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1 files changed, 235 insertions, 0 deletions
diff --git a/bin/tests/system/reclimit/ans2/ans.pl b/bin/tests/system/reclimit/ans2/ans.pl
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+++ b/bin/tests/system/reclimit/ans2/ans.pl
@@ -0,0 +1,235 @@
+#!/usr/bin/env perl
+
+# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+#
+# SPDX-License-Identifier: MPL-2.0
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, you can obtain one at https://mozilla.org/MPL/2.0/.
+#
+# See the COPYRIGHT file distributed with this work for additional
+# information regarding copyright ownership.
+
+use strict;
+use warnings;
+
+use IO::File;
+use IO::Socket;
+use Net::DNS;
+
+my $localaddr = "10.53.0.2";
+my $limit = getlimit();
+my $no_more_waiting = 0;
+my @delayed_response;
+my $timeout;
+
+my $localport = int($ENV{'PORT'});
+if (!$localport) { $localport = 5300; }
+
+my $udpsock = IO::Socket::INET->new(LocalAddr => "$localaddr",
+ LocalPort => $localport, Proto => "udp", Reuse => 1) or die "$!";
+
+my $pidf = new IO::File "ans.pid", "w" or die "cannot open pid file: $!";
+print $pidf "$$\n" or die "cannot write pid file: $!";
+$pidf->close or die "cannot close pid file: $!";
+sub rmpid { unlink "ans.pid"; exit 1; };
+
+$SIG{INT} = \&rmpid;
+$SIG{TERM} = \&rmpid;
+
+my $count = 0;
+my $send_response = 0;
+
+sub getlimit {
+ if ( -e "ans.limit") {
+ open(FH, "<", "ans.limit");
+ my $line = <FH>;
+ chomp $line;
+ close FH;
+ if ($line =~ /^\d+$/) {
+ return $line;
+ }
+ }
+
+ return 0;
+}
+
+# If $wait == 0 is returned, returned reply will be sent immediately.
+# If $wait == 1 is returned, sending the returned reply might be delayed; see
+# comments inside handle_UDP() for details.
+sub reply_handler {
+ my ($qname, $qclass, $qtype) = @_;
+ my ($rcode, @ans, @auth, @add, $wait);
+
+ print ("request: $qname/$qtype\n");
+ STDOUT->flush();
+
+ $wait = 0;
+ $count += 1;
+
+ if ($qname eq "count" ) {
+ if ($qtype eq "TXT") {
+ my ($ttl, $rdata) = (0, "$count");
+ my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
+ push @ans, $rr;
+ print ("\tcount: $count\n");
+ }
+ $rcode = "NOERROR";
+ } elsif ($qname eq "reset" ) {
+ $count = 0;
+ $send_response = 0;
+ $limit = getlimit();
+ $rcode = "NOERROR";
+ print ("\tlimit: $limit\n");
+ } elsif ($qname eq "direct.example.org" ) {
+ if ($qtype eq "A") {
+ my ($ttl, $rdata) = (3600, $localaddr);
+ my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
+ push @ans, $rr;
+ }
+ $rcode = "NOERROR";
+ } elsif ($qname eq "indirect1.example.org" ||
+ $qname eq "indirect2.example.org" ||
+ $qname eq "indirect3.example.org" ||
+ $qname eq "indirect4.example.org" ||
+ $qname eq "indirect5.example.org" ||
+ $qname eq "indirect6.example.org" ||
+ $qname eq "indirect7.example.org" ||
+ $qname eq "indirect8.example.org") {
+ if (! $send_response) {
+ my $rr = new Net::DNS::RR("$qname 86400 $qclass NS ns1.1.example.org");
+ push @auth, $rr;
+ } elsif ($qtype eq "A") {
+ my ($ttl, $rdata) = (3600, $localaddr);
+ my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
+ push @ans, $rr;
+ }
+ $rcode = "NOERROR";
+ } elsif ($qname =~ /^ns1\.(\d+)\.example\.org$/) {
+ my $next = $1 + 1;
+ $wait = 1;
+ if ($limit == 0 || (! $send_response && $next <= $limit)) {
+ my $rr = new Net::DNS::RR("$1.example.org 86400 $qclass NS ns1.$next.example.org");
+ push @auth, $rr;
+ } else {
+ $send_response = 1;
+ if ($qtype eq "A") {
+ my ($ttl, $rdata) = (3600, "10.53.0.4");
+ my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
+ print("\tresponse: $qname $ttl $qclass $qtype $rdata\n");
+ push @ans, $rr;
+ }
+ }
+ $rcode = "NOERROR";
+ } elsif ($qname eq "direct.example.net" ) {
+ if ($qtype eq "A") {
+ my ($ttl, $rdata) = (3600, $localaddr);
+ my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
+ push @ans, $rr;
+ }
+ $rcode = "NOERROR";
+ } elsif( $qname =~ /^ns1\.(\d+)\.example\.net$/ ) {
+ my $next = ($1 + 1) * 16;
+ for (my $i = 1; $i < 16; $i++) {
+ my $s = $next + $i;
+ my $rr = new Net::DNS::RR("$1.example.net 86400 $qclass NS ns1.$s.example.net");
+ push @auth, $rr;
+ $rr = new Net::DNS::RR("ns1.$s.example.net 86400 $qclass A 10.53.0.7");
+ push @add, $rr;
+ }
+ $rcode = "NOERROR";
+ } else {
+ $rcode = "NXDOMAIN";
+ }
+
+ return ($rcode, \@ans, \@auth, \@add, $wait);
+}
+
+sub handleUDP {
+ my ($buf, $peer) = @_;
+ my ($request, $rcode, $ans, $auth, $add, $wait);
+
+ $request = new Net::DNS::Packet(\$buf, 0);
+ $@ and die $@;
+
+ my ($question) = $request->question;
+ my $qname = $question->qname;
+ my $qclass = $question->qclass;
+ my $qtype = $question->qtype;
+
+ ($rcode, $ans, $auth, $add, $wait) = reply_handler($qname, $qclass, $qtype);
+
+ my $reply = $request->reply();
+
+ $reply->header->rcode($rcode);
+ $reply->header->aa(@$ans ? 1 : 0);
+ $reply->header->id($request->header->id);
+ $reply->{answer} = $ans if $ans;
+ $reply->{authority} = $auth if $auth;
+ $reply->{additional} = $add if $add;
+
+ if ($wait) {
+ # reply_handler() asked us to delay sending this reply until
+ # another reply with $wait == 1 is generated or a timeout
+ # occurs.
+ if (@delayed_response) {
+ # A delayed reply is already queued, so we can now send
+ # both the delayed reply and the current reply.
+ send_delayed_response();
+ return $reply;
+ } elsif ($no_more_waiting) {
+ # It was determined before that there is no point in
+ # waiting for "accompanying" queries. Thus, send the
+ # current reply immediately.
+ return $reply;
+ } else {
+ # No delayed reply is queued and the client is expected
+ # to send an "accompanying" query shortly. Do not send
+ # the current reply right now, just save it for later
+ # and wait for an "accompanying" query to be received.
+ @delayed_response = ($reply, $peer);
+ $timeout = 0.5;
+ return;
+ }
+ } else {
+ # Send reply immediately.
+ return $reply;
+ }
+}
+
+sub send_delayed_response {
+ my ($reply, $peer) = @delayed_response;
+ # Truncation to 512 bytes is required for triggering "NS explosion" on
+ # builds without IPv6 support
+ $udpsock->send($reply->data(512), 0, $peer);
+ undef @delayed_response;
+ undef $timeout;
+}
+
+# Main
+my $rin;
+my $rout;
+for (;;) {
+ $rin = '';
+ vec($rin, fileno($udpsock), 1) = 1;
+
+ select($rout = $rin, undef, undef, $timeout);
+
+ if (vec($rout, fileno($udpsock), 1)) {
+ my ($buf, $peer, $reply);
+ $udpsock->recv($buf, 512);
+ $peer = $udpsock->peername();
+ $reply = handleUDP($buf, $peer);
+ # Truncation to 512 bytes is required for triggering "NS
+ # explosion" on builds without IPv6 support
+ $udpsock->send($reply->data(512), 0, $peer) if $reply;
+ } else {
+ # An "accompanying" query was expected to come in, but did not.
+ # Assume the client never sends "accompanying" queries to
+ # prevent pointlessly waiting for them ever again.
+ $no_more_waiting = 1;
+ # Send the delayed reply to the query which caused us to wait.
+ send_delayed_response();
+ }
+}
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