diff options
Diffstat (limited to 'org/apache/commons/net/tftp/TFTPPacket.java')
| -rw-r--r-- | org/apache/commons/net/tftp/TFTPPacket.java | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/org/apache/commons/net/tftp/TFTPPacket.java b/org/apache/commons/net/tftp/TFTPPacket.java new file mode 100644 index 0000000..e1dc5f1 --- /dev/null +++ b/org/apache/commons/net/tftp/TFTPPacket.java @@ -0,0 +1,247 @@ +/*
+ * 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;
+
+/***
+ * TFTPPacket is an abstract class encapsulating the functionality common
+ * to the 5 types of TFTP packets. It also provides a static factory
+ * method that will create the correct TFTP packet instance from a
+ * datagram. This relieves the programmer from having to figure out what
+ * kind of TFTP packet is contained in a datagram and create it himself.
+ * <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 TFTPPacketException
+ * @see TFTP
+ ***/
+
+public abstract class TFTPPacket
+{
+ /***
+ * The minimum size of a packet. This is 4 bytes. It is enough
+ * to store the opcode and blocknumber or other required data
+ * depending on the packet type.
+ ***/
+ static final int MIN_PACKET_SIZE = 4;
+
+ /***
+ * This is the actual TFTP spec
+ * identifier and is equal to 1.
+ * Identifier returned by {@link #getType getType()}
+ * indicating a read request packet.
+ ***/
+ public static final int READ_REQUEST = 1;
+
+ /***
+ * This is the actual TFTP spec
+ * identifier and is equal to 2.
+ * Identifier returned by {@link #getType getType()}
+ * indicating a write request packet.
+ ***/
+ public static final int WRITE_REQUEST = 2;
+
+ /***
+ * This is the actual TFTP spec
+ * identifier and is equal to 3.
+ * Identifier returned by {@link #getType getType()}
+ * indicating a data packet.
+ ***/
+ public static final int DATA = 3;
+
+ /***
+ * This is the actual TFTP spec
+ * identifier and is equal to 4.
+ * Identifier returned by {@link #getType getType()}
+ * indicating an acknowledgement packet.
+ ***/
+ public static final int ACKNOWLEDGEMENT = 4;
+
+ /***
+ * This is the actual TFTP spec
+ * identifier and is equal to 5.
+ * Identifier returned by {@link #getType getType()}
+ * indicating an error packet.
+ ***/
+ public static final int ERROR = 5;
+
+ /***
+ * The TFTP data packet maximum segment size in bytes. This is 512
+ * and is useful for those familiar with the TFTP protocol who want
+ * to use the {@link org.apache.commons.net.tftp.TFTP}
+ * class methods to implement their own TFTP servers or clients.
+ ***/
+ public static final int SEGMENT_SIZE = 512;
+
+ /*** The type of packet. ***/
+ int _type;
+
+ /*** The port the packet came from or is going to. ***/
+ int _port;
+
+ /*** The host the packet is going to be sent or where it came from. ***/
+ InetAddress _address;
+
+ /***
+ * When you receive a datagram that you expect to be a TFTP packet, you use
+ * this factory method to create the proper TFTPPacket object
+ * encapsulating the data contained in that datagram. This method is the
+ * only way you can instantiate a TFTPPacket derived class from a
+ * datagram.
+ * <p>
+ * @param datagram The datagram containing a TFTP packet.
+ * @return The TFTPPacket object corresponding to the datagram.
+ * @exception TFTPPacketException If the datagram does not contain a valid
+ * TFTP packet.
+ ***/
+ public final static TFTPPacket newTFTPPacket(DatagramPacket datagram)
+ throws TFTPPacketException
+ {
+ byte[] data;
+ TFTPPacket packet = null;
+
+ if (datagram.getLength() < MIN_PACKET_SIZE)
+ throw new TFTPPacketException(
+ "Bad packet. Datagram data length is too short.");
+
+ data = datagram.getData();
+
+ switch (data[1])
+ {
+ case READ_REQUEST:
+ packet = new TFTPReadRequestPacket(datagram);
+ break;
+ case WRITE_REQUEST:
+ packet = new TFTPWriteRequestPacket(datagram);
+ break;
+ case DATA:
+ packet = new TFTPDataPacket(datagram);
+ break;
+ case ACKNOWLEDGEMENT:
+ packet = new TFTPAckPacket(datagram);
+ break;
+ case ERROR:
+ packet = new TFTPErrorPacket(datagram);
+ break;
+ default:
+ throw new TFTPPacketException(
+ "Bad packet. Invalid TFTP operator code.");
+ }
+
+ return packet;
+ }
+
+ /***
+ * This constructor is not visible outside of the package. It is used
+ * by subclasses within the package to initialize base data.
+ * <p>
+ * @param type The type of the packet.
+ * @param address The host the packet came from or is going to be sent.
+ * @param port The port the packet came from or is going to be sent.
+ **/
+ TFTPPacket(int type, InetAddress address, int port)
+ {
+ _type = type;
+ _address = address;
+ _port = port;
+ }
+
+ /***
+ * This is an abstract 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
+ * should be 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.
+ ***/
+ abstract DatagramPacket _newDatagram(DatagramPacket datagram, byte[] data);
+
+ /***
+ * Creates a UDP datagram containing all the TFTP packet
+ * data in the proper format.
+ * This is an abstract 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 packet.
+ ***/
+ public abstract DatagramPacket newDatagram();
+
+ /***
+ * Returns the type of the packet.
+ * <p>
+ * @return The type of the packet.
+ ***/
+ public final int getType()
+ {
+ return _type;
+ }
+
+ /***
+ * Returns the address of the host where the packet is going to be sent
+ * or where it came from.
+ * <p>
+ * @return The type of the packet.
+ ***/
+ public final InetAddress getAddress()
+ {
+ return _address;
+ }
+
+ /***
+ * Returns the port where the packet is going to be sent
+ * or where it came from.
+ * <p>
+ * @return The port where the packet came from or where it is going.
+ ***/
+ public final int getPort()
+ {
+ return _port;
+ }
+
+ /*** Sets the port where the packet is going to be sent. ***/
+ public final void setPort(int port)
+ {
+ _port = port;
+ }
+
+ /*** Sets the host address where the packet is going to be sent. ***/
+ public final void setAddress(InetAddress address)
+ {
+ _address = address;
+ }
+}
|