Set UplinkRxInfo location in case of rxpk + stat.

This is useful in case ChirpStack is configured to allow data from
unknown gateways, and the UDP frame contains both a rkpk and stat
payload. In this case, if the location is set in the stat payload, it
can be set to the UplinkRxInfo struct.

Author: brocaar

internal/backend/semtechudp/packets/push_data.go

@@ -91,15 +91,15 @@ func (p PushDataPacket) GetUplinkFrames(skipCRCCheck bool, FakeRxInfoTime bool)
 		}
 
 		if len(p.Payload.RXPK[i].RSig) == 0 {
-			frame, err := getUplinkFrame(p.GatewayMAC, p.Payload.RXPK[i], FakeRxInfoTime)
+			frame, err := getUplinkFrame(p.GatewayMAC, p.Payload.Stat, p.Payload.RXPK[i], FakeRxInfoTime)
 			if err != nil {
 				return nil, errors.Wrap(err, "backend/semtechudp/packets: get uplink frame error")
 			}
 			frame.RxInfo.UplinkId = uint32(p.RandomToken)
 			frames = append(frames, frame)
 		} else {
 			for j := range p.Payload.RXPK[i].RSig {
-				frame, err := getUplinkFrame(p.GatewayMAC, p.Payload.RXPK[i], FakeRxInfoTime)
+				frame, err := getUplinkFrame(p.GatewayMAC, p.Payload.Stat, p.Payload.RXPK[i], FakeRxInfoTime)
 				if err != nil {
 					return nil, errors.Wrap(err, "backend/semtechudp/packets: get uplink frame error")
 				}
@@ -127,7 +127,7 @@ func setUplinkFrameRSig(frame *gw.UplinkFrame, rxPK RXPK, rSig RSig) *gw.UplinkF
 	return frame
 }
 
-func getUplinkFrame(gatewayID lorawan.EUI64, rxpk RXPK, FakeRxInfoTime bool) (*gw.UplinkFrame, error) {
+func getUplinkFrame(gatewayID lorawan.EUI64, stat *Stat, rxpk RXPK, FakeRxInfoTime bool) (*gw.UplinkFrame, error) {
 	frame := gw.UplinkFrame{
 		PhyPayload: rxpk.Data,
 		TxInfo: &gw.UplinkTxInfo{
@@ -145,6 +145,18 @@ func getUplinkFrame(gatewayID lorawan.EUI64, rxpk RXPK, FakeRxInfoTime bool) (*g
 		},
 	}
 
+	// If a Stat is present and it contains a location, immediately set the location for this uplink.
+	// This is for example the case of Helium, where the UDP frame contains both a rxpk and stat
+	// payload to provide additional gateway context.
+	if stat != nil && (stat.Lati != 0 || stat.Long != 0 || stat.Alti != 0) {
+		frame.RxInfo.Location = &common.Location{
+			Latitude:  stat.Lati,
+			Longitude: stat.Long,
+			Altitude:  float64(stat.Alti),
+			Source:    common.LocationSource_GPS,
+		}
+	}
+
 	switch rxpk.Stat {
 	case 1:
 		frame.RxInfo.CrcStatus = gw.CRCStatus_CRC_OK

internal/backend/semtechudp/packets/push_data_test.go

@@ -554,6 +554,74 @@ func TestGetUplinkFrame(t *testing.T) {
 				},
 			},
 		},
+		{
+			Name: "uplink with stat (with location)",
+			PushDataPacket: PushDataPacket{
+				GatewayMAC:      lorawan.EUI64{1, 2, 3, 4, 5, 6, 7, 8},
+				ProtocolVersion: ProtocolVersion2,
+				Payload: PushDataPayload{
+					RXPK: []RXPK{
+						{
+							Time: &ctNow,
+							Tmst: 1000000,
+							Freq: 868.3,
+							Brd:  2,
+							Chan: 1,
+							RFCh: 3,
+							Stat: 1,
+							Modu: "LORA",
+							DatR: DatR{LoRa: "SF12BW500"},
+							CodR: "4/5",
+							RSSI: -60,
+							LSNR: 5.5,
+							Size: 5,
+							Data: []byte{1, 2, 3, 4, 5},
+						},
+					},
+					Stat: &Stat{
+						Lati: 1.1,
+						Long: 1.2,
+						Alti: 10,
+					},
+				},
+			},
+			UplinkFrames: []*gw.UplinkFrame{
+				{
+					PhyPayload: []byte{1, 2, 3, 4, 5},
+					TxInfo: &gw.UplinkTxInfo{
+						Frequency: 868300000,
+						Modulation: &gw.Modulation{
+							Parameters: &gw.Modulation_Lora{
+								Lora: &gw.LoraModulationInfo{
+									Bandwidth:             500000,
+									SpreadingFactor:       12,
+									CodeRate:              gw.CodeRate_CR_4_5,
+									PolarizationInversion: false,
+								},
+							},
+						},
+					},
+					RxInfo: &gw.UplinkRxInfo{
+						GatewayId: "0102030405060708",
+						Time:      pbTime,
+						Rssi:      -60,
+						Snr:       5.5,
+						Channel:   1,
+						RfChain:   3,
+						Board:     2,
+						Antenna:   0,
+						Context:   []byte{0x00, 0x0f, 0x42, 0x40},
+						CrcStatus: gw.CRCStatus_CRC_OK,
+						Location: &common.Location{
+							Latitude:  1.1,
+							Longitude: 1.2,
+							Altitude:  10,
+							Source:    common.LocationSource_GPS,
+						},
+					},
+				},
+			},
+		},
 	}
 
 	for _, test := range testTable {