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 * An abstract class derived from TFTPPacket definiing a TFTP Request packet type. It is subclassed by the
25 * {@link org.apache.commons.net.tftp.TFTPReadRequestPacket} and {@link org.apache.commons.net.tftp.TFTPWriteRequestPacket} classes.
26 * <p>
27 * 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
28 * 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
29 * should only be concerned with the {@link org.apache.commons.net.tftp.TFTPClient} class {@link org.apache.commons.net.tftp.TFTPClient#receiveFile
30 * receiveFile()} and {@link org.apache.commons.net.tftp.TFTPClient#sendFile sendFile()} methods.
31 *
32 *
33 * @see TFTPPacket
34 * @see TFTPReadRequestPacket
35 * @see TFTPWriteRequestPacket
36 * @see TFTPPacketException
37 * @see TFTP
38 */
39
40 public abstract class TFTPRequestPacket extends TFTPPacket {
41 /**
42 * An array containing the string names of the transfer modes and indexed by the transfer mode constants.
43 */
44 static final String[] modeStrings = { "netascii", "octet" };
45
46 /**
47 * A null terminated byte array representation of the ascii names of the transfer mode constants. This is convenient for creating the TFTP request packets.
48 */
49 private static final byte[] modeBytes[] = { { (byte) 'n', (byte) 'e', (byte) 't', (byte) 'a', (byte) 's', (byte) 'c', (byte) 'i', (byte) 'i', 0 },
50 { (byte) 'o', (byte) 'c', (byte) 't', (byte) 'e', (byte) 't', 0 } };
51
52 /** The transfer mode of the request. */
53 private final int mode;
54
55 /** The file name of the request. */
56 private final String fileName;
57
58 /**
59 * Creates a request packet of a given type to be sent to a host at a given port with a file name and transfer mode request.
60 *
61 * @param destination The host to which the packet is going to be sent.
62 * @param port The port to which the packet is going to be sent.
63 * @param type The type of the request (either TFTPPacket.READ_REQUEST or TFTPPacket.WRITE_REQUEST).
64 * @param fileName The requested file name.
65 * @param mode The requested transfer mode. This should be on of the TFTP class MODE constants (e.g., TFTP.NETASCII_MODE).
66 */
67 TFTPRequestPacket(final InetAddress destination, final int port, final int type, final String fileName, final int mode) {
68 super(type, destination, port);
69
70 this.fileName = fileName;
71 this.mode = mode;
72 }
73
74 /**
75 * Creates a request packet of a given type based on a received datagram. Assumes the datagram is at least length 4, else an ArrayIndexOutOfBoundsException
76 * may be thrown.
77 *
78 * @param type The type of the request (either TFTPPacket.READ_REQUEST or TFTPPacket.WRITE_REQUEST).
79 * @param datagram The datagram containing the received request.
80 * @throws TFTPPacketException If the datagram isn't a valid TFTP request packet of the appropriate type.
81 */
82 TFTPRequestPacket(final int type, final DatagramPacket datagram) throws TFTPPacketException {
83 super(type, datagram.getAddress(), datagram.getPort());
84
85 final byte[] data = datagram.getData();
86
87 if (getType() != data[1]) {
88 throw new TFTPPacketException("TFTP operator code does not match type.");
89 }
90
91 final StringBuilder buffer = new StringBuilder();
92
93 int index = 2;
94 int length = datagram.getLength();
95
96 while (index < length && data[index] != 0) {
97 buffer.append((char) data[index]);
98 ++index;
99 }
100
101 this.fileName = buffer.toString();
102
103 if (index >= length) {
104 throw new TFTPPacketException("Bad file name and mode format.");
105 }
106
107 buffer.setLength(0);
108 ++index; // need to advance beyond the end of string marker
109 while (index < length && data[index] != 0) {
110 buffer.append((char) data[index]);
111 ++index;
112 }
113
114 final String modeString = buffer.toString().toLowerCase(java.util.Locale.ENGLISH);
115 length = modeStrings.length;
116
117 int mode = 0;
118 for (index = 0; index < length; index++) {
119 if (modeString.equals(modeStrings[index])) {
120 mode = index;
121 break;
122 }
123 }
124
125 this.mode = mode;
126
127 if (index >= length) {
128 throw new TFTPPacketException("Unrecognized TFTP transfer mode: " + modeString);
129 // May just want to default to binary mode instead of throwing
130 // exception.
131 // _mode = TFTP.OCTET_MODE;
132 }
133 }
134
135 /**
136 * Returns the requested file name.
137 *
138 * @return The requested file name.
139 */
140 public final String getFilename() {
141 return fileName;
142 }
143
144 /**
145 * Returns the transfer mode of the request.
146 *
147 * @return The transfer mode of the request.
148 */
149 public final int getMode() {
150 return mode;
151 }
152
153 /**
154 * Creates a UDP datagram containing all the TFTP request packet data in the proper format. This is a method exposed to the programmer in case he wants to
155 * implement his own TFTP client instead of using the {@link org.apache.commons.net.tftp.TFTPClient} class. Under normal circumstances, you should not have
156 * a need to call this method.
157 *
158 * @return A UDP datagram containing the TFTP request packet.
159 */
160 @Override
161 public final DatagramPacket newDatagram() {
162 final int fileLength;
163 final int modeLength;
164 final byte[] data;
165
166 fileLength = fileName.length();
167 modeLength = modeBytes[mode].length;
168
169 data = new byte[fileLength + modeLength + 4];
170 data[0] = 0;
171 data[1] = (byte) type;
172 System.arraycopy(fileName.getBytes(), 0, data, 2, fileLength);
173 data[fileLength + 2] = 0;
174 System.arraycopy(modeBytes[mode], 0, data, fileLength + 3, modeLength);
175
176 return new DatagramPacket(data, data.length, address, port);
177 }
178
179 /**
180 * This is a method only available within the package for implementing efficient datagram transport by elminating buffering. It takes a datagram as an
181 * 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.
182 *
183 * @param datagram The datagram to create.
184 * @param data The buffer to store the packet and to use in the datagram.
185 * @return The datagram argument.
186 */
187 @Override
188 final DatagramPacket newDatagram(final DatagramPacket datagram, final byte[] data) {
189 final int fileLength;
190 final int modeLength;
191
192 fileLength = fileName.length();
193 modeLength = modeBytes[mode].length;
194
195 data[0] = 0;
196 data[1] = (byte) type;
197 System.arraycopy(fileName.getBytes(), 0, data, 2, fileLength);
198 data[fileLength + 2] = 0;
199 System.arraycopy(modeBytes[mode], 0, data, fileLength + 3, modeLength);
200
201 datagram.setAddress(address);
202 datagram.setPort(port);
203 datagram.setData(data);
204 datagram.setLength(fileLength + modeLength + 3);
205
206 return datagram;
207 }
208 }