Fix concurrent mDNS resolution by verifying requested hostname

CHANGELOG.md

@@ -44,6 +44,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   - LED-device updates queue up and let Hyperion crash (#1887)
   - The color of the backlight threshold is green, not white/gray (#1899)
   - Install - Ubuntu 25.10 unable to install due to libcec package (#1934)
+  - Fix concurrent mDNS resolution (#1906)
 
 ---
 
@@ -61,7 +62,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **Fixes:**
   - WebUI unreachable via IPv6 (#1871)
   - Align install_pr script working with default Qt6 builds & show authentication failures (#1871)
-  
+
 - **Build:**
     - Added Debian Trixie to PR-builds for early testing
 

include/mdns/MdnsBrowser.h

@@ -17,6 +17,7 @@
 #include <QByteArray>
 #include <QMap>
 #include <QJsonArray>
+#include <QString>
 #include <QSharedPointer>
 #include <QScopedPointer>
 
@@ -88,10 +89,9 @@ public slots:
 	 */
 	void serviceRemoved(const QMdnsEngine::Service& service);
 
-	void isAddressResolved(QHostAddress address);
-	void isFirstAddressResolved(QHostAddress address);
+	void isFirstAddressResolved(QString hostname, QHostAddress address);
 
-	void isServiceRecordResolved(QMdnsEngine::Record serviceRecord) const;
+	void isServiceRecordResolved(QByteArray serviceInstance, QMdnsEngine::Record serviceRecord) const;
 
 private slots:
 
@@ -101,8 +101,6 @@ private slots:
 	void onServiceUpdated(const QMdnsEngine::Service& service);
 	void onServiceRemoved(const QMdnsEngine::Service& service);
 
-	void onHostNameResolved(const QHostAddress& address);
-
 private:
 	/// The logger instance for mDNS-Service
 	QSharedPointer<Logger> _log;

include/utils/NetUtils.h

@@ -118,8 +118,15 @@ inline bool resolveMDnsHostToAddress(QSharedPointer<Logger> log, const QString&
 			QEventLoop loop;
 
 			// Connect the signal to capture the resolved address
-			QObject::connect(browser, &MdnsBrowser::isFirstAddressResolved, &loop, [&](QHostAddress addr) {
-				hostAddress = std::move(addr);
+			QString const requestedHostname = hostname;
+			QObject::connect(browser, &MdnsBrowser::isFirstAddressResolved, &loop,
+							 [&, requestedHostname](const QString& resolvedHostname, const QHostAddress& addr) {
+				if (resolvedHostname.compare(requestedHostname, Qt::CaseInsensitive) != 0)
+				{
+					return;
+				}
+
+				hostAddress = addr;
 				loop.quit();
 			});
 
@@ -189,7 +196,14 @@ inline QMdnsEngine::Record resolveMDnsServiceRecord(const QByteArray& serviceIns
 		QEventLoop loop;
 
 		// Connect the signal to capture the resolved service record
-		QObject::connect(browser, &MdnsBrowser::isServiceRecordResolved, &loop, [&](QMdnsEngine::Record resolvedServiceRecord) {
+		QByteArray const requestedService = serviceInstance;
+		QObject::connect(browser, &MdnsBrowser::isServiceRecordResolved, &loop,
+						 [&, requestedService](const QByteArray& emittedService, const QMdnsEngine::Record& resolvedServiceRecord) {
+			if (emittedService != requestedService)
+			{
+				return;
+			}
+
 			serviceRecord = resolvedServiceRecord;
 			loop.quit();
 		});
@@ -224,27 +238,29 @@ inline bool resolveHostToAddress(QSharedPointer<Logger> log, const QString& host
 	if (hostname.endsWith("._tcp.local"))
 	{
 		//Treat hostname as service instance name that requires to be resolved into an mDNS-Hostname first
-		QMdnsEngine::Record const service = resolveMDnsServiceRecord(hostname.toUtf8());
-		if (!service.target().isEmpty())
+		QByteArray requestedService = hostname.toUtf8();
+		if (!requestedService.endsWith('.'))
 		{
-			if (!service.target().isEmpty())
-			{
-				Info(log, "Resolved service [%s] to mDNS hostname [%s], service port [%d]", QSTRING_CSTR(hostname), service.target().constData(), service.port());
-				target = service.target();
-				port = service.port();
-			}
-			else
-			{
-				Error(log, "Failed to resolved service [%s] to an mDNS hostname", QSTRING_CSTR(hostname));
-				return false;
-			}
+			requestedService.append('.');
 		}
-		else
+
+		QMdnsEngine::Record const serviceRecord = resolveMDnsServiceRecord(hostname.toUtf8());
+		if (serviceRecord.name().isEmpty() || serviceRecord.target().isEmpty())
 		{
 			Error(log, "Cannot resolve mDNS hostname for given service [%s]!", QSTRING_CSTR(hostname));
 			return false;
 		}
 
+		if (serviceRecord.name() != requestedService)
+		{
+			Error(log, "Resolved record [%s] does not match requested service [%s]", serviceRecord.name().constData(), requestedService.constData());
+			return false;
+		}
+
+		Info(log, "Resolved service [%s] to mDNS hostname [%s], service port [%d]", QSTRING_CSTR(hostname), serviceRecord.target().constData(), serviceRecord.port());
+		target = serviceRecord.target();
+		port = serviceRecord.port();
+
 		QHostAddress resolvedAddress;
 		if (NetUtils::resolveMDnsHostToAddress(log, target, resolvedAddress))
 		{
@@ -286,27 +302,29 @@ inline bool resolveMdnsHost(QSharedPointer<Logger> log, QString& hostname, int&
 	if (hostname.endsWith("._tcp.local"))
 	{
 		//Treat hostname as service instance name that requires to be resolved into an mDNS-Hostname first
-		QMdnsEngine::Record const service = resolveMDnsServiceRecord(hostname.toUtf8());
-		if (!service.target().isEmpty())
+		QByteArray requestedService = hostname.toUtf8();
+		if (!requestedService.endsWith('.'))
 		{
-			if (!service.target().isEmpty())
-			{
-				Info(log, "Resolved service [%s] to mDNS hostname [%s], service port [%d]", QSTRING_CSTR(hostname), service.target().constData(), service.port());
-				target = service.target();
-				port = service.port();
-			}
-			else
-			{
-				Error(log, "Failed to resolved service [%s] to an mDNS hostname", QSTRING_CSTR(hostname));
-				return false;
-			}
+			requestedService.append('.');
 		}
-		else
+
+		QMdnsEngine::Record const serviceRecord = resolveMDnsServiceRecord(hostname.toUtf8());
+		if (serviceRecord.name().isEmpty() || serviceRecord.target().isEmpty())
 		{
 			Error(log, "Cannot resolve mDNS hostname for given service [%s]!", QSTRING_CSTR(hostname));
 			return false;
 		}
 
+		if (serviceRecord.name() != requestedService)
+		{
+			Error(log, "Resolved record [%s] does not match requested service [%s]", serviceRecord.name().constData(), requestedService.constData());
+			return false;
+		}
+
+		Info(log, "Resolved service [%s] to mDNS hostname [%s], service port [%d]", QSTRING_CSTR(hostname), serviceRecord.target().constData(), serviceRecord.port());
+		target = serviceRecord.target();
+		port = serviceRecord.port();
+
 		QHostAddress resolvedAddress;
 		if (NetUtils::resolveMDnsHostToAddress(log, target, resolvedAddress))
 		{

libsrc/mdns/MdnsBrowser.cpp

@@ -116,21 +116,6 @@ void MdnsBrowser::onServiceRemoved(const QMdnsEngine::Service& service)
 	emit serviceRemoved(service);
 }
 
-void MdnsBrowser::onHostNameResolved(const QHostAddress& address)
-{
-	DebugIf(verboseBrowser, _log, "for address [%s], Thread: %s", QSTRING_CSTR(address.toString()), QSTRING_CSTR(QThread::currentThread()->objectName()));
-
-	// Do not publish link local addresses
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 11, 0))
-	if (!address.isLinkLocal())
-#else
-	if (!address.toString().startsWith("fe80"))
-#endif
-	{
-		emit isAddressResolved(address);
-	}
-}
-
 void MdnsBrowser::resolveFirstAddress(QSharedPointer<Logger> log, const QString& hostname, std::chrono::milliseconds timeout)
 {
 	qRegisterMetaType<QMdnsEngine::Message>("Message");
@@ -140,24 +125,28 @@ void MdnsBrowser::resolveFirstAddress(QSharedPointer<Logger> log, const QString&
 	if (hostname.endsWith(".local") || hostname.endsWith(".local."))
 	{
 		QMdnsEngine::Resolver const resolver (_server.get(), hostname.toUtf8(), _cache.get());
-		connect(&resolver, &QMdnsEngine::Resolver::resolved, this, &MdnsBrowser::onHostNameResolved);
 
 		DebugIf(verboseBrowser, log, "Wait for resolver on hostname [%s]", QSTRING_CSTR(hostname));
 
 		QEventLoop loop;
 		QTimer timer;
 
 		timer.setSingleShot(true);
-		connect(&timer, &QTimer::timeout, this, [&loop]() {
-			loop.quit();  // Stop waiting if timeout occurs
-		});
+		connect(&timer, &QTimer::timeout, &loop, &QEventLoop::quit);
+
+		connect(&resolver, &QMdnsEngine::Resolver::resolved, &loop, [ &loop, &resolvedAddress ](const QHostAddress& address) {
+			// Ignore link-local addresses
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 11, 0))
+			if (address.isLinkLocal())
+#else
+			if (address.toString().startsWith("fe80"))
+#endif
+			{
+				return;
+			}
 
-		std::unique_ptr<QObject> context{new QObject};
-		QObject* pcontext = context.get();
-		connect(this, &MdnsBrowser::isAddressResolved, pcontext, [ &loop, &resolvedAddress, context = std::move(context)](const QHostAddress &address) mutable {
 			resolvedAddress = address;
 			loop.quit();
-			context.reset();
 		});
 
 		timer.start(timeout);
@@ -177,7 +166,7 @@ void MdnsBrowser::resolveFirstAddress(QSharedPointer<Logger> log, const QString&
 		Error(log, "Hostname [%s] is not an mDNS hostname.", QSTRING_CSTR(hostname));
 	}
 
-	emit isFirstAddressResolved(resolvedAddress);
+	emit isFirstAddressResolved(hostname, resolvedAddress);
 }
 
 void MdnsBrowser::resolveServiceInstance(const QByteArray& serviceInstance, const std::chrono::milliseconds waitTime) const
@@ -225,7 +214,7 @@ void MdnsBrowser::resolveServiceInstance(const QByteArray& serviceInstance, cons
 			Debug(_log, "No service record found for service instance [%s]", service.constData());
 		}
 	}
-	emit isServiceRecordResolved(srvRecord);
+	emit isServiceRecordResolved(serviceInstance, srvRecord);
 }
 
 QMdnsEngine::Service MdnsBrowser::getFirstService(const QByteArray& serviceType, const QString& filter, const std::chrono::milliseconds waitTime) const