I have implemented an AgentX daemon for Net-SNMP based on the tutorial
on the web site. This implements SNMP GET requests for a MIB with a few
dozen scalar variables. It works fine but is very simple. I need to
further develop it. 

As an example, I want to periodically update a variable from my
application, and when there is a GET request for it, supply a scalar
that is the change since the last request. This requires that when a
request is made I remember the value at that time, for the subsequent
call. Maybe there is a role for a cache handler here. I am not sure.

It seems the best way is to use the 'handler' callback functions. The
problem I am finding with doing this is that there is apparently no
high-level roadmap that defines the terms, outlines the sequence of
steps and so on. It is true that there is some documentation based on
doxygen analysis of the code, but it is hard to know where to begin with
this, and not every function has this documentation.

I have scanned the available documentation, man pages, doxygen docs and
source code, and the mailing list archives for information on this
topic, and there seems to be very little information available. I find
this surprising because it seems to be an important area. The lack of
questions suggests that there is in fact some clear documentation
somewhere, and I have missed it. Unfortunately AGENT.txt seems to deal
only with V4 APIs, even in the most recent source code.

I will eventually absorb the source code and understand how to use this
facility, but in the meantime I would appreciate any roadmap-like
information that people can supply. The kind of thing I am interested in
is

- what do all the terms used mean? Examples are 'helper handler', 'mib
handler', 'handler chain', 'access method', 'inject', 'serialize
handler'. This terminology seems well established - is there a
reference?
- what is the sequence of processing steps for a GET request and where
do 'handlers' fit into that.
- for each function, what do all its parameters mean, what is its return
value and how does it relate to other function.
- for each struct, what do all its data members mean?

I apologize in advance if I have missed the glaringly obvious, and if
so, would appreciate being directed to the righteous path.

Thanks
gbp9848



-------------------------------------------------------
This SF.Net email sponsored by Black Hat Briefings & Training.
Attend Black Hat Briefings & Training, Las Vegas July 24-29 - 
digital self defense, top technical experts, no vendor pitches, 
unmatched networking opportunities. Visit www.blackhat.com
_______________________________________________
Net-snmp-coders mailing list
[EMAIL PROTECTED]
https://lists.sourceforge.net/lists/listinfo/net-snmp-coders

Reply via email to