tungstenite/handshake/
mod.rs

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
//! WebSocket handshake control.

pub mod client;
pub mod headers;
pub mod machine;
pub mod server;

use std::{
    error::Error as ErrorTrait,
    fmt,
    io::{Read, Write},
};

use sha1::{Digest, Sha1};

use self::machine::{HandshakeMachine, RoundResult, StageResult, TryParse};
use crate::error::Error;

/// A WebSocket handshake.
#[derive(Debug)]
pub struct MidHandshake<Role: HandshakeRole> {
    role: Role,
    machine: HandshakeMachine<Role::InternalStream>,
}

impl<Role: HandshakeRole> MidHandshake<Role> {
    /// Allow access to machine
    pub fn get_ref(&self) -> &HandshakeMachine<Role::InternalStream> {
        &self.machine
    }

    /// Allow mutable access to machine
    pub fn get_mut(&mut self) -> &mut HandshakeMachine<Role::InternalStream> {
        &mut self.machine
    }

    /// Restarts the handshake process.
    pub fn handshake(mut self) -> Result<Role::FinalResult, HandshakeError<Role>> {
        let mut mach = self.machine;
        loop {
            mach = match mach.single_round()? {
                RoundResult::WouldBlock(m) => {
                    return Err(HandshakeError::Interrupted(MidHandshake { machine: m, ..self }))
                }
                RoundResult::Incomplete(m) => m,
                RoundResult::StageFinished(s) => match self.role.stage_finished(s)? {
                    ProcessingResult::Continue(m) => m,
                    ProcessingResult::Done(result) => return Ok(result),
                },
            }
        }
    }
}

/// A handshake result.
pub enum HandshakeError<Role: HandshakeRole> {
    /// Handshake was interrupted (would block).
    Interrupted(MidHandshake<Role>),
    /// Handshake failed.
    Failure(Error),
}

impl<Role: HandshakeRole> fmt::Debug for HandshakeError<Role> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            HandshakeError::Interrupted(_) => write!(f, "HandshakeError::Interrupted(...)"),
            HandshakeError::Failure(ref e) => write!(f, "HandshakeError::Failure({:?})", e),
        }
    }
}

impl<Role: HandshakeRole> fmt::Display for HandshakeError<Role> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            HandshakeError::Interrupted(_) => write!(f, "Interrupted handshake (WouldBlock)"),
            HandshakeError::Failure(ref e) => write!(f, "{}", e),
        }
    }
}

impl<Role: HandshakeRole> ErrorTrait for HandshakeError<Role> {}

impl<Role: HandshakeRole> From<Error> for HandshakeError<Role> {
    fn from(err: Error) -> Self {
        HandshakeError::Failure(err)
    }
}

/// Handshake role.
pub trait HandshakeRole {
    #[doc(hidden)]
    type IncomingData: TryParse;
    #[doc(hidden)]
    type InternalStream: Read + Write;
    #[doc(hidden)]
    type FinalResult;
    #[doc(hidden)]
    fn stage_finished(
        &mut self,
        finish: StageResult<Self::IncomingData, Self::InternalStream>,
    ) -> Result<ProcessingResult<Self::InternalStream, Self::FinalResult>, Error>;
}

/// Stage processing result.
#[doc(hidden)]
#[derive(Debug)]
pub enum ProcessingResult<Stream, FinalResult> {
    Continue(HandshakeMachine<Stream>),
    Done(FinalResult),
}

/// Derive the `Sec-WebSocket-Accept` response header from a `Sec-WebSocket-Key` request header.
///
/// This function can be used to perform a handshake before passing a raw TCP stream to
/// [`WebSocket::from_raw_socket`][crate::protocol::WebSocket::from_raw_socket].
pub fn derive_accept_key(request_key: &[u8]) -> String {
    // ... field is constructed by concatenating /key/ ...
    // ... with the string "258EAFA5-E914-47DA-95CA-C5AB0DC85B11" (RFC 6455)
    const WS_GUID: &[u8] = b"258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
    let mut sha1 = Sha1::default();
    sha1.update(request_key);
    sha1.update(WS_GUID);
    data_encoding::BASE64.encode(&sha1.finalize())
}

#[cfg(test)]
mod tests {
    use super::derive_accept_key;

    #[test]
    fn key_conversion() {
        // example from RFC 6455
        assert_eq!(derive_accept_key(b"dGhlIHNhbXBsZSBub25jZQ=="), "s3pPLMBiTxaQ9kYGzzhZRbK+xOo=");
    }
}