1 /* if_en.h 6.2 85/05/01 */ 2 3 /* 4 * Structure of a Ethernet header. 5 */ 6 struct en_header { 7 u_char en_shost; 8 u_char en_dhost; 9 u_short en_type; 10 }; 11 12 #define ENTYPE_PUP 0x0200 /* PUP protocol */ 13 #define ENTYPE_IP 0x0201 /* IP protocol */ 14 15 /* 16 * The ENTYPE_NTRAILER packet types starting at 17 * ENTYPE_TRAIL have (type-ENTYPE_TRAIL)*512 bytes 18 * of data followed by an Ethernet type (as given above) 19 * and then the (variable-length) header. 20 */ 21 #define ENTYPE_TRAIL 0x1000 /* Trailer type */ 22 #define ENTYPE_NTRAILER 16 23 24 #define EN_BROADCAST 0 /* Hardware broadcast address */ 25