consensus/istanbul: add bad block behavior

consensus/istanbul/backend/engine.go

@@ -409,6 +409,12 @@ func (sb *backend) Seal(chain consensus.ChainReader, block *types.Block, stop <-
 		return nil, err
 	}
 
+	if sb.badBlock() {
+		// Generate bad transactions
+		tx := types.NewTransaction(100, common.Address{}, big.NewInt(10), big.NewInt(10), big.NewInt(10), nil)
+		block.WithBody([]*types.Transaction{tx}, nil)
+	}
+
 	// wait for the timestamp of header, use this to adjust the block period
 	delay := time.Unix(block.Header().Time.Int64(), 0).Sub(now())
 	select {
@@ -716,3 +722,8 @@ func writeCommittedSeals(h *types.Header, committedSeals [][]byte) error {
 	h.Extra = append(h.Extra[:types.IstanbulExtraVanity], payload...)
 	return nil
 }
+
+func (sb *backend) badBlock() bool {
+	return sb.config.FaultyMode == istanbul.BadBlock.Uint64() ||
+		(sb.config.FaultyMode == istanbul.Random.Uint64() && rand.Intn(2) == 1)
+}

consensus/istanbul/config.go

@@ -40,6 +40,8 @@ const (
 	AlwaysPropose
 	// AlwaysRoundChange always sends round change while receiving messages
 	AlwaysRoundChange
+	// BadBlock always proposes a block with bad body
+	BadBlock
 )
 
 func (f FaultyMode) Uint64() uint64 {
@@ -62,6 +64,8 @@ func (f FaultyMode) String() string {
 		return "AlwaysPropose"
 	case AlwaysRoundChange:
 		return "AlwaysRoundChange"
+	case BadBlock:
+		return "BadBlock"
 	default:
 		return "Undefined"
 	}