From 24db3f1e1df4d90c0df777a6f7f124b4039fc030 Mon Sep 17 00:00:00 2001
From: Paul Hu <paulhu@google.com>
Date: Thu, 23 Nov 2023 04:00:26 +0000
Subject: [PATCH] Generate a query packet with MdnsPacket
This is a no-op change, only refactoring the query packet
generation code to use MdnsPacket. This refactoring enables the
insertion of additional sections into the query packet and
facilitates the determination of truncation requirements.
Bug: 312657709
Test: atest FrameworksNetTests NsdManagerTest
Change-Id: I3671842b6d433e1856a1efae643f3fe1f6c532d1
---
.../mdns/EnqueueMdnsQueryCallable.java | 75 +++++++------------
.../mdns/MdnsInetAddressRecord.java | 6 ++
.../connectivity/mdns/MdnsPointerRecord.java | 6 ++
.../connectivity/mdns/MdnsServiceRecord.java | 6 ++
.../connectivity/mdns/MdnsTextRecord.java | 6 ++
.../connectivity/mdns/util/MdnsUtils.java | 19 +++--
6 files changed, 64 insertions(+), 54 deletions(-)
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 1582fb66b4..c4d3338ed2 100644
--- a/service-t/src/com/android/server/connectivity/mdns/EnqueueMdnsQueryCallable.java
+++ b/service-t/src/com/android/server/connectivity/mdns/EnqueueMdnsQueryCallable.java
@@ -32,6 +32,7 @@ import java.net.DatagramPacket;
import java.net.InetSocketAddress;
import java.util.ArrayList;
import java.util.Collection;
+import java.util.Collections;
import java.util.List;
import java.util.concurrent.Callable;
@@ -122,17 +123,22 @@ public class EnqueueMdnsQueryCallable implements Callable<Pair<Integer, List<Str
return Pair.create(INVALID_TRANSACTION_ID, new ArrayList<>());
}
- int numQuestions = 0;
+ final List<MdnsRecord> questions = new ArrayList<>();
if (sendDiscoveryQueries) {
- numQuestions++; // Base service type
- if (!subtypes.isEmpty()) {
- numQuestions += subtypes.size();
+ // Base service type
+ questions.add(new MdnsPointerRecord(serviceTypeLabels, expectUnicastResponse));
+ for (String subtype : subtypes) {
+ final String[] labels = new String[serviceTypeLabels.length + 2];
+ labels[0] = MdnsConstants.SUBTYPE_PREFIX + subtype;
+ labels[1] = MdnsConstants.SUBTYPE_LABEL;
+ System.arraycopy(serviceTypeLabels, 0, labels, 2, serviceTypeLabels.length);
+
+ questions.add(new MdnsPointerRecord(labels, expectUnicastResponse));
}
}
// List of (name, type) to query
- final ArrayList<Pair<String[], Integer>> missingKnownAnswerRecords = new ArrayList<>();
final long now = clock.elapsedRealtime();
for (MdnsResponse response : servicesToResolve) {
final String[] serviceName = response.getServiceName();
@@ -142,13 +148,13 @@ public class EnqueueMdnsQueryCallable implements Callable<Pair<Integer, List<Str
boolean renewSrv = !response.hasServiceRecord() || MdnsUtils.isRecordRenewalNeeded(
response.getServiceRecord(), now);
if (renewSrv && renewTxt) {
- missingKnownAnswerRecords.add(new Pair<>(serviceName, MdnsRecord.TYPE_ANY));
+ questions.add(new MdnsAnyRecord(serviceName, expectUnicastResponse));
} else {
if (renewTxt) {
- missingKnownAnswerRecords.add(new Pair<>(serviceName, MdnsRecord.TYPE_TXT));
+ questions.add(new MdnsTextRecord(serviceName, expectUnicastResponse));
}
if (renewSrv) {
- missingKnownAnswerRecords.add(new Pair<>(serviceName, MdnsRecord.TYPE_SRV));
+ questions.add(new MdnsServiceRecord(serviceName, expectUnicastResponse));
// 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
@@ -157,46 +163,27 @@ public class EnqueueMdnsQueryCallable implements Callable<Pair<Integer, List<Str
} else if (!response.hasInet4AddressRecord()
&& !response.hasInet6AddressRecord()) {
final String[] host = response.getServiceRecord().getServiceHost();
- missingKnownAnswerRecords.add(new Pair<>(host, MdnsRecord.TYPE_A));
- missingKnownAnswerRecords.add(new Pair<>(host, MdnsRecord.TYPE_AAAA));
+ questions.add(new MdnsInetAddressRecord(
+ host, MdnsRecord.TYPE_A, expectUnicastResponse));
+ questions.add(new MdnsInetAddressRecord(
+ host, MdnsRecord.TYPE_AAAA, expectUnicastResponse));
}
}
}
- numQuestions += missingKnownAnswerRecords.size();
- if (numQuestions == 0) {
+ if (questions.size() == 0) {
// No query to send
return Pair.create(INVALID_TRANSACTION_ID, new ArrayList<>());
}
- // Header.
- packetWriter.writeUInt16(transactionId); // transaction ID
- packetWriter.writeUInt16(MdnsConstants.FLAGS_QUERY); // flags
- packetWriter.writeUInt16(numQuestions); // number of questions
- packetWriter.writeUInt16(0); // number of answers (not yet known; will be written later)
- packetWriter.writeUInt16(0); // number of authority entries
- packetWriter.writeUInt16(0); // number of additional records
-
- // Question(s) for missing records on known answers
- for (Pair<String[], Integer> question : missingKnownAnswerRecords) {
- writeQuestion(question.first, question.second);
- }
-
- // Question(s) for discovering other services with the type. There will be one question
- // for each (fqdn+subtype, recordType) combination, as well as one for each (fqdn,
- // recordType) combination.
- if (sendDiscoveryQueries) {
- for (String subtype : subtypes) {
- String[] labels = new String[serviceTypeLabels.length + 2];
- labels[0] = MdnsConstants.SUBTYPE_PREFIX + subtype;
- labels[1] = MdnsConstants.SUBTYPE_LABEL;
- System.arraycopy(serviceTypeLabels, 0, labels, 2, serviceTypeLabels.length);
-
- writeQuestion(labels, MdnsRecord.TYPE_PTR);
- }
- writeQuestion(serviceTypeLabels, MdnsRecord.TYPE_PTR);
- }
-
+ final MdnsPacket queryPacket = new MdnsPacket(
+ transactionId,
+ MdnsConstants.FLAGS_QUERY,
+ questions,
+ Collections.emptyList(), /* answers */
+ Collections.emptyList(), /* authorityRecords */
+ Collections.emptyList() /* additionalRecords */);
+ MdnsUtils.writeMdnsPacket(packetWriter, queryPacket);
sendPacketToIpv4AndIpv6(requestSender, MdnsConstants.MDNS_PORT);
for (Integer emulatorPort : castShellEmulatorMdnsPorts) {
sendPacketToIpv4AndIpv6(requestSender, emulatorPort);
@@ -209,14 +196,6 @@ public class EnqueueMdnsQueryCallable implements Callable<Pair<Integer, List<Str
}
}
- private void writeQuestion(String[] labels, int type) throws IOException {
- packetWriter.writeLabels(labels);
- packetWriter.writeUInt16(type);
- packetWriter.writeUInt16(
- MdnsConstants.QCLASS_INTERNET
- | (expectUnicastResponse ? MdnsConstants.QCLASS_UNICAST : 0));
- }
-
private void sendPacket(MdnsSocketClientBase requestSender, InetSocketAddress address)
throws IOException {
DatagramPacket packet = packetWriter.getPacket(address);
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsInetAddressRecord.java b/service-t/src/com/android/server/connectivity/mdns/MdnsInetAddressRecord.java
index 973fd9602e..4399f2d6da 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsInetAddressRecord.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsInetAddressRecord.java
@@ -60,6 +60,12 @@ public class MdnsInetAddressRecord extends MdnsRecord {
super(name, type, reader, isQuestion);
}
+ public MdnsInetAddressRecord(String[] name, int type, boolean isUnicast) {
+ super(name, type,
+ MdnsConstants.QCLASS_INTERNET | (isUnicast ? MdnsConstants.QCLASS_UNICAST : 0),
+ 0L /* receiptTimeMillis */, false /* cacheFlush */, 0L /* ttlMillis */);
+ }
+
public MdnsInetAddressRecord(String[] name, long receiptTimeMillis, boolean cacheFlush,
long ttlMillis, InetAddress address) {
super(name, address instanceof Inet4Address ? TYPE_A : TYPE_AAAA,
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsPointerRecord.java b/service-t/src/com/android/server/connectivity/mdns/MdnsPointerRecord.java
index 41cc380029..e5c90a46e8 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsPointerRecord.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsPointerRecord.java
@@ -39,6 +39,12 @@ public class MdnsPointerRecord extends MdnsRecord {
super(name, TYPE_PTR, reader, isQuestion);
}
+ public MdnsPointerRecord(String[] name, boolean isUnicast) {
+ super(name, TYPE_PTR,
+ MdnsConstants.QCLASS_INTERNET | (isUnicast ? MdnsConstants.QCLASS_UNICAST : 0),
+ 0L /* receiptTimeMillis */, false /* cacheFlush */, 0L /* ttlMillis */);
+ }
+
public MdnsPointerRecord(String[] name, long receiptTimeMillis, boolean cacheFlush,
long ttlMillis, String[] pointer) {
super(name, TYPE_PTR, MdnsConstants.QCLASS_INTERNET, receiptTimeMillis, cacheFlush,
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsServiceRecord.java b/service-t/src/com/android/server/connectivity/mdns/MdnsServiceRecord.java
index 4d407be63f..0d6a9ec487 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsServiceRecord.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsServiceRecord.java
@@ -49,6 +49,12 @@ public class MdnsServiceRecord extends MdnsRecord {
super(name, TYPE_SRV, reader, isQuestion);
}
+ public MdnsServiceRecord(String[] name, boolean isUnicast) {
+ super(name, TYPE_SRV,
+ MdnsConstants.QCLASS_INTERNET | (isUnicast ? MdnsConstants.QCLASS_UNICAST : 0),
+ 0L /* receiptTimeMillis */, false /* cacheFlush */, 0L /* ttlMillis */);
+ }
+
public MdnsServiceRecord(String[] name, long receiptTimeMillis, boolean cacheFlush,
long ttlMillis, int servicePriority, int serviceWeight, int servicePort,
String[] serviceHost) {
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsTextRecord.java b/service-t/src/com/android/server/connectivity/mdns/MdnsTextRecord.java
index cf6c8acf2f..92cf3243cc 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsTextRecord.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsTextRecord.java
@@ -42,6 +42,12 @@ public class MdnsTextRecord extends MdnsRecord {
super(name, TYPE_TXT, reader, isQuestion);
}
+ public MdnsTextRecord(String[] name, boolean isUnicast) {
+ super(name, TYPE_TXT,
+ MdnsConstants.QCLASS_INTERNET | (isUnicast ? MdnsConstants.QCLASS_UNICAST : 0),
+ 0L /* receiptTimeMillis */, false /* cacheFlush */, 0L /* ttlMillis */);
+ }
+
public MdnsTextRecord(String[] name, long receiptTimeMillis, boolean cacheFlush, long ttlMillis,
List<TextEntry> entries) {
super(name, TYPE_TXT, MdnsConstants.QCLASS_INTERNET, receiptTimeMillis, cacheFlush,
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 4d79f9d8ea..1482ebb7a0 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
@@ -183,13 +183,10 @@ public class MdnsUtils {
}
/**
- * Create a raw DNS packet.
+ * Write the mdns packet from given MdnsPacket.
*/
- public static byte[] createRawDnsPacket(@NonNull byte[] packetCreationBuffer,
- @NonNull MdnsPacket packet) throws IOException {
- // TODO: support packets over size (send in multiple packets with TC bit set)
- final MdnsPacketWriter writer = new MdnsPacketWriter(packetCreationBuffer);
-
+ public static void writeMdnsPacket(@NonNull MdnsPacketWriter writer, @NonNull MdnsPacket packet)
+ throws IOException {
writer.writeUInt16(packet.transactionId); // Transaction ID (advertisement: 0)
writer.writeUInt16(packet.flags); // Response, authoritative (rfc6762 18.4)
writer.writeUInt16(packet.questions.size()); // questions count
@@ -210,6 +207,16 @@ public class MdnsUtils {
for (MdnsRecord record : packet.additionalRecords) {
record.write(writer, 0L);
}
+ }
+
+ /**
+ * Create a raw DNS packet.
+ */
+ public static byte[] createRawDnsPacket(@NonNull byte[] packetCreationBuffer,
+ @NonNull MdnsPacket packet) throws IOException {
+ // TODO: support packets over size (send in multiple packets with TC bit set)
+ final MdnsPacketWriter writer = new MdnsPacketWriter(packetCreationBuffer);
+ writeMdnsPacket(writer, packet);
final int len = writer.getWritePosition();
return Arrays.copyOfRange(packetCreationBuffer, 0, len);
--
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