Advanced Direct Connect
Template:Advanced Direct Connect Advanced Direct Connect (ADC) is a peer-to-peer file sharing and chat protocol, using the same 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
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
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.
This article compares features and other data about client and server software for Direct Connect, a peer-to-peer file sharing protocol.
Hub software
Direct Connect hubs are central servers to which clients connect, thus the networks are not as decentralized as Gnutella or FastTrack. Hubs provide information about the clients, as well as file-searching and chat abilities. File transfers are done directly between clients, in true peer-to-peer fashion.
Hubs often have special areas of interest. Many have requirements on the total size of the files that their members share (share size), and restrictions on the content and quality of shares. A hub can have any arbitrary rule. Hubs can allow users to register and provide user authentication. The authentication is also in clear text. The hub may choose certain individuals as operators (similar to IRC operators) to enforce said rules if the hub itself cannot.
While not directly supported by the protocol, hub linking software exists. The software allow multiple hubs to be connected, allowing users to share and/or chat with people on the other linked hubs. Direct connect hubs have difficulty scaling, due to the broadcast-centricity of the protocol.
General
| NMDC[9] hub | FOSS | Software license | Active [10] |
Last update[11] (version) |
GUI | CLI | Other | IPv6 support | Programming language | Based on | Notes |
|---|---|---|---|---|---|---|---|---|---|---|---|
| UFOHub | No | Proprietary Freeware |
Yes | 2024-09-05 (10.24.9) |
Yes | No | Yes | Yes | Unknown | ||
| Verlihub | Yes | GNU GPL | Yes | 2023-12-16 (1.5.0.0) |
No | Yes | Unknown | No | C++, Lua, Python, Perl | ||
| PTDCH | Yes | GNU GPL | No | 2009-01-16 (2.1 Alpha 7) |
Yes | Unknown | Unknown | No | Visual Basic, Jscript, VBscript | DDCH | |
| Dtella | Yes | GNU GPL | No | 2015-06-07 (1.2.9)[12] |
No | No | Yes | No | Python | ||
| HeXHub | Yes | Open Software License | No | 2014-03-01 (5.12) |
Yes | Unknown | Unknown | No | Assembly | ||
| Open Direct Connect Hub | Yes | GNU GPL | No | 2014-08-14 (0.8.3) |
No | Unknown | Unknown | No | C, Perl | Available in Debian[13] and OpenWrt[14] | |
| Flexhub | Yes | GNU AGPL | No | 2013-10-22 (Beta 0.2 svn 1469) |
Pending | Yes | Unknown | No | Lua | ||
| PtokaX | Yes | GNU GPL | Yes | 2022-12-29 (0.5.3.0)[15] |
Yes | Yes | Unknown | Yes | C++, Lua | ||
| RusHub | Yes | GNU GPL | No | 2012-06-10 (2.3.10)[16] |
No | Yes | Unknown | Yes | C++, Lua | Verlihub[17] | |
| Eximius[18] | No | Proprietary Freeware |
No | 2007 | Yes | Unknown | Unknown | No | C#, Lua | ||
| DB Hub | Yes | GNU GPL | No | 2008-02-08 (0.451) |
Unknown | Unknown | Unknown | No | Unknown | OpenDCHub | |
| openDCd | Yes | GNU GPL | No | 2002-03-26 (0.5.8) |
Unknown | Unknown | Unknown | No | Unknown | ||
| DDCH DevDirect Connect Hub | Unknown | Unknown | No | 2007-04-15 (?.?.?) |
Yes | No | No | No | Visual Basic, Jscript | ||
| py-dchub | Yes | MIT | No | 2006-02-13 (0.2.4) |
Unknown | Unknown | Unknown | No | Python | ||
| Aquila | Yes | GNU GPL | No | 2015-02-17 (0.1.11-pre4-beta4) |
No | Yes | No | No | C++, Lua | ||
| YnHub | No | Proprietary Freeware |
No | 2016-07-15 (1.0364.126) |
Yes | No | No | No | Delphi | ||
| LamaHub | Yes | GNU GPL | No | 2010-04-25 (0.0.6.3) |
Unknown | Unknown | Unknown | No | C | ||
| DC Sharp Hub | Yes | GNU GPL | No | 2004-09-06 (3.0.4 beta) |
Unknown | Unknown | Unknown | No | C# | ||
| NMDC[9] hub | FOSS | Software license | Active [10] |
Last update[11] (version) |
GUI | CLI | Other | IPv6 support | Programming language | Based on |
Operating system support
| NMDC[9] hub | Windows | Linux | macOS | Other |
|---|---|---|---|---|
| UFOHub | Yes | No | No | No |
| Eximius | Yes | No | No | No |
| PTDCH | Yes | No | No | No |
| Aquila | Yes | Yes | No | No |
| Dtella | Yes | Yes | Yes | No |
| HeXHub | Yes | No | No | No |
| Open Direct Connect Hub | No | Yes | No | OpenWrt |
| Flexhub | Yes | Yes | No | Qnap and Synology NAS Devices |
| openDCd | Yes | Yes | No | No |
| DDCH DevDirect Connect Hub | Yes | No | No | No |
| DBHub | No | Yes | No | No |
| PtokaX | Yes | Yes | Yes | FreeBSD, OpenBSD, NetBSD, Solaris, illumos, Haiku |
| py-dchub | Yes | Yes | Yes | Any Python compatible platform |
| RusHub | Yes | Yes | Yes | FreeBSD, Solaris |
| VerliHub | No | Yes | No | No |
| Yhub | Yes | No | No | No |
| Ynhub | Yes | No | No | No |
| LamaHub | Yes | Yes | Yes | OS/2, OpenBSD, NetBSD, TrueOS, FreeBSD, ZeX/OS, Android[19] |
| DC Sharp Hub | Yes | No | No | No |
| NMDC[9] hub | Windows | Linux | macOS | Other |
Client software
While not mandated by the protocol, most clients send a "tag". This is part of the client's description and display information ranging from client name and version to number of total available slots to if the user is using a proxy server. It was originally added to DC++, due to its ability to be in multiple hubs with the same instance. The information is arbitrary. The original client's file list (a comprehensive list of the files a user shares) was compressed using Huffman's compression algorithm. Newer clients (among them DC++) serve an XML-based list, compressed with bzip2.
General
| NMDC[9] Client | FOSS | Software license | Last update[11] (version) |
Windows | Linux | macOS | Other OS | GUI | CLI | Other UI | Programming language | Based on |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MLDonkey | Yes | GNU GPL | 2020-06-06 (3.1.7-2) |
Yes | Yes | Yes | No | Yes | Yes | WebUI | OCaml, C, assembly | |
| Shareaza | Yes | GNU GPL | 2017-09-18 2.7.10.2 |
Yes | No | No | No | Yes | Unknown | Unknown | C++ | |
| NeoModus Direct Connect | No | Proprietary Freeware |
2004-10-23 2.205 |
Yes | Yes | No | No | Yes | No | No | Visual Basic, C++ | |
| ShakesPeer | Yes | GNU GPL | 2013-06-08 | No | No | Yes | No | Yes | No | No | C | |
| Valknut | Yes | GNU GPL | 2009-02-10 0.4.9 |
No | Yes | No | FreeBSD | Yes | No | No | C++ | |
| DCTC | Yes | GNU GPL | 2004-01-24 0.85.9 |
No | No | Yes | C++ | |||||
| DC# | Yes | GNU GPL | Yes | No | No | No | Yes | No | No | C# | ||
| LDCC | Yes | GNU GPLv2 | 2004-07-15 2.0.7 |
No | Yes | No | No | No | No | Yes | C | |
| DCDM++ | Yes | GNU GPL | 2004-04-04 0.021 |
Yes | No | No | No | Yes | No | No | C++ | DC++ |
| fulDC | Yes | GNU GPL | 2007-04-01 6.79 Beta 8 |
Yes | No | No | No | Yes | No | No | C++ | DC++ |
| RevConnect | Yes | GNU GPL | 2007-08-25 0.674p |
Yes | No | No | No | Yes | No | No | C++ | DC++ |
| CzDC | Yes | GNU GPL | 2011-01-20 0.699 |
Yes | No | No | No | Yes | No | No | C++ | DC++ |
| EiskaltDC++ | Yes | GNU GPL | 2021-03-02 2.4.2 |
No | Yes | Yes | FreeBSD | Yes | No | No | C++ | Valknut |
| microdc2 | Yes | GNU GPL | 2006-12-24 0.15.6 |
No | Yes | Yes | FreeBSD | No | Yes | No | C | |
| NMDC[9] Client | FOSS | Software license | Last update[11] (version) |
Windows | Linux | macOS | Other OS | GUI | CLI | Other UI | Programming language | Based on |
Other software
Hub linking software links hubs' main chat, so that users can see and respond to chat that is in a hub they're not directly connected to. Often used to draw in users to hubs, or make private or small hubs more widely known. Whereas advertising a hub is "frowned upon" and is usually repercussion with floods or denial of service attacks, forming a more or less formal network by means of linking hub chat is a legitimate means for getting free publicity. Some Hub programs are able to support a more advanced form of linking which includes all the normal functions, chat, private messages, search and file transfers between users on different hubs can be supported through hub specific solutions or hub software neutral extensions using scripts/plug-ins.
General
| Other software | Software type | FOSS | Software license | Active[10] |
|---|---|---|---|---|
| jDCBot | General library | Yes | GNU GPL | Yes |
| Net::DirectConnect | General library | Yes | Unknown | Yes |
| FlowLib | General library | Yes | GNU GPL | Yes |
| DC-hublink | Link | Yes | GNU GPL | No |
| Hub-Link | Link | Yes | GNU GPL | No |
| MyIrcDcLinks | Link | Yes | GNU GPL | Yes |
| NetChatLink | Link | Yes | GNU GPL | Yes |
| Kitty | Bot | Yes | GNU GPL | No |
| Other software | Software type | FOSS | Software license | Active[10] |
Operating system support
| Other software | Windows | Linux | macOS | Other |
|---|---|---|---|---|
| jDCBot | Yes | Yes | Yes | Any Java compatible platform |
| Net::DirectConnect | Yes | Yes | Yes | Any Perl compatible platform |
| FlowLib | Yes | Yes | Yes | Any C# compatible platform |
| DC-hublink | Yes | No | No | No |
| Hub-Link | Yes | No | No | No |
| MyIrcDcLinks | Yes | No | No | No |
| NetChatLink | Yes | No | No | Runs under WINE |
| Kitty | Yes | No | No | No |
| Other software | Windows | Linux | macOS | Other |
Interface and programming
| Other software | GUI | CLI | Other | Programming language | Based on |
|---|---|---|---|---|---|
| jDCbot | No | No | No | Java | |
| Net::DirectConnect | No | No | No | Perl | |
| FlowLib | No | No | No | C# | |
| DC-hublink | Yes | No | No | Visual Basic | |
| Hub-Link | Yes | No | No | Visual Basic | |
| MyIrcDcLinks | Yes | No | No | Delphi | |
| NetChatLink | Yes | No | No | Delphi | |
| Kitty | Unknown | Unknown | Unknown | C# | |
| Other software | GUI | CLI | Other | Programming language | Based on |
See also
References
- ^ Fredrik Ullner (2006). "Power + Person = Operator". DC++: Just These Guys, Ya Know? blog. Retrieved 2010-12-13.
{{cite web}}: Unknown parameter|month=ignored (help) - ^ Fredrik Ullner (2007). "The parts of a hub list". DC++: Just These Guys, Ya Know? blog. Retrieved 2010-12-13.
{{cite web}}: Unknown parameter|month=ignored (help) - ^ Fredrik Ullner (2006). "Slots, slots, slots…". DC++: Just These Guys, Ya Know? blog. Retrieved 2010-12-13.
{{cite web}}: Unknown parameter|month=ignored (help) - ^ Fredrik Ullner (2010). "ADC Extensions - NATT - NAT traversal". ADC Project. Retrieved 2010-12-13.
{{cite web}}: Unknown parameter|month=ignored (help) - ^ Fredrik Ullner (2010). "ADC Extensions - ADCS - Symmetrical Encryption in ADC". ADC Project. Retrieved 2010-12-13.
{{cite web}}: Unknown parameter|month=ignored (help) - ^ Fredrik Ullner (2007). "ADC: The run down". DC++: Just These Guys, Ya Know? blog. Retrieved 2010-12-13.
{{cite web}}: Unknown parameter|month=ignored (help) - ^ Jan Vidar Krey (2006). "ADC: Protocol simplicity". Jan Vidar Krey. Retrieved 2006-09-23.
{{cite web}}: Unknown parameter|month=ignored (help) [dead link] - ^ En_Dator (2009). "TLS and Encryption". ADCPortal. Retrieved 2009-03-01.
{{cite web}}: Unknown parameter|month=ignored (help) - ^ a b c d e f Cite error: The named reference
NMDCwas invoked but never defined (see the help page). - ^ a b c d Cite error: The named reference
ActiveProjectswas invoked but never defined (see the help page). - ^ a b c d Cite error: The named reference
DateFormatwas invoked but never defined (see the help page). - ^ "Dtella Labs". dtella.org. Archived from the original on 2012-07-11. Retrieved 30 December 2016.
- ^ "Package: opendchub (0.8.2-2)". debian.org. Archived from the original on 2014-04-16. Retrieved 30 December 2016.
- ^ "Index of /snapshots/trunk/ar71xx/packages/". openwrt. Archived from the original on 2014-04-16. Retrieved 30 December 2016.
- ^ "PtokaX Direct Connect Hub". www.ptokax.org. Archived from the original on 2012-09-07. Retrieved 30 December 2016.
- ^ "RusHub - Browse /RusHub at SourceForge.net". sourceforge.net. Archived from the original on 2012-07-22. Retrieved 30 December 2016.
- ^ "rushhub.org". rushhub. Archived from the original on 2015-06-23. Retrieved 30 December 2016.
- ^ "Eximius". RS2Soft.nl. 8 May 2009. Archived from the original on 8 May 2009. Retrieved 30 December 2016.
- ^ "LamaHub DC++ hubsoft". lamahub.sourceforge.net. Archived from the original on 2012-12-25. Retrieved 30 December 2016.