Request: Allocate a Netlink Family Number for MPLS

Request: Allocate a Netlink Family Number for MPLS

[Ramon Casellas]

Jamal/Dave/all,

We're working in porting mpls for linux to 2.6 and one of the planned
features is to move from an IOCTL based approach to a Netlink based one
for updating/querying the MPLS FTN/ILM/Label Mapping/... tables from
userspace. Since netlink families are public, I would
like to know if it is possible to reserve a family for MPLS, even though
the MPLS patch is not part of the official kernel.

Please let me know who I should contact/forward my request (Dave Miller
is listed as the main mantainer of the net core) or if, on the contrary,
there are valid reasons to reject our request.

Thanks in advance,
Ramon


Something like this:

diff -urN linux-2.6.0-test11/include/linux/netlink.h
linux-2.6.0-test11-mpls/include/linux/netlink.h
--- linux-2.6.0-test11/include/linux/netlink.h  2003-11-27
14:24:00.000000000 +0100
+++ linux-2.6.0-test11-mpls/include/linux/netlink.h     2003-11-30
13:47:45.000000000 +0100
@@ -12,6 +12,11 @@
 #define NETLINK_NFLOG          5       /* netfilter/iptables ULOG */
 #define NETLINK_XFRM           6       /* ipsec */
 #define NETLINK_ARPD           8
+
+##if defined(CONFIG_MPLS) || defined(CONFIG_MPLS_MODULE)
+#define NETLINK_MPLS           9
+#endif
+
 #define NETLINK_ROUTE6         11      /* af_inet6 route comm channel */
 #define NETLINK_IP6_FW         13
 #define NETLINK_DNRTMSG                14      /* DECnet routing messages
*/



// -------------------------------------------------------------------
// Ramon Casellas - GET/ENST/INFRES/RHD/A508 - casellas@infres.enst.fr

Re: Request: Allocate a Netlink Family Number for MPLS

[Christoph Hellwig]

On Mon, Dec 01, 2003 at 03:36:26PM +0100, Ramon Casellas wrote:
>  #define NETLINK_ARPD           8
> +
> +##if defined(CONFIG_MPLS) || defined(CONFIG_MPLS_MODULE)
> +#define NETLINK_MPLS           9
> +#endif
> +

This is bogus - either it's reserved or not, so the ifdef doesn't
make sense. 

Also given that Dave & co are working on mpls already I wonder
whether it's a good idea to reserve this, but I'll let him speak
for himself :)

Re: Request: Allocate a Netlink Family Number for MPLS

[Ramon Casellas]

On Mon, 1 Dec 2003, Christoph Hellwig wrote:

> On Mon, Dec 01, 2003 at 03:36:26PM +0100, Ramon Casellas wrote:
> >  #define NETLINK_ARPD           8
> > +
> > +#if defined(CONFIG_MPLS) || defined(CONFIG_MPLS_MODULE)
> > +#define NETLINK_MPLS           9
> > +#endif
> > +
>
> This is bogus - either it's reserved or not, so the ifdef doesn't
> make sense.

Yes of course :) that was just a cut&paste from an interim patch, where we
put ifdefs around everything. If you decide to allocate a family number,
then ifdefs don't make sense (much like in if_ether.h or ppp_defs.h), but
you're right, my mistake, I didn't mean to propose a real patch.


>
> Also given that Dave & co are working on mpls already I wonder
> whether it's a good idea to reserve this, but I'll let him speak
> for himself :)

Well, we are still coordinating efforts, and Jamal has some design docs
around... but regardless of the actual implementation, a mechanism to
communicate with userspace will be needed, and IM(Very, very)HO, netlink
is a good candidate, analog to rtnetlink, but this is open to discussion.

Thanks,
R.

Re: Request: Allocate a Netlink Family Number for MPLS

[jamal]

On Mon, 2003-12-01 at 14:26, Ramon Casellas wrote:

> 
> Well, we are still coordinating efforts, and Jamal has some design docs
> around... but regardless of the actual implementation, a mechanism to
> communicate with userspace will be needed, and IM(Very, very)HO, netlink
> is a good candidate, analog to rtnetlink, but this is open to discussion.
> 

Please leave this alone because the code i have is taking care of this
(i.e it uses netlink). And the grander plan is to use the same code
for bridging and VLANs as well.
I will share the code once James and everybody else reviews things.

cheers,
jamal

Re: Request: Allocate a Netlink Family Number for MPLS

[David S. Miller]

On Mon, 1 Dec 2003 15:36:26 +0100 (MET)
Ramon Casellas <casellas@infres.enst.fr> wrote:

> We're working in porting mpls for linux to 2.6 and one of the planned
> features is to move from an IOCTL based approach to a Netlink based one
> for updating/querying the MPLS FTN/ILM/Label Mapping/... tables from
> userspace. Since netlink families are public, I would
> like to know if it is possible to reserve a family for MPLS, even though
> the MPLS patch is not part of the official kernel.

You don't need a whole new netlink family.  Just create a dummy
address family for MPLS (ie. AF_MPLS) and then just use
NETLINK_ROUTE.

Re: Request: Allocate a Netlink Family Number for MPLS

[James R. Leu]

On Mon, Dec 01, 2003 at 12:45:32PM -0800, David S. Miller wrote:
> On Mon, 1 Dec 2003 15:36:26 +0100 (MET)
> Ramon Casellas <casellas@infres.enst.fr> wrote:
> 
> > We're working in porting mpls for linux to 2.6 and one of the planned
> > features is to move from an IOCTL based approach to a Netlink based one
> > for updating/querying the MPLS FTN/ILM/Label Mapping/... tables from
> > userspace. Since netlink families are public, I would
> > like to know if it is possible to reserve a family for MPLS, even though
> > the MPLS patch is not part of the official kernel.
> 
> You don't need a whole new netlink family.  Just create a dummy
> address family for MPLS (ie. AF_MPLS) and then just use
> NETLINK_ROUTE.

Agreed.  One could also use AF_MPLS for applications to register for
data associated with the router alert label.  I suppose one
could also go completly nuts and allow an application to open stream
connection that talks and listens on a specific label, but I think 
that is a bit overboard.

-- 
James R. Leu
jleu@mindspring.com