Help in extending netfilter


 
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Old 09-13-2005
Help in extending netfilter

Hi everybody,
I have to write a module for matching in netfilter , extending the netfilter but I'm facing some problems can somebody guide me in that. I know that I need to write matching module working in kernel space and a program in userspace. I went through the HOWTO on netfilter-hacking but faced following problems :
1. In kernel module how is match function different from checkentry function (I got this confusion because a 0 return in checkentry and setting hotdrop to 1 seemed to do same thing). Please explain the meaning of each function elaborately.

2. As described in the HOWTO there is a structure in header file iptables.h that I need for program in userspace but I'm not able to locate this headerfile where can I find it.

If possible please send me an example of any module with both the kernel module and program for taking user input in userspace.

Thanks in advance.

Last edited by Trusted Penguin; 09-15-2005 at 11:59 AM..
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ULOGD(8)						      System Manager's Manual							  ULOGD(8)

NAME
ulogd - netfilter/iptables ULOG daemon SYNOPSIS
ulogd [options] DESCRIPTION
ulogd connects to the netlink device of the Linux kernel and reads messages from the netfilter that get queued with the iptables ULOG tar- get. For this to work you have to compile the ULOG target into your kernel or load the respective module. The received messages can be logged into files or into a mySQL or PostgreSQL database. OPTIONS
-d, --daemon fork ulogd into background (start as daemon) -c <filename>, --configfile <filename> use <filename> as configuration file instead of /etc/ulogd.conf -h, --help show usage information -V, --version show version information and copyright FILES
/etc/ulogd.conf /var/log/ulog/ulogd.log SEE ALSO
There is more documentation about the daemon and the database plugins (including examples) in the directories /usr/share/doc/ulogd /usr/share/doc/ulogd-mysql and /usr/share/doc/ulogd-pgsql AUTHOR
This manual page was written by Joerg Wendland <joergland@debian.org>, for the Debian GNU/Linux system (but may be used by others). Linux Netfilter November 05, 2002 ULOGD(8)