1 files changed, 271 insertions, 115 deletions

diff --git a/src/osmo-bsc/lb.c b/src/osmo-bsc/lb.c
index 77fa1165b..6f3cfac7c 100644
--- a/src/osmo-bsc/lb.c
+++ b/src/osmo-bsc/lb.c
@@ -30,6 +30,7 @@
 #include <osmocom/bsc/debug.h>
 #include <osmocom/bsc/osmo_bsc_sigtran.h>
 #include <osmocom/bsc/lcs_loc_req.h>
+#include <osmocom/bsc/bssmap_reset.h>
 
 static struct gsm_subscriber_connection *get_bsc_conn_by_lb_conn_id(int conn_id)
 {
@@ -45,8 +46,7 @@ static struct gsm_subscriber_connection *get_bsc_conn_by_lb_conn_id(int conn_id)
 }
 
 /* Send reset to SMLC */
-int bssmap_le_tx_reset()
-	// TODO use this -- patch coming up
+int bssmap_le_tx_reset(void)
 {
 	struct osmo_ss7_instance *ss7;
 	struct msgb *msg;
@@ -58,18 +58,23 @@ int bssmap_le_tx_reset()
 		},
 	};
 
-	ss7 = osmo_ss7_instance_find(bsc_gsmnet->smlc.cs7_instance);
+	if (!bsc_gsmnet->smlc->sccp_user) {
+		LOGP(DRESET, LOGL_DEBUG, "Not sending RESET to SMLC, Lb link down\n");
+		return -1;
+	}
+
+	ss7 = osmo_ss7_instance_find(bsc_gsmnet->smlc->cs7_instance);
 	OSMO_ASSERT(ss7);
-	LOGP(DLCS, LOGL_NOTICE, "Sending RESET to SMLC: %s\n", osmo_sccp_addr_name(ss7, &bsc_gsmnet->smlc.smlc_addr));
+	LOGP(DRESET, LOGL_INFO, "Sending RESET to SMLC: %s\n", osmo_sccp_addr_name(ss7, &bsc_gsmnet->smlc->smlc_addr));
 	msg = osmo_bssap_le_enc(&reset);
 
-	rate_ctr_inc(&bsc_gsmnet->smlc.ctrs->ctr[SMLC_CTR_BSSMAP_LE_TX_UDT_RESET]);
-	return osmo_sccp_tx_unitdata_msg(bsc_gsmnet->smlc.sccp_user, &bsc_gsmnet->smlc.bsc_addr,
-					 &bsc_gsmnet->smlc.smlc_addr, msg);
+	rate_ctr_inc(rate_ctr_group_get_ctr(bsc_gsmnet->smlc->ctrs, SMLC_CTR_BSSMAP_LE_TX_UDT_RESET));
+	return osmo_sccp_tx_unitdata_msg(bsc_gsmnet->smlc->sccp_user, &bsc_gsmnet->smlc->bsc_addr,
+					 &bsc_gsmnet->smlc->smlc_addr, msg);
 }
 
 /* Send reset-ack to SMLC */
-int bssmap_le_tx_reset_ack()
+int bssmap_le_tx_reset_ack(void)
 {
 	struct osmo_ss7_instance *ss7;
 	struct msgb *msg;
@@ -80,35 +85,14 @@ int bssmap_le_tx_reset_ack()
 		},
 	};
 
-	ss7 = osmo_ss7_instance_find(bsc_gsmnet->smlc.cs7_instance);
+	ss7 = osmo_ss7_instance_find(bsc_gsmnet->smlc->cs7_instance);
 	OSMO_ASSERT(ss7);
-	LOGP(DLCS, LOGL_NOTICE, "Tx RESET ACK to SMLC: %s\n", osmo_sccp_addr_name(ss7, &bsc_gsmnet->smlc.smlc_addr));
+	LOGP(DRESET, LOGL_NOTICE, "Sending RESET ACK to SMLC: %s\n", osmo_sccp_addr_name(ss7, &bsc_gsmnet->smlc->smlc_addr));
 	msg = osmo_bssap_le_enc(&reset_ack);
 
-	rate_ctr_inc(&bsc_gsmnet->smlc.ctrs->ctr[SMLC_CTR_BSSMAP_LE_TX_UDT_RESET_ACK]);
-	return osmo_sccp_tx_unitdata_msg(bsc_gsmnet->smlc.sccp_user, &bsc_gsmnet->smlc.bsc_addr,
-					 &bsc_gsmnet->smlc.smlc_addr, msg);
-}
-
-static int bssmap_le_handle_reset(const struct bssmap_le_pdu *pdu)
-{
-	struct gsm_subscriber_connection *conn;
-	int rc;
-
-	/* Abort all ongoing Location Requests */
-	llist_for_each_entry(conn, &bsc_gsmnet->subscr_conns, entry)
-		lcs_loc_req_reset(conn);
-
-	rc = bssmap_le_tx_reset_ack();
-	if (!rc)
-		bsc_gsmnet->smlc.ready = true;
-	return rc;
-}
-
-static int bssmap_le_handle_reset_ack()
-{
-	bsc_gsmnet->smlc.ready = true;
-	return 0;
+	rate_ctr_inc(rate_ctr_group_get_ctr(bsc_gsmnet->smlc->ctrs, SMLC_CTR_BSSMAP_LE_TX_UDT_RESET_ACK));
+	return osmo_sccp_tx_unitdata_msg(bsc_gsmnet->smlc->sccp_user, &bsc_gsmnet->smlc->bsc_addr,
+					 &bsc_gsmnet->smlc->smlc_addr, msg);
 }
 
 static int handle_unitdata_from_smlc(const struct osmo_sccp_addr *smlc_addr, struct msgb *msg,
@@ -116,22 +100,22 @@ static int handle_unitdata_from_smlc(const struct osmo_sccp_addr *smlc_addr, str
 {
 	struct osmo_ss7_instance *ss7;
 	struct bssap_le_pdu bssap_le;
-	struct osmo_bssap_le_err *err;
-	struct rate_ctr *ctr = bsc_gsmnet->smlc.ctrs->ctr;
+	struct osmo_bssap_le_err *err = NULL;
+	struct rate_ctr_group *ctrg = bsc_gsmnet->smlc->ctrs;
 
 	ss7 = osmo_sccp_get_ss7(osmo_sccp_get_sccp(scu));
 	OSMO_ASSERT(ss7);
 
-	if (osmo_sccp_addr_cmp(smlc_addr, &bsc_gsmnet->smlc.smlc_addr, OSMO_SCCP_ADDR_T_MASK)) {
+	if (osmo_sccp_addr_cmp(smlc_addr, &bsc_gsmnet->smlc->smlc_addr, OSMO_SCCP_ADDR_T_MASK)) {
 		LOGP(DLCS, LOGL_ERROR, "Rx BSSMAP-LE UnitData from unknown remote address: %s\n",
 		     osmo_sccp_addr_name(ss7, smlc_addr));
-		rate_ctr_inc(&ctr[SMLC_CTR_BSSMAP_LE_RX_UNKNOWN_PEER]);
+		rate_ctr_inc(rate_ctr_group_get_ctr(ctrg, SMLC_CTR_BSSMAP_LE_RX_UNKNOWN_PEER));
 		return -EINVAL;
 	}
 
 	if (osmo_bssap_le_dec(&bssap_le, &err, msg, msg)) {
 		LOGP(DLCS, LOGL_ERROR, "Rx BSSAP-LE UnitData with error: %s\n", err->logmsg);
-		rate_ctr_inc(&ctr[SMLC_CTR_BSSMAP_LE_RX_UDT_ERR_INVALID_MSG]);
+		rate_ctr_inc(rate_ctr_group_get_ctr(ctrg, SMLC_CTR_BSSMAP_LE_RX_UDT_ERR_INVALID_MSG));
 		return -EINVAL;
 	}
 
@@ -142,15 +126,17 @@ static int handle_unitdata_from_smlc(const struct osmo_sccp_addr *smlc_addr, str
 
 	switch (bssap_le.bssmap_le.msg_type) {
 	case BSSMAP_LE_MSGT_RESET:
-		rate_ctr_inc(&ctr[SMLC_CTR_BSSMAP_LE_RX_UDT_RESET]);
+		rate_ctr_inc(rate_ctr_group_get_ctr(ctrg, SMLC_CTR_BSSMAP_LE_RX_UDT_RESET));
 		LOGP(DLCS, LOGL_NOTICE, "RESET from SMLC: %s\n", osmo_sccp_addr_name(ss7, smlc_addr));
-		return bssmap_le_handle_reset(&bssap_le.bssmap_le);
+		return osmo_fsm_inst_dispatch(bsc_gsmnet->smlc->bssmap_reset->fi, BSSMAP_RESET_EV_RX_RESET, NULL);
+
 	case BSSMAP_LE_MSGT_RESET_ACK:
-		rate_ctr_inc(&ctr[SMLC_CTR_BSSMAP_LE_RX_UDT_RESET_ACK]);
+		rate_ctr_inc(rate_ctr_group_get_ctr(ctrg, SMLC_CTR_BSSMAP_LE_RX_UDT_RESET_ACK));
 		LOGP(DLCS, LOGL_NOTICE, "RESET-ACK from SMLC: %s\n", osmo_sccp_addr_name(ss7, smlc_addr));
-		return bssmap_le_handle_reset_ack();
+		return osmo_fsm_inst_dispatch(bsc_gsmnet->smlc->bssmap_reset->fi, BSSMAP_RESET_EV_RX_RESET_ACK, NULL);
+
 	default:
-		rate_ctr_inc(&ctr[SMLC_CTR_BSSMAP_LE_RX_UDT_ERR_INVALID_MSG]);
+		rate_ctr_inc(rate_ctr_group_get_ctr(ctrg, SMLC_CTR_BSSMAP_LE_RX_UDT_ERR_INVALID_MSG));
 		LOGP(DLCS, LOGL_ERROR, "Rx unimplemented UDT message type %s\n",
 		     osmo_bssap_le_pdu_to_str_c(OTC_SELECT, &bssap_le));
 		return -EINVAL;
@@ -255,23 +241,23 @@ static int lb_open_conn(struct gsm_subscriber_connection *conn, struct msgb *msg
 		return -EINVAL;
 	}
 
-	conn_id = bsc_sccp_inst_next_conn_id(bsc_gsmnet->smlc.sccp);
+	conn_id = bsc_sccp_inst_next_conn_id(bsc_gsmnet->smlc->sccp);
 	if (conn_id < 0) {
 		LOGPFSMSL(conn->fi, DLCS, LOGL_ERROR, "Unable to allocate SCCP Connection ID for BSSMAP-LE to SMLC\n");
 		return -ENOSPC;
 	}
 	conn->lcs.lb.conn_id = conn_id;
-	ss7 = osmo_ss7_instance_find(bsc_gsmnet->smlc.cs7_instance);
+	ss7 = osmo_ss7_instance_find(bsc_gsmnet->smlc->cs7_instance);
 	OSMO_ASSERT(ss7);
 	LOGPFSMSL(conn->fi, DLCS, LOGL_INFO, "Opening new SCCP connection (id=%i) to SMLC: %s\n", conn_id,
-		  osmo_sccp_addr_name(ss7, &bsc_gsmnet->smlc.smlc_addr));
+		  osmo_sccp_addr_name(ss7, &bsc_gsmnet->smlc->smlc_addr));
 
-	rc = osmo_sccp_tx_conn_req_msg(bsc_gsmnet->smlc.sccp_user, conn_id, &bsc_gsmnet->smlc.bsc_addr,
-				       &bsc_gsmnet->smlc.smlc_addr, msg);
+	rc = osmo_sccp_tx_conn_req_msg(bsc_gsmnet->smlc->sccp_user, conn_id, &bsc_gsmnet->smlc->bsc_addr,
+				       &bsc_gsmnet->smlc->smlc_addr, msg);
 	if (rc >= 0)
-		rate_ctr_inc(&bsc_gsmnet->smlc.ctrs->ctr[SMLC_CTR_BSSMAP_LE_TX_SUCCESS]);
+		rate_ctr_inc(rate_ctr_group_get_ctr(bsc_gsmnet->smlc->ctrs, SMLC_CTR_BSSMAP_LE_TX_SUCCESS));
 	else
-		rate_ctr_inc(&bsc_gsmnet->smlc.ctrs->ctr[SMLC_CTR_BSSMAP_LE_TX_ERR_SEND]);
+		rate_ctr_inc(rate_ctr_group_get_ctr(bsc_gsmnet->smlc->ctrs, SMLC_CTR_BSSMAP_LE_TX_ERR_SEND));
 	if (rc >= 0)
 		conn->lcs.lb.state = SUBSCR_SCCP_ST_WAIT_CONN_CONF;
 
@@ -282,7 +268,7 @@ void lb_close_conn(struct gsm_subscriber_connection *conn)
 {
 	if (conn->lcs.lb.state == SUBSCR_SCCP_ST_NONE)
 		return;
-	osmo_sccp_tx_disconn(bsc_gsmnet->smlc.sccp_user, conn->lcs.lb.conn_id, &bsc_gsmnet->smlc.bsc_addr, 0);
+	osmo_sccp_tx_disconn(bsc_gsmnet->smlc->sccp_user, conn->lcs.lb.conn_id, &bsc_gsmnet->smlc->bsc_addr, 0);
 	conn->lcs.lb.state = SUBSCR_SCCP_ST_NONE;
 }
 
@@ -294,6 +280,15 @@ int lb_send(struct gsm_subscriber_connection *conn, const struct bssap_le_pdu *b
 
 	OSMO_ASSERT(conn);
 
+	if (!bssmap_reset_is_conn_ready(bsc_gsmnet->smlc->bssmap_reset)) {
+		LOGPFSMSL(conn->fi, DLCS, LOGL_ERROR, "Lb link to SMLC is not ready (no RESET-ACK), cannot send %s\n",
+			  osmo_bssap_le_pdu_to_str_c(OTC_SELECT, bssap_le));
+		/* If the remote side was lost, make sure that the SCCP conn is discarded in the local state and towards
+		 * the STP. */
+		lb_close_conn(conn);
+		return -EINVAL;
+	}
+
 	msg = osmo_bssap_le_enc(bssap_le);
 	if (!msg) {
 		LOGPFSMSL(conn->fi, DLCS, LOGL_ERROR, "Failed to encode %s\n",
@@ -307,11 +302,11 @@ int lb_send(struct gsm_subscriber_connection *conn, const struct bssap_le_pdu *b
 	}
 
 	LOGPFSMSL(conn->fi, DLCS, LOGL_DEBUG, "Tx %s\n", osmo_bssap_le_pdu_to_str_c(OTC_SELECT, bssap_le));
-	rc = osmo_sccp_tx_data_msg(bsc_gsmnet->smlc.sccp_user, conn->lcs.lb.conn_id, msg);
+	rc = osmo_sccp_tx_data_msg(bsc_gsmnet->smlc->sccp_user, conn->lcs.lb.conn_id, msg);
 	if (rc >= 0)
-		rate_ctr_inc(&bsc_gsmnet->smlc.ctrs->ctr[SMLC_CTR_BSSMAP_LE_TX_SUCCESS]);
+		rate_ctr_inc(rate_ctr_group_get_ctr(bsc_gsmnet->smlc->ctrs, SMLC_CTR_BSSMAP_LE_TX_SUCCESS));
 	else
-		rate_ctr_inc(&bsc_gsmnet->smlc.ctrs->ctr[SMLC_CTR_BSSMAP_LE_TX_ERR_SEND]);
+		rate_ctr_inc(rate_ctr_group_get_ctr(bsc_gsmnet->smlc->ctrs, SMLC_CTR_BSSMAP_LE_TX_ERR_SEND));
 
 count_tx:
 	if (rc < 0)
@@ -319,24 +314,24 @@ count_tx:
 
 	switch (bssap_le->bssmap_le.msg_type) {
 	case BSSMAP_LE_MSGT_PERFORM_LOC_REQ:
-		rate_ctr_inc(&bsc_gsmnet->smlc.ctrs->ctr[SMLC_CTR_BSSMAP_LE_TX_DT1_PERFORM_LOCATION_REQUEST]);
+		rate_ctr_inc(rate_ctr_group_get_ctr(bsc_gsmnet->smlc->ctrs, SMLC_CTR_BSSMAP_LE_TX_DT1_PERFORM_LOCATION_REQUEST));
 		break;
 	case BSSMAP_LE_MSGT_PERFORM_LOC_ABORT:
-		rate_ctr_inc(&bsc_gsmnet->smlc.ctrs->ctr[SMLC_CTR_BSSMAP_LE_TX_DT1_PERFORM_LOCATION_ABORT]);
+		rate_ctr_inc(rate_ctr_group_get_ctr(bsc_gsmnet->smlc->ctrs, SMLC_CTR_BSSMAP_LE_TX_DT1_PERFORM_LOCATION_ABORT));
 		break;
 	case BSSMAP_LE_MSGT_CONN_ORIENTED_INFO:
 		switch (bssap_le->bssmap_le.conn_oriented_info.apdu.msg_type) {
 		case BSSLAP_MSGT_TA_RESPONSE:
-			rate_ctr_inc(&bsc_gsmnet->smlc.ctrs->ctr[SMLC_CTR_BSSMAP_LE_TX_DT1_BSSLAP_TA_RESPONSE]);
+			rate_ctr_inc(rate_ctr_group_get_ctr(bsc_gsmnet->smlc->ctrs, SMLC_CTR_BSSMAP_LE_TX_DT1_BSSLAP_TA_RESPONSE));
 			break;
 		case BSSLAP_MSGT_REJECT:
-			rate_ctr_inc(&bsc_gsmnet->smlc.ctrs->ctr[SMLC_CTR_BSSMAP_LE_TX_DT1_BSSLAP_REJECT]);
+			rate_ctr_inc(rate_ctr_group_get_ctr(bsc_gsmnet->smlc->ctrs, SMLC_CTR_BSSMAP_LE_TX_DT1_BSSLAP_REJECT));
 			break;
 		case BSSLAP_MSGT_RESET:
-			rate_ctr_inc(&bsc_gsmnet->smlc.ctrs->ctr[SMLC_CTR_BSSMAP_LE_TX_DT1_BSSLAP_RESET]);
+			rate_ctr_inc(rate_ctr_group_get_ctr(bsc_gsmnet->smlc->ctrs, SMLC_CTR_BSSMAP_LE_TX_DT1_BSSLAP_RESET));
 			break;
 		case BSSLAP_MSGT_ABORT:
-			rate_ctr_inc(&bsc_gsmnet->smlc.ctrs->ctr[SMLC_CTR_BSSMAP_LE_TX_DT1_BSSLAP_ABORT]);
+			rate_ctr_inc(rate_ctr_group_get_ctr(bsc_gsmnet->smlc->ctrs, SMLC_CTR_BSSMAP_LE_TX_DT1_BSSLAP_ABORT));
 			break;
 		default:
 			break;
@@ -357,8 +352,65 @@ count_tx:
 #define DEFAULT_ASP_LOCAL_IP "localhost"
 #define DEFAULT_ASP_REMOTE_IP "localhost"
 
-/* Initialize Lb interface to SMLC */
-int lb_init()
+void lb_cancel_all(void)
+{
+	struct gsm_subscriber_connection *conn;
+	llist_for_each_entry(conn, &bsc_gsmnet->subscr_conns, entry)
+		lcs_loc_req_reset(conn);
+};
+
+void lb_reset_link_up(void *data)
+{
+	LOGP(DLCS, LOGL_INFO, "Lb link ready\n");
+}
+
+void lb_reset_link_lost(void *data)
+{
+	struct gsm_subscriber_connection *conn;
+	LOGP(DLCS, LOGL_INFO, "Lb link down\n");
+
+	/* Abort all ongoing Location Requests */
+	llist_for_each_entry(conn, &bsc_gsmnet->subscr_conns, entry)
+		lcs_loc_req_reset(conn);
+};
+
+void lb_reset_tx_reset(void *data)
+{
+	bssmap_le_tx_reset();
+}
+
+void lb_reset_tx_reset_ack(void *data)
+{
+	bssmap_le_tx_reset_ack();
+}
+
+static void lb_start_reset_fsm(void)
+{
+	struct bssmap_reset_cfg cfg = {
+		.conn_cfm_failure_threshold = 3,
+		.ops = {
+			.tx_reset = lb_reset_tx_reset,
+			.tx_reset_ack = lb_reset_tx_reset_ack,
+			.link_up = lb_reset_link_up,
+			.link_lost = lb_reset_link_lost,
+		},
+	};
+
+	if (bsc_gsmnet->smlc->bssmap_reset) {
+		LOGP(DLCS, LOGL_ERROR, "will not allocate a second reset FSM for Lb\n");
+		return;
+	}
+
+	bsc_gsmnet->smlc->bssmap_reset = bssmap_reset_alloc(bsc_gsmnet, "Lb", &cfg);
+}
+
+static void lb_stop_reset_fsm(void)
+{
+	bssmap_reset_term_and_free(bsc_gsmnet->smlc->bssmap_reset);
+	bsc_gsmnet->smlc->bssmap_reset = NULL;
+}
+
+static int lb_start(void)
 {
 	uint32_t default_pc;
 	struct osmo_ss7_instance *cs7_inst = NULL;
@@ -367,15 +419,21 @@ int lb_init()
 	char inst_name[32];
 	const char *smlc_name = "smlc";
 
-	if (!bsc_gsmnet->smlc.cs7_instance_valid) {
-		bsc_gsmnet->smlc.cs7_instance = 0;
+	/* Already set up? */
+	if (bsc_gsmnet->smlc->sccp_user)
+		return -EALREADY;
+
+	LOGP(DLCS, LOGL_INFO, "Starting Lb link\n");
+
+	if (!bsc_gsmnet->smlc->cs7_instance_valid) {
+		bsc_gsmnet->smlc->cs7_instance = 0;
 	}
-	cs7_inst = osmo_ss7_instance_find_or_create(tall_bsc_ctx, bsc_gsmnet->smlc.cs7_instance);
+	cs7_inst = osmo_ss7_instance_find_or_create(tall_bsc_ctx, bsc_gsmnet->smlc->cs7_instance);
 	OSMO_ASSERT(cs7_inst);
 
 	/* If unset, use default SCCP address for the SMLC */
-	if (!bsc_gsmnet->smlc.smlc_addr.presence)
-		osmo_sccp_make_addr_pc_ssn(&bsc_gsmnet->smlc.smlc_addr,
+	if (!bsc_gsmnet->smlc->smlc_addr.presence)
+		osmo_sccp_make_addr_pc_ssn(&bsc_gsmnet->smlc->smlc_addr,
 					   osmo_ss7_pointcode_parse(NULL, SMLC_DEFAULT_PC),
 					   OSMO_SCCP_SSN_SMLC_BSSAP_LE);
 
@@ -392,41 +450,98 @@ int lb_init()
 						 0, DEFAULT_ASP_REMOTE_IP);
 	if (!sccp)
 		return -EINVAL;
-	bsc_gsmnet->smlc.sccp = sccp;
+	bsc_gsmnet->smlc->sccp = sccp;
 
 	/* If unset, use default local SCCP address */
-	if (!bsc_gsmnet->smlc.bsc_addr.presence)
-		osmo_sccp_local_addr_by_instance(&bsc_gsmnet->smlc.bsc_addr, sccp,
+	if (!bsc_gsmnet->smlc->bsc_addr.presence)
+		osmo_sccp_local_addr_by_instance(&bsc_gsmnet->smlc->bsc_addr, sccp,
 						 OSMO_SCCP_SSN_BSC_BSSAP_LE);
 
-	if (!osmo_sccp_check_addr(&bsc_gsmnet->smlc.bsc_addr, OSMO_SCCP_ADDR_T_SSN | OSMO_SCCP_ADDR_T_PC)) {
+	if (!osmo_sccp_check_addr(&bsc_gsmnet->smlc->bsc_addr, OSMO_SCCP_ADDR_T_SSN | OSMO_SCCP_ADDR_T_PC)) {
 		LOGP(DLCS, LOGL_ERROR,
 		     "%s %s: invalid local (BSC) SCCP address: %s\n",
-		     inst_name, smlc_name, osmo_sccp_inst_addr_name(sccp, &bsc_gsmnet->smlc.bsc_addr));
+		     inst_name, smlc_name, osmo_sccp_inst_addr_name(sccp, &bsc_gsmnet->smlc->bsc_addr));
 		return -EINVAL;
 	}
 
-	if (!osmo_sccp_check_addr(&bsc_gsmnet->smlc.smlc_addr, OSMO_SCCP_ADDR_T_SSN | OSMO_SCCP_ADDR_T_PC)) {
+	if (!osmo_sccp_check_addr(&bsc_gsmnet->smlc->smlc_addr, OSMO_SCCP_ADDR_T_SSN | OSMO_SCCP_ADDR_T_PC)) {
 		LOGP(DLCS, LOGL_ERROR,
 		     "%s %s: invalid remote (SMLC) SCCP address: %s\n",
-		     inst_name, smlc_name, osmo_sccp_inst_addr_name(sccp, &bsc_gsmnet->smlc.smlc_addr));
+		     inst_name, smlc_name, osmo_sccp_inst_addr_name(sccp, &bsc_gsmnet->smlc->smlc_addr));
 		return -EINVAL;
 	}
 
 	LOGP(DLCS, LOGL_NOTICE, "Lb: %s %s: local (BSC) SCCP address: %s\n",
-	     inst_name, smlc_name, osmo_sccp_inst_addr_name(sccp, &bsc_gsmnet->smlc.bsc_addr));
+	     inst_name, smlc_name, osmo_sccp_inst_addr_name(sccp, &bsc_gsmnet->smlc->bsc_addr));
 	LOGP(DLCS, LOGL_NOTICE, "Lb: %s %s: remote (SMLC) SCCP address: %s\n",
-	     inst_name, smlc_name, osmo_sccp_inst_addr_name(sccp, &bsc_gsmnet->smlc.smlc_addr));
-
-	/* Bind SCCP user. */
-	bsc_gsmnet->smlc.sccp_user = osmo_sccp_user_find(sccp, bsc_gsmnet->smlc.bsc_addr.ssn, bsc_gsmnet->smlc.bsc_addr.pc);
-	LOGP(DLCS, LOGL_NOTICE, "%s %s: %s\n", inst_name, smlc_name,
-	     bsc_gsmnet->smlc.sccp_user ? "user already bound for this SCCP instance" : "binding SCCP user");
-	if (!bsc_gsmnet->smlc.sccp_user)
-		bsc_gsmnet->smlc.sccp_user = osmo_sccp_user_bind(sccp, smlc_name, sccp_sap_up, bsc_gsmnet->smlc.bsc_addr.ssn);
-	if (!bsc_gsmnet->smlc.sccp_user)
+	     inst_name, smlc_name, osmo_sccp_inst_addr_name(sccp, &bsc_gsmnet->smlc->smlc_addr));
+
+	bsc_gsmnet->smlc->sccp_user = osmo_sccp_user_bind(sccp, smlc_name, sccp_sap_up, bsc_gsmnet->smlc->bsc_addr.ssn);
+	if (!bsc_gsmnet->smlc->sccp_user)
 		return -EINVAL;
 
+	lb_start_reset_fsm();
+	return 0;
+}
+
+static int lb_stop(void)
+{
+	/* Not set up? */
+	if (!bsc_gsmnet->smlc->sccp_user)
+		return -EALREADY;
+
+	LOGP(DLCS, LOGL_INFO, "Shutting down Lb link\n");
+
+	lb_cancel_all();
+	lb_stop_reset_fsm();
+	osmo_sccp_user_unbind(bsc_gsmnet->smlc->sccp_user);
+	bsc_gsmnet->smlc->sccp_user = NULL;
+	return 0;
+}
+
+int lb_start_or_stop(void)
+{
+	int rc;
+	if (bsc_gsmnet->smlc->enable) {
+		rc = lb_start();
+		switch (rc) {
+		case 0:
+			/* all is fine */
+			break;
+		case -EALREADY:
+			/* no need to log about anything */
+			break;
+		default:
+			LOGP(DLCS, LOGL_ERROR, "Failed to start Lb interface (rc=%d)\n", rc);
+			break;
+		}
+	} else {
+		rc = lb_stop();
+		switch (rc) {
+		case 0:
+			/* all is fine */
+			break;
+		case -EALREADY:
+			/* no need to log about anything */
+			break;
+		default:
+			LOGP(DLCS, LOGL_ERROR, "Failed to stop Lb interface (rc=%d)\n", rc);
+			break;
+		}
+	}
+	return rc;
+}
+
+static void smlc_vty_init(void);
+
+int lb_init(void)
+{
+	OSMO_ASSERT(!bsc_gsmnet->smlc);
+	bsc_gsmnet->smlc = talloc_zero(bsc_gsmnet, struct smlc_config);
+	OSMO_ASSERT(bsc_gsmnet->smlc);
+	bsc_gsmnet->smlc->ctrs = rate_ctr_group_alloc(bsc_gsmnet, &smlc_ctrg_desc, 0);
+
+	smlc_vty_init();
 	return 0;
 }
 
@@ -447,6 +562,30 @@ static struct cmd_node smlc_node = {
 	1,
 };
 
+DEFUN(cfg_smlc_enable, cfg_smlc_enable_cmd,
+	"enable",
+	"Start up Lb interface connection to the remote SMLC\n")
+{
+	bsc_gsmnet->smlc->enable = true;
+	if (vty->type != VTY_FILE) {
+		if (lb_start_or_stop())
+			vty_out(vty, "%% Error: failed to enable Lb interface%s", VTY_NEWLINE);
+	}
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_smlc_no_enable, cfg_smlc_no_enable_cmd,
+	"no enable",
+	NO_STR "Stop Lb interface connection to the remote SMLC\n")
+{
+	bsc_gsmnet->smlc->enable = false;
+	if (vty->type != VTY_FILE) {
+		if (lb_start_or_stop())
+			vty_out(vty, "%% Error: failed to disable Lb interface%s", VTY_NEWLINE);
+	}
+	return CMD_SUCCESS;
+}
+
 static void enforce_ssn(struct vty *vty, struct osmo_sccp_addr *addr, enum osmo_sccp_ssn want_ssn)
 {
 	if (addr->presence & OSMO_SCCP_ADDR_T_SSN) {
@@ -460,6 +599,28 @@ static void enforce_ssn(struct vty *vty, struct osmo_sccp_addr *addr, enum osmo_
 	addr->ssn = want_ssn;
 }
 
+/* Prevent mixing addresses from different CS7 instances */
+bool smlc_set_cs7_instance(struct vty *vty, const char *from_vty_cmd, const char *from_addr,
+			   struct osmo_ss7_instance *ss7)
+{
+	if (bsc_gsmnet->smlc->cs7_instance_valid) {
+		if (bsc_gsmnet->smlc->cs7_instance != ss7->cfg.id) {
+			LOGP(DLCS, LOGL_ERROR,
+			     "%s: expecting address from cs7 instance %u, but '%s' is from %u\n",
+			     from_vty_cmd, bsc_gsmnet->smlc->cs7_instance, from_addr, ss7->cfg.id);
+			vty_out(vty, "Error:"
+				" %s: expecting address from cs7 instance %u, but '%s' is from %u%s",
+				from_vty_cmd, bsc_gsmnet->smlc->cs7_instance, from_addr, ss7->cfg.id, VTY_NEWLINE);
+			return false;
+		}
+	} else {
+		bsc_gsmnet->smlc->cs7_instance = ss7->cfg.id;
+		bsc_gsmnet->smlc->cs7_instance_valid = true;
+		LOGP(DLCS, LOGL_NOTICE, "Lb interface is using cs7 instance %u\n", bsc_gsmnet->smlc->cs7_instance);
+	}
+	return true;
+}
+
 DEFUN(cfg_smlc_cs7_bsc_addr,
       cfg_smlc_cs7_bsc_addr_cmd,
       "bsc-addr NAME",
@@ -468,25 +629,17 @@ DEFUN(cfg_smlc_cs7_bsc_addr,
 	const char *bsc_addr_name = argv[0];
 	struct osmo_ss7_instance *ss7;
 
-	ss7 = osmo_sccp_addr_by_name(&bsc_gsmnet->smlc.bsc_addr, bsc_addr_name);
+	ss7 = osmo_sccp_addr_by_name(&bsc_gsmnet->smlc->bsc_addr, bsc_addr_name);
 	if (!ss7) {
 		vty_out(vty, "Error: No such SCCP addressbook entry: '%s'%s", bsc_addr_name, VTY_NEWLINE);
 		return CMD_ERR_INCOMPLETE;
 	}
 
-	/* Prevent mixing addresses from different CS7 instances */
-	if (bsc_gsmnet->smlc.cs7_instance_valid
-	    && bsc_gsmnet->smlc.cs7_instance != ss7->cfg.id) {
-		vty_out(vty,
-			"Error: SCCP addressbook entry from mismatching CS7 instance: '%s'%s",
-			bsc_addr_name, VTY_NEWLINE);
+	if (!smlc_set_cs7_instance(vty, "smlc / bsc-addr", bsc_addr_name, ss7))
 		return CMD_WARNING;
-	}
 
-	bsc_gsmnet->smlc.cs7_instance = ss7->cfg.id;
-	bsc_gsmnet->smlc.cs7_instance_valid = true;
-	enforce_ssn(vty, &bsc_gsmnet->smlc.bsc_addr, OSMO_SCCP_SSN_BSC_BSSAP_LE);
-	bsc_gsmnet->smlc.bsc_addr_name = talloc_strdup(bsc_gsmnet, bsc_addr_name);
+	enforce_ssn(vty, &bsc_gsmnet->smlc->bsc_addr, OSMO_SCCP_SSN_BSC_BSSAP_LE);
+	bsc_gsmnet->smlc->bsc_addr_name = talloc_strdup(bsc_gsmnet, bsc_addr_name);
 	return CMD_SUCCESS;
 }
 
@@ -498,39 +651,40 @@ DEFUN(cfg_smlc_cs7_smlc_addr,
 	const char *smlc_addr_name = argv[0];
 	struct osmo_ss7_instance *ss7;
 
-	ss7 = osmo_sccp_addr_by_name(&bsc_gsmnet->smlc.smlc_addr, smlc_addr_name);
+	ss7 = osmo_sccp_addr_by_name(&bsc_gsmnet->smlc->smlc_addr, smlc_addr_name);
 	if (!ss7) {
 		vty_out(vty, "Error: No such SCCP addressbook entry: '%s'%s", smlc_addr_name, VTY_NEWLINE);
 		return CMD_ERR_INCOMPLETE;
 	}
 
-	/* Prevent mixing addresses from different CS7/SS7 instances */
-	if (bsc_gsmnet->smlc.cs7_instance_valid) {
-		if (bsc_gsmnet->smlc.cs7_instance != ss7->cfg.id) {
-			vty_out(vty,
-				"Error: SCCP addressbook entry from mismatching CS7 instance: '%s'%s",
-				smlc_addr_name, VTY_NEWLINE);
-			return CMD_ERR_INCOMPLETE;
-		}
-	}
+	if (!smlc_set_cs7_instance(vty, "smlc / smlc-addr", smlc_addr_name, ss7))
+		return CMD_WARNING;
 
-	bsc_gsmnet->smlc.cs7_instance = ss7->cfg.id;
-	bsc_gsmnet->smlc.cs7_instance_valid = true;
-	enforce_ssn(vty, &bsc_gsmnet->smlc.smlc_addr, OSMO_SCCP_SSN_SMLC_BSSAP_LE);
-	bsc_gsmnet->smlc.smlc_addr_name = talloc_strdup(bsc_gsmnet, smlc_addr_name);
+	enforce_ssn(vty, &bsc_gsmnet->smlc->smlc_addr, OSMO_SCCP_SSN_SMLC_BSSAP_LE);
+	bsc_gsmnet->smlc->smlc_addr_name = talloc_strdup(bsc_gsmnet, smlc_addr_name);
 	return CMD_SUCCESS;
 }
 
 static int config_write_smlc(struct vty *vty)
 {
+	/* Nothing to write? */
+	if (!(bsc_gsmnet->smlc->enable
+	      || bsc_gsmnet->smlc->bsc_addr_name
+	      || bsc_gsmnet->smlc->smlc_addr_name))
+		return 0;
+
 	vty_out(vty, "smlc%s", VTY_NEWLINE);
-	if (bsc_gsmnet->smlc.bsc_addr_name) {
+
+	if (bsc_gsmnet->smlc->enable)
+		vty_out(vty, " enable%s", VTY_NEWLINE);
+
+	if (bsc_gsmnet->smlc->bsc_addr_name) {
 		vty_out(vty, " bsc-addr %s%s",
-			bsc_gsmnet->smlc.bsc_addr_name, VTY_NEWLINE);
+			bsc_gsmnet->smlc->bsc_addr_name, VTY_NEWLINE);
 	}
-	if (bsc_gsmnet->smlc.smlc_addr_name) {
+	if (bsc_gsmnet->smlc->smlc_addr_name) {
 		vty_out(vty, " smlc-addr %s%s",
-			bsc_gsmnet->smlc.smlc_addr_name, VTY_NEWLINE);
+			bsc_gsmnet->smlc->smlc_addr_name, VTY_NEWLINE);
 	}
 
 	return 0;
@@ -550,6 +704,8 @@ void smlc_vty_init(void)
 
 	install_element(CONFIG_NODE, &cfg_smlc_cmd);
 	install_node(&smlc_node, config_write_smlc);
+	install_element(SMLC_NODE, &cfg_smlc_enable_cmd);
+	install_element(SMLC_NODE, &cfg_smlc_no_enable_cmd);
 	install_element(SMLC_NODE, &cfg_smlc_cs7_bsc_addr_cmd);
 	install_element(SMLC_NODE, &cfg_smlc_cs7_smlc_addr_cmd);
 }