212 lines
6.6 KiB
Plaintext
212 lines
6.6 KiB
Plaintext
module MSC_ConnectionHandler {
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/* (C) 2017-2019 Harald Welte <laforge@gnumonks.org>
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* All rights reserved.
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*
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* Released under the terms of GNU General Public License, Version 2 or
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* (at your option) any later version.
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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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 BSSAP_CodecPort all;
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import from RAN_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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type function void_fn_msc(charstring id) runs on MSC_ConnHdlr;
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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 RAN_ConnHdlr components.
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* We inherit all component variables, ports, functions, ... from RAN_ConnHdlr */
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type component MSC_ConnHdlr extends RAN_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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var MSC_TestHdlrParams g_pars;
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}
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type record MSC_TestHdlrParams {
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integer connection_id,
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integer e1_timeslot
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};
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/* helper function to create and connect a MSC_ConnHdlr component */
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private function f_connect_handler(inout MSC_ConnHdlr vc_conn) runs on RAN_Emulation_CT {
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/* connect client BSSAP port to BSSAP dispatcher */
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connect(vc_conn:BSSAP, self:CLIENT);
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}
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private function f_msc_start_handler(void_fn_msc fn, charstring id, template (omit) MSC_TestHdlrParams pars := omit)
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runs on RAN_Emulation_CT return MSC_ConnHdlr {
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var MSC_ConnHdlr vc_conn;
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vc_conn := MSC_ConnHdlr.create(id);
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f_connect_handler(vc_conn);
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vc_conn.start(f_handler_init(fn, id, pars));
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return vc_conn;
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}
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/* first function inside ConnHdlr component; sets g_pars + starts function */
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private function f_handler_init(void_fn_msc fn, charstring id, template (omit) MSC_TestHdlrParams pars := omit)
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runs on MSC_ConnHdlr {
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if (isvalue(pars)) {
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g_pars := valueof(pars);
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}
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fn.apply(id);
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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 RAN_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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/* 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_generic(void_fn_msc fn, BSSAP_N_CONNECT_ind conn_ind, charstring id)
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runs on RAN_Emulation_CT return RAN_ConnHdlr {
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var MSC_ConnHdlr vc_conn;
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var MSC_TestHdlrParams pars;
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pars.connection_id := conn_ind.connectionId;
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pars.e1_timeslot := g_next_e1_ts;
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/* Create a new RAN_ConnHdlr component */
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vc_conn := f_msc_start_handler(fn, g_ran_id & "-Conn-" & int2str(conn_ind.connectionId), pars);
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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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const RanOps MSC_RanOps := {
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create_cb := omit,
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unitdata_cb := refers(UnitdataCallback),
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decode_dtap := false,
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role_ms := false,
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protocol := RAN_PROTOCOL_BSSAP,
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transport := BSSAP_TRANSPORT_AoIP,
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use_osmux := false,
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bssap_reset_retries := 1,
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sccp_addr_local := omit,
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sccp_addr_peer := omit
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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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/* 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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function CreateCallback_establish_fully(BSSAP_N_CONNECT_ind conn_ind, charstring id)
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runs on RAN_Emulation_CT return RAN_ConnHdlr {
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return CreateCallback_generic(refers(f_msc_establish_fully), conn_ind, id);
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}
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/* main function processing various incoming events */
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function f_msc_establish_fully(charstring id) runs on MSC_ConnHdlr {
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var MgcpResponse mgcp_rsp;
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timer T := 5.0;
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g_sccp_conn_id := g_pars.connection_id;
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g_call_id := f_mgcp_alloc_call_id();
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g_ep_name := hex2str(int2hex(g_pars.e1_timeslot, 1)) & "@mgw";
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/* we just accepted an incoming SCCP connection, start guard timer */
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T.start;
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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(ts_BSSMAP_IE_CIC(0, g_pars.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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BSSAP.send(RAN_Conn_Prim:MSC_CONN_PRIM_DISC_REQ);
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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(RAN_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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/* Guard timer has expired, close connection */
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[] T.timeout {
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BSSAP.send(RAN_Conn_Prim:MSC_CONN_PRIM_DISC_REQ);
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setverdict(fail, "Timeout of guard timer");
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self.stop;
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}
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}
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}
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}
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}
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