/* Encoding/Decoding routines for GSM System Information messages
 * according to 3GPP TS 44.018 Version 12.3.0 Release 12 */

/* (C) 2017 by Harald Welte <laforge@gnumonks.org> */

module GSM_Types {

	import from General_Types all;
	import from Osmocom_Types all;

	type integer GsmArfcn (0..1023);
	type integer UmtsArfcn (0..16383);
	type integer UmtsScramblingCode (0..511);
	const integer GsmMaxFrameNumber := 26*51*2048;
	type integer GsmFrameNumber (0..GsmMaxFrameNumber);
	type integer GsmRxLev (0..63);
	type integer GsmTsc (0..7) with { variant "FIELDLENGTH(8)" };
	type uint32_t GsmTmsi;
	type uint32_t GprsTlli;

	/* Table 10.4.1 of Section 10.4 / 3GPP TS 44.018 */
	type enumerated RrMessageType {
		ADDITIONAL_ASSIGNMENT		('00111011'B),
		IMMEDIATE_ASSIGNMENT		('00111111'B),
		IMMEDIATE_ASSIGNMENT_EXTENDED	('00111001'B),
		IMMEDIATE_ASSIGNMENT_REJECT	('00111010'B),
		IMMEDIATE_PACKET_ASSIGNMENT	('01101001'B),

		CIPHERING_MODE_COMMAND		('00110101'B),
		CIPHERING_MODE_COMPLETE		('00110010'B),

		CONFIGURATION_CHANGE_COMMAND	('00110000'B),
		CONFIGURATION_CHANGE_ACK	('00110001'B),
		CONFIGURATION_CHANGE_REJECT	('00110011'B),

		ASSIGNMENT_COMMAND		('00101110'B),
		ASSIGNMENT_COMPLETE		('00101001'B),
		ASSIGNMENT_FAILURE		('00101111'B),
		HANDOVER_COMMAND		('00101011'B),
		HANDOVER_COMPLETE		('00101100'B),
		HANDOVER_FAILURE		('00101000'B),
		PHYSICAL_INFORMATION		('00101101'B),

		CHANNEL_RELEASE			('00001101'B),
		PARTIAL_RELEASE			('00001010'B),
		PARTIAL_RELEASE_COMPLETE	('00001111'B),

		PAGING_REQUEST_TYPE_1		('00100001'B),
		PAGING_REQUEST_TYPE_2		('00100010'B),
		PAGING_REQUEST_TYPE_3		('00100100'B),
		PAGING_RESPONSE			('00100111'B),
		NOTIFICATION_NCH		('00100000'B),
		NOTIFICATION_RESPOSNE		('00100110'B),

		SYSTEM_INFORMATION_TYPE_8	('00011000'B),
		SYSTEM_INFORMATION_TYPE_1	('00011001'B),
		SYSTEM_INFORMATION_TYPE_2	('00011010'B),
		SYSTEM_INFORMATION_TYPE_3	('00011011'B),
		SYSTEM_INFORMATION_TYPE_4	('00011100'B),
		SYSTEM_INFORMATION_TYPE_5	('00011101'B),
		SYSTEM_INFORMATION_TYPE_6	('00011110'B),
		SYSTEM_INFORMATION_TYPE_7	('00011111'B),
		SYSTEM_INFORMATION_TYPE_2bis	('00000010'B),
		SYSTEM_INFORMATION_TYPE_2ter	('00000011'B),
		SYSTEM_INFORMATION_TYPE_2quater	('00000111'B),
		SYSTEM_INFORMATION_TYPE_5bis	('00000101'B),
		SYSTEM_INFORMATION_TYPE_5ter	('00000110'B),
		SYSTEM_INFORMATION_TYPE_9	('00000100'B),
		SYSTEM_INFORMATION_TYPE_13	('00000000'B),

		SYSTEM_INFORMATION_TYPE_16	('00111101'B),
		SYSTEM_INFORMATION_TYPE_17	('00111110'B),

		CHANNEL_MODE_MODIFY		('00010000'B),
		RR_STATUS			('00010010'B),
		CHANNEL_MODE_MODIFY_ACKNOWLEDGE	('00010111'B),
		FREQUENCY_REDEFINITION		('00010100'B),
		MEASUREMENT_REPORT		('00010101'B),
		CLASSMARK_CHANGE		('00010110'B),
		CLASSMARK_ENQUIRY		('00010011'B),
		EXTENDED_MEASUREMENT_REPORT	('00110110'B),
		EXTENDED_MEASUREMENT_ORDER	('00110111'B),
		GPRS_SUSPENSION_REQUEST		('00110100'B),
		//MBMS_ANNOUNCEMENT		('00010110'B), duplicate?
		//SERVICE_INFORMATION		('00110110'B), duplicate?

		APPLICATION_INFORMATION		('00111000'B),

		SYSTEM_INFORMATION_TYPE_14	('00000001'B),
		SYSTEM_INFORMATION_TYPE_15	('01000011'B),
		SYSTEM_INFORMATION_TYPE_18	('01000000'B),
		SYSTEM_INFORMATION_TYPE_19	('01000001'B),
		SYSTEM_INFORMATION_TYPE_20	('01000010'B),
		SYSTEM_INFORMATION_TYPE_13alt	('01000100'B),
		SYSTEM_INFORMATION_TYPE_2n	('01000101'B),
		SYSTEM_INFORMATION_TYPE_21	('01000110'B),
		SYSTEM_INFORMATION_TYPE_22	('01000111'B),
		SYSTEM_INFORMATION_TYPE_23	('01001111'B),

		DTM_ASSIGNMENT_FAILURE		('01001000'B),
		DTM_REJECT			('01001001'B),
		DTM_REQUEST			('01001010'B),
		PACKET_ASSIGNMENT		('01001011'B),
		DTM_ASSIGNMENT_COMMAND		('01001100'B),
		DTM_INFORMATION			('01001101'B),
		PACKET_INFORMATION		('01001110'B),

		UTRAN_CLASSMARK_CHANGE		('01100000'B),
		CDMA2000_CLASSMARK_CHANGE	('01100010'B),
		INTERSYS_TO_UTRAN_HO_CMD	('01100011'B),
		INTERSYS_TO_CDMA2000_HO_CMD	('01100100'B),
		GERAN_IU_MODE_CLASSMARK_CHG	('01100101'B),
		INTERSYS_TO_EUTRAN_HO_CMD	('01100110'B)
	} with { variant "FIELDLENGTH(8)" };

	type octetstring RestOctets  with { variant "PADDING(yes), PADDING_PATTERN('00101011'B)" };
	type hexstring GsmBcdString with { variant "HEXORDER(low)" };
	type GsmBcdString BcdMccMnc with { variant "FIELDLENGTH(6)" };

	type record L2PseudoLength {
		uint6_t		l2_plen,
		BIT2		zero_one
	} with { variant "" };

	template L2PseudoLength t_L2Pseudolength(template uint6_t len) := {
		l2_plen := len,
		zero_one := '01'B
	};

	type record RrHeader {
		L2PseudoLength	l2_plen,
		uint4_t		skip_indicator,
		uint4_t		rr_protocol_discriminator,
		RrMessageType	message_type
	} with { variant "" };

	template RrHeader t_RrHeader(RrMessageType msg_type, template uint6_t len) := {
		l2_plen := t_L2Pseudolength(len),
		skip_indicator := 0,
		rr_protocol_discriminator := 6,
		message_type := msg_type
	};

	type record RrL3Header {
		uint4_t		skip_indicator,
		uint4_t		rr_protocol_discriminator,
		RrMessageType	message_type
	} with { variant "" };

	type record MaioHsn {
	} with { variant "" };

	/* TS 24.008 10.5.1.1 */
	type uint16_t CellIdentity;

	/* TS 24.008 10.5.1.2 */
	type uint4_t CipheringKeySeqNr (0..7);

	/* 24.008 10.5.1.3 */
	type record LocationAreaIdentification {
		BcdMccMnc	mcc_mnc,
		uint16_t	lac
	} with { variant "" };

	/* TS 24.008 10.5.1.4 */
	type enumerated MobileIdentityType {
		MI_TYPE_NONE	(0),
		MI_TYPE_IMSI,
		MI_TYPE_IMEI,
		MI_TYPE_IMEISV,
		MI_TYPE_TMSI,
		MI_TYPE_TMGI
	} with { variant "FIELDLENGTH(3)" };

	type record MobileIdentityBCD {
		MobileIdentityType	mi_type (MI_TYPE_IMSI, MI_TYPE_IMEI, MI_TYPE_IMEISV),
		boolean			odd,
		hexstring		digits
	} with { variant "" };

	type record MobileIdentityTMSI {
		BIT4			pad ('1111'B),
		boolean			odd (false),
		MobileIdentityType	mi_type (MI_TYPE_TMSI),
		GsmTmsi			tmsi
	} with { variant "" };

	type record MobileIdentityNone {
		BIT4			pad ('1111'B),
		boolean			odd (false),
		MobileIdentityType	mi_type (MI_TYPE_NONE)
	} with { variant "" };

	type union MobileIdentity {
		MobileIdentityBCD	bcd,
		MobileIdentityTMSI	tmsi,
		MobileIdentityNone	unused
	} with { variant "TAG(bcd, mi_type = MI_TYPE_IMSI;
			      bcd, mi_type = MI_TYPE_IMEI;
			      bcd, mi_type = MI_TYPE_IMEISV;
			      tmsi, mi_type = MI_TYPE_TMSI;
			      unused, mi_type = MI_TYPE_NONE)" };

	type record MobileIdentityLV {
		uint8_t		len,
		MobileIdentity	mi
	} with { variant (len) "LENGTHTO(mi)" };

	type record MobileIdentityTLV {
		uint8_t		tag,
		uint8_t		len,
		MobileIdentity	mi
	} with { variant (len) "LENGTHTO(mi)" };

	/* TS 24.008 10.5.1.5 */
	type record MsClassmark1 {
		BIT1		spare,
		uint2_t		rev_level,
		boolean		es_ind,
		boolean		a51,
		uint3_t		rf_pwr_cap
	} with { variant "" };

	/* TS 24.008 10.5.1.6 */
	type record MsClassmark2 {
		BIT1		spare,
		uint2_t		rev_level,
		boolean		es_ind,
		boolean		a51,
		uint3_t		rf_pwr_cap,
		BIT1		spare1,
		boolean		ps_cap,
		uint2_t		ss_screen_ind,
		boolean		sm_cap,
		boolean		vbs,
		boolean		vgcs,
		boolean		fc,
		boolean		cm3,
		BIT1		spare2,
		boolean		lcsva_cap,
		boolean		ucs2,
		boolean		solsa,
		boolean		cmsp,
		boolean		a53,
		boolean		a52
	} with { variant "" };
	type record MsClassmark2LV {
		uint8_t		len,
		MsClassmark2	cm2
	} with { variant (len) "LENGTHTO(cm2)" };


	/* 44.018 10.5.2.5 */
	type record ChannelDescription {
		RslChannelNr	chan_nr,
		uint3_t		tsc,
		boolean		h,
		uint12_t	arfcn optional,
		MaioHsn		maio_hsn optional
	} with { variant (arfcn) "PRESENCE(h = false)"
		 variant (maio_hsn) "PRESENCE(h = true)" };

	type record ChannelDescriptionTV {
		OCT1		iei,
		ChannelDescription v
	} with { variant "" };

	/* 10.5.2.8 */
	type enumerated ChannelNeeded {
		CHAN_NEED_ANY	(0),
		CHAN_NEED_SDCCH	(1),
		CHAN_NEED_TCH_F	(2),
		CHAN_NEED_TCH_H	(3)
	} with { variant "FIELDLENGTH(2)" };
	type record ChannelNeeded12 {
		ChannelNeeded	second,
		ChannelNeeded	first
	} with { variant "" };

	/* 10.5.2.21 */
	type record MobileAllocation {
		uint8_t 	len,
		bitstring	ma
	} with { variant (len) "LENGTHTO(ma)" };

	/* 10.5.2.25a */
	type OCT3 PacketChannelDescription;

	/* 10.5.2.25b */
	type record DedicatedModeOrTbf {
		BIT1	spare,
		boolean	tma,
		boolean	downlink,
		boolean tbf
	} with { variant "" };

	/* 10.5.2.26 */
	type enumerated PageMode {
		PAGE_MODE_NORMAL,
		PAGE_MODE_EXTENDED,
		PAGE_MODE_REORGANIZATION,
		PAGE_MODE_SAME_AS_BEFORE
	} with { variant "FIELDLENGTH(4)" };

	/* 10.5.2.30 */
	type record RequestReference {
		bitstring	ra length(8),
		uint5_t 	t1p,
		uint6_t 	t3,
		uint5_t		t2
	} with { variant "" };

	template RequestReference t_RequestReference(template bitstring ra, template uint5_t t1p, template uint6_t t3, template uint5_t t2) := {
		ra := ra,
		t1p := t1p,
		t3 := t3,
		t2 := t2
	}

	/* compute the expected request reference for given RA + FN */
	function f_compute_ReqRef(uint8_t ra, GsmFrameNumber fn) return RequestReference {
		var RequestReference req_ref := { ra := int2bit(ra, 8) };
		req_ref.t1p := (fn / 1326) mod 32;
		req_ref.t2 := fn mod 26;
		req_ref.t3 := fn mod 51;
		return req_ref
	}

	/* 10.5.2.40 */
	type integer TimingAdvance (0..219);

	/* 10.5.2.43 */
	type uint8_t WaitIndication;

	/* 10.5.2.76 */
	type record FeatureIndicator {
		BIT2	spare,
		boolean	cs_ir,
		boolean	ps_ir
	} with { variant "" };

	/* 24.008 10.5.5.6 */
	type record DrxParameter {
		uint8_t		split_pg_cycle_code,
		uint4_t		drx_cycle_len_coeff,
		boolean		split_on_ccch,
		uint3_t		non_drx_timer
	} with { variant "" };

	/* 24.008 10.5.5.15 */
	type record RoutingAreaIdentification {
		LocationAreaIdentification	lai,
		uint8_t				rac
	} with { variant "" };


	/* 9.1.18 */
	type record ImmediateAssignment {
		DedicatedModeOrTbf		ded_or_tbf,
		PageMode			page_mode,
		ChannelDescription		chan_desc optional,
		PacketChannelDescription	pkt_chan_desc optional,
		RequestReference		req_ref,
		TimingAdvance			timing_advance,
		MobileAllocation		mobile_allocation
	} with { variant (chan_desc) "PRESENCE(ded_or_tbf.tbf = false)"
		 variant (pkt_chan_desc) "PRESENCE(ded_or_tbf.tbf = true)" };

	/* 9.1.20 */
	type record ReqRefWaitInd {
		RequestReference		req_ref,
		WaitIndication			wait_ind
	} with { variant "" };
	type record length(4) of ReqRefWaitInd ReqRefWaitInd4;
	type record ImmediateAssignmentReject {
		FeatureIndicator		feature_ind,
		PageMode			page_mode,
		ReqRefWaitInd4			payload
	} with { variant "" };

	/* 9.1.22 */
	type record PagingRequestType1 {
		ChannelNeeded12			chan_needed,
		PageMode			page_mode,
		MobileIdentityLV		mi1,
		MobileIdentityTLV		mi2 optional,
		RestOctets			rest_octets
	} with { variant "TAG(mi2, tag = 23)" };

	/* 9.1.23 */
	type record PagingRequestType2 {
		ChannelNeeded12			chan_needed,
		PageMode			page_mode,
		GsmTmsi				mi1,
		GsmTmsi				mi2,
		MobileIdentityTLV		mi3 optional,
		RestOctets			rest_octets
	} with { variant "TAG(mi3, tag = 23)" };

	/* 9.1.24 */
	type record length(4) of GsmTmsi GsmTmsi4;
	type record PagingRequestType3 {
		ChannelNeeded12			chan_needed,
		PageMode			page_mode,
		GsmTmsi4			mi,
		RestOctets			rest_octets
	} with { variant "" };


	type union RrUnion {
/*
		SystemInformationType1		si1,
		SystemInformationType2		si2,
		SystemInformationType2bis	si2bis,
		SystemInformationType2ter	si2ter,
		SystemInformationType3		si3,
		SystemInformationType4		si4,
		SystemInformationType5		si5,
		SystemInformationType5bis	si5bis,
		SystemInformationType5ter	si5ter,
		SystemInformationType6		si6,
*/
		ImmediateAssignment		imm_ass,
		ImmediateAssignmentReject	imm_ass_rej,
		PagingRequestType1		pag_req_1,
		PagingRequestType2		pag_req_2,
		PagingRequestType3		pag_req_3,
		octetstring			other
	} with { variant "" };

	/* Special RR Message on BCCH / CCCH Dowlink */

	type record GsmRrMessage {
		RrHeader	header,
		RrUnion		payload
	} with { variant (payload) "CROSSTAG(
/*
			      si1, header.message_type = SYSTEM_INFORMATION_TYPE_1;
			      si2, header.message_type = SYSTEM_INFORMATION_TYPE_2;
			      si2bis, header.message_type = SYSTEM_INFORMATION_TYPE_2bis;
			      si2ter, header.message_type = SYSTEM_INFORMATION_TYPE_2ter;
			      si3, header.message_type = SYSTEM_INFORMATION_TYPE_3;
			      si4, header.message_type = SYSTEM_INFORMATION_TYPE_4;
			      si5, header.message_type = SYSTEM_INFORMATION_TYPE_5;
			      si5bis, header.message_type = SYSTEM_INFORMATION_TYPE_5bis;
			      si5ter, header.message_type = SYSTEM_INFORMATION_TYPE_5ter;
			      si6, header.message_type = SYSTEM_INFORMATION_TYPE_6;
*/
				imm_ass, header.message_type = IMMEDIATE_ASSIGNMENT;
				imm_ass_rej, header.message_type = IMMEDIATE_ASSIGNMENT_REJECT;
				pag_req_1, header.message_type = PAGING_REQUEST_TYPE_1;
				pag_req_2, header.message_type = PAGING_REQUEST_TYPE_2;
				pag_req_3, header.message_type = PAGING_REQUEST_TYPE_3;
			      other, OTHERWISE;
			)" };

	external function enc_GsmRrMessage(in GsmRrMessage msg) return octetstring
		with { extension "prototype(convert) encode(RAW)" };
	external function dec_GsmRrMessage(in octetstring stream) return GsmRrMessage
		with { extension "prototype(convert) decode(RAW)" };

	/* Normal L3 Message on Dedicated Channel */

	/* 9.1.25 Paging Response */
	type record PagingResponse {
		uint4_t			spare_half_octet,
		CipheringKeySeqNr	cksn,
		MsClassmark2LV		cm2,
		MobileIdentityLV	mi,
		uint8_t			addl_upd_par optional
	} with { variant "" };

	type union RrL3Union {
		PagingResponse	paging_response,
		octetstring	other
	};

	type record GsmRrL3Message {
		RrL3Header	header,
		RrL3Union	payload
	} with { variant (payload) "CROSSTAG(
				paging_response, header.message_type = PAGING_RESPONSE;

				other, OTHERWISE;
		)" }

	/* TS 48.058 9.3.1 Channel Number IE */
	type enumerated RslChanNr0 {
		RSL_CHAN_NR_INVALID	('00'H),
		RSL_CHAN_NR_Bm_ACCH	('01'H),
		RSL_CHAN_NR_BCCH	('10'H),
		RSL_CHAN_NR_RACH	('11'H),
		RSL_CHAN_NR_PCH_AGCH	('12'H)
	} with { variant "FIELDLENGTH(5)" };

	type record RslChanNr2 {
		BIT4		tag ('0001'B),
		uint1_t		sub_chan
	} with { variant "FIELDLENGTH(5)" };

	type record RslChanNr4 {
		BIT3		tag ('001'B),
		uint2_t		sub_chan
	} with { variant "FIELDLENGTH(5)" };

	type record RslChanNr8 {
		BIT2		tag ('01'B),
		uint3_t		sub_chan
	} with { variant "FIELDLENGTH(5)" };

	type union RslChanNrU {
		RslChanNr0	ch0,
		RslChanNr2	lm,
		RslChanNr4	sdcch4,
		RslChanNr8	sdcch8
	} with {
		variant "TAG(lm, tag = '0001'B;
			     sdcch4, tag = '001'B;
			     sdcch8, tag = '01'B;
			     ch0, OTHERWISE)"
		variant "FIELDLENGTH(5)"
	};

	type record RslChannelNr {
		RslChanNrU	u,
		uint3_t		tn
	} with { variant "FIELDLENGTH(8)" };

	template RslChannelNr t_RslChanNr0(template uint3_t tn, template RslChanNr0 cht) := {
		u := { ch0 := cht },
		tn := tn
	}

	template RslChannelNr t_RslChanNr_RACH(template uint3_t tn) := t_RslChanNr0(tn, RSL_CHAN_NR_RACH);
	template RslChannelNr t_RslChanNr_BCCH(template uint3_t tn) := t_RslChanNr0(tn, RSL_CHAN_NR_BCCH);
	template RslChannelNr t_RslChanNr_PCH_AGCH(template uint3_t tn) := t_RslChanNr0(tn, RSL_CHAN_NR_PCH_AGCH);
	template RslChannelNr t_RslChanNr_Bm(template uint3_t tn) := t_RslChanNr0(tn, RSL_CHAN_NR_Bm_ACCH);
	template RslChannelNr t_RslChanNr_Lm(template uint3_t tn, uint1_t sub_slot) := {
		u := { lm := { tag := '0001'B, sub_chan := sub_slot } },
		tn := tn
	}
	template RslChannelNr t_RslChanNr_SDCCH4(template uint3_t tn, template uint2_t sub_slot) := {
		u := { sdcch4 := { tag := '001'B, sub_chan := sub_slot } },
		tn := tn
	}
	template RslChannelNr t_RslChanNr_SDCCH8(template uint3_t tn, template uint3_t sub_slot) := {
		u := { sdcch8 := { tag := '01'B, sub_chan := sub_slot } },
		tn := tn
	}

	/* TS 48.058 9.3.2 Link ID */
	type enumerated RslLinkIdC {
		FACCH_SDCCH	(0),
		SACCH		(1)
	} with { variant "FIELDLENGTH(2)" };

	type enumerated RslSapi0Prio {
		SAPI0_PRIO_NORMAL	(0),
		SAPI0_PRIO_HIGH		(1),
		SAPI0_PRIO_LOW		(2)
	} with { variant "FIELDLENGTH(2)" };

	type uint3_t GsmSapi;

	type record RslLinkId {
		RslLinkIdC	c,
		boolean		na,
		RslSapi0Prio	prio,
		GsmSapi		sapi
	} with { variant "" };

	template RslLinkId tr_RslLinkId := {
		c := ?,
		na := ?,
		prio := ?,
		sapi := ?
	};

	template RslLinkId tr_RslLinkID_DCCH(template GsmSapi sapi) modifies tr_RslLinkId := {
		c := FACCH_SDCCH,
		na := false,
		sapi := sapi
	};

	template RslLinkId tr_RslLinkID_SACCH(template GsmSapi sapi) modifies tr_RslLinkId := {
		c := SACCH,
		na := false,
		sapi := sapi
	};

	template RslLinkId ts_RslLinkID_DCCH(GsmSapi sapi) := {
		c := FACCH_SDCCH,
		na := false,
		prio := SAPI0_PRIO_NORMAL,
		sapi := sapi
	};

	template RslLinkId ts_RslLinkID_SACCH(GsmSapi sapi) := {
		c := SACCH,
		na := false,
		prio := SAPI0_PRIO_NORMAL,
		sapi := sapi
	};

} with { encode "RAW"; variant "FIELDORDER(msb)" }