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wireshark/epan/dissectors/packet-pdu-transport.c

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/* packet-pdu_transport.c
* PDU Transport dissector for FDN and others.
* By <lars.voelker@technica-engineering.de>
* Copyright 2020-2020 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
*/
/*
* This is a dissector for PDUs transported over UDP or TCP.
* The transported PDUs are typically CAN, FlexRay, LIN, or other protocols.
*
* The format is as follows:
* uint32 ID
* uint32 length
* uint8[length] data
* (restart with ID, if more data exists)
*
* One known implementation of this protocol is the AUTOSAR Socket Adaptor
* with Header Option turned on.
* See AUTOSAR "Specification of Socket Adaptor" (SWS), Section 7.3 PDU Header option:
* https://www.autosar.org/fileadmin/user_upload/standards/classic/20-11/AUTOSAR_SWS_SocketAdaptor.pdf
*/
#include <config.h>
#include <epan/packet.h>
#include <epan/prefs.h>
#include <epan/expert.h>
#include <epan/uat.h>
#include <epan/dissectors/packet-tcp.h>
#include <epan/reassemble.h>
#include <epan/dissectors/packet-udp.h>
#include <epan/dissectors/packet-pdu-transport.h>
#include <epan/decode_as.h>
#include <epan/proto_data.h>
void proto_register_pdu_transport(void);
void proto_reg_handoff_pdu_transport(void);
static int proto_pdu_transport = -1;
static dissector_handle_t pdu_transport_handle_udp = NULL;
static dissector_handle_t pdu_transport_handle_tcp = NULL;
static dissector_table_t subdissector_table = NULL;
#define PDU_TRANSPORT_NAME "PDU Transport"
#define PDU_TRANSPORT_HDR_LEN 8
/* header field */
static int hf_pdu_transport_id = -1;
static int hf_pdu_transport_length = -1;
static int hf_pdu_transport_payload = -1;
/* protocol tree items */
static gint ett_pdu_transport = -1;
/* expert info items */
static expert_field ef_pdu_transport_message_truncated = EI_INIT;
/********* UATs *********/
typedef struct _generic_one_id_string {
guint id;
gchar *name;
} generic_one_id_string_t;
static void
pdu_transport_free_key(gpointer key) {
wmem_free(wmem_epan_scope(), key);
}
static void
simple_free(gpointer data _U_) {
/* we need to free because of the g_strdup in post_update*/
g_free(data);
}
/* ID -> Name */
static void *
copy_generic_one_id_string_cb(void* n, const void* o, size_t size _U_) {
generic_one_id_string_t* new_rec = (generic_one_id_string_t*)n;
const generic_one_id_string_t* old_rec = (const generic_one_id_string_t*)o;
new_rec->name = g_strdup(old_rec->name);
new_rec->id = old_rec->id;
return new_rec;
}
static gboolean
update_generic_one_identifier_32bit(void *r, char **err) {
generic_one_id_string_t *rec = (generic_one_id_string_t *)r;
if (rec->name == NULL || rec->name[0] == 0) {
*err = g_strdup("Name cannot be empty");
return FALSE;
}
return TRUE;
}
static void
free_generic_one_id_string_cb(void*r) {
generic_one_id_string_t* rec = (generic_one_id_string_t*)r;
/* freeing result of g_strdup */
g_free(rec->name);
rec->name = NULL;
}
static void
post_update_one_id_string_template_cb(generic_one_id_string_t *data, guint data_num, GHashTable *ht) {
guint i;
int *key = NULL;
for (i = 0; i < data_num; i++) {
key = wmem_new(wmem_epan_scope(), int);
*key = data[i].id;
g_hash_table_insert(ht, key, g_strdup(data[i].name));
}
}
static char*
ht_lookup_name(GHashTable* ht, unsigned int identifier) {
char *tmp = NULL;
unsigned int *id = NULL;
if (ht == NULL) {
return NULL;
}
id = wmem_new(wmem_epan_scope(), unsigned int);
*id = (unsigned int)identifier;
tmp = (char *)g_hash_table_lookup(ht, id);
wmem_free(wmem_epan_scope(), id);
return tmp;
}
/*** UAT pdu_transport_CM_IDs ***/
#define DATAFILE_PDU_IDS "PDU_Transport_identifiers"
static GHashTable *data_pdu_transport_pdus = NULL;
static generic_one_id_string_t* pdu_transport_pdus = NULL;
static guint pdu_transport_pdus_num = 0;
UAT_HEX_CB_DEF(pdu_transport_pdus, id, generic_one_id_string_t)
UAT_CSTRING_CB_DEF(pdu_transport_pdus, name, generic_one_id_string_t)
static void
post_update_pdu_transport_pdus_cb(void) {
/* destroy old hash table, if it exists */
if (data_pdu_transport_pdus) {
g_hash_table_destroy(data_pdu_transport_pdus);
data_pdu_transport_pdus = NULL;
}
/* create new hash table */
data_pdu_transport_pdus = g_hash_table_new_full(g_int_hash, g_int_equal, &pdu_transport_free_key, &simple_free);
post_update_one_id_string_template_cb(pdu_transport_pdus, pdu_transport_pdus_num, data_pdu_transport_pdus);
}
static int
dissect_pdu_transport(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) {
proto_item *ti_top = NULL;
proto_item *ti = NULL;
proto_tree *pdu_transport_tree = NULL;
guint offset = 0;
tvbuff_t *subtvb = NULL;
gint tmp = 0;
guint32 length = 0;
guint32 pdu_id = 0;
const gchar *descr;
if (p_get_proto_data(pinfo->pool, pinfo, proto_pdu_transport, pinfo->curr_layer_num) != NULL) {
col_append_str(pinfo->cinfo, COL_INFO, ", ");
col_set_fence(pinfo->cinfo, COL_INFO);
}
col_set_str(pinfo->cinfo, COL_INFO, "PDU");
col_set_str(pinfo->cinfo, COL_PROTOCOL, PDU_TRANSPORT_NAME);
ti_top = proto_tree_add_item(tree, proto_pdu_transport, tvb, 0, -1, ENC_NA);
pdu_transport_tree = proto_item_add_subtree(ti_top, ett_pdu_transport);
if (tvb_captured_length_remaining(tvb, offset) < 8) {
expert_add_info(pinfo, ti_top, &ef_pdu_transport_message_truncated);
}
/* taken from packet-ip.c
* if pdu_transport is not referenced from any filters we don't need to worry about
* generating any tree items. We must do this after we created the actual
* protocol above so that proto hier stat still works though.
* XXX: Note that because of the following optimization expert items must
* not be generated inside of an 'if (tree) ...'
* so that Analyze ! Expert ... will work.
*/
if (!proto_field_is_referenced(tree, proto_pdu_transport)) {
pdu_transport_tree = NULL;
}
ti = proto_tree_add_item_ret_uint(pdu_transport_tree, hf_pdu_transport_id, tvb, offset, 4, ENC_BIG_ENDIAN, &pdu_id);
offset += 4;
proto_tree_add_item_ret_uint(pdu_transport_tree, hf_pdu_transport_length, tvb, offset, 4, ENC_BIG_ENDIAN, &length);
offset += 4;
descr = ht_lookup_name(data_pdu_transport_pdus, pdu_id);
if (descr != NULL) {
proto_item_append_text(ti_top, ", ID 0x%x (%s), Length: %d", pdu_id, descr, length);
proto_item_append_text(ti, " (%s)", descr);
col_append_fstr(pinfo->cinfo, COL_INFO, " (ID: 0x%x, %s)", pdu_id, descr);
} else {
proto_item_append_text(ti_top, ", ID 0x%x, Length: %d", pdu_id, length);
col_append_fstr(pinfo->cinfo, COL_INFO, " (ID: 0x%x)", pdu_id);
}
p_add_proto_data(pinfo->pool, pinfo, proto_pdu_transport, pinfo->curr_layer_num, GUINT_TO_POINTER(pdu_id));
tmp = tvb_captured_length_remaining(tvb, offset);
if ((gint)length <= tmp) {
proto_tree_add_item(pdu_transport_tree, hf_pdu_transport_payload, tvb, offset, length, ENC_NA);
subtvb = tvb_new_subset_length_caplen(tvb, offset, length, length);
} else {
proto_tree_add_item(pdu_transport_tree, hf_pdu_transport_payload, tvb, offset, tmp, ENC_NA);
subtvb = tvb_new_subset_length_caplen(tvb, offset, tmp, length);
expert_add_info(pinfo, ti_top, &ef_pdu_transport_message_truncated);
}
if (subtvb != NULL) {
pdu_transport_info_t pdu_t_info;
pdu_t_info.id = pdu_id;
dissector_try_uint_new(subdissector_table, pdu_id, subtvb, pinfo, tree, FALSE, (void *)(&pdu_t_info));
}
offset += (gint)length;
col_set_fence(pinfo->cinfo, COL_INFO);
return offset;
}
static guint
get_pdu_transport_message_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset, void* data _U_) {
return PDU_TRANSPORT_HDR_LEN + (guint)tvb_get_ntohl(tvb, offset + 4);
}
static int
dissect_pdu_transport_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data) {
tcp_dissect_pdus(tvb, pinfo, tree, TRUE, PDU_TRANSPORT_HDR_LEN, get_pdu_transport_message_len, dissect_pdu_transport, data);
return tvb_reported_length(tvb);
}
static int
dissect_pdu_transport_udp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data) {
return udp_dissect_pdus(tvb, pinfo, tree, PDU_TRANSPORT_HDR_LEN, NULL, get_pdu_transport_message_len, dissect_pdu_transport, data);
}
static void pdu_transport_id_prompt(packet_info *pinfo, gchar* result)
{
snprintf(result, MAX_DECODE_AS_PROMPT_LEN, "PDU Transport ID 0x%08x as",
GPOINTER_TO_UINT(p_get_proto_data(pinfo->pool, pinfo, proto_pdu_transport, pinfo->curr_layer_num)));
}
static gpointer pdu_transport_id_value(packet_info *pinfo)
{
/* Limitation: This only returns the last proto_data, since udp_dissect_pdus gives us the same layer for all. */
return p_get_proto_data(pinfo->pool, pinfo, proto_pdu_transport, pinfo->curr_layer_num);
}
void
proto_register_pdu_transport(void) {
module_t *pdu_transport_module = NULL;
expert_module_t *expert_module_pdu_transport = NULL;
uat_t *pdu_transport_pduid_uat = NULL;
static hf_register_info hf[] = {
{ &hf_pdu_transport_id,
{ "ID", "pdu_transport.id", FT_UINT32, BASE_HEX, NULL, 0x0, NULL, HFILL }},
{ &hf_pdu_transport_length,
{ "Length", "pdu_transport.length", FT_UINT32, BASE_DEC, NULL, 0x0, NULL, HFILL }},
{ &hf_pdu_transport_payload,
{ "Payload", "pdu_transport.payload", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }},
};
static gint *ett[] = {
&ett_pdu_transport,
};
static ei_register_info ei[] = {
{ &ef_pdu_transport_message_truncated,{ "pdu_transport.message_truncated",
PI_MALFORMED, PI_ERROR, "PDU Transport Truncated message!", EXPFILL } },
};
/* Decode As handling */
static build_valid_func pdu_transport_da_build_value[1] = {pdu_transport_id_value};
static decode_as_value_t pdu_transport_da_values = {pdu_transport_id_prompt, 1, pdu_transport_da_build_value};
static decode_as_t pdu_transport_da = { "pdu_transport", "pdu_transport.id", 1, 0, &pdu_transport_da_values,
NULL, NULL, decode_as_default_populate_list,
decode_as_default_reset, decode_as_default_change, NULL };
proto_pdu_transport = proto_register_protocol("PDU Transport Protocol", PDU_TRANSPORT_NAME, "pdu_transport");
proto_register_field_array(proto_pdu_transport, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
pdu_transport_module = prefs_register_protocol(proto_pdu_transport, NULL);
expert_module_pdu_transport = expert_register_protocol(proto_pdu_transport);
expert_register_field_array(expert_module_pdu_transport, ei, array_length(ei));
static uat_field_t pdu_transport_cm_id_uat_fields[] = {
UAT_FLD_HEX(pdu_transport_pdus, id, "ID", "ID (hex uint32)"),
UAT_FLD_CSTRING(pdu_transport_pdus, name, "Name", "Name of the PDU (string)"),
UAT_END_FIELDS
};
pdu_transport_pduid_uat = uat_new("pdu_transport Capture Modules",
sizeof(generic_one_id_string_t), /* record size */
DATAFILE_PDU_IDS, /* filename */
TRUE, /* from profile */
(void**)&pdu_transport_pdus, /* data_ptr */
&pdu_transport_pdus_num, /* numitems_ptr */
UAT_AFFECTS_DISSECTION, /* but not fields */
NULL, /* help */
copy_generic_one_id_string_cb, /* copy callback */
update_generic_one_identifier_32bit, /* update callback */
free_generic_one_id_string_cb, /* free callback */
post_update_pdu_transport_pdus_cb, /* post update callback */
NULL, /* reset callback */
pdu_transport_cm_id_uat_fields /* UAT field definitions */
);
prefs_register_uat_preference(pdu_transport_module, "_udf_pdu_transport_pdus", "PDUs",
"A table to define names and IDs of PDUs", pdu_transport_pduid_uat);
subdissector_table = register_dissector_table("pdu_transport.id", "PDU Transport ID", proto_pdu_transport, FT_UINT32, BASE_HEX);
register_decode_as(&pdu_transport_da);
}
void
proto_reg_handoff_pdu_transport(void) {
pdu_transport_handle_udp = register_dissector("pdu_transport_over_udp", dissect_pdu_transport_udp, proto_pdu_transport);
pdu_transport_handle_tcp = register_dissector("pdu_transport_over_tcp", dissect_pdu_transport_tcp, proto_pdu_transport);
dissector_add_uint_range_with_preference("udp.port", "", pdu_transport_handle_udp);
dissector_add_uint_range_with_preference("tcp.port", "", pdu_transport_handle_tcp);
}
/*
* 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:
*/
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