Re: [patch 1/1] Add subsystem accessors

[Pablo Neira Ayuso <pablo@netfilter.org>]

Pablo Neira Ayuso wrote:
> Holger Eitzenberger wrote:
>> Pablo Neira Ayuso wrote:
>>
>>>> Need by newer ulogd v2.
>>> Why do you need this? If I apply this, I'll have to provide support for
>>> people mixing calls to libnfnetlink and libnetfilter_conntrack which can
>>> be a problematic. The subsys handles are encapsulated for that reason.
>>>
>>> If you really need them, I suggest you to use libnfnetlink together with
>>> the low level functions libnetfilter_conntrack functions:
>>> nfct_[build|parse]_conntrack and nfct_build_query.
>> Which would nullify the use of libnetfilter-conntrack with ulogd.
> 
> No way. You're abusing the library APIs. The proper way for what you
> want to do is the following:
> 
> 1) open a nfnl handle
> 2) open a nfnl_subsys_handle
> 3) register the callback
> 4) use nfct_parse_conntrack inside the callback to get the conntrack
> object while you can still access netlink details (such as the sequence
> number).
> 5) use nfct_build_query plus nfnl_query if you want to send request to
> ctnetlink.

I have found an example of this for you in old conntrack-tools release
such as 0.9.3. See netlink.c file. I needed something similar at that
time. Recent releases and current SVN only use libnetfilter_conntrack.

-- 
"Los honestos son inadaptados sociales" -- Les Luthiers