[PATCH v3] tap: fix build of TAP BPF program

[Stephen Hemminger]

On Thu, 20 Jul 2023 16:25:49 -0700
Stephen Hemminger <stephen at networkplumber.org> wrote:

> Move the BPF program related code into a subdirectory.
> And add a Makefile for building it.
> 
> The code was depending on old versions of headers from iproute2.
> Include those headers here so that build works.
> 
> The standalone build was also broken because by
> commit ef5baf3486e0 ("replace packed attributes")
> which introduced __rte_packed into this code.
> 
> Add a python program to extract the resulting BPF into
> a format that can be consumed by the TAP driver.
> 
> Update the documentation.
> 
> Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>

Note: there are a couple of bogus checkpatch warnings from this.
The tap_bpf_program is not a regular DPDK library so it doesn't use
the DPDK macros. And the bpf_api.h and bpf_elf.h are from iproute2
upstream and won't conform to DPDK checkpatch requirements.