Re: Problem with checksum offloading on RPi3 (PF + Jails involved)
"Kristof Provost" <[email protected]>
| Newsgroups | gmane.os.freebsd.devel.hackers,gmane.os.freebsd.devel.arm |
|---|---|
| Message-ID | <[email protected]> |
On 3 Nov 2020, at 20:14, John-Mark Gurney wrote: > Kristof Provost wrote this message on Sun, Nov 01, 2020 at 19:48 > +0100: >> On 31 Oct 2020, at 16:06, Carsten Bäcker wrote: >>> Packet-capture from the router is attached. >>> >> Okay??? but that doesn???t actually demonstrate anything at all. >> It shows an outbound packet with an incorrect checksum. See what >> I???ve >> mentioned before about checksums potentially being calculated by >> hardware. >> Given that there???s been a reply to that DNS query the checksum >> clearly >> got set correctly after the packet was captured. > > Actually, isn't that odd that the outbound checksum is wrong? Since > the chip doesn't advertise (or it shouldn't) tx checksum handling, > FreeBSD's stack should have computed the checksum. > Bear in mind that this capture was made with pflog, not the usual BTF_MTAP() in the driver. That means it was captured before the stack does checksum calculations. Just before it, in fact. See ip_output(). The checksum calculation is pretty much immediately after the pfil hook. Best regards, Kristof _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[email protected]"