expiration: Allow to disable the periodic location updating procedure

Disable the periodic LU using "no periodic location update" VTY
command. In that case set the expire_lu to 0 which will then be
translated to a NULL in the database layer. This leads to a bit of
copy and paste in the db_sync_subscriber method but I don't see
how we could easily use 'datetime(%i, 'unixepoch')' and 'NULL'
at the same time.

Change the query to find expired queries to check for NOT NULL
and the time being in the past. This means if there are still
old subscribers in the database they might not be expired. One
would need to execute a query like "UPATE Subscriber SET expire_lu
= 0 WHERE expire_lu is null". The same applies when disabling the
periodic LU. One would need to update the database by hand.

Manual tests executed/passed:

1.) periodic LU enabled:

  * use gst LUTest.st to do a LU
  * UPDATE Subscriber SET expire_lu=datetime('now');
  * observe the subscriber being expired (it was)

2.) periodic LU disabled:

  * use gst LUTest.st to do a LU
  * verify that the expire_lu is NULL in the database

3 files changed, 67 insertions, 28 deletions

diff --git a/openbsc/src/libbsc/bsc_vty.c b/openbsc/src/libbsc/bsc_vty.c
index b2b7977c7..45df90f5f 100644
--- a/openbsc/src/libbsc/bsc_vty.c
+++ b/openbsc/src/libbsc/bsc_vty.c
@@ -506,8 +506,13 @@ static void config_write_bts_single(struct vty *vty, struct gsm_bts *bts)
 				(sp->penalty_time*20)+20, VTY_NEWLINE);
 	}
 
-	vty_out(vty, "  periodic location update %u%s",
-		bts->si_common.chan_desc.t3212 * 6, VTY_NEWLINE);
+	/* Is periodic LU enabled or disabled? */
+	if (bts->si_common.chan_desc.t3212 == 0)
+		vty_out(vty, "  no periodic location update%s", VTY_NEWLINE);
+	else
+		vty_out(vty, "  periodic location update %u%s",
+			bts->si_common.chan_desc.t3212 * 6, VTY_NEWLINE);
+
 	vty_out(vty, "  channel allocator %s%s",
 		bts->chan_alloc_reverse ? "descending" : "ascending",
 		VTY_NEWLINE);
@@ -2036,6 +2041,19 @@ DEFUN(cfg_bts_per_loc_upd, cfg_bts_per_loc_upd_cmd,
 	return CMD_SUCCESS;
 }
 
+DEFUN(cfg_bts_no_per_loc_upd, cfg_bts_no_per_loc_upd_cmd,
+      "no periodic location update",
+      NO_STR
+      "Periodic Location Updating Interval\n"
+      "Periodic Location Updating Interval\n"
+      "Periodic Location Updating Interval\n")
+{
+	struct gsm_bts *bts = vty->index;
+
+	bts->si_common.chan_desc.t3212 = 0;
+	return CMD_SUCCESS;
+}
+
 #define GPRS_TEXT	"GPRS Packet Network\n"
 
 DEFUN(cfg_bts_prs_bvci, cfg_bts_gprs_bvci_cmd,
@@ -3053,6 +3071,7 @@ int bsc_vty_init(const struct log_info *cat)
 	install_element(BTS_NODE, &cfg_bts_rach_ec_allowed_cmd);
 	install_element(BTS_NODE, &cfg_bts_ms_max_power_cmd);
 	install_element(BTS_NODE, &cfg_bts_per_loc_upd_cmd);
+	install_element(BTS_NODE, &cfg_bts_no_per_loc_upd_cmd);
 	install_element(BTS_NODE, &cfg_bts_cell_resel_hyst_cmd);
 	install_element(BTS_NODE, &cfg_bts_rxlev_acc_min_cmd);
 	install_element(BTS_NODE, &cfg_bts_cell_bar_qualify_cmd);
diff --git a/openbsc/src/libmsc/db.c b/openbsc/src/libmsc/db.c
index 8a7ff90ca..21abce9de 100644
--- a/openbsc/src/libmsc/db.c
+++ b/openbsc/src/libmsc/db.c
@@ -639,7 +639,7 @@ static void db_set_from_query(struct gsm_subscriber *subscr, dbi_conn result)
 	if (!dbi_result_field_is_null(result, "expire_lu"))
 		subscr->expire_lu = dbi_result_get_datetime(result, "expire_lu");
 	else
-		subscr->expire_lu = 0;
+		subscr->expire_lu = GSM_SUBSCRIBER_NO_EXPIRATION;
 
 	subscr->authorized = dbi_result_get_uint(result, "authorized");
 }
@@ -766,23 +766,42 @@ int db_sync_subscriber(struct gsm_subscriber *subscriber)
 	} else
 		q_tmsi = strdup("NULL");
 
-	result = dbi_conn_queryf(conn,
-		"UPDATE Subscriber "
-		"SET updated = datetime('now'), "
-		"name = %s, "
-		"extension = %s, "
-		"authorized = %i, "
-		"tmsi = %s, "
-		"lac = %i, "
-		"expire_lu = datetime(%i, 'unixepoch') "
-		"WHERE imsi = %s ",
-		q_name,
-		q_extension,
-		subscriber->authorized,
-		q_tmsi,
-		subscriber->lac,
-		(int) subscriber->expire_lu,
-		subscriber->imsi);
+	if (subscriber->expire_lu == GSM_SUBSCRIBER_NO_EXPIRATION) {
+		result = dbi_conn_queryf(conn,
+			"UPDATE Subscriber "
+			"SET updated = datetime('now'), "
+			"name = %s, "
+			"extension = %s, "
+			"authorized = %i, "
+			"tmsi = %s, "
+			"lac = %i, "
+			"expire_lu = NULL "
+			"WHERE imsi = %s ",
+			q_name,
+			q_extension,
+			subscriber->authorized,
+			q_tmsi,
+			subscriber->lac,
+			subscriber->imsi);
+	} else {
+		result = dbi_conn_queryf(conn,
+			"UPDATE Subscriber "
+			"SET updated = datetime('now'), "
+			"name = %s, "
+			"extension = %s, "
+			"authorized = %i, "
+			"tmsi = %s, "
+			"lac = %i, "
+			"expire_lu = datetime(%i, 'unixepoch') "
+			"WHERE imsi = %s ",
+			q_name,
+			q_extension,
+			subscriber->authorized,
+			q_tmsi,
+			subscriber->lac,
+			(int) subscriber->expire_lu,
+			subscriber->imsi);
+	}
 
 	free(q_tmsi);
 	free(q_name);
@@ -852,8 +871,8 @@ int db_subscriber_expire(void *priv, void (*callback)(void *priv, long long unsi
 			"SELECT id "
 			"FROM Subscriber "
 			"WHERE lac != 0 AND "
-				"( expire_lu is NULL "
-				"OR expire_lu < datetime('now') ) "
+				"( expire_lu is NOT NULL "
+				"AND expire_lu < datetime('now') ) "
 			"LIMIT 1");
 	if (!result) {
 		LOGP(DDB, LOGL_ERROR, "Failed to get expired subscribers\n");
diff --git a/openbsc/src/libmsc/gsm_subscriber.c b/openbsc/src/libmsc/gsm_subscriber.c
index 6abb0d832..5ace8f666 100644
--- a/openbsc/src/libmsc/gsm_subscriber.c
+++ b/openbsc/src/libmsc/gsm_subscriber.c
@@ -333,8 +333,14 @@ int subscr_update_expire_lu(struct gsm_subscriber *s, struct gsm_bts *bts)
 	 * periodic updating in decihours. Mark the subscriber as
 	 * inactive if it missed two consecutive location updates.
 	 * Timeout is twice the t3212 value plus one minute */
-	s->expire_lu = time(NULL) +
+
+	/* Is expiration handling enabled? */
+	if (bts->si_common.chan_desc.t3212 == 0)
+		s->expire_lu = GSM_SUBSCRIBER_NO_EXPIRATION;
+	else
+		s->expire_lu = time(NULL) +
 			(bts->si_common.chan_desc.t3212 * 60 * 6 * 2) + 60;
+
 	rc = db_sync_subscriber(s);
 	db_subscriber_update(s);
 	return rc;
@@ -354,11 +360,6 @@ int subscr_update(struct gsm_subscriber *s, struct gsm_bts *bts, int reason)
 		LOGP(DMM, LOGL_INFO, "Subscriber %s ATTACHED LAC=%u\n",
 			subscr_name(s), s->lac);
 
-		/* FIXME: We should allow 0 for T3212 as well to disable the
-		 * location update period. In that case we will need a way to
-		 * indicate that in the database and then reenable that value in
-		 * VTY.
-		 */
 		/*
 		 * The below will set a new expire_lu but as a side-effect
 		 * the new lac will be saved in the database.