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//! Server implementation of the HTTP/2 protocol.
//!
//! # Getting started
//!
//! Running an HTTP/2 server requires the caller to manage accepting the
//! connections as well as getting the connections to a state that is ready to
//! begin the HTTP/2 handshake. See [here](../index.html#handshake) for more
//! details.
//!
//! This could be as basic as using Tokio's [`TcpListener`] to accept
//! connections, but usually it means using either ALPN or HTTP/1.1 protocol
//! upgrades.
//!
//! Once a connection is obtained, it is passed to [`handshake`],
//! which will begin the [HTTP/2 handshake]. This returns a future that
//! completes once the handshake process is performed and HTTP/2 streams may
//! be received.
//!
//! [`handshake`] uses default configuration values. There are a number of
//! settings that can be changed by using [`Builder`] instead.
//!
//! # Inbound streams
//!
//! The [`Connection`] instance is used to accept inbound HTTP/2 streams. It
//! does this by implementing [`futures::Stream`]. When a new stream is
//! received, a call to [`Connection::accept`] will return `(request, response)`.
//! The `request` handle (of type [`http::Request<RecvStream>`]) contains the
//! HTTP request head as well as provides a way to receive the inbound data
//! stream and the trailers. The `response` handle (of type [`SendResponse`])
//! allows responding to the request, stream the response payload, send
//! trailers, and send push promises.
//!
//! The send ([`SendStream`]) and receive ([`RecvStream`]) halves of the stream
//! can be operated independently.
//!
//! # Managing the connection
//!
//! The [`Connection`] instance is used to manage connection state. The caller
//! is required to call either [`Connection::accept`] or
//! [`Connection::poll_close`] in order to advance the connection state. Simply
//! operating on [`SendStream`] or [`RecvStream`] will have no effect unless the
//! connection state is advanced.
//!
//! It is not required to call **both** [`Connection::accept`] and
//! [`Connection::poll_close`]. If the caller is ready to accept a new stream,
//! then only [`Connection::accept`] should be called. When the caller **does
//! not** want to accept a new stream, [`Connection::poll_close`] should be
//! called.
//!
//! The [`Connection`] instance should only be dropped once
//! [`Connection::poll_close`] returns `Ready`. Once [`Connection::accept`]
//! returns `Ready(None)`, there will no longer be any more inbound streams. At
//! this point, only [`Connection::poll_close`] should be called.
//!
//! # Shutting down the server
//!
//! Graceful shutdown of the server is [not yet
//!
//! # Example
//!
//! A basic HTTP/2 server example that runs over TCP and assumes [prior
//! knowledge], i.e. both the client and the server assume that the TCP socket
//! will use the HTTP/2 protocol without prior negotiation.
//!
//! ```no_run
//! use h2::server;
//! use http::{Response, StatusCode};
//! use tokio::net::TcpListener;
//!
//! #[tokio::main]
//! pub async fn main() {
//! let mut listener = TcpListener::bind("127.0.0.1:5928").await.unwrap();
//!
//! // Accept all incoming TCP connections.
//! loop {
//! if let Ok((socket, _peer_addr)) = listener.accept().await {
//! // Spawn a new task to process each connection.
//! tokio::spawn(async {
//! // Start the HTTP/2 connection handshake
//! let mut h2 = server::handshake(socket).await.unwrap();
//! // Accept all inbound HTTP/2 streams sent over the
//! // connection.
//! while let Some(request) = h2.accept().await {
//! let (request, mut respond) = request.unwrap();
//! println!("Received request: {:?}", request);
//!
//! // Build a response with no body
//! let response = Response::builder()
//! .status(StatusCode::OK)
//! .body(())
//! .unwrap();
//!
//! // Send the response back to the client
//! respond.send_response(response, true)
//! .unwrap();
//! }
//!
//! });
//! }
//! }
//! }
//! ```
//!
//! [`handshake`]: fn.handshake.html
//! [`Builder`]: struct.Builder.html
//! [`Connection`]: struct.Connection.html
//! [`Connection::poll`]: struct.Connection.html#method.poll
//! [`Connection::poll_close`]: struct.Connection.html#method.poll_close
//! [`http::Request<RecvStream>`]: ../struct.RecvStream.html
//! [`RecvStream`]: ../struct.RecvStream.html
//! [`SendStream`]: ../struct.SendStream.html
use crate::codec::{Codec, UserError};
use crate::frame::{self, Pseudo, PushPromiseHeaderError, Reason, Settings, StreamId};
use crate::proto::{self, Config, Error, Prioritized};
use crate::{FlowControl, PingPong, RecvStream, SendStream};
use bytes::{Buf, Bytes};
use http::{HeaderMap, Method, Request, Response};
use std::future::Future;
use std::pin::Pin;
use std::task::{Context, Poll};
use std::time::Duration;
use std::{fmt, io};
use tokio::io::{AsyncRead, AsyncWrite, ReadBuf};
use tracing::instrument::{Instrument, Instrumented};
/// In progress HTTP/2 connection handshake future.
///
/// This type implements `Future`, yielding a `Connection` instance once the
/// handshake has completed.
///
/// The handshake is completed once the connection preface is fully received
/// from the client **and** the initial settings frame is sent to the client.
///
/// The handshake future does not wait for the initial settings frame from the
/// client.
///
/// See [module] level docs for more details.
///
/// [module]: index.html
#[must_use = "futures do nothing unless polled"]
pub struct Handshake<T, B: Buf = Bytes> {
/// The config to pass to Connection::new after handshake succeeds.
builder: Builder,
/// The current state of the handshake.
state: Handshaking<T, B>,
/// Span tracking the handshake
span: tracing::Span,
}
/// Accepts inbound HTTP/2 streams on a connection.
///
/// A `Connection` is backed by an I/O resource (usually a TCP socket) and
/// implements the HTTP/2 server logic for that connection. It is responsible
/// for receiving inbound streams initiated by the client as well as driving the
/// internal state forward.
///
/// `Connection` values are created by calling [`handshake`]. Once a
/// `Connection` value is obtained, the caller must call [`poll`] or
/// [`poll_close`] in order to drive the internal connection state forward.
///
/// See [module level] documentation for more details
///
/// [module level]: index.html
/// [`handshake`]: struct.Connection.html#method.handshake
/// [`poll`]: struct.Connection.html#method.poll
/// [`poll_close`]: struct.Connection.html#method.poll_close
///
/// # Examples
///
/// ```
/// # use tokio::io::{AsyncRead, AsyncWrite};
/// # use h2::server;
/// # use h2::server::*;
/// #
/// # async fn doc<T: AsyncRead + AsyncWrite + Unpin>(my_io: T) {
/// let mut server = server::handshake(my_io).await.unwrap();
/// while let Some(request) = server.accept().await {
/// tokio::spawn(async move {
/// let (request, respond) = request.unwrap();
/// // Process the request and send the response back to the client
/// // using `respond`.
/// });
/// }
/// # }
/// #
/// # pub fn main() {}
/// ```
#[must_use = "streams do nothing unless polled"]
pub struct Connection<T, B: Buf> {
connection: proto::Connection<T, Peer, B>,
}
/// Builds server connections with custom configuration values.
///
/// Methods can be chained in order to set the configuration values.
///
/// The server is constructed by calling [`handshake`] and passing the I/O
/// handle that will back the HTTP/2 server.
///
/// New instances of `Builder` are obtained via [`Builder::new`].
///
/// See function level documentation for details on the various server
/// configuration settings.
///
/// [`Builder::new`]: struct.Builder.html#method.new
/// [`handshake`]: struct.Builder.html#method.handshake
///
/// # Examples
///
/// ```
/// # use tokio::io::{AsyncRead, AsyncWrite};
/// # use h2::server::*;
/// #
/// # fn doc<T: AsyncRead + AsyncWrite + Unpin>(my_io: T)
/// # -> Handshake<T>
/// # {
/// // `server_fut` is a future representing the completion of the HTTP/2
/// // handshake.
/// let server_fut = Builder::new()
/// .initial_window_size(1_000_000)
/// .max_concurrent_streams(1000)
/// .handshake(my_io);
/// # server_fut
/// # }
/// #
/// # pub fn main() {}
/// ```
#[derive(Clone, Debug)]
pub struct Builder {
/// Time to keep locally reset streams around before reaping.
reset_stream_duration: Duration,
/// Maximum number of locally reset streams to keep at a time.
reset_stream_max: usize,
/// Maximum number of remotely reset streams to allow in the pending
/// accept queue.
pending_accept_reset_stream_max: usize,
/// Initial `Settings` frame to send as part of the handshake.
settings: Settings,
/// Initial target window size for new connections.
initial_target_connection_window_size: Option<u32>,
/// Maximum amount of bytes to "buffer" for writing per stream.
max_send_buffer_size: usize,
}
/// Send a response back to the client
///
/// A `SendResponse` instance is provided when receiving a request and is used
/// to send the associated response back to the client. It is also used to
/// explicitly reset the stream with a custom reason.
///
/// It will also be used to initiate push promises linked with the associated
/// stream.
///
/// If the `SendResponse` instance is dropped without sending a response, then
/// the HTTP/2 stream will be reset.
///
/// See [module] level docs for more details.
///
/// [module]: index.html
#[derive(Debug)]
pub struct SendResponse<B: Buf> {
inner: proto::StreamRef<B>,
}
/// Send a response to a promised request
///
/// A `SendPushedResponse` instance is provided when promising a request and is used
/// to send the associated response to the client. It is also used to
/// explicitly reset the stream with a custom reason.
///
/// It can not be used to initiate push promises.
///
/// If the `SendPushedResponse` instance is dropped without sending a response, then
/// the HTTP/2 stream will be reset.
///
/// See [module] level docs for more details.
///
/// [module]: index.html
pub struct SendPushedResponse<B: Buf> {
inner: SendResponse<B>,
}
// Manual implementation necessary because of rust-lang/rust#26925
impl<B: Buf + fmt::Debug> fmt::Debug for SendPushedResponse<B> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "SendPushedResponse {{ {:?} }}", self.inner)
}
}
/// Stages of an in-progress handshake.
enum Handshaking<T, B: Buf> {
/// State 1. Connection is flushing pending SETTINGS frame.
Flushing(Instrumented<Flush<T, Prioritized<B>>>),
/// State 2. Connection is waiting for the client preface.
ReadingPreface(Instrumented<ReadPreface<T, Prioritized<B>>>),
/// State 3. Handshake is done, polling again would panic.
Done,
}
/// Flush a Sink
struct Flush<T, B> {
codec: Option<Codec<T, B>>,
}
/// Read the client connection preface
struct ReadPreface<T, B> {
codec: Option<Codec<T, B>>,
pos: usize,
}
#[derive(Debug)]
pub(crate) struct Peer;
const PREFACE: [u8; 24] = *b"PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n";
/// Creates a new configured HTTP/2 server with default configuration
/// values backed by `io`.
///
/// It is expected that `io` already be in an appropriate state to commence
/// the [HTTP/2 handshake]. See [Handshake] for more details.
///
/// Returns a future which resolves to the [`Connection`] instance once the
/// HTTP/2 handshake has been completed. The returned [`Connection`]
/// instance will be using default configuration values. Use [`Builder`] to
/// customize the configuration values used by a [`Connection`] instance.
///
/// [Handshake]: ../index.html#handshake
/// [`Connection`]: struct.Connection.html
///
/// # Examples
///
/// ```
/// # use tokio::io::{AsyncRead, AsyncWrite};
/// # use h2::server;
/// # use h2::server::*;
/// #
/// # async fn doc<T: AsyncRead + AsyncWrite + Unpin>(my_io: T)
/// # {
/// let connection = server::handshake(my_io).await.unwrap();
/// // The HTTP/2 handshake has completed, now use `connection` to
/// // accept inbound HTTP/2 streams.
/// # }
/// #
/// # pub fn main() {}
/// ```
pub fn handshake<T>(io: T) -> Handshake<T, Bytes>
where
T: AsyncRead + AsyncWrite + Unpin,
{
Builder::new().handshake(io)
}
// ===== impl Connection =====
impl<T, B> Connection<T, B>
where
T: AsyncRead + AsyncWrite + Unpin,
B: Buf,
{
fn handshake2(io: T, builder: Builder) -> Handshake<T, B> {
let span = tracing::trace_span!("server_handshake");
let entered = span.enter();
// Create the codec.
let mut codec = Codec::new(io);
if let Some(max) = builder.settings.max_frame_size() {
codec.set_max_recv_frame_size(max as usize);
}
if let Some(max) = builder.settings.max_header_list_size() {
codec.set_max_recv_header_list_size(max as usize);
}
// Send initial settings frame.
codec
.buffer(builder.settings.clone().into())
.expect("invalid SETTINGS frame");
// Create the handshake future.
let state =
Handshaking::Flushing(Flush::new(codec).instrument(tracing::trace_span!("flush")));
drop(entered);
Handshake {
builder,
state,
span,
}
}
/// Accept the next incoming request on this connection.
pub async fn accept(
&mut self,
) -> Option<Result<(Request<RecvStream>, SendResponse<B>), crate::Error>> {
futures_util::future::poll_fn(move |cx| self.poll_accept(cx)).await
}
#[doc(hidden)]
pub fn poll_accept(
&mut self,
cx: &mut Context<'_>,
) -> Poll<Option<Result<(Request<RecvStream>, SendResponse<B>), crate::Error>>> {
// Always try to advance the internal state. Getting Pending also is
// needed to allow this function to return Pending.
if self.poll_closed(cx)?.is_ready() {
// If the socket is closed, don't return anything
// TODO: drop any pending streams
return Poll::Ready(None);
}
if let Some(inner) = self.connection.next_incoming() {
tracing::trace!("received incoming");
let (head, _) = inner.take_request().into_parts();
let body = RecvStream::new(FlowControl::new(inner.clone_to_opaque()));
let request = Request::from_parts(head, body);
let respond = SendResponse { inner };
return Poll::Ready(Some(Ok((request, respond))));
}
Poll::Pending
}
/// Sets the target window size for the whole connection.
///
/// If `size` is greater than the current value, then a `WINDOW_UPDATE`
/// frame will be immediately sent to the remote, increasing the connection
/// level window by `size - current_value`.
///
/// If `size` is less than the current value, nothing will happen
/// immediately. However, as window capacity is released by
/// [`FlowControl`] instances, no `WINDOW_UPDATE` frames will be sent
/// out until the number of "in flight" bytes drops below `size`.
///
/// The default value is 65,535.
///
/// See [`FlowControl`] documentation for more details.
///
/// [`FlowControl`]: ../struct.FlowControl.html
/// [library level]: ../index.html#flow-control
pub fn set_target_window_size(&mut self, size: u32) {
assert!(size <= proto::MAX_WINDOW_SIZE);
self.connection.set_target_window_size(size);
}
/// Set a new `INITIAL_WINDOW_SIZE` setting (in octets) for stream-level
/// flow control for received data.
///
/// The `SETTINGS` will be sent to the remote, and only applied once the
/// remote acknowledges the change.
///
/// This can be used to increase or decrease the window size for existing
/// streams.
///
/// # Errors
///
/// Returns an error if a previous call is still pending acknowledgement
/// from the remote endpoint.
pub fn set_initial_window_size(&mut self, size: u32) -> Result<(), crate::Error> {
assert!(size <= proto::MAX_WINDOW_SIZE);
self.connection.set_initial_window_size(size)?;
Ok(())
}
/// Enables the [extended CONNECT protocol].
///
///
/// # Errors
///
/// Returns an error if a previous call is still pending acknowledgement
/// from the remote endpoint.
pub fn enable_connect_protocol(&mut self) -> Result<(), crate::Error> {
self.connection.set_enable_connect_protocol()?;
Ok(())
}
/// Returns `Ready` when the underlying connection has closed.
///
/// If any new inbound streams are received during a call to `poll_closed`,
/// they will be queued and returned on the next call to [`poll_accept`].
///
/// This function will advance the internal connection state, driving
/// progress on all the other handles (e.g. [`RecvStream`] and [`SendStream`]).
///
/// See [here](index.html#managing-the-connection) for more details.
///
/// [`poll_accept`]: struct.Connection.html#method.poll_accept
/// [`RecvStream`]: ../struct.RecvStream.html
/// [`SendStream`]: ../struct.SendStream.html
pub fn poll_closed(&mut self, cx: &mut Context) -> Poll<Result<(), crate::Error>> {
self.connection.poll(cx).map_err(Into::into)
}
#[doc(hidden)]
#[deprecated(note = "renamed to poll_closed")]
pub fn poll_close(&mut self, cx: &mut Context) -> Poll<Result<(), crate::Error>> {
self.poll_closed(cx)
}
/// Sets the connection to a GOAWAY state.
///
/// Does not terminate the connection. Must continue being polled to close
/// connection.
///
/// After flushing the GOAWAY frame, the connection is closed. Any
/// outstanding streams do not prevent the connection from closing. This
/// should usually be reserved for shutting down when something bad
/// external to `h2` has happened, and open streams cannot be properly
/// handled.
///
/// For graceful shutdowns, see [`graceful_shutdown`](Connection::graceful_shutdown).
pub fn abrupt_shutdown(&mut self, reason: Reason) {
self.connection.go_away_from_user(reason);
}
/// Starts a [graceful shutdown][1] process.
///
/// Must continue being polled to close connection.
///
/// It's possible to receive more requests after calling this method, since
/// they might have been in-flight from the client already. After about
/// 1 RTT, no new requests should be accepted. Once all active streams
/// have completed, the connection is closed.
///
pub fn graceful_shutdown(&mut self) {
self.connection.go_away_gracefully();
}
/// Takes a `PingPong` instance from the connection.
///
/// # Note
///
/// This may only be called once. Calling multiple times will return `None`.
pub fn ping_pong(&mut self) -> Option<PingPong> {
self.connection.take_user_pings().map(PingPong::new)
}
/// Returns the maximum number of concurrent streams that may be initiated
/// by the server on this connection.
///
/// This limit is configured by the client peer by sending the
/// [`SETTINGS_MAX_CONCURRENT_STREAMS` parameter][1] in a `SETTINGS` frame.
/// This method returns the currently acknowledged value received from the
/// remote.
///
pub fn max_concurrent_send_streams(&self) -> usize {
self.connection.max_send_streams()
}
/// Returns the maximum number of concurrent streams that may be initiated
/// by the client on this connection.
///
/// This returns the value of the [`SETTINGS_MAX_CONCURRENT_STREAMS`
/// parameter][1] sent in a `SETTINGS` frame that has been
/// acknowledged by the remote peer. The value to be sent is configured by
/// the [`Builder::max_concurrent_streams`][2] method before handshaking
/// with the remote peer.
///
/// [2]: ../struct.Builder.html#method.max_concurrent_streams
pub fn max_concurrent_recv_streams(&self) -> usize {
self.connection.max_recv_streams()
}
// Could disappear at anytime.
#[doc(hidden)]
#[cfg(feature = "unstable")]
pub fn num_wired_streams(&self) -> usize {
self.connection.num_wired_streams()
}
}
#[cfg(feature = "stream")]
impl<T, B> futures_core::Stream for Connection<T, B>
where
T: AsyncRead + AsyncWrite + Unpin,
B: Buf,
{
type Item = Result<(Request<RecvStream>, SendResponse<B>), crate::Error>;
fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
self.poll_accept(cx)
}
}
impl<T, B> fmt::Debug for Connection<T, B>
where
T: fmt::Debug,
B: fmt::Debug + Buf,
{
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
fmt.debug_struct("Connection")
.field("connection", &self.connection)
.finish()
}
}
// ===== impl Builder =====
impl Builder {
/// Returns a new server builder instance initialized with default
/// configuration values.
///
/// Configuration methods can be chained on the return value.
///
/// # Examples
///
/// ```
/// # use tokio::io::{AsyncRead, AsyncWrite};
/// # use h2::server::*;
/// #
/// # fn doc<T: AsyncRead + AsyncWrite + Unpin>(my_io: T)
/// # -> Handshake<T>
/// # {
/// // `server_fut` is a future representing the completion of the HTTP/2
/// // handshake.
/// let server_fut = Builder::new()
/// .initial_window_size(1_000_000)
/// .max_concurrent_streams(1000)
/// .handshake(my_io);
/// # server_fut
/// # }
/// #
/// # pub fn main() {}
/// ```
pub fn new() -> Builder {
Builder {
reset_stream_duration: Duration::from_secs(proto::DEFAULT_RESET_STREAM_SECS),
reset_stream_max: proto::DEFAULT_RESET_STREAM_MAX,
pending_accept_reset_stream_max: proto::DEFAULT_REMOTE_RESET_STREAM_MAX,
settings: Settings::default(),
initial_target_connection_window_size: None,
max_send_buffer_size: proto::DEFAULT_MAX_SEND_BUFFER_SIZE,
}
}
/// Indicates the initial window size (in octets) for stream-level
/// flow control for received data.
///
/// The initial window of a stream is used as part of flow control. For more
/// details, see [`FlowControl`].
///
/// The default value is 65,535.
///
/// [`FlowControl`]: ../struct.FlowControl.html
///
/// # Examples
///
/// ```
/// # use tokio::io::{AsyncRead, AsyncWrite};
/// # use h2::server::*;
/// #
/// # fn doc<T: AsyncRead + AsyncWrite + Unpin>(my_io: T)
/// # -> Handshake<T>
/// # {
/// // `server_fut` is a future representing the completion of the HTTP/2
/// // handshake.
/// let server_fut = Builder::new()
/// .initial_window_size(1_000_000)
/// .handshake(my_io);
/// # server_fut
/// # }
/// #
/// # pub fn main() {}
/// ```
pub fn initial_window_size(&mut self, size: u32) -> &mut Self {
self.settings.set_initial_window_size(Some(size));
self
}
/// Indicates the initial window size (in octets) for connection-level flow control
/// for received data.
///
/// The initial window of a connection is used as part of flow control. For more details,
/// see [`FlowControl`].
///
/// The default value is 65,535.
///
/// [`FlowControl`]: ../struct.FlowControl.html
///
/// # Examples
///
/// ```
/// # use tokio::io::{AsyncRead, AsyncWrite};
/// # use h2::server::*;
/// #
/// # fn doc<T: AsyncRead + AsyncWrite + Unpin>(my_io: T)
/// # -> Handshake<T>
/// # {
/// // `server_fut` is a future representing the completion of the HTTP/2
/// // handshake.
/// let server_fut = Builder::new()
/// .initial_connection_window_size(1_000_000)
/// .handshake(my_io);
/// # server_fut
/// # }
/// #
/// # pub fn main() {}
/// ```
pub fn initial_connection_window_size(&mut self, size: u32) -> &mut Self {
self.initial_target_connection_window_size = Some(size);
self
}
/// Indicates the size (in octets) of the largest HTTP/2 frame payload that the
/// configured server is able to accept.
///
/// The sender may send data frames that are **smaller** than this value,
/// but any data larger than `max` will be broken up into multiple `DATA`
/// frames.
///
/// The value **must** be between 16,384 and 16,777,215. The default value is 16,384.
///
/// # Examples
///
/// ```
/// # use tokio::io::{AsyncRead, AsyncWrite};
/// # use h2::server::*;
/// #
/// # fn doc<T: AsyncRead + AsyncWrite + Unpin>(my_io: T)
/// # -> Handshake<T>
/// # {
/// // `server_fut` is a future representing the completion of the HTTP/2
/// // handshake.
/// let server_fut = Builder::new()
/// .max_frame_size(1_000_000)
/// .handshake(my_io);
/// # server_fut
/// # }
/// #
/// # pub fn main() {}
/// ```
///
/// # Panics
///
/// This function panics if `max` is not within the legal range specified
/// above.
pub fn max_frame_size(&mut self, max: u32) -> &mut Self {
self.settings.set_max_frame_size(Some(max));
self
}
/// Sets the max size of received header frames.
///
/// This advisory setting informs a peer of the maximum size of header list
/// that the sender is prepared to accept, in octets. The value is based on
/// the uncompressed size of header fields, including the length of the name
/// and value in octets plus an overhead of 32 octets for each header field.
///
/// This setting is also used to limit the maximum amount of data that is
/// buffered to decode HEADERS frames.
///
/// # Examples
///
/// ```
/// # use tokio::io::{AsyncRead, AsyncWrite};
/// # use h2::server::*;
/// #
/// # fn doc<T: AsyncRead + AsyncWrite + Unpin>(my_io: T)
/// # -> Handshake<T>
/// # {
/// // `server_fut` is a future representing the completion of the HTTP/2
/// // handshake.
/// let server_fut = Builder::new()
/// .max_header_list_size(16 * 1024)
/// .handshake(my_io);
/// # server_fut
/// # }
/// #
/// # pub fn main() {}
/// ```
pub fn max_header_list_size(&mut self, max: u32) -> &mut Self {
self.settings.set_max_header_list_size(Some(max));
self
}
/// Sets the maximum number of concurrent streams.
///
/// The maximum concurrent streams setting only controls the maximum number
/// of streams that can be initiated by the remote peer. In other words,
/// when this setting is set to 100, this does not limit the number of
/// concurrent streams that can be created by the caller.
///
/// It is recommended that this value be no smaller than 100, so as to not
/// unnecessarily limit parallelism. However, any value is legal, including
/// 0. If `max` is set to 0, then the remote will not be permitted to
/// initiate streams.
///
/// Note that streams in the reserved state, i.e., push promises that have
/// been reserved but the stream has not started, do not count against this
/// setting.
///
/// Also note that if the remote *does* exceed the value set here, it is not
/// a protocol level error. Instead, the `h2` library will immediately reset
/// the stream.
///
/// See [Section 5.1.2] in the HTTP/2 spec for more details.
///
///
/// # Examples
///
/// ```
/// # use tokio::io::{AsyncRead, AsyncWrite};
/// # use h2::server::*;
/// #
/// # fn doc<T: AsyncRead + AsyncWrite + Unpin>(my_io: T)
/// # -> Handshake<T>
/// # {
/// // `server_fut` is a future representing the completion of the HTTP/2
/// // handshake.
/// let server_fut = Builder::new()
/// .max_concurrent_streams(1000)
/// .handshake(my_io);
/// # server_fut
/// # }
/// #
/// # pub fn main() {}
/// ```
pub fn max_concurrent_streams(&mut self, max: u32) -> &mut Self {
self.settings.set_max_concurrent_streams(Some(max));
self
}
/// Sets the maximum number of concurrent locally reset streams.
///
/// When a stream is explicitly reset by either calling
/// [`SendResponse::send_reset`] or by dropping a [`SendResponse`] instance
/// before completing the stream, the HTTP/2 specification requires that
/// any further frames received for that stream must be ignored for "some
/// time".
///
/// In order to satisfy the specification, internal state must be maintained
/// to implement the behavior. This state grows linearly with the number of
/// streams that are locally reset.
///
/// The `max_concurrent_reset_streams` setting configures sets an upper
/// bound on the amount of state that is maintained. When this max value is
/// reached, the oldest reset stream is purged from memory.
///
/// Once the stream has been fully purged from memory, any additional frames
/// received for that stream will result in a connection level protocol
/// error, forcing the connection to terminate.
///
/// The default value is 10.
///
/// # Examples
///
/// ```
/// # use tokio::io::{AsyncRead, AsyncWrite};
/// # use h2::server::*;
/// #
/// # fn doc<T: AsyncRead + AsyncWrite + Unpin>(my_io: T)
/// # -> Handshake<T>
/// # {
/// // `server_fut` is a future representing the completion of the HTTP/2
/// // handshake.
/// let server_fut = Builder::new()
/// .max_concurrent_reset_streams(1000)
/// .handshake(my_io);
/// # server_fut
/// # }
/// #
/// # pub fn main() {}
/// ```
pub fn max_concurrent_reset_streams(&mut self, max: usize) -> &mut Self {
self.reset_stream_max = max;
self
}
/// Sets the maximum number of pending-accept remotely-reset streams.
///
/// Streams that have been received by the peer, but not accepted by the
/// user, can also receive a RST_STREAM. This is a legitimate pattern: one
/// could send a request and then shortly after, realize it is not needed,
/// sending a CANCEL.
///
/// However, since those streams are now "closed", they don't count towards
/// the max concurrent streams. So, they will sit in the accept queue,
/// using memory.
///
/// When the number of remotely-reset streams sitting in the pending-accept
/// queue reaches this maximum value, a connection error with the code of
/// `ENHANCE_YOUR_CALM` will be sent to the peer, and returned by the
/// `Future`.
///
/// The default value is currently 20, but could change.
///
/// # Examples
///
///
/// ```
/// # use tokio::io::{AsyncRead, AsyncWrite};
/// # use h2::server::*;
/// #
/// # fn doc<T: AsyncRead + AsyncWrite + Unpin>(my_io: T)
/// # -> Handshake<T>
/// # {
/// // `server_fut` is a future representing the completion of the HTTP/2
/// // handshake.
/// let server_fut = Builder::new()
/// .max_pending_accept_reset_streams(100)
/// .handshake(my_io);
/// # server_fut
/// # }
/// #
/// # pub fn main() {}
/// ```
pub fn max_pending_accept_reset_streams(&mut self, max: usize) -> &mut Self {
self.pending_accept_reset_stream_max = max;
self
}
/// Sets the maximum send buffer size per stream.
///
/// Once a stream has buffered up to (or over) the maximum, the stream's
/// flow control will not "poll" additional capacity. Once bytes for the
/// stream have been written to the connection, the send buffer capacity
/// will be freed up again.
///
/// The default is currently ~400KB, but may change.
///
/// # Panics
///
/// This function panics if `max` is larger than `u32::MAX`.
pub fn max_send_buffer_size(&mut self, max: usize) -> &mut Self {
assert!(max <= std::u32::MAX as usize);
self.max_send_buffer_size = max;
self
}
/// Sets the maximum number of concurrent locally reset streams.
///
/// When a stream is explicitly reset by either calling
/// [`SendResponse::send_reset`] or by dropping a [`SendResponse`] instance
/// before completing the stream, the HTTP/2 specification requires that
/// any further frames received for that stream must be ignored for "some
/// time".
///
/// In order to satisfy the specification, internal state must be maintained
/// to implement the behavior. This state grows linearly with the number of
/// streams that are locally reset.
///
/// The `reset_stream_duration` setting configures the max amount of time
/// this state will be maintained in memory. Once the duration elapses, the
/// stream state is purged from memory.
///
/// Once the stream has been fully purged from memory, any additional frames
/// received for that stream will result in a connection level protocol
/// error, forcing the connection to terminate.
///
/// The default value is 30 seconds.
///
/// # Examples
///
/// ```
/// # use tokio::io::{AsyncRead, AsyncWrite};
/// # use h2::server::*;
/// # use std::time::Duration;
/// #
/// # fn doc<T: AsyncRead + AsyncWrite + Unpin>(my_io: T)
/// # -> Handshake<T>
/// # {
/// // `server_fut` is a future representing the completion of the HTTP/2
/// // handshake.
/// let server_fut = Builder::new()
/// .reset_stream_duration(Duration::from_secs(10))
/// .handshake(my_io);
/// # server_fut
/// # }
/// #
/// # pub fn main() {}
/// ```
pub fn reset_stream_duration(&mut self, dur: Duration) -> &mut Self {
self.reset_stream_duration = dur;
self
}
/// Enables the [extended CONNECT protocol].
///
pub fn enable_connect_protocol(&mut self) -> &mut Self {
self.settings.set_enable_connect_protocol(Some(1));
self
}
/// Creates a new configured HTTP/2 server backed by `io`.
///
/// It is expected that `io` already be in an appropriate state to commence
/// the [HTTP/2 handshake]. See [Handshake] for more details.
///
/// Returns a future which resolves to the [`Connection`] instance once the
/// HTTP/2 handshake has been completed.
///
/// This function also allows the caller to configure the send payload data
/// type. See [Outbound data type] for more details.
///
/// [Handshake]: ../index.html#handshake
/// [`Connection`]: struct.Connection.html
/// [Outbound data type]: ../index.html#outbound-data-type.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// # use tokio::io::{AsyncRead, AsyncWrite};
/// # use h2::server::*;
/// #
/// # fn doc<T: AsyncRead + AsyncWrite + Unpin>(my_io: T)
/// # -> Handshake<T>
/// # {
/// // `server_fut` is a future representing the completion of the HTTP/2
/// // handshake.
/// let server_fut = Builder::new()
/// .handshake(my_io);
/// # server_fut
/// # }
/// #
/// # pub fn main() {}
/// ```
///
/// Configures the send-payload data type. In this case, the outbound data
/// type will be `&'static [u8]`.
///
/// ```
/// # use tokio::io::{AsyncRead, AsyncWrite};
/// # use h2::server::*;
/// #
/// # fn doc<T: AsyncRead + AsyncWrite + Unpin>(my_io: T)
/// # -> Handshake<T, &'static [u8]>
/// # {
/// // `server_fut` is a future representing the completion of the HTTP/2
/// // handshake.
/// let server_fut: Handshake<_, &'static [u8]> = Builder::new()
/// .handshake(my_io);
/// # server_fut
/// # }
/// #
/// # pub fn main() {}
/// ```
pub fn handshake<T, B>(&self, io: T) -> Handshake<T, B>
where
T: AsyncRead + AsyncWrite + Unpin,
B: Buf,
{
Connection::handshake2(io, self.clone())
}
}
impl Default for Builder {
fn default() -> Builder {
Builder::new()
}
}
// ===== impl SendResponse =====
impl<B: Buf> SendResponse<B> {
/// Send a response to a client request.
///
/// On success, a [`SendStream`] instance is returned. This instance can be
/// used to stream the response body and send trailers.
///
/// If a body or trailers will be sent on the returned [`SendStream`]
/// instance, then `end_of_stream` must be set to `false` when calling this
/// function.
///
/// The [`SendResponse`] instance is already associated with a received
/// request. This function may only be called once per instance and only if
/// [`send_reset`] has not been previously called.
///
/// [`SendResponse`]: #
/// [`SendStream`]: ../struct.SendStream.html
/// [`send_reset`]: #method.send_reset
pub fn send_response(
&mut self,
response: Response<()>,
end_of_stream: bool,
) -> Result<SendStream<B>, crate::Error> {
self.inner
.send_response(response, end_of_stream)
.map(|_| SendStream::new(self.inner.clone()))
.map_err(Into::into)
}
/// Push a request and response to the client
///
/// On success, a [`SendResponse`] instance is returned.
///
/// [`SendResponse`]: #
pub fn push_request(
&mut self,
request: Request<()>,
) -> Result<SendPushedResponse<B>, crate::Error> {
self.inner
.send_push_promise(request)
.map(|inner| SendPushedResponse {
inner: SendResponse { inner },
})
.map_err(Into::into)
}
/// Send a stream reset to the peer.
///
/// This essentially cancels the stream, including any inbound or outbound
/// data streams.
///
/// If this function is called before [`send_response`], a call to
/// [`send_response`] will result in an error.
///
/// If this function is called while a [`SendStream`] instance is active,
/// any further use of the instance will result in an error.
///
/// This function should only be called once.
///
/// [`send_response`]: #method.send_response
/// [`SendStream`]: ../struct.SendStream.html
pub fn send_reset(&mut self, reason: Reason) {
self.inner.send_reset(reason)
}
/// Polls to be notified when the client resets this stream.
///
/// If stream is still open, this returns `Poll::Pending`, and
/// registers the task to be notified if a `RST_STREAM` is received.
///
/// If a `RST_STREAM` frame is received for this stream, calling this
/// method will yield the `Reason` for the reset.
///
/// # Error
///
/// Calling this method after having called `send_response` will return
/// a user error.
pub fn poll_reset(&mut self, cx: &mut Context) -> Poll<Result<Reason, crate::Error>> {
self.inner.poll_reset(cx, proto::PollReset::AwaitingHeaders)
}
/// Returns the stream ID of the response stream.
///
/// # Panics
///
/// If the lock on the stream store has been poisoned.
pub fn stream_id(&self) -> crate::StreamId {
crate::StreamId::from_internal(self.inner.stream_id())
}
}
// ===== impl SendPushedResponse =====
impl<B: Buf> SendPushedResponse<B> {
/// Send a response to a promised request.
///
/// On success, a [`SendStream`] instance is returned. This instance can be
/// used to stream the response body and send trailers.
///
/// If a body or trailers will be sent on the returned [`SendStream`]
/// instance, then `end_of_stream` must be set to `false` when calling this
/// function.
///
/// The [`SendPushedResponse`] instance is associated with a promised
/// request. This function may only be called once per instance and only if
/// [`send_reset`] has not been previously called.
///
/// [`SendPushedResponse`]: #
/// [`SendStream`]: ../struct.SendStream.html
/// [`send_reset`]: #method.send_reset
pub fn send_response(
&mut self,
response: Response<()>,
end_of_stream: bool,
) -> Result<SendStream<B>, crate::Error> {
self.inner.send_response(response, end_of_stream)
}
/// Send a stream reset to the peer.
///
/// This essentially cancels the stream, including any inbound or outbound
/// data streams.
///
/// If this function is called before [`send_response`], a call to
/// [`send_response`] will result in an error.
///
/// If this function is called while a [`SendStream`] instance is active,
/// any further use of the instance will result in an error.
///
/// This function should only be called once.
///
/// [`send_response`]: #method.send_response
/// [`SendStream`]: ../struct.SendStream.html
pub fn send_reset(&mut self, reason: Reason) {
self.inner.send_reset(reason)
}
/// Polls to be notified when the client resets this stream.
///
/// If stream is still open, this returns `Poll::Pending`, and
/// registers the task to be notified if a `RST_STREAM` is received.
///
/// If a `RST_STREAM` frame is received for this stream, calling this
/// method will yield the `Reason` for the reset.
///
/// # Error
///
/// Calling this method after having called `send_response` will return
/// a user error.
pub fn poll_reset(&mut self, cx: &mut Context) -> Poll<Result<Reason, crate::Error>> {
self.inner.poll_reset(cx)
}
/// Returns the stream ID of the response stream.
///
/// # Panics
///
/// If the lock on the stream store has been poisoned.
pub fn stream_id(&self) -> crate::StreamId {
self.inner.stream_id()
}
}
// ===== impl Flush =====
impl<T, B: Buf> Flush<T, B> {
fn new(codec: Codec<T, B>) -> Self {
Flush { codec: Some(codec) }
}
}
impl<T, B> Future for Flush<T, B>
where
T: AsyncWrite + Unpin,
B: Buf,
{
type Output = Result<Codec<T, B>, crate::Error>;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
// Flush the codec
ready!(self.codec.as_mut().unwrap().flush(cx)).map_err(crate::Error::from_io)?;
// Return the codec
Poll::Ready(Ok(self.codec.take().unwrap()))
}
}
impl<T, B: Buf> ReadPreface<T, B> {
fn new(codec: Codec<T, B>) -> Self {
ReadPreface {
codec: Some(codec),
pos: 0,
}
}
fn inner_mut(&mut self) -> &mut T {
self.codec.as_mut().unwrap().get_mut()
}
}
impl<T, B> Future for ReadPreface<T, B>
where
T: AsyncRead + Unpin,
B: Buf,
{
type Output = Result<Codec<T, B>, crate::Error>;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let mut buf = [0; 24];
let mut rem = PREFACE.len() - self.pos;
while rem > 0 {
let mut buf = ReadBuf::new(&mut buf[..rem]);
ready!(Pin::new(self.inner_mut()).poll_read(cx, &mut buf))
.map_err(crate::Error::from_io)?;
let n = buf.filled().len();
if n == 0 {
return Poll::Ready(Err(crate::Error::from_io(io::Error::new(
io::ErrorKind::UnexpectedEof,
"connection closed before reading preface",
))));
}
if &PREFACE[self.pos..self.pos + n] != buf.filled() {
proto_err!(conn: "read_preface: invalid preface");
// TODO: Should this just write the GO_AWAY frame directly?
return Poll::Ready(Err(Error::library_go_away(Reason::PROTOCOL_ERROR).into()));
}
self.pos += n;
rem -= n; // TODO test
}
Poll::Ready(Ok(self.codec.take().unwrap()))
}
}
// ===== impl Handshake =====
impl<T, B: Buf> Future for Handshake<T, B>
where
T: AsyncRead + AsyncWrite + Unpin,
B: Buf,
{
type Output = Result<Connection<T, B>, crate::Error>;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let span = self.span.clone(); // XXX(eliza): T_T
let _e = span.enter();
tracing::trace!(state = ?self.state);
loop {
match &mut self.state {
Handshaking::Flushing(flush) => {
// We're currently flushing a pending SETTINGS frame. Poll the
// flush future, and, if it's completed, advance our state to wait
// for the client preface.
let codec = match Pin::new(flush).poll(cx)? {
Poll::Pending => {
tracing::trace!(flush.poll = %"Pending");
return Poll::Pending;
}
Poll::Ready(flushed) => {
tracing::trace!(flush.poll = %"Ready");
flushed
}
};
self.state = Handshaking::ReadingPreface(
ReadPreface::new(codec).instrument(tracing::trace_span!("read_preface")),
);
}
Handshaking::ReadingPreface(read) => {
let codec = ready!(Pin::new(read).poll(cx)?);
self.state = Handshaking::Done;
let connection = proto::Connection::new(
codec,
Config {
next_stream_id: 2.into(),
// Server does not need to locally initiate any streams
initial_max_send_streams: 0,
max_send_buffer_size: self.builder.max_send_buffer_size,
reset_stream_duration: self.builder.reset_stream_duration,
reset_stream_max: self.builder.reset_stream_max,
remote_reset_stream_max: self.builder.pending_accept_reset_stream_max,
settings: self.builder.settings.clone(),
},
);
tracing::trace!("connection established!");
let mut c = Connection { connection };
if let Some(sz) = self.builder.initial_target_connection_window_size {
c.set_target_window_size(sz);
}
return Poll::Ready(Ok(c));
}
Handshaking::Done => {
panic!("Handshaking::poll() called again after handshaking was complete")
}
}
}
}
}
impl<T, B> fmt::Debug for Handshake<T, B>
where
T: AsyncRead + AsyncWrite + fmt::Debug,
B: fmt::Debug + Buf,
{
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
write!(fmt, "server::Handshake")
}
}
impl Peer {
pub fn convert_send_message(
id: StreamId,
response: Response<()>,
end_of_stream: bool,
) -> frame::Headers {
use http::response::Parts;
// Extract the components of the HTTP request
let (
Parts {
status, headers, ..
},
_,
) = response.into_parts();
// Build the set pseudo header set. All requests will include `method`
// and `path`.
let pseudo = Pseudo::response(status);
// Create the HEADERS frame
let mut frame = frame::Headers::new(id, pseudo, headers);
if end_of_stream {
frame.set_end_stream()
}
frame
}
pub fn convert_push_message(
stream_id: StreamId,
promised_id: StreamId,
request: Request<()>,
) -> Result<frame::PushPromise, UserError> {
use http::request::Parts;
if let Err(e) = frame::PushPromise::validate_request(&request) {
use PushPromiseHeaderError::*;
match e {
NotSafeAndCacheable => tracing::debug!(
?promised_id,
"convert_push_message: method {} is not safe and cacheable",
request.method(),
),
InvalidContentLength(e) => tracing::debug!(
?promised_id,
"convert_push_message; promised request has invalid content-length {:?}",
e,
),
}
return Err(UserError::MalformedHeaders);
}
// Extract the components of the HTTP request
let (
Parts {
method,
uri,
headers,
..
},
_,
) = request.into_parts();
let pseudo = Pseudo::request(method, uri, None);
Ok(frame::PushPromise::new(
stream_id,
promised_id,
pseudo,
headers,
))
}
}
impl proto::Peer for Peer {
type Poll = Request<()>;
const NAME: &'static str = "Server";
fn is_server() -> bool {
true
}
fn r#dyn() -> proto::DynPeer {
proto::DynPeer::Server
}
fn convert_poll_message(
pseudo: Pseudo,
fields: HeaderMap,
stream_id: StreamId,
) -> Result<Self::Poll, Error> {
use http::{uri, Version};
let mut b = Request::builder();
macro_rules! malformed {
($($arg:tt)*) => {{
tracing::debug!($($arg)*);
return Err(Error::library_reset(stream_id, Reason::PROTOCOL_ERROR));
}}
}
b = b.version(Version::HTTP_2);
let is_connect;
if let Some(method) = pseudo.method {
is_connect = method == Method::CONNECT;
b = b.method(method);
} else {
malformed!("malformed headers: missing method");
}
let has_protocol = pseudo.protocol.is_some();
if has_protocol {
if is_connect {
// Assert that we have the right type.
b = b.extension::<crate::ext::Protocol>(pseudo.protocol.unwrap());
} else {
malformed!("malformed headers: :protocol on non-CONNECT request");
}
}
if pseudo.status.is_some() {
malformed!("malformed headers: :status field on request");
}
// Convert the URI
let mut parts = uri::Parts::default();
// A request translated from HTTP/1 must not include the :authority
// header
if let Some(authority) = pseudo.authority {
let maybe_authority = uri::Authority::from_maybe_shared(authority.clone().into_inner());
parts.authority = Some(maybe_authority.or_else(|why| {
malformed!(
"malformed headers: malformed authority ({:?}): {}",
authority,
why,
)
})?);
}
// A :scheme is required, except CONNECT.
if let Some(scheme) = pseudo.scheme {
if is_connect && !has_protocol {
malformed!("malformed headers: :scheme in CONNECT");
}
let maybe_scheme = scheme.parse();
let scheme = maybe_scheme.or_else(|why| {
malformed!(
"malformed headers: malformed scheme ({:?}): {}",
scheme,
why,
)
})?;
// It's not possible to build an `Uri` from a scheme and path. So,
// after validating is was a valid scheme, we just have to drop it
// if there isn't an :authority.
if parts.authority.is_some() {
parts.scheme = Some(scheme);
}
} else if !is_connect || has_protocol {
malformed!("malformed headers: missing scheme");
}
if let Some(path) = pseudo.path {
if is_connect && !has_protocol {
malformed!("malformed headers: :path in CONNECT");
}
// This cannot be empty
if path.is_empty() {
malformed!("malformed headers: missing path");
}
let maybe_path = uri::PathAndQuery::from_maybe_shared(path.clone().into_inner());
parts.path_and_query = Some(maybe_path.or_else(|why| {
malformed!("malformed headers: malformed path ({:?}): {}", path, why,)
})?);
} else if is_connect && has_protocol {
malformed!("malformed headers: missing path in extended CONNECT");
}
b = b.uri(parts);
let mut request = match b.body(()) {
Ok(request) => request,
Err(e) => {
// TODO: Should there be more specialized handling for different
// kinds of errors
proto_err!(stream: "error building request: {}; stream={:?}", e, stream_id);
return Err(Error::library_reset(stream_id, Reason::PROTOCOL_ERROR));
}
};
*request.headers_mut() = fields;
Ok(request)
}
}
// ===== impl Handshaking =====
impl<T, B> fmt::Debug for Handshaking<T, B>
where
B: Buf,
{
#[inline]
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
match *self {
Handshaking::Flushing(_) => f.write_str("Flushing(_)"),
Handshaking::ReadingPreface(_) => f.write_str("ReadingPreface(_)"),
Handshaking::Done => f.write_str("Done"),
}
}
}