protocol/meshcore: refactor decoding logic

protocol/meshcore/node.go

@@ -279,34 +279,45 @@ func (drv *companionDriver) handlePushFrame(b []byte) {
 }
 
 func (drv *companionDriver) handleRXData(b []byte) {
-	if len(b) < 2+minPacketSize {
-		return
-	}
-	if drv.packets == nil {
+	if drv.packets == nil && drv.rawPackets == nil {
 		return // not listening for packets, discard
 	}
 
-	now := time.Now().UTC()
-	packet := new(Packet)
-	if err := packet.UnmarshalBytes(b[2:]); err == nil {
-		packet.SNR = float64(b[0]) / 4
-		packet.RSSI = int8(b[1])
+	if len(b) < 2+minPacketSize {
+		return // too short
+	}
+
+	var (
+		now  = time.Now().UTC()
+		snr  = float64(b[0]) / 4
+		rssi = int8(b[1])
+	)
+
+	// Decode raw
+	if drv.rawPackets != nil {
 		select {
-		case drv.packets <- packet:
+		case drv.rawPackets <- &protocol.Packet{
+			Time:     now,
+			Protocol: protocol.MeshCore,
+			SNR:      snr,
+			RSSI:     rssi,
+			Raw:      b[2:],
+		}:
 		default:
-			log.Printf("meshcore: packet channel full, dropping packet")
+			log.Printf("meshcore: raw packet channel full, dropping packet")
 		}
-		if drv.rawPackets != nil {
+	}
+
+	// Decode payload
+	if drv.packets != nil {
+		packet := new(Packet)
+		if err := packet.UnmarshalBytes(b[2:]); err == nil {
+			packet.SNR = snr
+			packet.RSSI = rssi
 			select {
-			case drv.rawPackets <- &protocol.Packet{
-				Time:     now,
-				Protocol: "meshcore",
-				SNR:      packet.SNR,
-				RSSI:     packet.RSSI,
-				Raw:      packet.Raw,
-			}:
+			case drv.packets <- packet:
 			default:
-				log.Printf("meshcore: raw packet channel full, dropping packet")
+				log.Printf("meshcore: packet channel full, dropping packet")
 			}
 		}
 	}