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 #include <sys/cdefs.h> 23 #ifndef lint 24 __RCSID("$NetBSD: print-arp.c,v 1.11 2024/09/02 16:15:30 christos Exp $"); 25 #endif 26 27 /* \summary: Address Resolution Protocol (ARP) printer */ 28 29 #include <config.h> 30 31 #include "netdissect-stdinc.h" 32 33 #define ND_LONGJMP_FROM_TCHECK 34 #include "netdissect.h" 35 #include "addrtoname.h" 36 #include "ethertype.h" 37 #include "extract.h" 38 39 40 /* 41 * Address Resolution Protocol. 42 * 43 * See RFC 826 for protocol description. ARP packets are variable 44 * in size; the arphdr structure defines the fixed-length portion. 45 * Protocol type values are the same as those for 10 Mb/s Ethernet. 46 * It is followed by the variable-sized fields ar_sha, arp_spa, 47 * arp_tha and arp_tpa in that order, according to the lengths 48 * specified. Field names used correspond to RFC 826. 49 */ 50 struct arp_pkthdr { 51 nd_uint16_t ar_hrd; /* format of hardware address */ 52 #define ARPHRD_ETHER 1 /* ethernet hardware format */ 53 #define ARPHRD_IEEE802 6 /* token-ring hardware format */ 54 #define ARPHRD_ARCNET 7 /* arcnet hardware format */ 55 #define ARPHRD_FRELAY 15 /* frame relay hardware format */ 56 #define ARPHRD_ATM2225 19 /* ATM (RFC 2225) */ 57 #define ARPHRD_STRIP 23 /* Ricochet Starmode Radio hardware format */ 58 #define ARPHRD_IEEE1394 24 /* IEEE 1394 (FireWire) hardware format */ 59 #define ARPHRD_INFINIBAND 32 /* InfiniBand RFC 4391 */ 60 nd_uint16_t ar_pro; /* format of protocol address */ 61 nd_uint8_t ar_hln; /* length of hardware address */ 62 nd_uint8_t ar_pln; /* length of protocol address */ 63 nd_uint16_t 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 #define ARPOP_NAK 10 /* NAK - only valid for ATM ARP */ 71 72 /* 73 * The remaining fields are variable in size, 74 * according to the sizes above. 75 */ 76 #ifdef COMMENT_ONLY 77 nd_byte ar_sha[]; /* sender hardware address */ 78 nd_byte ar_spa[]; /* sender protocol address */ 79 nd_byte ar_tha[]; /* target hardware address */ 80 nd_byte ar_tpa[]; /* target protocol address */ 81 #endif 82 #define ar_sha(ap) (((const u_char *)((ap)+1))+ 0) 83 #define ar_spa(ap) (((const u_char *)((ap)+1))+ GET_U_1((ap)->ar_hln)) 84 #define ar_tha(ap) (((const u_char *)((ap)+1))+ GET_U_1((ap)->ar_hln)+GET_U_1((ap)->ar_pln)) 85 #define ar_tpa(ap) (((const u_char *)((ap)+1))+2*GET_U_1((ap)->ar_hln)+GET_U_1((ap)->ar_pln)) 86 }; 87 88 #define ARP_HDRLEN 8 89 90 #define HRD(ap) GET_BE_U_2((ap)->ar_hrd) 91 #define HRD_LEN(ap) GET_U_1((ap)->ar_hln) 92 #define PROTO_LEN(ap) GET_U_1((ap)->ar_pln) 93 #define OP(ap) GET_BE_U_2((ap)->ar_op) 94 #define PRO(ap) GET_BE_U_2((ap)->ar_pro) 95 #define SHA(ap) (ar_sha(ap)) 96 #define SPA(ap) (ar_spa(ap)) 97 #define THA(ap) (ar_tha(ap)) 98 #define TPA(ap) (ar_tpa(ap)) 99 100 101 static const struct tok arpop_values[] = { 102 { ARPOP_REQUEST, "Request" }, 103 { ARPOP_REPLY, "Reply" }, 104 { ARPOP_REVREQUEST, "Reverse Request" }, 105 { ARPOP_REVREPLY, "Reverse Reply" }, 106 { ARPOP_INVREQUEST, "Inverse Request" }, 107 { ARPOP_INVREPLY, "Inverse Reply" }, 108 { ARPOP_NAK, "NACK Reply" }, 109 { 0, NULL } 110 }; 111 112 static const struct tok arphrd_values[] = { 113 { ARPHRD_ETHER, "Ethernet" }, 114 { ARPHRD_IEEE802, "TokenRing" }, 115 { ARPHRD_ARCNET, "ArcNet" }, 116 { ARPHRD_FRELAY, "FrameRelay" }, 117 { ARPHRD_STRIP, "Strip" }, 118 { ARPHRD_IEEE1394, "IEEE 1394" }, 119 { ARPHRD_ATM2225, "ATM" }, 120 { ARPHRD_INFINIBAND, "InfiniBand" }, 121 { 0, NULL } 122 }; 123 124 /* 125 * ATM Address Resolution Protocol. 126 * 127 * See RFC 2225 for protocol description. ATMARP packets are similar 128 * to ARP packets, except that there are no length fields for the 129 * protocol address - instead, there are type/length fields for 130 * the ATM number and subaddress - and the hardware addresses consist 131 * of an ATM number and an ATM subaddress. 132 */ 133 struct atmarp_pkthdr { 134 nd_uint16_t aar_hrd; /* format of hardware address */ 135 nd_uint16_t aar_pro; /* format of protocol address */ 136 nd_uint8_t aar_shtl; /* length of source ATM number */ 137 nd_uint8_t aar_sstl; /* length of source ATM subaddress */ 138 #define ATMARP_IS_E164 0x40 /* bit in type/length for E.164 format */ 139 #define ATMARP_LEN_MASK 0x3F /* length of {sub}address in type/length */ 140 nd_uint16_t aar_op; /* same as regular ARP */ 141 nd_uint8_t aar_spln; /* length of source protocol address */ 142 nd_uint8_t aar_thtl; /* length of target ATM number */ 143 nd_uint8_t aar_tstl; /* length of target ATM subaddress */ 144 nd_uint8_t aar_tpln; /* length of target protocol address */ 145 /* 146 * The remaining fields are variable in size, 147 * according to the sizes above. 148 */ 149 #ifdef COMMENT_ONLY 150 nd_byte aar_sha[]; /* source ATM number */ 151 nd_byte aar_ssa[]; /* source ATM subaddress */ 152 nd_byte aar_spa[]; /* sender protocol address */ 153 nd_byte aar_tha[]; /* target ATM number */ 154 nd_byte aar_tsa[]; /* target ATM subaddress */ 155 nd_byte aar_tpa[]; /* target protocol address */ 156 #endif 157 158 #define ATMHRD(ap) GET_BE_U_2((ap)->aar_hrd) 159 #define ATMSHRD_LEN(ap) (GET_U_1((ap)->aar_shtl) & ATMARP_LEN_MASK) 160 #define ATMSSLN(ap) (GET_U_1((ap)->aar_sstl) & ATMARP_LEN_MASK) 161 #define ATMSPROTO_LEN(ap) GET_U_1((ap)->aar_spln) 162 #define ATMOP(ap) GET_BE_U_2((ap)->aar_op) 163 #define ATMPRO(ap) GET_BE_U_2((ap)->aar_pro) 164 #define ATMTHRD_LEN(ap) (GET_U_1((ap)->aar_thtl) & ATMARP_LEN_MASK) 165 #define ATMTSLN(ap) (GET_U_1((ap)->aar_tstl) & ATMARP_LEN_MASK) 166 #define ATMTPROTO_LEN(ap) GET_U_1((ap)->aar_tpln) 167 #define aar_sha(ap) ((const u_char *)((ap)+1)) 168 #define aar_ssa(ap) (aar_sha(ap) + ATMSHRD_LEN(ap)) 169 #define aar_spa(ap) (aar_ssa(ap) + ATMSSLN(ap)) 170 #define aar_tha(ap) (aar_spa(ap) + ATMSPROTO_LEN(ap)) 171 #define aar_tsa(ap) (aar_tha(ap) + ATMTHRD_LEN(ap)) 172 #define aar_tpa(ap) (aar_tsa(ap) + ATMTSLN(ap)) 173 }; 174 175 #define ATMSHA(ap) (aar_sha(ap)) 176 #define ATMSSA(ap) (aar_ssa(ap)) 177 #define ATMSPA(ap) (aar_spa(ap)) 178 #define ATMTHA(ap) (aar_tha(ap)) 179 #define ATMTSA(ap) (aar_tsa(ap)) 180 #define ATMTPA(ap) (aar_tpa(ap)) 181 182 static int 183 isnonzero(netdissect_options *ndo, const u_char *a, size_t len) 184 { 185 while (len > 0) { 186 if (GET_U_1(a) != 0) 187 return (1); 188 a++; 189 len--; 190 } 191 return (0); 192 } 193 194 static void 195 tpaddr_print_ip(netdissect_options *ndo, 196 const struct arp_pkthdr *ap, u_short pro) 197 { 198 if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) 199 ND_PRINT("<wrong proto type>"); 200 else if (PROTO_LEN(ap) != 4) 201 ND_PRINT("<wrong len>"); 202 else 203 ND_PRINT("%s", GET_IPADDR_STRING(TPA(ap))); 204 } 205 206 static void 207 spaddr_print_ip(netdissect_options *ndo, 208 const struct arp_pkthdr *ap, u_short pro) 209 { 210 if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) 211 ND_PRINT("<wrong proto type>"); 212 else if (PROTO_LEN(ap) != 4) 213 ND_PRINT("<wrong len>"); 214 else 215 ND_PRINT("%s", GET_IPADDR_STRING(SPA(ap))); 216 } 217 218 static void 219 atmarp_addr_print(netdissect_options *ndo, 220 const u_char *ha, u_int ha_len, const u_char *srca, 221 u_int srca_len) 222 { 223 if (ha_len == 0) 224 ND_PRINT("<No address>"); 225 else { 226 ND_PRINT("%s", GET_LINKADDR_STRING(ha, LINKADDR_ATM, ha_len)); 227 if (srca_len != 0) 228 ND_PRINT(",%s", 229 GET_LINKADDR_STRING(srca, LINKADDR_ATM, srca_len)); 230 } 231 } 232 233 static void 234 atmarp_tpaddr_print(netdissect_options *ndo, 235 const struct atmarp_pkthdr *ap, u_short pro) 236 { 237 if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) 238 ND_PRINT("<wrong proto type>"); 239 else if (ATMTPROTO_LEN(ap) != 4) 240 ND_PRINT("<wrong tplen>"); 241 else 242 ND_PRINT("%s", GET_IPADDR_STRING(ATMTPA(ap))); 243 } 244 245 static void 246 atmarp_spaddr_print(netdissect_options *ndo, 247 const struct atmarp_pkthdr *ap, u_short pro) 248 { 249 if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) 250 ND_PRINT("<wrong proto type>"); 251 else if (ATMSPROTO_LEN(ap) != 4) 252 ND_PRINT("<wrong splen>"); 253 else 254 ND_PRINT("%s", GET_IPADDR_STRING(ATMSPA(ap))); 255 } 256 257 static void 258 atmarp_print(netdissect_options *ndo, 259 const u_char *bp, u_int length, u_int caplen) 260 { 261 const struct atmarp_pkthdr *ap; 262 u_short pro, hrd, op; 263 264 ap = (const struct atmarp_pkthdr *)bp; 265 ND_TCHECK_SIZE(ap); 266 267 hrd = ATMHRD(ap); 268 pro = ATMPRO(ap); 269 op = ATMOP(ap); 270 271 ND_TCHECK_LEN(ATMTPA(ap), ATMTPROTO_LEN(ap)); 272 273 if (!ndo->ndo_eflag) { 274 ND_PRINT("ARP, "); 275 } 276 277 if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) || 278 ATMSPROTO_LEN(ap) != 4 || 279 ATMTPROTO_LEN(ap) != 4 || 280 ndo->ndo_vflag) { 281 ND_PRINT("%s, %s (len %u/%u)", 282 tok2str(arphrd_values, "Unknown Hardware (%u)", hrd), 283 tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro), 284 ATMSPROTO_LEN(ap), 285 ATMTPROTO_LEN(ap)); 286 287 /* don't know about the address formats */ 288 if (!ndo->ndo_vflag) { 289 goto out; 290 } 291 } 292 293 /* print operation */ 294 ND_PRINT("%s%s ", 295 ndo->ndo_vflag ? ", " : "", 296 tok2str(arpop_values, "Unknown (%u)", op)); 297 298 switch (op) { 299 300 case ARPOP_REQUEST: 301 ND_PRINT("who-has "); 302 atmarp_tpaddr_print(ndo, ap, pro); 303 if (ATMTHRD_LEN(ap) != 0) { 304 ND_PRINT(" ("); 305 atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap), 306 ATMTSA(ap), ATMTSLN(ap)); 307 ND_PRINT(")"); 308 } 309 ND_PRINT(" tell "); 310 atmarp_spaddr_print(ndo, ap, pro); 311 break; 312 313 case ARPOP_REPLY: 314 atmarp_spaddr_print(ndo, ap, pro); 315 ND_PRINT(" is-at "); 316 atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap), 317 ATMSSLN(ap)); 318 break; 319 320 case ARPOP_INVREQUEST: 321 ND_PRINT("who-is "); 322 atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap), ATMTSA(ap), 323 ATMTSLN(ap)); 324 ND_PRINT(" tell "); 325 atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap), 326 ATMSSLN(ap)); 327 break; 328 329 case ARPOP_INVREPLY: 330 atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap), 331 ATMSSLN(ap)); 332 ND_PRINT("at "); 333 atmarp_spaddr_print(ndo, ap, pro); 334 break; 335 336 case ARPOP_NAK: 337 ND_PRINT("for "); 338 atmarp_spaddr_print(ndo, ap, pro); 339 break; 340 341 default: 342 ND_DEFAULTPRINT((const u_char *)ap, caplen); 343 return; 344 } 345 346 out: 347 ND_PRINT(", length %u", length); 348 } 349 350 void 351 arp_print(netdissect_options *ndo, 352 const u_char *bp, u_int length, u_int caplen) 353 { 354 const struct arp_pkthdr *ap; 355 u_short pro, hrd, op, linkaddr; 356 357 ndo->ndo_protocol = "arp"; 358 ap = (const struct arp_pkthdr *)bp; 359 ND_TCHECK_SIZE(ap); 360 361 hrd = HRD(ap); 362 pro = PRO(ap); 363 op = OP(ap); 364 365 366 /* if its ATM then call the ATM ARP printer 367 for Frame-relay ARP most of the fields 368 are similar to Ethernet so overload the Ethernet Printer 369 and set the linkaddr type for GET_LINKADDR_STRING() accordingly */ 370 371 switch(hrd) { 372 case ARPHRD_ATM2225: 373 atmarp_print(ndo, bp, length, caplen); 374 return; 375 case ARPHRD_FRELAY: 376 linkaddr = LINKADDR_FRELAY; 377 break; 378 default: 379 linkaddr = LINKADDR_ETHER; 380 break; 381 } 382 383 ND_TCHECK_LEN(TPA(ap), PROTO_LEN(ap)); 384 385 if (!ndo->ndo_eflag) { 386 ND_PRINT("ARP, "); 387 } 388 389 /* print hardware type/len and proto type/len */ 390 if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) || 391 PROTO_LEN(ap) != 4 || 392 HRD_LEN(ap) == 0 || 393 ndo->ndo_vflag) { 394 ND_PRINT("%s (len %u), %s (len %u)", 395 tok2str(arphrd_values, "Unknown Hardware (%u)", hrd), 396 HRD_LEN(ap), 397 tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro), 398 PROTO_LEN(ap)); 399 400 /* don't know about the address formats */ 401 if (!ndo->ndo_vflag) { 402 goto out; 403 } 404 } 405 406 /* print operation */ 407 ND_PRINT("%s%s ", 408 ndo->ndo_vflag ? ", " : "", 409 tok2str(arpop_values, "Unknown (%u)", op)); 410 411 switch (op) { 412 413 case ARPOP_REQUEST: 414 ND_PRINT("who-has "); 415 tpaddr_print_ip(ndo, ap, pro); 416 if (isnonzero(ndo, (const u_char *)THA(ap), HRD_LEN(ap))) 417 ND_PRINT(" (%s)", 418 GET_LINKADDR_STRING(THA(ap), linkaddr, HRD_LEN(ap))); 419 ND_PRINT(" tell "); 420 spaddr_print_ip(ndo, ap, pro); 421 break; 422 423 case ARPOP_REPLY: 424 spaddr_print_ip(ndo, ap, pro); 425 ND_PRINT(" is-at %s", 426 GET_LINKADDR_STRING(SHA(ap), linkaddr, HRD_LEN(ap))); 427 break; 428 429 case ARPOP_REVREQUEST: 430 /* 431 * XXX - GET_LINKADDR_STRING() may return a pointer to 432 * a static buffer, so we only have one call to it per 433 * ND_PRINT() call. 434 * 435 * This should be done in a cleaner fashion. 436 */ 437 ND_PRINT("who-is %s", 438 GET_LINKADDR_STRING(THA(ap), linkaddr, HRD_LEN(ap))); 439 ND_PRINT(" tell %s", 440 GET_LINKADDR_STRING(SHA(ap), linkaddr, HRD_LEN(ap))); 441 break; 442 443 case ARPOP_REVREPLY: 444 ND_PRINT("%s at ", 445 GET_LINKADDR_STRING(THA(ap), linkaddr, HRD_LEN(ap))); 446 tpaddr_print_ip(ndo, ap, pro); 447 break; 448 449 case ARPOP_INVREQUEST: 450 /* 451 * XXX - GET_LINKADDR_STRING() may return a pointer to 452 * a static buffer, so we only have one call to it per 453 * ND_PRINT() call. 454 * 455 * This should be done in a cleaner fashion. 456 */ 457 ND_PRINT("who-is %s", 458 GET_LINKADDR_STRING(THA(ap), linkaddr, HRD_LEN(ap))); 459 ND_PRINT(" tell %s", 460 GET_LINKADDR_STRING(SHA(ap), linkaddr, HRD_LEN(ap))); 461 break; 462 463 case ARPOP_INVREPLY: 464 ND_PRINT("%s at ", 465 GET_LINKADDR_STRING(SHA(ap), linkaddr, HRD_LEN(ap))); 466 spaddr_print_ip(ndo, ap, pro); 467 break; 468 469 default: 470 ND_DEFAULTPRINT((const u_char *)ap, caplen); 471 return; 472 } 473 474 out: 475 ND_PRINT(", length %u", length); 476 } 477
Indexes created Sat Jun 20 00:25:23 UTC 2026