[Bridge] Help needed about IP class finding in a bridge netfilter module

[Louis Croisez]

Hi,
i am currently trying to code a little netfilter plugin, to be placed
into the bridge forwarding path.
In such plugin, i would like to test if a packet is:
- unicast
- multicast
- broadcast

The starting condition is that the bridge has no knowledge of the IP
configuration of the sending and receiving stations. It does not know
about their netmask e.g.

I have tried the following function (from 2.6 kernel):
inet_addr_type(u32 addr), but it always return RTN_UNICAST, and never
RTN_MULTICAST, RTN_BROADCAST.
 For example, for this address: 10.255.255.255 it returns RTN_UNICAST.

How could the bridge decide in which class is the destination IP of a
skb, and what is my error?

Thx in advance.
LOUIS