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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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/*
 * Copyright 2012 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.handler.ssl;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.netty.buffer.ByteBufUtil;
import io.netty.buffer.CompositeByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.AbstractCoalescingBufferQueue;
import io.netty.channel.Channel;
import io.netty.channel.ChannelConfig;
import io.netty.channel.ChannelException;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandler;
import io.netty.channel.ChannelOption;
import io.netty.channel.ChannelOutboundBuffer;
import io.netty.channel.ChannelOutboundHandler;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.ChannelPromise;
import io.netty.channel.unix.UnixChannel;
import io.netty.handler.codec.ByteToMessageDecoder;
import io.netty.handler.codec.DecoderException;
import io.netty.handler.codec.UnsupportedMessageTypeException;
import io.netty.util.ReferenceCountUtil;
import io.netty.util.concurrent.DefaultPromise;
import io.netty.util.concurrent.EventExecutor;
import io.netty.util.concurrent.Future;
import io.netty.util.concurrent.FutureListener;
import io.netty.util.concurrent.ImmediateExecutor;
import io.netty.util.concurrent.Promise;
import io.netty.util.concurrent.PromiseNotifier;
import io.netty.util.internal.ObjectUtil;
import io.netty.util.internal.PlatformDependent;
import io.netty.util.internal.UnstableApi;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;

import java.io.IOException;
import java.net.SocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.DatagramChannel;
import java.nio.channels.SocketChannel;
import java.util.List;
import java.util.concurrent.Executor;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.regex.Pattern;

import javax.net.ssl.SSLEngine;
import javax.net.ssl.SSLEngineResult;
import javax.net.ssl.SSLEngineResult.HandshakeStatus;
import javax.net.ssl.SSLEngineResult.Status;
import javax.net.ssl.SSLException;
import javax.net.ssl.SSLHandshakeException;
import javax.net.ssl.SSLSession;

import static io.netty.buffer.ByteBufUtil.ensureWritableSuccess;
import static io.netty.handler.ssl.SslUtils.getEncryptedPacketLength;
import static io.netty.util.internal.ObjectUtil.checkNotNull;
import static io.netty.util.internal.ObjectUtil.checkPositiveOrZero;

/**
 * Adds SSL
 * · TLS and StartTLS support to a {@link Channel}.  Please refer
 * to the "SecureChat" example in the distribution or the web
 * site for the detailed usage.
 *
 * 
Beginning the handshake

 * 

 * Beside using the handshake {@link ChannelFuture} to get notified about the completion of the handshake it's
 * also possible to detect it by implement the
 * {@link ChannelInboundHandler#userEventTriggered(ChannelHandlerContext, Object)}
 * method and check for a {@link SslHandshakeCompletionEvent}.
 *
 * 
Handshake

 * 

 * The handshake will be automatically issued for you once the {@link Channel} is active and
 * {@link SSLEngine#getUseClientMode()} returns {@code true}.
 * So no need to bother with it by your self.
 *
 * 
Closing the session

 * 

 * To close the SSL session, the {@link #closeOutbound()} method should be
 * called to send the {@code close_notify} message to the remote peer. One
 * exception is when you close the {@link Channel} - {@link SslHandler}
 * intercepts the close request and send the {@code close_notify} message
 * before the channel closure automatically.  Once the SSL session is closed,
 * it is not reusable, and consequently you should create a new
 * {@link SslHandler} with a new {@link SSLEngine} as explained in the
 * following section.
 *
 * 
Restarting the session

 * 

 * To restart the SSL session, you must remove the existing closed
 * {@link SslHandler} from the {@link ChannelPipeline}, insert a new
 * {@link SslHandler} with a new {@link SSLEngine} into the pipeline,
 * and start the handshake process as described in the first section.
 *
 * 
Implementing StartTLS

 * 

 * StartTLS is the
 * communication pattern that secures the wire in the middle of the plaintext
 * connection.  Please note that it is different from SSL · TLS, that
 * secures the wire from the beginning of the connection.  Typically, StartTLS
 * is composed of three steps:
 * 
    
 * 
  1. Client sends a StartTLS request to server.
    2. 
 * 
  2. Server sends a StartTLS response to client.
    3. 
 * 
  3. Client begins SSL handshake.
    4. 
 * 

 * If you implement a server, you need to:
 * 
    
 * 
  1. create a new {@link SslHandler} instance with {@code startTls} flag set
 *     to {@code true},
    2. 
 * 
  2. insert the {@link SslHandler} to the {@link ChannelPipeline}, and
    3. 
 * 
  3. write a StartTLS response.
    4. 
 * 

 * Please note that you must insert {@link SslHandler} before sending
 * the StartTLS response.  Otherwise the client can send begin SSL handshake
 * before {@link SslHandler} is inserted to the {@link ChannelPipeline}, causing
 * data corruption.
 * 

 * The client-side implementation is much simpler.
 * 
    
 * 
  1. Write a StartTLS request,
    2. 
 * 
  2. wait for the StartTLS response,
    3. 
 * 
  3. create a new {@link SslHandler} instance with {@code startTls} flag set
 *     to {@code false},
    4. 
 * 
  4. insert the {@link SslHandler} to the {@link ChannelPipeline}, and
    5. 
 * 
  5. Initiate SSL handshake.
    6. 
 * 

 *
 * 
Known issues

 * 

 * Because of a known issue with the current implementation of the SslEngine that comes
 * with Java it may be possible that you see blocked IO-Threads while a full GC is done.
 * 

 * So if you are affected you can workaround this problem by adjust the cache settings
 * like shown below:
 *
 * 
 *     SslContext context = ...;
 *     context.getServerSessionContext().setSessionCacheSize(someSaneSize);
 *     context.getServerSessionContext().setSessionTime(someSameTimeout);
 * 

 * 

 * What values to use here depends on the nature of your application and should be set
 * based on monitoring and debugging of it.
 * For more details see
 * #832 in our issue tracker.
 */
public class SslHandler extends ByteToMessageDecoder implements ChannelOutboundHandler {
    private static final InternalLogger logger =
            InternalLoggerFactory.getInstance(SslHandler.class);
    private static final Pattern IGNORABLE_CLASS_IN_STACK = Pattern.compile(
            "^.*(?:Socket|Datagram|Sctp|Udt)Channel.*$");
    private static final Pattern IGNORABLE_ERROR_MESSAGE = Pattern.compile(
            "^.*(?:connection.*(?:reset|closed|abort|broken)|broken.*pipe).*$", Pattern.CASE_INSENSITIVE);
    private static final int STATE_SENT_FIRST_MESSAGE = 1;
    private static final int STATE_FLUSHED_BEFORE_HANDSHAKE = 1 << 1;
    private static final int STATE_READ_DURING_HANDSHAKE = 1 << 2;
    private static final int STATE_HANDSHAKE_STARTED = 1 << 3;
    /**
     * Set by wrap*() methods when something is produced.
     * {@link #channelReadComplete(ChannelHandlerContext)} will check this flag, clear it, and call ctx.flush().
     */
    private static final int STATE_NEEDS_FLUSH = 1 << 4;
    private static final int STATE_OUTBOUND_CLOSED = 1 << 5;
    private static final int STATE_CLOSE_NOTIFY = 1 << 6;
    private static final int STATE_PROCESS_TASK = 1 << 7;
    /**
     * This flag is used to determine if we need to call {@link ChannelHandlerContext#read()} to consume more data
     * when {@link ChannelConfig#isAutoRead()} is {@code false}.
     */
    private static final int STATE_FIRE_CHANNEL_READ = 1 << 8;
    private static final int STATE_UNWRAP_REENTRY = 1 << 9;

    /**
     * 2^14 which is the maximum sized plaintext chunk
     * allowed by the TLS RFC.
     */
    private static final int MAX_PLAINTEXT_LENGTH = 16 * 1024;

    private enum SslEngineType {
        TCNATIVE(true, COMPOSITE_CUMULATOR) {
            @Override
            SSLEngineResult unwrap(SslHandler handler, ByteBuf in, int len, ByteBuf out) throws SSLException {
                int nioBufferCount = in.nioBufferCount();
                int writerIndex = out.writerIndex();
                final SSLEngineResult result;
                if (nioBufferCount > 1) {
                    /*
                     * If {@link OpenSslEngine} is in use,
                     * we can use a special {@link OpenSslEngine#unwrap(ByteBuffer[], ByteBuffer[])} method
                     * that accepts multiple {@link ByteBuffer}s without additional memory copies.
                     */
                    ReferenceCountedOpenSslEngine opensslEngine = (ReferenceCountedOpenSslEngine) handler.engine;
                    try {
                        handler.singleBuffer[0] = toByteBuffer(out, writerIndex, out.writableBytes());
                        result = opensslEngine.unwrap(in.nioBuffers(in.readerIndex(), len), handler.singleBuffer);
                    } finally {
                        handler.singleBuffer[0] = null;
                    }
                } else {
                    result = handler.engine.unwrap(toByteBuffer(in, in.readerIndex(), len),
                        toByteBuffer(out, writerIndex, out.writableBytes()));
                }
                out.writerIndex(writerIndex + result.bytesProduced());
                return result;
            }

            @Override
            ByteBuf allocateWrapBuffer(SslHandler handler, ByteBufAllocator allocator,
                                       int pendingBytes, int numComponents) {
                return allocator.directBuffer(((ReferenceCountedOpenSslEngine) handler.engine)
                        .calculateMaxLengthForWrap(pendingBytes, numComponents));
            }

            @Override
            int calculatePendingData(SslHandler handler, int guess) {
                int sslPending = ((ReferenceCountedOpenSslEngine) handler.engine).sslPending();
                return sslPending > 0 ? sslPending : guess;
            }

            @Override
            boolean jdkCompatibilityMode(SSLEngine engine) {
                return ((ReferenceCountedOpenSslEngine) engine).jdkCompatibilityMode;
            }
        },
        CONSCRYPT(true, COMPOSITE_CUMULATOR) {
            @Override
            SSLEngineResult unwrap(SslHandler handler, ByteBuf in, int len, ByteBuf out) throws SSLException {
                int nioBufferCount = in.nioBufferCount();
                int writerIndex = out.writerIndex();
                final SSLEngineResult result;
                if (nioBufferCount > 1) {
                    /*
                     * Use a special unwrap method without additional memory copies.
                     */
                    try {
                        handler.singleBuffer[0] = toByteBuffer(out, writerIndex, out.writableBytes());
                        result = ((ConscryptAlpnSslEngine) handler.engine).unwrap(
                                in.nioBuffers(in.readerIndex(), len),
                                handler.singleBuffer);
                    } finally {
                        handler.singleBuffer[0] = null;
                    }
                } else {
                    result = handler.engine.unwrap(toByteBuffer(in, in.readerIndex(), len),
                            toByteBuffer(out, writerIndex, out.writableBytes()));
                }
                out.writerIndex(writerIndex + result.bytesProduced());
                return result;
            }

            @Override
            ByteBuf allocateWrapBuffer(SslHandler handler, ByteBufAllocator allocator,
                                       int pendingBytes, int numComponents) {
                return allocator.directBuffer(
                        ((ConscryptAlpnSslEngine) handler.engine).calculateOutNetBufSize(pendingBytes, numComponents));
            }

            @Override
            int calculatePendingData(SslHandler handler, int guess) {
                return guess;
            }

            @Override
            boolean jdkCompatibilityMode(SSLEngine engine) {
                return true;
            }
        },
        JDK(false, MERGE_CUMULATOR) {
            @Override
            SSLEngineResult unwrap(SslHandler handler, ByteBuf in, int len, ByteBuf out) throws SSLException {
                int writerIndex = out.writerIndex();
                ByteBuffer inNioBuffer = toByteBuffer(in, in.readerIndex(), len);
                int position = inNioBuffer.position();
                final SSLEngineResult result = handler.engine.unwrap(inNioBuffer,
                    toByteBuffer(out, writerIndex, out.writableBytes()));
                out.writerIndex(writerIndex + result.bytesProduced());

                // This is a workaround for a bug in Android 5.0. Android 5.0 does not correctly update the
                // SSLEngineResult.bytesConsumed() in some cases and just return 0.
                //
                // See:
                //     - https://android-review.googlesource.com/c/platform/external/conscrypt/+/122080
                //     - https://github.com/netty/netty/issues/7758
                if (result.bytesConsumed() == 0) {
                    int consumed = inNioBuffer.position() - position;
                    if (consumed != result.bytesConsumed()) {
                        // Create a new SSLEngineResult with the correct bytesConsumed().
                        return new SSLEngineResult(
                                result.getStatus(), result.getHandshakeStatus(), consumed, result.bytesProduced());
                    }
                }
                return result;
            }

            @Override
            ByteBuf allocateWrapBuffer(SslHandler handler, ByteBufAllocator allocator,
                                       int pendingBytes, int numComponents) {
                // As for the JDK SSLEngine we always need to allocate buffers of the size required by the SSLEngine
                // (normally ~16KB). This is required even if the amount of data to encrypt is very small. Use heap
                // buffers to reduce the native memory usage.
                //
                // Beside this the JDK SSLEngine also (as of today) will do an extra heap to direct buffer copy
                // if a direct buffer is used as its internals operate on byte[].
                return allocator.heapBuffer(handler.engine.getSession().getPacketBufferSize());
            }

            @Override
            int calculatePendingData(SslHandler handler, int guess) {
                return guess;
            }

            @Override
            boolean jdkCompatibilityMode(SSLEngine engine) {
                return true;
            }
        };

        static SslEngineType forEngine(SSLEngine engine) {
            return engine instanceof ReferenceCountedOpenSslEngine ? TCNATIVE :
                   engine instanceof ConscryptAlpnSslEngine ? CONSCRYPT : JDK;
        }

        SslEngineType(boolean wantsDirectBuffer, Cumulator cumulator) {
            this.wantsDirectBuffer = wantsDirectBuffer;
            this.cumulator = cumulator;
        }

        abstract SSLEngineResult unwrap(SslHandler handler, ByteBuf in, int len, ByteBuf out) throws SSLException;

        abstract int calculatePendingData(SslHandler handler, int guess);

        abstract boolean jdkCompatibilityMode(SSLEngine engine);

        abstract ByteBuf allocateWrapBuffer(SslHandler handler, ByteBufAllocator allocator,
                                            int pendingBytes, int numComponents);

        // BEGIN Platform-dependent flags

        /**
         * {@code true} if and only if {@link SSLEngine} expects a direct buffer and so if a heap buffer
         * is given will make an extra memory copy.
         */
        final boolean wantsDirectBuffer;

        // END Platform-dependent flags

        /**
         * When using JDK {@link SSLEngine}, we use {@link #MERGE_CUMULATOR} because it works only with
         * one {@link ByteBuffer}.
         *
         * When using {@link OpenSslEngine}, we can use {@link #COMPOSITE_CUMULATOR} because it has
         * {@link OpenSslEngine#unwrap(ByteBuffer[], ByteBuffer[])} which works with multiple {@link ByteBuffer}s
         * and which does not need to do extra memory copies.
         */
        final Cumulator cumulator;
    }

    private volatile ChannelHandlerContext ctx;
    private final SSLEngine engine;
    private final SslEngineType engineType;
    private final Executor delegatedTaskExecutor;
    private final boolean jdkCompatibilityMode;

    /**
     * Used if {@link SSLEngine#wrap(ByteBuffer[], ByteBuffer)} and {@link SSLEngine#unwrap(ByteBuffer, ByteBuffer[])}
     * should be called with a {@link ByteBuf} that is only backed by one {@link ByteBuffer} to reduce the object
     * creation.
     */
    private final ByteBuffer[] singleBuffer = new ByteBuffer[1];

    private final boolean startTls;

    private final SslTasksRunner sslTaskRunnerForUnwrap = new SslTasksRunner(true);
    private final SslTasksRunner sslTaskRunner = new SslTasksRunner(false);

    private SslHandlerCoalescingBufferQueue pendingUnencryptedWrites;
    private Promise handshakePromise = new LazyChannelPromise();
    private final LazyChannelPromise sslClosePromise = new LazyChannelPromise();

    private int packetLength;
    private short state;

    private volatile long handshakeTimeoutMillis = 10000;
    private volatile long closeNotifyFlushTimeoutMillis = 3000;
    private volatile long closeNotifyReadTimeoutMillis;
    volatile int wrapDataSize = MAX_PLAINTEXT_LENGTH;

    /**
     * Creates a new instance which runs all delegated tasks directly on the {@link EventExecutor}.
     *
     * @param engine  the {@link SSLEngine} this handler will use
     */
    public SslHandler(SSLEngine engine) {
        this(engine, false);
    }

    /**
     * Creates a new instance which runs all delegated tasks directly on the {@link EventExecutor}.
     *
     * @param engine    the {@link SSLEngine} this handler will use
     * @param startTls  {@code true} if the first write request shouldn't be
     *                  encrypted by the {@link SSLEngine}
     */
    public SslHandler(SSLEngine engine, boolean startTls) {
        this(engine, startTls, ImmediateExecutor.INSTANCE);
    }

    /**
     * Creates a new instance.
     *
     * @param engine  the {@link SSLEngine} this handler will use
     * @param delegatedTaskExecutor the {@link Executor} that will be used to execute tasks that are returned by
     *                              {@link SSLEngine#getDelegatedTask()}.
     */
    public SslHandler(SSLEngine engine, Executor delegatedTaskExecutor) {
        this(engine, false, delegatedTaskExecutor);
    }

    /**
     * Creates a new instance.
     *
     * @param engine  the {@link SSLEngine} this handler will use
     * @param startTls  {@code true} if the first write request shouldn't be
     *                  encrypted by the {@link SSLEngine}
     * @param delegatedTaskExecutor the {@link Executor} that will be used to execute tasks that are returned by
     *                              {@link SSLEngine#getDelegatedTask()}.
     */
    public SslHandler(SSLEngine engine, boolean startTls, Executor delegatedTaskExecutor) {
        this.engine = ObjectUtil.checkNotNull(engine, "engine");
        this.delegatedTaskExecutor = ObjectUtil.checkNotNull(delegatedTaskExecutor, "delegatedTaskExecutor");
        engineType = SslEngineType.forEngine(engine);
        this.startTls = startTls;
        this.jdkCompatibilityMode = engineType.jdkCompatibilityMode(engine);
        setCumulator(engineType.cumulator);
    }

    public long getHandshakeTimeoutMillis() {
        return handshakeTimeoutMillis;
    }

    public void setHandshakeTimeout(long handshakeTimeout, TimeUnit unit) {
        checkNotNull(unit, "unit");
        setHandshakeTimeoutMillis(unit.toMillis(handshakeTimeout));
    }

    public void setHandshakeTimeoutMillis(long handshakeTimeoutMillis) {
        this.handshakeTimeoutMillis = checkPositiveOrZero(handshakeTimeoutMillis, "handshakeTimeoutMillis");
    }

    /**
     * Sets the number of bytes to pass to each {@link SSLEngine#wrap(ByteBuffer[], int, int, ByteBuffer)} call.
     * 

     * This value will partition data which is passed to write
     * {@link #write(ChannelHandlerContext, Object, ChannelPromise)}. The partitioning will work as follows:
     * 
    
     * 
  • If {@code wrapDataSize <= 0} then we will write each data chunk as is.
    • 
     * 
  • If {@code wrapDataSize > data size} then we will attempt to aggregate multiple data chunks together.
    • 
     * 
  • If {@code wrapDataSize > data size}  Else if {@code wrapDataSize <= data size} then we will divide the data
     * into chunks of {@code wrapDataSize} when writing.
    • 
     * 

     * 

     * If the {@link SSLEngine} doesn't support a gather wrap operation (e.g. {@link SslProvider#OPENSSL}) then
     * aggregating data before wrapping can help reduce the ratio between TLS overhead vs data payload which will lead
     * to better goodput. Writing fixed chunks of data can also help target the underlying transport's (e.g. TCP)
     * frame size. Under lossy/congested network conditions this may help the peer get full TLS packets earlier and
     * be able to do work sooner, as opposed to waiting for the all the pieces of the TLS packet to arrive.
     * @param wrapDataSize the number of bytes which will be passed to each
     *      {@link SSLEngine#wrap(ByteBuffer[], int, int, ByteBuffer)} call.
     */
    @UnstableApi
    public final void setWrapDataSize(int wrapDataSize) {
        this.wrapDataSize = wrapDataSize;
    }

    /**
     * @deprecated use {@link #getCloseNotifyFlushTimeoutMillis()}
     */
    @Deprecated
    public long getCloseNotifyTimeoutMillis() {
        return getCloseNotifyFlushTimeoutMillis();
    }

    /**
     * @deprecated use {@link #setCloseNotifyFlushTimeout(long, TimeUnit)}
     */
    @Deprecated
    public void setCloseNotifyTimeout(long closeNotifyTimeout, TimeUnit unit) {
        setCloseNotifyFlushTimeout(closeNotifyTimeout, unit);
    }

    /**
     * @deprecated use {@link #setCloseNotifyFlushTimeoutMillis(long)}
     */
    @Deprecated
    public void setCloseNotifyTimeoutMillis(long closeNotifyFlushTimeoutMillis) {
        setCloseNotifyFlushTimeoutMillis(closeNotifyFlushTimeoutMillis);
    }

    /**
     * Gets the timeout for flushing the close_notify that was triggered by closing the
     * {@link Channel}. If the close_notify was not flushed in the given timeout the {@link Channel} will be closed
     * forcibly.
     */
    public final long getCloseNotifyFlushTimeoutMillis() {
        return closeNotifyFlushTimeoutMillis;
    }

    /**
     * Sets the timeout for flushing the close_notify that was triggered by closing the
     * {@link Channel}. If the close_notify was not flushed in the given timeout the {@link Channel} will be closed
     * forcibly.
     */
    public final void setCloseNotifyFlushTimeout(long closeNotifyFlushTimeout, TimeUnit unit) {
        setCloseNotifyFlushTimeoutMillis(unit.toMillis(closeNotifyFlushTimeout));
    }

    /**
     * See {@link #setCloseNotifyFlushTimeout(long, TimeUnit)}.
     */
    public final void setCloseNotifyFlushTimeoutMillis(long closeNotifyFlushTimeoutMillis) {
        this.closeNotifyFlushTimeoutMillis = checkPositiveOrZero(closeNotifyFlushTimeoutMillis,
                "closeNotifyFlushTimeoutMillis");
    }

    /**
     * Gets the timeout (in ms) for receiving the response for the close_notify that was triggered by closing the
     * {@link Channel}. This timeout starts after the close_notify message was successfully written to the
     * remote peer. Use {@code 0} to directly close the {@link Channel} and not wait for the response.
     */
    public final long getCloseNotifyReadTimeoutMillis() {
        return closeNotifyReadTimeoutMillis;
    }

    /**
     * Sets the timeout  for receiving the response for the close_notify that was triggered by closing the
     * {@link Channel}. This timeout starts after the close_notify message was successfully written to the
     * remote peer. Use {@code 0} to directly close the {@link Channel} and not wait for the response.
     */
    public final void setCloseNotifyReadTimeout(long closeNotifyReadTimeout, TimeUnit unit) {
        setCloseNotifyReadTimeoutMillis(unit.toMillis(closeNotifyReadTimeout));
    }

    /**
     * See {@link #setCloseNotifyReadTimeout(long, TimeUnit)}.
     */
    public final void setCloseNotifyReadTimeoutMillis(long closeNotifyReadTimeoutMillis) {
        this.closeNotifyReadTimeoutMillis = checkPositiveOrZero(closeNotifyReadTimeoutMillis,
                "closeNotifyReadTimeoutMillis");
    }

    /**
     * Returns the {@link SSLEngine} which is used by this handler.
     */
    public SSLEngine engine() {
        return engine;
    }

    /**
     * Returns the name of the current application-level protocol.
     *
     * @return the protocol name or {@code null} if application-level protocol has not been negotiated
     */
    public String applicationProtocol() {
        SSLEngine engine = engine();
        if (!(engine instanceof ApplicationProtocolAccessor)) {
            return null;
        }

        return ((ApplicationProtocolAccessor) engine).getNegotiatedApplicationProtocol();
    }

    /**
     * Returns a {@link Future} that will get notified once the current TLS handshake completes.
     *
     * @return the {@link Future} for the initial TLS handshake if {@link #renegotiate()} was not invoked.
     *         The {@link Future} for the most recent {@linkplain #renegotiate() TLS renegotiation} otherwise.
     */
    public Future handshakeFuture() {
        return handshakePromise;
    }

    /**
     * Use {@link #closeOutbound()}
     */
    @Deprecated
    public ChannelFuture close() {
        return closeOutbound();
    }

    /**
     * Use {@link #closeOutbound(ChannelPromise)}
     */
    @Deprecated
    public ChannelFuture close(ChannelPromise promise) {
        return closeOutbound(promise);
    }

    /**
     * Sends an SSL {@code close_notify} message to the specified channel and
     * destroys the underlying {@link SSLEngine}. This will not close the underlying
     * {@link Channel}. If you want to also close the {@link Channel} use {@link Channel#close()} or
     * {@link ChannelHandlerContext#close()}
     */
    public ChannelFuture closeOutbound() {
        return closeOutbound(ctx.newPromise());
    }

    /**
     * Sends an SSL {@code close_notify} message to the specified channel and
     * destroys the underlying {@link SSLEngine}. This will not close the underlying
     * {@link Channel}. If you want to also close the {@link Channel} use {@link Channel#close()} or
     * {@link ChannelHandlerContext#close()}
     */
    public ChannelFuture closeOutbound(final ChannelPromise promise) {
        final ChannelHandlerContext ctx = this.ctx;
        if (ctx.executor().inEventLoop()) {
            closeOutbound0(promise);
        } else {
            ctx.executor().execute(new Runnable() {
                @Override
                public void run() {
                    closeOutbound0(promise);
                }
            });
        }
        return promise;
    }

    private void closeOutbound0(ChannelPromise promise) {
        setState(STATE_OUTBOUND_CLOSED);
        engine.closeOutbound();
        try {
            flush(ctx, promise);
        } catch (Exception e) {
            if (!promise.tryFailure(e)) {
                logger.warn("{} flush() raised a masked exception.", ctx.channel(), e);
            }
        }
    }

    /**
     * Return the {@link Future} that will get notified if the inbound of the {@link SSLEngine} is closed.
     *
     * This method will return the same {@link Future} all the time.
     *
     * @see SSLEngine
     */
    public Future sslCloseFuture() {
        return sslClosePromise;
    }

    @Override
    public void handlerRemoved0(ChannelHandlerContext ctx) throws Exception {
        try {
            if (pendingUnencryptedWrites != null && !pendingUnencryptedWrites.isEmpty()) {
                // Check if queue is not empty first because create a new ChannelException is expensive
                pendingUnencryptedWrites.releaseAndFailAll(ctx,
                  new ChannelException("Pending write on removal of SslHandler"));
            }
            pendingUnencryptedWrites = null;

            SSLException cause = null;

            // If the handshake or SSLEngine closure is not done yet we should fail corresponding promise and
            // notify the rest of the
            // pipeline.
            if (!handshakePromise.isDone()) {
                cause = new SSLHandshakeException("SslHandler removed before handshake completed");
                if (handshakePromise.tryFailure(cause)) {
                    ctx.fireUserEventTriggered(new SslHandshakeCompletionEvent(cause));
                }
            }
            if (!sslClosePromise.isDone()) {
                if (cause == null) {
                    cause = new SSLException("SslHandler removed before SSLEngine was closed");
                }
                notifyClosePromise(cause);
            }
        } finally {
            ReferenceCountUtil.release(engine);
        }
    }

    @Override
    public void bind(ChannelHandlerContext ctx, SocketAddress localAddress, ChannelPromise promise) throws Exception {
        ctx.bind(localAddress, promise);
    }

    @Override
    public void connect(ChannelHandlerContext ctx, SocketAddress remoteAddress, SocketAddress localAddress,
                        ChannelPromise promise) throws Exception {
        ctx.connect(remoteAddress, localAddress, promise);
    }

    @Override
    public void deregister(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception {
        ctx.deregister(promise);
    }

    @Override
    public void disconnect(final ChannelHandlerContext ctx,
                           final ChannelPromise promise) throws Exception {
        closeOutboundAndChannel(ctx, promise, true);
    }

    @Override
    public void close(final ChannelHandlerContext ctx,
                      final ChannelPromise promise) throws Exception {
        closeOutboundAndChannel(ctx, promise, false);
    }

    @Override
    public void read(ChannelHandlerContext ctx) throws Exception {
        if (!handshakePromise.isDone()) {
            setState(STATE_READ_DURING_HANDSHAKE);
        }

        ctx.read();
    }

    private static IllegalStateException newPendingWritesNullException() {
        return new IllegalStateException("pendingUnencryptedWrites is null, handlerRemoved0 called?");
    }

    @Override
    public void write(final ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
        if (!(msg instanceof ByteBuf)) {
            UnsupportedMessageTypeException exception = new UnsupportedMessageTypeException(msg, ByteBuf.class);
            ReferenceCountUtil.safeRelease(msg);
            promise.setFailure(exception);
        } else if (pendingUnencryptedWrites == null) {
            ReferenceCountUtil.safeRelease(msg);
            promise.setFailure(newPendingWritesNullException());
        } else {
            pendingUnencryptedWrites.add((ByteBuf) msg, promise);
        }
    }

    @Override
    public void flush(ChannelHandlerContext ctx) throws Exception {
        // Do not encrypt the first write request if this handler is
        // created with startTLS flag turned on.
        if (startTls && !isStateSet(STATE_SENT_FIRST_MESSAGE)) {
            setState(STATE_SENT_FIRST_MESSAGE);
            pendingUnencryptedWrites.writeAndRemoveAll(ctx);
            forceFlush(ctx);
            // Explicit start handshake processing once we send the first message. This will also ensure
            // we will schedule the timeout if needed.
            startHandshakeProcessing(true);
            return;
        }

        if (isStateSet(STATE_PROCESS_TASK)) {
            return;
        }

        try {
            wrapAndFlush(ctx);
        } catch (Throwable cause) {
            setHandshakeFailure(ctx, cause);
            PlatformDependent.throwException(cause);
        }
    }

    private void wrapAndFlush(ChannelHandlerContext ctx) throws SSLException {
        if (pendingUnencryptedWrites.isEmpty()) {
            // It's important to NOT use a voidPromise here as the user
            // may want to add a ChannelFutureListener to the ChannelPromise later.
            //
            // See https://github.com/netty/netty/issues/3364
            pendingUnencryptedWrites.add(Unpooled.EMPTY_BUFFER, ctx.newPromise());
        }
        if (!handshakePromise.isDone()) {
            setState(STATE_FLUSHED_BEFORE_HANDSHAKE);
        }
        try {
            wrap(ctx, false);
        } finally {
            // We may have written some parts of data before an exception was thrown so ensure we always flush.
            // See https://github.com/netty/netty/issues/3900#issuecomment-172481830
            forceFlush(ctx);
        }
    }

    // This method will not call setHandshakeFailure(...) !
    private void wrap(ChannelHandlerContext ctx, boolean inUnwrap) throws SSLException {
        ByteBuf out = null;
        ByteBufAllocator alloc = ctx.alloc();
        try {
            final int wrapDataSize = this.wrapDataSize;
            // Only continue to loop if the handler was not removed in the meantime.
            // See https://github.com/netty/netty/issues/5860
            outer: while (!ctx.isRemoved()) {
                ChannelPromise promise = ctx.newPromise();
                ByteBuf buf = wrapDataSize > 0 ?
                        pendingUnencryptedWrites.remove(alloc, wrapDataSize, promise) :
                        pendingUnencryptedWrites.removeFirst(promise);
                if (buf == null) {
                    break;
                }

                if (out == null) {
                    out = allocateOutNetBuf(ctx, buf.readableBytes(), buf.nioBufferCount());
                }

                SSLEngineResult result = wrap(alloc, engine, buf, out);
                if (buf.isReadable()) {
                    pendingUnencryptedWrites.addFirst(buf, promise);
                    // When we add the buffer/promise pair back we need to be sure we don't complete the promise
                    // later. We only complete the promise if the buffer is completely consumed.
                    promise = null;
                } else {
                    buf.release();
                }

                // We need to write any data before we invoke any methods which may trigger re-entry, otherwise
                // writes may occur out of order and TLS sequencing may be off (e.g. SSLV3_ALERT_BAD_RECORD_MAC).
                if (out.isReadable()) {
                    final ByteBuf b = out;
                    out = null;
                    if (promise != null) {
                        ctx.write(b, promise);
                    } else {
                        ctx.write(b);
                    }
                } else if (promise != null) {
                    ctx.write(Unpooled.EMPTY_BUFFER, promise);
                }
                // else out is not readable we can re-use it and so save an extra allocation

                if (result.getStatus() == Status.CLOSED) {
                    // Make a best effort to preserve any exception that way previously encountered from the handshake
                    // or the transport, else fallback to a general error.
                    Throwable exception = handshakePromise.cause();
                    if (exception == null) {
                        exception = sslClosePromise.cause();
                        if (exception == null) {
                            exception = new SslClosedEngineException("SSLEngine closed already");
                        }
                    }
                    pendingUnencryptedWrites.releaseAndFailAll(ctx, exception);
                    return;
                } else {
                    switch (result.getHandshakeStatus()) {
                        case NEED_TASK:
                            if (!runDelegatedTasks(inUnwrap)) {
                                // We scheduled a task on the delegatingTaskExecutor, so stop processing as we will
                                // resume once the task completes.
                                break outer;
                            }
                            break;
                        case FINISHED:
                        case NOT_HANDSHAKING: // work around for android bug that skips the FINISHED state.
                            setHandshakeSuccess();
                            break;
                        case NEED_WRAP:
                            // If we are expected to wrap again and we produced some data we need to ensure there
                            // is something in the queue to process as otherwise we will not try again before there
                            // was more added. Failing to do so may fail to produce an alert that can be
                            // consumed by the remote peer.
                            if (result.bytesProduced() > 0 && pendingUnencryptedWrites.isEmpty()) {
                                pendingUnencryptedWrites.add(Unpooled.EMPTY_BUFFER);
                            }
                            break;
                        case NEED_UNWRAP:
                            // The underlying engine is starving so we need to feed it with more data.
                            // See https://github.com/netty/netty/pull/5039
                            readIfNeeded(ctx);
                            return;
                        default:
                            throw new IllegalStateException(
                                    "Unknown handshake status: " + result.getHandshakeStatus());
                    }
                }
            }
        } finally {
            if (out != null) {
                out.release();
            }
            if (inUnwrap) {
                setState(STATE_NEEDS_FLUSH);
            }
        }
    }

    /**
     * This method will not call
     * {@link #setHandshakeFailure(ChannelHandlerContext, Throwable, boolean, boolean, boolean)} or
     * {@link #setHandshakeFailure(ChannelHandlerContext, Throwable)}.
     * @return {@code true} if this method ends on {@link SSLEngineResult.HandshakeStatus#NOT_HANDSHAKING}.
     */
    private boolean wrapNonAppData(final ChannelHandlerContext ctx, boolean inUnwrap) throws SSLException {
        ByteBuf out = null;
        ByteBufAllocator alloc = ctx.alloc();
        try {
            // Only continue to loop if the handler was not removed in the meantime.
            // See https://github.com/netty/netty/issues/5860
            outer: while (!ctx.isRemoved()) {
                if (out == null) {
                    // As this is called for the handshake we have no real idea how big the buffer needs to be.
                    // That said 2048 should give us enough room to include everything like ALPN / NPN data.
                    // If this is not enough we will increase the buffer in wrap(...).
                    out = allocateOutNetBuf(ctx, 2048, 1);
                }
                SSLEngineResult result = wrap(alloc, engine, Unpooled.EMPTY_BUFFER, out);
                if (result.bytesProduced() > 0) {
                    ctx.write(out).addListener(new ChannelFutureListener() {
                        @Override
                        public void operationComplete(ChannelFuture future) {
                            Throwable cause = future.cause();
                            if (cause != null) {
                                setHandshakeFailureTransportFailure(ctx, cause);
                            }
                        }
                    });
                    if (inUnwrap) {
                        setState(STATE_NEEDS_FLUSH);
                    }
                    out = null;
                }

                HandshakeStatus status = result.getHandshakeStatus();
                switch (status) {
                    case FINISHED:
                        // We may be here because we read data and discovered the remote peer initiated a renegotiation
                        // and this write is to complete the new handshake. The user may have previously done a
                        // writeAndFlush which wasn't able to wrap data due to needing the pending handshake, so we
                        // attempt to wrap application data here if any is pending.
                        if (setHandshakeSuccess() && inUnwrap && !pendingUnencryptedWrites.isEmpty()) {
                            wrap(ctx, true);
                        }
                        return false;
                    case NEED_TASK:
                        if (!runDelegatedTasks(inUnwrap)) {
                            // We scheduled a task on the delegatingTaskExecutor, so stop processing as we will
                            // resume once the task completes.
                            break outer;
                        }
                        break;
                    case NEED_UNWRAP:
                        if (inUnwrap || unwrapNonAppData(ctx) <= 0) {
                            // If we asked for a wrap, the engine requested an unwrap, and we are in unwrap there is
                            // no use in trying to call wrap again because we have already attempted (or will after we
                            // return) to feed more data to the engine.
                            return false;
                        }
                        break;
                    case NEED_WRAP:
                        break;
                    case NOT_HANDSHAKING:
                        if (setHandshakeSuccess() && inUnwrap && !pendingUnencryptedWrites.isEmpty()) {
                            wrap(ctx, true);
                        }
                        // Workaround for TLS False Start problem reported at:
                        // https://github.com/netty/netty/issues/1108#issuecomment-14266970
                        if (!inUnwrap) {
                            unwrapNonAppData(ctx);
                        }
                        return true;
                    default:
                        throw new IllegalStateException("Unknown handshake status: " + result.getHandshakeStatus());
                }

                // Check if did not produce any bytes and if so break out of the loop, but only if we did not process
                // a task as last action. It's fine to not produce any data as part of executing a task.
                if (result.bytesProduced() == 0 && status != HandshakeStatus.NEED_TASK) {
                    break;
                }

                // It should not consume empty buffers when it is not handshaking
                // Fix for Android, where it was encrypting empty buffers even when not handshaking
                if (result.bytesConsumed() == 0 && result.getHandshakeStatus() == HandshakeStatus.NOT_HANDSHAKING) {
                    break;
                }
            }
        }  finally {
            if (out != null) {
                out.release();
            }
        }
        return false;
    }

    private SSLEngineResult wrap(ByteBufAllocator alloc, SSLEngine engine, ByteBuf in, ByteBuf out)
            throws SSLException {
        ByteBuf newDirectIn = null;
        try {
            int readerIndex = in.readerIndex();
            int readableBytes = in.readableBytes();

            // We will call SslEngine.wrap(ByteBuffer[], ByteBuffer) to allow efficient handling of
            // CompositeByteBuf without force an extra memory copy when CompositeByteBuffer.nioBuffer() is called.
            final ByteBuffer[] in0;
            if (in.isDirect() || !engineType.wantsDirectBuffer) {
                // As CompositeByteBuf.nioBufferCount() can be expensive (as it needs to check all composed ByteBuf
                // to calculate the count) we will just assume a CompositeByteBuf contains more then 1 ByteBuf.
                // The worst that can happen is that we allocate an extra ByteBuffer[] in CompositeByteBuf.nioBuffers()
                // which is better then walking the composed ByteBuf in most cases.
                if (!(in instanceof CompositeByteBuf) && in.nioBufferCount() == 1) {
                    in0 = singleBuffer;
                    // We know its only backed by 1 ByteBuffer so use internalNioBuffer to keep object allocation
                    // to a minimum.
                    in0[0] = in.internalNioBuffer(readerIndex, readableBytes);
                } else {
                    in0 = in.nioBuffers();
                }
            } else {
                // We could even go further here and check if its a CompositeByteBuf and if so try to decompose it and
                // only replace the ByteBuffer that are not direct. At the moment we just will replace the whole
                // CompositeByteBuf to keep the complexity to a minimum
                newDirectIn = alloc.directBuffer(readableBytes);
                newDirectIn.writeBytes(in, readerIndex, readableBytes);
                in0 = singleBuffer;
                in0[0] = newDirectIn.internalNioBuffer(newDirectIn.readerIndex(), readableBytes);
            }

            for (;;) {
                ByteBuffer out0 = out.nioBuffer(out.writerIndex(), out.writableBytes());
                SSLEngineResult result = engine.wrap(in0, out0);
                in.skipBytes(result.bytesConsumed());
                out.writerIndex(out.writerIndex() + result.bytesProduced());

                if (result.getStatus() == Status.BUFFER_OVERFLOW) {
                    out.ensureWritable(engine.getSession().getPacketBufferSize());
                } else {
                    return result;
                }
            }
        } finally {
            // Null out to allow GC of ByteBuffer
            singleBuffer[0] = null;

            if (newDirectIn != null) {
                newDirectIn.release();
            }
        }
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        boolean handshakeFailed = handshakePromise.cause() != null;

        ClosedChannelException exception = new ClosedChannelException();
        // Make sure to release SSLEngine,
        // and notify the handshake future if the connection has been closed during handshake.
        setHandshakeFailure(ctx, exception, !isStateSet(STATE_OUTBOUND_CLOSED), isStateSet(STATE_HANDSHAKE_STARTED),
                false);

        // Ensure we always notify the sslClosePromise as well
        notifyClosePromise(exception);

        try {
            super.channelInactive(ctx);
        } catch (DecoderException e) {
            if (!handshakeFailed || !(e.getCause() instanceof SSLException)) {
                // We only rethrow the exception if the handshake did not fail before channelInactive(...) was called
                // as otherwise this may produce duplicated failures as super.channelInactive(...) will also call
                // channelRead(...).
                //
                // See https://github.com/netty/netty/issues/10119
                throw e;
            }
        }
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        if (ignoreException(cause)) {
            // It is safe to ignore the 'connection reset by peer' or
            // 'broken pipe' error after sending close_notify.
            if (logger.isDebugEnabled()) {
                logger.debug(
                        "{} Swallowing a harmless 'connection reset by peer / broken pipe' error that occurred " +
                        "while writing close_notify in response to the peer's close_notify", ctx.channel(), cause);
            }

            // Close the connection explicitly just in case the transport
            // did not close the connection automatically.
            if (ctx.channel().isActive()) {
                ctx.close();
            }
        } else {
            ctx.fireExceptionCaught(cause);
        }
    }

    /**
     * Checks if the given {@link Throwable} can be ignore and just "swallowed"
     *
     * When an ssl connection is closed a close_notify message is sent.
     * After that the peer also sends close_notify however, it's not mandatory to receive
     * the close_notify. The party who sent the initial close_notify can close the connection immediately
     * then the peer will get connection reset error.
     *
     */
    private boolean ignoreException(Throwable t) {
        if (!(t instanceof SSLException) && t instanceof IOException && sslClosePromise.isDone()) {
            String message = t.getMessage();

            // first try to match connection reset / broke peer based on the regex. This is the fastest way
            // but may fail on different jdk impls or OS's
            if (message != null && IGNORABLE_ERROR_MESSAGE.matcher(message).matches()) {
                return true;
            }

            // Inspect the StackTraceElements to see if it was a connection reset / broken pipe or not
            StackTraceElement[] elements = t.getStackTrace();
            for (StackTraceElement element: elements) {
                String classname = element.getClassName();
                String methodname = element.getMethodName();

                // skip all classes that belong to the io.netty package
                if (classname.startsWith("io.netty.")) {
                    continue;
                }

                // check if the method name is read if not skip it
                if (!"read".equals(methodname)) {
                    continue;
                }

                // This will also match against SocketInputStream which is used by openjdk 7 and maybe
                // also others
                if (IGNORABLE_CLASS_IN_STACK.matcher(classname).matches()) {
                    return true;
                }

                try {
                    // No match by now.. Try to load the class via classloader and inspect it.
                    // This is mainly done as other JDK implementations may differ in name of
                    // the impl.
                    Class clazz = PlatformDependent.getClassLoader(getClass()).loadClass(classname);

                    if (SocketChannel.class.isAssignableFrom(clazz)
                            || DatagramChannel.class.isAssignableFrom(clazz)) {
                        return true;
                    }

                    // also match against SctpChannel via String matching as it may not present.
                    if (PlatformDependent.javaVersion() >= 7
                            && "com.sun.nio.sctp.SctpChannel".equals(clazz.getSuperclass().getName())) {
                        return true;
                    }
                } catch (Throwable cause) {
                    if (logger.isDebugEnabled()) {
                        logger.debug("Unexpected exception while loading class {} classname {}",
                                getClass(), classname, cause);
                    }
                }
            }
        }

        return false;
    }

    /**
     * Returns {@code true} if the given {@link ByteBuf} is encrypted. Be aware that this method
     * will not increase the readerIndex of the given {@link ByteBuf}.
     *
     * @param   buffer
     *                  The {@link ByteBuf} to read from. Be aware that it must have at least 5 bytes to read,
     *                  otherwise it will throw an {@link IllegalArgumentException}.
     * @return encrypted
     *                  {@code true} if the {@link ByteBuf} is encrypted, {@code false} otherwise.
     * @throws IllegalArgumentException
     *                  Is thrown if the given {@link ByteBuf} has not at least 5 bytes to read.
     */
    public static boolean isEncrypted(ByteBuf buffer) {
        if (buffer.readableBytes() < SslUtils.SSL_RECORD_HEADER_LENGTH) {
            throw new IllegalArgumentException(
                    "buffer must have at least " + SslUtils.SSL_RECORD_HEADER_LENGTH + " readable bytes");
        }
        return getEncryptedPacketLength(buffer, buffer.readerIndex()) != SslUtils.NOT_ENCRYPTED;
    }

    private void decodeJdkCompatible(ChannelHandlerContext ctx, ByteBuf in) throws NotSslRecordException {
        int packetLength = this.packetLength;
        // If we calculated the length of the current SSL record before, use that information.
        if (packetLength > 0) {
            if (in.readableBytes() < packetLength) {
                return;
            }
        } else {
            // Get the packet length and wait until we get a packets worth of data to unwrap.
            final int readableBytes = in.readableBytes();
            if (readableBytes < SslUtils.SSL_RECORD_HEADER_LENGTH) {
                return;
            }
            packetLength = getEncryptedPacketLength(in, in.readerIndex());
            if (packetLength == SslUtils.NOT_ENCRYPTED) {
                // Not an SSL/TLS packet
                NotSslRecordException e = new NotSslRecordException(
                        "not an SSL/TLS record: " + ByteBufUtil.hexDump(in));
                in.skipBytes(in.readableBytes());

                // First fail the handshake promise as we may need to have access to the SSLEngine which may
                // be released because the user will remove the SslHandler in an exceptionCaught(...) implementation.
                setHandshakeFailure(ctx, e);

                throw e;
            }
            assert packetLength > 0;
            if (packetLength > readableBytes) {
                // wait until the whole packet can be read
                this.packetLength = packetLength;
                return;
            }
        }

        // Reset the state of this class so we can get the length of the next packet. We assume the entire packet will
        // be consumed by the SSLEngine.
        this.packetLength = 0;
        try {
            final int bytesConsumed = unwrap(ctx, in, packetLength);
            assert bytesConsumed == packetLength || engine.isInboundDone() :
                    "we feed the SSLEngine a packets worth of data: " + packetLength + " but it only consumed: " +
                            bytesConsumed;
        } catch (Throwable cause) {
            handleUnwrapThrowable(ctx, cause);
        }
    }

    private void decodeNonJdkCompatible(ChannelHandlerContext ctx, ByteBuf in) {
        try {
            unwrap(ctx, in, in.readableBytes());
        } catch (Throwable cause) {
            handleUnwrapThrowable(ctx, cause);
        }
    }

    private void handleUnwrapThrowable(ChannelHandlerContext ctx, Throwable cause) {
        try {
            // We should attempt to notify the handshake failure before writing any pending data. If we are in unwrap
            // and failed during the handshake process, and we attempt to wrap, then promises will fail, and if
            // listeners immediately close the Channel then we may end up firing the handshake event after the Channel
            // has been closed.
            if (handshakePromise.tryFailure(cause)) {
                ctx.fireUserEventTriggered(new SslHandshakeCompletionEvent(cause));
            }

            // Let's check if the handler was removed in the meantime and so pendingUnencryptedWrites is null.
            if (pendingUnencryptedWrites != null) {
                // We need to flush one time as there may be an alert that we should send to the remote peer because
                // of the SSLException reported here.
                wrapAndFlush(ctx);
            }
        } catch (SSLException ex) {
            logger.debug("SSLException during trying to call SSLEngine.wrap(...)" +
                    " because of an previous SSLException, ignoring...", ex);
        } finally {
            // ensure we always flush and close the channel.
            setHandshakeFailure(ctx, cause, true, false, true);
        }
        PlatformDependent.throwException(cause);
    }

    @Override
    protected void decode(ChannelHandlerContext ctx, ByteBuf in, List out) throws SSLException {
        if (isStateSet(STATE_PROCESS_TASK)) {
            return;
        }
        if (jdkCompatibilityMode) {
            decodeJdkCompatible(ctx, in);
        } else {
            decodeNonJdkCompatible(ctx, in);
        }
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        channelReadComplete0(ctx);
    }

    private void channelReadComplete0(ChannelHandlerContext ctx) {
        // Discard bytes of the cumulation buffer if needed.
        discardSomeReadBytes();

        flushIfNeeded(ctx);
        readIfNeeded(ctx);

        clearState(STATE_FIRE_CHANNEL_READ);
        ctx.fireChannelReadComplete();
    }

    private void readIfNeeded(ChannelHandlerContext ctx) {
        // If handshake is not finished yet, we need more data.
        if (!ctx.channel().config().isAutoRead() &&
                (!isStateSet(STATE_FIRE_CHANNEL_READ) || !handshakePromise.isDone())) {
            // No auto-read used and no message passed through the ChannelPipeline or the handshake was not complete
            // yet, which means we need to trigger the read to ensure we not encounter any stalls.
            ctx.read();
        }
    }

    private void flushIfNeeded(ChannelHandlerContext ctx) {
        if (isStateSet(STATE_NEEDS_FLUSH)) {
            forceFlush(ctx);
        }
    }

    /**
     * Calls {@link SSLEngine#unwrap(ByteBuffer, ByteBuffer)} with an empty buffer to handle handshakes, etc.
     */
    private int unwrapNonAppData(ChannelHandlerContext ctx) throws SSLException {
        return unwrap(ctx, Unpooled.EMPTY_BUFFER, 0);
    }

    /**
     * Unwraps inbound SSL records.
     */
    private int unwrap(ChannelHandlerContext ctx, ByteBuf packet, int length) throws SSLException {
        final int originalLength = length;
        boolean wrapLater = false;
        boolean notifyClosure = false;
        boolean executedRead = false;
        ByteBuf decodeOut = allocate(ctx, length);
        try {
            // Only continue to loop if the handler was not removed in the meantime.
            // See https://github.com/netty/netty/issues/5860
            do {
                final SSLEngineResult result = engineType.unwrap(this, packet, length, decodeOut);
                final Status status = result.getStatus();
                final HandshakeStatus handshakeStatus = result.getHandshakeStatus();
                final int produced = result.bytesProduced();
                final int consumed = result.bytesConsumed();

                // Skip bytes now in case unwrap is called in a re-entry scenario. For example LocalChannel.read()
                // may entry this method in a re-entry fashion and if the peer is writing into a shared buffer we may
                // unwrap the same data multiple times.
                packet.skipBytes(consumed);
                length -= consumed;

                // The expected sequence of events is:
                // 1. Notify of handshake success
                // 2. fireChannelRead for unwrapped data
                if (handshakeStatus == HandshakeStatus.FINISHED || handshakeStatus == HandshakeStatus.NOT_HANDSHAKING) {
                    wrapLater |= (decodeOut.isReadable() ?
                            setHandshakeSuccessUnwrapMarkReentry() : setHandshakeSuccess()) ||
                            handshakeStatus == HandshakeStatus.FINISHED;
                }

                // Dispatch decoded data after we have notified of handshake success. If this method has been invoked
                // in a re-entry fashion we execute a task on the executor queue to process after the stack unwinds
                // to preserve order of events.
                if (decodeOut.isReadable()) {
                    setState(STATE_FIRE_CHANNEL_READ);
                    if (isStateSet(STATE_UNWRAP_REENTRY)) {
                        executedRead = true;
                        executeChannelRead(ctx, decodeOut);
                    } else {
                        ctx.fireChannelRead(decodeOut);
                    }
                    decodeOut = null;
                }

                if (status == Status.CLOSED) {
                    notifyClosure = true; // notify about the CLOSED state of the SSLEngine. See #137
                } else if (status == Status.BUFFER_OVERFLOW) {
                    if (decodeOut != null) {
                        decodeOut.release();
                    }
                    final int applicationBufferSize = engine.getSession().getApplicationBufferSize();
                    // Allocate a new buffer which can hold all the rest data and loop again.
                    // It may happen that applicationBufferSize < produced while there is still more to unwrap, in this
                    // case we will just allocate a new buffer with the capacity of applicationBufferSize and call
                    // unwrap again.
                    decodeOut = allocate(ctx, engineType.calculatePendingData(this, applicationBufferSize < produced ?
                            applicationBufferSize : applicationBufferSize - produced));
                    continue;
                }

                if (handshakeStatus == HandshakeStatus.NEED_TASK) {
                    boolean pending = runDelegatedTasks(true);
                    if (!pending) {
                        // We scheduled a task on the delegatingTaskExecutor, so stop processing as we will
                        // resume once the task completes.
                        //
                        // We break out of the loop only and do NOT return here as we still may need to notify
                        // about the closure of the SSLEngine.
                        wrapLater = false;
                        break;
                    }
                } else if (handshakeStatus == HandshakeStatus.NEED_WRAP) {
                    // If the wrap operation transitions the status to NOT_HANDSHAKING and there is no more data to
                    // unwrap then the next call to unwrap will not produce any data. We can avoid the potentially
                    // costly unwrap operation and break out of the loop.
                    if (wrapNonAppData(ctx, true) && length == 0) {
                        break;
                    }
                }

                if (status == Status.BUFFER_UNDERFLOW ||
                        // If we processed NEED_TASK we should try again even we did not consume or produce anything.
                        handshakeStatus != HandshakeStatus.NEED_TASK && (consumed == 0 && produced == 0 ||
                                (length == 0 && handshakeStatus == HandshakeStatus.NOT_HANDSHAKING))) {
                    if (handshakeStatus == HandshakeStatus.NEED_UNWRAP) {
                        // The underlying engine is starving so we need to feed it with more data.
                        // See https://github.com/netty/netty/pull/5039
                        readIfNeeded(ctx);
                    }

                    break;
                } else if (decodeOut == null) {
                    decodeOut = allocate(ctx, length);
                }
            } while (!ctx.isRemoved());

            if (isStateSet(STATE_FLUSHED_BEFORE_HANDSHAKE) && handshakePromise.isDone()) {
                // We need to call wrap(...) in case there was a flush done before the handshake completed to ensure
                // we do not stale.
                //
                // See https://github.com/netty/netty/pull/2437
                clearState(STATE_FLUSHED_BEFORE_HANDSHAKE);
                wrapLater = true;
            }

            if (wrapLater) {
                wrap(ctx, true);
            }
        } finally {
            if (decodeOut != null) {
                decodeOut.release();
            }

            if (notifyClosure) {
                if (executedRead) {
                    executeNotifyClosePromise(ctx);
                } else {
                    notifyClosePromise(null);
                }
            }
        }
        return originalLength - length;
    }

    private boolean setHandshakeSuccessUnwrapMarkReentry() {
        // setHandshakeSuccess calls out to external methods which may trigger re-entry. We need to preserve ordering of
        // fireChannelRead for decodeOut relative to re-entry data.
        final boolean setReentryState = !isStateSet(STATE_UNWRAP_REENTRY);
        if (setReentryState) {
            setState(STATE_UNWRAP_REENTRY);
        }
        try {
            return setHandshakeSuccess();
        } finally {
            // It is unlikely this specific method will be re-entry because handshake completion is infrequent, but just
            // in case we only clear the state if we set it in the first place.
            if (setReentryState) {
                clearState(STATE_UNWRAP_REENTRY);
            }
        }
    }

    private void executeNotifyClosePromise(final ChannelHandlerContext ctx) {
        try {
            ctx.executor().execute(new Runnable() {
                @Override
                public void run() {
                    notifyClosePromise(null);
                }
            });
        } catch (RejectedExecutionException e) {
            notifyClosePromise(e);
        }
    }

    private void executeChannelRead(final ChannelHandlerContext ctx, final ByteBuf decodedOut) {
        try {
            ctx.executor().execute(new Runnable() {
                @Override
                public void run() {
                    ctx.fireChannelRead(decodedOut);
                }
            });
        } catch (RejectedExecutionException e) {
            decodedOut.release();
            throw e;
        }
    }

    private static ByteBuffer toByteBuffer(ByteBuf out, int index, int len) {
        return out.nioBufferCount() == 1 ? out.internalNioBuffer(index, len) :
                out.nioBuffer(index, len);
    }

    private static boolean inEventLoop(Executor executor) {
        return executor instanceof EventExecutor && ((EventExecutor) executor).inEventLoop();
    }

    /**
     * Will either run the delegated task directly calling {@link Runnable#run()} and return {@code true} or will
     * offload the delegated task using {@link Executor#execute(Runnable)} and return {@code false}.
     *
     * If the task is offloaded it will take care to resume its work on the {@link EventExecutor} once there are no
     * more tasks to process.
     */
    private boolean runDelegatedTasks(boolean inUnwrap) {
        if (delegatedTaskExecutor == ImmediateExecutor.INSTANCE || inEventLoop(delegatedTaskExecutor)) {
            // We should run the task directly in the EventExecutor thread and not offload at all. As we are on the
            // EventLoop we can just run all tasks at once.
            for (;;) {
                Runnable task = engine.getDelegatedTask();
                if (task == null) {
                    return true;
                }
                setState(STATE_PROCESS_TASK);
                if (task instanceof AsyncRunnable) {
                    // Let's set the task to processing task before we try to execute it.
                    boolean pending = false;
                    try {
                        AsyncRunnable asyncTask = (AsyncRunnable) task;
                        AsyncTaskCompletionHandler completionHandler = new AsyncTaskCompletionHandler(inUnwrap);
                        asyncTask.run(completionHandler);
                        pending = completionHandler.resumeLater();
                        if (pending) {
                            return false;
                        }
                    } finally {
                        if (!pending) {
                            // The task has completed, lets clear the state. If it is not completed we will clear the
                            // state once it is.
                            clearState(STATE_PROCESS_TASK);
                        }
                    }
                } else {
                    try {
                        task.run();
                    } finally {
                        clearState(STATE_PROCESS_TASK);
                    }
                }
            }
        } else {
            executeDelegatedTask(inUnwrap);
            return false;
        }
    }

    private SslTasksRunner getTaskRunner(boolean inUnwrap) {
        return inUnwrap ? sslTaskRunnerForUnwrap : sslTaskRunner;
    }

    private void executeDelegatedTask(boolean inUnwrap) {
        executeDelegatedTask(getTaskRunner(inUnwrap));
    }

    private void executeDelegatedTask(SslTasksRunner task) {
        setState(STATE_PROCESS_TASK);
        try {
            delegatedTaskExecutor.execute(task);
        } catch (RejectedExecutionException e) {
            clearState(STATE_PROCESS_TASK);
            throw e;
        }
    }

    private final class AsyncTaskCompletionHandler implements Runnable {
        private final boolean inUnwrap;
        boolean didRun;
        boolean resumeLater;

        AsyncTaskCompletionHandler(boolean inUnwrap) {
            this.inUnwrap = inUnwrap;
        }

        @Override
        public void run() {
            didRun = true;
            if (resumeLater) {
                getTaskRunner(inUnwrap).runComplete();
            }
        }

        boolean resumeLater() {
            if (!didRun) {
                resumeLater = true;
                return true;
            }
            return false;
        }
    }

    /**
     * {@link Runnable} that will be scheduled on the {@code delegatedTaskExecutor} and will take care
     * of resume work on the {@link EventExecutor} once the task was executed.
     */
    private final class SslTasksRunner implements Runnable {
        private final boolean inUnwrap;
        private final Runnable runCompleteTask = new Runnable() {
            @Override
            public void run() {
                runComplete();
            }
        };

        SslTasksRunner(boolean inUnwrap) {
            this.inUnwrap = inUnwrap;
        }

        // Handle errors which happened during task processing.
        private void taskError(Throwable e) {
            if (inUnwrap) {
                // As the error happened while the task was scheduled as part of unwrap(...) we also need to ensure
                // we fire it through the pipeline as inbound error to be consistent with what we do in decode(...).
                //
                // This will also ensure we fail the handshake future and flush all produced data.
                try {
                    handleUnwrapThrowable(ctx, e);
                } catch (Throwable cause) {
                    safeExceptionCaught(cause);
                }
            } else {
                setHandshakeFailure(ctx, e);
                forceFlush(ctx);
            }
        }

        // Try to call exceptionCaught(...)
        private void safeExceptionCaught(Throwable cause) {
            try {
                exceptionCaught(ctx, wrapIfNeeded(cause));
            } catch (Throwable error) {
                ctx.fireExceptionCaught(error);
            }
        }

        private Throwable wrapIfNeeded(Throwable cause) {
            if (!inUnwrap) {
                // If we are not in unwrap(...) we can just rethrow without wrapping at all.
                return cause;
            }
            // As the exception would have been triggered by an inbound operation we will need to wrap it in a
            // DecoderException to mimic what a decoder would do when decode(...) throws.
            return cause instanceof DecoderException ? cause : new DecoderException(cause);
        }

        private void tryDecodeAgain() {
            try {
                channelRead(ctx, Unpooled.EMPTY_BUFFER);
            } catch (Throwable cause) {
                safeExceptionCaught(cause);
            } finally {
                // As we called channelRead(...) we also need to call channelReadComplete(...) which
                // will ensure we either call ctx.fireChannelReadComplete() or will trigger a ctx.read() if
                // more data is needed.
                channelReadComplete0(ctx);
            }
        }

        /**
         * Executed after the wrapped {@code task} was executed via {@code delegatedTaskExecutor} to resume work
         * on the {@link EventExecutor}.
         */
        private void resumeOnEventExecutor() {
            assert ctx.executor().inEventLoop();
            clearState(STATE_PROCESS_TASK);
            try {
                HandshakeStatus status = engine.getHandshakeStatus();
                switch (status) {
                    // There is another task that needs to be executed and offloaded to the delegatingTaskExecutor as
                    // a result of this. Let's reschedule....
                    case NEED_TASK:
                        executeDelegatedTask(this);

                        break;

                    // The handshake finished, lets notify about the completion of it and resume processing.
                    case FINISHED:
                    // Not handshaking anymore, lets notify about the completion if not done yet and resume processing.
                    case NOT_HANDSHAKING:
                        setHandshakeSuccess(); // NOT_HANDSHAKING -> workaround for android skipping FINISHED state.
                        try {
                            // Lets call wrap to ensure we produce the alert if there is any pending and also to
                            // ensure we flush any queued data..
                            wrap(ctx, inUnwrap);
                        } catch (Throwable e) {
                            taskError(e);
                            return;
                        }
                        if (inUnwrap) {
                            // If we were in the unwrap call when the task was processed we should also try to unwrap
                            // non app data first as there may not anything left in the inbound buffer to process.
                            unwrapNonAppData(ctx);
                        }

                        // Flush now as we may have written some data as part of the wrap call.
                        forceFlush(ctx);

                        tryDecodeAgain();
                        break;

                    // We need more data so lets try to unwrap first and then call decode again which will feed us
                    // with buffered data (if there is any).
                    case NEED_UNWRAP:
                        try {
                            unwrapNonAppData(ctx);
                        } catch (SSLException e) {
                            handleUnwrapThrowable(ctx, e);
                            return;
                        }
                        tryDecodeAgain();
                        break;

                    // To make progress we need to call SSLEngine.wrap(...) which may produce more output data
                    // that will be written to the Channel.
                    case NEED_WRAP:
                        try {
                            if (!wrapNonAppData(ctx, false) && inUnwrap) {
                                // The handshake finished in wrapNonAppData(...), we need to try call
                                // unwrapNonAppData(...) as we may have some alert that we should read.
                                //
                                // This mimics what we would do when we are calling this method while in unwrap(...).
                                unwrapNonAppData(ctx);
                            }

                            // Flush now as we may have written some data as part of the wrap call.
                            forceFlush(ctx);
                        } catch (Throwable e) {
                            taskError(e);
                            return;
                        }

                        // Now try to feed in more data that we have buffered.
                        tryDecodeAgain();
                        break;

                    default:
                        // Should never reach here as we handle all cases.
                        throw new AssertionError();
                }
            } catch (Throwable cause) {
                safeExceptionCaught(cause);
            }
        }

        void runComplete() {
            EventExecutor executor = ctx.executor();
            // Jump back on the EventExecutor. We do this even if we are already on the EventLoop to guard against
            // reentrancy issues. Failing to do so could lead to the situation of tryDecode(...) be called and so
            // channelRead(...) while still in the decode loop. In this case channelRead(...) might release the input
            // buffer if its empty which would then result in an IllegalReferenceCountException when we try to continue
            // decoding.
            //
            // See https://github.com/netty/netty-tcnative/issues/680
            executor.execute(new Runnable() {
                @Override
                public void run() {
                    resumeOnEventExecutor();
                }
            });
        }

        @Override
        public void run() {
            try {
                Runnable task = engine.getDelegatedTask();
                if (task == null) {
                    // The task was processed in the meantime. Let's just return.
                    return;
                }
                if (task instanceof AsyncRunnable) {
                    AsyncRunnable asyncTask = (AsyncRunnable) task;
                    asyncTask.run(runCompleteTask);
                } else {
                    task.run();
                    runComplete();
                }
            } catch (final Throwable cause) {
                handleException(cause);
            }
        }

        private void handleException(final Throwable cause) {
            EventExecutor executor = ctx.executor();
            if (executor.inEventLoop()) {
                clearState(STATE_PROCESS_TASK);
                safeExceptionCaught(cause);
            } else {
                try {
                    executor.execute(new Runnable() {
                        @Override
                        public void run() {
                            clearState(STATE_PROCESS_TASK);
                            safeExceptionCaught(cause);
                        }
                    });
                } catch (RejectedExecutionException ignore) {
                    clearState(STATE_PROCESS_TASK);
                    // the context itself will handle the rejected exception when try to schedule the operation so
                    // ignore the RejectedExecutionException
                    ctx.fireExceptionCaught(cause);
                }
            }
        }
    }

    /**
     * Notify all the handshake futures about the successfully handshake
     * @return {@code true} if {@link #handshakePromise} was set successfully and a {@link SslHandshakeCompletionEvent}
     * was fired. {@code false} otherwise.
     */
    private boolean setHandshakeSuccess() {
        // Our control flow may invoke this method multiple times for a single FINISHED event. For example
        // wrapNonAppData may drain pendingUnencryptedWrites in wrap which transitions to handshake from FINISHED to
        // NOT_HANDSHAKING which invokes setHandshakeSuccess, and then wrapNonAppData also directly invokes this method.
        final boolean notified;
        if (notified = !handshakePromise.isDone() && handshakePromise.trySuccess(ctx.channel())) {
            if (logger.isDebugEnabled()) {
                SSLSession session = engine.getSession();
                logger.debug(
                        "{} HANDSHAKEN: protocol:{} cipher suite:{}",
                        ctx.channel(),
                        session.getProtocol(),
                        session.getCipherSuite());
            }
            ctx.fireUserEventTriggered(SslHandshakeCompletionEvent.SUCCESS);
        }
        if (isStateSet(STATE_READ_DURING_HANDSHAKE)) {
            clearState(STATE_READ_DURING_HANDSHAKE);
            if (!ctx.channel().config().isAutoRead()) {
                ctx.read();
            }
        }
        return notified;
    }

    /**
     * Notify all the handshake futures about the failure during the handshake.
     */
    private void setHandshakeFailure(ChannelHandlerContext ctx, Throwable cause) {
        setHandshakeFailure(ctx, cause, true, true, false);
    }

    /**
     * Notify all the handshake futures about the failure during the handshake.
     */
    private void setHandshakeFailure(ChannelHandlerContext ctx, Throwable cause, boolean closeInbound,
                                     boolean notify, boolean alwaysFlushAndClose) {
        try {
            // Release all resources such as internal buffers that SSLEngine is managing.
            setState(STATE_OUTBOUND_CLOSED);
            engine.closeOutbound();

            if (closeInbound) {
                try {
                    engine.closeInbound();
                } catch (SSLException e) {
                    if (logger.isDebugEnabled()) {
                        // only log in debug mode as it most likely harmless and latest chrome still trigger
                        // this all the time.
                        //
                        // See https://github.com/netty/netty/issues/1340
                        String msg = e.getMessage();
                        if (msg == null || !(msg.contains("possible truncation attack") ||
                                msg.contains("closing inbound before receiving peer's close_notify"))) {
                            logger.debug("{} SSLEngine.closeInbound() raised an exception.", ctx.channel(), e);
                        }
                    }
                }
            }
            if (handshakePromise.tryFailure(cause) || alwaysFlushAndClose) {
                SslUtils.handleHandshakeFailure(ctx, cause, notify);
            }
        } finally {
            // Ensure we remove and fail all pending writes in all cases and so release memory quickly.
            releaseAndFailAll(ctx, cause);
        }
    }

    private void setHandshakeFailureTransportFailure(ChannelHandlerContext ctx, Throwable cause) {
        // If TLS control frames fail to write we are in an unknown state and may become out of
        // sync with our peer. We give up and close the channel. This will also take care of
        // cleaning up any outstanding state (e.g. handshake promise, queued unencrypted data).
        try {
            SSLException transportFailure = new SSLException("failure when writing TLS control frames", cause);
            releaseAndFailAll(ctx, transportFailure);
            if (handshakePromise.tryFailure(transportFailure)) {
                ctx.fireUserEventTriggered(new SslHandshakeCompletionEvent(transportFailure));
            }
        } finally {
            ctx.close();
        }
    }

    private void releaseAndFailAll(ChannelHandlerContext ctx, Throwable cause) {
        if (pendingUnencryptedWrites != null) {
            pendingUnencryptedWrites.releaseAndFailAll(ctx, cause);
        }
    }

    private void notifyClosePromise(Throwable cause) {
        if (cause == null) {
            if (sslClosePromise.trySuccess(ctx.channel())) {
                ctx.fireUserEventTriggered(SslCloseCompletionEvent.SUCCESS);
            }
        } else {
            if (sslClosePromise.tryFailure(cause)) {
                ctx.fireUserEventTriggered(new SslCloseCompletionEvent(cause));
            }
        }
    }

    private void closeOutboundAndChannel(
            final ChannelHandlerContext ctx, final ChannelPromise promise, boolean disconnect) throws Exception {
        setState(STATE_OUTBOUND_CLOSED);
        engine.closeOutbound();

        if (!ctx.channel().isActive()) {
            if (disconnect) {
                ctx.disconnect(promise);
            } else {
                ctx.close(promise);
            }
            return;
        }

        ChannelPromise closeNotifyPromise = ctx.newPromise();
        try {
            flush(ctx, closeNotifyPromise);
        } finally {
            if (!isStateSet(STATE_CLOSE_NOTIFY)) {
                setState(STATE_CLOSE_NOTIFY);
                // It's important that we do not pass the original ChannelPromise to safeClose(...) as when flush(....)
                // throws an Exception it will be propagated to the AbstractChannelHandlerContext which will try
                // to fail the promise because of this. This will then fail as it was already completed by
                // safeClose(...). We create a new ChannelPromise and try to notify the original ChannelPromise
                // once it is complete. If we fail to do so we just ignore it as in this case it was failed already
                // because of a propagated Exception.
                //
                // See https://github.com/netty/netty/issues/5931
                safeClose(ctx, closeNotifyPromise, PromiseNotifier.cascade(false, ctx.newPromise(), promise));
            } else {
                /// We already handling the close_notify so just attach the promise to the sslClosePromise.
                sslClosePromise.addListener(new FutureListener() {
                    @Override
                    public void operationComplete(Future future) {
                        promise.setSuccess();
                    }
                });
            }
        }
    }

    private void flush(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception {
        if (pendingUnencryptedWrites != null) {
            pendingUnencryptedWrites.add(Unpooled.EMPTY_BUFFER, promise);
        } else {
            promise.setFailure(newPendingWritesNullException());
        }
        flush(ctx);
    }

    @Override
    public void handlerAdded(final ChannelHandlerContext ctx) throws Exception {
        this.ctx = ctx;
        Channel channel = ctx.channel();
        pendingUnencryptedWrites = new SslHandlerCoalescingBufferQueue(channel, 16);

        setOpensslEngineSocketFd(channel);
        boolean fastOpen = Boolean.TRUE.equals(channel.config().getOption(ChannelOption.TCP_FASTOPEN_CONNECT));
        boolean active = channel.isActive();
        if (active || fastOpen) {
            // Explicitly flush the handshake only if the channel is already active.
            // With TCP Fast Open, we write to the outbound buffer before the TCP connect is established.
            // The buffer will then be flushed as part of establishing the connection, saving us a round-trip.
            startHandshakeProcessing(active);
            // If we weren't able to include client_hello in the TCP SYN (e.g. no token, disabled at the OS) we have to
            // flush pending data in the outbound buffer later in channelActive().
            final ChannelOutboundBuffer outboundBuffer;
            if (fastOpen && ((outboundBuffer = channel.unsafe().outboundBuffer()) == null ||
                    outboundBuffer.totalPendingWriteBytes() > 0)) {
                setState(STATE_NEEDS_FLUSH);
            }
        }
    }

    private void startHandshakeProcessing(boolean flushAtEnd) {
        if (!isStateSet(STATE_HANDSHAKE_STARTED)) {
            setState(STATE_HANDSHAKE_STARTED);
            if (engine.getUseClientMode()) {
                // Begin the initial handshake.
                // channelActive() event has been fired already, which means this.channelActive() will
                // not be invoked. We have to initialize here instead.
                handshake(flushAtEnd);
            }
            applyHandshakeTimeout();
        } else if (isStateSet(STATE_NEEDS_FLUSH)) {
            forceFlush(ctx);
        }
    }

    /**
     * Performs TLS renegotiation.
     */
    public Future renegotiate() {
        ChannelHandlerContext ctx = this.ctx;
        if (ctx == null) {
            throw new IllegalStateException();
        }

        return renegotiate(ctx.executor().newPromise());
    }

    /**
     * Performs TLS renegotiation.
     */
    public Future renegotiate(final Promise promise) {
        ObjectUtil.checkNotNull(promise, "promise");

        ChannelHandlerContext ctx = this.ctx;
        if (ctx == null) {
            throw new IllegalStateException();
        }

        EventExecutor executor = ctx.executor();
        if (!executor.inEventLoop()) {
            executor.execute(new Runnable() {
                @Override
                public void run() {
                    renegotiateOnEventLoop(promise);
                }
            });
            return promise;
        }

        renegotiateOnEventLoop(promise);
        return promise;
    }

    private void renegotiateOnEventLoop(final Promise newHandshakePromise) {
        final Promise oldHandshakePromise = handshakePromise;
        if (!oldHandshakePromise.isDone()) {
            // There's no need to handshake because handshake is in progress already.
            // Merge the new promise into the old one.
            PromiseNotifier.cascade(oldHandshakePromise, newHandshakePromise);
        } else {
            handshakePromise = newHandshakePromise;
            handshake(true);
            applyHandshakeTimeout();
        }
    }

    /**
     * Performs TLS (re)negotiation.
     * @param flushAtEnd Set to {@code true} if the outbound buffer should be flushed (written to the network) at the
     *                  end. Set to {@code false} if the handshake will be flushed later, e.g. as part of TCP Fast Open
     *                  connect.
     */
    private void handshake(boolean flushAtEnd) {
        if (engine.getHandshakeStatus() != HandshakeStatus.NOT_HANDSHAKING) {
            // Not all SSLEngine implementations support calling beginHandshake multiple times while a handshake
            // is in progress. See https://github.com/netty/netty/issues/4718.
            return;
        }
        if (handshakePromise.isDone()) {
            // If the handshake is done already lets just return directly as there is no need to trigger it again.
            // This can happen if the handshake(...) was triggered before we called channelActive(...) by a
            // flush() that was triggered by a ChannelFutureListener that was added to the ChannelFuture returned
            // from the connect(...) method. In this case we will see the flush() happen before we had a chance to
            // call fireChannelActive() on the pipeline.
            return;
        }

        // Begin handshake.
        final ChannelHandlerContext ctx = this.ctx;
        try {
            engine.beginHandshake();
            wrapNonAppData(ctx, false);
        } catch (Throwable e) {
            setHandshakeFailure(ctx, e);
        } finally {
            if (flushAtEnd) {
                forceFlush(ctx);
            }
        }
    }

    private void applyHandshakeTimeout() {
        final Promise localHandshakePromise = this.handshakePromise;

        // Set timeout if necessary.
        final long handshakeTimeoutMillis = this.handshakeTimeoutMillis;
        if (handshakeTimeoutMillis <= 0 || localHandshakePromise.isDone()) {
            return;
        }

        final Future timeoutFuture = ctx.executor().schedule(new Runnable() {
            @Override
            public void run() {
                if (localHandshakePromise.isDone()) {
                    return;
                }
                SSLException exception =
                        new SslHandshakeTimeoutException("handshake timed out after " + handshakeTimeoutMillis + "ms");
                try {
                    if (localHandshakePromise.tryFailure(exception)) {
                        SslUtils.handleHandshakeFailure(ctx, exception, true);
                    }
                } finally {
                    releaseAndFailAll(ctx, exception);
                }
            }
        }, handshakeTimeoutMillis, TimeUnit.MILLISECONDS);

        // Cancel the handshake timeout when handshake is finished.
        localHandshakePromise.addListener(new FutureListener() {
            @Override
            public void operationComplete(Future f) throws Exception {
                timeoutFuture.cancel(false);
            }
        });
    }

    private void forceFlush(ChannelHandlerContext ctx) {
        clearState(STATE_NEEDS_FLUSH);
        ctx.flush();
    }

     private void setOpensslEngineSocketFd(Channel c) {
         if (c instanceof UnixChannel && engine instanceof ReferenceCountedOpenSslEngine) {
             ((ReferenceCountedOpenSslEngine) engine).bioSetFd(((UnixChannel) c).fd().intValue());
         }
     }

    /**
     * Issues an initial TLS handshake once connected when used in client-mode
     */
    @Override
    public void channelActive(final ChannelHandlerContext ctx) throws Exception {
        setOpensslEngineSocketFd(ctx.channel());
        if (!startTls) {
            startHandshakeProcessing(true);
        }
        ctx.fireChannelActive();
    }

    private void safeClose(
            final ChannelHandlerContext ctx, final ChannelFuture flushFuture,
            final ChannelPromise promise) {
        if (!ctx.channel().isActive()) {
            ctx.close(promise);
            return;
        }

        final Future timeoutFuture;
        if (!flushFuture.isDone()) {
            long closeNotifyTimeout = closeNotifyFlushTimeoutMillis;
            if (closeNotifyTimeout > 0) {
                // Force-close the connection if close_notify is not fully sent in time.
                timeoutFuture = ctx.executor().schedule(new Runnable() {
                    @Override
                    public void run() {
                        // May be done in the meantime as cancel(...) is only best effort.
                        if (!flushFuture.isDone()) {
                            logger.warn("{} Last write attempt timed out; force-closing the connection.",
                                    ctx.channel());
                            addCloseListener(ctx.close(ctx.newPromise()), promise);
                        }
                    }
                }, closeNotifyTimeout, TimeUnit.MILLISECONDS);
            } else {
                timeoutFuture = null;
            }
        } else {
            timeoutFuture = null;
        }

        // Close the connection if close_notify is sent in time.
        flushFuture.addListener(new ChannelFutureListener() {
            @Override
            public void operationComplete(ChannelFuture f) {
                if (timeoutFuture != null) {
                    timeoutFuture.cancel(false);
                }
                final long closeNotifyReadTimeout = closeNotifyReadTimeoutMillis;
                if (closeNotifyReadTimeout <= 0) {
                    // Trigger the close in all cases to make sure the promise is notified
                    // See https://github.com/netty/netty/issues/2358
                    addCloseListener(ctx.close(ctx.newPromise()), promise);
                } else {
                    final Future closeNotifyReadTimeoutFuture;

                    if (!sslClosePromise.isDone()) {
                        closeNotifyReadTimeoutFuture = ctx.executor().schedule(new Runnable() {
                            @Override
                            public void run() {
                                if (!sslClosePromise.isDone()) {
                                    logger.debug(
                                            "{} did not receive close_notify in {}ms; force-closing the connection.",
                                            ctx.channel(), closeNotifyReadTimeout);

                                    // Do the close now...
                                    addCloseListener(ctx.close(ctx.newPromise()), promise);
                                }
                            }
                        }, closeNotifyReadTimeout, TimeUnit.MILLISECONDS);
                    } else {
                        closeNotifyReadTimeoutFuture = null;
                    }

                    // Do the close once the we received the close_notify.
                    sslClosePromise.addListener(new FutureListener() {
                        @Override
                        public void operationComplete(Future future) throws Exception {
                            if (closeNotifyReadTimeoutFuture != null) {
                                closeNotifyReadTimeoutFuture.cancel(false);
                            }
                            addCloseListener(ctx.close(ctx.newPromise()), promise);
                        }
                    });
                }
            }
        });
    }

    private static void addCloseListener(ChannelFuture future, ChannelPromise promise) {
        // We notify the promise in the ChannelPromiseNotifier as there is a "race" where the close(...) call
        // by the timeoutFuture and the close call in the flushFuture listener will be called. Because of
        // this we need to use trySuccess() and tryFailure(...) as otherwise we can cause an
        // IllegalStateException.
        // Also we not want to log if the notification happens as this is expected in some cases.
        // See https://github.com/netty/netty/issues/5598
        PromiseNotifier.cascade(false, future, promise);
    }

    /**
     * Always prefer a direct buffer when it's pooled, so that we reduce the number of memory copies
     * in {@link OpenSslEngine}.
     */
    private ByteBuf allocate(ChannelHandlerContext ctx, int capacity) {
        ByteBufAllocator alloc = ctx.alloc();
        if (engineType.wantsDirectBuffer) {
            return alloc.directBuffer(capacity);
        } else {
            return alloc.buffer(capacity);
        }
    }

    /**
     * Allocates an outbound network buffer for {@link SSLEngine#wrap(ByteBuffer, ByteBuffer)} which can encrypt
     * the specified amount of pending bytes.
     */
    private ByteBuf allocateOutNetBuf(ChannelHandlerContext ctx, int pendingBytes, int numComponents) {
        return engineType.allocateWrapBuffer(this, ctx.alloc(), pendingBytes, numComponents);
    }

    private boolean isStateSet(int bit) {
        return (state & bit) == bit;
    }

    private void setState(int bit) {
        state |= bit;
    }

    private void clearState(int bit) {
        state &= ~bit;
    }

    /**
     * Each call to SSL_write will introduce about ~100 bytes of overhead. This coalescing queue attempts to increase
     * goodput by aggregating the plaintext in chunks of {@link #wrapDataSize}. If many small chunks are written
     * this can increase goodput, decrease the amount of calls to SSL_write, and decrease overall encryption operations.
     */
    private final class SslHandlerCoalescingBufferQueue extends AbstractCoalescingBufferQueue {

        SslHandlerCoalescingBufferQueue(Channel channel, int initSize) {
            super(channel, initSize);
        }

        @Override
        protected ByteBuf compose(ByteBufAllocator alloc, ByteBuf cumulation, ByteBuf next) {
            final int wrapDataSize = SslHandler.this.wrapDataSize;
            if (cumulation instanceof CompositeByteBuf) {
                CompositeByteBuf composite = (CompositeByteBuf) cumulation;
                int numComponents = composite.numComponents();
                if (numComponents == 0 ||
                        !attemptCopyToCumulation(composite.internalComponent(numComponents - 1), next, wrapDataSize)) {
                    composite.addComponent(true, next);
                }
                return composite;
            }
            return attemptCopyToCumulation(cumulation, next, wrapDataSize) ? cumulation :
                    copyAndCompose(alloc, cumulation, next);
        }

        @Override
        protected ByteBuf composeFirst(ByteBufAllocator allocator, ByteBuf first) {
            if (first instanceof CompositeByteBuf) {
                CompositeByteBuf composite = (CompositeByteBuf) first;
                if (engineType.wantsDirectBuffer) {
                    first = allocator.directBuffer(composite.readableBytes());
                } else {
                    first = allocator.heapBuffer(composite.readableBytes());
                }
                try {
                    first.writeBytes(composite);
                } catch (Throwable cause) {
                    first.release();
                    PlatformDependent.throwException(cause);
                }
                composite.release();
            }
            return first;
        }

        @Override
        protected ByteBuf removeEmptyValue() {
            return null;
        }
    }

    private static boolean attemptCopyToCumulation(ByteBuf cumulation, ByteBuf next, int wrapDataSize) {
        final int inReadableBytes = next.readableBytes();
        final int cumulationCapacity = cumulation.capacity();
        if (wrapDataSize - cumulation.readableBytes() >= inReadableBytes &&
                // Avoid using the same buffer if next's data would make cumulation exceed the wrapDataSize.
                // Only copy if there is enough space available and the capacity is large enough, and attempt to
                // resize if the capacity is small.
                (cumulation.isWritable(inReadableBytes) && cumulationCapacity >= wrapDataSize ||
                        cumulationCapacity < wrapDataSize &&
                                ensureWritableSuccess(cumulation.ensureWritable(inReadableBytes, false)))) {
            cumulation.writeBytes(next);
            next.release();
            return true;
        }
        return false;
    }

    private final class LazyChannelPromise extends DefaultPromise {

        @Override
        protected EventExecutor executor() {
            if (ctx == null) {
                throw new IllegalStateException();
            }
            return ctx.executor();
        }

        @Override
        protected void checkDeadLock() {
            if (ctx == null) {
                // If ctx is null the handlerAdded(...) callback was not called, in this case the checkDeadLock()
                // method was called from another Thread then the one that is used by ctx.executor(). We need to
                // guard against this as a user can see a race if handshakeFuture().sync() is called but the
                // handlerAdded(..) method was not yet as it is called from the EventExecutor of the
                // ChannelHandlerContext. If we not guard against this super.checkDeadLock() would cause an
                // IllegalStateException when trying to call executor().
                return;
            }
            super.checkDeadLock();
        }
    }
}
    

    

    

            

    

            



    
    






    
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