basicstation: Fix tx acknowledgement and set Class-A RX2 params.

The BasicStation does not send a dntxed when the DevEUI is set to
"00-00-00-00-00-00-00-00".

Author: brocaar

internal/backend/basicstation/backend_test.go

@@ -344,7 +344,7 @@ func (ts *BackendTestSuite) TestSendDownlinkFrame() {
 
 	assert.Equal(structs.DownlinkFrame{
 		MessageType: structs.DownlinkMessage,
-		DevEui:      "00-00-00-00-00-00-00-00",
+		DevEui:      "01-01-01-01-01-01-01-01",
 		DC:          0,
 		DIID:        1234,
 		Priority:    1,

internal/backend/basicstation/structs/downlink_message.go

@@ -41,13 +41,13 @@ func DownlinkFrameFromProto(loraBand band.Band, pb gw.DownlinkFrame) (DownlinkFr
 		return DownlinkFrame{}, errors.New("items must contain at least one item")
 	}
 
-	// TODO: implement for rx1 and rx2 parameters when there are two downlink items.
+	// We assume this is for RX1
 	item := pb.Items[0]
 
 	out := DownlinkFrame{
 		MessageType: DownlinkMessage,
 		Priority:    1,                         // not (yet) available through gw.DownlinkFrame
-		DevEui:      "00-00-00-00-00-00-00-00", // set to blank EUI
+		DevEui:      "01-01-01-01-01-01-01-01", // set to fake DevEUI (setting it to 0 causes the BasicStation to not send acks, see https://github.com/lorabasics/basicstation/issues/71).
 		DIID:        pb.Token,
 		PDU:         hex.EncodeToString(item.PhyPayload),
 	}
@@ -137,5 +137,39 @@ func DownlinkFrameFromProto(loraBand band.Band, pb gw.DownlinkFrame) (DownlinkFr
 		return out, fmt.Errorf("unexpected downlink timing: %s", item.GetTxInfo().Timing)
 	}
 
+	// We assume this is the RX2.
+	if len(pb.Items) == 2 {
+		item := pb.Items[1]
+
+		if item.GetTxInfo().GetDelayTimingInfo() != nil {
+			if modInfo := item.GetTxInfo().GetLoraModulationInfo(); modInfo != nil {
+				dr, err := loraBand.GetDataRateIndex(false, band.DataRate{
+					Modulation:   band.LoRaModulation,
+					SpreadFactor: int(modInfo.SpreadingFactor),
+					Bandwidth:    int(modInfo.Bandwidth),
+				})
+				if err != nil {
+					return out, errors.Wrap(err, "get data-rate index error")
+				}
+
+				out.RX2Freq = &item.GetTxInfo().Frequency
+				out.RX2DR = &dr
+			}
+
+			if modInfo := item.GetTxInfo().GetFskModulationInfo(); modInfo != nil {
+				dr, err := loraBand.GetDataRateIndex(false, band.DataRate{
+					Modulation: band.FSKModulation,
+					BitRate:    int(modInfo.Datarate),
+				})
+				if err != nil {
+					return out, errors.Wrap(err, "get data-rate index error")
+				}
+
+				out.RX2Freq = &item.GetTxInfo().Frequency
+				out.RX2DR = &dr
+			}
+		}
+	}
+
 	return out, nil
 }

internal/backend/basicstation/structs/downlink_message_test.go

@@ -14,9 +14,11 @@ import (
 
 func TestDownlinkFrameFromProto(t *testing.T) {
 	delay1 := 1
+	dr1 := 1
 	dr2 := 2
 	dr7 := 7
 	freq := uint32(868100000)
+	freq2 := uint32(868200000)
 	rCtx := uint64(3)
 	xTime := uint64(4)
 	gpsTime := uint64(time.Second / time.Microsecond)
@@ -56,11 +58,34 @@ func TestDownlinkFrameFromProto(t *testing.T) {
 							Context: []byte{0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 4},
 						},
 					},
+					{
+						PhyPayload: []byte{1, 2, 3, 4},
+						TxInfo: &gw.DownlinkTXInfo{
+							Frequency:  868200000,
+							Power:      14,
+							Modulation: common.Modulation_LORA,
+							ModulationInfo: &gw.DownlinkTXInfo_LoraModulationInfo{
+								LoraModulationInfo: &gw.LoRaModulationInfo{
+									Bandwidth:             125,
+									SpreadingFactor:       11,
+									CodeRate:              "4/5",
+									PolarizationInversion: true,
+								},
+							},
+							Timing: gw.DownlinkTiming_DELAY,
+							TimingInfo: &gw.DownlinkTXInfo_DelayTimingInfo{
+								DelayTimingInfo: &gw.DelayTimingInfo{
+									Delay: ptypes.DurationProto(time.Second * 2),
+								},
+							},
+							Context: []byte{0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 4},
+						},
+					},
 				},
 			},
 			Out: DownlinkFrame{
 				MessageType: DownlinkMessage,
-				DevEui:      "00-00-00-00-00-00-00-00",
+				DevEui:      "01-01-01-01-01-01-01-01",
 				DC:          0,
 				DIID:        1234,
 				Priority:    1,
@@ -70,6 +95,8 @@ func TestDownlinkFrameFromProto(t *testing.T) {
 				RxDelay:     &delay1,
 				RX1DR:       &dr2,
 				RX1Freq:     &freq,
+				RX2DR:       &dr1,
+				RX2Freq:     &freq2,
 			},
 		},
 		{
@@ -102,7 +129,7 @@ func TestDownlinkFrameFromProto(t *testing.T) {
 			},
 			Out: DownlinkFrame{
 				MessageType: DownlinkMessage,
-				DevEui:      "00-00-00-00-00-00-00-00",
+				DevEui:      "01-01-01-01-01-01-01-01",
 				DC:          0,
 				DIID:        1234,
 				Priority:    1,
@@ -147,7 +174,7 @@ func TestDownlinkFrameFromProto(t *testing.T) {
 			},
 			Out: DownlinkFrame{
 				MessageType: DownlinkMessage,
-				DevEui:      "00-00-00-00-00-00-00-00",
+				DevEui:      "01-01-01-01-01-01-01-01",
 				DC:          1,
 				DIID:        1234,
 				Priority:    1,
@@ -187,7 +214,7 @@ func TestDownlinkFrameFromProto(t *testing.T) {
 			},
 			Out: DownlinkFrame{
 				MessageType: DownlinkMessage,
-				DevEui:      "00-00-00-00-00-00-00-00",
+				DevEui:      "01-01-01-01-01-01-01-01",
 				DC:          2,
 				DIID:        1234,
 				Priority:    1,