Browser logged user in dynamics crm

Dear all,

we have our organization CRM and we authenticate by IFD.

We are implementing our custom WebApi 2 in c#.

Those webApi will be called using javascript/jquery in dynamics crm.

How it's possibile to identify in our custom webapis (server side) the dynamics crm user logged in browser that are calling ?

We want to implement something like the HTTPGET /WhoAmI API avaliable in CRM.

Thanks in advance!

Domenico Casalino