Android Open Source - ACM_Pi_Cloud Server Name Indicator

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License

The source code is released under:

MIT License

Java Source Code

/* ownCloud Android Library is available under MIT license
 *   Copyright (C) 2014 ownCloud Inc./*ww w  .  j a v  a  2 s  .com*/
 *   
 *   Permission is hereby granted, free of charge, to any person obtaining a copy
 *   of this software and associated documentation files (the "Software"), to deal
 *   in the Software without restriction, including without limitation the rights
 *   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 *   copies of the Software, and to permit persons to whom the Software is
 *   furnished to do so, subject to the following conditions:
 *   
 *   The above copyright notice and this permission notice shall be included in
 *   all copies or substantial portions of the Software.
 *   
 *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
 *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
 *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 
 *   BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 
 *   ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 
 *   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 *   THE SOFTWARE.
 *
 */

package com.owncloud.android.lib.common.network;

import java.lang.ref.WeakReference;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.concurrent.atomic.AtomicReference;

import javax.net.ssl.SSLSocket;

import android.util.Log;


/**
 * Enables the support of Server Name Indication if existing 
 * in the underlying network implementation.
 * 
 * Build as a singleton.
 * 
 * @author David A. Velasco
 */
public class ServerNameIndicator {
  
  private static final String TAG = ServerNameIndicator.class.getSimpleName();
  
  private static final AtomicReference<ServerNameIndicator> mSingleInstance = new AtomicReference<ServerNameIndicator>();
  
  private static final String METHOD_NAME = "setHostname";
  
  private final WeakReference<Class<?>> mSSLSocketClassRef;
  private final WeakReference<Method> mSetHostnameMethodRef;
  
  
  /**
   * Private constructor, class is a singleton.
   * 
   * @param sslSocketClass    Underlying implementation class of {@link SSLSocket} used to connect with the server. 
   * @param setHostnameMethod    Name of the method to call to enable the SNI support.
   */
  private ServerNameIndicator(Class<?> sslSocketClass, Method setHostnameMethod) {
    mSSLSocketClassRef = new WeakReference<Class<?>>(sslSocketClass);
    mSetHostnameMethodRef = (setHostnameMethod == null) ? null : new WeakReference<Method>(setHostnameMethod);
  }
  
  
  /**
   * Calls the {@code #setHostname(String)} method of the underlying implementation 
   * of {@link SSLSocket} if exists.
   * 
   * Creates and initializes the single instance of the class when needed
   *
   * @param hostname     The name of the server host of interest.
   * @param sslSocket   Client socket to connect with the server.
   */
  public static void setServerNameIndication(String hostname, SSLSocket sslSocket) {
    final Method setHostnameMethod = getMethod(sslSocket);
    if (setHostnameMethod != null) {
      try {
        setHostnameMethod.invoke(sslSocket, hostname);
        Log.i(TAG, "SNI done, hostname: " + hostname);
        
      } catch (IllegalArgumentException e) {
        Log.e(TAG, "Call to SSLSocket#setHost(String) failed ", e);
        
      } catch (IllegalAccessException e) {
        Log.e(TAG, "Call to SSLSocket#setHost(String) failed ", e);
        
      } catch (InvocationTargetException e) {
        Log.e(TAG, "Call to SSLSocket#setHost(String) failed ", e);
      }
    } else {
      Log.i(TAG, "SNI not supported");
    }
  }

  
  /**
   * Gets the method to invoke trying to minimize the effective 
   * application of reflection.
   * 
   * @param   sslSocket    Instance of the SSL socket to use in connection with server.
   * @return          Method to call to indicate the server name of interest to the server.
   */
  private static Method getMethod(SSLSocket sslSocket) {
    final Class<?> sslSocketClass = sslSocket.getClass();
    final ServerNameIndicator instance = mSingleInstance.get();
    if (instance == null) {
      return initFrom(sslSocketClass);
      
    } else if (instance.mSSLSocketClassRef.get() != sslSocketClass) {
      // the underlying class changed
      return initFrom(sslSocketClass);
        
    } else if (instance.mSetHostnameMethodRef == null) {
      // SNI not supported
      return null;
        
    } else {
      final Method cachedSetHostnameMethod = instance.mSetHostnameMethodRef.get();
      return (cachedSetHostnameMethod == null) ? initFrom(sslSocketClass) : cachedSetHostnameMethod;
    }
  }


  /**
   * Singleton initializer.
   * 
   * Uses reflection to extract and 'cache' the method to invoke to indicate the desited host name to the server side.
   *  
   * @param   sslSocketClass    Underlying class providing the implementation of {@link SSLSocket}.
   * @return            Method to call to indicate the server name of interest to the server.
   */
  private static Method initFrom(Class<?> sslSocketClass) {
        Log.i(TAG, "SSLSocket implementation: " + sslSocketClass.getCanonicalName());
    Method setHostnameMethod = null;
    try {
      setHostnameMethod = sslSocketClass.getMethod(METHOD_NAME, String.class);
    } catch (SecurityException e) {
      Log.e(TAG, "Could not access to SSLSocket#setHostname(String) method ", e);
      
    } catch (NoSuchMethodException e) {
      Log.i(TAG, "Could not find SSLSocket#setHostname(String) method - SNI not supported");
    }
    mSingleInstance.set(new ServerNameIndicator(sslSocketClass, setHostnameMethod));
    return setHostnameMethod;
  }

}

Java Source Code List

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