Renew the SRV/TXT records if half of TTL passed
As mentioned in RFC6762 7.1. The records only needed to be renewed if
at least half of the TTL passed. Usually A/AAAA records are included in
the response to the SRV record query, they are not refreshed individually.
Bug: 285260665
Bug: 285261577
Test: atest CtsNetTest FrameworksNetTests
(cherry picked from https://android-review.googlesource.com/q/commit:f2cc01dc126ba1bd8c89add0853546ab4627c3aa)
Merged-In: Ifd7140de0d733191256184c5481412e1822d279b
Change-Id: Ifd7140de0d733191256184c5481412e1822d279b
diff --git a/service-t/src/com/android/server/connectivity/mdns/EnqueueMdnsQueryCallable.java b/service-t/src/com/android/server/connectivity/mdns/EnqueueMdnsQueryCallable.java
index 866ecba..84faf12 100644
--- a/service-t/src/com/android/server/connectivity/mdns/EnqueueMdnsQueryCallable.java
+++ b/service-t/src/com/android/server/connectivity/mdns/EnqueueMdnsQueryCallable.java
@@ -24,6 +24,7 @@
import android.util.Pair;
import com.android.server.connectivity.mdns.util.MdnsLogger;
+import com.android.server.connectivity.mdns.util.MdnsUtils;
import java.io.IOException;
import java.lang.ref.WeakReference;
@@ -75,6 +76,8 @@
private final boolean sendDiscoveryQueries;
@NonNull
private final List<MdnsResponse> servicesToResolve;
+ @NonNull
+ private final MdnsResponseDecoder.Clock clock;
EnqueueMdnsQueryCallable(
@NonNull MdnsSocketClientBase requestSender,
@@ -85,7 +88,8 @@
int transactionId,
@Nullable Network network,
boolean sendDiscoveryQueries,
- @NonNull Collection<MdnsResponse> servicesToResolve) {
+ @NonNull Collection<MdnsResponse> servicesToResolve,
+ @NonNull MdnsResponseDecoder.Clock clock) {
weakRequestSender = new WeakReference<>(requestSender);
this.packetWriter = packetWriter;
serviceTypeLabels = TextUtils.split(serviceType, "\\.");
@@ -95,6 +99,7 @@
this.network = network;
this.sendDiscoveryQueries = sendDiscoveryQueries;
this.servicesToResolve = new ArrayList<>(servicesToResolve);
+ this.clock = clock;
}
// Incompatible return type for override of Callable#call().
@@ -119,22 +124,24 @@
// List of (name, type) to query
final ArrayList<Pair<String[], Integer>> missingKnownAnswerRecords = new ArrayList<>();
+ final long now = clock.elapsedRealtime();
for (MdnsResponse response : servicesToResolve) {
- // TODO: also send queries to renew record TTL (as per RFC6762 7.1 no need to query
- // if remaining TTL is more than half the original one, so send the queries if half
- // the TTL has passed).
- if (response.isComplete()) continue;
final String[] serviceName = response.getServiceName();
if (serviceName == null) continue;
- if (!response.hasTextRecord()) {
+ if (!response.hasTextRecord() || MdnsUtils.isRecordRenewalNeeded(
+ response.getTextRecord(), now)) {
missingKnownAnswerRecords.add(new Pair<>(serviceName, MdnsRecord.TYPE_TXT));
}
- if (!response.hasServiceRecord()) {
+ if (!response.hasServiceRecord() || MdnsUtils.isRecordRenewalNeeded(
+ response.getServiceRecord(), now)) {
missingKnownAnswerRecords.add(new Pair<>(serviceName, MdnsRecord.TYPE_SRV));
// The hostname is not yet known, so queries for address records will be sent
// the next time the EnqueueMdnsQueryCallable is enqueued if the reply does not
// contain them. In practice, advertisers should include the address records
// when queried for SRV, although it's not a MUST requirement (RFC6763 12.2).
+ // TODO: Figure out how to renew the A/AAAA record. Usually A/AAAA record will
+ // be included in the response to the SRV record so in high chances there is
+ // no need to renew them individually.
} else if (!response.hasInet4AddressRecord() && !response.hasInet6AddressRecord()) {
final String[] host = response.getServiceRecord().getServiceHost();
missingKnownAnswerRecords.add(new Pair<>(host, MdnsRecord.TYPE_A));
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsServiceTypeClient.java b/service-t/src/com/android/server/connectivity/mdns/MdnsServiceTypeClient.java
index d7eaea5..809750d 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsServiceTypeClient.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsServiceTypeClient.java
@@ -532,7 +532,8 @@
config.transactionId,
config.network,
sendDiscoveryQueries,
- servicesToResolve)
+ servicesToResolve,
+ clock)
.call();
} catch (RuntimeException e) {
sharedLog.e(String.format("Failed to run EnqueueMdnsQueryCallable for subtype: %s",
diff --git a/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java b/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java
index 5413956..3added6 100644
--- a/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java
+++ b/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java
@@ -108,4 +108,15 @@
encoder.encode(CharBuffer.wrap(originalName), out, true /* endOfInput */);
return new String(out.array(), 0, out.position(), utf8);
}
+
+ /**
+ * Checks if the MdnsRecord needs to be renewed or not.
+ *
+ * <p>As per RFC6762 7.1 no need to query if remaining TTL is more than half the original one,
+ * so send the queries if half the TTL has passed.
+ */
+ public static boolean isRecordRenewalNeeded(@NonNull MdnsRecord mdnsRecord, final long now) {
+ return mdnsRecord.getTtl() > 0
+ && mdnsRecord.getRemainingTTL(now) <= mdnsRecord.getTtl() / 2;
+ }
}
\ No newline at end of file
diff --git a/tests/unit/java/com/android/server/connectivity/mdns/MdnsServiceTypeClientTests.java b/tests/unit/java/com/android/server/connectivity/mdns/MdnsServiceTypeClientTests.java
index 43f3ace..f51079b 100644
--- a/tests/unit/java/com/android/server/connectivity/mdns/MdnsServiceTypeClientTests.java
+++ b/tests/unit/java/com/android/server/connectivity/mdns/MdnsServiceTypeClientTests.java
@@ -932,15 +932,11 @@
final MdnsPacket srvTxtQueryPacket = MdnsPacket.parse(
new MdnsPacketReader(srvTxtQueryCaptor.getValue()));
- final List<MdnsRecord> srvTxtQuestions = srvTxtQueryPacket.questions;
- final String[] serviceName = Stream.concat(Stream.of(instanceName),
- Arrays.stream(SERVICE_TYPE_LABELS)).toArray(String[]::new);
- assertFalse(srvTxtQuestions.stream().anyMatch(q -> q.getType() == MdnsRecord.TYPE_PTR));
- assertTrue(srvTxtQuestions.stream().anyMatch(q ->
- q.getType() == MdnsRecord.TYPE_SRV && Arrays.equals(q.name, serviceName)));
- assertTrue(srvTxtQuestions.stream().anyMatch(q ->
- q.getType() == MdnsRecord.TYPE_TXT && Arrays.equals(q.name, serviceName)));
+ final String[] serviceName = getTestServiceName(instanceName);
+ assertFalse(hasQuestion(srvTxtQueryPacket, MdnsRecord.TYPE_PTR));
+ assertTrue(hasQuestion(srvTxtQueryPacket, MdnsRecord.TYPE_SRV, serviceName));
+ assertTrue(hasQuestion(srvTxtQueryPacket, MdnsRecord.TYPE_TXT, serviceName));
// Process a response with SRV+TXT
final MdnsPacket srvTxtResponse = new MdnsPacket(
@@ -967,11 +963,8 @@
final MdnsPacket addressQueryPacket = MdnsPacket.parse(
new MdnsPacketReader(addressQueryCaptor.getValue()));
- final List<MdnsRecord> addressQueryQuestions = addressQueryPacket.questions;
- assertTrue(addressQueryQuestions.stream().anyMatch(q ->
- q.getType() == MdnsRecord.TYPE_A && Arrays.equals(q.name, hostname)));
- assertTrue(addressQueryQuestions.stream().anyMatch(q ->
- q.getType() == MdnsRecord.TYPE_AAAA && Arrays.equals(q.name, hostname)));
+ assertTrue(hasQuestion(addressQueryPacket, MdnsRecord.TYPE_A, hostname));
+ assertTrue(hasQuestion(addressQueryPacket, MdnsRecord.TYPE_AAAA, hostname));
// Process a response with address records
final MdnsPacket addressResponse = new MdnsPacket(
@@ -1004,6 +997,81 @@
}
@Test
+ public void testRenewTxtSrvInResolve() throws Exception {
+ client = new MdnsServiceTypeClient(SERVICE_TYPE, mockSocketClient, currentThreadExecutor,
+ mockDecoderClock, mockNetwork, mockSharedLog);
+
+ final String instanceName = "service-instance";
+ final String[] hostname = new String[] { "testhost "};
+ final String ipV4Address = "192.0.2.0";
+ final String ipV6Address = "2001:db8::";
+
+ final MdnsSearchOptions resolveOptions = MdnsSearchOptions.newBuilder()
+ .setResolveInstanceName(instanceName).build();
+
+ client.startSendAndReceive(mockListenerOne, resolveOptions);
+ InOrder inOrder = inOrder(mockListenerOne, mockSocketClient);
+
+ // Get the query for SRV/TXT
+ final ArgumentCaptor<DatagramPacket> srvTxtQueryCaptor =
+ ArgumentCaptor.forClass(DatagramPacket.class);
+ currentThreadExecutor.getAndClearLastScheduledRunnable().run();
+ // Send twice for IPv4 and IPv6
+ inOrder.verify(mockSocketClient, times(2)).sendUnicastPacket(srvTxtQueryCaptor.capture(),
+ eq(mockNetwork));
+
+ final MdnsPacket srvTxtQueryPacket = MdnsPacket.parse(
+ new MdnsPacketReader(srvTxtQueryCaptor.getValue()));
+
+ final String[] serviceName = getTestServiceName(instanceName);
+ assertTrue(hasQuestion(srvTxtQueryPacket, MdnsRecord.TYPE_SRV, serviceName));
+ assertTrue(hasQuestion(srvTxtQueryPacket, MdnsRecord.TYPE_TXT, serviceName));
+
+ // Process a response with all records
+ final MdnsPacket srvTxtResponse = new MdnsPacket(
+ 0 /* flags */,
+ Collections.emptyList() /* questions */,
+ List.of(
+ new MdnsServiceRecord(serviceName, TEST_ELAPSED_REALTIME,
+ true /* cacheFlush */, TEST_TTL, 0 /* servicePriority */,
+ 0 /* serviceWeight */, 1234 /* servicePort */, hostname),
+ new MdnsTextRecord(serviceName, TEST_ELAPSED_REALTIME,
+ true /* cacheFlush */, TEST_TTL,
+ Collections.emptyList() /* entries */),
+ new MdnsInetAddressRecord(hostname, TEST_ELAPSED_REALTIME,
+ true /* cacheFlush */, TEST_TTL,
+ InetAddresses.parseNumericAddress(ipV4Address)),
+ new MdnsInetAddressRecord(hostname, TEST_ELAPSED_REALTIME,
+ true /* cacheFlush */, TEST_TTL,
+ InetAddresses.parseNumericAddress(ipV6Address))),
+ Collections.emptyList() /* authorityRecords */,
+ Collections.emptyList() /* additionalRecords */);
+ client.processResponse(srvTxtResponse, INTERFACE_INDEX, mockNetwork);
+ inOrder.verify(mockListenerOne).onServiceNameDiscovered(any());
+ inOrder.verify(mockListenerOne).onServiceFound(any());
+
+ // Expect no query on the next run
+ currentThreadExecutor.getAndClearLastScheduledRunnable().run();
+ inOrder.verifyNoMoreInteractions();
+
+ // Advance time so 75% of TTL passes and re-execute
+ doReturn(TEST_ELAPSED_REALTIME + (long) (TEST_TTL * 0.75))
+ .when(mockDecoderClock).elapsedRealtime();
+ currentThreadExecutor.getAndClearLastScheduledRunnable().run();
+
+ // Expect a renewal query
+ final ArgumentCaptor<DatagramPacket> renewalQueryCaptor =
+ ArgumentCaptor.forClass(DatagramPacket.class);
+ // Second and later sends are sent as "expect multicast response" queries
+ inOrder.verify(mockSocketClient, times(2)).sendMulticastPacket(renewalQueryCaptor.capture(),
+ eq(mockNetwork));
+ final MdnsPacket renewalPacket = MdnsPacket.parse(
+ new MdnsPacketReader(renewalQueryCaptor.getValue()));
+ assertTrue(hasQuestion(renewalPacket, MdnsRecord.TYPE_SRV, serviceName));
+ assertTrue(hasQuestion(renewalPacket, MdnsRecord.TYPE_TXT, serviceName));
+ }
+
+ @Test
public void testProcessResponse_ResolveExcludesOtherServices() {
client = new MdnsServiceTypeClient(
SERVICE_TYPE, mockSocketClient, currentThreadExecutor, mockNetwork, mockSharedLog);
@@ -1244,6 +1312,20 @@
}
}
+ private static String[] getTestServiceName(String instanceName) {
+ return Stream.concat(Stream.of(instanceName),
+ Arrays.stream(SERVICE_TYPE_LABELS)).toArray(String[]::new);
+ }
+
+ private static boolean hasQuestion(MdnsPacket packet, int type) {
+ return hasQuestion(packet, type, null);
+ }
+
+ private static boolean hasQuestion(MdnsPacket packet, int type, @Nullable String[] name) {
+ return packet.questions.stream().anyMatch(q -> q.getType() == type
+ && (name == null || Arrays.equals(q.name, name)));
+ }
+
// A fake ScheduledExecutorService that keeps tracking the last scheduled Runnable and its delay
// time.
private class FakeExecutor extends ScheduledThreadPoolExecutor {