Re: [PATCH] 2.4.21-rc1: byteorder.h breaks with __STRICT_ANSI__ defined (trivial)

[Christoph Hellwig <hch@infradead.org>]

On Tue, May 06, 2003 at 10:07:14PM -0700, David S. Miller wrote:
> This doesn't even consider the case where the ipsec-tools copy of the
> headers becomes out of date with the kernel copy.  This isn't a
> theoretical issue, this problem is real.
> 
> For example, I just changed the values of a few SADB_EALG_* values in
> pfkeyv2.h.  Now ipsec-tools is effectively broken.  Oops, when will
> the copy in ipsec-tools get updated?

You just broke the userland ABI which must not happen.  at all.  That's
why userland having older headers is fine.

> What about applications, ie. normal ones, that want to pass IPSEC
> policies into the kernel via the socket options we have that allows
> per-socket IPSEC rules to be specified?  The copy in ipsec-tools
> doesn't help them at all.

That's why we want the glibc-kernheader package.  Or even better
a package of headers that can be used by the kernel and userland,
but this would require people to properly sort out kernel header
functionality like internal structures and prototypes/inlines from
the actual ABI-relevant contents.  The networking headers currently
are very bad on this.