VCN: Handle sequence number leap in packet loss detector (6bc811da) · Commits · e / os / android_frameworks_base

core/java/android/net/vcn/VcnManager.java

+17 −0

Original line number	Original line	Diff line number	Diff line
	@@ -123,6 +123,22 @@ public class VcnManager {
	public static final String VCN_NETWORK_SELECTION_IPSEC_PACKET_LOSS_PERCENT_THRESHOLD_KEY =		public static final String VCN_NETWORK_SELECTION_IPSEC_PACKET_LOSS_PERCENT_THRESHOLD_KEY =
	"vcn_network_selection_ipsec_packet_loss_percent_threshold";		"vcn_network_selection_ipsec_packet_loss_percent_threshold";

			/**
			* Key for detecting unusually large increases in IPsec packet sequence numbers.
			*
			* <p>If the sequence number increases by more than this value within a second, it may indicate
			* an intentional leap on the server's downlink. To avoid false positives, the packet loss
			* detector will suppress loss reporting.
			*
			* <p>By default, there's no maximum limit enforced, prioritizing detection of lossy networks.
			* To reduce false positives, consider setting an appropriate maximum threshold.
			*
			* @hide
			*/
			@NonNull
			public static final String VCN_NETWORK_SELECTION_MAX_SEQ_NUM_INCREASE_PER_SECOND_KEY =
			"vcn_network_selection_max_seq_num_increase_per_second";

	/**		/**
	* Key for the list of timeouts in minute to stop penalizing an underlying network candidate		* Key for the list of timeouts in minute to stop penalizing an underlying network candidate
	*		*
	@@ -180,6 +196,7 @@ public class VcnManager {
	VCN_NETWORK_SELECTION_WIFI_EXIT_RSSI_THRESHOLD_KEY,		VCN_NETWORK_SELECTION_WIFI_EXIT_RSSI_THRESHOLD_KEY,
	VCN_NETWORK_SELECTION_POLL_IPSEC_STATE_INTERVAL_SECONDS_KEY,		VCN_NETWORK_SELECTION_POLL_IPSEC_STATE_INTERVAL_SECONDS_KEY,
	VCN_NETWORK_SELECTION_IPSEC_PACKET_LOSS_PERCENT_THRESHOLD_KEY,		VCN_NETWORK_SELECTION_IPSEC_PACKET_LOSS_PERCENT_THRESHOLD_KEY,
			VCN_NETWORK_SELECTION_MAX_SEQ_NUM_INCREASE_PER_SECOND_KEY,
	VCN_NETWORK_SELECTION_PENALTY_TIMEOUT_MINUTES_LIST_KEY,		VCN_NETWORK_SELECTION_PENALTY_TIMEOUT_MINUTES_LIST_KEY,
	VCN_RESTRICTED_TRANSPORTS_INT_ARRAY_KEY,		VCN_RESTRICTED_TRANSPORTS_INT_ARRAY_KEY,
	VCN_SAFE_MODE_TIMEOUT_SECONDS_KEY,		VCN_SAFE_MODE_TIMEOUT_SECONDS_KEY,

core/java/android/net/vcn/flags.aconfig

+10 −0

Original line number	Original line	Diff line number	Diff line
	@@ -35,3 +35,13 @@ flag{
	description: "Re-evaluate IPsec packet loss on LinkProperties or NetworkCapabilities change"		description: "Re-evaluate IPsec packet loss on LinkProperties or NetworkCapabilities change"
	bug: "323238888"		bug: "323238888"
	}		}

			flag{
			name: "handle_seq_num_leap"
			namespace: "vcn"
			description: "Do not report bad network when there is a suspected sequence number leap"
			bug: "332598276"
			metadata {
			purpose: PURPOSE_BUGFIX
			}
			}
			No newline at end of file

services/core/java/com/android/server/vcn/routeselection/IpSecPacketLossDetector.java

+75 −3

Original line number	Original line	Diff line number	Diff line
	@@ -70,6 +70,7 @@ public class IpSecPacketLossDetector extends NetworkMetricMonitor {
	value = {		value = {
	PACKET_LOSS_RATE_VALID,		PACKET_LOSS_RATE_VALID,
	PACKET_LOSS_RATE_INVALID,		PACKET_LOSS_RATE_INVALID,
			PACKET_LOSS_UNUSUAL_SEQ_NUM_LEAP,
	})		})
	@Target({ElementType.TYPE_USE})		@Target({ElementType.TYPE_USE})
	private @interface PacketLossResultType {}		private @interface PacketLossResultType {}
	@@ -89,6 +90,16 @@ public class IpSecPacketLossDetector extends NetworkMetricMonitor {
	*/		*/
	private static final int PACKET_LOSS_RATE_INVALID = 1;		private static final int PACKET_LOSS_RATE_INVALID = 1;

			/**
			* The sequence number increase is unusually large and might be caused an intentional leap on
			* the server's downlink
			*
			* <p>Inbound sequence number will not always increase consecutively. During load balancing the
			* server might add a big leap on the sequence number intentionally. In such case a high packet
			* loss rate does not always indicate a lossy network
			*/
			private static final int PACKET_LOSS_UNUSUAL_SEQ_NUM_LEAP = 2;

	// For VoIP, losses between 5% and 10% of the total packet stream will affect the quality		// For VoIP, losses between 5% and 10% of the total packet stream will affect the quality
	// significantly (as per "Computer Networking for LANS to WANS: Hardware, Software and		// significantly (as per "Computer Networking for LANS to WANS: Hardware, Software and
	// Security"). For audio and video streaming, above 10-12% packet loss is unacceptable (as per		// Security"). For audio and video streaming, above 10-12% packet loss is unacceptable (as per
	@@ -98,8 +109,12 @@ public class IpSecPacketLossDetector extends NetworkMetricMonitor {

	private static final int POLL_IPSEC_STATE_INTERVAL_SECONDS_DEFAULT = 20;		private static final int POLL_IPSEC_STATE_INTERVAL_SECONDS_DEFAULT = 20;

			// By default, there's no maximum limit enforced
			private static final int MAX_SEQ_NUM_INCREASE_DEFAULT_DISABLED = -1;

	private long mPollIpSecStateIntervalMs;		private long mPollIpSecStateIntervalMs;
	private final int mPacketLossRatePercentThreshold;		private final int mPacketLossRatePercentThreshold;
			private int mMaxSeqNumIncreasePerSecond;

	@NonNull private final Handler mHandler;		@NonNull private final Handler mHandler;
	@NonNull private final PowerManager mPowerManager;		@NonNull private final PowerManager mPowerManager;
	@@ -138,6 +153,7 @@ public class IpSecPacketLossDetector extends NetworkMetricMonitor {

	mPollIpSecStateIntervalMs = getPollIpSecStateIntervalMs(carrierConfig);		mPollIpSecStateIntervalMs = getPollIpSecStateIntervalMs(carrierConfig);
	mPacketLossRatePercentThreshold = getPacketLossRatePercentThreshold(carrierConfig);		mPacketLossRatePercentThreshold = getPacketLossRatePercentThreshold(carrierConfig);
			mMaxSeqNumIncreasePerSecond = getMaxSeqNumIncreasePerSecond(carrierConfig);

	// Register for system broadcasts to monitor idle mode change		// Register for system broadcasts to monitor idle mode change
	final IntentFilter intentFilter = new IntentFilter();		final IntentFilter intentFilter = new IntentFilter();
	@@ -202,6 +218,24 @@ public class IpSecPacketLossDetector extends NetworkMetricMonitor {
	return IPSEC_PACKET_LOSS_PERCENT_THRESHOLD_DEFAULT;		return IPSEC_PACKET_LOSS_PERCENT_THRESHOLD_DEFAULT;
	}		}

			@VisibleForTesting(visibility = Visibility.PRIVATE)
			static int getMaxSeqNumIncreasePerSecond(@Nullable PersistableBundleWrapper carrierConfig) {
			int maxSeqNumIncrease = MAX_SEQ_NUM_INCREASE_DEFAULT_DISABLED;
			if (Flags.handleSeqNumLeap() && carrierConfig != null) {
			maxSeqNumIncrease =
			carrierConfig.getInt(
			VcnManager.VCN_NETWORK_SELECTION_MAX_SEQ_NUM_INCREASE_PER_SECOND_KEY,
			MAX_SEQ_NUM_INCREASE_DEFAULT_DISABLED);
			}

			if (maxSeqNumIncrease < MAX_SEQ_NUM_INCREASE_DEFAULT_DISABLED) {
			logE(TAG, "Invalid value of MAX_SEQ_NUM_INCREASE_PER_SECOND_KEY " + maxSeqNumIncrease);
			return MAX_SEQ_NUM_INCREASE_DEFAULT_DISABLED;
			}

			return maxSeqNumIncrease;
			}

	@Override		@Override
	protected void onSelectedUnderlyingNetworkChanged() {		protected void onSelectedUnderlyingNetworkChanged() {
	if (!isSelectedUnderlyingNetwork()) {		if (!isSelectedUnderlyingNetwork()) {
	@@ -237,6 +271,10 @@ public class IpSecPacketLossDetector extends NetworkMetricMonitor {
	// The already scheduled event will not be affected. The followup events will be scheduled		// The already scheduled event will not be affected. The followup events will be scheduled
	// with the new interval		// with the new interval
	mPollIpSecStateIntervalMs = getPollIpSecStateIntervalMs(carrierConfig);		mPollIpSecStateIntervalMs = getPollIpSecStateIntervalMs(carrierConfig);

			if (Flags.handleSeqNumLeap()) {
			mMaxSeqNumIncreasePerSecond = getMaxSeqNumIncreasePerSecond(carrierConfig);
			}
	}		}

	@Override		@Override
	@@ -339,7 +377,10 @@ public class IpSecPacketLossDetector extends NetworkMetricMonitor {

	final PacketLossCalculationResult calculateResult =		final PacketLossCalculationResult calculateResult =
	mPacketLossCalculator.getPacketLossRatePercentage(		mPacketLossCalculator.getPacketLossRatePercentage(
	mLastIpSecTransformState, state, getLogPrefix());		mLastIpSecTransformState,
			state,
			mMaxSeqNumIncreasePerSecond,
			getLogPrefix());

	if (calculateResult.getResultType() == PACKET_LOSS_RATE_INVALID) {		if (calculateResult.getResultType() == PACKET_LOSS_RATE_INVALID) {
	return;		return;
	@@ -356,11 +397,18 @@ public class IpSecPacketLossDetector extends NetworkMetricMonitor {
	mLastIpSecTransformState = state;		mLastIpSecTransformState = state;
	if (calculateResult.getPacketLossRatePercent() < mPacketLossRatePercentThreshold) {		if (calculateResult.getPacketLossRatePercent() < mPacketLossRatePercentThreshold) {
	logV(logMsg);		logV(logMsg);

			// In both "valid" or "unusual_seq_num_leap" cases, notify that the network has passed
			// the validation
	onValidationResultReceivedInternal(false /* isFailed */);		onValidationResultReceivedInternal(false /* isFailed */);
	} else {		} else {
	logInfo(logMsg);		logInfo(logMsg);

			if (calculateResult.getResultType() == PACKET_LOSS_RATE_VALID) {
	onValidationResultReceivedInternal(true /* isFailed */);		onValidationResultReceivedInternal(true /* isFailed */);
			}

			// In both "valid" or "unusual_seq_num_leap" cases, trigger network validation
	if (Flags.validateNetworkOnIpsecLoss()) {		if (Flags.validateNetworkOnIpsecLoss()) {
	// Trigger re-validation of the underlying network; if it fails, the VCN will		// Trigger re-validation of the underlying network; if it fails, the VCN will
	// attempt to migrate away.		// attempt to migrate away.
	@@ -376,6 +424,7 @@ public class IpSecPacketLossDetector extends NetworkMetricMonitor {
	public PacketLossCalculationResult getPacketLossRatePercentage(		public PacketLossCalculationResult getPacketLossRatePercentage(
	@NonNull IpSecTransformState oldState,		@NonNull IpSecTransformState oldState,
	@NonNull IpSecTransformState newState,		@NonNull IpSecTransformState newState,
			int maxSeqNumIncreasePerSecond,
	String logPrefix) {		String logPrefix) {
	logVIpSecTransform("oldState", oldState, logPrefix);		logVIpSecTransform("oldState", oldState, logPrefix);
	logVIpSecTransform("newState", newState, logPrefix);		logVIpSecTransform("newState", newState, logPrefix);
	@@ -392,6 +441,22 @@ public class IpSecPacketLossDetector extends NetworkMetricMonitor {
	return PacketLossCalculationResult.invalid();		return PacketLossCalculationResult.invalid();
	}		}

			boolean isUnusualSeqNumLeap = false;

			// Handle sequence number leap
			if (Flags.handleSeqNumLeap()
			&& maxSeqNumIncreasePerSecond != MAX_SEQ_NUM_INCREASE_DEFAULT_DISABLED) {
			final long timeDiffMillis =
			newState.getTimestampMillis() - oldState.getTimestampMillis();
			final long maxSeqNumIncrease = timeDiffMillis * maxSeqNumIncreasePerSecond / 1000;

			// Sequence numbers are unsigned 32-bit values. If maxSeqNumIncrease overflows,
			// isUnusualSeqNumLeap can never be true.
			if (maxSeqNumIncrease >= 0 && newSeqHi - oldSeqHi >= maxSeqNumIncrease) {
			isUnusualSeqNumLeap = true;
			}
			}

	// Get the expected packet count by assuming there is no packet loss. In this case, SA		// Get the expected packet count by assuming there is no packet loss. In this case, SA
	// should receive all packets whose sequence numbers are smaller than the lower bound of		// should receive all packets whose sequence numbers are smaller than the lower bound of
	// the replay window AND the packets received within the window.		// the replay window AND the packets received within the window.
	@@ -420,7 +485,9 @@ public class IpSecPacketLossDetector extends NetworkMetricMonitor {
	}		}

	final int percent = 100 - (int) (actualPktCntDiff * 100 / expectedPktCntDiff);		final int percent = 100 - (int) (actualPktCntDiff * 100 / expectedPktCntDiff);
	return PacketLossCalculationResult.valid(percent);		return isUnusualSeqNumLeap
			? PacketLossCalculationResult.unusualSeqNumLeap(percent)
			: PacketLossCalculationResult.valid(percent);
	}		}
	}		}

	@@ -462,6 +529,11 @@ public class IpSecPacketLossDetector extends NetworkMetricMonitor {
	PACKET_LOSS_RATE_INVALID, PACKET_LOSS_PERCENT_UNAVAILABLE);		PACKET_LOSS_RATE_INVALID, PACKET_LOSS_PERCENT_UNAVAILABLE);
	}		}

			/** Construct an instance indicating that there is an unusual sequence number leap */
			public static PacketLossCalculationResult unusualSeqNumLeap(int percent) {
			return new PacketLossCalculationResult(PACKET_LOSS_UNUSUAL_SEQ_NUM_LEAP, percent);
			}

	@PacketLossResultType		@PacketLossResultType
	public int getResultType() {		public int getResultType() {
	return mResultType;		return mResultType;

services/core/java/com/android/server/vcn/routeselection/NetworkMetricMonitor.java

+5 −0

Original line number	Original line	Diff line number	Diff line
	@@ -272,6 +272,11 @@ public abstract class NetworkMetricMonitor implements AutoCloseable {
	}		}
	}		}

			protected static void logE(String className, String msgWithPrefix) {
			Slog.w(className, msgWithPrefix);
			LOCAL_LOG.log("[ERROR ] " + className + msgWithPrefix);
			}

	protected static void logWtf(String className, String msgWithPrefix) {		protected static void logWtf(String className, String msgWithPrefix) {
	Slog.wtf(className, msgWithPrefix);		Slog.wtf(className, msgWithPrefix);
	LOCAL_LOG.log("[WTF ] " + className + msgWithPrefix);		LOCAL_LOG.log("[WTF ] " + className + msgWithPrefix);

tests/vcn/java/com/android/server/vcn/routeselection/IpSecPacketLossDetectorTest.java

+105 −6

Original line number	Original line	Diff line number	Diff line
	@@ -17,8 +17,10 @@
	package com.android.server.vcn.routeselection;		package com.android.server.vcn.routeselection;

	import static android.net.vcn.VcnManager.VCN_NETWORK_SELECTION_IPSEC_PACKET_LOSS_PERCENT_THRESHOLD_KEY;		import static android.net.vcn.VcnManager.VCN_NETWORK_SELECTION_IPSEC_PACKET_LOSS_PERCENT_THRESHOLD_KEY;
			import static android.net.vcn.VcnManager.VCN_NETWORK_SELECTION_MAX_SEQ_NUM_INCREASE_PER_SECOND_KEY;
	import static android.net.vcn.VcnManager.VCN_NETWORK_SELECTION_POLL_IPSEC_STATE_INTERVAL_SECONDS_KEY;		import static android.net.vcn.VcnManager.VCN_NETWORK_SELECTION_POLL_IPSEC_STATE_INTERVAL_SECONDS_KEY;

			import static com.android.server.vcn.routeselection.IpSecPacketLossDetector.getMaxSeqNumIncreasePerSecond;
	import static com.android.server.vcn.util.PersistableBundleUtils.PersistableBundleWrapper;		import static com.android.server.vcn.util.PersistableBundleUtils.PersistableBundleWrapper;

	import static org.junit.Assert.assertEquals;		import static org.junit.Assert.assertEquals;
	@@ -65,6 +67,7 @@ public class IpSecPacketLossDetectorTest extends NetworkEvaluationTestBase {
	private static final int REPLAY_BITMAP_LEN_BYTE = 512;		private static final int REPLAY_BITMAP_LEN_BYTE = 512;
	private static final int REPLAY_BITMAP_LEN_BIT = REPLAY_BITMAP_LEN_BYTE * 8;		private static final int REPLAY_BITMAP_LEN_BIT = REPLAY_BITMAP_LEN_BYTE * 8;
	private static final int IPSEC_PACKET_LOSS_PERCENT_THRESHOLD = 5;		private static final int IPSEC_PACKET_LOSS_PERCENT_THRESHOLD = 5;
			private static final int MAX_SEQ_NUM_INCREASE_DEFAULT_DISABLED = -1;
	private static final long POLL_IPSEC_STATE_INTERVAL_MS = TimeUnit.SECONDS.toMillis(30L);		private static final long POLL_IPSEC_STATE_INTERVAL_MS = TimeUnit.SECONDS.toMillis(30L);

	@Mock private IpSecTransformWrapper mIpSecTransform;		@Mock private IpSecTransformWrapper mIpSecTransform;
	@@ -91,6 +94,9 @@ public class IpSecPacketLossDetectorTest extends NetworkEvaluationTestBase {
	eq(VCN_NETWORK_SELECTION_IPSEC_PACKET_LOSS_PERCENT_THRESHOLD_KEY),		eq(VCN_NETWORK_SELECTION_IPSEC_PACKET_LOSS_PERCENT_THRESHOLD_KEY),
	anyInt()))		anyInt()))
	.thenReturn(IPSEC_PACKET_LOSS_PERCENT_THRESHOLD);		.thenReturn(IPSEC_PACKET_LOSS_PERCENT_THRESHOLD);
			when(mCarrierConfig.getInt(
			eq(VCN_NETWORK_SELECTION_MAX_SEQ_NUM_INCREASE_PER_SECOND_KEY), anyInt()))
			.thenReturn(MAX_SEQ_NUM_INCREASE_DEFAULT_DISABLED);

	when(mDependencies.getPacketLossCalculator()).thenReturn(mPacketLossCalculator);		when(mDependencies.getPacketLossCalculator()).thenReturn(mPacketLossCalculator);

	@@ -112,6 +118,20 @@ public class IpSecPacketLossDetectorTest extends NetworkEvaluationTestBase {
	.build();		.build();
	}		}

			private static IpSecTransformState newNextTransformState(
			IpSecTransformState before,
			long timeDiffMillis,
			long rxSeqNoDiff,
			long packtCountDiff,
			int packetInWin) {
			return new IpSecTransformState.Builder()
			.setTimestampMillis(before.getTimestampMillis() + timeDiffMillis)
			.setRxHighestSequenceNumber(before.getRxHighestSequenceNumber() + rxSeqNoDiff)
			.setPacketCount(before.getPacketCount() + packtCountDiff)
			.setReplayBitmap(newReplayBitmap(packetInWin))
			.build();
			}

	private static byte[] newReplayBitmap(int receivedPktCnt) {		private static byte[] newReplayBitmap(int receivedPktCnt) {
	final BitSet bitSet = new BitSet(REPLAY_BITMAP_LEN_BIT);		final BitSet bitSet = new BitSet(REPLAY_BITMAP_LEN_BIT);
	for (int i = 0; i < receivedPktCnt; i++) {		for (int i = 0; i < receivedPktCnt; i++) {
	@@ -165,7 +185,7 @@ public class IpSecPacketLossDetectorTest extends NetworkEvaluationTestBase {
	// Verify the first polled state is stored		// Verify the first polled state is stored
	assertEquals(mTransformStateInitial, mIpSecPacketLossDetector.getLastTransformState());		assertEquals(mTransformStateInitial, mIpSecPacketLossDetector.getLastTransformState());
	verify(mPacketLossCalculator, never())		verify(mPacketLossCalculator, never())
	.getPacketLossRatePercentage(any(), any(), anyString());		.getPacketLossRatePercentage(any(), any(), anyInt(), anyString());

	// Verify next poll is scheduled		// Verify next poll is scheduled
	assertNull(mTestLooper.nextMessage());		assertNull(mTestLooper.nextMessage());
	@@ -278,7 +298,7 @@ public class IpSecPacketLossDetectorTest extends NetworkEvaluationTestBase {

	xfrmStateReceiver.onResult(newTransformState(1, 1, newReplayBitmap(1)));		xfrmStateReceiver.onResult(newTransformState(1, 1, newReplayBitmap(1)));
	verify(mPacketLossCalculator, never())		verify(mPacketLossCalculator, never())
	.getPacketLossRatePercentage(any(), any(), anyString());		.getPacketLossRatePercentage(any(), any(), anyInt(), anyString());
	}		}

	@Test		@Test
	@@ -289,7 +309,7 @@ public class IpSecPacketLossDetectorTest extends NetworkEvaluationTestBase {

	xfrmStateReceiver.onError(new RuntimeException("Test"));		xfrmStateReceiver.onError(new RuntimeException("Test"));
	verify(mPacketLossCalculator, never())		verify(mPacketLossCalculator, never())
	.getPacketLossRatePercentage(any(), any(), anyString());		.getPacketLossRatePercentage(any(), any(), anyInt(), anyString());
	}		}

	private void checkHandleLossRate(		private void checkHandleLossRate(
	@@ -301,7 +321,7 @@ public class IpSecPacketLossDetectorTest extends NetworkEvaluationTestBase {
	startMonitorAndCaptureStateReceiver();		startMonitorAndCaptureStateReceiver();
	doReturn(mockPacketLossRate)		doReturn(mockPacketLossRate)
	.when(mPacketLossCalculator)		.when(mPacketLossCalculator)
	.getPacketLossRatePercentage(any(), any(), anyString());		.getPacketLossRatePercentage(any(), any(), anyInt(), anyString());

	// Mock receiving two states with mTransformStateInitial and an arbitrary transformNew		// Mock receiving two states with mTransformStateInitial and an arbitrary transformNew
	final IpSecTransformState transformNew = newTransformState(1, 1, newReplayBitmap(1));		final IpSecTransformState transformNew = newTransformState(1, 1, newReplayBitmap(1));
	@@ -311,7 +331,10 @@ public class IpSecPacketLossDetectorTest extends NetworkEvaluationTestBase {
	// Verifications		// Verifications
	verify(mPacketLossCalculator)		verify(mPacketLossCalculator)
	.getPacketLossRatePercentage(		.getPacketLossRatePercentage(
	eq(mTransformStateInitial), eq(transformNew), anyString());		eq(mTransformStateInitial),
			eq(transformNew),
			eq(MAX_SEQ_NUM_INCREASE_DEFAULT_DISABLED),
			anyString());

	if (isLastStateExpectedToUpdate) {		if (isLastStateExpectedToUpdate) {
	assertEquals(transformNew, mIpSecPacketLossDetector.getLastTransformState());		assertEquals(transformNew, mIpSecPacketLossDetector.getLastTransformState());
	@@ -351,6 +374,22 @@ public class IpSecPacketLossDetectorTest extends NetworkEvaluationTestBase {
	false /* isCallbackExpected */);		false /* isCallbackExpected */);
	}		}

			@Test
			public void testHandleLossRate_unusualSeqNumLeap_highLossRate() throws Exception {
			checkHandleLossRate(
			PacketLossCalculationResult.unusualSeqNumLeap(22),
			true /* isLastStateExpectedToUpdate */,
			false /* isCallbackExpected */);
			}

			@Test
			public void testHandleLossRate_unusualSeqNumLeap_lowLossRate() throws Exception {
			checkHandleLossRate(
			PacketLossCalculationResult.unusualSeqNumLeap(2),
			true /* isLastStateExpectedToUpdate */,
			true /* isCallbackExpected */);
			}

	private void checkGetPacketLossRate(		private void checkGetPacketLossRate(
	IpSecTransformState oldState,		IpSecTransformState oldState,
	IpSecTransformState newState,		IpSecTransformState newState,
	@@ -358,7 +397,8 @@ public class IpSecPacketLossDetectorTest extends NetworkEvaluationTestBase {
	throws Exception {		throws Exception {
	assertEquals(		assertEquals(
	expectedLossRate,		expectedLossRate,
	mPacketLossCalculator.getPacketLossRatePercentage(oldState, newState, TAG));		mPacketLossCalculator.getPacketLossRatePercentage(
			oldState, newState, MAX_SEQ_NUM_INCREASE_DEFAULT_DISABLED, TAG));
	}		}

	private void checkGetPacketLossRate(		private void checkGetPacketLossRate(
	@@ -443,6 +483,45 @@ public class IpSecPacketLossDetectorTest extends NetworkEvaluationTestBase {
	checkGetPacketLossRate(oldState, 20000, 14000, 3000, 10);		checkGetPacketLossRate(oldState, 20000, 14000, 3000, 10);
	}		}

			private void checkGetPktLossRate_unusualSeqNumLeap(
			int maxSeqNumIncreasePerSecond,
			int timeDiffMillis,
			int rxSeqNoDiff,
			PacketLossCalculationResult expected)
			throws Exception {
			final IpSecTransformState oldState = mTransformStateInitial;
			final IpSecTransformState newState =
			newNextTransformState(
			oldState,
			timeDiffMillis,
			rxSeqNoDiff,
			1 /* packtCountDiff */,
			1 /* packetInWin */);

			assertEquals(
			expected,
			mPacketLossCalculator.getPacketLossRatePercentage(
			oldState, newState, maxSeqNumIncreasePerSecond, TAG));
			}

			@Test
			public void testGetPktLossRate_unusualSeqNumLeap() throws Exception {
			checkGetPktLossRate_unusualSeqNumLeap(
			10000 /* maxSeqNumIncreasePerSecond */,
			(int) TimeUnit.SECONDS.toMillis(2L),
			30000 /* rxSeqNoDiff */,
			PacketLossCalculationResult.unusualSeqNumLeap(100));
			}

			@Test
			public void testGetPktLossRate_unusualSeqNumLeap_smallSeqNumDiff() throws Exception {
			checkGetPktLossRate_unusualSeqNumLeap(
			10000 /* maxSeqNumIncreasePerSecond */,
			(int) TimeUnit.SECONDS.toMillis(2L),
			5000 /* rxSeqNoDiff */,
			PacketLossCalculationResult.valid(100));
			}

	// Verify the polling event is scheduled with expected delays		// Verify the polling event is scheduled with expected delays
	private void verifyPollEventDelayAndScheduleNext(long expectedDelayMs) {		private void verifyPollEventDelayAndScheduleNext(long expectedDelayMs) {
	if (expectedDelayMs > 0) {		if (expectedDelayMs > 0) {
	@@ -469,4 +548,24 @@ public class IpSecPacketLossDetectorTest extends NetworkEvaluationTestBase {
	// Verify the 3rd poll is scheduled with configured delay		// Verify the 3rd poll is scheduled with configured delay
	verifyPollEventDelayAndScheduleNext(POLL_IPSEC_STATE_INTERVAL_MS);		verifyPollEventDelayAndScheduleNext(POLL_IPSEC_STATE_INTERVAL_MS);
	}		}

			@Test
			public void testGetMaxSeqNumIncreasePerSecond() throws Exception {
			final int seqNumLeapNegative = 500_000;
			when(mCarrierConfig.getInt(
			eq(VCN_NETWORK_SELECTION_MAX_SEQ_NUM_INCREASE_PER_SECOND_KEY), anyInt()))
			.thenReturn(seqNumLeapNegative);
			assertEquals(seqNumLeapNegative, getMaxSeqNumIncreasePerSecond(mCarrierConfig));
			}

			@Test
			public void testGetMaxSeqNumIncreasePerSecond_negativeValue() throws Exception {
			final int seqNumLeapNegative = -10;
			when(mCarrierConfig.getInt(
			eq(VCN_NETWORK_SELECTION_MAX_SEQ_NUM_INCREASE_PER_SECOND_KEY), anyInt()))
			.thenReturn(seqNumLeapNegative);
			assertEquals(
			MAX_SEQ_NUM_INCREASE_DEFAULT_DISABLED,
			getMaxSeqNumIncreasePerSecond(mCarrierConfig));
			}
	}		}