Move data stall definitions out from Setting

From mainline perspective, we should use android flag api
instead of using Settings. Thus, move the definitions into
NetworkStack.

Bug:120013793
Test: atest NetworkStackTests SettingsBackupTest
Change-Id: I8e1fb5b47fff3bf624131ba1f5732daabd991e6d
Merged-In: I8e1fb5b47fff3bf624131ba1f5732daabd991e6d
Merged-In: I0a2a1e5d3de14ea86556ca471e26064df3481412

4 files changed, 155 insertions, 33 deletions

diff --git a/src/android/net/util/DataStallUtils.java b/src/android/net/util/DataStallUtils.java
new file mode 100644
index 0000000..b6dbeb1
--- /dev/null
+++ b/src/android/net/util/DataStallUtils.java
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.util;
+
+/**
+ * Collection of utilities for data stall.
+ */
+public class DataStallUtils {
+    /**
+     * Detect data stall via using dns timeout counts.
+     */
+    public static final int DATA_STALL_EVALUATION_TYPE_DNS = 1;
+    // Default configuration values for data stall detection.
+    public static final int DEFAULT_CONSECUTIVE_DNS_TIMEOUT_THRESHOLD = 5;
+    public static final int DEFAULT_DATA_STALL_MIN_EVALUATE_TIME_MS = 60 * 1000;
+    public static final int DEFAULT_DATA_STALL_VALID_DNS_TIME_THRESHOLD_MS = 30 * 60 * 1000;
+    /**
+     * The threshold value for the number of consecutive dns timeout events received to be a
+     * signal of data stall. The number of consecutive timeouts needs to be {@code >=} this
+     * threshold to be considered a data stall. Set the value to {@code <= 0} to disable. Note
+     * that the value should be {@code > 0} if the DNS data stall detection is enabled.
+     *
+     */
+    public static final String CONFIG_DATA_STALL_CONSECUTIVE_DNS_TIMEOUT_THRESHOLD =
+            "data_stall_consecutive_dns_timeout_threshold";
+
+    /**
+     * The minimal time interval in milliseconds for data stall reevaluation.
+     *
+     */
+    public static final String CONFIG_DATA_STALL_MIN_EVALUATE_INTERVAL =
+            "data_stall_min_evaluate_interval";
+
+    /**
+     * DNS timeouts older than this timeout (in milliseconds) are not considered for detecting
+     * a data stall.
+     *
+     */
+    public static final String CONFIG_DATA_STALL_VALID_DNS_TIME_THRESHOLD =
+            "data_stall_valid_dns_time_threshold";
+
+    /**
+     * Which data stall detection signal to use. This is a bitmask constructed by bitwise-or-ing
+     * (i.e. {@code |}) the DATA_STALL_EVALUATION_TYPE_* values.
+     *
+     * Type: int
+     * Valid values:
+     *   {@link #DATA_STALL_EVALUATION_TYPE_DNS} : Use dns as a signal.
+     */
+    public static final String CONFIG_DATA_STALL_EVALUATION_TYPE = "data_stall_evaluation_type";
+    public static final int DEFAULT_DATA_STALL_EVALUATION_TYPES = DATA_STALL_EVALUATION_TYPE_DNS;
+    // The default number of DNS events kept of the log kept for dns signal evaluation. Each event
+    // is represented by a {@link com.android.server.connectivity.NetworkMonitor#DnsResult} objects.
+    // It's also the size of array of {@link com.android.server.connectivity.nano.DnsEvent} kept in
+    // metrics. Note that increasing the size may cause statsd log buffer bust. Need to check the
+    // design in statsd when you try to increase the size.
+    public static final int DEFAULT_DNS_LOG_SIZE = 20;
+}
diff --git a/src/android/net/util/NetworkStackUtils.java b/src/android/net/util/NetworkStackUtils.java
index ee83a85..fa8f65e 100644
--- a/src/android/net/util/NetworkStackUtils.java
+++ b/src/android/net/util/NetworkStackUtils.java
@@ -31,6 +31,9 @@ import java.util.function.Predicate;
  * Collection of utilities for the network stack.
  */
 public class NetworkStackUtils {
+    // TODO: Refer to DeviceConfig definition.
+    public static final String NAMESPACE_CONNECTIVITY = "connectivity";
+
     static {
         System.loadLibrary("networkstackutilsjni");
     }
@@ -103,6 +106,24 @@ public class NetworkStackUtils {
     }
 
     /**
+     * Look up the value of a property for a particular namespace from {@link DeviceConfig}.
+     * @param namespace The namespace containing the property to look up.
+     * @param name The name of the property to look up.
+     * @param defaultValue The value to return if the property does not exist or has no non-null
+     *                     value.
+     * @return the corresponding value, or defaultValue if none exists.
+     */
+    public static int getDeviceConfigPropertyInt(@NonNull String namespace, @NonNull String name,
+            int defaultValue) {
+        String value = getDeviceConfigProperty(namespace, name, null /* defaultValue */);
+        try {
+            return (value != null) ? Integer.parseInt(value) : defaultValue;
+        } catch (NumberFormatException e) {
+            return defaultValue;
+        }
+    }
+
+    /**
      * Attaches a socket filter that accepts DHCP packets to the given socket.
      */
     public static native void attachDhcpFilter(FileDescriptor fd) throws SocketException;
diff --git a/src/com/android/server/connectivity/NetworkMonitor.java b/src/com/android/server/connectivity/NetworkMonitor.java
index 8f7d988..d34d526 100644
--- a/src/com/android/server/connectivity/NetworkMonitor.java
+++ b/src/com/android/server/connectivity/NetworkMonitor.java
@@ -32,8 +32,18 @@ import static android.net.metrics.ValidationProbeEvent.DNS_FAILURE;
 import static android.net.metrics.ValidationProbeEvent.DNS_SUCCESS;
 import static android.net.metrics.ValidationProbeEvent.PROBE_FALLBACK;
 import static android.net.metrics.ValidationProbeEvent.PROBE_PRIVDNS;
+import static android.net.util.DataStallUtils.CONFIG_DATA_STALL_CONSECUTIVE_DNS_TIMEOUT_THRESHOLD;
+import static android.net.util.DataStallUtils.CONFIG_DATA_STALL_EVALUATION_TYPE;
+import static android.net.util.DataStallUtils.CONFIG_DATA_STALL_MIN_EVALUATE_INTERVAL;
+import static android.net.util.DataStallUtils.CONFIG_DATA_STALL_VALID_DNS_TIME_THRESHOLD;
+import static android.net.util.DataStallUtils.DATA_STALL_EVALUATION_TYPE_DNS;
+import static android.net.util.DataStallUtils.DEFAULT_CONSECUTIVE_DNS_TIMEOUT_THRESHOLD;
+import static android.net.util.DataStallUtils.DEFAULT_DATA_STALL_EVALUATION_TYPES;
+import static android.net.util.DataStallUtils.DEFAULT_DATA_STALL_MIN_EVALUATE_TIME_MS;
+import static android.net.util.DataStallUtils.DEFAULT_DATA_STALL_VALID_DNS_TIME_THRESHOLD_MS;
+import static android.net.util.DataStallUtils.DEFAULT_DNS_LOG_SIZE;
+import static android.net.util.NetworkStackUtils.NAMESPACE_CONNECTIVITY;
 import static android.net.util.NetworkStackUtils.isEmpty;
-import static android.provider.Settings.Global.DATA_STALL_EVALUATION_TYPE_DNS;
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
@@ -60,6 +70,7 @@ import android.net.metrics.NetworkEvent;
 import android.net.metrics.ValidationProbeEvent;
 import android.net.shared.NetworkMonitorUtils;
 import android.net.shared.PrivateDnsConfig;
+import android.net.util.NetworkStackUtils;
 import android.net.util.SharedLog;
 import android.net.util.Stopwatch;
 import android.net.wifi.WifiInfo;
@@ -126,18 +137,6 @@ public class NetworkMonitor extends StateMachine {
 
     private static final int SOCKET_TIMEOUT_MS = 10000;
     private static final int PROBE_TIMEOUT_MS  = 3000;
-
-    // Default configuration values for data stall detection.
-    private static final int DEFAULT_CONSECUTIVE_DNS_TIMEOUT_THRESHOLD = 5;
-    private static final int DEFAULT_DATA_STALL_MIN_EVALUATE_TIME_MS = 60 * 1000;
-    private static final int DEFAULT_DATA_STALL_VALID_DNS_TIME_THRESHOLD_MS = 30 * 60 * 1000;
-
-    private static final int DEFAULT_DATA_STALL_EVALUATION_TYPES =
-            DATA_STALL_EVALUATION_TYPE_DNS;
-    // Reevaluate it as intending to increase the number. Larger log size may cause statsd
-    // log buffer bust and have stats log lost.
-    private static final int DEFAULT_DNS_LOG_SIZE = 20;
-
     enum EvaluationResult {
         VALIDATED(true),
         CAPTIVE_PORTAL(false);
@@ -388,7 +387,7 @@ public class NetworkMonitor extends StateMachine {
         mDnsStallDetector = new DnsStallDetector(mConsecutiveDnsTimeoutThreshold);
         mDataStallMinEvaluateTime = getDataStallMinEvaluateTime();
         mDataStallValidDnsTimeThreshold = getDataStallValidDnsTimeThreshold();
-        mDataStallEvaluationType = getDataStallEvalutionType();
+        mDataStallEvaluationType = getDataStallEvaluationType();
 
         // Provide empty LinkProperties and NetworkCapabilities to make sure they are never null,
         // even before notifyNetworkConnected.
@@ -1185,25 +1184,26 @@ public class NetworkMonitor extends StateMachine {
     }
 
     private int getConsecutiveDnsTimeoutThreshold() {
-        return mDependencies.getSetting(mContext,
-                Settings.Global.DATA_STALL_CONSECUTIVE_DNS_TIMEOUT_THRESHOLD,
+        return mDependencies.getDeviceConfigPropertyInt(NAMESPACE_CONNECTIVITY,
+                CONFIG_DATA_STALL_CONSECUTIVE_DNS_TIMEOUT_THRESHOLD,
                 DEFAULT_CONSECUTIVE_DNS_TIMEOUT_THRESHOLD);
     }
 
     private int getDataStallMinEvaluateTime() {
-        return mDependencies.getSetting(mContext,
-                Settings.Global.DATA_STALL_MIN_EVALUATE_INTERVAL,
+        return mDependencies.getDeviceConfigPropertyInt(NAMESPACE_CONNECTIVITY,
+                CONFIG_DATA_STALL_MIN_EVALUATE_INTERVAL,
                 DEFAULT_DATA_STALL_MIN_EVALUATE_TIME_MS);
     }
 
     private int getDataStallValidDnsTimeThreshold() {
-        return mDependencies.getSetting(mContext,
-                Settings.Global.DATA_STALL_VALID_DNS_TIME_THRESHOLD,
+        return mDependencies.getDeviceConfigPropertyInt(NAMESPACE_CONNECTIVITY,
+                CONFIG_DATA_STALL_VALID_DNS_TIME_THRESHOLD,
                 DEFAULT_DATA_STALL_VALID_DNS_TIME_THRESHOLD_MS);
     }
 
-    private int getDataStallEvalutionType() {
-        return mDependencies.getSetting(mContext, Settings.Global.DATA_STALL_EVALUATION_TYPE,
+    private int getDataStallEvaluationType() {
+        return mDependencies.getDeviceConfigPropertyInt(NAMESPACE_CONNECTIVITY,
+                CONFIG_DATA_STALL_EVALUATION_TYPE,
                 DEFAULT_DATA_STALL_EVALUATION_TYPES);
     }
 
@@ -1726,6 +1726,33 @@ public class NetworkMonitor extends StateMachine {
             return value != null ? value : defaultValue;
         }
 
+        /**
+         * Look up the value of a property in DeviceConfig.
+         * @param namespace The namespace containing the property to look up.
+         * @param name The name of the property to look up.
+         * @param defaultValue The value to return if the property does not exist or has no non-null
+         *                     value.
+         * @return the corresponding value, or defaultValue if none exists.
+         */
+        @Nullable
+        public String getDeviceConfigProperty(@NonNull String namespace, @NonNull String name,
+                @Nullable String defaultValue) {
+            return NetworkStackUtils.getDeviceConfigProperty(namespace, name, defaultValue);
+        }
+
+        /**
+         * Look up the value of a property in DeviceConfig.
+         * @param namespace The namespace containing the property to look up.
+         * @param name The name of the property to look up.
+         * @param defaultValue The value to return if the property does not exist or has no non-null
+         *                     value.
+         * @return the corresponding value, or defaultValue if none exists.
+         */
+        public int getDeviceConfigPropertyInt(@NonNull String namespace, @NonNull String name,
+                int defaultValue) {
+            return NetworkStackUtils.getDeviceConfigPropertyInt(namespace, name, defaultValue);
+        }
+
         public static final Dependencies DEFAULT = new Dependencies();
     }
 
diff --git a/tests/src/com/android/server/connectivity/NetworkMonitorTest.java b/tests/src/com/android/server/connectivity/NetworkMonitorTest.java
index 6665aae..9f6c7f8 100644
--- a/tests/src/com/android/server/connectivity/NetworkMonitorTest.java
+++ b/tests/src/com/android/server/connectivity/NetworkMonitorTest.java
@@ -21,7 +21,11 @@ import static android.net.INetworkMonitor.NETWORK_TEST_RESULT_INVALID;
 import static android.net.INetworkMonitor.NETWORK_TEST_RESULT_PARTIAL_CONNECTIVITY;
 import static android.net.INetworkMonitor.NETWORK_TEST_RESULT_VALID;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_INTERNET;
-import static android.provider.Settings.Global.DATA_STALL_EVALUATION_TYPE_DNS;
+import static android.net.util.DataStallUtils.CONFIG_DATA_STALL_CONSECUTIVE_DNS_TIMEOUT_THRESHOLD;
+import static android.net.util.DataStallUtils.CONFIG_DATA_STALL_EVALUATION_TYPE;
+import static android.net.util.DataStallUtils.CONFIG_DATA_STALL_MIN_EVALUATE_INTERVAL;
+import static android.net.util.DataStallUtils.CONFIG_DATA_STALL_VALID_DNS_TIME_THRESHOLD;
+import static android.net.util.DataStallUtils.DATA_STALL_EVALUATION_TYPE_DNS;
 
 import static junit.framework.Assert.assertEquals;
 import static junit.framework.Assert.assertFalse;
@@ -114,7 +118,6 @@ public class NetworkMonitorTest {
     private @Captor ArgumentCaptor<String> mNetworkTestedRedirectUrlCaptor;
 
     private static final int TEST_NETID = 4242;
-
     private static final String TEST_HTTP_URL = "http://www.google.com/gen_204";
     private static final String TEST_HTTPS_URL = "https://www.google.com/gen_204";
     private static final String TEST_FALLBACK_URL = "http://fallback.google.com/gen_204";
@@ -593,24 +596,23 @@ public class NetworkMonitorTest {
     }
 
     private void setDataStallEvaluationType(int type) {
-        when(mDependencies.getSetting(any(),
-            eq(Settings.Global.DATA_STALL_EVALUATION_TYPE), anyInt())).thenReturn(type);
+        when(mDependencies.getDeviceConfigPropertyInt(any(),
+            eq(CONFIG_DATA_STALL_EVALUATION_TYPE), anyInt())).thenReturn(type);
     }
 
     private void setMinDataStallEvaluateInterval(int time) {
-        when(mDependencies.getSetting(any(),
-            eq(Settings.Global.DATA_STALL_MIN_EVALUATE_INTERVAL), anyInt())).thenReturn(time);
+        when(mDependencies.getDeviceConfigPropertyInt(any(),
+            eq(CONFIG_DATA_STALL_MIN_EVALUATE_INTERVAL), anyInt())).thenReturn(time);
     }
 
     private void setValidDataStallDnsTimeThreshold(int time) {
-        when(mDependencies.getSetting(any(),
-            eq(Settings.Global.DATA_STALL_VALID_DNS_TIME_THRESHOLD), anyInt())).thenReturn(time);
+        when(mDependencies.getDeviceConfigPropertyInt(any(),
+            eq(CONFIG_DATA_STALL_VALID_DNS_TIME_THRESHOLD), anyInt())).thenReturn(time);
     }
 
     private void setConsecutiveDnsTimeoutThreshold(int num) {
-        when(mDependencies.getSetting(any(),
-            eq(Settings.Global.DATA_STALL_CONSECUTIVE_DNS_TIMEOUT_THRESHOLD), anyInt()))
-            .thenReturn(num);
+        when(mDependencies.getDeviceConfigPropertyInt(any(),
+            eq(CONFIG_DATA_STALL_CONSECUTIVE_DNS_TIMEOUT_THRESHOLD), anyInt())).thenReturn(num);
     }
 
     private void setFallbackUrl(String url) {