tungstenite/handshake/
client.rs

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1//! Client handshake machine.
2
3use std::{
4    io::{Read, Write},
5    marker::PhantomData,
6};
7
8use http::{
9    header::HeaderName, HeaderMap, Request as HttpRequest, Response as HttpResponse, StatusCode,
10};
11use httparse::Status;
12use log::*;
13
14use super::{
15    derive_accept_key,
16    headers::{FromHttparse, MAX_HEADERS},
17    machine::{HandshakeMachine, StageResult, TryParse},
18    HandshakeRole, MidHandshake, ProcessingResult,
19};
20use crate::{
21    error::{Error, ProtocolError, Result, SubProtocolError, UrlError},
22    protocol::{Role, WebSocket, WebSocketConfig},
23};
24
25/// Client request type.
26pub type Request = HttpRequest<()>;
27
28/// Client response type.
29pub type Response = HttpResponse<Option<Vec<u8>>>;
30
31/// Client handshake role.
32#[derive(Debug)]
33pub struct ClientHandshake<S> {
34    verify_data: VerifyData,
35    config: Option<WebSocketConfig>,
36    _marker: PhantomData<S>,
37}
38
39impl<S: Read + Write> ClientHandshake<S> {
40    /// Initiate a client handshake.
41    pub fn start(
42        stream: S,
43        request: Request,
44        config: Option<WebSocketConfig>,
45    ) -> Result<MidHandshake<Self>> {
46        if request.method() != http::Method::GET {
47            return Err(Error::Protocol(ProtocolError::WrongHttpMethod));
48        }
49
50        if request.version() < http::Version::HTTP_11 {
51            return Err(Error::Protocol(ProtocolError::WrongHttpVersion));
52        }
53
54        // Check the URI scheme: only ws or wss are supported
55        let _ = crate::client::uri_mode(request.uri())?;
56
57        let subprotocols = extract_subprotocols_from_request(&request)?;
58
59        // Convert and verify the `http::Request` and turn it into the request as per RFC.
60        // Also extract the key from it (it must be present in a correct request).
61        let (request, key) = generate_request(request)?;
62
63        let machine = HandshakeMachine::start_write(stream, request);
64
65        let client = {
66            let accept_key = derive_accept_key(key.as_ref());
67            ClientHandshake {
68                verify_data: VerifyData { accept_key, subprotocols },
69                config,
70                _marker: PhantomData,
71            }
72        };
73
74        trace!("Client handshake initiated.");
75        Ok(MidHandshake { role: client, machine })
76    }
77}
78
79impl<S: Read + Write> HandshakeRole for ClientHandshake<S> {
80    type IncomingData = Response;
81    type InternalStream = S;
82    type FinalResult = (WebSocket<S>, Response);
83    fn stage_finished(
84        &mut self,
85        finish: StageResult<Self::IncomingData, Self::InternalStream>,
86    ) -> Result<ProcessingResult<Self::InternalStream, Self::FinalResult>> {
87        Ok(match finish {
88            StageResult::DoneWriting(stream) => {
89                ProcessingResult::Continue(HandshakeMachine::start_read(stream))
90            }
91            StageResult::DoneReading { stream, result, tail } => {
92                let result = match self.verify_data.verify_response(result) {
93                    Ok(r) => r,
94                    Err(Error::Http(mut e)) => {
95                        *e.body_mut() = Some(tail);
96                        return Err(Error::Http(e));
97                    }
98                    Err(e) => return Err(e),
99                };
100
101                debug!("Client handshake done.");
102                let websocket =
103                    WebSocket::from_partially_read(stream, tail, Role::Client, self.config);
104                ProcessingResult::Done((websocket, result))
105            }
106        })
107    }
108}
109
110/// Verifies and generates a client WebSocket request from the original request and extracts a WebSocket key from it.
111pub fn generate_request(mut request: Request) -> Result<(Vec<u8>, String)> {
112    let mut req = Vec::new();
113    write!(
114        req,
115        "GET {path} {version:?}\r\n",
116        path = request.uri().path_and_query().ok_or(Error::Url(UrlError::NoPathOrQuery))?.as_str(),
117        version = request.version()
118    )
119    .unwrap();
120
121    // Headers that must be present in a correct request.
122    const KEY_HEADERNAME: &str = "Sec-WebSocket-Key";
123    const WEBSOCKET_HEADERS: [&str; 5] =
124        ["Host", "Connection", "Upgrade", "Sec-WebSocket-Version", KEY_HEADERNAME];
125
126    // We must extract a WebSocket key from a properly formed request or fail if it's not present.
127    let key = request
128        .headers()
129        .get(KEY_HEADERNAME)
130        .ok_or_else(|| {
131            Error::Protocol(ProtocolError::InvalidHeader(
132                HeaderName::from_bytes(KEY_HEADERNAME.as_bytes()).unwrap(),
133            ))
134        })?
135        .to_str()?
136        .to_owned();
137
138    // We must check that all necessary headers for a valid request are present. Note that we have to
139    // deal with the fact that some apps seem to have a case-sensitive check for headers which is not
140    // correct and should not considered the correct behavior, but it seems like some apps ignore it.
141    // `http` by default writes all headers in lower-case which is fine (and does not violate the RFC)
142    // but some servers seem to be poorely written and ignore RFC.
143    //
144    // See similar problem in `hyper`: https://github.com/hyperium/hyper/issues/1492
145    let headers = request.headers_mut();
146    for &header in &WEBSOCKET_HEADERS {
147        let value = headers.remove(header).ok_or_else(|| {
148            Error::Protocol(ProtocolError::InvalidHeader(
149                HeaderName::from_bytes(header.as_bytes()).unwrap(),
150            ))
151        })?;
152        write!(req, "{header}: {value}\r\n", header = header, value = value.to_str()?).unwrap();
153    }
154
155    // Now we must ensure that the headers that we've written once are not anymore present in the map.
156    // If they do, then the request is invalid (some headers are duplicated there for some reason).
157    let insensitive: Vec<String> =
158        WEBSOCKET_HEADERS.iter().map(|h| h.to_ascii_lowercase()).collect();
159    for (k, v) in headers {
160        let mut name = k.as_str();
161
162        // We have already written the necessary headers once (above) and removed them from the map.
163        // If we encounter them again, then the request is considered invalid and error is returned.
164        // Note that we can't use `.contains()`, since `&str` does not coerce to `&String` in Rust.
165        if insensitive.iter().any(|x| x == name) {
166            return Err(Error::Protocol(ProtocolError::InvalidHeader(k.clone())));
167        }
168
169        // Relates to the issue of some servers treating headers in a case-sensitive way, please see:
170        // https://github.com/snapview/tungstenite-rs/pull/119 (original fix of the problem)
171        if name == "sec-websocket-protocol" {
172            name = "Sec-WebSocket-Protocol";
173        }
174
175        if name == "origin" {
176            name = "Origin";
177        }
178
179        writeln!(req, "{}: {}\r", name, v.to_str()?).unwrap();
180    }
181
182    writeln!(req, "\r").unwrap();
183    trace!("Request: {:?}", String::from_utf8_lossy(&req));
184    Ok((req, key))
185}
186
187fn extract_subprotocols_from_request(request: &Request) -> Result<Option<Vec<String>>> {
188    if let Some(subprotocols) = request.headers().get("Sec-WebSocket-Protocol") {
189        Ok(Some(subprotocols.to_str()?.split(',').map(|s| s.trim().to_string()).collect()))
190    } else {
191        Ok(None)
192    }
193}
194
195/// Information for handshake verification.
196#[derive(Debug)]
197struct VerifyData {
198    /// Accepted server key.
199    accept_key: String,
200
201    /// Accepted subprotocols
202    subprotocols: Option<Vec<String>>,
203}
204
205impl VerifyData {
206    pub fn verify_response(&self, response: Response) -> Result<Response> {
207        // 1. If the status code received from the server is not 101, the
208        // client handles the response per HTTP [RFC2616] procedures. (RFC 6455)
209        if response.status() != StatusCode::SWITCHING_PROTOCOLS {
210            return Err(Error::Http(response));
211        }
212
213        let headers = response.headers();
214
215        // 2. If the response lacks an |Upgrade| header field or the |Upgrade|
216        // header field contains a value that is not an ASCII case-
217        // insensitive match for the value "websocket", the client MUST
218        // _Fail the WebSocket Connection_. (RFC 6455)
219        if !headers
220            .get("Upgrade")
221            .and_then(|h| h.to_str().ok())
222            .map(|h| h.eq_ignore_ascii_case("websocket"))
223            .unwrap_or(false)
224        {
225            return Err(Error::Protocol(ProtocolError::MissingUpgradeWebSocketHeader));
226        }
227        // 3.  If the response lacks a |Connection| header field or the
228        // |Connection| header field doesn't contain a token that is an
229        // ASCII case-insensitive match for the value "Upgrade", the client
230        // MUST _Fail the WebSocket Connection_. (RFC 6455)
231        if !headers
232            .get("Connection")
233            .and_then(|h| h.to_str().ok())
234            .map(|h| h.eq_ignore_ascii_case("Upgrade"))
235            .unwrap_or(false)
236        {
237            return Err(Error::Protocol(ProtocolError::MissingConnectionUpgradeHeader));
238        }
239        // 4.  If the response lacks a |Sec-WebSocket-Accept| header field or
240        // the |Sec-WebSocket-Accept| contains a value other than the
241        // base64-encoded SHA-1 of ... the client MUST _Fail the WebSocket
242        // Connection_. (RFC 6455)
243        if !headers.get("Sec-WebSocket-Accept").map(|h| h == &self.accept_key).unwrap_or(false) {
244            return Err(Error::Protocol(ProtocolError::SecWebSocketAcceptKeyMismatch));
245        }
246        // 5.  If the response includes a |Sec-WebSocket-Extensions| header
247        // field and this header field indicates the use of an extension
248        // that was not present in the client's handshake (the server has
249        // indicated an extension not requested by the client), the client
250        // MUST _Fail the WebSocket Connection_. (RFC 6455)
251        // TODO
252
253        // 6.  If the response includes a |Sec-WebSocket-Protocol| header field
254        // and this header field indicates the use of a subprotocol that was
255        // not present in the client's handshake (the server has indicated a
256        // subprotocol not requested by the client), the client MUST _Fail
257        // the WebSocket Connection_. (RFC 6455)
258        if headers.get("Sec-WebSocket-Protocol").is_none() && self.subprotocols.is_some() {
259            return Err(Error::Protocol(ProtocolError::SecWebSocketSubProtocolError(
260                SubProtocolError::NoSubProtocol,
261            )));
262        }
263
264        if headers.get("Sec-WebSocket-Protocol").is_some() && self.subprotocols.is_none() {
265            return Err(Error::Protocol(ProtocolError::SecWebSocketSubProtocolError(
266                SubProtocolError::ServerSentSubProtocolNoneRequested,
267            )));
268        }
269
270        if let Some(returned_subprotocol) = headers.get("Sec-WebSocket-Protocol") {
271            if let Some(accepted_subprotocols) = &self.subprotocols {
272                if !accepted_subprotocols.contains(&returned_subprotocol.to_str()?.to_string()) {
273                    return Err(Error::Protocol(ProtocolError::SecWebSocketSubProtocolError(
274                        SubProtocolError::InvalidSubProtocol,
275                    )));
276                }
277            }
278        }
279
280        Ok(response)
281    }
282}
283
284impl TryParse for Response {
285    fn try_parse(buf: &[u8]) -> Result<Option<(usize, Self)>> {
286        let mut hbuffer = [httparse::EMPTY_HEADER; MAX_HEADERS];
287        let mut req = httparse::Response::new(&mut hbuffer);
288        Ok(match req.parse(buf)? {
289            Status::Partial => None,
290            Status::Complete(size) => Some((size, Response::from_httparse(req)?)),
291        })
292    }
293}
294
295impl<'h, 'b: 'h> FromHttparse<httparse::Response<'h, 'b>> for Response {
296    fn from_httparse(raw: httparse::Response<'h, 'b>) -> Result<Self> {
297        if raw.version.expect("Bug: no HTTP version") < /*1.*/1 {
298            return Err(Error::Protocol(ProtocolError::WrongHttpVersion));
299        }
300
301        let headers = HeaderMap::from_httparse(raw.headers)?;
302
303        let mut response = Response::new(None);
304        *response.status_mut() = StatusCode::from_u16(raw.code.expect("Bug: no HTTP status code"))?;
305        *response.headers_mut() = headers;
306        // TODO: httparse only supports HTTP 0.9/1.0/1.1 but not HTTP 2.0
307        // so the only valid value we could get in the response would be 1.1.
308        *response.version_mut() = http::Version::HTTP_11;
309
310        Ok(response)
311    }
312}
313
314/// Generate a random key for the `Sec-WebSocket-Key` header.
315pub fn generate_key() -> String {
316    // a base64-encoded (see Section 4 of [RFC4648]) value that,
317    // when decoded, is 16 bytes in length (RFC 6455)
318    let r: [u8; 16] = rand::random();
319    data_encoding::BASE64.encode(&r)
320}
321
322#[cfg(test)]
323mod tests {
324    use super::{super::machine::TryParse, generate_key, generate_request, Response};
325    use crate::client::IntoClientRequest;
326
327    #[test]
328    fn random_keys() {
329        let k1 = generate_key();
330        println!("Generated random key 1: {k1}");
331        let k2 = generate_key();
332        println!("Generated random key 2: {k2}");
333        assert_ne!(k1, k2);
334        assert_eq!(k1.len(), k2.len());
335        assert_eq!(k1.len(), 24);
336        assert_eq!(k2.len(), 24);
337        assert!(k1.ends_with("=="));
338        assert!(k2.ends_with("=="));
339        assert!(k1[..22].find('=').is_none());
340        assert!(k2[..22].find('=').is_none());
341    }
342
343    fn construct_expected(host: &str, key: &str) -> Vec<u8> {
344        format!(
345            "\
346            GET /getCaseCount HTTP/1.1\r\n\
347            Host: {host}\r\n\
348            Connection: Upgrade\r\n\
349            Upgrade: websocket\r\n\
350            Sec-WebSocket-Version: 13\r\n\
351            Sec-WebSocket-Key: {key}\r\n\
352            \r\n"
353        )
354        .into_bytes()
355    }
356
357    #[test]
358    fn request_formatting() {
359        let request = "ws://localhost/getCaseCount".into_client_request().unwrap();
360        let (request, key) = generate_request(request).unwrap();
361        let correct = construct_expected("localhost", &key);
362        assert_eq!(&request[..], &correct[..]);
363    }
364
365    #[test]
366    fn request_formatting_with_host() {
367        let request = "wss://localhost:9001/getCaseCount".into_client_request().unwrap();
368        let (request, key) = generate_request(request).unwrap();
369        let correct = construct_expected("localhost:9001", &key);
370        assert_eq!(&request[..], &correct[..]);
371    }
372
373    #[test]
374    fn request_formatting_with_at() {
375        let request = "wss://user:pass@localhost:9001/getCaseCount".into_client_request().unwrap();
376        let (request, key) = generate_request(request).unwrap();
377        let correct = construct_expected("localhost:9001", &key);
378        assert_eq!(&request[..], &correct[..]);
379    }
380
381    #[test]
382    fn response_parsing() {
383        const DATA: &[u8] = b"HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n\r\n";
384        let (_, resp) = Response::try_parse(DATA).unwrap().unwrap();
385        assert_eq!(resp.status(), http::StatusCode::OK);
386        assert_eq!(resp.headers().get("Content-Type").unwrap(), &b"text/html"[..],);
387    }
388
389    #[test]
390    fn invalid_custom_request() {
391        let request = http::Request::builder().method("GET").body(()).unwrap();
392        assert!(generate_request(request).is_err());
393    }
394}
tungstenite/handshake/client.rs

tungstenite/handshake/
client.rs
