001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018package org.apache.commons.net.tftp; 019 020import java.net.DatagramPacket; 021import java.net.InetAddress; 022 023/** 024 * An abstract class derived from TFTPPacket definiing a TFTP Request packet type. It is subclassed by the 025 * {@link org.apache.commons.net.tftp.TFTPReadRequestPacket} and {@link org.apache.commons.net.tftp.TFTPWriteRequestPacket} classes. 026 * <p> 027 * 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 028 * 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 029 * should only be concerned with the {@link org.apache.commons.net.tftp.TFTPClient} class {@link org.apache.commons.net.tftp.TFTPClient#receiveFile 030 * receiveFile()} and {@link org.apache.commons.net.tftp.TFTPClient#sendFile sendFile()} methods. 031 * 032 * 033 * @see TFTPPacket 034 * @see TFTPReadRequestPacket 035 * @see TFTPWriteRequestPacket 036 * @see TFTPPacketException 037 * @see TFTP 038 */ 039 040public abstract class TFTPRequestPacket extends TFTPPacket { 041 /** 042 * An array containing the string names of the transfer modes and indexed by the transfer mode constants. 043 */ 044 static final String[] modeStrings = { "netascii", "octet" }; 045 046 /** 047 * A null terminated byte array representation of the ascii names of the transfer mode constants. This is convenient for creating the TFTP request packets. 048 */ 049 private static final byte[] modeBytes[] = { { (byte) 'n', (byte) 'e', (byte) 't', (byte) 'a', (byte) 's', (byte) 'c', (byte) 'i', (byte) 'i', 0 }, 050 { (byte) 'o', (byte) 'c', (byte) 't', (byte) 'e', (byte) 't', 0 } }; 051 052 /** The transfer mode of the request. */ 053 private final int mode; 054 055 /** The file name of the request. */ 056 private final String fileName; 057 058 /** 059 * 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. 060 * 061 * @param destination The host to which the packet is going to be sent. 062 * @param port The port to which the packet is going to be sent. 063 * @param type The type of the request (either TFTPPacket.READ_REQUEST or TFTPPacket.WRITE_REQUEST). 064 * @param fileName The requested file name. 065 * @param mode The requested transfer mode. This should be on of the TFTP class MODE constants (e.g., TFTP.NETASCII_MODE). 066 */ 067 TFTPRequestPacket(final InetAddress destination, final int port, final int type, final String fileName, final int mode) { 068 super(type, destination, port); 069 070 this.fileName = fileName; 071 this.mode = mode; 072 } 073 074 /** 075 * Creates a request packet of a given type based on a received datagram. Assumes the datagram is at least length 4, else an ArrayIndexOutOfBoundsException 076 * may be thrown. 077 * 078 * @param type The type of the request (either TFTPPacket.READ_REQUEST or TFTPPacket.WRITE_REQUEST). 079 * @param datagram The datagram containing the received request. 080 * @throws TFTPPacketException If the datagram isn't a valid TFTP request packet of the appropriate type. 081 */ 082 TFTPRequestPacket(final int type, final DatagramPacket datagram) throws TFTPPacketException { 083 super(type, datagram.getAddress(), datagram.getPort()); 084 085 final byte[] data = datagram.getData(); 086 087 if (getType() != data[1]) { 088 throw new TFTPPacketException("TFTP operator code does not match type."); 089 } 090 091 final StringBuilder buffer = new StringBuilder(); 092 093 int index = 2; 094 int length = datagram.getLength(); 095 096 while (index < length && data[index] != 0) { 097 buffer.append((char) data[index]); 098 ++index; 099 } 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}