Yet another Bittorrent client/library written in C with a BSD license. The client has been intended to be used as a drop-in bittorrent library. The client is in ALPHA and currently has 130+ unit tests covering the code base.

YABTorrent is event based.

Networkfuncs is a set of networking functions that need to be implemented for the required plumbing. Currently networkworkfuncs_libuv.c is a libuv implementation.

See bt.h for documentation.

Below is a description of the key source files:

• yabtorrent.c: main()
• network_adapter_libuv_v0.10.c: Implementation of network stack
• bt_download_manager.c: Key functions for orchestrating the download
• bt_peer_manager.c: Collection of peers
• bt_piece.c: Manage piece data (ie. write/read and progress)
• bt_piece_db.c: Collection of pieces
• bt_blacklist.c: Block peers from sending invalid pieces
• bt_choker_leecher.c: Choker algorithm for leechers
• bt_choker_seeder.c: Choker algorithm for seeders
• bt_diskcache.c: In-memory file layer that manages a LRU cache over another file layer
• bt_diskmem.c: In-memory file layer (for testing only)
• bt_filedumper.c: File layer that writes/reads to disk
• bt_selector_endgame.c: End game piece selection alogrithm
• bt_selector_random.c: Random piece selection alogrithm
• bt_selector_rarestfirst.c: Rarest first piece selection alogrithm
• bt_selector_sequential.c: Sequential piece selection alogrithm

https://github.com/willemt/dogebox - a Bittorrent Sync clone

$git clone https://github.com/willemt/YABTorrent

$cd YABTorrent

$python waf configure

$python waf build

$./bt torrentfile.torrent

1. There aren't any bittorrent clients in C that are licensed under non-copyleft licenses
2. There aren't any lightweight bittorrent C libraries that aim to be integrable outside of their intended use case

If you want to help out with development, please look into the following:

• BEP 5 - DHT Protocol - github.com/willemt/CTrackerClient simply needs to handle the "dht://" schema. github.com/jech/dht can be used to add this functionality.
• BEP 2 - uTorrent transport protocol - you need to create a "networkfuncs_utp.c" source file which implements all the network callbacks. "networkfuncs_utp.c" would simply be a wrapper of github.com/bittorrent/libutp.
• BEP 9 - Extension for Peers to Send Metadata Files
• uTorrent Peer Exchange