#include <stdio.h>

#define OPEN_PORT_FUNCTION print_open
#define CLOSE_PORT_FUNCTION print_close
#define CONNECT_PORT_FUNCTION print_connect

void handle_open_port(unsigned int x, void *(*open_port)(unsigned int port));
void handle_close_port(unsigned int x, void *(*close_port)(unsigned int port));
void handle_connect_to_port(unsigned int x, void *(*connect_to_port)(unsigned int port));

void print_open(unsigned int x);
void print_close(unsigned int x);
void print_connect(unsigned int x);

#define PREVIOUS_FRAME(x, y) *(unsigned int *)(x + y)

long gap_between_x = 0;

void kernel_recursion(unsigned int x) {
  long current_offset = gap_between_x - (long)(char *)&x;
  gap_between_x = (long)(char *)&x;

  unsigned int previous_x = PREVIOUS_FRAME((char *)&x, current_offset);

  if (x < previous_x) {
    handle_open_port(x, (void*(*)(unsigned int))OPEN_PORT_FUNCTION);
    ++x;
    kernel_recursion(previous_x);
    --x;
    handle_close_port(x, (void*(*)(unsigned int))CLOSE_PORT_FUNCTION);
  } else if (previous_x < x) {
    handle_open_port(previous_x, (void*(*)(unsigned int))OPEN_PORT_FUNCTION);
    kernel_recursion(previous_x + 1);
    --x;
    handle_close_port(previous_x, (void*(*)(unsigned int))CLOSE_PORT_FUNCTION);
  } else {
    handle_open_port(previous_x, (void*(*)(unsigned int))OPEN_PORT_FUNCTION);
    handle_close_port(previous_x, (void*(*)(unsigned int))CLOSE_PORT_FUNCTION);
  }
}
void kernel(unsigned int x) {
  gap_between_x = (long)&x;
  kernel_recursion(0);
}

int main() { kernel(22000); }

void handle_open_port(unsigned int x, void *(*open_port)(unsigned int port)) {
  open_port(x);
}
void handle_close_port(unsigned int x, void *(*close_port)(unsigned int port)) {
  handle_connect_to_port(x, (void*(*)(unsigned int))CONNECT_PORT_FUNCTION);
  close_port(x);
}
void handle_connect_to_port(unsigned int x,
                            void *(*connect_to_port)(unsigned int port)) {
  connect_to_port(x);
}

void print_open(unsigned int x) { printf("Opened port %u\n", x); }
void print_close(unsigned int x) { printf("Closed port %u\n", x); }
void print_connect(unsigned int x) { printf("Connected port %u\n", x); }