madns (pronounced “madness”) is a DNS library written in Go for serving abstract zone files as an authoritative nameserver.
An abstract zone file is any object implementing this interface:
type Backend interface {
Lookup(qname string) ([]dns.RR, error)
}Import as gopkg.in/hlandau/madns.v1.
Zone files are easy to understand. They contain lists of records, each with an owner name, type, and type-specific data (as well as class and TTL).
However, DNS is more complicated than meets the eye. There are a series of complicated rules governing how zone file data is served. Thus, serving zones isn't as simple as just spitting out the matching records in response to queries.
madns aims to implement the glue between the DNS wire protocol (implemented in
Go by miekg/dns) and an abstract zone file. It is similar in this regard to
PowerDNS's pipe backend, and intentionally so.
The abstract zone interface doesn't include a 'qtype' parameter as in many cases this would mean calls would have to be repeated to check for the existence of e.g. CNAMEs. Since most owner names won't have a very large number of records, this shouldn't be a problem (unless, I suppose, you have some sort of application where returning records of a particular type is a lot more computationally expensive, and they can't be moved to another owner name).
Of course madns only serves records corresponding to a client's request, qtype-wise and otherwise.
Since madns is implemented as a library it can be easily embedded into a larger daemon.
madns builds on miekg/dns. It aims to offer a high-level interface on top of
the low level interface it provides.
madns supports DNSSEC and uses “NSEC3 white lies” (NSEC3NARROW in PowerDNS terminology).
© 2014 Hugo Landau <hlandau@devever.net> Licenced under the GPLv3 or later