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 #ifndef lint
  28 static const char rcsid[] =
  29     "@(#) $Header: /tcpdump/master/tcpdump/print-cdp.c,v 1.17 2002-09-05 21:25:38 guy Exp $";
  30 #endif
  31
  32 #ifdef HAVE_CONFIG_H
  33 #include "config.h"
  34 #endif
  35
  36 #include <tcpdump-stdinc.h>
  37
  38 #include <stdio.h>
  39 #include <string.h>
  40
  41 #include "interface.h"
  42 #include "addrtoname.h"
  43 #include "extract.h"                    /* must come after interface.h */
  44
  45 static int cdp_print_addr(const u_char *, int);
  46 static int cdp_print_prefixes(const u_char *, int);
  47 static unsigned long cdp_get_number(const u_char *, int);
  48
  49 void
  50 cdp_print(const u_char *p, u_int length, u_int caplen)
  51 {
  52         u_int i;
  53         int type, len;
  54
  55         /* Cisco Discovery Protocol */
  56
  57         if (caplen < 4) {
  58                 (void)printf("[|cdp]");
  59                 return;
  60         }
  61
  62         i = 0;          /* CDP data starts at offset 0 */
  63         printf("CDP v%u, ttl=%us", p[i], p[i + 1]);
  64         i += 4;         /* skip version, TTL and chksum */
  65
  66         while (i < length) {
  67                 if (i + 4 > caplen)
  68                         goto trunc;
  69                 type = (p[i] <<  8) + p[i + 1];
  70                 len  = (p[i + 2] << 8) + p[i + 3];
  71
  72                 if (vflag > 1)
  73                         printf("\n\t");
  74
  75                 if (vflag)
  76                         printf(" %02x/%02x", type, len);
  77
  78                 if (i + len > caplen)
  79                         goto trunc;
  80
  81                 switch (type) {
  82                 case 0x00:
  83                         printf(" Goodbye");
  84                         break;
  85                 case 0x01:
  86                         printf(" DevID '%.*s'", len - 4, p + i + 4);
  87                         break;
  88                 case 0x02:
  89                         printf(" Addr");
  90                         if (cdp_print_addr(p + i + 4, len - 4) < 0)
  91                                 goto trunc;
  92                         break;
  93                 case 0x03:
  94                         printf(" PortID '%.*s'", len - 4, p + i + 4);
  95                         break;
  96                 case 0x04:
  97                         printf(" CAP 0x%02x", (unsigned) p[i + 7]);
  98                         break;
  99                 case 0x05:
 100                         if (vflag > 1)
 101                                 printf(" Version:\n%.*s", len - 4, p + i + 4);
 102                         else
 103                                 printf(" Version: (suppressed)");
 104                         break;
 105                 case 0x06:
 106                         printf(" Platform: '%.*s'", len - 4, p + i + 4);
 107                         break;
 108                 case 0x07:
 109                         if (cdp_print_prefixes(p + i + 4, len - 4) < 0)
 110                                 goto trunc;
 111                         break;
 112                 case 0x08:              /* guess - not documented */
 113                         printf(" Protocol-Hello option" );
 114                         break;
 115                 case 0x09:              /* guess - not documented */
 116                         printf(" VTP Management Domain: '%.*s'", len - 4,
 117                             p + i + 4);
 118                         break;
 119                 case 0x0a:              /* guess - not documented */
 120                         printf(" Native VLAN ID: %d",
 121                             (p[i + 4] << 8) + p[i + 4 + 1] );
 122                         break;
 123                 case 0x0b:              /* guess - not documented */
 124                         printf(" Duplex: %s", p[i + 4] ? "full": "half");
 125                         break;
 126 /* http://www.cisco.com/univercd/cc/td/doc/product/voice/ata/atarn/186rn21m.htm
 127  * plus more details from other sources
 128  */
 129                 case 0x0e:              /* incomplete doc. */
 130                         printf(" ATA-186 VoIP VLAN request, app %d, vlan %d",
 131                                 p[i + 4], EXTRACT_16BITS(&p[i+4+1]));
 132                         break;
 133                 case 0x0f:              /* incomplete doc. */
 134                         printf(" ATA-186 VoIP VLAN assignment" );
 135                         break;
 136                 case 0x10:              /* incomplete doc. */
 137                         printf(" power consumption: %1.2fW",
 138                                 cdp_get_number(p+i+4, len-4)/1000.0 );
 139                         break;
 140                 case 0x11:              /* guess - not documented */
 141                         printf(" MTU %u bytes", EXTRACT_32BITS(&p[i+4]));
 142                         break;
 143                 case 0x12:              /* guess - not documented */
 144                         printf(" AVVID trust bitmap 0x%02x", p[i+4] );
 145                         break;
 146                 case 0x13:              /* guess - not documented */
 147                         printf(" AVVID untrusted ports CoS: 0x%02x", p[i+4]);
 148                         break;
 149                 case 0x14:              /* guess - not documented */
 150                         printf(" System Name: '%.*s'", len - 4,
 151                                 p + i + 4);
 152                         break;
 153                 case 0x15:              /* guess - not documented */
 154                         printf(" System Object ID (not decoded) ");     /* TODO */
 155                         break;
 156                 case 0x16:              /* guess - not documented */
 157                         printf(" Management Addresses: ");
 158                         if (cdp_print_addr(p + i + 4, len - 4) < 0)
 159                                 goto trunc;
 160                         break;
 161                 case 0x17:              /* guess - not documented */
 162                         printf(" Physical Location: 0x%02x/%.*s",
 163                                 p[i+4], len - 5, p + i + 5 );
 164                         break;
 165                 default:
 166                         printf(" unknown field type %02x, len %d", type, len);
 167                         break;
 168                 }
 169
 170                 /* avoid infinite loop */
 171                 if (len == 0)
 172                         break;
 173                 i += len;
 174         }
 175
 176         return;
 177
 178 trunc:
 179         printf("[|cdp]");
 180 }
 181
 182 /*
 183  * Protocol type values.
 184  *
 185  * PT_NLPID means that the protocol type field contains an OSI NLPID.
 186  *
 187  * PT_IEEE_802_2 means that the protocol type field contains an IEEE 802.2
 188  * LLC header that specifies that the payload is for that protocol.
 189  */
 190 #define PT_NLPID                1       /* OSI NLPID */
 191 #define PT_IEEE_802_2           2       /* IEEE 802.2 LLC header */
 192
 193 static int
 194 cdp_print_addr(const u_char * p, int l)
 195 {
 196         int pt, pl, al, num;
 197         const u_char *endp = p + l;
 198 #ifdef INET6
 199         static u_char prot_ipv6[] = {
 200                 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x86, 0xdd
 201         };
 202 #endif
 203
 204         num = EXTRACT_32BITS(p);
 205         p += 4;
 206
 207         printf(" (%d): ", num);
 208
 209         while (p < endp && num >= 0) {
 210                 if (p + 2 > endp)
 211                         goto trunc;
 212                 pt = p[0];              /* type of "protocol" field */
 213                 pl = p[1];              /* length of "protocol" field */
 214                 p += 2;
 215
 216                 if (p + pl + 2 > endp)
 217                         goto trunc;
 218                 al = EXTRACT_16BITS(&p[pl]);    /* address length */
 219
 220                 if (pt == PT_NLPID && pl == 1 && *p == 0xcc && al == 4) {
 221                         /*
 222                          * IPv4: protocol type = NLPID, protocol length = 1
 223                          * (1-byte NLPID), protocol = 0xcc (NLPID for IPv4),
 224                          * address length = 4
 225                          */
 226                         p += 3;
 227
 228                         if (p + 4 > endp)
 229                                 goto trunc;
 230                         printf("IPv4 %u.%u.%u.%u", p[0], p[1], p[2], p[3]);
 231                         p += 4;
 232                 }
 233 #ifdef INET6
 234                 else if (pt == PT_IEEE_802_2 && pl == 8 &&
 235                     memcmp(p, prot_ipv6, 8) == 0 && al == 16) {
 236                         /*
 237                          * IPv6: protocol type = IEEE 802.2 header,
 238                          * protocol length = 8 (size of LLC+SNAP header),
 239                          * protocol = LLC+SNAP header with the IPv6
 240                          * Ethertype, address length = 16
 241                          */
 242                         p += 10;
 243                         if (p + al > endp)
 244                                 goto trunc;
 245
 246                         printf("IPv6 %s", ip6addr_string(p));
 247                         p += al;
 248                 }
 249 #endif
 250                 else {
 251                         /*
 252                          * Generic case: just print raw data
 253                          */
 254                         if (p + pl > endp)
 255                                 goto trunc;
 256                         printf("pt=0x%02x, pl=%d, pb=", *(p - 2), pl);
 257                         while (pl-- > 0)
 258                                 printf(" %02x", *p++);
 259                         if (p + 2 > endp)
 260                                 goto trunc;
 261                         al = (*p << 8) + *(p + 1);
 262                         printf(", al=%d, a=", al);
 263                         p += 2;
 264                         if (p + al > endp)
 265                                 goto trunc;
 266                         while (al-- > 0)
 267                                 printf(" %02x", *p++);
 268                 }
 269                 num--;
 270                 if (num)
 271                         printf(" ");
 272         }
 273
 274         return 0;
 275
 276 trunc:
 277         return -1;
 278 }
 279
 280
 281 static int
 282 cdp_print_prefixes(const u_char * p, int l)
 283 {
 284         if (l % 5)
 285                 goto trunc;
 286
 287         printf(" IPv4 Prefixes (%d):", l / 5);
 288
 289         while (l > 0) {
 290                 printf(" %u.%u.%u.%u/%u", p[0], p[1], p[2], p[3], p[4]);
 291                 l -= 5;
 292                 p += 5;
 293         }
 294
 295         return 0;
 296
 297 trunc:
 298         return -1;
 299 }
 300
 301 /* read in a <n>-byte number, MSB first
 302  * (of course this can handle max sizeof(long))
 303  */
 304 static unsigned long cdp_get_number(const u_char * p, int l)
 305 {
 306     unsigned long res=0;
 307     while( l>0 )
 308     {
 309         res = (res<<8) + *p;
 310         p++; l--;
 311     }
 312     return res;
 313 }