Index: dllmain.c
===================================================================
--- dll/win32/msafd/misc/dllmain.c	(revision 69828)
+++ dll/win32/msafd/misc/dllmain.c	(working copy)
@@ -2127,6 +2127,11 @@
                     break;
 
                 case SO_LINGER:
+                    if (Socket->SharedData.SocketType == SOCK_DGRAM)
+                    {
+                        *lpErrno = WSAENOPROTOOPT;
+                        return SOCKET_ERROR;
+                    }
                     Buffer = &Socket->SharedData.LingerData;
                     BufferSize = sizeof(struct linger);
                     break;
@@ -2202,7 +2207,8 @@
             return 0;
 
         default:
-            break;
+            *lpErrno = WSAEINVAL;
+            return SOCKET_ERROR;
     }
 
 SendToHelper:
@@ -2239,8 +2245,13 @@
 
 
     /* FIXME: We should handle some more cases here */
-    if (level == SOL_SOCKET)
+    if (level != SOL_SOCKET)
     {
+        *lpErrno = WSAEINVAL;
+        return SOCKET_ERROR;
+    }
+    else
+    {
         switch (optname)
         {
            case SO_BROADCAST: