Barefoot Networks Software Development Environment (c) Barefoot Networks Inc, 2019-present

Table of contents

1. Summary
2. Compiling
3. Testing
4. Examples Table
5. Troubleshooting

1. Summary

• P4 version: P4_16
• Architectures: Tofino Native Architecture (TNA), Tofino2 Native Architecture (T2NA)
• Programming stack: Barefoot Runtime Interface (BRI)
• Purpose: Demonstrate the usage of TNA and T2NA features and verify the P4 Studio SDE installation

The examples demonstrate how to use selected features of TNA and T2NA. Furthermore, the example programs serve as a test vehicle to verify that that the Barefoot P4 Studio SDE environment has been properly installed and configured to enable running packet tests (PTF) against the Tofino ASIC model for the P4-16 software stack.

The examples in this directory are tested and verified to be functional. Each directory is self-contained -- it contains a readme file, the p4 file(s), and the PTF tests associated with the example. The P4 file with the same name as the directory (with a .p4 extension) is typically the main P4 file. Each example's readme file contains a description of what it does and special instructions on how to build or run the example, if any.

Most examples are tested on both, TNA and T2NA. Each example's readme file lists the architectures it is tested on.

Please check the corresponding readme file of an example before running it.

2. Compiling

All examples are automatically built and installed by default during the P4 Studio installation process. If needed, they can be built and installed through the P4 Studio Build tool. The following instructions are needed only when an existing example was modified, or a new example was added. To run an example included and built with P4 Studio, the please continue with Section 3.

An example program can be compiled by using the provided build scripts by using the instructions below if nothing different is stated in its readme file:

export SDE=/path/to/sde/
export SDE_INSTALL=$SDE/install
export PATH=$SDE_INSTALL/bin:$PATH
cd $SDE/pkgsrc/p4-build
./autogen.sh
cd $SDE/build/p4-examples

For Tofino:

$SDE/pkgsrc/p4-build/configure --with-tofino --with-p4c=p4c --prefix=$SDE_INSTALL \
      --bindir=$SDE_INSTALL/bin \
      P4_NAME=<program name> \
      P4_PATH=$SDE/pkgsrc/p4-examples/p4_16_programs/<program name>/<program name>.p4 \
      P4_VERSION=p4-16 P4_ARCHITECTURE=tna \
      LDFLAGS="-L$SDE_INSTALL/lib"

For Tofino2:

$SDE/pkgsrc/p4-build/configure --with-tofino2 --with-p4c=p4c --prefix=$SDE_INSTALL \
      --bindir=$SDE_INSTALL/bin \
      P4_NAME=<program name> \
      P4_PATH=$SDE/pkgsrc/p4-examples/p4_16_programs/<program name>/<program name>.p4 \
      P4_VERSION=p4-16 P4_ARCHITECTURE=t2na \
      LDFLAGS="-L$SDE_INSTALL/lib"

Then, for both Tofino and Tofino2:

make
make install

3. Testing

To run an example, follow these steps if nothing different is stated in its readme file:

export SDE=/path/to/sde/
export SDE_INSTALL=$SDE/install
sudo $SDE_INSTALL/bin/veth_setup.sh

In three separate terminal windows:

cd $SDE
./run_tofino_model.sh --arch <tofino|tofino2> -p <program name>

cd $SDE
./run_switchd.sh --arch <tofino|tofino2> -p <program name>

cd $SDE
./run_p4_tests.sh --arch <tofino|tofino2> -p <program name>

Example test output:

[...]
Setting up veth interfaces
No of Veths is 64
Adding CPU veth
Arch is tofino
Target is asic-model
Connecting to localhost port 7777 to check status on these devices: [0]
Waiting for device 0 to be ready
Started port clean script
WARNING: No route found for IPv6 destination :: (no default route?)
test.DynHashingTest ... Subscribe attempt #1
Subscribe response received 0
Binding with p4_name tna_dyn_hashing
Binding with p4_name tna_dyn_hashing successful!!
Received tna_dyn_hashing on GetForwarding
=============== Testing <test case> entry operation===============
<per test case details>
ok

  ----------------------------------------------------------------------
<summary of all testcases>

OK

4. Example List

The table provides an overview on the features demonstrated in the examples. For each major TNA/T2NA feature, the example demonstrating is usage is listed.

Feature	Example Name
Action profiles	tna_action_profile
Action selectors	tna_action_selector
Batch read error reporting	tna_lpm_match
Batch write error reporting	tna_ternary_match
BRI and hardware interaction	tna_operations
BRI and pdfixed over Thrift in one test	bri_with_pdfixed_thrift
Bridged metadata	tna_bridged_md
Checksum verification and update	tna_checksum
Configure ports	tna_ports
Counters	tna_counter
Custom hash	tna_custom_hash
Digest	tna_digest
Dynamic hash selection	tna_dyn_hashing
Dynamic key mask	tna_dkm
Dynamically set pipeline program	bri_set_forwarding_pipeline
Exact match	tna_exact_match
L2/L3 Switching	tna_simple_switch
Longest prefix match (algorithmic-lpm-based)	tna_lpm_match
Longest prefix match (TCAM-based)	tna_lpm_match
Low pass filter (LPF)	tna_meter_lpf_wred
Match-action table entry scopes	tna_exact_match
Meter byte counter adjustment	tna_meter_bytecount_adjust
Meters	tna_meter_lpf_wred
Mirror	tna_mirror
Multicast	tna_multicast
Multiple pipelines in one program	tna_32q_2pipe
Multiple programs on one device	tna_32q_multiprogram
P4Runtime basic example	p4rt_utests
P4Runtime comprehensive example	onf_fabric
Packet generator	tna_pktgen
Parser value sets (PVS)	tna_pvs
Pipeline snapshots	tna_snapshot
Port metadata	tna_port_metadata
Port metadata using an extern	tna_port_metadata_extern
Proxy hash	tna_proxy_hash
Random	tna_random
Range Match	tna_range_match
Register table entry scopes	tna_register
Registers and register actions	tna_register
Resubmit	tna_resubmit
Symmetric Hash	tna_symmetric_hash
Table default entry handling	tna_exact_match
Table entry idle timeout	tna_idletimeout
Table key field slicing	tna_field_slice
Table pipe scope handling	tna_exact_match
Ternary match (algorithmic-TCAM-based)	tna_ternary_match
Ternary match (TCAM-based)	tna_ternary_match
Timestamps	tna_timestamp
WRED	tna_meter_lpf_wred

5. Troubleshooting

Please contact [email protected] for issues related to this program. To quickly resolve your issue, please include with your issue report:

1. The P4 program and PTF test you exercised.
2. The P4 Studio SDE version.
3. The OS, Virtual Machine, or Container environment you are using.
4. The steps followed to exercise the test.
5. A description of the error encountered and/or unexpected behavior and any relevant execution artifacts, e.g. a console log with an error message, a driver log, and/or compiler output artifacts.

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