[bind10-dev] DNS packet API: the name object

[Michael Graff]

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Jelte Jansen wrote:
> we might also want to think about how to efficiently do name compression, which
> makes it a bit more involved even if all rrs are stored in wire format, and if
> we want to be memory-efficient for in-memory zones; whether we need to have a
> separate name for every rr, or that we could have names that contain (class,
> type, ttl) tuples, which in turn contain rdata sets, and for dnssec the
> associated sigs and nsecs (yes yes, all database again). Perhaps some c++
> smartness could help in this regard, but i'm not completely up to speed on that yet.


I thought a little about that in fact.

Knowing where the names are is good, and the resource record itself is
best suited for that goal.  I would not want to see an API that did this:

  if (record->canCompress())
    record->renderCompressedWire(message)
  else
    record->renderUncompressedWire(message)
  end

but just a simple record->renderWire(message) or something.  The smarts
are under the hood.

Passing in the message (which might have things like a list of names
currently in the message, for compression purposes) allows the smartness
to be hidden.

Note that many APIs reverse this, and use message->addRecord().  This is
fine to build up a list of records, but I think the actual rendering
should be as I describe above.

- --Michael
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