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/*
* Copyright 2013 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.
*/
package io.netty.handler.codec.spdy;
import io.netty.channel.ChannelDuplexHandler;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPromise;
import io.netty.util.internal.ThrowableUtil;
import java.util.concurrent.atomic.AtomicInteger;
import static io.netty.handler.codec.spdy.SpdyCodecUtil.SPDY_SESSION_STREAM_ID;
import static io.netty.handler.codec.spdy.SpdyCodecUtil.isServerId;
import static io.netty.util.internal.ObjectUtil.checkPositiveOrZero;
/**
* Manages streams within a SPDY session.
*/
public class SpdySessionHandler extends ChannelDuplexHandler {
private static final SpdyProtocolException PROTOCOL_EXCEPTION = ThrowableUtil.unknownStackTrace(
SpdyProtocolException.newStatic(null), SpdySessionHandler.class, "handleOutboundMessage(...)");
private static final SpdyProtocolException STREAM_CLOSED = ThrowableUtil.unknownStackTrace(
SpdyProtocolException.newStatic("Stream closed"), SpdySessionHandler.class, "removeStream(...)");
private static final int DEFAULT_WINDOW_SIZE = 64 * 1024; // 64 KB default initial window size
private int initialSendWindowSize = DEFAULT_WINDOW_SIZE;
private int initialReceiveWindowSize = DEFAULT_WINDOW_SIZE;
private volatile int initialSessionReceiveWindowSize = DEFAULT_WINDOW_SIZE;
private final SpdySession spdySession = new SpdySession(initialSendWindowSize, initialReceiveWindowSize);
private int lastGoodStreamId;
private static final int DEFAULT_MAX_CONCURRENT_STREAMS = Integer.MAX_VALUE;
private int remoteConcurrentStreams = DEFAULT_MAX_CONCURRENT_STREAMS;
private int localConcurrentStreams = DEFAULT_MAX_CONCURRENT_STREAMS;
private final AtomicInteger pings = new AtomicInteger();
private boolean sentGoAwayFrame;
private boolean receivedGoAwayFrame;
private ChannelFutureListener closeSessionFutureListener;
private final boolean server;
private final int minorVersion;
/**
* Creates a new session handler.
*
* @param version the protocol version
* @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(SpdyVersion version, boolean server) {
if (version == null) {
throw new NullPointerException("version");
}
this.server = server;
minorVersion = version.getMinorVersion();
}
public void setSessionReceiveWindowSize(int sessionReceiveWindowSize) {
checkPositiveOrZero(sessionReceiveWindowSize, "sessionReceiveWindowSize");
// This will not send a window update frame immediately.
// If this value increases the allowed receive window size,
// a WINDOW_UPDATE frame will be sent when only half of the
// session window size remains during data frame processing.
// If this value decreases the allowed receive window size,
// the window will be reduced as data frames are processed.
initialSessionReceiveWindowSize = sessionReceiveWindowSize;
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
if (msg instanceof SpdyDataFrame) {
/*
* SPDY Data frame processing requirements:
*
* If an endpoint receives a data frame for a Stream-ID which is not open
* and the endpoint has not sent a GOAWAY frame, it must issue a stream error
* with the 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 recipient must
* issue a stream error with the getStatus code PROTOCOL_ERROR for the Stream-ID.
*
* If an endpoint receives multiple data frames for invalid Stream-IDs,
* it may close the session.
*
* If an endpoint refuses a stream it must ignore any data frames for that stream.
*
* If an endpoint receives a data frame after the stream is half-closed from the
* sender, it must send a RST_STREAM frame with the getStatus STREAM_ALREADY_CLOSED.
*
* If an endpoint receives a data frame after the stream is closed, it must send
* a RST_STREAM frame with the getStatus PROTOCOL_ERROR.
*/
SpdyDataFrame spdyDataFrame = (SpdyDataFrame) msg;
int streamId = spdyDataFrame.streamId();
int deltaWindowSize = -1 * spdyDataFrame.content().readableBytes();
int newSessionWindowSize =
spdySession.updateReceiveWindowSize(SPDY_SESSION_STREAM_ID, deltaWindowSize);
// Check if session window size is reduced beyond allowable lower bound
if (newSessionWindowSize < 0) {
issueSessionError(ctx, SpdySessionStatus.PROTOCOL_ERROR);
return;
}
// Send a WINDOW_UPDATE frame if less than half the session window size remains
if (newSessionWindowSize <= initialSessionReceiveWindowSize / 2) {
int sessionDeltaWindowSize = initialSessionReceiveWindowSize - newSessionWindowSize;
spdySession.updateReceiveWindowSize(SPDY_SESSION_STREAM_ID, sessionDeltaWindowSize);
SpdyWindowUpdateFrame spdyWindowUpdateFrame =
new DefaultSpdyWindowUpdateFrame(SPDY_SESSION_STREAM_ID, sessionDeltaWindowSize);
ctx.writeAndFlush(spdyWindowUpdateFrame);
}
// Check if we received a data frame for a Stream-ID which is not open
if (!spdySession.isActiveStream(streamId)) {
spdyDataFrame.release();
if (streamId <= lastGoodStreamId) {
issueStreamError(ctx, streamId, SpdyStreamStatus.PROTOCOL_ERROR);
} else if (!sentGoAwayFrame) {
issueStreamError(ctx, streamId, SpdyStreamStatus.INVALID_STREAM);
}
return;
}
// Check if we received a data frame for a stream which is half-closed
if (spdySession.isRemoteSideClosed(streamId)) {
spdyDataFrame.release();
issueStreamError(ctx, streamId, SpdyStreamStatus.STREAM_ALREADY_CLOSED);
return;
}
// Check if we received a data frame before receiving a SYN_REPLY
if (!isRemoteInitiatedId(streamId) && !spdySession.hasReceivedReply(streamId)) {
spdyDataFrame.release();
issueStreamError(ctx, streamId, SpdyStreamStatus.PROTOCOL_ERROR);
return;
}
/*
* SPDY Data frame flow control processing requirements:
*
* Recipient should not send a WINDOW_UPDATE frame as it consumes the last data frame.
*/
// Update receive window size
int newWindowSize = spdySession.updateReceiveWindowSize(streamId, deltaWindowSize);
// Window size can become negative if we sent a SETTINGS frame that reduces the
// size of the transfer window after the peer has written data frames.
// The value is bounded by the length that SETTINGS frame decrease the window.
// This difference is stored for the session when writing the SETTINGS frame
// and is cleared once we send a WINDOW_UPDATE frame.
if (newWindowSize < spdySession.getReceiveWindowSizeLowerBound(streamId)) {
spdyDataFrame.release();
issueStreamError(ctx, streamId, SpdyStreamStatus.FLOW_CONTROL_ERROR);
return;
}
// Window size became negative due to sender writing frame before receiving SETTINGS
// Send data frames upstream in initialReceiveWindowSize chunks
if (newWindowSize < 0) {
while (spdyDataFrame.content().readableBytes() > initialReceiveWindowSize) {
SpdyDataFrame partialDataFrame = new DefaultSpdyDataFrame(
streamId, spdyDataFrame.content().readRetainedSlice(initialReceiveWindowSize));
ctx.writeAndFlush(partialDataFrame);
}
}
// Send a WINDOW_UPDATE frame if less than half the stream window size remains
if (newWindowSize <= initialReceiveWindowSize / 2 && !spdyDataFrame.isLast()) {
int streamDeltaWindowSize = initialReceiveWindowSize - newWindowSize;
spdySession.updateReceiveWindowSize(streamId, streamDeltaWindowSize);
SpdyWindowUpdateFrame spdyWindowUpdateFrame =
new DefaultSpdyWindowUpdateFrame(streamId, streamDeltaWindowSize);
ctx.writeAndFlush(spdyWindowUpdateFrame);
}
// Close the remote side of the stream if this is the last frame
if (spdyDataFrame.isLast()) {
halfCloseStream(streamId, true, ctx.newSucceededFuture());
}
} else if (msg instanceof SpdySynStreamFrame) {
/*
* SPDY SYN_STREAM frame processing requirements:
*
* If an endpoint receives a SYN_STREAM with a Stream-ID that is less than
* any previously received SYN_STREAM, it must issue a session error with
* the getStatus PROTOCOL_ERROR.
*
* If an endpoint receives multiple SYN_STREAM frames with the same active
* Stream-ID, it must issue a stream error with the getStatus code PROTOCOL_ERROR.
*
* The recipient can reject a stream by sending a stream error with the
* getStatus code REFUSED_STREAM.
*/
SpdySynStreamFrame spdySynStreamFrame = (SpdySynStreamFrame) msg;
int streamId = spdySynStreamFrame.streamId();
// Check if we received a valid SYN_STREAM frame
if (spdySynStreamFrame.isInvalid() ||
!isRemoteInitiatedId(streamId) ||
spdySession.isActiveStream(streamId)) {
issueStreamError(ctx, streamId, SpdyStreamStatus.PROTOCOL_ERROR);
return;
}
// Stream-IDs must be monotonically increasing
if (streamId <= lastGoodStreamId) {
issueSessionError(ctx, SpdySessionStatus.PROTOCOL_ERROR);
return;
}
// Try to accept the stream
byte priority = spdySynStreamFrame.priority();
boolean remoteSideClosed = spdySynStreamFrame.isLast();
boolean localSideClosed = spdySynStreamFrame.isUnidirectional();
if (!acceptStream(streamId, priority, remoteSideClosed, localSideClosed)) {
issueStreamError(ctx, 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 getStatus code STREAM_IN_USE.
*/
SpdySynReplyFrame spdySynReplyFrame = (SpdySynReplyFrame) msg;
int streamId = spdySynReplyFrame.streamId();
// Check if we received a valid SYN_REPLY frame
if (spdySynReplyFrame.isInvalid() ||
isRemoteInitiatedId(streamId) ||
spdySession.isRemoteSideClosed(streamId)) {
issueStreamError(ctx, streamId, SpdyStreamStatus.INVALID_STREAM);
return;
}
// Check if we have received multiple frames for the same Stream-ID
if (spdySession.hasReceivedReply(streamId)) {
issueStreamError(ctx, streamId, SpdyStreamStatus.STREAM_IN_USE);
return;
}
spdySession.receivedReply(streamId);
// Close the remote side of the stream if this is the last frame
if (spdySynReplyFrame.isLast()) {
halfCloseStream(streamId, true, ctx.newSucceededFuture());
}
} 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.
*
* An endpoint must not send a RST_STREAM in response to a RST_STREAM.
*/
SpdyRstStreamFrame spdyRstStreamFrame = (SpdyRstStreamFrame) msg;
removeStream(spdyRstStreamFrame.streamId(), ctx.newSucceededFuture());
} else if (msg instanceof SpdySettingsFrame) {
SpdySettingsFrame spdySettingsFrame = (SpdySettingsFrame) msg;
int settingsMinorVersion = spdySettingsFrame.getValue(SpdySettingsFrame.SETTINGS_MINOR_VERSION);
if (settingsMinorVersion >= 0 && settingsMinorVersion != minorVersion) {
// Settings frame had the wrong minor version
issueSessionError(ctx, SpdySessionStatus.PROTOCOL_ERROR);
return;
}
int newConcurrentStreams =
spdySettingsFrame.getValue(SpdySettingsFrame.SETTINGS_MAX_CONCURRENT_STREAMS);
if (newConcurrentStreams >= 0) {
remoteConcurrentStreams = newConcurrentStreams;
}
// Persistence flag are inconsistent with the use of SETTINGS to communicate
// the initial window size. Remove flags from the sender requesting that the
// value be persisted. Remove values that the sender indicates are persisted.
if (spdySettingsFrame.isPersisted(SpdySettingsFrame.SETTINGS_INITIAL_WINDOW_SIZE)) {
spdySettingsFrame.removeValue(SpdySettingsFrame.SETTINGS_INITIAL_WINDOW_SIZE);
}
spdySettingsFrame.setPersistValue(SpdySettingsFrame.SETTINGS_INITIAL_WINDOW_SIZE, false);
int newInitialWindowSize =
spdySettingsFrame.getValue(SpdySettingsFrame.SETTINGS_INITIAL_WINDOW_SIZE);
if (newInitialWindowSize >= 0) {
updateInitialSendWindowSize(newInitialWindowSize);
}
} 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.id())) {
ctx.writeAndFlush(spdyPingFrame);
return;
}
// Note: only checks that there are outstanding pings since uniqueness is not enforced
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.streamId();
// Check if we received a valid HEADERS frame
if (spdyHeadersFrame.isInvalid()) {
issueStreamError(ctx, streamId, SpdyStreamStatus.PROTOCOL_ERROR);
return;
}
if (spdySession.isRemoteSideClosed(streamId)) {
issueStreamError(ctx, streamId, SpdyStreamStatus.INVALID_STREAM);
return;
}
// Close the remote side of the stream if this is the last frame
if (spdyHeadersFrame.isLast()) {
halfCloseStream(streamId, true, ctx.newSucceededFuture());
}
} else if (msg instanceof SpdyWindowUpdateFrame) {
/*
* SPDY WINDOW_UPDATE frame processing requirements:
*
* Receivers of a WINDOW_UPDATE that cause the window size to exceed 2^31
* must send a RST_STREAM with the getStatus code FLOW_CONTROL_ERROR.
*
* Sender should ignore all WINDOW_UPDATE frames associated with a stream
* after sending the last frame for the stream.
*/
SpdyWindowUpdateFrame spdyWindowUpdateFrame = (SpdyWindowUpdateFrame) msg;
int streamId = spdyWindowUpdateFrame.streamId();
int deltaWindowSize = spdyWindowUpdateFrame.deltaWindowSize();
// Ignore frames for half-closed streams
if (streamId != SPDY_SESSION_STREAM_ID && spdySession.isLocalSideClosed(streamId)) {
return;
}
// Check for numerical overflow
if (spdySession.getSendWindowSize(streamId) > Integer.MAX_VALUE - deltaWindowSize) {
if (streamId == SPDY_SESSION_STREAM_ID) {
issueSessionError(ctx, SpdySessionStatus.PROTOCOL_ERROR);
} else {
issueStreamError(ctx, streamId, SpdyStreamStatus.FLOW_CONTROL_ERROR);
}
return;
}
updateSendWindowSize(ctx, streamId, deltaWindowSize);
}
ctx.fireChannelRead(msg);
}
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
for (Integer streamId: spdySession.activeStreams().keySet()) {
removeStream(streamId, ctx.newSucceededFuture());
}
ctx.fireChannelInactive();
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
if (cause instanceof SpdyProtocolException) {
issueSessionError(ctx, SpdySessionStatus.PROTOCOL_ERROR);
}
ctx.fireExceptionCaught(cause);
}
@Override
public void close(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception {
sendGoAwayFrame(ctx, promise);
}
@Override
public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
if (msg instanceof SpdyDataFrame ||
msg instanceof SpdySynStreamFrame ||
msg instanceof SpdySynReplyFrame ||
msg instanceof SpdyRstStreamFrame ||
msg instanceof SpdySettingsFrame ||
msg instanceof SpdyPingFrame ||
msg instanceof SpdyGoAwayFrame ||
msg instanceof SpdyHeadersFrame ||
msg instanceof SpdyWindowUpdateFrame) {
handleOutboundMessage(ctx, msg, promise);
} else {
ctx.write(msg, promise);
}
}
private void handleOutboundMessage(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
if (msg instanceof SpdyDataFrame) {
SpdyDataFrame spdyDataFrame = (SpdyDataFrame) msg;
int streamId = spdyDataFrame.streamId();
// Frames must not be sent on half-closed streams
if (spdySession.isLocalSideClosed(streamId)) {
spdyDataFrame.release();
promise.setFailure(PROTOCOL_EXCEPTION);
return;
}
/*
* SPDY Data frame flow control processing requirements:
*
* Sender must not send a data frame with data length greater
* than the transfer window size.
*
* After sending each data frame, the sender decrements its
* transfer window size by the amount of data transmitted.
*
* When the window size becomes less than or equal to 0, the
* sender must pause transmitting data frames.
*/
int dataLength = spdyDataFrame.content().readableBytes();
int sendWindowSize = spdySession.getSendWindowSize(streamId);
int sessionSendWindowSize = spdySession.getSendWindowSize(SPDY_SESSION_STREAM_ID);
sendWindowSize = Math.min(sendWindowSize, sessionSendWindowSize);
if (sendWindowSize <= 0) {
// Stream is stalled -- enqueue Data frame and return
spdySession.putPendingWrite(streamId, new SpdySession.PendingWrite(spdyDataFrame, promise));
return;
} else if (sendWindowSize < dataLength) {
// Stream is not stalled but we cannot send the entire frame
spdySession.updateSendWindowSize(streamId, -1 * sendWindowSize);
spdySession.updateSendWindowSize(SPDY_SESSION_STREAM_ID, -1 * sendWindowSize);
// Create a partial data frame whose length is the current window size
SpdyDataFrame partialDataFrame = new DefaultSpdyDataFrame(
streamId, spdyDataFrame.content().readRetainedSlice(sendWindowSize));
// Enqueue the remaining data (will be the first frame queued)
spdySession.putPendingWrite(streamId, new SpdySession.PendingWrite(spdyDataFrame, promise));
// The transfer window size is pre-decremented when sending a data frame downstream.
// Close the session on write failures that leave the transfer window in a corrupt state.
final ChannelHandlerContext context = ctx;
ctx.write(partialDataFrame).addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
if (!future.isSuccess()) {
issueSessionError(context, SpdySessionStatus.INTERNAL_ERROR);
}
}
});
return;
} else {
// Window size is large enough to send entire data frame
spdySession.updateSendWindowSize(streamId, -1 * dataLength);
spdySession.updateSendWindowSize(SPDY_SESSION_STREAM_ID, -1 * dataLength);
// The transfer window size is pre-decremented when sending a data frame downstream.
// Close the session on write failures that leave the transfer window in a corrupt state.
final ChannelHandlerContext context = ctx;
promise.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
if (!future.isSuccess()) {
issueSessionError(context, SpdySessionStatus.INTERNAL_ERROR);
}
}
});
}
// Close the local side of the stream if this is the last frame
if (spdyDataFrame.isLast()) {
halfCloseStream(streamId, false, promise);
}
} else if (msg instanceof SpdySynStreamFrame) {
SpdySynStreamFrame spdySynStreamFrame = (SpdySynStreamFrame) msg;
int streamId = spdySynStreamFrame.streamId();
if (isRemoteInitiatedId(streamId)) {
promise.setFailure(PROTOCOL_EXCEPTION);
return;
}
byte priority = spdySynStreamFrame.priority();
boolean remoteSideClosed = spdySynStreamFrame.isUnidirectional();
boolean localSideClosed = spdySynStreamFrame.isLast();
if (!acceptStream(streamId, priority, remoteSideClosed, localSideClosed)) {
promise.setFailure(PROTOCOL_EXCEPTION);
return;
}
} else if (msg instanceof SpdySynReplyFrame) {
SpdySynReplyFrame spdySynReplyFrame = (SpdySynReplyFrame) msg;
int streamId = spdySynReplyFrame.streamId();
// Frames must not be sent on half-closed streams
if (!isRemoteInitiatedId(streamId) || spdySession.isLocalSideClosed(streamId)) {
promise.setFailure(PROTOCOL_EXCEPTION);
return;
}
// Close the local side of the stream if this is the last frame
if (spdySynReplyFrame.isLast()) {
halfCloseStream(streamId, false, promise);
}
} else if (msg instanceof SpdyRstStreamFrame) {
SpdyRstStreamFrame spdyRstStreamFrame = (SpdyRstStreamFrame) msg;
removeStream(spdyRstStreamFrame.streamId(), promise);
} else if (msg instanceof SpdySettingsFrame) {
SpdySettingsFrame spdySettingsFrame = (SpdySettingsFrame) msg;
int settingsMinorVersion = spdySettingsFrame.getValue(SpdySettingsFrame.SETTINGS_MINOR_VERSION);
if (settingsMinorVersion >= 0 && settingsMinorVersion != minorVersion) {
// Settings frame had the wrong minor version
promise.setFailure(PROTOCOL_EXCEPTION);
return;
}
int newConcurrentStreams =
spdySettingsFrame.getValue(SpdySettingsFrame.SETTINGS_MAX_CONCURRENT_STREAMS);
if (newConcurrentStreams >= 0) {
localConcurrentStreams = newConcurrentStreams;
}
// Persistence flag are inconsistent with the use of SETTINGS to communicate
// the initial window size. Remove flags from the sender requesting that the
// value be persisted. Remove values that the sender indicates are persisted.
if (spdySettingsFrame.isPersisted(SpdySettingsFrame.SETTINGS_INITIAL_WINDOW_SIZE)) {
spdySettingsFrame.removeValue(SpdySettingsFrame.SETTINGS_INITIAL_WINDOW_SIZE);
}
spdySettingsFrame.setPersistValue(SpdySettingsFrame.SETTINGS_INITIAL_WINDOW_SIZE, false);
int newInitialWindowSize =
spdySettingsFrame.getValue(SpdySettingsFrame.SETTINGS_INITIAL_WINDOW_SIZE);
if (newInitialWindowSize >= 0) {
updateInitialReceiveWindowSize(newInitialWindowSize);
}
} else if (msg instanceof SpdyPingFrame) {
SpdyPingFrame spdyPingFrame = (SpdyPingFrame) msg;
if (isRemoteInitiatedId(spdyPingFrame.id())) {
ctx.fireExceptionCaught(new IllegalArgumentException(
"invalid PING ID: " + spdyPingFrame.id()));
return;
}
pings.getAndIncrement();
} else if (msg instanceof SpdyGoAwayFrame) {
// Why is this being sent? Intercept it and fail the write.
// Should have sent a CLOSE ChannelStateEvent
promise.setFailure(PROTOCOL_EXCEPTION);
return;
} else if (msg instanceof SpdyHeadersFrame) {
SpdyHeadersFrame spdyHeadersFrame = (SpdyHeadersFrame) msg;
int streamId = spdyHeadersFrame.streamId();
// Frames must not be sent on half-closed streams
if (spdySession.isLocalSideClosed(streamId)) {
promise.setFailure(PROTOCOL_EXCEPTION);
return;
}
// Close the local side of the stream if this is the last frame
if (spdyHeadersFrame.isLast()) {
halfCloseStream(streamId, false, promise);
}
} else if (msg instanceof SpdyWindowUpdateFrame) {
// Why is this being sent? Intercept it and fail the write.
promise.setFailure(PROTOCOL_EXCEPTION);
return;
}
ctx.write(msg, promise);
}
/*
* SPDY Session Error Handling:
*
* When a session error occurs, the endpoint encountering the error must first
* send a GOAWAY frame with the Stream-ID of the most recently received stream
* from the remote endpoint, and the error code for why the session is terminating.
*
* After sending the GOAWAY frame, the endpoint must close the TCP connection.
*/
private void issueSessionError(
ChannelHandlerContext ctx, SpdySessionStatus status) {
sendGoAwayFrame(ctx, status).addListener(new ClosingChannelFutureListener(ctx, ctx.newPromise()));
}
/*
* SPDY Stream Error Handling:
*
* Upon a stream error, the endpoint must send a RST_STREAM frame which contains
* the Stream-ID for the stream where the error occurred and the error getStatus which
* caused the error.
*
* After sending the RST_STREAM, the stream is closed to the sending endpoint.
*
* Note: this is only called by the worker thread
*/
private void issueStreamError(ChannelHandlerContext ctx, int streamId, SpdyStreamStatus status) {
boolean fireChannelRead = !spdySession.isRemoteSideClosed(streamId);
ChannelPromise promise = ctx.newPromise();
removeStream(streamId, promise);
SpdyRstStreamFrame spdyRstStreamFrame = new DefaultSpdyRstStreamFrame(streamId, status);
ctx.writeAndFlush(spdyRstStreamFrame, promise);
if (fireChannelRead) {
ctx.fireChannelRead(spdyRstStreamFrame);
}
}
/*
* Helper functions
*/
private boolean isRemoteInitiatedId(int id) {
boolean serverId = isServerId(id);
return server && !serverId || !server && serverId;
}
// need to synchronize to prevent new streams from being created while updating active streams
private void updateInitialSendWindowSize(int newInitialWindowSize) {
int deltaWindowSize = newInitialWindowSize - initialSendWindowSize;
initialSendWindowSize = newInitialWindowSize;
spdySession.updateAllSendWindowSizes(deltaWindowSize);
}
// need to synchronize to prevent new streams from being created while updating active streams
private void updateInitialReceiveWindowSize(int newInitialWindowSize) {
int deltaWindowSize = newInitialWindowSize - initialReceiveWindowSize;
initialReceiveWindowSize = newInitialWindowSize;
spdySession.updateAllReceiveWindowSizes(deltaWindowSize);
}
// need to synchronize accesses to sentGoAwayFrame, lastGoodStreamId, and initial window sizes
private boolean acceptStream(
int streamId, byte priority, boolean remoteSideClosed, boolean localSideClosed) {
// Cannot initiate any new streams after receiving or sending GOAWAY
if (receivedGoAwayFrame || sentGoAwayFrame) {
return false;
}
boolean remote = isRemoteInitiatedId(streamId);
int maxConcurrentStreams = remote ? localConcurrentStreams : remoteConcurrentStreams;
if (spdySession.numActiveStreams(remote) >= maxConcurrentStreams) {
return false;
}
spdySession.acceptStream(
streamId, priority, remoteSideClosed, localSideClosed,
initialSendWindowSize, initialReceiveWindowSize, remote);
if (remote) {
lastGoodStreamId = streamId;
}
return true;
}
private void halfCloseStream(int streamId, boolean remote, ChannelFuture future) {
if (remote) {
spdySession.closeRemoteSide(streamId, isRemoteInitiatedId(streamId));
} else {
spdySession.closeLocalSide(streamId, isRemoteInitiatedId(streamId));
}
if (closeSessionFutureListener != null && spdySession.noActiveStreams()) {
future.addListener(closeSessionFutureListener);
}
}
private void removeStream(int streamId, ChannelFuture future) {
spdySession.removeStream(streamId, STREAM_CLOSED, isRemoteInitiatedId(streamId));
if (closeSessionFutureListener != null && spdySession.noActiveStreams()) {
future.addListener(closeSessionFutureListener);
}
}
private void updateSendWindowSize(final ChannelHandlerContext ctx, int streamId, int deltaWindowSize) {
spdySession.updateSendWindowSize(streamId, deltaWindowSize);
while (true) {
// Check if we have unblocked a stalled stream
SpdySession.PendingWrite pendingWrite = spdySession.getPendingWrite(streamId);
if (pendingWrite == null) {
return;
}
SpdyDataFrame spdyDataFrame = pendingWrite.spdyDataFrame;
int dataFrameSize = spdyDataFrame.content().readableBytes();
int writeStreamId = spdyDataFrame.streamId();
int sendWindowSize = spdySession.getSendWindowSize(writeStreamId);
int sessionSendWindowSize = spdySession.getSendWindowSize(SPDY_SESSION_STREAM_ID);
sendWindowSize = Math.min(sendWindowSize, sessionSendWindowSize);
if (sendWindowSize <= 0) {
return;
} else if (sendWindowSize < dataFrameSize) {
// We can send a partial frame
spdySession.updateSendWindowSize(writeStreamId, -1 * sendWindowSize);
spdySession.updateSendWindowSize(SPDY_SESSION_STREAM_ID, -1 * sendWindowSize);
// Create a partial data frame whose length is the current window size
SpdyDataFrame partialDataFrame = new DefaultSpdyDataFrame(
writeStreamId, spdyDataFrame.content().readRetainedSlice(sendWindowSize));
// The transfer window size is pre-decremented when sending a data frame downstream.
// Close the session on write failures that leave the transfer window in a corrupt state.
ctx.writeAndFlush(partialDataFrame).addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
if (!future.isSuccess()) {
issueSessionError(ctx, SpdySessionStatus.INTERNAL_ERROR);
}
}
});
} else {
// Window size is large enough to send entire data frame
spdySession.removePendingWrite(writeStreamId);
spdySession.updateSendWindowSize(writeStreamId, -1 * dataFrameSize);
spdySession.updateSendWindowSize(SPDY_SESSION_STREAM_ID, -1 * dataFrameSize);
// Close the local side of the stream if this is the last frame
if (spdyDataFrame.isLast()) {
halfCloseStream(writeStreamId, false, pendingWrite.promise);
}
// The transfer window size is pre-decremented when sending a data frame downstream.
// Close the session on write failures that leave the transfer window in a corrupt state.
ctx.writeAndFlush(spdyDataFrame, pendingWrite.promise).addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
if (!future.isSuccess()) {
issueSessionError(ctx, SpdySessionStatus.INTERNAL_ERROR);
}
}
});
}
}
}
private void sendGoAwayFrame(ChannelHandlerContext ctx, ChannelPromise future) {
// Avoid NotYetConnectedException
if (!ctx.channel().isActive()) {
ctx.close(future);
return;
}
ChannelFuture f = sendGoAwayFrame(ctx, SpdySessionStatus.OK);
if (spdySession.noActiveStreams()) {
f.addListener(new ClosingChannelFutureListener(ctx, future));
} else {
closeSessionFutureListener = new ClosingChannelFutureListener(ctx, future);
}
// FIXME: Close the connection forcibly after timeout.
}
private ChannelFuture sendGoAwayFrame(
ChannelHandlerContext ctx, SpdySessionStatus status) {
if (!sentGoAwayFrame) {
sentGoAwayFrame = true;
SpdyGoAwayFrame spdyGoAwayFrame = new DefaultSpdyGoAwayFrame(lastGoodStreamId, status);
return ctx.writeAndFlush(spdyGoAwayFrame);
} else {
return ctx.newSucceededFuture();
}
}
private static final class ClosingChannelFutureListener implements ChannelFutureListener {
private final ChannelHandlerContext ctx;
private final ChannelPromise promise;
ClosingChannelFutureListener(ChannelHandlerContext ctx, ChannelPromise promise) {
this.ctx = ctx;
this.promise = promise;
}
@Override
public void operationComplete(ChannelFuture sentGoAwayFuture) throws Exception {
ctx.close(promise);
}
}
}
