packet-cdp.c

   1 /* packet-cdp.c
   2  * Routines for the disassembly of the "Cisco Discovery Protocol"
   3  * (c) Copyright Hannes R. Boehm <hannes@boehm.org>
   4  *
   5  * $Id: packet-cdp.c,v 1.8 1999/03/23 03:14:36 gram Exp $
   6  *
   7  * Ethereal - Network traffic analyzer
   8  * By Gerald Combs <gerald@zing.org>
   9  * Copyright 1998 Gerald Combs
  10  *
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  25  */
  26
  27 #include "config.h"
  28
  29 #ifdef HAVE_SYS_TYPES_H
  30 #include <sys/types.h>
  31 #endif
  32
  33 #include <stdlib.h>
  34 #include <string.h>
  35
  36 #include <glib.h>
  37 #include "packet.h"
  38
  39 /* Offsets in TLV structure. */
  40 #define TLV_TYPE        0
  41 #define TLV_LENGTH      2
  42
  43 static void
  44 add_multi_line_string_to_tree(proto_tree *tree, gint start, gint len,
  45   const gchar *prefix, const gchar *string);
  46
  47 void
  48 dissect_cdp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
  49     proto_tree *cdp_tree = NULL;
  50         proto_item *ti;
  51
  52     typedef struct _e_cdp_hdr{
  53                 char version;
  54                 char flags;
  55                 gint16 ttl;
  56         } e_cdp_hdr;
  57
  58     e_cdp_hdr *cdp_hdr;
  59     char *stringmem;
  60     gint16 type;
  61     gint16 length;
  62
  63     if (check_col(fd, COL_PROTOCOL))
  64         col_add_str(fd, COL_PROTOCOL, "CDP");
  65     if (check_col(fd, COL_INFO))
  66         col_add_str(fd, COL_INFO, "Cisco Discovery Protocol");
  67
  68     if(tree){
  69         ti = proto_tree_add_item(tree, offset, (fd->cap_len - offset),
  70                                                           "Cisco Discovery Protocol");
  71         cdp_tree = proto_tree_new();
  72         proto_item_add_subtree(ti, cdp_tree, ETT_CDP);
  73
  74         /* CDP header */
  75         cdp_hdr = (e_cdp_hdr *) &pd[offset];
  76         proto_tree_add_item(cdp_tree, offset, 1, "Version: %d", cdp_hdr->version);
  77         proto_tree_add_item(cdp_tree, offset+1, 1, "Flags (unknown)");
  78         proto_tree_add_item(cdp_tree, offset+2, 2, "TTL (unknown)");
  79         offset+=4;
  80
  81         /* CVS -> exit here
  82         dissect_data(pd, offset, fd, cdp_tree);
  83                 return;
  84      */
  85
  86         while( offset <= fd->cap_len ){
  87                 type = pntohs(&pd[offset + TLV_TYPE]);
  88                 length = pntohs(&pd[offset + TLV_LENGTH]);
  89                 switch( type ){
  90                         case 0: /* ??? Mgmt Addr */
  91                                 offset+=length + 4;
  92                                 break;
  93                         case 1: /* ??? Chassis ID */
  94                                 proto_tree_add_item(cdp_tree, offset + 4,
  95                                     length - 4, "Chassis ID: %s", &pd[offset+4] );
  96                                 offset+=length;
  97                                 break;
  98                         case 2:
  99                                 /* this is quite strange: this tlv contains no data itself but two tlvs which
 100                  * calculate the length without the 2 byte type and 2 byte length field
 101                  */
 102                                 offset+=4;
 103                                 break;
 104                         case 3: /* ??? Port  */
 105                                 proto_tree_add_item(cdp_tree, offset + 4,
 106                                   length - 4, "Sent through Interface: %s", &pd[offset+4] );
 107                                 offset+=length;
 108                                 break;
 109                         case 5: /* ??? IOS Version */
 110                                 add_multi_line_string_to_tree(cdp_tree,
 111                                     offset + 4, length - 4, "Software Version: ",
 112                                     &pd[offset+4] );
 113                                 offset+=length;
 114                                 break;
 115                         case 6: /* ??? platform */
 116
 117                                 stringmem = malloc(length);
 118                                 memset(stringmem, '\0', length);
 119                                 memcpy(stringmem, &pd[offset+4], length - 4 );
 120                                 proto_tree_add_item(cdp_tree, offset + 4, length - 4,
 121                                                      "Platform: %s", stringmem );
 122                                 free(stringmem);
 123                                 offset+=length;
 124                                 break;
 125                         case 0x01cc: /* ??? Mgmt Addr */
 126                                 proto_tree_add_item(cdp_tree, offset + 4, length,
 127                                                      "Mgmt IP: %s",
 128                                                      ip_to_str(&pd[offset+4]) );
 129                                 offset+=length + 4;
 130                                 break;
 131                         default:
 132 /*
 133                                 if( type > 512){
 134                                         dissect_data(pd, offset, fd, cdp_tree);
 135                                         return;
 136                                 }
 137 */
 138 /*
 139                                 proto_tree_add_item(cdp_tree, offset + TLV_TYPE,
 140                                     2, "Type: %d", type);
 141                                 proto_tree_add_item(cdp_tree, offset + TLV_LENGTH,
 142                                     2, "Length: %d", length);
 143                                 proto_tree_add_item(cdp_tree, offset + 4,
 144                                     length - 4, "Data");
 145 */
 146
 147                                 offset+=length;
 148                 }
 149
 150         }
 151         dissect_data(pd, offset, fd, cdp_tree);
 152     }
 153 }
 154
 155 static void
 156 add_multi_line_string_to_tree(proto_tree *tree, gint start, gint len,
 157   const gchar *prefix, const gchar *string)
 158 {
 159     int prefix_len;
 160     int i;
 161     char blanks[64+1];
 162     const gchar *p, *q;
 163     int line_len;
 164     int data_len;
 165
 166     prefix_len = strlen(prefix);
 167     if (prefix_len > 64)
 168         prefix_len = 64;
 169     for (i = 0; i < prefix_len; i++)
 170         blanks[i] = ' ';
 171     blanks[i] = '\0';
 172     p = string;
 173     for (;;) {
 174         q = strchr(p, '\n');
 175         if (q != NULL) {
 176             line_len = q - p;
 177             data_len = line_len + 1;
 178         } else {
 179             line_len = strlen(p);
 180             data_len = line_len;
 181         }
 182         proto_tree_add_item(tree, start, data_len, "%s%.*s", prefix,
 183            line_len, p);
 184         if (q == NULL)
 185             break;
 186         p += data_len;
 187         start += data_len;
 188         prefix = blanks;
 189     }
 190 }