net: gptp: stepsRemoved is wrongly assigned #93180
Description
Describe the bug
According to IEEE 802.1AS, when RM is better than the S (local clock), the stepsRemoved in masterPriority should be set to SRM + 1 .
However, in the current implementation, it appears that this value is not updated accordingly and instead retains the previous value.
static void update_bmca(int port,
int best_port,
struct gptp_global_ds *global_ds,
struct gptp_default_ds *default_ds,
struct gptp_priority_vector *gm_prio)
{
struct gptp_port_bmca_data *bmca_data = GPTP_PORT_BMCA_DATA(port);
/* Update masterPriorityVector for the port. */
/* best_port == 0 means S is better than any RM */
if (best_port == 0) {
memcpy(&bmca_data->master_priority, gm_prio,
sizeof(struct gptp_priority_vector));
bmca_data->master_priority.port_number = htons(port);
bmca_data->master_priority.src_port_id.port_number =
htons(port);
} else {
/* this block does not update bmca_data->master_priority.steps_removed */
memcpy(&bmca_data->master_priority.root_system_id,
&gm_prio->root_system_id,
sizeof(struct gptp_root_system_identity));
memcpy(bmca_data->master_priority.src_port_id.clk_id,
default_ds->clk_id, GPTP_CLOCK_ID_LEN);
bmca_data->master_priority.port_number = htons(port);
bmca_data->master_priority.src_port_id.port_number =
htons(port);
}The suggested fix would be like this.
diff --git a/subsys/net/l2/ethernet/gptp/gptp_mi.c b/subsys/net/l2/ethernet/gptp/gptp_mi.c
index 997d2f7b9c5..d2100405183 100644
--- a/subsys/net/l2/ethernet/gptp/gptp_mi.c
+++ b/subsys/net/l2/ethernet/gptp/gptp_mi.c
@@ -1758,6 +1758,8 @@ static void update_bmca(int port,
bmca_data->master_priority.port_number = htons(port);
bmca_data->master_priority.src_port_id.port_number =
htons(port);
+ /* gm_prio->steps_removed is assigned as SRM+1 in compute_best_vector */
+ bmca_data->master_priority.steps_removed = gm_prio->steps_removed;
}
switch (bmca_data->info_is) {Since my understanding of the specification might not be perfect, I would appreciate it if someone could confirm whether this interpretation is correct or not.
Regression
- This is a regression.
Steps to reproduce
No response
Relevant log output
Impact
Intermittent – Occurs occasionally; hard to reproduce.
Environment
Additional Context
No response