Message-ID: <427D3E7E.2020405@yahoo.com>
Date: Sat, 07 May 2005 18:17:34 -0400
From: "J. Scott Kasten" <jscottkasten@yahoo.com>
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To: rajat swarup <rajats@gmail.com>
CC: linux-kernel@vger.kernel.org
Subject: Re: sending ICMP messages in kernel module
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rajat swarup wrote:

>Hi,
>I have placed a netfilter hook in which I grab the packets in the
>pre-routing stage.
>I need to send ICMP messages in response to certain messages in this hook.
>I looked at alloc_skb(), skb_reserve() and skb_put() functions but it
>is still not clear to me as to how to construct the packets using
>these methods.
>Since I am getting the packets in the Pre-routing stage should I
>explicitly construct the MAC header, IP header & data & ICMP message?
>Also, I'll need to calculate the checksum to be transmitted in the
>ICMP packet...which method could I use to do that?
>  
>
Hello,

I had a similar problem once.  In the icmp.c file, look at how the ping 
echo reply works.  That is as close to a tutorial as you will find in 
the code.  I think you might find it strait forward from there.

-Scott-

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