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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: 555855 $, $Date: 2007-07-13 12:19:00 +0900 (금, 13  7월 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         }
115         selector.wakeup();
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         }
153         selector.wakeup();
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 = this.selector;
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 void startupWorker() throws IOException {
278         if (worker == null) {
279             selector = Selector.open();
280             worker = new Worker();
281             executor.execute(new NamePreservingRunnable(worker));
282         }
283     }
284 
285     public void flushSession(DatagramSessionImpl session) {
286         scheduleFlush(session);
287         Selector selector = this.selector;
288         if (selector != null) {
289             selector.wakeup();
290         }
291     }
292 
293     public void closeSession(DatagramSessionImpl session) {
294     }
295 
296     private void scheduleFlush(DatagramSessionImpl session) {
297         synchronized (flushingSessions) {
298             flushingSessions.push(session);
299         }
300     }
301 
302     private class Worker implements Runnable {
303         public void run() {
304             Thread.currentThread().setName("DatagramAcceptor-" + id);
305 
306             for (;;) {
307                 try {
308                     int nKeys = selector.select();
309 
310                     registerNew();
311 
312                     if (nKeys > 0) {
313                         processReadySessions(selector.selectedKeys());
314                     }
315 
316                     flushSessions();
317                     cancelKeys();
318 
319                     if (selector.keys().isEmpty()) {
320                         synchronized (DatagramAcceptorDelegate.this) {
321                             if (selector.keys().isEmpty()
322                                     && registerQueue.isEmpty()
323                                     && cancelQueue.isEmpty()) {
324                                 worker = null;
325                                 try {
326                                     selector.close();
327                                 } catch (IOException e) {
328                                     ExceptionMonitor.getInstance()
329                                             .exceptionCaught(e);
330                                 } finally {
331                                     selector = null;
332                                 }
333                                 break;
334                             }
335                         }
336                     }
337                 } catch (IOException e) {
338                     ExceptionMonitor.getInstance().exceptionCaught(e);
339 
340                     try {
341                         Thread.sleep(1000);
342                     } catch (InterruptedException e1) {
343                     }
344                 }
345             }
346         }
347     }
348 
349     private void processReadySessions(Set keys) {
350         Iterator it = keys.iterator();
351         while (it.hasNext()) {
352             SelectionKey key = (SelectionKey) it.next();
353             it.remove();
354 
355             DatagramChannel ch = (DatagramChannel) key.channel();
356 
357             RegistrationRequest req = (RegistrationRequest) key.attachment();
358             try {
359                 if (key.isReadable()) {
360                     readSession(ch, req);
361                 }
362 
363                 if (key.isWritable()) {
364                     for (Iterator i = getManagedSessions(req.address)
365                             .iterator(); i.hasNext();) {
366                         scheduleFlush((DatagramSessionImpl) i.next());
367                     }
368                 }
369             } catch (Throwable t) {
370                 ExceptionMonitor.getInstance().exceptionCaught(t);
371             }
372         }
373     }
374 
375     private void readSession(DatagramChannel channel, RegistrationRequest req)
376             throws Exception {
377         ByteBuffer readBuf = ByteBuffer
378                 .allocate(((DatagramSessionConfig) req.config
379                         .getSessionConfig()).getReceiveBufferSize());
380         try {
381             SocketAddress remoteAddress = channel.receive(readBuf.buf());
382             if (remoteAddress != null) {
383                 DatagramSessionImpl session = (DatagramSessionImpl) newSession(
384                         remoteAddress, req.address);
385 
386                 readBuf.flip();
387 
388                 ByteBuffer newBuf = ByteBuffer.allocate(readBuf.limit());
389                 newBuf.put(readBuf);
390                 newBuf.flip();
391 
392                 session.increaseReadBytes(newBuf.remaining());
393                 session.getFilterChain().fireMessageReceived(session, newBuf);
394             }
395         } finally {
396             readBuf.release();
397         }
398     }
399 
400     private void flushSessions() {
401         if (flushingSessions.size() == 0)
402             return;
403 
404         for (;;) {
405             DatagramSessionImpl session;
406 
407             synchronized (flushingSessions) {
408                 session = (DatagramSessionImpl) flushingSessions.pop();
409             }
410 
411             if (session == null)
412                 break;
413 
414             try {
415                 flush(session);
416             } catch (IOException e) {
417                 session.getFilterChain().fireExceptionCaught(session, e);
418             }
419         }
420     }
421 
422     private void flush(DatagramSessionImpl session) throws IOException {
423         DatagramChannel ch = session.getChannel();
424 
425         Queue writeRequestQueue = session.getWriteRequestQueue();
426 
427         WriteRequest req;
428         for (;;) {
429             synchronized (writeRequestQueue) {
430                 req = (WriteRequest) writeRequestQueue.first();
431             }
432 
433             if (req == null)
434                 break;
435 
436             ByteBuffer buf = (ByteBuffer) req.getMessage();
437             if (buf.remaining() == 0) {
438                 // pop and fire event
439                 synchronized (writeRequestQueue) {
440                     writeRequestQueue.pop();
441                 }
442 
443                 session.increaseWrittenMessages();
444                 buf.reset();
445                 ((DatagramFilterChain) session.getFilterChain())
446                         .fireMessageSent(session, req);
447                 continue;
448             }
449 
450             SelectionKey key = session.getSelectionKey();
451             if (key == null) {
452                 scheduleFlush(session);
453                 break;
454             }
455             if (!key.isValid()) {
456                 continue;
457             }
458 
459             SocketAddress destination = req.getDestination();
460             if (destination == null) {
461                 destination = session.getRemoteAddress();
462             }
463 
464             int writtenBytes = ch.send(buf.buf(), destination);
465 
466             if (writtenBytes == 0) {
467                 // Kernel buffer is full
468                 key.interestOps(key.interestOps() | SelectionKey.OP_WRITE);
469             } else if (writtenBytes > 0) {
470                 key.interestOps(key.interestOps() & (~SelectionKey.OP_WRITE));
471 
472                 // pop and fire event
473                 synchronized (writeRequestQueue) {
474                     writeRequestQueue.pop();
475                 }
476 
477                 session.increaseWrittenBytes(writtenBytes);
478                 session.increaseWrittenMessages();
479                 buf.reset();
480                 session.getFilterChain().fireMessageSent(session, req);
481             }
482         }
483     }
484 
485     private void registerNew() {
486         if (registerQueue.isEmpty())
487             return;
488 
489         for (;;) {
490             RegistrationRequest req;
491             synchronized (registerQueue) {
492                 req = (RegistrationRequest) registerQueue.pop();
493             }
494 
495             if (req == null)
496                 break;
497 
498             DatagramChannel ch = null;
499             try {
500                 ch = DatagramChannel.open();
501                 DatagramSessionConfig cfg;
502                 if (req.config.getSessionConfig() instanceof DatagramSessionConfig) {
503                     cfg = (DatagramSessionConfig) req.config.getSessionConfig();
504                 } else {
505                     cfg = (DatagramSessionConfig) getDefaultConfig()
506                             .getSessionConfig();
507                 }
508 
509                 ch.socket().setReuseAddress(cfg.isReuseAddress());
510                 ch.socket().setBroadcast(cfg.isBroadcast());
511                 ch.socket().setReceiveBufferSize(cfg.getReceiveBufferSize());
512                 ch.socket().setSendBufferSize(cfg.getSendBufferSize());
513 
514                 if (ch.socket().getTrafficClass() != cfg.getTrafficClass()) {
515                     ch.socket().setTrafficClass(cfg.getTrafficClass());
516                 }
517 
518                 ch.configureBlocking(false);
519                 ch.socket().bind(req.address);
520                 if (req.address == null || req.address.getPort() == 0) {
521                     req.address = (InetSocketAddress) ch.socket()
522                             .getLocalSocketAddress();
523                 }
524                 ch.register(selector, SelectionKey.OP_READ, req);
525                 synchronized (channels) {
526                     channels.put(req.address, ch);
527                 }
528 
529                 getListeners().fireServiceActivated(this, req.address,
530                         req.handler, req.config);
531             } catch (Throwable t) {
532                 req.exception = t;
533             } finally {
534                 synchronized (req) {
535                     req.done = true;
536                     req.notify();
537                 }
538 
539                 if (ch != null && req.exception != null) {
540                     try {
541                         ch.disconnect();
542                         ch.close();
543                     } catch (Throwable e) {
544                         ExceptionMonitor.getInstance().exceptionCaught(e);
545                     }
546                 }
547             }
548         }
549     }
550 
551     private void cancelKeys() {
552         if (cancelQueue.isEmpty())
553             return;
554 
555         for (;;) {
556             CancellationRequest request;
557             synchronized (cancelQueue) {
558                 request = (CancellationRequest) cancelQueue.pop();
559             }
560 
561             if (request == null) {
562                 break;
563             }
564 
565             DatagramChannel ch;
566             synchronized (channels) {
567                 ch = (DatagramChannel) channels.remove(request.address);
568             }
569 
570             // close the channel
571             try {
572                 if (ch == null) {
573                     request.exception = new IllegalArgumentException(
574                             "Address not bound: " + request.address);
575                 } else {
576                     SelectionKey key = ch.keyFor(selector);
577                     request.registrationRequest = (RegistrationRequest) key
578                             .attachment();
579                     key.cancel();
580                     selector.wakeup(); // wake up again to trigger thread death
581                     ch.disconnect();
582                     ch.close();
583                 }
584             } catch (Throwable t) {
585                 ExceptionMonitor.getInstance().exceptionCaught(t);
586             } finally {
587                 synchronized (request) {
588                     request.done = true;
589                     request.notify();
590                 }
591 
592                 if (request.exception == null) {
593                     getListeners().fireServiceDeactivated(this,
594                             request.address,
595                             request.registrationRequest.handler,
596                             request.registrationRequest.config);
597                 }
598             }
599         }
600     }
601 
602     public void updateTrafficMask(DatagramSessionImpl session) {
603         // There's no point in changing the traffic mask for sessions originating
604         // from this acceptor since new sessions are created every time data is
605         // received.
606     }
607 
608     private static class RegistrationRequest {
609         private InetSocketAddress address;
610 
611         private final IoHandler handler;
612 
613         private final IoServiceConfig config;
614 
615         private Throwable exception;
616 
617         private boolean done;
618 
619         private RegistrationRequest(SocketAddress address, IoHandler handler,
620                 IoServiceConfig config) {
621             this.address = (InetSocketAddress) address;
622             this.handler = handler;
623             this.config = config;
624         }
625     }
626 
627     private static class CancellationRequest {
628         private final SocketAddress address;
629 
630         private boolean done;
631 
632         private RegistrationRequest registrationRequest;
633 
634         private RuntimeException exception;
635 
636         private CancellationRequest(SocketAddress address) {
637             this.address = address;
638         }
639     }
640 }