Add Read and Write for Async TunInterface

Those features are implemented using AsyncFD. While write doesn't
require a mutable reference to self, read does.

Make Async Tun a feature

remove async tun from workspace

rename write/read to send/recv

tun/src/unix/apple/mod.rs

@@ -2,13 +2,10 @@ use byteorder::{ByteOrder, NetworkEndian};
 use fehler::throws;
 use libc::{c_char, iovec, writev, AF_INET, AF_INET6};
 use socket2::{Domain, SockAddr, Socket, Type};
-use std::io::{IoSlice, Write};
+use std::io::IoSlice;
 use std::net::{Ipv4Addr, SocketAddrV4};
 use std::os::fd::{AsRawFd, RawFd};
-use std::{
-    io::{Error},
-    mem,
-};
+use std::{io::Error, mem};
 
 mod kern_control;
 mod sys;
@@ -130,11 +127,9 @@ impl TunInterface {
 
         self.perform(|fd| unsafe { sys::if_set_netmask(fd, &iff) })?;
     }
-}
 
-impl Write for TunInterface {
     #[throws]
-    fn write(&mut self, buf: &[u8]) -> usize {
+    pub fn send(&self, buf: &[u8]) -> usize {
         use std::io::ErrorKind;
         let proto = match buf[0] >> 4 {
             6 => Ok(AF_INET6),
@@ -156,10 +151,6 @@ impl Write for TunInterface {
             .try_into()
             .map_err(|_| Error::new(ErrorKind::Other, "Conversion error"))?
     }
-
-    fn flush(&mut self) -> std::io::Result<()> {
-        Ok(())
-    }
 }
 
 #[cfg(test)]

tun/src/unix/linux/mod.rs

@@ -166,17 +166,11 @@ impl TunInterface {
         let socket = Socket::new(Domain::IPV6, Type::DGRAM, None)?;
         perform(socket.as_raw_fd())?
     }
-}
 
-impl Write for TunInterface {
     #[throws]
-    fn write(&mut self, buf: &[u8]) -> usize {
+    pub fn send(&self, buf: &[u8]) -> usize {
         self.socket.send(buf)?
     }
-
-    fn flush(&mut self) -> std::io::Result<()> {
-        Ok(())
-    }
 }
 
 #[cfg(test)]

tun/src/unix/mod.rs

@@ -40,13 +40,8 @@ impl IntoRawFd for TunInterface {
 }
 
 impl TunInterface {
-    // #[throws]
-    // pub fn write(&self, buf: &[u8]) -> usize {
-    //     self.socket.send(buf)?
-    // }
-
     #[throws]
-    pub fn read(&mut self, buf: &mut [u8]) -> usize {
+    pub fn recv(&mut self, buf: &mut [u8]) -> usize {
         self.socket.read(buf)?
     }
 }
@@ -72,7 +67,6 @@ pub fn string_to_ifname(name: &str) -> [libc::c_char; libc::IFNAMSIZ] {
 mod test {
 
     use super::*;
-    use std::io::Write;
 
     use std::net::Ipv4Addr;
 
@@ -88,7 +82,7 @@ mod test {
         println!("tun ip: {:?}", tun.ipv4_addr()?);
         println!("Waiting for a packet...");
         let buf = &mut [0u8; 1500];
-        let res = tun.read(buf);
+        let res = tun.recv(buf);
         println!("Received!");
         assert!(res.is_ok());
     }
@@ -96,10 +90,10 @@ mod test {
     #[test]
     #[throws]
     fn write_packets() {
-        let mut tun = TunInterface::new()?;
+        let tun = TunInterface::new()?;
         let mut buf = [0u8; 1500];
         buf[0] = 6 << 4;
-        let bytes_written = tun.write(&buf)?;
+        let bytes_written = tun.send(&buf)?;
         assert_eq!(bytes_written, 1504);
     }
 }