title: Get ethernet router MAC address in android
body: <p>I use this function to get device MAC address</p>
  
  <pre><code>public static String getMacAddress(){
          try {
              return loadFileAsString("/sys/class/net/eth0/address")
                      .toUpperCase().substring(0, 17);
          } catch (IOException e) {
              e.printStackTrace();
              return null;
          }
      }
  </code></pre>
  
  <p>Now I need to also get mac address of router this ethernet is connected to. How can I do that?</p>