hai, i am a new bie. when i am trying to compile the following program #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; unsigned int hook_func(unsigned int hooknum, struct sk_buff **skb, const struct net_device *in, const struct net_device *out, int (*okfn)(struct sk_buff *)) { return NF_DROP; } int init_module() { nfho.hook=hook_func; nfho.hooknum=NF_IP_PRE_ROUTING; nfho.pf=PF_INET; nfho.priority=NF_IP_PRI_FIRST; nf_register_hook(&nfho); return 0; } void cleanup_module() { nf_unregister_hook(&nfho); } i got the following errors . [root@localhost vamsi]# gcc -c p1.c In file included from p1.c:7: /usr/include/linux/netfilter_ipv4.h:53: `INT_MIN' undeclared here (not in a function) /usr/include/linux/netfilter_ipv4.h:53: enumerator value for `NF_IP_PRI_FIRST' not integer constant /usr/include/linux/netfilter_ipv4.h:59: `INT_MAX' undeclared here (not in a function) /usr/include/linux/netfilter_ipv4.h:59: enumerator value for `NF_IP_PRI_LAST' not integer constant p1.c:15: warning: `struct net_device' declared inside parameter list p1.c:15: warning: its scope is only this definition or declaration, which is probably not what you want p1.c:15: warning: `struct sk_buff' declared inside parameter list p1.c: In function `init_module': p1.c:22: invalid use of undefined type `struct nf_hook_ops' p1.c:23: invalid use of undefined type `struct nf_hook_ops' p1.c:24: invalid use of undefined type `struct nf_hook_ops' p1.c:24: `PF_INET' undeclared (first use in this function) p1.c:24: (Each undeclared identifier is reported only once p1.c:24: for each function it appears in.) p1.c:25: invalid use of undefined type `struct nf_hook_ops' p1.c: At top level: p1.c:9: storage size of `nfho' isn't known please help me, thanks, vamsi ________________________________________________________________________ Yahoo! India Mobile: Download the latest polyphonic ringtones. Go to http://in.mobile.yahoo.com