netty5/resolver-dns/src/test/java/io/netty/resolver/dns/TestDnsServer.java
Norman Maurer bbb6e126b1
Correctly handle DNS redirects for NS servers that have no ADDITIONAL record (#8177)
Motiviation:

We incorrectly did ignore NS servers during redirect which had no ADDITIONAL record. This could at worse have the affect that we failed the query completely as none of the NS servers had a ADDITIONAL record. Beside this using a DnsCache to cache authoritative nameservers does not work in practise as we we need different features and semantics when cache these servers (for example we also want to cache unresolved nameservers and resolve these on the fly when needed).

Modifications:

- Correctly take NS records into account that have no matching ADDITIONAL record
- Correctly handle multiple ADDITIONAL records for the same NS record
- Introduce AuthoritativeDnsServerCache as a replacement of the DnsCache when caching authoritative nameservers + adding default implementation
- Add an adapter layer to reduce API breakage as much as possible
- Replace DnsNameResolver.uncachedRedirectDnsServerStream(...) with newRedirectDnsServerStream(...)
- Add unit tests

Result:

Our DnsResolver now correctly handle redirects in all cases.
2018-08-22 17:49:22 +02:00

329 lines
13 KiB
Java

/*
* Copyright 2016 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.resolver.dns;
import io.netty.util.NetUtil;
import io.netty.util.internal.PlatformDependent;
import org.apache.directory.server.dns.DnsServer;
import org.apache.directory.server.dns.io.encoder.DnsMessageEncoder;
import org.apache.directory.server.dns.io.encoder.ResourceRecordEncoder;
import org.apache.directory.server.dns.messages.DnsMessage;
import org.apache.directory.server.dns.messages.QuestionRecord;
import org.apache.directory.server.dns.messages.RecordClass;
import org.apache.directory.server.dns.messages.RecordType;
import org.apache.directory.server.dns.messages.ResourceRecord;
import org.apache.directory.server.dns.messages.ResourceRecordImpl;
import org.apache.directory.server.dns.messages.ResourceRecordModifier;
import org.apache.directory.server.dns.protocol.DnsProtocolHandler;
import org.apache.directory.server.dns.protocol.DnsUdpDecoder;
import org.apache.directory.server.dns.protocol.DnsUdpEncoder;
import org.apache.directory.server.dns.store.DnsAttribute;
import org.apache.directory.server.dns.store.RecordStore;
import org.apache.directory.server.protocol.shared.transport.UdpTransport;
import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.filter.codec.ProtocolCodecFactory;
import org.apache.mina.filter.codec.ProtocolCodecFilter;
import org.apache.mina.filter.codec.ProtocolDecoder;
import org.apache.mina.filter.codec.ProtocolEncoder;
import org.apache.mina.filter.codec.ProtocolEncoderOutput;
import org.apache.mina.transport.socket.DatagramAcceptor;
import org.apache.mina.transport.socket.DatagramSessionConfig;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
class TestDnsServer extends DnsServer {
private static final Map<String, byte[]> BYTES = new HashMap<String, byte[]>();
private static final String[] IPV6_ADDRESSES;
static {
BYTES.put("::1", new byte[]{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1});
BYTES.put("0:0:0:0:0:0:1:1", new byte[]{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1});
BYTES.put("0:0:0:0:0:1:1:1", new byte[]{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1});
BYTES.put("0:0:0:0:1:1:1:1", new byte[]{0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1});
BYTES.put("0:0:0:1:1:1:1:1", new byte[]{0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1});
BYTES.put("0:0:1:1:1:1:1:1", new byte[]{0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1});
BYTES.put("0:1:1:1:1:1:1:1", new byte[]{0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1});
BYTES.put("1:1:1:1:1:1:1:1", new byte[]{0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1});
IPV6_ADDRESSES = BYTES.keySet().toArray(new String[0]);
}
private final RecordStore store;
TestDnsServer(Set<String> domains) {
this(new TestRecordStore(domains));
}
TestDnsServer(RecordStore store) {
this.store = store;
}
@Override
public void start() throws IOException {
InetSocketAddress address = new InetSocketAddress(NetUtil.LOCALHOST4, 0);
UdpTransport transport = new UdpTransport(address.getHostName(), address.getPort());
setTransports(transport);
DatagramAcceptor acceptor = transport.getAcceptor();
acceptor.setHandler(new DnsProtocolHandler(this, store) {
@Override
public void sessionCreated(IoSession session) {
// USe our own codec to support AAAA testing
session.getFilterChain()
.addFirst("codec", new ProtocolCodecFilter(new TestDnsProtocolUdpCodecFactory()));
}
});
((DatagramSessionConfig) acceptor.getSessionConfig()).setReuseAddress(true);
// Start the listener
acceptor.bind();
}
public InetSocketAddress localAddress() {
return (InetSocketAddress) getTransports()[0].getAcceptor().getLocalAddress();
}
protected DnsMessage filterMessage(DnsMessage message) {
return message;
}
protected static ResourceRecord newARecord(String name, String ipAddress) {
return newAddressRecord(name, RecordType.A, ipAddress);
}
protected static ResourceRecord newNsRecord(String dnsname, String domainName) {
ResourceRecordModifier rm = new ResourceRecordModifier();
rm.setDnsClass(RecordClass.IN);
rm.setDnsName(dnsname);
rm.setDnsTtl(100);
rm.setDnsType(RecordType.NS);
rm.put(DnsAttribute.DOMAIN_NAME, domainName);
return rm.getEntry();
}
protected static ResourceRecord newAddressRecord(String name, RecordType type, String address) {
ResourceRecordModifier rm = new ResourceRecordModifier();
rm.setDnsClass(RecordClass.IN);
rm.setDnsName(name);
rm.setDnsTtl(100);
rm.setDnsType(type);
rm.put(DnsAttribute.IP_ADDRESS, address);
return rm.getEntry();
}
/**
* {@link ProtocolCodecFactory} which allows to test AAAA resolution.
*/
private final class TestDnsProtocolUdpCodecFactory implements ProtocolCodecFactory {
private final DnsMessageEncoder encoder = new DnsMessageEncoder();
private final TestAAAARecordEncoder recordEncoder = new TestAAAARecordEncoder();
@Override
public ProtocolEncoder getEncoder(IoSession session) {
return new DnsUdpEncoder() {
@Override
public void encode(IoSession session, Object message, ProtocolEncoderOutput out) {
IoBuffer buf = IoBuffer.allocate(1024);
DnsMessage dnsMessage = filterMessage((DnsMessage) message);
encoder.encode(buf, dnsMessage);
for (ResourceRecord record : dnsMessage.getAnswerRecords()) {
// This is a hack to allow to also test for AAAA resolution as DnsMessageEncoder
// does not support it and it is hard to extend, because the interesting methods
// are private...
// In case of RecordType.AAAA we need to encode the RecordType by ourselves.
if (record.getRecordType() == RecordType.AAAA) {
try {
recordEncoder.put(buf, record);
} catch (IOException e) {
// Should never happen
throw new IllegalStateException(e);
}
}
}
buf.flip();
out.write(buf);
}
};
}
@Override
public ProtocolDecoder getDecoder(IoSession session) {
return new DnsUdpDecoder();
}
private final class TestAAAARecordEncoder extends ResourceRecordEncoder {
@Override
protected void putResourceRecordData(IoBuffer ioBuffer, ResourceRecord resourceRecord) {
byte[] bytes = BYTES.get(resourceRecord.get(DnsAttribute.IP_ADDRESS));
if (bytes == null) {
throw new IllegalStateException(resourceRecord.get(DnsAttribute.IP_ADDRESS));
}
// encode the ::1
ioBuffer.put(bytes);
}
}
}
static final class MapRecordStoreA implements RecordStore {
private final Map<String, List<String>> domainMap;
MapRecordStoreA(Set<String> domains, int length) {
domainMap = new HashMap<String, List<String>>(domains.size());
for (String domain : domains) {
List<String> addresses = new ArrayList<String>(length);
for (int i = 0; i < length; i++) {
addresses.add(TestRecordStore.nextIp());
}
domainMap.put(domain, addresses);
}
}
MapRecordStoreA(Set<String> domains) {
this(domains, 1);
}
public String getAddress(String domain) {
return domainMap.get(domain).get(0);
}
public List<String> getAddresses(String domain) {
return domainMap.get(domain);
}
@Override
public Set<ResourceRecord> getRecords(QuestionRecord questionRecord) {
String name = questionRecord.getDomainName();
List<String> addresses = domainMap.get(name);
if (addresses != null && questionRecord.getRecordType() == RecordType.A) {
Set<ResourceRecord> records = new LinkedHashSet<ResourceRecord>();
for (String address : addresses) {
Map<String, Object> attributes = new HashMap<String, Object>();
attributes.put(DnsAttribute.IP_ADDRESS.toLowerCase(), address);
records.add(new TestResourceRecord(name, questionRecord.getRecordType(), attributes));
}
return records;
}
return null;
}
}
private static final class TestRecordStore implements RecordStore {
private static final int[] NUMBERS = new int[254];
private static final char[] CHARS = new char[26];
static {
for (int i = 0; i < NUMBERS.length; i++) {
NUMBERS[i] = i + 1;
}
for (int i = 0; i < CHARS.length; i++) {
CHARS[i] = (char) ('a' + i);
}
}
private static int index(int arrayLength) {
return Math.abs(PlatformDependent.threadLocalRandom().nextInt()) % arrayLength;
}
private static String nextDomain() {
return CHARS[index(CHARS.length)] + ".netty.io";
}
private static String nextIp() {
return ipPart() + "." + ipPart() + '.' + ipPart() + '.' + ipPart();
}
private static int ipPart() {
return NUMBERS[index(NUMBERS.length)];
}
private static String nextIp6() {
return IPV6_ADDRESSES[index(IPV6_ADDRESSES.length)];
}
private final Set<String> domains;
private TestRecordStore(Set<String> domains) {
this.domains = domains;
}
@Override
public Set<ResourceRecord> getRecords(QuestionRecord questionRecord) {
String name = questionRecord.getDomainName();
if (domains.contains(name)) {
Map<String, Object> attr = new HashMap<String, Object>();
switch (questionRecord.getRecordType()) {
case A:
do {
attr.put(DnsAttribute.IP_ADDRESS.toLowerCase(Locale.US), nextIp());
} while (PlatformDependent.threadLocalRandom().nextBoolean());
break;
case AAAA:
do {
attr.put(DnsAttribute.IP_ADDRESS.toLowerCase(Locale.US), nextIp6());
} while (PlatformDependent.threadLocalRandom().nextBoolean());
break;
case MX:
int priority = 0;
do {
attr.put(DnsAttribute.DOMAIN_NAME.toLowerCase(Locale.US), nextDomain());
attr.put(DnsAttribute.MX_PREFERENCE.toLowerCase(Locale.US), String.valueOf(++priority));
} while (PlatformDependent.threadLocalRandom().nextBoolean());
break;
default:
return null;
}
return Collections.<ResourceRecord>singleton(
new TestResourceRecord(name, questionRecord.getRecordType(), attr));
}
return null;
}
}
static final class TestResourceRecord extends ResourceRecordImpl {
TestResourceRecord(String domainName, RecordType recordType, Map<String, Object> attributes) {
super(domainName, recordType, RecordClass.IN, 100, attributes);
}
@Override
public int hashCode() {
return System.identityHashCode(this);
}
@Override
public boolean equals(Object o) {
return o == this;
}
}
}