[PATCH bpf-next v6 00/13] New nf_conntrack kfuncs for insertion, changing timeout, status

[Kumar Kartikeya Dwivedi <memxor@gmail.com>]

Introduce the following new kfuncs:
 - bpf_{xdp,skb}_ct_alloc
 - bpf_ct_insert_entry
 - bpf_ct_{set,change}_timeout
 - bpf_ct_{set,change}_status

The setting of timeout and status on allocated or inserted/looked up CT
is same as the ctnetlink interface, hence code is refactored and shared
with the kfuncs. It is ensured allocated CT cannot be passed to kfuncs
that expected inserted CT, and vice versa. Please see individual patches
for details.

Changelog:
----------
v5 -> v6:
v5: https://lore.kernel.org/bpf/20220623192637.3866852-1-memxor@gmail.com

 * Introduce kfunc flags, rework verifier to work with them
 * Add documentation for kfuncs
 * Add comment explaining TRUSTED_ARGS kfunc flag (Alexei)
 * Fix missing offset check for trusted arguments (Alexei)
 * Change nf_conntrack test minimum delta value to 8

v4 -> v5:
v4: https://lore.kernel.org/bpf/cover.1653600577.git.lorenzo@kernel.org

 * Drop read-only PTR_TO_BTF_ID approach, use struct nf_conn___init (Alexei)
 * Drop acquire release pair code that is no longer required (Alexei)
 * Disable writes into nf_conn, use dedicated helpers (Florian, Alexei)
 * Refactor and share ctnetlink code for setting timeout and status
 * Do strict type matching on finding __ref suffix on argument to
   prevent passing nf_conn___init as nf_conn (offset = 0, match on walk)
 * Remove bpf_ct_opts parameter from bpf_ct_insert_entry
 * Update selftests for new additions, add more negative tests

v3 -> v4:
v3: https://lore.kernel.org/bpf/cover.1652870182.git.lorenzo@kernel.org

 * split bpf_xdp_ct_add in bpf_xdp_ct_alloc/bpf_skb_ct_alloc and
   bpf_ct_insert_entry
 * add verifier code to properly populate/configure ct entry
 * improve selftests

v2 -> v3:
v2: https://lore.kernel.org/bpf/cover.1652372970.git.lorenzo@kernel.org

 * add bpf_xdp_ct_add and bpf_ct_refresh_timeout kfunc helpers
 * remove conntrack dependency from selftests
 * add support for forcing kfunc args to be referenced and related selftests

v1 -> v2:
v1: https://lore.kernel.org/bpf/1327f8f5696ff2bc60400e8f3b79047914ccc837.1651595019.git.lorenzo@kernel.org

 * add bpf_ct_refresh_timeout kfunc selftest

Kumar Kartikeya Dwivedi (10):
  bpf: Introduce BTF ID flags and 8-byte BTF set
  tools/resolve_btfids: Add support for resolving kfunc flags
  bpf: Switch to new kfunc flags infrastructure
  bpf: Add support for forcing kfunc args to be trusted
  bpf: Add documentation for kfuncs
  net: netfilter: Deduplicate code in bpf_{xdp,skb}_ct_lookup
  net: netfilter: Add kfuncs to set and change CT timeout
  selftests/bpf: Add verifier tests for trusted kfunc args
  selftests/bpf: Add negative tests for new nf_conntrack kfuncs
  selftests/bpf: Fix test_verifier failed test in unprivileged mode

Lorenzo Bianconi (3):
  net: netfilter: Add kfuncs to allocate and insert CT
  net: netfilter: Add kfuncs to set and change CT status
  selftests/bpf: Add tests for new nf_conntrack kfuncs

 Documentation/bpf/index.rst                   |   1 +
 Documentation/bpf/kfuncs.rst                  | 171 ++++++++
 include/linux/bpf.h                           |   3 +-
 include/linux/btf.h                           |  68 ++--
 include/linux/btf_ids.h                       |  64 +++
 include/net/netfilter/nf_conntrack_core.h     |  19 +
 kernel/bpf/btf.c                              | 120 +++---
 kernel/bpf/verifier.c                         |  14 +-
 net/bpf/test_run.c                            |  75 ++--
 net/ipv4/bpf_tcp_ca.c                         |  18 +-
 net/ipv4/tcp_bbr.c                            |  24 +-
 net/ipv4/tcp_cubic.c                          |  20 +-
 net/ipv4/tcp_dctcp.c                          |  20 +-
 net/netfilter/nf_conntrack_bpf.c              | 365 +++++++++++++-----
 net/netfilter/nf_conntrack_core.c             |  62 +++
 net/netfilter/nf_conntrack_netlink.c          |  54 +--
 tools/bpf/resolve_btfids/main.c               | 115 +++++-
 .../selftests/bpf/bpf_testmod/bpf_testmod.c   |  10 +-
 .../testing/selftests/bpf/prog_tests/bpf_nf.c |  64 ++-
 .../testing/selftests/bpf/progs/test_bpf_nf.c |  85 +++-
 .../selftests/bpf/progs/test_bpf_nf_fail.c    | 134 +++++++
 .../selftests/bpf/verifier/bpf_loop_inline.c  |   1 +
 tools/testing/selftests/bpf/verifier/calls.c  |  53 +++
 23 files changed, 1214 insertions(+), 346 deletions(-)
 create mode 100644 Documentation/bpf/kfuncs.rst
 create mode 100644 tools/testing/selftests/bpf/progs/test_bpf_nf_fail.c

-- 
2.34.1