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Remove magic numbers; adjust dissection for new payload offsets

This commit is contained in:
foreverska 2020-11-23 20:22:07 -06:00 committed by AndersBroman
parent 1c3186ef2b
commit 569cf94c28
1 changed files with 21 additions and 25 deletions
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46
epan/dissectors/packet-obd-ii.c
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@ -26,7 +26,6 @@ static int proto_obdii = -1;
static int ett_obdii = -1;
static int hf_obdii_data_bytes = -1;
static int hf_obdii_mode = -1;
static int hf_obdii_raw_value = -1;
@ -121,8 +120,10 @@ static int hf_obdii_mode01_torque_reference_engine = -1;
#define ODBII_CAN_RESPONSE_ID_LOWER_MASK_EFF 0xFF00
#define ODBII_CAN_RESPONSE_ID_UPPER_MASK_EFF 0x00FF
#define ODBII_MODE_POS 0x00
#define ODBII_PID_POS 0x01
#define OBDII_MODE_POS 0x00
#define OBDII_PID_POS 0x01
#define OBDII_VAL_OFF 0x02
#define OBDII_MODE07_DATA_OFF 0x01
#define OBDII_MODE01_PIDS_SUPPORT00 0x00
#define OBDII_MODE01_MONITOR_STATUS 0x01
@ -625,16 +626,16 @@ dissect_obdii_common_torque(tvbuff_t *tvb, struct obdii_packet_info *oinfo, prot
static void
dissect_obdii_mode_01(tvbuff_t *tvb, struct obdii_packet_info *oinfo, proto_tree *tree)
{
guint8 pid = tvb_get_guint8(tvb, ODBII_PID_POS);
guint8 pid = tvb_get_guint8(tvb, OBDII_PID_POS);
int value_offset;
gboolean handled = FALSE;
col_append_fstr(oinfo->pinfo->cinfo, COL_INFO, "- %s", val_to_str_ext(pid, &obdii_mode01_pid_vals_ext, "Unknown (%.2x)"));
proto_tree_add_uint(tree, hf_obdii_mode01_pid, tvb, 2, 1, pid);
proto_tree_add_uint(tree, hf_obdii_mode01_pid, tvb, OBDII_PID_POS, 1, pid);
proto_tree_add_item(tree, hf_obdii_raw_value, tvb, 3, MIN(oinfo->value_bytes, 4), ENC_NA);
proto_tree_add_item(tree, hf_obdii_raw_value, tvb, OBDII_VAL_OFF, MIN(oinfo->value_bytes, 4), ENC_NA);
value_offset = 3;
value_offset = OBDII_VAL_OFF;
oinfo->value_offset = value_offset;
/* https://en.wikipedia.org/wiki/OBD-II_PIDs#Mode_01 */
@ -1195,7 +1196,7 @@ dissect_obdii_mode_01(tvbuff_t *tvb, struct obdii_packet_info *oinfo, proto_tree
static void
dissect_obdii_mode_07(tvbuff_t *tvb, struct obdii_packet_info *oinfo, proto_tree *tree)
{
proto_tree_add_item(tree, hf_obdii_raw_value, tvb, 3, MIN(oinfo->value_bytes, 5), ENC_NA);
proto_tree_add_item(tree, hf_obdii_raw_value, tvb, OBDII_MODE07_DATA_OFF, MIN(oinfo->value_bytes, 5), ENC_NA);
/* display raw */
col_append_fstr(oinfo->pinfo->cinfo, COL_INFO, ": <");
@ -1224,9 +1225,9 @@ dissect_obdii_query(tvbuff_t *tvb, struct obdii_packet_info *oinfo, proto_tree *
pid = 0; /* Should never be required but set to satisfy petri-dish */
}
else if (pid_len == 1)
pid = tvb_get_guint8(tvb, ODBII_PID_POS);
pid = tvb_get_guint8(tvb, OBDII_PID_POS);
else if (pid_len == 2)
pid = tvb_get_ntohs(tvb, ODBII_PID_POS);
pid = tvb_get_ntohs(tvb, OBDII_PID_POS);
else
return 0;
@ -1236,7 +1237,7 @@ dissect_obdii_query(tvbuff_t *tvb, struct obdii_packet_info *oinfo, proto_tree *
{
case 0x01:
pid_str = val_to_str_ext(pid, &obdii_mode01_pid_vals_ext, "Unknown (%.2x)");
proto_tree_add_uint(tree, hf_obdii_mode01_pid, tvb, 2, pid_len, pid);
proto_tree_add_uint(tree, hf_obdii_mode01_pid, tvb, OBDII_PID_POS, pid_len, pid);
col_append_fstr(oinfo->pinfo->cinfo, COL_INFO, " Request[%.3x] %s - %s", oinfo->can_id, mode_str, pid_str);
break;
@ -1257,13 +1258,13 @@ dissect_obdii_response(tvbuff_t *tvb, struct obdii_packet_info *oinfo, proto_tre
{
col_append_fstr(oinfo->pinfo->cinfo, COL_INFO, "Response[%.3x] %s ", oinfo->can_id, val_to_str(oinfo->mode, obdii_mode_vals, "Unknown (%.2x)"));
oinfo->value_bytes = 1 + (oinfo->data_bytes - 3);
oinfo->value_bytes = oinfo->data_bytes - OBDII_VAL_OFF;
if (oinfo->value_bytes >= 1) oinfo->valueA = tvb_get_guint8(tvb, 2);
if (oinfo->value_bytes >= 2) oinfo->valueB = tvb_get_guint8(tvb, 3);
if (oinfo->value_bytes >= 3) oinfo->valueC = tvb_get_guint8(tvb, 4);
if (oinfo->value_bytes >= 4) oinfo->valueD = tvb_get_guint8(tvb, 5);
if (oinfo->value_bytes >= 5) oinfo->valueE = tvb_get_guint8(tvb, 6);
if (oinfo->value_bytes >= 1) oinfo->valueA = tvb_get_guint8(tvb, OBDII_VAL_OFF);
if (oinfo->value_bytes >= 2) oinfo->valueB = tvb_get_guint8(tvb, OBDII_VAL_OFF + 1);
if (oinfo->value_bytes >= 3) oinfo->valueC = tvb_get_guint8(tvb, OBDII_VAL_OFF + 2);
if (oinfo->value_bytes >= 4) oinfo->valueD = tvb_get_guint8(tvb, OBDII_VAL_OFF + 3);
if (oinfo->value_bytes >= 5) oinfo->valueE = tvb_get_guint8(tvb, OBDII_VAL_OFF + 4);
switch (oinfo->mode)
{
@ -1319,7 +1320,7 @@ dissect_obdii(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
return 0;
data_bytes = tvb_reported_length(tvb);
mode = tvb_get_guint8(tvb, ODBII_MODE_POS);
mode = tvb_get_guint8(tvb, OBDII_MODE_POS);
/* Mode 7 is a datalength of 1, all other queries either 2 or 3 bytes */
if (id_is_query)
@ -1332,7 +1333,7 @@ dissect_obdii(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
if (id_is_response)
{
if (!(data_bytes >= 3 && data_bytes <= 7))
if (data_bytes < 2)
return 0;
if (mode < 0x40)
return 0;
@ -1346,8 +1347,7 @@ dissect_obdii(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
ti = proto_tree_add_item(tree, proto_obdii, tvb, 0, -1, ENC_NA);
obdii_tree = proto_item_add_subtree(ti, ett_obdii);
proto_tree_add_item(obdii_tree, hf_obdii_data_bytes, tvb, 0, 1, ENC_NA);
proto_tree_add_uint(obdii_tree, hf_obdii_mode, tvb, 1, 1, mode);
proto_tree_add_uint(obdii_tree, hf_obdii_mode, tvb, OBDII_MODE_POS, 1, mode);
memset(&oinfo, 0, sizeof(oinfo));
oinfo.pinfo = pinfo;
@ -1377,16 +1377,12 @@ void
proto_register_obdii(void)
{
static hf_register_info hf[] = {
{ &hf_obdii_data_bytes,
{ "Number of data bytes", "obd-ii.data_bytes", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL },
},
{ &hf_obdii_mode,
{ "Mode", "obd-ii.mode", FT_UINT8, BASE_HEX, VALS(obdii_mode_vals), 0x0, NULL, HFILL },
},
{ &hf_obdii_raw_value,
{ "Raw value", "obd-ii.raw_value", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL },
},
{ &hf_obdii_mode01_pid,
{ "PID", "obd-ii.mode01_pid", FT_UINT16, BASE_HEX | BASE_EXT_STRING, VALS_EXT_PTR(&obdii_mode01_pid_vals_ext), 0x0, NULL, HFILL },
},