[Feature sync] Fix issue where multiple SRV records with same host are not fully resolved
For Matter, a device may have a single host with multiple A/AAAA
records, but multiple PTR/SRV pairs that represent different
operational identities for the same device.
Currently, MdnsResponseDecoder looks for only a single matching
MdnsResponse by hostname when looping through the A/AAAA records
(which will leave the second response incomplete). Updated with a
flag that will allow returning all MdnsResponses which match the
given hostname and update the Inet records for all responses.
Bug: 254155029
Test: atest FrameworksNetTests
Verified with a Matter device with two identities that the
second response is incomplete without this change.
Additionally, added unit tests to verify the before and
after behavior with a real packet capture from the device.
Change-Id: Ic4a101b305c039f6cd7fd557246a2bfdaf0c781a
diff --git a/service/mdns/com/android/server/connectivity/mdns/MdnsConfigs.java b/service/mdns/com/android/server/connectivity/mdns/MdnsConfigs.java
index 41abba7..75c7e6c 100644
--- a/service/mdns/com/android/server/connectivity/mdns/MdnsConfigs.java
+++ b/service/mdns/com/android/server/connectivity/mdns/MdnsConfigs.java
@@ -101,4 +101,8 @@
public static boolean allowNetworkInterfaceIndexPropagation() {
return true;
}
+
+ public static boolean allowMultipleSrvRecordsPerHost() {
+ return true;
+ }
}
\ No newline at end of file
diff --git a/service/mdns/com/android/server/connectivity/mdns/MdnsResponseDecoder.java b/service/mdns/com/android/server/connectivity/mdns/MdnsResponseDecoder.java
index 57b241e..e73de55 100644
--- a/service/mdns/com/android/server/connectivity/mdns/MdnsResponseDecoder.java
+++ b/service/mdns/com/android/server/connectivity/mdns/MdnsResponseDecoder.java
@@ -25,6 +25,7 @@
import java.io.EOFException;
import java.io.IOException;
import java.net.DatagramPacket;
+import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
@@ -37,6 +38,8 @@
public static final int SUCCESS = 0;
private static final String TAG = "MdnsResponseDecoder";
private static final MdnsLogger LOGGER = new MdnsLogger(TAG);
+ private final boolean allowMultipleSrvRecordsPerHost =
+ MdnsConfigs.allowMultipleSrvRecordsPerHost();
private final String[] serviceType;
private final Clock clock;
@@ -281,13 +284,18 @@
for (MdnsRecord record : records) {
if (record instanceof MdnsInetAddressRecord) {
MdnsInetAddressRecord inetRecord = (MdnsInetAddressRecord) record;
- MdnsResponse response = findResponseWithHostName(responses, inetRecord.getName());
- if (inetRecord.getInet4Address() != null && response != null) {
- response.setInet4AddressRecord(inetRecord);
- response.setInterfaceIndex(interfaceIndex);
- } else if (inetRecord.getInet6Address() != null && response != null) {
- response.setInet6AddressRecord(inetRecord);
- response.setInterfaceIndex(interfaceIndex);
+ if (allowMultipleSrvRecordsPerHost) {
+ List<MdnsResponse> matchingResponses =
+ findResponsesWithHostName(responses, inetRecord.getName());
+ for (MdnsResponse response : matchingResponses) {
+ assignInetRecord(response, inetRecord, interfaceIndex);
+ }
+ } else {
+ MdnsResponse response =
+ findResponseWithHostName(responses, inetRecord.getName());
+ if (response != null) {
+ assignInetRecord(response, inetRecord, interfaceIndex);
+ }
}
}
}
@@ -295,6 +303,39 @@
return SUCCESS;
}
+ private static void assignInetRecord(
+ MdnsResponse response, MdnsInetAddressRecord inetRecord, int interfaceIndex) {
+ if (inetRecord.getInet4Address() != null) {
+ response.setInet4AddressRecord(inetRecord);
+ response.setInterfaceIndex(interfaceIndex);
+ } else if (inetRecord.getInet6Address() != null) {
+ response.setInet6AddressRecord(inetRecord);
+ response.setInterfaceIndex(interfaceIndex);
+ }
+ }
+
+ private static List<MdnsResponse> findResponsesWithHostName(
+ @Nullable List<MdnsResponse> responses, String[] hostName) {
+ if (responses == null || responses.isEmpty()) {
+ return List.of();
+ }
+
+ List<MdnsResponse> result = null;
+ for (MdnsResponse response : responses) {
+ MdnsServiceRecord serviceRecord = response.getServiceRecord();
+ if (serviceRecord == null) {
+ continue;
+ }
+ if (Arrays.equals(serviceRecord.getServiceHost(), hostName)) {
+ if (result == null) {
+ result = new ArrayList<>(/* initialCapacity= */ responses.size());
+ }
+ result.add(response);
+ }
+ }
+ return result == null ? List.of() : result;
+ }
+
public static class Clock {
public long elapsedRealtime() {
return SystemClock.elapsedRealtime();
diff --git a/tests/unit/java/com/android/server/connectivity/mdns/MdnsResponseDecoderTests.java b/tests/unit/java/com/android/server/connectivity/mdns/MdnsResponseDecoderTests.java
index 8d0ace5..02e00c2 100644
--- a/tests/unit/java/com/android/server/connectivity/mdns/MdnsResponseDecoderTests.java
+++ b/tests/unit/java/com/android/server/connectivity/mdns/MdnsResponseDecoderTests.java
@@ -26,11 +26,14 @@
import static org.junit.Assert.assertTrue;
import static org.mockito.Mockito.mock;
+import android.net.InetAddresses;
+
import com.android.net.module.util.HexDump;
import com.android.testutils.DevSdkIgnoreRule;
import com.android.testutils.DevSdkIgnoreRunner;
import org.junit.Before;
+import org.junit.Ignore;
import org.junit.Test;
import org.junit.runner.RunWith;
@@ -106,9 +109,49 @@
+ "63616C0000018001000000780004C0A8010A000001800100000078"
+ "0004C0A8010A00000000000000");
+ // Expected to contain two SRV records which point to the same hostname.
+ private static final byte[] matterDuplicateHostname = HexDump.hexStringToByteArray(
+ "00008000000000080000000A095F7365727669636573075F646E732D73"
+ + "64045F756470056C6F63616C00000C000100000078000F075F6D61"
+ + "74746572045F746370C023C00C000C000100000078001A125F4943"
+ + "324639453337374632454139463430045F737562C034C034000C00"
+ + "0100000078002421433246394533373746324541394634302D3030"
+ + "3030303030304534443041334641C034C04F000C00010000007800"
+ + "02C075C00C000C0001000000780002C034C00C000C000100000078"
+ + "0015125F4941413035363731333439334135343144C062C034000C"
+ + "000100000078002421414130353637313334393341353431442D30"
+ + "303030303030304331324446303344C034C0C1000C000100000078"
+ + "0002C0E2C075002100010000007800150000000015A40C33433631"
+ + "3035304338394638C023C07500100001000011940015084352493D"
+ + "35303030074352413D33303003543D31C126001C00010000007800"
+ + "10FE800000000000003E6105FFFE0C89F8C126001C000100000078"
+ + "00102605A601A84657003E6105FFFE0C89F8C12600010001000000"
+ + "780004C0A8018AC0E2002100010000007800080000000015A4C126"
+ + "C0E200100001000011940015084352493D35303030074352413D33"
+ + "303003543D31C126001C0001000000780010FE800000000000003E"
+ + "6105FFFE0C89F8C126001C00010000007800102605A601A8465700"
+ + "3E6105FFFE0C89F8C12600010001000000780004C0A8018A313035"
+ + "304338394638C02300010001000000780004C0A8018AC0A0001000"
+ + "0100001194003A0E56503D36353532312B3332373639084352493D"
+ + "35303030074352413D33303003543D3106443D3236353704434D3D"
+ + "320550483D33360350493D21433246394533373746324541394634"
+ + "302D30303030303030304534443041334641C0F700210001000000"
+ + "7800150000000015A40C334336313035304338394638C023214332"
+ + "46394533373746324541394634302D303030303030303045344430"
+ + "41334641C0F700100001000011940015084352493D353030300743"
+ + "52413D33303003543D310C334336313035304338394638C023001C"
+ + "0001000000780010FE800000000000003E6105FFFE0C89F80C3343"
+ + "36313035304338394638C023001C00010000007800102605A601A8"
+ + "4657003E6105FFFE0C89F80C334336313035304338394638C02300"
+ + "010001000000780004C0A8018A0000000000000000000000000000"
+ + "000000");
+
private static final String CAST_SERVICE_NAME = "_googlecast";
private static final String[] CAST_SERVICE_TYPE =
new String[] {CAST_SERVICE_NAME, "_tcp", "local"};
+ private static final String MATTER_SERVICE_NAME = "_matter";
+ private static final String[] MATTER_SERVICE_TYPE =
+ new String[] {MATTER_SERVICE_NAME, "_tcp", "local"};
private final List<MdnsResponse> responses = new LinkedList<>();
@@ -249,4 +292,62 @@
assertEquals(responses.size(), 1);
assertEquals(responses.get(0).getInterfaceIndex(), 10);
}
+
+ @Test
+ public void decode_singleHostname_multipleSrvRecords_flagEnabled_multipleCompleteResponses() {
+ //MdnsScannerConfigsFlagsImpl.allowMultipleSrvRecordsPerHost.override(true);
+ MdnsResponseDecoder decoder = new MdnsResponseDecoder(mClock, MATTER_SERVICE_TYPE);
+ assertNotNull(matterDuplicateHostname);
+
+ DatagramPacket packet =
+ new DatagramPacket(matterDuplicateHostname, matterDuplicateHostname.length);
+
+ packet.setSocketAddress(
+ new InetSocketAddress(MdnsConstants.getMdnsIPv6Address(), MdnsConstants.MDNS_PORT));
+
+ responses.clear();
+ int errorCode = decoder.decode(packet, responses, /* interfaceIndex= */ 0);
+ assertEquals(MdnsResponseDecoder.SUCCESS, errorCode);
+
+ // This should emit two records:
+ assertEquals(2, responses.size());
+
+ MdnsResponse response1 = responses.get(0);
+ MdnsResponse response2 = responses.get(0);
+
+ // Both of which are complete:
+ assertTrue(response1.isComplete());
+ assertTrue(response2.isComplete());
+
+ // And should both have the same IPv6 address:
+ assertEquals(InetAddresses.parseNumericAddress("2605:a601:a846:5700:3e61:5ff:fe0c:89f8"),
+ response1.getInet6AddressRecord().getInet6Address());
+ assertEquals(InetAddresses.parseNumericAddress("2605:a601:a846:5700:3e61:5ff:fe0c:89f8"),
+ response2.getInet6AddressRecord().getInet6Address());
+ }
+
+ @Test
+ @Ignore("MdnsConfigs is not configurable currently.")
+ public void decode_singleHostname_multipleSrvRecords_flagDisabled_singleCompleteResponse() {
+ //MdnsScannerConfigsFlagsImpl.allowMultipleSrvRecordsPerHost.override(false);
+ MdnsResponseDecoder decoder = new MdnsResponseDecoder(mClock, MATTER_SERVICE_TYPE);
+ assertNotNull(matterDuplicateHostname);
+
+ DatagramPacket packet =
+ new DatagramPacket(matterDuplicateHostname, matterDuplicateHostname.length);
+
+ packet.setSocketAddress(
+ new InetSocketAddress(MdnsConstants.getMdnsIPv6Address(), MdnsConstants.MDNS_PORT));
+
+ responses.clear();
+ int errorCode = decoder.decode(packet, responses, /* interfaceIndex= */ 0);
+ assertEquals(MdnsResponseDecoder.SUCCESS, errorCode);
+
+ // This should emit only two records:
+ assertEquals(2, responses.size());
+
+ // But only the first is complete:
+ assertTrue(responses.get(0).isComplete());
+ assertFalse(responses.get(1).isComplete());
+ }
}
\ No newline at end of file