Use case-insensitive matching in discovery/advertising

mDNS is supposed to be case-insensitive (like DNS). Both advertising and
discovery logic should use case-insensitive matching instead of
case-sensitive matching.

The case sensitive matching can be found by grepping the String.equals()
and Arrays.equals() check across the whole code base. Each occurrence is
analyzed carefully to list up all necessary fixes.

Bug: 272194544
Test: atest FrameworksNetTests
Change-Id: I7c10878129663549c9171c1420b6f399930df2cb

service-t/src/com/android/server/connectivity/mdns/MdnsAdvertiser.java

@@ -253,8 +253,9 @@ public class MdnsAdvertiser {
         int getConflictingService(@NonNull NsdServiceInfo info) {
             for (int i = 0; i < mPendingRegistrations.size(); i++) {
                 final NsdServiceInfo other = mPendingRegistrations.valueAt(i).getServiceInfo();
-                if (info.getServiceName().equals(other.getServiceName())
+                if (MdnsUtils.equalsIgnoreDnsCase(info.getServiceName(), other.getServiceName())
-                        && info.getServiceType().equals(other.getServiceType())) {
+                        && MdnsUtils.equalsIgnoreDnsCase(info.getServiceType(),
+                        other.getServiceType())) {
                     return mPendingRegistrations.keyAt(i);
                 }
             }

service-t/src/com/android/server/connectivity/mdns/MdnsDiscoveryManager.java

@@ -30,6 +30,7 @@ import android.util.Pair;
 import com.android.internal.annotations.GuardedBy;
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.net.module.util.SharedLog;
+import com.android.server.connectivity.mdns.util.MdnsUtils;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -56,21 +57,26 @@ public class MdnsDiscoveryManager implements MdnsSocketClientBase.Callback {
 
         public void put(@NonNull String serviceType, @Nullable Network network,
                 @NonNull MdnsServiceTypeClient client) {
-            final Pair<String, Network> perNetworkServiceType = new Pair<>(serviceType, network);
+            final String dnsLowerServiceType = MdnsUtils.toDnsLowerCase(serviceType);
+            final Pair<String, Network> perNetworkServiceType = new Pair<>(dnsLowerServiceType,
+                    network);
             clients.put(perNetworkServiceType, client);
         }
 
         @Nullable
         public MdnsServiceTypeClient get(@NonNull String serviceType, @Nullable Network network) {
-            final Pair<String, Network> perNetworkServiceType = new Pair<>(serviceType, network);
+            final String dnsLowerServiceType = MdnsUtils.toDnsLowerCase(serviceType);
+            final Pair<String, Network> perNetworkServiceType = new Pair<>(dnsLowerServiceType,
+                    network);
             return clients.getOrDefault(perNetworkServiceType, null);
         }
 
         public List<MdnsServiceTypeClient> getByServiceType(@NonNull String serviceType) {
+            final String dnsLowerServiceType = MdnsUtils.toDnsLowerCase(serviceType);
             final List<MdnsServiceTypeClient> list = new ArrayList<>();
             for (int i = 0; i < clients.size(); i++) {
                 final Pair<String, Network> perNetworkServiceType = clients.keyAt(i);
-                if (serviceType.equals(perNetworkServiceType.first)) {
+                if (dnsLowerServiceType.equals(perNetworkServiceType.first)) {
                     list.add(clients.valueAt(i));
                 }
             }

service-t/src/com/android/server/connectivity/mdns/MdnsNsecRecord.java

@@ -20,6 +20,7 @@ import android.net.DnsResolver;
 import android.text.TextUtils;
 
 import com.android.net.module.util.CollectionUtils;
+import com.android.server.connectivity.mdns.util.MdnsUtils;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -152,7 +153,8 @@ public class MdnsNsecRecord extends MdnsRecord {
     @Override
     public int hashCode() {
         return Objects.hash(super.hashCode(),
-                Arrays.hashCode(mNextDomain), Arrays.hashCode(mTypes));
+                Arrays.hashCode(MdnsUtils.toDnsLabelsLowerCase(mNextDomain)),
+                Arrays.hashCode(mTypes));
     }
 
     @Override
@@ -165,7 +167,8 @@ public class MdnsNsecRecord extends MdnsRecord {
         }
 
         return super.equals(other)
-                && Arrays.equals(mNextDomain, ((MdnsNsecRecord) other).mNextDomain)
+                && MdnsUtils.equalsDnsLabelIgnoreDnsCase(mNextDomain,
+                ((MdnsNsecRecord) other).mNextDomain)
                 && Arrays.equals(mTypes, ((MdnsNsecRecord) other).mTypes);
     }
 }

service-t/src/com/android/server/connectivity/mdns/MdnsPacketWriter.java

@@ -17,11 +17,11 @@
 package com.android.server.connectivity.mdns;
 
 import com.android.server.connectivity.mdns.MdnsServiceInfo.TextEntry;
+import com.android.server.connectivity.mdns.util.MdnsUtils;
 
 import java.io.IOException;
 import java.net.DatagramPacket;
 import java.net.SocketAddress;
-import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -180,7 +180,7 @@ public class MdnsPacketWriter {
             int existingOffset = entry.getKey();
             String[] existingLabels = entry.getValue();
 
-            if (Arrays.equals(existingLabels, labels)) {
+            if (MdnsUtils.equalsDnsLabelIgnoreDnsCase(existingLabels, labels)) {
                 writePointer(existingOffset);
                 return;
             } else if (MdnsRecord.labelsAreSuffix(existingLabels, labels)) {

service-t/src/com/android/server/connectivity/mdns/MdnsPointerRecord.java

@@ -19,6 +19,7 @@ package com.android.server.connectivity.mdns;
 import android.annotation.Nullable;
 
 import com.android.internal.annotations.VisibleForTesting;
+import com.android.server.connectivity.mdns.util.MdnsUtils;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -60,7 +61,8 @@ public class MdnsPointerRecord extends MdnsRecord {
     }
 
     public boolean hasSubtype() {
-        return (name != null) && (name.length > 2) && name[1].equals(MdnsConstants.SUBTYPE_LABEL);
+        return (name != null) && (name.length > 2) && MdnsUtils.equalsIgnoreDnsCase(name[1],
+                MdnsConstants.SUBTYPE_LABEL);
     }
 
     public String getSubtype() {
@@ -74,7 +76,7 @@ public class MdnsPointerRecord extends MdnsRecord {
 
     @Override
     public int hashCode() {
-        return (super.hashCode() * 31) + Arrays.hashCode(pointer);
+        return (super.hashCode() * 31) + Arrays.hashCode(MdnsUtils.toDnsLabelsLowerCase(pointer));
     }
 
     @Override
@@ -86,6 +88,7 @@ public class MdnsPointerRecord extends MdnsRecord {
             return false;
         }
 
-        return super.equals(other) && Arrays.equals(pointer, ((MdnsPointerRecord) other).pointer);
+        return super.equals(other) && MdnsUtils.equalsDnsLabelIgnoreDnsCase(pointer,
+                ((MdnsPointerRecord) other).pointer);
     }
 }

service-t/src/com/android/server/connectivity/mdns/MdnsProber.java

@@ -21,9 +21,9 @@ import android.os.Looper;
 
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.net.module.util.CollectionUtils;
+import com.android.server.connectivity.mdns.util.MdnsUtils;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
@@ -113,7 +113,8 @@ public class MdnsProber extends MdnsPacketRepeater<MdnsProber.ProbingInfo> {
          */
         private static boolean containsName(@NonNull List<MdnsRecord> records,
                 @NonNull String[] name) {
-            return CollectionUtils.any(records, r -> Arrays.equals(name, r.getName()));
+            return CollectionUtils.any(records,
+                    r -> MdnsUtils.equalsDnsLabelIgnoreDnsCase(name, r.getName()));
         }
     }
 

service-t/src/com/android/server/connectivity/mdns/MdnsRecord.java

@@ -24,6 +24,7 @@ import android.os.SystemClock;
 import android.text.TextUtils;
 
 import com.android.internal.annotations.VisibleForTesting;
+import com.android.server.connectivity.mdns.util.MdnsUtils;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -136,7 +137,7 @@ public abstract class MdnsRecord {
         }
 
         for (int i = 0; i < list1.length; ++i) {
-            if (!list1[i].equals(list2[i + offset])) {
+            if (!MdnsUtils.equalsIgnoreDnsCase(list1[i], list2[i + offset])) {
                 return false;
             }
         }
@@ -271,12 +272,13 @@ public abstract class MdnsRecord {
 
         MdnsRecord otherRecord = (MdnsRecord) other;
 
-        return Arrays.equals(name, otherRecord.name) && (type == otherRecord.type);
+        return MdnsUtils.equalsDnsLabelIgnoreDnsCase(name, otherRecord.name) && (type
+                == otherRecord.type);
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(Arrays.hashCode(name), type);
+        return Objects.hash(Arrays.hashCode(MdnsUtils.toDnsLabelsLowerCase(name)), type);
     }
 
     /**
@@ -297,7 +299,7 @@ public abstract class MdnsRecord {
 
         public Key(int recordType, String[] recordName) {
             this.recordType = recordType;
-            this.recordName = recordName;
+            this.recordName = MdnsUtils.toDnsLabelsLowerCase(recordName);
         }
 
         @Override

service-t/src/com/android/server/connectivity/mdns/MdnsRecordRepository.java

@@ -30,6 +30,7 @@ import android.util.SparseArray;
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.net.module.util.CollectionUtils;
 import com.android.net.module.util.HexDump;
+import com.android.server.connectivity.mdns.util.MdnsUtils;
 
 import java.io.IOException;
 import java.net.Inet4Address;
@@ -329,7 +330,8 @@ public class MdnsRecordRepository {
     private int getServiceByName(@NonNull String serviceName) {
         for (int i = 0; i < mServices.size(); i++) {
             final ServiceRegistration registration = mServices.valueAt(i);
-            if (serviceName.equals(registration.serviceInfo.getServiceName())) {
+            if (MdnsUtils.equalsIgnoreDnsCase(serviceName,
+                    registration.serviceInfo.getServiceName())) {
                 return mServices.keyAt(i);
             }
         }
@@ -545,7 +547,9 @@ public class MdnsRecordRepository {
              must match the question qtype unless the qtype is "ANY" (255) or the rrtype is
              "CNAME" (5), and the record rrclass must match the question qclass unless the
              qclass is "ANY" (255) */
-            if (!Arrays.equals(info.record.getName(), question.getName())) continue;
+            if (!MdnsUtils.equalsDnsLabelIgnoreDnsCase(info.record.getName(), question.getName())) {
+                continue;
+            }
             hasFullyOwnedNameMatch |= !info.isSharedName;
 
             // The repository does not store CNAME records
@@ -747,7 +751,10 @@ public class MdnsRecordRepository {
                 // happens. In fact probing is only done for the service name in the SRV record.
                 // This means only SRV and TXT records need to be checked.
                 final RecordInfo<MdnsServiceRecord> srvRecord = registration.srvRecord;
-                if (!Arrays.equals(record.getName(), srvRecord.record.getName())) continue;
+                if (!MdnsUtils.equalsDnsLabelIgnoreDnsCase(record.getName(),
+                        srvRecord.record.getName())) {
+                    continue;
+                }
 
                 // As per RFC6762 9., it's fine if the "conflict" is an identical record with same
                 // data.

service-t/src/com/android/server/connectivity/mdns/MdnsResponse.java

@@ -21,10 +21,10 @@ import android.annotation.Nullable;
 import android.net.Network;
 
 import com.android.internal.annotations.VisibleForTesting;
+import com.android.server.connectivity.mdns.util.MdnsUtils;
 
 import java.io.IOException;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.LinkedList;
@@ -103,7 +103,7 @@ public class MdnsResponse {
      * pointer record is already present in the response with the same TTL.
      */
     public synchronized boolean addPointerRecord(MdnsPointerRecord pointerRecord) {
-        if (!Arrays.equals(serviceName, pointerRecord.getPointer())) {
+        if (!MdnsUtils.equalsDnsLabelIgnoreDnsCase(serviceName, pointerRecord.getPointer())) {
             throw new IllegalArgumentException(
                     "Pointer records for different service names cannot be added");
         }
@@ -301,13 +301,13 @@ public class MdnsResponse {
         boolean dropAddressRecords = false;
 
         for (MdnsInetAddressRecord inetAddressRecord : getInet4AddressRecords()) {
-            if (!Arrays.equals(
+            if (!MdnsUtils.equalsDnsLabelIgnoreDnsCase(
                     this.serviceRecord.getServiceHost(), inetAddressRecord.getName())) {
                 dropAddressRecords = true;
             }
         }
         for (MdnsInetAddressRecord inetAddressRecord : getInet6AddressRecords()) {
-            if (!Arrays.equals(
+            if (!MdnsUtils.equalsDnsLabelIgnoreDnsCase(
                     this.serviceRecord.getServiceHost(), inetAddressRecord.getName())) {
                 dropAddressRecords = true;
             }

service-t/src/com/android/server/connectivity/mdns/MdnsResponseDecoder.java

@@ -23,10 +23,10 @@ import android.os.SystemClock;
 import android.util.ArraySet;
 
 import com.android.server.connectivity.mdns.util.MdnsLogger;
+import com.android.server.connectivity.mdns.util.MdnsUtils;
 
 import java.io.EOFException;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 
@@ -50,7 +50,7 @@ public class MdnsResponseDecoder {
             List<MdnsResponse> responses, String[] pointer) {
         if (responses != null) {
             for (MdnsResponse response : responses) {
-                if (Arrays.equals(response.getServiceName(), pointer)) {
+                if (MdnsUtils.equalsDnsLabelIgnoreDnsCase(response.getServiceName(), pointer)) {
                     return response;
                 }
             }
@@ -66,7 +66,8 @@ public class MdnsResponseDecoder {
                 if (serviceRecord == null) {
                     continue;
                 }
-                if (Arrays.equals(serviceRecord.getServiceHost(), hostName)) {
+                if (MdnsUtils.equalsDnsLabelIgnoreDnsCase(serviceRecord.getServiceHost(),
+                        hostName)) {
                     return response;
                 }
             }
@@ -164,11 +165,8 @@ public class MdnsResponseDecoder {
         for (MdnsRecord record : records) {
             if (record instanceof MdnsPointerRecord) {
                 String[] name = record.getName();
-                if ((serviceType == null)
+                if ((serviceType == null) || MdnsUtils.typeEqualsOrIsSubtype(
-                        || Arrays.equals(name, serviceType)
+                        serviceType, name)) {
-                        || ((name.length == (serviceType.length + 2))
-                        && name[1].equals(MdnsConstants.SUBTYPE_LABEL)
-                        && MdnsRecord.labelsAreSuffix(serviceType, name))) {
                     MdnsPointerRecord pointerRecord = (MdnsPointerRecord) record;
                     // Group PTR records that refer to the same service instance name into a single
                     // response.
@@ -296,7 +294,7 @@ public class MdnsResponseDecoder {
             if (serviceRecord == null) {
                 continue;
             }
-            if (Arrays.equals(serviceRecord.getServiceHost(), hostName)) {
+            if (MdnsUtils.equalsDnsLabelIgnoreDnsCase(serviceRecord.getServiceHost(), hostName)) {
                 if (result == null) {
                     result = new ArrayList<>(/* initialCapacity= */ responses.size());
                 }

service-t/src/com/android/server/connectivity/mdns/MdnsServiceRecord.java

@@ -19,6 +19,7 @@ package com.android.server.connectivity.mdns;
 import android.annotation.Nullable;
 
 import com.android.internal.annotations.VisibleForTesting;
+import com.android.server.connectivity.mdns.util.MdnsUtils;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -142,7 +143,8 @@ public class MdnsServiceRecord extends MdnsRecord {
     @Override
     public int hashCode() {
         return (super.hashCode() * 31)
-                + Objects.hash(servicePriority, serviceWeight, Arrays.hashCode(serviceHost),
+                + Objects.hash(servicePriority, serviceWeight,
+                Arrays.hashCode(MdnsUtils.toDnsLabelsLowerCase(serviceHost)),
                 servicePort);
     }
 
@@ -159,7 +161,7 @@ public class MdnsServiceRecord extends MdnsRecord {
         return super.equals(other)
                 && (servicePriority == otherRecord.servicePriority)
                 && (serviceWeight == otherRecord.serviceWeight)
-                && Arrays.equals(serviceHost, otherRecord.serviceHost)
+                && MdnsUtils.equalsDnsLabelIgnoreDnsCase(serviceHost, otherRecord.serviceHost)
                 && (servicePort == otherRecord.servicePort);
     }
 }

service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java

@@ -21,6 +21,9 @@ import android.annotation.Nullable;
 import android.net.Network;
 import android.os.Handler;
 
+import com.android.server.connectivity.mdns.MdnsConstants;
+import com.android.server.connectivity.mdns.MdnsRecord;
+
 import java.nio.ByteBuffer;
 import java.nio.CharBuffer;
 import java.nio.charset.Charset;
@@ -49,6 +52,17 @@ public class MdnsUtils {
         return new String(outChars);
     }
 
+    /**
+     * Convert the array of labels to DNS case-insensitive lowercase.
+     */
+    public static String[] toDnsLabelsLowerCase(@NonNull String[] labels) {
+        final String[] outStrings = new String[labels.length];
+        for (int i = 0; i < labels.length; ++i) {
+            outStrings[i] = toDnsLowerCase(labels[i]);
+        }
+        return outStrings;
+    }
+
     /**
      * Compare two strings by DNS case-insensitive lowercase.
      */
@@ -62,6 +76,39 @@ public class MdnsUtils {
         return true;
     }
 
+    /**
+     * Compare two set of DNS labels by DNS case-insensitive lowercase.
+     */
+    public static boolean equalsDnsLabelIgnoreDnsCase(@NonNull String[] a, @NonNull String[] b) {
+        if (a == b) {
+            return true;
+        }
+        int length = a.length;
+        if (b.length != length) {
+            return false;
+        }
+        for (int i = 0; i < length; i++) {
+            if (!equalsIgnoreDnsCase(a[i], b[i])) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Compare labels a equals b or a is suffix of b.
+     *
+     * @param a the type or subtype.
+     * @param b the base type
+     */
+    public static boolean typeEqualsOrIsSubtype(@NonNull String[] a,
+            @NonNull String[] b) {
+        return MdnsUtils.equalsDnsLabelIgnoreDnsCase(a, b)
+                || ((b.length == (a.length + 2))
+                && MdnsUtils.equalsIgnoreDnsCase(b[1], MdnsConstants.SUBTYPE_LABEL)
+                && MdnsRecord.labelsAreSuffix(a, b));
+    }
+
     private static char toDnsLowerCase(char a) {
         return a >= 'A' && a <= 'Z' ? (char) (a + ('a' - 'A')) : a;
     }

tests/unit/java/com/android/server/connectivity/mdns/MdnsAdvertiserTest.kt

@@ -51,6 +51,7 @@ private const val SERVICE_ID_1 = 1
 private const val SERVICE_ID_2 = 2
 private const val LONG_SERVICE_ID_1 = 3
 private const val LONG_SERVICE_ID_2 = 4
+private const val CASE_INSENSITIVE_TEST_SERVICE_ID = 5
 private const val TIMEOUT_MS = 10_000L
 private val TEST_ADDR = parseNumericAddress("2001:db8::123")
 private val TEST_LINKADDR = LinkAddress(TEST_ADDR, 64 /* prefixLength */)
@@ -78,6 +79,13 @@ private val ALL_NETWORKS_SERVICE = NsdServiceInfo("TestServiceName", "_advertise
     network = null
 }
 
+private val ALL_NETWORKS_SERVICE_2 =
+    NsdServiceInfo("TESTSERVICENAME", "_ADVERTISERTEST._tcp").apply {
+        port = 12345
+        hostAddresses = listOf(TEST_ADDR)
+        network = null
+    }
+
 private val LONG_ALL_NETWORKS_SERVICE =
     NsdServiceInfo("a".repeat(48) + "TestServiceName", "_longadvertisertest._tcp").apply {
         port = 12345
@@ -228,6 +236,9 @@ class MdnsAdvertiserTest {
         postSync { advertiser.addService(LONG_SERVICE_ID_2, LONG_ALL_NETWORKS_SERVICE,
                 null /* subtype */) }
 
+        postSync { advertiser.addService(CASE_INSENSITIVE_TEST_SERVICE_ID, ALL_NETWORKS_SERVICE_2,
+                null /* subtype */) }
+
         // Callbacks for matching network and all networks both get the socket
         postSync {
             oneNetSocketCb.onSocketCreated(TEST_NETWORK_1, mockSocket1, listOf(TEST_LINKADDR))
@@ -249,6 +260,14 @@ class MdnsAdvertiserTest {
             network = LONG_ALL_NETWORKS_SERVICE.network
         }
 
+        val expectedCaseInsensitiveRenamed = NsdServiceInfo(
+            "${ALL_NETWORKS_SERVICE_2.serviceName} (3)", ALL_NETWORKS_SERVICE_2.serviceType
+        ).apply {
+            port = ALL_NETWORKS_SERVICE_2.port
+            hostAddresses = ALL_NETWORKS_SERVICE_2.hostAddresses
+            network = ALL_NETWORKS_SERVICE_2.network
+        }
+
         val intAdvCbCaptor = ArgumentCaptor.forClass(MdnsInterfaceAdvertiser.Callback::class.java)
         verify(mockDeps).makeAdvertiser(eq(mockSocket1), eq(listOf(TEST_LINKADDR)),
                 eq(thread.looper), any(), intAdvCbCaptor.capture(), eq(TEST_HOSTNAME), any()
@@ -261,6 +280,8 @@ class MdnsAdvertiserTest {
                 argThat { it.matches(LONG_SERVICE_1) }, eq(null))
         verify(mockInterfaceAdvertiser1).addService(eq(LONG_SERVICE_ID_2),
             argThat { it.matches(expectedLongRenamed) }, eq(null))
+        verify(mockInterfaceAdvertiser1).addService(eq(CASE_INSENSITIVE_TEST_SERVICE_ID),
+            argThat { it.matches(expectedCaseInsensitiveRenamed) }, eq(null))
 
         doReturn(false).`when`(mockInterfaceAdvertiser1).isProbing(SERVICE_ID_1)
         postSync { intAdvCbCaptor.value.onRegisterServiceSucceeded(

tests/unit/java/com/android/server/connectivity/mdns/MdnsPacketWriterTest.kt

@@ -31,7 +31,7 @@ class MdnsPacketWriterTest {
     @Test
     fun testNameCompression() {
         val writer = MdnsPacketWriter(ByteArray(1000))
-        writer.writeLabels(arrayOf("my", "first", "name"))
+        writer.writeLabels(arrayOf("my", "FIRST", "name"))
         writer.writeLabels(arrayOf("my", "second", "name"))
         writer.writeLabels(arrayOf("other", "first", "name"))
         writer.writeLabels(arrayOf("my", "second", "name"))
@@ -41,7 +41,7 @@ class MdnsPacketWriterTest {
                 InetSocketAddress(InetAddresses.parseNumericAddress("2001:db8::123"), 123))
 
         // Each label takes length + 1. So "first.name" offset = 3, "name" offset = 9
-        val expected = "my".label() + "first".label() + "name".label() + 0x00.toByte() +
+        val expected = "my".label() + "FIRST".label() + "name".label() + 0x00.toByte() +
                 // "my.second.name" offset = 15
                 "my".label() + "second".label() + byteArrayOf(0xC0.toByte(), 9) +
                 "other".label() + byteArrayOf(0xC0.toByte(), 3) +

tests/unit/java/com/android/server/connectivity/mdns/MdnsProberTest.kt

@@ -48,6 +48,7 @@ private const val SHORT_TIMEOUT_MS = 200L
 
 private val TEST_SERVICE_NAME_1 = arrayOf("testservice", "_nmt", "_tcp", "local")
 private val TEST_SERVICE_NAME_2 = arrayOf("testservice2", "_nmt", "_tcp", "local")
+private val TEST_SERVICE_NAME_3 = arrayOf("Testservice", "_nmt", "_tcp", "local")
 
 @RunWith(DevSdkIgnoreRunner::class)
 @IgnoreUpTo(Build.VERSION_CODES.S_V2)
@@ -128,6 +129,15 @@ class MdnsProberTest {
         assertProbesSent(probeInfo, expected)
     }
 
+    @Test
+    fun testCreateProberCaseInsensitive() {
+        val probeInfo = TestProbeInfo(
+            listOf(makeServiceRecord(TEST_SERVICE_NAME_1, 37890),
+                makeServiceRecord(TEST_SERVICE_NAME_2, 37890),
+                makeServiceRecord(TEST_SERVICE_NAME_3, 37890)))
+        assertEquals(2, probeInfo.getPacket(0).questions.size)
+    }
+
     @Test
     fun testProbeMultipleRecords() {
         val replySender = MdnsReplySender("testiface", thread.looper, socket, buffer)

tests/unit/java/com/android/server/connectivity/mdns/MdnsRecordRepositoryTest.kt

@@ -43,6 +43,7 @@ import org.junit.runner.RunWith
 
 private const val TEST_SERVICE_ID_1 = 42
 private const val TEST_SERVICE_ID_2 = 43
+private const val TEST_SERVICE_ID_3 = 44
 private const val TEST_PORT = 12345
 private const val TEST_SUBTYPE = "_subtype"
 private val TEST_HOSTNAME = arrayOf("Android_000102030405060708090A0B0C0D0E0F", "local")
@@ -63,6 +64,12 @@ private val TEST_SERVICE_2 = NsdServiceInfo().apply {
     port = TEST_PORT
 }
 
+private val TEST_SERVICE_3 = NsdServiceInfo().apply {
+    serviceType = "_TESTSERVICE._tcp"
+    serviceName = "MyTESTSERVICE"
+    port = TEST_PORT
+}
+
 @RunWith(DevSdkIgnoreRunner::class)
 @DevSdkIgnoreRule.IgnoreUpTo(Build.VERSION_CODES.S_V2)
 class MdnsRecordRepositoryTest {
@@ -124,6 +131,9 @@ class MdnsRecordRepositoryTest {
         assertFailsWith(NameConflictException::class) {
             repository.addService(TEST_SERVICE_ID_2, TEST_SERVICE_1, null /* subtype */)
         }
+        assertFailsWith(NameConflictException::class) {
+            repository.addService(TEST_SERVICE_ID_3, TEST_SERVICE_3, null /* subtype */)
+        }
     }
 
     @Test
@@ -364,6 +374,27 @@ class MdnsRecordRepositoryTest {
         assertContentEquals(expectedV4, getReverseDnsAddress(parseNumericAddress("192.0.2.123")))
     }
 
+    @Test
+    fun testGetReplyCaseInsensitive() {
+        val repository = MdnsRecordRepository(thread.looper, deps, TEST_HOSTNAME)
+        repository.initWithService(TEST_SERVICE_ID_1, TEST_SERVICE_1)
+        val questionsCaseInSensitive =
+            listOf(MdnsPointerRecord(arrayOf("_TESTSERVICE", "_TCP", "local"),
+                0L /* receiptTimeMillis */,
+                false /* cacheFlush */,
+                // TTL and data is empty for a question
+                0L /* ttlMillis */,
+                null /* pointer */))
+        val queryCaseInsensitive = MdnsPacket(0 /* flags */, questionsCaseInSensitive,
+            listOf() /* answers */, listOf() /* authorityRecords */,
+            listOf() /* additionalRecords */)
+        val src = InetSocketAddress(parseNumericAddress("192.0.2.123"), 5353)
+        val replyCaseInsensitive = repository.getReply(queryCaseInsensitive, src)
+        assertNotNull(replyCaseInsensitive)
+        assertEquals(1, replyCaseInsensitive.answers.size)
+        assertEquals(7, replyCaseInsensitive.additionalAnswers.size)
+    }
+
     @Test
     fun testGetReply() {
         doGetReplyTest(subtype = null)
@@ -489,6 +520,34 @@ class MdnsRecordRepositoryTest {
                 repository.getConflictingServices(packet))
     }
 
+    @Test
+    fun testGetConflictingServicesCaseInsensitive() {
+        val repository = MdnsRecordRepository(thread.looper, deps, TEST_HOSTNAME)
+        repository.addService(TEST_SERVICE_ID_1, TEST_SERVICE_1, null /* subtype */)
+        repository.addService(TEST_SERVICE_ID_2, TEST_SERVICE_2, null /* subtype */)
+
+        val packet = MdnsPacket(
+            0 /* flags */,
+            emptyList() /* questions */,
+            listOf(
+                MdnsServiceRecord(
+                    arrayOf("MYTESTSERVICE", "_TESTSERVICE", "_tcp", "local"),
+                    0L /* receiptTimeMillis */, true /* cacheFlush */, 0L /* ttlMillis */,
+                    0 /* servicePriority */, 0 /* serviceWeight */,
+                    TEST_SERVICE_1.port + 1,
+                    TEST_HOSTNAME),
+                MdnsTextRecord(
+                    arrayOf("MYOTHERTESTSERVICE", "_TESTSERVICE", "_tcp", "local"),
+                    0L /* receiptTimeMillis */, true /* cacheFlush */, 0L /* ttlMillis */,
+                    listOf(TextEntry.fromString("somedifferent=entry"))),
+            ) /* answers */,
+            emptyList() /* authorityRecords */,
+            emptyList() /* additionalRecords */)
+
+        assertEquals(setOf(TEST_SERVICE_ID_1, TEST_SERVICE_ID_2),
+            repository.getConflictingServices(packet))
+    }
+
     @Test
     fun testGetConflictingServices_IdenticalService() {
         val repository = MdnsRecordRepository(thread.looper, deps, TEST_HOSTNAME)
@@ -505,7 +564,7 @@ class MdnsRecordRepositoryTest {
                                 0L /* receiptTimeMillis */, true /* cacheFlush */,
                                 otherTtlMillis, 0 /* servicePriority */, 0 /* serviceWeight */,
                                 TEST_SERVICE_1.port,
-                                TEST_HOSTNAME),
+                                arrayOf("ANDROID_000102030405060708090A0B0C0D0E0F", "local")),
                         MdnsTextRecord(
                                 arrayOf("MyOtherTestService", "_testservice", "_tcp", "local"),
                                 0L /* receiptTimeMillis */, true /* cacheFlush */,
@@ -517,6 +576,35 @@ class MdnsRecordRepositoryTest {
         // Above records are identical to the actual registrations: no conflict
         assertEquals(emptySet(), repository.getConflictingServices(packet))
     }
+
+    @Test
+    fun testGetConflictingServicesCaseInsensitive_IdenticalService() {
+        val repository = MdnsRecordRepository(thread.looper, deps, TEST_HOSTNAME)
+        repository.addService(TEST_SERVICE_ID_1, TEST_SERVICE_1, null /* subtype */)
+        repository.addService(TEST_SERVICE_ID_2, TEST_SERVICE_2, null /* subtype */)
+
+        val otherTtlMillis = 1234L
+        val packet = MdnsPacket(
+                0 /* flags */,
+                emptyList() /* questions */,
+                listOf(
+                        MdnsServiceRecord(
+                                arrayOf("MYTESTSERVICE", "_TESTSERVICE", "_tcp", "local"),
+                                0L /* receiptTimeMillis */, true /* cacheFlush */,
+                                otherTtlMillis, 0 /* servicePriority */, 0 /* serviceWeight */,
+                                TEST_SERVICE_1.port,
+                                TEST_HOSTNAME),
+                        MdnsTextRecord(
+                                arrayOf("MyOtherTestService", "_TESTSERVICE", "_tcp", "local"),
+                                0L /* receiptTimeMillis */, true /* cacheFlush */,
+                                otherTtlMillis, emptyList()),
+                ) /* answers */,
+                emptyList() /* authorityRecords */,
+                emptyList() /* additionalRecords */)
+
+        // Above records are identical to the actual registrations: no conflict
+        assertEquals(emptySet(), repository.getConflictingServices(packet))
+    }
 }
 
 private fun MdnsRecordRepository.initWithService(

tests/unit/java/com/android/server/connectivity/mdns/MdnsRecordTest.kt

@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2023 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 com.android.server.connectivity.mdns
+
+import android.os.Build
+import com.android.testutils.DevSdkIgnoreRule
+import com.android.testutils.DevSdkIgnoreRunner
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(DevSdkIgnoreRunner::class)
+@DevSdkIgnoreRule.IgnoreUpTo(Build.VERSION_CODES.S_V2)
+class MdnsRecordTest {
+
+    @Test
+    fun testPointerRecordHasSubType() {
+        val ptrRecord1 = MdnsPointerRecord(
+            arrayOf("_testtype", "_sub", "_tcp", "local"),
+            0L /* receiptTimeMillis */,
+            false /* cacheFlush */,
+            4500000 /* ttlMillis */,
+            arrayOf("testservice", "_testtype", "_tcp", "local")
+        )
+        val ptrRecord2 = MdnsPointerRecord(
+            arrayOf("_testtype", "_SUB", "_tcp", "local"),
+            0L /* receiptTimeMillis */,
+            false /* cacheFlush */,
+            4500000 /* ttlMillis */,
+            arrayOf("testservice", "_testtype", "_tcp", "local")
+        )
+        assertTrue(ptrRecord1.hasSubtype())
+        assertTrue(ptrRecord2.hasSubtype())
+    }
+
+    @Test
+    fun testEqualsCaseInsensitive() {
+        val ptrRecord1 = MdnsPointerRecord(
+            arrayOf("_testtype", "_tcp", "local"),
+            0L /* receiptTimeMillis */,
+            false /* cacheFlush */,
+            4500000 /* ttlMillis */,
+            arrayOf("testservice", "_testtype", "_tcp", "local")
+            )
+        val ptrRecord2 = MdnsPointerRecord(
+            arrayOf("_testType", "_tcp", "local"),
+            0L /* receiptTimeMillis */,
+            false /* cacheFlush */,
+            4500000 /* ttlMillis */,
+            arrayOf("testsErvice", "_testtype", "_Tcp", "local")
+        )
+        assertEquals(ptrRecord1, ptrRecord2)
+        assertEquals(ptrRecord1.hashCode(), ptrRecord2.hashCode())
+
+        val srvRecord1 = MdnsServiceRecord(
+            arrayOf("testservice", "_testtype", "_tcp", "local"),
+            123 /* receiptTimeMillis */,
+            false /* cacheFlush */,
+            2000 /* ttlMillis */,
+            0 /* servicePriority */,
+            0 /* serviceWeight */,
+            80 /* port */,
+            arrayOf("hostname")
+        )
+        val srvRecord2 = MdnsServiceRecord(
+            arrayOf("Testservice", "_testtype", "_tcp", "local"),
+            123 /* receiptTimeMillis */,
+            false /* cacheFlush */,
+            2000 /* ttlMillis */,
+            0 /* servicePriority */,
+            0 /* serviceWeight */,
+            80 /* port */,
+            arrayOf("Hostname")
+        )
+        assertEquals(srvRecord1, srvRecord2)
+        assertEquals(srvRecord1.hashCode(), srvRecord2.hashCode())
+
+        val nsecRecord1 = MdnsNsecRecord(
+            arrayOf("hostname"),
+            0L /* receiptTimeMillis */,
+            true /* cacheFlush */,
+            2000L, /* ttlMillis */
+            arrayOf("hostname"),
+            intArrayOf(1, 2, 3) /* types */
+        )
+        val nsecRecord2 = MdnsNsecRecord(
+            arrayOf("HOSTNAME"),
+            0L /* receiptTimeMillis */,
+            true /* cacheFlush */,
+            2000L, /* ttlMillis */
+            arrayOf("HOSTNAME"),
+            intArrayOf(1, 2, 3) /* types */
+        )
+        assertEquals(nsecRecord1, nsecRecord2)
+        assertEquals(nsecRecord1.hashCode(), nsecRecord2.hashCode())
+    }
+
+    @Test
+    fun testLabelsAreSuffix() {
+        val labels1 = arrayOf("a", "b", "c")
+        val labels2 = arrayOf("B", "C")
+        val labels3 = arrayOf("b", "c")
+        val labels4 = arrayOf("b", "d")
+        assertTrue(MdnsRecord.labelsAreSuffix(labels2, labels1))
+        assertTrue(MdnsRecord.labelsAreSuffix(labels3, labels1))
+        assertFalse(MdnsRecord.labelsAreSuffix(labels4, labels1))
+    }
+}

tests/unit/java/com/android/server/connectivity/mdns/MdnsResponseDecoderTests.java

@@ -269,14 +269,9 @@ public class MdnsResponseDecoderTests {
         assertEquals("st=0", textStrings.get(6));
     }
 
-    @Test
+    private void verifyResponse(ArraySet<MdnsResponse> responseArraySet) {
-    public void testDecodeIPv6AnswerPacket() throws IOException {
+        assertEquals(1, responseArraySet.size());
-        MdnsResponseDecoder decoder = new MdnsResponseDecoder(mClock, CAST_SERVICE_TYPE);
+        MdnsResponse response = responseArraySet.valueAt(0);
-        assertNotNull(data6);
-
-        responses = decode(decoder, data6);
-        assertEquals(1, responses.size());
-        MdnsResponse response = responses.valueAt(0);
         assertTrue(response.isComplete());
 
         MdnsInetAddressRecord inet6AddressRecord = response.getInet6AddressRecord();
@@ -289,6 +284,22 @@ public class MdnsResponseDecoderTests {
         assertEquals(inet6Addr.getHostAddress(), "2000:3333::da6c:63ff:fe7c:7483");
     }
 
+    @Test
+    public void testDecodeIPv6AnswerPacket() throws IOException {
+        MdnsResponseDecoder decoder = new MdnsResponseDecoder(mClock, CAST_SERVICE_TYPE);
+        assertNotNull(data6);
+        verifyResponse(decode(decoder, data6));
+    }
+
+    @Test
+    public void testDecodeCaseInsensitiveMatch() throws IOException {
+        final String[] castServiceTypeUpperCase =
+                new String[] {"_GOOGLECAST", "_TCP", "LOCAL"};
+        MdnsResponseDecoder decoder = new MdnsResponseDecoder(mClock, castServiceTypeUpperCase);
+        assertNotNull(data6);
+        verifyResponse(decode(decoder, data6));
+    }
+
     @Test
     public void testIsComplete() {
         MdnsResponse response = new MdnsResponse(responses.valueAt(0));

tests/unit/java/com/android/server/connectivity/mdns/MdnsResponseTests.java

@@ -228,6 +228,12 @@ public class MdnsResponseTests {
         final MdnsResponse response = makeCompleteResponse(TEST_TTL_MS);
 
         assertFalse(response.addPointerRecord(response.getPointerRecords().get(0)));
+        final String[] serviceName = new String[] { "MYSERVICE", "_TYPE", "_tcp", "local" };
+        final String[] serviceType = new String[] { "_TYPE", "_tcp", "local" };
+        MdnsPointerRecord pointerRecordCaseInsensitive =
+                new MdnsPointerRecord(serviceType, 0L /* receiptTimeMillis */,
+                        false /* cacheFlush */, TEST_TTL_MS, serviceName);
+        assertFalse(response.addPointerRecord(pointerRecordCaseInsensitive));
         assertFalse(response.addInet6AddressRecord(response.getInet6AddressRecord()));
         assertFalse(response.addInet4AddressRecord(response.getInet4AddressRecord()));
         assertFalse(response.setServiceRecord(response.getServiceRecord()));
@@ -270,4 +276,30 @@ public class MdnsResponseTests {
         // All records were replaced, not added
         assertEquals(ttlZeroResponse.getRecords().size(), response.getRecords().size());
     }
+
+    @Test
+    public void dropUnmatchedAddressRecords_caseInsensitive() {
+
+        final String[] hostname = new String[] { "MyHostname" };
+        final String[] upperCaseHostName = new String[] { "MYHOSTNAME" };
+        final String[] serviceName = new String[] { "MyService", "_type", "_tcp", "local" };
+        final String[] serviceType = new String[] { "_type", "_tcp", "local" };
+        final MdnsResponse response = new MdnsResponse(/* now= */ 0, serviceName, INTERFACE_INDEX,
+                mNetwork);
+        response.addPointerRecord(new MdnsPointerRecord(serviceType, 0L /* receiptTimeMillis */,
+                false /* cacheFlush */, TEST_TTL_MS, serviceName));
+        response.setServiceRecord(new MdnsServiceRecord(serviceName, 0L /* receiptTimeMillis */,
+                true /* cacheFlush */, TEST_TTL_MS, 0 /* servicePriority */,
+                0 /* serviceWeight */, 0 /* servicePort */, hostname));
+        response.setTextRecord(new MdnsTextRecord(serviceName, 0L /* receiptTimeMillis */,
+                true /* cacheFlush */, TEST_TTL_MS, emptyList() /* entries */));
+        response.addInet4AddressRecord(new MdnsInetAddressRecord(
+                upperCaseHostName , 0L /* receiptTimeMillis */, true /* cacheFlush */,
+                TEST_TTL_MS, parseNumericAddress("192.0.2.123")));
+        response.addInet6AddressRecord(new MdnsInetAddressRecord(
+                upperCaseHostName, 0L /* receiptTimeMillis */, true /* cacheFlush */,
+                TEST_TTL_MS, parseNumericAddress("2001:db8::123")));
+
+        assertFalse(response.dropUnmatchedAddressRecords());
+    }
 }

tests/unit/java/com/android/server/connectivity/mdns/MdnsServiceTypeClientTests.java

@@ -1006,10 +1006,11 @@ public class MdnsServiceTypeClientTests {
         final String otherInstance = "instance2";
         final String ipV4Address = "192.0.2.0";
         final String ipV6Address = "2001:db8::";
+        final String capitalizedRequestInstance = "Instance1";
 
         final MdnsSearchOptions resolveOptions = MdnsSearchOptions.newBuilder()
                 // Use different case in the options
-                .setResolveInstanceName("Instance1").build();
+                .setResolveInstanceName(capitalizedRequestInstance).build();
 
         client.startSendAndReceive(mockListenerOne, resolveOptions);
         client.startSendAndReceive(mockListenerTwo, MdnsSearchOptions.getDefaultOptions());
@@ -1037,8 +1038,9 @@ public class MdnsServiceTypeClientTests {
                 Collections.emptyMap(), 0L /* ttl */), INTERFACE_INDEX, mockNetwork);
 
         // mockListenerOne gets notified for the requested instance
-        verify(mockListenerOne).onServiceNameDiscovered(matchServiceName(requestedInstance));
+        verify(mockListenerOne).onServiceNameDiscovered(
-        verify(mockListenerOne).onServiceFound(matchServiceName(requestedInstance));
+                matchServiceName(capitalizedRequestInstance));
+        verify(mockListenerOne).onServiceFound(matchServiceName(capitalizedRequestInstance));
 
         // ...but does not get any callback for the other instance
         verify(mockListenerOne, never()).onServiceFound(matchServiceName(otherInstance));
@@ -1049,8 +1051,9 @@ public class MdnsServiceTypeClientTests {
         // mockListenerTwo gets notified for both though
         final InOrder inOrder = inOrder(mockListenerTwo);
         inOrder.verify(mockListenerTwo).onServiceNameDiscovered(
-                matchServiceName(requestedInstance));
+                matchServiceName(capitalizedRequestInstance));
-        inOrder.verify(mockListenerTwo).onServiceFound(matchServiceName(requestedInstance));
+        inOrder.verify(mockListenerTwo).onServiceFound(
+                matchServiceName(capitalizedRequestInstance));
 
         inOrder.verify(mockListenerTwo).onServiceNameDiscovered(matchServiceName(otherInstance));
         inOrder.verify(mockListenerTwo).onServiceFound(matchServiceName(otherInstance));
@@ -1149,8 +1152,7 @@ public class MdnsServiceTypeClientTests {
         final String ipV4Address = "192.0.2.0";
 
         final MdnsSearchOptions resolveOptions = MdnsSearchOptions.newBuilder()
-                // Use different case in the options
+                .setResolveInstanceName("instance1").build();
-                .setResolveInstanceName("Instance1").build();
 
         client.startSendAndReceive(mockListenerOne, resolveOptions);
         client.startSendAndReceive(mockListenerTwo, MdnsSearchOptions.getDefaultOptions());

tests/unit/java/com/android/server/connectivity/mdns/util/MdnsUtilsTest.kt

@@ -17,11 +17,14 @@
 package com.android.server.connectivity.mdns.util
 
 import android.os.Build
+import com.android.server.connectivity.mdns.util.MdnsUtils.equalsDnsLabelIgnoreDnsCase
 import com.android.server.connectivity.mdns.util.MdnsUtils.equalsIgnoreDnsCase
+import com.android.server.connectivity.mdns.util.MdnsUtils.toDnsLabelsLowerCase
 import com.android.server.connectivity.mdns.util.MdnsUtils.toDnsLowerCase
 import com.android.server.connectivity.mdns.util.MdnsUtils.truncateServiceName
 import com.android.testutils.DevSdkIgnoreRule
 import com.android.testutils.DevSdkIgnoreRunner
+import org.junit.Assert.assertArrayEquals
 import org.junit.Assert.assertEquals
 import org.junit.Assert.assertFalse
 import org.junit.Assert.assertTrue
@@ -49,6 +52,12 @@ class MdnsUtilsTest {
                         "\udc77\udb40\udc6c\udb40\udc73\udb40\udc7f<"))
     }
 
+    @Test
+    fun testToDnsLabelsLowerCase() {
+        assertArrayEquals(arrayOf("test", "tÉst", "ţést"),
+            toDnsLabelsLowerCase(arrayOf("TeSt", "TÉST", "ţést")))
+    }
+
     @Test
     fun testEqualsIgnoreDnsCase() {
         assertTrue(equalsIgnoreDnsCase("TEST", "Test"))
@@ -72,4 +81,25 @@ class MdnsUtilsTest {
         assertEquals(truncateServiceName("测试abcde", 7), "测试a")
         assertEquals(truncateServiceName("测试abcde", 100), "测试abcde")
     }
+
+    @Test
+    fun testEqualsLabelIgnoreDnsCase() {
+        assertTrue(equalsDnsLabelIgnoreDnsCase(arrayOf("TEST", "Test"), arrayOf("test", "test")))
+        assertFalse(equalsDnsLabelIgnoreDnsCase(arrayOf("TEST", "Test"), arrayOf("test")))
+        assertFalse(equalsDnsLabelIgnoreDnsCase(arrayOf("Test"), arrayOf("test", "test")))
+        assertFalse(equalsDnsLabelIgnoreDnsCase(arrayOf("TEST", "Test"), arrayOf("test", "tést")))
+    }
+
+    @Test
+    fun testTypeEqualsOrIsSubtype() {
+        assertTrue(MdnsUtils.typeEqualsOrIsSubtype(arrayOf("_type", "_tcp", "local"),
+            arrayOf("_type", "_TCP", "local")))
+        assertTrue(MdnsUtils.typeEqualsOrIsSubtype(arrayOf("_type", "_tcp", "local"),
+            arrayOf("a", "_SUB", "_type", "_TCP", "local")))
+        assertFalse(MdnsUtils.typeEqualsOrIsSubtype(arrayOf("_sub", "_type", "_tcp", "local"),
+                arrayOf("_type", "_TCP", "local")))
+        assertFalse(MdnsUtils.typeEqualsOrIsSubtype(
+                arrayOf("a", "_other", "_type", "_tcp", "local"),
+                arrayOf("a", "_SUB", "_type", "_TCP", "local")))
+    }
 }