cvs commit: src/sys/netgraph ng_vlan.c ng_vlan.h src/sys/modules/netgraph Makefile src/sys/modules/netgraph/vlan Makefile src/share/man/man4 Makefile ng_vlan.4

[Ruslan Ermilov]

Hey Yar,

I'm sending my reply to a public mailing list mainly to archive it,
but also in a hope to attract some interested developer's attention.

On Wed, Mar 03, 2004 at 06:45:55PM +0300, Yar Tikhiy wrote:
> Greetings Ruslan,
> 
> On Mon, Mar 01, 2004 at 09:22:16AM -0800, Ruslan Ermilov wrote:
> > ru          2004/03/01 09:22:16 PST
> > 
> >   FreeBSD src repository
> > 
> >   Modified files:
> >     sys/modules/netgraph Makefile 
> >     share/man/man4       Makefile 
> >   Added files:
> >     sys/netgraph         ng_vlan.c ng_vlan.h 
> >     sys/modules/netgraph/vlan Makefile 
> >     share/man/man4       ng_vlan.4 
> >   Log:
> >   Netgraph node type for IEEE 802.1Q VLAN tagging.
> 
> Do I understand right that such issues as VLAN-level multicast
> filtering and hardware tagging, which are handled by if_vlan, can't
> be addressed by ng_vlan due to the nature of Netgraph?
> 
One needs real Ethernet hardware to program its multicast filter.
In case of vlan(4) this is the parent interface.  In the Netgraph
case, the node connected to the "lower" hook is not necessarily
ng_ether(4), yet ng_ether(4) doesn't support programming its
multicast filter through Netgraph control messages.

Similarly with h/w tagging: while ng_vlan(4) supports de-tagging
of hardware supplied tags, it doesn't add tags suitable for h/w
that support h/w VLAN tagging because it does not know what
hardware it's connected to (it may be connected indirectly, or
may be not connected to any real hardware at all, after all).
It should be pretty easy though to add a new control message to
program ng_vlan(4) to supply VLAN tags in the form suitable for
hardware that supports it, rather than encapsulating header into
ETHERTYPE_VLAN.  It's just that I didn't need this functionality.
If somebody needs it, it should be pretty trivial to implement,
and I would be happy to review, test, and commit such a patch.


Cheers,
-- 
Ruslan Ermilov
FreeBSD committer
ru at FreeBSD.org
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