update README to remove restriction around region-based root topics

README.md

@@ -30,12 +30,9 @@ Meshtastic has [made a change to their MQTT server](https://meshtastic.org/blog/
 
 The most accurate resolution that conforms to this specification is 364 meters/1194 feet.
 
-Additionally, only the default [LoRa region](https://meshtastic.org/docs/configuration/radio/lora/#region)-based root topics (and all subtopics) are now monitored.
-
 #### To enable MQTT reporting
 - Enable the MQTT module, using all default settings, possibly with a custom root topic
   - View nodes around your area on the map to find MQTT topics being used
-  - Only the official [LoRa region](https://meshtastic.org/docs/configuration/radio/lora/#region)-based root topics (and all subtopics) are monitored
 - Configure your node to connect to wifi or otherwise connect to the internet
 - Enable MQTT uplink on your primary channel
   - It is not necessary, and not recommended unless you know what you're doing, to enable MQTT downlink

internal/meshtastic/node.go

@@ -12,6 +12,14 @@ const (
 	NeighborLimit = 100
 )
 
+func cleanFloat(f float32) float32 {
+	if f != f {
+		// IEEE 754 says that only NaNs satisfy f != f
+		return 0
+	}
+	return f
+}
+
 type NeighborInfo struct {
 	Snr     float32 `json:"snr,omitempty"`
 	Updated int64   `json:"updated"`
@@ -148,17 +156,17 @@ func (node *Node) Prune(seenByTtl, neighborTtl, metricsTtl, mapReportTtl int64)
 
 func (node *Node) UpdateDeviceMetrics(batteryLevel uint32, voltage, chUtil, airUtilTx float32, uptime uint32) {
 	node.BatteryLevel = batteryLevel
-	node.Voltage = voltage
+	node.Voltage = cleanFloat(voltage)
-	node.ChUtil = chUtil
+	node.ChUtil = cleanFloat(chUtil)
-	node.AirUtilTx = airUtilTx
+	node.AirUtilTx = cleanFloat(airUtilTx)
 	node.Uptime = uptime
 	node.LastDeviceMetrics = time.Now().Unix()
 }
 
 func (node *Node) UpdateEnvironmentMetrics(temperature, relativeHumidity, barometricPressure float32) {
-	node.Temperature = temperature
+	node.Temperature = cleanFloat(temperature)
-	node.RelativeHumidity = relativeHumidity
+	node.RelativeHumidity = cleanFloat(relativeHumidity)
-	node.BarometricPressure = barometricPressure
+	node.BarometricPressure = cleanFloat(barometricPressure)
 	node.LastEnvironmentMetrics = time.Now().Unix()
 }
 
@@ -176,7 +184,7 @@ func (node *Node) UpdateNeighborInfo(neighborNum uint32, snr float32) {
 		node.Neighbors = make(map[uint32]*NeighborInfo)
 	}
 	node.Neighbors[neighborNum] = &NeighborInfo{
-		Snr:     snr,
+		Snr:     cleanFloat(snr),
 		Updated: time.Now().Unix(),
 	}
 }