Re: [PATCH] inet_ntop() and ipv4 address

[orc <orc@sibserver.ru>]

On Thu, 25 Jul 2013 02:54:33 -0400
Rich Felker <dalias@aerifal.cx> wrote:

> On Thu, Jul 25, 2013 at 02:42:12PM +0800, orc wrote:
> > On Thu, 25 Jul 2013 01:59:13 -0400
> > Rich Felker <dalias@aerifal.cx> wrote:
> > 
> > > On Thu, Jul 25, 2013 at 12:21:27PM +0800, orc wrote:
> > > > inet_ntop() does not embed plain ipv4 address at end (like
> > > > "::ffff:10.0.0.1"). This patch fixes it, but it is a bit ugly.
> > > > Without it is a bit harder to read logs of some daemons that
> > > > support only one address family socket binding and seeing
> > > > output of 'ss -tn'. Adopt if needed.
> > > 
> > > As I understand it, the "IPv4 compatible" addresses (::a.b.c.d)
> > > are deprecated and have never actually been used in deployed
> > > IPv6. Only the v4-mapped form (::ffff:a.b.c.d) is used/usable.
> > > For the most part, supporting the useless form seems harmless,
> > > but there is one harmful case: it looks like your code will
> > > wrongly convert :: to ::0.0.0.0 instead of plain ::. Is it worth
> > > trying to keep the "v4 compatible" form supported and just
> > > special-casing ::, or should we just drop it?
> > 
> > I think it's still worth supporting ::ffff:a.b.c.d form, just quote
> > from my vsftpd logs:
> 
> Oh I agree the ::ffff:a.b.c.d form is worth supporting. I was asking
> if there's any need to also support the ::a.b.c.d form, which would
> require a special workaround for ::.
> 
> Rich

If it needs hacks that don't worth implementing, then no. Can't
remember where I seen ::a.b.c.d last time.