tests/integration/common/android/net/ip/IpClientIntegrationTestCommon.java

/*
 * Copyright (C) 2019 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.net.ip;

import static android.Manifest.permission.MANAGE_TEST_NETWORKS;
import static android.Manifest.permission.READ_DEVICE_CONFIG;
import static android.Manifest.permission.WRITE_DEVICE_CONFIG;
import static android.net.NetworkCapabilities.NET_CAPABILITY_INTERNET;
import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_RESTRICTED;
import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_ROAMING;
import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_SUSPENDED;
import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_VPN;
import static android.net.NetworkCapabilities.NET_CAPABILITY_TRUSTED;
import static android.net.NetworkCapabilities.TRANSPORT_TEST;
import static android.net.RouteInfo.RTN_UNICAST;
import static android.net.RouteInfo.RTN_UNREACHABLE;
import static android.net.dhcp.DhcpClient.EXPIRED_LEASE;
import static android.net.dhcp.DhcpPacket.DHCP_BOOTREQUEST;
import static android.net.dhcp.DhcpPacket.DHCP_CLIENT;
import static android.net.dhcp.DhcpPacket.DHCP_IPV6_ONLY_PREFERRED;
import static android.net.dhcp.DhcpPacket.DHCP_MAGIC_COOKIE;
import static android.net.dhcp.DhcpPacket.DHCP_SERVER;
import static android.net.dhcp.DhcpPacket.ENCAP_L2;
import static android.net.dhcp.DhcpPacket.INADDR_BROADCAST;
import static android.net.dhcp.DhcpPacket.INFINITE_LEASE;
import static android.net.dhcp.DhcpPacket.MIN_V6ONLY_WAIT_MS;
import static android.net.ip.IIpClientCallbacks.DTIM_MULTIPLIER_RESET;
import static android.net.ip.IpClient.CONFIG_IPV6_AUTOCONF_TIMEOUT;
import static android.net.ip.IpClient.CONFIG_ACCEPT_RA_MIN_LFT;
import static android.net.ip.IpClient.DEFAULT_ACCEPT_RA_MIN_LFT;
import static android.net.ip.IpClientLinkObserver.CLAT_PREFIX;
import static android.net.ip.IpClientLinkObserver.CONFIG_SOCKET_RECV_BUFSIZE;
import static android.net.ip.IpReachabilityMonitor.NUD_MCAST_RESOLICIT_NUM;
import static android.net.ip.IpReachabilityMonitor.nudEventTypeToInt;
import static android.net.ipmemorystore.Status.SUCCESS;
import static android.system.OsConstants.ETH_P_IPV6;
import static android.system.OsConstants.IFA_F_TEMPORARY;
import static android.system.OsConstants.IPPROTO_ICMPV6;
import static android.system.OsConstants.IPPROTO_IPV6;
import static android.system.OsConstants.IPPROTO_UDP;
import static com.android.net.module.util.Inet4AddressUtils.getBroadcastAddress;
import static com.android.net.module.util.Inet4AddressUtils.getPrefixMaskAsInet4Address;
import static com.android.net.module.util.NetworkStackConstants.ALL_DHCP_RELAY_AGENTS_AND_SERVERS;
import static com.android.net.module.util.NetworkStackConstants.ARP_REPLY;
import static com.android.net.module.util.NetworkStackConstants.ARP_REQUEST;
import static com.android.net.module.util.NetworkStackConstants.DHCP6_CLIENT_PORT;
import static com.android.net.module.util.NetworkStackConstants.DHCP6_SERVER_PORT;
import static com.android.net.module.util.NetworkStackConstants.ETHER_ADDR_LEN;
import static com.android.net.module.util.NetworkStackConstants.ETHER_BROADCAST;
import static com.android.net.module.util.NetworkStackConstants.ETHER_HEADER_LEN;
import static com.android.net.module.util.NetworkStackConstants.ETHER_TYPE_OFFSET;
import static com.android.net.module.util.NetworkStackConstants.ICMPV6_ND_OPTION_SLLA;
import static com.android.net.module.util.NetworkStackConstants.ICMPV6_NEIGHBOR_ADVERTISEMENT;
import static com.android.net.module.util.NetworkStackConstants.ICMPV6_NEIGHBOR_SOLICITATION;
import static com.android.net.module.util.NetworkStackConstants.ICMPV6_ROUTER_SOLICITATION;
import static com.android.net.module.util.NetworkStackConstants.IPV4_ADDR_ANY;
import static com.android.net.module.util.NetworkStackConstants.IPV6_ADDR_ALL_NODES_MULTICAST;
import static com.android.net.module.util.NetworkStackConstants.IPV6_ADDR_ALL_ROUTERS_MULTICAST;
import static com.android.net.module.util.NetworkStackConstants.IPV6_ADDR_ANY;
import static com.android.net.module.util.NetworkStackConstants.IPV6_PROTOCOL_OFFSET;
import static com.android.net.module.util.NetworkStackConstants.NEIGHBOR_ADVERTISEMENT_FLAG_OVERRIDE;
import static com.android.net.module.util.NetworkStackConstants.NEIGHBOR_ADVERTISEMENT_FLAG_ROUTER;
import static com.android.net.module.util.NetworkStackConstants.NEIGHBOR_ADVERTISEMENT_FLAG_SOLICITED;
import static com.android.net.module.util.NetworkStackConstants.PIO_FLAG_AUTONOMOUS;
import static com.android.net.module.util.NetworkStackConstants.PIO_FLAG_ON_LINK;
import static com.android.testutils.MiscAsserts.assertThrows;
import static com.android.testutils.ParcelUtils.parcelingRoundTrip;
import static com.android.testutils.TestPermissionUtil.runAsShell;
import static junit.framework.Assert.fail;
import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertTrue;
import static org.junit.Assume.assumeFalse;
import static org.junit.Assume.assumeTrue;
import static org.mockito.ArgumentMatchers.anyInt;
import static org.mockito.ArgumentMatchers.anyLong;
import static org.mockito.ArgumentMatchers.contains;
import static org.mockito.ArgumentMatchers.longThat;
import static org.mockito.Mockito.after;
import static org.mockito.Mockito.any;
import static org.mockito.Mockito.argThat;
import static org.mockito.Mockito.atLeastOnce;
import static org.mockito.Mockito.clearInvocations;
import static org.mockito.Mockito.doAnswer;
import static org.mockito.Mockito.doThrow;
import static org.mockito.Mockito.eq;
import static org.mockito.Mockito.inOrder;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.reset;
import static org.mockito.Mockito.spy;
import static org.mockito.Mockito.timeout;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

import android.app.AlarmManager;
import android.app.AlarmManager.OnAlarmListener;
import android.app.Instrumentation;
import android.app.UiAutomation;
import android.content.ContentResolver;
import android.content.Context;
import android.content.res.Resources;
import android.net.ConnectivityManager;
import android.net.DhcpResultsParcelable;
import android.net.INetd;
import android.net.InetAddresses;
import android.net.InterfaceConfigurationParcel;
import android.net.IpPrefix;
import android.net.Layer2InformationParcelable;
import android.net.Layer2PacketParcelable;
import android.net.LinkAddress;
import android.net.LinkProperties;
import android.net.MacAddress;
import android.net.Network;
import android.net.NetworkAgentConfig;
import android.net.NetworkCapabilities;
import android.net.NetworkRequest;
import android.net.NetworkSpecifier;
import android.net.NetworkStackIpMemoryStore;
import android.net.RouteInfo;
import android.net.TestNetworkInterface;
import android.net.TestNetworkManager;
import android.net.Uri;
import android.net.dhcp.DhcpClient;
import android.net.dhcp.DhcpDeclinePacket;
import android.net.dhcp.DhcpDiscoverPacket;
import android.net.dhcp.DhcpPacket;
import android.net.dhcp.DhcpPacket.ParseException;
import android.net.dhcp.DhcpRequestPacket;
import android.net.dhcp6.Dhcp6Client;
import android.net.dhcp6.Dhcp6Packet;
import android.net.dhcp6.Dhcp6RebindPacket;
import android.net.dhcp6.Dhcp6RenewPacket;
import android.net.dhcp6.Dhcp6RequestPacket;
import android.net.dhcp6.Dhcp6SolicitPacket;
import android.net.ipmemorystore.NetworkAttributes;
import android.net.ipmemorystore.OnNetworkAttributesRetrievedListener;
import android.net.ipmemorystore.Status;
import android.net.networkstack.TestNetworkStackServiceClient;
import android.net.networkstack.aidl.dhcp.DhcpOption;
import android.net.networkstack.aidl.ip.ReachabilityLossInfoParcelable;
import android.net.networkstack.aidl.ip.ReachabilityLossReason;
import android.net.shared.Layer2Information;
import android.net.shared.ProvisioningConfiguration;
import android.net.shared.ProvisioningConfiguration.ScanResultInfo;
import android.os.Build;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.IBinder;
import android.os.ParcelFileDescriptor;
import android.os.PowerManager;
import android.os.RemoteException;
import android.os.SystemClock;
import android.os.SystemProperties;
import android.provider.DeviceConfig;
import android.stats.connectivity.NudEventType;
import android.system.ErrnoException;
import android.system.Os;
import android.util.ArrayMap;

import androidx.annotation.NonNull;
import androidx.test.InstrumentationRegistry;
import androidx.test.filters.SmallTest;

import com.android.internal.util.HexDump;
import com.android.internal.util.StateMachine;
import com.android.net.module.util.ArrayTrackRecord;
import com.android.net.module.util.InterfaceParams;
import com.android.net.module.util.Ipv6Utils;
import com.android.net.module.util.PacketBuilder;
import com.android.net.module.util.SharedLog;
import com.android.net.module.util.Struct;
import com.android.net.module.util.arp.ArpPacket;
import com.android.net.module.util.ip.IpNeighborMonitor;
import com.android.net.module.util.ip.IpNeighborMonitor.NeighborEventConsumer;
import com.android.net.module.util.netlink.NetlinkUtils;
import com.android.net.module.util.netlink.StructNdOptPref64;
import com.android.net.module.util.structs.EthernetHeader;
import com.android.net.module.util.structs.Ipv6Header;
import com.android.net.module.util.structs.LlaOption;
import com.android.net.module.util.structs.PrefixInformationOption;
import com.android.net.module.util.structs.RdnssOption;
import com.android.networkstack.R;
import com.android.networkstack.apishim.CaptivePortalDataShimImpl;
import com.android.networkstack.apishim.ConstantsShim;
import com.android.networkstack.apishim.common.ShimUtils;
import com.android.networkstack.ipmemorystore.IpMemoryStoreService;
import com.android.networkstack.metrics.IpProvisioningMetrics;
import com.android.networkstack.metrics.IpReachabilityMonitorMetrics;
import com.android.networkstack.metrics.NetworkQuirkMetrics;
import com.android.networkstack.packets.NeighborAdvertisement;
import com.android.networkstack.packets.NeighborSolicitation;
import com.android.networkstack.util.NetworkStackUtils;
import com.android.server.NetworkObserver;
import com.android.server.NetworkObserverRegistry;
import com.android.server.NetworkStackService.NetworkStackServiceManager;
import com.android.testutils.CompatUtil;
import com.android.testutils.DevSdkIgnoreRule;
import com.android.testutils.DevSdkIgnoreRule.IgnoreAfter;
import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo;
import com.android.testutils.HandlerUtils;
import com.android.testutils.SkipPresubmit;
import com.android.testutils.TapPacketReader;
import com.android.testutils.TestableNetworkAgent;
import com.android.testutils.TestableNetworkCallback;

import kotlin.Lazy;
import kotlin.LazyKt;

import org.junit.After;
import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.TestName;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
import org.mockito.ArgumentCaptor;
import org.mockito.InOrder;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import org.mockito.Spy;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileDescriptor;
import java.io.FileReader;
import java.io.IOException;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Method;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Objects;
import java.util.Random;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Predicate;

/**
 * Base class for IpClient tests.
 *
 * Tests in this class can either be run with signature permissions, or with root access.
 */
@RunWith(Parameterized.class)
@SmallTest
public abstract class IpClientIntegrationTestCommon {
    private static final int DATA_BUFFER_LEN = 4096;
    private static final int PACKET_TIMEOUT_MS = 5_000;
    private static final String TEST_CLUSTER = "some cluster";
    private static final int TEST_LEASE_DURATION_S = 3_600; // 1 hour
    private static final int TEST_IPV6_ONLY_WAIT_S = 1_800; // 30 min
    private static final int TEST_LOWER_IPV6_ONLY_WAIT_S = (int) (MIN_V6ONLY_WAIT_MS / 1000 - 1);
    private static final int TEST_ZERO_IPV6_ONLY_WAIT_S = 0;
    private static final long TEST_MAX_IPV6_ONLY_WAIT_S = 0xffffffffL;
    protected static final String TEST_L2KEY = "some l2key";

    // TODO: move to NetlinkConstants, NetworkStackConstants, or OsConstants.
    private static final int IFA_F_STABLE_PRIVACY = 0x800;

    protected static final long TEST_TIMEOUT_MS = 2_000L;
    private static final long TEST_WAIT_ENOBUFS_TIMEOUT_MS = 30_000L;

    @Rule
    public final DevSdkIgnoreRule mIgnoreRule = new DevSdkIgnoreRule();
    @Rule
    public final TestName mTestNameRule = new TestName();

    // Indicate whether the flag of parsing netlink event is enabled or not. If it's disabled,
    // integration test still covers the old codepath(i.e. using NetworkObserver), otherwise,
    // test goes through the new codepath(i.e. processRtNetlinkxxx).
    @Parameterized.Parameter(0)
    public boolean mIsNetlinkEventParseEnabled;

    @Parameterized.Parameters
    public static Iterable<? extends Object> data() {
        return Arrays.asList(Boolean.FALSE, Boolean.TRUE);
    }

    /**
     * Indicates that a test requires signature permissions to run.
     *
     * Such tests can only be run on devices that use known signing keys, so this annotation must be
     * avoided as much as possible. Consider whether the test can be written to use shell and root
     * shell permissions, and run against the NetworkStack AIDL interface (IIpClient) instead.
     */
    @Retention(RetentionPolicy.RUNTIME)
    @Target({ElementType.METHOD})
    private @interface SignatureRequiredTest {
        String reason();
    }

    /**** BEGIN signature required test members ****/
    // Do not use unless the test *really* cannot be written to exercise IIpClient without mocks.
    // Tests using the below members must be annotated with @SignatureRequiredTest (otherwise the
    // members will be null), and can only be run on devices that use known signing keys.
    // The members could technically be moved to the IpClientIntegrationTest subclass together with
    // the tests requiring signature permissions, but this would make it harder to follow tests in
    // multiple classes, and harder to migrate tests between signature required and not required.

    @Mock private Context mContext;
    @Mock private ConnectivityManager mCm;
    @Mock private Resources mResources;
    @Mock private AlarmManager mAlarm;
    @Mock private ContentResolver mContentResolver;
    @Mock private NetworkStackServiceManager mNetworkStackServiceManager;
    @Mock private IpMemoryStoreService mIpMemoryStoreService;
    @Mock private PowerManager.WakeLock mTimeoutWakeLock;
    @Mock protected NetworkStackIpMemoryStore mIpMemoryStore;
    @Mock private NetworkQuirkMetrics.Dependencies mNetworkQuirkMetricsDeps;
    @Mock private IpReachabilityMonitorMetrics mIpReachabilityMonitorMetrics;

    @Spy private INetd mNetd;
    private NetworkObserverRegistry mNetworkObserverRegistry;

    protected IpClient mIpc;
    protected Dependencies mDependencies;

    /***** END signature required test members *****/

    protected IIpClientCallbacks mCb;
    private IIpClient mIIpClient;
    private String mIfaceName;
    private HandlerThread mPacketReaderThread;
    private Handler mHandler;
    private TapPacketReader mPacketReader;
    private FileDescriptor mTapFd;
    private byte[] mClientMac;
    private InetAddress mClientIpAddress;
    private TestableNetworkAgent mNetworkAgent;
    private HandlerThread mNetworkAgentThread;

    private boolean mIsSignatureRequiredTest;

    // ReadHeads for various packet streams. Cannot be initialized in @Before because ReadHead is
    // single-thread-only, and AndroidJUnitRunner runs @Before and @Test on different threads.
    // While it looks like these are created only once per test, they are actually created once per
    // test method because JUnit recreates a fresh test class instance before every test method.
    private Lazy<ArrayTrackRecord<byte[]>.ReadHead> mDhcpPacketReadHead =
            LazyKt.lazy(() -> mPacketReader.getReceivedPackets().newReadHead());
    private Lazy<ArrayTrackRecord<byte[]>.ReadHead> mArpPacketReadHead =
            LazyKt.lazy(() -> mPacketReader.getReceivedPackets().newReadHead());
    private Lazy<ArrayTrackRecord<byte[]>.ReadHead> mDhcp6PacketReadHead =
            LazyKt.lazy(() -> mPacketReader.getReceivedPackets().newReadHead());

    // Ethernet header
    private static final int ETH_HEADER_LEN = 14;

    // IP header
    private static final int IPV4_HEADER_LEN = 20;
    private static final int IPV6_HEADER_LEN = 40;
    private static final int IPV4_SRC_ADDR_OFFSET = ETH_HEADER_LEN + 12;
    private static final int IPV4_DST_ADDR_OFFSET = IPV4_SRC_ADDR_OFFSET + 4;

    // UDP header
    private static final int UDP_HEADER_LEN = 8;
    private static final int UDP_HEADER_OFFSET = ETH_HEADER_LEN + IPV4_HEADER_LEN;
    private static final int UDP_SRC_PORT_OFFSET = UDP_HEADER_OFFSET + 0;

    // DHCP header
    private static final int DHCP_HEADER_OFFSET = ETH_HEADER_LEN + IPV4_HEADER_LEN
            + UDP_HEADER_LEN;
    private static final int DHCP_MESSAGE_OP_CODE_OFFSET = DHCP_HEADER_OFFSET + 0;
    private static final int DHCP_TRANSACTION_ID_OFFSET = DHCP_HEADER_OFFSET + 4;
    private static final int DHCP_OPTION_MAGIC_COOKIE_OFFSET = DHCP_HEADER_OFFSET + 236;

    // DHCPv6 header
    private static final int DHCP6_HEADER_OFFSET = ETH_HEADER_LEN + IPV6_HEADER_LEN
            + UDP_HEADER_LEN;

    private static final Inet4Address SERVER_ADDR =
            (Inet4Address) InetAddresses.parseNumericAddress("192.168.1.100");
    private static final Inet4Address CLIENT_ADDR =
            (Inet4Address) InetAddresses.parseNumericAddress("192.168.1.2");
    private static final Inet4Address CLIENT_ADDR_NEW =
            (Inet4Address) InetAddresses.parseNumericAddress("192.168.1.3");
    private static final Inet4Address INADDR_ANY =
            (Inet4Address) InetAddresses.parseNumericAddress("0.0.0.0");
    private static final int PREFIX_LENGTH = 24;
    private static final Inet4Address NETMASK = getPrefixMaskAsInet4Address(PREFIX_LENGTH);
    private static final Inet4Address BROADCAST_ADDR = getBroadcastAddress(
            SERVER_ADDR, PREFIX_LENGTH);
    private static final String IPV6_LINK_LOCAL_PREFIX = "fe80::/64";
    private static final String IPV4_TEST_SUBNET_PREFIX = "192.168.1.0/24";
    private static final String IPV4_ANY_ADDRESS_PREFIX = "0.0.0.0/0";
    private static final String HOSTNAME = "testhostname";
    private static final String IPV6_OFF_LINK_DNS_SERVER = "2001:4860:4860::64";
    private static final String IPV6_ON_LINK_DNS_SERVER = "2001:db8:1::64";
    private static final int TEST_DEFAULT_MTU = 1500;
    private static final int TEST_MIN_MTU = 1280;
    private static final MacAddress ROUTER_MAC = MacAddress.fromString("00:1A:11:22:33:44");
    private static final byte[] ROUTER_MAC_BYTES = ROUTER_MAC.toByteArray();
    private static final Inet6Address ROUTER_LINK_LOCAL =
                (Inet6Address) InetAddresses.parseNumericAddress("fe80::1");
    private static final byte[] ROUTER_DUID = new byte[] {
            // type: Link-layer address, hardware type: EUI64(27)
            (byte) 0x00, (byte) 0x03, (byte) 0x00, (byte) 0x1b,
            // set 7th bit, and copy the first 3 bytes of mac address
            (byte) 0x02, (byte) 0x1A, (byte) 0x11,
            (byte) 0xFF, (byte) 0xFE,
            // copy the last 3 bytes of mac address
            (byte) 0x22, (byte) 0x33, (byte) 0x44,
    };
    private static final String TEST_HOST_NAME = "AOSP on Crosshatch";
    private static final String TEST_HOST_NAME_TRANSLITERATION = "AOSP-on-Crosshatch";
    private static final String TEST_CAPTIVE_PORTAL_URL = "https://example.com/capportapi";
    private static final byte[] TEST_HOTSPOT_OUI = new byte[] {
            (byte) 0x00, (byte) 0x17, (byte) 0xF2
    };
    private static final byte TEST_VENDOR_SPECIFIC_TYPE = 0x06;

    private static final String TEST_DEFAULT_SSID = "test_ssid";
    private static final String TEST_DEFAULT_BSSID = "00:11:22:33:44:55";
    private static final String TEST_DHCP_ROAM_SSID = "0001docomo";
    private static final String TEST_DHCP_ROAM_BSSID = "00:4e:35:17:98:55";
    private static final String TEST_DHCP_ROAM_L2KEY = "roaming_l2key";
    private static final String TEST_DHCP_ROAM_CLUSTER = "roaming_cluster";
    private static final byte[] TEST_AP_OUI = new byte[] { 0x00, 0x1A, 0x11 };
    private static final byte[] TEST_OEM_OUI = new byte[] {(byte) 0x00, (byte) 0x17, (byte) 0xc3};
    private static final String TEST_OEM_VENDOR_ID = "vendor-class-identifier";
    private static final byte[] TEST_OEM_USER_CLASS_INFO = new byte[] {
            // Instance of User Class: [0]
            (byte) 0x03, /* UC_Len_0 */ (byte) 0x11, (byte) 0x22, (byte) 0x33,
            // Instance of User Class: [1]
            (byte) 0x03, /* UC_Len_1 */ (byte) 0x44, (byte) 0x55, (byte) 0x66,
    };

    protected class Dependencies extends IpClient.Dependencies {
        // Can't use SparseIntArray, it doesn't have an easy way to know if a key is not present.
        private HashMap<String, Integer> mIntConfigProperties = new HashMap<>();
        private DhcpClient mDhcpClient;
        private Dhcp6Client mDhcp6Client;
        private boolean mIsHostnameConfigurationEnabled;
        private String mHostname;
        private boolean mIsInterfaceRecovered;

        public void setHostnameConfiguration(final boolean enable, final String hostname) {
            mIsHostnameConfigurationEnabled = enable;
            mHostname = hostname;
        }

        // Enable this flag to simulate the interface has been added back after removing
        // on the provisioning start. However, the actual tap interface has been removed,
        // interface parameters query will get null when attempting to restore Interface
        // MTU. Create a new InterfaceParams instance and return instead just for interface
        // toggling test case.
        public void simulateInterfaceRecover() {
            mIsInterfaceRecovered = true;
        }

        @Override
        public InterfaceParams getInterfaceParams(String ifname) {
            return mIsInterfaceRecovered
                    ? new InterfaceParams(ifname, 1 /* index */,
                            MacAddress.fromString("00:11:22:33:44:55"))
                    : super.getInterfaceParams(ifname);
        }

        @Override
        public INetd getNetd(Context context) {
            return mNetd;
        }

        @Override
        public NetworkStackIpMemoryStore getIpMemoryStore(Context context,
                NetworkStackServiceManager nssManager) {
            return mIpMemoryStore;
        }

        @Override
        public DhcpClient makeDhcpClient(Context context, StateMachine controller,
                InterfaceParams ifParams, DhcpClient.Dependencies deps) {
            mDhcpClient = DhcpClient.makeDhcpClient(context, controller, ifParams, deps);
            return mDhcpClient;
        }

        @Override
        public Dhcp6Client makeDhcp6Client(Context context, StateMachine controller,
                InterfaceParams ifParams, Dhcp6Client.Dependencies deps) {
            mDhcp6Client = Dhcp6Client.makeDhcp6Client(context, controller, ifParams, deps);
            return mDhcp6Client;
        }

        @Override
        public IpReachabilityMonitor getIpReachabilityMonitor(Context context,
                InterfaceParams ifParams, Handler h, SharedLog log,
                IpReachabilityMonitor.Callback callback, boolean usingMultinetworkPolicyTracker,
                IpReachabilityMonitor.Dependencies deps, final INetd netd) {
            return new IpReachabilityMonitor(context, ifParams, h, log, callback,
                    usingMultinetworkPolicyTracker, deps, netd);
        }

        @Override
        public boolean isFeatureEnabled(final Context context, final String name,
                final boolean defaultEnabled) {
            return IpClientIntegrationTestCommon.this.isFeatureEnabled(name, defaultEnabled);
        }

        @Override
        public Dhcp6Client.Dependencies getDhcp6ClientDependencies() {
            return new Dhcp6Client.Dependencies() {
                @Override
                public int getDeviceConfigPropertyInt(String name, int defaultValue) {
                    return Dependencies.this.getDeviceConfigPropertyInt(name,
                            0 /* default value */);
                }
            };
        }

        @Override
        public DhcpClient.Dependencies getDhcpClientDependencies(
                NetworkStackIpMemoryStore ipMemoryStore, IpProvisioningMetrics metrics) {
            return new DhcpClient.Dependencies(ipMemoryStore, metrics) {
                @Override
                public boolean isFeatureEnabled(final Context context, final String name,
                        final boolean defaultEnabled) {
                    return Dependencies.this.isFeatureEnabled(context, name, defaultEnabled);
                }

                @Override
                public int getIntDeviceConfig(final String name, int minimumValue,
                        int maximumValue, int defaultValue) {
                    return getDeviceConfigPropertyInt(name, 0 /* default value */);
                }

                @Override
                public PowerManager.WakeLock getWakeLock(final PowerManager powerManager) {
                    return mTimeoutWakeLock;
                }

                @Override
                public boolean getSendHostnameOption(final Context context) {
                    return mIsHostnameConfigurationEnabled;
                }

                @Override
                public String getDeviceName(final Context context) {
                    return mIsHostnameConfigurationEnabled ? mHostname : null;
                }
            };
        }

        @Override
        public IpReachabilityMonitor.Dependencies getIpReachabilityMonitorDeps(Context context,
                String name) {
            return new IpReachabilityMonitor.Dependencies() {
                public void acquireWakeLock(long durationMs) {
                    // It doesn't matter for the integration test app on whether the wake lock
                    // is acquired or not.
                    return;
                }

                public IpNeighborMonitor makeIpNeighborMonitor(Handler h, SharedLog log,
                        NeighborEventConsumer cb) {
                    return new IpNeighborMonitor(h, log, cb);
                }

                public boolean isFeatureEnabled(final Context context, final String name,
                        boolean defaultEnabled) {
                    return Dependencies.this.isFeatureEnabled(context, name, defaultEnabled);
                }

                public IpReachabilityMonitorMetrics getIpReachabilityMonitorMetrics() {
                    return mIpReachabilityMonitorMetrics;
                }
            };
        }

        @Override
        public int getDeviceConfigPropertyInt(String name, int defaultValue) {
            Integer value = mIntConfigProperties.get(name);
            if (value == null) {
                throw new IllegalStateException("Non-mocked device config property " + name);
            }
            return value;
        }

        public void setDeviceConfigProperty(String name, int value) {
            mIntConfigProperties.put(name, value);
        }

        @Override
        public NetworkQuirkMetrics getNetworkQuirkMetrics() {
            return new NetworkQuirkMetrics(mNetworkQuirkMetricsDeps);
        }
    }

    @NonNull
    protected abstract IIpClient makeIIpClient(
            @NonNull String ifaceName, @NonNull IIpClientCallbacks cb);

    protected abstract void setFeatureEnabled(String name, boolean enabled);

    protected abstract boolean isFeatureEnabled(String name, boolean defaultEnabled);

    protected abstract boolean useNetworkStackSignature();

    protected abstract NetworkAttributes getStoredNetworkAttributes(String l2Key, long timeout);

    protected abstract void storeNetworkAttributes(String l2Key, NetworkAttributes na);

    protected abstract void assertIpMemoryNeverStoreNetworkAttributes(String l2Key, long timeout);

    protected abstract int readNudSolicitNumInSteadyStateFromResource();

    protected abstract int readNudSolicitNumPostRoamingFromResource();

    protected final boolean testSkipped() {
        if (!useNetworkStackSignature() && !TestNetworkStackServiceClient.isSupported()) {
            fail("Device running root tests doesn't support TestNetworkStackServiceClient.");
        }
        return !useNetworkStackSignature() && mIsSignatureRequiredTest;
    }

    private ArrayMap<String, String> mOriginalPropertyValues = new ArrayMap<>();

    protected void setDeviceConfigProperty(String name, String value) {
        final UiAutomation am = InstrumentationRegistry.getInstrumentation().getUiAutomation();
        am.adoptShellPermissionIdentity(READ_DEVICE_CONFIG, WRITE_DEVICE_CONFIG);
        try {
            // Do not use computeIfAbsent as it would overwrite null values,
            // property originally unset.
            if (!mOriginalPropertyValues.containsKey(name)) {
                mOriginalPropertyValues.put(name,
                        DeviceConfig.getProperty(DeviceConfig.NAMESPACE_CONNECTIVITY, name));
            }
            DeviceConfig.setProperty(DeviceConfig.NAMESPACE_CONNECTIVITY, name, value,
                    false /* makeDefault */);
        } finally {
            am.dropShellPermissionIdentity();
        }
    }

    protected void setDeviceConfigProperty(String name, int value) {
        setDeviceConfigProperty(name, Integer.toString(value));
    }

    private void setFeatureChickenedOut(String name, boolean chickenedOut) {
        setDeviceConfigProperty(name, chickenedOut ? "1" : "0");
    }

    protected void setDhcpFeatures(final boolean isDhcpLeaseCacheEnabled,
            final boolean isRapidCommitEnabled, final boolean isDhcpIpConflictDetectEnabled,
            final boolean isIPv6OnlyPreferredEnabled) {
        setFeatureEnabled(NetworkStackUtils.DHCP_INIT_REBOOT_VERSION, isDhcpLeaseCacheEnabled);
        setFeatureEnabled(NetworkStackUtils.DHCP_RAPID_COMMIT_VERSION, isRapidCommitEnabled);
        setFeatureEnabled(NetworkStackUtils.DHCP_IP_CONFLICT_DETECT_VERSION,
                isDhcpIpConflictDetectEnabled);
        setFeatureEnabled(NetworkStackUtils.DHCP_IPV6_ONLY_PREFERRED_VERSION,
                isIPv6OnlyPreferredEnabled);
    }

    private void setDeviceConfigForMaxDtimMultiplier() {
        setDeviceConfigProperty(IpClient.CONFIG_INITIAL_PROVISIONING_DTIM_DELAY_MS,
                500 /* default value */);
        setDeviceConfigProperty(IpClient.CONFIG_MULTICAST_LOCK_MAX_DTIM_MULTIPLIER,
                IpClient.DEFAULT_MULTICAST_LOCK_MAX_DTIM_MULTIPLIER);
        setDeviceConfigProperty(IpClient.CONFIG_IPV6_ONLY_NETWORK_MAX_DTIM_MULTIPLIER,
                IpClient.DEFAULT_IPV6_ONLY_NETWORK_MAX_DTIM_MULTIPLIER);
        setDeviceConfigProperty(IpClient.CONFIG_IPV4_ONLY_NETWORK_MAX_DTIM_MULTIPLIER,
                IpClient.DEFAULT_IPV4_ONLY_NETWORK_MAX_DTIM_MULTIPLIER);
        setDeviceConfigProperty(IpClient.CONFIG_DUAL_STACK_MAX_DTIM_MULTIPLIER,
                IpClient.DEFAULT_DUAL_STACK_MAX_DTIM_MULTIPLIER);
        setDeviceConfigProperty(IpClient.CONFIG_BEFORE_IPV6_PROV_MAX_DTIM_MULTIPLIER,
                IpClient.DEFAULT_BEFORE_IPV6_PROV_MAX_DTIM_MULTIPLIER);
    }

    @Before
    public void setUp() throws Exception {
        // Suffix "[0]" or "[1]" is added to the end of test method name after running with
        // Parameterized.class, that's intended behavior, to iterate each test method with the
        // parameterize value. However, Class#getMethod() throws NoSuchMethodException when
        // searching the target test method name due to this change. Just keep the original test
        // method name to fix NoSuchMethodException, and find the correct annotation associated
        // to test method.
        final String testMethodName = mTestNameRule.getMethodName().split("\\[")[0];
        final Method testMethod = IpClientIntegrationTestCommon.class.getMethod(testMethodName);
        mIsSignatureRequiredTest = testMethod.getAnnotation(SignatureRequiredTest.class) != null;
        assumeFalse(testSkipped());

        // Depend on the parameterized value to enable/disable netlink message refactor flag.
        // Make sure both of the old codepath(rely on the INetdUnsolicitedEventListener aidl)
        // and new codepath(parse netlink event from kernel) will be executed.
        //
        // Note this must be called before making IpClient instance since MyNetlinkMontior ctor
        // in IpClientLinkObserver will use mIsNetlinkEventParseEnabled to decide the proper
        // bindGroups, otherwise, the parameterized value got from ArrayMap(integration test) is
        // always false.
        //
        // Set feature kill switch flag with the parameterized value to keep running test cases on
        // both code paths. Once we clean up the old code path (i.e.when the parameterized variable
        // is false), then we can also delete this code.
        setFeatureChickenedOut(NetworkStackUtils.IPCLIENT_PARSE_NETLINK_EVENTS_FORCE_DISABLE,
                !mIsNetlinkEventParseEnabled);

        // Enable DHCPv6 Prefix Delegation.
        setFeatureEnabled(NetworkStackUtils.IPCLIENT_DHCPV6_PREFIX_DELEGATION_VERSION,
                true /* isDhcp6PrefixDelegationEnabled */);

        setUpTapInterface();
        // It turns out that Router Solicitation will also be sent out even after the tap interface
        // is brought up, however, we want to wait for RS which is sent due to IPv6 stack is enabled
        // in the test code. The early RS might bring kind of race, for example, the IPv6 stack has
        // not been enabled when test code sees the RS, then kernel will not process RA even if we
        // replies immediately after receiving RS. Always waiting for the first RS show up after
        // interface is brought up helps prevent the race.
        waitForRouterSolicitation();

        mCb = mock(IIpClientCallbacks.class);
        if (useNetworkStackSignature()) {
            setUpMocks();
            setUpIpClient();
            // Enable packet retransmit alarm in DhcpClient.
            enableRealAlarm("DhcpClient." + mIfaceName + ".KICK");
            // Enable alarm for IPv6 autoconf via SLAAC in IpClient.
            enableRealAlarm("IpClient." + mIfaceName + ".EVENT_IPV6_AUTOCONF_TIMEOUT");
        }

        mIIpClient = makeIIpClient(mIfaceName, mCb);

        // Enable multicast filtering after creating IpClient instance, make the integration test
        // more realistic.
        mIIpClient.setMulticastFilter(true);
        setDeviceConfigForMaxDtimMultiplier();
        // Set IPv6 autoconf timeout. For signature tests, it has disabled the provisioning delay,
        // use a small timeout value to speed up the test execution; For root tests, we have to
        // wait a bit longer to make sure that we do see the success IPv6 provisioning, otherwise,
        // the global IPv6 address may show up later due to DAD, so we consider that autoconf fails
        // in this case and start DHCPv6 Prefix Delegation then.
        final int timeout = useNetworkStackSignature() ? 500 : (int) TEST_TIMEOUT_MS;
        setDeviceConfigProperty(IpClient.CONFIG_IPV6_AUTOCONF_TIMEOUT, timeout /* default value */);
    }

    protected void setUpMocks() throws Exception {
        MockitoAnnotations.initMocks(this);

        mDependencies = new Dependencies();
        when(mContext.getSystemService(eq(Context.ALARM_SERVICE))).thenReturn(mAlarm);
        when(mContext.getSystemService(eq(ConnectivityManager.class))).thenReturn(mCm);
        when(mContext.getResources()).thenReturn(mResources);
        when(mResources.getInteger(eq(R.integer.config_nud_postroaming_solicit_num))).thenReturn(5);
        when(mResources.getInteger(eq(R.integer.config_nud_postroaming_solicit_interval)))
                 .thenReturn(750);
        when(mResources.getInteger(eq(R.integer.config_nud_steadystate_solicit_num)))
                 .thenReturn(10);
        when(mResources.getInteger(eq(R.integer.config_nud_steadystate_solicit_interval)))
                 .thenReturn(750);
        when(mContext.getContentResolver()).thenReturn(mContentResolver);
        when(mNetworkStackServiceManager.getIpMemoryStoreService())
                .thenReturn(mIpMemoryStoreService);
        when(mCb.getInterfaceVersion()).thenReturn(IpClient.VERSION_ADDED_REACHABILITY_FAILURE);
        // This mock is required, otherwise, ignoreIPv6ProvisioningLoss variable is always true,
        // and IpReachabilityMonitor#avoidingBadLinks() will always return false as well, that
        // results in the target tested IPv6 off-link DNS server won't be removed from LP and
        // notifyLost won't be invoked, or the wrong code path when receiving RA with 0 router
        // liftime.
        when(mCm.shouldAvoidBadWifi()).thenReturn(true);

        mDependencies.setDeviceConfigProperty(IpClient.CONFIG_MIN_RDNSS_LIFETIME, 67);
        mDependencies.setDeviceConfigProperty(DhcpClient.DHCP_RESTART_CONFIG_DELAY, 10);
        mDependencies.setDeviceConfigProperty(DhcpClient.ARP_FIRST_PROBE_DELAY_MS, 10);
        mDependencies.setDeviceConfigProperty(DhcpClient.ARP_PROBE_MIN_MS, 10);
        mDependencies.setDeviceConfigProperty(DhcpClient.ARP_PROBE_MAX_MS, 20);
        mDependencies.setDeviceConfigProperty(DhcpClient.ARP_FIRST_ANNOUNCE_DELAY_MS, 10);
        mDependencies.setDeviceConfigProperty(DhcpClient.ARP_ANNOUNCE_INTERVAL_MS, 10);

        // Set the initial netlink socket receive buffer size to a minimum of 100KB to ensure test
        // cases are still working, meanwhile in order to easily overflow the receive buffer by
        // sending as few RAs as possible for test case where it's used to verify ENOBUFS.
        mDependencies.setDeviceConfigProperty(CONFIG_SOCKET_RECV_BUFSIZE, 100 * 1024);

        // Set the timeout to wait IPv6 autoconf to complete.
        mDependencies.setDeviceConfigProperty(CONFIG_IPV6_AUTOCONF_TIMEOUT, 500);

        // Set the minimal RA lifetime value, any RA section with liftime below this value will be
        // ignored.
        mDependencies.setDeviceConfigProperty(CONFIG_ACCEPT_RA_MIN_LFT, DEFAULT_ACCEPT_RA_MIN_LFT);
    }

    private void awaitIpClientShutdown() throws Exception {
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onQuit();
    }

    @After
    public void tearDown() throws Exception {
        if (testSkipped()) return;
        if (mNetworkAgent != null) {
            mNetworkAgent.unregister();
        }
        if (mNetworkAgentThread != null) {
            mNetworkAgentThread.quitSafely();
            mNetworkAgentThread.join();
        }
        teardownTapInterface();
        mIIpClient.shutdown();
        awaitIpClientShutdown();
    }

    @After
    public void tearDownDeviceConfigProperties() {
        if (testSkipped()) return;
        final UiAutomation am = InstrumentationRegistry.getInstrumentation().getUiAutomation();
        am.adoptShellPermissionIdentity(READ_DEVICE_CONFIG, WRITE_DEVICE_CONFIG);
        try {
            for (String key : mOriginalPropertyValues.keySet()) {
                if (key == null) continue;
                DeviceConfig.setProperty(DeviceConfig.NAMESPACE_CONNECTIVITY, key,
                        mOriginalPropertyValues.get(key), false /* makeDefault */);
            }
        } finally {
            am.dropShellPermissionIdentity();
        }
    }

    private void setUpTapInterface() throws Exception {
        final Instrumentation inst = InstrumentationRegistry.getInstrumentation();
        final TestNetworkInterface iface = runAsShell(MANAGE_TEST_NETWORKS, () -> {
            final TestNetworkManager tnm =
                    inst.getContext().getSystemService(TestNetworkManager.class);
            try {
                return tnm.createTapInterface(true /* carrierUp */, true /* bringUp */,
                        true /* disableIpv6ProvisioningDelay */);
            } catch (NoSuchMethodError e) {
                // createTapInterface(boolean, boolean, boolean) has been introduced since T,
                // use the legancy API if the method is not found on previous platforms.
                return tnm.createTapInterface();
            }
        });
        mIfaceName = iface.getInterfaceName();
        mClientMac = getIfaceMacAddr(mIfaceName).toByteArray();
        mPacketReaderThread = new HandlerThread(
                IpClientIntegrationTestCommon.class.getSimpleName());
        mPacketReaderThread.start();
        mHandler = mPacketReaderThread.getThreadHandler();

        // Detach the FileDescriptor from the ParcelFileDescriptor.
        // Otherwise, the garbage collector might call the ParcelFileDescriptor's finalizer, which
        // closes the FileDescriptor and destroys our tap interface. An alternative would be to
        // make the ParcelFileDescriptor or the TestNetworkInterface a class member so they never
        // go out of scope.
        mTapFd = new FileDescriptor();
        mTapFd.setInt$(iface.getFileDescriptor().detachFd());
        mPacketReader = new TapPacketReader(mHandler, mTapFd, DATA_BUFFER_LEN);
        mHandler.post(() -> mPacketReader.start());
    }

    private TestNetworkInterface setUpClatInterface(@NonNull String baseIface) throws Exception {
        final Instrumentation inst = InstrumentationRegistry.getInstrumentation();
        final TestNetworkInterface iface = runAsShell(MANAGE_TEST_NETWORKS, () -> {
            final TestNetworkManager tnm =
                    inst.getContext().getSystemService(TestNetworkManager.class);
            return tnm.createTapInterface(false /* bringUp */, CLAT_PREFIX + baseIface);
        });
        return iface;
    }

    private void teardownTapInterface() throws Exception {
        if (mPacketReader != null) {
            mHandler.post(() -> mPacketReader.stop());  // Also closes the socket
            mTapFd = null;
        }
        if (mPacketReaderThread != null) {
            mPacketReaderThread.quitSafely();
            mPacketReaderThread.join();
        }
    }

    private MacAddress getIfaceMacAddr(String ifaceName) throws IOException {
        // InterfaceParams.getByName requires CAP_NET_ADMIN: read the mac address with the shell
        final String strMacAddr = getOneLineCommandOutput(
                "su root cat /sys/class/net/" + ifaceName + "/address");
        return MacAddress.fromString(strMacAddr);
    }

    private String getOneLineCommandOutput(String cmd) throws IOException {
        try (ParcelFileDescriptor fd = InstrumentationRegistry.getInstrumentation()
                .getUiAutomation().executeShellCommand(cmd);
             BufferedReader reader = new BufferedReader(new FileReader(fd.getFileDescriptor()))) {
            return reader.readLine();
        }
    }

    private void enableRealAlarm(String cmdName) {
        doAnswer((inv) -> {
            final Context context = InstrumentationRegistry.getTargetContext();
            final AlarmManager alarmManager = context.getSystemService(AlarmManager.class);
            alarmManager.setExact(inv.getArgument(0), inv.getArgument(1), inv.getArgument(2),
                    inv.getArgument(3), inv.getArgument(4));
            return null;
        }).when(mAlarm).setExact(anyInt(), anyLong(), eq(cmdName), any(OnAlarmListener.class),
                any(Handler.class));
    }

    private IpClient makeIpClient() throws Exception {
        IpClient ipc = new IpClient(mContext, mIfaceName, mCb, mNetworkObserverRegistry,
                mNetworkStackServiceManager, mDependencies);
        // Wait for IpClient to enter its initial state. Otherwise, additional setup steps or tests
        // that mock IpClient's dependencies might interact with those mocks while IpClient is
        // starting. This would cause UnfinishedStubbingExceptions as mocks cannot be interacted
        // with while they are being stubbed.
        HandlerUtils.waitForIdle(ipc.getHandler(), TEST_TIMEOUT_MS);
        return ipc;
    }

    private void setUpIpClient() throws Exception {
        final Instrumentation inst = InstrumentationRegistry.getInstrumentation();
        final IBinder netdIBinder =
                (IBinder) inst.getContext().getSystemService(Context.NETD_SERVICE);
        mNetd = spy(INetd.Stub.asInterface(netdIBinder));
        when(mContext.getSystemService(eq(Context.NETD_SERVICE))).thenReturn(netdIBinder);
        assertNotNull(mNetd);

        mNetworkObserverRegistry = new NetworkObserverRegistry();
        mNetworkObserverRegistry.register(mNetd);
        mIpc = makeIpClient();

        // Tell the IpMemoryStore immediately to answer any question about network attributes with a
        // null response. Otherwise, the DHCP client will wait for two seconds before starting,
        // while its query to the IpMemoryStore times out.
        // This does not affect any test that makes the mock memory store return results, because
        // unlike when(), it is documented that doAnswer() can be called more than once, to change
        // the behaviour of a mock in the middle of a test.
        doAnswer(invocation -> {
            final String l2Key = invocation.getArgument(0);
            ((OnNetworkAttributesRetrievedListener) invocation.getArgument(1))
                    .onNetworkAttributesRetrieved(new Status(SUCCESS), l2Key, null);
            return null;
        }).when(mIpMemoryStore).retrieveNetworkAttributes(any(), any());

        disableIpv6ProvisioningDelays();
    }

    private <T> T verifyWithTimeout(InOrder inOrder, T t) {
        if (inOrder != null) {
            return inOrder.verify(t, timeout(TEST_TIMEOUT_MS));
        } else {
            return verify(t, timeout(TEST_TIMEOUT_MS));
        }
    }

    private void expectAlarmCancelled(InOrder inOrder, OnAlarmListener listener) {
        inOrder.verify(mAlarm, timeout(TEST_TIMEOUT_MS)).cancel(eq(listener));
    }

    private OnAlarmListener expectAlarmSet(InOrder inOrder, String tagMatch, long afterSeconds,
            Handler handler) {
        // Allow +/- 3 seconds to prevent flaky tests.
        final long when = SystemClock.elapsedRealtime() + afterSeconds * 1000;
        final long min = when - 3 * 1000;
        final long max = when + 3 * 1000;
        ArgumentCaptor<OnAlarmListener> captor = ArgumentCaptor.forClass(OnAlarmListener.class);
        verifyWithTimeout(inOrder, mAlarm).setExact(
                anyInt(), longThat(x -> x >= min && x <= max),
                contains(tagMatch), captor.capture(), eq(handler));
        return captor.getValue();
    }

    private OnAlarmListener expectAlarmSet(InOrder inOrder, String tagMatch, int afterSeconds) {
        return expectAlarmSet(inOrder, tagMatch, (long) afterSeconds, mIpc.getHandler());
    }

    private boolean packetContainsExpectedField(final byte[] packet, final int offset,
            final byte[] expected) {
        if (packet.length < offset + expected.length) return false;
        for (int i = 0; i < expected.length; ++i) {
            if (packet[offset + i] != expected[i]) return false;
        }
        return true;
    }

    private boolean isDhcpPacket(final byte[] packet) {
        final ByteBuffer buffer = ByteBuffer.wrap(packet);

        // check the packet length
        if (packet.length < DHCP_HEADER_OFFSET) return false;

        // check the source port and dest port in UDP header
        buffer.position(UDP_SRC_PORT_OFFSET);
        final short udpSrcPort = buffer.getShort();
        final short udpDstPort = buffer.getShort();
        if (udpSrcPort != DHCP_CLIENT || udpDstPort != DHCP_SERVER) return false;

        // check DHCP message type
        buffer.position(DHCP_MESSAGE_OP_CODE_OFFSET);
        final byte dhcpOpCode = buffer.get();
        if (dhcpOpCode != DHCP_BOOTREQUEST) return false;

        // check DHCP magic cookie
        buffer.position(DHCP_OPTION_MAGIC_COOKIE_OFFSET);
        final int dhcpMagicCookie = buffer.getInt();
        if (dhcpMagicCookie != DHCP_MAGIC_COOKIE) return false;

        return true;
    }

    private boolean isDhcp6Packet(final byte[] packet) {
        final ByteBuffer buffer = ByteBuffer.wrap(packet);

        // check the packet length
        if (packet.length < DHCP6_HEADER_OFFSET) return false;

        // check Ethernet header
        final EthernetHeader ethHdr = Struct.parse(EthernetHeader.class, buffer);
        if (ethHdr.etherType != ETH_P_IPV6) {
            return false;
        }

        // check IPv6 header
        final Ipv6Header ipv6Hdr = Struct.parse(Ipv6Header.class, buffer);
        final int version = (ipv6Hdr.vtf >> 28) & 0x0F;
        if (version != 6) {
            return false;
        }
        if (ipv6Hdr.nextHeader != IPPROTO_UDP) {
            return false;
        }
        if (!ipv6Hdr.dstIp.equals(ALL_DHCP_RELAY_AGENTS_AND_SERVERS)) {
            return false;
        }
        mClientIpAddress = ipv6Hdr.srcIp;

        // check the source port and dest port in UDP header
        final short udpSrcPort = buffer.getShort();
        final short udpDstPort = buffer.getShort();
        return (udpSrcPort == DHCP6_CLIENT_PORT && udpDstPort == DHCP6_SERVER_PORT);
    }

    private ArpPacket parseArpPacketOrNull(final byte[] packet) {
        try {
            return ArpPacket.parseArpPacket(packet, packet.length);
        } catch (ArpPacket.ParseException e) {
            return null;
        }
    }

    private NeighborAdvertisement parseNeighborAdvertisementOrNull(final byte[] packet) {
        try {
            return NeighborAdvertisement.parse(packet, packet.length);
        } catch (NeighborAdvertisement.ParseException e) {
            return null;
        }
    }

    private NeighborSolicitation parseNeighborSolicitationOrNull(final byte[] packet) {
        try {
            return NeighborSolicitation.parse(packet, packet.length);
        } catch (NeighborSolicitation.ParseException e) {
            return null;
        }
    }

    private static ByteBuffer buildDhcpOfferPacket(final DhcpPacket packet,
            final Inet4Address clientAddress, final Integer leaseTimeSec, final short mtu,
            final String captivePortalUrl, final Integer ipv6OnlyWaitTime) {
        return DhcpPacket.buildOfferPacket(DhcpPacket.ENCAP_L2, packet.getTransactionId(),
                false /* broadcast */, SERVER_ADDR, INADDR_ANY /* relayIp */,
                clientAddress /* yourIp */, packet.getClientMac(), leaseTimeSec,
                NETMASK /* netMask */, BROADCAST_ADDR /* bcAddr */,
                Collections.singletonList(SERVER_ADDR) /* gateways */,
                Collections.singletonList(SERVER_ADDR) /* dnsServers */,
                SERVER_ADDR /* dhcpServerIdentifier */, null /* domainName */, HOSTNAME,
                false /* metered */, mtu, captivePortalUrl, ipv6OnlyWaitTime);
    }

    private static ByteBuffer buildDhcpOfferPacket(final DhcpPacket packet,
            final Inet4Address clientAddress, final Integer leaseTimeSec, final short mtu,
            final String captivePortalUrl) {
        return buildDhcpOfferPacket(packet, clientAddress, leaseTimeSec, mtu, captivePortalUrl,
                null /* ipv6OnlyWaitTime */);
    }

    private static ByteBuffer buildDhcpAckPacket(final DhcpPacket packet,
            final Inet4Address clientAddress, final Integer leaseTimeSec, final short mtu,
            final boolean rapidCommit, final String captivePortalApiUrl,
            final Integer ipv6OnlyWaitTime) {
        return DhcpPacket.buildAckPacket(DhcpPacket.ENCAP_L2, packet.getTransactionId(),
                false /* broadcast */, SERVER_ADDR, INADDR_ANY /* relayIp */,
                clientAddress /* yourIp */, CLIENT_ADDR /* requestIp */, packet.getClientMac(),
                leaseTimeSec, NETMASK /* netMask */, BROADCAST_ADDR /* bcAddr */,
                Collections.singletonList(SERVER_ADDR) /* gateways */,
                Collections.singletonList(SERVER_ADDR) /* dnsServers */,
                SERVER_ADDR /* dhcpServerIdentifier */, null /* domainName */, HOSTNAME,
                false /* metered */, mtu, rapidCommit, captivePortalApiUrl, ipv6OnlyWaitTime);
    }

    private static ByteBuffer buildDhcpAckPacket(final DhcpPacket packet,
            final Inet4Address clientAddress, final Integer leaseTimeSec, final short mtu,
            final boolean rapidCommit, final String captivePortalApiUrl) {
        return buildDhcpAckPacket(packet, clientAddress, leaseTimeSec, mtu, rapidCommit,
                captivePortalApiUrl, null /* ipv6OnlyWaitTime */);
    }

    private static ByteBuffer buildDhcpNakPacket(final DhcpPacket packet, final String message) {
        return DhcpPacket.buildNakPacket(DhcpPacket.ENCAP_L2, packet.getTransactionId(),
            SERVER_ADDR /* serverIp */, INADDR_ANY /* relayIp */, packet.getClientMac(),
            false /* broadcast */, message);
    }

    private static ByteBuffer buildDhcp6Packet(final ByteBuffer payload, final MacAddress clientMac,
            final Inet6Address clientIp) throws Exception {
        final ByteBuffer buffer = PacketBuilder.allocate(true /* hasEther */, IPPROTO_IPV6,
                IPPROTO_UDP, payload.limit());
        final PacketBuilder pb = new PacketBuilder(buffer);

        pb.writeL2Header(ROUTER_MAC /* srcMac */, clientMac /* dstMac */, (short) ETH_P_IPV6);
        pb.writeIpv6Header(0x60000000 /* version=6, traffic class=0, flow label=0 */,
                (byte) IPPROTO_UDP, (short) 64 /* hop limit */, ROUTER_LINK_LOCAL /* srcIp */,
                clientIp /* dstIp */);
        pb.writeUdpHeader((short) DHCP6_SERVER_PORT /*src port */,
                (short) DHCP6_CLIENT_PORT /* dst port */);
        buffer.put(payload);
        return pb.finalizePacket();
    }

    private static ByteBuffer buildDhcp6Advertise(final Dhcp6Packet solicit, final byte[] iapd,
            final byte[] clientMac, final Inet6Address clientIp) throws Exception {
        final ByteBuffer advertise = Dhcp6Packet.buildAdvertisePacket(solicit.getTransactionId(),
                iapd, solicit.getClientDuid(), ROUTER_DUID);
        return buildDhcp6Packet(advertise, MacAddress.fromBytes(clientMac), clientIp);
    }

    private static ByteBuffer buildDhcp6Reply(final Dhcp6Packet request, final byte[] iapd,
            final byte[] clientMac, final Inet6Address clientIp, boolean rapidCommit)
            throws Exception {
        final ByteBuffer reply = Dhcp6Packet.buildReplyPacket(request.getTransactionId(),
                iapd, request.getClientDuid(), ROUTER_DUID, rapidCommit);
        return buildDhcp6Packet(reply, MacAddress.fromBytes(clientMac), clientIp);
    }

    private void sendArpReply(final byte[] dstMac, final byte[] srcMac, final Inet4Address targetIp,
            final Inet4Address senderIp) throws IOException {
        final ByteBuffer packet = ArpPacket.buildArpPacket(dstMac, srcMac, targetIp.getAddress(),
                dstMac /* target HW address */, senderIp.getAddress(), (short) ARP_REPLY);
        mPacketReader.sendResponse(packet);
    }

    private void sendArpProbe() throws IOException {
        final ByteBuffer packet = ArpPacket.buildArpPacket(DhcpPacket.ETHER_BROADCAST /* dst */,
                ROUTER_MAC_BYTES /* srcMac */, CLIENT_ADDR.getAddress() /* target IP */,
                new byte[ETHER_ADDR_LEN] /* target HW address */,
                INADDR_ANY.getAddress() /* sender IP */, (short) ARP_REQUEST);
        mPacketReader.sendResponse(packet);
    }

    private void startIpClientProvisioning(final ProvisioningConfiguration cfg) throws Exception {
        mIIpClient.startProvisioning(cfg.toStableParcelable());
    }

    private void startIpClientProvisioning(final boolean isDhcpLeaseCacheEnabled,
            final boolean shouldReplyRapidCommitAck, final boolean isPreconnectionEnabled,
            final boolean isDhcpIpConflictDetectEnabled, final boolean isIPv6OnlyPreferredEnabled,
            final String displayName, final ScanResultInfo scanResultInfo,
            final Layer2Information layer2Info) throws Exception {
        ProvisioningConfiguration.Builder prov = new ProvisioningConfiguration.Builder()
                .withoutIpReachabilityMonitor()
                .withLayer2Information(layer2Info == null
                        ? new Layer2Information(TEST_L2KEY, TEST_CLUSTER,
                              MacAddress.fromString(TEST_DEFAULT_BSSID))
                        : layer2Info)
                .withoutIPv6();
        if (isPreconnectionEnabled) prov.withPreconnection();
        if (displayName != null) prov.withDisplayName(displayName);
        if (scanResultInfo != null) prov.withScanResultInfo(scanResultInfo);

        setDhcpFeatures(isDhcpLeaseCacheEnabled, shouldReplyRapidCommitAck,
                isDhcpIpConflictDetectEnabled, isIPv6OnlyPreferredEnabled);

        startIpClientProvisioning(prov.build());
        if (!isPreconnectionEnabled) {
            verify(mCb, timeout(TEST_TIMEOUT_MS)).setFallbackMulticastFilter(true);
        }
        verify(mCb, never()).onProvisioningFailure(any());
    }

    private void startIpClientProvisioning(final boolean isDhcpLeaseCacheEnabled,
            final boolean isDhcpRapidCommitEnabled, final boolean isPreconnectionEnabled,
            final boolean isDhcpIpConflictDetectEnabled, final boolean isIPv6OnlyPreferredEnabled)
            throws Exception {
        startIpClientProvisioning(isDhcpLeaseCacheEnabled, isDhcpRapidCommitEnabled,
                isPreconnectionEnabled, isDhcpIpConflictDetectEnabled, isIPv6OnlyPreferredEnabled,
                null /* displayName */, null /* ScanResultInfo */, null /* layer2Info */);
    }

    private void assertIpMemoryStoreNetworkAttributes(final Integer leaseTimeSec,
            final long startTime, final int mtu) {
        final NetworkAttributes na = getStoredNetworkAttributes(TEST_L2KEY, TEST_TIMEOUT_MS);
        assertNotNull(na);
        assertEquals(CLIENT_ADDR, na.assignedV4Address);
        if (leaseTimeSec == null || leaseTimeSec.intValue() == DhcpPacket.INFINITE_LEASE) {
            assertEquals(Long.MAX_VALUE, na.assignedV4AddressExpiry.longValue());
        } else {
            // check the lease expiry's scope
            final long upperBound = startTime + 7_200_000; // start timestamp + 2h
            final long lowerBound = startTime + 3_600_000; // start timestamp + 1h
            final long expiry = na.assignedV4AddressExpiry;
            assertTrue(upperBound > expiry);
            assertTrue(lowerBound < expiry);
        }
        assertEquals(Collections.singletonList(SERVER_ADDR), na.dnsAddresses);
        assertEquals(new Integer(mtu), na.mtu);
    }

    private void assertIpMemoryNeverStoreNetworkAttributes() {
        assertIpMemoryNeverStoreNetworkAttributes(TEST_L2KEY, TEST_TIMEOUT_MS);
    }

    private void assertHostname(final boolean isHostnameConfigurationEnabled,
            final String hostname, final String hostnameAfterTransliteration,
            final List<DhcpPacket> packetList) throws Exception {
        for (DhcpPacket packet : packetList) {
            if (!isHostnameConfigurationEnabled || hostname == null) {
                assertNoHostname(packet.getHostname());
            } else {
                assertEquals(packet.getHostname(), hostnameAfterTransliteration);
            }
        }
    }

    private void assertNoHostname(String hostname) {
        if (ShimUtils.isAtLeastR()) {
            assertNull(hostname);
        } else {
            // Until Q, if no hostname is set, the device falls back to the hostname set via
            // system property, to avoid breaking Q devices already launched with that setup.
            assertEquals(SystemProperties.get("net.hostname"), hostname);
        }
    }

    // Helper method to complete DHCP 2-way or 4-way handshake
    private List<DhcpPacket> performDhcpHandshake(final boolean isSuccessLease,
            final Integer leaseTimeSec, final boolean isDhcpLeaseCacheEnabled,
            final boolean shouldReplyRapidCommitAck, final int mtu,
            final boolean isDhcpIpConflictDetectEnabled,
            final boolean isIPv6OnlyPreferredEnabled,
            final String captivePortalApiUrl, final String displayName,
            final ScanResultInfo scanResultInfo, final Layer2Information layer2Info)
            throws Exception {
        startIpClientProvisioning(isDhcpLeaseCacheEnabled, shouldReplyRapidCommitAck,
                false /* isPreconnectionEnabled */, isDhcpIpConflictDetectEnabled,
                isIPv6OnlyPreferredEnabled, displayName, scanResultInfo, layer2Info);
        return handleDhcpPackets(isSuccessLease, leaseTimeSec, shouldReplyRapidCommitAck, mtu,
                captivePortalApiUrl);
    }

    private List<DhcpPacket> handleDhcpPackets(final boolean isSuccessLease,
            final Integer leaseTimeSec, final boolean shouldReplyRapidCommitAck, final int mtu,
            final String captivePortalApiUrl) throws Exception {
        final List<DhcpPacket> packetList = new ArrayList<>();
        DhcpPacket packet;
        while ((packet = getNextDhcpPacket()) != null) {
            packetList.add(packet);
            if (packet instanceof DhcpDiscoverPacket) {
                if (shouldReplyRapidCommitAck) {
                    mPacketReader.sendResponse(buildDhcpAckPacket(packet, CLIENT_ADDR, leaseTimeSec,
                              (short) mtu, true /* rapidCommit */, captivePortalApiUrl));
                } else {
                    mPacketReader.sendResponse(buildDhcpOfferPacket(packet, CLIENT_ADDR,
                            leaseTimeSec, (short) mtu, captivePortalApiUrl));
                }
            } else if (packet instanceof DhcpRequestPacket) {
                final ByteBuffer byteBuffer = isSuccessLease
                        ? buildDhcpAckPacket(packet, CLIENT_ADDR, leaseTimeSec, (short) mtu,
                                false /* rapidCommit */, captivePortalApiUrl)
                        : buildDhcpNakPacket(packet, "duplicated request IP address");
                mPacketReader.sendResponse(byteBuffer);
            } else {
                fail("invalid DHCP packet");
            }

            // wait for reply to DHCPOFFER packet if disabling rapid commit option
            if (shouldReplyRapidCommitAck || !(packet instanceof DhcpDiscoverPacket)) {
                return packetList;
            }
        }
        fail("No DHCPREQUEST received on interface");
        return packetList;
    }

    private List<DhcpPacket> performDhcpHandshake(final boolean isSuccessLease,
            final Integer leaseTimeSec, final boolean isDhcpLeaseCacheEnabled,
            final boolean isDhcpRapidCommitEnabled, final int mtu,
            final boolean isDhcpIpConflictDetectEnabled) throws Exception {
        return performDhcpHandshake(isSuccessLease, leaseTimeSec, isDhcpLeaseCacheEnabled,
                isDhcpRapidCommitEnabled, mtu, isDhcpIpConflictDetectEnabled,
                false /* isIPv6OnlyPreferredEnabled */,
                null /* captivePortalApiUrl */, null /* displayName */, null /* scanResultInfo */,
                null /* layer2Info */);
    }

    private List<DhcpPacket> performDhcpHandshake() throws Exception {
        return performDhcpHandshake(true /* isSuccessLease */, TEST_LEASE_DURATION_S,
                false /* isDhcpLeaseCacheEnabled */, false /* shouldReplyRapidCommitAck */,
                TEST_DEFAULT_MTU, false /* isDhcpIpConflictDetectEnabled */);
    }

    private DhcpPacket getNextDhcpPacket(final long timeout) throws Exception {
        byte[] packet;
        while ((packet = mDhcpPacketReadHead.getValue()
                .poll(timeout, this::isDhcpPacket)) != null) {
            final DhcpPacket dhcpPacket = DhcpPacket.decodeFullPacket(packet, packet.length,
                    ENCAP_L2);
            if (dhcpPacket != null) return dhcpPacket;
        }
        return null;
    }

    private DhcpPacket getNextDhcpPacket() throws Exception {
        final DhcpPacket packet = getNextDhcpPacket(PACKET_TIMEOUT_MS);
        assertNotNull("No expected DHCP packet received on interface within timeout", packet);
        return packet;
    }

    private Dhcp6Packet getNextDhcp6Packet(final long timeout) throws Exception {
        byte[] packet;
        while ((packet = mDhcp6PacketReadHead.getValue()
                .poll(timeout, this::isDhcp6Packet)) != null) {
            // Strip the Ethernet/IPv6/UDP headers, only keep DHCPv6 message payload for decode.
            final byte[] payload =
                    Arrays.copyOfRange(packet, DHCP6_HEADER_OFFSET, packet.length);
            final Dhcp6Packet dhcp6Packet = Dhcp6Packet.decode(payload, payload.length);
            if (dhcp6Packet != null) return dhcp6Packet;
        }
        return null;
    }

    private Dhcp6Packet getNextDhcp6Packet() throws Exception {
        final Dhcp6Packet packet = getNextDhcp6Packet(PACKET_TIMEOUT_MS);
        assertNotNull("No expected DHCPv6 packet received on interface within timeout", packet);
        return packet;
    }

    private DhcpPacket getReplyFromDhcpLease(final NetworkAttributes na, boolean timeout)
            throws Exception {
        doAnswer(invocation -> {
            if (timeout) return null;
            ((OnNetworkAttributesRetrievedListener) invocation.getArgument(1))
                    .onNetworkAttributesRetrieved(new Status(SUCCESS), TEST_L2KEY, na);
            return null;
        }).when(mIpMemoryStore).retrieveNetworkAttributes(eq(TEST_L2KEY), any());
        startIpClientProvisioning(true /* isDhcpLeaseCacheEnabled */,
                false /* shouldReplyRapidCommitAck */, false /* isPreconnectionEnabled */,
                false /* isDhcpIpConflictDetectEnabled */, false /* isIPv6OnlyPreferredEnabled */);
        return getNextDhcpPacket();
    }

    private void removeTestInterface(final FileDescriptor fd) {
        try {
            Os.close(fd);
        } catch (ErrnoException e) {
            fail("Fail to close file descriptor: " + e);
        }
    }

    private void verifyAfterIpClientShutdown() throws RemoteException {
        final LinkProperties emptyLp = new LinkProperties();
        emptyLp.setInterfaceName(mIfaceName);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onLinkPropertiesChange(emptyLp);
    }

    // Verify IPv4-only provisioning success. No need to verify IPv4 provisioning when below cases
    // happen:
    // 1. if there's a failure lease, onProvisioningSuccess() won't be called;
    // 2. if duplicated IPv4 address detection is enabled, verify TIMEOUT will affect ARP packets
    //    capture running in other test cases.
    // 3. if IPv6 is enabled, e.g. withoutIPv6() isn't called when starting provisioning.
    private LinkProperties verifyIPv4OnlyProvisioningSuccess(
            final Collection<InetAddress> addresses) throws Exception {
        final ArgumentCaptor<LinkProperties> captor = ArgumentCaptor.forClass(LinkProperties.class);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningSuccess(captor.capture());
        final LinkProperties lp = captor.getValue();
        assertNotNull(lp);
        assertNotEquals(0, lp.getDnsServers().size());
        assertEquals(addresses.size(), lp.getAddresses().size());
        assertTrue(lp.getAddresses().containsAll(addresses));
        assertTrue(hasRouteTo(lp, IPV4_TEST_SUBNET_PREFIX)); // IPv4 directly-connected route
        assertTrue(hasRouteTo(lp, IPV4_ANY_ADDRESS_PREFIX)); // IPv4 default route
        return lp;
    }

    private void doRestoreInitialMtuTest(final boolean shouldChangeMtu,
            final boolean shouldRemoveTestInterface) 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 /* shouldReplyRapidCommitAck */,
                mtu, false /* isDhcpIpConflictDetectEnabled */);
        verifyIPv4OnlyProvisioningSuccess(Collections.singletonList(CLIENT_ADDR));
        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);
        }

        // Sometimes, IpClient receives an update with an empty LinkProperties during startup,
        // when the link-local address is deleted after interface bringup. Reset expectations
        // here to ensure that verifyAfterIpClientShutdown does not fail because it sees two
        // empty LinkProperties changes instead of one.
        reset(mCb);

        if (shouldRemoveTestInterface) removeTestInterface(mTapFd);
        try {
            mIpc.shutdown();
            awaitIpClientShutdown();
            if (shouldRemoveTestInterface) {
                verify(mNetd, never()).interfaceSetMtu(mIfaceName, TEST_DEFAULT_MTU);
            } else {
                // Verify that MTU indeed has been restored or not.
                verify(mNetd, times(shouldChangeMtu ? 1 : 0))
                        .interfaceSetMtu(mIfaceName, TEST_DEFAULT_MTU);
            }
            verifyAfterIpClientShutdown();
        } catch (Exception e) {
            fail("Exception should not have been thrown after shutdown: " + e);
        }
    }

    private DhcpPacket assertDiscoverPacketOnPreconnectionStart() throws Exception {
        final ArgumentCaptor<List<Layer2PacketParcelable>> l2PacketList =
                ArgumentCaptor.forClass(List.class);

        verify(mCb, timeout(TEST_TIMEOUT_MS)).onPreconnectionStart(l2PacketList.capture());
        final byte[] payload = l2PacketList.getValue().get(0).payload;
        DhcpPacket packet = DhcpPacket.decodeFullPacket(payload, payload.length, ENCAP_L2);
        assertTrue(packet instanceof DhcpDiscoverPacket);
        assertArrayEquals(INADDR_BROADCAST.getAddress(),
                Arrays.copyOfRange(payload, IPV4_DST_ADDR_OFFSET, IPV4_DST_ADDR_OFFSET + 4));
        return packet;
    }

    private void doIpClientProvisioningWithPreconnectionTest(
            final boolean shouldReplyRapidCommitAck, final boolean shouldAbortPreconnection,
            final boolean shouldFirePreconnectionTimeout,
            final boolean timeoutBeforePreconnectionComplete) throws Exception {
        final long currentTime = System.currentTimeMillis();
        final ArgumentCaptor<InterfaceConfigurationParcel> ifConfig =
                ArgumentCaptor.forClass(InterfaceConfigurationParcel.class);

        startIpClientProvisioning(true /* isDhcpLeaseCacheEnabled */,
                shouldReplyRapidCommitAck, true /* isDhcpPreConnectionEnabled */,
                false /* isDhcpIpConflictDetectEnabled */, false /* isIPv6OnlyPreferredEnabled */);
        DhcpPacket packet = assertDiscoverPacketOnPreconnectionStart();
        final int preconnDiscoverTransId = packet.getTransactionId();

        if (shouldAbortPreconnection) {
            if (shouldFirePreconnectionTimeout && timeoutBeforePreconnectionComplete) {
                mDependencies.mDhcpClient.sendMessage(DhcpClient.CMD_TIMEOUT);
            }

            mIpc.notifyPreconnectionComplete(false /* abort */);
            HandlerUtils.waitForIdle(mIpc.getHandler(), TEST_TIMEOUT_MS);

            if (shouldFirePreconnectionTimeout && !timeoutBeforePreconnectionComplete) {
                mDependencies.mDhcpClient.sendMessage(DhcpClient.CMD_TIMEOUT);
            }

            // Either way should get DhcpClient go back to INIT state, and broadcast
            // DISCOVER with new transaction ID.
            packet = getNextDhcpPacket();
            assertTrue(packet instanceof DhcpDiscoverPacket);
            assertTrue(packet.getTransactionId() != preconnDiscoverTransId);
        } else if (shouldFirePreconnectionTimeout && timeoutBeforePreconnectionComplete) {
            // If timeout fires before success preconnection, DhcpClient will go back to INIT state,
            // and broadcast DISCOVER with new transaction ID.
            mDependencies.mDhcpClient.sendMessage(DhcpClient.CMD_TIMEOUT);
            packet = getNextDhcpPacket();
            assertTrue(packet instanceof DhcpDiscoverPacket);
            assertTrue(packet.getTransactionId() != preconnDiscoverTransId);
            // any old response would be ignored due to mismatched transaction ID.
        }

        final short mtu = (short) TEST_DEFAULT_MTU;
        if (!shouldReplyRapidCommitAck) {
            mPacketReader.sendResponse(buildDhcpOfferPacket(packet, CLIENT_ADDR,
                    TEST_LEASE_DURATION_S, mtu, null /* captivePortalUrl */));
            packet = getNextDhcpPacket();
            assertTrue(packet instanceof DhcpRequestPacket);
        }
        mPacketReader.sendResponse(buildDhcpAckPacket(packet, CLIENT_ADDR, TEST_LEASE_DURATION_S,
                mtu, shouldReplyRapidCommitAck, null /* captivePortalUrl */));

        if (!shouldAbortPreconnection) {
            mIpc.notifyPreconnectionComplete(true /* success */);
            HandlerUtils.waitForIdle(mDependencies.mDhcpClient.getHandler(), TEST_TIMEOUT_MS);

            // If timeout fires after successful preconnection, right now DhcpClient will have
            // already entered BOUND state, the delayed CMD_TIMEOUT command would be ignored. So
            // this case should be very rare, because the timeout alarm is cancelled when state
            // machine exits from Preconnecting state.
            if (shouldFirePreconnectionTimeout && !timeoutBeforePreconnectionComplete) {
                mDependencies.mDhcpClient.sendMessage(DhcpClient.CMD_TIMEOUT);
            }
        }
        verify(mCb, timeout(TEST_TIMEOUT_MS)).setFallbackMulticastFilter(true);

        final LinkAddress ipAddress = new LinkAddress(CLIENT_ADDR, PREFIX_LENGTH);
        verify(mNetd, timeout(TEST_TIMEOUT_MS).times(1)).interfaceSetCfg(ifConfig.capture());
        assertEquals(ifConfig.getValue().ifName, mIfaceName);
        assertEquals(ifConfig.getValue().ipv4Addr, ipAddress.getAddress().getHostAddress());
        assertEquals(ifConfig.getValue().prefixLength, PREFIX_LENGTH);
        assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, TEST_DEFAULT_MTU);
    }

    private ArpPacket getNextArpPacket(final long timeout) throws Exception {
        byte[] packet;
        while ((packet = mArpPacketReadHead.getValue().poll(timeout, p -> true)) != null) {
            final ArpPacket arpPacket = parseArpPacketOrNull(packet);
            if (arpPacket != null) return arpPacket;
        }
        return null;
    }

    private ArpPacket getNextArpPacket() throws Exception {
        final ArpPacket packet = getNextArpPacket(PACKET_TIMEOUT_MS);
        assertNotNull("No expected ARP packet received on interface within timeout", packet);
        return packet;
    }

    private void assertArpPacket(final ArpPacket packet) {
        assertEquals(packet.opCode, ARP_REQUEST);
        assertEquals(packet.targetIp, CLIENT_ADDR);
        assertTrue(Arrays.equals(packet.senderHwAddress.toByteArray(), mClientMac));
    }

    private void assertArpProbe(final ArpPacket packet) {
        assertArpPacket(packet);
        assertEquals(packet.senderIp, INADDR_ANY);
    }

    private void assertArpAnnounce(final ArpPacket packet) {
        assertArpPacket(packet);
        assertEquals(packet.senderIp, CLIENT_ADDR);
    }

    private void assertArpRequest(final ArpPacket packet, final Inet4Address targetIp) {
        assertEquals(packet.opCode, ARP_REQUEST);
        assertEquals(packet.senderIp, CLIENT_ADDR);
        assertEquals(packet.targetIp, targetIp);
        assertTrue(Arrays.equals(packet.targetHwAddress.toByteArray(),
                MacAddress.fromString("00:00:00:00:00:00").toByteArray()));
        assertTrue(Arrays.equals(packet.senderHwAddress.toByteArray(), mClientMac));
    }

    private void assertGratuitousARP(final ArpPacket packet) {
        assertEquals(packet.opCode, ARP_REPLY);
        assertEquals(packet.senderIp, CLIENT_ADDR);
        assertEquals(packet.targetIp, CLIENT_ADDR);
        assertTrue(Arrays.equals(packet.senderHwAddress.toByteArray(), mClientMac));
        assertTrue(Arrays.equals(packet.targetHwAddress.toByteArray(), ETHER_BROADCAST));
    }

    private void doIpAddressConflictDetectionTest(final boolean causeIpAddressConflict,
            final boolean shouldReplyRapidCommitAck, final boolean isDhcpIpConflictDetectEnabled,
            final boolean shouldResponseArpReply) throws Exception {
        final long currentTime = System.currentTimeMillis();

        performDhcpHandshake(true /* isSuccessLease */, TEST_LEASE_DURATION_S,
                true /* isDhcpLeaseCacheEnabled */, shouldReplyRapidCommitAck,
                TEST_DEFAULT_MTU, isDhcpIpConflictDetectEnabled);

        // If we receive an ARP packet here, it's guaranteed to be from IP conflict detection,
        // because at this time the test interface does not have an IP address and therefore
        // won't send ARP for anything.
        if (causeIpAddressConflict) {
            final ArpPacket arpProbe = getNextArpPacket();
            assertArpProbe(arpProbe);

            if (shouldResponseArpReply) {
                sendArpReply(mClientMac /* dstMac */, ROUTER_MAC_BYTES /* srcMac */,
                        INADDR_ANY /* target IP */, CLIENT_ADDR /* sender IP */);
            } else {
                sendArpProbe();
            }
            final DhcpPacket packet = getNextDhcpPacket();
            assertTrue(packet instanceof DhcpDeclinePacket);
            assertEquals(packet.mServerIdentifier, SERVER_ADDR);
            assertEquals(packet.mRequestedIp, CLIENT_ADDR);

            verify(mCb, never()).onProvisioningFailure(any());
            assertIpMemoryNeverStoreNetworkAttributes();
        } else if (isDhcpIpConflictDetectEnabled) {
            int arpPacketCount = 0;
            final List<ArpPacket> packetList = new ArrayList<ArpPacket>();
            // Total sent ARP packets should be 5 (3 ARP Probes + 2 ARP Announcements)
            ArpPacket packet;
            while ((packet = getNextArpPacket(TEST_TIMEOUT_MS)) != null) {
                packetList.add(packet);
            }
            assertEquals(5, packetList.size());
            assertArpProbe(packetList.get(0));
            assertArpAnnounce(packetList.get(3));
        } else {
            verifyIPv4OnlyProvisioningSuccess(Collections.singletonList(CLIENT_ADDR));
            assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime,
                    TEST_DEFAULT_MTU);
        }
    }

    @Test @SignatureRequiredTest(reason = "InterfaceParams.getByName requires CAP_NET_ADMIN")
    public void testInterfaceParams() throws Exception {
        InterfaceParams params = InterfaceParams.getByName(mIfaceName);
        assertNotNull(params);
        assertEquals(mIfaceName, params.name);
        assertTrue(params.index > 0);
        assertNotNull(params.macAddr);
        assertTrue(params.hasMacAddress);

        //  Check interface "lo".
        params = InterfaceParams.getByName("lo");
        assertNotNull(params);
        assertEquals("lo", params.name);
        assertTrue(params.index > 0);
        assertNotNull(params.macAddr);
        assertFalse(params.hasMacAddress);
    }

    @Test
    public void testDhcpInit() throws Exception {
        startIpClientProvisioning(false /* isDhcpLeaseCacheEnabled */,
                false /* shouldReplyRapidCommitAck */, false /* isPreconnectionEnabled */,
                false /* isDhcpIpConflictDetectEnabled */, false /* isIPv6OnlyPreferredEnabled */);
        final DhcpPacket packet = getNextDhcpPacket();
        assertTrue(packet instanceof DhcpDiscoverPacket);
    }

    @Test
    public void testHandleSuccessDhcpLease() throws Exception {
        final long currentTime = System.currentTimeMillis();
        performDhcpHandshake(true /* isSuccessLease */, TEST_LEASE_DURATION_S,
                true /* isDhcpLeaseCacheEnabled */, false /* shouldReplyRapidCommitAck */,
                TEST_DEFAULT_MTU, false /* isDhcpIpConflictDetectEnabled */);
        verifyIPv4OnlyProvisioningSuccess(Collections.singletonList(CLIENT_ADDR));
        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 /* shouldReplyRapidCommitAck */,
                TEST_DEFAULT_MTU, false /* isDhcpIpConflictDetectEnabled */);

        verify(mCb, never()).onProvisioningSuccess(any());
        assertIpMemoryNeverStoreNetworkAttributes();
    }

    @Test
    public void testHandleInfiniteLease() throws Exception {
        final long currentTime = System.currentTimeMillis();
        performDhcpHandshake(true /* isSuccessLease */, INFINITE_LEASE,
                true /* isDhcpLeaseCacheEnabled */, false /* shouldReplyRapidCommitAck */,
                TEST_DEFAULT_MTU, false /* isDhcpIpConflictDetectEnabled */);
        verifyIPv4OnlyProvisioningSuccess(Collections.singletonList(CLIENT_ADDR));
        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 /* shouldReplyRapidCommitAck */,
                TEST_DEFAULT_MTU, false /* isDhcpIpConflictDetectEnabled */);
        verifyIPv4OnlyProvisioningSuccess(Collections.singletonList(CLIENT_ADDR));
        assertIpMemoryStoreNetworkAttributes(null, currentTime, TEST_DEFAULT_MTU);
    }

    @Test @IgnoreAfter(Build.VERSION_CODES.Q) // INIT-REBOOT is enabled on R.
    public void testHandleDisableInitRebootState() throws Exception {
        performDhcpHandshake(true /* isSuccessLease */, TEST_LEASE_DURATION_S,
                false /* isDhcpLeaseCacheEnabled */, false /* shouldReplyRapidCommitAck */,
                TEST_DEFAULT_MTU, false /* isDhcpIpConflictDetectEnabled */);
        verifyIPv4OnlyProvisioningSuccess(Collections.singletonList(CLIENT_ADDR));
        assertIpMemoryNeverStoreNetworkAttributes();
    }

    @Test
    public void testHandleRapidCommitOption() throws Exception {
        final long currentTime = System.currentTimeMillis();
        performDhcpHandshake(true /* isSuccessLease */, TEST_LEASE_DURATION_S,
                true /* isDhcpLeaseCacheEnabled */, true /* shouldReplyRapidCommitAck */,
                TEST_DEFAULT_MTU, false /* isDhcpIpConflictDetectEnabled */);
        verifyIPv4OnlyProvisioningSuccess(Collections.singletonList(CLIENT_ADDR));
        assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, TEST_DEFAULT_MTU);
    }

    @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
    public void testRollbackFromRapidCommitOption() throws Exception {
        startIpClientProvisioning(false /* isDhcpLeaseCacheEnabled */,
                true /* isDhcpRapidCommitEnabled */, false /* isPreConnectionEnabled */,
                false /* isDhcpIpConflictDetectEnabled */, false /* isIPv6OnlyPreferredEnabled */);

        final List<DhcpPacket> discoverList = new ArrayList<DhcpPacket>();
        DhcpPacket packet;
        do {
            packet = getNextDhcpPacket();
            assertTrue(packet instanceof DhcpDiscoverPacket);
            discoverList.add(packet);
        } while (discoverList.size() < 4);

        // Check the only first 3 DHCPDISCOVERs take rapid commit option.
        assertTrue(discoverList.get(0).mRapidCommit);
        assertTrue(discoverList.get(1).mRapidCommit);
        assertTrue(discoverList.get(2).mRapidCommit);
        assertFalse(discoverList.get(3).mRapidCommit);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpClientStartWithCachedInfiniteLease() throws Exception {
        final DhcpPacket packet = getReplyFromDhcpLease(
                new NetworkAttributes.Builder()
                    .setAssignedV4Address(CLIENT_ADDR)
                    .setAssignedV4AddressExpiry(Long.MAX_VALUE) // lease is always valid
                    .setMtu(new Integer(TEST_DEFAULT_MTU))
                    .setCluster(TEST_CLUSTER)
                    .setDnsAddresses(Collections.singletonList(SERVER_ADDR))
                    .build(), false /* timeout */);
        assertTrue(packet instanceof DhcpRequestPacket);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpClientStartWithCachedExpiredLease() throws Exception {
        final DhcpPacket packet = getReplyFromDhcpLease(
                 new NetworkAttributes.Builder()
                    .setAssignedV4Address(CLIENT_ADDR)
                    .setAssignedV4AddressExpiry(EXPIRED_LEASE)
                    .setMtu(new Integer(TEST_DEFAULT_MTU))
                    .setCluster(TEST_CLUSTER)
                    .setDnsAddresses(Collections.singletonList(SERVER_ADDR))
                    .build(), false /* timeout */);
        assertTrue(packet instanceof DhcpDiscoverPacket);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpClientStartWithNullRetrieveNetworkAttributes() throws Exception {
        final DhcpPacket packet = getReplyFromDhcpLease(null /* na */, false /* timeout */);
        assertTrue(packet instanceof DhcpDiscoverPacket);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpClientStartWithTimeoutRetrieveNetworkAttributes() throws Exception {
        final DhcpPacket packet = getReplyFromDhcpLease(
                new NetworkAttributes.Builder()
                    .setAssignedV4Address(CLIENT_ADDR)
                    .setAssignedV4AddressExpiry(System.currentTimeMillis() + 3_600_000)
                    .setMtu(new Integer(TEST_DEFAULT_MTU))
                    .setCluster(TEST_CLUSTER)
                    .setDnsAddresses(Collections.singletonList(SERVER_ADDR))
                    .build(), true /* timeout */);
        assertTrue(packet instanceof DhcpDiscoverPacket);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpClientStartWithCachedLeaseWithoutIPAddress() throws Exception {
        final DhcpPacket packet = getReplyFromDhcpLease(
                new NetworkAttributes.Builder()
                    .setMtu(new Integer(TEST_DEFAULT_MTU))
                    .setCluster(TEST_CLUSTER)
                    .setDnsAddresses(Collections.singletonList(SERVER_ADDR))
                    .build(), false /* timeout */);
        assertTrue(packet instanceof DhcpDiscoverPacket);
    }

    @Test
    public void testDhcpClientRapidCommitEnabled() throws Exception {
        startIpClientProvisioning(false /* isDhcpLeaseCacheEnabled */,
                true /* shouldReplyRapidCommitAck */, false /* isPreconnectionEnabled */,
                false /* isDhcpIpConflictDetectEnabled */, false /* isIPv6OnlyPreferredEnabled */);
        final DhcpPacket packet = getNextDhcpPacket();
        assertTrue(packet instanceof DhcpDiscoverPacket);
    }

    @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
    public void testDhcpServerInLinkProperties() throws Exception {
        assumeTrue(ConstantsShim.VERSION > Build.VERSION_CODES.Q);

        performDhcpHandshake();
        ArgumentCaptor<LinkProperties> captor = ArgumentCaptor.forClass(LinkProperties.class);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningSuccess(captor.capture());
        assertEquals(SERVER_ADDR, captor.getValue().getDhcpServerAddress());
    }

    private void createTestNetworkAgentAndRegister(final LinkProperties lp) throws Exception {
        final Context context = InstrumentationRegistry.getInstrumentation().getContext();
        final ConnectivityManager cm = context.getSystemService(ConnectivityManager.class);
        final NetworkSpecifier testNetworkSpecifier =
                CompatUtil.makeTestNetworkSpecifier(mIfaceName);
        final TestableNetworkCallback cb = new TestableNetworkCallback();

        // Requesting a network make sure the NetworkAgent is alive during the whole life cycle of
        // requested network.
        cm.requestNetwork(new NetworkRequest.Builder()
                .removeCapability(NET_CAPABILITY_TRUSTED)
                .removeCapability(NET_CAPABILITY_INTERNET)
                .addTransportType(TRANSPORT_TEST)
                .setNetworkSpecifier(testNetworkSpecifier)
                .build(), cb);
        mNetworkAgent = new TestableNetworkAgent(context, mNetworkAgentThread.getLooper(),
                new NetworkCapabilities.Builder()
                        .removeCapability(NET_CAPABILITY_TRUSTED)
                        .removeCapability(NET_CAPABILITY_INTERNET)
                        .addCapability(NET_CAPABILITY_NOT_SUSPENDED)
                        .addCapability(NET_CAPABILITY_NOT_ROAMING)
                        .addCapability(NET_CAPABILITY_NOT_VPN)
                        .addCapability(NET_CAPABILITY_NOT_RESTRICTED)
                        .addTransportType(TRANSPORT_TEST)
                        .setNetworkSpecifier(testNetworkSpecifier)
                        .build(),
                lp,
                new NetworkAgentConfig.Builder().build());
        mNetworkAgent.register();
        mNetworkAgent.markConnected();
        cb.expectAvailableThenValidatedCallbacks(mNetworkAgent.getNetwork(), TEST_TIMEOUT_MS);
    }

    private void assertReceivedDhcpRequestPacketCount() throws Exception {
        final List<DhcpPacket> packetList = new ArrayList<>();
        DhcpPacket packet;
        while ((packet = getNextDhcpPacket(PACKET_TIMEOUT_MS)) != null) {
            assertDhcpRequestForReacquire(packet);
            packetList.add(packet);
        }
        assertEquals(1, packetList.size());
    }

    private LinkProperties prepareDhcpReacquireTest() throws Exception {
        mNetworkAgentThread =
                new HandlerThread(IpClientIntegrationTestCommon.class.getSimpleName());
        mNetworkAgentThread.start();

        final long currentTime = System.currentTimeMillis();
        setFeatureEnabled(NetworkStackUtils.DHCP_SLOW_RETRANSMISSION_VERSION, true);
        performDhcpHandshake(true /* isSuccessLease */,
                TEST_LEASE_DURATION_S, true /* isDhcpLeaseCacheEnabled */,
                false /* isDhcpRapidCommitEnabled */, TEST_DEFAULT_MTU,
                false /* isDhcpIpConflictDetectEnabled */);
        final LinkProperties lp =
                verifyIPv4OnlyProvisioningSuccess(Collections.singletonList(CLIENT_ADDR));
        assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, TEST_DEFAULT_MTU);
        return lp;
    }

    private OnAlarmListener runDhcpRenewTest(final Handler handler, final LinkProperties lp,
            final InOrder inOrder) throws Exception {
        // Create a NetworkAgent and register it to ConnectivityService with IPv4 LinkProperties,
        // then ConnectivityService will call netd API to configure the IPv4 route on the kernel,
        // otherwise, unicast DHCPREQUEST cannot be sent out due to no route to host(EHOSTUNREACH).
        runAsShell(MANAGE_TEST_NETWORKS, () -> createTestNetworkAgentAndRegister(lp));

        // DHCP client is in BOUND state right now, simulate the renewal via triggering renew alarm
        // which should happen at T1. E.g. lease duration is 3600s, T1 = lease_duration * 0.5(1800s)
        // T2 = lease_duration * 0.875(3150s).
        final OnAlarmListener renewAlarm = expectAlarmSet(inOrder, "RENEW", 1800, handler);
        final OnAlarmListener rebindAlarm = expectAlarmSet(inOrder, "REBIND", 3150, handler);

        // Trigger renew alarm and force DHCP client enter RenewingState. Device needs to start
        // the ARP resolution for the fake DHCP server IPv4 address before sending the unicast
        // DHCPREQUEST out, wait for the unicast ARP request and respond to it with ARP reply,
        // otherwise, DHCPREQUEST still cannot be sent out due to that there is no correct ARP
        // table for the dest IPv4 address.
        handler.post(() -> renewAlarm.onAlarm());
        final ArpPacket request = getNextArpPacket();
        assertArpRequest(request, SERVER_ADDR);
        sendArpReply(request.senderHwAddress.toByteArray() /* dst */, ROUTER_MAC_BYTES /* srcMac */,
                request.senderIp /* target IP */, SERVER_ADDR /* sender IP */);
        HandlerUtils.waitForIdle(handler, TEST_TIMEOUT_MS);

        // Verify there should be only one unicast DHCPREQUESTs to be received per RFC2131.
        assertReceivedDhcpRequestPacketCount();

        return rebindAlarm;
    }

    @Test @SignatureRequiredTest(reason = "Need to mock the DHCP renew/rebind alarms")
    public void testDhcpRenew() throws Exception {
        final LinkProperties lp = prepareDhcpReacquireTest();
        final InOrder inOrder = inOrder(mAlarm);
        runDhcpRenewTest(mDependencies.mDhcpClient.getHandler(), lp, inOrder);
    }

    @Test @SignatureRequiredTest(reason = "Need to mock the DHCP renew/rebind alarms")
    public void testDhcpRebind() throws Exception {
        final LinkProperties lp = prepareDhcpReacquireTest();
        final Handler handler = mDependencies.mDhcpClient.getHandler();
        final InOrder inOrder = inOrder(mAlarm);
        final OnAlarmListener rebindAlarm = runDhcpRenewTest(handler, lp, inOrder);

        // Trigger rebind alarm and forece DHCP client enter RebindingState. DHCP client sends
        // broadcast DHCPREQUEST to nearby servers, then check how many DHCPREQUEST packets are
        // retransmitted within PACKET_TIMEOUT_MS(5s), there should be only one DHCPREQUEST
        // captured per RFC2131.
        handler.post(() -> rebindAlarm.onAlarm());
        assertReceivedDhcpRequestPacketCount();
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testRestoreInitialInterfaceMtu() throws Exception {
        doRestoreInitialMtuTest(true /* shouldChangeMtu */, false /* shouldRemoveTestInterface */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testRestoreInitialInterfaceMtu_WithoutMtuChange() throws Exception {
        doRestoreInitialMtuTest(false /* shouldChangeMtu */, false /* shouldRemoveTestInterface */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testRestoreInitialInterfaceMtu_WithException() throws Exception {
        doThrow(new RemoteException("NetdNativeService::interfaceSetMtu")).when(mNetd)
                .interfaceSetMtu(mIfaceName, TEST_DEFAULT_MTU);

        doRestoreInitialMtuTest(true /* shouldChangeMtu */, false /* shouldRemoveTestInterface */);
        assertEquals(NetworkInterface.getByName(mIfaceName).getMTU(), TEST_MIN_MTU);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testRestoreInitialInterfaceMtu_NotFoundInterfaceWhenStopping() throws Exception {
        doRestoreInitialMtuTest(true /* shouldChangeMtu */, true /* shouldRemoveTestInterface */);
    }

    @Test
    public void testRestoreInitialInterfaceMtu_NotFoundInterfaceWhenStartingProvisioning()
            throws Exception {
        removeTestInterface(mTapFd);
        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIpReachabilityMonitor()
                .withoutIPv6()
                .build();

        startIpClientProvisioning(config);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningFailure(any());
        verify(mCb, never()).setNeighborDiscoveryOffload(true);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testRestoreInitialInterfaceMtu_stopIpClientAndRestart() throws Exception {
        long currentTime = System.currentTimeMillis();

        performDhcpHandshake(true /* isSuccessLease */, TEST_LEASE_DURATION_S,
                true /* isDhcpLeaseCacheEnabled */, false /* shouldReplyRapidCommitAck */,
                TEST_MIN_MTU, false /* isDhcpIpConflictDetectEnabled */);
        verifyIPv4OnlyProvisioningSuccess(Collections.singletonList(CLIENT_ADDR));
        assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, TEST_MIN_MTU);

        // Pretend that ConnectivityService set the MTU.
        mNetd.interfaceSetMtu(mIfaceName, TEST_MIN_MTU);
        assertEquals(NetworkInterface.getByName(mIfaceName).getMTU(), TEST_MIN_MTU);

        reset(mCb);
        reset(mIpMemoryStore);

        // Stop IpClient and then restart provisioning immediately.
        mIpc.stop();
        currentTime = System.currentTimeMillis();
        // Intend to set mtu option to 0, then verify that won't influence interface mtu restore.
        performDhcpHandshake(true /* isSuccessLease */, TEST_LEASE_DURATION_S,
                true /* isDhcpLeaseCacheEnabled */, false /* shouldReplyRapidCommitAck */,
                0 /* mtu */, false /* isDhcpIpConflictDetectEnabled */);
        verifyIPv4OnlyProvisioningSuccess(Collections.singletonList(CLIENT_ADDR));
        assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, 0 /* mtu */);
        assertEquals(NetworkInterface.getByName(mIfaceName).getMTU(), TEST_DEFAULT_MTU);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testRestoreInitialInterfaceMtu_removeInterfaceAndAddback() throws Exception {
        doAnswer(invocation -> {
            final LinkProperties lp = invocation.getArgument(0);
            assertEquals(lp.getInterfaceName(), mIfaceName);
            assertEquals(0, lp.getLinkAddresses().size());
            assertEquals(0, lp.getDnsServers().size());

            mDependencies.simulateInterfaceRecover();
            return null;
        }).when(mCb).onProvisioningFailure(any());

        final ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIpReachabilityMonitor()
                .withoutIPv6()
                .build();

        // Intend to remove the tap interface and force IpClient throw provisioning failure
        // due to that interface is not found.
        removeTestInterface(mTapFd);
        assertNull(InterfaceParams.getByName(mIfaceName));

        startIpClientProvisioning(config);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningFailure(any());

        // Make sure everything queued by this test was processed (e.g. transition to StoppingState
        // from ClearingIpAddressState) and tearDown will check if IpClient exits normally or crash.
        HandlerUtils.waitForIdle(mIpc.getHandler(), TEST_TIMEOUT_MS);
    }

    private boolean isIcmpv6PacketOfType(final byte[] packetBytes, int type) {
        ByteBuffer packet = ByteBuffer.wrap(packetBytes);
        return packet.getShort(ETHER_TYPE_OFFSET) == (short) ETH_P_IPV6
                && packet.get(ETHER_HEADER_LEN + IPV6_PROTOCOL_OFFSET) == (byte) IPPROTO_ICMPV6
                && packet.get(ETHER_HEADER_LEN + IPV6_HEADER_LEN) == (byte) type;
    }

    private boolean isRouterSolicitation(final byte[] packetBytes) {
        return isIcmpv6PacketOfType(packetBytes, ICMPV6_ROUTER_SOLICITATION);
    }

    private boolean isNeighborAdvertisement(final byte[] packetBytes) {
        return isIcmpv6PacketOfType(packetBytes, ICMPV6_NEIGHBOR_ADVERTISEMENT);
    }

    private boolean isNeighborSolicitation(final byte[] packetBytes) {
        return isIcmpv6PacketOfType(packetBytes, ICMPV6_NEIGHBOR_SOLICITATION);
    }

    private NeighborAdvertisement getNextNeighborAdvertisement() throws ParseException {
        final byte[] packet = mPacketReader.popPacket(PACKET_TIMEOUT_MS,
                this::isNeighborAdvertisement);
        if (packet == null) return null;

        final NeighborAdvertisement na = parseNeighborAdvertisementOrNull(packet);
        assertNotNull("Invalid neighbour advertisement received", na);
        return na;
    }

    private NeighborSolicitation getNextNeighborSolicitation() throws ParseException {
        final byte[] packet = mPacketReader.popPacket(PACKET_TIMEOUT_MS,
                this::isNeighborSolicitation);
        if (packet == null) return null;

        final NeighborSolicitation ns = parseNeighborSolicitationOrNull(packet);
        assertNotNull("Invalid neighbour solicitation received", ns);
        return ns;
    }

    private void waitForRouterSolicitation() throws ParseException {
        assertNotNull("No router solicitation received on interface within timeout",
                mPacketReader.popPacket(PACKET_TIMEOUT_MS, this::isRouterSolicitation));
    }

    private void sendRouterAdvertisement(boolean waitForRs, short lifetime, int valid,
            int preferred) throws Exception {
        final ByteBuffer pio = buildPioOption(valid, preferred, "2001:db8:1::/64");
        final ByteBuffer rdnss = buildRdnssOption(3600, IPV6_OFF_LINK_DNS_SERVER);
        sendRouterAdvertisement(waitForRs, lifetime, pio, rdnss);
    }

    private void sendRouterAdvertisement(boolean waitForRs, short lifetime,
            ByteBuffer... options) throws Exception {
        final ByteBuffer ra = buildRaPacket(lifetime, options);
        if (waitForRs) {
            waitForRouterSolicitation();
        }
        mPacketReader.sendResponse(ra);
    }

    private void sendBasicRouterAdvertisement(boolean waitForRs) throws Exception {
        sendRouterAdvertisement(waitForRs, (short) 1800 /* lifetime */, 3600 /* valid */,
                1800 /* preferred */);
    }

    private void sendRouterAdvertisementWithZeroRouterLifetime() throws Exception {
        sendRouterAdvertisement(false /* waitForRs */, (short) 0 /* lifetime */, 3600 /* valid */,
                1800 /* preferred */);
    }

    // TODO: move this and the following method to a common location and use them in ApfTest.
    private static ByteBuffer buildPioOption(int valid, int preferred, String prefixString)
            throws Exception {
        return PrefixInformationOption.build(new IpPrefix(prefixString),
                (byte) (PIO_FLAG_ON_LINK | PIO_FLAG_AUTONOMOUS), valid, preferred);
    }

    private static ByteBuffer buildRdnssOption(int lifetime, String... servers) throws Exception {
        return RdnssOption.build(lifetime, servers);
    }

    private static ByteBuffer buildSllaOption() throws Exception {
        return LlaOption.build((byte) ICMPV6_ND_OPTION_SLLA, ROUTER_MAC);
    }

    private static ByteBuffer buildRaPacket(short lifetime, ByteBuffer... options)
            throws Exception {
        final MacAddress dstMac =
                NetworkStackUtils.ipv6MulticastToEthernetMulticast(IPV6_ADDR_ALL_ROUTERS_MULTICAST);
        return Ipv6Utils.buildRaPacket(ROUTER_MAC /* srcMac */, dstMac,
                ROUTER_LINK_LOCAL /* srcIp */, IPV6_ADDR_ALL_NODES_MULTICAST /* dstIp */,
                (byte) 0 /* M=0, O=0 */, lifetime, 0 /* Reachable time, unspecified */,
                100 /* Retrans time 100ms */, options);
    }

    private static ByteBuffer buildRaPacket(ByteBuffer... options) throws Exception {
        return buildRaPacket((short) 1800, options);
    }

    private void disableIpv6ProvisioningDelays() throws Exception {
        // Speed up the test by disabling DAD and removing router_solicitation_delay.
        // We don't need to restore the default value because the interface is removed in tearDown.
        // TODO: speed up further by not waiting for RS but keying off first IPv6 packet.
        mNetd.setProcSysNet(INetd.IPV6, INetd.CONF, mIfaceName, "router_solicitation_delay", "0");
        mNetd.setProcSysNet(INetd.IPV6, INetd.CONF, mIfaceName, "dad_transmits", "0");
    }

    private void assertHasAddressThat(String msg, LinkProperties lp,
            Predicate<LinkAddress> condition) {
        for (LinkAddress addr : lp.getLinkAddresses()) {
            if (condition.test(addr)) {
                return;
            }
        }
        fail(msg + " not found in: " + lp);
    }

    private boolean hasFlag(LinkAddress addr, int flag) {
        return (addr.getFlags() & flag) == flag;
    }

    private boolean isPrivacyAddress(LinkAddress addr) {
        return addr.isGlobalPreferred() && hasFlag(addr, IFA_F_TEMPORARY);
    }

    private boolean isStablePrivacyAddress(LinkAddress addr) {
        // The Q netd does not understand the IFA_F_STABLE_PRIVACY flag.
        // See r.android.com/1295670.
        final int flag = (mIsNetlinkEventParseEnabled || ShimUtils.isAtLeastR())
                ? IFA_F_STABLE_PRIVACY : 0;
        return addr.isGlobalPreferred() && hasFlag(addr, flag);
    }

    private LinkProperties doIpv6OnlyProvisioning() throws Exception {
        final InOrder inOrder = inOrder(mCb);
        final ByteBuffer pio = buildPioOption(3600, 1800, "2001:db8:1::/64");
        final ByteBuffer rdnss = buildRdnssOption(3600, IPV6_OFF_LINK_DNS_SERVER);
        final ByteBuffer slla = buildSllaOption();
        final ByteBuffer ra = buildRaPacket(pio, rdnss, slla);

        return doIpv6OnlyProvisioning(inOrder, ra);
    }

    private LinkProperties doIpv6OnlyProvisioning(InOrder inOrder, ByteBuffer ra) throws Exception {
        waitForRouterSolicitation();
        mPacketReader.sendResponse(ra);

        // The lambda below needs to write a LinkProperties to a local variable, but lambdas cannot
        // write to non-final local variables. So declare a final variable to write to.
        final AtomicReference<LinkProperties> lpRef = new AtomicReference<>();

        ArgumentCaptor<LinkProperties> captor = ArgumentCaptor.forClass(LinkProperties.class);
        verifyWithTimeout(inOrder, mCb).onProvisioningSuccess(captor.capture());
        lpRef.set(captor.getValue());

        // Sometimes provisioning completes as soon as the link-local and the stable address appear,
        // before the privacy address appears. If so, wait here for the LinkProperties update that
        // contains all three address. Otherwise, future calls to verify() might get confused.
        if (captor.getValue().getLinkAddresses().size() == 2) {
            verifyWithTimeout(inOrder, mCb).onLinkPropertiesChange(argThat(lp -> {
                lpRef.set(lp);
                return lp.getLinkAddresses().size() == 3;
            }));
        }

        LinkProperties lp = lpRef.get();
        assertEquals("Should have 3 IPv6 addresses after provisioning: " + lp,
                3, lp.getLinkAddresses().size());
        assertHasAddressThat("link-local address", lp, x -> x.getAddress().isLinkLocalAddress());
        assertHasAddressThat("privacy address", lp, this::isPrivacyAddress);
        assertHasAddressThat("stable privacy address", lp, this::isStablePrivacyAddress);

        return lp;
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testRaRdnss() throws Exception {
        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIpReachabilityMonitor()
                .withoutIPv4()
                .build();
        startIpClientProvisioning(config);

        InOrder inOrder = inOrder(mCb);
        ArgumentCaptor<LinkProperties> captor = ArgumentCaptor.forClass(LinkProperties.class);

        final String dnsServer = "2001:4860:4860::64";
        final String lowlifeDnsServer = "2001:4860:4860::6464";

        final ByteBuffer pio = buildPioOption(600, 300, "2001:db8:1::/64");
        ByteBuffer rdnss1 = buildRdnssOption(60, lowlifeDnsServer);
        ByteBuffer rdnss2 = buildRdnssOption(600, dnsServer);
        ByteBuffer ra = buildRaPacket(pio, rdnss1, rdnss2);

        LinkProperties lp = doIpv6OnlyProvisioning(inOrder, ra);

        // Expect that DNS servers with lifetimes below CONFIG_MIN_RDNSS_LIFETIME are not accepted.
        assertNotNull(lp);
        assertEquals(1, lp.getDnsServers().size());
        assertTrue(lp.getDnsServers().contains(InetAddress.getByName(dnsServer)));

        // If the RDNSS lifetime is above the minimum, the DNS server is accepted.
        rdnss1 = buildRdnssOption(68, lowlifeDnsServer);
        ra = buildRaPacket(pio, rdnss1, rdnss2);
        mPacketReader.sendResponse(ra);
        inOrder.verify(mCb, timeout(TEST_TIMEOUT_MS)).onLinkPropertiesChange(captor.capture());
        lp = captor.getValue();
        assertNotNull(lp);
        assertEquals(2, lp.getDnsServers().size());
        assertTrue(lp.getDnsServers().contains(InetAddress.getByName(dnsServer)));
        assertTrue(lp.getDnsServers().contains(InetAddress.getByName(lowlifeDnsServer)));

        // Expect that setting RDNSS lifetime of 0 causes loss of provisioning.
        rdnss1 = buildRdnssOption(0, dnsServer);
        rdnss2 = buildRdnssOption(0, lowlifeDnsServer);
        ra = buildRaPacket(pio, rdnss1, rdnss2);
        mPacketReader.sendResponse(ra);

        inOrder.verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningFailure(captor.capture());
        lp = captor.getValue();
        assertNotNull(lp);
        assertEquals(0, lp.getDnsServers().size());
        reset(mCb);
    }

    private void runRaRdnssIpv6LinkLocalDnsTest(boolean isIpv6LinkLocalDnsAccepted)
            throws Exception {
        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIpReachabilityMonitor()
                .withoutIPv4()
                .build();
        setFeatureEnabled(NetworkStackUtils.IPCLIENT_ACCEPT_IPV6_LINK_LOCAL_DNS_VERSION,
                isIpv6LinkLocalDnsAccepted /* default value */);
        startIpClientProvisioning(config);

        final ByteBuffer pio = buildPioOption(600, 300, "2001:db8:1::/64");
        // put an IPv6 link-local DNS server
        final ByteBuffer rdnss = buildRdnssOption(600, ROUTER_LINK_LOCAL.getHostAddress());
        // put SLLA option to avoid address resolution for "fe80::1"
        final ByteBuffer slla = buildSllaOption();
        final ByteBuffer ra = buildRaPacket(pio, rdnss, slla);

        waitForRouterSolicitation();
        mPacketReader.sendResponse(ra);
    }

    @Test
    public void testRaRdnss_Ipv6LinkLocalDns() throws Exception {
        runRaRdnssIpv6LinkLocalDnsTest(true /* isIpv6LinkLocalDnsAccepted */);
        final ArgumentCaptor<LinkProperties> captor = ArgumentCaptor.forClass(LinkProperties.class);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningSuccess(captor.capture());
        final LinkProperties lp = captor.getValue();
        assertNotNull(lp);
        assertEquals(1, lp.getDnsServers().size());
        assertEquals(ROUTER_LINK_LOCAL, (Inet6Address) lp.getDnsServers().get(0));
        assertTrue(lp.isIpv6Provisioned());
    }

    @Test
    public void testRaRdnss_disableIpv6LinkLocalDns() throws Exception {
        // Only run the test when the flag of parsing netlink events is enabled, feature flag
        // "ipclient_accept_ipv6_link_local_dns" doesn't affect the legacy code.
        assumeTrue(mIsNetlinkEventParseEnabled);
        runRaRdnssIpv6LinkLocalDnsTest(false /* isIpv6LinkLocalDnsAccepted */);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onLinkPropertiesChange(argThat(lp -> {
            return lp.hasGlobalIpv6Address()
                    && lp.hasIpv6DefaultRoute()
                    && !lp.hasIpv6DnsServer();
        }));
        verify(mCb, never()).onProvisioningSuccess(any());
    }

    private void expectNat64PrefixUpdate(InOrder inOrder, IpPrefix expected) throws Exception {
        inOrder.verify(mCb, timeout(TEST_TIMEOUT_MS)).onLinkPropertiesChange(
                argThat(lp -> Objects.equals(expected, lp.getNat64Prefix())));

    }

    private void expectNoNat64PrefixUpdate(InOrder inOrder, IpPrefix unchanged) throws Exception {
        inOrder.verify(mCb, timeout(TEST_TIMEOUT_MS).times(0)).onLinkPropertiesChange(argThat(
                lp -> !Objects.equals(unchanged, lp.getNat64Prefix())));

    }

    @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
    @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testPref64Option() throws Exception {
        assumeTrue(ConstantsShim.VERSION > Build.VERSION_CODES.Q);

        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIpReachabilityMonitor()
                .withoutIPv4()
                .build();
        startIpClientProvisioning(config);

        final IpPrefix prefix = new IpPrefix("64:ff9b::/96");
        final IpPrefix otherPrefix = new IpPrefix("2001:db8:64::/96");

        final ByteBuffer pio = buildPioOption(600, 300, "2001:db8:1::/64");
        ByteBuffer rdnss = buildRdnssOption(600, IPV6_OFF_LINK_DNS_SERVER);
        ByteBuffer pref64 = new StructNdOptPref64(prefix, 600).toByteBuffer();
        ByteBuffer ra = buildRaPacket(pio, rdnss, pref64);

        // The NAT64 prefix might be detected before or after provisioning success.
        // Don't test order between these two events.
        LinkProperties lp = doIpv6OnlyProvisioning(null /*inOrder*/, ra);
        expectAlarmSet(null /*inOrder*/, "PREF64", 600);

        // From now on expect events in order.
        InOrder inOrder = inOrder(mCb, mAlarm);
        if (lp.getNat64Prefix() != null) {
            assertEquals(prefix, lp.getNat64Prefix());
        } else {
            expectNat64PrefixUpdate(inOrder, prefix);
        }

        // Increase the lifetime and expect the prefix not to change.
        pref64 = new StructNdOptPref64(prefix, 1800).toByteBuffer();
        ra = buildRaPacket(pio, rdnss, pref64);
        mPacketReader.sendResponse(ra);
        OnAlarmListener pref64Alarm = expectAlarmSet(inOrder, "PREF64", 1800);
        expectNoNat64PrefixUpdate(inOrder, prefix);
        reset(mCb, mAlarm);

        // Reduce the lifetime and expect to reschedule expiry.
        pref64 = new StructNdOptPref64(prefix, 1500).toByteBuffer();
        ra = buildRaPacket(pio, rdnss, pref64);
        mPacketReader.sendResponse(ra);
        pref64Alarm = expectAlarmSet(inOrder, "PREF64", 1496);
        expectNoNat64PrefixUpdate(inOrder, prefix);
        reset(mCb, mAlarm);

        // Withdraw the prefix and expect it to be set to null.
        pref64 = new StructNdOptPref64(prefix, 0).toByteBuffer();
        ra = buildRaPacket(pio, rdnss, pref64);
        mPacketReader.sendResponse(ra);
        expectAlarmCancelled(inOrder, pref64Alarm);
        expectNat64PrefixUpdate(inOrder, null);
        reset(mCb, mAlarm);

        // Re-announce the prefix.
        pref64 = new StructNdOptPref64(prefix, 600).toByteBuffer();
        ra = buildRaPacket(pio, rdnss, pref64);
        mPacketReader.sendResponse(ra);
        expectAlarmSet(inOrder, "PREF64", 600);
        expectNat64PrefixUpdate(inOrder, prefix);
        reset(mCb, mAlarm);

        // Announce two prefixes. Don't expect any update because if there is already a NAT64
        // prefix, any new prefix is ignored.
        ByteBuffer otherPref64 = new StructNdOptPref64(otherPrefix, 1200).toByteBuffer();
        ra = buildRaPacket(pio, rdnss, pref64, otherPref64);
        mPacketReader.sendResponse(ra);
        expectAlarmSet(inOrder, "PREF64", 600);
        expectNoNat64PrefixUpdate(inOrder, prefix);
        reset(mCb, mAlarm);

        // Withdraw the old prefix and continue to announce the new one. Expect a prefix change.
        pref64 = new StructNdOptPref64(prefix, 0).toByteBuffer();
        ra = buildRaPacket(pio, rdnss, pref64, otherPref64);
        mPacketReader.sendResponse(ra);
        expectAlarmCancelled(inOrder, pref64Alarm);
        // Need a different OnAlarmListener local variable because posting it to the handler in the
        // lambda below requires it to be final.
        final OnAlarmListener lastAlarm = expectAlarmSet(inOrder, "PREF64", 1200);
        expectNat64PrefixUpdate(inOrder, otherPrefix);
        reset(mCb, mAlarm);

        // Simulate prefix expiry.
        mIpc.getHandler().post(() -> lastAlarm.onAlarm());
        expectAlarmCancelled(inOrder, pref64Alarm);
        expectNat64PrefixUpdate(inOrder, null);

        // Announce a non-/96 prefix and expect it to be ignored.
        IpPrefix invalidPrefix = new IpPrefix("64:ff9b::/64");
        pref64 = new StructNdOptPref64(invalidPrefix, 1200).toByteBuffer();
        ra = buildRaPacket(pio, rdnss, pref64);
        mPacketReader.sendResponse(ra);
        expectNoNat64PrefixUpdate(inOrder, invalidPrefix);

        // Re-announce the prefix.
        pref64 = new StructNdOptPref64(prefix, 600).toByteBuffer();
        ra = buildRaPacket(pio, rdnss, pref64);
        mPacketReader.sendResponse(ra);
        final OnAlarmListener clearAlarm = expectAlarmSet(inOrder, "PREF64", 600);
        expectNat64PrefixUpdate(inOrder, prefix);
        reset(mCb, mAlarm);

        // Check that the alarm is cancelled when IpClient is stopped.
        mIpc.stop();
        HandlerUtils.waitForIdle(mIpc.getHandler(), TEST_TIMEOUT_MS);
        expectAlarmCancelled(inOrder, clearAlarm);
        expectNat64PrefixUpdate(inOrder, null);

        // Check that even if the alarm was already in the message queue while it was cancelled, it
        // is safely ignored.
        mIpc.getHandler().post(() -> clearAlarm.onAlarm());
        HandlerUtils.waitForIdle(mIpc.getHandler(), TEST_TIMEOUT_MS);
    }

    private void waitForAddressViaNetworkObserver(final String iface, final String addr1,
            final String addr2, int prefixLength) throws Exception {
        final CountDownLatch latch = new CountDownLatch(1);

        // Add two IPv4 addresses to the specified interface, and proceed when the NetworkObserver
        // has seen the second one. This ensures that every other NetworkObserver registered with
        // mNetworkObserverRegistry - in particular, IpClient's - has seen the addition of the first
        // address.
        final LinkAddress trigger = new LinkAddress(addr2 + "/" + prefixLength);
        NetworkObserver observer = new NetworkObserver() {
            @Override
            public void onInterfaceAddressUpdated(LinkAddress address, String ifName) {
                if (ifName.equals(iface) && address.isSameAddressAs(trigger)) {
                    latch.countDown();
                }
            }
        };

        mNetworkObserverRegistry.registerObserverForNonblockingCallback(observer);
        try {
            mNetd.interfaceAddAddress(iface, addr1, prefixLength);
            mNetd.interfaceAddAddress(iface, addr2, prefixLength);
            assertTrue("Trigger IP address " + addr2 + " not seen after " + TEST_TIMEOUT_MS + "ms",
                    latch.await(TEST_TIMEOUT_MS, TimeUnit.MILLISECONDS));
        } finally {
            mNetworkObserverRegistry.unregisterObserver(observer);
        }
    }

    private void addIpAddressAndWaitForIt(final String iface) throws Exception {
        final String addr1 = "192.0.2.99";
        final String addr2 = "192.0.2.3";
        final int prefixLength = 26;

        if (!mIsNetlinkEventParseEnabled) {
            waitForAddressViaNetworkObserver(iface, addr1, addr2, prefixLength);
        } else {
            // IpClient gets IP addresses directly from netlink instead of from netd, unnecessary
            // to rely on the NetworkObserver callbacks to confirm new added address update. Just
            // add the addresses directly and wait to see if IpClient has seen the address
            mNetd.interfaceAddAddress(iface, addr1, prefixLength);
            mNetd.interfaceAddAddress(iface, addr2, prefixLength);
        }

        // Wait for IpClient to process the addition of the address.
        HandlerUtils.waitForIdle(mIpc.getHandler(), TEST_TIMEOUT_MS);
    }

    private void doIPv4OnlyProvisioningAndExitWithLeftAddress() throws Exception {
        final long currentTime = System.currentTimeMillis();
        performDhcpHandshake(true /* isSuccessLease */, TEST_LEASE_DURATION_S,
                true /* isDhcpLeaseCacheEnabled */, false /* shouldReplyRapidCommitAck */,
                TEST_DEFAULT_MTU, false /* isDhcpIpConflictDetectEnabled */);
        verifyIPv4OnlyProvisioningSuccess(Collections.singletonList(CLIENT_ADDR));
        assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, TEST_DEFAULT_MTU);

        // Stop IpClient and expect a final LinkProperties callback with an empty LP.
        mIIpClient.stop();
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onLinkPropertiesChange(argThat(
                x -> x.getAddresses().size() == 0
                        && x.getRoutes().size() == 0
                        && x.getDnsServers().size() == 0));
        reset(mCb);

        // Pretend that something else (e.g., Tethering) used the interface and left an IP address
        // configured on it. When IpClient starts, it must clear this address before proceeding.
        // The address must be noticed before startProvisioning is called, or IpClient will
        // immediately declare provisioning success due to the presence of an IPv4 address.
        // The address must be IPv4 because IpClient clears IPv6 addresses on startup.
        addIpAddressAndWaitForIt(mIfaceName);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testIpClientClearingIpAddressState() throws Exception {
        doIPv4OnlyProvisioningAndExitWithLeftAddress();

        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIpReachabilityMonitor()
                .build();
        startIpClientProvisioning(config);

        sendBasicRouterAdvertisement(true /*waitForRs*/);

        // Check that the IPv4 addresses configured earlier are not in LinkProperties...
        ArgumentCaptor<LinkProperties> captor = ArgumentCaptor.forClass(LinkProperties.class);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningSuccess(captor.capture());
        assertFalse(captor.getValue().hasIpv4Address());

        // ... or configured on the interface.
        InterfaceConfigurationParcel cfg = mNetd.interfaceGetCfg(mIfaceName);
        assertEquals("0.0.0.0", cfg.ipv4Addr);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testIpClientClearingIpAddressState_enablePreconnection() throws Exception {
        doIPv4OnlyProvisioningAndExitWithLeftAddress();

        // Enter ClearingIpAddressesState to clear the remaining IPv4 addresses and transition to
        // PreconnectionState instead of RunningState.
        startIpClientProvisioning(false /* isDhcpLeaseCacheEnabled */,
                false /* shouldReplyRapidCommitAck */, true /* isDhcpPreConnectionEnabled */,
                false /* isDhcpIpConflictDetectEnabled */, false /* isIPv6OnlyPreferredEnabled */);
        assertDiscoverPacketOnPreconnectionStart();

        // Force to enter RunningState.
        mIpc.notifyPreconnectionComplete(false /* abort */);
        HandlerUtils.waitForIdle(mIpc.getHandler(), TEST_TIMEOUT_MS);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpClientPreconnection_success() throws Exception {
        doIpClientProvisioningWithPreconnectionTest(true /* shouldReplyRapidCommitAck */,
                false /* shouldAbortPreconnection */, false /* shouldFirePreconnectionTimeout */,
                false /* timeoutBeforePreconnectionComplete */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpClientPreconnection_SuccessWithoutRapidCommit() throws Exception {
        doIpClientProvisioningWithPreconnectionTest(false /* shouldReplyRapidCommitAck */,
                false /* shouldAbortPreconnection */, false /* shouldFirePreconnectionTimeout */,
                false /* timeoutBeforePreconnectionComplete */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpClientPreconnection_Abort() throws Exception {
        doIpClientProvisioningWithPreconnectionTest(true /* shouldReplyRapidCommitAck */,
                true /* shouldAbortPreconnection */, false /* shouldFirePreconnectionTimeout */,
                false /* timeoutBeforePreconnectionComplete */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpClientPreconnection_AbortWithoutRapiCommit() throws Exception {
        doIpClientProvisioningWithPreconnectionTest(false /* shouldReplyRapidCommitAck */,
                true /* shouldAbortPreconnection */, false /* shouldFirePreconnectionTimeout */,
                false /* timeoutBeforePreconnectionComplete */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpClientPreconnection_TimeoutBeforeAbort() throws Exception {
        doIpClientProvisioningWithPreconnectionTest(true /* shouldReplyRapidCommitAck */,
                true /* shouldAbortPreconnection */, true /* shouldFirePreconnectionTimeout */,
                true /* timeoutBeforePreconnectionComplete */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpClientPreconnection_TimeoutBeforeAbortWithoutRapidCommit()
            throws Exception {
        doIpClientProvisioningWithPreconnectionTest(false /* shouldReplyRapidCommitAck */,
                true /* shouldAbortPreconnection */, true /* shouldFirePreconnectionTimeout */,
                true /* timeoutBeforePreconnectionComplete */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpClientPreconnection_TimeoutafterAbort() throws Exception {
        doIpClientProvisioningWithPreconnectionTest(true /* shouldReplyRapidCommitAck */,
                true /* shouldAbortPreconnection */, true /* shouldFirePreconnectionTimeout */,
                false /* timeoutBeforePreconnectionComplete */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpClientPreconnection_TimeoutAfterAbortWithoutRapidCommit() throws Exception {
        doIpClientProvisioningWithPreconnectionTest(false /* shouldReplyRapidCommitAck */,
                true /* shouldAbortPreconnection */, true /* shouldFirePreconnectionTimeout */,
                false /* timeoutBeforePreconnectionComplete */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpClientPreconnection_TimeoutBeforeSuccess() throws Exception {
        doIpClientProvisioningWithPreconnectionTest(true /* shouldReplyRapidCommitAck */,
                false /* shouldAbortPreconnection */, true /* shouldFirePreconnectionTimeout */,
                true /* timeoutBeforePreconnectionComplete */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpClientPreconnection_TimeoutBeforeSuccessWithoutRapidCommit()
            throws Exception {
        doIpClientProvisioningWithPreconnectionTest(false /* shouldReplyRapidCommitAck */,
                false /* shouldAbortPreconnection */, true /* shouldFirePreconnectionTimeout */,
                true /* timeoutBeforePreconnectionComplete */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpClientPreconnection_TimeoutAfterSuccess() throws Exception {
        doIpClientProvisioningWithPreconnectionTest(true /* shouldReplyRapidCommitAck */,
                false /* shouldAbortPreconnection */, true /* shouldFirePreconnectionTimeout */,
                false /* timeoutBeforePreconnectionComplete */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpClientPreconnection_TimeoutAfterSuccessWithoutRapidCommit()
            throws Exception {
        doIpClientProvisioningWithPreconnectionTest(false /* shouldReplyRapidCommitAck */,
                false /* shouldAbortPreconnection */, true /* shouldFirePreconnectionTimeout */,
                false /* timeoutBeforePreconnectionComplete */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpClientPreconnection_WithoutLayer2InfoWhenStartingProv() throws Exception {
        // For FILS connection, current bssid (also l2key and cluster) is still null when
        // starting provisioning since the L2 link hasn't been established yet. Ensure that
        // IpClient won't crash even if initializing an Layer2Info class with null members.
        ProvisioningConfiguration.Builder prov = new ProvisioningConfiguration.Builder()
                .withoutIpReachabilityMonitor()
                .withoutIPv6()
                .withPreconnection()
                .withLayer2Information(new Layer2Information(null /* l2key */, null /* cluster */,
                        null /* bssid */));

        startIpClientProvisioning(prov.build());
        assertDiscoverPacketOnPreconnectionStart();
        verify(mCb).setNeighborDiscoveryOffload(true);

        // Force IpClient transition to RunningState from PreconnectionState.
        mIIpClient.notifyPreconnectionComplete(false /* success */);
        HandlerUtils.waitForIdle(mDependencies.mDhcpClient.getHandler(), TEST_TIMEOUT_MS);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).setFallbackMulticastFilter(true);
    }

    @Test
    @SignatureRequiredTest(reason = "needs mocked alarm and access to IpClient handler thread")
    public void testDhcpClientPreconnection_DelayedAbortAndTransitToStoppedState()
            throws Exception {
        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIpReachabilityMonitor()
                .withPreconnection()
                .build();
        setDhcpFeatures(false /* isDhcpLeaseCacheEnabled */, false /* shouldReplyRapidCommitAck */,
                false /* isDhcpIpConflictDetectEnabled */, false /* isIPv6OnlyPreferredEnabled */);
        startIpClientProvisioning(config);
        assertDiscoverPacketOnPreconnectionStart();

        // IpClient is in the PreconnectingState, simulate provisioning timeout event
        // and force IpClient state machine transit to StoppingState.
        final ArgumentCaptor<LinkProperties> captor = ArgumentCaptor.forClass(LinkProperties.class);
        final OnAlarmListener alarm = expectAlarmSet(null /* inOrder */, "TIMEOUT", 18,
                mIpc.getHandler());
        mIpc.getHandler().post(() -> alarm.onAlarm());

        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningFailure(captor.capture());
        final LinkProperties lp = captor.getValue();
        assertNotNull(lp);
        assertEquals(mIfaceName, lp.getInterfaceName());
        assertEquals(0, lp.getLinkAddresses().size());
        assertEquals(0, lp.getRoutes().size());
        assertEquals(0, lp.getMtu());
        assertEquals(0, lp.getDnsServers().size());

        // Send preconnection abort message, but IpClient should ignore it at this moment and
        // transit to StoppedState finally.
        mIpc.notifyPreconnectionComplete(false /* abort */);
        mIpc.stop();
        HandlerUtils.waitForIdle(mIpc.getHandler(), TEST_TIMEOUT_MS);

        reset(mCb);

        // Start provisioning again to verify IpClient can process CMD_START correctly at
        // StoppedState.
        startIpClientProvisioning(false /* isDhcpLeaseCacheEnabled */,
                false /* shouldReplyRapidCommitAck */, false /* isPreConnectionEnabled */,
                false /* isDhcpIpConflictDetectEnabled */, false /* isIPv6OnlyPreferredEnabled */);
        final DhcpPacket discover = getNextDhcpPacket();
        assertTrue(discover instanceof DhcpDiscoverPacket);
    }

    @Test
    public void testDhcpDecline_conflictByArpReply() throws Exception {
        doIpAddressConflictDetectionTest(true /* causeIpAddressConflict */,
                false /* shouldReplyRapidCommitAck */, true /* isDhcpIpConflictDetectEnabled */,
                true /* shouldResponseArpReply */);
    }

    @Test
    public void testDhcpDecline_conflictByArpProbe() throws Exception {
        doIpAddressConflictDetectionTest(true /* causeIpAddressConflict */,
                false /* shouldReplyRapidCommitAck */, true /* isDhcpIpConflictDetectEnabled */,
                false /* shouldResponseArpReply */);
    }

    @Test
    public void testDhcpDecline_EnableFlagWithoutIpConflict() throws Exception {
        doIpAddressConflictDetectionTest(false /* causeIpAddressConflict */,
                false /* shouldReplyRapidCommitAck */, true /* isDhcpIpConflictDetectEnabled */,
                false /* shouldResponseArpReply */);
    }

    @Test
    public void testDhcpDecline_WithoutIpConflict() throws Exception {
        doIpAddressConflictDetectionTest(false /* causeIpAddressConflict */,
                false /* shouldReplyRapidCommitAck */, false /* isDhcpIpConflictDetectEnabled */,
                false /* shouldResponseArpReply */);
    }

    @Test
    public void testDhcpDecline_WithRapidCommitWithoutIpConflict() throws Exception {
        doIpAddressConflictDetectionTest(false /* causeIpAddressConflict */,
                true /* shouldReplyRapidCommitAck */, false /* isDhcpIpConflictDetectEnabled */,
                false /* shouldResponseArpReply */);
    }

    @Test
    public void testDhcpDecline_WithRapidCommitConflictByArpReply() throws Exception {
        doIpAddressConflictDetectionTest(true /* causeIpAddressConflict */,
                true /* shouldReplyRapidCommitAck */, true /* isDhcpIpConflictDetectEnabled */,
                true /* shouldResponseArpReply */);
    }

    @Test
    public void testDhcpDecline_WithRapidCommitConflictByArpProbe() throws Exception {
        doIpAddressConflictDetectionTest(true /* causeIpAddressConflict */,
                true /* shouldReplyRapidCommitAck */, true /* isDhcpIpConflictDetectEnabled */,
                false /* shouldResponseArpReply */);
    }

    @Test
    public void testDhcpDecline_EnableFlagWithRapidCommitWithoutIpConflict() throws Exception {
        doIpAddressConflictDetectionTest(false /* causeIpAddressConflict */,
                true /* shouldReplyRapidCommitAck */, true /* isDhcpIpConflictDetectEnabled */,
                false /* shouldResponseArpReply */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testHostname_enableConfig() throws Exception {
        mDependencies.setHostnameConfiguration(true /* isHostnameConfigurationEnabled */,
                TEST_HOST_NAME);

        final long currentTime = System.currentTimeMillis();
        final List<DhcpPacket> sentPackets = performDhcpHandshake(true /* isSuccessLease */,
                TEST_LEASE_DURATION_S, true /* isDhcpLeaseCacheEnabled */,
                false /* isDhcpRapidCommitEnabled */, TEST_DEFAULT_MTU,
                false /* isDhcpIpConflictDetectEnabled */);

        assertEquals(2, sentPackets.size());
        verifyIPv4OnlyProvisioningSuccess(Collections.singletonList(CLIENT_ADDR));
        assertHostname(true, TEST_HOST_NAME, TEST_HOST_NAME_TRANSLITERATION, sentPackets);
        assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, TEST_DEFAULT_MTU);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testHostname_disableConfig() throws Exception {
        mDependencies.setHostnameConfiguration(false /* isHostnameConfigurationEnabled */,
                TEST_HOST_NAME);

        final long currentTime = System.currentTimeMillis();
        final List<DhcpPacket> sentPackets = performDhcpHandshake(true /* isSuccessLease */,
                TEST_LEASE_DURATION_S, true /* isDhcpLeaseCacheEnabled */,
                false /* isDhcpRapidCommitEnabled */, TEST_DEFAULT_MTU,
                false /* isDhcpIpConflictDetectEnabled */);

        assertEquals(2, sentPackets.size());
        verifyIPv4OnlyProvisioningSuccess(Collections.singletonList(CLIENT_ADDR));
        assertHostname(false, TEST_HOST_NAME, TEST_HOST_NAME_TRANSLITERATION, sentPackets);
        assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, TEST_DEFAULT_MTU);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testHostname_enableConfigWithNullHostname() throws Exception {
        mDependencies.setHostnameConfiguration(true /* isHostnameConfigurationEnabled */,
                null /* hostname */);

        final long currentTime = System.currentTimeMillis();
        final List<DhcpPacket> sentPackets = performDhcpHandshake(true /* isSuccessLease */,
                TEST_LEASE_DURATION_S, true /* isDhcpLeaseCacheEnabled */,
                false /* isDhcpRapidCommitEnabled */, TEST_DEFAULT_MTU,
                false /* isDhcpIpConflictDetectEnabled */);

        assertEquals(2, sentPackets.size());
        verifyIPv4OnlyProvisioningSuccess(Collections.singletonList(CLIENT_ADDR));
        assertHostname(true, null /* hostname */, null /* hostnameAfterTransliteration */,
                sentPackets);
        assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, TEST_DEFAULT_MTU);
    }

    private LinkProperties runDhcpClientCaptivePortalApiTest(boolean featureEnabled,
            boolean serverSendsOption) throws Exception {
        startIpClientProvisioning(false /* isDhcpLeaseCacheEnabled */,
                false /* shouldReplyRapidCommitAck */, false /* isPreConnectionEnabled */,
                false /* isDhcpIpConflictDetectEnabled */, false /* isIPv6OnlyPreferredEnabled */);
        final DhcpPacket discover = getNextDhcpPacket();
        assertTrue(discover instanceof DhcpDiscoverPacket);
        assertEquals(featureEnabled, discover.hasRequestedParam(DhcpPacket.DHCP_CAPTIVE_PORTAL));

        // Send Offer and handle Request -> Ack
        final String serverSentUrl = serverSendsOption ? TEST_CAPTIVE_PORTAL_URL : null;
        mPacketReader.sendResponse(buildDhcpOfferPacket(discover, CLIENT_ADDR,
                TEST_LEASE_DURATION_S, (short) TEST_DEFAULT_MTU, serverSentUrl));
        final int testMtu = 1345;
        handleDhcpPackets(true /* isSuccessLease */, TEST_LEASE_DURATION_S,
                false /* shouldReplyRapidCommitAck */, testMtu, serverSentUrl);

        final Uri expectedUrl = featureEnabled && serverSendsOption
                ? Uri.parse(TEST_CAPTIVE_PORTAL_URL) : null;
        // LinkProperties will be updated multiple times. Wait for it to contain DHCP-obtained info,
        // such as MTU.
        final ArgumentCaptor<LinkProperties> captor = ArgumentCaptor.forClass(LinkProperties.class);
        verify(mCb, timeout(TEST_TIMEOUT_MS).atLeastOnce()).onLinkPropertiesChange(
                argThat(lp -> lp.getMtu() == testMtu));

        // Ensure that the URL was set as expected in the callbacks.
        // Can't verify the URL up to Q as there is no such attribute in LinkProperties.
        if (!ShimUtils.isAtLeastR()) return null;
        verify(mCb, atLeastOnce()).onLinkPropertiesChange(captor.capture());
        final LinkProperties expectedLp = captor.getAllValues().stream().findFirst().get();
        assertNotNull(expectedLp);
        assertEquals(expectedUrl, expectedLp.getCaptivePortalApiUrl());
        return expectedLp;
    }

    @Test
    public void testDhcpClientCaptivePortalApiEnabled() throws Exception {
        // Only run the test on platforms / builds where the API is enabled
        assumeTrue(CaptivePortalDataShimImpl.isSupported());
        runDhcpClientCaptivePortalApiTest(true /* featureEnabled */, true /* serverSendsOption */);
    }

    @Test
    public void testDhcpClientCaptivePortalApiEnabled_NoUrl() throws Exception {
        // Only run the test on platforms / builds where the API is enabled
        assumeTrue(CaptivePortalDataShimImpl.isSupported());
        runDhcpClientCaptivePortalApiTest(true /* featureEnabled */, false /* serverSendsOption */);
    }

    @Test
    public void testDhcpClientCaptivePortalApiEnabled_ParcelSensitiveFields() throws Exception {
        // Only run the test on platforms / builds where the API is enabled
        assumeTrue(CaptivePortalDataShimImpl.isSupported());
        LinkProperties lp = runDhcpClientCaptivePortalApiTest(true /* featureEnabled */,
                true /* serverSendsOption */);

        // Integration test process runs in the same process with network stack module, there
        // won't be any IPC call happened on IpClientCallbacks, manually run parcelingRoundTrip
        // to parcel and unparcel the LinkProperties to simulate what happens during the binder
        // call. In this case lp should contain the senstive data but mParcelSensitiveFields is
        // false after round trip.
        if (useNetworkStackSignature()) {
            lp = parcelingRoundTrip(lp);
        }
        final Uri expectedUrl = Uri.parse(TEST_CAPTIVE_PORTAL_URL);
        assertEquals(expectedUrl, lp.getCaptivePortalApiUrl());

        // Parcel and unparcel the captured LinkProperties, mParcelSensitiveFields is false,
        // CaptivePortalApiUrl should be null after parceling round trip.
        final LinkProperties unparceled = parcelingRoundTrip(lp);
        assertNull(unparceled.getCaptivePortalApiUrl());
    }

    @Test
    public void testDhcpClientCaptivePortalApiDisabled() throws Exception {
        // Only run the test on platforms / builds where the API is disabled
        assumeFalse(CaptivePortalDataShimImpl.isSupported());
        runDhcpClientCaptivePortalApiTest(false /* featureEnabled */, true /* serverSendsOption */);
    }

    private ScanResultInfo makeScanResultInfo(final int id, final String ssid,
            final String bssid, final byte[] oui, final byte type, final byte[] data) {
        final ByteBuffer payload = ByteBuffer.allocate(4 + data.length);
        payload.put(oui);
        payload.put(type);
        payload.put(data);
        payload.flip();
        final ScanResultInfo.InformationElement ie =
                new ScanResultInfo.InformationElement(id /* IE id */, payload);
        return new ScanResultInfo(ssid, bssid, Collections.singletonList(ie));
    }

    private ScanResultInfo makeScanResultInfo(final int id, final byte[] oui, final byte type) {
        byte[] data = new byte[10];
        new Random().nextBytes(data);
        return makeScanResultInfo(id, TEST_DEFAULT_SSID, TEST_DEFAULT_BSSID, oui, type, data);
    }

    private ScanResultInfo makeScanResultInfo(final String ssid, final String bssid) {
        byte[] data = new byte[10];
        new Random().nextBytes(data);
        return makeScanResultInfo(0xdd, ssid, bssid, TEST_AP_OUI, (byte) 0x06, data);
    }

    private void doUpstreamHotspotDetectionTest(final int id, final String displayName,
            final String ssid, final byte[] oui, final byte type, final byte[] data,
            final boolean expectMetered) throws Exception {
        final ScanResultInfo info = makeScanResultInfo(id, ssid, TEST_DEFAULT_BSSID, oui, type,
                data);
        final long currentTime = System.currentTimeMillis();
        final List<DhcpPacket> sentPackets = performDhcpHandshake(true /* isSuccessLease */,
                TEST_LEASE_DURATION_S, true /* isDhcpLeaseCacheEnabled */,
                false /* isDhcpRapidCommitEnabled */, TEST_DEFAULT_MTU,
                false /* isDhcpIpConflictDetectEnabled */,
                false /* isIPv6OnlyPreferredEnabled */,
                null /* captivePortalApiUrl */, displayName, info /* scanResultInfo */,
                null /* layer2Info */);
        assertEquals(2, sentPackets.size());
        verifyIPv4OnlyProvisioningSuccess(Collections.singletonList(CLIENT_ADDR));

        ArgumentCaptor<DhcpResultsParcelable> captor =
                ArgumentCaptor.forClass(DhcpResultsParcelable.class);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onNewDhcpResults(captor.capture());
        final DhcpResultsParcelable lease = captor.getValue();
        assertNotNull(lease);
        assertEquals(CLIENT_ADDR, lease.baseConfiguration.getIpAddress().getAddress());
        assertEquals(SERVER_ADDR, lease.baseConfiguration.getGateway());
        assertEquals(1, lease.baseConfiguration.getDnsServers().size());
        assertTrue(lease.baseConfiguration.getDnsServers().contains(SERVER_ADDR));
        assertEquals(SERVER_ADDR, InetAddresses.parseNumericAddress(lease.serverAddress));
        assertEquals(TEST_DEFAULT_MTU, lease.mtu);

        if (expectMetered) {
            assertEquals(lease.vendorInfo, DhcpPacket.VENDOR_INFO_ANDROID_METERED);
        } else {
            assertNull(lease.vendorInfo);
        }

        assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, TEST_DEFAULT_MTU);
    }

    @Test
    public void testUpstreamHotspotDetection() throws Exception {
        byte[] data = new byte[10];
        new Random().nextBytes(data);
        doUpstreamHotspotDetectionTest(0xdd, "\"ssid\"", "ssid",
                new byte[] { (byte) 0x00, (byte) 0x17, (byte) 0xF2 }, (byte) 0x06, data,
                true /* expectMetered */);
    }

    @Test
    public void testUpstreamHotspotDetection_incorrectIeId() throws Exception {
        byte[] data = new byte[10];
        new Random().nextBytes(data);
        doUpstreamHotspotDetectionTest(0xdc, "\"ssid\"", "ssid",
                new byte[] { (byte) 0x00, (byte) 0x17, (byte) 0xF2 }, (byte) 0x06, data,
                false /* expectMetered */);
    }

    @Test
    public void testUpstreamHotspotDetection_incorrectOUI() throws Exception {
        byte[] data = new byte[10];
        new Random().nextBytes(data);
        doUpstreamHotspotDetectionTest(0xdd, "\"ssid\"", "ssid",
                new byte[] { (byte) 0x00, (byte) 0x1A, (byte) 0x11 }, (byte) 0x06, data,
                false /* expectMetered */);
    }

    @Test
    public void testUpstreamHotspotDetection_incorrectSsid() throws Exception {
        byte[] data = new byte[10];
        new Random().nextBytes(data);
        doUpstreamHotspotDetectionTest(0xdd, "\"another ssid\"", "ssid",
                new byte[] { (byte) 0x00, (byte) 0x17, (byte) 0xF2 }, (byte) 0x06, data,
                false /* expectMetered */);
    }

    @Test
    public void testUpstreamHotspotDetection_incorrectType() throws Exception {
        byte[] data = new byte[10];
        new Random().nextBytes(data);
        doUpstreamHotspotDetectionTest(0xdd, "\"ssid\"", "ssid",
                new byte[] { (byte) 0x00, (byte) 0x17, (byte) 0xF2 }, (byte) 0x0a, data,
                false /* expectMetered */);
    }

    @Test
    public void testUpstreamHotspotDetection_zeroLengthData() throws Exception {
        byte[] data = new byte[0];
        doUpstreamHotspotDetectionTest(0xdd, "\"ssid\"", "ssid",
                new byte[] { (byte) 0x00, (byte) 0x17, (byte) 0xF2 }, (byte) 0x06, data,
                true /* expectMetered */);
    }

    private void forceLayer2Roaming() throws Exception {
        final Layer2InformationParcelable roamingInfo = new Layer2InformationParcelable();
        roamingInfo.bssid = MacAddress.fromString(TEST_DHCP_ROAM_BSSID);
        roamingInfo.l2Key = TEST_DHCP_ROAM_L2KEY;
        roamingInfo.cluster = TEST_DHCP_ROAM_CLUSTER;
        mIIpClient.updateLayer2Information(roamingInfo);
    }

    private void assertDhcpRequestForReacquire(final DhcpPacket packet) {
        assertTrue(packet instanceof DhcpRequestPacket);
        assertEquals(packet.mClientIp, CLIENT_ADDR);    // client IP
        assertNull(packet.mRequestedIp);                // requested IP option
        assertNull(packet.mServerIdentifier);           // server ID
    }

    private void doDhcpRoamingTest(final boolean hasMismatchedIpAddress, final String displayName,
            final MacAddress bssid, final boolean expectRoaming,
            final boolean shouldReplyNakOnRoam) throws Exception {
        long currentTime = System.currentTimeMillis();
        final Layer2Information layer2Info = new Layer2Information(TEST_L2KEY, TEST_CLUSTER, bssid);

        doAnswer(invocation -> {
            // we don't rely on the Init-Reboot state to renew previous cached IP lease.
            // Just return null and force state machine enter INIT state.
            final String l2Key = invocation.getArgument(0);
            ((OnNetworkAttributesRetrievedListener) invocation.getArgument(1))
                    .onNetworkAttributesRetrieved(new Status(SUCCESS), l2Key, null);
            return null;
        }).when(mIpMemoryStore).retrieveNetworkAttributes(eq(TEST_L2KEY), any());

        mDependencies.setHostnameConfiguration(true /* isHostnameConfigurationEnabled */,
                null /* hostname */);
        performDhcpHandshake(true /* isSuccessLease */, TEST_LEASE_DURATION_S,
                true /* isDhcpLeaseCacheEnabled */, false /* isDhcpRapidCommitEnabled */,
                TEST_DEFAULT_MTU, false /* isDhcpIpConflictDetectEnabled */,
                false /* isIPv6OnlyPreferredEnabled */,
                null /* captivePortalApiUrl */, displayName, null /* scanResultInfo */,
                layer2Info);
        verifyIPv4OnlyProvisioningSuccess(Collections.singletonList(CLIENT_ADDR));
        assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, TEST_DEFAULT_MTU);

        // simulate the roaming by updating bssid.
        forceLayer2Roaming();

        currentTime = System.currentTimeMillis();
        reset(mIpMemoryStore);
        reset(mCb);
        if (!expectRoaming) {
            assertIpMemoryNeverStoreNetworkAttributes();
            return;
        }
        // check DHCPREQUEST broadcast sent to renew IP address.
        final DhcpPacket packet = getNextDhcpPacket();
        assertDhcpRequestForReacquire(packet);

        final ByteBuffer packetBuffer = shouldReplyNakOnRoam
                ? buildDhcpNakPacket(packet, "request IP on a wrong subnet")
                : buildDhcpAckPacket(packet,
                        hasMismatchedIpAddress ? CLIENT_ADDR_NEW : CLIENT_ADDR,
                        TEST_LEASE_DURATION_S, (short) TEST_DEFAULT_MTU,
                        false /* rapidCommit */, null /* captivePortalApiUrl */);
        mPacketReader.sendResponse(packetBuffer);
        HandlerUtils.waitForIdle(mIpc.getHandler(), TEST_TIMEOUT_MS);

        if (shouldReplyNakOnRoam) {
            ArgumentCaptor<ReachabilityLossInfoParcelable> lossInfoCaptor =
                    ArgumentCaptor.forClass(ReachabilityLossInfoParcelable.class);
            verify(mCb, timeout(TEST_TIMEOUT_MS)).onReachabilityFailure(lossInfoCaptor.capture());
            assertEquals(ReachabilityLossReason.ROAM, lossInfoCaptor.getValue().reason);

            // IPv4 address will be still deleted when DhcpClient state machine exits from
            // DhcpHaveLeaseState, a following onProvisioningFailure will be thrown then.
            // Also check DhcpClient won't send any DHCPDISCOVER packet.
            verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningFailure(any());
            assertNull(getNextDhcpPacket(TEST_TIMEOUT_MS));
            verify(mCb, never()).onNewDhcpResults(any());
        } else if (hasMismatchedIpAddress) {
            ArgumentCaptor<DhcpResultsParcelable> resultsCaptor =
                    ArgumentCaptor.forClass(DhcpResultsParcelable.class);
            verify(mCb, timeout(TEST_TIMEOUT_MS)).onNewDhcpResults(resultsCaptor.capture());
            final DhcpResultsParcelable lease = resultsCaptor.getValue();
            assertNull(lease);

            // DhcpClient rolls back to StoppedState instead of INIT state after calling
            // notifyFailure, DHCPDISCOVER should not be sent out.
            assertNull(getNextDhcpPacket(TEST_TIMEOUT_MS));
        } else {
            assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime,
                    TEST_DEFAULT_MTU);
        }
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpRoaming() throws Exception {
        doDhcpRoamingTest(false /* hasMismatchedIpAddress */, "\"0001docomo\"" /* display name */,
                MacAddress.fromString(TEST_DEFAULT_BSSID), true /* expectRoaming */,
                false /* shouldReplyNakOnRoam */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpRoaming_invalidBssid() throws Exception {
        doDhcpRoamingTest(false /* hasMismatchedIpAddress */, "\"0001docomo\"" /* display name */,
                MacAddress.fromString(TEST_DHCP_ROAM_BSSID), false /* expectRoaming */,
                false/* shouldReplyNakOnRoam */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpRoaming_nullBssid() throws Exception {
        doDhcpRoamingTest(false /* hasMismatchedIpAddress */, "\"0001docomo\"" /* display name */,
                null /* BSSID */, false /* expectRoaming */, false /* shouldReplyNakOnRoam */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpRoaming_invalidDisplayName() throws Exception {
        doDhcpRoamingTest(false /* hasMismatchedIpAddress */, "\"test-ssid\"" /* display name */,
                MacAddress.fromString(TEST_DEFAULT_BSSID), false /* expectRoaming */,
                false /* shouldReplyNakOnRoam */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpRoaming_mismatchedLeasedIpAddress() throws Exception {
        doDhcpRoamingTest(true /* hasMismatchedIpAddress */, "\"0001docomo\"" /* display name */,
                MacAddress.fromString(TEST_DEFAULT_BSSID), true /* expectRoaming */,
                false /* shouldReplyNakOnRoam */);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDhcpRoaming_failureLeaseOnNak() throws Exception {
        doDhcpRoamingTest(false /* hasMismatchedIpAddress */, "\"0001docomo\"" /* display name */,
                MacAddress.fromString(TEST_DEFAULT_BSSID), true /* expectRoaming */,
                true /* shouldReplyNakOnRoam */);
    }

    private LinkProperties performDualStackProvisioning() throws Exception {
        final Inet6Address dnsServer =
                (Inet6Address) InetAddresses.parseNumericAddress(IPV6_OFF_LINK_DNS_SERVER);
        final ByteBuffer pio = buildPioOption(3600, 1800, "2001:db8:1::/64");
        final ByteBuffer rdnss = buildRdnssOption(3600, IPV6_OFF_LINK_DNS_SERVER);
        final ByteBuffer slla = buildSllaOption();
        final ByteBuffer ra = buildRaPacket(pio, rdnss, slla);

        return performDualStackProvisioning(ra, dnsServer);
    }

    private LinkProperties performDualStackProvisioning(final ByteBuffer ra,
            final InetAddress dnsServer) throws Exception {
        final InOrder inOrder = inOrder(mCb);
        final CompletableFuture<LinkProperties> lpFuture = new CompletableFuture<>();

        // Start IPv4 provisioning first and wait IPv4 provisioning to succeed, and then start
        // IPv6 provisioning, which is more realistic and avoid the flaky case of both IPv4 and
        // IPv6 provisioning complete at the same time.
        handleDhcpPackets(true /* isSuccessLease */, TEST_LEASE_DURATION_S,
                true /* shouldReplyRapidCommitAck */, TEST_DEFAULT_MTU, null /* serverSentUrl */);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningSuccess(any());

        waitForRouterSolicitation();
        mPacketReader.sendResponse(ra);

        // Wait until we see both success IPv4 and IPv6 provisioning, then there would be 4
        // addresses in LinkProperties, they are IPv4 address, IPv6 link-local address, stable
        // privacy address and privacy address.
        verify(mCb, timeout(TEST_TIMEOUT_MS).atLeastOnce()).onLinkPropertiesChange(argThat(x -> {
            if (!x.isIpv4Provisioned() || !x.isIpv6Provisioned()) return false;
            if (x.getLinkAddresses().size() != 4) return false;
            lpFuture.complete(x);
            return true;
        }));

        final LinkProperties lp = lpFuture.get(TEST_TIMEOUT_MS, TimeUnit.MILLISECONDS);
        assertNotNull(lp);
        assertTrue(lp.getDnsServers().contains(dnsServer));
        assertTrue(lp.getDnsServers().contains(SERVER_ADDR));
        assertHasAddressThat("link-local address", lp, x -> x.getAddress().isLinkLocalAddress());
        assertHasAddressThat("privacy address", lp, this::isPrivacyAddress);
        assertHasAddressThat("stable privacy address", lp, this::isStablePrivacyAddress);

        return lp;
    }

    private void doDualStackProvisioning() throws Exception {
        final ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIpReachabilityMonitor()
                .build();

        // Enable rapid commit to accelerate DHCP handshake to shorten test duration,
        // not strictly necessary.
        setDhcpFeatures(false /* isDhcpLeaseCacheEnabled */, true /* isRapidCommitEnabled */,
                false /* isDhcpIpConflictDetectEnabled */, false /* isIPv6OnlyPreferredEnabled */);
        // Both signature and root tests can use this function to do dual-stack provisioning.
        if (useNetworkStackSignature()) {
            mIpc.startProvisioning(config);
        } else {
            mIIpClient.startProvisioning(config.toStableParcelable());
        }

        performDualStackProvisioning();
    }

    private boolean hasRouteTo(@NonNull final LinkProperties lp, @NonNull final String prefix) {
        return hasRouteTo(lp, prefix, RTN_UNICAST);
    }

    private boolean hasRouteTo(@NonNull final LinkProperties lp, @NonNull final String prefix,
            int type) {
        for (RouteInfo r : lp.getRoutes()) {
            if (r.getDestination().equals(new IpPrefix(prefix))) return r.getType() == type;
        }
        return false;
    }

    private boolean hasIpv6AddressPrefixedWith(@NonNull final LinkProperties lp,
            @NonNull final IpPrefix prefix) {
        for (LinkAddress la : lp.getLinkAddresses()) {
            final InetAddress addr = la.getAddress();
            if ((addr instanceof Inet6Address) && !addr.isLinkLocalAddress()) {
                return prefix.contains(addr);
            }
        }
        return false;
    }

    @Test
    public void testIgnoreIpv6ProvisioningLoss_disableAcceptRaDefrtr() throws Exception {
        doDualStackProvisioning();

        final CompletableFuture<LinkProperties> lpFuture = new CompletableFuture<>();

        // Send RA with 0-lifetime and wait until all global IPv6 addresses, IPv6-related default
        // route and DNS servers have been removed, then verify if there is IPv4-only, IPv6 link
        // local address and route to fe80::/64 info left in the LinkProperties.
        sendRouterAdvertisementWithZeroRouterLifetime();
        verify(mCb, timeout(TEST_TIMEOUT_MS).atLeastOnce()).onLinkPropertiesChange(
                argThat(x -> {
                    // Only IPv4 provisioned and IPv6 link-local address
                    final boolean isIPv6LinkLocalAndIPv4OnlyProvisioned =
                            (x.getLinkAddresses().size() == 2
                                    && x.getDnsServers().size() == 1
                                    && x.getAddresses().get(0) instanceof Inet4Address
                                    && x.getDnsServers().get(0) instanceof Inet4Address);

                    if (!isIPv6LinkLocalAndIPv4OnlyProvisioned) return false;
                    lpFuture.complete(x);
                    return true;
                }));
        final LinkProperties lp = lpFuture.get(TEST_TIMEOUT_MS, TimeUnit.MILLISECONDS);
        assertNotNull(lp);
        assertEquals(lp.getAddresses().get(0), CLIENT_ADDR);
        assertEquals(lp.getDnsServers().get(0), SERVER_ADDR);
        assertTrue(hasRouteTo(lp, IPV6_LINK_LOCAL_PREFIX)); // fe80::/64
        assertTrue(hasRouteTo(lp, IPV4_TEST_SUBNET_PREFIX)); // IPv4 directly-connected route
        assertTrue(hasRouteTo(lp, IPV4_ANY_ADDRESS_PREFIX)); // IPv4 default route
        assertTrue(lp.getAddresses().get(1).isLinkLocalAddress());

        clearInvocations(mCb);

        // Wait for RS after IPv6 stack has been restarted and reply with a normal RA to verify
        // that device gains the IPv6 provisioning without default route and off-link DNS server.
        sendBasicRouterAdvertisement(true /* waitForRs */);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onLinkPropertiesChange(argThat(
                x -> x.hasGlobalIpv6Address()
                        // IPv4, IPv6 link local, privacy and stable privacy
                        && x.getLinkAddresses().size() == 4
                        && !x.hasIpv6DefaultRoute()
                        && x.getDnsServers().size() == 1
                        && x.getDnsServers().get(0).equals(SERVER_ADDR)));
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDualStackProvisioning() throws Exception {
        doDualStackProvisioning();

        verify(mCb, never()).onProvisioningFailure(any());
    }

    private DhcpPacket verifyDhcpPacketRequestsIPv6OnlyPreferredOption(
            Class<? extends DhcpPacket> packetType) throws Exception {
        final DhcpPacket packet = getNextDhcpPacket();
        assertTrue(packetType.isInstance(packet));
        assertTrue(packet.hasRequestedParam(DHCP_IPV6_ONLY_PREFERRED));
        return packet;
    }

    private void doIPv6OnlyPreferredOptionTest(final Integer ipv6OnlyWaitTime,
            final Inet4Address clientAddress) throws Exception {
        final ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIpReachabilityMonitor()
                .build();
        setDhcpFeatures(false /* isDhcpLeaseCacheEnabled */, false /* isRapidCommitEnabled */,
                false /* isDhcpIpConflictDetectEnabled */, true /* isIPv6OnlyPreferredEnabled */);
        startIpClientProvisioning(config);

        final DhcpPacket packet =
                verifyDhcpPacketRequestsIPv6OnlyPreferredOption(DhcpDiscoverPacket.class);

        // Respond DHCPOFFER with IPv6-Only preferred option and offered address.
        mPacketReader.sendResponse(buildDhcpOfferPacket(packet, clientAddress,
                TEST_LEASE_DURATION_S, (short) TEST_DEFAULT_MTU, null /* captivePortalUrl */,
                ipv6OnlyWaitTime));
    }

    private void doDiscoverIPv6OnlyPreferredOptionTest(final int optionSecs,
            final long expectedWaitSecs) throws Exception {
        doIPv6OnlyPreferredOptionTest(optionSecs, CLIENT_ADDR);
        final OnAlarmListener alarm = expectAlarmSet(null /* inOrder */, "TIMEOUT",
                expectedWaitSecs, mDependencies.mDhcpClient.getHandler());
        mDependencies.mDhcpClient.getHandler().post(() -> alarm.onAlarm());
        // Implicitly check that the client never sent a DHCPREQUEST to request the offered address.
        verifyDhcpPacketRequestsIPv6OnlyPreferredOption(DhcpDiscoverPacket.class);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDiscoverIPv6OnlyPreferredOption() throws Exception {
        doDiscoverIPv6OnlyPreferredOptionTest(TEST_IPV6_ONLY_WAIT_S, TEST_IPV6_ONLY_WAIT_S);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDiscoverIPv6OnlyPreferredOption_LowerIPv6OnlyWait() throws Exception {
        doDiscoverIPv6OnlyPreferredOptionTest(TEST_LOWER_IPV6_ONLY_WAIT_S,
                TEST_LOWER_IPV6_ONLY_WAIT_S);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDiscoverIPv6OnlyPreferredOption_ZeroIPv6OnlyWait() throws Exception {
        doDiscoverIPv6OnlyPreferredOptionTest(TEST_ZERO_IPV6_ONLY_WAIT_S,
                TEST_LOWER_IPV6_ONLY_WAIT_S);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDiscoverIPv6OnlyPreferredOption_MaxIPv6OnlyWait() throws Exception {
        doDiscoverIPv6OnlyPreferredOptionTest((int) TEST_MAX_IPV6_ONLY_WAIT_S, 0xffffffffL);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDiscoverIPv6OnlyPreferredOption_ZeroIPv6OnlyWaitWithOfferedAnyAddress()
            throws Exception {
        doIPv6OnlyPreferredOptionTest(TEST_ZERO_IPV6_ONLY_WAIT_S, IPV4_ADDR_ANY);

        final OnAlarmListener alarm = expectAlarmSet(null /* inOrder */, "TIMEOUT", 300,
                mDependencies.mDhcpClient.getHandler());
        mDependencies.mDhcpClient.getHandler().post(() -> alarm.onAlarm());

        verifyDhcpPacketRequestsIPv6OnlyPreferredOption(DhcpDiscoverPacket.class);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDiscoverIPv6OnlyPreferredOption_enabledPreconnection() throws Exception {
        final ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIpReachabilityMonitor()
                .withPreconnection()
                .build();

        setDhcpFeatures(false /* isDhcpLeaseCacheEnabled */, true /* isRapidCommitEnabled */,
                false /* isDhcpIpConflictDetectEnabled */, true /* isIPv6OnlyPreferredEnabled */);
        startIpClientProvisioning(config);

        final DhcpPacket packet = assertDiscoverPacketOnPreconnectionStart();
        verify(mCb).setNeighborDiscoveryOffload(true);

        // Force IpClient transition to RunningState from PreconnectionState.
        mIpc.notifyPreconnectionComplete(true /* success */);
        HandlerUtils.waitForIdle(mDependencies.mDhcpClient.getHandler(), TEST_TIMEOUT_MS);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).setFallbackMulticastFilter(true);

        // DHCP server SHOULD NOT honor the Rapid-Commit option if the response would
        // contain the IPv6-only Preferred option to the client, instead respond with
        // a DHCPOFFER.
        mPacketReader.sendResponse(buildDhcpOfferPacket(packet, CLIENT_ADDR, TEST_LEASE_DURATION_S,
                (short) TEST_DEFAULT_MTU, null /* captivePortalUrl */, TEST_IPV6_ONLY_WAIT_S));

        final OnAlarmListener alarm = expectAlarmSet(null /* inOrder */, "TIMEOUT", 1800,
                mDependencies.mDhcpClient.getHandler());
        mDependencies.mDhcpClient.getHandler().post(() -> alarm.onAlarm());

        verifyDhcpPacketRequestsIPv6OnlyPreferredOption(DhcpDiscoverPacket.class);
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testDiscoverIPv6OnlyPreferredOption_NoIPv6OnlyPreferredOption() throws Exception {
        doIPv6OnlyPreferredOptionTest(null /* ipv6OnlyWaitTime */, CLIENT_ADDR);

        // The IPv6-only Preferred option SHOULD be included in the Parameter Request List option
        // in DHCPREQUEST messages after receiving a DHCPOFFER without this option.
        verifyDhcpPacketRequestsIPv6OnlyPreferredOption(DhcpRequestPacket.class);
    }

    private void setUpRetrievedNetworkAttributesForInitRebootState() {
        final NetworkAttributes na = new NetworkAttributes.Builder()
                .setAssignedV4Address(CLIENT_ADDR)
                .setAssignedV4AddressExpiry(Long.MAX_VALUE) // lease is always valid
                .setMtu(new Integer(TEST_DEFAULT_MTU))
                .setCluster(TEST_CLUSTER)
                .setDnsAddresses(Collections.singletonList(SERVER_ADDR))
                .build();
        storeNetworkAttributes(TEST_L2KEY, na);
    }

    private void startFromInitRebootStateWithIPv6OnlyPreferredOption(final Integer ipv6OnlyWaitTime,
            final long expectedWaitSecs) throws Exception {
        setUpRetrievedNetworkAttributesForInitRebootState();

        final ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIpReachabilityMonitor()
                .withLayer2Information(new Layer2Information(TEST_L2KEY, TEST_CLUSTER,
                          MacAddress.fromString(TEST_DEFAULT_BSSID)))
                .build();

        setDhcpFeatures(true /* isDhcpLeaseCacheEnabled */, false /* isRapidCommitEnabled */,
                false /* isDhcpIpConflictDetectEnabled */, true /* isIPv6OnlyPreferredEnabled */);
        startIpClientProvisioning(config);

        final DhcpPacket packet =
                verifyDhcpPacketRequestsIPv6OnlyPreferredOption(DhcpRequestPacket.class);

        // Respond DHCPACK with IPv6-Only preferred option.
        mPacketReader.sendResponse(buildDhcpAckPacket(packet, CLIENT_ADDR,
                TEST_LEASE_DURATION_S, (short) TEST_DEFAULT_MTU, false /* rapidcommit */,
                null /* captivePortalUrl */, ipv6OnlyWaitTime));

        if (ipv6OnlyWaitTime != null) {
            expectAlarmSet(null /* inOrder */, "TIMEOUT", expectedWaitSecs,
                    mDependencies.mDhcpClient.getHandler());
        }
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testRequestIPv6OnlyPreferredOption() throws Exception {
        startFromInitRebootStateWithIPv6OnlyPreferredOption(TEST_IPV6_ONLY_WAIT_S,
                TEST_IPV6_ONLY_WAIT_S);

        // Client transits to IPv6OnlyPreferredState from INIT-REBOOT state when receiving valid
        // IPv6-Only preferred option(default value) in the DHCPACK packet.
        assertIpMemoryNeverStoreNetworkAttributes();
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testRequestIPv6OnlyPreferredOption_LowerIPv6OnlyWait() throws Exception {
        startFromInitRebootStateWithIPv6OnlyPreferredOption(TEST_LOWER_IPV6_ONLY_WAIT_S,
                TEST_LOWER_IPV6_ONLY_WAIT_S);

        // Client transits to IPv6OnlyPreferredState from INIT-REBOOT state when receiving valid
        // IPv6-Only preferred option(less than MIN_V6ONLY_WAIT_MS) in the DHCPACK packet.
        assertIpMemoryNeverStoreNetworkAttributes();
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testRequestIPv6OnlyPreferredOption_ZeroIPv6OnlyWait() throws Exception {
        startFromInitRebootStateWithIPv6OnlyPreferredOption(TEST_ZERO_IPV6_ONLY_WAIT_S,
                TEST_LOWER_IPV6_ONLY_WAIT_S);

        // Client transits to IPv6OnlyPreferredState from INIT-REBOOT state when receiving valid
        // IPv6-Only preferred option(0) in the DHCPACK packet.
        assertIpMemoryNeverStoreNetworkAttributes();
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testRequestIPv6OnlyPreferredOption_MaxIPv6OnlyWait() throws Exception {
        startFromInitRebootStateWithIPv6OnlyPreferredOption((int) TEST_MAX_IPV6_ONLY_WAIT_S,
                0xffffffffL);

        // Client transits to IPv6OnlyPreferredState from INIT-REBOOT state when receiving valid
        // IPv6-Only preferred option(MAX_UNSIGNED_INTEGER: 0xFFFFFFFF) in the DHCPACK packet.
        assertIpMemoryNeverStoreNetworkAttributes();
    }

    @Test @SignatureRequiredTest(reason = "TODO: evaluate whether signature perms are required")
    public void testRequestIPv6OnlyPreferredOption_NoIPv6OnlyPreferredOption() throws Exception {
        final long currentTime = System.currentTimeMillis();
        startFromInitRebootStateWithIPv6OnlyPreferredOption(null /* ipv6OnlyWaitTime */,
                0 /* expectedWaitSecs */);

        // Client processes DHCPACK packet normally and transits to the ConfiguringInterfaceState
        // due to the null V6ONLY_WAIT.
        assertIpMemoryStoreNetworkAttributes(TEST_LEASE_DURATION_S, currentTime, TEST_DEFAULT_MTU);
    }

    private static int getNumOpenFds() {
        return new File("/proc/" + Os.getpid() + "/fd").listFiles().length;
    }

    private void shutdownAndRecreateIpClient() throws Exception {
        clearInvocations(mCb);
        mIpc.shutdown();
        awaitIpClientShutdown();
        mIpc = makeIpClient();
    }

    @Test @SignatureRequiredTest(reason = "Only counts FDs from the current process. TODO: fix")
    public void testNoFdLeaks() throws Exception {
        // Shut down and restart IpClient once to ensure that any fds that are opened the first
        // time it runs do not cause the test to fail.
        doDualStackProvisioning();
        shutdownAndRecreateIpClient();

        // Unfortunately we cannot use a large number of iterations as it would make the test run
        // too slowly. On crosshatch-eng each iteration takes ~250ms.
        final int iterations = 10;
        final int before = getNumOpenFds();
        for (int i = 0; i < iterations; i++) {
            doDualStackProvisioning();
            shutdownAndRecreateIpClient();
            // The last time this loop runs, mIpc will be shut down in tearDown.
        }
        final int after = getNumOpenFds();

        // Check that the number of open fds is the same as before, within some tolerance (e.g.,
        // garbage collection or other cleanups might have caused an fd to be closed). This
        // shouldn't make leak detection much less reliable, since it's likely that any leak would
        // at least leak one FD per loop.
        final int tolerance = 4;
        assertTrue(
                "FD leak detected after " + iterations + " iterations: expected "
                        + before + " +/- " + tolerance + " fds, found " + after,
                Math.abs(after - before) <= tolerance);
    }

    // TODO: delete when DhcpOption is @JavaOnlyImmutable.
    private static DhcpOption makeDhcpOption(final byte type, final byte[] value) {
        final DhcpOption opt = new DhcpOption();
        opt.type = type;
        opt.value = value;
        return opt;
    }

    private static final List<DhcpOption> TEST_OEM_DHCP_OPTIONS = Arrays.asList(
            // DHCP_USER_CLASS
            makeDhcpOption((byte) 77, TEST_OEM_USER_CLASS_INFO),
            // DHCP_VENDOR_CLASS_ID
            makeDhcpOption((byte) 60, TEST_OEM_VENDOR_ID.getBytes())
    );

    private DhcpPacket doCustomizedDhcpOptionsTest(final List<DhcpOption> options,
             final ScanResultInfo info, boolean isDhcpLeaseCacheEnabled) throws Exception {
        ProvisioningConfiguration.Builder prov = new ProvisioningConfiguration.Builder()
                .withoutIpReachabilityMonitor()
                .withLayer2Information(new Layer2Information(TEST_L2KEY, TEST_CLUSTER,
                        MacAddress.fromString(TEST_DEFAULT_BSSID)))
                .withScanResultInfo(info)
                .withDhcpOptions(options)
                .withoutIPv6();

        setDhcpFeatures(isDhcpLeaseCacheEnabled, false /* isRapidCommitEnabled */,
                false /* isDhcpIpConflictDetectEnabled */, false /* isIPv6OnlyPreferredEnabled */);

        startIpClientProvisioning(prov.build());
        verify(mCb, timeout(TEST_TIMEOUT_MS)).setFallbackMulticastFilter(true);
        verify(mCb, never()).onProvisioningFailure(any());

        return getNextDhcpPacket();
    }

    @Test
    public void testDiscoverCustomizedDhcpOptions() throws Exception {
        final ScanResultInfo info = makeScanResultInfo(0xdd /* vendor-specific IE */, TEST_OEM_OUI,
                (byte) 0x11 /* vendor-specific IE type */);
        final DhcpPacket packet = doCustomizedDhcpOptionsTest(TEST_OEM_DHCP_OPTIONS, info,
                false /* isDhcpLeaseCacheEnabled */);

        assertTrue(packet instanceof DhcpDiscoverPacket);
        assertEquals(packet.mVendorId, TEST_OEM_VENDOR_ID);
        assertArrayEquals(packet.mUserClass, TEST_OEM_USER_CLASS_INFO);
    }

    @Test
    public void testDiscoverCustomizedDhcpOptions_nullDhcpOptions() throws Exception {
        final ScanResultInfo info = makeScanResultInfo(0xdd /* vendor-specific IE */, TEST_OEM_OUI,
                (byte) 0x11 /* vendor-specific IE type */);
        final DhcpPacket packet = doCustomizedDhcpOptionsTest(null /* options */, info,
                false /* isDhcpLeaseCacheEnabled */);

        assertTrue(packet instanceof DhcpDiscoverPacket);
        assertEquals(packet.mVendorId, new String("android-dhcp-" + Build.VERSION.RELEASE));
        assertNull(packet.mUserClass);
    }

    @Test
    public void testDiscoverCustomizedDhcpOptions_nullScanResultInfo() throws Exception {
        final DhcpPacket packet = doCustomizedDhcpOptionsTest(TEST_OEM_DHCP_OPTIONS,
                null /* scanResultInfo */, false /* isDhcpLeaseCacheEnabled */);

        assertTrue(packet instanceof DhcpDiscoverPacket);
        assertEquals(packet.mVendorId, new String("android-dhcp-" + Build.VERSION.RELEASE));
        assertNull(packet.mUserClass);
    }

    @Test
    public void testDiscoverCustomizedDhcpOptions_disallowedOui() throws Exception {
        final ScanResultInfo info = makeScanResultInfo(0xdd /* vendor-specific IE */,
                new byte[]{ 0x00, 0x11, 0x22} /* oui */, (byte) 0x11 /* vendor-specific IE type */);
        final DhcpPacket packet = doCustomizedDhcpOptionsTest(TEST_OEM_DHCP_OPTIONS, info,
                false /* isDhcpLeaseCacheEnabled */);

        assertTrue(packet instanceof DhcpDiscoverPacket);
        assertEquals(packet.mVendorId, new String("android-dhcp-" + Build.VERSION.RELEASE));
        assertNull(packet.mUserClass);
    }

    @Test
    public void testDiscoverCustomizedDhcpOptions_invalidIeId() throws Exception {
        final ScanResultInfo info = makeScanResultInfo(0xde /* vendor-specific IE */, TEST_OEM_OUI,
                (byte) 0x11 /* vendor-specific IE type */);
        final DhcpPacket packet = doCustomizedDhcpOptionsTest(TEST_OEM_DHCP_OPTIONS, info,
                false /* isDhcpLeaseCacheEnabled */);

        assertTrue(packet instanceof DhcpDiscoverPacket);
        assertEquals(packet.mVendorId, new String("android-dhcp-" + Build.VERSION.RELEASE));
        assertNull(packet.mUserClass);
    }

    @Test
    public void testDiscoverCustomizedDhcpOptions_invalidVendorSpecificType() throws Exception {
        final ScanResultInfo info = makeScanResultInfo(0xdd /* vendor-specific IE */, TEST_OEM_OUI,
                (byte) 0x10 /* vendor-specific IE type */);
        final DhcpPacket packet = doCustomizedDhcpOptionsTest(TEST_OEM_DHCP_OPTIONS, info,
                false /* isDhcpLeaseCacheEnabled */);

        assertTrue(packet instanceof DhcpDiscoverPacket);
        assertEquals(packet.mVendorId, new String("android-dhcp-" + Build.VERSION.RELEASE));
        assertNull(packet.mUserClass);
    }

    @Test
    public void testDisoverCustomizedDhcpOptions_disallowedOption() throws Exception {
        final List<DhcpOption> options = Arrays.asList(
                makeDhcpOption((byte) 60, TEST_OEM_VENDOR_ID.getBytes()),
                makeDhcpOption((byte) 77, TEST_OEM_USER_CLASS_INFO),
                // Option 26: MTU
                makeDhcpOption((byte) 26, HexDump.toByteArray(TEST_DEFAULT_MTU)));
        final ScanResultInfo info = makeScanResultInfo(0xdd /* vendor-specific IE */, TEST_OEM_OUI,
                (byte) 0x11 /* vendor-specific IE type */);
        final DhcpPacket packet = doCustomizedDhcpOptionsTest(options, info,
                false /* isDhcpLeaseCacheEnabled */);

        assertTrue(packet instanceof DhcpDiscoverPacket);
        assertEquals(packet.mVendorId, TEST_OEM_VENDOR_ID);
        assertArrayEquals(packet.mUserClass, TEST_OEM_USER_CLASS_INFO);
        assertNull(packet.mMtu);
    }

    @Test
    public void testDiscoverCustomizedDhcpOptions_disallowedParamRequestOption() throws Exception {
        final List<DhcpOption> options = Arrays.asList(
                makeDhcpOption((byte) 60, TEST_OEM_VENDOR_ID.getBytes()),
                makeDhcpOption((byte) 77, TEST_OEM_USER_CLASS_INFO),
                // NTP_SERVER
                makeDhcpOption((byte) 42, null));
        final ScanResultInfo info = makeScanResultInfo(0xdd /* vendor-specific IE */, TEST_OEM_OUI,
                (byte) 0x11 /* vendor-specific IE type */);
        final DhcpPacket packet = doCustomizedDhcpOptionsTest(options, info,
                false /* isDhcpLeaseCacheEnabled */);

        assertTrue(packet instanceof DhcpDiscoverPacket);
        assertEquals(packet.mVendorId, TEST_OEM_VENDOR_ID);
        assertArrayEquals(packet.mUserClass, TEST_OEM_USER_CLASS_INFO);
        assertFalse(packet.hasRequestedParam((byte) 42 /* NTP_SERVER */));
    }

    @Test
    public void testDiscoverCustomizedDhcpOptions_ParameterRequestListOnly() throws Exception {
        final List<DhcpOption> options = Arrays.asList(
                // DHCP_USER_CLASS
                makeDhcpOption((byte) 77, null));
        final ScanResultInfo info = makeScanResultInfo(0xdd /* vendor-specific IE */, TEST_OEM_OUI,
                (byte) 0x11 /* vendor-specific IE type */);
        final DhcpPacket packet = doCustomizedDhcpOptionsTest(options, info,
                false /* isDhcpLeaseCacheEnabled */);

        assertTrue(packet instanceof DhcpDiscoverPacket);
        assertTrue(packet.hasRequestedParam((byte) 77 /* DHCP_USER_CLASS */));
        assertNull(packet.mUserClass);
    }

    @Test
    public void testRequestCustomizedDhcpOptions() throws Exception {
        setUpRetrievedNetworkAttributesForInitRebootState();

        final ScanResultInfo info = makeScanResultInfo(0xdd /* vendor-specific IE */, TEST_OEM_OUI,
                (byte) 0x11 /* vendor-specific IE type */);
        final DhcpPacket packet = doCustomizedDhcpOptionsTest(TEST_OEM_DHCP_OPTIONS, info,
                true /* isDhcpLeaseCacheEnabled */);

        assertTrue(packet instanceof DhcpRequestPacket);
        assertEquals(packet.mVendorId, TEST_OEM_VENDOR_ID);
        assertArrayEquals(packet.mUserClass, TEST_OEM_USER_CLASS_INFO);
    }

    @Test
    public void testRequestCustomizedDhcpOptions_nullDhcpOptions() throws Exception {
        setUpRetrievedNetworkAttributesForInitRebootState();

        final ScanResultInfo info = makeScanResultInfo(0xdd /* vendor-specific IE */, TEST_OEM_OUI,
                (byte) 0x11 /* vendor-specific IE type */);
        final DhcpPacket packet = doCustomizedDhcpOptionsTest(null /* options */, info,
                true /* isDhcpLeaseCacheEnabled */);

        assertTrue(packet instanceof DhcpRequestPacket);
        assertEquals(packet.mVendorId, new String("android-dhcp-" + Build.VERSION.RELEASE));
        assertNull(packet.mUserClass);
    }

    @Test
    public void testRequestCustomizedDhcpOptions_nullScanResultInfo() throws Exception {
        setUpRetrievedNetworkAttributesForInitRebootState();

        final DhcpPacket packet = doCustomizedDhcpOptionsTest(TEST_OEM_DHCP_OPTIONS,
                null /* scanResultInfo */, true /* isDhcpLeaseCacheEnabled */);

        assertTrue(packet instanceof DhcpRequestPacket);
        assertEquals(packet.mVendorId, new String("android-dhcp-" + Build.VERSION.RELEASE));
        assertNull(packet.mUserClass);
    }

    @Test
    public void testRequestCustomizedDhcpOptions_disallowedOui() throws Exception {
        setUpRetrievedNetworkAttributesForInitRebootState();

        final ScanResultInfo info = makeScanResultInfo(0xdd /* vendor-specific IE */,
                new byte[]{ 0x00, 0x11, 0x22} /* oui */, (byte) 0x11 /* vendor-specific IE type */);
        final DhcpPacket packet = doCustomizedDhcpOptionsTest(TEST_OEM_DHCP_OPTIONS, info,
                true /* isDhcpLeaseCacheEnabled */);

        assertTrue(packet instanceof DhcpRequestPacket);
        assertEquals(packet.mVendorId, new String("android-dhcp-" + Build.VERSION.RELEASE));
        assertNull(packet.mUserClass);
    }

    @Test
    public void testRequestCustomizedDhcpOptions_invalidIeId() throws Exception {
        setUpRetrievedNetworkAttributesForInitRebootState();

        final ScanResultInfo info = makeScanResultInfo(0xde /* vendor-specific IE */, TEST_OEM_OUI,
                (byte) 0x11 /* vendor-specific IE type */);
        final DhcpPacket packet = doCustomizedDhcpOptionsTest(TEST_OEM_DHCP_OPTIONS, info,
                true /* isDhcpLeaseCacheEnabled */);

        assertTrue(packet instanceof DhcpRequestPacket);
        assertEquals(packet.mVendorId, new String("android-dhcp-" + Build.VERSION.RELEASE));
        assertNull(packet.mUserClass);
    }

    @Test
    public void testRequestCustomizedDhcpOptions_invalidVendorSpecificType() throws Exception {
        setUpRetrievedNetworkAttributesForInitRebootState();

        final ScanResultInfo info = makeScanResultInfo(0xdd /* vendor-specific IE */, TEST_OEM_OUI,
                (byte) 0x10 /* vendor-specific IE type */);
        final DhcpPacket packet = doCustomizedDhcpOptionsTest(TEST_OEM_DHCP_OPTIONS, info,
                true /* isDhcpLeaseCacheEnabled */);

        assertTrue(packet instanceof DhcpRequestPacket);
        assertEquals(packet.mVendorId, new String("android-dhcp-" + Build.VERSION.RELEASE));
        assertNull(packet.mUserClass);
    }

    @Test
    public void testRequestCustomizedDhcpOptions_disallowedOption() throws Exception {
        setUpRetrievedNetworkAttributesForInitRebootState();

        final List<DhcpOption> options = Arrays.asList(
                makeDhcpOption((byte) 60, TEST_OEM_VENDOR_ID.getBytes()),
                makeDhcpOption((byte) 77, TEST_OEM_USER_CLASS_INFO),
                // Option 26: MTU
                makeDhcpOption((byte) 26, HexDump.toByteArray(TEST_DEFAULT_MTU)));
        final ScanResultInfo info = makeScanResultInfo(0xdd /* vendor-specific IE */, TEST_OEM_OUI,
                (byte) 0x11 /* vendor-specific IE type */);
        final DhcpPacket packet = doCustomizedDhcpOptionsTest(options, info,
                true /* isDhcpLeaseCacheEnabled */);

        assertTrue(packet instanceof DhcpRequestPacket);
        assertEquals(packet.mVendorId, TEST_OEM_VENDOR_ID);
        assertArrayEquals(packet.mUserClass, TEST_OEM_USER_CLASS_INFO);
        assertNull(packet.mMtu);
    }

    @Test
    public void testRequestCustomizedDhcpOptions_disallowedParamRequestOption() throws Exception {
        setUpRetrievedNetworkAttributesForInitRebootState();

        final List<DhcpOption> options = Arrays.asList(
                makeDhcpOption((byte) 60, TEST_OEM_VENDOR_ID.getBytes()),
                makeDhcpOption((byte) 77, TEST_OEM_USER_CLASS_INFO),
                // NTP_SERVER
                makeDhcpOption((byte) 42, null));
        final ScanResultInfo info = makeScanResultInfo(0xdd /* vendor-specific IE */, TEST_OEM_OUI,
                (byte) 0x11 /* vendor-specific IE type */);
        final DhcpPacket packet = doCustomizedDhcpOptionsTest(options, info,
                true /* isDhcpLeaseCacheEnabled */);

        assertTrue(packet instanceof DhcpRequestPacket);
        assertEquals(packet.mVendorId, TEST_OEM_VENDOR_ID);
        assertArrayEquals(packet.mUserClass, TEST_OEM_USER_CLASS_INFO);
        assertFalse(packet.hasRequestedParam((byte) 42 /* NTP_SERVER */));
    }

    @Test
    public void testRequestCustomizedDhcpOptions_ParameterRequestListOnly() throws Exception {
        setUpRetrievedNetworkAttributesForInitRebootState();

        final List<DhcpOption> options = Arrays.asList(
                // DHCP_USER_CLASS
                makeDhcpOption((byte) 77, null));
        final ScanResultInfo info = makeScanResultInfo(0xdd /* vendor-specific IE */, TEST_OEM_OUI,
                (byte) 0x11 /* vendor-specific IE type */);
        final DhcpPacket packet = doCustomizedDhcpOptionsTest(options, info,
                true /* isDhcpLeaseCacheEnabled */);

        assertTrue(packet instanceof DhcpRequestPacket);
        assertTrue(packet.hasRequestedParam((byte) 77 /* DHCP_USER_CLASS */));
        assertNull(packet.mUserClass);
    }

    private void assertGratuitousNa(final NeighborAdvertisement na) throws Exception {
        final MacAddress etherMulticast =
                NetworkStackUtils.ipv6MulticastToEthernetMulticast(IPV6_ADDR_ALL_ROUTERS_MULTICAST);
        final LinkAddress target = new LinkAddress(na.naHdr.target, 64);

        assertEquals(etherMulticast, na.ethHdr.dstMac);
        assertEquals(ETH_P_IPV6, na.ethHdr.etherType);
        assertEquals(IPPROTO_ICMPV6, na.ipv6Hdr.nextHeader);
        assertEquals(0xff, na.ipv6Hdr.hopLimit);
        assertTrue(na.ipv6Hdr.srcIp.isLinkLocalAddress());
        assertEquals(IPV6_ADDR_ALL_ROUTERS_MULTICAST, na.ipv6Hdr.dstIp);
        assertEquals(ICMPV6_NEIGHBOR_ADVERTISEMENT, na.icmpv6Hdr.type);
        assertEquals(0, na.icmpv6Hdr.code);
        assertEquals(0, na.naHdr.flags);
        assertTrue(target.isGlobalPreferred());
    }

    private void assertMulticastNsFromIpv6Gua(final NeighborSolicitation ns) throws Exception {
        final Inet6Address solicitedNodeMulticast =
                NetworkStackUtils.ipv6AddressToSolicitedNodeMulticast(ROUTER_LINK_LOCAL);
        final MacAddress etherMulticast =
                NetworkStackUtils.ipv6MulticastToEthernetMulticast(solicitedNodeMulticast);

        assertEquals(etherMulticast, ns.ethHdr.dstMac);
        assertEquals(ETH_P_IPV6, ns.ethHdr.etherType);
        assertEquals(IPPROTO_ICMPV6, ns.ipv6Hdr.nextHeader);
        assertEquals(0xff, ns.ipv6Hdr.hopLimit);

        final LinkAddress srcIp = new LinkAddress(ns.ipv6Hdr.srcIp.getHostAddress() + "/64");
        assertTrue(srcIp.isGlobalPreferred());
        assertEquals(solicitedNodeMulticast, ns.ipv6Hdr.dstIp);
        assertEquals(ICMPV6_NEIGHBOR_SOLICITATION, ns.icmpv6Hdr.type);
        assertEquals(0, ns.icmpv6Hdr.code);
        assertEquals(ROUTER_LINK_LOCAL, ns.nsHdr.target);
    }

    @Test
    public void testGratuitousNaForNewGlobalUnicastAddresses() throws Exception {
        final ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIpReachabilityMonitor()
                .withoutIPv4()
                .build();

        setFeatureEnabled(NetworkStackUtils.IPCLIENT_GRATUITOUS_NA_VERSION,
                true /* isGratuitousNaEnabled */);
        assertTrue(isFeatureEnabled(NetworkStackUtils.IPCLIENT_GRATUITOUS_NA_VERSION, false));
        startIpClientProvisioning(config);

        doIpv6OnlyProvisioning();

        final List<NeighborAdvertisement> naList = new ArrayList<>();
        NeighborAdvertisement packet;
        while ((packet = getNextNeighborAdvertisement()) != null) {
            assertGratuitousNa(packet);
            naList.add(packet);
        }
        assertEquals(2, naList.size()); // privacy address and stable privacy address
    }

    private void startGratuitousArpAndNaAfterRoamingTest(boolean isGratuitousArpNaRoamingEnabled,
            boolean hasIpv4, boolean hasIpv6) throws Exception {
        final Layer2Information layer2Info = new Layer2Information(TEST_L2KEY, TEST_CLUSTER,
                MacAddress.fromString(TEST_DEFAULT_BSSID));
        final ScanResultInfo scanResultInfo =
                makeScanResultInfo(TEST_DEFAULT_SSID, TEST_DEFAULT_BSSID);
        final ProvisioningConfiguration.Builder prov = new ProvisioningConfiguration.Builder()
                .withoutIpReachabilityMonitor()
                .withLayer2Information(layer2Info)
                .withScanResultInfo(scanResultInfo)
                .withDisplayName("ssid");
        if (!hasIpv4) prov.withoutIPv4();
        if (!hasIpv6) prov.withoutIPv6();

        // Enable rapid commit to accelerate DHCP handshake to shorten test duration,
        // not strictly necessary.
        setDhcpFeatures(false /* isDhcpLeaseCacheEnabled */, true /* isRapidCommitEnabled */,
                false /* isDhcpIpConflictDetectEnabled */, false /* isIPv6OnlyPreferredEnabled */);
        if (isGratuitousArpNaRoamingEnabled) {
            setFeatureEnabled(NetworkStackUtils.IPCLIENT_GARP_NA_ROAMING_VERSION, true);
            assertTrue(isFeatureEnabled(NetworkStackUtils.IPCLIENT_GARP_NA_ROAMING_VERSION, false));
        }
        startIpClientProvisioning(prov.build());
    }

    private void waitForGratuitousArpAndNaPacket(final List<ArpPacket> arpList,
            final List<NeighborAdvertisement> naList) throws Exception {
        NeighborAdvertisement na;
        ArpPacket garp;
        do {
            na = getNextNeighborAdvertisement();
            if (na != null) {
                assertGratuitousNa(na);
                naList.add(na);
            }
            garp = getNextArpPacket(TEST_TIMEOUT_MS);
            if (garp != null) {
                assertGratuitousARP(garp);
                arpList.add(garp);
            }
        } while (na != null || garp != null);
    }

    @Test
    public void testGratuitousArpAndNaAfterRoaming() throws Exception {
        startGratuitousArpAndNaAfterRoamingTest(true /* isGratuitousArpNaRoamingEnabled */,
                true /* hasIpv4 */, true /* hasIpv6 */);
        performDualStackProvisioning();
        forceLayer2Roaming();

        final List<ArpPacket> arpList = new ArrayList<>();
        final List<NeighborAdvertisement> naList = new ArrayList<>();
        waitForGratuitousArpAndNaPacket(arpList, naList);
        assertEquals(2, naList.size()); // privacy address and stable privacy address
        assertEquals(1, arpList.size()); // IPv4 address
    }

    @Test
    public void testGratuitousArpAndNaAfterRoaming_disableExpFlag() throws Exception {
        startGratuitousArpAndNaAfterRoamingTest(false /* isGratuitousArpNaRoamingEnabled */,
                true /* hasIpv4 */, true /* hasIpv6 */);
        performDualStackProvisioning();
        forceLayer2Roaming();

        final List<ArpPacket> arpList = new ArrayList<>();
        final List<NeighborAdvertisement> naList = new ArrayList<>();
        waitForGratuitousArpAndNaPacket(arpList, naList);
        assertEquals(0, naList.size());
        assertEquals(0, arpList.size());
    }

    @Test
    public void testGratuitousArpAndNaAfterRoaming_IPv6OnlyNetwork() throws Exception {
        startGratuitousArpAndNaAfterRoamingTest(true /* isGratuitousArpNaRoamingEnabled */,
                false /* hasIpv4 */, true /* hasIpv6 */);
        doIpv6OnlyProvisioning();
        forceLayer2Roaming();

        final List<ArpPacket> arpList = new ArrayList<>();
        final List<NeighborAdvertisement> naList = new ArrayList<>();
        waitForGratuitousArpAndNaPacket(arpList, naList);
        assertEquals(2, naList.size());
        assertEquals(0, arpList.size());
    }

    @Test
    public void testGratuitousArpAndNaAfterRoaming_IPv4OnlyNetwork() throws Exception {
        startGratuitousArpAndNaAfterRoamingTest(true /* isGratuitousArpNaRoamingEnabled */,
                true /* hasIpv4 */, false /* hasIpv6 */);

        // Start IPv4 provisioning and wait until entire provisioning completes.
        handleDhcpPackets(true /* isSuccessLease */, TEST_LEASE_DURATION_S,
                true /* shouldReplyRapidCommitAck */, TEST_DEFAULT_MTU, null /* serverSentUrl */);
        verifyIPv4OnlyProvisioningSuccess(Collections.singletonList(CLIENT_ADDR));
        forceLayer2Roaming();

        final List<ArpPacket> arpList = new ArrayList<>();
        final List<NeighborAdvertisement> naList = new ArrayList<>();
        waitForGratuitousArpAndNaPacket(arpList, naList);
        assertEquals(0, naList.size());
        assertEquals(1, arpList.size());
    }

    private void assertNeighborSolicitation(final NeighborSolicitation ns,
            final Inet6Address target) {
        assertEquals(ETH_P_IPV6, ns.ethHdr.etherType);
        assertEquals(IPPROTO_ICMPV6, ns.ipv6Hdr.nextHeader);
        assertEquals(0xff, ns.ipv6Hdr.hopLimit);
        assertTrue(ns.ipv6Hdr.srcIp.isLinkLocalAddress());
        assertEquals(ICMPV6_NEIGHBOR_SOLICITATION, ns.icmpv6Hdr.type);
        assertEquals(0, ns.icmpv6Hdr.code);
        assertEquals(0, ns.nsHdr.reserved);
        assertEquals(target, ns.nsHdr.target);
        assertEquals(ns.slla.linkLayerAddress, ns.ethHdr.srcMac);
    }

    private void assertUnicastNeighborSolicitation(final NeighborSolicitation ns,
            final MacAddress dstMac, final Inet6Address dstIp, final Inet6Address target) {
        assertEquals(dstMac, ns.ethHdr.dstMac);
        assertEquals(dstIp, ns.ipv6Hdr.dstIp);
        assertNeighborSolicitation(ns, target);
    }

    private void assertMulticastNeighborSolicitation(final NeighborSolicitation ns,
            final Inet6Address target) {
        final MacAddress etherMulticast =
                NetworkStackUtils.ipv6MulticastToEthernetMulticast(ns.ipv6Hdr.dstIp);
        assertEquals(etherMulticast, ns.ethHdr.dstMac);
        assertTrue(ns.ipv6Hdr.dstIp.isMulticastAddress());
        assertNeighborSolicitation(ns, target);
    }

    private NeighborSolicitation waitForUnicastNeighborSolicitation(final MacAddress dstMac,
            final Inet6Address dstIp, final Inet6Address targetIp) throws Exception {
        NeighborSolicitation ns;
        while ((ns = getNextNeighborSolicitation()) != null) {
            // Filter out the multicast NSes used for duplicate address detetction, the target
            // address is the global IPv6 address inside these NSes, and multicast NSes sent from
            // device's GUAs to force first-hop router to update the neighbor cache entry.
            if (ns.ipv6Hdr.srcIp.isLinkLocalAddress() && ns.nsHdr.target.isLinkLocalAddress()) {
                break;
            }
        }
        assertNotNull("No unicast Neighbor solicitation received on interface within timeout", ns);
        assertUnicastNeighborSolicitation(ns, dstMac, dstIp, targetIp);
        return ns;
    }

    private List<NeighborSolicitation> waitForMultipleNeighborSolicitations() throws Exception {
        NeighborSolicitation ns;
        final List<NeighborSolicitation> nsList = new ArrayList<NeighborSolicitation>();
        while ((ns = getNextNeighborSolicitation()) != null) {
            // Filter out the multicast NSes used for duplicate address detetction, the target
            // address is the global IPv6 address inside these NSes, and multicast NSes sent from
            // device's GUAs to force first-hop router to update the neighbor cache entry.
            if (ns.ipv6Hdr.srcIp.isLinkLocalAddress() && ns.nsHdr.target.isLinkLocalAddress()) {
                nsList.add(ns);
            }
        }
        assertFalse(nsList.isEmpty());
        return nsList;
    }

    private NeighborSolicitation expectDadNeighborSolicitationForLinkLocal(boolean shouldDisableDad)
            throws Exception {
        final NeighborSolicitation ns = getNextNeighborSolicitation();
        if (!shouldDisableDad) {
            final Inet6Address solicitedNodeMulticast =
                    NetworkStackUtils.ipv6AddressToSolicitedNodeMulticast(ns.nsHdr.target);
            assertNotNull("No multicast NS received on interface within timeout", ns);
            assertEquals(IPV6_ADDR_ANY, ns.ipv6Hdr.srcIp);     // srcIp: ::/
            assertTrue(ns.ipv6Hdr.dstIp.isMulticastAddress()); // dstIp: solicited-node mcast
            assertTrue(ns.ipv6Hdr.dstIp.equals(solicitedNodeMulticast));
            assertTrue(ns.nsHdr.target.isLinkLocalAddress());  // targetIp: IPv6 LL address
        } else {
            assertNull(ns);
        }
        return ns;
    }

    // Override this function with disabled experiment flag by default, in order not to
    // affect those tests which are just related to basic IpReachabilityMonitor infra.
    private void prepareIpReachabilityMonitorTest() throws Exception {
        prepareIpReachabilityMonitorTest(false /* isMulticastResolicitEnabled */);
    }

    private void assertNotifyNeighborLost(Inet6Address targetIp, NudEventType eventType)
            throws Exception {
        // For root test suite, rely on the IIpClient aidl interface version constant defined in
        // {@link IpClientRootTest.BinderCbWrapper}; for privileged integration test suite that
        // requires signature permission, use the mocked aidl version defined in {@link setUpMocks},
        // which results in only new callbacks are verified. And add separate test cases to test the
        // legacy callbacks explicitly as well.
        assertNeighborReachabilityLoss(targetIp, eventType,
                useNetworkStackSignature()
                        ? IpClient.VERSION_ADDED_REACHABILITY_FAILURE
                        : mIIpClient.getInterfaceVersion());
    }

    private void assertNeighborReachabilityLoss(Inet6Address targetIp, NudEventType eventType,
            int targetAidlVersion) throws Exception {
        if (targetAidlVersion >= IpClient.VERSION_ADDED_REACHABILITY_FAILURE) {
            final ArgumentCaptor<ReachabilityLossInfoParcelable> lossInfoCaptor =
                    ArgumentCaptor.forClass(ReachabilityLossInfoParcelable.class);
            verify(mCb, timeout(TEST_TIMEOUT_MS)).onReachabilityFailure(lossInfoCaptor.capture());
            assertEquals(nudEventTypeToInt(eventType), lossInfoCaptor.getValue().reason);
            verify(mCb, never()).onReachabilityLost(any());
        } else {
            verify(mCb, timeout(TEST_TIMEOUT_MS)).onReachabilityLost(any());
            verify(mCb, never()).onReachabilityFailure(any());
        }
    }

    private void assertNeverNotifyNeighborLost() throws Exception {
        verify(mCb, never()).onReachabilityFailure(any());
        verify(mCb, never()).onReachabilityLost(any());
    }

    private void prepareIpReachabilityMonitorTest(boolean isMulticastResolicitEnabled)
            throws Exception {
        final ScanResultInfo info = makeScanResultInfo(TEST_DEFAULT_SSID, TEST_DEFAULT_BSSID);
        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withLayer2Information(new Layer2Information(TEST_L2KEY, TEST_CLUSTER,
                       MacAddress.fromString(TEST_DEFAULT_BSSID)))
                .withScanResultInfo(info)
                .withDisplayName(TEST_DEFAULT_SSID)
                .withoutIPv4()
                .build();
        setFeatureEnabled(NetworkStackUtils.IP_REACHABILITY_MCAST_RESOLICIT_VERSION,
                isMulticastResolicitEnabled);
        startIpClientProvisioning(config);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).setFallbackMulticastFilter(true);
        doIpv6OnlyProvisioning();

        // Simulate the roaming.
        forceLayer2Roaming();
    }

    private void runIpReachabilityMonitorProbeFailedTest() throws Exception {
        prepareIpReachabilityMonitorTest();

        final List<NeighborSolicitation> nsList = waitForMultipleNeighborSolicitations();
        final int expectedNudSolicitNum = readNudSolicitNumPostRoamingFromResource();
        assertEquals(expectedNudSolicitNum, nsList.size());
        for (NeighborSolicitation ns : nsList) {
            assertUnicastNeighborSolicitation(ns, ROUTER_MAC /* dstMac */,
                    ROUTER_LINK_LOCAL /* dstIp */, ROUTER_LINK_LOCAL /* targetIp */);
        }
    }

    @Test
    public void testIpReachabilityMonitor_probeFailed() throws Exception {
        runIpReachabilityMonitorProbeFailedTest();
        assertNotifyNeighborLost(ROUTER_LINK_LOCAL /* targetIp */,
                NudEventType.NUD_POST_ROAMING_FAILED_CRITICAL);
    }

    @Test @SignatureRequiredTest(reason = "requires mock callback object")
    public void testIpReachabilityMonitor_probeFailed_legacyCallback() throws Exception {
        when(mCb.getInterfaceVersion()).thenReturn(12 /* assign an older interface aidl version */);

        runIpReachabilityMonitorProbeFailedTest();
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onReachabilityLost(any());
        verify(mCb, never()).onReachabilityFailure(any());
    }

    @Test
    public void testIpReachabilityMonitor_probeReachable() throws Exception {
        prepareIpReachabilityMonitorTest();

        final NeighborSolicitation ns = waitForUnicastNeighborSolicitation(ROUTER_MAC /* dstMac */,
                ROUTER_LINK_LOCAL /* dstIp */, ROUTER_LINK_LOCAL /* targetIp */);

        // Reply Neighbor Advertisement and check notifyLost callback won't be triggered.
        int flag = NEIGHBOR_ADVERTISEMENT_FLAG_ROUTER | NEIGHBOR_ADVERTISEMENT_FLAG_SOLICITED;
        final ByteBuffer na = NeighborAdvertisement.build(ROUTER_MAC /* srcMac */,
                ns.ethHdr.srcMac /* dstMac */, ROUTER_LINK_LOCAL /* srcIp */,
                ns.ipv6Hdr.srcIp /* dstIp */, flag, ROUTER_LINK_LOCAL /* target */);
        mPacketReader.sendResponse(na);
        assertNeverNotifyNeighborLost();
    }

    private void runIpReachabilityMonitorMcastResolicitProbeFailedTest() throws Exception {
        prepareIpReachabilityMonitorTest(true /* isMulticastResolicitEnabled */);

        final List<NeighborSolicitation> nsList = waitForMultipleNeighborSolicitations();
        final int expectedNudSolicitNum = readNudSolicitNumPostRoamingFromResource();
        int expectedSize = expectedNudSolicitNum + NUD_MCAST_RESOLICIT_NUM;
        assertEquals(expectedSize, nsList.size());
        for (NeighborSolicitation ns : nsList.subList(0, expectedNudSolicitNum)) {
            assertUnicastNeighborSolicitation(ns, ROUTER_MAC /* dstMac */,
                    ROUTER_LINK_LOCAL /* dstIp */, ROUTER_LINK_LOCAL /* targetIp */);
        }
        for (NeighborSolicitation ns : nsList.subList(expectedNudSolicitNum, nsList.size())) {
            assertMulticastNeighborSolicitation(ns, ROUTER_LINK_LOCAL /* targetIp */);
        }
    }

    @Test
    public void testIpReachabilityMonitor_mcastResolicitProbeFailed() throws Exception {
        runIpReachabilityMonitorMcastResolicitProbeFailedTest();
        assertNotifyNeighborLost(ROUTER_LINK_LOCAL /* targetIp */,
                NudEventType.NUD_POST_ROAMING_FAILED_CRITICAL);
    }

    @Test @SignatureRequiredTest(reason = "requires mock callback object")
    public void testIpReachabilityMonitor_mcastResolicitProbeFailed_legacyCallback()
            throws Exception {
        when(mCb.getInterfaceVersion()).thenReturn(12 /* assign an older interface aidl version */);

        runIpReachabilityMonitorMcastResolicitProbeFailedTest();
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onReachabilityLost(any());
        verify(mCb, never()).onReachabilityFailure(any());
    }

    @Test
    public void testIpReachabilityMonitor_mcastResolicitProbeReachableWithSameLinkLayerAddress()
            throws Exception {
        prepareIpReachabilityMonitorTest(true /* isMulticastResolicitEnabled */);

        final NeighborSolicitation ns = waitForUnicastNeighborSolicitation(ROUTER_MAC /* dstMac */,
                ROUTER_LINK_LOCAL /* dstIp */, ROUTER_LINK_LOCAL /* targetIp */);

        // Reply Neighbor Advertisement and check notifyLost callback won't be triggered.
        int flag = NEIGHBOR_ADVERTISEMENT_FLAG_ROUTER | NEIGHBOR_ADVERTISEMENT_FLAG_SOLICITED;
        final ByteBuffer na = NeighborAdvertisement.build(ROUTER_MAC /* srcMac */,
                ns.ethHdr.srcMac /* dstMac */, ROUTER_LINK_LOCAL /* srcIp */,
                ns.ipv6Hdr.srcIp /* dstIp */, flag, ROUTER_LINK_LOCAL /* target */);
        mPacketReader.sendResponse(na);
        assertNeverNotifyNeighborLost();
    }

    @Test
    public void testIpReachabilityMonitor_mcastResolicitProbeReachableWithDiffLinkLayerAddress()
            throws Exception {
        prepareIpReachabilityMonitorTest(true /* isMulticastResolicitEnabled */);

        final NeighborSolicitation ns = waitForUnicastNeighborSolicitation(ROUTER_MAC /* dstMac */,
                ROUTER_LINK_LOCAL /* dstIp */, ROUTER_LINK_LOCAL /* targetIp */);

        // Reply Neighbor Advertisement with a different link-layer address and check notifyLost
        // callback will be triggered. Override flag must be set, which indicates that the
        // advertisement should override an existing cache entry and update the cached link-layer
        // address, otherwise, kernel won't transit to REACHABLE state with a different link-layer
        // address.
        int flag = NEIGHBOR_ADVERTISEMENT_FLAG_ROUTER | NEIGHBOR_ADVERTISEMENT_FLAG_SOLICITED
                | NEIGHBOR_ADVERTISEMENT_FLAG_OVERRIDE;
        final MacAddress newMac = MacAddress.fromString("00:1a:11:22:33:55");
        final ByteBuffer na = NeighborAdvertisement.build(newMac /* srcMac */,
                ns.ethHdr.srcMac /* dstMac */, ROUTER_LINK_LOCAL /* srcIp */,
                ns.ipv6Hdr.srcIp /* dstIp */, flag, ROUTER_LINK_LOCAL /* target */);
        mPacketReader.sendResponse(na);
        assertNotifyNeighborLost(ROUTER_LINK_LOCAL /* targetIp */,
                NudEventType.NUD_POST_ROAMING_MAC_ADDRESS_CHANGED);
    }

    private void sendUdpPacketToNetwork(final Network network, final Inet6Address remoteIp,
            int port, final byte[] data) throws Exception {
        final DatagramSocket socket = new DatagramSocket(0, (InetAddress) Inet6Address.ANY);
        final DatagramPacket pkt = new DatagramPacket(data, data.length, remoteIp, port);
        network.bindSocket(socket);
        socket.send(pkt);
    }

    private void runIpReachabilityMonitorAddressResolutionTest(final String dnsServer,
            final Inet6Address targetIp,
            final boolean isIgnoreIncompleteIpv6DnsServerEnabled,
            final boolean isIgnoreIncompleteIpv6DefaultRouterEnabled,
            final boolean expectNeighborLost) throws Exception {
        mNetworkAgentThread =
                new HandlerThread(IpClientIntegrationTestCommon.class.getSimpleName());
        mNetworkAgentThread.start();

        setDhcpFeatures(false /* isDhcpLeaseCacheEnabled */, true /* isRapidCommitEnabled */,
                false /* isDhcpIpConflictDetectEnabled */,
                false /* isIPv6OnlyPreferredEnabled */);
        setFeatureEnabled(
                NetworkStackUtils.IP_REACHABILITY_IGNORE_INCOMPLETE_IPV6_DNS_SERVER_VERSION,
                isIgnoreIncompleteIpv6DnsServerEnabled);
        setFeatureEnabled(
                NetworkStackUtils.IP_REACHABILITY_IGNORE_INCOMPLETE_IPV6_DEFAULT_ROUTER_VERSION,
                isIgnoreIncompleteIpv6DefaultRouterEnabled);
        final ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .build();
        startIpClientProvisioning(config);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).setFallbackMulticastFilter(true);

        final List<ByteBuffer> options = new ArrayList<ByteBuffer>();
        options.add(buildPioOption(3600, 1800, "2001:db8:1::/64")); // PIO
        options.add(buildRdnssOption(3600, dnsServer));             // RDNSS
        // If target IP of address resolution is default router's IPv6 link-local address,
        // then we should not take SLLA option in RA.
        if (!targetIp.equals(ROUTER_LINK_LOCAL)) {
            options.add(buildSllaOption());                         // SLLA
        }
        final ByteBuffer ra = buildRaPacket(options.toArray(new ByteBuffer[options.size()]));
        final Inet6Address dnsServerIp =
                (Inet6Address) InetAddresses.parseNumericAddress(dnsServer);
        final LinkProperties lp = performDualStackProvisioning(ra, dnsServerIp);
        runAsShell(MANAGE_TEST_NETWORKS, () -> createTestNetworkAgentAndRegister(lp));

        // Send a UDP packet to IPv6 DNS server to trigger address resolution process for IPv6
        // on-link DNS server or default router(if the target is default router, we should pass
        // in an IPv6 off-link DNS server such as 2001:db8:4860:4860::64).
        final Random random = new Random();
        final byte[] data = new byte[100];
        random.nextBytes(data);
        sendUdpPacketToNetwork(mNetworkAgent.getNetwork(), dnsServerIp, 1234 /* port */, data);

        // Wait for the multicast NSes but never respond to them, that results in the on-link
        // DNS gets lost and onReachabilityLost callback will be invoked.
        final List<NeighborSolicitation> nsList = new ArrayList<NeighborSolicitation>();
        NeighborSolicitation ns;
        while ((ns = getNextNeighborSolicitation()) != null) {
            // multicast NS for address resolution, IPv6 dst address in that NS is solicited-node
            // multicast address based on the target IP, the target IP is either on-link IPv6 DNS
            // server address or IPv6 link-local address of default gateway.
            final LinkAddress actual = new LinkAddress(ns.nsHdr.target, 64);
            final LinkAddress target = new LinkAddress(targetIp, 64);
            if (actual.equals(target) && ns.ipv6Hdr.dstIp.isMulticastAddress()) {
                nsList.add(ns);
            }
        }
        assertFalse(nsList.isEmpty());

        if (expectNeighborLost) {
            assertNotifyNeighborLost(targetIp, NudEventType.NUD_ORGANIC_FAILED_CRITICAL);
        } else {
            assertNeverNotifyNeighborLost();
        }
    }

    @Test
    @SignatureRequiredTest(reason = "Need to mock NetworkAgent")
    public void testIpReachabilityMonitor_incompleteIpv6DnsServerInDualStack() throws Exception {
        final Inet6Address targetIp =
                (Inet6Address) InetAddresses.parseNumericAddress(IPV6_ON_LINK_DNS_SERVER);
        runIpReachabilityMonitorAddressResolutionTest(IPV6_ON_LINK_DNS_SERVER, targetIp,
                true /* isIgnoreIncompleteIpv6DnsServerEnabled */,
                false /* isIgnoreIncompleteIpv6DefaultRouterEnabled */,
                false /* expectNeighborLost */);
    }

    @Test
    @SignatureRequiredTest(reason = "Need to mock NetworkAgent")
    public void testIpReachabilityMonitor_incompleteIpv6DnsServerInDualStack_flagoff()
            throws Exception {
        final Inet6Address targetIp =
                (Inet6Address) InetAddresses.parseNumericAddress(IPV6_ON_LINK_DNS_SERVER);
        runIpReachabilityMonitorAddressResolutionTest(IPV6_ON_LINK_DNS_SERVER, targetIp,
                false /* isIgnoreIncompleteIpv6DnsServerEnabled */,
                false /* isIgnoreIncompleteIpv6DefaultRouterEnabled */,
                true /* expectNeighborLost */);
    }

    @Test
    @SignatureRequiredTest(reason = "Need to mock the NetworkAgent")
    public void testIpReachabilityMonitor_incompleteIpv6DefaultRouterInDualStack()
            throws Exception {
        runIpReachabilityMonitorAddressResolutionTest(IPV6_OFF_LINK_DNS_SERVER,
                ROUTER_LINK_LOCAL /* targetIp */,
                false /* isIgnoreIncompleteIpv6DnsServerEnabled */,
                true /* isIgnoreIncompleteIpv6DefaultRouterEnabled */,
                false /* expectNeighborLost */);
    }

    @Test
    @SignatureRequiredTest(reason = "Need to mock the NetworkAgent")
    public void testIpReachabilityMonitor_incompleteIpv6DefaultRouterInDualStack_flagoff()
            throws Exception {
        runIpReachabilityMonitorAddressResolutionTest(IPV6_OFF_LINK_DNS_SERVER,
                ROUTER_LINK_LOCAL /* targetIp */,
                false /* isIgnoreIncompleteIpv6DnsServerEnabled */,
                false /* isIgnoreIncompleteIpv6DefaultRouterEnabled */,
                true /* expectNeighborLost */);
    }

    @Test
    public void testIPv6LinkLocalOnly() throws Exception {
        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIPv4()
                .withIpv6LinkLocalOnly()
                .withRandomMacAddress()
                .build();
        startIpClientProvisioning(config);

        final ArgumentCaptor<LinkProperties> captor = ArgumentCaptor.forClass(LinkProperties.class);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningSuccess(captor.capture());
        final LinkProperties lp = captor.getValue();
        assertNotNull(lp);
        assertEquals(0, lp.getDnsServers().size());
        final List<LinkAddress> addresses = lp.getLinkAddresses();
        assertEquals(1, addresses.size());
        assertTrue(addresses.get(0).getAddress().isLinkLocalAddress()); // only IPv6 link-local
        assertTrue(hasRouteTo(lp, IPV6_LINK_LOCAL_PREFIX)); // fe80::/64 -> :: iface mtu 0

        // Check that if an RA is received, no IP addresses, routes, or DNS servers are configured.
        // Instead of waiting some period of time for the RA to be received and checking the
        // LinkProperties after that, tear down the interface and wait for it to go down. Then check
        // that no LinkProperties updates ever contained non-link-local information.
        sendBasicRouterAdvertisement(false /* waitForRs */);
        teardownTapInterface();
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningFailure(any());
        verify(mCb, never()).onLinkPropertiesChange(argThat(newLp ->
                // Ideally there should be only one route(fe80::/64 -> :: iface mtu 0) in the
                // LinkProperties, however, the multicast route(ff00::/8 -> :: iface mtu 0) may
                // appear on some old platforms where the kernel is still notifying the userspace
                // the multicast route. Therefore, we cannot assert that size of routes in the
                // LinkProperties is more than one, but other properties such as DNS or IPv6
                // default route or global IPv6 address should never appear in the IPv6 link-local
                // only mode.
                newLp.getDnsServers().size() != 0
                        || newLp.hasIpv6DefaultRoute()
                        || newLp.hasGlobalIpv6Address()
        ));
    }

    @Test
    public void testIPv6LinkLocalOnly_verifyAcceptRaDefrtr() throws Exception {
        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIPv4()
                .withIpv6LinkLocalOnly()
                .withRandomMacAddress()
                .build();
        startIpClientProvisioning(config);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningSuccess(any());

        clearInvocations(mCb);

        // accept_ra is set to 0 and accept_ra_defrtr is set to 1 in IPv6 link-local only mode,
        // send another RA to tap interface, to verify that we should not see any IPv6 provisioning
        // although accept_ra_defrtr is set to 1.
        sendBasicRouterAdvertisement(false /* waitForRs */);
        verify(mCb, never()).onLinkPropertiesChange(argThat(x -> x.isIpv6Provisioned()));
    }

    @Test
    public void testIPv6LinkLocalOnlyAndThenGlobal() throws Exception {
        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIPv4()
                .withIpv6LinkLocalOnly()
                .withRandomMacAddress()
                .build();
        startIpClientProvisioning(config);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningSuccess(any());
        mIIpClient.stop();
        verifyAfterIpClientShutdown();
        reset(mCb);

        // Speed up provisioning by enabling rapid commit. TODO: why is this necessary?
        setDhcpFeatures(false /* isDhcpLeaseCacheEnabled */, true /* isRapidCommitEnabled */,
                false /* isDhcpIpConflictDetectEnabled */, false /* isIPv6OnlyPreferredEnabled */);
        config = new ProvisioningConfiguration.Builder()
                .build();
        startIpClientProvisioning(config);
        performDualStackProvisioning();
        // No exceptions? Dual-stack provisioning worked.
    }

    @Test
    public void testIPv6LinkLocalOnly_enableBothIPv4andIPv6LinkLocalOnly() throws Exception {
        assertThrows(IllegalArgumentException.class,
                () -> new ProvisioningConfiguration.Builder()
                        .withoutIpReachabilityMonitor()
                        .withIpv6LinkLocalOnly()
                        .withRandomMacAddress()
                        .build()
        );
    }

    private void runIpv6LinkLocalOnlyDadTransmitsCheckTest(boolean shouldDisableDad)
            throws Exception {
        ProvisioningConfiguration.Builder config = new ProvisioningConfiguration.Builder()
                .withoutIPv4()
                .withIpv6LinkLocalOnly()
                .withRandomMacAddress();
        if (shouldDisableDad) config.withUniqueEui64AddressesOnly();

        // dad_transmits has been set to 0 in disableIpv6ProvisioningDelays, re-enable dad_transmits
        // for testing, but production code could disable dad again later, we should never see any
        // multicast NS for duplicate address detection then.
        mNetd.setProcSysNet(INetd.IPV6, INetd.CONF, mIfaceName, "dad_transmits", "1");
        startIpClientProvisioning(config.build());
        verify(mNetd, timeout(TEST_TIMEOUT_MS)).interfaceSetEnableIPv6(mIfaceName, true);
        // Check dad_transmits should be set to 0 if UniqueEui64AddressesOnly mode is enabled.
        int dadTransmits = Integer.parseUnsignedInt(
                mNetd.getProcSysNet(INetd.IPV6, INetd.CONF, mIfaceName, "dad_transmits"));
        if (shouldDisableDad) {
            assertEquals(0, dadTransmits);
        } else {
            assertEquals(1, dadTransmits);
        }

        final NeighborSolicitation ns =
                expectDadNeighborSolicitationForLinkLocal(shouldDisableDad);
        if (shouldDisableDad) {
            assertNull(ns);
        } else {
            assertNotNull(ns);
        }

        // Shutdown IpClient and check if the dad_transmits always equals to default value 1 (if
        // dad_transmit was set to 0 before, it should get recovered to default value 1 after
        // shutting down IpClient)
        mIpc.shutdown();
        awaitIpClientShutdown();
        dadTransmits = Integer.parseUnsignedInt(
                mNetd.getProcSysNet(INetd.IPV6, INetd.CONF, mIfaceName, "dad_transmits"));
        assertEquals(1, dadTransmits);
    }

    @Test
    @SignatureRequiredTest(reason = "requires mocked netd")
    public void testIPv6LinkLocalOnly_enableDad() throws Exception {
        runIpv6LinkLocalOnlyDadTransmitsCheckTest(false /* shouldDisableDad */);
    }

    @Test
    @SignatureRequiredTest(reason = "requires mocked netd")
    public void testIPv6LinkLocalOnly_disableDad() throws Exception {
        runIpv6LinkLocalOnlyDadTransmitsCheckTest(true /* shouldDisableDad */);
    }

    // Since createTapInterface(boolean, String) method was introduced since T, this method
    // cannot be found on Q/R/S platform, ignore this test on T- platform.
    @Test
    @IgnoreUpTo(Build.VERSION_CODES.S_V2)
    public void testIpClientLinkObserver_onClatInterfaceStateUpdate() throws Exception {
        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIPv4()
                .build();
        startIpClientProvisioning(config);
        doIpv6OnlyProvisioning();

        reset(mCb);

        // Add the clat interface and check the callback.
        final TestNetworkInterface clatIface = setUpClatInterface(mIfaceName);
        assertNotNull(clatIface);
        assertTrue(clatIface.getInterfaceName().equals(CLAT_PREFIX + mIfaceName));
        verify(mCb, timeout(TEST_TIMEOUT_MS)).setNeighborDiscoveryOffload(false);

        // Remove the clat interface and check the callback.
        removeTestInterface(clatIface.getFileDescriptor().getFileDescriptor());
        verify(mCb, timeout(TEST_TIMEOUT_MS)).setNeighborDiscoveryOffload(true);
    }

    @Test @SignatureRequiredTest(reason = "requires mock callback object")
    public void testNetlinkSocketReceiveENOBUFS() throws Exception {
        // Only run the test when the flag of parsing netlink events is enabled.
        assumeTrue(mIsNetlinkEventParseEnabled);

        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIPv4()
                .build();
        startIpClientProvisioning(config);
        doIpv6OnlyProvisioning();
        HandlerUtils.waitForIdle(mIpc.getHandler(), TEST_TIMEOUT_MS);

        final Handler handler = mIpc.getHandler();
        // Block IpClient handler.
        final CountDownLatch latch = new CountDownLatch(1);
        handler.post(() -> {
            try {
                latch.await(10, TimeUnit.SECONDS);
            } catch (InterruptedException e) {
                fail("latch wait unexpectedly interrupted");
            }
        });

        // Send large amount of RAs to overflow the netlink socket receive buffer.
        for (int i = 0; i < 200; i++) {
            sendBasicRouterAdvertisement(false /* waitRs */);
        }

        // Send another RA with a different IPv6 global prefix. This PIO option should be dropped
        // due to the ENOBUFS happens, it means IpClient shouldn't see the new IPv6 global prefix.
        final String prefix = "2001:db8:dead:beef::/64";
        final ByteBuffer pio = buildPioOption(3600, 1800, prefix);
        ByteBuffer rdnss = buildRdnssOption(3600, IPV6_OFF_LINK_DNS_SERVER);
        sendRouterAdvertisement(false /* waitForRs */, (short) 1800, pio, rdnss);

        // Unblock the IpClient handler and ENOBUFS should happen then.
        latch.countDown();
        HandlerUtils.waitForIdle(handler, TEST_WAIT_ENOBUFS_TIMEOUT_MS);

        reset(mCb);

        // Send RA with 0 router lifetime to see if IpClient can see the loss of IPv6 default route.
        // Due to ignoring the ENOBUFS and wait until handler gets idle, IpClient should be still
        // able to see the RA with 0 router lifetime and the IPv6 default route will be removed.
        // LinkProperties should not include any route to the new prefix 2001:db8:dead:beef::/64.
        sendRouterAdvertisementWithZeroRouterLifetime();
        final ArgumentCaptor<LinkProperties> captor = ArgumentCaptor.forClass(LinkProperties.class);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningFailure(captor.capture());
        final LinkProperties lp = captor.getValue();
        assertNotNull(lp);
        assertFalse(hasRouteTo(lp, prefix));
        assertFalse(lp.hasIpv6DefaultRoute());
    }

    @Test
    public void testMulticastNsFromIPv6Gua() throws Exception {
        final ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIpReachabilityMonitor()
                .withoutIPv4()
                .build();

        setFeatureEnabled(NetworkStackUtils.IPCLIENT_MULTICAST_NS_VERSION,
                true /* isUnsolicitedNsEnabled */);
        assertTrue(isFeatureEnabled(NetworkStackUtils.IPCLIENT_MULTICAST_NS_VERSION, false));
        startIpClientProvisioning(config);

        doIpv6OnlyProvisioning();

        final List<NeighborSolicitation> nsList = new ArrayList<>();
        NeighborSolicitation packet;
        while ((packet = getNextNeighborSolicitation()) != null) {
            // Filter out the NSes used for duplicate address detetction, whose target address
            // is the global IPv6 address inside these NSes.
            if (packet.nsHdr.target.isLinkLocalAddress()) {
                assertMulticastNsFromIpv6Gua(packet);
                nsList.add(packet);
            }
        }
        assertEquals(2, nsList.size()); // from privacy address and stable privacy address
    }

    @Test
    public void testDeprecatedGlobalUnicastAddress() throws Exception {
        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIPv4()
                .build();
        startIpClientProvisioning(config);
        doIpv6OnlyProvisioning();

        // Send RA with PIO(0 preferred but valid lifetime) to deprecate the global IPv6 addresses.
        // Check all of global IPv6 addresses will become deprecated, but still valid.
        // NetworkStackUtils#isIPv6GUA() will return false for deprecated addresses, however, when
        // checking if the DNS is still reachable, deprecated addresses are not acceptable, that
        // results in the on-link DNS server gets lost from LinkProperties, and provisioning failure
        // happened.
        // TODO: update the logic of checking reachable on-link DNS server to accept the deprecated
        // addresses, then onProvisioningFailure callback should never happen.
        sendRouterAdvertisement(false /* waitForRs*/, (short) 1800 /* router lifetime */,
                3600 /* valid */, 0 /* preferred */);
        final ArgumentCaptor<LinkProperties> captor = ArgumentCaptor.forClass(LinkProperties.class);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningFailure(captor.capture());
        final LinkProperties lp = captor.getValue();
        assertNotNull(lp);
        assertFalse(lp.hasGlobalIpv6Address());
        assertEquals(3, lp.getLinkAddresses().size()); // IPv6 privacy, stable privacy, link-local
        for (LinkAddress la : lp.getLinkAddresses()) {
            assertFalse(NetworkStackUtils.isIPv6GUA(la));
        }
    }

    @Test @SignatureRequiredTest(reason = "requires mNetd to delete IPv6 GUAs")
    public void testOnIpv6AddressRemoved() throws Exception {
        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIPv4()
                .build();
        startIpClientProvisioning(config);

        LinkProperties lp = doIpv6OnlyProvisioning();
        assertNotNull(lp);
        assertEquals(3, lp.getLinkAddresses().size()); // IPv6 privacy, stable privacy, link-local
        for (LinkAddress la : lp.getLinkAddresses()) {
            final Inet6Address address = (Inet6Address) la.getAddress();
            if (address.isLinkLocalAddress()) continue;
            // Remove IPv6 GUAs from interface.
            mNetd.interfaceDelAddress(mIfaceName, address.getHostAddress(), la.getPrefixLength());
        }

        final ArgumentCaptor<LinkProperties> captor = ArgumentCaptor.forClass(LinkProperties.class);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningFailure(captor.capture());
        lp = captor.getValue();
        assertFalse(lp.hasGlobalIpv6Address());
        assertEquals(1, lp.getLinkAddresses().size()); // only link-local
    }

    @Test
    public void testMaxDtimMultiplier_IPv6OnlyNetwork() throws Exception {
        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIPv4()
                .build();
        startIpClientProvisioning(config);

        verify(mCb, timeout(TEST_TIMEOUT_MS)).setMaxDtimMultiplier(
                IpClient.DEFAULT_BEFORE_IPV6_PROV_MAX_DTIM_MULTIPLIER);

        LinkProperties lp = doIpv6OnlyProvisioning();
        assertNotNull(lp);
        assertEquals(3, lp.getLinkAddresses().size()); // IPv6 privacy, stable privacy, link-local
        verify(mCb, timeout(TEST_TIMEOUT_MS)).setMaxDtimMultiplier(
                IpClient.DEFAULT_IPV6_ONLY_NETWORK_MAX_DTIM_MULTIPLIER);
    }

    @Test
    public void testMaxDtimMultiplier_IPv6LinkLocalOnlyMode() throws Exception {
        final InOrder inOrder = inOrder(mCb);
        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIPv4()
                .withIpv6LinkLocalOnly()
                .build();
        startIpClientProvisioning(config);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningSuccess(any());
        // IPv6 DTIM grace period doesn't apply to IPv6 link-local only mode and the multiplier
        // has been initialized to DTIM_MULTIPLIER_RESET before starting provisioning, therefore,
        // the multiplier should not be updated neither.
        verify(mCb, never()).setMaxDtimMultiplier(
                IpClient.DEFAULT_BEFORE_IPV6_PROV_MAX_DTIM_MULTIPLIER);
        verify(mCb, never()).setMaxDtimMultiplier(DTIM_MULTIPLIER_RESET);
    }

    @Test
    public void testMaxDtimMultiplier_IPv4OnlyNetwork() throws Exception {
        performDhcpHandshake(true /* isSuccessLease */, TEST_LEASE_DURATION_S,
                true /* isDhcpLeaseCacheEnabled */, false /* shouldReplyRapidCommitAck */,
                TEST_DEFAULT_MTU, false /* isDhcpIpConflictDetectEnabled */);
        verifyIPv4OnlyProvisioningSuccess(Collections.singletonList(CLIENT_ADDR));
        verify(mCb, timeout(TEST_TIMEOUT_MS).times(1)).setMaxDtimMultiplier(
                IpClient.DEFAULT_IPV4_ONLY_NETWORK_MAX_DTIM_MULTIPLIER);
        // IPv6 DTIM grace period doesn't apply to IPv4-only networks.
        verify(mCb, never()).setMaxDtimMultiplier(
                IpClient.DEFAULT_BEFORE_IPV6_PROV_MAX_DTIM_MULTIPLIER);
    }

    private void runDualStackNetworkDtimMultiplierSetting(final InOrder inOrder) throws Exception {
        doDualStackProvisioning();
        inOrder.verify(mCb).setMaxDtimMultiplier(
                IpClient.DEFAULT_BEFORE_IPV6_PROV_MAX_DTIM_MULTIPLIER);
        inOrder.verify(mCb, timeout(TEST_TIMEOUT_MS)).setMaxDtimMultiplier(
                IpClient.DEFAULT_DUAL_STACK_MAX_DTIM_MULTIPLIER);
    }

    @Test
    public void testMaxDtimMultiplier_DualStackNetwork() throws Exception {
        final InOrder inOrder = inOrder(mCb);
        runDualStackNetworkDtimMultiplierSetting(inOrder);
    }

    @Test
    public void testMaxDtimMultiplier_MulticastLock() throws Exception {
        final InOrder inOrder = inOrder(mCb);
        runDualStackNetworkDtimMultiplierSetting(inOrder);

        // Simulate to hold the multicast lock by disabling the multicast filter.
        mIIpClient.setMulticastFilter(false);
        inOrder.verify(mCb, timeout(TEST_TIMEOUT_MS)).setMaxDtimMultiplier(
                IpClient.DEFAULT_MULTICAST_LOCK_MAX_DTIM_MULTIPLIER);

        // Simulate to disable the multicast lock again, then check the multiplier should be
        // changed to 2 (dual-stack setting)
        mIIpClient.setMulticastFilter(true);
        inOrder.verify(mCb, timeout(TEST_TIMEOUT_MS)).setMaxDtimMultiplier(
                IpClient.DEFAULT_DUAL_STACK_MAX_DTIM_MULTIPLIER);
    }

    @Test
    public void testMaxDtimMultiplier_MulticastLockEnabled_StoppedState() throws Exception {
        // Simulate to hold the multicast lock by disabling the multicast filter at StoppedState,
        // verify no callback to be sent, start dual-stack provisioning and verify the multiplier
        // to be set to 1 (multicast lock setting) later.
        mIIpClient.setMulticastFilter(false);
        verify(mCb, after(10).never()).setMaxDtimMultiplier(
                IpClient.DEFAULT_MULTICAST_LOCK_MAX_DTIM_MULTIPLIER);

        doDualStackProvisioning();
        verify(mCb, times(1)).setMaxDtimMultiplier(
                IpClient.DEFAULT_MULTICAST_LOCK_MAX_DTIM_MULTIPLIER);
    }

    @Test
    public void testMaxDtimMultiplier_resetMultiplier() throws Exception {
        final InOrder inOrder = inOrder(mCb);
        runDualStackNetworkDtimMultiplierSetting(inOrder);

        verify(mCb, never()).setMaxDtimMultiplier(DTIM_MULTIPLIER_RESET);

        // Stop IpClient and verify if the multiplier has been reset.
        mIIpClient.stop();
        inOrder.verify(mCb, timeout(TEST_TIMEOUT_MS)).setMaxDtimMultiplier(DTIM_MULTIPLIER_RESET);
    }

    private void handleDhcp6Packets(final IpPrefix prefix, boolean shouldReplyRapidCommit)
            throws Exception {
        handleDhcp6Packets(prefix, 3600 /* t1 */, 4500 /* t2 */, 4500 /* preferred */,
                7200 /* valid */, shouldReplyRapidCommit);
    }

    private void handleDhcp6Packets(final IpPrefix prefix, int t1, int t2, int preferred, int valid,
            boolean shouldReplyRapidCommit) throws Exception {
        Dhcp6Packet packet;
        while ((packet = getNextDhcp6Packet()) != null) {
            final ByteBuffer iapd = Dhcp6Packet.buildIaPdOption(packet.getIaId(), t1, t2,
                    preferred, valid, prefix.getRawAddress(), (byte) prefix.getPrefixLength());
            if (packet instanceof Dhcp6SolicitPacket) {
                if (shouldReplyRapidCommit) {
                    mPacketReader.sendResponse(buildDhcp6Reply(packet, iapd.array(), mClientMac,
                            (Inet6Address) mClientIpAddress, true /* rapidCommit */));
                } else {
                    mPacketReader.sendResponse(buildDhcp6Advertise(packet, iapd.array(), mClientMac,
                            (Inet6Address) mClientIpAddress));
                }
            } else if (packet instanceof Dhcp6RequestPacket) {
                mPacketReader.sendResponse(buildDhcp6Reply(packet, iapd.array(), mClientMac,
                          (Inet6Address) mClientIpAddress, false /* rapidCommit */));
            } else {
                fail("invalid DHCPv6 Packet");
            }

            if ((packet instanceof Dhcp6RequestPacket) || shouldReplyRapidCommit) {
                return;
            }
        }
        fail("No DHCPv6 packet received on interface within timeout");
    }

    private void prepareDhcp6PdTest() throws Exception {
        final String dnsServer = "2001:4860:4860::64";
        final ByteBuffer rdnss = buildRdnssOption(3600, dnsServer);
        final ByteBuffer ra = buildRaPacket(rdnss);

        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIPv4()
                .build();
        startIpClientProvisioning(config);

        waitForRouterSolicitation();
        mPacketReader.sendResponse(ra);
    }

    @Test
    public void testDhcp6Pd() throws Exception {
        final IpPrefix prefix = new IpPrefix("2001:db8:1::/64");
        prepareDhcp6PdTest();
        handleDhcp6Packets(prefix, true /* shouldReplyRapidCommit */);
        final ArgumentCaptor<LinkProperties> captor = ArgumentCaptor.forClass(LinkProperties.class);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningSuccess(captor.capture());
        assertTrue(hasIpv6AddressPrefixedWith(captor.getValue(), prefix));
    }

    @Test
    public void testDhcp6Pd_disableRapidCommit() throws Exception {
        final IpPrefix prefix = new IpPrefix("2001:db8:1::/64");
        prepareDhcp6PdTest();
        handleDhcp6Packets(prefix, false /* shouldReplyRapidCommit */);
        final ArgumentCaptor<LinkProperties> captor = ArgumentCaptor.forClass(LinkProperties.class);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningSuccess(captor.capture());
        assertTrue(hasIpv6AddressPrefixedWith(captor.getValue(), prefix));
    }

    @Test
    public void testDhcp6Pd_longPrefixLength() throws Exception {
        prepareDhcp6PdTest();
        handleDhcp6Packets(new IpPrefix("2001:db8:1::/80"), true /* shouldReplyRapidCommit */);
        verify(mCb, never()).onProvisioningSuccess(any());
    }

    @Test
    public void testDhcp6Pd_shortPrefixLength() throws Exception {
        final IpPrefix prefix = new IpPrefix("2001:db8:1::/56");
        prepareDhcp6PdTest();
        handleDhcp6Packets(prefix, true /* shouldReplyRapidCommit */);
        final ArgumentCaptor<LinkProperties> captor = ArgumentCaptor.forClass(LinkProperties.class);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningSuccess(captor.capture());
        assertTrue(hasIpv6AddressPrefixedWith(captor.getValue(), prefix));
    }

    @Test
    public void testDhcp6Pd_T1GreaterThanT2() throws Exception {
        prepareDhcp6PdTest();
        handleDhcp6Packets(new IpPrefix("2001:db8:1::/80"), 4500 /* t1 */, 3600 /* t2 */,
                4500 /* preferred */, 7200 /* valid */, true /* shouldReplyRapidCommit */);
        verify(mCb, never()).onProvisioningSuccess(any());
    }

    @Test
    public void testDhcp6Pd_preferredLifetimeGreaterThanValidLifetime() throws Exception {
        prepareDhcp6PdTest();
        handleDhcp6Packets(new IpPrefix("2001:db8:1::/80"), 3600 /* t1 */, 4500 /* t2 */,
                7200 /* preferred */, 4500 /* valid */, true /* shouldReplyRapidCommit */);
        verify(mCb, never()).onProvisioningSuccess(any());
    }

    @Test
    public void testDhcp6Pd_preferredLifetimeLessThanT2() throws Exception {
        prepareDhcp6PdTest();
        handleDhcp6Packets(new IpPrefix("2001:db8:1::/80"), 3600 /* t1 */, 4500 /* t2 */,
                3600 /* preferred */, 4000 /* valid */, true /* shouldReplyRapidCommit */);
        verify(mCb, never()).onProvisioningSuccess(any());
    }

    private void runDhcp6PdNotStartInDualStackTest(final String prefix, final String dnsServer)
            throws Exception {
        final List<ByteBuffer> options = new ArrayList<>();
        if (prefix != null) {
            options.add(buildPioOption(3600, 1800, prefix));
        }
        if (dnsServer != null) {
            options.add(buildRdnssOption(3600, dnsServer));
        }
        options.add(buildSllaOption());
        final ByteBuffer ra = buildRaPacket(options.toArray(new ByteBuffer[options.size()]));

        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .build();
        setDhcpFeatures(false /* isDhcpLeaseCacheEnabled */, true /* isRapidCommitEnabled */,
                false /* isDhcpIpConflictDetectEnabled */, false /* isIPv6OnlyPreferredEnabled */);
        startIpClientProvisioning(config);

        waitForRouterSolicitation();
        mPacketReader.sendResponse(ra);

        // Start IPv4 provisioning and wait until entire provisioning completes.
        handleDhcpPackets(true /* isSuccessLease */, TEST_LEASE_DURATION_S,
                true /* shouldReplyRapidCommitAck */, TEST_DEFAULT_MTU, null /* serverSentUrl */);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningSuccess(any());
    }

    @Test
    public void testDhcp6Pd_notStartWithGlobalPio() throws Exception {
        runDhcp6PdNotStartInDualStackTest("2001:db8:1::/64" /* prefix */,
                "2001:4860:4860::64" /* dnsServer */);
        // Reply with a normal RA with global prefix and an off-link DNS for IPv6 provisioning,
        // DHCPv6 prefix delegation should not start.
        assertNull(getNextDhcp6Packet(PACKET_TIMEOUT_MS));
    }

    @Test
    public void testDhcp6Pd_notStartWithUlaPioAndDns() throws Exception {
        runDhcp6PdNotStartInDualStackTest("fd7c:9df8:7f39:dc89::/64" /* prefix */,
                "fd7c:9df8:7f39:dc89::1"  /* dnsServer */);
        // Reply with a normal RA even with ULA prefix and on-link ULA DNS for IPv6 provisioning,
        // DHCPv6 prefix delegation should not start.
        assertNull(getNextDhcp6Packet(PACKET_TIMEOUT_MS));
    }

    @Test
    public void testDhcp6Pd_notStartWithUlaPioAndOffLinkDns() throws Exception {
        runDhcp6PdNotStartInDualStackTest("fd7c:9df8:7f39:dc89::/64" /* prefix */,
                "2001:4860:4860::64"  /* dnsServer */);
        // Reply with a normal RA even with ULA prefix and off-link DNS for IPv6 provisioning,
        // DHCPv6 prefix delegation should not start.
        assertNull(getNextDhcp6Packet(PACKET_TIMEOUT_MS));
    }

    @Test
    public void testDhcp6Pd_startWithNoNonIpv6LinkLocalAddresses() throws Exception {
        runDhcp6PdNotStartInDualStackTest(null /* prefix */,
                "2001:4860:4860::64"  /* dnsServer */);
        // Reply with a normal RA with only RDNSS but no PIO for IPv6 provisioning,
        // DHCPv6 prefix delegation should start.
        final Dhcp6Packet packet = getNextDhcp6Packet(PACKET_TIMEOUT_MS);
        assertTrue(packet instanceof Dhcp6SolicitPacket);
    }

    @Test
    public void testDhcp6Pd_dualstack() throws Exception {
        final String dnsServer = "2001:4860:4860::64";
        final ByteBuffer rdnss = buildRdnssOption(3600, dnsServer);
        final ByteBuffer ra = buildRaPacket(rdnss);

        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .build();
        setDhcpFeatures(false /* isDhcpLeaseCacheEnabled */, true /* isRapidCommitEnabled */,
                false /* isDhcpIpConflictDetectEnabled */, false /* isIPv6OnlyPreferredEnabled */);
        startIpClientProvisioning(config);

        waitForRouterSolicitation();
        mPacketReader.sendResponse(ra);

        // Start IPv4 provisioning and wait until entire provisioning completes.
        handleDhcpPackets(true /* isSuccessLease */, TEST_LEASE_DURATION_S,
                true /* shouldReplyRapidCommitAck */, TEST_DEFAULT_MTU, null /* serverSentUrl */);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningSuccess(any());

        // Start DHCPv6 Prefix Delegation.
        final IpPrefix prefix = new IpPrefix("2001:db8:1::/64");
        handleDhcp6Packets(prefix, false /* shouldReplyRapidCommit */);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onLinkPropertiesChange(argThat(
                x -> x.isIpv6Provisioned()
                        && hasIpv6AddressPrefixedWith(x, prefix)
                        && hasRouteTo(x, "2001:db8:1::/64", RTN_UNREACHABLE)
                        // IPv4 address, IPv6 link-local, two global delegated IPv6 addresses
                        && x.getLinkAddresses().size() == 4
        ));
    }

    private void prepareDhcp6PdRenewTest() throws Exception {
        final IpPrefix prefix = new IpPrefix("2001:db8:1::/64");
        prepareDhcp6PdTest();
        handleDhcp6Packets(prefix, true /* shouldReplyRapidCommit */);
        final ArgumentCaptor<LinkProperties> captor = ArgumentCaptor.forClass(LinkProperties.class);
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningSuccess(captor.capture());
        assertTrue(hasIpv6AddressPrefixedWith(captor.getValue(), prefix));
    }

    @Test
    @SignatureRequiredTest(reason = "Need to mock the DHCP6 renew/rebind alarms")
    public void testDhcp6Pd_renewAndRebind() throws Exception {
        prepareDhcp6PdRenewTest();

        final InOrder inOrder = inOrder(mAlarm);
        final Handler handler = mDependencies.mDhcp6Client.getHandler();
        final OnAlarmListener renewAlarm = expectAlarmSet(inOrder, "RENEW", 3600, handler);
        final OnAlarmListener rebindAlarm = expectAlarmSet(inOrder, "REBIND", 4500, handler);

        handler.post(() -> renewAlarm.onAlarm());
        HandlerUtils.waitForIdle(handler, TEST_TIMEOUT_MS);

        Dhcp6Packet packet = getNextDhcp6Packet();
        assertTrue(packet instanceof Dhcp6RenewPacket);

        handler.post(() -> rebindAlarm.onAlarm());
        HandlerUtils.waitForIdle(handler, TEST_TIMEOUT_MS);

        packet = getNextDhcp6Packet();
        assertTrue(packet instanceof Dhcp6RebindPacket);
    }

    @SignatureRequiredTest(reason = "Need to mock the DHCP6 renew/rebind alarms")
    @SkipPresubmit(reason = "Out of SLO flakiness")
    @Test
    public void testDhcp6Pd_prefixMismatchOnRenew() throws Exception {
        prepareDhcp6PdRenewTest();

        final InOrder inOrder = inOrder(mAlarm);
        final Handler handler = mDependencies.mDhcp6Client.getHandler();
        final OnAlarmListener renewAlarm = expectAlarmSet(inOrder, "RENEW", 3600, handler);

        handler.post(() -> renewAlarm.onAlarm());
        HandlerUtils.waitForIdle(handler, TEST_TIMEOUT_MS);

        Dhcp6Packet packet = getNextDhcp6Packet();
        assertTrue(packet instanceof Dhcp6RenewPacket);

        // Reply with a different prefix with requested one, check if all global IPv6 addresses
        // will be deleted and loss the IPv6 provisioning.
        final IpPrefix prefix1 = new IpPrefix("2001:db8:2::/64");
        final ByteBuffer iapd = Dhcp6Packet.buildIaPdOption(packet.getIaId(), 3600 /* t1*/,
                4500 /* t2 */, 4500 /* preferred */, 7200 /* valid */, prefix1.getRawAddress(),
                (byte) 64 /* prefix length */);
        mPacketReader.sendResponse(buildDhcp6Reply(packet, iapd.array(), mClientMac,
                (Inet6Address) mClientIpAddress, false /* rapidCommit */));
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningFailure(any());
    }

    @Test
    @SignatureRequiredTest(reason = "InterfaceParams.getByName requires CAP_NET_ADMIN")
    public void testSendRtmDelAddressMethod() throws Exception {
        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIPv4()
                .build();
        startIpClientProvisioning(config);

        final LinkProperties lp = doIpv6OnlyProvisioning();
        assertNotNull(lp);
        assertEquals(3, lp.getLinkAddresses().size()); // IPv6 privacy, stable privacy, link-local

        clearInvocations(mCb);

        // Delete all global IPv6 addresses, then that will trigger onProvisioningFailure callback.
        final InterfaceParams params = InterfaceParams.getByName(mIfaceName);
        for (LinkAddress la : lp.getLinkAddresses()) {
            if (la.isGlobalPreferred()) {
                NetlinkUtils.sendRtmDelAddressRequest(params.index, (Inet6Address) la.getAddress(),
                        (short) la.getPrefixLength());
                verify(mCb, timeout(TEST_TIMEOUT_MS)).onLinkPropertiesChange(argThat(
                        x -> !x.getLinkAddresses().contains(la)
                ));
            }
        }
        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningFailure(any());
    }

    @Test
    @SignatureRequiredTest(reason = "requires mocked netd to read/write IPv6 sysctl")
    public void testIpv6SysctlsRestAfterStoppingIpClient() throws Exception {
        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
                .withoutIPv4()
                .build();
        // dad_transmits has been set to 0 in disableIpv6ProvisioningDelays, re-enable
        // dad_transmits for testing, production code will restore all IPv6 sysctls at
        // StoppedState#enter anyway, read this parameter value after IpClient shutdown
        // to check if that's default value 1.
        mNetd.setProcSysNet(INetd.IPV6, INetd.CONF, mIfaceName, "dad_transmits", "1");
        startIpClientProvisioning(config);
        verify(mNetd, timeout(TEST_TIMEOUT_MS)).interfaceSetEnableIPv6(mIfaceName, true);
        doIpv6OnlyProvisioning();

        // Shutdown IpClient and check if the IPv6 sysctls: accept_ra, accept_ra_defrtr and
        // dad_transmits have been reset to the default values.
        mIpc.shutdown();
        awaitIpClientShutdown();
        final int dadTransmits = Integer.parseUnsignedInt(
                mNetd.getProcSysNet(INetd.IPV6, INetd.CONF, mIfaceName, "dad_transmits"));
        assertEquals(1, dadTransmits);
        final int acceptRa = Integer.parseUnsignedInt(
                mNetd.getProcSysNet(INetd.IPV6, INetd.CONF, mIfaceName, "accept_ra"));
        assertEquals(2, acceptRa);
        final int acceptRaDefRtr = Integer.parseUnsignedInt(
                mNetd.getProcSysNet(INetd.IPV6, INetd.CONF, mIfaceName, "accept_ra_defrtr"));
        assertEquals(1, acceptRaDefRtr);
    }
}