I have portal login page which is developed by PHP and there is in another side free radius server run into Ubuntu machine the authentication occurred by MySQL database and every thing go fine when registered user trying to access the internet, he must insert username and password. after that this user will authenticate using a free radius server. now I want users to be able to log in using google apps where I can insert users there . I installed the google authenticator in ubuntu machine and it can generate QR code successfully , but how can I use it . in another word , I have g suit account and domain where I can insert the users who can log in to my captive portal . how can I do that and why I must use google authenticator because I don't know how can I using it in my system because google authenticator only generate QR code that means every body can log in to my portal and I don't want that I hope I explained my problem clearly
I hope I have understood your question correctly. Basically, you want to authenticate the user in Freeradius by using google authenticator.
You can't directly pass the QR code to Freeradius but you can do is once the user is authenticated using QR code on the web you can generate unique username and password based on QR code session and insert that values into radcheck and pass same username and password in the authentication request.
This is very generic approach to social media authentication on captive portal using Freeradius