Netgraph <-> disk module

[Jeb Campbell]

First let me say that I'm in way over my head on this one (but you have 
to start somewhere I guess).

Anyway, I'm trying to implement ata-over-ethernet (aoe) as a netgraph 
module -- see http://www.coraid.com for specs and freebsd drivers, or 
http://aoetools.sf.net for user space code (linux only).

As my first kernel programming experience I have completed a netgraph 
node that splits incoming packets off based off ethernet type and then 
sorts them based on aoe shelf/slot to the appropriate hook.

Now I need to write a node that performs aoe on a device.  The disk 
access is where I'm stuck.  Archie mentioned in "All About Netgraph" 
that netgraph could be used to talk to disks -- well here is the chance.

Can anyone point me in the right direction for opening and read/writing 
a device (/dev/ad0s1a, /dev/gvinum/disk1, etc) from kernel code?  I 
think Google is going to ban my ip from all the searching ;) .

Many thanks,

Jeb Campbell
jebc at c4solutions.net