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 1.16 2002-08-07 05:21:07 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           const u_char *esrc, const u_char *edst)
  52 {
  53         u_int i;
  54         int type, len;
  55
  56         /* Cisco Discovery Protocol */
  57
  58         if (caplen < 4) {
  59                 (void)printf("[|cdp]");
  60                 return;
  61         }
  62
  63         i = 0;          /* CDP data starts at offset 0 */
  64         printf("CDP v%u, ttl=%us", p[i], p[i + 1]);
  65         i += 4;         /* skip version, TTL and chksum */
  66
  67         while (i < length) {
  68                 if (i + 4 > caplen)
  69                         goto trunc;
  70                 type = (p[i] <<  8) + p[i + 1];
  71                 len  = (p[i + 2] << 8) + p[i + 3];
  72
  73                 if (vflag > 1)
  74                         printf("\n\t");
  75
  76                 if (vflag)
  77                         printf(" %02x/%02x", type, len);
  78
  79                 if (i + len > caplen)
  80                         goto trunc;
  81
  82                 switch (type) {
  83                 case 0x00:
  84                         printf(" Goodbye");
  85                         break;
  86                 case 0x01:
  87                         printf(" DevID '%.*s'", len - 4, p + i + 4);
  88                         break;
  89                 case 0x02:
  90                         printf(" Addr");
  91                         if (cdp_print_addr(p + i + 4, len - 4) < 0)
  92                                 goto trunc;
  93                         break;
  94                 case 0x03:
  95                         printf(" PortID '%.*s'", len - 4, p + i + 4);
  96                         break;
  97                 case 0x04:
  98                         printf(" CAP 0x%02x", (unsigned) p[i + 7]);
  99                         break;
 100                 case 0x05:
 101                         if (vflag > 1)
 102                                 printf(" Version:\n%.*s", len - 4, p + i + 4);
 103                         else
 104                                 printf(" Version: (suppressed)");
 105                         break;
 106                 case 0x06:
 107                         printf(" Platform: '%.*s'", len - 4, p + i + 4);
 108                         break;
 109                 case 0x07:
 110                         if (cdp_print_prefixes(p + i + 4, len - 4) < 0)
 111                                 goto trunc;
 112                         break;
 113                 case 0x08:              /* guess - not documented */
 114                         printf(" Protocol-Hello option" );
 115                         break;
 116                 case 0x09:              /* guess - not documented */
 117                         printf(" VTP Management Domain: '%.*s'", len - 4,
 118                             p + i + 4);
 119                         break;
 120                 case 0x0a:              /* guess - not documented */
 121                         printf(" Native VLAN ID: %d",
 122                             (p[i + 4] << 8) + p[i + 4 + 1] );
 123                         break;
 124                 case 0x0b:              /* guess - not documented */
 125                         printf(" Duplex: %s", p[i + 4] ? "full": "half");
 126                         break;
 127 /* http://www.cisco.com/univercd/cc/td/doc/product/voice/ata/atarn/186rn21m.htm
 128  * plus more details from other sources
 129  */
 130                 case 0x0e:              /* incomplete doc. */
 131                         printf(" ATA-186 VoIP VLAN request, app %d, vlan %d",
 132                                 p[i + 4], EXTRACT_16BITS(&p[i+4+1]));
 133                         break;
 134                 case 0x0f:              /* incomplete doc. */
 135                         printf(" ATA-186 VoIP VLAN assignment" );
 136                         break;
 137                 case 0x10:              /* incomplete doc. */
 138                         printf(" power consumption: %1.2fW",
 139                                 cdp_get_number(p+i+4, len-4)/1000.0 );
 140                         break;
 141                 case 0x11:              /* guess - not documented */
 142                         printf(" MTU %u bytes", EXTRACT_32BITS(&p[i+4]));
 143                         break;
 144                 case 0x12:              /* guess - not documented */
 145                         printf(" AVVID trust bitmap 0x%02x", p[i+4] );
 146                         break;
 147                 case 0x13:              /* guess - not documented */
 148                         printf(" AVVID untrusted ports CoS: 0x%02x", p[i+4]);
 149                         break;
 150                 case 0x14:              /* guess - not documented */
 151                         printf(" System Name: '%.*s'", len - 4,
 152                                 p + i + 4);
 153                         break;
 154                 case 0x15:              /* guess - not documented */
 155                         printf(" System Object ID (not decoded) ");     /* TODO */
 156                         break;
 157                 case 0x16:              /* guess - not documented */
 158                         printf(" Management Addresses: ");
 159                         if (cdp_print_addr(p + i + 4, len - 4) < 0)
 160                                 goto trunc;
 161                         break;
 162                 case 0x17:              /* guess - not documented */
 163                         printf(" Physical Location: 0x%02x/%.*s",
 164                                 p[i+4], len - 5, p + i + 5 );
 165                         break;
 166                 default:
 167                         printf(" unknown field type %02x, len %d", type, len);
 168                         break;
 169                 }
 170
 171                 /* avoid infinite loop */
 172                 if (len == 0)
 173                         break;
 174                 i += len;
 175         }
 176
 177         return;
 178
 179 trunc:
 180         printf("[|cdp]");
 181 }
 182
 183 /*
 184  * Protocol type values.
 185  *
 186  * PT_NLPID means that the protocol type field contains an OSI NLPID.
 187  *
 188  * PT_IEEE_802_2 means that the protocol type field contains an IEEE 802.2
 189  * LLC header that specifies that the payload is for that protocol.
 190  */
 191 #define PT_NLPID                1       /* OSI NLPID */
 192 #define PT_IEEE_802_2           2       /* IEEE 802.2 LLC header */
 193
 194 static int
 195 cdp_print_addr(const u_char * p, int l)
 196 {
 197         int pt, pl, al, num;
 198         const u_char *endp = p + l;
 199 #ifdef INET6
 200         static u_char prot_ipv6[] = {
 201                 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x86, 0xdd
 202         };
 203 #endif
 204
 205         num = EXTRACT_32BITS(p);
 206         p += 4;
 207
 208         printf(" (%d): ", num);
 209
 210         while (p < endp && num >= 0) {
 211                 if (p + 2 > endp)
 212                         goto trunc;
 213                 pt = p[0];              /* type of "protocol" field */
 214                 pl = p[1];              /* length of "protocol" field */
 215                 p += 2;
 216
 217                 if (p + pl + 2 > endp)
 218                         goto trunc;
 219                 al = EXTRACT_16BITS(&p[pl]);    /* address length */
 220
 221                 if (pt == PT_NLPID && pl == 1 && *p == 0xcc && al == 4) {
 222                         /*
 223                          * IPv4: protocol type = NLPID, protocol length = 1
 224                          * (1-byte NLPID), protocol = 0xcc (NLPID for IPv4),
 225                          * address length = 4
 226                          */
 227                         p += 3;
 228
 229                         if (p + 4 > endp)
 230                                 goto trunc;
 231                         printf("IPv4 %u.%u.%u.%u", p[0], p[1], p[2], p[3]);
 232                         p += 4;
 233                 }
 234 #ifdef INET6
 235                 else if (pt == PT_IEEE_802_2 && pl == 8 &&
 236                     memcmp(p, prot_ipv6, 8) == 0 && al == 16) {
 237                         /*
 238                          * IPv6: protocol type = IEEE 802.2 header,
 239                          * protocol length = 8 (size of LLC+SNAP header),
 240                          * protocol = LLC+SNAP header with the IPv6
 241                          * Ethertype, address length = 16
 242                          */
 243                         p += 10;
 244                         if (p + al > endp)
 245                                 goto trunc;
 246
 247                         printf("IPv6 %s", ip6addr_string(p));
 248                         p += al;
 249                 }
 250 #endif
 251                 else {
 252                         /*
 253                          * Generic case: just print raw data
 254                          */
 255                         if (p + pl > endp)
 256                                 goto trunc;
 257                         printf("pt=0x%02x, pl=%d, pb=", *(p - 2), pl);
 258                         while (pl-- > 0)
 259                                 printf(" %02x", *p++);
 260                         if (p + 2 > endp)
 261                                 goto trunc;
 262                         al = (*p << 8) + *(p + 1);
 263                         printf(", al=%d, a=", al);
 264                         p += 2;
 265                         if (p + al > endp)
 266                                 goto trunc;
 267                         while (al-- > 0)
 268                                 printf(" %02x", *p++);
 269                 }
 270                 num--;
 271                 if (num)
 272                         printf(" ");
 273         }
 274
 275         return 0;
 276
 277 trunc:
 278         return -1;
 279 }
 280
 281
 282 static int
 283 cdp_print_prefixes(const u_char * p, int l)
 284 {
 285         if (l % 5)
 286                 goto trunc;
 287
 288         printf(" IPv4 Prefixes (%d):", l / 5);
 289
 290         while (l > 0) {
 291                 printf(" %u.%u.%u.%u/%u", p[0], p[1], p[2], p[3], p[4]);
 292                 l -= 5;
 293                 p += 5;
 294         }
 295
 296         return 0;
 297
 298 trunc:
 299         return -1;
 300 }
 301
 302 /* read in a <n>-byte number, MSB first
 303  * (of course this can handle max sizeof(long))
 304  */
 305 static unsigned long cdp_get_number(const u_char * p, int l)
 306 {
 307     unsigned long res=0;
 308     while( l>0 )
 309     {
 310         res = (res<<8) + *p;
 311         p++; l--;
 312     }
 313     return res;
 314 }