Subject: [BEHAVE] ICMP extensions

From: marcelo bagnulo braun <[email-masked]>
Date: Fri, 30 Oct 2009 12:19:49 +0100

Hi,

I am trying to understand how to handle ICMP extensions.

In the current draft, the text covering extensions is:

2.3. Translating ICMPv4 Headers into ICMPv6 Headers

...

         ICMP Error Payload  The [RFC4884] length field should be
            updated to reflect the changed length of the datagram.
            There are two cases for the length field modifications.
            That the translated packet is created from scratch and the
            length field never is filled in.  Then an ICMP extension
            will result in that it will be treated as part of the
            original datagram field.  If the IP payload is copied and
            then modified then the length field will be unmodified while
            the original datagram field will become longer by the
            address translation from v4->v6.  Thus cutting off the end
            of the original datagram field for ICMP extension aware
            receivers. information.

However, i have not found text covering the ICMP extension translation 
in the other direction and afaiu, icmpv6 messages can also contain 
extension, correct?

Regards, marcelo