/* TEST TEST TEST */
    static plist covert = NULL; // lista che contiene tutti i bit covert
    static int length_covert=0; // lunghezza lista covert
    int len;
    int exitCond = 0;
    int i = 0;
    int j = 0;
    struct timespec now,after;
    double difference = 0;
    double timing_interval = 1;
    char* covert_message;

    clock_gettime(CLOCK_MONOTONIC, &now);
    int fail_or_len = recvfrom(sock, (char *) data, MAX_UDP_PACKET_SIZE, 0, (struct sockaddr *)&addr, &addrlen);
    clock_gettime(CLOCK_MONOTONIC, &after);
    difference = ( ((double)after.tv_sec + 1.0e-9*after.tv_nsec) - ((double)now.tv_sec + 1.0e-9*now.tv_nsec) ) * 100 * 1000;
    //printf("D: %4f\n", difference);
    if(fail_or_len > 800) {

        difference = difference-timing_interval/2;
        printf("Difference: %4f\n", difference);
        int zeros=(int)(difference/timing_interval);
        if(difference < 0) // sto ancora inviando in covert mode
            insertCovert(&covert,zeros,&length_covert);

        covert_message = list_to_array(covert,length_covert+1);
        printf("covert_message[0]: %4d\n", covert_message[0]);
        covert_message = decodeCovert(covert_message);
    }

    if(covert_message)
       if(strcmp(covert_message, "") != 0)
          printf("Messaggio covert: %s\n",covert_message);

    /**/



/***** insertCovert ********/
void insertCovert(plist* l, int zeros, int* length) {
    int i;
    plist x = *l;
    /*
    if(x!=NULL) {
        while(x->next != NULL)
            x = x->next;
    } else {
        x = (plist)malloc(sizeof(list));
        x->next = (plist)malloc(sizeof(list));
        *l = x->next;
    }

    for (i = 0; i < zeros; i++) {
        if(x->next==NULL)
            x->next = (plist)malloc(sizeof(list));
        x = x->next;
        x->value = 0;
        x->next = NULL;
    }
    */
    if (x == NULL) {
        x = (plist)malloc(sizeof(list));
        x->value=0;
        x->next=NULL;
        zeros--;
        *l = x;
    }

    while(x->next != NULL)
        x = x->next;

    for (i = 0; i < zeros; i++) {
        x->next = (plist)malloc(sizeof(list));
        x = x->next;
        x->value = 0;
        x->next = NULL;
    }

    x->next=(plist)malloc(sizeof(list));
    x = x->next;
    x->value = 1;
    x->next = NULL;

    *length = *length + zeros + 1;
}