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// Copyright 2023 Divy Srivastava <dj.srivastava23@gmail.com>
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//! _fastwebsockets_ is a minimal, fast WebSocket server implementation.
//!
//! [https://github.com/denoland/fastwebsockets](https://github.com/denoland/fastwebsockets)
//!
//! Passes the _Autobahn|TestSuite_ and fuzzed with LLVM's _libfuzzer_.
//!
//! You can use it as a raw websocket frame parser and deal with spec compliance yourself, or you can use it as a full-fledged websocket server.
//!
//! # Example
//!
//! ```
//! use tokio::net::TcpStream;
//! use fastwebsockets::{WebSocket, OpCode, Role};
//! use anyhow::Result;
//!
//! async fn handle(
//! socket: TcpStream,
//! ) -> Result<()> {
//! let mut ws = WebSocket::after_handshake(socket, Role::Server);
//! ws.set_writev(false);
//! ws.set_auto_close(true);
//! ws.set_auto_pong(true);
//!
//! loop {
//! let frame = ws.read_frame().await?;
//! match frame.opcode {
//! OpCode::Close => break,
//! OpCode::Text | OpCode::Binary => {
//! ws.write_frame(frame).await?;
//! }
//! _ => {}
//! }
//! }
//! Ok(())
//! }
//! ```
//!
//! ## Fragmentation
//!
//! By default, fastwebsockets will give the application raw frames with FIN set. Other
//! crates like tungstenite which will give you a single message with all the frames
//! concatenated.
//!
//! For concanated frames, use `FragmentCollector`:
//! ```
//! use fastwebsockets::{FragmentCollector, WebSocket, Role};
//! use tokio::net::TcpStream;
//! use anyhow::Result;
//!
//! async fn handle(
//! socket: TcpStream,
//! ) -> Result<()> {
//! let mut ws = WebSocket::after_handshake(socket, Role::Server);
//! let mut ws = FragmentCollector::new(ws);
//! let incoming = ws.read_frame().await?;
//! // Always returns full messages
//! assert!(incoming.fin);
//! Ok(())
//! }
//! ```
//!
//! _permessage-deflate is not supported yet._
//!
//! ## HTTP Upgrades
//!
//! Enable the `upgrade` feature to do server-side upgrades and client-side
//! handshakes.
//!
//! This feature is powered by [hyper](https://docs.rs/hyper).
//!
//! ```
//! use fastwebsockets::upgrade::upgrade;
//! use http_body_util::Empty;
//! use hyper::{Request, body::{Incoming, Bytes}, Response};
//! use anyhow::Result;
//!
//! async fn server_upgrade(
//! mut req: Request<Incoming>,
//! ) -> Result<Response<Empty<Bytes>>> {
//! let (response, fut) = upgrade(&mut req)?;
//!
//! tokio::spawn(async move {
//! let ws = fut.await;
//! // Do something with the websocket
//! });
//!
//! Ok(response)
//! }
//! ```
//!
//! Use the `handshake` module for client-side handshakes.
//!
//! ```
//! use fastwebsockets::handshake;
//! use fastwebsockets::FragmentCollector;
//! use hyper::{Request, body::Bytes, upgrade::Upgraded, header::{UPGRADE, CONNECTION}};
//! use http_body_util::Empty;
//! use hyper_util::rt::TokioIo;
//! use tokio::net::TcpStream;
//! use std::future::Future;
//! use anyhow::Result;
//!
//! async fn connect() -> Result<FragmentCollector<TokioIo<Upgraded>>> {
//! let stream = TcpStream::connect("localhost:9001").await?;
//!
//! let req = Request::builder()
//! .method("GET")
//! .uri("http://localhost:9001/")
//! .header("Host", "localhost:9001")
//! .header(UPGRADE, "websocket")
//! .header(CONNECTION, "upgrade")
//! .header(
//! "Sec-WebSocket-Key",
//! fastwebsockets::handshake::generate_key(),
//! )
//! .header("Sec-WebSocket-Version", "13")
//! .body(Empty::<Bytes>::new())?;
//!
//! let (ws, _) = handshake::client(&SpawnExecutor, req, stream).await?;
//! Ok(FragmentCollector::new(ws))
//! }
//!
//! // Tie hyper's executor to tokio runtime
//! struct SpawnExecutor;
//!
//! impl<Fut> hyper::rt::Executor<Fut> for SpawnExecutor
//! where
//! Fut: Future + Send + 'static,
//! Fut::Output: Send + 'static,
//! {
//! fn execute(&self, fut: Fut) {
//! tokio::task::spawn(fut);
//! }
//! }
//! ```
#![cfg_attr(docsrs, feature(doc_cfg))]
mod close;
mod error;
mod fragment;
mod frame;
/// Client handshake.
#[cfg(feature = "upgrade")]
#[cfg_attr(docsrs, doc(cfg(feature = "upgrade")))]
pub mod handshake;
mod mask;
/// HTTP upgrades.
#[cfg(feature = "upgrade")]
#[cfg_attr(docsrs, doc(cfg(feature = "upgrade")))]
pub mod upgrade;
use bytes::Buf;
use bytes::BytesMut;
#[cfg(feature = "unstable-split")]
use std::future::Future;
use tokio::io::AsyncRead;
use tokio::io::AsyncReadExt;
use tokio::io::AsyncWrite;
use tokio::io::AsyncWriteExt;
pub use crate::close::CloseCode;
pub use crate::error::WebSocketError;
pub use crate::fragment::FragmentCollector;
#[cfg(feature = "unstable-split")]
pub use crate::fragment::FragmentCollectorRead;
pub use crate::frame::Frame;
pub use crate::frame::OpCode;
pub use crate::frame::Payload;
pub use crate::mask::unmask;
#[derive(Copy, Clone, PartialEq)]
pub enum Role {
Server,
Client,
}
pub(crate) struct WriteHalf {
role: Role,
closed: bool,
vectored: bool,
auto_apply_mask: bool,
writev_threshold: usize,
write_buffer: Vec<u8>,
}
pub(crate) struct ReadHalf {
role: Role,
auto_apply_mask: bool,
auto_close: bool,
auto_pong: bool,
writev_threshold: usize,
max_message_size: usize,
buffer: BytesMut,
}
#[cfg(feature = "unstable-split")]
pub struct WebSocketRead<S> {
stream: S,
read_half: ReadHalf,
}
#[cfg(feature = "unstable-split")]
pub struct WebSocketWrite<S> {
stream: S,
write_half: WriteHalf,
}
#[cfg(feature = "unstable-split")]
/// Create a split `WebSocketRead`/`WebSocketWrite` pair from a stream that has already completed the WebSocket handshake.
pub fn after_handshake_split<R, W>(
read: R,
write: W,
role: Role,
) -> (WebSocketRead<R>, WebSocketWrite<W>)
where
R: AsyncRead + Unpin,
W: AsyncWrite + Unpin,
{
(
WebSocketRead {
stream: read,
read_half: ReadHalf::after_handshake(role),
},
WebSocketWrite {
stream: write,
write_half: WriteHalf::after_handshake(role),
},
)
}
#[cfg(feature = "unstable-split")]
impl<'f, S> WebSocketRead<S> {
/// Consumes the `WebSocketRead` and returns the underlying stream.
#[inline]
pub(crate) fn into_parts_internal(self) -> (S, ReadHalf) {
(self.stream, self.read_half)
}
pub fn set_writev_threshold(&mut self, threshold: usize) {
self.read_half.writev_threshold = threshold;
}
/// Sets whether to automatically close the connection when a close frame is received. When set to `false`, the application will have to manually send close frames.
///
/// Default: `true`
pub fn set_auto_close(&mut self, auto_close: bool) {
self.read_half.auto_close = auto_close;
}
/// Sets whether to automatically send a pong frame when a ping frame is received.
///
/// Default: `true`
pub fn set_auto_pong(&mut self, auto_pong: bool) {
self.read_half.auto_pong = auto_pong;
}
/// Sets the maximum message size in bytes. If a message is received that is larger than this, the connection will be closed.
///
/// Default: 64 MiB
pub fn set_max_message_size(&mut self, max_message_size: usize) {
self.read_half.max_message_size = max_message_size;
}
/// Sets whether to automatically apply the mask to the frame payload.
///
/// Default: `true`
pub fn set_auto_apply_mask(&mut self, auto_apply_mask: bool) {
self.read_half.auto_apply_mask = auto_apply_mask;
}
/// Reads a frame from the stream.
pub async fn read_frame<R, E>(
&mut self,
send_fn: &mut impl FnMut(Frame<'f>) -> R,
) -> Result<Frame, WebSocketError>
where
S: AsyncRead + Unpin,
E: Into<Box<dyn std::error::Error + Send + Sync + 'static>>,
R: Future<Output = Result<(), E>>,
{
loop {
let (res, obligated_send) =
self.read_half.read_frame_inner(&mut self.stream).await;
if let Some(frame) = obligated_send {
let res = send_fn(frame).await;
res.map_err(|e| WebSocketError::SendError(e.into()))?;
}
if let Some(frame) = res? {
break Ok(frame);
}
}
}
}
#[cfg(feature = "unstable-split")]
impl<'f, S> WebSocketWrite<S> {
/// Sets whether to use vectored writes. This option does not guarantee that vectored writes will be always used.
///
/// Default: `true`
pub fn set_writev(&mut self, vectored: bool) {
self.write_half.vectored = vectored;
}
pub fn set_writev_threshold(&mut self, threshold: usize) {
self.write_half.writev_threshold = threshold;
}
/// Sets whether to automatically apply the mask to the frame payload.
///
/// Default: `true`
pub fn set_auto_apply_mask(&mut self, auto_apply_mask: bool) {
self.write_half.auto_apply_mask = auto_apply_mask;
}
pub fn is_closed(&self) -> bool {
self.write_half.closed
}
pub async fn write_frame(
&mut self,
frame: Frame<'f>,
) -> Result<(), WebSocketError>
where
S: AsyncWrite + Unpin,
{
self.write_half.write_frame(&mut self.stream, frame).await
}
}
/// WebSocket protocol implementation over an async stream.
pub struct WebSocket<S> {
stream: S,
write_half: WriteHalf,
read_half: ReadHalf,
}
impl<'f, S> WebSocket<S> {
/// Creates a new `WebSocket` from a stream that has already completed the WebSocket handshake.
///
/// Use the `upgrade` feature to handle server upgrades and client handshakes.
///
/// # Example
///
/// ```
/// use tokio::net::TcpStream;
/// use fastwebsockets::{WebSocket, OpCode, Role};
/// use anyhow::Result;
///
/// async fn handle_client(
/// socket: TcpStream,
/// ) -> Result<()> {
/// let mut ws = WebSocket::after_handshake(socket, Role::Server);
/// // ...
/// Ok(())
/// }
/// ```
pub fn after_handshake(stream: S, role: Role) -> Self
where
S: AsyncRead + AsyncWrite + Unpin,
{
Self {
stream,
write_half: WriteHalf::after_handshake(role),
read_half: ReadHalf::after_handshake(role),
}
}
/// Split a [`WebSocket`] into a [`WebSocketRead`] and [`WebSocketWrite`] half. Note that the split version does not
/// handle fragmented packets and you may wish to create a [`FragmentCollectorRead`] over top of the read half that
/// is returned.
#[cfg(feature = "unstable-split")]
pub fn split<R, W>(
self,
split_fn: impl Fn(S) -> (R, W),
) -> (WebSocketRead<R>, WebSocketWrite<W>)
where
S: AsyncRead + AsyncWrite + Unpin,
R: AsyncRead + Unpin,
W: AsyncWrite + Unpin,
{
let (stream, read, write) = self.into_parts_internal();
let (r, w) = split_fn(stream);
(
WebSocketRead {
stream: r,
read_half: read,
},
WebSocketWrite {
stream: w,
write_half: write,
},
)
}
/// Consumes the `WebSocket` and returns the underlying stream.
#[inline]
pub fn into_inner(self) -> S {
// self.write_half.into_inner().stream
self.stream
}
/// Consumes the `WebSocket` and returns the underlying stream.
#[inline]
pub(crate) fn into_parts_internal(self) -> (S, ReadHalf, WriteHalf) {
(self.stream, self.read_half, self.write_half)
}
/// Sets whether to use vectored writes. This option does not guarantee that vectored writes will be always used.
///
/// Default: `true`
pub fn set_writev(&mut self, vectored: bool) {
self.write_half.vectored = vectored;
}
pub fn set_writev_threshold(&mut self, threshold: usize) {
self.read_half.writev_threshold = threshold;
self.write_half.writev_threshold = threshold;
}
/// Sets whether to automatically close the connection when a close frame is received. When set to `false`, the application will have to manually send close frames.
///
/// Default: `true`
pub fn set_auto_close(&mut self, auto_close: bool) {
self.read_half.auto_close = auto_close;
}
/// Sets whether to automatically send a pong frame when a ping frame is received.
///
/// Default: `true`
pub fn set_auto_pong(&mut self, auto_pong: bool) {
self.read_half.auto_pong = auto_pong;
}
/// Sets the maximum message size in bytes. If a message is received that is larger than this, the connection will be closed.
///
/// Default: 64 MiB
pub fn set_max_message_size(&mut self, max_message_size: usize) {
self.read_half.max_message_size = max_message_size;
}
/// Sets whether to automatically apply the mask to the frame payload.
///
/// Default: `true`
pub fn set_auto_apply_mask(&mut self, auto_apply_mask: bool) {
self.read_half.auto_apply_mask = auto_apply_mask;
self.write_half.auto_apply_mask = auto_apply_mask;
}
pub fn is_closed(&self) -> bool {
self.write_half.closed
}
/// Writes a frame to the stream.
///
/// # Example
///
/// ```
/// use fastwebsockets::{WebSocket, Frame, OpCode};
/// use tokio::net::TcpStream;
/// use anyhow::Result;
///
/// async fn send(
/// ws: &mut WebSocket<TcpStream>
/// ) -> Result<()> {
/// let mut frame = Frame::binary(vec![0x01, 0x02, 0x03].into());
/// ws.write_frame(frame).await?;
/// Ok(())
/// }
/// ```
pub async fn write_frame(
&mut self,
frame: Frame<'f>,
) -> Result<(), WebSocketError>
where
S: AsyncRead + AsyncWrite + Unpin,
{
self.write_half.write_frame(&mut self.stream, frame).await?;
Ok(())
}
/// Reads a frame from the stream.
///
/// This method will unmask the frame payload. For fragmented frames, use `FragmentCollector::read_frame`.
///
/// Text frames payload is guaranteed to be valid UTF-8.
///
/// # Example
///
/// ```
/// use fastwebsockets::{OpCode, WebSocket, Frame};
/// use tokio::net::TcpStream;
/// use anyhow::Result;
///
/// async fn echo(
/// ws: &mut WebSocket<TcpStream>
/// ) -> Result<()> {
/// let frame = ws.read_frame().await?;
/// match frame.opcode {
/// OpCode::Text | OpCode::Binary => {
/// ws.write_frame(frame).await?;
/// }
/// _ => {}
/// }
/// Ok(())
/// }
/// ```
pub async fn read_frame(&mut self) -> Result<Frame<'f>, WebSocketError>
where
S: AsyncRead + AsyncWrite + Unpin,
{
loop {
let (res, obligated_send) =
self.read_half.read_frame_inner(&mut self.stream).await;
let is_closed = self.write_half.closed;
if let Some(frame) = obligated_send {
if !is_closed {
self.write_half.write_frame(&mut self.stream, frame).await?;
}
}
if let Some(frame) = res? {
if is_closed && frame.opcode != OpCode::Close {
return Err(WebSocketError::ConnectionClosed);
}
break Ok(frame);
}
}
}
}
const MAX_HEADER_SIZE: usize = 14;
impl ReadHalf {
pub fn after_handshake(role: Role) -> Self {
let buffer = BytesMut::with_capacity(8192);
Self {
role,
auto_apply_mask: true,
auto_close: true,
auto_pong: true,
writev_threshold: 1024,
max_message_size: 64 << 20,
buffer,
}
}
/// Attempt to read a single frame from from the incoming stream, returning any send obligations if
/// `auto_close` or `auto_pong` are enabled. Callers to this function are obligated to send the
/// frame in the latter half of the tuple if one is specified, unless the write half of this socket
/// has been closed.
///
/// XXX: Do not expose this method to the public API.
pub(crate) async fn read_frame_inner<'f, S>(
&mut self,
stream: &mut S,
) -> (Result<Option<Frame<'f>>, WebSocketError>, Option<Frame<'f>>)
where
S: AsyncRead + Unpin,
{
let mut frame = match self.parse_frame_header(stream).await {
Ok(frame) => frame,
Err(e) => return (Err(e), None),
};
if self.role == Role::Server && self.auto_apply_mask {
frame.unmask()
};
match frame.opcode {
OpCode::Close if self.auto_close => {
match frame.payload.len() {
0 => {}
1 => return (Err(WebSocketError::InvalidCloseFrame), None),
_ => {
let code = close::CloseCode::from(u16::from_be_bytes(
frame.payload[0..2].try_into().unwrap(),
));
#[cfg(feature = "simd")]
if simdutf8::basic::from_utf8(&frame.payload[2..]).is_err() {
return (Err(WebSocketError::InvalidUTF8), None);
};
#[cfg(not(feature = "simd"))]
if std::str::from_utf8(&frame.payload[2..]).is_err() {
return (Err(WebSocketError::InvalidUTF8), None);
};
if !code.is_allowed() {
return (
Err(WebSocketError::InvalidCloseCode),
Some(Frame::close(1002, &frame.payload[2..])),
);
}
}
};
let obligated_send = Frame::close_raw(frame.payload.to_owned().into());
(Ok(Some(frame)), Some(obligated_send))
}
OpCode::Ping if self.auto_pong => {
(Ok(None), Some(Frame::pong(frame.payload)))
}
OpCode::Text => {
if frame.fin && !frame.is_utf8() {
(Err(WebSocketError::InvalidUTF8), None)
} else {
(Ok(Some(frame)), None)
}
}
_ => (Ok(Some(frame)), None),
}
}
async fn parse_frame_header<'a, S>(
&mut self,
stream: &mut S,
) -> Result<Frame<'a>, WebSocketError>
where
S: AsyncRead + Unpin,
{
macro_rules! eof {
($n:expr) => {{
if $n == 0 {
return Err(WebSocketError::UnexpectedEOF);
}
}};
}
// Read the first two bytes
while self.buffer.remaining() < 2 {
eof!(stream.read_buf(&mut self.buffer).await?);
}
let fin = self.buffer[0] & 0b10000000 != 0;
let rsv1 = self.buffer[0] & 0b01000000 != 0;
let rsv2 = self.buffer[0] & 0b00100000 != 0;
let rsv3 = self.buffer[0] & 0b00010000 != 0;
if rsv1 || rsv2 || rsv3 {
return Err(WebSocketError::ReservedBitsNotZero);
}
let opcode = frame::OpCode::try_from(self.buffer[0] & 0b00001111)?;
let masked = self.buffer[1] & 0b10000000 != 0;
let length_code = self.buffer[1] & 0x7F;
let extra = match length_code {
126 => 2,
127 => 8,
_ => 0,
};
self.buffer.advance(2);
while self.buffer.remaining() < extra + masked as usize * 4 {
eof!(stream.read_buf(&mut self.buffer).await?);
}
let payload_len: usize = match extra {
0 => usize::from(length_code),
2 => self.buffer.get_u16() as usize,
#[cfg(any(target_pointer_width = "64", target_pointer_width = "128"))]
8 => self.buffer.get_u64() as usize,
// On 32bit systems, usize is only 4bytes wide so we must check for usize overflowing
#[cfg(any(
target_pointer_width = "8",
target_pointer_width = "16",
target_pointer_width = "32"
))]
8 => match usize::try_from(self.buffer.get_u64()) {
Ok(length) => length,
Err(_) => return Err(WebSocketError::FrameTooLarge),
},
_ => unreachable!(),
};
let mask = if masked {
Some(self.buffer.get_u32().to_be_bytes())
} else {
None
};
if frame::is_control(opcode) && !fin {
return Err(WebSocketError::ControlFrameFragmented);
}
if opcode == OpCode::Ping && payload_len > 125 {
return Err(WebSocketError::PingFrameTooLarge);
}
if payload_len >= self.max_message_size {
return Err(WebSocketError::FrameTooLarge);
}
// Reserve a bit more to try to get next frame header and avoid a syscall to read it next time
self.buffer.reserve(payload_len + MAX_HEADER_SIZE);
while payload_len > self.buffer.remaining() {
eof!(stream.read_buf(&mut self.buffer).await?);
}
// if we read too much it will stay in the buffer, for the next call to this method
let payload = self.buffer.split_to(payload_len);
let frame = Frame::new(fin, opcode, mask, Payload::Bytes(payload));
Ok(frame)
}
}
impl WriteHalf {
pub fn after_handshake(role: Role) -> Self {
Self {
role,
closed: false,
auto_apply_mask: true,
vectored: true,
writev_threshold: 1024,
write_buffer: Vec::with_capacity(2),
}
}
/// Writes a frame to the provided stream.
pub async fn write_frame<'a, S>(
&'a mut self,
stream: &mut S,
mut frame: Frame<'a>,
) -> Result<(), WebSocketError>
where
S: AsyncWrite + Unpin,
{
if self.role == Role::Client && self.auto_apply_mask {
frame.mask();
}
if frame.opcode == OpCode::Close {
self.closed = true;
} else if self.closed {
return Err(WebSocketError::ConnectionClosed);
}
if self.vectored && frame.payload.len() > self.writev_threshold {
frame.writev(stream).await?;
} else {
let text = frame.write(&mut self.write_buffer);
stream.write_all(text).await?;
}
Ok(())
}
}
#[cfg(test)]
mod tests {
use super::*;
const _: () = {
const fn assert_unsync<S>() {
// Generic trait with a blanket impl over `()` for all types.
trait AmbiguousIfImpl<A> {
// Required for actually being able to reference the trait.
fn some_item() {}
}
impl<T: ?Sized> AmbiguousIfImpl<()> for T {}
// Used for the specialized impl when *all* traits in
// `$($t)+` are implemented.
#[allow(dead_code)]
struct Invalid;
impl<T: ?Sized + Sync> AmbiguousIfImpl<Invalid> for T {}
// If there is only one specialized trait impl, type inference with
// `_` can be resolved and this can compile. Fails to compile if
// `$x` implements `AmbiguousIfImpl<Invalid>`.
let _ = <S as AmbiguousIfImpl<_>>::some_item;
}
assert_unsync::<WebSocket<tokio::net::TcpStream>>();
};
}