Problem with checksum offloading on RPi3 (PF + Jails involved)

[Kristof Provost]

On 29 Oct 2020, at 14:29, Carsten Bäcker wrote:
> Hi Hackers,
>
> just stumbled upon a problem on my RPi3, but i am not sure if this is
> arm-related.
>
> Running System:
> "FreeBSD generic 12.1-RELEASE-p9 FreeBSD 12.1-RELEASE-p9 r365508
> GENERIC  arm64"
>
> I created a jail and set up NAT using PF. Same configuration runs
> perfectly on my server.
> However the jail was unable to resolve hostnames.
>
> After enabling pflog for the NAT-rules i noticed these errors:
> "[bad udp cksum 0xe58a -> 0x482d!]"
>
> So i disabled checksum offloading and everything worked fine.
> "ifconfig ue0 -rxcsum"
>
> Any chance to get this fixed?
>
First someone’s going to have to be able to reproduce it.

I fixed issues related to checksums in pf years ago, and while I’ve 
heard vague reports that it still wasn’t fixed in all cases I’ve not 
yet been able to reproduce (or even have someone else reproduce) those 
issues.

My initial suspicion would fall to the network driver rather than pf 
itself.
Let’s start by figuring out which one that is.

Presumably you’ve got a USB ethernet thing plugged in. Which one? 
(`sudo usbconfig dump_device_desc` will help).

Best,
Kristof