Merge branch 'bpf-xfrm-states'

Eyal Birger says:

====================
This patchset adds support for fetching XFRM state information from
an eBPF program called from TC.

The first patch introduces a helper for fetching an XFRM state from the
skb's secpath. The XFRM state is modeled using a new virtual struct which
contains the SPI, peer address, and reqid values of the state; This struct
can be extended in the future to provide additional state information.

The second patch adds a test example in test_tunnel_bpf.sh. The sample
validates the correct extraction of state information by the eBPF program.

v3:
  - Kept SPI and peer IPv4 address in state in network byte order
    following suggestion from Alexei Starovoitov
v2:
  - Fixed two comments by Daniel Borkmann:
    - disallow reserved flags in helper call
    - avoid compiling in helper code when CONFIG_XFRM is off
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>