ESP8266 rebooting (Exception (3)) with long oid request about arduino_snmp HOT 3 CLOSED

@fcqpl said:

I'm getting ESP8266 resetting while doing snmp get with long oid.
Example OID: 1.3.6.1.2.1.1.5.0.4.1.1.3.4.5.67.2.21.2.23.3.4.5.5.6.2.1222.3
I'm not using long oids in my application, but I connected LibreNMS in which I wanted to keep charts. During execution of Device Discovery, ESP8266 resets multiple times.
Example OID from Librenms discovery: 1.3.6.1.4.1.8072.1.3.2.3.1.2.6.100.105.115.116.114.111

Arduino_SNMP should dropping packets with long oid, but i don't know where to implement it.

I am working with the developer @0neblock on this same issue on my ESP32 and wanted to reach out to you with a suggestion that is working at the moment for me. I am using both Observium and LibreNMS on testing a solution and I noted that if I disable UCD-SNMP-MIB checking within the Observium \ device \ properties \ MIBs section (LibreNMS should have the same section) then the crash stops.

That disables the extended UCD-SNMP-MIB and then I have no issues. This is not a fix but it does get me to the next step of reliable operation so I can continue testing and building instead of endless crashing. Hope it helps in some small way.

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I believe the crashes with long OIDs is caused by a fixed size buffer which only allows max of 50 characters for the OID. I believe an OID can be up to 128. I'll submit a PR for this change shortly.

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@shortbloke I can confirm that making the suggested changes to the BER.h file manually has fixed the issue. Much appreciated!

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