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 25 * packet type. It is subclassed by the 26 * {@link org.apache.commons.net.tftp.TFTPReadRequestPacket} 27 * and 28 * {@link org.apache.commons.net.tftp.TFTPWriteRequestPacket} 29 * classes. 30 * <p> 31 * Details regarding the TFTP protocol and the format of TFTP packets can 32 * be found in RFC 783. But the point of these classes is to keep you 33 * from having to worry about the internals. Additionally, only very 34 * few people should have to care about any of the TFTPPacket classes 35 * or derived classes. Almost all users should only be concerned with the 36 * {@link org.apache.commons.net.tftp.TFTPClient} class 37 * {@link org.apache.commons.net.tftp.TFTPClient#receiveFile receiveFile()} 38 * and 39 * {@link org.apache.commons.net.tftp.TFTPClient#sendFile sendFile()} 40 * methods. 41 * <p> 42 * <p> 43 * @author Daniel F. Savarese 44 * @see TFTPPacket 45 * @see TFTPReadRequestPacket 46 * @see TFTPWriteRequestPacket 47 * @see TFTPPacketException 48 * @see TFTP 49 ***/ 50 51 public abstract class TFTPRequestPacket extends TFTPPacket 52 { 53 /*** 54 * An array containing the string names of the transfer modes and indexed 55 * by the transfer mode constants. 56 ***/ 57 static final String[] _modeStrings = { "netascii", "octet" }; 58 59 /*** 60 * A null terminated byte array representation of the ascii names of the 61 * transfer mode constants. This is convenient for creating the TFTP 62 * request packets. 63 ***/ 64 static final byte[] _modeBytes[] = { 65 { (byte)'n', (byte)'e', (byte)'t', (byte)'a', (byte)'s', (byte)'c', 66 (byte)'i', (byte)'i', 0 }, 67 { (byte)'o', (byte)'c', (byte)'t', (byte)'e', (byte)'t', 0 } 68 }; 69 70 /*** The transfer mode of the request. ***/ 71 int _mode; 72 73 /*** The filename of the request. ***/ 74 String _filename; 75 76 /*** 77 * Creates a request packet of a given type to be sent to a host at a 78 * given port with a filename and transfer mode request. 79 * <p> 80 * @param destination The host to which the packet is going to be sent. 81 * @param port The port to which the packet is going to be sent. 82 * @param type The type of the request (either TFTPPacket.READ_REQUEST or 83 * TFTPPacket.WRITE_REQUEST). 84 * @param filename The requested filename. 85 * @param mode The requested transfer mode. This should be on of the TFTP 86 * class MODE constants (e.g., TFTP.NETASCII_MODE). 87 ***/ 88 TFTPRequestPacket(InetAddress destination, int port, 89 int type, String filename, int mode) 90 { 91 super(type, destination, port); 92 93 _filename = filename; 94 _mode = mode; 95 } 96 97 /*** 98 * Creates a request packet of a given type based on a received 99 * datagram. Assumes the datagram is at least length 4, else an 100 * ArrayIndexOutOfBoundsException may be thrown. 101 * <p> 102 * @param type The type of the request (either TFTPPacket.READ_REQUEST or 103 * TFTPPacket.WRITE_REQUEST). 104 * @param datagram The datagram containing the received request. 105 * @throws TFTPPacketException If the datagram isn't a valid TFTP 106 * request packet of the appropriate type. 107 ***/ 108 TFTPRequestPacket(int type, DatagramPacket datagram) 109 throws TFTPPacketException 110 { 111 super(type, datagram.getAddress(), datagram.getPort()); 112 113 byte[] data; 114 int index, length; 115 String mode; 116 StringBuffer buffer; 117 118 data = datagram.getData(); 119 120 if (getType() != data[1]) 121 throw new TFTPPacketException("TFTP operator code does not match type."); 122 123 buffer = new StringBuffer(); 124 125 index = 2; 126 length = datagram.getLength(); 127 128 while (index < length && data[index] != 0) 129 { 130 buffer.append((char)data[index]); 131 ++index; 132 } 133 134 _filename = buffer.toString(); 135 136 if (index >= length) 137 throw new TFTPPacketException("Bad filename and mode format."); 138 139 buffer.setLength(0); 140 ++index; // need to advance beyond the end of string marker 141 while (index < length && data[index] != 0) 142 { 143 buffer.append((char)data[index]); 144 ++index; 145 } 146 147 mode = buffer.toString().toLowerCase(java.util.Locale.ENGLISH); 148 length = _modeStrings.length; 149 150 for (index = 0; index < length; index++) 151 { 152 if (mode.equals(_modeStrings[index])) 153 { 154 _mode = index; 155 break; 156 } 157 } 158 159 if (index >= length) 160 { 161 throw new TFTPPacketException("Unrecognized TFTP transfer mode: " + mode); 162 // May just want to default to binary mode instead of throwing 163 // exception. 164 //_mode = TFTP.OCTET_MODE; 165 } 166 } 167 168 169 /*** 170 * This is a method only available within the package for 171 * implementing efficient datagram transport by elminating buffering. 172 * It takes a datagram as an argument, and a byte buffer in which 173 * to store the raw datagram data. Inside the method, the data 174 * is set as the datagram's data and the datagram returned. 175 * <p> 176 * @param datagram The datagram to create. 177 * @param data The buffer to store the packet and to use in the datagram. 178 * @return The datagram argument. 179 ***/ 180 @Override 181 final DatagramPacket _newDatagram(DatagramPacket datagram, byte[] data) 182 { 183 int fileLength, modeLength; 184 185 fileLength = _filename.length(); 186 modeLength = _modeBytes[_mode].length; 187 188 data[0] = 0; 189 data[1] = (byte)_type; 190 System.arraycopy(_filename.getBytes(), 0, data, 2, fileLength); 191 data[fileLength + 2] = 0; 192 System.arraycopy(_modeBytes[_mode], 0, data, fileLength + 3, 193 modeLength); 194 195 datagram.setAddress(_address); 196 datagram.setPort(_port); 197 datagram.setData(data); 198 datagram.setLength(fileLength + modeLength + 3); 199 200 return datagram; 201 } 202 203 /*** 204 * Creates a UDP datagram containing all the TFTP 205 * request packet data in the proper format. 206 * This is a method exposed to the programmer in case he 207 * wants to implement his own TFTP client instead of using 208 * the {@link org.apache.commons.net.tftp.TFTPClient} 209 * class. Under normal circumstances, you should not have a need to call 210 * this method. 211 * <p> 212 * @return A UDP datagram containing the TFTP request packet. 213 ***/ 214 @Override 215 public final DatagramPacket newDatagram() 216 { 217 int fileLength, modeLength; 218 byte[] data; 219 220 fileLength = _filename.length(); 221 modeLength = _modeBytes[_mode].length; 222 223 data = new byte[fileLength + modeLength + 4]; 224 data[0] = 0; 225 data[1] = (byte)_type; 226 System.arraycopy(_filename.getBytes(), 0, data, 2, fileLength); 227 data[fileLength + 2] = 0; 228 System.arraycopy(_modeBytes[_mode], 0, data, fileLength + 3, 229 modeLength); 230 231 return new DatagramPacket(data, data.length, _address, _port); 232 } 233 234 /*** 235 * Returns the transfer mode of the request. 236 * <p> 237 * @return The transfer mode of the request. 238 ***/ 239 public final int getMode() 240 { 241 return _mode; 242 } 243 244 /*** 245 * Returns the requested filename. 246 * <p> 247 * @return The requested filename. 248 ***/ 249 public final String getFilename() 250 { 251 return _filename; 252 } 253 }