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 * @author Daniel F. Savarese
044 * @see TFTPPacket
045 * @see TFTPReadRequestPacket
046 * @see TFTPWriteRequestPacket
047 * @see TFTPPacketException
048 * @see TFTP
049 ***/
050
051 public abstract class TFTPRequestPacket extends TFTPPacket
052 {
053 /***
054 * An array containing the string names of the transfer modes and indexed
055 * by the transfer mode constants.
056 ***/
057 static final String[] _modeStrings = { "netascii", "octet" };
058
059 /***
060 * A null terminated byte array representation of the ascii names of the
061 * transfer mode constants. This is convenient for creating the TFTP
062 * request packets.
063 ***/
064 static final byte[] _modeBytes[] = {
065 { (byte)'n', (byte)'e', (byte)'t', (byte)'a', (byte)'s', (byte)'c',
066 (byte)'i', (byte)'i', 0 },
067 { (byte)'o', (byte)'c', (byte)'t', (byte)'e', (byte)'t', 0 }
068 };
069
070 /*** The transfer mode of the request. ***/
071 int _mode;
072
073 /*** The filename of the request. ***/
074 String _filename;
075
076 /***
077 * Creates a request packet of a given type to be sent to a host at a
078 * given port with a filename and transfer mode request.
079 * <p>
080 * @param destination The host to which the packet is going to be sent.
081 * @param port The port to which the packet is going to be sent.
082 * @param type The type of the request (either TFTPPacket.READ_REQUEST or
083 * TFTPPacket.WRITE_REQUEST).
084 * @param filename The requested filename.
085 * @param mode The requested transfer mode. This should be on of the TFTP
086 * class MODE constants (e.g., TFTP.NETASCII_MODE).
087 ***/
088 TFTPRequestPacket(InetAddress destination, int port,
089 int type, String filename, int mode)
090 {
091 super(type, destination, port);
092
093 _filename = filename;
094 _mode = mode;
095 }
096
097 /***
098 * Creates a request packet of a given type based on a received
099 * datagram. Assumes the datagram is at least length 4, else an
100 * ArrayIndexOutOfBoundsException may be thrown.
101 * <p>
102 * @param type The type of the request (either TFTPPacket.READ_REQUEST or
103 * TFTPPacket.WRITE_REQUEST).
104 * @param datagram The datagram containing the received request.
105 * @throws TFTPPacketException If the datagram isn't a valid TFTP
106 * request packet of the appropriate type.
107 ***/
108 TFTPRequestPacket(int type, DatagramPacket datagram)
109 throws TFTPPacketException
110 {
111 super(type, datagram.getAddress(), datagram.getPort());
112
113 byte[] data;
114 int index, length;
115 String mode;
116 StringBuffer buffer;
117
118 data = datagram.getData();
119
120 if (getType() != data[1])
121 throw new TFTPPacketException("TFTP operator code does not match type.");
122
123 buffer = new StringBuffer();
124
125 index = 2;
126 length = datagram.getLength();
127
128 while (index < length && data[index] != 0)
129 {
130 buffer.append((char)data[index]);
131 ++index;
132 }
133
134 _filename = buffer.toString();
135
136 if (index >= length)
137 throw new TFTPPacketException("Bad filename and mode format.");
138
139 buffer.setLength(0);
140 ++index; // need to advance beyond the end of string marker
141 while (index < length && data[index] != 0)
142 {
143 buffer.append((char)data[index]);
144 ++index;
145 }
146
147 mode = buffer.toString().toLowerCase(java.util.Locale.ENGLISH);
148 length = _modeStrings.length;
149
150 for (index = 0; index < length; index++)
151 {
152 if (mode.equals(_modeStrings[index]))
153 {
154 _mode = index;
155 break;
156 }
157 }
158
159 if (index >= length)
160 {
161 throw new TFTPPacketException("Unrecognized TFTP transfer mode: " + mode);
162 // May just want to default to binary mode instead of throwing
163 // exception.
164 //_mode = TFTP.OCTET_MODE;
165 }
166 }
167
168
169 /***
170 * This is a method only available within the package for
171 * implementing efficient datagram transport by elminating buffering.
172 * It takes a datagram as an argument, and a byte buffer in which
173 * to store the raw datagram data. Inside the method, the data
174 * is set as the datagram's data and the datagram returned.
175 * <p>
176 * @param datagram The datagram to create.
177 * @param data The buffer to store the packet and to use in the datagram.
178 * @return The datagram argument.
179 ***/
180 @Override
181 final DatagramPacket _newDatagram(DatagramPacket datagram, byte[] data)
182 {
183 int fileLength, modeLength;
184
185 fileLength = _filename.length();
186 modeLength = _modeBytes[_mode].length;
187
188 data[0] = 0;
189 data[1] = (byte)_type;
190 System.arraycopy(_filename.getBytes(), 0, data, 2, fileLength);
191 data[fileLength + 2] = 0;
192 System.arraycopy(_modeBytes[_mode], 0, data, fileLength + 3,
193 modeLength);
194
195 datagram.setAddress(_address);
196 datagram.setPort(_port);
197 datagram.setData(data);
198 datagram.setLength(fileLength + modeLength + 3);
199
200 return datagram;
201 }
202
203 /***
204 * Creates a UDP datagram containing all the TFTP
205 * request packet data in the proper format.
206 * This is a method exposed to the programmer in case he
207 * wants to implement his own TFTP client instead of using
208 * the {@link org.apache.commons.net.tftp.TFTPClient}
209 * class. Under normal circumstances, you should not have a need to call
210 * this method.
211 * <p>
212 * @return A UDP datagram containing the TFTP request packet.
213 ***/
214 @Override
215 public final DatagramPacket newDatagram()
216 {
217 int fileLength, modeLength;
218 byte[] data;
219
220 fileLength = _filename.length();
221 modeLength = _modeBytes[_mode].length;
222
223 data = new byte[fileLength + modeLength + 4];
224 data[0] = 0;
225 data[1] = (byte)_type;
226 System.arraycopy(_filename.getBytes(), 0, data, 2, fileLength);
227 data[fileLength + 2] = 0;
228 System.arraycopy(_modeBytes[_mode], 0, data, fileLength + 3,
229 modeLength);
230
231 return new DatagramPacket(data, data.length, _address, _port);
232 }
233
234 /***
235 * Returns the transfer mode of the request.
236 * <p>
237 * @return The transfer mode of the request.
238 ***/
239 public final int getMode()
240 {
241 return _mode;
242 }
243
244 /***
245 * Returns the requested filename.
246 * <p>
247 * @return The requested filename.
248 ***/
249 public final String getFilename()
250 {
251 return _filename;
252 }
253 }