Mac OS X：如何获取所有可用WiFi网络的MAC地址？

I need to get the MAC addresses of all WIFI networks which are founded by the WIFI module. After collecting them, I need to compare them with another MAC address, which is static and saved in the app. My goal is it, to only allow to use the app, if you are close enough at the router. I need to get the MAC addresses of all WIFI net