Restore the default interface MTU when disconnecting from Wi-Fi AP. am:... (b8776d5a) · Commits · e / os / android_packages_modules_NetworkStack

src/android/net/ip/IpClient.java

+36 −3

Original line number	Diff line number	Diff line
		@@ -19,6 +19,7 @@ package android.net.ip;
		import static android.net.RouteInfo.RTN_UNICAST;
		import static android.net.shared.IpConfigurationParcelableUtil.toStableParcelable;

		import static com.android.server.util.NetworkStackConstants.ETHER_MTU;
		import static com.android.server.util.PermissionUtil.checkNetworkStackCallingPermission;

		import android.annotation.NonNull;
		@@ -48,6 +49,7 @@ 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;
		@@ -69,6 +71,8 @@ import com.android.server.NetworkStackService.NetworkStackServiceManager;
		import java.io.FileDescriptor;
		import java.io.PrintWriter;
		import java.net.InetAddress;
		import java.net.NetworkInterface;
		import java.net.SocketException;
		import java.util.Collection;
		import java.util.List;
		import java.util.Objects;
		@@ -380,6 +384,8 @@ public class IpClient extends StateMachine {
		private final ConditionVariable mApfDataSnapshotComplete = new ConditionVariable();

		public static class Dependencies {
		private static final String TAG = "IpClient.Dependencies";

		/**
		* Get interface parameters for the specified interface.
		*/
		@@ -387,6 +393,18 @@ public class IpClient extends StateMachine {
		return InterfaceParams.getByName(ifname);
		}

		/**
		* Get the current MTU for the specified interface.
		*/
		public int getInterfaceMtu(String ifname) {
		try {
		return NetworkInterface.getByName(ifname).getMTU();
		} catch (SocketException e) {
		Log.e(TAG, "unexpected failure to get the interface MTU");
		return ETHER_MTU;
		}
		}

		/**
		* Get a INetd connector.
		*/
		@@ -850,10 +868,14 @@ public class IpClient extends StateMachine {
		return shouldLog;
		}

		private void logError(String fmt, Object... args) {
		private void logError(String fmt, Throwable e, Object... args) {
		final String msg = "ERROR " + String.format(fmt, args);
		Log.e(mTag, msg);
		mLog.log(msg);
		Log.e(mTag, msg, e);
		mLog.e(msg, e);
		}

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

		// This needs to be called with care to ensure that our LinkProperties
		@@ -1351,6 +1373,17 @@ 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.
		final int mtu = mDependencies.getInterfaceMtu(mInterfaceName);
		try {
		if (mtu != mInterfaceParams.defaultMtu) {
		mNetd.interfaceSetMtu(mInterfaceName, mInterfaceParams.defaultMtu);
		}
		} catch (RemoteException \| ServiceSpecificException e) {
		logError("Couldn't reset MTU from "
		+ mtu + " to " + mInterfaceParams.defaultMtu + ": " + e);
		}
		}

		@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

+52 −18

Original line number	Diff line number	Diff line
		@@ -77,6 +77,7 @@ 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;
		@@ -158,7 +159,8 @@ 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;
		@@ -203,6 +205,7 @@ public class IpClientIntegrationTest {
		private class Dependencies extends IpClient.Dependencies {
		private boolean mIsDhcpLeaseCacheEnabled;
		private boolean mIsDhcpRapidCommitEnabled;
		private int mMtu = TEST_DEFAULT_MTU;

		public void setDhcpLeaseCacheEnabled(final boolean enable) {
		mIsDhcpLeaseCacheEnabled = enable;
		@@ -212,6 +215,10 @@ public class IpClientIntegrationTest {
		mIsDhcpRapidCommitEnabled = enable;
		}

		public void setMtu(final int mtu) {
		mMtu = mtu;
		}

		@Override
		public INetd getNetd(Context context) {
		return mNetd;
		@@ -242,6 +249,11 @@ public class IpClientIntegrationTest {
		}
		};
		}

		@Override
		public int getInterfaceMtu(String ifName) {
		return mMtu;
		}
		}

		@Before
		@@ -345,7 +357,7 @@ 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 +365,11 @@ 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 +377,7 @@ 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 +409,7 @@ 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 +428,7 @@ 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() {
		@@ -433,13 +445,16 @@ public class IpClientIntegrationTest {
		while ((packet = getNextDhcpPacket()) != null) {
		if (packet instanceof DhcpDiscoverPacket) {
		if (isDhcpRapidCommitEnabled) {
		sendResponse(buildDhcpAckPacket(packet, leaseTimeSec));
		sendResponse(buildDhcpAckPacket(packet, leaseTimeSec,
		(short) mDependencies.getInterfaceMtu(mIfaceName)));
		} else {
		sendResponse(buildDhcpOfferPacket(packet, leaseTimeSec));
		sendResponse(buildDhcpOfferPacket(packet, leaseTimeSec,
		(short) mDependencies.getInterfaceMtu(mIfaceName)));
		}
		} else if (packet instanceof DhcpRequestPacket) {
		final ByteBuffer byteBuffer = isSuccessLease
		? buildDhcpAckPacket(packet, leaseTimeSec)
		? buildDhcpAckPacket(packet, leaseTimeSec,
		(short) mDependencies.getInterfaceMtu(mIfaceName))
		: buildDhcpNakPacket(packet);
		sendResponse(byteBuffer);
		} else {
		@@ -487,7 +502,7 @@ public class IpClientIntegrationTest {
		final long currentTime = System.currentTimeMillis();
		performDhcpHandshake(true /* isSuccessLease */, TEST_LEASE_DURATION_S,
		true /* isDhcpLeaseCacheEnabled /, false / isDhcpRapidCommitEnabled */);
		assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime);
		assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, TEST_DEFAULT_MTU);
		}

		@Test
		@@ -502,7 +517,7 @@ public class IpClientIntegrationTest {
		final long currentTime = System.currentTimeMillis();
		performDhcpHandshake(true /* isSuccessLease */, INFINITE_LEASE,
		true /* isDhcpLeaseCacheEnabled /, false / isDhcpRapidCommitEnabled */);
		assertIpMemoryStoreNetworkAttributes(INFINITE_LEASE, currentTime);
		assertIpMemoryStoreNetworkAttributes(INFINITE_LEASE, currentTime, TEST_DEFAULT_MTU);
		}

		@Test
		@@ -510,7 +525,7 @@ public class IpClientIntegrationTest {
		final long currentTime = System.currentTimeMillis();
		performDhcpHandshake(true /* isSuccessLease /, null / no lease time */,
		true /* isDhcpLeaseCacheEnabled /, false / isDhcpRapidCommitEnabled */);
		assertIpMemoryStoreNetworkAttributes(null, currentTime);
		assertIpMemoryStoreNetworkAttributes(null, currentTime, TEST_DEFAULT_MTU);
		}

		@Test
		@@ -527,7 +542,7 @@ public class IpClientIntegrationTest {
		final long currentTime = System.currentTimeMillis();
		performDhcpHandshake(true /* isSuccessLease */, TEST_LEASE_DURATION_S,
		true /* isDhcpLeaseCacheEnabled /, true / isDhcpRapidCommitEnabled */);
		assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime);
		assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, TEST_DEFAULT_MTU);
		}

		@Test
		@@ -536,7 +551,7 @@ 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 +564,7 @@ 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 +583,7 @@ 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 +594,7 @@ 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 +608,23 @@ public class IpClientIntegrationTest {
		final DhcpPacket packet = getNextDhcpPacket();
		assertTrue(DhcpDiscoverPacket.class.isInstance(packet));
		}

		@Test
		public void testRestoreInitialInterfaceMtu() throws Exception {
		final long currentTime = System.currentTimeMillis();

		// check the initial interface MTU
		assertTrue(mDependencies.getInterfaceMtu(mIfaceName) == TEST_DEFAULT_MTU);

		// change the MTU and pass the new MTU into DHCPOFFER and DHCPACK packet
		mDependencies.setMtu(TEST_MIN_MTU);
		performDhcpHandshake(true /* isSuccessLease */, TEST_LEASE_DURATION_S,
		true /* isDhcpLeaseCacheEnabled /, false / isDhcpRapidCommitEnabled */);
		assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, TEST_MIN_MTU);

		mIpc.shutdown();
		HandlerUtilsKt.waitForIdle(mIpc.getHandler(), TEST_TIMEOUT_MS);
		// verify that mtu indeed has been restored
		verify(mNetd, times(1)).interfaceSetMtu(mIfaceName, TEST_DEFAULT_MTU);
		}
		}

tests/unit/src/android/net/ip/IpClientTest.java

+2 −0

Original line number	Diff line number	Diff line
		@@ -83,6 +83,7 @@ public class IpClientTest {
		private static final String INVALID = "INVALID";
		private static final String TEST_IFNAME = "test_wlan0";
		private static final int TEST_IFINDEX = 1001;
		private static final int TEST_MTU = 1500;
		// See RFC 7042#section-2.1.2 for EUI-48 documentation values.
		private static final MacAddress TEST_MAC = MacAddress.fromString("00:00:5E:00:53:01");
		private static final int TEST_TIMEOUT_MS = 400;
		@@ -122,6 +123,7 @@ public class IpClientTest {
		when(mDependencies.getInterfaceParams(any())).thenReturn(mInterfaceParams);
		when(mDependencies.getIpMemoryStore(mContext, mNetworkStackServiceManager))
		.thenReturn(mIpMemoryStore);
		when(mDependencies.getInterfaceMtu(TEST_IFNAME)).thenReturn(TEST_MTU);

		mIfParams = null;
		}