if err != nil {
		return nil, err
	}
	switch network {
	case "ip", "ip4", "ip6":
	default:
		return nil, UnknownNetworkError(sd.network)
	}
	ctrlCtxFn := sd.Dialer.ControlContext
	if ctrlCtxFn == nil && sd.Dialer.Control != nil {
		ctrlCtxFn = func(ctx context.Context, network, address string, c syscall.RawConn) error {
			return sd.Dialer.Control(network, address, c)
		}
	}

	return sd.doDialTCPProto(ctx, laddr, raddr, 0)
}

func (sd *sysDialer) doDialTCPProto(ctx context.Context, laddr, raddr *TCPAddr, proto int) (*TCPConn, error) {
	ctrlCtxFn := sd.Dialer.ControlContext
	if ctrlCtxFn == nil && sd.Dialer.Control != nil {
		ctrlCtxFn = func(ctx context.Context, network, address string, c syscall.RawConn) error {
			return sd.Dialer.Control(network, address, c)
		}
	}

		sa = &syscall.SockaddrUnix{Name: addr.Name}
	}
	return c.fd.writeMsg(b, oob, sa)
}

func (sd *sysDialer) dialUnix(ctx context.Context, laddr, raddr *UnixAddr) (*UnixConn, error) {
	ctrlCtxFn := sd.Dialer.ControlContext
	if ctrlCtxFn == nil && sd.Dialer.Control != nil {
		ctrlCtxFn = func(ctx context.Context, network, address string, c syscall.RawConn) error {
			return sd.Dialer.Control(network, address, c)
		}
	}

		return 0, 0, &AddrError{Err: "invalid address family", Addr: addr.Addr().String()}
	}
}

func (sd *sysDialer) dialUDP(ctx context.Context, laddr, raddr *UDPAddr) (*UDPConn, error) {
	ctrlCtxFn := sd.Dialer.ControlContext
	if ctrlCtxFn == nil && sd.Dialer.Control != nil {
		ctrlCtxFn = func(ctx context.Context, network, address string, c syscall.RawConn) error {
			return sd.Dialer.Control(network, address, c)
		}
	}