Host ID.

[Jung-uk Kim]

On Sunday 08 April 2007 11:13 am, Pawel Jakub Dawidek wrote:
> On Sun, Apr 08, 2007 at 10:04:16PM +0900, gnn at freebsd.org wrote:
> > I noted that someone mentioned using a network based ID.  Since
> > EUI-64 are unique I would suspect they would be the best source
> > for this on systems that don't naturally have a hostid concept. 
> > See Appendix A of RFC 2373 for how to create an EUI-64 Interface
> > Identifier.
> >
> > The only problem with this approach that I see is that if you
> > remove that interface (that is it was on a card not on your
> > motherboard) then it goes away.  Perhaps generating this and
> > storing it, no matter what the future network configuration of
> > the system is, is the right way to go.
>
> So why not generate it and be done with it? And what if you move
> your card to another box were you're planning to install new
> system?

Actually uuidgen(2) uses uuid(3) and uuid(3) generates UUID version 1 
string, i.e., it is based on timestamp and MAC address already. :-)

http://en.wikipedia.org/wiki/UUID
http://tools.ietf.org/html/rfc4122

Unfortunately some SMBIOS contain broken UUIDs, e.g., they don't 
conform RFC4122.  If it does not conform RFC4122, then we should 
reject it.  If it does (i.e., format, version number, etc), then use 
it instead of faking one.

BTW, uuid(3) needs some improvement, i.e., we need to implement 
version 2 to 5.  See Appendix A of RFC4122 for sample 
implementations.

> I'd really like to make it simple and consistent on all archs, so
> one knows exactly what to expect.

Agreed.  But I also agree with imp, i.e., we have to utilize hardware 
UUID if it is available and valid for the platform.

Jung-uk Kim