consensus: fix slash bug when validator set changing (bnb-chain#1162)

brilliant-lx · Mar 1, 2023 · 2a76eb4 · 2a76eb4
1 parent d065c48
commit 2a76eb4
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Showing 2 changed files with 44 additions and 7 deletions.
diff --git a/consensus/parlia/parlia.go b/consensus/parlia/parlia.go
@@ -1298,7 +1298,7 @@ func encodeSigHeader(w io.Writer, header *types.Header, chainId *big.Int) {
 	}
 }
 
-func backOffTime(snap *Snapshot, val common.Address) uint64 {
+func (p *Parlia) backOffTime(snap *Snapshot, header *types.Header, val common.Address) uint64 {
 	if snap.inturn(val) {
 		return 0
 	} else {
@@ -1311,13 +1311,50 @@ func backOffTime(snap *Snapshot, val common.Address) uint64 {
 		r := rand.New(s)
 		n := len(snap.Validators)
 		backOffSteps := make([]uint64, 0, n)
-		for idx := uint64(0); idx < uint64(n); idx++ {
-			backOffSteps = append(backOffSteps, idx)
+
+		if !p.chainConfig.IsBohr(header.Number) {
+			for i := uint64(0); i < uint64(n); i++ {
+				backOffSteps = append(backOffSteps, i)
+			}
+			r.Shuffle(n, func(i, j int) {
+				backOffSteps[i], backOffSteps[j] = backOffSteps[j], backOffSteps[i]
+			})
+			delay := initialBackOffTime + backOffSteps[idx]*wiggleTime
+			return delay
+		}
+
+		// Exclude the recently signed validators first, and then compute the backOffTime.
+		recentVals := make(map[common.Address]bool, len(snap.Recents))
+		//for seen, recent := range snap.Recents {
+		for _, recent := range snap.Recents {
+			if val == recent {
+				// The backOffTime does not matter when a validator has signed recently.
+				return 0
+			}
+			recentVals[recent] = true
 		}
-		r.Shuffle(n, func(i, j int) {
+
+		backOffIndex := idx
+		validators := snap.validators()
+		for i := 0; i < n; i++ {
+			if isRecent, ok := recentVals[validators[i]]; ok && isRecent {
+				if i < idx {
+					backOffIndex--
+				}
+				continue
+			}
+			backOffSteps = append(backOffSteps, uint64(len(backOffSteps)))
+		}
+		r.Shuffle(len(backOffSteps), func(i, j int) {
 			backOffSteps[i], backOffSteps[j] = backOffSteps[j], backOffSteps[i]
 		})
-		delay := initialBackOffTime + backOffSteps[idx]*wiggleTime
+		delay := initialBackOffTime + backOffSteps[backOffIndex]*wiggleTime
+
+		// If the in turn validator has recently signed, no initial delay.
+		inTurnVal := validators[(snap.Number+1)%uint64(len(validators))]
+		if isRecent, ok := recentVals[inTurnVal]; ok && isRecent {
+			delay -= initialBackOffTime
+		}
 		return delay
 	}
 }

diff --git a/consensus/parlia/ramanujanfork.go b/consensus/parlia/ramanujanfork.go
@@ -29,14 +29,14 @@ func (p *Parlia) delayForRamanujanFork(snap *Snapshot, header *types.Header) tim
 func (p *Parlia) blockTimeForRamanujanFork(snap *Snapshot, header, parent *types.Header) uint64 {
 	blockTime := parent.Time + p.config.Period
 	if p.chainConfig.IsRamanujan(header.Number) {
-		blockTime = blockTime + backOffTime(snap, p.val)
+		blockTime = blockTime + p.backOffTime(snap, header, p.val)
 	}
 	return blockTime
 }
 
 func (p *Parlia) blockTimeVerifyForRamanujanFork(snap *Snapshot, header, parent *types.Header) error {
 	if p.chainConfig.IsRamanujan(header.Number) {
-		if header.Time < parent.Time+p.config.Period+backOffTime(snap, header.Coinbase) {
+		if header.Time < parent.Time+p.config.Period+p.backOffTime(snap, header, header.Coinbase) {
 			return consensus.ErrFutureBlock
 		}
 	}