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wireshark/epan/dissectors/packet-metamako.c

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/* packet-metamako.c
* Routines for dissection of Metamako trailers. Forked from
* packet-vssmonitoring.c on 20th December, 2015.
* See https://www.metamako.com for further details.
*
* Copyright VSS-Monitoring 2011
* Copyright Metamako LP 2015
*
* 20111205 - First edition by Sake Blok (sake.blok@SYN-bit.nl)
* 20151220 - Forked to become packet-metamako.c
*
* 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 <epan/packet.h>
#include <epan/etypes.h>
#include <epan/expert.h>
#include <epan/crc32-tvb.h>
#include <glib/gprintf.h>
#define TRAILER_MIN_LENGTH_NO_FCS 16
#define TRAILER_NS_UPPER_BOUND 1000000000
#define TRAILER_SECS_BOUNDS_DFLT "3600-"
#define TRAILER_DAYS_DIFF_LIMIT_DFLT 30
#define SECS_IN_ONE_DAY (60 * 60 * 24)
void proto_register_metamako(void);
void proto_reg_handoff_metamako(void);
/* FCS Options */
static gboolean metamako_check_fcs = TRUE;
static gint metamako_fcs_len = -1; /* By default, try to autodetect the FCS. */
/* Heuristic Options */
static gint metamako_trailer_present = -1; /* By default, try to autodetect the trailer. */
static range_t* metamako_trailer_secs_bounds = NULL;
static guint metamako_trailer_days_diff_limit = TRAILER_DAYS_DIFF_LIMIT_DFLT;
/* Protocols and Header Fields */
static int proto_metamako = -1;
/*
Metamako trailer format
0.............7...............15..............23..............31
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Original FCS |
+---------------+---------------+---------------+---------------+
| ... |
+---------------+---------------+---------------+---------------+
| TLV Extensions |
+---------------+---------------+---------------+---------------+
| ... |
+---------------+---------------+---------------+---------------+
| Seconds |
+---------------+---------------+---------------+---------------+
| Nanoseconds |
+---------------+---------------+---------------+---------------+
| Flags | Device ID | Port ID |
+---------------+---------------+---------------+---------------+
*/
static int hf_metamako_origfcs = -1;
static int hf_metamako_trailerext = -1;
static int hf_metamako_unknownext = -1;
static int hf_metamako_seqnum = -1;
static int hf_metamako_tagstring = -1;
static int hf_metamako_fracns = -1;
static int hf_metamako_crchash = -1;
static int hf_metamako_egress_seqnum = -1;
static int hf_metamako_time_abs = -1;
static int hf_metamako_time_rel = -1;
static int hf_metamako_flags = -1;
static int hf_metamako_src_port = -1;
static int hf_metamako_src_device = -1;
static int hf_metamako_time_diff = -1;
static int hf_metamako_fcs = -1;
static int hf_metamako_fcs_status = -1;
static int hf_metamako_flags_orig_fcs_vld = -1;
static int hf_metamako_flags_has_ext = -1;
static int hf_metamako_flags_duplicate = -1;
static int hf_metamako_flags_ts_degraded = -1;
static int hf_metamako_flags_control_block_type = -1;
static int hf_metamako_reserved = -1;
static gint ett_metamako = -1;
static gint ett_metamako_timestamp = -1;
static gint ett_metamako_extensions = -1;
static gint ett_metamako_flags = -1;
static const enum_val_t metamako_fcs_vals[] = {
{"heuristic", "According to heuristic", -1},
{"never", "Never", 0},
{"always", "Always", 4},
{NULL, NULL, 0}
};
static const enum_val_t metamako_trailer_present_vals[] = {
{"heuristic", "According to heuristic", -1},
{"never", "Never", 0},
{"always", "Always", 1},
{NULL, NULL, 0}
};
static const value_string tfs_pcs49_btf_vals[] = {
{ 0x0, "0x33 or 0x66" },
{ 0x1, "0x78"},
{ 0, NULL }
};
static const value_string tfs_orig_fcs_status_vals[] = {
{ 0x0, "Bad" },
{ 0x1, "Good"},
{ 0, NULL }
};
static int* const flags[] = {
&hf_metamako_flags_control_block_type,
&hf_metamako_flags_ts_degraded,
&hf_metamako_flags_duplicate,
&hf_metamako_flags_has_ext,
&hf_metamako_flags_orig_fcs_vld,
&hf_metamako_reserved,
NULL
};
static expert_field ei_metamako_fcs_bad = EI_INIT;
static void
sub_nanos_base_custom(gchar* result, guint32 value)
{
double temp_double;
temp_double = ((double)value) / (1ULL << 24);
snprintf(result, ITEM_LABEL_LENGTH, "%1.9fns", temp_double);
}
static int
validate_metamako_timestamp(nstime_t* metamako_time, packet_info* pinfo)
{
/* Check that we have a valid nanoseconds field. */
if (metamako_time->nsecs >= TRAILER_NS_UPPER_BOUND)
return 0;
/* Check that the seconds in the trailer timestamp are in the user-specified bounds. */
if (!value_is_in_range(metamako_trailer_secs_bounds, (guint32)metamako_time->secs))
return 0;
/* Check that the number of days between the trailer timestamp
and the capture timestamp are within the user-specified bounds.
Don't use the abs() function because it is not supported on all
platforms and has type ambiguity. */
if (metamako_time->secs > pinfo->abs_ts.secs) {
if (metamako_time->secs - pinfo->abs_ts.secs > (time_t)metamako_trailer_days_diff_limit * SECS_IN_ONE_DAY)
return 0;
}
else {
if (pinfo->abs_ts.secs - metamako_time->secs > (time_t)metamako_trailer_days_diff_limit * SECS_IN_ONE_DAY)
return 0;
}
return 1;
}
static int
dissect_metamako(tvbuff_t* tvb, packet_info* pinfo, proto_tree* tree, void* data _U_)
{
guint i, i_start, i_end, j;
proto_tree* ti, * parent, * item;
proto_tree* metamako_tree, * timestamp_tree;
proto_tree* extensions_tree;
guint offset = 0;
guint captured_trailer_bytes;
guint metamako_trailer_bytes;
guint trailer_min_length;
gboolean trailer_valid;
gboolean has_fcs;
nstime_t metamako_time, time_diff, time_rel;
guint metamako_meta;
guint metamako_tlv_count;
guint metamako_tlv_firstword;
guint metamako_tlv_len;
guint metamako_tlv_tag;
guint metamako_tlv_pos;
guint metamako_tlv_bytes;
guint8 metamako_srcport;
guint16 metamako_srcdevice;
guint8 metamako_flags;
struct tm* tmp;
/* The Metamako trailer is made up of:
4 bytes -- original FCS
N bytes -- trailer extensions
4 bytes -- seconds
4 bytes -- nanoseconds
1 byte -- flags
2 bytes -- device ID
1 byte -- port ID
The new FCS is not a part of the trailer specification,
but it may be passed to this dissector in the course of
dissecting the Ethernet trailer.
If `metamako_fcs_len` is 0, we know it's not present;
if `metamako_fcs_len` is 4, we know it's present;
if `metamako_fcs_len` is -1, we need some heuristics to
determine whether it's present.
4 bytes -- New (valid) FCS (may or may not have been captured)
*/
/* If the user has told us that the Metamako trailer is not present,
then exit immediately. */
if (metamako_trailer_present == 0)
return 0;
/* First get the captured length of the trailer. */
captured_trailer_bytes = tvb_captured_length(tvb);
/* Determine the minimum trailer length required, based on the user's
setting of the assumed FCS capture. */
trailer_min_length = metamako_fcs_len == 4 ? TRAILER_MIN_LENGTH_NO_FCS + 4 : TRAILER_MIN_LENGTH_NO_FCS;
/* If we have less than `trailer_min_length` bytes captured, we can't
read the trailer. */
if (captured_trailer_bytes < trailer_min_length)
return 0;
/* Adjust the state of the loop variables to account for the user options. */
trailer_valid = FALSE;
i_start = metamako_fcs_len == 4 ? 1 : 0;
i_end = metamako_fcs_len == 0 ? 1 : 2;
/* Loop through the trailer bytes, trying to find a valid trailer.
* When:
* i == 0, we assume there IS NO trailing FCS
* i == 1, we assume ther IS a trailing FCS
*/
for (i = i_start; i < i_end && !trailer_valid; i++) {
has_fcs = i == 1;
captured_trailer_bytes -= 4 * i;
metamako_trailer_bytes = captured_trailer_bytes;
/* Start at the tail of the trailer and work inwards. */
metamako_meta = tvb_get_ntohl(tvb, metamako_trailer_bytes - 4);
metamako_flags = (metamako_meta >> 24) & 0xFF;
metamako_trailer_bytes -= 4;
metamako_time.nsecs = tvb_get_ntohl(tvb, metamako_trailer_bytes - 4);
metamako_trailer_bytes -= 4;
metamako_time.secs = tvb_get_ntohl(tvb, metamako_trailer_bytes - 4);
metamako_trailer_bytes -= 4;
/* Check the validity of the candidate timestamp. */
if ((metamako_trailer_present == 1) || validate_metamako_timestamp(&metamako_time, pinfo)) {
metamako_tlv_bytes = 0;
metamako_tlv_count = 0;
/* If the trailer has TLV extensions, "walk" them backwards to the Orig FCS field. */
if (metamako_flags & 0x2) {
/* Extensions are flagged as included, check if there is bytes
* to support this, and try to decode.
*/
while (metamako_trailer_bytes >= 4) {
/* Bytes are here, decode as TLVs. */
metamako_tlv_firstword = tvb_get_ntohl(tvb, metamako_trailer_bytes - 4);
metamako_tlv_count++;
metamako_tlv_bytes += 4;
metamako_trailer_bytes -= 4;
/* Extract length */
metamako_tlv_len = (metamako_tlv_firstword >> 6) & 0x3;
/* If it's a secondary tag header, extract the extended length. */
if ((metamako_tlv_firstword & 0x1F) == 0x1F)
metamako_tlv_len = ((metamako_tlv_firstword >> 6) & 0x3FF) + 1;
/* Skip over the data and find the next tag. We do this in a loop
rather than subtracting `4 * metamako_tlv_len` in case the
dissection has picked up an invalid TLV length in its
heuristic search. This prevents the "walk" from going past the
original length of the trailer. */
while ((metamako_tlv_len > 0) && (metamako_trailer_bytes >= 4)) {
metamako_tlv_len--;
metamako_tlv_bytes += 4;
metamako_trailer_bytes -= 4;
}
/* If this is flagged as the last TLV, stop. */
if ((metamako_tlv_firstword >> 5) & 0x1) {
break;
}
}
}
/* There should be at least enough bytes for the Orig FCS field.
* Any bytes before this are padding. */
if (metamako_trailer_bytes >= 4) {
/* Decrement by the number of bytes in the Orig FCS field. */
metamako_trailer_bytes -= 4;
/* This byte offset is the beginning of the Metamako trailer. */
offset = metamako_trailer_bytes;
/* If we've made it this far, it appears we've got a valid trailer. */
trailer_valid = TRUE;
}
}
}
/* Did we find a valid trailer? */
if (!trailer_valid)
return 0;
/* Everything looks good! Now dissect the trailer. */
col_append_str(pinfo->cinfo, COL_INFO, " with Metamako trailer");
ti = proto_tree_add_item(tree, proto_metamako, tvb, offset, (captured_trailer_bytes - offset), ENC_NA);
metamako_tree = proto_item_add_subtree(ti, ett_metamako);
/* Original FCS */
proto_tree_add_item(metamako_tree, hf_metamako_origfcs, tvb, offset, 4, ENC_BIG_ENDIAN);
offset += 4;
/* TLV Extensions */
if (metamako_tlv_bytes > 0) {
parent = proto_tree_add_item(metamako_tree, hf_metamako_trailerext, tvb, captured_trailer_bytes - 12 - metamako_tlv_bytes, metamako_tlv_bytes, ENC_NA);
extensions_tree = proto_item_add_subtree(parent, ett_metamako_extensions);
while (metamako_tlv_count > 0) {
metamako_tlv_pos = captured_trailer_bytes - 16;
i = metamako_tlv_count;
do {
/* Read TLV word and decode. */
metamako_tlv_firstword = tvb_get_ntohl(tvb, metamako_tlv_pos);
metamako_tlv_len = (metamako_tlv_firstword >> 6) & 0x3;
metamako_tlv_bytes = (metamako_tlv_len * 4) + 3;
metamako_tlv_tag = (metamako_tlv_firstword & 0x1F);
/* If this is a Secondary Tag Header, decode the tag extensions. */
if ((metamako_tlv_firstword & 0x1F) == 0x1F) {
metamako_tlv_len = ((metamako_tlv_firstword >> 6) & 0x3FF) + 1;
metamako_tlv_bytes = (metamako_tlv_len * 4);
metamako_tlv_tag += ((metamako_tlv_firstword >> 16) & 0xFFFF);
}
/* Decrement TLV count. */
i--;
/* Skip over the data if this is not our destination. */
if (i != 0)
metamako_tlv_pos -= (metamako_tlv_len + 1) * 4;
} while (i > 0);
metamako_tlv_pos -= (metamako_tlv_len + 1) * 4;
/* We've skipped to the i-th TLV, decode it. */
switch (metamako_tlv_tag) {
case 0x00:
/* Ingress Sequence Number */
proto_tree_add_item(extensions_tree, hf_metamako_seqnum, tvb, metamako_tlv_pos + 5, 2, ENC_BIG_ENDIAN);
proto_item_append_text(parent, ", Sequence No: %d", tvb_get_ntohs(tvb, metamako_tlv_pos + 5));
break;
case 0x01:
/* Sub-nanoseconds */
proto_tree_add_item(extensions_tree, hf_metamako_fracns, tvb, metamako_tlv_pos + 4, 3, ENC_BIG_ENDIAN);
proto_item_append_text(parent, ", Sub-nanoseconds: %1.9fns", ((double)(tvb_get_ntohl(tvb, metamako_tlv_pos + 3) & 0x00FFFFFF)) / (1ULL << 24));
break;
case 0x02:
/* Deduplication CRC64 Hash */
proto_tree_add_item(extensions_tree, hf_metamako_crchash, tvb, metamako_tlv_pos + 4, 8, ENC_BIG_ENDIAN);
proto_item_append_text(parent, ", CRC64 ECMA Hash: 0x%" PRIx64, tvb_get_ntoh64(tvb, metamako_tlv_pos + 4));
break;
case 0x03:
/* Egress Sequence Number */
proto_tree_add_item(extensions_tree, hf_metamako_egress_seqnum, tvb, metamako_tlv_pos + 4, 3, ENC_BIG_ENDIAN);
proto_item_append_text(parent, ", Egress Sequence No: %d", tvb_get_ntohl(tvb, metamako_tlv_pos + 3) & 0x000FFFFF);
break;
case 0x1F:
/* Tag String */
proto_tree_add_item(extensions_tree, hf_metamako_tagstring, tvb, metamako_tlv_pos + 4, metamako_tlv_len * 4, ENC_ASCII);
break;
default:
/* Unknown tag: just print it's ID and Data. */
item = proto_tree_add_item(extensions_tree, hf_metamako_unknownext, tvb, metamako_tlv_pos + 4, metamako_tlv_bytes, ENC_NA);
/* Start with the Tag */
proto_item_set_text(item, "Unknown Tag [0x%05" PRIx32 "]: ", metamako_tlv_tag);
/* Iterate through the data appending as we go */
for (j = 0; j < metamako_tlv_bytes; j++) {
proto_item_append_text(item, "%02" PRIx8, tvb_get_guint8(tvb, metamako_tlv_pos + 4 + j));
if ((28 + j * 2) >= ITEM_LABEL_LENGTH) {
proto_item_append_text(item, "...");
break;
}
}
break;
}
/* Increment the offset by the Data + Tag size */
offset += (metamako_tlv_len + 1) * 4;
/* Decrement count as we've just decoded a TLV */
metamako_tlv_count--;
}
}
/* Timestamp */
item = proto_tree_add_time(metamako_tree, hf_metamako_time_abs, tvb, offset, 8, &metamako_time);
timestamp_tree = proto_item_add_subtree(item, ett_metamako_timestamp);
tmp = localtime(&metamako_time.secs);
if (tmp)
proto_item_append_text(ti, ", Timestamp: %02d:%02d:%02d.%09ld",
tmp->tm_hour, tmp->tm_min, tmp->tm_sec, (long)metamako_time.nsecs);
else
proto_item_append_text(ti, ", Timestamp: <Not representable>");
/* [Timestamp in seconds] */
item = proto_tree_add_time_item(timestamp_tree, hf_metamako_time_rel, tvb, offset, 8,
ENC_BIG_ENDIAN, &time_rel, NULL, NULL);
proto_item_set_generated(item);
/* [Timestamp difference - capture timestamp minus trailer timestamp] */
nstime_delta(&time_diff, &pinfo->abs_ts, &metamako_time);
item = proto_tree_add_time(timestamp_tree, hf_metamako_time_diff, tvb, offset, 8, &time_diff);
proto_item_set_generated(item);
offset += 8;
/* Flags */
proto_tree_add_bitmask(metamako_tree, tvb, offset, hf_metamako_flags, ett_metamako_flags, flags, ENC_BIG_ENDIAN);
offset++;
/* Source device */
metamako_srcdevice = tvb_get_ntohs(tvb, offset);
proto_tree_add_item(metamako_tree, hf_metamako_src_device, tvb, offset, 2, ENC_BIG_ENDIAN);
proto_item_append_text(ti, ", Source Device: %d", metamako_srcdevice);
offset += 2;
/* Source port */
metamako_srcport = tvb_get_guint8(tvb, offset);
proto_tree_add_item(metamako_tree, hf_metamako_src_port, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_item_append_text(ti, ", Source Port: %d", metamako_srcport);
offset++;
if (has_fcs) {
guint32 sent_fcs = tvb_get_ntohl(tvb, offset);
if (metamako_check_fcs) {
tvbuff_t* parent_tvb = tvb_get_ds_tvb(tvb);
guint32 fcs = crc32_802_tvb(parent_tvb, tvb_captured_length(parent_tvb) - 4);
proto_tree_add_checksum(tree, tvb, offset, hf_metamako_fcs, hf_metamako_fcs_status, &ei_metamako_fcs_bad, pinfo, fcs, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
if (fcs != sent_fcs) {
col_append_str(pinfo->cinfo, COL_INFO, " [ETHERNET FRAME CHECK SEQUENCE INCORRECT]");
}
}
else {
proto_tree_add_checksum(tree, tvb, offset, hf_metamako_fcs, hf_metamako_fcs_status, &ei_metamako_fcs_bad, pinfo, 0, ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS);
}
offset += 4;
}
return offset;
}
void
proto_register_metamako(void)
{
static hf_register_info hf[] = {
{ &hf_metamako_origfcs, {
"Original FCS", "metamako.orig_fcs",
FT_UINT32, BASE_HEX, NULL, 0x0,
NULL, HFILL }},
{ &hf_metamako_trailerext, {
"Trailer Extensions", "metamako.ext",
FT_NONE, BASE_NONE, NULL, 0x0,
NULL, HFILL }},
{ &hf_metamako_unknownext, {
"Unknown Tag", "metamako.unknown",
FT_BYTES, BASE_NONE, NULL, 0x0,
NULL, HFILL }},
{ &hf_metamako_seqnum, {
"Sequence Number", "metamako.seqnum",
FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL }},
{ &hf_metamako_fracns, {
"Sub-nanoseconds", "metamako.subns",
FT_UINT24, BASE_CUSTOM, CF_FUNC(sub_nanos_base_custom), 0x0,
NULL, HFILL }},
{ &hf_metamako_crchash, {
"CRC64 ECMA Hash", "metamako.crchash",
FT_UINT64, BASE_HEX, NULL, 0x0,
NULL, HFILL }},
{ &hf_metamako_egress_seqnum, {
"Egress Sequence Number", "metamako.egrseqnum",
FT_UINT32, BASE_DEC, NULL, 0x0,
NULL, HFILL }},
{ &hf_metamako_tagstring, {
"Tag String", "metamako.tagstring",
FT_STRING, BASE_NONE, NULL, 0x0,
NULL, HFILL }},
{ &hf_metamako_time_abs, {
"Timestamp", "metamako.time.abs",
FT_ABSOLUTE_TIME, ABSOLUTE_TIME_LOCAL, NULL, 0x0,
NULL, HFILL }},
{ &hf_metamako_time_rel, {
"Timestamp", "metamako.time.rel",
FT_RELATIVE_TIME, ENC_BIG_ENDIAN, NULL, 0x0,
NULL, HFILL }},
{ &hf_metamako_time_diff, {
"Time Difference", "metamako.time.diff",
FT_RELATIVE_TIME, BASE_NONE, NULL, 0x0,
"Capture timestamp minus trailer timestamp", HFILL }},
{&hf_metamako_flags, {
"Flags", "metamako.flags",
FT_UINT8, BASE_HEX, NULL, 0x0,
NULL, HFILL}},
{&hf_metamako_reserved, {
"Reserved", "metamako.reserved",
FT_UINT8, BASE_HEX, NULL, 0xC8,
NULL, HFILL}},
{&hf_metamako_flags_control_block_type, {
"Clause 49 BTF", "metamako.flags.pcs49_btf",
FT_UINT8, BASE_HEX, VALS(tfs_pcs49_btf_vals), 0x20,
NULL, HFILL}},
{&hf_metamako_flags_ts_degraded, {
"Timestamp degraded", "metamako.flags.ts_degraded",
FT_BOOLEAN, 8, TFS(&tfs_true_false), 0x10,
NULL, HFILL}},
{&hf_metamako_flags_duplicate, {
"Duplicate Packet", "metamako.flags.is_duplicate",
FT_BOOLEAN, 8, TFS(&tfs_true_false), 0x04,
NULL, HFILL}},
{&hf_metamako_flags_has_ext, {
"Has Trailer Extensions", "metamako.flags.has_extensions",
FT_BOOLEAN, 8, TFS(&tfs_true_false), 0x02,
NULL, HFILL}},
{&hf_metamako_flags_orig_fcs_vld, {
"Original FCS Status", "metamako.flags.orig_fcs_status",
FT_UINT8, BASE_HEX, VALS(tfs_orig_fcs_status_vals), 0x01,
NULL, HFILL}},
{ &hf_metamako_src_device, {
"Source Device ID", "metamako.src.device_id",
FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL }},
{ &hf_metamako_src_port, {
"Source Port", "metamako.src.port",
FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL }},
{ &hf_metamako_fcs, {
"Frame check sequence", "metamako.fcs",
FT_UINT32, BASE_HEX, NULL, 0x0,
"Ethernet checksum", HFILL }},
{ &hf_metamako_fcs_status, {
"FCS Status", "metamako.fcs.status",
FT_UINT8, BASE_NONE, VALS(proto_checksum_vals), 0x0,
NULL, HFILL }},
};
static gint* ett[] = {
&ett_metamako,
&ett_metamako_extensions,
&ett_metamako_timestamp,
&ett_metamako_flags
};
static ei_register_info ei[] = {
{ &ei_metamako_fcs_bad, { "metamako.fcs_bad", PI_CHECKSUM, PI_ERROR, "Bad checksum", EXPFILL }},
};
module_t* metamako_module;
/* Register the Metamako trailer. */
proto_metamako = proto_register_protocol("Metamako ethernet trailer", "Metamako", "metamako");
/* Register header fields. */
proto_register_field_array(proto_metamako, hf, array_length(hf));
/* Register subtree types. */
proto_register_subtree_array(ett, array_length(ett));
/* Register the expert module. */
expert_register_field_array(expert_register_protocol(proto_metamako), ei, array_length(ei));
/* Register configuration preferences */
metamako_module = prefs_register_protocol(proto_metamako, NULL);
range_convert_str(wmem_epan_scope(), &metamako_trailer_secs_bounds, TRAILER_SECS_BOUNDS_DFLT, 0xffffffff);
prefs_register_range_preference(metamako_module, "secs_bounds",
"Heuristic: Bounds of the seconds value in the trailer timestamp",
"If the trailer is found using heuristics, then the trailer may or may not be added "
"and the FCS may or may not be captured. One of the heuristics is the timestamp seconds "
"value being within specified bounds. "
"Set ranges of valid seconds to adjust this particular heuristic.",
&metamako_trailer_secs_bounds, 0xffffffff);
prefs_register_uint_preference(metamako_module, "days_diff_limit",
"Heuristic: Max. number of days difference between capture and trailer timestamps",
"If the trailer is found using heuristics, then the trailer may or may not be added "
"and the FCS may or may not be captured. One of the heuristics is the number of days "
"difference between the capture (PCAP) timestamp and the Ethernet trailer timestamp. "
"Set an upper bound (in days) to adjust this particular heuristic.",
10, &metamako_trailer_days_diff_limit);
prefs_register_enum_preference(metamako_module, "trailer_present",
"Assume packets have a Metamako trailer",
"This option can override the trailer detection heuristic so that the Metamako "
"trailer is either never or always present.",
&metamako_trailer_present, metamako_trailer_present_vals, FALSE);
prefs_register_enum_preference(metamako_module, "fcs",
"Assume packets have FCS",
"Some Ethernet adapters and drivers include the FCS at the end of a packet, others do not. "
"Some capture file formats and protocols do not indicate whether or not the FCS is included. "
"The Metamako dissector attempts to guess whether a captured packet has an FCS, "
"but it cannot always guess correctly. This option can override that heuristic "
"and assume that the FCS is either never or always present.",
&metamako_fcs_len, metamako_fcs_vals, FALSE);
prefs_register_bool_preference(metamako_module, "check_fcs",
"Validate the Ethernet checksum if possible",
"Whether to validate the Frame Check Sequence",
&metamako_check_fcs);
}
void
proto_reg_handoff_metamako(void)
{
heur_dissector_add("eth.trailer", dissect_metamako, "Metamako ethernet trailer", "metamako_eth", proto_metamako, HEURISTIC_DISABLE);
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local Variables:
* c-basic-offset: 2
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* ex: set shiftwidth=2 tabstop=8 expandtab:
* :indentSize=2:tabSize=8:noTabs=true:
*/
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