sms: Address the TODO and schedule the next SMS for an active subscriber

When one SMS has been delivered check if a second SMS can be scheduled
to that subscriber. If nothing can be scheduled kick the normal SMS queue
as one slot has become free now. Otherwise send the SMS and create a
pending entry.

1 files changed, 45 insertions, 6 deletions

diff --git a/openbsc/src/libmsc/sms_queue.c b/openbsc/src/libmsc/sms_queue.c
index b7753270a..536bfdd14 100644
--- a/openbsc/src/libmsc/sms_queue.c
+++ b/openbsc/src/libmsc/sms_queue.c
@@ -280,6 +280,45 @@ static void sms_submit_pending(void *_data)
 	LOGP(DLSMS, LOGL_DEBUG, "SMSqueue added %d messages in %d rounds\n", attempted, rounds);
 }
 
+/**
+ * Send the next SMS or trigger the queue
+ */
+static void sms_send_next(struct gsm_subscriber *subscr)
+{
+	struct gsm_sms_queue *smsq = subscr->net->sms_queue;
+	struct gsm_sms_pending *pending;
+	struct gsm_sms *sms;
+
+	/* the subscriber should not be in the queue */
+	OSMO_ASSERT(!sms_subscriber_is_pending(smsq, subscr));
+
+	/* check for more messages for this subscriber */
+	sms = db_sms_get_unsent_for_subscr(subscr);
+	if (!sms)
+		goto no_pending_sms;
+
+	/* No sms should be scheduled right now */
+	OSMO_ASSERT(!sms_is_in_pending(smsq, sms));
+
+	/* Remember that we deliver this SMS and send it */
+	pending = sms_pending_from(smsq, sms);
+	if (!pending) {
+		LOGP(DLSMS, LOGL_ERROR,
+			"Failed to create pending SMS entry.\n");
+		sms_free(sms);
+		goto no_pending_sms;
+	}
+
+	smsq->pending += 1;
+	llist_add_tail(&pending->entry, &smsq->pending_sms);
+	gsm411_send_sms_subscr(sms->receiver, sms);
+	return;
+
+no_pending_sms:
+	/* Try to send the SMS to avoid the queue being stuck */
+	sms_submit_pending(subscr->net->sms_queue);
+}
+
 /*
  * Kick off the queue again.
  */
@@ -377,6 +416,7 @@ static int sms_sms_cb(unsigned int subsys, unsigned int signal,
 	struct gsm_network *network = handler_data;
 	struct sms_signal_data *sig_sms = signal_data;
 	struct gsm_sms_pending *pending;
+	struct gsm_subscriber *subscr;
 
 	/* We got a new SMS and maybe should launch the queue again. */
 	if (signal == S_SMS_SUBMITTED || signal == S_SMS_SMMA) {
@@ -400,14 +440,13 @@ static int sms_sms_cb(unsigned int subsys, unsigned int signal,
 
 	switch (signal) {
 	case S_SMS_DELIVERED:
+		/* Remember the subscriber and clear the pending entry */
 		network->sms_queue->pending -= 1;
+		subscr = subscr_get(pending->subscr);
 		sms_pending_free(pending);
-		/*
-		 * TODO: we could specially make sure to re-use the existing
-		 * radio connection here. Maybe something like the readyForSM
-		 * code.
-		 */
-		sms_submit_pending(network->sms_queue);
+		/* Attempt to send another SMS to this subscriber */
+		sms_send_next(subscr);
+		subscr_put(subscr);
 		break;
 	case S_SMS_MEM_EXCEEDED:
 		network->sms_queue->pending -= 1;