Function downlinkPathsFromMetadata

pkg/networkserver/downlink.go:744–783

(
	settings *ttnpb.MACState_UplinkMessage_TxSettings, mds []*ttnpb.MACState_UplinkMessage_RxMetadata,
)

}

func downlinkPathsFromMetadata(
	settings *ttnpb.MACState_UplinkMessage_TxSettings, mds []*ttnpb.MACState_UplinkMessage_RxMetadata,
) []downlinkPath {
	mds = append(mds[:0:0], mds...)
	sort.SliceStable(mds, buildMetadataComparator(settings, mds))
	head := make([]downlinkPath, 0, len(mds))
	body := make([]downlinkPath, 0, len(mds))
	tail := make([]downlinkPath, 0, len(mds))
	for _, md := range mds {
		if len(md.UplinkToken) == 0 || md.DownlinkPathConstraint == ttnpb.DownlinkPathConstraint_DOWNLINK_PATH_CONSTRAINT_NEVER {
			continue
		}
		path := downlinkPath{
			DownlinkPath: &ttnpb.DownlinkPath{
				Path: &ttnpb.DownlinkPath_UplinkToken{
					UplinkToken: md.UplinkToken,
				},
			},
		}
		switch {
		case md.PacketBroker != nil:
			path.GatewayIdentifiers = packetbroker.GatewayIdentifiers
			tail = append(tail, path)
		case md.Relay != nil:
			path.GatewayIdentifiers = relayspec.GatewayIdentifiers
			tail = append(tail, path)
		default:
			path.GatewayIdentifiers = md.GatewayIds
			switch md.DownlinkPathConstraint {
			case ttnpb.DownlinkPathConstraint_DOWNLINK_PATH_CONSTRAINT_NONE:
				head = append(head, path)
			case ttnpb.DownlinkPathConstraint_DOWNLINK_PATH_CONSTRAINT_PREFER_OTHER:
				body = append(body, path)
			}
		}
	}
	res := append(head, body...)
	res = append(res, tail...)
	return res
}

func downlinkPathsFromRecentUplinks(ups ...*ttnpb.MACState_UplinkMessage) []downlinkPath {
	for i := len(ups) - 1; i >= 0; i-- {