Merge branch 'bpf-prog-testing-framework'

Alexei Starovoitov says:

====================
bpf: program testing framework

Development and testing of networking bpf programs is quite cumbersome.
Especially tricky are XDP programs that attach to real netdevices and
program development feels like working on the car engine while
the car is in motion.
Another problem is ongoing changes to upstream llvm core
that can introduce an optimization that verifier will not
recognize. llvm bpf backend tests have no ability to run the programs.
To improve this situation introduce BPF_PROG_TEST_RUN command
to test and performance benchmark bpf programs.
It achieves several goals:
- development of xdp and skb based bpf programs can be done
in a canned environment with unit tests
- program performance optimizations can be benchmarked outside of
networking core (without driver and skb costs)
- continuous testing of upstream changes is finally practical

Patches 4,5,6 add C based test cases of various complexity
to cover some sched_cls and xdp features. More tests will
be added in the future. The tests were run on centos7 only.

For now the framework supports only skb and xdp programs. In the future
it can be extended to socket_filter and tracing program types.

More details are in individual patches.

v1->v2:
- rename bpf_program_test_run->bpf_prog_test_run
- add missing #include <linux/bpf.h> since libbpf.h shouldn't depend
on prior includes
- reordered patches 3 and 4 to keep bisect clean
====================

Signed-off-by: David S. Miller <davem@davemloft.net>