Android example source code file (NetworkUtils.java)

This example Android source code file (NetworkUtils.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, dhcpinfo, inet4address, inet6address, inetaddress, ipv4, ipv6, net, network, networkutils, string, tag, util, utilities, utils

The NetworkUtils.java Android example source code

/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * 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 android.net;

import java.net.InetAddress;
import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.UnknownHostException;

import android.util.Log;

/**
 * Native methods for managing network interfaces.
 *
 * {@hide}
 */
public class NetworkUtils {

    private static final String TAG = "NetworkUtils";

    /** Bring the named network interface up. */
    public native static int enableInterface(String interfaceName);

    /** Bring the named network interface down. */
    public native static int disableInterface(String interfaceName);

    /**
     * Add a route to the routing table.
     *
     * @param interfaceName the interface to route through.
     * @param dst the network or host to route to. May be IPv4 or IPv6, e.g.
     * "0.0.0.0" or "2001:4860::".
     * @param prefixLength the prefix length of the route.
     * @param gw the gateway to use, e.g., "192.168.251.1". If null,
     * indicates a directly-connected route.
     */
    public native static int addRoute(String interfaceName, String dst,
          int prefixLength, String gw);

    /** Return the gateway address for the default route for the named interface. */
    public native static int getDefaultRoute(String interfaceName);

    /** Remove host routes that uses the named interface. */
    public native static int removeHostRoutes(String interfaceName);

    /** Remove the default route for the named interface. */
    public native static int removeDefaultRoute(String interfaceName);

    /** Reset any sockets that are connected via the named interface. */
    public native static int resetConnections(String interfaceName);

    /**
     * Start the DHCP client daemon, in order to have it request addresses
     * for the named interface, and then configure the interface with those
     * addresses. This call blocks until it obtains a result (either success
     * or failure) from the daemon.
     * @param interfaceName the name of the interface to configure
     * @param ipInfo if the request succeeds, this object is filled in with
     * the IP address information.
     * @return {@code true} for success, {@code false} for failure
     */
    public native static boolean runDhcp(String interfaceName, DhcpInfo ipInfo);

    /**
     * Shut down the DHCP client daemon.
     * @param interfaceName the name of the interface for which the daemon
     * should be stopped
     * @return {@code true} for success, {@code false} for failure
     */
    public native static boolean stopDhcp(String interfaceName);

    /**
     * Release the current DHCP lease.
     * @param interfaceName the name of the interface for which the lease should
     * be released
     * @return {@code true} for success, {@code false} for failure
     */
    public native static boolean releaseDhcpLease(String interfaceName);

    /**
     * Return the last DHCP-related error message that was recorded.
     * <p/>NOTE: This string is not localized, but currently it is only
     * used in logging.
     * @return the most recent error message, if any
     */
    public native static String getDhcpError();

    /**
     * When static IP configuration has been specified, configure the network
     * interface according to the values supplied.
     * @param interfaceName the name of the interface to configure
     * @param ipInfo the IP address, default gateway, and DNS server addresses
     * with which to configure the interface.
     * @return {@code true} for success, {@code false} for failure
     */
    public static boolean configureInterface(String interfaceName, DhcpInfo ipInfo) {
        return configureNative(interfaceName,
            ipInfo.ipAddress,
            ipInfo.netmask,
            ipInfo.gateway,
            ipInfo.dns1,
            ipInfo.dns2);
    }

    private native static boolean configureNative(
        String interfaceName, int ipAddress, int netmask, int gateway, int dns1, int dns2);

    /**
     * Convert a IPv4 address from an integer to an InetAddress.
     * @param hostAddr is an Int corresponding to the IPv4 address in network byte order
     * @return the IP address as an {@code InetAddress}, returns null if
     * unable to convert or if the int is an invalid address.
     */
    public static InetAddress intToInetAddress(int hostAddress) {
        InetAddress inetAddress;
        byte[] addressBytes = { (byte)(0xff & hostAddress),
                                (byte)(0xff & (hostAddress >> 8)),
                                (byte)(0xff & (hostAddress >> 16)),
                                (byte)(0xff & (hostAddress >> 24)) };

        try {
           inetAddress = InetAddress.getByAddress(addressBytes);
        } catch(UnknownHostException e) {
           return null;
        }

        return inetAddress;
    }

    /**
     * Add a default route through the specified gateway.
     * @param interfaceName interface on which the route should be added
     * @param gw the IP address of the gateway to which the route is desired,
     * @return {@code true} on success, {@code false} on failure
     */
    public static boolean addDefaultRoute(String interfaceName, InetAddress gw) {
        String dstStr;
        String gwStr = gw.getHostAddress();

        if (gw instanceof Inet4Address) {
            dstStr = "0.0.0.0";
        } else if (gw instanceof Inet6Address) {
            dstStr = "::";
        } else {
            Log.w(TAG, "addDefaultRoute failure: address is neither IPv4 nor IPv6" +
                       "(" + gwStr + ")");
            return false;
        }
        return addRoute(interfaceName, dstStr, 0, gwStr) == 0;
    }

    /**
     * Add a host route.
     * @param interfaceName interface on which the route should be added
     * @param dst the IP address of the host to which the route is desired,
     * this should not be null.
     * @param gw the IP address of the gateway to which the route is desired,
     * if null, indicates a directly-connected route.
     * @return {@code true} on success, {@code false} on failure
     */
    public static boolean addHostRoute(String interfaceName, InetAddress dst,
          InetAddress gw) {
        if (dst == null) {
            Log.w(TAG, "addHostRoute: dst should not be null");
            return false;
        }

        int prefixLength;
        String dstStr = dst.getHostAddress();
        String gwStr = (gw != null) ? gw.getHostAddress() : null;

        if (dst instanceof Inet4Address) {
            prefixLength = 32;
        } else if (dst instanceof Inet6Address) {
            prefixLength = 128;
        } else {
            Log.w(TAG, "addHostRoute failure: address is neither IPv4 nor IPv6" +
                       "(" + dst + ")");
            return false;
        }
        return addRoute(interfaceName, dstStr, prefixLength, gwStr) == 0;
    }
}