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      1 /*
      2  * Copyright (C) 2016 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.util;
     18 
     19 import android.content.Context;
     20 import android.net.wifi.WifiConfiguration;
     21 import android.net.wifi.WifiEnterpriseConfig;
     22 import android.telephony.TelephonyManager;
     23 
     24 /**
     25  * Utilities for the Wifi Service to interact with telephony.
     26  */
     27 public class TelephonyUtil {
     28 
     29     /**
     30      * Get the identity for the current SIM or null if the sim is not available
     31      */
     32     public static String getSimIdentity(Context context, int eapMethod) {
     33         TelephonyManager tm = TelephonyManager.from(context);
     34         if (tm != null) {
     35             String imsi = tm.getSubscriberId();
     36             String mccMnc = "";
     37 
     38             if (tm.getSimState() == TelephonyManager.SIM_STATE_READY) {
     39                 mccMnc = tm.getSimOperator();
     40             }
     41 
     42             return buildIdentity(eapMethod, imsi, mccMnc);
     43         } else {
     44             return null;
     45         }
     46     }
     47 
     48     /**
     49      * create Permanent Identity base on IMSI,
     50      *
     51      * rfc4186 & rfc4187:
     52      * identity = usernam@realm
     53      * with username = prefix | IMSI
     54      * and realm is derived MMC/MNC tuple according 3GGP spec(TS23.003)
     55      */
     56     private static String buildIdentity(int eapMethod, String imsi, String mccMnc) {
     57         if (imsi == null || imsi.isEmpty()) {
     58             return null;
     59         }
     60 
     61         String prefix;
     62         if (eapMethod == WifiEnterpriseConfig.Eap.SIM) {
     63             prefix = "1";
     64         } else if (eapMethod == WifiEnterpriseConfig.Eap.AKA) {
     65             prefix = "0";
     66         } else if (eapMethod == WifiEnterpriseConfig.Eap.AKA_PRIME) {
     67             prefix = "6";
     68         } else {  // not a valide EapMethod
     69             return null;
     70         }
     71 
     72         /* extract mcc & mnc from mccMnc */
     73         String mcc;
     74         String mnc;
     75         if (mccMnc != null && !mccMnc.isEmpty()) {
     76             mcc = mccMnc.substring(0, 3);
     77             mnc = mccMnc.substring(3);
     78             if (mnc.length() == 2) {
     79                 mnc = "0" + mnc;
     80             }
     81         } else {
     82             // extract mcc & mnc from IMSI, assume mnc size is 3
     83             mcc = imsi.substring(0, 3);
     84             mnc = imsi.substring(3, 6);
     85         }
     86 
     87         return prefix + imsi + "@wlan.mnc" + mnc + ".mcc" + mcc + ".3gppnetwork.org";
     88     }
     89 
     90     /**
     91      * Checks if the network is a sim config.
     92      *
     93      * @param config Config corresponding to the network.
     94      * @return true if it is a sim config, false otherwise.
     95      */
     96     public static boolean isSimConfig(WifiConfiguration config) {
     97         if (config == null || config.enterpriseConfig == null) {
     98             return false;
     99         }
    100 
    101         return isSimEapMethod(config.enterpriseConfig.getEapMethod());
    102     }
    103 
    104     /**
    105      * Checks if the network is a sim config.
    106      *
    107      * @param method
    108      * @return true if it is a sim config, false otherwise.
    109      */
    110     public static boolean isSimEapMethod(int eapMethod) {
    111         return eapMethod == WifiEnterpriseConfig.Eap.SIM
    112                 || eapMethod == WifiEnterpriseConfig.Eap.AKA
    113                 || eapMethod == WifiEnterpriseConfig.Eap.AKA_PRIME;
    114     }
    115 }
    116