Add Eth1 Header Timestamp Check (#8771)

* add time check

* unit test

* fix

* Update beacon-chain/powchain/service.go

Co-authored-by: Raul Jordan <raul@prysmaticlabs.com>
Co-authored-by: terence tsao <terence@prysmaticlabs.com>

beacon-chain/powchain/service.go

@@ -59,17 +59,20 @@ var (
 	})
 )
 
-// time to wait before trying to reconnect with the eth1 node.
-var backOffPeriod = 15 * time.Second
-
-// Amount of times before we log the status of the eth1 dial attempt.
-var logThreshold = 8
-
-// period to log chainstart related information
-var logPeriod = 1 * time.Minute
-
-// error when eth1 node is not synced.
-var errNotSynced = errors.New("eth1 node is still syncing")
+var (
+	// time to wait before trying to reconnect with the eth1 node.
+	backOffPeriod = 15 * time.Second
+	// amount of times before we log the status of the eth1 dial attempt.
+	logThreshold = 8
+	// period to log chainstart related information
+	logPeriod = 1 * time.Minute
+	// threshold of how old we will accept an eth1 node's head to be.
+	eth1Threshold = 20 * time.Minute
+	// error when eth1 node is not synced.
+	errNotSynced = errors.New("eth1 node is still syncing")
+	// error when eth1 node is too far behind.
+	errFarBehind = errors.Errorf("eth1 head is more than %s behind from current wall clock time", eth1Threshold.String())
+)
 
 // ChainStartFetcher retrieves information pertaining to the chain start event
 // of the beacon chain for usage across various services.
@@ -535,7 +538,14 @@ func (s *Service) isEth1NodeSynced() (bool, error) {
 	if err != nil {
 		return false, err
 	}
-	return syncProg == nil, nil
+	if syncProg != nil {
+		return false, nil
+	}
+	head, err := s.eth1DataFetcher.HeaderByNumber(s.ctx, nil)
+	if err != nil {
+		return false, err
+	}
+	return !eth1HeadIsBehind(head.Time), nil
 }
 
 // Reconnect to eth1 node in case of any failure.
@@ -777,6 +787,11 @@ func (s *Service) run(done <-chan struct{}) {
 				s.retryETH1Node(err)
 				continue
 			}
+			if eth1HeadIsBehind(head.Time) {
+				log.WithError(errFarBehind).Debug("Could not get an up to date eth1 header")
+				s.retryETH1Node(errFarBehind)
+				continue
+			}
 			s.processBlockHeader(head)
 			s.handleETH1FollowDistance()
 			s.checkDefaultEndpoint()
@@ -972,3 +987,11 @@ func dedupEndpoints(endpoints []string) []string {
 	}
 	return newEndpoints
 }
+
+// Checks if the provided timestamp is beyond the prescribed bound from
+// the current wall clock time.
+func eth1HeadIsBehind(timestamp uint64) bool {
+	timeout := timeutils.Now().Add(-eth1Threshold)
+	// check that web3 client is syncing
+	return time.Unix(int64(timestamp), 0).Before(timeout)
+}

beacon-chain/powchain/service_test.go

@@ -278,7 +278,11 @@ func TestService_Eth1Synced(t *testing.T) {
 	web3Service = setDefaultMocks(web3Service)
 	web3Service.depositContractCaller, err = contracts.NewDepositContractCaller(testAcc.ContractAddr, testAcc.Backend)
 	require.NoError(t, err)
+	web3Service.eth1DataFetcher = &goodFetcher{backend: testAcc.Backend}
 
+	currTime := testAcc.Backend.Blockchain().CurrentHeader().Time
+	now := time.Now()
+	assert.NoError(t, testAcc.Backend.AdjustTime(now.Sub(time.Unix(int64(currTime), 0))))
 	testAcc.Backend.Commit()
 
 	synced, err := web3Service.isEth1NodeSynced()
@@ -615,3 +619,12 @@ func TestService_EnsureConsistentPowchainData(t *testing.T) {
 	assert.NotNil(t, eth1Data)
 	assert.Equal(t, true, eth1Data.ChainstartData.Chainstarted)
 }
+
+func TestTimestampIsChecked(t *testing.T) {
+	timestamp := uint64(time.Now().Unix())
+	assert.Equal(t, false, eth1HeadIsBehind(timestamp))
+
+	// Give an older timestmap beyond threshold.
+	timestamp = uint64(time.Now().Add(-eth1Threshold).Add(-1 * time.Minute).Unix())
+	assert.Equal(t, true, eth1HeadIsBehind(timestamp))
+}