Use isctest.asyncserver in the "zero" test

The original `ans.pl` server was based on a copy of the one in
`fetchlimit`, so there are some changes:

- The server now only responds with A replies (which is the only thing
  needed).
- The incrementing of the IP address goes beyond the least significant
  octet (so, after 192.0.2.255 it will yield 192.0.3.0).

diff --git a/bin/tests/system/zero/ans5/ans.pl b/bin/tests/system/zero/ans5/ans.pl
deleted file mode 100644 (file)
index 3ca1083..0000000
--- a/bin/tests/system/zero/ans5/ans.pl
+++ /dev/null
@@ -1,81 +0,0 @@
-#!/usr/bin/perl -w
-
-# 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.
-
-#
-# Don't respond if the "norespond" file exists; otherwise respond to
-# any A or AAAA query.
-#
-
-use IO::File;
-use IO::Socket;
-use Net::DNS;
-use Net::DNS::Packet;
-
-my $localport = int($ENV{'PORT'});
-if (!$localport) { $localport = 5300; }
-
-my $sock = IO::Socket::INET->new(LocalAddr => "10.53.0.5",
-   LocalPort => $localport, Proto => "udp") or die "$!";
-
-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 $octet = 0;
-
-for (;;) {
-       $sock->recv($buf, 512);
-
-       print "**** request from " , $sock->peerhost, " port ", $sock->peerport, "\n";
-
-       my $packet;
-
-       if ($Net::DNS::VERSION > 0.68) {
-               $packet = new Net::DNS::Packet(\$buf, 0);
-               $@ and die $@;
-       } else {
-               my $err;
-               ($packet, $err) = new Net::DNS::Packet(\$buf, 0);
-               $err and die $err;
-       }
-
-       print "REQUEST:\n";
-       $packet->print;
-
-       $packet->header->qr(1);
-
-       my @questions = $packet->question;
-       my $qname = $questions[0]->qname;
-       my $qtype = $questions[0]->qtype;
-
-       $packet->header->aa(1);
-       if ($qtype eq "A") {
-               $packet->push("answer",
-                             new Net::DNS::RR($qname .
-                                              " 0 A 192.0.2." . $octet));
-               $octet = $octet + 1;
-       } elsif ($qtype eq "AAAA") {
-               $packet->push("answer",
-                             new Net::DNS::RR($qname .
-                                               " 300 AAAA 2001:db8:beef::1"));
-       }
-
-       $sock->send($packet->data);
-       print "RESPONSE:\n";
-       $packet->print;
-       print "\n";
-}

diff --git a/bin/tests/system/zero/ans5/ans.py b/bin/tests/system/zero/ans5/ans.py
new file mode 100644 (file)
index 0000000..47b4da0
--- /dev/null
+++ b/bin/tests/system/zero/ans5/ans.py
@@ -0,0 +1,62 @@
+"""
+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.
+"""
+
+import ipaddress
+from typing import AsyncGenerator
+
+import dns.flags
+import dns.message
+import dns.rdata
+import dns.rdataclass
+import dns.rdatatype
+import dns.rrset
+
+from isctest.asyncserver import (
+    AsyncDnsServer,
+    DnsResponseSend,
+    QueryContext,
+    ResponseHandler,
+)
+
+
+class IncrementARecordHandler(ResponseHandler):
+    """
+    To test the TTL=0 behavior, increment the IPv4 address by one every
+    time we get queried.
+    """
+
+    def __init__(self):
+        self._ip_address = ipaddress.ip_address("192.0.2.0")
+
+    async def get_responses(
+        self, qctx: QueryContext
+    ) -> AsyncGenerator[DnsResponseSend, None]:
+        if qctx.qtype == dns.rdatatype.A:
+            rrset = dns.rrset.from_text(
+                qctx.qname, 0, qctx.qclass, dns.rdatatype.A, str(self._ip_address)
+            )
+            qctx.response.answer.append(rrset)
+            self._ip_address += 1
+
+        qctx.response.set_rcode(dns.rcode.NOERROR)
+        yield DnsResponseSend(qctx.response, authoritative=True)
+
+
+def main() -> None:
+    server = AsyncDnsServer()
+    server.install_response_handler(IncrementARecordHandler())
+    server.run()
+
+
+if __name__ == "__main__":
+    main()