Re: [PATCH v8 net-next 3/4] ipv4/udp: Add 4-tuple hash for connected socket

[Philo Lu]

On 2024/11/12 22:58, Paolo Abeni wrote:
> On 11/8/24 06:48, Philo Lu wrote:
> [...]
> > Signed-off-by: Philo Lu <lulie@xxxxxxxxxxxxxxxxx>
> > Signed-off-by: Cambda Zhu <cambda@xxxxxxxxxxxxxxxxx>
> > Signed-off-by: Fred Chen <fred.cc@xxxxxxxxxxxxxxx>
> > Signed-off-by: Yubing Qiu <yubing.qiuyubing@xxxxxxxxxxxxxxx>
>
> [...]
> > @@ -2937,7 +3128,7 @@ struct proto udp_prot = {
> >   	.owner			= THIS_MODULE,
> >   	.close			= udp_lib_close,
> >   	.pre_connect		= udp_pre_connect,
> > -	.connect		= ip4_datagram_connect,
> > +	.connect		= udp_connect,
> >   	.disconnect		= udp_disconnect,
> >   	.ioctl			= udp_ioctl,
> >   	.init			= udp_init_sock,
>
> 2 minor notes, possibly not needing a repost:
>
> - The SoB chain looks strange, do you mean co-developed-by actually?

Yes, we're all involved in the development. I think it could be 
indicated by SoBs (and all of us agree with this). Please let me know if 
I'm wrong :)

Or strictly as [1], it should be:

Co-developed-by: Cambda Zhu <cambda@xxxxxxxxxxxxxxxxx>
Signed-off-by: Cambda Zhu <cambda@xxxxxxxxxxxxxxxxx>
Co-developed-by: Fred Chen <fred.cc@xxxxxxxxxxxxxxx>
Signed-off-by: Fred Chen <fred.cc@xxxxxxxxxxxxxxx>
Co-developed-by: Yubing Qiu <yubing.qiuyubing@xxxxxxxxxxxxxxx>
Signed-off-by: Yubing Qiu <yubing.qiuyubing@xxxxxxxxxxxxxxx>
Signed-off-by: Philo Lu <lulie@xxxxxxxxxxxxxxxxx>

[1]
https://www.kernel.org/doc/html/latest/process/submitting-patches.html#when-to-use-acked-by-cc-and-co-developed-by

> - udplite is not touched. AFAICS should not be a problem - just the
> feature will not be available for udplite. 

Agreed. Theoretically, the feature relies on udp4_hash4/udp6_hash4 when 
connecting, and all other functions including lookup/unhash/rehash 
always check "hashed4" firstly, and do nothing if it's false (which is 
the case for udplite).

AFAICT, the effects to udplite include:
- Additional memory consumption in udp_sock and udptable
- Control path: udp_hashed4 checking when unhash/rehash
- Data path: udp_has_hash4 checking when lookup
             (like unconnected sks in udp)

> I'm wondering if syzbot could
> prove me wrong about "not being a problem" (usually it's able to do that;)
>
> /P

Thanks.
--
Philo