Hi,
I am writing a program on Linux ( kernel 2.4.19). This is a routing protocol written in C. This program needs to know the following things:
1. at program startup it should be able to find out all the up network interfaces, including loopbacks.
2. If a new interface comes up at runtime, somehow this program need to get a notification.
3. If a network intercae goes down, again this program need to get a notification.

I need your help here. Any suggestion how can I go about getting these information. Is there some library or some other entry points to the kernel from where this program can get the information.

I am working alone in the project and plan to release it as OSS. Any help will be greatly appreciated.

Thanks,
Manas

The active interfaces can be found by parsing /proc/net/dev. You can look at the source code for ifconfig to see how it does it. As for getting a notification if an iterface comes up or down while you program is running, you would have to modify the kernel. I'd suggest just polling every few seconds.

You can find ifconfig source here:
http://www.tazenda.demon.co.uk/phil/...s-1.60.tar.bz2