LibIPQ issue

["Sérgio Bernardino" <sergio.bernardino@gmail.com>]

Greetings to all.
I have a small problem in regards to libipq and the effects of
altering packets in userspace. I was wondering if anyone could help me
clear the issue. Here's the situation:
Consider three machines: A, B and C. They are located in a LAN. Now, i
sent a packet from A to B. On the machine B i have the following
iptables rule:

iptables -t mangle -A PREROUTING -p ip -j QUEUE

Inside the program i created to deal with the packets i queue into
userspace i change the destination address on the IP header to point
to the machine C and ACCEPT the packet with all the changes. Now, as
far as i can tell and for what i've gathered from reading this,

http://iptables-tutorial.frozentux.net/chunkyhtml/traversingoftables.html 

I'm changing the packet before the routing decision, hence, it should
continue to traverse the network and reach machine C instead of
"staying" on machine B. The thing is, nothing happens. I'm sure the
packet is valid, and that i recalculate the checksum correctly and
such since i've tested it several times. In fact, in the case where i
have the following iptables rule:

iptables -t filter -A OUTPUT -p ip -j QUEUE

I can alter the destination address of the outgoing packet (for
example, a packet that goes from A to B becomes a packet that goes
from A to A, a localhost packet), and it all works fine.
I seems like i'm doing something wrong but i can't quite figure out
what. Any ideas?
Thank you.
-- 
Sérgio Bernardino

============================================
"The Dragon awakens in the darkness
with a frozen heart he roars.
If you are close, the dragon sleeps
And when the wings appear before him
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