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  * https://www.tttech.com/technologies/time-triggered-ethernet/
   9  *
  10  * Wireshark - Network traffic analyzer
  11  * By Gerald Combs <gerald@wireshark.org>
  12  * Copyright 1998 Gerald Combs
  13  *
  14  * SPDX-License-Identifier: GPL-2.0-or-later
  15  */
  16
  17 #include "config.h"
  18
  19 #include <epan/packet.h>
  20 #include <epan/prefs.h>
  21 #include <epan/etypes.h>
  22
  23 #include "packet-tte.h"
  24
  25 void proto_register_tte(void);
  26 void proto_reg_handoff_tte(void);
  27
  28 static dissector_handle_t ethertype_handle;
  29
  30 /* Initialize the protocol and registered fields */
  31 static int proto_tte;
  32
  33 static int hf_eth_dst;
  34 static int hf_tte_dst_cf;
  35 static int hf_tte_ctid;
  36 static int hf_eth_src;
  37 static int hf_eth_type;
  38
  39 /* preference value pointers */
  40 static uint32_t   tte_pref_ct_marker    = 0xFFFFFFFF;
  41 static uint32_t   tte_pref_ct_mask      = 0x0;
  42
  43 /* Initialize the subtree pointers */
  44 static int ett_tte;
  45 static int ett_tte_macdest;
  46
  47
  48 /* Code to actually dissect the packets */
  49 static bool
  50 dissect_tte(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
  51 {
  52     int is_frame_pcf;
  53     ethertype_data_t ethertype_data;
  54
  55     /* Set up structures needed to add the protocol subtree and manage it */
  56     proto_item *tte_root_item, *tte_macdest_item;
  57     proto_tree *tte_tree, *tte_macdest_tree;
  58
  59     /* Check that there's enough data */
  60     if (tvb_reported_length(tvb) < TTE_HEADER_LENGTH)
  61         return false;
  62
  63     /* check if data of pcf frame */
  64     is_frame_pcf =
  65        (tvb_get_ntohs(tvb, TTE_MAC_LENGTH * 2) == ETHERTYPE_TTE_PCF);
  66
  67     /* return if no valid constant field is found */
  68     if (!is_frame_pcf)
  69     {
  70         if ( (tvb_get_ntohl(tvb, 0) & tte_pref_ct_mask) != tte_pref_ct_marker)
  71             return false;
  72     }
  73
  74     /* Make entries in Protocol column and Info column on summary display */
  75     col_set_str(pinfo->cinfo, COL_PROTOCOL, "TTE/");
  76
  77     if (tvb_get_ntohs(tvb, TTE_MAC_LENGTH * 2) <= IEEE_802_3_MAX_LEN)
  78     {
  79         col_set_str(pinfo->cinfo, COL_INFO, "TTEthernet Frame");
  80     }
  81     else
  82     {
  83         col_set_str(pinfo->cinfo, COL_INFO, "Bogus TTEthernet Frame");
  84     }
  85
  86     if (tree) {
  87
  88         /* create display subtree for the protocol */
  89         tte_root_item = proto_tree_add_item(tree, proto_tte, tvb, 0,
  90             TTE_HEADER_LENGTH, ENC_NA);
  91
  92         tte_tree = proto_item_add_subtree(tte_root_item, ett_tte);
  93
  94         tte_macdest_item = proto_tree_add_item(tte_tree,
  95             hf_eth_dst, tvb, 0, TTE_MAC_LENGTH, ENC_NA);
  96
  97         proto_tree_add_item(tte_tree,
  98             hf_eth_src, tvb, TTE_MAC_LENGTH, TTE_MAC_LENGTH, ENC_NA);
  99
 100         proto_tree_add_item(tte_tree,
 101             hf_eth_type, tvb, TTE_MAC_LENGTH*2, TTE_ETHERTYPE_LENGTH,
 102             ENC_BIG_ENDIAN);
 103
 104         tte_macdest_tree = proto_item_add_subtree(tte_macdest_item,
 105             ett_tte_macdest);
 106
 107         proto_tree_add_item(tte_macdest_tree,
 108             hf_tte_dst_cf, tvb, 0, TTE_MACDEST_CF_LENGTH, ENC_BIG_ENDIAN);
 109
 110         proto_tree_add_item(tte_macdest_tree,
 111             hf_tte_ctid, tvb, TTE_MACDEST_CF_LENGTH,
 112             TTE_MACDEST_CTID_LENGTH, ENC_BIG_ENDIAN);
 113     }
 114
 115     /* prevent clearing the Columns...appending cannot be prevented */
 116     col_set_fence(pinfo->cinfo, COL_PROTOCOL);
 117
 118     /* call std Ethernet dissector */
 119     ethertype_data.etype = tvb_get_ntohs(tvb, TTE_MAC_LENGTH * 2);
 120     ethertype_data.payload_offset = TTE_HEADER_LENGTH;
 121     ethertype_data.fh_tree = NULL;
 122     ethertype_data.trailer_id = 0;
 123     ethertype_data.fcs_len = 0;
 124
 125     call_dissector_with_data(ethertype_handle, tvb, pinfo, tree, &ethertype_data);
 126     return true;
 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 int *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, "TTEthernet", "tte_eth", proto_tte, HEURISTIC_ENABLE);
 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
 186     ethertype_handle = find_dissector_add_dependency("ethertype", proto_tte);
 187 }
 188
 189 /*
 190  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 191  *
 192  * Local variables:
 193  * c-basic-offset: 4
 194  * tab-width: 8
 195  * indent-tabs-mode: nil
 196  * End:
 197  *
 198  * vi: set shiftwidth=4 tabstop=8 expandtab:
 199  * :indentSize=4:tabSize=8:noTabs=true:
 200  */