// TCP IP header
// Chaitanya Belwal

struct IP_HEADER
{
	u_char ip_hl;			// Header Length         -> Bytes = 1
	u_char ip_v;			// Version               -> Bytes = 1
	u_char ip_tos;			// Type of service       -> Bytes = 1
	short ip_len;			// Total length			 -> Bytes = 2
	u_short ip_id;			// Identification		 -> Bytes = 1
	short ip_off;			// Fragment Offset       -> Bytes = 2

	u_char ip_ttl;			// Time to live          -> Bytes = 1
	u_char ip_p;			// Protocol				 -> Bytes = 1

	u_short ip_cksum;		// Checksum				 -> Bytes = 2

	struct in_addr ip_src;  // Source Address		 -> Bytes = 4
	struct in_addr ip_dst;  // Destination Address   -> Bytes = 4
};


struct TCP_HEADER 
{
	u_char  tcp_sp;			// SOURCE PORT				-> Bytes = 2
	u_char  tcp_dp;			// DESTINATION PORT         -> Bytes = 2
	u_char  tcp_sn;			// SEQUENCE NUMBER			-> Bytes = 4
	short   tcp_an;			// ACKNOWLEDGEMENT NUMBER	-> Bytes = 4
	u_short tcp_hl;			// HEADER LENGTH			-> Bytes = 1
	short   tcp_off;		// FLAGS					-> Bytes = 1

	u_char  tcp_win;		// WINDOW					-> Bytes = 2
	u_char  tcp_cksum;		// CHECKSUM					-> Bytes = 2

	u_short tcp_up;		    // URGENT POINTER			-> Bytes = 2

};