ipfilter not working?

[Tomaž Borštnar]

while compiling kernel for ipfilter...

linking kernel
ip_fil.o: In function `iplattach':
ip_fil.o(.text+0xcd): undefined reference to `pfil_head_get'
ip_fil.o(.text+0xd8): undefined reference to `pfil_head_get'
ip_fil.o(.text+0x103): undefined reference to `pfil_add_hook'
ip_fil.o(.text+0x125): undefined reference to `pfil_add_hook'
ip_fil.o(.text+0x141): undefined reference to `pfil_remove_hook'
ip_fil.o: In function `ipldetach':
ip_fil.o(.text+0x20b): undefined reference to `pfil_head_get'
ip_fil.o(.text+0x216): undefined reference to `pfil_head_get'
ip_fil.o(.text+0x29e): undefined reference to `pfil_remove_hook'
ip_fil.o(.text+0x2c1): undefined reference to `pfil_remove_hook'
*** Error code 1
Temporary thing I presume?

Tomaž