Re: [PATCH] inet_ntop() and ipv4 address

[Rich Felker <dalias@aerifal.cx>]

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