Re: [DNSOP] HTTPS and SVBC key names.

[Ben Schwartz <[e-mail]>]

On Thu, Jul 16, 2020 at 3:50 PM Dick Franks <[e-mail]> wrote:

>
> On Thu, 16 Jul 2020 at 13:31, Ben Schwartz <[e-mail]> wrote:
>
>
>> On Thu, Jul 16, 2020, 4:07 AM Dick Franks <[e-mail]> wrote:
>>
>>>
>>> Beefed-up example from 5.3, where we know neither the key name nor how
>>> to interpret the value:
>>>
>>>     foosvc.example.net. 3600 IN SVCB    \# 9 000100ff350002beef
>>>       ; 1 . key65333=...
>>>
>>
>> Should this say "TYPE64" instead of SVCB?  Apart from that, this looks
>> right
>>
>
> No.  The IANA registry was updated on June 30 and perl
> Net::DNS::Parameters is generated from the XML. It will be in the next
> Net::DNS release.
>
>
>
>> Presentation format?
>>>
>>
>> key65333=\190\239
>>
>
> If this is a string, should this say?    key65333="\190\239"
>

Quotes are optional, as with <character-string>.  Quotes are only required
if the value contains whitespace.


>
>>> Also, why do (key,value) pairs need to be in ascending order on the
>>> wire, but can be in any order in the presentation format?
>>>
>>
>> The presentation format is optimized for humans and the wire format is
>> optimized for machines. In particular, when using the named keys it's not
>> obvious what the numeric ordering is, so keeping them in order when editing
>> a zone file by hand would be hard.
>>
>
> That does not answer the question.
> What is the reason for the keys to be in ascending order?
>

I think this was motivated primarily by a general belief that unnecessary
degrees of freedom should be removed, to minimize variation between
implementations.  Every variation is a chance for surprises, from buggy
interactions to information leakage.  It also potentially simplifies
validation of a record by the recipient.

There is also some inconsistency in the use of quotes.
>
> 2.3 has:
>
>   svc4.example.net.  7200  IN SVCB 3 svc4.example.net. (
>        alpn="bar" port="8004" echconfig="..." )
>
> 2.5.2 has:
>
>   svc2.example.net. 7200  IN HTTPS 1 . port=8002 echconfig="..."
>
> Is the port value an integer or a string, with the quotes being optional?
>
> The quotes are always optional, except when the presentation value
contains whitespace, regardless of the data type.


> Is the wire format a character string to be interpreted as an integer by the client,
> or a packed integer in network byte order?
>
> The port wire format value is a packed integer in network byte order.


>
>
> --Dick
>
>
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>>