services/core/java/com/android/server/connectivity/Nat464Xlat.java - platform/packages/modules/Connectivity - Git at Google

 /*
  * Copyright (C) 2012 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;

 import static android.net.ConnectivityManager.TYPE_MOBILE;

 import java.net.Inet4Address;

 import android.content.Context;
 import android.net.IConnectivityManager;
 import android.net.InterfaceConfiguration;
 import android.net.LinkAddress;
 import android.net.LinkProperties;
 import android.net.NetworkAgent;
 import android.net.NetworkUtils;
 import android.net.RouteInfo;
 import android.os.Handler;
 import android.os.Message;
 import android.os.Messenger;
 import android.os.INetworkManagementService;
 import android.os.RemoteException;
 import android.util.Slog;

 import com.android.server.net.BaseNetworkObserver;

 /**
  * @hide
  *
  * Class to manage a 464xlat CLAT daemon.
  */
 public class Nat464Xlat extends BaseNetworkObserver {
     private Context mContext;
     private INetworkManagementService mNMService;
     private IConnectivityManager mConnService;
     // Whether we started clatd and expect it to be running.
     private boolean mIsStarted;
     // Whether the clatd interface exists (i.e., clatd is running).
     private boolean mIsRunning;
     // The LinkProperties of the clat interface.
     private LinkProperties mLP;
     // Current LinkProperties of the network.  Includes mLP as a stacked link when clat is active.
     private LinkProperties mBaseLP;
     // ConnectivityService Handler for LinkProperties updates.
     private Handler mHandler;
     // Marker to connote which network we're augmenting.
     private Messenger mNetworkMessenger;

     // This must match the interface name in clatd.conf.
     private static final String CLAT_INTERFACE_NAME = "clat4";

     private static final String TAG = "Nat464Xlat";

     public Nat464Xlat(Context context, INetworkManagementService nmService,
                       IConnectivityManager connService, Handler handler) {
         mContext = context;
         mNMService = nmService;
         mConnService = connService;
         mHandler = handler;

         mIsStarted = false;
         mIsRunning = false;
         mLP = new LinkProperties();

         // If this is a runtime restart, it's possible that clatd is already
         // running, but we don't know about it. If so, stop it.
         try {
             if (mNMService.isClatdStarted()) {
                 mNMService.stopClatd();
             }
         } catch(RemoteException e) {}  // Well, we tried.
     }

     /**
      * Determines whether a network requires clat.
      * @param network the NetworkAgentInfo corresponding to the network.
      * @return true if the network requires clat, false otherwise.
      */
     public static boolean requiresClat(NetworkAgentInfo nai) {
         final int netType = nai.networkInfo.getType();
         final boolean connected = nai.networkInfo.isConnected();
         final boolean hasIPv4Address =
                 (nai.linkProperties != null) ? nai.linkProperties.hasIPv4Address() : false;
         Slog.d(TAG, "requiresClat: netType=" + netType +
                     ", connected=" + connected +
                     ", hasIPv4Address=" + hasIPv4Address);
         // Only support clat on mobile for now.
         return netType == TYPE_MOBILE && connected && !hasIPv4Address;
     }

     public boolean isRunningClat(NetworkAgentInfo network) {
         return mNetworkMessenger == network.messenger;
     }

     /**
      * Starts the clat daemon.
      * @param lp The link properties of the interface to start clatd on.
      */
     public void startClat(NetworkAgentInfo network) {
         if (mNetworkMessenger != null && mNetworkMessenger != network.messenger) {
             Slog.e(TAG, "startClat: too many networks requesting clat");
             return;
         }
         mNetworkMessenger = network.messenger;
         LinkProperties lp = network.linkProperties;
         mBaseLP = new LinkProperties(lp);
         if (mIsStarted) {
             Slog.e(TAG, "startClat: already started");
             return;
         }
         String iface = lp.getInterfaceName();
         Slog.i(TAG, "Starting clatd on " + iface + ", lp=" + lp);
         try {
             mNMService.startClatd(iface);
         } catch(RemoteException e) {
             Slog.e(TAG, "Error starting clat daemon: " + e);
         }
         mIsStarted = true;
     }

     /**
      * Stops the clat daemon.
      */
     public void stopClat() {
         if (mIsStarted) {
             Slog.i(TAG, "Stopping clatd");
             try {
                 mNMService.stopClatd();
             } catch(RemoteException e) {
                 Slog.e(TAG, "Error stopping clat daemon: " + e);
             }
             mIsStarted = false;
             mIsRunning = false;
             mNetworkMessenger = null;
             mBaseLP = null;
             mLP.clear();
         } else {
             Slog.e(TAG, "stopClat: already stopped");
         }
     }

     private void updateConnectivityService() {
         Message msg = mHandler.obtainMessage(
             NetworkAgent.EVENT_NETWORK_PROPERTIES_CHANGED, mBaseLP);
         msg.replyTo = mNetworkMessenger;
         Slog.i(TAG, "sending message to ConnectivityService: " + msg);
         msg.sendToTarget();
     }

     // Copies the stacked clat link in oldLp, if any, to the LinkProperties in nai.
     public void fixupLinkProperties(NetworkAgentInfo nai, LinkProperties oldLp) {
         if (isRunningClat(nai) &&
                 nai.linkProperties != null &&
                 !nai.linkProperties.getAllInterfaceNames().contains(CLAT_INTERFACE_NAME)) {
             Slog.d(TAG, "clatd running, updating NAI for " + nai.linkProperties.getInterfaceName());
             for (LinkProperties stacked: oldLp.getStackedLinks()) {
                 if (CLAT_INTERFACE_NAME.equals(stacked.getInterfaceName())) {
                     nai.linkProperties.addStackedLink(stacked);
                     break;
                 }
             }
         }
     }

     @Override
     public void interfaceAdded(String iface) {
         if (iface.equals(CLAT_INTERFACE_NAME)) {
             Slog.i(TAG, "interface " + CLAT_INTERFACE_NAME +
                    " added, mIsRunning = " + mIsRunning + " -> true");
             mIsRunning = true;

             // Create the LinkProperties for the clat interface by fetching the
             // IPv4 address for the interface and adding an IPv4 default route,
             // then stack the LinkProperties on top of the link it's running on.
             try {
                 InterfaceConfiguration config = mNMService.getInterfaceConfig(iface);
                 LinkAddress clatAddress = config.getLinkAddress();
                 mLP.clear();
                 mLP.setInterfaceName(iface);

                 // Although the clat interface is a point-to-point tunnel, we don't
                 // point the route directly at the interface because some apps don't
                 // understand routes without gateways (see, e.g., http://b/9597256
                 // http://b/9597516). Instead, set the next hop of the route to the
                 // clat IPv4 address itself (for those apps, it doesn't matter what
                 // the IP of the gateway is, only that there is one).
                 RouteInfo ipv4Default = new RouteInfo(new LinkAddress(Inet4Address.ANY, 0),
                                                       clatAddress.getAddress(), iface);
                 mLP.addRoute(ipv4Default);
                 mLP.addLinkAddress(clatAddress);
                 mBaseLP.addStackedLink(mLP);
                 Slog.i(TAG, "Adding stacked link. tracker LP: " + mBaseLP);
                 updateConnectivityService();
             } catch(RemoteException e) {
                 Slog.e(TAG, "Error getting link properties: " + e);
             }
         }
     }

     @Override
     public void interfaceRemoved(String iface) {
         if (iface == CLAT_INTERFACE_NAME) {
             if (mIsRunning) {
                 NetworkUtils.resetConnections(
                     CLAT_INTERFACE_NAME,
                     NetworkUtils.RESET_IPV4_ADDRESSES);
                 mBaseLP.removeStackedLink(mLP);
                 updateConnectivityService();
             }
             Slog.i(TAG, "interface " + CLAT_INTERFACE_NAME +
                    " removed, mIsRunning = " + mIsRunning + " -> false");
             mIsRunning = false;
             mLP.clear();
             Slog.i(TAG, "mLP = " + mLP);
         }
     }
 };
	/*
	* Copyright (C) 2012 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;

	import static android.net.ConnectivityManager.TYPE_MOBILE;

	import java.net.Inet4Address;

	import android.content.Context;
	import android.net.IConnectivityManager;
	import android.net.InterfaceConfiguration;
	import android.net.LinkAddress;
	import android.net.LinkProperties;
	import android.net.NetworkAgent;
	import android.net.NetworkUtils;
	import android.net.RouteInfo;
	import android.os.Handler;
	import android.os.Message;
	import android.os.Messenger;
	import android.os.INetworkManagementService;
	import android.os.RemoteException;
	import android.util.Slog;

	import com.android.server.net.BaseNetworkObserver;

	/**
	* @hide
	*
	* Class to manage a 464xlat CLAT daemon.
	*/
	public class Nat464Xlat extends BaseNetworkObserver {
	private Context mContext;
	private INetworkManagementService mNMService;
	private IConnectivityManager mConnService;
	// Whether we started clatd and expect it to be running.
	private boolean mIsStarted;
	// Whether the clatd interface exists (i.e., clatd is running).
	private boolean mIsRunning;
	// The LinkProperties of the clat interface.
	private LinkProperties mLP;
	// Current LinkProperties of the network. Includes mLP as a stacked link when clat is active.
	private LinkProperties mBaseLP;
	// ConnectivityService Handler for LinkProperties updates.
	private Handler mHandler;
	// Marker to connote which network we're augmenting.
	private Messenger mNetworkMessenger;

	// This must match the interface name in clatd.conf.
	private static final String CLAT_INTERFACE_NAME = "clat4";

	private static final String TAG = "Nat464Xlat";

	public Nat464Xlat(Context context, INetworkManagementService nmService,
	IConnectivityManager connService, Handler handler) {
	mContext = context;
	mNMService = nmService;
	mConnService = connService;
	mHandler = handler;

	mIsStarted = false;
	mIsRunning = false;
	mLP = new LinkProperties();

	// If this is a runtime restart, it's possible that clatd is already
	// running, but we don't know about it. If so, stop it.
	try {
	if (mNMService.isClatdStarted()) {
	mNMService.stopClatd();
	}
	} catch(RemoteException e) {} // Well, we tried.
	}

	/**
	* Determines whether a network requires clat.
	* @param network the NetworkAgentInfo corresponding to the network.
	* @return true if the network requires clat, false otherwise.
	*/
	public static boolean requiresClat(NetworkAgentInfo nai) {
	final int netType = nai.networkInfo.getType();
	final boolean connected = nai.networkInfo.isConnected();
	final boolean hasIPv4Address =
	(nai.linkProperties != null) ? nai.linkProperties.hasIPv4Address() : false;
	Slog.d(TAG, "requiresClat: netType=" + netType +
	", connected=" + connected +
	", hasIPv4Address=" + hasIPv4Address);
	// Only support clat on mobile for now.
	return netType == TYPE_MOBILE && connected && !hasIPv4Address;
	}

	public boolean isRunningClat(NetworkAgentInfo network) {
	return mNetworkMessenger == network.messenger;
	}

	/**
	* Starts the clat daemon.
	* @param lp The link properties of the interface to start clatd on.
	*/
	public void startClat(NetworkAgentInfo network) {
	if (mNetworkMessenger != null && mNetworkMessenger != network.messenger) {
	Slog.e(TAG, "startClat: too many networks requesting clat");
	return;
	}
	mNetworkMessenger = network.messenger;
	LinkProperties lp = network.linkProperties;
	mBaseLP = new LinkProperties(lp);
	if (mIsStarted) {
	Slog.e(TAG, "startClat: already started");
	return;
	}
	String iface = lp.getInterfaceName();
	Slog.i(TAG, "Starting clatd on " + iface + ", lp=" + lp);
	try {
	mNMService.startClatd(iface);
	} catch(RemoteException e) {
	Slog.e(TAG, "Error starting clat daemon: " + e);
	}
	mIsStarted = true;
	}

	/**
	* Stops the clat daemon.
	*/
	public void stopClat() {
	if (mIsStarted) {
	Slog.i(TAG, "Stopping clatd");
	try {
	mNMService.stopClatd();
	} catch(RemoteException e) {
	Slog.e(TAG, "Error stopping clat daemon: " + e);
	}
	mIsStarted = false;
	mIsRunning = false;
	mNetworkMessenger = null;
	mBaseLP = null;
	mLP.clear();
	} else {
	Slog.e(TAG, "stopClat: already stopped");
	}
	}

	private void updateConnectivityService() {
	Message msg = mHandler.obtainMessage(
	NetworkAgent.EVENT_NETWORK_PROPERTIES_CHANGED, mBaseLP);
	msg.replyTo = mNetworkMessenger;
	Slog.i(TAG, "sending message to ConnectivityService: " + msg);
	msg.sendToTarget();
	}

	// Copies the stacked clat link in oldLp, if any, to the LinkProperties in nai.
	public void fixupLinkProperties(NetworkAgentInfo nai, LinkProperties oldLp) {
	if (isRunningClat(nai) &&
	nai.linkProperties != null &&
	!nai.linkProperties.getAllInterfaceNames().contains(CLAT_INTERFACE_NAME)) {
	Slog.d(TAG, "clatd running, updating NAI for " + nai.linkProperties.getInterfaceName());
	for (LinkProperties stacked: oldLp.getStackedLinks()) {
	if (CLAT_INTERFACE_NAME.equals(stacked.getInterfaceName())) {
	nai.linkProperties.addStackedLink(stacked);
	break;
	}
	}
	}
	}

	@Override
	public void interfaceAdded(String iface) {
	if (iface.equals(CLAT_INTERFACE_NAME)) {
	Slog.i(TAG, "interface " + CLAT_INTERFACE_NAME +
	" added, mIsRunning = " + mIsRunning + " -> true");
	mIsRunning = true;

	// Create the LinkProperties for the clat interface by fetching the
	// IPv4 address for the interface and adding an IPv4 default route,
	// then stack the LinkProperties on top of the link it's running on.
	try {
	InterfaceConfiguration config = mNMService.getInterfaceConfig(iface);
	LinkAddress clatAddress = config.getLinkAddress();
	mLP.clear();
	mLP.setInterfaceName(iface);

	// Although the clat interface is a point-to-point tunnel, we don't
	// point the route directly at the interface because some apps don't
	// understand routes without gateways (see, e.g., http://b/9597256
	// http://b/9597516). Instead, set the next hop of the route to the
	// clat IPv4 address itself (for those apps, it doesn't matter what
	// the IP of the gateway is, only that there is one).
	RouteInfo ipv4Default = new RouteInfo(new LinkAddress(Inet4Address.ANY, 0),
	clatAddress.getAddress(), iface);
	mLP.addRoute(ipv4Default);
	mLP.addLinkAddress(clatAddress);
	mBaseLP.addStackedLink(mLP);
	Slog.i(TAG, "Adding stacked link. tracker LP: " + mBaseLP);
	updateConnectivityService();
	} catch(RemoteException e) {
	Slog.e(TAG, "Error getting link properties: " + e);
	}
	}
	}

	@Override
	public void interfaceRemoved(String iface) {
	if (iface == CLAT_INTERFACE_NAME) {
	if (mIsRunning) {
	NetworkUtils.resetConnections(
	CLAT_INTERFACE_NAME,
	NetworkUtils.RESET_IPV4_ADDRESSES);
	mBaseLP.removeStackedLink(mLP);
	updateConnectivityService();
	}
	Slog.i(TAG, "interface " + CLAT_INTERFACE_NAME +
	" removed, mIsRunning = " + mIsRunning + " -> false");
	mIsRunning = false;
	mLP.clear();
	Slog.i(TAG, "mLP = " + mLP);
	}
	}
	};