packet-cgmp.c

   1 /* packet-cgmp.c
   2  * Routines for the disassembly of the Cisco Group Management Protocol
   3  *
   4  * $Id: packet-cgmp.c,v 1.15 2002/03/23 22:02:20 guy Exp $
   5  *
   6  * Ethereal - Network traffic analyzer
   7  * By Gerald Combs <gerald@ethereal.com>
   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 #ifdef HAVE_SYS_TYPES_H
  28 #include <sys/types.h>
  29 #endif
  30
  31 #include <stdlib.h>
  32 #include <string.h>
  33
  34 #include <glib.h>
  35 #include <epan/packet.h>
  36
  37 /*
  38  * See
  39  *
  40  * http://www.barnett.sk/software/bbooks/cisco_multicasting_routing/chap04.html
  41  *
  42  * for some information on CGMP.
  43  */
  44
  45 static int proto_cgmp = -1;
  46 static int hf_cgmp_version = -1;
  47 static int hf_cgmp_type = -1;
  48 static int hf_cgmp_count = -1;
  49 static int hf_cgmp_gda = -1;
  50 static int hf_cgmp_usa = -1;
  51
  52 static gint ett_cgmp = -1;
  53
  54 static const value_string type_vals[] = {
  55         { 0, "Join" },
  56         { 1, "Leave" },
  57         { 0, NULL },
  58 };
  59
  60 static void
  61 dissect_cgmp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  62 {
  63         proto_item *ti;
  64         proto_tree *cgmp_tree = NULL;
  65         int offset = 0;
  66         guint8 count;
  67
  68         if (check_col(pinfo->cinfo, COL_PROTOCOL))
  69                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "CGMP");
  70         if (check_col(pinfo->cinfo, COL_INFO))
  71                 col_set_str(pinfo->cinfo, COL_INFO, "Cisco Group Management Protocol");
  72
  73         if (tree) {
  74                 ti = proto_tree_add_item(tree, proto_cgmp, tvb, offset, -1,
  75                     FALSE);
  76                 cgmp_tree = proto_item_add_subtree(ti, ett_cgmp);
  77
  78                 proto_tree_add_item(cgmp_tree, hf_cgmp_version, tvb, offset, 1,
  79                     FALSE);
  80                 proto_tree_add_item(cgmp_tree, hf_cgmp_type, tvb, offset, 1,
  81                     FALSE);
  82                 offset += 1;
  83
  84                 offset += 2;    /* skip reserved field */
  85
  86                 count = tvb_get_guint8(tvb, offset);
  87                 proto_tree_add_uint(cgmp_tree, hf_cgmp_count, tvb, offset, 1,
  88                     count);
  89                 offset += 1;
  90
  91                 while (count != 0) {
  92                         proto_tree_add_item(cgmp_tree, hf_cgmp_gda, tvb, offset, 6,
  93                             FALSE);
  94                         offset += 6;
  95
  96                         proto_tree_add_item(cgmp_tree, hf_cgmp_usa, tvb, offset, 6,
  97                             FALSE);
  98                         offset += 6;
  99
 100                         count--;
 101                 }
 102         }
 103 }
 104
 105 void
 106 proto_register_cgmp(void)
 107 {
 108         static hf_register_info hf[] = {
 109                 { &hf_cgmp_version,
 110                 { "Version",    "cgmp.version", FT_UINT8, BASE_DEC, NULL, 0xF0,
 111                         "", HFILL }},
 112
 113                 { &hf_cgmp_type,
 114                 { "Type",       "cgmp.type",    FT_UINT8, BASE_DEC, VALS(type_vals), 0x0F,
 115                         "", HFILL }},
 116
 117                 { &hf_cgmp_count,
 118                 { "Count",      "cgmp.count", FT_UINT8, BASE_DEC, NULL, 0x0,
 119                         "", HFILL }},
 120
 121                 { &hf_cgmp_gda,
 122                 { "Group Destination Address",  "cgmp.gda", FT_ETHER, BASE_NONE, NULL, 0x0,
 123                         "Group Destination Address", HFILL }},
 124
 125                 { &hf_cgmp_usa,
 126                 { "Unicast Source Address",     "cgmp.usa", FT_ETHER, BASE_NONE, NULL, 0x0,
 127                         "Unicast Source Address", HFILL }},
 128         };
 129         static gint *ett[] = {
 130                 &ett_cgmp,
 131         };
 132
 133         proto_cgmp = proto_register_protocol("Cisco Group Management Protocol",
 134             "CGMP", "cgmp");
 135         proto_register_field_array(proto_cgmp, hf, array_length(hf));
 136         proto_register_subtree_array(ett, array_length(ett));
 137 }
 138
 139 void
 140 proto_reg_handoff_cgmp(void)
 141 {
 142         dissector_handle_t cgmp_handle;
 143
 144         cgmp_handle = create_dissector_handle(dissect_cgmp, proto_cgmp);
 145         dissector_add("llc.cisco_pid", 0x2001, cgmp_handle);
 146         dissector_add("ethertype", 0x2001, cgmp_handle);
 147 }