fix gscon clear 2/n: proper state transition to ST_CLEARING

The way the ST_CLEARING is entered before this patch has various
symptoms of how I / we used osmo_fsm when we were still FSM amateurs in
Osmocom. Patch that up:

- In gscon_bssmap_clear(), ask for a state transition to ST_CLEARING
  first. Go ahead only if it is allowed.

- move the Clear Request messaging to ST_CLEARING's onenter function.

- Fix the timeout behavior: by using conn_fsm_state_chg(), use the
  actual proper X4 timer value for ST_CLEARING from VTY configuration
  instead of hardcoded magic numbers.

Related: OS#5337
Change-Id: I234b2a754d0c98031056981823cdbc187e977741
changes/13/26613/3
Neels Hofmeyr 1 year ago committed by laforge
parent c984dc1a86
commit c2dba7c5b9
  1. 35
      src/osmo-bsc/bsc_subscr_conn_fsm.c

@ -141,10 +141,24 @@ int gscon_sigtran_send(struct gsm_subscriber_connection *conn, struct msgb *msg)
static void gscon_bssmap_clear(struct gsm_subscriber_connection *conn,
enum gsm0808_cause cause)
{
/* already clearing? */
switch (conn->fi->state) {
case ST_CLEARING:
return;
default:
break;
}
conn->clear_cause = cause;
conn_fsm_state_chg(ST_CLEARING);
}
static void gscon_fsm_clearing_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
{
struct msgb *resp;
int rc;
conn->clear_cause = cause;
struct gsm_subscriber_connection *conn = fi->priv;
enum gsm0808_cause cause = conn->clear_cause;
if (conn->rx_clear_command) {
LOGPFSML(conn->fi, LOGL_DEBUG, "Not sending BSSMAP CLEAR REQUEST, already got CLEAR COMMAND from MSC\n");
@ -152,14 +166,14 @@ static void gscon_bssmap_clear(struct gsm_subscriber_connection *conn,
}
if (!conn->sccp.msc) {
LOGPFSML(conn->fi, LOGL_ERROR, "Unable to deliver BSSMAP Clear Request message, no MSC for this conn\n");
LOGPFSML(fi, LOGL_ERROR, "Unable to deliver BSSMAP Clear Request message, no MSC for this conn\n");
return;
}
LOGPFSML(conn->fi, LOGL_DEBUG, "Tx BSSMAP CLEAR REQUEST(%s) to MSC\n", gsm0808_cause_name(cause));
LOGPFSML(fi, LOGL_DEBUG, "Tx BSSMAP CLEAR REQUEST(%s) to MSC\n", gsm0808_cause_name(cause));
resp = gsm0808_create_clear_rqst(cause);
if (!resp) {
LOGPFSML(conn->fi, LOGL_ERROR, "Unable to compose BSSMAP Clear Request message\n");
LOGPFSML(fi, LOGL_ERROR, "Unable to compose BSSMAP Clear Request message\n");
return;
}
@ -355,8 +369,6 @@ static void gscon_fsm_init(struct osmo_fsm_inst *fi, uint32_t event, void *data)
osmo_fsm_inst_state_name(conn->fi));
}
gscon_bssmap_clear(conn, GSM0808_CAUSE_EQUIPMENT_FAILURE);
if (conn->fi->state != ST_CLEARING)
osmo_fsm_inst_state_chg(fi, ST_CLEARING, 60, -4);
return;
default:
OSMO_ASSERT(false);
@ -376,7 +388,6 @@ static void gscon_fsm_wait_cc(struct osmo_fsm_inst *fi, uint32_t event, void *da
confirmed connection, then instead simply drop the connection */
LOGPFSML(fi, LOGL_INFO,
"Connection confirmed but lchan was dropped previously, clearing conn\n");
osmo_fsm_inst_state_chg(conn->fi, ST_CLEARING, 60, -4);
gscon_bssmap_clear(conn, GSM0808_CAUSE_EQUIPMENT_FAILURE);
break;
}
@ -705,6 +716,7 @@ static const struct osmo_fsm_state gscon_fsm_states[] = {
},
[ST_CLEARING] = {
.name = "CLEARING",
.onenter = gscon_fsm_clearing_onenter,
/* dead end state */
},
};
@ -763,11 +775,6 @@ void gscon_lchan_releasing(struct gsm_subscriber_connection *conn, struct gsm_lc
yet so we cannot release it. First wait for the CC, and release in gscon_fsm_wait_cc(). */
break;
default:
/* Ensure that the FSM is in ST_CLEARING. */
osmo_fsm_inst_state_chg(conn->fi, ST_CLEARING, 60, -4);
/* fall thru, omit an error log if already in ST_CLEARING */
case ST_CLEARING:
/* Request a Clear Command from the MSC. */
gscon_bssmap_clear(conn, GSM0808_CAUSE_EQUIPMENT_FAILURE);
break;
}
@ -806,8 +813,7 @@ void gscon_forget_lchan(struct gsm_subscriber_connection *conn, struct gsm_lchan
osmo_fsm_inst_name(conn->fi), detach_label);
}
if ((conn->fi && conn->fi->state != ST_CLEARING)
&& !conn->lchan
if (!conn->lchan
&& !conn->ho.new_lchan
&& !conn->assignment.new_lchan
&& !conn->lcs.loc_req)
@ -1205,7 +1211,6 @@ static void gsm0808_send_rsl_dtap(struct gsm_subscriber_connection *conn,
failed_to_send:
LOGPFSML(conn->fi, LOGL_ERROR, "Tx BSSMAP CLEAR REQUEST to MSC\n");
gscon_bssmap_clear(conn, GSM0808_CAUSE_EQUIPMENT_FAILURE);
osmo_fsm_inst_state_chg(conn->fi, ST_ACTIVE, 0, 0);
}
void gscon_submit_rsl_dtap(struct gsm_subscriber_connection *conn,

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