quiche is an implementation of the QUIC transport protocol and HTTP/3 as specified by the IETF. It provides a low level API for processing QUIC packets and handling connection state. The application is responsible for providing I/O (e.g. sockets handling) as well as an event loop with support for timers.
For more information on how quiche came about and some insights into its design you can read a post on Cloudflare's blog that goes into some more detail.
quiche powers Cloudflare edge network's HTTP/3 support. The cloudflare-quic.com website can be used for testing and experimentation.
quiche can be integrated into curl to provide support for HTTP/3.
quiche can be integrated into NGINX using an unofficial patch to provide support for HTTP/3.
Before diving into the quiche API, here are a few examples on how to use the quiche tools provided as part of the quiche-apps crate.
After cloning the project according to the command mentioned in the building section, the client can be run as follows:
$ cargo run --bin quiche-client -- https://cloudflare-quic.com/
while the server can be run as follows:
$ cargo run --bin quiche-server -- --cert apps/src/bin/cert.crt --key apps/src/bin/cert.key
(note that the certificate provided is self-signed and should not be used in production)
Use the --help
command-line flag to get a more detailed description of each tool's options.
The first step in establishing a QUIC connection using quiche is creating a configuration object:
let config = quiche::Config::new(quiche::PROTOCOL_VERSION)?;
This is shared among multiple connections and can be used to configure a QUIC endpoint.
On the client-side the connect()
utility function can be used to create a new connection, while accept()
is for servers:
// Client connection. let conn = quiche::connect(Some(&server_name), &scid, &mut config)?; // Server connection. let conn = quiche::accept(&scid, None, &mut config)?;
Using the connection's recv()
method the application can process incoming packets that belong to that connection from the network:
loop { let (read, from) = socket.recv_from(&mut buf).unwrap(); let recv_info = quiche::RecvInfo { from }; let read = match conn.recv(&mut buf[..read], recv_info) { Ok(v) => v, Err(e) => { // An error occurred, handle it. break; }, }; }
Outgoing packet are generated using the connection's send()
method instead:
loop { let (write, send_info) = match conn.send(&mut out) { Ok(v) => v, Err(quiche::Error::Done) => { // Done writing. break; }, Err(e) => { // An error occurred, handle it. break; }, }; socket.send_to(&out[..write], &send_info.to).unwrap(); }
When packets are sent, the application is responsible for maintaining a timer to react to time-based connection events. The timer expiration can be obtained using the connection's timeout()
method.
let timeout = conn.timeout();
The application is responsible for providing a timer implementation, which can be specific to the operating system or networking framework used. When a timer expires, the connection's on_timeout()
method should be called, after which additional packets might need to be sent on the network:
// Timeout expired, handle it. conn.on_timeout(); // Send more packets as needed after timeout. loop { let (write, send_info) = match conn.send(&mut out) { Ok(v) => v, Err(quiche::Error::Done) => { // Done writing. break; }, Err(e) => { // An error occurred, handle it. break; }, }; socket.send_to(&out[..write], &send_info.to).unwrap(); }
It is recommended that applications pace sending of outgoing packets to avoid creating packet bursts that could cause short-term congestion and losses in the network.
quiche exposes pacing hints for outgoing packets through the [at
] field of the [SendInfo
] structure that is returned by the send()
method. This field represents the time when a specific packet should be sent into the network.
Applications can use these hints by artificially delaying the sending of packets through platform-specific mechanisms (such as the SO_TXTIME
socket option on Linux), or custom methods (for example by using user-space timers).
After some back and forth, the connection will complete its handshake and will be ready for sending or receiving application data.
Data can be sent on a stream by using the stream_send()
method:
if conn.is_established() { // Handshake completed, send some data on stream 0. conn.stream_send(0, b"hello", true)?; }
The application can check whether there are any readable streams by using the connection's readable()
method, which returns an iterator over all the streams that have outstanding data to read.
The stream_recv()
method can then be used to retrieve the application data from the readable stream:
if conn.is_established() { // Iterate over readable streams. for stream_id in conn.readable() { // Stream is readable, read until there's no more data. while let Ok((read, fin)) = conn.stream_recv(stream_id, &mut buf) { println!("Got {} bytes on stream {}", read, stream_id); } } }
The quiche HTTP/3 module provides a high level API for sending and receiving HTTP requests and responses on top of the QUIC transport protocol.
Have a look at the [quiche/examples/] directory for more complete examples on how to use the quiche API, including examples on how to use quiche in C/C++ applications (see below for more information).
quiche exposes a thin C API on top of the Rust API that can be used to more easily integrate quiche into C/C++ applications (as well as in other languages that allow calling C APIs via some form of FFI). The C API follows the same design of the Rust one, modulo the constraints imposed by the C language itself.
When running cargo build
, a static library called libquiche.a
will be built automatically alongside the Rust one. This is fully stand-alone and can be linked directly into C/C++ applications.
Note that in order to enable the FFI API, the ffi
feature must be enabled (it is disabled by default), by passing --features ffi
to cargo
.
quiche requires Rust 1.54 or later to build. The latest stable Rust release can be installed using rustup.
Once the Rust build environment is setup, the quiche source code can be fetched using git:
$ git clone --recursive https://github.com/cloudflare/quiche
and then built using cargo:
$ cargo build --examples
cargo can also be used to run the testsuite:
$ cargo test
Note that BoringSSL, which is used to implement QUIC's cryptographic handshake based on TLS, needs to be built and linked to quiche. This is done automatically when building quiche using cargo, but requires the cmake
command to be available during the build process. On Windows you also need NASM. The official BoringSSL documentation has more details.
In alternative you can use your own custom build of BoringSSL by configuring the BoringSSL directory with the QUICHE_BSSL_PATH
environment variable:
$ QUICHE_BSSL_PATH="/path/to/boringssl" cargo build --examples
Building quiche for Android (NDK version 19 or higher, 21 recommended), can be done using cargo-ndk (v2.0 or later).
First the Android NDK needs to be installed, either using Android Studio or directly, and the ANDROID_NDK_HOME
environment variable needs to be set to the NDK installation path, e.g.:
$ export ANDROID_NDK_HOME=/usr/local/share/android-ndk
Then the Rust toolchain for the Android architectures needed can be installed as follows:
$ rustup target add aarch64-linux-android armv7-linux-androideabi i686-linux-android x86_64-linux-android
Note that the minimum API level is 21 for all target architectures.
cargo-ndk (v2.0 or later) also needs to be installed:
$ cargo install cargo-ndk
Finally the quiche library can be built using the following procedure. Note that the -t <architecture>
and -p <NDK version>
options are mandatory.
$ cargo ndk -t arm64-v8a -p 21 -- build --features ffi
See build_android_ndk19.sh for more information.
To build quiche for iOS, you need the following:
$ xcode-select --install
$ rustup target add aarch64-apple-ios x86_64-apple-ios
cargo-lipo
:$ cargo install cargo-lipo
To build libquiche, run the following command:
$ cargo lipo --features ffi
or
$ cargo lipo --features ffi --release
iOS build is tested in Xcode 10.1 and Xcode 11.2.
In order to build the Docker images, simply run the following command:
$ make docker-build
You can find the quiche Docker images on the following Docker Hub repositories:
The latest
tag will be updated whenever quiche master branch updates.
cloudflare/quiche
Provides a server and client installed in /usr/local/bin.
cloudflare/quiche-qns
Provides the script to test quiche within the quic-interop-runner.
Copyright (C) 2018-2019, Cloudflare, Inc.
See COPYING for the license.