libmsc/gsm_09_11.c: implement guard timer for NCSS sessions
It may happen that either the MS or an EUSE would become
unresponsive during a call independent SS session, e.g.
due to a bug, or a dropped message. In such cases, the
corresponding transaction would remain unfreed forever.
This change introduces a guard timer, that prevents keeping
'stalled' NCSS sessions forever. As soon as it expires, both
sides (i.e. MS and EUSE) are getting notified, and the
transaction is being released.
By default, the timer expires after 30 seconds. As soon as
either the MS, or an EUSE initiates any activity,
the watchdog timer is rescheduled.
The timeout value can be configured from the VTY:
msc
...
! Use 0 to disable this timer
ncss guard-timeout 30
Please note that changing the timeout value at run-time
doesn't affect the existing NCSS sessions, excepting the
case when the timer is disabled at run-time.
This change makes TC_lu_and_ss_session_timeout pass.
Change-Id: Icf4d87c45e90324764073e8230e0fb9cb96dd9cb
Related Change-Id: (TTCN) I3e1791773d56617172ae27a46889a1ae4d400e2f
Related: OS#3655
diff --git a/src/libmsc/gsm_09_11.c b/src/libmsc/gsm_09_11.c
index d2ad0b7..c133656 100644
--- a/src/libmsc/gsm_09_11.c
+++ b/src/libmsc/gsm_09_11.c
@@ -51,6 +51,39 @@
/* FIXME: choose a proper range */
static uint32_t new_callref = 0x20000001;
+static void ncss_session_timeout_handler(void *_trans)
+{
+ struct gsm_trans *trans = (struct gsm_trans *) _trans;
+ struct osmo_gsup_message gsup_msg = { 0 };
+
+ /* The timeout might be disabled from the VTY */
+ if (trans->net->ncss_guard_timeout == 0)
+ return;
+
+ LOGP(DMM, LOGL_NOTICE, "SS/USSD session timeout, releasing "
+ "transaction (trans=%p, callref=%x)\n", trans, trans->callref);
+
+ /* Indicate connection release to subscriber (if active) */
+ if (trans->conn != NULL) {
+ /* This pair of cause location and value is used by commercial networks */
+ msc_send_ussd_release_complete_cause(trans->conn, trans->transaction_id,
+ GSM48_CAUSE_LOC_PUN_S_LU, GSM48_CC_CAUSE_NORMAL_UNSPEC);
+ }
+
+ /* Terminate GSUP session with EUSE */
+ gsup_msg.message_type = OSMO_GSUP_MSGT_PROC_SS_ERROR;
+ OSMO_STRLCPY_ARRAY(gsup_msg.imsi, trans->vsub->imsi);
+
+ gsup_msg.session_state = OSMO_GSUP_SESSION_STATE_END;
+ gsup_msg.session_id = trans->callref;
+ gsup_msg.cause = GMM_CAUSE_NET_FAIL;
+
+ osmo_gsup_client_enc_send(trans->net->vlr->gsup_client, &gsup_msg);
+
+ /* Finally, release this transaction */
+ trans_free(trans);
+}
+
/* Entry point for call independent MO SS messages */
int gsm0911_rcv_nc_ss(struct ran_conn *conn, struct msgb *msg)
{
@@ -108,6 +141,10 @@
return -ENOMEM;
}
+ /* Init inactivity timer */
+ osmo_timer_setup(&trans->ss.timer_guard,
+ ncss_session_timeout_handler, trans);
+
/* Count active NC SS/USSD sessions */
osmo_counter_inc(conn->network->active_nc_ss);
@@ -116,6 +153,12 @@
cm_service_request_concludes(conn, msg);
}
+ /* (Re)schedule the inactivity timer */
+ if (conn->network->ncss_guard_timeout > 0) {
+ osmo_timer_schedule(&trans->ss.timer_guard,
+ conn->network->ncss_guard_timeout, 0);
+ }
+
/* Attempt to extract Facility IE */
rc = gsm0480_extract_ie_by_tag(gh, msgb_l3len(msg),
&facility_ie, &facility_ie_len, GSM0480_IE_FACILITY);
@@ -233,6 +276,12 @@
transt->conn = ran_conn_get(conn, RAN_CONN_USE_TRANS_NC_SS);
transt->paging_request = NULL;
+ /* (Re)schedule the inactivity timer */
+ if (conn->network->ncss_guard_timeout > 0) {
+ osmo_timer_schedule(&transt->ss.timer_guard,
+ conn->network->ncss_guard_timeout, 0);
+ }
+
/* Send stored message */
ss_msg = transt->ss.msg;
gh = (struct gsm48_hdr *) msgb_push(ss_msg, sizeof(*gh));
@@ -317,6 +366,10 @@
}
trans->transaction_id = tid;
+ /* Init inactivity timer */
+ osmo_timer_setup(&trans->ss.timer_guard,
+ ncss_session_timeout_handler, trans);
+
/* Attempt to find connection */
conn = connection_for_subscr(vsub);
if (conn) {
@@ -371,6 +424,9 @@
if (trans->ss.msg != NULL)
msgb_free(trans->ss.msg);
+ /* Stop inactivity timer */
+ osmo_timer_del(&trans->ss.timer_guard);
+
/* One session less */
osmo_counter_dec(trans->net->active_nc_ss);
}
@@ -420,6 +476,12 @@
return 0;
}
+ /* (Re)schedule the inactivity timer */
+ if (net->ncss_guard_timeout > 0) {
+ osmo_timer_schedule(&trans->ss.timer_guard,
+ net->ncss_guard_timeout, 0);
+ }
+
/* Allocate and prepare a new MT message */
ss_msg = gsm48_msgb_alloc_name("GSM 04.08 SS/USSD");
gh = (struct gsm48_hdr *) msgb_push(ss_msg, sizeof(*gh));
diff --git a/src/libmsc/msc_vty.c b/src/libmsc/msc_vty.c
index 078b83a..5aa533b 100644
--- a/src/libmsc/msc_vty.c
+++ b/src/libmsc/msc_vty.c
@@ -375,6 +375,18 @@
"mncc-guard-timeout <0-255>",
MNCC_GUARD_TIMEOUT_STR MNCC_GUARD_TIMEOUT_VALUE_STR);
+#define NCSS_STR "Configure call independent Supplementary Services\n"
+
+DEFUN(cfg_msc_ncss_guard_timeout,
+ cfg_msc_ncss_guard_timeout_cmd,
+ "ncss guard-timeout <0-255>",
+ NCSS_STR "Set guard timer for session activity\n"
+ "guard timer value (sec.), or 0 to disable\n")
+{
+ gsmnet->ncss_guard_timeout = atoi(argv[0]);
+ return CMD_SUCCESS;
+}
+
DEFUN(cfg_msc_assign_tmsi, cfg_msc_assign_tmsi_cmd,
"assign-tmsi",
"Assign TMSI during Location Updating.\n")
@@ -496,6 +508,8 @@
vty_out(vty, " mncc external %s%s", gsmnet->mncc_sock_path, VTY_NEWLINE);
vty_out(vty, " mncc guard-timeout %i%s",
gsmnet->mncc_guard_timeout, VTY_NEWLINE);
+ vty_out(vty, " ncss guard-timeout %i%s",
+ gsmnet->ncss_guard_timeout, VTY_NEWLINE);
vty_out(vty, " %sassign-tmsi%s",
gsmnet->vlr->cfg.assign_tmsi? "" : "no ", VTY_NEWLINE);
@@ -1588,6 +1602,7 @@
install_element(MSC_NODE, &cfg_msc_mncc_external_cmd);
install_element(MSC_NODE, &cfg_msc_mncc_guard_timeout_cmd);
install_element(MSC_NODE, &cfg_msc_deprecated_mncc_guard_timeout_cmd);
+ install_element(MSC_NODE, &cfg_msc_ncss_guard_timeout_cmd);
install_element(MSC_NODE, &cfg_msc_no_assign_tmsi_cmd);
install_element(MSC_NODE, &cfg_msc_auth_tuple_max_reuse_count_cmd);
install_element(MSC_NODE, &cfg_msc_auth_tuple_reuse_on_error_cmd);
diff --git a/src/libmsc/osmo_msc.c b/src/libmsc/osmo_msc.c
index 9828da1..5c6f0aa 100644
--- a/src/libmsc/osmo_msc.c
+++ b/src/libmsc/osmo_msc.c
@@ -54,6 +54,7 @@
net->t3212 = 5;
net->mncc_guard_timeout = 180;
+ net->ncss_guard_timeout = 30;
net->paging_response_timer = MSC_PAGING_RESPONSE_TIMER_DEFAULT;