Bind TUN to IPv4 Subnet

[Georg Wicherski <georg-wicherski@pixel-house.net>]

Hey Folks,

I need to bind a TUN device previously created by open("/dev/net/tun",
O_RW) to a subnet, let's say 10.254.0.0/16. The ultimate goal is to have
a tunnel endpoint for a IPv4 tunnel, where I can after writing the
packet which came over the tunnel to the TUN device use an arbitary
userland socket bound to one of the 2^16 IPs or just all of them with
with INADDR_ANY.

What is the (sequence?) of ioctl's to configure the TUN device into
`listening' on a whole subnet? If possible, I want to just specify a
base address and a prefix length.

Digging into the curent 2.6.x kernel sources didn't help me much (yes,
they are badly commented).


Thanks,
Georg Wicherski