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
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300

use std::error::Error as StdError;
#[cfg(feature = "runtime")]
use std::time::Duration;

use futures_channel::{mpsc, oneshot};
use futures_util::future::{self, Either, FutureExt as _, TryFutureExt as _};
use futures_util::stream::StreamExt as _;
use h2::client::{Builder, SendRequest};
use tokio::io::{AsyncRead, AsyncWrite};

use super::{decode_content_length, ping, PipeToSendStream, SendBuf};
use crate::body::HttpBody;
use crate::common::{task, exec::Exec, Future, Never, Pin, Poll};
use crate::headers;
use crate::proto::Dispatched;
use crate::{Body, Request, Response};

type ClientRx<B> = crate::client::dispatch::Receiver<Request<B>, Response<Body>>;

///// An mpsc channel is used to help notify the `Connection` task when *all*
///// other handles to it have been dropped, so that it can shutdown.
type ConnDropRef = mpsc::Sender<Never>;

///// A oneshot channel watches the `Connection` task, and when it completes,
///// the "dispatch" task will be notified and can shutdown sooner.
type ConnEof = oneshot::Receiver<Never>;

// Our defaults are chosen for the "majority" case, which usually are not
// resource constrained, and so the spec default of 64kb can be too limiting
// for performance.
const DEFAULT_CONN_WINDOW: u32 = 1024 * 1024 * 5; // 5mb
const DEFAULT_STREAM_WINDOW: u32 = 1024 * 1024 * 2; // 2mb
const DEFAULT_MAX_FRAME_SIZE: u32 = 1024 * 16; // 16kb

#[derive(Clone, Debug)]
pub(crate) struct Config {
    pub(crate) adaptive_window: bool,
    pub(crate) initial_conn_window_size: u32,
    pub(crate) initial_stream_window_size: u32,
    pub(crate) max_frame_size: u32,
    #[cfg(feature = "runtime")]
    pub(crate) keep_alive_interval: Option<Duration>,
    #[cfg(feature = "runtime")]
    pub(crate) keep_alive_timeout: Duration,
    #[cfg(feature = "runtime")]
    pub(crate) keep_alive_while_idle: bool,
}

impl Default for Config {
    fn default() -> Config {
        Config {
            adaptive_window: false,
            initial_conn_window_size: DEFAULT_CONN_WINDOW,
            initial_stream_window_size: DEFAULT_STREAM_WINDOW,
            max_frame_size: DEFAULT_MAX_FRAME_SIZE,
            #[cfg(feature = "runtime")]
            keep_alive_interval: None,
            #[cfg(feature = "runtime")]
            keep_alive_timeout: Duration::from_secs(20),
            #[cfg(feature = "runtime")]
            keep_alive_while_idle: false,
        }
    }
}

pub(crate) async fn handshake<T, B>(
    io: T,
    req_rx: ClientRx<B>,
    config: &Config,
    exec: Exec,
) -> crate::Result<ClientTask<B>>
where
    T: AsyncRead + AsyncWrite + Send + Unpin + 'static,
    B: HttpBody,
    B::Data: Send + 'static,
{
    let (h2_tx, mut conn) = Builder::default()
        .initial_window_size(config.initial_stream_window_size)
        .initial_connection_window_size(config.initial_conn_window_size)
        .max_frame_size(config.max_frame_size)
        .enable_push(false)
        .handshake::<_, SendBuf<B::Data>>(io)
        .await
        .map_err(crate::Error::new_h2)?;

    // An mpsc channel is used entirely to detect when the
    // 'Client' has been dropped. This is to get around a bug
    // in h2 where dropping all SendRequests won't notify a
    // parked Connection.
    let (conn_drop_ref, rx) = mpsc::channel(1);
    let (cancel_tx, conn_eof) = oneshot::channel();

    let conn_drop_rx = rx.into_future().map(|(item, _rx)| {
        if let Some(never) = item {
            match never {}
        }
    });

    let ping_config = ping::Config {
        bdp_initial_window: if config.adaptive_window {
            Some(config.initial_stream_window_size)
        } else {
            None
        },
        #[cfg(feature = "runtime")]
        keep_alive_interval: config.keep_alive_interval,
        #[cfg(feature = "runtime")]
        keep_alive_timeout: config.keep_alive_timeout,
        #[cfg(feature = "runtime")]
        keep_alive_while_idle: config.keep_alive_while_idle,
    };

    let ping = if ping_config.is_enabled() {
        let pp = conn.ping_pong().expect("conn.ping_pong");
        let (recorder, mut ponger) = ping::channel(pp, ping_config);

        let conn = future::poll_fn(move |cx| {
            match ponger.poll(cx) {
                Poll::Ready(ping::Ponged::SizeUpdate(wnd)) => {
                    conn.set_target_window_size(wnd);
                    conn.set_initial_window_size(wnd)?;
                }
                #[cfg(feature = "runtime")]
                Poll::Ready(ping::Ponged::KeepAliveTimedOut) => {
                    debug!("connection keep-alive timed out");
                    return Poll::Ready(Ok(()));
                }
                Poll::Pending => {}
            }

            Pin::new(&mut conn).poll(cx)
        });
        let conn = conn.map_err(|e| debug!("connection error: {}", e));

        exec.execute(conn_task(conn, conn_drop_rx, cancel_tx));
        recorder
    } else {
        let conn = conn.map_err(|e| debug!("connection error: {}", e));

        exec.execute(conn_task(conn, conn_drop_rx, cancel_tx));
        ping::disabled()
    };

    Ok(ClientTask {
        ping,
        conn_drop_ref,
        conn_eof,
        executor: exec,
        h2_tx,
        req_rx,
    })
}

async fn conn_task<C, D>(conn: C, drop_rx: D, cancel_tx: oneshot::Sender<Never>)
where
    C: Future + Unpin,
    D: Future<Output = ()> + Unpin,
{
    match future::select(conn, drop_rx).await {
        Either::Left(_) => {
            // ok or err, the `conn` has finished
        }
        Either::Right(((), conn)) => {
            // mpsc has been dropped, hopefully polling
            // the connection some more should start shutdown
            // and then close
            trace!("send_request dropped, starting conn shutdown");
            drop(cancel_tx);
            let _ = conn.await;
        }
    }
}

pub(crate) struct ClientTask<B>
where
    B: HttpBody,
{
    ping: ping::Recorder,
    conn_drop_ref: ConnDropRef,
    conn_eof: ConnEof,
    executor: Exec,
    h2_tx: SendRequest<SendBuf<B::Data>>,
    req_rx: ClientRx<B>,
}

impl<B> Future for ClientTask<B>
where
    B: HttpBody + Send + 'static,
    B::Data: Send,
    B::Error: Into<Box<dyn StdError + Send + Sync>>,
{
    type Output = crate::Result<Dispatched>;

    fn poll(mut self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<Self::Output> {
        loop {
            match ready!(self.h2_tx.poll_ready(cx)) {
                Ok(()) => (),
                Err(err) => {
                    self.ping.ensure_not_timed_out()?;
                    return if err.reason() == Some(::h2::Reason::NO_ERROR) {
                        trace!("connection gracefully shutdown");
                        Poll::Ready(Ok(Dispatched::Shutdown))
                    } else {
                        Poll::Ready(Err(crate::Error::new_h2(err)))
                    };
                }
            };

            match Pin::new(&mut self.req_rx).poll_next(cx) {
                Poll::Ready(Some((req, cb))) => {
                    // check that future hasn't been canceled already
                    if cb.is_canceled() {
                        trace!("request callback is canceled");
                        continue;
                    }
                    let (head, body) = req.into_parts();
                    let mut req = ::http::Request::from_parts(head, ());
                    super::strip_connection_headers(req.headers_mut(), true);
                    if let Some(len) = body.size_hint().exact() {
                        if len != 0 || headers::method_has_defined_payload_semantics(req.method()) {
                            headers::set_content_length_if_missing(req.headers_mut(), len);
                        }
                    }
                    let eos = body.is_end_stream();
                    let (fut, body_tx) = match self.h2_tx.send_request(req, eos) {
                        Ok(ok) => ok,
                        Err(err) => {
                            debug!("client send request error: {}", err);
                            cb.send(Err((crate::Error::new_h2(err), None)));
                            continue;
                        }
                    };

                    let ping = self.ping.clone();
                    if !eos {
                        let mut pipe = Box::pin(PipeToSendStream::new(body, body_tx)).map(|res| {
                            if let Err(e) = res {
                                debug!("client request body error: {}", e);
                            }
                        });

                        // eagerly see if the body pipe is ready and
                        // can thus skip allocating in the executor
                        match Pin::new(&mut pipe).poll(cx) {
                            Poll::Ready(_) => (),
                            Poll::Pending => {
                                let conn_drop_ref = self.conn_drop_ref.clone();
                                // keep the ping recorder's knowledge of an
                                // "open stream" alive while this body is
                                // still sending...
                                let ping = ping.clone();
                                let pipe = pipe.map(move |x| {
                                    drop(conn_drop_ref);
                                    drop(ping);
                                    x
                                });
                                self.executor.execute(pipe);
                            }
                        }
                    }

                    let fut = fut.map(move |result| match result {
                        Ok(res) => {
                            // record that we got the response headers
                            ping.record_non_data();

                            let content_length = decode_content_length(res.headers());
                            let res = res.map(|stream| {
                                let ping = ping.for_stream(&stream);
                                crate::Body::h2(stream, content_length, ping)
                            });
                            Ok(res)
                        }
                        Err(err) => {
                            ping.ensure_not_timed_out().map_err(|e| (e, None))?;

                            debug!("client response error: {}", err);
                            Err((crate::Error::new_h2(err), None))
                        }
                    });
                    self.executor.execute(cb.send_when(fut));
                    continue;
                }

                Poll::Ready(None) => {
                    trace!("client::dispatch::Sender dropped");
                    return Poll::Ready(Ok(Dispatched::Shutdown));
                }

                Poll::Pending => match ready!(Pin::new(&mut self.conn_eof).poll(cx)) {
                    Ok(never) => match never {},
                    Err(_conn_is_eof) => {
                        trace!("connection task is closed, closing dispatch task");
                        return Poll::Ready(Ok(Dispatched::Shutdown));
                    }
                },
            }
        }
    }
}