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1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one
3    *  or more contributor license agreements.  See the NOTICE file
4    *  distributed with this work for additional information
5    *  regarding copyright ownership.  The ASF licenses this file
6    *  to you under the Apache License, Version 2.0 (the
7    *  "License"); you may not use this file except in compliance
8    *  with the License.  You may obtain a copy of the License at
9    *
10   *    http://www.apache.org/licenses/LICENSE-2.0
11   *
12   *  Unless required by applicable law or agreed to in writing,
13   *  software distributed under the License is distributed on an
14   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   *  KIND, either express or implied.  See the License for the
16   *  specific language governing permissions and limitations
17   *  under the License.
18   *
19   */
20  package org.apache.mina.transport.socket.nio.support;
21  
22  import java.io.IOException;
23  import java.net.InetSocketAddress;
24  import java.net.SocketAddress;
25  import java.nio.channels.DatagramChannel;
26  import java.nio.channels.SelectionKey;
27  import java.nio.channels.Selector;
28  import java.util.ArrayList;
29  import java.util.Iterator;
30  import java.util.List;
31  import java.util.Map;
32  import java.util.Queue;
33  import java.util.Set;
34  import java.util.concurrent.ConcurrentHashMap;
35  import java.util.concurrent.ConcurrentLinkedQueue;
36  import java.util.concurrent.Executor;
37  import java.util.concurrent.atomic.AtomicInteger;
38  
39  import org.apache.mina.common.ByteBuffer;
40  import org.apache.mina.common.ExceptionMonitor;
41  import org.apache.mina.common.IoAcceptor;
42  import org.apache.mina.common.IoFilter.WriteRequest;
43  import org.apache.mina.common.IoHandler;
44  import org.apache.mina.common.IoServiceConfig;
45  import org.apache.mina.common.IoSession;
46  import org.apache.mina.common.IoSessionRecycler;
47  import org.apache.mina.common.RuntimeIOException;
48  import org.apache.mina.common.support.BaseIoAcceptor;
49  import org.apache.mina.common.support.IoServiceListenerSupport;
50  import org.apache.mina.transport.socket.nio.DatagramAcceptorConfig;
51  import org.apache.mina.transport.socket.nio.DatagramServiceConfig;
52  import org.apache.mina.transport.socket.nio.DatagramSessionConfig;
53  import org.apache.mina.util.NamePreservingRunnable;
54  
55  /**
56   * {@link IoAcceptor} for datagram transport (UDP/IP).
57   *
58   * @author The Apache Directory Project (mina-dev@directory.apache.org)
59   * @version $Rev: 563373 $, $Date: 2007-08-07 11:49:24 +0900 (화, 07  8월 2007) $
60   */
61  public class DatagramAcceptorDelegate extends BaseIoAcceptor implements
62          IoAcceptor, DatagramService {
63      private static final AtomicInteger nextId = new AtomicInteger();
64  
65      private final Object lock = new Object();
66  
67      private final IoAcceptor wrapper;
68  
69      private final Executor executor;
70  
71      private final int id = nextId.getAndIncrement();
72  
73      private volatile Selector selector;
74  
75      private DatagramAcceptorConfig defaultConfig = new DatagramAcceptorConfig();
76  
77      private final Map<SocketAddress, DatagramChannel> channels = new ConcurrentHashMap<SocketAddress, DatagramChannel>();
78  
79      private final Queue<RegistrationRequest> registerQueue = new ConcurrentLinkedQueue<RegistrationRequest>();
80  
81      private final Queue<CancellationRequest> cancelQueue = new ConcurrentLinkedQueue<CancellationRequest>();
82  
83      private final Queue<DatagramSessionImpl> flushingSessions = new ConcurrentLinkedQueue<DatagramSessionImpl>();
84  
85      private Worker worker;
86  
87      /**
88       * Creates a new instance.
89       */
90      public DatagramAcceptorDelegate(IoAcceptor wrapper, Executor executor) {
91          this.wrapper = wrapper;
92          this.executor = executor;
93  
94          // The default reuseAddress of an accepted socket should be 'true'.
95          defaultConfig.getSessionConfig().setReuseAddress(true);
96      }
97  
98      public void bind(SocketAddress address, IoHandler handler,
99              IoServiceConfig config) throws IOException {
100         if (handler == null)
101             throw new NullPointerException("handler");
102         if (config == null) {
103             config = getDefaultConfig();
104         }
105 
106         if (address != null && !(address instanceof InetSocketAddress))
107             throw new IllegalArgumentException("Unexpected address type: "
108                     + address.getClass());
109 
110         RegistrationRequest request = new RegistrationRequest(address, handler,
111                 config);
112         
113         synchronized (lock) {
114             startupWorker();
115             registerQueue.add(request);
116             selector.wakeup();
117         }
118 
119         synchronized (request) {
120             while (!request.done) {
121                 try {
122                     request.wait();
123                 } catch (InterruptedException e) {
124                     throw new RuntimeIOException(e);
125                 }
126             }
127         }
128 
129         if (request.exception != null) {
130             throw (IOException) new IOException("Failed to bind")
131                     .initCause(request.exception);
132         }
133     }
134 
135     public void unbind(SocketAddress address) {
136         if (address == null)
137             throw new NullPointerException("address");
138 
139         CancellationRequest request = new CancellationRequest(address);
140         synchronized (lock) {
141             try {
142                 startupWorker();
143             } catch (IOException e) {
144                 // IOException is thrown only when Worker thread is not
145                 // running and failed to open a selector.  We simply throw
146                 // IllegalArgumentException here because we can simply
147                 // conclude that nothing is bound to the selector.
148                 throw new IllegalArgumentException("Address not bound: " + address);
149             }
150     
151             cancelQueue.add(request);
152             selector.wakeup();
153         }
154 
155         synchronized (request) {
156             while (!request.done) {
157                 try {
158                     request.wait();
159                 } catch (InterruptedException e) {
160                     throw new RuntimeIOException(e);
161                 }
162             }
163         }
164 
165         if (request.exception != null) {
166             throw new RuntimeException("Failed to unbind", request.exception);
167         }
168     }
169 
170     public void unbindAll() {
171         List<SocketAddress> addresses = new ArrayList<SocketAddress>(channels
172                 .keySet());
173 
174         for (SocketAddress address : addresses) {
175             unbind(address);
176         }
177     }
178 
179     @Override
180     public IoSession newSession(SocketAddress remoteAddress,
181             SocketAddress localAddress) {
182         if (remoteAddress == null) {
183             throw new NullPointerException("remoteAddress");
184         }
185         if (localAddress == null) {
186             throw new NullPointerException("localAddress");
187         }
188 
189         Selector selector = this.selector;
190         DatagramChannel ch = channels.get(localAddress);
191         if (selector == null || ch == null) {
192             throw new IllegalArgumentException("Unknown localAddress: "
193                     + localAddress);
194         }
195 
196         SelectionKey key = ch.keyFor(selector);
197         if (key == null) {
198             throw new IllegalArgumentException("Unknown localAddress: "
199                     + localAddress);
200         }
201 
202         RegistrationRequest req = (RegistrationRequest) key.attachment();
203         IoSession session;
204         IoSessionRecycler sessionRecycler = getSessionRecycler(req);
205         synchronized (sessionRecycler) {
206             session = sessionRecycler.recycle(localAddress, remoteAddress);
207             if (session != null) {
208                 return session;
209             }
210 
211             // If a new session needs to be created.
212             // Note that the local address is the service address in the
213             // acceptor side, and I didn't call getLocalSocketAddress().
214             // This avoids strange cases where getLocalSocketAddress() on the
215             // underlying socket would return an IPv6 address while the
216             // specified service address is an IPv4 address.
217             DatagramSessionImpl datagramSession = new DatagramSessionImpl(
218                     wrapper, this, req.config, ch, req.handler, req.address,
219                     req.address);
220             datagramSession.setRemoteAddress(remoteAddress);
221             datagramSession.setSelectionKey(key);
222 
223             getSessionRecycler(req).put(datagramSession);
224             session = datagramSession;
225         }
226 
227         try {
228             buildFilterChain(req, session);
229             getListeners().fireSessionCreated(session);
230         } catch (Throwable t) {
231             ExceptionMonitor.getInstance().exceptionCaught(t);
232         }
233 
234         return session;
235     }
236 
237     private IoSessionRecycler getSessionRecycler(RegistrationRequest req) {
238         IoSessionRecycler sessionRecycler;
239         if (req.config instanceof DatagramServiceConfig) {
240             sessionRecycler = ((DatagramServiceConfig) req.config)
241                     .getSessionRecycler();
242         } else {
243             sessionRecycler = defaultConfig.getSessionRecycler();
244         }
245         return sessionRecycler;
246     }
247 
248     @Override
249     public IoServiceListenerSupport getListeners() {
250         return super.getListeners();
251     }
252 
253     private void buildFilterChain(RegistrationRequest req, IoSession session)
254             throws Exception {
255         this.getFilterChainBuilder().buildFilterChain(session.getFilterChain());
256         req.config.getFilterChainBuilder().buildFilterChain(
257                 session.getFilterChain());
258         req.config.getThreadModel().buildFilterChain(session.getFilterChain());
259     }
260 
261     public DatagramAcceptorConfig getDefaultConfig() {
262         return defaultConfig;
263     }
264 
265     /**
266      * Sets the config this acceptor will use by default.
267      *
268      * @param defaultConfig the default config.
269      * @throws NullPointerException if the specified value is <code>null</code>.
270      */
271     public void setDefaultConfig(DatagramAcceptorConfig defaultConfig) {
272         if (defaultConfig == null) {
273             throw new NullPointerException("defaultConfig");
274         }
275         this.defaultConfig = defaultConfig;
276     }
277 
278     private void startupWorker() throws IOException {
279         synchronized (lock) {
280             if (worker == null) {
281                 selector = Selector.open();
282                 worker = new Worker();
283                 executor.execute(new NamePreservingRunnable(worker));
284             }
285         }
286     }
287 
288     public void flushSession(DatagramSessionImpl session) {
289         scheduleFlush(session);
290         Selector selector = this.selector;
291         if (selector != null) {
292             selector.wakeup();
293         }
294     }
295 
296     public void closeSession(DatagramSessionImpl session) {
297     }
298 
299     private void scheduleFlush(DatagramSessionImpl session) {
300         flushingSessions.add(session);
301     }
302 
303     private class Worker implements Runnable {
304         public void run() {
305             Thread.currentThread().setName("DatagramAcceptor-" + id);
306 
307             Selector selector = DatagramAcceptorDelegate.this.selector;
308             for (;;) {
309                 try {
310                     int nKeys = selector.select();
311 
312                     registerNew();
313 
314                     if (nKeys > 0) {
315                         processReadySessions(selector.selectedKeys());
316                     }
317 
318                     flushSessions();
319                     cancelKeys();
320 
321                     if (selector.keys().isEmpty()) {
322                         synchronized (lock) {
323                             if (selector.keys().isEmpty()
324                                     && registerQueue.isEmpty()
325                                     && cancelQueue.isEmpty()) {
326                                 worker = null;
327                                 try {
328                                     selector.close();
329                                 } catch (IOException e) {
330                                     ExceptionMonitor.getInstance()
331                                             .exceptionCaught(e);
332                                 } finally {
333                                     DatagramAcceptorDelegate.this.selector = null;
334                                 }
335                                 break;
336                             }
337                         }
338                     }
339                 } catch (IOException e) {
340                     ExceptionMonitor.getInstance().exceptionCaught(e);
341 
342                     try {
343                         Thread.sleep(1000);
344                     } catch (InterruptedException e1) {
345                         ExceptionMonitor.getInstance().exceptionCaught(e1);
346                     }
347                 }
348             }
349         }
350     }
351 
352     private void processReadySessions(Set<SelectionKey> keys) {
353         Iterator<SelectionKey> it = keys.iterator();
354         while (it.hasNext()) {
355             SelectionKey key = it.next();
356             it.remove();
357 
358             DatagramChannel ch = (DatagramChannel) key.channel();
359 
360             RegistrationRequest req = (RegistrationRequest) key.attachment();
361             try {
362                 if (key.isReadable()) {
363                     readSession(ch, req);
364                 }
365 
366                 if (key.isWritable()) {
367                     for (Object o : getManagedSessions(req.address)) {
368                         scheduleFlush((DatagramSessionImpl) o);
369                     }
370                 }
371             } catch (Throwable t) {
372                 ExceptionMonitor.getInstance().exceptionCaught(t);
373             }
374         }
375     }
376 
377     private void readSession(DatagramChannel channel, RegistrationRequest req)
378             throws Exception {
379         ByteBuffer readBuf = ByteBuffer
380                 .allocate(((DatagramSessionConfig) req.config
381                         .getSessionConfig()).getReceiveBufferSize());
382         try {
383             SocketAddress remoteAddress = channel.receive(readBuf.buf());
384             if (remoteAddress != null) {
385                 DatagramSessionImpl session = (DatagramSessionImpl) newSession(
386                         remoteAddress, req.address);
387 
388                 readBuf.flip();
389 
390                 ByteBuffer newBuf = ByteBuffer.allocate(readBuf.limit());
391                 newBuf.put(readBuf);
392                 newBuf.flip();
393 
394                 session.increaseReadBytes(newBuf.remaining());
395                 session.getFilterChain().fireMessageReceived(session, newBuf);
396             }
397         } finally {
398             readBuf.release();
399         }
400     }
401 
402     private void flushSessions() {
403         if (flushingSessions.size() == 0)
404             return;
405 
406         for (;;) {
407             DatagramSessionImpl session = flushingSessions.poll();
408 
409             if (session == null)
410                 break;
411 
412             try {
413                 flush(session);
414             } catch (IOException e) {
415                 session.getFilterChain().fireExceptionCaught(session, e);
416             }
417         }
418     }
419 
420     private void flush(DatagramSessionImpl session) throws IOException {
421         DatagramChannel ch = session.getChannel();
422 
423         Queue<WriteRequest> writeRequestQueue = session.getWriteRequestQueue();
424 
425         for (;;) {
426             WriteRequest req = writeRequestQueue.peek();
427 
428             if (req == null)
429                 break;
430 
431             ByteBuffer buf = (ByteBuffer) req.getMessage();
432             if (buf.remaining() == 0) {
433                 // pop and fire event
434                 writeRequestQueue.poll();
435 
436                 session.increaseWrittenMessages();
437                 buf.reset();
438                 session.getFilterChain().fireMessageSent(session, req);
439                 continue;
440             }
441 
442             SelectionKey key = session.getSelectionKey();
443             if (key == null) {
444                 scheduleFlush(session);
445                 break;
446             }
447             if (!key.isValid()) {
448                 continue;
449             }
450 
451             SocketAddress destination = req.getDestination();
452             if (destination == null) {
453                 destination = session.getRemoteAddress();
454             }
455 
456             int writtenBytes = ch.send(buf.buf(), destination);
457 
458             if (writtenBytes == 0) {
459                 // Kernel buffer is full
460                 key.interestOps(key.interestOps() | SelectionKey.OP_WRITE);
461             } else if (writtenBytes > 0) {
462                 key.interestOps(key.interestOps() & (~SelectionKey.OP_WRITE));
463 
464                 // pop and fire event
465                 writeRequestQueue.poll();
466 
467                 session.increaseWrittenBytes(writtenBytes);
468                 session.increaseWrittenMessages();
469                 buf.reset();
470                 session.getFilterChain().fireMessageSent(session, req);
471             }
472         }
473     }
474 
475     private void registerNew() {
476         if (registerQueue.isEmpty())
477             return;
478 
479         Selector selector = this.selector;
480         for (;;) {
481             RegistrationRequest req = registerQueue.poll();
482 
483             if (req == null)
484                 break;
485 
486             DatagramChannel ch = null;
487             try {
488                 ch = DatagramChannel.open();
489                 DatagramSessionConfig cfg;
490                 if (req.config.getSessionConfig() instanceof DatagramSessionConfig) {
491                     cfg = (DatagramSessionConfig) req.config.getSessionConfig();
492                 } else {
493                     cfg = getDefaultConfig().getSessionConfig();
494                 }
495 
496                 ch.socket().setReuseAddress(cfg.isReuseAddress());
497                 ch.socket().setBroadcast(cfg.isBroadcast());
498                 ch.socket().setReceiveBufferSize(cfg.getReceiveBufferSize());
499                 ch.socket().setSendBufferSize(cfg.getSendBufferSize());
500 
501                 if (ch.socket().getTrafficClass() != cfg.getTrafficClass()) {
502                     ch.socket().setTrafficClass(cfg.getTrafficClass());
503                 }
504 
505                 ch.configureBlocking(false);
506                 ch.socket().bind(req.address);
507                 if (req.address == null || req.address.getPort() == 0) {
508                     req.address = (InetSocketAddress) ch.socket()
509                             .getLocalSocketAddress();
510                 }
511                 ch.register(selector, SelectionKey.OP_READ, req);
512                 channels.put(req.address, ch);
513 
514                 getListeners().fireServiceActivated(this, req.address,
515                         req.handler, req.config);
516             } catch (Throwable t) {
517                 req.exception = t;
518             } finally {
519                 synchronized (req) {
520                     req.done = true;
521                     req.notify();
522                 }
523 
524                 if (ch != null && req.exception != null) {
525                     try {
526                         ch.disconnect();
527                         ch.close();
528                     } catch (Throwable e) {
529                         ExceptionMonitor.getInstance().exceptionCaught(e);
530                     }
531                 }
532             }
533         }
534     }
535 
536     private void cancelKeys() {
537         if (cancelQueue.isEmpty())
538             return;
539 
540         Selector selector = this.selector;
541         for (;;) {
542             CancellationRequest request = cancelQueue.poll();
543 
544             if (request == null) {
545                 break;
546             }
547 
548             DatagramChannel ch = channels.remove(request.address);
549 
550             // close the channel
551             try {
552                 if (ch == null) {
553                     request.exception = new IllegalArgumentException(
554                             "Address not bound: " + request.address);
555                 } else {
556                     SelectionKey key = ch.keyFor(selector);
557                     request.registrationRequest = (RegistrationRequest) key
558                             .attachment();
559                     key.cancel();
560                     selector.wakeup(); // wake up again to trigger thread death
561                     ch.disconnect();
562                     ch.close();
563                 }
564             } catch (Throwable t) {
565                 ExceptionMonitor.getInstance().exceptionCaught(t);
566             } finally {
567                 synchronized (request) {
568                     request.done = true;
569                     request.notify();
570                 }
571 
572                 if (request.exception == null) {
573                     getListeners().fireServiceDeactivated(this,
574                             request.address,
575                             request.registrationRequest.handler,
576                             request.registrationRequest.config);
577                 }
578             }
579         }
580     }
581 
582     public void updateTrafficMask(DatagramSessionImpl session) {
583         // There's no point in changing the traffic mask for sessions originating
584         // from this acceptor since new sessions are created every time data is
585         // received.
586     }
587 
588     private static class RegistrationRequest {
589         private InetSocketAddress address;
590 
591         private final IoHandler handler;
592 
593         private final IoServiceConfig config;
594 
595         private Throwable exception;
596 
597         private boolean done;
598 
599         private RegistrationRequest(SocketAddress address, IoHandler handler,
600                 IoServiceConfig config) {
601             this.address = (InetSocketAddress) address;
602             this.handler = handler;
603             this.config = config;
604         }
605     }
606 
607     private static class CancellationRequest {
608         private final SocketAddress address;
609 
610         private boolean done;
611 
612         private RegistrationRequest registrationRequest;
613 
614         private RuntimeException exception;
615 
616         private CancellationRequest(SocketAddress address) {
617             this.address = address;
618         }
619     }
620 }