TC hashing tables using problem

Hi.

I've tried to configure /29 class as a index to a tc hashing table.
For example I wanted to get an index from IP 192.168.168.52/29,
so for the last octet it is 48 (0x30). I tried to configure traffic:

1 tc filter add dev imq0 protocol ip prio 1 parent 1: handle 3: u32 divisor 32

2 tc filter add dev imq0 protocol ip prio 1 parent 1: \
u32 ht 800: match ip dst 192.168.168.0/16 hashkey mask 0x000000f8 at 16 link 3:

3 tc filter add dev imq0 protocol ip prio 1 parent 1: u32 ht 3:30 \
match ip dst 192.168.168.48/29 flowid 1:2

As you can see in line 2 hashkey mask 0x000000f8 should get me last octet value:
52 & 0xf8 = 48 (0x30). But that filter failed I don't know the reason why.
Could someone suggest me what is wrong in the example above?

Is that possible to use 16-bits as a hashkey mask? How is hash table index looks like?

Stronly confused Zbigniew
--
=============================
Zbigniew Kempczyñski
http://it.marton.pl/wegorz/
=============================