[mdns] add support for advertising subtypes

This commit adds support of advertising and discovering services
with subtypes.

With this change, client can publish a new service with subtypes with
code:
```
NsdServiceInfo info = new NsdServiceInfo();
info.setServiceName("My Service");
info.setServiceType("_meshcop._udp");
info.setSubtypes(Set.of("_abc"));

nsdManager.registerService(info, PROTOCOL_DNS_SD, listener);
```

Bug: 265095929
Test: atest CtsNetTestCases FrameworksNetTests
Change-Id: Ia83182e2d43002243d1ef4357d14a8056d7da14b

framework-t/api/current.txt

@@ -251,6 +251,7 @@ package android.net.nsd {
     method public int getPort();
     method public String getServiceName();
     method public String getServiceType();
+    method @FlaggedApi("com.android.net.flags.nsd_subtypes_support_enabled") @NonNull public java.util.Set<java.lang.String> getSubtypes();
     method public void removeAttribute(String);
     method public void setAttribute(String, String);
     method @Deprecated public void setHost(java.net.InetAddress);
@@ -259,6 +260,7 @@ package android.net.nsd {
     method public void setPort(int);
     method public void setServiceName(String);
     method public void setServiceType(String);
+    method @FlaggedApi("com.android.net.flags.nsd_subtypes_support_enabled") public void setSubtypes(@NonNull java.util.Set<java.lang.String>);
     method public void writeToParcel(android.os.Parcel, int);
     field @NonNull public static final android.os.Parcelable.Creator<android.net.nsd.NsdServiceInfo> CREATOR;
   }

framework-t/src/android/net/nsd/NsdManager.java

@@ -150,6 +150,8 @@ public final class NsdManager {
     public static class Flags {
         static final String REGISTER_NSD_OFFLOAD_ENGINE_API =
                 "com.android.net.flags.register_nsd_offload_engine_api";
+        static final String NSD_SUBTYPES_SUPPORT_ENABLED =
+                "com.android.net.flags.nsd_subtypes_support_enabled";
     }
 
     /**

framework-t/src/android/net/nsd/NsdServiceInfo.java

@@ -16,6 +16,9 @@
 
 package android.net.nsd;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import android.annotation.FlaggedApi;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.compat.annotation.UnsupportedAppUsage;
@@ -24,6 +27,7 @@ import android.os.Parcel;
 import android.os.Parcelable;
 import android.text.TextUtils;
 import android.util.ArrayMap;
+import android.util.ArraySet;
 import android.util.Log;
 
 import com.android.net.module.util.InetAddressUtils;
@@ -35,6 +39,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 /**
  * A class representing service information for network service discovery
@@ -48,6 +53,8 @@ public final class NsdServiceInfo implements Parcelable {
 
     private String mServiceType;
 
+    private final Set<String> mSubtypes = new ArraySet<>();
+
     private final ArrayMap<String, byte[]> mTxtRecord = new ArrayMap<>();
 
     private final List<InetAddress> mHostAddresses = new ArrayList<>();
@@ -391,11 +398,41 @@ public final class NsdServiceInfo implements Parcelable {
         mInterfaceIndex = interfaceIndex;
     }
 
+    /**
+     * Sets the subtypes to be advertised for this service instance.
+     *
+     * The elements in {@code subtypes} should be the subtype identifiers which have the trailing
+     * "._sub" removed. For example, the subtype should be "_printer" for
+     * "_printer._sub._http._tcp.local".
+     *
+     * Only one subtype will be registered if multiple elements of {@code subtypes} have the same
+     * case-insensitive value.
+     */
+    @FlaggedApi(NsdManager.Flags.NSD_SUBTYPES_SUPPORT_ENABLED)
+    public void setSubtypes(@NonNull Set<String> subtypes) {
+        mSubtypes.clear();
+        mSubtypes.addAll(subtypes);
+    }
+
+    /**
+     * Returns subtypes of this service instance.
+     *
+     * When this object is returned by the service discovery/browse APIs (etc. {@link
+     * NsdManager.DiscoveryListener}), the return value may or may not include the subtypes of this
+     * service.
+     */
+    @FlaggedApi(NsdManager.Flags.NSD_SUBTYPES_SUPPORT_ENABLED)
+    @NonNull
+    public Set<String> getSubtypes() {
+        return Collections.unmodifiableSet(mSubtypes);
+    }
+
     @Override
     public String toString() {
         StringBuilder sb = new StringBuilder();
         sb.append("name: ").append(mServiceName)
                 .append(", type: ").append(mServiceType)
+                .append(", subtypes: ").append(TextUtils.join(", ", mSubtypes))
                 .append(", hostAddresses: ").append(TextUtils.join(", ", mHostAddresses))
                 .append(", port: ").append(mPort)
                 .append(", network: ").append(mNetwork);
@@ -414,6 +451,7 @@ public final class NsdServiceInfo implements Parcelable {
     public void writeToParcel(Parcel dest, int flags) {
         dest.writeString(mServiceName);
         dest.writeString(mServiceType);
+        dest.writeStringList(new ArrayList<>(mSubtypes));
         dest.writeInt(mPort);
 
         // TXT record key/value pairs.
@@ -445,6 +483,7 @@ public final class NsdServiceInfo implements Parcelable {
                 NsdServiceInfo info = new NsdServiceInfo();
                 info.mServiceName = in.readString();
                 info.mServiceType = in.readString();
+                info.setSubtypes(new ArraySet<>(in.createStringArrayList()));
                 info.mPort = in.readInt();
 
                 // TXT record key/value pairs.

tests/common/java/android/net/nsd/NsdServiceInfoTest.java

@@ -18,6 +18,7 @@ package android.net.nsd;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
@@ -40,6 +41,7 @@ import java.net.InetAddress;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 @RunWith(DevSdkIgnoreRunner.class)
 @SmallTest
@@ -114,6 +116,7 @@ public class NsdServiceInfoTest {
         NsdServiceInfo fullInfo = new NsdServiceInfo();
         fullInfo.setServiceName("kitten");
         fullInfo.setServiceType("_kitten._tcp");
+        fullInfo.setSubtypes(Set.of("_thread", "_matter"));
         fullInfo.setPort(4242);
         fullInfo.setHostAddresses(List.of(IPV4_ADDRESS));
         fullInfo.setNetwork(new Network(123));
@@ -149,7 +152,7 @@ public class NsdServiceInfoTest {
         assertFalse(attributedInfo.getAttributes().keySet().contains("sticky"));
     }
 
-    public void checkParcelable(NsdServiceInfo original) {
+    private static void checkParcelable(NsdServiceInfo original) {
         // Write to parcel.
         Parcel p = Parcel.obtain();
         Bundle writer = new Bundle();
@@ -179,11 +182,20 @@ public class NsdServiceInfoTest {
         }
     }
 
-    public void assertEmptyServiceInfo(NsdServiceInfo shouldBeEmpty) {
+    private static void assertEmptyServiceInfo(NsdServiceInfo shouldBeEmpty) {
         byte[] txtRecord = shouldBeEmpty.getTxtRecord();
         if (txtRecord == null || txtRecord.length == 0) {
             return;
         }
         fail("NsdServiceInfo.getTxtRecord did not return null but " + Arrays.toString(txtRecord));
     }
+
+    @Test
+    public void testSubtypesValidSubtypesSuccess() {
+        NsdServiceInfo info = new NsdServiceInfo();
+
+        info.setSubtypes(Set.of("_thread", "_matter"));
+
+        assertEquals(Set.of("_thread", "_matter"), info.getSubtypes());
+    }
 }

tests/cts/net/src/android/net/cts/NsdManagerTest.kt

@@ -43,6 +43,7 @@ import android.net.cts.NsdDiscoveryRecord.DiscoveryEvent.DiscoveryStarted
 import android.net.cts.NsdDiscoveryRecord.DiscoveryEvent.DiscoveryStopped
 import android.net.cts.NsdDiscoveryRecord.DiscoveryEvent.ServiceFound
 import android.net.cts.NsdDiscoveryRecord.DiscoveryEvent.ServiceLost
+import android.net.cts.NsdRegistrationRecord.RegistrationEvent.RegistrationFailed
 import android.net.cts.NsdRegistrationRecord.RegistrationEvent.ServiceRegistered
 import android.net.cts.NsdRegistrationRecord.RegistrationEvent.ServiceUnregistered
 import android.net.cts.NsdResolveRecord.ResolveEvent.ResolutionStopped
@@ -991,6 +992,104 @@ class NsdManagerTest {
         }
     }
 
+    @Test
+    fun testSubtypeAdvertisingAndDiscovery_withSetSubtypesApi() {
+        runSubtypeAdvertisingAndDiscoveryTest(useLegacySpecifier = false)
+    }
+
+    @Test
+    fun testSubtypeAdvertisingAndDiscovery_withSetSubtypesApiAndLegacySpecifier() {
+        runSubtypeAdvertisingAndDiscoveryTest(useLegacySpecifier = true)
+    }
+
+    private fun runSubtypeAdvertisingAndDiscoveryTest(useLegacySpecifier: Boolean) {
+        val si = makeTestServiceInfo(network = testNetwork1.network)
+        if (useLegacySpecifier) {
+            si.subtypes = setOf("_subtype1")
+
+            // Test "_type._tcp.local,_subtype" syntax with the registration
+            si.serviceType = si.serviceType + ",_subtype2"
+        } else {
+            si.subtypes = setOf("_subtype1", "_subtype2")
+        }
+
+        val registrationRecord = NsdRegistrationRecord()
+
+        val baseTypeDiscoveryRecord = NsdDiscoveryRecord()
+        val subtype1DiscoveryRecord = NsdDiscoveryRecord()
+        val subtype2DiscoveryRecord = NsdDiscoveryRecord()
+        val otherSubtypeDiscoveryRecord = NsdDiscoveryRecord()
+        tryTest {
+            registerService(registrationRecord, si)
+
+            nsdManager.discoverServices(serviceType, NsdManager.PROTOCOL_DNS_SD,
+                    testNetwork1.network, Executor { it.run() }, baseTypeDiscoveryRecord)
+
+            // Test "<subtype>._type._tcp.local" syntax with discovery. Note this is not
+            // "<subtype>._sub._type._tcp.local".
+            nsdManager.discoverServices("_othersubtype.$serviceType",
+                    NsdManager.PROTOCOL_DNS_SD,
+                    testNetwork1.network, Executor { it.run() }, otherSubtypeDiscoveryRecord)
+            nsdManager.discoverServices("_subtype1.$serviceType",
+                    NsdManager.PROTOCOL_DNS_SD,
+                    testNetwork1.network, Executor { it.run() }, subtype1DiscoveryRecord)
+            nsdManager.discoverServices("_subtype2.$serviceType",
+                    NsdManager.PROTOCOL_DNS_SD,
+                    testNetwork1.network, Executor { it.run() }, subtype2DiscoveryRecord)
+
+            val info1 = subtype1DiscoveryRecord.waitForServiceDiscovered(
+                    serviceName, serviceType, testNetwork1.network)
+            assertTrue(info1.subtypes.contains("_subtype1"))
+            val info2 = subtype2DiscoveryRecord.waitForServiceDiscovered(
+                    serviceName, serviceType, testNetwork1.network)
+            assertTrue(info2.subtypes.contains("_subtype2"))
+            baseTypeDiscoveryRecord.waitForServiceDiscovered(
+                    serviceName, serviceType, testNetwork1.network)
+            otherSubtypeDiscoveryRecord.expectCallback<DiscoveryStarted>()
+            // The subtype callback was registered later but called, no need for an extra delay
+            otherSubtypeDiscoveryRecord.assertNoCallback(timeoutMs = 0)
+        } cleanupStep {
+            nsdManager.stopServiceDiscovery(baseTypeDiscoveryRecord)
+            nsdManager.stopServiceDiscovery(subtype1DiscoveryRecord)
+            nsdManager.stopServiceDiscovery(subtype2DiscoveryRecord)
+            nsdManager.stopServiceDiscovery(otherSubtypeDiscoveryRecord)
+
+            baseTypeDiscoveryRecord.expectCallback<DiscoveryStopped>()
+            subtype1DiscoveryRecord.expectCallback<DiscoveryStopped>()
+            subtype2DiscoveryRecord.expectCallback<DiscoveryStopped>()
+            otherSubtypeDiscoveryRecord.expectCallback<DiscoveryStopped>()
+        } cleanup {
+            nsdManager.unregisterService(registrationRecord)
+        }
+    }
+
+    @Test
+    fun testSubtypeAdvertising_tooManySubtypes_returnsFailureBadParameters() {
+        val si = makeTestServiceInfo(network = testNetwork1.network)
+        // Sets 101 subtypes in total
+        val seq = generateSequence(1) { it + 1}
+        si.subtypes = seq.take(100).toList().map {it -> "_subtype" + it}.toSet()
+        si.serviceType = si.serviceType + ",_subtype"
+
+        val record = NsdRegistrationRecord()
+        nsdManager.registerService(si, NsdManager.PROTOCOL_DNS_SD, Executor { it.run() }, record)
+
+        val failedCb = record.expectCallback<RegistrationFailed>(REGISTRATION_TIMEOUT_MS)
+        assertEquals(NsdManager.FAILURE_BAD_PARAMETERS, failedCb.errorCode)
+    }
+
+    @Test
+    fun testSubtypeAdvertising_emptySubtypeLabel_returnsFailureBadParameters() {
+        val si = makeTestServiceInfo(network = testNetwork1.network)
+        si.subtypes = setOf("")
+
+        val record = NsdRegistrationRecord()
+        nsdManager.registerService(si, NsdManager.PROTOCOL_DNS_SD, Executor { it.run() }, record)
+
+        val failedCb = record.expectCallback<RegistrationFailed>(REGISTRATION_TIMEOUT_MS)
+        assertEquals(NsdManager.FAILURE_BAD_PARAMETERS, failedCb.errorCode)
+    }
+
     @Test
     fun testRegisterWithConflictDuringProbing() {
         // This test requires shims supporting T+ APIs (NsdServiceInfo.network)