Document how to add table entries to P4 DPDK using its native control plane API

[jafingerhut]

Building P4 DPDK, compiling a program for it using p4c-dpdk, and loading it into the P4 DPDK data plane has a repo documenting the steps here: https://github.com/Yi-Tseng/p4-dpdk-target-notes

Perhaps it is also documented how to add/modify/remove table entries into the data plane from a control program, but if so, I have not found it yet. Making an example of that would be useful.

If this were documented, it could help enable running automated CI tests on the P4 DPDK data plane in the https://github.com/p4lang/p4c repo, thus significantly improving test coverage of the P4 DPDK data plane, and p4c-dpdk compiler back end.

[jafingerhut]

Note: I have instructions here: https://github.com/jafingerhut/p4-guide/tree/master/ipdk

on how to install software called IPDK (Infrastructure Programmer Development Kit) that includes a P4Runtime API server with the P4 DPDK data plane, and for many kinds of table entries you can add/modify/remove them via a control program using the P4Runtime API protocol, similar to what you can do with simple_switch_grpc.

However, the last version of IPDK that I have been able to build from open source components was released in 2023-Jul, and as far as I can tell only the Intel IPU-specific version of IPDK has later versions released, not the purely open source part that interoperates with the P4 DPDK data plane. I would be happy if someone could demonstrate how to build more recent versions of IPDK released later than 2023-Jul that work with the P4 DPDK data plane.

Note: The instructions at the link above may say version 24.01 (from 2024-Jan) in them, but as far as I can tell that version still installs version 23.07 (from 2023-Jul) of most of the software.