headers.h

局域网内的SNIFFER

#include <stdio.h>  
#include <sys/types.h>  
#include <sys/param.h>  
#include <net/if.h>  
#include <net/if_arp.h> 
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
struct ip {
unsigned int ip_length:4;
unsigned int ip_version:4;
unsigned char ip_tos; 
unsigned short ip_total_length;
unsigned short ip_id;
unsigned short ip_flags;
unsigned char ip_ttl;
unsigned char ip_protocol;
unsigned short ip_cksum;
unsigned int ip_source;
unsigned int ip_dest;
};
struct tcp{ 
unsigned short tcp_source_port;
unsigned short tcp_dest_port;
unsigned int tcp_seqno;
unsigned int tcp_ackno;
unsigned int tcp_resl:4,
             tcp_hlen:4,
             tcp_fin:1,
             tcp_syn:1,
             tcp_rst:1,
             tcp_psh:1,
             tcp_ack:1,
             tcp_urg:1,
             tcp_res2:2;
unsigned short tcp_winsize;
unsigned short tcp_cksum;
unsigned short tcp_urgent;
};