BMv2 PNA Support

BMv2 PNA Support

This page uses Raw links from GitHub

Contributor: Rupesh Chiluka (@rupesh-chiluka-marvell)

Mentors: Bili Dong (@qobilidop), Hari Thantry (@thantry)

Table of Contents

• BMv2 PNA Support
  • Table of Contents
  • Abstract
  • Goals
  • Results
  • Implementation details
    • New PNA NIC target in BMv2
    • P4C backend for the new BMv2 PNA NIC target
  • Demo
  • Future Work
    • Standard PNA Features (Implemented)
    • Standard PNA Features (Yet to be Implemented)
    • Experimental PNA Features (Yet to be Implemented)

Abstract

As the P4 use cases on the NIC side increase, so does the need for a P4 simulator that supports Portable NIC Architecture (PNA). Currently, the BMv2 simulator only supports the v1model and Portable Switch Architecture (PSA) specifications. This project aims to integrate a minimal core subset of the PNA into the BMv2 and the P4C. The PNA Architecture Block Diagram is shown in below:

Goals

• Create a new target in BMv2 supporting the core subset of PNA
• Create a new P4C backend for the new BMv2’s PNA NIC target
• Design test cases to ensure the PNA NIC target is working

Results

The project successfully creates a new target in BMv2 to support PNA and a corresponding backend in P4C. A test case is implemented to ensure the new PNA NIC target can forward the packets between interfaces.

Implementation details

New PNA NIC target in BMv2

Relevant PRs:

• https://github.com/p4lang/behavioral-model/pull/1255
• https://github.com/p4lang/behavioral-model/pull/1262
• https://github.com/p4lang/behavioral-model/pull/1263
• https://github.com/p4lang/behavioral-model/pull/1265

Created a basic PNA NIC target with basic externs (Meter, Counter, Register, etc). A test case was added to check whether the new PNA NIC could load the P4C-generated PNA JSON file. Makefiles are adjusted to build the new PNA NIC target while building the bmv2 repository. Just follow the build commands mentioned in the repository.

Resultant Binary: pna_nic

P4C backend for the new BMv2 PNA NIC target

Relevant PR: https://github.com/p4lang/p4c/pull/4729

Created a new p4c backend for the PNA NIC target.

Since both PSA_SWITCH and PNA_NIC compiler backends have a lot of common code, I created a common code base and called it “portable_common.” The PSA and PNA components will now inherit from the “portable” components.

Merged the ProgramStrucutre and CodeGenerator classes into one class.

Included the PNA specification file from p4lang/pna/pna.p4.

Makefiles are adjusted to build the new P4C backend for the PNA NIC target while building the P4C repository. Just follow the build commands mentioned in the repository.

Resultant Binary: p4c-bm2-pna

Demo

• Created a similar virtual interface setup as mentioned in this tutorial.

• The pna-demo-L2-one-table.p4 program from p4lang/pna repository is used to test the new PNA NIC target.

• Compile pna-demo-L2-one-table.p4 using p4c-bm2-pna binary.
  • p4c-bm2-pna pna-demo-L2-one-table.p4 -o pna-demo-L2-one-table.json
• To start the pna_nic target:

• start the pna_nic_CLI and populate the L2_fwd table mentioned in the P4 program using the below example (or your own) data:
  • table_add L2_fwd L2_send_to_port ba:dd:b1:f5:03:3c => 0
  • table_add L2_fwd L2_send_to_port be:05:e2:d2:4a:bc => 1
  • table_add L2_fwd L2_send_to_port 52:04:da:9b:15:59 => 2

• Send the Packets from one interface and listen on another interface. Example:

Now raw = true

Future Work

This project integrates a minimal core subset of the PNA into BMv2 and P4C. Many PNA use cases have yet to be implemented in the BMv2.

Standard PNA Features (Implemented)

• Basic Forwarding
• Counters
• Meters
• Hash
• Internet Checksum
• Random

Standard PNA Features (Yet to be Implemented)

• Recirculation
• Dropping
• Differentiate between Host and Network Interfaces

Experimental PNA Features (Yet to be Implemented)

• IPSec Encrypt/Decrypt
• Large Receive Offload (LRO)
• Receive Side Scaling (RSS)
• TCP segmentation offloading (TSO)