module GTPv2_Templates {

/* (C) 2019 by Harald Welte <laforge@gnumonks.org>
 * 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 GTPv2_Types all;

private function fs_GTP2C_t_bit(template (omit) OCT4 teid) return BIT1 {
	if (istemplatekind(teid, "omit")) {
		return '0'B;
	} else {
		return '1'B;
	}
}

private function fs_GTP2C_p_bit(template (omit) PDU_GTPCv2 piggyback) return BIT1 {
	if (istemplatekind(piggyback, "omit")) {
		return '0'B;
	} else {
		return '1'B;
	}
}

template (present) PDU_GTPCv2 tr_PDU_GTP2C(template OCT4 teid := ?,
					   template (present) GTPCv2_PDUs pdus := ?,
					   template PDU_GTPCv2 piggyback := omit) := {
	spare := '000'B,
	t_Bit := ?,
	p_Bit := ?,
	version := '010'B,
	messageType := ?,
	lengthf := ?,
	tEID := teid,
	sequenceNumber := ?,
	spare3 := '00'O,
	gtpcv2_pdu := pdus,
	piggybackPDU_GTPCv2 := piggyback
}


/* 8.3 */
template (value) IMSI ts_GTP2C_Imsi(template (value) hexstring imsi) := {
	elementIdentifier := '01'O,
	lengthIndicator := 0, /* overwritten */
	instance := '0000'B,
	spare := '0000'B,
	iMSI_Value := imsi
}
template (present) IMSI tr_GTP2C_Imsi(template (present) hexstring imsi) := {
	elementIdentifier := '01'O,
	lengthIndicator := ?,
	instance := ?,
	spare := '0000'B,
	iMSI_Value := imsi
}

/* 8.4-1 */
/*
type enumerated GTP2C_Cause {
	Local_Detach 				(2),
	Complete_Detach				(3),
	RAT_changed_from_3GPP_to_Non_3GPP	(4),
	ISR_deactivation			(5),
	Error_Ind_from_RNC_eNB_SGSN_MME		(5),
	IMSI_Detach_Only			(7),
	Reactivation_Required			(8),
}
*/

const integer c_GTP2C_Cause_LocalDetach := 1;

/* 8.4 */
template (value) Cause ts_GTP2C_Cause(template (value) OCT1 cause,
				      template (value) BIT1 cs) := {
	elementIdentifier := '02'O,
	lengthIndicator := 0, /* overwritten */
	instance := '0000'B,
	spare := '0000'B,
	causeValue := cause,
	cS := cs,
	bCE := '0'B,
	pCE := '0'B,
	spare2 := '00000'B,
	typeOfOffendingIE := omit,
	lengthIndicator2 := omit,
	instanceOfOffendingIE := omit,
	spare3 := omit
}
template (present) Cause tr_GTP2C_Cause(template (present) OCT1 cause) := {
	elementIdentifier := '02'O,
	lengthIndicator := ?,
	instance := ?,
	spare := '0000'B,
	causeValue := cause,
	cS := ?,
	bCE := ?,
	pCE := ?,
	spare2 := '00000'B,
	typeOfOffendingIE := *,
	lengthIndicator2 := *,
	instanceOfOffendingIE := *,
	spare3 := *
}

/* 8.5 */
template (value) AccessPointName ts_GTP2C_APN(template (value) octetstring apn) := {
	elementIdentifier := '48'O,
	lengthIndicator := 0, /* overwritten */
	instance := '0000'B,
	spare := '0000'B,
	aPN_Value := apn
}
template (present) AccessPointName tr_GTP2C_APN(template (present) octetstring apn) := {
	elementIdentifier := '48'O,
	lengthIndicator := ?,
	instance := ?,
	spare := '0000'B,
	aPN_Value := apn
}

/* 8.14 */
template (value) PDN_AddressAllocation
ts_GTP2C_PdnAddrAlloc(template (value) BIT3 pdn_type,
		      template (value) PDN_Address_and_Prefix addr_pfx) := {
	elementIdentifier := '4F'O,
	lengthIndicator := 0, /* overwritten */
	instance := '0000'B,
	spare := '0000'B,
	pDN_Type := pdn_type,
	spare2 := '00000'B,
	pDN_Address_and_Prefix := addr_pfx
}
template (present) PDN_AddressAllocation
tr_GTP2C_PdnAddrAlloc(template (present) BIT3 pdn_type,
		      template (present) PDN_Address_and_Prefix addr_pfx) := {
	elementIdentifier := '4F'O,
	lengthIndicator := ?,
	instance := ?,
	spare := '0000'B,
	pDN_Type := pdn_type,
	spare2 := '00000'B,
	pDN_Address_and_Prefix := addr_pfx
}
template (value) PDN_AddressAllocation
ts_GTP2C_PdnAddrAlloc_v4(template (value) OCT4 addr) :=
	ts_GTP2C_PdnAddrAlloc('001'B, {iPv4_Address:=addr});
template (present) PDN_AddressAllocation
tr_GTP2C_PdnAddrAlloc_v4(template (present) OCT4 addr) :=
	ts_GTP2C_PdnAddrAlloc('001'B, {iPv4_Address:=addr});

/* 8.17 */
template (value) RAT_Type ts_GTP2C_RatType(template (value) integer rat) := {
	elementIdentifier := '53'O,
	lengthIndicator := 0, /* overwritten */
	instance := '0000'B,
	spare := '0000'B,
	rAT_TypeValue := rat,
	additionalOctets := omit
}
template (present) RAT_Type tr_GTP2C_RatType(template (present) integer rat) := {
	elementIdentifier := '53'O,
	lengthIndicator := ?,
	instance := ?,
	spare := '0000'B,
	rAT_TypeValue := rat,
	additionalOctets := *
}


/* 8.22 */
private function f_bit4oct(template (omit) octetstring os) return BIT1
{
	if (istemplatekind(os, "omit")) {
		return '0'B;
	} else {
		return '1'B;
	}
}
template (value) FullyQualifiedTEID
ts_GTP2C_FTEID(integer if_type, OCT4 teid, template (omit) OCT4 v4_addr := omit,
		template (omit) OCT16 v6_addr := omit) := {
	elementIdentifier := '57'O,
	lengthIndicator := 0, /* overwritten */
	instance := '0000'B,
	spare := '0000'B,
	interfaceType := if_type,
	v6_Flag := f_bit4oct(v4_addr),
	v4_Flag := f_bit4oct(v6_addr),
	tEID_GRE_Key := teid,
	iPv4_Address := v4_addr,
	iPv6_Address := v6_addr,
	additionalOctets := omit
}
template (present) FullyQualifiedTEID
tr_GTP2C_FTEID(template (present) integer if_type, template (present) OCT4 teid,
		template OCT4 v4_addr := omit,
		template OCT16 v6_addr := omit) := {
	elementIdentifier := '57'O,
	lengthIndicator := ?,
	instance := ?,
	spare := '0000'B,
	interfaceType := if_type,
	v6_Flag := ?,
	v4_Flag := ?,
	tEID_GRE_Key := teid,
	iPv4_Address := v4_addr,
	iPv6_Address := v6_addr,
	additionalOctets := omit
}


template (value) PDU_GTPCv2 ts_PDU_GTP2C(template (omit) OCT4 teid, template (value) OCT3 seq,
					 template (value) OCT1 msg_type,
					 template (value) GTPCv2_PDUs pdus,
					 template (omit) PDU_GTPCv2 piggyback := omit) := {
	spare := '000'B,
	t_Bit := fs_GTP2C_t_bit(teid),
	p_Bit := fs_GTP2C_p_bit(piggyback),
	version := '010'B,
	messageType := msg_type,
	lengthf := 0, /* overwritten */
	tEID := teid,
	sequenceNumber := seq,
	spare3 := '00'O,
	gtpcv2_pdu := pdus,
	piggybackPDU_GTPCv2 := piggyback
}


template (present) PDU_GTPCv2
tr_GTP2C_CreateSessionReq(template (present) hexstring imsi) := tr_PDU_GTP2C('00000000'O, {
	createSessionRequest := {
		iMSI := tr_GTP2C_Imsi(imsi),
		mSISDN := *,
		mEI := *,
		userLocationInfo := ?,
		servingNetwork := ?,
		rAT_Type := tr_GTP2C_RatType(6),
		indication := *,
		fullyQualifiedTEID := ?,
		accessPointName := tr_GTP2C_APN('012a'O), // '*'
		selectionMode := ?,
		pDN_Type := ?,
		pDN_AddressAllocation := ?,
		maxAPN_Restriction := ?,
		ambr := *,
		linkedEPS_Bearer_ID := omit,
		trustedWLANModeIndication := omit,
		protocolConfigOptions := omit,
		bearerContextGrouped := ?,
		traceInformation := *,
		recovery := omit,
		csid := omit,
		uE_TimeZone := ?,
		user_CSG_Information := omit,
		chargingCharacteristics := ?,
		lDN := omit,
		signallingPriorityIndication := *,
		iP_Addr := omit,
		portNumber := omit,
		aPCO := omit,
		trustedWLANAccessNetworkIdentifier := omit,
		cNOperatorSelectionEntity := omit,
		presenceReportingAreaInformation := omit,
		overloadControlInformationGrouped := omit,
		originationTimeStamp := *,
		maximumWaitTime := *,
		wLANLocationTimestamp := omit,
		nBIFOMContainer := omit,
		remoteUEContextGrouped := *,
		nodeIdentifier := *,
		extendedProtocolConfigOptions := omit,
		servingPLMNRateControl := omit,
		counter := omit,
		privateExtension := omit
	}});

template (value) PDU_GTPCv2
ts_GTP2C_CreateSessionResp(template (value) FullyQualifiedTEID_List fteids,
			   template (value) PDN_AddressAllocation addr) :=
ts_PDU_GTP2C('00000000'O, '000000'O, '20'O, {
	createSessionResponse := {
		cause := ts_GTP2C_Cause(int2oct(16, 1), '0'B),
		changeReportingAction := omit,
		cSG_InformationReportingAction := omit,
		heNBInformationReporting := omit,
		fullyQualifiedTEID := fteids,
		pDN_AddressAllocation := addr,
		aPN_Restriction := omit,
		ambr := omit,
		linkedEPS_Bearer_ID := omit,
		protocolConfigOptions := omit,
		bearerContextGrouped := omit,
		recovery := omit,
		chargingGatewayName := omit,
		chargingGatewayAddress := omit,
		csid := omit,
		lDN := omit,
		pGW_Back_OffTime := omit,
		aPCO := omit,
		trustedWLANIPv4Parameters := omit,
		indicationFlags := omit,
		presenceReportingAreaAction := omit,
		loadControlInformationGrouped := omit,
		overloadControlInformationGrouped := omit,
		nBIFOMContainer := omit,
		pDNConnectionChargingID := omit,
		extendedProtocolConfigOptions := omit,
		privateExtension := omit
	}});


}