/
net_headers.h
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/
net_headers.h
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/**
* author : 丁雪峰
* time : 2015-07-11 21:19:03
* email : fengidri@yeah.net
* version : 1.0.1
* description :
*/
#ifndef __NET_HEADERS_H__
#define __NET_HEADERS_H__
#include "sys/socket.h"
#include "sys/types.h"
#pragma pack(1)
/* default snap length (maximum bytes per packet to capture) */
#define SNAP_LEN 1518
/* ethernet headers are always exactly 14 bytes [1] */
#define SIZE_ETHERNET 14
/* Ethernet addresses are 6 bytes */
#define ETHER_ADDR_LEN 6
#define NETWORK_TYPE_IP 0x0800
#define TRANSPORT_TYPE_TCP 0x06
/* Ethernet header */
struct header_ethernet {
u_char ether_dhost[ETHER_ADDR_LEN]; /* destination host address */
u_char ether_shost[ETHER_ADDR_LEN]; /* source host address */
u_short ether_type; /* IP? ARP? RARP? etc */
u_char network[];
};
/* IP header */
struct header_ip {
u_char ip_vhl; /* version << 4 | header length >> 2 */
u_char ip_tos; /* type of service */
u_short ip_len; /* total length */
u_short ip_id; /* identification */
u_short ip_off; /* fragment offset field */
#define IP_RF 0x8000 /* reserved fragment flag */
#define IP_DF 0x4000 /* dont fragment flag */
#define IP_MF 0x2000 /* more fragments flag */
#define IP_OFFMASK 0x1fff /* mask for fragmenting bits */
u_char ip_ttl; /* time to live */
u_char ip_p; /* protocol */
u_short ip_sum; /* checksum */
struct in_addr ip_src,ip_dst; /* source and dest address */
};
#define IP_HL(ip) (((ip)->ip_vhl) & 0x0f)
#define IP_V(ip) (((ip)->ip_vhl) >> 4)
/* TCP header */
typedef u_int tcp_seq;
struct header_tcp {
u_short th_sport; /* source port */
u_short th_dport; /* destination port */
tcp_seq th_seq; /* sequence number */
tcp_seq th_ack; /* acknowledgement number */
u_char th_offx2; /* data offset, rsvd */
#define TH_OFF(th) (((th)->th_offx2 & 0xf0) >> 4)
u_char 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
#define TH_ECE 0x40
#define TH_CWR 0x80
#define TH_FLAGS (TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG|TH_ECE|TH_CWR)
u_short th_win; /* window */
u_short th_sum; /* checksum */
u_short th_urp; /* urgent pointer */
};
#pragma pack()
#endif