Merge branch 'bpf_fanout'

Willem de Bruijn says:

====================
packet: add cBPF and eBPF fanout modes

Allow programmable fanout modes. Support both classical BPF programs
passed directly and extended BPF programs passed by file descriptor.

One use case is packet steering by deep packet inspection, for
instance for packet steering by application layer header fields.

Separate the configuration of the fanout mode and the configuration
of the program, to allow dynamic updates to the latter at runtime.

Changes
  v1 -> v2:
    - follow SO_LOCK_FILTER semantics on filter updates
    - only accept eBPF programs of type BPF_PROG_TYPE_SOCKET_FILTER
    - rename PACKET_FANOUT_BPF to PACKET_FANOUT_CBPF to match
      man 2 bpf usage: "classic" vs. "extended" BPF.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>