api: use GetLastError() to report failures like standard Win32

Signed-off-by: Simon Rozman <simon@rozman.si>

1 files changed, 51 insertions, 36 deletions

diff --git a/example/example.c b/example/example.c
index cc3c32b..f6eec93 100644
--- a/example/example.c
+++ b/example/example.c
@@ -100,6 +100,15 @@ LogError(_In_z_ const WCHAR *Prefix, _In_ DWORD Error)
     return Error;

 }

 

+static DWORD

+LogLastError(_In_z_ const WCHAR *Prefix)

+{

+    DWORD LastError = GetLastError();

+    LogError(Prefix, LastError);

+    SetLastError(LastError);

+    return LastError;

+}

+

 static void

 Log(_In_ WINTUN_LOGGER_LEVEL Level, _In_z_ const WCHAR *Format, ...)

 {

@@ -206,22 +215,26 @@ ReceivePackets(_Inout_ DWORD_PTR SessionPtr)
 

     while (!HaveQuit)

     {

-        BYTE *Packet;

         DWORD PacketSize;

-        DWORD Result = WintunReceivePacket(Session, &Packet, &PacketSize);

-        switch (Result)

+        BYTE *Packet = WintunReceivePacket(Session, &PacketSize);

+        if (Packet)

         {

-        case ERROR_SUCCESS:

             PrintPacket(Packet, PacketSize);

             WintunReceiveRelease(Session, Packet);

-            continue;

-        case ERROR_NO_MORE_ITEMS:

-            if (WaitForMultipleObjects(_countof(WaitHandles), WaitHandles, FALSE, INFINITE) == WAIT_OBJECT_0)

-                continue;

-            return ERROR_SUCCESS;

-        default:

-            LogError(L"Packet read failed", Result);

-            return Result;

+        }

+        else

+        {

+            DWORD LastError = GetLastError();

+            switch (LastError)

+            {

+            case ERROR_NO_MORE_ITEMS:

+                if (WaitForMultipleObjects(_countof(WaitHandles), WaitHandles, FALSE, INFINITE) == WAIT_OBJECT_0)

+                    continue;

+                return ERROR_SUCCESS;

+            default:

+                LogError(L"Packet read failed", LastError);

+                return LastError;

+            }

         }

     }

     return ERROR_SUCCESS;

@@ -233,8 +246,9 @@ SendPackets(_Inout_ DWORD_PTR SessionPtr)
     WINTUN_SESSION_HANDLE Session = (WINTUN_SESSION_HANDLE)SessionPtr;

     while (!HaveQuit)

     {

-        BYTE *Packet;

-        WintunAllocateSendPacket(Session, 28, &Packet);

+        BYTE *Packet = WintunAllocateSendPacket(Session, 28);

+        if (!Packet)

+            return LogLastError(L"Packet write failed");

         MakeICMP(Packet);

         WintunSendPacket(Session, Packet);

 

@@ -269,9 +283,9 @@ InitializeWintun(void)
         X(WintunAllocateSendPacket, WINTUN_ALLOCATE_SEND_PACKET_FUNC) || X(WintunSendPacket, WINTUN_SEND_PACKET_FUNC))

 #undef X

     {

-        DWORD Result = GetLastError();

+        DWORD LastError = GetLastError();

         FreeLibrary(Wintun);

-        SetLastError(Result);

+        SetLastError(LastError);

         return NULL;

     }

     SetLastError(ERROR_SUCCESS);

@@ -287,29 +301,31 @@ main(void)
     WintunSetLogger(ConsoleLogger);

     Log(WINTUN_LOG_INFO, L"Wintun library loaded");

 

-    DWORD Result;

+    DWORD LastError;

     HaveQuit = FALSE;

     QuitEvent = CreateEventW(NULL, TRUE, FALSE, NULL);

     if (!QuitEvent)

     {

-        Result = LogError(L"Failed to create event", GetLastError());

+        LastError = LogError(L"Failed to create event", GetLastError());

         goto cleanupWintun;

     }

     if (!SetConsoleCtrlHandler(CtrlHandler, TRUE))

     {

-        Result = LogError(L"Failed to set console handler", GetLastError());

+        LastError = LogError(L"Failed to set console handler", GetLastError());

         goto cleanupQuit;

     }

 

     GUID ExampleGuid = { 0xdeadbabe, 0xcafe, 0xbeef, { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef } };

-    WINTUN_ADAPTER_HANDLE Adapter;

-    Result = WintunGetAdapter(L"Example", L"Demo", &Adapter);

-    if (Result != ERROR_SUCCESS)

-        Result = WintunCreateAdapter(L"Example", L"Demo", &ExampleGuid, &Adapter, NULL);

-    if (Result != ERROR_SUCCESS)

+    WINTUN_ADAPTER_HANDLE Adapter = WintunGetAdapter(L"Example", L"Demo");

+    if (!Adapter)

     {

-        LogError(L"Failed to create adapter", Result);

-        goto cleanupQuit;

+        Adapter = WintunCreateAdapter(L"Example", L"Demo", &ExampleGuid, NULL);

+        if (!Adapter)

+        {

+            LastError = GetLastError();

+            LogError(L"Failed to create adapter", LastError);

+            goto cleanupQuit;

+        }

     }

 

     DWORD Version = WintunGetVersion();

@@ -321,18 +337,17 @@ main(void)
     AddressRow.Address.Ipv4.sin_family = AF_INET;

     AddressRow.Address.Ipv4.sin_addr.S_un.S_addr = htonl((10 << 24) | (6 << 16) | (7 << 8) | (7 << 0)); /* 10.6.7.7 */

     AddressRow.OnLinkPrefixLength = 24; /* This is a /24 network */

-    Result = CreateUnicastIpAddressEntry(&AddressRow);

-    if (Result != ERROR_SUCCESS && Result != ERROR_OBJECT_ALREADY_EXISTS)

+    LastError = CreateUnicastIpAddressEntry(&AddressRow);

+    if (LastError != ERROR_SUCCESS && LastError != ERROR_OBJECT_ALREADY_EXISTS)

     {

-        LogError(L"Failed to set IP address", Result);

+        LogError(L"Failed to set IP address", LastError);

         goto cleanupAdapter;

     }

 

-    WINTUN_SESSION_HANDLE Session;

-    Result = WintunStartSession(Adapter, 0x40000, &Session);

-    if (Result != ERROR_SUCCESS)

+    WINTUN_SESSION_HANDLE Session = WintunStartSession(Adapter, 0x40000);

+    if (!Session)

     {

-        LogError(L"Failed to create adapter", Result);

+        LastError = LogLastError(L"Failed to create adapter");

         goto cleanupAdapter;

     }

 

@@ -342,11 +357,11 @@ main(void)
                          CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)SendPackets, (LPVOID)Session, 0, NULL) };

     if (!Workers[0] || !Workers[1])

     {

-        Result = LogError(L"Failed to create threads", GetLastError());

+        LastError = LogError(L"Failed to create threads", GetLastError());

         goto cleanupWorkers;

     }

     WaitForMultipleObjectsEx(_countof(Workers), Workers, TRUE, INFINITE, TRUE);

-    Result = ERROR_SUCCESS;

+    LastError = ERROR_SUCCESS;

 

 cleanupWorkers:

     HaveQuit = TRUE;

@@ -368,5 +383,5 @@ cleanupQuit:
     CloseHandle(QuitEvent);

 cleanupWintun:

     FreeLibrary(Wintun);

-    return Result;

+    return LastError;

 }