1#!/usr/bin/perl -w 2# 3# Copyright (C) 2012 Internet Systems Consortium, Inc. ("ISC") 4# 5# Permission to use, copy, modify, and/or distribute this software for any 6# purpose with or without fee is hereby granted, provided that the above 7# copyright notice and this permission notice appear in all copies. 8# 9# THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH 10# REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY 11# AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, 12# INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 13# LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE 14# OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 15# PERFORMANCE OF THIS SOFTWARE. 16 17# Id 18 19# 20# Ad hoc name server 21# 22 23use IO::File; 24use IO::Socket; 25use Net::DNS; 26use Net::DNS::Packet; 27 28my $sock = IO::Socket::INET->new(LocalAddr => "10.53.0.4", 29 LocalPort => 5300, Proto => "udp") or die "$!"; 30 31my $pidf = new IO::File "ans.pid", "w" or die "cannot open pid file: $!"; 32print $pidf "$$\n" or die "cannot write pid file: $!"; 33$pidf->close or die "cannot close pid file: $!"; 34sub rmpid { unlink "ans.pid"; exit 1; }; 35 36$SIG{INT} = \&rmpid; 37$SIG{TERM} = \&rmpid; 38 39for (;;) { 40 $sock->recv($buf, 512); 41 42 print "**** request from " , $sock->peerhost, " port ", $sock->peerport, "\n"; 43 44 my $packet; 45 46 if ($Net::DNS::VERSION > 0.68) { 47 $packet = new Net::DNS::Packet(\$buf, 0); 48 $@ and die $@; 49 } else { 50 my $err; 51 ($packet, $err) = new Net::DNS::Packet(\$buf, 0); 52 $err and die $err; 53 } 54 55 print "REQUEST:\n"; 56 $packet->print; 57 58 $packet->header->qr(1); 59 60 my @questions = $packet->question; 61 my $qname = $questions[0]->qname; 62 my $qtype = $questions[0]->qtype; 63 64 my $donotrespond = 0; 65 66 if ($qname eq "foo.info") { 67 $donotrespond = 1; 68 } elsif ($qname eq "cname1.example.com") { 69 # Data for the "cname + other data / 1" test 70 $packet->push("answer", new Net::DNS::RR("cname1.example.com 300 CNAME cname1.example.com")); 71 $packet->push("answer", new Net::DNS::RR("cname1.example.com 300 A 1.2.3.4")); 72 } elsif ($qname eq "cname2.example.com") { 73 # Data for the "cname + other data / 2" test: same RRs in opposite order 74 $packet->push("answer", new Net::DNS::RR("cname2.example.com 300 A 1.2.3.4")); 75 $packet->push("answer", new Net::DNS::RR("cname2.example.com 300 CNAME cname2.example.com")); 76 } elsif ($qname eq "www.example.org" || $qname eq "www.example.net" || 77 $qname eq "badcname.example.org" || 78 $qname eq "goodcname.example.org" || 79 $qname eq "foo.baddname.example.org" || 80 $qname eq "foo.gooddname.example.org") { 81 # Data for address/alias filtering. 82 $packet->header->aa(1); 83 if ($qtype eq "A") { 84 $packet->push("answer", 85 new Net::DNS::RR($qname . 86 " 300 A 192.0.2.1")); 87 } elsif ($qtype eq "AAAA") { 88 $packet->push("answer", 89 new Net::DNS::RR($qname . 90 " 300 AAAA 2001:db8:beef::1")); 91 } 92 } elsif ($qname eq "badcname.example.net" || 93 $qname eq "goodcname.example.net") { 94 # Data for CNAME/DNAME filtering. We need to make one-level 95 # delegation to avoid automatic acceptance for subdomain aliases 96 $packet->push("authority", new Net::DNS::RR("example.net 300 NS ns.example.net")); 97 $packet->push("additional", new Net::DNS::RR("ns.example.net 300 A 10.53.0.3")); 98 } elsif ($qname =~ /^nodata\.example\.net$/i) { 99 $packet->header->aa(1); 100 } elsif ($qname =~ /^nxdomain\.example\.net$/i) { 101 $packet->header->aa(1); 102 $packet->header->rcode(NXDOMAIN); 103 } elsif ($qname =~ /sub\.example\.org/) { 104 # Data for CNAME/DNAME filtering. The final answers are 105 # expected to be accepted regardless of the filter setting. 106 $packet->push("authority", new Net::DNS::RR("sub.example.org 300 NS ns.sub.example.org")); 107 $packet->push("additional", new Net::DNS::RR("ns.sub.example.org 300 A 10.53.0.3")); 108 } else { 109 # Data for the "bogus referrals" test 110 $packet->push("authority", new Net::DNS::RR("below.www.example.com 300 NS ns.below.www.example.com")); 111 $packet->push("additional", new Net::DNS::RR("ns.below.www.example.com 300 A 10.53.0.3")); 112 } 113 114 if ($donotrespond == 0) { 115 $sock->send($packet->data); 116 print "RESPONSE:\n"; 117 $packet->print; 118 print "\n"; 119 } 120} 121