How to make authentication by call to 8(800)?

Question

Asterisk

[upd] I do not deal with WiFi in hotels, I just gave this method as an example. I'm only interested in a technical solution, how to catch the caller's phone number with minimal effort on a linux server.

It is necessary to make this type of authentication:
1) The user enters a phone number (on the web)
2) The user is asked to call the number 8(800)ххх-хх-хх
3) He calls.
4) Hooray, authentication was successful!
Such a scheme is often used in hotels to enter WiFi

[upd]


Everything is clear to me here, except for one thing: what software (as simple as possible) to take in order to receive and immediately reset a call on a Linux server and write information about the phone number to the database?

* Asterisk, FreePBX, Kamailio look rather cumbersome for this task, perhaps there are some simple solutions to the problem.
** saas can also be offered, but it is more priority to build a solution on your server.