Daniel, BPF list,

Over the last week or so David Ahern and I worked on a patchset that solves
the problem discussed here along with a self-test.

Attached here is a patchset of 3 files which covers the following:

[PATCH 1/3] bpf: Add support for mark with bpf_fib_lookup
[PATCH 2/3] tools: Update bpf header
[PATCH 3/3] selftests: Add selftests for fwmark support in bpf_fib_lookup

I have tested those against a very recent clone of the latest 5.13-rc7.
Self-test results look like this:

----
# ./test_bpf_fib_lookup.sh
[test_bpf_fib_lookup.sh] START
- Running test_egress_ipv4_fwmark
  * mark 0: PASS
  * mark 2: PASS
- Running test_egress_ipv6_fwmark
  * mark 0: PASS
  * mark 2: PASS
[test_bpf_fib_lookup.sh] PASS: 4 -- FAIL: 0
# echo $?
0
----

Let me know what you think and if there's anything else needed to incorporate
the patchset into the kernel as well as what you think the next steps should be.

Regards,
Rumen Telbizov