Re: [Technical Errata Reported] RFC8200 (5933)

[Alexandre Petrescu <[e-mail]>]

Le 11/12/2019 à 04:27, RFC Errata System a écrit :
> The following errata report has been submitted for RFC8200,
> "Internet Protocol, Version 6 (IPv6) Specification".
> 
> --------------------------------------
> You may review the report below and at:
> https://www.rfc-editor.org/errata/eid5933
> 
> --------------------------------------
> Type: Technical
> Reported by: Fernando Gont <[e-mail]>
> 
> Section: 4
> 
> Original Text
> -------------
>     Extension headers (except for the Hop-by-Hop Options header) are not
>     processed, inserted, or deleted by any node along a packet's delivery
>     path, until the packet reaches the node (or each of the set of nodes,
>     in the case of multicast) identified in the Destination Address field
>     of the IPv6 header.
> 
>     The Hop-by-Hop Options header is not inserted or deleted, but may be
>     examined or processed by any node along a packet's delivery path,
>     until the packet reaches the node (or each of the set of nodes, in
>     the case of multicast) identified in the Destination Address field of
>     the IPv6 header.  The Hop-by-Hop Options header, when present, must
>     immediately follow the IPv6 header.  Its presence is indicated by the
>     value zero in the Next Header field of the IPv6 header.
> 
> 
> Corrected Text
> --------------
>     Extension headers (except for the Hop-by-Hop Options header, or a
>     Destination Options header preceding a Routing header) are not processed,
>     inserted, or deleted by any node along a packet's delivery path,

packet delivery path, slow path... two very distinct concepts.  One is 
in the network with real cables, the other is in a chip or on a bus with 
copper on a printed board.

>    until the
>     packet reaches the final destination node (or each of the set of final
>     destination nodes, in the case of multicast).
> 
>     For packets that do not include a Routing Header, the final destination
>     node is identified by the Destination Address field of the IPv6 header.
>     For packets that include a Routing Header, the final destination node is
>     identified by the Destination Address field of the IPv6 header only when
>     the Segments Left field of the Routing Header is 0.
> 
>     The Hop-by-Hop Options header is not inserted or deleted, but may be
>     examined or processed by any node along a packet's delivery path,
>     until the packet reaches the final destination node (or each of the set of
>     final destination nodes, in the case of multicast). The Hop-by-Hop Options
>     header, when present, must immediately follow the IPv6 header.  Its
>     presence is indicated by the value zero in the Next Header field of the
>     IPv6 header.
> 
>     A Destination Options header preceding a Routing Header is not
>     processed, inserted, or deleted by any node along a packet's delivery
>     path, until the packet reaches the destination node (or each of the set
>     of destination nodes, in the case of multicast) identified by the
>     Destination Address field of the IPv6 header. This means that  a
>     Destination Options header preceding a Routing Header will be
>     processed by the first destination of the packet (specified by the
>     Destination Address field of the IPv6 header at the origin node) and by
>     each node listed in the Routing Header.
> 
> Notes
> -----
> This errata clarifies two different issues:
> 
> * It clarifies that nodes other than the final destination do not insert o remove extension headers.

This final destination is somehow a strange concept.  It can be a 
computer node that owns several addresses.  But this is difficult with 
virtualization.  Owning one address is difficult to prove as well.

In that sense, it would help to clarify the concept of 'final 
destination' by maybe using a tight relationship between an IP address 
and an identifier of a node.  Such an identifier could be a number in 
the BIOS, or something from a TPM or HSM (trust modules).

Otherwise, I can still interpret that clarification as allowing 
intermediary nodes to insert/remove EHs.

Alex

> 
> * It clarifies that the Destination Options header preceding a routing header *is* processed along the
>     packet delivery's path, but the node(s) identified by the Destination Address of the IPv6 header.
> 
> Instructions:
> -------------
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> 
> --------------------------------------
> RFC8200 (draft-ietf-6man-rfc2460bis-13)
> --------------------------------------
> Title               : Internet Protocol, Version 6 (IPv6) Specification
> Publication Date    : July 2017
> Author(s)           : S. Deering, R. Hinden
> Category            : INTERNET STANDARD
> Source              : IPv6 Maintenance
> Area                : Internet
> Stream              : IETF
> Verifying Party     : IESG
> 
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