contrib/tcpdump/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 /* \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 }