Methods and systems for providing direct DMA

• US 9,154,453 B2
• Filed: 01/27/2012
• Issued: 10/06/2015
• Est. Priority Date: 01/16/2009
• Status: Active Grant

• Current Assignee: F5 Networks, Inc. (F5 Incorporated)
• Original Assignee: F5 Networks, Inc. (F5 Incorporated)
• Inventors: Michels, Timothy, Baumann, William R., Szabo, Paul I.
• Primary Examiner(s): Duong, Oanh
• Application Number:
  US13/360,340
• Publication Number:
  US 20120191800A1
• Time in Patent Office: 1,348 Days
• Field of Search: 709/212, 709/223, 709/250, 710/22, 710/308
• US Class Current: 1/1
• CPC Class Codes: H04L 49/901 using storage descriptor, e.g. read or write pointers

Abstract

A method and system for efficient direct DMA for processing connection state information or other expediting data packets. One example is the use of a network interface controller to buffer TCP type data packets that may contain connection state information. The connection state information is extracted from a received packet. The connection state information is stored in a special DMA descriptor that is stored in a ring buffer area of a buffer memory that is accessible by a host processor when an interrupt signal is received. The packet is then discarded. The host processor accesses the ring buffer memory only to retrieve the stored connection state information from the DMA descriptor without having to access a packet buffer area in the memory.

Claims

1. A method for efficiently processing a received data packet, the method comprising:

determining, by a network traffic management device, when a received data packet contains connection state information;

extracting, by the network traffic management device, the connection state information from the data packet when the data packet is determined to contain the connection state information;

storing, by the network traffic management device, the data packet in a non-contiguous packet buffer area and the connection state information extracted from the data packet as a special Direct Memory Access (DMA) descriptor in a contiguous ring buffer area configured to be capable of being accessible by a host processor, the stored connection state information comprising at least a state indicator; and

notifying, by the network traffic management device, the host processor that the special DMA descriptor has been stored, wherein the stored connection state information from the special DMA descriptor is configured to be capable of retrieval by the host processor.

2. The method of claim 1, wherein the data packet is a Transmission Control Protocol (TCP) data packet.

3. The method of claim 1, further comprising:

discarding, by the network traffic management device, the data packet after storing the connection state information.

4. The method of claim 1, further comprising:

writing, by the network traffic management device, the connection state information as the special DMA descriptor prior to storing the special DMA descriptor.

5. The method of claim 1, further comprising:

storing, by the network traffic management device, the data packet in a packet buffer area when the data packet is determined not to contain connection state information.

6. A non-transitory computer readable storage medium having stored thereon instructions for efficiently processing a received data packet comprising machine executable code which when executed by a processor, causes the processor to perform steps comprising:

determining when a received data packet contains connection state information;

extracting the connection state information from the data packet when the data packet is determined to contain the connection state information;

storing the data packet in a non-contiguous packet buffer area and the connection state information extracted from the data packet as a special Direct Memory Access (DMA) descriptor in a contiguous ring buffer area configured to be capable of being accessible by a host processor, the stored connection state information comprising at least a state indicator; and

notifying the host processor that the special DMA descriptor has been stored, wherein the stored connection state information from the special DMA descriptor is configured to be capable of retrieval by the host processor.

7. The medium of claim 6, wherein the data packet is a Transmission Control Protocol (TCP) data packet.

8. The medium of claim 6, further having stored thereon instructions that when executed by the processor cause the processor to performs steps further comprising:

discarding the data packet after storing the connection state information.

9. The medium of claim 6, further having stored thereon instructions that when executed by the processor cause the processor to performs steps further comprising:

writing the connection state information as the special DMA descriptor prior to storing the special DMA descriptor.

10. The medium of claim 6, further having stored thereon instructions that when executed by the processor cause the processor to performs steps further comprising

storing the data packet in a packet buffer area when the data packet is determined not to contain connection state information.

11. A network traffic management device comprising:

a processor;

a memory coupled to the processor and configured to be capable of executing programmed instructions comprising and stored in the memory to;

determine when a received data packet contains connection state information;

extract the connection state information from the data packet when the data packet is determined to contain the connection state information;

store the data packet in a non-contiguous packet buffer area and the connection state information extracted from the data packet as a special Direct Memory Access (DMA) descriptor in a contiguous ring buffer area configured to be capable of being accessible by a host processor, the stored connection state information comprising at least a state indicator; and

notify the host processor that the special DMA descriptor has been stored, wherein the stored connection state information from the special DMA descriptor is configured to be capable of retrieval by the host processor.

12. The network traffic management device of claim 11, wherein the data packet is a Transmission Control Protocol (TCP) data packet.

13. The network traffic management device of claim 11, wherein the processor is further configured to be capable of executing programmed instructions comprising and stored in the memory to:

discard the data packet after storing the connection state information.

14. The network traffic management device of claim 11, wherein the processor is further configured to be capable of executing programmed instructions comprising and stored in the memory to:

write the connection state information as the special DMA descriptor prior to storing the special DMA descriptor.

15. The network traffic management device of claim 11, wherein the processor is further configured to be capable of executing programmed instructions comprising and stored in the memory to:

store the data packet in a packet buffer area when the data packet is determined not to contain connection state information.