ESP8266 sniffer code help getting more information

Hello ,

I'm using this code

https://www.hackster.io/rayburne/esp8266-mini-sniff-f6b93a

which is working ,
but now I want to make it "work" for me
and I'm trying to understand the function.h code

I want to do something like Friend Detector within this code
so when it found a known MAC - it will light a led (for example)

and I can't see to understand how to save the MAC of data I'm getting
what is the function that get ,and how do i save it
Does someone know?

this is the main code :

// by Ray Burnette 20161013 compiled on Linux 16.3 using Arduino 1.6.12

#include <ESP8266WiFi.h>
#include "functions.h"

#define disable 0
#define enable  1
// uint8_t channel = 1;
unsigned int channel = 1;

void setup() {
  Serial.begin(57600);
  Serial.printf("\n\nSDK version:%s\n\r", system_get_sdk_version());
  Serial.println(F("ESP8266 mini-sniff by Ray Burnette http://www.hackster.io/rayburne/projects"));
  Serial.println(F("Type:   /-------MAC------/-----WiFi Access Point SSID-----/  /----MAC---/  Chnl  RSSI"));

  wifi_set_opmode(STATION_MODE);            // Promiscuous works only with station mode
  wifi_set_channel(channel);
  wifi_promiscuous_enable(disable);
  wifi_set_promiscuous_rx_cb(promisc_cb);   // Set up promiscuous callback
  wifi_promiscuous_enable(enable);

#define LIST_SIZE 3 

  uint8_t friendmac[LIST_SIZE][12] = { 
  {0x11, 0x11, 0x11, 0x11, 0x11, 0x11} 
 ,{0x22, 0x22, 0x22, 0x22, 0x22, 0x22}
 ,{0xd0 , 0x11 , 0x56 , 0xb0 , 0xba , 0x9b} 
 }; 

 String friendname[LIST_SIZE] = { 
  "Iphone 1 " 
 ,"Friend 2"
 , "Samsung A8" 
 }; 
}

void loop() {
  channel = 1;
  wifi_set_channel(channel);
  while (true) {
    nothing_new++;                          // Array is not finite, check bounds and adjust if required
    if (nothing_new > 200) {
      nothing_new = 0;
      channel++;
      if (channel == 15) break;             // Only scan channels 1 to 14
      wifi_set_channel(channel);
    }
    delay(1);  // critical processing timeslice for NONOS SDK! No delay(0) yield()
    // Press keyboard ENTER in console with NL active to repaint the screen
    if ((Serial.available() > 0) && (Serial.read() == '\n')) {
      Serial.println("\n-------------------------------------------------------------------------------------\n");
      for (int u = 0; u < clients_known_count; u++) print_client(clients_known[u]);
      for (int u = 0; u < aps_known_count; u++) print_beacon(aps_known[u]);
      Serial.println("\n-------------------------------------------------------------------------------------\n");
    }
  }
}

this is the function.h

// This-->tab == "functions.h"

// Expose Espressif SDK functionality
extern "C" {
#include "user_interface.h"clients_known
  typedef void (*freedom_outside_cb_t)(uint8 status);
  int  wifi_register_send_pkt_freedom_cb(freedom_outside_cb_t cb);
  void wifi_unregister_send_pkt_freedom_cb(void);
  int  wifi_send_pkt_freedom(uint8 *buf, int len, bool sys_seq);
}

#include <ESP8266WiFi.h>
#include "./structures.h"

#define MAX_APS_TRACKED 100
#define MAX_CLIENTS_TRACKED 200

beaconinfo aps_known[MAX_APS_TRACKED];                    // Array to save MACs of known APs
int aps_known_count = 0;                                  // Number of known APs
int nothing_new = 0;
clientinfo clients_known[MAX_CLIENTS_TRACKED];            // Array to save MACs of known CLIENTs
int clients_known_count = 0;                              // Number of known CLIENTs



int register_beacon(beaconinfo beacon)
{
  int known = 0;   // Clear known flag
  for (int u = 0; u < aps_known_count; u++)
  {
    if (! memcmp(aps_known[u].bssid, beacon.bssid, ETH_MAC_LEN)) {
      known = 1;
      break;
    }   // AP known => Set known flag
  }
  if (! known)  // AP is NEW, copy MAC to array and return it
  {
    memcpy(&aps_known[aps_known_count], &beacon, sizeof(beacon));
    aps_known_count++;

    if ((unsigned int) aps_known_count >=
        sizeof (aps_known) / sizeof (aps_known[0]) ) {
      Serial.printf("exceeded max aps_known\n");
      aps_known_count = 0;
    }
  }
  return known;
}

int register_client(clientinfo ci)
{
  int known = 0;   // Clear known flag
  for (int u = 0; u < clients_known_count; u++)
  {
    if (! memcmp(clients_known[u].station, ci.station, ETH_MAC_LEN)) {
      known = 1;
      break;
    }
  }
  if (! known)
  {
    memcpy(&clients_known[clients_known_count], &ci, sizeof(ci));
    clients_known_count++;

    if ((unsigned int) clients_known_count >=
        sizeof (clients_known) / sizeof (clients_known[0]) ) {
      Serial.printf("exceeded max clients_known\n");
      clients_known_count = 0;
    }
  }
  return known;
}

void print_beacon(beaconinfo beacon)
{
  if (beacon.err != 0) {
    //Serial.printf("BEACON ERR: (%d)  ", beacon.err);
  } else {
    Serial.printf("BEACON: <=============== [%32s]  ", beacon.ssid);
    for (int i = 0; i < 6; i++) Serial.printf("%02x", beacon.bssid[i]);
    Serial.printf("   %2d", beacon.channel);
    Serial.printf("   %4d\r\n", beacon.rssi);
  }
}

void print_client(clientinfo ci)
{
  int u = 0;
  int known = 0;   // Clear known flag
  if (ci.err != 0) {
    // nothing
  } else {
    Serial.printf("DEVICE: ");
    for (int i = 0; i < 6; i++) Serial.printf("%02x", ci.station[i]);
    Serial.printf(" ==> ");

    for (u = 0; u < aps_known_count; u++)
    {
      if (! memcmp(aps_known[u].bssid, ci.bssid, ETH_MAC_LEN)) {
        Serial.printf("[%32s]", aps_known[u].ssid);
        known = 1;     // AP known => Set known flag
        break;
      }
    }

    if (! known)  {
      Serial.printf("   Unknown/Malformed packet \r\n");
      //  for (int i = 0; i < 6; i++) Serial.printf("%02x", ci.bssid[i]);
    } else {
      Serial.printf("%2s", " ");
      for (int i = 0; i < 6; i++) Serial.printf("%02x", ci.ap[i]);
      Serial.printf("  %3d", aps_known[u].channel);
      Serial.printf("   %4d\r\n", ci.rssi);
    }
  }
}

void promisc_cb(uint8_t *buf, uint16_t len)
{
  int i = 0;
  uint16_t seq_n_new = 0;
  if (len == 12) {
    struct RxControl *sniffer = (struct RxControl*) buf;
  } else if (len == 128) {
    struct sniffer_buf2 *sniffer = (struct sniffer_buf2*) buf;
    struct beaconinfo beacon = parse_beacon(sniffer->buf, 112, sniffer->rx_ctrl.rssi);
    if (register_beacon(beacon) == 0) {
      print_beacon(beacon);
      nothing_new = 0;
    }
  } else {
    struct sniffer_buf *sniffer = (struct sniffer_buf*) buf;
    //Is data or QOS?
    if ((sniffer->buf[0] == 0x08) || (sniffer->buf[0] == 0x88)) {
      struct clientinfo ci = parse_data(sniffer->buf, 36, sniffer->rx_ctrl.rssi, sniffer->rx_ctrl.channel);
      if (memcmp(ci.bssid, ci.station, ETH_MAC_LEN)) {
        if (register_client(ci) == 0) {
          print_client(ci);
          nothing_new = 0;
        }
      }
    }
  }
}

I have tried to use this line :

clients_known[u].station

but it doesn't work

Thanks ,