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.net.DatagramPacket;
21 import java.net.InetAddress;
22
23 /**
24 * A final class derived from TFTPPacket defining the TFTP Error packet type.
25 * <p>
26 * Details regarding the TFTP protocol and the format of TFTP packets can be found in RFC 783. But the point of these classes is to keep you from having to
27 * worry about the internals. Additionally, only very few people should have to care about any of the TFTPPacket classes or derived classes. Almost all users
28 * should only be concerned with the {@link org.apache.commons.net.tftp.TFTPClient} class {@link org.apache.commons.net.tftp.TFTPClient#receiveFile
29 * receiveFile()} and {@link org.apache.commons.net.tftp.TFTPClient#sendFile sendFile()} methods.
30 *
31 *
32 * @see TFTPPacket
33 * @see TFTPPacketException
34 * @see TFTP
35 */
36
37 public final class TFTPErrorPacket extends TFTPPacket {
38 /** The undefined error code according to RFC 783, value 0. */
39 public static final int UNDEFINED = 0;
40
41 /** The file not found error code according to RFC 783, value 1. */
42 public static final int FILE_NOT_FOUND = 1;
43
44 /** The access violation error code according to RFC 783, value 2. */
45 public static final int ACCESS_VIOLATION = 2;
46
47 /** The disk full error code according to RFC 783, value 3. */
48 public static final int OUT_OF_SPACE = 3;
49
50 /**
51 * The illegal TFTP operation error code according to RFC 783, value 4.
52 */
53 public static final int ILLEGAL_OPERATION = 4;
54
55 /** The unknown transfer id error code according to RFC 783, value 5. */
56 public static final int UNKNOWN_TID = 5;
57
58 /** The file already exists error code according to RFC 783, value 6. */
59 public static final int FILE_EXISTS = 6;
60
61 /** The no such user error code according to RFC 783, value 7. */
62 public static final int NO_SUCH_USER = 7;
63
64 /** The error code of this packet. */
65 private final int error;
66
67 /** The error message of this packet. */
68 private final String message;
69
70 /**
71 * Creates an error packet based from a received datagram. Assumes the datagram is at least length 4, else an ArrayIndexOutOfBoundsException may be thrown.
72 *
73 * @param datagram The datagram containing the received error.
74 * @throws TFTPPacketException If the datagram isn't a valid TFTP error packet.
75 */
76 TFTPErrorPacket(final DatagramPacket datagram) throws TFTPPacketException {
77 super(TFTPPacket.ERROR, datagram.getAddress(), datagram.getPort());
78 int index;
79 final int length;
80 final byte[] data;
81 final StringBuilder buffer;
82
83 data = datagram.getData();
84 length = datagram.getLength();
85
86 if (getType() != data[1]) {
87 throw new TFTPPacketException("TFTP operator code does not match type.");
88 }
89
90 error = (data[2] & 0xff) << 8 | data[3] & 0xff;
91
92 if (length < 5) {
93 throw new TFTPPacketException("Bad error packet. No message.");
94 }
95
96 index = 4;
97 buffer = new StringBuilder();
98
99 while (index < length && data[index] != 0) {
100 buffer.append((char) data[index]);
101 ++index;
102 }
103
104 message = buffer.toString();
105 }
106
107 /**
108 * Creates an error packet to be sent to a host at a given port with an error code and error message.
109 *
110 * @param destination The host to which the packet is going to be sent.
111 * @param port The port to which the packet is going to be sent.
112 * @param error The error code of the packet.
113 * @param message The error message of the packet.
114 */
115 public TFTPErrorPacket(final InetAddress destination, final int port, final int error, final String message) {
116 super(TFTPPacket.ERROR, destination, port);
117
118 this.error = error;
119 this.message = message;
120 }
121
122 /**
123 * Returns the error code of the packet.
124 *
125 * @return The error code of the packet.
126 */
127 public int getError() {
128 return error;
129 }
130
131 /**
132 * Returns the error message of the packet.
133 *
134 * @return The error message of the packet.
135 */
136 public String getMessage() {
137 return message;
138 }
139
140 /**
141 * Creates a UDP datagram containing all the TFTP error packet data in the proper format. This is a method exposed to the programmer in case he wants to
142 * implement his own TFTP client instead of using the {@link org.apache.commons.net.tftp.TFTPClient} class. Under normal circumstances, you should not have
143 * a need to call this method.
144 *
145 * @return A UDP datagram containing the TFTP error packet.
146 */
147 @Override
148 public DatagramPacket newDatagram() {
149 final byte[] data;
150 final int length;
151
152 length = message.length();
153
154 data = new byte[length + 5];
155 data[0] = 0;
156 data[1] = (byte) type;
157 data[2] = (byte) ((error & 0xffff) >> 8);
158 data[3] = (byte) (error & 0xff);
159
160 System.arraycopy(message.getBytes(), 0, data, 4, length);
161
162 data[length + 4] = 0;
163
164 return new DatagramPacket(data, data.length, address, port);
165 }
166
167 /**
168 * This is a method only available within the package for implementing efficient datagram transport by eliminating buffering. It takes a datagram as an
169 * argument, and a byte buffer in which to store the raw datagram data. Inside the method, the data is set as the datagram's data and the datagram returned.
170 *
171 * @param datagram The datagram to create.
172 * @param data The buffer to store the packet and to use in the datagram.
173 * @return The datagram argument.
174 */
175 @Override
176 DatagramPacket newDatagram(final DatagramPacket datagram, final byte[] data) {
177 final int length;
178
179 length = message.length();
180
181 data[0] = 0;
182 data[1] = (byte) type;
183 data[2] = (byte) ((error & 0xffff) >> 8);
184 data[3] = (byte) (error & 0xff);
185
186 System.arraycopy(message.getBytes(), 0, data, 4, length);
187
188 data[length + 4] = 0;
189
190 datagram.setAddress(address);
191 datagram.setPort(port);
192 datagram.setData(data);
193 datagram.setLength(length + 4);
194
195 return datagram;
196 }
197
198 /**
199 * For debugging
200 *
201 * @since 3.6
202 */
203 @Override
204 public String toString() {
205 return super.toString() + " ERR " + error + " " + message;
206 }
207 }