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// Copyright 2017 Sopium
// This file is part of WireGuard.rs.
// WireGuard.rs is free software: you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
// WireGuard.rs is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with WireGuard.rs. If not, see <https://www.gnu.org/licenses/>.
//! Tun device support. (Linux only for now.)
extern crate nix;
use self::nix::fcntl::{self, FcntlArg, OFlag, fcntl, open};
use self::nix::libc::{c_int, c_short};
use self::nix::sys::stat::Mode;
use self::nix::unistd::{close, read, write};
use std::ffi::{CStr, CString};
use std::io::{Error, ErrorKind, Read, Result, Write};
use std::mem;
use std::os::unix::io::{AsRawFd, IntoRawFd, RawFd};
// Hide in a mod.
mod ioctl {
use super::*;
ioctl!(write tunsetiff with b'T', 202; c_int);
}
const IFF_TUN: c_short = 0x0001;
const IFF_NO_PI: c_short = 0x1000;
#[repr(C)]
struct ifreq {
name: [u8; 16], // Use u8 becuase that's what CString and CStr wants.
flags: c_short,
}
/// A linux tun device.
#[derive(Debug)]
pub struct Tun {
fd: i32,
name: String,
}
/// The file descriptor will be closed when the Tun is dropped.
impl Drop for Tun {
fn drop(&mut self) {
// Ignore error...
let _ = close(self.fd);
}
}
impl Tun {
/// Create a tun device.
/// O_CLOEXEC, IFF_NO_PI.
pub fn create<S>(name: Option<S>) -> Result<Tun>
where S: AsRef<str>
{
let name = name.as_ref().map(AsRef::as_ref);
if let Some(n) = name {
// IFNAMESIZ is 16.
if n.len() > 15 {
return Err(Error::new(ErrorKind::InvalidInput, "device name is too long"));
}
}
let name =
CString::new(name.unwrap_or("")).map_err(|e| Error::new(ErrorKind::InvalidInput, e))?;
let name = name.as_bytes_with_nul();
let fd = open("/dev/net/tun",
fcntl::O_RDWR | fcntl::O_CLOEXEC,
Mode::empty())?;
let mut ifr = ifreq {
name: [0; 16],
flags: IFF_TUN | IFF_NO_PI,
};
ifr.name[..name.len()].copy_from_slice(name);
unsafe { ioctl::tunsetiff(fd, &ifr as *const ifreq as *const c_int) }?;
let namelen = ifr.name.iter().position(|x| *x == 0).unwrap() + 1;
let name = CStr::from_bytes_with_nul(&ifr.name[..namelen])
.unwrap().to_str().unwrap().to_string();
Ok(Tun {
fd: fd,
name: name,
})
}
/// Get name of this device. Should be the same name if you have
/// passed one in when createing the device.
pub fn get_name(&self) -> &str {
self.name.as_str()
}
/// Set non-blocking mode for this device.
pub fn set_nonblocking(&self, nb: bool) -> Result<()> {
let flags = fcntl(self.fd, FcntlArg::F_GETFL)?;
let flags = OFlag::from_bits(flags).unwrap();
let flags = if nb {
flags | fcntl::O_NONBLOCK
} else {
flags & !fcntl::O_NONBLOCK
};
fcntl(self.fd, FcntlArg::F_SETFL(flags))?;
Ok(())
}
}
impl AsRawFd for Tun {
fn as_raw_fd(&self) -> RawFd {
self.fd
}
}
impl IntoRawFd for Tun {
fn into_raw_fd(self) -> RawFd {
let fd = self.fd;
mem::forget(self);
fd
}
}
impl Tun {
/// Read a packet from the tun device.
pub fn read(&self, buf: &mut [u8]) -> Result<usize> {
Ok(read(self.fd, buf)?)
}
/// Write a packet to tun device.
pub fn write(&self, buf: &[u8]) -> Result<usize> {
Ok(write(self.fd, buf)?)
}
}
impl Read for Tun {
fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
Tun::read(self, buf)
}
}
impl<'a> Read for &'a Tun {
fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
Tun::read(self, buf)
}
}
impl Write for Tun {
fn write(&mut self, buf: &[u8]) -> Result<usize> {
Tun::write(self, buf)
}
/// flush() for Tun is a no-op.
fn flush(&mut self) -> Result<()> {
Ok(())
}
}
impl<'a> Write for &'a Tun {
fn write(&mut self, buf: &[u8]) -> Result<usize> {
Tun::write(self, buf)
}
fn flush(&mut self) -> Result<()> {
Ok(())
}
}
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