Method and apparatus for multicast packet reception

• US 8,116,312 B2
• Filed: 02/08/2006
• Issued: 02/14/2012
• Est. Priority Date: 02/08/2006
• Status: Active Grant

• Current Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Original Assignee: SolarFlare Communications Incorporated (Advanced Micro Devices, Inc.)
• Inventors: Riddoch, David J., Pope, Steven L., Porter, Martin W.
• Primary Examiner(s): Moe, Aung S
• Assistant Examiner(s): Elliott, IV, Benjamin H
• Application Number:
  US11/351,177
• Publication Number:
  US 20070183418A1
• Time in Patent Office: 2,197 Days
• Field of Search: 709/250, 709/231, 709/225, 709223-224, 709238-240, 709/246, 709/236, 370/365, 370/377, 370389-392, 370/252, 370/229, 370/395.5, 370/419, 370/402, 370/412, 370/413, 370/469, 713186-189, 713/153, 713/154, 726/22, 726/13
• US Class Current: 370/390
• 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 establishing filtering for incoming data packets to be 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;

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 at least part of a header of the future incoming data packets, including an identification of at least one of the first multicast group and the first user level endpoint, bypasses the operating system network protocol stack,

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 at least part of a header of future incoming data packets of the second multicast group, including an identification of at least one of the second multicast group and the second user level endpoint, bypasses the operating system network protocol stack.

2. A method

for establishing filtering for incoming data packets to be 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;

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 at least part of a header of the future incoming data packets, including an identification of at least one of the first multicast group and the first user level endpoint, bypasses the operating system network protocol stack,

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 further future incoming data packets of the first multicast group also to the second user level endpoint in a manner that at least part of a header of the further future incoming data packets, including an identification of at least one of the first multicast group and the second user level endpoint, bypasses the operating system network protocol stack.

3. The method according to claim 2, 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.

4. The method according to claim 3, wherein the secondary table also identifies endpoint members of a second multicast group.

5. The method according to claim 3, 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.

6. A method

for establishing filtering for incoming data packets to be 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;

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 at least part of a header of the future incoming data packets, including an identification of at least one of the first multicast group and the first user level endpoint, bypasses the operating system network protocol stack,

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.

7. The method according to claim 6, 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.

8. The method according to claim 7, 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.

9. The method according to claim 6, 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.

10. The method according to claim 6, 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.

11. A host system for establishing filtering for incoming data packets to be 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 memor 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 at least part of a header of the future incoming data packets, including an identification of at least one of the first multicast group and the first user level endpoint, bypasses the operating system network protocol stack,

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 at least part of a header of future incoming data packets of the second multicast group, including an identification of at least one of the second multicast group and the second user level endpoint, bypasses the operating system network protocol stack.

12. A host system for establishing filtering for incoming data packets to be 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 memor 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 at least part of a header of the future incoming data packets, including an identification of at least one of the first multicast group and the first user level endpoint, bypasses the operating system network protocol stack,

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 further future incoming data packets of the first multicast group also to the second user level endpoint, in a manner that at least part of a header of the further future incoming data packets, including an identification of at least one of the first multicast group and the second user level endpoint, bypasses the operating system network protocol stack.

13. A host system for establishing filtering for incoming data packets to be 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 at least part of a header of the future incoming data packets, including an identification of at least one of the first multicast group and the first user level endpoint, bypasses the operating system network protocol stack,

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.

14. A system according to claim 13, 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.

15. A system according to claim 13, 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.

16. A system according to claim 13, 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.

17. A method for establishing filtering for incoming data packets to be received by a network interface device from a network and further for filtering incoming data packets received from the network, the network interface device communicating with a host subsystem via a communications bus, the host subsystem having an operating system having a network protocol stack, comprising the steps of:

receiving a first instruction from the host subsystem to deliver future incoming data packets of a first multicast group to a first user level endpoint in the host subsystem, in a manner that at least part of a header of the further future incoming data packets, including an identification of at least one of the first multicast group and the first user level endpoint, bypasses the operating system network protocol stack;

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

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

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;

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

delivering the first incoming data packet to the first user level endpoint in a manner that at least part of a header of the first incoming data packet, including an identification of at least one of the first multicast group and the first user level endpoint, bypasses the operating system network protocol stack; and

delivering the first incoming data packet also to the second user level endpoints, in a manner that at least part of a header of the first incoming data packet, including an identification of at least one of the first multicast group and the second user level endpoint, bypasses the operating system network protocol stack.

18. A method for establishing filtering for incoming data packets to be received by a network interface device from a network, the network interface device communicating with a host subsystem via a communications bus, the host subsystem having an operating system having a network protocol stack, comprising the steps of:

receiving a first instruction from the host subsystem to deliver future incoming data packets of a first multicast group to a first user level endpoint in the host subsystem, in a manner that at least part of a header of the further future incoming data packets, includin an identification of at least one of the first multicast group and the first user level endpoint, bypasses the operating system network protocol stack; 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,

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 subsystem to deliver future incoming data packets of the first multicast group to a second user level endpoint in the host subsystem;

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.

19. A method for establishing filtering for incoming data packets to be received by a network interface device from a network, the network interface device communicating with a host subsystem via a communications bus, the host subsystem having an operating system having a network protocol stack, comprising the steps of:

receiving a first instruction from the host subsystem to deliver future incoming data packets of a first multicast group to a first user level endpoint in the host subsystem, in a manner that at least part of a header of the further future incoming data packets, including an identification of at least one of the first multicast group and the first user level endpoint, bypasses the operating system network protocol stack;

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;

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

20. Network interface apparatus, for use with a host subsystem in communication with the network interface apparatus via an internal communications bus of the host subsystem, the host subsystem having an operating system having a network protocol stack, the network interface device comprising:

a filter for filtering incoming data packets received from the network, the filter comprising a table; and

a resource configuration unit that, in response to receipt from the host subsystem via the communications bus of first and second instructions to deliver future incoming data packets of a first multicast group to respective first and second user level endpoints in the host subsystem, configures the filter table in the network interface device with a correspondence of an identification of both the first and second user level endpoints, on the one hand, with an identification of the first multicast group, on the other hand,

wherein in response to receipt from the host subsystem, while the first and second correspondences remains valid in the table, of a third instruction from the host subsystem 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 the resource configuration unit deletes from the table, the correspondence of the first multicast group with the identified one of the first and second user level endpoints.

21. Network interface apparatus, for use with a host subsystem in communication with the network interface apparatus via an internal communications bus of the host subsystem, the host subsystem having an operating system having a network protocol stack,

the network interface apparatus comprising a filter for filtering incoming data packets received from the network, the filter comprising a filter table,

the network interface apparatus being configured to, in response to receipt from the network of an incoming data packet of a first multicast group, to deliver the data packet via the communications bus to each of a plurality of user level processes each identified in the filter table, bypassing the operating system,

the network interface apparatus being further configured to determine if the following conditions are fulfilled:

the incoming data packet is not malformed,

the incoming data packet uses a protocol that is supported in the filter table, and

at least one correspondence is found between the incoming data packet and at least one user level endpoint;

and if all of the conditions are fulfilled, the network interface apparatus delivering the incoming data packet to each of the plurality of user level processes, and otherwise, delivering the incoming data packet to the operating system.