142 lines
4.5 KiB
Plaintext
142 lines
4.5 KiB
Plaintext
module MSC_ConnectionHandler {
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import from General_Types all;
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import from Osmocom_Types all;
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import from SCCPasp_Types all;
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import from BSSAP_Types all;
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import from BSSMAP_Emulation all;
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import from BSSMAP_Templates all;
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import from MGCP_Types all;
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import from MGCP_Templates all;
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import from SDP_Types all;
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/* this component represents a single subscriber connection at the MSC.
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* There is a 1:1 mapping between SCCP connections and BSSAP_ConnHdlr components.
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* We inherit all component variables, ports, functions, ... from BSSAP_ConnHdlr */
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type component MSC_ConnHdlr extends BSSAP_ConnHdlr {
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/* SCCP Connecction Identifier for the underlying SCCP connection */
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var integer g_sccp_conn_id;
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var MSC_State g_state := MSC_STATE_NONE;
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var MgcpEndpoint g_ep_name;
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var MgcpCallId g_call_id;
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var MgcpConnectionId g_mgcp_conn_id;
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}
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/* Callback function from general BSSMAP_Emulation whenever a new incoming
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* SCCP connection arrivces. Must create + start a new component */
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private function CreateCallback(ASP_SCCP_N_CONNECT_ind conn_ind, charstring id)
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runs on BSSMAP_Emulation_CT return BSSAP_ConnHdlr {
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var MSC_ConnHdlr vc_conn;
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/* Create a new BSSAP_ConnHdlr component */
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vc_conn := MSC_ConnHdlr.create(g_bssmap_id & "-Conn-" & int2str(conn_ind.connectionId));
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/* connect it to the port */
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connect(vc_conn:BSSAP, self:CLIENT);
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/* start it */
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vc_conn.start(MSC_ConnectionHandler.main(conn_ind.connectionId, g_next_e1_ts));
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/* increment next E1 timeslot */
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g_next_e1_ts := g_next_e1_ts + 1;
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return vc_conn;
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}
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/* Callback function from general BSSMAP_Emulation whenever a connectionless
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* BSSMAP message arrives. Can retunr a PDU_BSSAP that should be sent in return */
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private function UnitdataCallback(PDU_BSSAP bssap)
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runs on BSSMAP_Emulation_CT return template PDU_BSSAP {
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var template PDU_BSSAP resp := omit;
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if (match(bssap, tr_BSSMAP_Reset)) {
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resp := ts_BSSMAP_ResetAck;
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}
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return resp;
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}
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const BssmapOps MSC_BssmapOps := {
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create_cb := refers(CreateCallback),
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unitdata_cb := refers(UnitdataCallback)
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}
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type enumerated MSC_State {
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MSC_STATE_NONE,
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MSC_STATE_WAIT_ASS_COMPL,
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MSC_STATE_WAIT_CRCX_ACK,
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MSC_STATE_WAIT_MDCX_ACK,
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MSC_STATE_WAIT_CLEAR_COMPL,
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MSC_STATE_WAIT_DLCX_ACK
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}
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/* main function processing various incoming events */
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function main(integer connection_id, integer e1_timeslot) runs on MSC_ConnHdlr {
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var MgcpResponse mgcp_rsp;
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g_sccp_conn_id := connection_id;
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g_call_id := f_mgcp_alloc_call_id();
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g_ep_name := hex2str(int2hex(e1_timeslot, 1)) & "@mgw";
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while (true) {
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var PDU_BSSAP bssap;
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alt {
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/* new SCCP-level connection indication from BSC */
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[g_state == MSC_STATE_NONE] BSSAP.receive(tr_BSSMAP_ComplL3) -> value bssap {
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/* respond with ASSIGNMENT CMD */
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g_state := MSC_STATE_WAIT_ASS_COMPL;
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BSSAP.send(ts_BSSMAP_AssignmentReq(0, e1_timeslot));
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}
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[g_state == MSC_STATE_WAIT_ASS_COMPL] BSSAP.receive(tr_BSSMAP_AssignmentComplete) {
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/* FIXME: Send MGCP CRCX */
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g_state := MSC_STATE_WAIT_CRCX_ACK;
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var MgcpTransId trans_id := f_mgcp_alloc_tid();
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//template SDP_Message sdp := omit;
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BSSAP.send(ts_CRCX(trans_id, g_ep_name, "recvonly", g_call_id)); //, sdp));
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}
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/*
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[] BSSAP.receive(tr_BSSMAP_AssignmentFail) {
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}
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*/
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/* receive CRCX ACK: transmit MDCX */
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[g_state == MSC_STATE_WAIT_CRCX_ACK] BSSAP.receive(tr_CRCX_ACK) -> value mgcp_rsp {
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/* extract connection ID */
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g_mgcp_conn_id := f_MgcpResp_extract_conn_id(mgcp_rsp);
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g_state := MSC_STATE_WAIT_MDCX_ACK;
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var MgcpTransId trans_id := f_mgcp_alloc_tid();
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BSSAP.send(ts_MDCX(trans_id, g_ep_name, "sendrecv", g_call_id, g_mgcp_conn_id));
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}
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/* receive MDCX ACK: wait + transmit CLEAR COMMAND */
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[g_state == MSC_STATE_WAIT_MDCX_ACK] BSSAP.receive(tr_CRCX_ACK) -> value mgcp_rsp {
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g_state := MSC_STATE_WAIT_CLEAR_COMPL
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BSSAP.send(ts_BSSMAP_ClearCommand(9)); /* Cause: call control */
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}
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/* CLEAR COMPLETE from BSS (response to CLEAR COMMAND) */
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[g_state == MSC_STATE_WAIT_CLEAR_COMPL] BSSAP.receive(tr_BSSMAP_ClearComplete) {
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/* send DLCX */
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g_state := MSC_STATE_WAIT_DLCX_ACK;
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var MgcpTransId trans_id := f_mgcp_alloc_tid();
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BSSAP.send(ts_DLCX(trans_id, g_ep_name, g_call_id));
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}
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[g_state == MSC_STATE_WAIT_DLCX_ACK] BSSAP.receive(tr_DLCX_ACK) {
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setverdict(pass);
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self.stop;
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}
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/* TODO: CLEAR REQUEST from BSS */
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[] BSSAP.receive(BSSAP_Conn_Prim:MSC_CONN_PRIM_DISC_IND) {
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setverdict(fail);
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self.stop;
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}
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[] BSSAP.receive(PDU_BSSAP:?) -> value bssap {
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log("Received unhandled SCCP-CO: ", bssap);
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}
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}
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}
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}
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}
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