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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.server.connectivity;
     18 
     19 import android.content.Context;
     20 import android.net.ConnectivityMetricsEvent;
     21 import android.net.IIpConnectivityMetrics;
     22 import android.net.metrics.IpConnectivityLog;
     23 import android.os.IBinder;
     24 import android.os.Parcelable;
     25 import android.text.TextUtils;
     26 import android.util.Base64;
     27 import android.util.Log;
     28 import com.android.internal.annotations.GuardedBy;
     29 import com.android.internal.annotations.VisibleForTesting;
     30 import com.android.server.SystemService;
     31 import java.io.FileDescriptor;
     32 import java.io.IOException;
     33 import java.io.PrintWriter;
     34 import java.util.ArrayList;
     35 
     36 import static com.android.server.connectivity.metrics.IpConnectivityLogClass.IpConnectivityEvent;
     37 
     38 /** {@hide} */
     39 final public class IpConnectivityMetrics extends SystemService {
     40     private static final String TAG = IpConnectivityMetrics.class.getSimpleName();
     41     private static final boolean DBG = false;
     42 
     43     private static final String SERVICE_NAME = IpConnectivityLog.SERVICE_NAME;
     44 
     45     // Default size of the event buffer. Once the buffer is full, incoming events are dropped.
     46     private static final int DEFAULT_BUFFER_SIZE = 2000;
     47 
     48     // Lock ensuring that concurrent manipulations of the event buffer are correct.
     49     // There are three concurrent operations to synchronize:
     50     //  - appending events to the buffer.
     51     //  - iterating throught the buffer.
     52     //  - flushing the buffer content and replacing it by a new buffer.
     53     private final Object mLock = new Object();
     54 
     55     @VisibleForTesting
     56     public final Impl impl = new Impl();
     57     private DnsEventListenerService mDnsListener;
     58 
     59     @GuardedBy("mLock")
     60     private ArrayList<ConnectivityMetricsEvent> mBuffer;
     61     @GuardedBy("mLock")
     62     private int mDropped;
     63     @GuardedBy("mLock")
     64     private int mCapacity;
     65 
     66     public IpConnectivityMetrics(Context ctx) {
     67         super(ctx);
     68         initBuffer();
     69     }
     70 
     71     @Override
     72     public void onStart() {
     73         if (DBG) Log.d(TAG, "onStart");
     74     }
     75 
     76     @Override
     77     public void onBootPhase(int phase) {
     78         if (phase == SystemService.PHASE_SYSTEM_SERVICES_READY) {
     79             if (DBG) Log.d(TAG, "onBootPhase");
     80             mDnsListener = new DnsEventListenerService(getContext());
     81 
     82             publishBinderService(SERVICE_NAME, impl);
     83             publishBinderService(mDnsListener.SERVICE_NAME, mDnsListener);
     84         }
     85     }
     86 
     87     @VisibleForTesting
     88     public int bufferCapacity() {
     89         return DEFAULT_BUFFER_SIZE; // TODO: read from config
     90     }
     91 
     92     private void initBuffer() {
     93         synchronized (mLock) {
     94             mDropped = 0;
     95             mCapacity = bufferCapacity();
     96             mBuffer = new ArrayList<>(mCapacity);
     97         }
     98     }
     99 
    100     private int append(ConnectivityMetricsEvent event) {
    101         if (DBG) Log.d(TAG, "logEvent: " + event);
    102         synchronized (mLock) {
    103             final int left = mCapacity - mBuffer.size();
    104             if (event == null) {
    105                 return left;
    106             }
    107             if (left == 0) {
    108                 mDropped++;
    109                 return 0;
    110             }
    111             mBuffer.add(event);
    112             return left - 1;
    113         }
    114     }
    115 
    116     private String flushEncodedOutput() {
    117         final ArrayList<ConnectivityMetricsEvent> events;
    118         final int dropped;
    119         synchronized (mLock) {
    120             events = mBuffer;
    121             dropped = mDropped;
    122             initBuffer();
    123         }
    124 
    125         final byte[] data;
    126         try {
    127             data = IpConnectivityEventBuilder.serialize(dropped, events);
    128         } catch (IOException e) {
    129             Log.e(TAG, "could not serialize events", e);
    130             return "";
    131         }
    132 
    133         return Base64.encodeToString(data, Base64.DEFAULT);
    134     }
    135 
    136     /**
    137      * Clears the event buffer and prints its content as a protobuf serialized byte array
    138      * inside a base64 encoded string.
    139      */
    140     private void cmdFlush(FileDescriptor fd, PrintWriter pw, String[] args) {
    141         pw.print(flushEncodedOutput());
    142     }
    143 
    144     /**
    145      * Prints the content of the event buffer, either using the events ASCII representation
    146      * or using protobuf text format.
    147      */
    148     private void cmdList(FileDescriptor fd, PrintWriter pw, String[] args) {
    149         final ArrayList<ConnectivityMetricsEvent> events;
    150         synchronized (mLock) {
    151             events = new ArrayList(mBuffer);
    152         }
    153 
    154         if (args.length > 1 && args[1].equals("proto")) {
    155             for (IpConnectivityEvent ev : IpConnectivityEventBuilder.toProto(events)) {
    156                 pw.print(ev.toString());
    157             }
    158             return;
    159         }
    160 
    161         for (ConnectivityMetricsEvent ev : events) {
    162             pw.println(ev.toString());
    163         }
    164     }
    165 
    166     private void cmdStats(FileDescriptor fd, PrintWriter pw, String[] args) {
    167         synchronized (mLock) {
    168             pw.println("Buffered events: " + mBuffer.size());
    169             pw.println("Buffer capacity: " + mCapacity);
    170             pw.println("Dropped events: " + mDropped);
    171         }
    172         if (mDnsListener != null) {
    173             mDnsListener.dump(pw);
    174         }
    175     }
    176 
    177     private void cmdDefault(FileDescriptor fd, PrintWriter pw, String[] args) {
    178         if (args.length == 0) {
    179             pw.println("No command");
    180             return;
    181         }
    182         pw.println("Unknown command " + TextUtils.join(" ", args));
    183     }
    184 
    185     public final class Impl extends IIpConnectivityMetrics.Stub {
    186         static final String CMD_FLUSH   = "flush";
    187         static final String CMD_LIST    = "list";
    188         static final String CMD_STATS   = "stats";
    189         static final String CMD_DEFAULT = CMD_STATS;
    190 
    191         @Override
    192         public int logEvent(ConnectivityMetricsEvent event) {
    193             enforceConnectivityInternalPermission();
    194             return append(event);
    195         }
    196 
    197         @Override
    198         public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
    199             enforceDumpPermission();
    200             if (DBG) Log.d(TAG, "dumpsys " + TextUtils.join(" ", args));
    201             final String cmd = (args.length > 0) ? args[0] : CMD_DEFAULT;
    202             switch (cmd) {
    203                 case CMD_FLUSH:
    204                     cmdFlush(fd, pw, args);
    205                     return;
    206                 case CMD_LIST:
    207                     cmdList(fd, pw, args);
    208                     return;
    209                 case CMD_STATS:
    210                     cmdStats(fd, pw, args);
    211                     return;
    212                 default:
    213                     cmdDefault(fd, pw, args);
    214             }
    215         }
    216 
    217         private void enforceConnectivityInternalPermission() {
    218             enforcePermission(android.Manifest.permission.CONNECTIVITY_INTERNAL);
    219         }
    220 
    221         private void enforceDumpPermission() {
    222             enforcePermission(android.Manifest.permission.DUMP);
    223         }
    224 
    225         private void enforcePermission(String what) {
    226             getContext().enforceCallingOrSelfPermission(what, "IpConnectivityMetrics");
    227         }
    228     };
    229 }
    230