/*
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* Copyright (C) 2019 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package android.net.util;
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import android.annotation.NonNull;
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import android.content.Context;
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import android.content.res.Resources;
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import android.net.NetworkCapabilities;
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import android.text.TextUtils;
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import android.util.AndroidRuntimeException;
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import com.android.internal.R;
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/**
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* Collection of utilities for socket keepalive offload.
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*
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* @hide
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*/
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public final class KeepaliveUtils {
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public static final String TAG = "KeepaliveUtils";
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public static class KeepaliveDeviceConfigurationException extends AndroidRuntimeException {
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public KeepaliveDeviceConfigurationException(final String msg) {
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super(msg);
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}
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}
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/**
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* Read supported keepalive count for each transport type from overlay resource. This should be
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* used to create a local variable store of resource customization, and use it as the input for
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* {@link getSupportedKeepalivesForNetworkCapabilities}.
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*
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* @param context The context to read resource from.
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* @return An array of supported keepalive count for each transport type.
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*/
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@NonNull
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public static int[] getSupportedKeepalives(@NonNull Context context) {
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String[] res = null;
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try {
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res = context.getResources().getStringArray(
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R.array.config_networkSupportedKeepaliveCount);
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} catch (Resources.NotFoundException unused) {
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}
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if (res == null) throw new KeepaliveDeviceConfigurationException("invalid resource");
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final int[] ret = new int[NetworkCapabilities.MAX_TRANSPORT + 1];
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for (final String row : res) {
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if (TextUtils.isEmpty(row)) {
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throw new KeepaliveDeviceConfigurationException("Empty string");
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}
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final String[] arr = row.split(",");
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if (arr.length != 2) {
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throw new KeepaliveDeviceConfigurationException("Invalid parameter length");
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}
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int transport;
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int supported;
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try {
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transport = Integer.parseInt(arr[0]);
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supported = Integer.parseInt(arr[1]);
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} catch (NumberFormatException e) {
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throw new KeepaliveDeviceConfigurationException("Invalid number format");
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}
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if (!NetworkCapabilities.isValidTransport(transport)) {
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throw new KeepaliveDeviceConfigurationException("Invalid transport " + transport);
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}
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if (supported < 0) {
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throw new KeepaliveDeviceConfigurationException(
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"Invalid supported count " + supported + " for "
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+ NetworkCapabilities.transportNameOf(transport));
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}
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ret[transport] = supported;
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}
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return ret;
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}
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/**
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* Get supported keepalive count for the given {@link NetworkCapabilities}.
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*
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* @param supportedKeepalives An array of supported keepalive count for each transport type.
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* @param nc The {@link NetworkCapabilities} of the network the socket keepalive is on.
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*
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* @return Supported keepalive count for the given {@link NetworkCapabilities}.
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*/
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public static int getSupportedKeepalivesForNetworkCapabilities(
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@NonNull int[] supportedKeepalives, @NonNull NetworkCapabilities nc) {
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final int[] transports = nc.getTransportTypes();
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if (transports.length == 0) return 0;
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int supportedCount = supportedKeepalives[transports[0]];
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// Iterate through transports and return minimum supported value.
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for (final int transport : transports) {
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if (supportedCount > supportedKeepalives[transport]) {
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supportedCount = supportedKeepalives[transport];
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}
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}
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return supportedCount;
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}
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}
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