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Commit 1ef8fd87 authored by Xiao Ma's avatar Xiao Ma
Browse files

Restore the default interface MTU when disconnecting from Wi-Fi AP. 

Bug: 113350007
Test: atest FrameworksNetTests NetworkStackTests
Test: atest NetworkStackIntegrationTests
Test: manual test

Change-Id: I709a504885033a330b946de402a261d341f78117
parent c80a667b

src/android/net/ip/IpClient.java

+31 −3
Original line number Diff line number Diff line
@@ -48,6 +48,7 @@ import android.os.ConditionVariable; 
import android.os.IBinder;

import android.os.Message;

import android.os.RemoteException;

import android.os.ServiceSpecificException;

import android.os.SystemClock;

import android.text.TextUtils;

import android.util.LocalLog;
@@ -850,10 +851,12 @@ public class IpClient extends StateMachine { 
        return shouldLog;

    }



    private void logError(String fmt, Throwable e, Object... args) {

        mLog.e(String.format(fmt, args), e);

    }



    private void logError(String fmt, Object... args) {

        final String msg = "ERROR " + String.format(fmt, args);

        Log.e(mTag, msg);

        mLog.log(msg);

        logError(fmt, null, args);

    }



    // This needs to be called with care to ensure that our LinkProperties
@@ -1274,6 +1277,28 @@ public class IpClient extends StateMachine { 
        // TODO : implement this

    }



    private void maybeRestoreInterfaceMtu() {

        InterfaceParams params = mDependencies.getInterfaceParams(mInterfaceName);

        if (params == null) {

            Log.w(mTag, "interface: " + mInterfaceName + " is gone");

            return;

        }



        if (params.index != mInterfaceParams.index) {

            Log.w(mTag, "interface: " + mInterfaceName + " has a different index: " + params.index);

            return;

        }



        if (params.defaultMtu != mInterfaceParams.defaultMtu) {

            try {

                mNetd.interfaceSetMtu(mInterfaceName, mInterfaceParams.defaultMtu);

            } catch (RemoteException | ServiceSpecificException e) {

                logError("Couldn't reset MTU on " + mInterfaceName + " from "

                        + params.defaultMtu + " to " + mInterfaceParams.defaultMtu, e);

            }

        }

    }



    class StoppedState extends State {

        @Override

        public void enter() {
@@ -1351,6 +1376,9 @@ public class IpClient extends StateMachine { 
                // There's no DHCPv4 for which to wait; proceed to stopped.

                deferMessage(obtainMessage(CMD_JUMP_STOPPING_TO_STOPPED));

            }



            // Restore the interface MTU to initial value if it has changed.

            maybeRestoreInterfaceMtu();

        }



        @Override

src/com/android/server/util/NetworkStackConstants.java

+2 −0
Original line number Diff line number Diff line
@@ -54,6 +54,7 @@ public final class NetworkStackConstants { 
    public static final int ETHER_TYPE_IPV4 = 0x0800;

    public static final int ETHER_TYPE_IPV6 = 0x86dd;

    public static final int ETHER_HEADER_LEN = 14;

    public static final int ETHER_MTU = 1500;



    /**

     * ARP constants.
@@ -97,6 +98,7 @@ public final class NetworkStackConstants { 
    public static final int IPV6_PROTOCOL_OFFSET = 6;

    public static final int IPV6_SRC_ADDR_OFFSET = 8;

    public static final int IPV6_DST_ADDR_OFFSET = 24;

    public static final int IPV6_MIN_MTU = 1280;



    /**

     * ICMPv6 constants.

tests/integration/Android.bp

+1 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ android_test { 
        "androidx.annotation_annotation",

        "androidx.test.rules",

        "mockito-target-extended-minus-junit4",

        "net-tests-utils",

        "NetworkStackBase",

        "testables",

    ],

tests/integration/src/android/net/ip/IpClientIntegrationTest.java

+82 −31
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ import static org.junit.Assert.assertNotNull; 
import static org.junit.Assert.assertTrue;

import static org.mockito.Mockito.any;

import static org.mockito.Mockito.doAnswer;

import static org.mockito.Mockito.doThrow;

import static org.mockito.Mockito.eq;

import static org.mockito.Mockito.never;

import static org.mockito.Mockito.timeout;
@@ -77,6 +78,7 @@ import androidx.test.runner.AndroidJUnit4; 
import com.android.server.NetworkObserverRegistry;

import com.android.server.NetworkStackService.NetworkStackServiceManager;

import com.android.server.connectivity.ipmemorystore.IpMemoryStoreService;

import com.android.testutils.HandlerUtilsKt;



import org.junit.After;

import org.junit.Before;
@@ -91,6 +93,7 @@ import java.io.FileDescriptor; 
import java.io.FileOutputStream;

import java.io.IOException;

import java.net.Inet4Address;

import java.net.NetworkInterface;

import java.nio.ByteBuffer;

import java.util.Arrays;

import java.util.Collections;
@@ -112,7 +115,7 @@ public class IpClientIntegrationTest { 


    @Mock private Context mContext;

    @Mock private ConnectivityManager mCm;

    @Mock private INetd mNetd;

    @Mock private INetd mMockNetd;

    @Mock private Resources mResources;

    @Mock private IIpClientCallbacks mCb;

    @Mock private AlarmManager mAlarm;
@@ -122,6 +125,7 @@ public class IpClientIntegrationTest { 
    @Mock private IpMemoryStoreService mIpMemoryStoreService;



    private String mIfaceName;

    private INetd mNetd;

    private HandlerThread mPacketReaderThread;

    private TapPacketReader mPacketReader;

    private IpClient mIpc;
@@ -158,7 +162,8 @@ public class IpClientIntegrationTest { 
    private static final Inet4Address BROADCAST_ADDR = getBroadcastAddress(

            SERVER_ADDR, PREFIX_LENGTH);

    private static final String HOSTNAME = "testhostname";

    private static final short MTU = 1500;

    private static final int TEST_DEFAULT_MTU = 1500;

    private static final int TEST_MIN_MTU = 1280;



    private static class TapPacketReader extends PacketReader {

        private final ParcelFileDescriptor mTapFd;
@@ -214,7 +219,7 @@ public class IpClientIntegrationTest { 


        @Override

        public INetd getNetd(Context context) {

            return mNetd;

            return mMockNetd;

        }



        @Override
@@ -287,7 +292,6 @@ public class IpClientIntegrationTest { 
            inst.getUiAutomation().dropShellPermissionIdentity();

        }

        mIfaceName = iface.getInterfaceName();



        mPacketReaderThread = new HandlerThread(IpClientIntegrationTest.class.getSimpleName());

        mPacketReaderThread.start();
@@ -300,12 +304,12 @@ public class IpClientIntegrationTest { 
        final Instrumentation inst = InstrumentationRegistry.getInstrumentation();

        final IBinder netdIBinder =

                (IBinder) inst.getContext().getSystemService(Context.NETD_SERVICE);

        final INetd netd = INetd.Stub.asInterface(netdIBinder);

        mNetd = INetd.Stub.asInterface(netdIBinder);

        when(mContext.getSystemService(eq(Context.NETD_SERVICE))).thenReturn(netdIBinder);

        assertNotNull(netd);

        assertNotNull(mNetd);



        final NetworkObserverRegistry reg = new NetworkObserverRegistry();

        reg.register(netd);

        reg.register(mNetd);

        mIpc = new IpClient(mContext, mIfaceName, mCb, reg, mNetworkStackServiceManager,

                mDependencies);

    }
@@ -345,7 +349,7 @@ public class IpClientIntegrationTest { 
    }



    private static ByteBuffer buildDhcpOfferPacket(final DhcpPacket packet,

            final Integer leaseTimeSec) {

            final Integer leaseTimeSec, final short mtu) {

        return DhcpPacket.buildOfferPacket(DhcpPacket.ENCAP_L2, packet.getTransactionId(),

                false /* broadcast */, SERVER_ADDR, INADDR_ANY /* relayIp */,

                CLIENT_ADDR /* yourIp */, packet.getClientMac(), leaseTimeSec,
@@ -353,11 +357,11 @@ public class IpClientIntegrationTest { 
                Collections.singletonList(SERVER_ADDR) /* gateways */,

                Collections.singletonList(SERVER_ADDR) /* dnsServers */,

                SERVER_ADDR /* dhcpServerIdentifier */, null /* domainName */, HOSTNAME,

                false /* metered */, MTU);

                false /* metered */, mtu);

    }



    private static ByteBuffer buildDhcpAckPacket(final DhcpPacket packet,

            final Integer leaseTimeSec) {

            final Integer leaseTimeSec, final short mtu) {

        return DhcpPacket.buildAckPacket(DhcpPacket.ENCAP_L2, packet.getTransactionId(),

                false /* broadcast */, SERVER_ADDR, INADDR_ANY /* relayIp */,

                CLIENT_ADDR /* yourIp */, CLIENT_ADDR /* requestIp */, packet.getClientMac(),
@@ -365,7 +369,7 @@ public class IpClientIntegrationTest { 
                Collections.singletonList(SERVER_ADDR) /* gateways */,

                Collections.singletonList(SERVER_ADDR) /* dnsServers */,

                SERVER_ADDR /* dhcpServerIdentifier */, null /* domainName */, HOSTNAME,

                false /* metered */, MTU);

                false /* metered */, mtu);

    }



    private static ByteBuffer buildDhcpNakPacket(final DhcpPacket packet) {
@@ -397,7 +401,7 @@ public class IpClientIntegrationTest { 
    }



    private void assertIpMemoryStoreNetworkAttributes(final Integer leaseTimeSec,

            final long startTime) {

            final long startTime, final int mtu) {

        final ArgumentCaptor<NetworkAttributes> networkAttributes =

                ArgumentCaptor.forClass(NetworkAttributes.class);
@@ -416,7 +420,7 @@ public class IpClientIntegrationTest { 
            assertTrue(lowerBound < expiry);

        }

        assertEquals(Collections.singletonList(SERVER_ADDR), naValueCaptured.dnsAddresses);

        assertEquals(new Integer((int) MTU), naValueCaptured.mtu);

        assertEquals(new Integer(mtu), naValueCaptured.mtu);

    }



    private void assertIpMemoryNeverStoreNetworkAttributes() {
@@ -426,20 +430,20 @@ public class IpClientIntegrationTest { 
    // Helper method to complete DHCP 2-way or 4-way handshake

    private void performDhcpHandshake(final boolean isSuccessLease,

            final Integer leaseTimeSec, final boolean isDhcpLeaseCacheEnabled,

            final boolean isDhcpRapidCommitEnabled) throws Exception {

            final boolean isDhcpRapidCommitEnabled, final int mtu) throws Exception {

        startIpClientProvisioning(isDhcpLeaseCacheEnabled, isDhcpRapidCommitEnabled);



        DhcpPacket packet;

        while ((packet = getNextDhcpPacket()) != null) {

            if (packet instanceof DhcpDiscoverPacket) {

                if (isDhcpRapidCommitEnabled) {

                    sendResponse(buildDhcpAckPacket(packet, leaseTimeSec));

                    sendResponse(buildDhcpAckPacket(packet, leaseTimeSec, (short) mtu));

                } else {

                    sendResponse(buildDhcpOfferPacket(packet, leaseTimeSec));

                    sendResponse(buildDhcpOfferPacket(packet, leaseTimeSec, (short) mtu));

                }

            } else if (packet instanceof DhcpRequestPacket) {

                final ByteBuffer byteBuffer = isSuccessLease

                        ? buildDhcpAckPacket(packet, leaseTimeSec)

                        ? buildDhcpAckPacket(packet, leaseTimeSec, (short) mtu)

                        : buildDhcpNakPacket(packet);

                sendResponse(byteBuffer);

            } else {
@@ -474,6 +478,28 @@ public class IpClientIntegrationTest { 
        return getNextDhcpPacket();

    }



    private void doRestoreInitialMtuTest(final boolean shouldChangeMtu) throws Exception {

        final long currentTime = System.currentTimeMillis();

        int mtu = TEST_DEFAULT_MTU;



        if (shouldChangeMtu) mtu = TEST_MIN_MTU;

        performDhcpHandshake(true /* isSuccessLease */, TEST_LEASE_DURATION_S,

                true /* isDhcpLeaseCacheEnabled */, false /* isDhcpRapidCommitEnabled */, mtu);

        assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, mtu);



        if (shouldChangeMtu) {

            // Pretend that ConnectivityService set the MTU.

            mNetd.interfaceSetMtu(mIfaceName, mtu);

            assertEquals(NetworkInterface.getByName(mIfaceName).getMTU(), mtu);

        }



        mIpc.shutdown();

        HandlerUtilsKt.waitForIdle(mIpc.getHandler(), TEST_TIMEOUT_MS);

        // Verify that MTU indeed has been restored or not.

        verify(mMockNetd, times(shouldChangeMtu ? 1 : 0)).interfaceSetMtu(mIfaceName,

                TEST_DEFAULT_MTU);

    }



    @Test

    public void testDhcpInit() throws Exception {

        startIpClientProvisioning(false /* isDhcpLeaseCacheEnabled */,
@@ -486,14 +512,16 @@ public class IpClientIntegrationTest { 
    public void testHandleSuccessDhcpLease() throws Exception {

        final long currentTime = System.currentTimeMillis();

        performDhcpHandshake(true /* isSuccessLease */, TEST_LEASE_DURATION_S,

                true /* isDhcpLeaseCacheEnabled */, false /* isDhcpRapidCommitEnabled */);

        assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime);

                true /* isDhcpLeaseCacheEnabled */, false /* isDhcpRapidCommitEnabled */,

                TEST_DEFAULT_MTU);

        assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, TEST_DEFAULT_MTU);

    }



    @Test

    public void testHandleFailureDhcpLease() throws Exception {

        performDhcpHandshake(false /* isSuccessLease */, TEST_LEASE_DURATION_S,

                true /* isDhcpLeaseCacheEnabled */, false /* isDhcpRapidCommitEnabled */);

                true /* isDhcpLeaseCacheEnabled */, false /* isDhcpRapidCommitEnabled */,

                TEST_DEFAULT_MTU);

        assertIpMemoryNeverStoreNetworkAttributes();

    }
@@ -501,22 +529,25 @@ public class IpClientIntegrationTest { 
    public void testHandleInfiniteLease() throws Exception {

        final long currentTime = System.currentTimeMillis();

        performDhcpHandshake(true /* isSuccessLease */, INFINITE_LEASE,

                true /* isDhcpLeaseCacheEnabled */, false /* isDhcpRapidCommitEnabled */);

        assertIpMemoryStoreNetworkAttributes(INFINITE_LEASE, currentTime);

                true /* isDhcpLeaseCacheEnabled */, false /* isDhcpRapidCommitEnabled */,

                TEST_DEFAULT_MTU);

        assertIpMemoryStoreNetworkAttributes(INFINITE_LEASE, currentTime, TEST_DEFAULT_MTU);

    }



    @Test

    public void testHandleNoLease() throws Exception {

        final long currentTime = System.currentTimeMillis();

        performDhcpHandshake(true /* isSuccessLease */, null /* no lease time */,

                true /* isDhcpLeaseCacheEnabled */, false /* isDhcpRapidCommitEnabled */);

        assertIpMemoryStoreNetworkAttributes(null, currentTime);

                true /* isDhcpLeaseCacheEnabled */, false /* isDhcpRapidCommitEnabled */,

                TEST_DEFAULT_MTU);

        assertIpMemoryStoreNetworkAttributes(null, currentTime, TEST_DEFAULT_MTU);

    }



    @Test

    public void testHandleDisableInitRebootState() throws Exception {

        performDhcpHandshake(true /* isSuccessLease */, TEST_LEASE_DURATION_S,

                false /* isDhcpLeaseCacheEnabled */, false /* isDhcpRapidCommitEnabled */);

                false /* isDhcpLeaseCacheEnabled */, false /* isDhcpRapidCommitEnabled */,

                TEST_DEFAULT_MTU);

        assertIpMemoryNeverStoreNetworkAttributes();

    }
@@ -526,8 +557,9 @@ public class IpClientIntegrationTest { 
        // TODO: remove @Ignore after supporting rapid commit option in DHCP server

        final long currentTime = System.currentTimeMillis();

        performDhcpHandshake(true /* isSuccessLease */, TEST_LEASE_DURATION_S,

                true /* isDhcpLeaseCacheEnabled */, true /* isDhcpRapidCommitEnabled */);

        assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime);

                true /* isDhcpLeaseCacheEnabled */, true /* isDhcpRapidCommitEnabled */,

                TEST_DEFAULT_MTU);

        assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, TEST_DEFAULT_MTU);

    }



    @Test
@@ -536,7 +568,7 @@ public class IpClientIntegrationTest { 
                new NetworkAttributes.Builder()

                    .setAssignedV4Address(CLIENT_ADDR)

                    .setAssignedV4AddressExpiry(Long.MAX_VALUE) // lease is always valid

                    .setMtu(new Integer(MTU))

                    .setMtu(new Integer(TEST_DEFAULT_MTU))

                    .setGroupHint(TEST_GROUPHINT)

                    .setDnsAddresses(Collections.singletonList(SERVER_ADDR))

                    .build(), false /* timeout */);
@@ -549,7 +581,7 @@ public class IpClientIntegrationTest { 
                 new NetworkAttributes.Builder()

                    .setAssignedV4Address(CLIENT_ADDR)

                    .setAssignedV4AddressExpiry(EXPIRED_LEASE)

                    .setMtu(new Integer(MTU))

                    .setMtu(new Integer(TEST_DEFAULT_MTU))

                    .setGroupHint(TEST_GROUPHINT)

                    .setDnsAddresses(Collections.singletonList(SERVER_ADDR))

                    .build(), false /* timeout */);
@@ -568,7 +600,7 @@ public class IpClientIntegrationTest { 
                new NetworkAttributes.Builder()

                    .setAssignedV4Address(CLIENT_ADDR)

                    .setAssignedV4AddressExpiry(System.currentTimeMillis() + 3_600_000)

                    .setMtu(new Integer(MTU))

                    .setMtu(new Integer(TEST_DEFAULT_MTU))

                    .setGroupHint(TEST_GROUPHINT)

                    .setDnsAddresses(Collections.singletonList(SERVER_ADDR))

                    .build(), true /* timeout */);
@@ -579,7 +611,7 @@ public class IpClientIntegrationTest { 
    public void testDhcpClientStartWithCachedLeaseWithoutIPAddress() throws Exception {

        final DhcpPacket packet = getReplyFromDhcpLease(

                new NetworkAttributes.Builder()

                    .setMtu(new Integer(MTU))

                    .setMtu(new Integer(TEST_DEFAULT_MTU))

                    .setGroupHint(TEST_GROUPHINT)

                    .setDnsAddresses(Collections.singletonList(SERVER_ADDR))

                    .build(), false /* timeout */);
@@ -593,4 +625,23 @@ public class IpClientIntegrationTest { 
        final DhcpPacket packet = getNextDhcpPacket();

        assertTrue(DhcpDiscoverPacket.class.isInstance(packet));

    }



    @Test

    public void testRestoreInitialInterfaceMtu() throws Exception {

        doRestoreInitialMtuTest(true /* shouldChangeMtu */);

    }



    @Test

    public void testRestoreInitialInterfaceMtuWithoutChange() throws Exception {

        doRestoreInitialMtuTest(false /* shouldChangeMtu */);

    }



    @Test

    public void testRestoreInitialInterfaceMtuWithException() throws Exception {

        doThrow(new RemoteException("NetdNativeService::interfaceSetMtu")).when(mMockNetd)

                .interfaceSetMtu(mIfaceName, TEST_DEFAULT_MTU);



        doRestoreInitialMtuTest(true /* shouldChangeMtu */);

        assertEquals(NetworkInterface.getByName(mIfaceName).getMTU(), TEST_MIN_MTU);

    }

}