package consensus import ( "bytes" "fmt" "strings" "sync" "github.com/tendermint/tendermint/account" "github.com/tendermint/tendermint/binary" . "github.com/tendermint/tendermint/common" sm "github.com/tendermint/tendermint/state" "github.com/tendermint/tendermint/types" ) // VoteSet helps collect signatures from validators at each height+round // for a predefined vote type. // Note that there three kinds of votes: prevotes, precommits, and commits. // A commit of prior rounds can be added added in lieu of votes/precommits. // NOTE: Assumes that the sum total of voting power does not exceed MaxUInt64. type VoteSet struct { height uint round uint type_ byte mtx sync.Mutex valSet *sm.ValidatorSet votes []*types.Vote // validator index -> vote votesBitArray BitArray // validator index -> has vote? votesByBlock map[string]uint64 // string(blockHash)+string(blockParts) -> vote sum. totalVotes uint64 maj23Hash []byte maj23Parts types.PartSetHeader maj23Exists bool } // Constructs a new VoteSet struct used to accumulate votes for each round. func NewVoteSet(height uint, round uint, type_ byte, valSet *sm.ValidatorSet) *VoteSet { if height == 0 { panic("Cannot make VoteSet for height == 0, doesn't make sense.") } if type_ == types.VoteTypeCommit && round != 0 { panic("Expected round 0 for commit vote set") } return &VoteSet{ height: height, round: round, type_: type_, valSet: valSet, votes: make([]*types.Vote, valSet.Size()), votesBitArray: NewBitArray(valSet.Size()), votesByBlock: make(map[string]uint64), totalVotes: 0, } } func (voteSet *VoteSet) Height() uint { if voteSet == nil { return 0 } else { return voteSet.height } } func (voteSet *VoteSet) Size() uint { if voteSet == nil { return 0 } else { return voteSet.valSet.Size() } } // True if added, false if not. // Returns ErrVote[UnexpectedStep|InvalidAccount|InvalidSignature|InvalidBlockHash|ConflictingSignature] // NOTE: vote should not be mutated after adding. func (voteSet *VoteSet) Add(address []byte, vote *types.Vote) (bool, uint, error) { voteSet.mtx.Lock() defer voteSet.mtx.Unlock() // Make sure the step matches. (or that vote is commit && round < voteSet.round) if vote.Height != voteSet.height || (vote.Type != types.VoteTypeCommit && vote.Round != voteSet.round) || (vote.Type != types.VoteTypeCommit && vote.Type != voteSet.type_) || (vote.Type == types.VoteTypeCommit && voteSet.type_ != types.VoteTypeCommit && vote.Round >= voteSet.round) { return false, 0, types.ErrVoteUnexpectedStep } // Ensure that signer is a validator. valIndex, val := voteSet.valSet.GetByAddress(address) if val == nil { return false, 0, types.ErrVoteInvalidAccount } // Check signature. if !val.PubKey.VerifyBytes(account.SignBytes(vote), vote.Signature) { // Bad signature. return false, 0, types.ErrVoteInvalidSignature } return voteSet.addVote(valIndex, vote) } func (voteSet *VoteSet) addVote(valIndex uint, vote *types.Vote) (bool, uint, error) { // If vote already exists, return false. if existingVote := voteSet.votes[valIndex]; existingVote != nil { if bytes.Equal(existingVote.BlockHash, vote.BlockHash) { return false, 0, nil } else { return false, 0, &types.ErrVoteConflictingSignature{ VoteA: existingVote, VoteB: vote, } } } // Add vote. _, val := voteSet.valSet.GetByIndex(valIndex) if val == nil { panic(fmt.Sprintf("Missing validator for index %v", valIndex)) } voteSet.votes[valIndex] = vote voteSet.votesBitArray.SetIndex(valIndex, true) blockKey := string(vote.BlockHash) + string(binary.BinaryBytes(vote.BlockParts)) totalBlockHashVotes := voteSet.votesByBlock[blockKey] + val.VotingPower voteSet.votesByBlock[blockKey] = totalBlockHashVotes voteSet.totalVotes += val.VotingPower // If we just nudged it up to two thirds majority, add it. if totalBlockHashVotes > voteSet.valSet.TotalVotingPower()*2/3 && (totalBlockHashVotes-val.VotingPower) <= voteSet.valSet.TotalVotingPower()*2/3 { voteSet.maj23Hash = vote.BlockHash voteSet.maj23Parts = vote.BlockParts voteSet.maj23Exists = true } return true, valIndex, nil } // Assumes that commits VoteSet is valid. func (voteSet *VoteSet) AddFromCommits(commits *VoteSet) { for valIndex, commit := range commits.votes { if commit == nil { continue } if commit.Round < voteSet.round { voteSet.addVote(uint(valIndex), commit) } } } func (voteSet *VoteSet) BitArray() BitArray { if voteSet == nil { return BitArray{} } voteSet.mtx.Lock() defer voteSet.mtx.Unlock() return voteSet.votesBitArray.Copy() } func (voteSet *VoteSet) GetByIndex(valIndex uint) *types.Vote { voteSet.mtx.Lock() defer voteSet.mtx.Unlock() return voteSet.votes[valIndex] } func (voteSet *VoteSet) GetByAddress(address []byte) *types.Vote { voteSet.mtx.Lock() defer voteSet.mtx.Unlock() valIndex, val := voteSet.valSet.GetByAddress(address) if val == nil { panic("GetByAddress(address) returned nil") } return voteSet.votes[valIndex] } func (voteSet *VoteSet) HasTwoThirdsMajority() bool { if voteSet == nil { return false } voteSet.mtx.Lock() defer voteSet.mtx.Unlock() return voteSet.maj23Exists } // Returns either a blockhash (or nil) that received +2/3 majority. // If there exists no such majority, returns (nil, false). func (voteSet *VoteSet) TwoThirdsMajority() (hash []byte, parts types.PartSetHeader, ok bool) { voteSet.mtx.Lock() defer voteSet.mtx.Unlock() if voteSet.maj23Exists { return voteSet.maj23Hash, voteSet.maj23Parts, true } else { return nil, types.PartSetHeader{}, false } } func (voteSet *VoteSet) MakePOL() *POL { if voteSet.type_ != types.VoteTypePrevote { panic("Cannot MakePOL() unless VoteSet.Type is types.VoteTypePrevote") } voteSet.mtx.Lock() defer voteSet.mtx.Unlock() if !voteSet.maj23Exists { return nil } pol := &POL{ Height: voteSet.height, Round: voteSet.round, BlockHash: voteSet.maj23Hash, BlockParts: voteSet.maj23Parts, Votes: make([]POLVoteSignature, voteSet.valSet.Size()), } for valIndex, vote := range voteSet.votes { if vote == nil { continue } if !bytes.Equal(vote.BlockHash, voteSet.maj23Hash) { continue } if !vote.BlockParts.Equals(voteSet.maj23Parts) { continue } pol.Votes[valIndex] = POLVoteSignature{ Round: vote.Round, Signature: vote.Signature, } } return pol } func (voteSet *VoteSet) MakeValidation() *types.Validation { if voteSet.type_ != types.VoteTypeCommit { panic("Cannot MakeValidation() unless VoteSet.Type is types.VoteTypeCommit") } voteSet.mtx.Lock() defer voteSet.mtx.Unlock() if len(voteSet.maj23Hash) == 0 { panic("Cannot MakeValidation() unless a blockhash has +2/3") } commits := make([]types.Commit, voteSet.valSet.Size()) voteSet.valSet.Iterate(func(valIndex uint, val *sm.Validator) bool { vote := voteSet.votes[valIndex] if vote == nil { return false } if !bytes.Equal(vote.BlockHash, voteSet.maj23Hash) { return false } if !vote.BlockParts.Equals(voteSet.maj23Parts) { return false } commits[valIndex] = types.Commit{val.Address, vote.Round, vote.Signature} return false }) return &types.Validation{ Commits: commits, } } func (voteSet *VoteSet) String() string { return voteSet.StringIndented("") } func (voteSet *VoteSet) StringIndented(indent string) string { voteStrings := make([]string, len(voteSet.votes)) for i, vote := range voteSet.votes { if vote == nil { voteStrings[i] = "nil-Vote" } else { voteStrings[i] = vote.String() } } return fmt.Sprintf(`VoteSet{ %s H:%v R:%v T:%v %s %v %s %v %s}`, indent, voteSet.height, voteSet.round, voteSet.type_, indent, strings.Join(voteStrings, "\n"+indent+" "), indent, voteSet.votesBitArray, indent) } func (voteSet *VoteSet) StringShort() string { if voteSet == nil { return "nil-VoteSet" } voteSet.mtx.Lock() defer voteSet.mtx.Unlock() return fmt.Sprintf(`VoteSet{H:%v R:%v T:%v %v}`, voteSet.height, voteSet.round, voteSet.type_, voteSet.votesBitArray) }