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1 package org.apache.commons.net.tftp; 2 3 /* ==================================================================== 4 * The Apache Software License, Version 1.1 5 * 6 * Copyright (c) 2001 The Apache Software Foundation. All rights 7 * reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in 18 * the documentation and/or other materials provided with the 19 * distribution. 20 * 21 * 3. The end-user documentation included with the redistribution, 22 * if any, must include the following acknowledgment: 23 * "This product includes software developed by the 24 * Apache Software Foundation (http://www.apache.org/)." 25 * Alternately, this acknowledgment may appear in the software itself, 26 * if and wherever such third-party acknowledgments normally appear. 27 * 28 * 4. The names "Apache" and "Apache Software Foundation" and 29 * "Apache Commons" must not be used to endorse or promote products 30 * derived from this software without prior written permission. For 31 * written permission, please contact apache@apache.org. 32 * 33 * 5. Products derived from this software may not be called "Apache", 34 * nor may "Apache" appear in their name, without 35 * prior written permission of the Apache Software Foundation. 36 * 37 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED 38 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 39 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 40 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR 41 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 42 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 43 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 44 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 45 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 46 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 47 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 48 * SUCH DAMAGE. 49 * ==================================================================== 50 * 51 * This software consists of voluntary contributions made by many 52 * individuals on behalf of the Apache Software Foundation. For more 53 * information on the Apache Software Foundation, please see 54 * <http://www.apache.org/>;. 55 */ 56 57 import java.net.DatagramPacket; 58 import java.net.InetAddress; 59 60 /**** 61 * A final class derived from TFTPPacket definiing the TFTP Data 62 * packet type. 63 * <p> 64 * Details regarding the TFTP protocol and the format of TFTP packets can 65 * be found in RFC 783. But the point of these classes is to keep you 66 * from having to worry about the internals. Additionally, only very 67 * few people should have to care about any of the TFTPPacket classes 68 * or derived classes. Almost all users should only be concerned with the 69 * <a href="org.apache.commons.net.tftp.TFTPClient.html#_top_">TFTPClient</a> class 70 * <a href="org.apache.commons.net.tftp.TFTPClient.html#receiveFile">receiveFile()</a> 71 * and 72 * <a href="org.apache.commons.net.tftp.TFTPClient.html#sendFile">sendFile()</a> 73 * methods. 74 * <p> 75 * <p> 76 * @author Daniel F. Savarese 77 * @see TFTPPacket 78 * @see TFTPPacketException 79 * @see TFTP 80 ***/ 81 82 public final class TFTPDataPacket extends TFTPPacket 83 { 84 /**** The maximum number of bytes in a TFTP data packet (512) ***/ 85 public static final int MAX_DATA_LENGTH = 512; 86 87 /**** The minimum number of bytes in a TFTP data packet (0) ***/ 88 public static final int MIN_DATA_LENGTH = 0; 89 90 /**** The block number of the packet. ***/ 91 int _blockNumber; 92 93 /**** The length of the data. ***/ 94 int _length; 95 96 /**** The offset into the _data array at which the data begins. ***/ 97 int _offset; 98 99 /**** The data stored in the packet. ***/ 100 byte[] _data; 101 102 /**** 103 * Creates a data packet to be sent to a host at a given port 104 * with a given block number. The actual data to be sent is passed as 105 * an array, an offset, and a length. The offset is the offset into 106 * the byte array where the data starts. The length is the length of 107 * the data. If the length is greater than MAX_DATA_LENGTH, it is 108 * truncated. 109 * <p> 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 blockNumber The block number of the data. 113 * @param data The byte array containing the data. 114 * @param offset The offset into the array where the data starts. 115 * @param length The length of the data. 116 ***/ 117 public TFTPDataPacket(InetAddress destination, int port, int blockNumber, 118 byte[] data, int offset, int length) 119 { 120 super(TFTPPacket.DATA, destination, port); 121 122 _blockNumber = blockNumber; 123 _data = data; 124 _offset = offset; 125 126 if (length > MAX_DATA_LENGTH) 127 _length = MAX_DATA_LENGTH; 128 else 129 _length = length; 130 } 131 132 public TFTPDataPacket(InetAddress destination, int port, int blockNumber, 133 byte[] data) 134 { 135 this(destination, port, blockNumber, data, 0, data.length); 136 } 137 138 139 /**** 140 * Creates a data packet based from a received 141 * datagram. Assumes the datagram is at least length 4, else an 142 * ArrayIndexOutOfBoundsException may be thrown. 143 * <p> 144 * @param datagram The datagram containing the received data. 145 * @throws TFTPPacketException If the datagram isn't a valid TFTP 146 * data packet. 147 ***/ 148 TFTPDataPacket(DatagramPacket datagram) throws TFTPPacketException 149 { 150 super(TFTPPacket.DATA, datagram.getAddress(), datagram.getPort()); 151 152 _data = datagram.getData(); 153 _offset = 4; 154 155 if (getType() != _data[1]) 156 throw new TFTPPacketException("TFTP operator code does not match type."); 157 158 _blockNumber = (((_data[2] & 0xff) << 8) | (_data[3] & 0xff)); 159 160 _length = datagram.getLength() - 4; 161 162 if (_length > MAX_DATA_LENGTH) 163 _length = MAX_DATA_LENGTH; 164 } 165 166 /**** 167 * This is a method only available within the package for 168 * implementing efficient datagram transport by elminating buffering. 169 * It takes a datagram as an argument, and a byte buffer in which 170 * to store the raw datagram data. Inside the method, the data 171 * is set as the datagram's data and the datagram returned. 172 * <p> 173 * @param datagram The datagram to create. 174 * @param data The buffer to store the packet and to use in the datagram. 175 * @return The datagram argument. 176 ***/ 177 DatagramPacket _newDatagram(DatagramPacket datagram, byte[] data) 178 { 179 data[0] = 0; 180 data[1] = (byte)_type; 181 data[2] = (byte)((_blockNumber & 0xffff) >> 8); 182 data[3] = (byte)(_blockNumber & 0xff); 183 184 // Doublecheck we're not the same 185 if (data != _data) 186 System.arraycopy(_data, _offset, data, 4, _length); 187 188 datagram.setAddress(_address); 189 datagram.setPort(_port); 190 datagram.setData(data); 191 datagram.setLength(_length + 4); 192 193 return datagram; 194 } 195 196 /**** 197 * Creates a UDP datagram containing all the TFTP 198 * data packet data in the proper format. 199 * This is a method exposed to the programmer in case he 200 * wants to implement his own TFTP client instead of using 201 * the <a href="org.apache.commons.net.tftp.TFTPClient.html#_top_">TFTPClient</a> 202 * class. 203 * Under normal circumstances, you should not have a need to call this 204 * method. 205 * <p> 206 * @return A UDP datagram containing the TFTP data packet. 207 ***/ 208 public DatagramPacket newDatagram() 209 { 210 byte[] data; 211 DatagramPacket datagram; 212 213 data = new byte[_length + 4]; 214 data[0] = 0; 215 data[1] = (byte)_type; 216 data[2] = (byte)((_blockNumber & 0xffff) >> 8); 217 data[3] = (byte)(_blockNumber & 0xff); 218 219 System.arraycopy(_data, _offset, data, 4, _length); 220 221 return new DatagramPacket(data, _length + 4, _address, _port); 222 } 223 224 /**** 225 * Returns the block number of the data packet. 226 * <p> 227 * @return The block number of the data packet. 228 ***/ 229 public int getBlockNumber() 230 { 231 return _blockNumber; 232 } 233 234 /**** Sets the block number of the data packet. ***/ 235 public void setBlockNumber(int blockNumber) 236 { 237 _blockNumber = blockNumber; 238 } 239 240 /**** 241 * Sets the data for the data packet. 242 * <p> 243 * @param data The byte array containing the data. 244 * @param offset The offset into the array where the data starts. 245 * @param length The length of the data. 246 ***/ 247 public void setData(byte[] data, int offset, int length) 248 { 249 _data = data; 250 _offset = offset; 251 _length = length; 252 253 if (length > MAX_DATA_LENGTH) 254 _length = MAX_DATA_LENGTH; 255 else 256 _length = length; 257 } 258 259 /**** 260 * Returns the length of the data part of the data packet. 261 * <p> 262 * @return The length of the data part of the data packet. 263 ***/ 264 public int getDataLength() 265 { 266 return _length; 267 } 268 269 /**** 270 * Returns the offset into the byte array where the packet data actually 271 * starts. 272 * <p> 273 * @return The offset into the byte array where the packet data actually 274 * starts. 275 ***/ 276 public int getDataOffset() 277 { 278 return _offset; 279 } 280 281 /**** 282 * Returns the byte array containing the packet data. 283 * <p> 284 * @return The byte array containing the packet data. 285 ***/ 286 public byte[] getData() 287 { 288 return _data; 289 } 290 }

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