bace8a1cce
Motivation: DefaultPromise requires an EventExecutor which provides the thread to notify listeners on and this EventExecutor can never change. We can remove the code that supported the possibility of a changing the executor as this is not possible anymore. Modifications: - Remove constructor which allowed to construct a *Promise without an EventExecutor - Remove extra state - Adjusted SslHandler and ProxyHandler for new code Result: Fixes https://github.com/netty/netty/issues/8517.
460 lines
15 KiB
Java
460 lines
15 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.handler.proxy;
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import static java.util.Objects.requireNonNull;
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import io.netty.channel.Channel;
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import io.netty.channel.ChannelFutureListener;
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import io.netty.channel.ChannelHandler;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.channel.ChannelPromise;
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import io.netty.channel.PendingWriteQueue;
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import io.netty.util.ReferenceCountUtil;
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import io.netty.util.concurrent.DefaultPromise;
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import io.netty.util.concurrent.Future;
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import io.netty.util.concurrent.ImmediateEventExecutor;
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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.SocketAddress;
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import java.nio.channels.ConnectionPendingException;
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import java.util.concurrent.TimeUnit;
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public abstract class ProxyHandler implements ChannelHandler {
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private static final InternalLogger logger = InternalLoggerFactory.getInstance(ProxyHandler.class);
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/**
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* The default connect timeout: 10 seconds.
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*/
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private static final long DEFAULT_CONNECT_TIMEOUT_MILLIS = 10000;
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/**
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* A string that signifies 'no authentication' or 'anonymous'.
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*/
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static final String AUTH_NONE = "none";
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private final SocketAddress proxyAddress;
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private volatile SocketAddress destinationAddress;
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private volatile long connectTimeoutMillis = DEFAULT_CONNECT_TIMEOUT_MILLIS;
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private volatile ChannelHandlerContext ctx;
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private PendingWriteQueue pendingWrites;
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private boolean finished;
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private boolean suppressChannelReadComplete;
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private boolean flushedPrematurely;
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private final Promise<Channel> connectPromise = new LazyPromise();
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private ScheduledFuture<?> connectTimeoutFuture;
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private final ChannelFutureListener writeListener = future -> {
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if (!future.isSuccess()) {
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setConnectFailure(future.cause());
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}
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};
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protected ProxyHandler(SocketAddress proxyAddress) {
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requireNonNull(proxyAddress, "proxyAddress");
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this.proxyAddress = proxyAddress;
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}
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/**
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* Returns the name of the proxy protocol in use.
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*/
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public abstract String protocol();
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/**
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* Returns the name of the authentication scheme in use.
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*/
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public abstract String authScheme();
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/**
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* Returns the address of the proxy server.
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*/
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@SuppressWarnings("unchecked")
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public final <T extends SocketAddress> T proxyAddress() {
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return (T) proxyAddress;
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}
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/**
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* Returns the address of the destination to connect to via the proxy server.
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*/
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@SuppressWarnings("unchecked")
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public final <T extends SocketAddress> T destinationAddress() {
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return (T) destinationAddress;
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}
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/**
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* Returns {@code true} if and only if the connection to the destination has been established successfully.
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*/
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public final boolean isConnected() {
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return connectPromise.isSuccess();
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}
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/**
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* Returns a {@link Future} that is notified when the connection to the destination has been established
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* or the connection attempt has failed.
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*/
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public final Future<Channel> connectFuture() {
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return connectPromise;
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}
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/**
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* Returns the connect timeout in millis. If the connection attempt to the destination does not finish within
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* the timeout, the connection attempt will be failed.
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*/
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public final long connectTimeoutMillis() {
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return connectTimeoutMillis;
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}
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/**
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* Sets the connect timeout in millis. If the connection attempt to the destination does not finish within
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* the timeout, the connection attempt will be failed.
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*/
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public final void setConnectTimeoutMillis(long connectTimeoutMillis) {
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if (connectTimeoutMillis <= 0) {
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connectTimeoutMillis = 0;
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}
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this.connectTimeoutMillis = connectTimeoutMillis;
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}
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@Override
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public final void handlerAdded(ChannelHandlerContext ctx) throws Exception {
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this.ctx = ctx;
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addCodec(ctx);
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if (ctx.channel().isActive()) {
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// channelActive() event has been fired already, which means this.channelActive() will
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// not be invoked. We have to initialize here instead.
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sendInitialMessage(ctx);
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} else {
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// channelActive() event has not been fired yet. this.channelOpen() will be invoked
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// and initialization will occur there.
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}
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}
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/**
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* Adds the codec handlers required to communicate with the proxy server.
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*/
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protected abstract void addCodec(ChannelHandlerContext ctx) throws Exception;
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/**
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* Removes the encoders added in {@link #addCodec(ChannelHandlerContext)}.
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*/
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protected abstract void removeEncoder(ChannelHandlerContext ctx) throws Exception;
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/**
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* Removes the decoders added in {@link #addCodec(ChannelHandlerContext)}.
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*/
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protected abstract void removeDecoder(ChannelHandlerContext ctx) throws Exception;
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@Override
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public final void connect(
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ChannelHandlerContext ctx, SocketAddress remoteAddress, SocketAddress localAddress,
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ChannelPromise promise) throws Exception {
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if (destinationAddress != null) {
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promise.setFailure(new ConnectionPendingException());
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return;
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}
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destinationAddress = remoteAddress;
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ctx.connect(proxyAddress, localAddress, promise);
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}
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@Override
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public final void channelActive(ChannelHandlerContext ctx) throws Exception {
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sendInitialMessage(ctx);
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ctx.fireChannelActive();
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}
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/**
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* Sends the initial message to be sent to the proxy server. This method also starts a timeout task which marks
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* the {@link #connectPromise} as failure if the connection attempt does not success within the timeout.
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*/
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private void sendInitialMessage(final ChannelHandlerContext ctx) throws Exception {
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final long connectTimeoutMillis = this.connectTimeoutMillis;
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if (connectTimeoutMillis > 0) {
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connectTimeoutFuture = ctx.executor().schedule(() -> {
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if (!connectPromise.isDone()) {
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setConnectFailure(new ProxyConnectException(exceptionMessage("timeout")));
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}
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}, connectTimeoutMillis, TimeUnit.MILLISECONDS);
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}
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final Object initialMessage = newInitialMessage(ctx);
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if (initialMessage != null) {
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sendToProxyServer(initialMessage);
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}
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readIfNeeded(ctx);
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}
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/**
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* Returns a new message that is sent at first time when the connection to the proxy server has been established.
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*
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* @return the initial message, or {@code null} if the proxy server is expected to send the first message instead
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*/
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protected abstract Object newInitialMessage(ChannelHandlerContext ctx) throws Exception;
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/**
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* Sends the specified message to the proxy server. Use this method to send a response to the proxy server in
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* {@link #handleResponse(ChannelHandlerContext, Object)}.
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*/
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protected final void sendToProxyServer(Object msg) {
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ctx.writeAndFlush(msg).addListener(writeListener);
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}
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@Override
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public final void channelInactive(ChannelHandlerContext ctx) throws Exception {
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if (finished) {
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ctx.fireChannelInactive();
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} else {
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// Disconnected before connected to the destination.
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setConnectFailure(new ProxyConnectException(exceptionMessage("disconnected")));
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}
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}
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@Override
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public final void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
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if (finished) {
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ctx.fireExceptionCaught(cause);
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} else {
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// Exception was raised before the connection attempt is finished.
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setConnectFailure(cause);
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}
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}
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@Override
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public final void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
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if (finished) {
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// Received a message after the connection has been established; pass through.
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suppressChannelReadComplete = false;
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ctx.fireChannelRead(msg);
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} else {
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suppressChannelReadComplete = true;
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Throwable cause = null;
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try {
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boolean done = handleResponse(ctx, msg);
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if (done) {
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setConnectSuccess();
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}
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} catch (Throwable t) {
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cause = t;
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} finally {
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ReferenceCountUtil.release(msg);
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if (cause != null) {
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setConnectFailure(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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* Handles the message received from the proxy server.
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*
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* @return {@code true} if the connection to the destination has been established,
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* {@code false} if the connection to the destination has not been established and more messages are
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* expected from the proxy server
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*/
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protected abstract boolean handleResponse(ChannelHandlerContext ctx, Object response) throws Exception;
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private void setConnectSuccess() {
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finished = true;
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cancelConnectTimeoutFuture();
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if (!connectPromise.isDone()) {
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boolean removedCodec = true;
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removedCodec &= safeRemoveEncoder();
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ctx.fireUserEventTriggered(
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new ProxyConnectionEvent(protocol(), authScheme(), proxyAddress, destinationAddress));
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removedCodec &= safeRemoveDecoder();
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if (removedCodec) {
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writePendingWrites();
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if (flushedPrematurely) {
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ctx.flush();
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}
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connectPromise.trySuccess(ctx.channel());
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} else {
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// We are at inconsistent state because we failed to remove all codec handlers.
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Exception cause = new ProxyConnectException(
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"failed to remove all codec handlers added by the proxy handler; bug?");
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failPendingWritesAndClose(cause);
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}
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}
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}
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private boolean safeRemoveDecoder() {
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try {
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removeDecoder(ctx);
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return true;
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} catch (Exception e) {
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logger.warn("Failed to remove proxy decoders:", e);
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}
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return false;
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}
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private boolean safeRemoveEncoder() {
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try {
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removeEncoder(ctx);
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return true;
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} catch (Exception e) {
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logger.warn("Failed to remove proxy encoders:", e);
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}
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return false;
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}
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private void setConnectFailure(Throwable cause) {
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finished = true;
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cancelConnectTimeoutFuture();
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if (!connectPromise.isDone()) {
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if (!(cause instanceof ProxyConnectException)) {
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cause = new ProxyConnectException(
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exceptionMessage(cause.toString()), cause);
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}
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safeRemoveDecoder();
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safeRemoveEncoder();
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failPendingWritesAndClose(cause);
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}
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}
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private void failPendingWritesAndClose(Throwable cause) {
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failPendingWrites(cause);
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connectPromise.tryFailure(cause);
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ctx.fireExceptionCaught(cause);
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ctx.close();
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}
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private void cancelConnectTimeoutFuture() {
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if (connectTimeoutFuture != null) {
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connectTimeoutFuture.cancel(false);
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connectTimeoutFuture = null;
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}
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}
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/**
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* Decorates the specified exception message with the common information such as the current protocol,
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* authentication scheme, proxy address, and destination address.
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*/
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protected final String exceptionMessage(String msg) {
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if (msg == null) {
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msg = "";
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}
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StringBuilder buf = new StringBuilder(128 + msg.length())
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.append(protocol())
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.append(", ")
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.append(authScheme())
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.append(", ")
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.append(proxyAddress)
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.append(" => ")
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.append(destinationAddress);
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if (!msg.isEmpty()) {
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buf.append(", ").append(msg);
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}
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return buf.toString();
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}
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@Override
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public final void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
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if (suppressChannelReadComplete) {
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suppressChannelReadComplete = false;
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readIfNeeded(ctx);
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} else {
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ctx.fireChannelReadComplete();
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}
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}
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@Override
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public final void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
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if (finished) {
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writePendingWrites();
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ctx.write(msg, promise);
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} else {
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addPendingWrite(ctx, msg, promise);
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}
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}
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@Override
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public final void flush(ChannelHandlerContext ctx) throws Exception {
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if (finished) {
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writePendingWrites();
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ctx.flush();
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} else {
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flushedPrematurely = true;
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}
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}
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private static void readIfNeeded(ChannelHandlerContext ctx) {
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if (!ctx.channel().config().isAutoRead()) {
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ctx.read();
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}
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}
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private void writePendingWrites() {
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if (pendingWrites != null) {
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pendingWrites.removeAndWriteAll();
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pendingWrites = null;
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}
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}
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private void failPendingWrites(Throwable cause) {
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if (pendingWrites != null) {
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pendingWrites.removeAndFailAll(cause);
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pendingWrites = null;
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}
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}
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private void addPendingWrite(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) {
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PendingWriteQueue pendingWrites = this.pendingWrites;
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if (pendingWrites == null) {
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this.pendingWrites = pendingWrites = new PendingWriteQueue(ctx);
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}
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pendingWrites.add(msg, promise);
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}
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private final class LazyPromise extends DefaultPromise<Channel> {
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LazyPromise() {
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super(ImmediateEventExecutor.INSTANCE);
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}
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@Override
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protected void checkDeadLock() {
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if (ctx == null) {
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// If ctx is null the handlerAdded(...) callback was not called yet.
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return;
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}
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checkDeadLock(ctx.executor());
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}
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}
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}
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