network_linux.go
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
}
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
}
// attach a container network interface to an external network