1//! Low-level Linux network device access
2//!
3//! The methods in this module take a socket's file descriptor to communicate
4//! with the kernel in their ioctl call:
5//! - glibc uses an `AF_UNIX`, `AF_INET`, or `AF_INET6` socket. The address
6//! family itself does not matter and glibc tries the next address family if
7//! socket creation with one fails.
8//! - Android (bionic) uses an `AF_INET` socket.
9//! - Both create the socket with `SOCK_DGRAM|SOCK_CLOEXEC` type/flag.
10//! - The [manual pages] specify that the ioctl calls “can be used on any
11//! socket's file descriptor regardless of the family or type”.
12//!
13//! # References
14//! - [Linux]
15//!
16//! [manual pages]: https://man7.org/linux/man-pages/man7/netdevice.7.html
17//! [Linux]: https://man7.org/linux/man-pages/man7/netdevice.7.html
18
19use crate::fd::AsFd;
20use crate::io;
21#[cfg(feature = "alloc")]
22use alloc::string::String;
23
24/// `ioctl(fd, SIOCGIFINDEX, ifreq)`—Returns the interface index for a given
25/// name.
26///
27/// See the [module-level documentation] for information about `fd` usage.
28///
29/// # References
30/// - [Linux]
31///
32/// [module-level documentation]: self
33/// [Linux]: https://man7.org/linux/man-pages/man7/netdevice.7.html
34#[inline]
35#[doc(alias = "SIOCGIFINDEX")]
36pub fn name_to_index(fd: impl AsFd, if_name: &str) -> io::Result<u32> {
37 crate::backend::net::netdevice::name_to_index(fd, if_name)
38}
39
40/// `ioctl(fd, SIOCGIFNAME, ifreq)`—Returns the interface name for a given
41/// index.
42///
43/// See the [module-level documentation] for information about `fd` usage.
44///
45/// # References
46/// - [Linux]
47///
48/// [module-level documentation]: self
49/// [Linux]: https://man7.org/linux/man-pages/man7/netdevice.7.html
50#[inline]
51#[doc(alias = "SIOCGIFNAME")]
52#[cfg(feature = "alloc")]
53pub fn index_to_name(fd: impl AsFd, index: u32) -> io::Result<String> {
54 crate::backend::net::netdevice::index_to_name(fd, index)
55}
56
57#[cfg(test)]
58mod tests {
59 use crate::backend::net::netdevice::{index_to_name, name_to_index};
60 use crate::net::{AddressFamily, SocketFlags, SocketType};
61
62 #[test]
63 fn test_name_to_index() {
64 let fd = crate::net::socket_with(
65 AddressFamily::INET,
66 SocketType::DGRAM,
67 SocketFlags::CLOEXEC,
68 None,
69 )
70 .unwrap();
71
72 let loopback_index = std::fs::read_to_string("/sys/class/net/lo/ifindex")
73 .unwrap()
74 .as_str()
75 .split_at(1)
76 .0
77 .parse::<u32>()
78 .unwrap();
79 assert_eq!(Ok(loopback_index), name_to_index(fd, "lo"));
80 }
81
82 #[test]
83 #[cfg(feature = "alloc")]
84 fn test_index_to_name() {
85 let fd = crate::net::socket_with(
86 AddressFamily::INET,
87 SocketType::DGRAM,
88 SocketFlags::CLOEXEC,
89 None,
90 )
91 .unwrap();
92
93 let loopback_index = std::fs::read_to_string("/sys/class/net/lo/ifindex")
94 .unwrap()
95 .as_str()
96 .split_at(1)
97 .0
98 .parse::<u32>()
99 .unwrap();
100 assert_eq!(Ok("lo".to_owned()), index_to_name(fd, loopback_index));
101 }
102}
103