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 * $FreeBSD$ 22 */ 23 24 #ifndef lint 25 static const char rcsid[] _U_ = 26 "@(#) $Header: /tcpdump/master/tcpdump/print-arp.c,v 1.61.2.2 2003/11/16 08:51:10 guy Exp $ (LBL)"; 27 #endif 28 29 #ifdef HAVE_CONFIG_H 30 #include "config.h" 31 #endif 32 33 #include <tcpdump-stdinc.h> 34 35 #include <stdio.h> 36 #include <string.h> 37 38 #include "interface.h" 39 #include "addrtoname.h" 40 #include "ether.h" 41 #include "ethertype.h" 42 #include "extract.h" /* must come after interface.h */ 43 44 /* 45 * Address Resolution Protocol. 46 * 47 * See RFC 826 for protocol description. ARP packets are variable 48 * in size; the arphdr structure defines the fixed-length portion. 49 * Protocol type values are the same as those for 10 Mb/s Ethernet. 50 * It is followed by the variable-sized fields ar_sha, arp_spa, 51 * arp_tha and arp_tpa in that order, according to the lengths 52 * specified. Field names used correspond to RFC 826. 53 */ 54 struct arp_pkthdr { 55 u_short ar_hrd; /* format of hardware address */ 56 #define ARPHRD_ETHER 1 /* ethernet hardware format */ 57 #define ARPHRD_IEEE802 6 /* token-ring hardware format */ 58 #define ARPHRD_ARCNET 7 /* arcnet hardware format */ 59 #define ARPHRD_FRELAY 15 /* frame relay hardware format */ 60 #define ARPHRD_STRIP 23 /* Ricochet Starmode Radio hardware format */ 61 #define ARPHRD_IEEE1394 24 /* IEEE 1394 (FireWire) hardware format */ 62 u_short ar_pro; /* format of protocol address */ 63 u_char ar_hln; /* length of hardware address */ 64 u_char ar_pln; /* length of protocol address */ 65 u_short ar_op; /* one of: */ 66 #define ARPOP_REQUEST 1 /* request to resolve address */ 67 #define ARPOP_REPLY 2 /* response to previous request */ 68 #define ARPOP_REVREQUEST 3 /* request protocol address given hardware */ 69 #define ARPOP_REVREPLY 4 /* response giving protocol address */ 70 #define ARPOP_INVREQUEST 8 /* request to identify peer */ 71 #define ARPOP_INVREPLY 9 /* response identifying peer */ 72 /* 73 * The remaining fields are variable in size, 74 * according to the sizes above. 75 */ 76 #ifdef COMMENT_ONLY 77 u_char ar_sha[]; /* sender hardware address */ 78 u_char ar_spa[]; /* sender protocol address */ 79 u_char ar_tha[]; /* target hardware address */ 80 u_char 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))+ (ap)->ar_hln) 84 #define ar_tha(ap) (((const u_char *)((ap)+1))+ (ap)->ar_hln+(ap)->ar_pln) 85 #define ar_tpa(ap) (((const u_char *)((ap)+1))+2*(ap)->ar_hln+(ap)->ar_pln) 86 }; 87 88 #define ARP_HDRLEN 8 89 90 #define HRD(ap) EXTRACT_16BITS(&(ap)->ar_hrd) 91 #define HLN(ap) ((ap)->ar_hln) 92 #define PLN(ap) ((ap)->ar_pln) 93 #define OP(ap) EXTRACT_16BITS(&(ap)->ar_op) 94 #define PRO(ap) EXTRACT_16BITS(&(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 * ATM Address Resolution Protocol. 102 * 103 * See RFC 2225 for protocol description. ATMARP packets are similar 104 * to ARP packets, except that there are no length fields for the 105 * protocol address - instead, there are type/length fields for 106 * the ATM number and subaddress - and the hardware addresses consist 107 * of an ATM number and an ATM subaddress. 108 */ 109 struct atmarp_pkthdr { 110 u_short aar_hrd; /* format of hardware address */ 111 #define ARPHRD_ATM2225 19 /* ATM (RFC 2225) */ 112 u_short aar_pro; /* format of protocol address */ 113 u_char aar_shtl; /* length of source ATM number */ 114 u_char aar_sstl; /* length of source ATM subaddress */ 115 #define ATMARP_IS_E164 0x40 /* bit in type/length for E.164 format */ 116 #define ATMARP_LEN_MASK 0x3F /* length of {sub}address in type/length */ 117 u_short aar_op; /* same as regular ARP */ 118 #define ATMARPOP_NAK 10 /* NAK */ 119 u_char aar_spln; /* length of source protocol address */ 120 u_char aar_thtl; /* length of target ATM number */ 121 u_char aar_tstl; /* length of target ATM subaddress */ 122 u_char aar_tpln; /* length of target protocol address */ 123 /* 124 * The remaining fields are variable in size, 125 * according to the sizes above. 126 */ 127 #ifdef COMMENT_ONLY 128 u_char aar_sha[]; /* source ATM number */ 129 u_char aar_ssa[]; /* source ATM subaddress */ 130 u_char aar_spa[]; /* sender protocol address */ 131 u_char aar_tha[]; /* target ATM number */ 132 u_char aar_tsa[]; /* target ATM subaddress */ 133 u_char aar_tpa[]; /* target protocol address */ 134 #endif 135 136 #define ATMHRD(ap) EXTRACT_16BITS(&(ap)->aar_hrd) 137 #define ATMSHLN(ap) ((ap)->aar_shtl & ATMARP_LEN_MASK) 138 #define ATMSSLN(ap) ((ap)->aar_sstl & ATMARP_LEN_MASK) 139 #define ATMSPLN(ap) ((ap)->aar_spln) 140 #define ATMOP(ap) EXTRACT_16BITS(&(ap)->aar_op) 141 #define ATMPRO(ap) EXTRACT_16BITS(&(ap)->aar_pro) 142 #define ATMTHLN(ap) ((ap)->aar_thtl & ATMARP_LEN_MASK) 143 #define ATMTSLN(ap) ((ap)->aar_tstl & ATMARP_LEN_MASK) 144 #define ATMTPLN(ap) ((ap)->aar_tpln) 145 #define aar_sha(ap) ((const u_char *)((ap)+1)) 146 #define aar_ssa(ap) (aar_sha(ap) + ATMSHLN(ap)) 147 #define aar_spa(ap) (aar_ssa(ap) + ATMSSLN(ap)) 148 #define aar_tha(ap) (aar_spa(ap) + ATMSPLN(ap)) 149 #define aar_tsa(ap) (aar_tha(ap) + ATMTHLN(ap)) 150 #define aar_tpa(ap) (aar_tsa(ap) + ATMTSLN(ap)) 151 }; 152 153 #define ATMSHA(ap) (aar_sha(ap)) 154 #define ATMSSA(ap) (aar_ssa(ap)) 155 #define ATMSPA(ap) (aar_spa(ap)) 156 #define ATMTHA(ap) (aar_tha(ap)) 157 #define ATMTSA(ap) (aar_tsa(ap)) 158 #define ATMTPA(ap) (aar_tpa(ap)) 159 160 static u_char ezero[6]; 161 162 static void 163 atmarp_addr_print(const u_char *ha, u_int ha_len, const u_char *srca, 164 u_int srca_len) 165 { 166 if (ha_len == 0) 167 (void)printf("<No address>"); 168 else { 169 (void)printf("%s", linkaddr_string(ha, ha_len)); 170 if (srca_len != 0) 171 (void)printf(",%s", linkaddr_string(srca, srca_len)); 172 } 173 } 174 175 static void 176 atmarp_print(const u_char *bp, u_int length, u_int caplen) 177 { 178 const struct atmarp_pkthdr *ap; 179 u_short pro, hrd, op; 180 181 ap = (const struct atmarp_pkthdr *)bp; 182 TCHECK(*ap); 183 184 hrd = ATMHRD(ap); 185 pro = ATMPRO(ap); 186 op = ATMOP(ap); 187 188 if (!TTEST2(*aar_tpa(ap), ATMTPLN(ap))) { 189 (void)printf("truncated-atmarp"); 190 default_print((const u_char *)ap, length); 191 return; 192 } 193 194 if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) || 195 ATMSPLN(ap) != 4 || ATMTPLN(ap) != 4) { 196 (void)printf("atmarp-#%d for proto #%d (%d/%d) hardware #%d", 197 op, pro, ATMSPLN(ap), ATMTPLN(ap), hrd); 198 return; 199 } 200 if (pro == ETHERTYPE_TRAIL) 201 (void)printf("trailer-"); 202 switch (op) { 203 204 case ARPOP_REQUEST: 205 (void)printf("arp who-has %s", ipaddr_string(ATMTPA(ap))); 206 if (ATMTHLN(ap) != 0) { 207 (void)printf(" ("); 208 atmarp_addr_print(ATMTHA(ap), ATMTHLN(ap), 209 ATMTSA(ap), ATMTSLN(ap)); 210 (void)printf(")"); 211 } 212 (void)printf(" tell %s", ipaddr_string(ATMSPA(ap))); 213 break; 214 215 case ARPOP_REPLY: 216 (void)printf("arp reply %s", ipaddr_string(ATMSPA(ap))); 217 (void)printf(" is-at "); 218 atmarp_addr_print(ATMSHA(ap), ATMSHLN(ap), ATMSSA(ap), 219 ATMSSLN(ap)); 220 break; 221 222 case ARPOP_INVREQUEST: 223 (void)printf("invarp who-is "); 224 atmarp_addr_print(ATMTHA(ap), ATMTHLN(ap), ATMTSA(ap), 225 ATMTSLN(ap)); 226 (void)printf(" tell "); 227 atmarp_addr_print(ATMSHA(ap), ATMSHLN(ap), ATMSSA(ap), 228 ATMSSLN(ap)); 229 break; 230 231 case ARPOP_INVREPLY: 232 (void)printf("invarp reply "); 233 atmarp_addr_print(ATMSHA(ap), ATMSHLN(ap), ATMSSA(ap), 234 ATMSSLN(ap)); 235 (void)printf(" at %s", ipaddr_string(ATMSPA(ap))); 236 break; 237 238 case ATMARPOP_NAK: 239 (void)printf("nak reply for %s", 240 ipaddr_string(ATMSPA(ap))); 241 break; 242 243 default: 244 (void)printf("atmarp-#%d", op); 245 default_print((const u_char *)ap, caplen); 246 return; 247 } 248 return; 249 trunc: 250 (void)printf("[|atmarp]"); 251 } 252 253 void 254 arp_print(const u_char *bp, u_int length, u_int caplen) 255 { 256 const struct arp_pkthdr *ap; 257 u_short pro, hrd, op; 258 259 ap = (const struct arp_pkthdr *)bp; 260 TCHECK(*ap); 261 hrd = HRD(ap); 262 if (hrd == ARPHRD_ATM2225) { 263 atmarp_print(bp, length, caplen); 264 return; 265 } 266 pro = PRO(ap); 267 op = OP(ap); 268 269 if (!TTEST2(*ar_tpa(ap), PLN(ap))) { 270 (void)printf("truncated-arp"); 271 default_print((const u_char *)ap, length); 272 return; 273 } 274 275 if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) || 276 PLN(ap) != 4 || HLN(ap) == 0) { 277 (void)printf("arp-#%d for proto #%d (%d) hardware #%d (%d)", 278 op, pro, PLN(ap), hrd, HLN(ap)); 279 return; 280 } 281 if (pro == ETHERTYPE_TRAIL) 282 (void)printf("trailer-"); 283 switch (op) { 284 285 case ARPOP_REQUEST: 286 (void)printf("arp who-has %s", ipaddr_string(TPA(ap))); 287 if (memcmp((const char *)ezero, (const char *)THA(ap), HLN(ap)) != 0) 288 (void)printf(" (%s)", 289 linkaddr_string(THA(ap), HLN(ap))); 290 (void)printf(" tell %s", ipaddr_string(SPA(ap))); 291 break; 292 293 case ARPOP_REPLY: 294 (void)printf("arp reply %s", ipaddr_string(SPA(ap))); 295 (void)printf(" is-at %s", linkaddr_string(SHA(ap), HLN(ap))); 296 break; 297 298 case ARPOP_REVREQUEST: 299 (void)printf("rarp who-is %s tell %s", 300 linkaddr_string(THA(ap), HLN(ap)), 301 linkaddr_string(SHA(ap), HLN(ap))); 302 break; 303 304 case ARPOP_REVREPLY: 305 (void)printf("rarp reply %s at %s", 306 linkaddr_string(THA(ap), HLN(ap)), 307 ipaddr_string(TPA(ap))); 308 break; 309 310 case ARPOP_INVREQUEST: 311 (void)printf("invarp who-is %s tell %s", 312 linkaddr_string(THA(ap), HLN(ap)), 313 linkaddr_string(SHA(ap), HLN(ap))); 314 break; 315 316 case ARPOP_INVREPLY: 317 (void)printf("invarp reply %s at %s", 318 linkaddr_string(THA(ap), HLN(ap)), 319 ipaddr_string(TPA(ap))); 320 break; 321 322 default: 323 (void)printf("arp-#%d", op); 324 default_print((const u_char *)ap, caplen); 325 return; 326 } 327 if (hrd != ARPHRD_ETHER) 328 printf(" hardware #%d", hrd); 329 return; 330 trunc: 331 (void)printf("[|arp]"); 332 } 333