Messages in this thread |  | | Date | Sun, 07 Jan 2001 22:25:41 -0700 | From | Ben Greear <> |
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jamal wrote: > > On Sun, 7 Jan 2001, Ben Greear wrote: > > > Hrm, what if they just made each IP-SEC interface a net_device? If they > > are a routable entity, with it's own IP address, it starts to look a lot > > like an interface/net_device. > > As in my response to Matti, i thing a netdevice is a generalized link > layer structure and should remain that way.
Yes, but VLANs are a link-layer structure too, and things like tunnels are really link-layer too, as far as protocols using them are concerned.
With tunneling and virtual interfaces, you could conceivably do something like:
OC3 - ATM - Ethernet - VLAN - IP - IP-Sec - IP as well as plain old: Ethernet - IP
Which of these are netdevices?
(I argue that at least the Ethernet-over-ATM, VLAN, and IP-Sec entities could profit from being a net_device at it's core.)
You argue that we should split the net_device into physical and virtual portions.
Perhaps you could give an idea of the data members that would belong in the new structures? I argue that you lose the minute you need one in both structures :)
> > This has seeming worked well for VLANs: Maybe net_device is already > > general enough?? > > I think it is not proper to generalize netdevices for IP. I am not > thinking of dead protocols like IPX, more of other newer encapsulations > such as MPLS etc.
MPLS can run over FrameRelay, Ethernet, and ATM, at the moment (right?).
What if you want to run MPLS over an IP-Sec link? If you want it to magically work, IP-Sec could be a net_device with it's own particular member methods and private data that let it do the right thing.
> > So, what would be the down-side of having VLANs and other virtual interfaces > > be net_devices? The only thing I ever thought of was the linear lookups, > > which is why I wrote the hash code. The beauty of working with existing > > user-space tools should not be over-looked! > > > > IP configuration tools you mean. Fine, they should be used to configure > "interfaces" in the way i defined them above.
Think also of creating sockets with SOCK_RAW and other lower-level (but user-space) access to the net_device's methods.
> It makes sense from an abstraction and management perspective to have all > virtual interfaces which run on top of a physical interface to be > managed in conjuction with the device.
What if you had an inverse-MUX type of device that spanned two different physical interfaces. Then, one can go down, but the virtual interface is still up. So, there is not a one-to-one coorespondence. At a higher level, what if your interface is some tunnel running over IP. IP in turn can be routed out any physical interface (and may dynamically change due to routing protocols.)
> Device goes down, you destroy them > or send them to a shutdown state (instead of messaging) etc. > > cheers, > jamal
-- Ben Greear (greearb@candelatech.com) http://www.candelatech.com Author of ScryMUD: scry.wanfear.com 4444 (Released under GPL) http://scry.wanfear.com http://scry.wanfear.com/~greear - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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