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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.HashMap;
30  import java.util.Iterator;
31  import java.util.List;
32  import java.util.Map;
33  import java.util.Set;
34  
35  import org.apache.mina.common.ByteBuffer;
36  import org.apache.mina.common.ExceptionMonitor;
37  import org.apache.mina.common.IoAcceptor;
38  import org.apache.mina.common.IoHandler;
39  import org.apache.mina.common.IoServiceConfig;
40  import org.apache.mina.common.IoSession;
41  import org.apache.mina.common.IoSessionRecycler;
42  import org.apache.mina.common.IoFilter.WriteRequest;
43  import org.apache.mina.common.support.BaseIoAcceptor;
44  import org.apache.mina.common.support.IoServiceListenerSupport;
45  import org.apache.mina.transport.socket.nio.DatagramAcceptorConfig;
46  import org.apache.mina.transport.socket.nio.DatagramServiceConfig;
47  import org.apache.mina.transport.socket.nio.DatagramSessionConfig;
48  import org.apache.mina.util.NamePreservingRunnable;
49  import org.apache.mina.util.Queue;
50  
51  import edu.emory.mathcs.backport.java.util.concurrent.Executor;
52  
53  /**
54   * {@link IoAcceptor} for datagram transport (UDP/IP).
55   * 
56   * @author The Apache Directory Project (mina-dev@directory.apache.org)
57   * @version $Rev: 563373 $, $Date: 2007-08-07 11:49:24 +0900 (화, 07  8월 2007) $
58   */
59  public class DatagramAcceptorDelegate extends BaseIoAcceptor implements
60          IoAcceptor, DatagramService {
61      private static volatile int nextId = 0;
62  
63      private final IoAcceptor wrapper;
64  
65      private final Executor executor;
66  
67      private final int id = nextId++;
68  
69      private Selector selector;
70  
71      private DatagramAcceptorConfig defaultConfig = new DatagramAcceptorConfig();
72  
73      private final Map channels = new HashMap();
74  
75      private final Queue registerQueue = new Queue();
76  
77      private final Queue cancelQueue = new Queue();
78  
79      private final Queue flushingSessions = new Queue();
80  
81      private Worker worker;
82  
83      /**
84       * Creates a new instance.
85       */
86      public DatagramAcceptorDelegate(IoAcceptor wrapper, Executor executor) {
87          this.wrapper = wrapper;
88          this.executor = executor;
89  
90          // The default reuseAddress of an accepted socket should be 'true'.
91          ((DatagramSessionConfig) defaultConfig.getSessionConfig())
92                  .setReuseAddress(true);
93      }
94  
95      public void bind(SocketAddress address, IoHandler handler,
96              IoServiceConfig config) throws IOException {
97          if (handler == null)
98              throw new NullPointerException("handler");
99          if (config == null) {
100             config = getDefaultConfig();
101         }
102 
103         if (address != null && !(address instanceof InetSocketAddress))
104             throw new IllegalArgumentException("Unexpected address type: "
105                     + address.getClass());
106 
107         RegistrationRequest request = new RegistrationRequest(address, handler,
108                 config);
109         synchronized (this) {
110             synchronized (registerQueue) {
111                 registerQueue.push(request);
112             }
113             startupWorker();
114             selector.wakeup();
115         }
116 
117         synchronized (request) {
118             while (!request.done) {
119                 try {
120                     request.wait();
121                 } catch (InterruptedException e) {
122                 }
123             }
124         }
125 
126         if (request.exception != null) {
127             throw (IOException) new IOException("Failed to bind")
128                     .initCause(request.exception);
129         }
130     }
131 
132     public void unbind(SocketAddress address) {
133         if (address == null)
134             throw new NullPointerException("address");
135 
136         CancellationRequest request = new CancellationRequest(address);
137         synchronized (this) {
138             try {
139                 startupWorker();
140             } catch (IOException e) {
141                 // IOException is thrown only when Worker thread is not
142                 // running and failed to open a selector.  We simply throw
143                 // IllegalArgumentException here because we can simply
144                 // conclude that nothing is bound to the selector.
145                 throw new IllegalArgumentException("Address not bound: "
146                         + address);
147             }
148 
149             synchronized (cancelQueue) {
150                 cancelQueue.push(request);
151             }
152             selector.wakeup();
153         }
154 
155         synchronized (request) {
156             while (!request.done) {
157                 try {
158                     request.wait();
159                 } catch (InterruptedException e) {
160                 }
161             }
162         }
163 
164         if (request.exception != null) {
165             throw new RuntimeException("Failed to unbind", request.exception);
166         }
167     }
168 
169     public void unbindAll() {
170         List addresses;
171         synchronized (channels) {
172             addresses = new ArrayList(channels.keySet());
173         }
174 
175         for (Iterator i = addresses.iterator(); i.hasNext();) {
176             unbind((SocketAddress) i.next());
177         }
178     }
179 
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 = getSelector();
190         DatagramChannel ch = (DatagramChannel) 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     public IoServiceListenerSupport getListeners() {
249         return super.getListeners();
250     }
251 
252     private void buildFilterChain(RegistrationRequest req, IoSession session)
253             throws Exception {
254         this.getFilterChainBuilder().buildFilterChain(session.getFilterChain());
255         req.config.getFilterChainBuilder().buildFilterChain(
256                 session.getFilterChain());
257         req.config.getThreadModel().buildFilterChain(session.getFilterChain());
258     }
259 
260     public IoServiceConfig getDefaultConfig() {
261         return defaultConfig;
262     }
263 
264     /**
265      * Sets the config this acceptor will use by default.
266      * 
267      * @param defaultConfig the default config.
268      * @throws NullPointerException if the specified value is <code>null</code>.
269      */
270     public void setDefaultConfig(DatagramAcceptorConfig defaultConfig) {
271         if (defaultConfig == null) {
272             throw new NullPointerException("defaultConfig");
273         }
274         this.defaultConfig = defaultConfig;
275     }
276     
277     private synchronized Selector getSelector() {
278         return this.selector;
279     }
280 
281     private synchronized void startupWorker() throws IOException {
282         if (worker == null) {
283             selector = Selector.open();
284             worker = new Worker();
285             executor.execute(new NamePreservingRunnable(worker));
286         }
287     }
288 
289     public void flushSession(DatagramSessionImpl session) {
290         scheduleFlush(session);
291         Selector selector = getSelector();
292         if (selector != null) {
293             selector.wakeup();
294         }
295     }
296 
297     public void closeSession(DatagramSessionImpl session) {
298     }
299 
300     private void scheduleFlush(DatagramSessionImpl session) {
301         synchronized (flushingSessions) {
302             flushingSessions.push(session);
303         }
304     }
305 
306     private class Worker implements Runnable {
307         public void run() {
308             Thread.currentThread().setName("DatagramAcceptor-" + id);
309 
310             Selector selector = DatagramAcceptorDelegate.this.getSelector();
311             for (;;) {
312                 try {
313                     int nKeys = selector.select();
314 
315                     registerNew();
316 
317                     if (nKeys > 0) {
318                         processReadySessions(selector.selectedKeys());
319                     }
320 
321                     flushSessions();
322                     cancelKeys();
323 
324                     if (selector.keys().isEmpty()) {
325                         synchronized (DatagramAcceptorDelegate.this) {
326                             if (selector.keys().isEmpty()
327                                     && registerQueue.isEmpty()
328                                     && cancelQueue.isEmpty()) {
329                                 worker = null;
330                                 try {
331                                     selector.close();
332                                 } catch (IOException e) {
333                                     ExceptionMonitor.getInstance()
334                                             .exceptionCaught(e);
335                                 } finally {
336                                     DatagramAcceptorDelegate.this.selector = null;
337                                 }
338                                 break;
339                             }
340                         }
341                     }
342                 } catch (IOException e) {
343                     ExceptionMonitor.getInstance().exceptionCaught(e);
344 
345                     try {
346                         Thread.sleep(1000);
347                     } catch (InterruptedException e1) {
348                     }
349                 }
350             }
351         }
352     }
353 
354     private void processReadySessions(Set keys) {
355         Iterator it = keys.iterator();
356         while (it.hasNext()) {
357             SelectionKey key = (SelectionKey) it.next();
358             it.remove();
359 
360             DatagramChannel ch = (DatagramChannel) key.channel();
361 
362             RegistrationRequest req = (RegistrationRequest) key.attachment();
363             try {
364                 if (key.isReadable()) {
365                     readSession(ch, req);
366                 }
367 
368                 if (key.isWritable()) {
369                     for (Iterator i = getManagedSessions(req.address)
370                             .iterator(); i.hasNext();) {
371                         scheduleFlush((DatagramSessionImpl) i.next());
372                     }
373                 }
374             } catch (Throwable t) {
375                 ExceptionMonitor.getInstance().exceptionCaught(t);
376             }
377         }
378     }
379 
380     private void readSession(DatagramChannel channel, RegistrationRequest req)
381             throws Exception {
382         ByteBuffer readBuf = ByteBuffer
383                 .allocate(((DatagramSessionConfig) req.config
384                         .getSessionConfig()).getReceiveBufferSize());
385         try {
386             SocketAddress remoteAddress = channel.receive(readBuf.buf());
387             if (remoteAddress != null) {
388                 DatagramSessionImpl session = (DatagramSessionImpl) newSession(
389                         remoteAddress, req.address);
390 
391                 readBuf.flip();
392 
393                 ByteBuffer newBuf = ByteBuffer.allocate(readBuf.limit());
394                 newBuf.put(readBuf);
395                 newBuf.flip();
396 
397                 session.increaseReadBytes(newBuf.remaining());
398                 session.getFilterChain().fireMessageReceived(session, newBuf);
399             }
400         } finally {
401             readBuf.release();
402         }
403     }
404 
405     private void flushSessions() {
406         if (flushingSessions.size() == 0)
407             return;
408 
409         for (;;) {
410             DatagramSessionImpl session;
411 
412             synchronized (flushingSessions) {
413                 session = (DatagramSessionImpl) flushingSessions.pop();
414             }
415 
416             if (session == null)
417                 break;
418 
419             try {
420                 flush(session);
421             } catch (IOException e) {
422                 session.getFilterChain().fireExceptionCaught(session, e);
423             }
424         }
425     }
426 
427     private void flush(DatagramSessionImpl session) throws IOException {
428         DatagramChannel ch = session.getChannel();
429 
430         Queue writeRequestQueue = session.getWriteRequestQueue();
431 
432         WriteRequest req;
433         for (;;) {
434             synchronized (writeRequestQueue) {
435                 req = (WriteRequest) writeRequestQueue.first();
436             }
437 
438             if (req == null)
439                 break;
440 
441             ByteBuffer buf = (ByteBuffer) req.getMessage();
442             if (buf.remaining() == 0) {
443                 // pop and fire event
444                 synchronized (writeRequestQueue) {
445                     writeRequestQueue.pop();
446                 }
447 
448                 session.increaseWrittenMessages();
449                 buf.reset();
450                 ((DatagramFilterChain) session.getFilterChain())
451                         .fireMessageSent(session, req);
452                 continue;
453             }
454 
455             SelectionKey key = session.getSelectionKey();
456             if (key == null) {
457                 scheduleFlush(session);
458                 break;
459             }
460             if (!key.isValid()) {
461                 continue;
462             }
463 
464             SocketAddress destination = req.getDestination();
465             if (destination == null) {
466                 destination = session.getRemoteAddress();
467             }
468 
469             int writtenBytes = ch.send(buf.buf(), destination);
470 
471             if (writtenBytes == 0) {
472                 // Kernel buffer is full
473                 key.interestOps(key.interestOps() | SelectionKey.OP_WRITE);
474             } else if (writtenBytes > 0) {
475                 key.interestOps(key.interestOps() & (~SelectionKey.OP_WRITE));
476 
477                 // pop and fire event
478                 synchronized (writeRequestQueue) {
479                     writeRequestQueue.pop();
480                 }
481 
482                 session.increaseWrittenBytes(writtenBytes);
483                 session.increaseWrittenMessages();
484                 buf.reset();
485                 session.getFilterChain().fireMessageSent(session, req);
486             }
487         }
488     }
489 
490     private void registerNew() {
491         if (registerQueue.isEmpty())
492             return;
493 
494         Selector selector = getSelector();
495         for (;;) {
496             RegistrationRequest req;
497             synchronized (registerQueue) {
498                 req = (RegistrationRequest) registerQueue.pop();
499             }
500 
501             if (req == null)
502                 break;
503 
504             DatagramChannel ch = null;
505             try {
506                 ch = DatagramChannel.open();
507                 DatagramSessionConfig cfg;
508                 if (req.config.getSessionConfig() instanceof DatagramSessionConfig) {
509                     cfg = (DatagramSessionConfig) req.config.getSessionConfig();
510                 } else {
511                     cfg = (DatagramSessionConfig) getDefaultConfig()
512                             .getSessionConfig();
513                 }
514 
515                 ch.socket().setReuseAddress(cfg.isReuseAddress());
516                 ch.socket().setBroadcast(cfg.isBroadcast());
517                 ch.socket().setReceiveBufferSize(cfg.getReceiveBufferSize());
518                 ch.socket().setSendBufferSize(cfg.getSendBufferSize());
519 
520                 if (ch.socket().getTrafficClass() != cfg.getTrafficClass()) {
521                     ch.socket().setTrafficClass(cfg.getTrafficClass());
522                 }
523 
524                 ch.configureBlocking(false);
525                 ch.socket().bind(req.address);
526                 if (req.address == null || req.address.getPort() == 0) {
527                     req.address = (InetSocketAddress) ch.socket()
528                             .getLocalSocketAddress();
529                 }
530                 ch.register(selector, SelectionKey.OP_READ, req);
531                 synchronized (channels) {
532                     channels.put(req.address, ch);
533                 }
534 
535                 getListeners().fireServiceActivated(this, req.address,
536                         req.handler, req.config);
537             } catch (Throwable t) {
538                 req.exception = t;
539             } finally {
540                 synchronized (req) {
541                     req.done = true;
542                     req.notify();
543                 }
544 
545                 if (ch != null && req.exception != null) {
546                     try {
547                         ch.disconnect();
548                         ch.close();
549                     } catch (Throwable e) {
550                         ExceptionMonitor.getInstance().exceptionCaught(e);
551                     }
552                 }
553             }
554         }
555     }
556 
557     private void cancelKeys() {
558         if (cancelQueue.isEmpty())
559             return;
560 
561         Selector selector = getSelector();
562         for (;;) {
563             CancellationRequest request;
564             synchronized (cancelQueue) {
565                 request = (CancellationRequest) cancelQueue.pop();
566             }
567 
568             if (request == null) {
569                 break;
570             }
571 
572             DatagramChannel ch;
573             synchronized (channels) {
574                 ch = (DatagramChannel) channels.remove(request.address);
575             }
576 
577             // close the channel
578             try {
579                 if (ch == null) {
580                     request.exception = new IllegalArgumentException(
581                             "Address not bound: " + request.address);
582                 } else {
583                     SelectionKey key = ch.keyFor(selector);
584                     request.registrationRequest = (RegistrationRequest) key
585                             .attachment();
586                     key.cancel();
587                     selector.wakeup(); // wake up again to trigger thread death
588                     ch.disconnect();
589                     ch.close();
590                 }
591             } catch (Throwable t) {
592                 ExceptionMonitor.getInstance().exceptionCaught(t);
593             } finally {
594                 synchronized (request) {
595                     request.done = true;
596                     request.notify();
597                 }
598 
599                 if (request.exception == null) {
600                     getListeners().fireServiceDeactivated(this,
601                             request.address,
602                             request.registrationRequest.handler,
603                             request.registrationRequest.config);
604                 }
605             }
606         }
607     }
608 
609     public void updateTrafficMask(DatagramSessionImpl session) {
610         // There's no point in changing the traffic mask for sessions originating
611         // from this acceptor since new sessions are created every time data is
612         // received.
613     }
614 
615     private static class RegistrationRequest {
616         private InetSocketAddress address;
617 
618         private final IoHandler handler;
619 
620         private final IoServiceConfig config;
621 
622         private Throwable exception;
623 
624         private boolean done;
625 
626         private RegistrationRequest(SocketAddress address, IoHandler handler,
627                 IoServiceConfig config) {
628             this.address = (InetSocketAddress) address;
629             this.handler = handler;
630             this.config = config;
631         }
632     }
633 
634     private static class CancellationRequest {
635         private final SocketAddress address;
636 
637         private boolean done;
638 
639         private RegistrationRequest registrationRequest;
640 
641         private RuntimeException exception;
642 
643         private CancellationRequest(SocketAddress address) {
644             this.address = address;
645         }
646     }
647 }