Wi-Fi scan for Apple OS X (maybe works for iOS too)

wifi_scan.m

//
//  wifi_scan.m
//  WifiDump
//
//  Created by Shawn Cicoria on 12/22/16.
//  Copyright © 2016 CedarLogic, LLC. All rights reserved.
//


/* The official example for CoreWLAN is now obsolete,
 so here's a small command-line example that works with Xcode 6 and Yosemite.
 It only demonstrates how to get basic wi-fi connection properties and scan.
 Enjoy!
 [email protected]  01-Mar-2015
 */

#import <Foundation/Foundation.h>
#import <CoreWLAN/CoreWLAN.h>
#include <stdio.h>

char const *phyModeName( enum CWPHYMode n )
{
  switch( (int)n ) {
    case kCWPHYModeNone: return "none";
    case kCWPHYMode11n: return "802.11n";
    case kCWPHYMode11a: return "802.11a";
    case kCWPHYMode11ac: return "802.11ac";
    case kCWPHYMode11g: return "802.11g";
    case kCWPHYMode11b: return "802.11b";
    default: return "other/unknown";
      
  }
}

char const *intfModeName( enum CWInterfaceMode m )
{
  switch( (int)m ) {
    case kCWInterfaceModeNone: return "none";
    case kCWInterfaceModeStation: return "STA";
    case kCWInterfaceModeIBSS: return "ADHOC";
    case kCWInterfaceModeHostAP: return "AP";
    default: return "unknown";
  }
}

// Enumerate available wi-fi interfaces and print:
void enumWifiInterfaces()
{
  NSArray *aif = CWWiFiClient.interfaceNames;
  for ( NSString *s in aif)  {
    NSLog(@"Ifname: %@\n", s);
  }
}

//  Convert NSstring to a "normal C" string, fast and dirty
char const * toCstr(NSString *ns ) {
  return [ns cStringUsingEncoding:[NSString defaultCStringEncoding]];
}

///////////
// - Register as CoreWLAN client
// - get some connection properties
// - Scan and display some neigbor info
//////////
int wlanTest()
{
  CWWiFiClient *wfc = CWWiFiClient.sharedWiFiClient;
  //NSLog(@"client: %@\n", wfc);
  if ( !wfc ) {
    return 1;
  }
  
  CWInterface *wif = wfc.interface; // get default interface
  if (!wif) {
    return 1;
  }
  
  printf("Default wifi interface name: %s\n", toCstr(wif.interfaceName));
  
  CWPHYMode phyMode = wif.activePHYMode;
  printf("Phy mode = %s\n", phyModeName((int)phyMode) );
  printf("Intf. mode: %s\n", intfModeName(wif.interfaceMode));
  
  if ( wif.interfaceMode == kCWInterfaceModeStation ) {
    printf("RSSI with assoc. AP (dBm)=%d ", (int)wif.rssiValue);  // returns 0 if not assoc. or error
    printf("Noise (dBm)=%d\n", (int)wif.noiseMeasurement);        // -"-"-
  }
  
  printf("Scanning...\n");
  NSError *err;
  // Nil for SSID does normal passive scan
  // Scan returns NSset of CWNetwork*
  NSSet *scanset = [wif scanForNetworksWithSSID:Nil error:&err];
  if (err) {
    printf("Scan failed, err=%ld\n", err.code);
    return 1;
  }
  
  printf("Scan found %d networks\n", (int)scanset.count);
  if ( scanset.count != 0 ) {
    int ix = 1;
    for (CWNetwork * nw in scanset)
    {
      printf(" %d. ssid=%s  Bssid=%s rssi=%ld on channel %ld\n", ix++, toCstr([nw ssid]), toCstr([nw bssid] ), (long)[nw rssiValue], (long)[[nw wlanChannel] channelNumber]);
    }
  }
  
  return 0;
}


int main(int argc, const char * argv[])
{
  @autoreleasepool {
    printf("Wi-Fi scan test on the default adapter\n");
    wlanTest();
  }
  return 0;
}