| /* |
| * Copyright (C) 2016 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 android.net.ConnectivityManager; |
| import android.net.INetworkStatsService; |
| import android.net.InterfaceConfiguration; |
| import android.net.LinkAddress; |
| import android.net.LinkProperties; |
| import android.net.NetworkUtils; |
| import android.os.INetworkManagementService; |
| import android.os.Looper; |
| import android.os.Message; |
| import android.util.Log; |
| import android.util.SparseArray; |
| |
| import com.android.internal.util.MessageUtils; |
| import com.android.internal.util.Protocol; |
| import com.android.internal.util.State; |
| import com.android.internal.util.StateMachine; |
| |
| import java.net.InetAddress; |
| |
| /** |
| * @hide |
| * |
| * Tracks the eligibility of a given network interface for tethering. |
| */ |
| public class TetherInterfaceStateMachine extends StateMachine { |
| private static final String USB_NEAR_IFACE_ADDR = "192.168.42.129"; |
| private static final int USB_PREFIX_LENGTH = 24; |
| private static final String WIFI_HOST_IFACE_ADDR = "192.168.43.1"; |
| private static final int WIFI_HOST_IFACE_PREFIX_LENGTH = 24; |
| |
| private final static String TAG = "TetherInterfaceSM"; |
| private final static boolean DBG = false; |
| private final static boolean VDBG = false; |
| private static final Class[] messageClasses = { |
| TetherInterfaceStateMachine.class |
| }; |
| private static final SparseArray<String> sMagicDecoderRing = |
| MessageUtils.findMessageNames(messageClasses); |
| |
| private static final int BASE_IFACE = Protocol.BASE_TETHERING + 100; |
| // request from the user that it wants to tether |
| public static final int CMD_TETHER_REQUESTED = BASE_IFACE + 2; |
| // request from the user that it wants to untether |
| public static final int CMD_TETHER_UNREQUESTED = BASE_IFACE + 3; |
| // notification that this interface is down |
| public static final int CMD_INTERFACE_DOWN = BASE_IFACE + 4; |
| // notification from the master SM that it had trouble enabling IP Forwarding |
| public static final int CMD_IP_FORWARDING_ENABLE_ERROR = BASE_IFACE + 7; |
| // notification from the master SM that it had trouble disabling IP Forwarding |
| public static final int CMD_IP_FORWARDING_DISABLE_ERROR = BASE_IFACE + 8; |
| // notification from the master SM that it had trouble starting tethering |
| public static final int CMD_START_TETHERING_ERROR = BASE_IFACE + 9; |
| // notification from the master SM that it had trouble stopping tethering |
| public static final int CMD_STOP_TETHERING_ERROR = BASE_IFACE + 10; |
| // notification from the master SM that it had trouble setting the DNS forwarders |
| public static final int CMD_SET_DNS_FORWARDERS_ERROR = BASE_IFACE + 11; |
| // the upstream connection has changed |
| public static final int CMD_TETHER_CONNECTION_CHANGED = BASE_IFACE + 12; |
| // new IPv6 tethering parameters need to be processed |
| public static final int CMD_IPV6_TETHER_UPDATE = BASE_IFACE + 13; |
| |
| private final State mInitialState; |
| private final State mTetheredState; |
| private final State mUnavailableState; |
| |
| private final INetworkManagementService mNMService; |
| private final INetworkStatsService mStatsService; |
| private final IControlsTethering mTetherController; |
| |
| private final String mIfaceName; |
| private final int mInterfaceType; |
| private final IPv6TetheringInterfaceServices mIPv6TetherSvc; |
| |
| private int mLastError; |
| private String mMyUpstreamIfaceName; // may change over time |
| |
| public TetherInterfaceStateMachine(String ifaceName, Looper looper, int interfaceType, |
| INetworkManagementService nMService, INetworkStatsService statsService, |
| IControlsTethering tetherController, IPv6TetheringInterfaceServices ipv6Svc) { |
| super(ifaceName, looper); |
| mNMService = nMService; |
| mStatsService = statsService; |
| mTetherController = tetherController; |
| mIfaceName = ifaceName; |
| mInterfaceType = interfaceType; |
| mIPv6TetherSvc = ipv6Svc; |
| mLastError = ConnectivityManager.TETHER_ERROR_NO_ERROR; |
| |
| mInitialState = new InitialState(); |
| addState(mInitialState); |
| mTetheredState = new TetheredState(); |
| addState(mTetheredState); |
| mUnavailableState = new UnavailableState(); |
| addState(mUnavailableState); |
| |
| setInitialState(mInitialState); |
| } |
| |
| public int interfaceType() { |
| return mInterfaceType; |
| } |
| |
| // configured when we start tethering and unconfig'd on error or conclusion |
| private boolean configureIfaceIp(boolean enabled) { |
| if (VDBG) Log.d(TAG, "configureIfaceIp(" + enabled + ")"); |
| |
| String ipAsString = null; |
| int prefixLen = 0; |
| if (mInterfaceType == ConnectivityManager.TETHERING_USB) { |
| ipAsString = USB_NEAR_IFACE_ADDR; |
| prefixLen = USB_PREFIX_LENGTH; |
| } else if (mInterfaceType == ConnectivityManager.TETHERING_WIFI) { |
| ipAsString = WIFI_HOST_IFACE_ADDR; |
| prefixLen = WIFI_HOST_IFACE_PREFIX_LENGTH; |
| } else { |
| // Nothing to do, BT does this elsewhere. |
| return true; |
| } |
| |
| InterfaceConfiguration ifcg = null; |
| try { |
| ifcg = mNMService.getInterfaceConfig(mIfaceName); |
| if (ifcg != null) { |
| InetAddress addr = NetworkUtils.numericToInetAddress(ipAsString); |
| ifcg.setLinkAddress(new LinkAddress(addr, prefixLen)); |
| if (mInterfaceType == ConnectivityManager.TETHERING_WIFI) { |
| // The WiFi stack has ownership of the interface up/down state. |
| // It is unclear whether the bluetooth or USB stacks will manage their own |
| // state. |
| ifcg.ignoreInterfaceUpDownStatus(); |
| } else { |
| if (enabled) { |
| ifcg.setInterfaceUp(); |
| } else { |
| ifcg.setInterfaceDown(); |
| } |
| } |
| ifcg.clearFlag("running"); |
| mNMService.setInterfaceConfig(mIfaceName, ifcg); |
| } |
| } catch (Exception e) { |
| Log.e(TAG, "Error configuring interface " + mIfaceName, e); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| private void maybeLogMessage(State state, int what) { |
| if (DBG) { |
| Log.d(TAG, state.getName() + " got " + |
| sMagicDecoderRing.get(what, Integer.toString(what))); |
| } |
| } |
| |
| class InitialState extends State { |
| @Override |
| public void enter() { |
| mTetherController.notifyInterfaceStateChange( |
| mIfaceName, TetherInterfaceStateMachine.this, |
| IControlsTethering.STATE_AVAILABLE, mLastError); |
| } |
| |
| @Override |
| public boolean processMessage(Message message) { |
| maybeLogMessage(this, message.what); |
| boolean retValue = true; |
| switch (message.what) { |
| case CMD_TETHER_REQUESTED: |
| mLastError = ConnectivityManager.TETHER_ERROR_NO_ERROR; |
| transitionTo(mTetheredState); |
| break; |
| case CMD_INTERFACE_DOWN: |
| transitionTo(mUnavailableState); |
| break; |
| case CMD_IPV6_TETHER_UPDATE: |
| mIPv6TetherSvc.updateUpstreamIPv6LinkProperties( |
| (LinkProperties) message.obj); |
| break; |
| default: |
| retValue = false; |
| break; |
| } |
| return retValue; |
| } |
| } |
| |
| class TetheredState extends State { |
| @Override |
| public void enter() { |
| if (!configureIfaceIp(true)) { |
| mLastError = ConnectivityManager.TETHER_ERROR_IFACE_CFG_ERROR; |
| transitionTo(mInitialState); |
| return; |
| } |
| |
| try { |
| mNMService.tetherInterface(mIfaceName); |
| } catch (Exception e) { |
| Log.e(TAG, "Error Tethering: " + e.toString()); |
| mLastError = ConnectivityManager.TETHER_ERROR_TETHER_IFACE_ERROR; |
| transitionTo(mInitialState); |
| return; |
| } |
| |
| if (!mIPv6TetherSvc.start()) { |
| Log.e(TAG, "Failed to start IPv6TetheringInterfaceServices"); |
| } |
| |
| if (DBG) Log.d(TAG, "Tethered " + mIfaceName); |
| mTetherController.notifyInterfaceStateChange( |
| mIfaceName, TetherInterfaceStateMachine.this, |
| IControlsTethering.STATE_TETHERED, mLastError); |
| } |
| |
| @Override |
| public void exit() { |
| // Note that at this point, we're leaving the tethered state. We can fail any |
| // of these operations, but it doesn't really change that we have to try them |
| // all in sequence. |
| mIPv6TetherSvc.stop(); |
| cleanupUpstream(); |
| |
| try { |
| mNMService.untetherInterface(mIfaceName); |
| } catch (Exception ee) { |
| mLastError = ConnectivityManager.TETHER_ERROR_UNTETHER_IFACE_ERROR; |
| Log.e(TAG, "Failed to untether interface: " + ee.toString()); |
| } |
| |
| configureIfaceIp(false); |
| } |
| |
| private void cleanupUpstream() { |
| if (mMyUpstreamIfaceName != null) { |
| // note that we don't care about errors here. |
| // sometimes interfaces are gone before we get |
| // to remove their rules, which generates errors. |
| // just do the best we can. |
| try { |
| // about to tear down NAT; gather remaining statistics |
| mStatsService.forceUpdate(); |
| } catch (Exception e) { |
| if (VDBG) Log.e(TAG, "Exception in forceUpdate: " + e.toString()); |
| } |
| try { |
| mNMService.stopInterfaceForwarding(mIfaceName, mMyUpstreamIfaceName); |
| } catch (Exception e) { |
| if (VDBG) Log.e( |
| TAG, "Exception in removeInterfaceForward: " + e.toString()); |
| } |
| try { |
| mNMService.disableNat(mIfaceName, mMyUpstreamIfaceName); |
| } catch (Exception e) { |
| if (VDBG) Log.e(TAG, "Exception in disableNat: " + e.toString()); |
| } |
| mMyUpstreamIfaceName = null; |
| } |
| return; |
| } |
| |
| @Override |
| public boolean processMessage(Message message) { |
| maybeLogMessage(this, message.what); |
| boolean retValue = true; |
| switch (message.what) { |
| case CMD_TETHER_UNREQUESTED: |
| transitionTo(mInitialState); |
| if (DBG) Log.d(TAG, "Untethered (unrequested)" + mIfaceName); |
| break; |
| case CMD_INTERFACE_DOWN: |
| transitionTo(mUnavailableState); |
| if (DBG) Log.d(TAG, "Untethered (ifdown)" + mIfaceName); |
| break; |
| case CMD_TETHER_CONNECTION_CHANGED: |
| String newUpstreamIfaceName = (String)(message.obj); |
| if ((mMyUpstreamIfaceName == null && newUpstreamIfaceName == null) || |
| (mMyUpstreamIfaceName != null && |
| mMyUpstreamIfaceName.equals(newUpstreamIfaceName))) { |
| if (VDBG) Log.d(TAG, "Connection changed noop - dropping"); |
| break; |
| } |
| cleanupUpstream(); |
| if (newUpstreamIfaceName != null) { |
| try { |
| mNMService.enableNat(mIfaceName, newUpstreamIfaceName); |
| mNMService.startInterfaceForwarding(mIfaceName, |
| newUpstreamIfaceName); |
| } catch (Exception e) { |
| Log.e(TAG, "Exception enabling Nat: " + e.toString()); |
| mLastError = ConnectivityManager.TETHER_ERROR_ENABLE_NAT_ERROR; |
| transitionTo(mInitialState); |
| return true; |
| } |
| } |
| mMyUpstreamIfaceName = newUpstreamIfaceName; |
| break; |
| case CMD_IPV6_TETHER_UPDATE: |
| mIPv6TetherSvc.updateUpstreamIPv6LinkProperties( |
| (LinkProperties) message.obj); |
| break; |
| case CMD_IP_FORWARDING_ENABLE_ERROR: |
| case CMD_IP_FORWARDING_DISABLE_ERROR: |
| case CMD_START_TETHERING_ERROR: |
| case CMD_STOP_TETHERING_ERROR: |
| case CMD_SET_DNS_FORWARDERS_ERROR: |
| mLastError = ConnectivityManager.TETHER_ERROR_MASTER_ERROR; |
| transitionTo(mInitialState); |
| break; |
| default: |
| retValue = false; |
| break; |
| } |
| return retValue; |
| } |
| } |
| |
| /** |
| * This state is terminal for the per interface state machine. At this |
| * point, the master state machine should have removed this interface |
| * specific state machine from its list of possible recipients of |
| * tethering requests. The state machine itself will hang around until |
| * the garbage collector finds it. |
| */ |
| class UnavailableState extends State { |
| @Override |
| public void enter() { |
| mLastError = ConnectivityManager.TETHER_ERROR_NO_ERROR; |
| mTetherController.notifyInterfaceStateChange( |
| mIfaceName, TetherInterfaceStateMachine.this, |
| IControlsTethering.STATE_UNAVAILABLE, mLastError); |
| } |
| } |
| } |