/*
 * Copyright (C) 2010 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;

import static android.net.RouteInfo.RTN_THROW;
import static android.net.RouteInfo.RTN_UNICAST;
import static android.net.RouteInfo.RTN_UNREACHABLE;

import static com.android.testutils.ParcelUtilsKt.assertParcelSane;
import static com.android.testutils.ParcelUtilsKt.assertParcelingIsLossless;
import static com.android.testutils.ParcelUtilsKt.parcelingRoundTrip;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotEquals;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;

import android.net.LinkProperties.ProvisioningChange;
import android.net.util.LinkPropertiesUtils.CompareResult;
import android.os.Build;
import android.system.OsConstants;
import android.util.ArraySet;

import androidx.core.os.BuildCompat;
import androidx.test.filters.SmallTest;
import androidx.test.runner.AndroidJUnit4;

import com.android.testutils.DevSdkIgnoreRule;
import com.android.testutils.DevSdkIgnoreRule.IgnoreAfter;
import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo;

import org.junit.Rule;
import org.junit.Test;
import org.junit.runner.RunWith;

import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Set;

@RunWith(AndroidJUnit4.class)
@SmallTest
public class LinkPropertiesTest {
    @Rule
    public final DevSdkIgnoreRule ignoreRule = new DevSdkIgnoreRule();

    private static final InetAddress ADDRV4 = address("75.208.6.1");
    private static final InetAddress ADDRV6 = address("2001:0db8:85a3:0000:0000:8a2e:0370:7334");
    private static final InetAddress DNS1 = address("75.208.7.1");
    private static final InetAddress DNS2 = address("69.78.7.1");
    private static final InetAddress DNS6 = address("2001:4860:4860::8888");
    private static final InetAddress PRIVDNS1 = address("1.1.1.1");
    private static final InetAddress PRIVDNS2 = address("1.0.0.1");
    private static final InetAddress PRIVDNS6 = address("2606:4700:4700::1111");
    private static final InetAddress PCSCFV4 = address("10.77.25.37");
    private static final InetAddress PCSCFV6 = address("2001:0db8:85a3:0000:0000:8a2e:0370:1");
    private static final InetAddress GATEWAY1 = address("75.208.8.1");
    private static final InetAddress GATEWAY2 = address("69.78.8.1");
    private static final InetAddress GATEWAY61 = address("fe80::6:0000:613");
    private static final InetAddress GATEWAY62 = address("fe80::6:22%lo");
    private static final InetAddress TESTIPV4ADDR = address("192.168.47.42");
    private static final InetAddress TESTIPV6ADDR = address("fe80::7:33%43");
    private static final Inet4Address DHCPSERVER = (Inet4Address) address("192.0.2.1");
    private static final String NAME = "qmi0";
    private static final String DOMAINS = "google.com";
    private static final String PRIV_DNS_SERVER_NAME = "private.dns.com";
    private static final String TCP_BUFFER_SIZES = "524288,1048576,2097152,262144,524288,1048576";
    private static final int MTU = 1500;
    private static final LinkAddress LINKADDRV4 = new LinkAddress(ADDRV4, 32);
    private static final LinkAddress LINKADDRV6 = new LinkAddress(ADDRV6, 128);
    private static final LinkAddress LINKADDRV6LINKLOCAL = new LinkAddress("fe80::1/64");
    private static final Uri CAPPORT_API_URL = Uri.parse("https://test.example.com/capportapi");

    // CaptivePortalData cannot be in a constant as it does not exist on Q.
    // The test runner also crashes when scanning for tests if it is a return type.
    private static Object getCaptivePortalData() {
        return new CaptivePortalData.Builder()
                .setVenueInfoUrl(Uri.parse("https://test.example.com/venue")).build();
    }

    private static InetAddress address(String addrString) {
        return InetAddresses.parseNumericAddress(addrString);
    }

    private static boolean isAtLeastR() {
        // BuildCompat.isAtLeastR is documented to return false on release SDKs (including R)
        return Build.VERSION.SDK_INT > Build.VERSION_CODES.Q || BuildCompat.isAtLeastR();
    }

    private void checkEmpty(final LinkProperties lp) {
        assertEquals(0, lp.getAllInterfaceNames().size());
        assertEquals(0, lp.getAllAddresses().size());
        assertEquals(0, lp.getDnsServers().size());
        assertEquals(0, lp.getValidatedPrivateDnsServers().size());
        assertEquals(0, lp.getPcscfServers().size());
        assertEquals(0, lp.getAllRoutes().size());
        assertEquals(0, lp.getAllLinkAddresses().size());
        assertEquals(0, lp.getStackedLinks().size());
        assertEquals(0, lp.getMtu());
        assertNull(lp.getPrivateDnsServerName());
        assertNull(lp.getDomains());
        assertNull(lp.getHttpProxy());
        assertNull(lp.getTcpBufferSizes());
        assertNull(lp.getNat64Prefix());
        assertFalse(lp.isProvisioned());
        assertFalse(lp.isIpv4Provisioned());
        assertFalse(lp.isIpv6Provisioned());
        assertFalse(lp.isPrivateDnsActive());

        if (isAtLeastR()) {
            assertNull(lp.getDhcpServerAddress());
            assertFalse(lp.isWakeOnLanSupported());
            assertNull(lp.getCaptivePortalApiUrl());
            assertNull(lp.getCaptivePortalData());
        }
    }

    private LinkProperties makeTestObject() {
        final LinkProperties lp = new LinkProperties();
        lp.setInterfaceName(NAME);
        lp.addLinkAddress(LINKADDRV4);
        lp.addLinkAddress(LINKADDRV6);
        lp.addDnsServer(DNS1);
        lp.addDnsServer(DNS2);
        lp.addValidatedPrivateDnsServer(PRIVDNS1);
        lp.addValidatedPrivateDnsServer(PRIVDNS2);
        lp.setUsePrivateDns(true);
        lp.setPrivateDnsServerName(PRIV_DNS_SERVER_NAME);
        lp.addPcscfServer(PCSCFV6);
        lp.setDomains(DOMAINS);
        lp.addRoute(new RouteInfo(GATEWAY1));
        lp.addRoute(new RouteInfo(GATEWAY2));
        lp.setHttpProxy(ProxyInfo.buildDirectProxy("test", 8888));
        lp.setMtu(MTU);
        lp.setTcpBufferSizes(TCP_BUFFER_SIZES);
        lp.setNat64Prefix(new IpPrefix("2001:db8:0:64::/96"));
        if (isAtLeastR()) {
            lp.setDhcpServerAddress(DHCPSERVER);
            lp.setWakeOnLanSupported(true);
            lp.setCaptivePortalApiUrl(CAPPORT_API_URL);
            lp.setCaptivePortalData((CaptivePortalData) getCaptivePortalData());
        }
        return lp;
    }

    public void assertLinkPropertiesEqual(LinkProperties source, LinkProperties target) {
        // Check implementation of equals(), element by element.
        assertTrue(source.isIdenticalInterfaceName(target));
        assertTrue(target.isIdenticalInterfaceName(source));

        assertTrue(source.isIdenticalAddresses(target));
        assertTrue(target.isIdenticalAddresses(source));

        assertTrue(source.isIdenticalDnses(target));
        assertTrue(target.isIdenticalDnses(source));

        assertTrue(source.isIdenticalPrivateDns(target));
        assertTrue(target.isIdenticalPrivateDns(source));

        assertTrue(source.isIdenticalValidatedPrivateDnses(target));
        assertTrue(target.isIdenticalValidatedPrivateDnses(source));

        assertTrue(source.isIdenticalPcscfs(target));
        assertTrue(target.isIdenticalPcscfs(source));

        assertTrue(source.isIdenticalRoutes(target));
        assertTrue(target.isIdenticalRoutes(source));

        assertTrue(source.isIdenticalHttpProxy(target));
        assertTrue(target.isIdenticalHttpProxy(source));

        assertTrue(source.isIdenticalStackedLinks(target));
        assertTrue(target.isIdenticalStackedLinks(source));

        assertTrue(source.isIdenticalMtu(target));
        assertTrue(target.isIdenticalMtu(source));

        assertTrue(source.isIdenticalTcpBufferSizes(target));
        assertTrue(target.isIdenticalTcpBufferSizes(source));

        if (isAtLeastR()) {
            assertTrue(source.isIdenticalDhcpServerAddress(target));
            assertTrue(source.isIdenticalDhcpServerAddress(source));

            assertTrue(source.isIdenticalWakeOnLan(target));
            assertTrue(target.isIdenticalWakeOnLan(source));

            assertTrue(source.isIdenticalCaptivePortalApiUrl(target));
            assertTrue(target.isIdenticalCaptivePortalApiUrl(source));

            assertTrue(source.isIdenticalCaptivePortalData(target));
            assertTrue(target.isIdenticalCaptivePortalData(source));
        }

        // Check result of equals().
        assertTrue(source.equals(target));
        assertTrue(target.equals(source));

        // Check hashCode.
        assertEquals(source.hashCode(), target.hashCode());
    }

    @Test
    public void testEqualsNull() {
        LinkProperties source = new LinkProperties();
        LinkProperties target = new LinkProperties();

        assertFalse(source == target);
        assertLinkPropertiesEqual(source, target);
    }

    @Test
    public void testEqualsSameOrder() throws Exception {
        LinkProperties source = new LinkProperties();
        source.setInterfaceName(NAME);
        // set 2 link addresses
        source.addLinkAddress(LINKADDRV4);
        source.addLinkAddress(LINKADDRV6);
        // set 2 dnses
        source.addDnsServer(DNS1);
        source.addDnsServer(DNS2);
        // set 1 pcscf
        source.addPcscfServer(PCSCFV6);
        // set 2 gateways
        source.addRoute(new RouteInfo(GATEWAY1));
        source.addRoute(new RouteInfo(GATEWAY2));
        source.setMtu(MTU);

        LinkProperties target = new LinkProperties();

        // All fields are same
        target.setInterfaceName(NAME);
        target.addLinkAddress(LINKADDRV4);
        target.addLinkAddress(LINKADDRV6);
        target.addDnsServer(DNS1);
        target.addDnsServer(DNS2);
        target.addPcscfServer(PCSCFV6);
        target.addRoute(new RouteInfo(GATEWAY1));
        target.addRoute(new RouteInfo(GATEWAY2));
        target.setMtu(MTU);

        assertLinkPropertiesEqual(source, target);

        target.clear();
        // change Interface Name
        target.setInterfaceName("qmi1");
        target.addLinkAddress(LINKADDRV4);
        target.addLinkAddress(LINKADDRV6);
        target.addDnsServer(DNS1);
        target.addDnsServer(DNS2);
        target.addPcscfServer(PCSCFV6);
        target.addRoute(new RouteInfo(GATEWAY1));
        target.addRoute(new RouteInfo(GATEWAY2));
        target.setMtu(MTU);
        assertFalse(source.equals(target));

        target.clear();
        target.setInterfaceName(NAME);
        // change link addresses
        target.addLinkAddress(new LinkAddress(address("75.208.6.2"), 32));
        target.addLinkAddress(LINKADDRV6);
        target.addDnsServer(DNS1);
        target.addDnsServer(DNS2);
        target.addPcscfServer(PCSCFV6);
        target.addRoute(new RouteInfo(GATEWAY1));
        target.addRoute(new RouteInfo(GATEWAY2));
        target.setMtu(MTU);
        assertFalse(source.equals(target));

        target.clear();
        target.setInterfaceName(NAME);
        target.addLinkAddress(LINKADDRV4);
        target.addLinkAddress(LINKADDRV6);
        // change dnses
        target.addDnsServer(address("75.208.7.2"));
        target.addDnsServer(DNS2);
        target.addPcscfServer(PCSCFV6);
        target.addRoute(new RouteInfo(GATEWAY1));
        target.addRoute(new RouteInfo(GATEWAY2));
        target.setMtu(MTU);
        assertFalse(source.equals(target));

        target.clear();
        target.setInterfaceName(NAME);
        target.addLinkAddress(LINKADDRV4);
        target.addLinkAddress(LINKADDRV6);
        target.addDnsServer(address("75.208.7.2"));
        target.addDnsServer(DNS2);
        // change pcscf
        target.addPcscfServer(address("2001::1"));
        target.addRoute(new RouteInfo(GATEWAY1));
        target.addRoute(new RouteInfo(GATEWAY2));
        target.setMtu(MTU);
        assertFalse(source.equals(target));

        target.clear();
        target.setInterfaceName(NAME);
        target.addLinkAddress(LINKADDRV4);
        target.addLinkAddress(LINKADDRV6);
        target.addDnsServer(DNS1);
        target.addDnsServer(DNS2);
        // change gateway
        target.addRoute(new RouteInfo(address("75.208.8.2")));
        target.setMtu(MTU);
        target.addRoute(new RouteInfo(GATEWAY2));
        assertFalse(source.equals(target));

        target.clear();
        target.setInterfaceName(NAME);
        target.addLinkAddress(LINKADDRV4);
        target.addLinkAddress(LINKADDRV6);
        target.addDnsServer(DNS1);
        target.addDnsServer(DNS2);
        target.addRoute(new RouteInfo(GATEWAY1));
        target.addRoute(new RouteInfo(GATEWAY2));
        // change mtu
        target.setMtu(1440);
        assertFalse(source.equals(target));
    }

    @Test
    public void testEqualsDifferentOrder() throws Exception {
        LinkProperties source = new LinkProperties();
        source.setInterfaceName(NAME);
        // set 2 link addresses
        source.addLinkAddress(LINKADDRV4);
        source.addLinkAddress(LINKADDRV6);
        // set 2 dnses
        source.addDnsServer(DNS1);
        source.addDnsServer(DNS2);
        // set 2 gateways
        source.addRoute(new RouteInfo(LINKADDRV4, GATEWAY1));
        source.addRoute(new RouteInfo(GATEWAY2));
        source.setMtu(MTU);

        LinkProperties target = new LinkProperties();
        // Exchange order
        target.setInterfaceName(NAME);
        target.addLinkAddress(LINKADDRV6);
        target.addLinkAddress(LINKADDRV4);
        target.addDnsServer(DNS2);
        target.addDnsServer(DNS1);
        target.addRoute(new RouteInfo(GATEWAY2));
        target.addRoute(new RouteInfo(LINKADDRV4, GATEWAY1));
        target.setMtu(MTU);

        assertLinkPropertiesEqual(source, target);
    }

    @Test
    public void testEqualsDuplicated() throws Exception {
        LinkProperties source = new LinkProperties();
        // set 3 link addresses, eg, [A, A, B]
        source.addLinkAddress(LINKADDRV4);
        source.addLinkAddress(LINKADDRV4);
        source.addLinkAddress(LINKADDRV6);

        LinkProperties target = new LinkProperties();
        // set 3 link addresses, eg, [A, B, B]
        target.addLinkAddress(LINKADDRV4);
        target.addLinkAddress(LINKADDRV6);
        target.addLinkAddress(LINKADDRV6);

        assertLinkPropertiesEqual(source, target);
    }

    private void assertAllRoutesHaveInterface(String iface, LinkProperties lp) {
        for (RouteInfo r : lp.getRoutes()) {
            assertEquals(iface, r.getInterface());
        }
    }

    private void assertAllRoutesNotHaveInterface(String iface, LinkProperties lp) {
        for (RouteInfo r : lp.getRoutes()) {
            assertNotEquals(iface, r.getInterface());
        }
    }

    @Test
    public void testRouteInterfaces() {
        LinkAddress prefix1 = new LinkAddress(address("2001:db8:1::"), 48);
        LinkAddress prefix2 = new LinkAddress(address("2001:db8:2::"), 48);
        InetAddress address = ADDRV6;

        // Add a route with no interface to a LinkProperties with no interface. No errors.
        LinkProperties lp = new LinkProperties();
        RouteInfo r = new RouteInfo(prefix1, address, null);
        assertTrue(lp.addRoute(r));
        assertEquals(1, lp.getRoutes().size());
        assertAllRoutesHaveInterface(null, lp);

        // Adding the same route twice has no effect.
        assertFalse(lp.addRoute(r));
        assertEquals(1, lp.getRoutes().size());

        // Add a route with an interface. Expect an exception.
        r = new RouteInfo(prefix2, address, "wlan0");
        try {
          lp.addRoute(r);
          fail("Adding wlan0 route to LP with no interface, expect exception");
        } catch (IllegalArgumentException expected) {}

        // Change the interface name. All the routes should change their interface name too.
        lp.setInterfaceName("rmnet0");
        assertAllRoutesHaveInterface("rmnet0", lp);
        assertAllRoutesNotHaveInterface(null, lp);
        assertAllRoutesNotHaveInterface("wlan0", lp);

        // Now add a route with the wrong interface. This causes an exception too.
        try {
          lp.addRoute(r);
          fail("Adding wlan0 route to rmnet0 LP, expect exception");
        } catch (IllegalArgumentException expected) {}

        // If the interface name matches, the route is added.
        r = new RouteInfo(prefix2, null, "wlan0");
        lp.setInterfaceName("wlan0");
        lp.addRoute(r);
        assertEquals(2, lp.getRoutes().size());
        assertAllRoutesHaveInterface("wlan0", lp);
        assertAllRoutesNotHaveInterface("rmnet0", lp);

        // Routes with null interfaces are converted to wlan0.
        r = RouteInfo.makeHostRoute(ADDRV6, null);
        lp.addRoute(r);
        assertEquals(3, lp.getRoutes().size());
        assertAllRoutesHaveInterface("wlan0", lp);

        // Check comparisons work.
        LinkProperties lp2 = new LinkProperties(lp);
        assertAllRoutesHaveInterface("wlan0", lp2);
        // LinkProperties#compareAllRoutes exists both in R and before R, but the return type
        // changed in R, so a test compiled with the R version of LinkProperties cannot run on Q.
        if (isAtLeastR()) {
            assertEquals(0, lp.compareAllRoutes(lp2).added.size());
            assertEquals(0, lp.compareAllRoutes(lp2).removed.size());
        }

        lp2.setInterfaceName("p2p0");
        assertAllRoutesHaveInterface("p2p0", lp2);
        assertAllRoutesNotHaveInterface("wlan0", lp2);
        if (isAtLeastR()) {
            assertEquals(3, lp.compareAllRoutes(lp2).added.size());
            assertEquals(3, lp.compareAllRoutes(lp2).removed.size());
        }

        // Remove route with incorrect interface, no route removed.
        lp.removeRoute(new RouteInfo(prefix2, null, null));
        assertEquals(3, lp.getRoutes().size());

        // Check remove works when interface is correct.
        lp.removeRoute(new RouteInfo(prefix2, null, "wlan0"));
        assertEquals(2, lp.getRoutes().size());
        assertAllRoutesHaveInterface("wlan0", lp);
        assertAllRoutesNotHaveInterface("p2p0", lp);
    }

    @Test
    public void testStackedInterfaces() {
        LinkProperties rmnet0 = new LinkProperties();
        rmnet0.setInterfaceName("rmnet0");
        rmnet0.addLinkAddress(LINKADDRV6);

        LinkProperties clat4 = new LinkProperties();
        clat4.setInterfaceName("clat4");
        clat4.addLinkAddress(LINKADDRV4);

        assertEquals(0, rmnet0.getStackedLinks().size());
        assertEquals(1, rmnet0.getAddresses().size());
        assertEquals(1, rmnet0.getLinkAddresses().size());
        assertEquals(1, rmnet0.getAllAddresses().size());
        assertEquals(1, rmnet0.getAllLinkAddresses().size());
        assertEquals(1, rmnet0.getAllInterfaceNames().size());
        assertEquals("rmnet0", rmnet0.getAllInterfaceNames().get(0));

        rmnet0.addStackedLink(clat4);
        assertEquals(1, rmnet0.getStackedLinks().size());
        assertEquals(1, rmnet0.getAddresses().size());
        assertEquals(1, rmnet0.getLinkAddresses().size());
        assertEquals(2, rmnet0.getAllAddresses().size());
        assertEquals(2, rmnet0.getAllLinkAddresses().size());
        assertEquals(2, rmnet0.getAllInterfaceNames().size());
        assertEquals("rmnet0", rmnet0.getAllInterfaceNames().get(0));
        assertEquals("clat4", rmnet0.getAllInterfaceNames().get(1));

        rmnet0.addStackedLink(clat4);
        assertEquals(1, rmnet0.getStackedLinks().size());
        assertEquals(1, rmnet0.getAddresses().size());
        assertEquals(1, rmnet0.getLinkAddresses().size());
        assertEquals(2, rmnet0.getAllAddresses().size());
        assertEquals(2, rmnet0.getAllLinkAddresses().size());
        assertEquals(2, rmnet0.getAllInterfaceNames().size());
        assertEquals("rmnet0", rmnet0.getAllInterfaceNames().get(0));
        assertEquals("clat4", rmnet0.getAllInterfaceNames().get(1));

        assertEquals(0, clat4.getStackedLinks().size());

        // Modify an item in the returned collection to see what happens.
        for (LinkProperties link : rmnet0.getStackedLinks()) {
            if (link.getInterfaceName().equals("clat4")) {
               link.setInterfaceName("newname");
            }
        }
        for (LinkProperties link : rmnet0.getStackedLinks()) {
            assertFalse("newname".equals(link.getInterfaceName()));
        }

        assertTrue(rmnet0.removeStackedLink("clat4"));
        assertEquals(0, rmnet0.getStackedLinks().size());
        assertEquals(1, rmnet0.getAddresses().size());
        assertEquals(1, rmnet0.getLinkAddresses().size());
        assertEquals(1, rmnet0.getAllAddresses().size());
        assertEquals(1, rmnet0.getAllLinkAddresses().size());
        assertEquals(1, rmnet0.getAllInterfaceNames().size());
        assertEquals("rmnet0", rmnet0.getAllInterfaceNames().get(0));

        assertFalse(rmnet0.removeStackedLink("clat4"));
    }

    private LinkAddress getFirstLinkAddress(LinkProperties lp) {
        return lp.getLinkAddresses().iterator().next();
    }

    @Test
    public void testAddressMethods() {
        LinkProperties lp = new LinkProperties();

        // No addresses.
        assertFalse(lp.hasIpv4Address());
        assertFalse(lp.hasGlobalIpv6Address());

        // Addresses on stacked links don't count.
        LinkProperties stacked = new LinkProperties();
        stacked.setInterfaceName("stacked");
        lp.addStackedLink(stacked);
        stacked.addLinkAddress(LINKADDRV4);
        stacked.addLinkAddress(LINKADDRV6);
        assertTrue(stacked.hasIpv4Address());
        assertTrue(stacked.hasGlobalIpv6Address());
        assertFalse(lp.hasIpv4Address());
        assertFalse(lp.hasGlobalIpv6Address());
        lp.removeStackedLink("stacked");
        assertFalse(lp.hasIpv4Address());
        assertFalse(lp.hasGlobalIpv6Address());

        // Addresses on the base link.
        // Check the return values of hasIpvXAddress and ensure the add/remove methods return true
        // iff something changes.
        assertEquals(0, lp.getLinkAddresses().size());
        assertTrue(lp.addLinkAddress(LINKADDRV6));
        assertEquals(1, lp.getLinkAddresses().size());
        assertFalse(lp.hasIpv4Address());
        assertTrue(lp.hasGlobalIpv6Address());

        assertTrue(lp.removeLinkAddress(LINKADDRV6));
        assertEquals(0, lp.getLinkAddresses().size());

        assertTrue(lp.addLinkAddress(LINKADDRV6LINKLOCAL));
        assertEquals(1, lp.getLinkAddresses().size());
        assertFalse(lp.hasGlobalIpv6Address());

        assertTrue(lp.addLinkAddress(LINKADDRV4));
        assertEquals(2, lp.getLinkAddresses().size());
        assertTrue(lp.hasIpv4Address());
        assertFalse(lp.hasGlobalIpv6Address());

        assertTrue(lp.addLinkAddress(LINKADDRV6));
        assertEquals(3, lp.getLinkAddresses().size());
        assertTrue(lp.hasIpv4Address());
        assertTrue(lp.hasGlobalIpv6Address());

        assertTrue(lp.removeLinkAddress(LINKADDRV6LINKLOCAL));
        assertEquals(2, lp.getLinkAddresses().size());
        assertTrue(lp.hasIpv4Address());
        assertTrue(lp.hasGlobalIpv6Address());

        // Adding an address twice has no effect.
        // Removing an address that's not present has no effect.
        assertFalse(lp.addLinkAddress(LINKADDRV4));
        assertEquals(2, lp.getLinkAddresses().size());
        assertTrue(lp.hasIpv4Address());
        assertTrue(lp.removeLinkAddress(LINKADDRV4));
        assertEquals(1, lp.getLinkAddresses().size());
        assertFalse(lp.hasIpv4Address());
        assertFalse(lp.removeLinkAddress(LINKADDRV4));
        assertEquals(1, lp.getLinkAddresses().size());

        // Adding an address that's already present but with different properties causes the
        // existing address to be updated and returns true.
        // Start with only LINKADDRV6.
        assertEquals(1, lp.getLinkAddresses().size());
        assertEquals(LINKADDRV6, getFirstLinkAddress(lp));

        // Create a LinkAddress object for the same address, but with different flags.
        LinkAddress deprecated = new LinkAddress(ADDRV6, 128,
                OsConstants.IFA_F_DEPRECATED, OsConstants.RT_SCOPE_UNIVERSE);
        assertTrue(deprecated.isSameAddressAs(LINKADDRV6));
        assertFalse(deprecated.equals(LINKADDRV6));

        // Check that adding it updates the existing address instead of adding a new one.
        assertTrue(lp.addLinkAddress(deprecated));
        assertEquals(1, lp.getLinkAddresses().size());
        assertEquals(deprecated, getFirstLinkAddress(lp));
        assertFalse(LINKADDRV6.equals(getFirstLinkAddress(lp)));

        // Removing LINKADDRV6 removes deprecated, because removing addresses ignores properties.
        assertTrue(lp.removeLinkAddress(LINKADDRV6));
        assertEquals(0, lp.getLinkAddresses().size());
    }

    @Test
    public void testLinkAddresses() {
        final LinkProperties lp = new LinkProperties();
        lp.addLinkAddress(LINKADDRV4);
        lp.addLinkAddress(LINKADDRV6);

        final LinkProperties lp2 = new LinkProperties();
        lp2.addLinkAddress(LINKADDRV6);

        final LinkProperties lp3 = new LinkProperties();
        final List<LinkAddress> linkAddresses = Arrays.asList(LINKADDRV4);
        lp3.setLinkAddresses(linkAddresses);

        assertFalse(lp.equals(lp2));
        assertFalse(lp2.equals(lp3));

        lp.removeLinkAddress(LINKADDRV4);
        assertTrue(lp.equals(lp2));

        lp2.setLinkAddresses(lp3.getLinkAddresses());
        assertTrue(lp2.equals(lp3));
    }

    @Test
    public void testNat64Prefix() throws Exception {
        LinkProperties lp = new LinkProperties();
        lp.addLinkAddress(LINKADDRV4);
        lp.addLinkAddress(LINKADDRV6);

        assertNull(lp.getNat64Prefix());

        IpPrefix p = new IpPrefix("64:ff9b::/96");
        lp.setNat64Prefix(p);
        assertEquals(p, lp.getNat64Prefix());

        p = new IpPrefix("2001:db8:a:b:1:2:3::/96");
        lp.setNat64Prefix(p);
        assertEquals(p, lp.getNat64Prefix());

        p = new IpPrefix("2001:db8:a:b:1:2::/80");
        try {
            lp.setNat64Prefix(p);
        } catch (IllegalArgumentException expected) {
        }

        p = new IpPrefix("64:ff9b::/64");
        try {
            lp.setNat64Prefix(p);
        } catch (IllegalArgumentException expected) {
        }

        assertEquals(new IpPrefix("2001:db8:a:b:1:2:3::/96"), lp.getNat64Prefix());

        lp.setNat64Prefix(null);
        assertNull(lp.getNat64Prefix());
    }

    @Test
    public void testIsProvisioned() {
        LinkProperties lp4 = new LinkProperties();
        assertFalse("v4only:empty", lp4.isProvisioned());
        lp4.addLinkAddress(LINKADDRV4);
        assertFalse("v4only:addr-only", lp4.isProvisioned());
        lp4.addDnsServer(DNS1);
        assertFalse("v4only:addr+dns", lp4.isProvisioned());
        lp4.addRoute(new RouteInfo(GATEWAY1));
        assertTrue("v4only:addr+dns+route", lp4.isProvisioned());
        assertTrue("v4only:addr+dns+route", lp4.isIpv4Provisioned());
        assertFalse("v4only:addr+dns+route", lp4.isIpv6Provisioned());

        LinkProperties lp6 = new LinkProperties();
        assertFalse("v6only:empty", lp6.isProvisioned());
        lp6.addLinkAddress(LINKADDRV6LINKLOCAL);
        assertFalse("v6only:fe80-only", lp6.isProvisioned());
        lp6.addDnsServer(DNS6);
        assertFalse("v6only:fe80+dns", lp6.isProvisioned());
        lp6.addRoute(new RouteInfo(GATEWAY61));
        assertFalse("v6only:fe80+dns+route", lp6.isProvisioned());
        lp6.addLinkAddress(LINKADDRV6);
        assertTrue("v6only:fe80+global+dns+route", lp6.isIpv6Provisioned());
        assertTrue("v6only:fe80+global+dns+route", lp6.isProvisioned());
        lp6.removeLinkAddress(LINKADDRV6LINKLOCAL);
        assertFalse("v6only:global+dns+route", lp6.isIpv4Provisioned());
        assertTrue("v6only:global+dns+route", lp6.isIpv6Provisioned());
        assertTrue("v6only:global+dns+route", lp6.isProvisioned());

        LinkProperties lp46 = new LinkProperties();
        lp46.addLinkAddress(LINKADDRV4);
        lp46.addLinkAddress(LINKADDRV6);
        lp46.addDnsServer(DNS1);
        lp46.addDnsServer(DNS6);
        assertFalse("dualstack:missing-routes", lp46.isProvisioned());
        lp46.addRoute(new RouteInfo(GATEWAY1));
        assertTrue("dualstack:v4-provisioned", lp46.isIpv4Provisioned());
        assertFalse("dualstack:v4-provisioned", lp46.isIpv6Provisioned());
        assertTrue("dualstack:v4-provisioned", lp46.isProvisioned());
        lp46.addRoute(new RouteInfo(GATEWAY61));
        assertTrue("dualstack:both-provisioned", lp46.isIpv4Provisioned());
        assertTrue("dualstack:both-provisioned", lp46.isIpv6Provisioned());
        assertTrue("dualstack:both-provisioned", lp46.isProvisioned());

        // A link with an IPv6 address and default route, but IPv4 DNS server.
        LinkProperties mixed = new LinkProperties();
        mixed.addLinkAddress(LINKADDRV6);
        mixed.addDnsServer(DNS1);
        mixed.addRoute(new RouteInfo(GATEWAY61));
        assertFalse("mixed:addr6+route6+dns4", mixed.isIpv4Provisioned());
        assertFalse("mixed:addr6+route6+dns4", mixed.isIpv6Provisioned());
        assertFalse("mixed:addr6+route6+dns4", mixed.isProvisioned());
    }

    @Test
    public void testCompareProvisioning() {
        LinkProperties v4lp = new LinkProperties();
        v4lp.addLinkAddress(LINKADDRV4);
        v4lp.addRoute(new RouteInfo(GATEWAY1));
        v4lp.addDnsServer(DNS1);
        assertTrue(v4lp.isProvisioned());

        LinkProperties v4r = new LinkProperties(v4lp);
        v4r.removeDnsServer(DNS1);
        assertFalse(v4r.isProvisioned());

        assertEquals(ProvisioningChange.STILL_NOT_PROVISIONED,
                LinkProperties.compareProvisioning(v4r, v4r));
        assertEquals(ProvisioningChange.LOST_PROVISIONING,
                LinkProperties.compareProvisioning(v4lp, v4r));
        assertEquals(ProvisioningChange.GAINED_PROVISIONING,
                LinkProperties.compareProvisioning(v4r, v4lp));
        assertEquals(ProvisioningChange.STILL_PROVISIONED,
                LinkProperties.compareProvisioning(v4lp, v4lp));

        // Check that losing IPv4 provisioning on a dualstack network is
        // seen as a total loss of provisioning.
        LinkProperties v6lp = new LinkProperties();
        v6lp.addLinkAddress(LINKADDRV6);
        v6lp.addRoute(new RouteInfo(GATEWAY61));
        v6lp.addDnsServer(DNS6);
        assertFalse(v6lp.isIpv4Provisioned());
        assertTrue(v6lp.isIpv6Provisioned());
        assertTrue(v6lp.isProvisioned());

        LinkProperties v46lp = new LinkProperties(v6lp);
        v46lp.addLinkAddress(LINKADDRV4);
        v46lp.addRoute(new RouteInfo(GATEWAY1));
        v46lp.addDnsServer(DNS1);
        assertTrue(v46lp.isIpv4Provisioned());
        assertTrue(v46lp.isIpv6Provisioned());
        assertTrue(v46lp.isProvisioned());

        assertEquals(ProvisioningChange.STILL_PROVISIONED,
                LinkProperties.compareProvisioning(v4lp, v46lp));
        assertEquals(ProvisioningChange.STILL_PROVISIONED,
                LinkProperties.compareProvisioning(v6lp, v46lp));
        assertEquals(ProvisioningChange.LOST_PROVISIONING,
                LinkProperties.compareProvisioning(v46lp, v6lp));
        assertEquals(ProvisioningChange.LOST_PROVISIONING,
                LinkProperties.compareProvisioning(v46lp, v4lp));

        // Check that losing and gaining a secondary router does not change
        // the provisioning status.
        LinkProperties v6lp2 = new LinkProperties(v6lp);
        v6lp2.addRoute(new RouteInfo(GATEWAY62));
        assertTrue(v6lp2.isProvisioned());

        assertEquals(ProvisioningChange.STILL_PROVISIONED,
                LinkProperties.compareProvisioning(v6lp2, v6lp));
        assertEquals(ProvisioningChange.STILL_PROVISIONED,
                LinkProperties.compareProvisioning(v6lp, v6lp2));
    }

    @Test
    public void testIsReachable() {
        final LinkProperties v4lp = new LinkProperties();
        assertFalse(v4lp.isReachable(DNS1));
        assertFalse(v4lp.isReachable(DNS2));

        // Add an on-link route, making the on-link DNS server reachable,
        // but there is still no IPv4 address.
        assertTrue(v4lp.addRoute(new RouteInfo(new IpPrefix(address("75.208.0.0"), 16))));
        assertFalse(v4lp.isReachable(DNS1));
        assertFalse(v4lp.isReachable(DNS2));

        // Adding an IPv4 address (right now, any IPv4 address) means we use
        // the routes to compute likely reachability.
        assertTrue(v4lp.addLinkAddress(new LinkAddress(ADDRV4, 16)));
        assertTrue(v4lp.isReachable(DNS1));
        assertFalse(v4lp.isReachable(DNS2));

        // Adding a default route makes the off-link DNS server reachable.
        assertTrue(v4lp.addRoute(new RouteInfo(GATEWAY1)));
        assertTrue(v4lp.isReachable(DNS1));
        assertTrue(v4lp.isReachable(DNS2));

        final LinkProperties v6lp = new LinkProperties();
        final InetAddress kLinkLocalDns = address("fe80::6:1");
        final InetAddress kLinkLocalDnsWithScope = address("fe80::6:2%43");
        final InetAddress kOnLinkDns = address("2001:db8:85a3::53");
        assertFalse(v6lp.isReachable(kLinkLocalDns));
        assertFalse(v6lp.isReachable(kLinkLocalDnsWithScope));
        assertFalse(v6lp.isReachable(kOnLinkDns));
        assertFalse(v6lp.isReachable(DNS6));

        // Add a link-local route, making the link-local DNS servers reachable. Because
        // we assume the presence of an IPv6 link-local address, link-local DNS servers
        // are considered reachable, but only those with a non-zero scope identifier.
        assertTrue(v6lp.addRoute(new RouteInfo(new IpPrefix(address("fe80::"), 64))));
        assertFalse(v6lp.isReachable(kLinkLocalDns));
        assertTrue(v6lp.isReachable(kLinkLocalDnsWithScope));
        assertFalse(v6lp.isReachable(kOnLinkDns));
        assertFalse(v6lp.isReachable(DNS6));

        // Add a link-local address--nothing changes.
        assertTrue(v6lp.addLinkAddress(LINKADDRV6LINKLOCAL));
        assertFalse(v6lp.isReachable(kLinkLocalDns));
        assertTrue(v6lp.isReachable(kLinkLocalDnsWithScope));
        assertFalse(v6lp.isReachable(kOnLinkDns));
        assertFalse(v6lp.isReachable(DNS6));

        // Add a global route on link, but no global address yet. DNS servers reachable
        // via a route that doesn't require a gateway: give them the benefit of the
        // doubt and hope the link-local source address suffices for communication.
        assertTrue(v6lp.addRoute(new RouteInfo(new IpPrefix(address("2001:db8:85a3::"), 64))));
        assertFalse(v6lp.isReachable(kLinkLocalDns));
        assertTrue(v6lp.isReachable(kLinkLocalDnsWithScope));
        assertTrue(v6lp.isReachable(kOnLinkDns));
        assertFalse(v6lp.isReachable(DNS6));

        // Add a global address; the on-link global address DNS server is (still)
        // presumed reachable.
        assertTrue(v6lp.addLinkAddress(new LinkAddress(ADDRV6, 64)));
        assertFalse(v6lp.isReachable(kLinkLocalDns));
        assertTrue(v6lp.isReachable(kLinkLocalDnsWithScope));
        assertTrue(v6lp.isReachable(kOnLinkDns));
        assertFalse(v6lp.isReachable(DNS6));

        // Adding a default route makes the off-link DNS server reachable.
        assertTrue(v6lp.addRoute(new RouteInfo(GATEWAY62)));
        assertFalse(v6lp.isReachable(kLinkLocalDns));
        assertTrue(v6lp.isReachable(kLinkLocalDnsWithScope));
        assertTrue(v6lp.isReachable(kOnLinkDns));
        assertTrue(v6lp.isReachable(DNS6));

        // Check isReachable on stacked links. This requires that the source IP address be assigned
        // on the interface returned by the route lookup.
        LinkProperties stacked = new LinkProperties();

        // Can't add a stacked link without an interface name.
        stacked.setInterfaceName("v4-test0");
        v6lp.addStackedLink(stacked);

        InetAddress stackedAddress = address("192.0.0.4");
        LinkAddress stackedLinkAddress = new LinkAddress(stackedAddress, 32);
        assertFalse(v6lp.isReachable(stackedAddress));
        stacked.addLinkAddress(stackedLinkAddress);
        assertFalse(v6lp.isReachable(stackedAddress));
        stacked.addRoute(new RouteInfo(stackedLinkAddress));
        assertTrue(stacked.isReachable(stackedAddress));
        assertTrue(v6lp.isReachable(stackedAddress));

        assertFalse(v6lp.isReachable(DNS1));
        stacked.addRoute(new RouteInfo((IpPrefix) null, stackedAddress));
        assertTrue(v6lp.isReachable(DNS1));
    }

    @Test
    public void testLinkPropertiesEnsureDirectlyConnectedRoutes() {
        // IPv4 case: no route added initially
        LinkProperties rmnet0 = new LinkProperties();
        rmnet0.setInterfaceName("rmnet0");
        rmnet0.addLinkAddress(new LinkAddress("10.0.0.2/8"));
        RouteInfo directRoute0 = new RouteInfo(new IpPrefix("10.0.0.0/8"), null,
                rmnet0.getInterfaceName());

        // Since no routes is added explicitly, getAllRoutes() should return empty.
        assertTrue(rmnet0.getAllRoutes().isEmpty());
        rmnet0.ensureDirectlyConnectedRoutes();
        // ensureDirectlyConnectedRoutes() should have added the missing local route.
        assertEqualRoutes(Collections.singletonList(directRoute0), rmnet0.getAllRoutes());

        // IPv4 case: both direct and default routes added initially
        LinkProperties rmnet1 = new LinkProperties();
        rmnet1.setInterfaceName("rmnet1");
        rmnet1.addLinkAddress(new LinkAddress("10.0.0.3/8"));
        RouteInfo defaultRoute1 = new RouteInfo((IpPrefix) null, address("10.0.0.1"),
                rmnet1.getInterfaceName());
        RouteInfo directRoute1 = new RouteInfo(new IpPrefix("10.0.0.0/8"), null,
                rmnet1.getInterfaceName());
        rmnet1.addRoute(defaultRoute1);
        rmnet1.addRoute(directRoute1);

        // Check added routes
        assertEqualRoutes(Arrays.asList(defaultRoute1, directRoute1), rmnet1.getAllRoutes());
        // ensureDirectlyConnectedRoutes() shouldn't change the routes since direct connected
        // route is already part of the configuration.
        rmnet1.ensureDirectlyConnectedRoutes();
        assertEqualRoutes(Arrays.asList(defaultRoute1, directRoute1), rmnet1.getAllRoutes());

        // IPv6 case: only default routes added initially
        LinkProperties rmnet2 = new LinkProperties();
        rmnet2.setInterfaceName("rmnet2");
        rmnet2.addLinkAddress(new LinkAddress("fe80::cafe/64"));
        rmnet2.addLinkAddress(new LinkAddress("2001:db8::2/64"));
        RouteInfo defaultRoute2 = new RouteInfo((IpPrefix) null, address("2001:db8::1"),
                rmnet2.getInterfaceName());
        RouteInfo directRoute2 = new RouteInfo(new IpPrefix("2001:db8::/64"), null,
                rmnet2.getInterfaceName());
        RouteInfo linkLocalRoute2 = new RouteInfo(new IpPrefix("fe80::/64"), null,
                rmnet2.getInterfaceName());
        rmnet2.addRoute(defaultRoute2);

        assertEqualRoutes(Arrays.asList(defaultRoute2), rmnet2.getAllRoutes());
        rmnet2.ensureDirectlyConnectedRoutes();
        assertEqualRoutes(Arrays.asList(defaultRoute2, directRoute2, linkLocalRoute2),
                rmnet2.getAllRoutes());

        // Corner case: no interface name
        LinkProperties rmnet3 = new LinkProperties();
        rmnet3.addLinkAddress(new LinkAddress("192.168.0.2/24"));
        RouteInfo directRoute3 = new RouteInfo(new IpPrefix("192.168.0.0/24"), null,
                rmnet3.getInterfaceName());

        assertTrue(rmnet3.getAllRoutes().isEmpty());
        rmnet3.ensureDirectlyConnectedRoutes();
        assertEqualRoutes(Collections.singletonList(directRoute3), rmnet3.getAllRoutes());

    }

    @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
    public void testCompareResult() {
        // Either adding or removing items
        compareResult(Arrays.asList(1, 2, 3, 4), Arrays.asList(1),
                Arrays.asList(2, 3, 4), new ArrayList<>());
        compareResult(Arrays.asList(1, 2), Arrays.asList(3, 2, 1, 4),
                new ArrayList<>(), Arrays.asList(3, 4));


        // adding and removing items at the same time
        compareResult(Arrays.asList(1, 2, 3, 4), Arrays.asList(2, 3, 4, 5),
                Arrays.asList(1), Arrays.asList(5));
        compareResult(Arrays.asList(1, 2, 3), Arrays.asList(4, 5, 6),
                Arrays.asList(1, 2, 3), Arrays.asList(4, 5, 6));

        // null cases
        compareResult(Arrays.asList(1, 2, 3), null, Arrays.asList(1, 2, 3), new ArrayList<>());
        compareResult(null, Arrays.asList(3, 2, 1), new ArrayList<>(), Arrays.asList(1, 2, 3));
        compareResult(null, null, new ArrayList<>(), new ArrayList<>());
    }

    private void assertEqualRoutes(Collection<RouteInfo> expected, Collection<RouteInfo> actual) {
        Set<RouteInfo> expectedSet = new ArraySet<>(expected);
        Set<RouteInfo> actualSet = new ArraySet<>(actual);
        // Duplicated entries in actual routes are considered failures
        assertEquals(actual.size(), actualSet.size());

        assertEquals(expectedSet, actualSet);
    }

    private <T> void compareResult(List<T> oldItems, List<T> newItems, List<T> expectRemoved,
            List<T> expectAdded) {
        CompareResult<T> result = new CompareResult<>(oldItems, newItems);
        assertEquals(new ArraySet<>(expectAdded), new ArraySet<>(result.added));
        assertEquals(new ArraySet<>(expectRemoved), (new ArraySet<>(result.removed)));
    }

    private static LinkProperties makeLinkPropertiesForParceling() {
        LinkProperties source = new LinkProperties();
        source.setInterfaceName(NAME);

        source.addLinkAddress(LINKADDRV4);
        source.addLinkAddress(LINKADDRV6);

        source.addDnsServer(DNS1);
        source.addDnsServer(DNS2);
        source.addDnsServer(GATEWAY62);

        source.addPcscfServer(TESTIPV4ADDR);
        source.addPcscfServer(TESTIPV6ADDR);

        source.setUsePrivateDns(true);
        source.setPrivateDnsServerName(PRIV_DNS_SERVER_NAME);

        source.setDomains(DOMAINS);

        source.addRoute(new RouteInfo(GATEWAY1));
        source.addRoute(new RouteInfo(GATEWAY2));

        source.addValidatedPrivateDnsServer(DNS6);
        source.addValidatedPrivateDnsServer(GATEWAY61);
        source.addValidatedPrivateDnsServer(TESTIPV6ADDR);

        source.setHttpProxy(ProxyInfo.buildDirectProxy("test", 8888));

        source.setMtu(MTU);

        source.setTcpBufferSizes(TCP_BUFFER_SIZES);

        source.setNat64Prefix(new IpPrefix("2001:db8:1:2:64:64::/96"));

        final LinkProperties stacked = new LinkProperties();
        stacked.setInterfaceName("test-stacked");
        source.addStackedLink(stacked);

        return source;
    }

    @Test @IgnoreAfter(Build.VERSION_CODES.Q)
    public void testLinkPropertiesParcelable_Q() throws Exception {
        final LinkProperties source = makeLinkPropertiesForParceling();
        assertParcelSane(source, 14 /* fieldCount */);
    }

    @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
    public void testLinkPropertiesParcelable() throws Exception {
        final LinkProperties source = makeLinkPropertiesForParceling();

        source.setWakeOnLanSupported(true);
        source.setCaptivePortalApiUrl(CAPPORT_API_URL);
        source.setCaptivePortalData((CaptivePortalData) getCaptivePortalData());
        source.setDhcpServerAddress((Inet4Address) GATEWAY1);
        assertParcelSane(new LinkProperties(source, true /* parcelSensitiveFields */),
                18 /* fieldCount */);

        // Verify that without using a sensitiveFieldsParcelingCopy, sensitive fields are cleared.
        final LinkProperties sanitized = new LinkProperties(source);
        sanitized.setCaptivePortalApiUrl(null);
        sanitized.setCaptivePortalData(null);
        assertEquals(sanitized, parcelingRoundTrip(source));
    }

    // Parceling of the scope was broken until Q-QPR2
    @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
    public void testLinkLocalDnsServerParceling() throws Exception {
        final String strAddress = "fe80::1%lo";
        final LinkProperties lp = new LinkProperties();
        lp.addDnsServer(address(strAddress));
        final LinkProperties unparceled = parcelingRoundTrip(lp);
        // Inet6Address#equals does not test for the scope id
        assertEquals(strAddress, unparceled.getDnsServers().get(0).getHostAddress());
    }

    @Test
    public void testParcelUninitialized() throws Exception {
        LinkProperties empty = new LinkProperties();
        assertParcelingIsLossless(empty);
    }

    @Test
    public void testConstructor() {
        LinkProperties lp = new LinkProperties();
        checkEmpty(lp);
        assertLinkPropertiesEqual(lp, new LinkProperties(lp));
        assertLinkPropertiesEqual(lp, new LinkProperties());

        lp = makeTestObject();
        assertLinkPropertiesEqual(lp, new LinkProperties(lp));
    }

    @Test
    public void testDnsServers() {
        final LinkProperties lp = new LinkProperties();
        final List<InetAddress> dnsServers = Arrays.asList(DNS1, DNS2);
        lp.setDnsServers(dnsServers);
        assertEquals(2, lp.getDnsServers().size());
        assertEquals(DNS1, lp.getDnsServers().get(0));
        assertEquals(DNS2, lp.getDnsServers().get(1));

        lp.removeDnsServer(DNS1);
        assertEquals(1, lp.getDnsServers().size());
        assertEquals(DNS2, lp.getDnsServers().get(0));

        lp.addDnsServer(DNS6);
        assertEquals(2, lp.getDnsServers().size());
        assertEquals(DNS2, lp.getDnsServers().get(0));
        assertEquals(DNS6, lp.getDnsServers().get(1));
    }

    @Test
    public void testValidatedPrivateDnsServers() {
        final LinkProperties lp = new LinkProperties();
        final List<InetAddress> privDnsServers = Arrays.asList(PRIVDNS1, PRIVDNS2);
        lp.setValidatedPrivateDnsServers(privDnsServers);
        assertEquals(2, lp.getValidatedPrivateDnsServers().size());
        assertEquals(PRIVDNS1, lp.getValidatedPrivateDnsServers().get(0));
        assertEquals(PRIVDNS2, lp.getValidatedPrivateDnsServers().get(1));

        lp.removeValidatedPrivateDnsServer(PRIVDNS1);
        assertEquals(1, lp.getValidatedPrivateDnsServers().size());
        assertEquals(PRIVDNS2, lp.getValidatedPrivateDnsServers().get(0));

        lp.addValidatedPrivateDnsServer(PRIVDNS6);
        assertEquals(2, lp.getValidatedPrivateDnsServers().size());
        assertEquals(PRIVDNS2, lp.getValidatedPrivateDnsServers().get(0));
        assertEquals(PRIVDNS6, lp.getValidatedPrivateDnsServers().get(1));
    }

    @Test
    public void testPcscfServers() {
        final LinkProperties lp = new LinkProperties();
        final List<InetAddress> pcscfServers = Arrays.asList(PCSCFV4);
        lp.setPcscfServers(pcscfServers);
        assertEquals(1, lp.getPcscfServers().size());
        assertEquals(PCSCFV4, lp.getPcscfServers().get(0));

        lp.removePcscfServer(PCSCFV4);
        assertEquals(0, lp.getPcscfServers().size());

        lp.addPcscfServer(PCSCFV6);
        assertEquals(1, lp.getPcscfServers().size());
        assertEquals(PCSCFV6, lp.getPcscfServers().get(0));
    }

    @Test
    public void testTcpBufferSizes() {
        final LinkProperties lp = makeTestObject();
        assertEquals(TCP_BUFFER_SIZES, lp.getTcpBufferSizes());

        lp.setTcpBufferSizes(null);
        assertNull(lp.getTcpBufferSizes());
    }

    @Test
    public void testHasIpv6DefaultRoute() {
        final LinkProperties lp = makeTestObject();
        assertFalse(lp.hasIPv6DefaultRoute());

        lp.addRoute(new RouteInfo(GATEWAY61));
        assertTrue(lp.hasIPv6DefaultRoute());
    }

    @Test
    public void testHttpProxy() {
        final LinkProperties lp = makeTestObject();
        assertTrue(lp.getHttpProxy().equals(ProxyInfo.buildDirectProxy("test", 8888)));
    }

    @Test
    public void testPrivateDnsServerName() {
        final LinkProperties lp = makeTestObject();
        assertEquals(PRIV_DNS_SERVER_NAME, lp.getPrivateDnsServerName());

        lp.setPrivateDnsServerName(null);
        assertNull(lp.getPrivateDnsServerName());
    }

    @Test
    public void testUsePrivateDns() {
        final LinkProperties lp = makeTestObject();
        assertTrue(lp.isPrivateDnsActive());

        lp.clear();
        assertFalse(lp.isPrivateDnsActive());
    }

    @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
    public void testDhcpServerAddress() {
        final LinkProperties lp = makeTestObject();
        assertEquals(DHCPSERVER, lp.getDhcpServerAddress());

        lp.clear();
        assertNull(lp.getDhcpServerAddress());
    }

    @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
    public void testWakeOnLanSupported() {
        final LinkProperties lp = makeTestObject();
        assertTrue(lp.isWakeOnLanSupported());

        lp.clear();
        assertFalse(lp.isWakeOnLanSupported());
    }

    @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
    public void testCaptivePortalApiUrl() {
        final LinkProperties lp = makeTestObject();
        assertEquals(CAPPORT_API_URL, lp.getCaptivePortalApiUrl());

        lp.clear();
        assertNull(lp.getCaptivePortalApiUrl());
    }

    @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
    public void testCaptivePortalData() {
        final LinkProperties lp = makeTestObject();
        assertEquals(getCaptivePortalData(), lp.getCaptivePortalData());

        lp.clear();
        assertNull(lp.getCaptivePortalData());
    }

    private LinkProperties makeIpv4LinkProperties() {
        final LinkProperties linkProperties = new LinkProperties();
        linkProperties.setInterfaceName(NAME);
        linkProperties.addLinkAddress(LINKADDRV4);
        linkProperties.addDnsServer(DNS1);
        linkProperties.addRoute(new RouteInfo(GATEWAY1));
        linkProperties.addRoute(new RouteInfo(GATEWAY2));
        return linkProperties;
    }

    private LinkProperties makeIpv6LinkProperties() {
        final LinkProperties linkProperties = new LinkProperties();
        linkProperties.setInterfaceName(NAME);
        linkProperties.addLinkAddress(LINKADDRV6);
        linkProperties.addDnsServer(DNS6);
        linkProperties.addRoute(new RouteInfo(GATEWAY61));
        linkProperties.addRoute(new RouteInfo(GATEWAY62));
        return linkProperties;
    }

    @Test
    public void testHasIpv4DefaultRoute() {
        final LinkProperties Ipv4 = makeIpv4LinkProperties();
        assertTrue(Ipv4.hasIpv4DefaultRoute());
        final LinkProperties Ipv6 = makeIpv6LinkProperties();
        assertFalse(Ipv6.hasIpv4DefaultRoute());
    }

    @Test
    public void testHasIpv4DnsServer() {
        final LinkProperties Ipv4 = makeIpv4LinkProperties();
        assertTrue(Ipv4.hasIpv4DnsServer());
        final LinkProperties Ipv6 = makeIpv6LinkProperties();
        assertFalse(Ipv6.hasIpv4DnsServer());
    }

    @Test
    public void testHasIpv6DnsServer() {
        final LinkProperties Ipv4 = makeIpv4LinkProperties();
        assertFalse(Ipv4.hasIpv6DnsServer());
        final LinkProperties Ipv6 = makeIpv6LinkProperties();
        assertTrue(Ipv6.hasIpv6DnsServer());
    }

    @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
    public void testHasIpv4UnreachableDefaultRoute() {
        final LinkProperties lp = makeTestObject();
        assertFalse(lp.hasIpv4UnreachableDefaultRoute());
        assertFalse(lp.hasIpv6UnreachableDefaultRoute());

        lp.addRoute(new RouteInfo(new IpPrefix(Inet4Address.ANY, 0), RTN_UNREACHABLE));
        assertTrue(lp.hasIpv4UnreachableDefaultRoute());
        assertFalse(lp.hasIpv6UnreachableDefaultRoute());
    }

    @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
    public void testHasIpv6UnreachableDefaultRoute() {
        final LinkProperties lp = makeTestObject();
        assertFalse(lp.hasIpv6UnreachableDefaultRoute());
        assertFalse(lp.hasIpv4UnreachableDefaultRoute());

        lp.addRoute(new RouteInfo(new IpPrefix(Inet6Address.ANY, 0), RTN_UNREACHABLE));
        assertTrue(lp.hasIpv6UnreachableDefaultRoute());
        assertFalse(lp.hasIpv4UnreachableDefaultRoute());
    }

    @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
    public void testRouteAddWithSameKey() throws Exception {
        LinkProperties lp = new LinkProperties();
        lp.setInterfaceName("wlan0");
        final IpPrefix v6 = new IpPrefix("64:ff9b::/96");
        lp.addRoute(new RouteInfo(v6, address("fe80::1"), "wlan0", RTN_UNICAST, 1280));
        assertEquals(1, lp.getRoutes().size());
        lp.addRoute(new RouteInfo(v6, address("fe80::1"), "wlan0", RTN_UNICAST, 1500));
        assertEquals(1, lp.getRoutes().size());
        final IpPrefix v4 = new IpPrefix("192.0.2.128/25");
        lp.addRoute(new RouteInfo(v4, address("192.0.2.1"), "wlan0", RTN_UNICAST, 1460));
        assertEquals(2, lp.getRoutes().size());
        lp.addRoute(new RouteInfo(v4, address("192.0.2.1"), "wlan0", RTN_THROW, 1460));
        assertEquals(2, lp.getRoutes().size());
    }
}