Emit Network Interface Events (ENIE).
enie utilises RTNETLINK to subscribe to network interface state-change events from the kernel. Events matching the user-specified interface (for example, wlan0) are printed to stdout, allowing enie to be coupled with other systems.
Compile:
gcc enie.c -o enie
Run:
./enie wlan0
Events are prefixed by an integer denoting event type and followed by the interface name and any other relevant variables (ie. state or IP address).
States:
0 - UP_CONNECTED
1 - UP_DISCONNECTED
2 - DOWN
3 - IP_ASSIGNED
4 - IP_DELETED
Examples:
0_wlan0_UP_CONNECTED
1_wlan0_UP_DISCONNECTED
2_wlan0_DOWN
3_wlan0_IP_ASSIGNED_192.168.1.12
4_wlan0_IP_DELETED
I've been thinking about network interface state and the most efficient way to access and share it. This is my attempt at experimentation with a push-based system, as well as a means of gaining deeper understanding of the Linux kernel and subsystems.