epan/dissectors/packet-tte.c

   1 /* packet-tte.c
   2  * Routines for Time Triggered Ethernet dissection
   3  *
   4  * Author: Valentin Ecker, valentin.ecker (AT) tttech.com
   5  * Author: Benjamin Roch, benjamin.roch (AT) tttech.com
   6  *
   7  * TTTech Computertechnik AG, Austria.
   8  * http://www.tttech.com/solutions/ttethernet/
   9  *
  10  * $Id$
  11  *
  12  * Wireshark - Network traffic analyzer
  13  * By Gerald Combs <gerald@wireshark.org>
  14  * Copyright 1998 Gerald Combs
  15  *
  16  * This program is free software; you can redistribute it and/or
  17  * modify it under the terms of the GNU General Public License
  18  * as published by the Free Software Foundation; either version 2
  19  * of the License, or (at your option) any later version.
  20  *
  21  * This program is distributed in the hope that it will be useful,
  22  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  23  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24  * GNU General Public License for more details.
  25  *
  26  * You should have received a copy of the GNU General Public License
  27  * along with this program; if not, write to the Free Software
  28  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
  29  * USA.
  30  */
  31
  32 #include "config.h"
  33
  34 #include <glib.h>
  35
  36 #include <epan/packet.h>
  37 #include <epan/prefs.h>
  38 #include <epan/etypes.h>
  39
  40 #include "packet-tte.h"
  41
  42 /* Initialize the protocol and registered fields */
  43 static int proto_tte = -1;
  44
  45 static int hf_eth_dst       = -1;
  46 static int hf_tte_dst_cf    = -1;
  47 static int hf_tte_ctid      = -1;
  48 static int hf_eth_src       = -1;
  49 static int hf_eth_type      = -1;
  50
  51 /* preference value pointers */
  52 static guint32    tte_pref_ct_marker    = 0xFFFFFFFF;
  53 static guint32    tte_pref_ct_mask      = 0x0;
  54
  55 /* Initialize the subtree pointers */
  56 static gint ett_tte = -1;
  57 static gint ett_tte_macdest = -1;
  58
  59
  60 /* Code to actually dissect the packets */
  61 static int
  62 dissect_tte(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
  63 {
  64     int is_frame_pcf;
  65
  66     /* Set up structures needed to add the protocol subtree and manage it */
  67     proto_item *tte_root_item, *tte_macdest_item;
  68     proto_tree *tte_tree, *tte_macdest_tree;
  69
  70     /* Check that there's enough data */
  71     if (tvb_length(tvb) < TTE_HEADER_LENGTH)
  72         return 0;
  73
  74     /* check if data of pcf frame */
  75     is_frame_pcf =
  76        (tvb_get_ntohs(tvb, TTE_MAC_LENGTH * 2) == ETHERTYPE_TTE_PCF);
  77
  78     /* return if no valid constant field is found */
  79     if (!is_frame_pcf)
  80     {
  81         if ( (tvb_get_ntohl(tvb, 0) & tte_pref_ct_mask) != tte_pref_ct_marker)
  82             return 0;
  83     }
  84
  85     /* Make entries in Protocol column and Info column on summary display */
  86     col_set_str(pinfo->cinfo, COL_PROTOCOL, "TTE ");
  87
  88     col_set_str(pinfo->cinfo, COL_INFO, "Bogus TTEthernet Frame");
  89
  90     if (tree) {
  91
  92         /* create display subtree for the protocol */
  93         tte_root_item = proto_tree_add_item(tree, proto_tte, tvb, 0,
  94             TTE_HEADER_LENGTH, ENC_NA);
  95
  96         tte_tree = proto_item_add_subtree(tte_root_item, ett_tte);
  97
  98         tte_macdest_item = proto_tree_add_item(tte_tree,
  99             hf_eth_dst, tvb, 0, TTE_MAC_LENGTH, ENC_NA);
 100
 101         proto_tree_add_item(tte_tree,
 102             hf_eth_src, tvb, TTE_MAC_LENGTH, TTE_MAC_LENGTH, ENC_NA);
 103
 104         proto_tree_add_item(tte_tree,
 105             hf_eth_type, tvb, TTE_MAC_LENGTH*2, TTE_ETHERTYPE_LENGTH,
 106             ENC_BIG_ENDIAN);
 107
 108         tte_macdest_tree = proto_item_add_subtree(tte_macdest_item,
 109             ett_tte_macdest);
 110
 111         proto_tree_add_item(tte_macdest_tree,
 112             hf_tte_dst_cf, tvb, 0, TTE_MACDEST_CF_LENGTH, ENC_BIG_ENDIAN);
 113
 114         proto_tree_add_item(tte_macdest_tree,
 115             hf_tte_ctid, tvb, TTE_MACDEST_CF_LENGTH,
 116             TTE_MACDEST_CTID_LENGTH, ENC_BIG_ENDIAN);
 117     }
 118
 119     /* prevent clearing the Columns...appending cannot be prevented */
 120     col_set_fence(pinfo->cinfo, COL_PROTOCOL);
 121
 122     /* call std Ethernet dissector */
 123     ethertype (tvb_get_ntohs(tvb, TTE_MAC_LENGTH * 2), tvb
 124         , 14, pinfo, tree, NULL, hf_eth_type, 0, 0 );
 125
 126     return tvb_length(tvb);
 127 }
 128
 129
 130 void
 131 proto_register_tte(void)
 132 {
 133     module_t *tte_module;
 134
 135     static hf_register_info hf[] = {
 136         { &hf_tte_dst_cf,
 137           { "Constant Field",   "tte.cf",
 138             FT_UINT32, BASE_HEX, NULL, 0x0,
 139             NULL, HFILL }
 140         },
 141         { &hf_tte_ctid,
 142           { "Critical Traffic Identifier", "tte.ctid",
 143             FT_UINT16, BASE_HEX, NULL, 0x0,
 144             NULL, HFILL }
 145         }
 146     };
 147
 148     /* Setup protocol subtree array */
 149     static gint *ett[] = {
 150         &ett_tte,
 151         &ett_tte_macdest
 152     };
 153
 154     /* Register the protocol name and description */
 155     proto_tte = proto_register_protocol("TTEthernet", "TTE", "tte");
 156
 157     /* Required function calls to register header fields and subtrees used */
 158     proto_register_field_array(proto_tte, hf, array_length(hf));
 159     proto_register_subtree_array(ett, array_length(ett));
 160
 161     /* Register preferences module */
 162     tte_module = prefs_register_protocol(proto_tte, NULL);
 163
 164     /* Register preferences */
 165     prefs_register_uint_preference(tte_module, "ct_mask_value",
 166         "CT Mask (in hex)",
 167         "Critical Traffic Mask (base hex)",
 168         16, &tte_pref_ct_mask);
 169
 170     prefs_register_uint_preference(tte_module, "ct_marker_value",
 171         "CT Marker (in hex)",
 172         "Critical Traffic Marker (base hex)",
 173         16, &tte_pref_ct_marker);
 174 }
 175
 176
 177 void
 178 proto_reg_handoff_tte(void)
 179 {
 180     heur_dissector_add("eth", dissect_tte, proto_tte);
 181
 182     hf_eth_dst  = proto_registrar_get_id_byname ("eth.dst");
 183     hf_eth_src  = proto_registrar_get_id_byname ("eth.src");
 184     hf_eth_type = proto_registrar_get_id_byname ("eth.type");
 185 }