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net-ppp: nicer processing loop structure that can't deadlock.

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This commit is contained in:
Dario Nieuwenhuis 2023-08-25 15:39:25 +02:00
parent aacf14b62a
commit 2303382dfd
1 changed files with 41 additions and 43 deletions
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84
embassy-net-ppp/src/lib.rs
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@ -8,11 +8,9 @@ mod fmt;
use core::convert::Infallible;
use core::mem::MaybeUninit;
use embassy_futures::select::{select3, Either3};
use embassy_futures::select::{select, Either};
use embassy_net_driver_channel as ch;
use embassy_net_driver_channel::driver::LinkState;
use embassy_sync::blocking_mutex::raw::NoopRawMutex;
use embassy_sync::signal::Signal;
use embedded_io_async::{BufRead, Write, WriteAllError};
use ppproto::pppos::{BufferFullError, PPPoS, PPPoSAction};
@ -75,22 +73,50 @@ impl<'d, R: BufRead, W: Write> Runner<'d, R, W> {
let mut rx_buf = [0; 2048];
let mut tx_buf = [0; 2048];
let poll_signal: Signal<NoopRawMutex, ()> = Signal::new();
poll_signal.signal(());
let mut needs_poll = true;
loop {
let mut poll = false;
match select3(self.r.fill_buf(), tx_chan.tx_buf(), poll_signal.wait()).await {
Either3::First(r) => {
let data = r.map_err(RunError::Read)?;
if data.is_empty() {
return Err(RunError::Eof);
}
let n = ppp.consume(data, &mut rx_buf);
let rx_fut = async {
let buf = rx_chan.rx_buf().await;
let rx_data = match needs_poll {
true => &[][..],
false => match self.r.fill_buf().await {
Ok(rx_data) if rx_data.len() == 0 => return Err(RunError::Eof),
Ok(rx_data) => rx_data,
Err(e) => return Err(RunError::Read(e)),
},
};
Ok((buf, rx_data))
};
let tx_fut = tx_chan.tx_buf();
match select(rx_fut, tx_fut).await {
Either::First(r) => {
needs_poll = false;
let (buf, rx_data) = r?;
let n = ppp.consume(rx_data, &mut rx_buf);
self.r.consume(n);
poll = true;
match ppp.poll(&mut tx_buf, &mut rx_buf) {
PPPoSAction::None => {}
PPPoSAction::Received(rg) => {
let pkt = &rx_buf[rg];
buf[..pkt.len()].copy_from_slice(pkt);
rx_chan.rx_done(pkt.len());
}
Either3::Second(pkt) => {
PPPoSAction::Transmit(n) => match self.w.write_all(&tx_buf[..n]).await {
Ok(()) => {}
Err(WriteAllError::WriteZero) => return Err(RunError::WriteZero),
Err(WriteAllError::Other(e)) => return Err(RunError::Write(e)),
},
}
match ppp.status().phase {
ppproto::Phase::Open => state_chan.set_link_state(LinkState::Up),
_ => state_chan.set_link_state(LinkState::Down),
}
}
Either::Second(pkt) => {
match ppp.send(pkt, &mut tx_buf) {
Ok(n) => match self.w.write_all(&tx_buf[..n]).await {
Ok(()) => {}
@ -101,34 +127,6 @@ impl<'d, R: BufRead, W: Write> Runner<'d, R, W> {
}
tx_chan.tx_done();
}
Either3::Third(_) => poll = true,
}
if poll {
match ppp.poll(&mut tx_buf, &mut rx_buf) {
PPPoSAction::None => {}
PPPoSAction::Received(rg) => {
let pkt = &rx_buf[rg];
let buf = rx_chan.rx_buf().await; // TODO: fix possible deadlock
buf[..pkt.len()].copy_from_slice(pkt);
rx_chan.rx_done(pkt.len());
poll_signal.signal(());
}
PPPoSAction::Transmit(n) => {
match self.w.write_all(&tx_buf[..n]).await {
Ok(()) => {}
Err(WriteAllError::WriteZero) => return Err(RunError::WriteZero),
Err(WriteAllError::Other(e)) => return Err(RunError::Write(e)),
}
poll_signal.signal(());
}
}
match ppp.status().phase {
ppproto::Phase::Open => state_chan.set_link_state(LinkState::Up),
_ => state_chan.set_link_state(LinkState::Down),
}
}
}
}