How to filter packets marked by 'so_mark' using TC

Question

I use so_mark to mark packets sent from a specific socket.
Now I want to filter these packets from a class in my TC (from HTB mechanism actually).
What is the filter to be used (and syntax example will be helpful as well)

Answer 1

If anyone wondered :

tc filter add dev eth0 parent 1:0 prio 1 u32 match mark 0x123 0xFFF flowid 1:1