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
26 package java.net;
27
28 import java.io.IOException;
29 import java.io.InputStream;
30 import java.io.OutputStream;
31 import java.io.FileDescriptor;
32 import 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 */
45 public 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 /**
284 * Set the Socket object
285 * @param soc the socket
286 */
287 protected void setSocket(Socket soc) {
288 this.socket = soc;
289 }
290
291 Socket getSocket() {
292 return socket;
293 }
294
295 /**
296 * Set the ServerSocket object
297 * @param soc the socket
298 */
299 protected void setServerSocket(ServerSocket soc) {
300 this.serverSocket = soc;
301 }
302
303 ServerSocket getServerSocket() {
304 return serverSocket;
305 }
306
307 /**
308 * Returns the address and port of this socket as a {@code String}.
309 *
310 * @return a string representation of this socket.
311 */
312 public String toString() {
313 return "Socket[addr=" + getInetAddress() +
314 ",port=" + getPort() + ",localport=" + getLocalPort() + "]";
315 }
316
317 void reset() throws IOException {
318 address = null;
319 port = 0;
320 localport = 0;
321 }
322
323 /**
324 * Sets performance preferences for this socket.
325 *
326 * <p> Sockets use the TCP/IP protocol by default. Some implementations
327 * may offer alternative protocols which have different performance
328 * characteristics than TCP/IP. This method allows the application to
329 * express its own preferences as to how these tradeoffs should be made
330 * when the implementation chooses from the available protocols.
331 *
332 * <p> Performance preferences are described by three integers
333 * whose values indicate the relative importance of short connection time,
334 * low latency, and high bandwidth. The absolute values of the integers
335 * are irrelevant; in order to choose a protocol the values are simply
336 * compared, with larger values indicating stronger preferences. Negative
337 * values represent a lower priority than positive values. If the
338 * application prefers short connection time over both low latency and high
339 * bandwidth, for example, then it could invoke this method with the values
340 * {@code (1, 0, 0)}. If the application prefers high bandwidth above low
341 * latency, and low latency above short connection time, then it could
342 * invoke this method with the values {@code (0, 1, 2)}.
343 *
344 * By default, this method does nothing, unless it is overridden in
345 * a sub-class.
346 *
347 * @param connectionTime
348 * An {@code int} expressing the relative importance of a short
349 * connection time
350 *
351 * @param latency
352 * An {@code int} expressing the relative importance of low
353 * latency
354 *
355 * @param bandwidth
356 * An {@code int} expressing the relative importance of high
357 * bandwidth
358 *
359 * @since 1.5
360 */
361 protected void setPerformancePreferences(int connectionTime,
362 int latency,
363 int bandwidth)
364 {
365 /* Not implemented yet */
366 }
367
368 /**
369 * Called to set a socket option.
370 *
371 * @param <T> The type of the socket option value
372 * @param name The socket option
373 *
374 * @param value The value of the socket option. A value of {@code null}
375 * may be valid for some options.
376 *
377 * @throws UnsupportedOperationException if the SocketImpl does not
378 * support the option
379 *
380 * @throws IOException if an I/O error occurs, or if the socket is closed.
381 *
382 * @since 9
383 */
384 protected <T> void setOption(SocketOption<T> name, T value) throws IOException {
385 if (name == StandardSocketOptions.SO_KEEPALIVE &&
386 (getSocket() != null)) {
387 setOption(SocketOptions.SO_KEEPALIVE, value);
388 } else if (name == StandardSocketOptions.SO_SNDBUF &&
389 (getSocket() != null)) {
390 setOption(SocketOptions.SO_SNDBUF, value);
391 } else if (name == StandardSocketOptions.SO_RCVBUF) {
392 setOption(SocketOptions.SO_RCVBUF, value);
393 } else if (name == StandardSocketOptions.SO_REUSEADDR) {
394 setOption(SocketOptions.SO_REUSEADDR, value);
395 } else if (name == StandardSocketOptions.SO_REUSEPORT &&
396 supportedOptions().contains(name)) {
397 setOption(SocketOptions.SO_REUSEPORT, value);
398 } else if (name == StandardSocketOptions.SO_LINGER &&
399 (getSocket() != null)) {
400 setOption(SocketOptions.SO_LINGER, value);
401 } else if (name == StandardSocketOptions.IP_TOS) {
402 setOption(SocketOptions.IP_TOS, value);
403 } else if (name == StandardSocketOptions.TCP_NODELAY &&
404 (getSocket() != null)) {
405 setOption(SocketOptions.TCP_NODELAY, value);
406 } else {
407 throw new UnsupportedOperationException("unsupported option");
408 }
409 }
410
411 /**
412 * Called to get a socket option.
413 *
414 * @param <T> The type of the socket option value
415 * @param name The socket option
416 *
417 * @return the value of the named option
418 *
419 * @throws UnsupportedOperationException if the SocketImpl does not
420 * support the option.
421 *
422 * @throws IOException if an I/O error occurs, or if the socket is closed.
423 *
424 * @since 9
425 */
426 @SuppressWarnings("unchecked")
427 protected <T> T getOption(SocketOption<T> name) throws IOException {
428 if (name == StandardSocketOptions.SO_KEEPALIVE &&
429 (getSocket() != null)) {
430 return (T)getOption(SocketOptions.SO_KEEPALIVE);
431 } else if (name == StandardSocketOptions.SO_SNDBUF &&
432 (getSocket() != null)) {
433 return (T)getOption(SocketOptions.SO_SNDBUF);
434 } else if (name == StandardSocketOptions.SO_RCVBUF) {
435 return (T)getOption(SocketOptions.SO_RCVBUF);
436 } else if (name == StandardSocketOptions.SO_REUSEADDR) {
437 return (T)getOption(SocketOptions.SO_REUSEADDR);
438 } else if (name == StandardSocketOptions.SO_REUSEPORT &&
439 supportedOptions().contains(name)) {
440 return (T)getOption(SocketOptions.SO_REUSEPORT);
441 } else if (name == StandardSocketOptions.SO_LINGER &&
442 (getSocket() != null)) {
443 return (T)getOption(SocketOptions.SO_LINGER);
444 } else if (name == StandardSocketOptions.IP_TOS) {
445 return (T)getOption(SocketOptions.IP_TOS);
446 } else if (name == StandardSocketOptions.TCP_NODELAY &&
447 (getSocket() != null)) {
448 return (T)getOption(SocketOptions.TCP_NODELAY);
449 } else {
450 throw new UnsupportedOperationException("unsupported option");
451 }
452 }
453
454 private static final Set<SocketOption<?>> socketOptions;
455
456 private static final Set<SocketOption<?>> serverSocketOptions;
457
458 static {
459 socketOptions = Set.of(StandardSocketOptions.SO_KEEPALIVE,
460 StandardSocketOptions.SO_SNDBUF,
461 StandardSocketOptions.SO_RCVBUF,
462 StandardSocketOptions.SO_REUSEADDR,
463 StandardSocketOptions.SO_LINGER,
464 StandardSocketOptions.IP_TOS,
465 StandardSocketOptions.TCP_NODELAY);
466
467 serverSocketOptions = Set.of(StandardSocketOptions.SO_RCVBUF,
468 StandardSocketOptions.SO_REUSEADDR,
469 StandardSocketOptions.IP_TOS);
470 }
471
472 /**
473 * Returns a set of SocketOptions supported by this impl
474 * and by this impl's socket (Socket or ServerSocket)
475 *
476 * @return a Set of SocketOptions
477 *
478 * @since 9
479 */
480 protected Set<SocketOption<?>> supportedOptions() {
481 if (getSocket() != null) {
482 return socketOptions;
483 } else {
484 return serverSocketOptions;
485 }
486 }
487 }