1 /* $OpenBSD: print-arp.c,v 1.17 2021/12/01 18:28:45 deraadt Exp $ */ 2 3 /* 4 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that: (1) source code distributions 9 * retain the above copyright notice and this paragraph in its entirety, (2) 10 * distributions including binary code include the above copyright notice and 11 * this paragraph in its entirety in the documentation or other materials 12 * provided with the distribution, and (3) all advertising materials mentioning 13 * features or use of this software display the following acknowledgement: 14 * ``This product includes software developed by the University of California, 15 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 16 * the University nor the names of its contributors may be used to endorse 17 * or promote products derived from this software without specific prior 18 * written permission. 19 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 20 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 21 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 22 */ 23 24 #include <sys/time.h> 25 #include <sys/socket.h> 26 27 #include <net/if.h> 28 29 #include <netinet/in.h> 30 #include <netinet/if_ether.h> 31 32 #include <stdio.h> 33 #include <string.h> 34 35 #include "interface.h" 36 #include "addrtoname.h" 37 #include "ethertype.h" 38 #include "extract.h" /* must come after interface.h */ 39 40 /* Compatibility */ 41 #ifndef REVARP_REQUEST 42 #define REVARP_REQUEST 3 43 #endif 44 #ifndef REVARP_REPLY 45 #define REVARP_REPLY 4 46 #endif 47 48 static u_char ezero[6]; 49 50 void 51 arp_print(const u_char *bp, u_int length, u_int caplen) 52 { 53 const struct ether_arp *ap; 54 const struct ether_header *eh; 55 u_short pro, hrd, op; 56 57 ap = (struct ether_arp *)bp; 58 if ((u_char *)(ap + 1) > snapend) { 59 printf("[|arp]"); 60 return; 61 } 62 if (length < sizeof(struct ether_arp)) { 63 printf("truncated-arp"); 64 default_print((u_char *)ap, length); 65 return; 66 } 67 68 pro = EXTRACT_16BITS(&ap->arp_pro); 69 hrd = EXTRACT_16BITS(&ap->arp_hrd); 70 op = EXTRACT_16BITS(&ap->arp_op); 71 72 if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) 73 || ap->arp_hln != sizeof(SHA(ap)) 74 || ap->arp_pln != sizeof(SPA(ap))) { 75 printf("arp-#%d for proto #%d (%d) hardware #%d (%d)", 76 op, pro, ap->arp_pln, hrd, ap->arp_hln); 77 return; 78 } 79 if (pro == ETHERTYPE_TRAIL) 80 printf("trailer-"); 81 eh = (struct ether_header *)packetp; 82 switch (op) { 83 84 case ARPOP_REQUEST: 85 printf("arp who-has %s", ipaddr_string(TPA(ap))); 86 if (memcmp((char *)ezero, (char *)THA(ap), 6) != 0) 87 printf(" (%s)", etheraddr_string(THA(ap))); 88 printf(" tell %s", ipaddr_string(SPA(ap))); 89 if (memcmp((char *)ESRC(eh), (char *)SHA(ap), 6) != 0) 90 printf(" (%s)", etheraddr_string(SHA(ap))); 91 break; 92 93 case ARPOP_REPLY: 94 printf("arp reply %s", ipaddr_string(SPA(ap))); 95 if (memcmp((char *)ESRC(eh), (char *)SHA(ap), 6) != 0) 96 printf(" (%s)", etheraddr_string(SHA(ap))); 97 printf(" is-at %s", etheraddr_string(SHA(ap))); 98 if (memcmp((char *)EDST(eh), (char *)THA(ap), 6) != 0) 99 printf(" (%s)", etheraddr_string(THA(ap))); 100 break; 101 102 case REVARP_REQUEST: 103 printf("rarp who-is %s tell %s", 104 etheraddr_string(THA(ap)), 105 etheraddr_string(SHA(ap))); 106 break; 107 108 case REVARP_REPLY: 109 printf("rarp reply %s at %s", 110 etheraddr_string(THA(ap)), 111 ipaddr_string(TPA(ap))); 112 break; 113 114 default: 115 printf("arp-#%d", op); 116 default_print((u_char *)ap, caplen); 117 return; 118 } 119 if (hrd != ARPHRD_ETHER) 120 printf(" hardware #%d", hrd); 121 } 122