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wireshark/epan/dissectors/packet-dji-uav.c
Michael Mann 268841f3e0 Combine Decode As and port preferences for tcp.port dissector table. 
This patch introduces new APIs to allow dissectors to have a preference for
a (TCP) port, but the underlying data is actually part of Decode As functionality.
For now the APIs are intentionally separate from the regular APIs that register a
dissector within a dissector table.  It may be possible to eventually combine the
two so that all dissectors that register with a dissector table have an opportunity
to "automatically" have a preference to adjust the "table value" through the
preferences dialog.

The tcp.port dissector table was used as the guinea pig.  This will eventually be
expanded to other dissector tables as well (most notably UDP ports).  Some
dissectors that "shared" a TCP/UDP port preference were also converted. It also
removed the need for some preference callback functions (mostly when the callback
function was the proto_reg_handoff function) so there is cleanup around that.

Dissectors that has a port preference whose default was 0 were switched to using
the dissector_add_for_decode_as_with_preference API rather than dissector_add_uint_with_preference

Also added comments for TCP ports used that aren't IANA registered.

Change-Id: I99604f95d426ad345f4b494598d94178b886eb67
Reviewed-on: https://code.wireshark.org/review/17724
Reviewed-by: Michael Mann <mmann78@netscape.net>
2016-10-08 02:44:53 +00:00

405 lines
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/* packet-dji-uav.c
* Routines for the disassembly of the command protocol for the
* DJI Phantom 2 Vision+ UAV
* http://www.dji.com/product/phantom-2-vision-plus
* and possibly others.
*
* Copyright 2014,2015 Joerg Mayer (see AUTHORS file)
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/*
*/
#include "config.h"
#include <glib.h>
#include <epan/packet.h>
/* TCP desegmentation */
#include "packet-tcp.h"
/* Request Response tracking */
#include <epan/conversation.h>
#include <epan/prefs.h>
void proto_register_djiuav(void);
void proto_reg_handoff_djiuav(void);
/* Enable desegmentation of djiuav over TCP */
static gboolean djiuav_desegment = TRUE;
/* Command/Response tracking */
typedef struct _djiuav_conv_info_t {
wmem_map_t *pdus;
} djiuav_conv_info_t;
typedef struct _djiuav_transaction_t {
guint16 seqno;
guint8 command;
guint32 request_frame;
guint32 reply_frame;
nstime_t request_time;
} djiuav_transaction_t;
/* Finally: Protocol specific stuff */
/* protocol handles */
static int proto_djiuav = -1;
/* ett handles */
static int ett_djiuav = -1;
/* hf elements */
static int hf_djiuav_magic = -1;
static int hf_djiuav_length = -1;
static int hf_djiuav_flags = -1;
static int hf_djiuav_seqno = -1;
static int hf_djiuav_cmd = -1;
static int hf_djiuav_checksum = -1;
#if 0
static int hf_djiuav_cmd04_unknown = -1;
static int hf_djiuav_resp04_unknown = -1;
#endif
static int hf_djiuav_cmd20_unknown = -1;
#if 0
static int hf_djiuav_resp20_unknown = -1;
#endif
static int hf_djiuav_cmdunk = -1;
static int hf_djiuav_respunk = -1;
static int hf_djiuav_extradata = -1;
/* hf request/response tracking */
static int hf_djiuav_response_in = -1;
static int hf_djiuav_response_to = -1;
static int hf_djiuav_response_time = -1;
#define PROTO_SHORT_NAME "DJIUAV"
#define PROTO_LONG_NAME "DJI UAV Drone Control Protocol"
#define PORT_DJIUAV 2001 /* Not IANA registered */
static const value_string djiuav_pdu_type[] = {
{ 0x20, "Set Time" },
{ 0, NULL }
};
static void
request_response_handling(tvbuff_t *tvb, packet_info *pinfo, proto_tree *djiuav_tree,
guint32 offset)
{
conversation_t *conversation;
djiuav_conv_info_t *djiuav_info;
djiuav_transaction_t *djiuav_trans;
guint16 seq_no;
gboolean is_cmd;
guint8 packet_type;
is_cmd = (pinfo->match_uint == pinfo->destport);
seq_no = tvb_get_letohs(tvb, offset + 4);
packet_type = tvb_get_guint8(tvb, offset + 6);
conversation = find_or_create_conversation(pinfo);
djiuav_info = (djiuav_conv_info_t *)conversation_get_proto_data(conversation, proto_djiuav);
if (!djiuav_info) {
djiuav_info = wmem_new(wmem_file_scope(), djiuav_conv_info_t);
djiuav_info->pdus=wmem_map_new(wmem_file_scope(), g_direct_hash, g_direct_equal);
conversation_add_proto_data(conversation, proto_djiuav, djiuav_info);
}
if (!pinfo->fd->flags.visited) {
if (is_cmd) {
djiuav_trans=wmem_new(wmem_file_scope(), djiuav_transaction_t);
djiuav_trans->request_frame=pinfo->num;
djiuav_trans->reply_frame=0;
djiuav_trans->request_time=pinfo->abs_ts;
djiuav_trans->seqno=seq_no;
djiuav_trans->command=packet_type;
wmem_map_insert(djiuav_info->pdus, GUINT_TO_POINTER((guint)seq_no), (void *)djiuav_trans);
} else {
djiuav_trans=(djiuav_transaction_t *)wmem_map_lookup(djiuav_info->pdus, GUINT_TO_POINTER((guint)seq_no));
if (djiuav_trans) {
/* Special case: djiuav seems to send 0x24 replies with seqno 0 and without a request */
if (djiuav_trans->reply_frame == 0)
djiuav_trans->reply_frame=pinfo->num;
}
}
} else {
djiuav_trans=(djiuav_transaction_t *)wmem_map_lookup(djiuav_info->pdus, GUINT_TO_POINTER((guint)seq_no));
}
/* djiuav_trans may be 0 in case it's a reply without a matching request */
if (djiuav_tree && djiuav_trans) {
if (is_cmd) {
if (djiuav_trans->reply_frame) {
proto_item *it;
it = proto_tree_add_uint(djiuav_tree, hf_djiuav_response_in,
tvb, 0, 0, djiuav_trans->reply_frame);
PROTO_ITEM_SET_GENERATED(it);
}
} else {
if (djiuav_trans->request_frame) {
proto_item *it;
nstime_t ns;
it = proto_tree_add_uint(djiuav_tree, hf_djiuav_response_to,
tvb, 0, 0, djiuav_trans->request_frame);
PROTO_ITEM_SET_GENERATED(it);
nstime_delta(&ns, &pinfo->abs_ts, &djiuav_trans->request_time);
it = proto_tree_add_time(djiuav_tree, hf_djiuav_response_time, tvb, 0, 0, &ns);
PROTO_ITEM_SET_GENERATED(it);
}
}
}
}
static int
dissect_djiuav_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
proto_item *ti;
proto_tree *djiuav_tree = NULL;
guint32 offset = 0;
guint32 pdu_length;
guint8 packet_type;
gboolean is_cmd;
is_cmd = (pinfo->match_uint == pinfo->destport);
packet_type = tvb_get_guint8(tvb, 6);
col_set_str(pinfo->cinfo, COL_PROTOCOL, PROTO_SHORT_NAME);
col_add_str(pinfo->cinfo, COL_INFO, is_cmd?"C: ":"R: ");
col_append_str(pinfo->cinfo, COL_INFO, val_to_str(packet_type,
djiuav_pdu_type, "Type 0x%02x"));
ti = proto_tree_add_item(tree, proto_djiuav, tvb, offset, -1, ENC_NA);
djiuav_tree = proto_item_add_subtree(ti, ett_djiuav);
request_response_handling(tvb, pinfo, djiuav_tree, offset);
if (tree) {
proto_tree_add_item(djiuav_tree, hf_djiuav_magic, tvb, offset, 2,
ENC_BIG_ENDIAN);
offset += 2;
pdu_length = tvb_get_guint8(tvb, offset);
proto_tree_add_item(djiuav_tree, hf_djiuav_length, tvb, offset, 1,
ENC_NA);
offset += 1;
proto_tree_add_item(djiuav_tree, hf_djiuav_flags, tvb, offset, 1,
ENC_NA);
offset += 1;
proto_tree_add_item(djiuav_tree, hf_djiuav_seqno, tvb, offset, 2,
ENC_LITTLE_ENDIAN);
offset += 2;
proto_tree_add_item(djiuav_tree, hf_djiuav_cmd, tvb, offset, 1,
ENC_NA);
offset += 1;
if (is_cmd) { /* Command */
switch (packet_type) {
case 0x20: /* Set time */
/* FIXME: Properly decode this: year(lo) year(hi) month date hour minute second */
proto_tree_add_item(djiuav_tree, hf_djiuav_cmd20_unknown, tvb, offset, 7,
ENC_NA);
offset += 7;
break;
default:
proto_tree_add_item(djiuav_tree, hf_djiuav_cmdunk, tvb, offset, pdu_length - 8,
ENC_NA);
offset += (pdu_length - 8);
break;
}
} else { /* Response */
switch (packet_type) {
default:
proto_tree_add_item(djiuav_tree, hf_djiuav_respunk, tvb,
offset, pdu_length - 8, ENC_NA);
offset += (pdu_length - 8);
break;
}
}
if (offset < pdu_length - 1) { /* We guessed wrong about the cmd len */
proto_tree_add_item(djiuav_tree, hf_djiuav_extradata, tvb, offset,
pdu_length - 1 - offset, ENC_NA);
offset += pdu_length - 1 - offset;
}
/* FIXME: calculate XOR and validate transmitted value */
proto_tree_add_checksum(djiuav_tree, tvb, offset, hf_djiuav_checksum, -1, NULL, pinfo, 0, ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS);
offset += 1;
}
return offset;
}
static gboolean
test_djiuav(tvbuff_t *tvb)
{
/* Minimum of 8 bytes, beginning with magic bytes 0x55BB */
if ( tvb_captured_length(tvb) < 8 /* Size of a command with empty data is at least 8 */
|| tvb_get_ntohs(tvb, 0) != 0x55BB
) {
return FALSE;
}
return TRUE;
}
/* Get the length of the full pdu */
static guint
get_djiuav_pdu_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset, void *data _U_)
{
return tvb_get_guint8(tvb, offset + 2);
}
static int
dissect_djiuav_static(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
{
if ( !test_djiuav(tvb) ) {
return 0;
}
tcp_dissect_pdus(tvb, pinfo, tree, djiuav_desegment, 8,
get_djiuav_pdu_len, dissect_djiuav_pdu, data);
return tvb_captured_length(tvb);
}
void
proto_register_djiuav(void)
{
static hf_register_info hf[] = {
/* DJIUAV header */
{ &hf_djiuav_magic,
{ "Protocol Magic", "djiuav.magic", FT_UINT16, BASE_HEX, NULL,
0x0, NULL, HFILL }},
{ &hf_djiuav_length,
{ "PDU Length", "djiuav.length", FT_UINT8, BASE_HEX, NULL,
0x0, NULL, HFILL }},
{ &hf_djiuav_flags,
{ "Flags", "djiuav.flags", FT_UINT8, BASE_HEX, NULL,
0x0, NULL, HFILL }},
{ &hf_djiuav_seqno,
{ "Sequence No", "djiuav.seqno", FT_UINT16, BASE_DEC, NULL,
0x0, NULL, HFILL }},
{ &hf_djiuav_cmd,
{ "PDU Type", "djiuav.pdutype", FT_UINT8, BASE_HEX, VALS(djiuav_pdu_type),
0x0, NULL, HFILL }},
{ &hf_djiuav_checksum,
{ "Checksum", "djiuav.checksum", FT_UINT8, BASE_HEX, NULL,
0x0, NULL, HFILL }},
/* 0x04 */
#if 0
{ &hf_djiuav_cmd04_unknown,
{ "C04 Unknown", "djiuav.cmd04.unknown", FT_UINT8, BASE_HEX, NULL,
0x0, NULL, HFILL }},
{ &hf_djiuav_resp04_unknown,
{ "R04 Unknown", "djiuav.resp04.unknown", FT_UINT8, BASE_HEX, NULL,
0x0, NULL, HFILL }},
#endif
/* Set time */
{ &hf_djiuav_cmd20_unknown,
{ "Time in BCD", "djiuav.cmd04.bcdtime", FT_BYTES, BASE_NONE, NULL,
0x0, NULL, HFILL }},
#if 0
{ &hf_djiuav_resp20_unknown,
{ "R20 Unknown", "djiuav.resp04.unknown", FT_UINT8, BASE_HEX, NULL,
0x0, NULL, HFILL }},
#endif
/* CMD Unknown */
{ &hf_djiuav_cmdunk,
{ "C Unknown", "djiuav.cmd.unknown", FT_BYTES, BASE_NONE, NULL,
0x0, NULL, HFILL }},
/* RESP Unknown */
{ &hf_djiuav_respunk,
{ "R Unknown", "djiuav.resp.unknown", FT_BYTES, BASE_NONE, NULL,
0x0, NULL, HFILL }},
/* Extra Data (unexpected) */
{ &hf_djiuav_extradata,
{ "Unexpected", "djiuav.unexpected", FT_BYTES, BASE_NONE, NULL,
0x0, NULL, HFILL }},
/* Request - Response tracking */
{ &hf_djiuav_response_in,
{ "Response In", "djiuav.response_in", FT_FRAMENUM, BASE_NONE, NULL,
0x0, "Matching response in frame", HFILL }},
{ &hf_djiuav_response_to,
{ "Request In", "djiuav.response_to",
FT_FRAMENUM, BASE_NONE, NULL,
0x0, "Matching command in frame", HFILL }},
{ &hf_djiuav_response_time,
{ "Response Time", "djiuav.response_time",
FT_RELATIVE_TIME, BASE_NONE, NULL,
0x0, "Time between Command and matching Response", HFILL }},
};
static gint *ett[] = {
&ett_djiuav,
};
module_t *djiuav_module;
proto_djiuav = proto_register_protocol(PROTO_LONG_NAME, PROTO_SHORT_NAME, "djiuav");
proto_register_field_array(proto_djiuav, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
/* Preferences */
djiuav_module = prefs_register_protocol(proto_djiuav, NULL);
prefs_register_bool_preference(djiuav_module, "desegment",
"Reassemble DJIUAV messages",
"Whether DJIUAV should reassemble messages spanning multiple"
" TCP segments (required to get useful results)",
&djiuav_desegment);
}
void
proto_reg_handoff_djiuav(void)
{
dissector_handle_t djiuav_handle;
djiuav_handle = create_dissector_handle(dissect_djiuav_static, proto_djiuav);
dissector_add_uint_with_preference("tcp.port", PORT_DJIUAV, djiuav_handle);
}
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 8
* tab-width: 8
* indent-tabs-mode: t
* End:
*
* vi: set shiftwidth=8 tabstop=8 noexpandtab:
* :indentSize=8:tabSize=8:noTabs=false:
*/
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