Re: [dns-privacy] a qname minimization algorithm

Tony Finch <dot@dotat.at> Thu, 20 March 2014 17:41 UTC

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Date: Thu, 20 Mar 2014 17:41:04 +0000
From: Tony Finch <dot@dotat.at>
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Subject: Re: [dns-privacy] a qname minimization algorithm
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Stephane doesn't like this because it is too specific, but I thought it
would be useful to have something concrete to discuss...

(0) If the query can be answered from the cache, do so, otherwise iterate
as follows:

(1) Find closest enclosing NS RRset in your cache. The owner of this NS
RRset will be a suffix of the QNAME - the longest suffix of any NS RRset
in the cache. Call this PARENT.

(2) Initialize CHILD to the same as PARENT.

(3) If CHILD is the same as the QNAME, resolve the original query using
PARENT's name servers, and finish.

(4) Otherwise, add a label from the QNAME to the start of CHILD.

(5) If you have a negative cache entry for the NS RRset at CHILD, go back
to step 3.

(6) Query for CHILD IN NS using PARENT's name servers. The response can
be:

(6a) A referral. Cache the NS RRset from the authority section and go back
to step 1.

(6b) An authoritative answer. Cache the NS RRset from the answer section
and go back to step 1.

(6c) An NXDOMAIN answer. Return an NXDOMAIN answer in response to the
original query and stop.

(6d) A NOERROR/NODATA answer. Cache this negative answer and go back to
step 3.

Tony.
-- 
f.anthony.n.finch  <dot@dotat.at>  http://dotat.at/
Northwest FitzRoy: Northwesterly 5 or 6, backing westerly or southwesterly 6
to gale 8. Rough or very rough. Showers. Good.