VRP - Fix SSID Client count

[PipoCanaja]

This PR fixes information that was misplaced:
Back when I added support for VRP wireless, only "per radio and per SSID" count was available. Resulting in a huge amount of sensors. And at that time no aggregation of wireless sensors was possible. So at the end of the day, it was impossible to visualize the amount of clients per SSID at all.

Now, both aspects improved:

• We now have "per band and per SSID" which mean, today, twice as much data as expected for SSID client Count. So one sensor for 5Ghz and one for 2.4 Ghz.
• We can aggregate those using wireless-sensors (creating a 3rd "Total" sensor for each SSID)

The number of clients per radio is of course still available in the AccessPoints screen.

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[murrant]

snmpwalk_group() can accept an input array so you don't have to merge them. Also, it doesn't look like this data is used for any other sensor, so no need to cache them, that just wastes ram.

[PipoCanaja]

Makes sense. Will fix that.

[PipoCanaja]

Hum, snmpwalk_group only works with one OID, not an array. So the merge is still mandatory. But at least caching will be avoided.

[murrant]

nope, like this (changed to snmpwalk_cache_oid because group does not allow specifying snmp flags):

        $staTable = snmpwalk_cache_oid($this->getDeviceArray(), 'hwWlanSsid', [], 'HUAWEI-WLAN-VAP-MIB', null, '-OQUsb');
        $staTable = snmpwalk_cache_oid($this->getDeviceArray(), 'hwWlanSsid2gStaCnt', $staTable, 'HUAWEI-WLAN-VAP-MIB', null, '-OQUsb');
        $staTable = snmpwalk_cache_oid($this->getDeviceArray(), 'hwWlanSsid2gStaCnt', $staTable, 'HUAWEI-WLAN-VAP-MIB', null, '-OQUsb');

[murrant]

See how passing the same array inserts data into it. Much better than a recursive merge.

[murrant]

All index values must have an oid you can access from. Look at the snmp table, it is a member of the table. Does it return nothing from the captured data or the actual device? Because it would not be in the captured data.

[PipoCanaja]

Not this one. The index itself cannot be walked. And it is a string index.
So the only way to grab the index is to split the OID in the snmpwalk result. But doing so will only give me the index in numerical or in string (depending how I do the walk). And then I'll need to convert it to the other form (either numerical to string or string to OID).

[PipoCanaja]

Documentation confirms the behaviour. The hwWlanSsid is the index, and cannot be walked by itself. So no other choice than extracting (and converting) the index from num to str or the opposite.

OID	Object Name	Syntax	Max Access	Description	Implemented Specifications
1.3.6.1.4.1.2011.6.139.17.1.2.1.1	hwWlanSsid	OCTET STRING	not-accessible	This object indicates the table index.	This object is implemented as defined in the corresponding MIB file.
1.3.6.1.4.1.2011.6.139.17.1.2.1.2	hwWlanSsid2gStaCnt	Integer32	read-only	This object indicates the number of users at 2.4G frequency band.	This object is implemented as defined in the corresponding MIB file.

[murrant]

Fun.

[PipoCanaja]

Annoyingly fun :)

[librenms-bot]

This pull request has been mentioned on LibreNMS Community. There might be relevant details there:

https://community.librenms.org/t/21-4-0-changelog/15528/1