//core_ehp.h
#ifndef __core_ehp_h
#define __core_ehp_h


#define ETH_ADDR_LEN 6

#include <stdio.h>
#include <pcap.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netinet/ip.h>

typedef const struct pcap_pkthdr cp_pkthdr;
typedef const u_char cu_char;
typedef struct pcap_pkthdr p_pkthr;


typedef struct _eth_hdr eth_hdr;
struct _eth_hdr{
  u_char   src[ETH_ADDR_LEN];
  u_char   dst[ETH_ADDR_LEN];
  u_short  type;
};
#define SIZE_ETH (sizeof(eth_hdr))
typedef struct _ip_hdr ip_hdr;
struct _ip_hdr{
  #if __BYTE_ORDER == __LITTLE_ENDIAN
  u_char hd_len:4;
  u_char version:4;
  #elif __BYTE__ORDER == __BIG_ENDIAN
  u_char version:4;
  u_char hd_len:4;
  #endif
  u_char tos;
  u_short tot_len;


  u_short id;
  #if __BYTE_ORDER == __LITTLE_ENDIAN
  u_short offset:13;//per 8byte
  u_short m_flag:1;//more fragment
  u_short d_flag:1;//don't fragment
  u_short r_flag:1;//reserved
  #endif
  #if __BYTE_ORDER == __BIG_ENDIAN
  u_short r_flag:1;//reserved
  u_short d_flag:1;//don't fragment
  u_short m_flag:1;//more fragment
  u_short offset:13;//per 8byte
  #endif  

  u_char ttl;
  u_char type;
  u_short check;
  u_int src_addr;
  u_int dst_addr;
};
#define SIZE_IP (sizeof(ip_hdr))

typedef struct _tcp_hdr tcp_hdr;
struct _tcp_hdr{
  u_short sport;
  u_short dport;
  u_int seq;
  u_int ack;
  #if __BYTE_ORDER == __LITTLE_ENDIAN
  u_short reserved:4;
  u_short doff:4;//data offset per 4byte;
  #endif
  #if __BYTE_ORDER == __BIG_ENDIAN
  u_short doff:4;
  u_short reserved:4;
  #endif
  u_char flags;
  #define TCP_FIN   0x01
  #define TCP_SYN   0x02
  #define TCP_RST   0x04
  #define TCP_PUSH  0x08
  #define TCP_ACK   0x10
  #define TCP_URG   0x20
  u_short window;
  u_short check;
  u_short urgent;
};
//to do - define udp header
//to do - define icmp header
//to do - define ip6 header
//to do - define icmp6 header
//to do - define igmp header

#endif