module LLC_Types {
	import from General_Types all;
	import from Osmocom_Types all;

	/* TS 44.064 Chapter 6.2 */
	type record LlcAddressField {
		BIT1 pd ('0'B),
		boolean c_r,
		BIT2 reserved,
		LlcSapi sapi
	} with {
		variant (c_r) "FIELDLENGTH(1)"
	};

	template LlcAddressField t_LLC_Addr(template boolean c_r, template LlcSapi sapi) := {
		pd := '0'B,
		c_r := c_r,
		reserved := '00'B,
		sapi := sapi
	};

	const boolean LLC_CR_DL_CMD := true;
	const boolean LLC_CR_DL_RSP := false;
	const boolean LLC_CR_UL_CMD := false;
	const boolean LLC_CR_UL_RSP := true;

	template LlcAddressField t_LLC_Addr_DlCmd(template LlcSapi sapi) := t_LLC_Addr(true, sapi);
	template LlcAddressField t_LLC_Addr_DlRsp(template LlcSapi sapi) := t_LLC_Addr(false, sapi);
	template LlcAddressField t_LLC_Addr_UlCmd(template LlcSapi sapi) := t_LLC_Addr(false, sapi);
	template LlcAddressField t_LLC_Addr_UlRsp(template LlcSapi sapi) := t_LLC_Addr(true, sapi);

	type enumerated LlcSapi {
		LLC_SAPI_RESERVED_0	('0000'B),
		LLC_SAPI_GMM		('0001'B),
		LLC_SAPI_TOM2		('0010'B),
		LLC_SAPI_LL3		('0011'B),
		LLC_SAPI_RESERVED_4	('0100'B),
		LLC_SAPI_LL5		('0101'B),
		LLC_SAPI_RESERVED_6	('0110'B),
		LLC_SAPI_SMS		('0111'B),
		LLC_SAPI_TOM8		('1000'B),
		LLC_SAPI_LL9		('1001'B),
		LLC_SAPI_RESERVED_10	('1010'B),
		LLC_SAPI_LL11		('1011'B),
		LLC_SAPI_RESERVED_12	('1100'B),
		LLC_SAPI_RESERVED_13	('1101'B),
		LLC_SAPI_RESERVED_14	('1110'B),
		LLC_SAPI_RESERVED_15	('1111'B)
	} with { variant "FIELDLENGTH(4)" };

	/* TS 44.064 Chapter 6.3 */
	type record LlcCtrlFieldI {
		BIT1 presence ('0'B),
		boolean a,
		BIT1 spare,
		uint9_t n_s,
		BIT1 spare2,
		uint9_t n_r,
		LlcCtrlS s
	} with { variant
		(a) "FIELDLENGTH(1)"
	};

	/* TS 44.064 Chapter 6.3 */
	type record LlcCtrlFieldS {
		BIT2 presence ('10'B),
		boolean a,
		BIT2 spare,
		uint9_t  n_r,
		LlcCtrlS s
	} with {
		variant (a) "FIELDLENGTH(1)"
	};

	/* TS 44.064 Chapter 6.3 */
	type record LlcCtrlFieldUI {
		BIT3 presence ('110'B),
		BIT2 spare,
		uint9_t n_u,
		boolean e,
		boolean pm
	} with {
		variant (e) "FIELDLENGTH(1)"
		variant (pm) "FIELDLENGTH(1)"
	};

	template LlcCtrlFieldUI t_LlcCtrlUI(template uint8_t n_u) := {
		presence := '110'B,
		spare := '00'B,
		n_u := n_u,
		e := false,
		pm := true
	};

	/* TS 44.064 Chapter 6.3 */
	type record LlcCtrlFieldU {
		BIT3 presence ('111'B),
		boolean p_f,
		LlcCtrlM m
	} with {
		variant (p_f) "FIELDLENGTH(1)"
	};


	/* TS 44.064 Chapter 6.4 */
	type enumerated LlcCtrlS {
		LLC_S_RR	('00'B),
		LLC_S_ACK	('01'B),
		LLC_S_RNR	('10'B),
		LLC_S_SACK	('11'B)
	} with { variant "FIELDLENGTH(2)" };

	/* TS 44.064 Chapter 6.4 */
	type enumerated LlcCtrlM {
		LLC_M_DM	('0001'B),
		LLC_M_DISC	('0100'B),
		LLC_M_UA	('0110'B),
		LLC_M_SABM	('0111'B),
		LLC_M_FRMR	('1000'B),
		LLC_M_XID	('1011'B),
		LLC_M_NULL	('0000'B)
	} with { variant "FIELDLENGTH(4)" };

	type union LlcCtrlUnion {
		LlcCtrlFieldI	i,
		LlcCtrlFieldS	s,
		LlcCtrlFieldUI	ui,
		LlcCtrlFieldU	u
	} with { variant "TAG(i, presence = '0'B;
			      s, presence = '10'B;
			      ui, presence = '110'B;
			      u, presence = '111'B)"
		 variant "FIELDORDER(msb)"
	};

	external function enc_LlcCtrlUnion(in LlcCtrlUnion pdu) return octetstring
		with { extension "prototype(convert) encode(RAW)" };
	external function dec_LlcCtrlUnion(in octetstring stream) return LlcCtrlUnion
		with { extension "prototype(convert) decode(RAW)" };


	type uint24_t LlcFcs;

	type record LlcPdu {
		LlcAddressField	addr,
		LlcCtrlUnion	ctrl,
		octetstring	payload//,
		//LlcFcs		fcs
	} with { variant "" };

	external function enc_LlcPdu(in LlcPdu pdu) return octetstring
		with { extension "prototype(convert) encode(RAW)" };
	external function dec_LlcPdu(in octetstring stream) return LlcPdu
		with { extension "prototype(convert) decode(RAW)" };


	template LlcPdu t_LLC_UI(template boolean c_r, template uint8_t n_u, template octetstring payload,
				 template LlcSapi sapi := LLC_SAPI_GMM) := {
		addr := t_LLC_Addr(c_r, sapi),
		ctrl := {
			ui := t_LlcCtrlUI(n_u)
		},
		payload := payload
	};
} with { encode "RAW"; variant "FIELDORDER(msb)" }