how to create a TCP packet w/data in interrupt context?

[Tobias DiPasquale <codeslinger@gmail.com>]

Hi all,

I want to be able to create a TCP packet in an iptables rules, similar
to what REJECT --reject-with tcp-reset does, but this packet needs
some data to go in the payload. Is there some iptables rule or kernel
subsystem that already does this that I could look at for reference?
Or, does anyone have an idea of how I would go about doing this? I
already have a n RST that I am creating before this (a la REJECT), so
I figured I would just skb_copy_expand() that packet and add the
payload, but I'm not sure which fields in which structures need to be
updated when I do that.

I looked at pktgen, but that creates UDP packets. I also looked at the
TCP stack, but that copies its data from userland and I wasn't sure if
that series of operations would be the same from an iptables rule in
interrupt context. Anybody have any ideas on how to do this? Thanks.

-- 
[ Tobias DiPasquale ]
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