In one terminal:
$ make
$ sudo insmod mcast-exmpl.ko
$ cd client
$ make
$ ./client
genl ctrl msg
Family ID: 26
Mcast group ID: 4
(IDs may be different)
In another terminal, run a command that will do a TCP connect. mcast-exmpl hooks connects via a jprobe, so doing this will cause it to send a netlink multicast.
$ nc yahoo.com 80
^C
$
In the first terminal, you'll see a netlink multicast was received, even if you did not run client as root.
mcast-exmpl msg
SEND_NUM 55555