a214f2eb96
Motivation: We did not handle the case when the query was cancelled which could lead to an exhausted id space. Beside this we did not not cancel the timeout on failed promises. Modifications: - Do the removal of the id from the manager in a FutureListener so its handled in all cases. - Cancel the timeout whenever the original promise was full-filled. Result: Fixes https://github.com/netty/netty/issues/8013.
233 lines
9.0 KiB
Java
233 lines
9.0 KiB
Java
/*
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* Copyright 2014 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.resolver.dns;
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import io.netty.channel.AddressedEnvelope;
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import io.netty.channel.Channel;
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import io.netty.channel.ChannelFuture;
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import io.netty.channel.ChannelFutureListener;
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import io.netty.channel.ChannelPromise;
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import io.netty.handler.codec.dns.DatagramDnsQuery;
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import io.netty.handler.codec.dns.AbstractDnsOptPseudoRrRecord;
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import io.netty.handler.codec.dns.DnsQuery;
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import io.netty.handler.codec.dns.DnsQuestion;
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import io.netty.handler.codec.dns.DnsRecord;
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import io.netty.handler.codec.dns.DnsResponse;
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import io.netty.handler.codec.dns.DnsSection;
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import io.netty.util.concurrent.Future;
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import io.netty.util.concurrent.FutureListener;
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import io.netty.util.concurrent.GenericFutureListener;
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import io.netty.util.concurrent.Promise;
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import io.netty.util.concurrent.ScheduledFuture;
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import io.netty.util.internal.logging.InternalLogger;
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import io.netty.util.internal.logging.InternalLoggerFactory;
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import java.net.InetSocketAddress;
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import java.util.concurrent.TimeUnit;
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import static io.netty.util.internal.ObjectUtil.checkNotNull;
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final class DnsQueryContext implements FutureListener<AddressedEnvelope<DnsResponse, InetSocketAddress>> {
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private static final InternalLogger logger = InternalLoggerFactory.getInstance(DnsQueryContext.class);
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private final DnsNameResolver parent;
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private final Promise<AddressedEnvelope<DnsResponse, InetSocketAddress>> promise;
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private final int id;
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private final DnsQuestion question;
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private final DnsRecord[] additionals;
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private final DnsRecord optResource;
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private final InetSocketAddress nameServerAddr;
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private final boolean recursionDesired;
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private volatile ScheduledFuture<?> timeoutFuture;
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DnsQueryContext(DnsNameResolver parent,
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InetSocketAddress nameServerAddr,
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DnsQuestion question,
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DnsRecord[] additionals,
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Promise<AddressedEnvelope<DnsResponse, InetSocketAddress>> promise) {
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this.parent = checkNotNull(parent, "parent");
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this.nameServerAddr = checkNotNull(nameServerAddr, "nameServerAddr");
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this.question = checkNotNull(question, "question");
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this.additionals = checkNotNull(additionals, "additionals");
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this.promise = checkNotNull(promise, "promise");
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recursionDesired = parent.isRecursionDesired();
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id = parent.queryContextManager.add(this);
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// Ensure we remove the id from the QueryContextManager once the query completes.
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promise.addListener(this);
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if (parent.isOptResourceEnabled()) {
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optResource = new AbstractDnsOptPseudoRrRecord(parent.maxPayloadSize(), 0, 0) {
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// We may want to remove this in the future and let the user just specify the opt record in the query.
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};
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} else {
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optResource = null;
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}
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}
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InetSocketAddress nameServerAddr() {
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return nameServerAddr;
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}
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DnsQuestion question() {
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return question;
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}
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void query(ChannelPromise writePromise) {
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final DnsQuestion question = question();
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final InetSocketAddress nameServerAddr = nameServerAddr();
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final DatagramDnsQuery query = new DatagramDnsQuery(null, nameServerAddr, id);
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query.setRecursionDesired(recursionDesired);
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query.addRecord(DnsSection.QUESTION, question);
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for (DnsRecord record: additionals) {
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query.addRecord(DnsSection.ADDITIONAL, record);
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}
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if (optResource != null) {
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query.addRecord(DnsSection.ADDITIONAL, optResource);
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}
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if (logger.isDebugEnabled()) {
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logger.debug("{} WRITE: [{}: {}], {}", parent.ch, id, nameServerAddr, question);
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}
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sendQuery(query, writePromise);
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}
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private void sendQuery(final DnsQuery query, final ChannelPromise writePromise) {
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if (parent.channelFuture.isDone()) {
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writeQuery(query, writePromise);
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} else {
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parent.channelFuture.addListener(new GenericFutureListener<Future<? super Channel>>() {
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@Override
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public void operationComplete(Future<? super Channel> future) {
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if (future.isSuccess()) {
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writeQuery(query, writePromise);
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} else {
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Throwable cause = future.cause();
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promise.tryFailure(cause);
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writePromise.setFailure(cause);
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}
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}
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});
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}
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}
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private void writeQuery(final DnsQuery query, final ChannelPromise writePromise) {
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final ChannelFuture writeFuture = parent.ch.writeAndFlush(query, writePromise);
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if (writeFuture.isDone()) {
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onQueryWriteCompletion(writeFuture);
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} else {
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writeFuture.addListener(new ChannelFutureListener() {
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@Override
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public void operationComplete(ChannelFuture future) {
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onQueryWriteCompletion(writeFuture);
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}
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});
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}
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}
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private void onQueryWriteCompletion(ChannelFuture writeFuture) {
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if (!writeFuture.isSuccess()) {
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setFailure("failed to send a query", writeFuture.cause());
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return;
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}
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// Schedule a query timeout task if necessary.
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final long queryTimeoutMillis = parent.queryTimeoutMillis();
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if (queryTimeoutMillis > 0) {
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timeoutFuture = parent.ch.eventLoop().schedule(new Runnable() {
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@Override
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public void run() {
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if (promise.isDone()) {
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// Received a response before the query times out.
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return;
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}
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setFailure("query timed out after " + queryTimeoutMillis + " milliseconds", null);
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}
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}, queryTimeoutMillis, TimeUnit.MILLISECONDS);
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}
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}
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void finish(AddressedEnvelope<? extends DnsResponse, InetSocketAddress> envelope) {
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final DnsResponse res = envelope.content();
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if (res.count(DnsSection.QUESTION) != 1) {
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logger.warn("Received a DNS response with invalid number of questions: {}", envelope);
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return;
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}
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if (!question().equals(res.recordAt(DnsSection.QUESTION))) {
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logger.warn("Received a mismatching DNS response: {}", envelope);
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return;
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}
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setSuccess(envelope);
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}
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private void setSuccess(AddressedEnvelope<? extends DnsResponse, InetSocketAddress> envelope) {
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Promise<AddressedEnvelope<DnsResponse, InetSocketAddress>> promise = this.promise;
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@SuppressWarnings("unchecked")
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AddressedEnvelope<DnsResponse, InetSocketAddress> castResponse =
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(AddressedEnvelope<DnsResponse, InetSocketAddress>) envelope.retain();
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if (!promise.trySuccess(castResponse)) {
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// We failed to notify the promise as it was failed before, thus we need to release the envelope
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envelope.release();
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}
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}
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private void setFailure(String message, Throwable cause) {
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final InetSocketAddress nameServerAddr = nameServerAddr();
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final StringBuilder buf = new StringBuilder(message.length() + 64);
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buf.append('[')
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.append(nameServerAddr)
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.append("] ")
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.append(message)
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.append(" (no stack trace available)");
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final DnsNameResolverException e;
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if (cause == null) {
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// This was caused by an timeout so use DnsNameResolverTimeoutException to allow the user to
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// handle it special (like retry the query).
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e = new DnsNameResolverTimeoutException(nameServerAddr, question(), buf.toString());
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} else {
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e = new DnsNameResolverException(nameServerAddr, question(), buf.toString(), cause);
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}
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promise.tryFailure(e);
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}
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@Override
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public void operationComplete(Future<AddressedEnvelope<DnsResponse, InetSocketAddress>> future) {
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// Cancel the timeout task.
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final ScheduledFuture<?> timeoutFuture = this.timeoutFuture;
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if (timeoutFuture != null) {
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this.timeoutFuture = null;
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timeoutFuture.cancel(false);
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}
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// Remove the id from the manager as soon as the query completes. This may be because of success, failure or
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// cancellation
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parent.queryContextManager.remove(nameServerAddr, id);
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}
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}
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