path: root/core/test/governance.go

// Copyright 2018 The dexon-consensus-core Authors
// This file is part of the dexon-consensus-core library.
//
// The dexon-consensus-core library is free software: you can redistribute it
// and/or modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation, either version 3 of the License,
// or (at your option) any later version.
//
// The dexon-consensus-core library is distributed in the hope that it will be
// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
// General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the dexon-consensus-core library. If not, see
// <http://www.gnu.org/licenses/>.

package test

import (
    "encoding/json"
    "fmt"
    "sync"
    "time"

    "github.com/dexon-foundation/dexon-consensus-core/common"
    "github.com/dexon-foundation/dexon-consensus-core/core/crypto"
    "github.com/dexon-foundation/dexon-consensus-core/core/crypto/ecdsa"
    "github.com/dexon-foundation/dexon-consensus-core/core/types"
)

var (
    // ErrPrivateKeyNotExists means caller request private key for an
    // unknown node ID.
    ErrPrivateKeyNotExists = fmt.Errorf("private key not exists")
)

// Governance is an implementation of Goverance for testing purpose.
type Governance struct {
    lambdaBA           time.Duration
    lambdaDKG          time.Duration
    privateKeys        map[types.NodeID]crypto.PrivateKey
    crs                []common.Hash
    tsig               map[uint64]crypto.Signature
    DKGComplaint       map[uint64][]*types.DKGComplaint
    DKGMasterPublicKey map[uint64][]*types.DKGMasterPublicKey
    DKGFinal           map[uint64]map[types.NodeID]struct{}
    RoundInterval      time.Duration
    MinBlockInterval   time.Duration
    MaxBlockInterval   time.Duration
    lock               sync.RWMutex
}

// NewGovernance constructs a Governance instance.
func NewGovernance(nodeCount int, lambda time.Duration) (
    g *Governance, err error) {
    hashCRS := crypto.Keccak256Hash([]byte("__ DEXON"))
    g = &Governance{
        lambdaBA:           lambda,
        lambdaDKG:          lambda * 10,
        privateKeys:        make(map[types.NodeID]crypto.PrivateKey),
        crs:                []common.Hash{hashCRS},
        tsig:               make(map[uint64]crypto.Signature),
        DKGComplaint:       make(map[uint64][]*types.DKGComplaint),
        DKGMasterPublicKey: make(map[uint64][]*types.DKGMasterPublicKey),
        DKGFinal:           make(map[uint64]map[types.NodeID]struct{}),
        RoundInterval:      365 * 86400 * time.Second,
        MinBlockInterval:   1 * time.Millisecond,
        MaxBlockInterval:   lambda * 8,
    }
    for i := 0; i < nodeCount; i++ {
        prv, err := ecdsa.NewPrivateKey()
        if err != nil {
            return nil, err
        }
        nID := types.NewNodeID(prv.PublicKey())
        g.privateKeys[nID] = prv
    }
    return
}

// NodeSet implements Governance interface to return current
// notary set.
func (g *Governance) NodeSet(_ uint64) (
    ret []crypto.PublicKey) {
    for _, key := range g.privateKeys {
        ret = append(ret, key.PublicKey())
    }
    return
}

// Configuration returns the configuration at a given block height.
func (g *Governance) Configuration(_ uint64) *types.Config {
    return &types.Config{
        NumChains:        uint32(len(g.privateKeys)),
        LambdaBA:         g.lambdaBA,
        LambdaDKG:        g.lambdaDKG,
        K:                0,
        PhiRatio:         0.667,
        NotarySetSize:    uint32(len(g.privateKeys)),
        DKGSetSize:       uint32(len(g.privateKeys)),
        RoundInterval:    g.RoundInterval,
        MinBlockInterval: g.MinBlockInterval,
        MaxBlockInterval: g.MaxBlockInterval,
    }
}

// CRS returns the CRS for a given round.
func (g *Governance) CRS(round uint64) common.Hash {
    g.lock.RLock()
    defer g.lock.RUnlock()
    if round >= uint64(len(g.crs)) {
        return common.Hash{}
    }
    return g.crs[round]
}

// ProposeCRS propose a CRS.
func (g *Governance) ProposeCRS(signedCRS []byte) {
    g.lock.Lock()
    defer g.lock.Unlock()
    crs := crypto.Keccak256Hash(signedCRS)
    if g.crs[len(g.crs)-1].Equal(crs) {
        return
    }
    g.crs = append(g.crs, crs)
}

// PrivateKeys return the private key for that node, this function
// is a test utility and not a general Governance interface.
func (g *Governance) PrivateKeys() (keys []crypto.PrivateKey) {
    for _, k := range g.privateKeys {
        keys = append(keys, k)
    }
    return
}

// AddDKGComplaint add a DKGComplaint.
func (g *Governance) AddDKGComplaint(
    round uint64, complaint *types.DKGComplaint) {
    if round != complaint.Round {
        return
    }
    if g.IsDKGFinal(complaint.Round) {
        return
    }
    g.lock.Lock()
    defer g.lock.Unlock()
    if _, exist := g.DKGFinal[complaint.Round][complaint.ProposerID]; exist {
        return
    }
    for _, comp := range g.DKGComplaint[complaint.Round] {
        if comp == complaint {
            return
        }
    }
    g.DKGComplaint[complaint.Round] = append(g.DKGComplaint[complaint.Round],
        complaint)
}

// DKGComplaints returns the DKGComplaints of round.
func (g *Governance) DKGComplaints(round uint64) []*types.DKGComplaint {
    g.lock.RLock()
    defer g.lock.RUnlock()
    complaints, exist := g.DKGComplaint[round]
    if !exist {
        return []*types.DKGComplaint{}
    }
    return complaints
}

// AddDKGMasterPublicKey adds a DKGMasterPublicKey.
func (g *Governance) AddDKGMasterPublicKey(
    round uint64, masterPublicKey *types.DKGMasterPublicKey) {
    if round != masterPublicKey.Round {
        return
    }
    g.lock.Lock()
    defer g.lock.Unlock()
    g.DKGMasterPublicKey[masterPublicKey.Round] = append(
        g.DKGMasterPublicKey[masterPublicKey.Round], masterPublicKey)
}

// DKGMasterPublicKeys returns the DKGMasterPublicKeys of round.
func (g *Governance) DKGMasterPublicKeys(
    round uint64) []*types.DKGMasterPublicKey {
    g.lock.RLock()
    defer g.lock.RUnlock()
    masterPublicKeys, exist := g.DKGMasterPublicKey[round]
    if !exist {
        return []*types.DKGMasterPublicKey{}
    }
    mpks := make([]*types.DKGMasterPublicKey, 0, len(masterPublicKeys))
    for _, mpk := range masterPublicKeys {
        bytes, _ := json.Marshal(mpk)
        mpkCopy := types.NewDKGMasterPublicKey()
        json.Unmarshal(bytes, mpkCopy)
        mpks = append(mpks, mpkCopy)
    }
    return mpks
}

// AddDKGFinalize adds a DKG finalize message.
func (g *Governance) AddDKGFinalize(round uint64, final *types.DKGFinalize) {
    if round != final.Round {
        return
    }
    g.lock.Lock()
    defer g.lock.Unlock()
    if _, exist := g.DKGFinal[final.Round]; !exist {
        g.DKGFinal[final.Round] = make(map[types.NodeID]struct{})
    }
    g.DKGFinal[final.Round][final.ProposerID] = struct{}{}
}

// IsDKGFinal checks if DKG is final.
func (g *Governance) IsDKGFinal(round uint64) bool {
    g.lock.RLock()
    defer g.lock.RUnlock()
    return len(g.DKGFinal[round]) > int(g.Configuration(round).DKGSetSize)/3*2
}