![Jeff Morriss](/assets/img/avatar_default.png)
(as referenced in https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=2907 ) and https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=3411 : Write a new convenience routine for finding a conversation and, if it is not found, create it. The frame number and addresses are taken from pinfo (as is the common case). Use this function in a bunch of dissectors. svn path=/trunk/; revision=32790
548 lines
18 KiB
C
548 lines
18 KiB
C
/* packet-fix.c
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* Routines for Financial Information eXchange (FIX) Protocol dissection
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* Copyright 2000, PC Drew <drewpc@ibsncentral.com>
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*
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* $Id$
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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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* Documentation: http://www.fixprotocol.org/
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* Fields and messages from http://www.quickfixengine.org/ xml
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*
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <stdlib.h>
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#include <string.h>
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#include <epan/packet.h>
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#include <epan/expert.h>
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#include <epan/prefs.h>
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#include <epan/conversation.h>
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#include "packet-tcp.h"
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typedef struct _fix_field {
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int tag; /* FIX tag */
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int hf_id;
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int type; /* */
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const void *table;
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} fix_field;
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typedef struct _fix_parameter {
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int field_len;
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int tag_len;
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int value_offset;
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int value_len;
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int ctrla_offset;
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} fix_parameter;
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/* Initialize the protocol and registered fields */
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static int proto_fix = -1;
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static dissector_handle_t fix_handle;
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/* desegmentation of fix */
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static gboolean fix_desegment = TRUE;
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/* Initialize the subtree pointers */
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static gint ett_fix = -1;
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static gint ett_unknow = -1;
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static gint ett_badfield = -1;
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static gint ett_checksum = -1;
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static int hf_fix_data = -1; /* continuation data */
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static int hf_fix_checksum_good = -1;
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static int hf_fix_checksum_bad = -1;
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static int hf_fix_field_value = -1;
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static int hf_fix_field_tag = -1;
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static range_t *global_fix_tcp_range = NULL;
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static range_t *fix_tcp_range = NULL;
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/* 8=FIX */
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#define MARKER_TAG "8=FIX"
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#define MARKER_LEN 5
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static int fix_marker(tvbuff_t *tvb, int offset)
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{
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return tvb_strneql(tvb, offset, MARKER_TAG, MARKER_LEN);
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}
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/*
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* Fields and messages generated from http://www.quickfixengine.org/ xml (slightly modified)
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*/
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#include "packet-fix.h"
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static void dissect_fix_init(void) {
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/* TODO load xml def for private field */
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/* TODO check that fix_fields is really sorted */
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}
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static int
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tag_search(int key)
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{
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int lower = 0, upper = array_length(fix_fields) -1;
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while (lower <= upper) {
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int middle = (lower + upper) / 2;
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int res = fix_fields[middle].tag;
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if (res < key) {
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lower = middle + 1;
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} else if (res == key) {
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return middle;
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} else {
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upper = middle - 1;
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}
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}
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return -1;
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}
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/* Code to actually dissect the packets */
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static int fix_next_header(tvbuff_t *tvb, int offset)
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{
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/* try to resynch to the next start */
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guint min_len = tvb_length_remaining(tvb, offset);
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const guint8 *data = tvb_get_ephemeral_string(tvb, offset, min_len);
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const guint8 *start = data;
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while ((start = strstr(start, "\0018"))) {
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min_len = (guint) (start +1 -data);
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/* if remaining length < 6 return and let the next desegment round
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test for 8=FIX
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*/
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if (tvb_length_remaining(tvb, min_len + offset) < MARKER_LEN)
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break;
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if (!fix_marker(tvb, min_len +offset) )
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break;
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start++;
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}
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return min_len;
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}
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/* ----------------------------------------------
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Format: name=value\001
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*/
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static fix_parameter *fix_param(tvbuff_t *tvb, int offset)
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{
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static fix_parameter ret;
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int equals;
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ret.ctrla_offset = tvb_find_guint8(tvb, offset, -1, 0x01);
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if (ret.ctrla_offset == -1) {
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return NULL;
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}
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ret.field_len = ret.ctrla_offset - offset + 1;
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equals = tvb_find_guint8(tvb, offset, ret.field_len, '=');
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if (equals == -1) {
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return NULL;
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}
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ret.value_offset = equals + 1;
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ret.tag_len = ret.value_offset - offset - 1;
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ret.value_len = ret.ctrla_offset - ret.value_offset;
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return &ret;
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}
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/* ---------------------------------------------- */
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static int fix_header_len(tvbuff_t *tvb, int offset)
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{
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int base_offset, ctrla_offset;
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char *value;
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int size;
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fix_parameter *tag;
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base_offset = offset;
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/* get at least the fix version: 8=FIX.x.x */
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if (fix_marker(tvb, offset) != 0) {
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return fix_next_header(tvb, offset);
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}
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/* begin string */
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ctrla_offset = tvb_find_guint8(tvb, offset, -1, 0x01);
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if (ctrla_offset == -1) {
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/* it should be there, (minimum size is big enough)
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* if not maybe it's not really
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* a FIX packet but it's too late to bail out.
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*/
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return fix_next_header(tvb, offset +MARKER_LEN) +MARKER_LEN;
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}
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offset = ctrla_offset + 1;
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/* msg length */
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if (!(tag = fix_param(tvb, offset)) || tvb_strneql(tvb, offset, "9=", 2)) {
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/* not a tag or not the BodyLength tag, give up */
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return fix_next_header(tvb, offset);
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}
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value = tvb_get_ephemeral_string(tvb, tag->value_offset, tag->value_len);
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/* Fix version, msg type, length and checksum aren't in body length.
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* If the packet is big enough find the checksum
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*/
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size = atoi(value) +tag->ctrla_offset - base_offset +1;
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if (tvb_length_remaining(tvb, base_offset) > size +4) {
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/* 10= should be there */
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offset = base_offset +size;
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if (tvb_strneql(tvb, offset, "10=", 3) != 0) {
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/* No? bogus packet, try to find the next header */
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return fix_next_header(tvb, base_offset +MARKER_LEN) +MARKER_LEN;
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}
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ctrla_offset = tvb_find_guint8(tvb, offset, -1, 0x01);
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if (ctrla_offset == -1) {
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/* assume checksum is 7 bytes 10=xxx\01 */
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return size+7;
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}
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return size +ctrla_offset -offset +1;
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}
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else {
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}
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/* assume checksum is 7 bytes 10=xxx\01 */
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return size +7;
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}
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/* ---------------------------------------------- */
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static void
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dissect_fix_packet(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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/* Set up structures needed to add the protocol subtree and manage it */
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proto_item *ti;
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proto_tree *fix_tree;
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int pdu_len;
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int offset = 0;
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int field_offset, ctrla_offset;
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int tag_value;
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char *value;
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char *tag_str;
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fix_parameter *tag;
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int check_sum = 0;
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/* Make entries in Protocol column and Info column on summary display */
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "FIX");
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col_clear(pinfo->cinfo, COL_INFO);
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/* get at least the fix version: 8=FIX.x.x */
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if (fix_marker(tvb, 0) != 0) {
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/* not a fix packet start but it's a fix packet */
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col_set_str(pinfo->cinfo, COL_INFO, "[FIX continuation]");
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ti = proto_tree_add_item(tree, proto_fix, tvb, 0, -1, FALSE);
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fix_tree = proto_item_add_subtree(ti, ett_fix);
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proto_tree_add_item(fix_tree, hf_fix_data, tvb, 0, -1, FALSE);
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return;
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}
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pdu_len = tvb_reported_length(tvb);
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ti = proto_tree_add_item(tree, proto_fix, tvb, 0, -1, FALSE);
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fix_tree = proto_item_add_subtree(ti, ett_fix);
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/* begin string */
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ctrla_offset = tvb_find_guint8(tvb, offset, -1, 0x01);
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if (ctrla_offset == -1) {
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return;
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}
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offset = ctrla_offset + 1;
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/* msg length */
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ctrla_offset = tvb_find_guint8(tvb, offset, -1, 0x01);
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if (ctrla_offset == -1) {
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return;
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}
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offset = ctrla_offset + 1;
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/* msg type */
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if (!(tag = fix_param(tvb, offset)) || tag->value_len < 1) {
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return;
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}
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if (check_col(pinfo->cinfo, COL_INFO)) {
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const char *msg_type;
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value = tvb_get_ephemeral_string(tvb, tag->value_offset, tag->value_len);
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msg_type = str_to_str(value, messages_val, "FIX Message (%s)");
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col_add_str(pinfo->cinfo, COL_INFO, msg_type);
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}
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/* In the interest of speed, if "tree" is NULL, don't do any work not
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* necessary to generate protocol tree items.
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*/
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field_offset = 0;
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while(field_offset < pdu_len && (tag = fix_param(tvb, field_offset)) ) {
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int i, found;
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if (tag->tag_len < 1) {
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field_offset = tag->ctrla_offset + 1;
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continue;
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}
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tag_str = tvb_get_ephemeral_string(tvb, field_offset, tag->tag_len);
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tag_value = atoi(tag_str);
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if (tag->value_len < 1) {
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proto_tree *field_tree;
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/* XXX - put an error indication here. It's too late
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to return FALSE; we've already started dissecting,
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and if a heuristic dissector starts dissecting
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(either updating the columns or creating a protocol
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tree) and then gives up, it leaves crud behind that
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messes up other dissectors that might process the
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packet. */
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ti = proto_tree_add_text(fix_tree, tvb, field_offset, tag->field_len, "%i: <missing value>", tag_value);
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field_tree = proto_item_add_subtree(ti, ett_badfield);
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proto_tree_add_uint(field_tree, hf_fix_field_tag, tvb, field_offset, tag->tag_len, tag_value);
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field_offset = tag->ctrla_offset + 1;
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continue;
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}
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/* fix_fields array is sorted by tag_value */
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found = 0;
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if ((i = tag_search(tag_value)) >= 0) {
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found = 1;
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}
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value = tvb_get_ephemeral_string(tvb, tag->value_offset, tag->value_len);
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if (found) {
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if (fix_fields[i].table) {
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if (tree) {
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switch (fix_fields[i].type) {
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case 1: /* strings */
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proto_tree_add_string_format_value(fix_tree, fix_fields[i].hf_id, tvb, field_offset, tag->field_len, value,
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"%s (%s)", value, str_to_str(value, fix_fields[i].table, "unknow %s"));
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break;
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case 2: /* char */
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proto_tree_add_string_format_value(fix_tree, fix_fields[i].hf_id, tvb, field_offset, tag->field_len, value,
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"%s (%s)", value, val_to_str(*value, fix_fields[i].table, "unknow %d"));
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break;
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default:
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proto_tree_add_string_format_value(fix_tree, fix_fields[i].hf_id, tvb, field_offset, tag->field_len, value,
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"%s (%s)", value, val_to_str(atoi(value), fix_fields[i].table, "unknow %d"));
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break;
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}
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}
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}
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else {
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proto_item *item;
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/* checksum */
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switch(tag_value) {
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case 10:
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{
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proto_tree *checksum_tree;
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guint8 sum = 0;
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const guint8 *data = tvb_get_ptr(tvb, 0, field_offset);
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gboolean sum_ok;
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int j;
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for (j = 0; j < field_offset; j++, data++) {
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sum += *data;
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}
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check_sum = 1;
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sum_ok = (atoi(value) == sum);
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if (sum_ok) {
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item = proto_tree_add_string_format_value(fix_tree, fix_fields[i].hf_id, tvb, field_offset, tag->field_len,
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value, "%s [correct]", value);
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}
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else {
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item = proto_tree_add_string_format_value(fix_tree, fix_fields[i].hf_id, tvb, field_offset, tag->field_len,
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value, "%s [incorrect should be %d]", value, sum);
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}
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checksum_tree = proto_item_add_subtree(item, ett_checksum);
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item = proto_tree_add_boolean(checksum_tree, hf_fix_checksum_good, tvb, field_offset, tag->field_len, sum_ok);
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PROTO_ITEM_SET_GENERATED(item);
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item = proto_tree_add_boolean(checksum_tree, hf_fix_checksum_bad, tvb, field_offset, tag->field_len, !sum_ok);
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PROTO_ITEM_SET_GENERATED(item);
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if (!sum_ok)
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expert_add_info_format(pinfo, item, PI_CHECKSUM, PI_ERROR, "Bad checksum");
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}
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break;
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default:
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item = proto_tree_add_string(fix_tree, fix_fields[i].hf_id, tvb, field_offset, tag->field_len, value);
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break;
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}
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}
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}
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else if (tree) {
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proto_tree *field_tree;
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/* XXX - it could be -1 if the tag isn't a number */
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ti = proto_tree_add_text(fix_tree, tvb, field_offset, tag->field_len, "%i: %s", tag_value, value);
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field_tree = proto_item_add_subtree(ti, ett_unknow);
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proto_tree_add_uint(field_tree, hf_fix_field_tag, tvb, field_offset, tag->tag_len, tag_value);
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proto_tree_add_item(field_tree, hf_fix_field_value, tvb, tag->value_offset, tag->value_len, FALSE);
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}
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field_offset = tag->ctrla_offset + 1;
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tag_str = NULL;
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}
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return;
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}
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static guint
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get_fix_pdu_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset)
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{
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int fix_len;
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fix_len = fix_header_len(tvb, offset);
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return fix_len;
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}
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/* ------------------------------------
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fixed-length part isn't really a constant but if we assume it's at least:
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8=FIX.x.y\01 10
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9=x\01 4
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35=x\01 5
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10=y\01 5
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24
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it should catch all 9= size
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*/
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#define FIX_MIN_LEN 24
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static void
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dissect_fix_pdus(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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tcp_dissect_pdus(tvb, pinfo, tree, fix_desegment, FIX_MIN_LEN,
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get_fix_pdu_len, dissect_fix_packet);
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}
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static void
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dissect_fix(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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dissect_fix_pdus(tvb, pinfo, tree);
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}
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/* Code to actually dissect the packets */
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static gboolean
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dissect_fix_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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conversation_t *conv;
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/* get at least the fix version: 8=FIX.x.x */
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if (fix_marker(tvb, 0) != 0) {
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/* not a fix packet */
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return FALSE;
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}
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conv = find_or_create_conversation(pinfo);
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conversation_set_dissector(conv, fix_handle);
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dissect_fix_pdus(tvb, pinfo, tree);
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return TRUE;
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}
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/* Register the protocol with Wireshark */
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static void range_delete_fix_tcp_callback(guint32 port) {
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dissector_delete("tcp.port", port, fix_handle);
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}
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static void range_add_fix_tcp_callback(guint32 port) {
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dissector_add("tcp.port", port, fix_handle);
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}
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static void fix_prefs(void)
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{
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range_foreach(fix_tcp_range, range_delete_fix_tcp_callback);
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g_free(fix_tcp_range);
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fix_tcp_range = range_copy(global_fix_tcp_range);
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range_foreach(fix_tcp_range, range_add_fix_tcp_callback);
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}
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/* this format is require because a script is used to build the C function
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that calls all the protocol registration.
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*/
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void
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proto_register_fix(void)
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{
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/* Setup list of header fields See Section 1.6.1 for details*/
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static hf_register_info hf[] = {
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{ &hf_fix_data,
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{ "Continuation Data", "fix.data", FT_BYTES, BASE_NONE, NULL, 0x00,
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NULL, HFILL }
|
|
},
|
|
|
|
{ &hf_fix_field_tag,
|
|
{ "Field Tag", "fix.field.tag", FT_UINT16, BASE_DEC, NULL, 0x0,
|
|
"Field length.", HFILL }},
|
|
|
|
{ &hf_fix_field_value,
|
|
{ "Field Value", "fix.field.value", FT_STRING, BASE_NONE, NULL, 0x0,
|
|
"Field value", HFILL }},
|
|
|
|
{ &hf_fix_checksum_good,
|
|
{ "Good Checksum", "fix.checksum_good", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
|
|
"True: checksum matches packet content; False: doesn't match content or not checked", HFILL }},
|
|
|
|
{ &hf_fix_checksum_bad,
|
|
{ "Bad Checksum", "fix.checksum_bad", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
|
|
"True: checksum doesn't match packet content; False: matches content or not checked", HFILL }},
|
|
};
|
|
|
|
/* Setup protocol subtree array */
|
|
static gint *ett[] = {
|
|
&ett_fix,
|
|
&ett_unknow,
|
|
&ett_badfield,
|
|
&ett_checksum,
|
|
};
|
|
|
|
module_t *fix_module;
|
|
|
|
/* register re-init routine */
|
|
register_init_routine(&dissect_fix_init);
|
|
|
|
/* Register the protocol name and description */
|
|
proto_fix = proto_register_protocol("Financial Information eXchange Protocol",
|
|
"FIX", "fix");
|
|
|
|
/* Required function calls to register the header fields and subtrees used */
|
|
proto_register_field_array(proto_fix, hf, array_length(hf));
|
|
proto_register_field_array(proto_fix, hf_FIX, array_length(hf_FIX));
|
|
proto_register_subtree_array(ett, array_length(ett));
|
|
|
|
fix_module = prefs_register_protocol(proto_fix, fix_prefs);
|
|
prefs_register_bool_preference(fix_module, "desegment",
|
|
"Reassemble FIX messages spanning multiple TCP segments",
|
|
"Whether the FIX dissector should reassemble messages spanning multiple TCP segments."
|
|
" To use this option, you must also enable \"Allow subdissectors to reassemble TCP streams\" in the TCP protocol settings.",
|
|
&fix_desegment);
|
|
|
|
prefs_register_range_preference(fix_module, "tcp.port", "TCP Ports", "TCP Ports range", &global_fix_tcp_range, 65535);
|
|
|
|
fix_tcp_range = range_empty();
|
|
}
|
|
|
|
|
|
/* If this dissector uses sub-dissector registration add a registration routine.
|
|
This format is required because a script is used to find these routines and
|
|
create the code that calls these routines.
|
|
*/
|
|
void
|
|
proto_reg_handoff_fix(void)
|
|
{
|
|
/* Let the tcp dissector know that we're interested in traffic */
|
|
heur_dissector_add("tcp", dissect_fix_heur, proto_fix);
|
|
/* Register a fix handle to "tcp.port" to be able to do 'decode-as' */
|
|
fix_handle = create_dissector_handle(dissect_fix, proto_fix);
|
|
dissector_add_handle("tcp.port", fix_handle);
|
|
}
|
|
|