Help on firewall hooks

Hello sir,

I wanted to clarify on some concepts in firewall hooks. I found FW_QUEUE 
as a return type in firewall hook functions in some codes which use 
firewall hooks. I wanted to know the significance of FW_QUEUE. When is 
this used as a return type in firewall hook functions ??
In the tcp/ip code for kernel 2.2.20, in ip_output.c; one of the 
comments says that when call_out_firewall returns FW_QUEUE silently drop 
the skb.
Can you please elaborate on this.


Thanks in advance
Regards
Puja Puri