Structural reform: Get rid of osmo_bsc_sccp_con

There was always a 1:1 correspondence between gsm_subscriber_connection
and osmo_bsc_sccp_con, so there's really no point in having two separate
dynamically allocated data structures with pointers back and forth and
another linked list around.

Let's merge osmo_bsc_sccp_con into gsm_subscriber_connection for
simplicity.

The resulting code might not be elegant in places, but I've tried to
do only the most simple changes in this patch, while further
simplifications can be done in later subsequent patches.

As a side-effect, this patch also fixes lchan clearing if the MSC
(or the local SCCP provider) hard-disconnects the SCCP connection.

Change-Id: Idd2b733477ee90d24dec369755a00f1c39c93f39

1 files changed, 19 insertions, 32 deletions

diff --git a/src/osmo-bsc/osmo_bsc_api.c b/src/osmo-bsc/osmo_bsc_api.c
index 1caaeee7c..465832c82 100644
--- a/src/osmo-bsc/osmo_bsc_api.c
+++ b/src/osmo-bsc/osmo_bsc_api.c
@@ -32,13 +32,13 @@
 #include <osmocom/bsc/osmo_bsc_sigtran.h>
 
 #define return_when_not_connected(conn) \
-	if (!conn->sccp_con) {\
+	if (conn->sccp.state != SUBSCR_SCCP_ST_CONNECTED) {\
 		LOGP(DMSC, LOGL_ERROR, "MSC Connection not present.\n"); \
 		return; \
 	}
 
 #define return_when_not_connected_val(conn, ret) \
-	if (!conn->sccp_con) {\
+	if (conn->sccp.state != SUBSCR_SCCP_ST_CONNECTED) {\
 		LOGP(DMSC, LOGL_ERROR, "MSC Connection not present.\n"); \
 		return ret; \
 	}
@@ -48,7 +48,7 @@
 		LOGP(DMSC, LOGL_ERROR, "Failed to allocate response.\n"); \
 		return; \
 	} \
-	osmo_bsc_sigtran_send(conn->sccp_con, resp);
+	osmo_bsc_sigtran_send(conn, resp);
 
 static int bsc_clear_request(struct gsm_subscriber_connection *conn, uint32_t cause);
 static int complete_layer3(struct gsm_subscriber_connection *conn,
@@ -135,12 +135,12 @@ static int bsc_filter_data(struct gsm_subscriber_connection *conn,
 	req.ctx = conn;
 	req.black_list = NULL;
 	req.access_lists = bsc_access_lists();
-	req.local_lst_name = conn->sccp_con->msc->acc_lst_name;
+	req.local_lst_name = conn->sccp.msc->acc_lst_name;
 	req.global_lst_name = conn_get_bts(conn)->network->bsc_data->acc_lst_name;
 	req.bsc_nr = 0;
 
 	rc = bsc_msg_filter_data(gh, msgb_l3len(msg), &req,
-				&conn->sccp_con->filter_state,
+				&conn->filter_state,
 				&cause);
 	*lu_cause = cause.lu_reject_cause;
 	return rc;
@@ -280,27 +280,27 @@ static int complete_layer3(struct gsm_subscriber_connection *conn,
 	}
 
 	if (imsi)
-		conn->sccp_con->filter_state.imsi = talloc_steal(conn, imsi);
-	conn->sccp_con->filter_state.con_type = con_type;
+		conn->filter_state.imsi = talloc_steal(conn, imsi);
+	conn->filter_state.con_type = con_type;
 
 	/* check return value, if failed check msg for and send USSD */
 
-	network_code = get_network_code_for_msc(conn->sccp_con->msc);
-	country_code = get_country_code_for_msc(conn->sccp_con->msc);
-	lac = get_lac_for_msc(conn->sccp_con->msc, conn_get_bts(conn));
-	ci = get_ci_for_msc(conn->sccp_con->msc, conn_get_bts(conn));
+	network_code = get_network_code_for_msc(conn->sccp.msc);
+	country_code = get_country_code_for_msc(conn->sccp.msc);
+	lac = get_lac_for_msc(conn->sccp.msc, conn_get_bts(conn));
+	ci = get_ci_for_msc(conn->sccp.msc, conn_get_bts(conn));
 
 	bsc_scan_bts_msg(conn, msg);
 
 	resp = gsm0808_create_layer3(msg, network_code, country_code, lac, ci);
 	if (!resp) {
 		LOGP(DMSC, LOGL_DEBUG, "Failed to create layer3 message.\n");
-		osmo_bsc_sigtran_del_conn(conn->sccp_con);
+		osmo_bsc_sigtran_del_conn(conn);
 		return BSC_API_CONN_POL_REJECT;
 	}
 
-	if (osmo_bsc_sigtran_open_conn(conn->sccp_con, resp) != 0) {
-		osmo_bsc_sigtran_del_conn(conn->sccp_con);
+	if (osmo_bsc_sigtran_open_conn(conn, resp) != 0) {
+		osmo_bsc_sigtran_del_conn(conn);
 		msgb_free(resp);
 		return BSC_API_CONN_POL_REJECT;
 	}
@@ -314,14 +314,11 @@ static int complete_layer3(struct gsm_subscriber_connection *conn,
 static int move_to_msc(struct gsm_subscriber_connection *_conn,
 		       struct msgb *msg, struct bsc_msc_data *msc)
 {
-	struct osmo_bsc_sccp_con *old_con = _conn->sccp_con;
-
 	/*
 	 * 1. Give up the old connection.
 	 * This happens by sending a clear request to the MSC,
 	 * it should end with the MSC releasing the connection.
 	 */
-	old_con->conn = NULL;
 	bsc_clear_request(_conn, 0);
 
 	/*
@@ -329,7 +326,6 @@ static int move_to_msc(struct gsm_subscriber_connection *_conn,
 	 * MSC. If it fails the caller will need to handle this
 	 * properly.
 	 */
-	_conn->sccp_con = NULL;
 	if (complete_layer3(_conn, msg, msc) != BSC_API_CONN_POL_ACCEPT) {
 		gsm0808_clear(_conn);
 		bsc_subscr_con_free(_conn);
@@ -416,7 +412,7 @@ static void bsc_dtap(struct gsm_subscriber_connection *conn, uint8_t link_id, st
 	/* Check the filter */
 	if (bsc_filter_data(conn, msg, &lu_cause) < 0) {
 		bsc_maybe_lu_reject(conn,
-					conn->sccp_con->filter_state.con_type,
+					conn->filter_state.con_type,
 					lu_cause);
 		bsc_clear_request(conn, 0);
 		return;
@@ -435,7 +431,7 @@ static void bsc_assign_compl(struct gsm_subscriber_connection *conn, uint8_t rr_
 	struct msgb *resp;
 	return_when_not_connected(conn);
 
-	if (is_ipaccess_bts(conn_get_bts(conn)) && conn->sccp_con->user_plane.rtp_ip) {
+	if (is_ipaccess_bts(conn_get_bts(conn)) && conn->user_plane.rtp_ip) {
 		/* NOTE: In a network that makes use of an IPA base station
 		 * and AoIP, we have to wait until the BTS reports its RTP
 		 * IP/Port combination back to BSC via RSL. Unfortunately, the
@@ -473,27 +469,18 @@ static void bsc_assign_fail(struct gsm_subscriber_connection *conn,
 
 static int bsc_clear_request(struct gsm_subscriber_connection *conn, uint32_t cause)
 {
-	struct osmo_bsc_sccp_con *sccp;
 	struct msgb *resp;
 	return_when_not_connected_val(conn, 1);
 
 	LOGP(DMSC, LOGL_INFO, "Tx MSC CLEAR REQUEST\n");
 
-	/*
-	 * Remove the connection from BSC<->SCCP part, the SCCP part
-	 * will either be cleared by channel release or MSC disconnect
-	 */
-	sccp = conn->sccp_con;
-	sccp->conn = NULL;
-	conn->sccp_con = NULL;
-
 	resp = gsm0808_create_clear_rqst(GSM0808_CAUSE_RADIO_INTERFACE_FAILURE);
 	if (!resp) {
 		LOGP(DMSC, LOGL_ERROR, "Failed to allocate response.\n");
 		return 1;
 	}
 
-	osmo_bsc_sigtran_send(sccp, resp);
+	osmo_bsc_sigtran_send(conn, resp);
 	return 1;
 }
 
@@ -515,14 +502,14 @@ static void bsc_mr_config(struct gsm_subscriber_connection *conn,
 	struct bsc_msc_data *msc;
 	struct gsm48_multi_rate_conf *ms_conf, *bts_conf;
 
-	if (!conn->sccp_con) {
+	if (!conn) {
 		LOGP(DMSC, LOGL_ERROR,
 		     "No msc data available on conn %p. Audio will be broken.\n",
 		     conn);
 		return;
 	}
 
-	msc = conn->sccp_con->msc;
+	msc = conn->sccp.msc;
 
 	/* initialize the data structure */
 	lchan->mr_ms_lv[0] = sizeof(*ms_conf);