Add async unix send/recv apis for unix

Since unix uses AsyncFd from tokio, it is easier to wait for Ready
on AsyncFd and call sync send/recv apis

This commit does not take care of windows, which is not as straight-forward as posix variants.

src/async/unix_device.rs

@@ -17,6 +17,7 @@ use core::task::{Context, Poll};
 use futures_core::ready;
 use std::io::{IoSlice, Read, Write};
 use tokio::io::unix::AsyncFd;
+use tokio::io::Interest;
 use tokio::io::{AsyncRead, AsyncWrite, ReadBuf};
 use tokio_util::codec::Framed;
 
@@ -59,6 +60,24 @@ impl AsyncDevice {
  // associate mtu with the capacity of ReadBuf
  Framed::with_capacity(self, codec, mtu as usize)
  }
+
+ /// Recv a packet from tun device
+ pub async fn recv(&self, buf: &mut [u8]) -> std::io::Result<usize> {
+ let guard = self.inner.readable().await?;
+ guard
+ .get_ref()
+ .async_io(Interest::READABLE, |inner| inner.recv(buf))
+ .await
+ }
+
+ /// Send a packet to tun device
+ pub async fn send(&self, buf: &[u8]) -> std::io::Result<usize> {
+ let guard = self.inner.writable().await?;
+ guard
+ .get_ref()
+ .async_io(Interest::WRITABLE, |inner| inner.send(buf))
+ .await
+ }
 }
 
 impl AsyncRead for AsyncDevice {

src/async/win_device.rs

@@ -60,6 +60,16 @@ impl AsyncDevice {
  // guarantee to avoid the mtu of wintun may far away larger than the default provided capacity of ReadBuf of Framed
  Framed::with_capacity(self, codec, mtu as usize)
  }
+
+ /// Recv a packet from tun device - Not implemented for windows
+ pub async fn recv(&self, buf: &mut [u8]) -> std::io::Result<usize> {
+ unimplemented!()
+ }
+
+ /// Send a packet to tun device - Not implemented for windows
+ pub async fn send(&self, buf: &[u8]) -> std::io::Result<usize> {
+ unimplemented!()
+ }
 }
 
 impl AsyncRead for AsyncDevice {