Re: Turning routers into hosts (Re: Death by extension header (was:RE: New Version Notification for draft-li-6man-hbh-fwd-hdr-00.txt))

On 14-Jul-20 09:23, Mark Smith wrote:
> On Tue, 14 Jul 2020 at 06:02, Toerless Eckert <tte@cs.fau.de> wrote:
>>
>> On Mon, Jul 13, 2020 at 03:00:44PM -0300, Fernando Gont wrote:
>>> On 10/7/20 15:32, Toerless Eckert wrote:
>>>> IMHO: See my email earlier in the thread about punting stuff to slow-path, especially when/before
>>>> you figure out that you should have just ignored something at linerarte.
>>>>
>>>> Aka: not sufficiently prescriptive RFCs + bad implementations == extension header based features killed in deployments.
>>>
>>> Indeed. And add to that that the EH structure itself seems to be rather
>>> unfriendly with some popular hardware architectures. (unless with "not
>>> sufficiently prescriptive RFCs" you are meaning to set the maximum EH-header
>>> chain length to some sane value that folks might agree to comply with).
>>
>> I think we might want to start with a draft collecting what we think to
>> kow about the problem and figure out if we can structure it accordingl
>> to make sense out of it to make progress that is not just incrementally fixing
>> one single bit.
>>
> 
> I think one of the first sections needs to be titled:
> 
> "Turning Routers into Hosts"

Are you sure you don't mean "Turning Routers into Packet Manglers"?

Regards,
   An author of RFC3234

> 
> because in-flight processing of packets' EHs, payloads etc, rather
> than just dumb, fast and simple forwarding them, is host processing of
> packets.
> 
> How to tell it's host processing?
> 
> - processing of packets requires going past the IPv6 fixed header
> 
> - in-flight processing would fail if everything but the fixed header
> was encrypted
> 
> - processing beyond the fixed (forwarding) header is occuring at a
> node that *doesn't* hold the packet's destination address:
> 
> 
> RFC8200:
> 
> router       a node that forwards IPv6 packets not explicitly
>                 addressed to itself.  (See Note below.)
> 
>    host         any node that is not a router.  (See Note below.)
> 
> (Note is about a node's interfaces being forwarding or not)
> 
> 
> In this discussion and similar, people are really discussing paths
> between a packet's original source and a final destination constructed
> of a set of packet host processing hops.
> 
> 
> Regards,
> Mark.
> 
> 
> 
>> Cheers
>>     Toerless
>>
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