001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018 package org.apache.commons.net.tftp;
019
020 import java.net.DatagramPacket;
021 import java.net.InetAddress;
022
023 /***
024 * An abstract class derived from TFTPPacket definiing a TFTP Request
025 * packet type. It is subclassed by the
026 * {@link org.apache.commons.net.tftp.TFTPReadRequestPacket}
027 * and
028 * {@link org.apache.commons.net.tftp.TFTPWriteRequestPacket}
029 * classes.
030 * <p>
031 * Details regarding the TFTP protocol and the format of TFTP packets can
032 * be found in RFC 783. But the point of these classes is to keep you
033 * from having to worry about the internals. Additionally, only very
034 * few people should have to care about any of the TFTPPacket classes
035 * or derived classes. Almost all users should only be concerned with the
036 * {@link org.apache.commons.net.tftp.TFTPClient} class
037 * {@link org.apache.commons.net.tftp.TFTPClient#receiveFile receiveFile()}
038 * and
039 * {@link org.apache.commons.net.tftp.TFTPClient#sendFile sendFile()}
040 * methods.
041 * <p>
042 * <p>
043 * @see TFTPPacket
044 * @see TFTPReadRequestPacket
045 * @see TFTPWriteRequestPacket
046 * @see TFTPPacketException
047 * @see TFTP
048 ***/
049
050 public abstract class TFTPRequestPacket extends TFTPPacket
051 {
052 /***
053 * An array containing the string names of the transfer modes and indexed
054 * by the transfer mode constants.
055 ***/
056 static final String[] _modeStrings = { "netascii", "octet" };
057
058 /***
059 * A null terminated byte array representation of the ascii names of the
060 * transfer mode constants. This is convenient for creating the TFTP
061 * request packets.
062 ***/
063 private static final byte[] _modeBytes[] = {
064 { (byte)'n', (byte)'e', (byte)'t', (byte)'a', (byte)'s', (byte)'c',
065 (byte)'i', (byte)'i', 0 },
066 { (byte)'o', (byte)'c', (byte)'t', (byte)'e', (byte)'t', 0 }
067 };
068
069 /*** The transfer mode of the request. ***/
070 private final int _mode;
071
072 /*** The filename of the request. ***/
073 private final String _filename;
074
075 /***
076 * Creates a request packet of a given type to be sent to a host at a
077 * given port with a filename and transfer mode request.
078 * <p>
079 * @param destination The host to which the packet is going to be sent.
080 * @param port The port to which the packet is going to be sent.
081 * @param type The type of the request (either TFTPPacket.READ_REQUEST or
082 * TFTPPacket.WRITE_REQUEST).
083 * @param filename The requested filename.
084 * @param mode The requested transfer mode. This should be on of the TFTP
085 * class MODE constants (e.g., TFTP.NETASCII_MODE).
086 ***/
087 TFTPRequestPacket(InetAddress destination, int port,
088 int type, String filename, int mode)
089 {
090 super(type, destination, port);
091
092 _filename = filename;
093 _mode = mode;
094 }
095
096 /***
097 * Creates a request packet of a given type based on a received
098 * datagram. Assumes the datagram is at least length 4, else an
099 * ArrayIndexOutOfBoundsException may be thrown.
100 * <p>
101 * @param type The type of the request (either TFTPPacket.READ_REQUEST or
102 * TFTPPacket.WRITE_REQUEST).
103 * @param datagram The datagram containing the received request.
104 * @throws TFTPPacketException If the datagram isn't a valid TFTP
105 * request packet of the appropriate type.
106 ***/
107 TFTPRequestPacket(int type, DatagramPacket datagram)
108 throws TFTPPacketException
109 {
110 super(type, datagram.getAddress(), datagram.getPort());
111
112 byte[] data = datagram.getData();
113
114 if (getType() != data[1]) {
115 throw new TFTPPacketException("TFTP operator code does not match type.");
116 }
117
118 StringBuilder buffer = new StringBuilder();
119
120 int index = 2;
121 int length = datagram.getLength();
122
123 while (index < length && data[index] != 0)
124 {
125 buffer.append((char)data[index]);
126 ++index;
127 }
128
129 _filename = buffer.toString();
130
131 if (index >= length) {
132 throw new TFTPPacketException("Bad filename and mode format.");
133 }
134
135 buffer.setLength(0);
136 ++index; // need to advance beyond the end of string marker
137 while (index < length && data[index] != 0)
138 {
139 buffer.append((char)data[index]);
140 ++index;
141 }
142
143 String modeString = buffer.toString().toLowerCase(java.util.Locale.ENGLISH);
144 length = _modeStrings.length;
145
146 int mode = 0;
147 for (index = 0; index < length; index++)
148 {
149 if (modeString.equals(_modeStrings[index]))
150 {
151 mode = index;
152 break;
153 }
154 }
155
156 _mode = mode;
157
158 if (index >= length)
159 {
160 throw new TFTPPacketException("Unrecognized TFTP transfer mode: " + modeString);
161 // May just want to default to binary mode instead of throwing
162 // exception.
163 //_mode = TFTP.OCTET_MODE;
164 }
165 }
166
167
168 /***
169 * This is a method only available within the package for
170 * implementing efficient datagram transport by elminating buffering.
171 * It takes a datagram as an argument, and a byte buffer in which
172 * to store the raw datagram data. Inside the method, the data
173 * is set as the datagram's data and the datagram returned.
174 * <p>
175 * @param datagram The datagram to create.
176 * @param data The buffer to store the packet and to use in the datagram.
177 * @return The datagram argument.
178 ***/
179 @Override
180 final DatagramPacket _newDatagram(DatagramPacket datagram, byte[] data)
181 {
182 int fileLength, modeLength;
183
184 fileLength = _filename.length();
185 modeLength = _modeBytes[_mode].length;
186
187 data[0] = 0;
188 data[1] = (byte)_type;
189 System.arraycopy(_filename.getBytes(), 0, data, 2, fileLength);
190 data[fileLength + 2] = 0;
191 System.arraycopy(_modeBytes[_mode], 0, data, fileLength + 3,
192 modeLength);
193
194 datagram.setAddress(_address);
195 datagram.setPort(_port);
196 datagram.setData(data);
197 datagram.setLength(fileLength + modeLength + 3);
198
199 return datagram;
200 }
201
202 /***
203 * Creates a UDP datagram containing all the TFTP
204 * request packet data in the proper format.
205 * This is a method exposed to the programmer in case he
206 * wants to implement his own TFTP client instead of using
207 * the {@link org.apache.commons.net.tftp.TFTPClient}
208 * class. Under normal circumstances, you should not have a need to call
209 * this method.
210 * <p>
211 * @return A UDP datagram containing the TFTP request packet.
212 ***/
213 @Override
214 public final DatagramPacket newDatagram()
215 {
216 int fileLength, modeLength;
217 byte[] data;
218
219 fileLength = _filename.length();
220 modeLength = _modeBytes[_mode].length;
221
222 data = new byte[fileLength + modeLength + 4];
223 data[0] = 0;
224 data[1] = (byte)_type;
225 System.arraycopy(_filename.getBytes(), 0, data, 2, fileLength);
226 data[fileLength + 2] = 0;
227 System.arraycopy(_modeBytes[_mode], 0, data, fileLength + 3,
228 modeLength);
229
230 return new DatagramPacket(data, data.length, _address, _port);
231 }
232
233 /***
234 * Returns the transfer mode of the request.
235 * <p>
236 * @return The transfer mode of the request.
237 ***/
238 public final int getMode()
239 {
240 return _mode;
241 }
242
243 /***
244 * Returns the requested filename.
245 * <p>
246 * @return The requested filename.
247 ***/
248 public final String getFilename()
249 {
250 return _filename;
251 }
252 }