[bpf-next,v5,0/6] Follow-up BPF helper improvements

This series addresses most of the feedback [0] that was to be followed
up from the last series, that is, UAPI helper comment improvements and
getting rid of the ifindex obj file hacks in the selftest by using a
BPF map instead. The __sk_buff data/data_end pointer work, I'm planning
to do in a later round as well as the mem*() BPF improvements we have
in Cilium for libbpf. Next, the series adds two features, i) a helper
called redirect_peer() to improve latency on netns switch, and ii) to
allow map in map with dynamic inner array map sizes. Selftests for each
are added as well. For details, please check individual patches, thanks!

  [0] https://lore.kernel.org/bpf/cover.1601477936.git.daniel@iogearbox.net/

v4 -> v5:
  - Replace cnt == -EOPNOTSUPP check with cnt < 0; I've used < 0
    here as I think it's useful to keep the existing cnt == 0 ||
    cnt >= ARRAY_SIZE(insn_buf) for error detection (Andrii)
v3 -> v4:
  - Rename new array map flag to BPF_F_INNER_MAP (Alexei)
v2 -> v3:
  - Remove tab that slipped into uapi helper desc (Jakub)
  - Rework map in map for array to error from map_gen_lookup (Andrii)
v1 -> v2:
  - Fixed selftest comment wrt inner1/inner2 value (Yonghong)

Daniel Borkmann (6):
  bpf: improve bpf_redirect_neigh helper description
  bpf: add redirect_peer helper
  bpf: allow for map-in-map with dynamic inner array map entries
  bpf, selftests: add test for different array inner map size
  bpf, selftests: make redirect_neigh test more extensible
  bpf, selftests: add redirect_peer selftest

 drivers/net/veth.c                            |   9 +
 include/linux/bpf.h                           |   2 +-
 include/linux/netdevice.h                     |   4 +
 include/uapi/linux/bpf.h                      |  30 ++-
 kernel/bpf/arraymap.c                         |  17 +-
 kernel/bpf/hashtab.c                          |   6 +-
 kernel/bpf/verifier.c                         |   4 +-
 net/core/dev.c                                |  15 +-
 net/core/filter.c                             |  54 ++++-
 net/xdp/xskmap.c                              |   2 +-
 tools/include/uapi/linux/bpf.h                |  30 ++-
 .../selftests/bpf/prog_tests/btf_map_in_map.c |  39 +++-
 .../selftests/bpf/progs/test_btf_map_in_map.c |  43 ++++
 .../selftests/bpf/progs/test_tc_neigh.c       |  40 ++--
 .../selftests/bpf/progs/test_tc_peer.c        |  45 ++++
 tools/testing/selftests/bpf/test_tc_neigh.sh  | 168 ---------------
 .../testing/selftests/bpf/test_tc_redirect.sh | 204 ++++++++++++++++++
 17 files changed, 488 insertions(+), 224 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/progs/test_tc_peer.c
 delete mode 100755 tools/testing/selftests/bpf/test_tc_neigh.sh
 create mode 100755 tools/testing/selftests/bpf/test_tc_redirect.sh