Jamal Hadi Salim wrote:
On Tue, 2006-01-08 at 08:08 -0400, John W. Linville wrote:
[..]
There is no doubt that we need to be able to do all three (vlan,
bridge, bond) at once. I'm just not convinced we need to support
stacking them in every conceivable order.
In theory there should be no issues stacking netdevices in any order
you want. In other words the hooks for doing so exist (albeit in some
limited way[1]). Practically, some of the topologies of interconnected
netdevices dont make a lot of sense. The danger is in restricting how
the stacking happens and overlooking some future creative use.
Safer to let the user own the policy and configure any way they want aka
"shoot themselves in the foot".
And, I think that a
reconsideration of all three functions as a group could lead to
better/cleaner functionality with easier support for extension (e.g.
802.1s).
Agreed. I have some very strong opinions on this subject that i could
share with you if you want. For example, IMO, I think it would be a lot
reasonable to assume that a VLAN or VLANS are attributes of a netdevice
(just like IP addresses or MAC addresses are).
As might be expected, I feel that VLANs are much more
useful as full-featured net devices. I do not believe it is worth
decreasing functionality to try to 'clean up' the code. There are people
doing interesting things with the mentioned virtual devices that the original
developers of the individual parts never envisioned, but I see that only
as a resounding success and validation of the architecture.
It is true that there are some interesting issues about where you add
the hooks to slurp up vlan, bridged, bonded and other type of virtual
device packets.
At least for some of my out-of-the-tree virtual lan devices (mac-vlan, in
particular),
I thought it would be useful to allow dynamic registration of the layer-2 hooks
such
as bridging. This way, where there is no logical way to determine which
virtual interface
should get first chance at a packet, the user can provide the ordering by
adjusting
where the hooks sit in the chain.
Last time I mentioned this feature, it was pointed out that the net-filter
hooks provide,
or come close to providing, this ability to stack. If someone wants to work on
virtual device priority, it might be worth investigating this further and
create an
API that makes this usable from kernel and user-space.
Thanks,
Ben
--
Ben Greear <[EMAIL PROTECTED]>
Candela Technologies Inc http://www.candelatech.com
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