peoplo, when i try to compile this code: # cc -c test.c ---- begin code ---- #define __KERNEL__ #define MODULE #include <linux/module.h> #include <linux/kernel.h> #include <linux/netfilter.h> #include <linux/netfilter_ipv4.h> static struct nf_hook_ops nfho; ---- end code ---- it raise this error: storage size of 'nfho' isn't known what is the problem? velkro.