From a0d9e5f2c716781f72700f5e68c326abfee9e7dc Mon Sep 17 00:00:00 2001
From: fudongbai <296179868@qq.com>
Date: Thu, 5 Aug 2021 21:42:21 +0800
Subject: [PATCH 1/2] change Canon chain condition

---
 consensus/consensus.go     |  1 +
 consensus/parlia/parlia.go | 28 ++++++++++++++++++++++++++++
 core/blockchain.go         |  6 +++++-
 miner/worker.go            | 11 +++++++++++
 4 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/consensus/consensus.go b/consensus/consensus.go
index 69a5f2f2ef..fc161390f9 100644
--- a/consensus/consensus.go
+++ b/consensus/consensus.go
@@ -140,4 +140,5 @@ type PoSA interface {
 	IsSystemTransaction(tx *types.Transaction, header *types.Header) (bool, error)
 	IsSystemContract(to *common.Address) bool
 	EnoughDistance(chain ChainReader, header *types.Header) bool
+	IsLocalBlock(header *types.Header) bool
 }
diff --git a/consensus/parlia/parlia.go b/consensus/parlia/parlia.go
index 62d109848f..14304fe2bc 100644
--- a/consensus/parlia/parlia.go
+++ b/consensus/parlia/parlia.go
@@ -882,6 +882,34 @@ func (p *Parlia) EnoughDistance(chain consensus.ChainReader, header *types.Heade
 	return snap.enoughDistance(p.val, header)
 }
 
+func (p *Parlia) IsLocalBlock(header *types.Header) bool {
+	return p.val == header.Coinbase
+}
+
+func (p *Parlia) SignRecently(chain consensus.ChainReader, parent *types.Header) (bool, error) {
+	snap, err := p.snapshot(chain, parent.Number.Uint64(), parent.ParentHash, nil)
+	if err != nil {
+		return true, err
+	}
+
+	// Bail out if we're unauthorized to sign a block
+	if _, authorized := snap.Validators[p.val]; !authorized {
+		return true, errUnauthorizedValidator
+	}
+
+	// If we're amongst the recent signers, wait for the next block
+	number := parent.Number.Uint64() + 1
+	for seen, recent := range snap.Recents {
+		if recent == p.val {
+			// Signer is among recents, only wait if the current block doesn't shift it out
+			if limit := uint64(len(snap.Validators)/2 + 1); number < limit || seen > number-limit {
+				return true, nil
+			}
+		}
+	}
+	return false, nil
+}
+
 // CalcDifficulty is the difficulty adjustment algorithm. It returns the difficulty
 // that a new block should have based on the previous blocks in the chain and the
 // current signer.
diff --git a/core/blockchain.go b/core/blockchain.go
index 3cc44fc4e5..8b8b36b081 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -1578,8 +1578,12 @@ func (bc *BlockChain) writeBlockWithState(block *types.Block, receipts []*types.
 	if !reorg && externTd.Cmp(localTd) == 0 {
 		// Split same-difficulty blocks by number, then preferentially select
 		// the block generated by the local miner as the canonical block.
-		if block.NumberU64() < currentBlock.NumberU64() {
+		if block.NumberU64() < currentBlock.NumberU64() || block.Time() < currentBlock.Time() {
 			reorg = true
+		} else if p, ok := bc.engine.(consensus.PoSA); ok {
+			if p.IsLocalBlock(currentBlock.Header()) {
+				reorg = true
+			}
 		} else if block.NumberU64() == currentBlock.NumberU64() {
 			var currentPreserve, blockPreserve bool
 			if bc.shouldPreserve != nil {
diff --git a/miner/worker.go b/miner/worker.go
index b93b8752af..984af7baaf 100644
--- a/miner/worker.go
+++ b/miner/worker.go
@@ -389,6 +389,17 @@ func (w *worker) newWorkLoop(recommit time.Duration) {
 			}
 			clearPending(head.Block.NumberU64())
 			timestamp = time.Now().Unix()
+			if p, ok := w.engine.(*parlia.Parlia); ok {
+				signedRecent, err := p.SignRecently(w.chain, head.Block.Header())
+				if err != nil {
+					log.Info("Not allowed to propose block", "err", err)
+					continue
+				}
+				if signedRecent {
+					log.Info("Signed recently, must wait")
+					continue
+				}
+			}
 			commit(true, commitInterruptNewHead)
 
 		case <-timer.C:

From 530ee7b3cd7767b18cff2b5f67cb8078633685a9 Mon Sep 17 00:00:00 2001
From: fudongbai <296179868@qq.com>
Date: Mon, 9 Aug 2021 13:46:02 +0800
Subject: [PATCH 2/2] resolve comment

---
 core/blockchain.go | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/core/blockchain.go b/core/blockchain.go
index 8b8b36b081..66f37914df 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -1580,10 +1580,8 @@ func (bc *BlockChain) writeBlockWithState(block *types.Block, receipts []*types.
 		// the block generated by the local miner as the canonical block.
 		if block.NumberU64() < currentBlock.NumberU64() || block.Time() < currentBlock.Time() {
 			reorg = true
-		} else if p, ok := bc.engine.(consensus.PoSA); ok {
-			if p.IsLocalBlock(currentBlock.Header()) {
-				reorg = true
-			}
+		} else if p, ok := bc.engine.(consensus.PoSA); ok && p.IsLocalBlock(currentBlock.Header()) {
+			reorg = true
 		} else if block.NumberU64() == currentBlock.NumberU64() {
 			var currentPreserve, blockPreserve bool
 			if bc.shouldPreserve != nil {