Date: Sun, 15 Feb 2015 21:39:07 +0100
From: Gert Doering <gert@...1296...>
Message-ID: <20150215203906.GO8134@...1296...>
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Subject: Re: [Openvpn-devel] [PATCH] Print remote IPv4 address on a
	dual-stack v6 socket in IPv4 format
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To: Arne Schwabe <arne@...1227...>
Cc: openvpn-devel@lists.sourceforge.net

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Hi,

On Mon, Feb 09, 2015 at 10:04:03AM +0100, Arne Schwabe wrote:
> > --- a/src/openvpn/mroute.c
> > +++ b/src/openvpn/mroute.c
> > @@ -426,8 +426,16 @@ mroute_addr_print_ex (const struct mroute_addr *ma,
> >  	  break;
> >  	case MR_ADDR_IPV6:
> >  	  {
> > -	    buf_printf (&out, "%s",
> > -		  print_in6_addr( *(struct in6_addr*)&maddr.addr, 0, gc));=20
> > +	    if ( IN6_IS_ADDR_V4MAPPED( (struct in6_addr*)&maddr.addr ) )
> > +	      {
> > +		buf_printf (&out, "%s",
> > +		     print_in_addr_t( *(in_addr_t*)(&maddr.addr[12]), IA_NET_ORDER, =
gc));
> Have you checked that this is endian safe?

Yep, both by running on i386 and on sparc64 - and then by staring at the
code and wondering why it works.

Thing is that print_in_addr_t() takes a flag, IA_NET_ORDER, which tells it
"that 32bit thingie you're printing now is in network byte order", so it
will not call htonl() on it before passing to inet_ntoa(), which wants
network byte order.

(And the IPv6 address is "just an array of 16 octets", no possible confusion
here with 32bit integer representation)
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