Method set_mac_addr

net_util/src/tap.rs:366–393

Set mac addr for tap interface.

(&self, addr: MacAddr)

    /// Set mac addr for tap interface.
    pub fn set_mac_addr(&self, addr: MacAddr) -> Result<()> {
        // Checking if the mac address already matches the desired one
        // is useful to avoid making the "set ioctl" in the case where
        // the VMM is running without the privilege to do that.
        // In practice this comes from a reboot after the configuration
        // has been update with the kernel generated address.
        if self.get_mac_addr()? == addr {
            return Ok(());
        }

        let sock = create_unix_socket().map_err(Error::NetUtil)?;

        let mut ifreq = self.get_ifreq();

        // SAFETY: ioctl is safe. Called with a valid sock fd, and we check the return.
        unsafe { Self::ioctl_with_ref(&sock, libc::SIOCGIFHWADDR as c_ulong, &ifreq)? };

        // SAFETY: We only access one field of the ifru union
        unsafe {
            let ifru_hwaddr = &mut ifreq.ifr_ifru.ifru_hwaddr;
            for (i, v) in addr.get_bytes().iter().enumerate() {
                ifru_hwaddr.sa_data[i] = *v as c_char;
            }
        }

        // SAFETY: ioctl is safe. Called with a valid sock fd, and we check the return.
        unsafe { Self::ioctl_with_ref(&sock, libc::SIOCSIFHWADDR as c_ulong, &ifreq) }
    }

    /// Get mac addr for tap interface.
    pub fn get_mac_addr(&self) -> Result<MacAddr> {