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         if (!ND_TTEST2(*tptr, CDP_HEADER_LEN))
 100                 goto trunc;
 101         ND_PRINT((ndo, "CDPv%u, ttl: %us", *tptr, *(tptr + 1)));
 102         if (ndo->ndo_vflag)
 103                 ND_PRINT((ndo, ", checksum: %u (unverified), length %u", EXTRACT_16BITS(tptr), length));
 104         tptr += CDP_HEADER_LEN;
 105
 106         while (tptr < (pptr+length)) {
 107
 108                 if (!ND_TTEST2(*tptr, 4)) /* read out Type and Length */
 109                     goto trunc;
 110                 type = EXTRACT_16BITS(tptr);
 111                 len  = EXTRACT_16BITS(tptr+2); /* object length includes the 4 bytes header length */
 112                 tptr += 4;
 113                 len -= 4;
 114
 115                 if (!ND_TTEST2(*tptr, len))
 116                         goto trunc;
 117
 118                 if (ndo->ndo_vflag || type == 1) { /* in non-verbose mode just print Device-ID */
 119
 120                     if (ndo->ndo_vflag)
 121                         ND_PRINT((ndo, "\n\t%s (0x%02x), length: %u byte%s: ",
 122                                tok2str(cdp_tlv_values,"unknown field type", type),
 123                                type,
 124                                len,
 125                                PLURAL_SUFFIX(len))); /* plural */
 126
 127                     switch (type) {
 128
 129                     case 0x01: /* Device-ID */
 130                         if (!ndo->ndo_vflag)
 131                             ND_PRINT((ndo, ", Device-ID "));
 132                         ND_PRINT((ndo, "'"));
 133                         fn_printn(tptr, len, NULL);
 134                         ND_PRINT((ndo, "'"));
 135                         break;
 136                     case 0x02: /* Address */
 137                         if (cdp_print_addr(ndo, tptr, len) < 0)
 138                             goto trunc;
 139                         break;
 140                     case 0x03: /* Port-ID */
 141                         ND_PRINT((ndo, "'"));
 142                         fn_printn(tptr, len, NULL);
 143                         ND_PRINT((ndo, "'"));
 144                         break;
 145                     case 0x04: /* Capabilities */
 146                         ND_PRINT((ndo, "(0x%08x): %s",
 147                                EXTRACT_32BITS(tptr),
 148                                bittok2str(cdp_capability_values, "none", EXTRACT_32BITS(tptr))));
 149                         break;
 150                     case 0x05: /* Version */
 151                         ND_PRINT((ndo, "\n\t  "));
 152                         for (i=0;i<len;i++) {
 153                             j = *(tptr+i);
 154                             ND_PRINT((ndo, "%c", j));
 155                             if (j == 0x0a) /* lets rework the version string to get a nice identation */
 156                                 ND_PRINT((ndo, "\t  "));
 157                         }
 158                         break;
 159                     case 0x06: /* Platform */
 160                         ND_PRINT((ndo, "'"));
 161                         fn_printn(tptr, len, NULL);
 162                         ND_PRINT((ndo, "'"));
 163                         break;
 164                     case 0x07: /* Prefixes */
 165                         if (cdp_print_prefixes(ndo, tptr, len) < 0)
 166                             goto trunc;
 167                         break;
 168                     case 0x08: /* Protocol Hello Option - not documented */
 169                         break;
 170                     case 0x09: /* VTP Mgmt Domain  - not documented */
 171                         ND_PRINT((ndo, "'"));
 172                         fn_printn(tptr, len, NULL);
 173                         ND_PRINT((ndo, "'"));
 174                         break;
 175                     case 0x0a: /* Native VLAN ID - not documented */
 176                         ND_PRINT((ndo, "%d", EXTRACT_16BITS(tptr)));
 177                         break;
 178                     case 0x0b: /* Duplex - not documented */
 179                         ND_PRINT((ndo, "%s", *(tptr) ? "full": "half"));
 180                         break;
 181
 182                     /* http://www.cisco.com/univercd/cc/td/doc/product/voice/ata/atarn/186rn21m.htm
 183                      * plus more details from other sources
 184                      */
 185                     case 0x0e: /* ATA-186 VoIP VLAN request - incomplete doc. */
 186                         ND_PRINT((ndo, "app %d, vlan %d", *(tptr), EXTRACT_16BITS(tptr + 1)));
 187                         break;
 188                     case 0x10: /* ATA-186 VoIP VLAN assignment - incomplete doc. */
 189                         ND_PRINT((ndo, "%1.2fW", cdp_get_number(tptr, len) / 1000.0));
 190                         break;
 191                     case 0x11: /* MTU - not documented */
 192                         ND_PRINT((ndo, "%u bytes", EXTRACT_32BITS(tptr)));
 193                         break;
 194                     case 0x12: /* AVVID trust bitmap - not documented */
 195                         ND_PRINT((ndo, "0x%02x", *(tptr)));
 196                         break;
 197                     case 0x13: /* AVVID untrusted port CoS - not documented */
 198                         ND_PRINT((ndo, "0x%02x", *(tptr)));
 199                         break;
 200                     case 0x14: /* System Name - not documented */
 201                         ND_PRINT((ndo, "'"));
 202                         fn_printn(tptr, len, NULL);
 203                         ND_PRINT((ndo, "'"));
 204                         break;
 205                     case 0x16: /* System Object ID - not documented */
 206                         if (cdp_print_addr(ndo, tptr, len) < 0)
 207                                 goto trunc;
 208                         break;
 209                     case 0x17: /* Physical Location - not documented */
 210                         ND_PRINT((ndo, "0x%02x", *(tptr)));
 211                         if (len > 1) {
 212                                 ND_PRINT((ndo, "/"));
 213                                 fn_printn(tptr + 1, len - 1, NULL);
 214                         }
 215                         break;
 216                     default:
 217                         print_unknown_data(ndo, tptr, "\n\t  ", len);
 218                         break;
 219                     }
 220                 }
 221                 /* avoid infinite loop */
 222                 if (len == 0)
 223                         break;
 224                 tptr = tptr+len;
 225         }
 226         if (ndo->ndo_vflag < 1)
 227             ND_PRINT((ndo, ", length %u", caplen));
 228
 229         return;
 230 trunc:
 231         ND_PRINT((ndo, "%s", tstr));
 232 }
 233
 234 /*
 235  * Protocol type values.
 236  *
 237  * PT_NLPID means that the protocol type field contains an OSI NLPID.
 238  *
 239  * PT_IEEE_802_2 means that the protocol type field contains an IEEE 802.2
 240  * LLC header that specifies that the payload is for that protocol.
 241  */
 242 #define PT_NLPID                1       /* OSI NLPID */
 243 #define PT_IEEE_802_2           2       /* IEEE 802.2 LLC header */
 244
 245 static int
 246 cdp_print_addr(netdissect_options *ndo,
 247                const u_char * p, int l)
 248 {
 249         int pt, pl, al, num;
 250         const u_char *endp = p + l;
 251 #ifdef INET6
 252         static const u_char prot_ipv6[] = {
 253                 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x86, 0xdd
 254         };
 255 #endif
 256
 257         ND_TCHECK2(*p, 2);
 258         num = EXTRACT_32BITS(p);
 259         p += 4;
 260
 261         while (p < endp && num >= 0) {
 262                 ND_TCHECK2(*p, 2);
 263                 if (p + 2 > endp)
 264                         goto trunc;
 265                 pt = p[0];              /* type of "protocol" field */
 266                 pl = p[1];              /* length of "protocol" field */
 267                 p += 2;
 268
 269                 ND_TCHECK2(p[pl], 2);
 270                 if (p + pl + 2 > endp)
 271                         goto trunc;
 272                 al = EXTRACT_16BITS(&p[pl]);    /* address length */
 273
 274                 if (pt == PT_NLPID && pl == 1 && *p == NLPID_IP && al == 4) {
 275                         /*
 276                          * IPv4: protocol type = NLPID, protocol length = 1
 277                          * (1-byte NLPID), protocol = 0xcc (NLPID for IPv4),
 278                          * address length = 4
 279                          */
 280                         p += 3;
 281
 282                         ND_TCHECK2(*p, 4);
 283                         if (p + 4 > endp)
 284                                 goto trunc;
 285                         ND_PRINT((ndo, "IPv4 (%u) %s", num, ipaddr_string(ndo, p)));
 286                         p += 4;
 287                 }
 288 #ifdef INET6
 289                 else if (pt == PT_IEEE_802_2 && pl == 8 &&
 290                     memcmp(p, prot_ipv6, 8) == 0 && al == 16) {
 291                         /*
 292                          * IPv6: protocol type = IEEE 802.2 header,
 293                          * protocol length = 8 (size of LLC+SNAP header),
 294                          * protocol = LLC+SNAP header with the IPv6
 295                          * Ethertype, address length = 16
 296                          */
 297                         p += 10;
 298                         ND_TCHECK2(*p, al);
 299                         if (p + al > endp)
 300                                 goto trunc;
 301
 302                         ND_PRINT((ndo, "IPv6 (%u) %s", num, ip6addr_string(ndo, p)));
 303                         p += al;
 304                 }
 305 #endif
 306                 else {
 307                         /*
 308                          * Generic case: just print raw data
 309                          */
 310                         ND_TCHECK2(*p, pl);
 311                         if (p + pl > endp)
 312                                 goto trunc;
 313                         ND_PRINT((ndo, "pt=0x%02x, pl=%d, pb=", *(p - 2), pl));
 314                         while (pl-- > 0)
 315                                 ND_PRINT((ndo, " %02x", *p++));
 316                         ND_TCHECK2(*p, 2);
 317                         if (p + 2 > endp)
 318                                 goto trunc;
 319                         al = (*p << 8) + *(p + 1);
 320                         ND_PRINT((ndo, ", al=%d, a=", al));
 321                         p += 2;
 322                         ND_TCHECK2(*p, al);
 323                         if (p + al > endp)
 324                                 goto trunc;
 325                         while (al-- > 0)
 326                                 ND_PRINT((ndo, " %02x", *p++));
 327                 }
 328                 num--;
 329                 if (num)
 330                         ND_PRINT((ndo, " "));
 331         }
 332
 333         return 0;
 334
 335 trunc:
 336         return -1;
 337 }
 338
 339
 340 static int
 341 cdp_print_prefixes(netdissect_options *ndo,
 342                    const u_char * p, int l)
 343 {
 344         if (l % 5)
 345                 goto trunc;
 346
 347         ND_PRINT((ndo, " IPv4 Prefixes (%d):", l / 5));
 348
 349         while (l > 0) {
 350                 ND_PRINT((ndo, " %u.%u.%u.%u/%u", p[0], p[1], p[2], p[3], p[4]));
 351                 l -= 5;
 352                 p += 5;
 353         }
 354
 355         return 0;
 356
 357 trunc:
 358         return -1;
 359 }
 360
 361 /* read in a <n>-byte number, MSB first
 362  * (of course this can handle max sizeof(long))
 363  */
 364 static unsigned long cdp_get_number(const u_char * p, int l)
 365 {
 366     unsigned long res=0;
 367     while( l>0 )
 368     {
 369         res = (res<<8) + *p;
 370         p++; l--;
 371     }
 372     return res;
 373 }