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

If your next question is whether or not if its possible to
exploit a old flaw that isnt fixed yet in tcp/ip to send random syn
packets to a dest computer spoofing the src address of the packet with
an individual's ip address that would be connected to that machine
while incrementing the seq number of those packets attempting to hijack
a session or inject a crafted packet in a way where the server would
process that packet thinking it was the src machine and whether or not
ur router doesnt have egress filtering enabled on it to allow u to send
such spoofed packets... then i suggest you get the mother of all socket
books by Richard Stevens called Unix Network Programming.







will_u_tellmemore wrote:
> 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

Not exactly same .. What am trying to do is migrate connected client
connection to new server where i
will be migrating server application. For that i need to reestablish
those connection on migrated server,
which i am planning to do by sending SYN packet which client has sent(i
have logged it for this time)
while establishing connection with original server before
migration.(obviously with some changes).

So my question is still same ..
Regarding the book , i will take a look into it for sure ..

Thanks,
Rohit