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 1.43 1999-10-07 23:47:11 mcr Exp $ (LBL)";
  25 #endif
  26
  27 #include <sys/param.h>
  28 #include <sys/time.h>
  29 #include <sys/socket.h>
  30
  31 #if __STDC__
  32 struct mbuf;
  33 struct rtentry;
  34 #endif
  35 #include <net/if.h>
  36
  37 #include <netinet/in.h>
  38 #include <netinet/if_ether.h>
  39
  40 #ifdef HAVE_MEMORY_H
  41 #include <memory.h>
  42 #endif
  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 }