WifiStateMachine: erroneous wifi enabled updates

Update WifiStateMachine to only broadcast wifi availability when in
client mode.  Prior to this fix, wifi would briefly enable/disable when
exiting airplane mode when location scans are enabled and wifi
(client mode) should be disabled.

This CL additionally fixes an issue in WifiController that works around
an assumption in WifiStateMachine that the default mode after supplicant
has started is client mode.  The mode is now set before starting
supplicant so we do not erroneously enter client mode and then
immediately switch to scan only mode.

This CL addresses three known issues where wifi flickers on/off:
1 - wifi disabled, enable wifi location scans
2 - location scans enabled, wifi disabled, enter and exit airplane mode
3 - location scans enabled, wifi disabled, enter airplane mode, enable
and disable wifi, exit airplane mode

Bug: 28336982
Test: frameworks/opt/net/wifi/tests/wifitests/runtests.sh
Test: frameworks/base/wifi/tests/runtests.sh
Test: manually confirmed wifi does not flash on after airplane mode
Change-Id: I9a1d4c7cf00e78c09e3f28e820e058c72c5114b9

2 files changed, 18 insertions, 7 deletions

diff --git a/service/java/com/android/server/wifi/WifiController.java b/service/java/com/android/server/wifi/WifiController.java
index 3e12b3418..6736213ca 100644
--- a/service/java/com/android/server/wifi/WifiController.java
+++ b/service/java/com/android/server/wifi/WifiController.java
@@ -581,8 +581,10 @@ public class WifiController extends StateMachine {
 
         @Override
         public void enter() {
-            mWifiStateMachine.setSupplicantRunning(true);
+            // need to set the mode before starting supplicant because WSM will assume we are going
+            // in to client mode
             mWifiStateMachine.setOperationalMode(WifiStateMachine.SCAN_ONLY_WITH_WIFI_OFF_MODE);
+            mWifiStateMachine.setSupplicantRunning(true);
             // Supplicant can't restart right away, so not the time we switched off
             mDisabledTimestamp = SystemClock.elapsedRealtime();
             mDeferredEnableSerialNumber++;
diff --git a/service/java/com/android/server/wifi/WifiStateMachine.java b/service/java/com/android/server/wifi/WifiStateMachine.java
index 4566d62e1..540fbd827 100644
--- a/service/java/com/android/server/wifi/WifiStateMachine.java
+++ b/service/java/com/android/server/wifi/WifiStateMachine.java
@@ -4068,7 +4068,7 @@ public class WifiStateMachine extends StateMachine implements WifiNative.WifiRss
             switch(message.what) {
                 case WifiMonitor.SUP_CONNECTION_EVENT:
                     if (mVerboseLoggingEnabled) log("Supplicant connection established");
-                    setWifiState(WIFI_STATE_ENABLED);
+
                     mSupplicantRestartCount = 0;
                     /* Reset the supplicant state to indicate the supplicant
                      * state is not known at this time */
@@ -4125,10 +4125,6 @@ public class WifiStateMachine extends StateMachine implements WifiNative.WifiRss
                 logd("SupplicantStartedState enter");
             }
 
-            /* Wifi is available as long as we have a connection to supplicant */
-            mNetworkInfo.setIsAvailable(true);
-            if (mNetworkAgent != null) mNetworkAgent.sendNetworkInfo(mNetworkInfo);
-
             int defaultInterval = mContext.getResources().getInteger(
                     R.integer.config_wifi_supplicant_scan_interval);
 
@@ -4169,7 +4165,7 @@ public class WifiStateMachine extends StateMachine implements WifiNative.WifiRss
              * driver are changed to reduce interference with bluetooth
              */
             mWifiNative.setBluetoothCoexistenceScanMode(mBluetoothConnectionActive);
-            /* initialize network state */
+            // initialize network state
             setNetworkDetailedState(DetailedState.DISCONNECTED);
 
             // Disable legacy multicast filtering, which on some chipsets defaults to enabled.
@@ -4743,6 +4739,16 @@ public class WifiStateMachine extends StateMachine implements WifiNative.WifiRss
 
         @Override
         public void enter() {
+            // Let the system know that wifi is available in client mode.
+            setWifiState(WIFI_STATE_ENABLED);
+
+            mNetworkInfo.setIsAvailable(true);
+            if (mNetworkAgent != null) mNetworkAgent.sendNetworkInfo(mNetworkInfo);
+
+            // initialize network state
+            setNetworkDetailedState(DetailedState.DISCONNECTED);
+
+
             // Inform WifiConnectivityManager that Wifi is enabled
             mWifiConnectivityManager.setWifiEnabled(true);
             // Inform metrics that Wifi is Enabled (but not yet connected)
@@ -4751,6 +4757,9 @@ public class WifiStateMachine extends StateMachine implements WifiNative.WifiRss
 
         @Override
         public void exit() {
+            // Let the system know that wifi is not available since we are exiting client mode.
+            mNetworkInfo.setIsAvailable(false);
+            if (mNetworkAgent != null) mNetworkAgent.sendNetworkInfo(mNetworkInfo);
             // Inform WifiConnectivityManager that Wifi is disabled
             mWifiConnectivityManager.setWifiEnabled(false);
             // Inform metrics that Wifi is being disabled (Toggled, airplane enabled, etc)