![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
560 lines
16 KiB
C
560 lines
16 KiB
C
/* packet-tftp.c
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* Routines for tftp packet dissection
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*
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* Richard Sharpe <rsharpe@ns.aus.com>
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* Craig Newell <CraigN@cheque.uq.edu.au>
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* RFC2347 TFTP Option Extension
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* Joerg Mayer (see AUTHORS file)
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* RFC2348 TFTP Blocksize Option
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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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* Copied from packet-bootp.c
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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:
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* RFC 1350: THE TFTP PROTOCOL (REVISION 2)
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* RFC 2090: TFTP Multicast Option
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* (not yet implemented)
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* RFC 2347: TFTP Option Extension
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* RFC 2348: TFTP Blocksize Option
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* RFC 2349: TFTP Timeout Interval and Transfer Size Options
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* (not yet implemented)
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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 <glib.h>
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#include <stdlib.h>
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#include <epan/packet.h>
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#include <epan/conversation.h>
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#include <epan/emem.h>
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#include <epan/expert.h>
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#include <epan/range.h>
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#include <epan/prefs.h>
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/* Things we may want to remember for a whole conversation */
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typedef struct _tftp_conv_info_t {
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guint16 blocksize;
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gchar *source_file, *destination_file;
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} tftp_conv_info_t;
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static int proto_tftp = -1;
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static int hf_tftp_opcode = -1;
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static int hf_tftp_source_file = -1;
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static int hf_tftp_destination_file = -1;
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static int hf_tftp_transfer_type = -1;
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static int hf_tftp_blocknum = -1;
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static int hf_tftp_error_code = -1;
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static int hf_tftp_error_string = -1;
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static int hf_tftp_option_name = -1;
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static int hf_tftp_option_value = -1;
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static gint ett_tftp = -1;
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static gint ett_tftp_option = -1;
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static dissector_handle_t tftp_handle;
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#define UDP_PORT_TFTP_RANGE "69"
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void proto_reg_handoff_tftp (void);
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/* User definable values */
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static range_t *global_tftp_port_range;
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#define TFTP_RRQ 1
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#define TFTP_WRQ 2
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#define TFTP_DATA 3
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#define TFTP_ACK 4
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#define TFTP_ERROR 5
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#define TFTP_OACK 6
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#define TFTP_INFO 255
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static const value_string tftp_opcode_vals[] = {
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{ TFTP_RRQ, "Read Request" },
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{ TFTP_WRQ, "Write Request" },
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{ TFTP_DATA, "Data Packet" },
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{ TFTP_ACK, "Acknowledgement" },
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{ TFTP_ERROR, "Error Code" },
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{ TFTP_OACK, "Option Acknowledgement" },
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{ TFTP_INFO, "Information (MSDP)" },
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{ 0, NULL }
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};
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static const value_string tftp_error_code_vals[] = {
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{ 0, "Not defined" },
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{ 1, "File not found" },
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{ 2, "Access violation" },
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{ 3, "Disk full or allocation exceeded" },
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{ 4, "Illegal TFTP Operation" },
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{ 5, "Unknown transfer ID" }, /* Does not cause termination */
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{ 6, "File already exists" },
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{ 7, "No such user" },
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{ 8, "Option negotiation failed" },
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{ 0, NULL }
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};
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static void
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tftp_dissect_options(tvbuff_t *tvb, packet_info *pinfo, int offset,
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proto_tree *tree, guint16 opcode, tftp_conv_info_t *tftp_info)
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{
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int option_len, value_len;
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int value_offset;
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const char *optionname;
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const char *optionvalue;
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proto_item *opt_item;
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proto_tree *opt_tree;
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while (tvb_offset_exists(tvb, offset)) {
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option_len = tvb_strsize(tvb, offset); /* length of option */
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value_offset = offset + option_len;
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value_len = tvb_strsize(tvb, value_offset); /* length of value */
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optionname = tvb_format_text(tvb, offset, option_len);
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optionvalue = tvb_format_text(tvb, value_offset, value_len);
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opt_item = proto_tree_add_text(tree, tvb, offset, option_len+value_len,
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"Option: %s = %s", optionname, optionvalue);
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opt_tree = proto_item_add_subtree(opt_item, ett_tftp_option);
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proto_tree_add_item(opt_tree, hf_tftp_option_name, tvb, offset,
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option_len, FALSE);
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proto_tree_add_item(opt_tree, hf_tftp_option_value, tvb, value_offset,
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value_len, FALSE);
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offset += option_len + value_len;
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if (check_col(pinfo->cinfo, COL_INFO)) {
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col_append_fstr(pinfo->cinfo, COL_INFO, ", %s=%s",
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optionname, optionvalue);
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}
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/* Special code to handle individual options */
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if (!g_ascii_strcasecmp((const char *)optionname, "blksize") &&
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opcode == TFTP_OACK) {
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gint blocksize = strtol((const char *)optionvalue, NULL, 10);
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if (blocksize < 8 || blocksize > 65464) {
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expert_add_info_format(pinfo, NULL, PI_RESPONSE_CODE,
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PI_WARN, "TFTP blocksize out of range");
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} else {
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tftp_info->blocksize = blocksize;
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}
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}
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}
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}
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static void dissect_tftp_message(tftp_conv_info_t *tftp_info,
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tvbuff_t *tvb, packet_info *pinfo,
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proto_tree *tree)
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{
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proto_tree *tftp_tree = NULL;
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proto_item *ti;
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gint offset = 0;
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guint16 opcode;
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guint16 bytes;
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guint16 blocknum;
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guint i1;
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guint16 error;
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "TFTP");
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opcode = tvb_get_ntohs(tvb, offset);
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if (check_col(pinfo->cinfo, COL_INFO)) {
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col_add_str(pinfo->cinfo, COL_INFO,
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val_to_str(opcode, tftp_opcode_vals, "Unknown (0x%04x)"));
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}
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if (tree) {
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ti = proto_tree_add_item(tree, proto_tftp, tvb, offset, -1, FALSE);
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tftp_tree = proto_item_add_subtree(ti, ett_tftp);
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if(tftp_info->source_file) {
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ti = proto_tree_add_string(tftp_tree, hf_tftp_source_file, tvb,
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0, 0, tftp_info->source_file);
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PROTO_ITEM_SET_GENERATED(ti);
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}
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if(tftp_info->destination_file) {
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ti = proto_tree_add_string(tftp_tree, hf_tftp_destination_file, tvb,
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0, 0, tftp_info->destination_file);
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PROTO_ITEM_SET_GENERATED(ti);
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}
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proto_tree_add_uint(tftp_tree, hf_tftp_opcode, tvb,
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offset, 2, opcode);
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}
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offset += 2;
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switch (opcode) {
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case TFTP_RRQ:
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i1 = tvb_strsize(tvb, offset);
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if (tree) {
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proto_tree_add_item(tftp_tree, hf_tftp_source_file,
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tvb, offset, i1, FALSE);
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}
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tftp_info->source_file = tvb_get_seasonal_string(tvb, offset, i1);
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if (check_col(pinfo->cinfo, COL_INFO)) {
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col_append_fstr(pinfo->cinfo, COL_INFO, ", File: %s",
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tvb_format_text(tvb, offset, i1));
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}
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offset += i1;
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i1 = tvb_strsize(tvb, offset);
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if (tree) {
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ti = proto_tree_add_item(tftp_tree, hf_tftp_transfer_type,
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tvb, offset, i1, FALSE);
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}
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if (check_col(pinfo->cinfo, COL_INFO)) {
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col_append_fstr(pinfo->cinfo, COL_INFO, ", Transfer type: %s",
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tvb_format_text(tvb, offset, i1));
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}
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offset += i1;
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if (tree)
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tftp_dissect_options(tvb, pinfo, offset, tftp_tree,
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opcode, tftp_info);
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break;
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case TFTP_WRQ:
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i1 = tvb_strsize(tvb, offset);
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if (tree) {
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proto_tree_add_item(tftp_tree, hf_tftp_destination_file,
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tvb, offset, i1, FALSE);
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}
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tftp_info->destination_file =
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tvb_get_seasonal_string(tvb, offset, i1);
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if (check_col(pinfo->cinfo, COL_INFO)) {
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col_append_fstr(pinfo->cinfo, COL_INFO, ", File: %s",
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tvb_format_text(tvb, offset, i1));
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}
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offset += i1;
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i1 = tvb_strsize(tvb, offset);
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if (tree) {
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ti = proto_tree_add_item(tftp_tree, hf_tftp_transfer_type,
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tvb, offset, i1, FALSE);
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}
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if (check_col(pinfo->cinfo, COL_INFO)) {
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col_append_fstr(pinfo->cinfo, COL_INFO, ", Transfer type: %s",
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tvb_format_text(tvb, offset, i1));
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}
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offset += i1;
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if (tree)
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tftp_dissect_options(tvb, pinfo, offset, tftp_tree,
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opcode, tftp_info);
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break;
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case TFTP_INFO:
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if (tree)
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tftp_dissect_options(tvb, pinfo, offset, tftp_tree,
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opcode, tftp_info);
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break;
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case TFTP_DATA:
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blocknum = tvb_get_ntohs(tvb, offset);
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if (tree) {
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proto_tree_add_uint(tftp_tree, hf_tftp_blocknum, tvb, offset, 2,
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blocknum);
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}
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offset += 2;
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bytes = tvb_reported_length_remaining(tvb, offset);
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if (check_col(pinfo->cinfo, COL_INFO)) {
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col_append_fstr(pinfo->cinfo, COL_INFO, ", Block: %i%s",
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blocknum,
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(bytes < tftp_info->blocksize)?" (last)":"" );
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}
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if (bytes != 0) {
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if (tree) {
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proto_tree_add_text(tftp_tree, tvb, offset, -1,
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"Data (%d bytes)", bytes);
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}
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}
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break;
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case TFTP_ACK:
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blocknum = tvb_get_ntohs(tvb, offset);
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if (tree) {
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proto_tree_add_uint(tftp_tree, hf_tftp_blocknum, tvb, offset, 2,
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blocknum);
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}
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if (check_col(pinfo->cinfo, COL_INFO)) {
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col_append_fstr(pinfo->cinfo, COL_INFO, ", Block: %i",
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blocknum);
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}
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break;
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case TFTP_ERROR:
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error = tvb_get_ntohs(tvb, offset);
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if (tree) {
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proto_tree_add_uint(tftp_tree, hf_tftp_error_code, tvb, offset, 2,
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error);
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}
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if (check_col(pinfo->cinfo, COL_INFO)) {
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col_append_fstr(pinfo->cinfo, COL_INFO, ", Code: %s",
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val_to_str(error, tftp_error_code_vals, "Unknown (%u)"));
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}
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offset += 2;
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i1 = tvb_strsize(tvb, offset);
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if (tree) {
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proto_tree_add_item(tftp_tree, hf_tftp_error_string, tvb, offset,
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i1, FALSE);
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}
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if (check_col(pinfo->cinfo, COL_INFO)) {
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col_append_fstr(pinfo->cinfo, COL_INFO, ", Message: %s",
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tvb_format_text(tvb, offset, i1));
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}
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expert_add_info_format(pinfo, NULL, PI_RESPONSE_CODE,
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PI_NOTE, "TFTP blocksize out of range");
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break;
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case TFTP_OACK:
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if (tree)
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tftp_dissect_options(tvb, pinfo, offset, tftp_tree,
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opcode, tftp_info);
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break;
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default:
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if (tree) {
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proto_tree_add_text(tftp_tree, tvb, offset, -1,
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"Data (%d bytes)", tvb_reported_length_remaining(tvb, offset));
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}
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break;
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}
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return;
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}
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static gboolean
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dissect_embeddedtftp_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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/* Used to dissect TFTP packets where one can not assume
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that the TFTP is the only protocol used by that port, and
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that TFTP may not be carried by UDP */
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conversation_t *conversation = NULL;
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guint16 opcode;
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tftp_conv_info_t *tftp_info;
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conversation = find_or_create_conversation(pinfo);
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tftp_info = conversation_get_proto_data(conversation, proto_tftp);
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if (!tftp_info) {
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tftp_info = se_alloc(sizeof(tftp_conv_info_t));
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tftp_info->blocksize = 512; /* TFTP default block size */
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tftp_info->source_file = NULL;
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tftp_info->destination_file = NULL;
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conversation_add_proto_data(conversation, proto_tftp, tftp_info);
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}
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opcode = tvb_get_ntohs(tvb, 0);
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if ((opcode == TFTP_RRQ) ||
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(opcode == TFTP_WRQ) ||
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(opcode == TFTP_DATA) ||
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(opcode == TFTP_ACK) ||
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(opcode == TFTP_ERROR) ||
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(opcode == TFTP_INFO) ||
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(opcode == TFTP_OACK)) {
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dissect_tftp_message(tftp_info, tvb, pinfo, tree);
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return TRUE;
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}
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else {
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return FALSE;
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}
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}
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static void
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dissect_tftp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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conversation_t *conversation = NULL;
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tftp_conv_info_t *tftp_info;
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/*
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* The first TFTP packet goes to the TFTP port; the second one
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* comes from some *other* port, but goes back to the same
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* IP address and port as the ones from which the first packet
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* came; all subsequent packets go between those two IP addresses
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* and ports.
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*
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* If this packet went to the TFTP port, we check to see if
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* there's already a conversation with one address/port pair
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* matching the source IP address and port of this packet,
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* the other address matching the destination IP address of this
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* packet, and any destination port.
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*
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* If not, we create one, with its address 1/port 1 pair being
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* the source address/port of this packet, its address 2 being
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* the destination address of this packet, and its port 2 being
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* wildcarded, and give it the TFTP dissector as a dissector.
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*/
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if (value_is_in_range(global_tftp_port_range, pinfo->destport)) {
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conversation = find_conversation(pinfo->fd->num, &pinfo->src, &pinfo->dst, PT_UDP,
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pinfo->srcport, 0, NO_PORT_B);
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if( (conversation == NULL) || (conversation->dissector_handle!=tftp_handle) ){
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conversation = conversation_new(pinfo->fd->num, &pinfo->src, &pinfo->dst, PT_UDP,
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pinfo->srcport, 0, NO_PORT2);
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conversation_set_dissector(conversation, tftp_handle);
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}
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} else {
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conversation = find_conversation(pinfo->fd->num, &pinfo->src, &pinfo->dst,
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pinfo->ptype, pinfo->srcport, pinfo->destport, 0);
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if( (conversation == NULL) || (conversation->dissector_handle!=tftp_handle) ){
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conversation = conversation_new(pinfo->fd->num, &pinfo->src, &pinfo->dst, PT_UDP,
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pinfo->destport, pinfo->srcport, 0);
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conversation_set_dissector(conversation, tftp_handle);
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}
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}
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tftp_info = conversation_get_proto_data(conversation, proto_tftp);
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if (!tftp_info) {
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tftp_info = se_alloc(sizeof(tftp_conv_info_t));
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tftp_info->blocksize = 512; /* TFTP default block size */
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tftp_info->source_file = NULL;
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tftp_info->destination_file = NULL;
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conversation_add_proto_data(conversation, proto_tftp, tftp_info);
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}
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dissect_tftp_message(tftp_info, tvb, pinfo, tree);
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return;
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}
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void
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proto_register_tftp(void)
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{
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static hf_register_info hf[] = {
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{ &hf_tftp_opcode,
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{ "Opcode", "tftp.opcode",
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FT_UINT16, BASE_DEC, VALS(tftp_opcode_vals), 0x0,
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"TFTP message type", HFILL }},
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{ &hf_tftp_source_file,
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{ "Source File", "tftp.source_file",
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FT_STRINGZ, BASE_NONE, NULL, 0x0,
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"TFTP source file name", HFILL }},
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|
|
|
{ &hf_tftp_destination_file,
|
|
{ "DESTINATION File", "tftp.destination_file",
|
|
FT_STRINGZ, BASE_NONE, NULL, 0x0,
|
|
"TFTP source file name", HFILL }},
|
|
|
|
{ &hf_tftp_transfer_type,
|
|
{ "Type", "tftp.type",
|
|
FT_STRINGZ, BASE_NONE, NULL, 0x0,
|
|
"TFTP transfer type", HFILL }},
|
|
|
|
{ &hf_tftp_blocknum,
|
|
{ "Block", "tftp.block",
|
|
FT_UINT16, BASE_DEC, NULL, 0x0,
|
|
"Block number", HFILL }},
|
|
|
|
{ &hf_tftp_error_code,
|
|
{ "Error code", "tftp.error.code",
|
|
FT_UINT16, BASE_DEC, VALS(tftp_error_code_vals), 0x0,
|
|
"Error code in case of TFTP error message", HFILL }},
|
|
|
|
{ &hf_tftp_error_string,
|
|
{ "Error message", "tftp.error.message",
|
|
FT_STRINGZ, BASE_NONE, NULL, 0x0,
|
|
"Error string in case of TFTP error message", HFILL }},
|
|
|
|
{ &hf_tftp_option_name,
|
|
{ "Option name", "tftp.option.name",
|
|
FT_STRINGZ, BASE_NONE, NULL, 0x0,
|
|
NULL, HFILL }},
|
|
|
|
{ &hf_tftp_option_value,
|
|
{ "Option value", "tftp.option.value",
|
|
FT_STRINGZ, BASE_NONE, NULL, 0x0,
|
|
NULL, HFILL }},
|
|
|
|
};
|
|
static gint *ett[] = {
|
|
&ett_tftp,
|
|
&ett_tftp_option,
|
|
};
|
|
|
|
module_t *tftp_module;
|
|
|
|
proto_tftp = proto_register_protocol("Trivial File Transfer Protocol",
|
|
"TFTP", "tftp");
|
|
proto_register_field_array(proto_tftp, hf, array_length(hf));
|
|
proto_register_subtree_array(ett, array_length(ett));
|
|
|
|
register_dissector("tftp", dissect_tftp, proto_tftp);
|
|
|
|
/* Set default UDP ports */
|
|
range_convert_str (&global_tftp_port_range, UDP_PORT_TFTP_RANGE, MAX_UDP_PORT);
|
|
|
|
tftp_module = prefs_register_protocol (proto_tftp, proto_reg_handoff_tftp);
|
|
prefs_register_range_preference (tftp_module, "udp_ports",
|
|
"TFTP port numbers",
|
|
"Port numbers used for TFTP traffic "
|
|
"(default " UDP_PORT_TFTP_RANGE ")",
|
|
&global_tftp_port_range, MAX_UDP_PORT);
|
|
}
|
|
|
|
static void range_delete_callback (guint32 port)
|
|
{
|
|
dissector_delete ("udp.port", port, tftp_handle);
|
|
}
|
|
|
|
static void range_add_callback (guint32 port)
|
|
{
|
|
dissector_add ("udp.port", port, tftp_handle);
|
|
}
|
|
|
|
void
|
|
proto_reg_handoff_tftp(void)
|
|
{
|
|
static range_t *tftp_port_range;
|
|
static gboolean tftp_initialized = FALSE;
|
|
|
|
if (!tftp_initialized) {
|
|
tftp_handle = find_dissector("tftp");
|
|
heur_dissector_add("stun", dissect_embeddedtftp_heur, proto_tftp);
|
|
tftp_initialized = TRUE;
|
|
} else {
|
|
range_foreach (tftp_port_range, range_delete_callback);
|
|
g_free (tftp_port_range);
|
|
}
|
|
|
|
tftp_port_range = range_copy (global_tftp_port_range);
|
|
range_foreach (tftp_port_range, range_add_callback);
|
|
}
|