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 1.13 2002-04-26 09:51:34 guy Exp $";
  30 #endif
  31
  32 #ifdef HAVE_CONFIG_H
  33 #include "config.h"
  34 #endif
  35
  36 #include <sys/param.h>
  37 #include <sys/time.h>
  38
  39 #include <netinet/in.h>
  40
  41 #include <ctype.h>
  42 #include <netdb.h>
  43 #include <stdio.h>
  44 #include <string.h>
  45
  46 #include "interface.h"
  47 #include "addrtoname.h"
  48 #include "extract.h"                    /* must come after interface.h */
  49
  50 static int cdp_print_addr(const u_char *, int);
  51 static int cdp_print_prefixes(const u_char *, int);
  52 static unsigned long cdp_get_number(const u_char *, int);
  53
  54 void
  55 cdp_print(const u_char *p, u_int length, u_int caplen,
  56           const u_char *esrc, const u_char *edst)
  57 {
  58         u_int i;
  59         int type, len;
  60
  61         /* Cisco Discovery Protocol */
  62
  63         if (caplen < 4) {
  64                 (void)printf("[|cdp]");
  65                 return;
  66         }
  67
  68         i = 0;          /* CDP data starts at offset 0 */
  69         printf("CDP v%u, ttl=%us", p[i], p[i + 1]);
  70         i += 4;         /* skip version, TTL and chksum */
  71
  72         while (i < length) {
  73                 if (i + 4 > caplen)
  74                         goto trunc;
  75                 type = (p[i] <<  8) + p[i + 1];
  76                 len  = (p[i + 2] << 8) + p[i + 3];
  77
  78                 if (vflag > 1)
  79                         printf("\n\t");
  80
  81                 if (vflag)
  82                         printf(" %02x/%02x", type, len);
  83
  84                 if (i + len > caplen)
  85                         goto trunc;
  86
  87                 switch (type) {
  88                 case 0x00:
  89                         printf(" Goodbye");
  90                         break;
  91                 case 0x01:
  92                         printf(" DevID '%.*s'", len - 4, p + i + 4);
  93                         break;
  94                 case 0x02:
  95                         printf(" Addr");
  96                         if (cdp_print_addr(p + i + 4, len - 4) < 0)
  97                                 goto trunc;
  98                         break;
  99                 case 0x03:
 100                         printf(" PortID '%.*s'", len - 4, p + i + 4);
 101                         break;
 102                 case 0x04:
 103                         printf(" CAP 0x%02x", (unsigned) p[i + 7]);
 104                         break;
 105                 case 0x05:
 106                         if (vflag > 1)
 107                                 printf(" Version:\n%.*s", len - 4, p + i + 4);
 108                         else
 109                                 printf(" Version: (suppressed)");
 110                         break;
 111                 case 0x06:
 112                         printf(" Platform: '%.*s'", len - 4, p + i + 4);
 113                         break;
 114                 case 0x07:
 115                         if (cdp_print_prefixes(p + i + 4, len - 4) < 0)
 116                                 goto trunc;
 117                         break;
 118                 case 0x08:              /* guess - not documented */
 119                         printf(" Protocol-Hello option" );
 120                         break;
 121                 case 0x09:              /* guess - not documented */
 122                         printf(" VTP Management Domain: '%.*s'", len - 4,
 123                             p + i + 4);
 124                         break;
 125                 case 0x0a:              /* guess - not documented */
 126                         printf(" Native VLAN ID: %d",
 127                             (p[i + 4] << 8) + p[i + 4 + 1] );
 128                         break;
 129                 case 0x0b:              /* guess - not documented */
 130                         printf(" Duplex: %s", p[i + 4] ? "full": "half");
 131                         break;
 132 /* http://www.cisco.com/univercd/cc/td/doc/product/voice/ata/atarn/186rn21m.htm
 133  * plus more details from other sources
 134  */
 135                 case 0x0e:              /* incomplete doc. */
 136                         printf(" ATA-186 VoIP VLAN request, app %d, vlan %d",
 137                                 p[i + 4], EXTRACT_16BITS(&p[i+4+1]));
 138                         break;
 139                 case 0x0f:              /* incomplete doc. */
 140                         printf(" ATA-186 VoIP VLAN assignment" );
 141                         break;
 142                 case 0x10:              /* incomplete doc. */
 143                         printf(" power consumption: %1.2fW",
 144                                 cdp_get_number(p+i+4, len-4)/1000.0 );
 145                         break;
 146                 case 0x11:              /* guess - not documented */
 147                         printf(" MTU %u bytes", EXTRACT_32BITS(&p[i+4]));
 148                         break;
 149                 case 0x12:              /* guess - not documented */
 150                         printf(" AVVID trust bitmap 0x%02x", p[i+4] );
 151                         break;
 152                 case 0x13:              /* guess - not documented */
 153                         printf(" AVVID untrusted ports CoS: 0x%02x", p[i+4]);
 154                         break;
 155                 case 0x14:              /* guess - not documented */
 156                         printf(" sysName='%.*s'", len - 4, p + i + 4 );
 157                         break;
 158                 case 0x15:              /* guess - not documented */
 159                         printf(" sysObjectID" );                /* TODO */
 160                         break;
 161                 case 0x16:              /* guess - not documented */
 162                         printf(" management address(es)" );
 163                         break;
 164                 case 0x17:              /* guess - not documented */
 165                         printf(" phys. location 0x%02x/%.*s",
 166                                 p[i+4], len - 5, p + i + 5 );
 167                         break;
 168                 default:
 169                         printf(" unknown field type %02x, len %d", type, len);
 170                         break;
 171                 }
 172
 173                 /* avoid infinite loop */
 174                 if (len == 0)
 175                         break;
 176                 i += len;
 177         }
 178
 179         return;
 180
 181 trunc:
 182         printf("[|cdp]");
 183 }
 184
 185 /*
 186  * Protocol type values.
 187  *
 188  * PT_NLPID means that the protocol type field contains an OSI NLPID.
 189  *
 190  * PT_IEEE_802_2 means that the protocol type field contains an IEEE 802.2
 191  * LLC header that specifies that the payload is for that protocol.
 192  */
 193 #define PT_NLPID                1       /* OSI NLPID */
 194 #define PT_IEEE_802_2           2       /* IEEE 802.2 LLC header */
 195
 196 static int
 197 cdp_print_addr(const u_char * p, int l)
 198 {
 199         int pt, pl, al, num;
 200         const u_char *endp = p + l;
 201 #ifdef INET6
 202         static u_char prot_ipv6[] = {
 203                 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x86, 0xdd
 204         };
 205 #endif
 206
 207         num = EXTRACT_32BITS(p);
 208         p += 4;
 209
 210         printf(" (%d): ", num);
 211
 212         while (p < endp && num >= 0) {
 213                 if (p + 2 > endp)
 214                         goto trunc;
 215                 pt = p[0];              /* type of "protocol" field */
 216                 pl = p[1];              /* length of "protocol" field */
 217                 p += 2;
 218
 219                 if (p + pl + 2 > endp)
 220                         goto trunc;
 221                 al = EXTRACT_16BITS(&p[pl]);    /* address length */
 222
 223                 if (pt == PT_NLPID && pl == 1 && *p == 0xcc && al == 4) {
 224                         /*
 225                          * IPv4: protocol type = NLPID, protocol length = 1
 226                          * (1-byte NLPID), protocol = 0xcc (NLPID for IPv4),
 227                          * address length = 4
 228                          */
 229                         p += 3;
 230
 231                         if (p + 4 > endp)
 232                                 goto trunc;
 233                         printf("IPv4 %u.%u.%u.%u", p[0], p[1], p[2], p[3]);
 234                         p += 4;
 235                 }
 236 #ifdef INET6
 237                 else if (pt == PT_IEEE_802_2 && pl == 8 &&
 238                     memcmp(p, prot_ipv6, 8) == 0 && al == 16) {
 239                         /*
 240                          * IPv6: protocol type = IEEE 802.2 header,
 241                          * protocol length = 8 (size of LLC+SNAP header),
 242                          * protocol = LLC+SNAP header with the IPv6
 243                          * Ethertype, address length = 16
 244                          */
 245                         p += 10;
 246                         if (p + al > endp)
 247                                 goto trunc;
 248
 249                         printf("IPv6 %s", ip6addr_string(p));
 250                         p += al;
 251                 }
 252 #endif
 253                 else {
 254                         /*
 255                          * Generic case: just print raw data
 256                          */
 257                         if (p + pl > endp)
 258                                 goto trunc;
 259                         printf("pt=0x%02x, pl=%d, pb=", *(p - 2), pl);
 260                         while (pl-- > 0)
 261                                 printf(" %02x", *p++);
 262                         if (p + 2 > endp)
 263                                 goto trunc;
 264                         al = (*p << 8) + *(p + 1);
 265                         printf(", al=%d, a=", al);
 266                         p += 2;
 267                         if (p + al > endp)
 268                                 goto trunc;
 269                         while (al-- > 0)
 270                                 printf(" %02x", *p++);
 271                 }
 272                 num--;
 273                 if (num)
 274                         printf(" ");
 275         }
 276
 277         return 0;
 278
 279 trunc:
 280         return -1;
 281 }
 282
 283
 284 static int
 285 cdp_print_prefixes(const u_char * p, int l)
 286 {
 287         if (l % 5)
 288                 goto trunc;
 289
 290         printf(" IPv4 Prefixes (%d):", l / 5);
 291
 292         while (l > 0) {
 293                 printf(" %u.%u.%u.%u/%u", p[0], p[1], p[2], p[3], p[4]);
 294                 l -= 5;
 295                 p += 5;
 296         }
 297
 298         return 0;
 299
 300 trunc:
 301         return -1;
 302 }
 303
 304 /* read in a <n>-byte number, MSB first
 305  * (of course this can handle max sizeof(long))
 306  */
 307 static unsigned long cdp_get_number(const u_char * p, int l)
 308 {
 309     unsigned long res=0;
 310     while( l>0 )
 311     {
 312         res = (res<<8) + *p;
 313         p++; l--;
 314     }
 315     return res;
 316 }