2 files changed, 443 insertions, 0 deletions

diff --git a/embassy-net-ppp/src/fmt.rs b/embassy-net-ppp/src/fmt.rs
new file mode 100644
index 000000000..78e583c1c
--- /dev/null
+++ b/embassy-net-ppp/src/fmt.rs
@@ -0,0 +1,258 @@
+#![macro_use]
+#![allow(unused_macros)]
+
+use core::fmt::{Debug, Display, LowerHex};
+
+#[cfg(all(feature = "defmt", feature = "log"))]
+compile_error!("You may not enable both `defmt` and `log` features.");
+
+macro_rules! assert {
+    ($($x:tt)*) => {
+        {
+            #[cfg(not(feature = "defmt"))]
+            ::core::assert!($($x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::assert!($($x)*);
+        }
+    };
+}
+
+macro_rules! assert_eq {
+    ($($x:tt)*) => {
+        {
+            #[cfg(not(feature = "defmt"))]
+            ::core::assert_eq!($($x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::assert_eq!($($x)*);
+        }
+    };
+}
+
+macro_rules! assert_ne {
+    ($($x:tt)*) => {
+        {
+            #[cfg(not(feature = "defmt"))]
+            ::core::assert_ne!($($x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::assert_ne!($($x)*);
+        }
+    };
+}
+
+macro_rules! debug_assert {
+    ($($x:tt)*) => {
+        {
+            #[cfg(not(feature = "defmt"))]
+            ::core::debug_assert!($($x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::debug_assert!($($x)*);
+        }
+    };
+}
+
+macro_rules! debug_assert_eq {
+    ($($x:tt)*) => {
+        {
+            #[cfg(not(feature = "defmt"))]
+            ::core::debug_assert_eq!($($x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::debug_assert_eq!($($x)*);
+        }
+    };
+}
+
+macro_rules! debug_assert_ne {
+    ($($x:tt)*) => {
+        {
+            #[cfg(not(feature = "defmt"))]
+            ::core::debug_assert_ne!($($x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::debug_assert_ne!($($x)*);
+        }
+    };
+}
+
+macro_rules! todo {
+    ($($x:tt)*) => {
+        {
+            #[cfg(not(feature = "defmt"))]
+            ::core::todo!($($x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::todo!($($x)*);
+        }
+    };
+}
+
+#[cfg(not(feature = "defmt"))]
+macro_rules! unreachable {
+    ($($x:tt)*) => {
+        ::core::unreachable!($($x)*)
+    };
+}
+
+#[cfg(feature = "defmt")]
+macro_rules! unreachable {
+    ($($x:tt)*) => {
+        ::defmt::unreachable!($($x)*)
+    };
+}
+
+macro_rules! panic {
+    ($($x:tt)*) => {
+        {
+            #[cfg(not(feature = "defmt"))]
+            ::core::panic!($($x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::panic!($($x)*);
+        }
+    };
+}
+
+macro_rules! trace {
+    ($s:literal $(, $x:expr)* $(,)?) => {
+        {
+            #[cfg(feature = "log")]
+            ::log::trace!($s $(, $x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::trace!($s $(, $x)*);
+            #[cfg(not(any(feature = "log", feature="defmt")))]
+            let _ = ($( & $x ),*);
+        }
+    };
+}
+
+macro_rules! debug {
+    ($s:literal $(, $x:expr)* $(,)?) => {
+        {
+            #[cfg(feature = "log")]
+            ::log::debug!($s $(, $x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::debug!($s $(, $x)*);
+            #[cfg(not(any(feature = "log", feature="defmt")))]
+            let _ = ($( & $x ),*);
+        }
+    };
+}
+
+macro_rules! info {
+    ($s:literal $(, $x:expr)* $(,)?) => {
+        {
+            #[cfg(feature = "log")]
+            ::log::info!($s $(, $x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::info!($s $(, $x)*);
+            #[cfg(not(any(feature = "log", feature="defmt")))]
+            let _ = ($( & $x ),*);
+        }
+    };
+}
+
+macro_rules! warn {
+    ($s:literal $(, $x:expr)* $(,)?) => {
+        {
+            #[cfg(feature = "log")]
+            ::log::warn!($s $(, $x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::warn!($s $(, $x)*);
+            #[cfg(not(any(feature = "log", feature="defmt")))]
+            let _ = ($( & $x ),*);
+        }
+    };
+}
+
+macro_rules! error {
+    ($s:literal $(, $x:expr)* $(,)?) => {
+        {
+            #[cfg(feature = "log")]
+            ::log::error!($s $(, $x)*);
+            #[cfg(feature = "defmt")]
+            ::defmt::error!($s $(, $x)*);
+            #[cfg(not(any(feature = "log", feature="defmt")))]
+            let _ = ($( & $x ),*);
+        }
+    };
+}
+
+#[cfg(feature = "defmt")]
+macro_rules! unwrap {
+    ($($x:tt)*) => {
+        ::defmt::unwrap!($($x)*)
+    };
+}
+
+#[cfg(not(feature = "defmt"))]
+macro_rules! unwrap {
+    ($arg:expr) => {
+        match $crate::fmt::Try::into_result($arg) {
+            ::core::result::Result::Ok(t) => t,
+            ::core::result::Result::Err(e) => {
+                ::core::panic!("unwrap of `{}` failed: {:?}", ::core::stringify!($arg), e);
+            }
+        }
+    };
+    ($arg:expr, $($msg:expr),+ $(,)? ) => {
+        match $crate::fmt::Try::into_result($arg) {
+            ::core::result::Result::Ok(t) => t,
+            ::core::result::Result::Err(e) => {
+                ::core::panic!("unwrap of `{}` failed: {}: {:?}", ::core::stringify!($arg), ::core::format_args!($($msg,)*), e);
+            }
+        }
+    }
+}
+
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+pub struct NoneError;
+
+pub trait Try {
+    type Ok;
+    type Error;
+    fn into_result(self) -> Result<Self::Ok, Self::Error>;
+}
+
+impl<T> Try for Option<T> {
+    type Ok = T;
+    type Error = NoneError;
+
+    #[inline]
+    fn into_result(self) -> Result<T, NoneError> {
+        self.ok_or(NoneError)
+    }
+}
+
+impl<T, E> Try for Result<T, E> {
+    type Ok = T;
+    type Error = E;
+
+    #[inline]
+    fn into_result(self) -> Self {
+        self
+    }
+}
+
+#[allow(unused)]
+pub(crate) struct Bytes<'a>(pub &'a [u8]);
+
+impl<'a> Debug for Bytes<'a> {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        write!(f, "{:#02x?}", self.0)
+    }
+}
+
+impl<'a> Display for Bytes<'a> {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        write!(f, "{:#02x?}", self.0)
+    }
+}
+
+impl<'a> LowerHex for Bytes<'a> {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        write!(f, "{:#02x?}", self.0)
+    }
+}
+
+#[cfg(feature = "defmt")]
+impl<'a> defmt::Format for Bytes<'a> {
+    fn format(&self, fmt: defmt::Formatter) {
+        defmt::write!(fmt, "{:02x}", self.0)
+    }
+}
diff --git a/embassy-net-ppp/src/lib.rs b/embassy-net-ppp/src/lib.rs
new file mode 100644
index 000000000..66496ee0a
--- /dev/null
+++ b/embassy-net-ppp/src/lib.rs
@@ -0,0 +1,185 @@
+#![no_std]
+#![warn(missing_docs)]
+#![doc = include_str!("../README.md")]
+
+// must be first
+mod fmt;
+
+use core::convert::Infallible;
+use core::mem::MaybeUninit;
+
+use embassy_futures::select::{select, Either};
+use embassy_net_driver_channel as ch;
+use embassy_net_driver_channel::driver::LinkState;
+use embedded_io_async::{BufRead, Write, WriteAllError};
+use ppproto::pppos::{BufferFullError, PPPoS, PPPoSAction};
+pub use ppproto::{Config, Ipv4Status};
+
+const MTU: usize = 1500;
+
+/// Type alias for the embassy-net driver.
+pub type Device<'d> = embassy_net_driver_channel::Device<'d, MTU>;
+
+/// Internal state for the embassy-net integration.
+pub struct State<const N_RX: usize, const N_TX: usize> {
+    ch_state: ch::State<MTU, N_RX, N_TX>,
+}
+
+impl<const N_RX: usize, const N_TX: usize> State<N_RX, N_TX> {
+    /// Create a new `State`.
+    pub const fn new() -> Self {
+        Self {
+            ch_state: ch::State::new(),
+        }
+    }
+}
+
+/// Background runner for the driver.
+///
+/// You must call `.run()` in a background task for the driver to operate.
+pub struct Runner<'d> {
+    ch: ch::Runner<'d, MTU>,
+}
+
+/// Error returned by [`Runner::run`].
+#[derive(Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub enum RunError<E> {
+    /// Reading from the serial port failed.
+    Read(E),
+    /// Writing to the serial port failed.
+    Write(E),
+    /// Writing to the serial port wrote zero bytes, indicating it can't accept more data.
+    WriteZero,
+    /// Writing to the serial got EOF.
+    Eof,
+    /// PPP protocol was terminated by the peer
+    Terminated,
+}
+
+impl<E> From<WriteAllError<E>> for RunError<E> {
+    fn from(value: WriteAllError<E>) -> Self {
+        match value {
+            WriteAllError::Other(e) => Self::Write(e),
+            WriteAllError::WriteZero => Self::WriteZero,
+        }
+    }
+}
+
+impl<'d> Runner<'d> {
+    /// You must call this in a background task for the driver to operate.
+    ///
+    /// If reading/writing to the underlying serial port fails, the link state
+    /// is set to Down and the error is returned.
+    ///
+    /// It is allowed to cancel this function's future (i.e. drop it). This will terminate
+    /// the PPP connection and set the link state to Down.
+    ///
+    /// After this function returns or is canceled, you can call it again to establish
+    /// a new PPP connection.
+    pub async fn run<RW: BufRead + Write>(
+        &mut self,
+        mut rw: RW,
+        config: ppproto::Config<'_>,
+        mut on_ipv4_up: impl FnMut(Ipv4Status),
+    ) -> Result<Infallible, RunError<RW::Error>> {
+        let mut ppp = PPPoS::new(config);
+        ppp.open().unwrap();
+
+        let (state_chan, mut rx_chan, mut tx_chan) = self.ch.borrow_split();
+        state_chan.set_link_state(LinkState::Down);
+        let _ondrop = OnDrop::new(|| state_chan.set_link_state(LinkState::Down));
+
+        let mut rx_buf = [0; 2048];
+        let mut tx_buf = [0; 2048];
+
+        let mut needs_poll = true;
+        let mut was_up = false;
+
+        loop {
+            let rx_fut = async {
+                let buf = rx_chan.rx_buf().await;
+                let rx_data = match needs_poll {
+                    true => &[][..],
+                    false => match rw.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);
+                    rw.consume(n);
+
+                    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());
+                        }
+                        PPPoSAction::Transmit(n) => rw.write_all(&tx_buf[..n]).await?,
+                    }
+
+                    let status = ppp.status();
+                    match status.phase {
+                        ppproto::Phase::Dead => {
+                            return Err(RunError::Terminated);
+                        }
+                        ppproto::Phase::Open => {
+                            if !was_up {
+                                on_ipv4_up(status.ipv4.unwrap());
+                            }
+                            was_up = true;
+                            state_chan.set_link_state(LinkState::Up);
+                        }
+                        _ => {
+                            was_up = false;
+                            state_chan.set_link_state(LinkState::Down);
+                        }
+                    }
+                }
+                Either::Second(pkt) => {
+                    match ppp.send(pkt, &mut tx_buf) {
+                        Ok(n) => rw.write_all(&tx_buf[..n]).await?,
+                        Err(BufferFullError) => unreachable!(),
+                    }
+                    tx_chan.tx_done();
+                }
+            }
+        }
+    }
+}
+
+/// Create a PPP embassy-net driver instance.
+///
+/// This returns two structs:
+/// - a `Device` that you must pass to the `embassy-net` stack.
+/// - a `Runner`. You must call `.run()` on it in a background task.
+pub fn new<'a, const N_RX: usize, const N_TX: usize>(state: &'a mut State<N_RX, N_TX>) -> (Device<'a>, Runner<'a>) {
+    let (runner, device) = ch::new(&mut state.ch_state, ch::driver::HardwareAddress::Ip);
+    (device, Runner { ch: runner })
+}
+
+struct OnDrop<F: FnOnce()> {
+    f: MaybeUninit<F>,
+}
+
+impl<F: FnOnce()> OnDrop<F> {
+    fn new(f: F) -> Self {
+        Self { f: MaybeUninit::new(f) }
+    }
+}
+
+impl<F: FnOnce()> Drop for OnDrop<F> {
+    fn drop(&mut self) {
+        unsafe { self.f.as_ptr().read()() }
+    }
+}