/* * 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); } } };