Please use the following commands to run the code:
To compile/clean the kernel module
> make
> make clean

To load/unload the kernel modue:
> sudo insmod netlink_Kernel.ko
> sudo rmmod netlink_Kernel
 
To compile and run the user space application:

> gcc netlink_user_module.c -o netlink_user_module
> ./netlink_user_module

(code generates some warnings, but it is not severe and could be ignored for the time being).