rama-tls 0.3.0

rama TLS-agnostic types and utilities
Documentation 
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use std::time::Duration;

use rama_core::{
    Service,
    error::{BoxError, ErrorContext},
    io::{
        HeapReader, PeekIoProvider, PrefixedIo,
        peek::{PeekOutput, peek_input_until, peek_input_until_with_offset},
    },
    service::RejectService,
    telemetry::tracing,
};
use rama_utils::octets::kib;
use tokio::time::Instant;

use crate::client::{ClientHello, parse_client_hello_handshake};

use super::NoTlsRejectError;

/// A peek [`Service`] which returns the [`ClientHello`] to the inner
/// service for tls-detected traffic, and otherwise make use of the Reject service.
///
/// The difference with [`SniRouter`] is that the entire
/// [`ClientHello`] is parsed and returned instead of just the SNI. Use the router
/// in case all you care about is the SNI, given it is more efficient.
///
/// By default non-tls traffic is rejected using [`RejectService`].
/// Use [`PeekTlsClientHelloService::with_fallback`] to configure the fallback service.
///
/// Use the standalone [`peek_client_hello_from_input`] function if you prefer
/// this is as a standalone function instead.
///
/// [`SniRouter`]: super::SniRouter
#[derive(Debug, Clone)]
pub struct PeekTlsClientHelloService<S, F = RejectService<(), NoTlsRejectError>> {
    service: S,
    fallback: F,
    peek_timeout: Option<Duration>,
}

impl<S> PeekTlsClientHelloService<S> {
    /// Create a new [`PeekTlsClientHelloService`].
    pub fn new(service: S) -> Self {
        Self {
            service,
            fallback: RejectService::new(NoTlsRejectError),
            peek_timeout: None,
        }
    }

    /// Attach a fallback [`Service`] to this [`PeekTlsClientHelloService`].
    ///
    /// Used in case the traffic is not Tls traffic (defined by the first bytes).
    pub fn with_fallback<F>(self, fallback: F) -> PeekTlsClientHelloService<S, F> {
        PeekTlsClientHelloService {
            service: self.service,
            fallback,
            peek_timeout: self.peek_timeout,
        }
    }
}

impl<S, F> PeekTlsClientHelloService<S, F> {
    rama_utils::macros::generate_set_and_with! {
        /// Set the peek window to timeout on
        pub fn peek_timeout(mut self, peek_timeout: Option<Duration>) -> Self {
            self.peek_timeout = peek_timeout;
            self
        }
    }
}

/// Functional API to try to peek TLS:CH from an existing I/O input,
/// returning the stream as-is with the read data prefixed from memory.
///
/// Use [`PeekTlsClientHelloService`] if you prefer it as a rama [`Service`] instead.
pub async fn peek_client_hello_from_input<PeekableInput>(
    mut input: PeekableInput,
    timeout: Option<Duration>,
) -> Result<
    (
        PeekableInput::Mapped<TlsClientHelloPrefixedIo<PeekableInput::PeekIo>>,
        Option<ClientHello>,
    ),
    std::io::Error,
>
where
    PeekableInput: PeekIoProvider<PeekIo: Unpin>,
{
    let mut peek_buf = [0u8; TLS_HEADER_PEEK_LEN];
    let peekable_io = input.peek_io_mut();

    let start = Instant::now();

    let PeekOutput { data, peek_size } =
        peek_input_until(peekable_io, &mut peek_buf, timeout, |buffer| {
            if buffer.len() == TLS_HEADER_PEEK_LEN
                && matches!(buffer, [0x16, 0x03, 0x00..=0x04, ..])
            {
                Some(())
            } else {
                None
            }
        })
        .await;

    let is_tls = data.is_some();
    tracing::trace!("tls prefix header read (is tls: {is_tls})");

    if !is_tls {
        if TLS_HEADER_PEEK_LEN.saturating_sub(peek_size) > 0 {
            tracing::trace!(
                "move tls peek buffer cursor due to reading not enough (read: {peek_size})"
            );
        }

        let prefix_data = HeapReader::from(&peek_buf[..peek_size.min(TLS_HEADER_PEEK_LEN)]);
        let peeked_input = input.map_peek_io(|io| PrefixedIo::new(prefix_data, io));

        tracing::trace!("return early for non-tls traffic: missing peek header");
        return Ok((peeked_input, None));
    }

    let n = ((peek_buf[3] as usize) << 8) | (peek_buf[4] as usize);
    // Size the peek buffer to the declared TLS record body length,
    // bounded by the TLS record-size ceiling (RFC 8446 §5.1: a record
    // payload is at most 2^14 bytes). The previous 2 KiB cap silently
    // truncated modern ClientHellos (Firefox/Chrome with post-quantum
    // key shares, GREASE, ALPS, full cipher lists routinely exceed
    // 2 KiB) — combined with a parser that masked a truncated read as
    // "no extensions", that made us mirror a bare default ClientHello
    // and get rejected by SNI-routed upstreams. The bound still guards
    // against a malformed huge length triggering an unbounded alloc.
    const MAX_TLS_RECORD_BODY: usize = kib(16);
    let record_size = (n + TLS_HEADER_PEEK_LEN).min(MAX_TLS_RECORD_BODY + TLS_HEADER_PEEK_LEN);

    let mut v = vec![0u8; record_size];
    v[..TLS_HEADER_PEEK_LEN].copy_from_slice(&peek_buf[..]);

    let new_timeout = timeout.map(|t| t.saturating_sub(start.elapsed()));

    let PeekOutput {
        data: maybe_client_hello,
        peek_size,
    } = peek_input_until_with_offset(
        peekable_io,
        &mut v,
        TLS_HEADER_PEEK_LEN,
        new_timeout,
        |buffer| {
            let n = buffer.len();
            parse_client_hello_handshake(buffer)
                .inspect_err(|err| {
                    tracing::debug!("failed parse client hello handshake ({n}) byte(s): {err}",)
                })
                .ok()
        },
    )
    .await;

    // `saturating_sub`: `peek_input_until_with_offset` is expected to return
    // a `peek_size` greater than or equal to the offset we passed in
    // (`TLS_HEADER_PEEK_LEN`), but treating the boundary defensively matches
    // the convention used at line 110 above and avoids an arithmetic
    // underflow if that contract is ever broken.
    let new_peek_size = peek_size.saturating_sub(TLS_HEADER_PEEK_LEN);
    if new_peek_size != n {
        tracing::trace!(
            peek_size = new_peek_size,
            expected_peek_size = n,
            "unexpected read size for client hello handshake data: try regardless..."
        );
    }

    let prefix_data = HeapReader::from(v);
    let peeked_input = input.map_peek_io(|io| PrefixedIo::new(prefix_data, io));

    Ok((peeked_input, maybe_client_hello))
}

impl<PeekableInput, Output, S, F> Service<PeekableInput> for PeekTlsClientHelloService<S, F>
where
    PeekableInput: PeekIoProvider<PeekIo: Unpin>,
    Output: Send + 'static,
    S: Service<
            InputWithClientHello<
                PeekableInput::Mapped<TlsClientHelloPrefixedIo<PeekableInput::PeekIo>>,
            >,
            Output = Output,
            Error: Into<BoxError>,
        >,
    F: Service<
            PeekableInput::Mapped<TlsClientHelloPrefixedIo<PeekableInput::PeekIo>>,
            Output = Output,
            Error: Into<BoxError>,
        >,
{
    type Output = Output;
    type Error = BoxError;

    async fn serve(&self, input: PeekableInput) -> Result<Self::Output, Self::Error> {
        let (peeked_input, maybe_client_hello) =
            peek_client_hello_from_input(input, self.peek_timeout)
                .await
                .context("I/O error while peeking TLS:CH from existing input")?;

        if let Some(client_hello) = maybe_client_hello {
            self.service
                .serve(InputWithClientHello {
                    input: peeked_input,
                    client_hello,
                })
                .await
                .map_err(Into::into)
        } else {
            self.fallback.serve(peeked_input).await.map_err(Into::into)
        }
    }
}

const TLS_HEADER_PEEK_LEN: usize = 5;

/// [`PrefixedIo`] alias used by [`PeekTlsClientHelloService`].
pub type TlsClientHelloPrefixedIo<S> = PrefixedIo<HeapReader, S>;

/// An `input` with a Client Hello (tls) attached to it,
/// usually used in combination with [`PeekTlsClientHelloService`].
#[derive(Debug, Clone)]
pub struct InputWithClientHello<Input> {
    pub input: Input,
    pub client_hello: ClientHello,
}

#[cfg(test)]
mod test {
    use rama_core::{
        ServiceInput,
        service::{RejectError, service_fn},
    };
    use std::convert::Infallible;
    use tokio::io::AsyncReadExt as _;

    use rama_core::io::Io;

    use super::*;

    const CH_ONE_ONE_ONE_ONE: &[u8] = &[
        0x16, 0x03, 0x01, 0x02, 0x00, 0x01, 0x00, 0x01, 0xfc, 0x03, 0x03, 0x02, 0x15, 0xfd, 0xe2,
        0x92, 0xc0, 0x46, 0x9f, 0x92, 0xbe, 0xd7, 0xe9, 0x1a, 0x3c, 0x50, 0x5e, 0x55, 0x49, 0x17,
        0xa6, 0xf8, 0xa5, 0xca, 0xa4, 0x6d, 0x60, 0xcc, 0xea, 0xf7, 0x25, 0xf0, 0x6e, 0x20, 0x41,
        0x20, 0x18, 0x66, 0x5c, 0xae, 0x08, 0xb0, 0x10, 0x96, 0x3c, 0xad, 0xb4, 0x13, 0xe1, 0x92,
        0xce, 0x96, 0xad, 0x9d, 0x45, 0x05, 0xb7, 0xa6, 0x4c, 0x01, 0x71, 0x08, 0x74, 0x0d, 0x1f,
        0x35, 0x00, 0x2a, 0x3a, 0x3a, 0x13, 0x01, 0x13, 0x02, 0x13, 0x03, 0xc0, 0x2c, 0xc0, 0x2b,
        0xcc, 0xa9, 0xc0, 0x30, 0xc0, 0x2f, 0xcc, 0xa8, 0xc0, 0x0a, 0xc0, 0x09, 0xc0, 0x14, 0xc0,
        0x13, 0x00, 0x9d, 0x00, 0x9c, 0x00, 0x35, 0x00, 0x2f, 0xc0, 0x08, 0xc0, 0x12, 0x00, 0x0a,
        0x01, 0x00, 0x01, 0x89, 0xda, 0xda, 0x00, 0x00, 0x00, 0x00, 0x00, 0x14, 0x00, 0x12, 0x00,
        0x00, 0x0f, 0x6f, 0x6e, 0x65, 0x2e, 0x6f, 0x6e, 0x65, 0x2e, 0x6f, 0x6e, 0x65, 0x2e, 0x6f,
        0x6e, 0x65, 0x00, 0x17, 0x00, 0x00, 0xff, 0x01, 0x00, 0x01, 0x00, 0x00, 0x0a, 0x00, 0x0c,
        0x00, 0x0a, 0xfa, 0xfa, 0x00, 0x1d, 0x00, 0x17, 0x00, 0x18, 0x00, 0x19, 0x00, 0x0b, 0x00,
        0x02, 0x01, 0x00, 0x00, 0x05, 0x00, 0x05, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0d, 0x00,
        0x16, 0x00, 0x14, 0x04, 0x03, 0x08, 0x04, 0x04, 0x01, 0x05, 0x03, 0x08, 0x05, 0x08, 0x05,
        0x05, 0x01, 0x08, 0x06, 0x06, 0x01, 0x02, 0x01, 0x00, 0x12, 0x00, 0x00, 0x00, 0x33, 0x00,
        0x2b, 0x00, 0x29, 0xfa, 0xfa, 0x00, 0x01, 0x00, 0x00, 0x1d, 0x00, 0x20, 0x7c, 0xe1, 0xc6,
        0xc2, 0x01, 0x69, 0x42, 0xba, 0x2b, 0xec, 0x07, 0x2f, 0x04, 0xbd, 0xb6, 0x2a, 0x7e, 0x04,
        0x6b, 0x96, 0x98, 0x51, 0x4e, 0x80, 0xb3, 0x2a, 0x4c, 0x4f, 0x1f, 0x39, 0x82, 0x2b, 0x00,
        0x2d, 0x00, 0x02, 0x01, 0x01, 0x00, 0x2b, 0x00, 0x0b, 0x0a, 0x6a, 0x6a, 0x03, 0x04, 0x03,
        0x03, 0x03, 0x02, 0x03, 0x01, 0x00, 0x1b, 0x00, 0x03, 0x02, 0x00, 0x01, 0x3a, 0x3a, 0x00,
        0x01, 0x00, 0x00, 0x15, 0x00, 0xd3, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    ];

    const TLS_BUT_NO_SNI: &[u8] = &[
        0x16, 0x03, 0x01, 0x02, 0x00, 0x01, 0x00, 0x01, 0xfc, 0x03, 0x03, 0x28, 0x5b, 0x8f, 0x90,
        0x22, 0x2a, 0x90, 0x95, 0x89, 0xa9, 0x62, 0x1f, 0xdb, 0x68, 0xbe, 0x4c, 0x0e, 0xdf, 0xe4,
        0x76, 0x50, 0x48, 0xa5, 0x40, 0x56, 0x5f, 0x9a, 0xba, 0x19, 0x29, 0x66, 0xdd, 0x20, 0x7a,
        0x7f, 0x7e, 0xc7, 0xbd, 0xfb, 0x88, 0x07, 0xd9, 0xf5, 0x99, 0xfa, 0xf3, 0x0d, 0x37, 0x30,
        0x52, 0x4d, 0x44, 0xe4, 0x26, 0xc0, 0xd1, 0x9a, 0xcd, 0x78, 0xf6, 0x7a, 0xf1, 0x7a, 0x66,
        0xe1, 0x00, 0x3e, 0x13, 0x02, 0x13, 0x03, 0x13, 0x01, 0xc0, 0x2c, 0xc0, 0x30, 0x00, 0x9f,
        0xcc, 0xa9, 0xcc, 0xa8, 0xcc, 0xaa, 0xc0, 0x2b, 0xc0, 0x2f, 0x00, 0x9e, 0xc0, 0x24, 0xc0,
        0x28, 0x00, 0x6b, 0xc0, 0x23, 0xc0, 0x27, 0x00, 0x67, 0xc0, 0x0a, 0xc0, 0x14, 0x00, 0x39,
        0xc0, 0x09, 0xc0, 0x13, 0x00, 0x33, 0x00, 0x9d, 0x00, 0x9c, 0x00, 0x3d, 0x00, 0x3c, 0x00,
        0x35, 0x00, 0x2f, 0x00, 0xff, 0x01, 0x00, 0x01, 0x75, 0x00, 0x0b, 0x00, 0x04, 0x03, 0x00,
        0x01, 0x02, 0x00, 0x0a, 0x00, 0x16, 0x00, 0x14, 0x00, 0x1d, 0x00, 0x17, 0x00, 0x1e, 0x00,
        0x19, 0x00, 0x18, 0x01, 0x00, 0x01, 0x01, 0x01, 0x02, 0x01, 0x03, 0x01, 0x04, 0x00, 0x10,
        0x00, 0x0e, 0x00, 0x0c, 0x02, 0x68, 0x32, 0x08, 0x68, 0x74, 0x74, 0x70, 0x2f, 0x31, 0x2e,
        0x31, 0x00, 0x16, 0x00, 0x00, 0x00, 0x17, 0x00, 0x00, 0x00, 0x31, 0x00, 0x00, 0x00, 0x0d,
        0x00, 0x2a, 0x00, 0x28, 0x04, 0x03, 0x05, 0x03, 0x06, 0x03, 0x08, 0x07, 0x08, 0x08, 0x08,
        0x09, 0x08, 0x0a, 0x08, 0x0b, 0x08, 0x04, 0x08, 0x05, 0x08, 0x06, 0x04, 0x01, 0x05, 0x01,
        0x06, 0x01, 0x03, 0x03, 0x03, 0x01, 0x03, 0x02, 0x04, 0x02, 0x05, 0x02, 0x06, 0x02, 0x00,
        0x2b, 0x00, 0x05, 0x04, 0x03, 0x04, 0x03, 0x03, 0x00, 0x2d, 0x00, 0x02, 0x01, 0x01, 0x00,
        0x33, 0x00, 0x26, 0x00, 0x24, 0x00, 0x1d, 0x00, 0x20, 0xe0, 0xb9, 0xfb, 0x5a, 0xd5, 0x60,
        0x30, 0x39, 0xad, 0xfb, 0xd3, 0x94, 0xa2, 0xff, 0x08, 0x71, 0x9b, 0xcc, 0x6f, 0xbe, 0x9e,
        0xcc, 0x7b, 0xad, 0x3c, 0xd0, 0xde, 0xe8, 0x3e, 0x5d, 0xba, 0x6b, 0x00, 0x15, 0x00, 0xca,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    ];

    #[tokio::test]
    async fn test_client_hello_peek_service() {
        let tls_service = service_fn(async |input: InputWithClientHello<_>| {
            let sni = input
                .client_hello
                .ext_server_name()
                .map(ToString::to_string);
            Ok::<_, Infallible>(sni)
        });
        let plain_service = service_fn(async || Ok::<_, Infallible>(Some("plain".to_owned())));

        let peek_tls_svc = PeekTlsClientHelloService::new(tls_service).with_fallback(plain_service);
        let response = peek_tls_svc
            .serve(ServiceInput::new(std::io::Cursor::new(b"".to_vec())))
            .await
            .unwrap();
        assert_eq!(Some("plain".to_owned()), response);

        let response = peek_tls_svc
            .serve(ServiceInput::new(std::io::Cursor::new(
                CH_ONE_ONE_ONE_ONE.to_vec(),
            )))
            .await
            .unwrap();
        assert_eq!(Some("one.one.one.one".to_owned()), response);

        let response = peek_tls_svc
            .serve(ServiceInput::new(std::io::Cursor::new(b"foo".to_vec())))
            .await
            .unwrap();
        assert_eq!(Some("plain".to_owned()), response);

        let response = peek_tls_svc
            .serve(ServiceInput::new(std::io::Cursor::new(b"foobar".to_vec())))
            .await
            .unwrap();
        assert_eq!(Some("plain".to_owned()), response);

        let response = peek_tls_svc
            .serve(ServiceInput::new(std::io::Cursor::new(
                TLS_BUT_NO_SNI.to_vec(),
            )))
            .await
            .unwrap();
        assert_eq!(None, response);
    }

    #[tokio::test]
    async fn test_peek_router_read_eof() {
        async fn tls_service_fn(
            InputWithClientHello {
                mut input,
                client_hello,
            }: InputWithClientHello<impl Io + Unpin>,
        ) -> Result<&'static str, BoxError> {
            let mut v = Vec::default();
            _ = input.read_to_end(&mut v).await?;
            assert_eq!(CH_ONE_ONE_ONE_ONE, v);
            assert!(client_hello.ext_server_name().is_some());
            assert_eq!(
                "one.one.one.one",
                client_hello.ext_server_name().unwrap().to_string()
            );
            Ok("ok")
        }
        let tls_service = service_fn(tls_service_fn);

        let peek_tls_svc =
            PeekTlsClientHelloService::new(tls_service).with_fallback(RejectService::<
                &'static str,
                RejectError,
            >::new(
                RejectError::default()
            ));

        let response = peek_tls_svc
            .serve(ServiceInput::new(std::io::Cursor::new(
                CH_ONE_ONE_ONE_ONE.to_vec(),
            )))
            .await
            .unwrap();
        assert_eq!("ok", response);
    }

    #[tokio::test]
    async fn test_peek_router_read_no_tls_eof() {
        let cases = ["", "foo", "abcd", "abcde", "foobarbazbananas"];
        for content in cases {
            async fn tls_service_fn() -> Result<Vec<u8>, BoxError> {
                Ok("tls".as_bytes().to_vec())
            }
            let tls_service = service_fn(tls_service_fn);

            async fn plain_service_fn(mut stream: impl Io + Unpin) -> Result<Vec<u8>, BoxError> {
                let mut v = Vec::default();
                _ = stream.read_to_end(&mut v).await?;
                Ok(v)
            }
            let plain_service = service_fn(plain_service_fn);

            let peek_tls_svc =
                PeekTlsClientHelloService::new(tls_service).with_fallback(plain_service);

            let response = peek_tls_svc
                .serve(ServiceInput::new(std::io::Cursor::new(
                    content.as_bytes().to_vec(),
                )))
                .await
                .unwrap();

            assert_eq!(content.as_bytes(), &response[..]);
        }
    }

    #[tokio::test]
    async fn test_peek_router_read_tls_no_sni_eof() {
        async fn tls_service_fn(
            InputWithClientHello {
                mut input,
                client_hello,
            }: InputWithClientHello<impl Io + Unpin>,
        ) -> Result<&'static str, BoxError> {
            let mut v = Vec::default();
            _ = input.read_to_end(&mut v).await?;
            assert_eq!(TLS_BUT_NO_SNI, v);
            assert!(client_hello.ext_server_name().is_none());
            Ok("ok")
        }
        let tls_service = service_fn(tls_service_fn);

        let peek_tls_svc =
            PeekTlsClientHelloService::new(tls_service).with_fallback(RejectService::<
                &'static str,
                RejectError,
            >::new(
                RejectError::default()
            ));

        let response = peek_tls_svc
            .serve(ServiceInput::new(std::io::Cursor::new(
                TLS_BUT_NO_SNI.to_vec(),
            )))
            .await
            .unwrap();
        assert_eq!("ok", response);
    }
}