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