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Diffstat (limited to 'lib/ssl/src/dtls_connection.erl')
| -rw-r--r-- | lib/ssl/src/dtls_connection.erl | 636 |
1 files changed, 626 insertions, 10 deletions
diff --git a/lib/ssl/src/dtls_connection.erl b/lib/ssl/src/dtls_connection.erl index ac2ee0d09f..b8be686b99 100644 --- a/lib/ssl/src/dtls_connection.erl +++ b/lib/ssl/src/dtls_connection.erl @@ -1,19 +1,635 @@ %% %% %CopyrightBegin% %% -%% Copyright Ericsson AB 2013-2013. All Rights Reserved. +%% Copyright Ericsson AB 2013-2015. All Rights Reserved. %% -%% The contents of this file are subject to the Erlang Public License, -%% Version 1.1, (the "License"); you may not use this file except in -%% compliance with the License. You should have received a copy of the -%% Erlang Public License along with this software. If not, it can be -%% retrieved online at http://www.erlang.org/. +%% 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 %% -%% Software distributed under the License is distributed on an "AS IS" -%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See -%% the License for the specific language governing rights and limitations -%% under the License. +%% 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(dtls_connection). + +%% Internal application API + +-behaviour(gen_statem). + +-include("dtls_connection.hrl"). +-include("dtls_handshake.hrl"). +-include("ssl_alert.hrl"). +-include("dtls_record.hrl"). +-include("ssl_cipher.hrl"). +-include("ssl_api.hrl"). +-include("ssl_internal.hrl"). +-include("ssl_srp.hrl"). +-include_lib("public_key/include/public_key.hrl"). + +%% Internal application API + +%% Setup +-export([start_fsm/8, start_link/7, init/1]). + +%% State transition handling +-export([next_record/1, next_event/3]). + +%% Handshake handling +-export([%%renegotiate/2, + send_handshake/2, queue_handshake/2, queue_change_cipher/2]). + +%% Alert and close handling +-export([%%send_alert/2, handle_own_alert/4, handle_close_alert/3, + handle_normal_shutdown/3 %%, close/5 + %%alert_user/6, alert_user/9 + ]). + +%% Data handling + +-export([%%write_application_data/3, + read_application_data/2, + passive_receive/2, next_record_if_active/1%, + %%handle_common_event/4, + %handle_packet/3 + ]). + +%% gen_statem state functions +-export([init/3, error/3, downgrade/3, %% Initiation and take down states + hello/3, certify/3, cipher/3, abbreviated/3, %% Handshake states + connection/3]). +%% gen_statem callbacks +-export([terminate/3, code_change/4, format_status/2]). + +-define(GEN_STATEM_CB_MODE, state_functions). + +%%==================================================================== +%% Internal application API +%%==================================================================== +start_fsm(Role, Host, Port, Socket, {#ssl_options{erl_dist = false},_, Tracker} = Opts, + User, {CbModule, _,_, _} = CbInfo, + Timeout) -> + try + {ok, Pid} = dtls_connection_sup:start_child([Role, Host, Port, Socket, + Opts, User, CbInfo]), + {ok, SslSocket} = ssl_connection:socket_control(?MODULE, Socket, Pid, CbModule, Tracker), + ok = ssl_connection:handshake(SslSocket, Timeout), + {ok, SslSocket} + catch + error:{badmatch, {error, _} = Error} -> + Error + end; + +start_fsm(Role, Host, Port, Socket, {#ssl_options{erl_dist = true},_, Tracker} = Opts, + User, {CbModule, _,_, _} = CbInfo, + Timeout) -> + try + {ok, Pid} = dtls_connection_sup:start_child_dist([Role, Host, Port, Socket, + Opts, User, CbInfo]), + {ok, SslSocket} = ssl_connection:socket_control(?MODULE, Socket, Pid, CbModule, Tracker), + ok = ssl_connection:handshake(SslSocket, Timeout), + {ok, SslSocket} + catch + error:{badmatch, {error, _} = Error} -> + Error + end. + +send_handshake(Handshake, State) -> + send_handshake_flight(queue_handshake(Handshake, State)). + +queue_flight_buffer(Msg, #state{negotiated_version = Version, + connection_states = #connection_states{ + current_write = + #connection_state{epoch = Epoch}}, + flight_buffer = Flight} = State) -> + State#state{flight_buffer = Flight ++ [{Version, Epoch, Msg}]}. + +queue_handshake(Handshake, #state{negotiated_version = Version, + tls_handshake_history = Hist0, + connection_states = ConnectionStates0} = State0) -> + {Frag, ConnectionStates, Hist} = + encode_handshake(Handshake, Version, ConnectionStates0, Hist0), + queue_flight_buffer(Frag, State0#state{connection_states = ConnectionStates, + tls_handshake_history = Hist}). + +send_handshake_flight(#state{socket = Socket, + transport_cb = Transport, + flight_buffer = Flight, + connection_states = ConnectionStates0} = State0) -> + + {Encoded, ConnectionStates} = + encode_handshake_flight(Flight, ConnectionStates0), + + Transport:send(Socket, Encoded), + State0#state{flight_buffer = [], connection_states = ConnectionStates}. + +queue_change_cipher(Msg, State) -> + queue_flight_buffer(Msg, State). + +send_alert(Alert, #state{negotiated_version = Version, + socket = Socket, + transport_cb = Transport, + connection_states = ConnectionStates0} = State0) -> + {BinMsg, ConnectionStates} = + ssl_alert:encode(Alert, Version, ConnectionStates0), + Transport:send(Socket, BinMsg), + State0#state{connection_states = ConnectionStates}. + +%%==================================================================== +%% tls_connection_sup API +%%==================================================================== + +%%-------------------------------------------------------------------- +-spec start_link(atom(), host(), inet:port_number(), port(), list(), pid(), tuple()) -> + {ok, pid()} | ignore | {error, reason()}. +%% +%% Description: Creates a gen_fsm process which calls Module:init/1 to +%% initialize. To ensure a synchronized start-up procedure, this function +%% does not return until Module:init/1 has returned. +%%-------------------------------------------------------------------- +start_link(Role, Host, Port, Socket, Options, User, CbInfo) -> + {ok, proc_lib:spawn_link(?MODULE, init, [[Role, Host, Port, Socket, Options, User, CbInfo]])}. + +init([Role, Host, Port, Socket, Options, User, CbInfo]) -> + process_flag(trap_exit, true), + State0 = initial_state(Role, Host, Port, Socket, Options, User, CbInfo), + try + State = ssl_connection:ssl_config(State0#state.ssl_options, Role, State0), + gen_statem:enter_loop(?MODULE, [], ?GEN_STATEM_CB_MODE, init, State) + catch + throw:Error -> + gen_statem:enter_loop(?MODULE, [], ?GEN_STATEM_CB_MODE, error, {Error,State0}) + end. + +%%-------------------------------------------------------------------- +%% State functionsconnection/2 +%%-------------------------------------------------------------------- + +init({call, From}, {start, Timeout}, + #state{host = Host, port = Port, role = client, + ssl_options = SslOpts, + session = #session{own_certificate = Cert} = Session0, + transport_cb = Transport, socket = Socket, + connection_states = ConnectionStates0, + renegotiation = {Renegotiation, _}, + session_cache = Cache, + session_cache_cb = CacheCb + } = State0) -> + Timer = ssl_connection:start_or_recv_cancel_timer(Timeout, From), + Hello = dtls_handshake:client_hello(Host, Port, ConnectionStates0, SslOpts, + Cache, CacheCb, Renegotiation, Cert), + + Version = Hello#client_hello.client_version, + HelloVersion = dtls_record:lowest_protocol_version(SslOpts#ssl_options.versions), + Handshake0 = ssl_handshake:init_handshake_history(), + {BinMsg, ConnectionStates, Handshake} = + encode_handshake(Hello, HelloVersion, ConnectionStates0, Handshake0), + Transport:send(Socket, BinMsg), + State1 = State0#state{connection_states = ConnectionStates, + negotiated_version = Version, %% Requested version + session = + Session0#session{session_id = Hello#client_hello.session_id}, + tls_handshake_history = Handshake, + start_or_recv_from = From, + timer = Timer}, + {Record, State} = next_record(State1), + next_event(hello, Record, State); +init(Type, Event, State) -> + ssl_connection:init(Type, Event, State, ?MODULE). + +error({call, From}, {start, _Timeout}, {Error, State}) -> + {stop_and_reply, normal, {reply, From, {error, Error}}, State}; +error({call, From}, Msg, State) -> + handle_call(Msg, From, error, State); +error(_, _, _) -> + {keep_state_and_data, [postpone]}. + +%%-------------------------------------------------------------------- +-spec hello(gen_statem:event_type(), + #hello_request{} | #client_hello{} | #server_hello{} | term(), + #state{}) -> + gen_statem:state_function_result(). +%%-------------------------------------------------------------------- +hello(internal, #client_hello{client_version = ClientVersion, + extensions = #hello_extensions{ec_point_formats = EcPointFormats, + elliptic_curves = EllipticCurves}} = Hello, + State = #state{connection_states = ConnectionStates0, + port = Port, session = #session{own_certificate = Cert} = Session0, + renegotiation = {Renegotiation, _}, + session_cache = Cache, + session_cache_cb = CacheCb, + negotiated_protocol = CurrentProtocol, + key_algorithm = KeyExAlg, + ssl_options = SslOpts}) -> + + case dtls_handshake:hello(Hello, SslOpts, {Port, Session0, Cache, CacheCb, + ConnectionStates0, Cert, KeyExAlg}, Renegotiation) of + #alert{} = Alert -> + handle_own_alert(Alert, ClientVersion, hello, State); + {Version, {Type, Session}, + ConnectionStates, Protocol0, ServerHelloExt, HashSign} -> + Protocol = case Protocol0 of + undefined -> CurrentProtocol; + _ -> Protocol0 + end, + + ssl_connection:hello(internal, {common_client_hello, Type, ServerHelloExt}, + State#state{connection_states = ConnectionStates, + negotiated_version = Version, + hashsign_algorithm = HashSign, + session = Session, + client_ecc = {EllipticCurves, EcPointFormats}, + negotiated_protocol = Protocol}, ?MODULE) + end; +hello(internal, #server_hello{} = Hello, + #state{connection_states = ConnectionStates0, + negotiated_version = ReqVersion, + role = client, + renegotiation = {Renegotiation, _}, + ssl_options = SslOptions} = State) -> + case dtls_handshake:hello(Hello, SslOptions, ConnectionStates0, Renegotiation) of + #alert{} = Alert -> + handle_own_alert(Alert, ReqVersion, hello, State); + {Version, NewId, ConnectionStates, ProtoExt, Protocol} -> + ssl_connection:handle_session(Hello, + Version, NewId, ConnectionStates, ProtoExt, Protocol, State) + end; +hello(info, Event, State) -> + handle_info(Event, hello, State); + +hello(Type, Event, State) -> + ssl_connection:hello(Type, Event, State, ?MODULE). + +abbreviated(info, Event, State) -> + handle_info(Event, abbreviated, State); +abbreviated(Type, Event, State) -> + ssl_connection:abbreviated(Type, Event, State, ?MODULE). + +certify(info, Event, State) -> + handle_info(Event, certify, State); +certify(Type, Event, State) -> + ssl_connection:certify(Type, Event, State, ?MODULE). + +cipher(info, Event, State) -> + handle_info(Event, cipher, State); +cipher(Type, Event, State) -> + ssl_connection:cipher(Type, Event, State, ?MODULE). + +connection(info, Event, State) -> + handle_info(Event, connection, State); +connection(internal, #hello_request{}, #state{host = Host, port = Port, + session = #session{own_certificate = Cert} = Session0, + session_cache = Cache, session_cache_cb = CacheCb, + ssl_options = SslOpts, + connection_states = ConnectionStates0, + renegotiation = {Renegotiation, _}} = State0) -> + Hello = dtls_handshake:client_hello(Host, Port, ConnectionStates0, SslOpts, + Cache, CacheCb, Renegotiation, Cert), + State1 = send_handshake(Hello, State0), + {Record, State} = + next_record( + State1#state{session = Session0#session{session_id + = Hello#client_hello.session_id}}), + next_event(hello, Record, State); + +connection(internal, #client_hello{} = Hello, #state{role = server, allow_renegotiate = true} = State) -> + %% Mitigate Computational DoS attack + %% http://www.educatedguesswork.org/2011/10/ssltls_and_computational_dos.html + %% http://www.thc.org/thc-ssl-dos/ Rather than disabling client + %% initiated renegotiation we will disallow many client initiated + %% renegotiations immediately after each other. + erlang:send_after(?WAIT_TO_ALLOW_RENEGOTIATION, self(), allow_renegotiate), + {next_state, hello, State#state{allow_renegotiate = false}, [{next_event, internal, Hello}]}; + + +connection(internal, #client_hello{}, #state{role = server, allow_renegotiate = false} = State0) -> + Alert = ?ALERT_REC(?WARNING, ?NO_RENEGOTIATION), + State1 = send_alert(Alert, State0), + {Record, State} = ssl_connection:prepare_connection(State1, ?MODULE), + next_event(connection, Record, State); + +connection(Type, Event, State) -> + ssl_connection:connection(Type, Event, State, ?MODULE). + +downgrade(Type, Event, State) -> + ssl_connection:downgrade(Type, Event, State, ?MODULE). + + +%%-------------------------------------------------------------------- +%% Description: This function is called by a gen_fsm when it receives any +%% other message than a synchronous or asynchronous event +%% (or a system message). +%%-------------------------------------------------------------------- + +%% raw data from socket, unpack records +handle_info({Protocol, _, Data}, StateName, + #state{data_tag = Protocol} = State0) -> + case next_tls_record(Data, State0) of + {Record, State} -> + next_event(StateName, Record, State); + #alert{} = Alert -> + handle_normal_shutdown(Alert, StateName, State0), + {stop, {shutdown, own_alert}} + end; +handle_info({CloseTag, Socket}, StateName, + #state{socket = Socket, close_tag = CloseTag, + negotiated_version = Version} = State) -> + %% Note that as of DTLS 1.2 (TLS 1.1), + %% failure to properly close a connection no longer requires that a + %% session not be resumed. This is a change from DTLS 1.0 to conform + %% with widespread implementation practice. + case Version of + {254, N} when N =< 253 -> + ok; + _ -> + %% As invalidate_sessions here causes performance issues, + %% we will conform to the widespread implementation + %% practice and go aginst the spec + %%invalidate_session(Role, Host, Port, Session) + ok + end, + handle_normal_shutdown(?ALERT_REC(?FATAL, ?CLOSE_NOTIFY), StateName, State), + {stop, {shutdown, transport_closed}}; +handle_info(Msg, StateName, State) -> + ssl_connection:handle_info(Msg, StateName, State). + +handle_call(Event, From, StateName, State) -> + ssl_connection:handle_call(Event, From, StateName, State, ?MODULE). + +%%-------------------------------------------------------------------- +%% Description:This function is called by a gen_fsm when it is about +%% to terminate. It should be the opposite of Module:init/1 and do any +%% necessary cleaning up. When it returns, the gen_fsm terminates with +%% Reason. The return value is ignored. +%%-------------------------------------------------------------------- +terminate(Reason, StateName, State) -> + ssl_connection:terminate(Reason, StateName, State). + +%%-------------------------------------------------------------------- +%% code_change(OldVsn, StateName, State, Extra) -> {ok, StateName, NewState} +%% Description: Convert process state when code is changed +%%-------------------------------------------------------------------- +code_change(_OldVsn, StateName, State, _Extra) -> + {?GEN_STATEM_CB_MODE, StateName, State}. + +format_status(Type, Data) -> + ssl_connection:format_status(Type, Data). + +%%-------------------------------------------------------------------- +%%% Internal functions +%%-------------------------------------------------------------------- +encode_handshake(Handshake, Version, ConnectionStates0, Hist0) -> + {Seq, ConnectionStates} = sequence(ConnectionStates0), + {EncHandshake, Frag} = dtls_handshake:encode_handshake(Handshake, Version, Seq), + Hist = ssl_handshake:update_handshake_history(Hist0, EncHandshake), + {Frag, ConnectionStates, Hist}. + +encode_change_cipher(#change_cipher_spec{}, Version, ConnectionStates) -> + dtls_record:encode_change_cipher_spec(Version, ConnectionStates). + +encode_handshake_flight(Flight, ConnectionStates) -> + MSS = 1400, + encode_handshake_records(Flight, ConnectionStates, MSS, init_pack_records()). + +encode_handshake_records([], CS, _MSS, Recs) -> + {finish_pack_records(Recs), CS}; + +encode_handshake_records([{Version, _Epoch, Frag = #change_cipher_spec{}}|Tail], ConnectionStates0, MSS, Recs0) -> + {Encoded, ConnectionStates} = + encode_change_cipher(Frag, Version, ConnectionStates0), + Recs = append_pack_records([Encoded], MSS, Recs0), + encode_handshake_records(Tail, ConnectionStates, MSS, Recs); + +encode_handshake_records([{Version, Epoch, {MsgType, MsgSeq, Bin}}|Tail], CS0, MSS, Recs0 = {Buf0, _}) -> + Space = MSS - iolist_size(Buf0), + Len = byte_size(Bin), + {Encoded, CS} = + encode_handshake_record(Version, Epoch, Space, MsgType, MsgSeq, Len, Bin, 0, MSS, [], CS0), + Recs = append_pack_records(Encoded, MSS, Recs0), + encode_handshake_records(Tail, CS, MSS, Recs). + +%% TODO: move to dtls_handshake???? +encode_handshake_record(_Version, _Epoch, _Space, _MsgType, _MsgSeq, _Len, <<>>, _Offset, _MRS, Encoded, CS) + when length(Encoded) > 0 -> + %% make sure we encode at least one segment (for empty messages like Server Hello Done + {lists:reverse(Encoded), CS}; + +encode_handshake_record(Version, Epoch, Space, MsgType, MsgSeq, Len, Bin, + Offset, MRS, Encoded0, CS0) -> + MaxFragmentLen = Space - 25, + case Bin of + <<BinFragment:MaxFragmentLen/bytes, Rest/binary>> -> + ok; + _ -> + BinFragment = Bin, + Rest = <<>> + end, + FragLength = byte_size(BinFragment), + Frag = [MsgType, ?uint24(Len), ?uint16(MsgSeq), ?uint24(Offset), ?uint24(FragLength), BinFragment], + %% TODO Real solution, now avoid dialyzer error {Encoded, CS} = ssl_record:encode_handshake({Epoch, Frag}, Version, CS0), + {Encoded, CS} = ssl_record:encode_handshake(Frag, Version, CS0), + encode_handshake_record(Version, Epoch, MRS, MsgType, MsgSeq, Len, Rest, Offset + FragLength, MRS, [Encoded|Encoded0], CS). + +init_pack_records() -> + {[], []}. + +append_pack_records([], MSS, Recs = {Buf0, Acc0}) -> + Remaining = MSS - iolist_size(Buf0), + if Remaining < 12 -> + {[], [lists:reverse(Buf0)|Acc0]}; + true -> + Recs + end; +append_pack_records([Head|Tail], MSS, {Buf0, Acc0}) -> + TotLen = iolist_size(Buf0) + iolist_size(Head), + if TotLen > MSS -> + append_pack_records(Tail, MSS, {[Head], [lists:reverse(Buf0)|Acc0]}); + true -> + append_pack_records(Tail, MSS, {[Head|Buf0], Acc0}) + end. + +finish_pack_records({[], Acc}) -> + lists:reverse(Acc); +finish_pack_records({Buf, Acc}) -> + lists:reverse([lists:reverse(Buf)|Acc]). + +%% decode_alerts(Bin) -> +%% ssl_alert:decode(Bin). + +initial_state(Role, Host, Port, Socket, {SSLOptions, SocketOptions}, User, + {CbModule, DataTag, CloseTag, ErrorTag}) -> + #ssl_options{beast_mitigation = BeastMitigation} = SSLOptions, + ConnectionStates = ssl_record:init_connection_states(Role, BeastMitigation), + + SessionCacheCb = case application:get_env(ssl, session_cb) of + {ok, Cb} when is_atom(Cb) -> + Cb; + _ -> + ssl_session_cache + end, + + Monitor = erlang:monitor(process, User), + + #state{socket_options = SocketOptions, + %% We do not want to save the password in the state so that + %% could be written in the clear into error logs. + ssl_options = SSLOptions#ssl_options{password = undefined}, + session = #session{is_resumable = new}, + transport_cb = CbModule, + data_tag = DataTag, + close_tag = CloseTag, + error_tag = ErrorTag, + role = Role, + host = Host, + port = Port, + socket = Socket, + connection_states = ConnectionStates, + protocol_buffers = #protocol_buffers{}, + user_application = {Monitor, User}, + user_data_buffer = <<>>, + session_cache_cb = SessionCacheCb, + renegotiation = {false, first}, + allow_renegotiate = SSLOptions#ssl_options.client_renegotiation, + start_or_recv_from = undefined, + protocol_cb = ?MODULE + }. + +next_tls_record(Data, #state{protocol_buffers = #protocol_buffers{ + dtls_record_buffer = Buf0, + dtls_cipher_texts = CT0} = Buffers} = State0) -> + case dtls_record:get_dtls_records(Data, Buf0) of + {Records, Buf1} -> + CT1 = CT0 ++ Records, + next_record(State0#state{protocol_buffers = + Buffers#protocol_buffers{dtls_record_buffer = Buf1, + dtls_cipher_texts = CT1}}); + + #alert{} = Alert -> + Alert + end. + +next_record(#state{%%flight = #flight{state = finished}, + protocol_buffers = + #protocol_buffers{dtls_packets = [], dtls_cipher_texts = [CT | Rest]} + = Buffers, + connection_states = ConnStates0} = State) -> + case dtls_record:decode_cipher_text(CT, ConnStates0) of + {Plain, ConnStates} -> + {Plain, State#state{protocol_buffers = + Buffers#protocol_buffers{dtls_cipher_texts = Rest}, + connection_states = ConnStates}}; + #alert{} = Alert -> + {Alert, State} + end; +next_record(#state{socket = Socket, + transport_cb = Transport} = State) -> %% when FlightState =/= finished + ssl_socket:setopts(Transport, Socket, [{active,once}]), + {no_record, State}; +next_record(State) -> + {no_record, State}. + +next_record_if_active(State = + #state{socket_options = + #socket_options{active = false}}) -> + {no_record ,State}; + +next_record_if_active(State) -> + next_record(State). + +passive_receive(State0 = #state{user_data_buffer = Buffer}, StateName) -> + case Buffer of + <<>> -> + {Record, State} = next_record(State0), + next_event(StateName, Record, State); + _ -> + {Record, State} = read_application_data(<<>>, State0), + next_event(StateName, Record, State) + end. + +next_event(StateName, Record, State) -> + next_event(StateName, Record, State, []). + +next_event(connection = StateName, no_record, State0, Actions) -> + case next_record_if_active(State0) of + {no_record, State} -> + ssl_connection:hibernate_after(StateName, State, Actions); + {#ssl_tls{} = Record, State} -> + {next_state, StateName, State, [{next_event, internal, {dtls_record, Record}} | Actions]}; + {#alert{} = Alert, State} -> + {next_state, StateName, State, [{next_event, internal, Alert} | Actions]} + end; +next_event(StateName, Record, State, Actions) -> + case Record of + no_record -> + {next_state, StateName, State, Actions}; + #ssl_tls{} = Record -> + {next_state, StateName, State, [{next_event, internal, {dtls_record, Record}} | Actions]}; + #alert{} = Alert -> + {next_state, StateName, State, [{next_event, internal, Alert} | Actions]} + end. + +read_application_data(_,State) -> + {#ssl_tls{fragment = <<"place holder">>}, State}. + +handle_own_alert(_,_,_, State) -> %% Place holder + {stop, {shutdown, own_alert}, State}. + +handle_normal_shutdown(_, _, _State) -> %% Place holder + ok. + +%% TODO This generates dialyzer warnings, has to be handled differently. +%% handle_packet(Address, Port, Packet) -> +%% try dtls_record:get_dtls_records(Packet, <<>>) of +%% %% expect client hello +%% {[#ssl_tls{type = ?HANDSHAKE, version = {254, _}} = Record], <<>>} -> +%% handle_dtls_client_hello(Address, Port, Record); +%% _Other -> +%% {error, not_dtls} +%% catch +%% _Class:_Error -> +%% {error, not_dtls} +%% end. + +%% handle_dtls_client_hello(Address, Port, +%% #ssl_tls{epoch = Epoch, sequence_number = Seq, +%% version = Version} = Record) -> +%% {[{Hello, _}], _} = +%% dtls_handshake:get_dtls_handshake(Record, +%% dtls_handshake:dtls_handshake_new_flight(undefined)), +%% #client_hello{client_version = {Major, Minor}, +%% random = Random, +%% session_id = SessionId, +%% cipher_suites = CipherSuites, +%% compression_methods = CompressionMethods} = Hello, +%% CookieData = [address_to_bin(Address, Port), +%% <<?BYTE(Major), ?BYTE(Minor)>>, +%% Random, SessionId, CipherSuites, CompressionMethods], +%% Cookie = crypto:hmac(sha, <<"secret">>, CookieData), + +%% case Hello of +%% #client_hello{cookie = Cookie} -> +%% accept; + +%% _ -> +%% %% generate HelloVerifyRequest +%% {RequestFragment, _} = dtls_handshake:encode_handshake( +%% dtls_handshake:hello_verify_request(Cookie), +%% Version, 0), +%% HelloVerifyRequest = +%% dtls_record:encode_tls_cipher_text(?HANDSHAKE, Version, Epoch, Seq, RequestFragment), +%% {reply, HelloVerifyRequest} +%% end. + +%% address_to_bin({A,B,C,D}, Port) -> +%% <<0:80,16#ffff:16,A,B,C,D,Port:16>>; +%% address_to_bin({A,B,C,D,E,F,G,H}, Port) -> +%% <<A:16,B:16,C:16,D:16,E:16,F:16,G:16,H:16,Port:16>>. + +sequence(#connection_states{dtls_write_msg_seq = Seq} = CS) -> + {Seq, CS#connection_states{dtls_write_msg_seq = Seq + 1}}. |