Re: [Softwires] Fwd: New Version Notification for draft-chen-softwire-4rd-u-comment-00.txt

[Maoke <[e-mail]>]

postpone other parts, but focus on the checksum issue.
2012/4/11 Rémi Després [e-mail]

>
> 5.4 Impact c. - it is true that, in the IPv6 packet of a tunneled ICMPv4
> message, the ICMPv4 checksum doesn't ensure IPv6 address integrity. But
> this integrity can be ensured at tunnel exit by checking that CNPs do
> preserve checksum neutrality. This can be clarified by a complement in the
> 4rd-u security section.
>
>

1. this introduces another new semantics/logic of protocol stack
processing at exit CE. it is really hard to call it either IPv4 or IPv6.

2. even though this CNP works for the address integrity, unfortunately,
however, the checksum still provides integrity protection for packet length
and payload protocol type in both IPv4/ICMPv4 pair and IPv6/ICMPv6 pair.
they are involved either in IPv4 header checksum or in ICMPv6 checksum,
which covers the pseudo-header of IPv6. how could CNP protect these?

thanks for mentioning CNP here. i need to modify the concern for "address
integrity" to the concern for "integrity of addresses, packet length and
payload protocol type".

- maoke