1 /* 2 * Fundamental constants relating to ethernet. 3 * 4 * $Id: ethernet.h,v 1.8 1997/02/22 09:40:58 peter Exp $ 5 * 6 */ 7 8 #ifndef _NET_ETHERNET_H_ 9 #define _NET_ETHERNET_H_ 10 11 /* 12 * The number of bytes in an ethernet (MAC) address. 13 */ 14 #define ETHER_ADDR_LEN 6 15 16 /* 17 * The number of bytes in the type field. 18 */ 19 #define ETHER_TYPE_LEN 2 20 21 /* 22 * The number of bytes in the trailing CRC field. 23 */ 24 #define ETHER_CRC_LEN 4 25 26 /* 27 * The length of the combined header. 28 */ 29 #define ETHER_HDR_LEN (ETHER_ADDR_LEN*2+ETHER_TYPE_LEN) 30 31 /* 32 * The minimum packet length. 33 */ 34 #define ETHER_MIN_LEN 64 35 36 /* 37 * The maximum packet length. 38 */ 39 #define ETHER_MAX_LEN 1518 40 41 /* 42 * A macro to validate a length with 43 */ 44 #define ETHER_IS_VALID_LEN(foo) \ 45 ((foo) >= ETHER_MIN_LEN && (foo) <= ETHER_MAX_LEN) 46 47 /* 48 * Structure of a 10Mb/s Ethernet header. 49 */ 50 struct ether_header { 51 u_char ether_dhost[ETHER_ADDR_LEN]; 52 u_char ether_shost[ETHER_ADDR_LEN]; 53 u_short ether_type; 54 }; 55 56 /* 57 * Structure of a 48-bit Ethernet address. 58 */ 59 struct ether_addr { 60 u_char octet[ETHER_ADDR_LEN]; 61 }; 62 63 #define ETHERTYPE_PUP 0x0200 /* PUP protocol */ 64 #define ETHERTYPE_IP 0x0800 /* IP protocol */ 65 #define ETHERTYPE_ARP 0x0806 /* Addr. resolution protocol */ 66 #define ETHERTYPE_REVARP 0x8035 /* reverse Addr. resolution protocol */ 67 #define ETHERTYPE_VLAN 0x8100 /* IEEE 802.1Q VLAN tagging */ 68 #define ETHERTYPE_LOOPBACK 0x9000 /* used to test interfaces */ 69 /* XXX - add more useful types here */ 70 71 /* 72 * The ETHERTYPE_NTRAILER packet types starting at ETHERTYPE_TRAIL have 73 * (type-ETHERTYPE_TRAIL)*512 bytes of data followed 74 * by an ETHER type (as given above) and then the (variable-length) header. 75 */ 76 #define ETHERTYPE_TRAIL 0x1000 /* Trailer packet */ 77 #define ETHERTYPE_NTRAILER 16 78 79 #define ETHERMTU (ETHER_MAX_LEN-ETHER_HDR_LEN-ETHER_CRC_LEN) 80 #define ETHERMIN (ETHER_MIN_LEN-ETHER_HDR_LEN-ETHER_CRC_LEN) 81 82 #ifndef KERNEL 83 #include <sys/cdefs.h> 84 85 /* 86 * Ethernet address conversion/parsing routines. 87 */ 88 __BEGIN_DECLS 89 struct ether_addr *ether_aton __P((char *)); 90 int ether_hostton __P((char *, struct ether_addr *)); 91 int ether_line __P((char *, struct ether_addr *, char *)); 92 char *ether_ntoa __P((struct ether_addr *)); 93 int ether_ntohost __P((char *, struct ether_addr *)); 94 __END_DECLS 95 #endif /* !KERNEL */ 96 97 #endif /* !_NET_ETHERNET_H_ */ 98