1/* 2 * Copyright (c) 1995, 2016, Oracle and/or its affiliates. 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. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26package java.net; 27 28import java.io.IOException; 29import java.io.InputStream; 30import java.io.OutputStream; 31import java.io.FileDescriptor; 32import java.util.Set; 33 34/** 35 * The abstract class {@code SocketImpl} is a common superclass 36 * of all classes that actually implement sockets. It is used to 37 * create both client and server sockets. 38 * <p> 39 * A "plain" socket implements these methods exactly as 40 * described, without attempting to go through a firewall or proxy. 41 * 42 * @author unascribed 43 * @since 1.0 44 */ 45public abstract class SocketImpl implements SocketOptions { 46 /** 47 * The actual Socket object. 48 */ 49 Socket socket = null; 50 ServerSocket serverSocket = null; 51 52 /** 53 * The file descriptor object for this socket. 54 */ 55 protected FileDescriptor fd; 56 57 /** 58 * The IP address of the remote end of this socket. 59 */ 60 protected InetAddress address; 61 62 /** 63 * The port number on the remote host to which this socket is connected. 64 */ 65 protected int port; 66 67 /** 68 * The local port number to which this socket is connected. 69 */ 70 protected int localport; 71 72 /** 73 * Creates either a stream or a datagram socket. 74 * 75 * @param stream if {@code true}, create a stream socket; 76 * otherwise, create a datagram socket. 77 * @exception IOException if an I/O error occurs while creating the 78 * socket. 79 */ 80 protected abstract void create(boolean stream) throws IOException; 81 82 /** 83 * Connects this socket to the specified port on the named host. 84 * 85 * @param host the name of the remote host. 86 * @param port the port number. 87 * @exception IOException if an I/O error occurs when connecting to the 88 * remote host. 89 */ 90 protected abstract void connect(String host, int port) throws IOException; 91 92 /** 93 * Connects this socket to the specified port number on the specified host. 94 * 95 * @param address the IP address of the remote host. 96 * @param port the port number. 97 * @exception IOException if an I/O error occurs when attempting a 98 * connection. 99 */ 100 protected abstract void connect(InetAddress address, int port) throws IOException; 101 102 /** 103 * Connects this socket to the specified port number on the specified host. 104 * A timeout of zero is interpreted as an infinite timeout. The connection 105 * will then block until established or an error occurs. 106 * 107 * @param address the Socket address of the remote host. 108 * @param timeout the timeout value, in milliseconds, or zero for no timeout. 109 * @exception IOException if an I/O error occurs when attempting a 110 * connection. 111 * @since 1.4 112 */ 113 protected abstract void connect(SocketAddress address, int timeout) throws IOException; 114 115 /** 116 * Binds this socket to the specified local IP address and port number. 117 * 118 * @param host an IP address that belongs to a local interface. 119 * @param port the port number. 120 * @exception IOException if an I/O error occurs when binding this socket. 121 */ 122 protected abstract void bind(InetAddress host, int port) throws IOException; 123 124 /** 125 * Sets the maximum queue length for incoming connection indications 126 * (a request to connect) to the {@code count} argument. If a 127 * connection indication arrives when the queue is full, the 128 * connection is refused. 129 * 130 * @param backlog the maximum length of the queue. 131 * @exception IOException if an I/O error occurs when creating the queue. 132 */ 133 protected abstract void listen(int backlog) throws IOException; 134 135 /** 136 * Accepts a connection. 137 * 138 * @param s the accepted connection. 139 * @exception IOException if an I/O error occurs when accepting the 140 * connection. 141 */ 142 protected abstract void accept(SocketImpl s) throws IOException; 143 144 /** 145 * Returns an input stream for this socket. 146 * 147 * @return a stream for reading from this socket. 148 * @exception IOException if an I/O error occurs when creating the 149 * input stream. 150 */ 151 protected abstract InputStream getInputStream() throws IOException; 152 153 /** 154 * Returns an output stream for this socket. 155 * 156 * @return an output stream for writing to this socket. 157 * @exception IOException if an I/O error occurs when creating the 158 * output stream. 159 */ 160 protected abstract OutputStream getOutputStream() throws IOException; 161 162 /** 163 * Returns the number of bytes that can be read from this socket 164 * without blocking. 165 * 166 * @return the number of bytes that can be read from this socket 167 * without blocking. 168 * @exception IOException if an I/O error occurs when determining the 169 * number of bytes available. 170 */ 171 protected abstract int available() throws IOException; 172 173 /** 174 * Closes this socket. 175 * 176 * @exception IOException if an I/O error occurs when closing this socket. 177 */ 178 protected abstract void close() throws IOException; 179 180 /** 181 * Places the input stream for this socket at "end of stream". 182 * Any data sent to this socket is acknowledged and then 183 * silently discarded. 184 * 185 * If you read from a socket input stream after invoking this method on the 186 * socket, the stream's {@code available} method will return 0, and its 187 * {@code read} methods will return {@code -1} (end of stream). 188 * 189 * @exception IOException if an I/O error occurs when shutting down this 190 * socket. 191 * @see java.net.Socket#shutdownOutput() 192 * @see java.net.Socket#close() 193 * @see java.net.Socket#setSoLinger(boolean, int) 194 * @since 1.3 195 */ 196 protected void shutdownInput() throws IOException { 197 throw new IOException("Method not implemented!"); 198 } 199 200 /** 201 * Disables the output stream for this socket. 202 * For a TCP socket, any previously written data will be sent 203 * followed by TCP's normal connection termination sequence. 204 * 205 * If you write to a socket output stream after invoking 206 * shutdownOutput() on the socket, the stream will throw 207 * an IOException. 208 * 209 * @exception IOException if an I/O error occurs when shutting down this 210 * socket. 211 * @see java.net.Socket#shutdownInput() 212 * @see java.net.Socket#close() 213 * @see java.net.Socket#setSoLinger(boolean, int) 214 * @since 1.3 215 */ 216 protected void shutdownOutput() throws IOException { 217 throw new IOException("Method not implemented!"); 218 } 219 220 /** 221 * Returns the value of this socket's {@code fd} field. 222 * 223 * @return the value of this socket's {@code fd} field. 224 * @see java.net.SocketImpl#fd 225 */ 226 protected FileDescriptor getFileDescriptor() { 227 return fd; 228 } 229 230 /** 231 * Returns the value of this socket's {@code address} field. 232 * 233 * @return the value of this socket's {@code address} field. 234 * @see java.net.SocketImpl#address 235 */ 236 protected InetAddress getInetAddress() { 237 return address; 238 } 239 240 /** 241 * Returns the value of this socket's {@code port} field. 242 * 243 * @return the value of this socket's {@code port} field. 244 * @see java.net.SocketImpl#port 245 */ 246 protected int getPort() { 247 return port; 248 } 249 250 /** 251 * Returns whether or not this SocketImpl supports sending 252 * urgent data. By default, false is returned 253 * unless the method is overridden in a sub-class 254 * 255 * @return true if urgent data supported 256 * @see java.net.SocketImpl#address 257 * @since 1.4 258 */ 259 protected boolean supportsUrgentData () { 260 return false; // must be overridden in sub-class 261 } 262 263 /** 264 * Send one byte of urgent data on the socket. 265 * The byte to be sent is the low eight bits of the parameter 266 * @param data The byte of data to send 267 * @exception IOException if there is an error 268 * sending the data. 269 * @since 1.4 270 */ 271 protected abstract void sendUrgentData (int data) throws IOException; 272 273 /** 274 * Returns the value of this socket's {@code localport} field. 275 * 276 * @return the value of this socket's {@code localport} field. 277 * @see java.net.SocketImpl#localport 278 */ 279 protected int getLocalPort() { 280 return localport; 281 } 282 283 void setSocket(Socket soc) { 284 this.socket = soc; 285 } 286 287 Socket getSocket() { 288 return socket; 289 } 290 291 void setServerSocket(ServerSocket soc) { 292 this.serverSocket = soc; 293 } 294 295 ServerSocket getServerSocket() { 296 return serverSocket; 297 } 298 299 /** 300 * Returns the address and port of this socket as a {@code String}. 301 * 302 * @return a string representation of this socket. 303 */ 304 public String toString() { 305 return "Socket[addr=" + getInetAddress() + 306 ",port=" + getPort() + ",localport=" + getLocalPort() + "]"; 307 } 308 309 void reset() throws IOException { 310 address = null; 311 port = 0; 312 localport = 0; 313 } 314 315 /** 316 * Sets performance preferences for this socket. 317 * 318 * <p> Sockets use the TCP/IP protocol by default. Some implementations 319 * may offer alternative protocols which have different performance 320 * characteristics than TCP/IP. This method allows the application to 321 * express its own preferences as to how these tradeoffs should be made 322 * when the implementation chooses from the available protocols. 323 * 324 * <p> Performance preferences are described by three integers 325 * whose values indicate the relative importance of short connection time, 326 * low latency, and high bandwidth. The absolute values of the integers 327 * are irrelevant; in order to choose a protocol the values are simply 328 * compared, with larger values indicating stronger preferences. Negative 329 * values represent a lower priority than positive values. If the 330 * application prefers short connection time over both low latency and high 331 * bandwidth, for example, then it could invoke this method with the values 332 * {@code (1, 0, 0)}. If the application prefers high bandwidth above low 333 * latency, and low latency above short connection time, then it could 334 * invoke this method with the values {@code (0, 1, 2)}. 335 * 336 * By default, this method does nothing, unless it is overridden in a 337 * a sub-class. 338 * 339 * @param connectionTime 340 * An {@code int} expressing the relative importance of a short 341 * connection time 342 * 343 * @param latency 344 * An {@code int} expressing the relative importance of low 345 * latency 346 * 347 * @param bandwidth 348 * An {@code int} expressing the relative importance of high 349 * bandwidth 350 * 351 * @since 1.5 352 */ 353 protected void setPerformancePreferences(int connectionTime, 354 int latency, 355 int bandwidth) 356 { 357 /* Not implemented yet */ 358 } 359 360 /** 361 * Called to set a socket option. 362 * 363 * @param <T> The type of the socket option value 364 * @param name The socket option 365 * 366 * @param value The value of the socket option. A value of {@code null} 367 * may be valid for some options. 368 * 369 * @throws UnsupportedOperationException if the SocketImpl does not 370 * support the option 371 * 372 * @throws IOException if an I/O error occurs, or if the socket is closed. 373 * 374 * @since 9 375 */ 376 protected <T> void setOption(SocketOption<T> name, T value) throws IOException { 377 if (name == StandardSocketOptions.SO_KEEPALIVE && 378 (getSocket() != null)) { 379 setOption(SocketOptions.SO_KEEPALIVE, value); 380 } else if (name == StandardSocketOptions.SO_SNDBUF && 381 (getSocket() != null)) { 382 setOption(SocketOptions.SO_SNDBUF, value); 383 } else if (name == StandardSocketOptions.SO_RCVBUF) { 384 setOption(SocketOptions.SO_RCVBUF, value); 385 } else if (name == StandardSocketOptions.SO_REUSEADDR) { 386 setOption(SocketOptions.SO_REUSEADDR, value); 387 } else if (name == StandardSocketOptions.SO_REUSEPORT && 388 supportedOptions().contains(name)) { 389 setOption(SocketOptions.SO_REUSEPORT, value); 390 } else if (name == StandardSocketOptions.SO_LINGER && 391 (getSocket() != null)) { 392 setOption(SocketOptions.SO_LINGER, value); 393 } else if (name == StandardSocketOptions.IP_TOS) { 394 setOption(SocketOptions.IP_TOS, value); 395 } else if (name == StandardSocketOptions.TCP_NODELAY && 396 (getSocket() != null)) { 397 setOption(SocketOptions.TCP_NODELAY, value); 398 } else { 399 throw new UnsupportedOperationException("unsupported option"); 400 } 401 } 402 403 /** 404 * Called to get a socket option. 405 * 406 * @param <T> The type of the socket option value 407 * @param name The socket option 408 * 409 * @return the value of the named option 410 * 411 * @throws UnsupportedOperationException if the SocketImpl does not 412 * support the option. 413 * 414 * @throws IOException if an I/O error occurs, or if the socket is closed. 415 * 416 * @since 9 417 */ 418 @SuppressWarnings("unchecked") 419 protected <T> T getOption(SocketOption<T> name) throws IOException { 420 if (name == StandardSocketOptions.SO_KEEPALIVE && 421 (getSocket() != null)) { 422 return (T)getOption(SocketOptions.SO_KEEPALIVE); 423 } else if (name == StandardSocketOptions.SO_SNDBUF && 424 (getSocket() != null)) { 425 return (T)getOption(SocketOptions.SO_SNDBUF); 426 } else if (name == StandardSocketOptions.SO_RCVBUF) { 427 return (T)getOption(SocketOptions.SO_RCVBUF); 428 } else if (name == StandardSocketOptions.SO_REUSEADDR) { 429 return (T)getOption(SocketOptions.SO_REUSEADDR); 430 } else if (name == StandardSocketOptions.SO_REUSEPORT && 431 supportedOptions().contains(name)) { 432 return (T)getOption(SocketOptions.SO_REUSEPORT); 433 } else if (name == StandardSocketOptions.SO_LINGER && 434 (getSocket() != null)) { 435 return (T)getOption(SocketOptions.SO_LINGER); 436 } else if (name == StandardSocketOptions.IP_TOS) { 437 return (T)getOption(SocketOptions.IP_TOS); 438 } else if (name == StandardSocketOptions.TCP_NODELAY && 439 (getSocket() != null)) { 440 return (T)getOption(SocketOptions.TCP_NODELAY); 441 } else { 442 throw new UnsupportedOperationException("unsupported option"); 443 } 444 } 445 446 private static final Set<SocketOption<?>> socketOptions; 447 448 private static final Set<SocketOption<?>> serverSocketOptions; 449 450 static { 451 socketOptions = Set.of(StandardSocketOptions.SO_KEEPALIVE, 452 StandardSocketOptions.SO_SNDBUF, 453 StandardSocketOptions.SO_RCVBUF, 454 StandardSocketOptions.SO_REUSEADDR, 455 StandardSocketOptions.SO_LINGER, 456 StandardSocketOptions.IP_TOS, 457 StandardSocketOptions.TCP_NODELAY); 458 459 serverSocketOptions = Set.of(StandardSocketOptions.SO_RCVBUF, 460 StandardSocketOptions.SO_REUSEADDR, 461 StandardSocketOptions.IP_TOS); 462 } 463 464 /** 465 * Returns a set of SocketOptions supported by this impl 466 * and by this impl's socket (Socket or ServerSocket) 467 * 468 * @return a Set of SocketOptions 469 * 470 * @since 9 471 */ 472 protected Set<SocketOption<?>> supportedOptions() { 473 if (getSocket() != null) { 474 return socketOptions; 475 } else { 476 return serverSocketOptions; 477 } 478 } 479} 480