RAW socket and CONFIG_FILTER

Applications Programming
1

Hi,
Im doin a project on DHCp client-server setup. i have to use RAW sockets in the code for this. The call PF_PACKET, SOCK_RAW as the first two arguments. The code compiles but when i try to start the Dhcp client, I get an error saying "Make sure CONFIG_PACKET and CONFIG_FILTER is enabled". I tried to build the kernel using a source tree. I found CONFIG_PACKET=y but didnt find CONFIG_FILTER. So i added a line CONFIG_FILTER=y. I got the foll error
Heres a full snapshot of the error :
bash-3.1# make
HOSTLD scripts/kconfig/conf
scripts/kconfig/conf -s arch/i386/Kconfig
.config:384:warning: trying to assign nonexistent symbol FILTER
#
# configuration written to .config
#
CHK include/linux/version.h
UPD include/linux/version.h
CHK include/linux/utsrelease.h
UPD include/linux/utsrelease.h
SYMLINK include/asm -> include/asm-i386
ln: creating symbolic link `include/asm' to `asm-i386': Operation not permitted
make: *** [include/asm] Error 1
bash-3.1#
How else can i add it? Is there ne other way out. Im using Fedora 6 with 2.6.20 source tree.

Pls help
Thanks in advance

2

CONFIG_FILTER has been removed in kernel 2.6.x. Your programs will need to be updated to use another mechanism to compile on a 2.6 kernel, or fallback to use kernel 2.4 if you absolutely want it.

The closest substitute:
http://www.netfilter.org/projects/libnetfilter_queue/index.html

3

Hi
Is there ne other way i can use the foll socket call in kernel 2.6.18 without getting the error message saying "make sure CONFIG_PACKET and CONFIG_FILTER is enabled in the kernel" :
sock = socket(PF_PACKET, SOCK_RAW, htons((short)ETH_P_ALL)

Thanks

4

Is this an educational project and you are supposed to be on the receiving end?

5

@porter
A bit of both. Its my project for graduation hence educational, but i have to finish it. so...

I did try the packages from netfilter.org
When i run the DHCP client, i get the foll messages :
May 6 13:33:20 localhost dhclient: socket: Invalid argument - make sure
May 6 13:33:20 localhost dhclient: CONFIG_PACKET (Packet socket) and CONFIG_FILTER
May 6 13:33:20 localhost dhclient: (Socket Filtering) are enabled in your kernel
May 6 13:33:20 localhost dhclient: configuration!
May 6 13:33:20 localhost dhclient:

So does this mean, filtering is enabled and i can run my project?
Thanks