Re: [PATCH mptcp-next v5 0/3] only remove entry from local_addr_list when sending a REMOVE_ADDR

Hi Gang,

Sorry for the delay.

On 26/06/2026 12:24, [email protected] wrote:
>>
>> From: Geliang Tang <[email protected]>
>>  
>>  v5:
>>  - rebased.
>>  - add Matt's reviewed tags.
>>  - add a RM_ADDR from the server to the client as Sashiko suggested.
>>  - mptcpd tests (make check) are still OK after this modification.
>>
> Hi Matt,
> 
> Sorry for the off-list email before, I forget to cc the [email protected]
> 
> First, no offense intended — this is in no way a comment on this patch. 
> The patch itself looks good to me. I'm replying here only because the
> thought came up while reading it.
> 
> While looking at mptcpd recently, I noticed that 'make check' doesn't
> seem to exercise the userspace PM logic in a meaningful way. The
> userspace PM cases in test-commands issue the per-connection (mptcpd_pm_*)
> calls with a fake token that doesn't correspond to any real MPTCP connection,
> so they only really verify that the command dispatches and the genl request
> is sent without crashing.
> 
> This made me wonder whether it would be worthwhile to add functional tests
> for mptcpd within the selftest framework — for example, via a dedicated script
> (something like selftest_mptcpd.sh) that actually starts mptcpd with specific
> plugins (e.g., sspi) in a namespace/veth environment, and then asserts the
> expected path-manager behavior end-to-end.
> 
> In other words, I'm asking: does the community think mptcpd's userspace PM
> functionality deserves similar test coverage within selftest?

Good point. What about the opposite: adding such tests in mptcpd directly?

When mptcpd started to support the userspace PM, it was not easy to
access to a kernel with such support: either the old MPTCP fork, or a
v5.19 upstream kernel. The mptcpd project was and is still using GitHub
Actions for the CI. A few years ago, I suppose it was not planned to
build a kernel, start a VM and execute some tests on mptcpd side.

The situation is different now: tests are running on images using either
a v6.8 or a v6.17 base kernel:


https://github.com/actions/runner-images/blob/main/images/ubuntu/Ubuntu2204-Readme.md

https://github.com/actions/runner-images/blob/main/images/ubuntu/Ubuntu2404-Readme.md

I think that would be better to add such tests there, rather than adding
a dependence to mptcpd in the selftests where it sounds better to use
pm_nl_ctl to validate the userspace PM.

WDYT?

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.