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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std::cmp::Ordering;
use std::mem;
use std::time::Instant;
use crate::frame::{Frame, FrameType};
use crate::packet::PacketBuilder;
use crate::recovery::RecoveryToken;
use crate::{CloseError, ConnectionError};
#[derive(Clone, Debug, PartialEq, Eq)]
/// The state of the Connection.
pub enum State {
Init,
WaitInitial,
Handshaking,
Connected,
Confirmed,
Closing {
error: ConnectionError,
timeout: Instant,
},
Draining {
error: ConnectionError,
timeout: Instant,
},
Closed(ConnectionError),
}
impl State {
#[must_use]
pub fn connected(&self) -> bool {
matches!(self, Self::Connected | Self::Confirmed)
}
#[must_use]
pub fn closed(&self) -> bool {
matches!(self, Self::Closing { .. } | Self::Draining { .. } | Self::Closed(_))
}
}
// Implement `PartialOrd` so that we can enforce monotonic state progression.
impl PartialOrd for State {
#[allow(clippy::match_same_arms)] // Lint bug: rust-lang/rust-clippy#860
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
if mem::discriminant(self) == mem::discriminant(other) {
return Some(Ordering::Equal);
}
Some(match (self, other) {
(Self::Init, _) => Ordering::Less,
(_, Self::Init) => Ordering::Greater,
(Self::WaitInitial, _) => Ordering::Less,
(_, Self::WaitInitial) => Ordering::Greater,
(Self::Handshaking, _) => Ordering::Less,
(_, Self::Handshaking) => Ordering::Greater,
(Self::Connected, _) => Ordering::Less,
(_, Self::Connected) => Ordering::Greater,
(Self::Confirmed, _) => Ordering::Less,
(_, Self::Confirmed) => Ordering::Greater,
(Self::Closing { .. }, _) => Ordering::Less,
(_, Self::Closing { .. }) => Ordering::Greater,
(Self::Draining { .. }, _) => Ordering::Less,
(_, Self::Draining { .. }) => Ordering::Greater,
(Self::Closed(_), _) => unreachable!(),
})
}
}
impl Ord for State {
fn cmp(&self, other: &Self) -> Ordering {
if mem::discriminant(self) == mem::discriminant(other) {
return Ordering::Equal;
}
match (self, other) {
(Self::Init, _) => Ordering::Less,
(_, Self::Init) => Ordering::Greater,
(Self::WaitInitial, _) => Ordering::Less,
(_, Self::WaitInitial) => Ordering::Greater,
(Self::Handshaking, _) => Ordering::Less,
(_, Self::Handshaking) => Ordering::Greater,
(Self::Connected, _) => Ordering::Less,
(_, Self::Connected) => Ordering::Greater,
(Self::Confirmed, _) => Ordering::Less,
(_, Self::Confirmed) => Ordering::Greater,
(Self::Closing { .. }, _) => Ordering::Less,
(_, Self::Closing { .. }) => Ordering::Greater,
(Self::Draining { .. }, _) => Ordering::Less,
(_, Self::Draining { .. }) => Ordering::Greater,
(Self::Closed(_), _) => unreachable!(),
}
}
}
type ClosingFrame = Frame<'static>;
/// `StateSignaling` manages whether we need to send HANDSHAKE_DONE and CONNECTION_CLOSE.
/// Valid state transitions are:
/// * Idle -> HandshakeDone: at the server when the handshake completes
/// * HandshakeDone -> Idle: when a HANDSHAKE_DONE frame is sent
/// * Idle/HandshakeDone -> Closing/Draining: when closing or draining
/// * Closing/Draining -> CloseSent: after sending CONNECTION_CLOSE
/// * CloseSent -> Closing: any time a new CONNECTION_CLOSE is needed
/// * -> Reset: from any state in case of a stateless reset
#[derive(Debug, Clone, PartialEq)]
pub enum StateSignaling {
Idle,
HandshakeDone,
/// These states save the frame that needs to be sent.
Closing(ClosingFrame),
Draining(ClosingFrame),
/// This state saves the frame that might need to be sent again.
/// If it is `None`, then we are draining and don't send.
CloseSent(Option<ClosingFrame>),
Reset,
}
impl StateSignaling {
pub fn handshake_done(&mut self) {
if *self != Self::Idle {
debug_assert!(false, "StateSignaling must be in Idle state.");
return;
}
*self = Self::HandshakeDone
}
pub fn write_done(&mut self, builder: &mut PacketBuilder) -> Option<RecoveryToken> {
if *self == Self::HandshakeDone && builder.remaining() >= 1 {
*self = Self::Idle;
builder.encode_varint(Frame::HandshakeDone.get_type());
Some(RecoveryToken::HandshakeDone)
} else {
None
}
}
fn make_close_frame(
error: ConnectionError,
frame_type: FrameType,
message: impl AsRef<str>,
) -> ClosingFrame {
let reason_phrase = message.as_ref().as_bytes().to_owned();
Frame::ConnectionClose {
error_code: CloseError::from(error),
frame_type,
reason_phrase,
}
}
pub fn close(
&mut self,
error: ConnectionError,
frame_type: FrameType,
message: impl AsRef<str>,
) {
if *self != Self::Reset {
*self = Self::Closing(Self::make_close_frame(error, frame_type, message));
}
}
pub fn drain(
&mut self,
error: ConnectionError,
frame_type: FrameType,
message: impl AsRef<str>,
) {
if *self != Self::Reset {
*self = Self::Draining(Self::make_close_frame(error, frame_type, message));
}
}
/// If a close is pending, take a frame.
pub fn close_frame(&mut self) -> Option<ClosingFrame> {
match self {
Self::Closing(frame) => {
// When we are closing, we might need to send the close frame again.
let frame = mem::replace(frame, Frame::Padding);
*self = Self::CloseSent(Some(frame.clone()));
Some(frame)
}
Self::Draining(frame) => {
// When we are draining, just send once.
let frame = mem::replace(frame, Frame::Padding);
*self = Self::CloseSent(None);
Some(frame)
}
_ => None,
}
}
/// If a close can be sent again, prepare to send it again.
pub fn send_close(&mut self) {
if let Self::CloseSent(Some(frame)) = self {
let frame = mem::replace(frame, Frame::Padding);
*self = Self::Closing(frame);
}
}
/// We just got a stateless reset. Terminate.
pub fn reset(&mut self) {
*self = Self::Reset;
}
}
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