oc_framework/src/com/owncloud/android/oc_framework/network/ServerNameIndicator.java

   1 /* ownCloud Android client application
   2  *   Copyright (C) 2012-2013 ownCloud Inc.
   3  *
   4  *   This program is free software: you can redistribute it and/or modify
   5  *   it under the terms of the GNU General Public License version 2,
   6  *   as published by the Free Software Foundation.
   7  *
   8  *   This program is distributed in the hope that it will be useful,
   9  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  *   GNU General Public License for more details.
  12  *
  13  *   You should have received a copy of the GNU General Public License
  14  *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  *
  16  */
  17
  18 package com.owncloud.android.oc_framework.network;
  19
  20 import java.lang.ref.WeakReference;
  21 import java.lang.reflect.InvocationTargetException;
  22 import java.lang.reflect.Method;
  23 import java.util.concurrent.atomic.AtomicReference;
  24
  25 import javax.net.ssl.SSLSocket;
  26
  27 import android.util.Log;
  28
  29
  30 /**
  31  * Enables the support of Server Name Indication if existing
  32  * in the underlying network implementation.
  33  *
  34  * Build as a singleton.
  35  *
  36  * @author David A. Velasco
  37  */
  38 public class ServerNameIndicator {
  39
  40         private static final String TAG = ServerNameIndicator.class.getSimpleName();
  41
  42         private static final AtomicReference<ServerNameIndicator> mSingleInstance = new AtomicReference<ServerNameIndicator>();
  43
  44         private static final String METHOD_NAME = "setHostname";
  45
  46         private final WeakReference<Class<?>> mSSLSocketClassRef;
  47         private final WeakReference<Method> mSetHostnameMethodRef;
  48
  49
  50         /**
  51          * Private constructor, class is a singleton.
  52          *
  53          * @param sslSocketClass                Underlying implementation class of {@link SSLSocket} used to connect with the server.
  54          * @param setHostnameMethod             Name of the method to call to enable the SNI support.
  55          */
  56         private ServerNameIndicator(Class<?> sslSocketClass, Method setHostnameMethod) {
  57                 mSSLSocketClassRef = new WeakReference<Class<?>>(sslSocketClass);
  58                 mSetHostnameMethodRef = (setHostnameMethod == null) ? null : new WeakReference<Method>(setHostnameMethod);
  59         }
  60
  61
  62         /**
  63          * Calls the {@code #setHostname(String)} method of the underlying implementation
  64          * of {@link SSLSocket} if exists.
  65          *
  66          * Creates and initializes the single instance of the class when needed
  67          *
  68          * @param hostname              The name of the server host of interest.
  69          * @param sslSocket     Client socket to connect with the server.
  70          */
  71         public static void setServerNameIndication(String hostname, SSLSocket sslSocket) {
  72                 final Method setHostnameMethod = getMethod(sslSocket);
  73                 if (setHostnameMethod != null) {
  74                         try {
  75                                 setHostnameMethod.invoke(sslSocket, hostname);
  76                                 Log.i(TAG, "SNI done, hostname: " + hostname);
  77
  78                         } catch (IllegalArgumentException e) {
  79                                 Log.e(TAG, "Call to SSLSocket#setHost(String) failed ", e);
  80
  81                         } catch (IllegalAccessException e) {
  82                                 Log.e(TAG, "Call to SSLSocket#setHost(String) failed ", e);
  83
  84                         } catch (InvocationTargetException e) {
  85                                 Log.e(TAG, "Call to SSLSocket#setHost(String) failed ", e);
  86                         }
  87                 } else {
  88                         Log.i(TAG, "SNI not supported");
  89                 }
  90         }
  91
  92
  93         /**
  94          * Gets the method to invoke trying to minimize the effective
  95          * application of reflection.
  96          *
  97          * @param       sslSocket               Instance of the SSL socket to use in connection with server.
  98          * @return                                      Method to call to indicate the server name of interest to the server.
  99          */
 100         private static Method getMethod(SSLSocket sslSocket) {
 101                 final Class<?> sslSocketClass = sslSocket.getClass();
 102                 final ServerNameIndicator instance = mSingleInstance.get();
 103                 if (instance == null) {
 104                         return initFrom(sslSocketClass);
 105
 106                 } else if (instance.mSSLSocketClassRef.get() != sslSocketClass) {
 107                         // the underlying class changed
 108                         return initFrom(sslSocketClass);
 109
 110                 } else if (instance.mSetHostnameMethodRef == null) {
 111                         // SNI not supported
 112                         return null;
 113
 114                 } else {
 115                         final Method cachedSetHostnameMethod = instance.mSetHostnameMethodRef.get();
 116                         return (cachedSetHostnameMethod == null) ? initFrom(sslSocketClass) : cachedSetHostnameMethod;
 117                 }
 118         }
 119
 120
 121         /**
 122          * Singleton initializer.
 123          *
 124          * Uses reflection to extract and 'cache' the method to invoke to indicate the desited host name to the server side.
 125          *
 126          * @param       sslSocketClass          Underlying class providing the implementation of {@link SSLSocket}.
 127          * @return                                              Method to call to indicate the server name of interest to the server.
 128          */
 129         private static Method initFrom(Class<?> sslSocketClass) {
 130         Log.i(TAG, "SSLSocket implementation: " + sslSocketClass.getCanonicalName());
 131                 Method setHostnameMethod = null;
 132                 try {
 133                         setHostnameMethod = sslSocketClass.getMethod(METHOD_NAME, String.class);
 134                 } catch (SecurityException e) {
 135                         Log.e(TAG, "Could not access to SSLSocket#setHostname(String) method ", e);
 136
 137                 } catch (NoSuchMethodException e) {
 138                         Log.i(TAG, "Could not find SSLSocket#setHostname(String) method - SNI not supported");
 139                 }
 140                 mSingleInstance.set(new ServerNameIndicator(sslSocketClass, setHostnameMethod));
 141                 return setHostnameMethod;
 142         }
 143
 144 }