Egress packet processing using a modified packet header separate from a stored payload

Patent metadata

Field	Value
Publication number	US-11075859-B2
Application number	US-202016746355-A
Country	US
Kind code	B2
Filing date	Jan 17, 2020
Priority date	May 18, 2016
Publication date	Jul 27, 2021
Grant date	Jul 27, 2021

Abstract

At least a payload of a packet that is received by a network device is stored in a packet memory. The packet is processed at least to determine at least one egress port via which the packet is to be transmitted, modify a header of the packet to generate a modified header, and determine, based at least in part on the modified header, whether the packet is to be transmitted or to be discarded by the network device. In response to determining that the packet is to be transmitted, the at least the payload of the packet is retrieved from the packet memory, a transmit packet is generated at least by combining the at least the payload of the packet with the modified header, and the transmit packet is transmitted via the determined at least one egress port of the network device.

First claim

What is claimed is:

1. A method for processing packets in a network device, the method comprising:
receiving, at the network device, a packet from a network;
storing, with the network device, at least a payload of the packet in a packet memory of the network device;
processing, with a packet processor of the network device, the packet, the processing including at least i) determining at least one egress port via which the packet is to be transmitted by the network device, ii) modifying one or more fields in a header of the packet to generate a modified header that is indicative of an access control policy applying to the packet, and iii) determining, based at least in part on application of the access control policy indicated by the one or more modified fields of the header, whether the packet a) is to be transmitted by the network device or b) is to be discarded by the network device; and
in response to determining, based at least in part on the application of the access control policy indicated by the one or more modified fields of the header, that the packet is to be transmitted by the network device and not to be discarded by the network device:
retrieving, with the network device, the at least the payload of the packet from the packet memory,
generating, with the network device, a transmit packet at least by combining the at least the payload of the packet with the modified header, and
transmitting the transmit packet via the determined at least one egress port of the network device.

2. The method of claim 1 , further comprising, after generating the modified header, storing, with the packet processor, the modified header in the packet memory.

3. The method of claim 2 , wherein:
storing the at least the payload of the packet in the packet memory comprises storing the at least the payload of the packet at a first memory location in the packet memory, and
storing the modified header in the packet memory comprises storing the modified header at a second memory location, separate from the first memory location, in the packet memory.

4. The method of claim 3 , wherein:
processing the packet comprises processing the packet using a packet descriptor associated with the packet, and
the method further comprises, after processing the packet using the packet descriptor,
generating an egress packet descriptor corresponding to the packet, the egress packet descriptor being smaller than the packet descriptor used for processing of the packet, and
in response to determining that the packet is to be transmitted from the network device, enqueueing the egress packet descriptor in an egress queue for subsequent transmission of the transmit packet via the determined at least one egress port.

5. The method of claim 4 , wherein generating the egress packet descriptor comprises generating the egress packet descriptor to include at least memory location information, the memory location information indicating i) the first memory location at which the at least the payload of the packet is stored in the memory and ii) the second memory location at which the modified header is stored in the packet memory.

6. The method of claim 5 , wherein:
the method further comprises, when the egress packet descriptor is dequeued from the egress queue, retrieving, based on the memory location information in the egress packet descriptor, the at least the payload of the packet from the first memory location in the packet memory and the modified header from the second memory location in the packet memory, and
generating the transmit packet includes combining the at least the payload of the packet retrieved from the first memory location in the packet memory with the modified header retrieved from the second memory location in the packet memory.

7. The method of claim 5 , further comprising, i) in response to determining that the packet is to be transmitted from the network device and ii) prior to retrieving the at least the payload of the packet from the packet memory, triggering mirroring of the packet, the mirroring including
generating, with the packet processor, a copy of the egress packet descriptor, and
enqueuing the copy of the egress packet descriptor in an additional egress queue for mirroring of the packet to a destination other than the determined at least one egress port.

8. The method of claim 7 , further comprising, when the copy of the egress packet descriptor is dequeued from the additional egress queue,
retrieving, based on the memory location information in the copy of the egress packet descriptor, the at least the payload of the packet from the first memory location in the packet memory and the modified header from the second memory location in the packet memory,
generating a mirrored packet at least by combining the at least the payload of the payload retrieved, based on the memory location information in the copy of the egress packet descriptor, from the first memory location in the packet memory and the modified header retrieved, based on the memory location information in the copy of the egress packet descriptor, from the second memory location in the packet memory, and
transmitting the mirrored packet to the destination other than the determined at least one egress port.

9. The method of claim 1 , further comprising, in response to determining that the packet is to be discarded by the network device, i) discarding the packet at the network device and ii) not triggering mirroring of the packet by the network device.

10. The method of claim 1 , further comprising performing, based at least in part on the modified header, egress classification of the packet, wherein determining whether the packet a) is to be transmitted by the network device or b) is to be discarded by the network device is performed as part of the egress classification of the packet.

11. A network device, comprising:
a receive processor configured to
receive a packet from a network, and
store at least a payload of the packet in a packet memory;

a packet processor configured to process the packet, the packet processor being configured to at least i) determine at least one egress port via which the packet is to be transmitted by the network device, ii) modifying one or more fields in a header of the packet to generate a modified header that is indicative of an access control policy applying to the packet, and iii) determining, based at least in part on application of the access control policy indicated by the one or more modified fields of the header, whether the packet a) is to be transmitted by the network device or b) is to be discarded by the network device; and
a transmit processor configured to, in response to the determination, made by the packet processor based at least in part on the application of the access control policy indicated by the one or more modified fields of the header, that the packet is to be transmitted by the network device and not to be discarded by the network device,
retrieve the at least the payload of the packet from the packet memory,
generate a transmit packet at least by combining the at least the payload of the packet with the modified header, and
transmit the transmit packet via the determined at least one egress port of the network device.

12. The network device of claim 11 , wherein the packet processor is further configured to, after generating the modified header, store the modified header in the packet memory.

13. The network device of claim 12 , wherein the packet processor is configured to:
store the at least the payload of the packet at a first memory location in the packet memory, and
store the modified header at a second memory

Assignees

• Marvell Israel Misl Ltd

Inventors

• Melman David
• Mayer-Wolf Ilan
• Arad Carmi
• Zemach Rami

Classifications

• H04L69/22 Primary

  Parsing or analysis of headers · CPC title

• H04L49/9084 Primary

  Reactions to storage capacity overflow · CPC title

• H04L47/32

  by discarding or delaying data units, e.g. packets or frames · CPC title

• H04L47/2441

  relying on flow classification, e.g. using integrated services [IntServ] · CPC title