epan/dissectors/packet-time.c

   1 /* packet-time.c
   2  * Routines for Time Protocol (RFC 868) packet dissection
   3  *
   4  * Richard Sharpe <rsharpe@ns.aus.com>
   5  *
   6  * Wireshark - Network traffic analyzer
   7  * By Gerald Combs <gerald@wireshark.org>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  * Copied from packet-tftp.c
  11  *
  12  * SPDX-License-Identifier: GPL-2.0-or-later
  13  */
  14
  15 #include "config.h"
  16
  17 #include <epan/packet.h>
  18 #include <epan/prefs.h>
  19 #include <epan/to_str.h>
  20 #include <epan/tfs.h>
  21 #include <wsutil/array.h>
  22
  23 #include <wsutil/epochs.h>
  24
  25 void proto_reg_handoff_time(void);
  26 void proto_register_time(void);
  27
  28 static dissector_handle_t time_handle;
  29
  30 static const enum_val_t time_display_types[] = {
  31     { "UTC", "UTC", ABSOLUTE_TIME_UTC },
  32     { "Local", "Local", ABSOLUTE_TIME_LOCAL},
  33     { NULL, NULL, 0 }
  34 };
  35
  36 static int proto_time;
  37 static int hf_time_time;
  38 static int hf_time_response;
  39
  40 static int ett_time;
  41
  42 /* Use int instead of a field_display_type_e enum to avoid incompatible
  43  * pointer type warnings with prefs_register_enum_preference() */
  44 static int time_display_type = ABSOLUTE_TIME_LOCAL;
  45
  46 /* This dissector works for TCP and UDP time packets */
  47 #define TIME_PORT 37
  48
  49 static int
  50 dissect_time(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  51 {
  52     proto_tree    *time_tree;
  53     proto_item    *ti;
  54
  55     col_set_str(pinfo->cinfo, COL_PROTOCOL, "TIME");
  56
  57     col_add_fstr(pinfo->cinfo, COL_INFO, "TIME %s",
  58             pinfo->srcport == pinfo->match_uint ? "Response":"Request");
  59
  60     ti = proto_tree_add_item(tree, proto_time, tvb, 0, -1, ENC_NA);
  61     time_tree = proto_item_add_subtree(ti, ett_time);
  62
  63     proto_tree_add_boolean(time_tree, hf_time_response, tvb, 0, 0, pinfo->srcport==pinfo->match_uint);
  64     if (pinfo->srcport == pinfo->match_uint) {
  65         /* seconds since 1900-01-01 00:00:00 GMT, *not* 1970 */
  66         uint32_t delta_seconds = tvb_get_ntohl(tvb, 0);
  67         proto_tree_add_uint_format(time_tree, hf_time_time, tvb, 0, 4,
  68                 delta_seconds, "%s",
  69                 abs_time_secs_to_str(pinfo->pool, delta_seconds-EPOCH_DELTA_1900_01_01_00_00_00_UTC,
  70                                         time_display_type, true));
  71     }
  72     return tvb_captured_length(tvb);
  73 }
  74
  75 void
  76 proto_register_time(void)
  77 {
  78     static hf_register_info hf[] = {
  79         { &hf_time_time,
  80             { "Time", "time.time",
  81                 FT_UINT32, BASE_DEC, NULL, 0x0,
  82                 "Seconds since 00:00 (midnight) 1 January 1900 GMT", HFILL }},
  83         { &hf_time_response,
  84             { "Type", "time.response",
  85                 FT_BOOLEAN, BASE_NONE, TFS(&tfs_response_request), 0x0,
  86                 "Response or Request", HFILL }}
  87     };
  88
  89     static int *ett[] = {
  90         &ett_time,
  91     };
  92
  93     module_t *time_pref ;
  94
  95     proto_time = proto_register_protocol("Time Protocol", "TIME", "time");
  96     proto_register_field_array(proto_time, hf, array_length(hf));
  97     proto_register_subtree_array(ett, array_length(ett));
  98     time_handle = register_dissector("time", dissect_time, proto_time);
  99
 100     time_pref = prefs_register_protocol(proto_time, NULL);
 101     prefs_register_enum_preference(time_pref,
 102             "display_time_type",
 103             "Time Display",
 104             "Time display type",
 105             &time_display_type,
 106             time_display_types,
 107             false);
 108 }
 109
 110 void
 111 proto_reg_handoff_time(void)
 112 {
 113     dissector_add_uint_with_preference("udp.port", TIME_PORT, time_handle);
 114     dissector_add_uint_with_preference("tcp.port", TIME_PORT, time_handle);
 115 }
 116
 117 /*
 118  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 119  *
 120  * Local variables:
 121  * c-basic-offset: 4
 122  * tab-width: 8
 123  * indent-tabs-mode: nil
 124  * End:
 125  *
 126  * vi: set shiftwidth=4 tabstop=8 expandtab:
 127  * :indentSize=4:tabSize=8:noTabs=true:
 128  */