riot_wrappers/socket_embedded_nal_async_udp.rs
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use crate::async_helpers::{RiotStyleFuture, RiotStylePollStruct};
use crate::error::{NegativeErrorExt, NumericError, ENOSPC};
use crate::socket::UdpEp;
use core::mem::MaybeUninit;
use riot_sys::sock_udp_t;
#[derive(Debug)]
pub struct UdpStack {
// It's annoying we need those not to move; just asking the user to help us out here.
static_socket_factory: fn() -> Option<&'static mut MaybeUninit<sock_udp_t>>,
}
impl UdpStack {
pub fn new(factory: fn() -> Option<&'static mut MaybeUninit<sock_udp_t>>) -> Self {
Self {
static_socket_factory: factory,
}
}
/// Wrpper for sock_udp_create that pulls its immovable item right out of the factory
fn create(
&self,
local: Option<UdpEp>,
remote: Option<UdpEp>,
flags: u16,
) -> Result<&'static mut sock_udp_t, NumericError> {
let socket = (self.static_socket_factory)().ok_or(ENOSPC)?;
Ok(unsafe {
riot_sys::sock_udp_create(
socket.as_mut_ptr(),
local
.as_ref()
.map(|s| s.as_ref() as *const _)
.unwrap_or(core::ptr::null()),
remote
.as_ref()
.map(|s| s.as_ref() as *const _)
.unwrap_or(core::ptr::null()),
flags,
)
.negative_to_error()?;
socket.assume_init_mut()
})
}
}
fn get_local(socket: &mut sock_udp_t) -> Result<UdpEp, NumericError> {
let mut final_local = MaybeUninit::uninit();
Ok(unsafe {
riot_sys::sock_udp_get_local(socket, final_local.as_mut_ptr()).negative_to_error()?;
final_local.assume_init()
}
.into())
}
impl embedded_io_async::Error for NumericError {
fn kind(&self) -> embedded_io_async::ErrorKind {
// FIXME there are some that do make sense here
embedded_io_async::ErrorKind::Other
}
}
#[derive(Debug)]
pub struct ConnectedUdpSocket {
socket: &'static mut sock_udp_t,
}
impl Drop for ConnectedUdpSocket {
fn drop(&mut self) {
unsafe { riot_sys::sock_udp_close(self.socket) };
}
}
#[derive(Debug)]
pub struct UnconnectedUdpSocket {
socket: &'static mut sock_udp_t,
}
macro_rules! implementation_module {
($ena_crate:ident) => {
use super::*;
impl $ena_crate::UdpStack for UdpStack {
type Error = NumericError;
type Connected = ConnectedUdpSocket;
// This could be done more efficiently (in particular, the send of UniquelyBound wouldn't need
// to use aux to get the sender address in), but right now implementer efficiency is the
// bottleneck.
type UniquelyBound = UnconnectedUdpSocket;
type MultiplyBound = UnconnectedUdpSocket;
async fn connect_from(
&self,
local: $ena_crate::SocketAddr,
remote: $ena_crate::SocketAddr,
) -> Result<($ena_crate::SocketAddr, Self::Connected), Self::Error> {
let mut socket = self.create(Some(local.into()), Some(remote.into()), 0)?;
let final_local = get_local(&mut socket)?;
// FIXME: Verify that sock really narrows local address in case something unspecified was
// passed in
// (first tests indicate that while the UDP port is fixed, the local address is not)
Ok((final_local.into(), ConnectedUdpSocket { socket }))
}
async fn bind_single(
&self,
local: $ena_crate::SocketAddr,
) -> Result<($ena_crate::SocketAddr, Self::UniquelyBound), Self::Error> {
let mut socket = self.create(Some(local.into()), None, 0)?;
let final_local = get_local(&mut socket)?;
Ok((final_local.into(), UnconnectedUdpSocket { socket }))
}
async fn bind_multiple(
&self,
local: $ena_crate::SocketAddr,
) -> Result<Self::MultiplyBound, Self::Error> {
let socket = self.create(Some(local.into()), None, 0)?;
Ok(UnconnectedUdpSocket { socket })
}
}
impl $ena_crate::ConnectedUdp for ConnectedUdpSocket {
type Error = NumericError;
async fn send(&mut self, data: &[u8]) -> Result<(), Self::Error> {
unsafe {
riot_sys::sock_udp_send(
crate::inline_cast_ref_mut(self.socket),
data.as_ptr() as _,
data.len() as _,
core::ptr::null(),
)
.negative_to_error()?
};
Ok(())
}
async fn receive_into(&mut self, buffer: &mut [u8]) -> Result<usize, Self::Error> {
// This could be done more efficiently by ugins a ReceiveIntoArgs variant that doesn't pull
// out a remote through a pointer and a local through an aux, but as long our bottleneck is
// implementer efficiency, dropping that data is fine.
RiotStylePollStruct::new(ReceiveIntoArgs {
sock: self.socket,
buffer,
})
.await
.map(|(n, _local, _remote)| n)
}
}
impl $ena_crate::UnconnectedUdp for UnconnectedUdpSocket {
type Error = NumericError;
async fn send(
&mut self,
local: $ena_crate::SocketAddr,
remote: $ena_crate::SocketAddr,
data: &[u8],
) -> Result<(), Self::Error> {
let remote: UdpEp = remote.into();
let local: UdpEp = local.into();
let mut aux = riot_sys::sock_udp_aux_tx_t {
local: local.0,
flags: riot_sys::SOCK_AUX_SET_LOCAL as _,
..Default::default()
};
unsafe {
riot_sys::inline::sock_udp_send_aux(
crate::inline_cast_ref_mut(self.socket),
data.as_ptr() as _,
data.len() as _,
remote.as_ref() as *const _,
crate::inline_cast_ref_mut(&mut aux),
)
.negative_to_error()?
};
Ok(())
}
async fn receive_into(
&mut self,
buffer: &mut [u8],
) -> Result<
(
usize,
$ena_crate::SocketAddr,
$ena_crate::SocketAddr,
),
Self::Error,
> {
RiotStylePollStruct::new(ReceiveIntoArgs {
sock: self.socket,
buffer,
})
.await
}
}
struct ReceiveIntoArgs<'a> {
sock: &'a mut sock_udp_t,
buffer: &'a mut [u8],
}
impl RiotStyleFuture for ReceiveIntoArgs<'_> {
type Output = Result<
(
usize,
$ena_crate::SocketAddr,
$ena_crate::SocketAddr,
),
NumericError,
>;
fn poll(&mut self, arg: *mut riot_sys::libc::c_void) -> core::task::Poll<Self::Output> {
let sock: &mut sock_udp_t = self.sock;
// Using recv_buf so that we can get the full length, and thus deliver the first
// slice without misleading the receiver about the length of the datagram.
//
// Effectively, this is the sock_udp_recv function (which is internally
// sock_udp_recv_buf with consecutive memcpy calls) reimplemented in Rust, but with
// the change that it counts up to the full datagram length
let mut data = core::ptr::null_mut();
let mut buf_ctx = core::ptr::null_mut();
let mut cursor = 0;
// It'd be nice if we could leave that uninitialized...
let mut aux = riot_sys::sock_udp_aux_rx_t {
flags: riot_sys::SOCK_AUX_GET_LOCAL as _,
..Default::default()
};
let mut remote = MaybeUninit::uninit();
let mut auxptr = Some(&mut aux);
let mut remoteptr = Some(&mut remote);
loop {
match (unsafe {
riot_sys::sock_udp_recv_buf_aux(
sock,
&mut data,
&mut buf_ctx,
// Return immediately
0,
// That's a mouthful for "pass this pointer, and zero the pointer after the
// first time" (because we only want to have this copied once, especially since
// it's not guaranteed that it also works in later invocations -- at least the
// aux part doesn't)
remoteptr
.take()
.map(|r| r.as_mut_ptr())
.unwrap_or(core::ptr::null_mut()),
auxptr
.take()
.map(|r| r as *mut _)
.unwrap_or(core::ptr::null_mut()),
)
})
.negative_to_error()
{
Err(crate::error::EAGAIN) => {
// We could accommodate that if we kept the cursor in the
// ReceiveIntoArgs, but as it's probably not the async RIOT API's
// intention to ever do this, why waste anything on it.
debug_assert!(
cursor == 0,
"sock_udp_recv_buf indicated availability of
partial datagram before complete reception"
);
// When setting all this up, we got a &mut self, so we can be sure that there
// is no other thread or task simultaneously trying to receive on this, or even
// doing a blocking send on it (which we currently don't do anyway).
//
// (Otherwise, we'd have to worry about overwriting a callback).
unsafe {
riot_sys::sock_udp_set_cb(sock, Some(Self::callback), arg);
}
return core::task::Poll::Pending;
}
Err(e) => {
debug_assert!(cursor == 0, "Late error in sock_udp_recv_buf execution");
return core::task::Poll::Ready(Err(e));
}
Ok(0) => {
// unsafe: sock_udp_recv_buf_aux was successful
let remote: UdpEp = unsafe { remote.assume_init() }.into();
assert!(aux.flags & riot_sys::SOCK_AUX_GET_LOCAL as riot_sys::sock_aux_flags_t == 0, "Sock backend must provide local addresses (should be enabled through the `sock_aux_local` module)");
let local: UdpEp = aux.local.into();
return core::task::Poll::Ready(Ok((cursor, local.into(), remote.into())));
}
Ok(n) => {
let n = n as _;
if let Some(remaining_bytes) = self.buffer.len().checked_sub(cursor) {
let to_be_copied = core::cmp::min(remaining_bytes, n);
self.buffer[cursor..cursor + to_be_copied].copy_from_slice(unsafe {
core::slice::from_raw_parts(data as *const u8, to_be_copied)
});
}
cursor += n;
}
}
}
}
}
impl ReceiveIntoArgs<'_> {
unsafe extern "C" fn callback(
_sock: *mut sock_udp_t,
flags: riot_sys::sock_async_flags_t,
arg: *mut riot_sys::libc::c_void,
) {
if flags & riot_sys::inline::SOCK_ASYNC_MSG_RECV == 0 {
// We can get stray _MSG_SENT in here (although I'm not sure those even get
// generated currently). Waking once would do no harm, as the polling function
// would just find that the socket is surprisingly not ready and register the
// callback anew, but let's not kick that off if two instructions can prevent
// it.
return;
}
RiotStylePollStruct::<Self>::callback(arg);
}
}
impl Drop for ReceiveIntoArgs<'_> {
fn drop(&mut self) {
let sock: &mut sock_udp_t = self.sock;
unsafe {
riot_sys::sock_udp_set_cb(sock, None, core::ptr::null_mut());
}
// No need to drop our fields individually, they're all just references. But if we
// had any, we'd need to drop them only after we know that no callback will fire
// any more.
}
}
}
}
mod implementation_0_7 {
implementation_module! {embedded_nal_async_0_7}
}