usr/src/sys/vax/if/if_en.h

/*      if_en.h 4.1     81/11/30        */

/*
 * Structure of a Ethernet header.
 */
struct  en_header {
        u_char  en_shost;
        u_char  en_dhost;
        u_short en_type;
};

#define ENPUP_IPTYPE    0x0800          /* IP protocol */
/*
 * The ENPUP_NTRAILER packet types starting at ENPUP_TRAIL have
 * (type-ENPUP_TRAIL)*512 bytes of data followed
 * by a PUP type (as given above).
 */
#define ENPUP_TRAIL     0x1000          /* Trailer PUP */
#define ENPUP_NTRAILER  16