The sockets API basically gives constant size data structures for
applications. I think we shouldn't break this design pattern. So
reserving a constant size extension field is ok, but variable size
structure (with the same name) is probably not a good idea.
Based on this discussion, it appears that the best way for future
proofing is to include a flag for getaddrinfo() in the hints
arguments that will result in sockaddr_hip_long structures instead
of sockaddr_hip. This way, applications get exactly what they want
and can store the HITs easily in their ACLs. I'd also remove the
extra space reserved space because it seems that it's not very
usable for future proofing as it is now.
Jeff, how do you feel about this or do you have a better suggestion?