[Ntp] Temporary extension field types for NTPv5

[David Venhoek <[e-mail]>]

Dear All,

I have made a pull request on Miroslav's NTPv5 draft git repository to
add temporary extension field type identifiers to all of the new
extension fields. These have been taken from Miroslav's implementation
where available, and extended logically elsewhere.

I have also added a temporary extension field for indicating which
draft version is used by an implementation to make this easier to
track for further changes.

For all of these extension fields, the extension field types are in
the experimental 0xf000-0xffff range per the ntp-registries draft.

For those uncomfortable with git, the diff is included below.

Kind regards,
David Venhoek

--- a/ntp-ntpv5.xml
+++ b/ntp-ntpv5.xml
@@ -408,8 +408,23 @@
         server, also the Reference IDs Request and Response extension fields to
         enable detection of synchronization loops.</t>

+      <section title="Draft Identification Extension Field">
+        <t>Note to the editors: this section must be removed before
final publication.</t>
+
+        <t>This field, with type 0xFFFF, is used to indicate which
draft of the specification
+          an implementation is based upon. It MUST be included in any
NTPv5 message produced
+          by an implementation based on a draft of this
specification, and MUST NOT be included
+          in any NTPv5 message produced by an implementation based on
the final version of
+          this specification.</t>
+
+        <t>The contents of this field MUST be the full name,
including version number, of
+          the draft upon which the implementation is based, encoded
as an ASCII string.</t>
+
+        <t>Note: the content of this field MUST NOT be null terminated</t>
+      </section>
+
       <section title="Padding Extension Field">
-        <t>This field is used by servers to pad the response to the same length
+        <t>This field, with type [[TBD]] (draft: 0xF501), is used by
servers to pad the response to the same length
           as the request if the response does not contain all requested
           extension fields, or some have a variable length. It can have any
           length. The data field of the extension field SHOULD contain zeros
@@ -419,7 +434,7 @@
       </section>

       <section title="MAC Extension Field">
-        <t>This field authenticates the NTPv5 message with a symmetric key.
+        <t>This field, with type [[TBD]] (draft: 0xF502),
authenticates the NTPv5 message with a symmetric key.
           Implementations SHOULD use the MAC specified in <xref
           target="RFC8573">RFC8573</xref>. The extension field MUST be the last
           extension field in the message unless an extension field is
@@ -503,7 +518,7 @@
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-|             Type              |             Length            |
+| Type = [[TBD]] (draft 0xF503) |             Length            |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |            Offset             |                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
@@ -523,7 +538,7 @@
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-|             Type              |             Length            |
+| Type = [[TBD]] (draft 0xF504) |             Length            |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 .                                                               .
 .                  Bloom filter chunk (variable)                .
@@ -548,7 +563,7 @@
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-|             Type              |             Length            |
+| Type = [[TBD]] (draft 0xF505) |             Length            |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | Min. Version  | Max. Version  |            Reserved           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
@@ -586,7 +601,7 @@
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-|             Type              |             Length            |
+| Type = [[TBD]] (draft 0xF506) |             Length            |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 +                       Origin Correction                       +
@@ -696,7 +711,7 @@
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-|             Type              |             Length            |
+| Type = [[TBD]] (draft 0xF507) |             Length            |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 |                      Reference Timestamp (64)                 |
@@ -735,7 +750,7 @@
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-|             Type              |             Length            |
+| Type = [[TBD]] (draft 0xF508) |             Length            |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                            Epoch ID                           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+