Method to synchronize and upload an offloaded network stack connection with a network stack

• US 7,181,531 B2
• Filed: 04/30/2002
• Issued: 02/20/2007
• Est. Priority Date: 04/30/2002
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Pinkerton, James T., Gbadegesin, Abolade, Kaniyar, Sanjay, Srinivas, Nelamangala Krishaswamy
• Primary Examiner(s): Dharia; Rupal
• Assistant Examiner(s): Patel; Chirag R.
• Application Number:
  US10/135,630
• Publication Number:
  US 20030204631A1
• Time in Patent Office: 1,757 Days
• Field of Search: 709/230, 709/250, 709/238, 710/15
• US Class Current: 709/238
• CPC Class Codes: H04L 69/10 Streamlined, light-weight or high-speed protocols, e.g. express transfer protocol [XTP] or byte stream
• 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
• CPC Class Codes: H04L 69/166 IP fragmentation; TCP segmentation
• CPC Class Codes: H04L 69/32 Architecture of open systems interconnection [OSI] 7-layer type protocol stacks, e.g. the interfaces between the data link level and the physical level

Abstract

A method to synchronize and upload an offloaded network stack connection between a host network stack and peripheral device is presented. A state object for each layer in the stack is sent to the device that includes state variables that are classified as a constant, a cached variable handled by the host, or a delegated variable handled by the device. State that must be updated by the network stack and the peripheral device is cleanly divided. For example, statistics are tracked by the host, the device, or the host and the device. A statistic tracked by both the host and peripheral device is divided into non-overlapping portions and combined to produce the statistic. Once an upload is initiated, the device achieves a consistent state and hands delegated states to the stack. Each layer in the stack takes control of its delegated state and resources at the device are freed.

Claims

1. A method to upload an offloaded network stack state object from a first path going from a peripheral device to a switch layer to a second path going from the peripheral device through a plurality of software layers of a network stack to the switch layer, the plurality of software layers including an intermediate layer, the network stack state object having at least one cached state variable and at least one delegated state variable, the method comprising the steps of:

the peripheral device communicating a value of the delegated state variable to the intermediate layer, the value of the delegated state variable controlled by the peripheral device throughout the offload of the network state object;

commanding the intermediate layer to take control of the at least one delegated state variable; and

sending data through the second path based at least in part on the delegated state variable and a value of the cached state variable, the value of the cached state variable controlled by the intermediate layer throughout the offload of the network stack state object.

2. The method of claim 1 further comprising the step of initiating an upload of the offloaded network stack state object.

3. The method of claim 1 wherein the plurality of layers includes a network layer, the peripheral device having a network delegated state, the method further comprising the steps of:

decrementing a count of a number of offloaded transport connections for the network delegated state; and

if the count is decremented to zero;

sending a message to the peripheral device to send the network delegated state to the network layer.

4. The method of claim 1 wherein the plurality of layers includes a framing layer, the peripheral device having a framing delegated state, the method further comprising the steps of:

decrementing a framing count of a number offloaded network layer states for the framing delegated state; and

if the framing count is decremented to zero;

sending a message to the peripheral device to send the framing delegated state to the framing layer.

5. The method of claim 1 further comprising the step of determining if the upload should be initiated.

6. The method of claim 5 wherein the step of determining if the upload should be initiated includes at least one of:

determining if an amount of data being forwarded to the peripheral device is above a maximum threshold;

determining if the peripheral device cannot process a function;

determining if an application is not pre-posting buffers; and

determining if the amount of data being forwarded to the peripheral device is below a minimum bandwidth.

7. A computer storage medium having computer executable instructions for performing the steps of claim 1.

8. The computer storage medium of claim 7 having further computer executable instructions for performing the step of determining if the upload should be initiated, the step of determining if the upload should be initiated includes at least one of;

determining if an amount of data being forwarded to the peripheral device is above the maximum threshold;

determining if the peripheral device cannot process a function;

determining if an application is not pre-posting buffers; and

determining if the amount of data being forwarded to the peripheral device is below a minimum bandwidth.

9. The computer storage medium of claim 7 wherein the plurality of layers includes a network layer and a framing layer, the peripheral device having a network delegated state and a framing delegated state, the computer-readable medium having further computer executable instructions for performing the steps of:

decrementing a count of a number of offloaded transport connections for the network delegated state; and

if the count is decremented to zero;

sending a message to the peripheral device to send the network delegated state to the network layer;

decrementing a framing count of a number offloaded network layer states for the framing delegated state; and

if the framing count is decremented to zero;

sending a message to the peripheral device to send the framing delegated state to the framing layer.

10. A method to upload an offloaded network stack state object and at least one associated protocol from a first path going from a peripheral device to a switch layer to a second path going from the peripheral device through a plurality of software layers of a network stack and the switch layer, the plurality of software layers including an intermediate layer, the network stack state object having a cached state variable and a delegated state variable, the method comprising the steps of:

the peripheral device completing outstanding requests having a transfer status;

handing a value of the delegated state variable from the peripheral device to the switch layer, the value of the delegated state variable controlled by the peripheral device throughout the offload of the network stack state object;

freeing resources in the peripheral device for the intermediate layer; and

sending data through the second path based at least in part on the value of the delegated state variable and a value of the cached state variable, the value of the cached state variable controlled by the intermediate layer throughout the offload of the network stack state object.

11. The method of claim 10 further comprising the step of initiating an upload of the offloaded network stack state object and the at least one associated protocol.

12. The method of claim 10 wherein the plurality of layers includes a network layer, the peripheral device having a network delegated state, the method further comprising the steps of:

sending the network delegated state to the network layer if all offloaded connections from the transport layer have been uploaded.

13. The method of claim 10 wherein the plurality of layers includes a framing layer, the peripheral device having a framing delegated state, the method further comprising the steps of:

sending the framing delegated state to the framing;

layer if all offloaded connections from the network layer have been uploaded.

14. The method of claim 10 further comprising the step of determining if the upload should be initiated.

15. The method of claim 14 wherein the step of determining if the upload should be initiated includes at least one of:

determining if an amount of data being forwarded from the switch layer to the peripheral device is above a maximum threshold;

determining if there is a lack of activity in the offloaded network stack connection;

determining if the peripheral device cannot process a function;

determining if connection behavior is unsuitable for offload;

determining if an upload will enable higher priority state objects to use peripheral device resources if peripheral device resource availability is below a threshold;

determining if an application is not pre-posting buffers; and

determining if the amount of data being forwarded to the peripheral device is above a maximum bandwidth.

16. A computer storage medium having computer executable instructions for performing the step of claim 10.

17. The computer storage medium of claim 16 having further computer executable instructions for performing the step comprising:

determining if the upload should be initiated, the step of determining if the upload should be initiated including at least one of;

determining if an amount of data being forwarded from the switch layer to the peripheral device is above a maximum threshold;

determining if there is a lack of activity in the offloaded network stack connection;

determining if the peripheral device cannot process a function;

determining if connection behavior is unsuitable for offload;

determining if an upload will enable higher priority state objects to use peripheral device resources if peripheral device resource availability is below a threshold;

determining if an application is not pre-posting buffers; and

determining if the amount of data being forwarded to the peripheral device is above a maximum bandwidth.

18. A method of synchronizing an offloaded network stack state object between a host and a peripheral device in a host having a plurality of software layers, each software layer having at least one state variable, the method comprising the steps of:

for each software layer in the plurality of software layers;

classifying the at least one state variable to be one of a constant variable, a cached variable, and a delegated variable;

sending the at least one state variable to the peripheral device;

while the network stacks state object is offloaded, if the at least one state variable has been classified as a cached variable;

controlling a value of the cached variable by the host; and

the host controlling an update of the value of the cached variable in the peripheral device if the cached variable has changed; and

while the network stack state object is offloaded, if the at least one state variable has been classified as a delegated variable;

controlling a value of the at least one state variable by the peripheral device; and

changing the value of the at least one state variable.

19. The method of claim 18 wherein one of the plurality of software layers is a transport layer and wherein the at least one variable is classified as a constant variable, the at least one state variable including at least one of a destination port, a source port, a window scale factor, and an offload handle.

20. The method of claim 18 wherein one of the plurality of software layers is a network layer and wherein the at least one state variable is classified as a constant variable, the at least one state variable including at least one of a destination IP address and a source IP address.

21. The method of claim 18 wherein one of the plurality of software layers is a TCP layer and wherein the at least one state variable is classified as a cached variable, the at least one state variable including at least one of a TCP variable and an IP variable.

22. The method of claim 18 wherein one of the plurality of software layers is a network layer and wherein the at least one state variable is classified as a cached variable, the at least one state variable including an offload handle.

23. The method of claim 18 wherein one of the plurality of software layers is a framing layer and wherein the at least one state variable is classified as a cached variable, the at least one state variable including an ARP address.

24. The method of claim 18 wherein one of the plurality of software layers is an IP security layer and wherein the constant variable includes at least one of a source port, a destination port, a protocol type, and security association variables.

25. The method of claim 18 wherein one of the plurality of software layers is an IP security layer and wherein the cached variable includes at least one of a rekey or byte count, a stop on byte count, a rekey at a predefined tick, a stop at a predefined tick, and a maximum idle time for which a security association may be used.

26. The method of claim 18 wherein one of the plurality of software layers is a TCP layer and wherein the at least one state variable is classified as a delegated variable, the at least one state variable including at least one of a current TCP state, a receive window size, a sequence number for next RECV, a maximum send window, a current congestion window, a maximum sequence number sent, end a sequence number for a next SEND.

27. The method of claim 18 wherein one of the plurality of software layers is a network layer and wherein the at least one state variable is classified as a delegated variable, the at least one state variable including an IP packet id state value.

28. The method of claim 18 wherein one of the plurality of software layers is an IP security layer and wherein the delegated variable includes at least one of a count of the bytes encrypted or decrypted with a security association, a life time of the security association, and an idle time of the security association.

29. A computer storage medium having computer executable instructions for performing the steps of claim 18.

30. The computer storage medium of claim 29 having further computer executable instructions for performing the steps comprising:

processing each delegated variable by the peripheral device; and

for each cached variable;

updating the cached variable if the cached variable has changed.