diff --git a/remsim/RSPRO.asn b/remsim/RSPRO.asn
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+----------------------------------------------------------------------
+-- RSPRO - Remote SIM Protocol, part of Osmocom Remote SIM Suite
+-- (C) 2018 by Harald Welte <laforge@gnumonks.org>
+-- All Rights Reserved
+--
+-- SPDX-License-Identifier: GPL-2.0+
+--
+-- This program is free software; you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation; either version 2 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License along
+-- with this program; if not, write to the Free Software Foundation, Inc.,
+-- 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+--
+----------------------------------------------------------------------
+
+RSPRO {} DEFINITIONS
+
+IMPLICIT TAGS
+
+::=
+
+BEGIN
+
+EXPORTS
+	RsproPDU
+;
+
+----------------------------------------------------------------------
+-- Elementary Data Types
+----------------------------------------------------------------------
+
+-- Some random ID the requestor can chose and which the client echos back in a response.
+-- This allows multiple outstanding commands in flight and matching of responses to requests.
+OperationTag ::= INTEGER(0..2147483647)
+
+-- Unique identifier of a given SIM bank
+BankId ::= INTEGER(0..1023)
+
+-- Unique identifier of a given client (modem)
+ClientId ::= INTEGER(0..1023)
+
+ComponentType ::= ENUMERATED {
+	-- client: Modems / Phones
+	remsimClient			(0),
+	-- server: Coordination
+	remsimServer			(1),
+	-- bank daemon: SIM cards
+	remsimBankd			(2)
+}
+ComponentName ::= IA5String (SIZE (1..32))
+ComponentIdentity ::= SEQUENCE {
+	type		ComponentType,
+	name		ComponentName,
+	software	[0] ComponentName,
+	swVersion	[1] ComponentName,
+	hwManufacturer	[2] ComponentName OPTIONAL,
+	hwModel		[3] ComponentName OPTIONAL,
+	hwSerialNr	[4] ComponentName OPTIONAL,
+	hwVersion	[5] ComponentName OPTIONAL,
+	fwVersion	[6] ComponentName OPTIONAL,
+	...
+}
+
+-- IP address / port details
+Ipv4Address ::= OCTET STRING (SIZE (4))
+Ipv6Address ::= OCTET STRING (SIZE (16))
+IpAddress ::= CHOICE {
+	ipv4	[0] Ipv4Address,
+	ipv6	[1] Ipv6Address
+}
+PortNumber ::= INTEGER (0..65535)
+IpPort ::= SEQUENCE {
+	ip	IpAddress,
+	port	PortNumber
+}
+
+-- Result of a given operation
+ResultCode ::= ENUMERATED {
+	ok				(0),
+	-- client / bank / slot ID not accepted
+	illegalClientId			(1),
+	illegalBankId			(2),
+	illegalSlotId			(3),
+	unsupportedProtocolVersion	(4),
+	unknownSlotmap			(5),
+
+	-- no card is present in given slot
+	cardNotPresent			(100),
+	-- card is present but unresponsive in given slot
+	cardUnresponsive		(101),
+	-- unrecoverable transmission errors detected
+	cardTransmissionError		(102),
+	...
+}
+
+ErrorCode ::= ENUMERATED {
+	-- Bankd or Server has received connection form unknown client (no mapping)
+	unknownClientConnected		(1),
+	-- unexpected disconnect (typically bankd reports client disconnect)
+	unexpectedDisconnect		(2),
+	unexpectedProtocolVersion	(3),
+	...
+}
+
+ErrorString ::= IA5String (SIZE (1..255))
+
+ErrorSeverity ::= ENUMERATED {
+	minor				(1),
+	major				(2),
+	fatal				(3),
+	...
+}
+
+-- Slot number within a SIM bank or a client.
+SlotNumber ::= INTEGER(0..1023)
+
+-- Slot identity on client (modem) side
+ClientSlot ::= SEQUENCE {
+	clientId	ClientId,
+	slotNr		SlotNumber,
+	...
+}
+
+-- Slot identity on SIM bank side
+BankSlot ::= SEQUENCE {
+	bankId		BankId,
+	slotNr		SlotNumber,
+	...
+}
+
+ATR ::= OCTET STRING (SIZE (1..55))
+
+-- flags related to a TPDU in either of the two directions
+TpduFlags ::= SEQUENCE {
+	-- indicates a TPDU header is present in this message
+	tpduHeaderPresent	BOOLEAN,
+	-- indicates last part of transmission in this direction
+	finalPart		BOOLEAN,
+	-- indicates a PB is present and we should continue with TX
+	procByteContinueTx	BOOLEAN,
+	-- indicates a PB is present and we should continue with RX
+	procByteContinueRx	BOOLEAN,
+	...
+}
+
+--- physical state of a given slot
+SlotPhysStatus ::= SEQUENCE {
+	-- is RST activated by the modem?
+	resetActive	[0] BOOLEAN,
+	-- is VCC applied by the modem?
+	vccPresent	[1] BOOLEAN OPTIONAL,
+	-- is CLK applied by the modem?
+	clkActive	[2] BOOLEAN OPTIONAL, -- not all hardware supports this
+	-- is card presence signalled to the modem?
+	cardPresent	[3] BOOLEAN OPTIONAL,
+	...
+}
+
+----------------------------------------------------------------------
+-- Messages
+----------------------------------------------------------------------
+
+
+-- BANKD->SERVER: SIM Bank connects to central server
+ConnectBankReq ::= SEQUENCE {
+	-- identity of the bank that is connecting to the server
+	identity	ComponentIdentity,
+	-- bank number, pre-configured on bank side
+	bankId		BankId,
+	numberOfSlots	SlotNumber,
+	-- IP/Port to which this bankd has bound and is listening for clients
+	bound		IpPort OPTIONAL,
+	...
+}
+ConnectBankRes ::= SEQUENCE {
+	-- identity of the server to which the bank is connecting
+	identity	ComponentIdentity,
+	result		ResultCode,
+	...
+}
+
+-- CLIENT->SERVER or CLIENT->BANKD
+ConnectClientReq ::= SEQUENCE {
+	-- identity of the client that is connecting to the server/bankd
+	identity	ComponentIdentity,
+	clientSlot	ClientSlot OPTIONAL, -- mandatory for CL->BANKD; CL->SERVER: old identity, if any
+	...
+}
+ConnectClientRes ::= SEQUENCE {
+	-- identity of the bankd/server to which the client is connecting
+	identity	ComponentIdentity,
+	result		ResultCode,
+	...
+}
+
+-- SERVER->BANKD: create a mapping between a given Bank:Slot <-> Client:Slot
+CreateMappingReq ::= SEQUENCE {
+	client		ClientSlot,
+	bank		BankSlot,
+	...
+}
+CreateMappingRes ::= SEQUENCE {
+	result		ResultCode,
+	...
+}
+
+-- SERVER->BANKD: remove a mapping between a given Bank:Slot <-> Client:Slot
+RemoveMappingReq ::= SEQUENCE {
+	client		ClientSlot,
+	bank		BankSlot,
+	...
+}
+RemoveMappingRes ::= SEQUENCE {
+	result		ResultCode,
+	...
+}
+
+-- SERVER->CLIENT: set Client ID
+ConfigClientIdReq ::= SEQUENCE {
+	-- server-allocated assignment of a client ID
+	clientSlot	ClientSlot,
+	...
+}
+ConfigClientIdRes ::= SEQUENCE {
+	result		ResultCode,
+	...
+}
+
+-- SERVER->CLIENT: set BankId/Slot and IP/Port
+ConfigClientBankReq ::= SEQUENCE {
+	-- server-allocated assignment of a client ID
+	bankSlot	BankSlot,
+	-- bank to which the client shall connect
+	bankd		IpPort,
+	...
+}
+ConfigClientBankRes ::= SEQUENCE {
+	result		ResultCode,
+	...
+}
+
+
+-- BANKD->CLIENT: configure the ATR which the card emulator (client) shall send to the modem
+SetAtrReq ::= SEQUENCE {
+	slot		ClientSlot,
+	atr		ATR,
+	...
+}
+SetAtrRes ::= SEQUENCE {
+	result		ResultCode,
+	...
+}
+
+-- CLIENT->BANKD: TPDU in Modem -> Card direction
+TpduModemToCard ::= SEQUENCE {
+	-- we include fully-qualified bank and client slots for easier debugging
+	fromClientSlot	ClientSlot,
+	toBankSlot	BankSlot,
+	flags		TpduFlags,
+	data		OCTET STRING,
+	...
+}
+
+-- BANKD->CLIENT: TPDU in Card -> Modem direction
+TpduCardToModem ::= SEQUENCE {
+	-- we include fully-qualified bank and client slots for easier debugging
+	fromBankSlot	BankSlot,
+	toClientSlot	ClientSlot,
+	flags		TpduFlags,
+	data		OCTET STRING,
+	...
+}
+
+-- CLIENT->BANKD: indciation about the current status of a client (modem side)
+ClientSlotStatusInd ::= SEQUENCE {
+	fromClientSlot	ClientSlot,
+	toBankSlot	BankSlot,
+	slotPhysStatus	SlotPhysStatus,
+	...
+}
+
+-- BANKD->CLIENT: indciation about the current status of a bank (modem side)
+BankSlotStatusInd ::= SEQUENCE {
+	fromBankSlot	BankSlot,
+	toClientSlot	ClientSlot,
+	slotPhysStatus	SlotPhysStatus,
+	...
+}
+
+-- *->SERVER: indication about some kind of error
+ErrorInd ::= SEQUENCE {
+	-- whoever is detecting + sending us the error
+	sender		ComponentType,
+	severity	ErrorSeverity,
+	code		ErrorCode,
+	-- any bank-side slot that's affected
+	bankSlot	[0] BankSlot OPTIONAL,
+	-- any client-side slot that's affected
+	clientSlot	[1] ClientSlot OPTIONAL,
+	-- any additional textual information
+	errorString	[2] ErrorString OPTIONAL,
+	...
+}
+
+
+----------------------------------------------------------------------
+-- PDU
+----------------------------------------------------------------------
+
+RsproPDUchoice ::= CHOICE {
+	-- configuration + management
+	connectBankReq		[0]	ConnectBankReq,
+	connectBankRes		[1]	ConnectBankRes,
+	connectClientReq	[2]	ConnectClientReq,
+	connectClientRes	[3]	ConnectClientRes,
+	createMappingReq	[4]	CreateMappingReq,
+	createMappingRes	[5]	CreateMappingRes,
+	removeMappingReq	[6]	RemoveMappingReq,
+	removeMappingRes	[7]	RemoveMappingRes,
+	configClientIdReq	[8]	ConfigClientIdReq,
+	configClientIdRes	[9]	ConfigClientIdRes,
+	configClientBankReq	[17]	ConfigClientBankReq,
+	configClientBankRes	[18]	ConfigClientBankRes,
+	errorInd		[16]	ErrorInd,
+	-- APDUs etc.
+	setAtrReq		[10]	SetAtrReq,
+	setAtrRes		[11]	SetAtrRes,
+	tpduModemToCard		[12]	TpduModemToCard,
+	tpduCardToModem		[13]	TpduCardToModem,
+	clientSlotStatusInd	[14]	ClientSlotStatusInd,
+	bankSlotStatusInd	[15]	BankSlotStatusInd,
+	...
+}
+
+RsproPDU ::= SEQUENCE {
+	version		[0] INTEGER(0..32),
+	tag		[1] OperationTag,
+	msg		[2] RsproPDUchoice
+}
+
+END