Re: Problem with checksum offloading on RPi3 (PF + Jails involved)
John-Mark Gurney <[email protected]>
| Newsgroups | gmane.os.freebsd.devel.arm,gmane.os.freebsd.devel.hackers |
|---|---|
| Message-ID | <[email protected]> |
Kristof Provost wrote this message on Thu, Oct 29, 2020 at 21:30 +0100:
> On 29 Oct 2020, at 16:30, Carsten Bäcker wrote:
> > Sure, i am willing to help.
> >
> > Device is a Raspberry Pi 3B (not +), using the onboard-ethernet.
> > I attached a bunch of information.
> >
> > Configuration is stripped down to the minimum required to reproduce
> > the
> > problem.
> >
> Okay, so that???s an SMC2 LAN9514_ETH device.
> That???s the dev/usb/net/if_smsc.c driver.
>
> However, before we dig into that driver we should make sure that we???re
> really looking at a checksum problem.
> It???s entirely normal for TX checksums to be incorrect when logged on
> the sending host itself (if the hardware does checksum offloading the
> checksum in the packet sent to the MAC is incorrect, and left to the
> hardware to fix).
>
> So, can you confirm that the `"[bad udp cksum 0xe58a -> 0x482d!]` you
> reported was on an inbound packet? And let???s be safe: try to capture
> packets on a different machine. That???ll give us the true packet, after
> the hardware has done checksum calculations.
One interesting point is that the smsc driver claims to not do TX offload,
and a brief check shows that it doesn't allow a user to set the TXCSUM.
I was thinking that the bad checksum might be due to tcpdump just
complaining.
does netstat -s show packets being received w/ bad checksums?
--
John-Mark Gurney Voice: +1 415 225 5579
"All that I will do, has been done, All that I have, has not."
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