1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
|
/*
* 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.wifi;
import android.os.Binder;
import android.os.IBinder;
import android.os.RemoteException;
import android.util.Slog;
import android.util.StatsLog;
import com.android.internal.app.IBatteryStats;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
/**
* WifiMulticastLockManager tracks holders of multicast locks and
* triggers enabling and disabling of filtering.
*
* @hide
*/
public class WifiMulticastLockManager {
private static final String TAG = "WifiMulticastLockManager";
private final List<Multicaster> mMulticasters = new ArrayList<>();
private int mMulticastEnabled = 0;
private int mMulticastDisabled = 0;
private boolean mVerboseLoggingEnabled = false;
private final IBatteryStats mBatteryStats;
private final FilterController mFilterController;
/** Delegate for handling state change events for multicast filtering. */
public interface FilterController {
/** Called when multicast filtering should be enabled */
void startFilteringMulticastPackets();
/** Called when multicast filtering should be disabled */
void stopFilteringMulticastPackets();
}
public WifiMulticastLockManager(FilterController filterController, IBatteryStats batteryStats) {
mBatteryStats = batteryStats;
mFilterController = filterController;
}
private class Multicaster implements IBinder.DeathRecipient {
String mTag;
int mUid;
IBinder mBinder;
Multicaster(String tag, IBinder binder) {
mTag = tag;
mUid = Binder.getCallingUid();
mBinder = binder;
try {
mBinder.linkToDeath(this, 0);
} catch (RemoteException e) {
binderDied();
}
}
@Override
public void binderDied() {
Slog.e(TAG, "Multicaster binderDied");
synchronized (mMulticasters) {
int i = mMulticasters.indexOf(this);
if (i != -1) {
removeMulticasterLocked(i, mUid, mTag);
}
}
}
void unlinkDeathRecipient() {
mBinder.unlinkToDeath(this, 0);
}
public int getUid() {
return mUid;
}
public String getTag() {
return mTag;
}
public String toString() {
return "Multicaster{" + mTag + " uid=" + mUid + "}";
}
}
protected void dump(PrintWriter pw) {
pw.println("mMulticastEnabled " + mMulticastEnabled);
pw.println("mMulticastDisabled " + mMulticastDisabled);
pw.println("Multicast Locks held:");
for (Multicaster l : mMulticasters) {
pw.print(" ");
pw.println(l);
}
}
protected void enableVerboseLogging(int verbose) {
if (verbose > 0) {
mVerboseLoggingEnabled = true;
} else {
mVerboseLoggingEnabled = false;
}
}
/** Start filtering if no multicasters exist. */
public void initializeFiltering() {
synchronized (mMulticasters) {
// if anybody had requested filters be off, leave off
if (mMulticasters.size() != 0) {
return;
} else {
mFilterController.startFilteringMulticastPackets();
}
}
}
/**
* Acquire a multicast lock.
* @param binder a binder used to ensure caller is still alive
* @param tag string name of the caller.
*/
public void acquireLock(IBinder binder, String tag) {
synchronized (mMulticasters) {
mMulticastEnabled++;
mMulticasters.add(new Multicaster(tag, binder));
// Note that we could call stopFilteringMulticastPackets only when
// our new size == 1 (first call), but this function won't
// be called often and by making the stopPacket call each
// time we're less fragile and self-healing.
mFilterController.stopFilteringMulticastPackets();
}
int uid = Binder.getCallingUid();
final long ident = Binder.clearCallingIdentity();
try {
mBatteryStats.noteWifiMulticastEnabled(uid);
StatsLog.write_non_chained(
StatsLog.WIFI_MULTICAST_LOCK_STATE_CHANGED, uid, null,
StatsLog.WIFI_MULTICAST_LOCK_STATE_CHANGED__STATE__ON, tag);
} catch (RemoteException e) {
} finally {
Binder.restoreCallingIdentity(ident);
}
}
/** Releases a multicast lock */
public void releaseLock(String tag) {
int uid = Binder.getCallingUid();
synchronized (mMulticasters) {
mMulticastDisabled++;
int size = mMulticasters.size();
for (int i = size - 1; i >= 0; i--) {
Multicaster m = mMulticasters.get(i);
if ((m != null) && (m.getUid() == uid) && (m.getTag().equals(tag))) {
removeMulticasterLocked(i, uid, tag);
break;
}
}
}
}
private void removeMulticasterLocked(int i, int uid, String tag) {
Multicaster removed = mMulticasters.remove(i);
if (removed != null) {
removed.unlinkDeathRecipient();
}
if (mMulticasters.size() == 0) {
mFilterController.startFilteringMulticastPackets();
}
final long ident = Binder.clearCallingIdentity();
try {
mBatteryStats.noteWifiMulticastDisabled(uid);
StatsLog.write_non_chained(
StatsLog.WIFI_MULTICAST_LOCK_STATE_CHANGED, uid, null,
StatsLog.WIFI_MULTICAST_LOCK_STATE_CHANGED__STATE__OFF, tag);
} catch (RemoteException e) {
} finally {
Binder.restoreCallingIdentity(ident);
}
}
/** Returns whether multicast should be allowed (filterning disabled). */
public boolean isMulticastEnabled() {
synchronized (mMulticasters) {
return (mMulticasters.size() > 0);
}
}
}
|
