System and method for parsing, filtering, and computing the checksum in a host Ethernet adapter (HEA)

• US 7,706,409 B2
• Filed: 04/01/2005
• Issued: 04/27/2010
• Est. Priority Date: 04/01/2005
• Status: Active Grant

• Current Assignee: X Corp. (f/k/a Twitter, Inc.) (X Holdings Corp.)
• Original Assignee: International Business Machines Corporation
• Inventors: Damon, Philippe, Vaidhyanathan, Natarajan, Calvignac, Jean Louis, Verplanken, Fabrice Jean, Basso, Claude, Verrilli, Colin Beaton, Chang, Chih-Jen
• Primary Examiner(s): Mattis; Jason E
• Assistant Examiner(s): Chery; Dady
• Application Number:
  US11/096,365
• Publication Number:
  US 20060221952A1
• Time in Patent Office: 1,852 Days
• Field of Search: 370/389, 370/392, 370/471, 370/401, 370/429, 370/470, 370/474, 370/476, 714/746, 714/758, 714/799, 714/807, 709/230, 709/236
• US Class Current: 370/474
• CPC Class Codes: H04L 1/0052 Realisations of complexity reduction techniques, e.g. pipelining or use of look-up tables
• CPC Class Codes: H04L 1/0061 Error detection codes

Abstract

A system and method for parsing, filtering, and computing the checksum in a host Ethernet adapter (HEA) that is coupled to a host. The method includes receiving a part of a frame, wherein a plurality of parts of a frame constitute a entire frame. Next, parse the part of a frame before receiving the entire frame. The HEA computes a checksum of the part of a frame. The HEA filters the part of a frame based on a logical, port-specific policy and transmits the checksum to the host.

Claims

1. A method for parsing, filtering, and computing a checksum using a host Ethernet adapter (HEA) coupled to a host computer, the method comprising:

receiving a part of a frame with the HEA, wherein a plurality of parts of the frame constitute an entire frame;

parsing the part of the frame with the HEA before receiving the entire frame;

computing a checksum of the part of the frame with the HEA before receiving the entire frame;

filtering, with the HEA, the part of the frame based on a logical, port-specific policy before receiving the entire frame,

wherein a plurality of parts of the frame are received to constitute the frame, and wherein at a time when a last part of the frame is received, the parsing, filtering, and computing the checksum is performed on the last part of the frame with no additional parsing, filtering, and computing the checksum needed for the frame;

transmitting the checksum with the HEA to the host computer; and

during reception of one or more initial parts of the plurality of parts of the frame with the HEA, performing pre-filtering processing with the HEA including loading the logical, port specific filter policy into one or more registers of the HEA for use with the filtering.

2. The method of claim 1, wherein the parsing step comprises:

keeping track of the part of the frame that is received; and

determining if the frame is in a particular format, wherein the format can be any of a multicast, broadcast or unicast format.

3. The method of claim 1, wherein the pre-filtering processing is performed such that the HEA is ready to filter the part of the frame using the logical, port specific policy after a number of clock cycles of the HEA in accordance with a soonest time specified by a standard used by the HEA in receiving the parts of the frame.

4. The method of claim 3, wherein the pre-filtering processing includes:

reading a plurality of filter policies and loading the plurality of filter policies into registers of the HEA, the plurality of filter policies including a MAC filter policy, a Virtual Local Area Network (VLAN) filter policy, and the logical port specific policy, such that the HEA is ready to filter the part of the frame using the plurality of filter policies after the number of clock cycles of the HEA in accordance with the soonest time specified by the standard used by the HEA in receiving the parts of the frame; and

determining a logical port destination of the frame.

5. The method of claim 1, wherein the parsing step detects a protocol payload by examining a protocol field in a header of the frame.

6. The method of claim 1, which includes forwarding results to the filtering step.

7. The method of claim 1, wherein a minimum number of portions of the frame are required to be received before the filtering of the part of the frame is performed, and wherein the pre-filtering processing is started during the reception of the initial parts of the frame and is performed and completed by the time the minimum number of portions of the frame are received.

8. The method of claim 1, wherein the filtering includes Virtual Local Area Network (VLAN) filtering.

9. The method of claim 1, wherein the filtering includes applying a different filter for each of a plurality of different logical partitions provided in a single memory storage area in a server system, wherein each of the logical partitions has different criteria to determine whether a frame is sent to that logical partition.

10. The method of claim 1 further comprising detecting whether the frame is an IP fragment indicating that the frame was broken up during transmission and a particular protocol header is not present in the frame.

11. The method of claim 1 wherein the parsing includes parsing a particular field in a header in the frame using a byte-offset stake that indicates a location of the particular field in the frame, wherein a first portion of the bits of the stake are used to indicate a particular one of the parts of the frame numbered from the beginning of the frame, and a second portion of the bits of the stake determines a byte offset within the particular part of the frame.

12. A host Ethernet adapter (HEA) coupled to a host computer, the HEA for parsing, filtering, and computing a checksum, the system comprising:

a mechanism for receiving a part of a frame, wherein a plurality of parts of the frame constitute an entire frame;

a parser for parsing the part of the frame before receiving the entire frame;

a mechanism for computing a checksum of the part of the frame before receiving the entire frame;

a mechanism for filtering the part of the frame based on a logical, port-specific policy before receiving the entire frame,

wherein a plurality of parts of the frame are received to constitute the frame, and wherein at a time when a last part of the frame is received, the parser, the mechanism for filtering, and the mechanism for computing the checksum perform parsing, filtering, and computing the checksum, respectively, on the last part of the frame with no additional parsing, filtering, and computing the checksum needed for the frame;

a mechanism for transmitting the checksum to the host computer; and

a mechanism for performing pre-filtering processing during reception of one or more initial parts of the plurality of parts of the frame, the pre-filtering processing including loading the logical, port specific filter policy into one or more registers of the HEA for use with the filtering.

13. The host Ethernet adapter of claim 12, wherein the pre-filtering processing is performed such that the mechanism for filtering is ready to filter the part of the frame using the logical, port specific policy after a number of clock cycles of the HEA in accordance with a soonest time specified by a standard used by the HEA in receiving the parts of the frame.

14. The host Ethernet adapter of claim 12, wherein the parser keeps track of the part of the frame that is received and determines if the frame is in a particular format.

15. The host Ethernet adapter of claim 14, wherein the format can be any of a multicast, broadcast or unicast format.

16. The host Ethernet adapter of claim 12, wherein a minimum number of portions of the frame are required to be received before the mechanism for filtering filters the part of the frame, and wherein the filtering initialization is started during the reception of the initial parts of the frame and is performed and completed by the time the minimum number of portions of the frame are received.

17. The host Ethernet adapter of claim 12, wherein the mechanism for performing pre-filtering processing reads a plurality of filter policies and loads the plurality of filter policies into registers of the HEA, the plurality of filter policies including a MAC filter policy, a Virtual Local Area Network (VLAN) filter policy, and the logical port specific policy, and wherein the mechanism for performing pre-filtering processing determines a logical port destination of the frame.

18. The host Ethernet adapter of claim 12, wherein the mechanism for filtering applies a different filter for each of a plurality of different logical partitions provided in a single memory storage area in a server system, wherein each of the logical partitions has different criteria to determine whether a frame is sent to that logical partition.

19. The host Ethernet adapter of claim 12 further comprising a mechanism for detecting whether the frame is an IP fragment indicating that the frame was broken up during transmission and a particular protocol header is not present in the frame.

20. The host Ethernet adapter of claim 12 wherein the parser parses a particular field in a header in the frame using a byte-offset stake that indicates a location of the particular field in the frame, wherein a first portion of the bits of the stake are used to indicate a particular one of the parts of the frame numbered from the beginning of the frame, and a second portion of the bits of the stake determines a byte offset within the particular part of the frame.