Re: TCP checksum errors on mec0 on an O2

On 22/11/2019 16:15, George Harvey wrote:
> I'm running NetBSD 8.1 on a R5000/180 O2 and seeing a lot of stalls and
> hangs when using FTP to send files over the mec0 Ethernet interface.
> Small files (less than around 4k) transfer successfully, anything much
> larger fails. On the receiving machine, the files are truncated at
> exactly 2896 bytes.
> 
> Using WireShark on a separate machine, to sample the packets on the
> wire, I see that the first two packets are sent correctly and the third
> packet has a TCP checksum error. Data size in the packets is 1448
> bytes, which explains the 2896 bytes at the receiving end. I've had a
> look in if_mec.c and I can see the receive checksum routine,
> mec_rxcsum, but I don't see the transmit checksum. Is it done by the
> MACE chip or is it somewhere else in the code?

I ran into this issue earlier in the year on my r5k o2.
http://gnats.netbsd.org/54194

Sevan