[PATCH v2 bpf-next 0/7] Add __sk_buff->sk, bpf_tcp_sock, BPF_FUNC_tcp_sock and BPF_FUNC_sk_fullsock

[Martin KaFai Lau <kafai@fb.com>]

This series adds __sk_buff->sk, "struct bpf_tcp_sock",
BPF_FUNC_sk_fullsock and BPF_FUNC_tcp_sock.  Together, they provide
a common way to expose the members of "struct tcp_sock" and
"struct bpf_sock" for the bpf_prog to access.

The patch series first adds a bpf_sock pointer to __sk_buff
and a new helper BPF_FUNC_sk_fullsock.

It then adds BPF_FUNC_tcp_sock to get a bpf_tcp_sock
pointer from a bpf_sock pointer.

The current use case is to allow a cg_skb_bpf_prog to provide
per cgroup traffic policing/shaping.

Please see individual patch for details.

v2:
- Patch 1 depends on
  commit d623876646be ("bpf: Fix narrow load on a bpf_sock returned from sk_lookup()")
  in the bpf branch.
- Add sk_to_full_sk() to bpf_sk_fullsock() and bpf_tcp_sock()
  such that there is a way to access the listener's sk and tcp_sk
  when __sk_buff->sk is a request_sock.
  The comments in the uapi bpf.h is updated accordingly.
- bpf_ctx_range_till() is used in bpf_sock_common_is_valid_access()
  in patch 1.  Saved a few lines.
- Patch 2 is new in v2 and it adds "state", "dst_ip4", "dst_ip6" and
  "dst_port" to the bpf_sock.  Narrow load is allowed on them.
  The "state" (i.e. sk_state) has already been used in
  INET_DIAG (e.g. ss -t) and getsockopt(TCP_INFO).
- While at it in the new patch 2, also allow narrow load on some
  existing fields of the bpf_sock, which are "family", "type", "protocol"
  and "src_port".  Only allow loading from first byte for now.
  i.e. does not allow narrow load starting from the 2nd byte.
- Add some narrow load tests to the test_verifier's sock.c

Martin KaFai Lau (7):
  bpf: Add a bpf_sock pointer to __sk_buff and a bpf_sk_fullsock helper
  bpf: Add state, dst_ip4, dst_ip6 and dst_port to bpf_sock
  bpf: Refactor sock_ops_convert_ctx_access
  bpf: Add struct bpf_tcp_sock and BPF_FUNC_tcp_sock
  bpf: Sync bpf.h to tools/
  bpf: Add skb->sk, bpf_sk_fullsock and bpf_tcp_sock tests to
    test_verifer
  bpf: Add test_sock_fields for skb->sk and bpf_tcp_sock

 include/linux/bpf.h                           |  42 ++
 include/uapi/linux/bpf.h                      |  72 ++-
 kernel/bpf/verifier.c                         | 159 ++++--
 net/core/filter.c                             | 495 +++++++++++-------
 tools/include/uapi/linux/bpf.h                |  72 ++-
 tools/testing/selftests/bpf/Makefile          |   6 +-
 tools/testing/selftests/bpf/bpf_helpers.h     |   4 +
 tools/testing/selftests/bpf/bpf_util.h        |   9 +
 .../testing/selftests/bpf/test_sock_fields.c  | 327 ++++++++++++
 .../selftests/bpf/test_sock_fields_kern.c     | 152 ++++++
 .../selftests/bpf/verifier/ref_tracking.c     |   4 +-
 tools/testing/selftests/bpf/verifier/sock.c   | 384 ++++++++++++++
 tools/testing/selftests/bpf/verifier/unpriv.c |   2 +-
 13 files changed, 1493 insertions(+), 235 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/test_sock_fields.c
 create mode 100644 tools/testing/selftests/bpf/test_sock_fields_kern.c
 create mode 100644 tools/testing/selftests/bpf/verifier/sock.c

-- 
2.17.1