[quicktap-cli] slight refactor in prep for tunneling + routing

quicktap-cli/src/device.rs

@@ -0,0 +1,28 @@
+use std::error::Error;
+use std::io;
+use std::net::Ipv4Addr;
+
+use quicktap::cidr::{IpInet, Ipv4Inet};
+use quicktap::drivers::tun::TunDevice;
+use quicktap::drivers::tungeneric::{GenericDriver, GenericInterface};
+
+pub fn packet_eventloop() -> Result<(), Box<dyn Error>> {
+    let mut device = TunDevice::new(&GenericInterface {
+        addresses: vec![IpInet::V4(Ipv4Inet::new(Ipv4Addr::new(10, 19, 2, 2), 16).unwrap())],
+        mtu: None,
+        name: "ela1".to_string(),
+    }).unwrap();
+    loop {
+        let packet = match device.read() {
+            Ok(p) => Some(p),
+            Err(e) => match e.kind() {
+                io::ErrorKind::WouldBlock => None,
+                _ => return Err(e.into())
+            }
+        };
+
+        if let Some(p) = packet {
+            println!("{:?}", p.header);
+        }
+    }
+}

quicktap-cli/src/main.rs

@@ -1,15 +1,13 @@
-use std::net::{Ipv4Addr};
+use std::net::Ipv4Addr;
+
 use quicktap::cidr::{IpInet, Ipv4Inet};
 use quicktap::drivers::tun::TunDevice;
 use quicktap::drivers::tungeneric::{GenericDriver, GenericInterface};
 
+use crate::device::packet_eventloop;
+
+pub mod device;
+
 fn main() {
-    let mut device = TunDevice::new(&GenericInterface {
-        addresses: vec![IpInet::V4(Ipv4Inet::new(Ipv4Addr::new(10, 19, 2, 2), 16).unwrap())],
-        mtu: None,
-        name: "ela1".to_string(),
-    }).unwrap();
-    loop {
-        println!("{:?}", device.read().unwrap().header)
-    }
+    packet_eventloop().unwrap();
 }

quicktap/src/drivers/linux.rs

@@ -3,8 +3,10 @@
 use std::error::Error;
 use std::io;
 use std::io::{Read, Write};
+
 use etherparse::IpHeader;
 use tun::platform::Device;
+
 use crate::drivers::tungeneric::{GenericDriver, GenericInterface, TunPacket};
 
 #[allow(clippy::module_name_repetitions)]
@@ -31,15 +33,18 @@ impl GenericDriver for TunDevice {
         if let Some(mtu) = config.mtu {
             device_config.mtu(mtu);
         }
+        let device = tun::create(&device_config)?;
+        device.set_nonblock()?;
+
         Ok(Self {
-            device: tun::create(&device_config)?,
+            device,
             read_buf: [0u8; 4096],
             read_offset: 0,
             packet_buf: [0u8; 4096],
         })
     }
 
-    fn read(&mut self) -> Result<TunPacket, Box<dyn Error>> {
+    fn read(&mut self) -> Result<TunPacket, io::Error> {
         self.packet_buf = [0u8; 4096];
         let _ = self.device.read(&mut self.packet_buf)?;
         let ip_header = IpHeader::from_slice(&self.packet_buf);
@@ -53,7 +58,7 @@ impl GenericDriver for TunDevice {
             })
         }
 
-        Err(io::Error::new(io::ErrorKind::WouldBlock, "No packets detected yet").into())
+        Err(io::Error::new(io::ErrorKind::WouldBlock, "No packets detected yet"))
     }
 
     fn clear(&mut self) {
@@ -61,7 +66,7 @@ impl GenericDriver for TunDevice {
         self.read_offset = 0;
     }
 
-    fn write(&mut self, packet: TunPacket) -> Result<(), Box<dyn Error>> {
+    fn write(&mut self, packet: TunPacket) -> Result<(), io::Error> {
         let _ = self.device.write(&packet.packet)?;
         Ok(())
     }

quicktap/src/drivers/tungeneric.rs

@@ -1,8 +1,10 @@
 //! Generic traits and modules to represent a tun/tap device
 
 use std::error::Error;
+use std::io;
+
 use cidr::IpInet;
-use etherparse::{IpHeader};
+use etherparse::IpHeader;
 
 #[derive(Debug)]
 /// A parsed packet from an interface
@@ -24,7 +26,7 @@ pub trait GenericDriver {
     /// Upon finding a successful packet inside the internal buffer, or the .clear() method being called, the internal buffer will be cleared.
     /// # Errors
     /// This function will return `WouldBlock` if a packet could not be read. This function may error if there is an error reading the interface.
-    fn read(&mut self) -> Result<TunPacket, Box<dyn Error>>;
+    fn read(&mut self) -> Result<TunPacket, io::Error>;
 
     /// Clear any internal state of this interface.
     fn clear(&mut self);
@@ -32,7 +34,7 @@ pub trait GenericDriver {
     /// Attempt to write a packet to the interface.
     /// # Errors
     /// This function will error if an error occured writing to the device.
-    fn write(&mut self, packet: TunPacket) -> Result<(), Box<dyn Error>>;
+    fn write(&mut self, packet: TunPacket) -> Result<(), io::Error>;
 }
 
 /// Generic interface config