// 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 core
import (
"fmt"
"log"
"sync"
"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/types"
)
// Errors for configuration chain..
var (
ErrDKGNotRegistered = fmt.Errorf(
"not yet registered in DKG protocol")
ErrDKGNotReady = fmt.Errorf(
"DKG is not ready")
)
type configurationChain struct {
ID types.NodeID
recv dkgReceiver
gov Governance
dkg *dkgProtocol
dkgLock sync.RWMutex
dkgSigner map[uint64]*dkgShareSecret
gpk map[uint64]*dkgGroupPublicKey
dkgResult sync.RWMutex
tsig *tsigProtocol
tsigReady *sync.Cond
// TODO(jimmy-dexon): add timeout to pending psig.
pendingPsig []*types.DKGPartialSignature
prevHash common.Hash
}
func newConfigurationChain(
ID types.NodeID,
recv dkgReceiver,
gov Governance) *configurationChain {
return &configurationChain{
ID: ID,
recv: recv,
gov: gov,
dkgSigner: make(map[uint64]*dkgShareSecret),
gpk: make(map[uint64]*dkgGroupPublicKey),
tsigReady: sync.NewCond(&sync.Mutex{}),
}
}
func (cc *configurationChain) registerDKG(round uint64, threshold int) {
cc.dkg = newDKGProtocol(
cc.ID,
cc.recv,
round,
threshold)
}
func (cc *configurationChain) runDKG(round uint64) error {
cc.dkgLock.Lock()
defer cc.dkgLock.Unlock()
if cc.dkg == nil || cc.dkg.round != round {
return ErrDKGNotRegistered
}
if func() bool {
cc.dkgResult.RLock()
defer cc.dkgResult.RUnlock()
_, exist := cc.gpk[round]
return exist
}() {
return nil
}
ticker := newTicker(cc.gov, TickerDKG)
cc.dkgLock.Unlock()
<-ticker.Tick()
cc.dkgLock.Lock()
// Phase 2(T = 0): Exchange DKG secret key share.
cc.dkg.processMasterPublicKeys(cc.gov.DKGMasterPublicKeys(round))
// Phase 3(T = 0~λ): Propose complaint.
// Propose complaint is done in `processMasterPublicKeys`.
cc.dkgLock.Unlock()
<-ticker.Tick()
cc.dkgLock.Lock()
// Phase 4(T = λ): Propose nack complaints.
cc.dkg.proposeNackComplaints()
cc.dkgLock.Unlock()
<-ticker.Tick()
cc.dkgLock.Lock()
// Phase 5(T = 2λ): Propose Anti nack complaint.
cc.dkg.processNackComplaints(cc.gov.DKGComplaints(round))
cc.dkgLock.Unlock()
<-ticker.Tick()
cc.dkgLock.Lock()
// Phase 6(T = 3λ): Rebroadcast anti nack complaint.
// Rebroadcast is done in `processPrivateShare`.
cc.dkgLock.Unlock()
<-ticker.Tick()
cc.dkgLock.Lock()
// Phase 7(T = 4λ): Enforce complaints and nack complaints.
cc.dkg.enforceNackComplaints(cc.gov.DKGComplaints(round))
// Enforce complaint is done in `processPrivateShare`.
// Phase 8(T = 5λ): DKG is ready.
cc.dkgLock.Unlock()
<-ticker.Tick()
cc.dkgLock.Lock()
gpk, err := newDKGGroupPublicKey(round,
cc.gov.DKGMasterPublicKeys(round),
cc.gov.DKGComplaints(round),
cc.dkg.threshold)
if err != nil {
return err
}
signer, err := cc.dkg.recoverShareSecret(gpk.qualifyIDs)
if err != nil {
return err
}
qualifies := ""
for _, nID := range gpk.qualifyNodeIDs {
qualifies += fmt.Sprintf("%s ", nID.String()[:6])
}
log.Printf("[%s] Qualify Nodes(%d): %s\n",
cc.ID, len(gpk.qualifyIDs), qualifies)
cc.dkgResult.Lock()
defer cc.dkgResult.Unlock()
cc.dkgSigner[round] = signer
cc.gpk[round] = gpk
return nil
}
func (cc *configurationChain) preparePartialSignature(
round uint64, hash common.Hash) (*types.DKGPartialSignature, error) {
signer, exist := func() (*dkgShareSecret, bool) {
cc.dkgResult.RLock()
defer cc.dkgResult.RUnlock()
signer, exist := cc.dkgSigner[round]
return signer, exist
}()
if !exist {
return nil, ErrDKGNotReady
}
return &types.DKGPartialSignature{
ProposerID: cc.ID,
Round: round,
PartialSignature: signer.sign(hash),
}, nil
}
func (cc *configurationChain) runBlockTSig(
round uint64, hash common.Hash) (crypto.Signature, error) {
gpk, exist := func() (*dkgGroupPublicKey, bool) {
cc.dkgResult.RLock()
defer cc.dkgResult.RUnlock()
gpk, exist := cc.gpk[round]
return gpk, exist
}()
if !exist {
return crypto.Signature{}, ErrDKGNotReady
}
cc.tsigReady.L.Lock()
defer cc.tsigReady.L.Unlock()
cc.tsig = newTSigProtocol(gpk, hash, types.TSigConfigurationBlock)
pendingPsig := cc.pendingPsig
cc.pendingPsig = []*types.DKGPartialSignature{}
go func() {
for _, psig := range pendingPsig {
if err := cc.processPartialSignature(psig); err != nil {
log.Printf("[%s] %s", cc.ID, err)
}
}
}()
var signature crypto.Signature
var err error
for func() bool {
signature, err = cc.tsig.signature()
return err == ErrNotEnoughtPartialSignatures
}() {
cc.tsigReady.Wait()
}
cc.tsig = nil
if err != nil {
return crypto.Signature{}, err
}
log.Printf("[%s] TSIG: %s\n", cc.ID, signature)
return signature, nil
}
func (cc *configurationChain) processPrivateShare(
prvShare *types.DKGPrivateShare) error {
cc.dkgLock.Lock()
defer cc.dkgLock.Unlock()
if cc.dkg == nil {
return nil
}
return cc.dkg.processPrivateShare(prvShare)
}
func (cc *configurationChain) processPartialSignature(
psig *types.DKGPartialSignature) error {
cc.tsigReady.L.Lock()
defer cc.tsigReady.L.Unlock()
if cc.tsig == nil {
ok, err := verifyDKGPartialSignatureSignature(psig)
if err != nil {
return err
}
if !ok {
return ErrIncorrectPartialSignatureSignature
}
cc.pendingPsig = append(cc.pendingPsig, psig)
return nil
}
if err := cc.tsig.processPartialSignature(psig); err != nil {
return err
}
cc.tsigReady.Broadcast()
return nil
}
