java.net.NetworkInterface Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* Copyright (C) 2013 RoboVM AB
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package java.net;
import static libcore.io.OsConstants.*;
import java.io.FileDescriptor;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Enumeration;
import java.util.LinkedList;
import java.util.List;
import libcore.io.ErrnoException;
import libcore.io.IoUtils;
import libcore.io.Libcore;
/**
* This class is used to represent a network interface of the local device. An
* interface is defined by its address and a platform dependent name. The class
* provides methods to get all information about the available interfaces of the
* system or to identify the local interface of a joined multicast group.
*/
public final class NetworkInterface extends Object {
/*
* BugVM note: This class has been changed heavily to work on Darwin.
* The original class read all required info from /sys/class/net
* and /proc/net/if_inet6 and used no native code. Neither of those are
* available on Darwin so we need to call native code instead.
*/
// BugVM note: We need this to do things differently on DARWIN which
// has neither /sys/class/net nor /proc/net/if_inet6.
private static final boolean DARWIN;
static {
String osName = System.getProperty("os.name");
DARWIN = osName.contains("iOS") || osName.contains("Mac");
}
private final String name;
private final int interfaceIndex;
private final List interfaceAddresses;
private final List addresses;
private final List children = new LinkedList();
private NetworkInterface parent = null;
private NetworkInterface(String name, int interfaceIndex,
List addresses, List interfaceAddresses) {
this.name = name;
this.interfaceIndex = interfaceIndex;
this.addresses = addresses;
this.interfaceAddresses = interfaceAddresses;
}
static NetworkInterface forUnboundMulticastSocket() {
// This is what the RI returns for a MulticastSocket that hasn't been constrained
// to a specific interface.
return new NetworkInterface(null, -1,
Arrays.asList(Inet6Address.ANY), Collections.emptyList());
}
/**
* Returns the index for the network interface, or -1 if unknown.
* @since 1.7
*/
public int getIndex() {
return interfaceIndex;
}
/**
* Returns the name of this network interface (such as "eth0" or "lo").
*/
public String getName() {
return name;
}
/**
* Returns an enumeration of the addresses bound to this network interface.
*/
public Enumeration getInetAddresses() {
return Collections.enumeration(addresses);
}
/**
* Returns a human-readable name for this network interface. On Android, this is the same
* string as returned by {@link #getName}.
*/
public String getDisplayName() {
return name;
}
/**
* Returns the {@code NetworkInterface} corresponding to the named network interface, or null
* if no interface has this name.
*
* @throws SocketException if an error occurs.
* @throws NullPointerException if {@code interfaceName == null}.
*/
public static NetworkInterface getByName(String interfaceName) throws SocketException {
if (interfaceName == null) {
throw new NullPointerException("interfaceName == null");
}
int interfaceIndex = getInterfaceIndex(interfaceName);
if (interfaceIndex <= 0) {
return null;
}
List addresses = new ArrayList();
List interfaceAddresses = new ArrayList();
collectIpv6Addresses(interfaceName, interfaceIndex, addresses, interfaceAddresses);
collectIpv4Address(interfaceName, addresses, interfaceAddresses);
return new NetworkInterface(interfaceName, interfaceIndex, addresses, interfaceAddresses);
}
private static int ipv6NetmaskToPrefixLength(byte[] netmask) {
int prefixLength = 0;
int index = 0;
// Find the first byte != 0xff
while (index < netmask.length) {
int b = netmask[index++] & 0xff;
if (b != 0xff) {
break;
}
prefixLength += 8;
}
if (index == netmask.length) {
return prefixLength;
}
byte b = netmask[index];
// Find the first bit != 1 in b
for (int bit = 7; bit != 0; bit--) {
if ((b & (1 << bit)) == 0) {
break;
}
prefixLength++;
}
return prefixLength;
}
private static void collectIpv6Addresses(String interfaceName, int interfaceIndex,
List addresses, List interfaceAddresses) throws SocketException {
// BugVM note: This method used to read from /proc/net/if_inet6 which isn't available on
// Darwin.
byte[] bytes = getIpv6Addresses(interfaceName);
if (bytes != null) {
for (int i = 0; i < bytes.length; i += 32) {
byte[] addressBytes = new byte[16];
byte[] netmaskBytes = new byte[16];
System.arraycopy(bytes, i, addressBytes, 0, 16);
System.arraycopy(bytes, i + 16, netmaskBytes, 0, 16);
Inet6Address inet6Address = new Inet6Address(addressBytes, null, interfaceIndex);
addresses.add(inet6Address);
interfaceAddresses.add(new InterfaceAddress(inet6Address,
(short) ipv6NetmaskToPrefixLength(netmaskBytes)));
}
}
}
private static void collectIpv4Address(String interfaceName, List addresses,
List interfaceAddresses) throws SocketException {
// RoboVM note: This method used to use ioctl to probe a socket, this failed in various
// ways on Darwin.
byte[] bytes = getIpv4Addresses(interfaceName);
if (bytes != null) {
for (int i = 0; i < bytes.length; i += 12) {
Inet4Address address = new Inet4Address(
new byte[] { bytes[i + 0], bytes[i + 1], bytes[i + 2], bytes[i + 3] }, null);
Inet4Address netmask = new Inet4Address(
new byte[] { bytes[i + 4], bytes[i + 5], bytes[i + 6], bytes[i + 7] }, null);
Inet4Address broadcast = new Inet4Address(
new byte[] { bytes[i + 8], bytes[i + 9], bytes[i + 10], bytes[i + 11] }, null);
addresses.add(address);
interfaceAddresses.add(new InterfaceAddress(address, broadcast, netmask));
}
}
}
private static SocketException rethrowAsSocketException(Exception ex) throws SocketException {
SocketException result = new SocketException();
result.initCause(ex);
throw result;
}
/**
* Returns the {@code NetworkInterface} corresponding to the given address, or null if no
* interface has this address.
*
* @throws SocketException if an error occurs.
* @throws NullPointerException if {@code address == null}.
*/
public static NetworkInterface getByInetAddress(InetAddress address) throws SocketException {
if (address == null) {
throw new NullPointerException("address == null");
}
for (NetworkInterface networkInterface : getNetworkInterfacesList()) {
if (networkInterface.addresses.contains(address)) {
return networkInterface;
}
}
return null;
}
/**
* Returns the NetworkInterface corresponding to the given interface index, or null if no
* interface has this index.
*
* @throws SocketException if an error occurs.
* @since 1.7
*/
public static NetworkInterface getByIndex(int index) throws SocketException {
String name = Libcore.os.if_indextoname(index);
if (name == null) {
return null;
}
return NetworkInterface.getByName(name);
}
/**
* Gets a list of all network interfaces available on the local system or
* {@code null} if no interface is available.
*
* @return the list of {@code NetworkInterface} instances representing the
* available interfaces.
* @throws SocketException
* if an error occurs while getting the network interface
* information.
*/
public static Enumeration getNetworkInterfaces() throws SocketException {
return Collections.enumeration(getNetworkInterfacesList());
}
/**
* Returns an array of all available interface names.
* Added in BugVM.
*/
private static native String[] getInterfaceNames();
/**
* Returns the index of the interface with specified name or 0 if not found.
* Added in BugVM.
*/
private static native int getInterfaceIndex(String interfaceName);
/**
* Uses getifaddrs() to retrieve the IPv6 addresses of the interface with
* the specified name. Returns null if the interface has no
* IPv6 addresses. Otherwise a byte array is returned with address 1 at
* index 0 and its netmask at index 16, address 2 at index 32 and its
* netmask at index 48, etc.
* Added in BugVM.
*/
private static native byte[] getIpv6Addresses(String interfaceName);
/**
* Uses getifaddrs() to retrieve the IPv4 addresses of the interface with
* the specified name. Returns null if the interface has no
* IPv4 addresses. Otherwise a byte array is returned with address 1 at
* index 0 and its netmask at index 4 and its broadcast address at index 8,
* address 2 at index 12 and its netmask at index 16 and its broadcast address
* at index 20, etc.
* Added in BugVM.
*/
private static native byte[] getIpv4Addresses(String interfaceName);
/** * Uses getifaddrs() to retrieve the MAC address of the interface with the
* specified name.
* Added in BugVM.
*/
private static native byte[] getHardwareAddress(String interfaceName);
/**
* Returns the flags of the specified interface using ioctl(SIOCGIFFLAGS).
* Added in BugVM.
*/
private static native int getFlags(String interfaceName);
/**
* Returns the MTU of the specified interface using ioctl(SIOCGIFMTU).
* Added in BugVM.
*/
private static native int getMTU(String interfaceName);
@FindBugsSuppressWarnings("DMI_HARDCODED_ABSOLUTE_FILENAME")
private static List getNetworkInterfacesList() throws SocketException {
String[] interfaceNames = getInterfaceNames();
NetworkInterface[] interfaces = new NetworkInterface[interfaceNames.length];
boolean[] done = new boolean[interfaces.length];
for (int i = 0; i < interfaceNames.length; ++i) {
interfaces[i] = NetworkInterface.getByName(interfaceNames[i]);
// http://b/5833739: getByName can return null if the interface went away between our
// readdir(2) and our stat(2), so mark interfaces that disappeared as 'done'.
if (interfaces[i] == null) {
done[i] = true;
}
}
List result = new ArrayList();
for (int counter = 0; counter < interfaces.length; counter++) {
// If this interface has been dealt with already, continue.
if (done[counter]) {
continue;
}
// Checks whether the following interfaces are children.
for (int counter2 = counter; counter2 < interfaces.length; counter2++) {
if (done[counter2]) {
continue;
}
if (interfaces[counter2].name.startsWith(interfaces[counter].name + ":")) {
interfaces[counter].children.add(interfaces[counter2]);
interfaces[counter2].parent = interfaces[counter];
interfaces[counter].addresses.addAll(interfaces[counter2].addresses);
done[counter2] = true;
}
}
result.add(interfaces[counter]);
done[counter] = true;
}
return result;
}
/**
* Compares the specified object to this {@code NetworkInterface} and
* returns whether they are equal or not. The object must be an instance of
* {@code NetworkInterface} with the same name, display name, and list
* of interface addresses.
*
* @param obj
* the object to compare with this instance.
* @return {@code true} if the specified object is equal to this {@code
* NetworkInterface}, {@code false} otherwise.
* @see #hashCode()
*/
@Override
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof NetworkInterface)) {
return false;
}
NetworkInterface rhs = (NetworkInterface) obj;
// TODO: should the order of the addresses matter (we use List.equals)?
return interfaceIndex == rhs.interfaceIndex &&
name.equals(rhs.name) &&
addresses.equals(rhs.addresses);
}
/**
* Returns the hash code for this {@code NetworkInterface}. Since the
* name should be unique for each network interface the hash code is
* generated using the name.
*/
@Override public int hashCode() {
return name.hashCode();
}
/**
* Returns a string containing details of this network interface.
* The exact format is deliberately unspecified. Callers that require a specific
* format should build a string themselves, using this class' accessor methods.
*/
@Override public String toString() {
StringBuilder sb = new StringBuilder(25);
sb.append("[");
sb.append(name);
sb.append("][");
sb.append(interfaceIndex);
sb.append("]");
for (InetAddress address : addresses) {
sb.append("[");
sb.append(address.toString());
sb.append("]");
}
return sb.toString();
}
/**
* Returns a List of the InterfaceAddresses for this network interface.
* @since 1.6
*/
public List getInterfaceAddresses() {
return Collections.unmodifiableList(interfaceAddresses);
}
/**
* Returns an enumeration of all the sub-interfaces of this network interface.
* Sub-interfaces are also known as virtual interfaces.
*
* For example, {@code eth0:1} would be a sub-interface of {@code eth0}.
*
* @return an Enumeration of all the sub-interfaces of this network interface
* @since 1.6
*/
public Enumeration getSubInterfaces() {
return Collections.enumeration(children);
}
/**
* Returns the parent NetworkInterface of this interface if this is a
* sub-interface, or null if it's a physical (non virtual) interface.
*
* @return the NetworkInterface this interface is attached to.
* @since 1.6
*/
public NetworkInterface getParent() {
return parent;
}
/**
* Returns true if this network interface is up.
*
* @return true if the interface is up.
* @throws SocketException if an I/O error occurs.
* @since 1.6
*/
public boolean isUp() throws SocketException {
return hasFlag(IFF_UP);
}
/**
* Returns true if this network interface is a loopback interface.
*
* @return true if the interface is a loopback interface.
* @throws SocketException if an I/O error occurs.
* @since 1.6
*/
public boolean isLoopback() throws SocketException {
return hasFlag(IFF_LOOPBACK);
}
/**
* Returns true if this network interface is a point-to-point interface.
* (For example, a PPP connection using a modem.)
*
* @return true if the interface is point-to-point.
* @throws SocketException if an I/O error occurs.
* @since 1.6
*/
public boolean isPointToPoint() throws SocketException {
return hasFlag(IFF_POINTOPOINT);
}
/**
* Returns true if this network interface supports multicast.
*
* @throws SocketException if an I/O error occurs.
* @since 1.6
*/
public boolean supportsMulticast() throws SocketException {
return hasFlag(IFF_MULTICAST);
}
private boolean hasFlag(int mask) throws SocketException {
// BugVM note: Changed to call native code instead of reading from /sys/class/net
int flags = getFlags(name);
return (flags & mask) != 0;
}
/**
* Returns the hardware address of the interface, if it has one, or null otherwise.
*
* @throws SocketException if an I/O error occurs.
* @since 1.6
*/
public byte[] getHardwareAddress() throws SocketException {
// BugVM note: Changed to call native code instead of reading from /sys/class/net
return getHardwareAddress(name);
}
/**
* Returns the Maximum Transmission Unit (MTU) of this interface.
*
* @return the value of the MTU for the interface.
* @throws SocketException if an I/O error occurs.
* @since 1.6
*/
public int getMTU() throws SocketException {
// BugVM note: Changed to call native code instead of reading from /sys/class/net
return getMTU(name);
}
/**
* Returns true if this interface is a virtual interface (also called
* a sub-interface). 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 true if this interface is a virtual interface.
* @since 1.6
*/
public boolean isVirtual() {
return parent != null;
}
}