Create TCP syn packet with given seq num and few other TCP parameters

Hi All,
Can somebody please tell me how can i create a TCP syn packet with
given seq number and few other para meters set with value provided by
my code ??
This is to be done from my kernel module which inserts its hooks using
Netfilter.
I looked at tcp_output.c and few other files but there doesn't seem to
be a very clean interface
which i can directly use from my module .

Can somebody point me the to way in which this should be done without
much efforts ??
I mean somebody must have done similar kind of thing . Is there
something i can use directly ??

Regards,
Rohit

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