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Diffstat (limited to 'org/apache/commons/net/tftp/TFTPDataPacket.java')
| -rw-r--r-- | org/apache/commons/net/tftp/TFTPDataPacket.java | 254 |
1 files changed, 254 insertions, 0 deletions
diff --git a/org/apache/commons/net/tftp/TFTPDataPacket.java b/org/apache/commons/net/tftp/TFTPDataPacket.java new file mode 100644 index 0000000..24c0dd3 --- /dev/null +++ b/org/apache/commons/net/tftp/TFTPDataPacket.java @@ -0,0 +1,254 @@ +/*
+ * 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 definiing the TFTP Data
+ * 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.
+ * <p>
+ * <p>
+ * @author Daniel F. Savarese
+ * @see TFTPPacket
+ * @see TFTPPacketException
+ * @see TFTP
+ ***/
+
+public final class TFTPDataPacket extends TFTPPacket
+{
+ /*** The maximum number of bytes in a TFTP data packet (512) ***/
+ public static final int MAX_DATA_LENGTH = 512;
+
+ /*** The minimum number of bytes in a TFTP data packet (0) ***/
+ public static final int MIN_DATA_LENGTH = 0;
+
+ /*** The block number of the packet. ***/
+ int _blockNumber;
+
+ /*** The length of the data. ***/
+ int _length;
+
+ /*** The offset into the _data array at which the data begins. ***/
+ int _offset;
+
+ /*** The data stored in the packet. ***/
+ byte[] _data;
+
+ /***
+ * Creates a data packet to be sent to a host at a given port
+ * with a given block number. The actual data to be sent is passed as
+ * an array, an offset, and a length. The offset is the offset into
+ * the byte array where the data starts. The length is the length of
+ * the data. If the length is greater than MAX_DATA_LENGTH, it is
+ * truncated.
+ * <p>
+ * @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 blockNumber The block number of the data.
+ * @param data The byte array containing the data.
+ * @param offset The offset into the array where the data starts.
+ * @param length The length of the data.
+ ***/
+ public TFTPDataPacket(InetAddress destination, int port, int blockNumber,
+ byte[] data, int offset, int length)
+ {
+ super(TFTPPacket.DATA, destination, port);
+
+ _blockNumber = blockNumber;
+ _data = data;
+ _offset = offset;
+
+ if (length > MAX_DATA_LENGTH)
+ _length = MAX_DATA_LENGTH;
+ else
+ _length = length;
+ }
+
+ public TFTPDataPacket(InetAddress destination, int port, int blockNumber,
+ byte[] data)
+ {
+ this(destination, port, blockNumber, data, 0, data.length);
+ }
+
+
+ /***
+ * Creates a data packet based from a received
+ * datagram. Assumes the datagram is at least length 4, else an
+ * ArrayIndexOutOfBoundsException may be thrown.
+ * <p>
+ * @param datagram The datagram containing the received data.
+ * @throws TFTPPacketException If the datagram isn't a valid TFTP
+ * data packet.
+ ***/
+ TFTPDataPacket(DatagramPacket datagram) throws TFTPPacketException
+ {
+ super(TFTPPacket.DATA, datagram.getAddress(), datagram.getPort());
+
+ _data = datagram.getData();
+ _offset = 4;
+
+ if (getType() != _data[1])
+ throw new TFTPPacketException("TFTP operator code does not match type.");
+
+ _blockNumber = (((_data[2] & 0xff) << 8) | (_data[3] & 0xff));
+
+ _length = datagram.getLength() - 4;
+
+ if (_length > MAX_DATA_LENGTH)
+ _length = MAX_DATA_LENGTH;
+ }
+
+ /***
+ * This is a method only available within the package for
+ * implementing efficient datagram transport by elminating 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.
+ * <p>
+ * @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(DatagramPacket datagram, byte[] data)
+ {
+ data[0] = 0;
+ data[1] = (byte)_type;
+ data[2] = (byte)((_blockNumber & 0xffff) >> 8);
+ data[3] = (byte)(_blockNumber & 0xff);
+
+ // Doublecheck we're not the same
+ if (data != _data)
+ System.arraycopy(_data, _offset, data, 4, _length);
+
+ datagram.setAddress(_address);
+ datagram.setPort(_port);
+ datagram.setData(data);
+ datagram.setLength(_length + 4);
+
+ return datagram;
+ }
+
+ /***
+ * Creates a UDP datagram containing all the TFTP
+ * data 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.
+ * <p>
+ * @return A UDP datagram containing the TFTP data packet.
+ ***/
+ @Override
+ public DatagramPacket newDatagram()
+ {
+ byte[] data;
+
+ data = new byte[_length + 4];
+ data[0] = 0;
+ data[1] = (byte)_type;
+ data[2] = (byte)((_blockNumber & 0xffff) >> 8);
+ data[3] = (byte)(_blockNumber & 0xff);
+
+ System.arraycopy(_data, _offset, data, 4, _length);
+
+ return new DatagramPacket(data, _length + 4, _address, _port);
+ }
+
+ /***
+ * Returns the block number of the data packet.
+ * <p>
+ * @return The block number of the data packet.
+ ***/
+ public int getBlockNumber()
+ {
+ return _blockNumber;
+ }
+
+ /*** Sets the block number of the data packet. ***/
+ public void setBlockNumber(int blockNumber)
+ {
+ _blockNumber = blockNumber;
+ }
+
+ /***
+ * Sets the data for the data packet.
+ * <p>
+ * @param data The byte array containing the data.
+ * @param offset The offset into the array where the data starts.
+ * @param length The length of the data.
+ ***/
+ public void setData(byte[] data, int offset, int length)
+ {
+ _data = data;
+ _offset = offset;
+ _length = length;
+
+ if (length > MAX_DATA_LENGTH)
+ _length = MAX_DATA_LENGTH;
+ else
+ _length = length;
+ }
+
+ /***
+ * Returns the length of the data part of the data packet.
+ * <p>
+ * @return The length of the data part of the data packet.
+ ***/
+ public int getDataLength()
+ {
+ return _length;
+ }
+
+ /***
+ * Returns the offset into the byte array where the packet data actually
+ * starts.
+ * <p>
+ * @return The offset into the byte array where the packet data actually
+ * starts.
+ ***/
+ public int getDataOffset()
+ {
+ return _offset;
+ }
+
+ /***
+ * Returns the byte array containing the packet data.
+ * <p>
+ * @return The byte array containing the packet data.
+ ***/
+ public byte[] getData()
+ {
+ return _data;
+ }
+}
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