lib/rust/wlantap-client/src/lib.rs

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#![deny(warnings)]

use {
    byteorder::{NativeEndian, WriteBytesExt},
    failure::Error,
    fdio::{fdio_sys, ioctl, make_ioctl},
    fidl::encoding::Encoder,
    fidl_fuchsia_wlan_tap as wlantap, fuchsia_async as fasync,
    fuchsia_zircon::{self as zx, AsHandleRef},
    std::{
        fs::{File, OpenOptions},
        mem,
        os::raw,
        path::Path,
    },
};

pub struct Wlantap {
    file: File,
}

impl Wlantap {
    pub fn open() -> Result<Wlantap, Error> {
        Ok(Wlantap {
            file: OpenOptions::new()
                .read(true)
                .write(true)
                .open(Path::new("/dev/test/wlantapctl"))?,
        })
    }

    pub fn create_phy(
        &self,
        mut config: wlantap::WlantapPhyConfig,
    ) -> Result<wlantap::WlantapPhyProxy, Error> {
        let (encoded_config, handles) = (&mut vec![], &mut vec![]);
        Encoder::encode(encoded_config, handles, &mut config)?;

        let (local, remote) = zx::Channel::create()?;

        let mut ioctl_in = vec![];
        ioctl_in.write_u32::<NativeEndian>(remote.raw_handle())?;
        ioctl_in.append(encoded_config);

        // Safe because the length of the buffer is computed from the length of a vector,
        // and ioctl() doesn't retain the buffer.
        unsafe {
            ioctl(
                &self.file,
                IOCTL_WLANTAP_CREATE_WLANPHY,
                ioctl_in.as_ptr() as *const std::os::raw::c_void,
                ioctl_in.len(),
                std::ptr::null_mut(),
                0,
            )?;
        }
        // Release ownership of the remote handle
        mem::forget(remote);
        Ok(wlantap::WlantapPhyProxy::new(fasync::Channel::from_channel(local)?))
    }
}

const IOCTL_WLANTAP_CREATE_WLANPHY: raw::c_int =
    make_ioctl!(fdio_sys::IOCTL_KIND_SET_HANDLE, fdio_sys::IOCTL_FAMILY_WLANTAP, 0);