[mdns] add API for discovery with subtype

This commit adds support of discovering services with explicit subtype.

With this change, a service can be discovered with subtype with:
```
nsdManager.discoverServices(
        new DiscoveryRequest.Builder("_http._tcp", PROTOCOL_DNS_SD)
	        .setSubtype("_printer").build(),
	executor, listener);
```

Bug: 265095929
Test: atest CtsNetTestCases FrameworksNetTests
Change-Id: Iba76283a003cf2d52a8c26e1de872c3e8e433350
diff --git a/tests/cts/net/Android.bp b/tests/cts/net/Android.bp
index 3d53d6c..f0e0ae8 100644
--- a/tests/cts/net/Android.bp
+++ b/tests/cts/net/Android.bp
@@ -54,6 +54,7 @@
         "junit",
         "junit-params",
         "modules-utils-build",
+        "net-tests-utils",
         "net-utils-framework-common",
         "truth",
         "TetheringIntegrationTestsBaseLib",
diff --git a/tests/cts/net/src/android/net/cts/DiscoveryRequestTest.kt b/tests/cts/net/src/android/net/cts/DiscoveryRequestTest.kt
new file mode 100644
index 0000000..909a5bc
--- /dev/null
+++ b/tests/cts/net/src/android/net/cts/DiscoveryRequestTest.kt
@@ -0,0 +1,90 @@
+/*
+ * 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 android.net.cts
+
+import android.net.Network
+import android.net.nsd.DiscoveryRequest
+import android.os.Build
+import androidx.test.filters.SmallTest
+import com.android.testutils.ConnectivityModuleTest
+import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo
+import com.android.testutils.DevSdkIgnoreRunner
+import com.android.testutils.assertParcelingIsLossless
+import com.android.testutils.assertThrows
+import kotlin.test.assertEquals
+import kotlin.test.assertNotEquals
+import org.junit.Test
+import org.junit.runner.RunWith
+
+/** CTS tests for {@link DiscoveryRequest}. */
+@IgnoreUpTo(Build.VERSION_CODES.S_V2)
+@RunWith(DevSdkIgnoreRunner::class)
+@SmallTest
+@ConnectivityModuleTest
+class DiscoveryRequestTest {
+    @Test
+    fun testParcelingIsLossLess() {
+        val requestWithNullFields =
+                DiscoveryRequest.Builder("_ipps._tcp").build()
+        val requestWithAllFields =
+                DiscoveryRequest.Builder("_ipps._tcp")
+                                .setSubtype("_xyz")
+                                .setNetwork(Network(1))
+                                .build()
+
+        assertParcelingIsLossless(requestWithNullFields)
+        assertParcelingIsLossless(requestWithAllFields)
+    }
+
+    @Test
+    fun testBuilder_success() {
+        val request = DiscoveryRequest.Builder("_ipps._tcp")
+                                      .setSubtype("_xyz")
+                                      .setNetwork(Network(1))
+                                      .build()
+
+        assertEquals("_ipps._tcp", request.serviceType)
+        assertEquals("_xyz", request.subtype)
+        assertEquals(Network(1), request.network)
+    }
+
+    @Test
+    fun testBuilderConstructor_emptyServiceType_throwsIllegalArgument() {
+        assertThrows(IllegalArgumentException::class.java) {
+            DiscoveryRequest.Builder("")
+        }
+    }
+
+    @Test
+    fun testEquality() {
+        val request1 = DiscoveryRequest.Builder("_ipps._tcp").build()
+        val request2 = DiscoveryRequest.Builder("_ipps._tcp").build()
+        val request3 = DiscoveryRequest.Builder("_ipps._tcp")
+                .setSubtype("_xyz")
+                .setNetwork(Network(1))
+                .build()
+        val request4 = DiscoveryRequest.Builder("_ipps._tcp")
+                .setSubtype("_xyz")
+                .setNetwork(Network(1))
+                .build()
+
+        assertEquals(request1, request2)
+        assertEquals(request3, request4)
+        assertNotEquals(request1, request3)
+        assertNotEquals(request2, request4)
+    }
+}
diff --git a/tests/cts/net/src/android/net/cts/NsdManagerTest.kt b/tests/cts/net/src/android/net/cts/NsdManagerTest.kt
index e433442..8f9f8c7 100644
--- a/tests/cts/net/src/android/net/cts/NsdManagerTest.kt
+++ b/tests/cts/net/src/android/net/cts/NsdManagerTest.kt
@@ -53,6 +53,7 @@
 import android.net.cts.NsdServiceInfoCallbackRecord.ServiceInfoCallbackEvent.ServiceUpdatedLost
 import android.net.cts.NsdServiceInfoCallbackRecord.ServiceInfoCallbackEvent.UnregisterCallbackSucceeded
 import android.net.cts.util.CtsNetUtils
+import android.net.nsd.DiscoveryRequest
 import android.net.nsd.NsdManager
 import android.net.nsd.NsdServiceInfo
 import android.net.nsd.OffloadEngine
@@ -113,6 +114,7 @@
 import kotlin.math.min
 import kotlin.test.assertEquals
 import kotlin.test.assertFailsWith
+import kotlin.test.assertNotEquals
 import kotlin.test.assertNotNull
 import kotlin.test.assertNull
 import kotlin.test.fail
@@ -1042,9 +1044,11 @@
             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)
+
+            nsdManager.discoverServices(
+                    DiscoveryRequest.Builder(serviceType).setSubtype("_subtype2")
+                            .setNetwork(testNetwork1.network).build(),
+                    Executor { it.run() }, subtype2DiscoveryRecord)
 
             val info1 = subtype1DiscoveryRecord.waitForServiceDiscovered(
                     serviceName, serviceType, testNetwork1.network)
@@ -1099,6 +1103,28 @@
     }
 
     @Test
+    fun testSubtypeDiscovery_typeMatchButSubtypeNotMatch_notDiscovered() {
+        val si1 = makeTestServiceInfo(network = testNetwork1.network).apply {
+            serviceType += ",_subtype1"
+        }
+        val registrationRecord = NsdRegistrationRecord()
+        val subtype2DiscoveryRecord = NsdDiscoveryRecord()
+        tryTest {
+            registerService(registrationRecord, si1)
+            val request = DiscoveryRequest.Builder(serviceType)
+                    .setSubtype("_subtype2").setNetwork(testNetwork1.network).build()
+            nsdManager.discoverServices(request, { it.run() }, subtype2DiscoveryRecord)
+            subtype2DiscoveryRecord.expectCallback<DiscoveryStarted>()
+            subtype2DiscoveryRecord.assertNoCallback(timeoutMs = 2000)
+        } cleanupStep {
+            nsdManager.stopServiceDiscovery(subtype2DiscoveryRecord)
+            subtype2DiscoveryRecord.expectCallback<DiscoveryStopped>()
+        } cleanup {
+            nsdManager.unregisterService(registrationRecord)
+        }
+    }
+
+    @Test
     fun testSubtypeAdvertising_tooManySubtypes_returnsFailureBadParameters() {
         val si = makeTestServiceInfo(network = testNetwork1.network)
         // Sets 101 subtypes in total
diff --git a/tests/unit/java/android/net/nsd/NsdManagerTest.java b/tests/unit/java/android/net/nsd/NsdManagerTest.java
index 461ead8..aabe8d3 100644
--- a/tests/unit/java/android/net/nsd/NsdManagerTest.java
+++ b/tests/unit/java/android/net/nsd/NsdManagerTest.java
@@ -285,6 +285,7 @@
     private void doTestDiscoverService() throws Exception {
         NsdManager manager = mManager;
 
+        DiscoveryRequest request1 = new DiscoveryRequest.Builder("a_type").build();
         NsdServiceInfo reply1 = new NsdServiceInfo("a_name", "a_type");
         NsdServiceInfo reply2 = new NsdServiceInfo("another_name", "a_type");
         NsdServiceInfo reply3 = new NsdServiceInfo("a_third_name", "a_type");
@@ -305,7 +306,7 @@
         int key2 = getRequestKey(req ->
                 verify(mServiceConn, times(2)).discoverServices(req.capture(), any()));
 
-        mCallback.onDiscoverServicesStarted(key2, reply1);
+        mCallback.onDiscoverServicesStarted(key2, request1);
         verify(listener, timeout(mTimeoutMs).times(1)).onDiscoveryStarted("a_type");
 
 
@@ -345,7 +346,7 @@
         int key3 = getRequestKey(req ->
                 verify(mServiceConn, times(3)).discoverServices(req.capture(), any()));
 
-        mCallback.onDiscoverServicesStarted(key3, reply1);
+        mCallback.onDiscoverServicesStarted(key3, request1);
         verify(listener, timeout(mTimeoutMs).times(1)).onDiscoveryStarted("a_type");
 
         // Client unregisters immediately, it fails