title: Is it possible to develop a custom API on Android? If so, how?
body: <p>Since Android is open-source, I am considering developing a custom API on it, mainly for implementing a web portal login module.</p>
  
  <p>Basic functions should include:</p>
  
  <ul>
  <li>Obtaining the wireless clients' MAC addresses;</li>
  <li>Redirecting their HTTP requests;</li>
  <li>Port/DNS filtering/blocking based on MAC addresses;</li>
  <li>And, wrapping all these functions into a custom API so that it may be
  provided to potential customers.</li>
  </ul>
  
  <p>Is it possible to develop such a custom API on Android? If so, how?</p>
  
  <p>Any reasonable comments are welcome. Thank you.</p>