Now PCAP_IF_LOOPBACK flag in pcap_if_t struct will be set for "Npcap …

…Loopback Adapter" both for DLT_NULL mode and Fake Ethernet mode.

Common/Packet32.h

@@ -331,6 +331,7 @@ extern "C"
 	BOOLEAN PacketGetStatsEx(LPADAPTER AdapterObject, struct bpf_stat* s);
 	BOOLEAN PacketSetBuff(LPADAPTER AdapterObject, int dim);
 	BOOLEAN PacketGetNetType(LPADAPTER AdapterObject, NetType* type);
+	BOOLEAN PacketIsLoopbackAdapter(LPADAPTER AdapterObject);
 	LPADAPTER PacketOpenAdapter(PCHAR AdapterName);
 	BOOLEAN PacketSendPacket(LPADAPTER AdapterObject, LPPACKET pPacket, BOOLEAN Sync);
 	INT PacketSendPackets(LPADAPTER AdapterObject, PVOID PacketBuff, ULONG Size, BOOLEAN Sync);

packetWin7/Dll/AdInfo.c

@@ -74,9 +74,10 @@ static BOOLEAN PacketAddFakeNdisWanAdapter();
 static BOOLEAN IsIPv4Enabled(LPCSTR AdapterNameA);
 #endif
 
-PADAPTER_INFO g_AdaptersInfoList = NULL;	///< Head of the adapter information list. This list is populated when packet.dll is linked by the application.
-HANDLE g_AdaptersInfoMutex = NULL;			///< Mutex that protects the adapter information list. NOTE: every API that takes an ADAPTER_INFO as parameter assumes that it has been called with the mutex acquired.
-CHAR g_LoopbackAdapterName[100] = "";		///< The name of "Npcap Loopback Adapter", used for recording the NdisMediumNull link type for this adapter.
+#define BUFSIZE 512
+PADAPTER_INFO g_AdaptersInfoList = NULL;				///< Head of the adapter information list. This list is populated when packet.dll is linked by the application.
+HANDLE g_AdaptersInfoMutex = NULL;						///< Mutex that protects the adapter information list. NOTE: every API that takes an ADAPTER_INFO as parameter assumes that it has been called with the mutex acquired.
+CHAR g_LoopbackAdapterNameForDLTNull[BUFSIZE] = "";		///< The name of "Npcap Loopback Adapter", used for recording the NdisMediumNull link type for this adapter.
 
 extern FARPROC g_GetAdaptersAddressesPointer;
 
@@ -968,7 +969,7 @@ static BOOLEAN PacketAddAdapterIPH(PIP_ADAPTER_INFO IphAd)
 	}
 
 	// Set the NdisMediumNull value for "Npcap Loopback Adapter".
-	if (strcmp(g_LoopbackAdapterName, TmpAdInfo->Name) == 0)
+	if (strcmp(g_LoopbackAdapterNameForDLTNull, TmpAdInfo->Name) == 0)
 	{
 		TmpAdInfo->LinkLayer.LinkType = NdisMediumNull;
 	}
@@ -1173,7 +1174,7 @@ static BOOLEAN PacketAddAdapterNPF(PCHAR AdName, UINT flags)
 		// Record the name of "Npcap Loopback adapter", as we need it to set NdisMediumNull value for IPHelper version add adapter function.
 		if (TmpAdInfo->LinkLayer.LinkType == (UINT) NdisMediumNull)
 		{
-			strncpy(g_LoopbackAdapterName, TmpAdInfo->Name, sizeof(g_LoopbackAdapterName)/ sizeof(g_LoopbackAdapterName[0]) - 1);
+			strncpy(g_LoopbackAdapterNameForDLTNull, TmpAdInfo->Name, sizeof(g_LoopbackAdapterNameForDLTNull)/ sizeof(g_LoopbackAdapterNameForDLTNull[0]) - 1);
 		}
 
 		if (Status == FALSE)

packetWin7/Dll/Packet.def

@@ -21,6 +21,7 @@ EXPORTS
 		PacketGetStats
 		PacketGetStatsEx
 		PacketGetNetType
+		PacketIsLoopbackAdapter
 		PacketSetReadTimeout
 		PacketSetMode
 		PacketSetNumWrites

packetWin7/Dll/Packet32.c

@@ -68,6 +68,8 @@ BOOL g_IsRunByAdmin = FALSE;
 BOOL g_NPcapHelperTried = FALSE;
 // The handle to this DLL.
 HANDLE g_DllHandle = NULL;
+// The name of "Npcap Loopback Adapter".
+CHAR g_LoopbackAdapterName[BUFSIZE] = "";
 
 #ifdef _WINNT4
 #if (defined(HAVE_NPFIM_API) || defined(HAVE_WANPACKET_API) || defined (HAVE_AIRPCAP_API) || defined(HAVE_IPHELPER_API))
@@ -456,6 +458,32 @@ HANDLE NPcapRequestHandle(char *sMsg, DWORD *pdwError)
 	#define NPCAP_SOFTWARE_REGISTRY_KEY "SOFTWARE\\Wow6432Node\\" NPF_SOFT_REGISTRY_NAME
 #endif
 
+void NPcapGetLoopbackInterfaceName()
+{
+	HKEY hKey;
+	DWORD type;
+	char buffer[BUFSIZE];
+	int size = sizeof(buffer);
+
+#ifndef _X86_
+	Wow64EnableWow64FsRedirection(FALSE);
+#endif
+
+	if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, NPCAP_SOFTWARE_REGISTRY_KEY, 0, KEY_READ, &hKey) == ERROR_SUCCESS)
+	{
+		if (RegQueryValueExA(hKey, "Loopback", 0, &type,  (LPBYTE)buffer, &size) == ERROR_SUCCESS && type == REG_SZ)
+		{
+			strncpy(g_LoopbackAdapterName, buffer, sizeof(g_LoopbackAdapterName)/ sizeof(g_LoopbackAdapterName[0]) - 1);
+		}
+
+		RegCloseKey(hKey);
+	}
+
+#ifndef _X86_
+	Wow64EnableWow64FsRedirection(TRUE);
+#endif
+}
+
 BOOL NPcapIsAdminOnlyMode()
 {
 	HKEY hKey;
@@ -846,6 +874,9 @@ BOOL APIENTRY DllMain(HANDLE DllHandle,DWORD Reason,LPVOID lpReserved)
 		// XXX We want to replace this with a constant. We leave it out for the moment
 		// TODO fixme. Those hardcoded strings are terrible...
 		PacketGetFileVersion(TEXT("drivers\\") TEXT(NPF_DRIVER_NAME) TEXT(".sys"), PacketDriverVersion, sizeof(PacketDriverVersion));
+
+		// Get the name for "Npcap Loopback Adapter"
+		NPcapGetLoopbackInterfaceName();
 
 		break;
 
@@ -4595,6 +4626,32 @@ BOOLEAN PacketGetNetType(LPADAPTER AdapterObject, NetType *type)
 	return ret;
 }
 
+/*! 
+  \brief Returns whether an adapter is a loopback adapter (like Npcap loopback adapter).
+  \param AdapterObject The adapter on which information is needed.
+  \return TRUE if yes, FALSE if no.
+*/
+BOOLEAN PacketIsLoopbackAdapter(LPADAPTER AdapterObject)
+{
+	PADAPTER_INFO TAdInfo;
+	BOOLEAN ret;
+	TRACE_ENTER("PacketIsLoopbackAdapter");
+
+	// Set the return value to TRUE for "Npcap Loopback Adapter".
+	if (strcmp(g_LoopbackAdapterName + sizeof(DEVICE_PREFIX) - 1,
+		AdapterObject->Name + sizeof(DEVICE_PREFIX) - 1 + sizeof(NPF_DEVICE_NAMES_PREFIX) - 1) == 0)
+	{
+		ret = TRUE;
+	}
+	else
+	{
+		ret = FALSE;
+	}
+
+	TRACE_EXIT("PacketIsLoopbackAdapter");
+	return ret;
+}
+
 /*!
   \brief Returns the AirPcap handler associated with an adapter. This handler can be used to change
            the wireless-related settings of the CACE Technologies AirPcap wireless capture adapters.

wpcap/libpcap/inet.c

@@ -207,22 +207,10 @@ add_or_find_if(pcap_if_t **curdev_ret, pcap_if_t **alldevs, const char *name,
 			return (0);
 		}
 		else {
-			NetType type;
 			/*
 			 * Set PCAP_IF_LOOPBACK for "Npcap Loopback Adapter".
 			*/
-			if (PacketGetNetType(p->adapter, &type) == FALSE) {
-				(void)snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
-					"Cannot determine the network type: %s", pcap_win32strerror());
-			}
-			else {
-				if (type.LinkType == NdisMediumNull) {
-					npcap_loopback = 1;
-				}
-				else {
-					npcap_loopback = 0;
-				}
-			}
+			npcap_loopback = PacketIsLoopbackAdapter(p->adapter);
 		}
 		pcap_close(p);