| /* |
| * 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.getNetworkTypeName; |
| import static android.net.ConnectivityManager.TYPE_NONE; |
| import static android.net.ConnectivityManager.TYPE_MOBILE_DUN; |
| import static android.net.ConnectivityManager.TYPE_MOBILE_HIPRI; |
| |
| import android.content.Context; |
| import android.os.Handler; |
| import android.os.Looper; |
| import android.net.ConnectivityManager; |
| import android.net.ConnectivityManager.NetworkCallback; |
| import android.net.IpPrefix; |
| import android.net.LinkAddress; |
| import android.net.LinkProperties; |
| import android.net.Network; |
| import android.net.NetworkCapabilities; |
| import android.net.NetworkRequest; |
| import android.net.NetworkState; |
| import android.net.util.NetworkConstants; |
| import android.net.util.SharedLog; |
| import android.util.Log; |
| |
| import com.android.internal.annotations.VisibleForTesting; |
| import com.android.internal.util.StateMachine; |
| |
| import java.util.Collections; |
| 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. |
| * |
| * Calling #start() registers two callbacks: one to track the system default |
| * network and a second to observe all networks. The latter is necessary |
| * while the expression of preferred upstreams remains a list of legacy |
| * connectivity types. In future, this can be revisited. |
| * |
| * 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; |
| |
| private static final IpPrefix[] MINIMUM_LOCAL_PREFIXES_SET = { |
| prefix("127.0.0.0/8"), prefix("169.254.0.0/16"), |
| prefix("::/3"), prefix("fe80::/64"), prefix("fc00::/7"), prefix("ff00::/8"), |
| }; |
| |
| public static final int EVENT_ON_AVAILABLE = 1; |
| public static final int EVENT_ON_CAPABILITIES = 2; |
| public static final int EVENT_ON_LINKPROPERTIES = 3; |
| public static final int EVENT_ON_LOST = 4; |
| public static final int NOTIFY_EXEMPT_PREFIXES = 10; |
| |
| private static final int CALLBACK_LISTEN_ALL = 1; |
| private static final int CALLBACK_TRACK_DEFAULT = 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> mOffloadExemptPrefixes; |
| private ConnectivityManager mCM; |
| private NetworkCallback mListenAllCallback; |
| private NetworkCallback mDefaultNetworkCallback; |
| private NetworkCallback mMobileNetworkCallback; |
| private boolean mDunRequired; |
| private Network mCurrentDefault; |
| |
| public UpstreamNetworkMonitor(Context ctx, StateMachine tgt, SharedLog log, int what) { |
| mContext = ctx; |
| mTarget = tgt; |
| mHandler = mTarget.getHandler(); |
| mLog = log.forSubComponent(TAG); |
| mWhat = what; |
| mOffloadExemptPrefixes = allOffloadExemptPrefixes(mNetworkMap.values()); |
| } |
| |
| @VisibleForTesting |
| public UpstreamNetworkMonitor( |
| ConnectivityManager cm, StateMachine tgt, SharedLog log, int what) { |
| this((Context) null, tgt, log, what); |
| mCM = cm; |
| } |
| |
| public void start() { |
| stop(); |
| |
| final NetworkRequest listenAllRequest = new NetworkRequest.Builder() |
| .clearCapabilities().build(); |
| mListenAllCallback = new UpstreamNetworkCallback(CALLBACK_LISTEN_ALL); |
| cm().registerNetworkCallback(listenAllRequest, mListenAllCallback, mHandler); |
| |
| mDefaultNetworkCallback = new UpstreamNetworkCallback(CALLBACK_TRACK_DEFAULT); |
| cm().registerDefaultNetworkCallback(mDefaultNetworkCallback, mHandler); |
| } |
| |
| public void stop() { |
| releaseMobileNetworkRequest(); |
| |
| releaseCallback(mDefaultNetworkCallback); |
| mDefaultNetworkCallback = null; |
| |
| releaseCallback(mListenAllCallback); |
| mListenAllCallback = 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 (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). |
| // |
| // Next TODO: return NetworkState instead of just the type. |
| public NetworkState selectPreferredUpstreamType(Iterable<Integer> preferredTypes) { |
| final TypeStatePair typeStatePair = findFirstAvailableUpstreamByType( |
| mNetworkMap.values(), preferredTypes); |
| |
| mLog.log("preferred upstream type: " + getNetworkTypeName(typeStatePair.type)); |
| |
| switch (typeStatePair.type) { |
| case TYPE_MOBILE_DUN: |
| case TYPE_MOBILE_HIPRI: |
| // If we're on DUN, put our own grab on it. |
| registerMobileNetworkRequest(); |
| break; |
| case TYPE_NONE: |
| break; |
| default: |
| /* If we've found an active upstream connection that's not DUN/HIPRI |
| * we should stop any outstanding DUN/HIPRI start requests. |
| * |
| * If we found NONE we don't want to do this as we want any previous |
| * requests to keep trying to bring up something we can use. |
| */ |
| releaseMobileNetworkRequest(); |
| break; |
| } |
| |
| return typeStatePair.ns; |
| } |
| |
| public Set<IpPrefix> getOffloadExemptPrefixes() { |
| return (Set<IpPrefix>) mOffloadExemptPrefixes.clone(); |
| } |
| |
| private void handleAvailable(int callbackType, Network network) { |
| if (VDBG) Log.d(TAG, "EVENT_ON_AVAILABLE for " + network); |
| |
| if (!mNetworkMap.containsKey(network)) { |
| mNetworkMap.put(network, |
| new NetworkState(null, null, null, network, null, null)); |
| } |
| |
| // Always request whatever extra information we can, in case this |
| // was already up when start() was called, in which case we would |
| // not have been notified of any information that had not changed. |
| switch (callbackType) { |
| case CALLBACK_LISTEN_ALL: |
| break; |
| |
| case CALLBACK_TRACK_DEFAULT: |
| if (mDefaultNetworkCallback == null) { |
| // The callback was unregistered in the interval between |
| // ConnectivityService enqueueing onAvailable() and our |
| // handling of it here on the mHandler thread. |
| // |
| // Clean-up of this network entry is deferred to the |
| // handling of onLost() by other callbacks. |
| // |
| // These request*() calls can be deleted post oag/339444. |
| return; |
| } |
| mCurrentDefault = network; |
| break; |
| |
| case CALLBACK_MOBILE_REQUEST: |
| if (mMobileNetworkCallback == null) { |
| // The callback was unregistered in the interval between |
| // ConnectivityService enqueueing onAvailable() and our |
| // handling of it here on the mHandler thread. |
| // |
| // Clean-up of this network entry is deferred to the |
| // handling of onLost() by other callbacks. |
| return; |
| } |
| break; |
| } |
| |
| // Requesting updates for mListenAllCallback is not currently possible |
| // because it's a "listen". Two possible solutions to getting updates |
| // about networks without waiting for a change (which might never come) |
| // are: |
| // |
| // [1] extend request{NetworkCapabilities,LinkProperties}() to |
| // take a Network argument and have ConnectivityService do |
| // what's required (if the network satisfies the request) |
| // |
| // [2] explicitly file a NetworkRequest for each connectivity type |
| // listed as a preferred upstream and wait for these callbacks |
| // to be notified (requires tracking many more callbacks). |
| // |
| // Until this is addressed, networks that exist prior to the "listen" |
| // registration and which do not subsequently change will not cause |
| // us to learn their NetworkCapabilities nor their LinkProperties. |
| |
| // TODO: If sufficient information is available to select a more |
| // preferable upstream, do so now and notify the target. |
| notifyTarget(EVENT_ON_AVAILABLE, network); |
| } |
| |
| 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)); |
| } |
| |
| 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 handleLost(int callbackType, Network network) { |
| if (callbackType == CALLBACK_TRACK_DEFAULT) { |
| mCurrentDefault = null; |
| // Receiving onLost() for a default network does not necessarily |
| // mean the network is gone. We wait for a separate notification |
| // on either the LISTEN_ALL or MOBILE_REQUEST callbacks before |
| // clearing all state. |
| return; |
| } |
| |
| 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 recomputeOffloadExemptPrefixes() { |
| final HashSet<IpPrefix> exemptPrefixes = allOffloadExemptPrefixes(mNetworkMap.values()); |
| if (!mOffloadExemptPrefixes.equals(exemptPrefixes)) { |
| mOffloadExemptPrefixes = exemptPrefixes; |
| notifyTarget(NOTIFY_EXEMPT_PREFIXES, exemptPrefixes.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(mCallbackType, network); |
| } |
| |
| @Override |
| public void onCapabilitiesChanged(Network network, NetworkCapabilities newNc) { |
| handleNetCap(network, newNc); |
| } |
| |
| @Override |
| public void onLinkPropertiesChanged(Network network, LinkProperties newLp) { |
| handleLinkProp(network, newLp); |
| recomputeOffloadExemptPrefixes(); |
| } |
| |
| // TODO: Handle onNetworkSuspended(); |
| // TODO: Handle onNetworkResumed(); |
| |
| @Override |
| public void onLost(Network network) { |
| handleLost(mCallbackType, network); |
| recomputeOffloadExemptPrefixes(); |
| } |
| } |
| |
| 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) { |
| 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; |
| } |
| |
| for (NetworkState value : netStates) { |
| if (!nc.satisfiedByNetworkCapabilities(value.networkCapabilities)) { |
| continue; |
| } |
| |
| result.type = type; |
| result.ns = value; |
| return result; |
| } |
| } |
| |
| return result; |
| } |
| |
| private static HashSet<IpPrefix> allOffloadExemptPrefixes(Iterable<NetworkState> netStates) { |
| final HashSet<IpPrefix> prefixSet = new HashSet<>(); |
| |
| addDefaultLocalPrefixes(prefixSet); |
| |
| for (NetworkState ns : netStates) { |
| addOffloadExemptPrefixes(prefixSet, ns.linkProperties); |
| } |
| |
| return prefixSet; |
| } |
| |
| private static void addDefaultLocalPrefixes(Set<IpPrefix> prefixSet) { |
| Collections.addAll(prefixSet, MINIMUM_LOCAL_PREFIXES_SET); |
| } |
| |
| private static void addOffloadExemptPrefixes(Set<IpPrefix> prefixSet, LinkProperties lp) { |
| if (lp == null) return; |
| |
| for (LinkAddress linkAddr : lp.getAllLinkAddresses()) { |
| prefixSet.add(new IpPrefix(linkAddr.getAddress(), linkAddr.getPrefixLength())); |
| } |
| |
| // TODO: Consider adding other non-default routes associated with this |
| // network. Traffic to these destinations should perhaps not go through |
| // the Internet (upstream). |
| } |
| |
| private static IpPrefix prefix(String prefixStr) { |
| return new IpPrefix(prefixStr); |
| } |
| } |