if PoS download block is within reach, determine VALID or INVALID (le…

…dgerwatch#4812)

* if PoS download is fast enough, determine VALID or INVALID

* more acceptable absolute value

* solved comments

* remove useless

* moved check in stage_headers

Co-authored-by: giuliorebuffo <giuliorebuffo@system76-pc.localdomain>

common/math/integer.go

@@ -96,3 +96,11 @@ func SafeMul(x, y uint64) (uint64, bool) {
 	hi, lo := bits.Mul64(x, y)
 	return lo, hi != 0
 }
+
+// GetAbsoluteDifference is a utility method that given 2 int64, it returns the absolute value of their difference in uint64 format.
+func AbsoluteDifference(x, y uint64) uint64 {
+	if x > y {
+		return x - y
+	}
+	return y - x
+}

common/math/integer_test.go

@@ -18,6 +18,8 @@ package math
 
 import (
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
 type operation byte
@@ -114,3 +116,10 @@ func TestMustParseUint64Panic(t *testing.T) {
 	}()
 	MustParseUint64("ggg")
 }
+
+func TestAbsoluteDifference(t *testing.T) {
+	x1 := uint64(99)
+	x2 := uint64(45)
+	assert.Equal(t, AbsoluteDifference(x1, x2), uint64(x1-x2))
+	assert.Equal(t, AbsoluteDifference(x2, x1), uint64(x1-x2))
+}

eth/stagedsync/stage_headers.go

@@ -19,6 +19,7 @@ import (
 	"github.com/ledgerwatch/erigon-lib/kv"
 	"github.com/ledgerwatch/erigon/common"
 	"github.com/ledgerwatch/erigon/common/dbutils"
+	"github.com/ledgerwatch/erigon/common/math"
 	"github.com/ledgerwatch/erigon/core/rawdb"
 	"github.com/ledgerwatch/erigon/core/types"
 	"github.com/ledgerwatch/erigon/ethdb/privateapi"
@@ -435,11 +436,24 @@ func handleNewPayload(
 		log.Info(fmt.Sprintf("[%s] New payload missing parent", s.LogPrefix()))
 		if test {
 			cfg.hd.BeaconRequestList.Remove(requestId)
+			return &engineapi.PayloadStatus{Status: remote.EngineStatus_SYNCING}, nil
+		}
+		cfg.hd.SetPoSDownloaderTip(headerHash)
+		schedulePoSDownload(requestId, header.ParentHash, headerNumber-1, s, cfg)
+		currentHeadNumber := rawdb.ReadCurrentBlockNumber(tx)
+		if currentHeadNumber != nil && math.AbsoluteDifference(*currentHeadNumber, headerNumber) < 32 {
+			// We try waiting until we finish downloading the PoS blocks if the distance from the head is enough,
+			// so that we will perform full validation.
+			time.Sleep(100 * time.Millisecond)
+			// If we downloaded the headers in time then save them and if we saved the current header, we return VALID
+			if cfg.hd.PosStatus() == headerdownload.Synced {
+				verifyAndSaveDownloadedPoSHeaders(tx, cfg, headerInserter)
+			} else {
+				return &engineapi.PayloadStatus{Status: remote.EngineStatus_SYNCING}, nil
+			}
 		} else {
-			cfg.hd.SetPoSDownloaderTip(headerHash)
-			schedulePoSDownload(requestId, header.ParentHash, headerNumber-1, s, cfg)
+			return &engineapi.PayloadStatus{Status: remote.EngineStatus_SYNCING}, nil
 		}
-		return &engineapi.PayloadStatus{Status: remote.EngineStatus_SYNCING}, nil
 	}
 
 	cfg.hd.BeaconRequestList.Remove(requestId)
@@ -471,6 +485,12 @@ func verifyAndSaveNewPoSHeader(
 	headerNumber := header.Number.Uint64()
 	headerHash := block.Hash()
 
+	bad, lastValidHash := cfg.hd.IsBadHeaderPoS(header.ParentHash)
+	if bad {
+		cfg.hd.ReportBadHeaderPoS(headerHash, lastValidHash)
+		return &engineapi.PayloadStatus{Status: remote.EngineStatus_INVALID, LatestValidHash: lastValidHash}, false, nil
+	}
+
 	if verificationErr := cfg.hd.VerifyHeader(header); verificationErr != nil {
 		log.Warn("Verification failed for header", "hash", headerHash, "height", headerNumber, "err", verificationErr)
 		cfg.hd.ReportBadHeaderPoS(headerHash, header.ParentHash)
@@ -636,7 +656,7 @@ func verifyAndSaveDownloadedPoSHeaders(tx kv.RwTx, cfg HeadersCfg, headerInserte
 		cfg.hd.BeaconRequestList.Remove(cfg.hd.RequestId())
 		cfg.hd.ReportBadHeaderPoS(cfg.hd.PoSDownloaderTip(), lastValidHash)
 	} else {
-		log.Info("PoS headers verified and saved", "requestId", cfg.hd.RequestId())
+		log.Info("PoS headers verified and saved", "requestId", cfg.hd.RequestId(), "fork head", lastValidHash)
 	}
 
 	cfg.hd.HeadersCollector().Close()
@@ -667,7 +687,7 @@ func handleInterrupt(interrupt engineapi.Interrupt, cfg HeadersCfg, tx kv.RwTx,
 		if interrupt == engineapi.Stopping {
 			cfg.hd.PayloadStatusCh <- engineapi.PayloadStatus{CriticalError: errors.New("server is stopping")}
 		}
-		if interrupt == engineapi.Synced {
+		if interrupt == engineapi.Synced && cfg.hd.HeadersCollector() != nil {
 			verifyAndSaveDownloadedPoSHeaders(tx, cfg, headerInserter)
 		}
 		if !useExternalTx {

turbo/engineapi/fork_validator.go

@@ -26,6 +26,7 @@ import (
 	"github.com/ledgerwatch/erigon/common"
 	"github.com/ledgerwatch/erigon/common/changeset"
 	"github.com/ledgerwatch/erigon/common/dbutils"
+	"github.com/ledgerwatch/erigon/common/math"
 	"github.com/ledgerwatch/erigon/core/rawdb"
 	"github.com/ledgerwatch/erigon/core/types"
 	"github.com/ledgerwatch/erigon/core/types/accounts"
@@ -60,14 +61,6 @@ type ForkValidator struct {
 	currentHeight uint64
 }
 
-// abs64 is a utility method that given an int64, it returns its absolute value in uint64.
-func abs64(n int64) uint64 {
-	if n < 0 {
-		return uint64(-n)
-	}
-	return uint64(n)
-}
-
 func NewForkValidatorMock(currentHeight uint64) *ForkValidator {
 	return &ForkValidator{
 		sideForksBlock: make(map[common.Hash]forkSegment),
@@ -226,7 +219,7 @@ func (fv *ForkValidator) ValidatePayload(tx kv.RwTx, header *types.Header, body
 	}
 
 	// if the block is not in range of maxForkDepth from head then we do not validate it.
-	if abs64(int64(fv.currentHeight)-header.Number.Int64()) > maxForkDepth {
+	if math.AbsoluteDifference(fv.currentHeight, header.Number.Uint64()) > maxForkDepth {
 		status = remote.EngineStatus_ACCEPTED
 		return
 	}
@@ -338,7 +331,7 @@ func (fv *ForkValidator) validateAndStorePayload(tx kv.RwTx, header *types.Heade
 // clean wipes out all outdated sideforks whose distance exceed the height of the head.
 func (fv *ForkValidator) clean() {
 	for hash, sb := range fv.sideForksBlock {
-		if abs64(int64(fv.currentHeight)-sb.header.Number.Int64()) > maxForkDepth {
+		if math.AbsoluteDifference(fv.currentHeight, sb.header.Number.Uint64()) > maxForkDepth {
 			delete(fv.sideForksBlock, hash)
 		}
 	}