Digital Audio Access Protocol

The Digital Audio Access Protocol (DAAP) is the proprietary protocol introduced by Apple in its iTunes software to share media across a local network.

DAAP addresses the same problems for Apple as the UPnP AV standards address for members of the Digital Living Network Alliance (DLNA).

Description

The DAAP protocol was originally introduced in iTunes version 4.0.[1] Initially, Apple did not officially release a protocol description, but it has been reverse-engineered to a sufficient degree that reimplementations of the protocol for non-iTunes platforms have been possible. Recently, however, Apple has begun to license the protocol specification for commercial implementations.

A DAAP server is a specialized HTTP server, which performs two functions. It sends a list of songs and it streams requested songs to clients. There are also provisions to notify the client of changes to the server. Requests are sent to the server by the client in form of URLs and are responded to with data in application/x-dmap-tagged mime-type, which can be converted to XML by the client. iTunes uses the ZeroConf (also known as Bonjour) service to announce and discover DAAP shares on a local subnet. The DAAP service uses TCP port 3689 by default.[2]

DAAP is one of two media sharing schemes that Apple has currently released. The other, Digital Photo Access Protocol (DPAP), is used by iPhoto for sharing images. They both rely on an underlying protocol, Digital Media Access Protocol (DMAP).

Early versions of iTunes allowed users to connect to shares across the Internet, however, in recent versions only computers on the same subnet can share music (workarounds such as port tunneling are possible). The Register speculates that Apple made this move in response to pressure from the record labels.[3] More recent versions of iTunes also limit the number of clients to 5 unique IP addresses within a 24-hour period.

DAAP has also been implemented in other non-iTunes media applications such as Banshee, Amarok, Exaile (with a plugin), Songbird (with a plugin), Rhythmbox, and WiFiTunes.

DAAP authentication

Beginning with iTunes 4.2, Apple introduced authentication to DAAP sharing, meaning that the only clients that could connect to iTunes servers were other instances of iTunes. This was further modified in iTunes 4.5 to use a custom hashing algorithm, rather than the standard MD5 function used previously. Both authentication methods were successfully reverse engineered within months of release.[4]

With iTunes 7.0, a new 'Client-DAAP-Validation' header hash is needed when connecting to an iTunes 7.0 server. This does not affect third-party DAAP servers, but all current DAAP clients (including official iTunes before iTunes 7.0) will fail to connect to an iTunes 7.0 server, receiving a '403 Forbidden' HTTP error. The iTunes 7.0 authentication traffic analysis seem to indicate that a certificate exchange is performed to calculate the hash sent in the 'Client-DAAP-Validation' header.

As of December 8, 2016, the iTunes 7.0+ DAAP authentication still hasn't been reverse engineered, so no third-party application can stream from servers running iTunes software (from 7.x, all the way up to and including version 11.x).[5]

DAAP clients

Name Platform: Desktop Platform: Portable Platform: Devices/Other Platform: TVs Development status
iOS Music app (formerly iPod app) iOS (by setting: password on Settings, then More>Shared), since iOS 4.3 Native
Amarok Windows, Mac, Linux Active
Banshee Windows, Mac, Linux Active
Crossfire Cross-platform Ajax-based Firefly client, with multiple browser support

Safari (inc. iOS), Nokia, Opera, IE, Chrome

 Active
DAAP Client Android Active
DAAP Media Player Windows Phone 8 Active
Diapente Android Active
FireflyClient Independent (uses Java) Dormant
Get it together Any Java supported platform Dormant
iTunes Windows, Mac iOS Apple TV Native
LimeWire Windows, Mac, Linux Active
One2OhMyGod Any Java supported platform Dormant
Rhythmbox Linux Active
Roku Soundbridge and Radio Roku Dormant
WiFiTunes PocketPC Dormant
Songbird Windows, Mac, Linux (unsupported) Dormant, via plugin for 1.8.0
SoundBox Windows, Mac Active
Silverplay Only Silverlight required Active
Simple DAAP Client iOS Dormant
Winamp with ml_daap plugin Windows Winamp discontinued on 12/20/2013; ml_daap dormant, depends on Apple Bonjour support for Windows
XBMC Windows, Mac, Linux XBMC Live iPad Apple TV (2nd generation) only, and some others Active

DAAP servers

Name Operating system Development status
Linux OS X Microsoft Windows Other
iTunes No Yes Yes No Active
forked-daapd Yes No No FreeBSD Active
Firefly Media Server (mt-daapd) Yes Yes Yes FreeBSD Dormant
Tangerine Yes Yes Yes FreeBSD Dormant
spydaap DAAP server (python) Yes Yes Yes FreeBSD Dormant
FreeNAS and NAS4Free No No No FreeBSD Active
NASLite M2 Yes No No No Active
OpenMediaVault Yes No No No Active
Ampache Yes Yes Yes FreeBSD Active
Rhythmbox Yes No No No Active

See also

Notes and references

  1. ↑ "Unofficial DAAP protocol documentation" by Daniel Garcia, retrieved December 2, 2006
  2. ↑ "Well Known Port Numbers" by IANA, November 30, 2006, retrieved December 2, 2006
  3. ↑ "Apple halts iTunes' Internet sharing ability" by Tony Smith, The Register, May 28, 2003, retrieved August 31, 2006
  4. ↑ "iTunes 4.5 Authentication Cracked". April 29, 2004. Retrieved March 12, 2007.
  5. ↑ "daap with iTunes 7 doesn't work correctly". Launchpad bug tracker. 2006-09-28.
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