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 * A final class derived from TFTPPacket definiing the TFTP Error
025 * packet type.
026 * <p>
027 * Details regarding the TFTP protocol and the format of TFTP packets can
028 * be found in RFC 783. But the point of these classes is to keep you
029 * from having to worry about the internals. Additionally, only very
030 * few people should have to care about any of the TFTPPacket classes
031 * or derived classes. Almost all users should only be concerned with the
032 * {@link org.apache.commons.net.tftp.TFTPClient} class
033 * {@link org.apache.commons.net.tftp.TFTPClient#receiveFile receiveFile()}
034 * and
035 * {@link org.apache.commons.net.tftp.TFTPClient#sendFile sendFile()}
036 * methods.
037 * <p>
038 * <p>
039 * @author Daniel F. Savarese
040 * @see TFTPPacket
041 * @see TFTPPacketException
042 * @see TFTP
043 ***/
044
045 public final class TFTPErrorPacket extends TFTPPacket
046 {
047 /*** The undefined error code according to RFC 783, value 0. ***/
048 public static final int UNDEFINED = 0;
049
050 /*** The file not found error code according to RFC 783, value 1. ***/
051 public static final int FILE_NOT_FOUND = 1;
052
053 /*** The access violation error code according to RFC 783, value 2. ***/
054 public static final int ACCESS_VIOLATION = 2;
055
056 /*** The disk full error code according to RFC 783, value 3. ***/
057 public static final int OUT_OF_SPACE = 3;
058
059 /***
060 * The illegal TFTP operation error code according to RFC 783, value 4.
061 ***/
062 public static final int ILLEGAL_OPERATION = 4;
063
064 /*** The unknown transfer id error code according to RFC 783, value 5. ***/
065 public static final int UNKNOWN_TID = 5;
066
067 /*** The file already exists error code according to RFC 783, value 6. ***/
068 public static final int FILE_EXISTS = 6;
069
070 /*** The no such user error code according to RFC 783, value 7. ***/
071 public static final int NO_SUCH_USER = 7;
072
073 /*** The error code of this packet. ***/
074 int _error;
075
076 /*** The error message of this packet. ***/
077 String _message;
078
079 /***
080 * Creates an error packet to be sent to a host at a given port
081 * with an error code and error message.
082 * <p>
083 * @param destination The host to which the packet is going to be sent.
084 * @param port The port to which the packet is going to be sent.
085 * @param error The error code of the packet.
086 * @param message The error message of the packet.
087 ***/
088 public TFTPErrorPacket(InetAddress destination, int port,
089 int error, String message)
090 {
091 super(TFTPPacket.ERROR, destination, port);
092
093 _error = error;
094 _message = message;
095 }
096
097 /***
098 * Creates an error packet based from a received
099 * datagram. Assumes the datagram is at least length 4, else an
100 * ArrayIndexOutOfBoundsException may be thrown.
101 * <p>
102 * @param datagram The datagram containing the received error.
103 * @throws TFTPPacketException If the datagram isn't a valid TFTP
104 * error packet.
105 ***/
106 TFTPErrorPacket(DatagramPacket datagram) throws TFTPPacketException
107 {
108 super(TFTPPacket.ERROR, datagram.getAddress(), datagram.getPort());
109 int index, length;
110 byte[] data;
111 StringBuffer buffer;
112
113 data = datagram.getData();
114 length = datagram.getLength();
115
116 if (getType() != data[1])
117 throw new TFTPPacketException("TFTP operator code does not match type.");
118
119 _error = (((data[2] & 0xff) << 8) | (data[3] & 0xff));
120
121 if (length < 5)
122 throw new TFTPPacketException("Bad error packet. No message.");
123
124 index = 4;
125 buffer = new StringBuffer();
126
127 while (index < length && data[index] != 0)
128 {
129 buffer.append((char)data[index]);
130 ++index;
131 }
132
133 _message = buffer.toString();
134 }
135
136 /***
137 * This is a method only available within the package for
138 * implementing efficient datagram transport by elminating buffering.
139 * It takes a datagram as an argument, and a byte buffer in which
140 * to store the raw datagram data. Inside the method, the data
141 * is set as the datagram's data and the datagram returned.
142 * <p>
143 * @param datagram The datagram to create.
144 * @param data The buffer to store the packet and to use in the datagram.
145 * @return The datagram argument.
146 ***/
147 @Override
148 DatagramPacket _newDatagram(DatagramPacket datagram, byte[] data)
149 {
150 int length;
151
152 length = _message.length();
153
154 data[0] = 0;
155 data[1] = (byte)_type;
156 data[2] = (byte)((_error & 0xffff) >> 8);
157 data[3] = (byte)(_error & 0xff);
158
159 System.arraycopy(_message.getBytes(), 0, data, 4, length);
160
161 data[length + 4] = 0;
162
163 datagram.setAddress(_address);
164 datagram.setPort(_port);
165 datagram.setData(data);
166 datagram.setLength(length + 4);
167
168 return datagram;
169 }
170
171
172 /***
173 * Creates a UDP datagram containing all the TFTP
174 * error packet data in the proper format.
175 * This is a method exposed to the programmer in case he
176 * wants to implement his own TFTP client instead of using
177 * the {@link org.apache.commons.net.tftp.TFTPClient}
178 * class.
179 * Under normal circumstances, you should not have a need to call this
180 * method.
181 * <p>
182 * @return A UDP datagram containing the TFTP error packet.
183 ***/
184 @Override
185 public DatagramPacket newDatagram()
186 {
187 byte[] data;
188 int length;
189
190 length = _message.length();
191
192 data = new byte[length + 5];
193 data[0] = 0;
194 data[1] = (byte)_type;
195 data[2] = (byte)((_error & 0xffff) >> 8);
196 data[3] = (byte)(_error & 0xff);
197
198 System.arraycopy(_message.getBytes(), 0, data, 4, length);
199
200 data[length + 4] = 0;
201
202 return new DatagramPacket(data, data.length, _address, _port);
203 }
204
205
206 /***
207 * Returns the error code of the packet.
208 * <p>
209 * @return The error code of the packet.
210 ***/
211 public int getError()
212 {
213 return _error;
214 }
215
216
217 /***
218 * Returns the error message of the packet.
219 * <p>
220 * @return The error message of the packet.
221 ***/
222 public String getMessage()
223 {
224 return _message;
225 }
226 }