mrgaoxx/tutorials

P4 language tutorials

P4 Tutorial

If you are reading this while not attending a live P4 tutorial class, see below for links to information about recently given live classes.

Introduction

Welcome to the P4 Tutorial! We've prepared a set of exercises to help you get started with P4 programming, organized into several modules:

1. Introduction and Language Basics

• Basic Forwarding
• Basic Tunneling

2. P4Runtime and the Control Plane

• P4Runtime

3. Monitoring and Debugging

• Explicit Congestion Notification
• Multi-Hop Route Inspection

4. Advanced Behavior

• Source Routing
• Calculator
• Load Balancing
• Quality of Service

5. Stateful Packet Processing

• Firewall
• Link Monitoring

Presentation

The slides are available online and in the P4_tutorial.pdf in the tutorial directory.

A P4 Cheat Sheet is also available online which contains various examples that you can refer to.

P4 Documentation

The documentation for P4_16 and P4Runtime is available here

All excercises in this repository use the v1model architecture, the documentation for which is available at:

1. The BMv2 Simple Switch target document accessible here talks mainly about the v1model architecture.
2. The include file v1model.p4 has extensive comments and can be accessed here.

Obtaining required software

If you are starting this tutorial at one of the proctored tutorial events, then we've already provided you with a virtual machine that has all of the required software installed. Ask an instructor for a USB stick with the VM image.

Otherwise, to complete the exercises, you will need to either build a virtual machine or install several dependencies.

To build the virtual machine:

• Install Vagrant and VirtualBox
• Clone the repository
• Before proceeding, ensure that your system has at least 25 Gbytes of free disk space, otherwise the installation can fail in unpredictable ways.
• cd vm-ubuntu-20.04
• vagrant up - This step typically takes over 1 hour to complete, and requires a reliable Internet connection throughout.
• When the machine reboots, you should have a graphical desktop machine with the required software pre-installed. There are two user accounts on the VM, vagrant (password vagrant) and p4 (password p4). The account p4 is the one you are expected to use.

Note: Before running the vagrant up command, make sure you have enabled virtualization in your environment; otherwise you may get a "VT-x is disabled in the BIOS for both all CPU modes" error. Check this for enabling it in virtualbox and/or BIOS for different system configurations.

You will need the script to execute to completion before you can see the p4 login on your virtual machine's GUI. In some cases, the vagrant up command brings up only the default vagrant login with the password vagrant. Dependencies may or may not have been installed for you to proceed with running P4 programs. Please refer the existing issues to help fix your problem or create a new one if your specific problem isn't addressed there.

To install dependencies by hand, please reference the vm-ubuntu-20.04 installation scripts. They contain the dependencies, versions, and installation procedure. You should be able to run them directly on an Ubuntu 16.04 machine:

• sudo ./root-bootstrap.sh
• sudo ./user-bootstrap.sh

Older tutorials

Multiple live tutorial classes have been given using the example code in this repository for hands-on exercises. For example, there is one each April or May at the P4 workshop at Stanford University in California, and there have been several at networking conferences such as ACM SIGCOMM.

Please create an issue for this tutorials repository if you know a public link for classroom video recordings and/or pre-built VM images that currently do not have such a link.

ACM SIGCOMM August 2019 Tutorial on Programming the Network Data Plane

https://p4.org/events/2019-08-23-p4-tutorial/

The page linked above has a link to download a pre-built VM image used for this class, as well as instructions to build one yourself from a particular branch of this repository.

P4 Developer Day, April 2019

https://p4.org/events/2019-04-30-p4-developer-day/

Both a beginner and advanced class were taught at this event. The page linked above contains instructions to download and install a pre-built Linux VM that was used during the classes.

P4 Developer Day, November 2017

• YouTube videos
  • This link plays the first welcome video of a series of 6 videos of tutorials given at this event.