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Refactor things to have a common decision function we can call for TE…
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…RM too
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@Vagabond
Vagabond committed Sep 4, 2018
1 parent 11e7051 commit cf0cf02
Showing 1 changed file with 52 additions and 70 deletions.
122 changes: 52 additions & 70 deletions src/hbbft_bba.erl
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Original file line number Diff line number Diff line change
Expand Up @@ -11,10 +11,10 @@
output :: undefined | 0 | 1,
f :: non_neg_integer(),
n :: pos_integer(),
%% XXX I think some of these witnesses can hold more values...
bval_witness = maps:new() :: #{non_neg_integer() => 0 | 1 | 2 | 3},
aux_witness = maps:new() :: #{non_neg_integer() => 0 | 1 | 2 | 3},
conf_witness = maps:new() :: #{non_neg_integer() => 0 | 1},
%% XXX some of these also have the {val, _} keys...
bval_witness = maps:new() :: #{non_neg_integer() => 0 | 1 | 2 | 3, {val, 0 | 1 | both} => non_neg_integer()},
aux_witness = maps:new() :: #{non_neg_integer() => 0 | 1 | 2 | 3, {val, 0 | 1 | both} => non_neg_integer()},
conf_witness = maps:new() :: #{non_neg_integer() => 0 | 1 | 2 | 3},
terminate_witness = maps:new() :: #{non_neg_integer() => 0 | 1},
aux_sent = false :: boolean(),
conf_sent = false :: boolean(),
Expand Down Expand Up @@ -117,7 +117,7 @@ handle_msg(Data = #bba_data{round=R, coin=Coin}, J, {{coin, R}, CMsg}) when Coin
{_NewCoin, {result, Result}} ->
%% ok, we've obtained the common coin
Flip = Result rem 2,
check_coin_flip(Data, Flip);
check_coin_flip({Data, []}, Flip);
{NewCoin, ok} ->
{Data#bba_data{coin=NewCoin}, ok}
end;
Expand All @@ -133,16 +133,16 @@ handle_msg(Data, J, {term, B}) when B == 0; B == 1 ->
Count when Count >= Data#bba_data.f + 1 ->
{NewData#bba_data{state=done}, {result_and_send, B, {send, [{multicast, {term, B}}]}}};
_ ->
%% TODO we need to check bval/aux/conf message thresholds in light of the new TERM message
{NewData, ok}
%% we need to check bval/aux/conf message thresholds in light of the new TERM message
decide(NewData, [])
end;
handle_msg(Data, _J, _Msg) ->
{Data, ok}.

%% – upon receiving BVALr (b) messages from f + 1 nodes, if
%% BVALr (b) has not been sent, multicast BVALr (b)
-spec bval(bba_data(), non_neg_integer(), 0 | 1) -> {bba_data(), {send, [hbbft_utils:multicast(aux_msg() | coin_msg())]}}.
bval(Data=#bba_data{n=N, f=F}, Id, V) ->
bval(Data=#bba_data{f=F}, Id, V) ->
%% add to witnesses
Witness = add_witness(Id, V, Data#bba_data.bval_witness, true),
WitnessCount = maps:get({val, V}, Witness, 0),
Expand Down Expand Up @@ -172,75 +172,22 @@ bval(Data=#bba_data{n=N, f=F}, Id, V) ->
false ->
{NewData2, ToSend}
end,

%% check if we have n-f aux messages
case threshold(N, F, NewData3, aux) of
true ->
case schedule(NewData3#bba_data.round) of
coin ->
%% check if we have n-f conf messages
case threshold(N, F, NewData3, conf) andalso not NewData3#bba_data.coin_sent of
true ->
%% instantiate the common coin
%% TODO need more entropy for the SID
%% We have enough AUX and CONF messages to reveal our share of the coin
{CoinData, {send, CoinSend}} = hbbft_cc:get_coin(maybe_init_coin(NewData3)),
{NewData3#bba_data{coin=CoinData, coin_sent=true}, {send, ToSend2 ++ hbbft_utils:wrap({coin, Data#bba_data.round}, CoinSend)}};
_ ->
{NewData3, {send, ToSend2}}
end;
FixedValue ->
check_coin_flip(NewData3, FixedValue)
end;
false ->
{NewData3, {send, ToSend2}}
end;
decide(NewData3, ToSend2);
false ->
{NewData, {send, ToSend}}
end.

-spec aux(bba_data(), non_neg_integer(), 0 | 1) -> {bba_data(), ok | {send, [hbbft_utils:multicast(conf_msg())]}}.
aux(Data = #bba_data{n=N, f=F}, Id, V) ->
aux(Data, Id, V) ->
Witness = add_witness(Id, V, Data#bba_data.aux_witness, true),
NewData = Data#bba_data{aux_witness = Witness},
case threshold(N, F, NewData, aux) of
true->
case schedule(NewData#bba_data.round) of
coin ->
%% only send conf after n-f aux messages
case NewData#bba_data.conf_sent of
false ->
{NewData#bba_data{conf_sent=true}, {send, [{multicast, {conf, NewData#bba_data.round, NewData#bba_data.bin_values}}]}};
true ->
%% conf was already sent
{NewData, ok}
end;
FixedValue ->
check_coin_flip(NewData, FixedValue)
end;
_ ->
{NewData, ok}
end.
decide(NewData, []).

-spec conf(bba_data(), non_neg_integer(), 0 | 1) -> {bba_data(), ok | {send, [hbbft_utils:multicast(coin_msg())]}}.
conf(Data = #bba_data{n=N, f=F}, Id, V) ->
conf(Data, Id, V) ->
Witness = maps:put(Id, V, Data#bba_data.conf_witness),
NewData = Data#bba_data{conf_witness = Witness},
case threshold(N, F, NewData, aux) of
true->
case threshold(N, F, NewData, conf) andalso not NewData#bba_data.coin_sent of
true ->
%% instantiate the common coin
%% TODO need more entropy for the SID
%% We have enough AUX and CONF messages to reveal our share of the coin
{CoinData, {send, ToSend}} = hbbft_cc:get_coin(maybe_init_coin(NewData)),
{NewData#bba_data{coin=CoinData, coin_sent=true}, {send, hbbft_utils:wrap({coin, NewData#bba_data.round}, ToSend)}};
_ ->
{NewData, ok}
end;
_ ->
{NewData, ok}
end.
decide(NewData, []).

-spec serialize(bba_data()) -> bba_serialized_data().
serialize(#bba_data{state=State,
Expand Down Expand Up @@ -314,6 +261,39 @@ deserialize(#bba_serialized_data{state=State,

%% helper functions


decide(Data=#bba_data{n=N, f=F}, ToSend0) ->
%% check if we have n-f aux messages
case threshold(N, F, Data, aux) of
true ->
case schedule(Data#bba_data.round) of
coin ->
%% only send conf after n-f aux messages
{NewData, ToSend} = case Data#bba_data.conf_sent of
false ->
{Data#bba_data{conf_sent=true}, ToSend0 ++ [{multicast, {conf, Data#bba_data.round, Data#bba_data.bin_values}}]};
true ->
%% conf was already sent
{Data, ToSend0}
end,
%% check if we have n-f conf messages
case threshold(N, F, NewData, conf) andalso not NewData#bba_data.coin_sent of
true ->
%% instantiate the common coin
%% TODO need more entropy for the SID
%% We have enough AUX and CONF messages to reveal our share of the coin
{CoinData, {send, CoinSend}} = hbbft_cc:get_coin(maybe_init_coin(NewData)),
{NewData#bba_data{coin=CoinData, coin_sent=true}, {send, ToSend ++ hbbft_utils:wrap({coin, NewData#bba_data.round}, CoinSend)}};
_ ->
{NewData, {send, ToSend}}
end;
FixedValue ->
check_coin_flip({Data, ToSend0}, FixedValue)
end;
false ->
{Data, {send, ToSend0}}
end.

-spec threshold(pos_integer(), non_neg_integer(), bba_data(), aux | conf) -> boolean().
threshold(N, F, Data, Msg) ->
case Msg of
Expand Down Expand Up @@ -447,7 +427,7 @@ schedule(N) ->
2 -> coin
end.

check_coin_flip(Data, Flip) ->
check_coin_flip({Data, ToSend}, Flip) ->
case count(Data#bba_data.bin_values) == 1 of
true ->
%% if vals = {b}, then
Expand All @@ -463,15 +443,17 @@ check_coin_flip(Data, Flip) ->
true ->
%% we are done
NewData = Data#bba_data{state=done},
{NewData, {result_and_send, B, {send, [{multicast, {term, B}}]}} };
{NewData, {result_and_send, B, {send, ToSend ++ [{multicast, {term, B}}]}} };
false ->
%% increment round and continue
NewData = init(Data#bba_data.secret_key, Data#bba_data.n, Data#bba_data.f),
input(NewData#bba_data{round=Data#bba_data.round + 1, output=Output, terminate_witness=Data#bba_data.terminate_witness}, B)
{NewData2, {send, NewToSend}} = input(NewData#bba_data{round=Data#bba_data.round + 1, output=Output, terminate_witness=Data#bba_data.terminate_witness}, B),
{NewData2, {send, ToSend ++ NewToSend}}
end;
false ->
%% else estr+1 := s%2
B = Flip,
NewData = init(Data#bba_data.secret_key, Data#bba_data.n, Data#bba_data.f),
input(NewData#bba_data{round=Data#bba_data.round + 1, terminate_witness=Data#bba_data.terminate_witness}, B)
{NewData2, {send, NewToSend}} = input(NewData#bba_data{round=Data#bba_data.round + 1, terminate_witness=Data#bba_data.terminate_witness}, B),
{NewData2, {send, ToSend ++ NewToSend}}
end.

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