, 2007, 2009, 2012  Internet Systems Consortium, Inc. ("ISC")
4# Copyright (C) 2000, 2001  Internet Software Consortium.
5#
6# Permission to use, copy, modify, and/or distribute this software for any
7# purpose with or without fee is hereby granted, provided that the above
8# copyright notice and this permission notice appear in all copies.
9#
10# THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
11# REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
12# AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
13# INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
14# LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
15# OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
16# PERFORMANCE OF THIS SOFTWARE.
17
18# Id: ans.pl,v 1.12 2009/11/04 02:15:30 marka Exp
19
20#
21# Ad hoc name server
22#
23
24use IO::File;
25use IO::Socket;
26use Net::DNS;
27use Net::DNS::Packet;
28
29my $sock = IO::Socket::INET->new(LocalAddr => "10.53.0.3",
30   LocalPort => 5300, Proto => "udp") or die "$!";
31
32my $pidf = new IO::File "ans.pid", "w" or die "cannot open pid file: $!";
33print $pidf "$$\n" or die "cannot write pid file: $!";
34$pidf->close or die "cannot close pid file: $!";
35sub rmpid { unlink "ans.pid"; exit 1; };
36
37$SIG{INT} = \&rmpid;
38$SIG{TERM} = \&rmpid;
39
40for (;;) {
41	$sock->recv($buf, 512);
42
43	print "**** request from " , $sock->peerhost, " port ", $sock->peerport, "\n";
44
45	my $packet;
46
47	if ($Net::DNS::VERSION > 0.68) {
48		$packet = new Net::DNS::Packet(\$buf, 0);
49		$@ and die $@;
50	} else {
51		my $err;
52		($packet, $err) = new Net::DNS::Packet(\$buf, 0);
53		$err and die $err;
54	}
55
56	print "REQUEST:\n";
57	$packet->print;
58
59	$packet->header->qr(1);
60	$packet->header->aa(1);
61
62	my @questions = $packet->question;
63	my $qname = $questions[0]->qname;
64
65	if ($qname eq "badcname.example.net") {
66		$packet->push("answer",
67			      new Net::DNS::RR($qname .
68				       " 300 CNAME badcname.example.org"));
69	} elsif ($qname eq "foo.baddname.example.net") {
70		$packet->push("answer",
71			      new Net::DNS::RR("baddname.example.net" .
72				       " 300 DNAME baddname.example.org"));
73	} elsif ($qname eq "foo.gooddname.example.net") {
74		$packet->push("answer",
75			      new Net::DNS::RR("gooddname.example.net" .
76				       " 300 DNAME gooddname.example.org"));
77	} elsif ($qname eq "goodcname.example.net") {
78		$packet->push("answer",
79			      new Net::DNS::RR($qname .
80				       " 300 CNAME goodcname.example.org"));
81	} elsif ($qname eq "cname.sub.example.org") {
82		$packet->push("answer",
83			      new Net::DNS::RR($qname .
84				       " 300 CNAME ok.sub.example.org"));
85	} elsif ($qname eq "ok.sub.example.org") {
86		$packet->push("answer",
87			      new Net::DNS::RR($qname . " 300 A 192.0.2.1"));
88	} elsif ($qname eq "www.dname.sub.example.org") {
89		$packet->push("answer",
90			      new Net::DNS::RR("dname.sub.example.org" .
91				       " 300 DNAME ok.sub.example.org"));
92	} elsif ($qname eq "www.ok.sub.example.org") {
93		$packet->push("answer",
94			      new Net::DNS::RR($qname . " 300 A 192.0.2.1"));
95	} else {
96		$packet->push("answer", new Net::DNS::RR("www.example.com 300 A 1.2.3.4"));
97	}
98
99	$sock->send($packet->data);
100
101	print "RESPONSE:\n";
102	$packet->print;
103	print "\n";
104}
105