1 /* $OpenBSD: print-arp.c,v 1.9 2000/10/03 14:31:56 ho 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 #ifndef lint 25 static const char rcsid[] = 26 "@(#) $Header: /home/cvs/src/usr.sbin/tcpdump/print-arp.c,v 1.9 2000/10/03 14:31:56 ho Exp $ (LBL)"; 27 #endif 28 29 #include <sys/param.h> 30 #include <sys/time.h> 31 #include <sys/socket.h> 32 33 #ifdef __STDC__ 34 struct mbuf; 35 struct rtentry; 36 #endif 37 #include <net/if.h> 38 39 #include <netinet/in.h> 40 #include <netinet/if_ether.h> 41 42 #include <memory.h> 43 #include <stdio.h> 44 #include <string.h> 45 46 #include "interface.h" 47 #include "addrtoname.h" 48 #include "ethertype.h" 49 #include "extract.h" /* must come after interface.h */ 50 51 /* Compatibility */ 52 #ifndef REVARP_REQUEST 53 #define REVARP_REQUEST 3 54 #endif 55 #ifndef REVARP_REPLY 56 #define REVARP_REPLY 4 57 #endif 58 59 static u_char ezero[6]; 60 61 void 62 arp_print(register const u_char *bp, u_int length, u_int caplen) 63 { 64 register const struct ether_arp *ap; 65 register const struct ether_header *eh; 66 register u_short pro, hrd, op; 67 68 ap = (struct ether_arp *)bp; 69 if ((u_char *)(ap + 1) > snapend) { 70 printf("[|arp]"); 71 return; 72 } 73 if (length < sizeof(struct ether_arp)) { 74 (void)printf("truncated-arp"); 75 default_print((u_char *)ap, length); 76 return; 77 } 78 79 pro = EXTRACT_16BITS(&ap->arp_pro); 80 hrd = EXTRACT_16BITS(&ap->arp_hrd); 81 op = EXTRACT_16BITS(&ap->arp_op); 82 83 if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) 84 || ap->arp_hln != sizeof(SHA(ap)) 85 || ap->arp_pln != sizeof(SPA(ap))) { 86 (void)printf("arp-#%d for proto #%d (%d) hardware #%d (%d)", 87 op, pro, ap->arp_pln, 88 hrd, ap->arp_hln); 89 return; 90 } 91 if (pro == ETHERTYPE_TRAIL) 92 (void)printf("trailer-"); 93 eh = (struct ether_header *)packetp; 94 switch (op) { 95 96 case ARPOP_REQUEST: 97 (void)printf("arp who-has %s", ipaddr_string(TPA(ap))); 98 if (memcmp((char *)ezero, (char *)THA(ap), 6) != 0) 99 (void)printf(" (%s)", etheraddr_string(THA(ap))); 100 (void)printf(" tell %s", ipaddr_string(SPA(ap))); 101 if (memcmp((char *)ESRC(eh), (char *)SHA(ap), 6) != 0) 102 (void)printf(" (%s)", etheraddr_string(SHA(ap))); 103 break; 104 105 case ARPOP_REPLY: 106 (void)printf("arp reply %s", ipaddr_string(SPA(ap))); 107 if (memcmp((char *)ESRC(eh), (char *)SHA(ap), 6) != 0) 108 (void)printf(" (%s)", etheraddr_string(SHA(ap))); 109 (void)printf(" is-at %s", etheraddr_string(SHA(ap))); 110 if (memcmp((char *)EDST(eh), (char *)THA(ap), 6) != 0) 111 (void)printf(" (%s)", etheraddr_string(THA(ap))); 112 break; 113 114 case REVARP_REQUEST: 115 (void)printf("rarp who-is %s tell %s", 116 etheraddr_string(THA(ap)), 117 etheraddr_string(SHA(ap))); 118 break; 119 120 case REVARP_REPLY: 121 (void)printf("rarp reply %s at %s", 122 etheraddr_string(THA(ap)), 123 ipaddr_string(TPA(ap))); 124 break; 125 126 default: 127 (void)printf("arp-#%d", op); 128 default_print((u_char *)ap, caplen); 129 return; 130 } 131 if (hrd != ARPHRD_ETHER) 132 printf(" hardware #%d", hrd); 133 } 134