packet-gvrp.c

   1 /* packet-gvrp.c
   2  * Routines for GVRP (GARP VLAN Registration Protocol) dissection
   3  * Copyright 2000, Kevin Shi <techishi@ms22.hinet.net>
   4  *
   5  * $Id: packet-gvrp.c,v 1.14 2002/08/28 21:00:14 jmayer Exp $
   6  *
   7  * Ethereal - Network traffic analyzer
   8  * By Gerald Combs <gerald@ethereal.com>
   9  * Copyright 1998 Gerald Combs
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * as published by the Free Software Foundation; either version 2
  14  * of the License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  24  */
  25
  26 #ifdef HAVE_CONFIG_H
  27 # include "config.h"
  28 #endif
  29
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33
  34 #include <glib.h>
  35
  36 #include <epan/packet.h>
  37 #include "llcsaps.h"
  38
  39 /* Initialize the protocol and registered fields */
  40 static int proto_gvrp = -1;
  41 static int hf_gvrp_proto_id = -1;
  42 static int hf_gvrp_attribute_type = -1;
  43 static int hf_gvrp_attribute_length = -1;
  44 static int hf_gvrp_attribute_event = -1;
  45 static int hf_gvrp_attribute_value = -1;
  46 /*static int hf_gvrp_end_of_mark = -1;*/
  47
  48 /* Initialize the subtree pointers */
  49 static gint ett_gvrp = -1;
  50 /*static gint ett_gvrp_message = -1;
  51 static gint ett_gvrp_attribute_list = -1;
  52 static gint ett_gvrp_attribute = -1;*/
  53
  54 static dissector_handle_t data_handle;
  55
  56 /* Constant definitions */
  57 #define GARP_DEFAULT_PROTOCOL_ID        0x0001
  58 #define GARP_END_OF_MARK                0x00
  59
  60 #define GVRP_ATTRIBUTE_TYPE             0x01
  61
  62 static const value_string attribute_type_vals[] = {
  63         { GVRP_ATTRIBUTE_TYPE, "VID" },
  64         { 0,                   NULL }
  65 };
  66
  67 /* The length of GVRP LeaveAll attribute should be 2 octets (one for length
  68  * and the other for event) */
  69 #define GVRP_LENGTH_LEAVEALL            (sizeof(guint8)+sizeof(guint8))
  70
  71 /* The length of GVRP attribute other than LeaveAll should be 4 octets (one
  72  * for length, one for event, and the last two for VID value).
  73  */
  74 #define GVRP_LENGTH_NON_LEAVEALL        (sizeof(guint8)+sizeof(guint8)+sizeof(guint16))
  75
  76 /* Packet offset definitions */
  77 #define GARP_PROTOCOL_ID                0
  78
  79 /* Event definitions */
  80 #define GVRP_EVENT_LEAVEALL             0
  81 #define GVRP_EVENT_JOINEMPTY            1
  82 #define GVRP_EVENT_JOININ               2
  83 #define GVRP_EVENT_LEAVEEMPTY           3
  84 #define GVRP_EVENT_LEAVEIN              4
  85 #define GVRP_EVENT_EMPTY                5
  86
  87 static const value_string event_vals[] = {
  88         { GVRP_EVENT_LEAVEALL,   "Leave All" },
  89         { GVRP_EVENT_JOINEMPTY,  "Join Empty" },
  90         { GVRP_EVENT_JOININ,     "Join In" },
  91         { GVRP_EVENT_LEAVEEMPTY, "Leave Empty" },
  92         { GVRP_EVENT_LEAVEIN,    "Leave In" },
  93         { GVRP_EVENT_EMPTY,      "Empty" },
  94         { 0,                     NULL }
  95 };
  96
  97 /* Code to actually dissect the packets */
  98 static void
  99 dissect_gvrp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 100 {
 101     proto_item   *ti;
 102     proto_tree   *gvrp_tree;
 103     guint16       protocol_id;
 104     guint8        octet;
 105     int           msg_index, attr_index, offset = 0, length = tvb_reported_length(tvb);
 106
 107     if (check_col(pinfo->cinfo, COL_PROTOCOL))
 108         col_set_str(pinfo->cinfo, COL_PROTOCOL, "GVRP");
 109
 110     if (check_col(pinfo->cinfo, COL_INFO))
 111         col_set_str(pinfo->cinfo, COL_INFO, "GVRP");
 112
 113     if (tree)
 114     {
 115         ti = proto_tree_add_item(tree, proto_gvrp, tvb, 0, length, FALSE);
 116
 117         gvrp_tree = proto_item_add_subtree(ti, ett_gvrp);
 118
 119         /* Read in GARP protocol ID */
 120         protocol_id = tvb_get_ntohs(tvb, GARP_PROTOCOL_ID);
 121
 122         proto_tree_add_uint_format(gvrp_tree, hf_gvrp_proto_id, tvb,
 123                                    GARP_PROTOCOL_ID, sizeof(guint16),
 124                                    protocol_id,
 125                                    "Protocol Identifier: 0x%04x (%s)",
 126                                    protocol_id,
 127                                    protocol_id == GARP_DEFAULT_PROTOCOL_ID ?
 128                                      "GARP VLAN Registration Protocol" :
 129                                      "Unknown Protocol");
 130
 131         /* Currently only one protocol ID is supported */
 132         if (protocol_id != GARP_DEFAULT_PROTOCOL_ID)
 133         {
 134             proto_tree_add_text(gvrp_tree, tvb, GARP_PROTOCOL_ID, sizeof(guint16),
 135  "   (Warning: this version of Ethereal only knows about protocol id = 1)");
 136             call_dissector(data_handle,
 137                 tvb_new_subset(tvb, GARP_PROTOCOL_ID + sizeof(guint16), -1, -1),
 138                 pinfo, tree);
 139             return;
 140         }
 141
 142         offset += sizeof(guint16);
 143         length -= sizeof(guint16);
 144
 145         msg_index = 0;
 146
 147         /* Begin to parse GARP messages */
 148         while (length)
 149         {
 150             proto_item   *msg_item;
 151             int           msg_start = offset;
 152
 153             /* Read in attribute type. */
 154             octet = tvb_get_guint8(tvb, offset);
 155
 156             /* Check for end of mark */
 157             if (octet == GARP_END_OF_MARK)
 158             {
 159                 /* End of GARP PDU */
 160                 if (msg_index)
 161                 {
 162                     proto_tree_add_text(gvrp_tree, tvb, offset, sizeof(guint8),
 163                                         "End of mark");
 164                     break;
 165                 }
 166                 else
 167                 {
 168                     call_dissector(data_handle,
 169                         tvb_new_subset(tvb, offset, -1, -1), pinfo, tree);
 170                     return;
 171                 }
 172             }
 173
 174             offset += sizeof(guint8);
 175             length -= sizeof(guint8);
 176
 177             msg_item = proto_tree_add_text(gvrp_tree, tvb, msg_start, -1,
 178                                            "Message %d", msg_index + 1);
 179
 180             proto_tree_add_uint(gvrp_tree, hf_gvrp_attribute_type, tvb,
 181                                 msg_start, sizeof(guint8), octet);
 182
 183             /* GVRP only supports one attribute type. */
 184             if (octet != GVRP_ATTRIBUTE_TYPE)
 185             {
 186                 call_dissector(data_handle, tvb_new_subset(tvb, offset,-1, -1),
 187                     pinfo, tree);
 188                 return;
 189             }
 190
 191             attr_index = 0;
 192
 193             while (length)
 194             {
 195                 int          attr_start = offset;
 196                 proto_item   *attr_item;
 197
 198                 /* Read in attribute length. */
 199                 octet = tvb_get_guint8(tvb, offset);
 200
 201                 /* Check for end of mark */
 202                 if (octet == GARP_END_OF_MARK)
 203                 {
 204                     /* If at least one message has been already read,
 205                      * check for another end of mark.
 206                      */
 207                     if (attr_index)
 208                     {
 209                         proto_tree_add_text(gvrp_tree, tvb, offset,
 210                                             sizeof(guint8), "  End of mark");
 211
 212                         offset += sizeof(guint8);
 213                         length -= sizeof(guint8);
 214
 215                         proto_item_set_len(msg_item, offset - msg_start);
 216                         break;
 217                     }
 218                     else
 219                     {
 220                         call_dissector(data_handle,
 221                             tvb_new_subset(tvb, offset, -1, -1), pinfo, tree);
 222                         return;
 223                     }
 224                 }
 225                 else
 226                 {
 227                     guint8   event;
 228
 229                     offset += sizeof(guint8);
 230                     length -= sizeof(guint8);
 231
 232                     attr_item = proto_tree_add_text(gvrp_tree, tvb,
 233                          attr_start, -1, "  Attribute %d", attr_index + 1);
 234
 235                     proto_tree_add_uint(gvrp_tree, hf_gvrp_attribute_length,
 236                          tvb, attr_start, sizeof(guint8), octet);
 237
 238                     /* Read in attribute event */
 239                     event = tvb_get_guint8(tvb, offset);
 240
 241                     proto_tree_add_uint(gvrp_tree, hf_gvrp_attribute_event,
 242                          tvb, offset, sizeof(guint8), event);
 243
 244                     offset += sizeof(guint8);
 245                     length -= sizeof(guint8);
 246
 247                     switch (event) {
 248
 249                     case GVRP_EVENT_LEAVEALL:
 250                         if (octet != GVRP_LENGTH_LEAVEALL)
 251                         {
 252                             call_dissector(data_handle,
 253                                 tvb_new_subset(tvb, offset, -1, -1), pinfo,
 254                                 tree);
 255                             return;
 256                         }
 257                         break;
 258
 259                      case GVRP_EVENT_JOINEMPTY:
 260                      case GVRP_EVENT_JOININ:
 261                      case GVRP_EVENT_LEAVEEMPTY:
 262                      case GVRP_EVENT_LEAVEIN:
 263                      case GVRP_EVENT_EMPTY:
 264                         if (octet != GVRP_LENGTH_NON_LEAVEALL)
 265                         {
 266                             call_dissector(data_handle,
 267                                 tvb_new_subset(tvb, offset, -1, -1),pinfo,
 268                                 tree);
 269                             return;
 270                         }
 271
 272                         /* Show attribute value */
 273                         proto_tree_add_item(gvrp_tree, hf_gvrp_attribute_value,
 274                             tvb, offset, sizeof(guint16), FALSE);
 275
 276                         offset += sizeof(guint16);
 277                         length -= sizeof(guint16);
 278                         break;
 279
 280                      default:
 281                         call_dissector(data_handle,
 282                             tvb_new_subset(tvb, offset, -1, -1), pinfo, tree);
 283                         return;
 284                     }
 285                 }
 286
 287                 proto_item_set_len(attr_item, offset - attr_start);
 288
 289                 attr_index++;
 290             }
 291
 292             msg_index++;
 293         }
 294     }
 295 }
 296
 297
 298 /* Register the protocol with Ethereal */
 299 void
 300 proto_register_gvrp(void)
 301 {
 302     static hf_register_info hf[] = {
 303         { &hf_gvrp_proto_id,
 304             { "Protocol ID", "garp.protocol_id",
 305             FT_UINT16,      BASE_HEX,      NULL,  0x0,
 306             "", HFILL }
 307         },
 308         { &hf_gvrp_attribute_type,
 309             { "Type",        "garp.attribute_type",
 310             FT_UINT8,        BASE_HEX,      VALS(attribute_type_vals),  0x0,
 311             "", HFILL }
 312         },
 313         { &hf_gvrp_attribute_length,
 314             { "Length",      "garp.attribute_length",
 315             FT_UINT8,        BASE_DEC,      NULL,  0x0,
 316             "", HFILL }
 317         },
 318         { &hf_gvrp_attribute_event,
 319             { "Event",       "garp.attribute_event",
 320             FT_UINT8,        BASE_DEC,      VALS(event_vals),  0x0,
 321             "", HFILL }
 322         },
 323         { &hf_gvrp_attribute_value,
 324             { "Value",       "garp.attribute_value",
 325             FT_UINT16,       BASE_DEC,      NULL,  0x0,
 326             "", HFILL }
 327         }
 328     };
 329
 330     static gint *ett[] = {
 331         &ett_gvrp
 332     };
 333
 334     /* Register the protocol name and description for GVRP */
 335     proto_gvrp = proto_register_protocol("GARP VLAN Registration Protocol",
 336                                          "GVRP", "gvrp");
 337
 338     /* Required function calls to register the header fields and subtrees
 339      * used by GVRP */
 340     proto_register_field_array(proto_gvrp, hf, array_length(hf));
 341     proto_register_subtree_array(ett, array_length(ett));
 342
 343     register_dissector("gvrp", dissect_gvrp, proto_gvrp);
 344 }
 345
 346 void
 347 proto_reg_handoff_gvrp(void){
 348   data_handle = find_dissector("data");
 349 }