Filter out most irrelevant interface events

2 files changed, 54 insertions, 7 deletions

diff --git a/windows/winnet/src/winnet/routing/defaultroutemonitor.cpp b/windows/winnet/src/winnet/routing/defaultroutemonitor.cpp
index 56521ec9d8..cd0f7304e2 100644
--- a/windows/winnet/src/winnet/routing/defaultroutemonitor.cpp
+++ b/windows/winnet/src/winnet/routing/defaultroutemonitor.cpp
@@ -23,6 +23,7 @@ DefaultRouteMonitor::DefaultRouteMonitor
 	: m_family(family)
 	, m_callback(callback)
 	, m_logSink(logSink)
+	, m_refreshCurrentRoute(false)
 	, m_evaluateRoutesGuard(std::make_unique<common::BurstGuard>(
 		std::bind(&DefaultRouteMonitor::evaluateRoutes, this),
 		POINT_TWO_SECOND_BURST,
@@ -102,29 +103,62 @@ void NETIOAPI_API_ DefaultRouteMonitor::RouteChangeCallback
 		return;
 	}
 
-	reinterpret_cast<DefaultRouteMonitor *>(context)->m_evaluateRoutesGuard->trigger();
+	const auto monitor = reinterpret_cast<DefaultRouteMonitor*>(context);
+	monitor->updateRefreshFlag(row->InterfaceLuid, row->InterfaceIndex);
+	monitor->m_evaluateRoutesGuard->trigger();
 }
 
 //static
 void NETIOAPI_API_ DefaultRouteMonitor::InterfaceChangeCallback
 (
 	void *context,
-	MIB_IPINTERFACE_ROW *,
+	MIB_IPINTERFACE_ROW *row,
 	MIB_NOTIFICATION_TYPE
 )
 {
-	reinterpret_cast<DefaultRouteMonitor *>(context)->m_evaluateRoutesGuard->trigger();
+	const auto monitor = reinterpret_cast<DefaultRouteMonitor*>(context);
+	monitor->updateRefreshFlag(row->InterfaceLuid, row->InterfaceIndex);
+	monitor->m_evaluateRoutesGuard->trigger();
 }
 
 //static
 void NETIOAPI_API_ DefaultRouteMonitor::AddressChangeCallback
 (
-	void* context,
-	MIB_UNICASTIPADDRESS_ROW*,
+	void *context,
+	MIB_UNICASTIPADDRESS_ROW *row,
 	MIB_NOTIFICATION_TYPE
 )
 {
-	reinterpret_cast<DefaultRouteMonitor*>(context)->m_evaluateRoutesGuard->trigger();
+	const auto monitor = reinterpret_cast<DefaultRouteMonitor*>(context);
+	monitor->updateRefreshFlag(row->InterfaceLuid, row->InterfaceIndex);
+	monitor->m_evaluateRoutesGuard->trigger();
+}
+
+void DefaultRouteMonitor::updateRefreshFlag(const NET_LUID &luid, const NET_IFINDEX &index)
+{
+	std::scoped_lock<std::mutex> lock(m_evaluationLock);
+
+	if (!m_bestRoute.has_value())
+	{
+		return;
+	}
+
+	if (luid.Value == m_bestRoute->iface.Value)
+	{
+		m_refreshCurrentRoute = true;
+		return;
+	}
+
+	if (luid.Value != 0)
+	{
+		return;
+	}
+
+	NET_IFINDEX defaultInterfaceIndex = 0;
+	const auto routeLuid = &m_bestRoute->iface;
+	ConvertInterfaceLuidToIndex(routeLuid, &defaultInterfaceIndex);
+	m_refreshCurrentRoute = index == defaultInterfaceIndex ||
+		(defaultInterfaceIndex == NET_IFINDEX_UNSPECIFIED);
 }
 
 void DefaultRouteMonitor::evaluateRoutes()
@@ -150,6 +184,9 @@ void DefaultRouteMonitor::evaluateRoutesInner()
 {
 	std::optional<InterfaceAndGateway> currentBestRoute;
 
+	bool refreshCurrent = m_refreshCurrentRoute;
+	m_refreshCurrentRoute = false;
+
 	try
 	{
 		currentBestRoute = GetBestDefaultRoute(m_family);
@@ -194,8 +231,15 @@ void DefaultRouteMonitor::evaluateRoutesInner()
 	{
 		m_bestRoute = currentBestRoute;
 		m_callback(EventType::Updated, m_bestRoute);
+
+		return;
 	}
-	else
+
+	//
+	// Interface details may have changed.
+	//
+
+	if (refreshCurrent)
 	{
 		m_callback(EventType::UpdatedDetails, m_bestRoute);
 	}
diff --git a/windows/winnet/src/winnet/routing/defaultroutemonitor.h b/windows/winnet/src/winnet/routing/defaultroutemonitor.h
index 24be69a835..ce2a3ce3f6 100644
--- a/windows/winnet/src/winnet/routing/defaultroutemonitor.h
+++ b/windows/winnet/src/winnet/routing/defaultroutemonitor.h
@@ -57,6 +57,7 @@ private:
 	std::unique_ptr<common::BurstGuard> m_evaluateRoutesGuard;
 
 	std::optional<InterfaceAndGateway> m_bestRoute;
+	bool m_refreshCurrentRoute;
 
 	HANDLE m_routeNotificationHandle;
 	HANDLE m_interfaceNotificationHandle;
@@ -68,6 +69,8 @@ private:
 	static void NETIOAPI_API_ InterfaceChangeCallback(void *context, MIB_IPINTERFACE_ROW *row, MIB_NOTIFICATION_TYPE notificationType);
 	static void NETIOAPI_API_ AddressChangeCallback(void *context, MIB_UNICASTIPADDRESS_ROW *row, MIB_NOTIFICATION_TYPE notificationType);
 
+	void updateRefreshFlag(const NET_LUID &luid, const NET_IFINDEX &index);
+
 	void evaluateRoutes();
 	void evaluateRoutesInner();
 };