Global (non _KERNEL) place for sockaddr_union?

[Max Laier]

On Monday 20 September 2004 04:28, Brooks Davis wrote:
> On Mon, Sep 20, 2004 at 02:50:40AM +0200, Max Laier wrote:
> > Hi,
> >
> > http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/71836 is the symptom. Now
> > I am looking for a clean solution to it. What is needed is an include
> > file that defines union sockaddr_union in a way that is useable from
> > kernel and userland. Historically it seems that this union first apeared
> > in context of ipsec within the kernel. pf has adopted it, but uses it in
> > the userland as well. I am sure that it can be usefull in a lot of places
> > that have to deal with/store different address formats.
> >
> > My question now is, what would be a good place to define this? Are there
> > any fromal standarts that might define it already? (Couldn't find
> > anything) Is there anything else that I must consider?
> >
> > At some point I though netinet/in.h might be a good place, but that'd
> > require inclusion of sys/socket.h, which certainly is not a good
> > solution.
> >
> > Opinions? Ideas?
> >
> > > #include <sys/socket.h>
> > > #include <netinet/in.h>
> > >
> > > union sockaddr_union {
> > >  struct sockaddr   sa;
> > >  struct sockaddr_in  sin;
> > >  struct sockaddr_in6  sin6;
> > >  struct sockaddr_storage __su_pad;  /* maybe not a bad idea */
> > > };
>
> I don't see an elegant solution.  Stuffing it off in its own file may
> be the best thing if you're going to use it.  Overall, I'd say it's bad
> idea that PF be better off without.  It appears to save a few casts,
> but nothing worth the pain of generalizing the declaration.
>
> -- Brooks

First of all, the padding is bogus as sin6 is big enough. Especially since one 
point here is to save space. I was a bit confused there, sorry. Especially 
since this is an important point: In pf this union is uses to - for example - 
store address information in tables. It allows to store IPv4 and IPv6 
addresses in the same table without creating overhead in the memory footprint 
or having to deal with different objects for every address type. The fewer 
casts are just an additional benefit.

Maybe you are right and a new header is the easiest way out. Moving this out 
of under _KERNEL would require all includer of netipsec/keydb.h to include 
sys/socket.h and netinet/in.h. As I was saying, I don't have a good idea 
either. The only thing that came to my mind just now is to add a protecting 
define and #ifdef around the two places that define it. But I have no idea 
how clean (in terms of style) such a solution is.

-- 
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