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

1 files changed, 72 insertions, 0 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;
+}