services/net/java/android/net/NetworkStackClient.java - platform/frameworks/base - Git at Google

 /*
  * Copyright (C) 2019 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 static android.content.pm.PackageManager.PERMISSION_GRANTED;
 import static android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK;
 import static android.os.IServiceManager.DUMP_FLAG_PRIORITY_HIGH;
 import static android.os.IServiceManager.DUMP_FLAG_PRIORITY_NORMAL;

 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
 import android.content.ServiceConnection;
 import android.content.pm.PackageManager;
 import android.net.dhcp.DhcpServingParamsParcel;
 import android.net.dhcp.IDhcpServerCallbacks;
 import android.net.ip.IIpClientCallbacks;
 import android.net.util.SharedLog;
 import android.os.Binder;
 import android.os.IBinder;
 import android.os.Process;
 import android.os.RemoteException;
 import android.os.ServiceManager;
 import android.os.UserHandle;
 import android.util.Slog;

 import com.android.internal.annotations.GuardedBy;

 import java.io.PrintWriter;
 import java.util.ArrayList;

 /**
  * Service used to communicate with the network stack, which is running in a separate module.
  * @hide
  */
 public class NetworkStackClient {
     private static final String TAG = NetworkStackClient.class.getSimpleName();

     private static final int NETWORKSTACK_TIMEOUT_MS = 10_000;
     private static final String IN_PROCESS_SUFFIX = ".InProcess";

     private static NetworkStackClient sInstance;

     @NonNull
     @GuardedBy("mPendingNetStackRequests")
     private final ArrayList<NetworkStackCallback> mPendingNetStackRequests = new ArrayList<>();
     @Nullable
     @GuardedBy("mPendingNetStackRequests")
     private INetworkStackConnector mConnector;

     @GuardedBy("mLog")
     private final SharedLog mLog = new SharedLog(TAG);

     private volatile boolean mNetworkStackStartRequested = false;

     private interface NetworkStackCallback {
         void onNetworkStackConnected(INetworkStackConnector connector);
     }

     private NetworkStackClient() { }

     /**
      * Get the NetworkStackClient singleton instance.
      */
     public static synchronized NetworkStackClient getInstance() {
         if (sInstance == null) {
             sInstance = new NetworkStackClient();
         }
         return sInstance;
     }

     /**
      * Create a DHCP server according to the specified parameters.
      *
      * <p>The server will be returned asynchronously through the provided callbacks.
      */
     public void makeDhcpServer(final String ifName, final DhcpServingParamsParcel params,
             final IDhcpServerCallbacks cb) {
         requestConnector(connector -> {
             try {
                 connector.makeDhcpServer(ifName, params, cb);
             } catch (RemoteException e) {
                 e.rethrowFromSystemServer();
             }
         });
     }

     /**
      * Create an IpClient on the specified interface.
      *
      * <p>The IpClient will be returned asynchronously through the provided callbacks.
      */
     public void makeIpClient(String ifName, IIpClientCallbacks cb) {
         requestConnector(connector -> {
             try {
                 connector.makeIpClient(ifName, cb);
             } catch (RemoteException e) {
                 e.rethrowFromSystemServer();
             }
         });
     }

     /**
      * Create a NetworkMonitor.
      *
      * <p>The INetworkMonitor will be returned asynchronously through the provided callbacks.
      */
     public void makeNetworkMonitor(
             NetworkParcelable network, String name, INetworkMonitorCallbacks cb) {
         requestConnector(connector -> {
             try {
                 connector.makeNetworkMonitor(network, name, cb);
             } catch (RemoteException e) {
                 e.rethrowFromSystemServer();
             }
         });
     }

     private class NetworkStackConnection implements ServiceConnection {
         @Override
         public void onServiceConnected(ComponentName name, IBinder service) {
             log("Network stack service connected");
             registerNetworkStackService(service);
         }

         @Override
         public void onServiceDisconnected(ComponentName name) {
             // TODO: crash/reboot the system ?
             logWtf("Lost network stack connector", null);
         }
     };

     private void registerNetworkStackService(@NonNull IBinder service) {
         final INetworkStackConnector connector = INetworkStackConnector.Stub.asInterface(service);

         ServiceManager.addService(Context.NETWORK_STACK_SERVICE, service, false /* allowIsolated */,
                 DUMP_FLAG_PRIORITY_HIGH | DUMP_FLAG_PRIORITY_NORMAL);
         log("Network stack service registered");

         final ArrayList<NetworkStackCallback> requests;
         synchronized (mPendingNetStackRequests) {
             requests = new ArrayList<>(mPendingNetStackRequests);
             mPendingNetStackRequests.clear();
             mConnector = connector;
         }

         for (NetworkStackCallback r : requests) {
             r.onNetworkStackConnected(connector);
         }
     }

     /**
      * Initialize the network stack. Should be called only once on device startup, before any
      * client attempts to use the network stack.
      */
     public void init() {
         log("Network stack init");
         mNetworkStackStartRequested = true;
     }

     /**
      * Start the network stack. Should be called only once on device startup.
      *
      * <p>This method will start the network stack either in the network stack process, or inside
      * the system server on devices that do not support the network stack module. The network stack
      * connector will then be delivered asynchronously to clients that requested it before it was
      * started.
      */
     public void start(Context context) {
         log("Starting network stack");
         final PackageManager pm = context.getPackageManager();

         // Try to bind in-process if the device was shipped with an in-process version
         Intent intent = getNetworkStackIntent(pm, true /* inSystemProcess */);

         // Otherwise use the updatable module version
         if (intent == null) {
             intent = getNetworkStackIntent(pm, false /* inSystemProcess */);
             log("Starting network stack process");
         } else {
             log("Starting network stack in-process");
         }

         if (intent == null) {
             logWtf("Could not resolve the network stack", null);
             // TODO: crash/reboot system server ?
             return;
         }

         // Start the network stack. The service will be added to the service manager in
         // NetworkStackConnection.onServiceConnected().
         if (!context.bindServiceAsUser(intent, new NetworkStackConnection(),
                 Context.BIND_AUTO_CREATE | Context.BIND_IMPORTANT, UserHandle.SYSTEM)) {
             logWtf("Could not bind to network stack with " + intent, null);
             return;
             // TODO: crash/reboot system server if no network stack after a timeout ?
         }

         log("Network stack service start requested");
     }

     @Nullable
     private Intent getNetworkStackIntent(@NonNull PackageManager pm, boolean inSystemProcess) {
         final String baseAction = INetworkStackConnector.class.getName();
         final Intent intent =
                 new Intent(inSystemProcess ? baseAction + IN_PROCESS_SUFFIX : baseAction);
         final ComponentName comp = intent.resolveSystemService(pm, 0);

         if (comp == null) {
             return null;
         }
         intent.setComponent(comp);

         int uid = -1;
         try {
             uid = pm.getPackageUidAsUser(comp.getPackageName(), UserHandle.USER_SYSTEM);
         } catch (PackageManager.NameNotFoundException e) {
             logWtf("Network stack package not found", e);
             // Fall through
         }

         final int expectedUid = inSystemProcess ? Process.SYSTEM_UID : Process.NETWORK_STACK_UID;
         if (uid != expectedUid) {
             throw new SecurityException("Invalid network stack UID: " + uid);
         }

         if (!inSystemProcess) {
             checkNetworkStackPermission(pm, comp);
         }

         return intent;
     }

     private void checkNetworkStackPermission(
             @NonNull PackageManager pm, @NonNull ComponentName comp) {
         final int hasPermission =
                 pm.checkPermission(PERMISSION_MAINLINE_NETWORK_STACK, comp.getPackageName());
         if (hasPermission != PERMISSION_GRANTED) {
             throw new SecurityException(
                     "Network stack does not have permission " + PERMISSION_MAINLINE_NETWORK_STACK);
         }
     }

     private void log(@NonNull String message) {
         synchronized (mLog) {
             mLog.log(message);
         }
     }

     private void logWtf(@NonNull String message, @Nullable Throwable e) {
         Slog.wtf(TAG, message);
         synchronized (mLog) {
             mLog.e(message, e);
         }
     }

     private void loge(@NonNull String message, @Nullable Throwable e) {
         synchronized (mLog) {
             mLog.e(message, e);
         }
     }

     /**
      * For non-system server clients, get the connector registered by the system server.
      */
     private INetworkStackConnector getRemoteConnector() {
         // Block until the NetworkStack connector is registered in ServiceManager.
         // <p>This is only useful for non-system processes that do not have a way to be notified of
         // registration completion. Adding a callback system would be too heavy weight considering
         // that the connector is registered on boot, so it is unlikely that a client would request
         // it before it is registered.
         // TODO: consider blocking boot on registration and simplify much of the logic in this class
         IBinder connector;
         try {
             final long before = System.currentTimeMillis();
             while ((connector = ServiceManager.getService(Context.NETWORK_STACK_SERVICE)) == null) {
                 Thread.sleep(20);
                 if (System.currentTimeMillis() - before > NETWORKSTACK_TIMEOUT_MS) {
                     loge("Timeout waiting for NetworkStack connector", null);
                     return null;
                 }
             }
         } catch (InterruptedException e) {
             loge("Error waiting for NetworkStack connector", e);
             return null;
         }

         return INetworkStackConnector.Stub.asInterface(connector);
     }

     private void requestConnector(@NonNull NetworkStackCallback request) {
         // TODO: PID check.
         final int caller = Binder.getCallingUid();
         if (caller != Process.SYSTEM_UID && !UserHandle.isSameApp(caller, Process.BLUETOOTH_UID)
                 && !UserHandle.isSameApp(caller, Process.PHONE_UID)) {
             // Don't even attempt to obtain the connector and give a nice error message
             throw new SecurityException(
                     "Only the system server should try to bind to the network stack.");
         }

         if (!mNetworkStackStartRequested) {
             // The network stack is not being started in this process, e.g. this process is not
             // the system server. Get a remote connector registered by the system server.
             final INetworkStackConnector connector = getRemoteConnector();
             synchronized (mPendingNetStackRequests) {
                 mConnector = connector;
             }
             request.onNetworkStackConnected(connector);
             return;
         }

         final INetworkStackConnector connector;
         synchronized (mPendingNetStackRequests) {
             connector = mConnector;
             if (connector == null) {
                 mPendingNetStackRequests.add(request);
                 return;
             }
         }

         request.onNetworkStackConnected(connector);
     }

     /**
      * Dump NetworkStackClient logs to the specified {@link PrintWriter}.
      */
     public void dump(PrintWriter pw) {
         // dump is thread-safe on SharedLog
         mLog.dump(null, pw, null);

         final int requestsQueueLength;
         synchronized (mPendingNetStackRequests) {
             requestsQueueLength = mPendingNetStackRequests.size();
         }

         pw.println();
         pw.println("pendingNetStackRequests length: " + requestsQueueLength);
     }
 }
	/*
	* Copyright (C) 2019 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 static android.content.pm.PackageManager.PERMISSION_GRANTED;
	import static android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK;
	import static android.os.IServiceManager.DUMP_FLAG_PRIORITY_HIGH;
	import static android.os.IServiceManager.DUMP_FLAG_PRIORITY_NORMAL;

	import android.annotation.NonNull;
	import android.annotation.Nullable;
	import android.content.ComponentName;
	import android.content.Context;
	import android.content.Intent;
	import android.content.ServiceConnection;
	import android.content.pm.PackageManager;
	import android.net.dhcp.DhcpServingParamsParcel;
	import android.net.dhcp.IDhcpServerCallbacks;
	import android.net.ip.IIpClientCallbacks;
	import android.net.util.SharedLog;
	import android.os.Binder;
	import android.os.IBinder;
	import android.os.Process;
	import android.os.RemoteException;
	import android.os.ServiceManager;
	import android.os.UserHandle;
	import android.util.Slog;

	import com.android.internal.annotations.GuardedBy;

	import java.io.PrintWriter;
	import java.util.ArrayList;

	/**
	* Service used to communicate with the network stack, which is running in a separate module.
	* @hide
	*/
	public class NetworkStackClient {
	private static final String TAG = NetworkStackClient.class.getSimpleName();

	private static final int NETWORKSTACK_TIMEOUT_MS = 10_000;
	private static final String IN_PROCESS_SUFFIX = ".InProcess";

	private static NetworkStackClient sInstance;

	@NonNull
	@GuardedBy("mPendingNetStackRequests")
	private final ArrayList<NetworkStackCallback> mPendingNetStackRequests = new ArrayList<>();
	@Nullable
	@GuardedBy("mPendingNetStackRequests")
	private INetworkStackConnector mConnector;

	@GuardedBy("mLog")
	private final SharedLog mLog = new SharedLog(TAG);

	private volatile boolean mNetworkStackStartRequested = false;

	private interface NetworkStackCallback {
	void onNetworkStackConnected(INetworkStackConnector connector);
	}

	private NetworkStackClient() { }

	/**
	* Get the NetworkStackClient singleton instance.
	*/
	public static synchronized NetworkStackClient getInstance() {
	if (sInstance == null) {
	sInstance = new NetworkStackClient();
	}
	return sInstance;
	}

	/**
	* Create a DHCP server according to the specified parameters.
	*
	* <p>The server will be returned asynchronously through the provided callbacks.
	*/
	public void makeDhcpServer(final String ifName, final DhcpServingParamsParcel params,
	final IDhcpServerCallbacks cb) {
	requestConnector(connector -> {
	try {
	connector.makeDhcpServer(ifName, params, cb);
	} catch (RemoteException e) {
	e.rethrowFromSystemServer();
	}
	});
	}

	/**
	* Create an IpClient on the specified interface.
	*
	* <p>The IpClient will be returned asynchronously through the provided callbacks.
	*/
	public void makeIpClient(String ifName, IIpClientCallbacks cb) {
	requestConnector(connector -> {
	try {
	connector.makeIpClient(ifName, cb);
	} catch (RemoteException e) {
	e.rethrowFromSystemServer();
	}
	});
	}

	/**
	* Create a NetworkMonitor.
	*
	* <p>The INetworkMonitor will be returned asynchronously through the provided callbacks.
	*/
	public void makeNetworkMonitor(
	NetworkParcelable network, String name, INetworkMonitorCallbacks cb) {
	requestConnector(connector -> {
	try {
	connector.makeNetworkMonitor(network, name, cb);
	} catch (RemoteException e) {
	e.rethrowFromSystemServer();
	}
	});
	}

	private class NetworkStackConnection implements ServiceConnection {
	@Override
	public void onServiceConnected(ComponentName name, IBinder service) {
	log("Network stack service connected");
	registerNetworkStackService(service);
	}

	@Override
	public void onServiceDisconnected(ComponentName name) {
	// TODO: crash/reboot the system ?
	logWtf("Lost network stack connector", null);
	}
	};

	private void registerNetworkStackService(@NonNull IBinder service) {
	final INetworkStackConnector connector = INetworkStackConnector.Stub.asInterface(service);

	ServiceManager.addService(Context.NETWORK_STACK_SERVICE, service, false /* allowIsolated */,
	DUMP_FLAG_PRIORITY_HIGH \| DUMP_FLAG_PRIORITY_NORMAL);
	log("Network stack service registered");

	final ArrayList<NetworkStackCallback> requests;
	synchronized (mPendingNetStackRequests) {
	requests = new ArrayList<>(mPendingNetStackRequests);
	mPendingNetStackRequests.clear();
	mConnector = connector;
	}

	for (NetworkStackCallback r : requests) {
	r.onNetworkStackConnected(connector);
	}
	}

	/**
	* Initialize the network stack. Should be called only once on device startup, before any
	* client attempts to use the network stack.
	*/
	public void init() {
	log("Network stack init");
	mNetworkStackStartRequested = true;
	}

	/**
	* Start the network stack. Should be called only once on device startup.
	*
	* <p>This method will start the network stack either in the network stack process, or inside
	* the system server on devices that do not support the network stack module. The network stack
	* connector will then be delivered asynchronously to clients that requested it before it was
	* started.
	*/
	public void start(Context context) {
	log("Starting network stack");
	final PackageManager pm = context.getPackageManager();

	// Try to bind in-process if the device was shipped with an in-process version
	Intent intent = getNetworkStackIntent(pm, true /* inSystemProcess */);

	// Otherwise use the updatable module version
	if (intent == null) {
	intent = getNetworkStackIntent(pm, false /* inSystemProcess */);
	log("Starting network stack process");
	} else {
	log("Starting network stack in-process");
	}

	if (intent == null) {
	logWtf("Could not resolve the network stack", null);
	// TODO: crash/reboot system server ?
	return;
	}

	// Start the network stack. The service will be added to the service manager in
	// NetworkStackConnection.onServiceConnected().
	if (!context.bindServiceAsUser(intent, new NetworkStackConnection(),
	Context.BIND_AUTO_CREATE \| Context.BIND_IMPORTANT, UserHandle.SYSTEM)) {
	logWtf("Could not bind to network stack with " + intent, null);
	return;
	// TODO: crash/reboot system server if no network stack after a timeout ?
	}

	log("Network stack service start requested");
	}

	@Nullable
	private Intent getNetworkStackIntent(@NonNull PackageManager pm, boolean inSystemProcess) {
	final String baseAction = INetworkStackConnector.class.getName();
	final Intent intent =
	new Intent(inSystemProcess ? baseAction + IN_PROCESS_SUFFIX : baseAction);
	final ComponentName comp = intent.resolveSystemService(pm, 0);

	if (comp == null) {
	return null;
	}
	intent.setComponent(comp);

	int uid = -1;
	try {
	uid = pm.getPackageUidAsUser(comp.getPackageName(), UserHandle.USER_SYSTEM);
	} catch (PackageManager.NameNotFoundException e) {
	logWtf("Network stack package not found", e);
	// Fall through
	}

	final int expectedUid = inSystemProcess ? Process.SYSTEM_UID : Process.NETWORK_STACK_UID;
	if (uid != expectedUid) {
	throw new SecurityException("Invalid network stack UID: " + uid);
	}

	if (!inSystemProcess) {
	checkNetworkStackPermission(pm, comp);
	}

	return intent;
	}

	private void checkNetworkStackPermission(
	@NonNull PackageManager pm, @NonNull ComponentName comp) {
	final int hasPermission =
	pm.checkPermission(PERMISSION_MAINLINE_NETWORK_STACK, comp.getPackageName());
	if (hasPermission != PERMISSION_GRANTED) {
	throw new SecurityException(
	"Network stack does not have permission " + PERMISSION_MAINLINE_NETWORK_STACK);
	}
	}

	private void log(@NonNull String message) {
	synchronized (mLog) {
	mLog.log(message);
	}
	}

	private void logWtf(@NonNull String message, @Nullable Throwable e) {
	Slog.wtf(TAG, message);
	synchronized (mLog) {
	mLog.e(message, e);
	}
	}

	private void loge(@NonNull String message, @Nullable Throwable e) {
	synchronized (mLog) {
	mLog.e(message, e);
	}
	}

	/**
	* For non-system server clients, get the connector registered by the system server.
	*/
	private INetworkStackConnector getRemoteConnector() {
	// Block until the NetworkStack connector is registered in ServiceManager.
	// <p>This is only useful for non-system processes that do not have a way to be notified of
	// registration completion. Adding a callback system would be too heavy weight considering
	// that the connector is registered on boot, so it is unlikely that a client would request
	// it before it is registered.
	// TODO: consider blocking boot on registration and simplify much of the logic in this class
	IBinder connector;
	try {
	final long before = System.currentTimeMillis();
	while ((connector = ServiceManager.getService(Context.NETWORK_STACK_SERVICE)) == null) {
	Thread.sleep(20);
	if (System.currentTimeMillis() - before > NETWORKSTACK_TIMEOUT_MS) {
	loge("Timeout waiting for NetworkStack connector", null);
	return null;
	}
	}
	} catch (InterruptedException e) {
	loge("Error waiting for NetworkStack connector", e);
	return null;
	}

	return INetworkStackConnector.Stub.asInterface(connector);
	}

	private void requestConnector(@NonNull NetworkStackCallback request) {
	// TODO: PID check.
	final int caller = Binder.getCallingUid();
	if (caller != Process.SYSTEM_UID && !UserHandle.isSameApp(caller, Process.BLUETOOTH_UID)
	&& !UserHandle.isSameApp(caller, Process.PHONE_UID)) {
	// Don't even attempt to obtain the connector and give a nice error message
	throw new SecurityException(
	"Only the system server should try to bind to the network stack.");
	}

	if (!mNetworkStackStartRequested) {
	// The network stack is not being started in this process, e.g. this process is not
	// the system server. Get a remote connector registered by the system server.
	final INetworkStackConnector connector = getRemoteConnector();
	synchronized (mPendingNetStackRequests) {
	mConnector = connector;
	}
	request.onNetworkStackConnected(connector);
	return;
	}

	final INetworkStackConnector connector;
	synchronized (mPendingNetStackRequests) {
	connector = mConnector;
	if (connector == null) {
	mPendingNetStackRequests.add(request);
	return;
	}
	}

	request.onNetworkStackConnected(connector);
	}

	/**
	* Dump NetworkStackClient logs to the specified {@link PrintWriter}.
	*/
	public void dump(PrintWriter pw) {
	// dump is thread-safe on SharedLog
	mLog.dump(null, pw, null);

	final int requestsQueueLength;
	synchronized (mPendingNetStackRequests) {
	requestsQueueLength = mPendingNetStackRequests.size();
	}

	pw.println();
	pw.println("pendingNetStackRequests length: " + requestsQueueLength);
	}
	}