2 * Copyright (c) 2015 Cisco Systems, Inc. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
9 package org.opendaylight.openflowjava.protocol.impl.core.connection;
11 import com.google.common.base.Preconditions;
12 import io.netty.channel.ChannelHandlerContext;
13 import io.netty.channel.ChannelInboundHandlerAdapter;
14 import io.netty.util.concurrent.Future;
15 import io.netty.util.concurrent.GenericFutureListener;
16 import java.net.InetSocketAddress;
17 import java.util.concurrent.TimeUnit;
18 import java.util.concurrent.atomic.AtomicBoolean;
19 import javax.annotation.Nonnull;
20 import org.opendaylight.openflowjava.protocol.api.connection.OutboundQueueHandler;
21 import org.opendaylight.yang.gen.v1.urn.opendaylight.openflow.protocol.rev130731.EchoReplyInput;
22 import org.opendaylight.yang.gen.v1.urn.opendaylight.openflow.protocol.rev130731.EchoReplyInputBuilder;
23 import org.opendaylight.yang.gen.v1.urn.opendaylight.openflow.protocol.rev130731.EchoRequestMessage;
24 import org.opendaylight.yang.gen.v1.urn.opendaylight.openflow.protocol.rev130731.OfHeader;
25 import org.slf4j.Logger;
26 import org.slf4j.LoggerFactory;
29 * Class capsulate basic processing for stacking requests for netty channel
30 * and provide functionality for pairing request/response device message communication.
32 abstract class AbstractOutboundQueueManager<T extends OutboundQueueHandler, O extends AbstractStackedOutboundQueue>
33 extends ChannelInboundHandlerAdapter
34 implements AutoCloseable {
36 private static final Logger LOG = LoggerFactory.getLogger(AbstractOutboundQueueManager.class);
38 private static enum PipelineState {
40 * Netty thread is potentially idle, no assumptions
41 * can be made about its state.
45 * Netty thread is currently reading, once the read completes,
46 * if will flush the queue in the {@link #WRITING} state.
50 * Netty thread is currently performing a flush on the queue.
51 * It will then transition to {@link #IDLE} state.
57 * Default low write watermark. Channel will become writable when number of outstanding
58 * bytes dips below this value.
60 private static final int DEFAULT_LOW_WATERMARK = 128 * 1024;
63 * Default write high watermark. Channel will become un-writable when number of
64 * outstanding bytes hits this value.
66 private static final int DEFAULT_HIGH_WATERMARK = DEFAULT_LOW_WATERMARK * 2;
68 private final AtomicBoolean flushScheduled = new AtomicBoolean();
69 protected final ConnectionAdapterImpl parent;
70 protected final InetSocketAddress address;
71 protected final O currentQueue;
72 private final T handler;
74 // Accessed concurrently
75 private volatile PipelineState state = PipelineState.IDLE;
77 // Updated from netty only
78 private boolean alreadyReading;
79 protected boolean shuttingDown;
81 // Passed to executor to request triggering of flush
82 protected final Runnable flushRunnable = new Runnable() {
89 AbstractOutboundQueueManager(final ConnectionAdapterImpl parent, final InetSocketAddress address, final T handler) {
90 this.parent = Preconditions.checkNotNull(parent);
91 this.handler = Preconditions.checkNotNull(handler);
92 this.address = address;
93 /* Note: don't wish to use reflection here */
94 currentQueue = initializeStackedOutboudnqueue();
95 LOG.debug("Queue manager instantiated with queue {}", currentQueue);
97 handler.onConnectionQueueChanged(currentQueue);
101 * Method has to initialize some child of {@link AbstractStackedOutboundQueue}
103 * @return correct implementation of StacketOutboundqueue
105 protected abstract O initializeStackedOutboudnqueue();
108 public void close() {
109 handler.onConnectionQueueChanged(null);
113 public String toString() {
114 return String.format("Channel %s queue [flushing=%s]", parent.getChannel(), flushScheduled.get());
118 public void handlerAdded(final ChannelHandlerContext ctx) throws Exception {
120 * Tune channel write buffering. We increase the writability window
121 * to ensure we can flush an entire queue segment in one go. We definitely
122 * want to keep the difference above 64k, as that will ensure we use jam-packed
123 * TCP packets. UDP will fragment as appropriate.
125 ctx.channel().config().setWriteBufferHighWaterMark(DEFAULT_HIGH_WATERMARK);
126 ctx.channel().config().setWriteBufferLowWaterMark(DEFAULT_LOW_WATERMARK);
128 super.handlerAdded(ctx);
132 public void channelActive(final ChannelHandlerContext ctx) throws Exception {
133 super.channelActive(ctx);
138 public void channelReadComplete(final ChannelHandlerContext ctx) throws Exception {
139 super.channelReadComplete(ctx);
141 // Run flush regardless of writability. This is not strictly required, as
142 // there may be a scheduled flush. Instead of canceling it, which is expensive,
143 // we'll steal its work. Note that more work may accumulate in the time window
144 // between now and when the task will run, so it may not be a no-op after all.
146 // The reason for this is to fill the output buffer before we go into selection
147 // phase. This will make sure the pipe is full (in which case our next wake up
148 // will be the queue becoming writable).
150 alreadyReading = false;
154 public void channelWritabilityChanged(final ChannelHandlerContext ctx) throws Exception {
155 super.channelWritabilityChanged(ctx);
157 // The channel is writable again. There may be a flush task on the way, but let's
158 // steal its work, potentially decreasing latency. Since there is a window between
159 // now and when it will run, it may still pick up some more work to do.
160 LOG.debug("Channel {} writability changed, invoking flush", parent.getChannel());
165 public void channelInactive(final ChannelHandlerContext ctx) throws Exception {
166 // First of all, delegates disconnect event notification into ConnectionAdapter -> OF Plugin -> queue.close()
167 // -> queueHandler.onConnectionQueueChanged(null). The last call causes that no more entries are enqueued
169 super.channelInactive(ctx);
171 LOG.debug("Channel {} initiating shutdown...", ctx.channel());
173 // Then we start queue shutdown, start counting written messages (so that we don't keep sending messages
174 // indefinitely) and failing not completed entries.
176 final long entries = currentQueue.startShutdown();
177 LOG.debug("Cleared {} queue entries from channel {}", entries, ctx.channel());
179 // Finally, we schedule flush task that will take care of unflushed entries. We also cover the case,
180 // when there is more than shutdownOffset messages enqueued in unflushed segments
181 // (AbstractStackedOutboundQueue#finishShutdown()).
186 public void channelRead(final ChannelHandlerContext ctx, final Object msg) throws Exception {
187 // Netty does not provide a 'start reading' callback, so this is our first
188 // (and repeated) chance to detect reading. Since this callback can be invoked
189 // multiple times, we keep a boolean we check. That prevents a volatile write
190 // on repeated invocations. It will be cleared in channelReadComplete().
191 if (!alreadyReading) {
192 alreadyReading = true;
193 state = PipelineState.READING;
195 super.channelRead(ctx, msg);
199 * Invoked whenever a message comes in from the switch. Runs matching
200 * on all active queues in an attempt to complete a previous request.
202 * @param message Potential response message
203 * @return True if the message matched a previous request, false otherwise.
205 boolean onMessage(final OfHeader message) {
206 LOG.trace("Attempting to pair message {} to a request", message);
208 return currentQueue.pairRequest(message);
215 void ensureFlushing() {
216 // If the channel is not writable, there's no point in waking up,
217 // once we become writable, we will run a full flush
218 if (!parent.getChannel().isWritable()) {
222 // We are currently reading something, just a quick sync to ensure we will in fact
224 final PipelineState localState = state;
225 LOG.debug("Synchronize on pipeline state {}", localState);
226 switch (localState) {
228 // Netty thread is currently reading, it will flush the pipeline once it
229 // finishes reading. This is a no-op situation.
234 // We cannot rely on the change being flushed, schedule a request
240 * Method immediately response on Echo message.
242 * @param message incoming Echo message from device
244 void onEchoRequest(final EchoRequestMessage message) {
245 final EchoReplyInput reply = new EchoReplyInputBuilder().setData(message.getData())
246 .setVersion(message.getVersion()).setXid(message.getXid()).build();
247 parent.getChannel().writeAndFlush(makeMessageListenerWrapper(reply));
251 * Wraps outgoing message and includes listener attached to this message
252 * which is send to OFEncoder for serialization. Correct wrapper is
253 * selected by communication pipeline.
258 void writeMessage(final OfHeader message, final long now) {
259 final Object wrapper = makeMessageListenerWrapper(message);
260 parent.getChannel().write(wrapper);
264 * Wraps outgoing message and includes listener attached to this message
265 * which is send to OFEncoder for serialization. Correct wrapper is
266 * selected by communication pipeline.
270 protected Object makeMessageListenerWrapper(@Nonnull final OfHeader msg) {
271 Preconditions.checkArgument(msg != null);
273 if (address == null) {
274 return new MessageListenerWrapper(msg, LOG_ENCODER_LISTENER);
276 return new UdpMessageListenerWrapper(msg, LOG_ENCODER_LISTENER, address);
279 /* NPE are coming from {@link OFEncoder#encode} from catch block and we don't wish to lost it */
280 private static final GenericFutureListener<Future<Void>> LOG_ENCODER_LISTENER = new GenericFutureListener<Future<Void>>() {
282 private final Logger LOG = LoggerFactory.getLogger(GenericFutureListener.class);
285 public void operationComplete(final Future<Void> future) throws Exception {
286 if (future.cause() != null) {
287 LOG.warn("Message encoding fail !", future.cause());
293 * Perform a single flush operation. We keep it here so we do not generate
294 * syntetic accessors for private fields. Otherwise it could be moved into {@link #flushRunnable}.
296 protected void flush() {
297 // If the channel is gone, just flush whatever is not completed
299 LOG.trace("Dequeuing messages to channel {}", parent.getChannel());
302 } else if (currentQueue.finishShutdown(parent.getChannel())) {
304 LOG.debug("Channel {} shutdown complete", parent.getChannel());
306 LOG.trace("Channel {} current queue not completely flushed yet", parent.getChannel());
311 private void scheduleFlush() {
312 if (flushScheduled.compareAndSet(false, true)) {
313 LOG.trace("Scheduling flush task on channel {}", parent.getChannel());
314 parent.getChannel().eventLoop().execute(flushRunnable);
316 LOG.trace("Flush task is already present on channel {}", parent.getChannel());
320 private void writeAndFlush() {
321 state = PipelineState.WRITING;
323 final long start = System.nanoTime();
325 final int entries = currentQueue.writeEntries(parent.getChannel(), start);
327 LOG.trace("Flushing channel {}", parent.getChannel());
328 parent.getChannel().flush();
331 if (LOG.isDebugEnabled()) {
332 final long stop = System.nanoTime();
333 LOG.debug("Flushed {} messages to channel {} in {}us", entries, parent.getChannel(),
334 TimeUnit.NANOSECONDS.toMicros(stop - start));
337 state = PipelineState.IDLE;
340 private void rescheduleFlush() {
342 * We are almost ready to terminate. This is a bit tricky, because
343 * we do not want to have a race window where a message would be
344 * stuck on the queue without a flush being scheduled.
345 * So we mark ourselves as not running and then re-check if a
346 * flush out is needed. That will re-synchronized with other threads
347 * such that only one flush is scheduled at any given time.
349 if (!flushScheduled.compareAndSet(true, false)) {
350 LOG.warn("Channel {} queue {} flusher found unscheduled", parent.getChannel(), this);
357 * Schedule a queue flush if it is not empty and the channel is found
358 * to be writable. May only be called from Netty context.
360 private void conditionalFlush() {
361 if (currentQueue.needsFlush()) {
362 if (shuttingDown || parent.getChannel().isWritable()) {
365 LOG.debug("Channel {} is not I/O ready, not scheduling a flush", parent.getChannel());
368 LOG.trace("Queue is empty, no flush needed");