core/java/android/net/NetworkStack.java - platform/frameworks/base - Gitiles

 /*
  * Copyright (C) 2018 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.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.annotation.SystemApi;
 import android.annotation.SystemService;
 import android.annotation.TestApi;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
 import android.content.ServiceConnection;
 import android.net.dhcp.DhcpServingParamsParcel;
 import android.net.dhcp.IDhcpServerCallbacks;
 import android.net.ip.IIpClientCallbacks;
 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.lang.reflect.InvocationTargetException;
 import java.util.ArrayList;

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

     /**
      * Permission granted only to the NetworkStack APK, defined in NetworkStackStub with signature
      * protection level.
      * @hide
      */
     @SystemApi
     @TestApi
     public static final String PERMISSION_MAINLINE_NETWORK_STACK =
             "android.permission.MAINLINE_NETWORK_STACK";

     /** @hide */
     public static final String NETWORKSTACK_PACKAGE_NAME = "com.android.mainline.networkstack";

     private static final int NETWORKSTACK_TIMEOUT_MS = 10_000;

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

     private volatile boolean mNetworkStackStartRequested = false;

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

     /** @hide */
     public NetworkStack() { }

     /**
      * Create a DHCP server according to the specified parameters.
      *
      * <p>The server will be returned asynchronously through the provided callbacks.
      * @hide
      */
     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.
      * @hide
      */
     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.
      * @hide
      */
     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) {
             registerNetworkStackService(service);
         }

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

     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);

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

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

     /**
      * 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.
      * @hide
      */
     public void start(Context context) {
         mNetworkStackStartRequested = true;
         // Try to bind in-process if the library is available
         IBinder connector = null;
         try {
             final Class service = Class.forName(
                     "com.android.server.NetworkStackService",
                     true /* initialize */,
                     context.getClassLoader());
             connector = (IBinder) service.getMethod("makeConnector", Context.class)
                     .invoke(null, context);
         } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
             Slog.wtf(TAG, "Could not create network stack connector from NetworkStackService");
             // TODO: crash/reboot system here ?
             return;
         } catch (ClassNotFoundException e) {
             // Normal behavior if stack is provided by the app: fall through
         }

         // In-process network stack. Add the service to the service manager here.
         if (connector != null) {
             registerNetworkStackService(connector);
             return;
         }
         // Start the network stack process. The service will be added to the service manager in
         // NetworkStackConnection.onServiceConnected().
         final Intent intent = new Intent(INetworkStackConnector.class.getName());
         final ComponentName comp = intent.resolveSystemService(context.getPackageManager(), 0);
         intent.setComponent(comp);

         if (comp == null || !context.bindServiceAsUser(intent, new NetworkStackConnection(),
                 Context.BIND_AUTO_CREATE | Context.BIND_IMPORTANT, UserHandle.SYSTEM)) {
             Slog.wtf(TAG,
                     "Could not bind to network stack in-process, or in app with " + intent);
             // TODO: crash/reboot system server if no network stack after a timeout ?
         }
     }

     /**
      * 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) {
                     Slog.e(TAG, "Timeout waiting for NetworkStack connector");
                     return null;
                 }
             }
         } catch (InterruptedException e) {
             Slog.e(TAG, "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)) {
             // 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);
     }
 }
	/*
	* Copyright (C) 2018 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.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.annotation.SystemApi;
	import android.annotation.SystemService;
	import android.annotation.TestApi;
	import android.content.ComponentName;
	import android.content.Context;
	import android.content.Intent;
	import android.content.ServiceConnection;
	import android.net.dhcp.DhcpServingParamsParcel;
	import android.net.dhcp.IDhcpServerCallbacks;
	import android.net.ip.IIpClientCallbacks;
	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.lang.reflect.InvocationTargetException;
	import java.util.ArrayList;

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

	/**
	* Permission granted only to the NetworkStack APK, defined in NetworkStackStub with signature
	* protection level.
	* @hide
	*/
	@SystemApi
	@TestApi
	public static final String PERMISSION_MAINLINE_NETWORK_STACK =
	"android.permission.MAINLINE_NETWORK_STACK";

	/** @hide */
	public static final String NETWORKSTACK_PACKAGE_NAME = "com.android.mainline.networkstack";

	private static final int NETWORKSTACK_TIMEOUT_MS = 10_000;

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

	private volatile boolean mNetworkStackStartRequested = false;

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

	/** @hide */
	public NetworkStack() { }

	/**
	* Create a DHCP server according to the specified parameters.
	*
	* <p>The server will be returned asynchronously through the provided callbacks.
	* @hide
	*/
	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.
	* @hide
	*/
	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.
	* @hide
	*/
	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) {
	registerNetworkStackService(service);
	}

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

	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);

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

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

	/**
	* 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.
	* @hide
	*/
	public void start(Context context) {
	mNetworkStackStartRequested = true;
	// Try to bind in-process if the library is available
	IBinder connector = null;
	try {
	final Class service = Class.forName(
	"com.android.server.NetworkStackService",
	true /* initialize */,
	context.getClassLoader());
	connector = (IBinder) service.getMethod("makeConnector", Context.class)
	.invoke(null, context);
	} catch (NoSuchMethodException \| IllegalAccessException \| InvocationTargetException e) {
	Slog.wtf(TAG, "Could not create network stack connector from NetworkStackService");
	// TODO: crash/reboot system here ?
	return;
	} catch (ClassNotFoundException e) {
	// Normal behavior if stack is provided by the app: fall through
	}

	// In-process network stack. Add the service to the service manager here.
	if (connector != null) {
	registerNetworkStackService(connector);
	return;
	}
	// Start the network stack process. The service will be added to the service manager in
	// NetworkStackConnection.onServiceConnected().
	final Intent intent = new Intent(INetworkStackConnector.class.getName());
	final ComponentName comp = intent.resolveSystemService(context.getPackageManager(), 0);
	intent.setComponent(comp);

	if (comp == null \|\| !context.bindServiceAsUser(intent, new NetworkStackConnection(),
	Context.BIND_AUTO_CREATE \| Context.BIND_IMPORTANT, UserHandle.SYSTEM)) {
	Slog.wtf(TAG,
	"Could not bind to network stack in-process, or in app with " + intent);
	// TODO: crash/reboot system server if no network stack after a timeout ?
	}
	}

	/**
	* 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) {
	Slog.e(TAG, "Timeout waiting for NetworkStack connector");
	return null;
	}
	}
	} catch (InterruptedException e) {
	Slog.e(TAG, "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)) {
	// 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);
	}
	}