NetSNMP::agent - Perl extension for the net-snmp agent.

  use NetSNMP::agent;

  my $agent = new NetSNMP::agent('Name' => 'my_agent_name');

This module implements an API set to make a SNMP agent act as a snmp agent, a snmp subagent (using the AgentX subagent protocol) and/or embedded perl-APIs directly within the traditional net-snmp agent demon.

Also see the tutorial about the genaral Net-SNMP C API, which this module implements in a perl-way, and a perl specific tutorial at:

  http://www.net-snmp.org/tutorial-5/toolkit/

    	use NetSNMP::agent (':all');
    	use NetSNMP::ASN qw(ASN_OCTET_STR);

        my $value = "hello world";
	sub myhandler {
	    my ($handler, $registration_info, $request_info, $requests) = @_;
	    my $request;

	    for($request = $requests; $request; $request = $request->next()) {
		my $oid = $request->getOID();
		if ($request_info->getMode() == MODE_GET) {
		    # ... generally, you would calculate value from oid
		    if ($oid == new NetSNMP::OID(".1.3.6.1.4.1.8072.9999.9999.7375.1.0")) {
			$request->setValue(ASN_OCTET_STR, $value);
		    }
		} elsif ($request_info->getMode() == MODE_GETNEXT) {
		    # ... generally, you would calculate value from oid
		    if ($oid < new NetSNMP::OID(".1.3.6.1.4.1.8072.9999.9999.7375.1.0")) {
			$request->setOID(".1.3.6.1.4.1.8072.9999.9999.7375.1.0");
			$request->setValue(ASN_OCTET_STR, $value);
		    }
		} elsif ($request_info->getMode() == MODE_SET_RESERVE1) {
		    if ($oid != new NetSNMP::OID(".1.3.6.1.4.1.8072.9999.9999.7375.1.0")) {  # do error checking here
			$request->setError($request_info, SNMP_ERR_NOSUCHNAME);
		    }
		} elsif ($request_info->getMode() == MODE_SET_ACTION) {
		    # ... (or use the value)
		    $value = $request->getValue();
		}
	    }

	}

	my $agent = new NetSNMP::agent(
				# makes the agent read a my_agent_name.conf file
    				'Name' => "my_agent_name",
    				'AgentX' => 1
    				);
	}

    	$agent->register("my_agent_name", ".1.3.6.1.4.1.8072.9999.9999.7375",
                         \&myhandler);

	my $running = 1;
	while($running) {
    		$agent->agent_check_and_process(1);
	}

	$agent->shutdown();

        # place this in a .pl file, and then in your snmpd.conf file put:
        #    perl do '/path/to/file.pl';

	use NetSNMP::agent;
	my $agent;

	sub myhandler {
	    my ($handler, $registration_info, $request_info, $requests) = @_;
	    # ...
	}

	$agent = new NetSNMP::agent(
    				'Name' => 'my_agent_name'
    				);

    	$agent->register("my_agent_name", ".1.3.6.1.4.1.8072.9999.9999.7375",
                         \&myhandler);

	$agent->main_loop();

    new ( OPTIONS )
	This is the constructor for a new NetSNMP::agent object.

    Possible options are:

    	Name	- Name of the agent (optional, defaults to "perl")
                  (The snmp library will read a NAME.conf snmp
                  configuration file based on this argument.)
    	AgentX	- Make us a sub-agent (0 = false, 1 = true)
                  (The Net-SNMP master agent must be running first)
    	Ports	- Ports this agent will listen on (EG: "udp:161,tcp:161")

    Example:

	$agent = new NetSNMP::agent(
    				 'Name' => 'my_agent_name',
    				 'AgentX' => 1
    				 );

    register (NAME, OID, \&handler_routine )
    	Registers the callback handler with given OID.

    	$agent->register();

	A return code of 0 indicates no error.

    agent_check_and_process ( BLOCKING )
    	Run one iteration of the main loop.

    	BLOCKING - Blocking or non-blocking call. 1 = true, 0 = false.

    	$agent->agent_check_and_process(1);

    main_loop ()
    	Runs the agent in a loop. Does not return.

    shutdown ()
	Nicely shuts down the agent or sub-agent.

	$agent->shutdown();

    handler ( HANDLER, REGISTRATION_INFO, REQUEST_INFO, REQUESTS )

    	The handler is called with the following parameters:

	HANDLER 		- FIXME
    	REGISTRATION_INFO 	- what are the correct meanings of these?
    	REQUEST_INFO		-
    	REQUESTS		-

    Example handler:

	sub myhandler {
	    my ($handler, $reg_info, $request_info, $requests) = @_;
	    # ...
	}

The handler subroutine will be called when a SNMP request received by the agent for anything below the registered OID. The handler is passed 4 arguments: $handler, $registration_info, $request_info, $requests. These match the arguments passed to the C version of the same API. Note that they are not entirely complete objects but are functional "enough" at this point in time.

    getMode ()
    	Returns the mode of the request. See the MODES section for
    	list of valid modes.

	$mode = $request->getMode();

    getRootOID ()
	Returns a NetSNMP::OID object that describes the registration
	point that the handler is getting called for (in case you
	register one handler function with multiple OIDs, which should
	be rare anyway)

    	$root_oid = $request->getRootOID();

    next ()
    	Returns the next request in the list or undef if there is no
    	next request.

    	$request = $request->next();

    getOID ()
	Returns the oid of the request (a NetSNMP::OID class).

	$oid = $request->getOID();

    setOID (new NetSNMP::OID("someoid"))
	Sets the OID of the request to a passed oid value.  This
	should generally only be done during handling of GETNEXT
	requests.

	$request->setOID(new NetSNMP::OID("someoid"));

    getValue ()
	Returns the value of the request. Used for example when
	setting values.

    	$value = $request->getValue();

    	FIXME: how to get the type of the value? Is it even available?
               [Wes: no, not yet.]

    setValue ( TYPE, DATA )
	Sets the data to be returned to the daemon.

    	Returns 1 on success, 0 on error.

    	TYPE - Type of the data. See NetSNMP::ASN for valid types.
    	DATA - The data to return.

	$ret = $request->setValue(ASN_OCTET_STR, "test");

    setError ( REQUEST_INFO, ERROR_CODE )
	Sets the given error code for the request. See the ERROR CODES
	section for list of valid codes.

    	$request->setError($request_info, SNMP_ERR_NOTWRITABLE);

    getProcessed ()
    	The processed flag indicates that a request does not need to
    	be dealt with because someone else (a higher handler) has
    	dealt with it already.

    	$processed = $request->getProcessed();

    setProcessed ( PROCESSED )
	Sets the processed flag flag in the request.  You generally
	should not have to set this yourself.

	PROCESSED - 0 = false, 1 = true

	$request->setProcessed(1);

    getDelegated ()
	If you can handle a request in the background or at a future
	time (EG, you're waiting on a file handle, or network traffic,
	or ...), the delegated flag can be set in the request.  When
	the request is processed in the future the flag should be set
	back to 0 so the agent will know that it can wrap up the
	original request and send it back to the manager.  This has
	not been tested within perl, but it hopefully should work.

	$delegated = $request->getDelegated();

    setDelegated ( DELEGATED )
    	Sets the delegated flag.

    	DELEGATED - 0 = false, 1 = true

    	$request->setDelegated(1);

    getRepeat ()
	The repeat flag indicates that a getbulk operation is being
	handled and this indicates how many answers need to be
	returned.  Generally, if you didn't register to directly
	handle getbulk support yourself, you won't need to deal with
	this value.

    	$repeat = $request->getRepeat();

    setRepeat ( REPEAT )
	Sets the repeat count (decrement after answering requests if
	you handle getbulk requests yourself)

	REPEAT -  repeat count FIXME

	$request->setRepeat(5);

	MODE_GET
	MODE_GETBULK
	MODE_GETNEXT
	MODE_SET_ACTION
	MODE_SET_BEGIN
	MODE_SET_COMMIT
	MODE_SET_FREE
	MODE_SET_RESERVE1
	MODE_SET_RESERVE2
	MODE_SET_UNDO

	SNMP_ERR_NOERROR
	SNMP_ERR_TOOBIG
	SNMP_ERR_NOSUCHNAME
	SNMP_ERR_BADVALUE
	SNMP_ERR_READONLY
	SNMP_ERR_GENERR
	SNMP_ERR_NOACCESS
	SNMP_ERR_WRONGTYPE
	SNMP_ERR_WRONGLENGTH
	SNMP_ERR_WRONGENCODING
	SNMP_ERR_WRONGVALUE
	SNMP_ERR_NOCREATION
	SNMP_ERR_INCONSISTENTVALUE
	SNMP_ERR_RESOURCEUNAVAILABLE
	SNMP_ERR_COMMITFAILED
	SNMP_ERR_UNDOFAILED
	SNMP_ERR_AUTHORIZATIONERROR
	SNMP_ERR_NOTWRITABLE

Please mail the net-snmp-users@lists.sourceforge.net mailing list for help, questions or comments about this module.

Module written by: Wes Hardaker <hardaker@users.sourceforge.net>

Documentation written by: Toni Willberg <toniw@iki.fi> Wes Hardaker <hardaker@users.sourceforge.net>

NetSNMP::OID(3), NetSNMP::ASN(3), perl(1).