[isf-wifidog] Support multiple gateway interfaces

[Wichert Akkerman]

For a project I am working on I need to run a hotspot on multiple subnets 
from a single gateway. Looking around in the widfidog gateway source this 
should not be hard to do: a few changes to make config->gw_interface a list
instead of a single-valued items and change iptables_fw_init to setup the 
rules for all interfaces.

I am wondering what the best way to implement the configuration file logic 
is: it will need a few changes to accomdate GatewayAddress when multiple 
interfaces are present. I would like to propose a simple change:

- modify the GatewayInterface statement to take an optional ip address
   as second parameter
- only accept GatewayAddress if a single GatewayInterface is defined

that way existing configurations continue to work while providing a path for 
multiple gateway interface support.

Wichert.

-- 
Wichert Akkerman <wichert at wiggy.net>    It is simple to make things.
http://www.wiggy.net/                   It is hard to make things simple.