Add a background NetworkRequest type for mobile data always on.
Like a normal (foreground) request, a background request is only
satisfied by one network and will keep that network up. Unlike a
foreground request, when a network only has background requests,
it will linger, and after lingering is complete, it will become
a background network.
Future CLs will cause the system to treat background networks
differently, e.g., by requiring different permissions.
Bug: 23113288
Change-Id: I40f735269dad1042eb04fea15e64584fc903ccb3
diff --git a/core/java/android/net/NetworkRequest.java b/core/java/android/net/NetworkRequest.java
index 4501f7b..ae72470 100644
--- a/core/java/android/net/NetworkRequest.java
+++ b/core/java/android/net/NetworkRequest.java
@@ -49,7 +49,7 @@
public final int legacyType;
/**
- * A NetworkRequest as used by the system can be one of three types:
+ * A NetworkRequest as used by the system can be one of the following types:
*
* - LISTEN, for which the framework will issue callbacks about any
* and all networks that match the specified NetworkCapabilities,
@@ -64,7 +64,20 @@
* current network (if any) that matches the capabilities of the
* default Internet request (mDefaultRequest), but which cannot cause
* the framework to either create or retain the existence of any
- * specific network.
+ * specific network. Note that from the point of view of the request
+ * matching code, TRACK_DEFAULT is identical to REQUEST: its special
+ * behaviour is not due to different semantics, but to the fact that
+ * the system will only ever create a TRACK_DEFAULT with capabilities
+ * that are identical to the default request's capabilities, thus
+ * causing it to share fate in every way with the default request.
+ *
+ * - BACKGROUND_REQUEST, like REQUEST but does not cause any networks
+ * to retain the NET_CAPABILITY_FOREGROUND capability. A network with
+ * no foreground requests is in the background. A network that has
+ * one or more background requests and loses its last foreground
+ * request to a higher-scoring network will not go into the
+ * background immediately, but will linger and go into the background
+ * after the linger timeout.
*
* - The value NONE is used only by applications. When an application
* creates a NetworkRequest, it does not have a type; the type is set
@@ -77,7 +90,8 @@
NONE,
LISTEN,
TRACK_DEFAULT,
- REQUEST
+ REQUEST,
+ BACKGROUND_REQUEST,
};
/**
@@ -140,7 +154,7 @@
* Add the given capability requirement to this builder. These represent
* the requested network's required capabilities. Note that when searching
* for a network to satisfy a request, all capabilities requested must be
- * satisfied. See {@link NetworkCapabilities} for {@code NET_CAPABILITIY_*}
+ * satisfied. See {@link NetworkCapabilities} for {@code NET_CAPABILITY_*}
* definitions.
*
* @param capability The {@code NetworkCapabilities.NET_CAPABILITY_*} to add.
@@ -284,7 +298,7 @@
};
/**
- * Returns true iff. the contained NetworkRequest is of type LISTEN.
+ * Returns true iff. this NetworkRequest is of type LISTEN.
*
* @hide
*/
@@ -298,8 +312,9 @@
* - should be associated with at most one satisfying network
* at a time;
*
- * - should cause a network to be kept up if it is the best network
- * which can satisfy the NetworkRequest.
+ * - should cause a network to be kept up, but not necessarily in
+ * the foreground, if it is the best network which can satisfy the
+ * NetworkRequest.
*
* For full detail of how isRequest() is used for pairing Networks with
* NetworkRequests read rematchNetworkAndRequests().
@@ -307,9 +322,36 @@
* @hide
*/
public boolean isRequest() {
+ return isForegroundRequest() || isBackgroundRequest();
+ }
+
+ /**
+ * Returns true iff. the contained NetworkRequest is one that:
+ *
+ * - should be associated with at most one satisfying network
+ * at a time;
+ *
+ * - should cause a network to be kept up and in the foreground if
+ * it is the best network which can satisfy the NetworkRequest.
+ *
+ * For full detail of how isRequest() is used for pairing Networks with
+ * NetworkRequests read rematchNetworkAndRequests().
+ *
+ * @hide
+ */
+ public boolean isForegroundRequest() {
return type == Type.TRACK_DEFAULT || type == Type.REQUEST;
}
+ /**
+ * Returns true iff. this NetworkRequest is of type BACKGROUND_REQUEST.
+ *
+ * @hide
+ */
+ public boolean isBackgroundRequest() {
+ return type == Type.BACKGROUND_REQUEST;
+ }
+
public String toString() {
return "NetworkRequest [ " + type + " id=" + requestId +
(legacyType != ConnectivityManager.TYPE_NONE ? ", legacyType=" + legacyType : "") +
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 0c23d1a..eddc4f4 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -262,6 +262,11 @@
DONT_REAP
};
+ private enum UnneededFor {
+ LINGER, // Determine whether this network is unneeded and should be lingered.
+ TEARDOWN, // Determine whether this network is unneeded and should be torn down.
+ }
+
/**
* used internally to change our mobile data enabled flag
*/
@@ -691,13 +696,13 @@
if (DBG) log("ConnectivityService starting up");
mMetricsLog = logger;
- mDefaultRequest = createInternetRequestForTransport(-1);
+ mDefaultRequest = createInternetRequestForTransport(-1, NetworkRequest.Type.REQUEST);
NetworkRequestInfo defaultNRI = new NetworkRequestInfo(null, mDefaultRequest, new Binder());
mNetworkRequests.put(mDefaultRequest, defaultNRI);
mNetworkRequestInfoLogs.log("REGISTER " + defaultNRI);
mDefaultMobileDataRequest = createInternetRequestForTransport(
- NetworkCapabilities.TRANSPORT_CELLULAR);
+ NetworkCapabilities.TRANSPORT_CELLULAR, NetworkRequest.Type.BACKGROUND_REQUEST);
mHandlerThread = createHandlerThread();
mHandlerThread.start();
@@ -848,15 +853,15 @@
mLingerMonitor = new LingerMonitor(mContext, mNotifier, dailyLimit, rateLimit);
}
- private NetworkRequest createInternetRequestForTransport(int transportType) {
+ private NetworkRequest createInternetRequestForTransport(
+ int transportType, NetworkRequest.Type type) {
NetworkCapabilities netCap = new NetworkCapabilities();
netCap.addCapability(NET_CAPABILITY_INTERNET);
netCap.addCapability(NET_CAPABILITY_NOT_RESTRICTED);
if (transportType > -1) {
netCap.addTransportType(transportType);
}
- return new NetworkRequest(netCap, TYPE_NONE, nextNetworkRequestId(),
- NetworkRequest.Type.REQUEST);
+ return new NetworkRequest(netCap, TYPE_NONE, nextNetworkRequestId(), type);
}
// Used only for testing.
@@ -1970,8 +1975,12 @@
for (NetworkAgentInfo nai : mNetworkAgentInfos.values()) {
pw.println(nai.toString());
pw.increaseIndent();
- pw.println(String.format("Requests: %d request/%d total",
- nai.numRequestNetworkRequests(), nai.numNetworkRequests()));
+ pw.println(String.format(
+ "Requests: REQUEST:%d LISTEN:%d BACKGROUND_REQUEST:%d total:%d",
+ nai.numForegroundNetworkRequests(),
+ nai.numNetworkRequests() - nai.numRequestNetworkRequests(),
+ nai.numBackgroundNetworkRequests(),
+ nai.numNetworkRequests()));
pw.increaseIndent();
for (int i = 0; i < nai.numNetworkRequests(); i++) {
pw.println(nai.requestAt(i).toString());
@@ -2292,15 +2301,13 @@
// 3. If this network is unneeded (which implies it is not lingering), and there is at least
// one lingered request, start lingering.
nai.updateLingerTimer();
- if (nai.isLingering() && nai.numRequestNetworkRequests() > 0) {
+ if (nai.isLingering() && nai.numForegroundNetworkRequests() > 0) {
if (DBG) log("Unlingering " + nai.name());
nai.unlinger();
logNetworkEvent(nai, NetworkEvent.NETWORK_UNLINGER);
- } else if (unneeded(nai) && nai.getLingerExpiry() > 0) { // unneeded() calls isLingering()
+ } else if (unneeded(nai, UnneededFor.LINGER) && nai.getLingerExpiry() > 0) {
int lingerTime = (int) (nai.getLingerExpiry() - now);
- if (DBG) {
- Log.d(TAG, "Lingering " + nai.name() + " for " + lingerTime + "ms");
- }
+ if (DBG) log("Lingering " + nai.name() + " for " + lingerTime + "ms");
nai.linger();
logNetworkEvent(nai, NetworkEvent.NETWORK_LINGER);
notifyNetworkCallbacks(nai, ConnectivityManager.CALLBACK_LOSING, lingerTime);
@@ -2479,15 +2486,37 @@
}
}
- // Is nai unneeded by all NetworkRequests (and should be disconnected)?
- // This is whether it is satisfying any NetworkRequests or were it to become validated,
- // would it have a chance of satisfying any NetworkRequests.
- private boolean unneeded(NetworkAgentInfo nai) {
- if (!nai.everConnected || nai.isVPN() ||
- nai.isLingering() || nai.numRequestNetworkRequests() > 0) {
+ // Determines whether the network is the best (or could become the best, if it validated), for
+ // none of a particular type of NetworkRequests. The type of NetworkRequests considered depends
+ // on the value of reason:
+ //
+ // - UnneededFor.TEARDOWN: non-listen NetworkRequests. If a network is unneeded for this reason,
+ // then it should be torn down.
+ // - UnneededFor.LINGER: foreground NetworkRequests. If a network is unneeded for this reason,
+ // then it should be lingered.
+ private boolean unneeded(NetworkAgentInfo nai, UnneededFor reason) {
+ final int numRequests;
+ switch (reason) {
+ case TEARDOWN:
+ numRequests = nai.numRequestNetworkRequests();
+ break;
+ case LINGER:
+ numRequests = nai.numForegroundNetworkRequests();
+ break;
+ default:
+ Slog.wtf(TAG, "Invalid reason. Cannot happen.");
+ return true;
+ }
+
+ if (!nai.everConnected || nai.isVPN() || nai.isLingering() || numRequests > 0) {
return false;
}
for (NetworkRequestInfo nri : mNetworkRequests.values()) {
+ if (reason == UnneededFor.LINGER && nri.request.isBackgroundRequest()) {
+ // Background requests don't affect lingering.
+ continue;
+ }
+
// If this Network is already the highest scoring Network for a request, or if
// there is hope for it to become one if it validated, then it is needed.
if (nri.request.isRequest() && nai.satisfies(nri.request) &&
@@ -2583,7 +2612,7 @@
// If there are still lingered requests on this network, don't tear it down,
// but resume lingering instead.
updateLingerState(nai, SystemClock.elapsedRealtime());
- if (unneeded(nai)) {
+ if (unneeded(nai, UnneededFor.TEARDOWN)) {
if (DBG) log("no live requests for " + nai.name() + "; disconnecting");
teardownUnneededNetwork(nai);
} else {
@@ -4612,7 +4641,7 @@
// must be no other active linger timers, and we must stop lingering.
oldNetwork.clearLingerState();
- if (unneeded(oldNetwork)) {
+ if (unneeded(oldNetwork, UnneededFor.TEARDOWN)) {
teardownUnneededNetwork(oldNetwork);
}
}
@@ -4880,7 +4909,7 @@
}
if (reapUnvalidatedNetworks == ReapUnvalidatedNetworks.REAP) {
for (NetworkAgentInfo nai : mNetworkAgentInfos.values()) {
- if (unneeded(nai)) {
+ if (unneeded(nai, UnneededFor.TEARDOWN)) {
if (nai.getLingerExpiry() > 0) {
// This network has active linger timers and no requests, but is not
// lingering. Linger it.
diff --git a/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java b/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java
index b0330b9..7044e60 100644
--- a/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java
+++ b/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java
@@ -104,14 +104,16 @@
// -----------------------------------------------
// If a network has no chance of satisfying any requests (even if it were to become validated
// and enter state #5), ConnectivityService will disconnect the NetworkAgent's AsyncChannel.
-// If the network ever for any period of time had satisfied a NetworkRequest (i.e. had been
-// the highest scoring that satisfied the NetworkRequest's constraints), but is no longer the
-// highest scoring network for any NetworkRequest, then there will be a 30s pause before
-// ConnectivityService disconnects the NetworkAgent's AsyncChannel. During this pause the
-// network is considered "lingering". This pause exists to allow network communication to be
-// wrapped up rather than abruptly terminated. During this pause if the network begins satisfying
-// a NetworkRequest, ConnectivityService will cancel the future disconnection of the NetworkAgent's
-// AsyncChannel, and the network is no longer considered "lingering".
+//
+// If the network was satisfying a foreground NetworkRequest (i.e. had been the highest scoring that
+// satisfied the NetworkRequest's constraints), but is no longer the highest scoring network for any
+// foreground NetworkRequest, then there will be a 30s pause to allow network communication to be
+// wrapped up rather than abruptly terminated. During this pause the network is said to be
+// "lingering". During this pause if the network begins satisfying a foreground NetworkRequest,
+// ConnectivityService will cancel the future disconnection of the NetworkAgent's AsyncChannel, and
+// the network is no longer considered "lingering". After the linger timer expires, if the network
+// is satisfying one or more background NetworkRequests it is kept up in the background. If it is
+// not, ConnectivityService disconnects the NetworkAgent's AsyncChannel.
public class NetworkAgentInfo implements Comparable<NetworkAgentInfo> {
public NetworkInfo networkInfo;
// This Network object should always be used if possible, so as to encourage reuse of the
@@ -227,11 +229,13 @@
// The list of NetworkRequests being satisfied by this Network.
private final SparseArray<NetworkRequest> mNetworkRequests = new SparseArray<>();
- // The list of NetworkRequests that this Network previously satisfied with the highest
- // score. A non-empty list indicates that if this Network was validated it is lingered.
+
// How many of the satisfied requests are actual requests and not listens.
private int mNumRequestNetworkRequests = 0;
+ // How many of the satisfied requests are of type BACKGROUND_REQUEST.
+ private int mNumBackgroundNetworkRequests = 0;
+
public final Messenger messenger;
public final AsyncChannel asyncChannel;
@@ -265,6 +269,32 @@
//
// These functions must only called on ConnectivityService's main thread.
+ private static final boolean ADD = true;
+ private static final boolean REMOVE = false;
+
+ private void updateRequestCounts(boolean add, NetworkRequest request) {
+ int delta = add ? +1 : -1;
+ switch (request.type) {
+ case REQUEST:
+ case TRACK_DEFAULT:
+ mNumRequestNetworkRequests += delta;
+ break;
+
+ case BACKGROUND_REQUEST:
+ mNumRequestNetworkRequests += delta;
+ mNumBackgroundNetworkRequests += delta;
+ break;
+
+ case LISTEN:
+ break;
+
+ case NONE:
+ default:
+ Log.wtf(TAG, "Unhandled request type " + request.type);
+ break;
+ }
+ }
+
/**
* Add {@code networkRequest} to this network as it's satisfied by this network.
* @return true if {@code networkRequest} was added or false if {@code networkRequest} was
@@ -273,9 +303,15 @@
public boolean addRequest(NetworkRequest networkRequest) {
NetworkRequest existing = mNetworkRequests.get(networkRequest.requestId);
if (existing == networkRequest) return false;
- if (existing != null && existing.isRequest()) mNumRequestNetworkRequests--;
+ if (existing != null) {
+ // Should only happen if the requestId wraps. If that happens lots of other things will
+ // be broken as well.
+ Log.wtf(TAG, String.format("Duplicate requestId for %s and %s on %s",
+ networkRequest, existing, name()));
+ updateRequestCounts(REMOVE, existing);
+ }
mNetworkRequests.put(networkRequest.requestId, networkRequest);
- if (networkRequest.isRequest()) mNumRequestNetworkRequests++;
+ updateRequestCounts(ADD, networkRequest);
return true;
}
@@ -285,9 +321,9 @@
public void removeRequest(int requestId) {
NetworkRequest existing = mNetworkRequests.get(requestId);
if (existing == null) return;
+ updateRequestCounts(REMOVE, existing);
mNetworkRequests.remove(requestId);
if (existing.isRequest()) {
- mNumRequestNetworkRequests--;
unlingerRequest(existing);
}
}
@@ -316,12 +352,37 @@
}
/**
+ * Returns the number of requests currently satisfied by this network of type
+ * {@link android.net.NetworkRequest.Type.BACKGROUND_REQUEST}.
+ */
+ public int numBackgroundNetworkRequests() {
+ return mNumBackgroundNetworkRequests;
+ }
+
+ /**
+ * Returns the number of foreground requests currently satisfied by this network.
+ */
+ public int numForegroundNetworkRequests() {
+ return mNumRequestNetworkRequests - mNumBackgroundNetworkRequests;
+ }
+
+ /**
* Returns the number of requests of any type currently satisfied by this network.
*/
public int numNetworkRequests() {
return mNetworkRequests.size();
}
+ /**
+ * Returns whether the network is a background network. A network is a background network if it
+ * is satisfying no foreground requests and at least one background request. (If it did not have
+ * a background request, it would be a speculative network that is only being kept up because
+ * it might satisfy a request if it validated).
+ */
+ public boolean isBackgroundNetwork() {
+ return numForegroundNetworkRequests() == 0 && mNumBackgroundNetworkRequests > 0;
+ }
+
// Does this network satisfy request?
public boolean satisfies(NetworkRequest request) {
return created &&
