all: protect self-mined block during reorg (#17656)

1 files changed, 44 insertions, 4 deletions

diff --git a/core/blockchain.go b/core/blockchain.go
index 7a3b09705..2f12ca62b 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -31,6 +31,7 @@ import (
 	"github.com/ethereum/go-ethereum/common/mclock"
 	"github.com/ethereum/go-ethereum/common/prque"
 	"github.com/ethereum/go-ethereum/consensus"
+	"github.com/ethereum/go-ethereum/consensus/clique"
 	"github.com/ethereum/go-ethereum/core/rawdb"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
@@ -128,13 +129,14 @@ type BlockChain struct {
 	validator Validator // block and state validator interface
 	vmConfig  vm.Config
 
-	badBlocks *lru.Cache // Bad block cache
+	badBlocks *lru.Cache                // Bad block cache
+	isLocalFn func(common.Address) bool // Function used to determine whether the block author is a local miner account.
 }
 
 // NewBlockChain returns a fully initialised block chain using information
 // available in the database. It initialises the default Ethereum Validator and
 // Processor.
-func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, chainConfig *params.ChainConfig, engine consensus.Engine, vmConfig vm.Config) (*BlockChain, error) {
+func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, chainConfig *params.ChainConfig, engine consensus.Engine, vmConfig vm.Config, isLocalFn func(common.Address) bool) (*BlockChain, error) {
 	if cacheConfig == nil {
 		cacheConfig = &CacheConfig{
 			TrieNodeLimit: 256 * 1024 * 1024,
@@ -154,6 +156,7 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, chainConfig *par
 		triegc:       prque.New(nil),
 		stateCache:   state.NewDatabase(db),
 		quit:         make(chan struct{}),
+		isLocalFn:    isLocalFn,
 		bodyCache:    bodyCache,
 		bodyRLPCache: bodyRLPCache,
 		blockCache:   blockCache,
@@ -967,8 +970,45 @@ func (bc *BlockChain) WriteBlockWithState(block *types.Block, receipts []*types.
 	reorg := externTd.Cmp(localTd) > 0
 	currentBlock = bc.CurrentBlock()
 	if !reorg && externTd.Cmp(localTd) == 0 {
-		// Split same-difficulty blocks by number, then at random
-		reorg = block.NumberU64() < currentBlock.NumberU64() || (block.NumberU64() == currentBlock.NumberU64() && mrand.Float64() < 0.5)
+		// 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() {
+			reorg = true
+		} else if block.NumberU64() == currentBlock.NumberU64() {
+			if _, ok := bc.engine.(*clique.Clique); ok {
+				// The reason we need to disable the self-reorg preserving for clique
+				// is it can be probable to introduce a deadlock.
+				//
+				// e.g. If there are 7 available signers
+				//
+				// r1   A
+				// r2     B
+				// r3       C
+				// r4         D
+				// r5   A      [X] F G
+				// r6    [X]
+				//
+				// In the round5, the inturn signer E is offline, so the worst case
+				// is A, F and G sign the block of round5 and reject the block of opponents
+				// and in the round6, the last available signer B is offline, the whole
+				// network is stuck.
+				reorg = mrand.Float64() < 0.5
+			} else {
+				currentAuthor, err := bc.engine.Author(currentBlock.Header())
+				if err != nil {
+					return NonStatTy, err
+				}
+				blockAuthor, err := bc.engine.Author(block.Header())
+				if err != nil {
+					return NonStatTy, err
+				}
+				var currentLocal, blockLocal bool
+				if bc.isLocalFn != nil {
+					currentLocal, blockLocal = bc.isLocalFn(currentAuthor), bc.isLocalFn(blockAuthor)
+				}
+				reorg = !currentLocal && (blockLocal || mrand.Float64() < 0.5)
+			}
+		}
 	}
 	if reorg {
 		// Reorganise the chain if the parent is not the head block