Merge "Store transaction id in MdnsPacket" into main

service-t/src/com/android/server/connectivity/mdns/MdnsPacket.java

@@ -31,6 +31,7 @@ import java.util.List;
 public class MdnsPacket {
     private static final String TAG = MdnsPacket.class.getSimpleName();
 
+    public final int transactionId;
     public final int flags;
     @NonNull
     public final List<MdnsRecord> questions;
@@ -46,6 +47,15 @@ public class MdnsPacket {
             @NonNull List<MdnsRecord> answers,
             @NonNull List<MdnsRecord> authorityRecords,
             @NonNull List<MdnsRecord> additionalRecords) {
+        this(0, flags, questions, answers, authorityRecords, additionalRecords);
+    }
+
+    MdnsPacket(int transactionId, int flags,
+            @NonNull List<MdnsRecord> questions,
+            @NonNull List<MdnsRecord> answers,
+            @NonNull List<MdnsRecord> authorityRecords,
+            @NonNull List<MdnsRecord> additionalRecords) {
+        this.transactionId = transactionId;
         this.flags = flags;
         this.questions = Collections.unmodifiableList(questions);
         this.answers = Collections.unmodifiableList(answers);
@@ -70,15 +80,16 @@ public class MdnsPacket {
      */
     @NonNull
     public static MdnsPacket parse(@NonNull MdnsPacketReader reader) throws ParseException {
+        final int transactionId;
         final int flags;
         try {
-            reader.readUInt16(); // transaction ID (not used)
+            transactionId = reader.readUInt16();
             flags = reader.readUInt16();
         } catch (EOFException e) {
             throw new ParseException(MdnsResponseErrorCode.ERROR_END_OF_FILE,
                     "Reached the end of the mDNS response unexpectedly.", e);
         }
-        return parseRecordsSection(reader, flags);
+        return parseRecordsSection(reader, flags, transactionId);
     }
 
     /**
@@ -86,8 +97,8 @@ public class MdnsPacket {
      *
      * The records section starts with the questions count, just after the packet flags.
      */
-    public static MdnsPacket parseRecordsSection(@NonNull MdnsPacketReader reader, int flags)
-            throws ParseException {
+    public static MdnsPacket parseRecordsSection(@NonNull MdnsPacketReader reader, int flags,
+            int transactionId) throws ParseException {
         try {
             final int numQuestions = reader.readUInt16();
             final int numAnswers = reader.readUInt16();
@@ -99,7 +110,7 @@ public class MdnsPacket {
             final ArrayList<MdnsRecord> authority = parseRecords(reader, numAuthority, false);
             final ArrayList<MdnsRecord> additional = parseRecords(reader, numAdditional, false);
 
-            return new MdnsPacket(flags, questions, answers, authority, additional);
+            return new MdnsPacket(transactionId, flags, questions, answers, authority, additional);
         } catch (EOFException e) {
             throw new ParseException(MdnsResponseErrorCode.ERROR_END_OF_FILE,
                     "Reached the end of the mDNS response unexpectedly.", e);

service-t/src/com/android/server/connectivity/mdns/MdnsResponseDecoder.java

@@ -90,14 +90,14 @@ public class MdnsResponseDecoder {
 
         final MdnsPacket mdnsPacket;
         try {
-            reader.readUInt16(); // transaction ID (not used)
+            final int transactionId = reader.readUInt16();
             int flags = reader.readUInt16();
             if ((flags & MdnsConstants.FLAGS_RESPONSE_MASK) != MdnsConstants.FLAGS_RESPONSE) {
                 throw new MdnsPacket.ParseException(
                         MdnsResponseErrorCode.ERROR_NOT_RESPONSE_MESSAGE, "Not a response", null);
             }
 
-            mdnsPacket = MdnsPacket.parseRecordsSection(reader, flags);
+            mdnsPacket = MdnsPacket.parseRecordsSection(reader, flags, transactionId);
             if (mdnsPacket.answers.size() < 1) {
                 throw new MdnsPacket.ParseException(
                         MdnsResponseErrorCode.ERROR_NO_ANSWERS, "Response has no answers",

service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java

@@ -189,7 +189,7 @@ public class MdnsUtils {
         // TODO: support packets over size (send in multiple packets with TC bit set)
         final MdnsPacketWriter writer = new MdnsPacketWriter(packetCreationBuffer);
 
-        writer.writeUInt16(0); // Transaction ID (advertisement: 0)
+        writer.writeUInt16(packet.transactionId); // Transaction ID (advertisement: 0)
         writer.writeUInt16(packet.flags); // Response, authoritative (rfc6762 18.4)
         writer.writeUInt16(packet.questions.size()); // questions count
         writer.writeUInt16(packet.answers.size()); // answers count

tests/unit/java/com/android/server/connectivity/mdns/MdnsPacketTest.kt

@@ -32,7 +32,7 @@ class MdnsPacketTest {
         // Probe packet with 1 question for Android.local, and 4 additionalRecords with 4 addresses
         // for Android.local (similar to legacy mdnsresponder probes, although it used to put 4
         // identical questions(!!) for Android.local when there were 4 addresses).
-        val packetHex = "00000000000100000004000007416e64726f6964056c6f63616c0000ff0001c00c000100" +
+        val packetHex = "007b0000000100000004000007416e64726f6964056c6f63616c0000ff0001c00c000100" +
                 "01000000780004c000027bc00c001c000100000078001020010db8000000000000000000000123c0" +
                 "0c001c000100000078001020010db8000000000000000000000456c00c001c000100000078001020" +
                 "010db8000000000000000000000789"
@@ -41,6 +41,7 @@ class MdnsPacketTest {
         val reader = MdnsPacketReader(bytes, bytes.size)
         val packet = MdnsPacket.parse(reader)
 
+        assertEquals(123, packet.transactionId)
         assertEquals(1, packet.questions.size)
         assertEquals(0, packet.answers.size)
         assertEquals(4, packet.authorityRecords.size)

tests/unit/java/com/android/server/connectivity/mdns/MdnsRecordRepositoryTest.kt

@@ -105,6 +105,7 @@ class MdnsRecordRepositoryTest {
         assertEquals(TEST_SERVICE_ID_1, probingInfo.serviceId)
         val packet = probingInfo.getPacket(0)
 
+        assertEquals(0, packet.transactionId)
         assertEquals(MdnsConstants.FLAGS_QUERY, packet.flags)
         assertEquals(0, packet.answers.size)
         assertEquals(0, packet.additionalRecords.size)
@@ -173,6 +174,7 @@ class MdnsRecordRepositoryTest {
         assertEquals(1, repository.servicesCount)
         val packet = exitAnnouncement.getPacket(0)
 
+        assertEquals(0, packet.transactionId)
         assertEquals(0x8400 /* response, authoritative */, packet.flags)
         assertEquals(0, packet.questions.size)
         assertEquals(0, packet.authorityRecords.size)
@@ -202,6 +204,7 @@ class MdnsRecordRepositoryTest {
         assertEquals(1, repository.servicesCount)
         val packet = exitAnnouncement.getPacket(0)
 
+        assertEquals(0, packet.transactionId)
         assertEquals(0x8400 /* response, authoritative */, packet.flags)
         assertEquals(0, packet.questions.size)
         assertEquals(0, packet.authorityRecords.size)
@@ -249,6 +252,7 @@ class MdnsRecordRepositoryTest {
         repository.onAdvertisementSent(TEST_SERVICE_ID_1, 2 /* sentPacketCount */)
         val packet = announcementInfo.getPacket(0)
 
+        assertEquals(0, packet.transactionId)
         assertEquals(0x8400 /* response, authoritative */, packet.flags)
         assertEquals(0, packet.questions.size)
         assertEquals(0, packet.authorityRecords.size)
@@ -372,6 +376,7 @@ class MdnsRecordRepositoryTest {
         val serviceName = arrayOf("MyTestService", "_testservice", "_tcp", "local")
         val serviceType = arrayOf("_testservice", "_tcp", "local")
         val offloadPacket = repository.getOffloadPacket(TEST_SERVICE_ID_1)
+        assertEquals(0, offloadPacket.transactionId)
         assertEquals(0x8400, offloadPacket.flags)
         assertEquals(0, offloadPacket.questions.size)
         assertEquals(0, offloadPacket.additionalRecords.size)