229 lines
8.9 KiB
Java
229 lines
8.9 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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* https://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.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.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 java.util.Objects.requireNonNull;
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abstract 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 = requireNonNull(parent, "parent");
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this.nameServerAddr = requireNonNull(nameServerAddr, "nameServerAddr");
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this.question = requireNonNull(question, "question");
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this.additionals = requireNonNull(additionals, "additionals");
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this.promise = requireNonNull(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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DnsNameResolver parent() {
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return parent;
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}
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protected abstract DnsQuery newQuery(int id);
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protected abstract Channel channel();
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protected abstract String protocol();
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void query(boolean flush, Promise<Void> writePromise) {
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final DnsQuestion question = question();
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final InetSocketAddress nameServerAddr = nameServerAddr();
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final DnsQuery query = newQuery(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: {}, [{}: {}], {}", channel(), protocol(), id, nameServerAddr, question);
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}
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sendQuery(query, flush, writePromise);
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}
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private void sendQuery(final DnsQuery query, final boolean flush, final Promise<Void> writePromise) {
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if (parent.channelFuture.isDone()) {
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writeQuery(query, flush, writePromise);
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} else {
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parent.channelFuture.addListener(future -> {
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if (future.isSuccess()) {
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// If the query is done in a late fashion (as the channel was not ready yet) we always flush
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// to ensure we did not race with a previous flush() that was done when the Channel was not
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// ready yet.
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writeQuery(query, true, 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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private void writeQuery(final DnsQuery query, final boolean flush, final Promise<Void> writePromise) {
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final Future<Void> writeFuture = flush ? channel().writeAndFlush(query) :
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channel().write(query);
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if (writeFuture.isDone()) {
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onQueryWriteCompletion(writeFuture, writePromise);
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} else {
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writeFuture.addListener(future ->
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onQueryWriteCompletion(future, writePromise));
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}
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}
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private void onQueryWriteCompletion(Future<? extends Void> writeFuture, Promise<Void> writePromise) {
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if (!writeFuture.isSuccess()) {
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writePromise.setFailure(writeFuture.cause());
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tryFailure("failed to send a query via " + protocol(), writeFuture.cause(), false);
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return;
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}
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writePromise.setSuccess(null);
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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.executor().schedule(() -> {
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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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tryFailure("query via " + protocol() + " timed out after " +
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queryTimeoutMillis + " milliseconds", null, true);
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}, queryTimeoutMillis, TimeUnit.MILLISECONDS);
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}
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}
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/**
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* Takes ownership of passed envelope
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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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} else if (!question().equals(res.recordAt(DnsSection.QUESTION))) {
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logger.warn("Received a mismatching DNS response: {}", envelope);
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} else if (trySuccess(envelope)) {
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return; // Ownership transferred, don't release
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}
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envelope.release();
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}
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@SuppressWarnings("unchecked")
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private boolean trySuccess(AddressedEnvelope<? extends DnsResponse, InetSocketAddress> envelope) {
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return promise.trySuccess((AddressedEnvelope<DnsResponse, InetSocketAddress>) envelope);
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}
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boolean tryFailure(String message, Throwable cause, boolean timeout) {
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if (promise.isDone()) {
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return false;
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}
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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 (timeout) {
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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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return promise.tryFailure(e);
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}
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@Override
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public void operationComplete(Future<? extends 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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