How can you handle the opening of a WebSocket(socket.io), even before the opening?

Question

Node.js

As I understand it, it opens like this:
https://yadi.sk/i/0rvevjKf3GEhL2
1) First, an ajax request is sent.
2) After that, WS opens.
I want to make protection by ip so that it would be impossible to create 2 websockets from one ip.
Done like this:
io.use( and handler function)
but at this point ws is already open.
Is there a means in socket io to set the number of ws from one ip or to process the first ajax request?

Answer 1

Haven't heard of nat at all? Now a lot of users on the network are sitting from 1 address.