From 53e39d77acd5d18e7b27ad887f9867f074b634e8 Mon Sep 17 00:00:00 2001
From: AnilChinchwale <anil24593@gmail.com>
Date: Fri, 9 Nov 2018 16:42:45 +0530
Subject: [PATCH] fix error double validation

---
 consensus/errors.go    |  2 ++
 eth/fetcher/fetcher.go | 33 ++++++++++++---------------------
 2 files changed, 14 insertions(+), 21 deletions(-)

diff --git a/consensus/errors.go b/consensus/errors.go
index a005c5f63d..c4ff2de539 100644
--- a/consensus/errors.go
+++ b/consensus/errors.go
@@ -34,4 +34,6 @@ var (
 	// ErrInvalidNumber is returned if a block's number doesn't equal it's parent's
 	// plus one.
 	ErrInvalidNumber = errors.New("invalid block number")
+
+	ErrMissingValidatorSignature = errors.New("missing validator in header")
 )
diff --git a/eth/fetcher/fetcher.go b/eth/fetcher/fetcher.go
index 61b8772205..7c0746e105 100644
--- a/eth/fetcher/fetcher.go
+++ b/eth/fetcher/fetcher.go
@@ -142,7 +142,6 @@ type Fetcher struct {
 	queueChangeHook    func(common.Hash, bool) // Method to call upon adding or deleting a block from the import queue
 	fetchingHook       func([]common.Hash)     // Method to call upon starting a block (eth/61) or header (eth/62) fetch
 	completingHook     func([]common.Hash)     // Method to call upon starting a block body fetch (eth/62)
-	doubleValidateHook func(*types.Block) error
 	signHook           func(*types.Block) error
 	appendM2HeaderHook func(*types.Block) (*types.Block, error)
 }
@@ -654,33 +653,30 @@ func (f *Fetcher) insert(peer string, block *types.Block) {
 		// Quickly validate the header and propagate the block if it passes
 		switch err := f.verifyHeader(block.Header()); err {
 		case nil:
+			// All ok, quickly propagate to our peers
+			propBroadcastOutTimer.UpdateSince(block.ReceivedAt)
+			go f.broadcastBlock(block, true)
+		case consensus.ErrFutureBlock:
+		case consensus.ErrMissingValidatorSignature:
+			newBlock := block
 			if f.appendM2HeaderHook != nil {
-				if block, err = f.appendM2HeaderHook(block); err != nil {
+				if newBlock, err = f.appendM2HeaderHook(block); err != nil {
 					log.Error("Append m2 to block header fail", "err", err)
 					return
 				}
 			}
-
-			// All ok, quickly propagate to our peers
-			propBroadcastOutTimer.UpdateSince(block.ReceivedAt)
 			go f.broadcastBlock(block, true)
-
-		case consensus.ErrFutureBlock:
-			// Weird future block, don't fail, but neither propagate
-
+			if newBlock.Hash() == block.Hash() {
+				return
+			}
+			block = newBlock
+			propBroadcastOutTimer.UpdateSince(block.ReceivedAt)
 		default:
 			// Something went very wrong, drop the peer
 			log.Debug("Propagated block verification failed", "peer", peer, "number", block.Number(), "hash", hash, "err", err)
 			f.dropPeer(peer)
 			return
 		}
-		// Invoke the dv hook to run double validation layer
-		if f.doubleValidateHook != nil {
-			if err := f.doubleValidateHook(block); err != nil {
-				log.Error("Double validation failed", "err", err, "Discard this block!")
-				return
-			}
-		}
 
 		// Run the actual import and log any issues
 		if _, err := f.insertChain(types.Blocks{block}); err != nil {
@@ -756,11 +752,6 @@ func (f *Fetcher) forgetBlock(hash common.Hash) {
 	}
 }
 
-// Bind double validate hook before block imported into chain.
-func (f *Fetcher) SetDoubleValidateHook(doubleValidateHook func(*types.Block) error) {
-	f.doubleValidateHook = doubleValidateHook
-}
-
 // Bind double validate hook before block imported into chain.
 func (f *Fetcher) SetSignHook(signHook func(*types.Block) error) {
 	f.signHook = signHook