tungstenite/protocol/mod.rs
1//! Generic WebSocket message stream.
2
3pub mod frame;
4
5mod message;
6
7pub use self::{frame::CloseFrame, message::Message};
8
9use self::{
10 frame::{
11 coding::{CloseCode, Control as OpCtl, Data as OpData, OpCode},
12 Frame, FrameCodec,
13 },
14 message::{IncompleteMessage, MessageType},
15};
16use crate::{
17 error::{CapacityError, Error, ProtocolError, Result},
18 protocol::frame::Utf8Bytes,
19};
20use log::*;
21use std::{
22 io::{self, Read, Write},
23 mem::replace,
24};
25
26/// Indicates a Client or Server role of the websocket
27#[derive(Debug, Clone, Copy, PartialEq, Eq)]
28pub enum Role {
29 /// This socket is a server
30 Server,
31 /// This socket is a client
32 Client,
33}
34
35/// The configuration for WebSocket connection.
36///
37/// # Example
38/// ```
39/// # use tungstenite::protocol::WebSocketConfig;;
40/// let conf = WebSocketConfig::default()
41/// .read_buffer_size(256 * 1024)
42/// .write_buffer_size(256 * 1024);
43/// ```
44#[derive(Debug, Clone, Copy)]
45#[non_exhaustive]
46pub struct WebSocketConfig {
47 /// Read buffer capacity. This buffer is eagerly allocated and used for receiving
48 /// messages.
49 ///
50 /// For high read load scenarios a larger buffer, e.g. 128 KiB, improves performance.
51 ///
52 /// For scenarios where you expect a lot of connections and don't need high read load
53 /// performance a smaller buffer, e.g. 4 KiB, would be appropriate to lower total
54 /// memory usage.
55 ///
56 /// The default value is 128 KiB.
57 pub read_buffer_size: usize,
58 /// The target minimum size of the write buffer to reach before writing the data
59 /// to the underlying stream.
60 /// The default value is 128 KiB.
61 ///
62 /// If set to `0` each message will be eagerly written to the underlying stream.
63 /// It is often more optimal to allow them to buffer a little, hence the default value.
64 ///
65 /// Note: [`flush`](WebSocket::flush) will always fully write the buffer regardless.
66 pub write_buffer_size: usize,
67 /// The max size of the write buffer in bytes. Setting this can provide backpressure
68 /// in the case the write buffer is filling up due to write errors.
69 /// The default value is unlimited.
70 ///
71 /// Note: The write buffer only builds up past [`write_buffer_size`](Self::write_buffer_size)
72 /// when writes to the underlying stream are failing. So the **write buffer can not
73 /// fill up if you are not observing write errors even if not flushing**.
74 ///
75 /// Note: Should always be at least [`write_buffer_size + 1 message`](Self::write_buffer_size)
76 /// and probably a little more depending on error handling strategy.
77 pub max_write_buffer_size: usize,
78 /// The maximum size of an incoming message. `None` means no size limit. The default value is 64 MiB
79 /// which should be reasonably big for all normal use-cases but small enough to prevent
80 /// memory eating by a malicious user.
81 pub max_message_size: Option<usize>,
82 /// The maximum size of a single incoming message frame. `None` means no size limit. The limit is for
83 /// frame payload NOT including the frame header. The default value is 16 MiB which should
84 /// be reasonably big for all normal use-cases but small enough to prevent memory eating
85 /// by a malicious user.
86 pub max_frame_size: Option<usize>,
87 /// When set to `true`, the server will accept and handle unmasked frames
88 /// from the client. According to the RFC 6455, the server must close the
89 /// connection to the client in such cases, however it seems like there are
90 /// some popular libraries that are sending unmasked frames, ignoring the RFC.
91 /// By default this option is set to `false`, i.e. according to RFC 6455.
92 pub accept_unmasked_frames: bool,
93}
94
95impl Default for WebSocketConfig {
96 fn default() -> Self {
97 Self {
98 read_buffer_size: 128 * 1024,
99 write_buffer_size: 128 * 1024,
100 max_write_buffer_size: usize::MAX,
101 max_message_size: Some(64 << 20),
102 max_frame_size: Some(16 << 20),
103 accept_unmasked_frames: false,
104 }
105 }
106}
107
108impl WebSocketConfig {
109 /// Set [`Self::read_buffer_size`].
110 pub fn read_buffer_size(mut self, read_buffer_size: usize) -> Self {
111 self.read_buffer_size = read_buffer_size;
112 self
113 }
114
115 /// Set [`Self::write_buffer_size`].
116 pub fn write_buffer_size(mut self, write_buffer_size: usize) -> Self {
117 self.write_buffer_size = write_buffer_size;
118 self
119 }
120
121 /// Set [`Self::max_write_buffer_size`].
122 pub fn max_write_buffer_size(mut self, max_write_buffer_size: usize) -> Self {
123 self.max_write_buffer_size = max_write_buffer_size;
124 self
125 }
126
127 /// Set [`Self::max_message_size`].
128 pub fn max_message_size(mut self, max_message_size: Option<usize>) -> Self {
129 self.max_message_size = max_message_size;
130 self
131 }
132
133 /// Set [`Self::max_frame_size`].
134 pub fn max_frame_size(mut self, max_frame_size: Option<usize>) -> Self {
135 self.max_frame_size = max_frame_size;
136 self
137 }
138
139 /// Set [`Self::accept_unmasked_frames`].
140 pub fn accept_unmasked_frames(mut self, accept_unmasked_frames: bool) -> Self {
141 self.accept_unmasked_frames = accept_unmasked_frames;
142 self
143 }
144
145 /// Panic if values are invalid.
146 pub(crate) fn assert_valid(&self) {
147 assert!(
148 self.max_write_buffer_size > self.write_buffer_size,
149 "WebSocketConfig::max_write_buffer_size must be greater than write_buffer_size, \
150 see WebSocketConfig docs`"
151 );
152 }
153}
154
155/// WebSocket input-output stream.
156///
157/// This is THE structure you want to create to be able to speak the WebSocket protocol.
158/// It may be created by calling `connect`, `accept` or `client` functions.
159///
160/// Use [`WebSocket::read`], [`WebSocket::send`] to received and send messages.
161#[derive(Debug)]
162pub struct WebSocket<Stream> {
163 /// The underlying socket.
164 socket: Stream,
165 /// The context for managing a WebSocket.
166 context: WebSocketContext,
167}
168
169impl<Stream> WebSocket<Stream> {
170 /// Convert a raw socket into a WebSocket without performing a handshake.
171 ///
172 /// Call this function if you're using Tungstenite as a part of a web framework
173 /// or together with an existing one. If you need an initial handshake, use
174 /// `connect()` or `accept()` functions of the crate to construct a websocket.
175 ///
176 /// # Panics
177 /// Panics if config is invalid e.g. `max_write_buffer_size <= write_buffer_size`.
178 pub fn from_raw_socket(stream: Stream, role: Role, config: Option<WebSocketConfig>) -> Self {
179 WebSocket { socket: stream, context: WebSocketContext::new(role, config) }
180 }
181
182 /// Convert a raw socket into a WebSocket without performing a handshake.
183 ///
184 /// Call this function if you're using Tungstenite as a part of a web framework
185 /// or together with an existing one. If you need an initial handshake, use
186 /// `connect()` or `accept()` functions of the crate to construct a websocket.
187 ///
188 /// # Panics
189 /// Panics if config is invalid e.g. `max_write_buffer_size <= write_buffer_size`.
190 pub fn from_partially_read(
191 stream: Stream,
192 part: Vec<u8>,
193 role: Role,
194 config: Option<WebSocketConfig>,
195 ) -> Self {
196 WebSocket {
197 socket: stream,
198 context: WebSocketContext::from_partially_read(part, role, config),
199 }
200 }
201
202 /// Consumes the `WebSocket` and returns the underlying stream.
203 pub fn into_inner(self) -> Stream {
204 self.socket
205 }
206
207 /// Returns a shared reference to the inner stream.
208 pub fn get_ref(&self) -> &Stream {
209 &self.socket
210 }
211 /// Returns a mutable reference to the inner stream.
212 pub fn get_mut(&mut self) -> &mut Stream {
213 &mut self.socket
214 }
215
216 /// Change the configuration.
217 ///
218 /// # Panics
219 /// Panics if config is invalid e.g. `max_write_buffer_size <= write_buffer_size`.
220 pub fn set_config(&mut self, set_func: impl FnOnce(&mut WebSocketConfig)) {
221 self.context.set_config(set_func);
222 }
223
224 /// Read the configuration.
225 pub fn get_config(&self) -> &WebSocketConfig {
226 self.context.get_config()
227 }
228
229 /// Check if it is possible to read messages.
230 ///
231 /// Reading is impossible after receiving `Message::Close`. It is still possible after
232 /// sending close frame since the peer still may send some data before confirming close.
233 pub fn can_read(&self) -> bool {
234 self.context.can_read()
235 }
236
237 /// Check if it is possible to write messages.
238 ///
239 /// Writing gets impossible immediately after sending or receiving `Message::Close`.
240 pub fn can_write(&self) -> bool {
241 self.context.can_write()
242 }
243}
244
245impl<Stream: Read + Write> WebSocket<Stream> {
246 /// Read a message from stream, if possible.
247 ///
248 /// This will also queue responses to ping and close messages. These responses
249 /// will be written and flushed on the next call to [`read`](Self::read),
250 /// [`write`](Self::write) or [`flush`](Self::flush).
251 ///
252 /// # Closing the connection
253 /// When the remote endpoint decides to close the connection this will return
254 /// the close message with an optional close frame.
255 ///
256 /// You should continue calling [`read`](Self::read), [`write`](Self::write) or
257 /// [`flush`](Self::flush) to drive the reply to the close frame until [`Error::ConnectionClosed`]
258 /// is returned. Once that happens it is safe to drop the underlying connection.
259 pub fn read(&mut self) -> Result<Message> {
260 self.context.read(&mut self.socket)
261 }
262
263 /// Writes and immediately flushes a message.
264 /// Equivalent to calling [`write`](Self::write) then [`flush`](Self::flush).
265 pub fn send(&mut self, message: Message) -> Result<()> {
266 self.write(message)?;
267 self.flush()
268 }
269
270 /// Write a message to the provided stream, if possible.
271 ///
272 /// A subsequent call should be made to [`flush`](Self::flush) to flush writes.
273 ///
274 /// In the event of stream write failure the message frame will be stored
275 /// in the write buffer and will try again on the next call to [`write`](Self::write)
276 /// or [`flush`](Self::flush).
277 ///
278 /// If the write buffer would exceed the configured [`WebSocketConfig::max_write_buffer_size`]
279 /// [`Err(WriteBufferFull(msg_frame))`](Error::WriteBufferFull) is returned.
280 ///
281 /// This call will generally not flush. However, if there are queued automatic messages
282 /// they will be written and eagerly flushed.
283 ///
284 /// For example, upon receiving ping messages tungstenite queues pong replies automatically.
285 /// The next call to [`read`](Self::read), [`write`](Self::write) or [`flush`](Self::flush)
286 /// will write & flush the pong reply. This means you should not respond to ping frames manually.
287 ///
288 /// You can however send pong frames manually in order to indicate a unidirectional heartbeat
289 /// as described in [RFC 6455](https://tools.ietf.org/html/rfc6455#section-5.5.3). Note that
290 /// if [`read`](Self::read) returns a ping, you should [`flush`](Self::flush) before passing
291 /// a custom pong to [`write`](Self::write), otherwise the automatic queued response to the
292 /// ping will not be sent as it will be replaced by your custom pong message.
293 ///
294 /// # Errors
295 /// - If the WebSocket's write buffer is full, [`Error::WriteBufferFull`] will be returned
296 /// along with the equivalent passed message frame.
297 /// - If the connection is closed and should be dropped, this will return [`Error::ConnectionClosed`].
298 /// - If you try again after [`Error::ConnectionClosed`] was returned either from here or from
299 /// [`read`](Self::read), [`Error::AlreadyClosed`] will be returned. This indicates a program
300 /// error on your part.
301 /// - [`Error::Io`] is returned if the underlying connection returns an error
302 /// (consider these fatal except for WouldBlock).
303 /// - [`Error::Capacity`] if your message size is bigger than the configured max message size.
304 pub fn write(&mut self, message: Message) -> Result<()> {
305 self.context.write(&mut self.socket, message)
306 }
307
308 /// Flush writes.
309 ///
310 /// Ensures all messages previously passed to [`write`](Self::write) and automatic
311 /// queued pong responses are written & flushed into the underlying stream.
312 pub fn flush(&mut self) -> Result<()> {
313 self.context.flush(&mut self.socket)
314 }
315
316 /// Close the connection.
317 ///
318 /// This function guarantees that the close frame will be queued.
319 /// There is no need to call it again. Calling this function is
320 /// the same as calling `write(Message::Close(..))`.
321 ///
322 /// After queuing the close frame you should continue calling [`read`](Self::read) or
323 /// [`flush`](Self::flush) to drive the close handshake to completion.
324 ///
325 /// The websocket RFC defines that the underlying connection should be closed
326 /// by the server. Tungstenite takes care of this asymmetry for you.
327 ///
328 /// When the close handshake is finished (we have both sent and received
329 /// a close message), [`read`](Self::read) or [`flush`](Self::flush) will return
330 /// [Error::ConnectionClosed] if this endpoint is the server.
331 ///
332 /// If this endpoint is a client, [Error::ConnectionClosed] will only be
333 /// returned after the server has closed the underlying connection.
334 ///
335 /// It is thus safe to drop the underlying connection as soon as [Error::ConnectionClosed]
336 /// is returned from [`read`](Self::read) or [`flush`](Self::flush).
337 pub fn close(&mut self, code: Option<CloseFrame>) -> Result<()> {
338 self.context.close(&mut self.socket, code)
339 }
340
341 /// Old name for [`read`](Self::read).
342 #[deprecated(note = "Use `read`")]
343 pub fn read_message(&mut self) -> Result<Message> {
344 self.read()
345 }
346
347 /// Old name for [`send`](Self::send).
348 #[deprecated(note = "Use `send`")]
349 pub fn write_message(&mut self, message: Message) -> Result<()> {
350 self.send(message)
351 }
352
353 /// Old name for [`flush`](Self::flush).
354 #[deprecated(note = "Use `flush`")]
355 pub fn write_pending(&mut self) -> Result<()> {
356 self.flush()
357 }
358}
359
360/// A context for managing WebSocket stream.
361#[derive(Debug)]
362pub struct WebSocketContext {
363 /// Server or client?
364 role: Role,
365 /// encoder/decoder of frame.
366 frame: FrameCodec,
367 /// The state of processing, either "active" or "closing".
368 state: WebSocketState,
369 /// Receive: an incomplete message being processed.
370 incomplete: Option<IncompleteMessage>,
371 /// Send in addition to regular messages E.g. "pong" or "close".
372 additional_send: Option<Frame>,
373 /// True indicates there is an additional message (like a pong)
374 /// that failed to flush previously and we should try again.
375 unflushed_additional: bool,
376 /// The configuration for the websocket session.
377 config: WebSocketConfig,
378}
379
380impl WebSocketContext {
381 /// Create a WebSocket context that manages a post-handshake stream.
382 ///
383 /// # Panics
384 /// Panics if config is invalid e.g. `max_write_buffer_size <= write_buffer_size`.
385 pub fn new(role: Role, config: Option<WebSocketConfig>) -> Self {
386 let conf = config.unwrap_or_default();
387 Self::_new(role, FrameCodec::new(conf.read_buffer_size), conf)
388 }
389
390 /// Create a WebSocket context that manages an post-handshake stream.
391 ///
392 /// # Panics
393 /// Panics if config is invalid e.g. `max_write_buffer_size <= write_buffer_size`.
394 pub fn from_partially_read(part: Vec<u8>, role: Role, config: Option<WebSocketConfig>) -> Self {
395 let conf = config.unwrap_or_default();
396 Self::_new(role, FrameCodec::from_partially_read(part, conf.read_buffer_size), conf)
397 }
398
399 fn _new(role: Role, mut frame: FrameCodec, config: WebSocketConfig) -> Self {
400 config.assert_valid();
401 frame.set_max_out_buffer_len(config.max_write_buffer_size);
402 frame.set_out_buffer_write_len(config.write_buffer_size);
403 Self {
404 role,
405 frame,
406 state: WebSocketState::Active,
407 incomplete: None,
408 additional_send: None,
409 unflushed_additional: false,
410 config,
411 }
412 }
413
414 /// Change the configuration.
415 ///
416 /// # Panics
417 /// Panics if config is invalid e.g. `max_write_buffer_size <= write_buffer_size`.
418 pub fn set_config(&mut self, set_func: impl FnOnce(&mut WebSocketConfig)) {
419 set_func(&mut self.config);
420 self.config.assert_valid();
421 self.frame.set_max_out_buffer_len(self.config.max_write_buffer_size);
422 self.frame.set_out_buffer_write_len(self.config.write_buffer_size);
423 }
424
425 /// Read the configuration.
426 pub fn get_config(&self) -> &WebSocketConfig {
427 &self.config
428 }
429
430 /// Check if it is possible to read messages.
431 ///
432 /// Reading is impossible after receiving `Message::Close`. It is still possible after
433 /// sending close frame since the peer still may send some data before confirming close.
434 pub fn can_read(&self) -> bool {
435 self.state.can_read()
436 }
437
438 /// Check if it is possible to write messages.
439 ///
440 /// Writing gets impossible immediately after sending or receiving `Message::Close`.
441 pub fn can_write(&self) -> bool {
442 self.state.is_active()
443 }
444
445 /// Read a message from the provided stream, if possible.
446 ///
447 /// This function sends pong and close responses automatically.
448 /// However, it never blocks on write.
449 pub fn read<Stream>(&mut self, stream: &mut Stream) -> Result<Message>
450 where
451 Stream: Read + Write,
452 {
453 // Do not read from already closed connections.
454 self.state.check_not_terminated()?;
455
456 loop {
457 if self.additional_send.is_some() || self.unflushed_additional {
458 // Since we may get ping or close, we need to reply to the messages even during read.
459 match self.flush(stream) {
460 Ok(_) => {}
461 Err(Error::Io(err)) if err.kind() == io::ErrorKind::WouldBlock => {
462 // If blocked continue reading, but try again later
463 self.unflushed_additional = true;
464 }
465 Err(err) => return Err(err),
466 }
467 } else if self.role == Role::Server && !self.state.can_read() {
468 self.state = WebSocketState::Terminated;
469 return Err(Error::ConnectionClosed);
470 }
471
472 // If we get here, either write blocks or we have nothing to write.
473 // Thus if read blocks, just let it return WouldBlock.
474 if let Some(message) = self.read_message_frame(stream)? {
475 trace!("Received message {message}");
476 return Ok(message);
477 }
478 }
479 }
480
481 /// Write a message to the provided stream.
482 ///
483 /// A subsequent call should be made to [`flush`](Self::flush) to flush writes.
484 ///
485 /// In the event of stream write failure the message frame will be stored
486 /// in the write buffer and will try again on the next call to [`write`](Self::write)
487 /// or [`flush`](Self::flush).
488 ///
489 /// If the write buffer would exceed the configured [`WebSocketConfig::max_write_buffer_size`]
490 /// [`Err(WriteBufferFull(msg_frame))`](Error::WriteBufferFull) is returned.
491 pub fn write<Stream>(&mut self, stream: &mut Stream, message: Message) -> Result<()>
492 where
493 Stream: Read + Write,
494 {
495 // When terminated, return AlreadyClosed.
496 self.state.check_not_terminated()?;
497
498 // Do not write after sending a close frame.
499 if !self.state.is_active() {
500 return Err(Error::Protocol(ProtocolError::SendAfterClosing));
501 }
502
503 let frame = match message {
504 Message::Text(data) => Frame::message(data, OpCode::Data(OpData::Text), true),
505 Message::Binary(data) => Frame::message(data, OpCode::Data(OpData::Binary), true),
506 Message::Ping(data) => Frame::ping(data),
507 Message::Pong(data) => {
508 self.set_additional(Frame::pong(data));
509 // Note: user pongs can be user flushed so no need to flush here
510 return self._write(stream, None).map(|_| ());
511 }
512 Message::Close(code) => return self.close(stream, code),
513 Message::Frame(f) => f,
514 };
515
516 let should_flush = self._write(stream, Some(frame))?;
517 if should_flush {
518 self.flush(stream)?;
519 }
520 Ok(())
521 }
522
523 /// Flush writes.
524 ///
525 /// Ensures all messages previously passed to [`write`](Self::write) and automatically
526 /// queued pong responses are written & flushed into the `stream`.
527 #[inline]
528 pub fn flush<Stream>(&mut self, stream: &mut Stream) -> Result<()>
529 where
530 Stream: Read + Write,
531 {
532 self._write(stream, None)?;
533 self.frame.write_out_buffer(stream)?;
534 stream.flush()?;
535 self.unflushed_additional = false;
536 Ok(())
537 }
538
539 /// Writes any data in the out_buffer, `additional_send` and given `data`.
540 ///
541 /// Does **not** flush.
542 ///
543 /// Returns true if the write contents indicate we should flush immediately.
544 fn _write<Stream>(&mut self, stream: &mut Stream, data: Option<Frame>) -> Result<bool>
545 where
546 Stream: Read + Write,
547 {
548 if let Some(data) = data {
549 self.buffer_frame(stream, data)?;
550 }
551
552 // Upon receipt of a Ping frame, an endpoint MUST send a Pong frame in
553 // response, unless it already received a Close frame. It SHOULD
554 // respond with Pong frame as soon as is practical. (RFC 6455)
555 let should_flush = if let Some(msg) = self.additional_send.take() {
556 trace!("Sending pong/close");
557 match self.buffer_frame(stream, msg) {
558 Err(Error::WriteBufferFull(msg)) => {
559 // if an system message would exceed the buffer put it back in
560 // `additional_send` for retry. Otherwise returning this error
561 // may not make sense to the user, e.g. calling `flush`.
562 if let Message::Frame(msg) = *msg {
563 self.set_additional(msg);
564 false
565 } else {
566 unreachable!()
567 }
568 }
569 Err(err) => return Err(err),
570 Ok(_) => true,
571 }
572 } else {
573 self.unflushed_additional
574 };
575
576 // If we're closing and there is nothing to send anymore, we should close the connection.
577 if self.role == Role::Server && !self.state.can_read() {
578 // The underlying TCP connection, in most normal cases, SHOULD be closed
579 // first by the server, so that it holds the TIME_WAIT state and not the
580 // client (as this would prevent it from re-opening the connection for 2
581 // maximum segment lifetimes (2MSL), while there is no corresponding
582 // server impact as a TIME_WAIT connection is immediately reopened upon
583 // a new SYN with a higher seq number). (RFC 6455)
584 self.frame.write_out_buffer(stream)?;
585 self.state = WebSocketState::Terminated;
586 Err(Error::ConnectionClosed)
587 } else {
588 Ok(should_flush)
589 }
590 }
591
592 /// Close the connection.
593 ///
594 /// This function guarantees that the close frame will be queued.
595 /// There is no need to call it again. Calling this function is
596 /// the same as calling `send(Message::Close(..))`.
597 pub fn close<Stream>(&mut self, stream: &mut Stream, code: Option<CloseFrame>) -> Result<()>
598 where
599 Stream: Read + Write,
600 {
601 if let WebSocketState::Active = self.state {
602 self.state = WebSocketState::ClosedByUs;
603 let frame = Frame::close(code);
604 self._write(stream, Some(frame))?;
605 }
606 self.flush(stream)
607 }
608
609 /// Try to decode one message frame. May return None.
610 fn read_message_frame(&mut self, stream: &mut impl Read) -> Result<Option<Message>> {
611 let frame = match self
612 .frame
613 .read_frame(
614 stream,
615 self.config.max_frame_size,
616 matches!(self.role, Role::Server),
617 self.config.accept_unmasked_frames,
618 )
619 .check_connection_reset(self.state)?
620 {
621 None => {
622 // Connection closed by peer
623 return match replace(&mut self.state, WebSocketState::Terminated) {
624 WebSocketState::ClosedByPeer | WebSocketState::CloseAcknowledged => {
625 Err(Error::ConnectionClosed)
626 }
627 _ => Err(Error::Protocol(ProtocolError::ResetWithoutClosingHandshake)),
628 };
629 }
630 Some(frame) => frame,
631 };
632
633 if !self.state.can_read() {
634 return Err(Error::Protocol(ProtocolError::ReceivedAfterClosing));
635 }
636 // MUST be 0 unless an extension is negotiated that defines meanings
637 // for non-zero values. If a nonzero value is received and none of
638 // the negotiated extensions defines the meaning of such a nonzero
639 // value, the receiving endpoint MUST _Fail the WebSocket
640 // Connection_.
641 {
642 let hdr = frame.header();
643 if hdr.rsv1 || hdr.rsv2 || hdr.rsv3 {
644 return Err(Error::Protocol(ProtocolError::NonZeroReservedBits));
645 }
646 }
647
648 if self.role == Role::Client && frame.is_masked() {
649 // A client MUST close a connection if it detects a masked frame. (RFC 6455)
650 return Err(Error::Protocol(ProtocolError::MaskedFrameFromServer));
651 }
652
653 match frame.header().opcode {
654 OpCode::Control(ctl) => {
655 match ctl {
656 // All control frames MUST have a payload length of 125 bytes or less
657 // and MUST NOT be fragmented. (RFC 6455)
658 _ if !frame.header().is_final => {
659 Err(Error::Protocol(ProtocolError::FragmentedControlFrame))
660 }
661 _ if frame.payload().len() > 125 => {
662 Err(Error::Protocol(ProtocolError::ControlFrameTooBig))
663 }
664 OpCtl::Close => Ok(self.do_close(frame.into_close()?).map(Message::Close)),
665 OpCtl::Reserved(i) => {
666 Err(Error::Protocol(ProtocolError::UnknownControlFrameType(i)))
667 }
668 OpCtl::Ping => {
669 let data = frame.into_payload();
670 // No ping processing after we sent a close frame.
671 if self.state.is_active() {
672 self.set_additional(Frame::pong(data.clone()));
673 }
674 Ok(Some(Message::Ping(data)))
675 }
676 OpCtl::Pong => Ok(Some(Message::Pong(frame.into_payload()))),
677 }
678 }
679
680 OpCode::Data(data) => {
681 let fin = frame.header().is_final;
682
683 let payload = match (data, self.incomplete.as_mut()) {
684 (OpData::Continue, None) => Err(ProtocolError::UnexpectedContinueFrame),
685 (OpData::Continue, Some(incomplete)) => {
686 incomplete.extend(frame.into_payload(), self.config.max_message_size)?;
687 Ok(None)
688 }
689 (_, Some(_)) => Err(ProtocolError::ExpectedFragment(data)),
690 (OpData::Text, _) => Ok(Some((frame.into_payload(), MessageType::Text))),
691 (OpData::Binary, _) => Ok(Some((frame.into_payload(), MessageType::Binary))),
692 (OpData::Reserved(i), _) => Err(ProtocolError::UnknownDataFrameType(i)),
693 }?;
694
695 match (payload, fin) {
696 (None, true) => Ok(Some(self.incomplete.take().unwrap().complete()?)),
697 (None, false) => Ok(None),
698 (Some((payload, t)), true) => {
699 check_max_size(payload.len(), self.config.max_message_size)?;
700 match t {
701 MessageType::Text => Ok(Some(Message::Text(payload.try_into()?))),
702 MessageType::Binary => Ok(Some(Message::Binary(payload))),
703 }
704 }
705 (Some((payload, t)), false) => {
706 let mut incomplete = IncompleteMessage::new(t);
707 incomplete.extend(payload, self.config.max_message_size)?;
708 self.incomplete = Some(incomplete);
709 Ok(None)
710 }
711 }
712 }
713 } // match opcode
714 }
715
716 /// Received a close frame. Tells if we need to return a close frame to the user.
717 #[allow(clippy::option_option)]
718 fn do_close(&mut self, close: Option<CloseFrame>) -> Option<Option<CloseFrame>> {
719 debug!("Received close frame: {close:?}");
720 match self.state {
721 WebSocketState::Active => {
722 self.state = WebSocketState::ClosedByPeer;
723
724 let close = close.map(|frame| {
725 if !frame.code.is_allowed() {
726 CloseFrame {
727 code: CloseCode::Protocol,
728 reason: Utf8Bytes::from_static("Protocol violation"),
729 }
730 } else {
731 frame
732 }
733 });
734
735 let reply = Frame::close(close.clone());
736 debug!("Replying to close with {reply:?}");
737 self.set_additional(reply);
738
739 Some(close)
740 }
741 WebSocketState::ClosedByPeer | WebSocketState::CloseAcknowledged => {
742 // It is already closed, just ignore.
743 None
744 }
745 WebSocketState::ClosedByUs => {
746 // We received a reply.
747 self.state = WebSocketState::CloseAcknowledged;
748 Some(close)
749 }
750 WebSocketState::Terminated => unreachable!(),
751 }
752 }
753
754 /// Write a single frame into the write-buffer.
755 fn buffer_frame<Stream>(&mut self, stream: &mut Stream, mut frame: Frame) -> Result<()>
756 where
757 Stream: Read + Write,
758 {
759 match self.role {
760 Role::Server => {}
761 Role::Client => {
762 // 5. If the data is being sent by the client, the frame(s) MUST be
763 // masked as defined in Section 5.3. (RFC 6455)
764 frame.set_random_mask();
765 }
766 }
767
768 trace!("Sending frame: {frame:?}");
769 self.frame.buffer_frame(stream, frame).check_connection_reset(self.state)
770 }
771
772 /// Replace `additional_send` if it is currently a `Pong` message.
773 fn set_additional(&mut self, add: Frame) {
774 let empty_or_pong = self
775 .additional_send
776 .as_ref()
777 .map_or(true, |f| f.header().opcode == OpCode::Control(OpCtl::Pong));
778 if empty_or_pong {
779 self.additional_send.replace(add);
780 }
781 }
782}
783
784fn check_max_size(size: usize, max_size: Option<usize>) -> crate::Result<()> {
785 if let Some(max_size) = max_size {
786 if size > max_size {
787 return Err(Error::Capacity(CapacityError::MessageTooLong { size, max_size }));
788 }
789 }
790 Ok(())
791}
792
793/// The current connection state.
794#[derive(Debug, PartialEq, Eq, Clone, Copy)]
795enum WebSocketState {
796 /// The connection is active.
797 Active,
798 /// We initiated a close handshake.
799 ClosedByUs,
800 /// The peer initiated a close handshake.
801 ClosedByPeer,
802 /// The peer replied to our close handshake.
803 CloseAcknowledged,
804 /// The connection does not exist anymore.
805 Terminated,
806}
807
808impl WebSocketState {
809 /// Tell if we're allowed to process normal messages.
810 fn is_active(self) -> bool {
811 matches!(self, WebSocketState::Active)
812 }
813
814 /// Tell if we should process incoming data. Note that if we send a close frame
815 /// but the remote hasn't confirmed, they might have sent data before they receive our
816 /// close frame, so we should still pass those to client code, hence ClosedByUs is valid.
817 fn can_read(self) -> bool {
818 matches!(self, WebSocketState::Active | WebSocketState::ClosedByUs)
819 }
820
821 /// Check if the state is active, return error if not.
822 fn check_not_terminated(self) -> Result<()> {
823 match self {
824 WebSocketState::Terminated => Err(Error::AlreadyClosed),
825 _ => Ok(()),
826 }
827 }
828}
829
830/// Translate "Connection reset by peer" into `ConnectionClosed` if appropriate.
831trait CheckConnectionReset {
832 fn check_connection_reset(self, state: WebSocketState) -> Self;
833}
834
835impl<T> CheckConnectionReset for Result<T> {
836 fn check_connection_reset(self, state: WebSocketState) -> Self {
837 match self {
838 Err(Error::Io(io_error)) => Err({
839 if !state.can_read() && io_error.kind() == io::ErrorKind::ConnectionReset {
840 Error::ConnectionClosed
841 } else {
842 Error::Io(io_error)
843 }
844 }),
845 x => x,
846 }
847 }
848}
849
850#[cfg(test)]
851mod tests {
852 use super::{Message, Role, WebSocket, WebSocketConfig};
853 use crate::error::{CapacityError, Error};
854
855 use std::{io, io::Cursor};
856
857 struct WriteMoc<Stream>(Stream);
858
859 impl<Stream> io::Write for WriteMoc<Stream> {
860 fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
861 Ok(buf.len())
862 }
863 fn flush(&mut self) -> io::Result<()> {
864 Ok(())
865 }
866 }
867
868 impl<Stream: io::Read> io::Read for WriteMoc<Stream> {
869 fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
870 self.0.read(buf)
871 }
872 }
873
874 #[test]
875 fn receive_messages() {
876 let incoming = Cursor::new(vec![
877 0x89, 0x02, 0x01, 0x02, 0x8a, 0x01, 0x03, 0x01, 0x07, 0x48, 0x65, 0x6c, 0x6c, 0x6f,
878 0x2c, 0x20, 0x80, 0x06, 0x57, 0x6f, 0x72, 0x6c, 0x64, 0x21, 0x82, 0x03, 0x01, 0x02,
879 0x03,
880 ]);
881 let mut socket = WebSocket::from_raw_socket(WriteMoc(incoming), Role::Client, None);
882 assert_eq!(socket.read().unwrap(), Message::Ping(vec![1, 2].into()));
883 assert_eq!(socket.read().unwrap(), Message::Pong(vec![3].into()));
884 assert_eq!(socket.read().unwrap(), Message::Text("Hello, World!".into()));
885 assert_eq!(socket.read().unwrap(), Message::Binary(vec![0x01, 0x02, 0x03].into()));
886 }
887
888 #[test]
889 fn size_limiting_text_fragmented() {
890 let incoming = Cursor::new(vec![
891 0x01, 0x07, 0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x2c, 0x20, 0x80, 0x06, 0x57, 0x6f, 0x72,
892 0x6c, 0x64, 0x21,
893 ]);
894 let limit = WebSocketConfig { max_message_size: Some(10), ..WebSocketConfig::default() };
895 let mut socket = WebSocket::from_raw_socket(WriteMoc(incoming), Role::Client, Some(limit));
896
897 assert!(matches!(
898 socket.read(),
899 Err(Error::Capacity(CapacityError::MessageTooLong { size: 13, max_size: 10 }))
900 ));
901 }
902
903 #[test]
904 fn size_limiting_binary() {
905 let incoming = Cursor::new(vec![0x82, 0x03, 0x01, 0x02, 0x03]);
906 let limit = WebSocketConfig { max_message_size: Some(2), ..WebSocketConfig::default() };
907 let mut socket = WebSocket::from_raw_socket(WriteMoc(incoming), Role::Client, Some(limit));
908
909 assert!(matches!(
910 socket.read(),
911 Err(Error::Capacity(CapacityError::MessageTooLong { size: 3, max_size: 2 }))
912 ));
913 }
914}