package com.android.server.connectivity;
-import java.net.Inet4Address;
-
import android.net.InterfaceConfiguration;
import android.net.ConnectivityManager;
import android.net.LinkAddress;
import com.android.server.net.BaseNetworkObserver;
import com.android.internal.util.ArrayUtils;
+import java.net.Inet4Address;
+import java.util.Objects;
+
/**
* Class to manage a 464xlat CLAT daemon.
*
// The network we're running on, and its type.
private final NetworkAgentInfo mNetwork;
- // Internal state variables.
- //
- // The possible states are:
- // - Idle: start() not called. Everything is null.
- // - Starting: start() called. Interfaces are non-null. isStarted() returns true.
- // mIsRunning is false.
- // - Running: start() called, and interfaceLinkStateChanged() told us that mIface is up.
- // mIsRunning is true.
- //
+ private enum State {
+ IDLE, // start() not called. Base iface and stacked iface names are null.
+ STARTING, // start() called. Base iface and stacked iface names are known.
+ RUNNING; // start() called, and the stacked iface is known to be up.
+ }
+
// Once mIface is non-null and isStarted() is true, methods called by ConnectivityService on
// its handler thread must not modify any internal state variables; they are only updated by the
// interface observers, called on the notification threads.
private String mBaseIface;
private String mIface;
- private boolean mIsRunning;
+ private volatile State mState = State.IDLE;
public Nat464Xlat(INetworkManagementService nmService, Handler handler, NetworkAgentInfo nai) {
mNMService = nmService;
}
/**
- * Determines whether clatd is started. Always true, except a) if start has not yet been called,
- * or b) if our interface was removed.
+ * @return true if clatd has been started and has not yet stopped.
+ * A true result corresponds to internal states STARTING and RUNNING.
*/
public boolean isStarted() {
- return mIface != null;
+ return mState != State.IDLE;
+ }
+
+ /**
+ * @return true if clatd has been started and the stacked interface is up.
+ */
+ public boolean isRunning() {
+ return mState == State.RUNNING;
+ }
+
+ /**
+ * Sets internal state.
+ */
+ private void enterStartingState(String baseIface) {
+ mIface = CLAT_PREFIX + baseIface;
+ mBaseIface = baseIface;
+ mState = State.STARTING;
}
/**
* Clears internal state. Must not be called by ConnectivityService.
*/
- private void clear() {
+ private void enterIdleState() {
mIface = null;
mBaseIface = null;
- mIsRunning = false;
+ mState = State.IDLE;
}
/**
return;
}
- mBaseIface = mNetwork.linkProperties.getInterfaceName();
- if (mBaseIface == null) {
+ String baseIface = mNetwork.linkProperties.getInterfaceName();
+ if (baseIface == null) {
Slog.e(TAG, "startClat: Can't start clat on null interface");
return;
}
- mIface = CLAT_PREFIX + mBaseIface;
- // From now on, isStarted() will return true.
+ // TODO: should we only do this if mNMService.startClatd() succeeds?
+ enterStartingState(baseIface);
Slog.i(TAG, "Starting clatd on " + mBaseIface);
try {
mNMService.startClatd(mBaseIface);
} catch(RemoteException|IllegalStateException e) {
- Slog.e(TAG, "Error starting clatd: " + e);
+ Slog.e(TAG, "Error starting clatd on " + mBaseIface, e);
}
}
* Stops the clat daemon. Called by ConnectivityService on the handler thread.
*/
public void stop() {
- if (isStarted()) {
- Slog.i(TAG, "Stopping clatd");
- try {
- mNMService.stopClatd(mBaseIface);
- } catch(RemoteException|IllegalStateException e) {
- Slog.e(TAG, "Error stopping clatd: " + e);
- }
- // When clatd stops and its interface is deleted, interfaceRemoved() will notify
- // ConnectivityService and call clear().
- } else {
- Slog.e(TAG, "clatd: already stopped");
+ if (!isStarted()) {
+ Slog.e(TAG, "stopClat: already stopped or not started");
+ return;
+ }
+
+ Slog.i(TAG, "Stopping clatd on " + mBaseIface);
+ try {
+ mNMService.stopClatd(mBaseIface);
+ } catch(RemoteException|IllegalStateException e) {
+ Slog.e(TAG, "Error stopping clatd on " + mBaseIface, e);
}
+ // When clatd stops and its interface is deleted, interfaceRemoved() will notify
+ // ConnectivityService and call enterIdleState().
}
private void updateConnectivityService(LinkProperties lp) {
* has no idea that 464xlat is running on top of it.
*/
public void fixupLinkProperties(LinkProperties oldLp) {
- if (mNetwork.clatd != null &&
- mIsRunning &&
- mNetwork.linkProperties != null &&
- !mNetwork.linkProperties.getAllInterfaceNames().contains(mIface)) {
- Slog.d(TAG, "clatd running, updating NAI for " + mIface);
- for (LinkProperties stacked: oldLp.getStackedLinks()) {
- if (mIface.equals(stacked.getInterfaceName())) {
- mNetwork.linkProperties.addStackedLink(stacked);
- break;
- }
+ if (!isRunning()) {
+ return;
+ }
+ LinkProperties lp = mNetwork.linkProperties;
+ if (lp == null || lp.getAllInterfaceNames().contains(mIface)) {
+ return;
+ }
+
+ Slog.d(TAG, "clatd running, updating NAI for " + mIface);
+ for (LinkProperties stacked: oldLp.getStackedLinks()) {
+ if (Objects.equals(mIface, stacked.getInterfaceName())) {
+ lp.addStackedLink(stacked);
+ return;
}
}
}
}
}
+ /**
+ * Adds stacked link on base link and transitions to Running state
+ * This is called by the InterfaceObserver on its own thread, so can race with stop().
+ */
@Override
public void interfaceLinkStateChanged(String iface, boolean up) {
- // Called by the InterfaceObserver on its own thread, so can race with stop().
- if (isStarted() && up && mIface.equals(iface)) {
- Slog.i(TAG, "interface " + iface + " is up, mIsRunning " + mIsRunning + "->true");
-
- if (!mIsRunning) {
- LinkAddress clatAddress = getLinkAddress(iface);
- if (clatAddress == null) {
- return;
- }
- mIsRunning = true;
- maybeSetIpv6NdOffload(mBaseIface, false);
- LinkProperties lp = new LinkProperties(mNetwork.linkProperties);
- lp.addStackedLink(makeLinkProperties(clatAddress));
- Slog.i(TAG, "Adding stacked link " + mIface + " on top of " + mBaseIface);
- updateConnectivityService(lp);
- }
+ if (!isStarted() || !up || !Objects.equals(mIface, iface)) {
+ return;
+ }
+ if (isRunning()) {
+ return;
+ }
+ LinkAddress clatAddress = getLinkAddress(iface);
+ if (clatAddress == null) {
+ return;
}
+ mState = State.RUNNING;
+ Slog.i(TAG, String.format("interface %s is up, adding stacked link %s on top of %s",
+ mIface, mIface, mBaseIface));
+
+ maybeSetIpv6NdOffload(mBaseIface, false);
+ LinkProperties lp = new LinkProperties(mNetwork.linkProperties);
+ lp.addStackedLink(makeLinkProperties(clatAddress));
+ updateConnectivityService(lp);
}
@Override
public void interfaceRemoved(String iface) {
- if (isStarted() && mIface.equals(iface)) {
- Slog.i(TAG, "interface " + iface + " removed, mIsRunning " + mIsRunning + "->false");
-
- if (mIsRunning) {
- // The interface going away likely means clatd has crashed. Ask netd to stop it,
- // because otherwise when we try to start it again on the same base interface netd
- // will complain that it's already started.
- //
- // Note that this method can be called by the interface observer at the same time
- // that ConnectivityService calls stop(). In this case, the second call to
- // stopClatd() will just throw IllegalStateException, which we'll ignore.
- try {
- mNMService.unregisterObserver(this);
- mNMService.stopClatd(mBaseIface);
- } catch (RemoteException|IllegalStateException e) {
- // Well, we tried.
- }
- maybeSetIpv6NdOffload(mBaseIface, true);
- LinkProperties lp = new LinkProperties(mNetwork.linkProperties);
- lp.removeStackedLink(mIface);
- clear();
- updateConnectivityService(lp);
- }
+ if (!isStarted() || !Objects.equals(mIface, iface)) {
+ return;
+ }
+ if (!isRunning()) {
+ return;
+ }
+
+ Slog.i(TAG, "interface " + iface + " removed");
+ // The interface going away likely means clatd has crashed. Ask netd to stop it,
+ // because otherwise when we try to start it again on the same base interface netd
+ // will complain that it's already started.
+ //
+ // Note that this method can be called by the interface observer at the same time
+ // that ConnectivityService calls stop(). In this case, the second call to
+ // stopClatd() will just throw IllegalStateException, which we'll ignore.
+ try {
+ mNMService.unregisterObserver(this);
+ mNMService.stopClatd(mBaseIface);
+ } catch (RemoteException|IllegalStateException e) {
+ // Well, we tried.
}
+ maybeSetIpv6NdOffload(mBaseIface, true);
+ LinkProperties lp = new LinkProperties(mNetwork.linkProperties);
+ lp.removeStackedLink(mIface);
+ enterIdleState();
+ updateConnectivityService(lp);
}
@Override
public String toString() {
- return "mBaseIface: " + mBaseIface + ", mIface: " + mIface + ", mIsRunning: " + mIsRunning;
+ return "mBaseIface: " + mBaseIface + ", mIface: " + mIface + ", mState: " + mState;
}
}
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