1 /*
2 * Copyright (c) 2000, 2019, 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 sun.nio.ch;
27
28 import java.io.FileDescriptor;
29 import java.io.IOException;
30 import java.net.Inet4Address;
31 import java.net.Inet6Address;
32 import java.net.InetAddress;
33 import java.net.InetSocketAddress;
34 import java.net.NetworkInterface;
35 import java.net.ProtocolFamily;
36 import java.net.SocketAddress;
37 import java.net.SocketException;
38 import java.net.SocketOption;
39 import java.net.StandardProtocolFamily;
40 import java.net.StandardSocketOptions;
41 import java.net.UnknownHostException;
42 import java.nio.channels.AlreadyBoundException;
43 import java.nio.channels.ClosedChannelException;
44 import java.nio.channels.NotYetBoundException;
45 import java.nio.channels.NotYetConnectedException;
46 import java.nio.channels.UnresolvedAddressException;
47 import java.nio.channels.UnsupportedAddressTypeException;
48 import java.security.AccessController;
49 import java.security.PrivilegedAction;
50 import java.util.Enumeration;
51
52 import sun.net.ext.ExtendedSocketOptions;
53 import sun.net.util.IPAddressUtil;
54 import sun.security.action.GetPropertyAction;
55
56 public class Net {
57
58 private Net() { }
59
60 // unspecified protocol family
61 static final ProtocolFamily UNSPEC = new ProtocolFamily() {
62 public String name() {
63 return "UNSPEC";
64 }
65 };
66
67 // set to true if exclusive binding is on for Windows
68 private static final boolean exclusiveBind;
69
70 // set to true if the fast tcp loopback should be enabled on Windows
71 private static final boolean fastLoopback;
72
73 // -- Miscellaneous utilities --
74
75 private static volatile boolean checkedIPv6;
76 private static volatile boolean isIPv6Available;
77 private static volatile boolean checkedReusePort;
78 private static volatile boolean isReusePortAvailable;
79
80 /**
81 * Tells whether dual-IPv4/IPv6 sockets should be used.
82 */
83 static boolean isIPv6Available() {
84 if (!checkedIPv6) {
85 isIPv6Available = isIPv6Available0();
86 checkedIPv6 = true;
87 }
88 return isIPv6Available;
89 }
90
91 /**
92 * Tells whether SO_REUSEPORT is supported.
93 */
94 static boolean isReusePortAvailable() {
95 if (!checkedReusePort) {
96 isReusePortAvailable = isReusePortAvailable0();
97 checkedReusePort = true;
98 }
99 return isReusePortAvailable;
100 }
101
102 /**
103 * Returns true if exclusive binding is on
104 */
105 static boolean useExclusiveBind() {
106 return exclusiveBind;
107 }
108
109 /**
110 * Tells whether both IPV6_XXX and IP_XXX socket options should be set on
111 * IPv6 sockets. On some kernels, both IPV6_XXX and IP_XXX socket options
112 * need to be set so that the settings are effective for IPv4 multicast
113 * datagrams sent using the socket.
114 */
115 static boolean shouldSetBothIPv4AndIPv6Options() {
116 return shouldSetBothIPv4AndIPv6Options0();
117 }
118
119 /**
120 * Tells whether IPv6 sockets can join IPv4 multicast groups
121 */
122 static boolean canIPv6SocketJoinIPv4Group() {
123 return canIPv6SocketJoinIPv4Group0();
124 }
125
126 /**
127 * Tells whether {@link #join6} can be used to join an IPv4
128 * multicast group (IPv4 group as IPv4-mapped IPv6 address)
129 */
130 static boolean canJoin6WithIPv4Group() {
131 return canJoin6WithIPv4Group0();
132 }
133
134 /**
135 * Tells whether IPV6_XXX socket options should be used on an IPv6 socket
136 * that is bound to an IPv4 address.
137 */
138 static boolean canUseIPv6OptionsWithIPv4LocalAddress() {
139 return canUseIPv6OptionsWithIPv4LocalAddress0();
140 }
141
142 public static InetSocketAddress checkAddress(SocketAddress sa) {
143 if (sa == null)
144 throw new NullPointerException();
145 if (!(sa instanceof InetSocketAddress))
146 throw new UnsupportedAddressTypeException(); // ## needs arg
147 InetSocketAddress isa = (InetSocketAddress)sa;
148 if (isa.isUnresolved())
149 throw new UnresolvedAddressException(); // ## needs arg
150 InetAddress addr = isa.getAddress();
151 if (!(addr instanceof Inet4Address || addr instanceof Inet6Address))
152 throw new IllegalArgumentException("Invalid address type");
153 return isa;
154 }
155
156 static InetSocketAddress checkAddress(SocketAddress sa, ProtocolFamily family) {
157 InetSocketAddress isa = checkAddress(sa);
158 if (family == StandardProtocolFamily.INET) {
159 InetAddress addr = isa.getAddress();
160 if (!(addr instanceof Inet4Address))
161 throw new UnsupportedAddressTypeException();
162 }
163 return isa;
164 }
165
166 static InetSocketAddress asInetSocketAddress(SocketAddress sa) {
167 if (!(sa instanceof InetSocketAddress))
168 throw new UnsupportedAddressTypeException();
169 return (InetSocketAddress)sa;
170 }
171
172 static void translateToSocketException(Exception x)
173 throws SocketException
174 {
175 if (x instanceof SocketException)
176 throw (SocketException)x;
177 Exception nx = x;
178 if (x instanceof ClosedChannelException)
179 nx = new SocketException("Socket is closed");
180 else if (x instanceof NotYetConnectedException)
181 nx = new SocketException("Socket is not connected");
182 else if (x instanceof AlreadyBoundException)
183 nx = new SocketException("Already bound");
184 else if (x instanceof NotYetBoundException)
185 nx = new SocketException("Socket is not bound yet");
186 else if (x instanceof UnsupportedAddressTypeException)
187 nx = new SocketException("Unsupported address type");
188 else if (x instanceof UnresolvedAddressException) {
189 nx = new SocketException("Unresolved address");
190 }
191 if (nx != x)
192 nx.initCause(x);
193
194 if (nx instanceof SocketException)
195 throw (SocketException)nx;
196 else if (nx instanceof RuntimeException)
197 throw (RuntimeException)nx;
198 else
199 throw new Error("Untranslated exception", nx);
200 }
201
202 static void translateException(Exception x,
203 boolean unknownHostForUnresolved)
204 throws IOException
205 {
206 if (x instanceof IOException)
207 throw (IOException)x;
208 // Throw UnknownHostException from here since it cannot
209 // be thrown as a SocketException
210 if (unknownHostForUnresolved &&
211 (x instanceof UnresolvedAddressException))
212 {
213 throw new UnknownHostException();
214 }
215 translateToSocketException(x);
216 }
217
218 static void translateException(Exception x)
219 throws IOException
220 {
221 translateException(x, false);
222 }
223
224 /**
225 * Returns the local address after performing a SecurityManager#checkConnect.
226 */
227 static InetSocketAddress getRevealedLocalAddress(InetSocketAddress addr) {
228 SecurityManager sm = System.getSecurityManager();
229 if (addr == null || sm == null)
230 return addr;
231
232 try{
233 sm.checkConnect(addr.getAddress().getHostAddress(), -1);
234 // Security check passed
235 } catch (SecurityException e) {
236 // Return loopback address only if security check fails
237 addr = getLoopbackAddress(addr.getPort());
238 }
239 return addr;
240 }
241
242 static String getRevealedLocalAddressAsString(InetSocketAddress addr) {
243 return System.getSecurityManager() == null ? addr.toString() :
244 getLoopbackAddress(addr.getPort()).toString();
245 }
246
247 private static InetSocketAddress getLoopbackAddress(int port) {
248 return new InetSocketAddress(InetAddress.getLoopbackAddress(),
249 port);
250 }
251
252 /**
253 * Returns any IPv4 address of the given network interface, or
254 * null if the interface does not have any IPv4 addresses.
255 */
256 static Inet4Address anyInet4Address(final NetworkInterface interf) {
257 return AccessController.doPrivileged(new PrivilegedAction<Inet4Address>() {
258 public Inet4Address run() {
259 Enumeration<InetAddress> addrs = interf.getInetAddresses();
260 while (addrs.hasMoreElements()) {
261 InetAddress addr = addrs.nextElement();
262 if (addr instanceof Inet4Address) {
263 return (Inet4Address)addr;
264 }
265 }
266 return null;
267 }
268 });
269 }
270
271 /**
272 * Returns an IPv4 address as an int.
273 */
274 static int inet4AsInt(InetAddress ia) {
275 if (ia instanceof Inet4Address) {
276 byte[] addr = ia.getAddress();
277 int address = addr[3] & 0xFF;
278 address |= ((addr[2] << 8) & 0xFF00);
279 address |= ((addr[1] << 16) & 0xFF0000);
280 address |= ((addr[0] << 24) & 0xFF000000);
281 return address;
282 }
283 throw new AssertionError("Should not reach here");
284 }
285
286 /**
287 * Returns an InetAddress from the given IPv4 address
288 * represented as an int.
289 */
290 static InetAddress inet4FromInt(int address) {
291 byte[] addr = new byte[4];
292 addr[0] = (byte) ((address >>> 24) & 0xFF);
293 addr[1] = (byte) ((address >>> 16) & 0xFF);
294 addr[2] = (byte) ((address >>> 8) & 0xFF);
295 addr[3] = (byte) (address & 0xFF);
296 try {
297 return InetAddress.getByAddress(addr);
298 } catch (UnknownHostException uhe) {
299 throw new AssertionError("Should not reach here");
300 }
301 }
302
303 /**
304 * Returns an IPv6 address as a byte array
305 */
306 static byte[] inet6AsByteArray(InetAddress ia) {
307 if (ia instanceof Inet6Address) {
308 return ia.getAddress();
309 }
310
311 // need to construct IPv4-mapped address
312 if (ia instanceof Inet4Address) {
313 byte[] ip4address = ia.getAddress();
314 byte[] address = new byte[16];
315 address[10] = (byte)0xff;
316 address[11] = (byte)0xff;
317 address[12] = ip4address[0];
318 address[13] = ip4address[1];
319 address[14] = ip4address[2];
320 address[15] = ip4address[3];
321 return address;
322 }
323
324 throw new AssertionError("Should not reach here");
325 }
326
327 // -- Socket options
328
329 static final ExtendedSocketOptions extendedOptions =
330 ExtendedSocketOptions.getInstance();
331
332 static void setSocketOption(FileDescriptor fd, SocketOption<?> name, Object value)
333 throws IOException
334 {
335 setSocketOption(fd, Net.UNSPEC, name, value);
336 }
337
338 static void setSocketOption(FileDescriptor fd, ProtocolFamily family,
339 SocketOption<?> name, Object value)
340 throws IOException
341 {
342 if (value == null)
343 throw new IllegalArgumentException("Invalid option value");
344
345 // only simple values supported by this method
346 Class<?> type = name.type();
347
348 if (extendedOptions.isOptionSupported(name)) {
349 extendedOptions.setOption(fd, name, value);
350 return;
351 }
352
353 if (type != Integer.class && type != Boolean.class)
354 throw new AssertionError("Should not reach here");
355
356 // special handling
357 if (name == StandardSocketOptions.SO_RCVBUF ||
358 name == StandardSocketOptions.SO_SNDBUF)
359 {
360 int i = ((Integer)value).intValue();
361 if (i < 0)
362 throw new IllegalArgumentException("Invalid send/receive buffer size");
363 }
364 if (name == StandardSocketOptions.SO_LINGER) {
365 int i = ((Integer)value).intValue();
366 if (i < 0)
367 value = Integer.valueOf(-1);
368 if (i > 65535)
369 value = Integer.valueOf(65535);
370 }
371 if (name == StandardSocketOptions.IP_TOS) {
372 int i = ((Integer)value).intValue();
373 if (i < 0 || i > 255)
374 throw new IllegalArgumentException("Invalid IP_TOS value");
375 }
376 if (name == StandardSocketOptions.IP_MULTICAST_TTL) {
377 int i = ((Integer)value).intValue();
378 if (i < 0 || i > 255)
379 throw new IllegalArgumentException("Invalid TTL/hop value");
380 }
381
382 // map option name to platform level/name
383 OptionKey key = SocketOptionRegistry.findOption(name, family);
384 if (key == null)
385 throw new AssertionError("Option not found");
386
387 int arg;
388 if (type == Integer.class) {
389 arg = ((Integer)value).intValue();
390 } else {
391 boolean b = ((Boolean)value).booleanValue();
392 arg = (b) ? 1 : 0;
393 }
394
395 boolean mayNeedConversion = (family == UNSPEC);
396 boolean isIPv6 = (family == StandardProtocolFamily.INET6);
397 setIntOption0(fd, mayNeedConversion, key.level(), key.name(), arg, isIPv6);
398 }
399
400 static Object getSocketOption(FileDescriptor fd, SocketOption<?> name)
401 throws IOException
402 {
403 return getSocketOption(fd, Net.UNSPEC, name);
404 }
405
406 static Object getSocketOption(FileDescriptor fd, ProtocolFamily family, SocketOption<?> name)
407 throws IOException
408 {
409 Class<?> type = name.type();
410
411 if (extendedOptions.isOptionSupported(name)) {
412 return extendedOptions.getOption(fd, name);
413 }
414
415 // only simple values supported by this method
416 if (type != Integer.class && type != Boolean.class)
417 throw new AssertionError("Should not reach here");
418
419 // map option name to platform level/name
420 OptionKey key = SocketOptionRegistry.findOption(name, family);
421 if (key == null)
422 throw new AssertionError("Option not found");
423
424 boolean mayNeedConversion = (family == UNSPEC);
425 int value = getIntOption0(fd, mayNeedConversion, key.level(), key.name());
426
427 if (type == Integer.class) {
428 return Integer.valueOf(value);
429 } else {
430 return (value == 0) ? Boolean.FALSE : Boolean.TRUE;
431 }
432 }
433
434 public static boolean isFastTcpLoopbackRequested() {
435 String loopbackProp = GetPropertyAction
436 .privilegedGetProperty("jdk.net.useFastTcpLoopback", "false");
437 return loopbackProp.isEmpty() ? true : Boolean.parseBoolean(loopbackProp);
438 }
439
440 // -- Socket operations --
441
442 private static native boolean isIPv6Available0();
443
444 private static native boolean isReusePortAvailable0();
445
446 /*
447 * Returns 1 for Windows and -1 for Linux/Mac OS
448 */
449 private static native int isExclusiveBindAvailable();
450
451 private static native boolean shouldSetBothIPv4AndIPv6Options0();
452
453 private static native boolean canIPv6SocketJoinIPv4Group0();
454
455 private static native boolean canJoin6WithIPv4Group0();
456
457 private static native boolean canUseIPv6OptionsWithIPv4LocalAddress0();
458
459 static FileDescriptor socket(boolean stream) throws IOException {
460 return socket(UNSPEC, stream);
461 }
462
463 static FileDescriptor socket(ProtocolFamily family, boolean stream) throws IOException {
464 boolean preferIPv6 = isIPv6Available() &&
465 (family != StandardProtocolFamily.INET);
466 return IOUtil.newFD(socket0(preferIPv6, stream, false, fastLoopback));
467 }
468
469 static FileDescriptor serverSocket(boolean stream) {
470 return IOUtil.newFD(socket0(isIPv6Available(), stream, true, fastLoopback));
471 }
472
473 // Due to oddities SO_REUSEADDR on windows reuse is ignored
474 private static native int socket0(boolean preferIPv6, boolean stream, boolean reuse,
475 boolean fastLoopback);
476
477 public static void bind(FileDescriptor fd, InetAddress addr, int port)
478 throws IOException
479 {
480 bind(UNSPEC, fd, addr, port);
481 }
482
483 static void bind(ProtocolFamily family, FileDescriptor fd,
484 InetAddress addr, int port) throws IOException
485 {
486 boolean preferIPv6 = isIPv6Available() &&
487 (family != StandardProtocolFamily.INET);
488 if (addr.isLinkLocalAddress()) {
489 addr = IPAddressUtil.toScopedAddress(addr);
490 }
491 bind0(fd, preferIPv6, exclusiveBind, addr, port);
492 }
493
494 private static native void bind0(FileDescriptor fd, boolean preferIPv6,
495 boolean useExclBind, InetAddress addr,
496 int port)
497 throws IOException;
498
499 static native void listen(FileDescriptor fd, int backlog) throws IOException;
500
501 static int connect(FileDescriptor fd, InetAddress remote, int remotePort)
502 throws IOException
503 {
504 return connect(UNSPEC, fd, remote, remotePort);
505 }
506
507 static int connect(ProtocolFamily family, FileDescriptor fd, InetAddress remote, int remotePort)
508 throws IOException
509 {
510 if (remote.isLinkLocalAddress()) {
511 remote = IPAddressUtil.toScopedAddress(remote);
512 }
513 boolean preferIPv6 = isIPv6Available() &&
514 (family != StandardProtocolFamily.INET);
515 return connect0(preferIPv6, fd, remote, remotePort);
516 }
517
518 private static native int connect0(boolean preferIPv6,
519 FileDescriptor fd,
520 InetAddress remote,
521 int remotePort)
522 throws IOException;
523
524 public static native int accept(FileDescriptor fd,
525 FileDescriptor newfd,
526 InetSocketAddress[] isaa)
527 throws IOException;
528
529 public static final int SHUT_RD = 0;
530 public static final int SHUT_WR = 1;
531 public static final int SHUT_RDWR = 2;
532
533 static native void shutdown(FileDescriptor fd, int how) throws IOException;
534
535 private static native int localPort(FileDescriptor fd)
536 throws IOException;
537
538 private static native InetAddress localInetAddress(FileDescriptor fd)
539 throws IOException;
540
541 public static InetSocketAddress localAddress(FileDescriptor fd)
542 throws IOException
543 {
544 return new InetSocketAddress(localInetAddress(fd), localPort(fd));
545 }
546
547 private static native int remotePort(FileDescriptor fd)
548 throws IOException;
549
550 private static native InetAddress remoteInetAddress(FileDescriptor fd)
551 throws IOException;
552
553 static InetSocketAddress remoteAddress(FileDescriptor fd)
554 throws IOException
555 {
556 return new InetSocketAddress(remoteInetAddress(fd), remotePort(fd));
557 }
558
559 private static native int getIntOption0(FileDescriptor fd, boolean mayNeedConversion,
560 int level, int opt)
561 throws IOException;
562
563 private static native void setIntOption0(FileDescriptor fd, boolean mayNeedConversion,
564 int level, int opt, int arg, boolean isIPv6)
565 throws IOException;
566
567 /**
568 * Polls a file descriptor for events.
569 * @param timeout the timeout to wait; 0 to not wait, -1 to wait indefinitely
570 * @return the polled events or 0 if no events are polled
571 */
572 static native int poll(FileDescriptor fd, int events, long timeout)
573 throws IOException;
574
575 /**
576 * Performs a non-blocking poll of a file descriptor.
577 * @return the polled events or 0 if no events are polled
578 */
579 static int pollNow(FileDescriptor fd, int events) throws IOException {
580 return poll(fd, events, 0);
581 }
582
583 /**
584 * Polls a connecting socket to test if the connection has been established.
585 *
586 * @apiNote This method is public to allow it be used by code in jdk.sctp.
587 *
588 * @param timeout the timeout to wait; 0 to not wait, -1 to wait indefinitely
589 * @return true if connected
590 */
591 public static native boolean pollConnect(FileDescriptor fd, long timeout)
592 throws IOException;
593
594 /**
595 * Performs a non-blocking poll of a connecting socket to test if the
596 * connection has been established.
597 *
598 * @return true if connected
599 */
600 static boolean pollConnectNow(FileDescriptor fd) throws IOException {
601 return pollConnect(fd, 0);
602 }
603
604 /**
605 * Return the number of bytes in the socket input buffer.
606 */
607 static native int available(FileDescriptor fd) throws IOException;
608
609 /**
610 * Send one byte of urgent data (MSG_OOB) on the socket.
611 */
612 static native int sendOOB(FileDescriptor fd, byte data) throws IOException;
613
614
615 // -- Multicast support --
616
617 /**
618 * Join IPv4 multicast group
619 */
620 static int join4(FileDescriptor fd, int group, int interf, int source)
621 throws IOException
622 {
623 return joinOrDrop4(true, fd, group, interf, source);
624 }
625
626 /**
627 * Drop membership of IPv4 multicast group
628 */
629 static void drop4(FileDescriptor fd, int group, int interf, int source)
630 throws IOException
631 {
632 joinOrDrop4(false, fd, group, interf, source);
633 }
634
635 private static native int joinOrDrop4(boolean join, FileDescriptor fd, int group, int interf, int source)
636 throws IOException;
637
638 /**
639 * Block IPv4 source
640 */
641 static int block4(FileDescriptor fd, int group, int interf, int source)
642 throws IOException
643 {
644 return blockOrUnblock4(true, fd, group, interf, source);
645 }
646
647 /**
648 * Unblock IPv6 source
649 */
650 static void unblock4(FileDescriptor fd, int group, int interf, int source)
651 throws IOException
652 {
653 blockOrUnblock4(false, fd, group, interf, source);
654 }
655
656 private static native int blockOrUnblock4(boolean block, FileDescriptor fd, int group,
657 int interf, int source)
658 throws IOException;
659
660 /**
661 * Join IPv6 multicast group
662 */
663 static int join6(FileDescriptor fd, byte[] group, int index, byte[] source)
664 throws IOException
665 {
666 return joinOrDrop6(true, fd, group, index, source);
667 }
668
669 /**
670 * Drop membership of IPv6 multicast group
671 */
672 static void drop6(FileDescriptor fd, byte[] group, int index, byte[] source)
673 throws IOException
674 {
675 joinOrDrop6(false, fd, group, index, source);
676 }
677
678 private static native int joinOrDrop6(boolean join, FileDescriptor fd, byte[] group, int index, byte[] source)
679 throws IOException;
680
681 /**
682 * Block IPv6 source
683 */
684 static int block6(FileDescriptor fd, byte[] group, int index, byte[] source)
685 throws IOException
686 {
687 return blockOrUnblock6(true, fd, group, index, source);
688 }
689
690 /**
691 * Unblock IPv6 source
692 */
693 static void unblock6(FileDescriptor fd, byte[] group, int index, byte[] source)
694 throws IOException
695 {
696 blockOrUnblock6(false, fd, group, index, source);
697 }
698
699 static native int blockOrUnblock6(boolean block, FileDescriptor fd, byte[] group, int index, byte[] source)
700 throws IOException;
701
702 static native void setInterface4(FileDescriptor fd, int interf) throws IOException;
703
704 static native int getInterface4(FileDescriptor fd) throws IOException;
705
706 static native void setInterface6(FileDescriptor fd, int index) throws IOException;
707
708 static native int getInterface6(FileDescriptor fd) throws IOException;
709
710 private static native void initIDs();
711
712 /**
713 * Event masks for the various poll system calls.
714 * They will be set platform dependent in the static initializer below.
715 */
716 public static final short POLLIN;
717 public static final short POLLOUT;
718 public static final short POLLERR;
719 public static final short POLLHUP;
720 public static final short POLLNVAL;
721 public static final short POLLCONN;
722
723 static native short pollinValue();
724 static native short polloutValue();
725 static native short pollerrValue();
726 static native short pollhupValue();
727 static native short pollnvalValue();
728 static native short pollconnValue();
729
730 static {
731 IOUtil.load();
732 initIDs();
733
734 POLLIN = pollinValue();
735 POLLOUT = polloutValue();
736 POLLERR = pollerrValue();
737 POLLHUP = pollhupValue();
738 POLLNVAL = pollnvalValue();
739 POLLCONN = pollconnValue();
740 }
741
742 static {
743 int availLevel = isExclusiveBindAvailable();
744 if (availLevel >= 0) {
745 String exclBindProp = GetPropertyAction
746 .privilegedGetProperty("sun.net.useExclusiveBind");
747 if (exclBindProp != null) {
748 exclusiveBind = exclBindProp.isEmpty() ?
749 true : Boolean.parseBoolean(exclBindProp);
750 } else if (availLevel == 1) {
751 exclusiveBind = true;
752 } else {
753 exclusiveBind = false;
754 }
755 } else {
756 exclusiveBind = false;
757 }
758
759 fastLoopback = isFastTcpLoopbackRequested();
760 }
761 }