code: func (v *veth) attach(n *configs.Network) (err error) {
  	bridge, err := net.InterfaceByName(n.Bridge)
  	if err != nil {
  		return err
  	}
  	host, err := net.InterfaceByName(n.HostInterfaceName)
  	if err != nil {
  		return err
  	}
  	if err := netlink.AddToBridge(host, bridge); err != nil {
  		return err
  	}
  	if err := netlink.NetworkSetMTU(host, n.Mtu); err != nil {
  		return err
  	}
  	if n.HairpinMode {
  		if err := netlink.SetHairpinMode(host, true); err != nil {
  			return err
  		}
  	}
  	if err := netlink.NetworkLinkUp(host); err != nil {
  		return err
  	}
  
  	return nil
  }
docs: // attach a container network interface to an external network