usr/src/sys/netinet/if_ether.h

/*      if_ether.h      4.4     83/03/15        */

/*
 * Structure of a 10Mb/s Ethernet header.
 */
struct  ether_header {
        u_char  ether_dhost[6];
        u_char  ether_shost[6];
        u_short ether_type;
};

#define ETHERPUP_PUPTYPE        0x0400          /* PUP protocol */
#define ETHERPUP_IPTYPE         0x0800          /* IP protocol */
#define ETHERPUP_ARPTYPE        0x0806          /* Addr. resolution protocol */

/*
 * The ETHERPUP_NTRAILER packet types starting at ETHERPUP_TRAIL have
 * (type-ETHERPUP_TRAIL)*512 bytes of data followed
 * by a PUP type (as given above) and then the (variable-length) header.
 */
#define ETHERPUP_TRAIL          0x1000          /* Trailer PUP */
#define ETHERPUP_NTRAILER       16

#define ETHERMTU        1500
#define ETHERMIN        (60-14)

u_char etherbroadcastaddr[6];                   /* 6 bytes of 0xFF */

/*
 * Ethernet Address Resolution Protocol.
 *
 * See RFC 826 for protocol description.  Structure below is adapted
 * to resolving internet addresses.  Field names used correspond to
 * RFC 826.
 */
struct  ether_arp {
        u_short arp_hrd;        /* format of hardware address */
#define ARPHRD_ETHER    1       /* ethernet hardware address */
        u_short arp_pro;        /* format of proto. address (ETHERPUP_IPTYPE) */
        u_char  arp_hln;        /* length of hardware address (6) */
        u_char  arp_pln;        /* length of protocol address (4) */
        u_short arp_op;
#define ARPOP_REQUEST   1       /* request to resolve address */
#define ARPOP_REPLY     2       /* response to previous request */
        u_char  arp_sha[6];     /* sender hardware address */
        u_char  arp_spa[4];     /* sender protocol address */
        u_char  arp_tha[6];     /* target hardware address */
        u_char  arp_tpa[4];     /* target protocol address */
};

#ifdef  KERNEL
/*
 * Structure shared between the ethernet driver modules and
 * the address resolution code.  For example, each ec_softc or il_softc
 * begins with this structure.
 */
struct  arpcom {
        struct  ifnet ac_if;    /* network-visible interface */
        u_char  ac_enaddr[6];   /* ethernet hardware address */
        struct  arpcom *ac_ac;  /* link to next ether driver */
};

struct  in_addr arpmyaddr();
struct  arptab *arptnew();
#endif