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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:
*
* http://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.
*/
/*
* Copyright 2012 Twitter, Inc.
*
* Licensed 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
*
* http://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.codec.spdy;
import java.net.SocketAddress;
import java.nio.channels.ClosedChannelException;
import java.util.concurrent.atomic.AtomicInteger;
import io.netty.channel.Channel;
import io.netty.channel.ChannelDownstreamHandler;
import io.netty.channel.ChannelEvent;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelStateEvent;
import io.netty.channel.Channels;
import io.netty.channel.MessageEvent;
import io.netty.channel.SimpleChannelUpstreamHandler;
/**
* Manages streams within a SPDY session.
*/
public class SpdySessionHandler extends SimpleChannelUpstreamHandler
implements ChannelDownstreamHandler {
private static final SpdyProtocolException PROTOCOL_EXCEPTION = new SpdyProtocolException();
private final SpdySession spdySession = new SpdySession();
private volatile int lastGoodStreamID;
private volatile int remoteConcurrentStreams;
private volatile int localConcurrentStreams;
private volatile int maxConcurrentStreams;
private final AtomicInteger pings = new AtomicInteger();
private volatile boolean sentGoAwayFrame;
private volatile boolean receivedGoAwayFrame;
private volatile ChannelFuture closeSessionFuture;
private final boolean server;
/**
* Creates a new session handler.
*
* @param server {@code true} if and only if this session handler should
* handle the server endpoint of the connection.
* {@code false} if and only if this session handler should
* handle the client endpoint of the connection.
*/
public SpdySessionHandler(boolean server) {
super();
this.server = server;
}
@Override
public void messageReceived(ChannelHandlerContext ctx, MessageEvent e)
throws Exception {
Object msg = e.getMessage();
if (msg instanceof SpdyDataFrame) {
/*
* SPDY Data frame processing requirements:
*
* If an endpoint receives a data frame for a Stream-ID which does not exist,
* it must return a RST_STREAM with error code INVALID_STREAM for the Stream-ID.
*
* If an endpoint which created the stream receives a data frame before receiving
* a SYN_REPLY on that stream, it is a protocol error, and the receiver should
* close the connection immediately.
*
* If an endpoint receives multiple data frames for invalid Stream-IDs,
* it may terminate the session.
*
* If an endpoint refuses a stream it must ignore any data frames for that stream.
*
* If an endpoint receives data on a stream which has already been torn down,
* it must ignore the data received after the teardown.
*/
SpdyDataFrame spdyDataFrame = (SpdyDataFrame) msg;
int streamID = spdyDataFrame.getStreamID();
// Check if we received a data frame for a Stream-ID which is not open
if (spdySession.isRemoteSideClosed(streamID)) {
if (!sentGoAwayFrame) {
issueStreamError(ctx, e, streamID, SpdyStreamStatus.INVALID_STREAM);
}
return;
}
// Check if we received a data frame before receiving a SYN_REPLY
if (!isRemoteInitiatedID(streamID) && !spdySession.hasReceivedReply(streamID)) {
issueStreamError(ctx, e, streamID, SpdyStreamStatus.PROTOCOL_ERROR);
return;
}
if (spdyDataFrame.isLast()) {
// Close remote side of stream
halfCloseStream(streamID, true);
}
} else if (msg instanceof SpdySynStreamFrame) {
/*
* SPDY SYN_STREAM frame processing requirements:
*
* If an endpoint receives a SYN_STREAM with a Stream-ID that is not monotonically
* increasing, it must issue a session error with the status PROTOCOL_ERROR.
*
* If an endpoint receives multiple SYN_STREAM frames with the same active
* Stream-ID, it must issue a stream error with the status code PROTOCOL_ERROR.
*/
SpdySynStreamFrame spdySynStreamFrame = (SpdySynStreamFrame) msg;
int streamID = spdySynStreamFrame.getStreamID();
// Check if we received a valid SYN_STREAM frame
if (spdySynStreamFrame.isInvalid() ||
!isRemoteInitiatedID(streamID) ||
spdySession.isActiveStream(streamID)) {
issueStreamError(ctx, e, streamID, SpdyStreamStatus.PROTOCOL_ERROR);
return;
}
// Stream-IDs must be monotonically increassing
if (streamID < lastGoodStreamID) {
issueSessionError(ctx, e.getChannel(), e.getRemoteAddress());
return;
}
// Try to accept the stream
boolean remoteSideClosed = spdySynStreamFrame.isLast();
boolean localSideClosed = spdySynStreamFrame.isUnidirectional();
if (!acceptStream(streamID, remoteSideClosed, localSideClosed)) {
issueStreamError(ctx, e, streamID, SpdyStreamStatus.REFUSED_STREAM);
return;
}
} else if (msg instanceof SpdySynReplyFrame) {
/*
* SPDY SYN_REPLY frame processing requirements:
*
* If an endpoint receives multiple SYN_REPLY frames for the same active Stream-ID
* it must issue a stream error with the status code PROTOCOL_ERROR.
*/
SpdySynReplyFrame spdySynReplyFrame = (SpdySynReplyFrame) msg;
int streamID = spdySynReplyFrame.getStreamID();
// Check if we received a valid SYN_REPLY frame
if (spdySynReplyFrame.isInvalid() ||
isRemoteInitiatedID(streamID) ||
spdySession.isRemoteSideClosed(streamID)) {
issueStreamError(ctx, e, streamID, SpdyStreamStatus.INVALID_STREAM);
return;
}
// Check if we have received multiple frames for the same Stream-ID
if (spdySession.hasReceivedReply(streamID)) {
issueStreamError(ctx, e, streamID, SpdyStreamStatus.PROTOCOL_ERROR);
return;
}
spdySession.receivedReply(streamID);
if (spdySynReplyFrame.isLast()) {
// Close remote side of stream
halfCloseStream(streamID, true);
}
} else if (msg instanceof SpdyRstStreamFrame) {
/*
* SPDY RST_STREAM frame processing requirements:
*
* After receiving a RST_STREAM on a stream, the receiver must not send additional
* frames on that stream.
*/
SpdyRstStreamFrame spdyRstStreamFrame = (SpdyRstStreamFrame) msg;
removeStream(spdyRstStreamFrame.getStreamID());
} else if (msg instanceof SpdySettingsFrame) {
/*
* Only concerned with MAX_CONCURRENT_STREAMS
*/
SpdySettingsFrame spdySettingsFrame = (SpdySettingsFrame) msg;
updateConcurrentStreams(spdySettingsFrame, true);
} else if (msg instanceof SpdyPingFrame) {
/*
* SPDY PING frame processing requirements:
*
* Receivers of a PING frame should send an identical frame to the sender
* as soon as possible.
*
* Receivers of a PING frame must ignore frames that it did not initiate
*/
SpdyPingFrame spdyPingFrame = (SpdyPingFrame) msg;
if (isRemoteInitiatedID(spdyPingFrame.getID())) {
Channels.write(ctx, Channels.future(e.getChannel()), spdyPingFrame, e.getRemoteAddress());
return;
}
// Note: only checks that there are outstanding pings since uniqueness is not inforced
if (pings.get() == 0) {
return;
}
pings.getAndDecrement();
} else if (msg instanceof SpdyGoAwayFrame) {
receivedGoAwayFrame = true;
} else if (msg instanceof SpdyHeadersFrame) {
SpdyHeadersFrame spdyHeadersFrame = (SpdyHeadersFrame) msg;
int streamID = spdyHeadersFrame.getStreamID();
// Check if we received a valid HEADERS frame
if (spdyHeadersFrame.isInvalid()) {
issueStreamError(ctx, e, streamID, SpdyStreamStatus.PROTOCOL_ERROR);
return;
}
if (spdySession.isRemoteSideClosed(streamID)) {
issueStreamError(ctx, e, streamID, SpdyStreamStatus.INVALID_STREAM);
return;
}
}
super.messageReceived(ctx, e);
}
public void handleDownstream(ChannelHandlerContext ctx, ChannelEvent evt)
throws Exception {
if (evt instanceof ChannelStateEvent) {
ChannelStateEvent e = (ChannelStateEvent) evt;
switch (e.getState()) {
case OPEN:
case CONNECTED:
case BOUND:
if (Boolean.FALSE.equals(e.getValue()) || e.getValue() == null) {
sendGoAwayFrame(ctx, e);
return;
}
}
}
if (!(evt instanceof MessageEvent)) {
ctx.sendDownstream(evt);
return;
}
MessageEvent e = (MessageEvent) evt;
Object msg = e.getMessage();
if (msg instanceof SpdyDataFrame) {
SpdyDataFrame spdyDataFrame = (SpdyDataFrame) msg;
int streamID = spdyDataFrame.getStreamID();
if (spdySession.isLocalSideClosed(streamID)) {
e.getFuture().setFailure(PROTOCOL_EXCEPTION);
return;
}
if (spdyDataFrame.isLast()) {
halfCloseStream(streamID, false);
}
} else if (msg instanceof SpdySynStreamFrame) {
SpdySynStreamFrame spdySynStreamFrame = (SpdySynStreamFrame) msg;
boolean remoteSideClosed = spdySynStreamFrame.isUnidirectional();
boolean localSideClosed = spdySynStreamFrame.isLast();
if (!acceptStream(spdySynStreamFrame.getStreamID(), remoteSideClosed, localSideClosed)) {
e.getFuture().setFailure(PROTOCOL_EXCEPTION);
return;
}
} else if (msg instanceof SpdySynReplyFrame) {
SpdySynReplyFrame spdySynReplyFrame = (SpdySynReplyFrame) msg;
int streamID = spdySynReplyFrame.getStreamID();
if (!isRemoteInitiatedID(streamID) || spdySession.isLocalSideClosed(streamID)) {
e.getFuture().setFailure(PROTOCOL_EXCEPTION);
return;
}
if (spdySynReplyFrame.isLast()) {
halfCloseStream(streamID, false);
}
} else if (msg instanceof SpdyRstStreamFrame) {
SpdyRstStreamFrame spdyRstStreamFrame = (SpdyRstStreamFrame) msg;
removeStream(spdyRstStreamFrame.getStreamID());
} else if (msg instanceof SpdySettingsFrame) {
SpdySettingsFrame spdySettingsFrame = (SpdySettingsFrame) msg;
updateConcurrentStreams(spdySettingsFrame, false);
} else if (msg instanceof SpdyPingFrame) {
SpdyPingFrame spdyPingFrame = (SpdyPingFrame) msg;
if (isRemoteInitiatedID(spdyPingFrame.getID())) {
e.getFuture().setFailure(new IllegalArgumentException(
"invalid PING ID: " + spdyPingFrame.getID()));
return;
}
pings.getAndIncrement();
} else if (msg instanceof SpdyGoAwayFrame) {
// Should send a CLOSE ChannelStateEvent
e.getFuture().setFailure(PROTOCOL_EXCEPTION);
return;
} else if (msg instanceof SpdyHeadersFrame) {
SpdyHeadersFrame spdyHeadersFrame = (SpdyHeadersFrame) msg;
int streamID = spdyHeadersFrame.getStreamID();
if (spdySession.isLocalSideClosed(streamID)) {
e.getFuture().setFailure(PROTOCOL_EXCEPTION);
return;
}
}
ctx.sendDownstream(evt);
}
/*
* Error Handling
*/
private void issueSessionError(
ChannelHandlerContext ctx, Channel channel, SocketAddress remoteAddress) {
ChannelFuture future = sendGoAwayFrame(ctx, channel, remoteAddress);
future.addListener(ChannelFutureListener.CLOSE);
}
// Send a RST_STREAM frame in response to an incoming MessageEvent
// Only called in the upstream direction
private void issueStreamError(
ChannelHandlerContext ctx, MessageEvent e, int streamID, SpdyStreamStatus status) {
removeStream(streamID);
SpdyRstStreamFrame spdyRstStreamFrame = new DefaultSpdyRstStreamFrame(streamID, status);
Channels.write(ctx, Channels.future(e.getChannel()), spdyRstStreamFrame, e.getRemoteAddress());
}
/*
* Helper functions
*/
private boolean isRemoteInitiatedID(int ID) {
boolean serverID = SpdyCodecUtil.isServerID(ID);
return (server && !serverID) || (!server && serverID);
}
private synchronized void updateConcurrentStreams(SpdySettingsFrame settings, boolean remote) {
int newConcurrentStreams = settings.getValue(SpdySettingsFrame.SETTINGS_MAX_CONCURRENT_STREAMS);
if (remote) {
remoteConcurrentStreams = newConcurrentStreams;
} else {
localConcurrentStreams = newConcurrentStreams;
}
if (localConcurrentStreams == remoteConcurrentStreams) {
maxConcurrentStreams = localConcurrentStreams;
return;
}
if (localConcurrentStreams == 0) {
maxConcurrentStreams = remoteConcurrentStreams;
return;
}
if (remoteConcurrentStreams == 0) {
maxConcurrentStreams = localConcurrentStreams;
return;
}
if (localConcurrentStreams > remoteConcurrentStreams) {
maxConcurrentStreams = remoteConcurrentStreams;
} else {
maxConcurrentStreams = localConcurrentStreams;
}
}
// need to synchronize accesses to sentGoAwayFrame and lastGoodStreamID
private synchronized boolean acceptStream(
int streamID, boolean remoteSideClosed, boolean localSideClosed) {
// Cannot initiate any new streams after receiving or sending GOAWAY
if (receivedGoAwayFrame || sentGoAwayFrame) {
return false;
}
if ((maxConcurrentStreams != 0) &&
(spdySession.numActiveStreams() >= maxConcurrentStreams)) {
return false;
}
spdySession.acceptStream(streamID, remoteSideClosed, localSideClosed);
if (isRemoteInitiatedID(streamID)) {
lastGoodStreamID = streamID;
}
return true;
}
private void halfCloseStream(int streamID, boolean remote) {
if (remote) {
spdySession.closeRemoteSide(streamID);
} else {
spdySession.closeLocalSide(streamID);
}
if ((closeSessionFuture != null) && spdySession.noActiveStreams()) {
closeSessionFuture.setSuccess();
}
}
private void removeStream(int streamID) {
spdySession.removeStream(streamID);
if ((closeSessionFuture != null) && spdySession.noActiveStreams()) {
closeSessionFuture.setSuccess();
}
}
private void sendGoAwayFrame(ChannelHandlerContext ctx, ChannelStateEvent e) {
// Avoid NotYetConnectedException
if (!e.getChannel().isConnected()) {
ctx.sendDownstream(e);
return;
}
ChannelFuture future = sendGoAwayFrame(ctx, e.getChannel(), null);
if (spdySession.noActiveStreams()) {
future.addListener(new ClosingChannelFutureListener(ctx, e));
} else {
closeSessionFuture = Channels.future(e.getChannel());
closeSessionFuture.addListener(new ClosingChannelFutureListener(ctx, e));
}
}
private synchronized ChannelFuture sendGoAwayFrame(
ChannelHandlerContext ctx, Channel channel, SocketAddress remoteAddress) {
if (!sentGoAwayFrame) {
sentGoAwayFrame = true;
ChannelFuture future = Channels.future(channel);
Channels.write(ctx, future, new DefaultSpdyGoAwayFrame(lastGoodStreamID));
return future;
}
return Channels.succeededFuture(channel);
}
private static final class ClosingChannelFutureListener implements ChannelFutureListener {
private final ChannelHandlerContext ctx;
private final ChannelStateEvent e;
ClosingChannelFutureListener(ChannelHandlerContext ctx, ChannelStateEvent e) {
this.ctx = ctx;
this.e = e;
}
public void operationComplete(ChannelFuture sentGoAwayFuture) throws Exception {
if (!(sentGoAwayFuture.getCause() instanceof ClosedChannelException)) {
Channels.close(ctx, e.getFuture());
} else {
e.getFuture().setSuccess();
}
}
}
}
