Simple (POSIX-compliant) shell-script that pings a host-name once every minute and publishes the average roundtrip time (by default based on four pings) to MQTT.
Used on my DD-WRT router and access-points to monitor network/Internet performance. There's a ping sensor running in Home Assistant too, but its roundtrip times vary based on the load on the underlying (RPi 4) device. As such they are a less useful indication of overall network performance...
Requires JFFS (or some other form of persistent storage) and Entware installed on the DD-WRT unit.
opkg install mosquitto-client-nosslCopy the provided folder structure onto 📁 /jffs and update
📄 /jffs/etc/config/ping2mqtt.wanup with your MQTT hostname and the MQTT topic
to publish to (and optionally change the number of pings and the ping target).
Note that .wanup entails the script is run (i.e. pinging starts) whenever the
WAN connection goes up. In case of an access-point, using .startup might be
more appropriate (i.e. WAN up might never occur on those devices). See
https://wiki.dd-wrt.com/wiki/index.php/Script_Execution for more details.
./ping2mqtt.sh mqtt-host mqtt-topic [ping-host] [count]By default the ping-host is 8.8.8.8 (Google Public DNS) and count is 4.
The script will run indefinitely; pinging and publishing to MQTT (approximately) once per minute.
The script uses a (naive) locking approach to prevent spawning multiple
instances (as WAN up can occur an infinite number of times on a running DD-WRT
unit). A lock-file is written to /tmp (non-persistent storage; cleared at
reboot) and upon start the script will abort if the lock-file is present.
When receiving INT, HUP, TERM or EXIT the script will attempt to remove
the lock-file. This covers the most common termination scenarios and thus
entails the lock-file should be removed in those cases. The EXIT trap
specifically should ensure the script cleans up after itself in case one of the
commands it attempts to execute fails.
The below configuration provides public (i.e., no authorisation required) read-only access to a limited set of metrics.
Don't enable SNMP in the DD-WRT GUI. Instead, copy
📄 snmpd.conf to 📂 /jffs/etc/snmp (this
assume JFFS is available). Start the snmpd daemon via the GUI; add the below
to the startup script (under Administration / Commands):
snmpd -c /jffs/etc/snmp/snmpd.confThe below table provides an overview of the metrics currently used in Home Assistant.
| Type | Description | OID |
|---|---|---|
| CPU | 1-minute load | 1.3.6.1.4.1.2021.10.1.3.1 |
| Memory | Real available (KiB) | 1.3.6.1.4.1.2021.4.6.0 |
| Memory | Cached (KiB) | 1.3.6.1.4.1.2021.4.14.0 |
| Memory | Buffer (KiB) | 1.3.6.1.4.1.2021.4.15.0 |
| Network | WAN in (octets) | 1.3.6.1.2.1.2.2.1.10.5 |
| Network | WAN out (octets) | 1.3.6.1.2.1.2.2.1.16.5 |
To come to an approximation of the percentage "memory available", sum the three
memory metrics in the above table (real, cached and buffer) and compute
that as a fraction of the total memory installed in the system.