tungstenite/handshake/
client.rs

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

tungstenite/handshake/
client.rs
