epan/dissectors/packet-cgmp.c

   1 /* packet-cgmp.c
   2  * Routines for the disassembly of the Cisco Group Management Protocol
   3  *
   4  * Wireshark - Network traffic analyzer
   5  * By Gerald Combs <gerald@wireshark.org>
   6  * Copyright 1998 Gerald Combs
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * as published by the Free Software Foundation; either version 2
  11  * of the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22
  23 #include "config.h"
  24
  25 #include <glib.h>
  26
  27 #include <epan/packet.h>
  28
  29 /*
  30  * See
  31  *
  32  * http://www.barnett.sk/software/bbooks/cisco_multicasting_routing/chap04.html
  33  *
  34  * for some information on CGMP.
  35  */
  36 void proto_register_cgmp(void);
  37 void proto_reg_handoff_cgmp(void);
  38
  39 static int proto_cgmp = -1;
  40 static int hf_cgmp_version = -1;
  41 static int hf_cgmp_type = -1;
  42 static int hf_cgmp_count = -1;
  43 static int hf_cgmp_gda = -1;
  44 static int hf_cgmp_usa = -1;
  45
  46 static gint ett_cgmp = -1;
  47
  48 static const value_string type_vals[] = {
  49         { 0, "Join" },
  50         { 1, "Leave" },
  51         { 0, NULL },
  52 };
  53
  54 static void
  55 dissect_cgmp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  56 {
  57         proto_item *ti;
  58         proto_tree *cgmp_tree = NULL;
  59         int offset = 0;
  60         guint8 count;
  61
  62         col_set_str(pinfo->cinfo, COL_PROTOCOL, "CGMP");
  63         col_set_str(pinfo->cinfo, COL_INFO, "Cisco Group Management Protocol");
  64
  65         if (tree) {
  66                 ti = proto_tree_add_item(tree, proto_cgmp, tvb, offset, -1,
  67                     ENC_NA);
  68                 cgmp_tree = proto_item_add_subtree(ti, ett_cgmp);
  69
  70                 proto_tree_add_item(cgmp_tree, hf_cgmp_version, tvb, offset, 1,
  71                     ENC_BIG_ENDIAN);
  72                 proto_tree_add_item(cgmp_tree, hf_cgmp_type, tvb, offset, 1,
  73                     ENC_BIG_ENDIAN);
  74                 offset += 1;
  75
  76                 offset += 2;    /* skip reserved field */
  77
  78                 count = tvb_get_guint8(tvb, offset);
  79                 proto_tree_add_uint(cgmp_tree, hf_cgmp_count, tvb, offset, 1,
  80                     count);
  81                 offset += 1;
  82
  83                 while (count != 0) {
  84                         proto_tree_add_item(cgmp_tree, hf_cgmp_gda, tvb, offset, 6,
  85                             ENC_NA);
  86                         offset += 6;
  87
  88                         proto_tree_add_item(cgmp_tree, hf_cgmp_usa, tvb, offset, 6,
  89                             ENC_NA);
  90                         offset += 6;
  91
  92                         count--;
  93                 }
  94         }
  95 }
  96
  97 void
  98 proto_register_cgmp(void)
  99 {
 100         static hf_register_info hf[] = {
 101                 { &hf_cgmp_version,
 102                 { "Version",    "cgmp.version", FT_UINT8, BASE_DEC, NULL, 0xF0,
 103                         NULL, HFILL }},
 104
 105                 { &hf_cgmp_type,
 106                 { "Type",       "cgmp.type",    FT_UINT8, BASE_DEC, VALS(type_vals), 0x0F,
 107                         NULL, HFILL }},
 108
 109                 { &hf_cgmp_count,
 110                 { "Count",      "cgmp.count", FT_UINT8, BASE_DEC, NULL, 0x0,
 111                         NULL, HFILL }},
 112
 113                 { &hf_cgmp_gda,
 114                 { "Group Destination Address",  "cgmp.gda", FT_ETHER, BASE_NONE, NULL, 0x0,
 115                         NULL, HFILL }},
 116
 117                 { &hf_cgmp_usa,
 118                 { "Unicast Source Address",     "cgmp.usa", FT_ETHER, BASE_NONE, NULL, 0x0,
 119                         NULL, HFILL }},
 120         };
 121         static gint *ett[] = {
 122                 &ett_cgmp,
 123         };
 124
 125         proto_cgmp = proto_register_protocol("Cisco Group Management Protocol",
 126             "CGMP", "cgmp");
 127         proto_register_field_array(proto_cgmp, hf, array_length(hf));
 128         proto_register_subtree_array(ett, array_length(ett));
 129 }
 130
 131 void
 132 proto_reg_handoff_cgmp(void)
 133 {
 134         dissector_handle_t cgmp_handle;
 135
 136         cgmp_handle = create_dissector_handle(dissect_cgmp, proto_cgmp);
 137         dissector_add_uint("llc.cisco_pid", 0x2001, cgmp_handle);
 138         dissector_add_uint("ethertype", 0x2001, cgmp_handle);
 139 }