middleware: caching

[miekg]

a caching middleware

[miekg]

Should we cache RRset or complete messages? The former is how you should do it, but what it that leads to a partial answer? Then you need to get fetch it from somewhere.. do you then invoke the next middleware? That could work.
Or you could cache complete answers, but then there is a problem of multiple clients with different buffer sizes (or even transport), i.e. you can't re-use a TCP message when a client comes asking via UDP.

The first approach makes most sense, it's RFC compliant, and if you find that answer incomplete just hand off to the next middleware.

[miekg]

question still is... when is an answer incomplete.... In this example it can be detected. www.miek.nl is a cname to a.miek.nl:

;; ANSWER SECTION:
www.miek.nl.        1800    IN  CNAME   a.miek.nl.
a.miek.nl.      1765    IN  A   139.162.196.78

So if I have the CNAME, but not the target, which is inbaliwick I should just hand hand off...?