udp_async: Implement async traits of upcoming async-embedded-nal > 0.3

See-Also: rust-embedded-community/embedded-nal#73

Author: chrysn

Cargo.toml

@@ -2,7 +2,7 @@
 name = "std-embedded-nal"
 version = "0.1.3"
 authors = ["chrysn <[email protected]>"]
-edition = "2018"
+edition = "2021"
 
 description = "Implementation of the `embedded-nal` traits for large devices that support the standard library"
 categories = ["embedded", "hardware-support"]
@@ -12,15 +12,19 @@ repository = "https://gitlab.com/chrysn/std-embedded-nal"
 
 [dependencies]
 embedded-nal = "0.6"
-embedded-nal-async = { version = "0.1", optional = true }
+embedded-nal-async = { git = "https://github.com/rust-embedded-community/embedded-nal", optional = true }
+embedded-io = { version = "0.4", optional = true, features = [ "std" ] }
 async-std = { version = "1.12", optional = true }
 # If enabled, these traits are implemented as well; they're experimental and
 # will hopefully wind up in alter embedded-nal versions, so enabling this has
 # no stability guarantees.
 embedded-nal-tcpextensions = { version = "0.1", optional = true }
 
+async-io = "^1.9"
+nix = { version = "0.25", features = [ "socket", "net", "uio" ] }
+
 [features]
-async = [ "embedded-nal-async", "async-std" ]
+async = [ "embedded-nal-async", "async-std", "embedded-io" ]
 
 [dev-dependencies]
 mio = { version = "0.8", features = [ "os-ext" ] }

examples/coapclient_async.rs

@@ -1,24 +1,24 @@
 //! A brutally oversimplified CoAP client that GETs /.well-known/core from localhost:5683
 
-use embedded_nal_async::UdpClientStack;
+use embedded_nal_async::{UdpStack, ConnectedUdp};
 
 async fn run<S, E>(stack: &mut S) -> Result<(), E>
 where
     E: core::fmt::Debug, // Might go away when MSRV goes up to 1.49, see https://github.com/rust-lang/rust/issues/80821
-    S: UdpClientStack<Error = E>,
+    S: UdpStack<Error = E>,
+    S::Connected: ConnectedUdp<Error = E>,
 {
     let target = embedded_nal::SocketAddr::new(
         "::1".parse().unwrap(),
         5683,
     );
 
-    let mut sock = stack.socket().await?;
-    stack.connect(&mut sock, target).await?;
+    let (_local, mut sock) = stack.connect(target).await?;
     // Data, V1 NON no token, GET, message ID 0x0000, 2x Uri-Path
-    stack.send(&mut sock, b"\x50\x01\0\0\xbb.well-known\x04core").await?;
+    sock.send(b"\x50\x01\0\0\xbb.well-known\x04core").await?;
 
     let mut respbuf = [0; 1500];
-    let (resplen, _) = stack.receive(&mut sock, &mut respbuf).await?;
+    let resplen = sock.receive_into(&mut respbuf).await?;
     let response = &respbuf[..resplen];
 
     println!("Response: {}", String::from_utf8_lossy(response));

src/conversion.rs

@@ -26,6 +26,31 @@ impl From<embedded_nal::IpAddr> for IpAddr {
     }
 }
 
+// That this is missing zone info on IPv6 probably just makes std::net::IpAddr a bad intermediate
+// type.
+impl From<nix::libc::in6_pktinfo> for IpAddr {
+    fn from(input: nix::libc::in6_pktinfo) -> Self {
+        // FIXME why isn't this having zone infos??
+        Self(input.ipi6_addr.s6_addr.into())
+    }
+}
+
+impl From<IpAddr> for nix::libc::in6_pktinfo {
+    fn from(input: IpAddr) -> nix::libc::in6_pktinfo {
+        let input = match input.0 {
+            std::net::IpAddr::V6(a) => a,
+            _ => panic!("IPv6 only so far"),
+        };
+        nix::libc::in6_pktinfo {
+            ipi6_addr: nix::libc::in6_addr {
+                s6_addr: input.octets(),
+            },
+            // FIXME and here it really hurts
+            ipi6_ifindex: 0,
+        }
+    }
+}
+
 impl From<IpAddr> for embedded_nal::IpAddr {
     fn from(s: IpAddr) -> embedded_nal::IpAddr {
         match s.0 {

src/lib.rs

@@ -9,9 +9,7 @@
 //! All implementations use `std::io::Error` as their error type.
 //!
 //! [embedded-nal]: https://crates.io/crates/embedded-nal
-#![cfg_attr(feature = "async", feature(generic_associated_types))] // for implementing -async
-#![cfg_attr(feature = "async", feature(type_alias_impl_trait))] // as async blocks
-                                                                             // don't provide types
+#![cfg_attr(feature = "async", feature(async_fn_in_trait))]
 
 mod conversion;
 mod dns;