From: "Sachin Shelar" <sachin.s@s7solutions.com>
To: linux-kernel@vger.kernel.org
Subject: kernel module acquiring virtual ip's
Date: Tue, 18 Apr 2006 15:44:58 +0530 [thread overview]
Message-ID: <ops76728o1ibd9oo@sachin> (raw)
Hi,
I have a kernel module which "acquires" virtual ips ( not assigned to
anyone in n/w )
and then respond to any future packets coming to this virtual ip.
I am handling ARP, TCP, UDP protocols in my module.
To get the arp stuff working I handle all the ARP requests for virtual IP
and reply to
them with my local hardware address. I can now receive all the packets
destined to virtual IP.
E.g Local IP is 192.168.1.2
Virtual ip is 192.168.1.244 ( Not existing in network )
I catch every arp request for .244 and reply with my mac. I can now
recive all IP packets ( handled in my netfilter hooks ) destined for .244.
According to the natting rules in my module I nat the packets for .244 and
redirect them to
some listening port on 192.168.1.2
Also I handle all the outgoing packet from 192.168.1.2 and replace the
source to 192.168.1.244
So that the client machine recives reply from virual IP, as expected.
192.168.1.21[32774] -> 192.168.1.244[123]
Nat Destination 192.168.1.21[32774] ->
192.168.1.2[23]
(Reply) 192.168.1.2[23] -> 192.168.1.21[32774]
Nat Source 192.168.1.244[123] ->
192.168.1.21[32774].
Module works perfectly and I can establish any tcp connection ( E.g
telnet ) with a non exitsing
IP ( 192.168.1.244) from any machine in the network.
Problem is :-
I want the same behaviour from the module if I try to connect from the
same machine (local machine )
to the virtual IP.
E.g 192.168.1.2[32772] -> 192.168.1.244[123]
Nat Destination 192.168.1.2[32772] ->
192.168.1.2[23]
***** But somehow this packet after natting is dropped be the kernel and
never reaches 192.168.1.2[23]
Is this because the source and destination ip of this packet is same
?????
Hoping to get good reponse for this loooong mail :)
Thanks,
Sachin
reply other threads:[~2006-04-18 10:11 UTC|newest]
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