TCP/IP offload device with reduced sequential processing

• US 20060168281A1
• Filed: 02/06/2006
• Published: 07/27/2006
• Est. Priority Date: 12/05/2003
• Status: Abandoned Application

• Current Assignee: Alcritech, Inc.
• Original Assignee: Alacritech, Inc.
• Inventors: Philbrick, Clive M., Starr, Daryl D.
• Application Number:
  US11/348,810
• Publication Number:
  US 20060168281A1
• Time in Patent Office: Days
• US Class Current: 709/230
• CPC Class Codes: H04L 69/12 Protocol engines
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields

Abstract

A TCP Offload Engine (TOE) device includes a state machine that performs TCP/IP protocol processing operations in parallel. In a first aspect, the state machine includes a first memory, a second memory, and combinatorial logic. The first memory stores and simultaneously outputs multiple TCP state variables. The second memory stores and simultaneously outputs multiple header values. In contrast to a sequential processor technique, the combinatorial logic generates a flush detect signal from the TCP state variables and header values without performing sequential processor instructions or sequential memory accesses. In a second aspect, a TOE includes a state machine that performs an update of multiple TCP state variables in a TCB buffer all simultaneously, thereby avoiding multiple sequential writes to the TCB buffer memory. In a third aspect, a TOE involves a state machine that sets up a DMA move in a single state machine clock cycle.

Claims

1. A device comprising:

a parsing hardware unit that is configured to examine a received packet to determine a socket for the packet, the socket defined by source and destination Internet Protocol (IP) addresses and source and destination Transmission Control Protocol (TCP) ports for the packet;

a hashing hardware unit that is configured to generate, from the socket, a hash value for the packet; and

a socket detector hardware unit that uses the hash value to identify a group of TCP connections, and compares the socket with a plurality of sockets in the group of TCP connections, to identify a TCP connection from the group of TCP connections.

2. The device of claim 1, further comprising a signal to enable the socket detector hardware unit to identify the TCP connection, wherein the signal is on if the socket detector has received the socket from a processor, and the signal is off if the socket detector has not received the socket from the processor.

3. The device of claim 1, wherein the parsing hardware unit is configured to examine a second received packet, and determine that the transport layer protocol of the second packet is not TCP.

4. The device of claim 1, wherein the parsing hardware unit is configured to examine a second received packet, and determine that the network layer protocol of the second packet is not IP.

5. The device of claim 1, further comprising a memory unit that stores the hash value and does not store the packet.

6. The device of claim 5, wherein the memory unit is a queue.

7. The device of claim A, further comprising a processor running protocol processing instructions to establish the TCP connection.

8. A device comprising:

a processor running protocol processing instructions to establish Transmission Control Protocol (TCP) connection;

a parsing hardware unit that is configured to examine a received packet to determine a socket for the packet, the socket defined by source and destination Internet Protocol (IP) addresses and source and destination TCP ports for the packet;

a hashing hardware unit that is configured to generate, from the socket, a hash value for the packet; and

a socket detector hardware unit that uses the hash value to identify a group of TCP connections, and compares the socket with a plurality of sockets in the group of TCP connections, to identify a TCP connection from the group of TCP connections.

9. The device of claim 8, further comprising a signal to enable the socket detector hardware unit to identify the TCP connection, wherein the signal is on if the socket detector has received the socket from a processor, and the signal is off if the socket detector has not received the socket from the processor.

10. The device of claim 8, wherein the parsing hardware unit is configured to examine a second received packet, and determine that the transport layer protocol of the second packet is not TCP.

11. The device of claim 8, wherein the parsing hardware unit is configured to examine a second received packet, and determine that the network layer protocol of the second packet is not IP.

12. The device of claim 8, further comprising a memory unit that stores the hash value and does not store the packet.

13. The device of claim 12, wherein the memory unit is a queue.

14. A method comprising:

establishing a Transmission Control Protocol (TCP) connection that is identified by a pair of Internet Protocol (IP) addresses and a pair of TCP ports that define a socket, including running protocol processing instructions on a processor;

creating a hash number that is associated with the TCP connection and is based upon the socket;

storing the socket in a socket descriptor memory at an address which is specified by the hash number;

receiving a packet containing a header;

parsing the header of the packet with header parsing hardware to determine source and destination IP addresses and source and destination TCP ports for the packet;

hashing the IP addresses and the TCP ports with a hashing hardware unit to create a hash value for the packet; and

using the hash value to identify a group of sockets that are stored at the address; and

comparing, with a socket detector hardware unit, the source and destination IP addresses and TCP ports with the source and destination IP addresses and TCP ports of the sockets in the group, including identifying the TCP connection defined by the socket.

15. The method of claim 14, further comprising storing the hash value in a separate memory from the packet.

16. The method of claim 14, further comprising sending an identification of the socket from the processor to the socket detector hardware unit.

17. The method of claim 16, further comprising setting a detect enable indication after the socket detector has received the socket identification from the processor, prior to identifying the TCP connection from the group of TCP connections.

18. The method of claim 14, further comprising transferring control of the TCP connection from the processor to the socket detector hardware unit.

19. The method of claim 14, further comprising:

receiving a second packet; and

examining the second packet with the parsing hardware unit, including determining that the transport layer protocol of the second packet is not TCP.

20. The method of claim 14, further comprising:

receiving a second packet; and

examining the second packet with the parsing hardware unit, including determining that the network layer protocol of the second packet is not IP.