How to make wifi hotspot with captive portal?

Question

WiFi

Hello, just a couple of hours I had to study this direction, so I can write nonsense.
Task:
1. A client enters a cafe and selects our access point.
2. The client is trying to access the Internet.
3. He is redirected to the page through which he must log in, let 's say mycafe/auth-wifi.php where the client logs in no matter what, even through the social. network.
4. If you are logged in, you can use the Internet as much as you like.
Tell me how to implement this, if not difficult, describe it step by step so it's easiest to understand.

Answer 1

As I understand it, it is necessary:
​​1. A computer with two network cards
2. eth0 - Internet, eth1 - modem output with wi-fi
3. Install the Captive portal server, I stopped at PacketFence for now, which will pass traffic through itself and redirect unauthorized users to /auth-wifi.php
4. FreeRADIUS for authorization, let's say for storing information about users in MySql.
5. Apache + PHP
Who has any thoughts? Or this topic is so not popular that no one is interested (