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Merge "[NS04] Introduce Network Offers and their callbacks"

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This commit is contained in:
Remi NGUYEN VAN
2021-05-13 15:11:45 +00:00
committed by Gerrit Code Review
parent e562d167a5 823f81c36e
commit 393e7b3d6a
4 changed files with 272 additions and 1 deletions
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53
framework/src/android/net/ConnectivityManager.java
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@@ -3337,7 +3337,60 @@ public class ConnectivityManager {
provider.setProviderId(NetworkProvider.ID_NONE);
}
/**
* Register or update a network offer with ConnectivityService.
*
* ConnectivityService keeps track of offers made by the various providers and matches
* them to networking requests made by apps or the system. The provider supplies a score
* and the capabilities of the network it might be able to bring up ; these act as filters
* used by ConnectivityService to only send those requests that can be fulfilled by the
* provider.
*
* The provider is under no obligation to be able to bring up the network it offers at any
* given time. Instead, this mechanism is meant to limit requests received by providers
* to those they actually have a chance to fulfill, as providers don't have a way to compare
* the quality of the network satisfying a given request to their own offer.
*
* An offer can be updated by calling this again with the same callback object. This is
* similar to calling unofferNetwork and offerNetwork again, but will only update the
* provider with the changes caused by the changes in the offer.
*
* @param provider The provider making this offer.
* @param score The prospective score of the network.
* @param caps The prospective capabilities of the network.
* @param callback The callback to call when this offer is needed or unneeded.
* @hide
*/
@RequiresPermission(anyOf = {
NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK,
android.Manifest.permission.NETWORK_FACTORY})
public void offerNetwork(@NonNull final NetworkProvider provider,
@NonNull final NetworkScore score, @NonNull final NetworkCapabilities caps,
@NonNull final INetworkOfferCallback callback) {
try {
mService.offerNetwork(Objects.requireNonNull(provider.getMessenger(), "null messenger"),
Objects.requireNonNull(score, "null score"),
Objects.requireNonNull(caps, "null caps"),
Objects.requireNonNull(callback, "null callback"));
} catch (RemoteException e) {
throw e.rethrowFromSystemServer();
}
}
/**
* Withdraw a network offer made with {@link #offerNetwork}.
*
* @param callback The callback passed at registration time. This must be the same object
* that was passed to {@link #offerNetwork}
* @hide
*/
public void unofferNetwork(@NonNull final INetworkOfferCallback callback) {
try {
mService.unofferNetwork(Objects.requireNonNull(callback));
} catch (RemoteException e) {
throw e.rethrowFromSystemServer();
}
}
/** @hide exposed via the NetworkProvider class. */
@RequiresPermission(anyOf = {
NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK,

5
framework/src/android/net/IConnectivityManager.aidl
View File

@@ -23,6 +23,7 @@ import android.net.IConnectivityDiagnosticsCallback;
import android.net.INetworkAgent;
import android.net.IOnCompleteListener;
import android.net.INetworkActivityListener;
import android.net.INetworkOfferCallback;
import android.net.IQosCallback;
import android.net.ISocketKeepaliveCallback;
import android.net.LinkProperties;
@@ -221,4 +222,8 @@ interface IConnectivityManager
in IOnCompleteListener listener);
int getRestrictBackgroundStatusByCaller();
void offerNetwork(in Messenger messenger, in NetworkScore score,
in NetworkCapabilities caps, in INetworkOfferCallback callback);
void unofferNetwork(in INetworkOfferCallback callback);
}

62
framework/src/android/net/INetworkOfferCallback.aidl Normal file
View File

@@ -0,0 +1,62 @@
/*
* Copyright (C) 2021 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 android.net;
import android.net.NetworkRequest;
/**
* A callback registered with connectivity by network providers together with
* a NetworkOffer.
*
* When the offer is needed to satisfy some application or system component,
* connectivity will call onOfferNeeded on this callback. When this happens,
* the provider should try and bring up the network.
*
* When the offer is no longer needed, for example because the application has
* withdrawn the request or if the request is being satisfied by a network
* that this offer will never be able to beat, connectivity calls
* onOfferUnneeded. When this happens, the provider should stop trying to
* bring up the network, or tear it down if it has already been brought up.
*
* When NetworkProvider#offerNetwork is called, the provider can expect to
* immediately receive all requests that can be fulfilled by that offer and
* are not already satisfied by a better network. It is possible no such
* request is currently outstanding, because no requests have been made that
* can be satisfied by this offer, or because all such requests are already
* satisfied by a better network.
* onOfferNeeded can be called at any time after registration and until the
* offer is withdrawn with NetworkProvider#unofferNetwork is called. This
* typically happens when a new network request is filed by an application,
* or when the network satisfying a request disconnects and this offer now
* stands a chance to be the best network for it.
*
* @hide
*/
oneway interface INetworkOfferCallback {
/**
* Informs the registrant that the offer is needed to fulfill this request.
* @param networkRequest the request to satisfy
* @param providerId the ID of the provider currently satisfying
* this request, or NetworkProvider.ID_NONE if none.
*/
void onOfferNeeded(in NetworkRequest networkRequest, int providerId);
/**
* Informs the registrant that the offer is no longer needed to fulfill this request.
*/
void onOfferUnneeded(in NetworkRequest networkRequest);
}

153
framework/src/android/net/NetworkProvider.java
View File

@@ -28,6 +28,11 @@ import android.os.Message;
import android.os.Messenger;
import android.util.Log;
import com.android.internal.annotations.GuardedBy;
import java.util.ArrayList;
import java.util.concurrent.Executor;
/**
* Base class for network providers such as telephony or Wi-Fi. NetworkProviders connect the device
* to networks and makes them available to the core network stack by creating
@@ -78,7 +83,9 @@ public class NetworkProvider {
*/
@SystemApi
public NetworkProvider(@NonNull Context context, @NonNull Looper looper, @NonNull String name) {
Handler handler = new Handler(looper) {
// TODO (b/174636568) : this class should be able to cache an instance of
// ConnectivityManager so it doesn't have to fetch it again every time.
final Handler handler = new Handler(looper) {
@Override
public void handleMessage(Message m) {
switch (m.what) {
@@ -159,4 +166,148 @@ public class NetworkProvider {
public void declareNetworkRequestUnfulfillable(@NonNull NetworkRequest request) {
ConnectivityManager.from(mContext).declareNetworkRequestUnfulfillable(request);
}
/** @hide */
// TODO : make @SystemApi when the impl is complete
public interface NetworkOfferCallback {
/** Called by the system when this offer is needed to satisfy some networking request. */
void onOfferNeeded(@NonNull NetworkRequest request, int providerId);
/** Called by the system when this offer is no longer needed. */
void onOfferUnneeded(@NonNull NetworkRequest request);
}
private class NetworkOfferCallbackProxy extends INetworkOfferCallback.Stub {
@NonNull public final NetworkOfferCallback callback;
@NonNull private final Executor mExecutor;
NetworkOfferCallbackProxy(@NonNull final NetworkOfferCallback callback,
@NonNull final Executor executor) {
this.callback = callback;
this.mExecutor = executor;
}
@Override
public void onOfferNeeded(final @NonNull NetworkRequest request,
final int providerId) {
mExecutor.execute(() -> callback.onOfferNeeded(request, providerId));
}
@Override
public void onOfferUnneeded(final @NonNull NetworkRequest request) {
mExecutor.execute(() -> callback.onOfferUnneeded(request));
}
}
@GuardedBy("mProxies")
@NonNull private final ArrayList<NetworkOfferCallbackProxy> mProxies = new ArrayList<>();
// Returns the proxy associated with this callback, or null if none.
@Nullable
private NetworkOfferCallbackProxy findProxyForCallback(@NonNull final NetworkOfferCallback cb) {
synchronized (mProxies) {
for (final NetworkOfferCallbackProxy p : mProxies) {
if (p.callback == cb) return p;
}
}
return null;
}
/**
* Register or update an offer for network with the passed caps and score.
*
* A NetworkProvider's job is to provide networks. This function is how a provider tells the
* connectivity stack what kind of network it may provide. The score and caps arguments act
* as filters that the connectivity stack uses to tell when the offer is necessary. When an
* offer might be advantageous over existing networks, the provider will receive a call to
* the associated callback's {@link NetworkOfferCallback#onOfferNeeded} method. The provider
* should then try to bring up this network. When an offer is no longer needed, the stack
* will inform the provider by calling {@link NetworkOfferCallback#onOfferUnneeded}. The
* provider should stop trying to bring up such a network, or disconnect it if it already has
* one.
*
* The stack determines what offers are needed according to what networks are currently
* available to the system, and what networking requests are made by applications. If an
* offer looks like it could be a better choice than any existing network for any particular
* request, that's when the stack decides the offer is needed. If the current networking
* requests are all satisfied by networks that this offer can't possibly be a better match
* for, that's when the offer is unneeded. An offer starts off as unneeded ; the provider
* should not try to bring up the network until {@link NetworkOfferCallback#onOfferNeeded}
* is called.
*
* Note that the offers are non-binding to the providers, in particular because providers
* often don't know if they will be able to bring up such a network at any given time. For
* example, no wireless network may be in range when the offer is needed. This is fine and
* expected ; the provider should simply continue to try to bring up the network and do so
* if/when it becomes possible. In the mean time, the stack will continue to satisfy requests
* with the best network currently available, or if none, keep the apps informed that no
* network can currently satisfy this request. When/if the provider can bring up the network,
* the connectivity stack will match it against requests, and inform interested apps of the
* availability of this network. This may, in turn, render the offer of some other provider
* unneeded if all requests it used to satisfy are now better served by this network.
*
* A network can become unneeded for a reason like the above : whether the provider managed
* to bring up the offered network after it became needed or not, some other provider may
* bring up a better network than this one, making this offer unneeded. A network may also
* become unneeded if the application making the request withdrew it (for example, after it
* is done transferring data, or if the user canceled an operation).
*
* The capabilities and score act as filters as to what requests the provider will see.
* They are not promises, but for best performance, the providers should strive to put
* as much known information as possible in the offer. For capabilities in particular, it
* should put all NetworkAgent-managed capabilities a network may have, even if it doesn't
* have them at first. This applies to INTERNET, for example ; if a provider thinks the
* network it can bring up for this offer may offer Internet access it should include the
* INTERNET bit. It's fine if the brought up network ends up not actually having INTERNET.
*
* TODO : in the future, to avoid possible infinite loops, there should be constraints on
* what can be put in capabilities of networks brought up for an offer. If a provider might
* bring up a network with or without INTERNET, then it should file two offers : this will
* let it know precisely what networks are needed, so it can avoid bringing up networks that
* won't actually satisfy requests and remove the risk for bring-up-bring-down loops.
*
* @hide
*/
// TODO : make @SystemApi when the impl is complete
@RequiresPermission(android.Manifest.permission.NETWORK_FACTORY)
public void offerNetwork(@NonNull final NetworkScore score,
@NonNull final NetworkCapabilities caps, @NonNull final Executor executor,
@NonNull final NetworkOfferCallback callback) {
NetworkOfferCallbackProxy proxy = null;
synchronized (mProxies) {
for (final NetworkOfferCallbackProxy existingProxy : mProxies) {
if (existingProxy.callback == callback) {
proxy = existingProxy;
break;
}
}
if (null == proxy) {
proxy = new NetworkOfferCallbackProxy(callback, executor);
mProxies.add(proxy);
}
}
mContext.getSystemService(ConnectivityManager.class).offerNetwork(this, score, caps, proxy);
}
/**
* Withdraw a network offer previously made to the networking stack.
*
* If a provider can no longer provide a network they offered, it should call this method.
* An example of usage could be if the hardware necessary to bring up the network was turned
* off in UI by the user. Note that because offers are never binding, the provider might
* alternatively decide not to withdraw this offer and simply refuse to bring up the network
* even when it's needed. However, withdrawing the request is slightly more resource-efficient
* because the networking stack won't have to compare this offer to exiting networks to see
* if it could beat any of them, and may be advantageous to the provider's implementation that
* can rely on no longer receiving callbacks for a network that they can't bring up anyways.
*
* @hide
*/
// TODO : make @SystemApi when the impl is complete
@RequiresPermission(android.Manifest.permission.NETWORK_FACTORY)
public void unofferNetwork(final @NonNull NetworkOfferCallback callback) {
final NetworkOfferCallbackProxy proxy = findProxyForCallback(callback);
if (null == proxy) return;
mProxies.remove(proxy);
mContext.getSystemService(ConnectivityManager.class).unofferNetwork(proxy);
}
}