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|
use super::super::tun::*;
use libc::*;
use std::error::Error;
use std::fmt;
use std::os::raw::c_short;
use std::os::unix::io::RawFd;
use std::sync::atomic::{AtomicUsize, Ordering};
use std::sync::Arc;
const IFNAMSIZ: usize = 16;
const TUNSETIFF: u64 = 0x4004_54ca;
const IFF_UP: i16 = 0x1;
const IFF_RUNNING: i16 = 0x40;
const IFF_TUN: c_short = 0x0001;
const IFF_NO_PI: c_short = 0x1000;
const CLONE_DEVICE_PATH: &'static [u8] = b"/dev/net/tun\0";
const TUN_MAGIC: u8 = b'T';
const TUN_SET_IFF: u8 = 202;
#[repr(C)]
struct Ifreq {
name: [u8; libc::IFNAMSIZ],
flags: c_short,
_pad: [u8; 64],
}
pub struct LinuxTun {}
pub struct LinuxTunReader {
fd: RawFd,
}
pub struct LinuxTunWriter {
fd: RawFd,
}
/* Listens for netlink messages
* announcing an MTU update for the interface
*/
#[derive(Clone)]
pub struct LinuxTunMTU {
value: Arc<AtomicUsize>,
}
#[derive(Debug)]
pub enum LinuxTunError {
InvalidTunDeviceName,
FailedToOpenCloneDevice,
SetIFFIoctlFailed,
Closed, // TODO
}
impl fmt::Display for LinuxTunError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
LinuxTunError::InvalidTunDeviceName => write!(f, "Invalid name (too long)"),
LinuxTunError::FailedToOpenCloneDevice => {
write!(f, "Failed to obtain fd for clone device")
}
LinuxTunError::SetIFFIoctlFailed => {
write!(f, "set_iff ioctl failed (insufficient permissions?)")
}
LinuxTunError::Closed => write!(f, "The tunnel has been closed"),
}
}
}
impl Error for LinuxTunError {
fn description(&self) -> &str {
unimplemented!()
}
fn source(&self) -> Option<&(dyn Error + 'static)> {
unimplemented!()
}
}
impl MTU for LinuxTunMTU {
#[inline(always)]
fn mtu(&self) -> usize {
self.value.load(Ordering::Relaxed)
}
}
impl Reader for LinuxTunReader {
type Error = LinuxTunError;
fn read(&self, buf: &mut [u8], offset: usize) -> Result<usize, Self::Error> {
debug_assert!(
offset < buf.len(),
"There is no space for the body of the read"
);
let n: isize =
unsafe { read(self.fd, buf[offset..].as_mut_ptr() as _, buf.len() - offset) };
if n < 0 {
Err(LinuxTunError::Closed)
} else {
// conversion is safe
Ok(n as usize)
}
}
}
impl Writer for LinuxTunWriter {
type Error = LinuxTunError;
fn write(&self, src: &[u8]) -> Result<(), Self::Error> {
match unsafe { write(self.fd, src.as_ptr() as _, src.len() as _) } {
-1 => Err(LinuxTunError::Closed),
_ => Ok(()),
}
}
}
impl Tun for LinuxTun {
type Error = LinuxTunError;
type Reader = LinuxTunReader;
type Writer = LinuxTunWriter;
type MTU = LinuxTunMTU;
}
impl PlatformTun for LinuxTun {
fn create(name: &str) -> Result<(Vec<Self::Reader>, Self::Writer, Self::MTU), Self::Error> {
// construct request struct
let mut req = Ifreq {
name: [0u8; libc::IFNAMSIZ],
flags: (libc::IFF_TUN | libc::IFF_NO_PI) as c_short,
_pad: [0u8; 64],
};
// sanity check length of device name
let bs = name.as_bytes();
if bs.len() > libc::IFNAMSIZ - 1 {
return Err(LinuxTunError::InvalidTunDeviceName);
}
req.name[..bs.len()].copy_from_slice(bs);
// open clone device
let fd: RawFd = match unsafe { open(CLONE_DEVICE_PATH.as_ptr() as _, O_RDWR) } {
-1 => return Err(LinuxTunError::FailedToOpenCloneDevice),
fd => fd,
};
assert!(fd >= 0);
// create TUN device
if unsafe { ioctl(fd, TUNSETIFF as _, &req) } < 0 {
return Err(LinuxTunError::SetIFFIoctlFailed);
}
// create PlatformTunMTU instance
Ok((
vec![LinuxTunReader { fd }], // TODO: enable multi-queue for Linux
LinuxTunWriter { fd },
LinuxTunMTU {
value: Arc::new(AtomicUsize::new(1500)), // TODO: fetch and update
},
))
}
}
#[cfg(test)]
mod tests {
use super::*;
use std::env;
fn is_root() -> bool {
match env::var("USER") {
Ok(val) => val == "root",
Err(_) => false,
}
}
#[test]
fn test_tun_create() {
if !is_root() {
return;
}
let (readers, writers, mtu) = LinuxTun::create("test").unwrap();
// TODO: test (any good idea how?)
}
}
|
