add missing gsup_client.erl
diff --git a/src/gsup_client.erl b/src/gsup_client.erl
new file mode 100644
index 0000000..05eddb1
--- /dev/null
+++ b/src/gsup_client.erl
@@ -0,0 +1,101 @@
+% simple, blocking/synchronous GSUP client
+
+% (C) 2019 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/>.
+%
+% Additional Permission under GNU AGPL version 3 section 7:
+%
+% If you modify this Program, or any covered work, by linking or
+% combining it with runtime libraries of Erlang/OTP as released by
+% Ericsson on http://www.erlang.org (or a modified version of these
+% libraries), containing parts covered by the terms of the Erlang Public
+% License (http://www.erlang.org/EPLICENSE), the licensors of this
+% Program grant you additional permission to convey the resulting work
+% without the need to license the runtime libraries of Erlang/OTP under
+% the GNU Affero General Public License. Corresponding Source for a
+% non-source form of such a combination shall include the source code
+% for the parts of the runtime libraries of Erlang/OTP used as well as
+% that of the covered work.
+
+-module(gsup_client).
+
+-behaviour(gen_server).
+
+-include_lib("osmo_gsup/include/gsup_protocol.hrl").
+
+-define(IPAC_PROTO_EXT_GSUP, {osmo, 5}).
+
+-record(gsupc_state, {
+ socket,
+ ipa_pid
+ }).
+
+-export([start_link/3]).
+
+-export([init/1, handle_call/3, handle_cast/2, handle_info/2]).
+-export([code_change/3, terminate/2]).
+
+%% ------------------------------------------------------------------
+%% our exported API
+%% ------------------------------------------------------------------
+
+start_link(ServerAddr, ServerPort, Options) ->
+ gen_server:start_link(?MODULE, [ServerAddr, ServerPort, Options], [{debug, [trace]}]).
+
+%% ------------------------------------------------------------------
+%% gen_server Function Definitions
+%% ------------------------------------------------------------------
+
+init([Address, Port, Options]) ->
+ ipa_proto:init(),
+ % register the GSUP codec with the IPA core; ignore result as we mgiht be doing this multiple times
+ ipa_proto:register_codec(?IPAC_PROTO_EXT_GSUP, fun gsup_protocol:encode/1, fun gsup_protocol:decode/1),
+ {ok, {Socket, IpaPid}} = ipa_proto:connect(Address, Port, Options),
+ true = ipa_proto:register_stream(Socket, ?IPAC_PROTO_EXT_GSUP, {process_id, self()}),
+ ipa_proto:unblock(Socket),
+ {ok, #gsupc_state{socket=Socket, ipa_pid=IpaPid}}.
+
+
+% send a given GSUP message and synchronously wait for message type ExpRes or ExpErr
+handle_call({transceive_gsup, GsupMsgTx, ExpRes, ExpErr}, _From, State) ->
+ Socket = State#gsupc_state.socket,
+ {ok, Imsi} = maps:find(imsi, GsupMsgTx),
+ ipa_proto:send(Socket, ?IPAC_PROTO_EXT_GSUP, GsupMsgTx),
+ % selective receive for only those GSUP responses we expect
+ receive
+ {ipa, Socket, ?IPAC_PROTO_EXT_GSUP, GsupMsgRx = #{message_type := ExpRes, imsi := Imsi}} ->
+ {reply, GsupMsgRx, State};
+
+ {ipa, Socket, ?IPAC_PROTO_EXT_GSUP, GsupMsgRx = #{message_type := ExpErr, imsi := Imsi}} ->
+ {reply, GsupMsgRx, State}
+ after 5000 ->
+ {reply, timeout, State}
+ end.
+
+handle_cast(Info, S) ->
+ error_logger:error_report(["unknown handle_cast", {module, ?MODULE}, {info, Info}, {state, S}]),
+ {noreply, S}.
+
+handle_info(Info, S) ->
+ error_logger:error_report(["unknown handle_info", {module, ?MODULE}, {info, Info}, {state, S}]),
+ {noreply, S}.
+
+terminate(Reason, _S) ->
+ lager:info("terminating ~p with reason ~p~n", [?MODULE, Reason]).
+
+code_change(_OldVsn, State, _Extra) ->
+ {ok, State}.