The Tcpdump Group git mirrors - tcpdump/blob - print-cdp.c

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