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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 Acknowledgement 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 TFTPAckPacket extends TFTPPacket 83 { 84 /**** The block number being acknowledged by the packet. ***/ 85 int _blockNumber; 86 87 /**** 88 * Creates an acknowledgment packet to be sent to a host at a given port 89 * acknowledging receipt of a block. 90 * <p> 91 * @param destination The host to which the packet is going to be sent. 92 * @param port The port to which the packet is going to be sent. 93 * @param blockNumber The block number being acknowledged. 94 ***/ 95 public TFTPAckPacket(InetAddress destination, int port, int blockNumber) 96 { 97 super(TFTPPacket.ACKNOWLEDGEMENT, destination, port); 98 _blockNumber = blockNumber; 99 } 100 101 /**** 102 * Creates an acknowledgement packet based from a received 103 * datagram. Assumes the datagram is at least length 4, else an 104 * ArrayIndexOutOfBoundsException may be thrown. 105 * <p> 106 * @param datagram The datagram containing the received acknowledgement. 107 * @throws TFTPPacketException If the datagram isn't a valid TFTP 108 * acknowledgement packet. 109 ***/ 110 TFTPAckPacket(DatagramPacket datagram) throws TFTPPacketException 111 { 112 super(TFTPPacket.ACKNOWLEDGEMENT, datagram.getAddress(), 113 datagram.getPort()); 114 byte[] data; 115 116 data = datagram.getData(); 117 118 if (getType() != data[1]) 119 throw new TFTPPacketException("TFTP operator code does not match type."); 120 121 _blockNumber = (((data[2] & 0xff) << 8) | (data[3] & 0xff)); 122 } 123 124 /**** 125 * This is a method only available within the package for 126 * implementing efficient datagram transport by elminating buffering. 127 * It takes a datagram as an argument, and a byte buffer in which 128 * to store the raw datagram data. Inside the method, the data 129 * is set as the datagram's data and the datagram returned. 130 * <p> 131 * @param datagram The datagram to create. 132 * @param data The buffer to store the packet and to use in the datagram. 133 * @return The datagram argument. 134 ***/ 135 DatagramPacket _newDatagram(DatagramPacket datagram, byte[] data) 136 { 137 data[0] = 0; 138 data[1] = (byte)_type; 139 data[2] = (byte)((_blockNumber & 0xffff) >> 8); 140 data[3] = (byte)(_blockNumber & 0xff); 141 142 datagram.setAddress(_address); 143 datagram.setPort(_port); 144 datagram.setData(data); 145 datagram.setLength(4); 146 147 return datagram; 148 } 149 150 151 /**** 152 * Creates a UDP datagram containing all the TFTP 153 * acknowledgement packet data in the proper format. 154 * This is a method exposed to the programmer in case he 155 * wants to implement his own TFTP client instead of using 156 * the <a href="org.apache.commons.net.tftp.TFTPClient.html#_top_">TFTPClient</a> 157 * class. Under normal circumstances, you should not have a need to call this 158 * method. 159 * <p> 160 * @return A UDP datagram containing the TFTP acknowledgement packet. 161 ***/ 162 public DatagramPacket newDatagram() 163 { 164 byte[] data; 165 166 data = new byte[4]; 167 data[0] = 0; 168 data[1] = (byte)_type; 169 data[2] = (byte)((_blockNumber & 0xffff) >> 8); 170 data[3] = (byte)(_blockNumber & 0xff); 171 172 return new DatagramPacket(data, data.length, _address, _port); 173 } 174 175 176 /**** 177 * Returns the block number of the acknowledgement. 178 * <p> 179 * @return The block number of the acknowledgement. 180 ***/ 181 public int getBlockNumber() 182 { 183 return _blockNumber; 184 } 185 186 187 /**** Sets the block number of the acknowledgement. ***/ 188 public void setBlockNumber(int blockNumber) 189 { 190 _blockNumber = blockNumber; 191 } 192 } 193

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