Add exponential backoff on the network level

Use the number of BSSIDs in the BSSID blocklist to determine how long we
should temporarily disable networks.

This check to re-enable networks is done every time before network
selection:
- if the elapsed time from now to the time the network was disabled is
greater than or equal to a timeout then re-enable the network.

The timeout calculated based on how many BSSIDs are in the BSSID
blocklist:
- 0 BSSID = 0ms (re-enable immediately)
- 1 BSSID = 5 minutes
- 2 BSSIDs = 10 minutes
- 3 BSSIDS = 20 minutes
...

Bug: 139287182
Test: atest FrameworksWifiTests
Change-Id: I009c5410898b09045b42adf4a1f48c05a268fba3

2 files changed, 25 insertions, 1 deletions

diff --git a/service/java/com/android/server/wifi/BssidBlocklistMonitor.java b/service/java/com/android/server/wifi/BssidBlocklistMonitor.java
index 7aab09cc5..2f0ba5ff1 100644
--- a/service/java/com/android/server/wifi/BssidBlocklistMonitor.java
+++ b/service/java/com/android/server/wifi/BssidBlocklistMonitor.java
@@ -283,6 +283,15 @@ public class BssidBlocklistMonitor {
     }
 
     /**
+     * @param ssid
+     * @return the number of BSSIDs currently in the blocklist for the |ssid|.
+     */
+    public int getNumBlockedBssidsForSsid(@NonNull String ssid) {
+        return (int) updateAndGetBssidBlocklistInternal()
+                .filter(entry -> ssid.equals(entry.ssid)).count();
+    }
+
+    /**
      * Gets the BSSIDs that are currently in the blocklist.
      * @return Set of BSSIDs currently in the blocklist
      */
diff --git a/service/java/com/android/server/wifi/WifiConfigManager.java b/service/java/com/android/server/wifi/WifiConfigManager.java
index 18b5562b3..e2dd98522 100644
--- a/service/java/com/android/server/wifi/WifiConfigManager.java
+++ b/service/java/com/android/server/wifi/WifiConfigManager.java
@@ -219,6 +219,12 @@ public class WifiConfigManager {
     private static final int SCAN_RESULT_MAXIMUM_AGE_MS = 40000;
 
     /**
+     * Maximum number of blocked BSSIDs per SSID used for calcualting the duration of temporarily
+     * disabling a network.
+     */
+    private static final int MAX_BLOCKED_BSSID_PER_NETWORK = 10;
+
+    /**
      * Maximum age of frequencies last seen to be included in pno scans. (30 days)
      */
     @VisibleForTesting
@@ -1892,7 +1898,16 @@ public class WifiConfigManager {
             long timeDifferenceMs =
                     mClock.getElapsedSinceBootMillis() - networkStatus.getDisableTime();
             int disableReason = networkStatus.getNetworkSelectionDisableReason();
-            long disableTimeoutMs = NETWORK_SELECTION_DISABLE_TIMEOUT_MS[disableReason];
+            int blockedBssids = Math.min(MAX_BLOCKED_BSSID_PER_NETWORK,
+                    mWifiInjector.getBssidBlocklistMonitor()
+                            .getNumBlockedBssidsForSsid(config.SSID));
+            // if no BSSIDs are blocked then we should keep trying to connect to something
+            long disableTimeoutMs = 0;
+            if (blockedBssids > 0) {
+                double multiplier = Math.pow(2.0, blockedBssids - 1.0);
+                disableTimeoutMs = (long) (NETWORK_SELECTION_DISABLE_TIMEOUT_MS[disableReason]
+                        * multiplier);
+            }
             if (timeDifferenceMs >= disableTimeoutMs) {
                 return updateNetworkSelectionStatus(
                         config, NetworkSelectionStatus.NETWORK_SELECTION_ENABLE);