From mboxrd@z Thu Jan  1 00:00:00 1970
From: Harvey Harrison <harvey.harrison@gmail.com>
Subject: Re: Is there any function similar to inet_ntoa() in Kernel or
 NetFilter ?
Date: Mon, 24 Nov 2008 22:01:50 -0800
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Cc: Julius Volz <julius.volz@gmail.com>, netdev@vger.kernel.org
To: Chuck Lever <chuck.lever@oracle.com>
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On Mon, 2008-11-24 at 21:03 -0500, Chuck Lever wrote:
> On Nov 21, 2008, at Nov 21, 2008, 6:08 PM, Julius Volz wrote:
> > On Thu, Nov 20, 2008 at 10:34 AM, Roar Bj=C3=B8rgum Rotvik <roarbr@=
tihlde.org=20
> > > wrote:
> >> Kunsheng Chen wrote:
> >>> I am doing a project similar to iptable using netfilter, currentl=
y =20
> >>> I want
> >>> to convert a IP address from 'long int' back to dotted address.
> >>>
> >>> I don't know whether there is some functions inside kernel or =20
> >>> netfilter
> >>> that could make that like using inet_ntoa() in <arpa/inet.h>
> >>
> >> How about NIPQUAD and NIPQUAD_FMT (for IPv4):
> >> http://lxr.linux.no/linux+v2.6.27.6/include/linux/kernel.h#L324
> >> http://lxr.linux.no/linux+v2.6.27.6/include/linux/kernel.h#L319
> >
> > In the latest tree, there are now "%pI4" and "%pI6" format options =
=20
> > for printk.
> >
> > For example:
> >
> > printk(KERN_DEBUG "Address: %pI4\n", &v4_addr);
>=20
> I've been watching this with some interest.  Is this API stable now?
>=20
> Is there a way to pass a pointer to a sockaddr and get printk() to =20
> figure out whether it's is an AF_INET or AF_INET6 address, and displa=
y =20
> it appropriately?

Nope, they're fixed-format currently.  They are pretty simple format
specifiers at this point.  I'm not sure if adding more dynamic behavior
is a good idea.

>=20
> Does it handle IPv6 scope IDs correctly?

Define correctly? ;-)

>=20
> Does it convert IPv6 mapped IPv4 addresses to dotted quad automatical=
ly?
>=20

Nope.

Quick summary:
%pI4 prints 4 decimal separated decimal numbers

%pI6 prints 8 16-bit hex numbers colon-separated=20
%pi6 omits the colons.

Harvey