# aquatic [![CargoBuildAndTest](https://github.com/greatest-ape/aquatic/actions/workflows/cargo-build-and-test.yml/badge.svg)](https://github.com/greatest-ape/aquatic/actions/workflows/cargo-build-and-test.yml) [![Test HTTP, UDP and WSS file transfer](https://github.com/greatest-ape/aquatic/actions/workflows/test-transfer.yml/badge.svg)](https://github.com/greatest-ape/aquatic/actions/workflows/test-transfer.yml) Blazingly fast, multi-threaded BitTorrent tracker written in Rust. Consists of three sub-implementations for different protocols: * `aquatic_udp`: BitTorrent over UDP. Implementation achieves 45% higher throughput than opentracker (see benchmarks below) * `aquatic_http`: BitTorrent over HTTP/TLS (slightly experimental) * `aquatic_ws`: WebTorrent (experimental) ## Copyright and license Copyright (c) 2020-2021 Joakim Frostegård Distributed under Apache 2.0 license (details in `LICENSE` file.) ## Installation prerequisites - Install Rust with [rustup](https://rustup.rs/) (stable is recommended) - Install cmake with your package manager (e.g., `apt-get install cmake`) - On GNU/Linux, also install the OpenSSL components necessary for dynamic linking (e.g., `apt-get install libssl-dev`) - Clone the git repository and refer to the next section. ## Compile and run To compile the master executable for all protocols, run: ```sh ./scripts/build-aquatic.sh ``` To start the tracker for a protocol with default settings, run: ```sh ./target/release/aquatic udp ./target/release/aquatic http ./target/release/aquatic ws ``` To print default settings to standard output, pass the "-p" flag to the binary: ```sh ./target/release/aquatic udp -p ./target/release/aquatic http -p ./target/release/aquatic ws -p ``` Note that the configuration files differ between protocols. To adjust the settings, save the output of the relevant previous command to a file and make your changes. Then run `aquatic` with a "-c" argument pointing to the file, e.g.: ```sh ./target/release/aquatic udp -c "/path/to/aquatic-udp-config.toml" ./target/release/aquatic http -c "/path/to/aquatic-http-config.toml" ./target/release/aquatic ws -c "/path/to/aquatic-ws-config.toml" ``` The configuration file values you will most likely want to adjust are `socket_workers` (number of threads reading from and writing to sockets) and `address` under the `network` section (listening address). This goes for all three protocols. Access control by info hash is supported for all protocols. Relevant part of configuration: ```toml [access_list] mode = 'off' # Change to 'black' (blacklist) or 'white' (whitelist) path = '' # Path to text file with newline-delimited hex-encoded info hashes ``` Some more documentation of configuration file values might be available under `src/lib/config.rs` in crates `aquatic_udp`, `aquatic_http`, `aquatic_ws`. ## Details on implementations ### aquatic_udp: UDP BitTorrent tracker Aims to implements the [UDP BitTorrent protocol](https://libtorrent.org/udp_tracker_protocol.html), except that it: * Doesn't care about IP addresses sent in announce requests. The packet source IP is always used. * Doesn't track of the number of torrent downloads (0 is always sent). Supports IPv4 and IPv6 (BitTorrent UDP protocol doesn't support IPv6 very well, however.) For optimal performance, enable setting of core affinities in configuration. #### Benchmarks [opentracker]: http://erdgeist.org/arts/software/opentracker/ Server responses per second, best result in bold: | workers | aquatic | [opentracker] | |---------|-----------|---------------| | 1 | n/a | __232k__ | | 2 | __309k__ | 293k | | 3 | __597k__ | 397k | | 4 | __603k__ | 481k | | 6 | __757k__ | 587k | | 8 | __850k__ | 431k | | 10 | __826k__ | 165k | | 16 | __785k__ | 139k | Please refer to `documents/aquatic-udp-load-test-2021-08-19.pdf` for more details. #### Alternative implementation using io_uring [io_uring]: https://en.wikipedia.org/wiki/Io_uring [glommio]: https://github.com/DataDog/glommio There is an alternative implementation that utilizes [io_uring] by running on [glommio]. It only runs on Linux and requires a recent kernel (version 5.1 or later). In some cases, it performs even better than the cross-platform implementation. To use it, pass the `with-glommio` feature when building, e.g.: ```sh cargo build -p aquatic_udp --features "with-glommio" --no-default-features ./target/release/aquatic_udp ``` ### aquatic_http: HTTP BitTorrent tracker Aims for compatibility with the HTTP BitTorrent protocol, as described [here](https://wiki.theory.org/index.php/BitTorrentSpecification#Tracker_HTTP.2FHTTPS_Protocol), including TLS and scrape request support. There are some exceptions: * Doesn't track of the number of torrent downloads (0 is always sent). * Doesn't allow full scrapes, i.e. of all registered info hashes `aquatic_http` has not been tested as much as `aquatic_udp` but likely works fine. #### TLS To run over TLS, a pkcs12 file (`.pkx`) is needed. It can be generated from Let's Encrypt certificates as follows, assuming you are in the directory where they are stored: ```sh openssl pkcs12 -export -out identity.pfx -inkey privkey.pem -in cert.pem -certfile fullchain.pem ``` Enter a password when prompted. Then move `identity.pfx` somewhere suitable, and enter the path into the tracker configuration field `tls_pkcs12_path`. Set the password in the field `tls_pkcs12_password` and set `use_tls` to true. ### aquatic_ws: WebTorrent tracker Aims for compatibility with [WebTorrent](https://github.com/webtorrent) clients, including `wss` protocol support (WebSockets over TLS), with some exceptions: * Doesn't track of the number of torrent downloads (0 is always sent). * Doesn't allow full scrapes, i.e. of all registered info hashes For information about running over TLS, please refer to the TLS subsection of the `aquatic_http` section above. #### Benchmarks [wt-tracker]: https://github.com/Novage/wt-tracker [bittorrent-tracker]: https://github.com/webtorrent/bittorrent-tracker The following benchmark is not very realistic, as it simulates a small number of clients, each sending a large number of requests. Nonetheless, I think that it gives a useful indication of relative performance. Server responses per second, best result in bold: | workers | aquatic | [wt-tracker] | [bittorrent-tracker] | |---------|------------|--------------|----------------------| | 1 | n/a | __117k__ | 45k | | 2 | __225k__ | n/a | n/a | | 4 | __627k__ | n/a | n/a | | 6 | __831k__* | n/a | n/a | | 8 | __1209k__* | n/a | n/a | | 10 | __1455k__* | n/a | n/a | | 12 | __1650k__* | n/a | n/a | | 14 | __1804k__* | n/a | n/a | | 16 | __1789k__* | n/a | n/a | \* Using a VPS with 32 vCPUs. The other measurements were made using a 16 vCPU VPS. Please refer to `documents/aquatic-ws-load-test-2021-08-18.pdf` for more details. ## Load testing There are load test binaries for all protocols. They use a CLI structure similar to `aquatic` and support generation and loading of configuration files. To run, first start the tracker that you want to test. Then run the corresponding load test binary: ```sh ./scripts/run-load-test-udp.sh ./scripts/run-load-test-http.sh ./scripts/run-load-test-ws.sh ``` To fairly compare HTTP performance to opentracker, set keepalive to false in `aquatic_http` settings. ## Architectural overview One or more socket workers open sockets, read and parse requests from peers and send them through channels to request workers. The request workers go through the requests, update shared internal tracker state as appropriate and generate responses that are sent back to the socket workers. The responses are then serialized and sent back to the peers. This design means little waiting for locks on internal state occurs, while network work can be efficiently distributed over multiple threads, making use of SO_REUSEPORT setting. ## Trivia The tracker is called aquatic because it thrives under a torrent of bits ;-)