Ignore floating interfaces

2 files changed, 58 insertions, 8 deletions

diff --git a/windows/windns/src/windns/dnsagent.cpp b/windows/windns/src/windns/dnsagent.cpp
index 6ff8ee9b39..13fca9613a 100644
--- a/windows/windns/src/windns/dnsagent.cpp
+++ b/windows/windns/src/windns/dnsagent.cpp
@@ -363,13 +363,29 @@ void DnsAgent::setNameServers(const std::wstring &interfaceGuid, const std::vect
 {
 	XTRACE(L"Overriding name servers for interface ", interfaceGuid);
 
+	uint32_t interfaceIndex = 0;
+
+	try
+	{
+		interfaceIndex = NetSh::ConvertInterfaceGuidToIndex(interfaceGuid);
+	}
+	catch (...)
+	{
+		//
+		// The interface cannot be linked to a virtual or physical adapter.
+		//
+
+		XTRACE(L"Ignoring floating interface ", interfaceGuid);
+		return;
+	}
+
 	if (Protocol::IPv4 == m_protocol)
 	{
-		NetSh::Instance().SetIpv4StaticDns(NetSh::ConvertInterfaceGuidToIndex(interfaceGuid), enforcedServers);
+		NetSh::Instance().SetIpv4StaticDns(interfaceIndex, enforcedServers);
 	}
 	else
 	{
-		NetSh::Instance().SetIpv6StaticDns(NetSh::ConvertInterfaceGuidToIndex(interfaceGuid), enforcedServers);
+		NetSh::Instance().SetIpv6StaticDns(interfaceIndex, enforcedServers);
 	}
 }
 
diff --git a/windows/windns/src/windns/recoverylogic.cpp b/windows/windns/src/windns/recoverylogic.cpp
index 0c630a89b2..6221c3c2b0 100644
--- a/windows/windns/src/windns/recoverylogic.cpp
+++ b/windows/windns/src/windns/recoverylogic.cpp
@@ -34,15 +34,32 @@ void RecoveryLogic::RestoreInterfaces(const RecoveryFormatter::Unpacked &data,
 				return;
 			}
 
-			XTRACE("Resetting name server configuration for interface ", snap.interfaceGuid());
+			XTRACE(L"Resetting name server configuration for interface ", snap.interfaceGuid());
+
+			uint32_t interfaceIndex = 0;
+
+			try
+			{
+				interfaceIndex = NetSh::ConvertInterfaceGuidToIndex(snap.interfaceGuid());
+			}
+			catch (...)
+			{
+				//
+				// The interface cannot be linked to a virtual or physical adapter.
+				// It's either floating or has been removed.
+				//
+
+				XTRACE(L"Ignoring floating/invalid interface ", snap.interfaceGuid());
+				return;
+			}
 
 			if (snap.nameServers().empty())
 			{
-				NetSh::Instance().SetIpv4DhcpDns(NetSh::ConvertInterfaceGuidToIndex(snap.interfaceGuid()), timeout);
+				NetSh::Instance().SetIpv4DhcpDns(interfaceIndex, timeout);
 			}
 			else
 			{
-				NetSh::Instance().SetIpv4StaticDns(NetSh::ConvertInterfaceGuidToIndex(snap.interfaceGuid()), snap.nameServers(), timeout);
+				NetSh::Instance().SetIpv4StaticDns(interfaceIndex, snap.nameServers(), timeout);
 			}
 		});
 
@@ -65,15 +82,32 @@ void RecoveryLogic::RestoreInterfaces(const RecoveryFormatter::Unpacked &data,
 				return;
 			}
 
-			XTRACE("Resetting name server configuration for interface ", snap.interfaceGuid());
+			XTRACE(L"Resetting name server configuration for interface ", snap.interfaceGuid());
+
+			uint32_t interfaceIndex = 0;
+
+			try
+			{
+				interfaceIndex = NetSh::ConvertInterfaceGuidToIndex(snap.interfaceGuid());
+			}
+			catch (...)
+			{
+				//
+				// The interface cannot be linked to a virtual or physical adapter.
+				// It's either floating or has been removed.
+				//
+
+				XTRACE(L"Ignoring floating/invalid interface ", snap.interfaceGuid());
+				return;
+			}
 
 			if (snap.nameServers().empty())
 			{
-				NetSh::Instance().SetIpv6DhcpDns(NetSh::ConvertInterfaceGuidToIndex(snap.interfaceGuid()), timeout);
+				NetSh::Instance().SetIpv6DhcpDns(interfaceIndex, timeout);
 			}
 			else
 			{
-				NetSh::Instance().SetIpv6StaticDns(NetSh::ConvertInterfaceGuidToIndex(snap.interfaceGuid()), snap.nameServers(), timeout);
+				NetSh::Instance().SetIpv6StaticDns(interfaceIndex, snap.nameServers(), timeout);
 			}
 		});