Captive Portal and SIP2

[Crusher Bob]

I work for a public library. The library maintains a wireless network that library patrons can log on to. The login is supposed to require their library card number and PIN, which is submitted to the state library web site for verification.

The setup we are using is a machine with two network cards running pfsense, with one card plugged into a wireless router, and the other card plugged into the library network, which has an Internet connection. The pfsense captive portal is setup to redirect users to a part of the state library website where they can enter their card number and PIN.

One of the machines at our branch library has suffered a hardware fault and needed to be replaced.

I muddled through getting an old machine of out a closet, getting a stand alone network card installed in it, and the latest version of pfsense installed.

But... it turns out that pfsense doesn't natively support the 'SIP2' protocol that the state library website is setup to accept. We were apparently using a modified version of pfsense (1.2.2). It looks like the modification we are using is here:
github.com/nilesingalls/pfsense
on github. But seems to have only been updated to pfsense 2.2.X

My technical skills are limited. Can someone who knows what they are doing please take a look at the github code. Can this code be integrated with the latest version of pfsense? If so, can I please get directions on how to compile an installable version of pfsense with this code added? If not, same question for a version of 2.2.X that this code can be integrated with.

Other comments:
The 'SIP2' protocol I'm talking about is the 'Standard Interchange Protocol' apparently used by many libraries, not the 'Session Initiation Protocol' used for video chatting.

Some comments by the original developer are available here:
forum.netgate.com/topic/16184/question-on-approach-modifying-captive-portal-adding-authentication-method/2