Advanced Direct Connect

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Advanced Direct Connect
Protocol Version: 1.0.3
Extension Version 1.0.7
http://www.adc.sourceforge.net
Protocol
BASE · TIGR · BZIP · ZLIB ·
Extensions
PING · TS · DFAV · UCMD · BLOM · NATT · RF · QP · PFSR · LC · KEYP · SUDP · TYPE · FEED · SEGA · FO · FS · ADCS

Advanced Direct Connect (ADC) is a peer-to-peer file sharing and chat protocol, using the same network topology, concepts and terminology as the Direct Connect (DC) protocol.

ADC is structured around clients that connect to a central hub, where the clients (users) can chat and download files from other clients (users). The hub provides routing between clients for chat, searches and requests for connections. The actual file transfers are between clients.

The protocol itself is split in two parts; a base protocol that every client and hub respectively must follow and extensions that are optional. The protocols allow signalling of protocol features (such as bloom filters), and messages can be constructed to only be routed to those who support that particular feature.

Each hub has their own rules and are commonly governed by hub operators.[1] Hubs may define different capabilities for hub operators. The hubs themselves do not regulate discussion and files, but the hub operators. The hub regulate minimum share and maximum amount of simultaneous hubs; things that are sent by the client, rather than the user.

Lists of hubs [2] exist where a hub's name, description, address and rules are specified. With the hub list, users can choose hubs that are similar according to the user's liking of discussion topics and files.

The peer-to-peer part of the protocol is based on a concept of "slots" [3] (similar to number of open positions for a job). These slots denote the number of people that are allowed to download from a user at any time. The slots are controlled by the user of respective client.

ADC require that all text must be sent in UTF-8, which means that users with different system encoding (say, Russian and Chinese) are able to chat with respective native characters.

The protocol natively supports IPv6.

There are two modes a user can be in: "active" or "passive". Clients in active mode can download from anyone else on the network. Passive mode users can only download from active users. Passive clients will be sent search results through the hub, while active clients will receive the results directly. An active searcher will receive (at most) 10 results per user and a passive searcher will receive (at most) 5 results per user. NAT traversal exist as a protocol extension,[4] which allow passive users to connect to other passive users.

The base protocol does not require encryption, but extensions exist to provide encryption with TLS.[5]

Files in client connections are identified by their hash, most commonly the Tiger Tree Hash. The hash algorithm is negotiated with the hub and used throughout the client-hub session, as well as subsequent client-client connections.

"Advanced Direct Connect" is not officially an acronym for "ADC".[6]

History[edit]

ADC was created to allow an extensible protocol and to address some shortcomings of the DC protocol. It was initiated by Jacek Sieka, under the influence of Jan Vidar Krey's DCTNG draft.[7] The first revision of ADC came in 2004 and the first official version in 2007-12-01.

Protocol[edit]

The ADC protocol is a text-based protocol, where commands and their information are sent in clear text, except during password negotiation. The client-server (as well as client-client, where one acts as a "server") aspect of the protocol stipulates that the client speak first when a connection has been made. For example, when a client connects to a hub's socket, the client is the first to talk to the hub.

The protocol requires that all text must be sent as UTF-8 encoded Unicode, normalized in form C.

There are no port defaults, for hubs or clients.

Hub addresses are in the following form: adc://example.com:411, where 411 is the port.

During hub-client protocol information exchange, the client offers a set of hashes it supports. The hub will select one of these hashes, and that hash will be used throughout the hub-client session. If the hub deems that the client doesn't support an (arbitrary) appropriate hash set, an error is raised.

The global identification scheme is based on the hash set producing two end-hashes, where one of them depends on the output of the other. During hub-client information exchange, the client will send these end-hashes, encoded with base32, which the hub will confirm to match. One of these base32 encoded hashes will be further sent to other clients in the network. The global identification scheme is this last string. The client may change its end-hashes on a hub-to-hub basis.

Each user, during a hub session, is assigned a hash that only lasts that particular session. This hash will be used for all client references in that hub. There is no dependency on nicks.

Each client information notification is incrementally sent.

An incoming request for a client-client connection is linked to an actual connection, with the use of a token.

Searches use a token, as well, to identify each result of a search.

There is no out-of-the-box ability for a client to kick or redirect another client from a hub. The hub, however, can kick and redirect arbitrarily. The hub can also require that all other clients in the hub must terminate their transfers with the kicked/redirected client. If a client is redirected to another hub, the redirecting client must use a referrer, similar to the HTTP referrer. The kicked/redirected client is not required to receive a notification message.

The peer-to-peer part of the protocol is based on a concept of "slots" (similar to number of open positions for a job). These slots denote the number of people that are allowed to download from a user at any time. These slots are controlled by the client. Automatic slot allocation is supported by the protocol.

The token in the client-client connection decides who should be allowed to download first.

Downloads are transported using TCP. Searches can be transported using TCP or UDP.

There are two modes a user can be in: active or passive. Clients in active mode can download from anyone else on the network. Passive mode users can only download from active users. Passive clients will be sent search results through the hub, while active clients will receive the results directly. An active searcher will receive (at most) 10 results per user and a passive searcher will receive (at most) 5 results per user.

An active client has a listening port for TCP and another for UDP, though the ports don't depend on each other.

Protocol delimiters are '\n' and ' ' (space). The character '\' is used as an escape sequence. Allowed escape sequences are "\n" (new line), "\s" (space) and "\\" (backslash).

The protocol allows for extensions such as compression with bzip2 or encryption with TLS.[8] While the protocol does not mandate that these extensions be implemented, hubs may require them.

Advanced Direct Connect is a next-generation peer-to-peer file-sharing protocol. This page compares the features of a number of software implementations of the protocol.[9]

Hub software[edit]

General[edit]

ADC hub FOSS Software license Active Notes
ADCH++ Yes GPL Yes
ADCH++ GUI Yes GPL No
DSHub Yes GPL No
FlexHub Yes AGPL Yes
Luadch Yes MIT License Yes
Nexthub Yes MIT License No
uhub Yes GPL Yes In Debian[10] and OpenWrt[11]
ErlHub Yes GPL ?
Qhub Yes GPL No
Starlet ADC Hub No Proprietary Yes
Starhub No source code available No
RusHub Yes GPL Yes
ADC hub FOSS Software license Active

.[12]

Operating system support[edit]

ADC hub Windows Linux OS X Other
ADCH++ Yes Yes No No
ADCH++ GUI Yes Yes No Any Python enabled platform
DSHub Yes Yes Yes Any Java enabled platform
FlexHub Yes Yes No No
Luadch Yes Yes Yes BSD
Nexthub Yes ? No Any C# enabled platform
uhub Yes Yes Yes BSD, Haiku, OpenWrt, Solaris
Erlhub Yes Yes Yes Any Erlang enabled platform
Qhub ? ? ? ?
Starlet ADC Hub No No No OpenVMS
Starhub Yes Yes Yes Any Java enabled platform
RusHub Yes Yes Yes FreeBSD, Solaris
ADC hub Windows Linux OS X Other

.[13]

Interface and programming[edit]

ADC hub GUI
CLI
Other
Programming language
Based on
ADCH++ No Yes ? C++, Lua, Python, Ruby
ADCH++ GUI Yes No ? C++, Python ADCH++
DSHub Yes Yes ? Java, Python
FlexHub Planned Yes ? Lua
Luadch No Yes ? Lua
Nexthub Yes No No C-Sharp
uhub No Yes ? C
Erlhub ? ? ? Erlang
Qhub ? ? ? ?
Starlet ADC Hub No Yes No C
StarHub Yes ? ? Java
RusHub No Yes No C++
ADC hub GUI CLI Other Programming language Based on

[14]

Features[edit]

ADC hub Encryption IPv6 Plugin Hash algorithms Bloom filter ADC support Other
ADCH++ Yes Yes Lua, Python, Ruby Tiger tree hash Yes TIGR, PING, ADCS
ADCH++ GUI Yes No Python Tiger tree hash Yes TIGR, PING, ADCS
DSHub Yes No Java, Python Tiger tree hash No TIGR, PING, ADCS
FLexHub Linux only No No Tiger tree hash No TIGR, PING, ADCS
Luadch Yes No Lua Tiger tree hash No TIGR, PING, ADCS
Nexthub Yes No C# Tiger tree hash No TIGR, ADCS
uhub Yes Yes C Tiger tree hash No TIGR, PING, ADCS
Qhub ? ? ? Tiger tree hash No TIGR
Starlet ADC Hub No No No Tiger tree hash No TIGR
Starhub ? ? ? Tiger tree hash No TIGR
RusHub No ? No Tiger tree hash No TIGR
ADC hub Encryption IPv6 Plugin Hash algorithms Bloom filter ADC support Other

.[15]

Client software[edit]

General[edit]

ADC client FOSS Software license Active
AirDC++ Yes GNU GPL Yes
AirDC++ nano Yes GNU GPL Yes
ApexDC++ Yes GNU GPL Yes
DC++ Yes GNU GPL Yes
jucy Yes BSD Yes
LinuxDC++ Yes GNU GPL Yes
EiskaltDC++ Yes GNU GPL Yes
FlylinkDC++ Yes GNU GPL Yes
RSX++ Yes GNU GPL No
TkDC++ Yes GNU GPL No
StrongDC++ Yes GNU GPL Yes
ncdc Yes MIT Yes
ADC client FOSS Software license Active

Operating system support[edit]

ADC client Windows Linux OS X BSD Haiku
AirDC++ Yes No No No No
AirDC++ nano No Yes Yes ? ?
ApexDC++ Yes No No No No
DC++ Yes No No No No
jucy Yes Yes Yes No No
LinuxDC++ No Yes No Yes No
EiskaltDC++ Yes Yes Yes Yes Yes
FlylinkDC++ Yes No No No No
RSX++ Yes No No No No
TKDC++ Yes No No No No
StrongDC++ Yes No No No No
ncdc No Yes Yes Yes ?
ADC client Windows Linux OS X BSD Haiku

.[16]

Interface and programming[edit]

ADC client GUI CLI Other Programming language Based on
AirDC++ Yes No No C++ StrongDC++
AirDC++ nano No Yes No C++ AirDC++,nanodc
ApexDC++ Yes No No C++, Lua StrongDC++
DC++ Yes No No C++
Jucy Yes No No Java
LinuxDC++ Yes No No C++ DC++
EiskaltDC++ Yes Yes JSON-RPC C++, Lua DC++, FreeDC++
FlylinkDC++ Yes No WebUI C++ StrongDC++, DC++, ApexDC speed mode
RSX++ Yes No No C++, Lua StrongDC++
TKDC++ Yes No No C++, Lua StrongDC++, DC++
StrongDC++ Yes No No C++ DC++
ncdc No Yes No C
ADC client GUI CLI Other Programming language Based on

.[17]

Features[edit]

ADC client Magnet URI UPnP NAT traversal DHT Encryption IPv6 Plugin Proxy Hash algorithms Protocol support NMDC compatible Other
AirDC++ Yes Yes Yes No Yes Yes No Yes Tiger tree hash TIGR, ADCS, UCMD,NATT, SEGA, PFSR, KEYP, PBD1, UBN1, MCN1, BLOM, SUDP, FO, QP, HBRI, ASCH Yes
AirDC++ nano No Yes Yes No Yes Yes No Yes Tiger tree hash Inherits from AirDC++ Yes
ApexDC++ Yes Yes Yes Yes Yes No C++, Lua Yes Tiger tree hash Inherits from StrongDC++ Yes
DC++ Yes Yes Yes No Yes Yes C++, Lua Yes Tiger tree hash TIGR, ADCS, UCMD, BLOM, NATT, SEGA Yes
jucy Yes Yes No No Yes Yes Eclipse RCP Yes Tiger tree hash TIGR, ADCS, KEYP, SUDP, BLOM, UCMD Yes
LinuxDC++ Yes Yes No No Yes No No Yes Tiger tree hash Inherits from DC++ Yes
EiskaltDC++ Yes Yes Yes Yes Yes No Lua, QtScript, QML Yes Tiger tree hash TIGR, ADCS, UCMD, BLOM, NATT, SEGA, PFSR, KEYP, FS Yes
FlylinkDC++ Yes Yes Yes Yes Yes No No Yes Tiger tree hash Inherits from StrongDC++ Yes
RSX++ Yes Yes No Yes Yes No C++, Lua Yes Tiger tree hash Inherits from StrongDC++ Yes
TKDC++ Yes Yes Yes No Yes No C++, Lua Yes Tiger tree hash TIGR, ADCS, UCMD, BLOM, NATT, PFSR, SEGA Yes
StrongDC++ Yes Yes Yes Yes Yes No No Yes Tiger tree hash TIGR, ADCS, UCMD, BLOM, NATT, PFSR, QP, SEGA Yes
ncdc No No No No Yes Yes No No Tiger tree hash TIGR, ADCS, KEYP, SUDP Yes
ADC client Magnet URI UPnP NAT traversal DHT Encryption IPv6 Plugin Proxy Hash algorithms Protocol support NMDC compatible Other

.[18]

Other software[edit]

General[edit]

Other software Software type FOSS Software license Active
ADCCore General library Yes GNU GPL Yes
DCBouncer Relay Yes GNU GPL Yes
DC-Hublink Hub linker Yes GNU GPL No
DCWatch Hub operator helper Yes GNU GPL No
Embla General library Yes GNU GPL ?
FlowLib General library Yes GNU GPL Yes
NetChatLink Hub linker Yes GNU GPL Yes
SerieBot SerieBot Yes GNU GPL Yes
Other software Software type FOSS Software license Active

.[19]

Operating system support[edit]

Other software Windows Linux OS X Other
ADCCore Yes ? ? Any .NET4 enabled platform
DCBouncer Yes Yes No No
DC-Hublink Yes No No No
DCWatch Yes Yes No No
Embla Yes Yes Yes Any Java enabled platform
FlowLib Yes Yes Yes Any C# enabled platform
NetChatLink Yes No No Runs under Wine
SerieBot Yes Yes Yes Any C# enabled platform
Other software Windows Linux OS X Other

.[20]

Interface and programming[edit]

Other software GUI CLI Other Programming language Based on
ADCCore No No No C# CoreDC
DCBouncer No Yes No C++
DC-Hublink Yes No No Visual Basic
DCWatch No Yes No Java, Lua Embla
Embla No No No Java
FlowLib No No No C#
NetChatLink Yes No No Object Pascal (Delphi)
ADC hub GUI CLI Other Programming language Based on

Features[edit]

Other software Encryption IPv6 Plugin, extendable Hash algorithms ADC support Other
ADCCore Yes ? Yes Tiger tree hash TIGR, ADCS
DCBouncer Yes No No Tiger tree hash Any clients, hubs
DC-Hublink No No No Tiger tree hash TIGR
DCWatch Yes ? Java, Lua Tiger tree hash TIGR, ADCS
Embla Yes ? Yes Tiger tree hash TIGR
FlowLib Yes ? Yes Tiger tree hash TIGR
NetChatLink No No No Tiger tree hash TIGR
Other software Encryption IPv6 Plugin, extendable Hash algorithms ADC support Other

.[21]

References[edit]

  1. ^ Fredrik Ullner (March 2006). "Power + Person = Operator". DC++: Just These Guys, Ya Know? blog. Retrieved 2010-12-13. 
  2. ^ Fredrik Ullner (January 2007). "The parts of a hub list". DC++: Just These Guys, Ya Know? blog. Retrieved 2010-12-13. 
  3. ^ Fredrik Ullner (March 2006). "Slots, slots, slots…". DC++: Just These Guys, Ya Know? blog. Retrieved 2010-12-13. 
  4. ^ Fredrik Ullner (December 2010). "ADC Extensions - NATT - NAT traversal". ADC Project. Retrieved 2010-12-13. 
  5. ^ Fredrik Ullner (December 2010). "ADC Extensions - ADCS - Symmetrical Encryption in ADC". ADC Project. Retrieved 2010-12-13. 
  6. ^ Fredrik Ullner (March 2007). "ADC: The run down". DC++: Just These Guys, Ya Know? blog. Retrieved 2010-12-13. 
  7. ^ Jan Vidar Krey (August 2006). "ADC: Protocol simplicity". Jan Vidar Krey. Retrieved 2006-09-23. [dead link]
  8. ^ En_Dator (March 2009). "TLS and Encryption". ADCPortal. Retrieved 2009-03-01. 
  9. ^ "Comparison Of ADC Software". http://www.mindmap.0rg.p. Retrieved 8 March 2013. 
  10. ^ https://packages.debian.org/sid/uhub
  11. ^ http://downloads.openwrt.org/snapshots/trunk/ar71xx/packages/
  12. ^ "Comparison Of ADC Software". http://www.mindmap.0rg.p. Retrieved 8 March 2013. 
  13. ^ "Comparison Of ADC Software". http://www.mindmap.0rg.p. Retrieved 8 March 2013. 
  14. ^ "Comparison Of ADC Software". http://www.mindmap.0rg.p. Retrieved 8 March 2013. 
  15. ^ "Comparison Of ADC Software". http://www.mindmap.0rg.p. Retrieved 8 March 2013. 
  16. ^ "Comparison Of ADC Software". http://www.mindmap.0rg.p. Retrieved 8 March 2013. 
  17. ^ "Comparison Of ADC Software". http://www.mindmap.0rg.p. Retrieved 8 March 2013. 
  18. ^ "Comparison Of ADC Software". http://www.mindmap.0rg.p. Retrieved 8 March 2013. 
  19. ^ "Comparison Of ADC Software". http://www.mindmap.0rg.p. Retrieved 8 March 2013. 
  20. ^ "Comparison Of ADC Software". http://www.mindmap.0rg.p. Retrieved 8 March 2013. 
  21. ^ "Comparison Of ADC Software". http://www.mindmap.0rg.p. Retrieved 8 March 2013. 

See also[edit]


References[edit]


External links[edit]