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