Hi,
Thanks for finding these bugs! I'll post an updated version soon (2 patches
with no separate Kconfig patches, one LRO and one eHEA patch). See comments below.
Thanks,
Jan-Bernd
On Monday 30 July 2007 22:32, Andrew Gallatin wrote:
> I was working on testing the myri10ge patch, and I ran into a few
> problems. I've attached a patch to inet_lro.c to fix some of them,
> and a patch to myri10ge.c to show how to use the page based
> interface. Both patches are signed off by Andrew Gallatin
> <[email protected]>
>
> First, the LRO_MAX_PG_HLEN is still a problem. Minimally sized 60
> byte frames still cause problems in lro_gen_skb due to skb->len
> going negative. Fixed in the attached patch. It may be simpler
> to just drop LRO_MAX_PG_HLEN to ETH_ZLEN, but I'm not sure if
> that is enough. Are there "smart" NICs which might chop off padding
> themselves?
I'd tend to stick to an explicit check as implemented in your patch
for now
>
> Second, you still need to set skb->ip_summed = CHECKSUM_UNNECESSARY
> when modified packets are flushed, else the stack will see bad
> checksums for packets from CHECKSUM_COMPLETE drivers using the
> skb interface. Fixed in the attached patch.
I thought about it... As we do update the TCP checksum for aggregated
packets we could add a second ip_summed field in the net_lro_mgr struct
used for aggregated packets to support HW that does not have any checksum helper
functionality. These drivers could set this ip_summed field to CHECKSUM_NONE,
and thus leave the checksum check to the stack. I'm not sure if these old devices benefit
a lot from LRO. So what do you think?
>
> Fourth, I did some traffic sniffing to try to figure out what's going
> on above, and saw tcpdump complain about bad checksums. Have you tried
> running tcpdump -s 65535 -vvv? Have you also seen bad checksums?
> I seem to see this for both page- and skb-based versions of the driver.
>
Hmmm, can't confirm that. For our skb-based version I see
correct checksums for aggregated packets and for the page-based version as well.
I used: (tcpdump -i ethX -s 0 -w dump.bin) in combination with ethereal.
Don't see problems as well with your tcpdump command.
-
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