/*
* Copyright (C) 2016 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.server.connectivity;
import android.content.Context;
import android.net.ConnectivityMetricsEvent;
import android.net.IIpConnectivityMetrics;
import android.net.INetdEventCallback;
import android.net.metrics.ApfProgramEvent;
import android.net.metrics.IpConnectivityLog;
import android.os.Binder;
import android.os.IBinder;
import android.os.Parcelable;
import android.os.Process;
import android.provider.Settings;
import android.text.TextUtils;
import android.text.format.DateUtils;
import android.util.ArrayMap;
import android.util.Base64;
import android.util.Log;
import com.android.internal.annotations.GuardedBy;
import com.android.internal.annotations.VisibleForTesting;
import com.android.internal.util.TokenBucket;
import com.android.server.SystemService;
import com.android.server.connectivity.metrics.IpConnectivityLogClass.IpConnectivityEvent;
import java.io.FileDescriptor;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
import java.util.function.ToIntFunction;
/** {@hide} */
final public class IpConnectivityMetrics extends SystemService {
private static final String TAG = IpConnectivityMetrics.class.getSimpleName();
private static final boolean DBG = false;
// The logical version numbers of ipconnectivity.proto, corresponding to the
// "version" field of IpConnectivityLog.
private static final int NYC = 0;
private static final int NYC_MR1 = 1;
private static final int NYC_MR2 = 2;
public static final int VERSION = NYC_MR2;
private static final String SERVICE_NAME = IpConnectivityLog.SERVICE_NAME;
// Default size of the event buffer. Once the buffer is full, incoming events are dropped.
private static final int DEFAULT_BUFFER_SIZE = 2000;
// Maximum size of the event buffer.
private static final int MAXIMUM_BUFFER_SIZE = DEFAULT_BUFFER_SIZE * 10;
private static final int MAXIMUM_CONNECT_LATENCY_RECORDS = 20000;
private static final int ERROR_RATE_LIMITED = -1;
// Lock ensuring that concurrent manipulations of the event buffer are correct.
// There are three concurrent operations to synchronize:
// - appending events to the buffer.
// - iterating throught the buffer.
// - flushing the buffer content and replacing it by a new buffer.
private final Object mLock = new Object();
@VisibleForTesting
public final Impl impl = new Impl();
private NetdEventListenerService mNetdListener;
@GuardedBy("mLock")
private ArrayList<ConnectivityMetricsEvent> mBuffer;
@GuardedBy("mLock")
private int mDropped;
@GuardedBy("mLock")
private int mCapacity;
@GuardedBy("mLock")
private final ArrayMap<Class<?>, TokenBucket> mBuckets = makeRateLimitingBuckets();
private final ToIntFunction<Context> mCapacityGetter;
public IpConnectivityMetrics(Context ctx, ToIntFunction<Context> capacityGetter) {
super(ctx);
mCapacityGetter = capacityGetter;
initBuffer();
}
public IpConnectivityMetrics(Context ctx) {
this(ctx, READ_BUFFER_SIZE);
}
@Override
public void onStart() {
if (DBG) Log.d(TAG, "onStart");
}
@Override
public void onBootPhase(int phase) {
if (phase == SystemService.PHASE_SYSTEM_SERVICES_READY) {
if (DBG) Log.d(TAG, "onBootPhase");
mNetdListener = new NetdEventListenerService(getContext());
publishBinderService(SERVICE_NAME, impl);
publishBinderService(mNetdListener.SERVICE_NAME, mNetdListener);
}
}
@VisibleForTesting
public int bufferCapacity() {
return mCapacityGetter.applyAsInt(getContext());
}
private void initBuffer() {
synchronized (mLock) {
mDropped = 0;
mCapacity = bufferCapacity();
mBuffer = new ArrayList<>(mCapacity);
}
}
private int append(ConnectivityMetricsEvent event) {
if (DBG) Log.d(TAG, "logEvent: " + event);
synchronized (mLock) {
final int left = mCapacity - mBuffer.size();
if (event == null) {
return left;
}
if (isRateLimited(event)) {
// Do not count as a dropped event. TODO: consider adding separate counter
return ERROR_RATE_LIMITED;
}
if (left == 0) {
mDropped++;
return 0;
}
mBuffer.add(event);
return left - 1;
}
}
private boolean isRateLimited(ConnectivityMetricsEvent event) {
TokenBucket tb = mBuckets.get(event.data.getClass());
return (tb != null) && !tb.get();
}
private String flushEncodedOutput() {
final ArrayList<ConnectivityMetricsEvent> events;
final int dropped;
synchronized (mLock) {
events = mBuffer;
dropped = mDropped;
initBuffer();
}
final List<IpConnectivityEvent> protoEvents = IpConnectivityEventBuilder.toProto(events);
if (mNetdListener != null) {
mNetdListener.flushStatistics(protoEvents);
}
final byte[] data;
try {
data = IpConnectivityEventBuilder.serialize(dropped, protoEvents);
} catch (IOException e) {
Log.e(TAG, "could not serialize events", e);
return "";
}
return Base64.encodeToString(data, Base64.DEFAULT);
}
/**
* Clears the event buffer and prints its content as a protobuf serialized byte array
* inside a base64 encoded string.
*/
private void cmdFlush(FileDescriptor fd, PrintWriter pw, String[] args) {
pw.print(flushEncodedOutput());
}
/**
* Prints the content of the event buffer, either using the events ASCII representation
* or using protobuf text format.
*/
private void cmdList(FileDescriptor fd, PrintWriter pw, String[] args) {
final ArrayList<ConnectivityMetricsEvent> events;
synchronized (mLock) {
events = new ArrayList(mBuffer);
}
if (args.length > 1 && args[1].equals("proto")) {
for (IpConnectivityEvent ev : IpConnectivityEventBuilder.toProto(events)) {
pw.print(ev.toString());
}
return;
}
for (ConnectivityMetricsEvent ev : events) {
pw.println(ev.toString());
}
}
private void cmdStats(FileDescriptor fd, PrintWriter pw, String[] args) {
synchronized (mLock) {
pw.println("Buffered events: " + mBuffer.size());
pw.println("Buffer capacity: " + mCapacity);
pw.println("Dropped events: " + mDropped);
}
if (mNetdListener != null) {
mNetdListener.dump(pw);
}
}
private void cmdDefault(FileDescriptor fd, PrintWriter pw, String[] args) {
if (args.length == 0) {
pw.println("No command");
return;
}
pw.println("Unknown command " + TextUtils.join(" ", args));
}
public final class Impl extends IIpConnectivityMetrics.Stub {
static final String CMD_FLUSH = "flush";
static final String CMD_LIST = "list";
static final String CMD_STATS = "stats";
static final String CMD_DUMPSYS = "-a"; // dumpsys.cpp dumps services with "-a" as arguments
static final String CMD_DEFAULT = CMD_STATS;
@Override
public int logEvent(ConnectivityMetricsEvent event) {
enforceConnectivityInternalPermission();
return append(event);
}
@Override
public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
enforceDumpPermission();
if (DBG) Log.d(TAG, "dumpsys " + TextUtils.join(" ", args));
final String cmd = (args.length > 0) ? args[0] : CMD_DEFAULT;
switch (cmd) {
case CMD_FLUSH:
cmdFlush(fd, pw, args);
return;
case CMD_DUMPSYS:
// Fallthrough to CMD_LIST when dumpsys.cpp dumps services states (bug reports)
case CMD_LIST:
cmdList(fd, pw, args);
return;
case CMD_STATS:
cmdStats(fd, pw, args);
return;
default:
cmdDefault(fd, pw, args);
}
}
private void enforceConnectivityInternalPermission() {
enforcePermission(android.Manifest.permission.CONNECTIVITY_INTERNAL);
}
private void enforceDumpPermission() {
enforcePermission(android.Manifest.permission.DUMP);
}
private void enforcePermission(String what) {
getContext().enforceCallingOrSelfPermission(what, "IpConnectivityMetrics");
}
private void enforceNetdEventListeningPermission() {
final int uid = Binder.getCallingUid();
if (uid != Process.SYSTEM_UID) {
throw new SecurityException(String.format("Uid %d has no permission to listen for"
+ " netd events.", uid));
}
}
@Override
public boolean registerNetdEventCallback(INetdEventCallback callback) {
enforceNetdEventListeningPermission();
if (mNetdListener == null) {
return false;
}
return mNetdListener.registerNetdEventCallback(callback);
}
@Override
public boolean unregisterNetdEventCallback() {
enforceNetdEventListeningPermission();
if (mNetdListener == null) {
// if the service is null, we aren't registered anyway
return true;
}
return mNetdListener.unregisterNetdEventCallback();
}
};
private static final ToIntFunction<Context> READ_BUFFER_SIZE = (ctx) -> {
int size = Settings.Global.getInt(ctx.getContentResolver(),
Settings.Global.CONNECTIVITY_METRICS_BUFFER_SIZE, DEFAULT_BUFFER_SIZE);
if (size <= 0) {
return DEFAULT_BUFFER_SIZE;
}
return Math.min(size, MAXIMUM_BUFFER_SIZE);
};
private static ArrayMap<Class<?>, TokenBucket> makeRateLimitingBuckets() {
ArrayMap<Class<?>, TokenBucket> map = new ArrayMap<>();
// one token every minute, 50 tokens max: burst of ~50 events every hour.
map.put(ApfProgramEvent.class, new TokenBucket((int)DateUtils.MINUTE_IN_MILLIS, 50));
return map;
}
}