epan/dissectors/packet-cgmp.c

   1 /* packet-cgmp.c
   2  * Routines for the disassembly of the Cisco Group Management Protocol
   3  *
   4  * $Id$
   5  *
   6  * Wireshark - Network traffic analyzer
   7  * By Gerald Combs <gerald@wireshark.org>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * as published by the Free Software Foundation; either version 2
  13  * of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  23  */
  24
  25 #include "config.h"
  26
  27 #include <stdlib.h>
  28
  29 #include <glib.h>
  30 #include <epan/packet.h>
  31
  32 /*
  33  * See
  34  *
  35  * http://www.barnett.sk/software/bbooks/cisco_multicasting_routing/chap04.html
  36  *
  37  * for some information on CGMP.
  38  */
  39
  40 static int proto_cgmp = -1;
  41 static int hf_cgmp_version = -1;
  42 static int hf_cgmp_type = -1;
  43 static int hf_cgmp_count = -1;
  44 static int hf_cgmp_gda = -1;
  45 static int hf_cgmp_usa = -1;
  46
  47 static gint ett_cgmp = -1;
  48
  49 static const value_string type_vals[] = {
  50         { 0, "Join" },
  51         { 1, "Leave" },
  52         { 0, NULL },
  53 };
  54
  55 static void
  56 dissect_cgmp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  57 {
  58         proto_item *ti;
  59         proto_tree *cgmp_tree = NULL;
  60         int offset = 0;
  61         guint8 count;
  62
  63         col_set_str(pinfo->cinfo, COL_PROTOCOL, "CGMP");
  64         col_set_str(pinfo->cinfo, COL_INFO, "Cisco Group Management Protocol");
  65
  66         if (tree) {
  67                 ti = proto_tree_add_item(tree, proto_cgmp, tvb, offset, -1,
  68                     FALSE);
  69                 cgmp_tree = proto_item_add_subtree(ti, ett_cgmp);
  70
  71                 proto_tree_add_item(cgmp_tree, hf_cgmp_version, tvb, offset, 1,
  72                     FALSE);
  73                 proto_tree_add_item(cgmp_tree, hf_cgmp_type, tvb, offset, 1,
  74                     FALSE);
  75                 offset += 1;
  76
  77                 offset += 2;    /* skip reserved field */
  78
  79                 count = tvb_get_guint8(tvb, offset);
  80                 proto_tree_add_uint(cgmp_tree, hf_cgmp_count, tvb, offset, 1,
  81                     count);
  82                 offset += 1;
  83
  84                 while (count != 0) {
  85                         proto_tree_add_item(cgmp_tree, hf_cgmp_gda, tvb, offset, 6,
  86                             FALSE);
  87                         offset += 6;
  88
  89                         proto_tree_add_item(cgmp_tree, hf_cgmp_usa, tvb, offset, 6,
  90                             FALSE);
  91                         offset += 6;
  92
  93                         count--;
  94                 }
  95         }
  96 }
  97
  98 void
  99 proto_register_cgmp(void)
 100 {
 101         static hf_register_info hf[] = {
 102                 { &hf_cgmp_version,
 103                 { "Version",    "cgmp.version", FT_UINT8, BASE_DEC, NULL, 0xF0,
 104                         NULL, HFILL }},
 105
 106                 { &hf_cgmp_type,
 107                 { "Type",       "cgmp.type",    FT_UINT8, BASE_DEC, VALS(type_vals), 0x0F,
 108                         NULL, HFILL }},
 109
 110                 { &hf_cgmp_count,
 111                 { "Count",      "cgmp.count", FT_UINT8, BASE_DEC, NULL, 0x0,
 112                         NULL, HFILL }},
 113
 114                 { &hf_cgmp_gda,
 115                 { "Group Destination Address",  "cgmp.gda", FT_ETHER, BASE_NONE, NULL, 0x0,
 116                         NULL, HFILL }},
 117
 118                 { &hf_cgmp_usa,
 119                 { "Unicast Source Address",     "cgmp.usa", FT_ETHER, BASE_NONE, NULL, 0x0,
 120                         NULL, HFILL }},
 121         };
 122         static gint *ett[] = {
 123                 &ett_cgmp,
 124         };
 125
 126         proto_cgmp = proto_register_protocol("Cisco Group Management Protocol",
 127             "CGMP", "cgmp");
 128         proto_register_field_array(proto_cgmp, hf, array_length(hf));
 129         proto_register_subtree_array(ett, array_length(ett));
 130 }
 131
 132 void
 133 proto_reg_handoff_cgmp(void)
 134 {
 135         dissector_handle_t cgmp_handle;
 136
 137         cgmp_handle = create_dissector_handle(dissect_cgmp, proto_cgmp);
 138         dissector_add("llc.cisco_pid", 0x2001, cgmp_handle);
 139         dissector_add("ethertype", 0x2001, cgmp_handle);
 140 }