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 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
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 }