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   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 1.61 2003-01-25 23:27:09 guy Exp $ (LBL)";
  25 #endif
  26
  27 #ifdef HAVE_CONFIG_H
  28 #include "config.h"
  29 #endif
  30
  31 #include <tcpdump-stdinc.h>
  32
  33 #include <stdio.h>
  34 #include <string.h>
  35
  36 #include "interface.h"
  37 #include "addrtoname.h"
  38 #include "ether.h"
  39 #include "ethertype.h"
  40 #include "extract.h"                    /* must come after interface.h */
  41
  42 /*
  43  * Address Resolution Protocol.
  44  *
  45  * See RFC 826 for protocol description.  ARP packets are variable
  46  * in size; the arphdr structure defines the fixed-length portion.
  47  * Protocol type values are the same as those for 10 Mb/s Ethernet.
  48  * It is followed by the variable-sized fields ar_sha, arp_spa,
  49  * arp_tha and arp_tpa in that order, according to the lengths
  50  * specified.  Field names used correspond to RFC 826.
  51  */
  52 struct  arp_pkthdr {
  53         u_short ar_hrd;         /* format of hardware address */
  54 #define ARPHRD_ETHER    1       /* ethernet hardware format */
  55 #define ARPHRD_IEEE802  6       /* token-ring hardware format */
  56 #define ARPHRD_ARCNET   7       /* arcnet hardware format */
  57 #define ARPHRD_FRELAY   15      /* frame relay hardware format */
  58 #define ARPHRD_STRIP    23      /* Ricochet Starmode Radio hardware format */
  59 #define ARPHRD_IEEE1394 24      /* IEEE 1394 (FireWire) hardware format */
  60         u_short ar_pro;         /* format of protocol address */
  61         u_char  ar_hln;         /* length of hardware address */
  62         u_char  ar_pln;         /* length of protocol address */
  63         u_short ar_op;          /* one of: */
  64 #define ARPOP_REQUEST   1       /* request to resolve address */
  65 #define ARPOP_REPLY     2       /* response to previous request */
  66 #define ARPOP_REVREQUEST 3      /* request protocol address given hardware */
  67 #define ARPOP_REVREPLY  4       /* response giving protocol address */
  68 #define ARPOP_INVREQUEST 8      /* request to identify peer */
  69 #define ARPOP_INVREPLY  9       /* response identifying peer */
  70 /*
  71  * The remaining fields are variable in size,
  72  * according to the sizes above.
  73  */
  74 #ifdef COMMENT_ONLY
  75         u_char  ar_sha[];       /* sender hardware address */
  76         u_char  ar_spa[];       /* sender protocol address */
  77         u_char  ar_tha[];       /* target hardware address */
  78         u_char  ar_tpa[];       /* target protocol address */
  79 #endif
  80 #define ar_sha(ap)      (((const u_char *)((ap)+1))+0)
  81 #define ar_spa(ap)      (((const u_char *)((ap)+1))+  (ap)->ar_hln)
  82 #define ar_tha(ap)      (((const u_char *)((ap)+1))+  (ap)->ar_hln+(ap)->ar_pln)
  83 #define ar_tpa(ap)      (((const u_char *)((ap)+1))+2*(ap)->ar_hln+(ap)->ar_pln)
  84 };
  85
  86 #define ARP_HDRLEN      8
  87
  88 #define HRD(ap) EXTRACT_16BITS(&(ap)->ar_hrd)
  89 #define HLN(ap) ((ap)->ar_hln)
  90 #define PLN(ap) ((ap)->ar_pln)
  91 #define OP(ap)  EXTRACT_16BITS(&(ap)->ar_op)
  92 #define PRO(ap) EXTRACT_16BITS(&(ap)->ar_pro)
  93 #define SHA(ap) (ar_sha(ap))
  94 #define SPA(ap) (ar_spa(ap))
  95 #define THA(ap) (ar_tha(ap))
  96 #define TPA(ap) (ar_tpa(ap))
  97
  98 /*
  99  * ATM Address Resolution Protocol.
 100  *
 101  * See RFC 2225 for protocol description.  ATMARP packets are similar
 102  * to ARP packets, except that there are no length fields for the
 103  * protocol address - instead, there are type/length fields for
 104  * the ATM number and subaddress - and the hardware addresses consist
 105  * of an ATM number and an ATM subaddress.
 106  */
 107 struct  atmarp_pkthdr {
 108         u_short aar_hrd;        /* format of hardware address */
 109 #define ARPHRD_ATM2225  19      /* ATM (RFC 2225) */
 110         u_short aar_pro;        /* format of protocol address */
 111         u_char  aar_shtl;       /* length of source ATM number */
 112         u_char  aar_sstl;       /* length of source ATM subaddress */
 113 #define ATMARP_IS_E164  0x40    /* bit in type/length for E.164 format */
 114 #define ATMARP_LEN_MASK 0x3F    /* length of {sub}address in type/length */
 115         u_short aar_op;         /* same as regular ARP */
 116 #define ATMARPOP_NAK    10      /* NAK */
 117         u_char  aar_spln;       /* length of source protocol address */
 118         u_char  aar_thtl;       /* length of target ATM number */
 119         u_char  aar_tstl;       /* length of target ATM subaddress */
 120         u_char  aar_tpln;       /* length of target protocol address */
 121 /*
 122  * The remaining fields are variable in size,
 123  * according to the sizes above.
 124  */
 125 #ifdef COMMENT_ONLY
 126         u_char  aar_sha[];      /* source ATM number */
 127         u_char  aar_ssa[];      /* source ATM subaddress */
 128         u_char  aar_spa[];      /* sender protocol address */
 129         u_char  aar_tha[];      /* target ATM number */
 130         u_char  aar_tsa[];      /* target ATM subaddress */
 131         u_char  aar_tpa[];      /* target protocol address */
 132 #endif
 133
 134 #define ATMHRD(ap)  EXTRACT_16BITS(&(ap)->aar_hrd)
 135 #define ATMSHLN(ap) ((ap)->aar_shtl & ATMARP_LEN_MASK)
 136 #define ATMSSLN(ap) ((ap)->aar_sstl & ATMARP_LEN_MASK)
 137 #define ATMSPLN(ap) ((ap)->aar_spln)
 138 #define ATMOP(ap)   EXTRACT_16BITS(&(ap)->aar_op)
 139 #define ATMPRO(ap)  EXTRACT_16BITS(&(ap)->aar_pro)
 140 #define ATMTHLN(ap) ((ap)->aar_thtl & ATMARP_LEN_MASK)
 141 #define ATMTSLN(ap) ((ap)->aar_tstl & ATMARP_LEN_MASK)
 142 #define ATMTPLN(ap) ((ap)->aar_tpln)
 143 #define aar_sha(ap)     ((const u_char *)((ap)+1))
 144 #define aar_ssa(ap)     (aar_sha(ap) + ATMSHLN(ap))
 145 #define aar_spa(ap)     (aar_ssa(ap) + ATMSSLN(ap))
 146 #define aar_tha(ap)     (aar_spa(ap) + ATMSPLN(ap))
 147 #define aar_tsa(ap)     (aar_tha(ap) + ATMTHLN(ap))
 148 #define aar_tpa(ap)     (aar_tsa(ap) + ATMTSLN(ap))
 149 };
 150
 151 #define ATMSHA(ap) (aar_sha(ap))
 152 #define ATMSSA(ap) (aar_ssa(ap))
 153 #define ATMSPA(ap) (aar_spa(ap))
 154 #define ATMTHA(ap) (aar_tha(ap))
 155 #define ATMTSA(ap) (aar_tsa(ap))
 156 #define ATMTPA(ap) (aar_tpa(ap))
 157
 158 static u_char ezero[6];
 159
 160 static void
 161 atmarp_addr_print(const u_char *ha, u_int ha_len, const u_char *srca,
 162     u_int srca_len)
 163 {
 164         if (ha_len == 0)
 165                 (void)printf("<No address>");
 166         else {
 167                 (void)printf("%s", linkaddr_string(ha, ha_len));
 168                 if (srca_len != 0)
 169                         (void)printf(",%s", linkaddr_string(srca, srca_len));
 170         }
 171 }
 172
 173 static void
 174 atmarp_print(const u_char *bp, u_int length, u_int caplen)
 175 {
 176         const struct atmarp_pkthdr *ap;
 177         u_short pro, hrd, op;
 178
 179         ap = (const struct atmarp_pkthdr *)bp;
 180         TCHECK(*ap);
 181
 182         hrd = ATMHRD(ap);
 183         pro = ATMPRO(ap);
 184         op = ATMOP(ap);
 185
 186         if (!TTEST2(*aar_tpa(ap), ATMTPLN(ap))) {
 187                 (void)printf("truncated-atmarp");
 188                 default_print((const u_char *)ap, length);
 189                 return;
 190         }
 191
 192         if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
 193             ATMSPLN(ap) != 4 || ATMTPLN(ap) != 4) {
 194                 (void)printf("atmarp-#%d for proto #%d (%d/%d) hardware #%d",
 195                                 op, pro, ATMSPLN(ap), ATMTPLN(ap), hrd);
 196                 return;
 197         }
 198         if (pro == ETHERTYPE_TRAIL)
 199                 (void)printf("trailer-");
 200         switch (op) {
 201
 202         case ARPOP_REQUEST:
 203                 (void)printf("arp who-has %s", ipaddr_string(ATMTPA(ap)));
 204                 if (ATMTHLN(ap) != 0) {
 205                         (void)printf(" (");
 206                         atmarp_addr_print(ATMTHA(ap), ATMTHLN(ap),
 207                             ATMTSA(ap), ATMTSLN(ap));
 208                         (void)printf(")");
 209                 }
 210                 (void)printf(" tell %s", ipaddr_string(ATMSPA(ap)));
 211                 break;
 212
 213         case ARPOP_REPLY:
 214                 (void)printf("arp reply %s", ipaddr_string(ATMSPA(ap)));
 215                 (void)printf(" is-at ");
 216                 atmarp_addr_print(ATMSHA(ap), ATMSHLN(ap), ATMSSA(ap),
 217                     ATMSSLN(ap));
 218                 break;
 219
 220         case ARPOP_INVREQUEST:
 221                 (void)printf("invarp who-is ");
 222                 atmarp_addr_print(ATMTHA(ap), ATMTHLN(ap), ATMTSA(ap),
 223                     ATMTSLN(ap));
 224                 (void)printf(" tell ");
 225                 atmarp_addr_print(ATMSHA(ap), ATMSHLN(ap), ATMSSA(ap),
 226                     ATMSSLN(ap));
 227                 break;
 228
 229         case ARPOP_INVREPLY:
 230                 (void)printf("invarp reply ");
 231                 atmarp_addr_print(ATMSHA(ap), ATMSHLN(ap), ATMSSA(ap),
 232                     ATMSSLN(ap));
 233                 (void)printf(" at %s", ipaddr_string(ATMSPA(ap)));
 234                 break;
 235
 236         case ATMARPOP_NAK:
 237                 (void)printf("nak reply for %s",
 238                         ipaddr_string(ATMSPA(ap)));
 239                 break;
 240
 241         default:
 242                 (void)printf("atmarp-#%d", op);
 243                 default_print((const u_char *)ap, caplen);
 244                 return;
 245         }
 246         return;
 247 trunc:
 248         (void)printf("[|atmarp]");
 249 }
 250
 251 void
 252 arp_print(const u_char *bp, u_int length, u_int caplen)
 253 {
 254         const struct arp_pkthdr *ap;
 255         u_short pro, hrd, op;
 256
 257         ap = (const struct arp_pkthdr *)bp;
 258         TCHECK(*ap);
 259         hrd = HRD(ap);
 260         if (hrd == ARPHRD_ATM2225) {
 261                 atmarp_print(bp, length, caplen);
 262                 return;
 263         }
 264         pro = PRO(ap);
 265         op = OP(ap);
 266
 267         if (!TTEST2(*ar_tpa(ap), PLN(ap))) {
 268                 (void)printf("truncated-arp");
 269                 default_print((const u_char *)ap, length);
 270                 return;
 271         }
 272
 273         if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
 274             PLN(ap) != 4 || HLN(ap) == 0) {
 275                 (void)printf("arp-#%d for proto #%d (%d) hardware #%d (%d)",
 276                                 op, pro, PLN(ap), hrd, HLN(ap));
 277                 return;
 278         }
 279         if (pro == ETHERTYPE_TRAIL)
 280                 (void)printf("trailer-");
 281         switch (op) {
 282
 283         case ARPOP_REQUEST:
 284                 (void)printf("arp who-has %s", ipaddr_string(TPA(ap)));
 285                 if (memcmp((const char *)ezero, (const char *)THA(ap), HLN(ap)) != 0)
 286                         (void)printf(" (%s)",
 287                             linkaddr_string(THA(ap), HLN(ap)));
 288                 (void)printf(" tell %s", ipaddr_string(SPA(ap)));
 289                 break;
 290
 291         case ARPOP_REPLY:
 292                 (void)printf("arp reply %s", ipaddr_string(SPA(ap)));
 293                 (void)printf(" is-at %s", linkaddr_string(SHA(ap), HLN(ap)));
 294                 break;
 295
 296         case ARPOP_REVREQUEST:
 297                 (void)printf("rarp who-is %s tell %s",
 298                         linkaddr_string(THA(ap), HLN(ap)),
 299                         linkaddr_string(SHA(ap), HLN(ap)));
 300                 break;
 301
 302         case ARPOP_REVREPLY:
 303                 (void)printf("rarp reply %s at %s",
 304                         linkaddr_string(THA(ap), HLN(ap)),
 305                         ipaddr_string(TPA(ap)));
 306                 break;
 307
 308         case ARPOP_INVREQUEST:
 309                 (void)printf("invarp who-is %s tell %s",
 310                         linkaddr_string(THA(ap), HLN(ap)),
 311                         linkaddr_string(SHA(ap), HLN(ap)));
 312                 break;
 313
 314         case ARPOP_INVREPLY:
 315                 (void)printf("invarp reply %s at %s",
 316                         linkaddr_string(THA(ap), HLN(ap)),
 317                         ipaddr_string(TPA(ap)));
 318                 break;
 319
 320         default:
 321                 (void)printf("arp-#%d", op);
 322                 default_print((const u_char *)ap, caplen);
 323                 return;
 324         }
 325         if (hrd != ARPHRD_ETHER)
 326                 printf(" hardware #%d", hrd);
 327         return;
 328 trunc:
 329         (void)printf("[|arp]");
 330 }