import sccp_scrc and sccp_scoc from old osmo_ss7 repository

osmo_ss7 is responsible for the mtp2/mtp3/m2ua/m3ua/ipa type links,
while we collect all actual SCCP related functionality here.

5 files changed, 758 insertions, 0 deletions

diff --git a/README b/README
new file mode 100644
index 0000000..1fef5c2
--- /dev/null
+++ b/README
@@ -0,0 +1,56 @@
+= Osmocom Erlang SCCP implementation =
+
+This is a currently still incomplete Erlang SCCP implementation which
+is part of the overall Osmocom project (http://osmocom.org/)
+
+The aim is to fully implement SCCP for connectionless and connection-
+oriented services, including global title translation.  It should be
+possible to use this as both STP or SCP, or even as an ITP/SGW.
+
+
+== Configuration ==
+
+The SCCP stack is configured via the regular OTP application configuration
+file.
+
+
+=== Signalling linksets and links ===
+
+The MTP functionality can be provided by either M3UA or a classic MTP3 (over
+M2UA or real MTP2).
+
+A linkset is a group of links, all connected to the same destination (point
+code).
+
+Each signalling linkset has to be configured in the config file, providing
+the following parameters:
+ * linkset name
+ * local point code
+ * remote point code
+
+Each signalling link has to be configured in the config file, providing the
+following parameters:
+ * linkset name
+ * SLS
+ * IP address and port information (for M3UA)
+
+The sccp_links module keeps track of signalling linksets and links by means of
+ets tables.  It maintains a record of the Erlang process pid responsible for
+each respective link.
+
+== Architecture ==
+
+osmo_sccp_app starts osmo_sccp_sup, which in turn starts the individual signalling
+links through the respective signalling link provider modules.
+
+It also starts sccp_scrc (the SCCP routing) 
+
+One sccp_scoc instance will be started for each SCCP connection.
+
+== Implementing a SCCP-user ==
+
+== Implementing a MTP provider for SCCP ==
+
+This section outlines how to write a MTP transport for the SCCP stack.
+
+FIXME
diff --git a/ebin/osmo_sccp.app b/ebin/osmo_sccp.app
index 000ce84..e9f9b78 100644
--- a/ebin/osmo_sccp.app
+++ b/ebin/osmo_sccp.app
@@ -8,6 +8,8 @@
 			sccp_link_ipa_client,
 			sccp_link_m3ua,
 			sccp_routing,
+			sccp_scrc,
+			sccp_scoc,
 			sccp_user
 		]},
 	 {registered, [osmo_sccp_app]},
diff --git a/include/osmo_sccp.hrl b/include/osmo_sccp.hrl
new file mode 100644
index 0000000..5dea6a3
--- /dev/null
+++ b/include/osmo_sccp.hrl
@@ -0,0 +1,17 @@
+
+-record(sigtran_peer, {
+	ip,
+	port,
+	point_code
+}).
+
+-record(sigtran_link, {
+	type,
+	name,
+	linkset_name,
+	sls,
+	local,
+	remote
+}).
+
+
diff --git a/src/sccp_scoc.erl b/src/sccp_scoc.erl
new file mode 100644
index 0000000..d617216
--- /dev/null
+++ b/src/sccp_scoc.erl
@@ -0,0 +1,474 @@
+% ITU-T Q.71x SCCP Connection-oriented Control (SCOC)
+
+% (C) 2010 by Harald Welte <laforge@gnumonks.org>
+%
+% All Rights Reserved
+%
+% This program is free software; you can redistribute it and/or modify
+% it under the terms of the GNU Affero General Public License as
+% published by the Free Software Foundation; either version 3 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 Affero General Public License
+% along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+-module(sccp_scoc).
+-behaviour(gen_fsm).
+
+-include_lib("osmo_ss7/include/osmo_util.hrl").
+-include_lib("osmo_ss7/include/sccp.hrl").
+
+-export([start_link/1]).
+
+-export([init/1, handle_event/3]).
+-export([idle/2, conn_pend_in/2, conn_pend_out/2, active/2, disconnect_pending/2,
+	 reset_incoming/2, reset_outgoing/2, bothway_reset/2, wait_conn_conf/2]).
+
+%% gen_fsm callbacks
+
+% Appendix C.4 of Q.714 (all in milliseconds)
+-define(CONNECTION_TIMER,	1  *60*100).
+-define(TX_INACT_TIMER,		5  *60*100).
+-define(RX_INACT_TIMER,		11 *60*100).
+-define(RELEASE_TIMER,		10 *100).
+-define(RELEASE_REP_TIMER,	10 *100).
+-define(INT_TIMER,		1  *60*100).
+-define(GUARD_TIMER,		23 *60*100).
+-define(RESET_TIMER,		10 *100).
+-define(REASSEMBLY_TIMER,	10 *60*100).
+
+-record(state, {
+	  role,			% client | server
+	  user_application,	% {MonitorRef, pid()}
+	  scrc_pid,		% pid()
+	  rx_inact_timer,	% TRef
+	  tx_inact_timer,	% TRef
+	  local_reference,
+	  remote_reference,
+	  class,
+	  user_pid		% pid()
+	}).
+
+% TODO: 
+% 	expedited data
+%	class 3
+%	segmentation / reassembly
+
+start_link(InitOpts) ->
+	gen_fsm:start_link(sccp_scoc, InitOpts, [{debug, [trace]}]).
+
+init(InitOpts) ->
+	LoopDat = #state{user_pid=proplists:get_value(user_pid, InitOpts),
+			 scrc_pid=proplists:get_value(scrc_pid, InitOpts),
+			 local_reference=proplists:get_value(local_reference, InitOpts)},
+	io:format("SCOC init Pid=~p LoopDat ~p~n", [self(), LoopDat]),
+	{ok, idle, LoopDat}.
+
+handle_event(stop, _StateName, LoopDat) ->
+	io:format("SCOC received stop event~n"),
+	{stop, normal, LoopDat};
+handle_event({timer_expired, tx_inact_timer}, State, LoopDat) ->
+	% FIXME: T(ias) is expired, send IT message
+	io:format("T(ias) is expired, send IT message~n", []),
+	#state{local_reference = LocRef, remote_reference = RemRef,
+	       class = Class} = LoopDat,
+	Params = [{dst_local_ref, RemRef},{src_local_ref, LocRef},
+		  {protocol_class, Class}, {seq_segm, 0}, {credit, 0}],
+	Msg = #sccp_msg{msg_type = ?SCCP_MSGT_IT, parameters = Params},
+	gen_fsm:send_event(LoopDat#state.scrc_pid,
+			   osmo_util:make_prim('OCRC','CONNECTION-MSG', request, Msg)),
+	{next_state, State, LoopDat};
+handle_event({timer_expired, rx_inact_timer}, State, LoopDat) ->
+	io:format("FIXME: T(iar) is expired, release connection~n", []),
+	% FIXME: Initiate connection release procedure
+	{next_state, State, LoopDat}.
+
+% helper function to send a primitive to the user
+send_user(_LoopDat = #state{user_pid = Pid}, Prim = #primitive{}) ->
+	Pid ! {sccp, Prim}.
+
+% low-level functions regarding activity timers
+restart_tx_inact_timer(LoopDat) ->
+	Tias = timer:apply_after(?TX_INACT_TIMER, gen_fsm, send_all_state_event,
+				 [self(), {timer_expired, tx_inact_timer}]),
+	LoopDat#state{tx_inact_timer = Tias}.
+
+restart_rx_inact_timer(LoopDat) ->
+	Tiar = timer:apply_after(?RX_INACT_TIMER, gen_fsm, send_all_state_event,
+				 [self(), {timer_expired, rx_inact_timer}]),
+	LoopDat#state{rx_inact_timer = Tiar}.
+	
+start_inact_timers(LoopDat) ->
+	Tias = timer:apply_after(?TX_INACT_TIMER, gen_fsm, send_all_state_event,
+				 [self(), {timer_expired, tx_inact_timer}]),
+	Tiar = timer:apply_after(?RX_INACT_TIMER, gen_fsm, send_all_state_event,
+				 [self(), {timer_expired, rx_inact_timer}]),
+	LoopDat#state{rx_inact_timer = Tiar, tx_inact_timer = Tias}.
+
+stop_inact_timers(#state{rx_inact_timer = Tiar, tx_inact_timer = Tias}) ->
+	timer:cancel(Tiar),
+	timer:cancel(Tias).
+
+
+% -spec idle(#primitive{} | ) -> gen_fsm_state_return().
+
+% STATE Idle
+
+% N-CONNECT.req from user
+idle(#primitive{subsystem = 'N', gen_name = 'CONNECT',
+	        spec_name = request, parameters = Param}, LoopDat) ->
+	% local reference already assigned in SCRC when instantiating this SCOC
+	% FIXME: determine protocol class and credit
+	gen_fsm:send_event(LoopDat#state.scrc_pid,
+			   osmo_util:make_prim('OCRC','CONNECTION', indication, Param)),
+	% start connection timer
+	{next_state, conn_pend_out, LoopDat, ?CONNECTION_TIMER};
+
+% RCOC-CONNECTION.req from SCRC
+idle(#primitive{subsystem = 'RCOC', gen_name = 'CONNECTION',
+		spec_name = indication, parameters = Params}, LoopDat) ->
+	% associate remote reference to connection section
+	RemRef = proplists:get_value(src_local_ref, Params),
+	% determine protocol class and FIXME: credit
+	Class = proplists:get_value(protocol_class, Params),
+	LoopDat1 = LoopDat#state{remote_reference = RemRef, class = Class},
+	% send N-CONNECT.ind to user
+	send_user(LoopDat1, osmo_util:make_prim('N', 'CONNECT', indication, [{scoc_pid, self()}|Params])),
+	%#primitive{subsystem = 'N', gen_name = 'CONNECT', spec_name = indication}
+	{next_state, conn_pend_in, LoopDat1};
+
+% RCOC-ROUTING_FAILURE.ind from SCRC
+idle(#primitive{subsystem = 'RCOC', gen_name = 'ROUTING FAILURE',
+		spec_name = indication}, LoopDat) ->
+	gen_fsm:send_event(LoopDat#state.scrc_pid,
+			   osmo_util:make_prim('OCRC', 'CONNECTION REFUSED', indication)),
+	{next_state, idle, LoopDat};
+
+%FIXME: request type 2 ?!?
+
+% RCOC-RELEASED.ind from SCRC
+idle(#primitive{subsystem = 'RCOC', gen_name = 'RELEASED',
+		spec_name = indication}, LoopDat) ->
+	gen_fsm:send_event(LoopDat#state.scrc_pid,
+			   osmo_util:make_prim('OCRC', 'RELEASE COMPLETE', indication)),
+	{next_state, idle, LoopDat};
+
+% RCOC-RELEASE_COMPLETE.ind from SCRC
+idle(#primitive{subsystem = 'RCOC', gen_name = 'RELEASE COMPLETE',
+		spec_name = indication}, LoopDat) ->
+	{next_state, idle, LoopDat};
+
+idle(#primitive{subsystem= 'RCOC', gen_name = 'DATA',
+		spec_name = indication, parameters = Param}, LoopDat) ->
+	% FIXME: if source reference, send error
+	send_user(LoopDat, osmo_util:make_prim('N', 'DATA', indication, Param)),
+	{next_state, idle, LoopDat}.
+
+% STATE Connection pending incoming
+conn_pend_in(#primitive{subsystem = 'N', gen_name = 'CONNECT',
+			spec_name = response, parameters = Param}, LoopDat) ->
+	io:format("SCOC N-CONNECT.resp LoopDat ~p~n", [LoopDat]),
+	% assign local reference, SLS, protocol class and credit for inc section
+	OutParam = [{dst_local_ref, LoopDat#state.remote_reference},
+		    {src_local_ref, LoopDat#state.local_reference},
+		    {protocol_class, LoopDat#state.class}] ++ Param,
+	gen_fsm:send_event(LoopDat#state.scrc_pid,
+			   osmo_util:make_prim('OCRC', 'CONNECTION', confirm, OutParam)),
+	% start inactivity timers
+	LoopDat1 = start_inact_timers(LoopDat),
+	{next_state, active, LoopDat1};
+conn_pend_in(any_npdu_type, LoopDat) ->
+	{next_state, conn_pend_in, LoopDat};
+conn_pend_in(#primitive{subsystem = 'N', gen_name = 'DISCONNECT',
+			spec_name = request, parameters = Param}, LoopDat) ->
+	% release resourcers (local ref may have to be released an frozen)
+	gen_fsm:send_event(LoopDat#state.scrc_pid,
+			   osmo_util:make_prim('OCRC', 'CONNECTION REFUSED', indication, Param)),
+	{next_state, idle, LoopDat}.
+	
+
+disc_ind_stop_rel_3(LoopDat) ->
+	% send N-DISCONNECT.ind to user
+	send_user(LoopDat, osmo_util:make_prim('N', 'DISCONNECT',indication)),
+	% stop inactivity timers
+	stop_inact_timers(LoopDat),
+	gen_fsm:send_event(LoopDat#state.scrc_pid,
+			   osmo_util:make_prim('OCRC', 'RELEASED', indication)),
+	% start release timer
+	{next_state, disconnect_pending, LoopDat, ?RELEASE_TIMER}.
+
+rel_res_disc_ind_idle_2(LoopDat) ->
+	% release resources and local reference (freeze)
+	% send N-DISCONNECT.ind to user
+	send_user(LoopDat, osmo_util:make_prim('N', 'DISCONNECT', indication)),
+	{next_state, idle, LoopDat}.
+
+
+% STATE Connection pending outgoing
+conn_pend_out(#primitive{subsystem = 'N', gen_name = 'DISCONNECT',
+			 spec_name = request}, LoopDat) ->
+	% FIXME: what about the connection timer ?
+	{next_state, wait_conn_conf, LoopDat};
+conn_pend_out(timeout, LoopDat) ->
+	rel_res_disc_ind_idle_2(LoopDat);
+conn_pend_out(routing_failure, LoopDat) ->
+	rel_res_disc_ind_idle_2(LoopDat);
+conn_pend_out(released, LoopDat) ->
+	gen_fsm:send_event(LoopDat#state.scrc_pid,
+			   osmo_util:make_prim('OCRC',  'RELEASE COMPLETE', indication)),
+	rel_res_disc_ind_idle_2(LoopDat);
+% other N-PDU Type
+conn_pend_out(other_npdu_type, LoopDat) ->
+	rel_res_disc_ind_idle_2(LoopDat);
+conn_pend_out(connection_refused, LoopDat) ->
+	rel_res_disc_ind_idle_2(LoopDat);
+conn_pend_out(connection_confirm, LoopDat) ->
+	% start inactivity timers
+	LoopDat1 = start_inact_timers(LoopDat),
+	% assign protocol class and associate remote reference to connection
+	% send N-CONNECT.conf to user
+	send_user(LoopDat1, #primitive{subsystem = 'N', gen_name = 'CONNECT',
+				       spec_name = confirm}),
+	{next_state, active, LoopDat1}.
+
+stop_c_tmr_rel_idle_5(LoopDat) ->
+	% stop connection timer (implicit)
+	% release resources and local reference
+	{next_state, idle, LoopDat}.
+
+rel_freeze_idle(LoopDat) ->
+	{next_state, idle, LoopDat}.
+
+% STATE Wait connection confirmed
+wait_conn_conf(released, LoopDat) ->
+	gen_fsm:send_event(LoopDat#state.scrc_pid,
+			   osmo_util:make_prim('OCRC', 'RELEASE COMPLETE', indication)),
+	stop_c_tmr_rel_idle_5(LoopDat);
+wait_conn_conf(connection_confirm, LoopDat) ->
+	% stop connection timer (implicit)
+	% associate remote reference to connection
+	relsd_tmr_disc_pend_6(LoopDat);
+wait_conn_conf(other_npdu_type, LoopDat) ->
+	% stop connection timer (implicit)
+	rel_freeze_idle(LoopDat);
+wait_conn_conf(timeout, LoopDat) ->
+	stop_c_tmr_rel_idle_5(LoopDat);
+wait_conn_conf(connection_refused, LoopDat) ->
+	stop_c_tmr_rel_idle_5(LoopDat);
+wait_conn_conf(routing_failure, LoopDat) ->
+	stop_c_tmr_rel_idle_5(LoopDat).
+
+
+relsd_tmr_disc_pend_6(LoopDat) ->
+	gen_fsm:send_event(LoopDat#state.scrc_pid,
+			   osmo_util:make_prim('OCRC', 'RELEASED', indication)),
+	% start release timer
+	{next_state, disconnect_pending, LoopDat, ?RELEASE_TIMER}.
+
+% STATE Active
+active(#primitive{subsystem = 'N', gen_name = 'DISCONNECT',
+		  spec_name = request}, LoopDat) ->
+	% stop inactivity timers
+	start_inact_timers(LoopDat),
+	relsd_tmr_disc_pend_6(LoopDat);
+active(internal_disconnect, LoopDat) ->
+	disc_ind_stop_rel_3(LoopDat);
+active(connection_refused, LoopDat) ->
+	{next_state, active, LoopDat};
+active(connection_confirm, LoopDat) ->
+	{next_state, active, LoopDat};
+active(release_complete, LoopDat) ->
+	{next_state, active, LoopDat};
+active(released, LoopDat) ->
+	% send N-DISCONNECT.ind to user
+	send_user(LoopDat, #primitive{subsystem = 'N', gen_name = 'DISCONNECT',
+				      spec_name = indication}),
+	% release resources and local reference (freeze)
+	% stop inactivity timers
+	stop_inact_timers(LoopDat),
+	gen_fsm:send_event(LoopDat#state.scrc_pid,
+			   osmo_util:make_prim('OCRC', 'RELEASE COMPLETE', indication)),
+	{next_state, idle, LoopDat};
+active(error, LoopDat) ->
+	% send N-DISCONNECT.ind to user
+	send_user(LoopDat, #primitive{subsystem = 'N', gen_name = 'DISCONNECT',
+				      spec_name = indication}),
+	% release resources and local reference (freeze)
+	% stop inactivity timers
+	stop_inact_timers(LoopDat),
+	gen_fsm:send_event(LoopDat#state.scrc_pid,
+			   osmo_util:make_prim('OCRC', 'RELEASE COMPLETE', indication)),
+	{next_state, idle, LoopDat};
+active(rcv_inact_tmr_exp, LoopDat) ->
+	disc_ind_stop_rel_3(LoopDat);
+active(routing_failure, LoopDat) ->
+	% send N-DISCONNECT.ind to user
+	send_user(LoopDat, #primitive{subsystem = 'N', gen_name = 'DISCONNECT',
+				      spec_name = indication}),
+	% stop inactivity timers
+	stop_inact_timers(LoopDat),
+	% start release timer
+	{next_state, disconnect_pending, LoopDat, ?RELEASE_TIMER};
+% Connection release procedures at destination node
+%active(internal_disconnect) ->
+% Data transfer procedures
+active(#primitive{subsystem = 'N', gen_name = 'DATA',
+		  spec_name = request, parameters = Param}, LoopDat) ->
+	% FIXME Segment NSDU and assign value to bit M
+	% FIXME handle protocol class 3
+	gen_fsm:send_event(LoopDat#state.scrc_pid, {dt1, []}),
+	% restart send inactivity timer
+	LoopDat1 = restart_tx_inact_timer(LoopDat),
+	{next_state, active, LoopDat1};
+active(#primitive{subsystem = 'RCOC', gen_name = 'CONNECTION-MSG',
+		  spec_name = indication, parameters = Msg}, LoopDat) ->
+	% restart receive inactivity timer
+	LoopDat1 = restart_rx_inact_timer(LoopDat),
+	% FIXME handle protocol class 3
+	% FIXME check for M-bit=1 and put data in Rx queue
+	% N-DATA.ind to user
+	UserData = proplists:get_value(user_data, Msg#sccp_msg.parameters),
+	send_user(LoopDat, osmo_util:make_prim('N', 'DATA', indication, {user_data, UserData})),
+	{next_state, active, LoopDat1};
+% Reset procedures
+active(#primitive{subsystem = 'N', gen_name = 'RESET',
+		  spec_name = request, parameters = Param}, LoopDat) ->
+	gen_fsm:send_event(LoopDat#state.scrc_pid,
+			   osmo_util:make_prim('OCRC', 'RESET', request, Param)),
+	% start reset timer
+	% restart send inact timer
+	LoopDat1 = restart_tx_inact_timer(LoopDat),
+	% reset variables and discard all queued and unacked msgs
+	{next_state, reset_outgoing, LoopDat1, ?RESET_TIMER};
+active(internal_reset_req, LoopDat) ->
+	% N-RESET.ind to user
+	send_user(LoopDat, #primitive{subsystem = 'N', gen_name = 'RESET',
+				      spec_name = indication}),
+	gen_fsm:send_event(LoopDat#state.scrc_pid,
+			   osmo_util:make_prim('OCRC', 'RESET', request)),
+	% start reset timer
+	% restart send inact timer
+	LoopDat1 = restart_tx_inact_timer(LoopDat),
+	% reset variables and discard all queued and unacked msgs
+	{next_state, bothway_reset, LoopDat1, ?RESET_TIMER};
+active(reset_confirm, LoopDat) ->
+	% discard received message
+	{next_state, active, LoopDat};
+active(reset_req, LoopDat) ->
+	% restart send inactivity timer
+	LoopDat1 = restart_tx_inact_timer(LoopDat),
+	% N-RESET.ind to user
+	send_user(LoopDat, osmo_util:make_prim('N', 'RESET', indication)),
+	% reset variables and discard all queued and unacked msgs
+	{next_state, reset_incoming, LoopDat1}.
+
+rel_res_stop_tmr_12(LoopDat) ->
+	% release resources and local reference (freeze)
+	% stop release and interval timers
+	{next_state, idle, LoopDat}.
+
+% STATE Disconnect pending
+disconnect_pending(release_complete, LoopDat) ->
+	rel_res_stop_tmr_12(LoopDat);
+disconnect_pending(released_error, LoopDat) ->
+	rel_res_stop_tmr_12(LoopDat);
+disconnect_pending(routing_failure, LoopDat) ->
+	{next_state, disconnect_pending, LoopDat};
+disconnect_pending(other_npdu_type, LoopDat) ->
+	% discared received message
+	{next_state, disconnect_pending, LoopDat};
+disconnect_pending(timeout, LoopDat) ->
+	gen_fsm:send_event(LoopDat#state.scrc_pid,
+			   osmo_util:make_prim('OCRC', 'RELEASED', indication)),
+	% start interval timer
+	% FIXME start repeat release timer
+	{next_state, disconnect_pending, ?RELEASE_REP_TIMER};
+disconnect_pending(intv_tmr_exp, LoopDat) ->
+	% inform maintenance
+	rel_res_stop_tmr_12(LoopDat);
+% FIXME: this is currently ending up in normal 'timeout' above
+disconnect_pending(repeat_release_tmr_exp, LoopDat) ->
+	gen_fsm:send_event(LoopDat#state.scrc_pid,
+			   osmo_util:make_prim('OCRC', 'RELEASED', indication)),
+	% FIXME restart repeat release timer
+	{next_state, disconnect_pending}.
+
+res_out_res_conf_req(LoopDat) ->
+	% N-RESET.conf to user
+	send_user(LoopDat, osmo_util:make_prim('N', 'RESET', confirm)),
+	% stop reset timer (implicit)
+	% restart receive inactivity timer
+	LoopDat1 = restart_rx_inact_timer(LoopDat),
+	% resume data transfer
+	{next_state, active, LoopDat1}.
+
+% STATE Reset outgoing
+reset_outgoing(#primitive{subsystem = 'N', gen_name = 'DATA',
+			  spec_name = request, parameters = Params}, LoopDat) ->
+	% FIXME received information ?!?
+	{next_state, reset_outgoing, LoopDat};
+reset_outgoing(#primitive{subsystem = 'N', gen_name = 'EXPEDITED DATA',
+			  spec_name = request, parameters = Params}, LoopDat) ->
+	% FIXME received information ?!?
+	{next_state, reset_outgoing, LoopDat};
+reset_outgoing(timeout, LoopDat) ->
+	% FIXME check for temporary connection section
+	% inform maintenance
+	{next_state, maintenance_Blocking, LoopDat};
+%reset_outgoing(error, LoopDat) ->
+%reset_outgoing(released, LoopDat) ->
+reset_outgoing(other_npdu_type, LoopDat) ->
+	% discard received message
+	{next_state, reset_outgoing, LoopDat};
+reset_outgoing(reset_confirm, LoopDat) ->
+	res_out_res_conf_req(LoopDat);
+reset_outgoing(reset_request, LoopDat) ->
+	res_out_res_conf_req(LoopDat).
+
+bway_res_req_resp(LoopDat) ->
+	{next_state, reset_outgoing, LoopDat}.
+
+bway_res_res_conf_req(LoopDat) ->
+	% N-RESET.conf to user
+	send_user(LoopDat, #primitive{subsystem = 'N', gen_name = 'RESET',
+				      spec_name = confirm}),
+	% stop reset timer (implicit)
+	% restart receive inactivity timer
+	LoopDat1 = restart_rx_inact_timer(LoopDat),
+	{next_state, reset_incoming, LoopDat1}.
+
+% STATE Bothway Reset
+bothway_reset(#primitive{subsystem = 'N', gen_name = 'RESET',
+			 spec_name = request, parameters = Params}, LoopDat) ->
+	bway_res_req_resp(LoopDat);
+bothway_reset(#primitive{subsystem = 'N', gen_name = 'RESET',
+			 spec_name = response, parameters = Params}, LoopDat) ->
+	bway_res_req_resp(LoopDat);
+bothway_reset(timeout, LoopDat) ->
+	% FIXME check for temporary connection section
+	% inform maintenance
+	{next_state, maintenance_Blocking, LoopDat};
+%bothway_reset(error, LoopDat) ->
+%bothway_reset(released, LoopDat) ->
+bothway_reset(other_npdu_type, LoopDat) ->
+	% discard received message
+	{next_state, bothway_reset, LoopDat}.
+
+% STATE Reset incoming
+reset_incoming(#primitive{subsystem = 'N', gen_name = 'RESET',
+			  spec_name = request, parameters = Params}, LoopDat) ->
+	% received information
+	{nest_state, reset_incoming, LoopDat};
+%reset_incoming(error, LoopDat) ->
+%reset_incoming(released, LoopDat) ->
+reset_incoming(other_npdu_type, LoopDat) ->
+	% discard received message
+	% internal reset request
+	{next_state, active, LoopDat}.
+% FIXME: response or request
+%reset_incoming(
diff --git a/src/sccp_scrc.erl b/src/sccp_scrc.erl
new file mode 100644
index 0000000..3c10c8e
--- /dev/null
+++ b/src/sccp_scrc.erl
@@ -0,0 +1,209 @@
+% SCCP routing control procedures (SCRC)
+
+% (C) 2010-2011 by Harald Welte <laforge@gnumonks.org>
+%
+% All Rights Reserved
+%
+% This program is free software; you can redistribute it and/or modify
+% it under the terms of the GNU Affero General Public License as
+% published by the Free Software Foundation; either version 3 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 Affero General Public License
+% along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+-module(sccp_scrc).
+-behaviour(gen_fsm).
+-export([start_link/1, init/1, terminate/3, idle/2]).
+
+-include_lib("osmo_ss7/include/osmo_util.hrl").
+-include_lib("osmo_ss7/include/sccp.hrl").
+-include_lib("osmo_ss7/include/mtp3.hrl").
+
+
+
+-record(scrc_state, {
+		scoc_conn_ets,
+		next_local_ref,
+		user_pid	% pid() of the user process
+	}).
+% TODO: Integrate with proper SCCP routing / GTT implementation
+
+tx_prim_to_local_ref(Prim, LocalRef) ->
+	% determine the Pid to which the primitive must be sent
+	ConnTable = get(scoc_by_ref),
+	case ets:lookup(ConnTable, LocalRef) of
+		[{LocalRef, ScocPid}] ->
+			gen_fsm:send_event(ScocPid, Prim);
+		_ ->
+			io:format("Primitive ~p for unknown local reference ~p~n",
+				  [Prim, LocalRef])
+	end.
+
+
+start_link(InitData) ->
+	% make sure to store the Pid of the caller in the scrc_state
+	gen_fsm:start_link({local, sccp_scrc}, sccp_scrc, 
+			   [{user_pid,self()}|InitData], [{debug, [trace]}]).
+
+% gen_fsm init callback, called by start_link()
+init(InitPropList) ->
+	io:format("SCRC Init PropList~p ~n", [InitPropList]),
+	UserPid = proplists:get_value(user_pid, InitPropList),
+	LoopData = #scrc_state{user_pid = UserPid, next_local_ref = 0},
+	TableRef = ets:new(scoc_by_ref, [set]),
+	put(scoc_by_ref, TableRef),
+	{ok, idle, LoopData}.
+
+
+terminate(Reason, _State, _LoopDat) ->
+	io:format("SCRC: Terminating with reason ~p~n", [Reason]),
+	Tref = get(scoc_by_ref),
+	ets:delete(Tref),
+	ok.
+
+% helper function to create new SCOC instance
+spawn_new_scoc(LoopDat) ->
+	% create new SCOC instance
+	UserPid = LoopDat#scrc_state.user_pid,
+	% Compute the new local reference
+	LocalRef = LoopDat#scrc_state.next_local_ref + 1,
+	LoopDat1 = LoopDat#scrc_state{next_local_ref = LocalRef},
+	% generate proplist for SCRC initialization
+	ScocPropList = [{scrc_pid, self()}, {user_pid, UserPid}, {local_reference, LocalRef}],
+	{ok, ScocPid} = sccp_scoc:start_link(ScocPropList),
+	% insert SCOC instance in connection table
+	ConnTable = get(scoc_by_ref),
+	ets:insert_new(ConnTable, {LocalRef, ScocPid}),
+	{LoopDat1, ScocPid}.
+
+is_cr_or_connless(SccpMsg) when is_record(SccpMsg, sccp_msg) ->
+	case SccpMsg of
+		#sccp_msg{msg_type = ?SCCP_MSGT_CR} ->
+			true;
+		_ ->
+			sccp_codec:is_connectionless(SccpMsg)
+	end.
+
+% deliver message to local SCOC or SCLC
+deliver_to_scoc_sclc(LoopDat, Msg) when is_record(Msg, sccp_msg) ->
+	case Msg of
+		% special handling for CR message here in SCRC
+		#sccp_msg{msg_type = ?SCCP_MSGT_CR} ->
+			% spawn a new SCOC instance/process
+			{LoopDat1, ScocPid} = spawn_new_scoc(LoopDat),
+			% send a RCOC-CONNECTING.ind primitive to the new SCOC fsm
+			UserPrim = osmo_util:make_prim('RCOC','CONNECTION', indication, Msg#sccp_msg.parameters),
+			io:format("Sending ~p to ~p~n", [UserPrim, ScocPid]),
+			gen_fsm:send_event(ScocPid, UserPrim),
+			LoopDat1;
+		% T(ias) expired on the other end of the connection
+		%#sccp_msg{msg_type = ?SCCP_MSGT_IT} ->
+		_ ->
+			IsConnLess = sccp_codec:is_connectionless(Msg),
+			case IsConnLess of
+				true ->
+					% it would be more proper to send them via SCLC ??
+					%gen_fsm:send(sccp_sclc, ??
+					UserPid = LoopDat#scrc_state.user_pid,
+					% FIXME: N-NOTICE.ind for NOTICE 
+					UserPrim = osmo_util:make_prim('N','UNITDATA', indication, Msg),
+					UserPid ! {sccp, UserPrim};
+				false ->
+					% connection oriented messages need to go via SCOC instance
+					#sccp_msg{parameters = Opts} = Msg,
+					LocalRef = proplists:get_value(dst_local_ref, Opts),
+					ScocPrim = osmo_util:make_prim('RCOC', 'CONNECTION-MSG', indication, Msg),
+					case LocalRef of
+						undefined ->
+							% FIXME: send SCCP_MSGT_ERR
+							io:format("Conn-Msg to undefined ref ~p~n", [Msg]);
+						_ ->
+							tx_prim_to_local_ref(ScocPrim, LocalRef)
+					end
+			end,
+			LoopDat
+	end.
+
+
+% N-CONNECT.req from user: spawn new SCOC and deliver primitive to it
+idle(P = #primitive{subsystem = 'N', gen_name = 'CONNECT',
+		    spec_name = request, parameters = Params}, LoopDat) ->
+	% Start new SCOC instance
+	{LoopDat1, ScocPid} = spawn_new_scoc(LoopDat),
+	% Deliver primitive to new SCOC instance
+	gen_fsm:send_event(ScocPid, P),
+	{next_state, idle, LoopDat1};
+
+% N-UNITDATA.req from user (normally this is SCLC, but we don't have SCLC)
+idle(P= #primitive{subsystem = 'N', gen_name = 'UNITDATA',
+		   spec_name = request, parameters = Params}, LoopDat) ->
+	% User needs to specify: Protocol Class, Called Party, Calling Party, Data
+	% FIXME: implement XUDT / LUDT support
+	% encode the actual SCCP message
+	EncMsg = sccp_codec:encode_sccp_msgt(?SCCP_MSGT_UDT, Params),
+	% generate a MTP-TRANSFER.req primitive to the lower layer
+	send_mtp_transfer_down(LoopDat, EncMsg),
+	{next_state, idle, LoopDat};
+% MTP-TRANSFER.ind from lower layer is passed into SCRC
+idle(#primitive{subsystem = 'MTP', gen_name = 'TRANSFER',
+		spec_name = indication, parameters = Params}, LoopDat) ->
+	case sccp_routing:route_mtp3_sccp_in(Params) of
+		{remote} ->
+			% routing has taken care of it 
+			LoopDat1 = LoopDat;
+		{local, SccpMsg, _} ->
+			LoopDat1 = deliver_to_scoc_sclc(LoopDat, SccpMsg)
+	end,
+	{next_state, idle, LoopDat1};
+idle({sclc_scrc_connless_msg, SccpMsg}, LoopDat) ->
+	case sccp_routing:route_local_out(SccpMsg) of
+		{remote, SccpMsg2} ->
+			% FIXME: get to MTP-TRANSFER.req
+			LoopDat1 = LoopDat;
+		{error, _} ->
+			LoopDat1 = LoopDat;
+		{local, SccpMsg2} ->
+			LoopDat1 = deliver_to_scoc_sclc(LoopDat, SccpMsg2)
+	end,
+	{next_state, idle, LoopDat};
+% connection oriented messages like N-DATA.req from user
+idle(#primitive{subsystem = 'OCRC', gen_name = 'CONNECTION-MSG',
+		spec_name = request, parameters = Msg}, LoopDat) ->
+	% encode the actual SCCP message
+	EncMsg = sccp_codec:encode_sccp_msg(Msg),
+	% generate a MTP-TRANSFER.req primitive to the lower layer
+	send_mtp_transfer_down(LoopDat, EncMsg),
+	{next_state, idle, LoopDat};
+% SCOC has received confirmation about new incoming connection from user
+idle(#primitive{subsystem = 'OCRC', gen_name = 'CONNECTION',
+		spec_name = confirm, parameters = Params}, LoopDat) ->
+	% encode the actual SCCP message
+	EncMsg = sccp_codec:encode_sccp_msgt(?SCCP_MSGT_CC, Params),
+	% generate a MTP-TRANSFER.req primitive to the lower layer
+	send_mtp_transfer_down(LoopDat, EncMsg),
+	{next_state, idle, LoopDat};
+
+
+% triggered by N-CONNECT.req from user to SCOC:
+idle(#primitive{subsystem = 'OCRC', gen_name = 'CONNECTION',
+		spec_name = indication, parameters = Params}, LoopDat) ->
+	% encode the actual SCCP message
+	EncMsg = sccp_codec:encode_sccp_msgt(?SCCP_MSGT_CR, Params),
+	% generate a MTP-TRANSFER.req primitive to the lower layer
+	send_mtp_transfer_down(LoopDat, EncMsg),
+	{next_state, idle, LoopDat}.
+
+send_mtp_transfer_down(LoopDat, EncMsg) ->
+	Rlbl = #mtp3_routing_label{sig_link_sel = 0, origin_pc = 123, dest_pc = 456},
+	Mtp3 = #mtp3_msg{network_ind = ?MTP3_NETIND_INTERNATIONAL,
+			 service_ind = ?MTP3_SERV_SCCP,
+			 routing_label = Rlbl, payload = EncMsg},
+	MtpPrim = #primitive{subsystem = 'MTP', gen_name = 'TRANSFER',
+			     spec_name = request, parameters = Mtp3},
+	sccp_links:mtp3_tx(Mtp3).