LRU-based ordering buffer

src/event_check/epoch_check/epoch_check.go

@@ -15,8 +15,7 @@ var (
 )
 
 type DagReader interface {
-	GetEpoch() idx.Epoch
-	GetMembers() pos.Members
+	GetEpochMembers() (pos.Members, idx.Epoch)
 }
 
 // Check which require only current epoch info
@@ -33,10 +32,12 @@ func New(config *lachesis.DagConfig, reader DagReader) *Validator {
 }
 
 func (v *Validator) Validate(e *inter.Event) error {
-	if e.Epoch != v.reader.GetEpoch() {
+	// check epoch first, because validators group is known only for the current epoch
+	members, epoch := v.reader.GetEpochMembers()
+	if e.Epoch != epoch {
 		return ErrNotRecent
 	}
-	if _, ok := v.reader.GetMembers()[e.Creator]; !ok {
+	if _, ok := members[e.Creator]; !ok {
 		return ErrAuth
 	}
 	return nil

src/gossip/consensus.go

@@ -26,6 +26,8 @@ type Consensus interface {
 	GetEpoch() idx.Epoch
 	// GetMembers returns members of current epoch.
 	GetMembers() pos.Members
+	// GetEpochMembers atomically returns members of current epoch, and the epoch.
+	GetEpochMembers() (pos.Members, idx.Epoch)
 
 	// Bootstrap must be called (once) before calling other methods
 	Bootstrap(applyBlock inter.ApplyBlockFn)

src/gossip/poset_hook.go

@@ -49,6 +49,13 @@ func (hook *HookedEngine) GetEpoch() idx.Epoch {
 	return hook.engine.GetEpoch()
 }
 
+func (hook *HookedEngine) GetEpochMembers() (pos.Members, idx.Epoch) {
+	if hook.engine == nil {
+		return pos.Members{}, 1
+	}
+	return hook.engine.GetEpochMembers()
+}
+
 func (hook *HookedEngine) LastBlock() (idx.Block, hash.Event) {
 	if hook.engine == nil {
 		return idx.Block(1), hash.ZeroEvent

src/poset/epoch.go

@@ -90,6 +90,11 @@ func (p *Poset) GetMembers() pos.Members {
 	return p.Members.Copy()
 }
 
+// GetEpochMembers atomically returns members of current epoch, and the epoch.
+func (p *Poset) GetEpochMembers() (pos.Members, idx.Epoch) {
+	return p.GetMembers(), p.GetEpoch() // TODO atomic
+}
+
 // rootForklessCausesRoot returns hash of root B, if root A forkless causes root B.
 // Due to a fork, there may be many roots B with the same slot,
 // but forkless caused may be only one of them (if no more than 1/3n are Byzantine), with a specific hash.

src/poset/poset.go

@@ -55,12 +55,8 @@ func (p *Poset) LastBlock() (idx.Block, hash.Event) {
 // fills consensus-related fields: Frame, IsRoot, MedianTimestamp
 // returns nil if event should be dropped
 func (p *Poset) Prepare(e *inter.Event) *inter.Event {
-	if e.Epoch != p.EpochN {
-		p.Log.Info("Event is too old/too new", "event", e.String(), "epoch", e.Epoch, "expect", p.EpochN)
-		return nil
-	}
-	if _, ok := p.Members[e.Creator]; !ok {
-		p.Log.Warn("Creator isn't a member", "creator", e.Creator.String())
+	if err := epoch_check.New(&p.dag, p).Validate(e); err != nil {
+		p.Log.Error("Event prepare error", "err", err)
 		return nil
 	}
 	id := e.Hash() // remember, because we change event here
@@ -169,8 +165,8 @@ func (p *Poset) processKnownRoots() *election.ElectionRes {
 // Event order matter: parents first.
 // ProcessEvent is not safe for concurrent use.
 func (p *Poset) ProcessEvent(e *inter.Event) error {
-	if e.Epoch != p.EpochN {
-		return epoch_check.ErrNotRecent
+	if err := epoch_check.New(&p.dag, p).Validate(e); err != nil {
+		return err
 	}
 	p.Log.Debug("start event processing", "event", e.String())