bsc/MSC_ConnectionHandler.ttcn

module MSC_ConnectionHandler {

import from General_Types all;
import from Osmocom_Types all;
import from GSM_Types all;
import from SCCPasp_Types all;
import from BSSAP_Types all;
import from BSSMAP_Emulation all;
import from BSSMAP_Templates all;

import from MGCP_Types all;
import from MGCP_Templates all;
import from SDP_Types all;

import from RSL_Emulation all;
import from RSL_Types all;

import from MobileL3_Types all;
import from MobileL3_CommonIE_Types all;
//import from MobileL3_RRM_Types all;
import from L3_Templates all;


/* this component represents a single subscriber connection at the MSC.
 * There is a 1:1 mapping between SCCP connections and BSSAP_ConnHdlr components.
 * We inherit all component variables, ports, functions, ... from BSSAP_ConnHdlr */
type component MSC_ConnHdlr extends BSSAP_ConnHdlr, RSL_DchanHdlr {
	/* SCCP Connecction Identifier for the underlying SCCP connection */
	var integer g_sccp_conn_id;

	/* procedure port back to our parent (BSSMAP_Emulation_CT) for control */
	port BSSMAPEM_PROC_PT BSSMAPEM;

	var MSC_State g_state := MSC_STATE_NONE;
}

/* Callback function from general BSSMAP_Emulation whenever a connectionless
 * BSSMAP message arrives.  Can retunr a PDU_BSSAP that should be sent in return */
private function UnitdataCallback(PDU_BSSAP bssap)
runs on BSSMAP_Emulation_CT return template PDU_BSSAP {
	var template PDU_BSSAP resp := omit;

	/* answer all RESET with a RESET ACK */
	if (match(bssap, tr_BSSMAP_Reset)) {
		resp := ts_BSSMAP_ResetAck;
	}

	return resp;
}

const BssmapOps MSC_BssmapOps := {
	create_cb := refers(BSSMAP_Emulation.ExpectedCreateCallback),
	unitdata_cb := refers(UnitdataCallback)
}

type enumerated MSC_State {
	MSC_STATE_NONE,
	MSC_STATE_WAIT_ASS_COMPL,
	MSC_STATE_WAIT_CRCX_ACK,
	MSC_STATE_WAIT_MDCX_ACK,
	MSC_STATE_WAIT_CLEAR_COMPL,
	MSC_STATE_WAIT_DLCX_ACK
}

/* register an expect with the BSSMAP core */
private function f_create_exp(octetstring l3_enc) runs on MSC_ConnHdlr {
	BSSMAPEM.call(BSSMAPEM_register:{l3_enc, self}) {
		[] BSSMAPEM.getreply(BSSMAPEM_register:{?, ?}) {};
	}
}

type record TestHdlrParams {
	OCT1		ra,
	GsmFrameNumber	fn,
	hexstring	imsi,
	RslLinkId	link_id
};

template (value) TestHdlrParams t_def_TestHdlrPars := {
	ra := '23'O,
	fn := 23,
	imsi := '001019876543210'H,
	link_id := valueof(ts_RslLinkID_DCCH(0))
}

function f_create_chan_and_exp(TestHdlrParams pars) runs on MSC_ConnHdlr {
	var MobileIdentityLV mi := valueof(ts_MI_IMSI_LV(pars.imsi));
	var PDU_ML3_MS_NW l3_info := valueof(ts_CM_SERV_REQ('0001'B, mi));
	var octetstring l3_enc := enc_PDU_ML3_MS_NW(l3_info);

	/* call helper function for CHAN_RQD -> IMM ASS ->EST_IND */
	RSL_Emulation.f_chan_est(pars.ra, l3_enc, pars.link_id, pars.fn);
	f_create_exp(l3_enc);
}

function f_rsl_reply(template PDU_ML3_MS_NW l3, RSL_Message orig) runs on MSC_ConnHdlr {
	var RslChannelNr chan_nr := orig.ies[0].body.chan_nr;
	var RslLinkId link_id;
	if (orig.msg_type == RSL_MT_ENCR_CMD) {
		link_id := orig.ies[2].body.link_id;
	} else {
		link_id := orig.ies[1].body.link_id;
	}
	RSL.send(ts_RSL_DATA_IND(chan_nr, link_id, enc_PDU_ML3_MS_NW(valueof(l3))));
}

function f_cipher_mode(OCT1 alg, OCT8 key, template OCT16 kc128 := omit) runs on MSC_ConnHdlr {
	var PDU_BSSAP bssap;
	var RSL_Message rsl;

	if (isvalue(kc128)) {
		BSSAP.send(ts_BSSMAP_CipherModeCmdKc128(alg, key, valueof(kc128)));
	} else {
		BSSAP.send(ts_BSSMAP_CipherModeCmd(alg, key));
	}
	alt {
	/* RSL/UE Side */
	[] RSL.receive(tr_RSL_ENCR_CMD(g_chan_nr, ?, alg, key)) -> value rsl {
		var PDU_ML3_NW_MS l3 := dec_PDU_ML3_NW_MS(rsl.ies[3].body.l3_info.payload);
		log("Rx L3 from net: ", l3);
		if (ischosen(l3.msgs.rrm.cipheringModeCommand)) {
			f_rsl_reply(ts_RRM_CiphModeCompl, rsl);
		}
		repeat;
		}
	[] BSSAP.receive(tr_BSSMAP_CipherModeCompl) -> value bssap {
		// bssap.bssmap.cipherModeComplete.chosenEncryptionAlgorithm.algoritmhIdentifier
		setverdict(pass);
		}
	[] BSSAP.receive(tr_BSSMAP_CipherModeRej) -> value bssap {
		setverdict(fail, "Ciphering Mode Reject");
		}
	}
}

/* establish a channel fully, expecting an assignment matching 'exp' */
function f_establish_fully(TestHdlrParams pars, PDU_BSSAP ass_cmd, template PDU_BSSAP exp_ass_cpl)
runs on MSC_ConnHdlr return PDU_BSSAP {
	var PDU_BSSAP bssap;
	var RSL_Message rsl;
	timer T := 10.0;
	var boolean exp_compl := ischosen(exp_ass_cpl.pdu.bssmap.assignmentComplete);
	var boolean crcx_seen := false;
	var boolean rr_modify_seen := false;

	f_create_chan_and_exp(pars);
	/* we should now have a COMPL_L3 at the MSC */

	BSSAP.receive(tr_BSSMAP_ComplL3);
	BSSAP.send(ass_cmd);
	alt {
	/* if we receive exactly what we expected, always return + pass */
	[] BSSAP.receive(exp_ass_cpl) -> value bssap {
		setverdict(pass);
		return bssap;
		}
	[rr_modify_seen == false] RSL.receive(tr_RSL_DATA_REQ(g_chan_nr)) -> value rsl {
		var PDU_ML3_NW_MS l3 := dec_PDU_ML3_NW_MS(rsl.ies[2].body.l3_info.payload);
		log("Rx L3 from net: ", l3);
		if (ischosen(l3.msgs.rrm.channelModeModify)) {
			f_rsl_reply(ts_RRM_ModeModifyAck(l3.msgs.rrm.channelModeModify.channelDescription,
							 l3.msgs.rrm.channelModeModify.channelMode), rsl);
			rr_modify_seen := true;
		}
		repeat;
		}
	[rr_modify_seen] RSL.receive(tr_RSL_MsgTypeD(RSL_MT_MODE_MODIFY_REQ)) -> value rsl {
		RSL.send(ts_RSL_MODE_MODIFY_ACK(g_chan_nr));
		repeat;
		}
	[crcx_seen == false] RSL.receive(tr_RSL_IPA_CRCX(g_chan_nr)) -> value rsl {
		RSL.send(ts_RSL_IPA_CRCX_ACK(g_chan_nr, 1, 1, 1, 1));
		crcx_seen := true;
		repeat;
		}
	[crcx_seen] RSL.receive(tr_RSL_IPA_MDCX(g_chan_nr, ?)) -> value rsl{
		RSL.send(ts_RSL_IPA_MDCX_ACK(g_chan_nr, 1, 1, 1, 1));
		repeat;
		}
	[exp_compl] BSSAP.receive(tr_BSSMAP_AssignmentComplete) {
		setverdict(fail, "Received non-matching ASSIGNMENT COMPLETE");
		}
	[exp_compl] BSSAP.receive(tr_BSSMAP_AssignmentFail) {
		setverdict(fail, "Received unexpected ASSIGNMENT FAIL");
		}
	[not exp_compl] BSSAP.receive(tr_BSSMAP_AssignmentComplete) {
		setverdict(fail, "Received unexpected ASSIGNMENT COMPLETE");
		}
	[not exp_compl] BSSAP.receive(tr_BSSMAP_AssignmentFail) {
		setverdict(fail, "Received non-matching ASSIGNMENT FAIL");
		}
	[] T.timeout {
		setverdict(inconc, "Timeout waiting for ASSIGNMENT COMPLETE");
		}
	}

	self.stop;
}


}