Re: [PATCH net-next v2 2/2] selftests/bpf: verify syncookie statistics in tcp_custom_syncookie

From: Paolo Abeni

Date: Tue Apr 14 2026 - 05:21:03 EST


On 4/14/26 11:08 AM, Paolo Abeni wrote:
> On 4/14/26 7:50 AM, Kuniyuki Iwashima wrote:
>> On Fri, Apr 10, 2026 at 6:32 PM Jiayuan Chen <jiayuan.chen@xxxxxxxxx> wrote:
>>>
>>> Add read_tcpext_snmp() helper to network_helpers which reads a
>>> TcpExt SNMP counter via nstat, and use it in the tcp_custom_syncookie
>>> test to verify that LINUX_MIB_SYNCOOKIESRECV is incremented and
>>> LINUX_MIB_SYNCOOKIESFAILED stays unchanged across a successful
>>> BPF custom syncookie validation.
>>>
>>> The delta is captured between start_server() and accept(), which
>>> covers the full SYN/ACK/cookie-check path for one connection.
>>>
>>> Signed-off-by: Jiayuan Chen <jiayuan.chen@xxxxxxxxx>
>>> ---
>>> tools/testing/selftests/bpf/network_helpers.c | 22 +++++++++++++++++++
>>> tools/testing/selftests/bpf/network_helpers.h | 1 +
>>> .../bpf/prog_tests/tcp_custom_syncookie.c | 20 +++++++++++++++++
>>
>> As you touch bpf selftest helper files, please rebase on bpf-next
>> to avoid possible conflicts and tag bpf-next in the Subject.
>
> To hopefully minimize the conflicts handling I'm going to apply patch
> 1/2 to net-next. Please resubmit patch 2/2 to bpf-next after the
> relevant net core reach there.

Uhmm... the original feature went through the bpf tree, so I guess both
patches could/should via bpf-next. Hopefully conflict into the tcp code
should be minimal.

@Eric, @Daniel: please LMK if you prefer otherwise.
/P