epan/dissectors/packet-rgmp.c

   1 /* packet-rgmp.c
   2  * Routines for IGMP/RGMP packet disassembly
   3  * Copyright 2006 Jaap Keuter
   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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  24  */
  25
  26 /*
  27  Based on RFC3488
  28
  29  This is a setup for RGMP dissection, a simple protocol bolted on IGMP.
  30  The trick is to have IGMP dissector call this function (which by itself is not
  31  registered as dissector). IGAP and other do the same.
  32
  33  */
  34
  35 #include "config.h"
  36
  37 #include <glib.h>
  38 #include <epan/packet.h>
  39 #include <epan/strutil.h>
  40 #include "packet-igmp.h"
  41 #include "packet-rgmp.h"
  42
  43
  44 static int proto_rgmp      = -1;
  45 static int hf_type         = -1;
  46 static int hf_checksum     = -1;
  47 static int hf_checksum_bad = -1;
  48 static int hf_maddr        = -1;
  49
  50 static int ett_rgmp = -1;
  51
  52 static const value_string rgmp_types[] = {
  53     {IGMP_RGMP_LEAVE, "Leave"},
  54     {IGMP_RGMP_JOIN,  "Join"},
  55     {IGMP_RGMP_BYE,   "Bye"},
  56     {IGMP_RGMP_HELLO, "Hello"},
  57     {0, NULL}
  58 };
  59
  60 /* This function is only called from the IGMP dissector */
  61 int
  62 dissect_rgmp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, int offset)
  63 {
  64     proto_tree *tree;
  65     proto_item *item;
  66     guint8 type;
  67
  68     if (!proto_is_protocol_enabled(find_protocol_by_id(proto_rgmp))) {
  69         /* we are not enabled, skip entire packet to be nice
  70            to the igmp layer. (so clicking on IGMP will display the data)
  71            */
  72         return offset + tvb_length_remaining(tvb, offset);
  73     }
  74
  75     item = proto_tree_add_item(parent_tree, proto_rgmp, tvb, offset, -1, ENC_NA);
  76     tree = proto_item_add_subtree(item, ett_rgmp);
  77
  78     col_set_str(pinfo->cinfo, COL_PROTOCOL, "RGMP");
  79     col_clear(pinfo->cinfo, COL_INFO);
  80
  81     type = tvb_get_guint8(tvb, offset);
  82         col_add_str(pinfo->cinfo, COL_INFO,
  83                      val_to_str(type, rgmp_types, "Unknown Type: 0x%02x"));
  84     proto_tree_add_uint(tree, hf_type, tvb, offset, 1, type);
  85     offset += 1;
  86
  87     /* reserved */
  88
  89     offset += 1;
  90
  91     igmp_checksum(tree, tvb, hf_checksum, hf_checksum_bad, pinfo, 0);
  92     offset += 2;
  93
  94     proto_tree_add_item(tree, hf_maddr, tvb, offset, 4, ENC_BIG_ENDIAN);
  95     offset += 4;
  96
  97     return offset;
  98 }
  99
 100
 101 void
 102 proto_register_rgmp(void)
 103 {
 104     static hf_register_info hf[] = {
 105         { &hf_type,
 106           { "Type", "rgmp.type", FT_UINT8, BASE_HEX,
 107             VALS(rgmp_types), 0, "RGMP Packet Type", HFILL }
 108         },
 109
 110         { &hf_checksum,
 111           { "Checksum", "rgmp.checksum", FT_UINT16, BASE_HEX,
 112             NULL, 0, NULL, HFILL }
 113         },
 114
 115         { &hf_checksum_bad,
 116           { "Bad Checksum", "rgmp.checksum_bad", FT_BOOLEAN, BASE_NONE,
 117             NULL, 0x0, NULL, HFILL }
 118         },
 119
 120         { &hf_maddr,
 121           { "Multicast group address", "rgmp.maddr", FT_IPv4, BASE_NONE,
 122             NULL, 0, NULL, HFILL }
 123         }
 124     };
 125
 126     static gint *ett[] = {
 127         &ett_rgmp
 128     };
 129
 130     proto_rgmp = proto_register_protocol
 131         ("Router-port Group Management Protocol", "RGMP", "rgmp");
 132     proto_register_field_array(proto_rgmp, hf, array_length(hf));
 133     proto_register_subtree_array(ett, array_length(ett));
 134 }