Store transaction id in MdnsPacket
The transaction id is a number that is used to identify a
specific query packet. But it's not necessary for probing
or announcing services, so the transaction id is not
currently used on advertising when creating a MdnsPacket or
decoding the response to a MdnsPacket. This means that it is not
possible to track which query packets have received
responses. Therefore, store the transaction id so that
it can be used for subsequent query packet changes.
Bug: 302269599
Test: atest FrameworksNetTests
Change-Id: I6734752b32b91678afb7df06e1fa51237cf70894
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsPacket.java b/service-t/src/com/android/server/connectivity/mdns/MdnsPacket.java
index 7fa3f84..1fabd49 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsPacket.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsPacket.java
@@ -31,6 +31,7 @@
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 @@
@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 @@
*/
@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 @@
*
* 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 @@
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);
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsResponseDecoder.java b/service-t/src/com/android/server/connectivity/mdns/MdnsResponseDecoder.java
index a3cc0eb..050913f 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsResponseDecoder.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsResponseDecoder.java
@@ -90,14 +90,14 @@
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",
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 0dcc560..d0f3d9a 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
@@ -189,7 +189,7 @@
// 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
diff --git a/tests/unit/java/com/android/server/connectivity/mdns/MdnsPacketTest.kt b/tests/unit/java/com/android/server/connectivity/mdns/MdnsPacketTest.kt
index b667e5f..28ea4b6 100644
--- a/tests/unit/java/com/android/server/connectivity/mdns/MdnsPacketTest.kt
+++ b/tests/unit/java/com/android/server/connectivity/mdns/MdnsPacketTest.kt
@@ -32,7 +32,7 @@
// 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 @@
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)
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 88fb66a..c9b502e 100644
--- a/tests/unit/java/com/android/server/connectivity/mdns/MdnsRecordRepositoryTest.kt
+++ b/tests/unit/java/com/android/server/connectivity/mdns/MdnsRecordRepositoryTest.kt
@@ -105,6 +105,7 @@
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 @@
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 @@
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 @@
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 @@
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)