forked from osmocom/wireshark
![Pascal Quantin](/assets/img/avatar_default.png)
Change-Id: I6cd8f98518b21e935b329f5470b706ec059c91eb Reviewed-on: https://code.wireshark.org/review/10129 Reviewed-by: Pascal Quantin <pascal.quantin@gmail.com>
277 lines
9.4 KiB
C
277 lines
9.4 KiB
C
/* packet-ixiatrailer.c
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* Routines for Ixia trailer parsing
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*
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* Dissector for Ixia Network Visibility Solutions trailer
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* Copyright Ixia 2012
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "config.h"
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#include <epan/packet.h>
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#include <wsutil/pint.h>
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#include <epan/prefs.h>
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#include <epan/in_cksum.h>
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#include <epan/expert.h>
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void proto_register_ixiatrailer(void);
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void proto_reg_handoff_ixiatrailer(void);
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/* Trailer "magic number". */
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#define IXIA_PATTERN 0xAF12
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/* Trailer TLV types.
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TODO: which of these typestamp types are currently supported?
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Should lose the rest!! */
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#define IXIATRAILER_FTYPE_ORIGINAL_PACKET_SIZE 1
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#define IXIATRAILER_FTYPE_TIMESTAMP_LOCAL 3
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#define IXIATRAILER_FTYPE_TIMESTAMP_NTP 4
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#define IXIATRAILER_FTYPE_TIMESTAMP_GPS 5
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#define IXIATRAILER_FTYPE_TIMESTAMP_1588 6 /* PTP */
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#define IXIATRAILER_FTYPE_TIMESTAMP_HOLDOVER 7
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static const value_string ixiatrailer_ftype_timestamp[] = {
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{ IXIATRAILER_FTYPE_TIMESTAMP_LOCAL, "Local" },
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{ IXIATRAILER_FTYPE_TIMESTAMP_NTP, "NTP" },
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{ IXIATRAILER_FTYPE_TIMESTAMP_GPS, "GPS" },
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{ IXIATRAILER_FTYPE_TIMESTAMP_1588, "PTP" },
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{ IXIATRAILER_FTYPE_TIMESTAMP_HOLDOVER, "Holdover" },
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{ 0, NULL }
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};
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/* Preference settings */
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static gboolean ixiatrailer_summary_in_tree = TRUE;
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static int proto_ixiatrailer = -1;
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static gint ett_ixiatrailer = -1;
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static int hf_ixiatrailer_packetlen = -1;
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static int hf_ixiatrailer_timestamp = -1;
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static int hf_ixiatrailer_generic = -1;
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static expert_field ei_ixiatrailer_field_length_invalid = EI_INIT;
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/* The trailer begins with a sequence of TLVs, each of which has a
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1-byte type, a 1-byte value length (not TLV length, so the TLV
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length is the value length + 2), and a variable-length value.
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Following the sequence of TLVs is:
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a 1-byte field giving the length of the sequence of TLVs;
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a 2-byte big-endian signature field with the value 0xAF12;
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a 2-byte big-endian checksum field, covering the sequence
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of TLVs, the sequence length, and the signature.
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*/
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static int
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dissect_ixiatrailer(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree, void *data _U_)
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{
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proto_tree *ti;
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guint tvblen, trailer_length, field_length;
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gboolean matched_without_fcs, matched_with_fcs;
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proto_tree *ixiatrailer_tree = NULL;
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guint offset = 0;
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guint16 cksum, comp_cksum;
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vec_t vec;
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guint8 field_type;
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/* A trailer must, at minimum, include:
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a "original packet size" TLV, with 1 byte of type, 1 byte of
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value length, and 2 bytes of original packet ize;
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1 byte of trailer length;
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2 bytes of signature;
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2 bytes of trailer checksum;
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for a total of 9 bytes. */
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tvblen = tvb_reported_length(tvb);
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if (tvblen != tvb_captured_length(tvb)) {
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/* The heuristic check includes a checksum check, so we need the
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*entire* trailer to have been captured; if it wasn't, we don't
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try to check it. */
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return 0;
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}
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if (tvblen < 9) {
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/* This is too short, so it cannot be a valid Ixia trailer. */
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return 0;
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}
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/* Depending upon the ethernet preference "Assume packets have FCS", we
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may be given those 4 bytes too.
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Try checking two locations for our pattern. */
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if (tvblen == 23) {
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tvblen = 19;
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}
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/* 3rd & 4th bytes from the end must match our pattern.
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First, try under the assumption that the tvbuff doesn't include
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the FCS. */
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matched_without_fcs = (tvb_get_ntohs(tvb, tvblen-4) == IXIA_PATTERN);
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/* If that didn't match, is the tvbuff big enough to include an Ixia
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trailer *and* an FCS? If so, try under that assumption. */
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if (!matched_without_fcs && tvblen >= 13)
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matched_with_fcs = (tvb_get_ntohs(tvb, tvblen-(4+4)) == IXIA_PATTERN);
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else
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matched_with_fcs = FALSE;
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if (!matched_without_fcs) {
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if (!matched_with_fcs) {
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/* Neither matched, so no Ixia trailer. */
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return 0;
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}
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/* Matched under the assumption that we have an FCS, so let's
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act as if that's the case. Remove the FCS length from the
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tvbuff. */
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tvblen -= 4;
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}
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/* Read Trailer-length field */
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trailer_length = tvb_get_guint8(tvb, tvblen-5);
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/* Should match overall length of trailer */
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if ((tvblen-5) != trailer_length) {
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return 0;
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}
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/* Last 2 bytes are the checksum */
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cksum = tvb_get_ntohs(tvb, tvblen-2);
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/* Verify the checksum; if not valid, it means that the trailer is not valid */
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SET_CKSUM_VEC_TVB(vec, tvb, offset, trailer_length + 3);
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comp_cksum = in_cksum(&vec, 1);
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if (pntoh16(&comp_cksum) != cksum) {
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return 0;
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}
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/* OK: We have our trailer - create protocol root */
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ti = proto_tree_add_item(tree, proto_ixiatrailer, tvb, offset, trailer_length + 5, ENC_NA);
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/* Append summary to item, if configured to */
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if (ixiatrailer_summary_in_tree) {
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proto_item_append_text(ti, ", Length: %u, Checksum: 0x%x", trailer_length, cksum);
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}
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/* Create subtree */
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ixiatrailer_tree = proto_item_add_subtree(ti, ett_ixiatrailer);
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while (offset < trailer_length - 2)
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{
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field_type = tvb_get_guint8(tvb, offset++);
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field_length = tvb_get_guint8(tvb, offset++);
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switch (field_type) {
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case IXIATRAILER_FTYPE_ORIGINAL_PACKET_SIZE:
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if (field_length != 2){
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expert_add_info_format(pinfo, ti, &ei_ixiatrailer_field_length_invalid, "Field length %u invalid", field_length);
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break;
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}
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ti = proto_tree_add_item(ixiatrailer_tree, hf_ixiatrailer_packetlen, tvb, offset, field_length, ENC_BIG_ENDIAN);
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proto_item_append_text(ti, " bytes");
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break;
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case IXIATRAILER_FTYPE_TIMESTAMP_LOCAL:
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case IXIATRAILER_FTYPE_TIMESTAMP_NTP:
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case IXIATRAILER_FTYPE_TIMESTAMP_GPS:
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case IXIATRAILER_FTYPE_TIMESTAMP_1588:
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case IXIATRAILER_FTYPE_TIMESTAMP_HOLDOVER:
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if (field_length != 8) {
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expert_add_info_format(pinfo, ti, &ei_ixiatrailer_field_length_invalid, "Field length %u invalid", field_length);
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break;
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}
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/* Timestamp */
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ti = proto_tree_add_item(ixiatrailer_tree, hf_ixiatrailer_timestamp, tvb, offset, field_length, ENC_TIME_TIMESPEC|ENC_BIG_ENDIAN);
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proto_item_append_text(ti, "; Source: %s", val_to_str_const(field_type, ixiatrailer_ftype_timestamp, "Unknown"));
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break;
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default:
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/* Not a recognized time format - just show as bytes */
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ti = proto_tree_add_item(ixiatrailer_tree, hf_ixiatrailer_generic, tvb, offset, field_length, ENC_NA);
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proto_item_append_text(ti, " [Id: %u, Length: %u bytes]", field_type, field_length);
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break;
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};
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offset += field_length;
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}
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/* We are claiming all of the bytes */
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return tvblen;
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}
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void
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proto_register_ixiatrailer(void)
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{
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static hf_register_info hf[] = {
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{ &hf_ixiatrailer_packetlen, {
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"Original packet length", "ixiatrailer.packetlen", FT_UINT16, BASE_DEC,
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NULL, 0x0, NULL, HFILL }},
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{ &hf_ixiatrailer_timestamp, {
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"Time Stamp", "ixiatrailer.timestamp", FT_ABSOLUTE_TIME, ABSOLUTE_TIME_LOCAL,
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NULL, 0x0, NULL, HFILL }},
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{ &hf_ixiatrailer_generic, {
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"Generic Field", "ixiatrailer.generic", FT_BYTES, BASE_NONE,
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NULL, 0x0, NULL, HFILL }},
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};
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static gint *ixiatrailer_ett[] = {
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&ett_ixiatrailer
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};
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static ei_register_info ei[] = {
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{ &ei_ixiatrailer_field_length_invalid, { "ixiatrailer.field_length_invalid", PI_MALFORMED, PI_ERROR, "Field length invalid", EXPFILL }},
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};
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module_t *ixiatrailer_module;
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expert_module_t* expert_ixiatrailer;
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proto_ixiatrailer = proto_register_protocol("Ixia Trailer", "IXIATRAILER", "ixiatrailer");
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proto_register_field_array(proto_ixiatrailer, hf, array_length(hf));
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proto_register_subtree_array(ixiatrailer_ett, array_length(ixiatrailer_ett));
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expert_ixiatrailer = expert_register_protocol(proto_ixiatrailer);
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expert_register_field_array(expert_ixiatrailer, ei, array_length(ei));
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ixiatrailer_module = prefs_register_protocol(proto_ixiatrailer, NULL);
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prefs_register_bool_preference(ixiatrailer_module, "summary_in_tree",
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"Show trailer summary in protocol tree",
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"Whether the trailer summary line should be shown in the protocol tree",
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&ixiatrailer_summary_in_tree);
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}
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void
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proto_reg_handoff_ixiatrailer(void)
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{
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/* Check for Ixia format in the ethernet trailer */
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heur_dissector_add("eth.trailer", dissect_ixiatrailer, "Ixia Trailer", "ixiatrailer_eth", proto_ixiatrailer, HEURISTIC_ENABLE);
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}
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/*
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* Editor modelines - http://www.wireshark.org/tools/modelines.html
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*
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* Local Variables:
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* c-basic-offset: 2
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* ex: set shiftwidth=2 tabstop=8 expandtab:
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* :indentSize=2:tabSize=8:noTabs=true:
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*/
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