s1gw: add S1AP Server (dispatcher) component
Change-Id: Ib8a14c1a76c980f4d8a153461c9b63d205574573
Related: SYS#6772
diff --git a/s1gw/S1AP_Server.ttcn b/s1gw/S1AP_Server.ttcn
new file mode 100644
index 0000000..1128e76
--- /dev/null
+++ b/s1gw/S1AP_Server.ttcn
@@ -0,0 +1,436 @@
+module S1AP_Server {
+
+/* S1AP Server, runs on top of S1AP_CodecPort, accepting the S1AP
+ * connections and forwarding S1AP PDUs to/from the ConnHdlr components.
+ * A ConnHdlr component may subscribe for one or more S1AP connections
+ * using the Global_ENB_ID value, which is sent in S1AP SetupReq.
+ *
+ * (C) 2024 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * Author: Vadim Yanitskiy <vyanitskiy@sysmocom.de>
+ *
+ * All rights reserved.
+ *
+ * Released under the terms of GNU General Public License, Version 2 or
+ * (at your option) any later version.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+import from General_Types all;
+import from Osmocom_Types all;
+import from IPL4asp_Types all;
+
+import from S1AP_CodecPort all;
+import from S1AP_CodecPort_CtrlFunct all;
+import from S1AP_Types all;
+import from S1AP_Constants all;
+import from S1AP_PDU_Contents all;
+import from S1AP_PDU_Descriptions all;
+import from S1AP_IEs all;
+import from S1AP_Templates all;
+
+type enumerated S1APSRV_Event {
+ S1APSRV_EVENT_CONN_UP,
+ S1APSRV_EVENT_CONN_DOWN
+};
+
+type port S1APSRV_CONN_PT message {
+ inout S1AP_PDU, S1APSRV_Event;
+} with { extension "internal" };
+
+type component S1APSRV_ConnHdlr {
+ port S1APSRV_CONN_PT S1AP_CONN;
+ port S1APSRV_PROC_PT S1AP_PROC;
+};
+
+type record S1APSRV_ConnParams {
+ HostName local_ip,
+ PortNumber local_port
+};
+
+type component S1AP_Server_CT {
+ /* port facing to the SUT */
+ port S1AP_CODEC_PT S1AP;
+ /* all S1APSRV_ConnHdlr S1AP ports connect here */
+ port S1APSRV_CONN_PT S1AP_CLIENT;
+ /* procedure based port to register for incoming connections */
+ port S1APSRV_PROC_PT S1AP_PROC;
+
+ /* active eNB connections */
+ var ConnList g_conn_list;
+ /* registered ConnHdlr */
+ var ConnHdlrList g_conn_hdlr_list;
+
+ var S1APSRV_ConnParams g_cpars;
+ var ConnectionId g_s1ap_conn_id := -1;
+};
+
+
+/* represents a single eNB connection */
+private type record ConnData {
+ ConnectionId conn_id,
+ Global_ENB_ID genb_id /* can be unbound */
+};
+private type record of ConnData ConnList;
+
+/* represents a single ConnHdlr item */
+private type record ConnHdlrData {
+ S1APSRV_ConnHdlr vc_conn,
+ Global_ENB_ID genb_id,
+ ConnectionId conn_id /* can be -1 */
+};
+private type record of ConnHdlrData ConnHdlrList;
+
+private template (present) S1AP_RecvFrom
+tr_S1AP_RecvFrom_R(template (present) S1AP_PDU msg := ?,
+ template (present) ConnectionId conn_id := ?) := {
+ connId := conn_id,
+ remName := ?,
+ remPort := ?,
+ locName := ?,
+ locPort := ?,
+ msg := msg
+};
+
+template (value) SctpTuple ts_SCTP(template (omit) integer ppid := 18) := {
+ sinfo_stream := omit,
+ sinfo_ppid := ppid,
+ remSocks := omit,
+ assocId := omit
+};
+
+/***********************************************************************************
+ * Connection management API
+ **********************************************************************************/
+
+/* find a connection [index] by a connection ID */
+private function f_conn_find_by_conn_id(ConnectionId conn_id)
+runs on S1AP_Server_CT return integer {
+ for (var integer i := 0; i < lengthof(g_conn_list); i := i + 1) {
+ if (g_conn_list[i].conn_id == conn_id) {
+ return i;
+ }
+ }
+
+ return -1;
+}
+
+/* find a connection [index] by a global eNB ID */
+private function f_conn_find_by_genb_id(Global_ENB_ID genb_id)
+runs on S1AP_Server_CT return integer {
+ for (var integer i := 0; i < lengthof(g_conn_list); i := i + 1) {
+ if (isbound(g_conn_list[i].genb_id) and
+ g_conn_list[i].genb_id == genb_id) {
+ return i;
+ }
+ }
+
+ return -1;
+}
+
+/* add a new connection, return its index */
+private function f_conn_add(ConnectionId conn_id)
+runs on S1AP_Server_CT return integer {
+ var ConnData conn := { conn_id, - };
+ var integer idx;
+
+ if (f_conn_find_by_conn_id(conn_id) != -1) {
+ setverdict(fail, "Connection (id=", conn_id, ") is already added");
+ mtc.stop;
+ }
+
+ idx := lengthof(g_conn_list);
+ g_conn_list := g_conn_list & { conn };
+ log("Connection (id=", conn_id, ") is registered");
+
+ return idx;
+}
+
+/* del an existing connection */
+private function f_conn_del(ConnectionId conn_id)
+runs on S1AP_Server_CT {
+ var ConnList conn_list := { };
+
+ for (var integer i := 0; i < lengthof(g_conn_list); i := i + 1) {
+ if (g_conn_list[i].conn_id == conn_id) {
+ if (isbound(g_conn_list[i].genb_id)) {
+ f_ConnHdlr_update(g_conn_list[i].genb_id, -1);
+ }
+ } else {
+ conn_list := conn_list & { g_conn_list[i] };
+ }
+ }
+
+ if (lengthof(conn_list) == lengthof(g_conn_list)) {
+ setverdict(fail, "Connection (id=", conn_id, ") is not known");
+ mtc.stop;
+ }
+
+ g_conn_list := conn_list;
+ log("Connection (id=", conn_id, ") is deleted");
+}
+
+/* add a new connection, return its index */
+private function f_conn_set_genb_id(ConnectionId conn_id, Global_ENB_ID genb_id)
+runs on S1AP_Server_CT {
+ var integer idx;
+
+ if (f_conn_find_by_genb_id(genb_id) != -1) {
+ setverdict(fail, "Duplicate Global eNB ID ", genb_id);
+ mtc.stop;
+ }
+
+ idx := f_conn_find_by_conn_id(conn_id);
+ if (idx == -1) {
+ setverdict(fail, "Connection (id=", conn_id, ") is not known");
+ mtc.stop;
+ }
+
+ g_conn_list[idx].genb_id := genb_id;
+
+ f_ConnHdlr_update(genb_id, conn_id);
+}
+
+private function f_conn_close(ConnectionId conn_id)
+runs on S1AP_Server_CT {
+ log("Closing an eNB connection (id=", conn_id, ")");
+ S1AP_CodecPort_CtrlFunct.f_IPL4_close(S1AP, conn_id,
+ { sctp := valueof(ts_SCTP) });
+ f_conn_del(conn_id);
+}
+
+private function f_conn_close_by_genb_id(Global_ENB_ID genb_id)
+runs on S1AP_Server_CT {
+ var integer idx;
+
+ idx := f_conn_find_by_genb_id(genb_id);
+ if (idx == -1) {
+ setverdict(fail, "There is no connection for Global eNB ID ", genb_id);
+ mtc.stop;
+ }
+
+ f_conn_close(g_conn_list[idx].conn_id);
+}
+
+/***********************************************************************************
+ * ConnHdlr management API
+ **********************************************************************************/
+
+/* find a ConnHdlr [index] by a connection ID */
+private function f_ConnHdlr_find_by_conn_id(ConnectionId conn_id)
+runs on S1AP_Server_CT return integer {
+ for (var integer i := 0; i < lengthof(g_conn_hdlr_list); i := i + 1) {
+ if (g_conn_hdlr_list[i].conn_id == conn_id) {
+ return i;
+ }
+ }
+
+ return -1;
+}
+
+/* find a ConnHdlr [index] by a global eNB ID */
+private function f_ConnHdlr_find_by_genb_id(Global_ENB_ID genb_id)
+runs on S1AP_Server_CT return integer {
+ for (var integer i := 0; i < lengthof(g_conn_hdlr_list); i := i + 1) {
+ if (g_conn_hdlr_list[i].genb_id == genb_id) {
+ return i;
+ }
+ }
+
+ return -1;
+}
+
+/* find a ConnHdlr [index] by a component reference */
+private function f_ConnHdlr_find_by_vc_conn(S1APSRV_ConnHdlr vc_conn)
+runs on S1AP_Server_CT return integer {
+ for (var integer i := 0; i < lengthof(g_conn_hdlr_list); i := i + 1) {
+ if (g_conn_hdlr_list[i].vc_conn == vc_conn) {
+ return i;
+ }
+ }
+
+ return -1;
+}
+
+private function f_ConnHdlr_add(S1APSRV_ConnHdlr vc_conn, Global_ENB_ID genb_id)
+runs on S1AP_Server_CT {
+ var ConnectionId conn_id := -1;
+ var integer idx;
+
+ if (f_ConnHdlr_find_by_genb_id(genb_id) != -1) {
+ setverdict(fail, "Global eNB ID ", genb_id, " is already registered");
+ mtc.stop;
+ }
+
+ idx := f_conn_find_by_genb_id(genb_id);
+ if (idx != -1) {
+ conn_id := g_conn_list[idx].conn_id;
+ }
+
+ g_conn_hdlr_list := g_conn_hdlr_list & { {vc_conn, genb_id, conn_id} };
+ log("Global eNB ID ", genb_id, " has been registered");
+}
+
+private function f_ConnHdlr_del(integer idx)
+runs on S1AP_Server_CT {
+ var ConnHdlrList conn_hdlr_list := { };
+
+ for (var integer i := 0; i < lengthof(g_conn_hdlr_list); i := i + 1) {
+ if (i != idx) {
+ conn_hdlr_list := conn_hdlr_list & { g_conn_hdlr_list[i] };
+ }
+ }
+
+ g_conn_hdlr_list := conn_hdlr_list;
+}
+
+private function f_ConnHdlr_del_by_genb_id(Global_ENB_ID genb_id)
+runs on S1AP_Server_CT {
+ var integer idx;
+
+ idx := f_ConnHdlr_find_by_genb_id(genb_id);
+ if (idx == -1) {
+ setverdict(fail, "Global eNB ID ", genb_id, " is not registered");
+ mtc.stop;
+ }
+
+ f_ConnHdlr_del(idx);
+ log("Global eNB ID ", genb_id, " has been unregistered");
+}
+
+private function f_ConnHdlr_update(Global_ENB_ID genb_id, ConnectionId conn_id)
+runs on S1AP_Server_CT {
+ for (var integer i := 0; i < lengthof(g_conn_hdlr_list); i := i + 1) {
+ if (g_conn_hdlr_list[i].genb_id == genb_id) {
+ g_conn_hdlr_list[i].conn_id := conn_id;
+ /* notify the ConnHdlr about connection state */
+ var S1APSRV_Event ev;
+ if (conn_id == -1) {
+ ev := S1APSRV_EVENT_CONN_DOWN;
+ } else {
+ ev := S1APSRV_EVENT_CONN_UP;
+ }
+ S1AP_CLIENT.send(ev) to g_conn_hdlr_list[i].vc_conn;
+ }
+ }
+}
+
+signature S1APSRV_register(in S1APSRV_ConnHdlr vc_conn, in Global_ENB_ID genb_id);
+signature S1APSRV_unregister(in S1APSRV_ConnHdlr vc_conn, in Global_ENB_ID genb_id);
+signature S1APSRV_close_conn(in S1APSRV_ConnHdlr vc_conn, in Global_ENB_ID genb_id);
+
+type port S1APSRV_PROC_PT procedure {
+ inout S1APSRV_register;
+ inout S1APSRV_unregister;
+ inout S1APSRV_close_conn;
+} with { extension "internal" };
+
+function f_ConnHdlr_register(Global_ENB_ID genb_id)
+runs on S1APSRV_ConnHdlr {
+ S1AP_PROC.call(S1APSRV_register:{self, genb_id}) {
+ [] S1AP_PROC.getreply(S1APSRV_register:{?, ?}) { };
+ }
+}
+
+function f_ConnHdlr_unregister(Global_ENB_ID genb_id)
+runs on S1APSRV_ConnHdlr {
+ S1AP_PROC.call(S1APSRV_unregister:{self, genb_id}) {
+ [] S1AP_PROC.getreply(S1APSRV_unregister:{?, ?}) { };
+ }
+}
+
+function f_ConnHdlr_close_conn(Global_ENB_ID genb_id)
+runs on S1APSRV_ConnHdlr {
+ S1AP_PROC.call(S1APSRV_close_conn:{self, genb_id}) {
+ [] S1AP_PROC.getreply(S1APSRV_close_conn:{?, ?}) { };
+ }
+}
+
+function main(S1APSRV_ConnParams cpars) runs on S1AP_Server_CT {
+ var Result res;
+
+ g_cpars := cpars;
+ g_conn_list := { };
+ g_conn_hdlr_list := { };
+
+ map(self:S1AP, system:S1AP_CODEC_PT);
+ res := S1AP_CodecPort_CtrlFunct.f_IPL4_listen(S1AP,
+ cpars.local_ip, cpars.local_port,
+ { sctp := valueof(ts_SCTP) });
+ if (not ispresent(res.connId)) {
+ setverdict(fail, "Could not create an S1AP socket, check your configuration");
+ mtc.stop;
+ }
+ g_s1ap_conn_id := res.connId;
+
+ log("SCTP server listening on ", cpars.local_ip, ":", cpars.local_port);
+
+ while (true) {
+ var S1APSRV_ConnHdlr vc_conn;
+ var S1AP_RecvFrom mrf;
+ var S1AP_PDU msg;
+
+ var Global_ENB_ID genb_id;
+ var PortEvent pev;
+
+ alt {
+ /* S1AP PDU from a peer (eNB) */
+ [] S1AP.receive(tr_S1AP_RecvFrom_R) -> value mrf {
+ if (match(mrf.msg, tr_S1AP_SetupReq)) {
+ genb_id := mrf.msg.initiatingMessage.value_.S1SetupRequest.protocolIEs[0].value_.Global_ENB_ID;
+ f_conn_set_genb_id(mrf.connId, genb_id);
+ }
+ var integer idx := f_ConnHdlr_find_by_conn_id(mrf.connId);
+ if (idx != -1) {
+ S1AP_CLIENT.send(mrf.msg) to g_conn_hdlr_list[idx].vc_conn;
+ } /* else: no ConnHdlr, drop PDU */
+ }
+ /* S1AP PDU from a ConnHdlr: pass on transparently */
+ [] S1AP_CLIENT.receive(S1AP_PDU:?) -> value msg sender vc_conn {
+ var integer idx := f_ConnHdlr_find_by_vc_conn(vc_conn);
+ if (idx == -1) {
+ setverdict(fail, "Component ", vc_conn, " is not registered");
+ mtc.stop;
+ }
+ if (g_conn_hdlr_list[idx].conn_id == -1) {
+ setverdict(fail, "S1AP connection is not up");
+ mtc.stop;
+ }
+ S1AP.send(t_S1AP_Send(g_conn_hdlr_list[idx].conn_id, msg));
+ }
+
+ /* connection opened/closed events */
+ [] S1AP.receive(PortEvent:{connOpened := ?}) -> value pev {
+ log("eNB connection (id=", pev.connOpened.connId, ", ",
+ pev.connOpened.remName, ":", pev.connOpened.remPort, ") ",
+ "established");
+ f_conn_add(pev.connOpened.connId);
+ }
+ [] S1AP.receive(PortEvent:{connClosed := ?}) -> value pev {
+ log("eNB connection (id=", pev.connClosed.connId, ", ",
+ pev.connClosed.remName, ":", pev.connClosed.remPort, ") ",
+ "closed");
+ f_conn_del(pev.connClosed.connId);
+ }
+
+ /* SCTP events we don't care about */
+ [] S1AP.receive(PortEvent:{sctpEvent := ?}) { }
+
+ /* ConnHdlr registration/unregistration */
+ [] S1AP_PROC.getcall(S1APSRV_register:{?, ?}) -> param(vc_conn, genb_id) {
+ f_ConnHdlr_add(vc_conn, genb_id);
+ S1AP_PROC.reply(S1APSRV_register:{vc_conn, genb_id}) to vc_conn;
+ }
+ [] S1AP_PROC.getcall(S1APSRV_unregister:{?, ?}) -> param(vc_conn, genb_id) {
+ f_ConnHdlr_del_by_genb_id(genb_id);
+ S1AP_PROC.reply(S1APSRV_unregister:{vc_conn, genb_id}) to vc_conn;
+ }
+ [] S1AP_PROC.getcall(S1APSRV_close_conn:{?, ?}) -> param(vc_conn, genb_id) {
+ f_conn_close_by_genb_id(genb_id);
+ S1AP_PROC.reply(S1APSRV_close_conn:{vc_conn, genb_id}) to vc_conn;
+ }
+ }
+ }
+}
+
+}