//! Low-level Linux network device access

//!

//! The methods in this module take a socket's file descriptor to communicate

//! with the kernel in their ioctl call:

//!  - glibc uses an `AF_UNIX`, `AF_INET`, or `AF_INET6` socket. The address

//!    family itself does not matter and glibc tries the next address family if

//!    socket creation with one fails.

//!  - Android (bionic) uses an `AF_INET` socket.

//!  - Both create the socket with `SOCK_DGRAM|SOCK_CLOEXEC` type/flag.

//!  - The [manual pages] specify that the ioctl calls “can be used on any

//!    socket's file descriptor regardless of the family or type”.

//!

//! # References

//!  - [Linux]

//!

//! [manual pages]: https://man7.org/linux/man-pages/man7/netdevice.7.html

//! [Linux]: https://man7.org/linux/man-pages/man7/netdevice.7.html

use crate::fd::AsFd;

use crate::io;

#[cfg(feature = "alloc")]

use alloc::string::String;

/// `ioctl(fd, SIOCGIFINDEX, ifreq)`—Returns the interface index for a given

/// name.

///

/// See the [module-level documentation] for information about `fd` usage.

///

/// # References

///  - [Linux]

///

/// [module-level documentation]: self

/// [Linux]: https://man7.org/linux/man-pages/man7/netdevice.7.html

#[inline]

#[doc(alias = "SIOCGIFINDEX")]

pub fn name_to_index<Fd: AsFd>(fd: Fd, if_name: &str) -> io::Result<u32> {

    crate::backend::net::netdevice::name_to_index(fd.as_fd(), if_name)

}

/// `ioctl(fd, SIOCGIFNAME, ifreq)`—Returns the interface name for a given

/// index.

///

/// See the [module-level documentation] for information about `fd` usage.

///

/// # References

///  - [Linux]

///

/// [module-level documentation]: self

/// [Linux]: https://man7.org/linux/man-pages/man7/netdevice.7.html

#[inline]

#[doc(alias = "SIOCGIFNAME")]

#[cfg(feature = "alloc")]

#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]

pub fn index_to_name<Fd: AsFd>(fd: Fd, index: u32) -> io::Result<String> {

    crate::backend::net::netdevice::index_to_name(fd.as_fd(), index)

}

#[cfg(test)]

mod tests {

    use crate::backend::net::netdevice::{index_to_name, name_to_index};

    use crate::fd::AsFd;

    use crate::net::{AddressFamily, SocketFlags, SocketType};

    #[test]

    fn test_name_to_index() {

        let fd = crate::net::socket_with(

            AddressFamily::INET,

            SocketType::DGRAM,

            SocketFlags::CLOEXEC,

            None,

        )

        .unwrap();

        let loopback_index = std::fs::read_to_string("/sys/class/net/lo/ifindex")

            .unwrap()

            .as_str()

            .split_at(1)

            .0

            .parse::<u32>()

            .unwrap();

        assert_eq!(Ok(loopback_index), name_to_index(fd.as_fd(), "lo"));

    }

    #[test]

    #[cfg(feature = "alloc")]

    fn test_index_to_name() {

        let fd = crate::net::socket_with(

            AddressFamily::INET,

            SocketType::DGRAM,

            SocketFlags::CLOEXEC,

            None,

        )

        .unwrap();

        let loopback_index = std::fs::read_to_string("/sys/class/net/lo/ifindex")

            .unwrap()

            .as_str()

            .split_at(1)

            .0

            .parse::<u32>()

            .unwrap();

        assert_eq!(

            Ok("lo".to_owned()),

            index_to_name(fd.as_fd(), loopback_index)

        );

    }

}