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 <tcpdump-stdinc.h>
  32
  33 #include <stdio.h>
  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(const u_char *, int);
  82 static int cdp_print_prefixes(const u_char *, int);
  83 static unsigned long cdp_get_number(const u_char *, int);
  84
  85 void
  86 cdp_print(const u_char *pptr, u_int length, u_int caplen)
  87 {
  88         int type, len, i, j;
  89         const u_char *tptr;
  90
  91         if (caplen < CDP_HEADER_LEN) {
  92                 printf("%s", tstr);
  93                 return;
  94         }
  95
  96         tptr = pptr; /* temporary pointer */
  97
  98         if (!TTEST2(*tptr, CDP_HEADER_LEN))
  99                 goto trunc;
 100         printf("CDPv%u, ttl: %us", *tptr, *(tptr+1));
 101         if (vflag)
 102                 printf(", checksum: %u (unverified), length %u", EXTRACT_16BITS(tptr), length);
 103         tptr += CDP_HEADER_LEN;
 104
 105         while (tptr < (pptr+length)) {
 106
 107                 if (!TTEST2(*tptr, 4)) /* read out Type and Length */
 108                     goto trunc;
 109                 type = EXTRACT_16BITS(tptr);
 110                 len  = EXTRACT_16BITS(tptr+2); /* object length includes the 4 bytes header length */
 111                 tptr += 4;
 112                 len -= 4;
 113
 114                 if (!TTEST2(*tptr, len))
 115                         goto trunc;
 116
 117                 if (vflag || type == 1) { /* in non-verbose mode just print Device-ID */
 118
 119                     if (vflag)
 120                         printf("\n\t%s (0x%02x), length: %u byte%s: ",
 121                                tok2str(cdp_tlv_values,"unknown field type", type),
 122                                type,
 123                                len,
 124                                PLURAL_SUFFIX(len)); /* plural */
 125
 126                     switch (type) {
 127
 128                     case 0x01: /* Device-ID */
 129                         if (!vflag)
 130                             printf(", Device-ID ");
 131                         printf("'");
 132                         fn_printn(tptr, len, NULL);
 133                         printf("'");
 134                         break;
 135                     case 0x02: /* Address */
 136                         if (cdp_print_addr(tptr, len) < 0)
 137                             goto trunc;
 138                         break;
 139                     case 0x03: /* Port-ID */
 140                         printf("'");
 141                         fn_printn(tptr, len, NULL);
 142                         printf("'");
 143                         break;
 144                     case 0x04: /* Capabilities */
 145                         printf("(0x%08x): %s",
 146                                EXTRACT_32BITS(tptr),
 147                                bittok2str(cdp_capability_values, "none",EXTRACT_32BITS(tptr)));
 148                         break;
 149                     case 0x05: /* Version */
 150                         printf("\n\t  ");
 151                         for (i=0;i<len;i++) {
 152                             j = *(tptr+i);
 153                             putchar(j);
 154                             if (j == 0x0a) /* lets rework the version string to get a nice identation */
 155                                 printf("\t  ");
 156                         }
 157                         break;
 158                     case 0x06: /* Platform */
 159                         printf("'");
 160                         fn_printn(tptr, len, NULL);
 161                         printf("'");
 162                         break;
 163                     case 0x07: /* Prefixes */
 164                         if (cdp_print_prefixes(tptr, len) < 0)
 165                             goto trunc;
 166                         break;
 167                     case 0x08: /* Protocol Hello Option - not documented */
 168                         break;
 169                     case 0x09: /* VTP Mgmt Domain  - not documented */
 170                         printf("'");
 171                         fn_printn(tptr, len, NULL);
 172                         printf("'");
 173                         break;
 174                     case 0x0a: /* Native VLAN ID - not documented */
 175                         printf("%d",EXTRACT_16BITS(tptr));
 176                         break;
 177                     case 0x0b: /* Duplex - not documented */
 178                         printf("%s", *(tptr) ? "full": "half");
 179                         break;
 180
 181                     /* http://www.cisco.com/univercd/cc/td/doc/product/voice/ata/atarn/186rn21m.htm
 182                      * plus more details from other sources
 183                      */
 184                     case 0x0e: /* ATA-186 VoIP VLAN request - incomplete doc. */
 185                         printf("app %d, vlan %d",
 186                                *(tptr), EXTRACT_16BITS(tptr+1));
 187                         break;
 188                     case 0x10: /* ATA-186 VoIP VLAN assignment - incomplete doc. */
 189                         printf("%1.2fW",
 190                                cdp_get_number(tptr, len)/1000.0 );
 191                         break;
 192                     case 0x11: /* MTU - not documented */
 193                         printf("%u bytes", EXTRACT_32BITS(tptr));
 194                         break;
 195                     case 0x12: /* AVVID trust bitmap - not documented */
 196                         printf("0x%02x", *(tptr) );
 197                         break;
 198                     case 0x13: /* AVVID untrusted port CoS - not documented */
 199                         printf("0x%02x", *(tptr));
 200                         break;
 201                     case 0x14: /* System Name - not documented */
 202                         printf("'");
 203                         fn_printn(tptr, len, NULL);
 204                         printf("'");
 205                         break;
 206                     case 0x16: /* System Object ID - not documented */
 207                         if (cdp_print_addr(tptr, len) < 0)
 208                                 goto trunc;
 209                         break;
 210                     case 0x17: /* Physical Location - not documented */
 211                         printf("0x%02x", *(tptr));
 212                         if (len > 1) {
 213                                 printf("/");
 214                                 fn_printn(tptr + 1, len - 1, NULL);
 215                         }
 216                         break;
 217                     default:
 218                         print_unknown_data(gndo,tptr,"\n\t  ",len);
 219                         break;
 220                     }
 221                 }
 222                 /* avoid infinite loop */
 223                 if (len == 0)
 224                         break;
 225                 tptr = tptr+len;
 226         }
 227         if (vflag < 1)
 228             printf(", length %u",caplen);
 229
 230         return;
 231 trunc:
 232         printf("%s", tstr);
 233 }
 234
 235 /*
 236  * Protocol type values.
 237  *
 238  * PT_NLPID means that the protocol type field contains an OSI NLPID.
 239  *
 240  * PT_IEEE_802_2 means that the protocol type field contains an IEEE 802.2
 241  * LLC header that specifies that the payload is for that protocol.
 242  */
 243 #define PT_NLPID                1       /* OSI NLPID */
 244 #define PT_IEEE_802_2           2       /* IEEE 802.2 LLC header */
 245
 246 static int
 247 cdp_print_addr(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         TCHECK2(*p, 2);
 258         num = EXTRACT_32BITS(p);
 259         p += 4;
 260
 261         while (p < endp && num >= 0) {
 262                 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                 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                         TCHECK2(*p, 4);
 283                         if (p + 4 > endp)
 284                                 goto trunc;
 285                         printf("IPv4 (%u) %s",
 286                                num,
 287                                ipaddr_string(p));
 288                         p += 4;
 289                 }
 290 #ifdef INET6
 291                 else if (pt == PT_IEEE_802_2 && pl == 8 &&
 292                     memcmp(p, prot_ipv6, 8) == 0 && al == 16) {
 293                         /*
 294                          * IPv6: protocol type = IEEE 802.2 header,
 295                          * protocol length = 8 (size of LLC+SNAP header),
 296                          * protocol = LLC+SNAP header with the IPv6
 297                          * Ethertype, address length = 16
 298                          */
 299                         p += 10;
 300                         TCHECK2(*p, al);
 301                         if (p + al > endp)
 302                                 goto trunc;
 303
 304                         printf("IPv6 (%u) %s",
 305                                num,
 306                                ip6addr_string(p));
 307                         p += al;
 308                 }
 309 #endif
 310                 else {
 311                         /*
 312                          * Generic case: just print raw data
 313                          */
 314                         TCHECK2(*p, pl);
 315                         if (p + pl > endp)
 316                                 goto trunc;
 317                         printf("pt=0x%02x, pl=%d, pb=", *(p - 2), pl);
 318                         while (pl-- > 0)
 319                                 printf(" %02x", *p++);
 320                         TCHECK2(*p, 2);
 321                         if (p + 2 > endp)
 322                                 goto trunc;
 323                         al = (*p << 8) + *(p + 1);
 324                         printf(", al=%d, a=", al);
 325                         p += 2;
 326                         TCHECK2(*p, al);
 327                         if (p + al > endp)
 328                                 goto trunc;
 329                         while (al-- > 0)
 330                                 printf(" %02x", *p++);
 331                 }
 332                 num--;
 333                 if (num)
 334                         printf(" ");
 335         }
 336
 337         return 0;
 338
 339 trunc:
 340         return -1;
 341 }
 342
 343
 344 static int
 345 cdp_print_prefixes(const u_char * p, int l)
 346 {
 347         if (l % 5)
 348                 goto trunc;
 349
 350         printf(" IPv4 Prefixes (%d):", l / 5);
 351
 352         while (l > 0) {
 353                 printf(" %u.%u.%u.%u/%u", p[0], p[1], p[2], p[3], p[4]);
 354                 l -= 5;
 355                 p += 5;
 356         }
 357
 358         return 0;
 359
 360 trunc:
 361         return -1;
 362 }
 363
 364 /* read in a <n>-byte number, MSB first
 365  * (of course this can handle max sizeof(long))
 366  */
 367 static unsigned long cdp_get_number(const u_char * p, int l)
 368 {
 369     unsigned long res=0;
 370     while( l>0 )
 371     {
 372         res = (res<<8) + *p;
 373         p++; l--;
 374     }
 375     return res;
 376 }