| /* |
| * Copyright (C) 2017 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.connectivity.tethering; |
| |
| import static android.net.ConnectivityManager.TYPE_MOBILE_DUN; |
| import static android.net.ConnectivityManager.TYPE_MOBILE_HIPRI; |
| import static android.net.ConnectivityManager.TYPE_NONE; |
| import static android.net.ConnectivityManager.getNetworkTypeName; |
| import static android.net.NetworkCapabilities.NET_CAPABILITY_DUN; |
| import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_VPN; |
| import static android.net.NetworkCapabilities.TRANSPORT_CELLULAR; |
| |
| import android.content.Context; |
| import android.net.ConnectivityManager; |
| import android.net.ConnectivityManager.NetworkCallback; |
| import android.net.IpPrefix; |
| import android.net.LinkProperties; |
| import android.net.Network; |
| import android.net.NetworkCapabilities; |
| import android.net.NetworkRequest; |
| import android.net.NetworkState; |
| import android.net.util.PrefixUtils; |
| import android.net.util.SharedLog; |
| import android.os.Handler; |
| import android.os.Process; |
| import android.util.Log; |
| |
| import com.android.internal.annotations.VisibleForTesting; |
| import com.android.internal.util.StateMachine; |
| |
| import java.util.HashMap; |
| import java.util.HashSet; |
| import java.util.Set; |
| |
| |
| /** |
| * A class to centralize all the network and link properties information |
| * pertaining to the current and any potential upstream network. |
| * |
| * The owner of UNM gets it to register network callbacks by calling the |
| * following methods : |
| * Calling #startTrackDefaultNetwork() to track the system default network. |
| * Calling #startObserveAllNetworks() to observe all networks. Listening all |
| * networks is necessary while the expression of preferred upstreams remains |
| * a list of legacy connectivity types. In future, this can be revisited. |
| * Calling #registerMobileNetworkRequest() to bring up mobile DUN/HIPRI network. |
| * |
| * The methods and data members of this class are only to be accessed and |
| * modified from the tethering master state machine thread. Any other |
| * access semantics would necessitate the addition of locking. |
| * |
| * TODO: Move upstream selection logic here. |
| * |
| * All callback methods are run on the same thread as the specified target |
| * state machine. This class does not require locking when accessed from this |
| * thread. Access from other threads is not advised. |
| * |
| * @hide |
| */ |
| public class UpstreamNetworkMonitor { |
| private static final String TAG = UpstreamNetworkMonitor.class.getSimpleName(); |
| private static final boolean DBG = false; |
| private static final boolean VDBG = false; |
| |
| public static final int EVENT_ON_CAPABILITIES = 1; |
| public static final int EVENT_ON_LINKPROPERTIES = 2; |
| public static final int EVENT_ON_LOST = 3; |
| public static final int NOTIFY_LOCAL_PREFIXES = 10; |
| |
| private static final int CALLBACK_LISTEN_ALL = 1; |
| private static final int CALLBACK_DEFAULT_INTERNET = 2; |
| private static final int CALLBACK_MOBILE_REQUEST = 3; |
| |
| private final Context mContext; |
| private final SharedLog mLog; |
| private final StateMachine mTarget; |
| private final Handler mHandler; |
| private final int mWhat; |
| private final HashMap<Network, NetworkState> mNetworkMap = new HashMap<>(); |
| private HashSet<IpPrefix> mLocalPrefixes; |
| private ConnectivityManager mCM; |
| private EntitlementManager mEntitlementMgr; |
| private NetworkCallback mListenAllCallback; |
| private NetworkCallback mDefaultNetworkCallback; |
| private NetworkCallback mMobileNetworkCallback; |
| private boolean mDunRequired; |
| // Whether the current default upstream is mobile or not. |
| private boolean mIsDefaultCellularUpstream; |
| // The current system default network (not really used yet). |
| private Network mDefaultInternetNetwork; |
| // The current upstream network used for tethering. |
| private Network mTetheringUpstreamNetwork; |
| |
| public UpstreamNetworkMonitor(Context ctx, StateMachine tgt, SharedLog log, int what) { |
| mContext = ctx; |
| mTarget = tgt; |
| mHandler = mTarget.getHandler(); |
| mLog = log.forSubComponent(TAG); |
| mWhat = what; |
| mLocalPrefixes = new HashSet<>(); |
| mIsDefaultCellularUpstream = false; |
| } |
| |
| @VisibleForTesting |
| public UpstreamNetworkMonitor( |
| ConnectivityManager cm, StateMachine tgt, SharedLog log, int what) { |
| this((Context) null, tgt, log, what); |
| mCM = cm; |
| } |
| |
| /** |
| * Tracking the system default network. This method should be called when system is ready. |
| * |
| * @param defaultNetworkRequest should be the same as ConnectivityService default request |
| * @param entitle a EntitlementManager object to communicate between EntitlementManager and |
| * UpstreamNetworkMonitor |
| */ |
| public void startTrackDefaultNetwork(NetworkRequest defaultNetworkRequest, |
| EntitlementManager entitle) { |
| // This is not really a "request", just a way of tracking the system default network. |
| // It's guaranteed not to actually bring up any networks because it's the same request |
| // as the ConnectivityService default request, and thus shares fate with it. We can't |
| // use registerDefaultNetworkCallback because it will not track the system default |
| // network if there is a VPN that applies to our UID. |
| if (mDefaultNetworkCallback == null) { |
| final NetworkRequest trackDefaultRequest = new NetworkRequest(defaultNetworkRequest); |
| mDefaultNetworkCallback = new UpstreamNetworkCallback(CALLBACK_DEFAULT_INTERNET); |
| cm().requestNetwork(trackDefaultRequest, mDefaultNetworkCallback, mHandler); |
| } |
| if (mEntitlementMgr == null) { |
| mEntitlementMgr = entitle; |
| } |
| } |
| |
| public void startObserveAllNetworks() { |
| stop(); |
| |
| final NetworkRequest listenAllRequest = new NetworkRequest.Builder() |
| .clearCapabilities().build(); |
| mListenAllCallback = new UpstreamNetworkCallback(CALLBACK_LISTEN_ALL); |
| cm().registerNetworkCallback(listenAllRequest, mListenAllCallback, mHandler); |
| } |
| |
| public void stop() { |
| releaseMobileNetworkRequest(); |
| |
| releaseCallback(mListenAllCallback); |
| mListenAllCallback = null; |
| |
| mTetheringUpstreamNetwork = null; |
| mNetworkMap.clear(); |
| } |
| |
| public void updateMobileRequiresDun(boolean dunRequired) { |
| final boolean valueChanged = (mDunRequired != dunRequired); |
| mDunRequired = dunRequired; |
| if (valueChanged && mobileNetworkRequested()) { |
| releaseMobileNetworkRequest(); |
| registerMobileNetworkRequest(); |
| } |
| } |
| |
| public boolean mobileNetworkRequested() { |
| return (mMobileNetworkCallback != null); |
| } |
| |
| public void registerMobileNetworkRequest() { |
| if (!isCellularUpstreamPermitted()) { |
| mLog.i("registerMobileNetworkRequest() is not permitted"); |
| releaseMobileNetworkRequest(); |
| return; |
| } |
| if (mMobileNetworkCallback != null) { |
| mLog.e("registerMobileNetworkRequest() already registered"); |
| return; |
| } |
| // The following use of the legacy type system cannot be removed until |
| // after upstream selection no longer finds networks by legacy type. |
| // See also http://b/34364553 . |
| final int legacyType = mDunRequired ? TYPE_MOBILE_DUN : TYPE_MOBILE_HIPRI; |
| |
| final NetworkRequest mobileUpstreamRequest = new NetworkRequest.Builder() |
| .setCapabilities(ConnectivityManager.networkCapabilitiesForType(legacyType)) |
| .build(); |
| |
| // The existing default network and DUN callbacks will be notified. |
| // Therefore, to avoid duplicate notifications, we only register a no-op. |
| mMobileNetworkCallback = new UpstreamNetworkCallback(CALLBACK_MOBILE_REQUEST); |
| |
| // TODO: Change the timeout from 0 (no onUnavailable callback) to some |
| // moderate callback timeout. This might be useful for updating some UI. |
| // Additionally, we log a message to aid in any subsequent debugging. |
| mLog.i("requesting mobile upstream network: " + mobileUpstreamRequest); |
| |
| cm().requestNetwork(mobileUpstreamRequest, mMobileNetworkCallback, 0, legacyType, mHandler); |
| } |
| |
| public void releaseMobileNetworkRequest() { |
| if (mMobileNetworkCallback == null) return; |
| |
| cm().unregisterNetworkCallback(mMobileNetworkCallback); |
| mMobileNetworkCallback = null; |
| } |
| |
| // So many TODOs here, but chief among them is: make this functionality an |
| // integral part of this class such that whenever a higher priority network |
| // becomes available and useful we (a) file a request to keep it up as |
| // necessary and (b) change all upstream tracking state accordingly (by |
| // passing LinkProperties up to Tethering). |
| public NetworkState selectPreferredUpstreamType(Iterable<Integer> preferredTypes) { |
| final TypeStatePair typeStatePair = findFirstAvailableUpstreamByType( |
| mNetworkMap.values(), preferredTypes, isCellularUpstreamPermitted()); |
| |
| mLog.log("preferred upstream type: " + getNetworkTypeName(typeStatePair.type)); |
| |
| switch (typeStatePair.type) { |
| case TYPE_MOBILE_DUN: |
| case TYPE_MOBILE_HIPRI: |
| // Tethering just selected mobile upstream in spite of the default network being |
| // not mobile. This can happen because of the priority list. |
| // Notify EntitlementManager to check permission for using mobile upstream. |
| if (!mIsDefaultCellularUpstream) { |
| mEntitlementMgr.maybeRunProvisioning(); |
| } |
| // If we're on DUN, put our own grab on it. |
| registerMobileNetworkRequest(); |
| break; |
| case TYPE_NONE: |
| // If we found NONE and mobile upstream is permitted we don't want to do this |
| // as we want any previous requests to keep trying to bring up something we can use. |
| if (!isCellularUpstreamPermitted()) releaseMobileNetworkRequest(); |
| break; |
| default: |
| // If we've found an active upstream connection that's not DUN/HIPRI |
| // we should stop any outstanding DUN/HIPRI requests. |
| releaseMobileNetworkRequest(); |
| break; |
| } |
| |
| return typeStatePair.ns; |
| } |
| |
| // Returns null if no current upstream available. |
| public NetworkState getCurrentPreferredUpstream() { |
| final NetworkState dfltState = (mDefaultInternetNetwork != null) |
| ? mNetworkMap.get(mDefaultInternetNetwork) |
| : null; |
| if (isNetworkUsableAndNotCellular(dfltState)) return dfltState; |
| |
| if (!isCellularUpstreamPermitted()) return null; |
| |
| if (!mDunRequired) return dfltState; |
| |
| // Find a DUN network. Note that code in Tethering causes a DUN request |
| // to be filed, but this might be moved into this class in future. |
| return findFirstDunNetwork(mNetworkMap.values()); |
| } |
| |
| public void setCurrentUpstream(Network upstream) { |
| mTetheringUpstreamNetwork = upstream; |
| } |
| |
| public Set<IpPrefix> getLocalPrefixes() { |
| return (Set<IpPrefix>) mLocalPrefixes.clone(); |
| } |
| |
| private boolean isCellularUpstreamPermitted() { |
| if (mEntitlementMgr != null) { |
| return mEntitlementMgr.isCellularUpstreamPermitted(); |
| } else { |
| // This flow should only happens in testing. |
| return true; |
| } |
| } |
| |
| private void handleAvailable(Network network) { |
| if (mNetworkMap.containsKey(network)) return; |
| |
| if (VDBG) Log.d(TAG, "onAvailable for " + network); |
| mNetworkMap.put(network, new NetworkState(null, null, null, network, null, null)); |
| } |
| |
| private void handleNetCap(Network network, NetworkCapabilities newNc) { |
| final NetworkState prev = mNetworkMap.get(network); |
| if (prev == null || newNc.equals(prev.networkCapabilities)) { |
| // Ignore notifications about networks for which we have not yet |
| // received onAvailable() (should never happen) and any duplicate |
| // notifications (e.g. matching more than one of our callbacks). |
| return; |
| } |
| |
| if (VDBG) { |
| Log.d(TAG, String.format("EVENT_ON_CAPABILITIES for %s: %s", |
| network, newNc)); |
| } |
| |
| // Log changes in upstream network signal strength, if available. |
| if (network.equals(mTetheringUpstreamNetwork) && newNc.hasSignalStrength()) { |
| final int newSignal = newNc.getSignalStrength(); |
| final String prevSignal = getSignalStrength(prev.networkCapabilities); |
| mLog.logf("upstream network signal strength: %s -> %s", prevSignal, newSignal); |
| } |
| |
| mNetworkMap.put(network, new NetworkState( |
| null, prev.linkProperties, newNc, network, null, null)); |
| // TODO: If sufficient information is available to select a more |
| // preferable upstream, do so now and notify the target. |
| notifyTarget(EVENT_ON_CAPABILITIES, network); |
| } |
| |
| private void handleLinkProp(Network network, LinkProperties newLp) { |
| final NetworkState prev = mNetworkMap.get(network); |
| if (prev == null || newLp.equals(prev.linkProperties)) { |
| // Ignore notifications about networks for which we have not yet |
| // received onAvailable() (should never happen) and any duplicate |
| // notifications (e.g. matching more than one of our callbacks). |
| return; |
| } |
| |
| if (VDBG) { |
| Log.d(TAG, String.format("EVENT_ON_LINKPROPERTIES for %s: %s", |
| network, newLp)); |
| } |
| |
| mNetworkMap.put(network, new NetworkState( |
| null, newLp, prev.networkCapabilities, network, null, null)); |
| // TODO: If sufficient information is available to select a more |
| // preferable upstream, do so now and notify the target. |
| notifyTarget(EVENT_ON_LINKPROPERTIES, network); |
| } |
| |
| private void handleSuspended(Network network) { |
| if (!network.equals(mTetheringUpstreamNetwork)) return; |
| mLog.log("SUSPENDED current upstream: " + network); |
| } |
| |
| private void handleResumed(Network network) { |
| if (!network.equals(mTetheringUpstreamNetwork)) return; |
| mLog.log("RESUMED current upstream: " + network); |
| } |
| |
| private void handleLost(Network network) { |
| // There are few TODOs within ConnectivityService's rematching code |
| // pertaining to spurious onLost() notifications. |
| // |
| // TODO: simplify this, probably if favor of code that: |
| // - selects a new upstream if mTetheringUpstreamNetwork has |
| // been lost (by any callback) |
| // - deletes the entry from the map only when the LISTEN_ALL |
| // callback gets notified. |
| |
| if (!mNetworkMap.containsKey(network)) { |
| // Ignore loss of networks about which we had not previously |
| // learned any information or for which we have already processed |
| // an onLost() notification. |
| return; |
| } |
| |
| if (VDBG) Log.d(TAG, "EVENT_ON_LOST for " + network); |
| |
| // TODO: If sufficient information is available to select a more |
| // preferable upstream, do so now and notify the target. Likewise, |
| // if the current upstream network is gone, notify the target of the |
| // fact that we now have no upstream at all. |
| notifyTarget(EVENT_ON_LOST, mNetworkMap.remove(network)); |
| } |
| |
| private void recomputeLocalPrefixes() { |
| final HashSet<IpPrefix> localPrefixes = allLocalPrefixes(mNetworkMap.values()); |
| if (!mLocalPrefixes.equals(localPrefixes)) { |
| mLocalPrefixes = localPrefixes; |
| notifyTarget(NOTIFY_LOCAL_PREFIXES, localPrefixes.clone()); |
| } |
| } |
| |
| // Fetch (and cache) a ConnectivityManager only if and when we need one. |
| private ConnectivityManager cm() { |
| if (mCM == null) { |
| // MUST call the String variant to be able to write unittests. |
| mCM = (ConnectivityManager) mContext.getSystemService(Context.CONNECTIVITY_SERVICE); |
| } |
| return mCM; |
| } |
| |
| /** |
| * A NetworkCallback class that handles information of interest directly |
| * in the thread on which it is invoked. To avoid locking, this MUST be |
| * run on the same thread as the target state machine's handler. |
| */ |
| private class UpstreamNetworkCallback extends NetworkCallback { |
| private final int mCallbackType; |
| |
| UpstreamNetworkCallback(int callbackType) { |
| mCallbackType = callbackType; |
| } |
| |
| @Override |
| public void onAvailable(Network network) { |
| handleAvailable(network); |
| } |
| |
| @Override |
| public void onCapabilitiesChanged(Network network, NetworkCapabilities newNc) { |
| if (mCallbackType == CALLBACK_DEFAULT_INTERNET) { |
| mDefaultInternetNetwork = network; |
| final boolean newIsCellular = isCellular(newNc); |
| if (mIsDefaultCellularUpstream != newIsCellular) { |
| mIsDefaultCellularUpstream = newIsCellular; |
| mEntitlementMgr.notifyUpstream(newIsCellular); |
| } |
| return; |
| } |
| |
| handleNetCap(network, newNc); |
| } |
| |
| @Override |
| public void onLinkPropertiesChanged(Network network, LinkProperties newLp) { |
| if (mCallbackType == CALLBACK_DEFAULT_INTERNET) return; |
| |
| handleLinkProp(network, newLp); |
| // Any non-LISTEN_ALL callback will necessarily concern a network that will |
| // also match the LISTEN_ALL callback by construction of the LISTEN_ALL callback. |
| // So it's not useful to do this work for non-LISTEN_ALL callbacks. |
| if (mCallbackType == CALLBACK_LISTEN_ALL) { |
| recomputeLocalPrefixes(); |
| } |
| } |
| |
| @Override |
| public void onNetworkSuspended(Network network) { |
| if (mCallbackType == CALLBACK_LISTEN_ALL) { |
| handleSuspended(network); |
| } |
| } |
| |
| @Override |
| public void onNetworkResumed(Network network) { |
| if (mCallbackType == CALLBACK_LISTEN_ALL) { |
| handleResumed(network); |
| } |
| } |
| |
| @Override |
| public void onLost(Network network) { |
| if (mCallbackType == CALLBACK_DEFAULT_INTERNET) { |
| mDefaultInternetNetwork = null; |
| mIsDefaultCellularUpstream = false; |
| mEntitlementMgr.notifyUpstream(false); |
| return; |
| } |
| |
| handleLost(network); |
| // Any non-LISTEN_ALL callback will necessarily concern a network that will |
| // also match the LISTEN_ALL callback by construction of the LISTEN_ALL callback. |
| // So it's not useful to do this work for non-LISTEN_ALL callbacks. |
| if (mCallbackType == CALLBACK_LISTEN_ALL) { |
| recomputeLocalPrefixes(); |
| } |
| } |
| } |
| |
| private void releaseCallback(NetworkCallback cb) { |
| if (cb != null) cm().unregisterNetworkCallback(cb); |
| } |
| |
| private void notifyTarget(int which, Network network) { |
| notifyTarget(which, mNetworkMap.get(network)); |
| } |
| |
| private void notifyTarget(int which, Object obj) { |
| mTarget.sendMessage(mWhat, which, 0, obj); |
| } |
| |
| private static class TypeStatePair { |
| public int type = TYPE_NONE; |
| public NetworkState ns = null; |
| } |
| |
| private static TypeStatePair findFirstAvailableUpstreamByType( |
| Iterable<NetworkState> netStates, Iterable<Integer> preferredTypes, |
| boolean isCellularUpstreamPermitted) { |
| final TypeStatePair result = new TypeStatePair(); |
| |
| for (int type : preferredTypes) { |
| NetworkCapabilities nc; |
| try { |
| nc = ConnectivityManager.networkCapabilitiesForType(type); |
| } catch (IllegalArgumentException iae) { |
| Log.e(TAG, "No NetworkCapabilities mapping for legacy type: " + |
| ConnectivityManager.getNetworkTypeName(type)); |
| continue; |
| } |
| if (!isCellularUpstreamPermitted && isCellular(nc)) { |
| continue; |
| } |
| |
| nc.setSingleUid(Process.myUid()); |
| |
| for (NetworkState value : netStates) { |
| if (!nc.satisfiedByNetworkCapabilities(value.networkCapabilities)) { |
| continue; |
| } |
| |
| result.type = type; |
| result.ns = value; |
| return result; |
| } |
| } |
| |
| return result; |
| } |
| |
| private static HashSet<IpPrefix> allLocalPrefixes(Iterable<NetworkState> netStates) { |
| final HashSet<IpPrefix> prefixSet = new HashSet<>(); |
| |
| for (NetworkState ns : netStates) { |
| final LinkProperties lp = ns.linkProperties; |
| if (lp == null) continue; |
| prefixSet.addAll(PrefixUtils.localPrefixesFrom(lp)); |
| } |
| |
| return prefixSet; |
| } |
| |
| private static String getSignalStrength(NetworkCapabilities nc) { |
| if (nc == null || !nc.hasSignalStrength()) return "unknown"; |
| return Integer.toString(nc.getSignalStrength()); |
| } |
| |
| private static boolean isCellular(NetworkState ns) { |
| return (ns != null) && isCellular(ns.networkCapabilities); |
| } |
| |
| private static boolean isCellular(NetworkCapabilities nc) { |
| return (nc != null) && nc.hasTransport(TRANSPORT_CELLULAR) && |
| nc.hasCapability(NET_CAPABILITY_NOT_VPN); |
| } |
| |
| private static boolean hasCapability(NetworkState ns, int netCap) { |
| return (ns != null) && (ns.networkCapabilities != null) && |
| ns.networkCapabilities.hasCapability(netCap); |
| } |
| |
| private static boolean isNetworkUsableAndNotCellular(NetworkState ns) { |
| return (ns != null) && (ns.networkCapabilities != null) && (ns.linkProperties != null) && |
| !isCellular(ns.networkCapabilities); |
| } |
| |
| private static NetworkState findFirstDunNetwork(Iterable<NetworkState> netStates) { |
| for (NetworkState ns : netStates) { |
| if (isCellular(ns) && hasCapability(ns, NET_CAPABILITY_DUN)) return ns; |
| } |
| |
| return null; |
| } |
| } |