sms charging: Implement Session Id to support charging sessions

Session Id:
- identify specific charging session
- must be globally and eternally unique
- h and l are decimal representations of the high and low 32 bits of a monotonically increasing 64-bit value

Change-Id: I986d62c34be849f3911cf2e4c83ead0ac8044571

5 files changed, 44 insertions, 0 deletions

diff --git a/openbsc/include/openbsc/gsm_data.h b/openbsc/include/openbsc/gsm_data.h
index d27757c68..18f097c06 100644
--- a/openbsc/include/openbsc/gsm_data.h
+++ b/openbsc/include/openbsc/gsm_data.h
@@ -286,6 +286,11 @@ struct gsm_tz {
 	int dst; /* daylight savings */
 };
 
+struct charging_session_id {
+	uint32_t h;	/* initialized to the current time */
+	uint32_t l;	/* incremented each time a session id is created */
+};
+
 struct gsm_network {
 	/* global parameters */
 	uint16_t country_code;
diff --git a/openbsc/include/openbsc/gsm_sup.h b/openbsc/include/openbsc/gsm_sup.h
index f74bb9846..26017365d 100644
--- a/openbsc/include/openbsc/gsm_sup.h
+++ b/openbsc/include/openbsc/gsm_sup.h
@@ -23,4 +23,7 @@ int subscr_purge_ms(struct gsm_subscriber *subscr);
 int subscr_tx_sms_message(struct gsm_subscriber *subscr,
                           struct gsm411_rp_hdr *rph);
 
+void init_charging_session_id(struct gsm_network *network);
+struct charging_session_id get_charging_session_id(struct gsm_network *network);
+
 #endif /* _GSM_SUP_H */
diff --git a/openbsc/include/openbsc/transaction.h b/openbsc/include/openbsc/transaction.h
index 234541caa..2a5a5af2a 100644
--- a/openbsc/include/openbsc/transaction.h
+++ b/openbsc/include/openbsc/transaction.h
@@ -34,6 +34,10 @@ struct gsm_trans {
 
 	/* SMS RP message reference */
 	uint8_t msg_ref;
+
+	/* Charging session id */
+	struct charging_session_id session_id;
+
 	/* handle SMS local */
 	uint8_t sms_local;
 
@@ -77,6 +81,8 @@ struct gsm_trans *trans_find_by_callref(struct gsm_network *net,
 					uint32_t callref);
 struct gsm_trans *trans_find_by_msgref(struct gsm_subscriber_connection *conn,
 					uint8_t msg_ref);
+struct gsm_trans *trans_find_by_session_id(struct gsm_network *net,
+				   uint8_t proto, struct charging_session_id session_id);
 struct gsm_trans *trans_find_by_lchan(struct gsm_lchan *lchan);
 
 struct gsm_trans *trans_alloc(struct gsm_network *net,
diff --git a/openbsc/src/libmsc/gsm_sup.c b/openbsc/src/libmsc/gsm_sup.c
index 1c33b447a..21e42adf1 100644
--- a/openbsc/src/libmsc/gsm_sup.c
+++ b/openbsc/src/libmsc/gsm_sup.c
@@ -247,6 +247,23 @@ static int rx_sms_message(struct gsup_client *sup_client,
 	return gsm411_send_rp_msg_subscr(subscr, msg);
 }
 
+void init_charging_session_id(struct gsm_network *network)
+{
+	network->session_id.h = (uint32_t)time(NULL);
+	network->session_id.l = 0;
+}
+struct charging_session_id get_charging_session_id(struct gsm_network *network)
+{
+	struct charging_session_id id;
+
+	if (++network->session_id.l == 0) /* overflow */
+		++network->session_id.h;
+	id.h = network->session_id.h;
+	id.l = network->session_id.l;
+
+	return id;
+}
+
 static int subscr_tx_sup_message(struct gsup_client *sup_client,
 								 struct gsm_subscriber *subscr,
 								 struct osmo_gsup_message *gsup_msg)
diff --git a/openbsc/src/libmsc/transaction.c b/openbsc/src/libmsc/transaction.c
index 0c1d08db1..077130868 100644
--- a/openbsc/src/libmsc/transaction.c
+++ b/openbsc/src/libmsc/transaction.c
@@ -77,6 +77,19 @@ struct gsm_trans *trans_find_by_msgref(struct gsm_subscriber_connection *conn,
 	return NULL;
 }
 
+struct gsm_trans *trans_find_by_session_id(struct gsm_network *net,
+			 uint8_t proto, struct charging_session_id session_id)
+{
+	struct gsm_trans *trans;
+	llist_for_each_entry(trans, &net->trans_list, entry) {
+		if (trans->protocol == proto &&
+		    trans->session_id.h == session_id.h &&
+		    trans->session_id.l == session_id.l)
+			return trans;
+	}
+	return NULL;
+}
+
 struct gsm_trans *trans_find_by_lchan(struct gsm_lchan *lchan)
 {
 	struct gsm_trans *temp;