Dynamic loadable module not working with compiled smpd V7.5.3

[Jose T. <j.t...@uv...>]

Hello

I have a weird situation with a compiled snmpd V7.5.3 and not able to find out what's going on.

I have a linux system. At first instance I used the "official" snmpd (sudo apt-get install snmpd ... ) and added a reduced set of OIDs from an own MIB (with several scalar OIDs) in a dynamic loadable module following the steps of the corresponding tutorial. It worked fine. So far so good.

Next, I had to add more OIDs that belonged to a table. I followed the corresponding steps to add the table and got it working. In this case, the functionality for that table was added as a subagent. So at this moment everything was fine. But I realized that one OID from the table was an OCTET STRING which size was 65536 and in my case it only worked up to 1472 bytes. I investigated a little and I realized I had to recompile snmpd with that change.

I recompiled. The OID with big size worked perfectly well, with a big string (around 50000 bytes). But unfortunately (here comes the problem) the initial scalar OIDs added by means of the dynamic loadable module didn't work: the response for a command snmpget is always "No Such Object available on this agent at this OID".

More investigation and debugging. I see the following:


  1.  Function dlmod_load_module  is called (dlmod.c)
  2.  Inside that function, function dl_init is called in turn
  3.  From my dynamic loadable module, the function init_... is called (I checked it adding it a return value and capturing it in function dlmod_load_module and showing by means of DEBUGMSGTL)  but I don't see the log at the beginning of function init_... (I use "DEBUGMSGTL"). So this leads me to suspect there is some problem. I have investigated a lot but with no results ...

Any ideas?

Thank you very much.
Jose.