1 /*
2 * Copyright (c) 2000, 2015, 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.util.Arrays;
29 import java.util.Enumeration;
30 import java.util.NoSuchElementException;
31 import java.security.AccessController;
32 import java.util.Spliterator;
33 import java.util.Spliterators;
34 import java.util.stream.Stream;
35 import java.util.stream.StreamSupport;
36
37 /**
38 * This class represents a Network Interface made up of a name,
39 * and a list of IP addresses assigned to this interface.
40 * It is used to identify the local interface on which a multicast group
41 * is joined.
42 *
43 * Interfaces are normally known by names such as "le0".
44 *
45 * @since 1.4
46 */
47 public final class NetworkInterface {
48 private String name;
49 private String displayName;
50 private int index;
51 private InetAddress addrs[];
52 private InterfaceAddress bindings[];
53 private NetworkInterface childs[];
54 private NetworkInterface parent = null;
55 private boolean virtual = false;
56 private static final NetworkInterface defaultInterface;
57 private static final int defaultIndex; /* index of defaultInterface */
58
59 static {
60 AccessController.doPrivileged(
61 new java.security.PrivilegedAction<>() {
62 public Void run() {
63 System.loadLibrary("net");
64 return null;
65 }
66 });
67
68 init();
69 defaultInterface = DefaultInterface.getDefault();
70 if (defaultInterface != null) {
71 defaultIndex = defaultInterface.getIndex();
72 } else {
73 defaultIndex = 0;
74 }
75 }
76
77 /**
78 * Returns an NetworkInterface object with index set to 0 and name to null.
79 * Setting such an interface on a MulticastSocket will cause the
80 * kernel to choose one interface for sending multicast packets.
81 *
82 */
83 NetworkInterface() {
84 }
85
86 NetworkInterface(String name, int index, InetAddress[] addrs) {
87 this.name = name;
88 this.index = index;
89 this.addrs = addrs;
90 }
91
92 /**
93 * Get the name of this network interface.
94 *
95 * @return the name of this network interface
96 */
97 public String getName() {
98 return name;
99 }
100
101 /**
102 * Get an Enumeration with all or a subset of the InetAddresses bound to
103 * this network interface.
104 * <p>
105 * If there is a security manager, its {@code checkConnect}
106 * method is called for each InetAddress. Only InetAddresses where
107 * the {@code checkConnect} doesn't throw a SecurityException
108 * will be returned in the Enumeration. However, if the caller has the
109 * {@link NetPermission}("getNetworkInformation") permission, then all
110 * InetAddresses are returned.
111 *
112 * @return an Enumeration object with all or a subset of the InetAddresses
113 * bound to this network interface
114 * @see #inetAddresses()
115 */
116 public Enumeration<InetAddress> getInetAddresses() {
117 return enumerationFromArray(getCheckedInetAddresses());
118 }
119
120 /**
121 * Get a Stream of all or a subset of the InetAddresses bound to this
122 * network interface.
123 * <p>
124 * If there is a security manager, its {@code checkConnect}
125 * method is called for each InetAddress. Only InetAddresses where
126 * the {@code checkConnect} doesn't throw a SecurityException will be
127 * returned in the Stream. However, if the caller has the
128 * {@link NetPermission}("getNetworkInformation") permission, then all
129 * InetAddresses are returned.
130 *
131 * @return a Stream object with all or a subset of the InetAddresses
132 * bound to this network interface
133 * @since 9
134 */
135 public Stream<InetAddress> inetAddresses() {
136 return streamFromArray(getCheckedInetAddresses());
137 }
138
139 private InetAddress[] getCheckedInetAddresses() {
140 InetAddress[] local_addrs = new InetAddress[addrs.length];
141 boolean trusted = true;
142
143 SecurityManager sec = System.getSecurityManager();
144 if (sec != null) {
145 try {
146 sec.checkPermission(new NetPermission("getNetworkInformation"));
147 } catch (SecurityException e) {
148 trusted = false;
149 }
150 }
151 int i = 0;
152 for (int j = 0; j < addrs.length; j++) {
153 try {
154 if (!trusted) {
155 sec.checkConnect(addrs[j].getHostAddress(), -1);
156 }
157 local_addrs[i++] = addrs[j];
158 } catch (SecurityException e) { }
159 }
160 return Arrays.copyOf(local_addrs, i);
161 }
162
163 /**
164 * Get a List of all or a subset of the {@code InterfaceAddresses}
165 * of this network interface.
166 * <p>
167 * If there is a security manager, its {@code checkConnect}
168 * method is called with the InetAddress for each InterfaceAddress.
169 * Only InterfaceAddresses where the {@code checkConnect} doesn't throw
170 * a SecurityException will be returned in the List.
171 *
172 * @return a {@code List} object with all or a subset of the
173 * InterfaceAddresss of this network interface
174 * @since 1.6
175 */
176 public java.util.List<InterfaceAddress> getInterfaceAddresses() {
177 java.util.List<InterfaceAddress> lst = new java.util.ArrayList<>(1);
178 SecurityManager sec = System.getSecurityManager();
179 for (int j=0; j<bindings.length; j++) {
180 try {
181 if (sec != null) {
182 sec.checkConnect(bindings[j].getAddress().getHostAddress(), -1);
183 }
184 lst.add(bindings[j]);
185 } catch (SecurityException e) { }
186 }
187 return lst;
188 }
189
190 /**
191 * Get an Enumeration with all the subinterfaces (also known as virtual
192 * interfaces) attached to this network interface.
193 * <p>
194 * For instance eth0:1 will be a subinterface to eth0.
195 *
196 * @return an Enumeration object with all of the subinterfaces
197 * of this network interface
198 * @see #subInterfaces()
199 * @since 1.6
200 */
201 public Enumeration<NetworkInterface> getSubInterfaces() {
202 return enumerationFromArray(childs);
203 }
204
205 /**
206 * Get a Stream of all subinterfaces (also known as virtual
207 * interfaces) attached to this network interface.
208 *
209 * @return a Stream object with all of the subinterfaces
210 * of this network interface
211 * @since 9
212 */
213 public Stream<NetworkInterface> subInterfaces() {
214 return streamFromArray(childs);
215 }
216
217 /**
218 * Returns the parent NetworkInterface of this interface if this is
219 * a subinterface, or {@code null} if it is a physical
220 * (non virtual) interface or has no parent.
221 *
222 * @return The {@code NetworkInterface} this interface is attached to.
223 * @since 1.6
224 */
225 public NetworkInterface getParent() {
226 return parent;
227 }
228
229 /**
230 * Returns the index of this network interface. The index is an integer greater
231 * or equal to zero, or {@code -1} for unknown. This is a system specific value
232 * and interfaces with the same name can have different indexes on different
233 * machines.
234 *
235 * @return the index of this network interface or {@code -1} if the index is
236 * unknown
237 * @see #getByIndex(int)
238 * @since 1.7
239 */
240 public int getIndex() {
241 return index;
242 }
243
244 /**
245 * Get the display name of this network interface.
246 * A display name is a human readable String describing the network
247 * device.
248 *
249 * @return a non-empty string representing the display name of this network
250 * interface, or null if no display name is available.
251 */
252 public String getDisplayName() {
253 /* strict TCK conformance */
254 return "".equals(displayName) ? null : displayName;
255 }
256
257 /**
258 * Searches for the network interface with the specified name.
259 *
260 * @param name
261 * The name of the network interface.
262 *
263 * @return A {@code NetworkInterface} with the specified name,
264 * or {@code null} if there is no network interface
265 * with the specified name.
266 *
267 * @throws SocketException
268 * If an I/O error occurs.
269 *
270 * @throws NullPointerException
271 * If the specified name is {@code null}.
272 */
273 public static NetworkInterface getByName(String name) throws SocketException {
274 if (name == null)
275 throw new NullPointerException();
276 return getByName0(name);
277 }
278
279 /**
280 * Get a network interface given its index.
281 *
282 * @param index an integer, the index of the interface
283 * @return the NetworkInterface obtained from its index, or {@code null} if
284 * there is no interface with such an index on the system
285 * @throws SocketException if an I/O error occurs.
286 * @throws IllegalArgumentException if index has a negative value
287 * @see #getIndex()
288 * @since 1.7
289 */
290 public static NetworkInterface getByIndex(int index) throws SocketException {
291 if (index < 0)
292 throw new IllegalArgumentException("Interface index can't be negative");
293 return getByIndex0(index);
294 }
295
296 /**
297 * Convenience method to search for a network interface that
298 * has the specified Internet Protocol (IP) address bound to
299 * it.
300 * <p>
301 * If the specified IP address is bound to multiple network
302 * interfaces it is not defined which network interface is
303 * returned.
304 *
305 * @param addr
306 * The {@code InetAddress} to search with.
307 *
308 * @return A {@code NetworkInterface}
309 * or {@code null} if there is no network interface
310 * with the specified IP address.
311 *
312 * @throws SocketException
313 * If an I/O error occurs.
314 *
315 * @throws NullPointerException
316 * If the specified address is {@code null}.
317 */
318 public static NetworkInterface getByInetAddress(InetAddress addr) throws SocketException {
319 if (addr == null) {
320 throw new NullPointerException();
321 }
322 if (!(addr instanceof Inet4Address || addr instanceof Inet6Address)) {
323 throw new IllegalArgumentException ("invalid address type");
324 }
325 return getByInetAddress0(addr);
326 }
327
328 /**
329 * Returns an {@code Enumeration} of all the interfaces on this machine. The
330 * {@code Enumeration} contains at least one element, possibly representing
331 * a loopback interface that only supports communication between entities on
332 * this machine.
333 *
334 * @apiNote this method can be used in combination with
335 * {@link #getInetAddresses()} to obtain all IP addresses for this node
336 *
337 * @return an Enumeration of NetworkInterfaces found on this machine
338 * @exception SocketException if an I/O error occurs.
339 * @see #networkInterfaces()
340 */
341 public static Enumeration<NetworkInterface> getNetworkInterfaces()
342 throws SocketException {
343 NetworkInterface[] netifs = getAll();
344 assert netifs != null && netifs.length > 0;
345
346 return enumerationFromArray(netifs);
347 }
348
349 /**
350 * Returns a {@code Stream} of all the interfaces on this machine. The
351 * {@code Stream} contains at least one interface, possibly representing a
352 * loopback interface that only supports communication between entities on
353 * this machine.
354 *
355 * @apiNote this method can be used in combination with
356 * {@link #inetAddresses()}} to obtain a stream of all IP addresses for
357 * this node, for example:
358 * <pre> {@code
359 * Stream<InetAddress> addrs = NetworkInterface.networkInterfaces()
360 * .flatMap(NetworkInterface::inetAddresses);
361 * }</pre>
362 *
363 * @return a Stream of NetworkInterfaces found on this machine
364 * @exception SocketException if an I/O error occurs.
365 * @since 9
366 */
367 public static Stream<NetworkInterface> networkInterfaces()
368 throws SocketException {
369 NetworkInterface[] netifs = getAll();
370 assert netifs != null && netifs.length > 0;
371
372 return streamFromArray(netifs);
373 }
374
375 private static <T> Enumeration<T> enumerationFromArray(T[] a) {
376 return new Enumeration<>() {
377 int i = 0;
378
379 @Override
380 public T nextElement() {
381 if (i < a.length) {
382 return a[i++];
383 } else {
384 throw new NoSuchElementException();
385 }
386 }
387
388 @Override
389 public boolean hasMoreElements() {
390 return i < a.length;
391 }
392 };
393 }
394
395 private static <T> Stream<T> streamFromArray(T[] a) {
396 return StreamSupport.stream(
397 Spliterators.spliterator(
398 a,
399 Spliterator.DISTINCT | Spliterator.IMMUTABLE | Spliterator.NONNULL),
400 false);
401 }
402
403 private static native NetworkInterface[] getAll()
404 throws SocketException;
405
406 private static native NetworkInterface getByName0(String name)
407 throws SocketException;
408
409 private static native NetworkInterface getByIndex0(int index)
410 throws SocketException;
411
412 private static native NetworkInterface getByInetAddress0(InetAddress addr)
413 throws SocketException;
414
415 /**
416 * Returns whether a network interface is up and running.
417 *
418 * @return {@code true} if the interface is up and running.
419 * @exception SocketException if an I/O error occurs.
420 * @since 1.6
421 */
422
423 public boolean isUp() throws SocketException {
424 return isUp0(name, index);
425 }
426
427 /**
428 * Returns whether a network interface is a loopback interface.
429 *
430 * @return {@code true} if the interface is a loopback interface.
431 * @exception SocketException if an I/O error occurs.
432 * @since 1.6
433 */
434
435 public boolean isLoopback() throws SocketException {
436 return isLoopback0(name, index);
437 }
438
439 /**
440 * Returns whether a network interface is a point to point interface.
441 * A typical point to point interface would be a PPP connection through
442 * a modem.
443 *
444 * @return {@code true} if the interface is a point to point
445 * interface.
446 * @exception SocketException if an I/O error occurs.
447 * @since 1.6
448 */
449
450 public boolean isPointToPoint() throws SocketException {
451 return isP2P0(name, index);
452 }
453
454 /**
455 * Returns whether a network interface supports multicasting or not.
456 *
457 * @return {@code true} if the interface supports Multicasting.
458 * @exception SocketException if an I/O error occurs.
459 * @since 1.6
460 */
461
462 public boolean supportsMulticast() throws SocketException {
463 return supportsMulticast0(name, index);
464 }
465
466 /**
467 * Returns the hardware address (usually MAC) of the interface if it
468 * has one and if it can be accessed given the current privileges.
469 * If a security manager is set, then the caller must have
470 * the permission {@link NetPermission}("getNetworkInformation").
471 *
472 * @return a byte array containing the address, or {@code null} if
473 * the address doesn't exist, is not accessible or a security
474 * manager is set and the caller does not have the permission
475 * NetPermission("getNetworkInformation")
476 *
477 * @exception SocketException if an I/O error occurs.
478 * @since 1.6
479 */
480 public byte[] getHardwareAddress() throws SocketException {
481 SecurityManager sec = System.getSecurityManager();
482 if (sec != null) {
483 try {
484 sec.checkPermission(new NetPermission("getNetworkInformation"));
485 } catch (SecurityException e) {
486 if (!getInetAddresses().hasMoreElements()) {
487 // don't have connect permission to any local address
488 return null;
489 }
490 }
491 }
492 for (InetAddress addr : addrs) {
493 if (addr instanceof Inet4Address) {
494 return getMacAddr0(((Inet4Address)addr).getAddress(), name, index);
495 }
496 }
497 return getMacAddr0(null, name, index);
498 }
499
500 /**
501 * Returns the Maximum Transmission Unit (MTU) of this interface.
502 *
503 * @return the value of the MTU for that interface.
504 * @exception SocketException if an I/O error occurs.
505 * @since 1.6
506 */
507 public int getMTU() throws SocketException {
508 return getMTU0(name, index);
509 }
510
511 /**
512 * Returns whether this interface is a virtual interface (also called
513 * subinterface).
514 * Virtual interfaces are, on some systems, interfaces created as a child
515 * of a physical interface and given different settings (like address or
516 * MTU). Usually the name of the interface will the name of the parent
517 * followed by a colon (:) and a number identifying the child since there
518 * can be several virtual interfaces attached to a single physical
519 * interface.
520 *
521 * @return {@code true} if this interface is a virtual interface.
522 * @since 1.6
523 */
524 public boolean isVirtual() {
525 return virtual;
526 }
527
528 private static native boolean isUp0(String name, int ind) throws SocketException;
529 private static native boolean isLoopback0(String name, int ind) throws SocketException;
530 private static native boolean supportsMulticast0(String name, int ind) throws SocketException;
531 private static native boolean isP2P0(String name, int ind) throws SocketException;
532 private static native byte[] getMacAddr0(byte[] inAddr, String name, int ind) throws SocketException;
533 private static native int getMTU0(String name, int ind) throws SocketException;
534
535 /**
536 * Compares this object against the specified object.
537 * The result is {@code true} if and only if the argument is
538 * not {@code null} and it represents the same NetworkInterface
539 * as this object.
540 * <p>
541 * Two instances of {@code NetworkInterface} represent the same
542 * NetworkInterface if both name and addrs are the same for both.
543 *
544 * @param obj the object to compare against.
545 * @return {@code true} if the objects are the same;
546 * {@code false} otherwise.
547 * @see java.net.InetAddress#getAddress()
548 */
549 public boolean equals(Object obj) {
550 if (!(obj instanceof NetworkInterface)) {
551 return false;
552 }
553 NetworkInterface that = (NetworkInterface)obj;
554 if (this.name != null ) {
555 if (!this.name.equals(that.name)) {
556 return false;
557 }
558 } else {
559 if (that.name != null) {
560 return false;
561 }
562 }
563
564 if (this.addrs == null) {
565 return that.addrs == null;
566 } else if (that.addrs == null) {
567 return false;
568 }
569
570 /* Both addrs not null. Compare number of addresses */
571
572 if (this.addrs.length != that.addrs.length) {
573 return false;
574 }
575
576 InetAddress[] thatAddrs = that.addrs;
577 int count = thatAddrs.length;
578
579 for (int i=0; i<count; i++) {
580 boolean found = false;
581 for (int j=0; j<count; j++) {
582 if (addrs[i].equals(thatAddrs[j])) {
583 found = true;
584 break;
585 }
586 }
587 if (!found) {
588 return false;
589 }
590 }
591 return true;
592 }
593
594 public int hashCode() {
595 return name == null? 0: name.hashCode();
596 }
597
598 public String toString() {
599 String result = "name:";
600 result += name == null? "null": name;
601 if (displayName != null) {
602 result += " (" + displayName + ")";
603 }
604 return result;
605 }
606
607 private static native void init();
608
609 /**
610 * Returns the default network interface of this system
611 *
612 * @return the default interface
613 */
614 static NetworkInterface getDefault() {
615 return defaultInterface;
616 }
617 }