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TECMP: Adding Subdissector support 

Adding subdissector support based on interface_id. This allows to write
custom dissectors for e.g. UART/RS232 data.
This commit is contained in:
Dr. Lars Völker 2022-07-19 23:24:59 +02:00 committed by A Wireshark GitLab Utility
parent d92af30f29
commit 3e7ea95108
3 changed files with 95 additions and 18 deletions
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1
epan/dissectors/CMakeLists.txt
View File

@ -590,6 +590,7 @@ set(DISSECTOR_PUBLIC_HEADERS
packet-tcap.h
packet-tcp.h
packet-tcpcl.h
packet-tecmp.h
packet-tetra.h
packet-thrift.h
packet-tls-utils.h

73
epan/dissectors/packet-tecmp.c
View File

@ -27,6 +27,7 @@
#include <epan/proto_data.h>
#include <wsutil/utf8_entities.h>
#include <packet-tecmp.h>
#include <packet-socketcan.h>
#include <packet-flexray.h>
#include <packet-lin.h>
@ -48,7 +49,8 @@ static gboolean analog_samples_are_signed_int = TRUE;
static dissector_table_t fr_subdissector_table;
static heur_dissector_list_t fr_heur_subdissector_list;
static dissector_table_t lin_subdissector_table;
static dissector_table_t data_subdissector_table;
static dissector_handle_t text_lines_handle;
/* Header fields */
/* TECMP */
@ -1369,9 +1371,35 @@ dissect_tecmp_status_device(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
return offset - offset_orig;
}
static int
dissect_data(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint16 device_id, guint8 msg_type, guint16 data_type, guint32 interface_id) {
tecmp_info_t tecmp_info;
int dissected_bytes;
tecmp_info.interface_id = interface_id;
tecmp_info.device_id = device_id;
tecmp_info.data_type = data_type;
tecmp_info.msg_type = msg_type;
dissector_handle_t handle = dissector_get_uint_handle(data_subdissector_table, interface_id);
if (handle != NULL) {
dissected_bytes = call_dissector_only(handle, tvb, pinfo, tree, &tecmp_info);
if (dissected_bytes > 0) {
return dissected_bytes;
}
}
if (tecmp_info.data_type == TECMP_DATA_TYPE_RS232_ASCII) {
return call_dissector(text_lines_handle, tvb, pinfo, tree);
} else {
return call_data_dissector(tvb, pinfo, tree);
}
}
static int
dissect_tecmp_log_or_replay_stream(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint offset_orig,
guint16 msg_type, guint tecmp_msg_type) {
guint16 data_type, guint8 tecmp_msg_type, guint16 device_id) {
proto_item *ti = NULL;
proto_item *ti_tecmp = NULL;
proto_tree *tecmp_tree = NULL;
@ -1421,10 +1449,10 @@ dissect_tecmp_log_or_replay_stream(tvbuff_t *tvb, packet_info *pinfo, proto_tree
length = tvb_get_guint16(tvb, offset+12, ENC_BIG_ENDIAN);
ti_tecmp = proto_tree_add_item(tree, proto_tecmp_payload, tvb, offset, (gint)length + 16, ENC_NA);
proto_item_append_text(ti_tecmp, " (%s)", val_to_str(msg_type, tecmp_msgtype_names, "Unknown (%d)"));
proto_item_append_text(ti_tecmp, " (%s)", val_to_str(data_type, tecmp_msgtype_names, "Unknown (%d)"));
tecmp_tree = proto_item_add_subtree(ti_tecmp, ett_tecmp_payload);
offset += dissect_tecmp_entry_header(tvb, pinfo, tecmp_tree, offset, tecmp_msg_type, msg_type, first, &dataflags, &interface_id);
offset += dissect_tecmp_entry_header(tvb, pinfo, tecmp_tree, offset, tecmp_msg_type, data_type, first, &dataflags, &interface_id);
first = FALSE;
@ -1432,7 +1460,7 @@ dissect_tecmp_log_or_replay_stream(tvbuff_t *tvb, packet_info *pinfo, proto_tree
sub_tvb = tvb_new_subset_length_caplen(tvb, offset, (gint)length, (gint)length);
offset2 = 0;
switch (msg_type) {
switch (data_type) {
case TECMP_DATA_TYPE_LIN:
lin_info.id = tvb_get_guint8(sub_tvb, offset2) & DATA_LIN_ID_MASK;
@ -1453,7 +1481,7 @@ dissect_tecmp_log_or_replay_stream(tvbuff_t *tvb, packet_info *pinfo, proto_tree
guint32 bus_frame_id = lin_info.id | (lin_info.bus_id << 16);
if (!dissector_try_uint_new(lin_subdissector_table, bus_frame_id, payload_tvb, pinfo, tree, FALSE, &lin_info)) {
if (!dissector_try_uint_new(lin_subdissector_table, lin_info.id, payload_tvb, pinfo, tree, FALSE, &lin_info)) {
call_data_dissector(payload_tvb, pinfo, tree);
dissect_data(payload_tvb, pinfo, tree, device_id, tecmp_msg_type, data_type, interface_id);
}
}
offset2 += (gint)length2;
@ -1485,14 +1513,14 @@ dissect_tecmp_log_or_replay_stream(tvbuff_t *tvb, packet_info *pinfo, proto_tree
payload_tvb = tvb_new_subset_length(sub_tvb, offset2, length2);
offset2 += length2;
can_info.fd = (msg_type == TECMP_DATA_TYPE_CAN_FD_DATA);
can_info.fd = (data_type == TECMP_DATA_TYPE_CAN_FD_DATA);
can_info.len = tvb_captured_length_remaining(sub_tvb, offset2);
can_info.bus_id = ht_interface_config_to_bus_id(interface_id);
/* luckely TECMP and SocketCAN share the first bit as indicator for 11 vs 29bit Identifiers */
can_info.id = tmp;
if (msg_type == TECMP_DATA_TYPE_CAN_DATA && (dataflags & DATA_FLAG_CAN_RTR) == DATA_FLAG_CAN_RTR) {
if (data_type == TECMP_DATA_TYPE_CAN_DATA && (dataflags & DATA_FLAG_CAN_RTR) == DATA_FLAG_CAN_RTR) {
can_info.id |= CAN_RTR_FLAG;
}
@ -1501,14 +1529,14 @@ dissect_tecmp_log_or_replay_stream(tvbuff_t *tvb, packet_info *pinfo, proto_tree
}
if (!socketcan_call_subdissectors(payload_tvb, pinfo, tree, &can_info, heuristic_first)) {
call_data_dissector(payload_tvb, pinfo, tree);
dissect_data(payload_tvb, pinfo, tree, device_id, tecmp_msg_type, data_type, interface_id);
}
}
/* new for TECMP 1.6 */
if (msg_type == TECMP_DATA_TYPE_CAN_DATA && tvb_captured_length_remaining(sub_tvb, offset2) >= 2) {
if (data_type == TECMP_DATA_TYPE_CAN_DATA && tvb_captured_length_remaining(sub_tvb, offset2) >= 2) {
proto_tree_add_item(tecmp_tree, hf_tecmp_payload_data_crc15, sub_tvb, offset2, 2, ENC_BIG_ENDIAN);
} else if (msg_type == TECMP_DATA_TYPE_CAN_FD_DATA && tvb_captured_length_remaining(sub_tvb, offset2) >= 3) {
} else if (data_type == TECMP_DATA_TYPE_CAN_FD_DATA && tvb_captured_length_remaining(sub_tvb, offset2) >= 3) {
if (length2 <= 16) {
proto_tree_add_item(tecmp_tree, hf_tecmp_payload_data_crc17, sub_tvb, offset2, 3, ENC_BIG_ENDIAN);
} else {
@ -1543,7 +1571,7 @@ dissect_tecmp_log_or_replay_stream(tvbuff_t *tvb, packet_info *pinfo, proto_tree
offset2 += length2;
if (!flexray_call_subdissectors(payload_tvb, pinfo, tree, &fr_info, heuristic_first)) {
call_data_dissector(payload_tvb, pinfo, tree);
dissect_data(payload_tvb, pinfo, tree, device_id, tecmp_msg_type, data_type, interface_id);
}
}
@ -1560,7 +1588,7 @@ dissect_tecmp_log_or_replay_stream(tvbuff_t *tvb, packet_info *pinfo, proto_tree
break;
case TECMP_DATA_TYPE_RS232_ASCII:
call_data_dissector(sub_tvb, pinfo, tree);
dissect_data(sub_tvb, pinfo, tree, device_id, tecmp_msg_type, data_type, interface_id);
break;
case TECMP_DATA_TYPE_ANALOG:
@ -1631,7 +1659,7 @@ dissect_tecmp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U
proto_tree *tecmp_tree = NULL;
guint offset = 0;
guint tecmp_type = 0;
guint tecmp_msg_type = 0;
guint data_type = 0;
guint device_id = 0;
static int * const tecmp_flags[] = {
@ -1665,7 +1693,7 @@ dissect_tecmp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U
proto_tree_add_item_ret_uint(tecmp_tree, hf_tecmp_msgtype, tvb, offset, 1, ENC_NA, &tecmp_type);
offset += 1;
proto_tree_add_item_ret_uint(tecmp_tree, hf_tecmp_data_type, tvb, offset, 2, ENC_BIG_ENDIAN, &tecmp_msg_type);
proto_tree_add_item_ret_uint(tecmp_tree, hf_tecmp_data_type, tvb, offset, 2, ENC_BIG_ENDIAN, &data_type);
offset += 2;
proto_tree_add_item(tecmp_tree, hf_tecmp_res, tvb, offset, 2, ENC_BIG_ENDIAN);
@ -1677,18 +1705,18 @@ dissect_tecmp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U
switch (tecmp_type) {
case TECMP_MSG_TYPE_CTRL_MSG:
offset += dissect_tecmp_control_msg(tvb, pinfo, tree, offset, (guint16)tecmp_msg_type, (guint8)tecmp_type);
offset += dissect_tecmp_control_msg(tvb, pinfo, tree, offset, (guint16)data_type, (guint8)tecmp_type);
break;
case TECMP_MSG_TYPE_STATUS_BUS:
case TECMP_MSG_TYPE_CFG_CM:
case TECMP_MSG_TYPE_STATUS_DEV:
offset += dissect_tecmp_status_device(tvb, pinfo, tree, offset, (guint16)tecmp_msg_type, (guint8)tecmp_type);
offset += dissect_tecmp_status_device(tvb, pinfo, tree, offset, (guint16)data_type, (guint8)tecmp_type);
break;
case TECMP_MSG_TYPE_LOG_STREAM:
case TECMP_MSG_TYPE_REPLAY_DATA:
offset += dissect_tecmp_log_or_replay_stream(tvb, pinfo, tree, offset, (guint16)tecmp_msg_type, (guint8)tecmp_type);
offset += dissect_tecmp_log_or_replay_stream(tvb, pinfo, tree, offset, (guint16)data_type, (guint8)tecmp_type, (guint16)device_id);
break;
}
@ -2102,6 +2130,13 @@ proto_register_tecmp_payload(void) {
proto_register_subtree_array(ett, array_length(ett));
expert_module_tecmp_payload = expert_register_protocol(proto_tecmp_payload);
expert_register_field_array(expert_module_tecmp_payload, ei, array_length(ei));
/*
* Dissectors can register themselves in this table.
*/
data_subdissector_table = register_dissector_table(TECMP_PAYLOAD_INTERFACE_ID, "TECMP Interface ID", proto_tecmp_payload, FT_UINT32, BASE_HEX);
}
void
@ -2267,6 +2302,8 @@ proto_reg_handoff_tecmp(void) {
fr_heur_subdissector_list = find_heur_dissector_list("flexray");
lin_subdissector_table = find_dissector_table("lin.frame_id");
text_lines_handle = find_dissector_add_dependency("data-text-lines", proto_tecmp);
}
/*

39
epan/dissectors/packet-tecmp.h Normal file
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@ -0,0 +1,39 @@
/* packet-tecmp.h
*
* Definitions for TECMP
* By Dr. Lars Voelker <lars.voelker@technica-engineering.de>
* Copyright 2022-2022 Dr. Lars Voelker
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#ifndef __PACKET_TECMP_H__
#define __PACKET_TECMP_H__
#define TECMP_PAYLOAD_INTERFACE_ID "tecmp.payload.interface_id"
typedef struct tecmp_info {
guint32 interface_id;
guint16 device_id;
guint16 data_type;
guint8 msg_type;
} tecmp_info_t;
#endif /* __PACKET_TECMP_H__ */
/*
* Editor modelines
*
* Local Variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* ex: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/