Merge "Refactor the Nat464Xlat function for simplicity." (a941cd53) · Commits · e / os / android_frameworks_base

services/core/java/com/android/server/connectivity/Nat464Xlat.java

+38 −23

Original line number	Diff line number	Diff line
		@@ -213,12 +213,10 @@ public class Nat464Xlat extends BaseNetworkObserver {
		}
		mIface = null;
		mBaseIface = null;
		mState = State.IDLE;
		if (requiresClat(mNetwork)) {
		mState = State.DISCOVERING;
		} else {
		stopPrefixDiscovery();
		mState = State.IDLE;
		}
		}

		@@ -285,6 +283,7 @@ public class Nat464Xlat extends BaseNetworkObserver {
		private void stopPrefixDiscovery() {
		try {
		mDnsResolver.stopPrefix64Discovery(getNetId());
		mState = State.IDLE;
		} catch (RemoteException \| ServiceSpecificException e) {
		Slog.e(TAG, "Error stopping prefix discovery on netId " + getNetId() + ": " + e);
		}
		@@ -294,27 +293,43 @@ public class Nat464Xlat extends BaseNetworkObserver {
		* Starts/stops NAT64 prefix discovery and clatd as necessary.
		*/
		public void update() {
		// TODO: turn this class into a proper StateMachine. // http://b/126113090
		// TODO: turn this class into a proper StateMachine. http://b/126113090
		switch (mState) {
		case IDLE:
		if (requiresClat(mNetwork)) {
		if (!isPrefixDiscoveryStarted()) {
		startPrefixDiscovery();
		} else if (shouldStartClat(mNetwork)) {
		// Network is detected to be IPv6-only.
		// TODO: consider going to STARTING directly if the NAT64 prefix is already
		// known. This would however result in clatd running without prefix discovery
		// running, which might be a surprising combination.
		startPrefixDiscovery(); // Enters DISCOVERING state.
		return;
		}
		break;

		case DISCOVERING:
		if (shouldStartClat(mNetwork)) {
		// NAT64 prefix detected. Start clatd.
		// TODO: support the NAT64 prefix changing after it's been discovered. There is no
		// need to support this at the moment because it cannot happen without changes to
		// the Dns64Configuration code in netd.
		start();
		} else {
		// NAT64 prefix removed. Stop clatd and go back into DISCOVERING state.
		stop();
		start(); // Enters STARTING state.
		return;
		}
		} else {
		// Network no longer requires clat. Stop clat and prefix discovery.
		if (isStarted()) {
		if (!requiresClat(mNetwork)) {
		// IPv4 address added. Go back to IDLE state.
		stopPrefixDiscovery();
		return;
		}
		break;

		case STARTING:
		case RUNNING:
		// NAT64 prefix removed, or IPv4 address added.
		// Stop clatd and go back into DISCOVERING or idle.
		if (!shouldStartClat(mNetwork)) {
		stop();
		} else if (isPrefixDiscoveryStarted()) {
		leaveStartedState();
		}
		break;
		// TODO: support the NAT64 prefix changing after it's been discovered. There is
		// no need to support this at the moment because it cannot happen without
		// changes to the Dns64Configuration code in netd.
		}
		}