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
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
// Copyright 2018 Parity Technologies (UK) Ltd.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

//! Transports with timeouts on the connection setup.
//!
//! The connection setup includes all protocol upgrades applied on the
//! underlying `Transport`.
// TODO: add example

use crate::{Multiaddr, Transport, transport::{TransportError, ListenerEvent}};
use futures::prelude::*;
use futures_timer::Delay;
use std::{error, fmt, io, pin::Pin, task::Context, task::Poll, time::Duration};

/// A `TransportTimeout` is a `Transport` that wraps another `Transport` and adds
/// timeouts to all inbound and outbound connection attempts.
///
/// **Note**: `listen_on` is never subject to a timeout, only the setup of each
/// individual accepted connection.
#[derive(Debug, Copy, Clone)]
pub struct TransportTimeout<InnerTrans> {
    inner: InnerTrans,
    outgoing_timeout: Duration,
    incoming_timeout: Duration,
}

impl<InnerTrans> TransportTimeout<InnerTrans> {
    /// Wraps around a `Transport` to add timeouts to all the sockets created by it.
    pub fn new(trans: InnerTrans, timeout: Duration) -> Self {
        TransportTimeout {
            inner: trans,
            outgoing_timeout: timeout,
            incoming_timeout: timeout,
        }
    }

    /// Wraps around a `Transport` to add timeouts to the outgoing connections.
    pub fn with_outgoing_timeout(trans: InnerTrans, timeout: Duration) -> Self {
        TransportTimeout {
            inner: trans,
            outgoing_timeout: timeout,
            incoming_timeout: Duration::from_secs(100 * 365 * 24 * 3600), // 100 years
        }
    }

    /// Wraps around a `Transport` to add timeouts to the ingoing connections.
    pub fn with_ingoing_timeout(trans: InnerTrans, timeout: Duration) -> Self {
        TransportTimeout {
            inner: trans,
            outgoing_timeout: Duration::from_secs(100 * 365 * 24 * 3600), // 100 years
            incoming_timeout: timeout,
        }
    }
}

impl<InnerTrans> Transport for TransportTimeout<InnerTrans>
where
    InnerTrans: Transport,
    InnerTrans::Error: 'static,
{
    type Output = InnerTrans::Output;
    type Error = TransportTimeoutError<InnerTrans::Error>;
    type Listener = TimeoutListener<InnerTrans::Listener>;
    type ListenerUpgrade = Timeout<InnerTrans::ListenerUpgrade>;
    type Dial = Timeout<InnerTrans::Dial>;

    fn listen_on(self, addr: Multiaddr) -> Result<Self::Listener, TransportError<Self::Error>> {
        let listener = self.inner.listen_on(addr)
            .map_err(|err| err.map(TransportTimeoutError::Other))?;

        let listener = TimeoutListener {
            inner: listener,
            timeout: self.incoming_timeout,
        };

        Ok(listener)
    }

    fn dial(self, addr: Multiaddr) -> Result<Self::Dial, TransportError<Self::Error>> {
        let dial = self.inner.dial(addr)
            .map_err(|err| err.map(TransportTimeoutError::Other))?;
        Ok(Timeout {
            inner: dial,
            timer: Delay::new(self.outgoing_timeout),
        })
    }

    fn address_translation(&self, server: &Multiaddr, observed: &Multiaddr) -> Option<Multiaddr> {
        self.inner.address_translation(server, observed)
    }
}

// TODO: can be removed and replaced with an `impl Stream` once impl Trait is fully stable
//       in Rust (https://github.com/rust-lang/rust/issues/34511)
#[pin_project::pin_project]
pub struct TimeoutListener<InnerStream> {
    #[pin]
    inner: InnerStream,
    timeout: Duration,
}

impl<InnerStream, O, E> Stream for TimeoutListener<InnerStream>
where
    InnerStream: TryStream<Ok = ListenerEvent<O, E>, Error = E>,
{
    type Item = Result<ListenerEvent<Timeout<O>, TransportTimeoutError<E>>, TransportTimeoutError<E>>;

    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
        let this = self.project();

        let poll_out = match TryStream::try_poll_next(this.inner, cx) {
            Poll::Ready(Some(Err(err))) => return Poll::Ready(Some(Err(TransportTimeoutError::Other(err)))),
            Poll::Ready(Some(Ok(v))) => v,
            Poll::Ready(None) => return Poll::Ready(None),
            Poll::Pending => return Poll::Pending,
        };

        let timeout = *this.timeout;
        let event = poll_out
            .map(move |inner_fut| {
                Timeout {
                    inner: inner_fut,
                    timer: Delay::new(timeout),
                }
            })
            .map_err(TransportTimeoutError::Other);

        Poll::Ready(Some(Ok(event)))
    }
}

/// Wraps around a `Future`. Turns the error type from `TimeoutError<Err>` to
/// `TransportTimeoutError<Err>`.
// TODO: can be replaced with `impl Future` once `impl Trait` are fully stable in Rust
//       (https://github.com/rust-lang/rust/issues/34511)
#[pin_project::pin_project]
#[must_use = "futures do nothing unless polled"]
pub struct Timeout<InnerFut> {
    #[pin]
    inner: InnerFut,
    timer: Delay,
}

impl<InnerFut> Future for Timeout<InnerFut>
where
    InnerFut: TryFuture,
{
    type Output = Result<InnerFut::Ok, TransportTimeoutError<InnerFut::Error>>;

    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
        // It is debatable whether we should poll the inner future first or the timer first.
        // For example, if you start dialing with a timeout of 10 seconds, then after 15 seconds
        // the dialing succeeds on the wire, then after 20 seconds you poll, then depending on
        // which gets polled first, the outcome will be success or failure.

        let mut this = self.project();

        match TryFuture::try_poll(this.inner, cx) {
            Poll::Pending => {},
            Poll::Ready(Ok(v)) => return Poll::Ready(Ok(v)),
            Poll::Ready(Err(err)) => return Poll::Ready(Err(TransportTimeoutError::Other(err))),
        }

        match Pin::new(&mut this.timer).poll(cx) {
            Poll::Pending => Poll::Pending,
            Poll::Ready(()) => Poll::Ready(Err(TransportTimeoutError::Timeout))
        }
    }
}

/// Error that can be produced by the `TransportTimeout` layer.
#[derive(Debug)]
pub enum TransportTimeoutError<TErr> {
    /// The transport timed out.
    Timeout,
    /// An error happened in the timer.
    TimerError(io::Error),
    /// Other kind of error.
    Other(TErr),
}

impl<TErr> fmt::Display for TransportTimeoutError<TErr>
where TErr: fmt::Display,
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            TransportTimeoutError::Timeout => write!(f, "Timeout has been reached"),
            TransportTimeoutError::TimerError(err) => write!(f, "Error in the timer: {}", err),
            TransportTimeoutError::Other(err) => write!(f, "{}", err),
        }
    }
}

impl<TErr> error::Error for TransportTimeoutError<TErr>
where TErr: error::Error + 'static,
{
    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
        match self {
            TransportTimeoutError::Timeout => None,
            TransportTimeoutError::TimerError(err) => Some(err),
            TransportTimeoutError::Other(err) => Some(err),
        }
    }
}