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