// Copyright 2018 The dexon-consensus Authors
// This file is part of the dexon-consensus library.
//
// The dexon-consensus 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 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 library. If not, see
// <http://www.gnu.org/licenses/>.
package test
import (
"encoding/hex"
"errors"
"fmt"
"reflect"
"sort"
"sync"
"github.com/dexon-foundation/dexon-consensus/common"
"github.com/dexon-foundation/dexon-consensus/core/crypto"
"github.com/dexon-foundation/dexon-consensus/core/crypto/ecdsa"
"github.com/dexon-foundation/dexon-consensus/core/types"
typesDKG "github.com/dexon-foundation/dexon-consensus/core/types/dkg"
)
// TODO(mission): add a method to compare config/crs between governance
// instances.
// Governance is an implementation of Goverance for testing purpose.
type Governance struct {
roundShift uint64
configs []*types.Config
nodeSets [][]crypto.PublicKey
roundBeginHeights []uint64
stateModule *State
networkModule *Network
pendingConfigChanges map[uint64]map[StateChangeType]interface{}
prohibitedTypes map[StateChangeType]struct{}
lock sync.RWMutex
}
// NewGovernance constructs a Governance instance.
func NewGovernance(state *State, roundShift uint64) (g *Governance, err error) {
// Setup a State instance.
g = &Governance{
roundShift: roundShift,
pendingConfigChanges: make(map[uint64]map[StateChangeType]interface{}),
stateModule: state,
prohibitedTypes: make(map[StateChangeType]struct{}),
roundBeginHeights: []uint64{0},
}
return
}
// NodeSet implements Governance interface to return current
// notary set.
func (g *Governance) NodeSet(round uint64) []crypto.PublicKey {
if round == 0 || round == 1 {
// Round 0, 1 are genesis round, their configs should be created
// by default.
g.CatchUpWithRound(round)
}
g.lock.RLock()
defer g.lock.RUnlock()
if round >= uint64(len(g.nodeSets)) {
return nil
}
return g.nodeSets[round]
}
// Configuration returns the configuration at a given block height.
func (g *Governance) Configuration(round uint64) *types.Config {
if round == 0 || round == 1 {
// Round 0, 1 are genesis round, their configs should be created
// by default.
g.CatchUpWithRound(round)
}
g.lock.RLock()
defer g.lock.RUnlock()
if round >= uint64(len(g.configs)) {
return nil
}
return g.configs[round]
}
// GetRoundHeight returns the begin height of a round.
func (g *Governance) GetRoundHeight(round uint64) uint64 {
g.lock.RLock()
defer g.lock.RUnlock()
if round >= uint64(len(g.roundBeginHeights)) {
panic(fmt.Errorf("round begin height is not ready: %d %d",
round, len(g.roundBeginHeights)))
}
return g.roundBeginHeights[round]
}
// CRS returns the CRS for a given round.
func (g *Governance) CRS(round uint64) common.Hash {
return g.stateModule.CRS(round)
}
// NotifyRound notifies governace contract to snapshot config, and broadcast
// pending state change requests for next round if any.
func (g *Governance) NotifyRound(round, beginHeight uint64) {
// Snapshot configuration for the shifted round, this behavior is synced with
// full node's implementation.
shiftedRound := round + g.roundShift
g.CatchUpWithRound(shiftedRound)
// Apply change request for next round.
func() {
g.lock.Lock()
defer g.lock.Unlock()
// Check if there is any pending changes for previous rounds.
for r := range g.pendingConfigChanges {
if r < shiftedRound+1 {
panic(fmt.Errorf("pending change no longer applied: %v, now: %v",
r, shiftedRound+1))
}
}
for t, v := range g.pendingConfigChanges[shiftedRound+1] {
if err := g.stateModule.RequestChange(t, v); err != nil {
panic(err)
}
}
delete(g.pendingConfigChanges, shiftedRound+1)
g.broadcastPendingStateChanges()
if round == uint64(len(g.roundBeginHeights)) {
g.roundBeginHeights = append(g.roundBeginHeights, beginHeight)
} else if round < uint64(len(g.roundBeginHeights)) {
if beginHeight != g.roundBeginHeights[round] {
panic(fmt.Errorf("mismatched round begin height: %d %d %d",
round, beginHeight, g.roundBeginHeights[round]))
}
} else {
panic(fmt.Errorf("discontinuous round begin height: %d %d %d",
round, beginHeight, len(g.roundBeginHeights)))
}
}()
}
// ProposeCRS propose a CRS.
func (g *Governance) ProposeCRS(round uint64, signedCRS []byte) {
g.lock.Lock()
defer g.lock.Unlock()
crs := crypto.Keccak256Hash(signedCRS)
if err := g.stateModule.ProposeCRS(round, crs); err != nil {
// CRS can be proposed multiple times, other errors are not
// accepted.
if err != ErrDuplicatedChange {
panic(err)
}
return
}
g.broadcastPendingStateChanges()
}
// AddDKGComplaint add a DKGComplaint.
func (g *Governance) AddDKGComplaint(complaint *typesDKG.Complaint) {
if g.isProhibited(StateAddDKGComplaint) {
return
}
if g.IsDKGFinal(complaint.Round) {
return
}
if err := g.stateModule.RequestChange(
StateAddDKGComplaint, complaint); err != nil {
if err != ErrChangeWontApply {
panic(err)
}
}
g.broadcastPendingStateChanges()
}
// DKGComplaints returns the DKGComplaints of round.
func (g *Governance) DKGComplaints(round uint64) []*typesDKG.Complaint {
return g.stateModule.DKGComplaints(round)
}
// AddDKGMasterPublicKey adds a DKGMasterPublicKey.
func (g *Governance) AddDKGMasterPublicKey(masterPublicKey *typesDKG.MasterPublicKey) {
if g.isProhibited(StateAddDKGMasterPublicKey) {
return
}
if g.IsDKGMPKReady(masterPublicKey.Round) {
return
}
if err := g.stateModule.RequestChange(
StateAddDKGMasterPublicKey, masterPublicKey); err != nil {
if err != ErrChangeWontApply {
panic(err)
}
}
g.broadcastPendingStateChanges()
}
// DKGMasterPublicKeys returns the DKGMasterPublicKeys of round.
func (g *Governance) DKGMasterPublicKeys(
round uint64) []*typesDKG.MasterPublicKey {
return g.stateModule.DKGMasterPublicKeys(round)
}
// AddDKGMPKReady adds a DKG ready message.
func (g *Governance) AddDKGMPKReady(ready *typesDKG.MPKReady) {
if err := g.stateModule.RequestChange(
StateAddDKGMPKReady, ready); err != nil {
if err != ErrChangeWontApply {
panic(err)
}
}
g.broadcastPendingStateChanges()
}
// IsDKGMPKReady checks if DKG is ready.
func (g *Governance) IsDKGMPKReady(round uint64) bool {
if round == 0 || round == 1 {
// Round 0, 1 are genesis round, their configs should be created
// by default.
g.CatchUpWithRound(round)
}
g.lock.RLock()
defer g.lock.RUnlock()
if round >= uint64(len(g.configs)) {
return false
}
return g.stateModule.IsDKGMPKReady(round, int(g.configs[round].DKGSetSize)/3*2)
}
// AddDKGFinalize adds a DKG finalize message.
func (g *Governance) AddDKGFinalize(final *typesDKG.Finalize) {
if g.isProhibited(StateAddDKGFinal) {
return
}
if err := g.stateModule.RequestChange(StateAddDKGFinal, final); err != nil {
if err != ErrChangeWontApply {
panic(err)
}
}
g.broadcastPendingStateChanges()
}
// IsDKGFinal checks if DKG is final.
func (g *Governance) IsDKGFinal(round uint64) bool {
if round == 0 || round == 1 {
// Round 0, 1 are genesis round, their configs should be created
// by default.
g.CatchUpWithRound(round)
}
g.lock.RLock()
defer g.lock.RUnlock()
if round >= uint64(len(g.configs)) {
return false
}
return g.stateModule.IsDKGFinal(round, int(g.configs[round].DKGSetSize)/3*2)
}
// ReportForkVote reports a node for forking votes.
func (g *Governance) ReportForkVote(vote1, vote2 *types.Vote) {
}
// ReportForkBlock reports a node for forking blocks.
func (g *Governance) ReportForkBlock(block1, block2 *types.Block) {
}
// ResetDKG resets latest DKG data and propose new CRS.
func (g *Governance) ResetDKG(newSignedCRS []byte) {
g.lock.Lock()
defer g.lock.Unlock()
crs := crypto.Keccak256Hash(newSignedCRS)
if err := g.stateModule.RequestChange(StateResetDKG, crs); err != nil {
// ResetDKG can be proposed multiple times, other errors are not
// accepted.
if err != ErrDuplicatedChange {
panic(err)
}
return
}
g.broadcastPendingStateChanges()
}
// DKGResetCount returns the reset count for DKG of given round.
func (g *Governance) DKGResetCount(round uint64) uint64 {
return g.stateModule.DKGResetCount(round)
}
//
// Test Utilities
//
type packedStateChanges []byte
// This method broadcasts pending state change requests in the underlying
// State instance, this behavior is to simulate tx-gossiping in full nodes.
func (g *Governance) broadcastPendingStateChanges() {
if g.networkModule == nil {
return
}
packed, err := g.stateModule.PackOwnRequests()
if err != nil {
panic(err)
}
if err := g.networkModule.Broadcast(packedStateChanges(packed)); err != nil {
panic(err)
}
}
// State allows to access embed State instance.
func (g *Governance) State() *State {
return g.stateModule
}
// CatchUpWithRound attempts to perform state snapshot to
// provide configuration/nodeSet for round R.
func (g *Governance) CatchUpWithRound(round uint64) {
if func() bool {
g.lock.RLock()
defer g.lock.RUnlock()
return uint64(len(g.configs)) > round
}() {
return
}
g.lock.Lock()
defer g.lock.Unlock()
for uint64(len(g.configs)) <= round {
config, nodeSet := g.stateModule.Snapshot()
g.configs = append(g.configs, config)
g.nodeSets = append(g.nodeSets, nodeSet)
}
if round >= 1 && len(g.roundBeginHeights) == 1 {
// begin height of round 0 and round 1 should be ready, they won't be
// afected by DKG reset mechanism.
g.roundBeginHeights = append(g.roundBeginHeights,
g.configs[0].RoundLength)
}
}
// Clone a governance instance with replicate internal state.
func (g *Governance) Clone() *Governance {
g.lock.RLock()
defer g.lock.RUnlock()
// Clone state.
copiedState := g.stateModule.Clone()
// Clone configs.
copiedConfigs := []*types.Config{}
for _, c := range g.configs {
copiedConfigs = append(copiedConfigs, c.Clone())
}
// Clone node sets.
copiedPendingChanges := make(map[uint64]map[StateChangeType]interface{})
for round, forRound := range g.pendingConfigChanges {
copiedForRound := make(map[StateChangeType]interface{})
for k, v := range forRound {
copiedForRound[k] = v
}
copiedPendingChanges[round] = copiedForRound
}
// NOTE: here I assume the key is from ecdsa.
copiedNodeSets := [][]crypto.PublicKey{}
for _, nodeSetForRound := range g.nodeSets {
copiedNodeSet := []crypto.PublicKey{}
for _, node := range nodeSetForRound {
pubKey, err := ecdsa.NewPublicKeyFromByteSlice(node.Bytes())
if err != nil {
panic(err)
}
copiedNodeSet = append(copiedNodeSet, pubKey)
}
copiedNodeSets = append(copiedNodeSets, copiedNodeSet)
}
// Clone prohibited flag.
copiedProhibitedTypes := make(map[StateChangeType]struct{})
for t := range g.prohibitedTypes {
copiedProhibitedTypes[t] = struct{}{}
}
// Clone pending changes.
return &Governance{
roundShift: g.roundShift,
configs: copiedConfigs,
stateModule: copiedState,
nodeSets: copiedNodeSets,
pendingConfigChanges: copiedPendingChanges,
prohibitedTypes: copiedProhibitedTypes,
}
}
// Equal checks equality between two Governance instances.
func (g *Governance) Equal(other *Governance, checkState bool) bool {
// Check roundShift.
if g.roundShift != other.roundShift {
return false
}
// Check configs.
if !reflect.DeepEqual(g.configs, other.configs) {
return false
}
// Check node sets.
if len(g.nodeSets) != len(other.nodeSets) {
return false
}
// Check pending changes.
if !reflect.DeepEqual(g.pendingConfigChanges, other.pendingConfigChanges) {
return false
}
// Check prohibited types.
if !reflect.DeepEqual(g.prohibitedTypes, other.prohibitedTypes) {
return false
}
getSortedKeys := func(keys []crypto.PublicKey) (encoded []string) {
for _, key := range keys {
encoded = append(encoded, hex.EncodeToString(key.Bytes()))
}
sort.Strings(encoded)
return
}
for round, nodeSetsForRound := range g.nodeSets {
otherNodeSetsForRound := other.nodeSets[round]
if len(nodeSetsForRound) != len(otherNodeSetsForRound) {
return false
}
if !reflect.DeepEqual(
getSortedKeys(nodeSetsForRound),
getSortedKeys(otherNodeSetsForRound)) {
return false
}
}
// Check state if needed.
//
// While testing, it's expected that two governance instances contain
// different state, only the snapshots (configs and node sets) are
// essentially equal.
if checkState {
return g.stateModule.Equal(other.stateModule) == nil
}
return true
}
// RegisterConfigChange tells this governance instance to request some
// configuration change at some round.
// NOTE: you can't request config change for round 0, 1, they are genesis
// rounds.
// NOTE: this function should be called before running.
func (g *Governance) RegisterConfigChange(
round uint64, t StateChangeType, v interface{}) (err error) {
if t < StateAddCRS || t > StateChangeDKGSetSize {
return fmt.Errorf("state changes to register is not supported: %v", t)
}
if round < 2 {
return errors.New(
"attempt to register state change for genesis rounds")
}
g.lock.Lock()
defer g.lock.Unlock()
if round < uint64(len(g.configs)) {
return errors.New(
"attempt to register state change for prepared rounds")
}
pendingChangesForRound, exists := g.pendingConfigChanges[round]
if !exists {
pendingChangesForRound = make(map[StateChangeType]interface{})
g.pendingConfigChanges[round] = pendingChangesForRound
}
pendingChangesForRound[t] = v
return nil
}
// SwitchToRemoteMode would switch this governance instance to remote mode,
// which means: it will broadcast all changes from its underlying state
// instance.
func (g *Governance) SwitchToRemoteMode(n *Network) {
if g.networkModule != nil {
panic(errors.New("not in local mode before switching"))
}
g.stateModule.SwitchToRemoteMode()
g.networkModule = n
n.addStateModule(g.stateModule)
}
// Prohibit would prohibit DKG related state change requests.
//
// Note this method only prevents local modification, state changes related to
// DKG from others won't be prohibited.
func (g *Governance) Prohibit(t StateChangeType) {
g.lock.Lock()
defer g.lock.Unlock()
switch t {
case StateAddDKGMasterPublicKey, StateAddDKGFinal, StateAddDKGComplaint:
g.prohibitedTypes[t] = struct{}{}
default:
panic(fmt.Errorf("unsupported state change type to prohibit: %s", t))
}
}
// Unprohibit would unprohibit DKG related state change requests.
func (g *Governance) Unprohibit(t StateChangeType) {
g.lock.Lock()
defer g.lock.Unlock()
delete(g.prohibitedTypes, t)
}
// isProhibited checks if a state change request is prohibited or not.
func (g *Governance) isProhibited(t StateChangeType) (prohibited bool) {
g.lock.RLock()
defer g.lock.RUnlock()
_, prohibited = g.prohibitedTypes[t]
return
}
