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