How can I get the list of all active network interfaces programmatically?

My objective is to determine the IP address for Ethernet on a device. But assuming that there are connections like WiFi and USB Ethernet, is there a particular way just to get the Ethernet IP ? On a shell I would do networksetup -listallhardwareports which would give me a mapping of Hardware Port to Device. From that I would grep the device for Hardware Port: Ethernet and then use ifaddr struct to get my IP. I know the ifaddr part, please suggest how to do the first part programmatically. Also, is there an alternative approach ?