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Re: VZ FIOS and Intel TCP IPv6 Checksum Offload problems


From: William Herrin <bill () herrin us>
Date: Sat, 27 Aug 2022 19:16:04 -0700

On Sat, Aug 27, 2022 at 12:00 PM Sean Donelan <sean () donelan com> wrote:
In some situations where a client machine is connected via some specific
Optical Network Terminals (ONTs), and data is appended after the packet
checksum, the network adapter can drop receive packets when using TCP-IPv6
Checksum Offload for receive traffic.

Hi Sean,

Do you happen to have any details on the bug? I note that the IPv6
header DOES NOT HAVE a checksum; it relies on the checksum in the
layer-2 frame. I'm not clear how you "append" bytes to the ethernet
frame "after" calculating the checksum, have the hardware checksum
fail but have the software checksum succeed.

Regards,
Bill Herrin


-- 
For hire. https://bill.herrin.us/resume/


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