PROTOCOL DATA UNIT INTERFACE

• US 20150085878A1
• Filed: 10/24/2013
• Published: 03/26/2015
• Est. Priority Date: 09/26/2013
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Kangarlou, Ardalan, Strunk, John David
• Granted Patent: US 9,398,117 B2
• Time in Patent Office: Days
• US Class Current: 370/469
• CPC Class Codes: H04L 41/0226 Mapping or translating multiple network management protocols
• CPC Class Codes: H04L 49/9047 including multiple buffers, e.g. buffer pools
• CPC Class Codes: H04L 49/9057 Arrangements for supporting packet reassembly or resequencing
• CPC Class Codes: H04L 69/18 Multiprotocol handlers, e.g. single devices capable of handling multiple protocols
• CPC Class Codes: H04L 69/321 Interlayer communication protocols or service data unit [SDU] definitions; Interfaces between layers
• CPC Class Codes: H04L 69/322 Intralayer communication protocols among peer entities or protocol data unit [PDU] definitions

Abstract

An interface can be designed that efficiently constructs descriptors for streams of protocol data units (PDUs) and provides coherent views of the PDUs and the PDU stream for a requesting application regardless of location within a buffer pool for PDUs. The interface creates a descriptor for each PDU written into the buffer pool and links the descriptors in accordance with the appropriate order of the corresponding PDUs. The interface can create PDU descriptors hierarchically. For instance, a PDU descriptor for a PDU of a layer N protocol can refer to one or more PDU descriptors of a layer N−1 protocol.

Claims

1. A method comprising:

while protocol data units of a first protocol are received and written into a buffer pool, creating a first protocol descriptor for each protocol data unit of the first protocol responsive to determining that the protocol data unit has been written into the buffer pool, wherein the first protocol descriptor is created with at least an indication of a memory location where the protocol data unit has been written within the buffer pool;

maintaining an order for the first protocol descriptors in accordance with an order of the protocol data units as indicated by the protocol data units;

creating second protocol descriptors for protocol data units of a second protocol, wherein each of the second protocol descriptors is created with a reference to at least one of the first protocol descriptors; and

providing access to payloads of the protocol data units of the first protocol in the buffer pool with the second protocol descriptors.

2. The method of claim 1 further comprising providing a coherent view of protocol data units of the second protocol with the second protocol descriptors.

3. The method of claim 1 further comprising reassembling the protocol data units of the second protocol via the second protocol descriptors and the first protocol descriptors.

4. The method of claim 1 further comprising detecting writing of each of the protocol data units of the first protocol into the buffer pool.

5. The method of claim 4, wherein said detecting writing of each of the protocol data units of the first protocol into the buffer pool comprises one of polling a component of a layer of an implemented network stack and receiving an interrupt message from the component of the layer of the implemented network stack.

6. The method of claim 1, wherein said maintaining the order for the first protocol descriptors in accordance with the order of protocol data units as indicated by the protocol data units comprises:

for each of the protocol data units of the first protocol, examining a header of the protocol data unit for sequence information about the protocol data unit and creating the first protocol descriptor that references the protocol data unit in accordance with the sequence information with respect other first protocol descriptors.

7. The method of claim 1, wherein said creating the second protocol descriptors for the protocol data units of the second protocol comprises:

accessing payloads of the protocol data units in the buffer pool via the first protocol descriptors; and

identifying the protocol data units of the second protocol within the payloads.

8. The method of claim 7 further comprising determining a characteristic for identifying a protocol data unit of the second protocol prior to creating the second protocol descriptors, wherein said identifying the protocol data units of the second protocol within the payloads comprises examining each of the payloads for the characteristic.

9. A computer readable storage medium having stored thereon computer executable program instructions for creating a hierarchy of descriptors for protocol data units of different protocols, the program instructions to:

create, as a first level of the hierarchy, a first sequence of descriptors for a stream of protocol data units received by a component of a first protocol of a network stack, the program instructions to create the first sequence of descriptors coincident with writing of the stream of protocol data units into a plurality of memory locations by the component of the first protocol;

indicate, in each of the first sequence of descriptors, where the corresponding one of the protocol data units of the first protocol has been written into the plurality of memory locations;

maintain the first sequence of descriptors in an order according to an order indicated by the protocol data units in the stream of protocol data units;

access payloads of the stream of protocol data units via the first sequence of descriptors and determine data of the payloads that form protocol data units of a second protocol of the network stack; and

create, as a second level of the hierarchy, a second sequence of descriptors for the protocol data units of the second protocol, the program instructions to create each of the second sequence of descriptors with an indication of those of the first sequence of descriptors that indicate a protocol data unit with a payload that forms at least part of a corresponding one of the protocol data units of the second protocol represented by the descriptor of the second sequence of descriptors.

10. The computer readable storage medium of claim 9, wherein the program instructions further comprise program instructions to indicate, in each of the first sequence of descriptors, information from a corresponding one of the stream of protocol data units.

11. The computer readable storage medium of claim 9, wherein the program instructions further comprise program instructions to indicate, in each of the second sequence of descriptors, information from a corresponding one of the protocol data units of the second protocol.

12. The computer readable storage medium of claim 9, wherein the program instructions to create the second sequence of descriptors for the protocol data units of the second protocol comprise program instructions to determine a characteristic of a beginning of a protocol data unit of the second protocol and to examine the payloads for the characteristic.

13. The computer readable storage medium of claim 9 further comprising program instructions to determine the second protocol specified in a request and invoke the program instructions to create the second sequence of descriptors in response to determining the second protocol specified in the request.

14. A computer program product comprising:

a computer readable storage medium having computer usable program code embodied therewith, the computer usable program code comprising computer usable program code to;

create a plurality of descriptors linking a plurality of protocol data units together in sequential order, wherein each of the plurality of descriptors comprises a respective data structure;

create one or more higher-level descriptors, wherein each higher-level descriptor of the one or more higher-level descriptors comprises a respective data structure, wherein each higher-level descriptor of the one or more higher-level descriptors comprises one or more references to one or more descriptors of the plurality of descriptors; and

receive one or more requests for data, wherein the requests for data specify at least one of data from one or more protocol data units of the plurality of protocol data units or the data representing one or more higher-level protocol data units.

15. The computer program product of claim 14, wherein the computer usable program code further comprises computer usable program code to:

in response to receiving the one or more requests for data, send at least one of;

a descriptor of the plurality of descriptors,

a reference to a descriptor of the plurality of descriptors,

a message descriptor of the one or more message descriptors,

a reference to a higher-level descriptor of the one or more higher-level descriptors, and

data representing one or more protocol data units of the plurality of protocol data units.

16. The computer program product of claim 14, wherein the computer usable program code to create a plurality of descriptors linking a plurality of protocol data units together in sequential order comprises computer usable program code to:

determine that a protocol data unit has been written into a buffer;

create a protocol data unit descriptor, wherein the protocol data unit descriptor comprises a data structure;

extract a set of values from the protocol data unit; and

populate the protocol data unit descriptor with the set of values from the protocol data unit and a reference to the protocol data unit.

17. The computer program product of claim 14, wherein the protocol data unit comprises one of a frame, a packet, and a message.

18. The computer program product of claim 14, wherein the computer usable program code to create one or more higher-level descriptors further comprises computer usable program code to:

create a first higher-level descriptor of the plurality of higher-level descriptors;

locate a first descriptor of the plurality of descriptors associated with a protocol data unit of the plurality protocol data units that includes the start of a higher-level protocol data unit;

locate a second descriptor of the plurality of descriptors associated with a protocol data unit of the plurality of protocol data units that includes the end of a higher-level protocol data unit; and

write an indication of the first descriptor and an indication of the second descriptor into the first higher-level descriptor.

19. The computer program product of claim 18, wherein the computer usable program code further comprises computer usable program code to write an indication for each descriptor of the plurality of descriptors that link the first descriptor to the second descriptor.

20. The computer program product of claim 14, wherein the computer usable program code further comprises computer usable code to:

in response to receipt of one or more requests for data, traverse a reference from a first higher-level descriptor of the one or more higher-level descriptors to a first descriptor of the plurality of descriptors, wherein the first descriptor is associated with a beginning of a higher-level protocol data unit;

traverse a series of one or more references from the first descriptor of the plurality of descriptors to a second descriptor of the plurality of descriptors, wherein the second descriptor is associated with an end of the higher-level protocol data unit; and

for each traversed descriptor of the plurality of descriptors from the first descriptor to the second descriptor,

traverse a reference from the current descriptor to a protocol data unit; and

read the protocol data unit.