FreeBSD change for openssh

[Mike Karels]

I submitted this proposed change for openssh a while back, designed to
reduce embedded knowledge of old Class A/B/C networks and use the system's
IN_LOOPBACK macro where it exists.  I received just one comment:

Ed Maste <emaste at freebsd.org> wrote:
> On Mon, 15 Nov 2021 at 11:51, Mike Karels <karels at freebsd.org> wrote:
> >
> > +#ifndef IN_LOOPBACK
> > +#define IN_LOOPBACK(i)         (((i) & 0xff000000) == 0x7f000000)
> > +#endif
> ...
> >  static int
> >  sockaddr_is_local(struct sockaddr *hostaddr)
> >  {
> >         switch (hostaddr->sa_family) {
> >         case AF_INET:
> > -               return (ntohl(((struct sockaddr_in *)hostaddr)->
> > -                   sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
> > +               return (IN_LOOPBACK(ntohl(((struct sockaddr_in *)hostaddr)->
> > +                   sin_addr.s_addr)));

> Looks fine to me.

> IMO #ifndef is reasonable as it's unlikely that IN_LOOPBACK() would be
> implemented as other than a macro anywhere, but could be a full
> autoconf check if that's what OpenSSH folks want.

Any other comments or suggestions?  Any general thoughts on doing this?
I'd like to get it committed if possible.

Thanks,
		Mike