Android get IP and Mac addresses from local network

Question

I am trying to do an application which works quite similar to Fing. I would like to get the IP addresses and the Mac address from all devices connected to the same network.

I tried to use a nmap command (used in Linux) but unfortunately it doesn't work. Anybody knows how could I get this information?

EDIT:

The Nmap address which I use is the following.

try {
        StringBuffer output = new StringBuffer();
        Process proc = Runtime.getRuntime().exec("sudo nmap -sP 192.168.1.0/24");
        proc.waitFor();
         BufferedReader reader = new BufferedReader(new InputStreamReader(proc.getInputStream()));
         String line = "";
         while ((line = reader.readLine())!= null) {
             output.append(line + "\n");
          }
        Log.e("RESULT",output.toString());
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (InterruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

And then it throws an Exception:

07-30 17:51:55.789: W/System.err(25319): java.io.IOException: Error running exec(). Command: [sudo, nmap, -sP, 192.168.1.0/24] Working Directory: null Environment: null
07-30 17:51:55.789: W/System.err(25319):    at java.lang.ProcessManager.exec(ProcessManager.java:224)

Answer 1

// AndroidManifest.xml permissions
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

// test functions
Utils.getMACAddress("wlan0");
Utils.getMACAddress("eth0");
Utils.getIPAddress(true); // IPv4
Utils.getIPAddress(false); // IPv6 
mport java.io.*;
import java.net.*;
import java.util.*; 
import org.apache.http.conn.util.InetAddressUtils;

public class Utils {

/**
 * Convert byte array to hex string
 * @param bytes
 * @return
     */
    public static String bytesToHex(byte[] bytes) {
        StringBuilder sbuf = new StringBuilder();
        for(int idx=0; idx < bytes.length; idx++) {
            int intVal = bytes[idx] & 0xff;
            if (intVal < 0x10) sbuf.append("0");
            sbuf.append(Integer.toHexString(intVal).toUpperCase());
        }
        return sbuf.toString();
    }




/**
     * Get utf8 byte array.
     * @param str
     * @return  array of NULL if error was found
         */
        public static byte[] getUTF8Bytes(String str) {
            try { return str.getBytes("UTF-8"); } catch (Exception ex) { return null; }
        }
/**
 * Load UTF8withBOM or any ansi text file.
 * @param filename
 * @return  
 * @throws java.io.IOException
     */
    public static String loadFileAsString(String filename) throws java.io.IOException {
        final int BUFLEN=1024;
        BufferedInputStream is = new BufferedInputStream(new FileInputStream(filename), BUFLEN);
        try {
            ByteArrayOutputStream baos = new ByteArrayOutputStream(BUFLEN);
            byte[] bytes = new byte[BUFLEN];
            boolean isUTF8=false;
            int read,count=0;           
            while((read=is.read(bytes)) != -1) {
                if (count==0 && bytes[0]==(byte)0xEF && bytes[1]==(byte)0xBB && bytes[2]==(byte)0xBF ) {
                    isUTF8=true;
                    baos.write(bytes, 3, read-3); // drop UTF8 bom marker
                } else {
                    baos.write(bytes, 0, read);
                }
                count+=read;
            }
            return isUTF8 ? new String(baos.toByteArray(), "UTF-8") : new String(baos.toByteArray());
        } finally {
            try{ is.close(); } catch(Exception ex){} 
        }
    }


/**
 * Returns MAC address of the given interface name.
 * @param interfaceName eth0, wlan0 or NULL=use first interface 
 * @return  mac address or empty string
     /
    public static String getMACAddress(String interfaceName) {
        try {
            List&lt;NetworkInterface&gt; interfaces = Collections.list(NetworkInterface.getNetworkInterfaces());
            for (NetworkInterface intf : interfaces) {
                if (interfaceName != null) {
                    if (!intf.getName().equalsIgnoreCase(interfaceName)) continue;
                }
                byte[] mac = intf.getHardwareAddress();
                if (mac==null) return "";
                StringBuilder buf = new StringBuilder();
                for (int idx=0; idx&lt;mac.length; idx++)
                    buf.append(String.format("%02X:", mac[idx]));       
                if (buf.length()>0) buf.deleteCharAt(buf.length()-1);
                return buf.toString();
            }
        } catch (Exception ex) { } // for now eat exceptions
        return "";
        /*try {
            // this is so Linux hack
            return loadFileAsString("/sys/class/net/" +interfaceName + "/address").toUpperCase().trim();
        } catch (IOException ex) {
            return null;
        }/
    }


/**
 * Get IP address from first non-localhost interface
 * @param ipv4  true=return ipv4, false=return ipv6
 * @return  address or empty string
     */
    public static String getIPAddress(boolean useIPv4) {
        try {
            List&lt;NetworkInterface&gt; interfaces = Collections.list(NetworkInterface.getNetworkInterfaces());
            for (NetworkInterface intf : interfaces) {
                List&lt;InetAddress&gt; addrs = Collections.list(intf.getInetAddresses());
                for (InetAddress addr : addrs) {
                    if (!addr.isLoopbackAddress()) {
                        String sAddr = addr.getHostAddress().toUpperCase();
                        boolean isIPv4 = InetAddressUtils.isIPv4Address(sAddr); 
                        if (useIPv4) {
                            if (isIPv4) 
                                return sAddr;
                        } else {
                            if (!isIPv4) {
                                int delim = sAddr.indexOf('%'); // drop ip6 port suffix
                                return delim&lt;0 ? sAddr : sAddr.substring(0, delim);
                            }
                        }
                    }
                }
            }
        } catch (Exception ex) { } // for now eat exceptions
        return "";
    }

}

https://stackoverflow.com/a/13007325