Method and apparatus for multicast packet reception

• US 20070183418A1
• Filed: 02/08/2006
• Published: 08/09/2007
• Est. Priority Date: 02/08/2006
• Status: Active Grant

• Current Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Original Assignee: Level 5 Networks, Inc. (Advanced Micro Devices, Inc.)
• Inventors: Riddoch, David, Pope, Steven, Porter, Martin
• Granted Patent: US 8,116,312 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 49/90 Buffering arrangements

Abstract

Roughly described, incoming data packets are delivered by the NIC directly to at least two user level endpoints. In an aspect, only filters that cannot be ambiguous are created in the NIC. In another aspect, the NIC maintains a filter table supporting direct delivery of incoming unicast and multicast data packets to one user level endpoint. Additional requests to join the same multicast group cause replacement of the NIC filter with one in the kernel. In another aspect, a NIC has limited capacity to maintain multicast group memberships. In response to a new multicast filter request, the kernel establishes it in the NIC only if the NIC still has sufficient capacity; otherwise it is established in the kernel.

Claims

1. A method for filtering incoming data packets received from a network, for use with an operating system and a network interface device, comprising the steps of:

receiving a first request to deliver a future incoming data packet to a first user level endpoint, the first request indicating first packet header properties to look for;

determining from the first packet header properties whether they are of a character that permits a user level process to make a second request to deliver the future incoming data packet also to a second user level endpoint;

programming a network interface device to deliver a future incoming data packet having the first packet header properties to the first user level endpoint, only if the first packet header properties are not of such a character.

2. A method according to claim 1, further comprising the step of, if the first packet header properties are of such a character, causing the operating system to deliver to the first user level endpoint a future incoming data packet having the first packet header properties.

3. A method according to claim 1, wherein the first request comprises a request to join a multicast group, the first packet header properties including a destination IP address matching the multicast group address,

and wherein the step of determining determines that the first packet header properties are of a character that permits a user level process to make a second request to deliver the future incoming data packet also to a second user level endpoint.

4. A method according to claim 1, wherein the step of determining determines that the first packet header properties are not of a character that permits a user level process to make a second request to deliver the future incoming data packet also to a second user level endpoint.

5. A method according to claim 4, wherein the first request comprises a recv( ) or recvFrom( ) call.

6. A method according to claim 4, further comprising the step of, where other reasons exist for not programming the network interface device to deliver a future incoming data packet having the first packet header properties to the first user level endpoint, causing the operating system to deliver to the first user level endpoint a future incoming data packet having the first packet header properties.

7. A method according to claim 1, wherein the first request is to deliver to the first user level endpoint a stream of future incoming data packets all having the first packet header properties.

8. A system for filtering incoming data packets received from a network, for use with a network interface device, comprising:

a memory subsystem; and

a data processor coupled to the memory subsystem, the data processor configured to;

receive a first request from a user level process to deliver a future incoming data packet to a first user level endpoint, the first request indicating first packet header properties to look for;

determine from the first packet header properties whether they are of a character that permits a user level process to make a second request to deliver the future incoming data packet also to a second user level endpoint; and

only if the first packet header properties are not of such a character, program the network interface device to deliver a future incoming data packet having the first packet header properties to the first user level endpoint.

9. A method for filtering incoming data packets received from a network, for use with a network interface device by a host system having an operating system having a network protocol stack, comprising the steps of:

receiving a first request for a first user level endpoint to join a first multicast group; and

programming the network interface device to deliver future incoming data packets of the first multicast group to the first user level endpoint in a manner that bypasses the operating system network protocol stack.

10. A method according to claim 9, further comprising the steps of:

receiving, while the first user level endpoint remains a member of the first multicast group, a second request for a second user level endpoint to join a second multicast group; and

programming the network interface device to deliver future incoming data packets of the second multicast group to the second user level endpoint in a manner that bypasses the operating system network protocol stack.

11. A method according to claim 9, further comprising the steps of:

receiving, while the first user level endpoint remains a member of the first multicast group, a second request for a second user level endpoint to join the first multicast group; and

programming the network interface device to deliver future incoming data packets of the first multicast group also to the second user level endpoint in a manner that bypasses the operating system network protocol stack.

12. A method according to claim 11, wherein the step of programming the network interface device to deliver also to the second user level endpoint, comprises the steps of:

programming into a secondary table in the network interface device of endpoint members of the first multicast group, an identification of the second user level endpoint; and

programming the network interface device to refer to the secondary table in response to an incoming data packet of the first multicast group.

13. A method according to claim 12, wherein the secondary table also identifies endpoint members of a second multicast group.

14. A method according to claim 12, wherein the network interface device includes a filter table that maintains, for each of a plurality of packet header match criteria, identification of a single corresponding packet destination endpoint for incoming data packets matching the corresponding packet header match criteria,

and wherein the step of programming the network interface device to deliver future incoming data packets to the first user level endpoint, comprises the step of programming into the filter table an identification of the first user level endpoint as the single corresponding packet destination endpoint for incoming data packets having a destination IP address matching that of the first multicast group,

further comprising the steps of:

programming an identification of the first user level endpoint into the secondary table of endpoint members of the first multicast group; and

unprogramming from the filter table the identification of the first user level endpoint as the single corresponding packet destination endpoint for incoming data packets having a destination IP address matching that of the first multicast group.

15. A method according to claim 9, wherein the network interface device includes a filter table that maintains, for each of a plurality of packet header match criteria, identification of a single corresponding packet destination endpoint for incoming data packets matching the corresponding packet header match criteria,

and wherein the step of programming the network interface device to deliver future incoming data packets to the first user level endpoint, comprises the step of programming into the filter table an identification of the first user level endpoint as the single corresponding packet destination endpoint for incoming data packets having a destination IP address matching that of the first multicast group.

16. A method according to claim 9, further comprising the steps of:

receiving a second request for a second user level endpoint to join the first multicast group;

making a determination that the network interface device lacks sufficient capacity to be programmed to add the second user level endpoint as an endpoint for delivery of future incoming data packets of the first multicast group; and

causing the operating system to deliver to the second user level endpoint, future incoming data packets of the first multicast group.

17. A method according to claim 16, further comprising the steps of:

causing the network interface device to deliver future incoming data packets of the first multicast group to the operating system and not to the first user level endpoint; and

causing the operating system to deliver future incoming data packets of the first multicast group, to the first user level endpoint.

18. A method according to claim 17, wherein the network interface device delivers all incoming multicast data packets to the operating system unless programmed otherwise,

wherein the step of programming the network interface device to deliver to the first user level endpoint future incoming data packets of the first multicast group causes the network interface device to deliver future incoming data packets of the first multicast group to the first user level endpoint and not to the operating system,

and wherein the step of causing the network interface device to deliver future incoming data packets of the first multicast group to the operating system and not to the first user level endpoint, comprises the step of unprogramming the network interface device to deliver to the first user level endpoint future incoming data packets of the first multicast group.

19. A method according to claim 16, further comprising the steps of:

receiving a third request for a third user level endpoint to join the first multicast group; and

in response to a determination that the operating system is already handling deliveries of incoming data packets of the first multicast group, causing the operating system to deliver future incoming data packets of the first multicast group also to the third user level endpoint.

20. A method according to claim 16, further comprising the steps of:

receiving a request for a particular user level endpoint to leave the first multicast group;

making a determination that the network interface device has sufficient capacity to be programmed for delivery of future incoming data packets of the first multicast group to all user level endpoints of the host that remain as members of the first multicast group; and

causing the network interface device to deliver future incoming data packets of the first multicast group to each of the remaining user level endpoints and not to the operating system.

21. A method according to claim 9, further comprising the steps of:

receiving a second request for a second user level endpoint to join the first multicast group;

causing the network interface device to deliver future incoming data packets of the first multicast group to the operating system and not to the first user level endpoint; and

causing the operating system to deliver future incoming data packets of the first multicast group, to both the first and second user level endpoints.

22. A method according to claim 21, further comprising the steps of:

receiving a third request for a third user level endpoint to join the first multicast group; and

causing the operating system to deliver future incoming data packets of the first multicast group also to the third user level endpoint.

23. A method according to claim 21, further comprising the steps of:

receiving a request for the first a particular user level endpoint to leave the first multicast group;

in response to a determination that only one user level endpoint of the host computer system remains a member of the first multicast group, causing the network interface device to deliver future incoming data packets of the first multicast group to the remaining user level endpoint and not to the operating system.

24. A method according to claim 9, wherein the first user level endpoint comprises a user level receive queue.

25. A host system for filtering incoming data packets received from a network, for use with a network interface device, the host system being configured to have an operating system having a network protocol stack, comprising:

a memory subsystem; and

a data processor coupled to the memory subsystem, the data processor configured to, in response to a first request for a first user level endpoint to join a first multicast group, program the network interface device to deliver future incoming data packets of the first multicast group to the first user level endpoint in a manner that bypasses the operating system network protocol stack.

26. A system according to claim 25, wherein the data processor is further configured to, in response to a second request for a second user level endpoint to join a second multicast group, received while the first user level endpoint remains a member of the first multicast group, program the network interface device to deliver future incoming data packets of the second multicast group to the second user level endpoint in a manner that bypasses the operating system network protocol stack.

27. A system according to claim 25, wherein the data processor is further configured to, in response to a second request for a second user level endpoint to join the first multicast group, received while the first user level endpoint remains a member of the first multicast group, program the network interface device to deliver future incoming data packets of the first multicast group also to the second user level endpoint, bypassing the operating system network protocol stack.

28. A system according to claim 25, wherein the data processor is further configured to, in response to a second request for a second user level endpoint to join the first multicast group:

make a determination that the network interface device lacks sufficient capacity to be programmed to add the second user level endpoint as an endpoint for delivery of future incoming data packets of the first multicast group; and

in response to the determination, cause the operating system to deliver future incoming data packets of the first multicast group to the second user level endpoint.

29. A system according to claim 28, wherein the data processor is further configured to, in further response to the determination:

cause the network interface device to deliver future incoming data packets of the first multicast group to the operating system and not to the first user level endpoint; and

cause the operating system to deliver future incoming data packets of the first multicast group, to the first user level endpoint.

30. A system according to claim 28, wherein the data processor is further configured to, in response to a third request for a third user level endpoint to join the first multicast group, and in response to a determination that the operating system is already handling deliveries of incoming data packets of the first multicast group, cause the operating system to deliver future incoming data packets of the first multicast group also to the third user level endpoint.

31. A system according to claim 28, wherein the data processor is further configured to, in response to a request for a particular user level endpoint to leave the first multicast group:

make a determination that the network interface device has sufficient capacity to be programmed for delivery of future incoming data packets of the first multicast group to all user level endpoints of the host that remain as members of the first multicast group; and

in response to the determination, cause the network interface device to deliver future incoming data packets of the first multicast group to each of the remaining user level endpoints and not to the operating system.

32. A system according to claim 25, wherein the data processor is further configured to, in response to a second request for a second user level endpoint to join the first multicast group:

cause the network interface device to deliver future incoming data packets of the first multicast group to the operating system and not to the first user level endpoint; and

cause the operating system to deliver future incoming data packets of the first multicast group, to both the first and second user level endpoints.

33. A system according to claim 32, wherein the data processor is further configured to, in response to a request for the first a particular user level endpoint to leave the first multicast group, and further in response to a determination that only one user level endpoint of the host computer system remains a member of the first multicast group, cause the network interface device to deliver future incoming data packets of the first multicast group to the remaining user level endpoint and not to the operating system.

34. A system according to claim 25, wherein the first user level endpoint comprises a user level receive queue.

35. Network interface apparatus, for use with a network and with a host subsystem in communication with the network interface apparatus via a communications bus, the host subsystem being capable of running an operating system having a network protocol stack and at least one user level process collectively having a plurality of user level endpoints for receipt of data packets incoming from the network interface apparatus, the network interface apparatus comprising a table having capacity to identify at least two user level endpoints for receipt of incoming data packets matching a single set of filter criteria.

36. Apparatus according to claim 35, wherein the table has capacity to identify at least two user level endpoints for receipt of data packets of a single multicast group received from a network.

37. Apparatus according to claim 35, further comprising the host subsystem.

38. Apparatus according to claim 35, wherein the table identifies at least two user level endpoints for receipt of incoming data packets matching a single set of filter criteria.

39. Apparatus according to claim 38, further comprising means for delivering a data packet matching the single set of filter criteria, incoming from the network, to each of the user level endpoints identified in the table as being for receipt of incoming data packets matching the single set of filter criteria.

40. Apparatus according to claim 35, wherein the table has capacity to identify, for of each of a plurality of multicast groups, at least two user level endpoints for delivery of incoming data packets of each single one of the multicast groups.

41. Apparatus according to claim 40, wherein the table further has capacity to identify user level endpoints for delivery of incoming unicast data packets.

42. A method for filtering incoming data packets received from a network, for use by a network interface device with a host system having an operating system having a network protocol stack, comprising the steps of:

receiving a first instruction from the host system to deliver future incoming data packets of a first multicast group to a first user level endpoint in the host system; and

programming a table in the network interface device with a first correspondence of an identification of the first user level endpoint with an identification of the first multicast group.

43. A method according to claim 42, further comprising the steps of:

receiving, while the first correspondence remains valid in the table, a second instruction from the host system to deliver future incoming data packets of the first multicast group to a second user level endpoint in the host system; and

further programming the table in the network interface device with a second correspondence of an identification of the second user level endpoint with an identification of the first multicast group.

44. A method according to claim 43, further comprising the steps of:

receiving from the network a first incoming data packet of the first multicast group; and

delivering the first incoming data packet to both the first and second user level endpoints, both bypassing the operating system network protocol stack.

45. A method according to claim 43, further comprising the steps of:

receiving, while the first and second correspondences remain valid in the table, a third instruction from the host system to no longer deliver future incoming data packets of the first multicast group to an identified one of the first and second user level endpoints; and

deleting from the table, the correspondence of the first multicast group with the identified one of the first and second user level endpoints.

46. A method according to claim 42, wherein the table includes a primary table and a secondary table,

and wherein the step of programming the table with the first correspondence comprises the step of programming the first correspondence into the primary table;

further comprising the steps of;

receiving, while the first correspondence remains valid in the primary table, a second instruction from the host system to deliver future incoming data packets of the first multicast group to a second user level endpoint in the host system;

programming into the secondary table both the first correspondence and a second correspondence of an identification of the second user level endpoint with an identification of the first multicast group; and

unprogramming the first correspondence from the primary table.

47. A method according to claim 42, further comprising the steps of:

receiving a second instruction from the host system to deliver future incoming unicast data packets having indicated second header characteristics to a second user level endpoint in the host system; and

further programming the table in the network interface device with a second correspondence of an identification of the second user level endpoint with an identification of the second header characteristics.

48. Network interface apparatus, for use with a host system having an operating system having a network protocol stack, comprising:

means, operative in response to receipt from the host system of a first instruction to deliver future incoming data packets of a first multicast group to a first user level endpoint in the host system, for programming a table in the network interface device with a first correspondence of an identification of the first user level endpoint with an identification of the first multicast group.

49. Apparatus according to claim 48, further comprising:

means, operative in response to receipt from the host system, while the first correspondence remains valid in the table, of a second instruction to deliver future incoming data packets of the first multicast group to a second user level endpoint in the host system, for further programming the table in the network interface device with a second correspondence of an identification of the second user level endpoint with an identification of the first multicast group.

50. Apparatus according to claim 49, further comprising:

means, operative in response to receipt from the network a first incoming data packet of the first multicast group, for delivering the first incoming data packet to both the first and second user level endpoints, both bypassing the operating system network protocol stack.

51. Apparatus according to claim 49, further comprising:

means, operative in response to receipt from the host system, while the first and second correspondences remains valid in the table, of a third instruction from the host system to no longer deliver future incoming data packets of the first multicast group to an identified one of the first and second user level endpoints; and

means for deleting from the table, the correspondence of the first multicast group with the identified one of the first and second user level endpoints.

52. A method for filtering incoming data packets received from a network, for use by a network interface device with a host system having an operating system having a network protocol stack, comprising the steps of:

receiving an incoming data packet of a first multicast group; and

delivering the data packet to a first user level process, bypassing the operating system.

53. Network interface apparatus, for use with a network and a host system having an operating system having a network protocol stack, comprising:

means, operative in response to receipt from the network of an incoming data packet of a first multicast group, for delivering the data packet to a first user level process, bypassing the operating system.

54. A method for filtering incoming data packets received from a network, for use by a network interface device with a host system having an operating system having a network protocol stack, comprising the steps of:

receiving a first data packet incoming from the network; and

delivering the first data packet to each of a plurality of user level processes, all bypassing the operating system.

55. Network interface apparatus, for use with a network and a host system having an operating system having a network protocol stack, comprising:

means, operative in response to receipt from the network of a first data packet incoming from the network, for delivering the first data packet to each of a plurality of user level processes, all bypassing the operating system.