forked from osmocom/wireshark
![Ronnie Sahlberg](/assets/img/avatar_default.png)
This is very naughty and will cause problems when we have assigned a dissector to a dynamic port using conversation_set_dissector(). To make ethereal handle this case I have changed the try_conversation_dissector() to allow it to fail and return 0, meaning yes there is indeed a protocol registered for this conversation but that protocol rejected this packet. (which only happens for "new" style dissectors, "old" style dissectors will never reject a packet that way) When this happens the decode_udp_port() helper will still allow other dissectors to be tried, in the hope that the conversation is now used for some other protocol and thus someone else might be able to decode the packet. Update SNMP and TFTP dissectors to check that even if there already is a conversation but that conversation does NOT have snmp/tftp registered as the dissector for it, then create a new conversation anyway and attach the proper dissector. Since ethereal keeps track of which frame number a conversation started in, this actually works really well. svn path=/trunk/; revision=14345
355 lines
9.7 KiB
C
355 lines
9.7 KiB
C
/* packet-tftp.c
|
|
* Routines for tftp packet dissection
|
|
*
|
|
* Richard Sharpe <rsharpe@ns.aus.com>
|
|
* Craig Newell <CraigN@cheque.uq.edu.au>
|
|
* RFC2347 TFTP Option Extension
|
|
*
|
|
* $Id$
|
|
*
|
|
* Ethereal - Network traffic analyzer
|
|
* By Gerald Combs <gerald@ethereal.com>
|
|
* Copyright 1998 Gerald Combs
|
|
*
|
|
* Copied from packet-bootp.c
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version 2
|
|
* of the License, or (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
|
*/
|
|
|
|
#ifdef HAVE_CONFIG_H
|
|
# include "config.h"
|
|
#endif
|
|
|
|
#include <glib.h>
|
|
#include <epan/packet.h>
|
|
#include <epan/conversation.h>
|
|
|
|
static int proto_tftp = -1;
|
|
static int hf_tftp_opcode = -1;
|
|
static int hf_tftp_source_file = -1;
|
|
static int hf_tftp_destination_file = -1;
|
|
static int hf_tftp_transfer_type = -1;
|
|
static int hf_tftp_blocknum = -1;
|
|
static int hf_tftp_error_code = -1;
|
|
static int hf_tftp_error_string = -1;
|
|
|
|
static gint ett_tftp = -1;
|
|
|
|
static dissector_handle_t tftp_handle;
|
|
|
|
#define UDP_PORT_TFTP 69
|
|
|
|
#define TFTP_RRQ 1
|
|
#define TFTP_WRQ 2
|
|
#define TFTP_DATA 3
|
|
#define TFTP_ACK 4
|
|
#define TFTP_ERROR 5
|
|
#define TFTP_OACK 6
|
|
|
|
static const value_string tftp_opcode_vals[] = {
|
|
{ TFTP_RRQ, "Read Request" },
|
|
{ TFTP_WRQ, "Write Request" },
|
|
{ TFTP_DATA, "Data Packet" },
|
|
{ TFTP_ACK, "Acknowledgement" },
|
|
{ TFTP_ERROR, "Error Code" },
|
|
{ TFTP_OACK, "Option Acknowledgement" },
|
|
{ 0, NULL }
|
|
};
|
|
|
|
static const value_string tftp_error_code_vals[] = {
|
|
{ 0, "Not defined" },
|
|
{ 1, "File not found" },
|
|
{ 2, "Access violation" },
|
|
{ 3, "Disk full or allocation exceeded" },
|
|
{ 4, "Illegal TFTP Operation" },
|
|
{ 5, "Unknown transfer ID" },
|
|
{ 6, "File already exists" },
|
|
{ 7, "No such user" },
|
|
{ 8, "Option negotiation failed" },
|
|
{ 0, NULL }
|
|
};
|
|
|
|
static void tftp_dissect_options(tvbuff_t *tvb, int offset, proto_tree *tree);
|
|
|
|
static void
|
|
dissect_tftp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
|
|
{
|
|
proto_tree *tftp_tree = NULL;
|
|
proto_item *ti;
|
|
conversation_t *conversation;
|
|
gint offset = 0;
|
|
guint16 opcode;
|
|
guint16 bytes;
|
|
guint16 blocknum;
|
|
guint i1;
|
|
guint16 error;
|
|
|
|
/*
|
|
* The first TFTP packet goes to the TFTP port; the second one
|
|
* comes from some *other* port, but goes back to the same
|
|
* IP address and port as the ones from which the first packet
|
|
* came; all subsequent packets go between those two IP addresses
|
|
* and ports.
|
|
*
|
|
* If this packet went to the TFTP port, we check to see if
|
|
* there's already a conversation with one address/port pair
|
|
* matching the source IP address and port of this packet,
|
|
* the other address matching the destination IP address of this
|
|
* packet, and any destination port.
|
|
*
|
|
* If not, we create one, with its address 1/port 1 pair being
|
|
* the source address/port of this packet, its address 2 being
|
|
* the destination address of this packet, and its port 2 being
|
|
* wildcarded, and give it the TFTP dissector as a dissector.
|
|
*/
|
|
if (pinfo->destport == UDP_PORT_TFTP) {
|
|
conversation = find_conversation(pinfo->fd->num, &pinfo->src, &pinfo->dst, PT_UDP,
|
|
pinfo->srcport, 0, NO_PORT_B);
|
|
if( (conversation == NULL) || (conversation->dissector_handle!=tftp_handle) ){
|
|
conversation = conversation_new(pinfo->fd->num, &pinfo->src, &pinfo->dst, PT_UDP,
|
|
pinfo->srcport, 0, NO_PORT2);
|
|
conversation_set_dissector(conversation, tftp_handle);
|
|
}
|
|
}
|
|
|
|
if (check_col(pinfo->cinfo, COL_PROTOCOL))
|
|
col_set_str(pinfo->cinfo, COL_PROTOCOL, "TFTP");
|
|
|
|
opcode = tvb_get_ntohs(tvb, offset);
|
|
|
|
if (check_col(pinfo->cinfo, COL_INFO)) {
|
|
|
|
col_add_fstr(pinfo->cinfo, COL_INFO, "%s",
|
|
val_to_str(opcode, tftp_opcode_vals, "Unknown (0x%04x)"));
|
|
|
|
}
|
|
|
|
if (tree) {
|
|
|
|
ti = proto_tree_add_item(tree, proto_tftp, tvb, offset, -1, FALSE);
|
|
tftp_tree = proto_item_add_subtree(ti, ett_tftp);
|
|
|
|
proto_tree_add_uint(tftp_tree, hf_tftp_opcode, tvb,
|
|
offset, 2, opcode);
|
|
}
|
|
offset += 2;
|
|
|
|
switch (opcode) {
|
|
|
|
case TFTP_RRQ:
|
|
i1 = tvb_strsize(tvb, offset);
|
|
if (tree) {
|
|
proto_tree_add_item(tftp_tree, hf_tftp_source_file,
|
|
tvb, offset, i1, FALSE);
|
|
}
|
|
if (check_col(pinfo->cinfo, COL_INFO)) {
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, ", File: %s",
|
|
tvb_get_ptr(tvb, offset, i1));
|
|
}
|
|
offset += i1;
|
|
|
|
i1 = tvb_strsize(tvb, offset);
|
|
if (tree) {
|
|
ti = proto_tree_add_item(tftp_tree, hf_tftp_transfer_type,
|
|
tvb, offset, i1, FALSE);
|
|
}
|
|
if (check_col(pinfo->cinfo, COL_INFO)) {
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, ", Transfer type: %s",
|
|
tvb_get_ptr(tvb, offset, i1));
|
|
}
|
|
offset += i1;
|
|
|
|
if (tree)
|
|
tftp_dissect_options(tvb, offset, tftp_tree);
|
|
break;
|
|
|
|
case TFTP_WRQ:
|
|
i1 = tvb_strsize(tvb, offset);
|
|
if (tree) {
|
|
proto_tree_add_item(tftp_tree, hf_tftp_destination_file,
|
|
tvb, offset, i1, FALSE);
|
|
}
|
|
if (check_col(pinfo->cinfo, COL_INFO)) {
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, ", File: %s",
|
|
tvb_get_ptr(tvb, offset, i1));
|
|
}
|
|
offset += i1;
|
|
|
|
i1 = tvb_strsize(tvb, offset);
|
|
if (tree) {
|
|
ti = proto_tree_add_item(tftp_tree, hf_tftp_transfer_type,
|
|
tvb, offset, i1, FALSE);
|
|
}
|
|
if (check_col(pinfo->cinfo, COL_INFO)) {
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, ", Transfer type: %s",
|
|
tvb_get_ptr(tvb, offset, i1));
|
|
}
|
|
offset += i1;
|
|
|
|
if (tree)
|
|
tftp_dissect_options(tvb, offset, tftp_tree);
|
|
break;
|
|
|
|
case TFTP_DATA:
|
|
blocknum = tvb_get_ntohs(tvb, offset);
|
|
if (tree) {
|
|
proto_tree_add_uint(tftp_tree, hf_tftp_blocknum, tvb, offset, 2,
|
|
blocknum);
|
|
}
|
|
offset += 2;
|
|
|
|
bytes = tvb_reported_length_remaining(tvb, offset);
|
|
|
|
if (check_col(pinfo->cinfo, COL_INFO)) {
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, ", Block: %i%s",
|
|
blocknum,
|
|
(bytes < 512)?" (last)":"" );
|
|
}
|
|
|
|
if (bytes != 0) {
|
|
if (tree) {
|
|
proto_tree_add_text(tftp_tree, tvb, offset, -1,
|
|
"Data (%d bytes)", bytes);
|
|
}
|
|
}
|
|
break;
|
|
|
|
case TFTP_ACK:
|
|
blocknum = tvb_get_ntohs(tvb, offset);
|
|
if (tree) {
|
|
proto_tree_add_uint(tftp_tree, hf_tftp_blocknum, tvb, offset, 2,
|
|
blocknum);
|
|
}
|
|
if (check_col(pinfo->cinfo, COL_INFO)) {
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, ", Block: %i",
|
|
blocknum);
|
|
}
|
|
break;
|
|
|
|
case TFTP_ERROR:
|
|
error = tvb_get_ntohs(tvb, offset);
|
|
if (tree) {
|
|
proto_tree_add_uint(tftp_tree, hf_tftp_error_code, tvb, offset, 2,
|
|
error);
|
|
}
|
|
if (check_col(pinfo->cinfo, COL_INFO)) {
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, ", Code: %s",
|
|
val_to_str(error, tftp_error_code_vals, "Unknown (%u)"));
|
|
}
|
|
offset += 2;
|
|
|
|
i1 = tvb_strsize(tvb, offset);
|
|
if (tree) {
|
|
proto_tree_add_item(tftp_tree, hf_tftp_error_string, tvb, offset,
|
|
i1, FALSE);
|
|
}
|
|
if (check_col(pinfo->cinfo, COL_INFO)) {
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, ", Message: %s",
|
|
tvb_get_ptr(tvb, offset, i1));
|
|
}
|
|
break;
|
|
|
|
case TFTP_OACK:
|
|
if (tree)
|
|
tftp_dissect_options(tvb, offset, tftp_tree);
|
|
break;
|
|
|
|
default:
|
|
if (tree) {
|
|
proto_tree_add_text(tftp_tree, tvb, offset, -1,
|
|
"Data (%d bytes)", tvb_reported_length_remaining(tvb, offset));
|
|
}
|
|
break;
|
|
|
|
}
|
|
}
|
|
|
|
static void
|
|
tftp_dissect_options(tvbuff_t *tvb, int offset, proto_tree *tree)
|
|
{
|
|
int option_len, value_len;
|
|
int value_offset;
|
|
|
|
while (tvb_offset_exists(tvb, offset)) {
|
|
option_len = tvb_strsize(tvb, offset); /* length of option */
|
|
value_offset = offset + option_len;
|
|
value_len = tvb_strsize(tvb, value_offset); /* length of value */
|
|
proto_tree_add_text(tree, tvb, offset, option_len+value_len,
|
|
"Option: %s = %s",
|
|
tvb_get_ptr(tvb, offset, option_len),
|
|
tvb_get_ptr(tvb, value_offset, value_len));
|
|
offset += option_len + value_len;
|
|
}
|
|
}
|
|
|
|
void
|
|
proto_register_tftp(void)
|
|
{
|
|
static hf_register_info hf[] = {
|
|
{ &hf_tftp_opcode,
|
|
{ "Opcode", "tftp.opcode",
|
|
FT_UINT16, BASE_DEC, VALS(tftp_opcode_vals), 0x0,
|
|
"TFTP message type", HFILL }},
|
|
|
|
{ &hf_tftp_source_file,
|
|
{ "Source File", "tftp.source_file",
|
|
FT_STRINGZ, BASE_DEC, NULL, 0x0,
|
|
"TFTP source file name", HFILL }},
|
|
|
|
{ &hf_tftp_destination_file,
|
|
{ "DESTINATION File", "tftp.destination_file",
|
|
FT_STRINGZ, BASE_DEC, NULL, 0x0,
|
|
"TFTP source file name", HFILL }},
|
|
|
|
{ &hf_tftp_transfer_type,
|
|
{ "Type", "tftp.type",
|
|
FT_STRINGZ, BASE_DEC, 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_DEC, NULL, 0x0,
|
|
"Error string in case of TFTP error message", HFILL }}
|
|
};
|
|
static gint *ett[] = {
|
|
&ett_tftp,
|
|
};
|
|
|
|
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);
|
|
}
|
|
|
|
void
|
|
proto_reg_handoff_tftp(void)
|
|
{
|
|
tftp_handle = find_dissector("tftp");
|
|
|
|
dissector_add("udp.port", UDP_PORT_TFTP, tftp_handle);
|
|
}
|