Estimate the probability of getting internet

Use WifiScoreCard statistics to estimate how likely it is that
a candidate BSSID will be able to provide internet access.

Also hook up the success/failure stats for roaming.

Bug: 111230798
Test: atest WifiScoreCardTest WifiCandidatesTest
Change-Id: Ic344ce78c1544fb0f9be46a40e3900067cf5d991

7 files changed, 163 insertions, 17 deletions

diff --git a/service/java/com/android/server/wifi/WifiCandidates.java b/service/java/com/android/server/wifi/WifiCandidates.java
index 24f814023..0513e5c1e 100644
--- a/service/java/com/android/server/wifi/WifiCandidates.java
+++ b/service/java/com/android/server/wifi/WifiCandidates.java
@@ -141,10 +141,14 @@ public class WifiCandidates {
          */
         int getFrequency();
         /**
-         * Gets the predicted throughput in Mbps
+         * Gets the predicted throughput in Mbps.
          */
         int getPredictedThroughputMbps();
         /**
+         * Estimated probability of getting internet access (percent 0-100).
+         */
+        int getEstimatedPercentInternetAvailability();
+        /**
          * Gets statistics from the scorecard.
          */
         @Nullable WifiScoreCardProto.Signal getEventStatistics(WifiScoreCardProto.Event event);
@@ -171,6 +175,7 @@ public class WifiCandidates {
         private final boolean mTrusted;
         private final boolean mCarrierOrPrivileged;
         private final int mPredictedThroughputMbps;
+        private final int mEstimatedPercentInternetAvailability;
 
         CandidateImpl(Key key, WifiConfiguration config,
                 WifiScoreCard.PerBssid perBssid,
@@ -200,6 +205,8 @@ public class WifiCandidates {
             this.mTrusted = config.trusted;
             this.mCarrierOrPrivileged = isCarrierOrPrivileged;
             this.mPredictedThroughputMbps = predictedThroughputMbps;
+            this.mEstimatedPercentInternetAvailability = perBssid == null ? 50 :
+                    perBssid.estimatePercentInternetAvailability();
         }
 
         @Override
@@ -287,6 +294,11 @@ public class WifiCandidates {
             return mPredictedThroughputMbps;
         }
 
+        @Override
+        public int getEstimatedPercentInternetAvailability() {
+            return mEstimatedPercentInternetAvailability;
+        }
+
         /**
          * Accesses statistical information from the score card
          */
@@ -309,12 +321,13 @@ public class WifiCandidates {
                         + ", ";
             }
             return "Candidate { "
-                    + "networkId = " + getNetworkConfigId() + ", "
+                    + "config = " + getNetworkConfigId() + ", "
                     + "bssid = " + key.bssid + ", "
-                    + "frequency = " + getFrequency() + ", "
+                    + "freq = " + getFrequency() + ", "
                     + "rssi = " + getScanRssi() + ", "
                     + "Mbps = " + getPredictedThroughputMbps() + ", "
                     + "nominator = " + getNominatorId() + ", "
+                    + "pInternet = " + getEstimatedPercentInternetAvailability() + ", "
                     + lastSelectionWeightString
                     + (isCurrentBssid() ? "connected, " : "")
                     + (isCurrentNetwork() ? "current, " : "")
diff --git a/service/java/com/android/server/wifi/WifiNetworkScoreCache.java b/service/java/com/android/server/wifi/WifiNetworkScoreCache.java
index 6bb3708ac..6bb3708ac 100755..100644
--- a/service/java/com/android/server/wifi/WifiNetworkScoreCache.java
+++ b/service/java/com/android/server/wifi/WifiNetworkScoreCache.java
diff --git a/service/java/com/android/server/wifi/WifiScoreCard.java b/service/java/com/android/server/wifi/WifiScoreCard.java
index fdf7a678b..071b9634d 100644
--- a/service/java/com/android/server/wifi/WifiScoreCard.java
+++ b/service/java/com/android/server/wifi/WifiScoreCard.java
@@ -205,7 +205,7 @@ public class WifiScoreCard {
      *
      * We want to gather statistics only on the first success.
      */
-    private boolean mValidated = false;
+    private boolean mValidatedThisConnectionAtLeastOnce = false;
 
     /**
      * A note to ourself that we are attempting a network switch
@@ -279,7 +279,7 @@ public class WifiScoreCard {
         }
         mTsRoam = TS_NONE;
         mPolled = false;
-        mValidated = false;
+        mValidatedThisConnectionAtLeastOnce = false;
         mNonlocalDisconnection = false;
     }
 
@@ -363,9 +363,9 @@ public class WifiScoreCard {
      * @param wifiInfo object holding relevant values
      */
     public void noteValidationSuccess(@NonNull ExtendedWifiInfo wifiInfo) {
-        if (mValidated) return; // Only once per connection
+        if (mValidatedThisConnectionAtLeastOnce) return; // Only once per connection
         updatePerBssid(Event.VALIDATION_SUCCESS, wifiInfo);
-        mValidated = true;
+        mValidatedThisConnectionAtLeastOnce = true;
         doWrites();
     }
 
@@ -375,7 +375,7 @@ public class WifiScoreCard {
      * @param wifiInfo object holding relevant values
      */
     public void noteValidationFailure(@NonNull ExtendedWifiInfo wifiInfo) {
-        mValidated = false;
+        // VALIDATION_FAILURE is not currently recorded.
     }
 
     /**
@@ -448,10 +448,11 @@ public class WifiScoreCard {
      * @param wifiInfo object holding relevant values
      */
     public void noteIpReachabilityLost(@NonNull ExtendedWifiInfo wifiInfo) {
-        updatePerBssid(Event.IP_REACHABILITY_LOST, wifiInfo);
         if (mTsRoam > TS_NONE) {
             mTsConnectionAttemptStart = mTsRoam; // just to update elapsed
             updatePerBssid(Event.ROAM_FAILURE, wifiInfo);
+        } else {
+            updatePerBssid(Event.IP_REACHABILITY_LOST, wifiInfo);
         }
         // No need to call resetConnectionStateInternal() because
         // resetConnectionState() will be called after WifiNative.disconnect() in ClientModeImpl
@@ -466,7 +467,7 @@ public class WifiScoreCard {
      *
      * @param wifiInfo object holding relevant values
      */
-    public void noteRoam(@NonNull ExtendedWifiInfo wifiInfo) {
+    private void noteRoam(@NonNull ExtendedWifiInfo wifiInfo) {
         updatePerBssid(Event.LAST_POLL_BEFORE_ROAM, wifiInfo);
         mTsRoam = mClock.getElapsedSinceBootMillis();
     }
@@ -479,6 +480,10 @@ public class WifiScoreCard {
      */
     public void noteSupplicantStateChanging(@NonNull ExtendedWifiInfo wifiInfo,
             SupplicantState state) {
+        if (state == SupplicantState.COMPLETED && wifiInfo.getSupplicantState() == state) {
+            // Our signal that a firmware roam has occurred
+            noteRoam(wifiInfo);
+        }
         logd("Changing state to " + state + " " + wifiInfo);
     }
 
@@ -788,6 +793,38 @@ public class WifiScoreCard {
             }
             merge(ap);
         }
+
+        /**
+         * Estimates the probability of getting internet access, based on the
+         * device experience.
+         *
+         * @return a probability, expressed as a percentage in the range 0 to 100
+         */
+        public int estimatePercentInternetAvailability() {
+            // Initialize counts accoring to Laplace's rule of succession
+            int trials = 2;
+            int successes = 1;
+            // Aggregate over all of the frequencies
+            for (PerSignal s : mSignalForEventAndFrequency.values()) {
+                switch (s.event) {
+                    case IP_CONFIGURATION_SUCCESS:
+                        if (s.elapsedMs != null) {
+                            trials += s.elapsedMs.count;
+                        }
+                        break;
+                    case VALIDATION_SUCCESS:
+                        if (s.elapsedMs != null) {
+                            successes += s.elapsedMs.count;
+                        }
+                        break;
+                    default:
+                        break;
+                }
+            }
+            // Note that because of roaming it is possible to count successes
+            // without corresponding trials.
+            return Math.min(Math.max(Math.round(successes * 100.0f / trials), 0), 100);
+        }
     }
 
     /**
@@ -1712,7 +1749,7 @@ public class WifiScoreCard {
             Preconditions.checkArgument(frequency == signal.getFrequency());
             rssi.merge(signal.getRssi());
             linkspeed.merge(signal.getLinkspeed());
-            if (signal.hasElapsedMs()) {
+            if (elapsedMs != null && signal.hasElapsedMs()) {
                 elapsedMs.merge(signal.getElapsedMs());
             }
             return this;
diff --git a/tests/wifitests/Android.bp b/tests/wifitests/Android.bp
index 6ba8c908a..851a6016e 100644
--- a/tests/wifitests/Android.bp
+++ b/tests/wifitests/Android.bp
@@ -402,6 +402,9 @@ android_test {
             "com.android.server.wifi.WifiCandidates",
             "com.android.server.wifi.WifiCandidates$*",
             "com.android.server.wifi.WifiCandidates.**",
+            "com.android.server.wifi.WifiCarrierInfoManager",
+            "com.android.server.wifi.WifiCarrierInfoManager$*",
+            "com.android.server.wifi.WifiCarrierInfoManager.**",
             "com.android.server.wifi.WifiChannelUtilization",
             "com.android.server.wifi.WifiChannelUtilization$*",
             "com.android.server.wifi.WifiChannelUtilization.**",
@@ -933,9 +936,6 @@ android_test {
             "com.android.server.wifi.util.StringUtil",
             "com.android.server.wifi.util.StringUtil$*",
             "com.android.server.wifi.util.StringUtil.**",
-            "com.android.server.wifi.WifiCarrierInfoManager",
-            "com.android.server.wifi.WifiCarrierInfoManager$*",
-            "com.android.server.wifi.WifiCarrierInfoManager.**",
             "com.android.server.wifi.util.TimedQuotaManager",
             "com.android.server.wifi.util.TimedQuotaManager$*",
             "com.android.server.wifi.util.TimedQuotaManager.**",
diff --git a/tests/wifitests/src/com/android/server/wifi/ConcreteCandidate.java b/tests/wifitests/src/com/android/server/wifi/ConcreteCandidate.java
index b95a1171b..37d2945cf 100644
--- a/tests/wifitests/src/com/android/server/wifi/ConcreteCandidate.java
+++ b/tests/wifitests/src/com/android/server/wifi/ConcreteCandidate.java
@@ -40,6 +40,7 @@ public final class ConcreteCandidate implements WifiCandidates.Candidate {
     private int mScanRssi = -127;
     private int mFrequency = -1;
     private int mPredictedThroughputMbps = 0;
+    private int mEstimatedPercentInternetAvailability = 50;
 
     private final Map<WifiScoreCardProto.Event, WifiScoreCardProto.Signal>
             mEventStatisticsMap = new ArrayMap<>();
@@ -65,6 +66,8 @@ public final class ConcreteCandidate implements WifiCandidates.Candidate {
         mScanRssi = candidate.getScanRssi();
         mFrequency = candidate.getFrequency();
         mPredictedThroughputMbps = candidate.getPredictedThroughputMbps();
+        mEstimatedPercentInternetAvailability = candidate
+                .getEstimatedPercentInternetAvailability();
         for (WifiScoreCardProto.Event event : WifiScoreCardProto.Event.values()) {
             WifiScoreCardProto.Signal signal = candidate.getEventStatistics(event);
             if (signal != null) {
@@ -243,6 +246,16 @@ public final class ConcreteCandidate implements WifiCandidates.Candidate {
         return mPredictedThroughputMbps;
     }
 
+    public ConcreteCandidate setEstimatedPercentInternetAvailability(int percent) {
+        mEstimatedPercentInternetAvailability = percent;
+        return this;
+    }
+
+    @Override
+    public int getEstimatedPercentInternetAvailability() {
+        return mEstimatedPercentInternetAvailability;
+    }
+
     public ConcreteCandidate setEventStatistics(
             WifiScoreCardProto.Event event,
             WifiScoreCardProto.Signal signal) {
diff --git a/tests/wifitests/src/com/android/server/wifi/WifiCandidatesTest.java b/tests/wifitests/src/com/android/server/wifi/WifiCandidatesTest.java
index 7ce59c9ee..9ff064ed1 100644
--- a/tests/wifitests/src/com/android/server/wifi/WifiCandidatesTest.java
+++ b/tests/wifitests/src/com/android/server/wifi/WifiCandidatesTest.java
@@ -79,6 +79,7 @@ public class WifiCandidatesTest extends WifiBaseTest {
         doReturn(mScanResult1).when(mScanDetail1).getScanResult();
         doReturn(mScanResult2).when(mScanDetail2).getScanResult();
         doReturn(mPerBssid).when(mWifiScoreCard).lookupBssid(any(), any());
+        doReturn(50).when(mPerBssid).estimatePercentInternetAvailability();
         MockResources mResources = new MockResources();
         mResources.setBoolean(R.bool.config_wifiSaeUpgradeEnabled, true);
         doReturn(mResources).when(mContext).getResources();
@@ -182,13 +183,15 @@ public class WifiCandidatesTest extends WifiBaseTest {
      */
     @Test
     public void testCandidateToString() throws Exception {
+        doReturn(57).when(mPerBssid).estimatePercentInternetAvailability();
         mWifiCandidates.add(mScanDetail1, mConfig1, 2, 0.0015001, false, 100);
         WifiCandidates.Candidate c = mWifiCandidates.getGroupedCandidates()
                 .iterator().next().iterator().next();
         String s = c.toString();
         assertTrue(s, s.contains(" nominator = 2, "));
-        assertTrue(s, s.contains(" networkId = " + mConfig1.networkId + ", "));
+        assertTrue(s, s.contains(" config = " + mConfig1.networkId + ", "));
         assertTrue(s, s.contains(" lastSelectionWeight = 0.002, ")); // should be rounded
+        assertTrue(s, s.contains(" pInternet = 57, "));
         for (String x : s.split(",")) {
             if (x.startsWith("Candidate {")) x = x.substring("Candidate {".length());
             if (x.endsWith(" }")) x = x.substring(0, x.length() - 2);
diff --git a/tests/wifitests/src/com/android/server/wifi/WifiScoreCardTest.java b/tests/wifitests/src/com/android/server/wifi/WifiScoreCardTest.java
index 3fc62609a..e5525c4c7 100644
--- a/tests/wifitests/src/com/android/server/wifi/WifiScoreCardTest.java
+++ b/tests/wifitests/src/com/android/server/wifi/WifiScoreCardTest.java
@@ -39,6 +39,7 @@ import static org.mockito.Mockito.*;
 
 import android.content.Context;
 import android.net.MacAddress;
+import android.net.wifi.SupplicantState;
 import android.net.wifi.WifiInfo;
 import android.net.wifi.WifiSsid;
 import android.util.Base64;
@@ -72,6 +73,7 @@ import java.util.List;
  */
 @SmallTest
 public class WifiScoreCardTest extends WifiBaseTest {
+
     static final WifiSsid TEST_SSID_1 = WifiSsid.createFromAsciiEncoded("Joe's Place");
     static final WifiSsid TEST_SSID_2 = WifiSsid.createFromAsciiEncoded("Poe's Ravn");
 
@@ -364,9 +366,10 @@ public class WifiScoreCardTest extends WifiBaseTest {
         secondsPass(9900);
         // Second validation success should not matter.
         mWifiScoreCard.noteValidationSuccess(mWifiInfo);
+        mWifiInfo.setRssi(-88);
+        mWifiScoreCard.noteIpReachabilityLost(mWifiInfo);
         mWifiScoreCard.noteWifiDisabled(mWifiInfo);
 
-
         // Now verify
         WifiScoreCard.PerBssid perBssid = mWifiScoreCard.fetchByBssid(TEST_BSSID_1);
         assertEquals(1, perBssid.lookupSignal(Event.IP_CONFIGURATION_SUCCESS, 5805)
@@ -375,14 +378,91 @@ public class WifiScoreCardTest extends WifiBaseTest {
                 .elapsedMs.sum, TOL);
         assertEquals(9999999.0, perBssid.lookupSignal(Event.WIFI_DISABLED, 5805)
                 .elapsedMs.maxValue, TOL);
-        assertEquals(999.0,  perBssid.lookupSignal(Event.FIRST_POLL_AFTER_CONNECTION, 5805)
+        assertEquals(999.0, perBssid.lookupSignal(Event.FIRST_POLL_AFTER_CONNECTION, 5805)
                 .elapsedMs.minValue, TOL);
         assertEquals(99999.0, perBssid.lookupSignal(Event.VALIDATION_SUCCESS, 5805)
                 .elapsedMs.sum, TOL);
+        assertEquals(-88.0, perBssid.lookupSignal(Event.IP_REACHABILITY_LOST, 5805)
+                .rssi.sum, TOL);
         assertNull(perBssid.lookupSignal(Event.SIGNAL_POLL, 5805).elapsedMs);
     }
 
     /**
+     * Firmware roam
+     */
+    @Test
+    public void testFirmwareRoam() throws Exception {
+        // Start out disconnected; start connecting
+        mWifiInfo.setBSSID(android.net.wifi.WifiInfo.DEFAULT_MAC_ADDRESS);
+        mWifiScoreCard.noteConnectionAttempt(mWifiInfo, -53, mWifiInfo.getSSID());
+
+        // First poll has a bad RSSI
+        millisecondsPass(111);
+        mWifiInfo.setBSSID(TEST_BSSID_1.toString());
+        mWifiInfo.setSupplicantState(SupplicantState.COMPLETED);
+        mWifiInfo.setFrequency(5805);
+        mWifiInfo.setRssi(WifiInfo.INVALID_RSSI);
+
+        // A bit later, connection is complete (up through DHCP)
+        millisecondsPass(222);
+        mWifiInfo.setRssi(-55);
+        mWifiScoreCard.noteIpConfiguration(mWifiInfo);
+
+        millisecondsPass(666);
+        mWifiInfo.setRssi(-77);
+        // Rssi polls for 99 seconds
+        for (int i = 0; i < 99; i += 9) {
+            mWifiScoreCard.noteSignalPoll(mWifiInfo);
+            secondsPass(9);
+        }
+
+        // Make sure our simulated time adds up
+        assertEquals(mMilliSecondsSinceBoot, 99999);
+        // Validation success, rather late!
+        mWifiScoreCard.noteValidationSuccess(mWifiInfo);
+        // Simulate a successful roam
+        mWifiScoreCard.noteSupplicantStateChanging(mWifiInfo, SupplicantState.COMPLETED);
+        millisecondsPass(1);
+        mWifiInfo.setBSSID(TEST_BSSID_2.toString());
+        mWifiInfo.setRssi(-66);
+        mWifiInfo.setFrequency(2412);
+        mWifiInfo.setSupplicantState(SupplicantState.COMPLETED);
+        mWifiScoreCard.noteSupplicantStateChanged(mWifiInfo);
+        secondsPass(9);
+        assertEquals(mMilliSecondsSinceBoot, 109000);
+        mWifiScoreCard.noteSignalPoll(mWifiInfo);
+
+        // Simulate an unsuccessful roam
+        secondsPass(1);
+        mWifiInfo.setRssi(-74);
+        mWifiScoreCard.noteSignalPoll(mWifiInfo);
+        secondsPass(1);
+        mWifiScoreCard.noteSupplicantStateChanging(mWifiInfo, SupplicantState.COMPLETED);
+        mWifiInfo.setBSSID(TEST_BSSID_1.toString());
+        mWifiInfo.setFrequency(5805);
+        mWifiInfo.setSupplicantState(SupplicantState.COMPLETED);
+        mWifiScoreCard.noteSupplicantStateChanged(mWifiInfo);
+        secondsPass(3);
+        mWifiScoreCard.noteIpReachabilityLost(mWifiInfo);
+
+        // Now verify
+        WifiScoreCard.PerBssid perBssid = mWifiScoreCard.fetchByBssid(TEST_BSSID_1);
+        assertEquals(1, perBssid.lookupSignal(Event.IP_CONFIGURATION_SUCCESS, 5805)
+                .elapsedMs.count);
+        assertEquals(-77, perBssid.lookupSignal(Event.LAST_POLL_BEFORE_ROAM, 5805)
+                .rssi.minValue, TOL);
+        assertEquals(1, perBssid.lookupSignal(Event.ROAM_FAILURE, 5805)
+                .rssi.count);
+
+        assertEquals(67, perBssid.estimatePercentInternetAvailability());
+
+        perBssid = mWifiScoreCard.fetchByBssid(TEST_BSSID_2);
+        assertEquals(-66.0, perBssid.lookupSignal(Event.ROAM_SUCCESS, 2412)
+                .rssi.sum, TOL);
+        assertEquals(50, perBssid.estimatePercentInternetAvailability());
+    }
+
+    /**
      * Constructs a protobuf form of AccessPoint example.
      */
     private byte[] makeSerializedAccessPointExample() {