Crate typebit 

no_std + alloc download-engine core: BitTorrent v1/v2 (peer wire, DHT, PEX, LSD, uTP, web seeds, UDP/HTTP trackers, magnet, SOCKS5) — plus provable download receipts, a utility scheduler and a disk cache. links::parse_link also parses eD2k / Thunder / QQDL / FlashGet / IPFS / Kad / Baidu / Xunlei-Netdisk links into typed links::DownloadLink values (parsing only — no fetch adapters for those protocols yet, see the README protocol matrix). Transport is injected via platform::Host; crypto is in-tree under crypto.

Re-exports

pub use engine::Engine;

pub use engine::EngineConfig;

pub use engine::EngineEvent;

pub use error::Error;

pub use error::Result;

pub use metainfo::InfoHash;

pub use platform::Host;

pub use platform::LogLevel;

pub use platform::NetAddr;

Modules

bencode

Bencode codec (BEP-3) with strict resource limits, for .torrent metainfo, tracker announce/scrape and DHT KRPC. Exposes a raw-range walker to capture the exact info dict for infohash computation.

bitfield

Compact bitset for piece availability and block accounting.

consts

Protocol constants.

crypto

In-tree cryptography (the engine may only link the four ecosystem crates). Implemented from scratch, no_std, unsafe-free, pinned against standard test vectors:

dht

Kademlia DHT (BEP-5/42): pure no_std KRPC engine — routing table, transactions, announce tokens, iterative lookups. BEP-5 token auth for announce_peer; iterative get_peers/find_node with K-closest pruning.

disk_cache

Write-back disk cache: blocks are buffered and flushed in large, offset-ordered coalesced batches (fewer writes/seeks); a piece hits stable storage before it is verified. Read-through serves seeding reads.

engine

The top-level engine: owns the host, all torrent sessions, the shared disk cache and the DHT, and drives the non-blocking event loop. The host calls Engine::tick on a fixed cadence and drains Engine::take_events.

error

Unified error type for the TypeBit core.

ffiffi

C ABI for the TypeBit engine — the language bridge.

geo

Best-effort IPv4 → country (ISO-3166 alpha-2) lookup for peer rows.

host_stdstd

OS-backed Host for desktop/server builds (feature std).

leech

Anti-leech engine: client fingerprinting, per-peer reputation, reciprocity-aware choke scoring (tit-for-tat), snub handling, corrupt accountability with bans, optimistic unchoke rotation, anti-flap.

links

Unified download-link parsing. parse_link turns every mainstream URL format into a typed DownloadLink (magnet, eD2k, Xunlei, QQDL, FlashGet, IPFS/IPNS, Kad, HTTP(S)/FTP, Baidu/Xunlei Netdisk — Netdisks need host credentials). ContentId gives cross-format content addressing.

lsd

Local Service Discovery (LSD, BEP-14): announce our presence in active swarms to LAN neighbours over UDP multicast, and answer their announces — no internet tracker or DHT needed.

magnet

Magnet URI parsing (BEP-9 / BEP-53).

metainfo

Torrent metainfo: v1 (BEP-3), v2 (BEP-52) and hybrid parsing.

monitoring

Swarm availability monitoring (“the downloader as a measurement probe”): treats the torrent as a time-varying replication graph and estimates content recoverability A(t, B) = Pr[obtain and verify all required pieces within budget B], producing an evidence-backed SwarmReport (JSON via nextjson) as early-warning for drifting content.

peer_id

Peer id generation and client identification.

pex

Peer exchange (BEP-11 / BEP-11.1) — facade over the wire codec (crate::wire::PexMsg): adds swarm-level helpers for compact peer list encoding with flags.

picker

Piece/block picker.

piece

Per-torrent piece/block state tracking: pieces of piece_length bytes (last possibly shorter), each split into 16 KiB blocks. Tracks verified, partially-received, and in-flight block state.

platform

The platform abstraction seam: the engine is written against Host; a concrete implementation (std, Android/Kotlin, iOS/Swift, embedded) only provides ~15 primitives. Transports are non-blocking (Host::tcp_recv returns Error::WouldBlock, tcp_send may take a partial prefix), so one engine drives hundreds of peers from a single thread.

portmap

Port mapping for the listen port: NAT-PMP (RFC 6886) with UPnP IGD (SSDP discovery + SOAP control) fallback. Allocation-bounded codecs plus a time-driven state machine pumped once per tick; transport via the Host seam. NAT-PMP needs no HTTP; UPnP needs Host::http_post/Host::local_ip (a platform may leave them unsupported → clear failure, not guessing). Replies arrive as unicast UDP on the engine socket, routed here by PortMapManager::handle_datagram.

ratelimit

Token-bucket byte rate limiting. One bucket per throttle point: the engine keeps global upload/download buckets, each TorrentSession keeps per-task buckets. 0 = unlimited. Refill from wall time (now_ms) so buckets stay correct at any tick cadence.

receipt

Provable download & availability receipts.

scheduler

Semantic, utility-driven piece scheduler:

session

Per-torrent session: owns peer connections, piece/block bookkeeping, the utility scheduler, tracker/DHT/PEX discovery, metadata fetching (magnet links), receipts and the swarm monitor; talks outward via SessionCtx.

socks

SOCKS5 (RFC 1928) + username/password auth (RFC 1929) transport — the anonymity seam for Tor (SOCKS5h :9050) and I2P (SOCKS :4444). no_std, depends only on crate::platform + crate::error.

state

Session persistence with the ecosystem codecs: binary via rustbinary, human via nextjson, wall-clock via tzcraft::Ticks. The host stores the produced bytes (file, KV store, mobile keychain).

swarm

Peer connection state and wire-level bookkeeping.

tracker

Tracker protocol codecs: HTTP (BEP-3) announce/scrape URL construction and bencoded parsing (compact + dict peer lists); UDP (BEP-15) connect/announce/scrape builders and parsers. Transport is delegated to the crate::platform::Host seam (http_get / udp_send / udp_recv).

trackerlist

Built-in public tracker list (qBittorrent/BitComet compatible fallback), used when a torrent declares no announce URLs and crate::session::SessionConfig::use_default_trackers is set.

utp

BEP-29 uTP — Micro Transport Protocol over UDP, with LEDBAT congestion control (RFC 6817 style): yields bandwidth when the network is busy, fills the pipe when idle. All I/O goes through Host::udp_send, so it runs on every platform. Pure no_std + alloc, zero unsafe.

verify

Piece hash verification, optionally offloaded to a std worker pool so the engine loop keeps pumping I/O while SHA-1 / SHA-256 runs on other cores. Under no_std, VerifyPool is a no-op handle (inline verification). Both paths share the pure verify_piece function, so pooled and inline results are guaranteed identical.

wire

Peer wire protocol (BEP-3) with extensions: BEP-6 fast (have_all/ have_none/suggest/reject/allowed_fast), BEP-10 extended handshake, BEP-9 metadata (ut_metadata), BEP-11 PEX (ut_pex), BEP-52 v2 bit. All codecs are allocation-bounded and reject malformed frames.