Thanks for your response. We are able to get the information of web page accessing device (Laptop/PC) in "/proc/net/tcp" file, with that we can limit the access to the web interface, but the problem is that it will clear the device information when the webpage is static and it will not update the file immediately when the browser is closed (Takes around a min to clear the entries in the file).
In our web page the user name is always fixed and user can login to the router using password. Upon logging in the user can change the Wi-Fi setting through web page. If another user login to router from another system and both the user try to change the Wi-Fi setting then it will be a problem. To avoid this situation we need to limit the login to single user (If the first user logout then the 2nd user can login).
Also if we login to the web page and user disconnects from the existing wi-fi and after few minutes if the user again connects back to the same wi-fi router and refreshes the page, the web page is again loaded. In the above condition we need the web page to be redirected to login page.
How can we handle the above 2 condition.