crates/quiche/README.md

![quiche](quiche.svg)

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[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]: https://docs.quic.tech/quiche/
[ietf]: https://quicwg.org/
[post]: https://blog.cloudflare.com/enjoy-a-slice-of-quic-and-rust/

Who uses quiche?
----------------

### Cloudflare

quiche powers Cloudflare edge network's [HTTP/3 support][cloudflare-http3]. The
[cloudflare-quic.com](https://cloudflare-quic.com) website can be used for
testing and experimentation.

### curl

quiche can be [integrated into curl][curl-http3] to provide support for HTTP/3.

### NGINX (unofficial)

quiche can be [integrated into NGINX][nginx-http3] using an unofficial patch to
provide support for HTTP/3.

[cloudflare-http3]: https://blog.cloudflare.com/http3-the-past-present-and-future/
[curl-http3]: https://github.com/curl/curl/blob/master/docs/HTTP3.md#quiche-version
[nginx-http3]: https://github.com/cloudflare/quiche/tree/master/extras/nginx

Getting Started
---------------

### Command-line apps

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](tools/apps/) crate.

After cloning the project according to the command mentioned in the [building](#building) section, the client can be run as follows:

```bash
 $ cargo run --manifest-path=tools/apps/Cargo.toml --bin quiche-client -- https://cloudflare-quic.com/
```

while the server can be run as follows:

```bash
 $ cargo run --manifest-path=tools/apps/Cargo.toml --bin quiche-server -- \
      --cert tools/apps/src/bin/cert.crt \
      --key tools/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.

### Connection setup

The first step in establishing a QUIC connection using quiche is creating a
configuration object:

```rust
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:

```rust
// Client connection.
let conn = quiche::connect(Some(&server_name), &scid, &mut config)?;

// Server connection.
let conn = quiche::accept(&scid, None, &mut config)?;
```

### Handling incoming packets

Using the connection's [`recv()`] method the application can process
incoming packets that belong to that connection from the network:

```rust
loop {
    let read = socket.recv(&mut buf).unwrap();

    let read = match conn.recv(&mut buf[..read]) {
        Ok(v) => v,

        Err(e) => {
            // An error occurred, handle it.
            break;
        },
    };
}
```

### Generating outgoing packets

Outgoing packet are generated using the connection's [`send()`] method
instead:

```rust
loop {
    let write = 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(&out[..write]).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.

```rust
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:

```rust
// Timeout expired, handle it.
conn.on_timeout();

// Send more packets as needed after timeout.
loop {
    let write = 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(&out[..write]).unwrap();
}
```

### Sending and receiving stream data

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:

```rust
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:

```rust
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);
        }
    }
}
```

### HTTP/3

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.

[`connect()`]: https://docs.quic.tech/quiche/fn.connect.html
[`accept()`]: https://docs.quic.tech/quiche/fn.accept.html
[`recv()`]: https://docs.quic.tech/quiche/struct.Connection.html#method.recv
[`send()`]: https://docs.quic.tech/quiche/struct.Connection.html#method.send
[`timeout()`]: https://docs.quic.tech/quiche/struct.Connection.html#method.timeout
[`on_timeout()`]: https://docs.quic.tech/quiche/struct.Connection.html#method.on_timeout
[`stream_send()`]: https://docs.quic.tech/quiche/struct.Connection.html#method.stream_send
[`readable()`]: https://docs.quic.tech/quiche/struct.Connection.html#method.readable
[`stream_recv()`]: https://docs.quic.tech/quiche/struct.Connection.html#method.stream_recv
[HTTP/3 module]: https://docs.quic.tech/quiche/h3/index.html

Have a look at the [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).

[examples/]: examples/

Calling quiche from C/C++
-------------------------

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``.

[thin C API]: https://github.com/cloudflare/quiche/blob/master/include/quiche.h

Building
--------

quiche requires Rust 1.50 or later to build. The latest stable Rust release can
be installed using [rustup](https://rustup.rs/).

Once the Rust build environment is setup, the quiche source code can be fetched
using git:

```bash
 $ git clone --recursive https://github.com/cloudflare/quiche
```

and then built using cargo:

```bash
 $ cargo build --examples
```

cargo can also be used to run the testsuite:

```bash
 $ 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](https://www.nasm.us/). The [official BoringSSL
documentation](https://github.com/google/boringssl/blob/master/BUILDING.md) 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:

```bash
 $ QUICHE_BSSL_PATH="/path/to/boringssl" cargo build --examples
```

[BoringSSL]: https://boringssl.googlesource.com/boringssl/

### Building for Android

To build quiche for Android, you need the following:

- Install the [Android NDK] (13b or higher), using Android Studio or directly.
- Set `ANDROID_NDK_HOME` environment variable to NDK path, e.g.

```bash
 $ export ANDROID_NDK_HOME=/usr/local/share/android-ndk
```

- Install the Rust toolchain for Android architectures needed:

```bash
 $ rustup target add aarch64-linux-android arm-linux-androideabi armv7-linux-androideabi i686-linux-android x86_64-linux-android
```

Note that the minimum API level is 21 for all target architectures.

Depending on the NDK version used, you can take one of the following procedures:

[Android NDK]: https://developer.android.com/ndk

#### NDK version >= 19

For NDK version 19 or higher (21 recommended), you can build in a simpler
way using [cargo-ndk]. You need to install [cargo-ndk] (v2.0 or later) first.

```bash
 $ cargo install cargo-ndk
```

You can build the quiche library using the following procedure. Note that
`-t <architecture>` and `-p <NDK version>` are mandatory.

```bash
 $ cargo ndk -t arm64-v8a -p 21 -- build --features ffi
```

See [build_android_ndk19.sh] for more information.

Note that building with NDK version 18 appears to be broken.

[cargo-ndk]: https://docs.rs/crate/cargo-ndk
[build_android_ndk19.sh]: https://github.com/cloudflare/quiche/blob/master/tools/android/build_android_ndk19.sh

#### NDK version < 18

If you need to use NDK version < 18 (gcc), you can build quiche in the following way.

To prepare the cross-compiling toolchain, run the following command:

```bash
 $ tools/android/setup_android.sh
```

It will create a standalone toolchain for arm64/arm/x86 architectures under the
`$TOOLCHAIN_DIR/arch` directory. If you didn't set `TOOLCHAIN_DIR` environment
variable, the current directory will be used.

After it run successfully, run the following script to build libquiche:

```bash
 $ tools/android/build_android.sh --features ndk-old-gcc
```

It will build binaries for aarch64, armv7 and i686. You can pass parameters to
this script for cargo build. For example if you want to build a release binary
with verbose logs, do the following:

```bash
 $ tools/android/build_android.sh --features ndk-old-gcc --release -vv
```

### Building for iOS

To build quiche for iOS, you need the following:

- Install Xcode command-line tools. You can install them with Xcode or with the
  following command:

```bash
 $ xcode-select --install
```

- Install the Rust toolchain for iOS architectures:

```bash
 $ rustup target add aarch64-apple-ios x86_64-apple-ios
```

- Install `cargo-lipo`:

```bash
 $ cargo install cargo-lipo
```

To build libquiche, run the following command:

```bash
 $ cargo lipo --features ffi
```

or

```bash
 $ cargo lipo --features ffi --release
```

iOS build is tested in Xcode 10.1 and Xcode 11.2.

### Building Docker images

In order to build the Docker images, simply run the following command:

```bash
 $ make docker-build
```

You can find the quiche Docker images on the following Docker Hub repositories:

- [cloudflare/quiche](https://hub.docker.com/repository/docker/cloudflare/quiche)
- [cloudflare/quiche-qns](https://hub.docker.com/repository/docker/cloudflare/quiche-qns)

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](https://github.com/marten-seemann/quic-interop-runner).

Copyright
---------

Copyright (C) 2018-2019, Cloudflare, Inc.

See [COPYING] for the license.

[COPYING]: https://github.com/cloudflare/quiche/tree/master/COPYING