wifi: fixup hotspot disconnect on subscriber change

The hotspot should be disconnected only if the IMSI changes (for GSM
devices). SubscriptionInfo#getSubscriptionId() does not return the
IMSI and returns a handle used by the framework. Switch to using the
TelephonyManager#getSubscriberId().

Ticket: CYNGNOS-877, SAMBAR-1151

Change-Id: I7a00600497a9d884dda08a9969cf7f34f9054e2b

1 files changed, 32 insertions, 7 deletions

diff --git a/service/java/com/android/server/wifi/WifiController.java b/service/java/com/android/server/wifi/WifiController.java
index 320db8d..a22f985 100644
--- a/service/java/com/android/server/wifi/WifiController.java
+++ b/service/java/com/android/server/wifi/WifiController.java
@@ -38,6 +38,7 @@ import android.os.WorkSource;
 import android.provider.Settings;
 import android.telephony.SubscriptionInfo;
 import android.telephony.SubscriptionManager;
+import android.telephony.TelephonyManager;
 import android.util.Slog;
 
 import android.widget.Toast;
@@ -633,30 +634,54 @@ class WifiController extends StateMachine {
             mSubListener = new SubscriptionManager.OnSubscriptionsChangedListener() {
                     boolean firstChange = true;
                     SubscriptionInfo lastSub;
+                    String lastSubscriberId;
+
                     @Override
                     public void onSubscriptionsChanged() {
+                        TelephonyManager tm = (TelephonyManager)
+                            mContext.getSystemService(Context.TELEPHONY_SERVICE);
                         final SubscriptionInfo currentSub = SubscriptionManager.from(mContext)
                                 .getDefaultDataSubscriptionInfo();
+
+                        if (currentSub == null) {
+                            // don't disable when we're not sure yet.
+                            return;
+                        }
+
+                        String currentSubscriberId =
+                            tm.getSubscriberId(currentSub.getSubscriptionId());
+
+                        if (currentSubscriberId == null) {
+                            // don't disable when we're not sure yet.
+                            return;
+                        }
+
                         if (firstChange) {
                             lastSub = currentSub;
+                            lastSubscriberId = currentSubscriberId;
                             // we always get a state change on registration.
                             firstChange = false;
                             return;
                         }
-                        if (currentSub == null) {
-                            // don't disable when we're not sure yet.
-                            return;
-                        }
-                        if (lastSub != null && currentSub.getSubscriptionId()
-                                == lastSub.getSubscriptionId()) {
+
+                        // SubscriptionInfo#getSubscriptionId() returns a
+                        // framework handle and is not an IMSI. Don't use it to
+                        // determine if the sub changed.
+                        //
+                        // TelephonyManager#getSubscriberId() returns the IMSI,
+                        // so use that instead
+                        if (currentSubscriberId.equals(lastSubscriberId)) {
                             // don't disable if it's the same subscription
                             return;
                         }
+
                         lastSub = currentSub;
+                        lastSubscriberId = currentSubscriberId;
+
                         Toast.makeText(mContext,
                                 com.android.internal.R.string.subscription_change_disabled_wifi_ap,
                                 Toast.LENGTH_SHORT).show();
-                        log("disabling Wifi AP due to Subscription change");
+                        log("disabling Wifi AP due to Subscriber Id (IMSI) change");
                         WifiController.this.obtainMessage(CMD_SET_AP, 0, 0, null).sendToTarget();
                     }
             };