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  * SPDX-License-Identifier: GPL-2.0-or-later
   9  */
  10
  11 #include "config.h"
  12
  13 #include <epan/packet.h>
  14 #include <epan/cisco_pid.h>
  15
  16 /*
  17  * See
  18  *
  19  * http://www.barnett.sk/software/bbooks/cisco_multicasting_routing/chap04.html
  20  *
  21  * for some information on CGMP.
  22  */
  23 void proto_register_cgmp(void);
  24 void proto_reg_handoff_cgmp(void);
  25
  26 static dissector_handle_t cgmp_handle;
  27
  28 static int proto_cgmp;
  29 static int hf_cgmp_version;
  30 static int hf_cgmp_type;
  31 static int hf_cgmp_reserved;
  32 static int hf_cgmp_count;
  33 static int hf_cgmp_gda;
  34 static int hf_cgmp_usa;
  35
  36 static int ett_cgmp;
  37
  38 static const value_string type_vals[] = {
  39         { 0, "Join" },
  40         { 1, "Leave" },
  41         { 0, NULL },
  42 };
  43
  44 static int
  45 dissect_cgmp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  46 {
  47         proto_item *ti;
  48         proto_tree *cgmp_tree = NULL;
  49         int offset = 0;
  50         uint8_t count;
  51
  52         col_set_str(pinfo->cinfo, COL_PROTOCOL, "CGMP");
  53         col_set_str(pinfo->cinfo, COL_INFO, "Cisco Group Management Protocol");
  54
  55         if (tree) {
  56                 ti = proto_tree_add_item(tree, proto_cgmp, tvb, offset, -1,
  57                     ENC_NA);
  58                 cgmp_tree = proto_item_add_subtree(ti, ett_cgmp);
  59
  60                 proto_tree_add_item(cgmp_tree, hf_cgmp_version, tvb, offset, 1,
  61                     ENC_BIG_ENDIAN);
  62                 proto_tree_add_item(cgmp_tree, hf_cgmp_type, tvb, offset, 1,
  63                     ENC_BIG_ENDIAN);
  64                 offset += 1;
  65
  66                 proto_tree_add_item(cgmp_tree, hf_cgmp_reserved, tvb, offset, 2,
  67                     ENC_BIG_ENDIAN);
  68                 offset += 2;
  69
  70                 count = tvb_get_uint8(tvb, offset);
  71                 proto_tree_add_uint(cgmp_tree, hf_cgmp_count, tvb, offset, 1,
  72                     count);
  73                 offset += 1;
  74
  75                 while (count != 0) {
  76                         proto_tree_add_item(cgmp_tree, hf_cgmp_gda, tvb, offset, 6,
  77                             ENC_NA);
  78                         offset += 6;
  79
  80                         proto_tree_add_item(cgmp_tree, hf_cgmp_usa, tvb, offset, 6,
  81                             ENC_NA);
  82                         offset += 6;
  83
  84                         count--;
  85                 }
  86         }
  87         return tvb_captured_length(tvb);
  88 }
  89
  90 void
  91 proto_register_cgmp(void)
  92 {
  93         static hf_register_info hf[] = {
  94                 { &hf_cgmp_version,
  95                 { "Version",    "cgmp.version", FT_UINT8, BASE_DEC, NULL, 0xF0,
  96                         NULL, HFILL }},
  97
  98                 { &hf_cgmp_type,
  99                 { "Type",       "cgmp.type",    FT_UINT8, BASE_DEC, VALS(type_vals), 0x0F,
 100                         NULL, HFILL }},
 101
 102                 { &hf_cgmp_reserved,
 103                 { "Reserved",   "cgmp.reserved", FT_UINT16, BASE_HEX, NULL, 0x0,
 104                         NULL, HFILL }},
 105
 106                 { &hf_cgmp_count,
 107                 { "Count",      "cgmp.count", FT_UINT8, BASE_DEC, NULL, 0x0,
 108                         NULL, HFILL }},
 109
 110                 { &hf_cgmp_gda,
 111                 { "Group Destination Address",  "cgmp.gda", FT_ETHER, BASE_NONE, NULL, 0x0,
 112                         NULL, HFILL }},
 113
 114                 { &hf_cgmp_usa,
 115                 { "Unicast Source Address",     "cgmp.usa", FT_ETHER, BASE_NONE, NULL, 0x0,
 116                         NULL, HFILL }},
 117         };
 118         static int *ett[] = {
 119                 &ett_cgmp,
 120         };
 121
 122         proto_cgmp = proto_register_protocol("Cisco Group Management Protocol",
 123             "CGMP", "cgmp");
 124         proto_register_field_array(proto_cgmp, hf, array_length(hf));
 125         proto_register_subtree_array(ett, array_length(ett));
 126
 127         cgmp_handle = register_dissector("cgmp", dissect_cgmp, proto_cgmp);
 128 }
 129
 130 void
 131 proto_reg_handoff_cgmp(void)
 132 {
 133         dissector_add_uint("llc.cisco_pid", CISCO_PID_CGMP, cgmp_handle);
 134         dissector_add_uint("ethertype", 0x2001, cgmp_handle);
 135 }
 136
 137 /*
 138  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 139  *
 140  * Local variables:
 141  * c-basic-offset: 8
 142  * tab-width: 8
 143  * indent-tabs-mode: t
 144  * End:
 145  *
 146  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 147  * :indentSize=8:tabSize=8:noTabs=false:
 148  */