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 1.17 1999/11/16 11:42:28 guy 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 int proto_cdp = -1;
  44 static int hf_cdp_version = -1;
  45 static int hf_cdp_flags = -1;
  46 static int hf_cdp_ttl = -1;
  47 static int hf_cdp_tlvtype = -1;
  48 static int hf_cdp_tlvlength = -1;
  49
  50 static gint ett_cdp = -1;
  51 static gint ett_cdp_tlv = -1;
  52
  53 static void
  54 add_multi_line_string_to_tree(proto_tree *tree, gint start, gint len,
  55   const gchar *prefix, const gchar *string);
  56
  57 #define TYPE_MGMT_ADDR          0
  58 #define TYPE_CHASSIS_ID         1
  59 #define TYPE_2                  2
  60 #define TYPE_PORT               3
  61 #define TYPE_IOS_VERSION        5
  62 #define TYPE_PLATFORM           6
  63 #define TYPE_MGMT_IP_ADDR       0x01cc
  64
  65 static const value_string type_vals[] = {
  66         { TYPE_MGMT_ADDR,    "Mgmt addr?" },
  67         { TYPE_CHASSIS_ID,   "Chassis ID" },
  68         { TYPE_2,            "Unknown" },
  69         { TYPE_PORT,         "Port" },
  70         { TYPE_IOS_VERSION,  "Software version" },
  71         { TYPE_PLATFORM,     "Platform" },
  72         { TYPE_MGMT_IP_ADDR, "Mgmt IP" },
  73         { 0,                 NULL },
  74 };
  75
  76 void
  77 dissect_cdp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
  78     proto_item *ti;
  79     proto_tree *cdp_tree = NULL;
  80     guint16 type;
  81     guint16 length;
  82     char *type_str;
  83     char *stringmem;
  84     proto_item *tlvi;
  85     proto_tree *tlv_tree;
  86
  87     if (check_col(fd, COL_PROTOCOL))
  88         col_add_str(fd, COL_PROTOCOL, "CDP");
  89     if (check_col(fd, COL_INFO))
  90         col_add_str(fd, COL_INFO, "Cisco Discovery Protocol");
  91
  92     if(tree){
  93         ti = proto_tree_add_item(tree, proto_cdp, offset, END_OF_FRAME, NULL);
  94         cdp_tree = proto_item_add_subtree(ti, ett_cdp);
  95
  96         /* CDP header */
  97         proto_tree_add_item(cdp_tree, hf_cdp_version, offset, 1, pd[offset]);
  98         offset += 1;
  99         proto_tree_add_item_format(cdp_tree, hf_cdp_flags, offset, 1,
 100                                    pd[offset],
 101                                    "Flags: %x (unknown)", pd[offset]);
 102         offset += 1;
 103         proto_tree_add_item_format(cdp_tree, hf_cdp_ttl, offset, 2,
 104                                    pntohs(&pd[offset]),
 105                                    "TTL: %u (unknown)", pntohs(&pd[offset]));
 106         offset += 2;
 107
 108         while( IS_DATA_IN_FRAME(offset) ){
 109                 type = pntohs(&pd[offset + TLV_TYPE]);
 110                 length = pntohs(&pd[offset + TLV_LENGTH]);
 111                 type_str = val_to_str(type, type_vals,
 112                     "Unknown (0x%04x)");
 113
 114                 switch( type ){
 115                         case TYPE_MGMT_ADDR:
 116                                 /* ??? Mgmt Addr; in this one, the "length"
 117                                    field doesn't include the length of the
 118                                    type and length fields. */
 119                                 tlvi = proto_tree_add_text(cdp_tree, offset,
 120                                     length + 4, "Type: %s, length: %u",
 121                                     type_str, length);
 122                                 tlv_tree = proto_item_add_subtree(tlvi,
 123                                     ett_cdp_tlv);
 124                                 proto_tree_add_item(tlv_tree, hf_cdp_tlvtype,
 125                                     offset + TLV_TYPE, 2, type);
 126                                 proto_tree_add_item(tlv_tree, hf_cdp_tlvlength,
 127                                     offset + TLV_LENGTH, 2, length);
 128                                 if (length > 0) {
 129                                         proto_tree_add_text(tlv_tree,
 130                                             offset + 4, length, "Data");
 131                                 }
 132                                 offset+=length + 4;
 133                                 break;
 134                         case TYPE_CHASSIS_ID:
 135                                 /* ??? Chassis ID */
 136                                 tlvi = proto_tree_add_text(cdp_tree, offset,
 137                                     length, "Chassis ID: %s",
 138                                     &pd[offset+4]);
 139                                 tlv_tree = proto_item_add_subtree(tlvi,
 140                                     ett_cdp_tlv);
 141                                 proto_tree_add_item(tlv_tree, hf_cdp_tlvtype,
 142                                     offset + TLV_TYPE, 2, type);
 143                                 proto_tree_add_item(tlv_tree, hf_cdp_tlvlength,
 144                                     offset + TLV_LENGTH, 2, length);
 145                                 proto_tree_add_text(tlv_tree, offset + 4,
 146                                     length - 4, "Chassis ID: %s",
 147                                     &pd[offset+4]);
 148                                 offset+=length;
 149                                 break;
 150                         case TYPE_2:
 151                                 /* this is quite strange: this tlv contains
 152                                    no data itself but two tlvs which
 153                                    calculate the length without the 2 byte
 154                                    type and 2 byte length field */
 155                                 tlvi = proto_tree_add_text(cdp_tree, offset,
 156                                     4, "Type: %u (unknown), second field: %u",
 157                                     type, length);
 158                                 tlv_tree = proto_item_add_subtree(tlvi,
 159                                     ett_cdp_tlv);
 160                                 proto_tree_add_item(tlv_tree, hf_cdp_tlvtype,
 161                                     offset + TLV_TYPE, 2, type);
 162                                 proto_tree_add_text(tlv_tree,
 163                                     offset + TLV_LENGTH, 2, "Second field: %u",
 164                                     length);
 165                                 offset+=4;
 166                                 break;
 167                         case TYPE_PORT:
 168                                 /* ??? Port  */
 169                                 tlvi = proto_tree_add_text(cdp_tree, offset,
 170                                     length, "Sent through Interface: %s",
 171                                     &pd[offset+4]);
 172                                 tlv_tree = proto_item_add_subtree(tlvi,
 173                                     ett_cdp_tlv);
 174                                 proto_tree_add_item(tlv_tree, hf_cdp_tlvtype,
 175                                     offset + TLV_TYPE, 2, type);
 176                                 proto_tree_add_item(tlv_tree, hf_cdp_tlvlength,
 177                                     offset + TLV_LENGTH, 2, length);
 178                                 proto_tree_add_text(tlv_tree, offset + 4,
 179                                     length - 4, "Sent through Interface: %s",
 180                                     &pd[offset+4]);
 181                                 offset+=length;
 182                                 break;
 183                         case TYPE_IOS_VERSION:
 184                                 /* ??? IOS Version */
 185                                 add_multi_line_string_to_tree(cdp_tree,
 186                                     offset + 4, length - 4, "Software Version: ",
 187                                     &pd[offset+4] );
 188                                 offset+=length;
 189                                 break;
 190                         case TYPE_PLATFORM:
 191                                 /* ??? platform */
 192                                 stringmem = malloc(length);
 193                                 memset(stringmem, '\0', length);
 194                                 memcpy(stringmem, &pd[offset+4], length - 4 );
 195                                 tlvi = proto_tree_add_text(cdp_tree,
 196                                     offset, length, "Platform: %s",
 197                                     stringmem);
 198                                 tlv_tree = proto_item_add_subtree(tlvi,
 199                                     ett_cdp_tlv);
 200                                 proto_tree_add_item(tlv_tree, hf_cdp_tlvtype,
 201                                     offset + TLV_TYPE, 2, type);
 202                                 proto_tree_add_item(tlv_tree, hf_cdp_tlvlength,
 203                                     offset + TLV_LENGTH, 2, length);
 204                                 proto_tree_add_text(tlv_tree, offset + 4,
 205                                     length - 4, "Platform: %s", stringmem);
 206                                 free(stringmem);
 207                                 offset+=length;
 208                                 break;
 209                         case TYPE_MGMT_IP_ADDR:
 210                                 /* ??? Mgmt IP Addr; in this one, the "length"
 211                                    field doesn't include the length of the
 212                                    type and length fields. */
 213                                 tlvi = proto_tree_add_text(cdp_tree,
 214                                     offset, length + 4, "Mgmt IP: %s",
 215                                     ip_to_str(&pd[offset+4]));
 216                                 tlv_tree = proto_item_add_subtree(tlvi,
 217                                     ett_cdp_tlv);
 218                                 proto_tree_add_item(tlv_tree, hf_cdp_tlvtype,
 219                                     offset + TLV_TYPE, 2, type);
 220                                 proto_tree_add_item(tlv_tree, hf_cdp_tlvlength,
 221                                     offset + TLV_LENGTH, 2, length);
 222                                 proto_tree_add_text(tlv_tree, offset + 4,
 223                                     length, "IP address: %s",
 224                                     ip_to_str(&pd[offset+4]));
 225                                 offset+=length + 4;
 226                                 break;
 227                         default:
 228                                 tlvi = proto_tree_add_text(cdp_tree, offset,
 229                                     length, "Type: %s, length: %u",
 230                                     type_str, length);
 231                                 tlv_tree = proto_item_add_subtree(tlvi,
 232                                     ett_cdp_tlv);
 233                                 proto_tree_add_item(tlv_tree, hf_cdp_tlvtype,
 234                                     offset + TLV_TYPE, 2, type);
 235                                 proto_tree_add_item(tlv_tree, hf_cdp_tlvlength,
 236                                     offset + TLV_LENGTH, 2, length);
 237                                 if (length > 4) {
 238                                         proto_tree_add_text(tlv_tree,
 239                                             offset + 4, length - 4, "Data");
 240                                 } else
 241                                         return;
 242                                 offset+=length;
 243                 }
 244         }
 245         dissect_data(pd, offset, fd, cdp_tree);
 246     }
 247 }
 248
 249 static void
 250 add_multi_line_string_to_tree(proto_tree *tree, gint start, gint len,
 251   const gchar *prefix, const gchar *string)
 252 {
 253     int prefix_len;
 254     int i;
 255     char blanks[64+1];
 256     const gchar *p, *q;
 257     int line_len;
 258     int data_len;
 259
 260     prefix_len = strlen(prefix);
 261     if (prefix_len > 64)
 262         prefix_len = 64;
 263     for (i = 0; i < prefix_len; i++)
 264         blanks[i] = ' ';
 265     blanks[i] = '\0';
 266     p = string;
 267     for (;;) {
 268         q = strchr(p, '\n');
 269         if (q != NULL) {
 270             line_len = q - p;
 271             data_len = line_len + 1;
 272         } else {
 273             line_len = strlen(p);
 274             data_len = line_len;
 275         }
 276         proto_tree_add_text(tree, start, data_len, "%s%.*s", prefix,
 277            line_len, p);
 278         if (q == NULL)
 279             break;
 280         p += data_len;
 281         start += data_len;
 282         prefix = blanks;
 283     }
 284 }
 285
 286 void
 287 proto_register_cdp(void)
 288 {
 289         static hf_register_info hf[] = {
 290                 { &hf_cdp_version,
 291                 { "Version",            "cdp.version",  FT_UINT8, BASE_DEC, NULL, 0x0,
 292                         "" }},
 293
 294                 { &hf_cdp_flags,
 295                 { "Flags",              "cdp.flags", FT_UINT8, BASE_HEX, NULL, 0x0,
 296                         "" }},
 297
 298                 { &hf_cdp_ttl,
 299                 { "TTL",                "cdp.ttl", FT_UINT16, BASE_DEC, NULL, 0x0,
 300                         "" }},
 301
 302                 { &hf_cdp_tlvtype,
 303                 { "Type",               "cdp.tlv.type", FT_UINT16, BASE_HEX, VALS(type_vals), 0x0,
 304                         "" }},
 305
 306                 { &hf_cdp_tlvlength,
 307                 { "Length",             "cdp.tlv.len", FT_UINT16, BASE_DEC, NULL, 0x0,
 308                         "" }},
 309         };
 310         static gint *ett[] = {
 311                 &ett_cdp,
 312                 &ett_cdp_tlv,
 313         };
 314
 315         proto_cdp = proto_register_protocol("Cisco Discovery Protocol", "cdp");
 316         proto_register_field_array(proto_cdp, hf, array_length(hf));
 317         proto_register_subtree_array(ett, array_length(ett));
 318 }