[mdns] add tests for verifying address of mDNS reply

Bug: 265095929
Test: atest FrameworksNetTests
Change-Id: I3499fb9dfc24fec9648f9c97d6028c3fca4f925a
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsRecordRepository.java b/service-t/src/com/android/server/connectivity/mdns/MdnsRecordRepository.java
index c8fe651..f9951a9 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsRecordRepository.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsRecordRepository.java
@@ -141,6 +141,9 @@
          * Last time (as per SystemClock.elapsedRealtime) when sent via unicast or multicast,
          * 0 if never
          */
+        // FIXME: the `lastSentTimeMs` and `lastAdvertisedTimeMs` should be maintained separately
+        // for IPv4 and IPv6, because neither IPv4 nor and IPv6 clients can receive replies in
+        // different address space.
         public long lastSentTimeMs;
 
         RecordInfo(NsdServiceInfo serviceInfo, T record, boolean sharedName) {
diff --git a/tests/unit/java/com/android/server/connectivity/mdns/MdnsRecordRepositoryTest.kt b/tests/unit/java/com/android/server/connectivity/mdns/MdnsRecordRepositoryTest.kt
index 69f039c..4b1f166 100644
--- a/tests/unit/java/com/android/server/connectivity/mdns/MdnsRecordRepositoryTest.kt
+++ b/tests/unit/java/com/android/server/connectivity/mdns/MdnsRecordRepositoryTest.kt
@@ -756,6 +756,34 @@
     }
 
     @Test
+    fun testGetReply_queryWithIpv4Address_replyWithIpv4Address() {
+        val repository = MdnsRecordRepository(thread.looper, deps, TEST_HOSTNAME, flags)
+        repository.initWithService(TEST_SERVICE_ID_1, TEST_SERVICE_1, setOf(TEST_SUBTYPE))
+        val query = makeQuery(TYPE_PTR to arrayOf("_testservice", "_tcp", "local"))
+
+        val srcIpv4 = InetSocketAddress(parseNumericAddress("192.0.2.123"), 5353)
+        val replyIpv4 = repository.getReply(query, srcIpv4)
+
+        assertNotNull(replyIpv4)
+        assertEquals(MdnsConstants.getMdnsIPv4Address(), replyIpv4.destination.address)
+        assertEquals(MdnsConstants.MDNS_PORT, replyIpv4.destination.port)
+    }
+
+    @Test
+    fun testGetReply_queryWithIpv6Address_replyWithIpv6Address() {
+        val repository = MdnsRecordRepository(thread.looper, deps, TEST_HOSTNAME, flags)
+        repository.initWithService(TEST_SERVICE_ID_1, TEST_SERVICE_1, setOf(TEST_SUBTYPE))
+        val query = makeQuery(TYPE_PTR to arrayOf("_testservice", "_tcp", "local"))
+
+        val srcIpv6 = InetSocketAddress(parseNumericAddress("2001:db8::123"), 5353)
+        val replyIpv6 = repository.getReply(query, srcIpv6)
+
+        assertNotNull(replyIpv6)
+        assertEquals(MdnsConstants.getMdnsIPv6Address(), replyIpv6.destination.address)
+        assertEquals(MdnsConstants.MDNS_PORT, replyIpv6.destination.port)
+    }
+
+    @Test
     fun testGetConflictingServices() {
         val repository = MdnsRecordRepository(thread.looper, deps, TEST_HOSTNAME, flags)
         repository.addService(TEST_SERVICE_ID_1, TEST_SERVICE_1)