SUA: Port to new osmo_ss7 and SCCP code

If we use the infrastructure provided by osmo_ss7 on the lower layer and
the SCCP SCRC, SCLC and SCOC code on the upper side, not much of the
original sua.c code remains.  It looks much like the M3UA code now.

Change-Id: I193b74f58aa70c443ae17e78b5604246d6bc3f71

1 files changed, 191 insertions, 1190 deletions

diff --git a/src/sua.c b/src/sua.c
index 0f42d63..b0d5f8a 100644
--- a/src/sua.c
+++ b/src/sua.c
@@ -29,17 +29,20 @@
 #include <osmocom/core/logging.h>
 #include <osmocom/core/timer.h>
 #include <osmocom/core/socket.h>
+#include <osmocom/core/fsm.h>
 
 #include <osmocom/netif/stream.h>
 #include <osmocom/sigtran/xua_msg.h>
 
 #include <osmocom/sigtran/sccp_sap.h>
+#include <osmocom/sigtran/protocol/mtp.h>
 #include <osmocom/sigtran/protocol/sua.h>
-#include <osmocom/sigtran/sua.h>
+#include <osmocom/sigtran/protocol/m3ua.h>
+#include <osmocom/sigtran/osmo_ss7.h>
 
+#include "xua_asp_fsm.h"
 #include "xua_internal.h"
-
-#define SUA_MSGB_SIZE 1500
+#include "sccp_internal.h"
 
 /* Appendix C.4 of Q.714 (all in milliseconds) */
 #define CONNECTION_TIMER	( 1 * 60 * 100)
@@ -205,6 +208,7 @@ const struct xua_dialect xua_dialect_sua = {
 	.name = "SUA",
 	.ppid = SUA_PPID,
 	.port = SUA_PORT,
+	.log_subsys = DLSUA,
 	.class = {
 		[SUA_MSGC_MGMT] = &m3ua_msg_class_mgmt,
 		[SUA_MSGC_SNM] = &m3ua_msg_class_snm,
@@ -216,480 +220,81 @@ const struct xua_dialect xua_dialect_sua = {
 	},
 };
 
-
-static int DSUA = -1;
-
-struct osmo_sccp_user {
-	/* global list of SUA users? */
-	struct llist_head list;
-	/* set if we are a server */
-	struct osmo_stream_srv_link *server;
-	struct osmo_stream_cli *client;
-	struct llist_head links;
-	/* user call-back function in case of incoming primitives */
-	osmo_prim_cb prim_cb;
-	void *priv;
-};
-
-struct osmo_sccp_link {
-	/* list of SUA links per sua_user */
-	struct llist_head list;
-	/* sua user to which we belong */
-	struct osmo_sccp_user *user;
-	/* local list of (SCCP) connections in this link */
-	struct llist_head connections;
-	/* next connection local reference */
-	uint32_t next_id;
-	int is_server;
-	void *data;
-};
-
-enum sua_connection_state {
-	S_IDLE,
-	S_CONN_PEND_IN,
-	S_CONN_PEND_OUT,
-	S_ACTIVE,
-	S_DISCONN_PEND,
-	S_RESET_IN,
-	S_RESET_OUT,
-	S_BOTHWAY_RESET,
-	S_WAIT_CONN_CONF,
-};
-
-static const struct value_string conn_state_names[] = {
-	{ S_IDLE, 		"IDLE" },
-	{ S_CONN_PEND_IN,	"CONN_PEND_IN" },
-	{ S_CONN_PEND_OUT,	"CONN_PEND_OUT" },
-	{ S_ACTIVE,		"ACTIVE" },
-	{ S_DISCONN_PEND,	"DISCONN_PEND" },
-	{ S_RESET_IN,		"RESET_IN" },
-	{ S_RESET_OUT,		"RESET_OUT" },
-	{ S_BOTHWAY_RESET,	"BOTHWAY_RESET" },
-	{ S_WAIT_CONN_CONF,	"WAIT_CONN_CONF" },
-	{ 0, NULL }
-};
-
-struct sua_connection {
-	struct llist_head list;
-	struct osmo_sccp_link *link;
-	struct osmo_sccp_addr calling_addr;
-	struct osmo_sccp_addr called_addr;
-	uint32_t conn_id;
-	uint32_t remote_ref;
-	enum sua_connection_state state;
-	struct osmo_timer_list timer;
-	/* inactivity timers */
-	struct osmo_timer_list tias;
-	struct osmo_timer_list tiar;
-};
-
-
 /***********************************************************************
- * SUA Link and Connection handling
+ * ERROR generation
  ***********************************************************************/
 
-static struct osmo_sccp_link *sua_link_new(struct osmo_sccp_user *user, int is_server)
-{
-	struct osmo_sccp_link *link;
-
-	link = talloc_zero(user, struct osmo_sccp_link);
-	if (!link)
-		return NULL;
-
-	link->user = user;
-	link->is_server = is_server;
-	INIT_LLIST_HEAD(&link->connections);
-
-	llist_add_tail(&link->list, &user->links);
-
-	return link;
-}
-
-static void conn_destroy(struct sua_connection *conn);
-
-static void sua_link_destroy(struct osmo_sccp_link *link)
+static struct xua_msg *sua_gen_error(uint32_t err_code)
 {
-	struct sua_connection *conn;
-
-	llist_for_each_entry(conn, &link->connections, list)
-		conn_destroy(conn);
-
-	llist_del(&link->list);
-
-	/* FIXME: do we need to cleanup the sccp link? */
-
-	talloc_free(link);
-}
-
-static int sua_link_send(struct osmo_sccp_link *link, struct msgb *msg)
-{
-	msgb_sctp_ppid(msg) = SUA_PPID;
-
-	DEBUGP(DSUA, "sua_link_send(%s)\n", osmo_hexdump(msg->data, msgb_length(msg)));
-
-	if (link->is_server)
-		osmo_stream_srv_send(link->data, msg);
-	else
-		osmo_stream_cli_send(link->data, msg);
-
-	return 0;
-}
-
-static struct sua_connection *conn_find_by_id(struct osmo_sccp_link *link, uint32_t id)
-{
-	struct sua_connection *conn;
-
-	llist_for_each_entry(conn, &link->connections, list) {
-		if (conn->conn_id == id)
-			return conn;
-	}
-	return NULL;
-}
-
-static void tx_inact_tmr_cb(void *data)
-{
-	struct sua_connection *conn = data;
 	struct xua_msg *xua = xua_msg_alloc();
-	struct msgb *outmsg;
 
-	/* encode + send the CLDT */
-	xua->hdr = XUA_HDR(SUA_MSGC_CO, SUA_CO_COIT);
-	xua_msg_add_u32(xua, SUA_IEI_ROUTE_CTX, 0);	/* FIXME */
-	xua_msg_add_u32(xua, SUA_IEI_PROTO_CLASS, 2);
-	xua_msg_add_u32(xua, SUA_IEI_SRC_REF, conn->conn_id);
-	xua_msg_add_u32(xua, SUA_IEI_DEST_REF, conn->remote_ref);
-	/* optional: sequence number; credit (both class 3 only) */
-
-	outmsg = xua_to_msg(1, xua);
-	xua_msg_free(xua);
+	xua->hdr = XUA_HDR(SUA_MSGC_MGMT, SUA_MGMT_ERR);
+	xua->hdr.version = SUA_VERSION;
+	xua_msg_add_u32(xua, SUA_IEI_ERR_CODE, err_code);
 
-	sua_link_send(conn->link, outmsg);
+	return xua;
 }
 
-static void rx_inact_tmr_cb(void *data)
+static struct xua_msg *sua_gen_error_msg(uint32_t err_code, struct msgb *msg)
 {
-	struct sua_connection *conn = data;
+	struct xua_msg *xua = sua_gen_error(err_code);
+	unsigned int len_max_40 = msgb_length(msg);
 
-	/* FIXME: release connection */
-	/* Send N-DISCONNECT.ind to local user */
-	/* Send RLSD to peer */
-	/* enter disconnect pending state with release timer pending */
-}
-
-
-static struct sua_connection *conn_create_id(struct osmo_sccp_link *link, uint32_t conn_id)
-{
-	struct sua_connection *conn = talloc_zero(link, struct sua_connection);
-
-	conn->conn_id = conn_id;
-	conn->link = link;
-	conn->state = S_IDLE;
-
-	llist_add_tail(&conn->list, &link->connections);
-
-	conn->tias.cb = tx_inact_tmr_cb;
-	conn->tias.data = conn;
-	conn->tiar.cb = rx_inact_tmr_cb;
-	conn->tiar.data = conn;
-
-	return conn;
-}
-
-static struct sua_connection *conn_create(struct osmo_sccp_link *link)
-{
-	uint32_t conn_id;
-
-	do {
-		conn_id = link->next_id++;
-	} while (conn_find_by_id(link, conn_id));
-
-	return conn_create_id(link, conn_id);
-}
-
-static void conn_destroy(struct sua_connection *conn)
-{
-	/* FIXME: do some cleanup; inform user? */
-	osmo_timer_del(&conn->tias);
-	osmo_timer_del(&conn->tiar);
-	llist_del(&conn->list);
-	talloc_free(conn);
-}
-
-static void conn_state_set(struct sua_connection *conn,
-			   enum sua_connection_state state)
-{
-	DEBUGP(DSUA, "(%u) state chg %s->", conn->conn_id,
-		get_value_string(conn_state_names, conn->state));
-	DEBUGPC(DSUA, "%s\n",
-		get_value_string(conn_state_names, state));
-	conn->state = state;
-}
-
-static void conn_restart_tx_inact_timer(struct sua_connection *conn)
-{
-	osmo_timer_schedule(&conn->tias, TX_INACT_TIMER / 100,
-			    (TX_INACT_TIMER % 100) * 10);
-}
+	if (len_max_40 > 40)
+		len_max_40 = 40;
 
-static void conn_restart_rx_inact_timer(struct sua_connection *conn)
-{
-	osmo_timer_schedule(&conn->tiar, RX_INACT_TIMER / 100,
-			    (RX_INACT_TIMER % 100) * 10);
-}
+	xua_msg_add_data(xua, SUA_IEI_DIAG_INFO, len_max_40, msgb_data(msg));
 
-static void conn_start_inact_timers(struct sua_connection *conn)
-{
-	conn_restart_tx_inact_timer(conn);
-	conn_restart_rx_inact_timer(conn);
+	return xua;
 }
 
 /***********************************************************************
- * Handling of messages from the User SAP
+ * Transmitting SUA messsages to SCTP
  ***********************************************************************/
 
-/* user program sends us a N-CONNNECT.req to initiate a new connection */
-static int sua_connect_req(struct osmo_sccp_link *link, struct osmo_scu_prim *prim)
+static int sua_tx_xua_asp(struct osmo_ss7_asp *asp, struct xua_msg *xua)
 {
-	struct osmo_scu_connect_param *par = &prim->u.connect;
-	struct xua_msg *xua = xua_msg_alloc();
-	struct sua_connection *conn;
-	struct msgb *outmsg;
+	struct msgb *msg = xua_to_msg(SUA_VERSION, xua);
 
-	if (par->sccp_class != 2) {
-		LOGP(DSUA, LOGL_ERROR, "N-CONNECT.req for unsupported "
-			"SCCP class %u\n", par->sccp_class);
-		/* FIXME: Send primitive to user */
-		return -EINVAL;
-	}
+	OSMO_ASSERT(asp->cfg.proto == OSMO_SS7_ASP_PROT_SUA);
 
-	conn = conn_create_id(link, par->conn_id);
-	if (!conn) {
-		/* FIXME: Send primitive to user */
-		return -EINVAL;
-	}
-
-	memcpy(&conn->called_addr, &par->called_addr,
-		sizeof(conn->called_addr));
-	memcpy(&conn->calling_addr, &par->calling_addr,
-		sizeof(conn->calling_addr));
-
-	/* encode + send the CLDT */
-	xua->hdr = XUA_HDR(SUA_MSGC_CO, SUA_CO_CORE);
-	xua_msg_add_u32(xua, SUA_IEI_ROUTE_CTX, 0);	/* FIXME */
-	xua_msg_add_u32(xua, SUA_IEI_PROTO_CLASS, par->sccp_class);
-	xua_msg_add_u32(xua, SUA_IEI_SRC_REF, conn->conn_id);
-	xua_msg_add_sccp_addr(xua, SUA_IEI_DEST_ADDR, &par->called_addr);
-	xua_msg_add_u32(xua, SUA_IEI_SEQ_CTRL, 0); /* FIXME */
-	/* sequence number */
-	if (par->calling_addr.presence)
-		xua_msg_add_sccp_addr(xua, SUA_IEI_SRC_ADDR, &par->calling_addr);
-	/* optional: hop count; importance; priority; credit */
-	if (msgb_l2(prim->oph.msg))
-		xua_msg_add_data(xua, SUA_IEI_DATA, msgb_l2len(prim->oph.msg),
-				 msgb_l2(prim->oph.msg));
-
-	outmsg = xua_to_msg(1, xua);
 	xua_msg_free(xua);
 
-	/* FIXME: Start CONNECTION_TIMER */
-	conn_state_set(conn, S_CONN_PEND_OUT);
-
-	return sua_link_send(link, outmsg);
-}
-
-/* user program sends us a N-CONNNECT.resp, presumably against a
- * N-CONNECT.ind */
-static int sua_connect_resp(struct osmo_sccp_link *link, struct osmo_scu_prim *prim)
-{
-	struct osmo_scu_connect_param *par = &prim->u.connect;
-	struct xua_msg *xua = xua_msg_alloc();
-	struct sua_connection *conn;
-	struct msgb *outmsg;
-
-	/* check if we already know a connection for this conn_id */
-	conn = conn_find_by_id(link, par->conn_id);
-	if (!conn) {
-		LOGP(DSUA, LOGL_ERROR, "N-CONNECT.resp for unknown "
-			"connection ID %u\n", par->conn_id);
-		/* FIXME: Send primitive to user */
-		return -ENODEV;
-	}
-
-	if (conn->state != S_CONN_PEND_IN) {
-		LOGP(DSUA, LOGL_ERROR, "N-CONNECT.resp in wrong state %s\n",
-			get_value_string(conn_state_names, conn->state));
-		/* FIXME: Send primitive to user */
-		return -EINVAL;
+	if (!msg) {
+		LOGPASP(asp, DLSUA, LOGL_ERROR, "Error encoding SUA Msg\n");
+		return -1;
 	}
 
-	/* encode + send the COAK message */
-	xua = xua_msg_alloc();
-	xua->hdr = XUA_HDR(SUA_MSGC_CO, SUA_CO_COAK);
-	xua_msg_add_u32(xua, SUA_IEI_ROUTE_CTX, 0);	/* FIXME */
-	xua_msg_add_u32(xua, SUA_IEI_PROTO_CLASS, par->sccp_class);
-	xua_msg_add_u32(xua, SUA_IEI_DEST_REF, conn->remote_ref);
-	xua_msg_add_u32(xua, SUA_IEI_SRC_REF, conn->conn_id);
-	xua_msg_add_u32(xua, SUA_IEI_SEQ_CTRL, 0);	/* FIXME */
-	/* sequence number */
-	if (par->calling_addr.presence)
-		xua_msg_add_sccp_addr(xua, SUA_IEI_SRC_ADDR, &par->calling_addr);
-	/* optional: hop count; importance; priority */
-	/* FIXME: destination address will be present in case the CORE
-	 * message conveys the source address parameter */
-	if (par->called_addr.presence)
-		xua_msg_add_sccp_addr(xua, SUA_IEI_DEST_ADDR, &par->called_addr);
-	if (msgb_l2(prim->oph.msg))
-		xua_msg_add_data(xua, SUA_IEI_DATA, msgb_l2len(prim->oph.msg),
-				 msgb_l2(prim->oph.msg));
-
-	outmsg = xua_to_msg(1, xua);
-	xua_msg_free(xua);
-
-	conn_state_set(conn, S_ACTIVE);
-	conn_start_inact_timers(conn);
-
-	return sua_link_send(link, outmsg);
+	msgb_sctp_ppid(msg) = SUA_PPID;
+	return osmo_ss7_asp_send(asp, msg);
 }
 
-/* user wants to send connection-oriented data */
-static int sua_data_req(struct osmo_sccp_link *link, struct osmo_scu_prim *prim)
+/*! \brief Send a given xUA message via a given SUA Application Server
+ *  \param[in] as Application Server through which to send \ref xua
+ *  \param[in] xua xUA message to be sent
+ *  \return 0 on success; negative on error */
+int sua_tx_xua_as(struct osmo_ss7_as *as, struct xua_msg *xua)
 {
-	struct osmo_scu_data_param *par = &prim->u.data;
-	struct xua_msg *xua;
-	struct sua_connection *conn;
-	struct msgb *outmsg;
-
-	/* check if we know about this conncetion, and obtain reference */
-	conn = conn_find_by_id(link, par->conn_id);
-	if (!conn) {
-		LOGP(DSUA, LOGL_ERROR, "N-DATA.req for unknown "
-			"connection ID %u\n", par->conn_id);
-		/* FIXME: Send primitive to user */
-		return -ENODEV;
-	}
-
-	if (conn->state != S_ACTIVE) {
-		LOGP(DSUA, LOGL_ERROR, "N-DATA.req in wrong state %s\n",
-			get_value_string(conn_state_names, conn->state));
-		/* FIXME: Send primitive to user */
-		return -EINVAL;
-	}
-
-	conn_restart_tx_inact_timer(conn);
-
-	/* encode + send the CODT message */
-	xua = xua_msg_alloc();
-	xua->hdr = XUA_HDR(SUA_MSGC_CO, SUA_CO_CODT);
-	xua_msg_add_u32(xua, SUA_IEI_ROUTE_CTX, 0);	/* FIXME */
-	/* Sequence number only in expedited data */
-	xua_msg_add_u32(xua, SUA_IEI_DEST_REF, conn->remote_ref);
-	/* optional: priority; correlation id */
-	xua_msg_add_data(xua, SUA_IEI_DATA, msgb_l2len(prim->oph.msg),
-			 msgb_l2(prim->oph.msg));
+	struct osmo_ss7_asp *asp;
+	unsigned int i;
 
-	outmsg = xua_to_msg(1, xua);
-	xua_msg_free(xua);
+	OSMO_ASSERT(as->cfg.proto == OSMO_SS7_ASP_PROT_SUA);
 
-	return sua_link_send(link, outmsg);
-}
-
-/* user wants to disconnect a connection */
-static int sua_disconnect_req(struct osmo_sccp_link *link, struct osmo_scu_prim *prim)
-{
-	struct osmo_scu_disconn_param *par = &prim->u.disconnect;
-	struct xua_msg *xua;
-	struct sua_connection *conn;
-	struct msgb *outmsg;
-
-	/* resolve reference of connection */
-	conn = conn_find_by_id(link, par->conn_id);
-	if (!conn) {
-		LOGP(DSUA, LOGL_ERROR, "N-DISCONNECT.req for unknown "
-			"connection ID %u\n", par->conn_id);
-		/* FIXME: Send primitive to user */
-		return -ENODEV;
+	/* FIXME: Select ASP within AS depending on traffic mode */
+	for (i = 0; i < ARRAY_SIZE(as->cfg.asps); i++) {
+		asp = as->cfg.asps[i];
+		if (!asp)
+			continue;
+		if (asp)
+			break;
 	}
-
-	/* encode + send the RELRE */
-	xua = xua_msg_alloc();
-	xua->hdr = XUA_HDR(SUA_MSGC_CO, SUA_CO_RELRE);
-	xua_msg_add_u32(xua, SUA_IEI_ROUTE_CTX, 0);	/* FIXME */
-	xua_msg_add_u32(xua, SUA_IEI_DEST_REF, conn->remote_ref);
-	xua_msg_add_u32(xua, SUA_IEI_SRC_REF, conn->conn_id);
-	xua_msg_add_u32(xua, SUA_IEI_CAUSE, par->cause);
-	/* optional: importance */
-	if (msgb_l2(prim->oph.msg))
-		xua_msg_add_data(xua, SUA_IEI_DATA, msgb_l2len(prim->oph.msg),
-				 msgb_l2(prim->oph.msg));
-
-	outmsg = xua_to_msg(1, xua);
-	xua_msg_free(xua);
-
-	conn_state_set(conn, S_DISCONN_PEND);
-	conn_destroy(conn);
-
-	LOGP(DSUA, LOGL_NOTICE, "About to send the SUA RELRE\n");
-	return sua_link_send(link, outmsg);
-}
-
-/* user wants to send connectionless data */
-static int sua_unitdata_req(struct osmo_sccp_link *link, struct osmo_scu_prim *prim)
-{
-	struct osmo_scu_unitdata_param *par = &prim->u.unitdata;
-	struct xua_msg *xua = xua_msg_alloc();
-	struct msgb *outmsg;
-
-	/* encode + send the CLDT */
-	xua->hdr = XUA_HDR(SUA_MSGC_CL, SUA_CL_CLDT);
-	xua_msg_add_u32(xua, SUA_IEI_ROUTE_CTX, 0);	/* FIXME */
-	xua_msg_add_u32(xua, SUA_IEI_PROTO_CLASS, 0);
-	xua_msg_add_sccp_addr(xua, SUA_IEI_SRC_ADDR, &par->calling_addr);
-	xua_msg_add_sccp_addr(xua, SUA_IEI_DEST_ADDR, &par->called_addr);
-	xua_msg_add_u32(xua, SUA_IEI_SEQ_CTRL, par->in_sequence_control);
-	/* optional: importance, ... correlation id? */
-	xua_msg_add_data(xua, SUA_IEI_DATA, msgb_l2len(prim->oph.msg),
-			 msgb_l2(prim->oph.msg));
-
-	outmsg = xua_to_msg(1, xua);
-	xua_msg_free(xua);
-
-	return sua_link_send(link, outmsg);
-}
-
-/* user hands us a SCCP-USER SAP primitive down into the stack */
-int osmo_sua_user_link_down(struct osmo_sccp_link *link, struct osmo_prim_hdr *oph)
-{
-	struct osmo_scu_prim *prim = (struct osmo_scu_prim *) oph;
-	struct msgb *msg = prim->oph.msg;
-	int rc = 0;
-
-	LOGP(DSUA, LOGL_DEBUG, "Received SCCP User Primitive (%s)\n",
-		osmo_scu_prim_name(&prim->oph));
-
-	switch (OSMO_PRIM_HDR(&prim->oph)) {
-	case OSMO_PRIM(OSMO_SCU_PRIM_N_CONNECT, PRIM_OP_REQUEST):
-		rc = sua_connect_req(link, prim);
-		break;
-	case OSMO_PRIM(OSMO_SCU_PRIM_N_CONNECT, PRIM_OP_RESPONSE):
-		rc = sua_connect_resp(link, prim);
-		break;
-	case OSMO_PRIM(OSMO_SCU_PRIM_N_DATA, PRIM_OP_REQUEST):
-		rc = sua_data_req(link, prim);
-		break;
-	case OSMO_PRIM(OSMO_SCU_PRIM_N_DISCONNECT, PRIM_OP_REQUEST):
-		rc = sua_disconnect_req(link, prim);
-		break;
-	case OSMO_PRIM(OSMO_SCU_PRIM_N_UNITDATA, PRIM_OP_REQUEST):
-		rc = sua_unitdata_req(link, prim);
-		break;
-	default:
-		rc = -1;
+	if (!asp) {
+		LOGP(DLSUA, LOGL_ERROR, "No ASP in AS, dropping message\n");
+		xua_msg_free(xua);
+		return -ENODEV;
 	}
 
-	if (rc != 1)
-		msgb_free(msg);
-
-	return rc;
+	return sua_tx_xua_asp(asp, xua);
 }
 
 /***********************************************************************
@@ -750,12 +355,12 @@ int sua_addr_parse_part(struct osmo_sccp_addr *out,
 
 	memset(out, 0, sizeof(*out));
 
-	LOGP(DSUA, LOGL_DEBUG, "%s(IEI=0x%04x) (%d) %s\n", __func__,
+	LOGP(DLSUA, LOGL_DEBUG, "%s(IEI=0x%04x) (%d) %s\n", __func__,
 	     param->tag, param->len,
 	     osmo_hexdump(param->dat, param->len));
 
 	if (param->len < 4) {
-		LOGP(DSUA, LOGL_ERROR, "SUA IEI 0x%04x: invalid address length: %d\n",
+		LOGP(DLSUA, LOGL_ERROR, "SUA IEI 0x%04x: invalid address length: %d\n",
 		     param->tag, param->len);
 		return -EINVAL;
 	}
@@ -778,14 +383,14 @@ int sua_addr_parse_part(struct osmo_sccp_addr *out,
 		break;
 	case SUA_RI_HOST:
 	default:
-		LOGP(DSUA, LOGL_ERROR, "SUA IEI 0x%04x: Routing Indicator not supported yet: %d\n",
+		LOGP(DLSUA, LOGL_ERROR, "SUA IEI 0x%04x: Routing Indicator not supported yet: %d\n",
 		     param->tag, ri);
 		return -ENOTSUP;
 	}
 
 	if (ai != 7) {
 #if 0
-		LOGP(DSUA, LOGL_ERROR, "SUA IEI 0x%04x: Address Indicator not supported yet: %x\n",
+		LOGP(DLSUA, LOGL_ERROR, "SUA IEI 0x%04x: Address Indicator not supported yet: %x\n",
 		     param->tag, ai);
 		return -ENOTSUP;
 #endif
@@ -805,7 +410,7 @@ int sua_addr_parse_part(struct osmo_sccp_addr *out,
 		par_len = ntohs(par->len);
 		par_datalen = par_len - sizeof(*par);
 
-		LOGP(DSUA, LOGL_DEBUG, "SUA IEI 0x%04x pos %hu/%hu: subpart tag 0x%04x, len %hu\n",
+		LOGP(DLSUA, LOGL_DEBUG, "SUA IEI 0x%04x pos %hu/%hu: subpart tag 0x%04x, len %hu\n",
 		     param->tag, pos, param->len, par_tag, par_len);
 
 		switch (par_tag) {
@@ -838,7 +443,7 @@ int sua_addr_parse_part(struct osmo_sccp_addr *out,
 			out->presence |= OSMO_SCCP_ADDR_T_IPv4;
 			break;
 		default:
-			LOGP(DSUA, LOGL_ERROR, "SUA IEI 0x%04x: Unknown subpart tag %hd\n",
+			LOGP(DLSUA, LOGL_ERROR, "SUA IEI 0x%04x: Unknown subpart tag %hd\n",
 			     param->tag, par_tag);
 			goto subpar_fail;
 		}
@@ -849,7 +454,7 @@ int sua_addr_parse_part(struct osmo_sccp_addr *out,
 	return 0;
 
 subpar_fail:
-	LOGP(DSUA, LOGL_ERROR, "Failed to parse subparts of address IEI=0x%04x\n",
+	LOGP(DLSUA, LOGL_ERROR, "Failed to parse subparts of address IEI=0x%04x\n",
 	     param->tag);
 	return -EINVAL;
 }
@@ -870,809 +475,205 @@ int sua_addr_parse(struct osmo_sccp_addr *out, struct xua_msg *xua, uint16_t iei
 	return sua_addr_parse_part(out, param);
 }
 
-static int sua_rx_cldt(struct osmo_sccp_link *link, struct xua_msg *xua)
+/* connectionless messages received from socket */
+static int sua_rx_cl(struct osmo_ss7_asp *asp, struct xua_msg *xua)
 {
-	struct osmo_scu_prim *prim;
-	struct osmo_scu_unitdata_param *param;
-	struct xua_msg_part *data_ie = xua_msg_find_tag(xua, SUA_IEI_DATA);
-	struct msgb *upmsg = sccp_msgb_alloc(__func__);
-	uint32_t protocol_class;
-
-	/* fill primitive */
-	prim = (struct osmo_scu_prim *) msgb_put(upmsg, sizeof(*prim));
-	param = &prim->u.unitdata;
-	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
-			OSMO_SCU_PRIM_N_UNITDATA,
-			PRIM_OP_INDICATION, upmsg);
-	sua_addr_parse(&param->called_addr, xua, SUA_IEI_DEST_ADDR);
-	sua_addr_parse(&param->calling_addr, xua, SUA_IEI_SRC_ADDR);
-	param->in_sequence_control = xua_msg_get_u32(xua, SUA_IEI_SEQ_CTRL);
-	protocol_class = xua_msg_get_u32(xua, SUA_IEI_PROTO_CLASS);
-	param->return_option = protocol_class & 0x80;
-	param->importance = xua_msg_get_u32(xua, SUA_IEI_IMPORTANCE);
-
-	/* copy data */
-	upmsg->l2h = msgb_put(upmsg, data_ie->len);
-	memcpy(upmsg->l2h, data_ie->dat, data_ie->len);
-
-	/* send to user SAP */
-	link->user->prim_cb(&prim->oph, link);
+	struct osmo_sccp_instance *inst = asp->inst->sccp;
 
-	return 0;
+	/* We feed into SCRC, which then hands the message into
+	 * either SCLC or SCOC, or forwards it to MTP */
+	return scrc_rx_mtp_xfer_ind_xua(inst, xua);
 }
 
-
-/* connectioness messages received from socket */
-static int sua_rx_cl(struct osmo_sccp_link *link,
-		     struct xua_msg *xua, struct msgb *msg)
+/* connection-oriented messages received from socket */
+static int sua_rx_co(struct osmo_ss7_asp *asp, struct xua_msg *xua)
 {
-	int rc = -1;
+	struct osmo_sccp_instance *inst = asp->inst->sccp;
 
-	switch (xua->hdr.msg_type) {
-	case SUA_CL_CLDT:
-		rc = sua_rx_cldt(link, xua);
-		break;
-	case SUA_CL_CLDR:
-	default:
-		break;
-	}
-
-	return rc;
+	/* We feed into SCRC, which then hands the message into
+	 * either SCLC or SCOC, or forwards it to MTP */
+	return scrc_rx_mtp_xfer_ind_xua(inst, xua);
 }
 
-/* RFC 3868 3.3.3 / SCCP CR (Connection Request) */
-static int sua_rx_core(struct osmo_sccp_link *link, struct xua_msg *xua)
+static int sua_rx_mgmt_err(struct osmo_ss7_asp *asp, struct xua_msg *xua)
 {
-	struct osmo_scu_prim *prim;
-	struct osmo_scu_connect_param *param;
-	struct xua_msg_part *data_ie = xua_msg_find_tag(xua, SUA_IEI_DATA);
-	struct msgb *upmsg;
-	struct sua_connection *conn;
-
-	/* fill conn */
-	conn = conn_create(link);
-	sua_addr_parse(&conn->called_addr, xua, SUA_IEI_DEST_ADDR);
-	sua_addr_parse(&conn->calling_addr, xua, SUA_IEI_SRC_ADDR);
-	conn->remote_ref = xua_msg_get_u32(xua, SUA_IEI_SRC_REF);
-
-	/* fill primitive */
-	upmsg = sccp_msgb_alloc(__func__);
-	prim = (struct osmo_scu_prim *) msgb_put(upmsg, sizeof(*prim));
-	param = &prim->u.connect;
-	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
-			OSMO_SCU_PRIM_N_CONNECT,
-			PRIM_OP_INDICATION, upmsg);
-	param->conn_id = conn->conn_id;
-	memcpy(&param->called_addr, &conn->called_addr,
-		sizeof(param->called_addr));
-	memcpy(&param->calling_addr, &conn->calling_addr,
-		sizeof(param->calling_addr));
-	//param->in_sequence_control;
-	param->sccp_class = xua_msg_get_u32(xua, SUA_IEI_PROTO_CLASS) & 3;
-	param->importance = xua_msg_get_u32(xua, SUA_IEI_IMPORTANCE);
-
-	if (data_ie) {
-		/* copy data */
-		upmsg->l2h = msgb_put(upmsg, data_ie->len);
-		memcpy(upmsg->l2h, data_ie->dat, data_ie->len);
-	}
-
-	conn_state_set(conn, S_CONN_PEND_IN);
+	uint32_t err_code = xua_msg_get_u32(xua, SUA_IEI_ERR_CODE);
 
-	/* send to user SAP */
-	link->user->prim_cb(&prim->oph, link);
+	LOGPASP(asp, DLSUA, LOGL_ERROR, "Received MGMT_ERR '%s': %s\n",
+		get_value_string(m3ua_err_names, err_code),
+		xua_msg_dump(xua, &xua_dialect_sua));
 
+	/* NEVER return != 0 here, as we cannot respont to an ERR
+	 * message with another ERR! */
 	return 0;
 }
 
-/* RFC 3868 3.3.4 / SCCP CC (Connection Confirm) */
-static int sua_rx_coak(struct osmo_sccp_link *link, struct xua_msg *xua)
+static int sua_rx_mgmt_ntfy(struct osmo_ss7_asp *asp, struct xua_msg *xua)
 {
-	struct osmo_scu_prim *prim;
-	struct sua_connection *conn;
-	struct osmo_scu_connect_param *param;
-	struct xua_msg_part *data_ie = xua_msg_find_tag(xua, SUA_IEI_DATA);
-	struct msgb *upmsg;
-	uint32_t conn_id = xua_msg_get_u32(xua, SUA_IEI_DEST_REF);
-
-	/* resolve conn */
-	conn = conn_find_by_id(link, conn_id);
-	if (!conn) {
-		LOGP(DSUA, LOGL_ERROR, "COAK for unknown reference %u\n",
-			conn_id);
-		/* FIXME: send error reply down the sua link? */
-		return -1;
-	}
-	conn_restart_rx_inact_timer(conn);
-
-	if (conn->state != S_CONN_PEND_OUT) {
-		LOGP(DSUA, LOGL_ERROR, "COAK in wrong state %s\n",
-			get_value_string(conn_state_names, conn->state));
-		/* FIXME: send error reply down the sua link? */
-		return -EINVAL;
-	}
-
-	/* track remote reference */
-	conn->remote_ref = xua_msg_get_u32(xua, SUA_IEI_SRC_REF);
-
-	/* fill primitive */
-	upmsg = sccp_msgb_alloc(__func__);
-	prim = (struct osmo_scu_prim *) msgb_put(upmsg, sizeof(*prim));
-	param = &prim->u.connect;
-	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
-			OSMO_SCU_PRIM_N_CONNECT,
-			PRIM_OP_CONFIRM, upmsg);
-	param->conn_id = conn->conn_id;
-	memcpy(&param->called_addr, &conn->called_addr,
-		sizeof(param->called_addr));
-	memcpy(&param->calling_addr, &conn->calling_addr,
-		sizeof(param->calling_addr));
-	//param->in_sequence_control;
-	param->sccp_class = xua_msg_get_u32(xua, SUA_IEI_PROTO_CLASS) & 3;
-	param->importance = xua_msg_get_u32(xua, SUA_IEI_IMPORTANCE);
-
-	if (data_ie) {
-		/* copy data */
-		upmsg->l2h = msgb_put(upmsg, data_ie->len);
-		memcpy(upmsg->l2h, data_ie->dat, data_ie->len);
-	}
+	struct m3ua_notify_params ntfy;
+	const char *type_name, *info_name;
 
-	conn_state_set(conn, S_ACTIVE);
-	conn_start_inact_timers(conn);
+	m3ua_decode_notify(&ntfy, asp, xua);
 
-	/* send to user SAP */
-	link->user->prim_cb(&prim->oph, link);
+	type_name = get_value_string(m3ua_ntfy_type_names, ntfy.status_type);
 
-	return 0;
-}
-
-/* RFC 3868 3.3.5 / SCCP CREF (Connection Refused) */
-static int sua_rx_coref(struct osmo_sccp_link *link, struct xua_msg *xua)
-{
-	struct osmo_scu_prim *prim;
-	struct sua_connection *conn;
-	struct osmo_scu_disconn_param *param;
-	struct xua_msg_part *data_ie = xua_msg_find_tag(xua, SUA_IEI_DATA);
-	struct msgb *upmsg;
-	uint32_t conn_id = xua_msg_get_u32(xua, SUA_IEI_DEST_REF);
-	uint32_t cause;
-
-	/* resolve conn */
-	conn = conn_find_by_id(link, conn_id);
-	if (!conn) {
-		LOGP(DSUA, LOGL_ERROR, "COREF for unknown reference %u\n",
-			conn_id);
-		/* FIXME: send error reply down the sua link? */
-		return -1;
-	}
-	conn_restart_rx_inact_timer(conn);
-
-	/* fill primitive */
-	upmsg = sccp_msgb_alloc(__func__);
-	prim = (struct osmo_scu_prim *) msgb_put(upmsg, sizeof(*prim));
-	param = &prim->u.disconnect;
-	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
-			OSMO_SCU_PRIM_N_DISCONNECT,
-			PRIM_OP_INDICATION, upmsg);
-	param->conn_id = conn_id;
-	param->responding_addr = conn->called_addr;
-	param->originator = OSMO_SCCP_ORIG_UNDEFINED;
-	//param->in_sequence_control;
-	/* TODO evaluate cause:
-	 * cause = xua_msg_get_u32(xua, SUA_IEI_CAUSE); */
-	/* optional: src addr */
-	/* optional: dest addr */
-	param->importance = xua_msg_get_u32(xua, SUA_IEI_IMPORTANCE);
-	if (data_ie) {
-		/* copy data */
-		upmsg->l2h = msgb_put(upmsg, data_ie->len);
-		memcpy(upmsg->l2h, data_ie->dat, data_ie->len);
+	switch (ntfy.status_type) {
+	case M3UA_NOTIFY_T_STATCHG:
+		info_name = get_value_string(m3ua_ntfy_stchg_names,
+						ntfy.status_info);
+		break;
+	case M3UA_NOTIFY_T_OTHER:
+		info_name = get_value_string(m3ua_ntfy_other_names,
+						ntfy.status_info);
+		break;
+	default:
+		info_name = "NULL";
+		break;
 	}
+	LOGPASP(asp, DLSUA, LOGL_NOTICE, "Received NOTIFY Type %s:%s (%s)\n",
+		type_name, info_name,
+		ntfy.info_string ? ntfy.info_string : "");
 
-	/* send to user SAP */
-	link->user->prim_cb(&prim->oph, link);
-
-	conn_state_set(conn, S_IDLE);
-	conn_destroy(conn);
+	if (ntfy.info_string)
+		talloc_free(ntfy.info_string);
 
+	/* TODO: should we report this soemwhere? */
 	return 0;
 }
 
-/* RFC 3868 3.3.6 / SCCP RLSD (Released) */
-static int sua_rx_relre(struct osmo_sccp_link *link, struct xua_msg *xua)
+static int sua_rx_mgmt(struct osmo_ss7_asp *asp, struct xua_msg *xua)
 {
-	struct osmo_scu_prim *prim;
-	struct sua_connection *conn;
-	struct osmo_scu_disconn_param *param;
-	struct xua_msg_part *data_ie = xua_msg_find_tag(xua, SUA_IEI_DATA);
-	struct msgb *upmsg;
-	uint32_t conn_id = xua_msg_get_u32(xua, SUA_IEI_DEST_REF);
-	uint32_t cause;
-
-	/* resolve conn */
-	conn = conn_find_by_id(link, conn_id);
-	if (!conn) {
-		LOGP(DSUA, LOGL_ERROR, "RELRE for unknown reference %u\n",
-			conn_id);
-		/* FIXME: send error reply down the sua link? */
-		return -1;
-	}
-
-	/* fill primitive */
-	upmsg = sccp_msgb_alloc(__func__);
-	prim = (struct osmo_scu_prim *) msgb_put(upmsg, sizeof(*prim));
-	param = &prim->u.disconnect;
-	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
-			OSMO_SCU_PRIM_N_DISCONNECT,
-			PRIM_OP_INDICATION, upmsg); /* what primitive? */
-
-	param->conn_id = conn_id;
-	/* source reference */
-	cause = xua_msg_get_u32(xua, SUA_IEI_CAUSE);
-	param->importance = xua_msg_get_u32(xua, SUA_IEI_IMPORTANCE);
-	if (data_ie) {
-		/* copy data */
-		upmsg->l2h = msgb_put(upmsg, data_ie->len);
-		memcpy(upmsg->l2h, data_ie->dat, data_ie->len);
-	}
-
-	param->responding_addr = conn->called_addr;
-	param->originator = OSMO_SCCP_ORIG_UNDEFINED;
-
-	/* send to user SAP */
-	link->user->prim_cb(&prim->oph, link);
-
-	conn_state_set(conn, S_IDLE);
-	conn_destroy(conn);
-
-	return 0;
-}
+	switch (xua->hdr.msg_type) {
+	case SUA_MGMT_ERR:
+		return sua_rx_mgmt_err(asp, xua);
+	case SUA_MGMT_NTFY:
+		return sua_rx_mgmt_ntfy(asp, xua);
+	default:
+		return SUA_ERR_UNSUPP_MSG_TYPE;
+	}
+}
+
+/* map from SUA ASPSM/ASPTM to xua_asp_fsm event */
+static const struct xua_msg_event_map sua_aspxm_map[] = {
+	{ SUA_MSGC_ASPSM, SUA_ASPSM_UP, XUA_ASP_E_ASPSM_ASPUP },
+	{ SUA_MSGC_ASPSM, SUA_ASPSM_DOWN, XUA_ASP_E_ASPSM_ASPDN },
+	{ SUA_MSGC_ASPSM, SUA_ASPSM_BEAT, XUA_ASP_E_ASPSM_BEAT },
+	{ SUA_MSGC_ASPSM, SUA_ASPSM_UP_ACK, XUA_ASP_E_ASPSM_ASPUP_ACK },
+	{ SUA_MSGC_ASPSM, SUA_ASPSM_DOWN_ACK, XUA_ASP_E_ASPSM_ASPDN_ACK },
+	{ SUA_MSGC_ASPSM, SUA_ASPSM_BEAT_ACK, XUA_ASP_E_ASPSM_BEAT_ACK },
+	{ SUA_MSGC_ASPTM, SUA_ASPTM_ACTIVE, XUA_ASP_E_ASPTM_ASPAC },
+	{ SUA_MSGC_ASPTM, SUA_ASPTM_INACTIVE, XUA_ASP_E_ASPTM_ASPIA },
+	{ SUA_MSGC_ASPTM, SUA_ASPTM_ACTIVE_ACK, XUA_ASP_E_ASPTM_ASPAC_ACK },
+	{ SUA_MSGC_ASPTM, SUA_ASPTM_INACTIVE_ACK, XUA_ASP_E_ASPTM_ASPIA_ACK },
+};
 
-/* RFC 3868 3.3.7 / SCCP RLC (Release Complete)*/
-static int sua_rx_relco(struct osmo_sccp_link *link, struct xua_msg *xua)
+static int sua_rx_asp(struct osmo_ss7_asp *asp, struct xua_msg *xua)
 {
-	struct osmo_scu_prim *prim;
-	struct sua_connection *conn;
-	struct osmo_scu_disconn_param *param;
-	struct msgb *upmsg;
-	uint32_t conn_id = xua_msg_get_u32(xua, SUA_IEI_DEST_REF);
-
-	/* resolve conn */
-	conn = conn_find_by_id(link, conn_id);
-	if (!conn) {
-		LOGP(DSUA, LOGL_ERROR, "RELCO for unknown reference %u\n",
-			conn_id);
-		/* FIXME: send error reply down the sua link? */
-		return -1;
-	}
-	conn_restart_rx_inact_timer(conn);
-
-	/* fill primitive */
-	upmsg = sccp_msgb_alloc(__func__);
-	prim = (struct osmo_scu_prim *) msgb_put(upmsg, sizeof(*prim));
-	param = &prim->u.disconnect;
-	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
-			OSMO_SCU_PRIM_N_DISCONNECT,
-			PRIM_OP_CONFIRM, upmsg); /* what primitive? */
-
-	param->conn_id = conn_id;
-	/* source reference */
-	param->importance = xua_msg_get_u32(xua, SUA_IEI_IMPORTANCE);
-
-	param->responding_addr = conn->called_addr;
-	param->originator = OSMO_SCCP_ORIG_UNDEFINED;
+	int event;
 
-	/* send to user SAP */
-	link->user->prim_cb(&prim->oph, link);
+	/* map from the SUA message class and message type to the XUA
+	 * ASP FSM event number */
+	event = xua_msg_event_map(xua, sua_aspxm_map,
+				      ARRAY_SIZE(sua_aspxm_map));
+	if (event < 0)
+		return SUA_ERR_UNSUPP_MSG_TYPE;
 
-	conn_destroy(conn);
+	/* deliver that event to the ASP FSM */
+	osmo_fsm_inst_dispatch(asp->fi, event, xua);
 
 	return 0;
-
 }
 
-/* RFC3868 3.3.1 / SCCP DT1 (Data Form 1) */
-static int sua_rx_codt(struct osmo_sccp_link *link, struct xua_msg *xua)
+/*! \brief process SUA message received from socket
+ *  \param[in] asp Application Server Process receiving \ref msg
+ *  \param[in] msg received message buffer
+ *  \returns 0 on success; negative on error */
+int sua_rx_msg(struct osmo_ss7_asp *asp, struct msgb *msg)
 {
-	struct osmo_scu_prim *prim;
-	struct sua_connection *conn;
-	struct osmo_scu_data_param *param;
-	struct xua_msg_part *data_ie = xua_msg_find_tag(xua, SUA_IEI_DATA);
-	struct msgb *upmsg;
-	uint32_t conn_id = xua_msg_get_u32(xua, SUA_IEI_DEST_REF);
-
-	/* resolve conn */
-	conn = conn_find_by_id(link, conn_id);
-	if (!conn) {
-		LOGP(DSUA, LOGL_ERROR, "DT1 for unknown reference %u\n",
-			conn_id);
-		/* FIXME: send error reply down the sua link? */
-		return -1;
-	}
-
-	if (conn->state != S_ACTIVE) {
-		LOGP(DSUA, LOGL_ERROR, "DT1 in invalid state %s\n",
-			get_value_string(conn_state_names, conn->state));
-		/* FIXME: send error reply down the sua link? */
-		return -1;
-	}
-
-	conn_restart_rx_inact_timer(conn);
-
-	/* fill primitive */
-	upmsg = sccp_msgb_alloc(__func__);
-	prim = (struct osmo_scu_prim *) msgb_put(upmsg, sizeof(*prim));
-	param = &prim->u.data;
-	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
-			OSMO_SCU_PRIM_N_DATA,
-			PRIM_OP_INDICATION, upmsg);
-	param->conn_id = conn_id;
-	param->importance = xua_msg_get_u32(xua, SUA_IEI_IMPORTANCE);
-
-	/* copy data */
-	upmsg->l2h = msgb_put(upmsg, data_ie->len);
-	memcpy(upmsg->l2h, data_ie->dat, data_ie->len);
-
-	/* send to user SAP */
-	link->user->prim_cb(&prim->oph, link);
-
-	return 0;
-}
+	struct xua_msg *xua = NULL, *err = NULL;
+	int rc = 0;
 
+	OSMO_ASSERT(asp->cfg.proto == OSMO_SS7_ASP_PROT_SUA);
 
-/* connection-oriented messages received from socket */
-static int sua_rx_co(struct osmo_sccp_link *link,
-		     struct xua_msg *xua, struct msgb *msg)
-{
-	int rc = -1;
+	/* caller owns msg memory, we shall neither free it here nor
+	 * keep references beyon the execution of this function and its
+	 * callees. */
 
-	switch (xua->hdr.msg_type) {
-	case SUA_CO_CORE:
-		rc = sua_rx_core(link, xua);
-		break;
-	case SUA_CO_COAK:
-		rc = sua_rx_coak(link, xua);
-		break;
-	case SUA_CO_COREF:
-		rc = sua_rx_coref(link, xua);
-		break;
-	case SUA_CO_RELRE:
-		rc = sua_rx_relre(link, xua);
-		break;
-	case SUA_CO_RELCO:
-		rc = sua_rx_relco(link, xua);
-		break;
-	case SUA_CO_CODT:
-		rc = sua_rx_codt(link, xua);
-		break;
-	case SUA_CO_RESCO:
-	case SUA_CO_RESRE:
-	case SUA_CO_CODA:
-	case SUA_CO_COERR:
-	case SUA_CO_COIT:
-		/* FIXME */
-	default:
-		break;
+	if (!asp->inst->sccp) {
+		LOGP(DLSUA, LOGL_ERROR, "%s(asp->inst->sccp=NULL)\n", __func__);
+		return -EIO;
 	}
 
-	return rc;
-}
-
-/* process SUA message received from socket */
-static int sua_rx_msg(struct osmo_sccp_link *link, struct msgb *msg)
-{
-	struct xua_msg *xua;
-	int rc = -1;
-
 	xua = xua_from_msg(1, msgb_length(msg), msg->data);
 	if (!xua) {
-		LOGP(DSUA, LOGL_ERROR, "Unable to parse incoming "
+		struct xua_common_hdr *hdr = (struct xua_common_hdr *) msg->data;
+
+		LOGPASP(asp, DLSUA, LOGL_ERROR, "Unable to parse incoming "
 			"SUA message\n");
-		return -EIO;
+
+		if (hdr->version != SUA_VERSION)
+			err = sua_gen_error_msg(SUA_ERR_INVALID_VERSION, msg);
+		else
+			err = sua_gen_error_msg(SUA_ERR_PARAM_FIELD_ERR, msg);
+		goto out;
 	}
 
-	LOGP(DSUA, LOGL_DEBUG, "Received SUA Message (%s)\n",
+#if 0
+	xua->mtp.opc = ;
+	xua->mtp.dpc = ;
+#endif
+	xua->mtp.sio = MTP_SI_SCCP;
+
+	LOGPASP(asp, DLSUA, LOGL_DEBUG, "Received SUA Message (%s)\n",
 		xua_hdr_dump(xua, &xua_dialect_sua));
 
-	if (!xua_dialect_check_all_mand_ies(&xua_dialect_sua, xua))
-		return -1;
+	if (!xua_dialect_check_all_mand_ies(&xua_dialect_sua, xua)) {
+		/* FIXME: Return error? */
+		err = sua_gen_error_msg(SUA_ERR_MISSING_PARAM, msg);
+		goto out;
+	}
+
+	/* TODO: check for SCTP Strema ID */
+	/* TODO: check if any AS configured in ASP */
+	/* TODO: check for valid routing context */
 
 	switch (xua->hdr.msg_class) {
 	case SUA_MSGC_CL:
-		rc = sua_rx_cl(link, xua, msg);
+		rc = sua_rx_cl(asp, xua);
 		break;
 	case SUA_MSGC_CO:
-		rc = sua_rx_co(link, xua, msg);
+		rc = sua_rx_co(asp, xua);
 		break;
-	case SUA_MSGC_MGMT:
-	case SUA_MSGC_SNM:
 	case SUA_MSGC_ASPSM:
 	case SUA_MSGC_ASPTM:
-	case SUA_MSGC_RKM:
-		/* FIXME */
-	default:
-		break;
-	}
-
-	xua_msg_free(xua);
-
-	return rc;
-}
-
-/***********************************************************************
- * libosmonetif integration
- ***********************************************************************/
-
-#include <osmocom/netif/stream.h>
-#include <netinet/sctp.h>
-
-static const struct value_string sctp_assoc_chg_vals[] = {
-	{ SCTP_COMM_UP, "COMM_UP" },
-	{ SCTP_COMM_LOST, "COMM_LOST" },
-	{ SCTP_RESTART, "RESTART" },
-	{ SCTP_SHUTDOWN_COMP, "SHUTDOWN_COMP" },
-	{ SCTP_CANT_STR_ASSOC, "CANT_STR_ASSOC" },
-	{ 0, NULL }
-};
-
-static const struct value_string sctp_sn_type_vals[] = {
-	{ SCTP_ASSOC_CHANGE,		"ASSOC_CHANGE" },
-	{ SCTP_PEER_ADDR_CHANGE,	"PEER_ADDR_CHANGE" },
-	{ SCTP_SHUTDOWN_EVENT, 		"SHUTDOWN_EVENT" },
-	{ SCTP_SEND_FAILED,		"SEND_FAILED" },
-	{ SCTP_REMOTE_ERROR,		"REMOTE_ERROR" },
-	{ SCTP_PARTIAL_DELIVERY_EVENT,	"PARTIAL_DELIVERY_EVENT" },
-	{ SCTP_ADAPTATION_INDICATION,	"ADAPTATION_INDICATION" },
-#ifdef SCTP_AUTHENTICATION_INDICATION
-	{ SCTP_AUTHENTICATION_INDICATION, "UTHENTICATION_INDICATION" },
-#endif
-#ifdef SCTP_SENDER_DRY_EVENT
-	{ SCTP_SENDER_DRY_EVENT,	"SENDER_DRY_EVENT" },
-#endif
-	{ 0, NULL }
-};
-
-static int get_logevel_by_sn_type(int sn_type)
-{
-	switch (sn_type) {
-	case SCTP_ADAPTATION_INDICATION:
-	case SCTP_PEER_ADDR_CHANGE:
-#ifdef SCTP_AUTHENTICATION_INDICATION
-	case SCTP_AUTHENTICATION_INDICATION:
-#endif
-#ifdef SCTP_SENDER_DRY_EVENT
-	case SCTP_SENDER_DRY_EVENT:
-#endif
-		return LOGL_INFO;
-	case SCTP_ASSOC_CHANGE:
-		return LOGL_NOTICE;
-	case SCTP_SHUTDOWN_EVENT:
-	case SCTP_PARTIAL_DELIVERY_EVENT:
-		return LOGL_NOTICE;
-	case SCTP_SEND_FAILED:
-	case SCTP_REMOTE_ERROR:
-		return LOGL_ERROR;
-	default:
-		return LOGL_NOTICE;
-	}
-}
-
-static void log_sctp_notification(int fd, const char *pfx,
-				  union sctp_notification *notif)
-{
-	int log_level;
-	char *conn_id = osmo_sock_get_name(NULL, fd);
-
-	LOGP(DSUA, LOGL_INFO, "%s %s SCTP NOTIFICATION %u flags=0x%0x\n",
-		conn_id, pfx, notif->sn_header.sn_type,
-		notif->sn_header.sn_flags);
-
-	log_level = get_logevel_by_sn_type(notif->sn_header.sn_type);
-
-	switch (notif->sn_header.sn_type) {
-	case SCTP_ASSOC_CHANGE:
-		LOGP(DSUA, log_level, "%s %s SCTP_ASSOC_CHANGE: %s\n",
-			conn_id, pfx, get_value_string(sctp_assoc_chg_vals,
-				notif->sn_assoc_change.sac_state));
+		rc = sua_rx_asp(asp, xua);
 		break;
-	default:
-		LOGP(DSUA, log_level, "%s %s %s\n",
-			conn_id, pfx, get_value_string(sctp_sn_type_vals,
-				notif->sn_header.sn_type));
+	case SUA_MSGC_MGMT:
+		rc = sua_rx_mgmt(asp, xua);
 		break;
-	}
-
-	talloc_free(conn_id);
-}
-
-/* netif code tells us we can read something from the socket */
-static int sua_srv_conn_cb(struct osmo_stream_srv *conn)
-{
-	struct osmo_fd *ofd = osmo_stream_srv_get_ofd(conn);
-	struct osmo_sccp_link *link = osmo_stream_srv_get_data(conn);
-	struct msgb *msg = msgb_alloc(SUA_MSGB_SIZE, "SUA Server Rx");
-	struct sctp_sndrcvinfo sinfo;
-	unsigned int ppid;
-	int flags = 0;
-	int rc;
-
-	if (!msg)
-		return -ENOMEM;
-
-	/* read SUA message from socket and process it */
-	rc = sctp_recvmsg(ofd->fd, msgb_data(msg), msgb_tailroom(msg),
-			  NULL, NULL, &sinfo, &flags);
-	LOGP(DSUA, LOGL_DEBUG, "sua_srv_conn_cb(): sctp_recvmsg() returned %d\n",
-	     rc);
-	if (rc < 0) {
-		close(ofd->fd);
-		osmo_fd_unregister(ofd);
-		ofd->fd = -1;
-		return rc;
-	} else if (rc == 0) {
-		close(ofd->fd);
-		osmo_fd_unregister(ofd);
-		ofd->fd = -1;
-	} else {
-		msgb_put(msg, rc);
-	}
-
-	if (flags & MSG_NOTIFICATION) {
-		union sctp_notification *notif = (union sctp_notification *) msgb_data(msg);
-
-		log_sctp_notification(ofd->fd, "SUA SRV", notif);
-
-		switch (notif->sn_header.sn_type) {
-		case SCTP_SHUTDOWN_EVENT:
-			close(ofd->fd);
-			osmo_fd_unregister(ofd);
-			ofd->fd = -1;
-			break;
-		default:
-			break;
-		}
-		msgb_free(msg);
-		return 0;
-	}
-
-	ppid = ntohl(sinfo.sinfo_ppid);
-	msgb_sctp_ppid(msg) = ppid;
-	msgb_sctp_stream(msg) = ntohl(sinfo.sinfo_stream);
-	msg->dst = link;
-
-	switch (ppid) {
-	case SUA_PPID:
-		rc = sua_rx_msg(link, msg);
+	case SUA_MSGC_SNM:
+	case SUA_MSGC_RKM:
+		/* FIXME */
+		LOGPASP(asp, DLSUA, LOGL_NOTICE, "Received unsupported SUA "
+			"Message Class %u\n", xua->hdr.msg_class);
+		err = sua_gen_error_msg(SUA_ERR_UNSUPP_MSG_CLASS, msg);
 		break;
 	default:
-		LOGP(DSUA, LOGL_NOTICE, "SCTP chunk for unknown PPID %u "
-			"received\n", ppid);
-		rc = 0;
+		LOGPASP(asp, DLSUA, LOGL_NOTICE, "Received unknown SUA "
+			"Message Class %u\n", xua->hdr.msg_class);
+		err = sua_gen_error_msg(SUA_ERR_UNSUPP_MSG_CLASS, msg);
 		break;
 	}
 
-	msgb_free(msg);
-	return rc;
-}
-
-static int sua_srv_conn_closed_cb(struct osmo_stream_srv *srv)
-{
-	struct osmo_sccp_link *sual = osmo_stream_srv_get_data(srv);
-	struct sua_connection *conn;
-
-	LOGP(DSUA, LOGL_INFO, "SCTP connection closed\n");
-
-	/* remove from per-user list of sua links */
-	llist_del(&sual->list);
-
-	llist_for_each_entry(conn, &sual->connections, list) {
-		/* FIXME: send RELEASE request */
-	}
-	talloc_free(sual);
-	osmo_stream_srv_set_data(srv, NULL);
-
-	return 0;
-}
-
-static int sua_accept_cb(struct osmo_stream_srv_link *link, int fd)
-{
-	struct osmo_sccp_user *user = osmo_stream_srv_link_get_data(link);
-	struct osmo_stream_srv *srv;
-	struct osmo_sccp_link *sual;
-
-	LOGP(DSUA, LOGL_INFO, "New SCTP connection accepted\n");
-
-	srv = osmo_stream_srv_create(user, link, fd,
-				     sua_srv_conn_cb,
-				     sua_srv_conn_closed_cb, NULL);
-	if (!srv) {
-		close(fd);
-		return -1;
-	}
-
-	/* create new SUA link and connect both data structures */
-	sual = sua_link_new(user, 1);
-	if (!sual) {
-		osmo_stream_srv_destroy(srv);
-		return -1;
-	}
-	sual->data = srv;
-	osmo_stream_srv_set_data(srv, sual);
-
-	return 0;
-}
-
-int osmo_sua_server_listen(struct osmo_sccp_user *user, const char *hostname, uint16_t port)
-{
-	int rc;
-
-	if (user->server)
-		osmo_stream_srv_link_close(user->server);
-	else {
-		user->server = osmo_stream_srv_link_create(user);
-		osmo_stream_srv_link_set_data(user->server, user);
-		osmo_stream_srv_link_set_accept_cb(user->server, sua_accept_cb);
-	}
-
-	osmo_stream_srv_link_set_addr(user->server, hostname);
-	osmo_stream_srv_link_set_port(user->server, port);
-	osmo_stream_srv_link_set_proto(user->server, IPPROTO_SCTP);
-
-	rc = osmo_stream_srv_link_open(user->server);
-	if (rc < 0) {
-		osmo_stream_srv_link_destroy(user->server);
-		user->server = NULL;
-		return rc;
-	}
-
-	return 0;
-}
-
-/* netif code tells us we can read something from the socket */
-static int sua_cli_read_cb(struct osmo_stream_cli *conn)
-{
-	struct osmo_fd *ofd = osmo_stream_cli_get_ofd(conn);
-	struct osmo_sccp_link *link = osmo_stream_cli_get_data(conn);
-	struct msgb *msg = msgb_alloc(SUA_MSGB_SIZE, "SUA Client Rx");
-	struct sctp_sndrcvinfo sinfo;
-	unsigned int ppid;
-	int flags = 0;
-	int rc;
-
-	LOGP(DSUA, LOGL_DEBUG, "sua_cli_read_cb() rx\n");
-
-	if (!msg)
-		return -ENOMEM;
-
-	/* read SUA message from socket and process it */
-	rc = sctp_recvmsg(ofd->fd, msgb_data(msg), msgb_tailroom(msg),
-			  NULL, NULL, &sinfo, &flags);
-	if (rc < 0) {
-		close(ofd->fd);
-		osmo_fd_unregister(ofd);
-		ofd->fd = -1;
-		return rc;
-	} else if (rc == 0) {
-		close(ofd->fd);
-		osmo_fd_unregister(ofd);
-		ofd->fd = -1;
-	} else {
-		msgb_put(msg, rc);
-	}
-
-	if (flags & MSG_NOTIFICATION) {
-		union sctp_notification *notif = (union sctp_notification *) msgb_data(msg);
+	if (rc > 0)
+		err = sua_gen_error_msg(rc, msg);
 
-		log_sctp_notification(ofd->fd, "SUA CLNT", notif);
+out:
+	if (err)
+		sua_tx_xua_asp(asp, err);
 
-		switch (notif->sn_header.sn_type) {
-		case SCTP_SHUTDOWN_EVENT:
-			close(ofd->fd);
-			osmo_fd_unregister(ofd);
-			ofd->fd = -1;
-			break;
-		default:
-			break;
-		}
-		msgb_free(msg);
-		return 0;
-	}
-
-	ppid = ntohl(sinfo.sinfo_ppid);
-	msgb_sctp_ppid(msg) = ppid;
-	msgb_sctp_stream(msg) = ntohl(sinfo.sinfo_stream);
-	msg->dst = link;
-
-	switch (ppid) {
-	case SUA_PPID:
-		rc = sua_rx_msg(link, msg);
-		break;
-	default:
-		LOGP(DSUA, LOGL_NOTICE, "SCTP chunk for unknown PPID %u "
-			"received\n", ppid);
-		rc = 0;
-		break;
-	}
+	xua_msg_free(xua);
 
-	msgb_free(msg);
 	return rc;
 }
 
-int osmo_sua_client_connect(struct osmo_sccp_user *user, const char *hostname, uint16_t port)
-{
-	struct osmo_stream_cli *cli;
-	struct osmo_sccp_link *sual;
-	int rc;
-
-	cli = osmo_stream_cli_create(user);
-	if (!cli)
-		return -1;
-	osmo_stream_cli_set_addr(cli, hostname);
-	osmo_stream_cli_set_port(cli, port);
-	osmo_stream_cli_set_proto(cli, IPPROTO_SCTP);
-	osmo_stream_cli_set_reconnect_timeout(cli, 5);
-	osmo_stream_cli_set_read_cb(cli, sua_cli_read_cb);
-
-	/* create SUA link and associate it with stream_cli */
-	sual = sua_link_new(user, 0);
-	if (!sual) {
-		osmo_stream_cli_destroy(cli);
-		return -1;
-	}
-	sual->data = cli;
-	osmo_stream_cli_set_data(cli, sual);
-
-	rc = osmo_stream_cli_open2(cli, 1);
-	if (rc < 0) {
-		sua_link_destroy(sual);
-		osmo_stream_cli_destroy(cli);
-		return rc;
-	}
-	user->client = cli;
-
-	return 0;
-}
-
-struct osmo_sccp_link *osmo_sua_client_get_link(struct osmo_sccp_user *user)
-{
-	return osmo_stream_cli_get_data(user->client);
-}
-
-static LLIST_HEAD(sua_users);
-
-struct osmo_sccp_user *osmo_sua_user_create(void *ctx, osmo_prim_cb prim_cb,
-					    void *priv)
-{
-	struct osmo_sccp_user *user = talloc_zero(ctx, struct osmo_sccp_user);
-
-	user->prim_cb = prim_cb;
-	user->priv = priv;
-	INIT_LLIST_HEAD(&user->links);
-
-	llist_add_tail(&user->list, &sua_users);
-
-	return user;
-}
-
-void *osmo_sccp_link_get_user_priv(struct osmo_sccp_link *slink)
-{
-	return slink->user->priv;
-}
-
-void osmo_sua_user_destroy(struct osmo_sccp_user *user)
-{
-	struct osmo_sccp_link *link;
-
-	llist_del(&user->list);
-
-	llist_for_each_entry(link, &user->links, list)
-		sua_link_destroy(link);
-
-	talloc_free(user);
-}
-
-void osmo_sua_set_log_area(int area)
-{
-	xua_set_log_area(area);
-	DSUA = area;
-}