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      1 /*
      2  * Copyright (C) 2010 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.server.wifi;
     18 
     19 import android.content.Context;
     20 import android.net.wifi.WifiConfiguration;
     21 import android.net.wifi.WifiConfiguration.KeyMgmt;
     22 import android.os.Environment;
     23 import android.os.Handler;
     24 import android.os.Message;
     25 import android.os.Messenger;
     26 import android.util.Log;
     27 
     28 import com.android.internal.util.AsyncChannel;
     29 import com.android.internal.R;
     30 import com.android.internal.util.State;
     31 import com.android.internal.util.StateMachine;
     32 
     33 import java.io.BufferedInputStream;
     34 import java.io.BufferedOutputStream;
     35 import java.io.DataInputStream;
     36 import java.io.DataOutputStream;
     37 import java.io.FileInputStream;
     38 import java.io.FileOutputStream;
     39 import java.io.IOException;
     40 import java.util.UUID;
     41 
     42 /**
     43  * Provides API to the WifiStateMachine for doing read/write access
     44  * to soft access point configuration
     45  */
     46 class WifiApConfigStore extends StateMachine {
     47 
     48     private Context mContext;
     49     private static final String TAG = "WifiApConfigStore";
     50 
     51     private static final String AP_CONFIG_FILE = Environment.getDataDirectory() +
     52         "/misc/wifi/softap.conf";
     53 
     54     private static final int AP_CONFIG_FILE_VERSION = 1;
     55 
     56     private State mDefaultState = new DefaultState();
     57     private State mInactiveState = new InactiveState();
     58     private State mActiveState = new ActiveState();
     59 
     60     private WifiConfiguration mWifiApConfig = null;
     61     private AsyncChannel mReplyChannel = new AsyncChannel();
     62 
     63     WifiApConfigStore(Context context, Handler target) {
     64         super(TAG, target.getLooper());
     65 
     66         mContext = context;
     67         addState(mDefaultState);
     68             addState(mInactiveState, mDefaultState);
     69             addState(mActiveState, mDefaultState);
     70 
     71         setInitialState(mInactiveState);
     72     }
     73 
     74     public static WifiApConfigStore makeWifiApConfigStore(Context context, Handler target) {
     75         WifiApConfigStore s = new WifiApConfigStore(context, target);
     76         s.start();
     77         return s;
     78     }
     79 
     80     class DefaultState extends State {
     81         public boolean processMessage(Message message) {
     82             switch (message.what) {
     83                 case WifiStateMachine.CMD_SET_AP_CONFIG:
     84                 case WifiStateMachine.CMD_SET_AP_CONFIG_COMPLETED:
     85                     Log.e(TAG, "Unexpected message: " + message);
     86                     break;
     87                 case WifiStateMachine.CMD_REQUEST_AP_CONFIG:
     88                     mReplyChannel.replyToMessage(message,
     89                             WifiStateMachine.CMD_RESPONSE_AP_CONFIG, mWifiApConfig);
     90                     break;
     91                 default:
     92                     Log.e(TAG, "Failed to handle " + message);
     93                     break;
     94             }
     95             return HANDLED;
     96         }
     97     }
     98 
     99     class InactiveState extends State {
    100         public boolean processMessage(Message message) {
    101             switch (message.what) {
    102                 case WifiStateMachine.CMD_SET_AP_CONFIG:
    103                     WifiConfiguration config = (WifiConfiguration) message.obj;
    104                     if (config.SSID != null) {
    105                         mWifiApConfig = (WifiConfiguration) message.obj;
    106                         transitionTo(mActiveState);
    107                     } else {
    108                         Log.e(TAG, "Try to setup AP config without SSID: " + message);
    109                     }
    110                     break;
    111                 default:
    112                     return NOT_HANDLED;
    113             }
    114             return HANDLED;
    115         }
    116     }
    117 
    118     class ActiveState extends State {
    119         public void enter() {
    120             new Thread(new Runnable() {
    121                 public void run() {
    122                     writeApConfiguration(mWifiApConfig);
    123                     sendMessage(WifiStateMachine.CMD_SET_AP_CONFIG_COMPLETED);
    124                 }
    125             }).start();
    126         }
    127 
    128         public boolean processMessage(Message message) {
    129             switch (message.what) {
    130                 //TODO: have feedback to the user when we do this
    131                 //to indicate the write is currently in progress
    132                 case WifiStateMachine.CMD_SET_AP_CONFIG:
    133                     deferMessage(message);
    134                     break;
    135                 case WifiStateMachine.CMD_SET_AP_CONFIG_COMPLETED:
    136                     transitionTo(mInactiveState);
    137                     break;
    138                 default:
    139                     return NOT_HANDLED;
    140             }
    141             return HANDLED;
    142         }
    143     }
    144 
    145     void loadApConfiguration() {
    146         DataInputStream in = null;
    147         try {
    148             WifiConfiguration config = new WifiConfiguration();
    149             in = new DataInputStream(new BufferedInputStream(new FileInputStream(
    150                             AP_CONFIG_FILE)));
    151 
    152             int version = in.readInt();
    153             if (version != 1) {
    154                 Log.e(TAG, "Bad version on hotspot configuration file, set defaults");
    155                 setDefaultApConfiguration();
    156                 return;
    157             }
    158             config.SSID = in.readUTF();
    159             int authType = in.readInt();
    160             config.allowedKeyManagement.set(authType);
    161             if (authType != KeyMgmt.NONE) {
    162                 config.preSharedKey = in.readUTF();
    163             }
    164             mWifiApConfig = config;
    165         } catch (IOException ignore) {
    166             setDefaultApConfiguration();
    167         } finally {
    168             if (in != null) {
    169                 try {
    170                     in.close();
    171                 } catch (IOException e) {}
    172             }
    173         }
    174     }
    175 
    176     Messenger getMessenger() {
    177         return new Messenger(getHandler());
    178     }
    179 
    180     private void writeApConfiguration(final WifiConfiguration config) {
    181         DataOutputStream out = null;
    182         try {
    183             out = new DataOutputStream(new BufferedOutputStream(
    184                         new FileOutputStream(AP_CONFIG_FILE)));
    185 
    186             out.writeInt(AP_CONFIG_FILE_VERSION);
    187             out.writeUTF(config.SSID);
    188             int authType = config.getAuthType();
    189             out.writeInt(authType);
    190             if(authType != KeyMgmt.NONE) {
    191                 out.writeUTF(config.preSharedKey);
    192             }
    193         } catch (IOException e) {
    194             Log.e(TAG, "Error writing hotspot configuration" + e);
    195         } finally {
    196             if (out != null) {
    197                 try {
    198                     out.close();
    199                 } catch (IOException e) {}
    200             }
    201         }
    202     }
    203 
    204     /* Generate a default WPA2 based configuration with a random password.
    205        We are changing the Wifi Ap configuration storage from secure settings to a
    206        flat file accessible only by the system. A WPA2 based default configuration
    207        will keep the device secure after the update */
    208     private void setDefaultApConfiguration() {
    209         WifiConfiguration config = new WifiConfiguration();
    210         config.SSID = mContext.getString(R.string.wifi_tether_configure_ssid_default);
    211         config.allowedKeyManagement.set(KeyMgmt.WPA2_PSK);
    212         String randomUUID = UUID.randomUUID().toString();
    213         //first 12 chars from xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx
    214         config.preSharedKey = randomUUID.substring(0, 8) + randomUUID.substring(9,13);
    215         sendMessage(WifiStateMachine.CMD_SET_AP_CONFIG, config);
    216     }
    217 }
    218