[PATCH v3 bpf-next 00/11] bpf: Enable bpf_skc_to_* sock casting helper to networking prog type

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

This set allows networking prog type to directly read fields from
the in-kernel socket type, e.g. "struct tcp_sock".

Patch 2 has the details on the use case.

v3:
- ARG_PTR_TO_SOCK_COMMON_OR_NULL was attempted in v2.  The _OR_NULL was
  needed because the PTR_TO_BTF_ID could be NULL but note that a could be NULL
  PTR_TO_BTF_ID is not a scalar NULL to the verifier.  "_OR_NULL" implicitly
  gives an expectation that the helper can take a scalar NULL which does
  not make sense in most (except one) helpers.  Passing scalar NULL
  should be rejected at the verification time.

  Thus, this patch uses ARG_PTR_TO_BTF_ID_SOCK_COMMON to specify that the
  helper can take both the btf-id ptr or the legacy PTR_TO_SOCK_COMMON but
  not scalar NULL.  It requires the func_proto to explicitly specify the
  arg_btf_id such that there is a very clear expectation that the helper
  can handle a NULL PTR_TO_BTF_ID.

v2:
- Add ARG_PTR_TO_SOCK_COMMON_OR_NULL (Lorenz)

Martin KaFai Lau (11):
  bpf: Move the PTR_TO_BTF_ID check to check_reg_type()
  bpf: Enable bpf_skc_to_* sock casting helper to networking prog type
  bpf: Change bpf_sk_release and bpf_sk_*cgroup_id to accept
    ARG_PTR_TO_BTF_ID_SOCK_COMMON
  bpf: Change bpf_sk_storage_*() to accept ARG_PTR_TO_BTF_ID_SOCK_COMMON
  bpf: Change bpf_tcp_*_syncookie to accept
    ARG_PTR_TO_BTF_ID_SOCK_COMMON
  bpf: Change bpf_sk_assign to accept ARG_PTR_TO_BTF_ID_SOCK_COMMON
  bpf: selftest: Add ref_tracking verifier test for bpf_skc casting
  bpf: selftest: Move sock_fields test into test_progs
  bpf: selftest: Adapt sock_fields test to use skel and global variables
  bpf: selftest: Use network_helpers in the sock_fields test
  bpf: selftest: Use bpf_skc_to_tcp_sock() in the sock_fields test

 include/linux/bpf.h                           |   1 +
 include/net/bpf_sk_storage.h                  |   2 -
 include/uapi/linux/bpf.h                      |   1 +
 kernel/bpf/bpf_lsm.c                          |   4 +-
 kernel/bpf/verifier.c                         |  93 ++--
 net/core/bpf_sk_storage.c                     |  31 +-
 net/core/filter.c                             | 112 ++--
 net/ipv4/bpf_tcp_ca.c                         |  23 +-
 tools/include/uapi/linux/bpf.h                |   1 +
 tools/testing/selftests/bpf/Makefile          |   2 +-
 .../selftests/bpf/prog_tests/sock_fields.c    | 361 +++++++++++++
 ..._sock_fields_kern.c => test_sock_fields.c} | 165 +++---
 .../testing/selftests/bpf/test_sock_fields.c  | 482 ------------------
 .../selftests/bpf/verifier/ref_tracking.c     |  47 ++
 14 files changed, 633 insertions(+), 692 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/sock_fields.c
 rename tools/testing/selftests/bpf/progs/{test_sock_fields_kern.c => test_sock_fields.c} (61%)
 delete mode 100644 tools/testing/selftests/bpf/test_sock_fields.c

-- 
2.24.1