Programmatically getting the gateway and subnet mask details

Question

How can I get gateway and subnet mask details in Android?

Answer 1

I have found a class called DhcpInfo within the android.net package. It has some public variables that stores the values of current Network parameters. But the problem is they return the value in integer converted from 8Bit shifted binary.

Sample Image Describing thee Scenario:

****Here is a sample code:**

**java file:****

package com.schogini.dhcp;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.widget.TextView;
import android.net.*;
import android.net.wifi.WifiManager;

public class dhcpInfo extends Activity {
    public String   s_dns1 ;
    public String   s_dns2;     
    public String   s_gateway;  
    public String   s_ipAddress;    
    public String   s_leaseDuration;    
    public String   s_netmask;  
    public String   s_serverAddress;
    TextView info;
    DhcpInfo d;
    WifiManager wifii;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        wifii= (WifiManager) getSystemService(Context.WIFI_SERVICE);
        d=wifii.getDhcpInfo();

        s_dns1="DNS 1: "+String.valueOf(d.dns1);
        s_dns2="DNS 2: "+String.valueOf(d.dns2);    
        s_gateway="Default Gateway: "+String.valueOf(d.gateway);    
        s_ipAddress="IP Address: "+String.valueOf(d.ipAddress); 
        s_leaseDuration="Lease Time: "+String.valueOf(d.leaseDuration);     
        s_netmask="Subnet Mask: "+String.valueOf(d.netmask);    
        s_serverAddress="Server IP: "+String.valueOf(d.serverAddress);

        //dispaly them
        info= (TextView) findViewById(R.id.infolbl);
        info.setText("Network Info\n"+s_dns1+"\n"+s_dns2+"\n"+s_gateway+"\n"+s_ipAddress+"\n"+s_leaseDuration+"\n"+s_netmask+"\n"+s_serverAddress);
    }
}

xml Coding:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.schogini.dhcp"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-sdk android:minSdkVersion="4" />

    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".dhcpInfo"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />  
</manifest>

I tried converting the integer value to its equivalent but i couldn't. If you do so you can post back.. Bye..

UPDATE: Some how managed to convert the IP to v4 Format from the integer form Conversion to IPv4 Format:

public String intToIp(int i) {

   return ((i >> 24 ) & 0xFF ) + "." +
               ((i >> 16 ) & 0xFF) + "." +
               ((i >> 8 ) & 0xFF) + "." +
               ( i & 0xFF) ;
}

IMAGE Courtesy: http://www.bennadel.com/blog/1830-Converting-IP-Addresses-To-And-From-Integer-Values-With-ColdFusion.htm

Answer 2

Formatter.formatIpAddress(int) is deprecated, and we dont want to use deprecated methods do we?

AndroidKid's version of this is somehow reversed, but this should fix it:

public String intToIp(int addr) {
    return  ((addr & 0xFF) + "." + 
            ((addr >>>= 8) & 0xFF) + "." + 
            ((addr >>>= 8) & 0xFF) + "." + 
            ((addr >>>= 8) & 0xFF));
}

Source: http://www.devdaily.com/java/jwarehouse/android/core/java/android/net/DhcpInfo.java.shtml

Answer 3

This is an old Thread, but I found the official function used by android API (package android.net.NetworkUtils):

/**
 * Convert a IPv4 address from an integer to an InetAddress.
 * @param hostAddress an int corresponding to the IPv4 address in network byte order
 */
public static InetAddress intToInetAddress(int hostAddress) {
    byte[] addressBytes = { (byte)(0xff & hostAddress),
                            (byte)(0xff & (hostAddress >> 8)),
                            (byte)(0xff & (hostAddress >> 16)),
                            (byte)(0xff & (hostAddress >> 24)) };

    try {
       return InetAddress.getByAddress(addressBytes);
    } catch (UnknownHostException e) {
       throw new AssertionError();
    }
}

And once you have InetAddress you can get the formatted String this way:

intToInetAddress(d.gateway).getHostAddress()

Answer 4

to format the ip, try using:

import android.text.format.Formatter;

public String FormatIP(int IpAddress)
{
    return Formatter.formatIpAddress(IpAddress);
}

Answer 5

Use Formatter.formatIpAddress(mask); mask is your int.

String maskk = Formatter.formatIpAddress(mask);

Answer 6

This version works with any Network (Wifi/Cell). Returns V4 and V6.

/**
 * Returns the set of all gateways<V4 & V6> for any Network
 *
 */
fun getGatewaySet(network:Network, context:Context):MutableSet<InetAddress> {
    val connectivityManager = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
    connectivityManager.getLinkProperties(network)?.routes?.let {
        //Saw dupes on my device, so use a set
        val set = mutableSetOf<InetAddress>()
        for (routeInfo in it) {
            routeInfo?.gateway?.let { inetAddress ->
                //If comes from AOSP isGateway() - requires API 29
                if (!inetAddress.isAnyLocalAddress) {
                    set.add(inetAddress)
                }
            }
        }
        return set
    }
    return Collections.EMPTY_SET as MutableSet<InetAddress>
}

Answer 7

Instead of getting 255.255.255.0, just change the order in return ;) So you will be able to get in the right order...

public String intToIp(int i) {

   return (i & 0xFF) + "." +
               ((i >> 8 ) & 0xFF) + "." +
               ((i >> 16 ) & 0xFF) + "." +
               ((i >> 24 ) & 0xFF) ;
}

Answer 8

Although old, works like a charm.

tvGateway.setText(Formatter.formatIpAddress(dhcpInfo.gateway));