[net-next,v3,0/8] net/selftests: TCP-AO selftests updates

Message

Dmitry Safonov via B4 Relay Aug. 15, 2024, 9:32 p.m. UTC

First 3 patches are more-or-less cleanups/preparations.

Patches 4/5 are fixes for netns file descriptors leaks/open.

Patch 6 was sent to me/contributed off-list by Mohammad, who wants 32-bit
kernels to run TCP-AO.

Patch 7 is a workaround/fix for slow VMs. Albeit, I can't reproduce
the issue, but I hope it will fix netdev flakes for connect-deny-*
tests.

And the biggest change is adding TCP-AO tracepoints to selftests.
I think it's a good addition by the following reasons:
- The related tracepoints are now tested;
- It allows tcp-ao selftests to raise expectations on the kernel
  behavior - up from the syscalls exit statuses + net counters.
- Provides tracepoints usage samples.

As tracepoints are not a stable ABI, any kernel changes done to them
will be reflected to the selftests, which also will allow users
to see how to change their code. It's quite better than parsing dmesg
(what BGP was doing pre-tracepoints, ugh).

Somewhat arguably, the code parses trace_pipe, rather than uses
libtraceevent (which any sane user should do). The reason behind that is
the same as for rt-netlink macros instead of libmnl: I'm trying
to minimize the library dependencies of the selftests. And the
performance of formatting text in kernel and parsing it again in a test
is not critical.

Current output sample:
> ok 73 Trace events matched expectations: 13 tcp_hash_md5_required[2] tcp_hash_md5_unexpected[4] tcp_hash_ao_required[3] tcp_ao_key_not_found[4]

Previously, tracepoints selftests were part of kernel tcp tracepoints
submission [1], but since then the code was quite changed:
- Now generic tracing setup is in lib/ftrace.c, separate from
  lib/ftrace-tcp.c which utilizes TCP trace points. This separation
  allows future selftests to trace non-TCP events, i.e. to find out
  an skb's drop reason, which was useful in the creation of TCP-CLOSE
  stress-test (not in this patch set, but used in attempt to reproduce
  the issue from [2]).
- Another change is that in the previous submission the trace events
  where used only to detect unexpected TCP-AO/TCP-MD5 events. In this
  version the selftests will fail if an expected trace event didn't
  appear.
  Let's see how reliable this is on the netdev bot - it obviously passes
  on my testing, but potentially may require a temporary XFAIL patch
  if it misbehaves on a slow VM.

[1] https://lore.kernel.org/lkml/[e-mail]/
[2] https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=33700a0c9b56

Signed-off-by: Dmitry Safonov <[e-mail]>
---
Changes in v3:
- Corrected the selftests printing of tcp header flags, parsed from
  trace points
- Fixed an issue with VRF kconfig checks (and tests)
- Made check for unexpected trace events XFAIL, yet looking into the
  reason behind the fail
- Link to v2: https://lore.kernel.org/r/[e-mail]

Changes in v2:
- Fixed two issues with parsing TCP-AO events: the socket state and TCP
  segment flags. Hopefully, won't fail on netdev.
- Reword patch 1 & 2 messages to be more informative and at some degree
  formal (Paolo)
- Since commit e33a02ed6a4f ("selftests: Add printf attribute to
  kselftest prints") it's possible to use __printf instead of "raw" gcc
  attribute - switch using that, as checkpatch suggests.
- Link to v1: https://lore.kernel.org/r/[e-mail]

---
Dmitry Safonov (7):
      selftests/net: Clean-up double assignment
      selftests/net: Provide test_snprintf() helper
      selftests/net: Be consistent in kconfig checks
      selftests/net: Open /proc/thread-self in open_netns()
      selftests/net: Don't forget to close nsfd after switch_save_ns()
      selftests/net: Synchronize client/server before counters checks
      selftests/net: Add trace events matching to tcp_ao

Mohammad Nassiri (1):
      selftests/tcp_ao: Fix printing format for uint64_t

 tools/testing/selftests/net/tcp_ao/Makefile        |   3 +-
 tools/testing/selftests/net/tcp_ao/bench-lookups.c |   2 +-
 tools/testing/selftests/net/tcp_ao/config          |   1 +
 tools/testing/selftests/net/tcp_ao/connect-deny.c  |  25 +-
 tools/testing/selftests/net/tcp_ao/connect.c       |   6 +-
 tools/testing/selftests/net/tcp_ao/icmps-discard.c |   2 +-
 .../testing/selftests/net/tcp_ao/key-management.c  |  18 +-
 tools/testing/selftests/net/tcp_ao/lib/aolib.h     | 176 ++++++-
 .../testing/selftests/net/tcp_ao/lib/ftrace-tcp.c  | 549 +++++++++++++++++++++
 tools/testing/selftests/net/tcp_ao/lib/ftrace.c    | 466 +++++++++++++++++
 tools/testing/selftests/net/tcp_ao/lib/kconfig.c   |  31 +-
 tools/testing/selftests/net/tcp_ao/lib/setup.c     |  17 +-
 tools/testing/selftests/net/tcp_ao/lib/sock.c      |   1 -
 tools/testing/selftests/net/tcp_ao/lib/utils.c     |  26 +
 tools/testing/selftests/net/tcp_ao/restore.c       |  30 +-
 tools/testing/selftests/net/tcp_ao/rst.c           |   2 +-
 tools/testing/selftests/net/tcp_ao/self-connect.c  |  19 +-
 tools/testing/selftests/net/tcp_ao/seq-ext.c       |  28 +-
 .../selftests/net/tcp_ao/setsockopt-closed.c       |   6 +-
 tools/testing/selftests/net/tcp_ao/unsigned-md5.c  |  35 +-
 20 files changed, 1376 insertions(+), 67 deletions(-)
---
base-commit: a9c60712d71ff07197b2982899b9db28ed548ded
change-id: 20240730-tcp-ao-selftests-upd-6-12-4d3e53a74f3f

Best regards,

Comments

Dmitry Safonov Aug. 19, 2024, 5:19 p.m. UTC | #1

Going to update with v4, I see some netdev failures on non-appeared
trace events.
I need to review the synchronization on the tracer thread.

pw-bot: changes-requested

On Thu, 15 Aug 2024 at 22:32, Dmitry Safonov via B4 Relay
<[e-mail]> wrote:
>
> First 3 patches are more-or-less cleanups/preparations.
>
> Patches 4/5 are fixes for netns file descriptors leaks/open.
>
> Patch 6 was sent to me/contributed off-list by Mohammad, who wants 32-bit
> kernels to run TCP-AO.
>
> Patch 7 is a workaround/fix for slow VMs. Albeit, I can't reproduce
> the issue, but I hope it will fix netdev flakes for connect-deny-*
> tests.
>
> And the biggest change is adding TCP-AO tracepoints to selftests.
> I think it's a good addition by the following reasons:
> - The related tracepoints are now tested;
> - It allows tcp-ao selftests to raise expectations on the kernel
>   behavior - up from the syscalls exit statuses + net counters.
> - Provides tracepoints usage samples.
>
> As tracepoints are not a stable ABI, any kernel changes done to them
> will be reflected to the selftests, which also will allow users
> to see how to change their code. It's quite better than parsing dmesg
> (what BGP was doing pre-tracepoints, ugh).
>
> Somewhat arguably, the code parses trace_pipe, rather than uses
> libtraceevent (which any sane user should do). The reason behind that is
> the same as for rt-netlink macros instead of libmnl: I'm trying
> to minimize the library dependencies of the selftests. And the
> performance of formatting text in kernel and parsing it again in a test
> is not critical.
>
> Current output sample:
> > ok 73 Trace events matched expectations: 13 tcp_hash_md5_required[2] tcp_hash_md5_unexpected[4] tcp_hash_ao_required[3] tcp_ao_key_not_found[4]
>
> Previously, tracepoints selftests were part of kernel tcp tracepoints
> submission [1], but since then the code was quite changed:
> - Now generic tracing setup is in lib/ftrace.c, separate from
>   lib/ftrace-tcp.c which utilizes TCP trace points. This separation
>   allows future selftests to trace non-TCP events, i.e. to find out
>   an skb's drop reason, which was useful in the creation of TCP-CLOSE
>   stress-test (not in this patch set, but used in attempt to reproduce
>   the issue from [2]).
> - Another change is that in the previous submission the trace events
>   where used only to detect unexpected TCP-AO/TCP-MD5 events. In this
>   version the selftests will fail if an expected trace event didn't
>   appear.
>   Let's see how reliable this is on the netdev bot - it obviously passes
>   on my testing, but potentially may require a temporary XFAIL patch
>   if it misbehaves on a slow VM.
>
> [1] https://lore.kernel.org/lkml/[e-mail]/
> [2] https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=33700a0c9b56
>
> Signed-off-by: Dmitry Safonov <[e-mail]>
[..]

Sorry for the noise,
             Dmitry