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A library jar that provides APIs for Applications written for the Google Android Platform.
/*
* 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.annotation.NonNull;
import android.content.Context;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import com.android.internal.annotations.VisibleForTesting;
import java.io.FileDescriptor;
import java.io.PrintWriter;
import java.util.LinkedHashMap;
import java.util.Map;
/**
* A NetworkFactory is an entity that creates NetworkAgent objects.
* The bearers register with ConnectivityService using {@link #register} and
* their factory will start receiving scored NetworkRequests. NetworkRequests
* can be filtered 3 ways: by NetworkCapabilities, by score and more complexly by
* overridden function. All of these can be dynamic - changing NetworkCapabilities
* or score forces re-evaluation of all current requests.
*
* If any requests pass the filter some overrideable functions will be called.
* If the bearer only cares about very simple start/stopNetwork callbacks, those
* functions can be overridden. If the bearer needs more interaction, it can
* override addNetworkRequest and removeNetworkRequest which will give it each
* request that passes their current filters.
* @hide
**/
// TODO(b/187083878): factor out common code between this and NetworkFactoryImpl
class NetworkFactoryLegacyImpl extends Handler
implements NetworkFactoryShim {
private static final boolean DBG = NetworkFactory.DBG;
private static final boolean VDBG = NetworkFactory.VDBG;
// TODO(b/187082970): Replace CMD_* with Handler.post(() -> { ... }) since all the CMDs do is to
// run the tasks asynchronously on the Handler thread.
/**
* Pass a network request to the bearer. If the bearer believes it can
* satisfy the request it should connect to the network and create a
* NetworkAgent. Once the NetworkAgent is fully functional it will
* register itself with ConnectivityService using registerNetworkAgent.
* If the bearer cannot immediately satisfy the request (no network,
* user disabled the radio, lower-scored network) it should remember
* any NetworkRequests it may be able to satisfy in the future. It may
* disregard any that it will never be able to service, for example
* those requiring a different bearer.
* msg.obj = NetworkRequest
* msg.arg1 = score - the score of the network currently satisfying this
* request. If this bearer knows in advance it cannot
* exceed this score it should not try to connect, holding the request
* for the future.
* Note that subsequent events may give a different (lower
* or higher) score for this request, transmitted to each
* NetworkFactory through additional CMD_REQUEST_NETWORK msgs
* with the same NetworkRequest but an updated score.
* Also, network conditions may change for this bearer
* allowing for a better score in the future.
* msg.arg2 = the ID of the NetworkProvider currently responsible for the
* NetworkAgent handling this request, or NetworkProvider.ID_NONE if none.
*/
public static final int CMD_REQUEST_NETWORK = 1;
/**
* Cancel a network request
* msg.obj = NetworkRequest
*/
public static final int CMD_CANCEL_REQUEST = 2;
/**
* Internally used to set our best-guess score.
* msg.arg1 = new score
*/
private static final int CMD_SET_SCORE = 3;
/**
* Internally used to set our current filter for coarse bandwidth changes with
* technology changes.
* msg.obj = new filter
*/
private static final int CMD_SET_FILTER = 4;
final Context mContext;
final NetworkFactory mParent;
private final Map mNetworkRequests =
new LinkedHashMap<>();
private int mScore;
NetworkCapabilities mCapabilityFilter;
NetworkProvider mProvider = null;
NetworkFactoryLegacyImpl(NetworkFactory parent, Looper looper, Context context,
NetworkCapabilities filter) {
super(looper);
mParent = parent;
mContext = context;
mCapabilityFilter = filter;
}
/* Registers this NetworkFactory with the system. May only be called once per factory. */
@Override public void register(final String logTag) {
if (mProvider != null) {
throw new IllegalStateException("A NetworkFactory must only be registered once");
}
if (DBG) mParent.log("Registering NetworkFactory");
mProvider = new NetworkProvider(mContext, NetworkFactoryLegacyImpl.this.getLooper(),
logTag) {
@Override
public void onNetworkRequested(@NonNull NetworkRequest request, int score,
int servingProviderId) {
handleAddRequest(request, score, servingProviderId);
}
@Override
public void onNetworkRequestWithdrawn(@NonNull NetworkRequest request) {
handleRemoveRequest(request);
}
};
((ConnectivityManager) mContext.getSystemService(
Context.CONNECTIVITY_SERVICE)).registerNetworkProvider(mProvider);
}
/** Unregisters this NetworkFactory. After this call, the object can no longer be used. */
@Override public void terminate() {
if (mProvider == null) {
throw new IllegalStateException("This NetworkFactory was never registered");
}
if (DBG) mParent.log("Unregistering NetworkFactory");
((ConnectivityManager) mContext.getSystemService(Context.CONNECTIVITY_SERVICE))
.unregisterNetworkProvider(mProvider);
// Remove all pending messages, since this object cannot be reused. Any message currently
// being processed will continue to run.
removeCallbacksAndMessages(null);
}
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case CMD_REQUEST_NETWORK: {
handleAddRequest((NetworkRequest) msg.obj, msg.arg1, msg.arg2);
break;
}
case CMD_CANCEL_REQUEST: {
handleRemoveRequest((NetworkRequest) msg.obj);
break;
}
case CMD_SET_SCORE: {
handleSetScore(msg.arg1);
break;
}
case CMD_SET_FILTER: {
handleSetFilter((NetworkCapabilities) msg.obj);
break;
}
}
}
private static class NetworkRequestInfo {
public final NetworkRequest request;
public int score;
public boolean requested; // do we have a request outstanding, limited by score
public int providerId;
NetworkRequestInfo(NetworkRequest request, int score, int providerId) {
this.request = request;
this.score = score;
this.requested = false;
this.providerId = providerId;
}
@Override
public String toString() {
return "{" + request + ", score=" + score + ", requested=" + requested + "}";
}
}
/**
* Add a NetworkRequest that the bearer may want to attempt to satisfy.
* @see #CMD_REQUEST_NETWORK
*
* @param request the request to handle.
* @param score the score of the NetworkAgent currently satisfying this request.
* @param servingProviderId the ID of the NetworkProvider that created the NetworkAgent
* currently satisfying this request.
*/
@VisibleForTesting
protected void handleAddRequest(NetworkRequest request, int score, int servingProviderId) {
NetworkRequestInfo n = mNetworkRequests.get(request);
if (n == null) {
if (DBG) {
mParent.log("got request " + request + " with score " + score
+ " and providerId " + servingProviderId);
}
n = new NetworkRequestInfo(request, score, servingProviderId);
mNetworkRequests.put(n.request, n);
} else {
if (VDBG) {
mParent.log("new score " + score + " for existing request " + request
+ " and providerId " + servingProviderId);
}
n.score = score;
n.providerId = servingProviderId;
}
if (VDBG) mParent.log(" my score=" + mScore + ", my filter=" + mCapabilityFilter);
evalRequest(n);
}
private void handleRemoveRequest(NetworkRequest request) {
NetworkRequestInfo n = mNetworkRequests.get(request);
if (n != null) {
mNetworkRequests.remove(request);
if (n.requested) mParent.releaseNetworkFor(n.request);
}
}
private void handleSetScore(int score) {
mScore = score;
evalRequests();
}
private void handleSetFilter(NetworkCapabilities netCap) {
mCapabilityFilter = netCap;
evalRequests();
}
/**
* Overridable function to provide complex filtering.
* Called for every request every time a new NetworkRequest is seen
* and whenever the filterScore or filterNetworkCapabilities change.
*
* acceptRequest can be overridden to provide complex filter behavior
* for the incoming requests
*
* For output, this class will call {@link NetworkFactory#needNetworkFor} and
* {@link NetworkFactory#releaseNetworkFor} for every request that passes the filters.
* If you don't need to see every request, you can leave the base
* implementations of those two functions and instead override
* {@link NetworkFactory#startNetwork} and {@link NetworkFactory#stopNetwork}.
*
* If you want to see every score fluctuation on every request, set
* your score filter to a very high number and watch {@link NetworkFactory#needNetworkFor}.
*
* @return {@code true} to accept the request.
*/
public boolean acceptRequest(NetworkRequest request) {
return mParent.acceptRequest(request);
}
private void evalRequest(NetworkRequestInfo n) {
if (VDBG) {
mParent.log("evalRequest");
mParent.log(" n.requests = " + n.requested);
mParent.log(" n.score = " + n.score);
mParent.log(" mScore = " + mScore);
mParent.log(" request.providerId = " + n.providerId);
mParent.log(" mProvider.id = " + mProvider.getProviderId());
}
if (shouldNeedNetworkFor(n)) {
if (VDBG) mParent.log(" needNetworkFor");
mParent.needNetworkFor(n.request);
n.requested = true;
} else if (shouldReleaseNetworkFor(n)) {
if (VDBG) mParent.log(" releaseNetworkFor");
mParent.releaseNetworkFor(n.request);
n.requested = false;
} else {
if (VDBG) mParent.log(" done");
}
}
private boolean shouldNeedNetworkFor(NetworkRequestInfo n) {
// If this request is already tracked, it doesn't qualify for need
return !n.requested
// If the score of this request is higher or equal to that of this factory and some
// other factory is responsible for it, then this factory should not track the request
// because it has no hope of satisfying it.
&& (n.score < mScore || n.providerId == mProvider.getProviderId())
// If this factory can't satisfy the capability needs of this request, then it
// should not be tracked.
&& n.request.canBeSatisfiedBy(mCapabilityFilter)
// Finally if the concrete implementation of the factory rejects the request, then
// don't track it.
&& acceptRequest(n.request);
}
private boolean shouldReleaseNetworkFor(NetworkRequestInfo n) {
// Don't release a request that's not tracked.
return n.requested
// The request should be released if it can't be satisfied by this factory. That
// means either of the following conditions are met :
// - Its score is too high to be satisfied by this factory and it's not already
// assigned to the factory
// - This factory can't satisfy the capability needs of the request
// - The concrete implementation of the factory rejects the request
&& ((n.score > mScore && n.providerId != mProvider.getProviderId())
|| !n.request.canBeSatisfiedBy(mCapabilityFilter)
|| !acceptRequest(n.request));
}
private void evalRequests() {
for (NetworkRequestInfo n : mNetworkRequests.values()) {
evalRequest(n);
}
}
/**
* Post a command, on this NetworkFactory Handler, to re-evaluate all
* outstanding requests. Can be called from a factory implementation.
*/
@Override public void reevaluateAllRequests() {
post(this::evalRequests);
}
/**
* Can be called by a factory to release a request as unfulfillable: the request will be
* removed, and the caller will get a
* {@link ConnectivityManager.NetworkCallback#onUnavailable()} callback after this function
* returns.
*
* Note: this should only be called by factory which KNOWS that it is the ONLY factory which
* is able to fulfill this request!
*/
@Override public void releaseRequestAsUnfulfillableByAnyFactory(NetworkRequest r) {
post(() -> {
if (DBG) mParent.log("releaseRequestAsUnfulfillableByAnyFactory: " + r);
final NetworkProvider provider = mProvider;
if (provider == null) {
mParent.log("Ignoring attempt to release unregistered request as unfulfillable");
return;
}
provider.declareNetworkRequestUnfulfillable(r);
});
}
@Override public void setScoreFilter(int score) {
sendMessage(obtainMessage(CMD_SET_SCORE, score, 0));
}
@Override public void setScoreFilter(@NonNull final NetworkScore score) {
setScoreFilter(score.getLegacyInt());
}
@Override public void setCapabilityFilter(NetworkCapabilities netCap) {
sendMessage(obtainMessage(CMD_SET_FILTER, new NetworkCapabilities(netCap)));
}
@Override public int getRequestCount() {
return mNetworkRequests.size();
}
/* TODO: delete when all callers have migrated to NetworkProvider IDs. */
@Override public int getSerialNumber() {
return mProvider.getProviderId();
}
@Override public NetworkProvider getProvider() {
return mProvider;
}
@Override public void dump(FileDescriptor fd, PrintWriter writer, String[] args) {
writer.println(toString());
for (NetworkRequestInfo n : mNetworkRequests.values()) {
writer.println(" " + n);
}
}
@Override public String toString() {
return "providerId="
+ mProvider.getProviderId() + ", ScoreFilter="
+ mScore + ", Filter=" + mCapabilityFilter + ", requests="
+ mNetworkRequests.size();
}
}
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