    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
    018    package org.apache.commons.net.tftp;
    019
    020    import java.net.DatagramPacket;
    021    import java.net.InetAddress;
    022
    023    /***
    024     * A final class derived from TFTPPacket definiing the TFTP Error
    025     * packet type.
    026     * <p>
    027     * Details regarding the TFTP protocol and the format of TFTP packets can
    028     * be found in RFC 783.  But the point of these classes is to keep you
    029     * from having to worry about the internals.  Additionally, only very
    030     * few people should have to care about any of the TFTPPacket classes
    031     * or derived classes.  Almost all users should only be concerned with the
    032     * {@link org.apache.commons.net.tftp.TFTPClient} class
    033     * {@link org.apache.commons.net.tftp.TFTPClient#receiveFile receiveFile()}
    034     * and
    035     * {@link org.apache.commons.net.tftp.TFTPClient#sendFile sendFile()}
    036     * methods.
    037     * <p>
    038     * <p>
    039     * @author Daniel F. Savarese
    040     * @see TFTPPacket
    041     * @see TFTPPacketException
    042     * @see TFTP
    043     ***/
    044
    045    public final class TFTPErrorPacket extends TFTPPacket
    046    {
    047        /*** The undefined error code according to RFC 783, value 0. ***/
    048        public static final int UNDEFINED = 0;
    049
    050        /*** The file not found error code according to RFC 783, value 1. ***/
    051        public static final int FILE_NOT_FOUND = 1;
    052
    053        /*** The access violation error code according to RFC 783, value 2. ***/
    054        public static final int ACCESS_VIOLATION = 2;
    055
    056        /*** The disk full error code according to RFC 783, value 3. ***/
    057        public static final int OUT_OF_SPACE = 3;
    058
    059        /***
    060         * The illegal TFTP operation error code according to RFC 783, value 4.
    061         ***/
    062        public static final int ILLEGAL_OPERATION = 4;
    063
    064        /*** The unknown transfer id error code according to RFC 783, value 5. ***/
    065        public static final int UNKNOWN_TID = 5;
    066
    067        /*** The file already exists error code according to RFC 783, value 6. ***/
    068        public static final int FILE_EXISTS = 6;
    069
    070        /*** The no such user error code according to RFC 783, value 7. ***/
    071        public static final int NO_SUCH_USER = 7;
    072
    073        /*** The error code of this packet. ***/
    074        int _error;
    075
    076        /*** The error message of this packet. ***/
    077        String _message;
    078
    079        /***
    080         * Creates an error packet to be sent to a host at a given port
    081         * with an error code and error message.
    082         * <p>
    083         * @param destination  The host to which the packet is going to be sent.
    084         * @param port  The port to which the packet is going to be sent.
    085         * @param error The error code of the packet.
    086         * @param message The error message of the packet.
    087         ***/
    088        public TFTPErrorPacket(InetAddress destination, int port,
    089                               int error, String message)
    090        {
    091            super(TFTPPacket.ERROR, destination, port);
    092
    093            _error = error;
    094            _message = message;
    095        }
    096
    097        /***
    098         * Creates an error packet based from a received
    099         * datagram.  Assumes the datagram is at least length 4, else an
    100         * ArrayIndexOutOfBoundsException may be thrown.
    101         * <p>
    102         * @param datagram  The datagram containing the received error.
    103         * @throws TFTPPacketException  If the datagram isn't a valid TFTP
    104         *         error packet.
    105         ***/
    106        TFTPErrorPacket(DatagramPacket datagram) throws TFTPPacketException
    107        {
    108            super(TFTPPacket.ERROR, datagram.getAddress(), datagram.getPort());
    109            int index, length;
    110            byte[] data;
    111            StringBuilder buffer;
    112
    113            data = datagram.getData();
    114            length = datagram.getLength();
    115
    116            if (getType() != data[1])
    117                throw new TFTPPacketException("TFTP operator code does not match type.");
    118
    119            _error = (((data[2] & 0xff) << 8) | (data[3] & 0xff));
    120
    121            if (length < 5)
    122                throw new TFTPPacketException("Bad error packet. No message.");
    123
    124            index = 4;
    125            buffer = new StringBuilder();
    126
    127            while (index < length && data[index] != 0)
    128            {
    129                buffer.append((char)data[index]);
    130                ++index;
    131            }
    132
    133            _message = buffer.toString();
    134        }
    135
    136        /***
    137         * This is a method only available within the package for
    138         * implementing efficient datagram transport by elminating buffering.
    139         * It takes a datagram as an argument, and a byte buffer in which
    140         * to store the raw datagram data.  Inside the method, the data
    141         * is set as the datagram's data and the datagram returned.
    142         * <p>
    143         * @param datagram  The datagram to create.
    144         * @param data The buffer to store the packet and to use in the datagram.
    145         * @return The datagram argument.
    146         ***/
    147        @Override
    148        DatagramPacket _newDatagram(DatagramPacket datagram, byte[] data)
    149        {
    150            int length;
    151
    152            length = _message.length();
    153
    154            data[0] = 0;
    155            data[1] = (byte)_type;
    156            data[2] = (byte)((_error & 0xffff) >> 8);
    157            data[3] = (byte)(_error & 0xff);
    158
    159            System.arraycopy(_message.getBytes(), 0, data, 4, length);
    160
    161            data[length + 4] = 0;
    162
    163            datagram.setAddress(_address);
    164            datagram.setPort(_port);
    165            datagram.setData(data);
    166            datagram.setLength(length + 4);
    167
    168            return datagram;
    169        }
    170
    171
    172        /***
    173         * Creates a UDP datagram containing all the TFTP
    174         * error packet data in the proper format.
    175         * This is a method exposed to the programmer in case he
    176         * wants to implement his own TFTP client instead of using
    177         * the {@link org.apache.commons.net.tftp.TFTPClient}
    178         * class.
    179         * Under normal circumstances, you should not have a need to call this
    180         * method.
    181         * <p>
    182         * @return A UDP datagram containing the TFTP error packet.
    183         ***/
    184        @Override
    185        public DatagramPacket newDatagram()
    186        {
    187            byte[] data;
    188            int length;
    189
    190            length = _message.length();
    191
    192            data = new byte[length + 5];
    193            data[0] = 0;
    194            data[1] = (byte)_type;
    195            data[2] = (byte)((_error & 0xffff) >> 8);
    196            data[3] = (byte)(_error & 0xff);
    197
    198            System.arraycopy(_message.getBytes(), 0, data, 4, length);
    199
    200            data[length + 4] = 0;
    201
    202            return new DatagramPacket(data, data.length, _address, _port);
    203        }
    204
    205
    206        /***
    207         * Returns the error code of the packet.
    208         * <p>
    209         * @return The error code of the packet.
    210         ***/
    211        public int getError()
    212        {
    213            return _error;
    214        }
    215
    216
    217        /***
    218         * Returns the error message of the packet.
    219         * <p>
    220         * @return The error message of the packet.
    221         ***/
    222        public String getMessage()
    223        {
    224            return _message;
    225        }
    226    }