1 /* 2 * Copyright (c) 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 * Code by Gert Doering, SpaceNet GmbH, gert (at) space.net 22 * 23 * Reference documentation: 24 * http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/frames.htm 25 */ 26 27 /* \summary: Cisco Discovery Protocol (CDP) printer */ 28 29 #ifdef HAVE_CONFIG_H 30 #include "config.h" 31 #endif 32 33 #include <netdissect-stdinc.h> 34 35 #include <string.h> 36 37 #include "netdissect.h" 38 #include "addrtoname.h" 39 #include "extract.h" 40 #include "nlpid.h" 41 42 static const char tstr[] = "[|cdp]"; 43 44 #define CDP_HEADER_LEN 4 45 #define CDP_HEADER_VERSION_OFFSET 0 46 #define CDP_HEADER_TTL_OFFSET 1 47 #define CDP_HEADER_CHECKSUM_OFFSET 2 48 49 #define CDP_TLV_HEADER_LEN 4 50 #define CDP_TLV_TYPE_OFFSET 0 51 #define CDP_TLV_LEN_OFFSET 2 52 53 static const struct tok cdp_tlv_values[] = { 54 { 0x01, "Device-ID"}, 55 { 0x02, "Address"}, 56 { 0x03, "Port-ID"}, 57 { 0x04, "Capability"}, 58 { 0x05, "Version String"}, 59 { 0x06, "Platform"}, 60 { 0x07, "Prefixes"}, 61 { 0x08, "Protocol-Hello option"}, 62 { 0x09, "VTP Management Domain"}, 63 { 0x0a, "Native VLAN ID"}, 64 { 0x0b, "Duplex"}, 65 { 0x0e, "ATA-186 VoIP VLAN request"}, 66 { 0x0f, "ATA-186 VoIP VLAN assignment"}, 67 { 0x10, "power consumption"}, 68 { 0x11, "MTU"}, 69 { 0x12, "AVVID trust bitmap"}, 70 { 0x13, "AVVID untrusted ports CoS"}, 71 { 0x14, "System Name"}, 72 { 0x15, "System Object ID (not decoded)"}, 73 { 0x16, "Management Addresses"}, 74 { 0x17, "Physical Location"}, 75 { 0, NULL} 76 }; 77 78 static const struct tok cdp_capability_values[] = { 79 { 0x01, "Router" }, 80 { 0x02, "Transparent Bridge" }, 81 { 0x04, "Source Route Bridge" }, 82 { 0x08, "L2 Switch" }, 83 { 0x10, "L3 capable" }, 84 { 0x20, "IGMP snooping" }, 85 { 0x40, "L1 capable" }, 86 { 0, NULL } 87 }; 88 89 static int cdp_print_addr(netdissect_options *, const u_char *, int); 90 static int cdp_print_prefixes(netdissect_options *, const u_char *, int); 91 static unsigned long cdp_get_number(const u_char *, int); 92 93 void 94 cdp_print(netdissect_options *ndo, 95 const u_char *pptr, u_int length, u_int caplen) 96 { 97 int type, len, i, j; 98 const u_char *tptr; 99 100 if (caplen < CDP_HEADER_LEN) { 101 ND_PRINT((ndo, "%s", tstr)); 102 return; 103 } 104 105 tptr = pptr; /* temporary pointer */ 106 107 ND_TCHECK2(*tptr, CDP_HEADER_LEN); 108 ND_PRINT((ndo, "CDPv%u, ttl: %us", *(tptr + CDP_HEADER_VERSION_OFFSET), 109 *(tptr + CDP_HEADER_TTL_OFFSET))); 110 if (ndo->ndo_vflag) 111 ND_PRINT((ndo, ", checksum: 0x%04x (unverified), length %u", EXTRACT_16BITS(tptr+CDP_HEADER_CHECKSUM_OFFSET), length)); 112 tptr += CDP_HEADER_LEN; 113 114 while (tptr < (pptr+length)) { 115 ND_TCHECK2(*tptr, CDP_TLV_HEADER_LEN); /* read out Type and Length */ 116 type = EXTRACT_16BITS(tptr+CDP_TLV_TYPE_OFFSET); 117 len = EXTRACT_16BITS(tptr+CDP_TLV_LEN_OFFSET); /* object length includes the 4 bytes header length */ 118 if (len < CDP_TLV_HEADER_LEN) { 119 if (ndo->ndo_vflag) 120 ND_PRINT((ndo, "\n\t%s (0x%02x), TLV length: %u byte%s (too short)", 121 tok2str(cdp_tlv_values,"unknown field type", type), 122 type, 123 len, 124 PLURAL_SUFFIX(len))); /* plural */ 125 else 126 ND_PRINT((ndo, ", %s TLV length %u too short", 127 tok2str(cdp_tlv_values,"unknown field type", type), 128 len)); 129 break; 130 } 131 tptr += CDP_TLV_HEADER_LEN; 132 len -= CDP_TLV_HEADER_LEN; 133 134 ND_TCHECK2(*tptr, len); 135 136 if (ndo->ndo_vflag || type == 1) { /* in non-verbose mode just print Device-ID */ 137 138 if (ndo->ndo_vflag) 139 ND_PRINT((ndo, "\n\t%s (0x%02x), value length: %u byte%s: ", 140 tok2str(cdp_tlv_values,"unknown field type", type), 141 type, 142 len, 143 PLURAL_SUFFIX(len))); /* plural */ 144 145 switch (type) { 146 147 case 0x01: /* Device-ID */ 148 if (!ndo->ndo_vflag) 149 ND_PRINT((ndo, ", Device-ID ")); 150 ND_PRINT((ndo, "'")); 151 (void)fn_printn(ndo, tptr, len, NULL); 152 ND_PRINT((ndo, "'")); 153 break; 154 case 0x02: /* Address */ 155 if (cdp_print_addr(ndo, tptr, len) < 0) 156 goto trunc; 157 break; 158 case 0x03: /* Port-ID */ 159 ND_PRINT((ndo, "'")); 160 (void)fn_printn(ndo, tptr, len, NULL); 161 ND_PRINT((ndo, "'")); 162 break; 163 case 0x04: /* Capabilities */ 164 if (len < 4) 165 goto trunc; 166 ND_PRINT((ndo, "(0x%08x): %s", 167 EXTRACT_32BITS(tptr), 168 bittok2str(cdp_capability_values, "none", EXTRACT_32BITS(tptr)))); 169 break; 170 case 0x05: /* Version */ 171 ND_PRINT((ndo, "\n\t ")); 172 for (i=0;i<len;i++) { 173 j = *(tptr+i); 174 if (j == '\n') /* lets rework the version string to 175 get a nice indentation */ 176 ND_PRINT((ndo, "\n\t ")); 177 else 178 fn_print_char(ndo, j); 179 } 180 break; 181 case 0x06: /* Platform */ 182 ND_PRINT((ndo, "'")); 183 (void)fn_printn(ndo, tptr, len, NULL); 184 ND_PRINT((ndo, "'")); 185 break; 186 case 0x07: /* Prefixes */ 187 if (cdp_print_prefixes(ndo, tptr, len) < 0) 188 goto trunc; 189 break; 190 case 0x08: /* Protocol Hello Option - not documented */ 191 break; 192 case 0x09: /* VTP Mgmt Domain - CDPv2 */ 193 ND_PRINT((ndo, "'")); 194 (void)fn_printn(ndo, tptr, len, NULL); 195 ND_PRINT((ndo, "'")); 196 break; 197 case 0x0a: /* Native VLAN ID - CDPv2 */ 198 if (len < 2) 199 goto trunc; 200 ND_PRINT((ndo, "%d", EXTRACT_16BITS(tptr))); 201 break; 202 case 0x0b: /* Duplex - CDPv2 */ 203 if (len < 1) 204 goto trunc; 205 ND_PRINT((ndo, "%s", *(tptr) ? "full": "half")); 206 break; 207 208 /* http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cata/186/2_12_m/english/release/notes/186rn21m.html 209 * plus more details from other sources 210 */ 211 case 0x0e: /* ATA-186 VoIP VLAN request - incomplete doc. */ 212 if (len < 3) 213 goto trunc; 214 ND_PRINT((ndo, "app %d, vlan %d", *(tptr), EXTRACT_16BITS(tptr + 1))); 215 break; 216 case 0x10: /* ATA-186 VoIP VLAN assignment - incomplete doc. */ 217 ND_PRINT((ndo, "%1.2fW", cdp_get_number(tptr, len) / 1000.0)); 218 break; 219 case 0x11: /* MTU - not documented */ 220 if (len < 4) 221 goto trunc; 222 ND_PRINT((ndo, "%u bytes", EXTRACT_32BITS(tptr))); 223 break; 224 case 0x12: /* AVVID trust bitmap - not documented */ 225 if (len < 1) 226 goto trunc; 227 ND_PRINT((ndo, "0x%02x", *(tptr))); 228 break; 229 case 0x13: /* AVVID untrusted port CoS - not documented */ 230 if (len < 1) 231 goto trunc; 232 ND_PRINT((ndo, "0x%02x", *(tptr))); 233 break; 234 case 0x14: /* System Name - not documented */ 235 ND_PRINT((ndo, "'")); 236 (void)fn_printn(ndo, tptr, len, NULL); 237 ND_PRINT((ndo, "'")); 238 break; 239 case 0x16: /* System Object ID - not documented */ 240 if (cdp_print_addr(ndo, tptr, len) < 0) 241 goto trunc; 242 break; 243 case 0x17: /* Physical Location - not documented */ 244 if (len < 1) 245 goto trunc; 246 ND_PRINT((ndo, "0x%02x", *(tptr))); 247 if (len > 1) { 248 ND_PRINT((ndo, "/")); 249 (void)fn_printn(ndo, tptr + 1, len - 1, NULL); 250 } 251 break; 252 default: 253 print_unknown_data(ndo, tptr, "\n\t ", len); 254 break; 255 } 256 } 257 tptr = tptr+len; 258 } 259 if (ndo->ndo_vflag < 1) 260 ND_PRINT((ndo, ", length %u", caplen)); 261 262 return; 263 trunc: 264 ND_PRINT((ndo, "%s", tstr)); 265 } 266 267 /* 268 * Protocol type values. 269 * 270 * PT_NLPID means that the protocol type field contains an OSI NLPID. 271 * 272 * PT_IEEE_802_2 means that the protocol type field contains an IEEE 802.2 273 * LLC header that specifies that the payload is for that protocol. 274 */ 275 #define PT_NLPID 1 /* OSI NLPID */ 276 #define PT_IEEE_802_2 2 /* IEEE 802.2 LLC header */ 277 278 static int 279 cdp_print_addr(netdissect_options *ndo, 280 const u_char * p, int l) 281 { 282 int pt, pl, al, num; 283 const u_char *endp = p + l; 284 static const u_char prot_ipv6[] = { 285 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x86, 0xdd 286 }; 287 288 ND_TCHECK2(*p, 4); 289 if (p + 4 > endp) 290 goto trunc; 291 num = EXTRACT_32BITS(p); 292 p += 4; 293 294 while (p < endp && num >= 0) { 295 ND_TCHECK2(*p, 2); 296 if (p + 2 > endp) 297 goto trunc; 298 pt = p[0]; /* type of "protocol" field */ 299 pl = p[1]; /* length of "protocol" field */ 300 p += 2; 301 302 ND_TCHECK2(p[pl], 2); 303 if (p + pl + 2 > endp) 304 goto trunc; 305 al = EXTRACT_16BITS(&p[pl]); /* address length */ 306 307 if (pt == PT_NLPID && pl == 1 && *p == NLPID_IP && al == 4) { 308 /* 309 * IPv4: protocol type = NLPID, protocol length = 1 310 * (1-byte NLPID), protocol = 0xcc (NLPID for IPv4), 311 * address length = 4 312 */ 313 p += 3; 314 315 ND_TCHECK2(*p, 4); 316 if (p + 4 > endp) 317 goto trunc; 318 ND_PRINT((ndo, "IPv4 (%u) %s", num, ipaddr_string(ndo, p))); 319 p += 4; 320 } 321 else if (pt == PT_IEEE_802_2 && pl == 8 && 322 memcmp(p, prot_ipv6, 8) == 0 && al == 16) { 323 /* 324 * IPv6: protocol type = IEEE 802.2 header, 325 * protocol length = 8 (size of LLC+SNAP header), 326 * protocol = LLC+SNAP header with the IPv6 327 * Ethertype, address length = 16 328 */ 329 p += 10; 330 ND_TCHECK2(*p, al); 331 if (p + al > endp) 332 goto trunc; 333 334 ND_PRINT((ndo, "IPv6 (%u) %s", num, ip6addr_string(ndo, p))); 335 p += al; 336 } 337 else { 338 /* 339 * Generic case: just print raw data 340 */ 341 ND_TCHECK2(*p, pl); 342 if (p + pl > endp) 343 goto trunc; 344 ND_PRINT((ndo, "pt=0x%02x, pl=%d, pb=", *(p - 2), pl)); 345 while (pl-- > 0) 346 ND_PRINT((ndo, " %02x", *p++)); 347 ND_TCHECK2(*p, 2); 348 if (p + 2 > endp) 349 goto trunc; 350 al = (*p << 8) + *(p + 1); 351 ND_PRINT((ndo, ", al=%d, a=", al)); 352 p += 2; 353 ND_TCHECK2(*p, al); 354 if (p + al > endp) 355 goto trunc; 356 while (al-- > 0) 357 ND_PRINT((ndo, " %02x", *p++)); 358 } 359 num--; 360 if (num) 361 ND_PRINT((ndo, " ")); 362 } 363 364 return 0; 365 366 trunc: 367 return -1; 368 } 369 370 371 static int 372 cdp_print_prefixes(netdissect_options *ndo, 373 const u_char * p, int l) 374 { 375 if (l % 5) 376 goto trunc; 377 378 ND_PRINT((ndo, " IPv4 Prefixes (%d):", l / 5)); 379 380 while (l > 0) { 381 ND_PRINT((ndo, " %u.%u.%u.%u/%u", p[0], p[1], p[2], p[3], p[4])); 382 l -= 5; 383 p += 5; 384 } 385 386 return 0; 387 388 trunc: 389 return -1; 390 } 391 392 /* read in a <n>-byte number, MSB first 393 * (of course this can handle max sizeof(long)) 394 */ 395 static unsigned long cdp_get_number(const u_char * p, int l) 396 { 397 unsigned long res=0; 398 while( l>0 ) 399 { 400 res = (res<<8) + *p; 401 p++; l--; 402 } 403 return res; 404 } 405
