Re: per flow stats collection using libnetfilter_conntrack

[Tarun Khanna <tkhanna@akamai.com>]

> Tarun Khanna <tkhanna@akamai.com> wrote:
>> On 02/27/2017 05:12 PM, Florian Westphal wrote:
>>> Tarun Khanna <tkhanna@akamai.com> wrote:
>>>> Is it possible to register for callbacks so that a user application is
>>>> updated on a regular basis when the packet or bytes counts change for flows?
>>> No, update to packet/byte count doesn't trigger an event (it would
>>> trigger too often).
>> I was hoping if there was an option to set a timeout, so that an update
>> would trigger every 5 seconds for flows where the counters have changed.
> No, there is no such feature at the moment.
>
>> I have an application that needs to keep track of per flow stats for all tcp
>> flows destined to port 80. The best way I have found so far is to call
>> nfct_query regularly and to go through each flow returned to retrieve the
>> counters. Would that be the best way to do it?
> Its your only option right now.  If you need a periodic update feature
> we'll need to think about how to best make this.
>
> We now have a periodic gc worker in conntrack so we could probably do
> this without re-adding a per-conntrack timer.

Thank you. The current way of polling works for me. I was thinking about 
it and it doesn't really make a difference if the library sends me 
updates periodically or if I check for them because in both cases I'll 
need to setup some event on epoll (either a timer or the netfilter fd). 
So, functionally both would be the same. Thanks again for your help.