can.h

#pragma once

struct CanMessage {
    uint8_t size;

    uint8_t *data;

    uint16_t id;

    CanMessage(uint8_t size, uint8_t *data, uint16_t id): size(size), data(data), id(id){}
};

class CAN{

protected:
    void (*upper_level)(CanMessage &data);

public:
    virtual void SendMessage(CanMessage &message) = 0;

    void SetUpperLevel(void (*handler)(CanMessage &data)) {
        this->upper_level = handler;
    }
};