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Easy Redis Java client and Real-Time Data Platform. Valkey compatible. Sync/Async/RxJava3/Reactive API. Client side caching. Over 50 Redis based Java objects and services: JCache API, Apache Tomcat, Hibernate, Spring, Set, Multimap, SortedSet, Map, List, Queue, Deque, Semaphore, Lock, AtomicLong, Map Reduce, Bloom filter, Scheduler, RPC
/*
* Copyright 2014 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:
*
* https://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.bootstrap.Bootstrap;
import io.netty.channel.AddressedEnvelope;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.ChannelPromise;
import io.netty.handler.codec.dns.AbstractDnsOptPseudoRrRecord;
import io.netty.handler.codec.dns.DnsQuery;
import io.netty.handler.codec.dns.DnsQuestion;
import io.netty.handler.codec.dns.DnsRecord;
import io.netty.handler.codec.dns.DnsRecordType;
import io.netty.handler.codec.dns.DnsResponse;
import io.netty.handler.codec.dns.DnsSection;
import io.netty.handler.codec.dns.TcpDnsQueryEncoder;
import io.netty.handler.codec.dns.TcpDnsResponseDecoder;
import io.netty.util.ReferenceCountUtil;
import io.netty.util.concurrent.Future;
import io.netty.util.concurrent.FutureListener;
import io.netty.util.concurrent.Promise;
import io.netty.util.internal.SystemPropertyUtil;
import io.netty.util.internal.ThrowableUtil;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.util.concurrent.CancellationException;
import java.util.concurrent.TimeUnit;
import static io.netty.util.internal.ObjectUtil.checkNotNull;
abstract class DnsQueryContext {
private static final InternalLogger logger = InternalLoggerFactory.getInstance(DnsQueryContext.class);
private static final long ID_REUSE_ON_TIMEOUT_DELAY_MILLIS;
static {
ID_REUSE_ON_TIMEOUT_DELAY_MILLIS =
SystemPropertyUtil.getLong("io.netty.resolver.dns.idReuseOnTimeoutDelayMillis", 10000);
logger.debug("-Dio.netty.resolver.dns.idReuseOnTimeoutDelayMillis: {}", ID_REUSE_ON_TIMEOUT_DELAY_MILLIS);
}
private static final TcpDnsQueryEncoder TCP_ENCODER = new TcpDnsQueryEncoder();
private final Channel channel;
private final InetSocketAddress nameServerAddr;
private final DnsQueryContextManager queryContextManager;
private final Promise> promise;
private final DnsQuestion question;
private final DnsRecord[] additionals;
private final DnsRecord optResource;
private final boolean recursionDesired;
private final Bootstrap socketBootstrap;
private final boolean retryWithTcpOnTimeout;
private final long queryTimeoutMillis;
private volatile Future timeoutFuture;
private int id = Integer.MIN_VALUE;
DnsQueryContext(Channel channel,
InetSocketAddress nameServerAddr,
DnsQueryContextManager queryContextManager,
int maxPayLoadSize,
boolean recursionDesired,
long queryTimeoutMillis,
DnsQuestion question,
DnsRecord[] additionals,
Promise> promise,
Bootstrap socketBootstrap,
boolean retryWithTcpOnTimeout) {
this.channel = checkNotNull(channel, "channel");
this.queryContextManager = checkNotNull(queryContextManager, "queryContextManager");
this.nameServerAddr = checkNotNull(nameServerAddr, "nameServerAddr");
this.question = checkNotNull(question, "question");
this.additionals = checkNotNull(additionals, "additionals");
this.promise = checkNotNull(promise, "promise");
this.recursionDesired = recursionDesired;
this.queryTimeoutMillis = queryTimeoutMillis;
this.socketBootstrap = socketBootstrap;
this.retryWithTcpOnTimeout = retryWithTcpOnTimeout;
if (maxPayLoadSize > 0 &&
// Only add the extra OPT record if there is not already one. This is required as only one is allowed
// as per RFC:
// - https://datatracker.ietf.org/doc/html/rfc6891#section-6.1.1
!hasOptRecord(additionals)) {
optResource = new AbstractDnsOptPseudoRrRecord(maxPayLoadSize, 0, 0) {
// We may want to remove this in the future and let the user just specify the opt record in the query.
};
} else {
optResource = null;
}
}
private static boolean hasOptRecord(DnsRecord[] additionals) {
if (additionals != null && additionals.length > 0) {
for (DnsRecord additional: additionals) {
if (additional.type() == DnsRecordType.OPT) {
return true;
}
}
}
return false;
}
/**
* Returns {@code true} if the query was completed already.
*
* @return {@code true} if done.
*/
final boolean isDone() {
return promise.isDone();
}
/**
* Returns the {@link DnsQuestion} that will be written as part of the {@link DnsQuery}.
*
* @return the question.
*/
final DnsQuestion question() {
return question;
}
/**
* Creates and returns a new {@link DnsQuery}.
*
* @param id the transaction id to use.
* @param nameServerAddr the nameserver to which the query will be send.
* @return the new query.
*/
protected abstract DnsQuery newQuery(int id, InetSocketAddress nameServerAddr);
/**
* Returns the protocol that is used for the query.
*
* @return the protocol.
*/
protected abstract String protocol();
/**
* Write the query and return the {@link ChannelFuture} that is completed once the write completes.
*
* @param flush {@code true} if {@link Channel#flush()} should be called as well.
* @return the {@link ChannelFuture} that is notified once once the write completes.
*/
final ChannelFuture writeQuery(boolean flush) {
assert id == Integer.MIN_VALUE : this.getClass().getSimpleName() +
".writeQuery(...) can only be executed once.";
if ((id = queryContextManager.add(nameServerAddr, this)) == -1) {
// We did exhaust the id space, fail the query
IllegalStateException e = new IllegalStateException("query ID space exhausted: " + question());
finishFailure("failed to send a query via " + protocol(), e, false);
return channel.newFailedFuture(e);
}
// Ensure we remove the id from the QueryContextManager once the query completes.
promise.addListener(new FutureListener>() {
@Override
public void operationComplete(Future> future) {
// Cancel the timeout task.
Future timeoutFuture = DnsQueryContext.this.timeoutFuture;
if (timeoutFuture != null) {
DnsQueryContext.this.timeoutFuture = null;
timeoutFuture.cancel(false);
}
Throwable cause = future.cause();
if (cause instanceof DnsNameResolverTimeoutException || cause instanceof CancellationException) {
// This query was failed due a timeout or cancellation. Let's delay the removal of the id to reduce
// the risk of reusing the same id again while the remote nameserver might send the response after
// the timeout.
channel.eventLoop().schedule(new Runnable() {
@Override
public void run() {
removeFromContextManager(nameServerAddr);
}
}, ID_REUSE_ON_TIMEOUT_DELAY_MILLIS, TimeUnit.MILLISECONDS);
} else {
// Remove the id from the manager as soon as the query completes. This may be because of success,
// failure or cancellation
removeFromContextManager(nameServerAddr);
}
}
});
final DnsQuestion question = question();
final DnsQuery query = newQuery(id, nameServerAddr);
query.setRecursionDesired(recursionDesired);
query.addRecord(DnsSection.QUESTION, question);
for (DnsRecord record: additionals) {
query.addRecord(DnsSection.ADDITIONAL, record);
}
if (optResource != null) {
query.addRecord(DnsSection.ADDITIONAL, optResource);
}
if (logger.isDebugEnabled()) {
logger.debug("{} WRITE: {}, [{}: {}], {}",
channel, protocol(), id, nameServerAddr, question);
}
return sendQuery(query, flush);
}
private void removeFromContextManager(InetSocketAddress nameServerAddr) {
DnsQueryContext self = queryContextManager.remove(nameServerAddr, id);
assert self == this : "Removed DnsQueryContext is not the correct instance";
}
private ChannelFuture sendQuery(final DnsQuery query, final boolean flush) {
final ChannelPromise writePromise = channel.newPromise();
writeQuery(query, flush, writePromise);
return writePromise;
}
private void writeQuery(final DnsQuery query,
final boolean flush, ChannelPromise promise) {
final ChannelFuture writeFuture = flush ? channel.writeAndFlush(query, promise) :
channel.write(query, promise);
if (writeFuture.isDone()) {
onQueryWriteCompletion(queryTimeoutMillis, writeFuture);
} else {
writeFuture.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) {
onQueryWriteCompletion(queryTimeoutMillis, writeFuture);
}
});
}
}
private void onQueryWriteCompletion(final long queryTimeoutMillis,
ChannelFuture writeFuture) {
if (!writeFuture.isSuccess()) {
finishFailure("failed to send a query '" + id + "' via " + protocol(), writeFuture.cause(), false);
return;
}
// Schedule a query timeout task if necessary.
if (queryTimeoutMillis > 0) {
timeoutFuture = channel.eventLoop().schedule(new Runnable() {
@Override
public void run() {
if (promise.isDone()) {
// Received a response before the query times out.
return;
}
finishFailure("query '" + id + "' via " + protocol() + " timed out after " +
queryTimeoutMillis + " milliseconds", null, true);
}
}, queryTimeoutMillis, TimeUnit.MILLISECONDS);
}
}
/**
* Notifies the original {@link Promise} that the response for the query was received.
* This method takes ownership of passed {@link AddressedEnvelope}.
*/
void finishSuccess(AddressedEnvelope envelope, boolean truncated) {
// Check if the response was not truncated or if a fallback to TCP is possible.
if (!truncated || !retryWithTcp(envelope)) {
final DnsResponse res = envelope.content();
if (res.count(DnsSection.QUESTION) != 1) {
logger.warn("{} Received a DNS response with invalid number of questions. Expected: 1, found: {}",
channel, envelope);
} else if (!question().equals(res.recordAt(DnsSection.QUESTION))) {
logger.warn("{} Received a mismatching DNS response. Expected: [{}], found: {}",
channel, question(), envelope);
} else if (trySuccess(envelope)) {
return; // Ownership transferred, don't release
}
envelope.release();
}
}
@SuppressWarnings("unchecked")
private boolean trySuccess(AddressedEnvelope envelope) {
return promise.trySuccess((AddressedEnvelope) envelope);
}
/**
* Notifies the original {@link Promise} that the query completes because of an failure.
*/
final boolean finishFailure(String message, Throwable cause, boolean timeout) {
if (promise.isDone()) {
return false;
}
final DnsQuestion question = question();
final StringBuilder buf = new StringBuilder(message.length() + 128);
buf.append('[')
.append(id)
.append(": ")
.append(nameServerAddr)
.append("] ")
.append(question)
.append(' ')
.append(message)
.append(" (no stack trace available)");
final DnsNameResolverException e;
if (timeout) {
// This was caused by a timeout so use DnsNameResolverTimeoutException to allow the user to
// handle it special (like retry the query).
e = new DnsNameResolverTimeoutException(nameServerAddr, question, buf.toString());
if (retryWithTcpOnTimeout && retryWithTcp(e)) {
// We did successfully retry with TCP.
return false;
}
} else {
e = new DnsNameResolverException(nameServerAddr, question, buf.toString(), cause);
}
return promise.tryFailure(e);
}
/**
* Retry the original query with TCP if possible.
*
* @param originalResult the result of the original {@link DnsQueryContext}.
* @return {@code true} if retry via TCP is supported and so the ownership of
* {@code originalResult} was transferred, {@code false} otherwise.
*/
private boolean retryWithTcp(final Object originalResult) {
if (socketBootstrap == null) {
return false;
}
socketBootstrap.connect(nameServerAddr).addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) {
if (!future.isSuccess()) {
logger.debug("{} Unable to fallback to TCP [{}: {}]",
future.channel(), id, nameServerAddr, future.cause());
// TCP fallback failed, just use the truncated response or error.
finishOriginal(originalResult, future);
return;
}
final Channel tcpCh = future.channel();
Promise> promise =
tcpCh.eventLoop().newPromise();
final TcpDnsQueryContext tcpCtx = new TcpDnsQueryContext(tcpCh,
(InetSocketAddress) tcpCh.remoteAddress(), queryContextManager, 0,
recursionDesired, queryTimeoutMillis, question(), additionals, promise);
tcpCh.pipeline().addLast(TCP_ENCODER);
tcpCh.pipeline().addLast(new TcpDnsResponseDecoder());
tcpCh.pipeline().addLast(new ChannelInboundHandlerAdapter() {
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) {
Channel tcpCh = ctx.channel();
DnsResponse response = (DnsResponse) msg;
int queryId = response.id();
if (logger.isDebugEnabled()) {
logger.debug("{} RECEIVED: TCP [{}: {}], {}", tcpCh, queryId,
tcpCh.remoteAddress(), response);
}
DnsQueryContext foundCtx = queryContextManager.get(nameServerAddr, queryId);
if (foundCtx != null && foundCtx.isDone()) {
logger.debug("{} Received a DNS response for a query that was timed out or cancelled " +
": TCP [{}: {}]", tcpCh, queryId, nameServerAddr);
response.release();
} else if (foundCtx == tcpCtx) {
tcpCtx.finishSuccess(new AddressedEnvelopeAdapter(
(InetSocketAddress) ctx.channel().remoteAddress(),
(InetSocketAddress) ctx.channel().localAddress(),
response), false);
} else {
response.release();
tcpCtx.finishFailure("Received TCP DNS response with unexpected ID", null, false);
if (logger.isDebugEnabled()) {
logger.debug("{} Received a DNS response with an unexpected ID: TCP [{}: {}]",
tcpCh, queryId, tcpCh.remoteAddress());
}
}
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
if (tcpCtx.finishFailure(
"TCP fallback error", cause, false) && logger.isDebugEnabled()) {
logger.debug("{} Error during processing response: TCP [{}: {}]",
ctx.channel(), id,
ctx.channel().remoteAddress(), cause);
}
}
});
promise.addListener(
new FutureListener>() {
@Override
public void operationComplete(
Future> future) {
if (future.isSuccess()) {
finishSuccess(future.getNow(), false);
// Release the original result.
ReferenceCountUtil.release(originalResult);
} else {
// TCP fallback failed, just use the truncated response or error.
finishOriginal(originalResult, future);
}
tcpCh.close();
}
});
tcpCtx.writeQuery(true);
}
});
return true;
}
@SuppressWarnings("unchecked")
private void finishOriginal(Object originalResult, Future future) {
if (originalResult instanceof Throwable) {
Throwable error = (Throwable) originalResult;
ThrowableUtil.addSuppressed(error, future.cause());
promise.tryFailure(error);
} else {
finishSuccess((AddressedEnvelope) originalResult, false);
}
}
private static final class AddressedEnvelopeAdapter implements AddressedEnvelope {
private final InetSocketAddress sender;
private final InetSocketAddress recipient;
private final DnsResponse response;
AddressedEnvelopeAdapter(InetSocketAddress sender, InetSocketAddress recipient, DnsResponse response) {
this.sender = sender;
this.recipient = recipient;
this.response = response;
}
@Override
public DnsResponse content() {
return response;
}
@Override
public InetSocketAddress sender() {
return sender;
}
@Override
public InetSocketAddress recipient() {
return recipient;
}
@Override
public AddressedEnvelope retain() {
response.retain();
return this;
}
@Override
public AddressedEnvelope retain(int increment) {
response.retain(increment);
return this;
}
@Override
public AddressedEnvelope touch() {
response.touch();
return this;
}
@Override
public AddressedEnvelope touch(Object hint) {
response.touch(hint);
return this;
}
@Override
public int refCnt() {
return response.refCnt();
}
@Override
public boolean release() {
return response.release();
}
@Override
public boolean release(int decrement) {
return response.release(decrement);
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (!(obj instanceof AddressedEnvelope)) {
return false;
}
@SuppressWarnings("unchecked")
final AddressedEnvelope that = (AddressedEnvelope) obj;
if (sender() == null) {
if (that.sender() != null) {
return false;
}
} else if (!sender().equals(that.sender())) {
return false;
}
if (recipient() == null) {
if (that.recipient() != null) {
return false;
}
} else if (!recipient().equals(that.recipient())) {
return false;
}
return response.equals(obj);
}
@Override
public int hashCode() {
int hashCode = response.hashCode();
if (sender() != null) {
hashCode = hashCode * 31 + sender().hashCode();
}
if (recipient() != null) {
hashCode = hashCode * 31 + recipient().hashCode();
}
return hashCode;
}
}
}
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