Bazsi's Home Automation blog

After some time I needed to do some kernel coding again. To seamlessly support dynamically created interfaces in Zorp, we need something I called "interface groups". Each interface might belong to a single group that basically describes how the interface was created. For instance there's an interface group for each PPP profile, but an interface group can encapsulate interfaces created by PPTPD. It is quite difficult to match dynamic interfaces by their nature: iptables sports wildcard interface name matching with the '+' character but it only works if interface names have some kind of prefix _AND_ if you don't want to differentiate between two groups. If you have two sets of PPP devices (like in the example I described above), then you have no way to create a separate ruleset, unless you reload iptables everytime a new interface is added to the system. Adding to the burden, in Zorp we want to be able to bind a service to these dynamically created interfaces, o