234 lines
8.1 KiB
Perl
234 lines
8.1 KiB
Perl
#!/usr/bin/perl
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# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
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#
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# SPDX-License-Identifier: MPL-2.0
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#
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# This Source Code Form is subject to the terms of the Mozilla Public
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# License, v. 2.0. If a copy of the MPL was not distributed with this
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# file, you can obtain one at https://mozilla.org/MPL/2.0/.
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#
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# See the COPYRIGHT file distributed with this work for additional
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# information regarding copyright ownership.
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#
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# Ad hoc name server
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#
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use IO::File;
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use IO::Socket;
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use Net::DNS;
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use Net::DNS::Packet;
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# Ignore SIGPIPE so we won't fail if peer closes a TCP socket early
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local $SIG{PIPE} = 'IGNORE';
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# Flush logged output after every line
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local $| = 1;
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my $localport = int($ENV{'PORT'});
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if (!$localport) { $localport = 5300; }
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my $server_addr = "10.53.0.3";
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my $udpsock = IO::Socket::INET->new(LocalAddr => "$server_addr",
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LocalPort => $localport, Proto => "udp", Reuse => 1) or die "$!";
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my $tcpsock = IO::Socket::INET->new(LocalAddr => "$server_addr",
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LocalPort => $localport, Proto => "tcp", Listen => 5, Reuse => 1) or die "$!";
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my $pidf = new IO::File "ans.pid", "w" or die "cannot open pid file: $!";
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print $pidf "$$\n" or die "cannot write pid file: $!";
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$pidf->close or die "cannot close pid file: $!";
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sub rmpid { unlink "ans.pid"; exit 1; };
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$SIG{INT} = \&rmpid;
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$SIG{TERM} = \&rmpid;
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sub handleQuery {
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my $buf = shift;
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my $packet;
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if ($Net::DNS::VERSION > 0.68) {
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$packet = new Net::DNS::Packet(\$buf, 0);
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$@ and die $@;
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} else {
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my $err;
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($packet, $err) = new Net::DNS::Packet(\$buf, 0);
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$err and die $err;
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}
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print "REQUEST:\n";
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$packet->print;
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$packet->header->qr(1);
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$packet->header->aa(1);
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my @questions = $packet->question;
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my $qname = $questions[0]->qname;
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my $qtype = $questions[0]->qtype;
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if ($qname eq "example.net" && $qtype eq "NS") {
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$packet->push("answer", new Net::DNS::RR($qname . " 300 NS ns.example.net"));
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$packet->push("additional", new Net::DNS::RR("ns.example.net 300 A 10.53.0.3"));
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} elsif ($qname eq "ns.example.net") {
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$packet->push("answer", new Net::DNS::RR($qname . " 300 A 10.53.0.3"));
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} elsif ($qname eq "nodata.example.net") {
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# Do not add a SOA RRset.
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} elsif ($qname eq "noresponse.example.net") {
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# Do not response.
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print "RESPONSE:\n";
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return "";
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} elsif ($qname eq "nxdomain.example.net") {
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# Do not add a SOA RRset.
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$packet->header->rcode(NXDOMAIN);
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} elsif ($qname eq "www.example.net") {
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# Data for address/alias filtering.
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if ($qtype eq "A") {
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$packet->push("answer", new Net::DNS::RR($qname . " 300 A 192.0.2.1"));
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} elsif ($qtype eq "AAAA") {
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$packet->push("answer", new Net::DNS::RR($qname . " 300 AAAA 2001:db8:beef::1"));
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}
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} elsif ($qname eq "badcname.example.net") {
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$packet->push("answer",
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new Net::DNS::RR($qname .
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" 300 CNAME badcname.example.org"));
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} elsif (($qname eq "baddname.example.net" || $qname eq "gooddname.example.net") && $qtype eq "NS") {
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$packet->push("authority", new Net::DNS::RR("example.net IN SOA (1 2 3 4 5)"))
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} elsif ($qname eq "foo.baddname.example.net") {
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$packet->push("answer",
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new Net::DNS::RR("baddname.example.net" .
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" 300 DNAME baddname.example.org"));
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} elsif ($qname eq "foo.gooddname.example.net") {
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$packet->push("answer",
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new Net::DNS::RR("gooddname.example.net" .
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" 300 DNAME gooddname.example.org"));
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} elsif ($qname eq "goodcname.example.net") {
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$packet->push("answer",
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new Net::DNS::RR($qname .
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" 300 CNAME goodcname.example.org"));
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} elsif ($qname =~ /^longcname/) {
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$cname = $qname =~ s/longcname/longcnamex/r;
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$packet->push("answer", new Net::DNS::RR($qname . " 300 CNAME " . $cname));
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} elsif ($qname =~ /^nodata\.example\.net$/i) {
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$packet->header->aa(1);
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} elsif ($qname =~ /^nxdomain\.example\.net$/i) {
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$packet->header->aa(1);
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$packet->header->rcode(NXDOMAIN);
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} elsif ($qname =~ /lame\.example\.org/) {
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$packet->header->ad(0);
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$packet->header->aa(0);
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$packet->push("authority", new Net::DNS::RR("lame.example.org 300 NS ns.lame.example.org"));
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$packet->push("additional", new Net::DNS::RR("ns.lame.example.org 300 A 10.53.0.3"));
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} elsif ($qname eq "large-referral.example.net") {
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for (my $i = 1; $i < 1000; $i++) {
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$packet->push("authority", new Net::DNS::RR("large-referral.example.net 300 NS ns" . $i . ".fake.redirect.com"));
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}
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# No glue records
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} elsif ($qname eq "foo.bar.sub.tld1") {
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$packet->push("answer", new Net::DNS::RR("$qname 300 TXT baz"));
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} elsif ($qname eq "cname.sub.example.org") {
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$packet->push("answer",
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new Net::DNS::RR($qname .
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" 300 CNAME ok.sub.example.org"));
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} elsif ($qname eq "ok.sub.example.org") {
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$packet->push("answer",
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new Net::DNS::RR($qname . " 300 A 192.0.2.1"));
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} elsif ($qname eq "www.dname.sub.example.org") {
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$packet->push("answer",
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new Net::DNS::RR("dname.sub.example.org" .
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" 300 DNAME ok.sub.example.org"));
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} elsif ($qname eq "www.ok.sub.example.org") {
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$packet->push("answer",
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new Net::DNS::RR($qname . " 300 A 192.0.2.1"));
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} elsif ($qname eq "foo.glue-in-answer.example.org") {
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$packet->push("answer", new Net::DNS::RR($qname . " 300 A 192.0.2.1"));
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} elsif ($qname eq "ns.example.net") {
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$packet->push("answer",
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new Net::DNS::RR($qname .
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" 300 A 10.53.0.3"));
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} elsif ($qname =~ /\.partial-formerr/) {
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$packet->push("answer",
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new Net::DNS::RR($qname . " 1 A 10.53.0.3"));
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} elsif ($qname eq "gl6412") {
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if ($qtype eq "SOA") {
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$packet->push("answer",
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new Net::DNS::RR($qname . " 300 SOA . . 0 0 0 0 0"));
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} elsif ($qtype eq "NS") {
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$packet->push("answer",
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new Net::DNS::RR($qname . " 300 NS ns2" . $qname));
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$packet->push("answer",
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new Net::DNS::RR($qname . " 300 NS ns3" . $qname));
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} else {
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$packet->push("authority",
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new Net::DNS::RR($qname . " 300 SOA . . 0 0 0 0 0"));
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}
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} elsif ($qname eq "a.gl6412" || $qname eq "a.a.gl6412") {
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$packet->push("authority",
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new Net::DNS::RR($qname . " 300 SOA . . 0 0 0 0 0"));
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} elsif ($qname eq "ns2.gl6412") {
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if ($qtype eq "A") {
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$packet->push("answer",
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new Net::DNS::RR($qname . " 300 A 10.53.0.2"));
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} else {
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$packet->push("authority",
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new Net::DNS::RR($qname . " 300 SOA . . 0 0 0 0 0"));
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}
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} elsif ($qname eq "ns3.gl6412") {
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if ($qtype eq "A") {
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$packet->push("answer",
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new Net::DNS::RR($qname . " 300 A 10.53.0.3"));
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} else {
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$packet->push("authority",
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new Net::DNS::RR($qname . " 300 SOA . . 0 0 0 0 0"));
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}
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} else {
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$packet->push("answer", new Net::DNS::RR("www.example.com 300 A 1.2.3.4"));
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}
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print "RESPONSE:\n";
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$packet->print;
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return $packet->data;
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}
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# Main
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my $rin;
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my $rout;
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for (;;) {
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$rin = '';
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vec($rin, fileno($tcpsock), 1) = 1;
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vec($rin, fileno($udpsock), 1) = 1;
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select($rout = $rin, undef, undef, undef);
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if (vec($rout, fileno($udpsock), 1)) {
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printf "UDP request\n";
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my $buf;
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$udpsock->recv($buf, 512);
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my $result = handleQuery($buf);
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my $num_chars = $udpsock->send($result);
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print " Sent $num_chars bytes via UDP\n";
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} elsif (vec($rout, fileno($tcpsock), 1)) {
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my $conn = $tcpsock->accept;
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my $buf;
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for (;;) {
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my $lenbuf;
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my $n = $conn->sysread($lenbuf, 2);
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last unless $n == 2;
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my $len = unpack("n", $lenbuf);
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$n = $conn->sysread($buf, $len);
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last unless $n == $len;
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print "TCP request\n";
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my $result = handleQuery($buf);
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$len = length($result);
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if ($len != 0) {
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$conn->syswrite(pack("n", $len), 2);
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$n = $conn->syswrite($result, $len);
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} else {
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$n = 0;
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}
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print " Sent: $n chars via TCP\n";
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}
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$conn->close;
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}
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}
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