%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2018-2018. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
-module(tls_sender).
-behaviour(gen_statem).
-include("ssl_internal.hrl").
-include("ssl_alert.hrl").
-include("ssl_handshake.hrl").
%% API
-export([start/0, initialize/2, send_data/2, send_alert/2, renegotiate/1,
update_connection_state/3]).
%% gen_statem callbacks
-export([callback_mode/0, init/1, terminate/3, code_change/4]).
-export([init/3, connection/3, handshake/3]).
-define(SERVER, ?MODULE).
-record(data, {connection_pid,
connection_states = #{},
socket,
socket_options,
protocol_cb,
transport_cb,
negotiated_version,
renegotiate_at,
connection_monitor
}).
%%%===================================================================
%%% API
%%%===================================================================
-spec start() -> {ok, Pid :: pid()} |
ignore |
{error, Error :: term()}.
start() ->
gen_statem:start(?MODULE, [], []).
initialize(Pid, InitMsg) ->
gen_statem:call(Pid, {self(), InitMsg}).
send_data(Pid, AppData) ->
%% Needs error handling for external API
call(Pid, {application_data, AppData}).
send_alert(Pid, Alert) ->
gen_statem:cast(Pid, Alert).
%%--------------------------------------------------------------------
-spec renegotiate(pid()) -> {ok, WriteState::map()} | {error, closed}.
%% Description: So TLS connection process can synchronize the
%% encryption state to be used when handshaking.
%%--------------------------------------------------------------------
renegotiate(Pid) ->
%% Needs error handling for external API
call(Pid, renegotiate).
%%--------------------------------------------------------------------
-spec update_connection_state(pid(), WriteState::map(), tls_record:tls_version()) -> ok.
%% Description: So TLS connection process can synchronize the
%% encryption state to be used when sending application data.
%%--------------------------------------------------------------------
update_connection_state(Pid, NewState, Version) ->
gen_statem:cast(Pid, {new_write, NewState, Version}).
%%%===================================================================
%%% gen_statem callbacks
%%%===================================================================
%%--------------------------------------------------------------------
-spec callback_mode() -> gen_statem:callback_mode_result().
%%--------------------------------------------------------------------
callback_mode() ->
state_functions.
%%--------------------------------------------------------------------
-spec init(Args :: term()) ->
gen_statem:init_result(atom()).
%%--------------------------------------------------------------------
init(_) ->
{ok, init, #data{}}.
%%--------------------------------------------------------------------
-spec init(gen_statem:event_type(),
Msg :: term(),
StateData :: term()) ->
gen_statem:event_handler_result(atom()).
%%--------------------------------------------------------------------
init({call, From}, {Pid, #{current_write := WriteState,
socket := Socket,
socket_options := SockOpts,
protocol_cb := Connection,
transport_cb := Transport,
negotiated_version := Version,
renegotiate_at := RenegotiateAt}},
#data{connection_states = ConnectionStates} = StateData0) ->
Monitor = erlang:monitor(process, Pid),
StateData =
StateData0#data{connection_pid = Pid,
connection_monitor = Monitor,
connection_states =
ConnectionStates#{current_write => WriteState},
socket = Socket,
socket_options = SockOpts,
protocol_cb = Connection,
transport_cb = Transport,
negotiated_version = Version,
renegotiate_at = RenegotiateAt},
{next_state, handshake, StateData, [{reply, From, ok}]};
init(info, Msg, StateData) ->
handle_info(Msg, ?FUNCTION_NAME, StateData).
%%--------------------------------------------------------------------
-spec connection(gen_statem:event_type(),
Msg :: term(),
StateData :: term()) ->
gen_statem:event_handler_result(atom()).
%%--------------------------------------------------------------------
connection({call, From}, renegotiate,
#data{connection_states = #{current_write := Write}} = StateData) ->
{next_state, handshake, StateData, [{reply, From, {ok, Write}}]};
connection({call, From}, {application_data, AppData},
#data{socket_options = SockOpts} = StateData) ->
case encode_packet(AppData, SockOpts) of
{error, _} = Error ->
{next_state, ?FUNCTION_NAME, StateData, [{reply, From, Error}]};
Data ->
send_application_data(Data, From, ?FUNCTION_NAME, StateData)
end;
connection(cast, #alert{} = Alert, StateData0) ->
StateData = send_tls_alert(Alert, StateData0),
{next_state, ?FUNCTION_NAME, StateData};
connection(cast, {new_write, WritesState, Version},
#data{connection_states = ConnectionStates0} = StateData) ->
{next_state, connection,
StateData#data{connection_states =
ConnectionStates0#{current_write => WritesState},
negotiated_version = Version}};
connection(info, Msg, StateData) ->
handle_info(Msg, ?FUNCTION_NAME, StateData).
%%--------------------------------------------------------------------
-spec handshake(gen_statem:event_type(),
Msg :: term(),
StateData :: term()) ->
gen_statem:event_handler_result(atom()).
%%--------------------------------------------------------------------
handshake({call, _}, _, _) ->
{keep_state_and_data, [postpone]};
handshake(cast, {new_write, WritesState, Version},
#data{connection_states = ConnectionStates0} = StateData) ->
{next_state, connection,
StateData#data{connection_states =
ConnectionStates0#{current_write => WritesState},
negotiated_version = Version}};
handshake(info, Msg, StateData) ->
handle_info(Msg, ?FUNCTION_NAME, StateData).
%%--------------------------------------------------------------------
-spec terminate(Reason :: term(), State :: term(), Data :: term()) ->
any().
%%--------------------------------------------------------------------
terminate(_Reason, _State, _Data) ->
void.
%%--------------------------------------------------------------------
-spec code_change(
OldVsn :: term() | {down,term()},
State :: term(), Data :: term(), Extra :: term()) ->
{ok, NewState :: term(), NewData :: term()} |
(Reason :: term()).
%% Convert process state when code is changed
%%--------------------------------------------------------------------
code_change(_OldVsn, State, Data, _Extra) ->
{ok, State, Data}.
%%%===================================================================
%%% Internal functions
%%%===================================================================
handle_info({'DOWN', Monitor, _, _, Reason}, _,
#data{connection_monitor = Monitor} = StateData) ->
{stop, {shutdown, Reason}, StateData};
handle_info(_,_,_) ->
{keep_state_and_data}.
send_tls_alert(Alert, #data{negotiated_version = Version,
socket = Socket,
protocol_cb = Connection,
transport_cb = Transport,
connection_states = ConnectionStates0} = StateData0) ->
{BinMsg, ConnectionStates} =
Connection:encode_alert(Alert, Version, ConnectionStates0),
Connection:send(Transport, Socket, BinMsg),
StateData0#data{connection_states = ConnectionStates}.
send_application_data(Data, {FromPid, _} = From, StateName,
#data{connection_pid = Pid,
socket = Socket,
negotiated_version = Version,
protocol_cb = Connection,
transport_cb = Transport,
connection_states = ConnectionStates0,
renegotiate_at = RenegotiateAt} = StateData0) ->
case time_to_renegotiate(Data, ConnectionStates0, RenegotiateAt) of
true ->
ssl_connection:internal_renegotiation(Pid, ConnectionStates0),
{next_state, handshake, StateData0,
[{next_event, {call, From}, {application_data, Data}}]};
false ->
{Msgs, ConnectionStates} =
Connection:encode_data(Data, Version, ConnectionStates0),
StateData = StateData0#data{connection_states = ConnectionStates},
case Connection:send(Transport, Socket, Msgs) of
ok when FromPid =:= Pid ->
{next_state, StateName, StateData, []};
Error when FromPid =:= Pid ->
ssl_connection:stop({shutdown, Error}, StateData);
ok ->
{next_state, StateName, StateData, [{reply, From, ok}]};
Result ->
{next_state, StateName, StateData, [{reply, From, Result}]}
end
end.
encode_packet(Data, #socket_options{packet=Packet}) ->
case Packet of
1 -> encode_size_packet(Data, 8, (1 bsl 8) - 1);
2 -> encode_size_packet(Data, 16, (1 bsl 16) - 1);
4 -> encode_size_packet(Data, 32, (1 bsl 32) - 1);
_ -> Data
end.
encode_size_packet(Bin, Size, Max) ->
Len = erlang:byte_size(Bin),
case Len > Max of
true ->
{error, {badarg, {packet_to_large, Len, Max}}};
false ->
<<Len:Size, Bin/binary>>
end.
time_to_renegotiate(_Data,
#{current_write := #{sequence_number := Num}},
RenegotiateAt) ->
%% We could do test:
%% is_time_to_renegotiate((erlang:byte_size(_Data) div
%% ?MAX_PLAIN_TEXT_LENGTH) + 1, RenegotiateAt), but we chose to
%% have a some what lower renegotiateAt and a much cheaper test
is_time_to_renegotiate(Num, RenegotiateAt).
is_time_to_renegotiate(N, M) when N < M->
false;
is_time_to_renegotiate(_,_) ->
true.
call(FsmPid, Event) ->
try gen_statem:call(FsmPid, Event)
catch
exit:{noproc, _} ->
{error, closed};
exit:{normal, _} ->
{error, closed};
exit:{{shutdown, _},_} ->
{error, closed}
end.
