Merge branch 'bpf: net: Remove duplicated code from bpf_setsockopt()'

Merge branch 'bpf: net: Remove duplicated code from bpf_setsockopt()'

Martin KaFai Lau says:

====================

The code in bpf_setsockopt() is mostly a copy-and-paste from
the sock_setsockopt(), do_tcp_setsockopt(), do_ipv6_setsockopt(),
and do_ip_setsockopt().  As the allowed optnames in bpf_setsockopt()
grows, so are the duplicated code.  The code between the copies
also slowly drifted.

This set is an effort to clean this up and reuse the existing
{sock,do_tcp,do_ipv6,do_ip}_setsockopt() as much as possible.

After the clean up, this set also adds a few allowed optnames
that we need to the bpf_setsockopt().

The initial attempt was to clean up both bpf_setsockopt() and
bpf_getsockopt() together.  However, the patch set was getting
too long.  It is beneficial to leave the bpf_getsockopt()
out for another patch set.  Thus, this set is focusing
on the bpf_setsockopt().

v4:
- This set now depends on the commit f574f7f839fc ("net: bpf: Use the protocol's set_rcvlowat behavior if there is one")
  in the net-next tree.  The commit calls a specific protocol's
  set_rcvlowat and it changed the bpf_setsockopt
  which this set has also changed.

  Because of this, patch 9 of this set has also adjusted
  and a 'sock' NULL check is added to the sk_setsockopt()
  because some of the bpf hooks have a NULL sk->sk_socket.
  This removes more dup code from the bpf_setsockopt() side.
- Avoid mentioning specific prog types in the comment of
  the has_current_bpf_ctx(). (Andrii)
- Replace signed with unsigned int bitfield in the
  patch 15 selftest. (Daniel)

v3:
- s/in_bpf/has_current_bpf_ctx/ (Andrii)
- Add comment to has_current_bpf_ctx() and sockopt_lock_sock()
  (Stanislav)
- Use vmlinux.h in selftest and add defines to bpf_tracing_net.h
  (Stanislav)
- Use bpf_getsockopt(SO_MARK) in selftest (Stanislav)
- Use BPF_CORE_READ_BITFIELD in selftest (Yonghong)

v2:
- A major change is to use in_bpf() to test if a setsockopt()
  is called by a bpf prog and use in_bpf() to skip capable
  check.  Suggested by Stanislav.
- Instead of passing is_locked through sockptr_t or through an extra
  argument to sk_setsockopt, v2 uses in_bpf() to skip the lock_sock()
  also because bpf prog has the lock acquired.
- No change to the current sockptr_t in this revision
- s/codes/code/
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>