From 80d0986ea4ec6d2bff2af02a9e1a31593c200540 Mon Sep 17 00:00:00 2001
From: xshu <xshu@google.com>
Date: Thu, 10 Sep 2020 19:46:04 -0700
Subject: Exponential backoff for external score blocklist

(cherry-picked from 89ab95af87eff69a5865124fc4bc529e1f6efb52)
Changes:
1. When the external scorer marks a network as unacceptable, block the
BSSID for 0.5/1/2/... up to 64 minutes instead of the previous fixed 30 seconds.
2. Modified test cases to increase coverage.

Bug: 158695052
Test: atest com.android.server.wifi

Change-Id: I0f1413563530c8e66ea6a061c78bc49bffd61091
---
 .../android/server/wifi/BssidBlocklistMonitor.java |  16 +++-
 .../com/android/server/wifi/WifiScoreReport.java   |   4 +-
 service/res/values/config.xml                      |   7 ++
 service/res/values/overlayable.xml                 |   1 +
 .../server/wifi/BssidBlocklistMonitorTest.java     | 104 ++++++++++++++-------
 .../android/server/wifi/WifiScoreReportTest.java   |  15 ++-
 6 files changed, 102 insertions(+), 45 deletions(-)

diff --git a/service/java/com/android/server/wifi/BssidBlocklistMonitor.java b/service/java/com/android/server/wifi/BssidBlocklistMonitor.java
index d96fdb39e..e3fe32ab7 100644
--- a/service/java/com/android/server/wifi/BssidBlocklistMonitor.java
+++ b/service/java/com/android/server/wifi/BssidBlocklistMonitor.java
@@ -330,8 +330,7 @@ public class BssidBlocklistMonitor {
             if (shouldWaitForWatchdogToTriggerFirst(bssid, reasonCode)) {
                 return false;
             }
-            int baseBlockDurationMs = mContext.getResources().getInteger(
-                    R.integer.config_wifiBssidBlocklistMonitorBaseBlockDurationMs);
+            int baseBlockDurationMs = getBaseBlockDurationForReason(reasonCode);
             addToBlocklist(entry,
                     getBlocklistDurationWithExponentialBackoff(currentStreak, baseBlockDurationMs),
                     reasonCode, rssi);
@@ -341,6 +340,17 @@ public class BssidBlocklistMonitor {
         return false;
     }
 
+    private int getBaseBlockDurationForReason(int blockReason) {
+        switch (blockReason) {
+            case REASON_FRAMEWORK_DISCONNECT_CONNECTED_SCORE:
+                return mContext.getResources().getInteger(R.integer
+                        .config_wifiBssidBlocklistMonitorConnectedScoreBaseBlockDurationMs);
+            default:
+                return mContext.getResources().getInteger(
+                        R.integer.config_wifiBssidBlocklistMonitorBaseBlockDurationMs);
+        }
+    }
+
     /**
      * Note a failure event on a bssid and perform appropriate actions.
      * @return True if the blocklist has been modified.
@@ -383,6 +393,8 @@ public class BssidBlocklistMonitor {
                 ssid, bssid, connectionTime);
         if (connectionTime - prevConnectionTime > ABNORMAL_DISCONNECT_RESET_TIME_MS) {
             mWifiScoreCard.resetBssidBlocklistStreak(ssid, bssid, REASON_ABNORMAL_DISCONNECT);
+            mWifiScoreCard.resetBssidBlocklistStreak(ssid, bssid,
+                    REASON_FRAMEWORK_DISCONNECT_CONNECTED_SCORE);
         }
 
         BssidStatus status = mBssidStatusMap.get(bssid);
diff --git a/service/java/com/android/server/wifi/WifiScoreReport.java b/service/java/com/android/server/wifi/WifiScoreReport.java
index 80a561d05..bd92c6dac 100644
--- a/service/java/com/android/server/wifi/WifiScoreReport.java
+++ b/service/java/com/android/server/wifi/WifiScoreReport.java
@@ -60,7 +60,6 @@ public class WifiScoreReport {
     private static final int WIFI_CONNECTED_NETWORK_SCORER_IDENTIFIER = 0;
     private static final int INVALID_SESSION_ID = -1;
     private static final long MIN_TIME_TO_WAIT_BEFORE_BLOCKLIST_BSSID_MILLIS = 29000;
-    private static final long DURATION_TO_BLOCKLIST_BSSID_AFTER_FIRST_EXITING_MILLIS = 30000;
     private static final long INVALID_WALL_CLOCK_MILLIS = -1;
 
     /**
@@ -751,9 +750,8 @@ public class WifiScoreReport {
         if ((mLastScoreBreachLowTimeMillis != INVALID_WALL_CLOCK_MILLIS)
                 && ((millis - mLastScoreBreachLowTimeMillis)
                         >= MIN_TIME_TO_WAIT_BEFORE_BLOCKLIST_BSSID_MILLIS)) {
-            mBssidBlocklistMonitor.blockBssidForDurationMs(mWifiInfo.getBSSID(),
+            mBssidBlocklistMonitor.handleBssidConnectionFailure(mWifiInfo.getBSSID(),
                     mWifiInfo.getSSID(),
-                    DURATION_TO_BLOCKLIST_BSSID_AFTER_FIRST_EXITING_MILLIS,
                     BssidBlocklistMonitor.REASON_FRAMEWORK_DISCONNECT_CONNECTED_SCORE,
                     mWifiInfo.getRssi());
             mLastScoreBreachLowTimeMillis = INVALID_WALL_CLOCK_MILLIS;
diff --git a/service/res/values/config.xml b/service/res/values/config.xml
index 1220c260a..0264c3eae 100644
--- a/service/res/values/config.xml
+++ b/service/res/values/config.xml
@@ -355,6 +355,13 @@
     config_wifiBssidBlocklistMonitorFailureStreakCap is set to 7-->
     <integer translatable="false" name="config_wifiBssidBlocklistMonitorBaseBlockDurationMs"> 300000 </integer>
 
+    <!-- Base duration to block a BSSID after the external connected scorer sets wifi as unusable.
+    The block duration is increased exponentially if the same BSSID is repeated marked as unusable.
+    ie. 0.5/1/2/4/8/16/32/64 minutes - capped at 64 minutes because the default for
+    config_wifiBssidBlocklistMonitorFailureStreakCap is set to 7. The block duration is reset to
+    the base value 3 hours after the latest connection to this BSSID. -->
+    <integer translatable="false" name="config_wifiBssidBlocklistMonitorConnectedScoreBaseBlockDurationMs"> 30000 </integer>
+
     <!-- The failure streak is the number of times a BSSID consecutively gets blocked without ever
     successfully connecting in between, and is used to calculate the exponentially growing blocklist time.
     The config_wifiBssidBlocklistMonitorFailureStreakCap controls how many times the block duration
diff --git a/service/res/values/overlayable.xml b/service/res/values/overlayable.xml
index 56c94246d..60764ba6e 100644
--- a/service/res/values/overlayable.xml
+++ b/service/res/values/overlayable.xml
@@ -114,6 +114,7 @@
           <item type="integer" name="config_wifiBssidBlocklistMonitorDhcpFailureThreshold" />
           <item type="integer" name="config_wifiBssidBlocklistMonitorAbnormalDisconnectThreshold" />
           <item type="integer" name="config_wifiBssidBlocklistMonitorBaseBlockDurationMs" />
+          <item type="integer" name="config_wifiBssidBlocklistMonitorConnectedScoreBaseBlockDurationMs" />
           <item type="integer" name="config_wifiBssidBlocklistMonitorFailureStreakCap" />
           <item type="integer" name="config_wifiBssidBlocklistAbnormalDisconnectTimeWindowMs" />
           <item type="bool" name="config_wifiScanHiddenNetworksScanOnlyMode" />
diff --git a/tests/wifitests/src/com/android/server/wifi/BssidBlocklistMonitorTest.java b/tests/wifitests/src/com/android/server/wifi/BssidBlocklistMonitorTest.java
index d6333b363..1007391e3 100644
--- a/tests/wifitests/src/com/android/server/wifi/BssidBlocklistMonitorTest.java
+++ b/tests/wifitests/src/com/android/server/wifi/BssidBlocklistMonitorTest.java
@@ -18,6 +18,7 @@ package com.android.server.wifi;
 
 import static org.junit.Assert.*;
 import static org.mockito.Mockito.*;
+import static org.mockito.Mockito.times;
 
 import android.content.Context;
 import android.net.wifi.ScanResult;
@@ -34,6 +35,7 @@ import org.mockito.MockitoAnnotations;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 
@@ -57,23 +59,28 @@ public class BssidBlocklistMonitorTest {
     private static final int TEST_L2_FAILURE = BssidBlocklistMonitor.REASON_ASSOCIATION_REJECTION;
     private static final int TEST_DHCP_FAILURE = BssidBlocklistMonitor.REASON_DHCP_FAILURE;
     private static final long BASE_BLOCKLIST_DURATION = TimeUnit.MINUTES.toMillis(5); // 5 minutes
+    private static final long BASE_CONNECTED_SCORE_BLOCKLIST_DURATION =
+            TimeUnit.SECONDS.toMillis(30);
     private static final long ABNORMAL_DISCONNECT_TIME_WINDOW_MS = TimeUnit.SECONDS.toMillis(30);
     private static final long ABNORMAL_DISCONNECT_RESET_TIME_MS = TimeUnit.HOURS.toMillis(3);
     private static final int FAILURE_STREAK_CAP = 7;
-    private static final int[] FAILURE_COUNT_DISABLE_THRESHOLD = {
-            1,  //  threshold for REASON_AP_UNABLE_TO_HANDLE_NEW_STA
-            1,  //  threshold for REASON_NETWORK_VALIDATION_FAILURE
-            1,  //  threshold for REASON_WRONG_PASSWORD
-            1,  //  threshold for REASON_EAP_FAILURE
-            3,  //  threshold for REASON_ASSOCIATION_REJECTION
-            3,  //  threshold for REASON_ASSOCIATION_TIMEOUT
-            3,  //  threshold for REASON_AUTHENTICATION_FAILURE
-            3,  //  threshold for REASON_DHCP_FAILURE
-            3   //  threshold for REASON_ABNORMAL_DISCONNECT
-    };
+    private static final Map<Integer, Integer> BLOCK_REASON_TO_DISABLE_THRESHOLD_MAP =
+            Map.ofEntries(
+                    Map.entry(BssidBlocklistMonitor.REASON_AP_UNABLE_TO_HANDLE_NEW_STA, 1),
+                    Map.entry(BssidBlocklistMonitor.REASON_NETWORK_VALIDATION_FAILURE, 1),
+                    Map.entry(BssidBlocklistMonitor.REASON_WRONG_PASSWORD, 1),
+                    Map.entry(BssidBlocklistMonitor.REASON_EAP_FAILURE, 1),
+                    Map.entry(BssidBlocklistMonitor.REASON_ASSOCIATION_REJECTION, 3),
+                    Map.entry(BssidBlocklistMonitor.REASON_ASSOCIATION_TIMEOUT, 3),
+                    Map.entry(BssidBlocklistMonitor.REASON_AUTHENTICATION_FAILURE, 3),
+                    Map.entry(BssidBlocklistMonitor.REASON_DHCP_FAILURE, 3),
+                    Map.entry(BssidBlocklistMonitor.REASON_ABNORMAL_DISCONNECT, 3),
+                    Map.entry(BssidBlocklistMonitor.REASON_FRAMEWORK_DISCONNECT_MBO_OCE, 1),
+                    Map.entry(BssidBlocklistMonitor.REASON_FRAMEWORK_DISCONNECT_FAST_RECONNECT, 1),
+                    Map.entry(BssidBlocklistMonitor.REASON_FRAMEWORK_DISCONNECT_CONNECTED_SCORE, 1)
+            );
     private static final int NUM_FAILURES_TO_BLOCKLIST =
-            FAILURE_COUNT_DISABLE_THRESHOLD[TEST_L2_FAILURE];
-
+            BLOCK_REASON_TO_DISABLE_THRESHOLD_MAP.get(TEST_L2_FAILURE);
 
     @Mock private Context mContext;
     @Mock private WifiConnectivityHelper mWifiConnectivityHelper;
@@ -97,34 +104,46 @@ public class BssidBlocklistMonitorTest {
         mResources = new MockResources();
         mResources.setInteger(R.integer.config_wifiBssidBlocklistMonitorBaseBlockDurationMs,
                 (int) BASE_BLOCKLIST_DURATION);
+        mResources.setInteger(
+                R.integer.config_wifiBssidBlocklistMonitorConnectedScoreBaseBlockDurationMs,
+                (int) BASE_CONNECTED_SCORE_BLOCKLIST_DURATION);
         mResources.setInteger(R.integer.config_wifiBssidBlocklistMonitorFailureStreakCap,
                 FAILURE_STREAK_CAP);
         mResources.setInteger(R.integer.config_wifiBssidBlocklistAbnormalDisconnectTimeWindowMs,
                 (int) ABNORMAL_DISCONNECT_TIME_WINDOW_MS);
         mResources.setInteger(
                 R.integer.config_wifiBssidBlocklistMonitorApUnableToHandleNewStaThreshold,
-                FAILURE_COUNT_DISABLE_THRESHOLD[0]);
+                BLOCK_REASON_TO_DISABLE_THRESHOLD_MAP.get(
+                        BssidBlocklistMonitor.REASON_AP_UNABLE_TO_HANDLE_NEW_STA));
         mResources.setInteger(
                 R.integer.config_wifiBssidBlocklistMonitorNetworkValidationFailureThreshold,
-                FAILURE_COUNT_DISABLE_THRESHOLD[1]);
+                BLOCK_REASON_TO_DISABLE_THRESHOLD_MAP.get(
+                        BssidBlocklistMonitor.REASON_NETWORK_VALIDATION_FAILURE));
         mResources.setInteger(R.integer.config_wifiBssidBlocklistMonitorWrongPasswordThreshold,
-                FAILURE_COUNT_DISABLE_THRESHOLD[2]);
+                BLOCK_REASON_TO_DISABLE_THRESHOLD_MAP.get(
+                        BssidBlocklistMonitor.REASON_WRONG_PASSWORD));
         mResources.setInteger(R.integer.config_wifiBssidBlocklistMonitorEapFailureThreshold,
-                FAILURE_COUNT_DISABLE_THRESHOLD[3]);
+                BLOCK_REASON_TO_DISABLE_THRESHOLD_MAP.get(
+                        BssidBlocklistMonitor.REASON_EAP_FAILURE));
         mResources.setInteger(
                 R.integer.config_wifiBssidBlocklistMonitorAssociationRejectionThreshold,
-                FAILURE_COUNT_DISABLE_THRESHOLD[4]);
+                BLOCK_REASON_TO_DISABLE_THRESHOLD_MAP.get(
+                        BssidBlocklistMonitor.REASON_ASSOCIATION_REJECTION));
         mResources.setInteger(
                 R.integer.config_wifiBssidBlocklistMonitorAssociationTimeoutThreshold,
-                FAILURE_COUNT_DISABLE_THRESHOLD[5]);
+                BLOCK_REASON_TO_DISABLE_THRESHOLD_MAP.get(
+                        BssidBlocklistMonitor.REASON_ASSOCIATION_TIMEOUT));
         mResources.setInteger(
                 R.integer.config_wifiBssidBlocklistMonitorAuthenticationFailureThreshold,
-                FAILURE_COUNT_DISABLE_THRESHOLD[6]);
+                BLOCK_REASON_TO_DISABLE_THRESHOLD_MAP.get(
+                        BssidBlocklistMonitor.REASON_AUTHENTICATION_FAILURE));
         mResources.setInteger(R.integer.config_wifiBssidBlocklistMonitorDhcpFailureThreshold,
-                FAILURE_COUNT_DISABLE_THRESHOLD[7]);
+                BLOCK_REASON_TO_DISABLE_THRESHOLD_MAP.get(
+                        BssidBlocklistMonitor.REASON_DHCP_FAILURE));
         mResources.setInteger(
                 R.integer.config_wifiBssidBlocklistMonitorAbnormalDisconnectThreshold,
-                FAILURE_COUNT_DISABLE_THRESHOLD[8]);
+                BLOCK_REASON_TO_DISABLE_THRESHOLD_MAP.get(
+                        BssidBlocklistMonitor.REASON_ABNORMAL_DISCONNECT));
 
         when(mContext.getResources()).thenReturn(mResources);
         mBssidBlocklistMonitor = new BssidBlocklistMonitor(mContext, mWifiConnectivityHelper,
@@ -394,6 +413,8 @@ public class BssidBlocklistMonitorTest {
                 ABNORMAL_DISCONNECT_RESET_TIME_MS + 1);
         verify(mWifiScoreCard).resetBssidBlocklistStreak(TEST_SSID_1, TEST_BSSID_1,
                 BssidBlocklistMonitor.REASON_ABNORMAL_DISCONNECT);
+        verify(mWifiScoreCard).resetBssidBlocklistStreak(TEST_SSID_1, TEST_BSSID_1,
+                BssidBlocklistMonitor.REASON_FRAMEWORK_DISCONNECT_CONNECTED_SCORE);
     }
 
     /**
@@ -409,6 +430,20 @@ public class BssidBlocklistMonitorTest {
                 BssidBlocklistMonitor.REASON_ABNORMAL_DISCONNECT);
     }
 
+    /**
+     * Verify that the streak count for REASON_FRAMEWORK_DISCONNECT_CONNECTED_SCORE is not reset
+     * if insufficient time has passed.
+     */
+    @Test
+    public void testNetworkConnectionNotResetConnectedScoreStreak() {
+        when(mClock.getWallClockMillis()).thenReturn(ABNORMAL_DISCONNECT_RESET_TIME_MS);
+        mBssidBlocklistMonitor.handleBssidConnectionSuccess(TEST_BSSID_1, TEST_SSID_1);
+        verify(mWifiScoreCard).setBssidConnectionTimestampMs(TEST_SSID_1, TEST_BSSID_1,
+                ABNORMAL_DISCONNECT_RESET_TIME_MS);
+        verify(mWifiScoreCard, never()).resetBssidBlocklistStreak(TEST_SSID_1, TEST_BSSID_1,
+                BssidBlocklistMonitor.REASON_FRAMEWORK_DISCONNECT_CONNECTED_SCORE);
+    }
+
     /**
      * Verify that handleDhcpProvisioningSuccess resets appropriate blocklist streak counts.
      */
@@ -454,18 +489,23 @@ public class BssidBlocklistMonitorTest {
      */
     @Test
     public void testIncrementingBlocklistStreakCount() {
-        verifyAddTestBssidToBlocklist();
-        // verify that the blocklist streak is incremented
-        verify(mWifiScoreCard).incrementBssidBlocklistStreak(TEST_SSID_1, TEST_BSSID_1,
-                BssidBlocklistMonitor.REASON_AP_UNABLE_TO_HANDLE_NEW_STA);
+        for (Map.Entry<Integer, Integer> entry : BLOCK_REASON_TO_DISABLE_THRESHOLD_MAP.entrySet()) {
+            int reason = entry.getKey();
+            int threshold = entry.getValue();
+            when(mClock.getWallClockMillis()).thenReturn(0L);
+            handleBssidConnectionFailureMultipleTimes(TEST_BSSID_1, TEST_SSID_1, reason, threshold);
 
-        // Verify that TEST_BSSID_1 is removed from the blocklist after the timeout duration.
-        when(mClock.getWallClockMillis()).thenReturn(BASE_BLOCKLIST_DURATION + 1);
-        assertEquals(0, mBssidBlocklistMonitor.updateAndGetBssidBlocklist().size());
+            // verify that the blocklist streak is incremented
+            verify(mWifiScoreCard).incrementBssidBlocklistStreak(TEST_SSID_1, TEST_BSSID_1, reason);
 
-        // But the blacklist streak count is not cleared
-        verify(mWifiScoreCard, never()).resetBssidBlocklistStreak(TEST_SSID_1, TEST_BSSID_1,
-                BssidBlocklistMonitor.REASON_AP_UNABLE_TO_HANDLE_NEW_STA);
+            // Verify that TEST_BSSID_1 is removed from the blocklist after the timeout duration.
+            when(mClock.getWallClockMillis()).thenReturn(BASE_BLOCKLIST_DURATION + 1);
+            assertEquals(0, mBssidBlocklistMonitor.updateAndGetBssidBlocklist().size());
+
+            // But the blocklist streak count is not cleared
+            verify(mWifiScoreCard, never()).resetBssidBlocklistStreak(TEST_SSID_1, TEST_BSSID_1,
+                    reason);
+        }
     }
 
     /**
diff --git a/tests/wifitests/src/com/android/server/wifi/WifiScoreReportTest.java b/tests/wifitests/src/com/android/server/wifi/WifiScoreReportTest.java
index 954d4fe82..b85f223b7 100644
--- a/tests/wifitests/src/com/android/server/wifi/WifiScoreReportTest.java
+++ b/tests/wifitests/src/com/android/server/wifi/WifiScoreReportTest.java
@@ -20,16 +20,15 @@ import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 import static org.mockito.AdditionalAnswers.answerVoid;
-import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.anyInt;
-import static org.mockito.Mockito.anyLong;
 import static org.mockito.Mockito.atLeast;
 import static org.mockito.Mockito.atMost;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.spy;
@@ -782,7 +781,7 @@ public class WifiScoreReportTest extends WifiBaseTest {
     }
 
     /**
-     * Verify BSSID blocklist doesnot happen when score stays below threshold for less than the
+     * Verify BSSID blocklist does not happen when score stays below threshold for less than the
      * minimum duration
      */
     @Test
@@ -802,7 +801,7 @@ public class WifiScoreReportTest extends WifiBaseTest {
         mLooper.dispatchAll();
         mWifiScoreReport.stopConnectedNetworkScorer();
         mLooper.dispatchAll();
-        verify(mBssidBlocklistMonitor, never()).blockBssidForDurationMs(any(), any(), anyLong(),
+        verify(mBssidBlocklistMonitor, never()).handleBssidConnectionFailure(any(), any(),
                 anyInt(), anyInt());
     }
 
@@ -827,12 +826,12 @@ public class WifiScoreReportTest extends WifiBaseTest {
         mLooper.dispatchAll();
         mWifiScoreReport.stopConnectedNetworkScorer();
         mLooper.dispatchAll();
-        verify(mBssidBlocklistMonitor).blockBssidForDurationMs(any(), any(), anyLong(), anyInt(),
-                anyInt());
+        verify(mBssidBlocklistMonitor).handleBssidConnectionFailure(any(), any(),
+                eq(BssidBlocklistMonitor.REASON_FRAMEWORK_DISCONNECT_CONNECTED_SCORE), anyInt());
     }
 
     /**
-     * Verify BSSID blocklist doesnot happen when there is score flip flop
+     * Verify BSSID blocklist does not happen when there is score flip flop
      */
     @Test
     public void bssidBlockListDoesnotHappenWhenExitingIsReset() throws Exception {
@@ -854,7 +853,7 @@ public class WifiScoreReportTest extends WifiBaseTest {
         mLooper.dispatchAll();
         mWifiScoreReport.stopConnectedNetworkScorer();
         mLooper.dispatchAll();
-        verify(mBssidBlocklistMonitor, never()).blockBssidForDurationMs(any(), any(), anyLong(),
+        verify(mBssidBlocklistMonitor, never()).handleBssidConnectionFailure(any(), any(),
                 anyInt(), anyInt());
     }
 
-- 
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