ONOS Fabric Pipeconf for Tofino

This repository contains instructions and scripts to compile and use fabric.p4 on Intel/Barefoot Tofino-enabled switches.

fabric.p4 is a P4 program distributed as part of ONOS, designed to work with Trellis, a set of SDN applications running on top of ONOS to provide the control plane for an IP fabric based on MPLS segment-routing.

To use ONOS to control a Tofino-enabled switch, you will need to run the Stratum agent on the switch.

Requirements

• Barefoot SDE = 9.0.0 (with the P4_16 compiler for Tofino)
• ONOS >= 2.2.1
• Docker (to run the build scripts without worrying about dependencies)
• cURL (to interact with the ONOS REST APIs)

Steps to build Tofino-enabled fabric.p4 pipeconfs

ONOS uses "pipeconfs" to deploy and manage a given P4 program on a device. Pipeconfs are distrubuted as ONOS applications, hence using the .oar packaging. The following steps provide instructions on how to generate an oar package that includes a compiled version of fabric.p4 that works on Tofino.

• src/main/java: contains Java code that implements the ONOS app responsible for registering the Tofino-enabled pipeconfs in ONOS;
• src/main/p4: contains code to compile fabric.p4 for Tofino.

To learn more about pipeconfs and how ONOS supports P4-programmable devices: https://github.com/opennetworkinglab/ngsdn-tutorial

1 - Obtain fabric.p4 sources from ONOS

fabric.p4 is distributed as part of ONOS. We recommend using the onos-2.2 branch, which is an LTS branch.

git clone -b onos-2.2 https://github.com/opennetworkinglab/onos

Set the ONOS_ROOT env variable to the location where ONOS was cloned:

export ONOS_ROOT=$PWD/onos

2 - Build Tofino-enabled fabric pipeconf

To build fabric.p4 using the Barefoot compiler and to create the pipeconf .oar package:

cd fabric-tofino # this repo
make build PROFILES=all

Fabric profiles

The above command will build the fabric.p4 profiles specified in the PROFILES argument. Possible values are:

Check the Makefile for other profiles.

To build all profiles: PROFILES=all.

To build a subset of the available profiles: PROFILES="fabric fabric-bng"

The P4 compiler outputs to include in the .oar package (such as tofino.bin, context.json, and p4info.txt) will be placed under src/main/resources/p4c-out.

When done, the pipeconf .oar package can be found in target/fabric-tofino-<VERSION>.oar

Using containerized version of the Barefoot SDE / p4c compilers

The previous command expects the bf-p4c compiler to be installed locally. As an alternative, the build script supports using a Docker-based distribution of the Barefoot SDE / p4c compilers. To do so, simply set the SDE_DOCKER_IMG make argument (or environment variable) to a Docker image that can be downloaded via docker pull, for example:

make build SDE_DOCKER_IMG=my-docker-repo/bf-sde:9.0.0 PROFILES=all

The build script will use docker run to invoke the bf-p4c command inside the given image. For this reason, the script expects a Docker image that has the whole Barefoot SDE installed in it or just the p4c package. In both cases, the bf-p4c executable should be on PATH. We do not provide such image, but one can be easily generated by executing the SDE install instructions inside a Dockerfile.

Steps to use the Tofino-enabled fabric pipeconf with ONOS

1 - Get and run ONOS

The minimum required ONOS version that works with this pipeconf is 2.2.1.

You can either build from sources (using the onos-2.2 or master branch), or run one the released versions: https://wiki.onosproject.org/display/ONOS/Downloads

Pre-built ONOS Docker images are available here: https://hub.docker.com/r/onosproject/onos/tags

For more information on how to get and run ONOS: https://wiki.onosproject.org/display/ONOS/Guides

2 - Start Stratum on your switch

For instructions on how to install and run Stratum on Tofino-enabled switches: https://github.com/stratum/stratum/tree/master/stratum/hal/bin/barefoot

3 - Install pipeconf app in ONOS

To install the pipeconf app built in the previous step, assuming ONOS is running on the local machine:

make pipeconf-install ONOS_HOST=localhost

Use the ONOS_HOST argument to specify the hostname/IP address of the machine where ONOS is running.

This command is a wrapper to a curl command that uses the ONOS REST API to upload and activate the .oar package previously built.

You should see the ONOS log updating with messages notifying the registration of new Tofino-specific pipeconfs in the system, depending on the fabric.p4 profiles compiled before and the Barefoot SDE/p4c version used:

New pipeconf registered: org.opencord.fabric.tofino.mavericks_sde_9_0_0 (fingerprint=...)
New pipeconf registered: org.opencord.fabric.tofino.montara_sde_9_0_0 (fingerprint=...)
New pipeconf registered: org.opencord.fabric-bng.tofino.mavericks_sde_9_0_0 (fingerprint=...)
New pipeconf registered: org.opencord.fabric-bng.tofino.montara_sde_9_0_0 (fingerprint=...)
...

NOTE: it might take up to one minute for the pipeconfs to be registered. This is currently a bug and will be fixed soon.

To check all pipeconfs registered in the system, use the ONOS CLI:

onos> pipeconfs

4 - Connect ONOS to a Stratum switch

Activate the Barefoot drivers in ONOS:

onos> app activate org.onosproject.drivers.barefoot

This command will register a new driver named stratum-tofino. As the name suggests, this driver allows ONOS to control Tofino-enabled Stratum switches.

For ONOS to be able to discover your switch, you need to push a JSON file, usually referred to as the "netcfg" file. We provide an example of such tofino-netcfg.json file in this repository. Make sure to modify the following values:

• managementAddress is expected to contain a valid URI with host and port of the Stratum gRPC server running on the switch;
• The device_id URI query parameter is the P4Runtime-internal device_id, also known as the Stratum "Node ID". Usually, you can leave this value set to 1;
• Use the pipeconf field to specify which pipeconf/fabric profile to deploy on the switch.

Push the tofino-netcfg.json to ONOS using the command:

make netcfg ONOS_HOST=localhost

Like before, this command is a wrapper to a curl command that uses the ONOS REST API to push the tofino-netcfg.json file.

Check the ONOS log for potential errors.

Using Trellis with Stratum+Tofino switches

Check the official Trellis documentation here: https://docs.trellisfabric.org

In the "Device Configuration" section: https://docs.trellisfabric.org/configuration/device-config.html

make sure to replace the basic JSON node for OpenFlow devices with the one provided in tofino-netcfg.json, for example:

{
  "devices" : {
    "device:leaf-1" : {
      "segmentrouting" : {
        "ipv4NodeSid" : 101,
        "ipv4Loopback" : "192.168.0.201",
        "ipv6NodeSid" : 111,
        "ipv6Loopback" : "2000::c0a8:0201",
        "routerMac" : "00:00:00:00:02:01",
        "isEdgeRouter" : true,
        "adjacencySids" : []
      },
      "basic": {
        "managementAddress": "grpc://10.0.0.1:28000?device_id=1",
        "driver": "stratum-tofino",
        "pipeconf": "org.opencord.fabric.tofino.montara_sde_9_0_0"
      }
    }
  }
}

Support

To report issues when compiling fabric.p4 for Tofino (i.e., compiler errors), please contact Intel/Barefoot support.

To get help with ONOS and the fabric pipeconf, please contact brigade-p4@onosproject.org (this is a public mailing list, please beware of not discussing information under Intel/Barefoot NDA)