[NOD-727] Do not allow delayed blocks from RPC. (#623)

* [NOD-727] Do not allow delayed blocks from RPC.

* [NOD-727] Refactor sentFromRPC -> DisallowDelay

* [NOD-727] Clarify comment; Clarify error message.

* [NOD-727] Change error message.

blockdag/error.go

@@ -217,6 +217,10 @@ const (
 	// ErrInvalidParentsRelation indicates that one of the parents of a block
 	// is also an ancestor of another parent
 	ErrInvalidParentsRelation
+
+	// ErrDelayedBlockIsNotAllowed indicates that a block with a delayed timestamp was
+	// submitted with BFDisallowDelay flag raised.
+	ErrDelayedBlockIsNotAllowed
 )
 
 // Map of ErrorCode values back to their constant names for pretty printing.
@@ -264,6 +268,7 @@ var errorCodeStrings = map[ErrorCode]string{
 	ErrInvalidPayload:            "ErrInvalidPayload",
 	ErrInvalidPayloadHash:        "ErrInvalidPayloadHash",
 	ErrInvalidParentsRelation:    "ErrInvalidParentsRelation",
+	ErrDelayedBlockIsNotAllowed:  "ErrDelayedBlockIsNotAllowed",
 }
 
 // String returns the ErrorCode as a human-readable name.

blockdag/error_test.go

@@ -58,6 +58,7 @@ func TestErrorCodeStringer(t *testing.T) {
 		{ErrInvalidPayload, "ErrInvalidPayload"},
 		{ErrInvalidPayloadHash, "ErrInvalidPayloadHash"},
 		{ErrInvalidParentsRelation, "ErrInvalidParentsRelation"},
+		{ErrDelayedBlockIsNotAllowed, "ErrDelayedBlockIsNotAllowed"},
 		{0xffff, "Unknown ErrorCode (65535)"},
 	}
 

blockdag/process.go

@@ -45,6 +45,10 @@ const (
 	// in the block index but was never fully processed
 	BFWasStored
 
+	// BFDisallowDelay is set to indicate that a delayed block should be rejected.
+	// This is used for the case where a block is submitted through RPC.
+	BFDisallowDelay
+
 	// BFNone is a convenience value to specifically indicate no flags.
 	BFNone BehaviorFlags = 0
 )
@@ -146,6 +150,7 @@ func (dag *BlockDAG) ProcessBlock(block *util.Block, flags BehaviorFlags) (isOrp
 func (dag *BlockDAG) processBlockNoLock(block *util.Block, flags BehaviorFlags) (isOrphan bool, isDelayed bool, err error) {
 	isAfterDelay := flags&BFAfterDelay == BFAfterDelay
 	wasBlockStored := flags&BFWasStored == BFWasStored
+	disallowDelay := flags&BFDisallowDelay == BFDisallowDelay
 
 	blockHash := block.Hash()
 	log.Tracef("Processing block %s", blockHash)
@@ -174,6 +179,11 @@ func (dag *BlockDAG) processBlockNoLock(block *util.Block, flags BehaviorFlags)
 			return false, false, err
 		}
 
+		if delay != 0 && disallowDelay {
+			str := fmt.Sprintf("Cannot process blocks beyond the allowed time offset while the BFDisallowDelay flag is raised %s", blockHash)
+			return false, true, ruleError(ErrDelayedBlockIsNotAllowed, str)
+		}
+
 		if delay != 0 {
 			err = dag.addDelayedBlock(block, delay)
 			if err != nil {

netsync/manager.go

@@ -867,7 +867,7 @@ func (sm *SyncManager) limitHashMap(m map[daghash.Hash]struct{}, limit int) {
 
 func (sm *SyncManager) handleProcessBlockMsg(msg processBlockMsg) (isOrphan bool, err error) {
 	isOrphan, isDelayed, err := sm.dag.ProcessBlock(
-		msg.block, msg.flags)
+		msg.block, msg.flags|blockdag.BFDisallowDelay)
 	if err != nil {
 		return false, err
 	}