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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// Building a stream of ordered bytes to give the application from a series of
// incoming STREAM frames.
use std::{
cell::RefCell,
cmp::max,
collections::BTreeMap,
mem,
rc::{Rc, Weak},
};
use neqo_common::{qtrace, Role};
use smallvec::SmallVec;
use crate::{
events::ConnectionEvents,
fc::ReceiverFlowControl,
frame::FRAME_TYPE_STOP_SENDING,
packet::PacketBuilder,
recovery::{RecoveryToken, StreamRecoveryToken},
send_stream::SendStreams,
stats::FrameStats,
stream_id::StreamId,
AppError, Error, Res,
};
const RX_STREAM_DATA_WINDOW: u64 = 0x10_0000; // 1MiB
// Export as usize for consistency with SEND_BUFFER_SIZE
#[allow(clippy::cast_possible_truncation)] // Yeah, nope.
pub const RECV_BUFFER_SIZE: usize = RX_STREAM_DATA_WINDOW as usize;
#[derive(Debug, Default)]
pub struct RecvStreams {
streams: BTreeMap<StreamId, RecvStream>,
keep_alive: Weak<()>,
}
impl RecvStreams {
pub fn write_frames(
&mut self,
builder: &mut PacketBuilder,
tokens: &mut Vec<RecoveryToken>,
stats: &mut FrameStats,
) {
for stream in self.streams.values_mut() {
stream.write_frame(builder, tokens, stats);
if builder.is_full() {
return;
}
}
}
pub fn insert(&mut self, id: StreamId, stream: RecvStream) {
self.streams.insert(id, stream);
}
#[allow(clippy::missing_errors_doc)]
pub fn get_mut(&mut self, id: StreamId) -> Res<&mut RecvStream> {
self.streams.get_mut(&id).ok_or(Error::InvalidStreamId)
}
#[allow(clippy::missing_errors_doc)]
pub fn keep_alive(&mut self, id: StreamId, k: bool) -> Res<()> {
let self_ka = &mut self.keep_alive;
let s = self.streams.get_mut(&id).ok_or(Error::InvalidStreamId)?;
s.keep_alive = if k {
Some(self_ka.upgrade().unwrap_or_else(|| {
let r = Rc::new(());
*self_ka = Rc::downgrade(&r);
r
}))
} else {
None
};
Ok(())
}
#[must_use]
pub fn need_keep_alive(&self) -> bool {
self.keep_alive.strong_count() > 0
}
pub fn clear(&mut self) {
self.streams.clear();
}
pub fn clear_terminal(&mut self, send_streams: &SendStreams, role: Role) -> (u64, u64) {
let mut removed_bidi = 0;
let mut removed_uni = 0;
self.streams.retain(|id, s| {
let dead = s.is_terminal() && (id.is_uni() || !send_streams.exists(*id));
if dead && id.is_remote_initiated(role) {
if id.is_bidi() {
removed_bidi += 1;
} else {
removed_uni += 1;
}
}
!dead
});
(removed_bidi, removed_uni)
}
}
/// Holds data not yet read by application. Orders and dedupes data ranges
/// from incoming STREAM frames.
#[derive(Debug, Default)]
pub struct RxStreamOrderer {
data_ranges: BTreeMap<u64, Vec<u8>>, // (start_offset, data)
retired: u64, // Number of bytes the application has read
received: u64, // The number of bytes has stored in `data_ranges`
}
impl RxStreamOrderer {
#[must_use]
pub fn new() -> Self {
Self::default()
}
/// Process an incoming stream frame off the wire. This may result in data
/// being available to upper layers if frame is not out of order (ooo) or
/// if the frame fills a gap.
/// # Panics
/// Only when `u64` values cannot be converted to `usize`, which only
/// happens on 32-bit machines that hold far too much data at the same time.
pub fn inbound_frame(&mut self, mut new_start: u64, mut new_data: &[u8]) {
qtrace!("Inbound data offset={} len={}", new_start, new_data.len());
// Get entry before where new entry would go, so we can see if we already
// have the new bytes.
// Avoid copies and duplicated data.
let new_end = new_start + u64::try_from(new_data.len()).unwrap();
if new_end <= self.retired {
// Range already read by application, this frame is very late and unneeded.
return;
}
if new_start < self.retired {
new_data = &new_data[usize::try_from(self.retired - new_start).unwrap()..];
new_start = self.retired;
}
if new_data.is_empty() {
// No data to insert
return;
}
let extend = if let Some((&prev_start, prev_vec)) =
self.data_ranges.range_mut(..=new_start).next_back()
{
let prev_end = prev_start + u64::try_from(prev_vec.len()).unwrap();
if new_end > prev_end {
// PPPPPP -> PPPPPP
// NNNNNN NN
// NNNNNNNN NN
// Add a range containing only new data
// (In-order frames will take this path, with no overlap)
let overlap = prev_end.saturating_sub(new_start);
qtrace!(
"New frame {}-{} received, overlap: {}",
new_start,
new_end,
overlap
);
new_start += overlap;
new_data = &new_data[usize::try_from(overlap).unwrap()..];
// If it is small enough, extend the previous buffer.
// This can't always extend, because otherwise the buffer could end up
// growing indefinitely without being released.
prev_vec.len() < 4096 && prev_end == new_start
} else {
// PPPPPP -> PPPPPP
// NNNN
// NNNN
// Do nothing
qtrace!(
"Dropping frame with already-received range {}-{}",
new_start,
new_end
);
return;
}
} else {
qtrace!("New frame {}-{} received", new_start, new_end);
false
};
let mut to_add = new_data;
if self
.data_ranges
.last_entry()
.is_some_and(|e| *e.key() >= new_start)
{
// Is this at the end (common case)? If so, nothing to do in this block
// Common case:
// PPPPPP -> PPPPPP
// NNNNNNN NNNNNNN
// or
// PPPPPP -> PPPPPP
// NNNNNNN NNNNNNN
//
// Not the common case, handle possible overlap with next entries
// PPPPPP AAA -> PPPPPP
// NNNNNNN NNNNNNN
// or
// PPPPPP AAAA -> PPPPPP AAAA
// NNNNNNN NNNNN
// or (this is where to_remove is used)
// PPPPPP AA -> PPPPPP
// NNNNNNN NNNNNNN
let mut to_remove = SmallVec::<[_; 8]>::new();
for (&next_start, next_data) in self.data_ranges.range_mut(new_start..) {
let next_end = next_start + u64::try_from(next_data.len()).unwrap();
let overlap = new_end.saturating_sub(next_start);
if overlap == 0 {
// Fills in the hole, exactly (probably common)
break;
} else if next_end >= new_end {
qtrace!(
"New frame {}-{} overlaps with next frame by {}, truncating",
new_start,
new_end,
overlap
);
let truncate_to = new_data.len() - usize::try_from(overlap).unwrap();
to_add = &new_data[..truncate_to];
break;
}
qtrace!(
"New frame {}-{} spans entire next frame {}-{}, replacing",
new_start,
new_end,
next_start,
next_end
);
to_remove.push(next_start);
// Continue, since we may have more overlaps
}
for start in to_remove {
self.data_ranges.remove(&start);
}
}
if !to_add.is_empty() {
self.received += u64::try_from(to_add.len()).unwrap();
if extend {
let (_, buf) = self
.data_ranges
.range_mut(..=new_start)
.next_back()
.unwrap();
buf.extend_from_slice(to_add);
} else {
self.data_ranges.insert(new_start, to_add.to_vec());
}
}
}
/// Are any bytes readable?
#[must_use]
pub fn data_ready(&self) -> bool {
self.data_ranges
.keys()
.next()
.is_some_and(|&start| start <= self.retired)
}
/// How many bytes are readable?
fn bytes_ready(&self) -> usize {
let mut prev_end = self.retired;
self.data_ranges
.iter()
.map(|(start_offset, data)| {
// All ranges don't overlap but we could have partially
// retired some of the first entry's data.
let data_len = data.len() as u64 - self.retired.saturating_sub(*start_offset);
(start_offset, data_len)
})
.take_while(|(start_offset, data_len)| {
if **start_offset <= prev_end {
prev_end += data_len;
true
} else {
false
}
})
// Accumulate, but saturate at usize::MAX.
.fold(0, |acc: usize, (_, data_len)| {
acc.saturating_add(usize::try_from(data_len).unwrap_or(usize::MAX))
})
}
/// Bytes read by the application.
#[must_use]
pub const fn retired(&self) -> u64 {
self.retired
}
#[must_use]
pub const fn received(&self) -> u64 {
self.received
}
/// Data bytes buffered. Could be more than `bytes_readable` if there are
/// ranges missing.
fn buffered(&self) -> u64 {
self.data_ranges
.iter()
.map(|(&start, data)| data.len() as u64 - (self.retired.saturating_sub(start)))
.sum()
}
/// Copy received data (if any) into the buffer. Returns bytes copied.
fn read(&mut self, buf: &mut [u8]) -> usize {
qtrace!("Reading {} bytes, {} available", buf.len(), self.buffered());
let mut copied = 0;
for (&range_start, range_data) in &mut self.data_ranges {
let mut keep = false;
if self.retired >= range_start {
// Frame data has new contiguous bytes.
let copy_offset =
usize::try_from(max(range_start, self.retired) - range_start).unwrap();
assert!(range_data.len() >= copy_offset);
let available = range_data.len() - copy_offset;
let space = buf.len() - copied;
let copy_bytes = if available > space {
keep = true;
space
} else {
available
};
if copy_bytes > 0 {
let copy_slc = &range_data[copy_offset..copy_offset + copy_bytes];
buf[copied..copied + copy_bytes].copy_from_slice(copy_slc);
copied += copy_bytes;
self.retired += u64::try_from(copy_bytes).unwrap();
}
} else {
// The data in the buffer isn't contiguous.
keep = true;
}
if keep {
let mut keep = self.data_ranges.split_off(&range_start);
mem::swap(&mut self.data_ranges, &mut keep);
return copied;
}
}
self.data_ranges.clear();
copied
}
/// Extend the given Vector with any available data.
pub fn read_to_end(&mut self, buf: &mut Vec<u8>) -> usize {
let orig_len = buf.len();
buf.resize(orig_len + self.bytes_ready(), 0);
self.read(&mut buf[orig_len..])
}
}
/// QUIC receiving states, based on -transport 3.2.
#[derive(Debug)]
// Because a dead_code warning is easier than clippy::unused_self, see https://github.com/rust-lang/rust/issues/68408
enum RecvStreamState {
Recv {
fc: ReceiverFlowControl<StreamId>,
session_fc: Rc<RefCell<ReceiverFlowControl<()>>>,
recv_buf: RxStreamOrderer,
},
SizeKnown {
fc: ReceiverFlowControl<StreamId>,
session_fc: Rc<RefCell<ReceiverFlowControl<()>>>,
recv_buf: RxStreamOrderer,
},
DataRecvd {
fc: ReceiverFlowControl<StreamId>,
session_fc: Rc<RefCell<ReceiverFlowControl<()>>>,
recv_buf: RxStreamOrderer,
},
DataRead {
final_received: u64,
final_read: u64,
},
AbortReading {
fc: ReceiverFlowControl<StreamId>,
session_fc: Rc<RefCell<ReceiverFlowControl<()>>>,
final_size_reached: bool,
frame_needed: bool,
err: AppError,
final_received: u64,
final_read: u64,
},
WaitForReset {
fc: ReceiverFlowControl<StreamId>,
session_fc: Rc<RefCell<ReceiverFlowControl<()>>>,
final_received: u64,
final_read: u64,
},
ResetRecvd {
final_received: u64,
final_read: u64,
},
// Defined by spec but we don't use it: ResetRead
}
impl RecvStreamState {
fn new(
max_bytes: u64,
stream_id: StreamId,
session_fc: Rc<RefCell<ReceiverFlowControl<()>>>,
) -> Self {
Self::Recv {
fc: ReceiverFlowControl::new(stream_id, max_bytes),
recv_buf: RxStreamOrderer::new(),
session_fc,
}
}
const fn name(&self) -> &str {
match self {
Self::Recv { .. } => "Recv",
Self::SizeKnown { .. } => "SizeKnown",
Self::DataRecvd { .. } => "DataRecvd",
Self::DataRead { .. } => "DataRead",
Self::AbortReading { .. } => "AbortReading",
Self::WaitForReset { .. } => "WaitForReset",
Self::ResetRecvd { .. } => "ResetRecvd",
}
}
const fn recv_buf(&self) -> Option<&RxStreamOrderer> {
match self {
Self::Recv { recv_buf, .. }
| Self::SizeKnown { recv_buf, .. }
| Self::DataRecvd { recv_buf, .. } => Some(recv_buf),
Self::DataRead { .. }
| Self::AbortReading { .. }
| Self::WaitForReset { .. }
| Self::ResetRecvd { .. } => None,
}
}
fn flow_control_consume_data(&mut self, consumed: u64, fin: bool) -> Res<()> {
let (fc, session_fc, final_size_reached, retire_data) = match self {
Self::Recv { fc, session_fc, .. } => (fc, session_fc, false, false),
Self::WaitForReset { fc, session_fc, .. } => (fc, session_fc, false, true),
Self::SizeKnown { fc, session_fc, .. } | Self::DataRecvd { fc, session_fc, .. } => {
(fc, session_fc, true, false)
}
Self::AbortReading {
fc,
session_fc,
final_size_reached,
..
} => {
let old_final_size_reached = *final_size_reached;
*final_size_reached |= fin;
(fc, session_fc, old_final_size_reached, true)
}
Self::DataRead { .. } | Self::ResetRecvd { .. } => {
return Ok(());
}
};
// Check final size:
let final_size_ok = match (fin, final_size_reached) {
(true, true) => consumed == fc.consumed(),
(false, true) => consumed <= fc.consumed(),
(true, false) => consumed >= fc.consumed(),
(false, false) => true,
};
if !final_size_ok {
return Err(Error::FinalSizeError);
}
let new_bytes_consumed = fc.set_consumed(consumed)?;
session_fc.borrow_mut().consume(new_bytes_consumed)?;
if retire_data {
// Let's also retire this data since the stream has been aborted
RecvStream::flow_control_retire_data(fc.consumed() - fc.retired(), fc, session_fc);
}
Ok(())
}
}
#[derive(Debug, Clone, Copy)]
pub struct RecvStreamStats {
// An indicator of progress on how many of the server application’s bytes
// intended for this stream have been received so far.
// Only sequential bytes up to, but not including, the first missing byte,
// are counted. This number can only increase.
pub bytes_received: u64,
// The total number of bytes the application has successfully read from this
// stream. This number can only increase, and is always less than or equal
// to bytes_received.
pub bytes_read: u64,
}
impl RecvStreamStats {
#[must_use]
pub const fn new(bytes_received: u64, bytes_read: u64) -> Self {
Self {
bytes_received,
bytes_read,
}
}
#[must_use]
pub const fn bytes_received(&self) -> u64 {
self.bytes_received
}
#[must_use]
pub const fn bytes_read(&self) -> u64 {
self.bytes_read
}
}
/// Implement a QUIC receive stream.
#[derive(Debug)]
pub struct RecvStream {
stream_id: StreamId,
state: RecvStreamState,
conn_events: ConnectionEvents,
keep_alive: Option<Rc<()>>,
}
impl RecvStream {
pub fn new(
stream_id: StreamId,
max_stream_data: u64,
session_fc: Rc<RefCell<ReceiverFlowControl<()>>>,
conn_events: ConnectionEvents,
) -> Self {
Self {
stream_id,
state: RecvStreamState::new(max_stream_data, stream_id, session_fc),
conn_events,
keep_alive: None,
}
}
fn set_state(&mut self, new_state: RecvStreamState) {
debug_assert_ne!(
mem::discriminant(&self.state),
mem::discriminant(&new_state)
);
qtrace!(
"RecvStream {} state {} -> {}",
self.stream_id.as_u64(),
self.state.name(),
new_state.name()
);
match new_state {
// Receiving all data, or receiving or requesting RESET_STREAM
// is cause to stop keep-alives.
RecvStreamState::DataRecvd { .. }
| RecvStreamState::AbortReading { .. }
| RecvStreamState::ResetRecvd { .. } => {
self.keep_alive = None;
}
// Once all the data is read, generate an event.
RecvStreamState::DataRead { .. } => {
self.conn_events.recv_stream_complete(self.stream_id);
}
_ => {}
}
self.state = new_state;
}
#[must_use]
pub const fn stats(&self) -> RecvStreamStats {
match &self.state {
RecvStreamState::Recv { recv_buf, .. }
| RecvStreamState::SizeKnown { recv_buf, .. }
| RecvStreamState::DataRecvd { recv_buf, .. } => {
let received = recv_buf.received();
let read = recv_buf.retired();
RecvStreamStats::new(received, read)
}
RecvStreamState::AbortReading {
final_received,
final_read,
..
}
| RecvStreamState::WaitForReset {
final_received,
final_read,
..
}
| RecvStreamState::DataRead {
final_received,
final_read,
}
| RecvStreamState::ResetRecvd {
final_received,
final_read,
} => {
let received = *final_received;
let read = *final_read;
RecvStreamStats::new(received, read)
}
}
}
/// # Errors
/// When the incoming data violates flow control limits.
/// # Panics
/// Only when `u64` values are so big that they can't fit in a `usize`, which
/// only happens on a 32-bit machine that has far too much unread data.
pub fn inbound_stream_frame(&mut self, fin: bool, offset: u64, data: &[u8]) -> Res<()> {
// We should post a DataReadable event only once when we change from no-data-ready to
// data-ready. Therefore remember the state before processing a new frame.
let already_data_ready = self.data_ready();
let new_end = offset + u64::try_from(data.len())?;
self.state.flow_control_consume_data(new_end, fin)?;
match &mut self.state {
RecvStreamState::Recv {
recv_buf,
fc,
session_fc,
} => {
recv_buf.inbound_frame(offset, data);
if fin {
let all_recv =
fc.consumed() == recv_buf.retired() + recv_buf.bytes_ready() as u64;
let buf = mem::replace(recv_buf, RxStreamOrderer::new());
let fc_copy = mem::take(fc);
let session_fc_copy = mem::take(session_fc);
if all_recv {
self.set_state(RecvStreamState::DataRecvd {
fc: fc_copy,
session_fc: session_fc_copy,
recv_buf: buf,
});
} else {
self.set_state(RecvStreamState::SizeKnown {
fc: fc_copy,
session_fc: session_fc_copy,
recv_buf: buf,
});
}
}
}
RecvStreamState::SizeKnown {
recv_buf,
fc,
session_fc,
} => {
recv_buf.inbound_frame(offset, data);
if fc.consumed() == recv_buf.retired() + recv_buf.bytes_ready() as u64 {
let buf = mem::replace(recv_buf, RxStreamOrderer::new());
let fc_copy = mem::take(fc);
let session_fc_copy = mem::take(session_fc);
self.set_state(RecvStreamState::DataRecvd {
fc: fc_copy,
session_fc: session_fc_copy,
recv_buf: buf,
});
}
}
RecvStreamState::DataRecvd { .. }
| RecvStreamState::DataRead { .. }
| RecvStreamState::AbortReading { .. }
| RecvStreamState::WaitForReset { .. }
| RecvStreamState::ResetRecvd { .. } => {
qtrace!("data received when we are in state {}", self.state.name());
}
}
if !already_data_ready && (self.data_ready() || self.needs_to_inform_app_about_fin()) {
self.conn_events.recv_stream_readable(self.stream_id);
}
Ok(())
}
/// # Errors
/// When the reset occurs at an invalid point.
pub fn reset(&mut self, application_error_code: AppError, final_size: u64) -> Res<()> {
self.state.flow_control_consume_data(final_size, true)?;
match &mut self.state {
RecvStreamState::Recv {
fc,
session_fc,
recv_buf,
}
| RecvStreamState::SizeKnown {
fc,
session_fc,
recv_buf,
} => {
// make flow control consumes new data that not really exist.
Self::flow_control_retire_data(final_size - fc.retired(), fc, session_fc);
self.conn_events
.recv_stream_reset(self.stream_id, application_error_code);
let received = recv_buf.received();
let read = recv_buf.retired();
self.set_state(RecvStreamState::ResetRecvd {
final_received: received,
final_read: read,
});
}
RecvStreamState::AbortReading {
fc,
session_fc,
final_received,
final_read,
..
}
| RecvStreamState::WaitForReset {
fc,
session_fc,
final_received,
final_read,
} => {
// make flow control consumes new data that not really exist.
Self::flow_control_retire_data(final_size - fc.retired(), fc, session_fc);
self.conn_events
.recv_stream_reset(self.stream_id, application_error_code);
let received = *final_received;
let read = *final_read;
self.set_state(RecvStreamState::ResetRecvd {
final_received: received,
final_read: read,
});
}
_ => {
// Ignore reset if in DataRecvd, DataRead, or ResetRecvd
}
}
Ok(())
}
/// If we should tell the sender they have more credit, return an offset
fn flow_control_retire_data(
new_read: u64,
fc: &mut ReceiverFlowControl<StreamId>,
session_fc: &Rc<RefCell<ReceiverFlowControl<()>>>,
) {
if new_read > 0 {
fc.add_retired(new_read);
session_fc.borrow_mut().add_retired(new_read);
}
}
/// Send a flow control update.
/// This is used when a peer declares that they are blocked.
/// This sends `MAX_STREAM_DATA` if there is any increase possible.
pub fn send_flowc_update(&mut self) {
if let RecvStreamState::Recv { fc, .. } = &mut self.state {
fc.send_flowc_update();
}
}
pub fn set_stream_max_data(&mut self, max_data: u64) {
if let RecvStreamState::Recv { fc, .. } = &mut self.state {
fc.set_max_active(max_data);
}
}
#[must_use]
pub const fn is_terminal(&self) -> bool {
matches!(
self.state,
RecvStreamState::ResetRecvd { .. } | RecvStreamState::DataRead { .. }
)
}
// App got all data but did not get the fin signal.
const fn needs_to_inform_app_about_fin(&self) -> bool {
matches!(self.state, RecvStreamState::DataRecvd { .. })
}
fn data_ready(&self) -> bool {
self.state
.recv_buf()
.is_some_and(RxStreamOrderer::data_ready)
}
/// # Errors
/// `NoMoreData` if data and fin bit were previously read by the application.
#[allow(clippy::missing_panics_doc)] // with a >16 exabyte packet on a 128-bit machine, maybe
pub fn read(&mut self, buf: &mut [u8]) -> Res<(usize, bool)> {
let data_recvd_state = matches!(self.state, RecvStreamState::DataRecvd { .. });
match &mut self.state {
RecvStreamState::Recv {
recv_buf,
fc,
session_fc,
}
| RecvStreamState::SizeKnown {
recv_buf,
fc,
session_fc,
..
}
| RecvStreamState::DataRecvd {
recv_buf,
fc,
session_fc,
} => {
let bytes_read = recv_buf.read(buf);
Self::flow_control_retire_data(u64::try_from(bytes_read).unwrap(), fc, session_fc);
let fin_read = if data_recvd_state {
if recv_buf.buffered() == 0 {
let received = recv_buf.received();
let read = recv_buf.retired();
self.set_state(RecvStreamState::DataRead {
final_received: received,
final_read: read,
});
true
} else {
false
}
} else {
false
};
Ok((bytes_read, fin_read))
}
RecvStreamState::DataRead { .. }
| RecvStreamState::AbortReading { .. }
| RecvStreamState::WaitForReset { .. }
| RecvStreamState::ResetRecvd { .. } => Err(Error::NoMoreData),
}
}
pub fn stop_sending(&mut self, err: AppError) {
qtrace!("stop_sending called when in state {}", self.state.name());
match &mut self.state {
RecvStreamState::Recv {
fc,
session_fc,
recv_buf,
}
| RecvStreamState::SizeKnown {
fc,
session_fc,
recv_buf,
} => {
// Retire data
Self::flow_control_retire_data(fc.consumed() - fc.retired(), fc, session_fc);
let fc_copy = mem::take(fc);
let session_fc_copy = mem::take(session_fc);
let received = recv_buf.received();
let read = recv_buf.retired();
self.set_state(RecvStreamState::AbortReading {
fc: fc_copy,
session_fc: session_fc_copy,
final_size_reached: matches!(self.state, RecvStreamState::SizeKnown { .. }),
frame_needed: true,
err,
final_received: received,
final_read: read,
});
}
RecvStreamState::DataRecvd {
fc,
session_fc,
recv_buf,
} => {
Self::flow_control_retire_data(fc.consumed() - fc.retired(), fc, session_fc);
let received = recv_buf.received();
let read = recv_buf.retired();
self.set_state(RecvStreamState::DataRead {
final_received: received,
final_read: read,
});
}
RecvStreamState::DataRead { .. }
| RecvStreamState::AbortReading { .. }
| RecvStreamState::WaitForReset { .. }
| RecvStreamState::ResetRecvd { .. } => {
// Already in terminal state
}
}
}
/// Maybe write a `MAX_STREAM_DATA` frame.
pub fn write_frame(
&mut self,
builder: &mut PacketBuilder,
tokens: &mut Vec<RecoveryToken>,
stats: &mut FrameStats,
) {
match &mut self.state {
// Maybe send MAX_STREAM_DATA
RecvStreamState::Recv { fc, .. } => fc.write_frames(builder, tokens, stats),
// Maybe send STOP_SENDING
RecvStreamState::AbortReading {
frame_needed, err, ..
} => {
if *frame_needed
&& builder.write_varint_frame(&[
FRAME_TYPE_STOP_SENDING,
self.stream_id.as_u64(),
*err,
])
{
tokens.push(RecoveryToken::Stream(StreamRecoveryToken::StopSending {
stream_id: self.stream_id,
}));
stats.stop_sending += 1;
*frame_needed = false;
}
}
_ => {}
}
}
pub fn max_stream_data_lost(&mut self, maximum_data: u64) {
if let RecvStreamState::Recv { fc, .. } = &mut self.state {
fc.frame_lost(maximum_data);
}
}
pub fn stop_sending_lost(&mut self) {
if let RecvStreamState::AbortReading { frame_needed, .. } = &mut self.state {
*frame_needed = true;
}
}
pub fn stop_sending_acked(&mut self) {
if let RecvStreamState::AbortReading {
fc,
session_fc,
final_size_reached,
final_received,
final_read,
..
} = &mut self.state
{
let received = *final_received;
let read = *final_read;
if *final_size_reached {
// We already know the final_size of the stream therefore we
// do not need to wait for RESET.
self.set_state(RecvStreamState::ResetRecvd {
final_received: received,
final_read: read,
});
} else {
let fc_copy = mem::take(fc);
let session_fc_copy = mem::take(session_fc);
self.set_state(RecvStreamState::WaitForReset {
fc: fc_copy,
session_fc: session_fc_copy,
final_received: received,
final_read: read,
});
}
}
}
#[cfg(test)]
#[must_use]
pub const fn has_frames_to_write(&self) -> bool {
if let RecvStreamState::Recv { fc, .. } = &self.state {
fc.frame_needed()
} else {
false
}
}
#[cfg(test)]
#[must_use]
pub const fn fc(&self) -> Option<&ReceiverFlowControl<StreamId>> {
match &self.state {
RecvStreamState::Recv { fc, .. }
| RecvStreamState::SizeKnown { fc, .. }
| RecvStreamState::DataRecvd { fc, .. }
| RecvStreamState::AbortReading { fc, .. }
| RecvStreamState::WaitForReset { fc, .. } => Some(fc),
_ => None,
}
}
}
#[cfg(test)]
mod tests {
use std::{cell::RefCell, ops::Range, rc::Rc};
use neqo_common::{qtrace, Encoder};
use super::RecvStream;
use crate::{
fc::ReceiverFlowControl,
packet::PacketBuilder,
recv_stream::{RxStreamOrderer, RX_STREAM_DATA_WINDOW},
stats::FrameStats,
ConnectionEvents, Error, StreamId, RECV_BUFFER_SIZE,
};
const SESSION_WINDOW: usize = 1024;
fn recv_ranges(ranges: &[Range<u64>], available: usize) {
const ZEROES: &[u8] = &[0; 100];
qtrace!("recv_ranges {:?}", ranges);
let mut s = RxStreamOrderer::default();
for r in ranges {
let data = &ZEROES[..usize::try_from(r.end - r.start).unwrap()];
s.inbound_frame(r.start, data);
}
let mut buf = [0xff; 100];
let mut total_recvd = 0;
loop {
let recvd = s.read(&mut buf[..]);
qtrace!("recv_ranges read {}", recvd);
total_recvd += recvd;
if recvd == 0 {
assert_eq!(total_recvd, available);
break;
}
}
}
#[test]
#[allow(clippy::single_range_in_vec_init)] // Because that lint makes no sense here.
fn recv_noncontiguous() {
// Non-contiguous with the start, no data available.
recv_ranges(&[10..20], 0);
}
/// Overlaps with the start of a 10..20 range of bytes.
#[test]
fn recv_overlap_start() {
// Overlap the start, with a larger new value.
// More overlap than not.
recv_ranges(&[10..20, 4..18, 0..4], 20);
// Overlap the start, with a larger new value.
// Less overlap than not.
recv_ranges(&[10..20, 2..15, 0..2], 20);
// Overlap the start, with a smaller new value.
// More overlap than not.
recv_ranges(&[10..20, 8..14, 0..8], 20);
// Overlap the start, with a smaller new value.
// Less overlap than not.
recv_ranges(&[10..20, 6..13, 0..6], 20);
// Again with some of the first range split in two.
recv_ranges(&[10..11, 11..20, 4..18, 0..4], 20);
recv_ranges(&[10..11, 11..20, 2..15, 0..2], 20);
recv_ranges(&[10..11, 11..20, 8..14, 0..8], 20);
recv_ranges(&[10..11, 11..20, 6..13, 0..6], 20);
// Again with a gap in the first range.
recv_ranges(&[10..11, 12..20, 4..18, 0..4], 20);
recv_ranges(&[10..11, 12..20, 2..15, 0..2], 20);
recv_ranges(&[10..11, 12..20, 8..14, 0..8], 20);
recv_ranges(&[10..11, 12..20, 6..13, 0..6], 20);
}
/// Overlaps with the end of a 10..20 range of bytes.
#[test]
fn recv_overlap_end() {
// Overlap the end, with a larger new value.
// More overlap than not.
recv_ranges(&[10..20, 12..25, 0..10], 25);
// Overlap the end, with a larger new value.
// Less overlap than not.
recv_ranges(&[10..20, 17..33, 0..10], 33);
// Overlap the end, with a smaller new value.
// More overlap than not.
recv_ranges(&[10..20, 15..21, 0..10], 21);
// Overlap the end, with a smaller new value.
// Less overlap than not.
recv_ranges(&[10..20, 17..25, 0..10], 25);
// Again with some of the first range split in two.
recv_ranges(&[10..19, 19..20, 12..25, 0..10], 25);
recv_ranges(&[10..19, 19..20, 17..33, 0..10], 33);
recv_ranges(&[10..19, 19..20, 15..21, 0..10], 21);
recv_ranges(&[10..19, 19..20, 17..25, 0..10], 25);
// Again with a gap in the first range.
recv_ranges(&[10..18, 19..20, 12..25, 0..10], 25);
recv_ranges(&[10..18, 19..20, 17..33, 0..10], 33);
recv_ranges(&[10..18, 19..20, 15..21, 0..10], 21);
recv_ranges(&[10..18, 19..20, 17..25, 0..10], 25);
}
/// Complete overlaps with the start of a 10..20 range of bytes.
#[test]
fn recv_overlap_complete() {
// Complete overlap, more at the end.
recv_ranges(&[10..20, 9..23, 0..9], 23);
// Complete overlap, more at the start.
recv_ranges(&[10..20, 3..23, 0..3], 23);
// Complete overlap, to end.
recv_ranges(&[10..20, 5..20, 0..5], 20);
// Complete overlap, from start.
recv_ranges(&[10..20, 10..27, 0..10], 27);
// Complete overlap, from 0 and more.
recv_ranges(&[10..20, 0..23], 23);
// Again with the first range split in two.
recv_ranges(&[10..14, 14..20, 9..23, 0..9], 23);
recv_ranges(&[10..14, 14..20, 3..23, 0..3], 23);
recv_ranges(&[10..14, 14..20, 5..20, 0..5], 20);
recv_ranges(&[10..14, 14..20, 10..27, 0..10], 27);
recv_ranges(&[10..14, 14..20, 0..23], 23);
// Again with the a gap in the first range.
recv_ranges(&[10..13, 14..20, 9..23, 0..9], 23);
recv_ranges(&[10..13, 14..20, 3..23, 0..3], 23);
recv_ranges(&[10..13, 14..20, 5..20, 0..5], 20);
recv_ranges(&[10..13, 14..20, 10..27, 0..10], 27);
recv_ranges(&[10..13, 14..20, 0..23], 23);
}
/// An overlap with no new bytes.
#[test]
fn recv_overlap_duplicate() {
recv_ranges(&[10..20, 11..12, 0..10], 20);
recv_ranges(&[10..20, 10..15, 0..10], 20);
recv_ranges(&[10..20, 14..20, 0..10], 20);
// Now with the first range split.
recv_ranges(&[10..14, 14..20, 10..15, 0..10], 20);
recv_ranges(&[10..15, 16..20, 21..25, 10..25, 0..10], 25);
}
/// Reading exactly one chunk works, when the next chunk starts immediately.
#[test]
fn stop_reading_at_chunk() {
const CHUNK_SIZE: usize = 10;
const EXTRA_SIZE: usize = 3;
let mut s = RxStreamOrderer::new();
// Add three chunks.
s.inbound_frame(0, &[0; CHUNK_SIZE]);
let offset = u64::try_from(CHUNK_SIZE).unwrap();
s.inbound_frame(offset, &[0; EXTRA_SIZE]);
let offset = u64::try_from(CHUNK_SIZE + EXTRA_SIZE).unwrap();
s.inbound_frame(offset, &[0; EXTRA_SIZE]);
// Read, providing only enough space for the first.
let mut buf = [0; 100];
let count = s.read(&mut buf[..CHUNK_SIZE]);
assert_eq!(count, CHUNK_SIZE);
let count = s.read(&mut buf[..]);
assert_eq!(count, EXTRA_SIZE * 2);
}
#[test]
fn recv_overlap_while_reading() {
let mut s = RxStreamOrderer::new();
// Add a chunk
s.inbound_frame(0, &[0; 150]);
assert_eq!(s.data_ranges.get(&0).unwrap().len(), 150);
// Read, providing only enough space for the first 100.
let mut buf = [0; 100];
let count = s.read(&mut buf[..]);
assert_eq!(count, 100);
assert_eq!(s.retired, 100);
// Add a second frame that overlaps.
// This shouldn't truncate the first frame, as we're already
// Reading from it.
s.inbound_frame(120, &[0; 60]);
assert_eq!(s.data_ranges.get(&0).unwrap().len(), 180);
// Read second part of first frame and all of the second frame
let count = s.read(&mut buf[..]);
assert_eq!(count, 80);
}
/// Reading exactly one chunk works, when there is a gap.
#[test]
fn stop_reading_at_gap() {
const CHUNK_SIZE: usize = 10;
const EXTRA_SIZE: usize = 3;
let mut s = RxStreamOrderer::new();
// Add three chunks.
s.inbound_frame(0, &[0; CHUNK_SIZE]);
let offset = u64::try_from(CHUNK_SIZE + EXTRA_SIZE).unwrap();
s.inbound_frame(offset, &[0; EXTRA_SIZE]);
// Read, providing only enough space for the first chunk.
let mut buf = [0; 100];
let count = s.read(&mut buf[..CHUNK_SIZE]);
assert_eq!(count, CHUNK_SIZE);
// Now fill the gap and ensure that everything can be read.
let offset = u64::try_from(CHUNK_SIZE).unwrap();
s.inbound_frame(offset, &[0; EXTRA_SIZE]);
let count = s.read(&mut buf[..]);
assert_eq!(count, EXTRA_SIZE * 2);
}
/// Reading exactly one chunk works, when there is a gap.
#[test]
fn stop_reading_in_chunk() {
const CHUNK_SIZE: usize = 10;
const EXTRA_SIZE: usize = 3;
let mut s = RxStreamOrderer::new();
// Add two chunks.
s.inbound_frame(0, &[0; CHUNK_SIZE]);
let offset = u64::try_from(CHUNK_SIZE).unwrap();
s.inbound_frame(offset, &[0; EXTRA_SIZE]);
// Read, providing only enough space for some of the first chunk.
let mut buf = [0; 100];
let count = s.read(&mut buf[..CHUNK_SIZE - EXTRA_SIZE]);
assert_eq!(count, CHUNK_SIZE - EXTRA_SIZE);
let count = s.read(&mut buf[..]);
assert_eq!(count, EXTRA_SIZE * 2);
}
/// Read one byte at a time.
#[test]
fn read_byte_at_a_time() {
const CHUNK_SIZE: usize = 10;
const EXTRA_SIZE: usize = 3;
let mut s = RxStreamOrderer::new();
// Add two chunks.
s.inbound_frame(0, &[0; CHUNK_SIZE]);
let offset = u64::try_from(CHUNK_SIZE).unwrap();
s.inbound_frame(offset, &[0; EXTRA_SIZE]);
let mut buf = [0; 1];
for _ in 0..CHUNK_SIZE + EXTRA_SIZE {
let count = s.read(&mut buf[..]);
assert_eq!(count, 1);
}
assert_eq!(0, s.read(&mut buf[..]));
}
fn check_stats(stream: &RecvStream, expected_received: u64, expected_read: u64) {
let stream_stats = stream.stats();
assert_eq!(expected_received, stream_stats.bytes_received());
assert_eq!(expected_read, stream_stats.bytes_read());
}
#[test]
fn stream_rx() {
let conn_events = ConnectionEvents::default();
let mut s = RecvStream::new(
StreamId::from(567),
1024,
Rc::new(RefCell::new(ReceiverFlowControl::new((), 1024 * 1024))),
conn_events,
);
// test receiving a contig frame and reading it works
s.inbound_stream_frame(false, 0, &[1; 10]).unwrap();
assert!(s.data_ready());
check_stats(&s, 10, 0);
let mut buf = vec![0u8; 100];
assert_eq!(s.read(&mut buf).unwrap(), (10, false));
assert_eq!(s.state.recv_buf().unwrap().retired(), 10);
assert_eq!(s.state.recv_buf().unwrap().buffered(), 0);
check_stats(&s, 10, 10);
// test receiving a noncontig frame
s.inbound_stream_frame(false, 12, &[2; 12]).unwrap();
assert!(!s.data_ready());
assert_eq!(s.read(&mut buf).unwrap(), (0, false));
assert_eq!(s.state.recv_buf().unwrap().retired(), 10);
assert_eq!(s.state.recv_buf().unwrap().buffered(), 12);
check_stats(&s, 22, 10);
// another frame that overlaps the first
s.inbound_stream_frame(false, 14, &[3; 8]).unwrap();
assert!(!s.data_ready());
assert_eq!(s.state.recv_buf().unwrap().retired(), 10);
assert_eq!(s.state.recv_buf().unwrap().buffered(), 12);
check_stats(&s, 22, 10);
// fill in the gap, but with a FIN
s.inbound_stream_frame(true, 10, &[4; 6]).unwrap_err();
assert!(!s.data_ready());
assert_eq!(s.read(&mut buf).unwrap(), (0, false));
assert_eq!(s.state.recv_buf().unwrap().retired(), 10);
assert_eq!(s.state.recv_buf().unwrap().buffered(), 12);
check_stats(&s, 22, 10);
// fill in the gap
s.inbound_stream_frame(false, 10, &[5; 10]).unwrap();
assert!(s.data_ready());
assert_eq!(s.state.recv_buf().unwrap().retired(), 10);
assert_eq!(s.state.recv_buf().unwrap().buffered(), 14);
check_stats(&s, 24, 10);
// a legit FIN
s.inbound_stream_frame(true, 24, &[6; 18]).unwrap();
assert_eq!(s.state.recv_buf().unwrap().retired(), 10);
assert_eq!(s.state.recv_buf().unwrap().buffered(), 32);
assert!(s.data_ready());
assert_eq!(s.read(&mut buf).unwrap(), (32, true));
check_stats(&s, 42, 42);
// Stream now no longer readable (is in DataRead state)
s.read(&mut buf).unwrap_err();
}
fn check_chunks(s: &RxStreamOrderer, expected: &[(u64, usize)]) {
assert_eq!(s.data_ranges.len(), expected.len());
for ((start, buf), (expected_start, expected_len)) in s.data_ranges.iter().zip(expected) {
assert_eq!((*start, buf.len()), (*expected_start, *expected_len));
}
}
// Test deduplication when the new data is at the end.
#[test]
fn stream_rx_dedupe_tail() {
let mut s = RxStreamOrderer::new();
s.inbound_frame(0, &[1; 6]);
check_chunks(&s, &[(0, 6)]);
// New data that overlaps entirely (starting from the head), is ignored.
s.inbound_frame(0, &[2; 3]);
check_chunks(&s, &[(0, 6)]);
// New data that overlaps at the tail has any new data appended.
s.inbound_frame(2, &[3; 6]);
check_chunks(&s, &[(0, 8)]);
// New data that overlaps entirely (up to the tail), is ignored.
s.inbound_frame(4, &[4; 4]);
check_chunks(&s, &[(0, 8)]);
// New data that overlaps, starting from the beginning is appended too.
s.inbound_frame(0, &[5; 10]);
check_chunks(&s, &[(0, 10)]);
// New data that is entirely subsumed is ignored.
s.inbound_frame(2, &[6; 2]);
check_chunks(&s, &[(0, 10)]);
let mut buf = [0; 16];
assert_eq!(s.read(&mut buf[..]), 10);
assert_eq!(buf[..10], [1, 1, 1, 1, 1, 1, 3, 3, 5, 5]);
}
/// When chunks are added before existing data, they aren't merged.
#[test]
fn stream_rx_dedupe_head() {
let mut s = RxStreamOrderer::new();
s.inbound_frame(1, &[6; 6]);
check_chunks(&s, &[(1, 6)]);
// Insertion before an existing chunk causes truncation of the new chunk.
s.inbound_frame(0, &[7; 6]);
check_chunks(&s, &[(0, 1), (1, 6)]);
// Perfect overlap with existing slices has no effect.
s.inbound_frame(0, &[8; 7]);
check_chunks(&s, &[(0, 1), (1, 6)]);
let mut buf = [0; 16];
assert_eq!(s.read(&mut buf[..]), 7);
assert_eq!(buf[..7], [7, 6, 6, 6, 6, 6, 6]);
}
#[test]
fn stream_rx_dedupe_new_tail() {
let mut s = RxStreamOrderer::new();
s.inbound_frame(1, &[6; 6]);
check_chunks(&s, &[(1, 6)]);
// Insertion before an existing chunk causes truncation of the new chunk.
s.inbound_frame(0, &[7; 6]);
check_chunks(&s, &[(0, 1), (1, 6)]);
// New data at the end causes the tail to be added to the first chunk,
// replacing later chunks entirely.
s.inbound_frame(0, &[9; 8]);
check_chunks(&s, &[(0, 8)]);
let mut buf = [0; 16];
assert_eq!(s.read(&mut buf[..]), 8);
assert_eq!(buf[..8], [7, 9, 9, 9, 9, 9, 9, 9]);
}
#[test]
fn stream_rx_dedupe_replace() {
let mut s = RxStreamOrderer::new();
s.inbound_frame(2, &[6; 6]);
check_chunks(&s, &[(2, 6)]);
// Insertion before an existing chunk causes truncation of the new chunk.
s.inbound_frame(1, &[7; 6]);
check_chunks(&s, &[(1, 1), (2, 6)]);
// New data at the start and end replaces all the slices.
s.inbound_frame(0, &[9; 10]);
check_chunks(&s, &[(0, 10)]);
let mut buf = [0; 16];
assert_eq!(s.read(&mut buf[..]), 10);
assert_eq!(buf[..10], [9; 10]);
}
#[test]
fn trim_retired() {
let mut s = RxStreamOrderer::new();
let mut buf = [0; 18];
s.inbound_frame(0, &[1; 10]);
// Partially read slices are retained.
assert_eq!(s.read(&mut buf[..6]), 6);
check_chunks(&s, &[(0, 10)]);
// Partially read slices are kept and so are added to.
s.inbound_frame(3, &buf[..10]);
check_chunks(&s, &[(0, 13)]);
// Wholly read pieces are dropped.
assert_eq!(s.read(&mut buf[..]), 7);
assert!(s.data_ranges.is_empty());
// New data that overlaps with retired data is trimmed.
s.inbound_frame(0, &buf[..]);
check_chunks(&s, &[(13, 5)]);
}
#[test]
fn stream_flowc_update() {
let mut s = create_stream(1024 * RX_STREAM_DATA_WINDOW);
let mut buf = vec![0u8; RECV_BUFFER_SIZE + 100]; // Make it overlarge
assert!(!s.has_frames_to_write());
let big_buf = vec![0; RECV_BUFFER_SIZE];
s.inbound_stream_frame(false, 0, &big_buf).unwrap();
assert!(!s.has_frames_to_write());
assert_eq!(s.read(&mut buf).unwrap(), (RECV_BUFFER_SIZE, false));
assert!(!s.data_ready());
// flow msg generated!
assert!(s.has_frames_to_write());
// consume it
let mut builder = PacketBuilder::short(Encoder::new(), false, None::<&[u8]>);
let mut token = Vec::new();
s.write_frame(&mut builder, &mut token, &mut FrameStats::default());
// it should be gone
assert!(!s.has_frames_to_write());
}
fn create_stream(session_fc: u64) -> RecvStream {
let conn_events = ConnectionEvents::default();
RecvStream::new(
StreamId::from(67),
RX_STREAM_DATA_WINDOW,
Rc::new(RefCell::new(ReceiverFlowControl::new((), session_fc))),
conn_events,
)
}
#[test]
fn stream_max_stream_data() {
let mut s = create_stream(1024 * RX_STREAM_DATA_WINDOW);
assert!(!s.has_frames_to_write());
let big_buf = vec![0; RECV_BUFFER_SIZE];
s.inbound_stream_frame(false, 0, &big_buf).unwrap();
s.inbound_stream_frame(false, RX_STREAM_DATA_WINDOW, &[1; 1])
.unwrap_err();
}
#[test]
fn stream_orderer_bytes_ready() {
let mut rx_ord = RxStreamOrderer::new();
rx_ord.inbound_frame(0, &[1; 6]);
assert_eq!(rx_ord.bytes_ready(), 6);
assert_eq!(rx_ord.buffered(), 6);
assert_eq!(rx_ord.retired(), 0);
// read some so there's an offset into the first frame
let mut buf = [0u8; 10];
rx_ord.read(&mut buf[..2]);
assert_eq!(rx_ord.bytes_ready(), 4);
assert_eq!(rx_ord.buffered(), 4);
assert_eq!(rx_ord.retired(), 2);
// an overlapping frame
rx_ord.inbound_frame(5, &[2; 6]);
assert_eq!(rx_ord.bytes_ready(), 9);
assert_eq!(rx_ord.buffered(), 9);
assert_eq!(rx_ord.retired(), 2);
// a noncontig frame
rx_ord.inbound_frame(20, &[3; 6]);
assert_eq!(rx_ord.bytes_ready(), 9);
assert_eq!(rx_ord.buffered(), 15);
assert_eq!(rx_ord.retired(), 2);
// an old frame
rx_ord.inbound_frame(0, &[4; 2]);
assert_eq!(rx_ord.bytes_ready(), 9);
assert_eq!(rx_ord.buffered(), 15);
assert_eq!(rx_ord.retired(), 2);
}
#[test]
fn no_stream_flowc_event_after_exiting_recv() {
let mut s = create_stream(1024 * RX_STREAM_DATA_WINDOW);
let mut buf = vec![0; RECV_BUFFER_SIZE];
// Write from buf at first.
s.inbound_stream_frame(false, 0, &buf).unwrap();
// Then read into it.
s.read(&mut buf).unwrap();
assert!(s.has_frames_to_write());
s.inbound_stream_frame(true, RX_STREAM_DATA_WINDOW, &[])
.unwrap();
assert!(!s.has_frames_to_write());
}
fn create_stream_with_fc(
session_fc: Rc<RefCell<ReceiverFlowControl<()>>>,
fc_limit: u64,
) -> RecvStream {
RecvStream::new(
StreamId::from(567),
fc_limit,
session_fc,
ConnectionEvents::default(),
)
}
fn create_stream_session_flow_control() -> (RecvStream, Rc<RefCell<ReceiverFlowControl<()>>>) {
assert!(RX_STREAM_DATA_WINDOW > u64::try_from(SESSION_WINDOW).unwrap());
let session_fc = Rc::new(RefCell::new(ReceiverFlowControl::new(
(),
u64::try_from(SESSION_WINDOW).unwrap(),
)));
(
create_stream_with_fc(Rc::clone(&session_fc), RX_STREAM_DATA_WINDOW),
session_fc,
)
}
#[test]
fn session_flow_control() {
let (mut s, session_fc) = create_stream_session_flow_control();
s.inbound_stream_frame(false, 0, &[0; SESSION_WINDOW])
.unwrap();
assert!(!session_fc.borrow().frame_needed());
// The buffer is big enough to hold SESSION_WINDOW, this will make sure that we always
// read everything from he stream.
let mut buf = [0; 2 * SESSION_WINDOW];
s.read(&mut buf).unwrap();
assert!(session_fc.borrow().frame_needed());
// consume it
let mut builder = PacketBuilder::short(Encoder::new(), false, None::<&[u8]>);
let mut token = Vec::new();
session_fc
.borrow_mut()
.write_frames(&mut builder, &mut token, &mut FrameStats::default());
// Switch to SizeKnown state
s.inbound_stream_frame(true, 2 * u64::try_from(SESSION_WINDOW).unwrap() - 1, &[0])
.unwrap();
assert!(!session_fc.borrow().frame_needed());
// Receive new data that can be read.
s.inbound_stream_frame(
false,
u64::try_from(SESSION_WINDOW).unwrap(),
&[0; SESSION_WINDOW / 2 + 1],
)
.unwrap();
assert!(!session_fc.borrow().frame_needed());
s.read(&mut buf).unwrap();
assert!(session_fc.borrow().frame_needed());
// consume it
let mut builder = PacketBuilder::short(Encoder::new(), false, None::<&[u8]>);
let mut token = Vec::new();
session_fc
.borrow_mut()
.write_frames(&mut builder, &mut token, &mut FrameStats::default());
// Test DataRecvd state
let session_fc = Rc::new(RefCell::new(ReceiverFlowControl::new(
(),
u64::try_from(SESSION_WINDOW).unwrap(),
)));
let mut s = RecvStream::new(
StreamId::from(567),
RX_STREAM_DATA_WINDOW,
Rc::clone(&session_fc),
ConnectionEvents::default(),
);
s.inbound_stream_frame(true, 0, &[0; SESSION_WINDOW])
.unwrap();
assert!(!session_fc.borrow().frame_needed());
s.read(&mut buf).unwrap();
assert!(session_fc.borrow().frame_needed());
}
#[test]
fn session_flow_control_reset() {
let (mut s, session_fc) = create_stream_session_flow_control();
s.inbound_stream_frame(false, 0, &[0; SESSION_WINDOW / 2])
.unwrap();
assert!(!session_fc.borrow().frame_needed());
s.reset(
Error::NoError.code(),
u64::try_from(SESSION_WINDOW).unwrap(),
)
.unwrap();
assert!(session_fc.borrow().frame_needed());
}
fn check_fc<T: std::fmt::Debug>(fc: &ReceiverFlowControl<T>, consumed: u64, retired: u64) {
assert_eq!(fc.consumed(), consumed);
assert_eq!(fc.retired(), retired);
}
/// Test consuming the flow control in `RecvStreamState::Recv`
#[test]
fn fc_state_recv_1() {
const SW: u64 = 1024;
const SW_US: usize = 1024;
let fc = Rc::new(RefCell::new(ReceiverFlowControl::new((), SW)));
let mut s = create_stream_with_fc(Rc::clone(&fc), SW * 3 / 4);
check_fc(&fc.borrow(), 0, 0);
check_fc(s.fc().unwrap(), 0, 0);
s.inbound_stream_frame(false, 0, &[0; SW_US / 4]).unwrap();
check_fc(&fc.borrow(), SW / 4, 0);
check_fc(s.fc().unwrap(), SW / 4, 0);
}
/// Test consuming the flow control in `RecvStreamState::Recv`
/// with multiple streams
#[test]
fn fc_state_recv_2() {
const SW: u64 = 1024;
const SW_US: usize = 1024;
let fc = Rc::new(RefCell::new(ReceiverFlowControl::new((), SW)));
let mut s1 = create_stream_with_fc(Rc::clone(&fc), SW * 3 / 4);
let mut s2 = create_stream_with_fc(Rc::clone(&fc), SW * 3 / 4);
check_fc(&fc.borrow(), 0, 0);
check_fc(s1.fc().unwrap(), 0, 0);
check_fc(s2.fc().unwrap(), 0, 0);
s1.inbound_stream_frame(false, 0, &[0; SW_US / 4]).unwrap();
check_fc(&fc.borrow(), SW / 4, 0);
check_fc(s1.fc().unwrap(), SW / 4, 0);
check_fc(s2.fc().unwrap(), 0, 0);
s2.inbound_stream_frame(false, 0, &[0; SW_US / 4]).unwrap();
check_fc(&fc.borrow(), SW / 2, 0);
check_fc(s1.fc().unwrap(), SW / 4, 0);
check_fc(s2.fc().unwrap(), SW / 4, 0);
}
/// Test retiring the flow control in `RecvStreamState::Recv`
/// with multiple streams
#[test]
fn fc_state_recv_3() {
const SW: u64 = 1024;
const SW_US: usize = 1024;
let fc = Rc::new(RefCell::new(ReceiverFlowControl::new((), SW)));
let mut s1 = create_stream_with_fc(Rc::clone(&fc), SW * 3 / 4);
let mut s2 = create_stream_with_fc(Rc::clone(&fc), SW * 3 / 4);
check_fc(&fc.borrow(), 0, 0);
check_fc(s1.fc().unwrap(), 0, 0);
check_fc(s2.fc().unwrap(), 0, 0);
s1.inbound_stream_frame(false, 0, &[0; SW_US / 4]).unwrap();
s2.inbound_stream_frame(false, 0, &[0; SW_US / 4]).unwrap();
check_fc(&fc.borrow(), SW / 2, 0);
check_fc(s1.fc().unwrap(), SW / 4, 0);
check_fc(s2.fc().unwrap(), SW / 4, 0);
// Read data
let mut buf = [1; SW_US];
assert_eq!(s1.read(&mut buf).unwrap(), (SW_US / 4, false));
check_fc(&fc.borrow(), SW / 2, SW / 4);
check_fc(s1.fc().unwrap(), SW / 4, SW / 4);
check_fc(s2.fc().unwrap(), SW / 4, 0);
assert_eq!(s2.read(&mut buf).unwrap(), (SW_US / 4, false));
check_fc(&fc.borrow(), SW / 2, SW / 2);
check_fc(s1.fc().unwrap(), SW / 4, SW / 4);
check_fc(s2.fc().unwrap(), SW / 4, SW / 4);
// Read when there is no more date to be read will not change fc.
assert_eq!(s1.read(&mut buf).unwrap(), (0, false));
check_fc(&fc.borrow(), SW / 2, SW / 2);
check_fc(s1.fc().unwrap(), SW / 4, SW / 4);
check_fc(s2.fc().unwrap(), SW / 4, SW / 4);
// Receiving more data on a stream.
s1.inbound_stream_frame(false, SW / 4, &[0; SW_US / 4])
.unwrap();
check_fc(&fc.borrow(), SW * 3 / 4, SW / 2);
check_fc(s1.fc().unwrap(), SW / 2, SW / 4);
check_fc(s2.fc().unwrap(), SW / 4, SW / 4);
// Read data
assert_eq!(s1.read(&mut buf).unwrap(), (SW_US / 4, false));
check_fc(&fc.borrow(), SW * 3 / 4, SW * 3 / 4);
check_fc(s1.fc().unwrap(), SW / 2, SW / 2);
check_fc(s2.fc().unwrap(), SW / 4, SW / 4);
}
/// Test consuming the flow control in `RecvStreamState::Recv` - duplicate data
#[test]
fn fc_state_recv_4() {
const SW: u64 = 1024;
const SW_US: usize = 1024;
let fc = Rc::new(RefCell::new(ReceiverFlowControl::new((), SW)));
let mut s = create_stream_with_fc(Rc::clone(&fc), SW * 3 / 4);
check_fc(&fc.borrow(), 0, 0);
check_fc(s.fc().unwrap(), 0, 0);
s.inbound_stream_frame(false, 0, &[0; SW_US / 4]).unwrap();
check_fc(&fc.borrow(), SW / 4, 0);
check_fc(s.fc().unwrap(), SW / 4, 0);
// Receiving duplicate frames (already consumed data) will not cause an error or
// change fc.
s.inbound_stream_frame(false, 0, &[0; SW_US / 8]).unwrap();
check_fc(&fc.borrow(), SW / 4, 0);
check_fc(s.fc().unwrap(), SW / 4, 0);
}
/// Test consuming the flow control in `RecvStreamState::Recv` - filling a gap in the
/// data stream.
#[test]
fn fc_state_recv_5() {
const SW: u64 = 1024;
const SW_US: usize = 1024;
let fc = Rc::new(RefCell::new(ReceiverFlowControl::new((), SW)));
let mut s = create_stream_with_fc(Rc::clone(&fc), SW * 3 / 4);
// Receive out of order data.
s.inbound_stream_frame(false, SW / 8, &[0; SW_US / 8])
.unwrap();
check_fc(&fc.borrow(), SW / 4, 0);
check_fc(s.fc().unwrap(), SW / 4, 0);
// Filling in the gap will not change fc.
s.inbound_stream_frame(false, 0, &[0; SW_US / 8]).unwrap();
check_fc(&fc.borrow(), SW / 4, 0);
check_fc(s.fc().unwrap(), SW / 4, 0);
}
/// Test consuming the flow control in `RecvStreamState::Recv` - receiving frame past
/// the flow control will cause an error.
#[test]
fn fc_state_recv_6() {
const SW: u64 = 1024;
const SW_US: usize = 1024;
let fc = Rc::new(RefCell::new(ReceiverFlowControl::new((), SW)));
let mut s = create_stream_with_fc(Rc::clone(&fc), SW * 3 / 4);
// Receiving frame past the flow control will cause an error.
assert_eq!(
s.inbound_stream_frame(false, 0, &[0; SW_US * 3 / 4 + 1]),
Err(Error::FlowControlError)
);
}
/// Test that the flow controls will send updates.
#[test]
fn fc_state_recv_7() {
const SW: u64 = 1024;
const SW_US: usize = 1024;
let fc = Rc::new(RefCell::new(ReceiverFlowControl::new((), SW)));
let mut s = create_stream_with_fc(Rc::clone(&fc), SW / 2);
check_fc(&fc.borrow(), 0, 0);
check_fc(s.fc().unwrap(), 0, 0);
s.inbound_stream_frame(false, 0, &[0; SW_US / 4]).unwrap();
let mut buf = [1; SW_US];
assert_eq!(s.read(&mut buf).unwrap(), (SW_US / 4, false));
check_fc(&fc.borrow(), SW / 4, SW / 4);
check_fc(s.fc().unwrap(), SW / 4, SW / 4);
// Still no fc update needed.
assert!(!fc.borrow().frame_needed());
assert!(!s.fc().unwrap().frame_needed());
// Receive one more byte that will cause a fc update after it is read.
s.inbound_stream_frame(false, SW / 4, &[0]).unwrap();
check_fc(&fc.borrow(), SW / 4 + 1, SW / 4);
check_fc(s.fc().unwrap(), SW / 4 + 1, SW / 4);
// Only consuming data does not cause a fc update to be sent.
assert!(!fc.borrow().frame_needed());
assert!(!s.fc().unwrap().frame_needed());
assert_eq!(s.read(&mut buf).unwrap(), (1, false));
check_fc(&fc.borrow(), SW / 4 + 1, SW / 4 + 1);
check_fc(s.fc().unwrap(), SW / 4 + 1, SW / 4 + 1);
// Data are retired and the sttream fc will send an update.
assert!(!fc.borrow().frame_needed());
assert!(s.fc().unwrap().frame_needed());
// Receive more data to increase fc further.
s.inbound_stream_frame(false, SW / 4, &[0; SW_US / 4])
.unwrap();
assert_eq!(s.read(&mut buf).unwrap(), (SW_US / 4 - 1, false));
check_fc(&fc.borrow(), SW / 2, SW / 2);
check_fc(s.fc().unwrap(), SW / 2, SW / 2);
assert!(!fc.borrow().frame_needed());
assert!(s.fc().unwrap().frame_needed());
// Write the fc update frame
let mut builder = PacketBuilder::short(Encoder::new(), false, None::<&[u8]>);
let mut token = Vec::new();
let mut stats = FrameStats::default();
fc.borrow_mut()
.write_frames(&mut builder, &mut token, &mut stats);
assert_eq!(stats.max_data, 0);
s.write_frame(&mut builder, &mut token, &mut stats);
assert_eq!(stats.max_stream_data, 1);
// Receive 1 byte that will case a session fc update after it is read.
s.inbound_stream_frame(false, SW / 2, &[0]).unwrap();
assert_eq!(s.read(&mut buf).unwrap(), (1, false));
check_fc(&fc.borrow(), SW / 2 + 1, SW / 2 + 1);
check_fc(s.fc().unwrap(), SW / 2 + 1, SW / 2 + 1);
assert!(fc.borrow().frame_needed());
assert!(!s.fc().unwrap().frame_needed());
fc.borrow_mut()
.write_frames(&mut builder, &mut token, &mut stats);
assert_eq!(stats.max_data, 1);
s.write_frame(&mut builder, &mut token, &mut stats);
assert_eq!(stats.max_stream_data, 1);
}
/// Test flow control in `RecvStreamState::SizeKnown`
#[test]
fn fc_state_size_known() {
const SW: u64 = 1024;
const SW_US: usize = 1024;
let fc = Rc::new(RefCell::new(ReceiverFlowControl::new((), SW)));
let mut s = create_stream_with_fc(Rc::clone(&fc), SW);
check_fc(&fc.borrow(), 0, 0);
check_fc(s.fc().unwrap(), 0, 0);
s.inbound_stream_frame(true, SW / 4, &[0; SW_US / 4])
.unwrap();
check_fc(&fc.borrow(), SW / 2, 0);
check_fc(s.fc().unwrap(), SW / 2, 0);
// Receiving duplicate frames (already consumed data) will not cause an error or
// change fc.
s.inbound_stream_frame(true, SW / 4, &[0; SW_US / 4])
.unwrap();
check_fc(&fc.borrow(), SW / 2, 0);
check_fc(s.fc().unwrap(), SW / 2, 0);
// The stream can still receive duplicate data without a fin bit.
s.inbound_stream_frame(false, SW / 4, &[0; SW_US / 4])
.unwrap();
check_fc(&fc.borrow(), SW / 2, 0);
check_fc(s.fc().unwrap(), SW / 2, 0);
// Receiving frame past the final size of a stream will return an error.
assert_eq!(
s.inbound_stream_frame(true, SW / 4, &[0; SW_US / 4 + 1]),
Err(Error::FinalSizeError)
);
check_fc(&fc.borrow(), SW / 2, 0);
check_fc(s.fc().unwrap(), SW / 2, 0);
// Add new data to the gap will not change fc.
s.inbound_stream_frame(false, SW / 8, &[0; SW_US / 8])
.unwrap();
check_fc(&fc.borrow(), SW / 2, 0);
check_fc(s.fc().unwrap(), SW / 2, 0);
// Fill the gap
s.inbound_stream_frame(false, 0, &[0; SW_US / 8]).unwrap();
check_fc(&fc.borrow(), SW / 2, 0);
check_fc(s.fc().unwrap(), SW / 2, 0);
// Read all data
let mut buf = [1; SW_US];
assert_eq!(s.read(&mut buf).unwrap(), (SW_US / 2, true));
// the stream does not have fc any more. We can only check the session fc.
check_fc(&fc.borrow(), SW / 2, SW / 2);
assert!(s.fc().is_none());
}
/// Test flow control in `RecvStreamState::DataRecvd`
#[test]
fn fc_state_data_recv() {
const SW: u64 = 1024;
const SW_US: usize = 1024;
let fc = Rc::new(RefCell::new(ReceiverFlowControl::new((), SW)));
let mut s = create_stream_with_fc(Rc::clone(&fc), SW);
check_fc(&fc.borrow(), 0, 0);
check_fc(s.fc().unwrap(), 0, 0);
s.inbound_stream_frame(true, 0, &[0; SW_US / 2]).unwrap();
check_fc(&fc.borrow(), SW / 2, 0);
check_fc(s.fc().unwrap(), SW / 2, 0);
// Receiving duplicate frames (already consumed data) will not cause an error or
// change fc.
s.inbound_stream_frame(true, SW / 4, &[0; SW_US / 4])
.unwrap();
check_fc(&fc.borrow(), SW / 2, 0);
check_fc(s.fc().unwrap(), SW / 2, 0);
// The stream can still receive duplicate data without a fin bit.
s.inbound_stream_frame(false, SW / 4, &[0; SW_US / 4])
.unwrap();
check_fc(&fc.borrow(), SW / 2, 0);
check_fc(s.fc().unwrap(), SW / 2, 0);
// Receiving frame past the final size of a stream will return an error.
assert_eq!(
s.inbound_stream_frame(true, SW / 4, &[0; SW_US / 4 + 1]),
Err(Error::FinalSizeError)
);
check_fc(&fc.borrow(), SW / 2, 0);
check_fc(s.fc().unwrap(), SW / 2, 0);
// Read all data
let mut buf = [1; SW_US];
assert_eq!(s.read(&mut buf).unwrap(), (SW_US / 2, true));
// the stream does not have fc any more. We can only check the session fc.
check_fc(&fc.borrow(), SW / 2, SW / 2);
assert!(s.fc().is_none());
}
/// Test flow control in `RecvStreamState::DataRead`
#[test]
fn fc_state_data_read() {
const SW: u64 = 1024;
const SW_US: usize = 1024;
let fc = Rc::new(RefCell::new(ReceiverFlowControl::new((), SW)));
let mut s = create_stream_with_fc(Rc::clone(&fc), SW * 3 / 4);
check_fc(&fc.borrow(), 0, 0);
check_fc(s.fc().unwrap(), 0, 0);
s.inbound_stream_frame(true, 0, &[0; SW_US / 2]).unwrap();
check_fc(&fc.borrow(), SW / 2, 0);
check_fc(s.fc().unwrap(), SW / 2, 0);
let mut buf = [1; SW_US];
assert_eq!(s.read(&mut buf).unwrap(), (SW_US / 2, true));
// the stream does not have fc any more. We can only check the session fc.
check_fc(&fc.borrow(), SW / 2, SW / 2);
assert!(s.fc().is_none());
// Receiving duplicate frames (already consumed data) will not cause an error or
// change fc.
s.inbound_stream_frame(true, 0, &[0; SW_US / 2]).unwrap();
// the stream does not have fc any more. We can only check the session fc.
check_fc(&fc.borrow(), SW / 2, SW / 2);
assert!(s.fc().is_none());
// Receiving frame past the final size of a stream or the stream's fc limit
// will NOT return an error.
s.inbound_stream_frame(true, 0, &[0; SW_US / 2 + 1])
.unwrap();
s.inbound_stream_frame(true, 0, &[0; SW_US * 3 / 4 + 1])
.unwrap();
check_fc(&fc.borrow(), SW / 2, SW / 2);
assert!(s.fc().is_none());
}
/// Test flow control in `RecvStreamState::AbortReading` and final size is known
#[test]
fn fc_state_abort_reading_1() {
const SW: u64 = 1024;
const SW_US: usize = 1024;
let fc = Rc::new(RefCell::new(ReceiverFlowControl::new((), SW)));
let mut s = create_stream_with_fc(Rc::clone(&fc), SW * 3 / 4);
check_fc(&fc.borrow(), 0, 0);
check_fc(s.fc().unwrap(), 0, 0);
s.inbound_stream_frame(true, SW / 4, &[0; SW_US / 4])
.unwrap();
check_fc(&fc.borrow(), SW / 2, 0);
check_fc(s.fc().unwrap(), SW / 2, 0);
s.stop_sending(Error::NoError.code());
// All data will de retired
check_fc(&fc.borrow(), SW / 2, SW / 2);
check_fc(s.fc().unwrap(), SW / 2, SW / 2);
// Receiving duplicate frames (already consumed data) will not cause an error or
// change fc.
s.inbound_stream_frame(true, 0, &[0; SW_US / 2]).unwrap();
check_fc(&fc.borrow(), SW / 2, SW / 2);
check_fc(s.fc().unwrap(), SW / 2, SW / 2);
// The stream can still receive duplicate data without a fin bit.
s.inbound_stream_frame(false, SW / 4, &[0; SW_US / 4])
.unwrap();
check_fc(&fc.borrow(), SW / 2, SW / 2);
check_fc(s.fc().unwrap(), SW / 2, SW / 2);
// Receiving frame past the final size of a stream will return an error.
assert_eq!(
s.inbound_stream_frame(true, SW / 4, &[0; SW_US / 4 + 1]),
Err(Error::FinalSizeError)
);
check_fc(&fc.borrow(), SW / 2, SW / 2);
check_fc(s.fc().unwrap(), SW / 2, SW / 2);
}
/// Test flow control in `RecvStreamState::AbortReading` and final size is unknown
#[test]
fn fc_state_abort_reading_2() {
const SW: u64 = 1024;
const SW_US: usize = 1024;
let fc = Rc::new(RefCell::new(ReceiverFlowControl::new((), SW)));
let mut s = create_stream_with_fc(Rc::clone(&fc), SW * 3 / 4);
check_fc(&fc.borrow(), 0, 0);
check_fc(s.fc().unwrap(), 0, 0);
s.inbound_stream_frame(false, 0, &[0; SW_US / 2]).unwrap();
check_fc(&fc.borrow(), SW / 2, 0);
check_fc(s.fc().unwrap(), SW / 2, 0);
s.stop_sending(Error::NoError.code());
// All data will de retired
check_fc(&fc.borrow(), SW / 2, SW / 2);
check_fc(s.fc().unwrap(), SW / 2, SW / 2);
// Receiving duplicate frames (already consumed data) will not cause an error or
// change fc.
s.inbound_stream_frame(false, 0, &[0; SW_US / 2]).unwrap();
check_fc(&fc.borrow(), SW / 2, SW / 2);
check_fc(s.fc().unwrap(), SW / 2, SW / 2);
// Receiving data past the flow control limit will cause an error.
assert_eq!(
s.inbound_stream_frame(false, 0, &[0; SW_US * 3 / 4 + 1]),
Err(Error::FlowControlError)
);
// The stream can still receive duplicate data without a fin bit.
s.inbound_stream_frame(false, SW / 4, &[0; SW_US / 4])
.unwrap();
check_fc(&fc.borrow(), SW / 2, SW / 2);
check_fc(s.fc().unwrap(), SW / 2, SW / 2);
// Receiving more data will case the data to be retired.
// The stream can still receive duplicate data without a fin bit.
s.inbound_stream_frame(false, SW / 2, &[0; 10]).unwrap();
check_fc(&fc.borrow(), SW / 2 + 10, SW / 2 + 10);
check_fc(s.fc().unwrap(), SW / 2 + 10, SW / 2 + 10);
// We can still receive the final size.
s.inbound_stream_frame(true, SW / 2, &[0; 20]).unwrap();
check_fc(&fc.borrow(), SW / 2 + 20, SW / 2 + 20);
check_fc(s.fc().unwrap(), SW / 2 + 20, SW / 2 + 20);
// Receiving frame past the final size of a stream will return an error.
assert_eq!(
s.inbound_stream_frame(true, SW / 2, &[0; 21]),
Err(Error::FinalSizeError)
);
check_fc(&fc.borrow(), SW / 2 + 20, SW / 2 + 20);
check_fc(s.fc().unwrap(), SW / 2 + 20, SW / 2 + 20);
}
/// Test flow control in `RecvStreamState::WaitForReset`
#[test]
fn fc_state_wait_for_reset() {
const SW: u64 = 1024;
const SW_US: usize = 1024;
let fc = Rc::new(RefCell::new(ReceiverFlowControl::new((), SW)));
let mut s = create_stream_with_fc(Rc::clone(&fc), SW * 3 / 4);
check_fc(&fc.borrow(), 0, 0);
check_fc(s.fc().unwrap(), 0, 0);
s.inbound_stream_frame(false, 0, &[0; SW_US / 2]).unwrap();
check_fc(&fc.borrow(), SW / 2, 0);
check_fc(s.fc().unwrap(), SW / 2, 0);
s.stop_sending(Error::NoError.code());
check_fc(&fc.borrow(), SW / 2, SW / 2);
check_fc(s.fc().unwrap(), SW / 2, SW / 2);
s.stop_sending_acked();
check_fc(&fc.borrow(), SW / 2, SW / 2);
check_fc(s.fc().unwrap(), SW / 2, SW / 2);
// Receiving duplicate frames (already consumed data) will not cause an error or
// change fc.
s.inbound_stream_frame(false, 0, &[0; SW_US / 2]).unwrap();
check_fc(&fc.borrow(), SW / 2, SW / 2);
check_fc(s.fc().unwrap(), SW / 2, SW / 2);
// Receiving data past the flow control limit will cause an error.
assert_eq!(
s.inbound_stream_frame(false, 0, &[0; SW_US * 3 / 4 + 1]),
Err(Error::FlowControlError)
);
// The stream can still receive duplicate data without a fin bit.
s.inbound_stream_frame(false, SW / 4, &[0; SW_US / 4])
.unwrap();
check_fc(&fc.borrow(), SW / 2, SW / 2);
check_fc(s.fc().unwrap(), SW / 2, SW / 2);
// Receiving more data will case the data to be retired.
// The stream can still receive duplicate data without a fin bit.
s.inbound_stream_frame(false, SW / 2, &[0; 10]).unwrap();
check_fc(&fc.borrow(), SW / 2 + 10, SW / 2 + 10);
check_fc(s.fc().unwrap(), SW / 2 + 10, SW / 2 + 10);
}
}