[mdns] add API for setting/getting TTL value

To support Thread Border Router use case, an Android device needs to act
as a mDNS service discovery (RFC 8766) & advertising proxy (
https://datatracker.ietf.org/doc/draft-ietf-dnssd-advertising-proxy).
This means it needs to advertise and discover DNS-SD services of custom
TTL value on behalf of other devices.

This commit fulfills this requirement by adding TTL getter/setter to
NsdServiceInfo. When registering a service, the specified TTL will be
used for corresponding resource records.

Bug: 284903641
Test: atest CtsNetTestCases FrameworksNetTests
Change-Id: I23837834847dc3a0fb452c5929a1b36e3fc1fb3f
diff --git a/framework-t/src/android/net/nsd/AdvertisingRequest.java b/framework-t/src/android/net/nsd/AdvertisingRequest.java
index b1ef98f..d778654 100644
--- a/framework-t/src/android/net/nsd/AdvertisingRequest.java
+++ b/framework-t/src/android/net/nsd/AdvertisingRequest.java
@@ -15,13 +15,17 @@
  */
 package android.net.nsd;
 
+import static java.util.Objects.requireNonNull;
+
 import android.annotation.LongDef;
 import android.annotation.NonNull;
+import android.annotation.Nullable;
 import android.os.Parcel;
 import android.os.Parcelable;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
+import java.time.Duration;
 import java.util.Objects;
 
 /**
@@ -34,7 +38,7 @@
     /**
      * Only update the registration without sending exit and re-announcement.
      */
-    public static final int NSD_ADVERTISING_UPDATE_ONLY = 1;
+    public static final long NSD_ADVERTISING_UPDATE_ONLY = 1;
 
 
     @NonNull
@@ -46,7 +50,9 @@
                             NsdServiceInfo.class.getClassLoader(), NsdServiceInfo.class);
                     final int protocolType = in.readInt();
                     final long advertiseConfig = in.readLong();
-                    return new AdvertisingRequest(serviceInfo, protocolType, advertiseConfig);
+                    final long ttlSeconds = in.readLong();
+                    final Duration ttl = ttlSeconds < 0 ? null : Duration.ofSeconds(ttlSeconds);
+                    return new AdvertisingRequest(serviceInfo, protocolType, advertiseConfig, ttl);
                 }
 
                 @Override
@@ -60,6 +66,9 @@
     // Bitmask of @AdvertisingConfig flags. Uses a long to allow 64 possible flags in the future.
     private final long mAdvertisingConfig;
 
+    @Nullable
+    private final Duration mTtl;
+
     /**
      * @hide
      */
@@ -73,10 +82,11 @@
      * The constructor for the advertiseRequest
      */
     private AdvertisingRequest(@NonNull NsdServiceInfo serviceInfo, int protocolType,
-            long advertisingConfig) {
+            long advertisingConfig, @NonNull Duration ttl) {
         mServiceInfo = serviceInfo;
         mProtocolType = protocolType;
         mAdvertisingConfig = advertisingConfig;
+        mTtl = ttl;
     }
 
     /**
@@ -101,12 +111,25 @@
         return mAdvertisingConfig;
     }
 
+    /**
+     * Returns the time interval that the resource records may be cached on a DNS resolver or
+     * {@code null} if not specified.
+     *
+     * @hide
+     */
+    // @FlaggedApi(NsdManager.Flags.NSD_CUSTOM_TTL_ENABLED)
+    @Nullable
+    public Duration getTtl() {
+        return mTtl;
+    }
+
     @Override
     public String toString() {
         StringBuilder sb = new StringBuilder();
         sb.append("serviceInfo: ").append(mServiceInfo)
                 .append(", protocolType: ").append(mProtocolType)
-                .append(", advertisingConfig: ").append(mAdvertisingConfig);
+                .append(", advertisingConfig: ").append(mAdvertisingConfig)
+                .append(", ttl: ").append(mTtl);
         return sb.toString();
     }
 
@@ -120,13 +143,14 @@
             final AdvertisingRequest otherRequest = (AdvertisingRequest) other;
             return mServiceInfo.equals(otherRequest.mServiceInfo)
                     && mProtocolType == otherRequest.mProtocolType
-                    && mAdvertisingConfig == otherRequest.mAdvertisingConfig;
+                    && mAdvertisingConfig == otherRequest.mAdvertisingConfig
+                    && Objects.equals(mTtl, otherRequest.mTtl);
         }
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(mServiceInfo, mProtocolType, mAdvertisingConfig);
+        return Objects.hash(mServiceInfo, mProtocolType, mAdvertisingConfig, mTtl);
     }
 
     @Override
@@ -139,6 +163,7 @@
         dest.writeParcelable(mServiceInfo, flags);
         dest.writeInt(mProtocolType);
         dest.writeLong(mAdvertisingConfig);
+        dest.writeLong(mTtl == null ? -1 : mTtl.getSeconds());
     }
 
 //    @FlaggedApi(NsdManager.Flags.ADVERTISE_REQUEST_API)
@@ -151,6 +176,8 @@
         private final NsdServiceInfo mServiceInfo;
         private final int mProtocolType;
         private long mAdvertisingConfig;
+        @Nullable
+        private Duration mTtl;
         /**
          * Creates a new {@link Builder} object.
          */
@@ -170,11 +197,44 @@
             return this;
         }
 
+        /**
+         * Sets the time interval that the resource records may be cached on a DNS resolver.
+         *
+         * If this method is not called or {@code ttl} is {@code null}, default TTL values
+         * will be used for the service when it's registered. Otherwise, the {@code ttl}
+         * will be used for all resource records of this service.
+         *
+         * When registering a service, {@link NsdManager#FAILURE_BAD_PARAMETERS} will be returned
+         * if {@code ttl} is smaller than 30 seconds.
+         *
+         * Note: only number of seconds of {@code ttl} is used.
+         *
+         * @param ttl the maximum duration that the DNS resource records will be cached
+         *
+         * @see AdvertisingRequest#getTtl
+         * @hide
+         */
+        // @FlaggedApi(NsdManager.Flags.NSD_CUSTOM_TTL_ENABLED)
+        @NonNull
+        public Builder setTtl(@Nullable Duration ttl) {
+            if (ttl == null) {
+                mTtl = null;
+                return this;
+            }
+            final long ttlSeconds = ttl.getSeconds();
+            if (ttlSeconds < 0 || ttlSeconds > 0xffffffffL) {
+                throw new IllegalArgumentException(
+                        "ttlSeconds exceeds the allowed range (value = " + ttlSeconds
+                                + ", allowedRanged = [0, 0xffffffffL])");
+            }
+            mTtl = Duration.ofSeconds(ttlSeconds);
+            return this;
+        }
 
         /** Creates a new {@link AdvertisingRequest} object. */
         @NonNull
         public AdvertisingRequest build() {
-            return new AdvertisingRequest(mServiceInfo, mProtocolType, mAdvertisingConfig);
+            return new AdvertisingRequest(mServiceInfo, mProtocolType, mAdvertisingConfig, mTtl);
         }
     }
 }
diff --git a/framework-t/src/android/net/nsd/NsdManager.java b/framework-t/src/android/net/nsd/NsdManager.java
index f6e1324..1001423 100644
--- a/framework-t/src/android/net/nsd/NsdManager.java
+++ b/framework-t/src/android/net/nsd/NsdManager.java
@@ -160,6 +160,8 @@
                 "com.android.net.flags.advertise_request_api";
         static final String NSD_CUSTOM_HOSTNAME_ENABLED =
                 "com.android.net.flags.nsd_custom_hostname_enabled";
+        static final String NSD_CUSTOM_TTL_ENABLED =
+                "com.android.net.flags.nsd_custom_ttl_enabled";
     }
 
     /**
@@ -327,6 +329,20 @@
     /** Dns based service discovery protocol */
     public static final int PROTOCOL_DNS_SD = 0x0001;
 
+    /**
+     * The minimum TTL seconds which is allowed for a service registration.
+     *
+     * @hide
+     */
+    public static final long TTL_SECONDS_MIN = 30L;
+
+    /**
+     * The maximum TTL seconds which is allowed for a service registration.
+     *
+     * @hide
+     */
+    public static final long TTL_SECONDS_MAX = 10 * 3600L;
+
     private static final SparseArray<String> EVENT_NAMES = new SparseArray<>();
     static {
         EVENT_NAMES.put(DISCOVER_SERVICES, "DISCOVER_SERVICES");
diff --git a/framework-t/src/android/net/nsd/NsdServiceInfo.java b/framework-t/src/android/net/nsd/NsdServiceInfo.java
index 146d4ca..4b1252e 100644
--- a/framework-t/src/android/net/nsd/NsdServiceInfo.java
+++ b/framework-t/src/android/net/nsd/NsdServiceInfo.java
@@ -19,12 +19,15 @@
 import static java.nio.charset.StandardCharsets.UTF_8;
 
 import android.annotation.FlaggedApi;
+import android.annotation.IntRange;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.compat.annotation.UnsupportedAppUsage;
 import android.net.Network;
+import android.net.nsd.NsdManager.RegistrationListener;
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.os.Process;
 import android.text.TextUtils;
 import android.util.ArrayMap;
 import android.util.ArraySet;
@@ -35,6 +38,7 @@
 import java.io.UnsupportedEncodingException;
 import java.net.InetAddress;
 import java.nio.charset.StandardCharsets;
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -71,6 +75,10 @@
 
     private int mInterfaceIndex;
 
+    // The timestamp that all resource records associated with this service are considered invalid.
+    @Nullable
+    private Instant mExpirationTime;
+
     public NsdServiceInfo() {
         mSubtypes = new ArraySet<>();
         mTxtRecord = new ArrayMap<>();
@@ -99,6 +107,7 @@
         mPort = other.getPort();
         mNetwork = other.getNetwork();
         mInterfaceIndex = other.getInterfaceIndex();
+        mExpirationTime = other.getExpirationTime();
     }
 
     /** Get the service name */
@@ -490,6 +499,38 @@
         return Collections.unmodifiableSet(mSubtypes);
     }
 
+    /**
+     * Sets the timestamp after when this service is expired.
+     *
+     * Note: only number of seconds of {@code expirationTime} is used.
+     *
+     * @hide
+     */
+    public void setExpirationTime(@Nullable Instant expirationTime) {
+        if (expirationTime == null) {
+            mExpirationTime = null;
+        } else {
+            mExpirationTime = Instant.ofEpochSecond(expirationTime.getEpochSecond());
+        }
+    }
+
+    /**
+     * Returns the timestamp after when this service is expired or {@code null} if it's unknown.
+     *
+     * A service is considered expired if any of its DNS record is expired.
+     *
+     * Clients that are depending on the refreshness of the service information should not continue
+     * use this service after the returned timestamp. Instead, clients may re-send queries for the
+     * service to get updated the service information.
+     *
+     * @hide
+     */
+    // @FlaggedApi(NsdManager.Flags.NSD_CUSTOM_TTL_ENABLED)
+    @Nullable
+    public Instant getExpirationTime() {
+        return mExpirationTime;
+    }
+
     @Override
     public String toString() {
         StringBuilder sb = new StringBuilder();
@@ -499,7 +540,8 @@
                 .append(", hostAddresses: ").append(TextUtils.join(", ", mHostAddresses))
                 .append(", hostname: ").append(mHostname)
                 .append(", port: ").append(mPort)
-                .append(", network: ").append(mNetwork);
+                .append(", network: ").append(mNetwork)
+                .append(", expirationTime: ").append(mExpirationTime);
 
         byte[] txtRecord = getTxtRecord();
         sb.append(", txtRecord: ").append(new String(txtRecord, StandardCharsets.UTF_8));
@@ -539,6 +581,7 @@
             InetAddressUtils.parcelInetAddress(dest, address, flags);
         }
         dest.writeString(mHostname);
+        dest.writeLong(mExpirationTime != null ? mExpirationTime.getEpochSecond() : -1);
     }
 
     /** Implement the Parcelable interface */
@@ -569,6 +612,8 @@
                     info.mHostAddresses.add(InetAddressUtils.unparcelInetAddress(in));
                 }
                 info.mHostname = in.readString();
+                final long seconds = in.readLong();
+                info.setExpirationTime(seconds < 0 ? null : Instant.ofEpochSecond(seconds));
                 return info;
             }
 
diff --git a/tests/unit/java/android/net/nsd/AdvertisingRequestTest.kt b/tests/unit/java/android/net/nsd/AdvertisingRequestTest.kt
new file mode 100644
index 0000000..fa8b0d5
--- /dev/null
+++ b/tests/unit/java/android/net/nsd/AdvertisingRequestTest.kt
@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2024 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.nsd
+
+import android.net.Network
+import android.net.nsd.AdvertisingRequest
+import android.net.nsd.AdvertisingRequest.NSD_ADVERTISING_UPDATE_ONLY
+import android.net.nsd.NsdManager
+import android.net.nsd.NsdManager.PROTOCOL_DNS_SD
+import android.net.nsd.NsdServiceInfo
+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.parcelingRoundTrip
+import com.android.testutils.assertThrows
+import java.time.Duration
+import kotlin.test.assertEquals
+import kotlin.test.assertNotEquals
+import kotlin.test.assertNull
+import org.junit.Test
+import org.junit.runner.RunWith
+
+// TODO: move this class to CTS tests when AdvertisingRequest is made public
+/** Unit tests for {@link AdvertisingRequest}. */
+@IgnoreUpTo(Build.VERSION_CODES.S_V2)
+@RunWith(DevSdkIgnoreRunner::class)
+@SmallTest
+@ConnectivityModuleTest
+class AdvertisingRequestTest {
+    @Test
+    fun testParcelingIsLossLess() {
+        val info = NsdServiceInfo().apply {
+            serviceType = "_ipp._tcp"
+        }
+        val beforeParcel = AdvertisingRequest.Builder(info, PROTOCOL_DNS_SD)
+                .setAdvertisingConfig(NSD_ADVERTISING_UPDATE_ONLY)
+                .setTtl(Duration.ofSeconds(30L))
+                .build()
+
+        val afterParcel = parcelingRoundTrip(beforeParcel)
+
+        assertEquals(beforeParcel.serviceInfo.serviceType, afterParcel.serviceInfo.serviceType);
+        assertEquals(beforeParcel.advertisingConfig, afterParcel.advertisingConfig);
+    }
+
+@Test
+fun testBuilder_setNullTtl_success() {
+    val info = NsdServiceInfo().apply {
+        serviceType = "_ipp._tcp"
+    }
+    val request = AdvertisingRequest.Builder(info, PROTOCOL_DNS_SD)
+            .setTtl(null)
+            .build()
+
+    assertNull(request.ttl)
+}
+
+    @Test
+    fun testBuilder_setPropertiesSuccess() {
+        val info = NsdServiceInfo().apply {
+            serviceType = "_ipp._tcp"
+        }
+        val request = AdvertisingRequest.Builder(info, PROTOCOL_DNS_SD)
+                .setAdvertisingConfig(NSD_ADVERTISING_UPDATE_ONLY)
+                .setTtl(Duration.ofSeconds(100L))
+                .build()
+
+        assertEquals("_ipp._tcp", request.serviceInfo.serviceType)
+        assertEquals(PROTOCOL_DNS_SD, request.protocolType)
+        assertEquals(NSD_ADVERTISING_UPDATE_ONLY, request.advertisingConfig)
+        assertEquals(Duration.ofSeconds(100L), request.ttl)
+    }
+
+    @Test
+    fun testEquality() {
+        val info = NsdServiceInfo().apply {
+            serviceType = "_ipp._tcp"
+        }
+        val request1 = AdvertisingRequest.Builder(info, PROTOCOL_DNS_SD).build()
+        val request2 = AdvertisingRequest.Builder(info, PROTOCOL_DNS_SD).build()
+        val request3 = AdvertisingRequest.Builder(info, PROTOCOL_DNS_SD)
+                .setAdvertisingConfig(NSD_ADVERTISING_UPDATE_ONLY)
+                .setTtl(Duration.ofSeconds(120L))
+                .build()
+        val request4 = AdvertisingRequest.Builder(info, PROTOCOL_DNS_SD)
+                .setAdvertisingConfig(NSD_ADVERTISING_UPDATE_ONLY)
+                .setTtl(Duration.ofSeconds(120L))
+                .build()
+
+        assertEquals(request1, request2)
+        assertEquals(request3, request4)
+        assertNotEquals(request1, request3)
+        assertNotEquals(request2, request4)
+    }
+}
diff --git a/tests/unit/java/android/net/nsd/NsdManagerTest.java b/tests/unit/java/android/net/nsd/NsdManagerTest.java
index 951675c..76a649e 100644
--- a/tests/unit/java/android/net/nsd/NsdManagerTest.java
+++ b/tests/unit/java/android/net/nsd/NsdManagerTest.java
@@ -23,6 +23,7 @@
 import static org.junit.Assert.fail;
 import static org.mockito.ArgumentMatchers.anyBoolean;
 import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.anyInt;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
@@ -54,6 +55,7 @@
 
 import java.net.InetAddress;
 import java.util.List;
+import java.time.Duration;
 
 @DevSdkIgnoreRunner.MonitorThreadLeak
 @RunWith(DevSdkIgnoreRunner.class)
@@ -224,6 +226,23 @@
         verify(listener, timeout(mTimeoutMs).times(1)).onServiceRegistered(request);
     }
 
+    @Test
+    public void testRegisterServiceWithCustomTtl() throws Exception {
+        final NsdManager manager = mManager;
+        final NsdServiceInfo info = new NsdServiceInfo("another_name2", "another_type2");
+        info.setPort(2203);
+        final AdvertisingRequest request = new AdvertisingRequest.Builder(info, PROTOCOL)
+                .setTtl(Duration.ofSeconds(30)).build();
+        final NsdManager.RegistrationListener listener = mock(
+                NsdManager.RegistrationListener.class);
+
+        manager.registerService(request, Runnable::run, listener);
+
+        AdvertisingRequest capturedRequest = getAdvertisingRequest(
+                req -> verify(mServiceConn).registerService(anyInt(), req.capture()));
+        assertEquals(request, capturedRequest);
+    }
+
     private void doTestRegisterService() throws Exception {
         NsdManager manager = mManager;
 
@@ -501,4 +520,12 @@
         verifier.accept(captor);
         return captor.getValue();
     }
+
+    AdvertisingRequest getAdvertisingRequest(
+            ThrowingConsumer<ArgumentCaptor<AdvertisingRequest>> verifier) throws Exception {
+        final ArgumentCaptor<AdvertisingRequest> captor =
+                ArgumentCaptor.forClass(AdvertisingRequest.class);
+        verifier.accept(captor);
+        return captor.getValue();
+    }
 }