As of r24147, it is possible for callers to use libgssrpc with IPv6
sockets provided that they:
* Create and connect/bind their own sockets.
* Only use TCP.
* Do not query the addresses of client or server objects.
That's enough to get kadmin working, as noted in #6746. There's no
fundamental reason why UDP could not also be supported, but allowing the
portmapper to be used might be difficult.
As I understand it, our libgssrpc is based on Sun's (now Oracle's) ONC
RPC. That API was updated to work with non-IPv4 transports and is now
called TIRPC. TIRPC has been incorporated into libc on the *BSD
platforms and has also been ported to Linux (though not incorporated
into glibc).
Our current understanding is that TIRPC code has been made available
under two licenses: the SISSL and (via OpenSolaris) the CDDL. Neither
is believed to be GPL-compatible. We are not aware of any
implementations of TIRPC which are not derived from Sun/Oracle's code.
We have made a request for the relevant parts of OpenSolaris to be
relicensed under a BSD-like license so we might adapt it for the krb5
tree.