selftests/bpf: Check VLAN tag and proto in xdp_metadata

Verify, whether VLAN tag and proto are set correctly.

To simulate "stripped" VLAN tag on veth, send test packet from VLAN
interface.

Also, add TO_STR() macro for convenience.

Acked-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
Link: https://lore.kernel.org/r/20231205210847.28460-19-larysa.zaremba@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Make sure we trigger metadata kfuncs for dst 8080

xdp_metadata test is flaky sometimes:

verify_xsk_metadata:FAIL:rx_hash_type unexpected rx_hash_type: actual 8 != expected 0

Where 8 means XDP_RSS_TYPE_L4_ANY and is exported from veth driver only when
'skb->l4_hash' condition is met. This makes me think that the program is
triggering again for some other packet.

Let's have a filter, similar to xdp_hw_metadata, where we trigger XDP kfuncs
only for UDP packets destined to port 8080.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20231204174423.3460052-1-sdf@google.com

selftests/bpf: Adjust bpf_xdp_metadata_rx_hash for new arg

Update BPF selftests to use the new RSS type argument for kfunc
bpf_xdp_metadata_rx_hash.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/168132894068.340624.8914711185697163690.stgit@firesoul
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Verify xdp_metadata xdp->af_xdp path

- create new netns
- create veth pair (veTX+veRX)
- setup AF_XDP socket for both interfaces
- attach bpf to veRX
- send packet via veTX
- verify the packet has expected metadata at veRX

Cc: John Fastabend <john.fastabend@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Anatoly Burakov <anatoly.burakov@intel.com>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>
Cc: Magnus Karlsson <magnus.karlsson@gmail.com>
Cc: Maryam Tahhan <mtahhan@redhat.com>
Cc: xdp-hints@xdp-project.net
Cc: netdev@vger.kernel.org
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230119221536.3349901-12-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>