[M] Change in ...osmo-epdg[master]: Use call() instead of cast() in ue_fsm - gerrit-log

24 Jan 2024

pespin has uploaded this change for review. ( https://gerrit.osmocom.org/c/erlang/osmo-epdg/+/35675?usp=email )
Change subject: Use call() instead of cast() in ue_fsm
......................................................................
Use call() instead of cast() in ue_fsm
This allows accounting for problems in the FSM from the calling code,
and act accordingly, eg. rejecting a message.
Change-Id: I235d3c8fb3a863d288b5433c39e0da65f747936b
---
M src/gsup_server.erl
M src/ue_fsm.erl
2 files changed, 90 insertions(+), 27 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/erlang/osmo-epdg refs/changes/75/35675/1

diff --git a/src/gsup_server.erl b/src/gsup_server.erl
index 521d4c3..30e8864 100644
--- a/src/gsup_server.erl
+++ b/src/gsup_server.erl
@@ -202,9 +202,18 @@
    {noreply, S#gsups_state{socket=Socket}};
% send auth info / requesting authentication tuples
-handle_info({ipa, _Socket, ?IPAC_PROTO_EXT_GSUP, _GsupMsgRx = #{message_type := send_auth_info_req, imsi := Imsi}}, State0) ->
+handle_info({ipa, Socket, ?IPAC_PROTO_EXT_GSUP, _GsupMsgRx = #{message_type := send_auth_info_req, imsi := Imsi}}, State0) ->
    {UE, State1} = find_or_new_gsups_ue(Imsi, State0),
-	ue_fsm:auth_request(UE#gsups_ue.pid),
+	case ue_fsm:auth_request(UE#gsups_ue.pid) of
+	ok -> ok;
+	{error, _} ->
+		Resp = #{message_type => send_auth_info_err,
+			 imsi => Imsi,
+			 message_class => 5,
+			 cause => ?GSUP_CAUSE_NET_FAIL
+		},
+		tx_gsup(Socket, Resp)
+	end,
    {noreply, State1};
% location update request / when a UE wants to connect to a specific APN. This will trigger a AAA->HLR Request Server Assignment Request
@@ -212,15 +221,24 @@
 handle_info({ipa, Socket, ?IPAC_PROTO_EXT_GSUP, _GsupMsgRx = #{message_type := location_upd_req, imsi := Imsi}}, State) ->
    UE = find_gsups_ue_by_imsi(Imsi, State),
    case UE of
-		#gsups_ue{imsi = Imsi} ->
-			ue_fsm:lu_request(UE#gsups_ue.pid);
-		undefined ->
+	#gsups_ue{imsi = Imsi} ->
+		case ue_fsm:lu_request(UE#gsups_ue.pid) of
+		ok -> ok;
+		{error, _} ->
    		Resp = #{message_type => location_upd_err,
    			 imsi => Imsi,
    			 message_class => 5,
-				 cause => ?GSUP_CAUSE_IMSI_UNKNOWN
+				 cause => ?GSUP_CAUSE_NET_FAIL
    		},
    		tx_gsup(Socket, Resp)
+		end;
+	undefined ->
+		Resp = #{message_type => location_upd_err,
+			 imsi => Imsi,
+			 message_class => 5,
+			 cause => ?GSUP_CAUSE_IMSI_UNKNOWN
+		},
+		tx_gsup(Socket, Resp)
    end,
    {noreply, State};
@@ -230,15 +248,24 @@
    lager:info("GSUP: Rx ~p~n", [GsupMsgRx]),
    UE = find_gsups_ue_by_imsi(Imsi, State),
    case UE of
-		#gsups_ue{imsi = Imsi} ->
-			ue_fsm:tunnel_request(UE#gsups_ue.pid);
-		undefined ->
+	#gsups_ue{imsi = Imsi} ->
+		case ue_fsm:tunnel_request(UE#gsups_ue.pid) of
+		ok -> ok;
+		{error, _} ->
    		Resp = #{message_type => epdg_tunnel_error,
-				 imsi => Imsi,
-				 message_class => 5,
-				 cause => ?GSUP_CAUSE_IMSI_UNKNOWN
+				imsi => Imsi,
+				message_class => 5,
+				cause => ?GSUP_CAUSE_NET_FAIL
    		},
    		tx_gsup(Socket, Resp)
+		end;
+	undefined ->
+		Resp = #{message_type => epdg_tunnel_error,
+				imsi => Imsi,
+				message_class => 5,
+				cause => ?GSUP_CAUSE_IMSI_UNKNOWN
+		},
+		tx_gsup(Socket, Resp)
    end,
    {noreply, State};
diff --git a/src/ue_fsm.erl b/src/ue_fsm.erl
index f6b2b7e..c0b8872 100644
--- a/src/ue_fsm.erl
+++ b/src/ue_fsm.erl
@@ -50,19 +50,39 @@
auth_request(Pid) ->
         lager:info("ue_fsm auth_request~n", []),
-        gen_statem:cast(Pid, auth_request).
+        try
+                gen_statem:call(Pid, auth_request)
+        catch
+        exit:Err ->
+                {error, Err}
+        end.
lu_request(Pid) ->
         lager:info("ue_fsm lu_request~n", []),
-        gen_statem:cast(Pid, lu_request).
+        try
+                gen_statem:call(Pid, lu_request)
+        catch
+        exit:Err ->
+                {error, Err}
+        end.
tunnel_request(Pid) ->
         lager:info("ue_fsm tunnel_request~n", []),
-        gen_statem:cast(Pid, tunnel_request).
+        try
+        gen_statem:call(Pid, tunnel_request)
+        catch
+        exit:Err ->
+                {error, Err}
+        end.
received_gtpc_create_session_response(Pid, Msg) ->
         lager:info("ue_fsm received_gtpc_create_session_response ~p~n", [Msg]),
-        gen_statem:cast(Pid, {received_gtpc_create_session_response, Msg}).
+        try
+        gen_statem:call(Pid, {received_gtpc_create_session_response, Msg})
+        catch
+        exit:Err ->
+                {error, Err}
+        end.
init(Imsi) ->
         lager:info("ue_fsm init(~p)~n", [Imsi]),
@@ -76,38 +96,42 @@
         lager:info("terminating ~p with reason ~p state=~p, ~p~n", [?MODULE, Reason, State, Data]),
         ok.
-state_new(cast, auth_request, Data) ->
+state_new({call, From}, auth_request, Data) ->
         lager:info("ue_fsm state_new event=auth_request, ~p~n", [Data]),
         Auth = auth_handler:auth_request(Data#ue_fsm_data.imsi),
         gsup_server:auth_response(Data#ue_fsm_data.imsi, Auth),
         case Auth of
                 {ok, _} ->
-                        {next_state, state_authenticated, Data};
+                        {next_state, state_authenticated, Data, [{reply,From,ok}]};
    	{error, Err} ->
-                        {stop, Err, Data}
+                        {stop_and_reply, Err, Data, [{reply,From,{error,Err}}]}
    end.
-state_authenticated(cast, lu_request, Data) ->
+state_authenticated({call, From}, lu_request, Data) ->
         lager:info("ue_fsm state_authenticated event=lu_request, ~p~n", [Data]),
         Result = epdg_diameter_swx:server_assignment_request(Data#ue_fsm_data.imsi, 1, "internet"),
         gsup_server:lu_response(Data#ue_fsm_data.imsi, Result),
         case Result of
                 {ok, _} ->
-                        {keep_state, Data};
+                        {keep_state, Data, [{reply,From,ok}]};
                 {error, Err} ->
-                        {stop, Err, Data}
+                        {stop, Err, Data, [{reply,From,{error,Err}}]}
         end;
-state_authenticated(cast, tunnel_request, Data) ->
+state_authenticated({call, From}, tunnel_request, Data) ->
         lager:info("ue_fsm state_authenticated event=tunnel_request, ~p~n", [Data]),
         epdg_gtpc_s2b:create_session_req(Data#ue_fsm_data.imsi),
-        {keep_state, Data};
+        {keep_state, Data, [{reply,From,ok}]};
-state_authenticated(cast, {received_gtpc_create_session_response, Result}, Data) ->
+state_authenticated({call, From}, {received_gtpc_create_session_response, Result}, Data) ->
         lager:info("ue_fsm state_authenticated event=received_gtpc_create_session_response, ~p~n", [Data]),
         gsup_server:tunnel_response(Data#ue_fsm_data.imsi, Result),
-        {keep_state, Data};
+        {keep_state, Data, [{reply,From,ok}]};
+
+state_authenticated({call, From}, _Whatever, Data) ->
+        lager:error("ue_fsm state_authenticated: Unexpected call event, ~p~n", [Data]),
+        {keep_state, Data, [{reply,From,ok}]};
state_authenticated(cast, _Whatever, Data) ->
-        lager:info("ue_fsm state_authenticated event=auth_request, ~p~n", [Data]),
+        lager:error("ue_fsm state_authenticated: Unexpected cast event, ~p~n", [Data]),
         {keep_state, Data}.
\ No newline at end of file
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Gerrit-Project: erlang/osmo-epdg
Gerrit-Branch: master
Gerrit-Change-Id: I235d3c8fb3a863d288b5433c39e0da65f747936b
Gerrit-Change-Number: 35675
Gerrit-PatchSet: 1
Gerrit-Owner: pespin pespin@sysmocom.de
Gerrit-MessageType: newchange



    