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wireshark/epan/dissectors/packet-lin.c

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/* packet-lin.c
*
* LIN dissector.
* By Dr. Lars Voelker <lars.voelker@technica-engineering.de>
* Copyright 2021-2021 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
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/decode_as.h>
#include <epan/prefs.h>
#include <wiretap/wtap.h>
#include <epan/expert.h>
#include <epan/uat.h>
#include <packet-lin.h>
/*
* Dissector for the Local Interconnect Network (LIN) bus.
*
* see ISO 17987 or search for "LIN Specification 2.2a" online.
*/
#define LIN_NAME "LIN"
#define LIN_NAME_LONG "LIN Protocol"
#define LIN_NAME_FILTER "lin"
static heur_dissector_list_t heur_subdissector_list;
static heur_dtbl_entry_t *heur_dtbl_entry;
static int proto_lin = -1;
/* header field */
static int hf_lin_msg_format_rev = -1;
static int hf_lin_reserved1 = -1;
static int hf_lin_payload_length = -1;
static int hf_lin_message_type = -1;
static int hf_lin_checksum_type = -1;
static int hf_lin_pid = -1;
static int hf_lin_id = -1;
static int hf_lin_parity = -1;
static int hf_lin_checksum = -1;
static int hf_lin_err_errors = -1;
static int hf_lin_err_no_slave_response = -1;
static int hf_lin_err_framing = -1;
static int hf_lin_err_parity = -1;
static int hf_lin_err_checksum = -1;
static int hf_lin_err_invalidid = -1;
static int hf_lin_err_overflow = -1;
static int hf_lin_event_id = -1;
static gint ett_lin = -1;
static gint ett_lin_pid = -1;
static gint ett_errors = -1;
static int * const error_fields[] = {
&hf_lin_err_overflow,
&hf_lin_err_invalidid,
&hf_lin_err_checksum,
&hf_lin_err_parity,
&hf_lin_err_framing,
&hf_lin_err_no_slave_response,
NULL
};
static dissector_table_t subdissector_table;
#define LIN_MSG_TYPE_FRAME 0
#define LIN_MSG_TYPE_EVENT 3
static const value_string lin_msg_type_names[] = {
{ LIN_MSG_TYPE_FRAME, "Frame" },
{ LIN_MSG_TYPE_EVENT, "Event" },
{0, NULL}
};
#define LIN_CHKSUM_TYPE_UNKN_ERR 0
#define LIN_CHKSUM_TYPE_CLASSIC 1
#define LIN_CHKSUM_TYPE_ENHANCED 2
#define LIN_CHKSUM_TYPE_UNDEF 3
static const value_string lin_checksum_type_names[] = {
{ LIN_CHKSUM_TYPE_UNKN_ERR, "Unknown/Error" },
{ LIN_CHKSUM_TYPE_CLASSIC, "Classic" },
{ LIN_CHKSUM_TYPE_ENHANCED, "Enhanced" },
{ LIN_CHKSUM_TYPE_UNDEF, "Undefined" },
{0, NULL}
};
#define LIN_EVENT_TYPE_GO_TO_SLEEP_EVENT_BY_GO_TO_SLEEP 0xB0B00001
#define LIN_EVENT_TYPE_GO_TO_SLEEP_EVENT_BY_INACTIVITY 0xB0B00002
#define LIN_EVENT_TYPE_WAKE_UP_BY_WAKE_UP_SIGNAL 0xB0B00004
static const value_string lin_event_type_names[] = {
{ LIN_EVENT_TYPE_GO_TO_SLEEP_EVENT_BY_GO_TO_SLEEP, "Go-to-Sleep event by Go-to-Sleep frame" },
{ LIN_EVENT_TYPE_GO_TO_SLEEP_EVENT_BY_INACTIVITY, "Go-to-Sleep event by Inactivity for more than 4s" },
{ LIN_EVENT_TYPE_WAKE_UP_BY_WAKE_UP_SIGNAL, "Wake-up event by Wake-up signal" },
{0, NULL}
};
void proto_reg_handoff_lin(void);
void proto_register_lin(void);
/********* UATs *********/
/* Interface Config UAT */
typedef struct _interface_config {
guint interface_id;
gchar *interface_name;
guint bus_id;
} interface_config_t;
#define DATAFILE_LIN_INTERFACE_MAPPING "LIN_interface_mapping"
static GHashTable *data_lin_interfaces_by_id = NULL;
static GHashTable *data_lin_interfaces_by_name = NULL;
static interface_config_t* interface_configs = NULL;
static guint interface_config_num = 0;
UAT_HEX_CB_DEF(interface_configs, interface_id, interface_config_t)
UAT_CSTRING_CB_DEF(interface_configs, interface_name, interface_config_t)
UAT_HEX_CB_DEF(interface_configs, bus_id, interface_config_t)
static void *
copy_interface_config_cb(void *n, const void *o, size_t size _U_) {
interface_config_t *new_rec = (interface_config_t *)n;
const interface_config_t *old_rec = (const interface_config_t *)o;
new_rec->interface_id = old_rec->interface_id;
new_rec->interface_name = g_strdup(old_rec->interface_name);
new_rec->bus_id = old_rec->bus_id;
return new_rec;
}
static gboolean
update_interface_config(void *r, char **err) {
interface_config_t *rec = (interface_config_t *)r;
if (rec->interface_id > 0xffffffff) {
*err = ws_strdup_printf("We currently only support 32 bit identifiers (ID: %i Name: %s)",
rec->interface_id, rec->interface_name);
return FALSE;
}
if (rec->bus_id > 0xffff) {
*err = ws_strdup_printf("We currently only support 16 bit bus identifiers (ID: %i Name: %s Bus-ID: %i)",
rec->interface_id, rec->interface_name, rec->bus_id);
return FALSE;
}
return TRUE;
}
static void
free_interface_config_cb(void *r) {
interface_config_t *rec = (interface_config_t *)r;
/* freeing result of g_strdup */
g_free(rec->interface_name);
rec->interface_name = NULL;
}
static interface_config_t *
ht_lookup_interface_config_by_id(unsigned int identifier) {
interface_config_t *tmp = NULL;
unsigned int *id = NULL;
if (interface_configs == NULL) {
return NULL;
}
id = wmem_new(wmem_epan_scope(), unsigned int);
*id = (unsigned int)identifier;
tmp = (interface_config_t *)g_hash_table_lookup(data_lin_interfaces_by_id, id);
wmem_free(wmem_epan_scope(), id);
return tmp;
}
static interface_config_t *
ht_lookup_interface_config_by_name(const gchar *name) {
interface_config_t *tmp = NULL;
gchar *key = NULL;
if (interface_configs == NULL) {
return NULL;
}
key = wmem_strdup(wmem_epan_scope(), name);
tmp = (interface_config_t *)g_hash_table_lookup(data_lin_interfaces_by_name, key);
wmem_free(wmem_epan_scope(), key);
return tmp;
}
static void
lin_free_key(gpointer key) {
wmem_free(wmem_epan_scope(), key);
}
static void
post_update_lin_interfaces_cb(void) {
guint i;
int *key_id = NULL;
gchar *key_name = NULL;
/* destroy old hash tables, if they exist */
if (data_lin_interfaces_by_id) {
g_hash_table_destroy(data_lin_interfaces_by_id);
data_lin_interfaces_by_id = NULL;
}
if (data_lin_interfaces_by_name) {
g_hash_table_destroy(data_lin_interfaces_by_name);
data_lin_interfaces_by_name = NULL;
}
/* create new hash table */
data_lin_interfaces_by_id = g_hash_table_new_full(g_int_hash, g_int_equal, &lin_free_key, NULL);
data_lin_interfaces_by_name = g_hash_table_new_full(g_str_hash, g_str_equal, &lin_free_key, NULL);
if (data_lin_interfaces_by_id == NULL || data_lin_interfaces_by_name == NULL || interface_configs == NULL || interface_config_num == 0) {
return;
}
for (i = 0; i < interface_config_num; i++) {
if (interface_configs[i].interface_id != 0xfffffff) {
key_id = wmem_new(wmem_epan_scope(), int);
*key_id = interface_configs[i].interface_id;
g_hash_table_insert(data_lin_interfaces_by_id, key_id, &interface_configs[i]);
}
if (interface_configs[i].interface_name != NULL && interface_configs[i].interface_name[0] != 0) {
key_name = wmem_strdup(wmem_epan_scope(), interface_configs[i].interface_name);
g_hash_table_insert(data_lin_interfaces_by_name, key_name, &interface_configs[i]);
}
}
}
/* We match based on the config in the following order:
* - interface_name matches and interface_id matches
* - interface_name matches and interface_id = 0xffffffff
* - interface_name = "" and interface_id matches
*/
static guint
get_bus_id(packet_info *pinfo) {
guint32 interface_id = pinfo->rec->rec_header.packet_header.interface_id;
const char *interface_name = epan_get_interface_name(pinfo->epan, interface_id);
interface_config_t *tmp = NULL;
if (!(pinfo->rec->presence_flags & WTAP_HAS_INTERFACE_ID)) {
return 0;
}
if (interface_name != NULL && interface_name[0] != 0) {
tmp = ht_lookup_interface_config_by_name(interface_name);
if (tmp != NULL && (tmp->interface_id == 0xffffffff || tmp->interface_id == interface_id)) {
/* name + id match or name match and id = any */
return tmp->bus_id;
}
tmp = ht_lookup_interface_config_by_id(interface_id);
if (tmp != NULL && (tmp->interface_name == NULL || tmp->interface_name[0] == 0)) {
/* id matches and name is any */
return tmp->bus_id;
}
}
/* we found nothing */
return 0;
}
static int
dissect_lin(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_) {
proto_item *ti;
proto_item *ti_root;
proto_tree *lin_tree;
proto_tree *lin_id_tree;
tvbuff_t *next_tvb;
guint payload_length;
guint msg_type;
lin_info_t lininfo;
col_set_str(pinfo->cinfo, COL_PROTOCOL, LIN_NAME);
col_clear(pinfo->cinfo, COL_INFO);
ti_root = proto_tree_add_item(tree, proto_lin, tvb, 0, -1, ENC_NA);
lin_tree = proto_item_add_subtree(ti_root, ett_lin);
proto_tree_add_item(lin_tree, hf_lin_msg_format_rev, tvb, 0, 1, ENC_BIG_ENDIAN);
ti = proto_tree_add_item(lin_tree, hf_lin_reserved1, tvb, 1, 3, ENC_BIG_ENDIAN);
proto_item_set_hidden(ti);
proto_tree_add_item_ret_uint(lin_tree, hf_lin_payload_length, tvb, 4, 1, ENC_BIG_ENDIAN, &payload_length);
proto_tree_add_item_ret_uint(lin_tree, hf_lin_message_type, tvb, 4, 1, ENC_BIG_ENDIAN, &msg_type);
if (msg_type != LIN_MSG_TYPE_EVENT) {
proto_tree_add_item(lin_tree, hf_lin_checksum_type, tvb, 4, 1, ENC_BIG_ENDIAN);
ti = proto_tree_add_item(lin_tree, hf_lin_pid, tvb, 5, 1, ENC_BIG_ENDIAN);
lin_id_tree = proto_item_add_subtree(ti, ett_lin_pid);
proto_tree_add_item(lin_id_tree, hf_lin_parity, tvb, 5, 1, ENC_BIG_ENDIAN);
proto_tree_add_item_ret_uint(lin_id_tree, hf_lin_id, tvb, 5, 1, ENC_BIG_ENDIAN, &(lininfo.id));
proto_tree_add_item(lin_tree, hf_lin_checksum, tvb, 6, 1, ENC_BIG_ENDIAN);
}
proto_tree_add_bitmask(lin_tree, tvb, 7, hf_lin_err_errors, ett_errors, error_fields, ENC_BIG_ENDIAN);
col_add_fstr(pinfo->cinfo, COL_INFO, "LIN %s", val_to_str(msg_type, lin_msg_type_names, "(0x%02x)"));
switch (msg_type) {
case LIN_MSG_TYPE_EVENT: {
guint event_id;
proto_tree_add_item_ret_uint(lin_tree, hf_lin_event_id, tvb, 8, 4, ENC_BIG_ENDIAN, &event_id);
col_append_fstr(pinfo->cinfo, COL_INFO, ": %s", val_to_str(event_id, lin_event_type_names, "0x%08x"));
proto_item_set_end(ti_root, tvb, 12);
return 12; /* 8 Byte header + 4 Byte payload */
}
break;
case LIN_MSG_TYPE_FRAME:
if (payload_length > 0) {
next_tvb = tvb_new_subset_length(tvb, 8, payload_length);
proto_item_set_end(ti_root, tvb, 8 + payload_length);
lininfo.len = (guint16)payload_length;
lininfo.bus_id = (guint16)get_bus_id(pinfo);
guint32 bus_frame_id = lininfo.id | (lininfo.bus_id << 16);
if (!dissector_try_uint_new(subdissector_table, bus_frame_id, next_tvb, pinfo, tree, TRUE, &lininfo)) {
if (!dissector_try_uint_new(subdissector_table, lininfo.id, next_tvb, pinfo, tree, TRUE, &lininfo)) {
if (!dissector_try_heuristic(heur_subdissector_list, next_tvb, pinfo, tree, &heur_dtbl_entry, &lininfo)) {
call_data_dissector(next_tvb, pinfo, tree);
}
}
}
}
break;
}
/* format pads to 4 bytes*/
if (payload_length <= 4) {
proto_item_set_end(ti_root, tvb, 12);
return 12;
} else if (payload_length <= 8) {
proto_item_set_end(ti_root, tvb, 16);
return 16;
} else {
return tvb_captured_length(tvb);
}
}
void
proto_register_lin(void) {
module_t *lin_module;
uat_t *lin_interface_uat = NULL;
static hf_register_info hf[] = {
{ &hf_lin_msg_format_rev,
{ "Message Format Revision", "lin.message_format",
FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},
{ &hf_lin_reserved1,
{ "Reserved", "lin.reserved",
FT_UINT24, BASE_HEX, NULL, 0x0, NULL, HFILL }},
{ &hf_lin_payload_length,
{ "Length", "lin.length",
FT_UINT8, BASE_DEC, NULL, 0xf0, NULL, HFILL }},
{ &hf_lin_message_type,
{ "Message Type", "lin.message_type",
FT_UINT8, BASE_DEC, VALS(lin_msg_type_names), 0x0c, NULL, HFILL }},
{ &hf_lin_checksum_type,
{ "Checksum Type", "lin.checksum_type",
FT_UINT8, BASE_DEC, VALS(lin_checksum_type_names), 0x03, NULL, HFILL }},
{ &hf_lin_pid,
{ "Protected ID", "lin.protected_id",
FT_UINT8, BASE_HEX_DEC, NULL, 0x00, NULL, HFILL }},
{ &hf_lin_id,
{ "Frame ID", "lin.frame_id",
FT_UINT8, BASE_HEX_DEC, NULL, 0x3f, NULL, HFILL }},
{ &hf_lin_parity,
{ "Parity", "lin.frame_parity",
FT_UINT8, BASE_HEX_DEC, NULL, 0xc0, NULL, HFILL }},
{ &hf_lin_checksum,
{ "Checksum", "lin.checksum",
FT_UINT8, BASE_HEX, NULL, 0x00, NULL, HFILL }},
{ &hf_lin_err_errors,
{ "Errors", "lin.errors",
FT_UINT8, BASE_HEX, NULL, 0x00, NULL, HFILL }},
{ &hf_lin_err_no_slave_response,
{ "No Slave Response Error", "lin.errors.no_slave_response",
FT_BOOLEAN, 8, NULL, 0x01, NULL, HFILL }},
{ &hf_lin_err_framing,
{ "Framing Error", "lin.errors.framing_error",
FT_BOOLEAN, 8, NULL, 0x02, NULL, HFILL }},
{ &hf_lin_err_parity,
{ "Parity Error", "lin.errors.parity_error",
FT_BOOLEAN, 8, NULL, 0x04, NULL, HFILL }},
{ &hf_lin_err_checksum,
{ "Checksum Error", "lin.errors.checksum_error",
FT_BOOLEAN, 8, NULL, 0x08, NULL, HFILL }},
{ &hf_lin_err_invalidid,
{ "Invalid ID Error", "lin.errors.invalid_id_error",
FT_BOOLEAN, 8, NULL, 0x10, NULL, HFILL }},
{ &hf_lin_err_overflow,
{ "Overflow Error", "lin.errors.overflow_error",
FT_BOOLEAN, 8, NULL, 0x20, NULL, HFILL }},
{ &hf_lin_event_id,
{ "Event ID", "lin.event_id",
FT_UINT32, BASE_HEX_DEC, VALS(lin_event_type_names), 0x00, NULL, HFILL }},
};
static gint *ett[] = {
&ett_lin,
&ett_lin_pid,
&ett_errors,
};
proto_lin = proto_register_protocol(LIN_NAME_LONG, LIN_NAME, LIN_NAME_FILTER);
lin_module = prefs_register_protocol(proto_lin, NULL);
proto_register_field_array(proto_lin, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
register_dissector(LIN_NAME_FILTER, dissect_lin, proto_lin);
/* the lin.frame_id subdissector table carries the bus id in the higher 16 bits */
subdissector_table = register_dissector_table("lin.frame_id", "LIN Frame ID", proto_lin, FT_UINT8, BASE_HEX);
heur_subdissector_list = register_heur_dissector_list(LIN_NAME_FILTER, proto_lin);
static uat_field_t lin_interface_mapping_uat_fields[] = {
UAT_FLD_HEX(interface_configs, interface_id, "Interface ID", "ID of the Interface with 0xffffffff = any (hex uint32 without leading 0x)"),
UAT_FLD_CSTRING(interface_configs, interface_name, "Interface Name", "Name of the Interface, empty = any (string)"),
UAT_FLD_HEX(interface_configs, bus_id, "Bus ID", "Bus ID of the Interface (hex uint16 without leading 0x)"),
UAT_END_FIELDS
};
lin_interface_uat = uat_new("LIN Interface Mapping",
sizeof(interface_config_t), /* record size */
DATAFILE_LIN_INTERFACE_MAPPING, /* filename */
TRUE, /* from profile */
(void**)&interface_configs, /* data_ptr */
&interface_config_num, /* numitems_ptr */
UAT_AFFECTS_DISSECTION, /* but not fields */
NULL, /* help */
copy_interface_config_cb, /* copy callback */
update_interface_config, /* update callback */
free_interface_config_cb, /* free callback */
post_update_lin_interfaces_cb, /* post update callback */
NULL, /* reset callback */
lin_interface_mapping_uat_fields /* UAT field definitions */
);
prefs_register_uat_preference(lin_module, "_lin_interface_mapping", "Interface Mapping",
"A table to define the mapping between interface and Bus ID.", lin_interface_uat);
}
void
proto_reg_handoff_lin(void) {
static dissector_handle_t lin_handle;
lin_handle = create_dissector_handle(dissect_lin, proto_lin);
dissector_add_uint("wtap_encap", WTAP_ENCAP_LIN, lin_handle);
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
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