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/* packet-exablaze.c
* Routines for dissection of Exablaze trailers
* Copyright 2018 Exablaze
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <math.h>
#include <epan/packet.h>
void proto_register_exablaze(void);
void proto_reg_handoff_exablaze(void);
static int proto_exablaze = -1;
static int hf_exablaze_original_fcs = -1;
static int hf_exablaze_device = -1;
static int hf_exablaze_port = -1;
static int hf_exablaze_timestamp = -1;
static int hf_exablaze_timestamp_integer = -1;
static int hf_exablaze_timestamp_fractional = -1;
static gint ett_exablaze = -1;
static gint ett_exablaze_timestamp = -1;
static int
dissect_exablaze(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
void *data _U_)
{
proto_item *ti;
proto_tree *exablaze_tree;
proto_tree *timestamp_tree;
guint trailer_length;
guint fcs_length;
guint offset;
gboolean trailer_found;
guint8 device;
guint8 port;
guint32 timestamp_sec;
guint64 timestamp_frac;
nstime_t timestamp;
double timestamp_frac_double;
struct tm *tm;
trailer_length = tvb_reported_length(tvb);
if (trailer_length != tvb_captured_length(tvb)) {
/* The heuristics require the whole trailer to be captured */
return 0;
}
/* Try matching with and without FCS */
trailer_found = FALSE;
for (fcs_length = 0; fcs_length <= 4; fcs_length += 4)
{
if (trailer_length < fcs_length + 16)
continue;
offset = trailer_length - fcs_length - 16;
device = tvb_get_guint8(tvb, offset + 4);
port = tvb_get_guint8(tvb, offset + 5);
timestamp_sec = tvb_get_ntohl(tvb, offset + 6);
timestamp_frac = tvb_get_ntoh40(tvb, offset + 10);
/* If the capture time and timestamp differ by more than a week,
* then this is probably not a valid Exablaze trailer */
if (timestamp_sec > (guint)pinfo->abs_ts.secs) {
if (timestamp_sec - pinfo->abs_ts.secs > 604800)
continue;
} else {
if (pinfo->abs_ts.secs - timestamp_sec > 604800)
continue;
}
trailer_found = TRUE;
break;
}
if (!trailer_found)
return 0;
/* Fractional part is a 40 bit binary fraction of a second */
timestamp.secs = timestamp_sec;
timestamp_frac_double = ldexp((double)timestamp_frac, -40);
timestamp.nsecs = (int)(timestamp_frac_double * 1000000000);
ti = proto_tree_add_item(tree, proto_exablaze, tvb, offset, 16, ENC_NA);
proto_item_append_text(ti, ", Device: %u, Port: %u, Timestamp: ",
device, port);
tm = localtime(×tamp.secs);
if (tm)
proto_item_append_text(ti, "%02u:%02u:%02.12f",
tm->tm_hour, tm->tm_min, tm->tm_sec + timestamp_frac_double);
else
proto_item_append_text(ti, "<Not representable>");
exablaze_tree = proto_item_add_subtree(ti, ett_exablaze);
proto_tree_add_item(exablaze_tree, hf_exablaze_original_fcs, tvb,
offset, 4, ENC_BIG_ENDIAN);
proto_tree_add_item(exablaze_tree, hf_exablaze_device, tvb,
offset + 4, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(exablaze_tree, hf_exablaze_port, tvb,
offset + 5, 1, ENC_BIG_ENDIAN);
ti = proto_tree_add_time(exablaze_tree, hf_exablaze_timestamp, tvb,
offset + 6, 9, ×tamp);
timestamp_tree = proto_item_add_subtree(ti, ett_exablaze_timestamp);
proto_tree_add_item(timestamp_tree, hf_exablaze_timestamp_integer, tvb,
offset + 6, 4, ENC_BIG_ENDIAN);
proto_tree_add_double_format_value(timestamp_tree,
hf_exablaze_timestamp_fractional, tvb, offset + 10, 5,
timestamp_frac_double, "%.12f", timestamp_frac_double);
return offset + 16;
}
void
proto_register_exablaze(void)
{
static hf_register_info hf[] = {
{
&hf_exablaze_original_fcs,
{
"Original FCS", "exablaze.original_fcs",
FT_UINT32, BASE_HEX, NULL, 0x0, NULL, HFILL
}
},
{
&hf_exablaze_device,
{
"Device ID", "exablaze.device",
FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL
}
},
{
&hf_exablaze_port,
{
"Port", "exablaze.port",
FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL
}
},
{
&hf_exablaze_timestamp,
{
"Timestamp", "exablaze.timestamp",
FT_ABSOLUTE_TIME, ABSOLUTE_TIME_LOCAL, NULL, 0x0, NULL, HFILL
}
},
{ &hf_exablaze_timestamp_integer,
{
"Seconds since epoch", "exablaze.timestamp.seconds",
FT_UINT32, BASE_DEC, NULL, 0x0, NULL, HFILL
}
},
{ &hf_exablaze_timestamp_fractional,
{
"Fractional seconds",
"exablaze.timestamp.fractional_seconds",
FT_DOUBLE, BASE_NONE, NULL, 0x0, NULL, HFILL
}
}
};
static gint *ett[] = {
&ett_exablaze,
&ett_exablaze_timestamp
};
proto_exablaze = proto_register_protocol("Exablaze trailer", "Exablaze",
"exablaze");
proto_register_field_array(proto_exablaze, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
void
proto_reg_handoff_exablaze(void)
{
heur_dissector_add("eth.trailer", dissect_exablaze, "Exablaze trailer",
"exablaze_eth", proto_exablaze, HEURISTIC_DISABLE);
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
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