Call getDataSaverEnabled from isUidNetworkingBlocked

This reduces unnecessary bpf map read

Bug: 328732146
Test: TH
Change-Id: I7652bee99c1d733bae38508d7d6092c90678dc42
diff --git a/framework/src/android/net/ConnectivityManager.java b/framework/src/android/net/ConnectivityManager.java
index 3f5d923..b1e636d 100644
--- a/framework/src/android/net/ConnectivityManager.java
+++ b/framework/src/android/net/ConnectivityManager.java
@@ -6293,7 +6293,7 @@
         // the status is not synchronized.
         // On V+, the data saver status is set by platform code when enabling/disabling
         // data saver, which is synchronized.
-        return reader.isUidNetworkingBlocked(uid, isNetworkMetered, reader.getDataSaverEnabled());
+        return reader.isUidNetworkingBlocked(uid, isNetworkMetered);
     }
 
     /** @hide */
diff --git a/framework/src/android/net/NetworkStackBpfNetMaps.java b/framework/src/android/net/NetworkStackBpfNetMaps.java
index 72da328..346c997 100644
--- a/framework/src/android/net/NetworkStackBpfNetMaps.java
+++ b/framework/src/android/net/NetworkStackBpfNetMaps.java
@@ -234,17 +234,17 @@
     /**
      * Return whether the network is blocked by firewall chains for the given uid.
      *
+     * Note that {@link #getDataSaverEnabled()} has a latency before V.
+     *
      * @param uid The target uid.
      * @param isNetworkMetered Whether the target network is metered.
-     * @param isDataSaverEnabled Whether the data saver is enabled.
      *
      * @return True if the network is blocked. Otherwise, false.
      * @throws ServiceSpecificException if the read fails.
      *
      * @hide
      */
-    public boolean isUidNetworkingBlocked(final int uid, boolean isNetworkMetered,
-            boolean isDataSaverEnabled) {
+    public boolean isUidNetworkingBlocked(final int uid, boolean isNetworkMetered) {
         throwIfPreT("isUidBlockedByFirewallChains is not available on pre-T devices");
 
         final long uidRuleConfig;
@@ -267,12 +267,18 @@
         if (!isNetworkMetered) return false;
         if ((uidMatch & PENALTY_BOX_MATCH) != 0) return true;
         if ((uidMatch & HAPPY_BOX_MATCH) != 0) return false;
-        return isDataSaverEnabled;
+        return getDataSaverEnabled();
     }
 
     /**
      * Get Data Saver enabled or disabled
      *
+     * Note that before V, the data saver status in bpf is written by ConnectivityService
+     * when receiving {@link ConnectivityManager#ACTION_RESTRICT_BACKGROUND_CHANGED}. Thus,
+     * the status is not synchronized.
+     * On V+, the data saver status is set by platform code when enabling/disabling
+     * data saver, which is synchronized.
+     *
      * @return whether Data Saver is enabled or disabled.
      * @throws ServiceSpecificException in case of failure, with an error code indicating the
      *                                  cause of the failure.
diff --git a/tests/unit/java/android/net/NetworkStackBpfNetMapsTest.kt b/tests/unit/java/android/net/NetworkStackBpfNetMapsTest.kt
index 9238c86..ca98269 100644
--- a/tests/unit/java/android/net/NetworkStackBpfNetMapsTest.kt
+++ b/tests/unit/java/android/net/NetworkStackBpfNetMapsTest.kt
@@ -123,11 +123,17 @@
         testConfigurationMap.updateEntry(UID_RULES_CONFIGURATION_KEY, U32(newConfig))
     }
 
-    fun isUidNetworkingBlocked(uid: Int, metered: Boolean = false, dataSaver: Boolean = false) =
-            bpfNetMapsReader.isUidNetworkingBlocked(uid, metered, dataSaver)
+    private fun mockDataSaverEnabled(enabled: Boolean) {
+        val dataSaverValue = if (enabled) {DATA_SAVER_ENABLED} else {DATA_SAVER_DISABLED}
+        testDataSaverEnabledMap.updateEntry(DATA_SAVER_ENABLED_KEY, U8(dataSaverValue))
+    }
+
+    fun isUidNetworkingBlocked(uid: Int, metered: Boolean = false) =
+            bpfNetMapsReader.isUidNetworkingBlocked(uid, metered)
 
     @Test
     fun testIsUidNetworkingBlockedByFirewallChains_allowChain() {
+        mockDataSaverEnabled(enabled = false)
         // With everything disabled by default, verify the return value is false.
         testConfigurationMap.updateEntry(UID_RULES_CONFIGURATION_KEY, U32(0))
         assertFalse(isUidNetworkingBlocked(TEST_UID1))
@@ -147,6 +153,7 @@
 
     @Test
     fun testIsUidNetworkingBlockedByFirewallChains_denyChain() {
+        mockDataSaverEnabled(enabled = false)
         // Enable standby chain but does not provide denied list. Verify the network is allowed
         // for all uids.
         testConfigurationMap.updateEntry(UID_RULES_CONFIGURATION_KEY, U32(0))
@@ -168,12 +175,14 @@
         testConfigurationMap.updateEntry(UID_RULES_CONFIGURATION_KEY, U32(0))
         mockChainEnabled(ConnectivityManager.FIREWALL_CHAIN_POWERSAVE, true)
         mockChainEnabled(ConnectivityManager.FIREWALL_CHAIN_STANDBY, true)
+        mockDataSaverEnabled(enabled = false)
         assertTrue(isUidNetworkingBlocked(TEST_UID1))
     }
 
     @IgnoreUpTo(VERSION_CODES.S_V2)
     @Test
     fun testIsUidNetworkingBlockedByDataSaver() {
+        mockDataSaverEnabled(enabled = false)
         // With everything disabled by default, verify the return value is false.
         testConfigurationMap.updateEntry(UID_RULES_CONFIGURATION_KEY, U32(0))
         assertFalse(isUidNetworkingBlocked(TEST_UID1, metered = true))
@@ -186,10 +195,11 @@
 
         // Enable data saver, verify the network is blocked for uid1, uid2, but uid3 in happy box
         // is not affected.
+        mockDataSaverEnabled(enabled = true)
         testUidOwnerMap.updateEntry(S32(TEST_UID3), UidOwnerValue(NO_IIF, HAPPY_BOX_MATCH))
-        assertTrue(isUidNetworkingBlocked(TEST_UID1, metered = true, dataSaver = true))
-        assertTrue(isUidNetworkingBlocked(TEST_UID2, metered = true, dataSaver = true))
-        assertFalse(isUidNetworkingBlocked(TEST_UID3, metered = true, dataSaver = true))
+        assertTrue(isUidNetworkingBlocked(TEST_UID1, metered = true))
+        assertTrue(isUidNetworkingBlocked(TEST_UID2, metered = true))
+        assertFalse(isUidNetworkingBlocked(TEST_UID3, metered = true))
 
         // Add uid1 to happy box as well, verify nothing is changed because penalty box has higher
         // priority.
@@ -197,18 +207,19 @@
             S32(TEST_UID1),
             UidOwnerValue(NO_IIF, PENALTY_BOX_MATCH or HAPPY_BOX_MATCH)
         )
-        assertTrue(isUidNetworkingBlocked(TEST_UID1, metered = true, dataSaver = true))
-        assertTrue(isUidNetworkingBlocked(TEST_UID2, metered = true, dataSaver = true))
-        assertFalse(isUidNetworkingBlocked(TEST_UID3, metered = true, dataSaver = true))
+        assertTrue(isUidNetworkingBlocked(TEST_UID1, metered = true))
+        assertTrue(isUidNetworkingBlocked(TEST_UID2, metered = true))
+        assertFalse(isUidNetworkingBlocked(TEST_UID3, metered = true))
 
         // Enable doze mode, verify uid3 is blocked even if it is in happy box.
         mockChainEnabled(ConnectivityManager.FIREWALL_CHAIN_DOZABLE, true)
-        assertTrue(isUidNetworkingBlocked(TEST_UID1, metered = true, dataSaver = true))
-        assertTrue(isUidNetworkingBlocked(TEST_UID2, metered = true, dataSaver = true))
-        assertTrue(isUidNetworkingBlocked(TEST_UID3, metered = true, dataSaver = true))
+        assertTrue(isUidNetworkingBlocked(TEST_UID1, metered = true))
+        assertTrue(isUidNetworkingBlocked(TEST_UID2, metered = true))
+        assertTrue(isUidNetworkingBlocked(TEST_UID3, metered = true))
 
         // Disable doze mode and data saver, only uid1 which is in penalty box is blocked.
         mockChainEnabled(ConnectivityManager.FIREWALL_CHAIN_DOZABLE, false)
+        mockDataSaverEnabled(enabled = false)
         assertTrue(isUidNetworkingBlocked(TEST_UID1, metered = true))
         assertFalse(isUidNetworkingBlocked(TEST_UID2, metered = true))
         assertFalse(isUidNetworkingBlocked(TEST_UID3, metered = true))