J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2003-2004 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. |
| 8 | * |
| 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 12 | * version 2 for more details (a copy is included in the LICENSE file that |
| 13 | * accompanied this code). |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License version |
| 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 18 | * |
| 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 21 | * have any questions. |
| 22 | */ |
| 23 | |
| 24 | /* |
| 25 | * |
| 26 | * |
| 27 | * An "echo" service designed to be used with inetd. It can be configured in |
| 28 | * inetd.conf to be used by any of the following types of services :- |
| 29 | * |
| 30 | * stream tcp nowait |
| 31 | * stream tcp6 nowait |
| 32 | * stream tcp wait |
| 33 | * stream tcp6 wait |
| 34 | * dgram udp wait |
| 35 | * dgram udp6 wait |
| 36 | * |
| 37 | * If configured as a "tcp nowait" service then inetd will launch a |
| 38 | * VM to run the EchoService each time that a client connects to |
| 39 | * the TCP port. The EchoService simply echos any messages it |
| 40 | * receives from the client and shuts if the client closes the |
| 41 | * connection. |
| 42 | * |
| 43 | * If configured as a "tcp wait" service then inetd will launch a VM |
| 44 | * to run the EchoService when a client connects to the port. When |
| 45 | * launched the EchoService takes over the listener socket. It |
| 46 | * terminates when all clients have disconnected and the service |
| 47 | * is idle for a few seconds. |
| 48 | * |
| 49 | * If configured as a "udp wait" service then a VM will be launched for |
| 50 | * each UDP packet to the configured port. System.inheritedChannel() |
| 51 | * will return a DatagramChannel. The echo service here will terminate after |
| 52 | * echoing the UDP packet back to the client. |
| 53 | * |
| 54 | * The service closes the inherited network channel when complete. To |
| 55 | * facilate testing that the channel is closed the "tcp nowait" service |
| 56 | * can close the connection after a given number of bytes. |
| 57 | */ |
| 58 | import java.nio.*; |
| 59 | import java.nio.channels.*; |
| 60 | import java.io.IOException; |
| 61 | import java.net.*; |
| 62 | |
| 63 | public class EchoService { |
| 64 | |
| 65 | private static void doIt(SocketChannel sc, int closeAfter, int delay) throws IOException { |
| 66 | ByteBuffer bb = ByteBuffer.allocate(1024); |
| 67 | int total = 0; |
| 68 | for (;;) { |
| 69 | bb.clear(); |
| 70 | int n = sc.read(bb); |
| 71 | if (n < 0) { |
| 72 | break; |
| 73 | } |
| 74 | total += n; |
| 75 | |
| 76 | // echo |
| 77 | bb.flip(); |
| 78 | sc.write(bb); |
| 79 | |
| 80 | // close after X bytes? |
| 81 | if (closeAfter > 0 && total >= closeAfter) { |
| 82 | break; |
| 83 | } |
| 84 | } |
| 85 | |
| 86 | sc.close(); |
| 87 | if (delay > 0) { |
| 88 | try { |
| 89 | Thread.currentThread().sleep(delay); |
| 90 | } catch (InterruptedException x) { } |
| 91 | } |
| 92 | } |
| 93 | |
| 94 | private static void doIt(DatagramChannel dc) throws IOException { |
| 95 | ByteBuffer bb = ByteBuffer.allocate(1024); |
| 96 | SocketAddress sa = dc.receive(bb); |
| 97 | bb.flip(); |
| 98 | dc.send(bb, sa); |
| 99 | dc.close(); |
| 100 | } |
| 101 | |
| 102 | |
| 103 | // A worker thread to service a single connection |
| 104 | // The class maintains a count of the number of worker threads so |
| 105 | // can the service can terminate then all clients disconnect. |
| 106 | |
| 107 | static class Worker implements Runnable { |
| 108 | private static int count = 0; |
| 109 | private static Object lock = new Object(); |
| 110 | |
| 111 | public static int count() { |
| 112 | synchronized (lock) { |
| 113 | return count; |
| 114 | } |
| 115 | } |
| 116 | |
| 117 | private SocketChannel sc; |
| 118 | |
| 119 | Worker(SocketChannel sc) { |
| 120 | this.sc = sc; |
| 121 | synchronized (lock) { |
| 122 | count++; |
| 123 | } |
| 124 | } |
| 125 | |
| 126 | public void run() { |
| 127 | try { |
| 128 | doIt(sc, -1, -1); |
| 129 | } catch (IOException x) { |
| 130 | } finally { |
| 131 | synchronized (lock) { |
| 132 | count--; |
| 133 | } |
| 134 | } |
| 135 | |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | public static void main(String args[]) throws IOException { |
| 140 | Channel c = System.inheritedChannel(); |
| 141 | if (c == null) { |
| 142 | return; |
| 143 | } |
| 144 | |
| 145 | // tcp nowait |
| 146 | if (c instanceof SocketChannel) { |
| 147 | int closeAfter = 0; |
| 148 | int delay = 0; |
| 149 | if (args.length > 0) { |
| 150 | closeAfter = Integer.parseInt(args[0]); |
| 151 | } |
| 152 | if (args.length > 1) { |
| 153 | delay = Integer.parseInt(args[1]); |
| 154 | } |
| 155 | doIt((SocketChannel)c, closeAfter, delay); |
| 156 | } |
| 157 | |
| 158 | // tcp wait - in this case we take over the listener socket |
| 159 | // In this test case we create a thread to service each connection |
| 160 | // and terminate after all clients are gone. |
| 161 | // |
| 162 | if (c instanceof ServerSocketChannel) { |
| 163 | ServerSocketChannel ssc = (ServerSocketChannel)c; |
| 164 | |
| 165 | ssc.configureBlocking(false); |
| 166 | Selector sel = ssc.provider().openSelector(); |
| 167 | SelectionKey sk = ssc.register(sel, SelectionKey.OP_ACCEPT); |
| 168 | SocketChannel sc; |
| 169 | int count = 0; |
| 170 | for (;;) { |
| 171 | sel.select(5000); |
| 172 | if (sk.isAcceptable() && ((sc = ssc.accept()) != null)) { |
| 173 | Worker w = new Worker(sc); |
| 174 | (new Thread(w)).start(); |
| 175 | } else { |
| 176 | // if all clients have disconnected then we die as well. |
| 177 | if (Worker.count() == 0) { |
| 178 | break; |
| 179 | } |
| 180 | } |
| 181 | } |
| 182 | ssc.close(); |
| 183 | } |
| 184 | |
| 185 | // udp wait |
| 186 | if (c instanceof DatagramChannel) { |
| 187 | doIt((DatagramChannel)c); |
| 188 | } |
| 189 | |
| 190 | // linger? |
| 191 | if (args.length > 0) { |
| 192 | int delay = Integer.parseInt(args[0]); |
| 193 | try { |
| 194 | Thread.currentThread().sleep(delay); |
| 195 | } catch (InterruptedException x) { } |
| 196 | } |
| 197 | |
| 198 | } |
| 199 | |
| 200 | } |