[ntpwg] Pending NTP WG Last Call on Autokey

[David L. Mills]

Danny,

Don't fool with the length field. This goes cross puposes with other 
protocols such as IP and UDP. We are not going to see hundreds or even 
dozens of extension field types in NTP. What you suggest creates a 
ghetto for Autokey and does not provide a framework for 
type/version/opcode encoding. No proposal is complete without that 
encoding. The solution I proposed is completely adequate for whatever 
purpose extension fields might be used for; the implied generality is 
not worth the obscurity and incompatible model it creates.

Dave

Danny Mayer wrote:

> Dave,
>
> Absolutely not. We need to do this now before there are too many 
> implementations in the field. Do it now and get it over with.
>
> Danny
> David L. Mills wrote:
>
>> Danny,
>>
>> We are having a violent disagreement. The disagreement will continue 
>> with enthusiasm. Stay out of the length field. Leave things as they 
>> are and get this damn puppy out the door. When a new appliation 
>> surfaces for the extension fields, consider a revised format and junk 
>> the existing format.
>>
>> Dave
>>
>> Danny Mayer wrote:
>>
>>> Dave,
>>>
>>> I'm not buying it. I don't give a hoot about prior art. I'm trying 
>>> to fix the original problem of your overloading the type field with 
>>> private  codes. This is a workaround to allow the old usage to 
>>> continue to work while the code is upgraded to the correct usage and 
>>> to allow interoperation between the old and the new. The old will be 
>>> obsoleted after several releases.
>>>
>>> Danny
>>> David L. Mills wrote:
>>>
>>>> Danny,
>>>>
>>>> No sell. There are numeous examples of prior art in the use of a 
>>>> 16-bit length field in IP and UDP. I do not think it clean at all 
>>>> to poach on the length field. In any case, it doesn't really make 
>>>> much difference. What you see is what you get unless you have a 
>>>> specific proposal for a competitive protocol. Right now I don't 
>>>> hear anything.
>>>>
>>>> Dave
>>>>
>>>> Danny Mayer wrote:
>>>>
>>>>> Dave,
>>>>>
>>>>>
>>>>> You misunderstand me. I'm proposing that autokey complies as well. 
>>>>> conformance bit set to 1 indicates that you are conforming to the 
>>>>> protocol while conformance bit 0 (which it would have to be in 
>>>>> order to be the top bit of the length field) would mean the old 
>>>>> format and would be non-compliant with the autokey protocol and 
>>>>> the NTPv4 spec. The old autokey usage of the field type would go 
>>>>> away.
>>>>>
>>>>>
>>>>> I'll send you the layout at little layer.
>>>>>
>>>>>
>>>>> Danny
>>>>>
>>>>>
>>>>> David L. Mills wrote:
>>>>>
>>>>>> Dannt,
>>>>>>
>>>>>>
>>>>>> Each of us has proposed stealing bits from the length field or 
>>>>>> the code fields. I find stealing from the length field inelegant, 
>>>>>> while you might find theft of code bits crude. Your proposal 
>>>>>> cleaves Autokey from any other and does not necessarily provide 
>>>>>> for multiple others. I prefer my proposal.
>>>>>>
>>>>>>
>>>>>> Dave
>>>>>>
>>>>>>
>>>>>> Danny Mayer wrote:
>>>>>>
>>>>>>
>>>>>>> Dave,
>>>>>>>
>>>>>>>
>>>>>>> My proposal that I sent out quite a long time ago was to steal a 
>>>>>>> bit from the length field and set it to 1 for the updated 
>>>>>>> protocol so that the particulars of the autokey protocol remains 
>>>>>>> private inside the header extension itself and keeps it outside 
>>>>>>> the field type. That way the servers (including those of NIST, 
>>>>>>> USNO, etc.) can continue to work with both versions (the old and 
>>>>>>> the new). The old clients (servers) will continue to work. 
>>>>>>> Taking away one bit from the length field reduces the maximum 
>>>>>>> extension length from 65535 to 32767 which I don't think we will 
>>>>>>> ever need or can use.
>>>>>>>
>>>>>>>
>>>>>>> It's this lack of privacy of this data that causes 
>>>>>>> interoperability problems between Autokey and Microsoft's 
>>>>>>> MS-SNTP protocols, otherwise this issue would never have arisen.
>>>>>>>
>>>>>>>
>>>>>>> Danny
>>>>>>>
>>>>>>>
>>>>>>> David L. Mills wrote:
>>>>>>>
>>>>>>>
>>>>>>>> Danny,
>>>>>>>>
>>>>>>>>
>>>>>>>> I hear no proposals about extension fields other than my last 
>>>>>>>> proposed rewrite of that section. There really is no wiggle 
>>>>>>>> room other than deprecating Autokey in its present form and 
>>>>>>>> reformatting the headers. I am not opposed to that in 
>>>>>>>> principle, but others, specificlly USNO, have not been heard from.
>>>>>>>>
>>>>>>>>
>>>>>>>> Dave
>>>>>>>>
>>>>>>>>
>>>>>> _______________________________________________
>>>>>>
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>>>>>>
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>>>>>>
>>>>>> https://lists.ntp.org/mailman/listinfo/ntpwg
>>>>>>
>>>>>>
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>>
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