92 lines
3.6 KiB
Rust
92 lines
3.6 KiB
Rust
///! Network Stack Sharing Utilities
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///!
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///! # Design
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///! This module provides a mechanism for sharing a single network stack safely between drivers
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///that may or may not execute in multiple contexts. The design copies that of `shared-bus`.
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///!
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///! Specifically, the network stack is stored in a global static singleton and proxies to the
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///! underlying stack are handed out. The proxies provide an identical API for the
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///! `embedded_nal::TcpStack` stack trait, so they can be provided direclty to drivers that require
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///! a network stack.
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///!
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///! In order to ensure that pre-emption does not occur while accessing the same network stack from
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///! multiple interrupt contexts, the proxy uses an atomic boolean check - if the flag indicates the
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///! stack is in use, the proxy will generate a panic. The actual synchronization mechanism (mutex)
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///! leverages RTIC resource allocation. All devices that use the underlying network stack must be
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///! placed in a single RTIC resource, which will cause RTIC to prevent contention for the
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///! underlying network stack.
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use minimq::embedded_nal;
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use shared_bus::{AtomicCheckMutex, BusMutex};
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use crate::hardware::NetworkStack;
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/// A manager for a shared network stack.
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pub struct NetworkManager {
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mutex: AtomicCheckMutex<NetworkStack>,
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}
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/// A basic proxy that references a shared network stack.
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pub struct NetworkStackProxy<'a, S> {
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mutex: &'a AtomicCheckMutex<S>,
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}
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impl<'a, S> NetworkStackProxy<'a, S> {
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/// Using the proxy, access the underlying network stack directly.
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///
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/// # Args
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/// * `f` - A closure which will be provided the network stack as an argument.
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///
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/// # Returns
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/// Any value returned by the provided closure
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pub fn lock<R, F: FnOnce(&mut S) -> R>(&mut self, f: F) -> R {
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self.mutex.lock(|stack| f(stack))
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}
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}
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// A simple forwarding macro taken from the `embedded-nal` to forward the embedded-nal API into the
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// proxy structure.
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macro_rules! forward {
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($func:ident($($v:ident: $IT:ty),*) -> $T:ty) => {
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fn $func(&self, $($v: $IT),*) -> $T {
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self.mutex.lock(|stack| stack.$func($($v),*))
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}
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}
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}
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// Implement a TCP stack for the proxy if the underlying network stack implements it.
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impl<'a, S> embedded_nal::TcpStack for NetworkStackProxy<'a, S>
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where
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S: embedded_nal::TcpStack,
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{
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type TcpSocket = S::TcpSocket;
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type Error = S::Error;
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forward! {open(mode: embedded_nal::Mode) -> Result<S::TcpSocket, S::Error>}
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forward! {connect(socket: S::TcpSocket, remote: embedded_nal::SocketAddr) -> Result<S::TcpSocket, S::Error>}
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forward! {is_connected(socket: &S::TcpSocket) -> Result<bool, S::Error>}
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forward! {write(socket: &mut S::TcpSocket, buffer: &[u8]) -> embedded_nal::nb::Result<usize, S::Error>}
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forward! {read(socket: &mut S::TcpSocket, buffer: &mut [u8]) -> embedded_nal::nb::Result<usize, S::Error>}
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forward! {close(socket: S::TcpSocket) -> Result<(), S::Error>}
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}
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impl NetworkManager {
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/// Construct a new manager for a shared network stack
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///
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/// # Args
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/// * `stack` - The network stack that is being shared.
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pub fn new(stack: NetworkStack) -> Self {
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Self {
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mutex: AtomicCheckMutex::create(stack),
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}
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}
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/// Acquire a proxy to the shared network stack.
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///
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/// # Returns
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/// A proxy that can be used in place of the network stack. Note the requirements of
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/// concurrency listed in the description of this file for usage.
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pub fn acquire_stack(&'_ self) -> NetworkStackProxy<'_, NetworkStack> {
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NetworkStackProxy { mutex: &self.mutex }
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}
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}
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