[libvirt] Libvirt Xen daemon interaction in Red Hat Enterprise with virtualization

Hi, I am new to libvirt and I am trying to figure out that how libvert connects to Xend in Red Hat Enterprise with virtualization. I read a few posts but was not able to find this out. The eariler versions of Xen were using xen_session_login_with_password() function call to connect to Xen daemon but I am not able to find anything similar to this in libvirt. Please help me with the functions or the area of source code which are being used by libvirt to make the connections. Thanks Vaibhav