1 /* @(#)if_arp.h 1.5 88/08/19 SMI; from UCB 7.1 1/24/86 */ 2 /* 3 * Copyright (c) 1986 Regents of the University of California. 4 * All rights reserved. The Berkeley software License Agreement 5 * specifies the terms and conditions for redistribution. 6 */ 7 8 /* 9 * $Id: $ 10 * $DateTime: $ 11 * $Change: $ 12 */ 13 14 #ifndef _net_if_arp_h 15 #define _net_if_arp_h 16 17 /* 18 * Address Resolution Protocol. 19 * 20 * See RFC 826 for protocol description. ARP packets are variable 21 * in size; the arphdr structure defines the fixed-length portion. 22 * Protocol type values are the same as those for 10 Mb/s Ethernet. 23 * It is followed by the variable-sized fields ar_sha, arp_spa, 24 * arp_tha and arp_tpa in that order, according to the lengths 25 * specified. Field names used correspond to RFC 826. 26 */ 27 struct arphdr { 28 u_short ar_hrd; /* format of hardware address */ 29 #define ARPHRD_ETHER 1 /* ethernet hardware address */ 30 u_short ar_pro; /* format of protocol address */ 31 u_char ar_hln; /* length of hardware address */ 32 u_char ar_pln; /* length of protocol address */ 33 u_short ar_op; /* one of: */ 34 #define ARPOP_REQUEST 1 /* request to resolve address */ 35 #define ARPOP_REPLY 2 /* response to previous request */ 36 #define REVARP_REQUEST 3 /* Reverse ARP request */ 37 #define REVARP_REPLY 4 /* Reverse ARP reply */ 38 /* 39 * The remaining fields are variable in size, 40 * according to the sizes above, and are defined 41 * as appropriate for specific hardware/protocol 42 * combinations. (E.g., see <netinet/if_ether.h>.) 43 */ 44 #ifdef notdef 45 u_char ar_sha[]; /* sender hardware address */ 46 u_char ar_spa[]; /* sender protocol address */ 47 u_char ar_tha[]; /* target hardware address */ 48 u_char ar_tpa[]; /* target protocol address */ 49 #endif notdef 50 }; 51 #endif 52