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 /* \summary: Address Resolution Protocol (ARP) printer */
  23
  24 #include <config.h>
  25
  26 #include "netdissect-stdinc.h"
  27
  28 #define ND_LONGJMP_FROM_TCHECK
  29 #include "netdissect.h"
  30 #include "addrtoname.h"
  31 #include "ethertype.h"
  32 #include "extract.h"
  33
  34
  35 /*
  36  * Address Resolution Protocol.
  37  *
  38  * See RFC 826 for protocol description.  ARP packets are variable
  39  * in size; the arphdr structure defines the fixed-length portion.
  40  * Protocol type values are the same as those for 10 Mb/s Ethernet.
  41  * It is followed by the variable-sized fields ar_sha, arp_spa,
  42  * arp_tha and arp_tpa in that order, according to the lengths
  43  * specified.  Field names used correspond to RFC 826.
  44  */
  45 struct  arp_pkthdr {
  46         nd_uint16_t ar_hrd;     /* format of hardware address */
  47 #define ARPHRD_ETHER    1       /* ethernet hardware format */
  48 #define ARPHRD_IEEE802  6       /* token-ring hardware format */
  49 #define ARPHRD_ARCNET   7       /* arcnet hardware format */
  50 #define ARPHRD_FRELAY   15      /* frame relay hardware format */
  51 #define ARPHRD_ATM2225  19      /* ATM (RFC 2225) */
  52 #define ARPHRD_STRIP    23      /* Ricochet Starmode Radio hardware format */
  53 #define ARPHRD_IEEE1394 24      /* IEEE 1394 (FireWire) hardware format */
  54 #define ARPHRD_INFINIBAND 32    /* InfiniBand RFC 4391 */
  55         nd_uint16_t ar_pro;     /* format of protocol address */
  56         nd_uint8_t  ar_hln;     /* length of hardware address */
  57         nd_uint8_t  ar_pln;     /* length of protocol address */
  58         nd_uint16_t ar_op;      /* one of: */
  59 #define ARPOP_REQUEST   1       /* request to resolve address */
  60 #define ARPOP_REPLY     2       /* response to previous request */
  61 #define ARPOP_REVREQUEST 3      /* request protocol address given hardware */
  62 #define ARPOP_REVREPLY  4       /* response giving protocol address */
  63 #define ARPOP_INVREQUEST 8      /* request to identify peer */
  64 #define ARPOP_INVREPLY  9       /* response identifying peer */
  65 #define ARPOP_NAK       10      /* NAK - only valid for ATM ARP */
  66
  67 /*
  68  * The remaining fields are variable in size,
  69  * according to the sizes above.
  70  */
  71 #ifdef COMMENT_ONLY
  72         nd_byte         ar_sha[];       /* sender hardware address */
  73         nd_byte         ar_spa[];       /* sender protocol address */
  74         nd_byte         ar_tha[];       /* target hardware address */
  75         nd_byte         ar_tpa[];       /* target protocol address */
  76 #endif
  77 #define ar_sha(ap)      (((const u_char *)((ap)+1))+  0)
  78 #define ar_spa(ap)      (((const u_char *)((ap)+1))+  GET_U_1((ap)->ar_hln))
  79 #define ar_tha(ap)      (((const u_char *)((ap)+1))+  GET_U_1((ap)->ar_hln)+GET_U_1((ap)->ar_pln))
  80 #define ar_tpa(ap)      (((const u_char *)((ap)+1))+2*GET_U_1((ap)->ar_hln)+GET_U_1((ap)->ar_pln))
  81 };
  82
  83 #define ARP_HDRLEN      8
  84
  85 #define HRD(ap) GET_BE_U_2((ap)->ar_hrd)
  86 #define HRD_LEN(ap) GET_U_1((ap)->ar_hln)
  87 #define PROTO_LEN(ap) GET_U_1((ap)->ar_pln)
  88 #define OP(ap)  GET_BE_U_2((ap)->ar_op)
  89 #define PRO(ap) GET_BE_U_2((ap)->ar_pro)
  90 #define SHA(ap) (ar_sha(ap))
  91 #define SPA(ap) (ar_spa(ap))
  92 #define THA(ap) (ar_tha(ap))
  93 #define TPA(ap) (ar_tpa(ap))
  94
  95
  96 static const struct tok arpop_values[] = {
  97     { ARPOP_REQUEST, "Request" },
  98     { ARPOP_REPLY, "Reply" },
  99     { ARPOP_REVREQUEST, "Reverse Request" },
 100     { ARPOP_REVREPLY, "Reverse Reply" },
 101     { ARPOP_INVREQUEST, "Inverse Request" },
 102     { ARPOP_INVREPLY, "Inverse Reply" },
 103     { ARPOP_NAK, "NACK Reply" },
 104     { 0, NULL }
 105 };
 106
 107 static const struct tok arphrd_values[] = {
 108     { ARPHRD_ETHER, "Ethernet" },
 109     { ARPHRD_IEEE802, "TokenRing" },
 110     { ARPHRD_ARCNET, "ArcNet" },
 111     { ARPHRD_FRELAY, "FrameRelay" },
 112     { ARPHRD_STRIP, "Strip" },
 113     { ARPHRD_IEEE1394, "IEEE 1394" },
 114     { ARPHRD_ATM2225, "ATM" },
 115     { ARPHRD_INFINIBAND, "InfiniBand" },
 116     { 0, NULL }
 117 };
 118
 119 /*
 120  * ATM Address Resolution Protocol.
 121  *
 122  * See RFC 2225 for protocol description.  ATMARP packets are similar
 123  * to ARP packets, except that there are no length fields for the
 124  * protocol address - instead, there are type/length fields for
 125  * the ATM number and subaddress - and the hardware addresses consist
 126  * of an ATM number and an ATM subaddress.
 127  */
 128 struct  atmarp_pkthdr {
 129         nd_uint16_t aar_hrd;    /* format of hardware address */
 130         nd_uint16_t aar_pro;    /* format of protocol address */
 131         nd_uint8_t  aar_shtl;   /* length of source ATM number */
 132         nd_uint8_t  aar_sstl;   /* length of source ATM subaddress */
 133 #define ATMARP_IS_E164  0x40    /* bit in type/length for E.164 format */
 134 #define ATMARP_LEN_MASK 0x3F    /* length of {sub}address in type/length */
 135         nd_uint16_t aar_op;     /* same as regular ARP */
 136         nd_uint8_t  aar_spln;   /* length of source protocol address */
 137         nd_uint8_t  aar_thtl;   /* length of target ATM number */
 138         nd_uint8_t  aar_tstl;   /* length of target ATM subaddress */
 139         nd_uint8_t  aar_tpln;   /* length of target protocol address */
 140 /*
 141  * The remaining fields are variable in size,
 142  * according to the sizes above.
 143  */
 144 #ifdef COMMENT_ONLY
 145         nd_byte         aar_sha[];      /* source ATM number */
 146         nd_byte         aar_ssa[];      /* source ATM subaddress */
 147         nd_byte         aar_spa[];      /* sender protocol address */
 148         nd_byte         aar_tha[];      /* target ATM number */
 149         nd_byte         aar_tsa[];      /* target ATM subaddress */
 150         nd_byte         aar_tpa[];      /* target protocol address */
 151 #endif
 152
 153 #define ATMHRD(ap)  GET_BE_U_2((ap)->aar_hrd)
 154 #define ATMSHRD_LEN(ap) (GET_U_1((ap)->aar_shtl) & ATMARP_LEN_MASK)
 155 #define ATMSSLN(ap) (GET_U_1((ap)->aar_sstl) & ATMARP_LEN_MASK)
 156 #define ATMSPROTO_LEN(ap) GET_U_1((ap)->aar_spln)
 157 #define ATMOP(ap)   GET_BE_U_2((ap)->aar_op)
 158 #define ATMPRO(ap)  GET_BE_U_2((ap)->aar_pro)
 159 #define ATMTHRD_LEN(ap) (GET_U_1((ap)->aar_thtl) & ATMARP_LEN_MASK)
 160 #define ATMTSLN(ap) (GET_U_1((ap)->aar_tstl) & ATMARP_LEN_MASK)
 161 #define ATMTPROTO_LEN(ap) GET_U_1((ap)->aar_tpln)
 162 #define aar_sha(ap)     ((const u_char *)((ap)+1))
 163 #define aar_ssa(ap)     (aar_sha(ap) + ATMSHRD_LEN(ap))
 164 #define aar_spa(ap)     (aar_ssa(ap) + ATMSSLN(ap))
 165 #define aar_tha(ap)     (aar_spa(ap) + ATMSPROTO_LEN(ap))
 166 #define aar_tsa(ap)     (aar_tha(ap) + ATMTHRD_LEN(ap))
 167 #define aar_tpa(ap)     (aar_tsa(ap) + ATMTSLN(ap))
 168 };
 169
 170 #define ATMSHA(ap) (aar_sha(ap))
 171 #define ATMSSA(ap) (aar_ssa(ap))
 172 #define ATMSPA(ap) (aar_spa(ap))
 173 #define ATMTHA(ap) (aar_tha(ap))
 174 #define ATMTSA(ap) (aar_tsa(ap))
 175 #define ATMTPA(ap) (aar_tpa(ap))
 176
 177 static int
 178 isnonzero(netdissect_options *ndo, const u_char *a, size_t len)
 179 {
 180         while (len != 0) {
 181                 if (GET_U_1(a) != 0)
 182                         return (1);
 183                 a++;
 184                 len--;
 185         }
 186         return (0);
 187 }
 188
 189 static void
 190 tpaddr_print_ip(netdissect_options *ndo,
 191                 const struct arp_pkthdr *ap, u_short pro)
 192 {
 193         if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
 194                 ND_PRINT("<wrong proto type>");
 195         else if (PROTO_LEN(ap) != 4)
 196                 ND_PRINT("<wrong len>");
 197         else
 198                 ND_PRINT("%s", GET_IPADDR_STRING(TPA(ap)));
 199 }
 200
 201 static void
 202 spaddr_print_ip(netdissect_options *ndo,
 203                 const struct arp_pkthdr *ap, u_short pro)
 204 {
 205         if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
 206                 ND_PRINT("<wrong proto type>");
 207         else if (PROTO_LEN(ap) != 4)
 208                 ND_PRINT("<wrong len>");
 209         else
 210                 ND_PRINT("%s", GET_IPADDR_STRING(SPA(ap)));
 211 }
 212
 213 static void
 214 atmarp_addr_print(netdissect_options *ndo,
 215                   const u_char *ha, u_int ha_len, const u_char *srca,
 216     u_int srca_len)
 217 {
 218         if (ha_len == 0)
 219                 ND_PRINT("<No address>");
 220         else {
 221                 ND_PRINT("%s", GET_LINKADDR_STRING(ha, LINKADDR_ATM, ha_len));
 222                 if (srca_len != 0)
 223                         ND_PRINT(",%s",
 224                                   GET_LINKADDR_STRING(srca, LINKADDR_ATM, srca_len));
 225         }
 226 }
 227
 228 static void
 229 atmarp_tpaddr_print(netdissect_options *ndo,
 230                     const struct atmarp_pkthdr *ap, u_short pro)
 231 {
 232         if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
 233                 ND_PRINT("<wrong proto type>");
 234         else if (ATMTPROTO_LEN(ap) != 4)
 235                 ND_PRINT("<wrong tplen>");
 236         else
 237                 ND_PRINT("%s", GET_IPADDR_STRING(ATMTPA(ap)));
 238 }
 239
 240 static void
 241 atmarp_spaddr_print(netdissect_options *ndo,
 242                     const struct atmarp_pkthdr *ap, u_short pro)
 243 {
 244         if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
 245                 ND_PRINT("<wrong proto type>");
 246         else if (ATMSPROTO_LEN(ap) != 4)
 247                 ND_PRINT("<wrong splen>");
 248         else
 249                 ND_PRINT("%s", GET_IPADDR_STRING(ATMSPA(ap)));
 250 }
 251
 252 static void
 253 atmarp_print(netdissect_options *ndo,
 254              const u_char *bp, u_int length, u_int caplen)
 255 {
 256         const struct atmarp_pkthdr *ap;
 257         u_short pro, hrd, op;
 258
 259         ap = (const struct atmarp_pkthdr *)bp;
 260         ND_TCHECK_SIZE(ap);
 261
 262         hrd = ATMHRD(ap);
 263         pro = ATMPRO(ap);
 264         op = ATMOP(ap);
 265
 266         ND_TCHECK_LEN(ATMTPA(ap), ATMTPROTO_LEN(ap));
 267
 268         if (!ndo->ndo_eflag) {
 269             ND_PRINT("ARP, ");
 270         }
 271
 272         if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
 273             ATMSPROTO_LEN(ap) != 4 ||
 274             ATMTPROTO_LEN(ap) != 4 ||
 275             ndo->ndo_vflag) {
 276                 ND_PRINT("%s, %s (len %u/%u)",
 277                           tok2str(arphrd_values, "Unknown Hardware (%u)", hrd),
 278                           tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro),
 279                           ATMSPROTO_LEN(ap),
 280                           ATMTPROTO_LEN(ap));
 281
 282                 /* don't know about the address formats */
 283                 if (!ndo->ndo_vflag) {
 284                     goto out;
 285                 }
 286         }
 287
 288         /* print operation */
 289         ND_PRINT("%s%s ",
 290                ndo->ndo_vflag ? ", " : "",
 291                tok2str(arpop_values, "Unknown (%u)", op));
 292
 293         switch (op) {
 294
 295         case ARPOP_REQUEST:
 296                 ND_PRINT("who-has ");
 297                 atmarp_tpaddr_print(ndo, ap, pro);
 298                 if (ATMTHRD_LEN(ap) != 0) {
 299                         ND_PRINT(" (");
 300                         atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap),
 301                             ATMTSA(ap), ATMTSLN(ap));
 302                         ND_PRINT(")");
 303                 }
 304                 ND_PRINT(" tell ");
 305                 atmarp_spaddr_print(ndo, ap, pro);
 306                 break;
 307
 308         case ARPOP_REPLY:
 309                 atmarp_spaddr_print(ndo, ap, pro);
 310                 ND_PRINT(" is-at ");
 311                 atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
 312                                   ATMSSLN(ap));
 313                 break;
 314
 315         case ARPOP_INVREQUEST:
 316                 ND_PRINT("who-is ");
 317                 atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap), ATMTSA(ap),
 318                     ATMTSLN(ap));
 319                 ND_PRINT(" tell ");
 320                 atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
 321                     ATMSSLN(ap));
 322                 break;
 323
 324         case ARPOP_INVREPLY:
 325                 atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
 326                     ATMSSLN(ap));
 327                 ND_PRINT("at ");
 328                 atmarp_spaddr_print(ndo, ap, pro);
 329                 break;
 330
 331         case ARPOP_NAK:
 332                 ND_PRINT("for ");
 333                 atmarp_spaddr_print(ndo, ap, pro);
 334                 break;
 335
 336         default:
 337                 ND_DEFAULTPRINT((const u_char *)ap, caplen);
 338                 return;
 339         }
 340
 341  out:
 342         ND_PRINT(", length %u", length);
 343 }
 344
 345 void
 346 arp_print(netdissect_options *ndo,
 347           const u_char *bp, u_int length, u_int caplen)
 348 {
 349         const struct arp_pkthdr *ap;
 350         u_short pro, hrd, op, linkaddr;
 351
 352         ndo->ndo_protocol = "arp";
 353         ap = (const struct arp_pkthdr *)bp;
 354         ND_TCHECK_SIZE(ap);
 355
 356         hrd = HRD(ap);
 357         pro = PRO(ap);
 358         op = OP(ap);
 359
 360
 361         /* if its ATM then call the ATM ARP printer
 362            for Frame-relay ARP most of the fields
 363            are similar to Ethernet so overload the Ethernet Printer
 364            and set the linkaddr type for GET_LINKADDR_STRING() accordingly */
 365
 366         switch(hrd) {
 367         case ARPHRD_ATM2225:
 368             atmarp_print(ndo, bp, length, caplen);
 369             return;
 370         case ARPHRD_FRELAY:
 371             linkaddr = LINKADDR_FRELAY;
 372             break;
 373         default:
 374             linkaddr = LINKADDR_MAC48;
 375             break;
 376         }
 377
 378         ND_TCHECK_LEN(TPA(ap), PROTO_LEN(ap));
 379
 380         if (!ndo->ndo_eflag) {
 381             ND_PRINT("ARP, ");
 382         }
 383
 384         /* print hardware type/len and proto type/len */
 385         if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
 386             PROTO_LEN(ap) != 4 ||
 387             HRD_LEN(ap) == 0 ||
 388             ndo->ndo_vflag) {
 389             ND_PRINT("%s (len %u), %s (len %u)",
 390                       tok2str(arphrd_values, "Unknown Hardware (%u)", hrd),
 391                       HRD_LEN(ap),
 392                       tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro),
 393                       PROTO_LEN(ap));
 394
 395             /* don't know about the address formats */
 396             if (!ndo->ndo_vflag) {
 397                 goto out;
 398             }
 399         }
 400
 401         /* print operation */
 402         ND_PRINT("%s%s ",
 403                ndo->ndo_vflag ? ", " : "",
 404                tok2str(arpop_values, "Unknown (%u)", op));
 405
 406         switch (op) {
 407
 408         case ARPOP_REQUEST:
 409                 ND_PRINT("who-has ");
 410                 tpaddr_print_ip(ndo, ap, pro);
 411                 if (isnonzero(ndo, (const u_char *)THA(ap), HRD_LEN(ap)))
 412                         ND_PRINT(" (%s)",
 413                                   GET_LINKADDR_STRING(THA(ap), linkaddr, HRD_LEN(ap)));
 414                 ND_PRINT(" tell ");
 415                 spaddr_print_ip(ndo, ap, pro);
 416                 break;
 417
 418         case ARPOP_REPLY:
 419                 spaddr_print_ip(ndo, ap, pro);
 420                 ND_PRINT(" is-at %s",
 421                           GET_LINKADDR_STRING(SHA(ap), linkaddr, HRD_LEN(ap)));
 422                 break;
 423
 424         case ARPOP_REVREQUEST:
 425                 /*
 426                  * XXX - GET_LINKADDR_STRING() may return a pointer to
 427                  * a static buffer, so we only have one call to it per
 428                  * ND_PRINT() call.
 429                  *
 430                  * This should be done in a cleaner fashion.
 431                  */
 432                 ND_PRINT("who-is %s",
 433                           GET_LINKADDR_STRING(THA(ap), linkaddr, HRD_LEN(ap)));
 434                 ND_PRINT(" tell %s",
 435                           GET_LINKADDR_STRING(SHA(ap), linkaddr, HRD_LEN(ap)));
 436                 break;
 437
 438         case ARPOP_REVREPLY:
 439                 ND_PRINT("%s at ",
 440                           GET_LINKADDR_STRING(THA(ap), linkaddr, HRD_LEN(ap)));
 441                 tpaddr_print_ip(ndo, ap, pro);
 442                 break;
 443
 444         case ARPOP_INVREQUEST:
 445                 /*
 446                  * XXX - GET_LINKADDR_STRING() may return a pointer to
 447                  * a static buffer, so we only have one call to it per
 448                  * ND_PRINT() call.
 449                  *
 450                  * This should be done in a cleaner fashion.
 451                  */
 452                 ND_PRINT("who-is %s",
 453                           GET_LINKADDR_STRING(THA(ap), linkaddr, HRD_LEN(ap)));
 454                 ND_PRINT(" tell %s",
 455                           GET_LINKADDR_STRING(SHA(ap), linkaddr, HRD_LEN(ap)));
 456                 break;
 457
 458         case ARPOP_INVREPLY:
 459                 ND_PRINT("%s at ",
 460                           GET_LINKADDR_STRING(SHA(ap), linkaddr, HRD_LEN(ap)));
 461                 spaddr_print_ip(ndo, ap, pro);
 462                 break;
 463
 464         default:
 465                 ND_DEFAULTPRINT((const u_char *)ap, caplen);
 466                 return;
 467         }
 468
 469  out:
 470         ND_PRINT(", length %u", length);
 471 }