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

.vscode/settings.json

@@ -19,5 +19,5 @@
     ],
     "[rust]": {
         "editor.defaultFormatter": "rust-lang.rust-analyzer",
-    },
+    }
 }

Cargo.lock

@@ -482,6 +482,21 @@ dependencies = [
  "percent-encoding",
 ]
 
+[[package]]
+name = "futures"
+version = "0.3.28"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "23342abe12aba583913b2e62f22225ff9c950774065e4bfb61a19cd9770fec40"
+dependencies = [
+ "futures-channel",
+ "futures-core",
+ "futures-executor",
+ "futures-io",
+ "futures-sink",
+ "futures-task",
+ "futures-util",
+]
+
 [[package]]
 name = "futures-channel"
 version = "0.3.28"
@@ -489,6 +504,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "955518d47e09b25bbebc7a18df10b81f0c766eaf4c4f1cccef2fca5f2a4fb5f2"
 dependencies = [
  "futures-core",
+ "futures-sink",
 ]
 
 [[package]]
@@ -497,6 +513,34 @@ version = "0.3.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4bca583b7e26f571124fe5b7561d49cb2868d79116cfa0eefce955557c6fee8c"
 
+[[package]]
+name = "futures-executor"
+version = "0.3.28"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ccecee823288125bd88b4d7f565c9e58e41858e47ab72e8ea2d64e93624386e0"
+dependencies = [
+ "futures-core",
+ "futures-task",
+ "futures-util",
+]
+
+[[package]]
+name = "futures-io"
+version = "0.3.28"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4fff74096e71ed47f8e023204cfd0aa1289cd54ae5430a9523be060cdb849964"
+
+[[package]]
+name = "futures-macro"
+version = "0.3.28"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "89ca545a94061b6365f2c7355b4b32bd20df3ff95f02da9329b34ccc3bd6ee72"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.15",
+]
+
 [[package]]
 name = "futures-sink"
 version = "0.3.28"
@@ -515,10 +559,16 @@ version = "0.3.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "26b01e40b772d54cf6c6d721c1d1abd0647a0106a12ecaa1c186273392a69533"
 dependencies = [
+ "futures-channel",
  "futures-core",
+ "futures-io",
+ "futures-macro",
+ "futures-sink",
  "futures-task",
+ "memchr",
  "pin-project-lite",
  "pin-utils",
+ "slab",
 ]
 
 [[package]]
@@ -1383,9 +1433,9 @@ checksum = "1f3ccbac311fea05f86f61904b462b55fb3df8837a366dfc601a0161d0532f20"
 
 [[package]]
 name = "tokio"
-version = "1.28.1"
+version = "1.28.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0aa32867d44e6f2ce3385e89dceb990188b8bb0fb25b0cf576647a6f98ac5105"
+checksum = "94d7b1cfd2aa4011f2de74c2c4c63665e27a71006b0a192dcd2710272e73dfa2"
 dependencies = [
  "autocfg",
  "bytes",
@@ -1472,6 +1522,7 @@ dependencies = [
  "bindgen",
  "byteorder",
  "fehler",
+ "futures",
  "lazy_static",
  "libc",
  "libloading",
@@ -1487,13 +1538,6 @@ dependencies = [
  "zip",
 ]
 
-[[package]]
-name = "tun-async"
-version = "0.1.0"
-dependencies = [
- "tun",
-]
-
 [[package]]
 name = "typenum"
 version = "1.16.0"

Cargo.toml

@@ -1,2 +1,2 @@
 [workspace]
-members = ["burrow", "tun-async", "tun"]
+members = ["burrow", "tun"]

tun-async/Cargo.toml

@@ -1,9 +0,0 @@
-[package]
-name = "tun-async"
-version = "0.1.0"
-edition = "2021"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[dependencies]
-tun = { version = "0.1", path = "../tun" }

tun-async/src/lib.rs

@@ -1,14 +0,0 @@
-pub fn add(left: usize, right: usize) -> usize {
-    left + right
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn it_works() {
-        let result = add(2, 2);
-        assert_eq!(result, 4);
-    }
-}

tun/Cargo.toml

@@ -12,6 +12,14 @@ tokio = { version = "1.28", features = [] }
 byteorder = "1.4"
 log = "0.4"
 
+futures = { version = "0.3.28", optional = true }
+
+[features]
+tokio = ["tokio/net", "dep:futures"]
+
+[target.'cfg(feature = "tokio")'.dev-dependencies]
+tokio = { features = ["rt", "macros"] }
+
 [target.'cfg(windows)'.dependencies]
 lazy_static = "1.4"
 libloading = "0.7"

tun/src/lib.rs

@@ -8,5 +8,9 @@ pub(crate) mod imp;
 
 mod options;
 
+#[cfg(any(target_os = "linux", target_vendor = "apple"))]
+#[cfg(feature = "tokio")]
+pub mod tokio;
+
 pub use imp::{TunInterface, TunQueue};
 pub use options::TunOptions;

tun/src/tokio/mod.rs

@@ -0,0 +1,58 @@
+use std::io;
+use tokio::io::unix::AsyncFd;
+
+pub struct TunInterface {
+    inner: AsyncFd<crate::TunInterface>,
+}
+
+impl TunInterface {
+    pub fn new(tun: crate::TunInterface) -> io::Result<Self> {
+        Ok(Self {
+            inner: AsyncFd::new(tun)?,
+        })
+    }
+
+    pub async fn write(&self, buf: &[u8]) -> io::Result<usize> {
+        loop {
+            let mut guard = self.inner.writable().await?;
+            match guard.try_io(|inner| inner.get_ref().send(buf)) {
+                Ok(result) => return result,
+                Err(_would_block) => continue,
+            }
+        }
+    }
+
+    pub async fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        loop {
+            let mut guard = self.inner.readable_mut().await?;
+            match guard.try_io(|inner| (*inner).get_mut().recv(buf)) {
+                Ok(result) => return result,
+                Err(_would_block) => continue,
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::net::Ipv4Addr;
+
+    use super::*;
+    #[tokio::test]
+    async fn test_create() {
+        let tun = crate::TunInterface::new().unwrap();
+        let _async_tun = TunInterface::new(tun).unwrap();
+    }
+
+    #[tokio::test]
+    async fn test_write() {
+        let tun = crate::TunInterface::new().unwrap();
+        tun.set_ipv4_addr(Ipv4Addr::from([192, 168, 1, 10]))
+            .unwrap();
+        let async_tun = TunInterface::new(tun).unwrap();
+        let mut buf = [0u8; 1500];
+        buf[0] = 6 << 4;
+        let bytes_written = async_tun.write(&buf).await.unwrap();
+        assert!(bytes_written > 0);
+    }
+}

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);
     }
 }

tun/tests/configure.rs

@@ -1,6 +1,6 @@
 use fehler::throws;
 use std::io::Error;
-use std::net::{Ipv4Addr, Ipv6Addr};
+use std::net::{Ipv4Addr};
 use tun::TunInterface;
 
 #[test]
@@ -23,6 +23,7 @@ fn test_set_get_ipv4() {
 
 #[test]
 #[throws]
+#[cfg(target_os = "linux")]
 fn test_set_get_ipv6() {
     let tun = TunInterface::new()?;