RE: [PATCH net-next v3] tcp: add TCP_ECN and TCP_ECN_OPTION socket options

[SandeepI]

> -----Original Message-----
> From: Jakub Kicinski <kuba@xxxxxxxxxx>
> Sent: 16 September 2026 05:28
> To: Irlanki Sandeep <irlanki.s@xxxxxxxxxxx>
> Cc: netdev@xxxxxxxxxxxxxxx; bpf@xxxxxxxxxxxxxxx; davem@xxxxxxxxxxxxx;
> edumazet@xxxxxxxxxx; pabeni@xxxxxxxxxx; ncardwell@xxxxxxxxxx;
> ast@xxxxxxxxxx; daniel@xxxxxxxxxxxxx; andrii@xxxxxxxxxx; corbet@xxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; lorenzo@xxxxxxxxxx; maze@xxxxxxxxxx;
> sporeba@xxxxxxxxxx; motomuman@xxxxxxxxxx; srihari.k@xxxxxxxxxxx;
> g.pokhra@xxxxxxxxxxx; r.kumawat@xxxxxxxxxxx;
> raj.kumars@xxxxxxxxxxx; ts413.lee@xxxxxxxxxxx
> Subject: Re: [PATCH net-next v3] tcp: add TCP_ECN and TCP_ECN_OPTION
> socket options
> 
> On Fri, 11 Sep 2026 14:41:48 +0530 Irlanki Sandeep wrote:
> > Currently, ECN and Accurate ECN (AccECN) configurations in the Linux
> > kernel are controlled globally via the net.ipv4.tcp_ecn and
> > net.ipv4.tcp_ecn_option sysctl variables. This global approach lacks
> > the granularity required for modern multi-application runtimes.
> 
> CI (bpf-ci) reports a failure to build tools/testing/selftests/bpf on all
tested
> toolchains/architectures (x86-64 gcc-15, x86-64 llvm-21, s390x gcc-15,
aarch64
> gcc-15) after this series. The build breaks in
> progs/setget_sockopt.c:
> 
>     progs/setget_sockopt.c:67:11: error: use of undeclared identifier
> 'TCP_ECN'
>             { .opt = TCP_ECN, .new = 3, .expected = 3, .restore = 255, },
>     progs/setget_sockopt.c:68:11: error: use of undeclared identifier
> 'TCP_ECN_OPTION'
>             { .opt = TCP_ECN_OPTION, .new = 2, .expected = 2, .restore =
255, },

Thanks for the report.

TCP_ECN and TCP_ECN_OPTION have been defined in
tools/testing/selftests/bpf/progs/bpf_tracing_net.h to resolve the
compilation failure in progs/setget_sockopt.c.

This has been addressed in v4:
https://lore.kernel.org/all/20260916050255.1379192-1-irlanki.s@xxxxxxxxxxx/

Thanks,
Sandeep.