get router MACAddress

gistfile1.m

- (NSString *)routerMACAddress {
    NSMutableString *MACAddress = [NSMutableString string];
    SCDynamicStoreRef theDynamicStore = SCDynamicStoreCreate(nil, CFSTR("FindCurrentInterfaceAndIP"), nil, nil);
    CFDictionaryRef returnedPList = SCDynamicStoreCopyValue(theDynamicStore, CFSTR("State:/Network/Global/IPv4"));
    CFRelease(theDynamicStore);
    
    if ([(__bridge NSDictionary *)returnedPList valueForKey:@"Router"] != nil) {
        NSTask *arpTask = [[NSTask alloc] init];
        NSPipe *newPipe = [NSPipe pipe];
        NSFileHandle *readHandle = [newPipe fileHandleForReading];
        [arpTask setStandardOutput:newPipe];
        [arpTask setLaunchPath:@"/usr/sbin/arp"];
        [arpTask setArguments:[NSArray arrayWithObject:[(__bridge NSDictionary *)returnedPList valueForKey:@"Router"]]];
        [arpTask launch];
        [arpTask waitUntilExit];
        NSString *outputString = [[NSString alloc] initWithData:[readHandle availableData] encoding:NSUTF8StringEncoding];

        int i=0;
        int spaceCount = 0;
        for (i=0; i<[outputString length]; i++) {
            if ([outputString characterAtIndex:i] == ' ') {
                spaceCount++;
            };
            if (spaceCount == 3 && [outputString characterAtIndex:i] != ' ') {
                [MACAddress appendFormat:@"%c",[outputString characterAtIndex:i]];
            };
        };
    };
    
    return MACAddress;
}

- (NSString *)defaultRouter {
    SCDynamicStoreRef ds = SCDynamicStoreCreate(kCFAllocatorDefault, CFSTR("myapp"), NULL, NULL);
    CFDictionaryRef dr = SCDynamicStoreCopyValue(ds, CFSTR("State:/Network/Global/IPv4"));
    CFStringRef router = CFDictionaryGetValue(dr, CFSTR("Router"));
    NSString *routerString = [NSString stringWithString:(__bridge NSString *)router];
    CFRelease(dr);
    CFRelease(ds);
    return routerString;
}