INT 7C - SK-UPPS Data Link Interface API(Application Program[ming] Interface) The defined set of calls which a program may make to interact with or request services of the operating system or environment under which it is running.  Because the inputs and outputs of the calls are well-defined, a program using the API can continue using the identical calls even if the internal organization of the program providing the API changes. - FEED BACK BUFFER
	AX = 000Fh
	ES:BX -> Mbuf (see #03847)
Return: nothing
Notes:	A protocol may call this function instead of returning the Mbuf
	  directly from the Receive Upcall if it is running in "promiscuous",
	  "hook" or "chain" mode.
SeeAlso: AX=0007h