tree a1b746996795ad8ca61eca7380b3bd43e6d750af
parent a010a2f6540ecc39f8701c6f7d35e22992c03fb6
author Daniel Borkmann <daniel@iogearbox.net> 1504914035 +0200
committer David S. Miller <davem@davemloft.net> 1504930389 -0700

bpf: make error reporting in bpf_warn_invalid_xdp_action more clear

Differ between illegal XDP action code and just driver
unsupported one to provide better feedback when we throw
a one-time warning here. Reason is that with 814abfabef3c
("xdp: add bpf_redirect helper function") not all drivers
support the new XDP return code yet and thus they will
fall into their 'default' case when checking for return
codes after program return, which then triggers a
bpf_warn_invalid_xdp_action() stating that the return
code is illegal, but from XDP perspective it's not.

I decided not to place something like a XDP_ACT_MAX define
into uapi i) given we don't have this either for all other
program types, ii) future action codes could have further
encoding there, which would render such define unsuitable
and we wouldn't be able to rip it out again, and iii) we
rarely add new action codes.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>