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 #ifdef HAVE_CONFIG_H
  23 #include "config.h"
  24 #endif
  25
  26 #include <tcpdump-stdinc.h>
  27
  28 #include <string.h>
  29
  30 #include "netdissect.h"
  31 #include "addrtoname.h"
  32 #include "ether.h"
  33 #include "ethertype.h"
  34 #include "extract.h"
  35
  36 static const char tstr[] = "[|ARP]";
  37
  38 /*
  39  * Address Resolution Protocol.
  40  *
  41  * See RFC 826 for protocol description.  ARP packets are variable
  42  * in size; the arphdr structure defines the fixed-length portion.
  43  * Protocol type values are the same as those for 10 Mb/s Ethernet.
  44  * It is followed by the variable-sized fields ar_sha, arp_spa,
  45  * arp_tha and arp_tpa in that order, according to the lengths
  46  * specified.  Field names used correspond to RFC 826.
  47  */
  48 struct  arp_pkthdr {
  49         u_short ar_hrd;         /* format of hardware address */
  50 #define ARPHRD_ETHER    1       /* ethernet hardware format */
  51 #define ARPHRD_IEEE802  6       /* token-ring hardware format */
  52 #define ARPHRD_ARCNET   7       /* arcnet hardware format */
  53 #define ARPHRD_FRELAY   15      /* frame relay hardware format */
  54 #define ARPHRD_ATM2225  19      /* ATM (RFC 2225) */
  55 #define ARPHRD_STRIP    23      /* Ricochet Starmode Radio hardware format */
  56 #define ARPHRD_IEEE1394 24      /* IEEE 1394 (FireWire) hardware format */
  57         u_short ar_pro;         /* format of protocol address */
  58         u_char  ar_hln;         /* length of hardware address */
  59         u_char  ar_pln;         /* length of protocol address */
  60         u_short ar_op;          /* one of: */
  61 #define ARPOP_REQUEST   1       /* request to resolve address */
  62 #define ARPOP_REPLY     2       /* response to previous request */
  63 #define ARPOP_REVREQUEST 3      /* request protocol address given hardware */
  64 #define ARPOP_REVREPLY  4       /* response giving protocol address */
  65 #define ARPOP_INVREQUEST 8      /* request to identify peer */
  66 #define ARPOP_INVREPLY  9       /* response identifying peer */
  67 #define ARPOP_NAK       10      /* NAK - only valif for ATM ARP */
  68
  69 /*
  70  * The remaining fields are variable in size,
  71  * according to the sizes above.
  72  */
  73 #ifdef COMMENT_ONLY
  74         u_char  ar_sha[];       /* sender hardware address */
  75         u_char  ar_spa[];       /* sender protocol address */
  76         u_char  ar_tha[];       /* target hardware address */
  77         u_char  ar_tpa[];       /* target protocol address */
  78 #endif
  79 #define ar_sha(ap)      (((const u_char *)((ap)+1))+0)
  80 #define ar_spa(ap)      (((const u_char *)((ap)+1))+  (ap)->ar_hln)
  81 #define ar_tha(ap)      (((const u_char *)((ap)+1))+  (ap)->ar_hln+(ap)->ar_pln)
  82 #define ar_tpa(ap)      (((const u_char *)((ap)+1))+2*(ap)->ar_hln+(ap)->ar_pln)
  83 };
  84
  85 #define ARP_HDRLEN      8
  86
  87 #define HRD(ap) EXTRACT_16BITS(&(ap)->ar_hrd)
  88 #define HRD_LEN(ap) ((ap)->ar_hln)
  89 #define PROTO_LEN(ap) ((ap)->ar_pln)
  90 #define OP(ap)  EXTRACT_16BITS(&(ap)->ar_op)
  91 #define PRO(ap) EXTRACT_16BITS(&(ap)->ar_pro)
  92 #define SHA(ap) (ar_sha(ap))
  93 #define SPA(ap) (ar_spa(ap))
  94 #define THA(ap) (ar_tha(ap))
  95 #define TPA(ap) (ar_tpa(ap))
  96
  97
  98 static const struct tok arpop_values[] = {
  99     { ARPOP_REQUEST, "Request" },
 100     { ARPOP_REPLY, "Reply" },
 101     { ARPOP_REVREQUEST, "Reverse Request" },
 102     { ARPOP_REVREPLY, "Reverse Reply" },
 103     { ARPOP_INVREQUEST, "Inverse Request" },
 104     { ARPOP_INVREPLY, "Inverse Reply" },
 105     { ARPOP_NAK, "NACK Reply" },
 106     { 0, NULL }
 107 };
 108
 109 static const struct tok arphrd_values[] = {
 110     { ARPHRD_ETHER, "Ethernet" },
 111     { ARPHRD_IEEE802, "TokenRing" },
 112     { ARPHRD_ARCNET, "ArcNet" },
 113     { ARPHRD_FRELAY, "FrameRelay" },
 114     { ARPHRD_STRIP, "Strip" },
 115     { ARPHRD_IEEE1394, "IEEE 1394" },
 116     { ARPHRD_ATM2225, "ATM" },
 117     { 0, NULL }
 118 };
 119
 120 /*
 121  * ATM Address Resolution Protocol.
 122  *
 123  * See RFC 2225 for protocol description.  ATMARP packets are similar
 124  * to ARP packets, except that there are no length fields for the
 125  * protocol address - instead, there are type/length fields for
 126  * the ATM number and subaddress - and the hardware addresses consist
 127  * of an ATM number and an ATM subaddress.
 128  */
 129 struct  atmarp_pkthdr {
 130         u_short aar_hrd;        /* format of hardware address */
 131         u_short aar_pro;        /* format of protocol address */
 132         u_char  aar_shtl;       /* length of source ATM number */
 133         u_char  aar_sstl;       /* length of source ATM subaddress */
 134 #define ATMARP_IS_E164  0x40    /* bit in type/length for E.164 format */
 135 #define ATMARP_LEN_MASK 0x3F    /* length of {sub}address in type/length */
 136         u_short aar_op;         /* same as regular ARP */
 137         u_char  aar_spln;       /* length of source protocol address */
 138         u_char  aar_thtl;       /* length of target ATM number */
 139         u_char  aar_tstl;       /* length of target ATM subaddress */
 140         u_char  aar_tpln;       /* length of target protocol address */
 141 /*
 142  * The remaining fields are variable in size,
 143  * according to the sizes above.
 144  */
 145 #ifdef COMMENT_ONLY
 146         u_char  aar_sha[];      /* source ATM number */
 147         u_char  aar_ssa[];      /* source ATM subaddress */
 148         u_char  aar_spa[];      /* sender protocol address */
 149         u_char  aar_tha[];      /* target ATM number */
 150         u_char  aar_tsa[];      /* target ATM subaddress */
 151         u_char  aar_tpa[];      /* target protocol address */
 152 #endif
 153
 154 #define ATMHRD(ap)  EXTRACT_16BITS(&(ap)->aar_hrd)
 155 #define ATMSHRD_LEN(ap) ((ap)->aar_shtl & ATMARP_LEN_MASK)
 156 #define ATMSSLN(ap) ((ap)->aar_sstl & ATMARP_LEN_MASK)
 157 #define ATMSPROTO_LEN(ap) ((ap)->aar_spln)
 158 #define ATMOP(ap)   EXTRACT_16BITS(&(ap)->aar_op)
 159 #define ATMPRO(ap)  EXTRACT_16BITS(&(ap)->aar_pro)
 160 #define ATMTHRD_LEN(ap) ((ap)->aar_thtl & ATMARP_LEN_MASK)
 161 #define ATMTSLN(ap) ((ap)->aar_tstl & ATMARP_LEN_MASK)
 162 #define ATMTPROTO_LEN(ap) ((ap)->aar_tpln)
 163 #define aar_sha(ap)     ((const u_char *)((ap)+1))
 164 #define aar_ssa(ap)     (aar_sha(ap) + ATMSHRD_LEN(ap))
 165 #define aar_spa(ap)     (aar_ssa(ap) + ATMSSLN(ap))
 166 #define aar_tha(ap)     (aar_spa(ap) + ATMSPROTO_LEN(ap))
 167 #define aar_tsa(ap)     (aar_tha(ap) + ATMTHRD_LEN(ap))
 168 #define aar_tpa(ap)     (aar_tsa(ap) + ATMTSLN(ap))
 169 };
 170
 171 #define ATMSHA(ap) (aar_sha(ap))
 172 #define ATMSSA(ap) (aar_ssa(ap))
 173 #define ATMSPA(ap) (aar_spa(ap))
 174 #define ATMTHA(ap) (aar_tha(ap))
 175 #define ATMTSA(ap) (aar_tsa(ap))
 176 #define ATMTPA(ap) (aar_tpa(ap))
 177
 178 static u_char ezero[6];
 179
 180 static void
 181 atmarp_addr_print(netdissect_options *ndo,
 182                   const u_char *ha, u_int ha_len, const u_char *srca,
 183     u_int srca_len)
 184 {
 185         if (ha_len == 0)
 186                 ND_PRINT((ndo, "<No address>"));
 187         else {
 188                 ND_PRINT((ndo, "%s", linkaddr_string(ndo, ha, LINKADDR_ATM, ha_len)));
 189                 if (srca_len != 0)
 190                         ND_PRINT((ndo, ",%s",
 191                                   linkaddr_string(ndo, srca, LINKADDR_ATM, srca_len)));
 192         }
 193 }
 194
 195 static void
 196 atmarp_print(netdissect_options *ndo,
 197              const u_char *bp, u_int length, u_int caplen)
 198 {
 199         const struct atmarp_pkthdr *ap;
 200         u_short pro, hrd, op;
 201
 202         ap = (const struct atmarp_pkthdr *)bp;
 203         ND_TCHECK(*ap);
 204
 205         hrd = ATMHRD(ap);
 206         pro = ATMPRO(ap);
 207         op = ATMOP(ap);
 208
 209         if (!ND_TTEST2(*aar_tpa(ap), ATMTPROTO_LEN(ap))) {
 210                 ND_PRINT((ndo, "%s", tstr));
 211                 ND_DEFAULTPRINT((const u_char *)ap, length);
 212                 return;
 213         }
 214
 215         if (!ndo->ndo_eflag) {
 216             ND_PRINT((ndo, "ARP, "));
 217         }
 218
 219         if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
 220             ATMSPROTO_LEN(ap) != 4 ||
 221             ATMTPROTO_LEN(ap) != 4 ||
 222             ndo->ndo_vflag) {
 223                 ND_PRINT((ndo, "%s, %s (len %u/%u)",
 224                           tok2str(arphrd_values, "Unknown Hardware (%u)", hrd),
 225                           tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro),
 226                           ATMSPROTO_LEN(ap),
 227                           ATMTPROTO_LEN(ap)));
 228
 229                 /* don't know know about the address formats */
 230                 if (!ndo->ndo_vflag) {
 231                     goto out;
 232                 }
 233         }
 234
 235         /* print operation */
 236         ND_PRINT((ndo, "%s%s ",
 237                ndo->ndo_vflag ? ", " : "",
 238                tok2str(arpop_values, "Unknown (%u)", op)));
 239
 240         switch (op) {
 241
 242         case ARPOP_REQUEST:
 243                 ND_PRINT((ndo, "who-has %s", ipaddr_string(ndo, ATMTPA(ap))));
 244                 if (ATMTHRD_LEN(ap) != 0) {
 245                         ND_PRINT((ndo, " ("));
 246                         atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap),
 247                             ATMTSA(ap), ATMTSLN(ap));
 248                         ND_PRINT((ndo, ")"));
 249                 }
 250                 ND_PRINT((ndo, "tell %s", ipaddr_string(ndo, ATMSPA(ap))));
 251                 break;
 252
 253         case ARPOP_REPLY:
 254                 ND_PRINT((ndo, "%s is-at ", ipaddr_string(ndo, ATMSPA(ap))));
 255                 atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
 256                                   ATMSSLN(ap));
 257                 break;
 258
 259         case ARPOP_INVREQUEST:
 260                 ND_PRINT((ndo, "who-is "));
 261                 atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap), ATMTSA(ap),
 262                     ATMTSLN(ap));
 263                 ND_PRINT((ndo, " tell "));
 264                 atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
 265                     ATMSSLN(ap));
 266                 break;
 267
 268         case ARPOP_INVREPLY:
 269                 atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
 270                     ATMSSLN(ap));
 271                 ND_PRINT((ndo, "at %s", ipaddr_string(ndo, ATMSPA(ap))));
 272                 break;
 273
 274         case ARPOP_NAK:
 275                 ND_PRINT((ndo, "for %s", ipaddr_string(ndo, ATMSPA(ap))));
 276                 break;
 277
 278         default:
 279                 ND_DEFAULTPRINT((const u_char *)ap, caplen);
 280                 return;
 281         }
 282
 283  out:
 284         ND_PRINT((ndo, ", length %u", length));
 285         return;
 286
 287 trunc:
 288         ND_PRINT((ndo, "%s", tstr));
 289 }
 290
 291 void
 292 arp_print(netdissect_options *ndo,
 293           const u_char *bp, u_int length, u_int caplen)
 294 {
 295         const struct arp_pkthdr *ap;
 296         u_short pro, hrd, op, linkaddr;
 297
 298         ap = (const struct arp_pkthdr *)bp;
 299         ND_TCHECK(*ap);
 300
 301         hrd = HRD(ap);
 302         pro = PRO(ap);
 303         op = OP(ap);
 304
 305
 306         /* if its ATM then call the ATM ARP printer
 307            for Frame-relay ARP most of the fields
 308            are similar to Ethernet so overload the Ethernet Printer
 309            and set the linkaddr type for linkaddr_string(ndo, ) accordingly */
 310
 311         switch(hrd) {
 312         case ARPHRD_ATM2225:
 313             atmarp_print(ndo, bp, length, caplen);
 314             return;
 315         case ARPHRD_FRELAY:
 316             linkaddr = LINKADDR_FRELAY;
 317             break;
 318         default:
 319             linkaddr = LINKADDR_ETHER;
 320             break;
 321         }
 322
 323         if (!ND_TTEST2(*ar_tpa(ap), PROTO_LEN(ap))) {
 324                 ND_PRINT((ndo, "%s", tstr));
 325                 ND_DEFAULTPRINT((const u_char *)ap, length);
 326                 return;
 327         }
 328
 329         if (!ndo->ndo_eflag) {
 330             ND_PRINT((ndo, "ARP, "));
 331         }
 332
 333         /* print hardware type/len and proto type/len */
 334         if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
 335             PROTO_LEN(ap) != 4 ||
 336             HRD_LEN(ap) == 0 ||
 337             ndo->ndo_vflag) {
 338             ND_PRINT((ndo, "%s (len %u), %s (len %u)",
 339                       tok2str(arphrd_values, "Unknown Hardware (%u)", hrd),
 340                       HRD_LEN(ap),
 341                       tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro),
 342                       PROTO_LEN(ap)));
 343
 344             /* don't know know about the address formats */
 345             if (!ndo->ndo_vflag) {
 346                 goto out;
 347             }
 348         }
 349
 350         /* print operation */
 351         ND_PRINT((ndo, "%s%s ",
 352                ndo->ndo_vflag ? ", " : "",
 353                tok2str(arpop_values, "Unknown (%u)", op)));
 354
 355         switch (op) {
 356
 357         case ARPOP_REQUEST:
 358                 ND_PRINT((ndo, "who-has %s", ipaddr_string(ndo, TPA(ap))));
 359                 if (memcmp((const char *)ezero, (const char *)THA(ap), HRD_LEN(ap)) != 0)
 360                         ND_PRINT((ndo, " (%s)",
 361                                   linkaddr_string(ndo, THA(ap), linkaddr, HRD_LEN(ap))));
 362                 ND_PRINT((ndo, " tell %s", ipaddr_string(ndo, SPA(ap))));
 363                 break;
 364
 365         case ARPOP_REPLY:
 366                 ND_PRINT((ndo, "%s is-at %s",
 367                           ipaddr_string(ndo, SPA(ap)),
 368                           linkaddr_string(ndo, SHA(ap), linkaddr, HRD_LEN(ap))));
 369                 break;
 370
 371         case ARPOP_REVREQUEST:
 372                 ND_PRINT((ndo, "who-is %s tell %s",
 373                           linkaddr_string(ndo, THA(ap), linkaddr, HRD_LEN(ap)),
 374                           linkaddr_string(ndo, SHA(ap), linkaddr, HRD_LEN(ap))));
 375                 break;
 376
 377         case ARPOP_REVREPLY:
 378                 ND_PRINT((ndo, "%s at %s",
 379                           linkaddr_string(ndo, THA(ap), linkaddr, HRD_LEN(ap)),
 380                           ipaddr_string(ndo, TPA(ap))));
 381                 break;
 382
 383         case ARPOP_INVREQUEST:
 384                 ND_PRINT((ndo, "who-is %s tell %s",
 385                           linkaddr_string(ndo, THA(ap), linkaddr, HRD_LEN(ap)),
 386                           linkaddr_string(ndo, SHA(ap), linkaddr, HRD_LEN(ap))));
 387                 break;
 388
 389         case ARPOP_INVREPLY:
 390                 ND_PRINT((ndo,"%s at %s",
 391                           linkaddr_string(ndo, SHA(ap), linkaddr, HRD_LEN(ap)),
 392                           ipaddr_string(ndo, SPA(ap))));
 393                 break;
 394
 395         default:
 396                 ND_DEFAULTPRINT((const u_char *)ap, caplen);
 397                 return;
 398         }
 399
 400  out:
 401         ND_PRINT((ndo, ", length %u", length));
 402
 403         return;
 404 trunc:
 405         ND_PRINT((ndo, "%s", tstr));
 406 }
 407
 408 /*
 409  * Local Variables:
 410  * c-style: bsd
 411  * End:
 412  */
 413