OS X Tethering Check

osx-tethering-check

#import <CoreWLAN/CoreWLAN.h>
#import <SystemConfiguration/SystemConfiguration.h>

extern CFStringRef _SCNetworkInterfaceGetIOPath(SCNetworkInterfaceRef interface);

@interface CWNetwork (Voodoo)
- (NSDictionary*) scanRecord;
@end


- (BOOL) tetheringOverWifiActive
{
    CWInterface* interface = [CWInterface interface];
    
    NSSet* networks = [interface scanForNetworksWithSSID:nil error:nil];
    for(CWNetwork* network in networks)
    {
        if ([interface.ssid isEqualToString:network.ssid]) {
            
            NSDictionary* scanRecord = [network scanRecord];
            BOOL networkCreatedByIOSDevice = (scanRecord[@"IOS_IE"] != nil);
            return networkCreatedByIOSDevice;
        }
    }
    return NO;
}

- (BOOL) tetheringOverUSBActive
{
    NSArray* interfaces = (__bridge NSArray*)SCNetworkInterfaceCopyAll();
    for(id i in interfaces) {
        SCNetworkInterfaceRef interface = (__bridge SCNetworkInterfaceRef)i;
        
        NSString* type = (__bridge NSString*)SCNetworkInterfaceGetInterfaceType(interface);
        NSString* address = (__bridge NSString*)_SCNetworkInterfaceGetIOPath(interface);
        if ([type isEqualToString:@"Ethernet"] && [address rangeOfString:@"AppleUSBEthernetHost"].location != NSNotFound && [address rangeOfString:@"iPhone"].location != NSNotFound) {
            return YES;
        }
    }
    return NO;
}

You can't ship this code in the App Store though as you need private methods.