WIP: Port to new libosmo-sigtran API (with proper M3UA for Iuh)

This changes over to the new libosmo-sigtran API with support for
proper SCCP/M3UA/SCTP stacking, as mandated by 3GPP specifications for
the IuCS and IuPS interfaces.

Only the ASP (client) is used, assuming that both the HNB-GWs and RNCs
as well as the MSCs and SGSNs are all connecting as ASP to some STP/SGW
which offers M3UA server functionality as well as point-code and/or
global title based routing.

Tweaked-by: nhofmeyr (test expectation)
Change-Id: If0ff956fbf1484899d59ae1a5885543bca31645b
diff --git a/openbsc/include/openbsc/iu.h b/openbsc/include/openbsc/iu.h
index 0ef2f82..0cc16d0 100644
--- a/openbsc/include/openbsc/iu.h
+++ b/openbsc/include/openbsc/iu.h
@@ -5,13 +5,15 @@
 
 #include <osmocom/core/linuxlist.h>
 #include <osmocom/gsm/gsm48.h>
+#include <osmocom/sigtran/sccp_sap.h>
 
 #include <openbsc/common.h>
 
 struct sgsn_pdp_ctx;
 struct msgb;
-struct osmo_sccp_link;
 struct gsm_auth_tuple;
+struct osmo_sccp_addr;
+struct osmo_ss7_instance;
 
 struct RANAP_RAB_SetupOrModifiedItemIEs_s;
 struct RANAP_GlobalRNC_ID;
@@ -23,7 +25,10 @@
 
 struct ue_conn_ctx {
 	struct llist_head list;
-	struct osmo_sccp_link *link;
+	/* TODO: It's not needed to store the full SCCP address for each
+	 * UE.  Rather than that, a pointer to the RNC should be far
+	 * sufficient */
+	struct osmo_sccp_addr sccp_addr;
 	uint32_t conn_id;
 	int integrity_active;
 	struct gprs_ra_id ra_id;
@@ -57,11 +62,10 @@
 typedef int (* iu_rab_ass_resp_cb_t )(struct ue_conn_ctx *ue_ctx, uint8_t rab_id,
 		struct RANAP_RAB_SetupOrModifiedItemIEs_s *setup_ies);
 
-int iu_init(void *ctx, const char *listen_addr, uint16_t listen_port,
+int iu_init(void *ctx, const char *name, uint32_t local_pc, const char *listen_addr,
+	    const char *remote_addr, uint16_t local_port,
 	    iu_recv_cb_t iu_recv_cb, iu_event_cb_t iu_event_cb);
 
-void iu_link_del(struct osmo_sccp_link *link);
-
 int iu_tx(struct msgb *msg, uint8_t sapi);
 
 int iu_page_cs(const char *imsi, const uint32_t *tmsi, uint16_t lac);
diff --git a/openbsc/src/gprs/sgsn_main.c b/openbsc/src/gprs/sgsn_main.c
index f2f1344..3318d66 100644
--- a/openbsc/src/gprs/sgsn_main.c
+++ b/openbsc/src/gprs/sgsn_main.c
@@ -431,7 +431,7 @@
 	}
 
 #ifdef BUILD_IU
-	iu_init(tall_bsc_ctx, "127.0.0.2", 14001, gsm0408_gprs_rcvmsg_iu, sgsn_ranap_iu_event);
+	iu_init(tall_bsc_ctx, "OsmoSGSN", 2, "127.0.0.4", "127.0.0.1", 0, gsm0408_gprs_rcvmsg_iu, sgsn_ranap_iu_event);
 #endif
 
 	if (daemonize) {
diff --git a/openbsc/src/libiu/iu.c b/openbsc/src/libiu/iu.c
index 5d56a4a..32891f9 100644
--- a/openbsc/src/libiu/iu.c
+++ b/openbsc/src/libiu/iu.c
@@ -36,9 +36,10 @@
 #include <osmocom/gsm/gsm48.h>
 #include <osmocom/gprs/gprs_msgb.h>
 
-#include <osmocom/sigtran/sua.h>
+#include <osmocom/sigtran/osmo_ss7.h>
 #include <osmocom/sigtran/sccp_sap.h>
 #include <osmocom/sigtran/sccp_helpers.h>
+#include <osmocom/sigtran/protocol/m3ua.h>
 
 #include <openbsc/gprs_sgsn.h>
 #include <openbsc/iu.h>
@@ -63,7 +64,7 @@
 };
 
 /* A remote RNC (Radio Network Controller, like BSC but for UMTS) that has
- * called us and is currently reachable at the given osmo_sccp_link. So, when we
+ * called us and is currently reachable at the given osmo_sccp_addr. So, when we
  * know a LAC for a subscriber, we can page it at the RNC matching that LAC or
  * RAC. An HNB-GW typically presents itself as if it were a single RNC, even
  * though it may have several RNCs in hNodeBs connected to it. Those will then
@@ -75,7 +76,7 @@
 	uint16_t rnc_id;
 	uint16_t lac; /* Location Area Code (used for CS and PS) */
 	uint8_t rac; /* Routing Area Code (used for PS only) */
-	struct osmo_sccp_link *link;
+	struct osmo_sccp_addr sccp_addr;
 };
 
 void *talloc_iu_ctx;
@@ -97,6 +98,9 @@
 static LLIST_HEAD(ue_conn_ctx_list);
 static LLIST_HEAD(rnc_list);
 
+static struct osmo_sccp_instance *g_sccp;
+static struct osmo_sccp_user *g_scu;
+
 const struct value_string iu_event_type_names[] = {
 	OSMO_VALUE_STRING(IU_EVENT_RAB_ASSIGN),
 	OSMO_VALUE_STRING(IU_EVENT_SECURITY_MODE_COMPLETE),
@@ -105,38 +109,37 @@
 	{ 0, NULL }
 };
 
-struct ue_conn_ctx *ue_conn_ctx_alloc(struct osmo_sccp_link *link, uint32_t conn_id)
+struct ue_conn_ctx *ue_conn_ctx_alloc(struct osmo_sccp_addr *addr, uint32_t conn_id)
 {
 	struct ue_conn_ctx *ctx = talloc_zero(talloc_iu_ctx, struct ue_conn_ctx);
 
-	ctx->link = link;
+	ctx->sccp_addr = *addr;
 	ctx->conn_id = conn_id;
 	llist_add(&ctx->list, &ue_conn_ctx_list);
 
 	return ctx;
 }
 
-struct ue_conn_ctx *ue_conn_ctx_find(struct osmo_sccp_link *link,
-				     uint32_t conn_id)
+struct ue_conn_ctx *ue_conn_ctx_find(uint32_t conn_id)
 {
 	struct ue_conn_ctx *ctx;
 
 	llist_for_each_entry(ctx, &ue_conn_ctx_list, list) {
-		if (ctx->link == link && ctx->conn_id == conn_id)
+		if (ctx->conn_id == conn_id)
 			return ctx;
 	}
 	return NULL;
 }
 
 static struct iu_rnc *iu_rnc_alloc(uint16_t rnc_id, uint16_t lac, uint8_t rac,
-				   struct osmo_sccp_link *link)
+				   struct osmo_sccp_addr *addr)
 {
 	struct iu_rnc *rnc = talloc_zero(talloc_iu_ctx, struct iu_rnc);
 
 	rnc->rnc_id = rnc_id;
 	rnc->lac = lac;
 	rnc->rac = rac;
-	rnc->link = link;
+	rnc->sccp_addr = *addr;
 	llist_add(&rnc->entry, &rnc_list);
 
 	LOGP(DRANAP, LOGL_NOTICE, "New RNC %d (LAC=%d RAC=%d)\n",
@@ -146,7 +149,7 @@
 }
 
 static struct iu_rnc *iu_rnc_register(uint16_t rnc_id, uint16_t lac,
-				      uint8_t rac, struct osmo_sccp_link *link)
+				      uint8_t rac, struct osmo_sccp_addr *addr)
 {
 	struct iu_rnc *rnc;
 	llist_for_each_entry(rnc, &rnc_list, entry) {
@@ -165,42 +168,16 @@
 		rnc->lac = lac;
 		rnc->rac = rac;
 
-		if (link && rnc->link != link)
-			LOGP(DRANAP, LOGL_NOTICE, "RNC %d on new link"
+		if (addr && memcmp(&rnc->sccp_addr, addr, sizeof(*addr)))
+			LOGP(DRANAP, LOGL_NOTICE, "RNC %d on New SCCP Addr %s"
 			     " (LAC=%d RAC=%d)\n",
-			     rnc->rnc_id, rnc->lac, rnc->rac);
-		rnc->link = link;
+			     rnc->rnc_id, osmo_sccp_addr_dump(addr), rnc->lac, rnc->rac);
+		rnc->sccp_addr = *addr;
 		return rnc;
 	}
 
 	/* Not found, make a new one. */
-	return iu_rnc_alloc(rnc_id, lac, rac, link);
-}
-
-/* Discard/invalidate all ue_conn_ctx and iu_rnc entries that reference the
- * given link, since this link is invalid and about to be deallocated. For
- * each ue_conn_ctx, invoke the iu_event_cb_t with IU_EVENT_LINK_INVALIDATED.
- */
-void iu_link_del(struct osmo_sccp_link *link)
-{
-	struct iu_rnc *rnc, *rnc_next;
-	llist_for_each_entry_safe(rnc, rnc_next, &rnc_list, entry) {
-		if (!rnc->link)
-			continue;
-		if (rnc->link != link)
-			continue;
-		rnc->link = NULL;
-		llist_del(&rnc->entry);
-		talloc_free(rnc);
-	}
-
-	struct ue_conn_ctx *uec, *uec_next;
-	llist_for_each_entry_safe(uec, uec_next, &ue_conn_ctx_list, list) {
-		if (uec->link != link)
-			continue;
-		uec->link = NULL;
-		global_iu_event_cb(uec, IU_EVENT_LINK_INVALIDATED, NULL);
-	}
+	return iu_rnc_alloc(rnc_id, lac, rac, addr);
 }
 
 /***********************************************************************
@@ -219,7 +196,7 @@
 		       OSMO_SCU_PRIM_N_DATA,
 		       PRIM_OP_REQUEST,
 		       msg);
-	return osmo_sua_user_link_down(ue_ctx->link, &prim->oph);
+	return osmo_sccp_user_sap_down(g_scu, &prim->oph);
 }
 
 int iu_rab_deact(struct ue_conn_ctx *ue_ctx, uint8_t rab_id)
@@ -244,7 +221,7 @@
 	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
 			OSMO_SCU_PRIM_N_DATA,
 			PRIM_OP_REQUEST, msg);
-	osmo_sua_user_link_down(uectx->link, &prim->oph);
+	osmo_sccp_user_sap_down(g_scu, &prim->oph);
 
 	return 0;
 }
@@ -254,8 +231,8 @@
 	struct msgb *msg;
 	struct osmo_scu_prim *prim;
 
-	LOGP(DRANAP, LOGL_INFO, "Transmitting RANAP CommonID (SUA link %p conn_id %u)\n",
-	     uectx->link, uectx->conn_id);
+	LOGP(DRANAP, LOGL_INFO, "Transmitting RANAP CommonID (SCCP conn_id %u)\n",
+	     uectx->conn_id);
 
 	msg = ranap_new_msg_common_id(imsi);
 	msg->l2h = msg->data;
@@ -264,7 +241,7 @@
 	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
 			OSMO_SCU_PRIM_N_DATA,
 			PRIM_OP_REQUEST, msg);
-	osmo_sua_user_link_down(uectx->link, &prim->oph);
+	osmo_sccp_user_sap_down(g_scu, &prim->oph);
 	return 0;
 }
 
@@ -325,7 +302,7 @@
 	memcpy(msgb_gmmh(msg), ies->nas_pdu.buf, ies->nas_pdu.size);
 
 	/* Make sure we know the RNC Id and LAC+RAC coming in on this connection. */
-	iu_rnc_register(grnc_id.rnc_id, ra_id.lac, ra_id.rac, ue_conn->link);
+	iu_rnc_register(grnc_id.rnc_id, ra_id.lac, ra_id.rac, &ue_conn->sccp_addr);
 	ue_conn->ra_id = ra_id;
 
 	/* Feed into the MM layer */
@@ -387,8 +364,8 @@
 	struct msgb *msg;
 	struct osmo_scu_prim *prim;
 
-	LOGP(DRANAP, LOGL_INFO, "Transmitting L3 Message as RANAP DT (SUA link %p conn_id %u)\n",
-	     uectx->link, uectx->conn_id);
+	LOGP(DRANAP, LOGL_INFO, "Transmitting L3 Message as RANAP DT (SCCP conn_id %u)\n",
+	     uectx->conn_id);
 
 	msg = ranap_new_msg_dt(sapi, msg_nas->data, msgb_length(msg_nas));
 	msgb_free(msg_nas);
@@ -398,7 +375,7 @@
 	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
 			OSMO_SCU_PRIM_N_DATA,
 			PRIM_OP_REQUEST, msg);
-	osmo_sua_user_link_down(uectx->link, &prim->oph);
+	osmo_sccp_user_sap_down(g_scu, &prim->oph);
 	return 0;
 }
 
@@ -424,7 +401,7 @@
 	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
 			OSMO_SCU_PRIM_N_DATA,
 			PRIM_OP_REQUEST, msg);
-	return osmo_sua_user_link_down(ctx->link, &prim->oph);
+	return osmo_sccp_user_sap_down(g_scu, &prim->oph);
 }
 
 static int ranap_handle_co_iu_rel_req(struct ue_conn_ctx *ctx, RANAP_Iu_ReleaseRequestIEs_t *ies)
@@ -595,21 +572,28 @@
  * Paging
  ***********************************************************************/
 
-/* Send a paging command down a given SUA link. tmsi and paging_cause are
+struct osmo_sccp_addr local_sccp_addr = {
+	.presence = OSMO_SCCP_ADDR_T_SSN | OSMO_SCCP_ADDR_T_PC,
+	.ri = OSMO_SCCP_RI_SSN_PC,
+	.ssn = OSMO_SCCP_SSN_RANAP,
+	.pc = 1,
+};
+
+/* Send a paging command down a given SCCP User. tmsi and paging_cause are
  * optional and may be passed NULL and 0, respectively, to disable their use.
  * See enum RANAP_PagingCause.
  *
  * If TMSI is given, the IMSI is not sent over the air interface. Nevertheless,
  * the IMSI is still required for resolution in the HNB-GW and/or(?) RNC. */
-static int iu_tx_paging_cmd(struct osmo_sccp_link *link,
+static int iu_tx_paging_cmd(struct osmo_sccp_addr *called_addr,
 			    const char *imsi, const uint32_t *tmsi,
 			    bool is_ps, uint32_t paging_cause)
 {
 	struct msgb *msg;
 	msg = ranap_new_msg_paging_cmd(imsi, tmsi, is_ps? 1 : 0, paging_cause);
 	msg->l2h = msg->data;
-	return osmo_sccp_tx_unitdata_ranap(link, 1, 2, msg->data,
-					   msgb_length(msg));
+	osmo_sccp_tx_unitdata_msg(g_scu, &local_sccp_addr, called_addr, msg);
+	return 0;
 }
 
 static int iu_page(const char *imsi, const uint32_t *tmsi_or_ptimsi,
@@ -634,22 +618,18 @@
 	}
 
 	llist_for_each_entry(rnc, &rnc_list, entry) {
-		if (!rnc->link) {
-			/* Not actually connected, don't count it. */
-			continue;
-		}
 		if (rnc->lac != lac)
 			continue;
 		if (is_ps && rnc->rac != rac)
 			continue;
 
 		/* Found a match! */
-		if (iu_tx_paging_cmd(rnc->link, imsi, tmsi_or_ptimsi, is_ps, 0)
+		if (iu_tx_paging_cmd(&rnc->sccp_addr, imsi, tmsi_or_ptimsi, is_ps, 0)
 		    == 0) {
 			LOGP(DRANAP, LOGL_DEBUG,
-			     "%s: Paged for IMSI %s on RNC %d, on SUA link %p\n",
+			     "%s: Paged for IMSI %s on RNC %d, on SCCP addr %s\n",
 			     is_ps? "IuPS" : "IuCS",
-			     imsi, rnc->rnc_id, rnc->link);
+			     imsi, rnc->rnc_id, osmo_sccp_addr_dump(&rnc->sccp_addr));
 			pagings_sent ++;
 		}
 	}
@@ -692,8 +672,8 @@
  *
  ***********************************************************************/
 
-int tx_unitdata(struct osmo_sccp_link *link);
-int tx_conn_req(struct osmo_sccp_link *link, uint32_t conn_id);
+int tx_unitdata(struct osmo_sccp_user *scu);
+int tx_conn_req(struct osmo_sccp_user *scu, uint32_t conn_id);
 
 struct osmo_prim_hdr *make_conn_req(uint32_t conn_id);
 struct osmo_prim_hdr *make_dt1_req(uint32_t conn_id, const uint8_t *data, unsigned int len);
@@ -711,8 +691,9 @@
 	return &prim->oph;
 }
 
-static int sccp_sap_up(struct osmo_prim_hdr *oph, void *link)
+static int sccp_sap_up(struct osmo_prim_hdr *oph, void *_scu)
 {
+	struct osmo_sccp_user *scu = _scu;
 	struct osmo_scu_prim *prim = (struct osmo_scu_prim *) oph;
 	struct osmo_prim_hdr *resp = NULL;
 	int rc;
@@ -734,10 +715,10 @@
 			     "Received invalid N-CONNECT.ind\n");
 			return 0;
 		}
-		ue = ue_conn_ctx_alloc(link, prim->u.connect.conn_id);
-		/* first ensure the local SUA/SCCP socket is ACTIVE */
+		ue = ue_conn_ctx_alloc(&prim->u.connect.calling_addr, prim->u.connect.conn_id);
+		/* first ensure the local SCCP socket is ACTIVE */
 		resp = make_conn_resp(&prim->u.connect);
-		osmo_sua_user_link_down(link, resp);
+		osmo_sccp_user_sap_down(scu, resp);
 		/* then handle the RANAP payload */
 		rc = ranap_cn_rx_co(cn_ranap_handle_co, ue, msgb_l2(oph->msg), msgb_l2len(oph->msg));
 		break;
@@ -745,7 +726,7 @@
 		/* indication of disconnect */
 		DEBUGP(DRANAP, "N-DISCONNECT.ind(%u)\n",
 		       prim->u.disconnect.conn_id);
-		ue = ue_conn_ctx_find(link, prim->u.disconnect.conn_id);
+		ue = ue_conn_ctx_find(prim->u.disconnect.conn_id);
 		rc = ranap_cn_rx_co(cn_ranap_handle_co, ue, msgb_l2(oph->msg), msgb_l2len(oph->msg));
 		break;
 	case OSMO_PRIM(OSMO_SCU_PRIM_N_DATA, PRIM_OP_INDICATION):
@@ -753,14 +734,14 @@
 		DEBUGP(DRANAP, "N-DATA.ind(%u, %s)\n", prim->u.data.conn_id,
 		       osmo_hexdump(msgb_l2(oph->msg), msgb_l2len(oph->msg)));
 		/* resolve UE context */
-		ue = ue_conn_ctx_find(link, prim->u.data.conn_id);
+		ue = ue_conn_ctx_find(prim->u.data.conn_id);
 		rc = ranap_cn_rx_co(cn_ranap_handle_co, ue, msgb_l2(oph->msg), msgb_l2len(oph->msg));
 		break;
 	case OSMO_PRIM(OSMO_SCU_PRIM_N_UNITDATA, PRIM_OP_INDICATION):
 		/* connection-less data received */
 		DEBUGP(DRANAP, "N-UNITDATA.ind(%s)\n",
 		       osmo_hexdump(msgb_l2(oph->msg), msgb_l2len(oph->msg)));
-		rc = ranap_cn_rx_cl(cn_ranap_handle_cl, link, msgb_l2(oph->msg), msgb_l2len(oph->msg));
+		rc = ranap_cn_rx_cl(cn_ranap_handle_cl, scu, msgb_l2(oph->msg), msgb_l2len(oph->msg));
 		break;
 	default:
 		rc = -1;
@@ -771,17 +752,19 @@
 	return rc;
 }
 
-int iu_init(void *ctx, const char *listen_addr, uint16_t listen_port,
+int iu_init(void *ctx, const char *name, uint32_t local_pc, const char *listen_addr,
+	    const char *remote_addr, uint16_t local_port,
 	    iu_recv_cb_t iu_recv_cb, iu_event_cb_t iu_event_cb)
 {
-	struct osmo_sccp_user *user;
 	talloc_iu_ctx = talloc_named_const(ctx, 1, "iu");
 	talloc_asn1_ctx = talloc_named_const(talloc_iu_ctx, 1, "asn1");
 
 	global_iu_recv_cb = iu_recv_cb;
 	global_iu_event_cb = iu_event_cb;
-	osmo_sua_set_log_area(DSUA);
-	user = osmo_sua_user_create(talloc_iu_ctx, sccp_sap_up, talloc_iu_ctx);
-	return osmo_sua_server_listen(user, listen_addr, listen_port);
+	g_sccp = osmo_sccp_simple_client(talloc_iu_ctx, name, local_pc, OSMO_SS7_ASP_PROT_M3UA,
+					 local_port, listen_addr, M3UA_PORT, remote_addr);
+	g_scu = osmo_sccp_user_bind(g_sccp, name, sccp_sap_up, OSMO_SCCP_SSN_RANAP);
+
+	return 0;
 }
 
diff --git a/openbsc/src/libiu/iu_vty.c b/openbsc/src/libiu/iu_vty.c
index 73ad126..0b42e34 100644
--- a/openbsc/src/libiu/iu_vty.c
+++ b/openbsc/src/libiu/iu_vty.c
@@ -23,6 +23,8 @@
 #include <osmocom/core/logging.h>
 #include <osmocom/vty/command.h>
 #include <osmocom/vty/logging.h>
+#include <osmocom/sigtran/osmo_ss7.h>
+#include <osmocom/sigtran/sccp_sap.h>
 
 #include <openbsc/iu.h>
 
@@ -52,9 +54,10 @@
 	return CMD_SUCCESS;
 }
 
+#define IU_STR "Iu interface protocol options\n"
 DEFUN(cfg_iu_rab_assign_addr_enc, cfg_iu_rab_assign_addr_enc_cmd,
       "iu rab-assign-addr-enc (x213|v4raw)",
-      "Iu interface protocol options\n"
+      IU_STR
       "Choose RAB Assignment's Transport Layer Address encoding\n"
       "ITU-T X.213 compliant address encoding (default)\n"
       "32bit length raw IPv4 address (for ip.access nano3G)\n")
@@ -72,6 +75,21 @@
 	return CMD_SUCCESS;
 }
 
+extern struct osmo_sccp_addr local_sccp_addr;
+
+DEFUN(cfg_iu_local_addr_pc, cfg_iu_local_addr_pc_cmd,
+	"iu local-address point-code PC",
+	IU_STR "Local SCCP Address\n")
+{
+	local_sccp_addr.presence = OSMO_SCCP_ADDR_T_PC | OSMO_SCCP_ADDR_T_SSN;
+	local_sccp_addr.ri = OSMO_SCCP_RI_SSN_PC;
+	local_sccp_addr.pc = osmo_ss7_pointcode_parse(NULL, argv[0]);
+
+	return CMD_SUCCESS;
+}
+
+/* TODO: GT address configuration, in line with 4.5.1.1.1 of TS 25.410 */
+
 int iu_vty_config_write(struct vty *vty, const char *indent)
 {
 	if (!g_rab_assign_addr_enc) {
@@ -95,6 +113,9 @@
 		return CMD_WARNING;
 	}
 
+	vty_out(vty, "%siu local-address point-code %s%s", indent,
+		osmo_ss7_pointcode_print(NULL, local_sccp_addr.pc), VTY_NEWLINE);
+
 	return CMD_SUCCESS;
 }
 
@@ -105,4 +126,5 @@
 	install_element(CFG_LOG_NODE, &logging_asn_debug_cmd);
 	install_element(CFG_LOG_NODE, &logging_asn_xer_print_cmd);
 	install_element(iu_parent_node, &cfg_iu_rab_assign_addr_enc_cmd);
+	install_element(iu_parent_node, &cfg_iu_local_addr_pc_cmd);
 }
diff --git a/openbsc/src/libmsc/iucs.c b/openbsc/src/libmsc/iucs.c
index aeda140..be026c8 100644
--- a/openbsc/src/libmsc/iucs.c
+++ b/openbsc/src/libmsc/iucs.c
@@ -40,8 +40,8 @@
 {
 	struct gsm_subscriber_connection *conn;
 
-	DEBUGP(DIUCS, "Allocating IuCS subscriber conn: lac %d, link_id %p, conn_id %" PRIx32 "\n",
-	       lac, ue->link, ue->conn_id);
+	DEBUGP(DIUCS, "Allocating IuCS subscriber conn: lac %d, conn_id %" PRIx32 "\n",
+	       lac, ue->conn_id);
 
 	conn = talloc_zero(network, struct gsm_subscriber_connection);
 	if (!conn)
@@ -61,8 +61,7 @@
 {
 	if (a == b)
 		return 1;
-	return (a->link == b->link)
-		&& (a->conn_id == b->conn_id);
+	return (a->conn_id == b->conn_id);
 }
 
 static inline void log_subscribers(struct gsm_network *network)
@@ -78,8 +77,7 @@
 		case RAN_UTRAN_IU:
 			DEBUGPC(DIUCS, " Iu");
 			if (conn->iu.ue_ctx) {
-				DEBUGPC(DIUCS, " link %p, conn_id %d",
-					conn->iu.ue_ctx->link,
+				DEBUGPC(DIUCS, " conn_id %d",
 					conn->iu.ue_ctx->conn_id
 				       );
 			}
@@ -101,7 +99,7 @@
 	DEBUGP(DIUCS, "subscribers registered: %d\n", i);
 }
 
-/* Return an existing IuCS subscriber connection record for the given link and
+/* Return an existing IuCS subscriber connection record for the given
  * connection IDs, or return NULL if not found. */
 struct gsm_subscriber_connection *subscr_conn_lookup_iu(
 						struct gsm_network *network,
@@ -109,8 +107,8 @@
 {
 	struct gsm_subscriber_connection *conn;
 
-	DEBUGP(DIUCS, "Looking for IuCS subscriber: link_id %p, conn_id %" PRIx32 "\n",
-	       ue->link, ue->conn_id);
+	DEBUGP(DIUCS, "Looking for IuCS subscriber: conn_id %" PRIx32 "\n",
+	       ue->conn_id);
 	log_subscribers(network);
 
 	llist_for_each_entry(conn, &network->subscr_conns, entry) {
@@ -118,12 +116,12 @@
 			continue;
 		if (!same_ue_conn(conn->iu.ue_ctx, ue))
 			continue;
-		DEBUGP(DIUCS, "Found IuCS subscriber for link_id %p, conn_id %" PRIx32 "\n",
-		       ue->link, ue->conn_id);
+		DEBUGP(DIUCS, "Found IuCS subscriber for conn_id %" PRIx32 "\n",
+		       ue->conn_id);
 		return conn;
 	}
-	DEBUGP(DIUCS, "No IuCS subscriber found for link_id %p, conn_id %" PRIx32 "\n",
-	       ue->link, ue->conn_id);
+	DEBUGP(DIUCS, "No IuCS subscriber found for conn_id %" PRIx32 "\n",
+	       ue->conn_id);
 	return NULL;
 }
 
diff --git a/openbsc/src/osmo-msc/msc_main.c b/openbsc/src/osmo-msc/msc_main.c
index 073836c..3d4ccd6 100644
--- a/openbsc/src/osmo-msc/msc_main.c
+++ b/openbsc/src/osmo-msc/msc_main.c
@@ -65,7 +65,6 @@
 #include <openbsc/osmo_bsc_rf.h>
 #include <openbsc/smpp.h>
 #include <osmocom/sigtran/sccp_sap.h>
-#include <osmocom/sigtran/sua.h>
 #include <openbsc/mgcpgw_client.h>
 
 #include <openbsc/msc_ifaces.h>
@@ -352,6 +351,8 @@
 	/* For --version, vty_init() must be called before handling options */
 	vty_init(&msc_vty_info);
 
+	osmo_ss7_init();
+
 	/* Parse options */
 	handle_options(argc, argv);
 
@@ -504,7 +505,7 @@
 	/* TODO: implement A-Interface and remove above legacy stuff. */
 
 	/* Set up IuCS */
-	iu_init(tall_msc_ctx, "127.0.0.1", 14001, rcvmsg_iu_cs, rx_iu_event);
+	iu_init(tall_msc_ctx, "OsmoMSC", 1, "127.0.0.3", "127.0.0.1", 0, rcvmsg_iu_cs, rx_iu_event);
 
 	if (msc_cmdline_config.daemonize) {
 		rc = osmo_daemonize();
diff --git a/openbsc/tests/msc_vlr/msc_vlr_test_umts_authen.err b/openbsc/tests/msc_vlr/msc_vlr_test_umts_authen.err
index eabc794..dcacbf9 100644
--- a/openbsc/tests/msc_vlr/msc_vlr_test_umts_authen.err
+++ b/openbsc/tests/msc_vlr/msc_vlr_test_umts_authen.err
@@ -518,10 +518,10 @@
   cipher_mode_cmd_sent == 1
   lu_result_sent == 0
 - MS sends SecurityModeControl acceptance, VLR accepts and sends GSUP LU Req to HLR
-DIUCS Looking for IuCS subscriber: link_id 0x23, conn_id 2a
-DIUCS   0: IMSI:901700000010650 Iu link 0x23, conn_id 42
+DIUCS Looking for IuCS subscriber: conn_id 2a
+DIUCS   0: IMSI:901700000010650 Iu conn_id 42
 DIUCS subscribers registered: 1
-DIUCS Found IuCS subscriber for link_id 0x23, conn_id 2a
+DIUCS Found IuCS subscriber for conn_id 2a
 DIUCS IuCS security mode complete for IMSI:901700000010650
 DMM <- SECURITY MODE COMPLETE IMSI:901700000010650
 DVLR vlr_lu_fsm(901700000010650){VLR_ULA_S_WAIT_CIPH}: Received Event VLR_ULA_E_CIPH_RES
@@ -701,10 +701,10 @@
   cipher_mode_cmd_sent == 1
   cm_service_result_sent == 0
 - MS sends SecurityModeControl acceptance, VLR accepts; above Ciphering is an implicit CM Service Accept
-DIUCS Looking for IuCS subscriber: link_id 0x23, conn_id 2a
-DIUCS   0: MSISDN:42342 Iu link 0x23, conn_id 42
+DIUCS Looking for IuCS subscriber: conn_id 2a
+DIUCS   0: MSISDN:42342 Iu conn_id 42
 DIUCS subscribers registered: 1
-DIUCS Found IuCS subscriber for link_id 0x23, conn_id 2a
+DIUCS Found IuCS subscriber for conn_id 2a
 DIUCS IuCS security mode complete for MSISDN:42342
 DMM <- SECURITY MODE COMPLETE MSISDN:42342
 DVLR Process_Access_Request_VLR(901700000010650){PR_ARQ_S_WAIT_CIPH}: Received Event PR_ARQ_E_CIPH_RES
@@ -837,10 +837,10 @@
   cipher_mode_cmd_sent == 1
   paging_stopped == 0
 - MS sends SecurityModeControl acceptance, VLR accepts and sends SMS
-DIUCS Looking for IuCS subscriber: link_id 0x23, conn_id 2a
-DIUCS   0: MSISDN:42342 Iu link 0x23, conn_id 42
+DIUCS Looking for IuCS subscriber: conn_id 2a
+DIUCS   0: MSISDN:42342 Iu conn_id 42
 DIUCS subscribers registered: 1
-DIUCS Found IuCS subscriber for link_id 0x23, conn_id 2a
+DIUCS Found IuCS subscriber for conn_id 2a
 DIUCS IuCS security mode complete for MSISDN:42342
 DMM <- SECURITY MODE COMPLETE MSISDN:42342
 DVLR Process_Access_Request_VLR(901700000010650){PR_ARQ_S_WAIT_CIPH}: Received Event PR_ARQ_E_CIPH_RES
@@ -1241,10 +1241,10 @@
   cipher_mode_cmd_sent == 1
   lu_result_sent == 0
 - MS sends SecurityModeControl acceptance, VLR accepts and sends GSUP LU Req to HLR
-DIUCS Looking for IuCS subscriber: link_id 0x23, conn_id 2a
-DIUCS   0: IMSI:901700000010650 Iu link 0x23, conn_id 42
+DIUCS Looking for IuCS subscriber: conn_id 2a
+DIUCS   0: IMSI:901700000010650 Iu conn_id 42
 DIUCS subscribers registered: 1
-DIUCS Found IuCS subscriber for link_id 0x23, conn_id 2a
+DIUCS Found IuCS subscriber for conn_id 2a
 DIUCS IuCS security mode complete for IMSI:901700000010650
 DMM <- SECURITY MODE COMPLETE IMSI:901700000010650
 DVLR vlr_lu_fsm(901700000010650){VLR_ULA_S_WAIT_CIPH}: Received Event VLR_ULA_E_CIPH_RES
diff --git a/openbsc/tests/msc_vlr/msc_vlr_tests.c b/openbsc/tests/msc_vlr/msc_vlr_tests.c
index d2ccb2a..e0de508 100644
--- a/openbsc/tests/msc_vlr/msc_vlr_tests.c
+++ b/openbsc/tests/msc_vlr/msc_vlr_tests.c
@@ -149,7 +149,6 @@
 	if (conn->via_ran == RAN_UTRAN_IU) {
 		struct ue_conn_ctx *ue_ctx = talloc_zero(conn, struct ue_conn_ctx);
 		*ue_ctx = (struct ue_conn_ctx){
-			.link = (void*)0x23,
 			.conn_id = 42,
 		};
 		conn->iu.ue_ctx = ue_ctx;