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#![cfg(any(target_os = "linux", target_os = "macos"))]
#[cfg(target_os = "linux")]
use std::ffi::c_ulong;
use std::{ffi::c_uint, io, os::fd::AsRawFd};
use nix::{errno::Errno, net::if_::if_nametoindex};
use socket2::Domain;
use talpid_types::ErrorExt;
/// Converts an interface name into the corresponding index.
pub fn iface_index(name: &str) -> Result<c_uint, IfaceIndexLookupError> {
if_nametoindex(name).map_err(|error| IfaceIndexLookupError {
interface_name: name.to_owned(),
error,
})
}
#[derive(Debug, thiserror::Error)]
#[error("Failed to get index for interface {interface_name}: {error}")]
pub struct IfaceIndexLookupError {
pub interface_name: String,
pub error: Errno,
}
#[cfg(target_os = "macos")]
const SIOCSIFMTU: u64 = 0x80206934;
#[cfg(target_os = "macos")]
const SIOCGIFMTU: u64 = 0xc0206933;
#[cfg(target_os = "linux")]
const SIOCSIFMTU: c_ulong = libc::SIOCSIFMTU;
#[cfg(target_os = "linux")]
const SIOCGIFMTU: c_ulong = libc::SIOCSIFMTU;
pub fn set_mtu(interface_name: &str, mtu: u16) -> Result<(), io::Error> {
let sock = socket2::Socket::new(
Domain::IPV4,
socket2::Type::STREAM,
Some(socket2::Protocol::TCP),
)?;
// SAFETY: ifreq is a C struct, these can safely be zeroed.
let mut ifr: libc::ifreq = unsafe { std::mem::zeroed() };
if interface_name.len() >= ifr.ifr_name.len() {
return Err(io::Error::new(
io::ErrorKind::InvalidInput,
"Interface name too long",
));
}
// SAFETY: `interface_name.len()` is less than `ifr.ifr_name.len()`
unsafe {
std::ptr::copy_nonoverlapping(
interface_name.as_ptr() as *const libc::c_char,
&mut ifr.ifr_name as *mut _,
interface_name.len(),
)
};
ifr.ifr_ifru.ifru_mtu = mtu as i32;
// For some reason, libc crate defines ioctl to take a c_int (which is defined as i32), but the c_ulong type is defined as u64:
// https://docs.rs/libc/latest/x86_64-unknown-linux-musl/libc/fn.ioctl.html
// https://docs.rs/libc/latest/x86_64-unknown-linux-musl/libc/type.c_ulong.html
// https://docs.rs/libc/latest/x86_64-unknown-linux-musl/libc/constant.SIOCSIFMTU.html
#[allow(clippy::useless_conversion)]
let request = SIOCSIFMTU.try_into().unwrap();
// SAFETY: SIOCSIFMTU expects an ifreq with an MTU and interface set
if unsafe { libc::ioctl(sock.as_raw_fd(), request, &ifr) } < 0 {
let e = std::io::Error::last_os_error();
log::error!("{}", e.display_chain_with_msg("SIOCSIFMTU failed"));
return Err(e);
}
Ok(())
}
pub fn get_mtu(interface_name: &str) -> Result<u16, io::Error> {
let sock = socket2::Socket::new(
Domain::IPV4,
socket2::Type::STREAM,
Some(socket2::Protocol::TCP),
)?;
// SAFETY: ifreq is a C struct, these can safely be zeroed.
let mut ifr: libc::ifreq = unsafe { std::mem::zeroed() };
if interface_name.len() >= ifr.ifr_name.len() {
return Err(io::Error::new(
io::ErrorKind::InvalidInput,
"Interface name too long",
));
}
// SAFETY: `interface_name.len()` is less than `ifr.ifr_name.len()`
unsafe {
std::ptr::copy_nonoverlapping(
interface_name.as_ptr() as *const libc::c_char,
&mut ifr.ifr_name as *mut _,
interface_name.len(),
)
};
// For some reason, libc crate defines ioctl to take a c_int (which is defined as i32), but the c_ulong type is defined as u64:
// https://docs.rs/libc/latest/x86_64-unknown-linux-musl/libc/fn.ioctl.html
// https://docs.rs/libc/latest/x86_64-unknown-linux-musl/libc/type.c_ulong.html
// https://docs.rs/libc/latest/x86_64-unknown-linux-musl/libc/constant.SIOCGIFMTU.html
#[allow(clippy::useless_conversion)]
let request = SIOCGIFMTU.try_into().unwrap();
// SAFETY: SIOCGIFMTU expects an ifreq with an interface set
if unsafe { libc::ioctl(sock.as_raw_fd(), request, &ifr) } < 0 {
let e = std::io::Error::last_os_error();
log::error!("{}", e.display_chain_with_msg("SIOCGIFMTU failed"));
return Err(e);
}
// SAFETY: ifru_mtu is initialized by SIOCGIFMTU
Ok(u16::try_from(unsafe { ifr.ifr_ifru.ifru_mtu }).unwrap())
}
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