From 1e6942e97339ff39a0436834c260bf50c3d3a481 Mon Sep 17 00:00:00 2001 From: Ingela Anderton Andin Date: Tue, 20 Sep 2016 20:58:34 +0200 Subject: ssl: Implement DTLS state machine Beta DTLS, not production ready. Only very basically tested, and not everything in the SPEC is implemented and some things are hard coded that should not be, so this implementation can not be consider secure. Refactor "TLS connection state" and socket handling, to facilitate DTLS implementation. Create dtls "listner" (multiplexor) process that spawns DTLS connection process handlers. Handle DTLS fragmentation. Framework for handling retransmissions. Replay Detection is not implemented yet. Alerts currently always handled as in TLS. --- lib/ssl/src/dtls_handshake.erl | 555 ++++++++++++++++++++--------------------- 1 file changed, 273 insertions(+), 282 deletions(-) (limited to 'lib/ssl/src/dtls_handshake.erl') diff --git a/lib/ssl/src/dtls_handshake.erl b/lib/ssl/src/dtls_handshake.erl index c6535d5928..af3708ddb7 100644 --- a/lib/ssl/src/dtls_handshake.erl +++ b/lib/ssl/src/dtls_handshake.erl @@ -18,15 +18,15 @@ %% %CopyrightEnd% -module(dtls_handshake). +-include("dtls_connection.hrl"). -include("dtls_handshake.hrl"). -include("dtls_record.hrl"). -include("ssl_internal.hrl"). -include("ssl_alert.hrl"). --export([client_hello/8, client_hello/9, hello/4, - hello_verify_request/1, get_dtls_handshake/2, - dtls_handshake_new_flight/1, dtls_handshake_new_epoch/1, - encode_handshake/3]). +-export([client_hello/8, client_hello/9, cookie/4, hello/4, + hello_verify_request/2, get_dtls_handshake/3, fragment_handshake/2, + handshake_bin/2, encode_handshake/3]). -type dtls_handshake() :: #client_hello{} | #hello_verify_request{} | ssl_handshake:ssl_handshake(). @@ -62,9 +62,10 @@ client_hello(Host, Port, Cookie, ConnectionStates, Version = dtls_record:highest_protocol_version(Versions), Pending = ssl_record:pending_connection_state(ConnectionStates, read), SecParams = maps:get(security_parameters, Pending), - CipherSuites = ssl_handshake:available_suites(UserSuites, Version), + TLSVersion = dtls_v1:corresponding_tls_version(Version), + CipherSuites = ssl_handshake:available_suites(UserSuites, TLSVersion), - Extensions = ssl_handshake:client_hello_extensions(Host, dtls_v1:corresponding_tls_version(Version), CipherSuites, + Extensions = ssl_handshake:client_hello_extensions(Host, TLSVersion, CipherSuites, SslOpts, ConnectionStates, Renegotiation), Id = ssl_session:client_id({Host, Port, SslOpts}, Cache, CacheCb, OwnCert), @@ -96,72 +97,51 @@ hello(#client_hello{client_version = ClientVersion} = Hello, #ssl_options{versions = Versions} = SslOpts, Info, Renegotiation) -> Version = ssl_handshake:select_version(dtls_record, ClientVersion, Versions), - %% - %% TODO: handle Cipher Fallback - %% handle_client_hello(Version, Hello, SslOpts, Info, Renegotiation). --spec hello_verify_request(binary()) -> #hello_verify_request{}. +cookie(Key, Address, Port, #client_hello{client_version = {Major, Minor}, + random = Random, + session_id = SessionId, + cipher_suites = CipherSuites, + compression_methods = CompressionMethods}) -> + CookieData = [address_to_bin(Address, Port), + <>, + Random, SessionId, CipherSuites, CompressionMethods], + crypto:hmac(sha, Key, CookieData). + +-spec hello_verify_request(binary(), dtls_record:dtls_version()) -> #hello_verify_request{}. %% %% Description: Creates a hello verify request message sent by server to %% verify client %%-------------------------------------------------------------------- -hello_verify_request(Cookie) -> - %% TODO: DTLS Versions????? - #hello_verify_request{protocol_version = {254, 255}, cookie = Cookie}. +hello_verify_request(Cookie, Version) -> + #hello_verify_request{protocol_version = Version, cookie = Cookie}. %%-------------------------------------------------------------------- -%% %%-------------------------------------------------------------------- -encode_handshake(Handshake, Version, MsgSeq) -> +encode_handshake(Handshake, Version, Seq) -> {MsgType, Bin} = enc_handshake(Handshake, Version), Len = byte_size(Bin), - Enc = [MsgType, ?uint24(Len), ?uint16(MsgSeq), ?uint24(0), ?uint24(Len), Bin], - Frag = {MsgType, MsgSeq, Bin}, - {Enc, Frag}. + [MsgType, ?uint24(Len), ?uint16(Seq), ?uint24(0), ?uint24(Len), Bin]. -%%-------------------------------------------------------------------- --spec get_dtls_handshake(#ssl_tls{}, #dtls_hs_state{} | undefined) -> - {[dtls_handshake()], #dtls_hs_state{}} | {retransmit, #dtls_hs_state{}}. -%% -%% Description: Given a DTLS state and new data from ssl_record, collects -%% and returns it as a list of handshake messages, also returns a new -%% DTLS state -%%-------------------------------------------------------------------- -get_dtls_handshake(Records, undefined) -> - HsState = #dtls_hs_state{highest_record_seq = 0, - starting_read_seq = 0, - fragments = gb_trees:empty(), - completed = []}, - get_dtls_handshake(Records, HsState); -get_dtls_handshake(Records, HsState0) when is_list(Records) -> - HsState1 = lists:foldr(fun get_dtls_handshake_aux/2, HsState0, Records), - get_dtls_handshake_completed(HsState1); -get_dtls_handshake(Record, HsState0) when is_record(Record, ssl_tls) -> - HsState1 = get_dtls_handshake_aux(Record, HsState0), - get_dtls_handshake_completed(HsState1). +fragment_handshake(Bin, _) when is_binary(Bin)-> + %% This is the change_cipher_spec not a "real handshake" but part of the flight + Bin; +fragment_handshake([MsgType, Len, Seq, _, Len, Bin], Size) -> + Bins = bin_fragments(Bin, Size), + handshake_fragments(MsgType, Seq, Len, Bins, []). +handshake_bin([Type, Length, Data], Seq) -> + handshake_bin(Type, Length, Seq, Data). + %%-------------------------------------------------------------------- --spec dtls_handshake_new_epoch(#dtls_hs_state{}) -> #dtls_hs_state{}. +-spec get_dtls_handshake(dtls_record:dtls_version(), binary(), #protocol_buffers{}) -> + {[{dtls_handshake(), binary()}], #protocol_buffers{}} | {more_data, #protocol_buffers{}}. %% -%% Description: Reset the DTLS decoder state for a new Epoch +%% Description: ... %%-------------------------------------------------------------------- -%% dtls_handshake_new_epoch(<<>>) -> -%% dtls_hs_state_init(); -dtls_handshake_new_epoch(HsState) -> - HsState#dtls_hs_state{highest_record_seq = 0, - starting_read_seq = HsState#dtls_hs_state.current_read_seq, - fragments = gb_trees:empty(), completed = []}. - -%-------------------------------------------------------------------- --spec dtls_handshake_new_flight(integer() | undefined) -> #dtls_hs_state{}. -% -% Description: Init the DTLS decoder state for a new Flight -dtls_handshake_new_flight(ExpectedReadReq) -> - #dtls_hs_state{current_read_seq = ExpectedReadReq, - highest_record_seq = 0, - starting_read_seq = 0, - fragments = gb_trees:empty(), completed = []}. +get_dtls_handshake(Version, Fragment, ProtocolBuffers) -> + handle_fragments(Version, Fragment, ProtocolBuffers, []). %%-------------------------------------------------------------------- %%% Internal functions @@ -170,27 +150,29 @@ handle_client_hello(Version, #client_hello{session_id = SugesstedId, cipher_suites = CipherSuites, compression_methods = Compressions, random = Random, - extensions = #hello_extensions{elliptic_curves = Curves, - signature_algs = ClientHashSigns} = HelloExt}, + extensions = + #hello_extensions{elliptic_curves = Curves, + signature_algs = ClientHashSigns} = HelloExt}, #ssl_options{versions = Versions, signature_algs = SupportedHashSigns} = SslOpts, {Port, Session0, Cache, CacheCb, ConnectionStates0, Cert, _}, Renegotiation) -> case dtls_record:is_acceptable_version(Version, Versions) of true -> + TLSVersion = dtls_v1:corresponding_tls_version(Version), AvailableHashSigns = ssl_handshake:available_signature_algs( - ClientHashSigns, SupportedHashSigns, Cert, - dtls_v1:corresponding_tls_version(Version)), - ECCCurve = ssl_handshake:select_curve(Curves, ssl_handshake:supported_ecc(Version)), + ClientHashSigns, SupportedHashSigns, Cert,TLSVersion), + ECCCurve = ssl_handshake:select_curve(Curves, ssl_handshake:supported_ecc(TLSVersion)), {Type, #session{cipher_suite = CipherSuite} = Session1} = ssl_handshake:select_session(SugesstedId, CipherSuites, AvailableHashSigns, Compressions, - Port, Session0#session{ecc = ECCCurve}, Version, + Port, Session0#session{ecc = ECCCurve}, TLSVersion, SslOpts, Cache, CacheCb, Cert), case CipherSuite of no_suite -> ?ALERT_REC(?FATAL, ?INSUFFICIENT_SECURITY); _ -> {KeyExAlg,_,_,_} = ssl_cipher:suite_definition(CipherSuite), - case ssl_handshake:select_hashsign(ClientHashSigns, Cert, KeyExAlg, SupportedHashSigns, Version) of + case ssl_handshake:select_hashsign(ClientHashSigns, Cert, KeyExAlg, + SupportedHashSigns, TLSVersion) of #alert{} = Alert -> Alert; HashSign -> @@ -228,214 +210,15 @@ handle_server_hello_extensions(Version, SessionId, Random, CipherSuite, {Version, SessionId, ConnectionStates, ProtoExt, Protocol} end. -get_dtls_handshake_completed(HsState = #dtls_hs_state{completed = Completed}) -> - {lists:reverse(Completed), HsState#dtls_hs_state{completed = []}}. - -get_dtls_handshake_aux(#ssl_tls{version = Version, - sequence_number = SeqNo, - fragment = Data}, HsState) -> - get_dtls_handshake_aux(Version, SeqNo, Data, HsState). - -get_dtls_handshake_aux(Version, SeqNo, - <>, - HsState0) -> - case reassemble_dtls_fragment(SeqNo, Type, Length, MessageSeq, - FragmentOffset, FragmentLength, - Body, HsState0) of - {HsState1, HighestSeqNo, MsgBody} -> - HsState2 = dec_dtls_fragment(Version, HighestSeqNo, Type, Length, MessageSeq, MsgBody, HsState1), - HsState3 = process_dtls_fragments(Version, HsState2), - get_dtls_handshake_aux(Version, SeqNo, Rest, HsState3); - - HsState2 -> - HsState3 = process_dtls_fragments(Version, HsState2), - get_dtls_handshake_aux(Version, SeqNo, Rest, HsState3) - end; - -get_dtls_handshake_aux(_Version, _SeqNo, <<>>, HsState) -> - HsState. - -dec_dtls_fragment(Version, SeqNo, Type, Length, MessageSeq, MsgBody, - HsState = #dtls_hs_state{highest_record_seq = HighestSeqNo, completed = Acc}) -> - Raw = <>, - H = decode_handshake(Version, Type, MsgBody), - HsState#dtls_hs_state{completed = [{H,Raw}|Acc], highest_record_seq = erlang:max(HighestSeqNo, SeqNo)}. - -process_dtls_fragments(Version, - HsState0 = #dtls_hs_state{current_read_seq = CurrentReadSeq, - fragments = Fragments0}) -> - case gb_trees:is_empty(Fragments0) of - true -> - HsState0; - _ -> - case gb_trees:smallest(Fragments0) of - {CurrentReadSeq, {SeqNo, Type, Length, CurrentReadSeq, {Length, [{0, Length}], MsgBody}}} -> - HsState1 = dtls_hs_state_process_seq(HsState0), - HsState2 = dec_dtls_fragment(Version, SeqNo, Type, Length, CurrentReadSeq, MsgBody, HsState1), - process_dtls_fragments(Version, HsState2); - _ -> - HsState0 - end - end. - -dtls_hs_state_process_seq(HsState0 = #dtls_hs_state{current_read_seq = CurrentReadSeq, - fragments = Fragments0}) -> - Fragments1 = gb_trees:delete_any(CurrentReadSeq, Fragments0), - HsState0#dtls_hs_state{current_read_seq = CurrentReadSeq + 1, - fragments = Fragments1}. - -dtls_hs_state_add_fragment(MessageSeq, Fragment, HsState0 = #dtls_hs_state{fragments = Fragments0}) -> - Fragments1 = gb_trees:enter(MessageSeq, Fragment, Fragments0), - HsState0#dtls_hs_state{fragments = Fragments1}. - -reassemble_dtls_fragment(SeqNo, Type, Length, MessageSeq, 0, Length, - Body, HsState0 = #dtls_hs_state{current_read_seq = undefined}) - when Type == ?CLIENT_HELLO; - Type == ?SERVER_HELLO; - Type == ?HELLO_VERIFY_REQUEST -> - %% First message, should be client hello - %% return the current message and set the next expected Sequence - %% - %% Note: this could (should?) be restricted further, ClientHello and - %% HelloVerifyRequest have to have message_seq = 0, ServerHello - %% can have a message_seq of 0 or 1 - %% - {HsState0#dtls_hs_state{current_read_seq = MessageSeq + 1}, SeqNo, Body}; - -reassemble_dtls_fragment(_SeqNo, _Type, Length, _MessageSeq, _, Length, - _Body, HsState = #dtls_hs_state{current_read_seq = undefined}) -> - %% not what we expected, drop it - HsState; - -reassemble_dtls_fragment(SeqNo, _Type, Length, MessageSeq, 0, Length, - Body, HsState0 = - #dtls_hs_state{starting_read_seq = StartingReadSeq}) - when MessageSeq < StartingReadSeq -> - %% this has to be the start of a new flight, let it through - %% - %% Note: this could (should?) be restricted further, the first message of a - %% new flight has to have message_seq = 0 - %% - HsState = dtls_hs_state_process_seq(HsState0), - {HsState, SeqNo, Body}; - -reassemble_dtls_fragment(_SeqNo, _Type, Length, MessageSeq, 0, Length, - _Body, HsState = #dtls_hs_state{current_read_seq = CurrentReadSeq}) - when MessageSeq < CurrentReadSeq -> - HsState; - -reassemble_dtls_fragment(SeqNo, _Type, Length, MessageSeq, 0, Length, - Body, HsState0 = #dtls_hs_state{current_read_seq = MessageSeq}) -> - %% Message fully contained and it's the current seq - HsState1 = dtls_hs_state_process_seq(HsState0), - {HsState1, SeqNo, Body}; - -reassemble_dtls_fragment(SeqNo, Type, Length, MessageSeq, 0, Length, - Body, HsState) -> - %% Message fully contained and it's the NOT the current seq -> buffer - Fragment = {SeqNo, Type, Length, MessageSeq, - dtls_fragment_init(Length, 0, Length, Body)}, - dtls_hs_state_add_fragment(MessageSeq, Fragment, HsState); - -reassemble_dtls_fragment(_SeqNo, _Type, Length, MessageSeq, FragmentOffset, FragmentLength, - _Body, - HsState = #dtls_hs_state{current_read_seq = CurrentReadSeq}) - when FragmentOffset + FragmentLength == Length andalso MessageSeq == (CurrentReadSeq - 1) -> - {retransmit, HsState}; - -reassemble_dtls_fragment(_SeqNo, _Type, _Length, MessageSeq, _FragmentOffset, _FragmentLength, - _Body, - HsState = #dtls_hs_state{current_read_seq = CurrentReadSeq}) - when MessageSeq < CurrentReadSeq -> - HsState; - -reassemble_dtls_fragment(SeqNo, Type, Length, MessageSeq, - FragmentOffset, FragmentLength, - Body, - HsState = #dtls_hs_state{fragments = Fragments0}) -> - case gb_trees:lookup(MessageSeq, Fragments0) of - {value, Fragment} -> - dtls_fragment_reassemble(SeqNo, Type, Length, MessageSeq, - FragmentOffset, FragmentLength, - Body, Fragment, HsState); - none -> - dtls_fragment_start(SeqNo, Type, Length, MessageSeq, - FragmentOffset, FragmentLength, - Body, HsState) - end. -dtls_fragment_start(SeqNo, Type, Length, MessageSeq, - FragmentOffset, FragmentLength, - Body, HsState = #dtls_hs_state{fragments = Fragments0}) -> - Fragment = {SeqNo, Type, Length, MessageSeq, - dtls_fragment_init(Length, FragmentOffset, FragmentLength, Body)}, - Fragments1 = gb_trees:insert(MessageSeq, Fragment, Fragments0), - HsState#dtls_hs_state{fragments = Fragments1}. - -dtls_fragment_reassemble(SeqNo, Type, Length, MessageSeq, - FragmentOffset, FragmentLength, - Body, - {LastSeqNo, Type, Length, MessageSeq, FragBuffer0}, - HsState = #dtls_hs_state{fragments = Fragments0}) -> - FragBuffer1 = dtls_fragment_add(FragBuffer0, FragmentOffset, FragmentLength, Body), - Fragment = {erlang:max(SeqNo, LastSeqNo), Type, Length, MessageSeq, FragBuffer1}, - Fragments1 = gb_trees:enter(MessageSeq, Fragment, Fragments0), - HsState#dtls_hs_state{fragments = Fragments1}; - -%% Type, Length or Seq mismatch, drop everything... -%% Note: the RFC is not clear on how to handle this... -dtls_fragment_reassemble(_SeqNo, _Type, _Length, MessageSeq, - _FragmentOffset, _FragmentLength, _Body, _Fragment, - HsState = #dtls_hs_state{fragments = Fragments0}) -> - Fragments1 = gb_trees:delete_any(MessageSeq, Fragments0), - HsState#dtls_hs_state{fragments = Fragments1}. - -dtls_fragment_add({Length, FragmentList0, Bin0}, FragmentOffset, FragmentLength, Body) -> - Bin1 = dtls_fragment_bin_add(FragmentOffset, FragmentLength, Body, Bin0), - FragmentList1 = add_fragment(FragmentList0, {FragmentOffset, FragmentLength}), - {Length, FragmentList1, Bin1}. - -dtls_fragment_init(Length, 0, Length, Body) -> - {Length, [{0, Length}], Body}; -dtls_fragment_init(Length, FragmentOffset, FragmentLength, Body) -> - Bin = dtls_fragment_bin_add(FragmentOffset, FragmentLength, Body, <<0:(Length*8)>>), - {Length, [{FragmentOffset, FragmentOffset + FragmentLength}], Bin}. - -dtls_fragment_bin_add(FragmentOffset, FragmentLength, Add, Buffer) -> - <> = Buffer, - <>. - -merge_fragment_list([], Fragment, Acc) -> - lists:reverse([Fragment|Acc]); - -merge_fragment_list([H = {_, HEnd}|Rest], Frag = {FStart, _}, Acc) - when FStart > HEnd -> - merge_fragment_list(Rest, Frag, [H|Acc]); - -merge_fragment_list(Rest = [{HStart, _HEnd}|_], Frag = {_FStart, FEnd}, Acc) - when FEnd < HStart -> - lists:reverse(Acc) ++ [Frag|Rest]; - -merge_fragment_list([{HStart, HEnd}|Rest], _Frag = {FStart, FEnd}, Acc) - when - FStart =< HEnd orelse FEnd >= HStart -> - Start = erlang:min(HStart, FStart), - End = erlang:max(HEnd, FEnd), - NewFrag = {Start, End}, - merge_fragment_list(Rest, NewFrag, Acc). - -add_fragment(List, {FragmentOffset, FragmentLength}) -> - merge_fragment_list(List, {FragmentOffset, FragmentOffset + FragmentLength}, []). +%%%%%%% Encodeing %%%%%%%%%%%%% enc_handshake(#hello_verify_request{protocol_version = {Major, Minor}, cookie = Cookie}, _Version) -> - CookieLength = byte_size(Cookie), + CookieLength = byte_size(Cookie), {?HELLO_VERIFY_REQUEST, <>}; + Cookie:CookieLength/binary>>}; enc_handshake(#hello_request{}, _Version) -> {?HELLO_REQUEST, <<>>}; @@ -459,38 +242,246 @@ enc_handshake(#client_hello{client_version = {Major, Minor}, ?BYTE(CookieLength), Cookie/binary, ?UINT16(CsLength), BinCipherSuites/binary, ?BYTE(CmLength), BinCompMethods/binary, ExtensionsBin/binary>>}; + +enc_handshake(#server_hello{} = HandshakeMsg, Version) -> + {Type, <>} = + ssl_handshake:encode_handshake(HandshakeMsg, Version), + {DTLSMajor, DTLSMinor} = dtls_v1:corresponding_dtls_version({Major, Minor}), + {Type, <>}; + enc_handshake(HandshakeMsg, Version) -> ssl_handshake:encode_handshake(HandshakeMsg, Version). -decode_handshake(_Version, ?CLIENT_HELLO, < + bin_fragments(Bin, size(Bin), Size, 0, []). + +bin_fragments(Bin, BinSize, FragSize, Offset, Fragments) -> + case (BinSize - Offset - FragSize) > 0 of + true -> + Frag = binary:part(Bin, {Offset, FragSize}), + bin_fragments(Bin, BinSize, FragSize, Offset + FragSize, [{Frag, Offset} | Fragments]); + false -> + Frag = binary:part(Bin, {Offset, BinSize-Offset}), + lists:reverse([{Frag, Offset} | Fragments]) + end. + +handshake_fragments(_, _, _, [], Acc) -> + lists:reverse(Acc); +handshake_fragments(MsgType, Seq, Len, [{Bin, Offset} | Bins], Acc) -> + FragLen = size(Bin), + handshake_fragments(MsgType, Seq, Len, Bins, + [<> | Acc]). + +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) -> + <>. + +%%%%%%% Decodeing %%%%%%%%%%%%% + +handle_fragments(Version, FragmentData, Buffers0, Acc) -> + Fragments = decode_handshake_fragments(FragmentData), + do_handle_fragments(Version, Fragments, Buffers0, Acc). + +do_handle_fragments(_, [], Buffers, Acc) -> + {lists:reverse(Acc), Buffers}; +do_handle_fragments(Version, [Fragment | Fragments], Buffers0, Acc) -> + case reassemble(Version, Fragment, Buffers0) of + {more_data, _} = More when Acc == []-> + More; + {more_data, Buffers} when Fragments == [] -> + {lists:reverse(Acc), Buffers}; + {more_data, Buffers} -> + do_handle_fragments(Version, Fragments, Buffers, Acc); + {HsPacket, Buffers} -> + do_handle_fragments(Version, Fragments, Buffers, [HsPacket | Acc]) + end. + +decode_handshake(Version, <>) -> + decode_handshake(Version, Type, Bin). + +decode_handshake(_, ?HELLO_REQUEST, <<>>) -> + #hello_request{}; +decode_handshake(_Version, ?CLIENT_HELLO, <>) -> - DecodedExtensions = ssl_handshake:decode_hello_extensions(Extensions), - + DecodedExtensions = ssl_handshake:decode_hello_extensions({client, Extensions}), + #client_hello{ client_version = {Major,Minor}, random = Random, - session_id = Session_ID, cookie = Cookie, + session_id = Session_ID, cipher_suites = ssl_handshake:decode_suites('2_bytes', CipherSuites), compression_methods = Comp_methods, extensions = DecodedExtensions - }; + }; + +decode_handshake(_Version, ?HELLO_VERIFY_REQUEST, <>) -> + #hello_verify_request{protocol_version = {Major, Minor}, + cookie = Cookie}; + +decode_handshake(Version, Tag, <>) -> + %% DTLS specifics stripped + decode_tls_thandshake(Version, Tag, Msg). + +decode_tls_thandshake(Version, Tag, Msg) -> + TLSVersion = dtls_v1:corresponding_tls_version(Version), + ssl_handshake:decode_handshake(TLSVersion, Tag, Msg). + +decode_handshake_fragments(<<>>) -> + [<<>>]; +decode_handshake_fragments(<>) -> + [#handshake_fragment{type = Type, + length = Length, + message_seq = MessageSeq, + fragment_offset = FragmentOffset, + fragment_length = FragmentLength, + fragment = Fragment} | decode_handshake_fragments(Rest)]. + +reassemble(Version, #handshake_fragment{message_seq = Seq} = Fragment, + #protocol_buffers{dtls_handshake_next_seq = Seq, + dtls_handshake_next_fragments = Fragments0, + dtls_handshake_later_fragments = LaterFragments0} = + Buffers0)-> + case reassemble_fragments(Fragment, Fragments0) of + {more_data, Fragments} -> + {more_data, Buffers0#protocol_buffers{dtls_handshake_next_fragments = Fragments}}; + {raw, RawHandshake} -> + Handshake = decode_handshake(Version, RawHandshake), + {NextFragments, LaterFragments} = next_fragments(LaterFragments0), + {{Handshake, RawHandshake}, Buffers0#protocol_buffers{dtls_handshake_next_seq = Seq + 1, + dtls_handshake_next_fragments = NextFragments, + dtls_handshake_later_fragments = LaterFragments}} + end; +reassemble(_, #handshake_fragment{message_seq = FragSeq} = Fragment, + #protocol_buffers{dtls_handshake_next_seq = Seq, + dtls_handshake_later_fragments = LaterFragments} = Buffers0) when FragSeq > Seq-> + {more_data, + Buffers0#protocol_buffers{dtls_handshake_later_fragments = [Fragment | LaterFragments]}}; +reassemble(_, _, Buffers) -> + %% Disregard fragments FragSeq < Seq + {more_data, Buffers}. + +reassemble_fragments(Current, Fragments0) -> + [Frag1 | Frags] = lists:keysort(#handshake_fragment.fragment_offset, [Current | Fragments0]), + [Fragment | _] = Fragments = merge_fragment(Frag1, Frags), + case is_complete_handshake(Fragment) of + true -> + {raw, handshake_bin(Fragment)}; + false -> + {more_data, Fragments} + end. -decode_handshake(_Version, ?HELLO_VERIFY_REQUEST, <>) -> +merge_fragment(Frag0, []) -> + [Frag0]; +merge_fragment(Frag0, [Frag1 | Rest]) -> + case merge_fragments(Frag0, Frag1) of + [_|_] = Frags -> + Frags ++ Rest; + Frag -> + merge_fragment(Frag, Rest) + end. - #hello_verify_request{ - protocol_version = {Major,Minor}, - cookie = Cookie}; -decode_handshake(Version, Tag, Msg) -> - ssl_handshake:decode_handshake(Version, Tag, Msg). +is_complete_handshake(#handshake_fragment{length = Length, fragment_length = Length}) -> + true; +is_complete_handshake(_) -> + false. + +next_fragments(LaterFragments) -> + case lists:keysort(#handshake_fragment.message_seq, LaterFragments) of + [] -> + {[], []}; + [#handshake_fragment{message_seq = Seq} | _] = Fragments -> + split_frags(Fragments, Seq, []) + 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) -> -%% <>. +split_frags([#handshake_fragment{message_seq = Seq} = Frag | Rest], Seq, Acc) -> + split_frags(Rest, Seq, [Frag | Acc]); +split_frags(Frags, _, Acc) -> + {lists:reverse(Acc), Frags}. + + +%% Duplicate +merge_fragments(#handshake_fragment{ + fragment_offset = PreviousOffSet, + fragment_length = PreviousLen, + fragment = PreviousData + } = Previous, + #handshake_fragment{ + fragment_offset = PreviousOffSet, + fragment_length = PreviousLen, + fragment = PreviousData}) -> + Previous; + +%% Lager fragment save new data +merge_fragments(#handshake_fragment{ + fragment_offset = PreviousOffSet, + fragment_length = PreviousLen, + fragment = PreviousData + } = Previous, + #handshake_fragment{ + fragment_offset = PreviousOffSet, + fragment_length = CurrentLen, + fragment = CurrentData}) when CurrentLen > PreviousLen -> + NewLength = CurrentLen - PreviousLen, + <<_:PreviousLen/binary, NewData/binary>> = CurrentData, + Previous#handshake_fragment{ + fragment_length = PreviousLen + NewLength, + fragment = <> + }; + +%% Smaller fragment +merge_fragments(#handshake_fragment{ + fragment_offset = PreviousOffSet, + fragment_length = PreviousLen + } = Previous, + #handshake_fragment{ + fragment_offset = PreviousOffSet, + fragment_length = CurrentLen}) when CurrentLen < PreviousLen -> + Previous; +%% Next fragment +merge_fragments(#handshake_fragment{ + fragment_offset = PreviousOffSet, + fragment_length = PreviousLen, + fragment = PreviousData + } = Previous, + #handshake_fragment{ + fragment_offset = CurrentOffSet, + fragment_length = CurrentLen, + fragment = CurrentData}) when PreviousOffSet + PreviousLen == CurrentOffSet-> + Previous#handshake_fragment{ + fragment_length = PreviousLen + CurrentLen, + fragment = <>}; +%% No merge there is a gap +merge_fragments(Previous, Current) -> + [Previous, Current]. + +handshake_bin(#handshake_fragment{ + type = Type, + length = Len, + message_seq = Seq, + fragment_length = Len, + fragment_offset = 0, + fragment = Fragment}) -> + handshake_bin(Type, Len, Seq, Fragment). + +handshake_bin(Type, Length, Seq, FragmentData) -> + <>. -- cgit v1.2.3