nicer check using Time objects

chain/sub/incoming.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"sync"
+	"time"
 
 	"golang.org/x/xerrors"
 
@@ -368,9 +369,8 @@ func (bv *BlockValidator) decodeAndCheckBlock(msg *pubsub.Message) (*types.Block
 func (bv *BlockValidator) isChainNearSynced() bool {
 	ts := bv.chain.GetHeaviestTipSet()
 	timestamp := ts.MinTimestamp()
-	now := build.Clock.Now().Unix()
-	cutoff := uint64(now) - uint64(6*3600) // 6 hours
-	return timestamp > cutoff
+	timestampTime := time.Unix(int64(timestamp), 0)
+	return build.Clock.Since(timestampTime) < 6*time.Hour
 }
 
 func (bv *BlockValidator) validateMsgMeta(ctx context.Context, msg *types.BlockMsg) error {