Re: libnetfilter_queue: extracting TCP options.

[Yechiel Levi <gmistick@gmail.com>]

Hi,

You should use the nfq_handle_packet method, and in the callback it
activates use a casting of tcp struct on the payload (nfq_get_payload
method)

timestamp can be achieved from netfilter using the :
nfq_get_timestamp (struct nfq_data *nfad, struct timeval *tv)



2010/11/14 Igor 'Lo' (И.L.) <bombsiteunrested@gmail.com>:
> Hi all,
>
> How one can get TCP packet's options (especially timestamp and MD5)
> using only libnetfilter_queue in userspace?
> Having a callback routine(struct nfq_q_handle *qh, struct nfgenmsg
> *nfmsg, struct nfq_data *nfa, void *data) - which structure may
> contain the desired options set?
>
> Most adequate Netfilter-based code to solve this problem was found in
> linux/net/netfilter/nf_conntrack_proto_tcp.c - not a best kind of
> documentation, but provided a nice method of reading a structure. Now
> just need to get a bytes to read.
>
> cheers,
> Igor
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-- 
Kind Regards,
Yechiel Levi
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