@0xcb50be3531badf53;

using Cxx = import "/capnp/c++.capnp";
$Cxx.namespace("vanetza::rpc");

interface LinkLayer
{
    struct Frame
    {
        sourceAddress @0 :Data;
        destinationAddress @1 :Data;
        payload @2 :Data;
    }

    struct WlanParameters
    {
        # Parameters for WLAN devices in OCB mode (IEEE 802.11 p and bd)
        priority @0 :UInt8;     # 802.1 user priority (0-7)
        power @1 :Int16;        # dBm scaled by 8
        datarate @2 :UInt16;    # Mbps scaled by 2 (500kbps steps)
    }

    struct Cv2xParameters
    {
        # Parameters for C-V2X devices (LTE-V2X and 5G-V2X)
        priority @0 :UInt8;     # PPPP (0-7)
        power @1 :Int16;        # dBm scaled by 8
    }

    struct TxParameters
    {
        union
        {
            unspecified @0 :Void;
            wlan @1 :WlanParameters;
            cv2x @2 :Cv2xParameters;
        }
    }

    struct RxParameters
    {
        union
        {
            unspecified @0 :Void;
            wlan @1 :WlanParameters;
            cv2x @2 :Cv2xParameters;
        }

        timestamp :union
        {
            none @3 :Void;
            hardware @4 :UInt64;
            # time stamp accurately generated by hardware
            software @5 :UInt64;
            # time stamp added by software (slightly inaccurate)
        }
    }

    interface DataListener
    {
        onDataIndication @0 (frame: Frame, rxParams :RxParameters);
    }

    interface CbrListener
    {
        onCbrReport @0 (cbr :ChannelBusyRatio);
    }

    struct ChannelBusyRatio
    {
        busy @0 :UInt16;        # number of samples sensed as busy
        samples @1 :UInt16;     # total number of samples in measurement interval
    }

    enum ErrorCode
    {
        ok @0;
        invalidArgument @1;
        unsupported @2;
        internalError @3;
    }

    identify @0 () -> (id :UInt64, version :UInt32, info :Text);
    # lookup identify of link layer device 

    transmitData @1 (frame :Frame, txParams :TxParameters) -> (error :ErrorCode, message :Text);
    # request transmission of a data frame

    subscribeData @2 (listener :DataListener);
    # subscribe to received data frames

    subscribeCbr @3 (listener :CbrListener);
    # subscribe to channel busy ratio reports

    setSourceAddress @4 (address :Data) -> (error :ErrorCode);
    # set (own) source address of link layer (for ACKs)
}