README.md

P4Runtime PTF tests for ONOS fabric.p4

Dependencies (on the test machine)

• ptf
• scapy with extensions
• P4Runtime: the protobuf / gRPC Python code for P4Runtime must have been generated and installed in the Python path.
• BMv2
• ONOS: for fabric.p4 code and pre-compiled artifacts (no need to build ONOS, simply clone the repo)
• Set ONOS_ROOT env variable to the location where you cloned the ONOS repo

Before running the tests

Fabric profiles

fabric.p4 is available in different profiles. Each profile provides different forwarding capabilities and is determined by the preprocessor flags used to compile fabric.p4.

The available profiles are:

Profile name	p4c preprocessor flags	Description
fabric	None	Basic fabric profile
fabric-spgw	-DWITH_SPGW	With SPGW user plane functionality
fabric-int	-DWITH_INT_SOURCE -DWITH_INT_TRANSIT	With INT (spec v0.5) source and transit functionality
fabric-spgw-int	-DWITH_SPGW -DWITH_INT_SOURCE -DWITH_INT_TRANSIT	With both SPGW and INT functionalities

Compiling fabric.p4 for BMv2

If running tests on BMv2, you can use the pre-compiled artifacts (BMv2 JSON and P4Info) distributed with ONOS. These files are located under:

$ONOS_ROOT/pipelines/fabric/impl/src/main/resources/p4c-out

If you need to make changes to fabric.p4, you can recompile the P4 program using the following commands:

cd $ONOS_ROOT/pipelines/fabric/impl/src/main/resources
make

The make command will build all profiles. To build only a specific profile:

make <profile-name>

Compile for other targets

Compile fabric.p4 with the desired backend and preprocessor flags. For example, to compile for Tofino:

cd $ONOS_ROOT/pipelines/fabric/impl/src/main/resources/
p4c --target tofino --arch v1model -DWITH_SPGW -o fabric-spgw.out \
    --p4runtime-format text --p4runtime-file fabric-spgw.out/p4info.proto \
    fabric.p4 

Steps to run the tests with BMv2

1. Setup veth interfaces, using the script provided with BMv2. This script should be executed only once before executing any PTF test, or after a reboot of the test machine.

   cd <path to bmv2 repo>/tools
   sudo ./veth_setup.sh
   

If using the ONOS-P4 Dev VM, the veth_setup.sh script will be located under /home/sdn.

2. Run the PTF tests using a convenient make command:

   cd fabric-p4test/tests/ptf
   make
   

   The make command will execute tests for all fabric profiles. To run tests for only a specific profile:

   make <profile-name>
   

   Alternatively, you can run the ptf-runner.py script with BMv2 arguments. For example, to run tests for the fabric profile:

   sudo ./ptf_runner.py --device bmv2 \
       --p4info ${ONOS_ROOT}/pipelines/fabric/impl/src/main/resources/p4c-out/fabric/bmv2/default/p4info.txt \
       --bmv2-json ${ONOS_ROOT}/pipelines/fabric/impl/src/main/resources/p4c-out/fabric/bmv2/default/bmv2.json \
       --ptf-dir fabric.ptf --port-map port_map.veth.json \
       all ^spgw
   

Steps to run the tests with Tofino

1. Start bf_switchd (with --skip-p4) as you normally do.

2. Run ptf_runner.py with Tofino arguments and --skip-test:

   sudo ./ptf_runner.py --device tofino \ 
       --p4info p4info.txt \
       --tofino-bin tofino.bin \
       --tofino-ctx-json context.json \
       --ptf-dir fabric.ptf --port-map port_map.veth.json \
       --skip-test
   

   This will configure the pipeline on the switch, but will not execute the tests.

3. Configure switch ports using bf_switchd CLI.

4. Execute tests by running ptf_runner.py with --skip-config (since the pipeline is already configured):

   sudo ./ptf_runner.py --device tofino \ 
       --p4info p4info.txt \
       --tofino-bin tofino.bin \
       --tofino-ctx-json context.json \
       --ptf-dir fabric.ptf --port-map port_map.veth.json \
       --skip-config all ^spgw
   

Running the right PTF tests for the right profile

Based on which preprocessor flags you are using to compile fabric.p4 (i.e. which fabric.p4 profile you are trying to use), some PTF tests will not be available. For example, you will only be able to run the SPGW tests successfully if fabric.p4 was compiled with -DWITH_SPGW. We have tagged the fabric PTF tests to enable you to choose which ones to run based on the fabric.p4 profile you are using. You simply need to provide the appropriate PTF "test specs" at the end of the ptf_runner.py command-line invocation based on your preprocessor flags as per this table:

Profile	PTF test specs
fabric	all ^spgw ^int
fabric-spgw	all ^int
fabric-int	all ^spgw
fabric-spgw-int	all

For an example of how PTF test specs are used, you can refer to this Makefile used for BMv2 tests.

Port map JSON file

This file is required to let PTF know which test interface corresponds to which P4 dataplane port number. Consider the following test topology:

             ASIC under test
******************************************
148          149          134          135
 |            |            |            |
 |            |            |            |
 |            |            |            |
ens2f0       ens2f1       ens2f2       ens2f3
******************************************
              PTF test server

For this topology one may use the following port map JSON file:

[
    {
        "ptf_port": 0,
        "p4_port": 148,
        "iface_name": "ens2f0"
    },
    {
        "ptf_port": 1,
        "p4_port": 149,
        "iface_name": "ens2f1"
    },
    {
        "ptf_port": 2,
        "p4_port": 134,
        "iface_name": "ens2f2"
    },
    {
        "ptf_port": 3,
        "p4_port": 135,
        "iface_name": "ens2f3"
    }
]

The "ptf_port" is the id used to reference the port in the Python PTF tests. As of now, "ptf_port" must be equal to the index of the entry in the port map JSON array of interfaces. Port numbers must never be used directly when calling PTF Python functions (e.g. send_packet); instead, when writing your own tests, call the swports method which will map the "ptf_port" to the "p4_port" based on the provided port map JSON file.