#define  MAXBUF  1024*4
#define  PCAP_TOUT 5
#define  PROMISC 0
#define  TRUE  1
#define  FALSE  0

/* Ethernet protocol ID's */    
#define ETHERTYPE_IP            0x0800          /* IP */


struct ether_header
{
	u_int8_t  ether_dhost[6];      /* destination eth addr */
	u_int8_t  ether_shost[6];      /* source ether addr    */
	u_int16_t ether_type;          /* packet type ID field */
};


struct iphead
{
	u_int8_t ip_header_length;
	u_int8_t ip_tos;
	u_int16_t ip_length;
	u_int16_t ip_id;
	u_int16_t ip_off;
	u_int8_t ip_ttl;
	u_int8_t ip_protocol;
	u_int16_t ip_checksum;
	struct in_addr ip_souce_address;
	struct in_addr ip_destination_address;
};


struct tcphead
  {
    u_int16_t th_sport;         /* source port */
    u_int16_t th_dport;         /* destination port */
    u_int32_t th_seq;             /* sequence number */
    u_int32_t th_ack;             /* acknowledgement number */
    u_int8_t th_off;          /* data offset */
    u_int8_t th_flags;
#define TH_FIN        0x01
#define TH_SYN        0x02
#define TH_RST        0x04
#define TH_PUSH       0x08
#define TH_ACK        0x10
#define TH_URG        0x20
    u_int16_t th_win;           /* window */
    u_int16_t th_sum;           /* checksum */
    u_int16_t th_urp;           /* urgent pointer */
};