ULOG buffer flush timeout

ULOG buffer flush timeout

[gofers]

Hi,
I've sent this mail to the netfilter list but nobody responded :(
Could anybody answer my questions, please?

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I'm developing an application which uses the ULOG target as a manner of copying
packets from the FORWARD chain to the userspace. One of the goals of the
application is to store received packets as soon as they arrive from the
network.  Unfortunately I found annoying problem with the timeout of a netlink
queue. I set the ulog-qthreshold parameter of the ULOG target to the lowest
possible value (1). When new packets are not arriving, the last received packet
is not being passed to the userspace but stays in buffer for about 10 seconds.
During this time my application doesn't know anything about it and therefore it
doesn't work correctly. It just waits assuming there are no new packets.

The questions are:
 - is there any patch available which corrects this annoying behavior ?
 - or how can I change the buffer flush timeout without recompiling kernel or iptables ?
 - and what is the lowest possible buffer flush timeout in ULOG module?

I'd like NOT to download and compile any newest kernel source, because I'm
using a POTS modem. I would be grateful if anybody can help me. It's urgent,
because I have to have my app working till Thursday.

I'm using:
 - Linux kernel 2.4.23-bk16
 - iptables 1.2.9
 - libipulog.c 1.11, libipulog.h 1.7
 - glibc 2.2.4
 - gcc 2.95.3 / gcc 3.3.3

best regards
Pawel

Re: ULOG buffer flush timeout

[Pablo Neira]

gofers@poczta.onet.pl wrote:

>I'm developing an application which uses the ULOG target as a manner of copying
>packets from the FORWARD chain to the userspace. One of the goals of the
>application is to store received packets as soon as they arrive from the
>network.  Unfortunately I found annoying problem with the timeout of a netlink
>queue. I set the ulog-qthreshold parameter of the ULOG target to the lowest
>possible value (1). When new packets are not arriving, the last received packet
>is not being passed to the userspace but stays in buffer for about 10 seconds.
>  
>

That was fixed some time ago, please have a look at:

https://lists.netfilter.org/pipermail/netfilter-devel/2004-July/016102.html

--
Pablo