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1 package org.apache.commons.net; 2 3 /* ==================================================================== 4 * The Apache Software License, Version 1.1 5 * 6 * Copyright (c) 2001 The Apache Software Foundation. All rights 7 * reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in 18 * the documentation and/or other materials provided with the 19 * distribution. 20 * 21 * 3. The end-user documentation included with the redistribution, 22 * if any, must include the following acknowledgment: 23 * "This product includes software developed by the 24 * Apache Software Foundation (http://www.apache.org/)." 25 * Alternately, this acknowledgment may appear in the software itself, 26 * if and wherever such third-party acknowledgments normally appear. 27 * 28 * 4. The names "Apache" and "Apache Software Foundation" and 29 * "Apache Commons" must not be used to endorse or promote products 30 * derived from this software without prior written permission. For 31 * written permission, please contact apache@apache.org. 32 * 33 * 5. Products derived from this software may not be called "Apache", 34 * nor may "Apache" appear in their name, without 35 * prior written permission of the Apache Software Foundation. 36 * 37 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED 38 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 39 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 40 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR 41 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 42 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 43 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 44 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 45 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 46 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 47 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 48 * SUCH DAMAGE. 49 * ==================================================================== 50 * 51 * This software consists of voluntary contributions made by many 52 * individuals on behalf of the Apache Software Foundation. For more 53 * information on the Apache Software Foundation, please see 54 * <http://www.apache.org/>;. 55 */ 56 57 import java.io.IOException; 58 import java.net.DatagramPacket; 59 import java.net.InetAddress; 60 61 /**** 62 * The CharGenUDPClient class is a UDP implementation of a client for the 63 * character generator protocol described in RFC 864. It can also be 64 * used for Systat (RFC 866), Quote of the Day (RFC 865), and netstat 65 * (port 15). All of these protocols involve sending a datagram to the 66 * appropriate port, and reading data contained in one or more reply 67 * datagrams. The chargen and quote of the day protocols only send 68 * one reply datagram containing 512 bytes or less of data. The other 69 * protocols may reply with more than one datagram, in which case you 70 * must wait for a timeout to determine that all reply datagrams have 71 * been sent. 72 * <p> 73 * To use the CharGenUDPClient class, just open a local UDP port 74 * with <a href="org.apache.commons.net.DatagramSocketClient.html#open"> open </a> 75 * and call <a href="#send"> send </a> to send the datagram that will 76 * initiate the data reply. For chargen or quote of the day, just 77 * call <a href="#recieve"> receive </a>, and you're done. For netstat and 78 * systat, call receive in a while loop, and catch a SocketException and 79 * InterruptedIOException to detect a timeout (don't forget to set the 80 * timeout duration beforehand). Don't forget to call 81 * <a href="org.apache.commons.net.DatagramSocketClient.html#close"> close() </a> 82 * to clean up properly. 83 * <p> 84 * <p> 85 * @author Daniel F. Savarese 86 * @see CharGenTCPClient 87 ***/ 88 89 public final class CharGenUDPClient extends DatagramSocketClient 90 { 91 /**** The systat port value of 11 according to RFC 866. ***/ 92 public static final int SYSTAT_PORT = 11; 93 /**** The netstat port value of 19. ***/ 94 public static final int NETSTAT_PORT = 15; 95 /**** The quote of the day port value of 17 according to RFC 865. ***/ 96 public static final int QUOTE_OF_DAY_PORT = 17; 97 /**** The character generator port value of 19 according to RFC 864. ***/ 98 public static final int CHARGEN_PORT = 19; 99 /**** The default chargen port. It is set to 19 according to RFC 864. ***/ 100 public static final int DEFAULT_PORT = 19; 101 102 private byte[] __receiveData; 103 private DatagramPacket __receivePacket; 104 private DatagramPacket __sendPacket; 105 106 /**** 107 * The default CharGenUDPClient constructor. It initializes some internal 108 * data structures for sending and receiving the necessary datagrams for 109 * the chargen and related protocols. 110 ***/ 111 public CharGenUDPClient() 112 { 113 // CharGen return packets have a maximum length of 512 114 __receiveData = new byte[512]; 115 __receivePacket = new DatagramPacket(__receiveData, 512); 116 __sendPacket = new DatagramPacket(new byte[0], 0); 117 } 118 119 120 /**** 121 * Sends the data initiation datagram. This data in the packet is ignored 122 * by the server, and merely serves to signal that the server should send 123 * its reply. 124 * <p> 125 * @param host The address of the server. 126 * @param port The port of the service. 127 * @exception IOException If an error occurs while sending the datagram. 128 ***/ 129 public void send(InetAddress host, int port) throws IOException 130 { 131 __sendPacket.setAddress(host); 132 __sendPacket.setPort(port); 133 _socket_.send(__sendPacket); 134 } 135 136 /**** Same as <code>send(host, CharGenUDPClient.DEFAULT_PORT);</code> ***/ 137 public void send(InetAddress host) throws IOException 138 { 139 send(host, DEFAULT_PORT); 140 } 141 142 /**** 143 * Receive the reply data from the server. This will always be 512 bytes 144 * or less. Chargen and quote of the day only return one packet. Netstat 145 * and systat require multiple calls to receive() with timeout detection. 146 * <p> 147 * @return The reply data from the server. 148 * @exception IOException If an error occurs while receiving the datagram. 149 ***/ 150 public byte[] receive() throws IOException 151 { 152 int length; 153 byte[] result; 154 155 _socket_.receive(__receivePacket); 156 157 result = new byte[length = __receivePacket.getLength()]; 158 System.arraycopy(__receiveData, 0, result, 0, length); 159 160 return result; 161 } 162 163 } 164

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