epan/dissectors/packet-dpauxmon.c

   1 /* packet-dpauxmon.c
   2  * Routines for DisplayPort AUX-Channel monitor dissection
   3  * Copyright 2018, Dirk Eibach, Guntermann & Drunck GmbH <dirk.eibach@gdsys.cc>
   4  *
   5  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998 Gerald Combs
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-or-later
  10  */
  11
  12 #include <config.h>
  13
  14 #include <epan/packet.h>
  15 #include <epan/conversation.h>
  16 #include <epan/proto_data.h>
  17 #include <wiretap/wtap.h>
  18
  19 #include "packet-dpaux.h"
  20
  21 enum {
  22     DPAUXMON_DATA = 0x00,
  23     DPAUXMON_DATA_END = 0x01,
  24     DPAUXMON_EVENT = 0x02,
  25     DPAUXMON_START = 0x03,
  26     DPAUXMON_STOP = 0x04,
  27     DPAUXMON_TS_OVERFLOW = 0x84,
  28 };
  29
  30 void proto_reg_handoff_dpauxmon(void);
  31 void proto_register_dpauxmon(void);
  32
  33 static dissector_handle_t dpaux_handle;
  34 static dissector_handle_t dpauxmon_handle;
  35
  36 /* Initialize the protocol and registered fields */
  37 static int proto_dpauxmon;
  38
  39 static int hf_packet_type;
  40 static int hf_origin;
  41 static int hf_inputs;
  42 static int hf_hpd;
  43 static int hf_in0;
  44 static int hf_in1;
  45 static int hf_in2;
  46
  47 static int * const input_fields[] = {
  48     &hf_hpd,
  49     &hf_in0,
  50     &hf_in1,
  51     &hf_in2,
  52     NULL
  53 };
  54
  55 /* Initialize the subtree pointers */
  56 static int ett_dpauxmon;
  57
  58 static const value_string packet_type_vals[] = {
  59     { DPAUXMON_DATA, "Data" },
  60     { DPAUXMON_EVENT, "Event" },
  61     { DPAUXMON_START, "Start" },
  62     { DPAUXMON_STOP, "Stop" },
  63     { DPAUXMON_TS_OVERFLOW, "Timestamp Overflow" },
  64     { 0, NULL }
  65 };
  66
  67 static const value_string origin_vals[] = {
  68     { 0, "Sink" },
  69     { 1, "Source" },
  70     { 0, NULL }
  71 };
  72
  73 static int
  74 dissect_dpauxmon(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
  75         void *data _U_)
  76 {
  77     proto_item *ti;
  78     proto_tree *dpauxmon_tree;
  79     uint32_t packet_type;
  80
  81     col_set_str(pinfo->cinfo, COL_PROTOCOL, "DPAUXMON");
  82     col_set_str(pinfo->cinfo, COL_RES_DL_DST, "N/A");
  83     col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "Internal");
  84
  85     /* create display subtree for the protocol */
  86     ti = proto_tree_add_item(tree, proto_dpauxmon, tvb, 0, -1, ENC_NA);
  87     dpauxmon_tree = proto_item_add_subtree(ti, ett_dpauxmon);
  88
  89     proto_tree_add_item_ret_uint(dpauxmon_tree, hf_packet_type, tvb, 0, 1, ENC_NA, &packet_type);
  90     col_add_fstr(pinfo->cinfo, COL_INFO, "DisplayPort AUX channel - %s", val_to_str_const(packet_type, packet_type_vals, "Unknown"));
  91
  92     switch (packet_type) {
  93     case DPAUXMON_DATA: {
  94         struct dpaux_info dpaux_info;
  95
  96         dpaux_info.from_source = tvb_get_uint8(tvb, 1);
  97         proto_tree_add_uint(dpauxmon_tree, hf_origin, tvb, 1, 1, dpaux_info.from_source);
  98
  99         call_dissector_with_data(dpaux_handle, tvb_new_subset_remaining(tvb, 2),
 100                  pinfo, dpauxmon_tree, &dpaux_info);
 101         break;
 102         }
 103     case DPAUXMON_EVENT:
 104     case DPAUXMON_START:
 105         proto_tree_add_bitmask(dpauxmon_tree, tvb, 1, hf_inputs, 0, input_fields,
 106                                ENC_BIG_ENDIAN);
 107         break;
 108     case DPAUXMON_STOP:
 109         break;
 110     case DPAUXMON_TS_OVERFLOW:
 111         break;
 112     };
 113
 114     return tvb_captured_length(tvb);
 115 }
 116
 117 void
 118 proto_register_dpauxmon(void)
 119 {
 120     /* Setup protocol subtree array */
 121     static int *ett[] = {
 122         &ett_dpauxmon
 123     };
 124
 125     /* Setup list of header fields  See Section 1.5 of README.dissector for
 126      * details. */
 127     static hf_register_info hf[] = {
 128         { &hf_packet_type,
 129           { "Packet Type", "dpauxmon.packet_type",
 130             FT_UINT8, BASE_DEC, VALS(packet_type_vals), 0,
 131             NULL, HFILL }
 132         },
 133         { &hf_origin,
 134           { "Origin", "dpauxmon.origin",
 135             FT_UINT8, BASE_DEC, VALS(origin_vals), 0,
 136             NULL, HFILL }
 137         },
 138         { &hf_inputs,
 139           { "Inputs", "dpauxmon.inputs",
 140             FT_UINT8, BASE_HEX, NULL, 0,
 141             NULL, HFILL }
 142         },
 143         { &hf_hpd,
 144           { "Hotplug Detect", "dpauxmon.hpd",
 145             FT_BOOLEAN, 4, NULL, 0x1,
 146             NULL, HFILL }
 147         },
 148         { &hf_in0,
 149           { "IN0", "dpauxmon.in0",
 150             FT_BOOLEAN, 4, NULL, 0x2,
 151             NULL, HFILL }
 152         },
 153         { &hf_in1,
 154           { "IN1", "dpauxmon.in1",
 155             FT_BOOLEAN, 4, NULL, 0x4,
 156             NULL, HFILL }
 157         },
 158         { &hf_in2,
 159           { "IN2", "dpauxmon.in2",
 160             FT_BOOLEAN, 4, NULL, 0x8,
 161             NULL, HFILL }
 162         },
 163     };
 164
 165     /* Register the protocol name and description */
 166     proto_dpauxmon = proto_register_protocol("DPAUXMON DisplayPort AUX channel monitor", "DPAUXMON", "dpauxmon");
 167     proto_register_field_array(proto_dpauxmon, hf, array_length(hf));
 168     proto_register_subtree_array(ett, array_length(ett));
 169
 170     dpauxmon_handle = register_dissector("dpauxmon", dissect_dpauxmon, proto_dpauxmon);
 171 }
 172
 173 void
 174 proto_reg_handoff_dpauxmon(void)
 175 {
 176     static bool initialized = false;
 177
 178     dpaux_handle = find_dissector_add_dependency("dpaux", proto_dpauxmon);
 179
 180     if (!initialized) {
 181         initialized = true;
 182     } else {
 183         dissector_delete_uint("wtap_encap", WTAP_ENCAP_DPAUXMON, dpauxmon_handle);
 184     }
 185
 186     dissector_add_uint("wtap_encap", WTAP_ENCAP_DPAUXMON, dpauxmon_handle);
 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  */