structs.h

/*
	Copyright 2008 Utah State University    

	This file is part of OIP.

    OIP is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    OIP is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with OIP.  If not, see <http://www.gnu.org/licenses/>.
*/
/* Ethernet addresses are 6 bytes */
#define ETHER_ADDR_LEN	6

/* Ethernet header */
struct sniff_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 */
};
struct sniff_ethernet_8021q {
    u_char ether_dhost[ETHER_ADDR_LEN]; /* Destination host address */
    u_char ether_shost[ETHER_ADDR_LEN]; /* Source host address */
    u_short vlan_tag; /* 0x8100 */
    u_short vlan_id; /* needs masked to get last 12 bits */
    u_short ether_type; /* IP? ARP? RARP? etc */
};
#define VLANID(i) ((i)&0x0fff)

#define SIZE_ETHERNET 14
#define SIZE_8021Q 18

/* IP header */
struct sniff_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 */
    unsigned int  ip_src,ip_dst; /* source and dest address */
};
#define IP_HL(ip)		(((ip)->ip_vhl) & 0x0f)
#define IP_V(ip)		(((ip)->ip_vhl) >> 4)

#define T_IP 0x0800
#define T_VLAN 0x8100
#define T_UDP 17
#define T_TCP 6