Intel PCI-X Flexible Filter, IPX Diagnostic Responder Request Packet Example1, + D + S, Ipx

Power Management

6.4.3.3Flexible Filter

The Ethernet controller supports a total of four flexible filters. Each filter is configured to recognize any arbitrary pattern within the first 128 bytes of the packet. To configure the flexible filter, the software driver must mask values into the Flexible Filter Mask Table (FFMT), the required values into the Flexible Filter Value Table (FFVT), and the minimum packet length into the Flexible Filter Length Table (FFLT). These contain separate values for each filter. The software driver must also enable the filter in the Wakeup Filter Control Register (WUFC) as well as the overall wakeup functionality by setting PME_En in the Power Management Control Status Register or the Wakeup Control Register.

Once enabled, the flexible filters scan incoming packets for a match. If the filter encounters any byte in the packet where the mask bit is 1b and the byte doesn’t match the byte programmed in the Flexible Filter Value Table (FFVT), then the filter failed that packet. If the filter reaches the required length without failing the packet, it passes the packet and generates a wakeup event. It ignores any mask bits set to 1b beyond the required length. (the wakeup packet is stored, see Section 6.4.3.5).

For the 82541xx and 82547GI/EI, the flexible filter does not have any way to automatically skip VLAN or LLC/SNAP headers. If such headers are included, the offsets of the subsequent fields must be adjusted accordingly.

Note: This following flexible packet filters are listed for reference only.

6.4.3.3.1IPX Diagnostic Responder Request Packet Example1

	Offset	# of bytes	Field	Value	Action	Comment
0		6	Destination Address		Compare	MAC Header –
						processed by
6		6	Source Address		Skip	main address filter
12		S = (0/4)	Possible VLAN Tag		Compare or
					Skip
12	+ S	D = (0/8)	Possible LLC/SNAP Header		Compare or
					Skip
12	+ D + S	2	Type	8137h	Compare	IPX
14	+ D + S	16	Some IPX Stuff	-	Ignore
30	+ D + S	2	IPX Diagnostic Socket	0456h	Compare

1.82541xx and 82547GI/EI only.

Software Developer’s Manual 149