Our main task is to configure smart devices for networking. When the phone connects to the AP hotspot emitted by the smart device, it needs to obtain the IP address of the smart device, and then send a subnet broadcast like xx.xx.xx.255 based on the IP segment in order to complete the networking configuration. Additionally, can valid Wi-Fi interface be obtained through function CNCopySupportedInterfaces()?

When a phone connects to a device's AP hotspot, the IP address it obtains is in the same network segment as the device. For example, if the current IP address of the phone is 192.168.1.100 and the device's IP address is 192.168.1.x, the phone sends a subnet broadcast to 192.168.1.255. The device will capture this UDP packet and use the information in the packet to connect to the router.

Also, this would all be a lot easier if your accessory supported Bonjour [1]. I'm sorry, but our accessory does not support Bonjour. the easiest way to avoid problems in this space is to send that broadcast on all Ethernet-like interfaces The prerequisite for sending a subnet broadcast is that I already know the IP address of the accessory, If I fail to retrieve the IP address of the en0 network interface, can I retrieve the IP addresses of all IPv4 network interfaces and then send a subnet broadcast?