1#!/usr/bin/perl 2# 3# Copyright (C) 2004, 2007, 2009, 2010 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 1.15 2010/05/19 09:33:50 tbox 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 $sock = IO::Socket::INET->new(LocalAddr => "10.53.0.2", 30 LocalPort => 5300, Proto => "udp") or die "$!"; 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, $err) = new Net::DNS::Packet(\$buf, 0); 46 $err and die $err; 47 48 print "REQUEST:\n"; 49 $packet->print; 50 51 $packet->header->qr(1); 52 53 my @questions = $packet->question; 54 my $qname = $questions[0]->qname; 55 my $qtype = $questions[0]->qtype; 56 57 if ($qname eq "cname1.example.com") { 58 # Data for the "cname + other data / 1" test 59 $packet->push("answer", new Net::DNS::RR("cname1.example.com 300 CNAME cname1.example.com")); 60 $packet->push("answer", new Net::DNS::RR("cname1.example.com 300 A 1.2.3.4")); 61 } elsif ($qname eq "cname2.example.com") { 62 # Data for the "cname + other data / 2" test: same RRs in opposite order 63 $packet->push("answer", new Net::DNS::RR("cname2.example.com 300 A 1.2.3.4")); 64 $packet->push("answer", new Net::DNS::RR("cname2.example.com 300 CNAME cname2.example.com")); 65 } elsif ($qname eq "www.example.org" || $qname eq "www.example.net" || 66 $qname eq "badcname.example.org" || 67 $qname eq "goodcname.example.org" || 68 $qname eq "foo.baddname.example.org" || 69 $qname eq "foo.gooddname.example.org") { 70 # Data for address/alias filtering. 71 $packet->header->aa(1); 72 if ($qtype eq "A") { 73 $packet->push("answer", 74 new Net::DNS::RR($qname . 75 " 300 A 192.0.2.1")); 76 } elsif ($qtype eq "AAAA") { 77 $packet->push("answer", 78 new Net::DNS::RR($qname . 79 " 300 AAAA 2001:db8:beef::1")); 80 } 81 } elsif ($qname eq "badcname.example.net" || 82 $qname eq "goodcname.example.net") { 83 # Data for CNAME/DNAME filtering. We need to make one-level 84 # delegation to avoid automatic acceptance for subdomain aliases 85 $packet->push("authority", new Net::DNS::RR("example.net 300 NS ns.example.net")); 86 $packet->push("additional", new Net::DNS::RR("ns.example.net 300 A 10.53.0.3")); 87 } elsif ($qname =~ /^nodata\.example\.net$/i) { 88 $packet->header->aa(1); 89 } elsif ($qname =~ /^nxdomain\.example\.net$/i) { 90 $packet->header->aa(1); 91 $packet->header->rcode(NXDOMAIN); 92 } elsif ($qname =~ /sub\.example\.org/) { 93 # Data for CNAME/DNAME filtering. The final answers are 94 # expected to be accepted regardless of the filter setting. 95 $packet->push("authority", new Net::DNS::RR("sub.example.org 300 NS ns.sub.example.org")); 96 $packet->push("additional", new Net::DNS::RR("ns.sub.example.org 300 A 10.53.0.3")); 97 } else { 98 # Data for the "bogus referrals" test 99 $packet->push("authority", new Net::DNS::RR("below.www.example.com 300 NS ns.below.www.example.com")); 100 $packet->push("additional", new Net::DNS::RR("ns.below.www.example.com 300 A 10.53.0.3")); 101 } 102 103 $sock->send($packet->data); 104 105 print "RESPONSE:\n"; 106 $packet->print; 107 print "\n"; 108} 109