Create a new utils for connectivity related settings

ConnectivitySettingsManager and CtsNetUtils are doing the same
thing to set/get private DNS related settings.
To prevent making the duplication code in two places, having a
lib for them to call.

Bug: 185311744
Test: atest CtsNetTestCases CtsNetTestCasesLatestSdk
Original-Change: https://android-review.googlesource.com/1715693
Merged-In: Ia192520039b187b24e0a7b8bf9509bb10859ace0
Change-Id: Ia192520039b187b24e0a7b8bf9509bb10859ace0

1 files changed, 127 insertions, 0 deletions

diff --git a/common/framework/com/android/net/module/util/ConnectivitySettingsUtils.java b/common/framework/com/android/net/module/util/ConnectivitySettingsUtils.java
new file mode 100644
index 00000000..b7eb70b0
--- /dev/null
+++ b/common/framework/com/android/net/module/util/ConnectivitySettingsUtils.java
@@ -0,0 +1,127 @@
+/*
+ * Copyright (C) 2021 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 com.android.net.module.util;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.content.ContentResolver;
+import android.content.Context;
+import android.provider.Settings;
+import android.text.TextUtils;
+
+/**
+ * Collection of connectivity settings utilities.
+ *
+ * @hide
+ */
+public class ConnectivitySettingsUtils {
+    public static final int PRIVATE_DNS_MODE_OFF = 1;
+    public static final int PRIVATE_DNS_MODE_OPPORTUNISTIC = 2;
+    public static final int PRIVATE_DNS_MODE_PROVIDER_HOSTNAME = 3;
+
+    public static final String PRIVATE_DNS_DEFAULT_MODE = "private_dns_default_mode";
+    public static final String PRIVATE_DNS_MODE = "private_dns_mode";
+    public static final String PRIVATE_DNS_MODE_OFF_STRING = "off";
+    public static final String PRIVATE_DNS_MODE_OPPORTUNISTIC_STRING = "opportunistic";
+    public static final String PRIVATE_DNS_MODE_PROVIDER_HOSTNAME_STRING = "hostname";
+    public static final String PRIVATE_DNS_SPECIFIER = "private_dns_specifier";
+
+    /**
+     * Get private DNS mode as string.
+     *
+     * @param mode One of the private DNS values.
+     * @return A string of private DNS mode.
+     */
+    public static String getPrivateDnsModeAsString(int mode) {
+        switch (mode) {
+            case PRIVATE_DNS_MODE_OFF:
+                return PRIVATE_DNS_MODE_OFF_STRING;
+            case PRIVATE_DNS_MODE_OPPORTUNISTIC:
+                return PRIVATE_DNS_MODE_OPPORTUNISTIC_STRING;
+            case PRIVATE_DNS_MODE_PROVIDER_HOSTNAME:
+                return PRIVATE_DNS_MODE_PROVIDER_HOSTNAME_STRING;
+            default:
+                throw new IllegalArgumentException("Invalid private dns mode: " + mode);
+        }
+    }
+
+    private static int getPrivateDnsModeAsInt(String mode) {
+        switch (mode) {
+            case "off":
+                return PRIVATE_DNS_MODE_OFF;
+            case "hostname":
+                return PRIVATE_DNS_MODE_PROVIDER_HOSTNAME;
+            case "opportunistic":
+                return PRIVATE_DNS_MODE_OPPORTUNISTIC;
+            default:
+                throw new IllegalArgumentException("Invalid private dns mode: " + mode);
+        }
+    }
+
+    /**
+     * Get private DNS mode from settings.
+     *
+     * @param context The Context to query the private DNS mode from settings.
+     * @return An integer of private DNS mode.
+     */
+    public static int getPrivateDnsMode(@NonNull Context context) {
+        final ContentResolver cr = context.getContentResolver();
+        String mode = Settings.Global.getString(cr, PRIVATE_DNS_MODE);
+        if (TextUtils.isEmpty(mode)) mode = Settings.Global.getString(cr, PRIVATE_DNS_DEFAULT_MODE);
+        // If both PRIVATE_DNS_MODE and PRIVATE_DNS_DEFAULT_MODE are not set, choose
+        // PRIVATE_DNS_MODE_OPPORTUNISTIC as default mode.
+        if (TextUtils.isEmpty(mode)) return PRIVATE_DNS_MODE_OPPORTUNISTIC;
+        return getPrivateDnsModeAsInt(mode);
+    }
+
+    /**
+     * Set private DNS mode to settings.
+     *
+     * @param context The {@link Context} to set the private DNS mode.
+     * @param mode The private dns mode. This should be one of the PRIVATE_DNS_MODE_* constants.
+     */
+    public static void setPrivateDnsMode(@NonNull Context context, int mode) {
+        if (!(mode == PRIVATE_DNS_MODE_OFF
+                || mode == PRIVATE_DNS_MODE_OPPORTUNISTIC
+                || mode == PRIVATE_DNS_MODE_PROVIDER_HOSTNAME)) {
+            throw new IllegalArgumentException("Invalid private dns mode: " + mode);
+        }
+        Settings.Global.putString(context.getContentResolver(), PRIVATE_DNS_MODE,
+                getPrivateDnsModeAsString(mode));
+    }
+
+    /**
+     * Get specific private dns provider name from {@link Settings}.
+     *
+     * @param context The {@link Context} to query the setting.
+     * @return The specific private dns provider name, or null if no setting value.
+     */
+    @Nullable
+    public static String getPrivateDnsHostname(@NonNull Context context) {
+        return Settings.Global.getString(context.getContentResolver(), PRIVATE_DNS_SPECIFIER);
+    }
+
+    /**
+     * Set specific private dns provider name to {@link Settings}.
+     *
+     * @param context The {@link Context} to set the setting.
+     * @param specifier The specific private dns provider name.
+     */
+    public static void setPrivateDnsHostname(@NonNull Context context, @Nullable String specifier) {
+        Settings.Global.putString(context.getContentResolver(), PRIVATE_DNS_SPECIFIER, specifier);
+    }
+}