[PATCH bpf 0/5] flow_dissector: lay groundwork for calling BPF hook from eth_get_headlen

[Stanislav Fomichev <sdf@google.com>]

This patch series fixes the existing BPF flow dissector API to
support calling BPF progs from the eth_get_headlen context (the support
itself will be added in bpf-next tree).

The summary of the changes:
  * fix VLAN handling in bpf_flow.c, we don't need to peek back and look
    at skb->vlan_present; add selftests
  * pass and use flow_keys->n_proto instead of skb->protocol
  * fix clamping of flow_keys->nhoff for packets with nhoff > 0
  * prohibit access to most of the __sk_buff fields from BPF flow
    dissector progs; only data/data_end/flow_keys are allowed (all input
    is now passed via flow_keys)
  * finally, document BPF flow dissector program environment

Stanislav Fomichev (5):
  selftests/bpf: fix vlan handling in flow dissector program
  net/flow_dissector: pass flow_keys->n_proto to BPF programs
  flow_dissector: fix clamping of BPF flow_keys for non-zero nhoff
  flow_dissector: allow access only to a subset of __sk_buff fields
  flow_dissector: document BPF flow dissector environment

 .../networking/bpf_flow_dissector.txt         | 115 ++++++++++++++++++
 net/core/filter.c                             |  16 +--
 net/core/flow_dissector.c                     |   4 +-
 .../selftests/bpf/prog_tests/flow_dissector.c |  68 +++++++++++
 tools/testing/selftests/bpf/progs/bpf_flow.c  |  19 ++-
 5 files changed, 196 insertions(+), 26 deletions(-)
 create mode 100644 Documentation/networking/bpf_flow_dissector.txt

-- 
2.21.0.392.gf8f6787159e-goog