Struct LazyConfigAcceptor 

pub struct LazyConfigAcceptor<IO> {
    acceptor: Acceptor,
    io: Option<IO>,
    alert: Option<(Error, AcceptedAlert)>,
}

A future for reading a ClientHello from io without committing to a ServerConfig.

Awaiting it yields a StartHandshake, which exposes the ClientHello (for example, to choose a config based on SNI) and performs the rest of the handshake via StartHandshake::into_stream().

Fields

acceptor: Acceptor

io: Option<IO>

alert: Option<(Error, AcceptedAlert)>

Implementations

impl<IO> LazyConfigAcceptor<IO>

where IO: AsyncRead + AsyncWrite + Unpin,

pub fn new(acceptor: Acceptor, io: IO) -> Self

Returns a new LazyConfigAcceptor that reads a ClientHello from io.

You likely want to wrap awaiting the acceptor in a timeout to bound how long the peer may take to send the ClientHello.

Note that awaiting the acceptor is only the first half of the handshake and StartHandshake::into_stream() performs the rest.

To bound the time for the complete handshake, share one deadline across both awaits (for example with tokio::time::timeout_at) rather than giving each its own timeout.

If a timeout elapses before the ClientHello arrives, Self::take_io() can recover the io, for example to answer the peer in plaintext before closing.

pub fn take_io(&mut self) -> Option<IO>

Takes back the client connection. Will return None if called more than once or if the connection has been accepted.

Example

use tokio::io::AsyncWriteExt;
let listener = tokio::net::TcpListener::bind("127.0.0.1:4443").await.unwrap();
let (stream, _) = listener.accept().await.unwrap();

let acceptor = tokio_rustls::LazyConfigAcceptor::new(rustls::server::Acceptor::default(), stream);
tokio::pin!(acceptor);

match acceptor.as_mut().await {
    Ok(start) => {
        let clientHello = start.client_hello();
        let config = choose_server_config(clientHello);
        let stream = start.into_stream(config).await.unwrap();
        // Proceed with handling the ServerConnection...
    }
    Err(err) => {
        if let Some(mut stream) = acceptor.take_io() {
            stream
                .write_all(
                    format!("HTTP/1.1 400 Invalid Input\r\n\r\n\r\n{:?}\n", err)
                        .as_bytes()
                )
                .await
                .unwrap();
        }
    }
}

Trait Implementations

impl<IO> Future for LazyConfigAcceptor<IO>

where IO: AsyncRead + AsyncWrite + Unpin,

type Output = Result<StartHandshake<IO>, Error>

The type of value produced on completion.

fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output>

Attempts to resolve the future to a final value, registering the current task for wakeup if the value is not yet available.