Merge pull request #5737 from TheThingsNetwork/fix/class-b-fixes

Synchronize gateway time only with GPS timestamps

pkg/gatewayserver/io/io.go

@@ -22,6 +22,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/gogo/protobuf/types"
 	"go.thethings.network/lorawan-stack/v3/pkg/band"
 	"go.thethings.network/lorawan-stack/v3/pkg/config"
 	"go.thethings.network/lorawan-stack/v3/pkg/errorcontext"
@@ -241,27 +242,40 @@ func (c *Connection) HandleUp(up *ttnpb.UplinkMessage, frontendSync *FrontendClo
 	}
 
 	receivedAt := *ttnpb.StdTime(up.ReceivedAt)
+	gpsTime := func(mds []*ttnpb.RxMetadata) *types.Timestamp {
+		for _, md := range mds {
+			if gpsTime := md.GpsTime; gpsTime != nil {
+				return gpsTime
+			}
+		}
+		return nil
+	}(up.RxMetadata)
 
 	var ct scheduling.ConcentratorTime
 	switch {
 	case frontendSync != nil:
-		ct = c.scheduler.SyncWithGatewayConcentrator(frontendSync.Timestamp, frontendSync.ServerTime, frontendSync.GatewayTime, frontendSync.ConcentratorTime)
+		ct = c.scheduler.SyncWithGatewayConcentrator(
+			frontendSync.Timestamp,
+			frontendSync.ServerTime,
+			frontendSync.GatewayTime,
+			frontendSync.ConcentratorTime,
+		)
 		log.FromContext(c.ctx).WithFields(log.Fields(
 			"timestamp", frontendSync.Timestamp,
 			"concentrator_time", frontendSync.ConcentratorTime,
 			"server_time", frontendSync.ServerTime,
 			"gateway_time", frontendSync.GatewayTime,
 		)).Debug("Gateway clocks have been synchronized by the frontend")
-	case up.Settings.Time != nil:
-		gatewayTime := *ttnpb.StdTime(up.Settings.Time)
+	case gpsTime != nil:
+		gatewayTime := *ttnpb.StdTime(gpsTime)
 		ct = c.scheduler.SyncWithGatewayAbsolute(up.Settings.Timestamp, receivedAt, gatewayTime)
 		log.FromContext(c.ctx).WithFields(log.Fields(
 			"timestamp", up.Settings.Timestamp,
 			"concentrator_time", ct,
 			"server_time", receivedAt,
 			"gateway_time", gatewayTime,
 		)).Debug("Synchronized server and gateway absolute time")
-	case up.Settings.Time == nil:
+	case gpsTime == nil:
 		ct = c.scheduler.Sync(up.Settings.Timestamp, receivedAt)
 		log.FromContext(c.ctx).WithFields(log.Fields(
 			"timestamp", up.Settings.Timestamp,

pkg/gatewayserver/io/mock/frontend.go

@@ -56,7 +56,9 @@ func ConnectFrontend(ctx context.Context, ids *ttnpb.GatewayIdentifiers, server
 			case up := <-f.Up:
 				gatewayTime := time.Unix(0, 0).Add(time.Since(started))
 				up.ReceivedAt = ttnpb.ProtoTimePtr(time.Now())
-				up.Settings.Time = ttnpb.ProtoTimePtr(gatewayTime)
+				for _, md := range up.RxMetadata {
+					md.GpsTime = ttnpb.ProtoTimePtr(gatewayTime)
+				}
 				conn.HandleUp(up, nil)
 			case status := <-f.Status:
 				conn.HandleStatus(status)

pkg/networkserver/downlink.go

@@ -2096,14 +2096,14 @@ func (ns *NetworkServer) processDownlinkTask(ctx context.Context, consumerID str
 						case !slot.IsApplicationTime && slot.Class == ttnpb.Class_CLASS_C && time.Until(slot.Time) > 0:
 							logger.WithFields(log.Fields(
 								"slot_start", slot.Time,
-							)).Info("Class C downlink scheduling attempt performed too soon, retry attempt")
+							)).Debug("Class C downlink scheduling attempt performed too soon, retry attempt")
 							taskUpdateStrategy = nextDownlinkTask
 							return dev, nil, nil
 
 						case time.Until(slot.Time) > absoluteTimeSchedulingDelay+2*nsScheduleWindow():
 							logger.WithFields(log.Fields(
 								"slot_start", slot.Time,
-							)).Info("Class B/C downlink scheduling attempt performed too soon, retry attempt")
+							)).Debug("Class B/C downlink scheduling attempt performed too soon, retry attempt")
 							taskUpdateStrategy = nextDownlinkTask
 							return dev, nil, nil