1 /*
2  * Copyright (C) 2021 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 
21 import com.android.internal.annotations.VisibleForTesting;
22 import com.android.server.ConnectivityService;
23 
24 /**
25  * Collection of constants for the connectivity module.
26  */
27 public final class ConnectivityFlags {
28     /**
29      * Minimum module version at which to avoid rematching all requests when a network request is
30      * registered, and rematch only the registered requests instead.
31      */
32     @VisibleForTesting
33     public static final String NO_REMATCH_ALL_REQUESTS_ON_REGISTER =
34             "no_rematch_all_requests_on_register";
35 
36     public static final String CARRIER_SERVICE_CHANGED_USE_CALLBACK =
37             "carrier_service_changed_use_callback_version";
38 
39     public static final String REQUEST_RESTRICTED_WIFI =
40             "request_restricted_wifi";
41 
42     public static final String INGRESS_TO_VPN_ADDRESS_FILTERING =
43             "ingress_to_vpn_address_filtering";
44 
45     public static final String BACKGROUND_FIREWALL_CHAIN = "background_firewall_chain";
46 
47     public static final String DELAY_DESTROY_SOCKETS = "delay_destroy_sockets";
48 
49     public static final String USE_DECLARED_METHODS_FOR_CALLBACKS =
50             "use_declared_methods_for_callbacks";
51 
52     private boolean mNoRematchAllRequestsOnRegister;
53 
54     /**
55      * Whether ConnectivityService should avoid avoid rematching all requests when a network
56      * request is registered, and rematch only the registered requests instead.
57      *
58      * This flag is disabled by default.
59      *
60      * IMPORTANT NOTE: This flag is false by default and will only be loaded in ConnectivityService
61      * systemReady. It is also not volatile for performance reasons, so for most threads it may
62      * only change to true after some time. This is fine for this particular flag because it only
63      * controls whether all requests or a subset of requests should be rematched, which is only
64      * a performance optimization, so its value does not need to be consistent over time; but most
65      * flags will not have these properties and should not use the same model.
66      *
67      * TODO: when adding other flags, consider the appropriate timing to load them, and necessary
68      * threading guarantees according to the semantics of the flags.
69      */
noRematchAllRequestsOnRegister()70     public boolean noRematchAllRequestsOnRegister() {
71         return mNoRematchAllRequestsOnRegister;
72     }
73 
74     /**
75      * Load flag values. Should only be called once, and can only be called once PackageManager is
76      * ready.
77      */
loadFlags(ConnectivityService.Dependencies deps, Context ctx)78     public void loadFlags(ConnectivityService.Dependencies deps, Context ctx) {
79         mNoRematchAllRequestsOnRegister = deps.isFeatureEnabled(
80                 ctx, NO_REMATCH_ALL_REQUESTS_ON_REGISTER);
81     }
82 }
83