Re: [PATCH 10/11] contrib: Add program to document and test assumptions about SO_REUSEADDR

[David Gibson <david@gibson.dropbear.id.au>]

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On Thu, Jul 04, 2024 at 11:21:21PM +0200, Stefano Brivio wrote:
> On Thu,  4 Jul 2024 14:58:34 +1000
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
> > For the approach we intend to use for handling UDP flows, we have some
> > pretty specific requirements about how SO_REUSEADDR works with UDP sockets.
> > Specifically SO_REUSEADDR allows multiple sockets with overlapping bind()s,
> > and therefore there can be multiple sockets which are eligible to receive
> > the same datagram.  Which one will actually receive it is important to us.
> > 
> > Add a test program which verifies things work the way we expect, which
> > documents what those expectations are in the process.
> > 
> > Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> > ---
> >  contrib/udp-behaviour/.gitignore           |   1 +
> >  contrib/udp-behaviour/Makefile             |  45 ++++
> >  contrib/udp-behaviour/common.c             |  66 ++++++
> >  contrib/udp-behaviour/common.h             |  47 ++++
> >  contrib/udp-behaviour/reuseaddr-priority.c | 240 +++++++++++++++++++++
> >  5 files changed, 399 insertions(+)
> 
> I reviewed these (10/11 and 11/11) a bit lightly, but they look sane to
> me. I just wonder: wouldn't it be better to have
> contrib/linux/udp-behaviour instead, so that it's consistent with the
> other stuff unter contrib/ (project names, kind of)?

Well.. if we ever port to something non-Linux, we'll need the same
socket behaviour there.  Indeed, that's one reason I think having
these test programs is valuable.  So I don't think 'linux/' is a great
pick.

In some ways contrib/ isn't really the right place for this.  Maybe
it would be better under doc/?  But at the moment that's more user
facing than developer facing documentation.

> By the way, I reviewed everything else except for 9/11. That will take
> me a bit longer. And for the rest, I just have nits that I could also
> take care of on merge.
> 

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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