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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.commons.net.tftp;
19  
20  import java.io.IOException;
21  import java.io.InputStream;
22  import java.io.InterruptedIOException;
23  import java.io.OutputStream;
24  import java.net.InetAddress;
25  import java.net.SocketException;
26  import java.net.UnknownHostException;
27  import org.apache.commons.net.io.FromNetASCIIOutputStream;
28  import org.apache.commons.net.io.ToNetASCIIInputStream;
29  
30  /***
31   * The TFTPClient class encapsulates all the aspects of the TFTP protocol
32   * necessary to receive and send files through TFTP.  It is derived from
33   * the {@link org.apache.commons.net.tftp.TFTP} because
34   * it is more convenient than using aggregation, and as a result exposes
35   * the same set of methods to allow you to deal with the TFTP protocol
36   * directly.  However, almost every user should only be concerend with the
37   * the {@link org.apache.commons.net.DatagramSocketClient#open  open() },
38   * {@link org.apache.commons.net.DatagramSocketClient#close  close() },
39   * {@link #sendFile  sendFile() }, and
40   * {@link #receiveFile  receiveFile() } methods.  Additionally, the
41   * {@link #setMaxTimeouts  setMaxTimeouts() } and
42   * {@link org.apache.commons.net.DatagramSocketClient#setDefaultTimeout setDefaultTimeout() }
43   *  methods may be of importance for performance
44   * tuning.
45   * <p>
46   * Details regarding the TFTP protocol and the format of TFTP packets can
47   * be found in RFC 783.  But the point of these classes is to keep you
48   * from having to worry about the internals.
49   * <p>
50   * <p>
51   * @author Daniel F. Savarese
52   * @see TFTP
53   * @see TFTPPacket
54   * @see TFTPPacketException
55   ***/
56  
57  public class TFTPClient extends TFTP
58  {
59      /***
60       * The default number of times a receive attempt is allowed to timeout
61       * before ending attempts to retry the receive and failing.  The default
62       * is 5 timeouts.
63       ***/
64      public static final int DEFAULT_MAX_TIMEOUTS = 5;
65  
66      /*** The maximum number of timeouts allowed before failing. ***/
67      private int __maxTimeouts;
68  
69      /***
70       * Creates a TFTPClient instance with a default timeout of DEFAULT_TIMEOUT,
71       * maximum timeouts value of DEFAULT_MAX_TIMEOUTS, a null socket,
72       * and buffered operations disabled.
73       ***/
74      public TFTPClient()
75      {
76          __maxTimeouts = DEFAULT_MAX_TIMEOUTS;
77      }
78  
79      /***
80       * Sets the maximum number of times a receive attempt is allowed to
81       * timeout during a receiveFile() or sendFile() operation before ending
82       * attempts to retry the receive and failing.
83       * The default is DEFAULT_MAX_TIMEOUTS.
84       * <p>
85       * @param numTimeouts  The maximum number of timeouts to allow.  Values
86       *        less than 1 should not be used, but if they are, they are
87       *        treated as 1.
88       ***/
89      public void setMaxTimeouts(int numTimeouts)
90      {
91          if (numTimeouts < 1)
92              __maxTimeouts = 1;
93          else
94              __maxTimeouts = numTimeouts;
95      }
96  
97      /***
98       * Returns the maximum number of times a receive attempt is allowed to
99       * timeout before ending attempts to retry the receive and failing.
100      * <p>
101      * @return The maximum number of timeouts allowed.
102      ***/
103     public int getMaxTimeouts()
104     {
105         return __maxTimeouts;
106     }
107 
108 
109     /***
110      * Requests a named file from a remote host, writes the
111      * file to an OutputStream, closes the connection, and returns the number
112      * of bytes read.  A local UDP socket must first be created by
113      * {@link org.apache.commons.net.DatagramSocketClient#open open()} before
114      * invoking this method.  This method will not close the OutputStream
115      * containing the file; you must close it after the method invocation.
116      * <p>
117      * @param filename  The name of the file to receive.
118      * @param mode   The TFTP mode of the transfer (one of the MODE constants).
119      * @param output The OutputStream to which the file should be written.
120      * @param host   The remote host serving the file.
121      * @param port   The port number of the remote TFTP server.
122      * @exception IOException If an I/O error occurs.  The nature of the
123      *            error will be reported in the message.
124      ***/
125     public int receiveFile(String filename, int mode, OutputStream output,
126                            InetAddress host, int port) throws IOException
127     {
128         int bytesRead, timeouts, lastBlock, block, hostPort, dataLength;
129         TFTPPacket sent, received = null;
130         TFTPErrorPacket error;
131         TFTPDataPacket data;
132         TFTPAckPacket ack = new TFTPAckPacket(host, port, 0);
133 
134         beginBufferedOps();
135 
136         dataLength = lastBlock = hostPort = bytesRead = 0;
137         block = 1;
138 
139         if (mode == TFTP.ASCII_MODE)
140             output = new FromNetASCIIOutputStream(output);
141 
142         sent =
143             new TFTPReadRequestPacket(host, port, filename, mode);
144 
145 _sendPacket:
146         do
147         {
148             bufferedSend(sent);
149 
150 _receivePacket:
151             while (true)
152             {
153                 timeouts = 0;
154                 while (timeouts < __maxTimeouts)
155                 {
156                     try
157                     {
158                         received = bufferedReceive();
159                         break;
160                     }
161                     catch (SocketException e)
162                     {
163                         if (++timeouts >= __maxTimeouts)
164                         {
165                             endBufferedOps();
166                             throw new IOException("Connection timed out.");
167                         }
168                         continue;
169                     }
170                     catch (InterruptedIOException e)
171                     {
172                         if (++timeouts >= __maxTimeouts)
173                         {
174                             endBufferedOps();
175                             throw new IOException("Connection timed out.");
176                         }
177                         continue;
178                     }
179                     catch (TFTPPacketException e)
180                     {
181                         endBufferedOps();
182                         throw new IOException("Bad packet: " + e.getMessage());
183                     }
184                 }
185 
186                 // The first time we receive we get the port number and
187         // answering host address (for hosts with multiple IPs)
188                 if (lastBlock == 0)
189                 {
190                     hostPort = received.getPort();
191                     ack.setPort(hostPort);
192                     if(!host.equals(received.getAddress()))
193                     {
194                         host = received.getAddress();
195                         ack.setAddress(host);
196                         sent.setAddress(host);
197                     }
198                 }
199 
200                 // Comply with RFC 783 indication that an error acknowledgement
201                 // should be sent to originator if unexpected TID or host.
202                 if (host.equals(received.getAddress()) &&
203                         received.getPort() == hostPort)
204                 {
205 
206                     switch (received.getType())
207                     {
208                     case TFTPPacket.ERROR:
209                         error = (TFTPErrorPacket)received;
210                         endBufferedOps();
211                         throw new IOException("Error code " + error.getError() +
212                                               " received: " + error.getMessage());
213                     case TFTPPacket.DATA:
214                         data = (TFTPDataPacket)received;
215                         dataLength = data.getDataLength();
216 
217                         lastBlock = data.getBlockNumber();
218 
219                         if (lastBlock == block)
220                         {
221                             try
222                             {
223                                 output.write(data.getData(), data.getDataOffset(),
224                                              dataLength);
225                             }
226                             catch (IOException e)
227                             {
228                                 error = new TFTPErrorPacket(host, hostPort,
229                                                             TFTPErrorPacket.OUT_OF_SPACE,
230                                                             "File write failed.");
231                                 bufferedSend(error);
232                                 endBufferedOps();
233                                 throw e;
234                             }
235                             ++block;
236                             if (block > 65535)
237                             {
238                                 // wrap the block number
239                                 block = 0;
240                             }
241                             
242                             break _receivePacket;
243                         }
244                         else
245                         {
246                             discardPackets();
247 
248                             if (lastBlock == (block == 0 ? 65535 : (block - 1)))
249                                 continue _sendPacket;  // Resend last acknowledgement.
250 
251                             continue _receivePacket; // Start fetching packets again.
252                         }
253                         //break;
254 
255                     default:
256                         endBufferedOps();
257                         throw new IOException("Received unexpected packet type.");
258                     }
259                 }
260                 else
261                 {
262                     error = new TFTPErrorPacket(received.getAddress(),
263                                                 received.getPort(),
264                                                 TFTPErrorPacket.UNKNOWN_TID,
265                                                 "Unexpected host or port.");
266                     bufferedSend(error);
267                     continue _sendPacket;
268                 }
269 
270                 // We should never get here, but this is a safety to avoid
271                 // infinite loop.  If only Java had the goto statement.
272                 //break;
273             }
274 
275             ack.setBlockNumber(lastBlock);
276             sent = ack;
277             bytesRead += dataLength;
278         } // First data packet less than 512 bytes signals end of stream.
279 
280         while (dataLength == TFTPPacket.SEGMENT_SIZE);
281 
282         bufferedSend(sent);
283         endBufferedOps();
284 
285         return bytesRead;
286     }
287 
288 
289     /***
290      * Requests a named file from a remote host, writes the
291      * file to an OutputStream, closes the connection, and returns the number
292      * of bytes read.  A local UDP socket must first be created by
293      * {@link org.apache.commons.net.DatagramSocketClient#open open()} before
294      * invoking this method.  This method will not close the OutputStream
295      * containing the file; you must close it after the method invocation.
296      * <p>
297      * @param filename The name of the file to receive.
298      * @param mode     The TFTP mode of the transfer (one of the MODE constants).
299      * @param output   The OutputStream to which the file should be written.
300      * @param hostname The name of the remote host serving the file.
301      * @param port     The port number of the remote TFTP server.
302      * @exception IOException If an I/O error occurs.  The nature of the
303      *            error will be reported in the message.
304      * @exception UnknownHostException  If the hostname cannot be resolved.
305      ***/
306     public int receiveFile(String filename, int mode, OutputStream output,
307                            String hostname, int port)
308     throws UnknownHostException, IOException
309     {
310         return receiveFile(filename, mode, output, InetAddress.getByName(hostname),
311                            port);
312     }
313 
314 
315     /***
316      * Same as calling receiveFile(filename, mode, output, host, TFTP.DEFAULT_PORT).
317      *
318      * @param filename The name of the file to receive.
319      * @param mode     The TFTP mode of the transfer (one of the MODE constants).
320      * @param output   The OutputStream to which the file should be written.
321      * @param host     The remote host serving the file.
322      * @exception IOException If an I/O error occurs.  The nature of the
323      *            error will be reported in the message.
324      ***/
325     public int receiveFile(String filename, int mode, OutputStream output,
326                            InetAddress host)
327     throws IOException
328     {
329         return receiveFile(filename, mode, output, host, DEFAULT_PORT);
330     }
331 
332     /***
333      * Same as calling receiveFile(filename, mode, output, hostname, TFTP.DEFAULT_PORT).
334      *
335      * @param filename The name of the file to receive.
336      * @param mode     The TFTP mode of the transfer (one of the MODE constants).
337      * @param output   The OutputStream to which the file should be written.
338      * @param hostname The name of the remote host serving the file.
339      * @exception IOException If an I/O error occurs.  The nature of the
340      *            error will be reported in the message.
341      * @exception UnknownHostException  If the hostname cannot be resolved.
342      ***/
343     public int receiveFile(String filename, int mode, OutputStream output,
344                            String hostname)
345     throws UnknownHostException, IOException
346     {
347         return receiveFile(filename, mode, output, InetAddress.getByName(hostname),
348                            DEFAULT_PORT);
349     }
350 
351 
352     /***
353      * Requests to send a file to a remote host, reads the file from an
354      * InputStream, sends the file to the remote host, and closes the
355      * connection.  A local UDP socket must first be created by
356      * {@link org.apache.commons.net.DatagramSocketClient#open open()} before
357      * invoking this method.  This method will not close the InputStream
358      * containing the file; you must close it after the method invocation.
359      * <p>
360      * @param filename The name the remote server should use when creating
361      *        the file on its file system.
362      * @param mode     The TFTP mode of the transfer (one of the MODE constants).
363      * @param host     The remote host receiving the file.
364      * @param port     The port number of the remote TFTP server.
365      * @exception IOException If an I/O error occurs.  The nature of the
366      *            error will be reported in the message.
367      ***/
368     public void sendFile(String filename, int mode, InputStream input,
369                          InetAddress host, int port) throws IOException
370     {
371         int bytesRead, timeouts, lastBlock, block, hostPort, dataLength, offset, totalThisPacket;
372         TFTPPacket sent, received = null;
373         TFTPErrorPacket error;
374         TFTPDataPacket data =
375             new TFTPDataPacket(host, port, 0, _sendBuffer, 4, 0);
376         TFTPAckPacket ack;
377 
378         boolean justStarted = true;
379         
380         beginBufferedOps();
381 
382         dataLength = lastBlock = hostPort = bytesRead = totalThisPacket = 0;
383         block = 0;
384         boolean lastAckWait = false;
385 
386         if (mode == TFTP.ASCII_MODE)
387             input = new ToNetASCIIInputStream(input);
388 
389         sent =
390             new TFTPWriteRequestPacket(host, port, filename, mode);
391 
392 _sendPacket:
393         do
394         {
395             // first time: block is 0, lastBlock is 0, send a request packet.
396             // subsequent: block is integer starting at 1, send data packet.
397             bufferedSend(sent);
398             
399             // this is trying to receive an ACK
400 _receivePacket:
401             while (true)
402             {
403                 
404 
405                 timeouts = 0;
406                 while (timeouts < __maxTimeouts)
407                 {
408                     try
409                     {
410                         received = bufferedReceive();
411                         break;
412                     }
413                     catch (SocketException e)
414                     {
415                         if (++timeouts >= __maxTimeouts)
416                         {
417                             endBufferedOps();
418                             throw new IOException("Connection timed out.");
419                         }
420                         continue;
421                     }
422                     catch (InterruptedIOException e)
423                     {
424                         if (++timeouts >= __maxTimeouts)
425                         {
426                             endBufferedOps();
427                             throw new IOException("Connection timed out.");
428                         }
429                         continue;
430                     }
431                     catch (TFTPPacketException e)
432                     {
433                         endBufferedOps();
434                         throw new IOException("Bad packet: " + e.getMessage());
435                     }
436                 } // end of while loop over tries to receive
437 
438                 // The first time we receive we get the port number and
439         // answering host address (for hosts with multiple IPs)
440                 if (justStarted)
441                 {
442                     justStarted = false;
443                     hostPort = received.getPort();
444                     data.setPort(hostPort);
445                     if(!host.equals(received.getAddress()))
446                     {
447                         host = received.getAddress();
448                         data.setAddress(host);
449                         sent.setAddress(host);
450                     }
451                 }
452 
453                 // Comply with RFC 783 indication that an error acknowledgement
454                 // should be sent to originator if unexpected TID or host.
455                 if (host.equals(received.getAddress()) &&
456                         received.getPort() == hostPort)
457                 {
458 
459                     switch (received.getType())
460                     {
461                     case TFTPPacket.ERROR:
462                         error = (TFTPErrorPacket)received;
463                         endBufferedOps();
464                         throw new IOException("Error code " + error.getError() +
465                                               " received: " + error.getMessage());
466                     case TFTPPacket.ACKNOWLEDGEMENT:
467                         ack = (TFTPAckPacket)received;
468 
469                         lastBlock = ack.getBlockNumber();
470 
471                         if (lastBlock == block)
472                         {
473                             ++block;
474                             if (block > 65535)
475                             {
476                                 // wrap the block number
477                                 block = 0;
478                             }
479                             if (lastAckWait) {
480                                 
481                               break _sendPacket;
482                             }
483                             else {
484                               break _receivePacket;
485                             }
486                         }
487                         else
488                         {
489                             discardPackets();
490 
491                             if (lastBlock == (block == 0 ? 65535 : (block - 1)))
492                                 continue _sendPacket;  // Resend last acknowledgement.
493 
494                             continue _receivePacket; // Start fetching packets again.
495                         }
496                         //break;
497 
498                     default:
499                         endBufferedOps();
500                         throw new IOException("Received unexpected packet type.");
501                     }
502                 }
503                 else
504                 {
505                     error = new TFTPErrorPacket(received.getAddress(),
506                                                 received.getPort(),
507                                                 TFTPErrorPacket.UNKNOWN_TID,
508                                                 "Unexpected host or port.");
509                     bufferedSend(error);
510                     continue _sendPacket;
511                 }
512 
513                 // We should never get here, but this is a safety to avoid
514                 // infinite loop.  If only Java had the goto statement.
515                 //break;
516             }
517 
518             // OK, we have just gotten ACK about the last data we sent. Make another
519             // and send it            
520 
521             dataLength = TFTPPacket.SEGMENT_SIZE;
522             offset = 4;
523             totalThisPacket = 0;
524             while (dataLength > 0 &&
525                     (bytesRead = input.read(_sendBuffer, offset, dataLength)) > 0)
526             {
527                 offset += bytesRead;
528                 dataLength -= bytesRead;
529                 totalThisPacket += bytesRead;
530             }
531 
532             if( totalThisPacket < TFTPPacket.SEGMENT_SIZE ) {
533                 /* this will be our last packet -- send, wait for ack, stop */
534                 lastAckWait = true;
535             }
536             data.setBlockNumber(block);
537             data.setData(_sendBuffer, 4, totalThisPacket);
538             sent = data;
539         }
540         while ( totalThisPacket > 0 || lastAckWait );
541         // Note: this was looping while dataLength == 0 || lastAckWait,
542         // which was discarding the last packet if it was not full size
543         // Should send the packet. 
544         
545         endBufferedOps();
546     }
547 
548 
549     /***
550      * Requests to send a file to a remote host, reads the file from an
551      * InputStream, sends the file to the remote host, and closes the
552      * connection.  A local UDP socket must first be created by
553      * {@link org.apache.commons.net.DatagramSocketClient#open open()} before
554      * invoking this method.  This method will not close the InputStream
555      * containing the file; you must close it after the method invocation.
556      * <p>
557      * @param filename The name the remote server should use when creating
558      *        the file on its file system.
559      * @param mode     The TFTP mode of the transfer (one of the MODE constants).
560      * @param hostname The name of the remote host receiving the file.
561      * @param port     The port number of the remote TFTP server.
562      * @exception IOException If an I/O error occurs.  The nature of the
563      *            error will be reported in the message.
564      * @exception UnknownHostException  If the hostname cannot be resolved.
565      ***/
566     public void sendFile(String filename, int mode, InputStream input,
567                          String hostname, int port)
568     throws UnknownHostException, IOException
569     {
570         sendFile(filename, mode, input, InetAddress.getByName(hostname), port);
571     }
572 
573 
574     /***
575      * Same as calling sendFile(filename, mode, input, host, TFTP.DEFAULT_PORT).
576      *
577      * @param filename The name the remote server should use when creating
578      *        the file on its file system.
579      * @param mode     The TFTP mode of the transfer (one of the MODE constants).
580      * @param host     The name of the remote host receiving the file.
581      * @exception IOException If an I/O error occurs.  The nature of the
582      *            error will be reported in the message.
583      * @exception UnknownHostException  If the hostname cannot be resolved.
584      ***/
585     public void sendFile(String filename, int mode, InputStream input,
586                          InetAddress host)
587     throws IOException
588     {
589         sendFile(filename, mode, input, host, DEFAULT_PORT);
590     }
591 
592     /***
593      * Same as calling sendFile(filename, mode, input, hostname, TFTP.DEFAULT_PORT).
594      *
595      * @param filename The name the remote server should use when creating
596      *        the file on its file system.
597      * @param mode     The TFTP mode of the transfer (one of the MODE constants).
598      * @param hostname The name of the remote host receiving the file.
599      * @exception IOException If an I/O error occurs.  The nature of the
600      *            error will be reported in the message.
601      * @exception UnknownHostException  If the hostname cannot be resolved.
602      ***/
603     public void sendFile(String filename, int mode, InputStream input,
604                          String hostname)
605     throws UnknownHostException, IOException
606     {
607         sendFile(filename, mode, input, InetAddress.getByName(hostname),
608                  DEFAULT_PORT);
609     }
610 }