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 #define NETDISSECT_REWORKED
  28 #ifdef HAVE_CONFIG_H
  29 #include "config.h"
  30 #endif
  31
  32 #include <tcpdump-stdinc.h>
  33
  34 #include <string.h>
  35
  36 #include "interface.h"
  37 #include "addrtoname.h"
  38 #include "extract.h"                    /* must come after interface.h */
  39 #include "nlpid.h"
  40
  41 static const char tstr[] = "[|cdp]";
  42
  43 #define CDP_HEADER_LEN     4
  44 #define CDP_HEADER_OFFSET  2
  45
  46 static const struct tok cdp_tlv_values[] = {
  47     { 0x01,             "Device-ID"},
  48     { 0x02,             "Address"},
  49     { 0x03,             "Port-ID"},
  50     { 0x04,             "Capability"},
  51     { 0x05,             "Version String"},
  52     { 0x06,             "Platform"},
  53     { 0x07,             "Prefixes"},
  54     { 0x08,             "Protocol-Hello option"},
  55     { 0x09,             "VTP Management Domain"},
  56     { 0x0a,             "Native VLAN ID"},
  57     { 0x0b,             "Duplex"},
  58     { 0x0e,             "ATA-186 VoIP VLAN request"},
  59     { 0x0f,             "ATA-186 VoIP VLAN assignment"},
  60     { 0x10,             "power consumption"},
  61     { 0x11,             "MTU"},
  62     { 0x12,             "AVVID trust bitmap"},
  63     { 0x13,             "AVVID untrusted ports CoS"},
  64     { 0x14,             "System Name"},
  65     { 0x15,             "System Object ID (not decoded)"},
  66     { 0x16,             "Management Addresses"},
  67     { 0x17,             "Physical Location"},
  68     { 0, NULL}
  69 };
  70
  71 static const struct tok cdp_capability_values[] = {
  72     { 0x01,             "Router" },
  73     { 0x02,             "Transparent Bridge" },
  74     { 0x04,             "Source Route Bridge" },
  75     { 0x08,             "L2 Switch" },
  76     { 0x10,             "L3 capable" },
  77     { 0x20,             "IGMP snooping" },
  78     { 0x40,             "L1 capable" },
  79     { 0, NULL }
  80 };
  81
  82 static int cdp_print_addr(netdissect_options *, const u_char *, int);
  83 static int cdp_print_prefixes(netdissect_options *, const u_char *, int);
  84 static unsigned long cdp_get_number(const u_char *, int);
  85
  86 void
  87 cdp_print(netdissect_options *ndo,
  88           const u_char *pptr, u_int length, u_int caplen)
  89 {
  90         int type, len, i, j;
  91         const u_char *tptr;
  92
  93         if (caplen < CDP_HEADER_LEN) {
  94                 ND_PRINT((ndo, "%s", tstr));
  95                 return;
  96         }
  97
  98         tptr = pptr; /* temporary pointer */
  99
 100         ND_TCHECK2(*tptr, CDP_HEADER_LEN);
 101         ND_PRINT((ndo, "CDPv%u, ttl: %us", *tptr, *(tptr + 1)));
 102         if (ndo->ndo_vflag)
 103                 ND_PRINT((ndo, ", checksum: 0x%04x (unverified), length %u", EXTRACT_16BITS(tptr+CDP_HEADER_OFFSET), length));
 104         tptr += CDP_HEADER_LEN;
 105
 106         while (tptr < (pptr+length)) {
 107                 ND_TCHECK2(*tptr, CDP_HEADER_LEN); /* read out Type and Length */
 108                 type = EXTRACT_16BITS(tptr);
 109                 len  = EXTRACT_16BITS(tptr+CDP_HEADER_OFFSET); /* object length includes the 4 bytes header length */
 110                 if (len < CDP_HEADER_LEN) {
 111                     if (ndo->ndo_vflag)
 112                         ND_PRINT((ndo, "\n\t%s (0x%02x), TLV length: %u byte%s (too short)",
 113                                tok2str(cdp_tlv_values,"unknown field type", type),
 114                                type,
 115                                len,
 116                                PLURAL_SUFFIX(len))); /* plural */
 117                     else
 118                         ND_PRINT((ndo, ", %s TLV length %u too short",
 119                                tok2str(cdp_tlv_values,"unknown field type", type),
 120                                len));
 121                     break;
 122                 }
 123                 tptr += CDP_HEADER_LEN;
 124                 len -= CDP_HEADER_LEN;
 125
 126                 ND_TCHECK2(*tptr, len);
 127
 128                 if (ndo->ndo_vflag || type == 1) { /* in non-verbose mode just print Device-ID */
 129
 130                     if (ndo->ndo_vflag)
 131                         ND_PRINT((ndo, "\n\t%s (0x%02x), value length: %u byte%s: ",
 132                                tok2str(cdp_tlv_values,"unknown field type", type),
 133                                type,
 134                                len,
 135                                PLURAL_SUFFIX(len))); /* plural */
 136
 137                     switch (type) {
 138
 139                     case 0x01: /* Device-ID */
 140                         if (!ndo->ndo_vflag)
 141                             ND_PRINT((ndo, ", Device-ID "));
 142                         ND_PRINT((ndo, "'"));
 143                         fn_printn(ndo, tptr, len, NULL);
 144                         ND_PRINT((ndo, "'"));
 145                         break;
 146                     case 0x02: /* Address */
 147                         if (cdp_print_addr(ndo, tptr, len) < 0)
 148                             goto trunc;
 149                         break;
 150                     case 0x03: /* Port-ID */
 151                         ND_PRINT((ndo, "'"));
 152                         fn_printn(ndo, tptr, len, NULL);
 153                         ND_PRINT((ndo, "'"));
 154                         break;
 155                     case 0x04: /* Capabilities */
 156                         ND_PRINT((ndo, "(0x%08x): %s",
 157                                EXTRACT_32BITS(tptr),
 158                                bittok2str(cdp_capability_values, "none", EXTRACT_32BITS(tptr))));
 159                         break;
 160                     case 0x05: /* Version */
 161                         ND_PRINT((ndo, "\n\t  "));
 162                         for (i=0;i<len;i++) {
 163                             j = *(tptr+i);
 164                             ND_PRINT((ndo, "%c", j));
 165                             if (j == 0x0a) /* lets rework the version string to get a nice identation */
 166                                 ND_PRINT((ndo, "\t  "));
 167                         }
 168                         break;
 169                     case 0x06: /* Platform */
 170                         ND_PRINT((ndo, "'"));
 171                         fn_printn(ndo, tptr, len, NULL);
 172                         ND_PRINT((ndo, "'"));
 173                         break;
 174                     case 0x07: /* Prefixes */
 175                         if (cdp_print_prefixes(ndo, tptr, len) < 0)
 176                             goto trunc;
 177                         break;
 178                     case 0x08: /* Protocol Hello Option - not documented */
 179                         break;
 180                     case 0x09: /* VTP Mgmt Domain  - CDPv2 */
 181                         ND_PRINT((ndo, "'"));
 182                         fn_printn(ndo, tptr, len, NULL);
 183                         ND_PRINT((ndo, "'"));
 184                         break;
 185                     case 0x0a: /* Native VLAN ID - CDPv2 */
 186                         ND_PRINT((ndo, "%d", EXTRACT_16BITS(tptr)));
 187                         break;
 188                     case 0x0b: /* Duplex - CDPv2 */
 189                         ND_PRINT((ndo, "%s", *(tptr) ? "full": "half"));
 190                         break;
 191
 192                     /* http://www.cisco.com/univercd/cc/td/doc/product/voice/ata/atarn/186rn21m.htm
 193                      * plus more details from other sources
 194                      */
 195                     case 0x0e: /* ATA-186 VoIP VLAN request - incomplete doc. */
 196                         ND_PRINT((ndo, "app %d, vlan %d", *(tptr), EXTRACT_16BITS(tptr + 1)));
 197                         break;
 198                     case 0x10: /* ATA-186 VoIP VLAN assignment - incomplete doc. */
 199                         ND_PRINT((ndo, "%1.2fW", cdp_get_number(tptr, len) / 1000.0));
 200                         break;
 201                     case 0x11: /* MTU - not documented */
 202                         ND_PRINT((ndo, "%u bytes", EXTRACT_32BITS(tptr)));
 203                         break;
 204                     case 0x12: /* AVVID trust bitmap - not documented */
 205                         ND_PRINT((ndo, "0x%02x", *(tptr)));
 206                         break;
 207                     case 0x13: /* AVVID untrusted port CoS - not documented */
 208                         ND_PRINT((ndo, "0x%02x", *(tptr)));
 209                         break;
 210                     case 0x14: /* System Name - not documented */
 211                         ND_PRINT((ndo, "'"));
 212                         fn_printn(ndo, tptr, len, NULL);
 213                         ND_PRINT((ndo, "'"));
 214                         break;
 215                     case 0x16: /* System Object ID - not documented */
 216                         if (cdp_print_addr(ndo, tptr, len) < 0)
 217                                 goto trunc;
 218                         break;
 219                     case 0x17: /* Physical Location - not documented */
 220                         ND_PRINT((ndo, "0x%02x", *(tptr)));
 221                         if (len > 1) {
 222                                 ND_PRINT((ndo, "/"));
 223                                 fn_printn(ndo, tptr + 1, len - 1, NULL);
 224                         }
 225                         break;
 226                     default:
 227                         print_unknown_data(ndo, tptr, "\n\t  ", len);
 228                         break;
 229                     }
 230                 }
 231                 tptr = tptr+len;
 232         }
 233         if (ndo->ndo_vflag < 1)
 234             ND_PRINT((ndo, ", length %u", caplen));
 235
 236         return;
 237 trunc:
 238         ND_PRINT((ndo, "%s", tstr));
 239 }
 240
 241 /*
 242  * Protocol type values.
 243  *
 244  * PT_NLPID means that the protocol type field contains an OSI NLPID.
 245  *
 246  * PT_IEEE_802_2 means that the protocol type field contains an IEEE 802.2
 247  * LLC header that specifies that the payload is for that protocol.
 248  */
 249 #define PT_NLPID                1       /* OSI NLPID */
 250 #define PT_IEEE_802_2           2       /* IEEE 802.2 LLC header */
 251
 252 static int
 253 cdp_print_addr(netdissect_options *ndo,
 254                const u_char * p, int l)
 255 {
 256         int pt, pl, al, num;
 257         const u_char *endp = p + l;
 258 #ifdef INET6
 259         static const u_char prot_ipv6[] = {
 260                 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x86, 0xdd
 261         };
 262 #endif
 263
 264         ND_TCHECK2(*p, 2);
 265         num = EXTRACT_32BITS(p);
 266         p += 4;
 267
 268         while (p < endp && num >= 0) {
 269                 ND_TCHECK2(*p, 2);
 270                 if (p + 2 > endp)
 271                         goto trunc;
 272                 pt = p[0];              /* type of "protocol" field */
 273                 pl = p[1];              /* length of "protocol" field */
 274                 p += 2;
 275
 276                 ND_TCHECK2(p[pl], 2);
 277                 if (p + pl + 2 > endp)
 278                         goto trunc;
 279                 al = EXTRACT_16BITS(&p[pl]);    /* address length */
 280
 281                 if (pt == PT_NLPID && pl == 1 && *p == NLPID_IP && al == 4) {
 282                         /*
 283                          * IPv4: protocol type = NLPID, protocol length = 1
 284                          * (1-byte NLPID), protocol = 0xcc (NLPID for IPv4),
 285                          * address length = 4
 286                          */
 287                         p += 3;
 288
 289                         ND_TCHECK2(*p, 4);
 290                         if (p + 4 > endp)
 291                                 goto trunc;
 292                         ND_PRINT((ndo, "IPv4 (%u) %s", num, ipaddr_string(ndo, p)));
 293                         p += 4;
 294                 }
 295 #ifdef INET6
 296                 else if (pt == PT_IEEE_802_2 && pl == 8 &&
 297                     memcmp(p, prot_ipv6, 8) == 0 && al == 16) {
 298                         /*
 299                          * IPv6: protocol type = IEEE 802.2 header,
 300                          * protocol length = 8 (size of LLC+SNAP header),
 301                          * protocol = LLC+SNAP header with the IPv6
 302                          * Ethertype, address length = 16
 303                          */
 304                         p += 10;
 305                         ND_TCHECK2(*p, al);
 306                         if (p + al > endp)
 307                                 goto trunc;
 308
 309                         ND_PRINT((ndo, "IPv6 (%u) %s", num, ip6addr_string(ndo, p)));
 310                         p += al;
 311                 }
 312 #endif
 313                 else {
 314                         /*
 315                          * Generic case: just print raw data
 316                          */
 317                         ND_TCHECK2(*p, pl);
 318                         if (p + pl > endp)
 319                                 goto trunc;
 320                         ND_PRINT((ndo, "pt=0x%02x, pl=%d, pb=", *(p - 2), pl));
 321                         while (pl-- > 0)
 322                                 ND_PRINT((ndo, " %02x", *p++));
 323                         ND_TCHECK2(*p, 2);
 324                         if (p + 2 > endp)
 325                                 goto trunc;
 326                         al = (*p << 8) + *(p + 1);
 327                         ND_PRINT((ndo, ", al=%d, a=", al));
 328                         p += 2;
 329                         ND_TCHECK2(*p, al);
 330                         if (p + al > endp)
 331                                 goto trunc;
 332                         while (al-- > 0)
 333                                 ND_PRINT((ndo, " %02x", *p++));
 334                 }
 335                 num--;
 336                 if (num)
 337                         ND_PRINT((ndo, " "));
 338         }
 339
 340         return 0;
 341
 342 trunc:
 343         return -1;
 344 }
 345
 346
 347 static int
 348 cdp_print_prefixes(netdissect_options *ndo,
 349                    const u_char * p, int l)
 350 {
 351         if (l % 5)
 352                 goto trunc;
 353
 354         ND_PRINT((ndo, " IPv4 Prefixes (%d):", l / 5));
 355
 356         while (l > 0) {
 357                 ND_PRINT((ndo, " %u.%u.%u.%u/%u", p[0], p[1], p[2], p[3], p[4]));
 358                 l -= 5;
 359                 p += 5;
 360         }
 361
 362         return 0;
 363
 364 trunc:
 365         return -1;
 366 }
 367
 368 /* read in a <n>-byte number, MSB first
 369  * (of course this can handle max sizeof(long))
 370  */
 371 static unsigned long cdp_get_number(const u_char * p, int l)
 372 {
 373     unsigned long res=0;
 374     while( l>0 )
 375     {
 376         res = (res<<8) + *p;
 377         p++; l--;
 378     }
 379     return res;
 380 }