TFTPErrorPacket.java
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.net.tftp;
import java.net.DatagramPacket;
import java.net.InetAddress;
/**
* A final class derived from TFTPPacket defining the TFTP Error packet type.
* <p>
* 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
* 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
* should only be concerned with the {@link org.apache.commons.net.tftp.TFTPClient} class {@link org.apache.commons.net.tftp.TFTPClient#receiveFile
* receiveFile()} and {@link org.apache.commons.net.tftp.TFTPClient#sendFile sendFile()} methods.
*
*
* @see TFTPPacket
* @see TFTPPacketException
* @see TFTP
*/
public final class TFTPErrorPacket extends TFTPPacket {
/** The undefined error code according to RFC 783, value 0. */
public static final int UNDEFINED = 0;
/** The file not found error code according to RFC 783, value 1. */
public static final int FILE_NOT_FOUND = 1;
/** The access violation error code according to RFC 783, value 2. */
public static final int ACCESS_VIOLATION = 2;
/** The disk full error code according to RFC 783, value 3. */
public static final int OUT_OF_SPACE = 3;
/**
* The illegal TFTP operation error code according to RFC 783, value 4.
*/
public static final int ILLEGAL_OPERATION = 4;
/** The unknown transfer id error code according to RFC 783, value 5. */
public static final int UNKNOWN_TID = 5;
/** The file already exists error code according to RFC 783, value 6. */
public static final int FILE_EXISTS = 6;
/** The no such user error code according to RFC 783, value 7. */
public static final int NO_SUCH_USER = 7;
/** The error code of this packet. */
private final int error;
/** The error message of this packet. */
private final String message;
/**
* Creates an error packet based from a received datagram. Assumes the datagram is at least length 4, else an ArrayIndexOutOfBoundsException may be thrown.
*
* @param datagram The datagram containing the received error.
* @throws TFTPPacketException If the datagram isn't a valid TFTP error packet.
*/
TFTPErrorPacket(final DatagramPacket datagram) throws TFTPPacketException {
super(TFTPPacket.ERROR, datagram.getAddress(), datagram.getPort());
int index;
final int length;
final byte[] data;
final StringBuilder buffer;
data = datagram.getData();
length = datagram.getLength();
if (getType() != data[1]) {
throw new TFTPPacketException("TFTP operator code does not match type.");
}
error = (data[2] & 0xff) << 8 | data[3] & 0xff;
if (length < 5) {
throw new TFTPPacketException("Bad error packet. No message.");
}
index = 4;
buffer = new StringBuilder();
while (index < length && data[index] != 0) {
buffer.append((char) data[index]);
++index;
}
message = buffer.toString();
}
/**
* Creates an error packet to be sent to a host at a given port with an error code and error message.
*
* @param destination The host to which the packet is going to be sent.
* @param port The port to which the packet is going to be sent.
* @param error The error code of the packet.
* @param message The error message of the packet.
*/
public TFTPErrorPacket(final InetAddress destination, final int port, final int error, final String message) {
super(TFTPPacket.ERROR, destination, port);
this.error = error;
this.message = message;
}
/**
* Returns the error code of the packet.
*
* @return The error code of the packet.
*/
public int getError() {
return error;
}
/**
* Returns the error message of the packet.
*
* @return The error message of the packet.
*/
public String getMessage() {
return message;
}
/**
* Creates a UDP datagram containing all the TFTP error packet data in the proper format. This is a method exposed to the programmer in case he wants to
* implement his own TFTP client instead of using the {@link org.apache.commons.net.tftp.TFTPClient} class. Under normal circumstances, you should not have
* a need to call this method.
*
* @return A UDP datagram containing the TFTP error packet.
*/
@Override
public DatagramPacket newDatagram() {
final byte[] data;
final int length;
length = message.length();
data = new byte[length + 5];
data[0] = 0;
data[1] = (byte) type;
data[2] = (byte) ((error & 0xffff) >> 8);
data[3] = (byte) (error & 0xff);
System.arraycopy(message.getBytes(), 0, data, 4, length);
data[length + 4] = 0;
return new DatagramPacket(data, data.length, address, port);
}
/**
* This is a method only available within the package for implementing efficient datagram transport by eliminating buffering. It takes a datagram as an
* 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.
*
* @param datagram The datagram to create.
* @param data The buffer to store the packet and to use in the datagram.
* @return The datagram argument.
*/
@Override
DatagramPacket newDatagram(final DatagramPacket datagram, final byte[] data) {
final int length;
length = message.length();
data[0] = 0;
data[1] = (byte) type;
data[2] = (byte) ((error & 0xffff) >> 8);
data[3] = (byte) (error & 0xff);
System.arraycopy(message.getBytes(), 0, data, 4, length);
data[length + 4] = 0;
datagram.setAddress(address);
datagram.setPort(port);
datagram.setData(data);
datagram.setLength(length + 4);
return datagram;
}
/**
* For debugging
*
* @since 3.6
*/
@Override
public String toString() {
return super.toString() + " ERR " + error + " " + message;
}
}