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% 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, handle_info/3]).
-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 = ss7_links:bind_service(?MTP3_SERV_SCCP, "osmo_sccp"),
{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, UserPid) 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 ->
case UserPid of
undefined ->
io:format("CL message to unequipped SSN~n");
_ ->
% it would be more proper to send them via SCLC ??
%gen_fsm:send(sccp_sclc, ??
% FIXME: N-NOTICE.ind for NOTICE
UserPrim = osmo_util:make_prim('N','UNITDATA', indication, Msg),
UserPid ! {sccp, UserPrim}
end;
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
SccpMsg = #sccp_msg{msg_type = ?SCCP_MSGT_UDT, parameters = Params},
case sccp_routing:route_local_out(SccpMsg) of
{remote, SccpMsg2, LsName} ->
% FIXME: get to MTP-TRANSFER.req
{ok, M3} = create_mtp3_out(SccpMsg2, LsName),
% generate a MTP-TRANSFER.req primitive to the lower layer
send_mtp_transfer_down(LoopDat, M3, LsName),
LoopDat1 = LoopDat;
{local, SccpMsg2, UserPid} ->
LoopDat1 = deliver_to_scoc_sclc(LoopDat, SccpMsg2, UserPid)
end,
{next_state, idle, LoopDat1};
% 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, SccpMsg2, LsName} ->
{ok, M3} = create_mtp3_out(SccpMsg2, LsName),
% generate a MTP-TRANSFER.req primitive to the lower layer
send_mtp_transfer_down(LoopDat, M3, LsName),
LoopDat1 = LoopDat;
{local, SccpMsg, UserPid} ->
LoopDat1 = deliver_to_scoc_sclc(LoopDat, SccpMsg, UserPid)
end,
{next_state, idle, LoopDat1};
idle({sclc_scrc_connless_msg, SccpMsg}, LoopDat) ->
% FIXME: see above, N-UNITDATA.req from user
{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),
% FIXME: routing and create_mtp3_out()
% 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),
% FIXME: routing and create_mtp3_out()
% 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),
% FIXME: routing and create_mtp3_out()
% 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, Mtp3) when is_record(Mtp3, mtp3_msg) ->
ss7_links:mtp3_tx(Mtp3).
send_mtp_transfer_down(LoopDat, Mtp3, LsName) when is_record(Mtp3, mtp3_msg) ->
ss7_links:mtp3_tx(Mtp3, LsName).
create_mtp3_out(SccpMsg, LsName) when is_record(SccpMsg, sccp_msg) ->
CalledParty = proplists:get_value(called_party_addr,
SccpMsg#sccp_msg.parameters),
% we _have_ to have a destination point code here
Dpc = CalledParty#sccp_addr.point_code,
case Dpc of
undefined ->
{error, dpc_undefined};
_ ->
Opc = sccp_routing:select_opc(SccpMsg, LsName),
case Opc of
undefined ->
{error, opc_undefined};
_ ->
% FIXME: implement XUDT / LUDT support
SccpEnc = sccp_codec:encode_sccp_msg(SccpMsg),
% FIXME: select sls at random
M3R = #mtp3_routing_label{sig_link_sel = 0,
origin_pc = Opc,
dest_pc = Dpc},
M3 = #mtp3_msg{network_ind = ?MTP3_NETIND_INTERNATIONAL,
service_ind = ?MTP3_SERV_SCCP,
routing_label = M3R,
payload = SccpEnc},
{ok, M3}
end
end.
% FIXME: the MTP3 code should net send a gen_serve:cast ?!?
handle_info({'$gen_cast', P=#primitive{}}, State, LoopDat) ->
#primitive{subsystem = 'MTP', gen_name = 'TRANSFER',
spec_name = indication, parameters = Mtp3} = P,
{ok, SccpMsg} = sccp_codec:parse_sccp_msg(Mtp3#mtp3_msg.payload),
% User needs to specify: Protocol Class, Called Party, Calling Party, Data
case sccp_routing:route_local_out(SccpMsg) of
{error, routing} ->
% routing tells us local subsystem not equipped
LoopDat1 = LoopDat;
{remote, SccpMsg2, LsName} ->
% FIXME: get to MTP-TRANSFER.req
{ok, M3} = create_mtp3_out(SccpMsg2, LsName),
% generate a MTP-TRANSFER.req primitive to the lower layer
send_mtp_transfer_down(LoopDat, M3, LsName),
LoopDat1 = LoopDat;
{local, SccpMsg2, UserPid} ->
LoopDat1 = deliver_to_scoc_sclc(LoopDat, SccpMsg2, UserPid)
end,
{next_state, idle, LoopDat1}.
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