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 #include "netdissect.h" 33 #include "addrtoname.h" 34 #include "ether.h" 35 #include "ethertype.h" 36 #include "extract.h" 37 38 static const char tstr[] = "[|ARP]"; 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 u_short 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 u_short ar_pro; /* format of protocol address */ 60 u_char ar_hln; /* length of hardware address */ 61 u_char ar_pln; /* length of protocol address */ 62 u_short 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 u_char ar_sha[]; /* sender hardware address */ 77 u_char ar_spa[]; /* sender protocol address */ 78 u_char ar_tha[]; /* target hardware address */ 79 u_char 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))+ (ap)->ar_hln) 83 #define ar_tha(ap) (((const u_char *)((ap)+1))+ (ap)->ar_hln+(ap)->ar_pln) 84 #define ar_tpa(ap) (((const u_char *)((ap)+1))+2*(ap)->ar_hln+(ap)->ar_pln) 85 }; 86 87 #define ARP_HDRLEN 8 88 89 #define HRD(ap) EXTRACT_16BITS(&(ap)->ar_hrd) 90 #define HRD_LEN(ap) ((ap)->ar_hln) 91 #define PROTO_LEN(ap) ((ap)->ar_pln) 92 #define OP(ap) EXTRACT_16BITS(&(ap)->ar_op) 93 #define PRO(ap) EXTRACT_16BITS(&(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 { 0, NULL } 120 }; 121 122 /* 123 * ATM Address Resolution Protocol. 124 * 125 * See RFC 2225 for protocol description. ATMARP packets are similar 126 * to ARP packets, except that there are no length fields for the 127 * protocol address - instead, there are type/length fields for 128 * the ATM number and subaddress - and the hardware addresses consist 129 * of an ATM number and an ATM subaddress. 130 */ 131 struct atmarp_pkthdr { 132 u_short aar_hrd; /* format of hardware address */ 133 u_short aar_pro; /* format of protocol address */ 134 u_char aar_shtl; /* length of source ATM number */ 135 u_char aar_sstl; /* length of source ATM subaddress */ 136 #define ATMARP_IS_E164 0x40 /* bit in type/length for E.164 format */ 137 #define ATMARP_LEN_MASK 0x3F /* length of {sub}address in type/length */ 138 u_short aar_op; /* same as regular ARP */ 139 u_char aar_spln; /* length of source protocol address */ 140 u_char aar_thtl; /* length of target ATM number */ 141 u_char aar_tstl; /* length of target ATM subaddress */ 142 u_char aar_tpln; /* length of target protocol address */ 143 /* 144 * The remaining fields are variable in size, 145 * according to the sizes above. 146 */ 147 #ifdef COMMENT_ONLY 148 u_char aar_sha[]; /* source ATM number */ 149 u_char aar_ssa[]; /* source ATM subaddress */ 150 u_char aar_spa[]; /* sender protocol address */ 151 u_char aar_tha[]; /* target ATM number */ 152 u_char aar_tsa[]; /* target ATM subaddress */ 153 u_char aar_tpa[]; /* target protocol address */ 154 #endif 155 156 #define ATMHRD(ap) EXTRACT_16BITS(&(ap)->aar_hrd) 157 #define ATMSHRD_LEN(ap) ((ap)->aar_shtl & ATMARP_LEN_MASK) 158 #define ATMSSLN(ap) ((ap)->aar_sstl & ATMARP_LEN_MASK) 159 #define ATMSPROTO_LEN(ap) ((ap)->aar_spln) 160 #define ATMOP(ap) EXTRACT_16BITS(&(ap)->aar_op) 161 #define ATMPRO(ap) EXTRACT_16BITS(&(ap)->aar_pro) 162 #define ATMTHRD_LEN(ap) ((ap)->aar_thtl & ATMARP_LEN_MASK) 163 #define ATMTSLN(ap) ((ap)->aar_tstl & ATMARP_LEN_MASK) 164 #define ATMTPROTO_LEN(ap) ((ap)->aar_tpln) 165 #define aar_sha(ap) ((const u_char *)((ap)+1)) 166 #define aar_ssa(ap) (aar_sha(ap) + ATMSHRD_LEN(ap)) 167 #define aar_spa(ap) (aar_ssa(ap) + ATMSSLN(ap)) 168 #define aar_tha(ap) (aar_spa(ap) + ATMSPROTO_LEN(ap)) 169 #define aar_tsa(ap) (aar_tha(ap) + ATMTHRD_LEN(ap)) 170 #define aar_tpa(ap) (aar_tsa(ap) + ATMTSLN(ap)) 171 }; 172 173 #define ATMSHA(ap) (aar_sha(ap)) 174 #define ATMSSA(ap) (aar_ssa(ap)) 175 #define ATMSPA(ap) (aar_spa(ap)) 176 #define ATMTHA(ap) (aar_tha(ap)) 177 #define ATMTSA(ap) (aar_tsa(ap)) 178 #define ATMTPA(ap) (aar_tpa(ap)) 179 180 static int 181 isnonzero(const u_char *a, size_t len) 182 { 183 while (len > 0) { 184 if (*a != 0) 185 return (1); 186 a++; 187 len--; 188 } 189 return (0); 190 } 191 192 static void 193 atmarp_addr_print(netdissect_options *ndo, 194 const u_char *ha, u_int ha_len, const u_char *srca, 195 u_int srca_len) 196 { 197 if (ha_len == 0) 198 ND_PRINT((ndo, "<No address>")); 199 else { 200 ND_PRINT((ndo, "%s", linkaddr_string(ndo, ha, LINKADDR_ATM, ha_len))); 201 if (srca_len != 0) 202 ND_PRINT((ndo, ",%s", 203 linkaddr_string(ndo, srca, LINKADDR_ATM, srca_len))); 204 } 205 } 206 207 static void 208 atmarp_print(netdissect_options *ndo, 209 const u_char *bp, u_int length, u_int caplen) 210 { 211 const struct atmarp_pkthdr *ap; 212 u_short pro, hrd, op; 213 214 ap = (const struct atmarp_pkthdr *)bp; 215 ND_TCHECK(*ap); 216 217 hrd = ATMHRD(ap); 218 pro = ATMPRO(ap); 219 op = ATMOP(ap); 220 221 if (!ND_TTEST2(*aar_tpa(ap), ATMTPROTO_LEN(ap))) { 222 ND_PRINT((ndo, "%s", tstr)); 223 ND_DEFAULTPRINT((const u_char *)ap, length); 224 return; 225 } 226 227 if (!ndo->ndo_eflag) { 228 ND_PRINT((ndo, "ARP, ")); 229 } 230 231 if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) || 232 ATMSPROTO_LEN(ap) != 4 || 233 ATMTPROTO_LEN(ap) != 4 || 234 ndo->ndo_vflag) { 235 ND_PRINT((ndo, "%s, %s (len %u/%u)", 236 tok2str(arphrd_values, "Unknown Hardware (%u)", hrd), 237 tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro), 238 ATMSPROTO_LEN(ap), 239 ATMTPROTO_LEN(ap))); 240 241 /* don't know know about the address formats */ 242 if (!ndo->ndo_vflag) { 243 goto out; 244 } 245 } 246 247 /* print operation */ 248 ND_PRINT((ndo, "%s%s ", 249 ndo->ndo_vflag ? ", " : "", 250 tok2str(arpop_values, "Unknown (%u)", op))); 251 252 switch (op) { 253 254 case ARPOP_REQUEST: 255 ND_PRINT((ndo, "who-has %s", ipaddr_string(ndo, ATMTPA(ap)))); 256 if (ATMTHRD_LEN(ap) != 0) { 257 ND_PRINT((ndo, " (")); 258 atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap), 259 ATMTSA(ap), ATMTSLN(ap)); 260 ND_PRINT((ndo, ")")); 261 } 262 ND_PRINT((ndo, "tell %s", ipaddr_string(ndo, ATMSPA(ap)))); 263 break; 264 265 case ARPOP_REPLY: 266 ND_PRINT((ndo, "%s is-at ", ipaddr_string(ndo, ATMSPA(ap)))); 267 atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap), 268 ATMSSLN(ap)); 269 break; 270 271 case ARPOP_INVREQUEST: 272 ND_PRINT((ndo, "who-is ")); 273 atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap), ATMTSA(ap), 274 ATMTSLN(ap)); 275 ND_PRINT((ndo, " tell ")); 276 atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap), 277 ATMSSLN(ap)); 278 break; 279 280 case ARPOP_INVREPLY: 281 atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap), 282 ATMSSLN(ap)); 283 ND_PRINT((ndo, "at %s", ipaddr_string(ndo, ATMSPA(ap)))); 284 break; 285 286 case ARPOP_NAK: 287 ND_PRINT((ndo, "for %s", ipaddr_string(ndo, ATMSPA(ap)))); 288 break; 289 290 default: 291 ND_DEFAULTPRINT((const u_char *)ap, caplen); 292 return; 293 } 294 295 out: 296 ND_PRINT((ndo, ", length %u", length)); 297 return; 298 299 trunc: 300 ND_PRINT((ndo, "%s", tstr)); 301 } 302 303 void 304 arp_print(netdissect_options *ndo, 305 const u_char *bp, u_int length, u_int caplen) 306 { 307 const struct arp_pkthdr *ap; 308 u_short pro, hrd, op, linkaddr; 309 310 ap = (const struct arp_pkthdr *)bp; 311 ND_TCHECK(*ap); 312 313 hrd = HRD(ap); 314 pro = PRO(ap); 315 op = OP(ap); 316 317 318 /* if its ATM then call the ATM ARP printer 319 for Frame-relay ARP most of the fields 320 are similar to Ethernet so overload the Ethernet Printer 321 and set the linkaddr type for linkaddr_string(ndo, ) accordingly */ 322 323 switch(hrd) { 324 case ARPHRD_ATM2225: 325 atmarp_print(ndo, bp, length, caplen); 326 return; 327 case ARPHRD_FRELAY: 328 linkaddr = LINKADDR_FRELAY; 329 break; 330 default: 331 linkaddr = LINKADDR_ETHER; 332 break; 333 } 334 335 if (!ND_TTEST2(*ar_tpa(ap), PROTO_LEN(ap))) { 336 ND_PRINT((ndo, "%s", tstr)); 337 ND_DEFAULTPRINT((const u_char *)ap, length); 338 return; 339 } 340 341 if (!ndo->ndo_eflag) { 342 ND_PRINT((ndo, "ARP, ")); 343 } 344 345 /* print hardware type/len and proto type/len */ 346 if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) || 347 PROTO_LEN(ap) != 4 || 348 HRD_LEN(ap) == 0 || 349 ndo->ndo_vflag) { 350 ND_PRINT((ndo, "%s (len %u), %s (len %u)", 351 tok2str(arphrd_values, "Unknown Hardware (%u)", hrd), 352 HRD_LEN(ap), 353 tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro), 354 PROTO_LEN(ap))); 355 356 /* don't know know about the address formats */ 357 if (!ndo->ndo_vflag) { 358 goto out; 359 } 360 } 361 362 /* print operation */ 363 ND_PRINT((ndo, "%s%s ", 364 ndo->ndo_vflag ? ", " : "", 365 tok2str(arpop_values, "Unknown (%u)", op))); 366 367 switch (op) { 368 369 case ARPOP_REQUEST: 370 ND_PRINT((ndo, "who-has %s", ipaddr_string(ndo, TPA(ap)))); 371 if (isnonzero((const u_char *)THA(ap), HRD_LEN(ap))) 372 ND_PRINT((ndo, " (%s)", 373 linkaddr_string(ndo, THA(ap), linkaddr, HRD_LEN(ap)))); 374 ND_PRINT((ndo, " tell %s", ipaddr_string(ndo, SPA(ap)))); 375 break; 376 377 case ARPOP_REPLY: 378 ND_PRINT((ndo, "%s is-at %s", 379 ipaddr_string(ndo, SPA(ap)), 380 linkaddr_string(ndo, SHA(ap), linkaddr, HRD_LEN(ap)))); 381 break; 382 383 case ARPOP_REVREQUEST: 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_REVREPLY: 390 ND_PRINT((ndo, "%s at %s", 391 linkaddr_string(ndo, THA(ap), linkaddr, HRD_LEN(ap)), 392 ipaddr_string(ndo, TPA(ap)))); 393 break; 394 395 case ARPOP_INVREQUEST: 396 ND_PRINT((ndo, "who-is %s tell %s", 397 linkaddr_string(ndo, THA(ap), linkaddr, HRD_LEN(ap)), 398 linkaddr_string(ndo, SHA(ap), linkaddr, HRD_LEN(ap)))); 399 break; 400 401 case ARPOP_INVREPLY: 402 ND_PRINT((ndo,"%s at %s", 403 linkaddr_string(ndo, SHA(ap), linkaddr, HRD_LEN(ap)), 404 ipaddr_string(ndo, SPA(ap)))); 405 break; 406 407 default: 408 ND_DEFAULTPRINT((const u_char *)ap, caplen); 409 return; 410 } 411 412 out: 413 ND_PRINT((ndo, ", length %u", length)); 414 415 return; 416 trunc: 417 ND_PRINT((ndo, "%s", tstr)); 418 } 419 420 /* 421 * Local Variables: 422 * c-style: bsd 423 * End: 424 */ 425 426