feature: add nal support

Cargo.toml

@@ -21,6 +21,9 @@ cortex-m-rt = { version = "0.6", optional = true }
 cortex-m-rtic = { version = "0.5.3", optional = true }
 panic-itm = { version = "0.4", optional = true }
 log = { version = "0.4", optional = true }
+embedded-time = { version = "0.10.1", optional = true }
+embedded-nal = { version = "0.1.0", optional = true }
+heapless = { version = "0.5.6", optional = true }
 
 [features]
 smoltcp-phy = ["smoltcp"]
@@ -31,6 +34,7 @@ smoltcp-phy-all = [
 # Example-based features
 tx_stm32f407 = ["stm32f4xx-hal/stm32f407", "cortex-m", "cortex-m-rtic", "panic-itm", "log"]
 tcp_stm32f407 = ["stm32f4xx-hal/stm32f407", "cortex-m", "cortex-m-rt", "cortex-m-rtic", "smoltcp-phy-all", "smoltcp/log", "panic-itm", "log"]
+nal = [ "embedded-time", "embedded-nal", "smoltcp-phy", "heapless" ]
 default = []
 
 [[example]]

src/lib.rs

@@ -14,6 +14,9 @@ pub mod tx;
 #[cfg(feature="smoltcp")]
 pub mod smoltcp_phy;
 
+#[cfg(feature="nal")]
+pub mod nal;
+
 /// Max raw frame array size
 pub const RAW_FRAME_LENGTH_MAX: usize = 1518;
 

src/nal.rs

@@ -0,0 +1,245 @@
+use core::cell::RefCell;
+use core::convert::TryFrom;
+use heapless::{consts, Vec};
+use embedded_nal as nal;
+use nal::nb;
+use smoltcp as net;
+use embedded_hal::{
+    blocking::spi::Transfer,
+    digital::v2::OutputPin
+};
+pub use embedded_time as time;
+use time::duration::*;
+
+#[derive(Debug)]
+pub enum NetworkError {
+    NoSocket,
+    ConnectionFailure,
+    ReadFailure,
+    WriteFailure,
+    Unsupported,
+    TimeFault,
+}
+
+pub type NetworkInterface<SPI, NSS> = net::iface::EthernetInterface<
+    'static,
+    crate::smoltcp_phy::SmoltcpDevice<
+        crate::SpiEth<SPI, NSS, fn(u32)>
+    >,
+>;
+
+pub struct NetworkStack<'a, SPI, NSS, IntClock>
+where
+    SPI: 'static + Transfer<u8>,
+    NSS: 'static + OutputPin,
+    IntClock: time::Clock<T = u32>,
+{
+    network_interface: RefCell<NetworkInterface<SPI, NSS>>,
+    sockets: RefCell<net::socket::SocketSet<'a>>,
+    next_port: RefCell<u16>,
+    unused_handles: RefCell<Vec<net::socket::SocketHandle, consts::U16>>,
+    time_ms: RefCell<u32>,
+    last_update_instant: RefCell<Option<time::Instant<IntClock>>>,
+    clock: IntClock
+}
+
+impl<'a, SPI, NSS, IntClock> NetworkStack<'a, SPI, NSS, IntClock>
+where
+    SPI: Transfer<u8>,
+    NSS: OutputPin,
+    IntClock: time::Clock<T = u32>,
+{
+    pub fn new(interface: NetworkInterface<SPI, NSS>, sockets: net::socket::SocketSet<'a>, clock: IntClock) -> Self {
+        let mut unused_handles: Vec<net::socket::SocketHandle, consts::U16> = Vec::new();
+        for socket in sockets.iter() {
+            unused_handles.push(socket.handle()).unwrap();
+        }
+        NetworkStack {
+            network_interface: RefCell::new(interface),
+            sockets: RefCell::new(sockets),
+            next_port: RefCell::new(49152),
+            unused_handles: RefCell::new(unused_handles),
+            time_ms: RefCell::new(0),
+            last_update_instant: RefCell::new(None),
+            clock,
+        }
+    }
+
+    // Include auto_time_update to allow Instant::now() to not be called
+    // Instant::now() is not safe to call in `init()` context
+    pub fn update(&self, auto_time_update: bool) -> Result<bool, NetworkError> {
+        if auto_time_update {
+            // Check if it is the first time the stack has updated the time itself
+            let now = match *self.last_update_instant.borrow() {
+                // If it is the first time, do not advance time
+                // Simply store the current instant to initiate time updating
+                None => self.clock.try_now().map_err(|_| NetworkError::TimeFault)?,
+                // If it was updated before, advance time and update last_update_instant
+                Some(instant) => {
+                    // Calculate elapsed time
+                    let now = self.clock.try_now().map_err(|_| NetworkError::TimeFault)?;
+                    let duration = now.checked_duration_since(&instant).ok_or(NetworkError::TimeFault)?;
+                    let duration_ms = time::duration::Milliseconds::<u32>::try_from(duration).map_err(|_| NetworkError::TimeFault)?;
+                    // Adjust duration into ms (note: decimal point truncated)
+                    self.advance_time(*duration_ms.integer());
+                    now
+                }
+            };
+            self.last_update_instant.replace(Some(now));
+        }
+        match self.network_interface.borrow_mut().poll(
+            &mut self.sockets.borrow_mut(),
+            net::time::Instant::from_millis(*self.time_ms.borrow() as i64),
+        ) {
+            Ok(changed) => Ok(!changed),
+            Err(_e) => {
+                Ok(true)
+            }
+        }
+    }
+
+    pub fn advance_time(&self, duration: u32) {
+        let time = self.time_ms.try_borrow().unwrap().wrapping_add(duration);
+        self.time_ms.replace(time);
+    }
+
+    fn get_ephemeral_port(&self) -> u16 {
+        // Get the next ephemeral port
+        let current_port = self.next_port.borrow().clone();
+        let (next, wrap) = self.next_port.borrow().overflowing_add(1);
+        *self.next_port.borrow_mut() = if wrap { 49152 } else { next };
+        return current_port;
+    }
+}
+impl<'a, SPI, NSS, IntClock> nal::TcpStack for NetworkStack<'a, SPI, NSS, IntClock>
+where
+    SPI: Transfer<u8>,
+    NSS: OutputPin,
+    IntClock: time::Clock<T = u32>,
+{
+    type TcpSocket = net::socket::SocketHandle;
+    type Error = NetworkError;
+    fn open(&self, _mode: nal::Mode) -> Result<Self::TcpSocket, Self::Error> {
+        match self.unused_handles.borrow_mut().pop() {
+            Some(handle) => {
+                // Abort any active connections on the handle.
+                let mut sockets = self.sockets.borrow_mut();
+                let internal_socket: &mut net::socket::TcpSocket = &mut *sockets.get(handle);
+                internal_socket.abort();
+                Ok(handle)
+            }
+            None => Err(NetworkError::NoSocket),
+        }
+    }
+
+    // Ideally connect is only to be performed in `init()` of `main.rs`
+    // Calling `Instant::now()` of `rtic::cyccnt` would face correctness issue during `init()`
+    fn connect(
+        &self,
+        socket: Self::TcpSocket,
+        remote: nal::SocketAddr,
+    ) -> Result<Self::TcpSocket, Self::Error> {
+        let address = {
+            let mut sockets = self.sockets.borrow_mut();
+            let internal_socket: &mut net::socket::TcpSocket = &mut *sockets.get(socket);
+            // If we're already in the process of connecting, ignore the request silently.
+            if internal_socket.is_open() {
+                return Ok(socket);
+            }
+            match remote.ip() {
+                nal::IpAddr::V4(addr) => {
+                    let address =
+                        net::wire::Ipv4Address::from_bytes(&addr.octets()[..]);
+                    internal_socket
+                        .connect((address, remote.port()), self.get_ephemeral_port())
+                        .map_err(|_| NetworkError::ConnectionFailure)?;
+                    net::wire::IpAddress::Ipv4(address)
+                }
+                nal::IpAddr::V6(addr) => {
+                    let address = net::wire::Ipv6Address::from_parts(&addr.segments()[..]);
+                    internal_socket.connect((address, remote.port()), self.get_ephemeral_port())
+                        .map_err(|_| NetworkError::ConnectionFailure)?;
+                    net::wire::IpAddress::Ipv6(address)
+                }
+            }
+        };
+        // Blocking connect
+        loop {
+            match self.is_connected(&socket) {
+                Ok(true) => break,
+                _ => {
+                    let mut sockets = self.sockets.borrow_mut();
+                    let internal_socket: &mut net::socket::TcpSocket = &mut *sockets.get(socket);
+                    // If the connect got ACK->RST, it will end up in Closed TCP state
+                    // Perform reconnection in this case
+                    if internal_socket.state() == net::socket::TcpState::Closed {
+                        internal_socket.close();
+                        internal_socket
+                            .connect((address, remote.port()), self.get_ephemeral_port())
+                            .map_err(|_| NetworkError::ConnectionFailure)?;
+                    }
+                }
+            }
+            // Avoid using Instant::now() and Advance time manually
+            self.update(false)?;
+            {
+                self.advance_time(1);
+            }
+        }
+        Ok(socket)
+    }
+
+    fn is_connected(&self, socket: &Self::TcpSocket) -> Result<bool, Self::Error> {
+        let mut sockets = self.sockets.borrow_mut();
+        let socket: &mut net::socket::TcpSocket = &mut *sockets.get(*socket);
+        Ok(socket.may_send() && socket.may_recv())
+    }
+
+    fn write(&self, socket: &mut Self::TcpSocket, buffer: &[u8]) -> nb::Result<usize, Self::Error> {
+        let mut non_queued_bytes = &buffer[..];
+        while non_queued_bytes.len() != 0 {
+            let result = {
+                let mut sockets = self.sockets.borrow_mut();
+                let socket: &mut net::socket::TcpSocket = &mut *sockets.get(*socket);
+                let result = socket.send_slice(non_queued_bytes);
+                result
+            };
+            match result {
+                Ok(num_bytes) => {
+                    // In case the buffer is filled up, push bytes into ethernet driver
+                    if num_bytes != non_queued_bytes.len() {
+                        self.update(true)?;
+                    }
+                    // Process the unwritten bytes again, if any
+                    non_queued_bytes = &non_queued_bytes[num_bytes..]
+                }
+                Err(_) => return Err(nb::Error::Other(NetworkError::WriteFailure)),
+            }
+        }
+        Ok(buffer.len())
+    }
+
+    fn read(
+        &self,
+        socket: &mut Self::TcpSocket,
+        buffer: &mut [u8],
+    ) -> nb::Result<usize, Self::Error> {
+        // Enqueue received bytes into the TCP socket buffer
+        self.update(true)?;
+        let mut sockets = self.sockets.borrow_mut();
+        let socket: &mut net::socket::TcpSocket = &mut *sockets.get(*socket);
+        let result = socket.recv_slice(buffer);
+        match result {
+            Ok(num_bytes) => Ok(num_bytes),
+            Err(_) => Err(nb::Error::Other(NetworkError::ReadFailure)),
+        }
+    }
+
+    fn close(&self, socket: Self::TcpSocket) -> Result<(), Self::Error> {
+        let mut sockets = self.sockets.borrow_mut();
+        let internal_socket: &mut net::socket::TcpSocket = &mut *sockets.get(socket);
+        internal_socket.close();
+        self.unused_handles.borrow_mut().push(socket).unwrap();
+        Ok(())
+    }
+}