SOS! Why there are so many redefinitions?

Hi, all,

	I am a tyro to the Linux. Recently a problem hits me. I am writing a simple IDS,
and I am going to use netfilter in my program. Unfortunately, when I add "#include <linux/skbuff.h>" to the head file, I get lots of redefinition errors, like this: "/usr/include/linux/xxxx.h:22: redefinition of `struct xx', /usr/include/bits/xxxx.h:310: previous definition of `struct xx'".

	The following are head files that have been included:
////////////////////////////
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>
#include <netinet/ip_icmp.h>
#include <netinet/if_ether.h>

#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <signal.h>
#include <unistd.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <linux/sockios.h>
#include <linux/if.h>
////////////////////////////

	Would you please give me a hand?
	Thank you very much.

 				
							Yours truely,
　　　　　　　　　　	　　　　Jiangbo
　　　　　　　　　　　　　　[email protected]
　　　　　　　　　　　　　　　　　2002-11-07