Re: [Technical Errata Reported] RFC8200 (5933)

[Brian E Carpenter <[e-mail]>]

Yes, a note that updating Segments Left is legal would fix it I think.

Regards
   Brian Carpenter

On 12-Dec-19 15:50, Fernando Gont wrote:
> On 11/12/19 21:07, Brian E Carpenter wrote:
>> On 11-Dec-19 16:27, RFC Errata System wrote:
>> ....
>>
>>> 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, 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. 
>>
>> I'm seeing a problem here. The Segments Left field of the routing header
>> must be decremented at the end of each segment. That's processing the
>> RH in my book, and it will occur when Segments Left >0.
> 
> It seems the problem is not related with this text, but rather with the
> fact that it omits RH-specific text as for the HbHO and DO headers.
> 
> i.e., HbhO, DO that precedes a routing header, and the routing header
> are exceptions to the rule.
> 
> (The text regarding SL==0 is because it's essentially impossible to tell
> where in the type-specific data of a RH the final destination will be).
> 
> So.. how about if the text above is expanded to "Extension headers
> (except for the Hop-by-Hop Options header, the ROuting Header, or a
> Destination Options header preceding a Routing header)"
> 
> ...and then RH-specific text (similar as for HbH or DO that precedes a
> RH) is added?
> 
> Thanks!
> 
> Cheers,
>