> Also, as I mentioned during the meeting, I double-checked the current
> implementation of IPv6 stack (Linux/BSD). If implementing 4rd-u, IPv6
> stack gives received IPv6 packet to 4rd-u module after processing it.
> But, according to the current implementation of IPv6 stack, IPv6
> stack totally removes IPv6 fragment header when IPv6 stack finds IPv6
> fragment header and processes it.
> Since 4rd-u module gets the packet after IPv6 stack processes the
> packet, IPv6 fragment header is not present when 4rd-u module gets
> the packet. 4rd-u utilizes IPv6 fragment header to carry some of IPv4
> information. But all information embedded in IPv6 fragment header is
> disappeared in IPv6 stack before 4rd-u module gets the packet. Hence,
> in order to keep/pass the information embedded in IPv6 fragment
> header to 4rd-u module, I think the existing IPv6 stack needs to be
Depends how you implement it. I can think of at least one way to do it
on Linux without touching the IPv6 stack. (with NF hooks)