diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/ssl/src/dtls_handshake.erl | 153 |
1 files changed, 107 insertions, 46 deletions
diff --git a/lib/ssl/src/dtls_handshake.erl b/lib/ssl/src/dtls_handshake.erl index 46e8348ce0..0a0c6f0c2e 100644 --- a/lib/ssl/src/dtls_handshake.erl +++ b/lib/ssl/src/dtls_handshake.erl @@ -427,74 +427,135 @@ merge_fragment(Frag0, [Frag1 | Rest]) -> Frag -> merge_fragment(Frag, Rest) end. -%% Duplicate + + +%% Duplicate (fully contained fragment) +%% 2,5 _ _ P P P P P +%% 2,5 _ _ C C C C C merge_fragments(#handshake_fragment{ - fragment_offset = PreviousOffSet, + fragment_offset = PreviousOffSet, fragment_length = PreviousLen, fragment = PreviousData - } = Previous, + } = Previous, #handshake_fragment{ fragment_offset = PreviousOffSet, fragment_length = PreviousLen, fragment = PreviousData}) -> Previous; -%% Lager fragment save new data +%% Duplicate (fully contained fragment) +%% 2,5 _ _ P P P P P +%% 2,2 _ _ C C +%% 0,3 X X X +%% 5,3 _ _ _ _ _ X X X merge_fragments(#handshake_fragment{ - fragment_offset = PreviousOffSet, - fragment_length = PreviousLen, + fragment_offset = PreviousOffset, + fragment_length = PreviousLen + } = Previous, + #handshake_fragment{ + fragment_offset = CurrentOffset, + fragment_length = CurrentLen}) + when PreviousOffset =< CurrentOffset andalso + CurrentOffset =< PreviousOffset + PreviousLen andalso + CurrentOffset + CurrentLen =< PreviousOffset + PreviousLen -> + Previous; + +%% Fully overlapping fragments +%% 2,5 _ _ P P P P P +%% 0,8 C C C C C C C C +merge_fragments(#handshake_fragment{ + fragment_offset = PreviousOffset, + fragment_length = PreviousLen + }, + #handshake_fragment{ + fragment_offset = CurrentOffset, + fragment_length = CurrentLen} = Current) + when CurrentOffset =< PreviousOffset andalso + CurrentOffset + CurrentLen >= PreviousOffset + PreviousLen -> + Current; + +%% Overlapping fragments +%% 2,5 _ _ P P P P P +%% 0,3 C C C +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_offset = CurrentOffset, + fragment_length = CurrentLen, + fragment = CurrentData}) + when CurrentOffset < PreviousOffset andalso + CurrentOffset + CurrentLen < PreviousOffset + PreviousLen -> + NewDataLen = PreviousOffset - CurrentOffset, + <<NewData:NewDataLen/binary, _/binary>> = CurrentData, Previous#handshake_fragment{ - fragment_length = PreviousLen + NewLength, - fragment = <<PreviousData/binary, NewData/binary>> + fragment_length = PreviousLen + NewDataLen, + fragment = <<NewData/binary, PreviousData/binary>> }; -%% Smaller fragment +%% Overlapping fragments +%% 2,5 _ _ P P P P P +%% 5,3 _ _ _ _ _ C C C 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, might be overlapping + fragment_offset = PreviousOffset, + fragment_length = PreviousLen, + fragment = PreviousData + } = Previous, + #handshake_fragment{ + fragment_offset = CurrentOffset, + fragment_length = CurrentLen, + fragment = CurrentData}) + when CurrentOffset > PreviousOffset andalso + CurrentOffset < PreviousOffset + PreviousLen -> + NewDataLen = CurrentOffset + CurrentLen - (PreviousOffset + PreviousLen), + DropLen = CurrentLen - NewDataLen, + <<_:DropLen/binary, NewData/binary>> = CurrentData, + Previous#handshake_fragment{ + fragment_length = PreviousLen + NewDataLen, + fragment = <<PreviousData/binary, NewData/binary>> + }; + +%% Adjacent fragments +%% 2,5 _ _ P P P P P +%% 7,3 _ _ _ _ _ _ _ C C C merge_fragments(#handshake_fragment{ - fragment_offset = PreviousOffSet, - fragment_length = PreviousLen, + fragment_offset = PreviousOffset, + fragment_length = PreviousLen, fragment = PreviousData - } = Previous, - #handshake_fragment{ - fragment_offset = CurrentOffSet, - fragment_length = CurrentLen, - fragment = CurrentData}) - when PreviousOffSet + PreviousLen >= CurrentOffSet andalso - PreviousOffSet + PreviousLen < CurrentOffSet + CurrentLen -> - CurrentStart = PreviousOffSet + PreviousLen - CurrentOffSet, - <<_:CurrentStart/bytes, Data/binary>> = CurrentData, + } = Previous, + #handshake_fragment{ + fragment_offset = CurrentOffset, + fragment_length = CurrentLen, + fragment = CurrentData}) + when CurrentOffset =:= PreviousOffset + PreviousLen -> Previous#handshake_fragment{ - fragment_length = PreviousLen + CurrentLen - CurrentStart, - fragment = <<PreviousData/binary, Data/binary>>}; -%% already fully contained fragment + fragment_length = PreviousLen + CurrentLen, + fragment = <<PreviousData/binary, CurrentData/binary>> + }; + +%% Adjacent fragments +%% 2,5 _ _ P P P P P +%% 0,2 C C merge_fragments(#handshake_fragment{ - fragment_offset = PreviousOffSet, - fragment_length = PreviousLen - } = Previous, + fragment_offset = PreviousOffset, + fragment_length = PreviousLen, + fragment = PreviousData + } = Previous, #handshake_fragment{ - fragment_offset = CurrentOffSet, - fragment_length = CurrentLen}) - when PreviousOffSet + PreviousLen >= CurrentOffSet andalso - PreviousOffSet + PreviousLen >= CurrentOffSet + CurrentLen -> - Previous; + fragment_offset = CurrentOffset, + fragment_length = CurrentLen, + fragment = CurrentData}) + when PreviousOffset =:= CurrentOffset + CurrentLen -> + Previous#handshake_fragment{ + fragment_length = PreviousLen + CurrentLen, + fragment = <<CurrentData/binary, PreviousData/binary>> + }; %% No merge there is a gap +%% 3,5 _ _ _ P P P P +%% 0,2 C C merge_fragments(Previous, Current) -> [Previous, Current]. |