dbft: specify rejected hashes on CV construction

Ref. nspcc-dev/neo-go#4148.

Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>

Author: AnnaShaleva

CHANGELOG.md

@@ -7,6 +7,7 @@ This document outlines major changes between releases.
 New features:
 
 Behaviour changes:
+ * specify rejected hashes on ChangeView construction (#158)
 
 Improvements:
  * minimum required Go version is 1.25 (#144, #156)

config.go

@@ -58,8 +58,8 @@ type Config[H Hash] struct {
 	GetVerified func() []Transaction[H]
 	// VerifyPreBlock verifies if preBlock is valid.
 	VerifyPreBlock func(b PreBlock[H]) bool
-	// VerifyBlock verifies if block is valid.
-	VerifyBlock func(b Block[H]) bool
+	// VerifyBlock verifies if block is valid and optionally returns the hash of invalid transaction.
+	VerifyBlock func(b Block[H]) (bool, H)
 	// Broadcast should broadcast payload m to the consensus nodes.
 	Broadcast func(m ConsensusPayload[H])
 	// ProcessBlock is called every time new preBlock is accepted.
@@ -86,7 +86,7 @@ type Config[H Hash] struct {
 	// NewPrepareResponse is a constructor for payload.PrepareResponse.
 	NewPrepareResponse func(preparationHash H) PrepareResponse[H]
 	// NewChangeView is a constructor for payload.ChangeView.
-	NewChangeView func(newViewNumber byte, reason ChangeViewReason, timestamp uint64) ChangeView
+	NewChangeView func(newViewNumber byte, reason ChangeViewReason, timestamp uint64, rejectedHash ...H) ChangeView
 	// NewPreCommit is a constructor for payload.PreCommit.
 	NewPreCommit func(data []byte) PreCommit
 	// NewCommit is a constructor for payload.Commit.
@@ -124,7 +124,7 @@ func defaultConfig[H Hash]() *Config[H] {
 		StopTxFlow:         func() {},
 		GetTx:              func(H) Transaction[H] { return nil },
 		GetVerified:        func() []Transaction[H] { return make([]Transaction[H], 0) },
-		VerifyBlock:        func(Block[H]) bool { return true },
+		VerifyBlock:        func(Block[H]) (bool, H) { return true, *new(H) },
 		Broadcast:          func(ConsensusPayload[H]) {},
 		ProcessBlock:       func(Block[H]) error { return nil },
 		GetBlock:           func(H) Block[H] { return nil },
@@ -317,7 +317,7 @@ func WithVerifyPreBlock[H Hash](f func(b PreBlock[H]) bool) func(config *Config[
 }
 
 // WithVerifyBlock sets VerifyBlock.
-func WithVerifyBlock[H Hash](f func(b Block[H]) bool) func(config *Config[H]) {
+func WithVerifyBlock[H Hash](f func(b Block[H]) (bool, H)) func(config *Config[H]) {
 	return func(cfg *Config[H]) {
 		cfg.VerifyBlock = f
 	}
@@ -402,7 +402,7 @@ func WithNewPrepareResponse[H Hash](f func(preparationHash H) PrepareResponse[H]
 }
 
 // WithNewChangeView sets NewChangeView.
-func WithNewChangeView[H Hash](f func(newViewNumber byte, reason ChangeViewReason, ts uint64) ChangeView) func(config *Config[H]) {
+func WithNewChangeView[H Hash](f func(newViewNumber byte, reason ChangeViewReason, ts uint64, rejectedHash ...H) ChangeView) func(config *Config[H]) {
 	return func(cfg *Config[H]) {
 		cfg.NewChangeView = f
 	}

dbft.go

@@ -388,7 +388,10 @@ func (d *DBFT[H]) processMissingTx() {
 // with it, it sends a changeView request and returns false. It's only valid to
 // call it when all transactions for this block are already collected.
 func (d *DBFT[H]) createAndCheckBlock() bool {
-	var blockOK bool
+	var (
+		blockOK  bool
+		invalidH H
+	)
 	if d.isAntiMEVExtensionEnabled() {
 		b := d.CreatePreBlock()
 		blockOK = d.VerifyPreBlock(b)
@@ -397,13 +400,13 @@ func (d *DBFT[H]) createAndCheckBlock() bool {
 		}
 	} else {
 		b := d.CreateBlock()
-		blockOK = d.VerifyBlock(b)
+		blockOK, invalidH = d.VerifyBlock(b)
 		if !blockOK {
 			d.Logger.Warn("proposed block fails verification")
 		}
 	}
 	if !blockOK {
-		d.sendChangeView(CVTxInvalid)
+		d.sendChangeView(CVTxInvalid, invalidH)
 		return false
 	}
 	return true

dbft_test.go

@@ -28,7 +28,7 @@ type testState struct {
 	pool       *testPool
 	preBlocks  []dbft.PreBlock[crypto.Uint256]
 	blocks     []dbft.Block[crypto.Uint256]
-	verify     func(b dbft.Block[crypto.Uint256]) bool
+	verify     func(b dbft.Block[crypto.Uint256]) (bool, crypto.Uint256)
 }
 
 type (
@@ -136,14 +136,14 @@ func TestDBFT_SingleNode(t *testing.T) {
 
 func TestDBFT_OnReceiveRequestSendResponse(t *testing.T) {
 	s := newTestState(2, 7)
-	s.verify = func(b dbft.Block[crypto.Uint256]) bool {
+	s.verify = func(b dbft.Block[crypto.Uint256]) (bool, crypto.Uint256) {
 		for _, tx := range b.Transactions() {
 			if tx.(testTx)%10 == 0 {
-				return false
+				return false, crypto.Uint256{}
 			}
 		}
 
-		return true
+		return true, crypto.Uint256{}
 	}
 
 	t.Run("receive request from primary", func(t *testing.T) {
@@ -551,7 +551,7 @@ func TestDBFT_Invalid(t *testing.T) {
 		require.Error(t, err)
 	})
 
-	opts = append(opts, dbft.WithNewChangeView[crypto.Uint256](func(byte, dbft.ChangeViewReason, uint64) dbft.ChangeView {
+	opts = append(opts, dbft.WithNewChangeView[crypto.Uint256](func(byte, dbft.ChangeViewReason, uint64, ...crypto.Uint256) dbft.ChangeView {
 		return nil
 	}))
 	t.Run("without NewCommit", func(t *testing.T) {
@@ -1165,7 +1165,7 @@ func (s *testState) getOptions() []func(*dbft.Config[crypto.Uint256]) {
 
 	verify := s.verify
 	if verify == nil {
-		verify = func(dbft.Block[crypto.Uint256]) bool { return true }
+		verify = func(dbft.Block[crypto.Uint256]) (bool, crypto.Uint256) { return true, crypto.Uint256{} }
 	}
 
 	opts = append(opts, dbft.WithVerifyBlock(verify))

internal/consensus/constructors.go

@@ -37,7 +37,7 @@ func NewPrepareResponse(preparationHash crypto.Uint256) dbft.PrepareResponse[cry
 }
 
 // NewChangeView returns minimal ChangeView implementation.
-func NewChangeView(newViewNumber byte, _ dbft.ChangeViewReason, ts uint64) dbft.ChangeView {
+func NewChangeView(newViewNumber byte, _ dbft.ChangeViewReason, ts uint64, rejected ...crypto.Uint256) dbft.ChangeView {
 	return &changeView{
 		newViewNumber: newViewNumber,
 		timestamp:     nanoSecToSec(ts),

send.go

@@ -57,16 +57,16 @@ func (d *DBFT[H]) sendPrepareRequest(force bool) {
 	d.checkPrepare()
 }
 
-func (c *Context[H]) makeChangeView(ts uint64, reason ChangeViewReason) ConsensusPayload[H] {
-	cv := c.Config.NewChangeView(c.ViewNumber+1, reason, ts)
+func (c *Context[H]) makeChangeView(ts uint64, reason ChangeViewReason, invalidH ...H) ConsensusPayload[H] {
+	cv := c.Config.NewChangeView(c.ViewNumber+1, reason, ts, invalidH...)
 
 	msg := c.Config.NewConsensusPayload(c, ChangeViewType, cv)
 	c.ChangeViewPayloads[c.MyIndex] = msg
 
 	return msg
 }
 
-func (d *DBFT[H]) sendChangeView(reason ChangeViewReason) {
+func (d *DBFT[H]) sendChangeView(reason ChangeViewReason, invalidH ...H) {
 	if d.Context.WatchOnly() {
 		return
 	}
@@ -97,7 +97,7 @@ func (d *DBFT[H]) sendChangeView(reason ChangeViewReason) {
 		zap.Int("nc", nc),
 		zap.Int("nf", nf))
 
-	msg := d.makeChangeView(uint64(d.Timer.Now().UnixNano()), reason)
+	msg := d.makeChangeView(uint64(d.Timer.Now().UnixNano()), reason, invalidH...)
 	d.StopTxFlow()
 	d.broadcast(msg)
 	d.checkChangeView(newView)