Change Packet Payload

Pablo Neira Ayuso pablo at netfilter.org
Tue Feb 13 23:10:16 CET 2007


Hi Eric,

Eric Leblond wrote:
> Le vendredi 09 février 2007 à 10:10 +0100, Luis Campo Giralte a écrit :
>> Hi every one!
>> im using libnetfilter_queue lib, its posible to change any value of the
>> packet, source address, icmp types, payload chars, or any data of the
>> packet received on the Handler (nfq_create_queue(h,0,&MyHandler,NULL))
>> and send it again with the correct checksum?
> 
> Yes, but you have to compute the checksum yourself.

I would accept a patch to introduce a function that computes the
checksum. I think that the library should provide as much helper
functions as possible. We can group such helper functions by protocols
in different files inside the libnetfilter_queue tree. I have already
seen several post in the mailing list on how to retrieve data from the
header and such.

-- 
The dawn of the fourth age of Linux firewalling is coming; a time of
great struggle and heroic deeds -- J.Kadlecsik got inspired by J.Morris



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