mgcp_client_endpoint_fsm: on term, still let conns wait for DLCX OK

When the mgcp_client_endpoint_fsm terminates, do not directly pull each
conn FSM instance (mgcp_client_fsm) into oblivion as well. Those should
emit a DLCX and wait for the "OK" response before deallocating.

In programs using the mgcp client endpoint FSM (osmo-bsc, osmo-msc),
this gets rid of false LMGCP ERROR logging related to DLCX like this:

  Cannot find matching MGCP transaction for trans_id 71998

Related: SYS#5529
Change-Id: I8fbfec5533e9be9cc7ea550df1e6639a0a215973
This commit is contained in:
Neels Hofmeyr 2021-07-15 02:09:42 +02:00
parent 9de30e7cc4
commit 03fcc91aad
1 changed files with 29 additions and 1 deletions

View File

@ -990,6 +990,34 @@ static int osmo_mgcpc_ep_fsm_timer_cb(struct osmo_fsm_inst *fi)
return 0;
}
void osmo_mgcpc_ep_fsm_pre_term(struct osmo_fsm_inst *fi, enum osmo_fsm_term_cause cause)
{
int i;
struct osmo_mgcpc_ep *ep = osmo_mgcpc_ep_fi_mgwep(fi);
/* We want the mgcp_client_fsm to still stick around until it received the DLCX "OK" responses from the MGW. So
* it should not dealloc along with this ep_fsm instance. Instead, signal DLCX for each conn on the endpoint,
* and detach the mgcp_client_fsm from being a child-fsm.
*
* After mgcp_conn_delete(), an mgcp_client_fsm instance goes into ST_DLCX_RESP, which waits up to 4 seconds for
* a DLCX OK. If none is received in that time, the instance terminates. So cleanup of the instance is
* guaranteed. */
for (i = 0; i < ARRAY_SIZE(ep->ci); i++) {
struct osmo_mgcpc_ep_ci *ci = &ep->ci[i];
if (!ci->occupied || !ci->mgcp_client_fi)
continue;
/* mgcp_conn_delete() unlinks itself from this parent FSM implicitly and waits for the DLCX OK. */
mgcp_conn_delete(ci->mgcp_client_fi);
/* Forget all about this ci */
*ci = (struct osmo_mgcpc_ep_ci){
.ep = ep,
};
}
}
static struct osmo_fsm osmo_mgcpc_ep_fsm = {
.name = "mgw-endp",
.states = osmo_mgcpc_ep_fsm_states,
@ -997,5 +1025,5 @@ static struct osmo_fsm osmo_mgcpc_ep_fsm = {
.log_subsys = DLMGCP,
.event_names = osmo_mgcpc_ep_fsm_event_names,
.timer_cb = osmo_mgcpc_ep_fsm_timer_cb,
/* The FSM termination will automatically trigger any mgcp_client_fsm instances to DLCX. */
.pre_term = osmo_mgcpc_ep_fsm_pre_term,
};