The Tcpdump Group git mirrors - tcpdump/blob - print-arp.c

   1 /*
   2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  */
  21
  22 #ifndef lint
  23 static const char rcsid[] =
  24     "@(#) $Header: /tcpdump/master/tcpdump/print-arp.c,v 1.44 1999-11-21 09:36:48 fenner Exp $ (LBL)";
  25 #endif
  26
  27 #ifdef HAVE_CONFIG_H
  28 #include "config.h"
  29 #endif
  30
  31 #include <sys/param.h>
  32 #include <sys/time.h>
  33 #include <sys/socket.h>
  34
  35 #if __STDC__
  36 struct mbuf;
  37 struct rtentry;
  38 #endif
  39 #include <net/if.h>
  40
  41 #include <netinet/in.h>
  42 #include <netinet/if_ether.h>
  43
  44 #ifdef HAVE_MEMORY_H
  45 #include <memory.h>
  46 #endif
  47 #include <stdio.h>
  48 #include <string.h>
  49
  50 #include "interface.h"
  51 #include "addrtoname.h"
  52 #include "ethertype.h"
  53 #include "extract.h"                    /* must come after interface.h */
  54
  55 /* Compatibility */
  56 #ifndef REVARP_REQUEST
  57 #define REVARP_REQUEST          3
  58 #endif
  59 #ifndef REVARP_REPLY
  60 #define REVARP_REPLY            4
  61 #endif
  62
  63 static u_char ezero[6];
  64
  65 void
  66 arp_print(register const u_char *bp, u_int length, u_int caplen)
  67 {
  68         register const struct ether_arp *ap;
  69         register const struct ether_header *eh;
  70         register u_short pro, hrd, op;
  71
  72         ap = (struct ether_arp *)bp;
  73         if ((u_char *)(ap + 1) > snapend) {
  74                 printf("[|arp]");
  75                 return;
  76         }
  77         if (length < sizeof(struct ether_arp)) {
  78                 (void)printf("truncated-arp");
  79                 default_print((u_char *)ap, length);
  80                 return;
  81         }
  82
  83         pro = EXTRACT_16BITS(&ap->arp_pro);
  84         hrd = EXTRACT_16BITS(&ap->arp_hrd);
  85         op = EXTRACT_16BITS(&ap->arp_op);
  86
  87         if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
  88             || ap->arp_hln != sizeof(SHA(ap))
  89             || ap->arp_pln != sizeof(SPA(ap))) {
  90                 (void)printf("arp-#%d for proto #%d (%d) hardware #%d (%d)",
  91                                 op, pro, ap->arp_pln,
  92                                 hrd, ap->arp_hln);
  93                 return;
  94         }
  95         if (pro == ETHERTYPE_TRAIL)
  96                 (void)printf("trailer-");
  97         eh = (struct ether_header *)packetp;
  98         switch (op) {
  99
 100         case ARPOP_REQUEST:
 101                 (void)printf("arp who-has %s", ipaddr_string(TPA(ap)));
 102                 if (memcmp((char *)ezero, (char *)THA(ap), 6) != 0)
 103                         (void)printf(" (%s)", etheraddr_string(THA(ap)));
 104                 (void)printf(" tell %s", ipaddr_string(SPA(ap)));
 105                 if (memcmp((char *)ESRC(eh), (char *)SHA(ap), 6) != 0)
 106                         (void)printf(" (%s)", etheraddr_string(SHA(ap)));
 107                 break;
 108
 109         case ARPOP_REPLY:
 110                 (void)printf("arp reply %s", ipaddr_string(SPA(ap)));
 111                 if (memcmp((char *)ESRC(eh), (char *)SHA(ap), 6) != 0)
 112                         (void)printf(" (%s)", etheraddr_string(SHA(ap)));
 113                 (void)printf(" is-at %s", etheraddr_string(SHA(ap)));
 114                 if (memcmp((char *)EDST(eh), (char *)THA(ap), 6) != 0)
 115                         (void)printf(" (%s)", etheraddr_string(THA(ap)));
 116                 break;
 117
 118         case REVARP_REQUEST:
 119                 (void)printf("rarp who-is %s tell %s",
 120                         etheraddr_string(THA(ap)),
 121                         etheraddr_string(SHA(ap)));
 122                 break;
 123
 124         case REVARP_REPLY:
 125                 (void)printf("rarp reply %s at %s",
 126                         etheraddr_string(THA(ap)),
 127                         ipaddr_string(TPA(ap)));
 128                 break;
 129
 130         default:
 131                 (void)printf("arp-#%d", op);
 132                 default_print((u_char *)ap, caplen);
 133                 return;
 134         }
 135         if (hrd != ARPHRD_ETHER)
 136                 printf(" hardware #%d", hrd);
 137 }