WiFi Information Extraction Java

Hello everyone, I was recently involved in a wireless networking project where we had to develop a student response system. In that I had to extract certain WiFi related information such as list of available SSIDs, connected SSID, IP address and Subnet Mask

Java doesn’t allows us to directly get that low level information. Therefore I had run command line and run netsh commands inside java an extract that information. Following is the class I implemented for this. Please note that this only works on windows.

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 *
 * @author Rajind
 */
public class Extractor {
    
    public static String NOT_SET = "NOT_SET";
    
    public static boolean isEnabled(){
        try {
            String state;
            ProcessBuilder builder = new ProcessBuilder(
                    "cmd.exe", "/c", "netsh interface show interface \"Wi-Fi\"");
            builder.redirectErrorStream(true);
            Process p = builder.start();
            BufferedReader r = new BufferedReader(new InputStreamReader(p.getInputStream()));
            String line;
            while ((line = r.readLine())!=null) {
                //line = r.readLine();
                if (line.contains("Administrative state")){
                    state = line.split("\\s+")[3];
                    //System.out.println(state);
                    state = state.toLowerCase();
                    if(state.equals("enabled")){
                        return true;
                    }else{
                        return false;
                    }
                }
            }
        } catch (IOException ex) {
            Logger.getLogger(Extractor.class.getName()).log(Level.SEVERE, null, ex);
        }
        return false;
    }
    
    public static boolean isConnected(){
        try {
            String state;
            ProcessBuilder builder = new ProcessBuilder(
                    "cmd.exe", "/c", "netsh interface show interface \"Wi-Fi\"");
            builder.redirectErrorStream(true);
            Process p = builder.start();
            BufferedReader r = new BufferedReader(new InputStreamReader(p.getInputStream()));
            String line;
            while ((line = r.readLine())!=null) {
                //line = r.readLine();
                if (line.contains("Connect state")){
                    state = line.split("\\s+")[3];
//                    System.out.println(state);
                    state = state.toLowerCase();
                    if(state.equals("connected")){
                        return true;
                    }else{
                        return false;
                    }
                }
            }
        } catch (IOException ex) {
            Logger.getLogger(Extractor.class.getName()).log(Level.SEVERE, null, ex);
        }
        return false;
    }
    
    public static String getConnectedSSID(){
        String ssid = NOT_SET;
        try {
            ProcessBuilder builder = new ProcessBuilder(
                    "cmd.exe", "/c", "netsh wlan show interfaces");
            builder.redirectErrorStream(true);
            Process p = builder.start();
            BufferedReader r = new BufferedReader(new InputStreamReader(p.getInputStream()));
            String line;
            while ((line = r.readLine())!=null) {
                //line = r.readLine();
                if (line.contains("SSID")){
                    ssid = line.split("\\s+")[3];
//                    System.out.println(ssid);
                    return ssid;
                }
            }
        } catch (IOException ex) {
            Logger.getLogger(Extractor.class.getName()).log(Level.SEVERE, null, ex);
        }
        return ssid;
    }
    
    public static String[] getListOfSSIDs(){
        String [] ssid_List;
        String ssid;
        ArrayList<String> arr = new ArrayList<>();
        try {
            ProcessBuilder builder = new ProcessBuilder(
                    "cmd.exe", "/c", "netsh wlan show networks");
            builder.redirectErrorStream(true);
            Process p = builder.start();
            BufferedReader r = new BufferedReader(new InputStreamReader(p.getInputStream()));
            String line;
            while ((line = r.readLine())!=null) {
                //line = r.readLine();
                if (line.contains("SSID")){
                    ssid = line.split("\\s+")[3];
                    //System.out.println(ssid);
                    arr.add(ssid);
                }
            }
        } catch (IOException ex) {
            Logger.getLogger(Extractor.class.getName()).log(Level.SEVERE, null, ex);
        }
        ssid_List = new String[arr.size()];
        arr.toArray(ssid_List);
        return ssid_List;
    }
    
    public static String getIP(){
        String ip = NOT_SET; 
        try {
            ProcessBuilder builder = new ProcessBuilder(
                    "cmd.exe", "/c", "netsh interface ip show addresses \"Wi-Fi\"");
            builder.redirectErrorStream(true);
            Process p = builder.start();
            BufferedReader r = new BufferedReader(new InputStreamReader(p.getInputStream()));
            String line;
            while ((line = r.readLine())!=null) {
                //line = r.readLine();
                if (line.contains("IP Address")){
                    ip = line.split("\\s+")[3];
                    //System.out.println(ip);
                    return ip;
                }
            }
        } catch (IOException ex) {
            Logger.getLogger(Extractor.class.getName()).log(Level.SEVERE, null, ex);
        }
        return ip;
    }
    
    public static String getSubnetMask(){
        String sb = NOT_SET; 
        try {
            ProcessBuilder builder = new ProcessBuilder(
                    "cmd.exe", "/c", "netsh interface ip show addresses \"Wi-Fi\"");
            builder.redirectErrorStream(true);
            Process p = builder.start();
            BufferedReader r = new BufferedReader(new InputStreamReader(p.getInputStream()));
            String line;
            while ((line = r.readLine())!=null) {
                //line = r.readLine();
                if (line.contains("Subnet Prefix")){
                    sb = line.split("\\s+")[5];
                    sb = sb.substring(0, sb.length() - 1);
                    //System.out.println(sb);
                    return sb;
                }
            }
        } catch (IOException ex) {
            Logger.getLogger(Extractor.class.getName()).log(Level.SEVERE, null, ex);
        }
        return sb;
    }
    
    public static String getBroadcast(){
        String subnetMask = getSubnetMask();
        String ip = getIP();
        
        String []arrSubnetMask = subnetMask.split("\\.");
        String []arrIP = ip.split("\\.");
        int []networkAddress = new int[4];
        int [] broadcastAddress = new int[4];
        
        String broadcast = "";
        
        for(int i=0; i< 4; i++){
            networkAddress[i] =  Integer.parseInt(arrIP[i]) & Integer.parseInt(arrSubnetMask[i]);
            //System.out.println(networkAddress[i]);
        }
        
        for(int i=0; i< 4; i++){
            //broadcastAddress[i] =  networkAddress[i] | (~Integer.parseInt(arrSubnetMask[i]) & 0xff);
            //System.out.println(broadcastAddress[i]);
            broadcast = broadcast + "." + (networkAddress[i] | (~Integer.parseInt(arrSubnetMask[i]) & 0xff));
        }
        
//        System.out.println(broadcast.substring(1));
        
        //mask AND ip you get network address
        //Invert Mask OR Network Address you get broadcast
        
        return broadcast.substring(1);
    }
}

~Rajind Ruparathna