Method and apparatus for describing multiple packets to hardware

• US 7,356,039 B1
• Filed: 09/22/2003
• Issued: 04/08/2008
• Est. Priority Date: 06/12/2002
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: DiMambro, Francesco R.
• Primary Examiner(s): Orgad; Edan
• Assistant Examiner(s): Burrowes; Lawrence J
• Application Number:
  US10/667,562
• Time in Patent Office: 1,660 Days
• Field of Search: 370/411, 370/471, 370/475, 370/473
• US Class Current: 370/411
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 49/901 using storage descriptor, e.g. read or write pointers
• CPC Class Codes: H04L 49/9042 Separate storage for different parts of the packet, e.g. header and payload
• 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 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A system and method for describing multiple packets to a communication module or device without requiring descriptors for each packet. A device driver for the communication apparatus receives a set of packet headers and a set of packet payloads from an upper layer protocol. The headers may be received in a header buffer, and the payloads may be received in a separate data buffer. Or, the packets may be received, in assembled form, in a single buffer. The device driver configures a single descriptor to describe the multiple packets to the communication apparatus. The descriptor includes base address(es) of the buffer(s) in which the headers, payloads or assembled packets are stored, and the lengths of the individual headers, payloads or assembled packets. If the buffer contents are not packed, the descriptor may also include offsets of the headers, payloads or packets.

Claims

1. A method of describing multiple packets to a communication apparatus with a single descriptor, the method comprising:

receiving a header buffer comprising a header for each of N packets, wherein N>

1;

receiving a data buffer comprising a payload for each of said N packets;

in a single descriptor configured to be read by the communication apparatus, storing;

a base address of said header buffer;

a base address of said data buffer;

a checksum start offset indicating where to compute a checksum on each of said N packets;

a checksum stuff offset indicating where to store the checksum in each of said N packets; and

for each of said N packets;

a length of the payload for said packet;

a sample of the payload for said packet; and

a length of the header for said packet.

2. The method of claim 1, further comprising:

storing in said single descriptor;

a first indicator configured to indicate whether the headers for said N packets are packed in said header buffer; and

a second indicator configured to indicate whether the payloads for said N packets are packed in said data buffer.

3. The method of claim 1, further comprising:

storing in said single descriptor, for each of said N packets, an offset of the packet'"'"'s header within said header buffer.

4. The method of claim 1, further comprising:

storing in said single descriptor, for each of said N packets, an offset of the packet'"'"'s payload within said data buffer.

5. The method of claim 1, wherein the communication apparatus is configured for InfiniBand, the method further comprising:

storing in said single descriptor;

an R_key for said header buffer; and

an R_key for said data buffer.

6. A computer readable medium storing instructions that, when executed by a computer, cause the computer to perform a method of describing multiple packets to a communication apparatus with a single descriptor, the method comprising:

receiving a header buffer comprising a header for each of N packets, wherein N>

1;

receiving a data buffer comprising a payload for each of said N packets;

in a single descriptor configured to be read by the communication apparatus, storing;

a base address of said header buffer;

a base address of said data buffer;

a checksum start offset indicating where to compute a checksum on each of said N packets;

a checksum stuff offset indicating where to store the checksum in each of said N packets; and

for each of said N packets;

a length of the payload for said packet;

a sample of the payload for said packet; and

a length of the header for said packet.

7. A processor-implementable method of using a single descriptor to facilitate the passing of multiple packets to a communication apparatus from a device driver, the method comprising:

storing multiple packets'"'"' headers contiguously within a header buffer;

storing payloads of the multiple packets contiguously within a data buffer;

providing said header buffer and said data buffer to the device driver for the communication apparatus;

configuring the single descriptor to describe the multiple packets, wherein configuring the single descriptor comprises including in the single descriptor;

a base address of said header buffer;

a base address of said data buffer;

for each packet in the multiple packets;

a length of a header of the packet; and

a length of a payload of the packet;

a checksum start value configured to indicate where, in each of the multiple packets, a checksum computation is to be initiated; and

a checksum stuff value configured to indicate where, in each of the multiple packets, a checksum computation is to be stored;

configuring a second descriptor to reference said single descriptor, wherein said second descriptor is a traditional descriptor configured to describe a single packet;

passing said single descriptor and the second descriptor to the communication apparatus; and

at the communication apparatus, reading the second descriptor to access said single descriptor, and using said single descriptor to transmit the multiple packets.

8. The method of claim 7, wherein configuring the single descriptor further comprises including in the single descriptor:

a packed header indicator configured to indicate whether the multiple packets'"'"' headers are packed in said header buffer; and

a packed data indicator configured to indicate whether the multiple packets'"'"' payloads are packed in said data buffer.

9. The method of claim 7, wherein configuring the single descriptor further comprises including in the single descriptor:

for each packet in the multiple packets, a sample of the packet'"'"'s payload.

10. A computer readable medium storing instructions that, when executed by a computer, cause the computer to perform a method of using a single descriptor to facilitate the passing of multiple packets to a communication apparatus from a device driver, the method comprising:

storing multiple packets'"'"' headers contiguously within a header buffer;

storing payloads of the multiple packets contiguously within a data buffer;

providing said header buffer and said data buffer to the device driver for the communication apparatus;

configuring the single descriptor to describe the multiple packets, wherein configuring the single descriptor comprises including in the single descriptor;

a base address of said header buffer;

a base address of said data buffer;

for each packet in the multiple packets;

a length of a header of the packet; and

a length of a payload of the packet;

a checksum start value configured to indicate where, in each of the multiple packets, a checksum computation is to be initiated; and

a checksum stuff value configured to indicate where, in each of the multiple packets, a checksum computation is to be stored;

configuring a second descriptor to reference said single descriptor, wherein said second descriptor is a traditional descriptor configured to describe a single packet;

passing said single descriptor and the second descriptor to the communication apparatus; and

at the communication apparatus, reading the second descriptor to access said single descriptor, and using said single descriptor to transmit the multiple packets.

11. A computer readable medium containing a data structure configured to describe multiple packets to a communication apparatus for transmitting the multiple packets, the data structure comprising:

a base address of a header buffer storing headers for the multiple packets;

a base address of a data buffer storing payloads for the multiple packets;

for each packet in the multiple packets;

a length of a header of the packet; and

a length of a payload of the packet;

a checksum start value configured to indicate where, in each of the multiple packets, a checksum computation is to be initiated;

a checksum stuff value configured to indicate where, in each of the multiple packets, a checksum computation is to be stored

a first indicator configured to indicate whether the headers are stored contiguously in said header buffer; and

a second indicator configured to indicate whether the payloads are stored contiguously in said data buffer.

12. An apparatus for transmitting packets, comprising:

a reader module configured to read a single descriptor configured to describe multiple packets, wherein said single descriptor comprises;

a base address of a header buffer storing headers for the multiple packets;

a base address of a data buffer storing payloads for the multiple packets;

for each packet in the multiple packets;

a length of a header of the packet; and

a length of a payload of the packet;

a first indicator configured to indicate whether the headers are stored contiguously in said header buffer; and

a second indicator configured to indicate whether the payloads are stored contiguously in said data buffer;

a retrieval module configured to retrieve the multiple packets, wherein said retrieval module comprises;

a header retriever configured to retrieve headers for the multiple packets; and

a payload retriever configured to retrieve payloads for the multiple packets; and

a transmitter module configured to transmit the multiple packets.

13. A method of describing multiple packets to a communication apparatus, the method comprising:

for each packet, configuring a first data structure to identify;

a header length;

a payload length;

a checksum start value configured to indicate where, in each of the multiple packets, a checksum computation is to be initiated;

a checksum stuff value configured to indicate where, in each of the multiple packets, a checksum computation is to be stored; and

a type of checksum;

storing in the first data structure headers for the packets and payloads for a subset of the packets;

configuring a first descriptor to identify the first data structure;

configuring said first descriptor to identify a location of the headers and a location of the payloads within the first data structure;

storing in a second data structure payloads for a subset of the packets;

configuring a second descriptor to identify a location of the payloads within the second data structure; and

forwarding said first descriptor and said second descriptor to the communication apparatus to facilitate transmission of the packets.

14. A computer readable medium containing data structures for facilitating transmission of multiple packets from a communication apparatus, the data structures comprising:

a first metadata structure configured to include;

a metadata section configured to identify, for each of the multiple packets;

a header length; and

a payload length; and

a header section configured to store headers for the multiple packets;

a first descriptor configured to identify;

a memory location of said first metadata structure; and

a location of said header section within said first metadata structure; and

a checksum start value configured to indicate where, in each of the multiple packets, a checksum computation is to be initiated; and

a checksum stuff value configured to indicate where, in each of the multiple packets, a checksum computation is to be stored.

15. The computer readable medium of claim 14, further comprising:

a second metadata structure configured to store payloads for the multiple packets; and

a second descriptor configured to identify a memory location of said second metadata structure.

16. The computer readable medium of claim 14, wherein:

said first metadata structure is further configured to include;

a payload section configured to store payloads for the multiple packets; and

said first descriptor is further configured to identify;

a location of said payload section within said first metadata structure.

17. The computer readable medium of claim 14, wherein:

said first metadata structure is further configured to identify;

a type of checksum for checksumming the multiple packets.