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ifaddrs.rs
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ifaddrs.rs
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//! Query network interface addresses
//!
//! Uses the Linux and/or BSD specific function `getifaddrs` to query the list
//! of interfaces and their associated addresses.
use cfg_if::cfg_if;
use std::ffi;
use std::iter::Iterator;
use std::marker::PhantomData;
use std::mem;
use std::option::Option;
use crate::net::if_::*;
use crate::sys::socket::RawAddr;
use crate::{Errno, Result};
/// Describes a single address for an interface as returned by `getifaddrs`.
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct InterfaceAddress<'a> {
/// Name of the network interface
pub interface_name: String,
/// Flags as from `SIOCGIFFLAGS` ioctl
pub flags: InterfaceFlags,
/// Network address of this interface
pub address: Option<RawAddr<'a>>,
/// Netmask of this interface
pub netmask: Option<RawAddr<'a>>,
/// Broadcast address of this interface, if applicable
pub broadcast: Option<RawAddr<'a>>,
/// Point-to-point destination address
pub destination: Option<RawAddr<'a>>,
}
cfg_if! {
if #[cfg(any(target_os = "android", target_os = "emscripten", target_os = "fuchsia", target_os = "linux"))] {
fn get_ifu_from_sockaddr(info: &libc::ifaddrs) -> *const libc::sockaddr {
info.ifa_ifu
}
} else {
fn get_ifu_from_sockaddr(info: &libc::ifaddrs) -> *const libc::sockaddr {
info.ifa_dstaddr
}
}
}
impl<'a> InterfaceAddress<'a> {
/// Create an `InterfaceAddress` from the libc struct.
fn from_libc_ifaddrs(info: &libc::ifaddrs) -> InterfaceAddress {
let ifname = unsafe { ffi::CStr::from_ptr(info.ifa_name) };
let address = unsafe { RawAddr::new(&*info.ifa_addr) };
let netmask = unsafe { RawAddr::new(&*info.ifa_netmask) };
let mut addr = InterfaceAddress {
interface_name: ifname.to_string_lossy().to_string(),
flags: InterfaceFlags::from_bits_truncate(info.ifa_flags as i32),
address,
netmask,
broadcast: None,
destination: None,
};
let ifu = get_ifu_from_sockaddr(info);
if addr.flags.contains(InterfaceFlags::IFF_POINTOPOINT) {
addr.destination = unsafe { RawAddr::new(&*ifu) };
} else if addr.flags.contains(InterfaceFlags::IFF_BROADCAST) {
addr.broadcast = unsafe { RawAddr::new(&*ifu) };
}
addr
}
}
/// Holds the results of `getifaddrs`.
///
/// Use the function `getifaddrs` to create this struct and [`Self::iter`]
/// to create the iterator. Note that the actual list of interfaces can be
/// iterated once and will be freed as soon as the Iterator goes out of scope.
#[derive(Debug)]
pub struct InterfaceAddresses {
base: *mut libc::ifaddrs,
}
impl InterfaceAddresses {
/// Create an iterator over the list of interfaces.
pub fn iter(&self) -> InterfaceAddressIterator<'_> {
InterfaceAddressIterator {
next: self.base,
_a: PhantomData,
}
}
}
impl Drop for InterfaceAddresses {
fn drop(&mut self) {
unsafe { libc::freeifaddrs(self.base) };
}
}
/// Holds the results of `getifaddrs`.
///
/// Use the function `getifaddrs` to create this Iterator. Note that the
/// actual list of interfaces can be iterated once and will be freed as
/// soon as the Iterator goes out of scope.
#[derive(Debug, Eq, Hash, PartialEq)]
pub struct InterfaceAddressIterator<'a> {
next: *mut libc::ifaddrs,
_a: PhantomData<&'a ()>,
}
impl<'a> Iterator for InterfaceAddressIterator<'a> {
type Item = InterfaceAddress<'a>;
fn next(&mut self) -> Option<<Self as Iterator>::Item> {
match unsafe { self.next.as_ref() } {
Some(ifaddr) => {
self.next = ifaddr.ifa_next;
Some(InterfaceAddress::from_libc_ifaddrs(ifaddr))
}
None => None,
}
}
}
/// Get interface addresses using libc's `getifaddrs`
///
/// Note that the underlying implementation differs between OSes. Only the
/// most common address families are supported by the nix crate (due to
/// lack of time and complexity of testing). The address family is encoded
/// in the specific variant of `SockaddrStorage` returned for the fields
/// `address`, `netmask`, `broadcast`, and `destination`. For any entry not
/// supported, the returned list will contain a `None` entry.
///
/// # Example
/// ```
/// let addrs = nix::ifaddrs::getifaddrs().unwrap();
/// for ifaddr in addrs.iter() {
/// match ifaddr.address {
/// Some(address) => {
/// println!("interface {} address {}",
/// ifaddr.interface_name, address);
/// },
/// None => {
/// println!("interface {} with unsupported address family",
/// ifaddr.interface_name);
/// }
/// }
/// }
/// ```
pub fn getifaddrs() -> Result<InterfaceAddresses> {
let mut addrs = mem::MaybeUninit::<*mut libc::ifaddrs>::uninit();
unsafe {
Errno::result(libc::getifaddrs(addrs.as_mut_ptr())).map(|_| {
InterfaceAddresses {
base: addrs.assume_init(),
}
})
}
}
#[cfg(test)]
mod tests {
use std::collections::HashMap;
use super::*;
use crate::sys::socket::{AddressFamily, Ipv4Address};
// Only checks if `getifaddrs` can be invoked without panicking.
#[test]
fn test_getifaddrs() {
let _ = getifaddrs();
}
// Ensures getting the netmask works, and in particular that
// `workaround_xnu_bug` works properly.
#[test]
fn test_getifaddrs_netmask_correct() {
let addrs = getifaddrs().unwrap();
for iface in addrs.iter() {
let sock = if let Some(sock) = iface.netmask {
sock
} else {
continue;
};
if sock.family() == AddressFamily::INET {
let _ = sock.to_ipv4().unwrap();
return;
} else if sock.family() == AddressFamily::INET6 {
let _ = sock.to_ipv6().unwrap();
return;
}
}
panic!("No address?");
}
#[test]
fn test_get_ifaddrs_netmasks_eq() {
let mut netmasks = HashMap::new();
let ifs = getifaddrs().unwrap();
for ifa in ifs.iter() {
let Some(netmask) =
ifa.netmask.filter(|n| n.family() == AddressFamily::INET)
else {
continue;
};
let ipv4 = *netmask.to_ipv4().unwrap();
let [a, b, c, d] = ipv4.ip().to_be_bytes();
let x = Ipv4Address::new(a, b, c, d, ipv4.port());
assert_eq!(ipv4, x);
netmasks.insert(
ifa.interface_name.clone(),
*netmask.to_ipv4().unwrap(),
);
}
drop(ifs);
let ifs = getifaddrs().unwrap();
for ifa in ifs.iter() {
let Some(netmask) =
ifa.netmask.filter(|n| n.family() == AddressFamily::INET)
else {
continue;
};
assert_eq!(
netmasks.get(&ifa.interface_name).unwrap(),
netmask.to_ipv4().unwrap(),
);
}
}
}