====== Multicast DNS ======

[[http://www.multicastdns.org/|Multicast DNS (mDNS)]] is a part of Zero Configuration Networking (Zeroconf) and provides the ability to address hosts using DNS-like names without the need of an existing (unicast), managed DNS server.

The project is divided into two phases each with a set of sub-projects. The sub-projects in phase 1 is more or less
listed in the order they will be implemented in (they depend on each other), sub-projects in phase 2 is not listed
in the same order as they will be implemented.

  * [[MulticastDNS/Quickstart|Quick start]] - If you want to play with it.
  * [[MulticastDNS/SOCproposal|Original SoC proposal]]

A public mercurial repository with snapshots is available at http://hg.h3q.net/mdns

===== Phase 1 =====
==== Multicast DNS responder (mdnsd) ====
Status: Feature complete, requires testing and bugfixing.

This is the core responder daemon, performs multicast dns queries on behalf of clients and acts as
a unified cache to all clients.
Provides the ability to announce its own mdns records onto the network.

[[MulticastDNS/responderd|Details]]

==== Client API (libmdns) ====
Status: Working

Provides a easy programming interface to the client side of responderd.
Privileges operations include addition/removal of self-claimed records, while non-privileged operations
are limited to basic host lookup routines.

==== NSS module ====
Status: Complete

Uses libmdns and hooks into the name-service switch system to expose mdns aware-versions of name lookup functions.
Implements gethostby{name,name2,addr}, getaddrinfo and ghby{addr,name} (used by getipnodeby{name,addr} and getnameinfo).
Configuration file /etc/mdns.conf (similar to resolv.conf) controld the search space. Default is .local and private ip-addresses.

==== Command line utility ====
Status: Working

Utility named mdns (or similar) to provide basic host name lookup for debugging purposes and
to provide a way to dynamically add and remove self-claimed mdns records.
It currently supports resolving names, add/remove/list names and resources and view/flush cache,
its feature set is in sync with features provided by libmdns.

===== Phase 2 =====
==== Service Discovery integration ====
Status: Not started (Open task)

Create an application to do both multicast (libmdns) and unicase service discovery.
The previous idea with a separate library is probably overkill at the moment.

==== Avahi library wrapper (mdns_compat_avahi) ====
Status: Not started (Open task)

A wrapper library around libmdns to allow avahi-aware applications to work with mdns_responderd.
It seems most normal avahi consumers performs queries through d-bus so this compat library will probably
mimic this interface. The api avahi-core exposes will probably not be covered.

==== dns_sd library wrapper (mdns_compat_dns_sd) ====
Status: Not started (Open task)

A wrapper library around libmdns (and possibly libsd) to allow apple dns_sd-aware applications to work with mdns_responderd.
The API header (dns_sd.h) is released by Apple under a BSD-license.

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