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 1.4 2000-07-29 07:27:54 assar 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 void cdp_print_addr( const u_char * p, int l );
  51 static void cdp_print_prefixes( const u_char * p, int l );
  52
  53 /*
  54  * Returns non-zero IFF it succeeds in printing the header
  55  */
  56 void
  57 cdp_print(const u_char *p, u_int length, u_int caplen,
  58           const u_char *esrc, const u_char *edst)
  59 {
  60         int i;
  61         int type, len;
  62
  63         /* Cisco Discovery Protocol */
  64
  65
  66         if ( caplen < 12 ) {
  67                 (void)printf("[|cdp]");
  68                 return;
  69         }
  70
  71         i=8;            /* CDP data starts at offset 8 */
  72         printf ("CDP v%d, ttl=%ds", p[i], p[i+1] );
  73         i+=4;           /* skip version, TTL and chksum */
  74
  75         while (i < length) {
  76             if ( i+4 > caplen ) {
  77                 printf("[!cdp]");
  78                 return;
  79             }
  80             type = (p[i]<<8) + p[i+1];
  81             len  = (p[i+2]<<8) + p[i+3];
  82
  83             if ( vflag )
  84                 printf( "\n\t%02x/%02x", type, len );
  85             else
  86                 printf( "\n\t" );
  87
  88             if ( i+len > caplen ) {
  89                 printf("[!cdp]");
  90                 return;
  91             }
  92
  93             switch( type )
  94             {
  95             case 0x01:
  96                 printf( " DevID '%.*s'", len-4, p+i+4 );
  97                 break;
  98             case 0x02:
  99                 printf( " Addr" );
 100                 cdp_print_addr( p+i+4, len-4 );
 101                 break;
 102             case 0x03:
 103                 printf( " PortID '%.*s'", len-4, p+i+4 );
 104                 break;
 105             case 0x04:
 106                 printf( " CAP 0x%02x", (unsigned) p[i+7] );
 107                 break;
 108             case 0x05:
 109                 if ( vflag )
 110                     printf( " Version:\n%.*s", len-4, p+i+4 );
 111                 else
 112                     printf( " Version: (suppressed)" );
 113                 break;
 114             case 0x06:
 115                 printf( " Platform: '%.*s'", len-4, p+i+4 );
 116                 break;
 117             case 0x07:
 118                 cdp_print_prefixes( p+i+4, len-4 );
 119                 break;
 120             case 0x09:          /* guess - not documented */
 121                 printf( " VTP Management Domain: '%.*s'", len-4, p+i+4 );
 122                 break;
 123             case 0x0a:          /* guess - not documented */
 124                 printf( " Native VLAN ID: %d", (p[i+4]<<8) + p[i+4+1] - 1 );
 125                 break;
 126             case 0x0b:          /* guess - not documented */
 127                 printf( " Duplex: %s", p[i+4] ? "full": "half" );
 128                 break;
 129             default:
 130                 printf( " unknown field type %02x, len %d", type, len );
 131             }
 132
 133             /* avoid infinite loop */
 134             if (len == 0)
 135                 break;
 136             i+=len;
 137         }
 138 }
 139
 140 static void
 141 cdp_print_addr( const u_char * p, int l )
 142 {
 143         int pl, al, num;
 144         const u_char * endp = p+l;
 145
 146         num = (p[0] << 24) + (p[1]<<16) + (p[2]<<8)+ p[3];
 147         p+=4;
 148
 149         printf(" (%d): ", num );
 150
 151         while( p < endp && num >= 0) {
 152                 pl=*(p+1);
 153                 p+=2;
 154
 155                 /* special case: IPv4, protocol type=0xcc, addr. length=4 */
 156                 if ( pl == 1 && *p == 0xcc &&
 157                      p[1] == 0 && p[2] == 4 ) {
 158                         p+=3;
 159
 160                         printf( "IPv4 %d.%d.%d.%d ", p[0], p[1], p[2], p[3] );
 161                         p+=4;
 162                 } else {        /* generic case: just print raw data */
 163                         printf("pt=0x%02x, pl=%d, pb=", *(p-2), pl);
 164                         while( pl-- > 0 )
 165                                 printf( " %02x", *p++);
 166                         al=(*p << 8) + *(p+1);
 167                         printf( ", al=%d, a=", al );
 168                         p+=2;
 169                         while( al-- > 0 )
 170                                 printf( " %02x", *p++);
 171                 }
 172                 printf("  ");
 173                 num--;
 174         }
 175 }
 176
 177
 178 static void
 179 cdp_print_prefixes( const u_char * p, int l )
 180 {
 181     printf( " IPv4 Prefixes (%d):", l/5 );
 182
 183     while(l > 0) {
 184         printf( " %d.%d.%d.%d/%d", p[0], p[1], p[2], p[3], p[4] );
 185         l-=5; p+=5;
 186     }
 187 }