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	/*
	* Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package java.net;

	import java.util.Arrays;
	import java.util.Enumeration;
	import java.util.NoSuchElementException;
	import java.security.AccessController;
	import java.util.Spliterator;
	import java.util.Spliterators;
	import java.util.stream.Stream;
	import java.util.stream.StreamSupport;

	/**
	* This class represents a Network Interface made up of a name,
	* and a list of IP addresses assigned to this interface.
	* It is used to identify the local interface on which a multicast group
	* is joined.
	*
	* Interfaces are normally known by names such as "le0".
	*
	* @since 1.4
	*/
	public final class NetworkInterface {
	private String name;
	private String displayName;
	private int index;
	private InetAddress addrs[];
	private InterfaceAddress bindings[];
	private NetworkInterface childs[];
	private NetworkInterface parent = null;
	private boolean virtual = false;
	private static final NetworkInterface defaultInterface;
	private static final int defaultIndex; /* index of defaultInterface */

	static {
	AccessController.doPrivileged(
	new java.security.PrivilegedAction<>() {
	public Void run() {
	System.loadLibrary("net");
	return null;
	}
	});

	init();
	defaultInterface = DefaultInterface.getDefault();
	if (defaultInterface != null) {
	defaultIndex = defaultInterface.getIndex();
	} else {
	defaultIndex = 0;
	}
	}

	/**
	* Returns an NetworkInterface object with index set to 0 and name to null.
	* Setting such an interface on a MulticastSocket will cause the
	* kernel to choose one interface for sending multicast packets.
	*
	*/
	NetworkInterface() {
	}

	NetworkInterface(String name, int index, InetAddress[] addrs) {
	this.name = name;
	this.index = index;
	this.addrs = addrs;
	}

	/**
	* Get the name of this network interface.
	*
	* @return the name of this network interface
	*/
	public String getName() {
	return name;
	}

	/**
	* Get an Enumeration with all or a subset of the InetAddresses bound to
	* this network interface.
	* <p>
	* If there is a security manager, its {@code checkConnect}
	* method is called for each InetAddress. Only InetAddresses where
	* the {@code checkConnect} doesn't throw a SecurityException
	* will be returned in the Enumeration. However, if the caller has the
	* {@link NetPermission}("getNetworkInformation") permission, then all
	* InetAddresses are returned.
	*
	* @return an Enumeration object with all or a subset of the InetAddresses
	* bound to this network interface
	* @see #inetAddresses()
	*/
	public Enumeration<InetAddress> getInetAddresses() {
	return enumerationFromArray(getCheckedInetAddresses());
	}

	/**
	* Get a Stream of all or a subset of the InetAddresses bound to this
	* network interface.
	* <p>
	* If there is a security manager, its {@code checkConnect}
	* method is called for each InetAddress. Only InetAddresses where
	* the {@code checkConnect} doesn't throw a SecurityException will be
	* returned in the Stream. However, if the caller has the
	* {@link NetPermission}("getNetworkInformation") permission, then all
	* InetAddresses are returned.
	*
	* @return a Stream object with all or a subset of the InetAddresses
	* bound to this network interface
	* @since 9
	*/
	public Stream<InetAddress> inetAddresses() {
	return streamFromArray(getCheckedInetAddresses());
	}

	private InetAddress[] getCheckedInetAddresses() {
	InetAddress[] local_addrs = new InetAddress[addrs.length];
	boolean trusted = true;

	SecurityManager sec = System.getSecurityManager();
	if (sec != null) {
	try {
	sec.checkPermission(new NetPermission("getNetworkInformation"));
	} catch (SecurityException e) {
	trusted = false;
	}
	}
	int i = 0;
	for (int j = 0; j < addrs.length; j++) {
	try {
	if (!trusted) {
	sec.checkConnect(addrs[j].getHostAddress(), -1);
	}
	local_addrs[i++] = addrs[j];
	} catch (SecurityException e) { }
	}
	return Arrays.copyOf(local_addrs, i);
	}

	/**
	* Get a List of all or a subset of the {@code InterfaceAddresses}
	* of this network interface.
	* <p>
	* If there is a security manager, its {@code checkConnect}
	* method is called with the InetAddress for each InterfaceAddress.
	* Only InterfaceAddresses where the {@code checkConnect} doesn't throw
	* a SecurityException will be returned in the List.
	*
	* @return a {@code List} object with all or a subset of the
	* InterfaceAddresss of this network interface
	* @since 1.6
	*/
	public java.util.List<InterfaceAddress> getInterfaceAddresses() {
	java.util.List<InterfaceAddress> lst = new java.util.ArrayList<>(1);
	if (bindings != null) {
	SecurityManager sec = System.getSecurityManager();
	for (int j=0; j<bindings.length; j++) {
	try {
	if (sec != null) {
	sec.checkConnect(bindings[j].getAddress().getHostAddress(), -1);
	}
	lst.add(bindings[j]);
	} catch (SecurityException e) { }
	}
	}
	return lst;
	}

	/**
	* Get an Enumeration with all the subinterfaces (also known as virtual
	* interfaces) attached to this network interface.
	* <p>
	* For instance eth0:1 will be a subinterface to eth0.
	*
	* @return an Enumeration object with all of the subinterfaces
	* of this network interface
	* @see #subInterfaces()
	* @since 1.6
	*/
	public Enumeration<NetworkInterface> getSubInterfaces() {
	return enumerationFromArray(childs);
	}

	/**
	* Get a Stream of all subinterfaces (also known as virtual
	* interfaces) attached to this network interface.
	*
	* @return a Stream object with all of the subinterfaces
	* of this network interface
	* @since 9
	*/
	public Stream<NetworkInterface> subInterfaces() {
	return streamFromArray(childs);
	}

	/**
	* Returns the parent NetworkInterface of this interface if this is
	* a subinterface, or {@code null} if it is a physical
	* (non virtual) interface or has no parent.
	*
	* @return The {@code NetworkInterface} this interface is attached to.
	* @since 1.6
	*/
	public NetworkInterface getParent() {
	return parent;
	}

	/**
	* Returns the index of this network interface. The index is an integer greater
	* or equal to zero, or {@code -1} for unknown. This is a system specific value
	* and interfaces with the same name can have different indexes on different
	* machines.
	*
	* @return the index of this network interface or {@code -1} if the index is
	* unknown
	* @see #getByIndex(int)
	* @since 1.7
	*/
	public int getIndex() {
	return index;
	}

	/**
	* Get the display name of this network interface.
	* A display name is a human readable String describing the network
	* device.
	*
	* @return a non-empty string representing the display name of this network
	* interface, or null if no display name is available.
	*/
	public String getDisplayName() {
	/* strict TCK conformance */
	return "".equals(displayName) ? null : displayName;
	}

	/**
	* Searches for the network interface with the specified name.
	*
	* @param name
	* The name of the network interface.
	*
	* @return A {@code NetworkInterface} with the specified name,
	* or {@code null} if there is no network interface
	* with the specified name.
	*
	* @throws SocketException
	* If an I/O error occurs.
	*
	* @throws NullPointerException
	* If the specified name is {@code null}.
	*/
	public static NetworkInterface getByName(String name) throws SocketException {
	if (name == null)
	throw new NullPointerException();
	return getByName0(name);
	}

	/**
	* Get a network interface given its index.
	*
	* @param index an integer, the index of the interface
	* @return the NetworkInterface obtained from its index, or {@code null} if
	* there is no interface with such an index on the system
	* @throws SocketException if an I/O error occurs.
	* @throws IllegalArgumentException if index has a negative value
	* @see #getIndex()
	* @since 1.7
	*/
	public static NetworkInterface getByIndex(int index) throws SocketException {
	if (index < 0)
	throw new IllegalArgumentException("Interface index can't be negative");
	return getByIndex0(index);
	}

	/**
	* Convenience method to search for a network interface that
	* has the specified Internet Protocol (IP) address bound to
	* it.
	* <p>
	* If the specified IP address is bound to multiple network
	* interfaces it is not defined which network interface is
	* returned.
	*
	* @param addr
	* The {@code InetAddress} to search with.
	*
	* @return A {@code NetworkInterface}
	* or {@code null} if there is no network interface
	* with the specified IP address.
	*
	* @throws SocketException
	* If an I/O error occurs.
	*
	* @throws NullPointerException
	* If the specified address is {@code null}.
	*/
	public static NetworkInterface getByInetAddress(InetAddress addr) throws SocketException {
	if (addr == null) {
	throw new NullPointerException();
	}
	if (!(addr instanceof Inet4Address \|\| addr instanceof Inet6Address)) {
	throw new IllegalArgumentException ("invalid address type");
	}
	return getByInetAddress0(addr);
	}

	/**
	* Returns an {@code Enumeration} of all the interfaces on this machine. The
	* {@code Enumeration} contains at least one element, possibly representing
	* a loopback interface that only supports communication between entities on
	* this machine.
	*
	* @apiNote this method can be used in combination with
	* {@link #getInetAddresses()} to obtain all IP addresses for this node
	*
	* @return an Enumeration of NetworkInterfaces found on this machine
	* @exception SocketException if an I/O error occurs,
	* or if the platform does not have at least one configured
	* network interface.
	* @see #networkInterfaces()
	*/
	public static Enumeration<NetworkInterface> getNetworkInterfaces()
	throws SocketException {
	NetworkInterface[] netifs = getAll();
	if (netifs != null && netifs.length > 0) {
	return enumerationFromArray(netifs);
	} else {
	throw new SocketException("No network interfaces configured");
	}
	}

	/**
	* Returns a {@code Stream} of all the interfaces on this machine. The
	* {@code Stream} contains at least one interface, possibly representing a
	* loopback interface that only supports communication between entities on
	* this machine.
	*
	* @apiNote this method can be used in combination with
	* {@link #inetAddresses()}} to obtain a stream of all IP addresses for
	* this node, for example:
	* <pre> {@code
	* Stream<InetAddress> addrs = NetworkInterface.networkInterfaces()
	* .flatMap(NetworkInterface::inetAddresses);
	* }</pre>
	*
	* @return a Stream of NetworkInterfaces found on this machine
	* @exception SocketException if an I/O error occurs,
	* or if the platform does not have at least one configured
	* network interface.
	* @since 9
	*/
	public static Stream<NetworkInterface> networkInterfaces()
	throws SocketException {
	NetworkInterface[] netifs = getAll();
	if (netifs != null && netifs.length > 0) {
	return streamFromArray(netifs);
	} else {
	throw new SocketException("No network interfaces configured");
	}
	}

	private static <T> Enumeration<T> enumerationFromArray(T[] a) {
	return new Enumeration<>() {
	int i = 0;

	@Override
	public T nextElement() {
	if (i < a.length) {
	return a[i++];
	} else {
	throw new NoSuchElementException();
	}
	}

	@Override
	public boolean hasMoreElements() {
	return i < a.length;
	}
	};
	}

	private static <T> Stream<T> streamFromArray(T[] a) {
	return StreamSupport.stream(
	Spliterators.spliterator(
	a,
	Spliterator.DISTINCT \| Spliterator.IMMUTABLE \| Spliterator.NONNULL),
	false);
	}

	private static native NetworkInterface[] getAll()
	throws SocketException;

	private static native NetworkInterface getByName0(String name)
	throws SocketException;

	private static native NetworkInterface getByIndex0(int index)
	throws SocketException;

	private static native NetworkInterface getByInetAddress0(InetAddress addr)
	throws SocketException;

	/**
	* Returns whether a network interface is up and running.
	*
	* @return {@code true} if the interface is up and running.
	* @exception SocketException if an I/O error occurs.
	* @since 1.6
	*/

	public boolean isUp() throws SocketException {
	return isUp0(name, index);
	}

	/**
	* Returns whether a network interface is a loopback interface.
	*
	* @return {@code true} if the interface is a loopback interface.
	* @exception SocketException if an I/O error occurs.
	* @since 1.6
	*/

	public boolean isLoopback() throws SocketException {
	return isLoopback0(name, index);
	}

	/**
	* Returns whether a network interface is a point to point interface.
	* A typical point to point interface would be a PPP connection through
	* a modem.
	*
	* @return {@code true} if the interface is a point to point
	* interface.
	* @exception SocketException if an I/O error occurs.
	* @since 1.6
	*/

	public boolean isPointToPoint() throws SocketException {
	return isP2P0(name, index);
	}

	/**
	* Returns whether a network interface supports multicasting or not.
	*
	* @return {@code true} if the interface supports Multicasting.
	* @exception SocketException if an I/O error occurs.
	* @since 1.6
	*/

	public boolean supportsMulticast() throws SocketException {
	return supportsMulticast0(name, index);
	}

	/**
	* Returns the hardware address (usually MAC) of the interface if it
	* has one and if it can be accessed given the current privileges.
	* If a security manager is set, then the caller must have
	* the permission {@link NetPermission}("getNetworkInformation").
	*
	* @return a byte array containing the address, or {@code null} if
	* the address doesn't exist, is not accessible or a security
	* manager is set and the caller does not have the permission
	* NetPermission("getNetworkInformation")
	*
	* @exception SocketException if an I/O error occurs.
	* @since 1.6
	*/
	public byte[] getHardwareAddress() throws SocketException {
	SecurityManager sec = System.getSecurityManager();
	if (sec != null) {
	try {
	sec.checkPermission(new NetPermission("getNetworkInformation"));
	} catch (SecurityException e) {
	if (!getInetAddresses().hasMoreElements()) {
	// don't have connect permission to any local address
	return null;
	}
	}
	}
	for (InetAddress addr : addrs) {
	if (addr instanceof Inet4Address) {
	return getMacAddr0(((Inet4Address)addr).getAddress(), name, index);
	}
	}
	return getMacAddr0(null, name, index);
	}

	/**
	* Returns the Maximum Transmission Unit (MTU) of this interface.
	*
	* @return the value of the MTU for that interface.
	* @exception SocketException if an I/O error occurs.
	* @since 1.6
	*/
	public int getMTU() throws SocketException {
	return getMTU0(name, index);
	}

	/**
	* Returns whether this interface is a virtual interface (also called
	* subinterface).
	* Virtual interfaces are, on some systems, interfaces created as a child
	* of a physical interface and given different settings (like address or
	* MTU). Usually the name of the interface will the name of the parent
	* followed by a colon (:) and a number identifying the child since there
	* can be several virtual interfaces attached to a single physical
	* interface.
	*
	* @return {@code true} if this interface is a virtual interface.
	* @since 1.6
	*/
	public boolean isVirtual() {
	return virtual;
	}

	private static native boolean isUp0(String name, int ind) throws SocketException;
	private static native boolean isLoopback0(String name, int ind) throws SocketException;
	private static native boolean supportsMulticast0(String name, int ind) throws SocketException;
	private static native boolean isP2P0(String name, int ind) throws SocketException;
	private static native byte[] getMacAddr0(byte[] inAddr, String name, int ind) throws SocketException;
	private static native int getMTU0(String name, int ind) throws SocketException;

	/**
	* Compares this object against the specified object.
	* The result is {@code true} if and only if the argument is
	* not {@code null} and it represents the same NetworkInterface
	* as this object.
	* <p>
	* Two instances of {@code NetworkInterface} represent the same
	* NetworkInterface if both name and addrs are the same for both.
	*
	* @param obj the object to compare against.
	* @return {@code true} if the objects are the same;
	* {@code false} otherwise.
	* @see java.net.InetAddress#getAddress()
	*/
	public boolean equals(Object obj) {
	if (!(obj instanceof NetworkInterface)) {
	return false;
	}
	NetworkInterface that = (NetworkInterface)obj;
	if (this.name != null ) {
	if (!this.name.equals(that.name)) {
	return false;
	}
	} else {
	if (that.name != null) {
	return false;
	}
	}

	if (this.addrs == null) {
	return that.addrs == null;
	} else if (that.addrs == null) {
	return false;
	}

	/* Both addrs not null. Compare number of addresses */

	if (this.addrs.length != that.addrs.length) {
	return false;
	}

	InetAddress[] thatAddrs = that.addrs;
	int count = thatAddrs.length;

	for (int i=0; i<count; i++) {
	boolean found = false;
	for (int j=0; j<count; j++) {
	if (addrs[i].equals(thatAddrs[j])) {
	found = true;
	break;
	}
	}
	if (!found) {
	return false;
	}
	}
	return true;
	}

	public int hashCode() {
	return name == null? 0: name.hashCode();
	}

	public String toString() {
	String result = "name:";
	result += name == null? "null": name;
	if (displayName != null) {
	result += " (" + displayName + ")";
	}
	return result;
	}

	private static native void init();

	/**
	* Returns the default network interface of this system
	*
	* @return the default interface
	*/
	static NetworkInterface getDefault() {
	return defaultInterface;
	}
	}

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